Ingenieurwissenschaften und zugeordnete Tätigkeiten
Filtern
Erscheinungsjahr
- 2019 (976) (entfernen)
Dokumenttyp
- Vortrag (443)
- Zeitschriftenartikel (257)
- Posterpräsentation (116)
- Beitrag zu einem Tagungsband (104)
- Sonstiges (18)
- Forschungsbericht (10)
- Buchkapitel (9)
- Dissertation (6)
- Monografie (3)
- Zeitschriftenheft (Herausgeberschaft für das komplette Heft) (3)
Sprache
- Englisch (731)
- Deutsch (235)
- Mehrsprachig (8)
- Russisch (1)
- Spanisch (1)
Schlagworte
- Additive Manufacturing (47)
- Corrosion (45)
- Korrosion (33)
- Additive manufacturing (29)
- Additive Fertigung (20)
- Microstructure (17)
- Nanoparticles (17)
- Fluorescence (16)
- Computed tomography (15)
- Mechanochemistry (14)
- Residual stress (14)
- Nanoparticle (13)
- Quantum yield (13)
- Boehmite (12)
- Glass (12)
- In situ (12)
- Laser implantation (12)
- Lifetime (12)
- MIC (12)
- Surface functionalization (12)
- Thermografie (12)
- Welding (12)
- 316L (11)
- Laser beam welding (11)
- TiB2 (11)
- Wasserstoff (11)
- Computed Tomography (10)
- Hydrogen (10)
- Laser-induced periodic surface structures (LIPSS) (10)
- Nano (10)
- Nanocomposites (10)
- Nichtrostender Stahl (10)
- SAXS (10)
- Simulation (10)
- Thermography (10)
- Diffraction (9)
- Dye (9)
- Eigenspannungen (9)
- Friction (9)
- Surface texturing (9)
- TED-GC-MS (9)
- Wear (9)
- 3D printing (8)
- Carbon steel (8)
- Deckschichtbildung (8)
- Degradation (8)
- Korrosionsschutz (8)
- Magnetocaloric (8)
- Material Science (8)
- Nanomaterial (8)
- Photoluminescence (8)
- Qualitätssicherung (8)
- Steel (8)
- Zerstörungsfreie Prüfung (8)
- AISI D2 (7)
- Ageing (7)
- Applications (7)
- Gelartige Elektrolyte (7)
- Hochfeste Feinkornbaustähle (7)
- Kaltrisse (7)
- Laser Metal Deposition (7)
- Mechanical properties (7)
- Methanogens (7)
- NIR (7)
- Neutron Diffraction (7)
- Numerical simulation (7)
- Polymer (7)
- Polymers (7)
- Quantum dot (7)
- Schweißen (7)
- Synthesis (7)
- 3D Druck (6)
- CCS (6)
- Ceramic (6)
- Duplex (6)
- Energy harvesting (6)
- Epoxy (6)
- Fatigue (6)
- Femtosecond laser (6)
- Femtosecond laser ablation (6)
- Gefahrgut (6)
- Gefahrstoff (6)
- Implant-Test (6)
- Ink (6)
- KorroPad (6)
- Lanthanide (6)
- Laserstrahlschweißen (6)
- Low Cycle Fatigue (6)
- MAG-Schweißen (6)
- Microplastics (6)
- Nanocomposite (6)
- Non-destructive testing (6)
- Normung (6)
- Oxidation (6)
- Pitting (6)
- Prüfmethode (6)
- Ringversuch (6)
- Sensor (6)
- Validierung (6)
- Water content (6)
- AIS (5)
- AKR (5)
- AM (5)
- Archaeometry (5)
- Atomic Force Microscopy (AFM) (5)
- CO2 (5)
- Calibration (5)
- Cement (5)
- Characterization (5)
- Coating (5)
- Crack growth (5)
- Creep-resistant steel (5)
- Crystallization (5)
- Cyclization (5)
- Electron microscopy (5)
- Explosionsschutz (5)
- Finite element method (5)
- Flow cytometry (5)
- Hybrid Laser Arc Welding (5)
- Inks (5)
- Korrosionsprüfung (5)
- Künstliche Bewitterung (5)
- Laser Powder Bed Fusion (5)
- MALDI-TOF MS (5)
- Mechanical strength (5)
- Method (5)
- Modeling (5)
- Multiplexing (5)
- NDT (5)
- Non-Destructive testing (5)
- Photophysics (5)
- Polyaniline (5)
- Polylactide (5)
- Pyrotechnik (5)
- Quality assurance (5)
- Quantum dots (5)
- Reference materials (5)
- Residual Stress (5)
- Rigid amorphous fraction (5)
- SLM (5)
- Sicherheitstechnische Kenngrößen (5)
- Solidification cracking (5)
- Standardisation (5)
- Surface (5)
- Synchrotron (5)
- Ti-6Al-4V (5)
- Wärmeführung (5)
- X-ray refraction (5)
- X38CrMoV5-3 (5)
- XRD (5)
- Zink (5)
- Adjustment calculation (4)
- Aluminium (4)
- Analytische Zentrifuge (4)
- Assay (4)
- Bead (4)
- Biodiesel (4)
- Broadband dielectric spectroscopy (4)
- Catalysis (4)
- Composite (4)
- Copper (4)
- Coptic (4)
- Crevice corrosion (4)
- Direct energy deposition (4)
- Durability (4)
- ECA (4)
- EPDM (4)
- Eddy Current (4)
- Encoding (4)
- Environment (4)
- GMR (4)
- Geothermal (4)
- HNBR (4)
- Highspeed-plasma-laser-cladding (4)
- Hybride Gemische (4)
- IR (4)
- Innenhydrophobierung (4)
- Keyhole mode welding (4)
- Klebfestigkeit (4)
- L-PBF (4)
- LBM (4)
- Laser-induced X-ray emission (4)
- Laser-induced periodic surface structures, LIPSS (4)
- MOF (4)
- Manuscripts (4)
- Martensite (4)
- Mechanism (4)
- Metals (4)
- Mikroplastik (4)
- Mikrostruktur (4)
- NMR (4)
- Neutron diffraction (4)
- Open data (4)
- Open science (4)
- Particle size distribution (4)
- Polymers of intrinsic microporosity (4)
- Porosity (4)
- Post weld heat treatment (4)
- Radiation protection (4)
- Raman Spectroscopy (4)
- Residual stresses (4)
- Schadensanalyse (4)
- Schleifen (4)
- Specific heat spectroscopy (4)
- Surface chemistry (4)
- Thin films (4)
- Traceability (4)
- Transmission electron microscopy (4)
- UHPC (4)
- Ultraschall (4)
- Ultrashort laser material interaction (4)
- X-Ray Imaging (4)
- X-Ray imaging (4)
- X-ray computed tomography (4)
- XPS (4)
- Zinküberzüge (4)
- AFM (3)
- ATR (3)
- Absorption edge tomography (3)
- Additive Manufacturing (AM) (3)
- Alloy 2618A (3)
- Analytik (3)
- Anerkennungen (3)
- Anisotropy (3)
- Archaea (3)
- Atmosphärische Korrosion (3)
- AuNP (3)
- Auslagerungsversuche (3)
- Ausnahmegenehmigungen (3)
- Austenitic stainless steels (3)
- Barcoding (3)
- Bending modulus (3)
- Bimetallkorrosion (3)
- Carbon capture (3)
- Carbon nanotubes (3)
- Catalyst (3)
- Ceramic spring (3)
- Ceramics (3)
- Chemical composition (3)
- Composites (3)
- Corrosion monitoring (3)
- Crosslinking (3)
- Cyclic R-curve (3)
- DCB (3)
- Damage detection (3)
- Deposition welding (3)
- Dielectric spectroscopy (3)
- Diesel (3)
- Digitalization (3)
- Diopside (3)
- Discotic Liquid Crystals (3)
- Dosimetry (3)
- EBSD (3)
- EPMA (3)
- Einstufung (3)
- Electromagnetic Weld Pool Support (3)
- Element transport (3)
- End crater (3)
- Energy transfer (3)
- Erstarrungsriss (3)
- Explosionsgrenzen (3)
- FAME (3)
- FKM (3)
- FTIR (3)
- Festlegungen (3)
- Flame retardant (3)
- Flash DSC (3)
- Freibewitterung (3)
- Full Penetration (3)
- Full-Notch Creep Test (FNCT) (3)
- Geant4 (3)
- Graphene (3)
- Guideline (3)
- Haftfestigkeit (3)
- Harmonisation (3)
- Heat conduction (3)
- High power laser beam welding (3)
- High temperature corrosion (3)
- High-strength steels (3)
- Hot-Stamping (3)
- Hybrid laser-arc welding (3)
- IgG (3)
- InP (3)
- Inconel 718 (3)
- Indium phosphide (3)
- Inter-laboratory comparison (3)
- Kunststoffe (3)
- LCF (3)
- LIBS TIG welding (3)
- LLG (3)
- LPA (3)
- Laminography (3)
- Large-scale test (3)
- Laser Powder Bed Fusion (L-PBF) (3)
- Laser Pulver Auftragsschweißen (3)
- Laser beam melting (3)
- Laser metal deposition (3)
- Laserimplantation (3)
- MCS (3)
- Magnetohydrodynamics (3)
- Materials (3)
- Materials Science (3)
- Materials science (3)
- Microdosimetry (3)
- Micromagnetism (3)
- Moisture clog (3)
- Monte-Carlo simulation (3)
- Mueller-Matrix imaging ellipsometry (3)
- Nanofibers (3)
- Nanomaterialien (3)
- Non-destructiv testing (3)
- OECD (3)
- OOMMF (3)
- Orientation (3)
- Passivität (3)
- Phase transformation (3)
- Plastic (3)
- Polycarbonate (3)
- Polymer blends (3)
- Polymere (3)
- Polyurethane (3)
- Pores (3)
- Process monitoring (3)
- Protein G (3)
- Prüfrichtlinie (3)
- Prüfverfahren (3)
- Reflectography (3)
- Research data management (3)
- Restraint (3)
- Rheology (3)
- Richtlinien (3)
- Rigidity (3)
- Roughness (3)
- Rubber (3)
- Röntgenrefraktion (3)
- SWIR (3)
- Sauerstoff (3)
- Scanning electron microscopy (3)
- Selective Laser Melting (3)
- Selective laser melting (3)
- Sicherheitstechnische Bewertung (3)
- Slurry (3)
- Small-angle scattering (3)
- Spectroscopic ellipsometry (3)
- Spectroscopy (3)
- Spectroskopic Imaging (3)
- Stress relief cracking (3)
- Structural health monitoring (3)
- Sulfidation (3)
- Superplasticizer (3)
- Synchrotron tomography (3)
- TEKKEN-Test (3)
- Temperature (3)
- Tensile properties (3)
- Testing (3)
- Thermoelectrics (3)
- Thick Materials (3)
- Tribology (3)
- Tunnel (3)
- Uncertainty (3)
- Upconversion nanoparticle (3)
- Utilization (3)
- Water speciation (3)
- Weld pool shape (3)
- X-ray diffraction (3)
- X-ray scattering (3)
- XRF (3)
- Zinc coatings (3)
- Zugeigenschaften (3)
- Zulassungen (3)
- µ-gravity (3)
- Überzüge (3)
- 1H-NMR (2)
- 3D (2)
- AISI 316L (2)
- AKR-Betonversuche (2)
- ALD-Hybridprozesse (2)
- ASR (2)
- Absolute fluorometry (2)
- Acoustic Emission (2)
- Acoustic levitation (2)
- Adhesive joint (2)
- Adhäsion (2)
- Adsorbed layer (2)
- Adsorption (2)
- Advanced Materials (2)
- Advanced high strength steel (2)
- Aerosol measurements (2)
- Al2O3-Schichten (2)
- Altern (2)
- Antibody coating (2)
- Antikörper (2)
- Arabic Recipes (2)
- Armaturenprüfung (2)
- Artificial weathering (2)
- Atomic Layer Deposition (2)
- Auftragschweißen (2)
- Ausgleichungsrechnung (2)
- BAMline (2)
- BDS (2)
- Baustoffe (2)
- Bauteilprüfung (2)
- Beständigkeit (2)
- Beständigkeitsbewertungen (2)
- Betonfahrbahn (2)
- Bioactive glass (2)
- Bioceramics (2)
- Biofilm (2)
- Biofilmbildung (2)
- Biosensor (2)
- Boundary element method (2)
- Brechungsindex (2)
- Brexit (2)
- Brittle fracture (2)
- Building Materials (2)
- Bulging effect (2)
- C3A (2)
- CAT-Technologie (2)
- CCU (2)
- CCUS (2)
- CFK (2)
- CFRP (2)
- CLP (2)
- CLP-Verordnung (2)
- CMAS (2)
- COD-AGE (2)
- CT (2)
- Capture (2)
- Carbon (2)
- Chaboche model (2)
- Chemikalienrecht (2)
- Chemisch instabile Gase (2)
- Cleavable probe (2)
- Coarsening (2)
- Compatibility (2)
- Compatibility evaluations (2)
- Composite-Druckgefäß (2)
- Compressive Cyclic loading (2)
- Condensate (2)
- Condensation (2)
- Contact resonance (2)
- Continuum mechanics (2)
- Copolymer (2)
- Corrosion Fatigue (2)
- Corrosion inhibition (2)
- Corrosion products (2)
- Corrosion rate (2)
- Corrosion testing (2)
- Crack Propagation (2)
- Crack propagation (2)
- Crevice (2)
- Crystal plasticity (2)
- Cultural heritage (2)
- Cytotoxicity (2)
- DED (2)
- DIN EN 16516 (2)
- DLO (2)
- DNA (2)
- DNA damage (2)
- Damage (2)
- Dangerous goods (2)
- Database (2)
- Deckschichten (2)
- Defokussierung (2)
- Dehnungsfehler (2)
- Delayed addition (2)
- Desiccation (2)
- Desinfection (2)
- Diffusion (2)
- Digital (2)
- Digital image correlation (2)
- Digital material representation (2)
- Digital twin (2)
- Dilatometry (2)
- Direct Energy Deposition (2)
- Direct Laser Metal Deposition (2)
- Distributed fibre optic sensing (2)
- Drinking (2)
- Druckbehältern (2)
- Dual phase steel (2)
- Duplexstahl (2)
- EOS (2)
- EPR (2)
- EU FP7 project NanoValid (2)
- Early hydration (2)
- Early oxidation (2)
- Elastic constants (2)
- Electron energy (2)
- Electron probe microanalysis (EPMA) (2)
- Electronic Detonators (2)
- Elektrochemie (2)
- Elemental composition (2)
- Ellipsometrie (2)
- Ellipsometry (2)
- End-crater (2)
- Endkrater (2)
- Energetic Materials (2)
- Energy deposit (2)
- Energy distribution (2)
- Environmental Simulation (2)
- Erdboden (2)
- Exchange interaction (2)
- Explosivstoffe (2)
- Extensometer (2)
- FT-IR (2)
- Faserverbund (2)
- Faserverbundwerkstoff (2)
- Fatigue crack growth (2)
- Fatigue crack propagation (2)
- FeCr- alloys (2)
- Ferromagnetism (2)
- Fiber reinforced polymer (2)
- Finite-Elemente-Methode (2)
- Formaldehyd (2)
- Fracture mechanics (2)
- Fracture surface analysis (2)
- Fragmentation (2)
- Fraktografie (2)
- Frequenzanalyse (2)
- Fräsen (2)
- Fume (2)
- Funtional Groups (2)
- GFK (2)
- GFRP (2)
- GHS (2)
- GTN model (2)
- Gas-Staub-Gemische (2)
- Gefährliche Stoffe (2)
- Gel-type electrolytes (2)
- Geothermal energy (2)
- Glass transition (2)
- Glass-ceramic (2)
- Gold (2)
- HAZPRED (2)
- HI-Tension (2)
- HPC (2)
- Haftvermittler (2)
- Harmonised Standards (2)
- Hazardous substances (2)
- Heat treatment (2)
- Heizöl (2)
- Heißriss (2)
- Herceptin (2)
- High Alloyed Steel (2)
- High Temperature Testing (2)
- High temperature (2)
- High-entropy alloys (2)
- High-performance concrete (2)
- High-pressure (2)
- High-strength concrete (2)
- High-strength steel (2)
- Hochfester Feinkornbaustahl (2)
- Hot cracking (2)
- Hot steam (2)
- Hybrid composite pressure vessel (2)
- Hydrogen assisted cracking (2)
- Hydrogen-assisted cracking (2)
- Hydrothermal treatment (2)
- Höherfester Feinkornbaustahl (2)
- IN 718 (2)
- Immunoassay (2)
- Immunocapture (2)
- Immunoglobulins (2)
- Immunoprecipitation (2)
- Immunosensor (2)
- Impurities (2)
- In situ Monitoring (2)
- In situ measurement (2)
- Innovation (2)
- Integrated analysis (2)
- Integrating sphere spectroscopy (2)
- Integrierte Analyse (2)
- Interlaboratory comparison (2)
- Internal friction (2)
- Interphase (2)
- Iridium-titanium mixed oxides (2)
- Iron (2)
- Irradiation (2)
- Kaltrissprüfung (2)
- Kavitation (2)
- Kennzeichnung (2)
- Keyhole mode laser beam welding (2)
- Kikuchi pattern (2)
- Kleb- und Haftfestigkeit (2)
- Kleinprobenprüfung (2)
- Kontinuumsmechanik (2)
- Korrosionsuntersuchungen (2)
- Kältemittel (2)
- LEE (2)
- LIMS (2)
- LMD (2)
- LME (2)
- LTT (2)
- Lamb waves (2)
- Landau Lifshitz equation (2)
- Laser (2)
- Laser Beam Melting (2)
- Laser Beam Welding (2)
- Laser cladding (2)
- Laser dispersing (2)
- Laserhybridschweißen (2)
- Laserschutz (2)
- Layer formation (2)
- Layerwise (2)
- Lean Duplex (2)
- Lebensdauerversuche (2)
- Localised corrosion (2)
- Lochkorrosion (2)
- Longitudinal Wave (2)
- Lubricants (2)
- MHD (2)
- MVT (2)
- Magnesium alloy (2)
- Magnetic moment (2)
- Magnetocaloric effect (2)
- Marktüberwachung (2)
- Mass spectrometry (2)
- Material degradation (2)
- Material science (2)
- Materialbearbeitung (2)
- Mehrprobenprüfung (2)
- Melting (2)
- Mesoporous thin films (2)
- Messunsicherheit (2)
- Metallene Werkstoffe (2)
- Metallic seal (2)
- Metallische Materialien (2)
- Metal–organic frameworks (2)
- Methane (2)
- Metrology (2)
- Microbiologically influenced corrosion (2)
- Microcracking (2)
- Microhardness (2)
- Mikroskaliert (2)
- Mixed Ca-K-Na phosphates (2)
- Modelling (2)
- Moisture transport (2)
- Molecular masses (2)
- Molten pool dynamics (2)
- Monte Carlo (2)
- Multi-layered system (2)
- Multiple cracks (2)
- Müller-Matrix-Ellipsometrie (2)
- NEXAFS (2)
- NMR spectroscopy (2)
- Na and K rhenanites (2)
- NanoSIMS (2)
- Nanocharacterisation (2)
- Nanomechanics (2)
- Nanoplastics (2)
- Nanoskaliert (2)
- Nanostructure (2)
- NiCrBSi (2)
- Nichtmetallische Materialien (2)
- Non destructive analytical techniques (2)
- Non destructive testing (2)
- Non-metallic inclusions (2)
- Nondestructive testing (2)
- Normen (2)
- OH radicals (2)
- Oberflächenenergie (2)
- Oberflächengeometrie (2)
- Object oriented micromagnetic framework (2)
- On-site mixed Explosives (2)
- Online Process Monitoring (2)
- Optical Tomography (2)
- Organic peroxides (2)
- Oriented immobilization (2)
- PEG (2)
- POD (2)
- Papyrus (2)
- Partial penetration (2)
- Particle gas emission (2)
- Particle size distributuion (2)
- Phase composition (2)
- Phase diagram (2)
- Phase transformations (2)
- Phononischer Kristall (2)
- Photon counting detector (2)
- Photoresist (2)
- Physikalische Gefahren (2)
- Pipeline (2)
- Pipeline steel X120 (2)
- Pipelines (2)
- Pitting corrosion (2)
- Plasma (2)
- Plasma-Transferred-Arc (2)
- Plume (2)
- Polyamide 12 (2)
- Polycarboxylate ether (PCE) (2)
- Polyethylene (2)
- Polyethylene glycol (2)
- Polyethylene, PE-HD (2)
- Polymer bilayer coatings (2)
- Polymer materials (2)
- Polymer matrix composites (2)
- Polymer nanocomposites (2)
- Powder (2)
- Powder Bed Fusion (2)
- Presshärten (2)
- Probe (2)
- Probengrößeneffekt (2)
- Process simulation (2)
- Protein A (2)
- Proximity-enhanced reaction (2)
- Prozesskette (2)
- Prüfmethoden (2)
- Pufferschichten (2)
- Pyrotechnics (2)
- QSPR (2)
- Quantitative Analysis (2)
- RSW (2)
- Radiationtherapy (2)
- Radioactive decay (2)
- Raman spectroscopy (2)
- Reheat cracking (2)
- Resistance spot welding (2)
- Resonance frequency (2)
- Rissbildung in Stahl (2)
- Round robin test (2)
- Rubber seal (2)
- Rundnaht (2)
- Röntgenbeugung (2)
- Röntgenemission (2)
- Scale-bridging (2)
- Scaled Boundary FEM (2)
- Schadenserkennung (2)
- Schallemission (2)
- Schallemissionsprüfung (2)
- Schallerzeuger (2)
- Schwingfestigkeit (2)
- Schädigung (2)
- Seal performance (2)
- Sekundärstrahlung (2)
- Selected Laser Melting (2)
- Self-reactive substances (2)
- Semiconductor nanocrystal (2)
- Sensibilisierung (2)
- Sensitization (2)
- Shore hardness (2)
- Silica beads (2)
- Silica nanoparticles (2)
- Silicon (2)
- Single particle spectroscopy (2)
- Sintering (2)
- Small angle scattering (2)
- Small-angle X-ray scattering (2)
- Soda-lime silicate glass (2)
- Soda-lime-silica glass (2)
- Software (2)
- Solidification (2)
- Spatter (2)
- Spectral sensitivity (2)
- Speed of sound (2)
- Stainless (2)
- Stainless Steel (2)
- Stainless steel (2)
- Standardization (2)
- Standards (2)
- Stochastic Landau Lifshitz Gilbert equation (2)
- Storage (2)
- Structural anomalies (2)
- Structural inhomogenities (2)
- Sulfate reducing bacteria (2)
- Superelliptic Lamé curves (2)
- Surface crystallization (2)
- Surface modification (2)
- Sustainability (2)
- Synthetic air (2)
- TMDSC (2)
- Tausalzeintrag (2)
- Technical Specification (2)
- Temeprature scaling (2)
- Temperature dependency (2)
- Temperature field (2)
- Temperaturschwankungen (2)
- Tensile Properties (2)
- Ternary quantum dots (2)
- Test method (2)
- Testing method (2)
- Thermal degradation (2)
- Thermal treatment (2)
- Thin polymer films (2)
- Thin polymeric films (2)
- Ti64 (2)
- TiAl5V4 (2)
- Titan (2)
- Titanium (2)
- Topografie (2)
- Tribofilm (2)
- Tribologie (2)
- Tungsten carbide (2)
- UN-GHS (2)
- UV degradation (2)
- Ultrakurze Laserpulse (2)
- Ultraschallunterstütztes Zerspanen (2)
- Ultrasonic Transducer (2)
- Ultrasonic testing (2)
- Upconversion (2)
- Upconversion nanoparticles (2)
- Utilization, and storage (CCUS) technology (2)
- VAMAS (2)
- VSSA (2)
- Validation (2)
- Variational calculus (2)
- Variationsrechnung (2)
- Verbundfestigkeit (2)
- Verifizierung (2)
- Virtual experiments (2)
- Water (2)
- Wear resistance (2)
- Weathering (2)
- Weld metal (2)
- Weld pool behavior (2)
- Weld pool shape approximation (2)
- Wellenprüfung (2)
- Werkstoffprüfung (2)
- Wind energy (2)
- Wirbelstromprüfung (2)
- X-ray CT (2)
- X-ray and electron diffraction (2)
- X-ray refraction techniques (2)
- X-ray-CT (2)
- Zero-g (2)
- Zerspanbarkeitsanalysen (2)
- Zinc coated steel (2)
- Zinkdeckschichten (2)
- Zirconia (2)
- Zonation (2)
- Zugversuch (2)
- Zuverlässigkeit (2)
- Zündenergie (2)
- Zündquellen (2)
- additive manufacturing (2)
- corrosion (2)
- fluorescence (2)
- low energy electrons (2)
- particle scattering (2)
- Überlappbereich (2)
- 16S rRNA gene (1)
- 18HLT01 MetVes II (1)
- 1D-Simulation (1)
- 2,6-diaminopyridine (1)
- 2D nanomaterials (1)
- 3D coherence scanning interferometry (CSI) (1)
- 3D imaging (1)
- 3D inspection (1)
- 3D-Printing (1)
- 3d structuring (1)
- 5G (1)
- 60 °C-Betonversuch (1)
- ABID (1)
- ACM (1)
- ADN Tabelle C (1)
- AEROSIL® OX50 (1)
- AET (1)
- AFM based test methods (1)
- AFM-IR (1)
- AFM-Kraft-Abstand-Kurven (1)
- AGIL (1)
- AIS QD (1)
- AISI 304L (1)
- AISI 321 stainless steel (1)
- AKR, Betonfahrbahndecke, Tausalzeintrag, Innenhydrophobierung (1)
- AM IN718 alloy (1)
- AXRD (1)
- Abrasion (1)
- Abrasive belt (1)
- Abtragende Glasbearbeitung (1)
- Accelerator (1)
- Acetone (1)
- Acoustic Emission (AE) (1)
- Acoustic emission (1)
- Acoustic emission analysis (1)
- Acoustic insulation (1)
- Acrylamide (1)
- Activation energy (1)
- Active Matter (1)
- Active thermography (1)
- Actuating materials (1)
- AdCo Explosives (1)
- Additiv (1)
- Additives (1)
- Admixture (1)
- Admixtures (1)
- Advanced high strength steels (1)
- Advanced materials (1)
- Affinity chromatography (1)
- Affinitätschromatographie (1)
- Affinitätsextraktion (1)
- Africa (1)
- Ageing behaviour (1)
- Ageing treatment (1)
- Aggressive environment (1)
- Aging tests (1)
- Aktive Thermographie (1)
