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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

Storage stability of low salt bacon : Microbiological, chemical and sensory aspects

Applegate, J. January 1989 (has links)
No description available.
2

Stability of catfish methyl esters under normal versus accelerated storage conditions

Jongrattananon, Saowalee 13 December 2008 (has links)
Oxidative storage stability was conducted to determine the optimum antioxidant for the production of catfish methyl esters (CFME) for use as biodiesel. Peroxide value, anisidine value, 2-thiobarbituric reaction substances, acid value, iodine value, UV absorbance, and induction period were measured. Antioxidant, stability parameters changed over a storage time of one year when stored at 25°C. The CFME were not stable to oxidation without the addition of TBHQ. When stored at 25°C, oxidative parameters indicated that CFME was a stable product that met oxidative stability standards when TBHQ was added. When held at 80°C for 28 days, the samples with TBHQ were stable to oxidation. However, the acid value rose above the maximum at 28 days. Thus, CFME can be stable to oxidative breakdown when THBQ was added at 800 ppm, but when exposed to high temperatures, one will have to limit water or protect CFME against hydrolytic rancidity.
3

The Rheology, Adhesion, and Stability of Complex Coacervates

Ogundeji, Lamide Isiak January 2021 (has links)
No description available.
4

Impacts of Feedstock Bark Addition and Centrifugal Filtration on Pyrolysis Oil Properties and Storage Stability

Varadarajan, Anandavalli 13 December 2014 (has links)
The physicochemical properties of pyrolysis oil have been shown to be dependent on feedstock composition. Accelerated aging tests were performed to understand the effects of feedstock, condensate fraction collected, and filtration on the stability of pyrolysis oil. In this study, pyrolysis oil properties critical for downstream upgrading were measured and compared for different feedstock weight ratios of pine clearwood and pine bark. Post-condensation filtration of pyrolysis oil was evaluated using both lab-scale and pilot plant-scale centrifugal filtration with several operational parameters evaluated. The pilot-plant centrifuge can be used as a three-phase separator [light liquid-heavy liquid-solids] or a two-phase clarifier [liquid-solid]. Since pyrolysis oil is an oil-water micro-emulsion, separation of the heavy and light liquid phases is difficult; therefore, emulsion destabilization studies were performed in concert with centrifugation. Physicochemical properties were monitored to determine the impact of the production and processing parameters on the oil properties critical to biofuel applications.
5

Obtaining Durable Enzyme Powder Via Spray Drying

Namaldi, Aysegul 01 January 2005 (has links) (PDF)
Serine alkaline protease (SAP, EC 3.4.21.62) produced by Bacillus species, that are the microbioreactors within the bioreactors, is one of the major industrial enzymes. In this study, after production by Recombinant Bacillus subtilis (BGSC-1A751), carrying pHV1431::subc gene in the complex media and separation of solids, SAP was dried by using a spray drier. Experiments were performed to investigate the stabilization of SAP during spray drying and subsequent storage. Initially, the effect of air inlet temperature of the spray drier on SAP activity was evaluated. For this purpose, SAP solutions were spray dried in the absence of any protective agents at five different air inlet temperature (700C, 900C, 1100C, 1200C, 1300C). As a result, increasing air inlet temperature lead to an increase in activity loss of SAP during drying. Thereafter, the effect of protective additives, glucose and maltodextrin (0.5%, 1%, 2% w/v), on SAP activity was investigated during spray drying. The activity loss of SAP was completely inhibited in the presence of glucose at 70, 90 and 1100C. However, the addition of maltodextrin was better than glucose for activity preservation of SAP at 1300C. Among the obtained results, 1% glucose addition was the best to preserve activity of SAP during spray drying. Then, structural change of SAP during drying was investigated. FTIR-ATR spectrum was used to evaluate the change in physical structure of the dried SAP powders in the presence of 1% glucose. From infrared images, at 900C more native-like structure for dried SAP powders was observed. In the last stage of this study storage stability of obtained SAP powders at 40C for a long period (6 months) was investigated. When considering all conditions, 0.5% maltodextrin addition was the best for stabilizing SAP powders along storage time.
6

Monitoramento e controle da contaminação microbiana durante o armazenamento simulado de misturas diesel/biodiesel com uso de biocida / Monitoring and control of microbial contamination during storage of mixtures diesel / biodiesel with use of biocide

