The Effects of Moisture on the Material Properties and Behavior of Thermoplastic Polyimide Composites

Author(s):  
MR VanLandingham ◽  
RF Eduljee ◽  
JW Gillespie
Author(s):  
Carl E. Jaske

This paper reviews the metallurgy and behavior of centrifugally cast heat-resistant alloys for ammonia, methanol, and hydrogen reformer furnaces. The alloys include HK and HP, as well as proprietary versions of these materials produced by various foundries. Alloying and metallurgical factors that affect resistance to oxidation, carburization, and high temperature creep are discussed. Examples of the effects of environment and temperature on material behavior are provided. Finally, the use of material properties to predict the long-term performance of reformer furnace components is reviewed.


Author(s):  
S. Adapa ◽  
T. P. Chu ◽  
J. A. Schneider

An Image correlation technique to evaluate the structural properties and behavior of the Friction Stir Welds (FSW) is presented. The technique used is Sub-Pixel Digital Image Correlation (SPDIC). Four weld samples made of Al-2219 and Al-2195 alloys but different surface treatments are tested under tensile loads and the digital images of these samples are correlated using SPDIC. Stress-strain graphs and strain contours are obtained from the results. From the stress-strain graphs the structural properties and the behavior of the weld material are determined. The results indicate that SPDIC is a steadfast tool to determine the structural behavior and material properties of the weld samples.


2014 ◽  
Vol 587-589 ◽  
pp. 1100-1105
Author(s):  
Jian Yang ◽  
Jin Sheng Wang ◽  
Xin Peng

Reactive Powder Concrete is proposed to be used in the ballastless track for its excellent material properties due to existing problems of high speed railway ballastless track. Three different unit types of RPC frame slab track were proposed through optimization design and the mechanical behavior of these frame slab track was analyzed. The results show that the RPC slab track meet the requirements of bearing capacity, the suggested type of RPC slab track is a frame slab with increased thickness because of its higher techno-economic advantages.


2018 ◽  
Vol 41 ◽  
Author(s):  
Peter DeScioli

AbstractThe target article by Boyer & Petersen (B&P) contributes a vital message: that people have folk economic theories that shape their thoughts and behavior in the marketplace. This message is all the more important because, in the history of economic thought, Homo economicus was increasingly stripped of mental capacities. Intuitive theories can help restore the mind of Homo economicus.


2019 ◽  
Vol 42 ◽  
Author(s):  
Jeffrey R. Alberts ◽  
Christopher Harshaw ◽  
Gregory E. Demas ◽  
Cara L. Wellman ◽  
Ardythe L. Morrow

Abstract We identify the significance and typical requirements of developmental analyses of the microbiome-gut-brain (MGB) in parents, offspring, and parent-offspring relations, which have particular importance for neurobehavioral outcomes in mammalian species, including humans. We call for a focus on behavioral measures of social-emotional function. Methodological approaches to interpreting relations between the microbiota and behavior are discussed.


Author(s):  
N. David Theodore ◽  
Mamoru Tomozane ◽  
Ming Liaw

There is extensive interest in SiGe for use in heterojunction bipolar transistors. SiGe/Si superlattices are also of interest because of their potential for use in infrared detectors and field-effect transistors. The processing required for these materials is quite compatible with existing silicon technology. However, before SiGe can be used extensively for devices, there is a need to understand and then control the origin and behavior of defects in the materials. The present study was aimed at investigating the structural quality of, and the behavior of defects in, graded SiGe layers grown by chemical vapor deposition (CVD).The structures investigated in this study consisted of Si1-xGex[x=0.16]/Si1-xGex[x= 0.14, 0.13, 0.12, 0.10, 0.09, 0.07, 0.05, 0.04, 0.005, 0]/epi-Si/substrate heterolayers grown by CVD. The Si1-xGex layers were isochronally grown [t = 0.4 minutes per layer], with gas-flow rates being adjusted to control composition. Cross-section TEM specimens were prepared in the 110 geometry. These were then analyzed using two-beam bright-field, dark-field and weak-beam images. A JEOL JEM 200CX transmission electron microscope was used, operating at 200 kV.


Author(s):  
C.L. Briant

Grain boundary segregation is the process by which solute elements in a material diffuse to the grain boundaries, become trapped there, and increase their local concentration at the boundary over that in the bulk. As a result of this process this local concentration of the segregant at the grain boundary can be many orders of magnitude greater than the bulk concentration of the segregant. The importance of this problem lies in the fact that grain boundary segregation can affect many material properties such as fracture, corrosion, and grain growth.One of the best ways to study grain boundary segregation is with Auger electron spectroscopy. This spectroscopy is an extremely surface sensitive technique. When it is used to study grain boundary segregation the sample must first be fractured intergranularly in the high vacuum spectrometer. This fracture surface is then the one that is analyzed. The development of scanning Auger spectrometers have allowed researchers to first image the fracture surface that is created and then to perform analyses on individual grain boundaries.


Author(s):  
Peter Pegler ◽  
N. David Theodore ◽  
Ming Pan

High-pressure oxidation of silicon (HIPOX) is one of various techniques used for electrical-isolation of semiconductor-devices on silicon substrates. Other techniques have included local-oxidation of silicon (LOCOS), poly-buffered LOCOS, deep-trench isolation and separation of silicon by implanted oxygen (SIMOX). Reliable use of HIPOX for device-isolation requires an understanding of the behavior of the materials and structures being used and their interactions under different processing conditions. The effect of HIPOX-related stresses in the structures is of interest because structuraldefects, if formed, could electrically degrade devices.This investigation was performed to study the origin and behavior of defects in recessed HIPOX (RHIPOX) structures. The structures were exposed to a boron implant. Samples consisted of (i) RHlPOX'ed strip exposed to a boron implant, (ii) recessed strip prior to HIPOX, but exposed to a boron implant, (iii) test-pad prior to HIPOX, (iv) HIPOX'ed region away from R-HIPOX edge. Cross-section TEM specimens were prepared in the <110> substrate-geometry.


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