The Crystal Growth of Cesium Cerium Chloride Scintillator for X-Ray and Gamma-Ray Spectroscopy Applications

The detection and identification of sources of nuclear radiation is an integral tool in defending our nation from threats of nuclear terrorism as well as enforcement of nuclear non-proliferation agreements around the globe. To improve the capabilities in this application, new detection materials surpassing the performance of existing technology utilizing sodium iodide [NaI:Tl] scintillator crystals must be developed and their production cost lowered to meet the demand for the large volumes required. A recently discovered intrinsic scintillation material in the form of crystalline cesium cerium chloride (CsCe2Cl7) has demonstrated promising performance in the detection of X-ray and gamma ray radiation. In order to assess the potential of this material to be developed into larger scale growth of crystals greater than one cubic inch in volume, research into optimizing the growth processes at smaller volumes is necessary. Single crystalline boules of CsCe2Cl7 were grown from the melt in sealed fused silica ampoules using the Bridgman method of crystal growth. A transparent growth furnace along with continuous observation apparatus were developed to aid in the investigation of the growth processes. A comparison of growth and cracking behavior under varied conditions was produced and growth protocols identified which improve crystal boule quality. Crystal quality benefits from controlling the self-seeding process through manipulation and control of critical freezing point isotherms during growth. Cracking appears to originate from aggressive detachment of the crystal from the fused silica ampoule wall while inclusions formed during growth by constitutional supercooling of the melt introduce additional crack nucleation sites through action as stress intensifiers within the bulk matrix. Reducing ampoule volume has a minor effect on cracking severity while additions of excess cesium chloride to the initial mixture produce a greater reduction in cracking. The anisotropic coefficients of thermal expansion as well as the refined crystal structure of cesium cerium chloride have been determined through single crystal Laue and temperature dependent powder X-ray diffraction pattern analyses respectively

Material and Process Engineering for Bulk Single Crystal Growth of High Performance Scintillator Potassium Calcium Iodide

Protection against threats of nuclear terrorism relies on the deployment of an enormous number of radiation detection devices with energy resolution to differentiate the radiological signatures of special nuclear materials amongst naturally occurring radiation and other nuisance sources. The capabilities of these devices rely upon the availability of high performance scintillator and semiconductor materials which provide useful responses in the presence of radiation. So far, few materials have been developed to a level that can supplant the use of underperforming NaI:Tl [thallium doped sodium iodide] crystals in the field due to their high cost and/or low yields of production. KCaI3[potassium calcium tri-iodide] doped with divalent europium has shown significant promise as a high performance scintillator and development to explore its potential for large scale production is necessary. KCaI3 crystallizes into an orthorhombic symmetry and exhibits a moderate amount of anisotropy in thermal expansion between its melting point of 524°C [Celsius] and room temperature. Production of large single crystals up to 1.5” in diameter can be facilitated through the vertical Bridgman method of melt growth using pyrolytic carbon-coated ampoules which eliminate cracking upon cooling. Low dopant amounts of 0.5-1.0 at% of Eu can achieve excellent energy resolutions of 3-4% at 662 keV while minimizing deleterious self-absorption effects, making it comparable to the highest performing scintillators discovered. A purpose-built multi-ampoule growth station was constructed and through the course of the investigation, a process was developed whereby several high quality, uncracked KCaI3 crystals at 1” in diameter could be grown simultaneously, in parallel, using a randomly oriented self-seeded approach. The demonstration shows great promise as a potential pathway to reduce the costs of scintillator production that is limited to a large number of boules at the 1”- 2” diameter size. Furthermore, KCaI3 possesses internal radioactivity due to the presence of naturally abundant 40K [potassium – 40] and will restrict its utility to applications where an elevated background is not critical. A significant obstacle to production of KCaI3 crystals doped with europium is the uniform distribution of the activator which can result in concentration gradients in bulk crystals and degrade spectroscopic performance

Understanding the Impact of Microenterprise on Community Capacity Development

In the summer of 2018 the non-profit, Just Like My Child Foundation (JLMC) contracted four graduate students to conduct a monitoring and evaluation project on the community level impact of a female empowerment program in Luwero, Uganda. During their time in country, the researchers conducted their own personal research on the impact of a dairy goat microenterprise program called the Livelihood Project. The purpose of this study is to understand how the Livelihood Project influenced community capacity development through the development of human, social, and financial capital. The Livelihood Project was completed in partnership with JLMC, Heifer International, and the local hospital. The Livelihood Project provided a loan of dairy goats and seeds, along with the relevant training to families infected/affected with HIV/AIDS. To understand the impact of the Livelihood Project, four participant’s homes were visited and a total of 26 semi-structured interviews were conducted. From the responses, the researchers concluded that human capital developed as participants increased their knowledge, skills, and abilities. Social capital increased as participants family’s incomes increased. Increased incomes increased family’s access to medicine and school. The researchers concluded that teaching agriculture can be used as a method to teach other intrapersonal skills such as commitment and time management. Because of this, NGOs and other development organizations should invest in an agricultural vocational school to help increase opportunities for individuals to learn technical agriculture skills and other life skills. Further, the increased social capital in the community created an environment conducive to starting cooperatives. The researcher suggests that companies invest in and partner with foreign cooperatives as a form of foreign aid. Finally, the researcher concluded that as financial capital increased, the quality of life of the participants improved as they had access to more resources. The researcher suggests the farmers create community lending programs to help reach the poorer community members who did not meet the qualifications to participate in the livelihood project

Seeking Justice and Defending the Oppressed: The Protestant Church’s Role in Racial Reconciliation

