Produced Water (PW) is the largest volume of waste that is normally generated during oil and gas production. It has large amounts of contaminants that can cause negative environmental and economic impacts. The management method for PW relies highly on types and concentrations of these contaminants, which are field dependent and can vary from one oil field to another. Produced water can be converted to fresh water if these contaminants are removed or reduced to the acceptable drinking water quality level. In addition, increasing oil production rate and reducing amounts of discharged harmful contaminants can be achieved by removing dissolved hydrocarbons from PW. In order to identify the types of these contaminants, effective tools and methods should be used. Six Sigma, which uses the DMAIC (Define- MeasureAnalyze- Improve- Control) problem-solving approach is one of the most effective tools to identify the root causes of having high percentages of contaminants in produced water. The methodology also helped develop a new policy change for implementing a way by which this treated water may be used. Six Sigma has not been widely implemented in oil and gas industries. This research adopted the Six Sigma methodology through a case study, related to the southern Iraqi oil fields, to investigate different ways by which produced water can be treated. Research results showed that the enormous amount of contaminated PW could be treated by using membrane filtration technology. In addition, a Multi Criteria Decision Making (MCDM) framework is developed and that could be used as an effective tool for decision makers. The developed framework could be used within manufacturing industries, services, educational systems, governmental organizations, and others. iv This work is dedicated to my scholarship providers and supporters wit

Over the past two decades, the Define-Measure-Analyze-Improve-Control (DMAIC) framework of the Six Sigma methodology and a host of statistical tools have been brought to bear on process improvement efforts in today’s businesses. However, a major challenge of implementing the Six Sigma methodology is maintaining the process improvements and providing real-time performance feedback and control after solutions are implemented, especially in the presence of multiple process performance objectives. The consideration of a multiplicity of objectives in business and process improvement is commonplace and, quite frankly, necessary. However, balancing the collection of objectives is challenging as the objectives are inextricably linked, and, oftentimes, in conflict. Previous studies have reported varied success in enhancing the Six Sigma methodology by integrating optimization methods in order to reduce variability. These studies focus these enhancements primarily within the Improve phase of the Six Sigma methodology, optimizing a single objective. The current research and practice of using the Six Sigma methodology and optimization methods do little to address the real-time feedback and control for online process control in the case of multiple objectives. This research proposes an innovative integrated Six Sigma multiobjective optimization (SSMO) approach for online process control. It integrates the Six Sigma DMAIC framework with a nature-inspired optimization procedure that iteratively perturbs a set of decision variables providing feedback to the online process, eventually converging to a set of tradeoff process configurations that improves and maintains process stability. For proof of concept, the approach is applied to a general business process model – a well-known inventory management model – that is formally defined and specifies various process costs as objective functions. The proposed iv SSMO approach and the business process model are programmed and incorporated into a software platform. Computational experiments are performed using both three sigma (3σ)-based and six sigma (6σ)-based process control, and the results reveal that the proposed SSMO approach performs far better than the traditional approaches in improving the stability of the process. This research investigation shows that the benefits of enhancing the Six Sigma method for multiobjective optimization and for online process control are immense.

I dagens samhälle finns ett stort behov av processeffektiviserings-metoder för att hålla företaget konkurrenskraftigt gällande produktivitet och effektivitet. Samtidigt satsar företag idag mycket på ekologisk hållbarhet, vilket har öppnat dörren för nya så kallade Green Lean-metoder vars syfte är att förbättra både produktivitet och hållbarhet. I detta arbete behandlas metoderna 5S, Environmental Value Stream Mapping, Green Lean Six Sigma samt Green Kaizen. Syftet med arbetet var att redogöra för innebörden av respektive metod samt motivera hur dessa metoder bör appliceras och implementeras i praktiken. Först behandlades metoderna teoretiskt, därefter praktiskt med enkäter. I arbetet behandlar vi företaget Scania och undersöker hur de valt att applicera och använda de metoder, hållbara metoder, de idag använder. Resultatet visade att det finns flera olika drivkrafter till varför man väljer att implementera Green Lean-metoder samt flera olika aspekter som påverkar vilka metoder som bör väljas, som exempelvis kundkrav eller erfarenhet och kunskap inom företaget. Scania använder idag Green Performance Map och Energy Kaizen som Green Lean-metoder. Slutsatsen som drogs är att metoden som bör implementeras varierar beroende på vad företaget tillverkar, hur långt de kommit med andra processeffektiviserings-metoder såsom Lean Production och Six Sigma. Om det är en problemdriven lösning så är EVSM en stark metod medan 5S bör implementeras uppifrån ledningen. / In today's society, there is a significant need for process improvement methods to maintain a company's competitiveness regarding productivity and reasonable pricing. Additionally, companies are investing heavily in environmental sustainability, leading to the emergence of new "Green Lean" methods aimed at creating improvements in both productivity and sustainability. This study examines the methods of 5S, Environmental Value Stream Mapping, Green Lean Six Sigma, and Green Kaizen. The aim of the study is to explain the meaning of each method and to motivate how these methods should be applied and implemented in practice. The methods were first studied theoretically and then practically with surveys. Scania was chosen as a case study to examine how they have chosen to apply and use the methods they have. The results showed that there are several driving forces for why companies choose to implement Green Lean methods, and several aspects affect which methods should be chosen, such as customer requirements or experience and knowledge within the company. Scania currently uses Green Performance Map and Energy Kaizen as Green Lean methods. The conclusion drawn is that the method to be implemented varies depending on what the company produces, and how far they have progressed with other process improvement methods such as Lean Production and Six Sigma. If it is a problem-driven solution, EVSM is a robust method, while 5S should be implemented by top management.

