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)
High heat input leads to grain coarsening and softening in WM and HAZ; the tensile strength is reduced. Low heat input leads to inadmissible hardening in the WM; the impact strength is reduced.
The proposed t8/5-time of 3 s to 15 s could be achieved through the reduced welding velocity.
The concept of electromagnetic weld pool support system allowed single-pass welds in flat position without gravity drop-outs even for reduced welding speeds; in this way the heat input can be controlled.
The adaptation of the electromagnetic weld pool support system to laser and laser hybrid welding process can dramatically increase the potential field of application of these technologies for real industrial implementation.
Single-pass Hybrid Laser Arc Welding of Thick Materials Using Electromagnetic Weld Pool Support
(2019)
Hybrid laser-arc welding process allows single-pass welding of thick materials, provides good quality formation of joints with minimal thermal deformations and a high productivity in comparison with arc-based welding processes. Nevertheless, thick-walled steels with a thickness of 20 mm or more are still multi-pass welded using arc welding processes, due to increased process instability by increasing laser power. One limitation factor is the inadmissible formation of gravity drop-outs at the root. To prevent this, an innovative concept of electromagnetic weld pool support is used in this study. With help of such system a stable welding process can be established for 25 mm thick steel plates and beyond. Sound welds could be obtained which are tolerant to gaps and misalignment of the welded parts. The adaptation of this system to laser and hybrid laser-arc welding process can dramatically increase the potential field of application of these technologies for real industrial implementation.
The presented study deals with the performing and mechanical testing of single pass hybrid laser-arc welds (HLAW) on 25 mm thick plates made of steel grade S355J2. One of the challenges have to be solved at full penetration HLAW of thick plates is the drop formation occurring due to the disbalances of the forces acting in the keyhole and on the melt pool surface. Such irregularities mostly limit the use of high-power laser beam welding or HLAW of thick-walled constructions. To overcome this problem, an innovative concept of melt pool support based on generating Lorentz forces in the weld pool is used in this work. This method allows to perform high quality welds without sagging even for welding of 25 mm thick plates in flat position at a welding speed of 0.9 m min-1. For the obtain of full penetrated welds a laser beam power of 19 kW was needed. A high V-impact energy of up to 160 J could be achieved at the test temperature of 0 °C. Even at the most critical part in the weld root an impact energy of 60 J in average could be reached. The tensile strength of the weld reaches that of the base material. An introduce of the HLAW process with electromagnetic support of the melt pool in the industrial practice is an efficient alternative to the time- and cost-intensive arc-based multi-layer welding techniques which are established nowadays for joining of thick-walled constructions.
With global increases in clean energy demand, the natural gas is gaining in importance. Pipelines are the safest and most cost-effective way of transporting natural gas. Due to high transport volume and resulting high operation pressure, the demand for ultra-high strength steel grades such as X120 is very strong. As a result of the fact that these steels are produced by thermo-mechanical controlled processing, the welding process must be selected accordingly. Based on investigations, a high heat input such as by submerged arc welding process leads to softening in the weld metal and loss of strength whereas pure laser beam welding results in high cooling rates and deteriorate toughness of the weld metal. The objective of this research is to investigate the influence of heat input to mechanical properties of hybrid laser-arc welded pipeline steels of grade X120. Test specimens with a thickness of 20 mm could be welded without preheating in a single-pass with different welding velocities to observe the largest possible parameter window of the heat input. The achieved V-notch impact energy for hybrid laser-arc welded samples was 144±37 J at a testing temperature of -40 °C. With a tensile strength of 930±4 MPa the requirements of API 5L was achieved. To prevent gravity drop-outs at the slow welding speeds, an electromagnetic weld pool support system was used, which works contactless and is based on generating Lorentz forces. It was therefore possible to control the cooling rate in order to meet the requirements of the mechanical properties. By adapting the electromagnetic weld pool support to the laser and laser hybrid welding process, the application potential of these technologies for industrial implementation can be drastically increased.
Hybrid laser-arc welding offers many advantages, such as deep penetration, good gap bridge-ability, and low distortion due to reduced heat input. The filler wire which is supplied to the process is used to influence the microstructure and mechanical properties of the weld seam.
