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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

A lattice packing approach to an industrial cutting problem

Sparks, Christopher January 1991 (has links)
The thesis considers the action of the WI, and W2 wallpaper groups on a shape which is homeomorphic to the unit disc. A WI group is said to be optimal for a given shape if its action on the shape produces a packing which is at least as dense as any other WI packing. It is proved that for a given shape there must exist an optimal WI group. A set of necessary and sufficient conditions for a WI group to be optimal, for a given shape, are derived. An optimal W2 packing is defined in analogous manner. It is shown that for a given shape an optimal W2 group must exist. A set of necessary and sufficient conditions for a W2 group to be optimal, for a given shape, are derived. The thesis ends with conclusions and a number of suggestions for further work.
2

Comparative analysis of sizing in children's wear between the UK and Korea

Lim, Hye-Won January 2017 (has links)
The body shapes and sizes of children are distinctive and continually developing into adults' shapes. The sizing system for children's garments is not standardised between clothing companies and countries because to follow the national standard sizing system and to use the data of a national sizing survey is not compulsory for clothing companies. These factors bring about difficulties for garment makers for manufacturing appropriate sizes of clothing as well as for consumers while choosing the size of clothes in the global fashion market. For these reasons, a better understanding of body size and shape of children including their current sizing system and size charts is required. This research is based on in-depth empirical research comparing selected cases which are the UK and Korea. The aim was to provide a systematic technical guideline for garment makers by gaining a knowledge of current children’s body sizes and shapes and consequently providing an alternative set of data for the UK and Korea. Firstly, the main body shapes and sizes characteristics of infants and children including their growth rate, age classification, and gender differences were considered. Next, data of national sizing surveys and national sizing standards including the current brand size charts of infants and children’s clothing brands in the UK and Korea were compared and analysed by mixed methods. Also, consumer surveys were conducted and analysed to be aware of the difficulties in choosing sizes and purchasing tendencies of consumers. It was found that national sizing surveys and national sizing systems in the UK and Korea did not correspond significantly and it was referred that understanding of this contrasting designation and body measurement methods should be considered to explore each countries’ market. The different size chart constructing methods and body measurements between the two countries’ brand size charts also should be reflected for developing new size charts. It was also found that the considerably different consumer behaviour in the two countries should be recognised by garment manufacturers.
3

Penetration studies of vapours through protective clothing systems

Theotokatos, Spiridon January 1993 (has links)
No description available.
4

Optimisation of soft armour : a study of layering

Baker, Lisa Jayne January 2017 (has links)
Typical soft armour systems are constructed of multiple layers of a single fabric type. This empirical research sought to optimise these systems through hybridisation, sequencing dissimilar armour fabrics to maximise their ballistic protective performance. Eight individual plain weave fabrics with a spectrum of properties were manufactured from para- aramid and UHMWPE yarns and physical and ballistic characterisations were conducted. The ballistic impact tests established the specific energy absorption (SEA) of each fabric across a range of impact velocities (340 m s 1- 620 m-s'1) and the transverse displacement wave velocity across the rear of the fabric was found using digital image correlation. Low cover factor fabrics consistently showed faster transverse wave speed than the high cover factor fabrics (0.84 -0.96) for any given yarn type. The relative SEA of the fabrics varied dependent on both impact velocity and number of plies impacted. In general, the higher cover factor (0.84-0.96) fabrics, had greater SEA under low velocity (340 m-s'1) multi-ply impact conditions, and the low cover factor fabrics (0.74-0.84) had greater SEA across all the single ply impacts. Hybrid systems of the test fabrics showed significant difference in SEA dependent on layer order. The para-aramid hybrid systems impacted at 340 m-s'1, showed a significantly greater SEA when the fabrics were ordered with increasing rather than decreasing cover factor. At 620 m-s'1 the difference in SEA was less pronounced or was absent entirely. It was concluded that hybridisation would enhance the performance of a soft armour system and that this was likely to be most effective for the rear layers of the system where incorporation of fabrics with progressively increasing cover factor and manufactured of fine (550 dTex) para-aramid yarns would offer an advantage. The front layers of the system that are subject to higher strain loading would benefit from low cover factor fabrics (0.76) which maximise the dissipation of strain from the point of impact.
5

Development of a conceptual framework with a smart database for fabric sewability

