The objective of this study was to investigate the effects of preheat treatments on fouling by fresh whole milk (FWM), recombined whole milk (RCB) and reconstituted whole milk (Recon) in the high-temperature heater of indirect UHT plants. Various preheat treatments prior to evaporation during milk powder manufacture were applied to skim milk powder (SMP, 75 °C 2 s, 85 °C, 155 s and 95 °C, 155 s) and whole milk powder (WMP, 95 °C, 33 s). These preheat treatments were so-called “evaporator preheat treatments”. Skim milk powder (SMP) and whole milk powder (WMP) were derived from the same original batch of pasteurised FWM to remove the effects of the variation in milk composition between different milk batches. These SMPs were recombined with anhydrous milk fat and water to prepare RCB, and WMPs were reconstituted with water to prepare Recon. Then, (homogenized) FWM, RCB and Recon were subjected to various preheat treatments (75 °C, 11 s, 85 °C, 147 s and 95 °C, 147 s) prior to UHT processing. These preheat treatments were so-called “UHT preheat treatments”. Temperature difference (hot water inlet temperature – milk outlet temperature) was taken as a measure of the extent of fouling in the high-temperature heater. The slope of the linear regression of temperature difference versus time (for two hours of UHT processing) was taken as fouling rate (°C/h). Increasing both evaporator and UHT preheat treatments resulted in increasing fouling rate and total deposit weight for all three whole milk types for several milk batches. In the case of FWM, there was no reduction in fouling rate with increasing UHT preheat treatment whether FWM was homogenized then preheated, preheated then homogenized or not homogenized at all. These findings, which are wholly consistent and well replicated, are in apparent conflict with the results of most previous comparable studies. Possible reasons for this are explained. Further investigations of the effects of homogenization relating to the role of whey protein on the surface of the fat globules showed that whey protein associated with the membrane covering the surface of fat globules for homogenized then preheated FWM, RCB and Recon and that association increased with increasing heating process stage. The increasing association of whey protein with the milk fat globules membrane with increasing severity of heating process stage became faster when preheat treatment was more severe: the association of whey protein plateaued on intermediate temperature heating when the milks were preheated at 75°C, 11 s and on preheating when the milks were preheated at 95°C, 147 s. In the case of FWM, the thickness of the membrane covering the surface of fat globules for homogenized then preheated FWM, which increased with the severity of heating process stage, was greater than the thickness of the membrane in preheated then homogenized FWM. Preheating then homogenization resulted in the greater interfacial spreading of small molecules on the surface of fat globules, i.e. whey protein or small molecules from the disintegration of casein micelles during preheating. Possible basic mechanisms for UHT fouling in the high-temperature heater include: the reduction in the solubility of calcium phosphate and the deposition of protein as fat-bound protein and non-fat-bound protein. When non-fat-bound protein in milk plasma deposited, it could be a carrier for the deposition of mineral, such as, the precipitate of calcium phosphate in the casein micelles or the deposition of complexes between whey protein and casein micelles.

The objective of this study was to investigate the effects of preheat treatments on fouling by fresh whole milk (FWM), recombined whole milk (RCB) and reconstituted whole milk (Recon) in the high-temperature heater of indirect UHT plants. Various preheat treatments prior to evaporation during milk powder manufacture were applied to skim milk powder (SMP, 75 °C 2 s, 85 °C, 155 s and 95 °C, 155 s) and whole milk powder (WMP, 95 °C, 33 s). These preheat treatments were so-called “evaporator preheat treatments”. Skim milk powder (SMP) and whole milk powder (WMP) were derived from the same original batch of pasteurised FWM to remove the effects of the variation in milk composition between different milk batches. These SMPs were recombined with anhydrous milk fat and water to prepare RCB, and WMPs were reconstituted with water to prepare Recon. Then, (homogenized) FWM, RCB and Recon were subjected to various preheat treatments (75 °C, 11 s, 85 °C, 147 s and 95 °C, 147 s) prior to UHT processing. These preheat treatments were so-called “UHT preheat treatments”. Temperature difference (hot water inlet temperature – milk outlet temperature) was taken as a measure of the extent of fouling in the high-temperature heater. The slope of the linear regression of temperature difference versus time (for two hours of UHT processing) was taken as fouling rate (°C/h). Increasing both evaporator and UHT preheat treatments resulted in increasing fouling rate and total deposit weight for all three whole milk types for several milk batches. In the case of FWM, there was no reduction in fouling rate with increasing UHT preheat treatment whether FWM was homogenized then preheated, preheated then homogenized or not homogenized at all. These findings, which are wholly consistent and well