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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

Efficiency optimisation in a DC-DC chopper motor drive

Prest, Rory Bruce 02 October 2023 (has links) (PDF)
A complete DC-DC motor drive (battery, chopper, and motor) - is investigated with a view to optimising efficiency. The losses at each stage are analysed in detail and proposals are made to minimise them. The overall system is also modelled for the purpose of computer simulation. The computer model is used to investigate the possible efficiency saving if both field and armature current are controlled. An optimum control system is developed and compared with other control systems.
2

What happens in the shadows? : A quantitative analysis on the effect of shadows in baseball.

Ström, Martin January 2021 (has links)
Baseball is one of the most statistically documented sports in the world. Every statistical outcome in baseball starts with the pitcher and the plate appearance. In baseball, it is believed that when shadows are present between the pitcher’s mound and the batter’s box, the pitcher is at an advantage. Therefore, the aim of the study was to identify if there is an advantage for pitchers pitching with shadows separating the pitcher’s mound from the batter’s box. Only games from Major League Baseball in which the shadows were present between the pitcher’s mound and batter’s box were analyzed. Analyzed variables were comprised of traditional statistical outcomes categorized as good or bad outcomes. Furthermore, good and bad outcomes were analyzed using their ordinal subcategories rated from 1 to 4. Differences between good and bad outcomes of plate appearances, when shadows were and were not present, was analyzed using a Mann-Whitney U Test.  The results of the study indicate that shadows do not have a significant effect on the outcome of plate appearances. Moreover, pitchers do not have an advantage pitching while shadows are present between them and the batter’s box. Frequencies of outcomes with shadows present was much the same to outcomes without the shadows present. In conclusion, it does not appear that shadows influence the outcome of plate appearances. However, further research on statistical metrics and their effect on plate appearances is necessary.
3

Potencialidades da succinil quitosana como emulsificante e substituto de fração lipídica em massa de bolo / Potentialities of succinyl chitosan as emulsifier and lipid fraction substitute on cake batter