Zimmer, Adriane Ramos January 2014 (has links)
Os sistemas de armazenamento de combustível podem apresentar vulnerabilidade á contaminação tanto química quanto microbiana, comprometendo a qualidade final do produto. Este trabalho teve como objetivo selecionar antimicrobianos para utilização no controle da contaminação microbiana de misturas diesel/biodiesel armazenadas e monitorar a degradação química deste combustível. Foram estudados dezoito diferentes produtos antimicrobianos indicados para utilização em combustíveis, quanto ao seu espectro de ação e dosagens contra diferentes grupos microbianos em diferentes tipos de misturas diesel/biodiesel, através de testes em laboratório e em campo. A degradação química da fase oleosa foi monitorada através de testes específicos para algumas características indicativas de qualidade e a análise da degradação microbiana foi acompanhada com espectrometria de infravermelho. Foi realizada a avaliação de um KIT comercial para a detecção de ATP por bioluminescência com a bactéria Pseudomonas e um inóculo não caracterizado ( ASTM1259-10) em fase aquosa (meio mineral e água de drenagem de tanques de estocagem). A toxicidade da fase aquosa que esteve em contato com a mistura B10 e um aditivo selecionado foi avaliada com o uso das espécies Lactuca sativa L. (alface) e Artemia salina Leach (micro-crustáceo), durante 30 dias. Um aditivo contendo 50% de oxazolidina como ativo antimicrobiano em sua formulação foi considerado efetivo para o controle preventivo da contaminação microbiana em misturas B10. Porém outras formulações contendo, isotiazolonas ou morfolinas podem constituir uma boa opção para tratamentos corretivos. O kit para determinação do ATP por bioluminescência testado neste estudo, na forma como está projetado, não é adequado para estimar o grau de contaminação microbiana da fase aquosa proveniente de tanques de combustíveis. Os resultados de toxicidade mostram que tanto a água que esteve em contato com o combustível tratado (com o aditivo) e não tratado apresentaram toxicidade para os organismos estudados. Porém, a água que esteve em contato com o combustível tratado com o biocida mostrou alta toxicidade aguda para ambos os organismos-teste utilizados. / The fuel storage systems may present vulnerability to chemical as well as microbial contamination, compromising final product quality. This goal was to select antimicrobials for use in the control of microbial contamination of diesel/biodiesel blends stored and monitor aspects of chemical degradation of the fuel. 18 different antimicrobial products suitable for use in fuels, as their spectrum of activity against different microbial groups and dosages, in different types of diesel/biodiesel blends by means of laboratory tests and field were studied. The chemical degradation of the oil phase was monitored using specific tests for certain characteristics indicative of quality and analysis of microbial degradation was monitored with infrared spectrometry. The evaluation of a commercial kit for the ATP bioluminescence detection in aqueous phase with Pseudomonas and a uncharacterized inoculum (ASTM1259 -10) (mineral medium and natural bottom water from storage tanks) was performed. The toxicity of aqueous phase which was in contact with the B10 blend and selected additive was evaluated with the use of the species Lactuca sativa L. (Lettuce) and Artemia salina Leach (microcrustacean) for 30 days. An additive containing 50% oxazolidine as antimicrobial agent in its formulation was considered effective for preventive control of microbial mixtures B10. But other formulations containing isothiazolones or morpholines could be a good option for corrective treatment. The kit for determination of ATP bioluminescence tested in this study as designed it’s unappropriate to estimate the degree of microbial contamination of the aqueous phase from the fuel tank. The toxicity results show that both the water that was in contact with the treated fuel (with additive) and untreated showed toxicity to studied organisms. However, the water that was in contact with the biocide treated fuel showed high acute toxicity to both test organisms used.
7

Monitoramento e controle da contaminação microbiana durante o armazenamento simulado de misturas diesel/biodiesel com uso de biocida / Monitoring and control of microbial contamination during storage of mixtures diesel / biodiesel with use of biocide