- Akustischer Isolator (1)
- Al-Composite (1)
- Al-Cu-Li alloys (1)
- Al/SiO2 composite (1)
- Alcohols (1)
- Alite (1)
- Alkali-Kieselsäure Reaktion (1)
- Alkali-Kieselsäure-Reaktion (1)
- Alkali-activated materials (1)
- Alkali-silica reaction (1)
- Alkali-silica-reaction (1)
- Alkoxysilanes (1)
- Alpha (1)
- Alterung (1)
- Alumina (1)
- Aluminium-Druckguss (1)
- Aluminiumlegierungen (1)
- Aluminosilicate glasses (1)
- Aluminum alloy (1)
- Ameisensäure (1)
- Amplicon sequencing (1)
- Analysis (1)
- Anatase (1)
- Aneurism (1)
- Anisotropy estimate (1)
- Anoxia (1)
- Antibacterial (1)
- Antibodies (1)
- Antifouling surface coatings (1)
- Antifriction coefficient (1)
- Antimicrobial (1)
- Antiviral activity (1)
- Anwendungen (1)
- Approval (1)
- Aquifer (1)
- Arabic recipes (1)
- Arbitrary trajectories (1)
- Architecture (1)
- Arrhenius (1)
- Artungleiche Werkstoffe (1)
- Atemluftflasche (1)
- Atemschutz (1)
- Atomic force microscopy (1)
- Atomic fraction (1)
- Atomization (1)
- Aufbau von Festkörpern (1)
- Auftriebskräfte (1)
- Ausbildung (1)
- Auslaugung (1)
- Austenitic stainless steel (1)
- Autocorrelation (1)
- Automated expansion measurement (1)
- Automation (1)
- Automatische Dehnungsmessung (1)
- Automobilindustrie (1)
- BAM-Liste (1)
- BODIPY (1)
- BREXIT (1)
- BTS (1)
- Bacteria (1)
- Bacterial adhesion (1)
- Ball milling (1)
- Baumusterprüfungen (1)
- Bead-based assay (1)
- Beamline (1)
- Beanspruchungsanalyse (1)
- Beförderung gefährlicher Güter (1)
- Benannte Stellen (1)
- Bench braking sequence (1)
- Beschichtung (1)
- Bestimmung der Messunsicherheit (1)
- Beständigkeit in Biokraftstoffen (1)
- Beständigkeitsbewertung (1)
- Beta decay (1)
- Betriebsfestigkeit (1)
- Bewegtes Gitter (1)
- Bindemittel (1)
- Binnenwasserstraßen (1)
- Bio-based concrete (1)
- Biochip (1)
- Bioconjugation (1)
- Biofunctional Molecules (1)
- Biogene Brennstoffe (1)
- Biogeochemical cycling (1)
- Biomineralisation (1)
- Biopolymer (1)
- Biopolymers (1)
- Black Ink (1)
- Bloch wall (1)
- Blähen (1)
- Boehmite alumina (1)
- Boehmite nanoparticles (1)
- Bondline (1)
- Borosilikatglas (1)
- Brachytherapy (1)
- Braking load history (1)
- Brass (1)
- Breakdown strength (1)
- Brightness (1)
- Broadband dielectric microscopy (1)
- Bruchflächenanalyse (1)
- Bruchmechanik (1)
- Bubble formation (1)
- Build Angle (1)
- Bulge (1)
- Bulging (1)
- Bulk material (1)
- Bulk properties ageing (1)
- Bulk temperature (1)
- Bundesoberbehörden (1)
- Böden (1)
- Böhmit (1)
- C-C coupling (1)
- C. lap-shear (1)
- C3S (1)
- CAFTP (1)
- CALPHAD (1)
- CALPHAD databases analysis (1)
- CE-ICP-MS (1)
- CO2 Corrosion (1)
- CO2 separation membranes (1)
- CO2-Corrosion (1)
- CO2-Speicherung (1)
- CO2-storage (1)
- COK-12 (1)
- Cable (1)
- Calcination (1)
- Calcium cobaltite (1)
- Calcium peroxid (1)
- Calcium phosphate (1)
- Calculation time (1)
- Cancer (1)
- Cancer treatment (1)
- Carbide (1)
- Carbon Capture, Utilization and Storage (CCUS) (1)
- Carbon capture, utilization and storage technology (1)
- Carbon dioxide (1)
- Carbon dot (1)
- Carbon fibers (1)
- Carbon storage (1)
- Carrier gas hot extraction (1)
- Catalysts (1)
- Catch and release assay (1)
- Catechol (1)
- Cationic photocuring (1)
- Cavitation (1)
- Cell (1)
- Cell size (1)
- Cellulose (1)
- Cement admixtures (1)
- Cement hydration (1)
- Cement paste (1)
- Central Taurus (1)
- Centrifugal Adhesion Testing (1)
- Centrifugal Adhesion Testing (CAT) (1)
- Centrifugal Force (1)
- Certification Standard 22 (1)
- Certified reference materials (1)
- Certified standards (1)
- Characterisation (1)
- Chargenprüfung (1)
- Chemical admixtures (1)
- Chemical durability (1)
- Chemically Complex Alloy (1)
- Chemische Analyse (1)
- Chemo-mechanical coupling (1)
- Chloridbelastete Stahlbetonbauwerke (1)
- Chunky graphite (1)
- Circumferential weld (1)
- Circumferential welds (1)
- Civil Engineering (1)
- Classification (1)
- Cleavable linker (1)
- Click chemistry (1)
- Climate responsive materials (1)
- Cluster (1)
- Co (1)
- Co-axial monitoring (1)
- Co-crystal (1)
- CoO (1)
- Coal dust (1)
- Coarse-grained heat-affected zone (1)
- Cob (1)
- Cobalt (1)
- Cobalt and zinc oxides (1)
- Cocrystal (1)
- Codicology (1)
- Coefficient of thermal expansion (1)
- Coherent exchange (1)
- Cohesive Elements (1)
- Colored glasses (1)
- Combinatorial chemistry (1)
- Combinatorial polymer libraries (1)
- Community composition (1)
- Comparability of Measurement Results (1)
- Compatibility evaluation (1)
- Complex concentrated alloy (CCA) (1)
- Composite pressure vessel (1)
- Compression behavior (1)
- Compression set (1)
- Compression test (1)
- Compressive Stress (1)
- Computed tomography (CT) (1)
- Computer-Tomographie (1)
- Computertomographie (1)
- Concrete Prism Test at 60 °C (1)
- Concrete bridges (1)
- Concrete motorway pavements (1)
- Conductivity (1)
- Conductometry (1)
- Conference (1)
- Conjugates (1)
- Contact angle (1)
- Contact fatigue (1)
- Content of calcium peroxide (1)
- Controlled atmosphere (1)
- Convection coefficient (1)
- Copper-based wood preservatives (1)
- Coputed tomography (1)
- Cordierite (1)
- Core/shell quantum dot (1)
- Corrosion and storage (CCUS) technology (1)
- Corrosion pits (1)
- Corrosion product (1)
- Corrosion resistance (1)
- Coupled corrosive and mechanial load (1)
- Coupled corrosive/mechanical load (1)
- Crack (1)
- Crack arrest (1)
- Cracking (1)
- Creep (1)
- Cristobalite frameworks (1)
- Critical pitting temperature (1)
- Critical strain (1)
- Crosslinker (1)
- Crosslinking density (1)
- Cryogenic Engineering (1)
- Cryogenic Steel (1)
- Crystal Plasticity Modelling (1)
- Crystal Texture (1)
- Crystal orientation (1)
- Crystalline cones (1)
- Curie temperature (1)
- Curing (1)
- Curved surfaces (1)
- Cyclic (1)
- Cyclic J-integral (1)
- Cyclic R-curve analysis (1)
- Cyclic softening (1)
- Cycloaliphatic epoxy oligosiloxane (1)
- Cycloalyphatic epoxy oligosiloxane (1)
- D. aging (1)
- D. creep D. viscoelasticity (1)
- DED-L (1)
- DFG SPP 2005 (1)
- DIC assisted compression (1)
- DIN 50929-3 (1)
- DIN EN 717-1 (1)
- DIN EN ISO/IEC 17025:2018 (1)
- DMA (1)
- DPA (1)
- DRIFTS (1)
- Damage detection and localisation (1)
- Damage tolerant component design (1)
- Damping factor (1)
- Dangerous Goods (1)
- Dark-field transmission electron microscopy (DFTEM) (1)
- Data Processing (1)
- Data fusion (1)
- Data processing (1)
- Data storage (1)
- Dauerhaftigkeit (1)
- Dead Sea Scrolls (1)
- Dealloying (1)
- Declarations of conformity (1)
- Deep learning (1)
- Defect detection (1)
- Defect photoluminescence (1)
- Defects (1)
- Defekte Eigenspannung (1)
- Definition of nanomaterial (1)
- Deformation behavior (1)
- Denkmalpflege (1)
- Dense phase (1)
- Density Functional Theory (1)
- Destabilization (1)
- Deuterium (1)
- Diagnostic antibodies (1)
- Dichtmaterial (1)
- Dichtungswerkstoffe (1)
- Dielectric breakdown (1)
- Dielectric strength (1)
- Diesel Fuel (1)
- Digital Volume Correlation (1)
- Digitalisierung (1)
- Dipole moment (1)
- Directed Energy Deposition (1)
- Directed energy deposition (1)
- Dislocations (1)
- Dispersion of nano materials (1)
- Dissimilar metal weld overlays (1)
- Distortion (1)
- Distortion simulation (1)
- Distributed fiber optic sensing (1)
- Distributed fiber optic sensors (1)
- Distributed humidity sensor (1)
- Distributed sensor (1)
- Domain wall (1)
- Double complex salts (1)
- Drinking water (1)
- Drop test (1)
- Droplet (1)
- Droplet corrosion (1)
- Druckgasbehälter (1)
- Druckstabilität (1)
- Drug (1)
- Dual Energy Imaging (1)
- Dual energy (1)
- Dual sensing (1)
- Dual-Energy (1)
- Dual-energy (1)
- Ductile iron (1)
- Durability testing (1)
- Dye degradation (1)
- Dye labeling (1)
- Dynamic heterogeneity (1)
- Dynamic mechanical analysis (1)
- Dynamisch Mechanische Analyse (1)
- Dünne Schichten (1)
- E10 (Kraftstoff mit bis zu 10% Ethanol) (1)
- EASA (1)
- EC4SafeNano (1)
- EDX Analysis (1)
- EIS (1)
- ELISA (1)
- EMPIR (1)
- EMPIR project (1)
- ESI MS (1)
- Early sulfidation (1)
- Eddy current testing (1)
- Editorial (1)
- Editorial Board (1)
- Education (1)
- Eexisting structures (1)
- Efficient modelling (1)
- Eigenschaften (1)
- Eigenspannung (1)
- Einspanngrad (1)
- Einstufungskriterien (1)
- Elastic Constants (1)
- Elastin (1)
- Elastomerdichtung (1)
- Elastomere (1)
- Electrical conductivity (1)
- Electro-fused zirconia (1)
- Electro-thermomechnical model (1)
- Electrochemical characterisation (1)
- Electrochemical deposition (1)
- Electrochemical deposition (ECD) (1)
- Electrochemical impedance spectroscopy (1)
- Electrochemical potentiodynamic reactivation (1)
- Electrochemical sensing (1)
- Electrochemistry (1)
- Electrode geometry (1)
- Electromagnetic radiation (1)
- Electromagnetic scattering (1)
- Electromagnetic stirring (1)
- Electromagnetic weld pool support (1)
- Electromicroscopy (1)
- Electrospun fibers (1)
- Elektromagnetische Porenreduktion (1)
- Elektromagnetische Schmelzbadunterstützung (1)
- Elektromagnetsiche Schmelzbadbeeinflussung (1)
- Elektronische Zündesysteme (1)
- Elemenet transport (1)
- Elevated temperatures (1)
- Ellipsometric porosimetry (1)
- Emerging technologies (1)
- Emissionsprüfkammer (1)
- Emissionsprüfung (1)
- Enamels (1)
- Endurance Limit (1)
- Energiedissipation im Kontakt (1)
- Energy (1)
- Energy systems (1)
- Engine oil design (1)
- Engine oil testing (1)
- Engineering (1)
- Engineering applications (1)
- Environmental Stress Cracking (ESC) (1)
- Environmental simulation (1)
- Environmental stress cracking (1)
- Environmental stress cracking (ESC) (1)
- Environmentally assisted cracking (1)
- Epoxy conversion degree (1)
- Epoxy-Anhydrid Duroplast (1)
- Equivalent heat source (1)
- Ermüdung (1)
- Europium (1)
- Europäisches Übereinkommen (1)
- Evolution of bulk properties (1)
- Exchange length (1)
- Excitation power density (1)
- Experimental design (1)
- Explosion limits (1)
- Explosion protection (1)
- Explosionsartiges Abplatzen (1)
- Explosionsgefährliche Eigenschaften (1)
- Explosive spalling (1)
- Explosivplattieren (1)
- Explosivstoofe (1)
- Exposed metal sites (1)
- Extracellualr vesicles (1)
- Extracellular matrix (1)
- Extracellular vesicles (EV) (1)
- FIB/SEM (1)
- FLIM (1)
- FPLC (1)
- FRET (1)
- FSDC (1)
- FTIR spectroscopy (1)
- Fabrication (1)
- Facades (1)
- Facilitated activation (1)
- Fahrbahndeckenbetone (1)
- Failure test (1)
- Faser-Kunststoff-Verbunde (1)
- Faserkunststoffverbunde (1)
- Fast scanning calorimeter (1)
- Fast scanning calorimetry (1)
- Fast scanning calormetry (1)
- Fatigue Crack Propagation (1)
- Fatigue Life Evaluation (1)
- Fatigue S-N curve (1)
- Fatigue Testing (1)
- Fatigue crack propagation stages (1)
- Fatigue strength (1)
- Fatigue strength and life (1)
- Fatigue tests (1)
- Fe (1)
- Fe-Ni (1)
- Fe2TiO5 (1)
- Feinkornbaustahl (1)
- Ferritic spheroidal graphite cast iron (1)
- Ferritic steels (1)
- Ferritic–martensitic steel (1)
- Ferumoxytol (1)
- Festphasenextraktion (1)
- Feuerwehr (1)
- Fiber Bragg grating (FBG) (1)
- Fibres (1)
- Filtered back projection (1)
- Filters (1)
- Fine Powder (1)
- Fine-grained Steel (1)
- Fingerprint (1)
- Finite element analysis (1)
- Finite elements (1)
- Finite-element method (1)
- Fire (1)
- Fire damp (1)
- Flammability (1)
- Flammable Gas (1)
- Flammable Liquid (1)
- Flow Chemistry (1)
- Flow-system (1)
- Flowability (1)
- Fluid-flow (1)
- Fluorescence standard (1)
- Fluorescent label (1)
- Flüssigkeitssensor (1)
- Foaming (1)
- Focused Ion Beam (1)
- Force distance curve (1)
- Force distance curves (1)
- Force-distance diagram (1)
- Formation (1)
- Forschungsdatenmanagement (1)
- Forschungsstrategie (1)
- Four-point bending test (1)
- Fractography (1)
- Freeze Drying (1)
- Freeze casting (1)
- Fresnoit (1)
- Friction Stir Welding (1)
- Frozen state photopolymerization (1)
- Full penetration (1)
- Fully aromatic frameworks (1)
- Functionalization (1)
- Functionalized graphene (1)
- Functionalized nanographene (1)
- Fusion zone (1)
- Fügetechnologie (1)
- GMA welding (1)
- GMAW (1)
- GUM-compliance (1)
- Gadolinium (1)
- Gallium doping (1)
- Gamma (1)
- Gas Barrier Properties (1)
- Gas analytic (1)
- Gas permeability (1)
- Gas separation membranes (1)
- Geant4-DNA (1)
- Gefahrenklasse (1)
- Gefahrgruppen (1)
- Gefahrgutregeln (1)
- Gefahrstoffverordnung (1)
- Gefügeuntersuchung (1)
- Gelartige Elektolyte (1)
- Gelelektrolyte (1)
- Geology (1)
- Gesteinskorrosion (1)
- Ggraphene polymer nanocomposite (1)
- Glas (1)
- Glasmonolith (1)
- Glass ceramic (1)
- Glass paints (1)
- Glass powder (1)
- Glass scanning (1)
- Glass screening device (1)
- Gleichgewicht (1)
- Glucose (1)
- Glue (1)
- Gold Nanoparticle (1)
- Gold Nanoparticles (1)
- Gold nanoclusters (1)
- Grain boundary (1)
- Grain size (1)
- Grain structure (1)
- Graphene Oxide (1)
- Graphene polymer nanocomposite (1)
- Graphite modules (1)
- Grating (1)
- Grenzfläche als Material (1)
- Grinding (1)
- Grünfolieneigenschaften (1)
- HAZ (1)
- HDPE Soprption (1)
- HDPE Sorption (1)
- HPLC (1)
- HSLA (1)
- HVO (1)
- Halophile (1)
- Hamonisierung (1)
- Hard machining (1)
- Hardmetal (1)
- Hardness (1)
- Heat control (1)
- Heat saturation function (1)
- Heated concrete (1)
- Heating oil (1)
- Heating oil - biodiesel - blend (1)
- Heating oil tanks (1)
- Heating oil with 10 % FAME (1)
- Heating oil with 10% biodiesel (1)
- Heating oil with 20% biodiesel (1)
- Heating oil-Biodiesel-Blend (1)
- Heavy metal free (1)
- Heissrisse (1)
- Heizöl mit 10% Biodiesel (1)
- Heizöl mit 20 % Biodiesel (1)
- Heizöl mit 20% Biodiesel (B20) (1)
- Heizöl-FAME-Blends (1)
- Heißgaskorrosion (1)
- Heißrisse (1)
- Hierarchical porosities (1)
- High Molecular Polyethylene (1)
- High alloyed steel (1)
- High entropy alloys (1)
- High pressure (1)
- High specific surface area (1)
- High-power laser beam (1)
- High-temperature corrosion (1)
- High-temperature oxidation (1)
- High-voltage testing (1)
- Highspeed plasma (1)
- Hochentropielegierungen (1)
- Hochleistungslaserstrahlschweißen (1)
- Hot Cracking (1)
- Hot crack (1)
- Hot stamping (1)
- Human antibodies (1)
- Human umbilical cell adhesion (1)
- Hybrid components (1)
- Hybrid laser arc welding (1)
- Hybrider Werkstoffverbunde (1)
- Hydration (1)
- Hydrogel (1)
- Hydrogen Assisted Cracking (HAC) (1)
- Hydrogen Embrittlement (1)
- Hydrogen assisted stress corrosion cracking (1)
- Hydrogen dependent mechanical properties (1)
- Hydrogen diffusivity (1)
- Hydrogen methane (1)
- Hydrogen-containing hot gas (1)
- Hydrophobic interaction (1)
- Hydrophobin (1)
- Hydrothermal synthesis (1)
- Hydrothermale Calcinierung (1)
- Hygrothermal (1)
- Hyperbranched (1)
- Hysteresis measurement (1)
- Härte (1)
- IAEA fire (1)
- ICP-MS (1)
- IEQ (1)
- IIT (1)
- IR spectroscopy (1)
- ISO (1)
- ISO 14577 (1)
- ITS region (1)
- ImAFM (1)
- Imaging (1)
- Immobilisierung (1)
- Immobilization (1)
- Immunglobulin (1)
- Immunoaffinity extraction (1)
- Impact behaviour (1)
- Impact damage (1)
- Impedance spectroscopy (1)
- Implant test (1)
- Implant-test (1)
- Implants (1)
- Impurity segregation (1)
- In situ measurement, (1)
- In situ testing (1)
- In-Situ X-ray CT (1)
- In-situ Process Monitoring (1)
- Inclusion cluster (1)
- Inclusion size (1)
- Inconel 625 (1)
- Inconel 686 (1)
- Incremental lifetime models (1)
- Indenter modulus (1)
- Indonesien (1)
- Inertisierung (1)
- Inflammation (1)
- Infrared Thermography (1)
- Infrared nano AFM (1)
- Infrared spectroscopy (1)
- Infrared thermography (1)
- Initial crack size (1)
- Ink terminology (1)
- Inline NMR Spectroscopy (1)
- Innenraumluft (1)
- Insitu test (1)
- Institut Laue Langevin (1)
- Instrumented Indentation Testing (1)
- Instrumentierte Eindringprüfung (1)
- Instrumentierte Eindringprüfung (IIT) (1)
- Integrated Processes (1)
- Integrating sphere spectroscopy, (1)
- Inter-laborator comparison (1)
- Interdisciplinary (1)
- Interfaces (1)
- Interfacial forces (1)
- Intergranular cracking (1)
- Intermodulation (1)
- Intermodulation AFM (1)
- Intermodulation-AFM (1)
- Internal Surfaces (1)
- Internal oxidation (1)
- Introduction (1)
- Inverse Problems (1)
- Ionic porosity (1)
- Ions (1)
- Iron isotope fractionation (1)
- Iron meteorite (1)
- Iron oxide (1)
- Journal (1)
- Kabeltrenner (1)
- Kathodische Korrosionsschutz (1)
- Keramische Folien (1)
- Kieselsol (1)
- Kinetics (1)
- Klebeverbindungen (1)
- Knoevenagel condensation (1)
- Knotenweise Zwangsbedingungen (1)
- Kobaltlegierung (1)
- Kompaktierbarkeit (1)
- Kompressibilität (1)
- Konformitätsbewertung (1)
- Konformitätserklärung (1)
- Kontaktkorrosion (1)
- Korosi (1)
- Korrelationsmatrix (1)
- Korrosionsbeständigkeit (1)
- Korrosionsschnelltest (1)
- Korrosionsschäden (1)
- Korrosionsüberwachung (1)
- Korund (1)
- Kraftstoffabbau (1)
- Kraftstoffbehälter (1)
- Kreislaufwirtschaft (1)
- Kriechen (1)
- Kriechverhalten (1)
- Kristallisation (1)
- Kristallsystem (1)
- Kunststoff (1)
- Kunststoff und Röntgen-Rückstreuung (1)
- Kurz- und Langriss-Ermüdungsbruchmechanik (1)
- Kurzfaser-verstärkte Thermoplaste (1)
- Kurzrisswachstum (1)
- LC / MALDI-TOF-MS coupling (1)
- LC x ESI-TOF-MS (1)
- LC-MS (1)
- LCC (1)
- LCCC (1)
- LEVASIL 50/50 (1)
- LIBS (1)
- LL equation (1)
- LPBF (1)
- LT-FCM (1)
- LTCC multilayer (1)
- LTT filler material (1)
- LTT-Zusatzwerkstoff (1)
- La(Fe,Si)13 phase (1)
- Labelling (1)
- Lack-of-fusion (1)
- Lactide (1)
- Ladetankausrüstung (1)
- Laminates (1)
- Laminographie (1)
- Landau Lifshitz Gilbert equation (1)
- Large-pore (1)
- Laser Metal Deposition (LMD) (1)
- Laser Powder Bed Melting (1)
- Laser Scanning Microscopy (LSM) (1)
- Laser hybrid welding (1)
- Laser powder bed fusion (1)
- Laser processing (1)
- Laser surface texturing (1)
- Laser welding (1)
- Laser-Hybridschweißen (1)
- Laser-Pulver-Auftragschweißen (1)
- Laser-induced nanostructures (1)
- Laser-induced slip casting (1)
- Laser-modified surface (1)
- Laserauftragschweißen (1)
- Laserbearbeitung (1)
- Laserdispergieren (1)
- Laserpulverauftragschweißen (1)
- Laserscanningmikroskopie (LSM) (1)
- Laserstrahlhybridschweißen (1)
- Laserstrahlschmelzen im Pulverbett (1)
- Lattice structure (1)
- Layer system (1)
- Layer-by-layer deposition (1)
- Layerwise Slurry Deposition (1)
- Layerwise slurry deposition (1)
- Leaching of alkalis (1)
- Lead isotope composition (1)
- Lead-free (1)
- Leak-tightness (1)
- Lean duplex (1)
- Leather (1)
- Lebensdauer (1)
- Legierung (1)
- Legionella (1)
- Leichtbau (1)
- Levitation (1)
- Ligand (1)
- Linear polyglycerol (1)
- Liquid Crystals (1)
- Liquid crystals (1)
- Liquid metal embrittlement (1)
- Load history (1)
- Load partition (1)
- Local fatigue spproaches (1)
- Localized Laser Dispersing (1)
- Long-term storage (1)
- Low Reynolds number swimmers (1)
- Low Temperature Toughness (1)
- Low Transformation Temperature (1)
- Low cycle fatigue (1)
- Low heat input GMA welding (1)
- Low melting glasses (1)
- Low-tech approach (1)
- Lubrication (1)
- Luminescence (1)
- MAG (1)
- MALDI TOF MS (1)
- MALDI-TOF (1)
- MEMUS (1)
- MOF-74 (1)
- MPI (1)
- MPLS (1)
- Machine Learning (1)
- Macrophage (1)
- Magmatic and hydrothermal processes (1)
- Magnet coupling (1)
- Magnetic (1)
- Magnetic Nanoparticles (1)
- Magnetic anisotropy (1)
- Magnetic domains (1)
- Magnetic field (1)
- Magnetic interacion (1)
- Magnetic nanoparticle (1)
- Magnetic nanoparticles (1)
- Magnetic resonance imaging (1)
- Magnetic swimmers (1)
- Magnetische Domänen (1)
- Magnetization dynamics (1)
- Magnetocoloric (1)
- Magnetoelastic effect (1)
- Magnetoelastischer Effekt (1)
- Magnéli phase (1)
- Maintenance (1)
- Manual of Tests and Criteria (1)
- Market surveillance (1)
- Maskinteknik (1)
- Mass spectrometry of polymers (1)
- Mass transport (1)
- Massenspektrometrie (1)
- Masterbatch (1)
- Material characterization (1)
- Material defects (1)
- Materialien (1)
- Materialkreislauf (1)
- Materialprüfung (1)
- Measurement (1)
