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排序方式: 共有679条查询结果,搜索用时 15 毫秒
601.
Gadadhar Sahoo Shun Fujieda Kozo Shinoda Shinichi Yamaguchi Masao Korosaki Shigeru Suzuki 《Corrosion Science》2011,53(12):4001-4009
X-ray diffraction (XRD) and solution analysis were used for characterizing the influence of different silicon species on oxidation of green rust (GRI(Cl−)) suspension. While addition of silicon to metallic iron enhanced the formation of β-FeOOH, GRI(Cl−) in aqueous solution oxidized into lepidocrocite and oxidation was delayed in presence of silica and silicate species as noticed from potential, pH, and dissolved oxygen (DO) measurements. Transmission electron micrographs showed that the particle size of lepidocrocite was reduced due to silicate addition. The influence of silicate was attributed to its adsorption on GRI(Cl−) and lepidocrocite particles as confirmed from ICP-AES analysis of supernatant solution. 相似文献
602.
Bikash Sahoo Robert A. Van Gorder H.I. Andersson 《International Communications in Heat and Mass Transfer》2012
The steady revolving flow and heat transfer of a non-Newtonian Reiner–Rivlin fluid is studied. The momentum equation gives rise to a highly nonlinear boundary value problem. Attempt has been made to study the properties of the solution of the momentum equation analytically before proceeding for numerical solution. The effects of non-Newtonian fluid characteristic on the velocity and temperature fields have been discussed in detail and shown graphically. 相似文献
603.
This paper presents a performance-based plastic design (PBPD) methodology for the design of buckling-restrained braced frames (BRBFs). The design base shear is obtained based on energy–work balance using pre-selected target drift and yield mechanism. Three low-to-medium rise BRBFs (3-story, 6-story and 9-story) were designed by the proposed methodology and their seismic performance was evaluated through extensive nonlinear time-history analyses using forty ground motions representing the DBE and the MCE hazard levels. Both isotropic and kinematic hardening characteristics of buckling-restrained braces were considered in the modeling of their force–deformation behaviors. All BRBFs considered in this study reached the intended performance objectives in terms of yield mechanisms and target drift levels. Since PBPD is a direct design method, no iterations were carried out to achieve the performance objectives of BRBFs. 相似文献
604.
Pratap Kumar Sahu Eric Hsiao-Kuang Wu Jagruti Sahoo Mario Gerla 《Telecommunication Systems》2012,50(4):267-284
The emerging adoption of wireless communications on surface transportation systems has generated extensive interest among researchers over the last several years. Innovative inter-vehicular communications and vehicle-to-infrastructure communications achieve road traffic safety, ecstatic driving and delightful travelling experiences. Multi-hop information dissemination in vehicular ad hoc networks is challenged by high mobility and frequent disconnections of wireless nodes. This paper presents a new routing scheme for Highway/Freeway VANETs, which consists of a unicast destination discovery process, a robust forward node selection mechanism and a positional hello mechanism. In this paper, no dedicated path is framed in order to prevent frequent path maintenance. In addition, the avoidance of flooding and location services substantially reduces the control overhead. Positional hello scheme ensures connectivity and diminishes control overhead concurrently. Simulation results signify the benefits of the proposed routing strategy (i.e. DDOR) has higher packet delivery ratio, reduced routing overhead and shorter delay compared with previous works. 相似文献
605.
Ramesh C. Srivastava Sheelabhadra Mohanty Ramlal B. Singandhuppe Rajiv K. Mohanty Madhu S. Behera Lala I. P. Ray Deepika Sahoo 《Water Resources Management》2010,24(12):3017-3032
India has one of the largest and most ambitious irrigation programme in the world with net irrigated area exceeding 47 million
hectares. However, the overall project efficiency from the headwork to the farmer’s field has been quite low which leads to
not only poor utilization of irrigation potential created at huge cost, but also aggravates the degradation of soil and water
resources and thereby endangers the sustainability of agricultural production system. As the cost of creating additional irrigation
potential in terms of financial, human and environmental aspects has increased tremendously, need of the hour is to increase
the irrigation efficiency of existing projects and use saved water for irrigating new areas or meeting the demand of non-agricultural
sector. The contribution of application efficiency to poor irrigation efficiency is quite high and therefore increasing application
efficiency by a shift in application method from surface to pressurized system has potential of vastly improving irrigation
efficiency. To evaluate feasibility of this concept, a pilot study was initiated at Water Technology Centre for Eastern Region,
Bhubaneswar, on one outlet of a minor irrigation command. The system has been designed in such a way that it provides pipe
conveyance and surface irrigation for rice cultivation during monsoon season and pressurized irrigation during post monsoon
period through a hybrid system of sprinkler and drip with four outlets for sprinkler irrigating 2.8 ha area and two outlets
for drip irrigating 1.9 ha area. The system is also capable of providing irrigation through drip to part of a command during
summer for third crop using water stored in service reservoir after the canal is closed in first week of April. To take care
of sediment in the canal water, there are three stages of filtration: first by hydrocyclone filter which filters heavy suspended
materials viz. sand, silt, etc., then by the sand filter and finally by the screen filter. The filtration at three stages
reduces the turbidity to the desired level. It has been found that three-stage filtration reduced the turbidity to two NTU
which is within permissible limit. Considering the cost of water saved, a benefit-cost ratio of the system was found out to
be 1.126. This B: C ratio can be further increased by increasing the productivity of the fish and papaya in service reservoir
area and better crop management during summer season. 相似文献
606.