A typical problem in deep penetration high-power laser beam welding with filler wire and hybrid laser-arc welding is an insufficient mixing of filler material in the weld pool, leading to a non-uniform element distribution in the seam. In this study, oscillating magnetic fields were used to form a non-conservative component of the Lorentz force in the weld pool to improve the element Distribution over the entire thickness of the material. Full penetration hybrid laser-arc welds were performed on 20-mm-thick S355J2 steel plates with a nickel-based wire for different arrangements of the oscillating magnetic field. The Energy-dispersive X-ray spectroscopy (EDS) data for the distribution of two tracing elements (Ni and Cr) were used to analyze the homogeneity of dilution of the filler wire.
With a 30° turn of the magnetic field to the welding direction, a radical improvement in the filler material distribution was demonstrated. This would lead to an improvement of the mechanical properties with the use of a suitable filler wire.
The presentation summarizes our recent results on the coupled electrochemical methods for high resolution corrosion studies. The combination of Scanning Electrochemical Microscopy (SECM) and multielectrode (MMA) based real-time corrosion monitoring was presented as a new method for achieving high time resolution in local electrochemical analysis. Correlative imaging by means of Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) was demonstrated as a tool for the investigation of local corrosion processes initiated by the intermetallic particles (IMPs) on AA2024-T3 aluminium alloy.
The performance of functional coatings and adhesively joined hybrid components relies strongly on the stability of the polymer-metal interface. With the increasing utilization of multi-material structures in the automotive and aerospace industry, it is of great scientific and technical interest to understand the processes leading to interface degradation and to develop novel strategies to increase corrosion and delamination resistance.
The aim of this project is to develop thin epoxy-based films and their carbon nanofiller loaded composites on aluminium alloy AA2024-T3 as a model system and to investigate their interfacial stability under corrosive and coupled corrosive-mechanical load. Spin coating was used for the layer-by-layer deposition of poly[(o-cresyl glycidyl ether)-co-formaldehyde] and poly-(ethylenimine) bi-layers. Atomic force microscopy (AFM) results indicate a very homogeneous and dense film with low surface roughness. Carbon nanofillers were introduced either by mixing into the coating components or in between individual layers to control the separation between the carbon nanofillers and alloy surface. The film chemistry and barrier properties were characterized by means of spectroscopic and electrochemical methods, respectively. The degradation and delamination behavior of the epoxy-based films was characterized by means of in situ AFM corrosion experiments. The quantitative imaging (QI) mode allowed the observation of hydrogen-generation induced blister formation during exposure to corrosive electrolyte and how the local corrosion processes evolved with exposure time. Complementary energy dispersive X-ray spectroscopy (EDX) analysis was performed to correlate the corrosion behavior with the different intermetallic particle chemistries and distributions. The presentation will summarize our results on the effect of interface chemistry and carbon nanofiller – alloy separation on the initiation of local corrosion processes on thin film covered AA2024-T3 aluminium alloys.
In service, most materials are operated under simultaneous corrosive and mechanical load and there are very few methods capable for testing material degradation under these conditions, especially when it comes to high resolution analysis. For this purpose, in this work, a tensile module capable of uniaxial stretching and compression with up to 5 kN force was integrated into an AFM stage. The elimination of the need for sample unmounting and remounting and the resulting possibility of keeping the sample under constant mechanical load during AFM measurements not only enables a precise positioning of the area of interest but also allows for the analysis of processes in the elastic deformation regime.
This methodology was demonstrated for two case studies. Scanning Kelvin Probe Force Microscopy (SKPFM) was used as the main tool to characterize the deformation behavior. Moreover, a flexible electrochemical measurement cell was used to enable electrochemical analysis by means of electrochemical impedance spectroscopy (EIS) and Linear Sweep Voltammetry (LSV) during AFM measurements at different levels of strain. The in situ AFM results are complemented by microstructure analysis by means of electron backscatter diffraction (EBSD).
