Dissertations / Theses: 'Drying methods'

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Beaudry, Claudia. "Evaluation of drying methods on osmotically dehydrated cranberries." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32756.

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Since cranberry skin is thick and has low porosity, skin pretreatments were considered before drying in order to facilitate water diffusion. Mechanical and chemical pretreatments were considered, by cutting the fruits in half, by making pin holes in each cranberry, and by dipping the fruits in an alkaline solution.
A second pretreatment seemed necessary when drying cranberries in order to reduce their tartness. Cranberries were osmotically dehydrated, by immersing them in osmotic solutions of sucrose or high fructose corn syrup.
Once the pretreatment conditions were selected, four drying methods were tested on the pretreated cranberries. These methods included hot air drying, freeze-drying, vacuum drying and a combination of hot air and microwaves. A quality evaluation of the dried samples was also performed, including evaluation of overall appearance, taste, color, water activity, rehydration capacity and texture. (Abstract shortened by UMI.)

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Ribeiro, Luciana Carneiro. "Acerola powder: drying methods and evaluation of stability." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13078.

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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico
The objective of this research was to obtain powder from the pulp of integral acerola two drying methods (spray-dryer and freeze drying), and the determination of physical and chemical stability and hygroscopic and morphological characteristics. Acerola pulps were acquired in the trade of Fortaleza. The pulp was characterized and post as the physicochemical, colorimetric and morphological parameters. The study of the stability of the powders was carried out in three distinct packaging for a period of 90 days. The adsorption isotherms were also determined. The results indicated optimal conditions for drying spray-dryer using drying temperature of 154 ÂC and the pulp concentration maltodextrin 17,1%, while in the lyophilizer, 19,1% maltodextrin with lyophilization time of 24 hours. All physico-chemical parameters evaluated in the whole pulp undergo change after drying. The drying spray-dryer powder generated with lower humidity, and lyophilization produced a more hygroscopic powder, with a greater degree of caking, and better color preservation, the pH being a parameter of small variation. The study of the stability of acerola pulp powder obtained by different drying methods allowed us to observe increased humidity and coordinate a* b* and decreased ascorbic acid and brightness. The use of laminated packaging laminate vacuum was effective to maintain moisture and hygroscopic powder, with less loss of ascorbic acid for packaging laminda vacuum. The BET model best fit the adsorption isotherms of the lyophilized powder acerola pulp, while for the spray-dryer model Oswin better adjusted to 25 ÂC, and Henderson model for 35 and 45 ÂC. Morphological characterization showed by analysis of Microcopia Scanning Electron (SEM), X-ray diffraction (XRD) spectroscopy and Fourier Transform Infrared (FTIR-ATR) that the lyophilization process generates an amorphous powder and adding maltodextrin protects the frame of samples and permits lower moisture absorption also show similar composition between samples, and a higher absorbance obtained is lyophilized in the whole sample.
O objetivo desta pesquisa foi a obtenÃÃo de pÃ a partir da polpa de acerola integral por dois mÃtodos de secagem (spray-dryer e liofilizaÃÃo), assim como a determinaÃÃo da estabilidade fÃsico-quÃmica e caracterÃsticas higroscÃpicas e morfolÃgicas. As polpas de acerola foram adquiridas no comÃrcio de Fortaleza-CE. Caracterizou-se a polpa e os pÃs quanto a parÃmetros fÃsico-quÃmicos e colorimÃtricos e morfolÃgicos. O estudo da estabilidade dos pÃs foi realizado em trÃs embalagens distintas por um perÃodo de 90 dias. Determinou-se ainda as isotermas de adsorÃÃo. Os resultados indicaram condiÃÃes Ãtimas de secagem em spray-dryer utilizando temperatura de secagem de 154ÂC e concentraÃÃo de maltodextrina na polpa de 17,1%, enquanto para o liofilizador, 19,1% de maltodextrina com tempo de liofilizaÃÃo de 24 horas. Todos os parÃmetros fÃsico-quÃmicos avaliados na polpa integral sofrem variaÃÃo apÃs secagem. A secagem em spray-dryer gerou pÃ com menor umidade, e a liofilizaÃÃo gerou um pÃ mais higroscÃpico, com maior grau de caking, e melhor preservaÃÃo da cor, sendo o pH um parÃmetro de pequena variaÃÃo. O estudo da estabilidade das polpas de acerola em pÃ obtidas por diferentes mÃtodos de secagem permitiu observar aumento da umidade e das coordenadas a* e b* e diminuiÃÃo do Ãcido ascÃrbico e luminosidade. O uso de embalagens laminada e laminada a vÃcuo mostrou-se eficaz para a manutenÃÃo da umidade e higroscopicidade dos pÃs, com menor perda de Ãcido ascÃrbico para a embalagem laminada a vÃcuo. O modelo de BET melhor se ajustou as isotermas de adsorÃÃo o pÃ de polpa de acerola liofilizado, enquanto para o spray-dryer o modelo de Oswin melhor se ajustou a 25ÂC, e o modelo de Henderson para 35 e 45ÂC. A caracterizaÃÃo morfolÃgica mostrou pelas anÃlises de Microcopia EletrÃnica de Varredura (MEV), DifraÃÃo de Raios-X (DRX) e Espectroscopia de Infravermelho com Transformada de Fourier (FTIR-ATR) que o processo de liofilizaÃÃo gera um pÃ amorfo e que a adiÃÃo de maltodextrina protege a estruturadas amostras e permite uma menor absorÃÃo de umidade, ainda mostra composiÃÃo similar entre as amostras, e que uma maior absorbÃncia Ã obtida em amostra integral liofilizada.