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The purpose of this research is to learn about quality measurement practices in a wood products supply chain. According to the Supply Chain Management paradigm, companies no longer compete as individual entities, but as part of complex networks of suppliers and customers, linked together by flows of materials and information. Evidence suggests that a high degree of integration between supply chain members is essential to achieve superior market and financial performance. This study investigates the potential benefits from adopting supply chain quality management practices, focusing specifically on quality measurement. A case-study was conducted to accomplish the objectives of the research. An exemplary wood products supply chain was studied in great detail. The current state was compared with best practices, as reported in the literature. Supply chain quality metrics were used to assess current performance and a simulation model was developed to estimate the impact of changes in significant factors affecting quality, such as production volume, on the supply chain's quality performance. Quality measurement practices in the supply chain of study are described in detail in this dissertation. A high degree of internal integration was observed in the focal company, attributed in great part to the leadership of management, which formulates comprehensive quality planning, specifying quality measurement practices and goals. These practices provide the company with a competitive advantage, and have undoubtedly contributed to its relatively strong market share and financial performance. Significant improvements in defect rate and on-time performance at all levels in the supply chain have been achieved in great part thanks to current initiatives. There is room for improvement, however, regarding external integration; the supply chain of study could benefit from more information sharing with its external suppliers and increasing its supplier development efforts. There is also a lack of true measures of supply chain quality performance that could facilitate tracing variances back to their origin upstream the supply chain. Supply chain metrics must reflect the contribution of each supply chain member to the overall performance, and span the entire supply chain. This is the first study that looks in depth at quality measurement practices from a supply chain perspective. It is also one of very few studies of supply chain management applied to the wood products industry. Examples are presented of how a supply chain performance measurement system can be developed. Results from this research show that it is important to adopt a supply chain perspective when designing a performance measurement system, not least to avoid sub-optimization. Poor quality at any point in the supply chain eventually translates into higher prices for the final customer, is detrimental to customer dissatisfaction, and hurts profitability; with the end result of declining competitiveness of the entire system. / Ph. D.

With lower output voltage (lower than 1V) and higher output current (more than 160A) required in the near future, the voltage regulators for the microprocessors, a kind of special power supplies are facing more and more critical challenges to achieve high efficiency and high power density. 90% plus efficiency for CPU VRs is expected from industry not only for the thermal management, but also for saving on electricity costs, especially for the large data-center systems. At the same time, high power density VRs are also desired due to the increasing power consumption of microprocessors as well as the precious space on CPU motherboard. Current multi-phase Buck VR has its limitation to achieve 90% plus efficiency. With the state of art devices, the single-stage 12V/1.2V 600kHz Buck VR achieves 85% to 86% efficiency at full load condition. In addition, for the future lower output voltage application, the Buck efficiency will drop another 3~4% due to the extreme small duty cycle. From the power density point of view, due to the switching frequency limitation (normally, from 300 kHz to 600 kHz for typical CPU VRs) for acceptable efficiency performance, the multi-phase Buck VR is unable to ensure a small size since it needs bulky output capacitors to meet the challenging transient requirement as well as the output impedance requirement with relatively low bandwidth design. To attain high efficiency and high power density at the same time, in-series two-stage power architecture was proposed. By cutting the single stage into two and utilizing the low voltage devices, the in-series two stages can achieve around 87% efficiency which is similar as single stage with second-stage operating at 1 MHz for less cost. Compared with the in-series one, the other two-stage power architecture is called "Sigma" architecture which is composed by an unregulated converter (DCX) and a regulated buck converter, with a special connection where the inputs are in series while outputs are paralleled. Through this topology, unlike the in-series two-stage where both two stages deliver the full load power, the power will be distributed between unregulated DCX and regulated Buck. If the unregulated DCX can achieve high efficiency, let most power be handled by it and just small power from buck, the Sigma architecture can achieve high efficiency performance based on this concept. The design consideration and process had been investigated by CPES previous graduates. By the designed 1.2V/120A Sigma VR circuit, approaching 90% efficiency was achieved which is around 3~4% efficiency higher than state of the art multi-phase Buck VR. However, it is not the optimal design for best efficiency performance, the improvement methods for higher efficiency is deeply considered and the efficiency potential benefit of this special structure will be clarified in this thesis. Besides the efficiency interest, transient performance of Sigma VR is also a challenging issue needed to be addressed. The state of the art Buck VR needs a bunch of output bulk capacitors to meet the stringent output impedance requirement from Intel and those output bulk capacitors occupy too much space in the motherboard. For Sigma architecture, through the help of the low impedance DCX which can achieve faster current dynamic response, some low voltage bulk capacitors could be replaced by smaller input high voltage capacitors. It is still not clear for us to identify how input capacitor impacts the DCX dynamic current response and how to best choose this impact factor. This thesis will investigate the faster DCX dynamic current performance of Sigma VR, and explain the dynamic impacts from input capacitors, from control design and from DCX impedance Lout. The high voltage capacitors could provide energy through low impedance DCX to deal with the transient load with smaller capacitance, resulting less total cost and footprint with conventional Buck solution. Low impedance DCX is also a desire for achieving fast current response for providing a "non-obstacle" path when energy transferring from input capacitors. The control also has the impact to the DCX current response when the bandwidth is higher than certain frequency. The transient benefit will also be discussed from impedance perspective. In order to improve the efficiency and power density of Sigma VR, several methods are proposed. As a critical component of DCX, the transformer design determines the performance of Sigma VR both to efficiency and power density. By optimizing the transformer design to achieve lower winding loss and smaller leakage inductance, the higher efficiency and faster transient DCX can be obtained. Changing the output capacitors to ceramic ones is helpful when control bandwidth is greater than 100 kHz for both lower cost and smaller footprint. Continually pushing bandwidth can reduce the required output ceramic capacitor number further. In addition, from the study of the loss breakdown, by adjusting the energy ratio of DCX and Buck can achieve higher efficiency based on current device level. What is more, with the same simple concept of adjusting power ratio of DCX and Buck, with the development of devices in the future as well as higher efficiency DCX, Sigma architecture will be more attractive for future's lower output voltage VR application. And it will also be more efficient considering higher than 12V input bus voltage by letting high efficiency DCX handle more power. Utilizing this characteristic, changing the power system delivery architecture from AC input to the microprocessors, the end to end efficiency could be improved. / Master of Science