In the first case study, the deformation induced delamination of a thin organic coating on AA2024 T3 aluminium alloy was investigated as a function of alloy surface treatment. The formation of cracks in the insulating passive film enabled an early detection of deformation processes by means of SKPFM. The second case study focused on the comparison of corrosion and deformation behavior of conventional and additively manufactured 316 stainless steels. In comparison to the conventional 316 stainless steel, the effect of processing was clearly detectable on the additively manufactured material as zones of inhomogeneous potential, which also affected the initiation of local corrosion processes. The contribution will provide detailed information on the new AFM setup and summarize our results from both case studies.
Dose enhancement by gold nanoparticles (AuNP) was shown to increase the biological effectiveness of radiation damage in biomolecules and tissue. Most of the current studies focus on external beam therapy on combination with AuNP. Here we present a Monte-Carlo study (Geant4) to characterise radioactive AuNP. Radioactive 198 Au emits beta and gamma rays and is considered for applications with solid tumours. To effectively apply 198 AuNP their energy deposit characteristics have to be determined in terms of intrinsic and extrinsic properties e.g. AuNP diameter, AuNP density, and their clustering behaviour. After each decay process, the energy deposit, inelastic scattering events, kinetic energy spectrum of secondary particles within the AuNP themselves and in a spherical target volume of water up to 1 μm radius were determined. Simulations were performed for AuNP radii ranging from 2.5 nm to 20 nm radius, different cluster sizes and densities. The results show an increase of the energy deposit in the vicinity of the AuNP up to 150 nm. This effect nearly vanishes for distances up to one micron. For the case of AuNP clusters and the same activity, the enhancement of the energy deposit increases with the relative gold mass percentage and therefore can be adjusted by changing AuNP radius or clustering behaviour.
As humanity contemplates manned missions to Mars, strategies need to be developed for the design and operation of hospitable environments to safely work in space for years. The supply of spare parts for repair and replacement of lost equipment will be one key need, but in-space manufacturing remains the only option for a timely supply. With high flexibility in design and the ability to manufacture ready-to-use components directly from a computeraided model, additive manufacturing (AM) technologies appear extremely attractive. For the manufacturing of metal parts, laser-beam melting is the most widely used AM process. However, the handling of metal powders in the absence of gravity is one prerequisite for its successful application in space. A gas flow throughout the powder bed is successfully applied to compensate for missing gravitational forces in microgravity experiments. This so-called gas-flow-assisted powder deposition is based on a porous Building platform acting as a filter for the fixation of metal particles in a gas flow driven by a pressure difference maintained by a vacuum pump.
In powder bed Additive Manufacturing (AM) technologies, a part is produced by depositing and piling up thin powder layers. In each layer, the cross section of the object to build is defined by locally consolidating the powder, by sintering/melting the material (powder bed fusion technologies) or by ink jetting a binder (binder jetting technologies).
These are already leading AM technologies for metals and polymers, thanks to their high productivity and scalability. The application of these techniques to most ceramics has been challenging so far, because of the challenges related to the deposition of homogeneous powder layers when using fine powders.
In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method which enables the use of SLS/SLM and 3DP technologies for advanced ceramic materials. LSD consists in the layer-by-layer deposition of a ceramic slurry by means of a doctor blade. Each layer is deposited and dried to achieve a highly packed powder layer. The LSD offers high flexibility in the ceramic feedstock used, especially concerning material and particle size, and enables the production of parts with physical and mechanical properties comparable to pressed or slip-casted parts. In this presentation, the LSD technique will be introduced and several examples of application to porcelain, SiC and alumina products will be reported.
Powder bed -based technologies are amongst the most successful Additive Manufacturing (AM) techniques. "Selective laser sintering/melting" (SLS/SLM) and "binder jetting 3D printing" (3DP) especially are leading AM technologies for metals and polymers, thanks to their high productivity and scalability.
However, the flowability of the powder used in these processes is essential to achieve defect-free and densely packed powder layers. For standard powder bed AM technologies, this limits the use of many raw materials which are too fine or too cohesive.
This presentation will discuss the possibilities to either optimize the powder raw material to adapt it to the specific AM process, or to develop novel AM technologies which are able to process powders in a wider range of conditions.
