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排序方式: 共有322条查询结果,搜索用时 15 毫秒
61.
Arya Sidharthan Neelesh Dahanukar Remya Lathika Sundar Kutty Ranjeet Rajeev Raghavan 《河流研究与利用》2022,38(1):152-159
Riverscape genetics of fish, though extensively studied in temperate regions, have received limited interest in tropical rivers, especially in montane systems which not only harbour several endemic and threatened species, but are also subjected to extensive habitat modifications. We determine the population genetic structure of two endemic balitorid loaches (Bhavania australis and Travancoria elongata) in response to natural (25 m high waterfall) and artificial (23 m high and 290 m long hydropower dam) barriers in a small mountain riverscape in the Western Ghats Hotspot. Population genetics analysis using mitochondrial cytochrome b gene sequence showed low nucleotide diversity, haplotype diversity and genetic differentiation among populations, for both species, suggesting that barriers did not influence genetic structuring. Though migration analysis also revealed that barriers did not affect movement of the two species through the riverscape, patterns in mutation-scaled immigration rates and population sizes differed between the two species supporting our observation that they rarely co-exist in the same habitat, likely as an effect of competitive exclusion. Mismatch distribution and Bayesian skyline plot suggested recent expansion in the populations of B. australis and corresponding population decline in T. elongata in the last 100 years, which probably explains the widespread and abundant distribution of B. australis as opposed to the narrow endemism and rarity of T. elongata. Our results provide novel insights into the ecology of balitorid loaches and their response to riverine barriers in a tropical mountain landscape. 相似文献
62.
S.M. Deshmukh C.K. Ghatak P.R. Arya A. Subhananda Rao 《Journal of Energetic Materials》2013,31(4):321-331
In an attempt to replace toxic ingredients like lead ferrocyanide (LFCN) in electrical squibs, experiments were conducted by using barium ferrocyanide (BFCN) as an ingredient of squib composition. Electrothermal response (ETR), functional characteristics such as no-fire current (NFC) and all-fire current (AFC), were studied and compared with lead ferrocyanide-based squibs. Threshold firing currents were determined using the Bruceton staircase method. The squibs were also subjected to accelerated ageing and performance was evaluated. The results indicate better performance of barium ferrocyanide squibs to electrothermal response and a higher threshold no fire current, making it comparatively safe to handle as compared to lead ferrocyanide–based squibs. The results of accelerated ageing indicate a reasonable shelf life. ETR technique is found to be a good diagnostic tool for quality control. 相似文献
63.
64.
The picture fuzzy set (PFS) has grown huge attention in the research area of uncertain information from the last few years. Information measures have been widely studied in various fuzzy environments. Therefore, in this paper, we study the entropy and divergence measures under the picture fuzzy environment. First, the paper introduced a new entropy measure to measure the fuzziness degree associated with a PFS. An example is established to show the capabilities of the proposed entropy measure. Second, the paper defines a new Jensen–Tsalli divergence measure for PFS to evaluate the information of discrimination between two PFS. We also discuss several properties of entropy and divergence measures in detail. Then we present a new method, based on proposed entropy and divergence measure, to determine the objective weights of experts for multicriteria group decision making with picture fuzzy information. The final criteria weights are obtained by combining subjective and objective weights for more reliable weightage of evaluation criteria. By using this comprehensive weight-determination technique, the proposed method can effectively reduce the unreasonable impact of the extreme evaluation data on the evaluation results. Further, a new multi-criteria decision-making approach is developed based on the combining concepts of the TODIM and VIKOR method under the picture fuzzy environment. We used TODIM to obtain the overall dominance degree which considers the bounded rationality of decision makers and VIKOR is used to obtain the compromise ranking of alternatives. Lastly, an application of the proposed integrated model is demonstrated to verify the feasibility and usefulness and the outcomes of the proposed model are compared with the outcomes of the existing approaches to indicate its validity. This integrated method can effectively reduce the distortion of decision information and provide extraordinary evaluation results. The proposed approach is used in detecting the major issues due to which a company is facing such breakdowns. 相似文献
65.
Multimedia Tools and Applications - De-noising of images along with the edge enhancement has always been a challenging task in large scale heterogeneous image data. This paper presents a two stage... 相似文献
66.