[pt] O Lean Six Sigma (LSS) vem impulsionando diversas organizações ao redor do mundo, aprimorando seus negócios através da melhoria de qualidade e de desempenho. Diversos estudos apontam os resultados esperados pela abordagem LSS depende do sucesso do processo de implementação. Embora existam alguns frameworks que guiem as organizações no processo de implementação, poucos estudos consideram as especificidades dos sistemas produtivos Engineer-to-Order (ETO). Esta dissertação de mestrado se propõe a preencher essa lacuna desenvolvendo um framework de implementação desenvolvido em Pesquisa-Ação. Para isso, foi utilizado um modelo de maturidade híbrido cujos principais parâmetros são os Fatores Críticos de Sucesso (FCS). O modelo e os parâmetros foram levantados e explorados na literatura por meio de Revisões de Escopo. Para refletir e avaliar o contexto ETO, esses parâmetros foram validados, estruturados e ponderados por grupos focais de especialistas, através dos métodos Item-Objective Congruence (IOC), Analytic Hierarchy Process (AHP) e a estatística Kappa de Fleiss. Em seguida, uma Pesquisa-Ação foi realizada junto a uma empresa do setor midiático, perseguindo ciclo checkaction-plan-do (CAPDo). Como resultado, a organização direcionou seus esforços de melhoria contínua, resultando no rápido aumento do nível de maturidade. Essa pesquisa exploratória deu origem um framework apresentado como um guia de implementação LSS para organizações ETO. Algumas oportunidades de melhoria e limitações, como a subjetividade da ferramenta de avaliação e a necessidade de novas aplicações práticas, que requerem tempo, são indagadas como sugestões de melhoria para pesquisas futuras. / [en] Lean Six Sigma (LSS) has been driving many organizations around the world, enhancing their business through quality and performance improvement. Several studies point out the results expected from the LSS approach depend on successful implementations. Although there are some frameworks that guide organizations through the implementation process, few studies consider the specifics of Engineer-to-Order (ETO) production systems. This master dissertation proposes to fill this gap by developing an implementation framework developed in Action Research. For this, a hybrid maturity model was used, whose main parameters are the Critical Success Factors (CSF). The model and parameters were identified and explored in the literature through Scoping Reviews. To reflect and evaluate the ETO context, these parameters were validated, structured and weighted by focus groups with experts using Item-Objective Congruence (IOC), Analytic Hierarchy Process (AHP) methods and Fleiss Kappa statistic. Next, a Research-Action was conducted within a media sector company, pursuing the check-action-plan-do (CAPDo) cycle. As a result, the organization directed its continuous improvement efforts, resulting in a rapid increase in maturity level. This exploratory research gave rise to a framework presented as an LSS implementation guide for ETO organizations. Some opportunities for improvement and limitations, such as the subjectivity of the assessment tool and the need for further practical applications, which require time, are inquired as improvement suggestions for future research.