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Millerd, Paul M. B. A. Massachusetts Institute of Technology. „Driving cycle time reduction through an improved material flow process in the electronics assembly manufacturing cell“. Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/73395.
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Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division; in conjunction with the Leaders for Global Operations Program at MIT, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 62).
Many companies have implemented lean and six sigma programs over the past twenty years. Lean has been a proven system that has eliminated waste and created value at many companies throughout the world. Raytheon IDS's lean program, "Raytheon Six Sigma" became a top priority in the past ten years at the Integrated Air Defense Center (IADC) in Andover, MA. However, as Raytheon's corporate goals state, they want to take this further and bring "Raytheon Six Sigma" to the next level, fully engaging customers and partners. A focus of this continuous improvement effort was the Electronics Assembly Rack manufacturing cell, which was experiencing high levels of cycle time variability. To help reduce cycle times within the cell, a continuous improvement project was undertaken to improve the material flow process. A current state analysis of the process showed an opportunity to improve process standardization and prioritization while lowering inventory levels. In addition to working with managers from EA to evaluate the material flow process, a kitting cart was developed with a cross functional project team to serve as a tool to help improve the process. Although the improvements were not rolled out to the entire cell during the project, a successful pilot was conducted that helped improve engagement with operators and create a path for future success.
by Paul Millerd.
S.M.
M.B.A.
2
Lundström, Jonathan, und Emil Hörnberg. „Rotator assembly at Indexator“. Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-64058.
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The thesis is concerning rotator assembly at Indexator. A need to increase production has been seen and it can be done by implementing an optimized assembly process. In addition to the assembly process a new design on workstations and new test equipment is needed.The study resulted into three assembly process proposals. The processes were balanced, layouts were produced and Plant simulation was utilized to produce simulation models. Each proposal were analyzed based on cost, performance, ease of implementation, flexibility and worker condition. This resulted in a stationary assembly process being most promising and a 3D simulation model was produced for visualization and better understanding. The stationary assembly process has a capacity for 90 rotators per day, while reducing the amount of workers by one.The layout of the workstations was done based on the assembly process layout and further developed to make the work cell lean and ergonomic. It resulted in three workstations to perform the assembly. The test bench was developed by creating target specifications, establish a test procedure and decide components for the test bench layout. The finished test bench can measure dynamic torque, count particles to ensure cleanliness and is able to run the test unattended.Examensarbetet handlar om montering av rotatorer på Indexator. Målet är att ta fram en optimerad monteringsprocess som kan implementeras i Indexators fabrik utan svårigheter. Den nya monteringsprocessen kommer kräva en ny design på arbetsstationerna och nya testbänkar.Fyra koncept på monteringsprocessen togs fram, baserat på monteringens behov och målsättning. Efter utvärdering så modifierades de fyra koncepten till tre förslag på monteringsprocesser. Processerna balancerades, layouter utvecklades och simuleringsmodeller producerades för varje process. Varje förslag analyserades baserat på kostnad, prestanda, implementation,flexibilitet och arbetar-förhållande. Resultatet blev en stationär monteringsprocess och en 3Dsimulering gjordes för visualisering och förståelse. Den stationära monteringsprocessen har en kapacitet på 90 rotatorer per dag och reducerar behovet av montörer.Layouten för monteringsstationerna baseras på processens layout och har modifierats för ergonomiska aspekter. Inom monteringsstationerna så utvecklades layouten för att minimera antalet onödiga rörelser för montören. Testriggens design utvecklades genom att analysera de behov som fanns, skapa en kravspecifikation samt utvärdera och besluta om testprocedur, upplägg för testrigg och dess ingående komponenter. Testriggen uppfyller målsättningen som är att kunna mäta dynamiskt vridmoment, räkna partiklar för att säkerställa renhet i rotatorn och kunna utföra testningen självgående för att frigöra montören under testprogrammet.