replicated, are in apparent conflict with the results of most previous comparable studies. Possible reasons for this are explained. Further investigations of the effects of homogenization relating to the role of whey protein on the surface of the fat globules showed that whey protein associated with the membrane covering the surface of fat globules for homogenized then preheated FWM, RCB and Recon and that association increased with increasing heating process stage. The increasing association of whey protein with the milk fat globules membrane with increasing severity of heating process stage became faster when preheat treatment was more severe: the association of whey protein plateaued on intermediate temperature heating when the milks were preheated at 75°C, 11 s and on preheating when the milks were preheated at 95°C, 147 s. In the case of FWM, the thickness of the membrane covering the surface of fat globules for homogenized then preheated FWM, which increased with the severity of heating process stage, was greater than the thickness of the membrane in preheated then homogenized FWM. Preheating then homogenization resulted in the greater interfacial spreading of small molecules on the surface of fat globules, i.e. whey protein or small molecules from the disintegration of casein micelles during preheating. Possible basic mechanisms for UHT fouling in the high-temperature heater include: the reduction in the solubility of calcium phosphate and the deposition of protein as fat-bound protein and non-fat-bound protein. When non-fat-bound protein in milk plasma deposited, it could be a carrier for the deposition of mineral, such as, the precipitate of calcium phosphate in the casein micelles or the deposition of complexes between whey protein and casein micelles.

The objective of this study was to investigate the effects of preheat treatments on fouling by fresh whole milk (FWM), recombined whole milk (RCB) and reconstituted whole milk (Recon) in the high-temperature heater of indirect UHT plants. Various preheat treatments prior to evaporation during milk powder manufacture were applied to skim milk powder (SMP, 75 °C 2 s, 85 °C, 155 s and 95 °C, 155 s) and whole milk powder (WMP, 95 °C, 33 s). These preheat treatments were so-called “evaporator preheat treatments”. Skim milk powder (SMP) and whole milk powder (WMP) were derived from the same original batch of pasteurised FWM to remove the effects of the variation in milk composition between different milk batches. These SMPs were recombined with anhydrous milk fat and water to prepare RCB, and WMPs were reconstituted with water to prepare Recon. Then, (homogenized) FWM, RCB and Recon were subjected to various preheat treatments (75 °C, 11 s, 85 °C, 147 s and 95 °C, 147 s) prior to UHT processing. These preheat treatments were so-called “UHT preheat treatments”. Temperature difference (hot water inlet temperature – milk outlet temperature) was taken as a measure of the extent of fouling in the high-temperature heater. The slope of the linear regression of temperature difference versus time (for two hours of UHT processing) was taken as fouling rate (°C/h). Increasing both evaporator and UHT preheat treatments resulted in increasing fouling rate and total deposit weight for all three whole milk types for several milk batches. In the case of FWM, there was no reduction in fouling rate with increasing UHT preheat treatment whether FWM was homogenized then preheated, preheated then homogenized or not homogenized at all. These findings, which are wholly consistent and well replicated, are in apparent conflict with the results of most previous comparable studies. Possible reasons for this are explained. Further investigations of the effects of homogenization relating to the role of whey protein on the surface of the fat globules showed that whey protein associated with the membrane covering the surface of fat globules for homogenized then preheated FWM, RCB and Recon and that association increased with increasing heating process stage. The increasing association of whey protein with the milk fat globules membrane with increasing severity of heating process stage became faster when preheat treatment was more severe: the association of whey protein plateaued on intermediate temperature heating when the milks were preheated at 75°C, 11 s and on preheating when the milks were preheated at 95°C, 147 s. In the case of FWM, the thickness of the membrane covering the surface of fat globules for homogenized then preheated FWM, which increased with the severity of heating process stage, was greater than the thickness of the membrane in preheated then homogenized FWM. Preheating then homogenization resulted in the greater interfacial spreading of small molecules on the surface of fat globules, i.e. whey protein or small molecules from the disintegration of casein micelles during preheating. Possible basic mechanisms for UHT fouling in the high-temperature heater include: the reduction in the solubility of calcium phosphate and the deposition of protein as fat-bound protein and non-fat-bound protein. When non-fat-bound protein in milk plasma deposited, it could be a carrier for the deposition of mineral, such as, the precipitate of calcium phosphate in the casein micelles or the deposition of complexes between whey protein and casein micelles.

