Automated Source-Detector Positioner for Radiation Detection

The Nuclear Engineering Department at Virginia Commonwealth University has an unmet need for an automated source detector positioner for radiation detection experiments that are carried out in lab work. During radiation data collection in radiation detection systems it is of the utmost importance that radioactive samples are positioned and moved with the highest degree of precision possible. This high degree of precision allows for more meaningful data to be collected. The current methods employed by the Nuclear Engineering Department are not as accurate as they can be due to the fact the the current detection systems are manual. Furthermore they are aligned only by sight and have fixed shelving positions. The figure below is the solution to this issue: An automated Source-Detector Positioner for Radiation Detection. This detection system has been design to have a low tolerance so that radiation samples are always centered in the “Sample holder/clamp” over the radiation detector probe. Two stepper motors move along rods, lifting or lowering the sample holder to the desired position over the radiation detection probe. There is also an optional shielding component for the limitation of radiation emission that improves on the shelving method from previous devices. This is all supported with 3D printed rings and metal rods.https://scholarscompass.vcu.edu/capstone/1208/thumbnail.jp

Daze fasteners

A daze fastener system for connecting two or more structural elements wherein the structural elements and fastener parts have substantially different coefficient of thermal expansion physical property characteristics is employed in this invention. By providing frusto-conical abutting surfaces between the structural elements and fastener parts any differences in thermal expansion/contraction between the parts is translated to sliding motion and avoids deleterious thermal stresses in the connection. An essential feature for isotropic homogeneous material connections is that at least two sets of mating surfaces are required wherein each set of mating surfaces has line element extensions that pass through a common point

Doctor of Philosophy

dissertationThe Hox Complex is a matrix of 38 transcription factor genes that play a role in the proper development of the vertebrate body plan by specifying regional information along the embryonic axes. The 5' Hox D genes are a subset of this complex that are strongly expressed in the limb buds during embryogenesis, suggesting that they influence the appendicular skeleton. A specific molecular combinatorial Hox code has been proposed as a model for the 5' Hox D genes in patterning the vertebrate limb. To test this model and resolve the role of these genes in development, a genetic analysis is performed by a mutational approach in the mouse. Specifically, the technique of gene targeting is employed to generate mice individually mutant for hoxd-11, hoxd-12, and hoxd-13. These strains have urogenital tract defects (often resulting in sterility), axial homeosis at the lumbar-sacral region, and malformations in the limb skeleton. The limb phenotypes, however, do not resemble any apparent homeotic transformations as predicted by the combinatorial codes but rather are the result of regional malformations in the shapes, length, and segmentation of bones. To extend these findings, the strains are crossed to each other and to other Hox-deficient mice to produce animals with various combinations of mutant alleles. The phenotypes in these animals are more dramatic demonstrating functional redundancy and genetic interaction, especially in the limb. The data allow for a new interpretation where the Hox D genes regulate cell proliferation in a proximodistal direction during growth of the limb bud. As such, these genes may not code for distinct positional information, per se, but rather contribute to the number of cells required for proper limb construction. The results are discussed in the context of three models for generating a limb pattern in vertebrates

Foraging along blue highways : seasonality and subsistence strategies in the Middle Stone Age of Ethiopia

Modern humans originated in Africa ~200-300,000 years ago (ka) during the Middle Stone Age (MSA; ~320-45 ka), and during this period developed complex foraging behaviors that facilitated their later expansion out of Africa and across the world. Studying early human behavior in the MSA is therefore critical to understanding how modern humans adapted to diverse environments and refining current models of human dispersal out of Africa. Previous work has provided valuable insight into MSA behaviors, but important questions remain, and additional data from sites sampling diverse habitats are necessary to understand the full range of MSA behavioral variability and test hypotheses about late Pleistocene human behavioral evolution and dispersal. This dissertation uses faunal remains from SM1 (> 40-60 ka), an open-air site located in NW Ethiopia, to investigate human behavior during the late MSA. Ongoing excavations at SM1 have recovered thousands of lithics and faunal remains deposited over multiple seasons of occupation at a time when seasonality and aridity in the region were at least as extreme as today. Zooarchaeological and taphonomic analyses make it possible to reconstruct site formation processes and human foraging behavior, and document diverse terrestrial vertebrates, fish, and mollusks at the site. Taxa present include bovids, suids, primates, hares, rodents, reptiles, amphibians, and birds, as well as multiple families of catfish, and several cyprinid and cichlid fish genera. Taphonomic analyses document abundant evidence for human accumulation of terrestrial fauna and fish, and moderate damage by non-human agents and processes. Results indicate that foraging behavior was seasonally structured, with an emphasis on hunting small-to-medium-sized terrestrial prey and regular fishing and aquatic foraging during the dry season. Comparative data from MSA sites in Ethiopia, Morocco, and South Africa indicate that taphonomic signatures from SM1 are most similar to other open-air sites, and quite different from cave sites, and suggest caution when interpreting human behavior at open-air sites based on criteria derived largely from caves. Results offer valuable insight into late MSA human behavior in this understudied region of the Horn of Africa, and provide a taphonomic baseline for future studies of open-air MSA sites in AfricaAnthropolog