Systemic racial injustice affects every area of life, including religion. The history of the Protestant church is fraught with a habit to hurt more than help in this regard. The demographics, rhetoric, and culture of a church can contribute to racial superiority among white members and lead to an incorrect reading of scripture that supports racial injustice. This paper analyzes the ways in which Sojourn Midtown Community Church in Louisville, Kentucky, has used relationships, leadership, and worship to reflect attitudes of racial reconciliation

Understanding the Impact of Microenterprise on Community Capacity Development

In the summer of 2018 the non-profit, Just Like My Child Foundation (JLMC) contracted four graduate students to conduct a monitoring and evaluation project on the community level impact of a female empowerment program in Luwero, Uganda. During their time in country, the researchers conducted their own personal research on the impact of a dairy goat microenterprise program called the Livelihood Project. The purpose of this study is to understand how the Livelihood Project influenced community capacity development through the development of human, social, and financial capital. The Livelihood Project was completed in partnership with JLMC, Heifer International, and the local hospital. The Livelihood Project provided a loan of dairy goats and seeds, along with the relevant training to families infected/affected with HIV/AIDS. To understand the impact of the Livelihood Project, four participant’s homes were visited and a total of 26 semi-structured interviews were conducted. From the responses, the researchers concluded that human capital developed as participants increased their knowledge, skills, and abilities. Social capital increased as participants family’s incomes increased. Increased incomes increased family’s access to medicine and school. The researchers concluded that teaching agriculture can be used as a method to teach other intrapersonal skills such as commitment and time management. Because of this, NGOs and other development organizations should invest in an agricultural vocational school to help increase opportunities for individuals to learn technical agriculture skills and other life skills. Further, the increased social capital in the community created an environment conducive to starting cooperatives. The researcher suggests that companies invest in and partner with foreign cooperatives as a form of foreign aid. Finally, the researcher concluded that as financial capital increased, the quality of life of the participants improved as they had access to more resources. The researcher suggests the farmers create community lending programs to help reach the poorer community members who did not meet the qualifications to participate in the livelihood project

Reliability estimation based on operational data of manufacturing systems

Maintenance management has a direct influence on equipment reliability and safety. However, a large portion of traditional maintenance models and reliability analysis methods usually assumes that only perfect maintenance is performed on the system and the system will restore to as good as new regardless of the kind of preventive maintenance work-order that is performed. This is not practical in reality and may result in an inaccurate parametric estimation. The research objective of this paper is to develop a maximum likelihood estimation method to obtain more accurately estimated parameters based on the operational data of manufacturing systems, taking into consideration the difference between perfect and imperfect maintenance work-orders. Weibull distribution is specifically studied for this purpose. A practical case study based on industrial operational data from an automotive assembly line is performed to illustrate the implementation and efficiency of the proposed reliability estimation method. Copyright © 2008 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/61212/1/959_ftp.pd

Characterization of Hypertension Risk Factors at the Committee on Temporary Shelter

Introduction: The health of homeless populations is at risk due to a high prevalence of undiagnosed hypertension (HTN) and cardiovascular disease (CVD). The interaction of housing and socioeconomic status with the risk factors for HTN and CVD remains unclear. Prevention of HTN through a healthy diet, exercise, adequate sleep, and avoidance of tobacco has been well described, but financial limitations and competing priorities for shelter and food make blood pressure (BP) control difficult for this population. By characterizing the risk factors and awareness of hypertension within the homeless population at the Committee on Temporary Shelter Daystation (COTS) in Burlington, Vermont, we may be able to identify promising avenues for therapeutic intervention.https://scholarworks.uvm.edu/comphp_gallery/1226/thumbnail.jp

Antitumor activity and safety of the PARP inhibitor rucaparib in patients with high grade ovarian carcinoma and a germline or somatic BRCA1 or BRCA2 mutation: integrated analysis of data from Study 10 and ARIEL2

Objective: An integrated analysis was undertaken to characterize the antitumor activity and safety profile of the oral poly(ADP-ribose) polymerase inhibitor rucaparib in patients with relapsed high-grade ovarian carcinoma (HGOC). Methods: Eligible patients from Study 10 (NCT01482715) and ARIEL2 (NCT01891344) who received a starting dose of oral rucaparib 600 mg twice daily (BID) with or without food were included in these analyses. The integrated efficacy population included patients with HGOC and a deleterious germline or somatic BRCA1 or BRCA2 (BRCA1/2) mutation who received at least two prior chemotherapies and were sensitive, resistant, or refractory to platinum-based chemotherapy. The primary endpoint was investigator-assessed confirmed objective response rate (ORR). Secondary endpoints included duration of response (DOR) and progression-free survival (PFS). The integrated safety population included patients with HGOC who received at least one dose of rucaparib 600 mg BID, irrespective of BRCA1/2 mutation status and prior treatments. Results: In the efficacy population (n = 106), ORR was 53.8% (95% confidence interval [CI], 43.8–63.5); 8.5% and 45.3% of patients achieved complete and partial responses, respectively. Median DOR was 9.2 months (95% CI, 6.6–11.6). In the safety population (n = 377), the most frequent treatment-emergent adverse events (AEs) were nausea, asthenia/fatigue, vomiting, and anemia/hemoglobin decreased. The most common grade ≥ 3 treatment-emergent AE was anemia/hemoglobin decreased. Treatment-emergent AEs led to treatment interruption, dose reduction, and treatment discontinuation in 58.6%, 45.9%, and 9.8% of patients, respectively. No treatment-related deaths occurred. Conclusions: Rucaparib has antitumor activity in advanced BRCA1/2-mutated HGOC and a manageable safety profile