Characterization of temperature-dependent optical material properties of polymer powders

2015 ◽  
Author(s):  
Tobias Laumer ◽  
Thomas Stichel ◽  
Thomas Bock ◽  
Philipp Amend ◽  
Michael Schmidt
Keyword(s):  
Material Properties ◽  
Optical Material ◽  
Temperature Dependent ◽  
Polymer Powders

scholarly journals Determination of the Temperature-Dependent Thermal Material Properties in the Cooling Process of Steel Plates

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Dimitri Rothermel ◽  
Thomas Schuster ◽  
Roland Schorr ◽  
Martin Peglow
Keyword(s):  
Heat Conduction ◽  
Material Properties ◽  
Nonlinear Partial Differential Equation ◽  
Steel Plates ◽  
Temperature Evolution ◽  
Cooling Process ◽  
Temperature Dependent ◽  
Material Parameters ◽  
Thermophysical Characterization

Accelerated cooling (ACC) is a key technology in producing thermomechanically controlled processed (TMCP) steel plates. In a TMCP process, hot plates are subjected to a strong cooling resulting in a complex microstructure leading to increased strength and fracture toughness. The microstructure, residual stresses, and flatness deformations are strongly affected by the temperature evolution during the cooling process. Therefore, the full control (quantification) of the temperature evolution is essential regarding plate design and processing. It can only be achieved by a thermophysical characterization of the material and the cooling system. In this paper, the focus is on the thermophysical characterization of the material properties which govern the heat conduction behavior inside of the plates. Mathematically, this work considers a specific inverse heat conduction problem (IHCP) utilizing inner temperature measurements. The temperature evolution of a heated steel plate passing through the cooling device is modeled by a 1D nonlinear partial differential equation with temperature-dependent material parameters which describe the characteristics of the underlying material. Usually, the material parameters considered in IHCPs are often defined as functions of the space and/or time variables only. Since the measured data (the effect) and the unknown material properties (the cause) depend on temperature, the cause-to-effect relationship cannot be decoupled. Hence, the parameter-to-solution operator can only be defined implicitly. By proposing a parametrization approach via piecewise interpolation, this problem can be resolved. Lastly, using simulated measurement data, the presentation of the numerical procedure shows the ability to identify the material parameters (up to some canonical ambiguity) without any a priori information.

Temperature Field Evolution during Flash Butt Welding of Railway Rails

2016 ◽  
Vol 879 ◽  
pp. 2088-2093 ◽  
Author(s):  
Leonhard Weingrill ◽  
Jörg Krutzler ◽  
Norbert Enzinger
Keyword(s):  
Temperature Field ◽  
Material Properties ◽  
Rail Steel ◽  
Fe Model ◽  
Temperature Dependent ◽  
Detailed Characterization ◽  
Butt Welding ◽  
Welding Sequence ◽  
Transition Resistance

Flash butt welding (FBW) of railway rails was investigated in this work. For this purpose samples of R260 rail steel and 60E1 profile were instrumented and subsequently welded on a Schlatter GAA 100 welding machine under industrial conditions. The intention is to gain in depth process knowledge by more accurately depicting thermal cycles for an entire welding sequence in the immediate proximity of the weld as well as in the heat affected zone (HAZ). A detailed characterization of the single stages of the heat up phase of the process is important. Additionally, the secondary welding voltage was measured simultaneously during the experiments to characterize the transient heat input. Moreover, these data were used in the analysis of the temperature signals to better cope with electrical interferences. Additionally, a finite element (FE) model of this FBW process was developed in the present work. Its implementation and solution is realized with the help of ESI’s FE-software SYSWELD. A strong coupled thermo-electrokinetical and metallurgical calculation routine was used. The model comprises the transition resistance at the welding surfaces as the main heat source to the process. Temperature dependent material properties and a corresponding metallurgical model based on an experimental CCT diagram of the rail steel R350HT are implemented in the simulation as well.

scholarly journals The G-Protein α-Subunit GasC Plays a Major Role in Germination in the Dimorphic FungusPenicillium marneffei

Genetics ◽  
2003 ◽  
Vol 164 (2) ◽  
pp. 487-499 ◽  
Author(s):  
Sophie Zuber ◽  
Michael J Hynes ◽  
Alex Andrianopoulos
Keyword(s):  
G Protein ◽  
Germination Rate ◽  
Yeast Cells ◽  
Class Iii ◽  
Temperature Dependent ◽  
Gene Encoding ◽  
Α Subunit ◽  
G Protein Α Subunit ◽  
Opportunistic Human Pathogen

AbstractThe opportunistic human pathogen Penicillium marneffei exhibits a temperature-dependent dimorphic switch. At 25°, multinucleate, septate hyphae that can undergo differentiation to produce asexual spores (conidia) are produced. At 37° hyphae undergo arthroconidiation to produce uninucleate yeast cells that divide by fission. This work describes the cloning of the P. marneffei gasC gene encoding a G-protein α-subunit that shows high homology to members of the class III fungal Gα-subunits. Characterization of a ΔgasC mutant and strains carrying a dominant-activating gasCG45R or a dominant-interfering gasCG207R allele show that GasC is a crucial regulator of germination. A ΔgasC mutant is severely delayed in germination, whereas strains carrying a dominant-activating gasCG45R allele show a significantly accelerated germination rate. Additionally, GasC signaling positively affects the production of the red pigment by P. marneffei at 25° and negatively affects the onset of conidiation and the conidial yield, showing that GasC function overlaps with functions of the previously described Gα-subunit GasA. In contrast to the S. cerevisiae ortholog Gpa2, our data indicate that GasC is not involved in carbon or nitrogen source sensing and plays no major role in either hyphal or yeast growth or in the switch between these two forms.

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