Rios, Raquel Vallerio 17 December 2018 (has links)
A necessidade da criação de produtos inovadores com características funcionais está relacionada com a demanda de consumidores que priorizam o bem-estar vinculado a uma alimentação saudável e equilibrado. Nesse sentido, o objetivo deste estudo foi avaliar os efeitos da adição de succinil quitosana (SQ) como um substituto da fração lipídica e agente emulsificante sobre a qualidade de bolos. Para tanto, no capítulo 1 foi realizado um levantamento conciso da literatura para a compreensão dos temas abordados. No capítulo 2, o estudo da SQ se baseou na sua obtenção e caracterização para aplicaçãoem bolos. A análise de infravermelho e difração de raio X validaram as reações de desacetilação e succinilação, sendo que os estudos térmicos demonstraram estabilidade térmica (acima de 300 °C) viabilizando a utilização da SQ em produtos de panificação. A aplicação da suspensão de SQ (2,0 g/100 g) em massas de bolos com níveis reduzidos de gordura (0 % (controle), 25 %, 50 %, 75 % e 100 % (ausência total de gordura)) com ajustes na quantidade de água, para adaptação das consistências das massas, resultou em massas de bolos com parâmetros de viscosidade semelhantes. A redução de gordura até um nível de 50 % e presença de SQ contribuiu para o aumento da área 2D (de 13, 83 para 19,05 mm2) e razão largura/altura, além da umidade e atividade de água. A SQ influenciou significativamente (p < 0,05) na vida de prateleira, visto que a taxa de endurecimento foi de 27,8 (N/dia) para os bolos controle, e em bolos com nível de 25 % apresentou o valor de 26,1 (N/dia) e 49,2 (N/dia) para àqueles com presença total de SQ. Os teores de lipídeos diminuíram significativamente (p < 0,05), embora o conteúdo total de minerais e proteínas tenham apresentado ligeiras variações. Em relação à análise sensorial, foram atribuídas aos bolos com redução de até 50 % de gordura notas entre 6 e 7, e àqueles com 75 % de redução, nota inferior para os atributos de textura, sabor e aspecto geral. Dos provadores, 35 % \"provavelmente comprariam\" os bolos com 50 % de gordura. Nesse sentido, a SQ pode ser considerada um potencial substituto de gordura em bolos, podendo-se reduzir à metade a quantidade deste ingrediente em sua formulação original, agregando qualidades tecnológicas, sensoriais e nutricionais a esses produtos. / The need to create innovative products with functional characteristics is related to the demand of consumers which prioritize the well-being combined to a healthy and balanced diet. In this sense, the objective of this study was to evaluate the effects of the addition of succinyl chitosan (SQ) as an emulsifying agent and lipid fraction substitute on the qualities of cakes. Therefore, in chapter 1 a concise survey of the literature was carried out to understand the themes covered. In chapter 2, the SQ study was based on its obtaining and characterization for application in cakes. Infrared analysis and X-ray diffraction validated the deacetylation and succinylation reactions, and the thermal studies demonstrated thermal stability (above 300 °C), allowing the use of SQ in bakery products. The application of SQ suspension (2.0 g / 100 g) with reduced levels of fat (0 % (control), 25 %, 50 %, 75 % and 100 %) adjusting the amount of water, to adapt the batter\'s consistencies, resulted in cakes with similar viscosity parameters. The reduction of fat up to 50 % and presence of SQ contributed to the increase of the 2D area (from 13,83 to 19,05 mm2) and width / height ratio, as well as moisture and water activity. SQ significantly influenced (p <0.05) shelf life, since the hardening rate was 27,8 (N / day) for control cakes, and in cakes with a 25% level the value was 26,1 (N / day) and 49.2 (N / day) for those with total presence of SQ. The lipid contents decreased significantly (p <0.05), although the total content of minerals and proteins showed slight variations. Regarding sensory analysis, scores between 6 and 7 were attributed to cakes with a fat reduction of up to 50%, and those with a 75% reduction were attributed a lower score, according to the attributes of texture, taste and overall appearance. From consumers, 35% \"I would probably purchase\" the cakes with 50% fat. In this sense, SQ may be considered a potential substitute for fat in cakes, and it can reduce the amount of this ingredient by half in its original formulation, adding technological, sensorial and nutritional qualities to these products.
4

Potencialidades da succinil quitosana como emulsificante e substituto de fração lipídica em massa de bolo / Potentialities of succinyl chitosan as emulsifier and lipid fraction substitute on cake batter

