• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 5
  • 2
  • 1
  • 1
  • Tagged with
  • 15
  • 15
  • 5
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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

Grain Bag Storage Systems: Monitoring, Analysis, and Effects

Ward, Jason Kellam 12 May 2012 (has links)
Grain production in the Mid-South US has exceeded traditional grain bin storage capacity in recent years. Alternative grain storage methods were adopted. One method was grain bag storage. This system has been used for silage and high moisture corn storage for decades and has been employed for dry grain in other regions of the world, but little research was available to describe the internal environment of the grain bags and its effects on grain quality. Weather conditions, agricultural methods, and cultural practices vary; therefore further research was required to assess this storage practice and describe best management practices for the local region. The objectives of this study were to develop a system and method to monitor the grain bag internal environment, to determine the internal environment and quality of dried grains stored in grain bags, and to determine the internal environment and quality of harvest moisture and condition corn stored in grain bags. An instrumentation system of thermocouples and relative humidity sensors was successfully developed. Fourier analysis was applied and sampling interval less than 10 hours was required to fully describe the grain bag environment. Commercially conditioned (dried and blended) corn (14.1 % MCwb) and soybeans (10.4 %MCwb) were stored in grain bags for 20 and 16 weeks, respectively. Corn immediately after harvest (17.1 %MCwb) was stored for 12 weeks. There were significant differences between grain in the center of the bag and peripheral temperature, with the periphery closely tracking ambient conditions. Psychrometric calculations (humidity ratio and dew-point) indicated that moisture migrated to the bag edges. Temperature within the grain mass never fell below the temperature required for condensation, condensation at the bag internal surface was likely. Grab samples did not reflect significant differences in grain moisture content across the bag profile. Geostatistical methods were used to interpolate the thermal environment of the grain bags; ordinary kriging was the best method of interpolation. Commercially conditioned corn maintained its quality while in storage, while soybeans lost one US grade. Harvest condition corn deteriorated in quality to US Sample grade while in storage. Short storage periods for early harvest corn are recommended.
2

The impact of platelet storage time on transfusion results

Robertsson, Axel January 2010 (has links)
Platelets are small fragments, but they are of crucial importance for the coagulation. The risk of spontaneous bleeding increases when the level of platelets falls below a thrombocyte particle concentration threshold value of 50 x 109/L. In those cases a platelet transfusion might be compulsory. Ongoing research tries to improve the quality of the platelets and to increase the safety of the method used. However, we still need to better understand which factors that affect how patients react upon platelet transfusion. In this study, 100 transfusions performed at Uppsala University Hospital during 2009 were examined. The platelets used had been produced with apheresis followed by pathogen inactivation by Intercept Blood SystemTM. Platelets were counted before and after transfusions and the increase was calculated in purpose to examine how well the patients responded to the platelet transfusions. These values were plotted against platelet storage time in order to examine the possible impact on the result of treatment.
3

Effects on product quality for probiotic yoghurts caused by long storage times during production

Larsson, Catrine January 2009 (has links)
<p>Recent years there has been a large increase in the worldwide sales of cultured products containing probiotics. The obstacle in the production of fermented products incubated with probiotic strains is its effect on sensory, chemical and physical properties. This Master´s Thesis investigates how extended storage times in fermentation tank as well as buffer tank during production of probiotic yoghurts affect final product quality. Through experimental studies, maximum storage times for probiotic yoghurts were to be recommended. The study includes analyses of pH, viscosity, stability, acetic acid concentration, microbial viability and sensory evaluations.</p><p>Design of experiments (DOE) was used to construct a 3<sup>2</sup>-factorial design for the experiment where different storage times were tested. The analyses showed that:</p><ul><li>pH decreases with both storage time in fermentation tank and buffer tank.</li><li>Viscosity increases with long storage times in fermentation tank, while it decreases with long storage times in buffer tanks.</li><li>Many samples had a sandy/grainy and slimy texture which could be related to high levels of Bifidobacteria or high fermentation temperatures.</li><li>High levels of acetic acid was found in all samples.</li><li>All measurements data where within the specification limits, whereas no recommendation for maximum storage times during production could be given.</li></ul>
4

