Rajiv Chaudhary

Heat utilization from solar and biomass resources are considered for hybridization. Modeling of polygeneration process in hybrid solar-biomass power plant is considered. Thermodynamic evaluation are performed to identify the effect of various parameters. Primary Energy Saving of polygeneration process is determined. a b s t r a c t In the polygeneration process simultaneous production of power, vapor absorption refrigeration (VAR) cooling and multi-effect humidification and dehumidification (MEHD) desalination system from different heat sources in hybrid solar-biomass (HSB) system with higher energy efficiency take place. It is one of the solutions to fulfill energy requirements from renewable sources and also helps in the reduction of carbon dioxide emissions. The VAR cooling system operates using the extracted heat taken from turbine and condenser heat of the VAR cooling system is used in desalination system for production of drinking water as per demand requirement. Though the production of electricity decreases due to extraction of heat from turbine for VAR cooling and desalination, the complete system meets the energy requirements & increases the primary energy savings (PES). The thermodynamic evaluation and optimization of HSB system in polygeneration process for combined power, cooling and desalination is investigated to identify the effects of various operating parameters. Primary energy savings (PES) of polygeneration process in HSB system is achieved to 50.5%. The energy output is increased to 78.12% from this system as compared to simple power plant.

Major structural support to the human body is provided by the skeleton, which comprises several joins through which bones are connected, with each other, forming a structure. Apart from performing various roles of kinematics, posture, muscular contraction control, and internal organs protection, Skeleton also withstands various types of loadings applied to the body in various physical activities. Subsequently, it becomes important to study the mechanical behavior of the bone, through its various mechanical properties like Strength, Toughness, Fatigue strength and Hardness etc, which have been matter of interest in this context. Out of various types of loadings, the suddenly applied load has been more critical to the skeleton as well as bones, as through suddenly applied load or impact considerably more stress is developed in comparison to other loading conditions. Also, the explanation of this mechanical property from the fracture mechanics concept looks to be very prospective, with more and more new possibilities. Although the basic methods of assessing this property is based on load-bearing capacity in form of stress, as done with other engineering materials. But biomaterials like bone, being a living material, happens to be very different which are capable of self-repair and adaptation. Obviously, the Quantitative measurement of toughness of bone would become an integral part of the mechanical assessment of this biomaterial and in evaluating this, we also need to address some other issues like age, activity, deficiencies, disease and therapeutic treatment etc. In this context, the considerations have been made about the issues related to various physical activities, sports, exercises, as well as injuries/fracture and its effect over toughness of bone have been studied. Different studies have been made by the researchers focusing on various aspects of this mechanical property of toughness, with respect to principle, theory, methodology as well as various experimental evaluations done with this biomaterial. In this paper an attempt has been made to make a comparative study of various aspects of evaluating toughness of bone and to assess structural issues etc of the bone in this context.

Ball bearings provide rotational freedom and support for transmitting the load between two ends of machine. Roller bearing defect is a major factor of failure in rotating machinery that affects its proper functioning which results in substantial time and economic losses. Therefore, condition monitoring of roller bearing is important and the study of severity of defects are necessarily required in order to avoid catastrophic consequences. The analysis of signal resulting from measurements taken from outer machineries has proven to be effective, by detection of failure in bearings over rotating shaft. The authors have used a method based on the vibration analysis for detection of defects in rolling element bearings with single or multiple defects on different components of the bearing structure using the time and frequency domain parameters. A dynamic loading model is used in order to create the rotary motion of bearings. A vibration analyser is used for vibration diagnosis and on-sit...

Practice of Energy harvesting is very old, which has been based on established principles and theories, which is utilized in various machines and devices. for powering sensor networks and mobile electronics. Systems can scavenge power from human activity or derive limited energy from ambient heat, light, radio, or vibrations. Ongoing power management developments enable battery-powered electronics to live longer. Such advances include dynamic optimization of voltage and clock rate, hybrid analog-digital designs, and clever wake-up procedures that keep the electronics mostly inactive. Applying suck techniques to larger machines such as treadmill and bicycle, by using various dynamometers in a gym facility or at home can also produce renewable energy in large amount. Humans release a lot of energy from their everyday activities, such as simple breathing and walking. Energy harvesting's true legacy dates to the water wheel and windmill, and credible approaches that scavenge energy ...

Surface Roughness is an important aspect in mechanical engineering design depending on the application of the
component in usage. Friction, wear and power transmission depend on material surface and contact environment. Objective
Consideration may be with respect to aesthetic view, stress condition, precision fits, smooth motion etc. However, the critical
constraints are surface roughness, tolerances and nominal size for the selection criteria of the parts. Since Taguchi method
systematically reveals the complex cause and evolves the relationship between design parameters along with taking
consideration of performance. Many researchers have used Taguchi techniques for design of experimental studies. The
present study focusses on the investigations made on drilling using Taguchi Techniques.

For developing more fuel-efficient and environmental friendly internal combustion (IC) engines, researchers are doing tremendous efforts in the area in addition to main thrust on the exploration of sustainable renewable fuels. In light of this, studies for reductions of mechanical losses at various interfaces in IC engines are vital task irrespective of fuels being used in the engines. Therefore, in this paper authors have explored comparative performance of a diesel engine fuelled with diesel and biodiesel by reducing the friction at the piston rings and cylinder liner interfaces. Friction at the interface is reduced through modification in face profiles of piston rings. This paper is based on studies having twin objectives, which are: 1. Comparison of performance parameters of a commercial diesel engine fuelled with diesel and Jatropha based biodiesel (B100); and 2. Accessing the performance parameters of the engine with both the fuels using conventional and three different designs of the face profiles of the piston rings. The performance parameters of the engine have been improved significantly with one of face profiles of the piston rings under study irrespective of fuels used. Based on the results of the experiments, it is realized by the authors of this paper that there is a strong need to study exhaustively the combined roles of optimized face profiles of the piston rings and biodiesel fuels for further improving the performance of IC engines

Abstract: Fast depletion of world’s petroleum reserves and increasing  ecological  concerns  has  created  a
great demand for environmentally benign renewable energy resources.  Biodiesel  has  emerged  as  a
sustainable alternative to petroleum origin diesel and its usage have been encouraged by many countries.
Transesterification reaction is the most common process to produce biodiesel from variety of vegetable oils and
animal fat. Transesterification process depends upon a number of process parameters which are required to be
optimized in order to maximize the biodiesel yield. Thumba oil is an underutilized non-edible vegetable oil,
available in large quantities in Rajasthan, India and its potential suitability as a biodiesel feedstock is still not
evaluated comprehensively. In this research paper, the transesterification process for production of Thumba
oil methyl ester has been analyzed and the various process variables like temperature, catalyst concentration,
amount of methanol and reaction time have been optimized with the objective to maximize yield. The optimum
conditions for transesterification of Thumba oil with methanol and KOH as catalyst were found to be 60°C
reaction temperature, 6:1 molar ratio of Thumba oil to methanol, 0.75% catalyst (w/w ) and 1 hour reaction time. oil
Key words: Thumba oil % Transesterification % Process optimization % Maximum yield

Piston in the internal combustion (IC) engine is robust, dynamically loaded tribo-pair that reciprocates continuously at varying temperature. Study has been made by various researchers on piston design, dynamics, fatigue and wear at the interface with other element in contact along with their effects on IC engines. It was found that the friction coefficient increases with increasing surface roughness of liner surface and thermal performance of the piston increases with increased coating thickness. The free material liberated due to deep scoring between the piston and liner snowballs, leads to seizure failure.
Keywords: Piston, Tribo-pair, IC Engines, Fatigue, Wear.