Ingenieurwissenschaften und zugeordnete Tätigkeiten
Filtern
Erscheinungsjahr
- 2018 (211) (entfernen)
Dokumenttyp
- Zeitschriftenartikel (195)
- Beitrag zu einem Tagungsband (14)
- Buchkapitel (2)
Referierte Publikation
- ja (211) (entfernen)
Schlagworte
- SAXS (11)
- Residual stress (10)
- Additive manufacturing (9)
- Mechanochemistry (7)
- Microstructure (7)
- Small-angle X-ray scattering (7)
- Creep (6)
- Friction (6)
- MALDI-TOF MS (6)
- Welding (6)
- Cyclization (5)
- High-strength steels (5)
- In situ (5)
- Nanoparticle (5)
- Upconversion (5)
- Wear (5)
- Corrosion (4)
- Laser beam welding (4)
- Laser metal deposition (4)
- Niobium carbide (4)
- Polymer (4)
- Silver nanoparticles (4)
- XRD (4)
- 3D-Printing (3)
- Additive Manufacturing (3)
- Computed tomography (3)
- Femtosecond laser (3)
- Fracture mechanics (3)
- Hydrogen (3)
- Laser welding (3)
- Neutron diffraction (3)
- Polyester (3)
- Polylactide (3)
- Process parameters (3)
- Residual stresses (3)
- TEM (3)
- Weldments (3)
- X-ray diffraction (3)
- Active thermography (2)
- Alkali-Kieselsäure-Reaktion (2)
- All-optical switching (2)
- Alloy 31 (2)
- Alloys (2)
- Aluminium alloys (2)
- Aluminum alloys (2)
- Asymmetric coupler (2)
- Austenitic stainless steel (2)
- BAMline (2)
- Bacteria (2)
- Betonfahrbahndecke (2)
- Carbon fiber reinforced polymers (2)
- Catalysts (2)
- Ceramic (2)
- Cermet (2)
- Composite (2)
- Composite materials (2)
- Coupled generalized nonlinear Schrödinger equation (2)
- Crack closure (2)
- Creep-resistant steel (2)
- Damage (2)
- Deformation (2)
- Diffusion (2)
- Digital image correlation (2)
- Dimensional accuracy (2)
- Discotic liquid crystals (2)
- Dual-core photonic crystal fiber (2)
- Electron microscopy (2)
- Fatigue crack growth (2)
- Fatigue crack propagation (2)
- Fatigue crack propagation threshold (2)
- Fatigue strength (2)
- GMA welding (2)
- Hardness (2)
- Heat treatment (2)
- High temperature corrosion (2)
- Humidity (2)
- Hysteresis (2)
- IN718 (2)
- In situ studies (2)
- LIBS (2)
- Large-scale test (2)
- MOF (2)
- Mechanical properties (2)
- Nanopatricle (2)
- NbC (2)
- Non-destructive testing (2)
- Oxidation (2)
- Photooxidation (2)
- Plastic deformation (2)
- Polyethylene (2)
- Polymers (2)
- Quenching (2)
- Rare earth nanoparticles (2)
- Restraint (2)
- Ring-opening Polymerization (2)
- Ring-opening polymerization (2)
- Rubber (2)
- Selective laser melting (2)
- Serial sectioning (2)
- Short cracks (2)
- Small-angle x-ray scattering (2)
- Soft glass (2)
- Solid lubricants (2)
- Solidification cracking (2)
- Stainless steels (2)
- Steel (2)
- TPU (2)
- Thermal expansion (2)
- Thermography (2)
- Titanium (2)
- Transesterification (2)
- UV radiation (2)
- Ultrafast soliton fission (2)
- Ultrasound (2)
- Welding simulation (2)
- ZfP (2)
- 3D printer (1)
- 3D printing (1)
- 3D-finite element modeling (1)
- 9%Ni steel (1)
- ADXRD (1)
- AISI 304L (1)
- AM (1)
- ASR modelling (1)
- Ab initio calculation (1)
- Absorption spectrometry (1)
- Abwasser (1)
- Accelerated concrete prism test (1)
- Accelerated temporal integration (1)
- Accelerator magnet coils (1)
- Accelerator magnets (1)
- Active fibers (1)
- Adaptive control (1)
- Adaptive welding beam oscillation (1)
- Additive manufacturing (AM) (1)
- Adhesion (1)
- Ageing (1)
- Aging (1)
- Al-Cu-Li-alloy (1)
- Alkali-activated slag (1)
- Alkali–silica reaction (1)
- Aluminium oxide (1)
- Aluminum Alloys (1)
- Anisotropic fiber orientation (1)
