Vacuum-isolation vessel and method for measurement of thermal noise in microphones

The vacuum isolation vessel and method in accordance with the present invention are used to accurately measure thermal noise in microphones. The apparatus and method could be used in a microphone calibration facility or any facility used for testing microphones. Thermal noise is measured to determine the minimum detectable sound pressure by the microphone. Conventional isolation apparatus and methods have been unable to provide an acoustically quiet and substantially vibration free environment for accurately measuring thermal noise. In the present invention, an isolation vessel assembly comprises a vacuum sealed outer vessel, a vacuum sealed inner vessel, and an interior suspension assembly coupled between the outer and inner vessels for suspending the inner vessel within the outer vessel. A noise measurement system records thermal noise data from the isolation vessel assembly. A vacuum system creates a vacuum between an internal surface of the outer vessel and an external surface of the inner vessel. The present invention thus provides an acoustically quiet environment due to the vacuum created between the inner and outer vessels and a substantially vibration free environment due to the suspension assembly suspending the inner vessel within the outer vessel. The thermal noise in the microphone, effectively isolated according to the invention, can be accurately measured

Predictors Of Retention In Hiv/aids Care At The Yale-New Haven Hospital Nathan Smith Clinic: Exploratory Analysis Using The Community Careware Database

Background: A `test-and-treat\u27 strategy for HIV prevention in the United States is a method that was proposed in an effort to curb and reduce HIV transmission. However, the magnitude of the limitations observed at the various stages in the spectrum of engagement in care can threaten the `test-and-treat\u27 HIV prevention initiative because successful retention remains problematic. Based on the United States\u27 retention statistics, approximately one fourth to one half of those who were diagnosed with HIV were out-of-care. This figure suggests we need more information about the best ways to retain HIV-infected individuals in care. Objective: In order to determine the best methods to retain HIV positive patients in care over time, primary predictors driving or influencing HIV positive patients\u27 retention status must be assessed to better focus intervention strategies that would promote retention in care for those at high risk of falling out of care. This investigation sought to query into how one may employ the CAREWare database, used by Ryan White funded agencies, to study predictors of engagement in care at the Yale-New Haven Hospital Nathan Smith Clinic, which is the largest Ryan White funded clinic in Connecticut. The identification of key barriers influencing retention in care will allow health care providers and public health officials to devise a multidisciplinary team model that would specifically cater to the needs of HIV/AIDS patients at the Clinic, so that interventions may be aimed at optimizing the longitudinal care initiative and improving clinical health outcomes. Method & Materials: A cross-sectional study was conducted to identify key predictors associated with the retention status of HIV/AIDS patients who attended the Nathan Smith Clinic between October 1, 2011, and October 1, 2012. The timeframe of one year was chosen because the Health Resources and Services Administration (HRSA) definition of retention is, over a given year, an HIV/AIDS patient must have at minimum two primary care visits, with each visit being at least 3 months apart. Clients who failed to meet the HRSA retention definition were designated as out-of-care. The community CAREWare database and Logician (GE Centricity), the Yale-New Haven Hospital\u27s electronic medical records system, were employed to abstract patient information. The Pearson X2 and independent samples t-tests were used to assess the unadjusted associations between the patients\u27 baseline characteristics and retention status. Logistic regression analyses and a backward elimination method of selecting variables were utilized to discover potential contextual factors influencing retention in care. Results: From October 1, 2011 to October 1, 2012, 696 patients obtained outpatient HIV/AIDS primary care services at the Nathan Smith Clinic and were eligible for the study. Of this total, 134 (19.3%) HIV/AIDS clients were determined to be out-of-care under the HRSA definition for retention in care. The model selection technique yielded three statistically significant predictors of retention that best represented the data. Males were observed to be 1.81 times as likely to fall out-of-care compared to females [adjusted OR 95% CI (1.17, 2.82)]. Patients with no insurance [adjusted OR: 3.30, p=0.004], with private insurance [adjusted OR: 1.86, p=0.040] or with Medicaid [adjusted OR: 2.47, p=0.002] were at an increased risk of falling out-of-care compared to individuals with Medicare. Lastly, HIV/AIDS clients who had received none of the three HIV/AIDS support services (i.e. medical case management, mental health or substance abuse) had a 3.29 increased odds of falling out-of-care compared to individuals who had any one of the three support services [adjusted OR 95% CI (2.05, 5.26)]. Conclusions: These findings suggested that barriers affecting engagement in care at the Nathan Smith Clinic involved gender and insurance differences as well as engagement in HIV/AIDS support services. In order to optimize the longitudinal care initiative and improve clinical health outcomes, an HIV/AIDS multidisciplinary team model should be devised to target these predictors of retention

Mathematics Course Placement Using Holistic Measures: Possibilities for Community College Students.

