670 research outputs found

    Initial results from the NASA-Lewis wave rotor experiment

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    Wave rotors may play a role as topping cycles for jet engines, since by their use, the combustion temperature can be raised without increasing the turbine inlet temperature. In order to design a wave rotor for this, or any other application, knowledge of the loss mechanisms is required, and also how the design parameters affect those losses. At NASA LeRC, a 3-port wave rotor experiment operating on the flow-divider cycle, has been started with the objective of determining the losses. The experimental scheme is a three factor Box-Behnken design, with passage opening time, friction factor, and leakage gap as the factors. Variation of these factors is provided by using two rotors, of different length, two different passage widths for each rotor, and adjustable leakage gap. In the experiment, pressure transducers are mounted on the rotor, and give pressure traces as a function of rotational angle at the entrance and exit of a rotor passage. In addition, pitot rakes monitor the stagnation pressures for each port, and orifice meters measure the mass flows. The results show that leakage losses are very significant in the present experiment, but can be reduced considerably by decreasing the rotor to wall clearance spacing

    Feasibility of Expanding the Use of Steel Slag as a Concrete Pavement Aggregate

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    Sustainability has become an important aspect of developed countries throughout the world. Sustainability is the ability to use byproducts and or waste materials from industry and recycle these materials in such a way that the application of the materials provides a beneficial use in the manufacturing or construction sector. As the United States and the rest of the world continue to grow, so too does the demand on the limited natural resources throughout the world. It is this demand on the resources that has brought the idea of sustainability to the forefront of research and design.The transportation industry continues to incorporate sustainability into its projects. The industry is constantly trying new and innovative ways to recycle materials that would otherwise be sent to a landfill. Slag, a byproduct from the production of steel, is one of these materials. The transportation sector has used slags as aggregates for subbase and base layers in roads. Some slags, like blast furnace slag, have been used in portland concrete cement (PCC) applications as well. The focus of this research is to investigate the feasibility of using steel slag as an aggregate for use in portland concrete cement.An important aspect of this research was to complete a comprehensive review of other research that has been conducted on the use of steel slag as an aggregate. The literature reviewed included of laboratory studies that focused on the physical, mechanical, chemical, and expansive characteristics of the steel slag. The research on the use of steel slag was gathered from 16 different countries, which include the United States, Spain, Japan, China, Germany, Finland, and Saudi Arabia. Some of these studies have found that properly treated slag may be non-expansive and used in PCC. The possible expansion of the steel slag is the most important characteristic. The expansion of the steel slag aggregate can have detrimental effects on a pavement. This research investigated some of the treatment processes that are being used to alter t

    Feasibility of Expanding the Use of Steel Slag as a Concrete Pavement Aggregate

    Get PDF
    Sustainability has become an important aspect of developed countries throughout the world. Sustainability is the ability to use byproducts and or waste materials from industry and recycle these materials in such a way that the application of the materials provides a beneficial use in the manufacturing or construction sector. As the United States and the rest of the world continue to grow, so too does the demand on the limited natural resources throughout the world. It is this demand on the resources that has brought the idea of sustainability to the forefront of research and design.The transportation industry continues to incorporate sustainability into its projects. The industry is constantly trying new and innovative ways to recycle materials that would otherwise be sent to a landfill. Slag, a byproduct from the production of steel, is one of these materials. The transportation sector has used slags as aggregates for subbase and base layers in roads. Some slags, like blast furnace slag, have been used in portland concrete cement (PCC) applications as well. The focus of this research is to investigate the feasibility of using steel slag as an aggregate for use in portland concrete cement.An important aspect of this research was to complete a comprehensive review of other research that has been conducted on the use of steel slag as an aggregate. The literature reviewed included of laboratory studies that focused on the physical, mechanical, chemical, and expansive characteristics of the steel slag. The research on the use of steel slag was gathered from 16 different countries, which include the United States, Spain, Japan, China, Germany, Finland, and Saudi Arabia. Some of these studies have found that properly treated slag may be non-expansive and used in PCC. The possible expansion of the steel slag is the most important characteristic. The expansion of the steel slag aggregate can have detrimental effects on a pavement. This research investigated some of the treatment processes that are being used to alter t

    Apologies for forced adoption practices: Implications for contemporary intercountry adoption

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    2012 marked historic events in the practice of adoption in Australia. Government focus was on the formulation of apologies to those people affected by past forced adoption practices. A critical reflection on these and other Australian apologies, highlight assumptions that differentiate past domestic adoption practices from past and contemporary practice in intercountry adoption. The importance of social work, founded in the values of social justice and human rights, to ensuring the same practice standards apply to all people who give birth to children regardless of where they live is highlighted. Expanding knowledge on intercountry adoption indicates that Australia should prepare for another apology

