This project analyzes the validity of theoretical models used to predict the duration (hold time) for which a halon-replacement suppression agent will remain within a protected enclosure. Two current models and one new formulation are investigated; the sharp descending interface model (as applied in NFPA 2001, Annex C), the wide descending interface model (implemented in ISO 14520.1, Annex E), and the thick descending interface model (introduced herein). The thick interface model develops the characteristic thickness as an additional input parameter. Experimental data from 34 full-scale tests designed to characterize the discharge and draining dynamics of seven clean extinguishing agents (CEA) is used to assess model validity. For purposes of model validation the characteristic thickness is regressed from the experimental data although further work may be required to establish the independence of this parameter to other system design and environmental variables. Results show that the wide and sharp interface models' validity is highly sensitive to the threshold of agent concentration decay being modeled; whereas the thick interface prediction method demonstrates increased robustness at any modeled threshold. When the hold time is defined as a 15% decay in agent concentration, experimentally obtained hold time values are roughly 10% shorter than sharp interface predictions, 60% longer than wide interface predictions, and 30% longer than the thick interface model predicts.

Made available in DSpace on 2017-07-10T19:24:06Z (GMT). No. of bitstreams: 1 Osvaldo Kuczman.pdf: 473345 bytes, checksum: b3778df4351e601c96e945da1cf28c16 (MD5) Previous issue date: 2007-07-18 / The grouping of cassava starch production factories at northwest/west Paraná regions, Mato Grosso do Sul and São Paulo region has led to a million daily income of wastewater, which, treated at stabilization lagoons, generates greenhouse gases, unpleasant odors and landscape s degradation. The current research has evaluated the anaerobic digestion of waste cassava starch in one-phase horizontal reactor, having a 16,2 L volume, operated at 33 ± 1°C with manipueira having organic load rates of 1,28, 1,57, 2,68 and 1,18 g COD L- 1reactor day-1 for the Hydraulic Retention Times (HRT) being the experiment realization order of 12,96, 8,27 6,59 and 15,00 days, respectively. The feeding has been continuous, approaching to the real production s conditions. The cycle evaluation, for each HRT, lasted 15 days, revealing that the time didn t interfere, within 5%. The average removal in Total Solids (TS) is 98 and 77 %, Volatile Solids (VS) 99 and 90%, organic loads 96 and 95%, having as biogas yielding 0,817 and 0,604 L gas g-1 COD removed at the 8, 27 and 6,59 days, respectively. However, the most homogeneous removals in TS and VS occurred at the 12,96 and 8,27 days, not following the COD removals. The best average specific production for biogas ranged from 0,654 to 0,627 L gás L-1r d-1, verified in TRH 8,27 and 6,59 days. The average biogas methane content, come from the 15,00 days HRT, was 58,85%. The average relation Volatile Acidity/Total Alkalinity situated from 0,14 to 0,30. By the obtained results, it was concluded that it is possible to reduce the organic load of waste cassava starch through anaerobic digestion in one-phase horizontal reactor for the conditions established at the present study. / A concentração de indústrias processadoras de mandioca, nas regiões noroeste e oeste do Paraná e sul dos estados de Mato Grosso do Sul e São Paulo, produz diariamente milhões de litros de manipueira diluída que, tratada em lagoas de estabilização, geram gases de efeito estufa, maus odores e impactam a paisagem. Esse estudo avaliou a digestão anaeróbia em reator horizontal de fase única com volume de 16,2 L à temperatura de 33 ± 1 °C, alimentado com manipueira de fecularia e cargas orgânicas de 1,28, 1,57, 2,68, e 1,18 g DQO L-1r d-1 para os tempos de retenção hidráulica (TRH), sendo a ordem de realização dos experimentos de 12,96, 8,27, 6,59 e 15 dias, respectivamente. A alimentação foi contínua, aproximando-se das reais condições de geração de manipueira nas fecularias, sem correção de pH ou nutrientes. O período de avaliação diária, para cada TRH, foi de 15 dias, onde o fator tempo não interferiu ao nível de 5% de significância. As reduções médias de sólidos totais foram de 98 e 77%, sólidos voláteis de 99 e 90%, cargas orgânicas em DQO de 96 e 95% e produções de 0,817 e 0,604 L gás g- 1 DQOc nos TRH s de 8,27 e 65,9 dias, respectivamente. Porém, as reduções mais homogêneas para sólidos totais e voláteis ocorreram nos TRH s de 12,96 e 8,27 dias, não acompanhando a redução de DQO, semelhante apenas no TRH de 12,96 dias. A melhor produção específica média de biogás foi de 0,654, seguida de 0,627 L gás L-1r d-1 verificada no TRH de 8,27 e 6,59 dias e cargas orgânicas médias aplicadas de 1,57 e 2,68 g DQO L-1r d-1, respectivamente. O teor médio de metano no biogás, produzido no TRH de 15 dias, foi de 58,85%. A relação média da acidez volátil versus alcalinidade total, nos TRH s avaliados, permaneceu entre 0,14 e 0,30. A estabilização anaeróbia de manipueira em reator horizontal de fase única mostrou-se eficaz para as condições estabelecidas no presente estudo.