The Rationality of Plato’s Theory of Good and Evil

Plato has been called the “father of rational theology.” This thesis is an attempt to examine in the light of contemporary Platonic scholarship five of Plato’s essentially religious doctrines insofar as they support the idea that Plato’s theory of good and evil is rational. Chapters 1 and 2 examine the plausibility of Plato’s theory of knowledge. Chapter 3 states briefly his theory of Forms, while Chapter 4 attempts to give this doctrine credence by analysing those aspects of it which seem least convincing. Chapters 5 and 6 consider Plato’s theory of soul and conclude that, although some of his beliefs in this area lack credibility, his interpretation of the nature and function of soul is basically plausible. Chapters 7 and 8 examine the rationality of Plato’s Idea of the Good. Chapter 9 sketches his notion of balance and proportion and, in conclusion, Chapter 10 attempts to show how this theory provides an underlying credibility not only to all the theories discussed but also to Plato’s theory of good and evil in its entirety

RISK AND RETURN TO IP GRAIN PRODUCTION: THE CASE OF HIGH OIL CORN

Returns for soybeans, commodity corn and high oil corn under an export and domestic market buyer's-call contract were simulated. High oil corn is competitive with commodity corn when yield drag is two percent and bundling reduces seed cost. Commodity loan rate is important in reducing high oil corn price risk.Crop Production/Industries,

Cryogenic Insulation System

This invention relates to reusable, low density, high temperature cryogenic foam insulation systems and the process for their manufacture. A pacing technology for liquid hydrogen fueled, high speed aircraft is the development of a fully reusable, flight weight cryogenic insulation system for propellant tank structures. In the invention cryogenic foam insulation is adhesively bonded to the outer wall of the fuel tank structure. The cryogenic insulation consists of square sheets fabricated from an array of abutting square blocks. Each block consists of a sheet of glass cloth adhesively bonded between two layers of polymethacrylimide foam. Each block is wrapped in a vapor impermeable membrane, such as Kapton(R) aluminum Kapton(R), to provide a vapor barrier. Very beneficial results can be obtained by employing the present invention in conjunction with fibrous insulation and an outer aeroshell, a hot fuselage structure with an internal thermal protection system

The history and invocation of the Arche in Austrian Radical architecture thinking

The architecture of the European Radical movements of the 1960s and 1970s is principally associated with the forward-looking principles of the architectural avant-garde. Scholarship on the movements emphasizes its futuristic and accompanying science fiction elements. While the importance of a visionary focus on the birth and development of the Radical movements is widely acknowledged, the same cannot be said for the connections of the visionary production to the architectural past. This article focuses on the Austrian Radicals and stresses their use of archetypal forms as a means to signify the difference between them and the preceding generation of Austrian modernists. In this sense the passing of editorial control of Bau from the Modernists to the Radicals is a crucial moment in the context of this article

Morphologically complex words in L1 and L2 processing: Evidence from masked priming experiments in English

This paper reports results from masked priming experiments investigating regular past-tense forms and deadjectival nominalizations with -ness and -ity in adult native (L1) speakers of English and in different groups of advanced adult second language (L2) learners of English. While the L1 group showed efficient priming for both inflected and derived word forms, the L2 learners demonstrated repetition-priming effects (like the L1 group), but no priming for inflected and reduced priming for derived word forms. We argue that this striking contrast between L1 and L2 processing supports the view that adult L2 learners rely more on lexical storage and less on combinatorial processing of morphologically complex words than native speakers.</jats:p