In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method which enables the use of very fine ceramic particles. Another technology, the Gas Flow Assisted Powder Deposition, can increase the stability of the powder bed and the packing density, even in extreme conditions such as in absence of gravitational forces.
Powder bed -based technologies are amongst the most successful Additive Manufacturing (AM) techniques. "Selective laser sintering/melting" (SLS/SLM) and "binder jetting 3D printing" (3DP) especially are leading AM technologies for metals and polymers, thanks to their high productivity and scalability. In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method which enables the use of SLS/SLM and 3DP technologies for advanced ceramic materials. LSD consists in the layer-by-layer deposition of a ceramic slurry by means of a doctor blade. Each layer is deposited and dried to achieve a highly packed powder layer, which can be used for SLM or for 3DP. This technique offers high flexibility in the ceramic feedstock used, especially concerning material and particle size, and is capable of producing parts with physical and mechanical properties comparable to traditionally shaped parts. In this presentation, the LSD technique will be introduced and several examples of application to porcelain, SiC and alumina products will be reported.
The layerwise slurry deposition (LSD) has been established in the recent years as a method for the deposition of ceramic powder layers. The LSD consists in the layer-by-layer deposition of a ceramic slurry by means of a doctor blade; each layer is sequentially deposited and dried to achieve a highly packed powder layer.
The combination of binder jetting and LSD was introduced as a novel technology named LSD-print. The LSD-print takes advantage of the speed of binder jetting to print large areas, parallel to the flexibility of the LSD, which allows the deposition of highly packed powder layers with a variety of ceramic materials.
The working principle and history of the LSD technology will be shortly discussed. A theoretical background will be also discussed, highlighting advantages and drawbacks of the LSD compared to the deposition of a dry powder.
The last part of the talk will be dedicated to highlight recent results on the LSD-print of SiSiC of geometrically complex components, in collaboration between BAM and HC Starck Ceramics GmbH. Density, microstructure and mechanical properties of LSD-printed and isostatic pressed samples will be discussed and compared.
Powder bed -based technologies are amongst the most successful Additive Manufacturing (AM) techniques. "Selective laser sintering/melting" (SLS/SLM) and "binder jetting 3D printing" (3DP) especially are leading AM technologies for metals and polymers, thanks to their high productivity and scalability.
However, the flowability of the powder used in these processes is essential to achieve defect-free and densely packed powder layers. For standard powder bed AM technologies, this limits the use of many raw materials which are too fine or too cohesive.
This presentation will discuss the possibilities to either optimize the powder raw material to adapt it to the specific AM process, or to develop novel AM technologies which are able to process powders in a wider range of conditions.
In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method which enables the use of very fine ceramic particles.
The impact of polyaniline in phosphorus flame retardant ethylene-propylene-diene-rubber (EPDM)
(2019)
Usually elastomers are loaded with high amounts of flame retardants to fulfill fire safety requirements. In this study the potential char precursor polyaniline (PANI) and the established fire retardant pentaerythritol (PER) were implemented in ethylene-propylene-diene monomer rubber (EPDM). PANI and PER were used in low loadings (7 phr) and combined with two phosphorous flame retardants, Ammonium polyphosphate (APP) and a piperazine-pyrophosphate/phosphoric acid compound (FP), to boost their performance. A comprehensive study is presented, explaining the impact of PANI on curing and mechanical properties, including compensation for the plasticizer-like effect of APP in EPDM, and improved flame retardancy. In the cone calorimeter test, the combination of EPDM/FP/PANI reduced the effective heat of combustion by 20%. All nine EPDM rubber compounds were investigated with the LOI and UL 94 tests, cone calorimeter, FMVSS 302 and glow wire testing to quantify fire performance. The PANI containing EPDM rubbers, EPDM/APP/PANI and EPDM/FP/PANI outperformed the corresponding PER containing, EPDM/APP/PER and EPDM/FP/PER rubbers in various tests. Moreover, the study investigated the impact of PANI and PER on the mode of action of the phosphorus species and showed that the addition of PANI increased the amount of phosphorus in the condensed phase. To receive a broader understanding of the flame retardant mode of action of PANI in combination with APP and FP, calculations were carried out to estimate the impact of PANI on the protective layer effect.