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Crévier, Hélène A. "Cultural methods for dehydrating onion production in Quebec, with particular reference to the fluid drilling technique." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65969.

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Echard, Dalton. "Drying Methods for the Fabrication of Polymer Foam Material." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4096.

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This is a report on the study of the drying of nanoporous polymer foam material fabricated by photolithogtaphic methods. Three drying methods were employed, which were air drying, supercritical drying and freeze drying. After fabrication and drying, physical properties of the polymer foams were measured. These measurements included density of the material, Young’s modulus, surface area, and the shape of the skeletal particles. The measurements determined the effect of the polymer concentration and the effect of drying methods. It was determined that polymer concentration had a much larger effect on the properties of the materials than the drying method.

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Blount, Thomas Richard. "Evaluation of Methods to Control Mold on Hardwood Pallets." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23231.

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The objectives of this project were:
1.ï¿½ï¿½ï¿½ï¿½To compare the drying cost and drying time for oak and poplar pallets for the following mold mitigation strategies for hardwood pallets: air drying, forced air drying (fan shed), kiln drying to 25% moisture content and chemical treatment, and
2.ï¿½ï¿½ï¿½ï¿½Develop and evaluate a procedure for preventing and controlling mold growth on heat treated hardwood pallets
Twenty red oak pallets and twenty yellow-poplar pallets were tested for each drying method to compare costs and to determine drying times. ï¿½Additional pallets were obtained to conduct a more thorough air drying procedure. ï¿½Drying data was extrapolated to allow estimates of the drying time from green (83% moisture content for poplar and 64% moisture content for oak) to 25%. ï¿½
After the pallets reached the desired 25% moisture content, they were placed in a 40ï¿½" enclosed trailer, inoculated with mold (Aspergillus, Stachybotrys, and Penicillium) and were left undisturbed for a period of 14 days. ï¿½After the 14 day incubation period, the pallets were inspected for mold using the ASTM D-4445 Standard Test Method for Fungicides for Controlling Sapstain and Mold on Unseasoned Lumber. ï¿½
A comparison of drying costs was then conducted to determine which method was the most cost efficient based on the data obtained in this study. ï¿½The cost to treat the pallets with each treatment was calculated including electrical cost, labor, and tax values. ï¿½In addition to the cost comparison, a Net Present Value (NPV) was calculated to determine which method produced the best outcome over a longer period of time.
Two heat treatment and drying schedules were then developed to meet both IPPC-ISPM #15 requirements and achieve the desired 25% moisture content with minimal degrade. ï¿½This was accomplished by testing several HT/drying schedules on green yellow-poplar and white oak pallets until the pallets met the criteria for being heat treated and had minimal degrade. ï¿½The schedules developed are a modified oak HT/KD schedule that required 30 hours to complete and a modified poplar HT/KD schedule that required 16 hours to complete.
The results demonstrated that that mold would not grow on the pallets stored in an enclosed container when the dew point is not reached. Air-drying pallets, chemical application in conjunction with air-drying pallets, fan shed drying pallets and kiln drying pallets to a 19-24% moisture content was demonstrated to prevent mold growth on oak and yellow poplar pallets. Estimates for the time required to dry yellow-poplar and oak pallets to 19% and 25% moisture content were developed for air-drying, forced air-drying and kiln drying for the conditions experienced in Blacksburg, VA between 7/30/2008 and 11/10/2008. Air-drying pallets was found to have the lowest daily operational cost but not the lowest total drying cost. ï¿½Fan shed drying had the lowest drying cost to achieve 25% moisture content. ï¿½Kiln drying was the most expensive daily and total cost, but yielded the fastest method of drying pallets to 25% moisture content. A NPV cost comparison showed that over a 3 year (36 month) time period, fan shed drying is the most cost effective method of drying pallets based on the values used in this study. Given the environmental conditions experienced between 7/30/2008 and 11/10/2008, no mold grew on the air-dried, fan shed, and kiln dried pallets during the drying process.

Master of Science

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Perumal, Rajkumar. "Comparative performance of solar cabinet, vacuum assisted solar and open sun drying methods." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18283.