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Mostafaee, Mani. „Six Sigma for quality assurance of Lithium-ion batteries in the cell assembly process : A DMAIC field study at Northvolt“. Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-85966.
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Lack of technical cleanliness and particle contaminations in Lithium-ion battery manufacturing affect the performance of batteries which are a risk for the safety and quality of the product. Therefore, part of the manufacturing process occurs inside the Clean and Dry room area to maintain technical cleanliness. This paper aims to provide a framework to control particle contamination inside the Clean and Dry room and strengthen the product's quality and safety. A literature study was conducted, which was completed by a field study at Northvolt Labs in Västerås to achieve the study's aims. The study contributes to existing theories by providing a framework to find root causes of particle contamination in the manufacturing process based on the existing literature and standards. The Six Sigma problem-solving methodology DMAIC was implemented to conduct the field study. A risk assessment was conducted to find the possible threats toward technical cleanliness in the cell assembly process. The risk sources were identified by implementing measurement methods from relevant standards. The results indicate a high risk for technical cleanliness are coming from the decontamination method, material, machines, and environment. Furthermore, several recommendations were given that are expected to decrease the amount of nonconformity in the process.Brist på teknisk renhet och partikelföroreningar vid tillverkning av litiumjonbatterier påverkar dess prestanda och utgör en risk för produktens säkerhet och kvalitet. Därför sker en del av tillverkningsprocessen i ett Clean & Dry rum för att upprätthålla teknisk renhet. Denna uppsats syftar till att ge ett ramverk för att kontrollera partikelföroreningar och därmed stärka produktens kvalitet och säkerhet. För att uppnå syftet genomfördes först en litteraturstudie vilket vidare kompletterades med en fältstudie vid Northvolt Labs i Västerås. Studien bidrar till befintliga teorier genom att tillhandahålla ett ramverk för att hitta och åtgärda rotorsaker till partikelkontaminering i tillverkningsprocessen baserat på befintlig litteratur och standarder. Sex Sigma problemlösningsmetoden DMAIC implementerades för att genomföra fältstudien. En riskbedömning genomfördes för att hitta riskfyllda aktiviteter i processen. Vidare implementerades mätmetoder från relevanta standarder för att mäta kontamineringsnivån. Resultaten indikerar stor risk för tekniskrenhet från saneringsmetoder, material, maskiner och miljön. Vidare rekommenderas flera åtgärder för att underhålla tekniskrenhet vilka förväntas minska avvikelser i processen.
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von, Unwerth Thomas, und Welf-Guntram Drossel. „FC³ - 1st Fuel Cell Conference Chemnitz 2019 - Saubere Antriebe. Effizient Produziert.: Wissenschaftliche Beiträge und Präsentationen der ersten Brennstoffzellenkonferenz am 26. und 27. November 2019 in Chemnitz“. Universitätsverlag Chemnitz, 2019. https://monarch.qucosa.de/id/qucosa%3A35720.
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Die erste Chemnitzer Brennstoffzellenkonferenz wurde vom Innovationscluster HZwo und dem Fraunhofer-Institut für Werkzeugmaschinen und Umformtechnik IWU durchgeführt. Ausgewählte Fachbeiträge und Präsentationen werden in Form eines Tagungsbandes veröffentlicht.The first fuel cell conference was initiated by the innovation cluster HZwo and the Fraunhofer Institute for Machine Tools and Forming Technology. Selected lectures and presentations are published in the conference proceedings.
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Tse, Laam Angela. „Membrane Electrode Assembly (MEA) Design for Power Density Enhancement of Direct Methanol Fuel Cells (DMFCs)“. Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11522.
