Signs are commonly used in the foodservice industry to portray food safety messages. However, many of these signs do not consider employee preferences or current needs in the industry. Employee perceptions can provide crucial information about the design of effective food safety messages. Surveys were conducted with meat and poultry processing employers in the mid-Atlantic region to determine food safety needs in the industry. Follow-up focus groups in both English (5) and Spanish (5) were conducted based on language availability and size. The most important food safety topics were hand washing (60.9%), cleaning/sanitizing (78.3%), and cross contamination (69.9%). Employees believe that color, text, and multiple language options could increase employee recognition and retention of intended messages. New, employee-driven hand washing signs were developed from the information in the focus groups. Signs were evaluated by video observation through five hand washing practice behaviors (soap use, complete wash, time to wash, complete rinse, and towel use) at two different poultry processing facilities in the mid-Atlantic at three different time points (baseline, short term, and long term). Soap use significantly increased at both facilities when baseline data was compared to short term and long term time periods. Facility B showed a significant increase in washing, time, and rinsing when baseline data was compared to short term, which indicates that a new sign could increase hand washing compliance. Sign color had a significant effect on behavior for washing and time of washing, while time had a significant effect on behavior for four of five variables tested. New signs could be a useful way to encourage compliance to food safety message for multicultural employees; however, they may need to be frequently changed as workers tend to refer back to old habits. / Ph. D.

Mechanized mining techniques that are commonly used in the coal industry produce a large amount of fine particles. These fines are extremely difficult to recover by conventional flotation methods, mainly because of the large size of the bubbles produced relative to the size of the particles. Hydrodynamic analyses have shown, however, that the use of smaller air bubbles can improve the flotation rate of these fines and, hence, the coal recovery. In the present work, a microbubble generator has been developed that produces bubbles smaller than 100 microns in diameter. Batch flotation tests conducted on samples from five different coal seams have demonstrated that the microbubble flotation process produces improved recoveries and often cleaner products than the conventional flotation process. The higher recoveries are a result of the increased bubble-particle collision efficiencies obtained with smaller bubbles, and also the larger number of bubbles produced in the microbubble process. The improved selectivity has been explained tentatively by the longer froth residence time in the microbubble process, along with the increased bubble loading and the reduced turbulence around the microbubbles. Various techniques have proven successful in further improving the selectivity by reducing the entrainment and/or entrapment of ash in the froth. To better understand the mechanisms of microbubble flotation, basic information regarding surface tension, contact angles, viscosity, streaming currents of microbubbles, electrophoretic mobilities of coal and mineral particles, and the stability of microbubble suspensions has been obtained using two non-ionic frothers. Microbubble flotation results obtained using each of these frothers have also been compared. / Master of Science