The present article evaluates the influence of independent control factors such as percentage of primary alpha phase, impact velocity, impingement angle, and erodent size on solid particle erosion behavior of Ti-6Al-4V alloy using a statistical approach. Microstructural variation in terms of different percentage of primary alpha phase of investigated alloy has been introduced by solution annealing it at different temperatures followed by thermal aging. Solid particle erosion tests have been carried out using a sand blast–type test rig following an experimental schedule based on Taguchi's orthogonal arrays. It is observed that erosion rate and the value of percentage elongation decreased with an increase in the content of primary alpha phase from 10 to 20% and then increased for the value corresponding to the content of 30% primary alpha phase in this alloy. We observed that the solid particle erosion behavior of the investigated alloy consisting of various percentages of primary alpha phase is related to their ductility. Among all four control factors, impact velocity of the erodent has been found to be the most significant control factor influencing the solid particle erosion behavior of this alloy followed by impingement angle, percentage of primary alpha phase, and erodent size. Impact velocity has greatest static influence of 91.35%, impingement angle has an influence of 4.69%, percentage of primary alpha phase has an influence of 2.28%, and erodent size has an influence of 0.42% on solid particle erosion having R2 = 0.99. Material loss during solid particle erosion of this alloy was found to be ductile in nature. Ploughing or pile-up leading to platelet formation is the primary mechanism of material loss during erosion of the alloy. 相似文献
607.
The dielectric relaxation characteristics of conductive carbon black (CCB) reinforced ethylene acrylic elastomer (AEM) vulcanizates have been studied as a function of frequency (101–106 Hz) at different filler loading over a wide range of temperatures (30–120°C). The effect of filler loadings on the dielectric permittivity (ε′), loss tangent (tan δ), complex impedance (Z*), and electrical conductivity (σac) were studied. The variation of ε′ with filler loading has been explained based on the interfacial polarization of the fillers within a heterogeneous system. The effect of filler loading on the imaginary (Z″) and real (Z′) part of Z* were distinctly visible, which may be due to the relaxation dynamics of polymer chains at the polymer–filler interface. The frequency dependency of σac has been investigated using percolation theory. The phenomenon of percolation in the composites has been discussed in terms of σac. The percolation threshold (?crit) occurred in the range of 20–30 phr (parts per hundred) of filler loading. The effect of temperature on tan δ, ε′, σac, and Nyquist plots of CCB‐based AEM vulcanizates has been investigated. The CCB was uniformly dispersed within the AEM matrix as studied from the transmission electron microscope (TEM) photomicrographs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
608.
A Computational study to investigate the heat loss due to radiation and steady laminar natural convection flow in a trapezoidal cavity having eight absorber tubes for a Linear Fresnel Reflector (LFR) solar thermal system with uniformly heated tubes and adiabatic top wall and side walls has been performed. The losses due to convection and radiation were considered from the bottom glass cover. The results are validated with experimental data. Radiative component of losses from the cavity was found to be dominant which contributes around 80–90%. Heat loss characteristics have been studied for cavities of different depths. Simulations have been carried out for various values of heat transfer coefficient based on the wind speed below the glass surface. Effect of emissivities of the tubes on the heat loss has also been simulated. Flow pattern and isotherms inside the cavity for various depths have been analyzed. Finally, the correlation between the total average Nusselt number and its influencing parameters has been obtained for the proposed cavity. 相似文献
609.
Process optimization for biodiesel production from Jatropha, Karanja and Polanga oils 总被引:2,自引:0,他引:2
P.K. Sahoo 《Fuel》2009,88(9):1588-1594
Petroleum sourced fuels is now widely known as non-renewable due to fossil fuel depletion and environmental degradation. Renewable, carbon neutral, transport fuels are necessary for environmental and economic sustainability. Biodiesel derived from oil crops is a potential renewable and carbon neutral alternative to petroleum fuels. Chemically, biodiesel is monoalkyl esters of long chain fatty acids derived from renewable feed stock like vegetable oils and animal fats. It is produced by transesterification in which, oil or fat is reacted with a monohydric alcohol in presence of a catalyst. The process of transesterification is affected by the mode of reaction condition, molar ratio of alcohol to oil, type of alcohol, type and amount of catalysts, reaction time and temperature and purity of reactants. In the present paper various methods of preparation of biodiesel from non-edible filtered Jatropha (Jatropha curcas), Karanja (Pongamia pinnata) and Polanga (Calophyllum inophyllum) oil have been described. Mono esters (biodiesel) produced and blended with diesel were evaluated. The technical tools and processes for monitoring the transesterification reactions like TLC, GC and HPLC have also been used. 相似文献
610.
In recent years, high utility itemsets (HUIs) mining from the transactional databases becomes one of the most emerging research topic in the field of data mining due to its wide range of applications in online e-commerce data analysis, identifying interesting patterns in biomedical data and for cross marketing solutions in retail business. It aims to discover the itemsets with high utilities efficiently by considering item quantities in a transaction and profit values of each item. However, it produces a tremendous number of HUIs, which imposes further burden in analysis of the extracted patterns and also degrades the performance of mining methods. Mining the set of closed + high utility itemsets (CHUIs) solves this issue as it is a loss-less and condensed representation of all HUIs. In this paper, we aim to present a new algorithm for finding CHUIs from a transactional database, called the CHUM (Closed + High Utility itemset Miner), which is scalable and efficient. The proposed mining algorithm adopts a tricky aimed vertical representation of the database in order to speed up the execution time in generating itemset closures and compute their utility information without accessing the database. The proposed method makes use of the item co-occurrences strategy in order to further reduce the number of intersections needed to be performed. Several experiments are conducted on various sparse and dense datasets and the simulation results clearly show the scalability and superior performance of our algorithm as compared to those for the existing state-of-the-art CHUD (Closed + High Utility itemset Discovery) algorithm. 相似文献