Made available in DSpace on 2017-05-12T14:47:22Z (GMT). No. of bitstreams: 1 Osvaldo Kuczman.pdf: 473345 bytes, checksum: b3778df4351e601c96e945da1cf28c16 (MD5) Previous issue date: 2007-07-18 / The grouping of cassava starch production factories at northwest/west Paraná regions, Mato Grosso do Sul and São Paulo region has led to a million daily income of wastewater, which, treated at stabilization lagoons, generates greenhouse gases, unpleasant odors and landscape s degradation. The current research has evaluated the anaerobic digestion of waste cassava starch in one-phase horizontal reactor, having a 16,2 L volume, operated at 33 ± 1°C with manipueira having organic load rates of 1,28, 1,57, 2,68 and 1,18 g COD L- 1reactor day-1 for the Hydraulic Retention Times (HRT) being the experiment realization order of 12,96, 8,27 6,59 and 15,00 days, respectively. The feeding has been continuous, approaching to the real production s conditions. The cycle evaluation, for each HRT, lasted 15 days, revealing that the time didn t interfere, within 5%. The average removal in Total Solids (TS) is 98 and 77 %, Volatile Solids (VS) 99 and 90%, organic loads 96 and 95%, having as biogas yielding 0,817 and 0,604 L gas g-1 COD removed at the 8, 27 and 6,59 days, respectively. However, the most homogeneous removals in TS and VS occurred at the 12,96 and 8,27 days, not following the COD removals. The best average specific production for biogas ranged from 0,654 to 0,627 L gás L-1r d-1, verified in TRH 8,27 and 6,59 days. The average biogas methane content, come from the 15,00 days HRT, was 58,85%. The average relation Volatile Acidity/Total Alkalinity situated from 0,14 to 0,30. By the obtained results, it was concluded that it is possible to reduce the organic load of waste cassava starch through anaerobic digestion in one-phase horizontal reactor for the conditions established at the present study. / A concentração de indústrias processadoras de mandioca, nas regiões noroeste e oeste do Paraná e sul dos estados de Mato Grosso do Sul e São Paulo, produz diariamente milhões de litros de manipueira diluída que, tratada em lagoas de estabilização, geram gases de efeito estufa, maus odores e impactam a paisagem. Esse estudo avaliou a digestão anaeróbia em reator horizontal de fase única com volume de 16,2 L à temperatura de 33 ± 1 °C, alimentado com manipueira de fecularia e cargas orgânicas de 1,28, 1,57, 2,68, e 1,18 g DQO L-1r d-1 para os tempos de retenção hidráulica (TRH), sendo a ordem de realização dos experimentos de 12,96, 8,27, 6,59 e 15 dias, respectivamente. A alimentação foi contínua, aproximando-se das reais condições de geração de manipueira nas fecularias, sem correção de pH ou nutrientes. O período de avaliação diária, para cada TRH, foi de 15 dias, onde o fator tempo não interferiu ao nível de 5% de significância. As reduções médias de sólidos totais foram de 98 e 77%, sólidos voláteis de 99 e 90%, cargas orgânicas em DQO de 96 e 95% e produções de 0,817 e 0,604 L gás g- 1 DQOc nos TRH s de 8,27 e 65,9 dias, respectivamente. Porém, as reduções mais homogêneas para sólidos totais e voláteis ocorreram nos TRH s de 12,96 e 8,27 dias, não acompanhando a redução de DQO, semelhante apenas no TRH de 12,96 dias. A melhor produção específica média de biogás foi de 0,654, seguida de 0,627 L gás L-1r d-1 verificada no TRH de 8,27 e 6,59 dias e cargas orgânicas médias aplicadas de 1,57 e 2,68 g DQO L-1r d-1, respectivamente. O teor médio de metano no biogás, produzido no TRH de 15 dias, foi de 58,85%. A relação média da acidez volátil versus alcalinidade total, nos TRH s avaliados, permaneceu entre 0,14 e 0,30. A estabilização anaeróbia de manipueira em reator horizontal de fase única mostrou-se eficaz para as condições estabelecidas no presente estudo.

