422 research outputs found

    Economics of operation of 38' G.R.P. fishing vessels issued by the A.D.B. Fisheries Project: a case study

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    The author gives a financial and economic valuation of the operation of vessels in the 38 foot GRP class. He discusses particularly the materials and methods of fishing they use, species composition of their catches, their rate of return, break-even analysis, financial and social analysis

    Fishing gear and methods of the river Brahmaputra in Assam

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    Potentially the inland fishery resources of the country are of very high order. But the present level of their exploitation is far from optimum, mainly because of the inadequacies of the existing fishing gear and methods. There is vast scope for increasing the fish production from inland waters by improving the existing gear and methods. This would require a thorough study of the fishing gear and methods in vogue, of which very little is known at present. In the present communication the authors discuss the fishing gear and methods of the river Brahmaputra, in Assam, based on a survey carried out by them during January-February 1964. The survey covers a 640 km stretch of the Brahmaputra River, its important tributaries and connected bheels, from Dhubri to Dibrugarh. As a result of the survey about 19 types of fishing nets, which could be grouped into eight classes, were identified. The salient technological features of the gears and their methods of operation are discussed class-wise. The characteristics of the individual types are shown in tables. The materials used for gear and gear accessories, are briefly discussed. The classification and relative importance of different types of gear are examined. Besides, the influence of the ecological and topographical features of the river on the development of different types of fishing gears, is also discussed

    Effect of chemical reaction on unsteady MHD free convective two immiscible fluids flow

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    The effect of chemical reaction on unsteady MHD free convective two immiscible fluids flow has been studied. Approximate analytical solutions to the governing equations are found for the coupled and linear differential equations using regular perturbation method. Graphs depicting the effect of chemical reaction parameter and others flow parameters on velocity, temperature and concentration profiles are obtained anddiscussed accordingly. The effect of flow parameters on the coefficient of skin friction, Nusselt number and Sherwood number are also tabulated and discussed appropriately. It was observed that the increase in chemical reaction coefficient/parameter suppresses both velocity and concentration profiles.Keywords: Chemical Reaction, MHD, Convective, Immiscible, Unstead

    Performance and nutrients digestibility of piglets fed ditary detoxified balanites augyptiaca friuts

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    A feeding trial was conducted to assess the effect of dietary detoxified Nigerian Balanites aegyptiaca fruits on performance and nutrients digestibility of weanling pigs. Twenty pigs weighing averagely 4.5 ± 0.85kg were used for the experiment which lasted for one month. The pigs were randomly allocated to the five dietary treatments in a completely randomized design. Five diets made of a corn-soy control diet and four others to which 20% of boiled, roasted, boiled and roasted, boiled and fermented respectively were used. Feed consumption and weight gain of pigs maintained on the Balanites based diets were comparable with the conventional diet (p > 0.05). However, efficiency of feed utilization on the Balanites containing diets was inferior to that on the control diet (p 0.05) but protein and fatdigestibility were significantly influenced by dietary Balanites (p 0.05). Nitrogen consumption using indices of protein intake, fecal nitrogen output, daily retainednitrogen and nitrogen retention coefficient were not significantly different from values obtained on the control diet (p > 0.05). It was therefore concluded that Balanites aegyptiaca fruits, when detoxified by any of the traditional methods adopted, could be incorporated in diets for livestock even up to 70% inclusion level without deleterious effects on animal consuming the feed

    Biotechnology as a Change Agent for National Development: Review in The Gambia

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    Biotechnology is an important tool which can ensure the production of crop that will have longer shelf live, drought resistant, high saline tolerance, ability to withstand adverse conditions among others. The Gambia among the low-income West African countries, where agriculture is practiced by two-thirds of its citizens and couple with global population which is now around 7 billion predicted to rise to 9 billion by 2050, the Gambian government really needs to act fast and positively in welcoming genetically modified crops if it’s to be able to feed its population now roughly around 2 million people. Application of Biotechnology in crop and animal farming through genetic engineering has led to the development of crops with desirable characteristics such as crop varieties that cope better with drought and salinity, crops that more resistant to pest and diseases and crops that use nutrients more efficiently. This can help transform The Gambia into a country with a robust agriculture capable of not feeding the nation but also generating substantial foreign exchange. Through Agricultural biotechnology, this looming crisis can be averted  eradicating malnutrition by ensuring food self-sufficiency through the production of resistant crops to pests and diseases, having longer shelf-lives, higher nutritional content and palatability, higher yields and early maturity period, tolerant to adverse weather and soil conditions. Achieving food sufficiency which is a direct consequence of a flourishing agricultural sector will facilitate a shift from other natural resources as a source of foreign exchange thus promoting economic diversity through agriculture

    Seasonal Variation of Atmospheric Aerosols over Prominent Hotspot Regions in South India by Employing MODIS Data

