In bread-making, the baking process is one of the key steps to produce the final product quality attributes including texture, color and flavor, as a result of several thermal reactions such as non-enzymatic browning reaction, starch gelatinisation and protein denaturation. These thermal reactions are dominated by heat and mass transfer mechanisms inside an oven chamber as well as inside the dough pieces. In this study, an industrial baking process was divided into 4 zones. Experiments were conducted, and mathematical models were developed to account for the heat and mass contribution as well as their consequent impacts on the product qualities. Monitoring systems were developed and installed inside an industrial oven to evaluate oven performance, including temperature profile and airflow pattern. Many other tests and experiments were conducted and results given in some detail. To deal with the complexity of a continuous baking process, a three dimensional transient-state CFD model with moving grids was established to account for the effect of oven load on heat transfer in the oven chamber. The dynamic response of the travelling tin temperature profiles could be predicted in accordance with a change in the oven load. The modelled tin temperature profiles showed a good agreement with the measured tin temperature profiles from the actual industrial baking process. Finally, the three-dimensional CFD model could provide guidance in manipulating the oven condition to achieve the optimum temperature profile in the industrial travelling-tray baking oven. / Doctor of Philosophy (PhD)

Large-scale bread bakeries generally exist as ‘Islands of Control’ - a long line of processes interrelated, but not interconnected in terms of their control systems. To successfully implement a control system that encompasses the entire bakery, much information must be gathered and processed in such a form that process and control engineers can deduce control algorithms. This project involved the instrumentation of an entire bakery with a view to providing production reports that merge the processes. New methods of tracking products through the entire process were investigated and tested. Methods were also proposed and tested to log temperature/humidities of various bakery processes and align with products passing through to produce a loaf/time/temperature profile.

Current research has developed a fully predictive model of an electrically heated common residential oven. This system was modeled using a fully explicit approach and, where applicable, considered natural convective correlations, various radiation networks, and conduction relations. Two oven configurations were modeled, a conventional (unmodified) residential oven and a modified design. By comparing the theoretical results obtained through modeling with experimental results, verification of the modeling assumptions and results has been achieved. This research has produced an analytical design tool for predictive modeling of time dependant surface temperatures, maximum expected temperatures, and the baking performance of various oven designs. Thus this software package can be used to predict the overall feasibility of an oven design prior to fabrication.

No description available.

The thesis work is a part of a project where the major goal is to improve the efficiency of the evaluations of microwave ovens at Whirlpool Sweden AB. The purpose of the work has been to develop an automatic control and measurement system for microwave ovens. In an earlier thesis work, a test rig has been developed and this test rig has been further developed to an autonomous system. The software for this system is developed in LabVIEW and interfaces to some measuring instruments has been implemented for the system. As a plan for the programming work, UML-diagrams were created in Visual Paradigm To make it easy for the user to handle the system, a user interface has been created in LabVIEW. The system handles different XML-files: oven profiles and test profiles, which are defined by the user. An oven profile contains coordinates for specific positions at the front of a microwave oven, e.g. button positions and corners. There will be one oven profile per oven model. A test profile contains different stages with position names, operations and time delays. The position names are the names of the positions defined in the oven profile. The results from a measurement will be saved in a CSV-file.

