Superheated steam (SS) drying of distillers’ spent grain (DSG) is a more energy efficient alternative to conventional hot air drying. SS drying at sub-atmospheric pressure (also referred to as low pressure) can prevent burning and lowering the quality of the food product. The objective of this study was to design, fabricate, and test a SS drying system that could operate at sub-atmospheric pressure for drying DSG. After the custom designed system was constructed, major problems associated with the system were identified. A number of tests were carried out and modifications were made to the system to resolve technical problems. Distillers’ spent grain was then successfully dried using the system under various levels of temperature from 95 to 115°C and pressure of either -25 or -20 kPa, with a SS velocity from 0.100 to 0.289 m/s.

PhD / Electrostatics of aerosols for inhalation is a relatively new research area. Charge properties of these particles are largely unknown but electrostatic forces have been proposed to potentially influence lung deposition. Investigation on the relationship between formulation and aerosol charging is required to understand the fundamental mechanisms. A modified electrical low pressure impactor was employed to measure the particles generated from metered dose inhalers and dry powder inhalers. This equipment provides detailed size and charge information of the aerosols. The particles were sized by impaction onto thirteen stages. The net charges in twelve of the size fractions were detected and recorded by sensitive electrometers. The drug deposits were quantified by chemical assay. The aerosol charge profiles of commercial metered dose inhalers were product-dependent, which was due to differences in the drug, formulation, and valve stem material. The calculated number of elementary charges per drug particle of size ≤ 6.06 μm ranged from zero to several ten thousands. The high charge levels on particles may have a potential effect on the deposition of the aerosol particles in the lung when inhaled. New plastic spacers marketed for use with metered dose inhalers were found to possess high surface charges on the internal walls, which was successfully removed by detergent-coating. Detergent-coated spacer had higher drug output than the new ones due to the reduced electrostatic particle deposition inside the spacer. Particles delivered from spacers carried lower inherent charges than those directly from metered dose inhalers. Those with higher charges might be susceptible to electrostatic forces inside the spacers and were thus retained. The electrostatic low pressure impactor was further modified to disperse two commercial Tubuhaler® products at 60 L/min. The DPIs showed drug-specific responses to particle charging at different RHs. The difference in hygroscopicity of the drugs may play a major role. A dual mechanistic charging model was proposed to explain the charging behaviours. The charge levels on drug particles delivered from these inhalers were sufficiently high to potentially affect deposition in the airways when inhaled. Drug-free metered dose inhalers containing HFA-134a and 227 produced highly variable charge profiles but on average the puffs were negatively charged, which was thought to be due to the electronegative fluorine atoms in the HFA molecules. The charges of both HFAs shifted towards neutrality or positive polarity with increasing water content. The spiked water might have increased the electrical conductivity and/or decreased the electronegativity of the bulk propellant solution. The number of elementary charges per droplet decreased with decreasing droplet size. This trend was probably due to the redistribution of charges amongst small droplets following electrostatic fission of a bigger droplet when the Raleigh limit was reached.