O presente estudo tem como objetivo avaliar o processo de purificação do biodiesel por adsorção, utilizando adsorventes alternativos de baixo custo, comparando a eficiência dos adsorventes selecionados com o método de purificação convencional (lavagem aquosa). Para tanto, foram realizados testes de triagem de materiais provenientes de resíduos industriais, avaliando a capacidade desses materiais na remoção de glicerol e recuperação mássica. Dentre os adsorventes testados, a cinza da casca de arroz e a argila chamo-te apresentaram melhores resultados, juntamente com a resina comercial Amberlite BD10DRY, utilizada como parâmetro de comparação nos ensaios de purificação por via seca. Por meio de planejamento experimental composto de face centrada 22, foi avaliado o efeito da concentração de cada adsorvente selecionado (2, 5 e 8% m/v) e a temperatura (30, 40 e 50 °C) nas variáveis respostas: percentuais de recuperação mássica e adsorção de glicerol. De acordo com a análise estatística foi possível estabelecer as condições operacionais para cada adsorvente que maximizam as variáveis respostas. As condições ótimas estabelecidas foram: concentração de adsorventes (3,7; 2,4 e 2,1% m/v) e temperatura (30, 45 e 30 °C) para a resina Amberlite BD10DRY, argila chamote e cinza de casca de arroz, respectivamente. Tais condições maximizaram a remoção de glicerol (entre 76 - 80%) sem ocasionar perdas elevadas de massa do adsorvato (3,0 - 6,5%). Para validar a metodologia de purificação por via seca, o procedimento foi testado em amostra de biodiesel etílico obtido em escala de laboratório, a partir de óleo de palmiste utilizando como catalisador óxido de nióbio impregnado com sódio. A purificação do biodiesel por adsorção foi realizada adotando as condições otimizadas, adotando a técnica de lavagem aquosa como método de comparação. Todos os métodos de purificação foram eficientes quanto à remoção de glicerol (abaixo do limite estipulado de 0,02% em massa) e todas as amostras purificadas apresentaram elevados teores de ésteres etílicos (EE%) variando entre 99,18% e 99,71% e valores de viscosidade cinemática (3,0-6,0 mm2/s) e densidade (850-900 kg/m3) dentro dos limites especificados pelas normas de qualidade estabelecidas pela Agência Nacional do Petróleo, Gás natural e Biocombustíveis (ANP) Resolução 45/2014. Entretanto, apenas as amostras purificadas por via seca utilizando argila chamote e cinza de casca de arroz apresentaram teores de monoacilglicerol e diacilglicerol dentro dos valores estipulados (0,70% para MAG e 0,20% para DAG). Estudos complementares da estrutura e composição dos adsorventes Cinza de casca de arroz e Argila Chamote foram efetuados para melhor compreender suas propriedades como agentes de adsorção. A capacidade de adsorção desses materiais está relacionada com o elevado conteúdo de sílica, como demonstrado pela difração de raios-x e análises de espectroscopia no infravermelho. Desta forma, resíduos de baixo custo e de elevada disponibilidade como argila chamote e cinza de casca de arroz, podem ser considerados como materiais promissores para serem usados em processos de purificação de biodiesel por via seca. / The present study aims at assessing the purification of ethyl biodiesel by dry washing using alternative low-cost sorbents, taking the efficiency demonstrated by a conventional purification method (wet washing) as a control parameter. Screening tests carried out with different sorbents (commercial and industrial wastes) revealed that rice husk ash and chamotte clay showed better results, along with the commercial resin Amberlite BD10DRY, used here as standard sorbent for dry washing. For the selected sorbents, a combined effect of sorbent concentration (2, 5, and 8 wt%) and temperature (30, 40 and 50° C) on the mass recovered and glycerol removal was studied using the response surface methodology. A 22 full-factorial central composite design was employed for the experimental design and analysis of the results. According to the statistical analysis it was possible to establish the operating conditions for each sorbent that maximize both responses. The optimum conditions were established at: concentration of sorbent (3.7; 2.4 and 2.1% m/v) and temperature (30, 45 and 30° C) for the resin Amberlite BD10DRY, chamotte clay and rice husk ash, respectively. Such conditions maximized the removal of glycerol (between 76-80%) and minimized the loss of the adsorbate mass (3.0-6.5%). Under optimal conditions, the sorbents were used for purifying ethyl biodiesel samples obtaining at laboratory scale from palm kernel oil using as catalyst niobium oxide impregnated with sodium. Both procedures (dry and wet washing) were quite efficient in removing glycerol (below the required limit of 0.02%) and all the purified samples showed high percentages of ethyl esters (EE%) ranging from 99.18% and 99.71% and values of kinematic viscosity (3.0-6.0 mm2/s) and density (850-900 kg/m3) within the limits specified by the quality standards established by the National Agency of Petroleum, Natural Gas and Biofuels (ANP) Resolution 45/2014. However, only the alternatives sorbents (chamotte clay and rice husk ash) were also able to remove monoacylglycerols (MG) and diacylglycerols (DG), thus their structures and compositions were further analyzed to better understand their properties as sorbents. The adsorption capacity of these sorbents is related to their high silica contents, as it was demonstrated by the X-ray diffraction and infrared spectroscopy analyses. Thus low-cost wastes such as chamotte clay and rice husk ash with high-availability features can be considered as a promising materials to be used in biodiesel purification processes by wet washing.