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Micro-direct methanol fuel cells (micro-DMFC) can be the power supply solution for the next generation of handheld devices. The applications of the micro-DMFCs require them to have high compactness, high performance, light weight, and long life. The major goal of this research project is to enhance the volumetric power density of direct methanol fuel cells (DMFCs). A performance roadmap has been formulated and showed that patterning the planar membrane electrode assembly (MEA) to 2-D and 3-D corrugated manifolds can greatly increase the power generation with very modest overall volume increases. In this project, different manufacturing processes for patterning MEAs with corrugations have been investigated. A folding process was selected to form 2D triangular corrugations on MEAs for experimental validations of the performance prediction. The experimental results show that the volumetric power densities of the corrugated MEAs have improved by about 25% compared to the planar MEAs, which is lower than the expected performance enhancement. ABAQUS software was used to simulate the manufacturing process and identify the causes of deformations during manufacture. Experimental analysis methods like impedance analysis and 4 point-probes were used to quantify the performance loss and microstructure alteration during the forming process. A model was proposed to relate the expected performance of corrugated MEAs to manufacturing process variables. Finally, different stacking configurations and issues related to cell stacking for corrugated MEAs are also investigated.
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Siegel, Frank. „Tiefdruckverfahren zur Herstellung von Katalysatorschichten für (PEM) Brennstoffzellen“. Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-203816.
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Diese Dissertation befasst sich mit der industrienahen Herstellung von Katalysatorschichten für Polymer-Elektrolyt-Membran-Brennstoffzellen mit Hilfe des Tiefdrucks als Fertigungsverfahren. Um die Anforderungen an die Katalysatorschicht hinsichtlich der Schichtdicke zu erreichen, wird ein Linienraster für den Tiefdruck entwickelt. Das patentierte und verifizierte Designkonzept des Linienrasters ermöglicht es, trotz Tinten mit geringem Feststoffgehalt hohe Trockenschichtdicken zu erzeugen. Aufgrund des verwendeten Tiefdruckrasters sind Optimierungsschritte an der Fertigungsanlage notwendig, um eine hohe Schichtqualität zu erreichen. Schließlich werden kontinuierlich und industrienah Katalysatorschichten gefertigt, die als Membran-Elektroden-Einheit in einer Polymer-Elektrolyt-Membran-Brennstoffzelle erfolgreich eingesetzt werdenThis work presents an industrial close manufacturing process of active electrodes for Polymer Electrolyte Fuel Cells utilizing an adapted gravure printing process. To meet the requirements of the electrodes regarding the layer thickness (weight) and quality a novel line screen with maximized dipping volume for gravure printing was developed and investigated. A design rule for this kind of screens was realized and verified by a successful manufacturing of electrodes with different dried layer thicknesses. Due to the rough structure and the high dipping volumes of these line screens an adaption and optimization of the machinery and the whole process was necessary to achieve high quality electrodes. Finally, it is shown that it is possible to manufacture continuiously in an industrial close roll-to-roll process platinum loaded electrodes, working successful as cathode in a Membran-Electrode-Assembly
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Bonifacio, Rafael Nogueira. „Desenvolvimento de processo de produção de conjuntos eletrodo-membrana-eletrodo para células a combustível baseadas no uso de membrana polimérica condutora de prótons (PEMFC) por impressão a tela“. Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-29082011-151940/.