- Annealing treatment (1)
- Antikensammlung Berlin (1)
- Artificial digestion (1)
- Artificial weathering (1)
- Atomic Scale (1)
- Austenitic (1)
- Automated expansion measurement (1)
- Automated manufacturing (1)
- Automatisierte Fertigung (1)
- Automotive application (1)
- BET (1)
- Baltic Sea (1)
- Behavior (1)
- Beschichtung (1)
- Beta-eucryptite (1)
- Biaxial strength (1)
- Binder jetting (1)
- Bio Ceramic (1)
- Biofouling (1)
- Biogeochemistry (1)
- Biomaterials (1)
- Biomedical application (1)
- Bisphenol A (1)
- Bitter technique (1)
- Blends (1)
- Bone grafting (1)
- Bone regeneration (1)
- Bone substitutes (1)
- Borosilicate glass (1)
- Boson peak (1)
- Brillouin (1)
- Broadband dielectric spectroscopy (1)
- Brunauer-Emmett-Teller (1)
- Build-up strategy (1)
- C-C coupling (1)
- CCT diagrams (1)
- CCUS, supercritical/dense phase CO2, carbon steels, martensitic steel, superaustenite steel, droplet corrosion (1)
- CEC-L-103 (1)
- CFD model (1)
- CFRP (1)
- COSMO (1)
- CT (1)
- Calcination (1)
- Calcium Cobaltite (1)
- Calcium monofluoride (1)
- Carbon (1)
- Carbon footprint (1)
- Carbon steel (1)
- Cement (1)
- Changes with time (1)
- Chemical composition (1)
- Clad steels (1)
- Climate (1)
- Coarse grained heat affected zone (1)
- Coastal protection (1)
- Coating (1)
- Cobald based alloy (1)
- Cohesive finite elements (1)
- Cold-welding (1)
- Complex Molecular Systems (1)
- Computed Tomography (1)
- Computed tompgraphy (1)
- Concrete (1)
- Condition monitoring (1)
- Conductor-like screening model (1)
- Constraint (1)
- Cooling rate (1)
- Coordinate measurement machine (1)
- Copper hydroxide (1)
- Cordierite (1)
- Core shell structure (1)
- Core-shell nanoparticles (1)
- Corrosion resistance (1)
- Corrosion testing (1)
- Coupling (1)
- CrN/NbN (1)
- Crack closure mechanisms (1)
- Creep mechanisms (1)
- Creep resistant steel (1)
- Critical strain (1)
- Crosslinking (1)
- Cryogenic temperature (1)
- Crystallographic texture (1)
- Cupriavidus metallidurans (1)
- Cyclic J-integral (1)
- Cyclic R-curve (1)
- Cyclic R-curve analysis (1)
- Cyclic stress-strain curve (1)
- Cyclisation (1)
- DED (1)
- DIC (1)
- DNA origami (1)
- Damage evolution (1)
- Defects (1)
- Deformed geometry (1)
- Degradation (1)
- Density measurement (1)
- Deposition rate (1)
- Design of experiments (1)
- Destabilization (1)
- Diaspore (1)
- Die-cast aluminum (1)
- Dielectric ceramic (1)
- Dielectric heating (1)
- Digitalisierung (1)
- Digitization (1)
- Dilatometry (1)
- Disorder (1)
- Dissimilar metal weld overlays (1)
- Dissimilar welds (1)
- Duplex (1)
- Dynamic recrystallization (1)
- Dynamic vapor sorption (1)
- EBSD (1)
- EPR (1)
- ESI-TOF-MS (1)
- ESR (1)
- Early stages (1)
- Eddy current (1)
- Editorial (1)
- Education (1)
- Effective properties (1)
- Einzelzellanalyse (1)
- Elastic follow-up (1)
- Elastic-plastic fracture mechanics (1)
- Electric conductivity (1)
- Electrical connectors (1)
- Electrical resistance (1)
- Electro-plated nickel coatings (1)
- Electrochemical potentiokinetic reactivation (1)
- Electroless Ni-P (1)
- Electromagnetic influence (1)
- Electromagnetic weld pool support (1)
- Electron back-scattered diffraction (1)
- Embrittlement (1)
- Emission (1)
- Endurance limit (1)
- Engine combustion (1)
- Engine performance (1)
- Environment (1)
- Environmental stress cracking (ESC) (1)
- Epitaxial thin films (1)
- Equivalent heat source (1)
- Equivalent stress concentration factors (1)
