A review of stimuli-responsive shape memory polymer composites

Gravitational Search Algorithm (GSA) is an optimization method inspired by the theory of Newtonian gravity in physics. Till now, many variants of GSA have been introduced, most of them are motivated by gravity-related theories such as relativity and astronomy. On the one hand, to solve different kinds of optimization problems, modified versions of GSA have been presented such as continuous (real), binary, discrete, multimodal, constraint, single-objective, and multi-objective GSA. On the other hand, to tackle the difficulties in real-world problems, the efficiency of GSA has been improved using specialized operators, hybridization, local search, and designing the self-adaptive algorithms. Researchers have utilized GSA to solve various engineering optimization problems in diverse fields of applications ranging from electrical engineering to bioinformatics. Here, we discussed a comprehensive investigation of GSA and a brief review of GSA developments in solving different engineering problems to build up a global picture and to open the mind to explore possible applications. We also made a number of suggestions that can be undertaken to help move the area forward.

A comprehensive survey on gravitational search algorithm

The food traceability regulations of 21 Organization for Economic Co-Operation and Development (OECD) countries were examined with attention to whether these regulations are comprehensive for all food commodities and processed foods. The countries were evaluated based on responses to a series of questions that were developed to allow assessment of their traceability programs. The questions sought background information on whether: mandatory traceability regulation(s) exists at the national level within a given country; regulations include imported products, and the nature of required documentation for imports; an electronic database(s) for traceability exists and, if present, its accessibility; and labeling regulations allow consumer access and understanding of traceability. The examination ranked the countries that have specific traceability regulations for all commodities, both domestic and imports, as "Progressive," while countries with less broad or stringent regulations were ranked as "Moderate," and countries that were still in the developmental stage of mandatory or industry-led traceability requirements were ranked as "Regressive." Aggregate scores were developed from all of the rankings, determined on the basis of the questions, for each of the 21 countries, to provide an overall world ranking score. The aggregate scores were "Superior," "Average," or "Poor."

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Comparison of Global Food Traceability Regulations and Requirements

A review on the fatigue behavior of Ti-6Al-4V fabricated by electron beam melting additive manufacturing

The assessment of pollution levels of heavy metals soil contamination is significant to human health and environmental management. The purpose of this article is to apply two methods, which are Principal component analysis (PCA) and Geoaccumulation index ( I geo ), to assess heavy metals contamination levels in the area around copper mine tailing, and to compare the results with Hakanson potential ecological risk index techniques (RI). The rank of soil Cd pollution levels, which is assessed using I geo , is consistent with the one by RI, while the PCA assessments result of comprehensive contamination level in soil discrepancy with RI and I geo . PCA concerned with the distribution of all elements in soil, while I geo and RI are mainly determined by the elements with high concentration or big Toxic Response Factor value. The combined application of PCA and I geo can effectively identify the comprehensive and single pollution levels of elements in soil, thus important to the extent determination of heavy metals pollution in soil.

Assessment of Soil Heavy Metal Pollution with Principal Component Analysis and Geoaccumulation Index

Electrical discharge machining (EDM) is a non-traditional manufacturing process of removing material. EDM system consists of a shaped tool and the work piece, which are connected to a power supply and placed in a dielectric fluid. EDM pulse power generator applies voltage pulses between the electrode and workpiece to generate sparks through the gap. The essential requirement for EDM system is to obtain the output waveform similar to the ideal EDM waveform. The design is based on transistor type pulse power generator circuit. This paper discuss in modeling of current and voltage gap waveform for EDM system.

Model of pulse power generator in electrical discharge machining (EDM) system

This paper proposes an isolated flyback switch mode power supply (SMPS) light-emitting diode (LED) driver for lighting application. The LED driver features a single-stage AC/DC converter with minimal number of components which help to cut its cost. The LED driver is using a single switching transistor, without supplementary inductors, correctional circuitry, or clamping action, thus ensuring a low cost design. The SPICE modelled LED driver uses auxiliary voltage output to maintain the equilibrium of the system based on the feedback from the output. Simulation models report up to 95.44% efficiency.

A flyback SMPS LED driver for lighting application

The binary-based algorithms including the binary particle swarm optimization (BPSO) algorithm are proposed to solve discrete optimization problems. Many works have focused on the improvement of the binary-based algorithms. Yet, none of these works have been represented in states. In this paper, by implementing the representation of state in particle swarm optimization (PSO), a variant of PSO called multi-state particle swarm optimization (MSPSO) algorithm is proposed. The proposed algorithm works based on a simplified mechanism of transition between two states. The performance of MSPSO algorithm is emperically compared to BPSO and other two binary-based algorithms on six sets of selected benchmarks instances of traveling salesman problem (TSP). The experimental results showed that the newly introduced approach manage to obtain comparable results, compared to other algorithms in consideration.

Multi-state particle swarm optimization for discrete combinatorial optimization problem

Some machining process requires coolant to reduce the cutting temperature and helps to flush away the chips from the cutting zone. However, conventional flood coolant possesses some issues towards workers and the environment, regarding health and waste management. The implementation of Minimal Quantity Lubrication (MQL) as an alternative technique seems to be promising although the effectiveness of this technique were influenced by several factor. In turning process for instance, the distance of nozzle to the cutting zone contributes to the variation of machining performance. This study is to compare the effect on cutting performance between two internal MQL nozzle designs. The cutting tool holder were modified to have two internal MQL oil channel. The oil channel design were tested and the performance was evaluated in terms of cutting speed and cutting temperature for different cutting speed, feed rate and depth of cut. The result shows that the single channel performs better in terms of cutting force while dual channel significantly improve the cutting temperature.

Performance Investigation of Modified Turning Tool Holder for MQL Application

Electrical discharge machining (EDM) is a nonconventional milling in which holes or shape can be created without any contact between electrode and work piece during the material removal process. Throughout the machining process a series of stochastic sparks are produced when the gap between electrode and work piece is very narrow just about 10 to 50 microns. Controlling this gap in micro dimension not only depends on electrode position but also on work piece surface. So a combination of PID controller and EDM process is used to monitor the gap. In this study an indirect measurement of surface position is carried out by implementing voltage average gap model. And Simulink models have been done to simulate the dynamic behavior of EDM system.

Muhammad Arif Abdul Rahim

Papers

Model of pulse power generator in electrical discharge machining (EDM) system

A flyback SMPS LED driver for lighting application

Multi-state particle swarm optimization for discrete combinatorial optimization problem

Performance Investigation of Modified Turning Tool Holder for MQL Application

Dynamic Modeling of Electrical Discharge Machining (EDM) System Using Matlab