McLoughlin, John January 2015 (has links)
Fabric sewability is an important element in garment manufacturing and has a critical impact on the aesthetic qualities and value of a garment. Garment manufacturers who fail to recognise and apply appropriate sewing practices incur huge inefficiencies in resources which can have both social and economic impact. The focus of this research was to bridge the gap between the human and machine interaction by understanding the fabric handle and creating an automated system to minimise sewing defects and maximise production. In doing this, a smart database was developed to predict lower and upper limits for sewing machine settings based on the mechanical and physical properties of the fabrics. The research further establishes the relationship between the fabric and the performance of the material during the sewing process. A feasibility study was undertaken to generate data on machine settings using woven shirt materials. These lightweight fabrics, with plain weave construction, were chosen as they generally exhibit higher levels of seaming problems during sewing. The relationship between the fabric parameters were examined, by using objective and subjective methods of assessment, to determine the physical and mechanical properties of the material. A technical expert, with extensive years of experience on stitching materials in the apparel industry, was invited to assess the materials and to offer their opinion on the potential sewability and recommend sewing machine parameters to produce a high quality seam. Based on the outcomes from the feasibility study, the research widened to a representative cohort of fabrics and examined the relationship between the mechanical properties and physical characteristics of the fabric and how they influence seam appearance and seam quality. A team of experts with specialist knowledge referred to as the ‘Sewing Parameter Evaluation Committee’ (SPEC) were invited to handle the materials and offer their advice on the machine settings to reduce seam deformation. Kendall’s coefficient of concordance was used to determine the level of alignment between the experts’ ranking of twenty fabrics and their suitability for a defect free seam. It highlighted that there was little agreement with the ranking of fabrics between experts. The fabrics were stitched using a standard lockstitch ISU (Integrated Stitching Unit) sewing machine and all the machine settings were adjusted manually. The expert opinions were collated based on their advice to establish the best possible settings to produce a garment with minimal seam deformation. The fabric intelligent technology system (FIT) was created to store the data and generate reports on machine settings for the sewability of the material by combining the validated SPEC recommendations and the fabric mechanical and physical properties. During the final phase of the project, a second set of experts (different from SPEC), were identified to rank the quality of the seams using the American Association of Textile Colourists and Chemists (AATCC) chart for seam deformation. The crux of this work was to develop a conceptual framework for a sewing machine settings database that would benefit the apparel industry by providing a knowledge based system for the optimisation of seam performance, quality and aesthetic appeal. The outcomes from this study add new knowledge to the body of literature that highlights the significance of fabric sewability in garment manufacturing and the limitations of predictive. The study also contributes to a greater understanding of the behaviour of textile materials during the sewing of garments and the application of machine settings which improve the manufacturing process of sewn seams. The framework underscores the significance of the robust system that reduces seam deformation, increases productivity, and facilitates the overall efficiency of the garment manufacturing process. The implementation of an efficient quality management system (QMS) is vital to the global economy and to the overall well-being of the workforce and this novel framework and system should contribute to the successful implementation of any QMS.
6

Protective materials for sporting applications : football shin guards

Ankrah, Stephanie January 2002 (has links)
No description available.
7

Ballistic impact of woven fabrics

Mansell, John January 1981 (has links)
No description available.
8

Development of 3D surfaces based on an energy model for woven fabrics

Chong, K. W. January 2002 (has links)
No description available.
9

Influencing ethical fashion consumer behaviour : a study of UK high street retailers