- Excess surface work (1)
- Expanding cavity model (1)
- FIB Tomography (1)
- FRET (1)
- FTIR (1)
- Fast Scanning Calorimetry (1)
- Fast measurement (1)
- Fe2TiO5 (1)
- Femtosecond laser ablation (1)
- Ferritic steels (1)
- Ferromagnetic steels (1)
- Feuchtemessung (1)
- Fiber laser (1)
- Fiber-reinforced composite (1)
- Fiber-reinforced concrete (1)
- Finite element method (FEM) (1)
- Finland (1)
- Fire (1)
- Flue gas desulphurisation facilities (1)
- Fluorescence (1)
- Fluorescence lifetime (1)
- Fluorophore (1)
- Formaldehyde (1)
- Fourier series (1)
- Fractal Microstructure (1)
- Fracture (1)
- Fracture resistance (1)
- Free weathering (1)
- Fresnel reflection (1)
- Friction stir processing (1)
- Full notch creep test (FNCT) (1)
- Full penetration (1)
- Fungi (1)
- Fusion zone size (1)
- Fusion zone, nickel alloys (1)
- GC-FID (1)
- GFRP (1)
- GMAwelding (1)
- GMR (1)
- GMR sensors (1)
- GTAW (1)
- Gamma irradiation (1)
- Gap bridging (1)
- Gas solubility (1)
- Geosynthetics (1)
- Geotextiles (1)
- Glass (1)
- Glass crystallization stress (1)
- Glass transition (1)
- Glass-ceramics definition (1)
- Glasses (1)
- Gleeble testing (1)
- Gold (1)
- Grade S960QL steel (1)
- Gradient-enhanced fatigue model (1)
- Grain Boundary Corrosion (1)
- Grain size (1)
- Graphene (1)
- Graphite furnace (1)
- Greek curse tablets (1)
- Green-Death solution (1)
- Growth defects (1)
- HR-CS-MAS (1)
- HSLA (1)
- HSLA steel (1)
- Hard metals (1)
- Hardmetal (1)
- Heat affected zone (1)
- Heat diffusion (1)
- Heat flow (1)
- Heat-affected zone (1)
- Heizöllagerbehälter (1)
- Henry's law constant (1)
- Hessian analysis (1)
- High brightness (1)
- High interstitial austenitic steel (1)
- High power (1)
- High strength steel (1)
- High-power laser beam (1)
- High-strength steel sheets (1)
- Hipims (1)
- Hohlprofilknoten (1)
- Hot steam (1)
- Hybrid laser-arc welding (1)
- Hydrocarbons (1)
- Hydrogen assisted cracking (1)
- Hydrophilicity (1)
- ICP-MS (1)
- IR (1)
- Image processing (1)
- Impact (1)
- Impact absorbed energy (1)
- Impact factor (1)
- Impact wear (1)
- In situ diffraction (1)
- In situ strain (1)
- In-situ SEM micro shear deformation (1)
- In-situ characterization of GDLs (1)
- In-situ synchrotron X-ray computed tomography (1)
- In-situ synchrotron X-ray radiography (1)
- Inclusions (1)
- Indentation (1)
- Inorganic polymers (1)
- Interdiffusion (1)
- Interfacial strength (1)
- Internal Sulfidation (1)
- Internal friction (1)
- Internal stress (1)
- Inverse analysis (1)
- Ionic liquid (1)
- Ionic liquid crystalls (1)
- Iron oxide films (1)
- Iron speciation (1)
- Iron–chromium–nickel alloy (1)
- Isostatic hot pressing (HIP) (1)
- Isotope dilution mass spectrometry (1)
- Katalysator (1)
- Kerbspannungskonzept (1)
- Kitagawa-Takahashi diagram (1)
- Knoevenagel condensation (1)
- LTT Weld Filler Materials (1)
- Laboratory X-ray diffraction (1)
- Laminography (1)
- Lanthanide-doped nayf-4 (1)
- Laser keyhole welding (1)
- Laser scanning microscopy (LSM) (1)
- Laser surfacing (1)
- Laser-induced X-ray emission (1)
- Laser-induced periodic surface structures (1)
- Layer-by-Layer (1)
- Lead isotopes (1)
- Life prediction (1)
- Life sciences (1)
- Light curing (1)
- Liquid metal embrittlement (1)
- Liquid phase sintering (1)
- Low carbon steel (1)
- Low heat input Gma welding (1)
- Low transformation temperature filler materials (1)
- MAG welding (1)
- MRFA (1)
- Machining (1)
- Magnesium (1)