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Energia é um recurso que historicamente apresenta tendência de crescimento de demanda. Projeções indicam que, para suprir as necessidades energéticas do futuro, será necessário um uso massivo do hidrogênio como combustível. O uso de sistemas de célula a combustível baseada no uso de membrana polimérica condutora de prótons (PEMFC) tem características que permitem sua aplicação para geração de energia elétrica em aplicações estacionárias, automotivas e portáteis. O uso de hidrogênio como combustível para PEMFC apresenta a vantagem de resultar em baixa emissão de poluentes quando comparado às dos combustíveis fósseis. Para que ocorram as reações em uma PEMFC é necessária a construção de conjuntos eletrodo-membrana-eletrodo (MEA), sendo o processo de produção de MEAs e os materiais utilizados, relevantes no custo final do kW instalado para geração de energia por sistemas de célula a combustível, o que é, atualmente, uma barreira tecnológica e financeira para a aplicação em grande escala desta tecnologia. Nesse trabalho foi desenvolvido um processo de produção de MEAs por impressão a tela que apresenta alta reprodutibilidade, rapidez e baixo custo. Foram desenvolvidos o processo de impressão a tela e a composição de uma tinta precursora da camada catalisadora (TPCC), que permitem o preparo de eletrodos para confecção de MEAs com a aplicação da massa exata de eletrocatalisador adequada para cátodos 0,6 miligramas de platina por centímetro quadrados (mgPt.cm-2) e ânodos 0,4 mgPt.cm-2 em apenas uma aplicação por eletrodo. A TPCC foi desenvolvida, produzida, aplicada e caracterizada, apresentando características semelhantes a de tintas de impressão a tela para outras aplicações. Os MEAs produzidos apresentaram desempenho de até 712 mA.cm-2 a 600 mV para MEAs de 25 cm2 e o custo para produção de MEAs de 247,86 cm2 capazes de gerar 1 kW de energia foi estimado em R$ 13.939,45, considerando custo de equipamentos, materiais e mão de obra.Energy is a resource that presents historical trend of growth in demand. Projections indicate that future energy needs will require a massive use of hydrogen as fuel. The use of systems based on the use of proton exchange membrane fuel cell (PEMFC) has features that allow its application for stationary applications, automotive and portable power generation. The use of hydrogen as fuel for PEMFC has the advantage low pollutants emission, when compared to fossil fuels. For the reactions in a PEMFC is necessary to build membrane electrode assembly (MEA). And the production of MEAs and its materials are relevant to the final cost of kW of power generated by systems of fuel cell. This represent currently a technological and financial barriers to large-scale application of this technology. In this work a process of MEAs fabrication were developed that showed high reproducibility, rapidity and low cost by sieve printing. The process of sieve printing and the ink composition as a precursor to the catalyst layer were developed, which allow the preparation of electrodes for MEAs fabrication with the implementation of the exact catalyst loading, 0.6 milligrams of platinum per square centimeters (mgPt.cm-2) suitable for cathodes and 0.4 mgPt.cm-2 for anode in only one application step per electrode. The ink was developed, produced, characterized and used with similar characteristics to ink of sieve printing build for other applications. The MEAs produced had a performance of up to 712 mA.cm-2 by 600 mV to 25 cm2 MEA area. The MEA cost production for MEAs of 247.86 cm2, that can generate 1 kilowatt of energy was estimated to US$ 7,744.14 including cost of equipment, materials and labor.
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Rajtrová, Gabriela. „Změna organizace výrobních linek“. Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2009. http://www.nusl.cz/ntk/nusl-222298.
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The main goal of this diploma thesis is new lay – out of organizational structure of assembly lines, which is leading to the material flow shortening and elimination of problems with factionalism of industrial process. In this thesis is introduce the company, where is proposed new organizational structure of assembly lines, together with description of deficiencies current organization. The good know ledges of assembly process and technology is important for the right modification. According theoretic findings it was proposed new organizational structure of assembly lines and the cost saving was calculated
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Huang, Shih-Yu, und 黃士羽. „Investigation of cell assembly process for electrowetting display“. Thesis, 2013. http://ndltd.ncl.edu.tw/handle/3f9zz3.
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碩士國立中興大學
精密工程學系所
101
Electrowetting display is considered as the most developed and innovative displays, however, there are some restrictions on production. For this paper we have succeeded in solving the problem of electro-wetting display assembly by TFT-LCD ODF (one drop fill) assembly process, it will be compatible to the TFT-LCD production line for mass production and lower costs. In addition, we designed the structure of electrowetting light valve with some advantages, such as high contrast, high brightness and lower response time possibly for e-reader. Furthermore, we also demonstrate that the thickness of 2 drops ink correspond to 4um with a lower driving voltage 10V.
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Li, Kuan-Ying, und 李冠穎. „Using PCB digital assembly process to preparation and characterization for Direct Methanol Fuel Cell“. Thesis, 2013. http://ndltd.ncl.edu.tw/handle/qx8b56.