Essays on spatial point processes and bioinformatics

Fahlén, Jessica January 2010 (has links)
This thesis consists of two separate parts. The first part consists of one paper and considers problems concerning spatial point processes and the second part includes three papers in the field of bioinformatics. The first part of the thesis is based on a forestry problem of estimating the number of trees in a region by using the information in an aerial photo, showing the area covered by the trees. The positions of the trees are assumed to follow either a binomial point process or a hard-core Strauss process. Furthermore, discs of equal size are used to represent the tree-crowns. We provide formulas for the expectation and the variance of the relative vacancy for both processes. The formulas are approximate for the hard-core Strauss process. Simulations indicate that the approximations are accurate.  The second part of this thesis focuses on pre-processing of microarray data. The microarray technology can be used to measure the expression of thousands of genes simultaneously in a single experiment. The technique is used to identify genes that are differentially expressed between two populations, e.g. diseased versus healthy individuals. This information can be used in several different ways, for example as diagnostic tools and in drug discovery. The microarray technique involves a number of complex experimental steps, where each step introduces variability in the data. Pre-processing aims to reduce this variation and is a crucial part of the data analysis. Paper II gives a review over several pre-processing methods. Spike-in data are used to describe how the different methods affect the sensitivity and bias of the experi­ment. An important step in pre-processing is dye-normalization. This normalization aims to re­move the systematic differences due to the use of different dyes for coloring the samples. In Paper III a novel dye-normalization, the MC-normalization, is proposed. The idea behind this normaliza­tion is to let the channels’ individual intensities determine the cor­rection, rather than the aver­age intensity which is the case for the commonly used MA-normali­zation. Spike-in data showed that  the MC-normalization reduced the bias for the differentially expressed genes compared to the MA-normalization. The standard method for preserving patient samples for diagnostic purposes is fixation in formalin followed by embedding in paraffin (FFPE). In Paper IV we used tongue-cancer micro­RNA-microarray data to study the effect of FFPE-storage. We suggest that the microRNAs are not equally affected by the storage time and propose a novel procedure to remove this bias. The procedure improves the ability of the analysis to detect differentially expressed microRNAs.
5

Effects on product quality for probiotic yoghurts caused by long storage times during production

Larsson, Catrine January 2009 (has links)
Recent years there has been a large increase in the worldwide sales of cultured products containing probiotics. The obstacle in the production of fermented products incubated with probiotic strains is its effect on sensory, chemical and physical properties. This Master´s Thesis investigates how extended storage times in fermentation tank as well as buffer tank during production of probiotic yoghurts affect final product quality. Through experimental studies, maximum storage times for probiotic yoghurts were to be recommended. The study includes analyses of pH, viscosity, stability, acetic acid concentration, microbial viability and sensory evaluations. Design of experiments (DOE) was used to construct a 32-factorial design for the experiment where different storage times were tested. The analyses showed that: pH decreases with both storage time in fermentation tank and buffer tank. Viscosity increases with long storage times in fermentation tank, while it decreases with long storage times in buffer tanks. Many samples had a sandy/grainy and slimy texture which could be related to high levels of Bifidobacteria or high fermentation temperatures. High levels of acetic acid was found in all samples. All measurements data where within the specification limits, whereas no recommendation for maximum storage times during production could be given.
6

FATE OF MICRO-ORGANIC POLLUTANTS ON THE RECOVERY OF PHOSPHORUS FROM URINE / 尿からリンを回収するプロセスにおける微量汚染物質の挙動解明

PATIYA KEMACHEEVAKUL 26 September 2011 (has links)
Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第16386号 / 工博第3467号 / 新制||工||1524(附属図書館) / 29017 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 清水 芳久, 教授 田中 宏明, 教授 藤井 滋穂 / 学位規則第4条第1項該当
7

