Abstract : This research studies the possibilities of applying unsaturated polyester coating in civil engineering. Unsaturated polyester coating is used as a polymeric material on concrete or cement mortar to improve its mechanical properties such as compressive and shear strength of concrete. Due to the brittle behavior of concrete, shear strength is one of the most important factors to be considered in structural concrete design. The model used for the geometry and loading configuration was selected to generate the shear stress state. A partially merged triplex concrete cubes is one of elements form of a shear area due to the presence of the span shear subject to direct shear force. This research focuses on describing the experimental test using samples of polyester to determine its mechanical properties. Standard concrete cubes were prepared to determine the compressive strength that concrete will withstand before and after polyester coating. As well as Partially merged triplex concrete cubes used to know the direct shear stress that the model will withstand before and after the polyester coating. This paper presents the differences between all results based on the different thicknesses of polyester coating layers on the concrete surface. The uses of unsaturated polyester with different thicknesses 13μm, 25.5μm, 38μm and 60μm as a coating on the outer surface of the concrete led to a decrease in the displacement of the concrete component by 5%, 11.4%, 20.3% and 31.8% respectively compared to samples without coating. The results showed that when using unsaturated polyester with different thicknesses of 13μm, 25.5μm, 38μm and 60μm as coating on the outer surface of concrete, the shear strength of the concrete component increased by 6%, 18%, 28% and 37% respectively Compared to samples without coating..
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Abstract : This paper discusses the virtual synchronous machine-based control of a solar photovoltaic inverter for reactive power compensation. The concept of PV-STATCOM has been proposed earlier in the literature for dynamic reactive power compensation. A PV-STATCOM provides Var support within the grid without investing in an additional dedicated inverter for reactive power compensation. The paper proposes a novel control technique for the PV-STATCOM using power swing equation-based virtual synchronous machine (VSM) control. A PLL-based DSTATCOM control is badly affected by the grid disturbances since it is basically a voltage control oscillator that depends on the instantaneous value of grid voltage. But in a VSM-based control, the reference angle is generated by a power balance-based swing equation which doesn’t depend on the grid parameters. This enhances the stability and bandwidth of the controller. The fine-tuning of the control parameter is done by modified krill herd optimization. The PV-STATCOM is modeled in the MATLAB/Simulink platform and is connected to a single-machine infinite bus system to study the transient behavior. The performance of the PV-STATCOM with VSM control was found to have a response time of 1-2 cycles during sag-swell and fault conditions..
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Abstract : The effect of various conditions of reinforced and non-reinforced AZ91 alloy on damping performance was investigated in this study. Stir casting was used to synthesize SiC and graphite particles reinforced AZ91 matrix hybrid composites with particle sizes of 25 µm. Each reinforcement quantity was modulated from 0 to 3 weight percent in increments of 1 weight percent. Then heat treatment was carried out on the hybrid composite samples (solutionized and age hardened). The heat treatment condition, weight percent of SiC and graphite particles and temperature were considered as input parameters for determining the optimum damping capacity. The experiments were conducted as per L16 Orthogonal array mixed-level approach. The test outcomes showed that the parameters have a substantial impact on the damping capacity of the composites. The damping tests on cantilever samples were performed with a Dynamic-Mechanical-Analyzer taking temperature levels in between 50-350°C. It was revealed that the optimal damping performance occurred for the heat-treated hybrid composites with increased temperature and reinforcement..
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Abstract : Companies in various industries have the desire to achieve excellence and are committed to producing quality products. The companies improve quality by adopting competitive strategies. One strategy implemented by the companies in improving product quality is to use the Six Sigma approach. This study explores related approaches for quality improvement and analyzes the impacts of the application of Six Sigma methods in various industries from articles between 2015 and 2020 from renowned journals. Selection criteria were established and used to select potential papers. 83 articles were selected based on certain predefined criteria. The major findings from this study were that around 37% of the papers showed defect reduction using various tools, compared with other factors such as processes and people. This research found that the application of Six Sigma across industries based on literature studies shows a greater impact on efficiency improvement and the smallest impact on sigma improvement..
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Abstract : Quality of osmotically dehydrated pineapples is very important to consumers. A reliable non-destructive method for assessing quality of osmotically dehydrated pineapples is required for factories in order to ensure the quality of products be-fore sending to consumers. Near infrared hyperspectral imaging (NIR-HSI) has the potential to be used for this purpose and was therefore tested for predicting qualities including hardness, total soluble solids (TSS), sulfur dioxide content (SO2) and moisture content (MC) of osmotically dehydrated pineapples. Spectra of samples were acquired in the range of 935-1720 nm and were used for estab-lishing calibration models for the quality indices by partial least squares regres-sion (PLSR). The chemometrics was investigated in order to acquire the best models. The prediction of the models for hardness, TSS, SO2 and MC had a cor-relation coefficient of prediction (Rp) of 0.86, 0.80, 0.76 and 0.84 respectively and root mean squares error of prediction (RMSEP) of 0.82 N, 1.86%, 25.53 mg/kg and 0.73% respectively. These models were also applied to samples to ob-tain predictive images that showed spatial distributions of samples quality on a color-based scale. Results showed that NIR-HSI can be applied to use as a non-destructive quality prediction method in the on-line system of factories for sorting and guaranteeing the quality of osmotically dehydrated pineapples..
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