Raquel Vallerio Rios 17 December 2018 (has links)
A necessidade da criação de produtos inovadores com características funcionais está relacionada com a demanda de consumidores que priorizam o bem-estar vinculado a uma alimentação saudável e equilibrado. Nesse sentido, o objetivo deste estudo foi avaliar os efeitos da adição de succinil quitosana (SQ) como um substituto da fração lipídica e agente emulsificante sobre a qualidade de bolos. Para tanto, no capítulo 1 foi realizado um levantamento conciso da literatura para a compreensão dos temas abordados. No capítulo 2, o estudo da SQ se baseou na sua obtenção e caracterização para aplicaçãoem bolos. A análise de infravermelho e difração de raio X validaram as reações de desacetilação e succinilação, sendo que os estudos térmicos demonstraram estabilidade térmica (acima de 300 °C) viabilizando a utilização da SQ em produtos de panificação. A aplicação da suspensão de SQ (2,0 g/100 g) em massas de bolos com níveis reduzidos de gordura (0 % (controle), 25 %, 50 %, 75 % e 100 % (ausência total de gordura)) com ajustes na quantidade de água, para adaptação das consistências das massas, resultou em massas de bolos com parâmetros de viscosidade semelhantes. A redução de gordura até um nível de 50 % e presença de SQ contribuiu para o aumento da área 2D (de 13, 83 para 19,05 mm2) e razão largura/altura, além da umidade e atividade de água. A SQ influenciou significativamente (p < 0,05) na vida de prateleira, visto que a taxa de endurecimento foi de 27,8 (N/dia) para os bolos controle, e em bolos com nível de 25 % apresentou o valor de 26,1 (N/dia) e 49,2 (N/dia) para àqueles com presença total de SQ. Os teores de lipídeos diminuíram significativamente (p < 0,05), embora o conteúdo total de minerais e proteínas tenham apresentado ligeiras variações. Em relação à análise sensorial, foram atribuídas aos bolos com redução de até 50 % de gordura notas entre 6 e 7, e àqueles com 75 % de redução, nota inferior para os atributos de textura, sabor e aspecto geral. Dos provadores, 35 % \"provavelmente comprariam\" os bolos com 50 % de gordura. Nesse sentido, a SQ pode ser considerada um potencial substituto de gordura em bolos, podendo-se reduzir à metade a quantidade deste ingrediente em sua formulação original, agregando qualidades tecnológicas, sensoriais e nutricionais a esses produtos. / The need to create innovative products with functional characteristics is related to the demand of consumers which prioritize the well-being combined to a healthy and balanced diet. In this sense, the objective of this study was to evaluate the effects of the addition of succinyl chitosan (SQ) as an emulsifying agent and lipid fraction substitute on the qualities of cakes. Therefore, in chapter 1 a concise survey of the literature was carried out to understand the themes covered. In chapter 2, the SQ study was based on its obtaining and characterization for application in cakes. Infrared analysis and X-ray diffraction validated the deacetylation and succinylation reactions, and the thermal studies demonstrated thermal stability (above 300 °C), allowing the use of SQ in bakery products. The application of SQ suspension (2.0 g / 100 g) with reduced levels of fat (0 % (control), 25 %, 50 %, 75 % and 100 %) adjusting the amount of water, to adapt the batter\'s consistencies, resulted in cakes with similar viscosity parameters. The reduction of fat up to 50 % and presence of SQ contributed to the increase of the 2D area (from 13,83 to 19,05 mm2) and width / height ratio, as well as moisture and water activity. SQ significantly influenced (p <0.05) shelf life, since the hardening rate was 27,8 (N / day) for control cakes, and in cakes with a 25% level the value was 26,1 (N / day) and 49.2 (N / day) for those with total presence of SQ. The lipid contents decreased significantly (p <0.05), although the total content of minerals and proteins showed slight variations. Regarding sensory analysis, scores between 6 and 7 were attributed to cakes with a fat reduction of up to 50%, and those with a 75% reduction were attributed a lower score, according to the attributes of texture, taste and overall appearance. From consumers, 35% \"I would probably purchase\" the cakes with 50% fat. In this sense, SQ may be considered a potential substitute for fat in cakes, and it can reduce the amount of this ingredient by half in its original formulation, adding technological, sensorial and nutritional qualities to these products.
5

John Donnes poetiska teknik : - två små nedslag -

Sirelius, Julia January 2007 (has links)
No description available.
6

Effects Of Different Batter Formulations On Quality Of Deep-fat Fried Chicken Nuggets

Dogan, Seyhan Firdevs 01 July 2004 (has links) (PDF)
The main objective of this study was to evaluate the effects of different flour and protein types on quality of deep-fat fried chicken nuggets. Additionally, the rheological properties of batters were studied and the batter viscosity was correlated with fried product quality. In the first part of the study, the effects of soy and rice flour (5%) addition to the batter formulation on product quality were studied. Coating pick-up of batters, and moisture content, oil content, texture, color, volume, porosity, and cooking yield of nuggets were determined for 3, 6, 9 and 12 minutes of frying times at 180&ordm / C. In the second part of the study, the effects of protein types (soy protein isolate, whey protein isolate and egg albumen) at different concentrations (1 and 3%) on quality attributes were studied. A batter formulation with no flour or protein addition was used as control. In both parts of the study, flow behavior of batters prepared using different flour and protein types were determined. Soy flour and soy protein isolate (SPI) provided the highest apparent viscosity. Batter viscosity was found to be correlated with coating pick-up. All batters were found to show thixotropic behavior. The batters were modeled as power-law fluid and all of them turned out to be shear-thinning except egg albumen added batter, which was shear-thickening. As a result of the study, among the flour and protein types used, 3% whey protein isolate (WPI) was found to be the most effective ingredient on improving quality parameters of deep-fat fried chicken nuggets. 3% WPI added batters provided the hardest and crunchiest product with the darkest color. It also reduced the oil content of fried nuggets significantly. However, low cooking yield values were observed for batters with 3% WPI. On the other hand, soy flour containing batters provided high cooking yield. Therefore, if high cooking yield with low oil content is desired, soy flour can be advised to be used in batter formulations for chicken nuggets.
7

