The key to improving drying quality and reducing drying time and energy consumption lies in understanding and controlling moisture movement during drying. As wood dries, strains and stresses develop as a result of restraints imposed by moisture gradients and differential shrinkage in wood. So accurately measuring the moisture gradient in wood during drying will be helpful to improving drying quality. In this project, moisture gradients in red oak will be measured through four different techniques----<i><b>bandsaw slicing, Forstner bit layering, flaking and razor blade slicing</i></b>. The first two techniques are found in the literature. The last two are developed in this study. The results obtained with these four techniques were compared, and it was found that the newly developed techniques could get moisture gradients that were closer to the true value. The <i><b>thickness</i></b> of the slice was assumed to affect measuring the moisture gradient because of the environmental influences. So a thickness series was tested with the two new technique----flaking and razor blade slicing. The results showed that there was no slice or flake thickness effect on the moisture gradients.And an optimum slice and flake thickness was determined for the wood industries and research studies. Finally, the <i><b>directional</i></b> effect on transverse moisture movement during kiln drying was examined through measuring moisture gradients in the tangential and radial directions of wood. The results showed that moisture moved slightly faster in the radial direction than in the tangential direction during kiln drying and the moisture gradients in the tangential direction were slightly steeper than those in the radial direction. / Master of Science

Made available in DSpace on 2017-07-21T18:53:18Z (GMT). No. of bitstreams: 1 Lorena Lemos.pdf: 1400448 bytes, checksum: 208ef78ab99ed1032b0c3fc7832c38df (MD5) Previous issue date: 2012-08-03 / Several investigations have been performed to determine the influence of the sugarcane composition in the quality of its products, especially crystal sugar. There is interest in studies about dextran and starch to be causative agents of major problems during the processing of sugarcane and also to be related to the appearance of flakes or precipitated in alcoholic drinks and acidic carbonated beverage. The objective of the present work was to evaluate the influence of these polysaccharides in the formation of flakes in acidic carbonated and alcoholic solutions. Samples of crystal sugar (n = 21) produced in the central-southern Sao Paulo state were analyzed for quantification of dextran and starch and values between 15.39 ± 0.38 and 830.25 ± 2.58 mg/kg and between 49.11 and 299.92 ± 1.14 ± 1.05 mg/kg were found for dextran and starch, respectively. The test evaluated the formation of flake in alcoholic solution at 55 and 89 % v/v ethanol. The 55 % v/v ethanol was performed to read the absorbance of the samples and values between 0.018 ± 0.001 and 1.063 ± 0.010 NTU were found. For the 89 % v/v ethanol solution the formation of flakes in the first 15 hours of storage the test solution was observed. There was reduction of starch content in solution with the methodology used by alcoholic flake and the reduction varied between 13.78 and 34.15 %. The test evaluated the formation of acid flake following the standard methodology and modification of the method by using a 0.8 μm filter for removal of starch. The turbidity readings were lower when using the modified method. The results obtained for the solutions tested according to standard methodology ranged from 3.72 ± 0.17 to 33.46 ± 6.31 NTU and by using the modified method they were between 1.94 ± 0.08 and 10.97 ± 1.04 NTU. All tests showed that dextran and starch present in the samples of crystal sugar show a positive correlation with the results of acid flake and alcohol flake. The formation of these two types of flakes were also interdependent (has a relation). / Várias pesquisas estão sendo realizadas com o objetivo de determinar a influência da composição da cana-de-açúcar na qualidade final de seus produtos, em especial no açúcar cristal. Existe interesse em estudos sobre dextrana e amido por serem agentes causadores de sérios problemas durante o processamento da cana, estando relacionados ao aparecimento de flocos ou precipitados em bebidas ácidas carbonatadas e em bebidas alcoólicas destiladas. O objetivo desse trabalho foi avaliar a influência desses polissacarídeos na formação de flocos em soluções ácidas carbonatadas e em soluções alcoólicas. Amostras de açúcar cristal (n = 21) produzidas na região centro-sul do Estado de São Paulo foram analisadas para quantificação de dextrana e amido. Foram realizados testes para avaliação da formação de floco alcoólico em soluções hidroalcoólicas a 55 e a 89 % v/v etanol e teste para avaliação da formação de floco ácido seguindo método padrão e método com modificação através da utilização de filtro 0,8 μm para retirada do amido. Foram encontrados teores de dextrana entre 15,39 ± 0,38 e 830,25 ± 2,58 mg/kg e teores de amido entre 49,11 ± 1,14 e 299,92 ± 1,05 mg/kg nas amostras de açúcar cristal analisadas. A 55% v/v de etanol foi realizada a leitura de absorbância das amostras segundo teste de floco alcoólico, sendo encontrados valores de turbidez entre 0,018 ± 0,001 e 1,063 ± 0,010 NTU. A 89 % v/v de etanol, foi observada a formação de flocos nas primeiras 15 horas de estocagem da solução teste. Ocorreu redução do amido presente na solução com o método de floco alcoólico utilizado e as reduções variaram entre 13,78 e 34,15%. Foram verificadas reduções das leituras de turbidez com a utilização do método modificado de floco ácido. Os resultados obtidos para as soluções testadas, de acordo com o método padrão, variaram de 3,72 ± 0,17 a 33,46 ± 6,31 NTU e com a utilização do método modificado, ficaram entre 1,94 ± 0,08 e 10,97 ± 1,04 NTU. Todos os ensaios realizados demonstraram que o amido e a dextrana presentes nas amostras de açúcar cristal apresentam relação positiva com os resultados de floco ácido e floco alcoólico. A formação desses dois tipos de flocos se mostrou diretamente relacionada (apresenta relação positiva).

