oalib

OALib Journal期刊

ISSN: 2333-9721

费用:99美元

投稿

匹配条件: “Leila Taslim” ,找到相关结果约2067条。
列表显示的所有文章,均可免费获取
第1页/共2067条
每页显示
ON ASYMMETRIC METRIC SPACES
Leila Taslim
Journal of Global Research in Mathematical Archives , 2013,
Abstract: In this literature, we study asymmetric metric spaces. Next, we prove some important and practical results in these spaces. Finally, we obtain an interesting result by the concept of denseness in asymmetric metric spaces. Keywords: Asymmetric metric spaces, Forward and backward limits, Forward and backward denseness.
Farmer Water Management Strategies for Dry Season Water Shortages in Central Lombok, Indonesia  [PDF]
John Klock, Taslim Sjah
Natural Resources (NR) , 2011, DOI: 10.4236/nr.2011.22016
Abstract: This paper examines how farmers in central Lombok have organized themselves to manage agricultural water colle- ctively and to adapt to seasonally dry conditions. We interviewed eighteen village heads from October to December 2006. One of our questions we posed prior to field interviews was what might be the social and technical coping strategies that have allowed farmers to survive the lengthy dry seasons under the high population density of Lombok island. Some examples of organizational structure and practices in Central Lombok are presented. There were several common water management strategies that were revealed from these interviews including: methods of organization, flexible cropping systems, water allocation mechanisms, methods of compromise, alternative payments, and traditional water management practices. The statistical analysis comparing village characteristics and coping strategies suggests a relation between mosque number per village and farmers ability to cope. Farmers have shown their own unique coping strategies in times of water shortages and under decentralization occurring over the past decade. This decentralization involved turning over small scale irrigation systems (under 500 hectares), to the water user associations themselves in order to facilitate more efficient management and maintenance.
Discharge Coefficient Measurements for Flow Through Compound-Angle Conical Holes with Cross-Flow
Taslim M.,Ugarte S.
International Journal of Rotating Machinery , 2004,
Abstract:
A New Statistical-Based Correlation for the Rib Fin Effects on the Overall Heat Transfer Coefficient in a Rib-Roughened Cooling Channel
M. E. Taslim,V. Nezym
International Journal of Rotating Machinery , 2007, DOI: 10.1155/2007/68684
Abstract: Heat transfer coefficients in the cooling cavities of turbine airfoils are greatly enhanced by the presence of discrete ribs on the cavity walls. These ribs introduce two heat transfer enhancing features: a significant increase in heat transfer coefficient by promoting turbulence and mixing, and an increase in heat transfer area. Considerable amount of data are reported in open literature for the heat transfer coefficients both on the rib surface and on the floor area between the ribs. Many airfoil cooling design software tools, however, require an overall average heat transfer coefficient on a rib-roughened wall. Dealing with a complex flow circuit in conjunction with 180∘ bends, numerous film holes, trailing-edge slots, tip bleeds, crossover impingement, and a conjugate heat transfer problem; these tools are not often able to handle the geometric details of the rib-roughened surfaces or local variations in heat transfer coefficient on a rib-roughened wall. On the other hand, assigning an overall area-weighted average heat transfer coefficient based on the rib and floor area and their corresponding heat transfer coefficients will have the inherent error of assuming a 100% fin efficiency for the ribs, that is, assuming that rib surface temperature is the same as the rib base temperature. Depending on the rib geometry, this error could produce an overestimation of up to 10% in the evaluated rib-roughened wall heat transfer coefficient. In this paper, a correction factor is developed that can be applied to the overall area-weighted average heat transfer coefficient that, when applied to the projected rib-roughened cooling cavity walls, the net heat removal from the airfoil is the same as that of the rib-roughened wall. To develop this correction factor, the experimental results of heat transfer coefficients on the rib and on the surface area between the ribs are combined with about 400 numerical conduction models to determine an overall equivalent heat transfer coefficient that can be used in airfoil cooling design software. A well-known group method of data handling (GMDH) scheme was then utilized to develop a correlation that encompasses most pertinent parameters including the rib geometry, rib fin efficiency, and the rib and floor heat transfer coefficients.