- Measurement uncertainty (1)
- Mechanical Engineering (1)
- Mechanical Properties (1)
- Mechanical behavior (1)
- Mechanical property (1)
- Medical implants (1)
- Medieval glasses (1)
- Mehr-Proben-Prüfverfahren (1)
- Mehrachsige Verformung (1)
- Melt pool behaviour (1)
- Melt-extraction technique (1)
- Mesoporous Silica (1)
- Mesoporous iridium-titanium mixed oxides (1)
- Mesoporous mixed metal oxide films (1)
- Messing (1)
- Messtechnik (1)
- Metal Matrix Composite (1)
- Metal carbides (1)
- Metal matrix composite (1)
- Metal organic framework (1)
- Metal phosphonates (1)
- Metal powder characterization (1)
- Metal reducing bacteria (1)
- Metal-organic-frameworks (1)
- Metalldichtung (1)
- Metallkorrosion (1)
- Metalls (1)
- Metallurgie (1)
- Methanogen (1)
- Method comparison (1)
- Method validation (1)
- Methos comparision (1)
- Micro-shrinkages (1)
- Microanalysis (1)
- Microarray (1)
- Microbeam analysis (1)
- Microbial (1)
- Microbially induced corrosion (1)
- Microbiologically Influrenced Corrosion (MIC) (1)
- Microencapsulation (1)
- Microparticle (1)
- Microparticles (1)
- Microplastic (1)
- Microstructural analysis (1)
- Microstructure Characterization (1)
- Microstructure analysis (1)
- Microstructure characterisation (1)
- Microstructure evolution (1)
- Microwave synthesis (1)
- Mikrostrukturuntersuchung (1)
- Milling (1)
- Mis-match (1)
- Mittelrippendefekt (1)
- Mixed-linkers (1)
- Modell der konstanten Flammentemperaturen (1)
- Modified Varestraint-/Transvarestraint test (1)
- Modular Production (1)
- Module (1)
- Moisture (1)
- Molecular mobility (1)
- Monitoring (1)
- Monte-Carlo (1)
- Mortar (1)
- Mortel (1)
- Moving mesh (1)
- Mueller-Matrix Ellipsometry (1)
- Multiaxial deformation (1)
- Multiphoton laser structuring (1)
- Multiple-layered scaffold (1)
- Multivariate data analysis (1)
- Museum insect pest (1)
- Mussel-inspired adhesives (1)
- NBR (1)
- NDT Monitoring (1)
- NIR dyes (1)
- NP (1)
- Nahtgeometrie (1)
- Nano particle (1)
- Nano screening (1)
- NanoValid (1)
- Nanocasting (1)
- Nanoconfinement (1)
- Nanocrystal (1)
- Nanohybrid (1)
- Nanoindentation (1)
- Nanokomposit (1)
- Nanomaterial Properties (1)
- Nanomechanical properties (1)
- Nanometrology (1)
- Nanoparticle Characterization (1)
- Nanoparticle characterization (1)
- Nanoparticle size measurement (1)
- Nanoparticular TiO2 (Anatase) (1)
- Nanoporous (1)
- Nanorods (1)
- Nanoscale (1)
- Nanosecond laser (1)
- Nanosecond laser irradiation (1)
- Nanostructure quantification (1)
- Nanotechnologie (1)
- Natural (1)
- NbC (1)
- Nd excitation (1)
- Neel wall (1)
- Neuartige Materialien (1)
- Neutron imaging (1)
- Neutronen Abschirmmaterial (1)
- Neutronenbeugung (1)
- Neutronenradiographie (1)
- Neutronentomographie (1)
- New standards (1)
- Next Generation Sequencing (1)
- Ni (1)
- Ni-Resist (1)
- Nicht-lineare Regression (1)
- Nickel (1)
- Nickel alloys (1)
- Nickellegierung (1)
- Niedrigenergie-Polymeren (1)
- Niobium alloying (1)
- Nitrene[2+1]cycloaddition (1)
- Nitride (1)
- Nitrides (1)
- Nitrieren (1)
- Nitrogen (1)
- Non-destructive Materials (1)
- Non-destructuve testing (1)
- Non-spherical shape (1)
- Nonclassical crystallization (1)
- Nosema ceranae (1)
- Notified bodies (1)
- Numerical Simulation (1)
- Numerical analysis (1)
- Numerical modelling (1)
- Numerische ISmulation (1)
- Numerische Simulation (1)
- OTDR (1)
- Oberfläche (1)
- Oberflächenanalytik (1)
- Oberflächenmesstechnik (1)
- Oberflächenpotential (1)
- Oberflächensteifigkeit (1)
- Oberflächentechnik (1)
- Oil and gas industry (1)
- Ooxidation (1)
- Optical Emission Spectroscopy (1)
- Optical assay (1)
- Optical criterion (1)
- Optical emission spectroscopy (1)
- Optical fiber sensor (1)
- Optical fibers (1)
- Optical measurment technique (1)
- Optical near field (1)
- Optical properties (1)
- Optical spectroscopy (1)
- Optical tomography (1)
- Optische Fasern (1)
- Optische Tomografie (1)
- Ordered mesoporous silica (1)
- Ore provenance (1)
- Organic–inorganic nanostructures (1)
- Orientation relationship (1)
- Oscillating magnetic field (1)
- Osmia bicornis (1)
- Outokumpu: Stainless steel (1)
- Oxidation protection (1)
- Oxocobaltates (1)
- Oxygen Evolution Catalyst (1)
- Oxygen evolution reaction (1)
- Oxygen evolution reaction (OER) (1)
- Oxygen permability (1)
- Oxygen reduction reaction (1)
- Oxygen sensitive (1)
- P25 (1)
- P92 (1)
- PC characterisation (1)
- PDT (1)
- PE-HD Sorption (1)
- PEAK (1)
- PH (1)
- PMMA (1)
- PTFE (1)
- PUR (1)
- Package (1)
- Package testing (1)
- Paint (1)
- Pair Distribution Functions (1)
- Papierasche (1)
- Parabolic flight (1)
- Paramagnetism (1)
- Parchment (1)
- Partial penetration laser hybrid welding (1)
- Particle (1)
- Particle accretion (1)
- Particle size (1)
- Partikelgrößenverteilung (1)
- Passivschicht (1)
- Path planning (1)
- Pathogen spillover (1)
- Pentaerythritol (1)
- Peptide (1)
- Peptide Library (1)
- Peptide mass fingerprinting (1)
- Peptides (1)
- Performance assessment (1)
- Performance test (1)
- Performance validation (1)
- Periodic inspections (1)
- Peritectic reaction (1)
- Permeability (1)
- Permitted explosives (1)
- Perovskite (1)
- Phage Display (1)
- Phase mask (1)
- Phase transition (1)
- Phase-field (1)
- Phase-field simulation (1)
- Phasenumwandlung (1)
- Phononic crystal (1)
- Phononische Kristalle (1)
- Phosphate (1)
- Phosphinine (1)
- Phosphonates (1)
- Phosphorus (1)
- Photocatalyst (1)
- Photocuring (1)
- Photogrammetry (1)
- Photoluminescence quantum yield (1)
- Photon Counting Detectors (1)
- Photon counting detectors (1)
- Photonenzählende Detektoren (1)
- Photooxidation (1)
- Photostability (1)
- Plasmon resonance (1)
- Plasmonic nanofocusing spectroscopy (1)
- Plastic deformation (1)
- Plastikstrategie (1)
- Platinum-group-metals (1)
- Polarisation (1)
- Polarization spectroscopy (1)
- Poly(N-vinylpyrrolidone) (1)
- Poly(vinyl chloride) (1)
- Polyamid 12 (1)
- Polycaprolactone (1)
- Polyethylen hoher Dichte (1)
- Polyethylene Glycol (1)
- Polymer Testing (1)
- Polymer aging (1)
- Polymer composites (1)
- Polymer optical fiber (1)
- Polymer particle (1)
- Polymer-based nanocomposites (1)
- Polymere Werkstoffe (1)
- Polymeric materials (1)
- Polymeric membrane (1)
- Polyphosphoester (1)
- Polypropylene (1)
- Polysaccharides (1)
- Pore size tailoring (1)
- Pore solution (1)
- Porosität (1)
- Porous ceramics (1)
- Porphyrin (1)
- Portland cement (1)
- Post-modification by L-cysteine (1)
- Potential (1)
- Potentiometry (1)
- Powder analysis (1)
- Practical aspects (1)
- Pre-standardisation (1)
- Preceramic polymer (1)
- Precipitation hardening (1)
- Precision polymer sequencing (1)
- Prediction (1)
- Pressure-assisted sintering (1)
- Pressverbindung (1)
- Prevention (1)
- Priam's treasure (1)
- Primär- und Sekundärspannungen (1)
- Process Analytical Technology (1)
- Process Monitoring (1)
- Process development (1)
- Process parameters (1)
- Processing window (1)
- Projection matrix (1)
- Projektmanagement (1)
- Propagation modes (1)
- Propane gas fire test facility (1)
- Properties (1)
- Protection (1)
- Protein (1)
- Proton cunductor (1)
- Prozessmanagement (1)
- Prozessmonitoring (1)
- Prozesssimulation (1)
- Prozessüberwachung (1)
- Prüftechnik (1)
- Pseudo peptides (1)
- Pulsed thermography (1)
- Pultruded fiber rods (1)
- Quality assurcance (1)
- Qualitätsmanagement (1)
- Quantum yields (1)
- Quinones (1)
- REACH (1)
- REM (1)
- RME (1)
- ROPPOC (1)
- RRT (1)
- Radiation damage (1)
- Radioactive NP (1)
- Radioactive material (1)
- Radioactive sources (1)
- Radiographie (1)
- Radiography (1)
- Radiological inspections (1)
- Raman microscopy (1)
- Rayleigh scattering (1)
- Reaction Monitoring (1)
- Real-time infrared spectroscopy (1)
- Reconstructed ion chromatograms (1)
- Recycling (1)
- Recycling-by-design (1)
- Reference Nanomaterials (1)
- Reference material (1)
- Reference methods (1)
- Reference particles (1)
- Referenzmaterial (1)
- Referenzorganismus (1)
- Referenzverfahren (1)
- Refraction (1)
- Regeneration (1)
- Regulation (1)
- Reinforcement (1)
- Relaxation fatigue (1)
- Repair patch (1)
- Representative material properties (1)
- Repräsentative Werkstoffeigenschaften (1)
- Residual Stresses (1)
- Residual stress analysis (1)
- Residual stressMultiphase compositesInteractionMicromechanical schemesAnisotropy (1)
- Resonance (1)
- Resonance testing (1)
- Restlebensdauer (1)
- Restoration and conservation (1)
- Reverse microemulsion (1)
- Rh-Ir alloys (1)
- Rheological properties (1)
- Rietveld (1)
- Ring-expansion polymerization (1)
- Ring-opening polymerization (1)
- Rissarrest (1)
- Risstrajektorie (1)
- Rod structure (1)
- Rohrprobekörper (1)
- Rosin (1)
- Rotorblatt (1)
- Round robin tests (1)
- Round-Robin-Tests (1)
- Rundnähte (1)
- Rührreibschweißen (1)
- SBFEM (1)
- SDC (1)
- SEC (1)
- SEM (1)
- SEM/EDS/STRATAGem (1)
- SIMS (1)
- SKPM (1)
- SRB (1)
- STEM (1)
- SWIR photoluminescence (1)
- Safety (1)
- Safety characteristics (1)
- Sailplane Development Panel (1)
- Salicylate (1)
- Salt melt (1)
- Samarium doped ceria (1)
- Sample preparation (1)
- Saure Hydrolyse (1)
- Scaffolds (1)
- Scaled Boundary Finite Element Method (1)
- Scanning Electron Microscopy (SEM) (1)
- Scanning electrochemical microscope (SECM) (1)
- Scanning transmission electron microscopy (1)
- Scattering (1)
- Scavenging effect of iron (1)
- Schadenstolerante Bauteilauslegung (1)
- Schallemmission (1)
- Schmiedeteile (1)
- Schmiermittel (1)
- Schwarzpulverähnliches Reinigungspulver (1)
- Schweißeigenspannungen (1)
- Schweißeigenspannungs-Tiefen-Profile (1)
- Schweißen von kaltzähen Stählen (1)
- Schweißstruktursimulation (1)
- Schädigungsverhalten (1)
- Science (1)
- Sciences (1)
- Scratches (1)
- Screening (1)
- Seal failure (1)
- Security (1)
- Segmentation (1)
- Selective Laser Melting (SLM) (1)
- Selective Laser Sintering (SLS) (1)
- Selektives Lasersintern (1)
- Self-assembly (1)
- Self-lubricating coating (1)
- Semi-metallic friction material (1)
- Semi-metallic sintered material (1)
- Semiconductor (1)
- Semiconductor materials (1)
- Sensitisation (1)
- Sensoren (1)
- Sequence-defined oligomer (1)
- Sequencing (1)
- Service life (1)
- Setting (1)
- Shale (1)
- Shape (1)
- Shape-controlled (1)
- Shear behavior (1)
- Shore Hardness (1)
- Shore-Härte (1)
- Short-distance diffusion (1)
- Shrinkage (1)
- Shrinkages (1)
- Si-Ge (1)
- SiO2 Nanoparticle (1)
- Sicherer Betrieb (1)
- Sicherheit (1)
- Sicherheitsdatenblatt (1)
- Silane (1)
- Silica (1)
- Silica coating (1)
- Silicoborate glasses (1)
- Silicon Carbide (1)
- Silver indium sulfide (1)
- SimCoLas (1)
- Single cell-ICP-ToF-MS (1)
- Single molecule (1)
- Single particle-ICP-ToF-MS (1)
- Single-dot spectroscopy (1)
- Single-source precursors (1)
- Singlet oxygen (1)
- Sintern (1)
- Size (1)
- Size distribution (1)
- Sliding wear (1)
- Slidng wear (1)
- Slow Crack Growth (SCG) (1)
- Slow crack growth (1)
- Small Angle Neutron Scattering (1)
- Small angle neutron scattering (1)
- Small-angle x-ray scattering (1)
- Soda-lime-silica (1)
- Sodium ion batteries (1)
- Soil (1)
- Soil incubation study (1)
- Sol-gel coating (1)
- Solidification Cracking (1)
- Solubilizer (1)
- Sonochemical synthesis (1)
- Sorption (1)
- Spaltkorrosion (1)
- Spannungsrelaxationsrisse (1)
- Spannungsriss (1)
- Spannungsrisskorrosion (1)
- Spar cap design (1)
- Spark plasma sintering (1)
- Speciation analysis (1)
- Specific Surface Area (BET) (1)
- Spectral irradiation (1)
- Spectroscopic Imaging (1)
- Spektrale Ellipsometrie (SE) (1)
- Spin (1)
- Spontaneous emulsification (1)
- Spring constant (1)
- Spring constant (1)
- SrTiO3 (1)
- Stabilität von Eigenspannungen (1)
- Stabilization (1)
- Stabstruktur (1)
- Stahl (1)
- Stahl und Aluminium (1)
- Stained glass (1)
- Stained glass windows (1)
- Stained glasses (1)
- Stand der Normung (1)
- Standardization of Ellipsometry (1)
- Stanzen (1)
- Static Mixing (1)
- Statistics (1)
- Stepwise growth (1)
- Stereocomplex (1)
- Stimuli-responsive polymers (1)
- Stochastic Landau Lifshitz equation (1)
- Stress analysis (1)
- Stress intensity factor (1)
- Stress-strain behavior (1)
- Structural analysis (1)
- Structural defects (1)
- Structural integrity (1)
- Structural safety (1)
- Structural sealant glazing (1)
- Structural steel (1)
- Structure-property relationship (1)
- Structured light scanning (1)
- Structures under extreme conditions (1)
- Struktur (1)
- Struvite (1)
- Sub-oxide (1)
- Subcritical crack growth (1)
- Substitution (1)
- Sulfur (1)
- Superalloy (1)
- Superconducting magnet (1)
- Supercritical CO2 (1)
- Supercritical/dense phase CO2 (1)
- Superimposed loading (1)
- Supermartensit (1)
- Supermartensitic Stainless Steel (SMSS) (1)
- Superparamagnetism (1)
- Surface Chemical Transformation (1)
- Surface Chemistry (1)
- Surface analysis (1)
- Surface characterization (1)
- Surface charge (1)
- Surface group (1)
- Surface group analysis (1)
- Surface group quantification (1)
- Surface roughness (1)
- Surface roughness analysis (1)
- Surface structures (1)
- Surfaces (1)
- Survey (1)
- Survival rates (1)
- Suzuki-Miyaura coupling (1)
- Swarming (1)
- Swept wavelength interferometry (1)
- Switch (1)
- Sychrotron tomography (1)
- Synchrotron CT (1)
- Synchrotron Energy Dispersive Diffraction (1)
- Synchrotron Röntgen Refraktion (1)
- Synchrotron X-ray diffraction (1)
- Synchrotron X-ray refraction radiography (1)
- Synchrotron X-ray tomography (1)
- Synchrotron X‐ray refraction radiography (1)
- Synchrotron computed tomography (1)
- Synchrotron radiation (1)
- Synchrotron x-ray refraction radiography (SXRR) (1)
- Synchrotronbeugung (1)
- TGA-FTIR (1)
- THz-TDS (1)
- TMF (1)
- TaC (1)
- Tafel Plot (1)
- Tankschifftyp (1)
- Tanning (1)
- Tantalum carbide (1)
- Tara Mediterranee (1)
- Technical crack detection (1)
- Technological innovation (1)
- Temperature effects (1)
- Temperature modulated differential scanning calorimetry (1)
- Temple Scroll (1)
- Tensile Stress (1)
- Tensile testing (1)
- Themral cycles (1)
- Therapeutic antibodies (1)
- Thermal analysis (1)
- Thermal arrier coatings (1)
- Thermal barrier coatings (1)
- Thermal conductivity device (1)
- Thermal expansion (1)
- Thermal extraction-desorption gas chromatography mass spectrometry (1)
- Thermal testing (1)
- Thermally-induced moisture transport (1)
- Thermische Belastung (1)
- Thermische Betriebsbelastungen (1)
- Thermische Dehnung (1)
- Thermo-fluid dynamics (1)
- Thermo-fluid flow (1)
- Thermo-responsive polymers (1)
- Thermodynamic analysis (1)
- Thermoelectric properties (1)
- Thermograhy (1)
- Thermogravimetry (1)
- Thermomechanics (1)
- Thermomechanik (1)
- Thermoplastic polyurethane (1)
- Thermoplastics (1)
- Thick materials (1)
- Thick shells (1)
- Thick-walled Structures (1)
- Thick-walled steel (1)
- Thick-walled steels (1)
- Thin film (1)
- Thin film systems (1)
- Thin magnetic films (1)
- Thiol-ene click chemistry (1)
- TiO2 (1)
- TiO2 nanoparticle (1)
- Time-gated emission (1)
- Time-resolved flow cytometry (1)
- Time-temperature superposition (1)
- Tin(II)octanoate (1)
- Titan-Halterung (1)
- Titanium dioxide (1)
- ToF-SIMS (1)
- Tomographie, (1)
- Tool steel (1)
- Topometry (1)
- Topotactic phase transitions (1)
- Torsional fatigue (1)
- Total scattering analysis (1)
- Toughness (1)
- Toxicity (1)
- Transformation pathways (1)
- Transient heat transfer (1)
- Transport und Lagerung von Chemikalien (1)
- Trastuzumab (1)
- Tribologische Datenbank (1)
- Tribologsches Charakterisierungsdienste (1)
- Trilobite compound eyes (1)
- Trinkwasserinstalltion (1)
- Triplet-triplet annihilation (1)
- Trojan silver artefacts (1)
- Tubular X-joints (1)
- Tuff (1)
- Tungsten-Rhenium (1)
- Tunnelatmosphöre (1)
- Two-Photon Polymerization (1)
- Two-dimensional hexagonal boron nitride(h-BN) (1)
- UCST polymers (1)
- UHMWPE (1)
- UN-Test O.3 (1)
- UV Vis (1)
- UV Weathering (1)
- UV-Bestrahlungsstärke (1)
- UV/VIS spectroscopy (1)
- Ultra-high strength steel (1)
- Ultrafast scattering (1)
- Ultraschallmessung (1)
- Ultraschallsensor (1)
- Ultraschallwellen (1)
- Ultrashort laser pulses (1)
- Ultrasonic measurement (1)
- Ultrasound (1)
- Uncertainty budget (1)
- Uncertainty budgets (1)
- Ungleichgewicht (1)
- Uniaxial compression tests (1)
- Unlegierter Baustahl (1)
- UpConversion (1)
- Upconverstion (1)
- VM12 SHC (1)
- Vacuum (1)
- Vacuum hot extraction (1)
- Varestraint (1)
- Verfleckungen (1)
- Vernetzung (1)
- Verschleiß (1)
- Verwitterung (1)
- Vickers (1)
- Vickers indentation (1)
- Viscoelastic model (1)
- Viscoplastic (1)
- Viscoplasticity (1)
- Viscous sintering (1)
- Viskosität (1)
- Vitual computer tomography simulation (1)
- Vorgehensweise (1)
- Vorhaben (1)
- WAXS (1)
- Warmfester Stahl (1)
- Wartung (1)
- Wasser (1)
- Wasserstoffspeicher (1)
- Wastewater (1)
- Water migration (1)
- Weathering resistance (1)
- Weißlichtinterferenzmikroskopie (WLIM, 3D) (1)
- Weld pool (1)
- Welding process simulation (1)
- Werkstoffauswahl (1)
- Werkstoffe (1)
- Werkstoffmechanische Prüfung (1)
- Wetting (1)
- White light interference microscopy(WLIM) (1)
- Wiederkehrende Prüfung (1)
- Wild bees (1)
- Wind rotor blade (1)
- Wirbelstrom (1)
- Wirbesltrom (1)
- Wood materials (1)
- X-ray (1)
- X-ray Absorption Spectroscopy (1)
- X-ray Photoelectron Spectroscopy (XPS) (1)
- X-ray absorption spectroscopy (1)
- X-ray imaging (1)
- X-ray microspectroscopy (1)
- X-ray spectroscopic techniques (1)
- X-ray spectroscopy (1)
- X8Ni9 (1)
- XAFS (1)
- XANES (1)
- Yb(III) complex (1)
- Year in Review (1)
- Young's modulus (1)
- Young´s modulus (1)
- Zement (1)
- Zeolitic Imidazolate Frameworks (1)
- Zeta potential (1)
- ZfP (1)
- Zinc (1)
- Zinc oxide (1)
- ZnO (1)
- Zug-Druck-Schubprüfung (1)
- Zugprüfungen (1)
- abtragende Glasbearbeitung (1)
- alumina (1)
- anion-exchange (1)
- antibody (1)
- arbidic austempered ductile iron (1)
- arbon capture (1)
- attraktive Wechelwirkung (1)
- bacteria (1)
- bacteria detection (1)
- beta particle (1)
- bioactive (1)
- biokompatibel (1)
- biomaterials (1)
- bone (1)
- carbon steel (1)
- ceramics (1)
- clustered nanoparticles (1)
- condensate (1)
- copper (1)
- degradation (1)
- deposition welding (1)
- dielectric spectroscopy (1)
- digital image correlation (1)
- dual phase steel (1)
- electrochemical characterization (1)
- ethylene vinyl acetate (1)
- fatigue crack growth (1)
- flow cytometry (1)
- fluorescence microscopy (1)
- gamma ray (1)
- gas separation membranes (1)
- geothermal energy (1)
- gesintert (1)
- high pressure (1)
- highspeed plasma laser cladding (1)
- i-Tribomat (1)
- immunoseparation (1)
- impurities (1)
- infrared spectroscopy (1)
- leakage (1)
- lifetime (1)
- magnetic nanoparticle (1)
- mechanical properties (1)
- method (1)
- microstructure analysis (1)
- molecular mobility (1)
- nanoindentation (1)
- nanoparticle (1)
- natural ventilation (1)
- pH (1)
- particle (1)
- performance test (1)
- phosphate glasses (1)
- pitting corrosion (1)
- polymers (1)
- polymers of intrinsic microporosity (1)
- polynorbornenes (1)
- product specification (1)
- quantum dot (1)
- quantum yield (1)
- radiolysis (1)
- resistance spot welding (1)
- rubber (1)
- screening tes (1)
- selective laser melting (1)
- shape control (1)
- single cell-ICP-ToF-MS (1)
- single particle-ICP-ToF-MS (1)
- steel (1)
- temeprature dependent exchange length (1)
- uncertainty (1)
- utilization, and storage (CCUS) technology (1)
- volume resistivity (1)
- water speciation (1)
- µ-XRF (1)
- Äquivalente Wärmequelle (1)
- μCT (1)
- кратер шва (1)
- кристаллизация, (1)
- плавление, (1)
- сварочная ванна (1)
- температурное поле (1)
- функция теплонасыщения (1)
Organisationseinheit der BAM
- 6 Materialchemie (229)
- 9 Komponentensicherheit (215)
- 7 Bauwerkssicherheit (164)
- 8 Zerstörungsfreie Prüfung (164)
- 5 Werkstofftechnik (161)
- 9.3 Schweißtechnische Fertigungsverfahren (118)
