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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.
1

Wet laid fibreglass composites

Siddique Yousfani, Sheraz January 2010 (has links)
This study investigated the manufacturing process of thermo-set fibreglass nonwoven composites. Techniques of manufacturing nonwoven webs from chopped strands were investigated and from the literature review it was found that the wet laid method was appropriate. The process of manufacturing paper hand sheets from pulp was modified to manufacture flat fibreglass nonwoven webs. The effects of dispersion and fibre length on the quality of these webs were investigated. It was found that the quality of these webs improved due to the dispersion.These nonwoven webs were then impregnated with epoxy resin by using the resin infusion method of vacuum bagging to make composite samples. The effects of dispersion, fibre length and multiple layering on the quality and mechanical properties of these composites were studied. It was found that it is necessary to disperse the fibreglass strands in order to manufacture composites of better quality. The quality and strength of these composites also improved due to the increase in the fibre length and multiple layering. Some initial studies were done to manufacture 3D fibreglass nonwoven webs by using the vacuum forming technique and 3D fibreglass nonwoven composites were also made using these webs. Initial investigation of the physical properties of these 3D composites was conducted and it was found that the void content decreased and the density had slightly increased due to the multiple layering process. This topic can be further investigated in the future.
2

A Study of the Labor Mobility and the Laid-off Workers of State-Owned Enterprises in China.

Shen, Tung-wei 27 June 2006 (has links)
This paper primarily concentrates on the causation of labor mobility and laid-off workers in China. In order to realize the causation of the Chinese labor mobility in urban and rural China after 1978, this paper has collected data and materials about institutional changes of labor management in China. This paper has found that China¡¦s rural labor migration to the urban labor market has been steadily rising. Because of the gap between urban and rural wages, pressures on the urban job market have increased, while urban labors migrating to the rural job market has been minimal. The institutions for labor management in China have undergone changs, and although central and local authorities have inacted various restrictions on labor migration, these restrictions have been a statistic bias and lacked in real effects.
3

Investigation of the binding effect of fungal fiber (grown on apple pomace) in the formation of lyocell nonwoven textiles and their potential applications

Luo, Xue January 2021 (has links)
This project combines nonwoven technology, biological technology and food waste management and seeks for this feasibility to use fungal microfiber (FM) as a binder for lyocell pro-duction and the characterizations for possible applications. Rhizopus delemar was cultivated apple pomace in liquid-state fermentation to obtain mycelia biomass. The biomass was later blended in a kitchen blender for one minute. The blended FM was later mixed with 6 mm lyocell fibre at different FM dry weight percentage and water to make nonwoven webs by wet-laid method. The feasibility of using fungal microfiber as a binder for lyocell nonwovens was confirmed in this study. It is not possible to make nonwoven webs using lyocell short fibre without any binder applied. With 5%_FM, the tensile strength of lyocell nonwoven webs reached 0.0989 MPa. A clear increasing tensile strength was recorded as the increasing of FM weight per-centage and resulted a highest tensile strength at 9.38 MPa when applying 60%_FM. The re-sult of water contact angle proved that the increasing FM could decrease the hydrophobicity of nonwoven samples. Abrasion test showed that FM could improve the abrasion resistance of the lyocell nonwoven samples. Porosity test showed that lyocell nonwoven samples with a higher FM ended up with smaller mean flow pore size diameter (MFP) that nonwoven samples with 65%_FM has an average MFP at 7.26 m m. The SEM images reviled that FM bonded nonwoven webs had a fibrous structure, which is due to binding effect of fungal microfiber on lyocell short fibers. These characterizations have demonstrated the mechanism of using fungal microfiber as a binder for lyocell nonwovens in this project. In this thesis project, FM bonded lyocell nonwoven webs showed a great potential on the application of nonwoven applications such as interior materials or filtration materials.
4

Preparation of films and nonwoven composites from fungal microfibers grown in bread waste

