Numerical investigation on the performance of the helical and conical coil heat exchanger configuration in the dynamic mode of heat extraction

. Owing to the high heat transfer performance, compact design and large surface area per unit volume, the curved and helical circular tubes have many applications such as heating, refrigeration, air conditioning, steam generation, heat extraction etc. One of the ways to improve the performance of water heating systems is to enhance the performance of immersed heat exchanger. In solar heating systems, immersed heat exchangers of curved shape are used to charge and discharge sensible heat water storage tanks. Effect of arrangement and position of the tubes, geometry of coil, configuration, shape, flow rate, type of working fluid, Reynolds number associated with flow, and inlet temperature to coil, on the performance of storage systems have been studied in the literature. Rate of discharge, heat transfer coefficient, effectiveness of heat exchanger, heat transfer rate, discharging efficiency and increment in temperature of outlet fluid are the standard performance parameters to evaluate the heat transfer and fluid flow phenomenon in the curved tubes. Heat transfer characteristics are investigated and analyzed for one helical and two conical coil (conical and inverted conical) configurations using a three-dimensional unsteady numerical model. The numerical model is validated against reported experimental result and a good agreement is found. For the same length of the coil, the inverted conical configuration presents more heat transfer surface area to the incoming hot fluid entering the thermal energy storage tank, as compared to conical coil and helical coil configurations, leading to higher extraction of thermal energy. Based on the performance parameters, inverted conical coil experiences enhanced heat transfer, high overall heat transfer coefficient and better effectiveness of heat exchanger as compared to helical and conical coil configurations

Free fatty acids regulating action of Capparis decidua fruit on dyslipidemia in rats

Capparis decidua belongs to family Capparidaceae in wastelands of India. The study aim was to determine the role of C. decidua fruits on the free fatty acids (FFA) profile in fat-rich diet (FRD) dyslipidemic rats. The methanolic extract of edible fruit of C. decidua (CD) was given orally to obese dyslipidemic rats at the dose of 125 mg/kg and 250 mg/kg for consecutive 28 days. CD treatment in FRD rats significantly restricts the body weight gains. Blood lipid profile was altered dose dependently and significantly after 4-week treatment with CD to FRD. rats. It significantly (p<0.05) enhanced serum FFA especially, g-linolinate, a-linolinate, arachidonate, ecosapentaenoate, docosapentaenoate and docosahexaenoate. Moreover, w3-PUFA content was also enhanced (50.3% and 78.8%) in the serum of CD treated animals, whereas MUFA was lowered (31.1% and 40%). Therefore, Capparis decidua fruit has a promising role on dyslipidemia and obesity and has the capabilities to regulate beneficial free fatty acids.

Thermochemical Energy Storage Using Radial Flow Annular Reactor for Attaining Lower Pressure Drop

The auxiliary power required in the form of electrical energy for blowing the air through the packed bed reactor is an important consideration since it depends on various design parameters of the system. A radial flow annular reactor configuration is proposed in the present study. It shows a 65%-80% reduction in the flow work requirement. The parameters, such as the flow direction and flow rate, need to be optimized for better performance and to ensure lesser flow work requirements

SS 433: Results of a Recent Multi-wavelength Campaign

We conducted a multi-wavelength campaign in September-October, 2002, to observe SS 433. We used 45 meter sized 30 dishes of Giant Meter Radio Telescope (GMRT) for radio observation, 1.2 meter Physical Research Laboratory Infra-red telescope at Mt Abu for IR, 1 meter Telescope at the State Observatory, Nainital for Optical photometry, 2.3 meter optical telescope at the Vainu Bappu observatory for spectrum and Rossi X-ray Timing Explorer (RXTE) Target of Opportunity (TOO) observation for X-ray observations. We find sharp variations in intensity in time-scales of a few minutes in X-rays, IR and radio wavelengths. Differential photometry at the IR observation clearly indicated significant intrinsic variations in short time scales of minutes throughout the campaign. Combining results of these wavelengths, we find a signature of delay of about two days between IR and Radio. The X-ray spectrum yielded double Fe line profiles which corresponded to red and blue components of the relativistic jet. We also present the broadband spectrum averaged over the campaign duration.Comment: 17 pages 10 figures MNRAS (submitted

Free fatty acids regulating action of Capparis decidua fruit on dyslipidemia in rats

Capparis decidua belongs to family Capparidaceae in wastelands of India. The study aim was to determine the role of C. decidua fruits on the free fatty acids (FFA) profile in fat-rich diet (FRD) dyslipidemic rats. The methanolic extract of edible fruit of C. decidua (CD) was given orally to obese dyslipidemic rats at the dose of 125 mg/kg and 250 mg/kg for consecutive 28 days. CD treatment in FRD rats significantly restricts the body weight gains. Blood lipid profile was altered dose dependently and significantly after 4-week treatment with CD to FRD. rats. It significantly (p<0.05) enhanced serum FFA especially, -linolinate, -linolinate, arachidonate, ecosapentaenoate, docosapentaenoate and docosahexaenoate. Moreover, 3-PUFA content was also enhanced (50.3% and 78.8%) in the serum of CD treated animals, whereas MUFA was lowered (31.1% and 40%). Therefore, Capparis decidua fruit has a promising role on dyslipidemia and obesity and has the capabilities to regulate beneficial free fatty acids

Free fatty acids regulating action of Capparis decidua fruit on dyslipidemia in rats

Capparis decidua belongs to family Capparidaceae in wastelands of India. The study aim was to determine the role of C. decidua fruits on the free fatty acids (FFA) profile in fat-rich diet (FRD) dyslipidemic rats. The methanolic extract of edible fruit of C. decidua (CD) was given orally to obese dyslipidemic rats at the dose of 125 mg/kg and 250 mg/kg for consecutive 28 days. CD treatment in FRD rats significantly restricts the body weight gains. Blood lipid profile was altered dose dependently and significantly after 4-week treatment with CD to FRD. rats. It significantly (p<0.05) enhanced serum FFA especially, -linolinate, -linolinate, arachidonate, ecosapentaenoate, docosapentaenoate and docosahexaenoate. Moreover, 3-PUFA content was also enhanced (50.3% and 78.8%) in the serum of CD treated animals, whereas MUFA was lowered (31.1% and 40%). Therefore, Capparis decidua fruit has a promising role on dyslipidemia and obesity and has the capabilities to regulate beneficial free fatty acids