Zimmer, Adriane Ramos January 2014 (has links)
Os sistemas de armazenamento de combustível podem apresentar vulnerabilidade á contaminação tanto química quanto microbiana, comprometendo a qualidade final do produto. Este trabalho teve como objetivo selecionar antimicrobianos para utilização no controle da contaminação microbiana de misturas diesel/biodiesel armazenadas e monitorar a degradação química deste combustível. Foram estudados dezoito diferentes produtos antimicrobianos indicados para utilização em combustíveis, quanto ao seu espectro de ação e dosagens contra diferentes grupos microbianos em diferentes tipos de misturas diesel/biodiesel, através de testes em laboratório e em campo. A degradação química da fase oleosa foi monitorada através de testes específicos para algumas características indicativas de qualidade e a análise da degradação microbiana foi acompanhada com espectrometria de infravermelho. Foi realizada a avaliação de um KIT comercial para a detecção de ATP por bioluminescência com a bactéria Pseudomonas e um inóculo não caracterizado ( ASTM1259-10) em fase aquosa (meio mineral e água de drenagem de tanques de estocagem). A toxicidade da fase aquosa que esteve em contato com a mistura B10 e um aditivo selecionado foi avaliada com o uso das espécies Lactuca sativa L. (alface) e Artemia salina Leach (micro-crustáceo), durante 30 dias. Um aditivo contendo 50% de oxazolidina como ativo antimicrobiano em sua formulação foi considerado efetivo para o controle preventivo da contaminação microbiana em misturas B10. Porém outras formulações contendo, isotiazolonas ou morfolinas podem constituir uma boa opção para tratamentos corretivos. O kit para determinação do ATP por bioluminescência testado neste estudo, na forma como está projetado, não é adequado para estimar o grau de contaminação microbiana da fase aquosa proveniente de tanques de combustíveis. Os resultados de toxicidade mostram que tanto a água que esteve em contato com o combustível tratado (com o aditivo) e não tratado apresentaram toxicidade para os organismos estudados. Porém, a água que esteve em contato com o combustível tratado com o biocida mostrou alta toxicidade aguda para ambos os organismos-teste utilizados. / The fuel storage systems may present vulnerability to chemical as well as microbial contamination, compromising final product quality. This goal was to select antimicrobials for use in the control of microbial contamination of diesel/biodiesel blends stored and monitor aspects of chemical degradation of the fuel. 18 different antimicrobial products suitable for use in fuels, as their spectrum of activity against different microbial groups and dosages, in different types of diesel/biodiesel blends by means of laboratory tests and field were studied. The chemical degradation of the oil phase was monitored using specific tests for certain characteristics indicative of quality and analysis of microbial degradation was monitored with infrared spectrometry. The evaluation of a commercial kit for the ATP bioluminescence detection in aqueous phase with Pseudomonas and a uncharacterized inoculum (ASTM1259 -10) (mineral medium and natural bottom water from storage tanks) was performed. The toxicity of aqueous phase which was in contact with the B10 blend and selected additive was evaluated with the use of the species Lactuca sativa L. (Lettuce) and Artemia salina Leach (microcrustacean) for 30 days. An additive containing 50% oxazolidine as antimicrobial agent in its formulation was considered effective for preventive control of microbial mixtures B10. But other formulations containing isothiazolones or morpholines could be a good option for corrective treatment. The kit for determination of ATP bioluminescence tested in this study as designed it’s unappropriate to estimate the degree of microbial contamination of the aqueous phase from the fuel tank. The toxicity results show that both the water that was in contact with the treated fuel (with additive) and untreated showed toxicity to studied organisms. However, the water that was in contact with the biocide treated fuel showed high acute toxicity to both test organisms used.
8

Monitoramento e controle da contaminação microbiana durante o armazenamento simulado de misturas diesel/biodiesel com uso de biocida / Monitoring and control of microbial contamination during storage of mixtures diesel / biodiesel with use of biocide

