The aim of this study was to investigate the effects of short-term repeated passes tillage operations on bulk density, soil penetration resistance, soil porosity and the moisture of a clay loam soil of Malaysia. A field experiment for three seasons was conducted at Sungai Burong Tanjung Karang Kuala Selangor, Malaysia to study treatments consisting of (I) no-tillage NT (II) first tillage FT (III) second tillage (ST), (IV) third tillage (TT) operations. The soil bulk density, soil penetrometer resistance, pore distribution, and moisture content characteristics were determined before and after for each of the three tillage. The penetration resistance was determined at the depths of 0-80 cm while the soil moisture was determined on the surface (0-20 cm). These properties were determined directly before and after tillage operations. All the tillage operations were significantly different in their effects on soil bulk density and soil penetration resistance. The soil bulk density decreased with the degree of soil manipulation after first and third tillage and increased after second tillage, with NT having the highest mean bulk density 1.04, 0.95 and 1.03 g/cm3 while TT having the least 0.84, 0.83 and 0.72 g/cm3 for 1st, 2nd and 3rd season respectively. The soil penetration resistance decreased due to tillage operation, with NT also having the highest resistance of 1.69 MPa and 1.44 Mpa in hardpan during 1st and 2nd season and the lowest PR was 0.09, 0.17 and 0.21 Mpa at TT in 1st, 2nd and 3rd season. Highest mean porosity was 0.68 in 2nd season at TT and the lowest mean porosity was 0.36 in 3rd season at NT. The lowest volumetric moisture content was at ST 0.26 and 0.27 in 1st and 2nd season at ST, and the highest was at TT 0.56, 0.57 and 0.68 at TT in 1st, 2nd and 3rd season respectively. The soil particle density was increased after three tillage operation. The highest increase (23.73%) was noted in FT 2nd season and the minimum was in TT in 1 st season (6.04%) while it decreased in ST during the three seasons.
Problem statement: Rotating turbine ventilators were generally found in most countries. They were simple in structure, light in weight and cheap to install. It was quite surprising that, the aerodynamics of this common device had not been numerically examined and the design process of most of these ventilators had developed progressively through trial and error methods. Approach: This study was concerned with performing simulation of airflow using CFD technique code name FLUENT so as to visualize the flow behavior around and within a rotating turbine ventilator in addition to determining the aerodynamic forces acting on this device during its operation. To achieve that, the realizable k-ε and RSM turbulence models were used by taking advantage of moving mesh method to simulate the rotation of turbine ventilator and the consequent results were obtained through the sequential process which ensured accuracy of the computations. Results: The results confirmed that, the realizable k-ε model can exhibit a reasonable performance, however not as competence as the RSM model, but of much less computation time. Conclusion/Recommendations: Results from this study, besides ensuring the reliability of utilizing the CFD method in design process of future turbine ventilators, would lead us to a conspicuous progress on increasing the efficiency at reduced cost of wind driven ventilators and similar devices
The present work is to demonstrate how some very simple problems are made mathematically complex and seemingly tedious due to academic or business compulsions. There are some problems in which mathematical model are developed after making many simplifying assumptions. But, when it comes to solving these models, very sophisticated and complex schemes are applied. For such problems, dual policy does not make sense and in many cases the problem may be tackled in a simpler way to get comparable accuracy. The present paper reports one such example. It deals with the development and authentication of computer software for estimating building cooling load. The software is simpler to use, needs fewer input data and is more versatile compared to any other commercially available, exorbitantly costly and extensively used software. The effects of significant building parameters like orientation, window glass shade type, number of glass panes used, wall insulation, roof type and floor type can be easily investigated. Effects of all these parameters have been investigated for a typical building block to arrive at an intelligent decision. With any other software or method, it cannot be made so conveniently. All the above mentioned advantages are without sacrificing accuracy and reliability
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