- 7.6 Korrosion und Korrosionsschutz (96)
- 8.5 Röntgenbildgebung (84)
- 6.6 Physik und chemische Analytik der Polymere (70)
- 1 Analytische Chemie; Referenzmaterialien (68)
Eingeladener Vortrag
- nein (443)
A selected series of dipole functionalized triphenylene-based discotic liquid crystals (DLCs) was synthesized and investigated in a systematic way to reveal the phase behavior and molecular dynamics. The later point is of particular importance to understand the charge transport in such systems which is the key property for their applications such as organic field-effect transistors, solar cells or as nanowires in molecular electronics, and also to tune the properties of DLCs. The mesomorphic properties were studied by polarizing optical microscopy, X-ray diffraction, and differential scanning calorimetry, which were compared to the corresponding unfunctionalized DLC. The molecular dynamics were investigated by a combination of state-of-the-art broadband dielectric spectroscopy (BDS) and advanced calorimetry such as fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS). Besides localized fluctuations, surprisingly multiple glassy dynamics were detected for all materials for the first time. Glassy dynamics were proven for both processes unambiguously due to the extraordinary broad frequency range covered. The a1-process is attributed to fluctuations of the alky chains in the intercolumnar space because a polyethylene-like glassy dynamics is observed. This corresponds to a glass transition in a confined three-dimensional space. The a2-process found at temperatures lower than a1-process, is assigned to small scale rotational and/or translational in plane fluctuations of the triphenylene core inside distorted columns. This can be considered as a glass transition in a one-dimensional fluid. Therefore, obtained results are of general importance to understand the glass transition, which is an unsolved problem of condensed matter science.
In this study, the molecular dynamics of a series of dipole functionalized triphenylene-based discotics, forming a columnar mesophase, were investigated by broadband dielectric spectroscopy (BDS). In addition to conductivity and localized dynamics, glassy dynamics were also observed. At higher temperatures an α1-processes and at low temperatures an α2 processes were detected having a completely different temperature dependence of its relaxation times. Different molecular assignments of α1- and α2-processes are suggested. The phase behavior of the material was explored under helium purge down to 100 K by differential scanning calorimetry (DSC). Besides the phase transition temperatures and enthalpies, one or two thermal glass transitions were found for all the materials. Moreover, the glassy dynamics were further investigated by Flash DSC, which is a chip-based calorimetry technique allowing for fast heating and cooling rates as high as 10000K/s.
Non-linear optical emitters are promising materials for energy applications and biotechnologies. Solid-state multi-band emitters like lanthanide doped up-conversion nanoparticles (UCNPs) show excellent photostability, are excitable in the near infrared (NIR), and show emission bands from the UV to SWIR spectral regions. The optical properties of these materials strongly depend on the excitation power density, i.e., the number of photons absorbed per time interval. The upconversion (ΦUC) and downshifting quantum efficiencies (ΦDS) of these materials, the excitation power dependent population, and the deactivation dynamics are influenced by nanoparticle architecture, doping concentration, and the microenvironment. We studied the fundamental changes of the luminescence properties of ß-NaYF4 UCNPs doped with Yb3+ and Er3+ depending on size, different surroundings such as aqueous and organic media, and different surface chemistries. We obtained further insights into shelling procedures, FRET optimization, influence of doping concentration, and advantages of different sensitizer ions.
Self-mated magnesia stabilized zirconia (Mg-PSZ) ceramic sliding couples have been investigated at 100 N load (P0max= 1324 MPa) in oscillating sliding conditions in different humidity conditions in air and in hot steam. Temperatures have been varied up to 400 °C and pressures up to 6 bars. The results show that the wear behavior of MgO-ZrO2 under high Hertzian contact pressures is strongly dependent on temperature and is similar for both dry oscillating and oscillating in hot steam. However, although the evolution in wear rates on temperature is similar and the wear rates of MgO-ZrO2 plunged above 300 °C in hot steam and air by nearly three orders of magnitude, SEM micrographs revealed in hot steam at 400 °C smooth wear tracks. In contrast, hot steam enhanced the tribochemistry of self-mated alumina couples and reduced wear rates. Hot steam decreased the coefficients of friction of MgO-ZrO2 with increasing temperature, but not the wear rates.
The Measurement- and Model-based Structural Analysis (MeMoS) integrates a finite element model into least squares adjustment and thus allows to evaluate a mechanical model and measurements in a combined analysis. To examine the capability to detect and localise damage using this integrated analysis MeMoS, a small-scale truss bridge made of aluminium profiles is built as a test specimen for this purpose.
By means of a small-scale truss bridge, the ability of the Measurement- and Model-based Structural Analysis to detect and localize damage was examined. Although there was no noteworthy difficulty in detecting damage, it turned out that damage localization responds sensitively to systematic influences, i.e. non-modelled properties of the mechanical model. Therefore, another experiment is being conducted to re-examine the Measurement- and Model-based Structural Analysis. For this purpose, the bending test is carried out as it has been already theoretically respectively numerically discussed. In this attempt, the systematic influences such as residual stress are kept as low as possible.
The present work is intended to make a contribution to the monitoring of civil engineering structures. The detection of damage to structures is based on the evaluation of spatially and temporally distributed hybrid measurements. The acquired data can be evaluated purely geometrically or physically. It is preferable to do the latter, since the cause of damage can be determined by means of geometrical-physical laws in order to be able to intervene in time and ensure the further use of the structures. For this reason, the continuum mechanical field equations in conjunction with the finite element method and hybrid measurements are combined into a single evaluation method by the adjustment calculation. This results in two challenges.
The first task deals with the relationship between the finite element method and the method of least squares. The finite element method solves certain problem classes, which are described by a system of elliptical partial differential equations. Whereas the method of least squares solves another class of problems, which is formulated as an overdetermined system of equations. The striking similarity between both methods is known since many decades. However, it remains unresolved why this resemblance exists. The contribution is to clarify this by examining the variational calculus, especially with regard to its methodological procedure. Although the well-known Gauss-Markov model within the method of least squares and the finite element method solve inherently different problem classes, it is shown that both methods can be derived by following the same methodological steps of the variational calculus. From a methodical viewpoint, this implies that both methods are not only similar, but actually the same. In addition, it is pointed out where a possible cross-connection to other methods exists.
The second task introduces a Measurement- and Model-based Structural Analysis (MeMoS) by integrating the finite element method into the adjustment calculation. It is shown in numerical examinations how this integrated analysis can be used for parameter identification of simple as well as arbitrarily shaped structural components. Based on this, it is examined with which observation types, with which precision and at which location of the structure these measurements must be carried out in order to determine the material parameters as precisely as possible. This serves to determine an optimal and economic measurement set-up. With this integrated analysis, a substitute model of a geometrically complex structure can also be determined. The issue of the detection and localisation of damage within a structure is studied by means of this structural analysis. The Measurement and Model-based Structural Analysis is validated using two different test setups, an aluminum model bridge and a bending beam.
The present work is intended to make a contribution to the monitoring of civil engineering structures. The detection of damage to structures is based on the evaluation of spatially and temporally distributed hybrid measurements. The acquired data can be evaluated purely geometrically or physically. It is preferable to do the latter, since the cause of damage can be determined by means of geometrical-physical laws in order to be able to intervene in time and ensure the further use of the structures. For this reason, the continuum mechanical field equations in conjunction with the finite element method and hybrid measurements are combined into a single evaluation method by the adjustment calculation. This results in two challenges.
The first task deals with the relationship between the finite element method and the method of least squares. The finite element method solves certain problem classes, which are described by a system of elliptical partial differential equations. Whereas the method of least squares solves another class of problems, which is formulated as an overdetermined system of equations. The striking similarity between both methods is known since many decades. However, it remains unresolved why this resemblance exists. The contribution is to clarify this by examining the variational calculus, especially with regard to its methodological procedure. Although the well-known Gauss-Markov model within the method of least squares and the finite element method solve inherently different problem classes, it is shown that both methods can be derived by following the same methodological steps of the variational calculus. From a methodical viewpoint, this implies that both methods are not only similar, but actually the same. In addition, it is pointed out where a possible cross-connection to other methods exists.
The second task introduces a Measurement- and Model-based Structural Analysis (MeMoS) by integrating the finite element method into the adjustment calculation. It is shown in numerical examinations how this integrated analysis can be used for parameter identification of simple as well as arbitrarily shaped structural components. Based on this, it is examined with which observation types, with which precision and at which location of the structure these measurements must be carried out in order to determine the material parameters as precisely as possible. This serves to determine an optimal and economic measurement set-up. With this integrated analysis, a substitute model of a geometrically complex structure can also be determined. The issue of the detection and localisation of damage within a structure is studied by means of this structural analysis. The Measurement and Model-based Structural Analysis is validated using two different test setups, an aluminum model bridge and a bending beam.
In the present work it was shown that the tribologcal profiles of special model oxides under dry unidirectional sliding have shown, that sub-oxides have a contribution to the tribological behavior of carbides and cermets, when they are tribo-oxidatively formed, because their tribological profiles as monolithic materials are homologous in part or totally, or compete with hardmetals or cermets, depending from the operating conditions regarded.
Das Seminar gibt einen detaillierten Einblick in die physikalischen Gefahrenklassen nach der CLP-Verordnung und stellt Strategien bei der Einstufung vor. Möglichkeiten zum Waiving und Screening werden erläutert und Berechnungsmethoden für Gemische werden in kurzen Aufgaben für die Seminarteilnehmer durchexerziert.
Der Vortrag gibt einen Überblick über das Chemikalienrecht, stellt die wichtigsten Regelungen sowie ihre Schnittstellen vor und gibt Informationen zu verfügbaren Hilfestellungen. Besprochen werden
• das UN-GHS (Globally Harmonized System of Classification and Labelling of Chemicals)
• REACH (EU-Verordnung zur Registrierung, Bewertung, Zulassung und Beschränkung chemischer Stoffe)
• CLP (EU-Verordnung über die Einstufung, Kennzeichnung und Verpackung von Stoffen und Gemischen)
• Gefahrstoffverordnung
Im Januar 2018 wurde die DIN EN 16516 „Bauprodukte: Bewertung der Freisetzung gefährlicher Stoffe – Bestimmung von Emissionen in die Innenraumluft“ als harmonisierte europäische Prüfnorm veröffentlicht. Für die Etablierung der DIN EN 16516 als neue Referenznorm wurden verschiedene Emissionsprüfungen mit dem Ziel durchgeführt, ein neues Prüfverfahren für Formaldehydemissionen aus Holzwerkstoffen zu erarbeiten. Das übergeordnete Ziel ist die Minimierung des Risikos von Überschreitungen des Innenraumrichtwertes für Formaldehyd. Die Untersuchungen ergaben teilweise hohe Formaldehydemissionen, insbesondere bei höheren Beladungsfaktoren und Temperaturen, sowie bei niedrigen Luftwechselraten. Eine getestete Spanplatte hätte aufgrund ihrer hohen Formaldehydemission nicht auf den deutschen Markt gebracht werden dürfen. Durch vergleichende Untersuchungen konnte ein Umrechnungsfaktor in Höhe von 2,0 für die Umrechnung von Prüfwerten nach DIN EN 717-1 zu DIN EN 16516 abgeleitet werden.
Die von der BAM eingekauften Holzwerkstoffplatten (Verlegespanplatten, OSB, Multiplexplatten) verschiedener Hersteller zeigten teilweise hohe Formaldehyd-emissionen unter den Prüfbedingungen nach EN 16516, eine Spanplatte hielt den Grenzwert von 0,1 ppm selbst bei Prüfung nach DIN EN 717-1 nicht ein, dürfte also in Deutschland gar nicht in den Verkauf gelangen.
Holzwerkstoffe, die unter den Prüfbedingungen der DIN EN 717-1 die Formaldehydklasse E1 einhalten, können insbesondere bei großflächigem Einsatz im Innenraum zu Überschreitungen des Richtwertes für die Innenraumluft führen. Zusätzlich zur Anpassung des Luftwechsels ist auch der Parameter Beladung bei einer Überarbeitung der Norm anzupassen. In der DIN EN 16516 werden produktspezifische (am Einsatz der Produkte orientierte) Beladungsfaktoren vorgegeben. Für den Einsatz von Holzwerkstoffplatten ergäben sich Beladungen von 0,4 (Boden oder Decke), 1,0 (Wände), 1,4 (Wände plus Boden oder Decke) und 1,8 m²/m³ (Wände, Boden und Decke). Um die realen Bedingungen in modernen Gebäuden abzubilden, ist deshalb eine Beladung von 1,8 m²/m³ für die Prüfkammermessung erforderlich. Hierbei ist darauf hinzuweisen, dass für die Beladung im Referenzraum Möbel nicht berücksichtigt wurden.
Damit soll sichergestellt werden, dass die Einhaltung des Schutzniveaus bei realen Innenraumbedingungen auch unter den Randbedingungen eines niedrigen Luftwechsels sowie bei sommerlichen Bedingungen und heutigem Lüftungsverhalten der Menschen soweit wie möglich gewährleistet ist.
Quality Aspects of Additively Manufactured Medical Implants - Defect Detection in Lattice Parts
(2019)
Additive Manufacturing technologies are developing fast to enable a rapid and flexible production of parts. Tailoring products to individual needs is a big advantage of this technology, which makes it of special interest for the medical device industry and the direct manufacturing of final products. Due to the fast development, standards to assure reliability of the AM process and quality of the printed products are often lacking. The EU project Metrology for Additively Manufactured Medical Implants (MetAMMI) is aiming to fill this gap by investigating alternative and cost efficient non-destructive measurement methods.
Yb,Nd,Er-doped upconversion nanoparticles (UCNPs) have attracted considerable interest as luminescent reporters for bioimaging, sensing, energy conversion/shaping, and anticounterfeiting due to their capability to convert multiple near-infrared (NIR) photons into shorter wavelength ultraviolet, visible or NIR luminescence by successive absorption of two or more NIR photons. This enables optical measurements in complex media with very little background and high penetration depths for bioimaging. The use of Nd3+ as substitute for the commonly employed sensitizer Yb3+ or in combination with Yb3+ shifts the excitation wavelength from about 980 nm, where the absorption of water can weaken upconversion luminescence, to about 800 nm, and laser-induced local overheating effects in cells, tissue, and live animal studies can be minimized. To systematically investigate the potential of Nd3+ doping, we assessed the performance of a set of similarly sized Yb3+,Nd3+,Er3+-doped core- and core–shell UCNPs of different particle architecture in water at broadly varied excitation power densities (P) with steady state and time-resolved fluorometry for excitation at 980 nm and 808 nm. As a measure for UCNPs performance, the P-dependent upconversion quantum yield (Φ) and its saturation behavior were used as well as particle brightness (B). Based upon spectroscopic measurements at both excitation wavelengths in water and in a lipid phantom and B-based calculations of signal size at different penetration depths, conditions under which excitation at 808 nm is advantageous are derived and parameters for the further optimization of triple-doped UCNPs are given.
The present study deals with the experimental characterization of short crack propagation in SLM (selective-laser-melting) manufactured stainless steel. More specifically, the determination of cyclic R-curves is discussed. This describes the dependency of the crack propagation threshold on crack growth during the short crack propagation stage. For metals, the threshold, starting at a material-intrinsic value, increases until it reaches a value independent of the crack length due to crack closure phenomena which build up at that stage. The cyclic R-curve, when used in the frame of a cyclic R curve analysis, characterizes the resistance of a material to fatigue crack growth and the ability to arrest a physically short crack. Thus, it is the link between classical fatigue and fracture mechanics. In the high-cycle-fatigue range, the short crack propagation stage dominates the overall lifetime, i.e., the number of cycles until failure. Below the fatigue limit crack arrest of hitherto propagable micro-cracks will occur. The effort for the experimental characterization of the short fatigue crack propagation behavior and the cyclic R-curve is very high compared to experiments on long crack propagation. A very exact measurement of crack extension is required, since small increments need to be depicted. Pre-cracking must leave a closure free initial crack, since closure must be build up only by the cyclic R-curve. The closure-free status is achieved by compression pre-cracking. The aim of the present study is an insight into the influence of an AM process on the short crack propagation threshold. Cyclic R-curves are experimentally determined at different load-ratios for 316L austenitic steel specimens produced by SLM and conventional manufacturing. Residual stresses are measured in the crack plane and their influence on the cyclic R-curve is discussed.