Despite the extensive research carried out on waste of electrical and electronic equipment (WEEE) over the past decades, little is known about the quality of electronic products discarded and the extent to which quality affects the decisions to dispose and reuse these products as well as the impact of the current design of products for reuse and remanufacture. This information is fundamental to understand the reasons for the recent unfettered growth in electronic waste, and to propose solutions to address this problem. In this thesis, using a multi-method approach, face to face semi-structured interviews and product fault find surveys, the author investigates and reports the reasons consumers dispose of microwave ovens and the quality of the products, in particular microwave ovens, that are discarded in the United Kingdom as well as recommended design changes to original equipment manufacturers in order to facilitate reuse and increase the lifespan of such products. By collecting and testing 189 microwave ovens disposed of cosmetic imperfections, as well as electrical and mechanical defects, the results revealed that: (i) a fifth of all microwaves disposed are in perfect working condition and can be reused without any reuse process, (ii) a high percentage of the microwaves discarded have only very minor defects, (iii) almost all microwaves discarded with minor defects can be safely refurbished for re-use, (iv) very few components are responsible for most mechanical and electrical faults, (v) for most microwaves disposed of, the prices of the parts necessary for repair are a very small fraction of the average price of a new microwave. Using face to face interviews with 82 persons disposing electronic microwaves it was also found that: (i) consumers are largely unaware of alternative routes to send their end-of-life/use functional products other than the public recycling facilities, and (ii) a large proportion of the consumers disposing of microwaves intend to buy a similar product, only partially supporting the widely-held belief that e-waste is driven by a desire for the latest technology. Based on these results, the author argues that, for microwave ovens disposed in the United Kingdom via household waste recycling centres, the quality of the products discarded is not a serious impediment for reuse, neither are the prices of spare parts. Furthermore, the major factor preventing reuse is the current design of this product, which makes remanufacturing difficult and onerous, as well as the receptiveness of the market for second hand items. Using this information, the author also proposes small changes in design that can significantly improve reusability and, as a consequence, increases the life span of these products.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-06-29T11:48:02Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação de Mestrado - Lívia Rodrigues e Brito.pdf: 11880513 bytes, checksum: cdf56fe284940b9c31e62271753b913f (MD5) / Made available in DSpace on 2016-06-29T11:48:02Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação de Mestrado - Lívia Rodrigues e Brito.pdf: 11880513 bytes, checksum: cdf56fe284940b9c31e62271753b913f (MD5) Previous issue date: 2014-08-25 / CNPq / A adição de aditivos detergentes dispersantes nas gasolinas brasileiras será obrigatória a partir de julho de 2015. É necessário, portanto, desenvolver uma metodologia que permita quantificar esses aditivos para verificar o cumprimento da lei. Neste trabalho, é proposto um método que associa a técnica do ring-oven com as imagens hiperespectrais no infravermelho próximo (NIR-HI). Como os aditivos são adicionados em baixas concentrações, a técnica do ring-oven foi empregada para concentrá-los previamente à análise por NIR-HI. Anéis foram produzidos a partir de amostras de gasolinas comum adicionadas dos aditivos (denominados G, T, W e Y) fornecidos pela Agência Nacional do Petróleo, Gás Natural e Biocombustíveis (ANP) e as imagens adquiridas utilizando uma câmera hiperespectral (SisuCHEMA). Três estratégias de extração dos espectros do anel foram testadas a fim de se escolher a mais rápida e objetiva. A estratégia escolhida se baseia nos histogramas dos escores da primeira componente principal das imagens analisadas individualmente. Modelos de calibração individuais para cada aditivo foram construídos empregando a regressão por mínimos quadrados parciais (PLS), por isso, fez-se necessária uma etapa prévia de classificação. O melhor resultado para classificação foi obtido empregando a análise discriminante linear (LDA) associada ao algoritmo genético (GA) para seleção de variáveis, o qual apresentou uma taxa de classificações corretas de 92,31 %. Observou-se que a maioria dos erros de classificação envolveram amostras dos aditivos G e W. Um único modelo de regressão para esses dois aditivos foi, então, construído e seu erro foi equivalente aos dos modelos individuais. Os modelos de regressão apresentaram erros médios de predição entre 2 e 15 %. Esses resultados mostram que a metodologia proposta pode ser utilizada para determinar as concentrações dos aditivos com confiabilidade e garantir que eles estão sendo adicionados conforme a lei. / The addition of detergent dispersant additives to Brazilian gasoline will be mandatory from July 2015. It is necessary, therefore, to develop a methodology that allows quantifying these additives to verify their compliance with the law. In this work, a method that associates the ring-oven technique with near infrared hyperspectral images (NIR-HI) is proposed. Because the additives are added in low concentrations, the ring-oven technique was employed to concentrate them prior to the NIR-HI analysis. Rings were produced from samples of gasolines without additives spiked with additives (called G, T, W and Y) provided by the National Agency of Petroleum, Natural Gas and Biofuels (ANP) and the images were acquired using a hyperspectral camera (SisuCHEMA). Three strategies for extraction of the ring spectra were tested in order to select the faster and most objective. The chosen strategy is based on the histograms of the first principal component scores of the images analyzed individually. Regression models were built for each additive using partial least squares (PLS) regression, so it was necessary to have a previous classification stage. The best classification result was obtained using the linear discriminant analysis (LDA) associated with the genetic algorithm (GA) for variable selection, which showed a correct classification rate of 92.31 %. It was observed that most of the misclassification errors involved the samples of the G and W additives. A single regression model was then built for these two additives and its error was equivalent to the errors of the individual models. The regression models showed average prediction errors between 2 and 15 %. These results show that the proposed methodology can be used to determine the additive concentrations with reliability and to ensure that they are been added according to the law.