Effects Of Different Batter Formulations On Quality Of Deep-fat Fried Carrot Slices

Akdeniz, Neslihan 01 August 2004 (has links) (PDF)
The main objective of the study was to evaluate the effects of starch and gum types on product quality of deep-fat fried carrot slices. It was also aimed to evaluate the applicability of image processing for determination of oil uptake. In the first part of the study, carrot slices were dipped into batters containing three different concentrations of dextrin or pre-gelatinized tapioca starch and fried for 2, 3, and 4 minutes at 170&plusmn / 2 oC. Coating pick-up of batter formulations and moisture content, oil content, frying yield, bulk density, porosity, texture and color of fried slices were evaluated. In the second part of the study, the effects of different gum types (HPMC, xanthan gum, guar gum, guar-xanthan gum combination) on quality attributes were studied. No starch or gum added coating formulation was used as the control. Finally, images of carrot and batter sections of the fried samples were obtained using digital camera and area fractions of oil droplets were determined using image processing. Acceptable product quality was obtained at higher concentrations of pre-gelatinized tapioca starch. On the other hand, increasing dextrin concentrations had an adverse affect on the product quality. As a result of the study, guar-xanthan gum combination has been found as the most effective additive on the batter performance. This additive provided the highest moisture content, lowest oil content, highest volume and lightest color to the product after frying. The porous and crunchy structure obtained using this combination was at the acceptable level for deep-fat fried products. Determination of area fraction of oil droplets on carrot and batter surfaces of fried samples using image processing was correlated with the oil content of fried product at initial stages of frying. The correlation coefficient between moisture content and frying yield was found as 0.90. A correlation was also determined between oil content and moisture content (r= -0.88).
8

The Influence of Support Conditions on Hit Speed in Baseball

Dillard, Jeffrey Stephen 10 May 2003 (has links)
This paper is an investigation into the effect of the bat support conditions on the collision between a baseball and a baseball bat. Bat performance is tested using both machines and human subjects. For the machine tests, a baseball is fired from an air-cannon at a stationary bat, where the bat is either allowed to rotate only or is completely unrestricted after impact. The initial and rebound ball speeds are measured for a range of impact locations. For the human tests, a person swings the bat and hits the ball off of a tee. The bat speed prior to impact and the ball speed after impact are measured. The results for each method of testing are compared, and the final ball speed is found to be independent of the bat support condition.
9