James, Alana January 2015 (has links)
This thesis explores the process of ethical fashion purchasing through a qualitative research approach, to find insights to improve the provision and purchasing of socially responsible fashion on the UK high street. This was achieved through the investigation of both the consumers that purchase womens wear at a mid market level, but also the retailers who provide the merchandise. The relationship between these two parties was explored, with the communication methods also being investigated. Furthermore, the influence the communication of retailer Corporate Social Responsibility (CSR) messages had on the final purchasing behaviour was also a key research area. This distinctive two-sided perspective was utilised to contribute to the creation of new knowledge in the area of ethical fashion purchasing behaviour, and consequently provide new perceptions of how positive, social changes can occur in the fashion industry. Much of the previous ethical fashion purchasing research has been criticized for several reasons including methodological weaknesses, survey instruments potentially overstating the importance of ethical issues, as well as participants having little to no incentive to answer truthfully (Auger and Devinney, 2007). As a result, researchers in this field have suggested that broader, more rigorous data collection tools need to be developed in order to advance this area of research (Dickson, 2011). With this in mind, a mixed method or bricolage approach (Kincheloe and Berry, 2004) was used to not only overcome the methodological issues identified, but to also address the knowledge gaps in a creative and innovative way (Bremner and Yee, 2011). As a consequence of using this approach, the interplay of data collection and analysis has resulted in an iterative process throughout the research undertaken. This iterative nature facilitated a five-stage data collection process, which included an ethnographic style case study with a major high street retailer, a consumer focus group and additional retailer, semistructured interviews. Between each of the five research stages, analysis and reflection took place, facilitating the development of the next data collection method. When addressing the study’s over-arching question: what influences ethical fashion purchasing, several factors were identified from both a consumer and a retailer perspective. It was found that whilst consumers do have a certain level of knowledge regarding social issues in the garment supply chain, they rarely implement this knowledge during their purchasing behaviour. The retailers surveyed, being evidenced in several of the additional interviews with CSR representatives, also identified this. However this lack of cohesion between consumer intentions and actual behaviour was found to be heavily influenced by the communication of CSR information from retailers to their customers. As a result, consumers were found to have a lack of understanding of social issues within the garment supply chain. Thus, it was concluded that the contribution to knowledge that this work makes is that an increase of retailer CSR communication, will aid in the development of a relationship between the consumer and supplier to increase connectivity, understanding and empathy, in order to influence ethical fashion purchasing. However, it is paramount that this CSR information is delivered in a simple way, in order for it to be understood by consumers. This was identified as an important factor due to a fundamental misunderstanding found in consumer understanding of the term ethical, and distinguishing this from closely related sustainable connotations. The approach and methodology utilised in this study was designed to address the problems identified in a new and innovative way, in order to lead to a series of new insights. The study of both the retailer and consumer simultaneously and the utilisation of creative methods attempted to provide a unique approach in dealing with the methodological issues previously mentioned. Due to the nature of the research, it has in the past been approached from a business or marketing perspective, however this study used creative skills and tools commonly used in design research. The value of this research has been evidenced in a results table, where the problems identified were addressed through a series of incremental stages towards change. These have been broken down into long and short-term changes, with the aim to gradually move the industry towards a more socially responsible future.
10

Breast support implications for female recreational athletes

White, Jennifer Louise January 2013 (has links)
Developing a scientific understanding of the breast support implications for the female recreational athlete will make a significant contribution to the breast biomechanics literature, provide valuable information to bra designers and help athletes make informed decisions about their breast support requirements. The work in this thesis determined the effect of a high and low breast support condition on biomechanical and perceptual variables during steady-state running, intermittent exercise and vertical jumping in a population of larger-breasted female recreational athletes. In order to assess breast kinematics an appropriate method of assessing bra fit was needed. Within this programme of research the use of best-fit criteria was first developed and then demonstrated that traditional bra fit methods overestimate band size (76% of participants) and underestimate cup size (84% of participants). During all activity modes a well-fitted high support bra significantly (p < 0.05) reduced breast kinematics and increased breast comfort. For steady-state running, alterations in lower-extremity biomechanics led to more distance being covered per minute (3.08 m; p = 0.006) and therefore a potential for improved performance when participants ran with high breast support. More acute knee flexion during sprinting (p = 0.008) and less sagittal plane thorax range of motion (p < 0.044) in the high breast support condition during the intermittent treadmill protocol could also benefit running performance. Increases in the range of motion of upper-extremity variables during treadmill activity were related to increases in some breast kinematic variables (r = 0.465 to 0.742); therefore certain individuals may require greater breast support than others. With increased breast kinematics there was a trend towards participants landing from vertical jumps with lower ground reaction forces coupled with increased thorax, thigh and knee flexion (r = 0.564 to 0.607). This suggests participants attempted to soften their landing, which may affect subsequent performance. Vertical jumping and sprinting elicited the highest magnitudes of vertical (0.08 m) and mediolateral (0.03 m) breast displacement respectively, questioning whether steady-state running is the most effective activity mode for testing bra efficacy. The reduction of anterioposterior breast kinematics should also be a consideration for bra design as they related most closely to breast comfort and biomechanical variables across all activity modes. Knowledge of the breast support implications for larger-breasted female recreational athletes was progressed in this thesis and bras offering high multi-planar support are promoted as they were found to be beneficial for performance within the activities investigated.

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