Alkali-silica reaction (ASR) is a serious Problem concerning the deterioration of concrete. This leads to significant maintenance and reconstruction costs for concrete infrastructures all over the world. The geographical regions, which play a major role in concrete deterioration, are for example coastal Areas or in general, areas with a high air humidity/salinity due to closeness of rivers or lakes.
These exemplary results show, the application of Raman spectroscopy establishes a valuable approach for characterizing the chemical and structural composition of ASR-products. The results prove the potential to trace the kind of reaction products, developing in dependence on the aggregate and to follow up its local alteration from origin of the gel.
In this study, the optimized fabrication and evolution of the microstructure and magnetic Transition behavior of the melt-extraction LaFe11.2Si1.8 microwires have been studied. After the optimization of extraction technique (heating power 22 KW, feeding rate 30-50 mm/s, rotation velocity 1700 r/min), the content of La Fe,Si)13 phase in the as-extracted microwires was 54 wt% due to the high solidification velocity, which was increased to 85 wt% via annealing at 1373 K for 20 min. The amount of La(Fe,Si)13 phase was increased and the composition of La(Fe,Si)13 phase became more homogenized through peritectic reaction and short-distance diffusion in the microwires during annealing process. The coexistence of the nanocrystalline and amorphous structures contributed to the broad magnetic Transition temperature range of the as-extracted and annealed microwires. The annealed microwires exhibited a second-order magnetic transformation behavior and showed a maximum magnetic entropy Change jDSMjmax of 6.2 J/kgK and working temperature interval of 36.0 K under a magnetic field of 20 kOe.
A discussion is provided on demands that must be met in order to apply fracture mechanics to the determination of overall fatigue lifetime and strength, i.e., S-N curves and fatigue limits. These comprise the determination of the cyclic crack driving force for all stages of fatigue crack propagation, in particular for the short crack stage where the crack driving force has to be determined for elastic-plastic deformation and the gradual build-up of the crack closure phenomenon. Special emphasis is put on a fatigue damage relevant specification of the initial crack size. Different approaches in the literature are discussed. Another important aspect is the adequate treatment of multiple crack propagation. Finally, the discussion is illustrated by an example of a butt weld made of a medium strength steel.
This book provides a comprehensive and thorough guide to those readers who are lost in the often-confusing context of weld fatigue. It presents straightforward information on the fracture mechanics and material background of weld fatigue, starting with fatigue crack initiation and short cracks, before moving on to long cracks, crack closure, crack growth and threshold, residual stress, stress concentration, the stress intensity factor, J-integral, multiple cracks, weld geometries and defects, microstructural parameters including HAZ, and cyclic stress-strain behavior. The book treats all of these essential and mutually interacting parameters using a unique form of analysis.
According to the definition of the ASM handbook [1,3], a defect is "an imperfection. that can be shown to cause failure by a quantitative analysis and that would not have occurred in the absence of the imperfection". The topic of the present three-part review is a discussion of defects which can cause failure in cyclically loaded structures. The features discussed comprise material defects such as non-metallic inclusions, pores or micro-shrinkages, etc. and geometric defects such as surface roughness and secondary notches which have their origin in manufacturing, and defects such as surface damage due to scratches, impact events or contact fatigue as well as corrosion pits which arise in service. In this first part, the discussion is prefaced by an introduction to basic aspects which are essential for a deeper understanding of the characteristics and mechanisms how the defects influence fatigue crack initiation and propagation. These include the life cycle of a fatigue crack from initiation up to fracture, crack arrest, multiple crack initiation and coalescence, and the material and geometrical properties affecting these.
This third part of the review on defects as root cause of fatigue failure addresses cavities (pores, micro-shrinkages, unmelted regions), defective microstructures and microcracks as material defects and defects due to local damage during manufacturing, service and maintenance such as dents, scratches and localized corrosion. In addition, damage due to contact fatigue and the effect of surface roughness are discussed in the context of fatigue failure. Also addressed is the competition between different kinds of defects in controlling the initiation and early growth of fatigue cracks.