Health claims for barley β-glucan (BG) have prompted the development of more food products using barley. Some new products do not use any form of heat treatment which could become an issue as barley has been found to have high microbial contamination. The aim of this research was to evaluate current commercial barley products for microbial and BG quality and determine the effects of different heat treatments on the safety and physicochemical properties of BG of whole grain barley. Three heat treatments (micronization, roasting and conditioning) were performed on 3 cultivars of barley (CDC Rattan, CDC McGwire and CDC Fibar). The microbial quality was measured with standard plate count (SPC), yeast and mould (MYC), and coliforms/E. coli. Only 4 of the 17 commercial barley products tested met acceptable microbial limits used in this study. All 3 heat treatments reduced SPC, MYC and coliforms to acceptable levels. BG was extracted using an in vitro digestion method to determine its viscosity, molecular weight (MW) and solubility. Heat-treated barley increased the BG viscosity and MW compared to the untreated barley. The effect of heat treatment on starch pasting, particle size and colour were also evaluated. Overall, heat treatments improved the safety and potential health benefits of whole grain barley. / February 2016

Made available in DSpace on 2014-12-17T14:07:09Z (GMT). No. of bitstreams: 1 JoseFTJ_TESE.pdf: 4834280 bytes, checksum: 1a618560296186081bd6c34117d226be (MD5) Previous issue date: 2012-07-04 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Thin commercial aluminum electrolytic and passed through reactions was obtained with anodic alumina membranes nanopores. These materials have applications in areas recognized electronic, biomedical, chemical and biological weapons, especially in obtaining nanostructures using these membranes as a substrate or template for processing nanowires, nanodots and nanofibers for applications noble. Previous studies showed that the membranes that have undergone heat treatment temperature to 1300? C underwent changes in morphology, crystal structure and optical properties. This aim, this thesis, a study of the heat treatment of porous anodic alumina membranes, in order to obtain and to characterize the behavior changes structures during the crystallization process of the membranes, at temperatures ranging between 300 and 1700? C. It was therefore necessary to mount a system formed by a tubular furnace resistive alumina tube and controlled environment, applying flux with special blend of Ag-87% and 13% N2, in which argon had the role of carrying out the oxygen nitrogen system and induce the closing of the pores during the densification of the membrane. The duration of heat treatment ranged from 60 to 15 minutes, at temperatures from 300 to 1700? C respectively. With the heat treatment occurred: a drastic reduction of porosity, grain growth and increased translucency of the membrane. For the characterization of the membranes were analyzed properties: Physical - thermogravimetric, X-ray diffraction, BET surface area; morphological - SEM, EDS through compositional and, optical absorbance, and transmittance in the UV-VIS, and FTIR. The results using the SEM showed that crystallization has occurred, densification and significant changes in membrane structure, as well as obtaining microtube, the BET analysis showed a decrease in specific surface area of the membranes has to 44.381 m2.g-1 to less than 1.8 m2.g-1 and in the analysis of transmittance and absorbance was found a value of 16.5% in the range of 800 nm, characteristic of the near infrared and FTIR have confirmed the molecular groups of the material. Thus, one can say that the membranes were mixed characteristics and properties which qualify for use in gas filtration system, as well as applications in the range of optical wavelength of the infra-red, and as a substrate of nanomaterials. This requires the continuation and deepening of additional study / L?minas delgadas de alum?nio comercial passaram por rea??es eletrol?ticas e obtiveram-se membranas de alumina an?dica com nanoporos. Estes materiais t?m reconhecidas aplica??es nas ?reas eletr?nicas, biom?dicas, qu?micas e biol?gicas, principalmente, na obten??o de nanoestruturas utilizando estas membranas como substrato ou molde para processamento de nanofios, nanopontos e nanofibras para aplica??es nobres. Estudos anteriores apontaram que as membranas que passaram por tratamentos t?rmicos at? a temperatura de 1300? C, sofreram altera??es na morfologia, na estrutura cristalina e nas propriedades ?pticas. O objetivo deste trabalho foi o estudo do tratamento t?rmico de membranas de alumina an?dica porosas, com o intuito de obter e caracterizar as altera??es de comportamento das estruturas, durante o processo de cristaliza??o das membranas, em temperaturas que variaram entre 300 e 1700? C. Assim, foi necess?rio montar um sistema formado por um forno