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111.
Ad hoc bio-sensor networks have a very characteristic structure with three types of nodes: the command centre, the sensor nodes (animals such as rats) and the relaying nodes. We have taken up such networks and measured the throughput of such systems and suggest ways in which the throughput can be increased. It was also found that to increase the throughput of such systems, no sophisticated routing techniques or expensive transmission techniques are needed. This can be achieved by simply adopting the appropriate motion trajectories of the nodes. We have also explained the structure of these networks in detail and the routing issues involved in these networks. A Hot-Spot problem at the command centre has also been discussed. The suggestions of appropriate motions target this problem and show how an even distribution of nodes can alleviate this problem to a large extent. In addition to this, a constraint on the number of messages the sensor node can send per unit time can also make the network more efficient. 相似文献
112.
The networked manufacturing offers several advantages in current competitive atmosphere by way of reducing the manufacturing cycle time and maintenance of the production flexibility, thereby achieving several feasible process plans. In this paper, we have addressed a Multi Objective Problem (MOP) which covers-minimize the makespan and to maximize the machine utilization while generating the feasible process plans for multiple jobs in the context of network based manufacturing system. A new multi-objective based Territory Defining Evolutionary Algorithm (TDEA) to resolve the above computationally challenge problem have been developed. In particular, with two powerful Multi-Objective Evolutionary Algorithms (MOEAs), viz. Non-dominated Sorting Genetic Algorithm (NSGA-II) and Controlled Elitist-NSGA-II (CE-NSGA-II) the performance of the proposed TDEA has been compared. An illustrative example along with three complex scenarios is presented to demonstrate the feasibility of the approach. The proposed algorithm is validated and the results are analyzed and compared. 相似文献
113.
The aim of this paper is to optimize the number of collectors for PV/T hybrid active solar still. The number of PV/T collectors connected in series has been integrated with the basin of solar still. The optimization of number of collectors for different heat capacity of water has been carried out on the basis of energy and exergy. Expressions of inner glass, outer glass and water temperature have been derived for the hybrid active solar system. For the numerical computations data of a summer day (May 22, 2008) for Delhi climatic condition have been used. It has been observed that with increase of the mass of water in the basin increases the optimum number of collector. However the daily and exergy efficiency decreases linearly and nonlinearly with increase of water mass. It has been observed that the maximum yield occurs at N = 4 for 50 kg of water mass on the basis of exergy efficiency. The thermal model has also been experimentally validated. 相似文献
114.
The purpose of a cruise control system is to accurately maintain the driver’s desired set speed, without intervention from the driver, by actuating the throttle-accelerator pedal linkage. Over the past five years, owners of a particular cruise control have complained that it did not operate properly. Complaints ranged from not engaging upon command, to the cruise unexpectedly accelerating past the desired speed. A common thread among all the complaints was the intermittent nature of the problems. More than 96% of the reported failed modules removed from vehicles and returned to the company, passed bench tests.This paper presents a physics-of-failure process to identify, induce and analyze failure mechanisms causing intermittent failures, high warranty returns and cannot duplicate (CND) problems of the digital electronic cruise control module (CCM). In addition, we explain why the manufacturer’s tests were not representative of the actual automotive environments, nor were they conducted in a manner to access actual failures. We conclude with a recommendation for a physics-of-failure approach for future product development. 相似文献
115.
M. Din G.N. Tiwari M.K. Ghosal N.S.L. Srivastava Md. Imran Khan M.S. Sodha 《国际能源研究杂志》2003,27(1):79-92
In this communication, thermal model of a greenhouse has been developed by incorporating the effect of water wall in the north side. Various temperatures, namely plant, water wall and room temperatures as a function of climatic and design parameters have been obtained by solving coupled single-order differential equation using Runge–Kutta method. Numerical methods have been carried out for a typical day of winter for Delhi condition. It has been observed that there is significant effect in the plant, room air and water temperatures due to change in fraction of solar radiation incident on north wall (Fn) and heat capacity of water wall. Experimental validation of the proposed model for a greenhouse with brick north wall has also been carried out. It has been observed that there is a fair agreement between experimental and theoretical values. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
116.
A class of tests for the increasing failure rate average (IFRA) alternatives under random censoring is proposed. The tests are based on a function of the Kaplan-Meier estimator. Most of the IFRA tests in the literature depend on the (nuisance) parameter that appears in the definition of IFRA, and the choice of this parameter is crucial in performing the tests. The proposed class of tests does not have this disadvantage. Under some regularity conditions, the asymptotic normality of the tests is established and asymptotically distribution-free tests are obtained by using estimators for the null standard deviations. The efficacies of the tests under the proportional hazard censoring model are studied. The proposed test is most efficient for the Weibull family of IFRA alternatives among the existing tests available for the censored data. The test is applied to published appliance data 相似文献
117.