Zimmer, Adriane Ramos January 2014 (has links)
Os sistemas de armazenamento de combustível podem apresentar vulnerabilidade á contaminação tanto química quanto microbiana, comprometendo a qualidade final do produto. Este trabalho teve como objetivo selecionar antimicrobianos para utilização no controle da contaminação microbiana de misturas diesel/biodiesel armazenadas e monitorar a degradação química deste combustível. Foram estudados dezoito diferentes produtos antimicrobianos indicados para utilização em combustíveis, quanto ao seu espectro de ação e dosagens contra diferentes grupos microbianos em diferentes tipos de misturas diesel/biodiesel, através de testes em laboratório e em campo. A degradação química da fase oleosa foi monitorada através de testes específicos para algumas características indicativas de qualidade e a análise da degradação microbiana foi acompanhada com espectrometria de infravermelho. Foi realizada a avaliação de um KIT comercial para a detecção de ATP por bioluminescência com a bactéria Pseudomonas e um inóculo não caracterizado ( ASTM1259-10) em fase aquosa (meio mineral e água de drenagem de tanques de estocagem). A toxicidade da fase aquosa que esteve em contato com a mistura B10 e um aditivo selecionado foi avaliada com o uso das espécies Lactuca sativa L. (alface) e Artemia salina Leach (micro-crustáceo), durante 30 dias. Um aditivo contendo 50% de oxazolidina como ativo antimicrobiano em sua formulação foi considerado efetivo para o controle preventivo da contaminação microbiana em misturas B10. Porém outras formulações contendo, isotiazolonas ou morfolinas podem constituir uma boa opção para tratamentos corretivos. O kit para determinação do ATP por bioluminescência testado neste estudo, na forma como está projetado, não é adequado para estimar o grau de contaminação microbiana da fase aquosa proveniente de tanques de combustíveis. Os resultados de toxicidade mostram que tanto a água que esteve em contato com o combustível tratado (com o aditivo) e não tratado apresentaram toxicidade para os organismos estudados. Porém, a água que esteve em contato com o combustível tratado com o biocida mostrou alta toxicidade aguda para ambos os organismos-teste utilizados. / The fuel storage systems may present vulnerability to chemical as well as microbial contamination, compromising final product quality. This goal was to select antimicrobials for use in the control of microbial contamination of diesel/biodiesel blends stored and monitor aspects of chemical degradation of the fuel. 18 different antimicrobial products suitable for use in fuels, as their spectrum of activity against different microbial groups and dosages, in different types of diesel/biodiesel blends by means of laboratory tests and field were studied. The chemical degradation of the oil phase was monitored using specific tests for certain characteristics indicative of quality and analysis of microbial degradation was monitored with infrared spectrometry. The evaluation of a commercial kit for the ATP bioluminescence detection in aqueous phase with Pseudomonas and a uncharacterized inoculum (ASTM1259 -10) (mineral medium and natural bottom water from storage tanks) was performed. The toxicity of aqueous phase which was in contact with the B10 blend and selected additive was evaluated with the use of the species Lactuca sativa L. (Lettuce) and Artemia salina Leach (microcrustacean) for 30 days. An additive containing 50% oxazolidine as antimicrobial agent in its formulation was considered effective for preventive control of microbial mixtures B10. But other formulations containing isothiazolones or morpholines could be a good option for corrective treatment. The kit for determination of ATP bioluminescence tested in this study as designed it’s unappropriate to estimate the degree of microbial contamination of the aqueous phase from the fuel tank. The toxicity results show that both the water that was in contact with the treated fuel (with additive) and untreated showed toxicity to studied organisms. However, the water that was in contact with the biocide treated fuel showed high acute toxicity to both test organisms used.
9

Effect of the cashew nut shell liquid (CNSL) on the rheological properties of the asphalt binder modified with SBS / Efeito do lÃquido da castanha do caju (LCC) nas propriedades reolÃgicas do ligante asfÃltico modificado por SBS

