Lack of efficient evaluation methods to help decision makers in making informed decision regarding in-house technology investments, outsourcing technology, and manual activities in the remanufacturing industry has raised serious concerns in the selection process of technologies based on company size and resources. This has resulted in the inability of decision makers to broadly assess the scope of alternative technologies against remanufacturing processes. Thus, it has resulted in the choice of a common solution based on inconsistencies and uncertainties. This paper proposes a holistic framework that can assist decision makers in evaluating the remanufacturing operations by offering better understanding of the performance and potential capabilities in the selection of appropriate technology. The salient feature of the proposed framework is its utilization of the fuzzy logic method as guiding tool to analyze criteria for technology selection in order to make informed decisions on whether to invest or outsource a technology or use labor-intensive operations to the specific process. The paper also highlights importance of the technology assessment framework in aligning and consolidating the dedicated thinking for the life cycle of the particular technology. The major contribution of the framework is its integration of obsolete and disposal phases with the acquisition and adoption phases. Therefore, during technology assessment, decision makers are guided by a step-by-step iterative process on technology requirement verification.
Sustainability is one the most crucial aspects currently focused by competitive companies who are coerced to consider their companies environmental, social and economic performance as requirements for product design. The intricate philosophy of designing physical objects, products, built environment and services to comply with the principles of social, economic and ecological sustainability is called sustainable product design. The main of this study is to improve product sustainability using Design for Six Sigma (DFSS) approach. This research primarily focuses on reviewing current sustainable product development approaches, developing a new framework to incorporate Design for Six Sigma into Sustainable Product Development and to conduct a case study on a product using this new framework. The chosen product is an electric kettle. An electric kettle is usually subjected to more extreme usage and physical damage than normal kettles. Most original internal components are very hard to come by in the replacement parts market making it a difficult product to repair and extend its life of use. The design tools used in this new framework are survey methodology, Quality Function Deployment (QFD), morphological chart and weighted rating method, SolidWorks 3D modelling and Sustainability Analysis besides DFM and DFA analysis software. Through applying the new framework under the DFSS approach a new electric kettle concept has been generated and it has been proven to be more sustainable than its predecessors proving that the new proposed framework is suitable for use in sustainable product development.
This paper presents an h-infinity robust loop shaping control and LCL filter to mitigate the effects of harmonic currents in the photovoltaic system integrated with the grid. To eliminate the negative effects of the LCL filter, this work applied notch filter active damping. Existing methods for the elimination of harmonic currents were reviewed. Proportional integral control, fuzzy logic control, h-infinity control, and robust loop shaping control are presented. The grid current was analyzed in the system with all controllers applied to control the voltage source inverter of the system to eliminate harmonics in the grid current caused by the inverter and nonlinear loads for two cases, one being constant loading of the linear and nonlinear load and another is the switching of the nonlinear load during the simulation. The results obtained from the proposed method for the two tests conducted were compared with those from other methods to prove the robustness of the proposed technique. The method manages to reduce the total harmonic distortion of the grid current from 7.85% to 0.79% for case 1 and from 11.67% to 1.14% for case 2.
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