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Abstract The variation of properties with temperature have many practical applications in the area of chemical engineering and metallurgy, in the process of extrusion, the materials moving between a feed roll and on carrier belt. Here our intention is to explore the consequences of temperature dependent viscosity and variable thermal conductivity on flow of nanoliquid in a rotating system. Fluid between parallel plates is taken. Energy expression incorporates the exponential heat source. This analysis also explores the attributes of modified Arrhenius energy function with chemical reaction. Boundary layer problems have been computed via NDSolve approach. The obtained solutions are sketched for various estimations of embedded variables of interest. Results pointed out that both axial and transverse velocities show decaying behavior for higher rotation parameter. Thermal field boosts up with an enhancement of thermophoretic and space dependent heat source variables. Moreover the rate of mass transport decays through dimensionless activation energy.

Power system reactive power planning has long been an important issue for the power industry. The widely used VAr compensation device is a SVC with its controller. The problem of planning falls into determination of optimal locations and settings of SVC devices in the power system to be compensated. We propose a new approach of reactive planning using SVCs and nonlinear SVC controllers. This approach considers not only system buses but also the transmission lines to achieve more comprehensive compensation and better system performance especially in view of voltage stability enhancement and control.

Abstract Background Parabolic Trough Solar Collector (PTSC) is one of the most popular and an effective device that converts solar radiation into a heat or useful energy. However, it suffers from high temperature gradient and low thermal efficiency. The solution for this problem is to use new advanced coolants (hybrid nanofluids) in order to enhance PTSC's thermal efficiency. Methods A numerical analysis on the thermo-hydraulic performance of a PTSC receiver's tube equipped with conical turbulators is presented. The Navier-Stokes equations are solved using Finite Volume Method (FVM) coupled with Monte Carlo Ray Tracing (MCRT) method. The flow and thermal characteristics as well as entropy generation of the PTSC's receiver tube are investigated for three hybrid nanofluids (Ag-SWCNT, Ag-MWCNT, and Ag-MgO) having a mixing ratio of (50:50) dispersed in Syltherm oil 800, Reynolds number (5000 to 100,000) and fluid inlet temperatures (400 to 650 K). Significant findings The conical turbulators effectively augmented the thermal performance by 233.4% utilising Ag-SWCNT/Syltherm oil instead of pure Syltherm oil. The performance evaluation criterion is found to be in the range of 0.9–1.82. The thermal and exergetic efficiencies increased by 11.5% and 18.2%, respectively. The maximum decrement in the entropy generation rate and entropy generation ratio are 42.7% and 33.7%.

The radial network is the one which passes through the network without any connection to other supply. It is used for isolated loads like rural areas. Different forward-backward sweep algorithms exist for the load flow analysis of radial distribution systems. A new method of load flow analysis for radial distribution system is explained in this paper. This method is worked out by considering voltage independent loads and voltage dependency loads. The voltage profile results of the proposed method are compared with ratio flow method. Adequate simulations are performed by using Matlab.

Heat energy storage systems were fabricated with the impregnation method using MgO and Mg(OH)2 as supporting materials and polyethylene glycol (PEG-6000) as the functional phase. MgO and Mg(OH)2 were synthesized from the salt Mg(NO3)·6H2O by performing hydrothermal reactions with various precipitating agents. The precipitating agents were NaOH, KOH, NH3, NH3 with pamoic acid (PA), or (NH4)2CO3. The result shows that the selection of the precipitating agent has a significant impact on the crystallite structure, size, and shape of the final products. Of the precipitating agents tested, only NaOH and NH3 with PA produce single-phase Mg(OH)2 as the as-synthesized product. Pore size distribution analyses revealed that the surfaces of the as-synthesized MgO have a slit-like pore structure with a broad-type pore size distribution, whereas the as-synthesized Mg(OH)2 has a mesoporous structure with a narrow pore size distribution. This structure enhances the latent heat of the phase change material (PCM) as well as super cooling mitigation. The PEG/Mg(OH)2 PCM also exhibits reproducible behavior over a large number of thermal cycles. Both MgO and Mg(OH)2 matrices prevent the leakage of liquid PEG during the phase transition in phase change materials (PCMs). However, MgO/PEG has a low impregnation ratio and efficiency, with a low thermal storage capability. This is due to the large pore diameter, which does not allow MgO to retain a larger amount of PEG. The latent heat values of PEG-1000/PEG-6000 blends with MgO and Mg(OH)2 were also determined with a view to extending the application of the PCMs to energy storage over wider temperature ranges.