Orientador: Celio Pasquini / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-26T13:37:44Z (GMT). No. of bitstreams: 1 FariasFilho_BeneditoBatista_D.pdf: 5266552 bytes, checksum: 237a6af16ec6a610644e50129eb718d9 (MD5) Previous issue date: 2014 / Resumo: A determinação direta de amostras líquidas utilizando a técnica de Espectroscopia de Emissão Óptica em Plasma Induzido por Laser (LIBS) é muito difícil devido aos limites de detecção insuficientes obtido. Procedimentos de pré-concentração, como o ring oven, permitem que o analito seja determinado a partir de técnicas que utilizam a microanálise como o LIBS, depois da sua transferência para um substrato sólido (papel de filtro). Embora esta abordagem tenha sido praticamente descrita na literatura, o procedimento de medida foi feito manualmente. Assim, neste trabalho foi desenvolvido um sistema de medida mecanizado para analisar por LIBS o conteúdo do anel produzido pela técnica ring oven visando melhorar a precisão e reduzir o tempo de análise. O sistema é composto por um motor contínuo que gira uma plataforma a 10 rpm constituída por um disco de teflon® adaptado ao seu eixo central e que serve como suporte para amostra. A câmara de ICCD do sistema de detecção do LIBS foi programada para integrar o sinal produzido por 120 pulsos do laser que são disparados espaçados uniformemente sobre o contorno do anel durante 6 segundos. Para preparo dos anéis, 60 µL das soluções ou amostras de cachaça eram dispensadas sobre o papel de filtro com vazão de 25 µL min-1 e, em seguida, lavadas com 45 µL de HCl 0,05 mol L-1. Foi utilizado lítio (2 mg L-1; 670,80 nm) como padrão interno para construção das curvas analíticas na faixa de 0 a 8 mg L-1 de cobre (324,75 nm). O padrão interno foi efetivo para corrigir as falhas de amostragem ao longo do contorno do anel durante o processo de medida. As curvas analíticas construídas foram lineares (r > 0,990) na faixa de concentração estudada e o limite de detecção e de quantificação foram de 0,3 mg L-1 e 1,0 mg L-1, respectivamente. Os resultados da determinação de cobre em oito amostras de cachaça mostraram-se estatisticamente indistinguíveis, em nível de 95% de confiança, quando comparados com aqueles obtidos por meio do método oficial de adição de padrão e medidos por espectrometria de absorção atômica em chama (FAAS), com precisão média relativa de 9%. O procedimento de pré-concentração necessitou menos que seis minutos enquanto que as medidas do anel formado, usando o sistema mecanizado, necessitaram no total de dois minutos adicionais. Além disso, foi verificada a potencialidade da técnica ring oven/LIBS para classificação geográfica, por meio de modelos multivariados quimiométricos (LDA, PLS-DA e SIMCA) de cachaças da região de Salinas (MG). A capacidade preditiva das amostras foi melhor para o modelo quimiométrico baseado em Análise Discriminante Linear (LDA), conseguindo classificar corretamente 70% das amostras / Abstract: Direct determination of liquid samples using the technique of Laser-induced breakdown spectroscopy (LIBS) is very difficult due to the insufficient detections limits attained. Procedures of preconcentration, such the ring oven, allow the determination of analyte by microanalysis techniques, after transferring it to a solid substrate (filter paper). Although this approach has been previously described in the literature, the measurement procedure was performed manually. Thus, in this work a mechanized measurement system was developed to analyze by LIBS the contents of the ring produced through the ring oven technique in order to improve the precision and reduce the analysis time. The system consists of a continuous motor that spinning a platform at 10 rpm constituted by a teflon® disc coupled to its axis, serving as a support for the sample. The ICCD camera of the detection system of LIBS was programmed to integrate the signal generated by 120 laser pulses that is fired uniformly spaced on the ring contour during 6 seconds. To prepare the rings, 60 µL of standard solutions or samples of cachaça were dispensed on the filter paper at flow rate of 25 uL min-1 and afterwards washed with 45 µL of HCl 0.05 mol L-1 (42% v/v ethanol). Lithium (2 mg L-1, 670.80 nm) was used as internal standard for the construction of analytical curves in the range from 0 to 8 mg L-1 of copper (324.75 