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Tomato (Lycopersicon esculentum L.var) is one of the most important vegetables in our diet and dried tomato products are becoming popular for the preparation of various food items. Though sun drying has been used for the preservation, it is a slow process and the quality of the dried product is often inferior due to contaminations. Therefore, a lab model solar cabinet and vacuum assisted solar dryers were developed to study the drying kinetics of tomato slices (4, 6 and 8 mm thicknesses) and the results were compared individually with open sun drying under the weather conditions of Montreal, Canada. The drying kinetics using thin layer drying models and the influence of weather parameters such as ambient air temperature, relative humidity, solar insolation and wind velocity on drying of tomato slices were evaluated. During drying, it was observed that the temperatures inside the solar cabinet and vacuum chamber were increased to 63 and 48oC when the maximum ambient temperature was only 30oC. The tomato slices of 4, 6 and 8 mm thicknesses could be dried from 94.0 to 11.5% wet basis moisture content, respectively in 300, 420 and 570 min using solar cabinet, in 360, 480 and 600 min using vacuum assisted solar dryer and it took 435, 615 and 735 min under open sun drying method. The quality of tomato slices in terms of physicochemical parameters such as colour retention, water activity, rehydration capacity and ascorbic acid retention were evaluated and the overall study concluded that good quality dehydrated tomato slices could be produced by using vacuum assisted solar dryer compared to solar cabinet and open sun drying methods. The Page model was found to be better in describing the drying kinetics of tomato slices in all the drying methods studied.
La tomate (Lycopersicon esculentum L. var) est une importante source nutritive de notre alimentation et les tomates séchées gagnent en popularité dans de nombreuses préparations alimentaires. Le séchage naturel est la méthode traditionnelle utilisée pour la production de tomates séchées, cependant c’est un processus lent et la qualité du produit séché est variable et sujette à la contamination. Un séchoir solaire et un séchoir solaire sous-vide furent donc développés afin d’étudier le séchage solaire de tranches de tomates (4, 6 et 8 mm d’épaisseur) en comparaison au séchage naturel sous les conditions météorologiques de Montréal, Canada. La cinétique du séchage des tranches de tomates suivant des modèles en couches minces a été établie en fonction de l’influence des conditions météorologiques telles que la température ambiante, l’humidité relative, le rayonnement solaire et la vitesse du vent. Lors du séchage dans le séchoir solaire et le séchoir solaire sous-vide, la température interne des deux séchoirs a atteint 63° et 48°C respectivement alors que la température ambiante était de 30°C. Les tranches de tomates de 4, 6 et 8 mm d’épaisseur ont pu être séchées d’un taux d’humidité de 94% à 11.5% (état humide) et ce après 300, 420 et 570 minutes en utilisant le séchoir solaire, en 360, 480 et 600 minutes grâce au séchoir solaire sous-vide, alors qu’il en a pris 435, 615 et 735 minutes par séchage naturel. La qualité des tranches de tomates a été évaluée en fonction de certains paramètres physico-chimiques tels que la stabilité de la couleur, l’activité de l’eau, la capacité de réhydratation, et la conservation de l’acide ascorbique. Des tranches de tomates séchées de meilleure qualité peuvent être produites par séchage solaire sous-vide en comparaison avec le séchage solaire et le séchage naturel. La modélisation de Page offre une très bonne représentation$

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Thabot, Arnaud Henri. "Porosity Analysis in Starch Imbued Handsheets - Challenges using impulse drying and methods for image analysis." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19804.

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In about 30 years of experiments and development, impulse drying is now considered as a well known technology and a good candidate in the constant effort to save energy in the paper industry. The drying section is indeed the most expensive section in the process of paper production. However, this potential technology has a major disadvantage, stopping its implementation in the industry. Paper, which is a porous material with a variable compressibility, experienced a sudden release of energy at the nip opening during impulse drying. Under these conditions of high intensity process (both in temperature and pressure), the fiber mat has a tendency to delaminate. This web disruption is a critical issue against impulse drying. This thesis comes up with a new approach to the problem. These last years, the technology itself has been addressed in this issue and many improvements have been reached in terms of energy release (heat transfer control, material coating ). The novel idea is then to investigate the inner structure of the paper once it has been coated with starch to a large extent (up to 10 or 20% of the relative basis weight). Starch is known for its large use in industry, but also its capability to expand under high temperature. Hence, both relative strength and bulking effects are investigated in this thesis, using numerous experiments with variable temperatures and pressures, along with ultrasonic testing and image analysis. We have the opportunity to appreciate the phenomenon of heat transfer and mass transport in the coated medium, while reaching promising results in terms of strength and bulk. These are finally investigated using scanning electron microscopy as a first step toward a pore expansion model for starch imbued handsheets.

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Boström, Charlotta, and Anna Rosén. "Fibre-to-Board - Validation of the Simulation Model and Development of Laboratory Methods to Receive Input Data." Thesis, Karlstad University, Faculty of Technology and Science, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-598.

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Fibre-to-board is a simulation model developed at Stora Enso Research Centre Karlstad. Within this model isotropic hand sheet properties are used as input data for prediction of the final multi ply board properties. In order to improve and verify the calculations from simulations in Fibre-to-board so that these will correspond better with the results from the measurements on the paper/board machine, it was requested at RCK to investigate the possibility to optimize the input data to the model.

Standardized hand sheet forming always results in sheets with properties far away from those produced on a machine. Therefore the aim with this Master thesis was to modify the laboratory procedure to receive hand sheets with properties closer to machine sheets. To achieve this, it was investigated how different parameters affect the sheet properties and if the hand sheet making process could be improved.

When freely dried sheets were investigated it was found that sheets pressed with a wire clothing between the blotting paper and the hand sheet were less cockled than sheets pressed against only blotting papers. These sheets also tend to have a higher density. The cockling i.e. as a result from shrinkage was also reduced when the sheets were dried between slightly weighted wire clothing. Neither wire clothing nor orientated blotting papers during pressing eliminate the influence of anisotropic blotters on the shrinkage for isotropic hand sheets.

It was also examined how the fine material influences sheet properties. The results showed that an increase in fines content result in higher shrinkage, higher density, increased TSI, more cockling and decreased air permeability.

Different pressing loads and an increased density did not have much influence on the shrinkage. The density for freely dried sheets increased with higher load, but the results did not reach machine sheet densities, when the laboratory platen press was used. It might be difficult to receive freely dried hand sheets with higher densities. This is because fibres in freely dried sheets tend to relax after pressing, which will influence the density. Another press than the platen press used in these studies might compensate this matter. An increased pressing load resulted in less cockled sheets.