Avaliação da microdureza Knoop e do grau de conversão de dois cimentos de ionômero de vidro modificados por resina em função do tipo de polimerização e do tempo / Evaluation of the Knoop microhardness and the degree of conversion of two resin-modified glass ionomer in function of the type of polymerization and the time

Martins, Leandro de Moura 21 May 2007 (has links)
Os ionômeros de vidro vêm sendo utilizados largamente na odontologia com diversas funções. Suas formulações sofreram alterações durante os anos, como a incorporação de componentes resinosos, para a melhoria de suas propriedades físicas e aumento do tempo de trabalho. Com isso, o estudo teve como objetivo avaliar o grau de conversão e a microdureza Knoop dos cimentos de ionômero de vidro modificados por resina (Rely X Luting e Vitremer, ambos da 3M ESPE) de acordo a forma de polimerização (química ou fotopolimerável por lâmpada halógena Ultralux EL ? Gnatus e LED LEC 1000 ? MMOptics) e o tempo de armazenagem. Três espécimes de cada material, autopolimerizável e fotopolimerizável, e tipo de fotopolimerização (por luz halógena e LED) foram confeccionados para cada tempo experimental de 6 horas, 1, 2, 3, 5, 7 ,11 e 14 dias (n=72). Os espécimes foram armazenados em ambiente escuro a 37°C durante esses períodos. Os 72 espécimes foram analisados pela espectroscopia FT-IR para a medição do grau de conversão (GC). Três espécimes de cada material e tipo de polimerização (n=9) foram confeccionados para a medição da microdureza, com um penetrador diamantado piramidal, tipo Knoop, carga estática de 50 gramas por 30 segundos. Os resultados encontrados demonstraram que o material fotopolimerizado com LED apresentou os maiores valores do grau de conversão e da microdureza. O grau de conversão aumentou com o tempo de armazenagem enquanto a microdureza obteve os maiores resultados entre 24-48 horas. Os resultados permitiram concluir que para os cimentos de ionômero de vidro modificados por resina, Vitremer e Rely X Luting, o material fotopolimerizável onde se utilizou o LED apresentou os melhores resultados e que a microdureza Knoop foi ineficaz para predizer o grau de conversão. / Glass ionomer cement have been widely used for many functions. Over the years, some alterations have been made to improve some physico-mechanical properties and to prolong working time. The purpose of this study was to evaluate the relation of the degree of conversion (DC) and Knoop microhardness of resin modified glass ionomer cements (Rely X Luting and Vitremer - 3M ESPE) with polymerization type (chemical curing and light curing reactions, using halogen light or LED) and time of storage. Three specimens of each material, self-cured and light-cured, and light-curing type (halogen light or LED) were prepared for each period of time (n=72). Specimens were stored in dark and dry conditions, at 37oC, during 6 hours, 1, 2, 3, 5, 7, 11 and 14 days. All the specimens were analyzed by FT-IR spectroscopy to measure the DC. Three specimens of each material and polimeryzation type (n=9) were prepared for the microhardness determination, equipped with a Knoop indenter, 50g load for 30 seconds. Results showed that higher values of DC and Knoop microhardness were found on the LED light-cured material. DC values increased with storage time while the Knoop microhardness achieved its higher values between 24-48 hours. Results showed that the LED light-curing unit used to polymerize the resin modified glass ionomer cement Vitremer achieved better values of DC, between light and self-cured materials, and that the Knoop microhardness could not predict the DC.
8

Impacto do transporte a granel na qualidade microbiológica e físico-química e na composição do leite cru refrigerado em indústria de laticínios. / Impact of bulk transport in microbiological, physical-chemical quality and composition of raw cooled milk in dairy industry

