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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.
91

Mechanický návrh průběžného zásobníku příze a jeho realizace / Mechanical design and realization of the concurrent magazine for yarn

Klusoň, Vladimír January 2014 (has links)
This thesis deals with a Temporaryyarn storage device for yarn produced on an industrial loom. The Temporaryyarn storage contains a driven storage drum with a rotational yarn compensor. The driven rotating storage device is coupled with the first drive supplied by an electrical motor, and the rotational compensor is coupled with a second drive- also an electrical motor. The described Temporaryyarn storage can effectively increase the level of automation of an industrial loom.
92

Analysis of yarn properties in the superconducting magnetic bearing-based ring spinning process

Hossain, Mahmud, Abdkader, Anwar, Cherif, Chokri 05 November 2019 (has links)
The fundamental research work about the superconducting magnetic bearing (SMB) twisting system provides huge potential to eliminate the most important limitation of productivity, that is, the friction in the ring traveler system of the existing ring spinning process. As a continuity of the research work, the functionality of the SMB spinning has been carried out with different angular spindle speeds, yarn counts, and materials in order to determine the influence of the SMB technology. The current paper presents a comparative investigation of the yarn properties, such as yarn tenacity, yarn elongation, yarn evenness, microscopic views, etc., between conventional and SMB ring spun yarn. The intensive analysis confirms that the SMB system enables one to produce satisfactory yarn quality similar to that of conventional ring spun yarn up to 15,000 rpm. The influence of conventional and SMB spinning processes on yarn properties has been further analyzed statistically using an analysis of variance.
93

Konstrukce brzdičky příze s mechanickým přidržováním stroje Air-Jet / Construction of yarn keeper with mechanic clamp of Air-Jet machine

Jíša, Martin January 2016 (has links)
This diploma thesis describes methods of textile fibers treatment, production levels with detailed focus on spinning process especially by Rieter AG in Winterthur, Switzerland, subsidiary company in Usti nad Orlici. Thesis also describes production materials and it’s behavior in relations to production machines. Analysis of the current solution, it’s pros and cons is also done. Setting of requirements of new solution. Creating proposals of design solutions of yarn keeper with mechanic clamp situated on spinning unit on Air-Jet machine. Creating concepts and proposal schemes. After choosing of best possible solution considering production costs, electric consumption during working machine and during active cycle was this variation produce. At the end is review of complete solution and prospective next steps in testing not only in laboratory and prospects of using in field.
94

Image-Based Condition Monitoring of Air-Jet Spinning Machines with Artificial Neural Networks

Jansen, Kai January 2024 (has links)
This master thesis focuses on applying deep neural networks (DNNs) in image-based condition monitoring of air-jet spinning machines, specifically focusing on the spinning pressure parameter. The study aims to develop a sensor system to detect structural defects in yarns and assign them to specific machine conditions. The research explores using DNNs to analyze images of yarns generated at different spinning pressures within the spinning box to create a rich dataset for training deep learning models. The study also evaluates the effectiveness of the DNN-based approach in detecting and classifying structural defects in yarns and determining the corresponding machine conditions. The outcomes of this research could potentially help textile enterprises improve the quality and efficiency of their yarn manufacturing processes.
95

分散式計算系統及巨量資料處理架構設計-基於YARN, Storm及Spark / Distributed computing system and big data real-time processing structure—based on YARN, Storm and Spark