This study pertains to classification and antigenic analysis of mycobacterial plasma membrane proteins in relation to human T cell proliferative responses, using a 'fast grower' Mycobacterium fortuitum as model. Membrane vesicles, prepared by sonication and differential centrifugation, were subjected to biphasic Triton X-114 extraction for isolation of integral peripheral (aqueous phase) proteins. Neither protein pool showed any appreciable overlap serologically. SDS-PAGE showed five prominent bands in peripheral and three in the integral protein pool, whereas immunoblotting with rabbit antisera identified only two major antigens (60 and 67 kD) in the former and five (24, 34, 42, 51 and 54 kD) in the latter. ELISA with a panel of anti-mycobacterial MoAbs revealed that nine out of 12 previously known antigens were present in the peripheral protein pool. Only two of them (33 and 40 kD) were additionally detected amongst integral proteins. The membrane-associated immunosuppressive moiety lipoarabinomannan was semiquantitatively located in aqueous phase. In bulk T cell proliferation assays, seven out of 10 subjects belonging to a 'responder' background (BT-BB leprosy patients and healthy contacts) showed high responses for Myco. fortuitum antigens. Proliferative response with integral proteins was comparable to that with whole membrane, but it was significantly higher (P < 0.0005) than the response with peripheral proteins. The distinction and relevance of integral membrane proteins as a class of mycobacterial antigens make them worthy of consideration in a subunit vaccine design. 相似文献
118.
S. P. Srivastava T. Butz G. B. Tiwari H. -J. Oschmann I. Rahimian S. D. Phatak 《Petroleum Science and Technology》2002,20(3):269-290
The compositional analysis of aromatics, saturates and urea non adductables obtained from vacuum gas oil (VGO) distillate (370-550°C) and its seven sub-fractions: (1) 370-400, (2) 400-425, (3) 425-450, (4) 450-475, (5) 475-500, (6) 500-525 and (7) 525-550°C, derived from both paraffinic and aromatic base crude oils have been done using thin layer chromatography/flame ionisation detection technique. The physico- chemical characteristics are measured using the ASTM/ standard test procedures and an attempt has been made to correlate the physico-chemical properties with the composition. The phenomenon of gel formation at low temperatures and the characteristics of the gel in these VGO sub-fractions have been studied by X-ray diffractometry and photomicrography. It is found that at low temperatures the gel formation takes place due to the development of a three dimensional network by the crystallizing n-paraffins, as well as by the agglomeration of molecules due to very high viscosity. Both processes proceed simultaneously and the concentration and composition of n-paraffins have been found to determine the dominance or otherwise of the crystallization process. 相似文献
119.
The techno-economic analysis of a solar distillation system incorporating the effect of subsidy, rainfall water, salvage value and maintenance costs of the system is presented. The analysis is carried out by two methods, namely the marginal efficiency of capital and the average cost per year. The rate of inflation in maintenance costs is also incorporated. It is observed that the cost per kWh for producing distilled water as calculated by the average cost per year method is lower than that calculated using the marginal efficiency method. Irrespective of earlier research, it is established that the rate of increase in maintenance costs reduces the optimum lifetime of the system, and, for a practical system, the rate of increase in the maintenance costs must exceed the inflation rate and cannot be taken as constant. 相似文献
120.
Origin of room-temperature ferromagnetism in cobalt-doped ZnO 总被引:1,自引:0,他引:1
Thin films of ZnO doped with cobalt have been grown by the pulsed laser deposition (PLD) technique in different temperatures
ranging from 500°C to 650°C. The films grown on sapphire c-plane single crystal were found to be highly epitaxial. Magnetic
properties of these films were studied, and the films exhibited ferromagnetic characteristics at room temperature. Detailed
structural and microstructural characterization was performed to correlate the fate of the magnetic impurities, i.e., cobalt,
and the cause of magnetic properties. It is established from this work that the magnetic properties of these films are inherent
to the system, and any presence of second phase/nanoclusters/precipitates are ruled out as the cause of magnetic properties.
The techniques used to establish these were conventional and high-resolution transmission electron microscopy (HRTEM) along
with electron-energy loss spectroscopy (EELS) and scanning transmission electron microscopy-atomic number (STEM-Z) contrast
studies. 相似文献