The basis weight did not seem to have that large affect on the shrinkage when using machine chest furnish, therefore the basis weight on hand sheets used as input data to the simulation model Fibre-to-board might not be that important.

It was studied how different plies and SW/CTMP pulp in a mixture affect the shrinkage. The results showed that the shrinkage increased with a higher SW content. It was also found that there is a linear relation between the total shrinkage of a SW/CTMP pulp mixture and the shrinkage for each individual pulp.

In order to verify the Fibre-to-board model a simulation finally was performed. Furnishes and CD profiles of board were collected from a particular board machine within the Stora Enso Group. Properties from hand sheets made of furnishes were used as input data and the machine CD profiles were used as references. The CD TSI value corresponded with the value received from measurements on the machine board, but the MD TSI value did not. The shrinkage calculated on machine sheets did not coincide with the shrinkage from the simulation in Fibre-to-board.

There are insecurities in the results from shrinkage measurement on the board CD profile due to the lack of width measurement during the process, which complicates the validation of the Fibre-to-board model.

Fibre to board är en simulerings modell framtagen vid Stora Enso Research Centre Karlstad. Modellen används för att prediktera krympning och styrkeegenskaper hos en bestämd kartongbana. Indata till modellen hämtas ifrån isotropa laboratorieark. För att förbättra och verifiera erhållna resultat från simuleringsmodellen så att de korresponderar bättre med värden från kartongmaskinen fanns det ett önskemål från RCK om att undersöka möjligheten att optimera indata till modellen.

Laboratoriearktillverkning enligt standard resulterar alltid i ark med egenskaper som ligger långt från maskin arkens. Därför är syftet med detta examensarbete att modifiera arktillverkningsmetoden så att laboratorieark med egenskaper närmare de för maskinark kan erhållas. För att lyckas med detta undersöktes det hur olika parametrar påverkar pappersegenskaperna och om tillverkningsmetoden kunde förbättras.

Vid undersökning av fritorkade ark upptäcktes att ark som pressats med viraduk mellan läskark och laboratorieark blev mindre buckliga än ark som pressats med enbart läskark. Dessa ark hade också en något högre densitet. Buckligheten som är en följd av krympningen reducerades också när arken torkades mellan viraduk under lätt belastning. Läskarkens inverkan på de isotropa arken kunde inte elimineras genom att använda viraduk vid pressning, inte heller genom att växla läskarken så att deras MD riktning orienterades olika.

Även finmaterialets inverkan på pappersegenskaperna undersöktes. Resultaten visade att ett ökat finmaterial innehåll ger ökad krympning, högre densitet, ökat dragstyvhetsindex, buckligare ark och en minskad luft permeabilitet.

Det visade sig att olika presstryck ger arken en högre densitet men krympningen påverkades inte märkbart. Densitet i samma nivå som på maskinark kunde däremot inte erhållas med laboratorieplanpress. Detta kan bero på att fibrerna i fritorkade ark relaxerar efter pressning, vilket ger en lägre densitet. För att kunna få högre densitet kanske en annan press än den planpress som användes i dessa studier kan införas. Det kunde även konstateras att ett ökat presstryck ger mindre buckliga ark.

I dessa studier, där ark tillverkades av färdiga skiktblandningar från maskinkar, hade inte ytvikten på arken någon större inverkan på krympningen. Detta tyder på att ytvikten på arken som används som indata inte har så stor inverkan vid simulering i modellen Fibre-to-board.

Det undersöktes även hur skikten i ett två-skikts ark och en blandning av LF/CTMP massa påverkar krympningen. Resultaten visade att krympningen ökar med en högre andel LF och att det finns ett linjärt samband mellan den totala krympningen för en blandning av LF/CTMP massa och krympningen för de enskilda massorna.

För att kunna verifiera beräkningsmodellen Fibre-to-board utfördes slutligen en simulering. Skiktblandningar och tvärsprofiler från kartong togs ut från en specifik pappers maskin inom Stora Enso koncernen. Egenskaperna på laboratorieark gjorda av skiktblandningarna användes som indata till simuleringsprogrammet och kartongprofilerna från pappersmaskinen användes som referens. Dragstyvhetsindex i CD stämde bra överens med de mätningar som gjordes på maskinarken, men dragstyvhetsindex i MD skiljde sig. Krympningen som beräknades på maskinarken överensstämde inte med det simulerade resultatet. Det förekommer en osäkerhet i krympmätningarna som gjordes på kartong profilerna, då det idag inte förekommer någon mätutrustning på pappersmaskinen, som bestämmer bredden mellan press- och torkpartiet. Detta komplicerar valideringen av Fibre-to-board modellen.

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Stockinger, Allan Joseph. "Optimizing lanthanum (III) hydroxide by varying drying methods to maximize surface area to adsorb arsenic in water /." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1447803.

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Thesis (M.S.)--University of Nevada, Reno, 2007.
"May 2007." Includes bibliographical references (leaves 72-75). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2007]. 1 microfilm reel ; 35 mm.

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Lam, Melanie. "Drying of red spring wheat seedlings (Triticum aestivum L.) by various methods and investigation of its phenylalanine ammonialyase stability in an in vitro protein digestion." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/1625.

