• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 29
  • 18
  • 5
  • 4
  • 2
  • 1
  • 1
  • Tagged with
  • 67
  • 67
  • 19
  • 17
  • 16
  • 15
  • 13
  • 12
  • 11
  • 10
  • 10
  • 8
  • 7
  • 7
  • 6
  • 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.
31

Knowledge based system implementation for lean process in low volume automotive manufacturing (LVAM) with reference to process manufacturing

Mohamed, N.M.Z.Nik, Khan, M. Khurshid 04 August 2011 (has links)
Yes / Global manufacturing industry mostly depends on new product development and processes to become competitive. The product development process for automotive industry is normally complicated, lengthy, expensive, and risky. Hence, a study of lean manufacturing processes for low volume manufacturing in automotive industry is proposed to overcome this issue by eliminating all wastes in the lengthy process. This paper presents a conceptual design approach to the development of a hybrid Knowledge Based (KB) system for lean process in Low Volume Automotive Manufacturing (LVAM). The research concentrates on the low volume processes by using a hybrid KB system, which is a blend of KB system and Gauging Absences of Pre-requisites (GAP). The hybrid KB/GAP system identifies all potential waste elements of low volume process manufacturing. The KB system analyses the difference between the existing and the benchmark standards for lean process for an effective implementation through the GAP analysis technique. The proposed model explores three major lean process components, namely Employee Involvement, Waste Elimination, and Kaizen (continuous improvement). These three components provide valuable information in order for decision makers to design and implement an optimised low volume manufacturing process, but which can be applied in all process manufacturing, including chemical processing.
32

Low Volume Resistance Exercise Prevents Loss of Muscle Mass and Function During 14 Days of Knee Immobilization

Oates, Bryan R. 07 1900 (has links)
<p> We aimed to determine the effectiveness of a low volume of high-intensity resistance exercise, alone (EX) or in combination with a whey protein supplement (WHY +EX), on prevention of muscle mass and strength loss following 14 days of knee immobilization in humans. Seventeen recreationally active (i.e., exercise ≤ 2-3 d·wk^-1) participants (23.9±5.0 yr; BMI = 25.4±3.6 kg·m^-2) were divided into three groups: exercise (EX; n=6), whey protein supplementation with exercise (WHY+EX; n=6), and control (CON; n=5). All subjects wore a knee-immobilization brace such that one leg was completely non-weight bearing for 14d. The resistance exercise (RE) were performed unilaterally and consisted of one set of ten repetitions of leg press (with plantar flexion at full extension), knee extension, and seated calf raises every other day during the 14d immobilization period, at 80% of one repetition maximum. Subjects in the WHY+EX group consumed two 30g boluses of whey protein daily while EX and CON consumed isocaloric carbohydrate beverages. Immobilization induced a significant reduction (p<0.05) in thigh cross-sectional area (CSA), isometric knee extensor strength, and isometric plantar flexion strength in CON but not in EX and WHY+EX. There were significant losses in lower leg CSA for all three groups, with a tendency for losses to be mitigated in both the EX and WHY+EX groups versus CON (p=0.065). The two constituent muscles of the triceps surae muscle group showed a differential response to the RE training with the gastrocnemius showing reductions in CSA almost uniformly across the three groups whereas soleus CSA was significantly reduced in the CON (p<0.05) but not in the EX and WHY+EX groups. We conclude that a relatively low volume of high-intensity resistance exercise is an effective countermeasure against atrophy of the thigh and the soleus muscle, as well as against knee extension and plantar flexion strength loss during 14d of leg immobilization. As a countermeasure to immobilization, there is no additional benefit of consumption of a daily whey protein supplement in combination with resistance exercise in maintaining muscle mass or strength.</p> / Thesis / Master of Science (MSc)
33

