L. Velazquez-Avelar

Bio: L. Velazquez-Avelar is an academic researcher from Universidad Autónoma del Estado de Morelos. The author has contributed to research in topics: Coefficient of performance & Plate heat exchanger. The author has an hindex of 4, co-authored 4 publications receiving 768 citations.

Temperature and concentration fields in a generator integrated to single stage heat transformer using Water/Carrol mixture

Abstract: The generator is the starter device of single stage heat transformer (SSHT) and its characteristics have main effects on the overall efficiency of this kind of absorption machines. This article reports a study of the generation of steam and changes in the concentration of the working solution (Water/Carrol mixture) into a plate heat exchanger as a function of its horizontal and vertical position by gravity effect. It is considered the analysis of six experimental tests; two were evaluated in a plate heat exchanger in a horizontal position and four in a vertical position (90 degree inclination). The generation of steam and increased concentration of the working solution are more sensitive to the vertical position of exchanger than in horizontal position. The results of numerical-experimental analysis indicates that a heat exchanger in horizontal position, the steam generation and the change in the concentration of the working solution occurring in the middle of the plate (or at greater distance depending to the thermodynamic conditions) and instantly in vertical position (at the input of the plate).

Dynamic nanofin heat sinks

Abstract: The limitation of hot spot cooling in microchips represents an important hurdle for the electronics industry to overcome with coolers yet to exceed the efficiencies required. Nanotechnology-enabled heat sinks that can be magnetophoretically formed onto the hot spots within a microfluidic environment are presented. CrO2 nanoparticles, which are dynamically chained and docked onto the hot spots, establish tuneable high-aspect-ratio nanofins for the heat exchange between these hot spots and the liquid coolant. These nanofins can also be grown and released on demand, absorbing and releasing the heat from the hot spots into the microfluidic system. It is shown that both high aspect ratio and flexibility of the fins have a dramatic effect on increasing the heat sinking efficiency. The system has the potential to offer a practical cooling solution for future electronics.

A Comprehensive Survey on Particle Swarm Optimization Algorithm and Its Applications

Abstract: Particle swarm optimization (PSO) is a heuristic global optimization method, proposed originally by Kennedy and Eberhart in 1995. It is now one of the most commonly used optimization techniques. This survey presented a comprehensive investigation of PSO. On one hand, we provided advances with PSO, including its modifications (including quantum-behaved PSO, bare-bones PSO, chaotic PSO, and fuzzy PSO), population topology (as fully connected, von Neumann, ring, star, random, etc.), hybridization (with genetic algorithm, simulated annealing, Tabu search, artificial immune system, ant colony algorithm, artificial bee colony, differential evolution, harmonic search, and biogeography-based optimization), extensions (to multiobjective, constrained, discrete, and binary optimization), theoretical analysis (parameter selection and tuning, and convergence analysis), and parallel implementation (in multicore, multiprocessor, GPU, and cloud computing forms). On the other hand, we offered a survey on applications of PSO to the following eight fields: electrical and electronic engineering, automation control systems, communication theory, operations research, mechanical engineering, fuel and energy, medicine, chemistry, and biology. It is hoped that this survey would be beneficial for the researchers studying PSO algorithms.