O presente estudo tem como objetivo avaliar o processo de purificação do biodiesel por adsorção, utilizando adsorventes alternativos de baixo custo, comparando a eficiência dos adsorventes selecionados com o método de purificação convencional (lavagem aquosa). Para tanto, foram realizados testes de triagem de materiais provenientes de resíduos industriais, avaliando a capacidade desses materiais na remoção de glicerol e recuperação mássica. Dentre os adsorventes testados, a cinza da casca de arroz e a argila chamo-te apresentaram melhores resultados, juntamente com a resina comercial Amberlite BD10DRY, utilizada como parâmetro de comparação nos ensaios de purificação por via seca. Por meio de planejamento experimental composto de face centrada 22, foi avaliado o efeito da concentração de cada adsorvente selecionado (2, 5 e 8% m/v) e a temperatura (30, 40 e 50 °C) nas variáveis respostas: percentuais de recuperação mássica e adsorção de glicerol. De acordo com a análise estatística foi possível estabelecer as condições operacionais para cada adsorvente que maximizam as variáveis respostas. As condições ótimas estabelecidas foram: concentração de adsorventes (3,7; 2,4 e 2,1% m/v) e temperatura (30, 45 e 30 °C) para a resina Amberlite BD10DRY, argila chamote e cinza de casca de arroz, respectivamente. Tais condições maximizaram a remoção de glicerol (entre 76 - 80%) sem ocasionar perdas elevadas de massa do adsorvato (3,0 - 6,5%). Para validar a metodologia de purificação por via seca, o procedimento foi testado em amostra de biodiesel etílico obtido em escala de laboratório, a partir de óleo de palmiste utilizando como catalisador óxido de nióbio impregnado com sódio. A purificação do biodiesel por adsorção foi realizada adotando as condições otimizadas, adotando a técnica de lavagem aquosa como método de comparação. Todos os métodos de purificação foram eficientes quanto à remoção de glicerol (abaixo do limite estipulado de 0,02% em massa) e todas as amostras purificadas apresentaram elevados teores de ésteres etílicos (EE%) variando entre 99,18% e 99,71% e valores de viscosidade cinemática (3,0-6,0 mm2/s) e densidade (850-900 kg/m3) dentro dos limites especificados pelas normas de qualidade estabelecidas pela Agência Nacional do Petróleo, Gás natural e Biocombustíveis (ANP) Resolução 45/2014. Entretanto, apenas as amostras purificadas por via seca utilizando argila chamote e cinza de casca de arroz apresentaram teores de monoacilglicerol e diacilglicerol dentro dos valores estipulados (0,70% para MAG e 0,20% para DAG). Estudos complementares da estrutura e composição dos adsorventes Cinza de casca de arroz e Argila Chamote foram efetuados para melhor compreender suas propriedades como agentes de adsorção. A capacidade de adsorção desses materiais está relacionada com o elevado conteúdo de sílica, como demonstrado pela difração de raios-x e análises de espectroscopia no infravermelho. Desta forma, resíduos de baixo custo e de elevada disponibilidade como argila chamote e cinza de casca de arroz, podem ser considerados como materiais promissores para serem usados em processos de purificação de biodiesel por via seca. / The present study aims at assessing the purification of ethyl biodiesel by dry washing using alternative low-cost sorbents, taking the efficiency demonstrated by a conventional purification method (wet washing) as a control parameter. Screening tests carried out with different sorbents (commercial and industrial wastes) revealed that rice husk ash and chamotte clay showed better results, along with the commercial resin Amberlite BD10DRY, used here as standard sorbent for dry washing. For the selected sorbents, a combined effect of sorbent concentration (2, 5, and 8 wt%) and temperature (30, 40 and 50° C) on the mass recovered and glycerol removal was studied using the response surface methodology. A 22 full-factorial central composite design was employed for the experimental design and analysis of the results. According to the statistical analysis it was possible to establish the operating conditions for each sorbent that maximize both responses. The optimum conditions were established at: concentration of sorbent (3.7; 2.4 and 2.1% m/v) and temperature (30, 45 and 30° C) for the resin Amberlite BD10DRY, chamotte clay and rice husk ash, respectively. Such conditions maximized the removal of glycerol (between 76-80%) and minimized the loss of the adsorbate mass (3.0-6.5%). Under optimal conditions, the sorbents were used for purifying ethyl biodiesel samples obtaining at laboratory scale from palm kernel oil using as catalyst niobium oxide impregnated with sodium. Both procedures (dry and wet washing) were quite efficient in removing glycerol (below the required limit of 0.02%) and all the purified samples showed high percentages of ethyl esters (EE%) ranging from 99.18% and 99.71% and values of kinematic viscosity (3.0-6.0 mm2/s) and density (850-900 kg/m3) within the limits specified by the quality standards established by the National Agency of Petroleum, Natural Gas and Biofuels (ANP) Resolution 45/2014. However, only the alternatives sorbents (chamotte clay and rice husk ash) were also able to remove monoacylglycerols (MG) and diacylglycerols (DG), thus their structures and compositions were further analyzed to better understand their properties as sorbents. The adsorption capacity of these sorbents is related to their high silica contents, as it was demonstrated by the X-ray diffraction and infrared spectroscopy analyses. Thus low-cost wastes such as chamotte clay and rice husk ash with high-availability features can be considered as a promising materials to be used in biodiesel purification processes by wet washing.