Field performance of geogrid reinforced low-volume pavements

Joshi, Rutuparna Vidyadhar 05 November 2010 (has links)
For the past three decades, geosynthetics have been recognized as materials that can significantly improve the performance of pavements on weak subgrade. Pavements exhibit non-linear elasto-plastic behavior. The addition of geosynthetics is undoubtedly beneficial. This being said, researchers have concentrated more on lower life cycle cost and high benefit-cost ratio whereas much less attention has been given to the complex behavior of the reinforced pavement system. Comprehension of the short-term and long-term field performance of reinforced pavements under continued traffic and cyclic environmental loading has remained unexplored. There is empirical evidence indicating quantitative benefits of reinforced versus unreinforced pavement structure. However, quantification of the relative benefits of different types of reinforcement like geogrids and geotextiles lacks information. Further, evaluation of the benefits and comparison of chemical stabilization in the form of lime treatment with mechanical stabilization in the form of reinforcement for pavements on soft soils has received lack of attention. In view of this, full-scale instrumented reinforced and lime treated pavement sections with different schemes were studied. Regular Falling Weight Deflectometer (FWD) testing was conducted in a Farm-to-Market Road, in Grimes County, Texas. Three different geosynthetic products were used for base reinforcement and lime treatment was used for subbase stabilization. Deflection measurements for 9 field trips in 3.5 years were evaluated. Modified deflection basin parameters (DBPs) were defined to typically identify layer properties and were used to measure the relative damage to the base, subbase and subgrade for different sections. A modified Base Damage Index (BDI) and a modified Base Curvature Index (BCI) were defined as a part of this study to capture the benefit of reinforced base and lime stabilized subbase respectively. The variation in the DBPs over three periods of wetting and drying along with explanation of the observed trends forms a part of this research. In addition, a number of condition surveys were performed, during 3 years, to visually identify distresses in various sections. A unique distress quantification technique was developed for measuring deterioration of the pavement sections in terms of the observed distresses and FWD measurements. With this, an index of pavement performance was developed. Thus, the FWD deflection data analyses complemented by visual observation, reveals important information on performance of different geosynthetics with the same base course. Analysis of the field performance of the multiple experimental sections throws light on the relative merits of base reinforcement against lime stabilization. / text
34

Estudo laboratorial de agregado reciclado de resíduo sólido da construção civil para aplicação em pavimentação de baixo volume de tráfego. / Laboratory study of recycled aggregate from construction and demolition waste to be used as a pavement material in a low volume road.

