Experimental Studies on the Grind-Hardening Effect in Cylindrical Grinding

In recent years high-strength and high-temperature alloys are used for structural and other applications. These newer high-performance materials are inherently “more difficult to machine” and also necessitate the need for higher dimensional and geometrical accuracy. Grinding is one of the most familiar and common abrasive machining processes used for the finishing operation. Compared to other machining processes such as turning, milling, etc., the specific energy developed during grinding is very high. At a critical level of specific grinding energy, the temperature rise[1]experienced by the workpiece may be such that thermal damage is induced. Heat damage induced by the grinding process is well documented and may be categorized by temper colors that are at least unsightly and probably indicative of more serious damage, including thermal cracks, tempered zone, etc.,[2]which can lead to catastrophic failure of critical machine parts that shortens the life of products subject to cyclic loading. In this work, a new heat treatment process called “grind hardening” and a mathematical model are introduced, and this work deals with how the in-process energy in grinding can be effectively utilized to improve the surface hardness and surface texture, and also to prevent damages. An experimental study has also been carried out in grinding AISI 6150 and AISI 52100 steels with an alumina wheel, and the results are discussed.     

SHRINKAGE OF STRAWBERRIES DURING MICROWAVE DRYING

ABSTRACT

Strawberries were pretreated with ethyl oleate and sodium hydroxide solution to make the skin transparent to moisture diffusion. The treated berries were dried with convective air at 45°C and microwaves at two power levels of 0.1 and 0.2 W/g. During the drying process change in shrinkage ratio with respect to moisture ratio was studied. Also, the change in equivalent diameter of strawberries in correlation with moisture ratio was investigated. During drying the variation in surface and centre temperatures with moisture content and time was studied. It was observed that there is a direct relation between the shrinkage and moisture ratio. The equivalent diameter of the berry has a logarithmic function with respect to the moisture ratio.     

Optimisation of hydrothermal treatment for dehulling pigeon pea

This study was carried out to investigate the effect of hydrothermal treatment and drying time at a constant drying temperature of 50 °C on the dehulling behavior of pigeon pea seed. Response surface methodology (RSM) based on a two-factor, five-level, central composite design was employed to study the effect of the independent variables and optimize processing conditions. A second-order polynomial model described dehulling quality in terms of: (1) dehulled seeds, (2) undehulled seeds, (3) broken seeds, (4) powder loss and (5) dehulling efficiency. The process parameters showed significant effects on dehulled seeds and dehulling efficiency. The optimized processing conditions for maximum dehulled seeds, dehulling efficiency and minimum powder loss were a hydrothermal treatment time of 10.2 min and a drying time of 2.9 h.     

Fuzzy stability of a rational functional equation and its relevance to system design

This study demonstrates the solution and various stabilities of a rational functional equation involving two variables by means of fixed point tactic in the vicinity of Felbin's type fuzzy normed spaces. Only few functional equations are dealt to design systems or to model problems in real time examples. The functional equation considered in this paper focuses on designing various systems involving ridigity modulus and pressure.     

Analysis of temperature effect on ceramic brick production from alluvial deposits, Tamilnadu, India

This study focuses on the thermal behaviour of alluvial clays in the production of ceramic brick industries, which are largely found on the bank of the Cauvery river, Tamilnadu, India. Clay bars were prepared which consisted of quartz, kaolinite, illite, chlorite, feldspars and iron oxides. The test samples were fired in the range of 700–1100 °C and were examined with chemical analysis, thermogravimetric–differential thermal analysis (TG–DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). An increase in firing temperature resulted in dehydroxylation of clay minerals, persistence of quartz and formation of Ca-anaesthetic plagioclase. SEM images visualized the vitrification of the fired bricks, which increased the compressive strength of the fired bars. The bricks made with alluvial clays displayed less water absorption and higher compressive strength, indicating that they could be used in the brick industry. The results of this work assisted the industries to select more appropriate natural clay composition and firing dynamics for making the bricks.