Extraction of SiO2/SiC interface trap profile in 4H- and 6H-SiC metal-oxide semiconductor field-effect transistors from subthreshold characteristics at 25°C and 150°C

The profile of trap density at the SiO₂/SiC interface in SiC metal-oxide semiconductor field-effect transistors (MOSFETs) is critical to study the channel electron mobility and evaluate device performance under various processing and annealing conditions. In this work, we report on our results in determining the interface trap density in 4H- and 6H-SiC MOSFETs annealed in dry O₂, NO, and CO₂, respectively, based on the device transfer and currentvoltage characteristics in the subthreshold region at 25°C and 150°C. We also studied electron field-effect mobility, fixed oxide charge, and gate leakage in those devices.     

Carton Clamp Test Methodologies and the Effects on Load Containment and Retention

A carton clamp is an alternative material handling device for moving packages and material. The need for changing the clamping force for variations in size, shape and weight of the load creates the potential for underclamping (slippage) and overclamping (compressive damage). Currently, there are two test standards that provide lab‐based forklift/clamp testing guidance – ISTA 3B and ASTM 6055. While ISTA provides a stationary simulation of carton clamp handling, ASTM offers a more mobile approach. The ISTA recommended testing equipment tends to be fairly expensive and is not easily accessible in North American test facilities. The ASTM standard proposes the use of a carton clamp truck in industry but does not specify any specific parameters making repeatability between laboratories and practitioners ambiguous. This study examined the implementation a carton clamp lift truck as found in industry allowing for mobile (hazard course) testing. A modified version of ISTA 3B was paired off against ASTM 6055 for evaluating both column and cross stack pallet patterns with a variety of treatments. This study attempted to determine if carton clamps as found in industry are capable and repeatable enough to provide consistent data. This study also examined the test methodologies' effect on load containment via stretch film force, load retention via unitized load slippage and the effects of ride height and driver interaction. The study sought to understand if these effects are uniform across the unitized load or if particular layers of the load are more affected than others. Copyright © 2014 John Wiley & Sons, Ltd.     

Microstructural Changes in Liquid-Phase-Sintered Silicon Carbide during Creep in an Oxidizing Environment

The knowledge of the microstructural evolution during exposure to high temperatures is important to understanding the mechanisms responsible for the creep resistance of silicon carbide (SiC) ceramics. This includes not only the phase transformation of the SiC grains, but also the phase transformations of the oxynitride grain-boundary phases. For this study, a series of SiC specimens were prepared with varying molar ratios of AlN-Y₂O₃ additives. Increased creep resistance was observed in specimens with an additive system containing a 2:3 molar ratio or 60 mol% Y₂O₃. A continuous oxide layer of Y₂Si₂O₇ formed at the surface during elevated temperature testing in air. No blistering or cracking was observed in this oxide coating. Further increase of the creep resistance was achieved by a post-sintering nitrogen anneal.     

Volatile compounds in light, medium, and dark black walnut and their influence on the sensory aromatic profile

Light, medium, and dark colored kernels from 3 different cultivars (Emma K, Kwik Krop, and Sparks 127) and one wild species of black walnut were studied for their aroma volatiles. Solid-phase microextraction-gas chromatography-mass spectrometry was used to determine the aromatic compounds present in the headspace of these samples. Partial least square regression was used to correlate the instrumental aromatic data with the sensory responses, obtained in a previous study, for the same samples. Thirty-four aromatic compounds were found in the black walnut cultivars, highlighting among them the presence of 14 esters. Although more than 50% of the total concentration of volatile compounds, esters were not important compounds in determining the differences in the sensory aromatic profiles of the 3 colors of the nuts. As a general trend, the concentration of total volatile compounds was always significantly higher in light black walnuts than in the medium colored samples; medium colored samples had higher volatile content than the dark black walnuts. The presence of hexanal was related to rancid and acrid aromas and was determined to differentiate the dark black walnuts from the medium and light colored samples. PRACTICAL APPLICATION: The data presented in this article will help understand the aromatic differences between light, medium, and dark colored kernels of domestic and wild black walnut. The aromatic profile of these nuts, not studied until this moment, can be used as a model to develop flavorings and new products by the food industries.     

Effect of the Hofmeister series on gluten aggregation measured using a high shear-based technique

This study investigated differences in gluten aggregation time and gluten strength using the Hofmeister series in high shear-treated slurries. Two flours (15.1% and 10.6% protein) were evaluated by using a Gluten Peak Tester (GPT). Hofmeister anions including NaF, NaCl, NaBr, NaI, and NaSCN at concentrations ranging from 0.1 to 1.0 M and cations including KCl, NaCl, NH₄Cl, MgCl₂, and CaCl₂ at concentrations ranging from 0.0625 to 1.0 M were used. The instrument applies high shear to a flour/salt solution slurry and measures torque and aggregation time to form gluten. Aggregation time using the GPT followed the order of the Hofmeister series, with minor effects at salt concentration < 0.3 M and increasing differences at higher salt concentrations. Torque increased with increasing concentration. Creating models of the trends using second and third order equations demonstrated that gluten aggregation follows a distinct natural law in the slurries. The study confirmed the potential of the high shear based method to be used a research tool to investigate gluten aggregation properties and to potentially predict functionality in baked product systems.     

Steady and Unsteady Forced Convective Heat Transfer Analysis in 180 Degree Bend

Abstract

Numerical studies on fluid flow and heat transfer through a two-dimensional 180-degree sharp bend are performed using an in-house code based on streamline upwind Petrov-Galerkin finite element method. A new geometric parameter called inlet height to outlet height ratio (IOR) is defined to assess the heat transfer performance. Parametric analyses are carried out by varying the Reynolds number (Re) from 100 to 900 for five IORs (1:2, 1:1.5, 1:1, 1.5:1, 2:1). The fluid flow changes from steady to unsteady for all IORs with increasing Re. The critical Reynolds number range is identified for each IOR and is found to be lower for IOR < 1 or IOR > 1 when compared with IOR 1:1, thus enhancing the heat transfer due to unsteadiness. IOR also influences the rate of generation of the vortices and the vortex interactions, which emphasize the enhancement in heat transfer. Nusselt number (Nu) and thermal performance factor (TPF) for the domain are calculated and it is observed that though there is an increase of 20%–40% in Nu for IOR 2:1 configuration with respect to IOR 1:1, the TPF predicts that IOR 1:1.5 is an overall good domain for heat transfer and pressure drop considerations.     

Microstructural Evolution Under Low Shear Rates During Rheo Processing of LM25 Alloy

Microstructural features of LM25 alloy processed by two different routes: (1) conventional casting, and (2) shear casting based on inclined heated surface are studied. The microstructures of the primary phase for the shear-cast samples show rosette or ellipsoidal morphologies. Heat transfer of contacting melt with the inclined tube surface and shear stress exerted on the layers of the melt as result of gravitational force are crucial parameters for the microstructural evolution. Compared to those produced by conventional casting, shear-cast samples have a much improved tensile strength and ductility due to globular microstructure.     

Design,simulation and performance analysis bio-sensors for the detection of cholera and diarrhea using MEMS technology

Microsystem Technologies - This paper presents two different types of micro channels namely one is cylindrical and the other is rectangular which are designed and simulated using FEM tool for the...     

Design and simulation of fixed–fixed flexure type RF MEMS switch for reconfigurable antenna

Microsystem Technologies - This Paper Presents the design and simulation of RF MEMS switch taken on Microstrip patch antenna loaded with the circular type CSRR. The Tunability of the patch antenna...