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

O objetivo deste trabalho é realizar um estudo comparativo das propriedades mecânicas e metalúrgicas em duas peças de ligas de Al-Si produzidas por injeção sob baixa pressão. As peças estudadas referem-se às placas acessórias utilizadas para fornecer sustentação durante a entrada e saída de vaus por carros de combate do Exército Brasileiro, sendo uma nacional e a outra importada. Para a caracterização metalúrgica foram realizados ensaios metalográficos (microscopia óptica e eletrônica). Para a obtenção das propriedades mecânicas foram realizados ensaios de tração, microdureza Vickers e impacto. Quanto aos resultados metalográficos observou-se: na peça nacional, a presença de uma estrutura predominantemente eutética com silício em forma acicular e a fase Al15 (Fe, Mn)3Si2 com morfologia tipo escrita chinesa; na peça importada, foi identificado silício disperso com formato arredondado. A análise da porosidade por gases realizada no canal de alimentação indicou baixos índices para as duas peças. De outro modo, foi observada a presença de porosidades por contração na peça nacional. Nos resultados mecânicos, a peça importada apresentou valores significativamente superiores para a tensão de escoamento e máxima, energia de impacto e deformação. A partir dos resultados obtidos nos ensaios mecânicos realizaram-se simulações no software Solidworks, módulo Simulation, para a determinação da ocorrência de falha quando utilizado por dois carros de combate: o Leopard 1A5, sobre lagartas, e o URUTU, sobre roda. As simulações indicaram falha da peça nacional pelo uso do carro sobre rodas. O resultado em peso da composição química da peça nacional revelou uma liga de alumínio com 12%Si e 0,88%Fe, enquanto a peça importada apresentou 10,38%Si, 0,294%Mg e somente 0,12%Fe. Com a análise dos resultados, conclui-se que os principais fatores da baixa durabilidade da peça nacional foram, preponderantemente, a composição química e a morfologia do silício. / The objective of this research is to perform a comparative study of the mechanical and metallurgical properties in two castings of Al-Si alloys produced by injection under low pressure. The pieces studied refer to soil reinforcing plates used as accessory plates used to provide support during the entry and exit of the Brazilian Army combat vehicles, one national and other imported. For the metallurgical characterization, metallographic analysis by electron and optical microscopy were performed and. To obtain the mechanical properties tensile tests, Vickers microhardness and impact were performed. Regarding the metallographic results, it was observed: In the national piece, the presence of a predominantly eutectic structure with needle-shaped silicon and the Al15(Fe,Mn)3Si2 phase with Chinese writing morphology; In the imported part, dispersed silicon with a rounded shape was identified. The gas porosity analysis performed on the feed channel indicated low indexes for the two pieces.Otherwise, the presence of porosities by contraction in the national piece was observed. In the mechanical results, the imported part presented values significantly higher for the yield stress and maximum, impact energy and deformation. From the results obtained in the mechanical tests it was able to perform simulations on the Solidworks software, Simulation mode, to determine the failures occurrence when used by two battle cars: Leopard 1A5, on caterpillars, and URUTU, on wheels. The simulations indicated failure of the national part by the use of the car on wheels. The weight result of the chemical composition of the domestic part revealed an aluminum alloy with 12% Si and 0.88% Fe, while the imported piece revealed 10.38% Si, 0.294% Mg and only 0.12% Fe. Analyzing the results, it is concluded that the main factors of the low durability of the national piece were, predominantly, the chemical composition and the morphology of the silicon.

O objetivo deste trabalho é realizar um estudo comparativo das propriedades mecânicas e metalúrgicas em duas peças de ligas de Al-Si produzidas por injeção sob baixa pressão. As peças estudadas referem-se às placas acessórias utilizadas para fornecer sustentação durante a entrada e saída de vaus por carros de combate do Exército Brasileiro, sendo uma nacional e a outra importada. Para a caracterização metalúrgica foram realizados ensaios metalográficos (microscopia óptica e eletrônica). Para a obtenção das propriedades mecânicas foram realizados ensaios de tração, microdureza Vickers e impacto. Quanto aos resultados metalográficos observou-se: na peça nacional, a presença de uma estrutura predominantemente eutética com silício em forma acicular e a fase Al15 (Fe, Mn)3Si2 com morfologia tipo escrita chinesa; na peça importada, foi identificado silício disperso com formato arredondado. A análise da porosidade por gases realizada no canal de alimentação indicou baixos índices para as duas peças. De outro modo, foi observada a presença de porosidades por contração na peça nacional. Nos resultados mecânicos, a peça importada apresentou valores significativamente superiores para a tensão de escoamento e máxima, energia de impacto e deformação. A partir dos resultados obtidos nos ensaios mecânicos realizaram-se simulações no software Solidworks, módulo Simulation, para a determinação da ocorrência de falha quando utilizado por dois carros de combate: o Leopard 1A5, sobre lagartas, e o URUTU, sobre roda. As