- Magnetic domain distribution (1)
- Magnetic stray field (1)
- Magnetic stray fields (1)
- Magnetomechanical effect (1)
- Magnetpartikel (1)
- Marble deterioration (1)
- Marble sculptures (1)
- Marine atmosphere (1)
- Mars (1)
- Martensitic stainless steel (1)
- Martensitic transformation (1)
- Material modeling (1)
- Material science (1)
- Measurement (1)
- Measuremment uncertainty (1)
- Mechanical analysis (1)
- Melt pool dynamics (1)
- Mesoporosity (1)
- Metal Magnetic Memory (1)
- Metal magnetic memory (1)
- Metal matrix composite (1)
- Metal matrix composites (1)
- Metal-organic frameworks (1)
- Methane (1)
- Mg1-xZnxTiO3 (1)
- Micro analysis (1)
- Microalloyed steels (1)
- Microcracked ceramics (1)
- Micromechanical modeling (1)
- Microstructur (1)
- Microstructure Tensile strength (1)
- Microstructure and texture (1)
- Microstructure evolution (1)
- Microwave synthesis (1)
- Microwaves (1)
- Milling (1)
- Mobility (1)
- Modal analysis (1)
- Modeling (1)
- Molecular Organic Frameworks (1)
- Molybdenum disulphide (1)
- Monotonic and cyclic crack driving force (1)
- Multi-pass welding (1)
- Multiaxial deformation (1)
- Multifunctional efficiency (1)
- Multilaysers (1)
- Multiple crack initiation (1)
- Multiple cracking (1)
- NGS (1)
- NIR (1)
- Nano-scratch test (1)
- Nanocomposite (1)
- Nanocrystals (1)
- Nanomaterial (1)
- Nanomedicine (1)
- Nanoparticles (1)
- Nanophotonics (1)
- Nanopores (1)
- Nanoscale multilayers (1)
- Nanostructuring (1)
- Narrow gap welding (1)
- Nasschemie (1)
- Natural silver wires (1)
- Near infrared (1)
- Near-infrared light (1)
- Neural networks (1)
- Neutron scattering (1)
- NiTi (1)
- Nickel (1)
- Nickel foam (1)
- Niobium carbide (NbC) (1)
- Nitric acid (1)
- Non lienear processes (1)
- Nondestructive testing (1)
- Nonferrous slag (1)
- Nonlinearity (1)
- Notch (1)
- Notch stress approach (1)
- Nuclear Magnetic Resonance (1)
- Nuclear power plants (1)
- Number density (1)
- Numerical simulation (1)
- Numerical welding simulation (1)
- Optical centrifugation (1)
- Optical measurement (1)
- Order parameter (1)
- Organic/inorganic block copolymer (1)
- Orientation (1)
- Orientation distribution (1)
- Outdoor weathering (1)
- Oxide (1)
- PAEKs (1)
- PUR (1)
- PVD hard coating (1)
- Partial penetration (1)
- Passive film (1)
- Passive thermography (1)
- Passivity (1)
- Pb isotopes (1)
- Peroxy-fuels (1)
- Pest control (1)
- Phase transformation (1)
- Phase-contrast microscopy (1)
- Photocatalysis (1)
- Photocatalytic activity (1)
- Photonic devices (1)
- Photophysics (1)
- Photosensitizer (1)
- Physical aging (1)
- Physical vapor deposition (PVD) (1)
- Physical vapour deposition (PVD) (1)
- Pinholes (1)
- Pitting corrosion (1)
- Plume heating (1)
- Polyacrylamide (1)
- Polycondensation (1)
- Polycrystals (1)
- Polyelektrolyt (1)
- Polyethylen (1)
- Polylactides (1)
- Polymer of intrinsic microporosity (1)
- Polymer optical fibre (1)
- Polymer particles (1)
- Polymeric Materials (1)
- Polymerization (1)
- Polymers with intrinsic microporosity (1)
- Polymorphism (1)
- Polymorphs (1)
- Polyurethane (1)
- Porcelain (1)
- Porosity (1)
- Porosity reduction (1)
- Post Weld Heat Treatment (PWHT) (1)
- Preceramic polymer (1)
- Precipitation (1)
- Pressure tanks (1)
- Pressure vessel (1)
- Process simulation (1)
- Pseudobrookite (1)
- Quantum Yield (1)
- Quantum dot (1)
- Quantum yield (1)
- R-curve analysis (1)
- RAMAN (1)
- Radar (1)
- Radiation protection (1)
