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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
451

Optimal Production and Delivery Scheduling Models for a Supply Chain System of Deteriorating Items

Wu, Bingqing 10 July 2012 (has links)
The market is varying from minute to minute nowadays. Increase cooperation and pursue the optimal interest of the integrated supply chain become a more effective way than act alone in the competition. In this research, an integrated inventory policy between singleproducer and multi-buyer is developed and two inventory models are built. The first model extends the research of Lin and Lin (2007) by changing the single-buyer system to the multibuyers one. Both backorder of buyers and deteriorating items of each party (producers level, buyers level, and during transport) are considered herein. The second model is based on the research of Woo et al.(2001) and Model 1 by takes raw material cost and remanufacturing proceeds into account additional. In both model, the producer and buyers collaboratively work at minimizing their total operation cost and the problems are solved under an assumption of equal replenishments and production cycles. The algorithms to find the optimal solutions are given, and numerical examples are presented. Sensitivity for systems parameters is also analyzed and all calculations are completed by software Matlab and Maple.
452

An Intelligent Computational Approach to the Optimization of Inventory Policies for Single Company

Duan, Qinglin 27 September 2012 (has links)
This study develops and tests a computational approach for determining optimal inventory policies for single company. The computational approach generally comprises of two major components: a meta-heuristic optimizer and an event-driven inventory evaluation module. Meta-heuristic is a powerful search technique, under the intelligent computational paradigm. The approach is capable of determining optimal inventory policy under various demand patterns regardless their distribution for a variety of inventory items. Two prototypes of perishability are considered: (1) sudden deaths due to disasters and (2) outdating due to expirations. Since every theoretical model is specially designed for a certain type of inventory problem while the real world inventory problems are numerous, it is desirable for the newly proposed computational approach to cover as many inventory problems/models as possible. In a way, the proposed meta-heuristic based approach unifies many theoretical models into one and beyond. Experimental results showed that the proposed approach provides comparable results to the theoretical model when demand follows their assumption. For demands not well conformed to the assumption, the proposed approaches are able to handle it but the theoretical approaches do not. This makes the proposed computational approach advantageous in that it can handle various types of real world demand data without the need to derive new models. The main motivation for this work is to bridge the gap between theory and practice so as to deliver a user-friendly and flexible computational approach for rationalizing the inventory control system for single company.
453

Microencapsulation Techniques of Self-Healing Concrete Properties

Gilford III, James 12 July 2012 (has links)
ABSTRACT Recent studies in the literature have demonstrated the ability of self-healing processes to be effective in enhancing the overall life of concrete. The main goal of this project is to evaluate and to control specific parameters for the production of an effective self-healing matrix that can be utilized within the application of self-healing concrete. Therefore, the project objective is to synthesize microcapsules using dicyclopentadine and sodium silicate and to evaluate the effects of pH, temperature, and agitation rate on microcapsule morphology. The microcapsule diameter, yield analysis, and shell thickness were characterized using scanning electron microscopy. During the experimental analysis, it was determined that temperature possesses a direct relationship with the pH for both sodium silicate and DCDP. As the temperature increased during the trials, the pH decreased. Temperature had a direct impact on the forming of the wall and core during the interfacial polymerization phase. Although the ability to maintain this consistency with the pH is important and essential, agitation rate is the key factor that controls the microcapsule capsule diameter size. As the agitation rate is increased, the microcapsule diameter size will decrease. If the agitation rate decreases, the microcapsules will become larger. Sodium silicate, however, was not consistent with the normal parameter matrix, due to its alkaline nature. As the agitation rate increased, the size remained normal and consistent. This was due to the attempt to stabilize the sodium silicate solution for the micro-encapsulation procedure of Urea-Formaldehyde. Nevertheless, both sodium silicate and DCDP trials were successful in meeting the overall objective of this thesis, which was to control the performance parameters of the two self-healing methods.
454

