Estimation of Heat Losses from Modified Cavity Mono-tube Boiler Receiver of Solar Parabolic Dish for Steam Generation

AbstractIn this article, a 3-D numerical investigation is carried out to estimate heat losses from solar parabolic dish with modified cavity receiver used for three different steam generation conditions viz. sub-cooled, saturated, superheated steam. The effect of inclination of the receiver, operating temperature, emissivity of the cavity cover, insulation thickness on the total heat loss from the modified cavity receiver has been investigated. The variable wall temperature boundary conditions and insulation thicknesses are applied to match the actual conditions. The results show that the convection heat losses are higher at 0° inclination and found to be 400 to 500W for superheated steam generation; 300 to 425W for saturated steam generation and 50 to 125W for sub-cooled steam. The radiation heat losses remain constant for all inclinations and vary with the temperature. Nusselt number correlations have been proposed based on the numerical analysis. The present model can be used to predict total heat losses from the modified cavity receiver under all conditions more accurately

On the arrival time, waiting time to unload, unloading time and waiting time for departure for purse seiners at Mangalore landing centre

Fifty four purse-seine boats at Mangalore landing centre were observed during different stages of unloading fish catch. It was found that a boat takes 75% of the berthing time to unload an average quantity of 2.4 tons of fish. Further, unloading period and catch were found to be directly related where it was estimated that 5 to 7 minutes are spent in unloading about half a ton of fish to a nearby tempo by employing 9 ± 2 laborers

Higher education, high-impact research, and world university rankings: A case of India and comparison with China

AbstractTo date, this paper is probably the first to compare Indian and Chinese universities on educational performance metrics such as high-impact research and world university rankings. The study, therefore, examines the current state of higher education, high-impact research metrics, and world university rankings in an emerging market of India. First, we present an overview of the higher education system, government schemes for academic research, and related educational statistics. Second, we compare India and China on various academic-research metrics (citable documents, number of citations, cites per document, and H-index in three categories), and world university rankings. Special attention is devoted to revealing the progress of management research metrics, business school accreditations and rankings, and abstracting and indexing of publishing journals. Last, we discuss several challenges in university education and recommend policy guidelines pertaining to research funding, collaborative research projects, and research assessment council for imparting quality academic practices and standards in a higher education environment. Our exploratory analysis indicates that for citable documents in the ‘all subjects’ category, the United States is ranked first, followed by China in second, the United Kingdom in third, and India in ninth. Overall, world university rankings and research metrics of Indian universities are found to be far behind those of Chinese universities

Thermal Performance of a Solar Concentrating Photovoltaic Module with Spiral Mini Channel Heat Sink

ICP 2015: International Conference on Polygeneration, Chennai, India, 18-20 February 2015Concentrating Photovoltaic (CPV) power generation is one of the attractive choices for efficient utilization of solar energy due to its high cogeneration efficiency. The increase in temperature of solar CPV cell significantly reduces the performance. The efficiency of a CPV system can be improved by introducing effective thermal management or cooling system. In this paper, a new spiral mini channel heat sink with rectangular cross section is developed and its performance is numerically analysed using commercial CFD software ANSYS 14. The mini-channels provided high heat transfer over cell surface area and resulted in lower pressure drop. The coolant outlet temperature rise across the mini-channel is estimated as 343K in CPV module of 300 X 300 mm2 and with a pressure drop of 8.043 k Pa at a flow rate of 0.16 liter/s. Based on numerical simulations, it is found that the optimum configuration of micro-channel with 4mm width and height of 20mm, having higher figure of merit.Department of Science and Technology (DST), Government of Indi

Reproductive biology of the blue spot mullet Valamugil seheli (Forskal) from Mangalore Region, southwest coast of India

The blue spot mullet Valamugil seheli spawns once a year between August and February with peak spawning during October - November. Males attain maturity at 250.5 mm and females at 256.5 mm total length. Males outnumbered females in the commercial catches, although the sex-ratio (M:F=1:0.90) in the population showed no significant deviation. The fecundity of this species varied from 108378 to 910350 eggs with an average of 327944. Linear relationships were found between fish length, gonad weight and fecundity; and between fish length, fish weight and ovary weight

Heat Transfer Modeling and Analysis of Solar Thermo-chemical Reactor for Hydrogen Production from Water