Defects as a root cause of fatigue failure of metallic components. II: Non-metallic inclusions
(2019)
This second part of the review on defects as root cause of fatigue failure comprises the origin, the nature and the effects of non-metallic inclusions. Topics addressed are the different kinds of inclusions formed during the manufacturing process, various types of mis-match causing local stresses and, as a consequence, fatigue crack initiation, and effects of characteristics such as size, morphology, localization, spatial distribution and orientation of the defects on the fatigue behavior. Methods for inclusion counting and sizing are discussed along with statistical aspects necessary to be considered when evaluating structural components.
The paper provides an overview on material defects which may serve as fatigue crack initiation sites and can cause final fatigue failure of a component. These comprise nonmetallic inclusions in Steel and aluminum alloys, cavities such as pores, micro-shrinkages and un-welded regions in cast, sinter and additively manufactured alloys, graphite nodules, shrinkages and other items in modular cast iron, regions of defective microstructure, microcracks and secondary notches such as undercuts and surface roughness. Besides their origin, the effect and mechanisms on fatigue crack initiation and propagation are discussed.
The considerations are proceeded and accompanied by a Brief discussion of some Basic aspects such as the stages of crack propagation along their length scale, the overcoming of crack arrest and the question when a secondary notch can be treated as a crack.
The presentation provides a discussion and damage tolerant assessment of metallic AM components. In the focus are problems of the determination of representative material data, the effect of material defects and residual stresses. Starting with the actual state-of-the-art in the field, options and possibilities of a damage tolerant design for AM are discussed.
Der Vortrag behandelt in grundsätzlicher weise die Anwendung bruchmechanischer Methoden auf die rechnerische Ermittlung der Wöhlerkurve. Dabei werden die Besonderheiten des Kurzrisswachstums (Notwendigkeit der elastisch-plastischen Beschreibung der zyklischen Rissspitzenbelastung, gradueller Aufbau des Rissschlißphänomens) ebenso diskutiert wie das Problem des Mehrfachrissewachstums und Rissarrest. Die Ausführungen werden an einem Beispiel illustriert.
Der Vortrag thematisiert die Behandlung von Schweißeigenspannungen bei der Auslegung geschweißter Bauteile. Ausgehend von Fragen der Klassifizierung unterschiedlicher Typen von Eigenspannungen wird auf Fragen der Behandlung von Primär- und Sekundärspannungen, der Ermittlung und Aussagefähigkeit von Eigenspannungs-Tiefen-Profilen und der Stabilität der Eigenspannungen bei zyklischer Beanspruchung eingegangen. Neben der Auslegung auf Bruch wird die Beschreibung der Ermüdungsrissausbreitung bei Vorhandensein von Eigenspannungen diskutiert, wobei neben der klassischen Langrissbruchmechanik auch Besonderheiten der Kurzrissbruchmechanik angesprochen werden.
Spherical mesoporous bioactive glasses in the silicon dioxide (SiO2)-phosphorus pentoxide (P2O5)–calcium oxide (CaO) system with a high specific surface area of up to 300m2/g and a medium pore radius of 4 nm were synthesized by using a simple one-pot surfactant-assisted sol–gel synthesis method followed by calcination at 500–700°C. The authors were able to control the particle properties by varying synthesis parameters to achieve microscale powders with spherical morphology and a particle size of around 5–10 mm by employing one structure-directing agent. Due to a high Calcium oxide content of 33·6mol% and a phosphorus pentoxide content of 4·0mol%, the powder showed very good bioactivity up to 7 d of immersion in simulated Body fluid. The resulting microspheres are promising materials for a variety of life science applications, as further processing – for example, granulation – is unnecessary. Microspheres can be applied as materials for powder-based additive manufacturing or in stable suspensions for drug release, in bone cements or fillers.