Lake surface water temperatures (LSWTs) of 246 globally distributed large lakes were derived from Along-Track Scanning Radiometers (ATSR) for the period 1991 to 2011. These LSWTs, derived in a systematic manner, presents an ideal opportunity to study LSWT behaviour on a global scale. In this thesis, the annual cycles of lake-mean LSWTs derived from these data quantify the responses of large lakes’ surface temperatures to the annual cycle of forcing by solar radiation and the ambient air temperature. Minimum monthly net surface solar irradiance (netSSI) strongly influences minimum LSWTs of non-seasonally ice covered lakes (where lake-mean LSWT remains above 1 ºC throughout the annual cycle), explaining > 0.88 (R2 adj) of the inter-lake variation in both hemispheres. In some regions, for seasonally ice covered lakes (where lake-mean LSWT remains below 1 ºC for part of the annual cycle) the minimum monthly netSSI is a better predictor than latitude, of the length of the frozen period, which shows the importance of local cloud climatological conditions. Additionally, at lake locations between 1º S to 12º N, the netSSI, shown to peak twice annually, is reflected in the LSWT annual cycle. The summer maximum LSWTs of lakes from 25º S to 35º N show a linear decrease with increasing altitude; -3.76 + 0.17 ºC km-1 (R2 adj = 0.95), marginally lower than the corresponding air temperature -4.15 + 0.24 ºC km-1 (R2 adj = 0.95) decrease with altitude. The start and end of the period where the lake-mean LSWT is greater than 4 ºC shows strong correlation with the spring and autumn 0 ºC air temperature crossing days, (R2 adj = 0.74 and 0.80 respectively). The temporally and spatially resolved LSWT observations allows for a greater practical understanding of LSWT behaviour of large lakes. For example, lakes with a greater LSWT annual range have more observed variability in the LSWT extremes, highlighting that they may be more responsive to changes in the climate than lakes with a low annual range. The nighttime LSWT trends show stronger warming than day-night trends in the all regions, except Europe. The lake centre LSWT trends and absolute values can be generally considered representative of the lake-mean LSWT trends and absolute values. The observed LSWT time series are used to tune a 1-dimensional thermodynamic lake model, FLake. By tuning FLake using only 3 basic lake properties, shown by myself to have the most influence over LSWTs (depth, snow and ice albedo and light extinction co-efficient), the daily mean absolute differences for 244 lakes is reduced from 3.38 + 2.74 ºC (untuned model) to 0.85 + 0.61 ºC (tuned model). The effect of wind speed, lake depth, albedo and light extinction co-efficient on LSWTs is demonstrated throughout the tuning process. The modelled summer LSWT response to changes in ice-off is strongly affected by lake depth and latitude explaining 0.50 (R2 adj, p = 0.001) of the inter-lake variation in summer LSWTs. Lake depth alone explains 0.35 (p = 0.003) of the variation, highlighting the sensitivity of the summer LSWTs of deeper lakes to changes in the ice-off. Statistically significant summer/ maximum month modelled LSWT trends, from 1979-2011 are presented for lakes where the modelled LSWTs are strongly supported by observed LSWTs over the period of available observed LSWTs. For these lakes, the trends show LSWT warming of between 0.73 – 2.10 ºC for 29 lakes in northern temperate regions over the 33 year period (1979 – 2011). The modelled regional trends of all lakes over the same period show least warming in Africa of 0.30 ºC and the greatest warming in Europe, 1.35 º.

