Browsing by Subject "Engineering Management"

Now showing 1 - 8 of 8
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    An Assessment and Simulation Methodology of Sustainability in Manufacturing System
    (2018-06) Islam, Md
    This thesis work presents a new integrated framework to connect the economic, environmental and social factors, and to analyze sustainability performance of the system by balancing these factors. Sustainable manufacturing systems should be profitable and environmentally friendly while being safe both physically and socially for everyone in the system. This thesis work highlights the main aspects and requirements of sustainability, which are related to manufacturing systems, demonstrating that there are other aspects of sustainability in general that are not reflective on manufacturing. This work also highlights many useful assessment indices of manufacturing sustainability, which makes quantification, and then comparison and optimization of system performance possible. A comparative study on the existing sustainability assessment tools is performed to classify these tools based on appropriateness to manufacturing systems and limitations by reviewing the significant research work in system modeling for assessing and optimizing manufacturing sustainability. The review has revealed that the triple bottom line TBL factors, economic, social and environmental, are difficult to evaluate and optimize simultaneously due to the complex nature of manufacturing systems and the wide variety of processes and type of the system. Furthermore, the review has demonstrated that there is significant research gap in considering social sustainability for overall sustainability characterization. The consideration and the integration of social sustainability with other factors make this framework unique and more functional. Three case studies have been conducted to understand the applicability of this novel framework. The first case study reveals the difficulties associated with achieving social sustainability as most of the parameters in social sustainability are intangible in nature that’s why it is difficult to optimize the parameters associated with social sustainability. The last two case studies are analyzed to evaluate the sustainability in oil and gas industry with the help of fuzzy interference modelling. Fuzzy interference modelling is the core unit of decision making and mathematical reasoning of the sustainability assessment simulation, when the outcomes are uncertain. The modelling is built with the help of triangle membership functions to fuzzify the variables. Fuzzy rules like ‘IF THEN’ along with operators “OR” or “AND” then come into play for generating necessary decision rules. In this work, these decision rules aggregately simulate and generate the overall sustainability assessment results for case studies 2 and 3. All case studies strongly demonstrate the pragmatic and facile application of the proposed framework to assess the overall sustainability in continuous manufacturing context. Finally, the scope of future research work is also presented for the proposed novel framework.
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    Computational and experimental study of an active noise cancellation system for impulsive noise.
    (2011-07) Li, Peng
    Control of impulsive noise is one important challenge for the practical implementation of active noise control (ANC) systems. The advantages and disadvantages of the popular filtered-X least mean square (FXLMS) ANC algorithm and nonlinear filtered-X least mean M-estimate (FXLMM) algorithm are discussed in this paper. A new modified FXLMM algorithm is also proposed to achieve better performance in controlling impulsive noise. A hardware-in-the-loop experiment platform is built using the dSPACE system. Also, computer simulations and experiments are carried out for all three algorithms and the results are presented and analyzed. The results show that the FXLMM and modified FXLMM algorithms are more robust in suppressing the adverse effect of sudden large amplitude impulses than the FXLMS algorithm, and in particular, the proposed modified FXLMM algorithm can achieve better stability without sacrificing the performance of residual noise when encountering impulses.
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    Exploring critical factors for successful closed-loop supply chains with remanufacturing
    (2012-06) Turner, Kyle John
    This thesis contributes to the knowledge on closed-loop supply chains (CLSC) with a focus on remanufacturing in the fields of sustainability. CLSCs involve the collection of end-of-life products, the remanufacturing of these products to original specifications, and the redistribution of remanufactured products. The objective of this research is to identify factors key to the success of CLSCs with remanufacturing practices and to propose a business model framework for remanufacturing companies. Through case studies on several companies in the consumer electronics, heavy equipment manufacturing, and industrial process control industries, issues related to product safety, liability, reliability, customer perception, and others are analyzed. Within the company environment, it is important to address the mission and vision statements, the project portfolio, and acquisitions, partnerships, or mutual agreements with other businesses; within the product environment, it is important to address the intellectual property of product design, product acquisition and reverse logistics, and design for remanufacturing; within the macro environment, it is important to address the industry’s technology clockspeed, regulatory agencies, and customer perception of remanufactured products. These factors are identified to be critical to the success of CLSCs. To address the challenges faced by remanufacturing companies, such as the lack of awareness and knowledge of remanufacturing throughout the world, possible solutions are proposed. Findings from this study are important to engineering management research and practice because the growing concerns on the environment and sustainability will bring an increased focus on these issues in the near future.