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碩士國立臺北科技大學
製造科技研究所
101
This study aims to deal with the preparation of membrane-electrolyte assembly (MEA) of Pt/Ru/CB nanocomposite as well as connecting to a direct methanol fuel cell and using PCB process packaging to test the efficiency of the DMFC. The components assembled in DMFC are including anode flow field plates, MEA and current collector.Using PCB boards for the anode flow field plates as well as the electicity collector plates and the type of flow field plate adopts serpentine flow field. Pt/Ru/CB MEA developed in this study uses carbon paper as main body, assembling Pt/Ru/CB MEA in two sides respectively and combining with gas diffusion layer (GDL) in the most lateral and assembling with the hot-pressing units. For the efficiency of DMFC, liquid motors are used to press methanol mixed solution at specific temperature into DMFC. Besides, the cathode of DMFC adopts natural-breath method with air and uses DC electronic load to activate DMFC to investigate operating voltage (OCV) and further to set constant voltage to measure current to calculate the efficiency of DMFC. In addition, Transmission electron microscope TEM is employed to measure the structure of Pt/Ru/CB MEA. Initial results of I-V curve show that self-developed MEA of Pt/Ru/C nanocomposite can enhance around 0.2% current density of DMFC after being assembled like commercial MEA.
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Lee, Chen-Sheng, und 李俊昇. „The Design of Dispatching Rule for the Batch Process in a TFT-LCD Cell Assembly Factory“. Thesis, 2003. http://ndltd.ncl.edu.tw/handle/03045991701344806285.
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碩士國立交通大學
工業工程與管理系
91
The three main process of TFT-LCD are Array, Cell, and Module. The back-end of Cell process is combined by several batch workstations. Most scholars focus on how to improve the single batch workstation performance; however, the stability of the entire production system is ignored. Moreover, there are many process constraints at the batch workstation of Cell process, such as: queue time limitation, the special terms to run machine, etc. All of these will embitter the difficulty of scheduling. This study develops a dispatching rule that consider the production stability for the process contain multiple types of batch machine to accomplish the following two objects：shorten the production cycle time under the hypothesis of reaching the throughput target; increase the throughput under the hypothesis of satisifying due day constraint. This study develops a Synchronized Batching Heuristic rule (SBH) by using the concept of TOC. This rule is composed of two parts. At first part, it calculates the loading of each workstation and defines the bottleneck as the workstation with the minimum number of setup allowable. Then it sets the decision parameters based on the bottleneck location and schedule. At the beginning of second part, it evaluates the necessity of setup by comparing the loading time under setup situation to not setup situation. Second, it dynamic evaluates if load with the current batch size will cause the capacity of workstation being wasted too much. Finally, it determines the proper loading batch size and timing with consideration of the next job arrival time and the queue length of next batch workstation information. Simulation experiments reveal that by using the proposed dispatching rule can shorten the product cycle time under different system loading level. For the production system with high loading level, it can increase the throughput. Furthermore, it has the good performance if the uncertainty of arrival time is severe. Overall, the SBH rule has its effects for TFT-LCD Assembly Factory.
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Chen, Sung-Hsiang, und 陳頌翔. „Building the Scheduling Mechanism for Contiguous Batching Operations – A Case Study of TFT-LCD Cell Assembly Process“. Thesis, 2006. http://ndltd.ncl.edu.tw/handle/27958486677767453354.