resistivo tubular e tubo de alumina com ambiente controlado, aplicando fluxo com mistura especial de Ar-87% e N2-13%, no qual o arg?nio teve o papel de carrear o oxig?nio para fora do sistema e o nitrog?nio de induzir o fechamento dos poros, durante a densifica??o das membranas. A dura??o dos tratamentos t?rmicos variou de 60 a 15 minutos, para as temperaturas de 300 at? 1700? C respectivamente. Com o tratamento t?rmico ocorreu redu??o dr?stica da porosidade, crescimento do gr?o e aumento da translucidez da membrana. Para a caracteriza??o das membranas, foram feitas an?lises das propriedades: f?sica - termogravim?trica; difra??o de raios-X, ?rea superficial BET; morfol?gica - MEV, composicional atrav?s do EDS; e, ?ptica - transmit?ncia e absorb?ncia no UV-VIS e FTIR. Os resultados por meio do MEV mostraram que ocorreu cristaliza??o, densifica??o e mudan?as significativas na estrutura das membranas, bem como, a obten??o de microtubo; a an?lise de BET constatou uma diminui??o na ?rea superficial espec?fica das membranas que passou de 44,381m2.g-1, para menos de 1,8m2.g-1; na an?lise de transmit?ncia e absorb?ncia foi encontrado um valor de 16,5 % na faixa de 800nm, caracter?stico do infravermelho pr?ximo e no FTIR foram confirmadas os grupos moleculares do material. Assim, pode-se afirmar que as membranas apresentaram caracter?sticas mistas e propriedades que as qualificam para o uso em sistema de filtra??o de gases, bem como, de aplica??es ?ticas na faixa do comprimento de onda do Infravermelho, e como substrato de nanomateriais. Isto requer a continuidade e aprofundamento em estudos complementares

Made available in DSpace on 2014-10-09T12:46:42Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:09Z (GMT). No. of bitstreams: 1 07613.pdf: 5555459 bytes, checksum: 0047c9f052248797761d648268e841ba (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:44:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:39Z (GMT). No. of bitstreams: 1 06912.pdf: 10380955 bytes, checksum: 3e22ae9dda613db66c72f121ed37b278 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-06-29T14:16:18Z No. of bitstreams: 1 ISIS TATIANE DE BARROS MACÊDO VELOSO - TESE (PPGCEMat) 2016.pdf: 3573054 bytes, checksum: bfcbdc962777a12887f4d94980048582 (MD5) / Made available in DSpace on 2018-06-29T14:16:18Z (GMT). No. of bitstreams: 1 ISIS TATIANE DE BARROS MACÊDO VELOSO - TESE (PPGCEMat) 2016.pdf: 3573054 bytes, checksum: bfcbdc962777a12887f4d94980048582 (MD5) Previous issue date: 2016-06-30 / A reciclagem de vidros surge como alternativa ao impacto causado pelo seu descarte no meio ambiente, contribuindo para preservação dos recursos naturais, redução na emissão de gases e diminuição no volume dos aterros e lixões. O vidro pode ser infinitamente reciclado, sem que haja perda de massa ou de suas propriedades. Além disso, destaca-se pela sua beleza, por ser um dos poucos materiais capazes de refletir luz, cuja aplicação pode resultar em produtos de elevado apelo estético. Esta pesquisa tem como objetivo o desenvolvimento de pastilhas para revestimento pelo processo de reciclagem de resíduos de vidros sódico-cálcicos, a partir de estudos de tratamento térmico de fusão e recozimento. Inicialmente, os vidros foram separados por cor, triturados manualmente, distinguidos em diferentes granulometrias e acondicionados em moldes de concreto celular. Em seguida, foram submetidos a diferentes tratamentos térmicos, que resultaram na fusão e recozimento, este último processo para minimizar as tensões internas que fragilizam o vidro. Desta forma, buscou-se analisar a influência das granulometrias e dos tratamentos térmicos sobre os aspectos visuais das peças; os estudos dos materiais dos moldes e sua interação com o vidro, a desmoldabilidade e o acabamento das pastilhas; os equipamentos utilizados para a cominuição dos cacos de vidro. Como resultados, definiu-se o tratamento térmico quatro (TT4) para os vidros incolores e o tratamento térmico cinco (TT5) para os vidros coloridos (azul, âmbar, verde claro e verde escuro), em busca de obter peças de textura enrugada, aspecto vítreo e superfície brilhosa. Quanto ao tratamento térmico, as análises realizadas por microscopia óptica mostraram a eliminação das tensões internas que fragilizam o vidro, assim como o teste de impacto demonstrou uma maior resistência ao choque para amostras com recozimento, comprovando, assim, sua eficácia. Quanto à viabilidade de produção, os resultados demonstraram que as pastilhas são passíveis de serem confeccionadas pelo grupo CAVI, em escala artesanal, utilizando tecnologias e recursos acessíveis ao grupo, numa perspectiva de tecnologia social. / Glass recycling is an alternative to the impact caused by its disposal in environment, contributing to preservation of natural resources, reduction in gas emissions and decrease in volume of landfills and dumps. Glass can be recycled endlessly without any loss of mass or its properties. In addition, stands out for its