FabÃola Odete Rodrigues 30 August 2010 (has links)
The objective of this study was to modify the asphalt binder (LA) with 50/70 penetration by incorporating SBS (3, 4 and 4.5%) and the cashew nut shell liquid (CNSL) (1% w/w). The studies were directed towards assessing and analyzing the rheological master curves obtained from tests on a dynamic-shear rheometer (DSR). In addition, we assessed the effects of additives in relation to the viscosity, storage stability, and oxidative aging simulated at the RTFOT. The results indicated that the addition of SBS increases the stiffness and the elastic response of the binder at high temperatures. The master curves showed improvements in the rheological parameters at intermediate and high temperatures, where the process of permanent deformation occurs. Samples with SBS contents 3, 4 and 4.5% were tested for storage stability for 48 hours. The sample with 3% SBS showed no phase separation when stored under the conditions investigated, however, samples with 4 and 4.5% of SBS showed phase separation. In these samples (4 and 4.5%), the addition of CNSL embedded in the modified binder by SBS show the potential to estabilize the binder-polymer mixture, avoiding phase separation. The CNSL, therefore, proved to be potentially useful to prevent phase separation of the LAs with the polymer. The results also indicate that the presence of CNSL promoted a reduction in viscosity and flow activation energy of the binder modified by SBS, contributing thus to improve the thermal susceptibility of the modified binder. Tests of resilient modulus (MR) and tensile strength (RT) in asphalt mixtures containing modified binder suggest that the presence of SBS makes the mixture less susceptible to deformation and failure than mixtures with pure LA. However, the asphalt mixture containing the binder modified by SBS with the addition of CNSL presents an even greater hardening when compared to the SBS blend containing no additive. It is likely that the presence of polymerized CNSL has contributed to the hardening of the sample. / O objetivo deste trabalho foi modificar o ligante asfÃltico (LA) com penetraÃÃo 50/70 pela incorporaÃÃo de SBS (3, 4 e 4,5% m/m) e do lÃquido da castanha do caju (LCC) (1% m/m). Os estudos foram dirigidos para avaliaÃÃo dos parÃmetros reolÃgicos e anÃlise das curvas mestras obtidas atravÃs de ensaios realizados em um reÃmetro de cisalhamento dinÃminco (DSR). AlÃm disso, foram avaliados os efeitos da presenÃa dos aditivos em relaÃÃo à viscosidade, estabilidade à estocagem e envelhecimento oxidativo simulado em estufa RTFOT. Os resultados indicaram que a adiÃÃo de SBS aumenta a rigidez e a resposta elÃstica do ligante em altas temperaturas. As curvas mestras mostraram melhorias nos parÃmetros reolÃgicos em temperaturas intermediÃrias e altas, onde ocorre o processo de deformaÃÃo permanente. As amostras com teores de 3, 4 e 4,5% foram testadas quanto à estabilidade a estocagem por 48h. A amostra com teor de 3% SBS nÃo apresentou separaÃÃo de fases quando estocada nas condiÃÃes trabalhadas, no entanto, as amostras com teores de 4 e 4,5% apresentaram separaÃÃo de fases. Nessas amostras (4 e 4,5%), a adiÃÃo do LCC incorporado ao ligante modificado por SBS demonstrou estabilizar a mistura ligante-polÃmero, evitando a separaÃÃo de fases. O LCC, portanto, mostrou-se potencialmente Ãtil para prevenir a separaÃÃo de fases dos LAs modificados com o polÃmero. Os resultados tambÃm indicam que a presenÃa do LCC promoveu uma reduÃÃo na viscosidade e na energia de ativaÃÃo de fluxo do ligante modificado por SBS, contribuindo, portanto, para melhorar a susceptibilidade tÃrmica do ligante modificado. Os ensaios de mÃdulo de resiliÃncia (MR) e reistÃncia a traÃÃo (RT) nas misturas asfÃlticas contendo os ligantes modificados sugerem que a presenÃa do SBS torna a mistura menos susceptÃvel à deformaÃÃo do que as misturas com o LA puro. No entanto, a mistura asfÃltica contendo o ligante modificado por SBS com adiÃÃo de LCC apresenta um endurecimento ainda maior quando comparada a mistura que contÃm o SBS sem o aditivo. à provÃvel que a presenÃa de LCC polimerizado tenha contribuÃdo para o endurecimento da amostra.
10

Towards a Viscoelastic Model for Phase Separation in Polymer Modified Bitumen

Zhu, Jiqing January 2015 (has links)
In this thesis, a review is given on the most popular polymers used today for polymer modification of bitumen. Furthermore, the development of a model for phase separation in polymer modified bitumen (PMB) is proposed, that will enable a better control and understanding of PMB phase behaviour, allowing thus to enhanced long-term performance. PMB is hereby considered as a blend and focus is placed on its structure, its equilibrium thermodynamics and its phase separation dynamics. The effects of dynamic asymmetry on phase separation in PMB are analysed with related theories and some image data. Based on the discussion in this thesis, it is concluded that the effects of dynamic asymmetry between bitumen and polymer should be taken into consideration when studying phase separation in PMB. By analysing related literature and image data, it is found that some features of viscoelastic phase separation are shown during the phase separation process in some PMBs. It is therefore possible and useful to develop a viscoelastic model for PMB to describe its phase separation behaviour. In this, the stress-diffusion coupling is expected to play a key role in the model. Finally, recommendations are made towards the future research which is needed to realize the proposed model. / <p>QC 20150409</p>

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