Motta, Rosângela dos Santos 29 August 2005 (has links)
A crescente quantidade de resíduos sólidos da construção civil gerada em cidades de médio e grande portes tem sido fonte de preocupação em todo o mundo em função de questões ambientais, econômicas e até sociais. Desta forma, a reciclagem dos resíduos de construção para a produção de agregados torna-se uma alternativa interessante, principalmente em função de normas e pesquisas já existentes que podem garantir sua aplicação. A pavimentação com agregados reciclados já vem sendo amplamente realizada em alguns países onde, inclusive, já existe conhecimento consolidado sobre o assunto. No Brasil, as primeiras experiências que remetem ao uso de agregados reciclados em pavimentação datam de meados da década de 80. Desde então, poucas pesquisas sobre o tema vem sendo realizadas, embora haja a necessidade de se procurar novas técnicas e materiais no setor de infra-estrutura rodoviária, uma vez que o país possui somente cerca de 10% de suas vias, muitas vezes urbanas, em condição pavimentada. Este trabalho analisa laboratorialmente aspectos físicos e de comportamento mecânico do agregado reciclado da cidade de São Paulo, a ser utilizado em camadas de base, sub-base ou reforço do subleito de pavimento, em substituição aos materiais convencionais, com enfoque em vias urbanas de baixo volume de tráfego. O estudo envolveu a análise do agregado reciclado in natura, além de sua mistura com 4% de cal ou 4% de cimento Portland, como forma de promover um aumento da resistência do material. Além disso, foram realizados alguns ensaios com brita graduada (material comumente empregado em pavimentos), a fim de comparar resultados. Concluiu-se que o agregado reciclado analisado é de uso promissor em pavimentação, dadas suas propriedades físicas e mecânicas satisfatórias, comparáveis a tradicionais materiais estabilizados granulometricamente ou mesmo a brita graduada simples. Ademais, a adição de cal ou cimento Portland apresenta-se como excelente alternativa quanto ao requisito de aumento de resistência do material reciclado. / The increasing amount of construction and demolition waste generated in medium-sized and large cities has become a source of concern all over the world due to environmental, economic and even social issues. Thus, the recycling of construction and demolition waste to produce aggregates becomes an interesting alternative mainly because of existing specifications and researches that can guarantee its application. Paving with recycled aggregates has already been largely done in some countries where there is even a consolidated knowledge about the subject. In Brazil, preliminary experiences that refer to the use of recycled aggregates in pavement layers date from the mid 80s. Since then, few researches on the subject have been conducted, although it is necessary to look for new techniques and materials in the road infra-structure sector, since the country has only about 10% of its roads, many times urban ones, in paved condition. This work analyses recycled aggregates from São Paulo City as a material to be used in base, subbase or subgrade reinforcement courses in urban roads of low-volume traffic, to replace conventional materials. So, physical and mechanical behaviour aspects of the material were observed by means of laboratory tests. This study involved the analysis of recycled aggregate in natura, as well as its mix with 4% of lime or 4% of Portland cement, to promote a gain in strength. Moreover, some tests were made using graded crushed rock (that is commonly used as a pavement material) so as to compare the results. It was concluded that recycled aggregate is promising for paving, given its satisfactory physical and mechanical properties, comparable to traditional granulometrically stabilized materials or even to simple graded crushed rock. The addition of lime or Portland cement is an excellent alternative concerning the increase in strength of those recycled materials.
35

Development of a Rational Method of Designing Hot Mix Asphalt (HMA) for Low Volume Roads

Nanagiri, Yamini Varma 05 January 2005 (has links)
The Superpave mix design system is being adopted by most of the states in the Unites States. Since the Superpave system was developed on the basis of data mostly obtained from medium to high traffic volume roads, there is a need to develop criteria for mix design for Hot Mix Asphalt (HMA) mixes for low traffic volume roads. In this study funded by the six New England states, research was carried out to develop a proper mix design system for low volume roads from the standpoint of durability properties and then, once a good mix design system was available, check it to determine if it meets required strength properties. For low volume roads the performance is primarily affected by the environment and not by traffic, the approach in this study has been to determine the optimum value of a key volumetric property and an optimum number of design gyrations for producing compacted HMA mixes with adequate resistance against aging/high stiffness related durability problems. Six mixes were obtained in which only one can be characterized as a fine mix, and the remaining five were all relatively close to the maximum density line - three of them were with 9.5 mm Nominal Maximum Aggregate Size (NMAS), and the other two were with 12.5 mm NMAS. Based on the results from performance testing, film thickness of 11 microns in samples compacted to 7 percent voids was found to be desirable from considerations of stability and durability and a design VMA of 16 percent was determined to be optimum for producing durable and stable mixes for low volume roads. Results from testing of in-place mixes from good performing 10 to 12 year old low volume roads indicated a design gyration of 50 for obtaining a void content of 4 percent for mixes with gradations close to the maximum density line.
36

Capability to Promise (CTP) Handling Strategy in SAP

Laoniphon, Patriya, Yu, Wenyi January 2011 (has links)
Nowadays, many companies attempt to adapt their production planning and strategy to make order fulfillment more flexible. In manufacturing, the capacity and capability constraints are key factors which need efficient production planning for controlling service level and minimizing inventory cost. This thesis focuses on looking for the economic and efficient strategies for Capability to Promise or CTP handling. This strategy is proposed to work for Low Volume/High Mixed product manufacturing. Moreover, SAP is used as Enterprise Resource Planning (ERP) system for steering the CTP handling strategies in order to increase automated order handling regarding cost efficiency. The results of this research are both concepts and implementations on how to set CTP handling by using SAP, regarding the demand uncertainty environment in Make to Order (MTO) fulfillment.
37