In order to compete in the global market, engineering organizations are under increasing pressure to design, develop, and deploy products in the market place as quickly as possible with first time quality. In order to achieve these objectives, it is necessary to streamline the design and development process, namely, “transfer of analytical design of Intelligence to Mechatronics intelligence” in an efficient and expedient manner. An increasing pressure exists on the development cycle of control systems to serve this widening application spectrum. The time-to-market of a new product often determines its commercial success. Consequently, design problems have to be discovered as early as possible in the design process in order to take remedial actions. Efficient and accurate tools and procedures are required to support short yet successful development processes. Over the last two decades, commercially available computer has become both increasingly powerful and increasingly affordable. This, in turn, has led to the emergence of highly sophisticated simulation software applications that not only enable high-fidelity simulation of dynamic systems and related controls, but also automatic code generation for implementation in industrial controllers. Simulation tools have been widely used for the design and improvement of electrical systems since the mid twentieth century. The evolution of simulation tools has progressed in step with the evolution of computing technologies. In last ten years, computing technologies have improved dramatically in performance and become widely available at a steadily decreasing cost. Consequently, simulation tools have also seen dramatic performance gains and steady cost decreases. Researchers and engineers now have access to affordable, high-performance simulation tools that were previously too cost prohibitive, except for the largest manufacturers and utilities. The purpose of this paper is to review major milestones that set the stage for the development of the today's real time simulation including sufficient detail to acquaint reader with their basic principles, strength, challenges and its applications.

Risk is the possibility that an undesirable event might occur in the future that will result in some negative consequences. Risk analysis of a system is required to protect the system from risky (more failure prone) components. Reliability Importance measures play an important role in ranking the components according to the impact on the system adequate performance. Risk based measures are useful in identifying the weak components and help in improving the reliability of the overall system efficiently. Risk and Reliability of Substation Automation System (SAS) are most important and desirable design considerations. SAS consists of different components and its applications require real time performance. Three substation automation system architectures are considered in this paper. Two important measures Improvement Potential (IP) and Risk Achievement Worth (RAW) are used to prioritize the components in two types of architectures of SAS. System reliability expressions for all architectures are computed with their reliability block diagrams. On the basis of these two IP and RAW measures the components DCP, ESW and NCCS are most important, BCU and EI are least important components from both maintenance and risk point of view.

Abstract In an effort to minimise electricity consumption and greenhouse gases emissions, the heating, ventilation and air-conditioning sector has focused its attention on developing alternative solutions to electrically-driven vapour-compression cooling. Liquid desiccant air-conditioning systems represent an energy-efficient and more environmentally friendly alternative technology for dehumidification and cooling, particularly in those cases with high latent loads to maintain indoor air quality and comfort conditions. This technology is considered particularly efficient in hot and humid climates. As a matter of fact, the choice of the desiccant solution influences the overall performance of the system. The current paper reviews the working principle of liquid desiccant systems, focusing on the thermodynamic properties of the desiccant solutions and describes an evaluation of the reference thermodynamic properties of different desiccant solutions to identify which thermodynamic, physical, transport property influences the liquid desiccant process and to what extent. The comparison of these thermodynamic properties for the commonly used desiccants is conducted to estimate which fluid could perform most favourably in the system. The economic factors and the effect of different applications and climatic conditions on the system performance are also described. The paper is intended to be the first step in the evaluation of alternative desiccant fluids able to overcome the problems related to the use of the common desiccant solutions, such as crystallization and corrosion to metals. Ionic liquids seem a promising alternative working fluid in liquid desiccant air-conditioning systems and their characteristics and cost are discussed.