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排序方式: 共有5722条查询结果,搜索用时 250 毫秒
181.
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Ingudam Shakuntala Samir Das Sandeep Ghatak Rajkumari Sanjukta Kekungu-U Puro 《Food Biotechnology》2019,33(3):237-250
Listeria monocytogenes is a pathogenic microorganism infects man mostly through food. A total of 1615 samples of foods of animal origin and water were collected from retail meat shops of North-Eastern India and processed. Sixty-three (3.9%) samples were positive for L. monocytogenes. Animal origin foods showing the highest prevalence was chevon (9.8%) followed by beef (8.9%), chicken (8.5%), pork (2.8%) and milk (1.8%). The prevalence rate in water from retail meat shops was 10%. Recovered L. monocytogenes were distributed into 3 serogroups, of which 74.6% fit in to 1/2a, 3a serogroup, 17.5% to 1/2b, 3b and 7.9 % to 4b, 4d, 4e serogroups. Thirty-five isolates out of 63 possessed all the tested four virulence genes. RAPD- and ERIC -PCR based analyses jointly revealed a discriminative genetic profile for the L. monocytogenes. On the whole, the occurrence of L. monocytogenes in foods of animal origin of North Eastern India displays public health hazard. 相似文献
183.
Anupam Ojha Barun Das Shyamal Kumar Mondal Manoranjan Maiti 《Applied Soft Computing》2013,13(8):3703-3712
This paper presents the recently introduced modified subgradient method for optimization and its effectiveness in a fuzzy transportation model. Here a multi-item balanced transportation problem (MIBTP) is formulated where unit transportation costs are imprecise. Also available spaces and budgets at destinations are limited but imprecise. The objective is to find a shipment schedule for the items that minimizes the total cost subjected to imprecise warehouse and budget constraints at destinations. The proposed model is reduced to a multi-objective optimization problem using tolerances, then to a crisp single-objective one using fuzzy non-linear programming (FNLP) technique and Zimmermann's method. The above fuzzy MIBTP is also reduced to another form of deterministic one using modified sub-gradient method (MSM). These two crisp optimization problems are solved by Genetic Algorithm (GA). As an extension, fuzzy multi-item balanced solid transportation problems (STPs) with and without restrictions on some routes and items are formulated and reduced to deterministic ones following FNLP and Zimmermann's methods. These models are also solved by GA. Models are illustrated numerically, optimum results of fuzzy MIBTP from two deductions are compared. Results are also presented for different GA parameters. 相似文献
184.
Souvik Das Piyas Palit Suman Mukhopadhya Jitendra Mathur Arthita Dey Goutam Mukherjee Tanmay Bhattacharyya Sandip Bhattacharyya 《Journal of Failure Analysis and Prevention》2013,13(4):396-402
Reinforcing bars, popularly termed “rebars,” are used to impart tensile strength to concrete structures. Concrete has high resistance to weathering and fire and high compressive strength but almost no tensile strength, hence rebars are used to provide the latter to concrete. Property consistency along the length of rebars is an important prerequisite. When the finished product is subjected to thermomechanical treatment (TMT), proper control of rolling and water box parameters and efficient pinch rolling are needed to achieve acceptable properties. Variation of yield strength (YS) along TMT bars from the front to back end has been observed within the same heat treatment. In the presented investigation, it was observed that pinch rolling ineffectiveness is the main reason for the poor mechanical properties at the back end. The pinch roller was unable to support the back end of the TMT bars properly to maintain the speed and tension of the bars, resulting in nonuniform cooling of the back end through the water box and subsequent mechanical property failure. Due to the substandard material of the pinch roller, it was unable to hold the back end of the bar properly. Based on analysis of the roller it was concluded that it failed due to improper microstructure, resulting in inadequate hardness and toughness for the stringent operating conditions. AISI H13 is a better material to use in such high-service-temperature conditions. Moreover, proper heat treatment is needed to achieve adequate hardness and microstructure properties. After proper heat treatment of pinch rollers, their service life was increased twofold, minimizing the YS variation along the rebars. 相似文献
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Dillip K. Pradhan Banarji Behera Piyush R. Das 《Journal of Materials Science: Materials in Electronics》2012,23(3):779-785
A polycrystalline ceramic with a new type of complex tungsten-bronze type structure, having a general formula K2Ba2Nd2Ti4Nb4W2O30 has been prepared using a high temperature solid-state reaction route after optimizing the calcinations conditions on the
basis of thermal analysis results. The material has been characterized by different experimental techniques. The formation
of the compound has been confirmed using X-ray diffraction analysis. Dielectric properties (εr and tanδ) of the compound as a function of temperature at different frequencies have been carried out. Temperature dependence
of dielectric constant indicates the presence of ferroelectric phase transition well above the room temperature. Complex impedance
spectroscopic analysis has been carried out as a function of frequency at different temperatures to establish some correlation
between the microstructure and electrical properties of the material. The nature of frequency dependence of ac conductivity
obeys the Jonscher’s power law. The dc conductivity calculated from the ac conductivity spectrum shows the negative temperature
coefficient of resistance behavior like a semiconductor. 相似文献
188.
189.
A. K. Manna B. Das J. K. Dey S. K. Mondal 《Journal of Intelligent Manufacturing》2018,29(7):1515-1531
One of the economic production quantity problems that have been of interest to researchers is the production with reworking of the imperfect items including waste most disposal form and vending the units. The available models in the literature assumed that the decay rate of the items is satisfied from three different points of view: (i) minimum demands of the customer’s requirement, (ii) demands to be enhanced for lower selling price and (iii) demands of the customers who are motivated by the advertisement. The model is developed over a finite random planning horizon, which is assumed to follow the exponential distribution with known parameters. The model has been illustrated with a numerical example, whose parametric inputs are estimated from market survey. Here the model is optimized by using a population varying genetic algorithm. 相似文献
190.
Ram Avtar Jat Ripandeep Singh S.C. Parida A. Das Renu Agarwal K.L. Ramakumar 《International Journal of Hydrogen Energy》2014
In the present study, we have for the first time reported the occupancy of deuterium in a new interstitial site of ZrCoD3 which explain the hydrogen induced disproportionation behavior of ZrCo alloy. We have also reported the effect of Ni substitution on interstitial site occupancy of deuterium in ZrCo1−xNixD3, which in turn explains the improved durability of these Ni substituted deuterides against disproportionation. The crystal structure of the ZrCo1−xNix (x = 0.0, 0.1, 0.2, 0.3) deuterides was investigated by X-ray powder diffraction and neutron diffraction methods. The XRD data reveals a single phase formation for all deuterides with varying Ni content (x). The neutron diffraction study shows that deuterium occupies a new site 8e in addition to 4c2 and 8f1. Additionally, the Zr–D distance in 8e site is shorter than that in ZrD2. Therefore, increase in 8e site occupancy will in turn decreases the durability against disproportionation and vice-versa. Furthermore, the neutron diffraction reveals that occupancy of new 8e site decreases and its Zr–D distance increases with increase in Ni content, which explicate the higher durability against disproportionation for Ni rich compound. 相似文献