EVALUATION OF METHODS TO OPERATE GATE VALVES USING ELAPSED TIME, RATING OF PERCEIVED EXERTION, AND ELECTROMYOGRAPHY

Hutchinson, Francis Williams 02 August 2012 (has links)
Hutchinson, Francis Williams, B.G.S., Louisiana State University, 1989 Master of Science in Industrial Engineering, Summer Commencement, 2012 Major: Industrial Engineering Evaluation Of Methods To Operate Gate Valves Using Elapsed Time, Rating Of Perceived Exertion, And Electromyography Thesis directed by Professor Fereydoun Aghazadeh, Ph.D., PE Pages in thesis, 86. Words in abstract, 253. ABSTRACT Industrial valve handwheels are in common use in many industries to block, allow, or regulate the flow of materials within a system. Significant numbers of musculoskeletal disorders have been attributed to turning valve handwheels. The torques encountered to break and/or turn these handwheels often exceeds 100 Nm and therefore necessitate the use of special wrenches or other aids. The literature reveals that most of the research has been done to determine the operators capabilities for developing the breaking forces. After breaking, the continuous muscular effort for as much as five to fifteen minutes required to fully open or close some valves is believed to place greater demands physically and physiologically on the operator than the initial breaking torque requirement. This study used electromyographic data taken from two different locations, the elapsed time to fully open a valve, and Borgs subjective Ratings of Perceived Exertion (RPE) obtained from the participants to determine the optimum method for opening the valve. The data was obtained from a group of 10 participants who fully opened the valve by using their hands only, using a conventional valve wrench, and using a modified valve wrench. The tasks were repeated with the valve wheel set at two different torque requirements: 25Nm and 50Nm. The data gathered was then analyzed and evaluated to determine if the modified wrench was the optimum method to open the valve. Although the modified wrench was demonstrated to be the most efficient under some conditions, advantages from further testing and modifications to the wrench were indicated.
455

The Impact of 5S on the Safety Climate of Manufacturing Workers

Srinivasan, Siddarth 21 November 2012 (has links)
The occupational injury rate in the manufacturing sector is higher than the average of all private industries, necessitating safety studies. Occupational safety can be measured through different approaches. Safety climate, a predictive measure of safety, studies the workers perceptions of safety of the workplace. This measure includes several dimensions of safety like management commitment, involvement and work place hazard evaluation and was chosen as a method of evaluation in this study. Even though occupational safety is an important concern, management often prioritizes reducing waste and cost. So, there is a necessity for some technique which reduces waste and simultaneously improves safety. Lean has been effective in reducing waste and costs. Researchers have shown that lean might improve occupational safety too. Nevertheless, empirical evidence to prove the relationship between the two is insufficient. In this study, 5S, a lean technique, was implemented in a manufacturing company and its impact on safety climate of the workers was studied to show the relationship between lean and safety climate of the workers. Case and control groups took the Safety Climate Assessment Toolkit, a safety climate questionnaire, both before and after the 5S event. The effectiveness of the 5S event was determined through three productivity measures (cycle time, floor space utilized, ratio between inventory and units produced). Statistical analysis showed that the safety climate of the manufacturing workers increased after the 5S event (p value = 0.0085). The 5S event was also shown to be effective. The cycle time was reduced by 16.6% and floor space utilization decreased by 22.2%. 5S not only improved the processes by reducing waste and costs, but also improved the safety climate of workers.
456

Analysis of a Construction Small-Projects Rework Reduction Program for a Capital Facility

Zhang, Di January 2009 (has links)
Reducing field rework is widely regarded as an effective way of improving construction performance in terms of productivity, cost, schedule, quality, and safety. While existing rework reduction programs and much literature exist concerning this challenge, there is a need for further analysis and continuous improvement of rework reduction methods. Based on such an analysis, this research develops a generalized conceptual model for a rework reduction program, which is intended to reduce rework by managing a continuous improvement loop with four functional processes: (1) rework tracking and cause classification, (2) evaluation of rework and its causes, (3) corrective action planning, and (4) integration of changes into the total management system. A case study is conducted to examine and verify the functional mechanisms and effectiveness of the generalized model, by investigating a rework reduction program implemented in practice that represents the generalized model, and by analyzing the impact trends on rework in terms of frequency, cost, and labor hours over a considerable time period. The results indicate that rework can be reduced significantly with such a program.
457

The Making of a Sufi Order Between Heresy and Legitimacy: Bayrami-Malāmis in the Ottoman Empire