In this thesis, we propose a novel vertical MOSFET device with middle partial insulator (MPI) or VMPI for capacitorless one transistor dynamic random access memory (1T-DRAM) application. In TCAD simulations, we compare the device performances of the planar MPI, conventional silicon-on-insulator SOI, and our proposed VMPI. Based on numerical simulation, we find out that the VMPI device has a large kink phenomenon for improving the programming window. As far as the data retention time is concerned, the hole carriers leaking into the source region are reduced due to the presence of a large pseudo neutral region and an effective blocking oxide layer. The retention time can thus be improved about 5 times when compared with conventional SOI counterpart. Furthermore, it should be noted that the gate-all-around (GAA) VMPI device structure not only increases the body pseudo-neutral region, but also enhances the 1T-DRAM performances, suggesting that the proposed VMPI can become a candidate for 1T-DRAM application.

Wastewater contains many valuable constituents, including phosphorus, nitrogen and more energy than what is required to treat it. This, combined with increasingly more stringent effluent requirements and the desire for water reuse, creates a demand for a system capable of both nutrient and energy recovery. The main objective was to develop a new wastewater treatment process configuration capable of maximizing energy recovery while enhancing biological phosphorus removal. Three pilot membrane bioreactors were operated at SRTs ranging from 2 days to 8 days to evaluate membrane fouling, treatment performance, sludge production and sludge settleability. The results showed high organics removal and near complete nitrification at all SRTs. Membrane fouling was highest at lower SRTs. The collected data were then used to calibrate a series of model configurations. The best configuration consisted of two sludge systems in series, with a short SRT anaerobic-aerobic first stage and an extended SRT pre-anoxic second stage. / Canadian Water Network

At Kungsberget ski-resort in Gävleborg county all wastewater produced at the facility is treated on-site. The treatment takes place at their own wastewater treatment plant in a so-called Sequence Batch Reactor (SBR), which has been in operation for about a year before this study. Kungsberget AB is currently in charge of the facility but their goal is to hand responsibility over to Sandviken Energy AB. In order for this handover to occur Kungsberget has to produce three approved treatment results. This means that the concentrations of BOD7 needs to lie under 0.3 mg/l and total phosphorous under 10 mg/l in the effluent water for three consecutive samples. The results show momentaneous values. These limits are stated in the permit Kungsberget received from the Environmental Protection Division. Kungsberget has had problems with high and fluctuating phosphorous concentrations and therefore the transfer has not yet taken place. In this project several parameters have been analysed in order to obtain an overview of prevailing influent and effluent concentrations. Some of the parameters that have been analysed are; phosphorous, nitrogen, BOD7, suspended solids and pH. A lot of time and effort has been put into elucidating operational routines at the wastewater treatment plant (WWTP) and gaining knowledge from available literature regarding different parameters’ effect on treatment results.   Kungsberget has had problems adapting operating routines and reaching stable treatment results as the load is highly effected of seasonal fluctuation. This has not been taken into account earlier and the WWTP has been operated in the same manner all year around. Suggestions to how operating routines can be modified in to better meeting the needs have been produced and alternative treatment methods have been presented in the report. Two of the suggestions include biological phosphorous removal and adding carrier media to increase bacteria growth. An aerobic solids retention time has been calculated in order to evaluate whether nitrifying bacteria have enough time for grow and maintain a stable population. The calculation was carried out by measuring suspended solids and aeration time and the result was a solids retention time of approximately 6 days.

While forage plays an important role in equine nutrition, little research has been conducted evaluating fiber utilization by young horses. Therefore, studies were conducted to compare in vivo digestibility and digesta passage in weanlings and mature horses (Exp 1) and yearlings and mature horses (Exp 2). All horses were fed forage-based diets at the same rate (on a metabolic BW basis; Exp 1: 67% alfalfa cubes, 33% concentrate; Exp 2: 75% timothy cubes, 25% concentrate). Ytterbium labeled hay and cobalt-ethylenediaminetetraacetic acid were used to estimate digesta mean retention time (MRT), while in vivo digestibility (DM, OM, and NDF) was measured using a total fecal collection method. Feed and water intake was similar between young and mature horses in both experiments. In Exp 1, there were no differences in digestibility or MRT due to age. The results suggested that weanling horses are capable of digesting a relatively high quality diet as efficiently as mature horses and that most of the development of the gastrointestinal tract occurs before 6 mo of age. In Exp 2, digestibility estimates were greater (P < 0.0311) for the yearlings than for the geldings. The increased digestive capacity of the yearlings was likely due to the longer MRT observed for the particulate phase in the yearlings (P = 0.0190). A third study was conducted to compare the microbial profiles of the feces of mares and foals. Fecal samples were collected from mare-foal pairs as the foal matured. The profiles of each pair, obtained using polymerase chain reaction-denaturing gradient gel electrophoresis, were compared and used to describe bacterial colonization in the foal. Mean similarity between mares and their foals on the day of parturition was low, but rapidly increased. Within 2 wk of parturition, similarity among mares and their foals was higher than among mature mares, suggesting that by 2 wk of age the bacterial species found in the foals’ gut are similar to those found in the mature horse. Collectively, the results from this series of experiments describe the early development of the foal’s digestive capacity.

