3,832 research outputs found
Preparation and characterisation of thin film CdS/CdTe solar cells produced by close space sublimation.
Determination of design-related properties of selected Irish potatoes varieties
The aim of this study was to determine some design-related properties of Irish potatoes commonly grown in Nigeria that may be useful in designing, handling and processing equipment of the product. Two varieties were selected: Nicola and Diamant. The measured properties were length, width, thickness, bulk density, solid density and angle of repose. Other parameters were arithmetic mean, geometric mean, surface area, volume, porosity and kernel weight. The mean length, width and thickness obtained for Nicola variety were 66.5, 37.3 and 32.4 mm respectively; while 57.4, 35.2, and 31.7 mm were obtained for Diamant, respectively. The mean angle of repose of Nicola and Diamant varieties were 27.20 and 26.40°, respectively. Mean roundness of Nicola and Diamant varieties were also obtained as 0.6 and 0.7 respectively. The mean surface area and volume of Nicola variety was determined to be 58.55 cm2 and 42.61 cm³ while that of Diamant variety was 50.31 cm² and 34.08 cm³, respectively. Moisture contents of Nicola and Diamant varieties used were obtained as 76.3 and 85.9%, respectively. Mean hardness of Nicola and Diamant varieties was 1.52 and 1.7 HV, respectively; indicating that Diamant is a harder variety than Nicola. These properties may be useful and serve as a guide on major engineering design of handling and processing equipment
Integration of the ASTER thermal infra-red bands imageries with geological map of Jabal Al Hasir area, Asir Terrane, the Arabian Shield
AbstractThermal infra-red bands of Advanced Spaceborne Thermal Emission and Radiometer (ASTER) have been used to investigate rocks, including white quartz veins, of Jabal Al Hasir area of the Asir Terrane, southwestern part of the Arabian Shield. The obtained data were processed using radiometric and geometric corrections. The processed data were then enhanced into false color images by Thermal Infra Red band ratioing. These composite images clearly differentiate between the light color felsic granite rocks and the dark color mafic gabbroic rocks. These images also differentiate quartz veins from wadi deposits, although, both of them appear very similar in light color and light grayscale tone. Results of the band ratioing have also been compared with the geological map of the study area, and were found in agreement. Keeping in view the obtained resolution, the band ratioing images have been found more informative and useful than the regular color composite images. Based on these observations, it can be claimed that the ASTER sensor is more powerful in terms of geological applications. Due to its success in the study area, the use of this sensor could also be extended to other complicated areas in the Arabian Shield and beyond
IR optical fiber-based noncontact pyrometer for drop tube instrumentation
The design of a two color pyrometer with infrared optical fiber bundles for collection of the infrared radiation is described. The pyrometer design is engineered to facilitate its use for measurement of the temperature of small, falling samples in a microgravity materials processing experiment using a 100 meter long drop tube. Because the samples are small and move rapidly through the field of view of the pyrometer, the optical power budget of the detection system is severly limited. Strategies for overcoming this limitation are discussed
Mediating Cognitive Transformation with VR 3D Sketching during Conceptual Architectural Design Process
Communications for information synchronization during the conceptual design phase require designers to employ more intuitive digital design tools. This paper presents findings of a feasibility study for using VR 3D sketching interface in order to replace current non-intuitive CAD tools. We used a sequential mixed method research methodology including a qualitative case study and a cognitive-based quantitative protocol analysis experiment. Foremost, the case study research was conducted in order to understand how novice designers make intuitive decisions. The case study documented the failure of conventional sketching methods in articulating complicated design ideas and shortcomings of current CAD tools in intuitive ideation. The case study’s findings then became the theoretical foundations for testing the feasibility of using VR 3D sketching interface during design. The latter phase of study evaluated the designers’ spatial cognition and collaboration at six different levels: “physical-actions”, “perceptualac ons”, “functional-actions”, “conceptual-actions”, “cognitive synchronizations”, and “gestures”. The results and confirmed hypotheses showed that the utilized tangible 3D sketching interface improved novice designers’ cognitive and collaborative design activities. In summary this paper presents the influences of current external representation tools on designers’ cognition and collaboration as well as providing the necessary theoretical foundations for implementing VR 3D sketching interface. It contributes towards transforming conceptual architectural design phase from analogue to digital by proposing a new VR design interface. The paper proposes this transformation to fill in the existing gap between analogue conceptual architectural design process and remaining digital engineering parts of building design process hence expediting digital design process
On the matched pairs sign test using bivariate ranked set sampling: an application to environmental issues
The matched pairs sign test using bivariate ranked set sampling (BVRSS) is introduced and investigated. We show that this test is asymptotically more efficient than its counterpart sign test based on a bivariate simple random sample (BVSRS). The asymptotic null distribution and the efficiency of the test are derived. The Pitman asymptotic relative efficiency is used to compare the asymptotic performance of the matched pairs sign test using BVRSS versus using BVSRS. For small sample sizes, the bootstrap method is used to estimate P-values. Numerical comparisons are used to gain insight about the efficiency of the BVRSS sign test compared to the BVSRS sign test. Our numerical and theoretical results indicate that using BVRSS for the matched pairs sign test is substantially more efficient than using BVSRS. Illustration using palm trees data from sultanate of Oman is provided.Key words: Bootstrap method, bivariate ranked set sample, power of the test, P-value of the test, Pitman’s relative efficiency, sign test
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