simulações indicaram falha da peça nacional pelo uso do carro sobre rodas. O resultado em peso da composição química da peça nacional revelou uma liga de alumínio com 12%Si e 0,88%Fe, enquanto a peça importada apresentou 10,38%Si, 0,294%Mg e somente 0,12%Fe. Com a análise dos resultados, conclui-se que os principais fatores da baixa durabilidade da peça nacional foram, preponderantemente, a composição química e a morfologia do silício. / The objective of this research is to perform a comparative study of the mechanical and metallurgical properties in two castings of Al-Si alloys produced by injection under low pressure. The pieces studied refer to soil reinforcing plates used as accessory plates used to provide support during the entry and exit of the Brazilian Army combat vehicles, one national and other imported. For the metallurgical characterization, metallographic analysis by electron and optical microscopy were performed and. To obtain the mechanical properties tensile tests, Vickers microhardness and impact were performed. Regarding the metallographic results, it was observed: In the national piece, the presence of a predominantly eutectic structure with needle-shaped silicon and the Al15(Fe,Mn)3Si2 phase with Chinese writing morphology; In the imported part, dispersed silicon with a rounded shape was identified. The gas porosity analysis performed on the feed channel indicated low indexes for the two pieces.Otherwise, the presence of porosities by contraction in the national piece was observed. In the mechanical results, the imported part presented values significantly higher for the yield stress and maximum, impact energy and deformation. From the results obtained in the mechanical tests it was able to perform simulations on the Solidworks software, Simulation mode, to determine the failures occurrence when used by two battle cars: Leopard 1A5, on caterpillars, and URUTU, on wheels. The simulations indicated failure of the national part by the use of the car on wheels. The weight result of the chemical composition of the domestic part revealed an aluminum alloy with 12% Si and 0.88% Fe, while the imported piece revealed 10.38% Si, 0.294% Mg and only 0.12% Fe. Analyzing the results, it is concluded that the main factors of the low durability of the national piece were, predominantly, the chemical composition and the morphology of the silicon.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / This paper aims to scale, build and test a new vortex tube, operating from the use of compressed air at pressures below the pressure ranges typical of this unconventional cooling device for the purpose of obtaining drafts cold for air conditioning. For that were originally studied theoretical and experimental aspects of flow processes through tests performed in the laboratory with a commercial vortex tube. Known influence of geometric parameters (such as the ratio between the length and internal diameter of the tube and the diameter of the diaphragm hole) and the thermophysical properties (such as inlet pressure gauge in the compressed air tube and the mass flow rate of the stream cold) air in the performance of the vortex tube, gave up the step of sizing the same. After engineered and designed parts of the tube, the final steps were the manufacture of pipe and conducting experimental tests, beyond the selection of a photovoltaic array to provide the power required to drive the compressor. The results of the laboratory tests with a vortex tube counter-current type, internal diameter D equal to 16.5 mm and a length equal to fifteen times this value, and configured diaphragm orifice diameter of 0.5D showed that temperatures of the cold air flow of 9.5 ÂC at a mass flow of 40% of the mass flow input are obtained when delivered by the compressor inlet gauge pressure of 3 bar and volumetric flow rate of 3.15 L/s compressed air. / O presente trabalho tem como objetivos dimensionar, construir e testar um novo tubo de vÃrtice, que opere a partir da utilizaÃÃo de ar comprimido em pressÃes abaixo das faixas de pressÃo tÃpicas deste dispositivo de refrigeraÃÃo nÃo-convencional, com o propÃsito de obter correntes de ar frio para climatizaÃÃo. Para tanto, foram inicialmente estudados aspectos teÃrico-experimentais dos processos de escoamento, atravÃs de testes realizados em laboratÃrio com um tubo de vÃrtice comercial. Conhecida a influÃncia dos parÃmetros geomÃtricos (tais como a razÃo entre o comprimento e diÃmetro interno do tubo e o diÃmetro do orifÃcio do diafragma) e das propriedades termofÃsicas (tais como a pressÃo manomÃtrica de entrada no tubo do ar comprimido e o percentual de vazÃo mÃssica da corrente de ar frio) no desempenho do tubo de vÃrtice, deu-se a etapa de dimensionamento do mesmo. Depois de projetadas e desenhadas as peÃas do tubo, as etapas finais foram a fabricaÃÃo do tubo e a realizaÃÃo de testes experimentais, alÃm da seleÃÃo de um arranjo fotovoltaico que forneÃa a potÃncia necessÃria para o acionamento do compressor. Os resultados dos testes em laboratÃrio com um tubo de vÃrtice do tipo contra-corrente, de diÃmetro interno D igual 16,5 mm e comprimento igual a quinze vezes esse valor, e configurado com diafragma de diÃmetro do orifÃcio de 0,5D, mostraram que sÃo obtidas temperaturas da corrente de ar frio de 9,5 ÂC a uma vazÃo mÃssica de 40% da vazÃo mÃssica de entrada, quando fornecido pelo compressor pressÃo manomÃtrica de entrada de 3 bar e vazÃo volumÃtrica de 3,15 L/s de ar comprimido.

