920 research outputs found

    Morphing Wings Using Macro Fiber Composites

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    Macro Fiber Composites (MFC) are smart materials that have one or more properties that can be altered by an external stimulus such as magnetic and electric fields, temperature and pH, in order to meet specific requirements or conditions. Today, smart materials are used in a variety of applications in the aerospace industry, locomotives, and in the medical field to generate better performance for its devices. The objective of this paper is to describe an experiment on morphing a wing using MFCs. The materials needed to achieve this project are illustrated in the experimental setup of this paper. Additionally, the author expects to be able to morph the wing of the aircraft and compare its acquired data to that of a general aircraft to determine which one has the best performance

    What is the Brillouin Zone of an Anisotropic Photonic Crystal?

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    The concept of the Brillouin zone (BZ) in relation to a photonic crystal fabricated in an optically anisotropic material is explored both experimentally and theoretically. In experiment, we used femtosecond laser pulses to excite THz polaritons and image their propagation in lithium niobate and lithium tantalate photonic crystal (PhC) slabs. We directly measured the dispersion relation inside PhCs and observed that the lowest bandgap expected to form at the BZ boundary forms inside the BZ in the anisotropic lithium niobate PhC. Our analysis shows that in an anisotropic material the BZ - defined as the Wigner-Seitz cell in the reciprocal lattice - is no longer bounded by Bragg planes and thus does not conform to the original definition of the BZ by Brillouin. We construct an alternative Brillouin zone defined by Bragg planes and show its utility in identifying features of the dispersion bands. We show that for an anisotropic 2D PhC without dispersion, the Bragg plane BZ can be constructed by applying the Wigner-Seitz method to a stretched or compressed reciprocal lattice. We also show that in the presence of the dispersion in the underlying material or in a slab waveguide, the Bragg planes are generally represented by curved surfaces rather than planes. The concept of constructing a BZ with Bragg planes should prove useful in understanding the formation of dispersion bands in anisotropic PhCs and in selectively tailoring their optical properties.Comment: 9 pages, 6 figure

    The Information and Communication Technology Infrastructure on University of Mines and Technology Campus and Its Impact on Library e-Resource Accessibility

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    Abstract The University of Mines and Technology (UMaT), Tarkwa, Ghana has a Local Area Network (LAN) infrastructure whose primary purpose is to facilitate research; teaching and learning; and information dissemination. The LAN infrastructure spans a maximum distance of 1.39 square-kilometers with an upload and download speed of 115 Mb/s and interconnects the administration block, faculties, library and halls of residence with high-speed ethernet links operating over a dedicated fiber optic backbone. The LAN infrastructure with connectivity to the internet impact operations in various sections of the University, notably, the University Library. The main purpose of the library is to interact with different information networks to make available e-resource materials to students, academic and non-academic staff. This can only be achieved over a dedicated LAN infrastructure. The introduction of Library Management Systems (Koha), Online Public Access Catalogue (OPAC) and the UMaT Space has improved library services such as document delivery, circulation and borrowing, amongst others. However, there exist a major challenge associated with library e-resources accessibility. This paper sought to investigate the factors hindering library e-resource accessibility for the purposes of improving research. Questionnaire was administered to respondents to solicit primary information while secondary information was obtained from published literature. 537 out of 855 participants responded to the questionnaire administered. 351 (65.36%) represented undergraduate students, 73 (13.60%) represented postgraduate students, 87 (16.20%), 21 (3.91%), 5 (0.93%) represented teaching, non-teaching and library staff respectively. The responses were analysed using simple tables and pie charts. Results from the study showed inadequate access points to enable users access these e-resource materials and lack of knowledge about the existence of these resources. The investigation further revealed the need for the library to embark on an information literacy drive for both students and academic staff. Various ways of improving e-resource accessibility was suggested.   Keywords: Local Area Network, ICT Infrastructure, Online Public Access Catalogue (OPAC), E-Resource

    Engaging local communities in aquatic resources research and activities: a technical manual

