Design of inflatable solar concentrator

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 115-116).Solar concentrators improve the performance of solar collection systems by increasing the amount of usable energy available for a given collector size. Unfortunately, they are not known for their light weight and portability, which is ideal for basic applications like solar cooking. The goal of the project was to a design a light-weight and portable solar concentrator with minimal tracking requirements. The concept of an inflatable compound parabolic concentrator was developed, which required modifying the theoretical profile geometry. An analytical model was created to predict the efficiency of the system for different design parameter configurations. The model was used to develop a design and manufacturing process which was used to design and manufacture small-scale and full-scale prototypes. Experiments were designed to test the performance of the concentrators and the test results were used to determine a model accuracy of 11.4 1.3 % and 1.9±1.6% using the small-scale prototype and full-scale prototype, respectively.by Omar Carrasquillo.S.M

Design and implementation of control system for magnetic suspension device

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 57).The purpose of this thesis was to gain more knowledge and experience in the areas of modeling, dynamics, and applied control theory. A single-axis magnetic suspension device originally designed by Professor David Trumper for classroom demonstrations was chosen to improve the understanding of the previously mentioned topics. The dynamics of these types of systems provide interesting control challenges due to the nonlinear nature of its dynamics. As a result, designing of a control system for this device required the understanding and experimentation of two nonlinear controls techniques: linearization of the plant around an operating point, and feedback linearization. A combination of electromagnetic theory and experimentation was used to model the suspension actuator, and two different controllers were designed and implemented using the different controls methods.by Omar Carrasquillo.S.B

Space Station Freedom environmental control and life support system phase 3 simplified integrated test detailed report

A description of the phase 3 simplified integrated test (SIT) conducted at the Marshall Space Flight Center (MSFC) Core Module Integration Facility (CMIF) in 1989 is presented. This was the first test in the phase 3 series integrated environmental control and life support systems (ECLSS) tests. The basic goal of the SIT was to achieve full integration of the baseline air revitalization (AR) subsystems for Space Station Freedom. Included is a description of the SIT configuration, a performance analysis of each subsystem, results from air and water sampling, and a discussion of lessons learned from the test. Also included is a full description of the preprototype ECLSS hardware used in the test

Space Station CMIF extended duration metabolic control test

The Space Station Extended Duration Metabolic Control Test (EMCT) was conducted at the MSFC Core Module Integration Facility. The primary objective of the EMCT was to gather performance data from a partially-closed regenerative Environmental Control and Life Support (ECLS) system functioning under steady-state conditions. Included is a description of the EMCT configuration, a summary of events, a discussion of anomalies that occurred during the test, and detailed results and analysis from individual measurements of water and gas samples taken during the test. A comparison of the physical, chemical, and microbiological methods used in the post test laboratory analyses of the water samples is included. The preprototype ECLS hardware used in the test, providing an overall process description and theory of operation for each hardware item. Analytical results pertaining to a system level mass balance and selected system power estimates are also included

Addressing the disparities in dementia risk, early detection and care in Latino populations: Highlights from the second Latinos & Alzheimer\u27s Symposium

The Alzheimer\u27s Association hosted the second Latinos & Alzheimer\u27s Symposium in May 2021. Due to the COVID-19 pandemic, the meeting was held online over 2 days, with virtual presentations, discussions, mentoring sessions, and posters. The Latino population in the United States is projected to have the steepest increase in Alzheimer\u27s disease (AD) in the next 40 years, compared to other ethnic groups. Latinos have increased risk for AD and other dementias, limited access to quality care, and are severely underrepresented in AD and dementia research and clinical trials. The symposium highlighted developments in AD research with Latino populations, including advances in AD biomarkers, and novel cognitive assessments for Spanish-speaking populations, as well as the need to effectively recruit and retain Latinos in clinical research, and how best to deliver health-care services and to aid caregivers of Latinos living with AD

"It's making contacts" : notions of social capital and implications for widening access to medical education

Acknowledgements Our thanks to the Medical Schools Council (MSC) of the UK for funding Study A; REACH Scotland for funding Study B; and Queen Mary University of London, and to the medical school applicants and students who gave their time to be interviewed. Our thanks also to Dr Sean Zhou and Dr Sally Curtis, and Manjul Medhi, for their help with data collection for studies A and B respectively. Our thanks also to Dr Lara Varpio, Uniformed Services University of the USA, for her advice and guidance on collating data sets and her comments on the draft manuscript.Peer reviewedPublisher PD

Technical assessment of Mir-1 life support hardware for the international space station