Thesis (MPH.) -- University of Limpopo, 2019 / Background: School children are mostly affected by diarrhoeal and respiratory infections and these are related to lack of proper hand washing. For children to be able to practice proper hand washing, they must have the knowledge and necessary resources to practice hand washing. The study’s purpose was therefore to establish the knowledge and practice of hand washing among primary school children. Purpose: The study’s aim was to assess the knowledge and practices of hand washing among primary school children in Kweneng Central Sub-District. Methods: A quantitative approach using a self-administered structured questionnaire to collect data regarding knowledge and practices on hand washing among primary school children was used. An observation checklist was also used to assess the practice of hand washing among primary school children. A stratified random sampling method was used to come up with a sample size of 330. SPSS 24.0 version was used to analyse the data. Results: The study revealed that the majority of primary school children had knowledge on hand washing but lacked proper hand washing practices. The results also showed that hand washing knowledge and practice among primary school children had no association with their age and gender. However, there was association between washing hands after going to the toilet and gender as well as the availability of bucket/basin to wash hands and gender. Conclusion: Children spend much of their day time at school; therefore schools are the right institutions to impart hand washing information and emphasise the importance of hand washing to the children. The availability of facilities such as clean water and soap are paramount to the facilitation of hand washing among primary school children and as such should be adequately provided in schools. Keywords: Hand washing, knowledge, practice, children, primary school.

The topic of this thesis is design of front-loading automatic washing machine and options to built-in installation and top panel removal. The thesis objective is to simplify and enhance control interface and make the interface ready for colour options. The thesis is divided to analytic portion and accompanying report. The analytic portion describes historical development, existing technical solutions and designs. The accompanying report describes design process since design alternatives evaluation. The final design itself consists of physical form, ergonomic, technical, colour and graphical solutions.

