799 research outputs found

    Urgent Need for Reduction in Greenhouse Gas Emissions in Industrial Processes: Are We Past the Tipping Point for Global Warming?

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    In a previous Guest Editorial (Piacentini and Mujumdar, 2007) and an article (Piacentini and Mujumdar, 2009), we analyzed the relation between climate change and industrial processes, mainly related to drying.Fil: Piacentini, Ruben Dario Narciso. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Mujumdar, A. S. . Minerals, Metals & Materials Technology Centre ; Singapur. Institute of Chemical Technology; Indi

    Near-field imaging and frequency tuning of a high-Q photonic crystal membrane microcavity

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    We discuss experimental studies of the interaction between a nanoscopic object and a photonic crystal membrane resonator of quality factor Q=55000. By controlled actuation of a glass fiber tip in the near-field of a photonic crystal, we constructed a complete spatio-spectral map of the resonator mode and its coupling with the fiber-tip. On the one hand, our findings demonstrate that scanning probes can profoundly influence the optical characteristics and the near-field images of photonic devices. On the other hand, we show that the introduction of a nanoscopic object provides a low-loss method for on-command tuning of a photonic crystal resonator frequency. Our results are in a very good agreement with the predictions of a combined numerical/analytical theory.Comment: 9 pages, 4 figure

    Study on Magnesium based Pyrotechnic Composition as a Priming Charge

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    A new pyrotechnic composition containing Mg/KNO3/phenolic resin has been formulated and studied in detail for its sensitivity, mechanical and thermal properties, moisture and environmental effects and performance in a closed vessel. The data generated reveal that this composition shows superior performance, better mechanical properties and less susceptibility to moisture as compared to gunpowder. In addition, performance of the composition under extreme hot (45 degree centigrade) and cold (-26 degree centigrade) environmental conditions is not affected at all. Differential thermal analyser results indicate that phenolic resin plays a vital role in reducing the ignition temperature of Mg/KNO/sub 3/ system

    Comparative study of nondescent vaginal hysterectomy and abdominal hysterectomy at tertiary care centre, Maharashtra

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    Background: Vaginal route of hysterectomy has distinct health and economic benefits in terms of less morbidity, better postoperative quality of life outcomes, reduced hospital stay and better patient satisfaction. Objectives of current study were to evaluate the appropriate route of hysterectomy (abdominal or vaginal) in terms of intra and post-operative complication, morbidity and blood loss. Methods: This prospective study was done among 100 cases of hysterectomy of which 50 patients underwent NDVH and 50 underwent abdominal hysterectomy. This study included all emergency and booked patients having Size of uterus less than 12 weeks size, adequate uterine mobility, adequate access, adenomyosis, dysfunctional uterine bleeding, chronic PID & fibroid uterus.Results: Study found statistically significantly higher number of the participants with parity 3 & 4 in both the study groups. Bulky uterus followed by 12 and 10 weeks uterus in statistically significantly higher number of the participants of both the study groups. Duration of surgery statistically significantly less in NDVH group compare to TAH group. Fibroid was the main indication of hysterectomy in both the groups. Hemorrhage was the main intra-operative complication in both the groups. Fever & respiratory tract infection was the main post-operative complications in both the groups.Conclusions: Benefits of NDVH over TAH are Cosmetic advantage as less invasive, No discomfort of abdominal incision, shorter operative time, lesser blood loss, lesser intraoperative and postoperative complications, postoperative comfort is more, lesser requirement of postoperative analgesia, early ambulation and shorter hospital stay

    Numerical Investigation of Heat Transfer Performance of Various Coiled Square Tubes for Heat Exchanger Application

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    AbstractIn heat exchanger application, working fluid inside the tubes is subjected to considerable temperature changes. In order to improve heat transfer performance, various strategies are proposed and evaluated; one of them is the application of coiled tubes. Coiled tubes have been used widely in heat exchanger application mainly due to the presence of secondary flow which enhances heat transfer considerably. This study addresses heat transfer performance of three configurations of coiled tubes with square cross-section, i.e. in-plane, helical and conical coiled tubes, subjected to large temperature difference. Their heat transfer performance is numerically evaluated and compared with that of a straight tube with identical cross-section and length. A concept of Figure of Merit (FoM) is introduced and utilized to fairly asses the heat transfer performance of the coiled tube configurations. The results indicate that FoM increase as the wall temperature increase. In addition, combination of temperature-induced buoyancy flow and curvature-induced secondary flow considerably affect the flow behavior and heat transfer performance inside the tubes

    Electro-kinetic technology as a low-cost method for dewatering food by-product

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    Increasing volumes of food waste, intense environmental awareness, and stringent legislation have imposed increased demands upon conventional food waste management. Food byproducts that were once considered to be without value are now being utilized as reusable materials, fuels, and energy in order to reduce waste. One major barrier to the valorization of food by-products is their high moisture content. This has brought about the necessity of dewatering food waste for any potential re-use for certain disposal options. A laboratory system for experimentally characterizing electro-kinetic dewatering of food by-products was evaluated. The bench scale system, which is an augmented filter press, was used to investigate the dewatering at constant voltage. Five food by-products (brewer’s spent grain, cauliflower trimmings, mango peel, orange peel, and melon peel) were studied. The results indicated that electro-kinetic dewatering combined with mechanical dewatering can reduce the percentage of moisture from 78% to 71% for brewer’s spent grain, from 77% to 68% for orange peel, from 80% to 73% for mango peel, from 91% to 74% for melon peel, and from 92% to 80% for cauliflower trimmings. The total moisture reduction showed a correlation with electrical conductivity (R2¼0.89). The energy consumption of every sample was evaluated and was found to be up to 60 times more economical compared to thermal processing

    Conjunctive use modeling for multicrop irrigation

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    A mathematical model is developed to arrive at an optimal conjunctive use policy for irrigation of multiple crops in a reservoir-canal–aquifer system. The integration of the reservoir operation for canal release, ground water pumping and crop water allocations during different periods of crop season (intraseasonal periods) is achieved through the objective of maximizing the sum of relative yields of crops over a year considering three sets of constraints: mass balance at the reservoir, soil moisture balance for individual crops, and governing equations for ground water flow. The conjunctive use model is formulated with these constraints linked together by appropriate additional constraints as a deterministic linear programming model. A two-dimensional isotropic, homogeneous unconfined aquifer is considered for modeling. The aquifer response is modeled through the use of a finite element ground water model. A conjunctive use policy is defined by specifying the ratio of the annual allocation of surface water to that of ground water pumping at the crop level for the entire irrigated area. A conjunctive use policy is termed stable when the policy results in a negligible change in the ground water storage over a normal year. The applicability of the model is demonstrated through a case study of an existing reservoir command area in Chitradurga district, Karnataka State, India
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