- Radio waves (1)
- Raman spectroscopy (1)
- Ratiometric sensing (1)
- Reaction-sintering (1)
- Reciprocating sliding (1)
- Reconstructed ion chromatograms (1)
- Reference (1)
- Reference measurements (1)
- Reference organisms (1)
- Relaxation (1)
- Residual Stresses (1)
- Resistance (1)
- Resistance spot welding (1)
- Robust nano objects (1)
- Rod-like liquid crystals (1)
- S-Phase (1)
- SEM (1)
- SLM (1)
- SSTC Model (1)
- Sample holder (1)
- Scanning acoustic microscopy (SAM) (1)
- Scattering (1)
- Schmelze-Masse-Fließrate (1)
- Schweißnahtgeometrie (1)
- Schädigungsgrad (1)
- Seal performance (1)
- Secondary heat source (1)
- Secondary stresses (1)
- Segregation (1)
- Selective Laser Melting (1)
- Self-Assembly (1)
- Self-assembly (1)
- Semiconductive layer (1)
- Sensing (1)
- Sensor (1)
- Shape memory alloys (1)
- Shear testing (1)
- Short crack propagation (1)
- Silbernanopartikel (1)
- Simvastatine (1)
- Single photon and quantum effects (1)
- Single-crystal (1)
- Singulettsauerstoff (1)
- Sintering (1)
- Slow crack growth (SCG) (1)
- Slurry optimization (1)
- Smart industry (4.0) (1)
- Soft-templated (1)
- Solid-State-Synthesis (1)
- Solvation properties (1)
- Spark plasma sintering (1)
- Spatial analyses (1)
- Specific heat spectroscopy (1)
- Spectroscopy (1)
- Spirocyclic (1)
- Spray drying (1)
- Stainless steel (1)
- Standards (1)
- Steam oxidation resistance (1)
- Stoichiometric phases (1)
- Strain difference (1)
- Strain hardening (1)
- Strain rate (1)
- Strain rates (1)
- Strain-rate (1)
- Strength mismatch (1)
- Stress Coupling (1)
- Stress Relief Cracking (SRC) (1)
- Stress-strain behavior (1)
- Stress-strain relations (1)
- Stress-strain-behavior (1)
- Structural steel (1)
- Sulfidation (1)
- Sulphidation (1)
- Superalloy (1)
- Superalloy single crystals (1)
- Supercapacitor (1)
- Superconducting (1)
- Superconducting magnet (1)
- Superconducting magnets (1)
- Support configurations (1)
- Supramolecules (1)
- Surface cracks (1)
- Surface defects (1)
- Surface nucleation (1)
- Sustainability (1)
- Synchrotron (1)
- Synchrotron X-ray diffraction (1)
- Synchrotron X-ray refraction (1)
- Synchrotron X-ray refraction radiography (1)
- Synchrotron diffraction (1)
- Synthesis (1)
- T1 precipitate (1)
- THz Spectroscopy (1)
- TIG (1)
- TIG-welding (1)
- Tausalz (1)
- Temperature (1)
- Temperature distribution (1)
- Tensile load (1)
- Theranostics (1)
- Thermal conductivity (1)
- Thermal desorption analysis (1)
- Thermal-desorption spectroscopy (1)
- Thermoelectric (1)
- Thermoelectrics (1)
- Thermoresponsive polymer (1)
- Thick-walled steel (1)
- Thickening (1)
- Ti-6Al-4V (1)
- Ti-based colloids (1)
- TiMgN (1)
- Titanium alloy (1)
- Titanium nitride (1)
- ToF-SIMS (1)
- Tool (1)
- Topography (1)
- Toughness (1)
- Traceability (1)
- Transformable steels (1)
- Transient heat transfer (1)
- Transmission electron microscopy (1)
- Tribooxidation (1)
- Tricalcium Phosphate (1)
- Tubular joints (1)
- Turbine components (1)
- Turning (1)
- Twinning (1)
- UCST-type polymer (1)
- UHPC (1)
- UPLC (1)
- Ultra high molecular weight (1)
- Ultrafine particles (1)
- Ultrahigh-performance concrete (UHPC) (1)
- Ultrashort laser material interaction (1)
- Ultrasonic testing (1)
- Ultrasonic velocities (1)
- Ultrasonics (1)
- Upconverting nanoparticles (1)
- VOC (1)
- VOx catalyst (1)
- Vacuum (1)
- Vapor recondensation (1)
- Viscoplasticity (1)
- Volume fraction (1)
- WAXS (1)
- Water (1)