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碩士國立交通大學
工業工程與管理系所
94
The three main manufacturing process of Thin Film Transistor – Liquid Crystal Display (TFT-LCD) are TFT Array process, Cell Assembly process and Module Assembly process. The Cell Assembly process includes several batch workstations; and the panel cannot wait too long without being processed after leaving the previous batch workstation. Previous researches and papers only consider the scheduling problems for single-stage with multiple-machines or for two-stages each with single-machine. Seldom scholars take into account the multiple-stage multiple-machine scheduling problem that exists in the cell assembly process. In view of this complex problem, we build the scheduling mechanism for contiguous batching operations by developing a mixed integer programming model and a heuristic rule which considers the waiting time constraint between workstations and the setup time minimization of bottleneck workstation. The proposed scheduling mechanism contains three modules: demand planning module, mixed integer programming (MIP) module, and heuristic rule module. First of all, the demand planning module approximates the arriving time of jobs to the first batch workstation. We set a new planning time unit to reduce the problem solving time. Secondly, we calculate the maximum available capacity during each planning period in the capacity evaluation module. In this module, the maximum available setup times is calculated for each workstation in order to recognize the bottleneck batch workstation. Then the mixed integer programming (MIP) module and the heuristic rule are built to set the detail schedule for contiguous batching operations considering the maximum lot sizing of each batch workstation and the waiting time constraint between two consecutive operations. The objective of this MIP model is to satisfy the throughput target and to minimize the total setup times of bottleneck workstation. For the sake of solving the real world cases rapidly, the heuristic rule is developed based on the concept of Theory of Constraint. The heuristic rule adopts full batch size policy to set the bottleneck workstation’s schedule so as to minimize the total setup time. Experimental result shows that the complexity of the scheduling problem is reduced by the new time unit, thus the time for solution deriving is shorten. Also, the MIP model can derive an optimal solution satisfying the waiting time constraint between workstations and the total setup time minimization. Finally, the heuristic rule can search out a feasible solution only in several seconds, and it enlarges the application range in this way. However, it may derive a schedule with more total setup times than the solution of MIP model.
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Di-Chiao, Yang, und 楊迪喬. „The Design of Master Production Scheduling for TFT-LCD Cell Assembly Factory with Two Kinds of Process Plans“. Thesis, 2008. http://ndltd.ncl.edu.tw/handle/2dhd42.
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碩士國立交通大學
工業工程與管理系所
96
TFT-LCD cell assembly factory takes charge of assembling the glasses from array factory with the color filters, and filling up with liquid. Traditionally, the factory adopts hot press(HPS) process for filling liquid, however, a new process, named one drop fill(ODF) process, is developed currently to accelerate the speed of filling. Concerning the surplus value of HPS process and the better efficiency of ODF process, here come some factories in which two kinds of processes work in coordination. In this thesis, a master production scheduling system is designed for the factory with two kinds of processes. The assembly factory processes glasses and color filters separately and assembles the two materials into products. In order to maximize the profit, the factory will not only accept the make-to-order (MTO) products but also produce the make-to-stock (MTS) products to use up capacity. Each product has three kinds of attributes including size, liquid type and process, and every workstation takes account of different attribute to decide whether setup or not. This is complex for planning setup schedule. Besides, the batch machines used in HPS process operate only when the accumulated units of the same job type reach the predetermined level. The proposed master production scheduling system first estimates setup times which caused by the make-to-order products roughly so as to calculates capacity loading of each workstation, then defines the highest and the second high loading workstation as main bottleneck and secondary bottleneck. Considering the loading of secondary bottleneck and the attributes of products and regarding profit maximization as the target, the bottleneck scheduling model is designed to decide the product type, quantity and the production sequence on each machine of the bottleneck workstation. Then the batch scheduling model is developed to decide the product quantity and production sequence on each machine of the batch stations in order to match with the results of bottleneck scheduling. Also, a feedback mechanism is developed to ensure that no conflict exists between the scheduling of bottleneck and that of batch workstations. Several scenarios with practical data are used to verify the practicability of the master production scheduling system, and simulation is applied to confirm that the results of this scheduling system are achievable. The simulation results showed that the scheduling system in this thesis is quite functional and definitely practicable.
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Wu, Yen‐Feng, und 吳彥夆. „The Construction of Master Production Scheduling System and Available-to-Promise Mechanism under Process Selectable Environment for the TFT-LCD Cell Assembly Factory“. Thesis, 2010. http://ndltd.ncl.edu.tw/handle/99289380457446392097.