Felipus, Nadine Cristina 21 March 2017 (has links)
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-03-16T12:55:23Z No. of bitstreams: 1 PGCA17MA215.pdf: 1647507 bytes, checksum: 1c4f64e83500f380a07f262ae5ae2919 (MD5) / Made available in DSpace on 2018-03-16T12:55:23Z (GMT). No. of bitstreams: 1 PGCA17MA215.pdf: 1647507 bytes, checksum: 1c4f64e83500f380a07f262ae5ae2919 (MD5) Previous issue date: 2017-03-21 / Milk is nutritionally complete, but a highly perishable food and its characteristics easily altered by the action of microorganisms and by the manipulation to which it is submitted. The quality and shelf life of the product that reaches the consumer is directly related to the raw material received for industrialization, and consequently to the conditions and practices carried out in obtaining, storing and transporting. The objective of this study was to evaluate the influence of transport of raw milk on the count of psychrotrophic microrganisms, total bacterial count, physical-chemical and compositional analyses of the refrigerated raw milk received in a dairy industry of Vale do Itajaí – SC, Brazil. Other objective of this study was to evaluate the use of the preservative azidiol ®, under controlled conditions and under field conditions, in the count of psychrotrophic microorganisms and in the total bacterial count of refrigerated raw milk. Two experiments were carried out. In the first one, samples were collected, with and without the use of the preservative azidiol®, in bulk tanks of 3 dairy farms, which were stored under laboratory refrigeration (7ºC) and analyzed at pre-defined times (0, 6, 12 and 24 hours). In the second experiment, samples were collected with and without the use of the azidiol® preservative in the raw milk capture at routes of a dairy (in the storage tanks of the farms, in the isothermal compartments of the trucks and in the storage silo of the industry), doing analysis at varying times. Data were analyzed by ANOVA, regression analysis, means comparison and multivariate factorial analysis. Samples collected without preservatives showed increasing psychrotrophic microrganisms counts and total bacterial count as the time between collection and analysis increased. In the samples conserved by azidiol ®, psychrotrophic microrganisms counts and total bacterial count remained constant during the time between collection and analysis. The transport of raw milk in bulk worsened the microbiological quality of the milk, but did not show influence on the compositional and physical-chemical results of the milk received in the industry. Poor hygiene conditions in storage rooms and in expansion tanks influenced the increase of psychrotrophic microrganisms counts and total bacterial count. This increase was also related to farms with lower production, but with less representative influence. It was observed a relation of milk transport in bulk in cleaner trucks with lower counts of psychrotrophic microorganisms. The transport route time and temperature increase during the transport increased counts of total bacteria and psychrotrophic bacteria, with more pronounced effect for total bacterial count / O leite é um alimento nutricionalmente completo, porém altamente perecível, tendo suas características facilmente alteradas pela ação de microrganismos e pela manipulação a que é submetido. A qualidade e tempo de prateleira do produto que chega ao consumidor estão diretamente relacionados à matéria-prima recebida para industrialização e, consequentemente, às condições e práticas realizadas na obtenção, armazenamento e seu transporte. Este estudo teve como objetivo a avaliação da influência do transporte do leite cru a granel sobre a contagem de microrganismos psicrotróficos, contagem bacteriana total, análises físico-químicas e composição do leite cru refrigerado recebido em uma indústria de laticínios da Região do Vale do Itajaí – SC. Também objetivou avaliar o uso do conservante azidiol®, em condições controladas e em condições a campo, na contagem de microrganismos psicrotróficos e na contagem bacteriana total de leite cru refrigerado. Foram realizados dois experimentos. No primeiro, foram coletadas amostras, com e sem o uso do conservante azidiol®, em tanques de expansão de três propriedades rurais, as quais foram armazenadas em laboratório e sob refrigeração (7ºC) e analisadas em tempos pré-definidos (0, 6, 12 e 24 horas). No segundo experimento foram coletadas amostras com e sem a adição do agente bacteriostático azidiol® em rotas de captação de matéria-prima de um laticínio (nos tanques de armazenamento das propriedades rurais, nos compartimentos isotérmicos dos caminhões e no silo de armazenamento da indústria), analisando-as em tempos variáveis. Os dados foram avaliados por análise de variância e de regressão, comparação de médias e pela técnica de análise multivariada fatorial. Amostras coletadas sem conservante demonstraram contagem de microrganismos psicrotróficos e CBT crescentes à medida que o tempo entre a coleta e a análise aumentava. Já nas amostras adicionadas do conservante azidiol® a contagem de microrganismos psicrotróficos e a CBT se mantiveram constantes durante o tempo entre a coleta e a análise. O transporte do leite cru a granel piorou a qualidade microbiológica do leite; porém, não demonstrou influência nos resultados das análises composicionais e físico-químicas do leite recebido na indústria. Condições ruins de higiene nas salas de armazenamento e nos tanques expansão influenciaram o aumento da contagem de microrganismos psicrotróficos e a CBT. Este aumento também foi relacionado com propriedades com menor produção de leite, porém, com influência menos representativa. Observou-se relação do transporte do leite a granel em caminhões mais limpos com menores contagens de microrganismos psicrotróficos. Maior tempo da rota de transporte e o aumento da temperatura do leite durante o transporte aumentaram as contagens de bactérias totais e de microrganismos psicrotróficos, sendo este efeito mais pronunciado para a CBT
9