The dynamic response of turbine flowmeters in low pressure gas flows (i. e. where the rotational inertia of the fluid is negligible) is well understood and methods for correcting meter signals for a lack of response are available. For liquid flows there has been a limited amount of experimental work on the response of meters to step changes but no reports have been found of the response of meters to sinusoidally pulsating flows. "Small" turbine meters are expected to behave differently from "large" meters for a number of reasons: a smaller meter would generally have: (1) a larger percentage of tip clearance leakage flow; (2) less fluid momentum between the meter blading; and, (3) less fluid friction forces on the effective surface area. In this research, arbitrarily, meters up to size 25 mm were defined as small; and within this study, meters of size 6 mm to 25 mm were investigated. The aim of the research was to investigate and to understand the response of small turbine meters to pulsating liquid flows and to provide methods for correction. Three approaches were used: (1) application of an existing theoretical model of turbine meter behaviour; (2) an experimental investigation of meter performance in pulsating flows; and (3) simulation of flow behaviour through one selected meter using CFD and extending the simulation to predict the rotor dynamics and, hence, the response of this meter to specified cases of pulsating flow. A theoretical model developed by Dijstelbergen (1966) assumes frictionless behaviour and that flow is perfectly guided by meter blading through the rotor and that fluid within the rotor envelope rotates as a "solid body". Results from this theoretical model applied for pulsating flows showed that there was likely to be positive error in predicted mean flow rate (over-registration) and negative error for predicted values of the amplitude of the pulsations (amplitude attenuation). This behaviour is due to the fundamental asymmetry between flows with increasing and decreasing angle of attack relative to the meter blades, throughout a pulsation cycle. This qualitative behaviour was confirmed by experimental work with meters up to size 25mm working with pulsation frequencies up to 300 Hz. For low frequency pulsations (below 10 Hz), the over-registration errors were within the limits of specified meter accuracy. At higher frequencies and larger pulsation amplitudes, the largest over-registration observed was 5.5 % and amplitude attenuation could be as large as 90 %. The dependence of these errors on both the flow pulsation amplitude and frequency were investigated. The theoretical model was also used as a basis for generating correction procedures, to be applied to both the mean flow and the pulsation amplitude measurements. The results from the CFD simulation showed qualitative good agreement with the experimental data. The same kind of meter error trends were observed and it was shown to provide a better correlation with the experimental trends than the theoretical model derived from Dijstelbergen. From the CFD simulation, the causes of over-registration and amplitude attenuation in turbine flowmetering were understood through the investigation of rotor dynamics coupled with fluid behaviour around meter blading within the pulsation cycle. The CFD results were used to evaluate fluid angular momentum flux and to review the validity of the assumption that fluid within the rotor "envelope" rotated as a solid body. For the case investigated, whilst the assumption that flow is perfectly guided is not inappropriate, the volume of fluid assumed to rotate as a "solid body" was found to be significantly less than the rotor envelope volume.

The thesis deals with the assessment of a low pressure sewer system (LPS) in the village of Hrádek u Sušice during its test operation. It assesses the functionality of the LPS, parameters of operation and lists types of failures, which were found during the test operation, as well as the causes for the failings. For the purpose of determination of the LPS functionality and causes of failures, continual measurements of pressure have been made on selected sites followed by a thorough analysis of the data.

