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排序方式: 共有699条查询结果,搜索用时 31 毫秒
111.
Impact of reform and privatization on consumers: A case study of power sector reform in Orissa,India
Orissa is the first state in India to have undergone reform in the power sector, with the government withdrawing its control. The model of this reform is known as the WB–Orissa model. The goal of this paper is to examine the impact of this reform on consumers of electricity, which has been measured using multiple regression models. The variables represent the parameters that consumers are most interested in, and the regression coefficients represent the weights of the corresponding variables. The data were collected using a survey methodology. The impact of reform was found to be mixed. Some groups of consumers saw benefits, while others felt a negative impact. A focus group study was conducted to identify the variables of interest to consumers of electricity. The model was used to estimate consumer benefit and was validated using primary data and structural equation modeling. The study revealed beneficial aspects of reform and areas with no benefits. 相似文献
112.
Piyasi Mukhopadhyay Kishor Sarkar Mousumi Chakraborty Sourav Bhattacharya Roshnara Mishra P.P. Kundu 《Materials science & engineering. C, Materials for biological applications》2013,33(1):376-382
We have developed self-assembled chitosan/insulin nanoparticles for successful oral insulin delivery. The main purpose of our study is to prepare chitosan/insulin nanoparticles by self-assembly method, to characterize them and to evaluate their efficiency in vivo diabetic model. The size and morphology of the nanoparticles were analyzed by dynamic light scattering (DLS), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The average particle size ranged from 200 to 550 nm, with almost spherical or sub spherical shape. An average insulin encapsulation within the nanoparticles was ~ 85%. In vitro release study showed that the nanoparticles were also efficient in retaining good amount of insulin in simulated gastric condition, while significant amount of insulin release was noticed in simulated intestinal condition. The oral administrations of chitosan/insulin nanoparticles were effective in lowering the blood glucose level of alloxan-induced diabetic mice. Thus, self-assembled chitosan/insulin nanoparticles show promising effects as potential insulin carrier system in animal models. 相似文献
113.
A good grade coke produces highest thermal energy and it is highly efficient in hot metal reduction. In order to concentrate the carbon in coke, the coke making process involves carbonisation of coal to high temperature (1100°C) in an oxygen-free atmosphere. There is always a need to efficiently automate the coke oven operations as much as possible. In order to improve the level of control and management of coke oven, the research on intelligent control system is carried out. In modern advanced control system of coke oven, the control scheme of combination of feedback and feed-forward merged with management is widely utilised. The integrated management and control system of coke oven is introduced systematically, including the production plan and scheduling management (dynamic scheduling) and heating control system (mathematical modelling) i.e. evaluating battery temperature, intelligent combustion control system and the pressure control of gas collector of coke oven battery. 相似文献
114.
Biswas A Nath B Bhattacharya P Halder D Kundu AK Mandal U Mukherjee A Chatterjee D Jacks G 《Environmental science & technology》2012,46(1):434-440
A low-cost rapid screening tool for arsenic (As) and manganese (Mn) in groundwater is urgently needed to formulate mitigation policies for sustainable drinking water supply. This study attempts to make statistical comparison between tubewell (TW) platform color and the level of As and Mn concentration in groundwater extracted from the respective TW (n = 423), to validate platform color as a screening tool for As and Mn in groundwater. The result shows that a black colored platform with 73% certainty indicates that well water is safe from As, while with 84% certainty a red colored platform indicates that well water is enriched with As, compared to WHO drinking water guideline of 10 μg/L. With this guideline the efficiency, sensitivity, and specificity of the tool are 79%, 77%, and 81%, respectively. However, the certainty values become 93% and 38%, respectively, for black and red colored platforms at 50 μg/L, the drinking water standards for India and Bangladesh. The respective efficiency, sensitivity, and specificity are 65%, 85%, and 59%. Similarly for Mn, black and red colored platform with 78% and 64% certainty, respectively, indicates that well water is either enriched or free from Mn at the Indian national drinking water standard of 300 μg/L. With this guideline the efficiency, sensitivity, and specificity of the tool are 71%, 67%, and 76%, respectively. Thus, this study demonstrates that TW platform color can be potentially used as an initial screening tool for identifying TWs with elevated dissolved As and Mn, to make further rigorous groundwater testing more intensive and implement mitigation options for safe drinking water supplies. 相似文献
115.
Wan Mohd Zamri W. Ismail Yee‐Sern Ng Sumona Mukherjee Anirban Kundu Soumyadeep Mukhopadhyay Bhaskar Sen Gupta Mohd Ali Hashim Ismail Yusoff 《Water and Environment Journal》2020,34(1):57-65
Malaysia contains elevated levels of iron in shallow groundwater in the range of 3–7 mg Fe/L compared to the USEPA safe limit of 0.3 mg Fe/L. Air Kelantan Sdn Bhd in Malaysia uses the ‘River Bank Filtration’ (RBF) technology to harvest hyporheic water. The RBF treatment removes the turbidity of the river water through the river bed acting as a filter, but is unable to remove the Fe from the harvested water. This work proposes a technology to reduce Fe concentration in the extracted water using granular activated carbon in a laboratory‐scale rotating packed bed contactor (RPBC). The Taguchi method was used for optimizing the operating conditions for the adsorption of Fe onto activated carbon in the RPBC system. Taguchi optimization results showed that a removal efficiency of 87% Fe from a 50 mg Fe/L concentration could be achieved by a RPBC at an initial pH of 6.5, a feed rate of 40 L/h, a rotating speed of 1600 rpm and a packing density of 357 kg/m3. 相似文献
116.
