267 research outputs found

    Understanding Standpipe Hydrodynamics Using Electrical Capacitance Tomography

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    Standpipes are often the bottleneck in a circulating fluidized bed processes. Understanding the pressure build and dissipation in a standpipe is critical in designing and operating a standpipe that can meet production needs. However, this critical component of a circulating fluidized bed (CFB) is often neglected in the design process which usually results in an underperforming unit operation. In an effort to better design new standpipe and to better optimize existing ones, electrical capacitance tomography (ECT) was evaluated in a 7-inch (18-cm) diameter standpipe to understand the gas-solid hydrodynamics in a standpipe with respect to circulation rates and aeration strategies

    Study on investment pattern and organizational structure of Super markets in India-An empirical evidence of Karnataka

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    Retail business has shown tremendous growth in the World in the recent past. In India, the organized food retailing sector is on the verge of a boom and expected to undergo further change with prospective new domestic and global foreign entrants and the takeover or exit of some existing participants. Among the Indian states, Karnataka is far more forward looking as far as food retailing is concerned. Therefore, it is imperative to study the entire business aspects of organized food retailing. The study indicated that majority of the organized supermarkets has multi outlets operating under the single management. The un-organized supermarkets were formed by the big local and conventional store owners. The average area of the supermarket outlets in Bangalore (4333 Sqft) and Mysore (3133 Sqft) is more compared to other cities of Karnataka like Mangalore (2833 Sqft), Hubli-Dharwad (1833 Sqft) and Belgaum (1200 Sqft) as the supermarkets in these cities were recently converted from the conventional ‘kirana’ format. The average total fixed cost per outlet is Rs. 78.42 lakh for the state as a whole and total costs required to establish a supermarket in the Karnataka is Rs. 261.33 lakh. The investments in establishment, modernization and expansion are capital intensive in supermarkets. In all the supermarkets, the liquid assets to total assets ratio indicated organized supermarkets seems to better than other unorganized supermarkets in terms of assets liquid ratio. Further, organized supermarkets/supermarkets in multi outlet (chain of supermarkets) firms/companies followed line, line and staff, and the functional categories of organizational structures. Whereas line organization was commonly followed in un-organized supermarkets and are family owned. Key words: Retail, Super market, Multi-outlet, Organization, Investment, Profi

    PARTICLE CLUSTERS IN FLUIDIZED BEDS

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    Accurately predicting the entrainment rate is important in designing a commercial fluidized bed. However, most correlations fall short in providing an accurate prediction of the entrainment rate. Many correlations assume that smaller particles have a higher entrainment rate than larger particles; but, this is often not the case. Smaller particles can, and often do, have lower effective entrainment rates than larger particles. This has been presumed from several different experiments. In one case, the entrainment rate of FCC catalyst fines was measured at different fluidized bed heights and found that higher entrainment fluxes were observed at lower bed heights (i.e., higher disengaging heights). In a second case, it was found in a batch entrainment test that with an initial high concentration the fines level in the entrainment flux was very low. As the fines were gradually elutriated away, the entrainment flux increased dramatically. Following a dramatic increase to a maximum, the entrainment flux then exhibited the classical batch exponential decay as the fines were elutriated from the fluidized bed. Recently, high speed video of particles in a fluidized bed freeboard was able to image and track large clusters of particles in the range of 200 microns to 1000 microns when the bed material had a mean particle size of only 25 microns. All of these findings suggests that fine particles in many materials are clumping or clustering. This increases their effective particle diameter which reduces the entrainment rate. The clumps appear to be formed in the fluidized bed, and are ejected into the freeboard. High-speed videos obtained using observations through a borescope inserted into a fluidized bed at PSRI have confirmed the presence of clusters in fluidized beds. Such a phenomenon has many implications regarding how entrainment may be influenced by fines level, bed height, baffles, jet velocity at the distributor, etc

    Tolerance in chickpea to Meloidogyne javanica

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    Quarante-sept cultivars de pois chiche ont été testés pour leur résistance ou leur tolérance envers #Meloidogyne javanica en notant leur croissance dans des sols infestés et des sols sans nématodes. En se fondant sur le nombre de galles, la taille de celles-ci, la surface des racines occupée par les galles et le nombre de masses d'oeufs produites, tous les cultivars paraissent sensibles. L'infestation par le nématode provoque un nanisme, un jaunissement, un dessèchement précoce et une chute des feuilles. Une analyse de régression démontre que la hauteur des plants, le poids des pieds, celui des racines et celui des gousses diminuent lorsque l'infestation augmente. La floraison de deux cultivars tardifs, Pant G 114 et Phule G 1, est retardée dans les sols infestés tandis que chez les cultivars précoces cette floraison est soit avancée soit indifférente à l'infestation par le nématode. Le rapport du poids des racines dans les sols infestés et non infestés - seuil de tolérance - démontre que les cultivars Pant G 114, Phule G 1, GNG 146 et Annigini n'ont qu'un faible niveau de tolérance à #M. javanica. Le niveau de tolérance des cultivars Bheema, N 31 et N 39 est d'environ 4,0 oeufs/gr-1 de sol. Dans un sol infesté, l'absorption de calcium par le cultivar tolérant N 31 est plus élevée que par le cultivar non tolérant Phule G 1. Dans un champ infesté par une population mixte de #M. javanica et #M. incognita, les performances des cultivars tolérants prometteurs N 31, N 59, ICCC 42 et de la lignée de croisement ICCV 90043 se sont révélées meilleures que celles des autres génotypes de pois chiche. (Résumé d'auteur

    PARTICLE ATTRITION MEASUREMENTS USING A JET CUP

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    Particle attrition is usually detrimental as it negatively affects product quality and process cost. Thus, it is important to know how particles attrit under relevant operating conditions. Small jet cup attrition test devices (such as the Davison Jet Cup) are typically used to measure relative particle attrition for fluidized beds and risers. Ideally, the attrition rates measured in these laboratory units provide a relative indication of how the materials will behave in the commercial unit. Most jet cup devices have a cylindrical configuration. However, Particulate Solid Research, Inc. (PSRI) has found that a cylindrical jet cup attrition measurement may not be effective in providing accurate attrition rankings. Attrition index rankings from a cylindrical jet cup and a 0.3-meter (12-inch) diameter, pilot-plant fluidized bed unit did not agree with each other. It was subsequently found in cold flow studies at PSRI in Plexiglas™ jet cup models which showed that many of the solids were nearly stagnant, even at high inlet jet velocities. Approximately 30 to 50% of the particle sample in a cylindrical jet cup was not in motion and was not exposed to the solid stresses needed for accurate particle attrition measurements. Computational Fluid Dynamics (CFD) results confirmed this finding. As a result, it is unlikely that relevant attrition rankings can be reliably determined from cylindrical jet cup studies because a significant portion of the particle sample is not exposed to sufficient solid stresses to cause attrition. Only by insuring that the entire sample is under a similar amount of stress can attrition be accurately linked to inlet jet velocity and directly compared with different materials. This paper discusses the development of a conical jet cup device that allows all of the sample particles to experience similar solids stresses. The rankings of the attrition indices from the conical jet cup were found to correspond to the rankings observed in pilot-plant attrition tests. The agreement in rankings obtained with the new conical jet cup was not observed with the traditional cylindrical jet cup

    Expression of the legume symbiotic lectin genes psl and gs52 promotes rhizobial colonization of roots in rice

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    Transgenic rice (Oryza sativa L. cv. Murasaki) carrying genes encoding pea (Pisum sativum) lectin (PSL) or wild-soybean (Glycine soja) lectin-nucleotide phosphohydrolase (GS52) were inoculated with Rhizobium leguminosarum bv. viciae or Bradyrhizobium japonicum USDA110, respectively, as well as with Rhizobium sp. NGR234, and root colonization was assessed in comparison to comparably inoculated control plants. The data showed that expression of PSL and GS52 significantly promoted rhizobial colonization of root epidermal cells including root hairs in rice. In addition, in the case of R. leguminosarum bv. viciae and B. japonicum USDA110 colonization of the psl and gs52 transgenic rice plants, respectively, the bacterial cells were found to preferentially home towards and aggregate maximally at the root hair tip regions rather than on the root hair "stalks". The above data suggest that the lectins PSL and GS52, which participate in rhizobial recognition by root epidermal cells in pea and soybean, respectively, are also able to facilitate rhizobial attachment and colonization of the epidermal cells in rice roots. Moreover, aggregation of R. leguminosarum bv. viciae and B. japonicum USDA110 cells preferentially at root hair tip regions suggest that similar to legumes, the PSL and GS52 lectins are targeted to the root hair tips in transgenic rice, enabling higher bacterial attachment/colonization at the tip region. Rhizobial colonization at root hair tips in the psl and gs52 rice plants frequently led to the localized dissolution of the cell wall creating perforations at the tip region. It is likely that the presence of lectins, such as PSL and GS52 leads to structural modifications in cell wall organization of the root hair/epidermal cells, making them prone to localized dissolution by the hydrolytic activity of compatible rhizobia to permit invasion of the root cells. © 2005 Elsevier Ireland Ltd. All rights reserved

    Pigeonpea - A unique jewel in rainfed cropping systems

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    Pigeonpea is a crop for rainfed environments endowed with several features to thrive harsh climate. It adapts well in sole crop and inter cropped conditions (with cereals, millets, oils seeds and pulses) by enhancing the system productivity and net income to the small and marginal farmers across the globe. The range of maturity duration in the crop allows it to grow in diversified cropping systems and patterns in varied ecoregions of the world. Development of cytoplasmic male sterility based hybrids provided an opportunity for enhancing the yields under marginal environments. With recent interventions in addressing the photo sensitivity and maturity have led to evolving super early varieties with less than 100 days duration, provided a scope for horizontal expansion of the crop in different agro ecological systems
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