Discharge Coefficient Measurements for Flow Through Compound-Angle Conical Holes with Cross-Flow
M. E. Taslim,S. Ugarte
International Journal of Rotating Machinery , 2004, DOI: 10.1155/s1023621x04000156
Abstract: Diffusion-shaped film holes with compound angles are currently being investigated for high temperature gas turbine airfoil film cooling. An accurate prediction of the coolant blowing rate through these film holes is essential in determining the film effectiveness. Therefore, the discharge coefficients associated with these film holes for a range of hole pressure ratios is essential in designing airfoil cooling circuits. Most of the available discharge coefficient data in open literature has been for cylindrical holes. The main objective of this experimental investigation was to measure the discharge coefficients for subsonic as well as supersonic pressure ratios through a single conical-diffusion hole. The conical hole has an exit-to-inlet area ratio of 4, a nominal flow length-to-inlet diameter ratio of 4, and an angle with respect to the exit plane (inclination angle) of 0°, 30°, 45°, and 60°. Measurements were performed with and without a cross-flow. For the cases with a cross-flow, discharge coefficients were measured for each of the hole geometries and 5 angles between the projected conical hole axis and the cross-flow direction of 0°, 45°, 90°, 135°, and 180°. Results are compared with available data in open literature for cylindrical film holes as well as limited data for conical film holes.
A Combined Numerical and Experimental Study of Heat Transfer in a Roughened Square Channel with Ribs
M. E. Taslim,H. Liu
International Journal of Rotating Machinery , 2005, DOI: 10.1155/ijrm.2005.60
Abstract: Experimental investigations have shown that the enhancement in heat transfer coefficients for air flow in a channel roughened with low blockage (e/Dh<0.1) angled ribs is on the average higher than that roughened with 90∘ ribs of the same geometry. Secondary flows generated by the angled ribs are believed to be responsible for these higher heat transfer coefficients. These secondary flows also create a spanwise variation in the heat transfer coefficient on the roughened wall with high levels of the heat transfer coefficient at one end of the rib and low levels at the other end. In an effort to investigate the thermal behavior of the angled ribs at elevated Reynolds numbers, a combined numerical and experimental study was conducted. In the numerical part, a square channel roughened with 45∘ ribs of four blockage ratios (e/Dh) of 0.10,0.15,0.20, and 0.25, each for a fixed pitch-to-height ratio (P/e) of 10, was modeled. Sharp as well as round-corner ribs (r/e=0 and 0.25) in a staggered arrangement were studied. The numerical models contained the smooth entry and exit regions to simulate exactly the tested geometries. A pressure-correction-based, multiblock, multigrid, unstructured/adaptive commercial software was used in this investigation. Standard high Reynolds number k−ε turbulence model in conjunction with the generalized wall function for most parts was used for turbulence closure. The applied thermal boundary conditions to the CFD models matched the test boundary conditions. In the experimental part, a selected number of these geometries were built and tested for heat transfer coefficients at elevated Reynolds numbers up to 150 000, using a liquid crystal technique. Comparisons between the test and numerically evaluated results showed reasonable agreements between the two for most cases. Test results showed that (a) 45∘ angled ribs with high blockage ratios (>0.2) at elevated Reynolds numbers do not exhibit a good thermal performance, that is, beyond this blockage ratio, the heat transfer coefficient decreases with the rib blockage and (b) CFD could be considered as a viable tool for the prediction of heat transfer coefficients in a rib-roughened test section.
A Combined Numerical and Experimental Study of Heat Transfer in a Roughened Square Channel with 45 ° Ribs
Taslim M. E.,Liu H.
International Journal of Rotating Machinery , 2005,
Abstract: Experimental investigations have shown that the enhancement in heat transfer coefficients for air flow in a channel roughened with low blockage ( e/ D h <0.1 ) angled ribs is on the average higher than that roughened with 90 ° ribs of the same geometry. Secondary flows generated by the angled ribs are believed to be responsible for these higher heat transfer coefficients. These secondary flows also create a spanwise variation in the heat transfer coefficient on the roughened wall with high levels of the heat transfer coefficient at one end of the rib and low levels at the other end. In an effort to investigate the thermal behavior of the angled ribs at elevated Reynolds numbers, a combined numerical and experimental