982 research outputs found
Prospects for Sustainable Housing in Northern Ghana with the use of Local Walling Materials
In 2006 the World Bank described Ghana as a third World country having only 1 out of 3 persons sheltered. Suggestions were made that locally available materials instead of imported materials be used in building so as to cut down on costs and subsequently increase supply of housing units. In response, this study, focusing on Northern Ghana, conducted a cross-sectional survey of seventy respondents with a structured questionnaire to identify the major locally available walling material in use as well as find benefits and challenges associated with it. Unburnt earth bricks were identified as the major locally available walling material in use in Northern Ghana. Benefits found to be promoting its use were the thermal comforts it provided, the manner housing became cheaper, the cultural heritage that it promoted and the fact that only simple tools and methods were employed in its use as a building component. Challenges associated with the unburnt earth brick wall were, lack of recognition by Statutory Authorities, lack of strength and durability, challenges in satisfying new needs in building forms and functions, invasion by termites and rodents as well as its weakness in withstanding vagaries of the weather. Recommendations were made to overcome challenges associated with the use of the material with the aim of enhancing prospects of adopting it for sustainable housing. The study concluded that the Locally available walling material in the form of unburnt earth brick had a huge potential for sustainable housing in Northern Ghana if only government would, through competitive tenders among building technologists utilise existing research findings to get the material stabilised to the required strengths and characteristics so as to pave the way for its recognition by statutory authorities and subsequent packaging for commercial use in the building industry. This paper contributes to the body of knowledge in the areas of Environment, Architecture, Construction Management and Building Materials in a middle income country setting. Keywords: Local, Walling materials, Housing, Northern Ghana, Sustainability, Middle income countr
Designing citizen science tools for learning: lessons learnt from the iterative development of nQuire
This paper reports on a 4-year research and development case study about the design of citizen science tools for inquiry learning. It details the process of iterative pedagogy-led design and evaluation of the nQuire toolkit, a set of web-based and mobile tools scaffolding the creation of online citizen science investigations. The design involved an expert review of inquiry learning and citizen science, combined with user experience studies involving more than 200 users. These have informed a concept that we have termed ‘citizen inquiry’, which engages members of the public alongside scientists in setting up, running, managing or contributing to citizen science projects with a main aim of learning about the scientific method through doing science by interaction with others. A design-based research (DBR) methodology was adopted for the iterative design and evaluation of citizen science tools. DBR was focused on the refinement of a central concept, ‘citizen inquiry’, by exploring how it can be instantiated in educational technologies and interventions. The empirical evaluation and iteration of technologies involved three design experiments with end users, user interviews, and insights from pedagogy and user experience experts. Evidence from the iterative development of nQuire led to the production of a set of interaction design principles that aim to guide the development of online, learning-centred, citizen science projects. Eight design guidelines are proposed: users as producers of knowledge, topics before tools, mobile affordances, scaffolds to the process of scientific inquiry, learning by doing as key message, being part of a community as key message, every visit brings a reward, and value users and their time
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Microstructural understanding and critical current optimization of advanced high field superconductors
It is of great importance to improve critical current density, J[sub c] in A15 superconductors for high field magnet applications. Most current work to improve J[sub c] in A15 wires concentrates on increasing the overall J[sub c] by increasing the fraction of superconducting phase in the wire, by improving the uniformity of the superconductor cross section along the length of the wire and by adjusting the strainstate of the A15 layer. The goal of the A15 work in this group was to investigate the intrinsic J[sub c] of the A15 layer itself. To do this, a better understanding of factors controlling the intrinsic J[sub c]of the Nb[sub 3]Sn was pursued
Effects of different ageing methods on colour, yield, oxidation and sensory qualities of Australian beef loins consumed in Australia and Japan