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碩士國立交通大學
工業工程與管理學系
98
The cell assembly factory assembles the color filter with the glass substrate produced from array factory, and filling with liquid crystal for making thin film transistor liquid crystal display (TFT-LCD). In the process selectable environment, each custom order can specify its required process such that orders can be classified as hot press (HPS) specified, one drop fill (ODF) specified, and unspecified. Factories that producing middle and small size products, thus take make-to-order (MTO) mixed with make-to-forecast (MTF) policy and try to keep some unused capacity to response the new arrived customer orders. As a result, this thesis proposes a master production scheduling system to plan a schedule with the most unused capacity, and develops the available-to-promise mechanism to response the new arrived customer orders in short time. The proposed master production scheduling system solves the schedule for all major workstations. At first, rough cut capacity planning mechanism is used to identify three major workstations and then distinguishes the bottleneck and sub-bottleneck among them. Then major workstation planning mechanism is used to determine the production quantity of HPS process and of ODF process. An integer programming model is built to solve the schedule for the three major workstations simultaneously with minimization of the bottleneck’s setup time as the objective function. The proposed available-to-promise mechanism is applied when the new orders arrives. It adopts the order promise module to check whether the quantity available to promise and the capacity to promise can fulfill the new arrived orders or not. If the new order can not be fulfilled, rescheduling module freezes the schedule of the firm orders and reschedule the make to forecast orders and new arrived orders, with consideration of minimizing the difference of the bottleneck’s average utilization rate before and after rescheduling. According to the result of cases analysis, the proposed master production scheduling system can solve the schedule of the three major workstations and minimize setup times for the bottleneck with efficiency. The proposed available-to-promise mechanism can make the new arrived orders fulfilled with the time faster than rerunning the proposed master production scheduling system. Key words：TFT-LCD, major workstations, production quantity, inter-period setup, actual order
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Umerska, A., Krzysztof J. Paluch, M. J. Santos-Martinez, C. Medina, O. I. Corrigan und L. Tajber. „Chondroitin-based nanoplexes as peptide delivery systems-Investigations into the self-assembly process, solid-state and extended release characteristics“. Thesis, 2015. http://hdl.handle.net/10454/9416.
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YesA new type of self-assembled polyelectrolyte complex nanocarrier composed of chondroitin (CHON) and protamine (PROT) was designed and the ability of the carriers to bind salmon calcitonin (sCT) was examined. The response of sCT-loaded CHON/PROT NPs to a change in the properties of the liquid medium, e.g. its pH, composition or ionic strength was studied and in vitro peptide release was assessed. The biocompatibility of the NPs was evaluated in Caco-2 cells. CHON/PROT NPs were successfully obtained with properties that were dependent on the concentration of the polyelectrolytes and their mixing ratio. X-ray diffraction determined the amorphous nature of the negatively charged NPs, while those with the positive surface potential were semi-crystalline. sCT was efficiently associated with the nanocarriers (98-100%) and a notably high drug loading (13-38%) was achieved. The particles had negative zeta potential values and were homogenously dispersed with sizes between 60 and 250 nm. CHON/PROT NPs released less than 10% of the total loaded peptide in the first hour of the in vitro release studies. The enthalpy of the decomposition exotherm correlated with the amount of sCT remaining in NPs after the release experiments. The composition of medium and its ionic strength was found to have a considerable influence on the release of sCT from CHON/PROT NPs. Complexation to CHON markedly reduced the toxic effects exerted by PROT and the NPs were compatible and well tolerated by Caco-2 cells.
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Khan, Omar. „Characterization and Modeling of the Remodeling Process that Occurs in Modular Tissue Engineered Constructs Assembled Within Microfluidic Perfusion Chambers“. Thesis, 2011. http://hdl.handle.net/1807/29772.