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    Exploring the impact of lean design and lean supply chain management on an organization’s innovation capability.
    (2010-06) Taylor, Ryan Douglas
    This thesis analyzes and discusses how implementing lean design and lean supply chain management affect an organization’s innovation capabilities. Since lean concepts focus on low risk, short-term gradual improvement of existing processes and products with an emphasis on eliminating any and all wastes in the system, applying lean to an organization often implies difficulties in promoting innovations that involve high risks and dramatic changes. Little is known about how lean design and lean supply chain management concepts might affect an organization’s innovation capability and its responsiveness to react quickly to changes brought by radical innovations. These relationships were investigated and analyzed based on findings from two online surveys. Seventy-six and seventy-seven respondents were acquired from the two surveys, respectively. Results suggest that the stressed importance of standardization in lean design has a negative effect on an organization’s radical and architectural innovation capability. It is also shown that disruptive innovation capability will be negatively influenced by value analysis in lean design, especially in terms of how an organization ranks product attributes and allocates resources based on customer requirements. For the impact on an organization’s responsiveness to radical innovations, the findings suggest no impact from minimizing buffers in a lean supply chain but a positive impact from increasing supplier commitment and involvement levels.
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    Feasibility study on the utilization of soybean oil and butanol blends as an alternative fuel source for combustion applications
    (2012-12) Schoo, Reilly Jay
    A variety of concepts have been investigated in an effort to categorize simply mixed blends of soybean oil-butanol fuel as a suitable alternative fuel source for combustion applications. Basic physical property testing carried out in accordance with ASTM standardized methods proved that the addition of butanol to the highly viscous soybean oil (SBO) lowered viscosity, density, and surface tension and improved cold flow properties. The high energy density of pure SBO proved to increase the heating value of the fuel blend. Mixing rules and estimation methods were developed to predict basic property values as a function of temperature and composition with good accuracy. Evaporation studies on single fuel droplets revealed that there is a diffusion-like gasification mechanism present when SBO/butanol blends are exposed to pure vaporization at or below 225°C. All blends exhibit evaporation constants similar to pure butanol suggesting that the mass diffusion of butanol toward the surface is faster than the surface regression rate of the droplet. Combustion tests results suggested that there is a mixed mode gasification mechanism dominated by that of a diffusion rate limiting one present during combustion of single SBO/butanol droplets. Disruptive burning and microexplosions occur because of the mass diffusion of butanol toward the droplet surface being slower than that of the surface regression during combustion. This results in the trapping of butanol within the surface of the droplet allowing for it to be superheated and causing obliteration of the fuel droplet. All blends proved to exhibit incomplete combustion however it was less likely for droplets of near equal concentrations. Blends of near equal concentration (Bu50 and Bu40) proved to have a higher tendency for microexplosions to occur and they were more violent. Strategic droplet size measurements throughout their lifetime provided insight that this is likely due to the amount of butanol burned prior to droplet microexplosions. An economical analysis provided information suggesting that simply mixed SBO/butanol blends could be a feasible alternative fuel source for various combustion applications.