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Phenylketonuria and hyperphenylalanemia are autosomal recessive inborn errors of phenylalanine metabolism that are caused by mutations in the phenylalanine hydroxylase gene. Due to the stringency of the present dietary therapy, alternative treatments are being studied. Phenylalanine ammonia-lyase (PAL) is one of the potential dietary supplements for these patients. PAL is a well-studied plant enzyme which breaks down phenylalanine into trans-cinnamic acid and ammonia (Camm and Towers, 1973). It is found in the cytoplasm of the plant cells and is naturally encapsulated by plant cell walls which may protect it against the acidic pH environment in the gastrointestinal tract. It presumably degrades ingested Phe that circulates in the intestinal lumen. In this study, red spring wheat seedlings (Triticum aestivum L.) found to contain high PAL activity naturally were investigated as a potential alternative oral therapy. Specifically, the objectives were (1) to evaluate different drying methods on generating concentrated and dried preparation of wheat seedlings containing high levels of PAL activity; (2) to examine the retention of PAL activity over three months of storage under various storage conditions; (3) to determine the stability of PAL activity in simulated human digestion condition to establish if further study of using plant source enzyme in vivo is warranted. Freeze-drying (FD) was found to have retained the most activity (>90 % recovery dry wt basis) compared to air-drying (AD) and vacuum-microwave drying (VMD) for both leaf and residual seed/root samples. Pre-freezing of leaf tissues at -18 °C before FD significantly retained the highest PAL activity compared to pre-freezing at -25 °C, -35 °C, and -80 °C (P<0.05). Over three months of storage, 60-80 % of PAL activity was recovered in leaf and —100 % was recovered in residual seed/root tissues after storage at -20 °C. After in vitro protein digestion, 36% and 42 % of PAL activity was recovered in fresh leaf and root tissues respectively; however, FD tissues were found to be susceptible to proteases and acidic environment and no activity was recovered after three hours of in vitro protein digestion. High performance liquid chromatography (HPLC) analysis of the residual Phe after in vitro protein digestion confirmed that fresh tissues had significantly higher conversion of Phe than that of FD tissues. Together, these results suggest that red spring wheat seedlings may have potential as a dietary supplement for phenylketonuric patients while further study to enhance PAL activity in plant preparations is required.

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Wittner, Marc Oliver [Verfasser]. "Application of Air-Core-Liquid-Ring atomization in spray drying processes: Proof of concept and Methods for process design / Marc Oliver Wittner." München : Verlag Dr. Hut, 2020. http://d-nb.info/1220567892/34.

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Tseng, Chien Ling. "The environment qualities evaluation of a degraded area in recuperation and the drying process of a Brazilian soil using nonconventional methods at micrometric scale." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-18072017-085726/.

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Soil is a fundamental resource in the environment, its sustainable use is vital to food supply and, consequently, life continuity on the Earth. However, the currently status of this resource in the world is critical and, therefore, the need of soil recovery measures and methods to evaluate it is urgent. The aim of this study is to provide a holistic evaluation about soil architecture at different recovery states, as well as its interaction with fluid in the environment by using nonconventional methods. It was organized a tool package that allows to analyze soil physical at geometric, morphometric and energy scope, to show in a more efficient way, which physical parameters indicate the physical and environmental quality. Subsequently, this package was applied to the study of six types of managements in different stages of development by using of physical parameter derived from the package; It was also analyzed the efficiency of recovery techniques under different perspectives. In addition, the soil-water dynamic was evaluated in a particular condition by using the same tools, offering knowledge about this interaction in the environment along the time. Finally, it is expected that this work can bring new insight on preservation and recovery of this environmental resource.
O solo é um recurso fundamental no meio ambiente, seu uso sustentável é vital para prover alimentos e consequentemente a continuidade da vida na Terra. No entanto, estado atual desse recurso no mundo encontra-se em condição crítica, logo as medidas de recuperação devem ser adotadas urgentemente, consequentemente a necessidade de métodos adequados para avaliação dessas medidas. O objetivo desse estudo é proporcionar uma avaliação holística sobre a arquitetura do solo em diferentes estados de recuperação, assim como sua interação com fluido no meio ambiente utilizando métodos não convencionais. Logo, foi organizado um pacote de ferramentas que permitam analisar a física solo no âmbito de geometria, morfometria e energia, proporcionando parâmetros físicos que indicam a qualidade física e ambiental; Em seguida esse pacote foi aplicado no estudo de seis tipos de manejos com diferentes estágios de desenvolvimento, envolvendo os parâmetros físicos derivados do pacote, mostrando assim a eficiência das técnicas de recuperação sob diferentes perspectivas; Assim foi realizado também a avaliação da dinâmica da água no solo em uma situação particular utilizando as mesmas ferramentas, proporcionando conhecimentos sobre o essa interação no meio ambiente ao longo do tempo. Finalmente, espera-se com esse trabalho novos olhares sobre esse recurso precioso no meio ambiente.

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Bai, Shujun. "Understanding physicochemical stability of proteins in solution and development of new analytical methods for freeze-dried protein formulations /." Connect to full text via ProQuest. Limited to UCD Anschutz Medical Campus, 2008.

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Thesis (Ph.D. in Pharmaceutical Sciences) -- University of Colorado Denver, 2008.
Typescript. Includes bibliographical references (leaves 134-146). Free to UCD Anschutz Medical Campus. Online version available via ProQuest Digital Dissertations;

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Bueche, Blaine. "The Effect of PEG-Insulin and Insulin Hexamer Assembly on Stability in Solution and Dry Powders. Hexamer Assembly of PEGylated-Insulin and Insulin Studied by Multi-Angle Light Scattering to Rationally Choose the pH and Zinc Content for Analytical Methods and Formulations of Dry Powders." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/5688.