- Water droplet erosion resistance (1)
- Water/alcohol mixtures (1)
- Wear mechanisms (1)
- Weld geometry (1)
- Weld pool (1)
- Weld seam geometry (1)
- Welded joints (1)
- Welding residual stresses (1)
- Wood (1)
- Wood protection (1)
- X-ray absorption near-edge structure (1)
- X-ray absorption spectroscopy (1)
- X-ray absorption tomography (1)
- X-ray computed tomography (1)
- X-ray computed tomography (CT) (1)
- X-ray diffraction (XRD) (1)
- X-ray laminography (1)
- X-ray photoelectron spectroscopy (1)
- X-ray radiography (1)
- X-ray refraction (1)
- XAFS (1)
- Xerogel (1)
- Yield strength (1)
- Young`s modulus (1)
- Young’s modulus (1)
- ZIF (1)
- Zeolithe (1)
- Zinc (1)
- Zirconium (1)
- contour method (1)
- dipolar polarization (1)
- gold (1)
- magnesium (1)
- nanoparticle (1)
- neutron diffraction (1)
- permittivity (1)
- residual stress analysis (1)
- space charge polarization (1)
- subgrain structure (1)
- Ägyptisches Museum Berlin (1)
- Äquivalente Spannungskonzentrationsfaktoren (1)
Organisationseinheit der BAM
- 9 Komponentensicherheit (63)
- 6 Materialchemie (50)
- 5 Werkstofftechnik (42)
- 8 Zerstörungsfreie Prüfung (39)
- 7 Bauwerkssicherheit (26)
- 9.4 Integrität von Schweißverbindungen (25)
- 6.3 Strukturanalytik (24)
- 1 Analytische Chemie; Referenzmaterialien (21)
- 8.5 Röntgenbildgebung (21)
- 9.3 Schweißtechnische Fertigungsverfahren (21)
The mechanism of action of zirconium permanent modifiers on graphite surfaces was investigated in order to understand its influence on the analytical signal in atomic and molecular absorption spectrometry (AAS/MAS). For this, the molecule formation of CaF was studied, which is used for the indirect analytical determination of fluorine in high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). The kinetics of this reaction was established by monitoring its molecular spectrum at different atomisation temperatures. An Arrhenius plot showed a pseudo-first order reaction with respect to fluorine (n = 1). An intermediate state was isolated, and its structure was elucidated by spectroscopic methods: scanning electron microscopy with energy dispersive X-ray spectroscopy (SEMEDX), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XANES and EXAFS), and Raman microspectroscopy. We propose here a mechanism, where ZrO2 acts as a heterogeneous catalyst: after a pyrolytic step, an intermediate state of ZrO(OCaF) is activated, and at higher temperatures, CaF(g) is released from the zirconium-coated graphite surface. No evidence of the formation of zirconium carbide was found. Consequently, as the CaF formation is catalysed by a heterogeneous catalyst, surface modifications with ZrO2 nanoparticles and ZrO xerogels were investigated in order to increase the surface area. Their influence was evaluated in the molecule formation of CaF, CaCl, CaBr, and CaI. Graphite furnace modification with zirconium oxide nanoparticles proves to be the best choice for fluorine analysis with a signal enhancement of more than eleven times with respect a non-coated graphite furnace. However, the influence of zirconium modifications in the analytical signals of Cl, and I is lower than the F signals or even negative in case of the Br. Understanding zirconium modifiers as heterogeneous catalysts offers a new perspective to AAS and MAS, and reveals the potential of surface analytical methods for development of improved permanent modifiers and graphite furnace coatings.
