Application of graph theory to reliability analysis was first made in 1970 [1]. Over the years, a large number of computer programmes have been developed to determine the spanning trees, the minimal paths and cutsets, which are essential for determining the reliability of the network. In recent years, there has been an interest 2., 4. in developing small desk top calculators for specific purposes, which could be used by the designers of transportation systems, communication systems, etc. In this article the authors present an approach to design a microprocessor based equipment to determine minimal pathset and minimal cutset from the incidence matrix of the graph. The authors have presented a new design approach, based on search technique. The salient feature of the new approach is a novel tracing process in which the desired graph is traced by operating a set of constraints. The new design approach has already been used by the authors to develop a microprocessor based spanning tree generator 2., 3.. 相似文献
Defense Advanced Research Projects Agency (DARPA) is offering funding for interdisciplinary research in the area of hybrid insect MEMS (microelectromechanical systems). DARPA aims to have MEMS intimately integrated into insects during their early stages of metamorphoses. In principle, this should lead to a more reliable bio-electromechanical interface to the insect, as compared with the earlier DARPA-funded attempts to glue the electronic module to an adult insect. DARPA's final demonstration goal is the delivery of an insect within five meters of a specific target located a hundred meters away using electronic remote control and/or GPS. 相似文献
Existing uses of RF/microwave heating involve soft targets. This article focuses on current research being carried out in the United Kingdom and South Africa, where microwave energy is being applied to "soften up" rocks for the purpose of mineral extraction. 相似文献
This paper addresses the energy efficiency (EE) maximization problem for a multi-input multi-output cognitive two-way relay network. The secondary system, comprises of a two-way amplify-and-forward (AF) relay and two transceivers, co-exists with the licensed primary user (PU). The secondary transceivers communicate through the two-way AF relay. We jointly design the precoders for the secondary transceivers and the AF relay with the aim to maximize the EE while satisfying the transmit power constraints at the secondary transceivers and the relay, quality-of-service constraints at the secondary transceivers, and interference constraints at the PU. The resulting maximization problem is a non-convex fractional programming problem with three unknown precoder matrices. This problem is first simplified and converted into a vector valued problem using singular value decomposition. Further, the tools of iterative optimization scheme and the fractional programming theory are employed to solve the simplified problem. The computational complexity and convergence behaviour of the proposed solution are analysed. Numerical results are presented to illustrate the effectiveness of the proposed design in terms of the achievable EE and the probability of feasibility.
Many moth pheromones are composed of mixtures of acetates of long‐chain (≥10 carbon) fatty alcohols. Moth pheromone precursors such as fatty acids and fatty alcohols can be produced in yeast by the heterologous expression of genes involved in insect pheromone production. Acetyltransferases that subsequently catalyze the formation of acetates by transfer of the acetate unit from acetyl‐CoA to a fatty alcohol have been postulated in pheromone biosynthesis. However, so far no fatty alcohol acetyltransferases responsible for the production of straight chain alkyl acetate pheromone components in insects have been identified. In search for a non‐insect acetyltransferase alternative, we expressed a plant‐derived diacylglycerol acetyltransferase (EaDAcT) (EC 2.3.1.20) cloned from the seed of the burning bush (Euonymus alatus) in a yeast system. EaDAcT transformed various fatty alcohol insect pheromone precursors into acetates but we also found high background acetylation activities. Only one enzyme in yeast was shown to be responsible for the majority of that background activity, the acetyltransferase ATF1 (EC 2.3.1.84). We further investigated the usefulness of ATF1 for the conversion of moth pheromone alcohols into acetates in comparison with EaDAcT. Overexpression of ATF1 revealed that it was capable of acetylating these fatty alcohols with chain lengths from 10 to 18 carbons with up to 27‐ and 10‐fold higher in vivo and in vitro efficiency, respectively, compared to EaDAcT. The ATF1 enzyme thus has the potential to serve as the missing enzyme in the reconstruction of the biosynthetic pathway of insect acetate pheromones from precursor fatty acids in yeast. 相似文献
The application of hydrocolloid gel particles is potentially useful in food, chemical, and pharmaceutical industries. Alginate gel particles are one of the more commonly used hydrocolloid gel particles due to them being biocompatible, nontoxic, biodegradable, cheap, and simple to produce. They are particularly valued for their application in encapsulation. Encapsulation in alginate gel particles confers protective benefits to cells, DNA, nutrients, and microbes. Slow release of flavors, minerals, and drugs can also be achieved by encapsulation in gel particles. The particle size and shape of the gel particles are crucial for specific applications. In this review, current methods of producing alginate gel particles will be discussed, taking into account their advantages, disadvantages, scalability, and impact on particle size. The physical properties of alginate gel particles will determine the effectiveness in different application conditions. This review will cover the current understanding of the alginate biopolymer, gelation mechanisms and factors affecting release properties, gel strength, and rheology of the alginate gel particle systems. 相似文献
In this paper, a performance analysis of a metal hydride based hydrogen storage container with embedded cooling tubes during absorption of hydrogen is presented. A 2-D mathematical model in cylindrical coordinates is developed using the commercial software COMSOL Multiphysics 4.2. Numerical results obtained are found in good agreement with experimental data available in the literature. Different container geometries, depending upon the number and arrangement of cooling tubes inside the hydride bed, are considered to obtain an optimum geometry. For this optimum geometry, the effects of various operating parameters viz. supply pressure, cooling fluid temperature and overall heat transfer coefficient on the hydriding characteristics of MmNi4.6Al0.4 are presented. Industrial-scale hydrogen storage container with the capacity of about 150 kg of alloy mass is also modeled. In summary, this paper demonstrates the modeling and the selection of optimum geometry of a metal hydride based hydrogen storage container (MHHSC) based on minimum absorption time and easy manufacturing aspects. 相似文献