High-temperature thermal storage systems for advanced solar receivers materials selections

Advanced space power systems that use solar energy and Brayton or Stirling heat engines require thermal energy storage (TES) systems to operate continuously through periods of shade. The receiver storage units, key elements in both Brayton and Stirling systems, are designed to use the latent heat of fusion of phase-change materials (PCMs). The power systems under current consideration for near-future National Aeronautics and Space Administration space missions require working fluid temperatures in the 1100 to 1400 K range. The PCMs under current investigation that gave liquid temperatures within this range are the fluoride family of salts. However, these salts have low thermal conductivity, which causes large temperature gradients in the storage systems. Improvements can be obtained, however, with the use of thermal conductivity enhancements or metallic PCMs. In fact, if suitable containment materials can be found, the use of metallic PCMs would virtually eliminate the orbit associated temperature variations in TES systems. The high thermal conductivity and generally low volume change on melting of germanium and alloys based on silicon make them attractive for storage of thermal energy in space power systems. An approach to solving the containment problem, involving both chemical and physical compatibility, preparation of NiSi/NiSi2, and initial results for containment of germanium and NiSi/NiSi2, are presented

HIV-related stigma in the UK then and now: to what extent are we on track to eliminate stigma? A qualitative investigation

Background The introduction of effective antiretroviral treatment in the late 1990s led to the perception that HIV was a chronic but manageable condition. Nevertheless, stigma remains one of the major hurdles for people living with HIV (PLWH) to accessing healthcare and biomedical preventions. Thus, Fast Track Cities has set a target of zero HIV discrimination by 2030 as part of its strategy to end HIV transmission. Methods Fifty-three participants from the United Kingdom, including PLWH (n = 21, 40%), health and social care workers (n = 24, 45%), and charity workers and activists (n = 13, 25%), were recruited. Semi-structured interviews investigated stigma and discrimination, focusing on both before and after the widespread use of effective antiretroviral treatment in the late 1990s. Data were analysed using a thematic approach. Results Before effective antiretroviral treatment narratives were shaped by two main themes: 1) the media’s role in influencing public opinion and contributing to misunderstandings of HIV transmission; and 2) personal experiences of HIV-related stigma, which for PLWH included incidents of physical violence and aggression, as well as fears of their HIV status being publicised. Contemporary narratives on stigma experiences were organised around four themes: 1) discrimination in healthcare settings; 2) stigma amongst men who have sex with men (MSM); 3) stigma towards African and Afro-Caribbean PLWH; and 4) the limits of change in public HIV-related knowledge and attitudes. Contemporary narratives indicated a reduction in enacted stigma, but continued anticipation of discrimination and self-reported shame, particularly in MSM and African and Afro-Caribbean PLWH. Conclusion The nature of stigma against those with HIV has evolved. The intersection of PLWH and minority groups (e.g. MSM and African and Afro-Caribbean persons) may enhance anticipatory and internalised stigma, with some suggestion that this may contribute to reduced engagement in HIV care and prevention services. Our findings indicate the need for further research in this area, as well as proactive interventions with community groups to enhance knowledge of HIV

Development of surface treatments and alloy modifications for corrosion-resistant oxide scales

Alloys based on the long-range ordered system Fe{sub 3}Al are under development at Oak Ridge National Laboratory in support of coal conversion and combustion materials requirements. Of particular interest is the performance of these alloys in coal gasifiers involving product gases with relatively low oxygen activities and high sulfur activities. Using H{sub 2}S-H{sub 2}-H{sub 2}O gas mixtures, several experimental iron-aluminum alloys have been tested to assess the effects of aluminum concentration on oxidation-sulfidation response at 700 to 800{degree}C in a simulated gasifier environment. Metallographic and chemical analyses of the corrosion product scales and the underlying alloy were performed to determine the role of respective metallic elements on the sulfidation-oxidation processes. These results, together with thermogravimetric analyses, are discussed in terms of the apparent corrosion mechanisms and optimization of alloy composition for exposure to coal-derived environments. More recently, the corrosion performance of an Fe-28% Al-2% Cr alloy has been evaluated in gases produced by an operating gasifier. The reaction products and scale morphologies under actual service conditions were generally similar to the laboratory test results except for the presence of an ash deposit on the gasifier specimens. 2 refs., 7 figs., 4 tabs

AN EVALUATION OF ELECTRO-MACHINING FOR THE ANALYSIS OF METAL SURFACES

A procedure is described for the uniform removal of very thin sections of metal surfaces by electrolysis. Equipment requirements and the various parameters affecting operation are considered, and the results of applying the technique to studies of solid-state diffusion are discussed. The technique appears to offer considerable promise for evaluating chemical changes at metal surfaces which have taken place as a result of corrosion or diffusion processes. (auth

CHANGING WHILE STANDING STILL: OPERATIONAL DEVELOPMENT DURING TRENCH WARFARE PERIOD OF THE KOREAN WAR, 1951 – 1953

Master'sMASTER OF ART

Correlates of Homeless Episodes among Indigenous People

This study reports the correlates of homeless episodes among 873 Indigenous adults who are part of an ongoing longitudinal study on four reservations in the Northern Midwest and four Canadian First Nation reserves. Descriptive analyses depict differences between those who have and have not experienced an episode of homelessness in their lifetimes. Multivariate analyses assess factors associated with a history of homeless episodes at the time of their first interview. Results show that individuals with a history of homeless episodes had significantly more individual and family health, mental health, and substance abuse problems. Periods of homelessness also were associated with financial problems. Among the female caretakers who experienced episodes of homelessness over the course of the study, the majority had been homeless at least once prior to the start of the study and approximately one–fifth met criteria for lifetime alcohol dependence, drug abuse, or major depression. Family adversity during childhood was also common for women experiencing homelessness during the study

Correlates of Homeless Episodes among Indigenous People

This study reports the correlates of homeless episodes among 873 Indigenous adults who are part of an ongoing longitudinal study on four reservations in the Northern Midwest and four Canadian First Nation reserves. Descriptive analyses depict differences between those who have and have not experienced an episode of homelessness in their lifetimes. Multivariate analyses assess factors associated with a history of homeless episodes at the time of their first interview. Results show that individuals with a history of homeless episodes had significantly more individual and family health, mental health, and substance abuse problems. Periods of homelessness also were associated with financial problems. Among the female caretakers who experienced episodes of homelessness over the course of the study, the majority had been homeless at least once prior to the start of the study and approximately one–fifth met criteria for lifetime alcohol dependence, drug abuse, or major depression. Family adversity during childhood was also common for women experiencing homelessness during the study

Would Surgeons Opt for Polypropylene Mesh if They Hypothetically Had Stress Urinary Incontinence or Pelvic Organ Prolapse?

Introduction • Controversy surrounding vaginal mesh kits • Many patients have negative connotations regarding mesh • If patients were shown that their surgeons would opt for mesh –maybe this would help lessen the negativity?https://knowledgeconnection.mainehealth.org/lambrew-retreat-2021/1057/thumbnail.jp

Factors Associated with Growth in Daily Smoking among Indigenous Adolescents

North American Indigenous adolescents smoke earlier, smoke more, and are more likely to become regular smokers as adults than youth from any other ethnic group yet we know very little about their early smoking trajectories. We use multilevel growth modeling across five waves of data from Indigenous adolescents (aged 10 to 13 years at Wave 1) to investigate factors associated with becoming a daily smoker. Several factors, including number of peers who smoked at Wave 1 and meeting diagnostic criteria for major depressive episode and conduct disorder were associated with early daily smoking. Only age and increases in the number of smoking peers were associated with increased odds of becoming a daily smoker