study was conducted. In the numerical part, a square channel roughened with 45 ° ribs of four blockage ratios ( e/ D h ) of 0.10,0.15,0.20 , and 0.25 , each for a fixed pitch-to-height ratio ( P/e ) of 10 , was modeled. Sharp as well as round-corner ribs ( r/e =0 and 0.25 ) in a staggered arrangement were studied. The numerical models contained the smooth entry and exit regions to simulate exactly the tested geometries. A pressure-correction-based, multiblock, multigrid, unstructured/adaptive commercial software was used in this investigation. Standard high Reynolds number k turbulence model in conjunction with the generalized wall function for most parts was used for turbulence closure. The applied thermal boundary conditions to the CFD models matched the test boundary conditions. In the experimental part, a selected number of these geometries were built and tested for heat transfer coefficients at elevated Reynolds numbers up to 150 000, using a liquid crystal technique. Comparisons between the test and numerically evaluated results showed reasonable agreements between the two for most cases. Test results showed that (a) 45 ° angled ribs with high blockage ratios ( >0.2 ) at elevated Reynolds numbers do not exhibit a good thermal performance, that is, beyond this blockage ratio, the heat transfer coefficient decreases with the rib blockage and (b) CFD could be considered as a viable tool for the prediction of heat transfer coefficients in a rib-roughened test section.
Conversion of ethanol to acetone & other produces using nano-sensor SnO2(110): Ab initio DFT  [PDF]
Leila Mahdavian
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.36065
Abstract: The material considered in this study, SnO2 (110), has a widespread use as gas sensor and oxygen vacancies are known to act as active catalytic sites for the adsorption of small mo-lecules. In the following calculations crystal line SnO2 nano-crystal have been considered. The grains lattice, which has the rutile structure of the bulk material, includes oxygen vacancies and depositing a gaseous molecule, either ethanol, above an atom on the grain surface, generates the adsorbed system. The conduc-tance has a functional relationship with the structure and the distance molecule of the na-no- crystal and its dependence on these quanti-ties parallels the one of the binding energy. The calculations have quantum mechanical detail and are based on a semi-empirical (MNDO me-thod), which is applied to the evaluation of both the electronic structure and of the conductance. We study the structural, total energy, thermo-dynamic and conductive properties of absorp-tion C2H5OH on nano-crystal, which convert to acetaldehyde and acetone.
Inflation Targeting as the Monetary Policy Framework: Bangladesh Perspective
Mohammed SAIFUL ISLAM,Mohammad Taslim UDDIN
Economia : Seria Management , 2011,
Abstract: Inflation targeting strategy has become a widely accepted monetary policy framework in many countries all over the world. Our study finds that the central bank of Bangladesh is neither inflation targeting nor does follow any other rule-guided monetary policy, rather the policy is formulated with substantial discretion under the guidelines of donor agencies. This paper provides the evidence that monetary sector of Bangladesh economy has gained considerable degree of maturity and fulfils a number of prerequisites to adopt inflation targeting strategy. Using data over 1980-2010 we estimate an error correction model in order to examine if interest rate policy could fight the inflation. This is evident that deviation in inflation from target can be corrected via the changes in interest rate. Empirical findings jointly with few descriptive statistics provide strong evidence to recommend inflation targeting as the monetary policy strategy for Bangladesh.
Kondisi arus pasang surut di perairan pesisir kota Makassar , Sulawesi Selatan
Taslim Arifin,Yulius,M. Furqon Azis Ismail
Depik Jurnal , 2012,
Abstract: Numerical hydrodynamics model MOHID based on General Ocean Turbulence Model formula was used to study the tidal current in Makassar waters. The data used in this model are tidal elevation and bathymetry data from GEBCO. The tidal current simulation was conducted for 30 days. Model simulation results show that the tidal current velocity ranged between 0,001 m/s – 0,012 m/s. The current velocity during neap tide is smaller than the velocity during spring tide. The pattern of tidal current in Makassar waters is dominantly flows towards westward and then turned heading northward direction. The simulation result of tide-induced residual current in verification point shows that the flows is ebb-dominant at a rate of 0,005 m/s heading westward direction.
第1页/共2067条
每页显示


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.