I den här studien analyseras företaget Gillettes visualisering av maskuliniteter i deras reklamfilm We Believe: The best men can be. Undersökningen utgår från hur företaget förhåller sig till genus efter rörelsen #metoo som slog igenom 2017. Genom en kvalitativ semiotisk analys, studeras utvalda klipp från reklamfilmen för att få en förståelse över symboler i reklamfilmen. De har sedan analyserats med hjälp av storytelling, representations teori och teoretiska begrepp, såsom maskulinitet, toxisk maskulinitet och woke-washing. Utifrån undersökningen ska en förståelse nås om Gillette som globalt företag har förändrat sin visuella kommunikation efter #metoo. Resultatet av studien är att Gillette inte skapar någon normbrytande gestaltning av maskulinitet. Istället visualiseras två olika former av maskuliniteter i reklamfilmen We Believe: The best men can be. Den första är en toxisk maskulinitet som Gillette tar avstånd från. Den andra är en traditionell hegemonisk maskulinitet, som bygger mycket på att en man ska beskydda och vara en förebild.

published_or_final_version / Community Medicine / Master / Master of Public Health

Diarrhea caused by rotavirus and Giardia is a major health problem among children attending day-care centers because of inadequate personnel hygiene. Epidemiological evidence suggesting person-to-person transmission of enteric pathogens has long been recognized. This study was initiated to investigate the effectiveness of handwashing for the removal of rotavirus and Giardia from contaminated hands. The palms of participant hands were innoculated with approximately 103 Giardia cysts or 105 plaque forming units of rotavirus and the effect of washing using tap water alone, a liquid soap or a bar soap on their removal was assessed. Handwashing with liquid soap was found to be very effective in the removal of rotavirus and Giardia cysts as compared to washing with bar soap or tap water alone. The overall recovery of viruses in both bar soap and liquid soap was low (0.03-22.5%), probably due to virus inactivation by the detergent.

The South African coal industry produces a large quantity of coal per annum. The rejects from various unit operations, such as spirals, consist of fine coal that joins the plants tailings dam waste. As existing high quality resources become depleted, the need to improve recovery of this fine coal grows. This project investigates the use of a teetered bed separator (TBS); a hindered settling gravity concentration device for fine coal recovery. This device has proven successful in the United Kingdom and in Australian collieries for fine coal separation in the size range between 2mm and 0.3mm. It has also been used for decades as a classifying device for silica sand and tin. The TBS operates in the size range of water-only cyclones and spiral concentrators, and could potentially be used to separate a broader size range of coal fines so as to offer a lower footprint device for the fines recovery section of a plant. Spiral concentrators cannot always be operated efficiently at a separating specific gravity of lower than 1.6; a TBS may also extend the density range for separation and thus improve recovery. The objective of this project was to gain a full understanding of the TBS from fundamental particle interaction and develop a lab scale unit, which is capable of separation to about 0.1mm at optimum conditions. This involved the development of design parameters based on the various distributor plates and flow pattern modelling. The hydrodynamics of the separator were investigated using the Eulerian-Eulerian modelling approach of commercial CFD package, Fluent 6.1. Seven distributor plates of varying aperture size and geometric arrangement were considered. Coal and shale particles, sized between 2mm and 0.038mm with a specific gravity (SG) range of 1.2 to 2.0, were separated using the laboratory scale unit. The results of both the simulations and the laboratory tests were then compared. The simulations revealed that Plate 3 was the best option for implementation. It had an even upward velocity profile compared to the other plates, with minimum wall effects and disturbances. The upward water flow rate (teeter water) was varied experimentally and the composition of the teeter bed, underflow and overflow were analysed using 1.5, 2 and Smm cubic density tracers with an SG range of 1.2-2.0. Analysis of the partition curves of the distributor plates revealed that Plate 3 had the lowest Ecart Probable (Ep) and cut- point densities. The comparison of simulated results and experimental results show that the simulator could predict the distributor plate design with the lowest Ep in practical tests. The simulator could be beneficial when optimising an industrial scale unit, by allowing prediction of improved segregation patterns and thus separation efficiency. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2005.