CFD modelling of three-phase fluidized bed with low density solid particles

Three-phase fluidization is defined as an operation in which a bed of solid particles is suspended in gas and liquid media due to net drag force of the gas and/or liquid flowing opposite to the net gravitational force (or buoyancy force) on the particles. Such an operation generates considerable, intimate contact among the gas, liquid and the solid in the system and provides substantial advantages for application in physical, chemical or biochemical processing involving gas, liquid and solid phases. Among all the types of three-phase fluidized beds, three-phase concurrent gas-liquid-solid fluidized beds are used in a wide range of applications including hydro-treating and conversation of heavy petroleum and synthetic crude, coal liquefaction, methanol production, sand filter cleaning, electrolytic timing, conversion of glucose to ethanol, aerobic waste water treatment, and various other hydrogenation and oxidation reactions. The recent fluidized bed bioreactors are superior in performance due to immobilization of cells on solid particles reducing the time of treatment, volume of reactor is extremely small, lack of clogging of bio-mass and removal of pollutant like phenol even at lower concentrations. In the fluidized bed system used in waste water treatment, low density solid matrix is used to immobilize the microbes as the system operates at low water and air velocities to avoid transportation of the particles from the bed. Hydrodynamics study of three-phase fluidized bed with low density particles are rarely seen in literature although a tremendous work is seen for moderate or high density solid particles. In the present work, the computational studies have been carried out on two dimensional fluidized beds to characterize there hydrodynamic behavior. Air, water and low density solid particles have been used as the gas, liquid and solid phase to analyze the system behaviors

Hybrid Software Reliability Model for Big Fault Data and Selection of Best Optimizer Using an Estimation Accuracy Function

Software reliability analysis has come to the forefront of academia as software applications have grown in size and complexity. Traditionally, methods have focused on minimizing coding errors to guarantee analytic tractability. This causes the estimations to be overly optimistic when using these models. However, it is important to take into account non-software factors, such as human error and hardware failure, in addition to software faults to get reliable estimations. In this research, we examine how big data systems' peculiarities and the need for specialized hardware led to the creation of a hybrid model. We used statistical and soft computing approaches to determine values for the model's parameters, and we explored five criteria values in an effort to identify the most useful method of parameter evaluation for big data systems. For this purpose, we conduct a case study analysis of software failure data from four actual projects. In order to do a comparison, we used the precision of the estimation function for the results. Particle swarm optimization was shown to be the most effective optimization method for the hybrid model constructed with the use of large-scale fault data

Organizational Commitment as predictor of Organizational Citizenship Behavior

The present study aimed at exploring the linkages between Allen and Meyer’s (1991) three component model of organizational commitment and organizational citizenship behavior as defined by Organ (1988), using a field survey on a randomly selected sample of 77 employees working in National Hydroelectric Power Corporation Ltd., a public sector organization in India. Organizational Commitment was measured using revised version of Organizational Commitment Scale by Allen and Meyer (1997) and organizational citizenship behavior scale (OCBS) developed by Bakhshi and Kumar (2009) was used as an aggregate measure of organizational citizenship behavior (OCB). The results of partial correlation analysis showed that all the three components of organizational commitment-Affective commitment, Continuance commitment and Normative commitment were positively correlated with aggregate measure of OCB. Hierarchical Regression analyses showed no significant impact of demographic variables (age, gender, job tenure, marital status and qualification) on aggregate measure of OCB. Among the three components of organizational commitment, only normative commitment has a significant positive impact on aggregate measure of OCB. Theoretical and practical implications of the results are discussed

ENRICHMENT OF FLUX BY NICKEL TO IMPROVE TENSILE STRENGTH AND HARDNESS IN SUBMERGED ARC WELDING

The world is changing toward a market for productivity benefits highly dependent on technology, which will drive automation in the future. Submerged Arc Welding (SAW) is one of the automatic processes employed in industries. Due to this reason large demand of Submerged Arc Welding equipment and consumables will increase in future. The current work is an effort to study the effect of Nickel metal powder addition in flux, on the tensile strength and micohardness, of IS 2062 steel during submerged arc welding. The effect of Nickel metal powder addition on fluxes by keeping the welding parameters like welding voltage and welding speed constant has been evaluated. Taguchi technique has been used for the design of experiments. The effects of flux, voltage and travel speed have been evaluated on the tensile strength and microhardness. The effec

Evaluaton of hypoglycaemic activity of Aegel marmelos alcoholic seed extract in experimental models of hyperglycemic rats

The present study aimed to investigate the antidiabetic effect of alcoholic seed extract of Aegel marmelos in comparison with glibenclamide in in vivo using alloxan rat model.The diabetic rats were orally given glibenclamide and alcoholic seed extract of Aegle marmelos for 21 days. The effects were studied in vivo. Oral administration of alcoholic seed extract of Aegle marmelos decrease the level of serum glucose, total cholesterol (TCH), triglycerides(TG), low density lipoprotein (LDLP), very low density lipoprotein(VLDLP) significantly while increasing HDL-cholesterol. Alcoholic seed extract of Aegle marmelos was also evaluated for oral glucose tolerance(OGTT) characteristics. In conclusion, alcoholic seed extract of Aegle marmelos had potential antidiabetic activity. Further it has been observed that the seed extract have positive effect on liver and kidney parenchyma

Synergistic Effect of Plant Growth Regulators on Micropropagation of Eclipta alba: A Plant with Diverse Medicinal Properties

Synergism between various plant growth regulators is reported to be a key factor for the development of efficient in vitro propagation for any plant. Therefore, the current study examines the synergistic impact of plant growth regulators on in vitro propagation of Eclipta alba, an important medicinal plant possessing diverse medicinal properties. For the establishment of aseptic cultures, nodal segments were employed as explants on MS medium supplemented with 2.5 μM of 6-benzyle adenine (BA). Varying concentrations of BA and Kinetin (KIN)(0.0-5.0 μM), either alone or in combination with α- naphthalene acetic acid (NAA @ 0.0-5.0 μM) and indole 3-acetic acid (IAA@ 0.0-5.0 μM), were found to be effective for promoting shoot proliferation. Compared to KIN, BA was found to promote shoot proliferation and elongation more effectively. Further, the addition of 0.5μM NAA in the MS medium supplemented with 2.5 μM of BA increased shoot multiplication and elongation frequency from 58 and 17 percent to 65 and 21 percent respectively. The rooting frequency was found to be maximum on 1/2 strength MS medium supplemented with 5.0 μM of indole 3-butyric acid (IBA), which was found to be a superior auxin for inducing roots as compared to the NAA and IAA. With a 75% survival rate, in vitro raised plantlets were effectively acclimatized first in a poly house and later under greenhouse conditions. Molecular analysis was carried out using RAPD markers, with results indicating that the micropropagated plants were genetically identical to the mother plant. The developed micropropagation protocol for E. alba can be used at the commercial level for the mass multiplication of plants

Fluoride Alternatives in the Prevention of Dental Caries: A Review

There is no doubt that fluoride has been playing an important role in the prevention of dental caries and has been incorporated in various products (in both topical and systemic forms). However, few researchers consider fluoride to be a double edged sword as its use as an anticaries agent has been marked by various controversies because of the health concerns associated with the excessive use of the fluorides with its chronic use has been found to be associated with dental fluorosis, skeletal fluorosis, osteoporosis of long bones, carcinomas, renal and gall bladder calcification etc. The efficacy of fluorides to pit and fissured of the tooth surface is also questioned as its effect only seems to be limited to the smooth surface to the tooth. Hence, this review provides the readers with alternative fluoride free delivery mechanisms for caries prevention which can be used as an effective public health measure