Microwell devices for single-cell analyses

Lindström, Sara January 2009 (has links)
Powerful tools for detailed cellular studies are emerging, increasing the knowledge ofthe ultimate target of all drugs: the living cell. Today, cells are commonly analyzed inensembles, i.e. thousands of cells per sample, yielding results on the average responseof the cells. However, cellular heterogeneity implies the importance of studying howindividual cells respond, one by one, in order to learn more about drug targeting andcellular behavior. In vitro assays offering low volume sampling and rapid analysis in ahigh-throughput manner are of great interest in a wide range of single-cellapplications. This work presents a microwell device in silicon and glass, developed using standardmicrofabrication techniques. The chip was designed to allow flow-cytometric cellsorting, a controlled way of analyzing and sorting individual cells for dynamic cultureand clone formation, previously shown in larger multiwell plates only. Dependent onthe application, minor modifications to the original device were made resulting in agroup of microwell devices suitable for various applications. Leukemic cancer cellswere analyzed with regard to their clonogenic properties and a method forinvestigation of drug response of critical importance to predict long-term clinicaloutcome, is presented. Stem cells from human and mouse were maintainedpluripotent in a screening assay, also shown useful in studies on neural differentiation.For integrated liquid handling, a fluidic system was integrated onto the chip fordirected and controlled addition of reagents in various cell-based assays. The chip wasproduced in a slide format and used as an imaging tool for low-volume sampling withthe ability to run many samples in parallel, demonstrated in a protein-binding assay fora novel bispecific affinity protein. Moving from cells and proteins into geneticanalysis, a method for screening genes from clones in a rapid manner was shown bygene amplification and mutation analysis in individual wells. In summary, a microwelldevice with associated methods were developed and applied in a range of biologicalinvestigations, particularly interesting from a cell-heterogeneity perspective. / QC 20100728
38

Análise estrutural de pavimentos de baixo volume de tráfego revestidos com solo modificado com cal considerando ensaios laboratoriais e monitoramento de trechos experimentais / Structural Analyze of low-volume roads covered with soil modified with lime with considering of laboratorial tests and monitoring of experimental sections

Katz, Leonardo Behak January 2013 (has links)
Os solos das regiões arrozeiras apresentam características geotécnicas inadequadas para uso como revestimentos primários de estradas. Isto força o transporte de materiais de jazidas distantes, o que, além de onerar o custo de construção, nem sempre é uma solução durável. Nesta tese relata-se uma pesquisa que apresenta uma solução para esse problema: a pavimentação de estradas de baixo volume de tráfego com solo local modificado com cal. Foram realizados estudos laboratoriais e de campo, e os resultados analisados através de uma abordagem mecanístico-empírica. Dois pavimentos experimentais com revestimentos de solo-cal foram construídos e monitorados próximo a Cebollatí, leste do Uruguai. Foram realizados ensaios de caracterização e comportamento mecânico do solo e de misturas de solo e cal, variando-se o teor de cal, o tempo de cura e a energia de compactação. Realizaram-se ensaios de módulo de resiliência, para o qual foi projetado, montado e operado o primeiro equipamento de ensaios de carga repetida na compressão triaxial do Uruguai. Também foram realizados ensaios de fadiga na compressão diametral para o solo modificado com 3% e 5% de cal, curado por 28 e 150 dias. Para entender o comportamento das camadas de solo modificado com cal submetidas ao tráfego, realizou-se uma análise conjunta dos resultados laboratoriais e do monitoramento dos trechos experimentais, com uso de modelos computacionais. Apesar das limitações construtivas, de terem sido liberados ao tráfego em plena safra e das más condições de drenagem da região, após 5 anos de trafego, os pavimentos não mostram trincas de fadiga ou afundamentos nas trilhas de roda. Assim, a pavimentação de estradas de baixo volume de tráfego em regiões arrozeiras com revestimentos de solo local modificado com cal provou ser uma alternativa economicamente vantajosa, por reduzir custos de construção e manutenção, e sustentável, por preservar materiais não-renováveis, como solos e rochas. / Soils in rice plantation areas generally present geotechnical characteristics unsuitable for use as primary wearing course of roads. Because of that, it is necessary to import materials from distant sites, a solution that, besides increasing construction cost, is rarely long-lasting. In this thesis a research on paving low volume roads with lime modified local soils is reported, in order to present an alternative solution to that problem. Both laboratory and field studies were carried out and the results were analyzed by means of a mechanistic-empirical approach. Two test sections with wearing courses made of lime modified soil were built and monitored close to Cebollatí, a village in the east of Uruguay. Previously, laboratory characterization and mechanical tests on samples of the sedimentary soil were carried out. Lime contents for mixtures were determined and the stress-strain-strength behavior of mixes with different levels of lime content, curing time and compaction energy was studied. In order to analyze the elastic behavior of the lime modified soil under traffic, resilient modulus tests were carried out. This motivated the design, assembly and use of the first equipment for triaxial compression repeated loading tests in Uruguay. Besides, stress controlled fatigue tests were performed on cylindrical specimens of soil modified with 3% and 5% of lime, cured for 28 and 150 days. The results of laboratory tests and field monitoring were analyzed using computational models. In spite of the difficulties faced during pavements construction, including heavy traffic in early days, and the poor drainage, after 5 years of service no cracks or ruts are seen on top of the test pavements. Therefore, paving low volume roads in rice plantation areas with lime modified wearing courses has proved to be a cost-effective alternative, reducing construction and maintenance costs, and a sustainable practice, preserving non-renewable materials such as rocks and soils.
39