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Using a modular approach, a vascularized tissue construct is created by embedding functional cells within submillimeter-sized collagen cylinders (modules) while the outside surfaces are seeded with endothelial cells (EC). The void spaces created by randomly packing modules into a container form EC-lined perfusion channels. Upon implantation, the tissues are remodeled by and integrated into the host and experience, to some degree, immune and inflammatory responses. This work utilized microfluidic techniques to study and model the tissue remodeling in vitro in the absence of the host response. When the construct’s tortuous perfusion channels were reproduced in poly(dimethylsiloxane) microfluidic devices and lined with EC, perfusion at higher flow rates reduced EC activation and maintained the desired quiescent EC phenotype. When applying these results to collagen constructs, higher flow rates were not achievable due to the weak mechanical properties of collagen. To increase the collagen’s mechanical strength, a semi-synthetic collagen/poloxamine-methacrylate hydrogel was examined but due to its heterogeneous surface composition, there was inadequate EC attachment and the material was deemed unsuitable for this application. Proceeding with lower flow rates, tissues assembled within microfluidic perfusion chambers from EC-seeded collagen modules showed that over the course of 24 hours, perfusion did not significantly increase activation but instead increased KLF2 expression, a transcription factor involved in the establishment of EC quiescence, and disrupted VE-cadherin bonds between adjacent EC. However, after 1 week of perfusion, the majority of EC were lost. To ameliorate this loss, mesenchymal stromal cells (MSC) were embedded within the modules in order to take advantage of their anti-apoptotic and immunomodulation effects. The MSC temporarily mitigated the loss of the EC but did not prevent it. They did, however, take on a phenotype similar to smooth muscle cells and migrated towards the EC. Perhaps this indicates that the combination of EC, MSC and perfusion drives the creation and assembly of pseudo vessels. Together, the microfluidic techniques used in this study to assemble and perfuse modular tissues revealed new insights into the remodeling process and exposed critical issues surrounding the adaptation of the EC to the combination of perfusion, remodeling and changing flow fields.
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Siegel, Frank. „Tiefdruckverfahren zur Herstellung von Katalysatorschichten für (PEM) Brennstoffzellen“. Doctoral thesis, 2014. https://monarch.qucosa.de/id/qucosa%3A20464.
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Diese Dissertation befasst sich mit der industrienahen Herstellung von Katalysatorschichten für Polymer-Elektrolyt-Membran-Brennstoffzellen mit Hilfe des Tiefdrucks als Fertigungsverfahren. Um die Anforderungen an die Katalysatorschicht hinsichtlich der Schichtdicke zu erreichen, wird ein Linienraster für den Tiefdruck entwickelt. Das patentierte und verifizierte Designkonzept des Linienrasters ermöglicht es, trotz Tinten mit geringem Feststoffgehalt hohe Trockenschichtdicken zu erzeugen. Aufgrund des verwendeten Tiefdruckrasters sind Optimierungsschritte an der Fertigungsanlage notwendig, um eine hohe Schichtqualität zu erreichen. Schließlich werden kontinuierlich und industrienah Katalysatorschichten gefertigt, die als Membran-Elektroden-Einheit in einer Polymer-Elektrolyt-Membran-Brennstoffzelle erfolgreich eingesetzt werden.This work presents an industrial close manufacturing process of active electrodes for Polymer Electrolyte Fuel Cells utilizing an adapted gravure printing process. To meet the requirements of the electrodes regarding the layer thickness (weight) and quality a novel line screen with maximized dipping volume for gravure printing was developed and investigated. A design rule for this kind of screens was realized and verified by a successful manufacturing of electrodes with different dried layer thicknesses. Due to the rough structure and the high dipping volumes of these line screens an adaption and optimization of the machinery and the whole process was necessary to achieve high quality electrodes. Finally, it is shown that it is possible to manufacture continuiously in an industrial close roll-to-roll process platinum loaded electrodes, working successful as cathode in a Membran-Electrode-Assembly.