Bijoy Mandal

Chemical and nutritional evaluation ofPongamia glabra oil andAcacia auriculaeformis oil

Karanja seed(Pongamia glabra) oil contains toxic flavonoids including 1.25% karanjin and 0.85% pongamol. After refining the oil resembles peanut oil in composition and is free from toxic flavonoids, bitterness and unpleasant odors. Akashmoni seed(Acacia auriculaeformis) oil is rich in stearic acid (31%), and nearly two-thirds of its glyceride is GS2 U (disaturated monounsaturated), mostly SOS (saturated-stearic acid and unsaturated-oleic acid). Nutritional evaluations of these two refined seed oils were carried out in rats by feeding the respective oils and peanut oil as control at 10% level in a 20% protein diet for 12 weeks. The animals fed karanja oil showed poor growth performance, altered lipid metabolism and fatty infiltration in liver. Akashmoni oil in the diet of rats did not reveal growth retardation or any abnormalities in evaluations of lipid parameters of serum and liver or histopathological findings. The results of this study indicate that refined karanja oil is toxic to rats and may not be desirable for edible purposes, while akashmoni oil may be desirable.

Development of a Grinding Fluid Delivery Technique and Its Performance Evaluation

In grinding process, a stiff air layer is generated around the wheel due to rotation of porous grinding wheel at high speed. This stiff air layer restricts fluid to reach deep inside the grinding zone. Conventional method of fluid delivery system is not capable of penetrating this stiff air layer, and thus cannot control grinding temperature and thermal defects effectively. In this work, formation of stiff air layer has been studied experimentally by measuring the variation of air pressure around grinding wheel periphery at different conditions. A pneumatic barrier setup has been developed first time for restricting the stiff air layer around grinding wheel. It is found from analysis of variance (ANOVA) that both pneumatic barrier position and orientation have significant effects on suppressing air layer pressure around the grinding wheel. Using the pneumatic barrier, reduction of air pressure up to 53% has been observed experimentally. Hence, it reduces wastage of grinding fluid, leading to less environmental problem. Surface grinding experiments using the pneumatic barrier setup shows remarkable reduction in forces and surface roughness over flood cooling conditions expectedly due to better penetration of fluid in the grinding zone, showing its applicability.

Protease inhibitors and in vitro protein digestibility of defatted seed cakes of akashmoni and karanja.

Trypsin and chymotrypsin inhibitor activities of defatted seed meals of akashmoni (Acacia auriculaeformis) and karanja (Pongamia glabra) were studied before and after detoxification. Protease inhibitor activities were significantly higher in the unprocessed seed meals when compared with the processed seed meals. Detoxification also improved the in vitro protein digestibilities of these seed meals significantly. Processed meals of these legume seeds, with lower protease inhibitor activities and higher protein digestibilities, could readily be used as animal feed.

Predictive Modeling and Investigation on the Formation of Stiff Air-Layer around the Grinding Wheel

In grinding process, a stiff air layer is generated around the wheel periphery due to high surface speed of the porous grinding wheel. This stiff air layer restricts grinding fluid to reach deep inside the grinding zone. The formation of stiff air layer has been studied experimentally by obtaining the variation of air pressure around the wheel periphery under different wheel speeds. With the help of the experimental data, a mathematical model has been developed to predict the pressure of the stiff layer of air under different wheel speed. From the model it is found that at close proximity to the wheel, air pressure obtained is very high, and this establishes quantitatively the formation of stiff air layer around the grinding wheel.

Improving Grindability of Inconel 600 Using Alumina Wheel through Pneumatic Barrier Assisted Fluid Application

A Stiff Air Layer, Formed around a Rotating Grinding Wheel, Tends to Restrict Grinding Fluid Penetrate Deep inside the Grinding Zone. for this, much Fluid Is Wasted, and Thermal Defects in Grinding May Not Be Controlled. in the Present Experimental Work, a Flood Cooling System with Pneumatic Barrier Is Used for Delivering Grinding Fluid. the Pneumatic Barrier Breaks the Stiff Air Layer, and Therefore, Grinding Fluid Reaches Grinding Zone. an Exotic Nickel Base Alloy, Inconel 600, Is Taken for Surface Grinding Experiments Using an Infeed of 30 µm under Different Environmental Conditions. the Effect of Different Experimental Conditions Is Investigated in Respect of Grinding Force, Chip Formation, Surface Quality and Wheel Condition. the Experimental Result Shows that Grinding Forces and Wheel Wear Are Remarkably Reduced, and Favourable Chips and Good Surface Quality Are Obtained with the Use of Flood Cooling along with Pneumatic Barrier Setup Compared to other Environmental Conditions.

Effect of fluid concentration using a multi-nozzle on grinding performance

Grinding fluid, apart from controlling temperature produced at the wheel-work contact zone by way of cooling also helps in lubrication which is achieved by reduction of friction at the wheel-workpiece interface. In the present experimental investigation, grinding fluid is delivered into the grinding zone by a multi-nozzle system in order to determine grindability of low alloy steel at different fluid concentrations. A comparative study has been made among dry and wet grinding using three different coolant concentrations, considering various response parameters, to assess grinding performance at a particular in feed. It is found that high concentration of oil in the fluid produced good results in terms of force requirement and surface roughness.

Study of the Behavior of Air Flow around a Grinding Wheel under the Application of Pneumatic Barrier

In grinding process, a stiff air layer is generated around the wheel due to rotation of the porous grinding wheel at a high speed. This stiff air layer restricts fluid to reach deep inside the grinding zone. Conventional method of fluid delivery system is not capable of penetrating this stiff air layer, and generally, results in wastage of large amount of grinding fluid that leads to environmental pollution. Several attempts have been made to adopt certain means to improve better penetration of grinding fluid inside the grinding zone. In this work, formation of stiff air layer has been studied experimentally by measuring the variation of air pressure around grinding wheel periphery at different conditions. A pneumatic barrier set-up has been developed first time for restricting the stiff air layer around grinding wheel. The reduction of air pressure around grinding wheel has been observed at various pneumatic pressures. Using the pneumatic barrier, maximum reduction of air pressure up to 53% has been observed experimentally. This pneumatic barrier system reduces deflection of grinding fluid away from wheel, and hence, the reduction in wastage of grinding fluid, leading to less problem related to environment.