The Speedy Delivery (SD) waveform was introduced in patent US 6,441,695 B1 issued August 27, 2002 to the inventor Dr. Robert Flake. In the most basic form, the SD boundary condition is an exponential, D⋅e [superscript α⋅t] . The propagating waveform is described by an analytic, closed form solution of the wave equation in lossy media and has several very special properties. The most surprising property is that the leading edge of the waveform propagates with attenuation but without distortion. The lack of distortion occurs even in lossy transmission media with frequency dependent parameters. This is unlike any other known pulse shape. Additionally, varying the waveforms parameter, α, can vary the propagation velocity and the attenuation of the waveform. Because the exponential waveform is unbounded it cannot continue indefinitely and must be truncated and closed by a non-SD closing edge. This dissertation discusses the transmission behavior and two applications of truncated SD waveforms. A brief analysis of SD propagation in lossy transmission lines is presented and some practical considerations associated with truncating the SD waveforms are addressed. The parameters needed to describe the propagation of the SD waveform are defined and techniques for determining their values are presented. Finally, examples applying these truncated SD waveforms to time domain reflectometry and Communication Technology are presented. / text

M. Tech. Polymer Technology. / The gas permeability of composite epoxy resins formulated with graphene platelets and glass flakes was investigated. The purpose of researching the gas permeability of the composite resins was to develop a possible coating system that could prevent or limit the release of radioactive gases like tritium from irradiated graphite waste which may accumulate in underground repositories. Helium was used as a substitute gas to simulate the diffusive properties of tritium gas.

Yes / In this work, a novel concept in freeze desalination (FD) was introduced. Nowadays the total liquefied natural gas (LNG) production capacity has reached 290 Megatons per year. Its enormous cold energy released from re-gasification can be used in the freeze desalination process to minimize the overall energy consumption. A process of FD on flake ice maker utilizing LNG cold energy was designed and simulated by HYSYS software. An ice bucket on flake ice maker was chosen as seawater crystallizer mainly due to its continuous ice making and removing ice without heat source. A dynamic model of the freezing section has been developed and simulated through gPROMS software. The results show that the consumption of 1 kg equivalent LNG cold energy can obtain about 2 kg of ice melt water. In addition, it is shown that the power consumption of this LNG/FD hybrid process is negligible.

In many numerical weather prediction models, the presence of lakes is simulated crudely, with their effect being neglected in the resulting simulations. However, it has been shown how lakes effect not only their surrounding climate directly, but have an effect to the overall weather evolution and ecosystem. It is therefore vital to improve existing models to take lakes into account, by coupling with smaller models specificaly compiled for a reas with lakes. There have been several sophisticated models to parameterizelakes in a geographical area, which are, on the other hand, computationally expensive and time consuming. A model built specifically on simple physical assumptions, named FLake, aims to provide a solution that is not heavy computationally, but is accurate enough and contains all the necessary physics surrounding the heat budget and temperature of a given lake. For this project, FLake was tried on a lake close to Uppsala, named Erken, where the validity of the model was tested against data archives from Erken Laboratory’s measurement tower. The resulting simulations were very promising regarding the water temperatures, as well as giving out acceptable results for the surface heat fluxes above the lake and the duration of the ice period, as it was modeled by FLake and compared with ice data archives.