Two divalent manganese aminophosphonates, manganese mono (nitrilotrimethylphosphonate) (MnNP3) and manganese bis N-(carboxymethyl)iminodi(methylphosphonate)) (Mn(NP2AH)2), have been prepared by mechanochemical synthesis and characterized by powder X-ray diffraction (PXRD). The structure of the novel compound Mn(NP2AH)2 was determined from PXRD data. MnNP3 as well as Mn(NP2AH)2 exhibits a chain-like structure.
In both cases, the manganese atom is coordinated by six oxygen atoms in a distorted octahedron. The local coordination around Mn was further characterized by extended X-ray absorption fine structure. The synthesis process was followed in situ by synchrotron X-ray diffraction revealing a three-step reaction mechanism. The asprepared manganese(II) phosphonates were calcined on air.
All samples were successfully tested for their suitability as catalyst material in the oxygen evolution reaction.
A series of Ca-based coordination polymers were prepared mechanochemically by milling Ca(OH)2 with phthalic acid (H2oBDC), isophthalic acid (H2mBDC), and terephthalic acid (H2pBDC). The hydrated compounds [Ca(oBDC)(H2O)], [Ca(mBDC)(H2O)3.4], and [Ca(pBDC)(H2O)3] were prepared for the first time via mechanochemical routes. The refined structures were validated by extended X-ray absorption data. The new dehydrated compound [Ca(oBDC)] (1-H2O), obtained after the thermal post-treatment of 1 in a reversible phase transition process, was determined ab initio based on the powder X-ray diffraction (PXRD) data. The materials were thoroughly characterized using elemental analysis, thermal analysis, and spectroscopic methods: magic-angle spinning NMR and attenuated total reflection-infrared spectroscopy. The specific surface areas and sorption properties of the hydrated and dehydrated samples were determined using the isotherms of gas sorption and dynamic vapor sorption measurements.
A three-dimensional multi-physics numerical model was developed for the calculation of an appropriate equivalent volumetric heat source and the prediction of the transient thermal cycle during and after fusion welding. Thus the modelling process was separated into two studies. First, the stationary process simulation of full-penetration keyhole laser beam welding of a 15 mm low-alloyed steel thick plate in flat position at a welding speed of 2 m/min and a laser power of 18 kW was performed. A fixed keyhole with a right circular cone shape was used to consider the energy absorbed by the workpiece and to calibrate the model. In the calculation of the weld pool geometry and the local temperature field, the effects of phase transition, thermo-capillary convection, natural convection and temperature-dependent material properties up to evaporation temperature were taken into account. The obtained local temperature field was then used in a subsequent study as an equivalent heat source for the computation of the transient thermal field during the laser welding process and the cooling stage of the part. The system of partial differential equations, describing the stationary heat transfer and the fluid dynamics, were strongly coupled and solved with the commercial finite element software COMSOL Multiphysics 5.0. The energy input in the transient heat transfer simulation was realised by prescription of the nodes temperature. The prescribed nodes reproduced the calculated local temperature field defining the equivalent volumetric heat source. Their translational motion through the part was modelled by a moving mesh approach. An additional remeshing condition and helper lines were used to avoid highly distorted elements. The positions of the elements of the polygonal mesh were calculated with the Laplace’s smoothing approach. Good correlation between the numerically calculated and the experimentally observed weld bead shapes and transient temperature distributions was found.
Combining experiments and all-atom molecular dynamics simulations, we study the conformational behavior of polyacrylamide (PAM) in aqueous alcohol mixtures over a wide range of temperatures. This study Shows that even when the microscopic interaction is dictated by hydrogen bonding, unlike its counterparts that present a lower critical solution temperature (LCST), PAM shows a counterintuitive tunable upper critical solution temperature (UCST)-type phase transition in water/alcohol mixtures that was not reported before. The Phase transition temperature was found to be tunable between 4 and 60 1C by the type and concentration of alcohol in the mixture as well as by the solution concentration and molecular weight of the polymer. In addition, molecular dynamics simulations confirmed a UCST-like behaviour of the PAM in aqueous alcoholic solutions.