nm). The internal standard was effective to correct the sampling failures around the contour of the ring during the measurement process. Analytical calibration curves were linear (r> 0.99) in the concentration range studied and the limits of detection and quantification were of 0.3 mg L-1 and 1.0 mg L-1, respectively. The results of determination of copper in eight samples of cachaça showed be statistically indistinguishable, at 95% confidence level when compared with the official method of standard addition and measurement by flame atomic absorption spectroscopy (FAAS), with an average relative precision of 9%. The procedure carry out of preconcentration requires less than six minutes, while the measurements of the formed ring, using the mechanized system, requires an total two minutes to be performed. Moreover, it was verified the potentiality of ring oven/LIBS technique for geographic classification of cachaça of Salinas region (Minas Gerais State) using chemometric multivariate modeling (LDA, SIMCA and PLS-DA). The better predictive performace was attained by the chemometric model basead Linear Discriminant Analysis (LDA), achieving correctly classification of 70% of the samples / Doutorado / Quimica Analitica / Doutor em Ciências

Master of Science / Department of Animal Sciences and Industry / Micheal J. Brouk / Two studies were conducted that focused on either the accuracy of hand-held near infrared spectrophotometer (NIR) units and two on-farm testing methods compared to conventional 105°C oven drying of corn silage or the use of a starling resistant supplement in total mixed rations (TMR) for lactating dairy cattle. Study 1 evaluated the accuracy of three NIR units (Digi-Star Moisture Tracker, Topcon Agriculture, Fort Atkinson, WI), food dehydrator (FD) (Nesco®, Two Rivers, WI), and a Koster Tester (KT) (Koster Moisture Tester, Inc., Brunswick, OH) to conventional 105°C forced air oven drying. Samples were taken at four Kansas dairy farms and analyzed for DM daily for 20 d. Two calibrations were tested within each NIR unit: NIRu was the DM predicted from the factory-preset calibration, and NIRc was a bias-adjusted DM prediction based on the average difference of oven-dried corn silage and NIRu over the 20-d study. Average oven DM of corn silage was 38.38% ± 0.59 for the 20-d experiment. All three NIRu measurements were lower (P<0.05) than the oven value. While all 3 NIRc predictions were similar (P>0.05) to oven value. KT value was similar (P>0.05) to the oven, while FD value was over estimated DM. (P<0.05). The hand-held NIRS units accurately predicted DM content of the corn silages when the factory preset calibrations were corrected for bias. While the food dehydrator over-estimated the DM of the corn silage and the Koster Tester accurately predicted DM. Study 2 was designed to evaluate the lactation performance of post-peak dairy cattle when using a starling resistant grain supplement. Sixteen prim- and multiparous Holstein cows were housed individually in a tie-stall barn, milked 3x daily, and fed 2x daily. Cows were fed two nutritionally similar diets: 1. TMR with grain in mash form and 2. TMR with grain supplement in a pellet with a 0.953-cm diameter. This study was designed as a single reversal experiment with two 14 d periods with the first 7 d used for an adaptation period and the last 7 d used for data collection in each period. Dry matter intake (DMI), water intake, and milk production was recorded daily. Feed ingredients, TMRS, refusals, and milk samples were collected the last 3 d of each period for analysis. TMRs and refusals were analyzed for particle size distribution with a Penn State Particle Separator. The pelleted supplement had a higher (P<0.05) percentage of DM retained on the 8.0-19.0mm sieve than the mash supplement as the pellet diameter was >8.0mm and could not pass through that sieve. There was no effect of diet (P>0.05) for DMI, feed efficiency, milk component percentage, and protein yield. There was a diet effect (P<0.05) for milk production, fat-corrected milk, energy-corrected milk, solid-corrected milk, and fat yield with lower observed values when cows were fed the pelleted supplement. This leads to the conclusion while a 0.953-cm diameter pellet will reduce starling consumption, it may result in lower milk production of post-peak Holstein cows.