Controlling non-conformity propagation in low volume manufacturing / Controlling non-conformity propagation in low volume manufacturing

Fiegenwald, Valérie 18 September 2012 (has links)
Ce travail de thèse propose une approche pluridisciplinaire de la qualité dans les systèmes de production manufacturiers, couplant les approches d'ingénierie et de sociologie des organisations. Il s'intéresse aux risques de non-conformités qui peuvent se propager dans le processus de réalisation et atteindre le client final. Il est basé sur des études de cas réalisées chez Siemens E T HS (Energy Transmission High-voltage Substation), une entreprise produisant de faibles quantités de matériel haute-tension hautement personnalisé. Il propose tout d'abord une méthode qualité pour améliorer le système de détection des non-conformités en identifiant et en agissant sur ses faiblesses. Dans une deuxième approche, cette thèse propose des instruments organisationnels pour limiter la propagation des non-conformités entre les frontières organisationnelles et améliorer la résilience de l'organisation face à ces problèmes transfrontières. Les deux approches ont été mises en oeuvre dans l'entreprise étudiée puis étendues à une autre entreprise du groupe opérant sur le segment de la production de masse ce qui a permis de tirer des conclusions à la fois académiques et managériales pour les partenaires industriels. / This thesis proposes an interdisciplinary approach of quality in manufacturing production systems that combines quality engineering and organization studies. It is interested in the risk of non-conformities that can propagate in the delivery process and reach the final customer. It builds upon case studies conducted at Siemens ETHS, a company manufacturing low volumes of customized high-voltage equipment. First, a quality methodology is proposed to improve the detection system of non-conformities by identifying its weaknesses and acting on them. A second approach proposes organizational mechanisms to avoid non-conformity propagation between organizational boundaries and improve the organizational resilience in case of transboundary problems. Both approaches have been implemented in the company under study and then extended to another company of the group operating in the high volume field, what enabled the researcher to draw academic conclusions as well as to build practical knowledge for the industrial partners.
40

Avaliação de pulverizador tratorizado em volume ultra baixo (UBV) para controle de insetos de brotações novas, na cultura dos citros /