曾柏崴, Tseng, Po Wei Unknown Date (has links)
近年來,隨著大數據時代的來臨,即時資料運算面臨許多挑戰。例如在期貨交易預測方面,為了精準的預測市場狀態,我們需要在海量資料中建立預測模型,且耗時在數十毫秒之內。 在本研究中,我們將介紹一套即時巨量資料運算架構,這套架構將解決在實務上需要解決的三大需求:高速處理需求、巨量資料處理以及儲存需求。同時,在整個平行運算系統之下,我們也實作了數種人工智慧演算法,例如SVM (Support Vector Machine)和LR (Logistic Regression)等,做為策略模擬的子系統。本架構包含下列三種主要的雲端運算技術: 1. 使用Apache YARN以整合整體系統資源,使叢集資源運用更具效率。 2. 為滿足高速處理需求,本架構使用Apache Storm以便處理海量且即時之資料流。同時,借助該框架,可在數十毫秒之內,運算上千種市場狀態數值供模型建模之用。 3. 運用Apache Spark,本研究建立了一套分散式運算架構用於模型建模。藉由使用Spark RDD(Resilient Distributed Datasets),本架構可將SVM和LR之模型建模時間縮短至數百毫秒之內。 為解決上述需求,本研究設計了一套n層分散式架構且整合上列數種技術。另外,在該架構中,我們使用Apache Kafka作為整體系統之訊息中介層,並支持系統內各子系統間之非同步訊息溝通。 / With the coming of the era of big data, the immediacy and the amount of data computation are facing with many challenges. For example, for Futures market forecasting, we need to accurately forecast the market state with the model built from large data (hundreds of GB to tens of TB) within tens of milliseconds. In this research, we will introduce a real-time big data computing architecture to resolve requests of high speed processing, the immense volume of data and the request of large data processing. In the meantime, several algorithms, such as SVM (Support Vector Machine, SVM) and LR (Logistic Regression, LR), are implemented as a subproject under the parallel distributed computing system. This architecture involves three main cloud computing techniques: 1. Use Apache YARN as a system of integrated resource management in order to apply cluster resources more efficiently. 2. To satisfy the requests of high speed processing, we apply Apache Storm in order to process large real-time data stream and compute thousands of numerical value within tens of milliseconds for following model building. 3. With Apache Spark, we establish a distributed computing architecture for model building. By using Spark RDD (Resilient Distributed Datasets, RDD), this architecture can shorten the execution time to within hundreds of milliseconds for SVM and LR model building. To resolve the requirements of the distributed system, we design an n-tier distributed architecture to integrate the foregoing several techniques. In this architecture, we use the Apache Kafka as the messaging middleware to support asynchronous message-based communication.
96

Caractérisation du comportement mécanique longitudinale d'un fil de para-aramide en sollicitation dynamique / Characterization of the longitudinal mechanical behavior of a para-aramid yarn in dynamic load

Chevalier, Caroline 13 December 2016 (has links)
Ce travail a pour objectif d’étudier le comportement mécanique d’un fil de para-aramide en sollicitation longitudinale et dynamique. Pour ce faire, nous avons conçu un nouveau dispositif expérimental permettant de réaliser ces essais à l’aide d’un canon à gaz : le Dispositif de Traction par Impact sur Fil (DTIF). Ce dispositif a subi de nombreuses modifications dans le but d’obtenir des conditions d’essais optimales. Celui-ci est associé à un dispositif de mesure par laser permettant d’obtenir le profil de vitesse du projectile ainsi que les courbes caractéristiques de Force-Déformation du fil testé. La validité de la mesure est confirmée par comparaison aux résultats obtenus avec un vélocimètre à effet Doppler, dispositif permettant de mesurer directement et de façon précise le profil de vitesse du projectile. Plusieurs campagnes d’essais sont réalisées, à la fois dans le but d’identifier les caractéristiques dynamiques d’un fil seul, et dans le but de caractériser l’influence de l’arrangement structural d’un tissu sur le comportement dynamique d’un fil. Cette étude révèle l’intervention de trois principaux paramètres structuraux, qui sont la surface de contact inter-fils totale, le nombre de points de liage et les pressions inter-fils transverses et latérales au sein du tissu, influant sur quatre principaux critères de rupture du fil, qui sont les défauts de structure et les phénomènes d’hystérésis au sein du filament, les concentrations de contraintes ainsi que les forces de frottement au niveau des interactions entre le fil testé et le reste de la structure tissée. / This work aims at studying the mechanical behavior of a para-aramid yarn in dynamic and longitudinal load. To that end, we designed a new experimental device to achieve these tests with the use of a gas gun: the Tensile Impact Test for Yarn (TITY). This device met numerous modifications in the aim to reach optimal test conditions. It is associated with a measurement device using laser and allowing obtaining the velocity profile of the projectile and the Strength-Strain characteristic curves of the tested yarn. The validity of the measure is confirmed by comparing our results with those obtained with a laser Doppler vélocimètre, device allowing measuring directly and precisely the velocity profile of the projectile. Many test campaigns are performed. Both in the aim to identify the dynamic parameters of a single and virgin yarn, and in the aim to characterize the impact of the fabric structural arrangement on the dynamic behavior of a yarn. This study reveals the intervention of three main structural parameters, which are the total inter-yarns contact surface, the number of binding points and the transvers and lateral inter-yarns pressures, having an impact on four main yarn break criteria, which are the structural defects and hysteresis phenomena inside the filament, stress concentrations and frictional forces concerning the interactions between the tested yarn and the rest of the fabric.
97

