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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

An assessment of body weight perceptions, 'Fluffy' and the impact on psychological wellbeing and physical activity in Jamaica

Pearce, Venecia Ordell January 2017 (has links)
Body weight perceptions remain an important area of study. Beauty ideals have changed significantly with more emphasis on thinness. According to sociocultural perspectives, the pressure to be thin results in negative psychological consequences in most Western societies. Evidence, however, suggests that certain cultural and ethnic groups retain a traditional preference for plumpness. This thesis aimed to understand cultural perceptions of body weight and its influence on body dissatisfaction, self-esteem, body appreciation and physical activity in Jamaica. The research employed a mixed methodology approach. Qualitative inquiry using thematic analysis unearthed various beliefs about body weight and its health consequences. Specifically, it identified varying body ideals for women in Jamaica. These are the 'fluffy' body ideal and the slim ideal. The term 'fluffy' referred to women with larger bodies who were perceived to be confident and attractive. The novel Fluffy Rating Questionnaire (FRQ) was developed and was subjected to both exploratory factor analysis (parallel analysis) in study 2 and later confirmatory factor analysis in study 3. It was determined that the FRQ was best suited to examine impressions of fluffy women's personality which was a significant contribution to knowledge on fluffiness in Jamaica. Data were analyzed using Pearson's correlation, regression analysis, and analysis of variance. There were no relationships between impressions of fluffy women's personality, self-esteem, body appreciation or body dissatisfaction. However, the results support existing knowledge on the relationship between body mass index and body dissatisfaction, self-esteem and body appreciation. Impressions of fluffy were simulated and results suggest impressions of fluffy were related to lower recall of physical activity compared to impressions of obesity and the control. Overall, the findings indicate that there are influences of Western body ideals in Jamaica; however, there is still a traditional preference for plumpness which is conveyed through local expressions such as 'Fluffy'.
2

Catalytic Thermal Conversion of Kraft Lignin to Multi-Layer Graphene Materials

Yan, Qiangu 06 May 2017 (has links)
The objective of this research is to develop a scalable manufacturing process for high-volume production of low-cost graphene materials from lignin. The process includes preparation of catalyst-lignin precursors, pretreatment of precursors, and catalytic graphitization of kraft lignin to graphene materials. A growth concept, “catalytic thermal molecular welding (CTMW)” technique is proposed and validated to produce graphene materials from solid carbon resources. CTMW technique is a single process with two stages, i.e., the carbon-encapsulated metal nanostructures are first prepared. Then in the second stage these core-shell structures are opened by “scissoring molecules”, the cracked carbon shell units are welded and reconstructed to multilayer graphene materials under high temperature with selected “welding reagent gases” like light hydrocarbons (methane, natural gas, etc.) and hydrogen. Multi-layer nano-shell structure-based graphene materials, such as fluffy graphene, graphene chains, multi-layer graphene nanoplatelets, flatten or curved sheet-like graphene can be produced through altering fabrication conditions. The effects of transitional metal catalysts (Ni, Cu, Fe, and Mo) on the yields and structures of multi-layer nano-shell structure-based graphene materials from lignin are compared. The effects of the iron chemical resources (Fe(NO3)3, FeCl2, FeCl3, and Fe2O3 (nano)), iron loading on the yields and structures of multi-layer graphene materials from lignin are also examined. The influences of temperature, heating rate, heating time, metal-lignin precursor particle size, and welding reagent gas types on the yield of multi-layer graphene materials from lignin resources are investigated. Welding temperatures are optimized as1,000°C or above, with heating rates of 10°C or above. Welding gases including, argon (Ar), hydrogen (H2), methane (CH4), natural gas (NG), and mixed of these gases, are used at flow rates from 20 to 300 mL/min. Heating time is controlled between 0 to 5 hours. The effect of precursor particle size on final products is examined between 44 to 426 microns (Delta-m).

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