Cascas cilíndricas circulares com uma pequena variação de espessura ao longo de seu comprimento, quando submetidas à rotação, apresentam em alguns casos, deslocamentos elásticos de sua superfície externa, tendendo a uma forma de um oval. O objetivo deste trabalho é estabelecer a relação entre a variação de espessura das cascas cilíndricas com a sua deformação devida às forças centrífugas medida durante a rotação utilizando-se dois enfoques, um experimental e outro numérico, no caso o método de elementos finitos (MEF). As cascas cilíndricas estudadas tiveram sua espessura de parede medidas por meio de aparelho de ultra-som, mas por serem fabricadas em ferro fundido cinzento, as suas lamelas de grafita atuam como refletores, o que torna a medição imprecisa. Os resultados da análise numérica encontrados se relacionam bem com os experimentais de maneira qualitativa, mas divergem na forma quantitativa. Modelos de cascas com variação de espessura imposta também foram criados e analisados usando-se o método de elementos finitos de forma a se avaliar o comportamento da casca cilíndrica sob diversas configurações de distribuição da variação da espessura. Sugere-se a pesquisa de novas tecnologias para medições por ultra-som de peças fabricadas de ferro fundido com grafita lamelar. Neste trabalho, a medição da forma oval foi feita utilizando-se sensores de proximidade do tipo \"eddy-current\". / Circular cylindrical shells with small thickness variations along their body, when submitted to rotation, present, in some cases, elastic displacements of their outside surface induced by centrifugal forces leading to final oval like shapes. The main purpose of this study is to establish relationships between thickness variation of the cylindrical shells with their measured deformation during the rotation, due to centrifugal forces, using two approaches, one experimental and the other one numerical, in the latter case the finite element method (FEM). The studied cylindrical shells had their wall thickness measured by means of an ultrasound device. The used material is flake graphite cast iron (gray cast iron). The graphite flakes act as reflectors, what makes such measurements imprecise. The numerical results found are satisfactory in a qualitative way, but they disagree in the quantitative form. Shell models with theoretical imperfections also were created and analyzed using the finite element method in order to evaluate the behavior of the cylindrical shell under several configurations of distribution of the shell thickness variation. Further research is necessary on new technologies to measure the thickness of pieces manufactured of flake graphite cast iron. In this research, the oval shape measurements were done by means of eddy-current proximity sensors.

