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

What Happened to Mine?: A History of Black Reparations in the United States

Senior Project submitted to The Division of Social Studies of Bard College

Porcelain Atrium: A Case Report with Literature Review

Massive left atrial wall calcification, or porcelain atrium, is very rare. We describe a case of an unusual pattern of cardiac calcification demonstrated on routine preoperative chest X-ray for cataract surgery in a 71-year-old Nigerian woman. Past medical history was significant for mitral stenosis and atrial fibrillation. Radiographic imaging revealed curvilinear high density areas of calcification outlining the left atrium on the chest X-ray. Noncontrast CT scan of the thorax confirmed the left atrial distribution of calcification and, thus, the diagnosis of porcelain left atrium

The creation and persistence of a misaligned gas disc in a simulated early-type galaxy

Massive early-type galaxies commonly have gas discs which are kinematically misaligned with the stellar component. These discs feel a torque from the stars and the angular momentum vectors are expected to align quickly. We present results on the evolution of a misaligned gas disc in a cosmological simulation of a massive early-type galaxy from the Feedback In Realistic Environments project. This galaxy experiences a merger which, together with a strong galactic wind, removes most of the original gas disc. The galaxy subsequently reforms a gas disc through accretion of cold gas, but it is initially 120 degrees misaligned with the stellar rotation axis. This misalignment persists for about 2 Gyr before the gas-star misalignment angle drops below 20 degrees. The time it takes for the gaseous and stellar components to align is much longer than previously thought, because the gas disc is accreting a significant amount of mass for about 1.5 Gyr after the merger, during which the angular momentum change induced by accreted gas dominates over that induced by stellar torques. Once the gas accretion rate has decreased sufficiently, the gas disc decouples from the surrounding halo gas and realigns with the stellar component in about 6 dynamical times. During the late evolution of the misaligned gas disc, the centre aligns faster than the outskirts, resulting in a warped disc. We discuss the observational consequences of the long survival of our misaligned gas disc and how our results can be used to calibrate merger rate estimates from observed gas misalignments.Comment: 10 pages, 7 figures. Accepted for publication in MNRAS. Revised version: minor changes. A movie of the evolution of the gas disc can be viewed at http://astro.berkeley.edu/~freeke/misalign.htm

Multilingual Semantic Relatedness using Lightweight Machine Translation

Distributional semantic models are strongly dependent on the size and the quality of the reference corpora, which embeds the commonsense knowledge necessary to build comprehensive models. While high-quality texts containing large-scale commonsense information are present in English, such as Wikipedia, other languages may lack sufficient textual support to build distributional models. This paper proposes using the combination of a lightweight (sloppy) machine translation model and an English Distributional Semantic Model (DSM) to provide higher quality word vectors for languages other than English. Results show that the lightweight MT model introduces significant improvements when compared to language-specific distributional models. Additionally, the lightweight MT outperforms more complex MT methods for the task of word-pair translation