Development and performance analysis of a novel agitated vessel

The objective of the present study was to design, fabricate and evaluate the performance of a novel airi-nducing impeller system with a specially designed air-inducing tube-set. The novel air-inducing impeller system, when attached to a conventional baffled agitated vessel, could convert it into an air-inducing reactor. Water was used as the working fluid and the characteristics of the impeller system such as critical speed, power consumption and gas holdup were investigated by varying the gas free liquid level, orifice immersion depth, bottom clearance and impeller speed. Results showed that this novel air-inducing impeller system induced the air at speeds lower than the critical speeds reported by most of the investigators in the literature.     

Prediction and analysis of surface roughness characteristics of a non-ferrous material using ANN in CNC turning

Surface roughness, an indicator of surface quality is one of the most-specified customer requirements in a machining process. For efficient use of machine tools, optimum cutting parameters (speed, feed, and depth of cut) are required. So it is necessary to find a suitable optimization method which can find optimum values of cutting parameters for minimizing surface roughness. The turning process parameter optimization is highly constrained and non-linear. In this work, machining process has been carried out on brass C26000 material in dry cutting condition in a CNC turning machine and surface roughness has been measured using surface roughness tester. To predict the surface roughness, an artificial neural network (ANN) model has been designed through feed-forward back-propagation network using Matlab (2009a) software for the data obtained. Comparison of the experimental data and ANN results show that there is no significant difference and ANN has been used confidently. The results obtained conclude that ANN is reliable and accurate for predicting the values. The actual R _a value has been obtained as 1.1999???m and the corresponding predicted surface roughness value is 1.1859???m, which implies greater accuracy.     

Natural Convection in a Differentially Heated Cavity with Parallel Heat-Generating Baffles

Natural convection in a horizontal differentially heated square cavity containing two vertical heat generating baffles is studied numerically. The baffles are assumed to generate heat uniformly at the same or different rates. Asymptotic steady-state results for the vorticity–stream function formulation are presented in the form of streamline and isotherm plots. The fluid flow, heat transfer, and average Nusselt number are investigated for different heat generation ratios and spacing between the baffles. Convection within the cavity gets augmented for increasing values of heat generation ratio. When the two baffles are located very near the cavity walls, an increase in heat generation ratio induces a strong buoyancy convective flow. When they are very close to each other an increase in heat generation ratio strengthens the innermost cell around the baffles, which in turn drives the global flow at a faster rate through a pair of intermediate inner cells. It is found that the blocking effect of the baffles strongly depends on heat generation ratio and spacing between the baffles. The heat transfer rate varies nonlinearly against spacing between the baffles, and the possible physical reason is given.     

Wind energy potential at Palkalainagar

This paper uses the Weibull's distribution function to describe the wind speed frequency distribution at Palkalainagar (geographical co-ordinates N : 9°54′, E : 78°54′), Madurai, India using the one year data available. Weibull's parameters are used to estimate the wind data parameters for the site. Of the wind data parameters the most important one is the annual specific output (T_A). This is used in determining the annual energy output of a Wind Energy Conversion System (WECS) and in conducting cost-benefit analysis of wind-electricity generation. The parameter is used in evaluating the efficiency of WECS in the same site. Results show the possibilities of harnessing wind energy towards electricity generation.     

Minocycline Loaded Hybrid Composites Nanoparticles for Mesenchymal Stem Cells Differentiation into Osteogenesis

Bone transplants are used to treat fractures and increase new tissue development in bone tissue engineering. Grafting of massive implantations showing slow curing rate and results in cell death for poor vascularization. The potentials of biocomposite scaffolds to mimic extracellular matrix (ECM) and including new biomaterials could produce a better substitute for new bone tissue formation. A purpose of this study is to analyze polycaprolactone/silk fibroin/hyaluronic acid/minocycline hydrochloride (PCL/SF/HA/MH) nanoparticles initiate human mesenchymal stem cells (MSCs) proliferation and differentiation into osteogenesis. Electrospraying technique was used to develop PCL, PCL/SF, PCL/SF/HA and PCL/SF/HA/MH hybrid biocomposite nanoparticles and characterization was analyzed by field emission scanning electron microscope (FESEM), contact angle and Fourier transform infrared spectroscopy (FT-IR). The obtained results proved that the particle diameter and water contact angle obtained around 0.54 ± 0.12 to 3.2 ± 0.18 µm and 43.93 ± 10.8° to 133.1 ± 12.4° respectively. The cell proliferation and cell-nanoparticle interactions analyzed using (3-(4,5-dimethyl thiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt) MTS assay (Promega, Madison, WI, USA), FESEM for cell morphology and 5-Chloromethylfluorescein diacetate (CMFDA) dye for imaging live cells. Osteogenic differentiation was proved by expression of osteocalcin, alkaline phosphatase activity (ALP) and mineralization was confirmed by using alizarin red (ARS). The quantity of cells was considerably increased in PCL/SF/HA/MH nanoparticles when compare to all other biocomposite nanoparticles and the cell interaction was observed more on PCL/SF/HA/MH nanoparticles. The electrosprayed PCL/SF/HA/MH biocomposite nanoparticle significantly initiated increased cell proliferation, osteogenic differentiation and mineralization, which provide huge potential for bone tissue engineering.