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    This document is part of a series of 5 technical manuals produced by the Challenge Program Project CP34 “Improved fisheries productivity and management in tropical reservoirs”. The objective of this technical manual is to relay the field experience of a group of scientists who have worked extensively in small fisheries in sub-Sahara Africa and Asia and lay out a series of simple and pragmatic pointers on how to establish and run initiatives for community catch assessment. The manual relies in particular on practical experience gained implementing Project 34 of the Challenge Programme on Water and Food: Improved Fisheries Productivity and Management in Tropical Reservoirs. (PDF contains 26 pages

    The Emergent Vinifera Wine Industry in North Carolina: A Descriptive Overview

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    The North Carolina (NC) wine industry has grown rapidly over the past decade and is expected to grow even more as the worldwide wine consumption and export of wines rises. In the United States, the wine market has grown by 13.7 percent since 2002 in volume and by more than 15 percent in dollars as wine has progressed from being a beverage of an elite segment of the market to becoming a mainline beverage, taking its place alongside beer and liquor (MKF Research LLC, 2007; Oches, 2009). The Piedmont Triad Region is uniquely positioned to increase its presence in this industry. Of the 80 wineries in NC that are currently open to the public, nearly half are located in the Piedmont Triad Region. However, growing grapes and making wine is a long term commitment to a community, both financially and physically. The MKF Research report states that the capital-intensive nature of the winery and vineyard sectors is often underestimated, with new entrants to the industry at times unprepared for the extended cash requirements. In addition, only a few local institutions are familiar with the unique needs of the winemaking business. In order to address factors that will impede growth in this nascent industry, it is important to identify the state of the industry and obtain management perspectives on the needs and challenges facing their operations. This study provides information that would help gain a better understanding of the business issues and needs related to the wine and grape industry in North Carolina. Data for this study was drawn from a census of 34 wine producers located in the Yadkin, Swan Creek, and the Haw River valley regions of North Carolina. Descriptive statistics using frequencies and means is used to provide a demographic overview of the industry and to identify the factors that wine producers perceive to be important in affecting their profitability. Results from the study shows that most of the wineries share some common traits: they are small, relatively new to the wine and grape industry and grow grapes other than the traditional native Muscadine grape. Primarily, a majority of the wineries are family-based entrepreneurial businesses that have to behave like mini-conglomerates. These findings are consistent with a study conducted by Taplin and Breckenridge (2008).Profitability Constraints, Financial Management, Marketing, Distribution, Agribusiness, Community/Rural/Urban Development, Farm Management,

    Evaluating the level of physical transformation of houses in gated communities in Ghana

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    The upsurge of real estate housing within Accra has resulted in all manner of gated communities springing up across the city scape. These seek to provide housing services to the desperate urban dweller. The quality of their services has however been brought to question due to lack of a proper regulatory body to oversee their work. Recent studies indicate the emergence of physical transformations. This research sought to investigate the conditions and reasons underlying these housing transformations. A case study approach, with a mix of both qualitative and quantitative methods were adopted in determining the conditions of the houses. The relative important index was also used in ranking the various factors that led to these physical transformations. The study revealed that 41% of the houses have undergone transformations with external works, fenetrations, and mechanical and engineering services being most parts affected. Major reasons given for transformation were poor ventilation and lighting. The study recommends amongst others that the government should institute a special regulatory body backed by law with regular assessment from the occupants in order to check the performance of real estate developers.Keywords: Gated community, real estates, physical transformation, housin

    Quasi-Automatic Monitoring System For Turning Operation Using Acoustic Emission Signal Response And Factorial Design Method