Tracking a Baseball During a Color Naming Task

Young, Josiah W. 26 August 2009 (has links)
No description available.
10

DUPLA MODIFICAÇÃO QUÍMICA DE AMIDO DE FEIJÃO, AVALIAÇÃO DAS PROPRIEDADES TECNOLÓGICAS E APLICAÇÃO EM MATRIZ PROTEICA

Wojeicchowski, José Pedro 20 February 2017 (has links)
Made available in DSpace on 2017-07-21T18:53:08Z (GMT). No. of bitstreams: 1 Jose Pedro.pdf: 2190334 bytes, checksum: 091c9d7fac9a1c0a497c54fbd8c1584f (MD5) Previous issue date: 2017-02-20 / Common beans are highly consumed in Brazil, mainly in complement with rice. It is a nutritious food source, riches in carbohydrates that represent 60% of the dry weight of the grains which starch is the largest fraction. Starch is a natural polymer of glucose and it is considered as an energy reserve of the higher vegetables. Found as semicrystalline granules, starch is a mixture of amylose and amylopectin molecules and this one has a greater content. In its native form, starch presents limited application, especially as a binding agent, due their low thermal resistance and high tendency to retrograde. Therefore, physical and/or chemical modifications can be applied in order to improve technological properties, making starch viable at industrial level. The present study aimed to extract bean starch, analyze their physical-chemical and technological properties, modify by oxidation, acetylation and dual-modification, as well as their application in breaded products. The X-ray diffractograms showed that bean starch has a type C, typical of legumes. Images of electron microscopy revealed that the granules has an oval and elliptical shape. The oxidation of the starch was evidenced by the increase of carbonyl and carboxyl contents. Acetylated samples presented a low degree of substitution, that allow food application. Substitution of hydroxyls was proved by acetyl groups that exhibits bands in the region of 1735-1740 cm-1. Modified starches showed changes in their technological properties. Oxidized sample presented increase of the peak and setback viscosity, due carboxylic groups. The acetylated starch presented cooking stability, due their low breakdown viscosity. Enthalpies of gelatinization of the modified samples reduced, in function of weakening of the granular structure. Relative crystallinity, hardness and adhesiveness of the gels, also reduced. Application of bean starch in breaded products exhibited interesting results. The system with oxidized starch resulted in the most crust covered area after frying, 72%. Breaded meat presented yield up to 100%, that means weight gain during the process. The pick-ups values of samples with starch were less than 30%, then the fried products can be classified as breaded. Batter containing oxidized starch resulted in the lowest absorption oil and the highest hardness, which may be associated with the amylose content. The use of modified bean, an unconventional botanical source of starch, proved to be possible due their technological properties and the results of breaded products. / O feijão apresenta alto consumo no Brasil, sendo muito consumido em complemento com o arroz. Trata-se de um alimento nutritivo, rico em carboidratos, que representa 60% da massa seca dos grãos, sendo o amido a maior fração. O amido é um polímero natural de glucose e é considerado como a reserva energética dos vegetais superiores. Este biopolímero apresenta-se como grânulos semicristalinos, sendo uma mistura de moléculas de amilose e amilopectina, essa em maior concentração. Na sua forma nativa, o amido possui aplicação limitada, especialmente como agente ligante, em função de baixa resistência térmica e elevada tendência à retrogradação. Por isso, modificações, biológicas, físicas e químicas, podem ser utilizadas de modo a melhorar as suas propriedades tecnológicas, tornando-o aplicável a nível industrial. O presente trabalho teve como objetivo a extração de amido de feijão, avaliação das propriedades físico-químicas e tecnológicas, modificação por oxidação, acetilação e oxidação seguida de acetilação, além de aplicação em empanados cárneos. Pela análise dos difratogramas de Raios X, o amido de feijão demonstrou padrão do tipo C, típico de leguminosas. As imagens de microscopia eletrônica revelaram que os grânulos apresentaram formato oval e elíptico. A oxidação do amido foi evidenciada pelo aumento nos teores de carbonila e carboxila. As amostras acetiladas apresentaram grau de substituição que permite aplicação em alimentos e a substituição de hidroxilas por grupos acetil foi comprovada por bandas na região de 1735-1740 cm-1. Os amidos modificados exibiram alterações nas suas propriedades tecnológicas. A amostra oxidada apresentou aumento da viscosidade de pico e setback, em função dos grupos carboxílicos. O amido acetilado demonstrou possuir uma estabilidade de cozimento de pasta, por apresentar baixo breakdown. As entalpias de gelatinização das amostras modificadas reduziram, em função do enfraquecimento da estrutura granular, assim como a cristalinidade relativa, dureza e adesividade dos géis. A aplicação dos amidos de feijão nos empanados cárneos apresentou resultados interessantes. O sistema com amido oxidado resultou na maior adesão, com 72% da crosta coberta após a fritura. Os empanados apresentaram rendimento superior a 100%, o que indica ganho de massa durante as etapas de empanamento. Os pick-ups das amostras com amido foram inferiores a 30%, o que faz com que os produtos possam ser classificados como breadered. O batter contendo amido oxidado, resultou na menor absorção e óleo e maior dureza, o que pode estar associado ao teor de amilose. O uso de amido de feijão modificado, uma fonte botânica não-convencional, mostrou-se possível, dada as suas propriedades tecnológicas e resultados da aplicação em empanados.

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