The present study deals with the experimental characterization of short crack propagation in SLM (selective-laser-melting) manufactured stainless steel. More specifically, the determination of cyclic R-curves is discussed. This describes the dependency of the crack propagation threshold on crack growth during the short crack propagation stage. For metals, the threshold, starting at a material-intrinsic value, increases until it reaches a value independent of the crack length due to crack closure phenomena which build up at that stage. The cyclic R-curve, when used in the frame of a cyclic R curve analysis, characterizes the resistance of a material to fatigue crack growth and the ability to arrest a physically short crack. Thus, it is the link between classical fatigue and fracture mechanics. In the high-cycle-fatigue range, the short crack propagation stage dominates the overall lifetime, i.e., the number of cycles until failure. Below the fatigue limit crack arrest of hitherto propagable micro-cracks will occur. The effort for the experimental characterization of the short fatigue crack propagation behavior and the cyclic R-curve is very high compared to experiments on long crack propagation. A very exact measurement of crack extension is required, since small increments need to be depicted. Pre-cracking must leave a closure free initial crack, since closure must be build up only by the cyclic R-curve. The closure-free status is achieved by compression pre-cracking. The aim of the present study is an insight into the influence of an AM process on the short crack propagation threshold. Cyclic R-curves are experimentally determined at different load-ratios for 316L austenitic steel specimens produced by SLM and conventional manufacturing. Residual stresses are measured in the crack plane and their influence on the cyclic R-curve is discussed.
The assessment of high cycle fatigue in additive manufactured (AM) components is a challenge due to complex microstructure, anisotropic material behavior, residual stresses and porosity / lack-of-fusion defects. Due to the statistical distribution of defects, a high scatter band of S-N-curves is expected. The fracture mechanics-based fatigue assessment of additive manufactured components must consider the propagation of short cracks emanating from defects.
In this work, the fatigue crack propagation resistance in the short and large crack regimes of additive and conventionally manufactured AISI 316L stainless steel is examined experimentally based on the cyclic R-curve. However, remaining residual stresses in the AM specimen lead to unexpected and dramatic crack-growth during the pre-cracking procedure.
Für Bauteile (Komponenten) von Versorgungsanlagen für flüssige Brenn- und Kraftstoffe muss die Beständigkeit der metallenen Werkstoffe und Polymere nachgewiesen werden. Im Anwendungsfall von Heizöl mit 20 % biogenen Anteilen in Form von Rapsölfettsäuremethylester (FAME, Biodiesel) ist es für eine konservative Beurteilung des Korrosionssystems Werkstoff/Medium/Umgebung wichtig, die Alterungseffekte des Mediums einzubeziehen.
Entwicklung eines Prüfverfahrens für die Untersuchung der Beständigkeit von metallenen Werkstoffen und Polymeren in Heizöl und Heizöl-FAME-Blends, das für eine Vorauswahl der Werkstoffe und zum Nachweis der Beständigkeit im Hinblick auf die bauaufsichtlichen Zulassungsverfahren geeignet ist. Ein Schwerpunkt wird bei den metallenen Werkstoffen auf der Erprobung von Messmethoden liegen, mit denen sich in kurzer Versuchszeit ein Korrosionsangriff detektieren lässt.
Metallene Werkstoffe:
Weder örtliche Korrosion noch erhöhte Flächenkorrosion (Korrosionsrate:< 0,1 m/Jahr) sind bei den bisher geprüften Werkstoffen: Aluminium,
C-Stahl 1.0037, austenitischer CrNi-Stahl 1.4301, Kupfer und Messing in Heizöl und B20 (Heizöl mit 20% Biodiesel) aufgetreten. Diese Werkstoffe sind in den Prüfmedien Heizöl und B20 als beständig zu bewerten.
Es wurde keine signifikante Veränderung des pH-Wertes der Prüfmedien gemessen.
Polymere:
Massebestimmung:
Die Prüfkörper der Elastomere ACM, HNBR und PUR sowie in geringerem Maße PE neigten zur Quellung in Heizöl und B20 nach 42 d und 84 d Auslagerung; für PA 6, POM und PVC wurde keine Masseänderung gemessen. Die Masseänderung der Prüfkörper in Heizöl und B20 ist mit Ausnahme von PUR vergleichbar. Bei PE traten Verfärbungen durch die Brennstoffe auf.
Zugeigenschaften:
ACM, HNBR, PE und PVC sind in Heizöl und B20 beständig, da die Änderung der Zugfestigkeit und der Reißdehnung < 15 % beträgt. PA und POM sind bedingt beständig, da die Änderung der Zugfestigkeit und der Reißdehnung < 30% beträgt.
Für Bauteile (Komponenten) von Versorgungsanlagen für flüssige Brenn- und Kraftstoffe muss die Beständigkeit der metallenen Werkstoffe und Polymere nachgewiesen werden. Im Anwendungsfall von Heizöl mit 20 % biogenen Anteilen in Form von Rapsölfettsäuremethylester (FAME, Biodiesel) ist es für eine konservative Beurteilung des Korrosionssystems Werkstoff/Medium/Umgebung wichtig, die Alterungseffekte des Mediums einzubeziehen.
Entwicklung eines Prüfverfahrens für die Untersuchung der Beständigkeit von metallenen Werkstoffen und Polymeren in Heizöl und Heizöl-FAME-Blends, das für eine Vorauswahl der Werkstoffe und zum Nachweis der Beständigkeit im Hinblick auf die bauaufsichtlichen Zulassungsverfahren geeignet ist. Ein Schwerpunkt wird bei den metallenen Werkstoffen auf der Erprobung von Messmethoden liegen, mit denen sich in kurzer Versuchszeit ein Korrosionsangriff detektieren lässt.
Die untersuchten Werkstoffe Aluminium, Stahl 1.0037, 1.4301, Kupfer, Messing (CuZn40Pb) und Zink (ZP0410) sind in B0, B20, B100 und in 6 Jahre altem B100 beständig.
Auch in einem Jahr alten B20 und in einem Jahr alten B100 sind die Werkstoffe beständig.
Bei Kupfer blieb die Korrosionsrate in der Flüssigphase sowohl in B20 (0 μ m/ a) als auch in B100 (4 μ m/ a) nach einem Jahr unverändert. Für das 6 Jahre alte B100 stieg die Korrosionsrate des Kupfers an (16 μ m/a). Im Gegensatz dazu sank bei Messing die Korrosionsrate in der Flüssigphase mit dem Alter des Brennstoffs, nach einem Jahr für B20 von 4 μ m/ a auf 1 μ m/a und für B100 von 36 μ m/ a auf 6 μ m/ a, im 6 Jahre alten B100 lag die Korrosionsrate des Messings bei 0 μ m/ a.
In 8 Jahre altem B10 trat bei Zink in der Flüssigphase Flächenkorrosion auf, es ist in dem Medium demnach nicht beständig. Messing zeigte örtliche Korrosion in der Gasphase, es ist folglich unbeständig und für den Einsatz in stark gealterten B10 nicht geeignet.
Aluminium, 1.0037, 1.4301 und Kupfer sind in dem 8 Jahre alten B10 beständig.
Die Änderung der Zugfestigkeit und der Reißdehnung von ACM, HNBR und FKM in Heizöl, B20 und gealterten B10 beträgt < 15 %. Diese Werkstoffe sind in Heizöl, B20 und in gealterten B10 unter Berücksichtigung des von der BAM zur Beurteilung der Beständigkeit festgelegten Grenzwertes von 15 % bei 40 °C als beständig zu bewerten.
PUR ist bei 40 °C nicht beständig in B20 und in gealtertem B10. Bei 70 °C ist HNBR nicht in B20 beständig aufgrund der Verringerung der Zugfestigkeit (40 %) und der Reißdehnung (50 %). FKM ist bei 70 °C in Heizöl und in B20 beständig.
Compatibility of polymeric materials with heating oil/biodiesel blends at different temperatures
(2019)
Materials compatibility is a major concern whenever the fuel composition is changed. The question arises of whether polymeric materials are resistant to heating oil with admixtures of 10 % biodiesel (B10) and 20 % biodiesel (B20).
The polarity of biodiesel increases its solvency and facilitates permeation and extrac-tion. Solvation, swelling and/or extraction lead to changes in the physical properties and chemical changes of polymeric materials.
The objective of this research was to determine the resistance of frequently used sealing materials such as FKM, EPDM, CR, CSM, NBR, IIR, VMQ, FVMQ, PA and PUR in up to four-year aged B10 for 84 days at 20 °C, 40 °C and 70 °C.
The polymeric materials: ACM, FKM, HNBR, PA, PE; POM, PUR and PVC were ex-posed to B20 for 84 days at 40°C and 70°C in another research project.
Mass, tensile strength, breaking elongation and Shore hardness A (D) of the test specimens were determined before and after the exposure for 84 (42) days in the heating oil blends B10 and B20.
There is not determined a threshold for the reduction in tensile properties and Shore hardness in the international standards. Therefore, a threshold of 15 % was deter-mined for the evaluation of the compatibility.
Measurements of the variations in mass, tensile properties and Shore hardness after exposure of the polymers in non-aged and aged heating oil B10 showed clearly that FKM, FVMQ and PA were the most resistant materials in B10. The elastomers CR, CSM, EPDM, IIR, NBR and VMQ were generally not resistant to B10. Damage to the materials increased with higher test temperatures and the age of B10.
FKM, POM and PVC showed high compatibility in B20 at 40°C and 70 °C. ACM, HNBR and PA were evaluated as resistant in B20 at 40 °C but not at 70°C.
Biofuels including ethanol and biodiesel (fatty acid methyl ester, FAME) represent an important renewable fuel alternative to petroleum-derived transport fuels. Increasing biofuels use would bring some benefits, such as a reduction in oil demands and greenhouse gas emissions, and an improvement in air quality. Materials compatibility is a major concern whenever the fuel composition is changed in a fuel system.
The objective of this research was to determine the resistance of frequently used sealing materials such as CR (chloroprene rubber), CSM (chlorosulfonated polyethylene), EPDM (ethylene-propylene-diene rubber), FKM (fluorocarbon rubber), FVMQ (methyl-fluorosilicone rubber), IIR (butyl rubber), NBR (acrylonitrile-butadiene rubber), PA (polyamides), PUR (polyester urethane rubber) and VMQ (methyl-vinyl-silicone rubber), in heating oil with admixtures of biogenic sources such as E10 (fuel with max. 10 % ethanol), E85 (fuel with 85 % ethanol), non-aged and aged biodiesel, diesel fuel with 5 % biodiesel, non-aged and aged B10 (heating oil with 10 % biodiesel) at 20 °C, 40 °C and 70 °C. Mass, tensile strength and breaking elongation of the test specimens were determined before and after the exposure for 84 days in the fuels. The visual examination of some elastomer test specimens clearly showed the great volume increase until break or partial dissolution. Shore hardness A and D (for PA) were determined before and after exposure of the test specimens in the biofuels for 42 days.
There is not determined a threshold for the reduction in tensile properties and Shore hardness in the international standards. Therefore, a threshold of 15 % was set for the evaluation of the compatibility. The sealing materials CR, CSM, EPDM, IIR and NBR were generally not resistant to biodiesel and B10. In summary, it can be therefore stated that the chemical resistance of the fluoropolymers FKM and FVMQ in fuels and biofuels is the best one.
Biodiesel is subject to degradation processes like oil and grease. The oxidative degradation products of vegetable oil esters in biodiesel particularly lead to enhanced sedimentation in blended fuels.
The polarity of biodiesel increases its solvency and facilitates permeation and extraction. Solvation, swelling and/or extraction lead to changes in the physical properties and chemical changes of polymeric materials. It also accelerates the degradation (hydrolysis and oxidation) of these materials with the loss of additives and stabilizers.
The objective of this research was to determine the resistance of frequently used polymeric materials such as ACM, EPDM, FKM, FVMQ, CR, CSM, IIR, HNBR, NBR, PA, PE; POM, PUR, PVC and VMQ in biodiesel and heating oil with 10 %/20 % biodiesel (B10/B20) at 40°C and 70°C.
Mass, tensile strength and breaking elongation of the test specimens were determined before and after the exposure for 84 days in the biodiesel heating oil blends. The visual examination of some elastomer test specimens clearly showed the great volume increase until break or partial dissolution. Shore hardness A and D were determined before and after exposure of the test specimens in the biofuels for 42 days.
The elastomers CR, CSM, EPDM, IIR, NBR and VMQ were generally not resistant to biodiesel and B10 at 40°C and 70°C. FKM, ACM, HNBR, PA, PE, POM, and PVC showed high compatibility in B10/B20 at 40°C. A lower compatibility was determined for ACM in biodiesel. ACM and HNBR were not resistant in B20 at 70°C.
Biodiesel is viewed as a major source of energy. In areas such as the European Union, where 80 % of the oil-based fuel is imported, there is also the desire to reduce dependence on external oil supplies.
Materials compatibility is a major concern whenever the fuel composition is changed. The question arises of whether polymeric materials are resistant to heating oil with 20 % biodiesel (B20) in comparison to pure heating oil.
The polarity of biodiesel increases its solvency and facilitates permeation and extraction. Solvation, swelling and/or extraction lead to changes in the physical properties. Extraction alters the fuel chemistry. These chemical changes could also accelerate the degradation (hydrolysis and oxidation) of the polymeric material with the loss of additives and stabilizers.
The objective of this research was to determine the resistance of frequently used materials for components in middle distillate facilities such as ACM, FKM, HNBR, PA, PE, POM, PUR and PVC in heating oil and heating oil blend B20 for 84 days at 40 °C, and FKM, HNBR, PA, POM, PUR and PVC at 70 °C.
Mass, tensile strength, breaking elongation and Shore hardness A (D) of the test specimens were determined before and after exposure for 84 (42) days in the test fuels under static conditions.
For the investigations under compressed conditions, the mass and the compression set of FKM test specimens were determined before and after exposure for 3, 7, 14, 28, 56 and 90 days in B20 at 40 °C and 70 °C according to ISO 815-1 “Rubber, vul-canized or thermoplastic - determination of compression set – Part 1: At ambient or elevated temperatures”.
There is not determined a threshold for the reduction in tensile properties and Shore hardness in the international standards. Therefore, a threshold of 15 % was determined for the evaluation of the compatibility.
The change of tensile strength and breaking elongation of test specimens made of ACM, FKM, HNBR, PA, PE, POM, PUR and PVC exposed to heating oil and the blend B20 was less than 15 % at 40 °C. A maximum reduction in Shore hardness A of 14 % was determined for ACM at 40 °C and for HNBR of 15 % at 70 °C.
It can be concluded that ACM, FKM, HNBR, PA, PE, POM, PVC and PUR were resistant in B20 at 40°C. FKM, PA, POM and PVC were evaluated as resistant in heat-ing oil and B20 at 70 °C, HNBR and PUR were not resistant in these fuels at 70°C.
Based on the mass increase and compression set values of FKM test specimens it can be stated that FKM is resistant in B20 under compressed conditions at 40 °C and 70 °C.
Die Bewertung der Werkstoffbeständigkeit ist von großer Bedeutung bei Änderung der Zusammensetzung der Kraftstoffe und des Heizöls, insbesondere die Frage nach der Beständigkeit der Dichtungswerkstoffe bei Zusätzen von Bioethanol und Biodiesel (Rapsölfettsäuremethylester).
Vorhergehende Untersuchungen (Messungen der Veränderungen der Masse, der Zugeigenschaften und der Härte) bezogen sich auf die Bewertung der Beständigkeit häufig verwendeter Dichtungswerkstoffe wie FKM, FVMQ, VMQ, EPDM, CR, CSM, IIR, PA, NBR und PUR in Kraftstoffen und Heizöl mit 10 % Biodiesel (nicht gealtert und bis zu 5 Jahre gealtert) unter statischen Bedingungen.
Ziel der Untersuchungen war die Bewertung der Beständigkeit von Fluorkautschuk unter verpressten Bedingungen in Analogie zu den Einsatzbedingungen in der Praxis. Die Masse und der Druckverformungsrest von Prüfkörpern aus FKM wurden vor und nach der Auslagerung über einen Zeitraum von 3, 7, 14, 28, 56 und 90 Tagen in E10 (Kraftstoff mit max. 10 % Ethanol), E85 (Kraftstoff mit 85 % Ethanol), Biodiesel (Rapsölfettsäuremethylester), Super (Kraftstoff mit max. 5 % Ethanol), Dieselkraftstoff mit max. 5 % Biodiesel, Super Plus (Kraftstoff ohne Ethanolzusatz) und Heizöl mit 10 % Biodiesel (B10) bei 40 °C gemäß ISO 815-1 bestimmt. Die Druckverformungsrestprüfung zählt neben der Messung der Härte, der Dichte und der Zugeigenschaften zu den wichtigsten Grundprüfverfahren der Elastomerindustrie. Nach Ende der Auslagerung in den Kraftstoffen und der Aufhebung der Verpressung wur-de der Druckverformungsrest der Prüfkörper in regelmäßigen Zeitabständen bis zu einer Rücktrocknung > 90 Tage bestimmt. Zum Vergleich wurden Prüfkörper aus FKM ohne Kraftstoff oder Heizöl unter Verpressung bei 40 °C ausgelagert.
Die Masseänderung der Prüfkörper aus FKM betrug nach 90 Tagen Auslagerung in E10 9 %, in Super 8 %, in E85 4% und 0,6 % in Biodiesel. Die Erhöhung der Masse und die damit verbundene Quellung der Prüfkörper in E10 und Super mit 5 – 10% Ethanolzusatz hatte einen Einfluss auf den Druckverformungsrest, der sprunghaften Veränderungen unterlag im Vergleich zu den Werten nach Auslagerung in Biodiesel, Dieselkraftstoff und Heizöl B10 bei 40 °C. Zum Vergleich, unter statischen Bedingungen verringerte sich die Zugfestigkeit der Prüfkörper aus FKM nach Auslagerung in E10 bei 40 °C um 31 % und die Reißdehnung um 18 %.
In der Bundesrepublik Deutschland werden über 400 Mio.t Gefahrgüter jährlich in Tankfahrzeugen, Aufsetztanks, Batteriefahrzeugen, Eisenbahnkesselwagen und Tankcontainern befördert, davon etwa 150 Millionen Tonnen im Straßengüterverkehr. Zu den Hauptschadensursachen zählt die Korrosion, wobei die gleichmäßige und ungleichmäßige Flächenkorrosion die Korrosionsart ist, die beim Chemikalientransport in Tanks am häufigsten auftritt. Viele Schäden durch Lochkorrosion entstehen beim Transport von chloridhaltigen Medien bei Anwesenheit von Feuchtigkeit.
Die BAM-Liste - Anforderungen an Tanks für die Beförderung gefährlicher Güter - ist Grundlage für die stoffbezogenen Baumusterzulassungen für Tankcontainer und ortsbewegliche Tanks zur Beförderung gefährlicher Güter durch die BAM seit der Herausgabe der 1. Auflage 1989. In die BAM-Liste wurden vorrangig solche gefährlichen Güter aufgenommen, die potenziell in Tanks befördert werden können. Die Beständigkeitsbewertungen gebräuchlicher metallischer Tankwerkstoffe und polymerer Dichtungs-, Beschichtungs- und Auskleidungswerkstoffe werden auch bei der Zulassung von Kesselwagen und Tankfahrzeugen als Erkenntnisquelle verwendet. Diese Daten sind aber unter sorgfältiger Überprüfung der Übertragbarkeit auch für andere praktische Anwendungen und unter Berücksichtigung der jeweiligen Praxisbedingungen auch als Ratgeber für Verpackungen, IBC, Lagerbehälter, Rohrleitungen usw. aus metallischen Werkstoffen anwendbar.
In den internationalen Gefahrgutverordnungen ADR, RID und IMDG-Code wird nach einer vorgegebenen Prüffrist eine innere Besichtigung der Tanks gefordert. Bei Tankcontainern beträgt diese Prüffrist im ADR/RID, Kap. 6.8 , fünf Jahre (bei der Beförderung von ortsbeweglichen Tanks nach ADR/RID, Kap. 6.7, und nach dem IMDG-Code 2½ Jahre) und bei Tankfahrzeugen sechs Jahre. Im RID wird für Eisenbahnkesselwagen eine Prüffrist von acht Jahren für die Innenbesichtigung vorgeschrieben. Für die Dauer der Prüfintervalle muss die Werkstoffbeständigkeit der Tankwerkstoffe gewährleistet sein.
Hydrogen gas diffusivity of fourteen glasses of the Na2O-Al2O3-SiO2 system are studied along the joins quartzalbite-jadeite-nepheline (Qz-Ab-Jd-Np, fully polymerized) and albite-sodium disilicate (Ab-Ds, depolymerized).
Density measurements show that ionic porosity decreases from 54.4% (Qz) to 51.5% (Np) and from 52.4% (Ab) to 50.2% (Ds). Hydrogen diffusivity D follows similar trends but at another scale. D at 523 K decreases from 4×10−12 to 3×10−14m2 s−1 (Qz-Np) and from 4×10−13 to 3×10−15m2 s−1 (Ab-Ds). Charge compensating Na+ acting as a filling agent in fully polymerized network structures leads to up to one order of Magnitude higher diffusivities as depolymerized glass structures of the same SiO2 content where Na+ takes the role of a
modifier ion. Temperature dependence of the diffusivity indicates that both the activation energy involved with the moving H2 molecule as well as the accessible volume in the structure contribute to this compositional trend.
3D coherence scanning interferometry (CSI) is anoptical, non-contact and rapide measurement technique using a defined bandwidth of white light at normal incidence. White light interference microscopy (WLIM) providest here-dimensional surface topometry data up to a resolution of 0.4 µm lateral and 0.1 nm vertical. Three operating modi, surface, films and advanced films, enable measurements of step heights, roughness, wear volume, cone angle, surface pattern and layer thickness. Traceability to SI system is ensured by certified standards (PTB/NIST) within a DAkkS DIN EN ISO/IEC 17025:2018 accredited lab.
Verstärkt auftretende Schäden in Betonfahrbahndecken des Bundesfernstraßennetzes, die mit einer Alkali-Kieselsäure-Reaktion (AKR) in Verbindung gebracht werden, haben zu einer massiven Verschärfung der Prüfvorschriften zur Bewertung der Alkaliempfindlichkeit von Ge-steinskörnungen geführt. Die damit verbundene Einschränkung potenziell für den Straßenbau einsetzbarer Gesteinskörnungen ruft eine verstärkte Ressourcenknappheit und ein erhöhtes Transport- und damit einhergehendes Kostenaufkommen hervor. Vor diesem Hintergrund wird nach neuartigen AKR-Vermeidungsstrategien gesucht, die auch eine Verwendung grenzwertig alkaliempfindlich eingestufter Gesteinskörnungen erlaubt. Einen möglichen Lösungsansatz stellt in diesem Kontext die Innenhydrophobierung des Fahrbahndeckenbetons dar. Es soll so durch die Behinderung des Feuchte- und Tausalzeintrags in den Beton der AKR-Schädigungs-prozess signifikant vermindert werden. Für die Bewertung der Leistungsfähigkeit der Innen-hydrophobierung zur Vermeidung einer schädigenden AKR in Betonfahrbahndecken wird zur-zeit im Auftrage der BASt an der BAM ein Forschungsvorhaben bearbeitet. Im Rahmen dieses Beitrags werden erste ausgewählte Ergebnisse dieses Forschungsvorhabens vorgestellt. So wird exemplarisch an einem Oberbeton (0/8) mit einer alkaliempfindlichen Gesteinskörnung der Einfluss eines Hydrophobierungsmittels auf die Frisch- und Festbetoneigenschaften ganz-heitlich aufgezeigt und bewertet. Bei Letzteren stehen zunächst die mechanischen und hygri-schen Parameter sowie der Frost-Tausalzwiderstand im Vordergrund. In einem weiteren Schritt wird der Einfluss der Innenhydrophobierung auf die schädigende AKR mittels verschie-denartiger AKR-Performanceprüfungen beleuchtet.