In diesem Verbundvorhaben werden standardisierte Messverfahren für hybride Gemische erarbeitet, die der Bestimmung sicherheitstechnischer Kenngrößen des Explosionsschutzes dienen. Unter einem hybriden Gemisch wird dabei ein mehrphasiges System aus Brenngas oder brennbarem Dampf, sowie Luft und brennbarem Staub verstanden. Die Veröffentlichung der Ergebnisse erfolgt in einem Abschlussbericht und als DIN-Spezifikation (DIN SPEC). Diese DIN SPEC versetzt Prüfinstitute und Industrie in die Lage, Explosionsgefahren beim Betrieb technischer Anlagen mit hybriden Gemischen einzuschätzen und damit Prozesse sowohl sicherer als auch effizienter zu steuern. Dieses Projekt wird im Rahmen des WIPANOProgramms (Wissens- und Technologietransfer durch Patente und Normen) vom BMWi gefördert.
In diesem Verbundvorhaben werden standardisierte Messverfahren für hybride Gemische erarbeitet, die der Bestimmung sicherheitstechnischer Kenngrößen des Explosionsschutzes dienen. Unter einem hybriden Gemisch wird dabei ein mehrphasiges System aus Brenngas oder brennbarem Dampf, sowie Luft und brennbarem Staub verstanden. Die Veröffentlichung der Ergebnisse erfolgt in einem Abschlussbericht und als DIN-Spezifikation (DIN SPEC). Diese DIN SPEC versetzt Prüfinstitute und Industrie in die Lage, Explosionsgefahren beim Betrieb technischer Anlagen mit hybriden Gemischen einzuschätzen und damit Prozesse sowohl sicherer als auch effizienter zu steuern. Dieses Projekt wird im Rahmen des WIPANOProgramms (Wissens- und Technologietransfer durch Patente und Normen) vom BMWi gefördert.
In this joint project, standardized measurement methods for hybrid
mixtures are developed, which serve to determine safety
characteristics for explosion protection.
A hybrid mixture is a multi-phase System consisting of fuel gas or
vapor, as well as air and flammable dust. This combination can occur
for instance in drying processes or during heterogenous reaction
processes.
Superglassy polymers with a large fractional free volume have emerged as novel materials with a broad range of applications, especially in the field of membrane separations. Highly permeable addition-type substituted polynorbornenes with high thermal resistance and chemical stability are among the most promising materials. The major obstacle for extending the practical membrane application is their strong tendency to physical aging, leading to a partial decline in their superior transport performance over time. In the present study, broadband dielectric spectroscopy with complementary X-ray scattering techniques were employed to reveal changes in microporous structure, molecular mobility, and conductivity by systematic
comparison of two polynorbornenes with different numbers of trimethylsilyl side groups. Their response upon heating (aging) was compared in terms of structure, dynamics, and charge transport behavior. Furthermore, a detailed analysis of the observed
Maxwell−Wagner−Sillars polarization at internal interfaces provides unique information about the microporous structure in the
solid films. The knowledge obtained from the experiments will guide and unlock potential in synthesizing addition-type polynorbornenes with versatile properties.
Polymers of Intrinsic Microporosity (PIMs) of high performance have developed as materials with a wide application range in gas separation and other energy-related fields. Further optimization and long-term behavior of devices with PIMs require an understanding of the structure-property relationships including physical aging. In this context the glass transi-tion plays a central role, but with conventional thermal analysis a glass transition is usually not detectable for PIMs be-fore their thermal decomposition. Fast scanning calorimetry provides evidence of the glass transition for a series of PIMs, as the time scales responsible for thermal degradation and for the glass transition are decoupled by employing ultrafast heating rates of tens of thousands K s-1. The investigated PIMs were chosen considering the chain rigidity. The estimated glass transition temperatures follow the order of the rigidity of the backbone of the PIMs.
