7,942 research outputs found

    Further laboratory studies of the roughness and suspended load of alluvial streams

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    A laboratory study was made to determine the variation with depth and velocity of the hydraulic and sediment transport characteristics of a constant-discharge flow. Eight experimental runs were performed in a 60-foot long, 33.5-inch wide recirculating laboratory flume. The unit discharge for all runs was 0.50 cfs per ft. and the velocity was varied from 0.91 to 2.21 fps, corresponding to a change in depth from 0.550 to 0.228 ft. The bed sand used for these experiments had a geometric mean sieve diameter of 0.142 mm and a geometric standard deviation of 1.38. As the velocity was increased, the bed form changed from a dune-covered configuration to a flat bed, with sand waves occurring at intermediate velocities. It was found that for the unit discharge and bed sand used in this investigation, two different velocities and sediment transport rates are possible for a given slope, or a given bed shear velocity; however, this multiplicity is possible only in the range of slope and shear velocity where major changes in the bed configuration occur since it is a result of large variations in the bed roughness. Therefore the slope or shear velocity cannot logically be used as an independent variable since neither of these quantities uniquely determines the velocity or transport rate. However, if the velocity is used as the independent variable for a constant-discharge flow, the slope, shear velocity, and friction factor are all uniquely determined. The sediment transport rate was found to be a single-valued, uniformly increasing function of velocity, and it can therefore be used in place of the velocity as the independent variable. A comparison of data from this investigation with data from previous investigations which used the same sand showed that even a small decrease in the amount of fine material in the bed sand can have a significant effect on the transport rate. However, even relatively large changes in the standard deviation of the bed material have a small effect on the friction factor

    Balancing Public & Private Partnerships for Future Human Spaceflight

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    Privatization is key to America's current and future interests in Space and is consistent with the 2010 Title 51 "National Aeronautics and Space Act" which states "COMMERCIAL USE OF SPACE. - Congress declares that the general welfare of the United States requires that the Administration seek and encourage, to the maximum extent possible, the fullest commercial use of space." With this thought in mind, this paper discusses several key considerations when entering into a Human Spaceflight Public/Private partnership, with particular attention to the engineering team engagement. NASA's historically develops technology and capability in areas that are not commercially profitable but can enable future commercial opportunities. By leveraging the experiences and lessons learned from the past, we can improve our opportunities for success in the future. We have made great strides in these areas, but there is significant room for improvement. This paper intends to highlight many of the thoughts and considerations, which are necessary when developing a public/private partnership for "Human Spaceflight". Although this paper is being developed with an emphasis on "Human Spaceflight", many of the thoughts may have applicability to un-crewed missions. This paper does not attempt to define specific lines between government and private entities, since those lines vary based on many factors such as allocation of roles, responsibilities and accountabilities between participants and risk tolerance for both safety of flight and mission success

    Towards universal health coverage: Exploring the determinants of household enrolment into National Health Insurance in the Kassena Nankana District, Ghana

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    This study investigates the determinants of household participation in National Health Insurance Scheme (NHIS) in the Kassena-Nankana District in Ghana. In order to achieve this purpose, a cross-sectional survey was used to collect data from 417 randomly selected household heads. The results established that the NHIS is making incremental progress towards achieving universal health coverage because majority (67%) of the sampled population was enrolled in the NHIS. However, further analysis of the data highlighted both the challenge of achieving equity of participation in health insurance and the yawning financial barriers to accessing health care for poor households and those employed in the informal sector. For example, majority (77%) of uninsured households indicated that they were not enrolled in the NHIS because they could not afford the cost of insurance premiums. The research findings showed that income, socio-economic status (SES), formal employment, educational status, and gender amongst others, significantly determine household enrolment in health insurance. In order to increase the enrolment of the poor in the NHIS, and of achieving universal health coverage, the authors recommend that the government considers using payroll deductions to finance the health care needs of all formal sector employees while financing the health care of the rest of the population using tax revenues. It is also recommeded that the NHIS considers making the payment of insurance premium flexible, such as allowing housholds to pay in installments or in kind.International Bibliography of Social Science

    Making programme learning outcomes explicit for students of process and chemical engineering

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    There is a global shift from solely content-driven teaching to learning outcomes driven engineering education which underpins much of the educational reform. In engineering education, degree programme learning outcomes are more commonplace as more and more professional accrediting bodies require fulfilment or compliance with prescribed learning outcomes. However, the students may not be presented with these learning outcomes as they are often “hidden” in application for accreditation documentation and not divulged to the students. This is the context of this thesis study. Undergraduate students (2006-2008) taking the BE degree programme in Process & Chemical Engineering at UCC were first surveyed to assess their level of knowledge of the learning outcomes concept and of the degree programme learning outcomes. The contents of two application documents for accreditation documents submitted to professional accreditation bodies along with Institution guidelines were reviewed to formulate the degree programme learning outcomes and these were presented to the students. These students were then surveyed after the presentation. The results of the questionnaire demonstrated a major improvement in the knowledge of the learning outcomes concept and the degree programme learning outcomes amongst the students. It also showed that the students found the session to be beneficial

    Hogging-down corn---A successful practice

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    “Hogging-down” of corn is a practical and efficient method of gathering the crop and feeding the hogs. Farmers who have tried it are almost unanimously agreed that the method is economical and successful. The most enthusiastic “hogging-down” men are those who have followed the method longest. The animal husbandry section of the Iowa Agricultural Experiment Station has in practical tests convincingly justified this faith of the practical men

    Book Reviews

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    Ensnaring the Elusive Eodermdrome

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    We wish to introduce the recreational aspects of the eodermdrome, which is a recently formulated concept dealing with the structure of language units such as letters and words. Although this concept may eventually lead to a numerical way to compare the structural differences between languages and to trace structural development in a single language, the majority of individuals who learn about eodermdromes evince less interest in their potential scholarly ramifications than in the delightful task of creating them
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