Quantitative methods to characterize the impregnation of a glass multifilament yarn by a cementitious matrix

Aljewifi, Hana, Fiorio, Bruno, Gallias, Jean-Louis 03 June 2009 (has links)
This paper focuses on two experimental methods that give indicators linked to the impregnation level of the yarn / matrix interface, in the case of Textile Reinforced Concrete (TRC). These methods have been tested on three different glass yarns laid in a cementitious matrix, with three different impregnation levels resulting from the manufacturing process. The first method (comparative mercury intrusion porosity test) is based on the evaluation by mercury intrusion porosity of the pores volume associated to the porosity inside and near the yarn. The second method (flow test) consists in measuring the flow rate of water along the yarn, with imposed flow conditions. The physical parameters measured by these two methods are both related to the pore size and to the porosity of the yarn / matrix interface. The results of the two methods are discussed and drawn in parallel to a qualitative characterization of the yarn matrix interface made by scanning electron microscopy. As a result, the connection between the results of the two methods and the SEM characterization is studied. It is shown how these methods can participate to characterize the yarn impregnation. Limitations of the methods are also discussed.
98

Studies towards high-throughput production of nanofiber yarns

Smit, Eugene A. 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Electrospinning is a simple yet versatile method used for producing nanofibers from various materials, including natural and synthetic polymers, polymer blends, ceramics and metals. The high specific surface areas, high aspect ratios (length/diameter), and the biomimicking nature of nanofibers make them ideally suited for application in diverse areas, including high-performance filtration, biomedical materials for tissue engineering scaffolds, wound dressings and controlled drug release, fiber-reinforced composites and highly sensitive nano-sensors. Two of the main requirements that need to be met for electrospun nanofiber materials to become commercially viable are: (1) a process for manufacturing continuous aligned nanofiber yarns, and (2) a drastic increase in the fiber production rate of the electrospinning process. The objectives of this study were to develop a scalable process for making continuous yarns of aligned electrospun nanofibers, and to develop a needleless electrospinning method for the high-throughput production of nanofibers. Three novel processes were developed while exploring innovative ways for making yarns from electrospun fibers. Finally, a fourth process, the so-called the NanoCaterpillar process, was developed. This process can be used as a scalable method for obtaining continuous yarns of aligned nanofibers. Advantages of the process include the requirement for relatively simple equipment, the simple process variations required for obtaining yarns of different linear densities, and the fact that, as a 'dry' process, it can be used to manufacture yarns from most materials that can be electrospun. The second goal of this study was to develop a needle-less electrospinning process, capable of making nanofibers at commercially viable throughput rates. The phenomenon of bubble electrospinning was discovered and developed further. Initial exploratory studies showed that bubble electrospinning could be employed to produce nanofibers from polymers in aqueous as well as organic solutions, and that the process follows similar trends to classic electrospinning such as the dependence of fiber diameter on polymer solution concentration and the possibility of including substances in the formed fibers by including them in the spin solution. A second, more in-depth study of the bubble electrospinning process revealed that fibers could be produced at very high rates with estimates, under ideal spinning conditions, reaching 5 kg/h per square meter of bubble bath surface. Furthermore it was found that fiber yield did not depend on the size or the lifetime per bubble. Investigations into several interesting aspects of bubble and jet behaviour during bubble electrospinning, such as child bubble formation and jet-splitting, led to predictive multiple linear regression models being fitted to the experimental data to describe process variables like yield per bubble, number of jets per bubble and fiber diameters. / AFRIKAANSE OPSOMMING: Die elektrospintegniek is 'n eenvoudige, dog veelsydige metode wat gebruik word om nanovesels van verskeie materiale, insluitend natuurlike en sintetiese polimere, polimeermengsels, keramieke, en ook metale te vervaardig. Die hoë spesifieke oppervlakareas, hoë lengte tot deursnee verhoudings en bio-naboodsende eienskappe van nanovesels maak hulle ideaalgeskik vir toepassing in uiteenlopende velde soos filtrasie, biomediese materiale vir weefselingenieurswese, wondbedekkings en beheerde vrystelling van geneesmiddels, veselversterkte saamgestelde materiale en hoogs-sensitiewe nanosensors. Twee van die hoofvereistes waaraan voldoen moet word, voordat elektrogespinde nanovesels kommersieël-lewensvatbaar kan word, is: (1) 'n proses vir die vervaardiging van kontinuë garings van gerigte nanovesels, en (2) 'n drastiese toename in die vervaardigingstempo van die elektrospinproses. Die doelwitte van hierdie studie was om 'n skalleerbare proses te ontwikkel vir die vervaardiging van kontinuë garings van gerigte nanovesels, en om 'n naaldlose elektrospinmetode te ontwikkel vir die hoë-uitset vervaardiging van nanovesels. Drie nuwe prosesse is ontwikkel tydens ondersoeke na innoverende maniere om garings van elektrogespinde nanovesels te vervaardig. Laastelik is 'n vierde proses, die sogenaamde NanoCaterpillar proses ontwikkel. Hierdie proses kan gebruik word as 'n skalleerbare metode vir die vervaardiging van kontinuë garings van gerigte nanovesels. Voordele van die proses sluit in dat relatief eenvoudige toerusting benodig word om die konsep toe te pas, dat slegs eenvoudige veranderinge aan die proses benodig word om garings van verskillende liniêre digthede te verkry, en dat die proses, synde 'n 'droë' proses, gebruik kan word om garings te maak van meeste materiale wat gespin kan word met die elektrospintegniek. Die tweede doelwit van hierdie studie was om 'n naaldlose elektrospinproses te ontwikkel wat nanovesels kon vervaardig teen kommersieël-lewensvatbare tempo's. Die borrelelektrospin verskynsel is ontdek en verder ontwikkel. Aanvanklike ondersoeke het getoon dat die borrelelektrospinproses gebruik kon word om nanovesels te vervaardig van polimere in water- sowel as organiese oplossings. Dit het ook getoon dat die proses soortgelyke tendense toon as die klassieke elektrospintegniek, soos die afhanklikheid van veseldeursnee aan polimeeroplossingkonsentrasie en die moontlikheid om ander stowwe in die gevormde vesels in te sluit deur dit aanvanklik in die spinoplossing in te sluit. 'n Verdere indiepte ondersoek van die borrelelektrospinproses het onthul dat vesels, onder geïdealiseerde omstandighede, vervaardig kon word teen baie hoë tempo's, na beraming 5 kg/h per vierkante meter borrelbadoppervlakarea. Verder is bevind dat die veselopbrengs nie afhanklik was van die borrelgrootte of -lewensduur nie. Ondersoeke na verskillende aspekte van die borrel- en polimeerstraalgedrag tydens die borrelelektrospinproses, soos die vorming van kind-borrels en polimeerstraalsplitsing, het gelei tot die passing van voorspellende meerfoudige liniêre regressiemodelle op die eksperimentele data, ten einde prosesveranderlikes soos opbrengs per borrel, aantal polimeerstrale, en vesels deursnee te kan beskryf.
99