beauty, for being one of few materials capable of reflecting light, the implementation of which may result in high aesthetic appeal products. This research aims to develop glass pastilles for coatings by recycling process of sodium-calcium glass residues, from heat treatment studies of melting and annealing. Initially, glasses were separated by color, manually grinded, distinguished into different granulometries and conditioned in cellular concrete molds. Then were subjected to different heat treatments, which resulted in melting and annealing, the latter process to minimize the internal tensions that weaken glass. Thus, it sought to analyze the influence of grain size and thermal treatments of visual aspects of the pieces; studies of materials of molds and their interaction with glass, demoldability and finish of the tablets; equipment used for comminution of the glass. As a result, it defined the heat treatment four (TT4) for colorless glass and heat treatment five (TT5) for tinted (blue, amber, light green, dark green) in seeking to obtain pieces of wrinkled texture, glassy and glossy surface. About heat treatment, the analysis performed by optical microscopy showed elimination of internal stresses which weaken the glass, and impact test showed a greater shock resistance for samples annealed, confirming thus its effectiveness. As for viability of production, results showed that pastilles are likely to be made by CAVI group, artisanal scale, using technologies and resources accessible to the group, in a perspective of social technology.

[pt] O objetivo principal desta pesquisa foi caracterizar o fenômeno de corrosão localizada na região da junta soldada de elos de amarras do tipo ORQ utilizados em sistemas de ancoragem offshore. Para tal, foram selecionados elos de amarras retirados de serviço ao final de sua vida útil programada e sem sinais de corrosão localizada (elos sem corrosão) e elos de amarras que tiveram abreviada sua vida útil em função de corrosão localizada (elos com corrosão). Inicialmente, promoveu-se a determinação das características microestruturais, na qual se destacou o intenso bandeamento microestrutural de ferrita/perlita, bem como as propriedades mecânicas e de fratura das juntas soldadas em ambas as condições. Em seguida, ensaios eletroquímicos avaliaram a susceptibilidade à corrosão das diferentes regiões da junta soldada. Os resultados mostraram a zona termicamente afetada como anódica, com alta taxa de corrosão em elos com corrosão, enquanto que, em elos sem corrosão, esta mesma região foi catódica, com baixa velocidade de corrosão. Após tais ensaios, a zona termicamente afetada dos elos com corrosão foi submetida a diferentes tratamentos térmicos visando a diminuição de sua taxa de corrosão. O tratamento térmico de recozimento, prévio à têmpera e revenido, foi importante para a diminuição da taxa de corrosão desta região. Finalmente, as juntas soldadas em ambas as condições foram analisadas por difração de raios-X, que evidenciou a presença de partículas de segunda fase contendo níquel e cromo na zona termicamente afetada dos elos com corrosão. Tais partículas foram apontadas, possivelmente, como causadoras do endurecimento e da maior susceptibilidade à corrosão desta região. / [en] The purpose of this work was to characterize the localizated corrosion phenomenom in the weld region of offshore mooring chains type ORQ. In this sense, a number of chain links were selected after finishing their projected life time without corrosion signs (chains without corrosion) as well as chain links which showed a reduced life time caused by localizated corrosion (chains with corrosion). Initially, a microetructural characterization, that revealed a strong ferrite-pearlite banding, as well as mechanical testing were carried out for both material´s conditions. In the sequence, eletrochemistry tests evaluated the corrosion susceptibility of the different regions of the weld joint. The results showed that the heat affected zone concerning the chains with corrosion was the anodic region, with high corrosion rate, while the same region on the not corroded chains was the cathodic one, with low corrosion rate. After that, the heat affected zone regarding the corroded chains was subjected to different heat treatments aiming to reduce its corrosion rate. The annealing heat treatment, previous to quenching and tempering, was considered important in order to decrease the corrosion rate of this region. Finally, the welded joints in both conditions were analyzed by means of X-ray diffraction, which pointed to the presence of second phase particles containing nickel and chromium in the heat affected zone of the corroded chains. The hardening and the high corrosion susceptibility showed by this region was attributed for these particles.

Made available in DSpace on 2014-10-09T12:42:24Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:07Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP