7,507 research outputs found

    Biopsychosocial Assessment and Ergonomics Intervention for Sustainable Living: A Case Study on Flats

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    This study proposes an ergonomics-based approach for those who are living in small housings (known as flats) in Indonesia. With regard to human capability and limitation, this research shows how the basic needs of human beings are captured and analyzed, followed by proposed designs of facilities and standard living in small housings. Ninety samples were involved during the study through in- depth interview and face-to-face questionnaire. The results show that there were some proposed of modification of critical facilities (such as multifunction ironing work station, bed furniture, and clothesline) and validated through usability testing. Overall, it is hoped that the proposed designs will support biopsychosocial needs and sustainability

    Modeling and Optimization of a Novel Chilled Ammonia Absorption Process and Amine-Appended Metal-Organic Frameworks for CO2 Capture

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    Post-combustion capture is one of the leading technologies for CO2 abatement from anthropogenic sources which have contributed significantly to the rise of atmospheric greenhouse gases. Specifically, solvent-based capture post-combustion processes are the industry standard but can suffer drawbacks such as high energy penalties and corrosion. In this work, two possible improvements are investigated which have been recently proposed in the literature. The first is aqueous ammonia as a capture solvent which has been shown to have several advantages including, but not limited to, a lower regeneration energy. The second is a novel solid sorbent, an amine-appended metal-organic framework (MOF). The MOF exhibits several promising attributes, namely, a step-shaped adsorption isotherm which leads to lower working capacities and lower regeneration energies when compared to traditional solid sorbents. The overall goal of this work is to develop rigorous mathematical models which can be used for process design and economic evaluation of these technologies. First, an integrated mass transfer model is developed for the chilled ammonia process (CAP). This model is developed using a simultaneous regression approach that has been recently proposed in the literature with parameter estimation performed using data from a pilot plant source and wetted-wall column. The optimally estimated parameters are shown to have a lower prediction error to validation data than parameters found in literature. The integrated mass transfer model is then used to develop a model for a novel chilled ammonia process. The process includes a NH3 abatement system which utilizes a reverse osmosis membrane to aid in separation and reduce the energy penalty. Simulation of the process shows that the membrane can significantly reduce the energy requirement of the reboiler, condenser, and cooler in the abatement section. Uncertainty of the estimated mass transfer parameters is quantified using a fully Bayesian approach which is demonstrated to show a significant reduction in the prediction uncertainty of key process indicators. Second, isotherm and kinetic models are developed for amine-appended MOFs, dmpn-Mg2(dobpdc) and Mg2(dobpdc)(3-4-3). The step-shaped adsorption isotherms exhibited by these MOFs present a modeling challenge since many of the traditional isotherm models are unable to capture step transitions. Three isotherm models are examined in this work, a weighted dual-site Langmuir model found in literature, a dual-site Sips model developed in this work, and an extended weighted Langmuir model also developed in this work. Parameter estimation is performed using available isotherm data and it is shown that the models are able to predict the CO2 adsorption data well. A kinetic model is then developed using a linear driving force for mass transfer which does an excellent job at predicting time dependent TGA data. An additional goal of this work is development of a chemistry-based model for functionalized solid sorbents that aims to capture the underlying adsorption reaction mechanisms which are not typically considered in solid sorbent modeling. As part of this model, optimal reaction set selection is performed since the reaction pathways for dmpn-Mg2(dobpdc) are still relatively unknown. Parameter estimation is performed, and it is found that the chemistry-based model significantly outperforms the Sips isotherm model with regards to prediction error and other model building criteria. To aid in the evaluation of the commercial feasibility of the MOF, equation-oriented mathematical models for a fixed bed contactor and moving bed contactor are developed. The contactors are then to simulate industrial scale CO2 capture process for coal based and NGCC based flue gas. Using developed cost models, techno-economic analysis and optimization of these processes is then performed and it is found that efficient thermal management can make these MOFs viable alternatives for CO2 capture processes

    SIMULATING CONSUMABLE ORDER FULFILLMENT VIA ADDITIVE MANUFACTURING TECHNOLOGIES

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    Operational availability of naval aircraft through material readiness is critical to ensuring combat power. Supportability of aircraft is a crucial aspect of readiness, influenced by several factors including access to 9B Cognizance Code (COG) aviation consumable repair parts at various supply echelons. Rapidly evolving additive manufacturing (AM) technologies are transforming supply chain dynamics and the traditional aircraft supportability construct. As of June 2022, there are 595 AM assets within the Navy’s inventory—all for research and development purposes. This report simulates 9B COG aviation consumable fulfillment strategies within the U.S. Indo-Pacific sustainment network for a three-year span, inclusive of traditional supply support avenues and a developed set of user-variable capability inputs. Simulated probabilistic demand configurations are modeled from historical trends that exploit a heuristic methodology to assign a “printability” score to each 9B COG requirement, accounting for uncertainty, machine failure rates, and other continuous characteristics of the simulated orders. The results measure simulated lead time across diverse planning horizons in both current and varied operationalized AM sustainment network configurations. This research indicates a measurable lead time reduction of approximately 10% across all 9B order lead times when AM is employed as an order fulfillment source for only 0.5% of orders.NPS Naval Research ProgramThis project was funded in part by the NPS Naval Research Program.Lieutenant Commander, United States NavyApproved for public release. Distribution is unlimited

    Reuse : first international working seminar, Eindhoven, November 11-13, 1996 : proceedings

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    Reuse : first international working seminar, Eindhoven, November 11-13, 1996 : proceedings

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    RFID in Healthcare: A Six Sigma DMAIC and Simulation Case Study

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    Develop a business model to generate quantitative evidence of the benefits of implementing Radio Frequency Identification (RFID) technology limiting the scope to outpatient surgical processes in hospitals. Analysis showed significant estimated annual cost and time savings in carrying out patients’ surgical procedures with RFID technology implementation for the outpatient surgery processes in a hospital. This is largely due to elimination of both the non-value added activities of locating supplies and equipment and also the elimination of the “return” loop created by preventable post-operative infections. Several poka-yokes developed using RFID technology were identified to eliminate those two issues, as well as, for improving the safety of the patient and cost effectiveness of the operation to ensure the success of the outpatient surgical process. Several poka-yokes developed using RFID technology were identified for improving the safety of the patient and cost effectiveness of the operation to ensure the success of the outpatient surgical process

    Improving Healthcare Logistics Processes

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    Closing Loops in Supply Chain Management: Designing Reverse Supply Chains for End-of-Life Vehicles.

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    In this thesis, the focus is on the design of reverse supply chains for end-of-life products, in particular end-of-life vehicles. For long-term success of end-of-life management, more economic stimuli are needed than is currently the case. Legislation as a single driving force is insufficient for companies to achieve closed loop supply chains. The key issue is to find eco-efficient solutions, i.e. design and operate an economically low cost network without violating applicable targets imposed by environmental legislation. In this thesis, a case study research methodology is adopted to develop design principles for network design and assess the consequences on the operations research models. Three case studies, which stem from the network of Auto Recycling Nederland, are described in detail.

    Extending the Decision-Making Capabilities in Remanufacturing Service Contracts by Using Symbiotic Simulation

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    Remanufacturing is a critical enabler of a resource efficient manufacturing industry that has long been associated with high value products. Over time, the commercial relationship between customers and service providers has been made through the fulfilment of rights and obligations under remanufacturing service contracts. Nonetheless, financial analysis to evaluate the contract terms and conditions are becoming increasingly difficult to conduct due to complex decision problems inherent in remanufacturing systems. In order to achieve better and safer decision-making to shape the business strategies, remanufacturers often employ computer-based simulation tools to assess contractual obligations and customers’ needs. This paper discusses the roles of a symbiotic simulation system (SSS) in supporting decision-making in remanufacturing systems. An industrial case study of power transformer remanufacturing illustrates how SSS can support contract remanufacturers in managing service contracts planning and execution. By linking the simulation model to the physical system, it has been demonstrated that the capabilities of the remanufacturers to make critical decisions throughout the entire service contract period can be extended

    Closing the Loop: Exploring IKEA’s Transition to the Circular Economy

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    Inspired by the way nature cycles waste in an ecosystem, the circular economy was developed as an alternative to the linear take-make-dispose model and designed to decouple economic growth from resource use. After developing a framework for what it means to be a business pursuing circularity, this thesis examines six different companies to explore the tension between the strategies and business models in theory and what business are implementing in practice today. This exploration continues with an in-depth analysis of the circular success of IKEA, finding that the gains from the circular economy for a large corporation are found within their own operations. With the company’s scale, IKEA is able to act as a transfer hub of technology and best practices, ultimately allowing the company to make a global impact
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