    Heat transfer results and operational characteristics of the NASA Lewis Research Center Hot Section Cascade Test Facility

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    The NASA Lewis Research Center gas turbine hot section test facility has been developed to provide a real-engine environment with well known boundary conditions for the aerothermal performance evaluation/verification of computer design codes. The initial aerothermal research data obtained are presented and the operational characteristics of the facility are discussed. This facility is capable of testing at temperatures and pressures up to 1600 K and 18 atm which corresponds to a vane exit Reynolds number range of 0.5x10(6) to 2.5x10(6) based on vane chord. The component cooling air temperature can be independently modulated between 330 and 700 K providing gas-to-coolant temperature ratios similar to current engine application. Research instrumentation of the test components provide conventional pressure and temperature measurements as well as metal temperatures measured by IR-photography. The primary data acquisition mode is steady state through a 704 channel multiplexer/digitizer. The test facility was configured as an annular cascade of full coverage filmcooled vanes for the initial series of research tests

    Intercountry adoption: Privilege, rights and social justice

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    Intercountry adoption tends to be understood in parts - the individual child, the needs of adoptive parents, the legality of its processes, and perceived red tape. Mostly, however, the focus is the facilitation of placing a child with a prospective adoptive family, and the elimination of perceived barriers between the adoptive parents and the desired child. By failing fully to consider the whole picture concerning intercountry adoption, important issues are obscured and disempowered people remain disempowered. Resources are consequently directed towards specific, enabling aspects of intercountry adoption, a need constructed by influential voices particularly where the market approach dominates (Fronek, 2009). In that process, other considerations such as the moral or material circumstances that lead to intercountry adoption and the disempowered first parents, families and communities tend to be ignored in public commentary in the media and in adoptive parent group blogs and chatrooms

    ‘This neo- natal ménage à trois’: British media framing of transnational surrogacy

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    Background: Media framing can influence people’s perceptions of social changes in family building, and has the potential to influence their future actions. Objectives: to analyse the type of framing and construction used in British news print of transnational commercial surrogacy. Methods: UK newspapers were searched using the search engine Lexis-Nexis. One hundred ninety seven articles were analysed. Content analysis was undertaken to identify the use of gain, loss, neutral, alarm and vulnerability frames, as well as type of construction (i.e. ethical, social, legal, financial and medical). Four researchers independently analysed articles using a coding strategy. Results: Differences between serious (mainly legal, financial), middle market (legal) and tabloid (social, financial) newspapers were found. There were three main foci; buying babies - affordable only to those wealthy enough to pay for it; the legal complications of transnational surrogacy - reporting a sense of the legal system lagging behind this practice; and gay families - repeatedly questioning their suitability as parents - demonstrating a prevailing heterosexual stereotype about reproduction and parenting. Conclusions: Stereotyping was prevalent and the welfare of children and medical aspects of transnational surrogacy were minimally addressed, indicating the media selectively influences its readership

    ‘This neo- natal ménage à trois’: British media framing of transnational surrogacy

    Get PDF
    Background: Media framing can influence people’s perceptions of social changes in family building, and has the potential to influence their future actions. Objectives: to analyse the type of framing and construction used in British news print of transnational commercial surrogacy. Methods: UK newspapers were searched using the search engine Lexis-Nexis. One hundred ninety seven articles were analysed. Content analysis was undertaken to identify the use of gain, loss, neutral, alarm and vulnerability frames, as well as type of construction (i.e. ethical, social, legal, financial and medical). Four researchers independently analysed articles using a coding strategy. Results: Differences between serious (mainly legal, financial), middle market (legal) and tabloid (social, financial) newspapers were found. There were three main foci; buying babies - affordable only to those wealthy enough to pay for it; the legal complications of transnational surrogacy - reporting a sense of the legal system lagging behind this practice; and gay families - repeatedly questioning their suitability as parents - demonstrating a prevailing heterosexual stereotype about reproduction and parenting. Conclusions: Stereotyping was prevalent and the welfare of children and medical aspects of transnational surrogacy were minimally addressed, indicating the media selectively influences its readership

    History repeating..disaster-related intercountry adoption and psychosocial care of children

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    Disasters are prevalent with devastating effects on vulnerable populations that include the elderly, disabled, women and children. Historical responses to vulnerable children and families post-disaster raise questions concerning further harms to children rescued by adoption in the aftermath of devastation. This article offers critical and historical perspectives on child removal for adoption in the context of disaster and the psychosocial care of children affected by disaster. It brings into question whether removal, especially permanent removal for adoption, is in their interests. This article concludes that efforts are needed by the international community to ensure that past abuses do not recu
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