Yavuz, Fatma 16 September 2013 (has links)
Revolutionary currents with transformative ideals were part of the Sufi religious identity during the late medieval Islamic period. This dissertation tries to make sense of this phenomenon by focusing on the historical evolution of the Bayrami-Malāmi Sufi order within the Ottoman Empire. The scope of the study extends from the beginnings of the order during the ninth/ fifteenth century until its partial demise by the end of the eleventh/seventeenth century. The Bayrami-Malāmiyya was essentially marked by a reaction towards the established Sufi rituals of the time: its adherents refused to wear Sufi clothes, take part in gatherings of remembrance of God, or rely upon imperial endowments for their livelihood. I suggest in this study that Bayrami-Malāmis carried some of the distinguishing signs of religiosity belonging to the anarchic period between the Mongol attacks and the rise of the powerful Islamic Empires. During that time, many local forms of Sufism, which were tied to charismatic and independent communities that were quite prevalent and powerful in their own domains, had emerged. These communities often held a particular vision regarding the saint, whose persona came to be defined in terms exceeding that of a spiritual master, often taking the form of a community elder or a universal savior. Taking their inspiration from this period, Bayrami-Malāmis reconstructed their teachings and affiliations as the social and political conditions shifted in Anatolia. While several pīrs were executed for being heretics and making messianic claims in the sixteenth century, the Order was able to put together a more prudent vision based on the writings of Ibn Arabi (d. 638/1240) during the seventeenth century. After this, it became a secretive order that attracted the upper classes in the imperial city of Istanbul, and extended its influence to imminent poets, bureaucrats, and political figures. This study is essentially concerned with the dynamics of this evolution. It also tries to conceptualize how the teachings of the Order were rooted in the persona of the saint, who was regarded in divine terms and seen as the culmination point of creation. This worldview had the potential to lead to apocalyptic urges that did not harbor the immediate end of the world, but yearned for the beginning of a new era in which people would understand and experience divinity in its true monistic fashion.
458

Utveckling av gåbord

Eklind, Samuel January 2007 (has links)
No description available.
459

Konstruktion av en båtlift

Kostkevicius, Erik, Nikuolasson, Alfred January 2007 (has links)
Examensarbetet har utförts i samarbete med Produktutvecklarna AB i Växjö. Arbetet har varit att konstruera en båtlyft för fritidsbåtar, med en vikt på maximalt 1000 kg. Lyften skall kunna lyfta båten ifrån en båttrailer, och den skall kunna användas som vinterförvaring, Den skall också kunna lutas 30 grader för att underlätta tvättning och underredsbehandlig. Arbetet innefattar konstruktion, hållfasthetsberäkningar, materialval, simuleringar samt dimensioneringar av lager och hydraulkolvar.
460

Smörjning Av Lager / Lubrication Of Bearing

Ahlman, Per-Arne January 2009 (has links)
The work thesis was performed at Assalub a company which is situated in Åtvidaberg. The company works with developing, manufacturing and marketing equipment for handling of lubricants for light and heavier industry. The work thesis it is based on a inquiry Assalub got from MacGregor which is a company within cargo solution, from port to offshore system. For unloading grain and other material from the ship cargo it is used combined inlet feeder and screw conveyor, there the inlet feeder is drilling down through the cargo and feed the screw conveyer with material to further destination. At the bottom of the screw conveyer and the inlet feeder there is a bearing that keep the parts together. However the lubrication of the bearing must be made manually. Until now the bearing was lubricated manually through a grease nipple from the bottom of the drill once a day.   The purpose of the thesis was the construction of a lubricating system namely a pump with a grease container which should be placed inside the space of the screw conveyer, so the bearing will be continually lubricated and able to work several days without any stoppage. After receiving drawings and operating data for the screw conveyer, the details for the construction was designed in CAD system Solid Edge. The solid mechanics calculations on the weakest point on the construction was made by hand and afterwards the drawings for respectively details was made. The construction was completed, but because of the time limit for this work thesis, the manufacturing, mounting and testing were not included in these weeks. The grease containers capacity is approximately seventy-two hours, although desirable should be up to seven days. According to the solid mechanics calculations, the construction should have no problem to resist the stresses it would be exposed to. Since this is a prototype there is probably some adjustments and improvements to do, but the estimating is that the system should work properly as it is now.

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