AbstractA solar thermo-chemical reactor is modeled and analyzed for the solar thermal dissociation of zinc oxide into zinc and oxygen involved in the thermo-chemical cycle for hydrogen production. The reactor consists of a cavity surrounded by a rotating insulation layer made of alumina. The granular zinc oxide particles are fed into the cavity and are directly exposed to the solar radiation entering the cavity through a quartz window. A three dimensional numerical model coupling the multiphase particle dynamics in gravitational field, multiphase heat transfer, k-ɛ turbulence model, discrete ordinates radiation model, Arrhenius reaction rate model is developed. The cavity temperature and oxygen molar flow rate at the outlet of the reactor which is the indicator of the reaction rate has been validated with a 10kW reactor prototype. An energy balance study of thermal performance parameters including the various losses occurring from the reactor and efficiency is also done. The major losses were contributed by re-radiation (46%) and sensible heating of reactor components (35.5%), while the minor losses were contributed by convection by argon (1%) and conduction through insulation (2%).The thermal efficiency of the reactor is calculated to be 15.5%

Diel feeding patterns, rate of gastric evacuation and foods of Indian sandwhiting, Sillago sihama in Mulki estuary, west coast of India

Diel feeding chronology of sandwhiting, Sillago sihama was examined from stomach collections taken during the months of April, July and December'99 in Mulki estuary along Dakshina Kannada coast, India. Significant differences in mean stomach content weight were found between several consecutive 3 hour periods with peak fullness occurring in early morning and evening hours. The rate of gastric evacuation of natural food (crustacea, polychaetes and fish) was measured in the field was best described by an exponential model, with an estimated evacuation time of 8.0 h at a temperature of 28.5 ± 1.2°C. Stomach content analysis indicated that this species is a carnivore on a wide range of benthic, epibenthic and planktonic prey. The principal food items of S. sihama were crustaceans, polychaetes and fish. Fishes less than 100 mm TL preferred mainly crustaceans while larger ones depends on polychaetes, crustaceans and fish. The feeding activity of S. sihama was influenced by tidal cycle

Hybrid Low Complex near Optimal Detector for Spatial Modulation

In our previous work maximum throughput in multi stream MIMO is analyzed by overcoming the inter antenna interference. To mitigate the Inter antenna interference spatial modulation can be used. Spatial Modulation(SM) aided MIMO systems are the emerging MIMO systems which are low complex and energy efficient. These systems additionally use spatial dimensions for transmitting information. In this paper a low complex detector based on matched filter is proposed for spatial modulation to achieve near maximum likelihood performance while avoiding exhaustive ML search since MF based detector exhibits a considerable reduced complexity since activated transmitting antenna and modulated amplitude phase modulation constellation are estimated separately. Simulation results show the performance of the proposed method with optimal ML detector, MRC and conventional matched filter methods

Primary vaginal Ewing’s sarcoma/primitive neuroectodermal tumour: diagnostic and treatment challenges

Extra osseous Ewing’s sarcoma/primitive neuroectodermal tumour (PNET) of the genital tract of women is scarcely\ud described in the literature and involvement of the vagina is even rarer with a very few cases reported so far. We present\ud 50-year-old-woman who presented with a vaginal mass that was diagnosed to be a malignant round cell tumour which\ud later was confirmed to be primary vaginal Ewing’s sarcoma/ PNET on light microscopy and immunohistochemical\ud staining. She was then treated with induction chemotherapy followed by local radiotherapy and further maintenance\ud chemotherapy. This rare case of primary vaginal Ewing’s sarcoma/PNET emphasizes the need for combining\ud morphological features with immunohistochemistry with a panel of antibodies in establishing the diagnosis of Ewing’s\ud sarcoma/PNET at an uncommon site. Further, the case also highlights the use of induction chemotherapy followed by\ud radiation therapy and subsequent maintenance chemotherapy as a treatment modality

Conjugate Refractive-Reflective Homogeniser in a 500x Cassegrain Concentrator: Design and Limits

This is the author accepted manuscript. The final version is available from IET via the DOI in this recordThere is another ORE record for this publication: http://hdl.handle.net/10871/19792In this study, we present the conjugate refractive reflective homogeniser (CRRH) to be used in a 500× Cassegrain photovoltaic concentrator. The CRRH is a dielectric crossed v-trough lined with a reflective film whilst maintaining an air gap between them. This air gap between the two surfaces helps in trapping the scattered light from the refractive geometry and ensures both total internal reflection and standard reflection of the escaped rays. A 10-42% drop in optical efficiency has been shown to occur due to varying the surface roughness of the homogeniser in these ray trace simulations for the Cassegrain setup. The CRRH increased the overall optical efficiency by a maximum of 7.75% in comparison with that of a standard refractive homogeniser simulated within the same concentrator system. The acceptance angle and flux distribution of these homogenisers was also investigated. The simple shape of the CRRH ensures easy manufacturing and produces a relatively uniform irradiance distribution on the receiver. The theoretical benefit of the CRRH is also validated via practical measurements. Further research is required but a 6.7% power increase was measured under a 1000 W/m2 solar simulator at normal incidence for the experimental test.Department of Science and Technology (DST), IndiaEngineering and Physical Sciences Research Council (EPSRC