Avaliação da microdureza Knoop e do grau de conversão de dois cimentos de ionômero de vidro modificados por resina em função do tipo de polimerização e do tempo / Evaluation of the Knoop microhardness and the degree of conversion of two resin-modified glass ionomer in function of the type of polymerization and the time

Leandro de Moura Martins 21 May 2007 (has links)
Os ionômeros de vidro vêm sendo utilizados largamente na odontologia com diversas funções. Suas formulações sofreram alterações durante os anos, como a incorporação de componentes resinosos, para a melhoria de suas propriedades físicas e aumento do tempo de trabalho. Com isso, o estudo teve como objetivo avaliar o grau de conversão e a microdureza Knoop dos cimentos de ionômero de vidro modificados por resina (Rely X Luting e Vitremer, ambos da 3M ESPE) de acordo a forma de polimerização (química ou fotopolimerável por lâmpada halógena Ultralux EL ? Gnatus e LED LEC 1000 ? MMOptics) e o tempo de armazenagem. Três espécimes de cada material, autopolimerizável e fotopolimerizável, e tipo de fotopolimerização (por luz halógena e LED) foram confeccionados para cada tempo experimental de 6 horas, 1, 2, 3, 5, 7 ,11 e 14 dias (n=72). Os espécimes foram armazenados em ambiente escuro a 37°C durante esses períodos. Os 72 espécimes foram analisados pela espectroscopia FT-IR para a medição do grau de conversão (GC). Três espécimes de cada material e tipo de polimerização (n=9) foram confeccionados para a medição da microdureza, com um penetrador diamantado piramidal, tipo Knoop, carga estática de 50 gramas por 30 segundos. Os resultados encontrados demonstraram que o material fotopolimerizado com LED apresentou os maiores valores do grau de conversão e da microdureza. O grau de conversão aumentou com o tempo de armazenagem enquanto a microdureza obteve os maiores resultados entre 24-48 horas. Os resultados permitiram concluir que para os cimentos de ionômero de vidro modificados por resina, Vitremer e Rely X Luting, o material fotopolimerizável onde se utilizou o LED apresentou os melhores resultados e que a microdureza Knoop foi ineficaz para predizer o grau de conversão. / Glass ionomer cement have been widely used for many functions. Over the years, some alterations have been made to improve some physico-mechanical properties and to prolong working time. The purpose of this study was to evaluate the relation of the degree of conversion (DC) and Knoop microhardness of resin modified glass ionomer cements (Rely X Luting and Vitremer - 3M ESPE) with polymerization type (chemical curing and light curing reactions, using halogen light or LED) and time of storage. Three specimens of each material, self-cured and light-cured, and light-curing type (halogen light or LED) were prepared for each period of time (n=72). Specimens were stored in dark and dry conditions, at 37oC, during 6 hours, 1, 2, 3, 5, 7, 11 and 14 days. All the specimens were analyzed by FT-IR spectroscopy to measure the DC. Three specimens of each material and polimeryzation type (n=9) were prepared for the microhardness determination, equipped with a Knoop indenter, 50g load for 30 seconds. Results showed that higher values of DC and Knoop microhardness were found on the LED light-cured material. DC values increased with storage time while the Knoop microhardness achieved its higher values between 24-48 hours. Results showed that the LED light-curing unit used to polymerize the resin modified glass ionomer cement Vitremer achieved better values of DC, between light and self-cured materials, and that the Knoop microhardness could not predict the DC.
10