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    Hydraulic Regenerative Vehicle Suspension
    (2010-12) Hedlund, Jason David
    This paper looks into the feasibility of a hydraulic regenerative suspension system for vehicles. The linear motion from vehicle vibration is converted into rotational motion by using a double-acting hydraulic cylinder, a hydraulic motor and associated hydraulic system. The rotational motion drives an electrical generator, converting mechanical energy into electrical energy. The energy recovery system was designed, constructed, and tested in lab and on an all-terrain-vehicle (ATV). While the average power output and efficiency were not as high as expected, several paths for future improvement were discovered. It appears that the sizing of components in this small scale system is critical to achieve more desirable power outputs and efficiencies.
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    Life cycle assessment and economic aspects of laterally integrated solar cell.
    (2011-03) Singh, Siddharth Rammurti
    Sustainable development requires use of many different methods and tools to measure performance with regards to environmental impact. Environmental impact counts for both the emission from the system and also the emission during the manufacturing of the system. The standards for solar cells are given in the ISO 14000 series. ISO standards can only be used for solar systems that are in service. This paper will try to analyze a system which is in its design phase by combining the ISO 14000 series with a quantitative approach from simplification of process-LCA. At the same time it will also try to compute the economics behind the new design to generate a sustainable design. This study is done to analyze the design phase only and to identify any possibility of improvement. This paper also tries to identify the effect of solar insolation on the output of the solar cell. The design that will be analyzed is called a laterally integrated solar cell. In this design, the semiconductors are laterally assembled. Laterally integrated photovoltaic cell design technology is intended as a substitute for a traditional photovoltaic cell offering higher efficiency, lower cost, minimal maintenance and most importantly sustainability. This paper considers energy flows from cradle to gate starting from silica extraction to the final panel assembly. The after use or recycle phase is not considered because this study is intended to understand the design phase and its environmental impacts. The different semiconductors used for this technology include Indium Gallium Nitride (InGaN), Polycrystalline-Si, Amorphous-Si, and Cadmium Telluride (CdTe). The most critical phase is the transformation of extracted raw material into a 99.999% pure form to be used in the production of solar cells. Maximum power point (Pm) and Energy Payback Time (EPBT) have been evaluated, considering different geographic locations with the use of relevant real time values of solar radiation, latitude, longitude and elevations. Evaluation of an existing solar panel system located at UMD as compared to a laterally integrated PV solar panel is also performed. It was concluded from the study that the energy payback time of the system is comparatively higher than other systems present in the market. Solar insolation also plays a big role in the output of the solar system. The difference between the maximum and minimum EPBT of laterally integrated systems at different locations across the globe was about 7.4years. Levelized cost of energy of the system is around $247/MWh. It is very high compared to other conventional and non-conventional energy sources. The factor that supports the design is the present worth of electric power the system will generate over its entire life of 30 years. System results were promising when compared with the University of Minnesota-Duluth solar panel. A laterally integrated system, if substituted for the panel at UMD, will generate 19438.53kWh of electricity and save 12370.68 kg of CO2, 48.60 kg of NO2, and 69.98 kg of SO2 within 18 months of its service.
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    Software implementation of hierarchical decision modeling and hierarchical decision modeling sensitivity analysis.
    (2011-12) Mahmood, Adnan
    Decision making can be regarded as the mental processes (cognitive process) resulting in the selection of a course of action among several alternative scenarios. Every decision making process produces a final choice. The output can be an action or an opinion of choice. To facilitate multi-criteria multi-level decision makings, different algorithms including the Hierarchical Decision Modeling (HDM) and its Sensitivity Analysis (HDM SA) have been developed. This research project implements the HDM and HDM SA algorithms developed by Dr. Dundar F. Kocaoglu and Dr. Hongyi Chen in software application to ease the cognitive burden of the users and assist decision makers in effective decision making. The project is carried out from the conception stage to the final manifestation of the software in a planned and structured process. Its application is demonstrated through two examples, one using a complete hierarchy to assess technologies and the other using an incomplete hierarchy to create a technology development envelope. A user guide of the software application is included at the end of this thesis.