Köhnlein, Maximilian January 2020 (has links)
Unsold bread makes up a signification fraction of waste occurring in Swedish supermarkets. This thesis seeks to address the problem of food waste, by cultivating filamentous fungi on bread waste and producing chitinous films and nonwovens from them. Rhizopus delemar was cultivated on bread waste in liquid-state fermentation in order to obtain mycelia biomass. The biomass was processed by alkali or protease treatments to disrupt the fungal cells and remove proteins and fats. Afterwards it was subjected to a bleaching treatment to remove lignin fractions of bread residues. The treated biomass was then subjected to a grinding treatment for a homogeneous dispersion of mycelial fibers, where the dispersion was confirmed by microscopic images. The chemically and mechanically processed biomass was used for the preparation of films and nonwoven composites by employing a wet-laid papermaking process. The films exhibited plastic-like features, due to their brittleness and their smooth upper surface. Films and nonwoven composites were characterized on their tensile properties, surface water contact angle and their surface morphology by scanning electron microscopy. Treating fungal biomass by alkali and then bleaching resulted in films with atensile modulus of 3.38 GPa and an ultimate tensile strength of 71.50 MPa. These are the highest reported tensile properties for mycelia derived films to date. Water contact angle measurements confirmed a hydrophobic quality of mycelial films. Scanning electron microscopy showed a very dense and even surface without an obvious fibrous morphology. Fungal biomass and viscose fibers together form a rigid nonwoven composite, in which fungal biomass takes over the role of a natural eco-friendly binding matrix. Flexural rigidity measurements were out of bounds and need to be confirmed by future studies. Additionally, a second strain of fungi, Fusarium venenatum, was cultivated on bread particles in water suspension in order to determine optimum growth conditions for future scale-up investigations.
5

Biokonvertering av Brödavfall till Svampfilmer för Textila Applikationer / Bioconversion of Bread Waste to Fungal Films for Textile Applications

Syed, Samira January 2023 (has links)
Bread waste represents a significant portion of global food waste, necessitating innovative approaches for its valorization. This research project explores the utilization of bread waste through fermentation with Aspergillus oryzae to produce fungal film which could be used for textile applications. While previous studies have examined various applications of food waste, this project specifically targets the textile industry, aiming to mitigate pollution associated with conventional textile manufacturing. The objective of this project was to investigate the feasibility of creating fungal films derived from bread waste. Additionally, to analyze the material's properties through assessments of tensile strength, microscopic analysis, and the identification of an appropriate methodology for this investigation. The biomass suspension was prepared using an ultrafine grinder, and a kitchen blender was subsequently employed to minimize the presence of remaining solids from the grinding process. Additionally, a range of strategies for film casting and wet laying were implemented and evaluated. Wet laying involved combining fungal biomass with tannin to mimic the characteristics of leather. On the other hand, casting utilized pre-treated biomass suspension to assess the formation and quality of the films. As the research progressed and different tannins were used to treat the biomass, a methodology was developed, and glycerol was introduced as a plasticizer. Furthermore, nanocellulose was later incorporated exclusively for the casting of the films to serve as a binder. The films that were produced gave interesting results are observed in casted sheets containing nanocellulose and glycerol-infused biomass (3% BM + 2% Cellulose + 0.13 g Glycerol), exhibiting exceptional tensile strength (35.1 ± 3.42 MPa) and elongation (16.7 ± 5.98%). Wet laid biomass sheets treated with Tara and glycerol display tensile strength (19.9 ± 3.55 MPa) and elongation (6.66 ± 3.02%). These findings signify the potential for developing fungal films from bread waste, necessitating further research to refine methodologies. Overall, this research project paves the way for future advancements in fungal films derived from bread waste. By investigating the use of Aspergillus oryzae and employing wet laying and casting techniques, the project establishes a foundation for sustainable textile production. The successful utilization of bread waste not only addresses the issue of food waste but also contributes to reducing pollution in the textile industry.
6

Průzkum tržní orientace našich firem / Research on market orientation of our firms

Vlasová, Tereza January 2008 (has links)
The thesis deals with the market orientation of high-tech companies based in the city of Brno. It measures the effects of market orientation on business performance, analyzes the relations between market orientation and business performance for chosen companies and evaluates logical structure of the questionnaire used for marketing research. Based on the results of the research the thesis contains solution proposals addressed to the given companies, points out their weaknesses and follows with the proposals for the structure of the questionnaire and its future application for researching market orientation of the companies.

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