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The objective of this research is to further define the relationship between the charge state of insulin, and the self assembly properties of insulin and PEGylated insulin in solution. Polyethylene glycol (PEG) chains were covalently attached to insulin in order to evaluate their impact on insulin's systemic duration of action after pulmonary dosing. This thesis will focus on the assembly properties of the PEG-insulin and insulin, and also demonstrate how the charge state, which was modified by the covalent attachment of PEG, relates to different modes of behavior by anion and cation exchange chromatography. In addition, explain how modifying the assembly state extends to improving formulation properties of spray-dried insulin powders. This thesis is an investigation into the relationship of insulin's charge state controlled by pH and how the charge state affects the self assembly of insulin, especially when the zinc ion is removed. Ionic interaction is one of the major forces affecting insulin assembly. The theory that a change in the charge state of insulin could modulate the ionic interaction and reduce hexamer formation at alkaline conditions was investigated. Experiments were designed to measure the level of hexamer with light scattering, and the amount of hexamer was then correlated with the pH and zinc content of the solutions. The importance of the charge state of the monomer and its behavior extends to chromatography and purification modes as well. Specifically, the purification of various species of PEGylated insulin presents a challenge. By varying mobile phase pH which induces the charge to insulin, an ion exchange method demonstrated very high resolution and controllable interaction between the ion exchange media and the insulin derivatives. A highly accurate method for determining molecular weight and thus the average associated state of insulin in solution has been developed using the MALS (Multi-Angle Light Scattering). Insulin concentration, pH, and metal ion concentrations, were in pharmaceutically relevant ranges. The MALS method was developed to evaluate how the parameters above affect the self-assembly properties of insulin, and use the assembly properties to improve formulations of insulin or PEGylated insulin. To use the light scattering technique the dn/dc (change in refractive index with change in concentration) is required. During the method development, the dn/dc of insulin was measured at 690 nm, and a value of 0.185 mL/g based on theory was confirmed. A novel approach for preparing insulin powders with improved chemical stability, based on maintaining the dissociation of hexamers in solution during the spray drying process was developed. The mode presented here is to remove the zinc ions from solution, increase the pH from 6.6 to 7.8, and maintain a low concentration of insulin approximately 2 to 15 mg/mL. Each of these factors alone decreases the hexamer population in solution, but by combining all three factors, hexamers are driven to very low levels of equilibrium. The increased stability of the powders is predominately related to the decrease in covalent insulin dimer (CID). The data presented correlates a reduced hexamer population in the solution with lower levels of CID's in the dry powder compared to controls. The CID formation rate was reduced by 40% compared to a control.

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Alena, Tomšik. "Sušenje i ekstrakcija lista sremuša (Allium ursinum L.) u cilju dobijanja funkcionalnih proizvoda sa bioaktivnim potencijalom." Phd thesis, Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, 2018. https://www.cris.uns.ac.rs/record.jsf?recordId=107458&source=NDLTD&language=en.

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Cilj ove doktorske disertacije je bio odrediti niz tehnoloških postupaka koji bi omogućili iskorišćenje sremuša u prehrambene i farmaceutske svrhe u svežem ili suvom stanju, kao biljne droge za pripremu različitih formi ekstrakata bogatih bioaktivnim jedinjenjima izolovanih iz njega.List sremuša bere se u vrlo kratkom vremenskom periodu tokom proleća, a nakon branja njegovi listovi vrlo brzo venu i gube svoja senzorna, nutritivna i funkcionalna svojstva, zbog čega je dostupnost ove biljne sirovine vremenski vrlo ograničena. Zbog toga su ispitani uslovi skladištenja svežeg lista sremuša kako bi se sagledala trajnost sremuša za konzumiranje u svežem stanju, ali i mogućnost primene skladištenog sremuša za ekstrakciju bioaktivnih jedinjenja. Za dobijanje osušenog lista sremuša ispitan je uticaj različitih tehnika sušenja (konvektivno i vakuumsko sušenje) i temperature sušenja (40, 50, 60 i 70 °C) na sadržaj bioaktivnih komponenti u osušenom proizvodu. Primenom odgovarajuće tehnike sušenja, povećava se stabilnost i dostupnost listova sremuša za potrebe prehrambene i farmaceutske industrije. Primenom savremenih ekstrakcionih tehnika kao što je ekstrakcije superkritičnim ugljen-dioksidom, ekstrakcije subkritičnom vodom i ultrazvučne ekstrakcije, ispitan je uticaj procesnih parametara različitih ekstrakcionih tehnika, poput ultrazvučne ekstrakcije (temperatura, vreme ekstrakcije, snaga ultrazvuka, uticaj rastvarača) i ekstrakcije subkritičnom vodom (temperatura, vreme ekstrakcije, dodatak modifikatora), superkritične ekstrakcije ugljen-dioksidom (pritisak i temperatura), dok je maceracija kao konvencionalna tehnika ekstrakcije primenjena za poređenje efikasnosti modernih ekstrakcionih postupaka. U dobijenim ekstraktima ispitan je sadržaj polifenolnih komponenti, antioksidantna aktivnost i sadržaj sumpornih jedinjenja u cilju optimizacije ekstrakcionih parametara i radi utvrđivanja uslova ekstrakcije pri kojima se postiže najveći kvalitet ekstrakata u pogledu sadržaja ciljanih bioaktivnih komponenti. Za odabrane ekstrakte ispitan je antimikrobni potencijal na različite Gram pozitivne i Gram negativne bakterijske sojeve. Za dobijanje stabilnijih formi odabranih ekstrakata primenjena je enkpasulacija spray drying i spray congeling tehnikom. Enkapsuliranim ekstraktima su određene fizičko-hemijske osobine (hemijski sastav, sadržaj vlage, higroskopnost, moć rehidratacije, WAI i WSI) i biološka aktivnost (antimikrobna i antioksidativna aktivnost).
The aim of this doctoral dissertation was to determine various technological procedures that would enable the use of fresh and dryed wild garlic leaves in foods and pharmaceutical industry, as a herbal drug or nutraceuticals.The availability period of fresh wild garlic is very short and only during the spring season. After harvest, the leaves are quite perishable, wither very quickly and lose their sensory, nutritive and functional properties. This makes the availability time of this herbal raw material very limited. Therefore, the conditions for storing the fresh leaves of wild garlic and the influences of storing conditions on composition of bioactive compounds were examined in order to extend their use in fresh state. In order to obtain dry herbal drug for extraction, influence of various drying techniques (convection and vacuum drying) and drying temperatures (40, 50, 60, 70 °C) were examinated. The stability and availability of wild garlic in food and pharmaceutical industries was extended by drying. The influence of process parameters of different modern extraction techniques - ultrasonic extraction (temperature, extraction time, ultrasonic power, solvent effect) and subcritical water extraction , extraction time, modifier addition), supercritical carbon dioxide extraction (pressure and temperature) - was examined, while maceration (as a conventional extraction technique) was used to evaluate the efficiency of modern extraction methods. The obtained extracts were analysed in terms of the polyphenolic content, the antioxidant activity and the content of sulfur compounds in order to optimize the extraction parameters and determine the extraction conditions for achieving the highest quality of extracts in terms of the content of the target bioactive components. Antimicrobial potential for different Gram positive and Gram negative bacterial strains was tested for selectedextracts. To obtain more stable forms of selected extracts encapsulation techniques - spray drying and spray congeling - were applied. Encapsulated extracts were evaluated in terms of physico-chemical properties (chemical composition, moisture content, hygroscopicity, rehydration power, WAI and WSI) and biological activity (antimicrobial and antioxidant activity).

