132 research outputs found
Variable area radial turbine fabrication and test program
A variable area radial turbine with a moveable nozzle sidewall was experimentally evaluated. The turbine was designed for an advanced variable capacity gas turbine rotorcraft engine. The turbine has a mass flow rate of 2.27 kg/sec (5.0 lbs/sec), and a rotor inlet temperature of 1477K (2200 F). Testing was conducted at a reduced inlet temperature, but the aerodynamic parameters and Reynolds numbers were duplicated. Overall performance was obtained for a range of nozzle areas from 50% to 100% of the maximum area. The test program determined the effect on performance of: (1) Moving the hub or shroud sidewall; (2) Sidewall-vane clearance leakage; (3) Vaneless space geometry change; and (4) Nozzle cooling flows. Data were obtained for a range of pressure ratios and speeds and are presented in a number of performance maps
Cooled variable nozzle radial turbine for rotor craft applications
An advanced, small 2.27 kb/sec (5 lbs/sec), high temperature, variable area radial turbine was studied for a rotor craft application. Variable capacity cycles including single-shaft and free-turbine engine configurations were analyzed to define an optimum engine design configuration. Parametric optimizations were made on cooled and uncooled rotor configurations. A detailed structural and heat transfer analysis was conducted to provide a 4000-hour life HP turbine with material properties of the 1988 time frame. A pivoted vane and a moveable sidewall geometry were analyzed. Cooling and variable geometry penalties were included in the cycle analysis. A variable geometry free-turbine engine configuration with a design 1477K (2200 F) inlet temperature and a compressor pressure ratio of 16:1 was selected. An uncooled HP radial turbine rotor with a moveable sidewall nozzle showed the highest performance potential for a time weighted duty cycle
Can Reproductive Health Voucher Programs Improve Quality of Postnatal Care? A Quasi-Experimental Evaluation of Kenya’s Safe Motherhood Voucher Scheme
This study tests the group-level causal relationship between the expansion of Kenya’s Safe Motherhood voucher program and changes in quality of postnatal care (PNC) provided at voucher-contracted facilities. We compare facilities accredited since program inception in 2006 (phase I) and facilities accredited since 2010-2011 (phase II) relative to comparable non-voucher facilities. PNC quality is assessed using observed clinical content processes, as well as client-reported outcome measures. Two-tailed unpaired t-tests are used to identify differences in mean process quality scores and client-reported outcome measures, comparing changes between intervention and comparison groups at the 2010 and 2012 data collection periods. Difference-in-differences analysis is used to estimate the reproductive health (RH) voucher program’s causal effect on quality of care by exploiting group-level differences between voucher-accredited and non-accredited facilities in 2010 and 2012. Participation in the voucher scheme since 2006 significantly improves overall quality of postnatal care by 39% (p=0.02), where quality is defined as the observable processes or components of service provision that occur during a PNC consultation. Program participation since phase I is estimated to improve the quality of observed maternal postnatal care by 86% (p=0.02), with the largest quality improvements in counselling on family planning methods (IRR 5.0; p=0.01) and return to fertility (IRR 2.6; p=0.01). Despite improvements in maternal aspects of PNC, we find a high proportion of mothers who seek PNC are not being checked by any provider after delivery. Additional strategies will be necessary to standardize provision of packaged postnatal interventions to both mother and new-born. This study addresses an important gap in the existing RH literature by using a strong evaluation design to assess RH voucher program effectiveness on quality improvement
Time for global scale-up, not randomized trials, of uterine balloon tamponade for postpartum hemorrhage.
Maternal death is the greatest health disparity globally, with postpartum hemorrhage the most common cause. As senior leaders in obstetrics and maternal health from Bolivia, Canada, Colombia, Côte d'Ivoire, Honduras, India, Kenya, Nepal, Niger, Norway, Peru, Tanzania, the UK, the USA, and Zambia, we are deeply disturbed by recent calls for randomized controlled trials (RCTs) of uterine balloon tamponade (UBT) in women with uncontrolled postpartum hemorrhage (PPH). Our collective experience, in combination with mounting evidence, unequivocally supports the effectiveness of commercial and condom UBTs in averting death and disability from PPH associated with atonic uterus. We believe it would be highly unethical to embark on an RCT of UBT, now or in the future, unless compared with a proven equivalent intervention. This article is protected by copyright. All rights reserved
A strategic assessment of cervical cancer prevention and treatment services in 3 districts of Uttar Pradesh, India
BACKGROUND: Despite being a preventable disease, cervical cancer claims the lives of almost half a million women worldwide each year. India bears one-fifth of the global burden of the disease, with approximately 130,000 new cases a year. In an effort to assess the need and potential for improving the quality of cervical cancer prevention and treatment services in Uttar Pradesh, a strategic assessment was conducted in three of the state's districts: Agra, Lucknow, and Saharanpur. METHODS: Using an adaptation of stage one of the World Health Organization's Strategic Approach to Improving Reproductive Health Policies and Programmes, an assessment of the quality of cervical cancer services was carried out by a multidisciplinary team of stakeholders. The assessment included a review of the available literature, observations of services, collection of hospital statistics and the conduct of qualitative research (in-depth interviews and focus group discussions) to assess the perspectives of women, providers, policy makers and community members. RESULTS: There were gaps in provider knowledge and practices, potentially attributable to limited provider training and professional development opportunities. In the absence of a state policy on cervical cancer, screening of asymptomatic women was practically absent, except in the military sector. Cytology-based cancer screening tests (i.e. pap smears) were often used to help diagnose women with symptoms of reproductive tract infections but not routinely screen asymptomatic women. Access to appropriate treatment of precancerous lesions was limited and often inappropriately managed by hysterectomy in many urban centers. Cancer treatment facilities were well equipped but mostly inaccessible for women in need. Finally, policy makers, community members and clients were mostly unaware about cervical cancer and its preventable nature, although with information, expressed a strong interest in having services available to women in their communities. CONCLUSION: To address gaps in services and unmet needs, state policies and integrated interventions have the potential to improve the quality of services for prevention of cervical cancer in Uttar Pradesh
Price Level Convergence, Purchasing Power Parity and Multiple Structural Breaks: An Application to US Cities
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