AKR an Betonfahrbahndecken – ausgewählte Einflussgrößen und neuartige AKR-Vermeidungsstrategie
(2019)
In den letzten Jahren sind im deutschen Bundesautobahnnetz vermehrt Schäden an vor 2005 hergestellten Betonfahrbahndecken aufgetreten, die mit einer Alkali-Kieselsäure-Reaktion (AKR) in Verbindung gebracht werden. Vor diesem Hintergrund werden in diesem Beitrag zunächst die Voraussetzungen und ausgewählte Einflussgrößen für eine schädigende AKR aufgezeigt. Besondere Aufmerksamkeit wird dabei der Rolle des Tausalzeintrags durch den Winterdienst bei Betonfahrbahndecken geschenkt. So wird mit Löseversuchen in 1 M KOH-Lösung zweier Gesteinskörnungen bei 80 °C gezeigt, dass mit zunehmender NaCl-Zugabe die Löslichkeit von SiO2 zunimmt und die von Al2O3 eine Verminderung erfährt. Basierend auf dem so exemplarisch erbrachten Nachweis für die Verstärkung der schädigenden AKR durch das Tausalz wird die Notwendigkeit und Richtigkeit der Durchführung von AKR-Betonversuchen mit Alkalizufuhr im ARS 04/2013 zur zukünftigen Vermeidung von AKR-Schäden an Betonfahrbahndecken im Rahmen von Neubau- und Erneuerungsmaßnahmen im Bundesfernstraßennetz belegt. Zusätzlich durchgeführte WS-Grundprüfungen nach dem ARS 04/2013 mit den beiden Gesteinskörnungen der Löseversuche veranschaulichen, dass die nach der Alkali-Richtlinie des DAfStb als unbedenklich eingestuften Gesteinskörnungen bei den Betonversuchen mit Alkalizufuhr durchaus als alkaliempfindlich bewertet werden können. Dies wiederum führt zu einer Verminderung der für den Betonstraßenbau verfügba-ren Gesteinskörnungen. Vor diesem Hintergrund wird nach neuartigen AKR-Vermeidungsstrategien gesucht, die auch eine Verwendung der als grenzwertig alkaliemp-findlich eingestuften Gesteinskörnungen erlaubt. Einen möglichen Lösungsansatz stellt in diesem Kontext die Innenhydrophobierung des Fahrbahndeckenbetons dar. Es soll so durch die Behinderung des Feuchte- und Tausalzeintrags in den Beton der AKR-Schädigungsprozess signifikant vermindert werden. Für die Bewertung der Leistungsfähigkeit der Innenhydrophobierung zur Vermeidung bzw. Verminderung einer schädigenden AKR in Betonfahrbahndecken wird zurzeit im Auftrage der BASt an der BAM ein Forschungsvorha-ben bearbeitet. Im Rahmen dieses Beitrags werden erste Ergebnisse dieses Projekts vorge-stellt. So wird exemplarisch an einem Oberbeton (D > 8)/Unterbeton und einem Oberbeton 0/8 mit einer alkaliempfindlichen Gesteinskörnung der Einfluss zweier Hydrophobierungsmit-tel auf die Frisch- und Festbetoneigenschaften ganzheitlich aufgezeigt und bewertet. Bei Letz-teren stehen zunächst die mechanischen und hygrischen Parameter sowie der Frost-Tausalzwiderstand im Vordergrund. In einem weiteren Schritt wird der Einfluss beider Hydro-phobierungsmittel auf die schädigende AKR mittels AKR-Betonversuchen mit Alkalizufuhr beleuchtet. Dabei gelangen ergänzend zur Beurteilung des Tausalzeintrags die Laser-Induced Breakdown Spectroscopy (LIBS) und zur Bewertung der Ausprägung der AKR und sekundä-ren Ettringitbildung (SEB) die Dünnschliffmikroskopie zum Einsatz.
AKR an Betonfahrbahndecken - ausgewählte Einflussgrößen und neuartige AKR-Vermeidungsstrategie
(2019)
In den letzten Jahren sind im deutschen Bundesautobahnnetz vermehrt Schäden an vor 2005 hergestellten Betonfahrbahndecken aufgetreten, die mit einer Alkali-Kieselsäure-Reaktion(AKR) in Verbindung gebracht werden. Vor diesem Hintergrund werden in diesem Beitrag zunächst die Voraussetzungen und ausgewählte Einflussgrößen für eine schädigende AKR aufgezeigt.
Besondere Aufmerksamkeit wird dabei der Rolle des Tausalzeintrags durch den Winterdienst bei Betonfahrbahndecken geschenkt. So wird mit Löseversuchen in 1 M KOH-Lösung zweier Gesteinskörnungen bei 80 °C gezeigt, dass mit zunehmender NaCI-Zugabe die Löslichkeit von SiÖ2 zunimmt und die von AI2O3 eine Verminderung erfährt. Basierend auf dem so exemplarisch erbrachten Nachweis für die Verstärkung der schädigenden AKR durch das Tausalz wird die Notwendigkeit und Richtigkeit der Durchführung von AKR-Betonversuchen mit Alkalizufuhr im ARS 04/2013 zur zukünftigen Vermeidung von AKR-Schäden an Betonfahrbahndecken im Rahmen von Neubau- und Erneuerungsmaßnahmen im Bundesfernstraßennetz belegt. Zusätzlich durchgeführte WS-Grundprüfungen nach dem ARS 04/2013 mit den beiden Gesteinskörnungen der Löse versuche veranschaulichen, dass die nach der Alkali-Richtlinie des DAfStb als unbedenklich eingestuften Gesteinskörnungen bei den Betonversuchen mit Alkalizufuhr durchaus als alkaliempfindlich bewertet werden können. Dies wiederum führt zu einer Verminderung der für den Betonstraßenbau verfügbaren Gesteinskörnungen.
Vor diesem Hintergrund wird nach neuartigen AKR-Vermeidungsstrategien gesucht, die auch eine Verwendung der als grenzwertig alkaliempfindlich eingestuften Gesteinskörnungen erlaubt.
Einen möglichen Lösungsansatz stellt in diesem Kontext die Innenhydrophobierung des Fahrbahndeckenbetons dar. Es soll so durch die Behinderung des Feuchte- und Tausalzeintrags in den Beton der AKR-Schädigungsprozess signifikant vermindert werden. Für die Bewertung der Leistungsfähigkeit der Innenhydrophobierung zur Vermeidung bzw. Verminderung einer schädigenden AKR in Betonfahrbahndecken wird zurzeit im Aufträge der BASt an der BAM ein Forschungsvorhaben bearbeitet. Im Rahmen dieses Beitrags werden erste Ergebnisse dieses Projekts vorgestellt. So wird exemplarisch an einem Oberbeton (D > 8)/Unterbeton und einem Oberbeton 0/8 mit einer alkaliempfindlichen Gesteinskörnung der Einfluss zweier Hydrophobierungsmittel auf die Frisch- und Festbetoneigenschaften ganzheitlich aufgezeigt und bewertet. Bei Letzteren stehen zunächst die mechanischen und hygrischen Parameter sowie der Frost-Tausalzwiderstand im Vordergrund. In einem weiteren Schritt wird der Einfluss beider Hydrophobierungsmittel auf die schädigende AKR mittels AKR-Betonversuchen mit Alkalizufuhr beleuchtet. Dabei gelangen ergänzend zur Beurteilung des Tausalzeintrags die Laser-Induced Breakdown Spectroscopy (LIBS) und zur Bewertung der Ausprägung der AKR und sekundären Ettringitbildung (SEB) die Dünnschliffmikroskopie zum Einsatz.
AKR an Betonfahrbahndecken - ausgewählte Einflussgrößen und neuartige AKR-Vermeidungsstrategie
(2019)
In den letzten Jahren sind im deutschen Bundesautobahnnetz vermehrt Schäden an vor 2005 hergestellten Betonfahrbahndecken aufgetreten, die mit einer Alkali-Kieselsäure-Reaktion (AKR) in Verbindung gebracht werden. Vor diesem Hintergrund werden in diesem Beitrag zunächst die Voraussetzungen und ausgewählte Einflussgrößen für eine schädigende AKR aufgezeigt.
Besondere Aufmerksamkeit wird dabei der Rolle des Tausalzeintrags durch den Winterdienst bei Betonfahrbahndecken geschenkt. So wird mit Löseversuchen in 1 M KOH-Lösung zweier Gesteinskörnungen bei 80 °C gezeigt, dass mit zunehmender NaCI-Zugabe die Löslichkeit von SiÖ2 zunimmt und die von AI2O3 eine Verminderung erfährt. Basierend auf dem so exemplarisch erbrachten Nachweis für die Verstärkung der schädigenden AKR durch das Tausalz wird die Notwendigkeit und Richtigkeit der Durchführung von AKR-Betonversuchen mit Alkalizufuhr im ARS 04/2013 zur zukünftigen Vermeidung von AKR-Schäden an Betonfahrbahndecken im Rahmen von Neubau- und Erneuerungsmaßnahmen im Bundesfernstraßennetz belegt. Zusätzlich durchgeführte WS-Grundprüfungen nach dem ARS 04/2013 mit den beiden Gesteinskörnungen der Löse versuche veranschaulichen, dass die nach der Alkali-
Richtlinie des DAfStb als unbedenklich eingestuften Gesteinskörnungen bei den Betonversuchen mit Alkalizufuhr durchaus als alkaliempfindlich bewertet werden können. Dies wiederum führt zu einer Verminderung der für den Betonstraßenbau verfügbaren Gesteinskörnungen.
Vor diesem Hintergrund wird nach neuartigen AKR-Vermeidungsstrategien gesucht, die auch eine Verwendung der als grenzwertig alkaliempfindlich eingestuften Gesteinskörnungen erlaubt.
Einen möglichen Lösungsansatz stellt in diesem Kontext die Innenhydrophobierung des Fahrbahndeckenbetons dar. Es soll so durch die Behinderung des Feuchte- und Tausalzeintrags in den Beton der AKR-Schädigungsprozess signifikant vermindert werden. Für die Bewertung der Leistungsfähigkeit der Innenhydrophobierung zur Vermeidung bzw. Verminderung einer schädigenden AKR in Betonfahrbahndecken wird zurzeit im Aufträge der BASt an der BAM ein Forschungsvorhaben bearbeitet. Im Rahmen dieses Beitrags werden erste Ergebnisse dieses Projekts vorgestellt. So wird exemplarisch an einem Oberbeton (D > 8)/Unterbeton und einem Oberbeton 0/8 mit einer alkaliempfindlichen Gesteinskörnung der Einfluss zweier Hydrophobierungsmittel auf die Frisch- und Festbetoneigenschaften ganzheitlich aufgezeigt und bewertet. Bei Letzteren stehen zunächst die mechanischen und hygrischen Parameter sowie der Frost-Tausalzwiderstand im Vordergrund. In einem weiteren Schritt wird der Einfluss beider Hydrophobierungsmittel auf die schädigende AKR mittels AKR-Betonversuchen mit Alkalizufuhr beleuchtet. Dabei gelangen ergänzend zur Beurteilung des Tausalzeintrags die Laser-Induced Breakdown Spectroscopy (LIBS) und zur Bewertung der Ausprägung der AKR und sekundären Ettringitbildung (SEB) die Dünnschliffmikroskopie zum Einsatz.
Verstärkt auftretende Schäden in Betonfahrbahndecken des Bundesfernstraßennetzes, die mit einer Alkali-Kieselsäure-Reaktion (AKR) in Verbindung gebracht werden, haben zu einer massiven Verschärfung der Prüfvorschriften zur Bewertung der Alkaliempfindlichkeit von Ge-steinskörnungen geführt. Die damit verbundene Einschränkung potenziell für den Straßenbau einsetzbarer Gesteinskörnungen ruft eine verstärkte Ressourcenknappheit und ein erhöhtes Transport- und damit einhergehendes Kostenaufkommen hervor. Vor diesem Hintergrund wird nach neuartigen AKR-Vermeidungsstrategien gesucht, die auch eine Verwendung grenzwertig alkaliempfindlich eingestufter Gesteinskörnungen erlaubt. Einen möglichen Lösungsansatz stellt in diesem Kontext die Innenhydrophobierung des Fahrbahndeckenbetons dar. Es soll so durch die Behinderung des Feuchte- und Tausalzeintrags in den Beton der AKR-Schädigungs-prozess signifikant vermindert werden. Für die Bewertung der Leistungsfähigkeit der Innen-hydrophobierung zur Vermeidung einer schädigenden AKR in Betonfahrbahndecken wird zur-zeit im Auftrage der BASt an der BAM ein Forschungsvorhaben bearbeitet. Im Rahmen dieses Beitrags werden erste ausgewählte Ergebnisse dieses Forschungsvorhabens vorgestellt. So wird exemplarisch an einem Oberbeton (0/8) mit einer alkaliempfindlichen Gesteinskörnung der Einfluss eines Hydrophobierungsmittels auf die Frisch- und Festbetoneigenschaften ganzheitlich aufgezeigt und bewertet. Bei Letzteren stehen zunächst die mechanischen und hygrischen Parameter sowie der Frost-Tausalzwiderstand im Vordergrund. In einem weiteren Schritt wird der Einfluss der Innenhydrophobierung auf die schädigende AKR mittels verschiedenartiger AKR-Performanceprüfungen beleuchtet.
In Vivo Biotransformations of Indium Phosphide Quantum Dots Revealed by X‑Ray Microspectroscopy
(2019)
Many attempts have been made to synthesize cadmium-free quantum dots
(QDs), using nontoxic materials, while preserving their unique optical properties. Despite impressive advances, gaps in knowledge of their intracellular fate, persistence, and excretion from the targeted cell or organism still exist, precluding clinical applications. In this study, we used a simple model organism (Hydra vulgaris) presenting a tissue grade of organization to determine the biodistribution of indium phosphide (InP)-based QDs by X-ray fluorescence imaging. By complementing elemental imaging with In L-edge X-ray absorption near edge structure, unique information on in situ chemical speciation was obtained. Unexpectedly, spectral profiles indicated the appearance of In−O species within the first hour post-treatment, suggesting a fast degradation of the InP QD core in vivo, induced mainly by carboxylate groups. Moreover, no significant difference in the behavior of bare core QDs and QDs capped with an inorganic Zn(Se,S) gradient shell was observed. The results paralleled those achieved by treating animals with an equivalent dose of indium salts, confirming the preferred bonding type of In3+ ions in Hydra tissues. In conclusion, by focusing on the chemical identity of indium along a 48 h long journey of QDs in Hydra, we describe a fast degradation process, in the absence of evident toxicity. These data pave the way to new paradigms to be considered in the biocompatibility assessment of QD-based biomedical applications, with greater emphasis on the dynamics of in vivo biotransformations, and suggest strategies to drive the design of future applied materials for nanotechnology-based diagnosis and therapeutics.
With the goal to improve their photostability, InP-based QDs are passivated with three types of inorganic shells, namely (i) a gradient ZnSexS1−x shell, (ii) an additional ZnS shell on top of the gradient shell with two different thicknesses (core/shell/shell, CSS), (iii) an alumina coating on top of ZnS. All three systems have photoluminescence Quantum yields (PLQY) > 50%and similar PL decay times (64–67 ns). To assess their photostability they are incorporated into a transparent poly (methyl methacrylate) (PMMA) matrix and exposed to continuous irradiation with simulated sunlight in a climate chamber. The alumina coated core/shell system exhibits the highest stability in terms of PLQY Retention as well as the lowest shift of the PL maximum and lowest increase of the PL linewidth, followed by the CSS QDs and finally the gradient shell system. By means of XPS studies we identify the degradation of the ZnS outer layer and concomitant xidation of the emissive InZnP core as the main origins of degradation in the gradient structure. These modifications do not occur in the case of the alumina-capped sample, which exhibits excellent chemical stability. The gradient shell and CSS systems could be transferred to the aqueous phase using surface ligand exchange with penicillamine. Cytotoxicity studies on human primary keratinocytes revealed that exposure for 24 h to 6.25–100 nM of QDs did not affect cell viability. However, a trend toward reduced cell proliferation is observed for higher concentrations of gradient shell and CSS QDs with a thin ZnS shell, while CSS QDs with a thicker ZnS shell do not exhibit any impact.
Semiconductor nanocrystals (quantum dots, QDs) are well known for their superior photophysical properties and enabled advancements in several key technologies of the 21st century and numerous technological applications. However, the most studied II-VI semiconductor nanocrystals contain the toxic heavy metal element cadmium, which is limiting their utilization in commercial applications. This has drawn the interest to alternative materials with less toxicity but having similar photophysical features.
The newest generation of TV screens based on QDs have shown that there is a promising environmentally friendly alternative with similar optoelectronic properties, namely indium phosphide (InP) QDs. InP QDs possess a bulk band gap of 1.35 eV with an exciton Bohr radius of ca. 10 nm and thus allow to tune their photoluminescence (PL) from the visible to the near-infrared. Tuning the size and shape of InP QDs and thus tailor their optoelectronic properties can be achieved by different strategies, which range from different types and concentrations of precursors, synthesis temperature or post-synthetic manipulations like etching. The incorporation of other elements like Gallium within the InP core synthesis is another possibility. Using a GaP intermediate layer before growing a ZnS shell has been shown to increase the PL quantum yield, which has been attributed to reduced lattice strain and the removal of phosphor vacancies. Different Ga precursors were investigated but a thorough investigation in terms of their reactivity, localization in the QD and influence on the photophysical properties is lacking to date.
In this contribution we will present the detailed investigation of the presence of two different Ga precursors within the InP core synthesis. Photophysical characterizations (steady-state and PL life-time measurements), transmission electron microscopy, XRD and EDX gave insights into the reactivity of the Ga precursors, the Ga localization in the InP core and influences on the photophysical properties. The variation of the precursor and surfactant concentration and the utilization of different ligands for the Ga precursor allowed tuning the PL emission towards the blue or the red. Depending on the used precursor type we observed the formation of larger-sized InP/GaP core/shell nanocrystals or the formation of InGaP alloy structures enabling to assess the blue range of emission (475 nm).
The precise analysis of cation diffusion profiles through corrosion scales is an important aspect to evaluate corrosion phenomena under multicomponent chemical load, as during high‐temperature corrosion under deposits and salts. The present study shows a comprehensive analysis of cation diffusion profiles by electron microprobe analysis and microbeam X‐ray absorption near edge structure (µ‐XANES) spectroscopy in mixed oxide/sulfide scales grown on Fe–Cr model alloys after exposing them to 0.5% SO2. The results presented here correspond to depth‐dependent phase identification of oxides and sulfides in the corrosion scales by µ‐XANES and the description of oxidation‐state‐dependent diffusion profiles. Scales grown on low‐ and high‐alloyed materials show both a well‐pronounced diffusion profile with a high concentration of Fe3+ at the gas and a high concentration of Fe2+ at the alloy interface. The distribution of the cations within a close‐packed oxide lattice is strongly influencing the lattice diffusion phenomena due to their different oxidation states and therefore different crystal‐field preference energies. This issue is discussed based on the results obtained by µ‐XANES analysis.
Recent facade fires worldwide have driven change in regulations for façade fire safety in different parts of the world. The Grenfell Tower fire 2017 in London triggered a thorough investigation of many aspects of the fire. One investigation was about the UK building regulations from Dame Judith Hackett. This investigation compares the UK with the situation other parts of the world. Key findings of the review of building regulations by Judith Hackett are:
Glass strength and fatigue is limited by surface cracks. As subcritical crack growth (SCCG) is governed by ambient humidity, stress corrosion at the crack tip is widely accepted to be the underlying mechanism. However, as water is known to have decisive effect on glass properties and can rapidly enter the crack tip near glass region, SCCG could be affected by such water related phenomena. We tried to mimic these effects studying water dissolution and speciation, mechanical properties, and SCCG in water-bearing glasses. For this purpose, glasses up to 8 wt% water have been prepared by means of high-pressure melting of glass powder - water mixtures.
As part of this effort, SCCG in dry and hydrous commercial micros¬cope slide glass (CW = 6 wt%) was studied in double cantilever beam (DCB) geometry and sub-Tg relaxation was measured by Dynamic Mechanical Analysis (DMA).
For SCCG in ambient air (24% r.h.), SCCG was promoted by the presence of 6wt% bulk water with respect to the dry glass. On the other hand, stress intensity values, KI, required to cause slow crack growth (v < 10-6 ms-1) resemble literature findings for float glass of similar composition in liquid water, which might represent the maximum possible promoting effect of ambient water on SCCG.
For SCCG in vacuum (10-3 mbar), dissolved bulk water causes even more pronounced effects. Most strikingly, it strongly decreases the slope of the log v(KI)-curve, which is a measure of dissipated energy during fracture. A strong increase of sub-Tg relaxation with increasing water content was confirmed by DMA. As a consequence, slow crack growth occurs at KI values as measured in the dry glass whereas fast crack growth occurs at much larger KI than that of the dry glass. Kinks and shoulders shown by the inert log v(KI)-curve indicate that bulk water does not simply affect bulk mechanical properties.
Environmental conditions are known to influence sub-critical crack growth (SCCG) that starts from microscopic flaws at the glass surface, leading to stress corrosion phenomena at the crack tip. The processes at the crack tip are complex and water has been identified as a key component governing SCCG at low crack velocities (region I). In particular, the influence of humidity accelerating crack propagation is well studied for dry industrial soda-lime silicate glasses (< 1000 ppm water). To shed light on this influence, the effect of water is mimicked by studying SCCG in water-bearing glasses. For this purpose, water-bearing silicate glasses of up to 8 wt% total water were synthesized in an internally heated pressure vessel at 0.5 GPa and compared to dry glasses. SCCG was measured using the double cantilever beam technique. For dry glasses, three trends in the crack growth velocity versus stress intensity, KI, curve were found. The slope in region I, limited by environmental corrosion, increases in the order soda-lime silicate < sodium borosilicate < barium calcium silicate < sodium zinc silicate < sodium aluminosilicate glass. The velocity range of region II, reflecting the transition between corrosion affected and inert crack growth (region III), varies within one order of magnitude among these glasses. The KI region of inert crack growth strongly scatters between 0.4 and 0.9 MPam1/2. For hydrous glasses, it is found that water strongly decreases Tg, form a new sub-Tg relaxation peak caused by molecular water, and makes the glasses more prone to SCCG. The observed trends will be discussed in terms of the effects of Youngs Modulus on strain energy release rate and energy dissipation related to glass relaxation phenomena.
Ambient water influences sub-critical crack growth (SCCG) from microscopic surface flaws, leading to stress corrosion at the crack tip. The complex influence of humidity accelerating slow crack propagation (region I) is well studied only for dry commercial NCS glass (< 1000 ppm water). To shed light on this influence, the effect of water is mimicked by studying SCCG water-bearing glasses. For this purpose, water-bearing silicate glasses of 8 wt% total water were synthesized at 0.5 GPa and compared to dry glasses. SCCG was measured in double cantilever beam geometry. For dry glasses, 3 trends in crack velocity vs. stress intensity, KI, curve were found. The slope in region I increases in the order NCS < NBS < BaCS < NZnS < NAS glass. The velocity range of region II, reflecting the transition between corrosion affected and inert crack growth (region III), varies within one order of magnitude among these glasses. The KI region of inert crack growth strongly scatters between 0.4 and 0.9 MPam0.5. For hydrous glasses, it is found that water strongly decreases Tg, form a new sub-Tg internal friction peak caused by molecular water, and makes the glasses more prone to SCCG. The observed trends will be discussed in terms of the effects of Youngs Modulus on the strain energy release rate and energy dissipation related to mechanical glass relaxation phenomena.