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Smart, Alexander Jay. "A Comparison of Lithium-Ion Cathode Vertical Homogeneity as Influenced by Drying Rate and Drying Method." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8637.

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During lithium-ion battery electrode fabrication, slurry drying conditions influence the resulting microstructure of electrodes. It has been found that the drying conditions can result in non-uniform cathode microstructures and material distributions. Accelerated drying, for example, is widely assumed to cause the binder in an electrode to migrate within the slurry, which can contribute to adhesion failure, and ultimately capacity fade and reduced battery life. While there are some conflicting studies regarding the aspects of accelerated drying that cause binder migration, there is not a widely used standard metric for measuring the gradient of binder across the thickness of an electrode. In this work, the vertical heterogeneity of electrodes, as measured using energy-dispersive X-ray spectroscopy (EDX), is correlated with different drying methods and rates. An improved metric for measuring the binder gradient in electrodes is proposed. For the electrodes in this study, binder migration is minimally affected by the drying method and the normalized binder gradient does not increase with increased drying rate. The results are compared to a drying physics model, and it is shown that further development of current models that predict binder gradient as a function of drying rate will need to be modified to more fully capture the physics of slurry drying.

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Zorica, Drinić. "Ekstrakcija industrijske konoplje (Cannabis sativa L.)." Phd thesis, Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, 2020. https://www.cris.uns.ac.rs/record.jsf?recordId=114780&source=NDLTD&language=en.

