RK University

About: RK University is a education organization based out in Rajkot, Gujarat, India. It is known for research contribution in the topics: Electrical discharge machining & Metaheuristic. The organization has 343 authors who have published 423 publications receiving 2911 citations.

High Prevalence of Cardiac Parvovirus B19 Infection in Patients With Isolated Left Ventricular Diastolic Dysfunction

Abstract: Background— The etiology of left ventricular (LV) isolated diastolic dysfunction often remains unclear. In the present study, we report a strong association between parvovirus B19 (PVB19) genomes and isolated LV diastolic dysfunction. Methods and Results— In 70 patients (mean±SD age, 43±11 years) admitted with exertional dyspnea and/or reduced exercise tolerance despite preserved LV systolic contractility (ejection fraction=68%), isolated diastolic dysfunction was clinically suspected. Patients with classic risk factors for diastolic dysfunction such as hypertension, coronary heart disease, diabetes mellitus, or pulmonary disease had been excluded. Diastolic function was assessed by echocardiography and LV and RV catheterization. Endomyocardial biopsies (EMBs) were analyzed for the presence of storage or infiltrative diseases or myocarditis, including molecular screening for cardiotropic virus genomes. In a substudy of 24 patients who reported atypical angina, coronary endothelial function was additionall...

Biodiesel production from Karanja oil and its use in diesel engine: A review

Abstract: Biodiesel is produced from renewable resources like vegetable oils and animal fats. It can use as a fuel in diesel engine by blending with diesel or in pure form. Biodiesel blended diesel fuel emits less harmful gasses compare to diesel fuel. India is developing country where more than 70% of petroleum products are import. Biodiesel production from local resources provides energy security; reduce import bill, generate employment and reduced emissions of harmful gasses. Production of biodiesel from edible oil is not economical for India due to its higher price. Various non-edible oil seeds like Jatropha, Karanja, Mahua, Sal, Neem etc. are widely available in India. It is less costly compared to edible oils. Among them, Karanja has a potential to be used as a basic feedstock for the production of biodiesel. Karanja trees can grow on sides of roads, canal and boundary portion of agricultural lands with minimum care. Its seeds contain 27–39% of the oil. Transesterification, Pyrolysis, Microemulsion and Blending are four primary methods for the production of biodiesel. The yield of 97% of Karanja oil methyl ester (KOME) was obtained from Karanja oil (KO) by transesterification process at 65 °C using 1 wt% of KOH, 6:1 M ratio of methanol to oil in 2 h. The 20% blend of KOME with diesel (B20) is the most optimized blend for a diesel engine. The Brake thermal efficiency (BTE) and Brake specific fuel consumption (BSFC) of B20 is comparable to diesel. Emissions of CO, HC and smoke are reduced and NOx is increased with increasing blending of KOME with diesel. This paper focuses on the production methods of KOME, parameters that affect the yield, engine performance by pure KOME and its various blends with diesel, economic aspects, environmental considerations and sustainability of Karanja oil as an Indian perspective.

Truss optimization with natural frequency bounds using improved symbiotic organisms search

Abstract: Many engineering structures are subjected to dynamic excitation, which may lead to undesirable vibrations. The multiple natural frequency bounds in truss optimization problems can improve dynamic behaviour of structures. However, shape and size variables with frequency bounds are challenging due to its characteristic, which is non-linear, non-convex, and implicit with respect to the design variables. As the main contribution, this work proposes an improved version of a recently proposed Symbiotic Organisms Search (SOS) called an Improved SOS (ISOS) to tackle the above-mentioned challenges. The main motivation is to improve the exploitative behaviour of SOS since this algorithm significantly promotes exploration which is a good mechanism to avoid local solution, yet it negatively impacts the accuracy of solutions (exploitation) as a consequence. The feasibility and effectiveness of ISOS is studied with six benchmark planar/space trusses and thirty functions extracted from the CEC2014 test suite, and the results are compared with other meta-heuristics. The experimental results show that ISOS is more reliable and efficient as compared to the basis SOS algorithm and other state-of-the-art algorithms.

Assessment of operational feasibility of waste vegetable oil based bio-dielectric fluid for sustainable electric discharge machining (EDM)

Abstract: Since the first application of electric sparks for the material removal was demonstrated, the electric discharge machining (EDM) process has gone through considerable changes in terms of technology and application. The process has surpassed the technological barriers by overcoming its then thought limitations like processing speed, material conductivity, dimensional and geometrical accuracies, and surface finish. However, environmental impact due to release of toxic emission products, operator health concerns due to release of toxic fumes, vapours and aerosols during the process, poor operational safety due to fire hazards and electromagnetic radiation, and toxic and non-biodegradable dielectric waste generated are some of the concerns still prevailing in EDM process. Authors, in this paper, have assessed the operational feasibility of waste vegetable oil (WVO) as possible alternative dielectric fluid and compared the response patterns of WVO with hydrocarbon oil, kerosene. Experiments were performed using spark current, gap voltage, pulse on time (pulse duration) and pulse off time (pulse interval) as control parameters to study the response behaviour for material removal rate (MRR), electrode wear rate (EWR) and tool wear ratio (TWR). The results obtained reveal that WVO-based bio-dielectric fluid can be used as an alternate to hydrocarbon-, water- and synthetic-based dielectric fluids for EDM. Besides the successful trials for operational feasibility assessment, application of bio-fluids offers a cleaner, greener and safer solution for dielectric to improve sustainability of EDM process by improving environmental friendliness, operational safety and personnel health issues of the process. Based on the experimental results and observations, the authors have suggested further scope of works to improve sustainability of the EDM process.

Investigations on technical feasibility of Jatropha curcas oil based bio dielectric fluid for sustainable electric discharge machining (EDM)

Abstract: The emergence of the concept of sustainable manufacturing practices and, therefore, the requirement to adapt ISO-14000 standards, it is essential to evaluate all manufacturing practices using sustainability criteria. Use of vegetable oil-based fluids for industrial applications has a higher sustainability index compared to hydrocarbon and synthetic based fluids. In this paper, the authors have investigated the technical feasibility of newly proposed Jatropha curcas oil based bio dielectric (Jatropha BD) fluid for electric discharge machining (EDM) with a view to improving the sustainability of EDM process. Experimental analysis has been performed for material removal rate (MRR), surface roughness (SR) and surface hardness (SH) under the influence of current, gap voltage, pulse on time and pulse off time. analysis of variance (ANOVA) has been performed to identify the significance of the control parameters on the response characteristics. The results obtained indicate that Jatropha BD resulted in higher MRR, lower SR and improved SH than kerosene. Moreover, the response patterns of Jatropha BD are similar to kerosene which is an indication that material melting and evaporation mechanics are as like kerosene. Regression models have been generated to model the response behavior of the parameters. Regression models predicted the response of the parameters in good conformance. It is suggested that Jatropha oil based bio dielectric fluids can be used as an alternative to hydrocarbon based dielectric for improving sustainability of EDM process.