Off-gassing from thermally treated lignocellulosic biomass

Borén, Eleonora January 2017 (has links)
Off-gassing of hazardous compounds is, together with self-heating and dust explosions, the main safety hazards within large-scale biomass storage and handling. Formation of CO, CO2, and VOCs with concurrent O2 depletion can occur to hazardous levels in enclosed stored forest products. Several incidents of CO poisoning and suffocation of oxygen depletion have resulted in fatalities and injuries during cargo vessel discharge of forest products and in conjunction with wood pellet storage rooms and silos. Technologies for torrefaction and steam explosion for thermal treatment of biomass are under development and approaching commercialization, but their off-gassing behavior is essentially unknown. The overall objective of this thesis was to provide answers to one main question: “What is the off-gassing behaviour of thermally treated lignocellulosic biomass during storage?”. This was achieved by experimental studies and detailed analysis of off-gassing compounds sampled under realistic conditions, with special emphasis on the VOCs. Presented results show that off-gassing behavior is influenced by numerous factors, in the following ways. CO, CO2 and CH4 off-gassing levels from torrefied and stream-exploded biomass and pellets, and accompanying O2 depletion, are comparable to or lower than corresponding from untreated biomass. The treatments also cause major compositional shifts in VOCs; emissions of terpenes and native aldehydes decline, but levels of volatile cell wall degradation products (notably furans and aromatics) increase. The severity of the thermal treatment is also important; increases in torrefaction severity increase CO off-gassing from torrefied pine to levels comparable to emissions from conventional pellets, and increase O2 depletion for both torrefied chips and pellets. Both treatment temperature and duration also influence degradation rates and VOC composition. The product cooling technique is influential too; water spraying in addition to heat exchange increased CO2 and VOCs off-gassing from torrefied pine chips, as well as O2 depletion. Moreover, the composition of emitted gases co-varied with pellets’ moisture content; pellets of more severely treated material retained less moisture, regardless of their pre-conditioning moisture content. However, no co-variance was found between off-gassing and pelletization settings, the resulting pellet quality, or storage time of torrefied chips before pelletization. Pelletization of steam-exploded bark increased subsequent VOC off-gassing, and induced compositional shifts relative to emissions from unpelletized steam-exploded material. In addition, CO, CO2 and CH4 off-gassing, and O2 depletion, were positively correlated with the storage temperature of torrefied softwood. Similarly, CO and CH4 emissions from steam-exploded softwood increased with increases in storage temperature, and VOC off-gassing from both torrefied and steam-exploded softwood was more affected by storage temperature than by treatment severity. Levels of CO, CO2 and CH4 increased, while levels of O2 and most VOCs decreased, during storage of both torrefied and steam-exploded softwood.CO, CO2 and O2 levels were more affected by storage time than by treatment severity. Levels of VOCs were not significantly decreased or altered by nitrogen purging of storage spaces of steam-exploded or torrefied softwood, or controlled headspace gas exchange (intermittent ventilation) during storage of steam-exploded bark. In conclusion, rates of off-gassing of CO and CO2 from thermally treated biomass, and associated O2 depletion, are comparable to or lower than corresponding rates for untreated biomass. Thermal treatment induces shifts in both concentrations and profiles of VOCs. It is believed that the knowledge and insights gained provide refined foundations for future research and safe implementation of thermally treated fuels as energy carriers in renewable energy process chains.

Page generated in 0.122 seconds