Silva, José Luiz da. January 2011 (has links)
Orientador: Marcelo da Costa Ferreira / Banca: Júlio César Galli / Banca: Hamilton Humberto Campos / Resumo: O objetivo desta pesquisa foi avaliar a eficiência, no controle de psilídeos, pulgão-marrom-dos-citros e minadora-das-folhas e também a seletividade a Pentilia egena, da aplicação terrestre em volume ultra baixo (UBV) em pomar de laranja. Foram realizadas 03 pesquisas, sendo que a primeira pesquisa foi realizada visando avaliar a mortalidade de adultos confinados do psilídeo e seletividade sobre a Pentilia egena na estação de pesquisa da Gravena Ltda em Jaboticabal-SP, a segunda pesquisa foi realizada visando avaliar a mortalidade de ninfas do psilídeo, pulgão-marrom-dos-citros e minadora-das-folhas em ramos novos em citros e a terceira pesquisa foi realizada visando avaliar a mortalidade de adultos confinados do psilídeo, sendo estas duas últimas realizadas na Fazenda Cachoeira do São Lourenço em Matão-SP. O delineamento estatístico adotado foi em blocos casualizados com número variável de tratamentos em cada pesquisa e quatro repetições. A aplicação da primeira pesquisa foi realizada no dia 25 de março de 2010, da segunda no dia 17 de novembro de 2010 e da terceira em 03 de maio de 2011, sendo usados nas pesquisas os seguintes produtos: Boveria bassiana (2,0 kg/ha), lambda- cialotrina (0,4 L/ha), dimetoato (2 L/ha), etofenprox (0,5 L/ha), thiamethoxan (0,2 kg/ha), Imidacloprid + espirotetramate (0,25 L/ha) e imidacloprido (0,4 L/ha) usando o pulverizador Pulsfog de volume ultra baixo (U.B.V.) comparado com o tratamento com imidacloprido (0,4L/ha) usando pulverizador com lanças manuais e de jato transportado. Baseado nos resultados obtidos pode-se concluir que os tratamentos, com volume ultra baixo (UBV), foram eficientes no controle de psilídeos, pulgão-marrom-dos-citros e minadora-das-folhas. Quanto à seletividade as modalidades de aplicação usadas foram classificadas de moderada a altamente tóxicos para as larvas e adultos de P. egena / Abstract: The purpose of this study was to evaluate the efficiency in the control of psyllids, citrus brown aphids and the citrus leaf-miner, and also the selectivity to Pentilia egena, by using ground application in ultra-low volume (ULV) in orchard orange. Three surveys were conducted, the first survey was conducted to evaluate the mortality of adult psyllids (Diaphorina citri) confined and selectivity on the ladybug (Pentilia egena) at the Research Station of Gravena Jaboticabal Ltda. The second survey was performed to evaluate the mortality of nymphs of the psyllid, the citrus brown aphid, and citrus leaf-miner in citrus and new branches. And, the third survey was conducted to evaluate the mortality of adults confined the psyllid, the latter being held in the Farm St. Lawrence Waterfall. The statistical design used was randomized blocks with variable number of treatments in each study and four replications. The implementation of the first survey was conducted on March 25th, 2010, the second on November 17th, 2010 and the third survey on May 3rd, 2011, being used in research the following products: Boveria bassiana (2.0 kg / ha), lambda-cyhalothrin (0.4 L / ha), dimethoate (2 L / ha), etofenprox (0.5 L / ha), thiamethoxan (0.2 kg / ha), Imidacloprid spirotetramat + (0, 25 L / ha) and imidacloprid (0.4 L / ha) using the sprayer Pulsfog ultra-low volume (ULV) compared to treatment with Imidacloprid (0.4 L / ha) using manual spray booms and jet transport. Based on the results obtained it is concluded that the treatments with ultra-low volume (ULV), were effective in controlling adults and nymphs of psyllids, citrus brown aphid and citrus leaf-miner. The selectivity of the used application methods was classified as moderate (M) to high (A) toxic to the larvae and adults of P.egena / Mestre

Page generated in 0.1379 seconds