Yarn-forward production in a developing country : A case study conducted in Vietnam

Hjelte, Åsa, Letica, Daniella January 2016 (has links)
Purpose - The purpose of this paper is to identify the possibilities for a garment producing country, with high supplier and buyer dependency, to implement a yarn-forward value chain. Design/methodology/approach - This study analyzes existing literature along with collected data conducted through a field study in Vietnam. Primary data was collected through interviews with actors within the Vietnamese garment industry. Findings - What has been concluded through this case research is that monetary investments, relationships, and education of employees are dimensions that seem to be foundational in building a yarn-forward value chain successfully. Research limitations/implications - This study is limited to a specific case, only focusing on Vietnam's textile industry, meaning that the identified factors needed for establishing a yarn- forward value chain may differ depending on each country's native capabilities and access to raw materials. Practical implication - The findings of this study may contribute to an increased understanding of the surrounding factors regarding the implementation of yarn-forward production in a garment producing country. Originality/value - This study contributes to a deeper insight in what factors that affects a country’s garment industry and how a more competitive position can be created on the global textile market by taking these factors into consideration.
100

To study how to improve the productivity of yarn and fabric production in a production mill

MUHAMMAD, ASIF January 2011 (has links)
Productivity in every sector is essential, Production areas like textile require more production, more profit with less cost. Everyone should play their own role in achieving better production rate in these working sectors.There are many factors which can improve the productivity, but here we will focus on some specific areas. By working on these issues or factors, we can achieve our productivity goal. There are challenges for production managers and they need to take healthy measures for the enhancement in their production rates e.g. to find the best raw material available, to train its team and keep them updated to the latest technologies etc.This thesis is comprised of different factors which can affect the productivity in textile field. Here we will discuss the textile sector of Pakistan. All the information and collection of data is taken out and is referenced to the textile industry of Pakistan. / Program: Magisterutbildning i Applied Textile Management

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