bala murugan

Heat exchangers are one of the most important devices of mechanical systems in modern
society. Most industrial processes involve the transfer of heat and more often they require
the heat transfer process to be controlled. A heat exchanger is the heat exchanged between two media, one being cold and the other being hot. There are different types of heat exchanger, but the type which is widely used in industrial application is the shell and tube. In this study, experiments conducted based on fully replicable five-factor, five-level central composite design. Regression modelsare developed to analyse the effects of shell and tube heat exchange process parameter such as inlet temperature of hot fluid and flow rates of cold and hot fluid. The output parameters of a heat exchanger are used for analysing the direct and interactive effects of heat exchange process parameters.

A study on the effect of fiber length and fiber surface modification on tensile property of alkaline treated coir fiber reinforced epoxy composites is presented in this paper. The fiber surface treatment was carried out using Sodium Lauryl Sulfate (SLS) solution at five different concentrations, 2%, 4%, 6%, 8% and 10% respectively. Each group of the coir fiber was treated for 10 days. For each group the coir fibers experiments were conducted for different fiber lengths namely 10, 20, and 30mm. The SLS treated coir fiber was used as a reinforcement and epoxy was used as a matrix to fabricate the composites. The tensile strength of different samples of composites was measured. Increased SLS concentration in fiber treatment was found to increase the tensile strength up to 4% and further increase in SLS concentration reduced the tensile strength, also, experimental results showed that an increase in fiber length increased tensile strength. The maximum tensile strength of the composite was found to be uniformly occurring for 4% SLS with 30mm fiber length composite samples. Based on the nonlinear regression analysis the tensile strength equation was proposed for coir fiber reinforced epoxy composites.

An analytical study was performed to study effects of thermo-diffusion and chemical reactions on a three-dimensional MHD mixed convective flow of dissipative fluid along an infinite vertical porous plate with transverse sinusoidal suction velocity. The parabolic partial differential equationsgoverning the fluid flow, heat transfer, and mass transfer were solved using perturbation technique and the expressions for velocity, temperature, and concentration distributions were obtained. Expressions for skin friction at the plate in the direction of the main flow, rate of heat transfer, and mass transferfrom the plate to the fluid were derived in a non-dimensional form. Velocity,temperature, concentration, amplitudes of the perturbed parts of skin friction, rate of heat transfer, rate of mass transfer, and skin friction at the plate are presented in graphs and effects of various physical parameters like Hartmann number M, Prandtl number Pr, Reynolds number Re, Schmidt number Sc, Soret number So, Grashof number for heat transfer Gr, Grashof number for mass transfer Gm, and chemical reaction parameter Kr on the above flow quantities were analyzed and then the obtained results were physically interpreted.

The aim of the present study was to compare the immediate (Im) and the delayed (De) protocols for placement of single-tooth implants. After allocation to the Immediate and Delayed groups by random, 14 patients were treated with a single-tooth implant with self-threaded internal hex and selective integrated surface (Hi- tec, life care implants) in the anterior or molar region of the maxilla or the mandible on immediate (Im) or 6 months (De) following tooth extraction, respectively. Fourteen patients attended a follow-up visit 18 months after implant placement corresponding to 1 year of loading of the implant restorations. Peri-implant and prosthetic parameters were evaluated clinically and marginal bone levels measured on radiographs. None of the Implant restorations had failed after 1 year of function. Probing pocket depths were reduced by up to 1.5mm on average from the time of loading to the 18 month follow-up and at that time, no significant difference between the Im and De groups was found (4.3 versus 4.2 mm). A statistically significant radiographic marginal bone loss had occurred in the Im group (13.46%) as well as in the De group (15.62%) in the follow-up period. However, a mean marginal bone level of approx. 1.5mm in both groups measured from the implant–abutment junction was found to be acceptable. It was demonstrated that probing pocket depths, papilla fill, width of keratinized mucosa, thickness of peri-implant mucosa and marginal bone levels after 1year of loading of the implant-retained crowns were not influenced by either immediate or delayed implant placement protocols. Furthermore, no severe prosthodontics complications, such as screw loosening or porcelain fractures, arose in this study material. High success rates of single-tooth implants after 1 year of function were achieved using the immediate and delayed single tooth implant placement protocols.

Field experiments were conducted during 2002-2003 on clay loam, sandy loam and red loam soil at Sivapuri, Chidambaram, Tamil Nadu, to evaluate the efficacy of vermicompost on the physico-chemical and biological characteristics of the soils and on the yield and nutrient content of blackgram - Vigna mungo, in comparison to inorganic fertilizers nitrogen, phosphorous, potassium. Vermicompost had increased the pore space, reduced particle and bulk density, increased water holding capacity, cation exchange capacity, reduced pH and electrical conductivity, increased organic carbon content, available nitrogen, phosphorous, potassium and microbial population and activity in all the soil types, particularly clay loam. The yield and quality (protein and sugar content in seed) of blackgram was enhanced in soils, particularly clay loam soil. On the contrary, the application of inorganic fertilizers has resulted in reduced porosity, compaction of soil, reduced carbon and reduced microbial activity.