Background/Context: Most community colleges across the country use a placement test to determine students’ readiness for college-level coursework, yet these tests are admittedly imperfect instruments. Researchers have documented significant problems stemming from overreliance on placement testing, including placement error and misdiagnosis of remediation needs. They have also described significant consequences of misplacement, which can hinder the educational progression and attainment of community college students. Purpose/Objective/Research Question/Focus of Study: We explore possibilities for placing community college students in mathematics courses using a holistic approach that considers measures beyond placement test scores. This includes academic background measures, such as high school GPA and math courses taken, and indicators of noncognitive constructs, such as motivation, time use, and social support. Setting: The study draws upon administrative data from a large urban community college district in California that serves over 100,000 students each semester. The data enable us to link students’ placement testing results, survey data, background information, and transcript records. Research Design: We first use the supplemental survey data gathered during routine placement testing to conduct predictive exercises that identify severe placement errors under existing placement practices. We then move beyond prediction and evaluate student outcomes in two colleges where noncognitive indicators were directly factored into placement algorithms. Findings/Results: Using high school background information and noncognitive indicators to predict success reveals as many as one quarter of students may be misassigned to their math courses by status quo practices. In our subsequent analysis we find that students placed under a holistic approach that considered noncognitive indicators in addition to placement test scores performed no differently from higher scoring peers in the same course. Conclusions/Recommendations: The findings suggest a holistic approach to mathematics course placement may improve placement accuracy and provide access to higher level mathematics courses for community college students without compromising their likelihood of success

The Political Economy of Small Medium Enterprise Development: Characteristics, Productive Value, and Market Constraints in Industrial Manufacturing

This paper highlights the importance of small and medium-sized enterprise (SME) development and introduces the theoretical concept of productive value for qualitative analysis of firms. Vietnam’s industrial development experience is used as a case study. Although the Vietnamese government has channelled rents and business opportunities towards the state sector, the domestic private sector has been crucial to the country’s industrial development. Given this context, this study analyses how Vietnamese SMEs in the private sector generate productive value and overcome market failures that constrain their growth. Research findings demonstrate that most local SMEs in the industrial sectors rely on low pricing strategy to attract buyers. However, those that grow in size frequently go beyond price competition and concentrate on creating new productive value in their production and services. Furthermore, unlike SMEs in developed countries, in Vietnam, firm size is an indicator of productive value and strength. From this perspective, SME development policies in emerging economies must focus on promoting the growth of domestic firms over time

A Link Quality Prediction Metric for Location based Routing Protocols under Shadowing and Fading Effects in Vehicular Ad Hoc Networks

AbstractThe location-based routing protocol has been chosen as one of the efficient routing approaches in vehicular ad hoc networks in terms of low overhead and high scalability. Its critical advantage lies in performing a pathless routing such that a node having a packet forwards it to its neighbor node that provides the shortest physical distance to destination and this process continues until the packet reaches destination. The problem lies in that the link stability of the neighbors varies largely depending on the mobility of vehicles and the environmental factors that incur shadowing and fading effects. In this paper, we propose a new link quality prediction metric associated with location based protocols to improve the selection of next hop, that consider both the link quality assessment based on the transmission success rate and the link quality assessment based on the prediction of the future locations of vehicles. Simulation results are presented to demonstrate the efficiency of the proposed metric

Development of low-grade waste heat recovery using lead-free pyroelectric Ba(Zr,Ti)O3

国立大学法人長岡技術科学大学博士（工学）Articledoctoral thesi

INPUT SHAPING CONTROL TO REDUCE RESIDUAL VIBRATION OF A FLEXIBLE BEAM

In this paper, three control algorithms based on input shaping method are developed to suppress the residual vibration of a flexible beam. The flexible beam is modeled as an under-damped system. Three input shapers, ZV, ZVD, and ZVDD, are used to control the flexible beam. The three control algorithms are implemented by using the Mechatrolink-III motion system. The experiments are performed to verify the effectiveness of the three control algorithms

Support of the eight-foot high temperature tunnel modification project

In order to meet the need for propulsion testing in the high supersonic range from Mach 4 to Mach 7, NASA has undertaken the modification of the Langley Eight Foot High Temperature Tunnel to add alternate Mach number capability and oxygen enrichment to allow the testing of operating engines at these Mach numbers and at true temperature tunnel. The transfer of liquid oxygen (LOX) from a storage vessel to a rocket engine generally requires the use of a pressurizing gas at high pressures. Although nitrogen is preferred, unfortunately, when gaseous nitrogen (GN2) is used as the pressurant to transfer liquid oxygen from a storage tank to the tunnel combustor, it contaminates the liquid oxygen and effects a loss of performance in the engine. The contamination of the LOX by the pressurizing GN2 is described, which may prove to be an important operational constraint. It is desirable to have reliable data concerning the penetration of GN2 into LOX during pressurization and the subsequent of self cleaning after blowdown

Organisational Baseline Study: Overview report for Tra Hat CSV, Vietnam (VN03)

This report covers the Organisational Baseline Study (OBS) for the CCAFS Climate-Smart Village Tra Hat in the South Viet Nam. During October 2014 interviews were conducted with local stakeholders at ten organisations who are working or collaborating with farmers and/or the community in Vinh Loi district, Bac Lieu province. The Tra Hat CSV is located near the coastal area, at tail end of a primary canal of Quan Lo Phung Hiep system (QLPH), the Mekong Delta of Vietnam, it usually causes lack of fresh water in from QLPH in dry season. There are two distinct dry season (December to April) and rainy season (May to November) which typhoon happens seldom in rainy season. Protected by dyke and sluice system of QLPH in Bac Lieu province, Tra Hat has not been affected by saline intrusion for last 15 years. The main farming systems in the village comprise two or three rice crops per year, small livestock as pig, chicken and ducks. Besides, mixed fruit garden and cash crop are often blended in residential area. Ground water and water in ponds is popular in household to provide domestic water, raising fish or garden irrigation and livestock, especially in dry season. The objectives of the OBS study are to: Provide indicators to monitor changes in behaviours and practices of locally relevant organisations that have climate change related activities in Bac Lieu over time Understand the provision of information/services at the local level that informs farmers’ decision making about their livelihood strategies in response to climate change This OBS report also supplements to the quantitative Household Baseline Survey (HBS) and the qualitative Village Baseline Studies (VBS) in Tra Hat CSV and surrounding villages