Horses consume large amounts of fiber in their diet, which may affect digestibility and digesta rate of passage. The objective of these studies was to assess the effects of diet composition on digestibility and rate of passage in horses using mathematical models. Using previously published data, forage dry matter digestibility (DMD) was related to forage neutral detergent fiber (NDF) concentrations and crude protein (CP) concentrations (DMD = 66.1178 – 0.3410*NDF + 0.6356*CP, DM basis; P < 0.001). In a second experiment, horses were fed diets formulated to have high fiber (HF, n= 3; NDF = 55.3%, CP = 11.8%) or low fiber (LF, n = 3; NDF = 40.5%, CP = 13.3%) concentrations. The LF treatment had greater DM, organic matter, and gross energy digestibilities (P < 0.05), whereas the HF treatment had greater NDF digestibility (P < 0.05). Mathematical models were useful to determine mean retention time (MRT) and there were no differences between model MRT and algebraic MRT, or treatment. Some compartmental parameters were different between treatments (P < 0.05), indicating that dietary fiber may alter some components of digesta passage in horses.

In gas chromatography, analytes are separated by differences in their partition between a mobile phase and a stationary phase. Temperature-program, column dimensions, stationary and mobile phases, and flow rate are all parameters that can affect the quality of the separation in gas chromatography. To achieve a good separation (in a short amount of time) it is necessary to optimize these parameters. This can often be quite a tedious task. Using computer simulations, it is possible to both gain a better understanding of how the different parameters govern retention and separation of a given set of analytes, and to optimize the parameters within minutes. In the research presented here, this was achieved by taking a thermodynamic approach that used the two parameters ΔH (enthalpy change) and ΔS (entropy change) to predict retention times for gas chromatography. By determining these compound partition parameters, it was possible to predict retention times for analytes in temperature-programmed runs. This was achieved through the measurement of the retention times of n-alkanes, PAHs, alcohols, amines and compounds in the Grob calibration mixture in isothermal runs. The isothermally obtained partition coefficients, together with the column dimensions and specifications, were then used for computer simulation using in-house software. The two-parameter model was found to be both robust and precise and could be a useful tool for the prediction of retention times. It was shown that it is possible to calculate retention times with good precision and accuracy using this model. The relative differences between the predicted and experimental retention times for different compound groups were generally less than 1%. The scientific studies (Papers I-IV) are summarized and discussed in the main text of this thesis. / At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Submitted.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Esta pesquisa tem como objetivo principal equacionar uma variaÃÃo de concentraÃÃo entre o afluente e o efluente em um sistema biofÃsico ou fÃsico-quÃmico. O referencial teÃrico utilizado se embasou em uma equaÃÃo diferencial de escoamento estacionÃrio, envolvendo uma cinÃtica quÃmica e uma dispersÃo longitudinal, em que haja nÃmero de dispersÃo e eficiÃncia suficientemente baixo, relacionadas a reatores. As cinÃticas quÃmicas abordadas foram do tipo Monod, de primeira ordem, de uma ordem qualquer e uma criada semelhante à de tipo Monod. Elaborou-se um novo modelo de decaimento molecular, que propiciou gerar novas equaÃÃes de escoamento estacionÃrio. Obtiveram-se relaÃÃes entre parÃmetros volumÃtricos e uma cinÃtica quÃmica de uma mistura perfeita ou de escoamento estacionÃrio. Neste estudo, foram obtidas algumas similaridades em relaÃÃo à literatura de uma cinÃtica quÃmica em escoamento estacionÃrio. TambÃm foi desenvolvido um estudo visando a permitir melhor dimensionamento do tempo de detenÃÃo hidrÃulico real, razoavelmente comprovado pelas fontes pesquisadas. / The main aim of this research is to evaluate a variation of concentration between the affluent and effluent in a biophysical or physicochemical system. The theoretical system of references used here was based upon a differential equation of steady flow, involving a chemical kinetics and a longitudinal dispersion, in which there is a number of sufficiently low dispersion and efficiency, related to reactors. The chemical kinetics approached was of the Monod type, first order, any order and one which was set up similar to a Monod. We developed a new model of molecular decay which allowed the generation of new equations for steady flow. We obtained relationships between volumetric parameters and chemical kinetics of a perfect mixture of steady flow. In this study we found out about some similarities concerning the literature of chemical kinetics in a steady flow. It was also designed a study aiming to allow better scaling of the actual hydraulic retention time, reasonably proven by the surveyed sources.