Die Untersuchung von Schallausbreitung in periodischen Strukturen ist aktuell von großem Interesse für eine zielgerichtete Beeinflussung von Schallwellen in einem großen Frequenzbereich. Hierbei liegt der Fokus insbesondere auf den phononische Kristalle (PnK’s), einer periodischen Anordnung von Streuzentren in einer Matrix. PnK’s können neben anderen Anwendungen, wie der Sensoranwendung oder der Nutzung als effektiver Wellenleiter, als Schallisolator dienen. In dieser Arbeit wird ein neuartiger PnK aus einer periodischen Anordnung von Zylindern untersucht, welcher zur Schallisolation verwendet werden kann. Zunächst wird die Struktur simuliert, dabei wird ein achsensymmetrisches Modell mit einem 3D-Modell verglichen. Im Anschluss wird die simulierte Geometrie gefertigt und vermessen.
Die Messung von Flüssigkeitskonzentrationen in Rohrsystemen ist von großem Interesse für viele unterschiedliche Anwendungen. Die meisten Messsysteme sind jedoch nicht in der Lage, die Flüssigkeit direkt im Rohr zu untersuchen und es muss eine zusätzliche Vorrichtung, wie z.B. einem Bypass, angebracht werden, welche den Kontakt zwischen Flüssigkeit und Sensor ermöglicht.
Um den Einbauaufwand gering zu halten und die Strömungseigenschaften des Rohres nicht zu beeinflussen, wird ein neuartiges Messsystem entwickelt, welches als Teil der Rohrwand ausgeführt werden kann. Dieses neuartige System ist angelehnt an die Idee der phononischen Kristallen (PnK). PnK’s bestehen im Allgemeinen aus einem Matrixmaterial, in welchem Streuzentren periodisch angeordnet sind. Dies führt beim Eintreffen einer akustischen Welle in definierten Frequenz-bereichen, sogenannter Bandlücken, zu zunehmender destruktiven Interferenz. Wird innerhalb einer solchen Bandlücke durch Einbringen einer flüssigkeitsgefüllten Kavität ein Resonanzverhalten erzeugt, kann dies genutzt werden, um die Flüssigkeit zu analysieren.
Im Rahmen von Voruntersuchung wird zunächst das akustische Verhalten des PnK’s, welcher für die Sensorentwicklung genutzt werden soll, unter Vernachlässigung der Flüssigkeit ausführlich untersucht. Hierbei werden zunächst die Bandlücken ermittelt und das Übertragungsverhalten betrachtet. Dieses wird im Anschluss experimentell überprüft.
Die Messung von Flüssigkeitskonzentrationen in Rohrsystemen ist von großem Interesse für viele unterschiedliche Anwendungen. Die meisten Messsysteme sind jedoch nicht in der Lage, die Flüssigkeit direkt im Rohr zu untersuchen und es muss eine zusätzliche Vorrichtung, wie z.B. einem Bypass, angebracht werden, welche den Kontakt zwischen Flüssigkeit und Sensor ermöglicht.
Um den Einbauaufwand gering zu halten und die Strömungseigenschaften des Rohres nicht zu beeinflussen, wird ein neuartiges Messsystem entwickelt, welches als Teil der Rohrwand ausgeführt werden kann. Dieses neuartige System ist angelehnt an die Idee der phononischen Kristallen (PnK). PnK’s bestehen im Allgemeinen aus einem Matrixmaterial, in welchem Streuzentren periodisch angeordnet sind. Dies führt beim Eintreffen einer akustischen Welle in definierten Frequenz-bereichen, sogenannter Bandlücken, zu zunehmender destruktiven Interferenz. Wird innerhalb einer solchen Bandlücke durch Einbringen einer flüssigkeitsgefüllten Kavität ein Resonanzverhalten erzeugt, kann dies genutzt werden, um die Flüssigkeit zu analysieren.
Im Rahmen von Voruntersuchung wird zunächst das akustische Verhalten des PnK’s, welcher für die Sensorentwicklung genutzt werden soll, unter Vernachlässigung der Flüssigkeit ausführlich untersucht. Hierbei werden zunächst die Bandlücken ermittelt und das Übertragungsverhalten betrachtet. Dieses wird im Anschluss experimentell überprüft. Hierzu werden neben herkömmlichen Fertigungsverfahren auch additive Verfahren zur Herstellung der Proben genutzt.
To date, there are very few technologies available for the conversion of low-temperature waste heat into electricity. Thermomagnetic generators are one approach proposed more than a century ago. Such devices are based on a cyclic change of magnetization with temperature. For thermomagnetic materials, we used a commercial magnetocaloric alloy with a transition temperature of 300 K.
To date, there are only very few technologies available for the conversion of low temperature waste heat to electricity. In this talk, we first describe the principle of thermomagnetic generators. Then we focus on the impact of topology of the magnetic circuit within thermomagnetic generators. We demonstrate that the key operational parameters strongly depend on the genus, i.e. the number of holes within the magnetic circuit.
In diesem Vortrag wird am Beispiel magnetischer Werkstoffe zur Energiewandlung gezeigt, wie röntgentomographische Untersuchungen zur Strukturaufklärung in Kompositen und Massivproben beitragen können. Die Bauteile werden zerstörungsfrei geprüft, um Risse, Poren und andere Defekte und ihren Einfluss auf die funktionellen Eigenschaften dreidimensional und rechtzeitig im Lebenszyklus des Werkstoffs zu charakterisieren. Kombiniert man Mikrotomographie mit anderen Methoden der magnetischen Werkstoffcharakterisierung, lassen sich einzigartige Aussagen über den Aufbau und die funktionellen Eigenschaften treffen.
To date, there are only very few technologies available for the conversion of low temperature waste heat to electricity. In this talk, we first describe the principle of thermomagnetic generators. Then we focus on the impact of topology of the magnetic circuit within thermomagnetic generators. We demonstrate that the key operational parameters strongly depend on the genus, i.e. the number of holes within the magnetic circuit.
Functional materials for energy conversion are important technology drivers needed for the implementation of low carbon energy. Therefore, researchers commonly focus on improving the intrinsic properties of a functional material. However, for applications, the extrinsic properties are at least as important as the intrinsic ones. Consequently, it is important to investigate and understand the external and internal structure of semi-finished products and especially defect dependent properties. The extrinsic properties may change during application and the life cycle of the material as well as through processing and molding steps.
Our studies show how X-ray tomographic (XCT) investigations can contribute to structure investigations in composites and massive samples using the example of magnetic materials for energy conversion. The components are tested non-destructively in 3D in order to localize and characterize cracks, pores, inclusions as well as other defects and their influence on the functional properties and also “in-time” during the life cycle of the material. Exsitu and in-situ experiments performed with non-destructive XCT are predestinated to follow damaging mechanisms of materials under certain load conditions, atmospheres or liquids, e.g. went through several working cycles of a functional material. By combining microtomography with other methods of magnetic and classical material characterization, unique statements about the structure and the functional properties can be made.
From the applications point of view, sometimes complex, three-dimensional geometries are needed to fully exploit the functional properties of the materials, e.g. to ensure a high surface area for heat exchange. Since many functional materials are brittle and difficult to form, shaping is often a big challenge. In principle, additive manufacturing processes offer the possibility to produce complex, porous components from poorly formable alloys.
If all stages of additive manufacturing are accompanied by X-ray tomographic imaging, the process of finding the optimal parameters for material processing can be significantly accelerated.
Based on the quality control of the initial powder material used and also investigations of the shape and arrangement of defects within the molten structure and their relationship with the melting path scanning strategy, Xray tomography has proven to be an ideal tool for additive manufacturing, even for functional materials. Overall, tomographic methods are important tools for the development of functional materials to application maturity.
Using magnetic materials for energy conversion as an example, this lecture shows how X-ray tomography investigations can contribute to structure elucidation in composites and solid samples. The components are tested non-destructively in order to characterize cracks, pores and other defects and their influence on the functional properties three-dimensionally and in good time in the life cycle of the material. If you combine microtomography with other methods of magnetic material characterization, you can make unique statements about the structure and the functional properties.
Using magnetic materials for energy conversion as an example, this lecture shows how X-ray tomography investigations can contribute to structure elucidation in composites and solid samples. The components are tested non-destructively in order to characterize cracks, pores and other defects and their influence on the functional properties three-dimensionally and in good time in the life cycle of the material. If you combine microtomography with other methods of magnetic material characterization, you can make unique statements about the structure and the functional properties.
To date, there are only very few technologies available for the conversion of low temperature waste heat to electricity. In this talk, we first describe the principle of thermomagnetic generators. Then we focus on the impact of topology of the magnetic circuit within thermomagnetic generators. We demonstrate that the key operational parameters strongly depend on the genus, i.e. the number of holes within the magnetic circuit.
To date, there are only very few technologies available for the conversion of low temperature waste heat to electricity. In this talk, we first describe the principle of thermomagnetic generators. Then we focus on the impact of topology of the magnetic circuit within thermomagnetic generators. We demonstrate that the key operational parameters strongly depend on the genus, i.e. the number of holes within the magnetic circuit.
To date, there are very few technologies available for the conversion of low-temperature waste heat into electricity. Thermomagnetic generators are one approach proposed more than a century ago. Such devices are based on a cyclic change of magnetization with temperature. For thermomagnetic materials, we used a commercial magnetocaloric alloy with a transition temperature of 300 K.
In diesem Vortrag wird am Beispiel magnetischer Werkstoffe zur Energiewandlung gezeigt, wie röntgentomographische Untersuchungen zur Strukturaufklärung in Kompositen und Massivproben beitragen können. Die Bauteile werden zerstörungsfrei geprüft, um Risse, Poren und andere Defekte und ihren Einfluss auf die funktionellen Eigenschaften dreidimensional und rechtzeitig im Lebenszyklus des Werkstoffs zu charakterisieren. Kombiniert man Mikrotomographie mit anderen Methoden der magnetischen Werkstoffcharakterisierung, lassen sich einzigartige Aussagen über den Aufbau und die funktionellen Eigenschaften treffen.
In diesem Vortrag wird am Beispiel magnetischer Werkstoffe zur Energiewandlung gezeigt, wie röntgentomographische Untersuchungen zur Strukturaufklärung in Kompositen und Massivproben beitragen können. Die Bauteile werden zerstörungsfrei geprüft, um Risse, Poren und andere Defekte und ihren Einfluss auf die funktionellen Eigenschaften dreidimensional und rechtzeitig im Lebenszyklus des Werkstoffs zu charakterisieren. Kombiniert man Mikrotomographie mit anderen Methoden der magnetischen Werkstoffcharakterisierung, lassen sich einzigartige Aussagen über den Aufbau und die funktionellen Eigenschaften treffen.
Boehmite nanoparticles has been successfully functionalized with APTES. After APTES functionalization further modification with tailored molecules e.g. via carboxylic acids is possible. The tailored surface functionalization is strongly enhanced by improved coupling protocols. Arbitrary variation of the functionalization degree is possible. Thereby the temperature stable APTES functionalization enables a wide range of functional groups.
By TGA-MS analysis strong evidence for the bonding situation of the APTES on the boehmite surface has been found. Additionally first experiments has been performed to predict the polymer-particle compatibility enhancement via reverse wetting angle measurements with AFM.
New Focus On Boehmite-Reinforced Nanocomposites Molecular Approach With Advanced FTIR-Techniques
(2019)
By FTIR-study it was possible to proof a chemical reaction between boehmite and the hardener of anhydride cured epoxy resins. Future studies can assume that the chemical environment of the resin system is changed in the surrounding of boehmite nanoparticles. This highly affects especially localized properties.
Water as side effect of reinforcing boehmite filler Local changes in anhydride cured epoxy resin
(2019)
Nanocomposites offer wide opportunities for lightweight constructions and enable reduction of weight and volume. Beside macroscopic toughening nanoparticle reinforced polymers show a soft interface around boehmite (AlOOH) filler nanoparticles. A related strong interaction between boehmite and the anhydride cured resin system is widely suspected in literature but not determined by structural Analysis. Determination of the molecular structure is important to allow simulations approaching the real system and predict future reinforcing effects.
DRIFT (diffuse refletance infrared fourier transformed) spectra of the boehmite reinforced anhydride cured epoxy show significant changes in the molecular structure compared to the neat polymer. Further investigations of the interactions between the single components of the resin system and the boehmite filler pointed out reactions between released water released from the boehmite filler and the anhydride hardener or amine accelerator. This leads to the discussion of competing polymerisation mechanisms that highly influence the polymer properties. Ongoing experiments and literature research approve that this impact of water is able to locally change the stoichiometrie, alter the curing mechanism or support an inhomogeneous crosslink density.
The freeze casting technique assisted with cryo thiol-ene photopolymerization is successfully employed for the fabrication of macroporous polymer-derived silicon oxycarbide with highly aligned porosity. It is demonstrated that the free radical initiated thiol-ene click reaction effectively cross-linked the vinyl-containing liquid polysiloxanes into infusible thermosets even at low temperatures. Furthermore, mixed solution- and suspension-based freeze casting is employed by adding silica nanopowders. SiOC/SiO2 foams with almost perfect cylindrical shapes are obtained, demonstrating that the presence of nano-SiO2 does not restrict the complete photoinduced cross-linking. The post-pyrolysis HF acid treatments of produced SiOC monoliths yields hierarchical porosities, with SiOC/SiO2 nanocomposites after etching demonstrating the highest specific surface area of 494 m2/g and pore sizes across the macro-, meso- and micropores ranges. The newly developed approach gives a versatile solution for the fabrication of bulk polymer-derived ceramics with controlled porosity.
Reliable performance of structural sealant glazing (SSG) systems is necessary to utilise advantages of SSG in glass facades. Conventional durability assessment of structural sealant joints is based on separated weathering tests and empirical fatigue testing. This work presents a new test methodology for performance assessment of SSGjoints at simultaneous weathering and two-dimensional mechanical loading. The climatic and mechanical load function were derived from common loading scenarios according to a worst case approach. A System test specimen, resembling a common SSG-joint, was exposed to 24 h of combined loading in a custom-designed test facility. From the recorded mechanical system response, characteristic parameters were evaluated to assess the performance of the system at varying climatic and mechanical conditions. These experimental results reveal effects of ambient conditions, previous loading and deformation Amplitude peaks on the system response. The proposed test methodology opens up for new performance-related approaches in durability testing.
To arrive to sustainable hydrogen-based energy solutions, the understanding of water-splitting catalysts plays the most crucial role. Herein, state-of-the-art hypotheses are combined on electrocatalytic active metal sites toward the oxygen evolution reaction (OER) to develop a highly efficient catalyst based on Earth-abundant cobalt and zinc oxides.
The precursor catalyst Zn0.35Co0.65O is synthesized via a fast microwaveassisted approach at low temperatures. Subsequently, it transforms in situ from the wurtzite structure to the layered γ-Co(O)OH, while most of its zinc leaches out. This material shows outstanding catalytic Performance and stability toward the OER in 1 m KOH (overpotential at 10 mA cm−2 ηinitial = 306 mV, η98 h = 318 mV). By comparing the electrochemical results and ex situ analyses to today’s literature, clear structureactivity correlations are able to be identified. The findings suggest that coordinately unsaturated cobalt octahedra on the surface are indeed the active centers for the OER.
Aufgrund der stark korrosiven Atmosphäre in Tunnelbauwerken kommt es aufgrund von Reinigungs- und Sanierungsmaßnahmen an Ein- und Anbauteilen aus nichtrostendem Stahl häufig zu wartungsbedingten Verkehrsbeeinflussungen und Tunnelsperrungen. Bislang ist nur eine kleine Gruppe rostfreier Edelstähle für die Verwendung in Tunnelbauwerken zugelassen. Im Sinne einer mittel- bis langfristigen Reduktion von Wartungsarbeiten besteht jedoch großes Interesse, die Einsatzmöglichkeiten alternativer nichtrostender Stähle zu erhöhen.
Um dies zu ermöglichen, entwickelten die Bundesanstalt für Materialforschung und -prüfung (BAM), gemeinsam mit dem Landesbetrieb Straßenbau NRW, in Zusammenarbeit mit der Informationsstelle Edelstahl Rostfrei (ISER), mit Unterstützung des Edelstahlherstellers Outokumpu und der Wilhelm Modersohn GmbH & Co. KG ein Forschungsprojekt zur Auslagerung von nichtrostenden Duplexstählen in Straßentunnel. Im Oktober 2019 beteiligte sich der Landesbetrieb Straßen, Brücken und Gewässer in Hamburg und ermöglichte die Auslagerung im Elbtunnel auszuweiten.
Ziel des Projektes ist die Qualifizierung von Duplexstählen in Tunnelbauwerken um die Einsatzmöglichkeiten alternativer nichtrostender Stähle zu den bislang gebräuchlichen rostfreien Edelstählen 1.4404 und 1.4571 zu eruieren. Da Duplexstähle im Vergleich zu austenitischen Stählen über eine doppelt so hohe Festigkeit verfügen, können Bauteile schlanker konstruiert werden, wodurch Material eingespart werden kann. Neben der Wirtschaftlichkeit muss die Dauerhaftigkeit untersucht werden. Dazu wurden speziell konzipierte Wand- und Deckenracks mit unterschiedlichen metallenen Werkstoffen und Oberflächen hergestellt und in den Tunnelbauwerken montiert. Nach bestimmten Auslagerungszeiten von bis zu drei Jahren werden die Proben demontiert und auf ihr Korrosionsverhalten untersucht. Ein weiteres Ziel neben der Qualifizierung der Werkstoffgruppe sind die Reduktion der Instandsetzungs- und Wartungsmaßnahmen der Tunnelbetreiber.
Ziel des Projektes ist die Qualifizierung von Duplexstählen in Tunnelbauwerken um die Einsatzmöglichkeiten alternativer nichtrostender Stähle zu den bislang gebräuchlichen rostfreien Edelstählen 1.4404 und 1.4571 zu eruieren. Da Duplexstähle im Vergleich zu austenitischen Stählen über eine doppelt so hohe Festigkeit verfügen, können Bauteile schlanker konstruiert werden, wodurch Material eingespart werden kann. Neben der Wirtschaftlichkeit muss die Dauerhaftigkeit untersucht werden. Dazu wurden speziell konzipierte Wand- und Deckenracks mit unterschiedlichen metallenen Werkstoffen und Oberflächen hergestellt und in den Tunnelbauwerken montiert. Nach bestimmten Auslagerungszeiten von bis zu drei Jahren werden die Proben demontiert und auf ihr Korrosionsverhalten untersucht. Ein weiteres Ziel neben der Qualifizierung der Werkstoffgruppe sind die Reduktion der Instandsetzungs- und Wartungsmaßnahmen der Tunnelbetreiber
The advantages of treating prefabricated components made of Ultra-High-Performance Concrete (UCPC) at 90 °C are largely recognized, while hydrothermal treatment at 185 °C and the corresponding saturation pressure of 1.1 MPa, in contrast, is not applied in building practice so far and was studied only by a few researchers.
In the research presented, the parameters pre-storage-time before treatment and dwell time in the autoclave were systematically varied. The results illustrate in which way compressive strength increases with the duration of treatment. Already samples which were only heated up and immediately cooled down show an increase in strength compared to the 28-day reference of about 10 %. After 20 h the maximum increase of about 25 % is reached. Interestingly the compressive strength of samples treated very long hardly decreases. It can be therefore concluded that for the composition investigated the achievable mechanical strength is not severely sensitive regarding the duration of the treatment.
Also, pre-storage times before autoclaving longer than 0.5 days showed no significant impact on strength development.
The phase composition measured by XRD exhibits significant changes compared to the reference. The amount of ettringite and portlandite have vanished, the cement clinker phases are substantially decreased and hydroxylellestadite and hydrogarnet are formed as new phases. The increase in strength can be assigned to an improved pozzolanic and hydraulic reaction. Contradictory to literature, there was found no tobermorite, a mineral which is known to be susceptible for disintegration at Long autoclaving duration. This explains why no significant strength loss appeared.
The low tensile strength of cement-based materials can be improved by the addition of fibres. In a joint research project, an industrial partner designed special coatings for polymer and carbon fibres by integrating surfactants and hydrophilic compounds. Aim of the developed functionalization was to ensure an even coverage of the fibre surfaces and to anchor them chemically in the cement-based matrix. Task of the BAM was to quantify the effect of the improved bond. In a first step a workable mortar adjusted to the strength of the tested fibres was developed and the fibre distribution assessed by light microscopy and computed tomography. To test the new coating for its efficiency to prevent cracking during hardening and to improve the loadbearing behaviour new test setups were developed or existing methods were adjusted.
The experiments showed that the functionalization leads to a reduction of the crack area measured after the exposure of the wet mortar to strong drying conditions in the wind channel. Regarding the Efficiency to mitigate shrinkage cracks the functionalisation turned out to be more efficient for fibres made from polyacrylonitrile (PAN) than for carbon fibres. An improvement of the tensile strength after cracking of the cementitious matrix could only be documented for the coated carbon fibres. It could be quantified, however, only in the three-point bending tests because the fibres turned out to be too brittle for the applied single fibre pull-through test.
The advantages of treating prefabricated components made of Ultra-High-Performance Concrete (UCPC) at 90 °C are largely recognized, while hydrothermal treatment at 185 °C and the corresponding saturation pressure of 1.1 MPa, in contrast, is not applied in building practice so far and was studied only by a few researchers.
In the research presented, the parameters pre-storage-time before treatment and dwell time in the autoclave were systematically varied. The results illustrate in which way compressive strength increases with the duration of treatment. Already samples which were only heated up and immediately cooled down show an increase in strength compared to the 28-day reference of about 10 %. After 20 h the maximum increase of about 25 % is reached. Interestingly the compressive strength of samples treated very long hardly decreases. It can be therefore concluded that for the composition investigated the achievable mechanical strength is not severely sensitive regarding the duration of the treatment.
Also, pre-storage times before autoclaving longer than 0.5 days showed no significant impact on strength development. The phase composition measured by XRD exhibits significant changes compared to the reference. The amount of ettringite and portlandite have vanished, the cement clinker phases are substantially decreased and hydroxylellestadite and hydrogarnet are formed as new phases. The increase in strength can be assigned to an improved pozzolanic and hydraulic reaction. Contradictory to literature, there was found no obermorite, a mineral which is known to be susceptible for disintegration at Long autoclaving duration. This explains why no significant strength loss appeared.
During a European convention of the authorities for market surveillance (AdCO) for explosives the activities of the notified bodies are presented, putting a focus on matters concerning market surveillance.
The presentation outlined in detail, which verifications are possible
with explosives, while practical tests involving initiation of
explosives are excluded. Elements of labeling and the conclusions in
view of quality control were explained, and typical failures by
manufacturers to comply were orally described.
Permitted explosives have a tradition of many decades in Germany and had been designed to the needs of the underground coal mining in the Ruhr. In neighboring countries of Germany similar provisions were made to prevent hazards from fire damp and coal dust explosions in underground coal mines. Due to the termination of coal mining in Germany and most other European countries, also the testing facilities are disappearing. This presentation outlines the current situation of testing regimes and facilities.