NASA has been progressively learning the design and performance of the Russian life support systems utilized in their Mir space station. In 1992, a plan was implemented to assess the benefits of the Mir-1 life support systems to the Freedom program. Three primary tasks focused on: evaluating the operational Mir-1 support technologies and understanding if specific Russian systems could be directly utilized on the American space station and if Russian technology design information could prove useful in improving the current design of the planned American life support equipment; evaluating the ongoing Russian life support technology development activities to determine areas of potential long-term application to the U.S. space station; and utilizing the expertise of their space station life support systems to evaluate the benefits to the current U.S. space station program which included the integration of the Russian Mir-1 designs with the U.S. designs to support a crew of six

Submerged in the mainstream? A case study of an immigrant learner in a New Zealand primary classroom

Immigrant children from diverse language backgrounds face not only linguistic challenges when enrolled in mainstream English-medium classrooms, but also difficulties adjusting to an unfamiliar learning community. The culture of primary school classrooms in New Zealand typically reflects conventions across three dimensions: interactional, instructional task performance and cognitive-academic development. All three dimensions are underpinned by the culturally specific discourse conventions involved in language socialisation. New learners may be helped by classmates or their teacher to understand and successfully use these conventions, but left on their own they may sink rather than swim. This is a case study of one Taiwanese 11-year old boy, 'John', who entered a New Zealand primary classroom midway through the school year. John's basic conversational ability was sound, but he did not possess the interactive classroom skills needed to operate in the new culture of learning. Selected from a wider study of the classroom, transcript data from audio-recorded excerpts of John's interactions over several months with his teacher and classmates are interpreted from perspectives derived from sociocultural and language socialisation theories. The article concludes with a brief consideration of the extent to which John constructed, or was constrained from constructing meaningful learning experiences, and suggestions for further research and reflection

Child health insurance coverage: a survey among temporary and permanent residents in Shanghai

<p>Abstract</p> <p>Background</p> <p>Under the current healthcare system in China, there is no government-sponsored health insurance program for children. Children from families who move from rural and interior regions to large urban centres without a valid residency permit might be at higher risk of being uninsured due to their low socioeconomic status. We conducted a survey in Shanghai to describe children's health insurance coverage according to their migration status.</p> <p>Method</p> <p>Between 2005 and 2006, we conducted an in-person health survey of the adult care-givers of children aged 7 and under, residing in five districts of Shanghai. We compared uninsurance rates between temporary and permanent child residents, and investigated factors associated with child health uninsurance.</p> <p>Results</p> <p>Even though cooperative insurance eligibility has been extended to temporary residents of Shanghai, the uninsurance rate was significantly higher among temporary (65.6%) than permanent child residents (21.1%, adjusted odds ratio (OR): 5.85, 95% confidence interval (95% CI): 4.62–7.41). For both groups, family income was associated with having child health insurance; children in lower income families were more likely to be uninsured (OR: 1.96, 95% CI: 1.40–2.96).</p> <p>Conclusion</p> <p>Children must rely on their parents to make the insurance purchase decision, which is constrained by their income and the perceived benefits of the insurance program. Children from migrant families are at even higher risk for uninsurance due to their lower socioeconomic status. Government initiatives specifically targeting temporary residents and providing health insurance benefits for their children are urgently needed.</p

Elementos de construcción a partir de residuos de construcción y demolición en Bogotá

Trabajo de investigaciónEl sector de la construcción en la ciudad de Bogotá, ha crecido constantemente al igual que los Residuos de construcción y Demolición (RCD) que esta industria genera, debido a esta problemática se realiza una contextualización de los RCD que se generan en la ciudad de Bogotá, identificando su posible utilización como materia prima de nuevos elementos para esta industria por lo tanto se investiga en bases de datos que materiales se producen en la actualidad con los RCD y se presenta un análisis PESTEL identificando algunas variables macro económicas que pueden tener influencia en el aprovechamiento y comercialización de los materiales producidos a partir de RCD.INTRODUCCIÓN 1. GENERALIDADES 2. CARACTERIZACIÓN DE LOS RESIDUOS DE CONSTRUCCIÓN Y DEMOLICIÓN QUE SE GENERAN EN LA CIUDAD DE BOGOTÁ 3. MATERIALES QUE SE PRODUCEN A PARTIR DE RESIDUOS DE CONSTRUCCIÓN Y DEMOLICIÓN Y SUS COMPONENTES 4. DETERMINAR LA APLICABILIDAD DE LOS RCD PARA PRODUCTOS QUE SE PUEDEN REALIZAR DADA LA EXISTENCIA EN EL MERCADO 5. CONCLUSIONES 6. RECOMENDACIONES BIBLIOGRAFÍAPregradoIngeniero Civi