Additionally, it was observed that the PAM is more swollen in pure alcohol solutions than in 80% alcoholic solutions due to y-like behaviour. Additionally, in the globular state, the size of the aggregates was found to increase with increasing solvent hydrophobicity and polymer concentration of the solutions. Above ist Phase transition temperature, PAM might be present as individual polymer chains in the coil state (r10 nm). As PAM is a widespread polymer in many biomedical applications (gel electrophoresis, etc.), this finding could be of high relevance for many more practical applications in high performance pharmaceuticals and/or sensors.
Electrochemical tests, hardness measurements, and microstructure analysis are performed to study the influence of austenitizing, quenching, and tempering parameters on the corrosion resistance of the martensitic stainless steel grade X50CrMoV15 (1.4116). Different heat treatment states were studied using an adapted EPR-Test to evaluate the chromium distribution and depletion caused by the formation and dissolution of chromium rich carbides. The EPR results were correlated with pitting corrosion behavior, demonstrating the strong effect of heat treatment parameters on the susceptibility of martensitic stainless steels to corrosion phenomena.
One of the main factors affecting the use of lasers in the industry for welding thick structures is the process accompanying solidification cracks. These cracks mostly occurring along the welding direction in the welding center, and strongly affect the safety of the welded components. In the present study, to obtain a better understanding of the relation between the weld pool geometry, the stress distribution and the solidification cracking, a three-dimensional computational fluid dynamic (CFD) model was combined with a thermo-mechanical model. The CFD model was employed to analyze the flow of the molten metal in the weld pool during the laser beam welding process. The weld pool geometry estimated from the CFD model was used as a heat source in the thermal model to calculate the temperature field and the stress development and distributions. The CFD results showed a bulging region in the middle depth of the weld and two narrowing areas separating the bulging region from the top and bottom surface. The thermo-mechanical simulations showed a concentration of tension stresses, transversally and vertically, directly after the solidification during cooling in the region of the solidification cracking.
In recent years, laser beam welding has found wide applications in many industrial fields. Solidification cracks are one of the most frequently encountered welding defects that hinder obtaining a safe weld joint. Decades of research have shown that one of the main causes of such cracks are the strain and the strain rate. Obtaining meaningful measurements of these strains has always been a major challenge for scientists, because of the specific environment of the measurement range and the many obstacles, as well as the high temperature and the plasma plume. In this study, a special experimental setup with a high-speed camera was employed to measure the strain during the welding process. The hot cracking susceptibility was investigated for 1.4301 stainless steel, and the critical strain required for solidification crack formation was locally and globally determined.
Hard and wear resistant coatings deposited by PVD techniques have been characterized for decades for their capabilities to protect steel substrates from corrosion. In the present work the effect of Mg incorporated into TiN coatings is described in terms of the corrosion behavior as well as the mechanical and structural properties.
TiN and TiMgN films with Mg contents between 10 and 35 at.% were deposited onto mirror polished 100Cr6 (1.3505) steel samples with 2.5 and 5 μm thickness by using DC magnetron sputtering. The corrosion protection capabilities of the coatings were characterized by neutral salt spray (NSS) test, considering the amounts and sizes of growth defects inherent in each coated sample as determined by a recently developed optical scan method (Large Area High Resolution mapping). The defect data were statistically analyzed for improved interpretation of NSS test results. Chosen growth defects were additionally analyzed by focused ion beam technique. Furthermore the coating composition and morphology, the hardness and the tribological behavior were characterized.
Polished steel samples coated with 2.5 μm TiMgN containing about 35 at.% Mg were in the plane free of corrosion after 24 h in a NSS test. TiMgN with 10 or 20 at.% Mg only provided a slightly improved corrosion protection in relation to pure TiN coatings, which was limited to certain types of growth defects. The highest Mg containing coatings exhibited a decreased hardness down to 1200 or 1800 HV depending on type of deposition (HV 1200: Ti- and Mg-target with rotating substrate holder, 1800: Mg-plugged Ti-target with static substrate holder), but also showed a strongly improved wear resistance against Al2O3 related to pure TiN. By analyzing the NSS test results it was found that the corrosion behavior of the coated samples did not only depend strongly on the Mg content, but also on the sample individual defect concentrations. Therefore this subject is extensively discussed.
THz and mid IR spectroscopy of high-molecular PE (HMW) and ultra high-molecular PE (UHMW) reveals modifications of the molecular structure. Characteristic absorption bands are changed if the two materials are exposed by γ-Co60 radiation up to 600 kGy and subsequently stored at an annealing temperature of 398 K until for 729 days.