Polymeric membranes represent a low-cost, energy efficient solution for gas separation. Recently polymers of intrinsic microporosity (PIMs) have emerged as prestigious membrane materials featuring a large concentration of pores smaller than 1 nm, a BET surface area larger than 700 m2/g and high gas permeability and selectivity. Unusual chain structure combining rigid segments with sites of contortion gives rise to the intrinsic microporosity. However, this novel class of glassy polymers are prone to pronounced physical aging. The initial microporous structures approach a denser state via local small scale fluctuataions, leading to a dramatic reduction in the gas permeabilities. For the first time, dielectric relaxation spectroscopy with state-of-the-art high-resolution analyzers was employed to investigate three representative PIMs with a systematic change in chain rigidity: PIM-EA-TB 〉 PIM-1 〉 PIM-MDPH-TB. The molecular mobility, the charge transport and their response upon heating (aging) in the polymers were measured in a broad temperature range through isothermal frequency scans during different heating / cooling cycles. Multiple dielectric processes following Arrhenius behavior were observed for the investigated polymers. Local fluctuations, Maxwell-Wagner-Sillars (MWS) polarization and structural relaxation phenomena were discussed and attempted to be correlated with the structural features of PIMs. Moreover, all PIMs showed conductivity in the glassy state. The significant increase in the conductivity with increasing temperature far below the glass transition temperature of PIMs is explained in terms of the loosely packed microporous structure and the formation of local intermolecular agglomerates due to interaction of π-electrons in aromatic moieties of the polymer backbone.
High performance polymers of intrinsic microporosity (PIMs) have emerged as novel materials with broad applications from gas separation to electronic devices. Sufficiently rigid, even contorted polymer chains show only limited molecular mobility, therefore undergo inefficient packing and give rise to intrinsic microporosity with pore size generally smaller than 1 nm and BET surface areas larger than 700 m2/g. Further performance optimization and long-term stability of devices incorporating PIMs rely on our understanding of structure-processing-property relationships and physical aging, in which glass transition plays a key role. Up to now no glass transition temperature (Tg) of PIMs could be detected with conventional thermal analysis techniques before degradation. Decoupling the time scales responsible for the glass transition and the thermal decomposition is a reliable strategy to overcome this. This was achieved by employing fast scanning calorimetry (FSC) based on a chip sensor, which is capable to heat and cool a small sample (ng-range) with ultrafast rates of several ten thousand K/s. FSC provides definitive evidence of glass transition of a series of PIMs with a special consideration on the chain rigidity. The determined glass transition temperature of these PIMs follows the order of the rigidity of their backbone structures. FSC provides the first clear-cut experimental evidence of the glass transition of PIM-EA-TB with a Tg of 663 K, PIM-1 of 644 K and PIM-DMDPH-TB of 630 K at a heating rate of 1Χ104 K/s. Local fluctuations are featured in glass transition of highly rigid PIMs. As conformational changes are prevented by the backbone rigidity, the glass transition must rather be assigned to local small scale fluctuations.
The phase behavior and molecular ordering of hexakishexyloxy triphenylene (HAT6) DLC under cylindrical nanoconfinement is studied utilizing differential scanning calorimetry (DSC) and dielectric spectroscopy (DS), where cylindrical nanoconfinement is established through embedding HAT6 into the nanopores of anodic aluminum oxide membranes (AAO), and a silica membrane with pore diameters ranging from 161 nm down to 12 nm. Both unmodified and modified pore walls were considered, and in the latter case the pore walls of AAO membranes were chemical treated with n octadecylphosphonic acid (ODPA) resulting in the formation of a 2.2 nm thick layer of grafted alkyl chains. Phase transition enthalpies decrease with decreasing pore size, indicating that a large proportion of the HAT6 molecules within the pores has a disordered structure, which increases with decreasing pore size for both pore walls. In the case of the ODPA modification the amount of ordered HAT6 is increased compared to the unmodified case. The pore size dependencies of the phase transition temperatures were approximated using the Gibbs Thomson equation, where the estimated surface tension is dependent on the molecular ordering of HAT6 molecules within the pores and upon their surface. DS was employed to investigate the molecular ordering of HAT6 within the nanopores. These investigations revealed that with a pore size of around 38 nm, for the samples with the unmodified pore walls, the molecular ordering changes from planar axial to homeotropic radial. However, the planar axial configuration, which is suitable for electronic applications, can be successfully preserved through ODPA modification for most of the pore sizes.
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.