Bei der Marktüberwachung im Bereich Explosivstoffe und Pyrotechnik stehen die Behörden der Länder immer wieder vor dem Problem, mit ausreichenden Kenntnissen über die Vielfalt der Produkte ausgestattet zu sein. Darüber hinaus lassen sich nur in seltenen Fällen im Rahmen der Marktüberwachung Prüfungen mit der regulären Funktion des Explosivstoffs oder der Pyrotechnik durchführen. Dadurch konzentriert sich die Überwachung vor allem auf äußere Merkmale und die Kennzeichnung. In dem Vortrag werden anhand von Beispielen die technischen und rechtlichen Hintergründe für entsprechende Kontrollen dargestellt und mit den Erfahrungen der an der Marktüberwachung Beteiligten abgeglichen.
Several decades have passed since the initial drafting of the European standards for explosives subject to European Directive 2014/28/EU, and this field as experienced some substantial technical innovations. While at the turn of the millenium the concept of electronic detonators had just been conceived, and it is mentioned in a Technical Specification, today electronic detonators exist in many variants, also regarding communication means between shotfirer and the detonating cap. Questions regarding safe functioning and prevention of inadvertent ignition have to be asked in a quite different way, where delicate electronic circuits are used, and where information is transmitted by radio waves. In addition, the safety of functioning is partly found in software components and the corresponding standards need to be reviewed thoroughly on these grounds.
A different but in recent times more and more popular technology, is the on-site production of explosives, being mostly emulsion explosives, ANFO, or combined products. Also here software in the machinery is starting to play an important role. The on-site produced explosive must fulfil safety requirements and has to be, in addition, quality controlled. This cannot solely be left to the hopefully proper design of the software and machinery, but needs to be made accessible to verification. Since this area seems broader in approach, it is not going to be addressed by a new standard. The state of the art technology shall be described in a Technical Specification with a perspective from requirements of the above mentioned European Directive.
Since the early drafting of the European standards for civil explosives, harmonised under directive 93/15/EEC and 2014/28/EU, blasting technology has developed notably. This is particularly evident for electronic detonators and electronic firing systems, and the EU commission agreed to initiate a standardisation initiative, also noting that the currently existing document on electronic detonators is “only” a Technical Specification (CEN/TS). This paper addresses the current activities in the area of standardisation. The EU is about to launch a formal standardisation request to cover the most recent technological developments not addressed by the current standards. The request would also include various adjustments of references to the new Directive for civil explosives, and in addition the task of developing a Technical Specification for on-site mixed explosives and corresponding manufacturing units. The latter has been included to address the nowadays frequently found mobile production on the basis of ammonium nitrate prills or emulsions.
Ultra high performance concrete (UHPC) is characterised by its high compressive strength of more than 150 MPa and its high durability. Due to thermal treatment at 90°C a strength comparable to the 28-days-strength can be achieved immediately after the treatment and in some cases can be even further increased up to 30 %. The explanations for the increase in strength are the accelerated hydration of the clinker minerals and the intensified pozzolanic reaction contributing to a denser microstructure and hence, a high performance in compressive strength.
Former research shows that thermal treatment can lead to inhomogeneities in form of a visible zonation within the cross-section. The width of the margin increases with shorter pre-storage time before the thermal treatment and with omitting protective measures against desiccation during the treatment. Specimens exhibiting a zonation typically show a lower compressive strength compared to the undisturbed reference whereas changes in chemistry, mineral content and microstructure were not reported in detail.
In this study the zonation of thermally treated UHPC is investigated with respect to its chemistry, mineral composition and microstructure to allow predictions on durability and strength development. Measurements show a change in pore sizes, minerals phase composition and element distribution leading to the visible zonation and weaker bending tensile strength compared to the reference.
Ultra high performance concrete (UHPC) is characterised by its high compressive strength of more than 150 MPa and its high durability. Due to thermal treatment at 90°C a strength comparable to the 28-days-strength can be achieved immediately after the treatment and in some cases can be even further increased up to 30 %. The explanations for the increase in strength are the accelerated hydration of the clinker minerals and the intensified pozzolanic reaction contributing to a denser microstructure and hence, a high performance in compressive strength.
Former research shows that thermal treatment can lead to inhomogeneities in form of a visible zonation within the cross-section. The width of the margin increases with shorter pre-storage time before the thermal treatment and with omitting protective measures against desiccation during the treatment. Specimens exhibiting a zonation typically show a lower compressive strength compared to the undisturbed reference whereas changes in chemistry, mineral content and microstructure were not reported in detail.
In this study the zonation of thermally treated UHPC is investigated with respect to its chemistry, mineral composition and microstructure to allow predictions on durability and strength development. Measurements show a change in pore sizes, minerals phase composition and element distribution leading to the visible zonation and weaker bending tensile strength compared to the reference.
Lead isotopes are a well-established tool to trace the geographic origin of samples and artefacts in archaeology and geochemistry. In archaeology, lead isotopes are often applied to gain information on the provenance of the used ores especially in lead and silver artefacts. The assignment of a specific and unambiguous provenance in most cases is not possible or at least hindered due to several limitations such as ore deposits overlapping in their lead isotopic composition, a large spread within one ore deposit or a missing overlap with known mining sites. Such difficult cases can only be solved by using information from sources being independent of the isotope data. This information can be of chemical nature such as concentrations of key elements or they can be of archaeological nature such as cultural or trade route information.Within this study, we combined lead isotope data of ores and artefacts with silver mass fractions in the ore deposits, Au/Ag-ratios in ores and artefacts and finally archaeological Information on the cultural context in the Mediterranean and Anatolian Region. This approach enabled us to significantly reduce the potential number of mining regions. Finally, the potential sources could be narrowed down to the three remaining locations the Central Taurus, Arap Dağ and the Eastern Troad. Beneath these three locations, the Central Taurus shows the highest probability for the geographic origin of the galena which has been used to create the Trojan silver artefacts.
What isotopes can do...
(2019)
A seamless pipe made of AISI 321 stainless steel represented a part of a transportation Pipeline system for hydrogen-containing hot gas in a hydrocarbon cracking unit. After a service period of approximately 21 months, a segment of such pipe demonstrated the cracks, causing leakage and respective fire. For clarification of a failure root cause, various metallurgical investigations combined with numerical simulations have been applied. The results revealed that the rupture of seamless pipe was evidently influenced by hydrogen assisted cracking (HAC). An increased susceptibility of the alloy to HAC had to be attributed to its sensitive microstructure which was related to the occurrence of slip bands with a high quantity in austenite grains, particularly in the specific region underneath the outer wall surface. In addition, the intensity of restraint resulting from the T-joint weld configuration caused respectively higher triaxial stresses in the confined area on the outer wall surface where the crack started. The numerical simulations of hydrogen diffusion revealed that a uniform hydrogen concentration profile over the pipe wall thickness was reached when the service period was more than 20 months. This duration agreed well to the timeto-failure of the actual component. Considering additionally that the final stage of rupture by overload was preceded by severe HAC, as confirmed by the respective intergranular fracture topography.
Rapid cooling rates and steep temperature gradients are characteristic of additively manufactured (AM) parts and important factors for residual stress formation which have implications on structural integrity. This study examined the influence of heat input on the distribution of residual stresses in two prisms produced by laser powder bed fusion (L-PBF) of austenitic stainless steel 316L.
The layers of the prisms were exposed using two distinct helix scanning strategies: one scanned from the centre to the perimeter and the other from the perimeter to the centre. Residual stresses were characterised at one plane perpendicular to the building direction at half of its build height using neutron diffraction. In addition, the defect distribution was analysed via micro X-ray computed tomography (µCT) in a twin specimen.
Both scanning strategies reveal residual stress distributions typical for AM: compressive stresses in the bulk and tensile stresses at the surface. However, temperature gradients and maximum stress levels differ due to the different heat input. Regarding the X-ray µCT results, they show an accumulation of defects at the corners where the laser direction turned through 90°.
The results demonstrate that neutron diffraction and X-ray µCT can be successfully used as non-destructive methods to analyse through-thickness residual stress and defect distribution in AM parts, and in the presented case, illustrate the influence of scanning strategies. This approach contributes to deeper assessment of structural integrity of AM materials and components.
µCT is used to validate the capability of online monitoring for in-situ detection of defects during the L-PBF build process, which is a focus of the TF project ProMoAM.
Our first experiments show that online monitoring using thermography and optical tomography cameras are able to detect defects in the built part. But further research is needed to understand root cause of the correlation.
The Influence of the Temperature Gradient on the Distribution of Residual Stresses in AM AISI 316L
(2019)
Steep temperature gradients and solidification shrinkage are the main contributors to the formation of residual stresses in additively manufactured metallic parts produced by laser beam melting. The aim of this work was to determine the influence of the temperature gradient.
Diffraction results show a similar pattern for both specimens, indicating the shrinkage to be more dominant for the distribution of residual stresses than the temperature gradient. Thermography results imply that a higher energy input result in higher compressive residual stresses in the bulk.
Additive manufacturing is no longer just used for the production of prototypes but already found its way into the industrial production. However, the fabrication of massive metallic parts with high geometrical complexity is still too time-consuming to be economically viable. The combination of the powder bed-based selective laser melting process (SLM), known for its geometrical freedom and accuracy, and the nozzle-based laser metal deposition process (LMD), known for its high build-up rates, has great potential to reduce the process duration. For the industrial application of the SLM-LMD hybrid process chain it is necessary to investigate the interaction of the processes and its effect on the material properties to guarantee part quality and prevent component failure. Therefore, hybrid components are manufactured and examined before and after the heat treatment regarding the microstructure and the hardness in the SLM-LMD transition zone. The experiments are conducted using the nickel-based alloy Inconel 718.
Ball mass is an important parameter that is known to have an influence on the outcome of a mechanochemical reaction induced by ball-milling. A standard way of modifying the ball mass is to change the size of the ball made of the same material. In this case, however, a change in mass is accompanied by a simulatneous change in the ball size. It is therefore not possible to disentangle the effects of mass and Surface area in these cases. In the present work we report the results of experiments with specially designed and manufactured balls in which (1) milling ball mass is held constant, but their size differs, and (2) the ball mass is altered, with the diameter of the milling ball being held constant. Using the cocrystallisation of theophylline + nicotinamide as a case study it was found that both diameter and ball mass play crucial roles in determining the rate of a mechanochemical reaction. For comparison, we have also used milling balls with the same size (different mass), and others with the same mass (different size) made of different materials, as would be “traditional”. It was found that, despite having the same size, the lightest milling ball (nylon) was the most efficient in initiating the co-crystallisation, presumably due to the sorption of EtOH. Hence, the results of this manuscript also demonstrate how milling ball material can in fact be the most influential parameter, and potentially counterintuitive to classical mechanics.
Im Vergleich zu anderen Proteinen ist die Identifizierung von Antikörpern anhand ihrer Sequenz zum Beispiel mittels "peptide mass fingerprinting" schwierig. Da die Sequenzinformation eines Antikörpers aufgrund der hypersomatischen Mutation während der Affinitätsreifung nicht im Genom eines Organismus gespeichert ist, kann die Aminosäuresequenz nicht auf einfachem Weg der DNA-Sequenzierung gewonnen werden. Das ist nur in seltenen Fällen möglich, wenn dem Endanwender der Zellklon der Antikörper-produzierenden Zelle zugänglich ist. Eine Sequenzierung auf Protein-Ebene ist sehr aufwändig und teuer und wird daher fast nie für die Charakterisierung von analytischen Antikörpern verwendet. Der Mangel an Validierung dieser analytischen Antikörper, die bei Experimenten verwendeten werden, löst aber eine Reihe Probleme aus, die die Wiederholbarkeit dieser Experimente schwierig und in einigen Fällen unmöglich macht. Das sorgt jährlich für verschwendete Forschungsgelder in Milliardenhöhe und hindert den wissenschaftlichen Fortschritt.
Ziel der vorliegenden Arbeit war die Entwicklung einer einfachen und schnellen Methode, die es trotzdem ermöglicht, die Identifikation von Antikörpern sicherzustellen. Dazu wurde eine Methode basierend auf dem "peptide mass fingerprinting" gewählt. Das Problem der unbekannten Aminosäuresequenz der Antikörper wurde gelöst, indem lediglich die Peptidmuster der entstehenden Fingerprint-Spektren zur Identifikation herangezogen wurden. MALDI wurde dabei als Ionisationsmethode für die Massenspektrometrie gewählt, da die resultierenden Spektren im Gegensatz zu ESI-MS einfach auszuwerten sind. Auch kann auf eine vorige Trennung der Peptide mittels LC verzichtet werden, was zusätzlich Analysenzeit spart. Für die Proteinspaltung wurde eine simple saure Hydrolyse mittels Ameisensäure gewählt. Im Vergleich zum herkömmlichen Trypsin-Verdau konnten auf zeitraubende Arbeitsschritte wie Denaturierung, Reduktion und Alkylierung der Antikörper verzichtet werden. Die Hydrolyse mittels Ameisensäure wurde bisher nur auf kleine und mittelgroße Proteine angewendet, sodass im ersten Teil dieser Arbeit mehrere Schritte optimiert wurden bevor zufriedenstellende Fingerprint-Spektren von Antikörpern erhalten wurden.
Diese DIN SPEC legt ein Verfahren für die Prüfung von unverstärkten und partikel- und kurzfaserverstärkten Kunststoffen mittels Zug-Druck-Schubprüfung fest. Dieses Verfahren findet Anwendung zur Bestimmung der Schwingfestigkeit im Bereich von 103 bis 107 Schwingspielen und der Nachgiebigkeiten unter statischer Belastung sowie der Zugfestigkeit. Alle Beanspruchungen und berechneten Größen sind nennspannungs-basiert.
Grundsätzlich besteht bei Rohrprobekörpern auch die Möglichkeit eine Beanspruchung in Längs- und in Umfangsrichtung durch Innendruck zu erzeugen. Dies wird in dieser Spezifikation nicht berücksichtigt, um die Anwendung überschaubar zu halten. Bei Rohrproben mit ausgeprägter Querschnittsverkleinerung (z. B. der Prüfkörper Typ B), entsteht eine Umfangsspannung auch aufgrund einer Zugkraft (siehe Anhang C). Die Umfangsspannung muss dann mittels FEA lokal berechnet werden.
Das Verfahren gilt für rohrförmige Prüfkörper deren spezifische Form den Anforderungen der Werkstoff-prüfung und bei Kurzfaserverstärkung einer hohen Vorzugsausrichtung in Probenlängsrichtung genügen.
Diese DIN SPEC gilt nicht für endlosfaserverstärkte Kunststoffe. Wegen der vollkommen unterschiedlichen Fertigungstechnologien und der zu erwartenden hohen Prüflasten, sind hier die Anforderungen an die Prüfkörpergeometrie gesondert zu betrachten. Es wird nicht zielführend sein, beide Werkstoffklassen in einer Norm zu behandeln.
An effective method for evaluating the fatigue strength of thick unidirectional composite laminates of wing spar caps has been presented here. A typical width-tapered bending specimen has been developed for a four-point loading set up. Static and fatigue loading was performed at a load ratio R = -1. The complex stress state has been investigated numerically by finite element analysis. Finally, the concept is proven experimentally on specimens made of pultruded fibre rods.
The fatigue behavior of the continuously tapered width by water Jet cutting has been compared to discrete tapering via rod-drop. The new method enables a screening of material fatigue behavior caused by normal and shear loading.
The common fatigue life certification of aircrafts according to the certification Standards 23 and 25 follows a building block approach. Static tests at room temperature as well in humid and high temperature conditions are done on the coupon level. Additionally, a full-scale static and fatigue test must be performed on the complete airframe (minimum on the fuselage together with the wing). For each type-certificate the complete building block approach test program must be performed.
Traditionally in Germany, the certification of sailplanes (Certification Standard 22) follows rather a family concept. A shared data base was created over the last 50 years based upon a large number of material testing. In addition to static tests at room temperature and hot-humid conditions, fatigue tests are also done on the coupon level. Additional static and fatigue tests were done on complex structures such as spar-beams, fuselages and full-scale wing structures. However, for each type-certificate, only static tests should be performed in full-scale. This concept is determined by the certification memorandum CM-S-006 “Composite Lightweight Aircraft” 2017.
The presentation was given as an introduction to the discussion about the future expectations and developments of the EASA concerning the type-certification of lightweight aircrafts according to CS22 at the OSTIVE Sailplane Development Panel Meeting at the EASA in Cologne on the 11th of October 2019.
Der Fachbereich Mechanik der Polymerwerkstoffe befasst sich mit der Charakterisierung der mechanischen Eigenschaften und der Degradation von Polymeren und Faserverbundwerkstoffen, die in hochbeanspruchten, sicherheitsrelevanten Konstruktionen wie jenen des Flugzeugbaus, des Automobilbaus und der Windenergie-Industrie eingesetzt werden. Auch die Analyse der chemischen und physikalischen Eigenschaften von Polymeren zählt zu unserem Aufgabenbereich.
Das Spektrum reicht von der statischen Festigkeit über die Betriebsfestigkeit, die Messung bruchmechanischer und viskoelastischer Parameter bis hin zur Formulierung molekularer Schädigungsmechanismen.
Even for the basic measurements of material data for design and engineering of composite structures there is a need to upgrade standards. With a new shear frame test rig more precise values can be obtained.
With advanced methods in the research on the fatigue behaviour of FRP it was found a load level of infinite life for GFRP and CFRP. This is in the range of typical strain values of airliners and rotor blades in normal operation.
Statistically the mean time between damage events on rotor blades is 6 years (Deutscher Windenergie Report 2006). Due to imperfection in the production the shell structures get cracks after a few years fare before the designed life time. A shell test rig was built at BAM for efficient research on the effects of defects in production.
Test blades of ~10m are an efficient way for SHM research and evaluation of NDT-methods and blade geometry.
Statistically the mean time between damage events on rotor blades is 6 years (Deutscher Windenergie Report 2006). Due to imperfection in the production the shell structures get cracks after a few years fare before the designed life time. A shell test rig was built at BAM for efficient research on the effects of defects in production.
In-situ and ex-situ NDT give a better understanding from degradation processes in composite materials.
With advanced methods in the research on the fatigue behaviour of FRP it was found a load level of infinite life for GFRP and CFRP. This is in the range of typical strain values of airliners and rotor blades in normal operation.
Due to the fibre-composite nature NDT techniques have to be suitable to a wide length scale to image micro cracking as well as bigger defects. Therefore different techniques have to be applied and developed.
Fiber reinforced polymers (FRPs) are a well established material in lightweight applications, e.g. in automotive, aerospace or wind energy. The FRP components are subjected to multiaxial mechanical as well as hygrothermal loads. Common operation temperatures are in the range of 213 K and 373 K (-60 °C and 100 °C) at a relative humidity of 10% to 90%. In spacecraft applications, the environmental conditions are even more extreme. However, the correlation between multiaxial mechanical loading and harsh environment conditions have to-date not been investigated in detail. The project aims to investigate the fatigue behavior of FRPs dependent on multiaxial mechanical loading, temperature, and humidity. Extensive experimental testing is performed on flat plate and cylindrical tube specimens, accompanied by numerical and analytical calculations.
The church of Koszewko (Poland) is a brick building edified in the 15th century built on cobblestone foundations. There are five windows in the sanctuary. Three of them enclose heraldic panels from the Küssow’s family from the 15th century which are surrounded with Goethe glass from the 18th century to complete the windows. The colored heraldic panels are strongly damaged and corroded with massive paint layer losses, glass- and leadbreakages. Those medieval glass fragments have been shortly discovered and are of particular interest for Poland since only few medieval glazing have been conserved.
The damages as well as the glass compositions have been investigated with ESEM/EDX. Two categories of medieval glass compositions have been identified. The blue glass is particularly sensible to corrosion because of his high content in K2O. The colorless and the red glass samples belong to a stable glass type. Due to the thickness of the gel layer, it is easy to see that the degradation is strongly proceeded. The protection of those medieval stained-glass panels is absolute necessary.
The medieval panels have been restored and surrounded from a copper frame. Then they have been fixed on the wood frame in the church. The exterior glazing has been closed with a panel of Goethe glass. The gap between the Goethe- and the medieval glass is about 3 cm. The Goethe glass panel has been stabilized with a film based on polyester to protect the medieval glasses against any damages. In this way, a low cost protective glazing has been installed for a long-term conservation of each medieval stained-glass panels. The climate measurements over the period of one year on the restored windows are in process. The temperature and the relative humidity are recorded in the church interior, in the gap between the original and the Goethe glass and outdoors.
19th and 20th centuries glass paint layers consist of a colour body and a colourless lead silicate flux, in which borax or boric acid was added as further component to improve the paint ability and to reduce the firing temperature for multiple layers of paint. Model glasses were used in laboratory tests to investigate the stability of glass paints with additions of boron oxide. To determine boron in paint layers, a LIBS-system with pulsed NdYAG-laser was used.
In this work, a novel boehmite (BA)-embedded organic/inorganic nanocomposite coating based on cycloaliphatic epoxy oligosiloxane (CEOS) resin was fabricated applying UV-induced cationic polymerization. The main changes of the material behavior caused by the nanofiller were investigated with regard to its photocuring kinetics, thermal stability, and glass transition. The role of the particle surface was of particular interest, thus, unmodified nanoparticles (HP14) and particles modified with p-toluenesulfonic acid (OS1) were incorporated into a CEOS matrix in the concentration range of 1–10 wt.%. Resulting nanocomposites exhibited improved thermal properties, with the glass transition temperature (Tg) being shifted from 30 °C for unfilled CEOS to 54 °C (2 wt.% HP14) and 73 °C (2 wt.% OS1) for filled CEOS. Additionally, TGA analysis showed increased thermal stability of samples filled with nanoparticles. An attractive interaction between boehmite and CEOS matrix influenced the curing. Real-time infrared spectroscopy (RT-IR) experiments demonstrated that the epoxide conversion rate of nanocomposites was slightly increased compared to neat resin. The beneficial role of the BA can be explained by the participation of hydroxyl groups at the particle surface in photopolymerization processes and by the complementary contribution of p-toluenesulfonic acid surface modifier and water molecules introduced into the system with nanoparticles.
Thermosetting materials are gaining increasing attention in many structural composite applications. However, the incorporation of inorganic nanoparticles (NPs) into polymer matrix is a promising approach to enhance their functional characteristics, and thus, to enable the development of thermosets advanced application. It has been shown that Boehmite Alumina (BA) used as nanofillers can improve different parameters of polymers. This NPs can be easily tailored enabling desirable interactions with a big range of polymers. However, the overall effect of nanofiller depends on many factors, therefore, making it hard to predict the resulted performance of nanocomposites. In the current contribution we would like to discuss the impact of Boehmite NPs on two different epoxy resin nanocomposite systems with the focus on the possible influence mechanisms of this nanofiller.
As the first system, UV curable Cycloaliphatic-Epoxy Oligosiloxane (CEOS) resin/Boehmite nanocomposites were investigated by FTIR, TGA, DSC and T-SEM. It was observed that incorporation of BA leads to the reinforcement of glass transition (Tg) and overall thermal stability indicating the attractive interactions between BA and CEOS network. In addition, an increase in epoxy conversion of CEOS was concluded for nanocomposites assuming that particles are involved in UV polymerisation processes.
The second epoxy/Boehmite nanocomposite is based on the bisphenol-A-diglycidyl ether (DGEBA) cured with methyl tetrahydrophtalic acid anhydride (MTHPA). Thermomechanical as well as nanomechanical properties of this material were investigated by DMTA and IR spectroscopy and the advanced Intermodulation AFM, respectively. In contrast to the first system, it was found that BA leads to a decrease of Tg and crosslink density of the polymer while the young’s modulus of the composite and local stiffness of polymer matrix increase significantly.
As a result, the versatile role of Boehmite was detected depending on the investigated systems. Based on the obtained results, the parameters indicating property-efficient epoxy/Boehmite system are suggested.