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    Mounting the amount of aerosols in the atmosphere is a subject of deep concern all over the globe. This elevated level of aerosol concentrations has proven direct impact on the radiative forcing (Gadhavi and Jayaraman A, 2004) and subsequent climate change. Thus it becomes imperative to study the inter-annual and seasonal variations of aerosols with the aid of remote sensing method by employing MODIS data. This paper pertains to the study of seasonal variations of Aerosol Optical Depths over three different locations which are lying along the same latitude in South India. The five year (2005-2009) observation is presented and it reveals that aerosol abundance has strong dependence on the geography, environment and local climate at a specific region. The variation of aerosol abundance is found to be higher at the coastal region than the region surrounded by land mass

    Multifunctional performance of carbon nanotubes and graphene nanoplatelets reinforced PEEK composites enabled via FFF additive manufacturing

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    The study is focused on multifunctional performance of carbon nanotubes (CNT) and Graphene nanoplatelets (GNP) reinforced PEEK composites enabled via fused filament fabrication (FFF) additive manufacturing (AM) utilizing in-house nanoengineered filaments. Thermo-physical, mechanical and wear characteristics of electro-conductive PEEK nanocomposites are reported. The coefficient of thermal expansion (CTE) is found to decrease by 26% and 18% with the incorporation of 5 wt% GNP and 3 wt% CNT into PEEK polymer, respectively. The decrease in CTE provides better dimensional stability to resulting nanocomposite structures. Due to uniform dispersion of CNT and GNP in the PEEK matrix, the crystallization temperature and degree of crystallinity are both increased. The 3D printed PEEK nanocomposites reveal interfacial voids between the beads and intra-bead pores and thus exhibit lower density compared to that of the 3D printed neat PEEK. Young's and storage moduli are found to increase by 20% and 66% for 3 wt% CNT loading and by 23% and 72% for 5 wt% GNP loading respectively. However, the PEEK nanocomposites exhibit similar tensile strength to that of neat PEEK. The coefficient of friction obtained from fretting wear tests is found to decrease by 67% and 56% for 1 wt% CNT and 3 wt% GNP loaded PEEK nanocomposites, respectively and the decrease is attributed to reduced hardness and increased porosity. Multifunctional performance of carbon nanostructures reinforced AM-enabled PEEK composites demonstrated here makes them suitable for a range of applications such as orthopedics, oil and gas, automotive, electronics and space

    Effect of microwave radiation on seed mortality of rubber vine (Cryptostegia grandiflora R.Br.), parthenium (Parthenium hysterophorous L.) and bellyache bush (Jatropha gossypiifolia L.)

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    A trial was undertaken to evaluate the effect of microwaves on seed mortality of three weed species. Seeds of rubber vine (Cryptostegia grandiflora R.Br.), parthenium (Parthenium hysterophorous L.) and bellyache bush (Jatropha gossypiifolia L.) were buried at six depths (0, 2.5, 5, 10, 20 and 40 cm) in coarse sand maintained at one of two moisture levels, oven dry or wet (field capacity), and then subjected to one of five microwave radiation durations of (0, 2, 4, 8 and 16 min). Significant interactions between soil moisture level, microwave radiation duration, seed burial depth and species were detected for mortality of seeds of all three species. Maximum seed mortality of rubber vine (88%), parthenium (67%) and bellyache bush (94%) occurred in wet soil irradiated for 16 min. Maximum seed mortality of rubber vine and bellyache bush seeds occurred in seeds buried at 2.5 cm depth whereas that of parthenium occurred in seeds buried at 10 cm depth. Maximum soil temperatures of 114.1 and 87.5°C in dry and wet soil respectively occurred at 2.5 cm depth following 16 min irradiation. Irrespective of the greater soil temperatures recorded in dry soil, irradiating seeds in wet soil generally increased seed mortality 2.9-fold compared with dry soil. Moisture content of wet soil averaged 5.7% compared with 0.1% for dry soil. Results suggest that microwave radiation has the potential to kill seeds located in the soil seed bank. However, many factors, including weed species susceptibility, determine the effectiveness of microwave radiation on buried seeds. Microwave radiation may be an alternative to conventional methods at rapidly depleting soil seed banks in the field, particularly in relatively wet soils that contain long lived weed seeds

    Surface Instability in Windblown Sand

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    We investigate the formation of ripples on the surface of windblown sand based on the one-dimensional model of Nishimori and Ouchi [Phys. Rev. Lett. 71, 197 (1993)], which contains the processes of saltation and grain relaxation. We carry out a nonlinear analysis to determine the propagation speed of the restabilized ripple patterns, and the amplitudes and phases of their first, second, and third harmonics. The agreement between the theory and our numerical simulations is excellent near the onset of instability. We also determine the Eckhaus boundary, outside which the steady ripple patterns are unstable.Comment: 23 pages, 8 figure
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