The work reported in this paper is focused on the performance of a thermoacoustic refrigerator under various operating conditions. The experiments were conducted with various stack geometries fabricated with epoxy glass and Mylar material. Four stacks with different pore sizes are used to evaluate the performance of the refrigerator. Stack 1 has parallel plates of Mylar material 0.12 mm thick spaced 0.36 mm apart. Stacks 2, 3 and 4 are made of epoxy glass with pores of circular cross-section having 1, 2 and 3 mm diameter, respectively. The entire resonator system was constructed from aluminium material coated with polyurethane material from inside to reduce conduction heat losses. Helium gas was used as a working fluid. The experiments were conducted with different drive ratios ranging from 1.6% to 2% with varying cooling load from 2 to 10 W. For the experiments, operating frequencies from 200 to 600 Hz with mean pressure varying from 2 to 10 bar in steps of 2 bar each were considered. The temperatures of the hot end and cold end of the heat exchangers were recorded using RTDs and a data acquisition system under various operating conditions. The coefficient of performance (COP) and relative COP (COPR) are evaluated. Results show that COP of the refrigerator rises with increase of cooling load and decreases at higher drive ratio. It was also observed that the temperature difference between the hot end and cold end of the stack is higher at 2 W cooling load for 400 Hz operating frequency. The temperature difference between the hot end and cold end of the stack was observed to be 19.4, 17.2, 14 and 12.4°C for stacks 1, 2, 3 and 4, respectively, for 10 bar mean pressure and 2 W cooling load. The temperature difference and COP of the parallel plate stack are better compared with other stack geometries. 相似文献
67.
Multimedia Tools and Applications - This paper introduces a novel four stage filter algorithm to ameliorate images corrupted by very high density salt-and-pepper noise. The proposed algorithm... 相似文献
68.
Great strides have been made to realistically deploy multiple Unmanned Aerial Vehicles (UAVs) within the commercial domain, which demands a proper coordination and reliable communication among the UAVs. UAVs suffer from limited time of flight. Conventional techniques suffer from high delay, low throughput, and early node death due to aerial topology of UAV networks. To deal with these issues, this paper proposes a UAV parameter vector which considers node energy, channel state information and mobility of UAVs. By intelligently estimating the proposed parameter, the state of UAV can be predicted closely. Accordingly, efficient clustering may be achieved by using suitable metaheuristic techniques. In the current work, Elbow method has been used to determine optimal cluster count in the deployed FANET. The proposed UAV parameter vector is then integrated into two popular hybrid metaheuristic algorithms, namely, water cycle-moth flame optimization (WCMFO) and Grey Wolf-Particle Swarm optimization (GWPSO), thereby enhancing the lifespan of the system. A methodology based on the holistic approach of parameter and signal formulation, estimation model for intelligent clustering, and statistical parameters for performance analysis is carried out by the energy consumption of the network and the alive node analysis. Rigorous simulations are run to demonstrate node density variations to validate the theoretical developments for various proportions of network system sizes. The proposed method presents significant improvement over conventional state-of-the-art methods. 相似文献
69.
S. S. Arya S. Ramanujam P. K. Vijayaraghavan 《Journal of the American Oil Chemists' Society》1969,46(1):28-30
Common edible oils and fats (refined peanut oil, seasame oil, safflower oil, and butter oil, ghee) were exposed to direct
sunlight, fluorescent light and Schaal Test. Data collected on refractive indices (N
D
25
) show an increase of the order of 0.001±0.0003 at the stage of development of perceptible rancid odor. The pattern of changes
in refractive indices and peroxide values of these edible oils, autoxidized at 100±5 C, show that refractive indices indicate
more precisely the termination of the induction periods than peroxide values. 相似文献
70.
Yaghoubzadeh-Bavandpour Arya Bozorg-Haddad Omid Rajabi Mohammadreza Zolghadr-Asli Babak Chu Xuefeng 《Water Resources Management》2022,36(7):2275-2292
Water Resources Management - Real-world problems often contain complex structures and various variables, and classical optimization techniques may face difficulties finding optimal solutions.... 相似文献