A presente pesquisa objetivou estudar a remoção dos poluentes presentes em uma água residuária de coqueria, através do processo biológico de nitritação/desnitritação operando um reator de lodo ativado em bateladas seqüenciais em duas etapas sucessivas. Durante a primeira, o reator foi alimentado com um efluente sintético composto por dois poluentes abundantes em despejos de coqueria: nitrogênio amoniacal (500 mg N/L) e fenol (1.000 mg C6H5OH/L). Na segunda, o reator foi alimentado com o despejo gerado na unidade de coqueria de uma indústria siderúrgica integrada. Ao longo da primeira etapa, ao final da fase aeróbia dos 28 ciclos de tratamento, foi possível alcançar eficiências de remoção de N-NH3 superiores a 90% com predominância do N-NO2 - na massa líquida do reator evidenciado pelas relações N-NO2 -/ (N-NO2 - + N-NO3 -) superiores a 86%. O principal mecanismo de inibição das bactérias oxidantes de nitrito (BON) foram concentrações de amônia livre no conteúdo do reator entre 3,2 e 19,5 mg NH3/L. As taxas específicas de nitritação variaram entre 0,03 e 0,11 kg N-NH3/ kg SSV.dia, para temperaturas no conteúdo do reator entre 15 e 34°C. Durante a fase anóxica, o fenol mostrou-se adequado como fonte de carbono para a biomassa desnitritante, desde que as taxas de aplicação volumétricas fossem inferiores a 0,02 kg fenol/m³.hora. Respeitando essa condição, foi possível alcançar: eficiências de remoção de fenol entre 45 e 56%; taxas específicas de remoção de fenol entre 0,03 e 0,09 kg C6H5OH / kg SSV.dia; taxas específicas de desnitritação entre 0,03 e 0,06 kg N-NO2 -/ kg SSV.dia e eficiências de remoção de (N-NO2 - + N-NO3 -) superiores a 95%. Ao longo da fase anóxica foram retiradas amostras do conteúdo do reator para a realização de análises de nitrofenóis (NF). Os resultados acusaram a presença de 2 nitrofenol e 4 nitrofenol em concentrações proporcionais à taxa de aplicação volumétrica do fenol na massa líquida do reator. A presença desses compostos em concentrações inferiores a 0,5 mg/L não causou impacto sobre a desnitritação biológica. As análises realizadas em amostras coletadas ao final da reação anóxica, não acusaram a presença de 2 e 4 NF, demonstrando que esses compostos podem ser biodegradados por uma biomassa bem adaptada ao fenol. A concepção do sistema para tratamento da água residuária de coqueria via nitritação/desnitritação envolveu a operação de dois reatores (principal e reator de polimento) operados em bateladas seqüenciais. As condições de operação do reator principal eram manipuladas para viabilizar o acúmulo de NNO2 - ao final da fase aeróbia e promover a desnitritação durante a fase anóxica, utilizando como fonte de carbono a própria matéria orgânica presente no despejo. Como o sobrenadante do reator principal apresentava concentrações elevadas de N-NO2 -, esse efluente era aplicado no reator de polimento, juntamente com etanol como fonte de carbono para redução do NNO2 -. Ao final da fase aeróbia dos ciclos de tratamento conduzidos no reator principal alcançaram-se: relações NO2 -/ (N-NO2 - + N-NO3 -) superiores a 88%; eficiências de remoções de nitrogênio total superiores a 60%; remoções de N-NH3 superiores a 90%, para valores de pH na massa líquida do reator entre 7,8 e 8,5 e, temperatura entre 23 e 31°C. Tal qual ocorrido durante a primeira etapa da investigação, o principal mecanismo de inibição da atividade das bactérias oxidantes de nitrito foi a toxicidade conferida pelas concentrações de amônia livre (3,7 a 15,7 mg NH3/L) no conteúdo do reator. Durante a fase anóxica, as eficiências de remoção de (N-NO2 - foram limitadas pela disponibilidade de matéria orgânica biodegradável no despejo da coqueria, razões DBO/DQOafluente superiores a 80% resultaram em remoções de N-NO2 - próximas de 100%. Quanto ao reator de polimento, pode-se afirmar que o etanol teve um efeito positivo sobre a remoção de matéria orgânica da água residuária da coqueria, considerando a configuração (dois lodos) utilizada. / The present research aimed to study the coke-oven wastewater treatment over nitritation/denitritation in an activated sludge sequencing batch reactor in two successive phases. During the first one, the reactor was fed with a synthetic effluent composed by two abundant pollutants present in coke-oven wastewaters: total ammonia nitrogen (500 mg TAN.l-1) and phenol (1,000 mg C6H5OH.l-1). During the second phase, the reactor was fed with the wastewater produced in an integrated steel industrys coke-plant. The results of the first phase (28 cycles) showed that was possible to achieve TAN removal efficiencies higher than 90% with NO2 --N predominance in the reactor content, evidenced by the rates NO2 --N/ (NO2 --N + NO3 --N) higher than 86%. The main mechanism of the nitrite oxidizer bacteria (NOB) inhibition was free ammonia concentrations between 3.2 and 19.5 mg NH3.l-1. The specific nitritation rates varied between 0.03 and 0.11 kg TAN. kg VSS-1.d-1, for temperatures between 15 and 34oC. Phenol showed to be suitable as carbon source for denitrifying biomass, once the volumetric application rates were lower than 0.02 kg phenol.m-3.h-1. Obeying this condition, it was possible to achieve: phenol removal efficiencies between 45 and 56%; specific phenol removal rates between 0.03 and 0.09 kg C6H5OH. kg VSS-1.d-1; specific denitritation rates between 0.03 and 0.06 kg NO2 --N . kg VSS-1.d-1 and removal efficiencies of (NO2 --N + NO3 --N) higher than 95%. During the anoxic phase, samples were collected from the reactor content for nitrophenols analyses. The results showed the presence of 2- nitrophenol (2-NP) and 4-nitrophenol (4-NP) in concentrations proportional to phenol volumetric application rate in the reactor liquid mass. The presence of those compounds in concentrations lower than 0.5 mg/L does not cause impact over the biological denitritation. The analyses accomplished in samples collected at the end of the anoxic reaction do not show the presence of 2 and 4-NP, demonstrating that these compounds can be biodegraded by a well-adapted biomass. The arrangement of the system for the treatment of coke-oven wastewater (Phase 02) over nitritation/denitritation involved the operation of two sequencing batch reactors (the main reactor and the polishing one). The operational conditions of the main reactor were manipulated to make feasible the NO2 --N accumulation at the end of the aerobic stage and promote the denitritation using the own organic matter present in the cokeoven wastewater as carbon source. As the supernatant of the main reactor presented high nitrite concentrations, this effluent was conducted to a biological denitrifying polishing reactor with ethanol as carbon source. At the end of the aerobic stage of the treatment cycles conducted in the main reactor, it was achieved: NO2 --N/ (NO2 --N + NO3 --N) higher than 88%; total nitrogen removal efficiencies higher than 60%; ammonia nitrogen removal higher than 90%. As occurred during the first phase of the investigation, the main NOB activity inhibition was the toxicity of the free ammonia concentrations (3.7 to 15.7 mg NH3.l-1) in the reactor content. At the end of anoxic stage, the NO2 --N removal efficiencies were limited by the availability of the biodegradable organic matter in the coke-oven wastewater but BOD/CODinfluent higher than 80% resulted in NO2 --N removals next to 100%. Regarding to the polishing reactor, it can be stated that the ethanol had a positive effect over the organic matter removal of the coke-oven wastewater.