Submitted by (edna.saturno@ufrpe.br) on 2017-02-08T14:40:10Z No. of bitstreams: 1 Bruna Caritas Souza do Valle Ferreira.pdf: 835355 bytes, checksum: 19a5bc565f7b7a225d1406626b6c919e (MD5) / Made available in DSpace on 2017-02-08T14:40:10Z (GMT). No. of bitstreams: 1 Bruna Caritas Souza do Valle Ferreira.pdf: 835355 bytes, checksum: 19a5bc565f7b7a225d1406626b6c919e (MD5) Previous issue date: 2013-02-18 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The present study aimed to evaluate the effect of replacing fishmeal for hydrolysate fish protein (HFP) and biofloc flour (BF) in diet of marine shrimp Litopenaeus vannamei postlarvae (2mg). The present study aimed to evaluate the effect of replacing fishmeal for hydrolyzed fish protein (HFP) and biofloc flour (BF) in Litopenaeus vannamei postlarvae. The HFP used in the diets formulation were produced from fish industry waste and the biofloc used for BF production was obtained in cultivation tanks of a commercial shrimp farm. Feed for this phase was designed to be isoenergetic and isoproteic. This experiment consisted of six treatments with three replicates each, corresponding to the control treatment T0, using fish meal as the main protein source. The other treatments (T10, T20, T30, T40) were a gradual replacement of fishmeal by HFP and BF in the proportions of 10, 20, 30 and 40% respectively. In the experiment a commercial feed was used as external control. It was a 42 days assay. Shrimp survival was above 99% in all treatments. After statistical analysis to zootechnical parameters (final weight, weight gain, specific growth rate) shrimps fed with formulated diets had better results than the ones fed with commercial feed. Tested parameters had ideal points indicated by regression in levels ranging between 15 and 16% of fishmeal replacement by HFP and associated BF. In the present study we inferred that BF and HFP are potential ingredients to replace fish meal in diets for L. vannamei postlarvae. / A presente dissertação teve como objetivo avaliar o efeito da substituição da farinha de peixe por hidrolisado proteico de peixe (HPP) e farinha de biofloco (FB) na alimentação de pós-larvas (2mg) do marinho camarão Litopenaeus vannamei. O HPP utilizado na elaboração das rações foi produzido a partir de resíduos de uma indústria de pescado. O biofloco para a produção da farinha foi obtido em tanques de cultivo de uma carcinicultura comercial. As rações para esta fase foram elaboradas para serem isoproteicas e isoenergéticas. Este experimento consistiu de seis tratamentos com três repetições cada, correspondendo ao tratamento controle o T0, utilizando a farinha de peixe como principal fonte proteica, e os demais tratamentos com substituição gradual da farinha de peixe por HPP e FB nas proporções de 10, 20, 30 e 40% correspondendo aos tratamentos T10, T20, T30 e T40 respectivamente. No experimento foi utilizado um tratamento com ração comercial que serviu como controle externo. Este ensaio teve duração de 42 dias. A sobrevivência dos camarões cultivados ficou acima de 99% em todos os tratamentos. As respostas estatísticas para os parâmetros de desempenho zootécnico (peso final, ganho de peso, taxa de crescimento específico) indicaram melhores resultados para os camarões alimentados com as rações formuladas quando comparados com os camarões alimentados com ração comercial. Os parâmetros testados tiveram seus pontos ideais indicados pela regressão, em níveis que variaram entre 15 e 16% de substituição da farinha de peixe por HPP e FB associados. Os resultados encontrados neste experimento indicaram o potencial dos ingredientes testados na substituição da farinha de peixe em rações para L. vannamei.

The amount and morphology of the graphite phase largely controls the resulting properties of cast iron. For instance, in flake graphite cast irons the mechanical properties are low while the thermal conductivity is high. This is in contrast with spheroidal graphite cast irons where the mechanical properties are high and the thermal conductivity is low. These differences are due to the different graphite morphologies and must be accounted for in the design work and material selection of cast iron components. In this work the influence of the graphite phase on the elastic and plastic deformation behaviour of cast irons has been studied. The material grades studied originate from castings for marine diesel engine piston rings with different chemical analyses. Two groups of pearlitic cast iron materials were studied; one with differences in graphite morphology and one with grey irons that differed in graphite content. For these different material grades the mechanical properties were correlated to microstructural parameters. In addition to standard uniaxial tensile tests, acoustic emission measurements were used for the study of deformation. When studying the modulus of elasticity of the cast iron it was found that the modulus of elasticity of the inherent graphite phase depends on the roundness of the graphite particles and is due to the strong anisotropy of the graphite phase. A linear correlation between nodularity and the modulus of elasticity of the graphite phase was derived. This correlation made it possible to account for the anisotropy of the graphite phase in the model used. By applying the linear function when modelling the effective modulus of elasticity, a high accuracy between experimental and theoretical values was achieved. Another factor affecting the elastic response when subjecting a cast iron component to tensile load was found to be the plastic deformation that actually occurs at very low strains for all of the studied cast iron grades. It was observed that the plastic deformation in the low strain elastic region, quantified by using acoustic emission measurements, increased linearly with decreasing modulus of elasticity. These measurements showed that the amount of plastic deformation in the elastic region was largely controlled by the graphite morphology. It was concluded that as the roundness of the graphite particles increases, the plastic deformation activity in the elastic region decreases. The plastic deformation activity continued linearly into the pronounced plastic region of the tensile tests. A decrease in roundness or increase in graphite fraction resulted in an increase of the amount of plastic deformation and the strain hardening exponent. A dependence between strength coefficient and graphite fraction was observed. Models for the flow curves for pearlitic cast irons were developed and shown to accurately reproduce the observed experimental curves. The surveys performed and conclusions from this thesis will be helpful in the design of new cast iron materials.