This study investigated the effect of three ageing methods (dry, wet and stepwise wet-then-dry) and ageing time on pH, colour, yield, lipid and protein oxidation and eating quality of beef loins using Meat Standards Australia (MSA) sensory protocol with 900 and 540 consumers in Australia and Japan, respectively. Australian beef loins (Longissimus thoracis et lumborum) at four days post mortem were subjected to wet ageing (boneless; for 7, 21, 35 or 56 days), dry ageing (bone-in; for 35 or 56 days) or a wet-then-dry ageing method (bone-in; 21 days wet ageing followed by 35 days dry ageing). The pH was higher in dry aged than wet aged beef loins (P < .001). Instrumental measurement of surface colour of trimmed dry and wet aged steaks showed significant differences in a*, b* and hue angle. Weight loss was higher in dry aged primals (P < .001), however, total water content was similar among the two ageing methods (P = .934). Retail yield did not differ between 35 and 56 days dry aged primals. Lipid (TBARS) and protein (total carbonyl content) oxidation between the dry and wet aged samples differed depending on the ageing time. When comparing the wet-then-dry and 56 days dry aged samples, only pH and retail yield differed. Australian and Japanese consumers rated dry aged steaks significantly higher (P < .001) than the wet aged counterparts for tenderness, juiciness, flavour, overall liking and weighted palatability scores. The wet-then-dry steaks were also rated higher than the 56 days wet aged steaks for flavour, overall liking and palatability within the Japanese sensory panels. The Japanese consumers also consistently rated all MSA sensory attributes lower (P < .001) than the Australian consumers. The results from this study show dry ageing provides a value adding opportunity for the meat industry in both domestic and export markets
Core pinning by intragranular nanoprecipitates in polycrystalline MgCNi_3
The nanostructure and magnetic properties of polycrystalline MgCNi_3 were
studied by x-ray diffraction, electron microscopy, and vibrating sample
magnetometry. While the bulk flux-pinning force curve F_p(H) indicates the
expected grain-boundary pinning mechanism just below T_c = 7.2 K, a systematic
change to pinning by a nanometer-scale distribution of core pinning sites is
indicated by a shift of F_p(H) with decreasing temperature. The lack of scaling
of F_p(H) suggests the presence of 10 to 20% of nonsuperconducting regions
inside the grains, which are smaller than the diameter of fluxon cores 2xi at
high temperature and become effective with decreasing temperature when xi(T)
approaches the nanostructural scale. Transmission electron microscopy revealed
cubic and graphite nanoprecipitates with 2 to 5 nm size, consistent with the
above hypothesis since xi(0) = 6 nm. High critical current densities, more than
10^6 A/cm^2 at 1 T and 4.2 K, were obtained for grain colonies separated by
carbon. Dirty-limit behavior seen in previous studies may be tied to electron
scattering by the precipitates, indicating the possibility that strong core
pinning might be combined with a technologically useful upper critical field if
versions of MgCNi_3 with higher T_c can be found.Comment: 5 pages, 6 figures, submitted to PR
The development of a business intelligence web application to support the decision-making process regarding absenteeism in the workplace
Nowadays, one of the biggest concerns of industries all over the world is situations regarding absenteeism, since it has a great impact on the productivity and economy of companies, as well as on the health of their employees. The major causes of absenteeism appear to be work accidents and sickness leaves, which lead to the attempt by companies of understanding how the workload is related to the health of their collaborators and, consequently, to absenteeism. Thus, this paper proposes the design and development of a Web Application based on Business Intelligence indicators in order to help the health and human resources professionals of a Portuguese company analyse the relation between absenteeism and the health and lifestyle of employees, with the intention of concluding whether the work executed on the company is harming workers’ health. Furthermore, it is intended to discover the principal motives for the numerous and more frequent absences in this company, so that it is possible to decrease the absenteeism rate and, hence, improve the decision-making process. This platform will also provide higher quality healthcare and the possibility to find patterns in the absence of collaborators, as well as reduce time-waste and errors.This work has been supported by FCT –Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/201
Effect of Cutting Parameters on Surface Finish when Turning Nitronic 33 Steel alloy
Nitronic 33 steel alloys are metallic alloys that exhibit characteristics such as high strength-to-weight ratio, outstanding
corrosion and erosion resistant properties, and the ability to withstand cryogenic conditions and elevated temperatures. These
characteristics of Nitronic 33 steel alloys make it popular in the fabrication of chemical processing, pollution control, aerospace equipment,
and for steam and autoclave applications. Nitronic 33 steel alloy is classified as difficult-to-cut materials because of its high nitrogen
content and the capability to form martensite as a result of high temperatures generated during mechanical machining and other
subtractive manufacturing processes. This resulted in increased capacity and tooling cost during manufacturing. Therefore, there is the
need to evaluate the optimum parameters when machining this alloy for sustainable and resource efficient machining. In this work, tool life,
tool wear, surface roughness, cutting forces and power demand when turning Nitronic 33 steel alloy under different cutting environment
were investigated. The result presented an optimum turning conditions at which Nitronic 33 steel alloy can be manufactured with minimum
tool wear and surface integrity. The research outcome also addresses some of the problems encountered during the high speed machining
of Nitronic 33 steel alloy that could influence manufacturing cost reduction. This work will also aid the general understanding of Nitronic 33
steel alloy with respect to sustainable and resource efficient machining
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