The viscoelastic properties of polymer thin films can have a significant impact on the performance in many small-scale devices. In this work, we use a phenomenon based on a thermally induced instability, termed thermal wrinkling, to measure viscoelastic properties of polystyrene films as a function of geometric confinement via changes in film thickness. With application of the appropriate buckling mechanics model for incompressible and geometrically confined films, we estimate the stress-relaxation modulus of polystyrene films by measuring the time-evolved wrinkle wavelength at fixed annealing temperatures. Specifically, we use time-temperature superposition to shift the stress relaxation curves and generate a modulus master curve for polystyrene films investigated here. On the basis of this master curve, we are able to identify the rubbery plateau, terminal relaxation time, and viscous flow region as a function of annealing time and temperatures that are well-above its glass transition. Our measurement technique and analysis provide an alternative means to measure viscoelastic properties and relaxation behavior of geometrically confined polymer films. 相似文献
117.
This study determined the extent that irradiation of fresh beef surfaces with an absorbed dose of 1 kGy electron (e-) beam irradiation might reduce the viability of mixtures of O157 and non-O157 verotoxigenic Escherichia coli (VTEC) and Salmonella. These were grouped together based on similar resistances to irradiation and inoculated on beef surfaces (outside flat and inside round, top and bottom muscle cuts), and then e-beam irradiated. Salmonella serovars were most resistant to 1 kGy treatment, showing a reduction of ≤ 1.9 log CFU/g. This treatment reduced the viability of two groups of non-O157 E. coli mixtures by ≤ 4.5 and ≤ 3.9 log CFU/g. Log reductions of ≤ 4.0 log CFU/g were observed for E. coli O157:H7 cocktails. Since under normal processing conditions the levels of these pathogens on beef carcasses would be lower than the lethality caused by the treatment used, irradiation at 1 kGy would be expected to eliminate the hazard represented by VTEC E. coli. 相似文献
118.
Postconsumer poly(ethylene terephthalate) waste bottles were glycolyzed as precursors of unsaturated polyester resin (UPR) and their montmorillonite (MMT)‐filled nanocomposites. The glycolysis product (hydroxyl‐terminated oligomers) was converted into UPR with various acid contents. These resins were miscible with styrene and could be cured with peroxide initiators to produce thermosetting unsaturated polyester (UP). Nanocomposites composed of UP matrix and organically modified clay were prepared by in situ polymerization. These were characterized for thermal and dynamic mechanical properties. Transmission electron microscopy was also used to study the morphology at different length scales and showed the nanocomposites to be compromised of a random dispersion of intercalated/exfoliated aggregates throughout the matrix. With an increase in unsaturated acid content (for a fixed content of clay), the value of storage modulus varied from 2737 to 4423 MPa. The glass‐transition temperatures of these nanocomposites ranged from 54 to 78°C, and the crosslink density varied from 3.70 × 105 to 5.72 × 105 mol/m3. The X‐ray diffraction (XRD) of modified MMT exhibited a peak that vanished completely in the polymer nanocomposites. Thus, the XRD results apparently indicated a distortion of the platy layers of nanofiller in the UP nanocomposites. The nanocomposites showed higher modulus values (2737–4423 MPa) compared to the pristine polymer (2693 MPa). From thermogravimetric analysis, all of the nanocomposites were stable up to 200°C and showed a two‐stage degradation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
119.
The crystallization, microstructure, microhardness and theoretical machinability have been investigated by DTA, XRD, SEM and Microhardness Indenter of resulting glass-ceramics. Two distinct crystallization exotherms in the DTA curve are observed and resolved. The first peak corresponds to the initial formation of potassium fluorophlogopite and the second is due to the formation of barium fluorophlogopite. The activation energy for precipitation of each crystalline phase has been evaluated, and the crystallization mechanism has been studied. DTA analyses were conducted at different heating rates and the activation energy was determined graphically from Kissinger and Ozawa equation. The average activation energy is calculated as 276 KJ/mol for the first and 366 KJ/mol for the second crystallization peak. The Avrami exponent for first and second crystallization peak temperature determined by Augis and Bennett method is found to be 3 and 3.9, respectively. The results indicate that the growth of mica is a two and three dimensional process, controlled by the crystal-glass interface reaction. The Vicker's hardness decreased steadily at intermediate heat treatment temperature with the formation of barium and potassium fluorophlogopite phase, but the decrease in hardness is more rapid at higher temperature with the development of an interconnected ‘house of cards’ microstructure. 相似文献
120.
Anish Karmakar S. Sivaprasad S. Kundu Debalay Chakrabarti 《Metallurgical and Materials Transactions A》2014,45(4):1659-1664
Ferrite-carbide and ferrite-martensite dual-phase microstructures have been produced in a low-carbon steel with different ferrite grain structures such as, uniform distribution of coarse- and very fine-ferrite grains, and bimodal distribution of ferrite grain sizes comprising of coarse grains (~12 μm) and very fine grains (<2 μm). Very fine-grained dual-phase structure offered the best combination of tensile-strength and ductility among all the samples. The above microstructures have been compared in terms of their strain-hardening rate and the mechanism of plastic deformation. 相似文献