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    This work discusses the generation of a quasi monitoring system intended for an operator to change cutting tool during turning operation. The monitoring system uses the effects of turning va riables on acoustic emission signal responses and factorial experimental design approach. In cutting operations, acoustic emission provides useful information concerning the tool wear condition because of the fundamental differences between its source mechanisms in the rubbing friction on the wear land of the single point tool. In this study, effects of cutting speed, feed and tool condition on the acoustic emission signal are investigated using acoustic emission's energy, amplitude, and frequency response and 23 factorial design for turning operation. Cutting tests were performed using high-speed steel under dry conditions. Calculated effects, standard errors at 95% confidence level, and models governing the acoustic emission response to the cutting conditions have been generated from the acoustic emission signal responses. The generated models revealed that acoustic energy response is affected by significant interactions between cutting speed and feed, and insignificant interactions between cutting speed and tool condition, while the acoustic amplitude response is affected by insignificant interactions among cutting speed, feed, and tool condition. These results suggest that acoustic emission's energy and amplitude responses could be used to control the cutting speed and feed during turning operation, thus prolonging the life of the cutting tool.Journal of Science & Technology (Ghana) Vol. 27 (2) 2007: pp. 107-12

    Engaging local communities in aquatic resources research and activities: a technical manual

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    This document is part of a series of 5 technical manuals produced by the Challenge Program Project CP34 ÎImproved fisheries productivity and management in tropical reservoirsö. The objective of this technical manual is to relay the field experience of a group of scientists who have worked extensively in small fisheries in sub-Sahara Africa and Asia and lay out a series of simple and pragmatic pointers on how to establish and run initiatives for community catch assessment. The manual relies in particular on practical experience gained implementing Project 34 of the Challenge Programme on Water and Food: Improved Fisheries Productivity and Management in Tropical Reservoirs.Research, Fishery data

    Estimation of heritability and genetic gain in height growth in Ceiba pentandra

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    Ceiba pentandra (L.) has been selected for plantation establishment in Ghana under the National Forest Plantation Development Programme of Ghana (NFPDP). This has led to a rise in demand for its seedlings for large scale commercial plantation establishments with seed of C. pentandra being collected from the wild and used to raise seedlings to meet the demands of the programme. The primary purpose of most of these plantations is timber with height growth as one of the key economic traits. However, there is relatively inefficient information available on the heritability and genetic gain in height growth in C. pentandra based on which selection and subsequent breeding could be made. This poses a major challenge to the production of new cultivars for the forestry industry of Ghana. The current study looked at the estimation of narrow sense heritability (h2) and genetic gain in height growth in C. pentandra using 37 accessions from Ghana. Narrow sense heritability was 0.56 and genetic gain in height ranged from -52.82 to 37.30 cm/yr. Twenty-two (22) accessions (59.46%) had mean height increment above the overall mean performance and were recommended for conservation as seed trees. The results were discussed in relation with the conservation of C. pentandra genetic resources and the potential of accessions for high genetic gains.Key words: Ceiba pentandra, narrow sense heritability, genetic gain, height growth, stem dieback disease

    Determination of Trace Metals Quality of Sources of Drinking Water in Some Selected Communities in the Akuapem South District of the Eastern Region, Ghana

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    The study was undertaken in three communities namely Adamrobe, Aburi and Pokrom-Nsaba, all located in the Akuapim South District of the Eastern Region. These communities depend on streams, wells, and springs for their drinking water requirements. The objective of the study was to assess the trace metals quality of the drinking water sources used by the communities. Water samples from these sources (streams, wells, and springs) were analyzed over a period of twelve months for various water quality parameters including the following trace metals: lead (Pb), cadmium (Cd), zinc (Zn), & arsenic (As), following standard methods designed in APHA, AWWA, and WEF. The results of the study revealed that, most of the mean levels of trace metals registered from the water samples were below the World Health Organization (WHO) and Ghana Water Company Limited (GWCL) recommended critical limits for drinking water standards. The low level of trace metals recorded in the water samples was due to the absence of industrial and mining activities in these communities and their environs. The high level of lead registered in ABSP was as a result of the low pH discovered in the water sample for that station. It is therefore recommended that further study be conducted to track the long term health effects of the trace metals in the drinking water sources used by the study communities. Keywords: Trace Metals Quality, Sources of Drinking Water, Selected Communities, Akuapem South District, Eastern Region, Ghana
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