Dans les analyses de sûreté du futur réacteur à fusion ITER, on anticipe un accident de perte de vide susceptible de mettre en suspension des particules produites et déposées sur les parois du tore. L’objectif de cette thèse est de fournir des données expérimentales fiables afin de développer et valider un modèle de mise en suspension (MES), prenant en compte la basse pression et prévoyant les fractions de particules mobilisées lors d’un tel évènement. Pour ce faire, des expériences ont été effectuées en fonction des paramètres clés — diamètre des particules, vitesse de frottement et masse volumique — entrant dans le mécanisme de MES. L’analyse de la granulométrie des particules de tungstène produites en tokamak met en évidence des diamètres allant de 0,1 à 10 µm. Les résultats expérimentaux de MES de dépôts monocouche sont en bon accord avec le model Rock’nRoll lorsque les particules sont uniquement mobilisée par le fluide. Cependant, une mobilisation des particules fines par agglomération, non prise en compte dans les modèles de MES, a été mise en évidence. Mes expériences ont aussi révélé l’importance de la structure (porosité et épaisseur) des dépôts multicouches dans le mécanisme de MES avec, là encore, une mobilisation par agglomération de particules. L’effet de la basse pression dans la mise en suspension a été étudié entre 10 et 1 000 mbar et doit se poursuivre à plus basse pression. Mes résultats de MES montrent une réduction du frottement dans les forces aérauliques à basse pression. Enfin, les mesures de la cinétique du phénomène de MES ont mis en évidence trois zones distincts avec un effet à court terme, un effet à long terme et une zone de transition qui devront être pris en compte dans un calcul de MES. / In ITER, a loss of vacuum accident is likely to re-suspended particles produced and deposited on the torus walls. The thesis purpose is to provide reliable experimental data to develop and validate a re-suspension model, taking into account the low pressure and predicting the amount of particles mobilized during such event. Experiences were carried out as a function of key parameters — particle diameter, friction velocity and density of the atmosphere — entering in the re-suspension mechanism. The size distribution of tungsten particles specific to fusion reactors was obtained from a collection in the AUG tokamak: modes at 0,8 µm and at 1,6 µm. The adhesion forces, adjustment parameters of most re-suspension models, were measured by Atomic Forces Microscopy (AFM). Experimental data of re-suspension of monolayer and multilayers deposits were acquired in two wind-tunnels: BISE-II (Saclay) and AWTS-II (Aarhus). For the monolayer deposits, the re-suspended particle fractions were measured by size bins, for friction velocities of 1.0 and 1.5 m.s-1 at 1,000 mbar, and of 1.0 m.s-1 at 300 mbar. Regarding the multilayers deposits, the re-suspension was measured for five surrounding pressures (25, 60, 10, 300 and 1,000 mbar), constituting a valuable data base for the development of a re-suspension model taking into account the mobilisation by particle clustering and the effect of a low pressure. Finally, measurements of the MES phenomenon kinetic highlighted three distinct regions with a short-term effect, long-term effect and a transition region which must be taken into account in a MES calculation.

The purpose of this master thesis is to provide a reliable methodology to predict the forced response of a monoblock bladed drum from a low pressure compressor. Pre-test forced response calculations have already been made at Techspace Aero in 2013. Now that experimental data are available, the methodology has to be adapted to ensure the best numerical-experimental correlation possible. The final goal is that, at the end of the thesis, engineers at Techspace Aero will be able to launch reliable forced response simulations within a short amount of time. For the sake of confidentiality, some data are not revealed, such as the engine name, some numerical values (forced response, aerodynamic damping, frequency of the mode etc…) and axis scales. In this paper, the study focuses on the forced response of a rotor blade from the first stage under the excitation from the upstream stator. The mode under investigation is the 2S2, the one that responded during the experiment. The TWIN approach is used to compute the forced response of the rotor blade. With this approach, a steady stage computation has first to be carried on as an initialization. Then two unsteady computations are necessary. The first, without blade motion, will provide the excitation aerodynamic forces. The aerodynamic damping will be extracted from the second one, where the motion of the blade is imposed on a given eigenmode. The forced response can then be computed with these two results and some additional structural data.  The results will be compared to the experimental value.