Retardation analytical model to extend service life

A fatigue crack growth model that incorporates crack growth retardation effects and is applicable to the materials characteristics and service environments of high performance LH2/LO2 engine systems is discussed. Future Research plans are outlined

Controlling ion transport through nanopores: modeling transistor behavior

We present a modeling study of a nanopore-based transistor computed by a mean-field continuum theory (Poisson-Nernst-Planck, PNP) and a hybrid method including particle simulation (Local Equilibrium Monte Carlo, LEMC) that is able to take ionic correlations into account including finite size of ions. The model is composed of three regions along the pore axis with the left and right regions determining the ionic species that is the main charge carrier, and the central region tuning the concentration of that species and, thus, the current flowing through the nanopore. We consider a model of small dimensions with the pore radius comparable to the Debye-screening length ($R_{\mathrm{pore}}/\lambda_{\mathrm{D}}\approx 1$), which, together with large surface charges provides a mechanism for creating depletion zones and, thus, controlling ionic current through the device. We report scaling behavior of the device as a function the $R_{\mathrm{pore}}/\lambda_{\mathrm{D}}$ parameter. Qualitative agreement between PNP and LEMC results indicates that mean-field electrostatic effects determine device behavior to the first order

Method of assembling a thermal expansion compensator

A thermal expansion compensator is provided and includes a first electrode structure having a first surface, a second electrode structure having a second surface facing the first surface and an elastic element bonded to the first and second surfaces and including a conductive element by which the first and second electrode structures electrically and/or thermally communicate, the conductive element having a length that is not substantially longer than a distance between the first and second surfaces

Thermal expansion compensator having an elastic conductive element bonded to two facing surfaces

A thermal expansion compensator is provided and includes a first electrode structure having a first surface, a second electrode structure having a second surface facing the first surface and an elastic element bonded to the first and second surfaces and including a conductive element by which the first and second electrode structures electrically and/or thermally communicate, the conductive element having a length that is not substantially longer than a distance between the first and second surfaces

Analysis of the Minimal Promoter from the Hatching Enzyme a Gene

Hatching, defined as a biochemical or biophysical mechanism that allows the embryo to leave its protective envelope, is found in most animals. In fish, reptiles and amphibians, mostly oviparous animals, this means the emergence of the embryo from an egg. In mammals, viviparous animals, hatching is performed by the blastocyst in order to shed the zona pellucida. Fish, an oviparous animal, takes advantage of a biochemical mechanism in order to hatch and emerge from their chorion, or egg envelope. The mechanism includes the use of hatching enzymes that are secreted in order to digest the envelope membrane. The genes controlling the expression of these enzymes are transcribed and translated early in development and are secreted from the animal itself to perform their function. The gene, which controls expression of the protein, is in turn regulated by an upstream region called the promoter. It is the main goal of this project to clone and characterize the minimal promoter of the hatching enzyme gene within the Danio rerio, zebrafish, genome. This fragment will contain all the necessary regulatory elements to bind transcription factors and drive gene expression. The identification and analysis of the minimal promoter of the hatching enzyme gene can lead to the construction of a molecular tool that consists of a short promoter and reporter gene, to be used in conjunction with a variety of genetic screen

High Temperature Stable Nanocrystalline SiGe Thermoelectric Material

A method of forming a nanocomposite thermoelectric material having microstructural stability at temperatures greater than 1000 C. The method includes creating nanocrystalline powder by cryomilling. The method is particularly useful in forming SiGe alloy powder

Transport of solvated ions in nanopores: Asymptotic models and numerical study

Improved Poisson--Nernst--Planck systems taking into account finite ion size and solvation effects provide a more accurate model of electric double layers compared to the classical setting. We introduce and discuss several variants of such improved models. %Based on spatially fully resolved numerical models We study the effect of improved modeling in large aspect ratio nanopores. Moreover, we derive approximate asymptotic models for the improved Poisson--Nernst--Planck systems which can be reduced to one-dimensional systems. In a numerical study, we compare simulation results obtained from solution of the asymptotic 1D-models with those obtained by discretization of the full resolution models

Opinions about Smoking, Secondhand Smoke Exposure, and Smoking Behaviors of Freshmen College Students

The purpose of this project was to assess first semester freshman college students’ opinions about smoking, secondhand smoke exposure, and smoking behaviors on a smoke-free campus. This research used an online cross-sectional survey. For two years, surveys were emailed via Zoomerang to all first semester freshmen students at Valparaiso University. Survey questions contained 60 forced-choice or open-ended options. Data were analyzed using descriptive statistics. A total of 630 students responded. Subjects were primarily female (58.4%) and Caucasian (84.9%). Twenty-five percent of the respondents reported being exposed to secondhand smoke in their environments. Twenty-nine percent were unaware that the campus is a smoke-free environment, 79% have seen smoking on campus, and 25% believed the smoke-free policy is not enforced. Seventy-seven percent of the respondents agreed or strongly agreed that the campus should be a smoke-free environment. Thirty-four percent of respondents admitted to smoking at some point in their lifetime. Fourteen percent (n=91) indicated that they had smoked during the previous 30 days, with only 28% of these identifying themselves as “current” smokers. The majority of the respondents supported a smoke-free environment and believed the current campus policy is enforced. Data from this study will add to the growing body of evidence about college students’ smoking behaviors