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U okviru ovog rada izvršeno je ispitivanje različitih procesa ekstrakcije herbe industrijske konoplje. Za ekstrakciju određenih bioaktivnih jedinjenja primenjene su klasične tehnike ekstrakcije, maceracija i Soxhlet ekstrakcija, dok su od savremenih metoda primenjene ultrazvučna ekstrakcija, mikrotalasna ekstrakcija, ekstrakcija vodom u subkritičnom stanju i ekstrakcija ugljendioksidom u superkritičnom stanju. Praćenjem uticaja ulaznih promenjivih (procesnih parametara) na odabrane izlazne promenjive (sadržaj bioaktivnih jedinjenja ili antioksidativnu aktivnost) za svaku tehniku ekstrakcije pojedinačno utvrđeni su optimalni uslovi ekstrakcije. Nakon izvršenog poređenja odabrana je najadekvatnija tehnika ekstrakcije za pripremu tečnog ekstrakta koji će biti transformisan u suvi ekstrakt primenom metode sušenja raspršivanjem. Prilikom dobijanja suvog ekstrakta ispitan je uticaj različite koncentracije nosača na kvalitet ekstrakata i efikasnost sušenja. Dobijeni ekstrakti su okarakterisani u pogledu fizičkih i hemijskih osobina. Sadržaj kanabinoida u tečnim ekstraktima suve herbe industrijske konoplje ispitanih u ovoj doktorskoj disertaciji je bio u opsegu od 0,4314 mg/mL CBD-a i 0,0364 mg/mL THC-a (u optimalnom ekstraktu dobijenom maceracijom) do 1,0420 mg/mL CBD-a i 0,0430 mg/mL THC-a (u optimalnom ekstraktu dobijenom mikrotalasnom ekstrakcijom). U ekstraktima koji su nepolarnog karaktera i koji su dobijeni primenom Soxhlet ekstrakcije sadržaj CBD-a i THC-a je bio 64,40 i 2,90 mg/g, dok je primenom superkritične ekstrakcije dobijen sadržaj CBD-a i THC-a u opsegu od 76,1193 do 163,1111 mg/g i od 4,1746 do 6,5803 mg/g. Tečni ekstrakti dobijeni primenom vode i etanola kao ekstragensa bili su bogati flavonoidima i fenolima, a utvrđeno je i da imaju značajnu antioksidativnu aktivnost, dok su ekstrakti dobijeni Soxhlet ekstrakcijom i ekstrakcijom ugljendioksidom u superkritičnom stanju bili bogati lipofilnim jedinjenjima i terpenima. Ovako dobijeni ekstrakti predstavljaju visokovredne proizvode koji imaju veliki potencijal za upotrebu u farmaceutskoj industriji.
Various extraction processes of the aerial parts of industrial hemp were examined. From classic extractions, maceration and Soxhlet extraction were applied, while from novel methods, ultrasound-assisted extraction, microwave-assisted extraction, subcritical water extraction and supercritical carbon dioxide extraction were applied. By monitoring the influence of the input variables on the selected output variables for each extraction, the optimal extraction conditions were determined separately. After a comparison of all the extraction processes tested, microwave-assisted extraction was selected to prepare the liquid extract for spray drying. The effect of different carrier concentrations was examined during the preparation of the dry extract. The extracts obtained were characterized in terms of physical and chemical properties. The content of cannabinoids in liquid extracts of dry Cannabis sativa herba examined ranged from 0.4314 mg/mL for CBD and 0.0364 mg/mL for THC in the optimum extract obtained by maceration to 1.0420 mg/mL for CBD and 0.0430 mg/mL for THC in the optimum extract obtained by microwave-assisted extraction. The CBD and THC content in extract obtained by Soxhlet extraction was 64.4000 mg/mL and 2.9000 mg/mL, respectively, while the highest content of CBD and THC in the supercritical carbon dioxide extract was 163.11 and 6.5803 mg/g. In addition to cannabinoids, the liquid extracts obtained were rich in phenols and flavonoids, and have considerable antioxidant activity, while the extracts obtained by Soxhlet extraction and supercritical carbon dioxide were rich in lipophilic compounds and terpenes. The extracts mentioned above are high value products which have great potential for implementation in the pharmaceutical industry.

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SANG, YINGZI. "Possibility of enhancing algae drying by integrating infrasound." Thesis, KTH, Industriell ekologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-205318.

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With the aim of designing an infrasound-integrated technology which can enhance the algae drying performance, this thesis provided the theoretical possibility of using infrasound as an algae dehydration technology. To test the relation between algae drying speed and other three parameters namely sound frequency, sound pressure and sample mass, four major experimental groups including initial experiments and core experiments with fifteen sub-experimental groups are designed. Results of the experiments shows expected accordance with the theoretical inferences of infrasound being an algae drying technology. Experiment steps and specifications are presented as the research methodology. A real system with the drying capacity of 2 ton fresh algae per day are designed based on the experimental calculations and results. Several revisions including air circulation and infrasound resonance are made when scaling up the research from experimental level up to industrial level. Other specifications of the real system design follow the experiment results with regard of the research consistency. Freeze drying technology is selected for the comparative cost analysis including manufacturing costs and energy consumptions. Results shows infrasound-integrated technology has a relatively low energy consumption whereas it costs more manufacturing costs than freeze drying technology. Research assumptions, limitations and recommendations for this research are described in this article. From the author’s perspective, this paper can be used as an initiation and instruction for larger scale researches in regard of infrasound-integrated algae dehydration/drying.

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Mutshekwa, Ndivhuho. "Effect of time-based hot air drying method on chemical composition of jatropha zeyheir tea." Thesis, University of Limpopo, 2017. http://hdl.handle.net/10386/1914.

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Thesis (M. Sc. (Agriculture)) --University of Limpopo, 2017
Tea is one of the most popular consumed beverages in the world, which has beneficial properties such as anti-oxidization, anti-carcinoma and preventing arteriosclerosis. The major essential components of catechins present in tea leaves, includes epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), epicatechin (EC), gallocatechin (GC) and catechin (C). Influence of time-based hot air drying method on chemical composition of the Jatropha zeyheri Sond, widely consumed in rural communities of Zebediela (Khureng village), Limpopo Province, South Africa, was investigated. Four treatments, namely; 0, 24, 48, and 72 hours, were arranged in completely randomised design (CRD), replicated five times. The study demonstrated that drying significantly increased total phenolic content, total antioxidant capacity and tannin content. It also demonstrated that drying significantly increased minerals elements; Mg, K, P, S, Al, Co, Mn, Si and Zn content and decreased Na, Ca and Ni and Zn quantities. Sodium-potassium ratio was very low across drying periods. Drying time did not significantly influence proximate chemicals; energy, protein, carbohydrates, ash and fibre content. Moisture and fat were significantly increased by drying period. Results of the study suggested that time-based hot air drying method improved the chemical composition of J. zeyheri, which has the potential of enhancing nutrition in marginal rural communities of Limpopo Province.

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Dalmaz, Nesip. "Modeling And Numerical Analysis Of Single Droplet Drying." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606487/index.pdf.

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MODELING AND NUMERICAL ANALYSIS OF SINGLE DROPLET DRYING DALMAZ, Nesip M.Sc., Department of Chemical Engineering Supervisor: Prof. Dr. H. Ö
nder Ö
ZBELGE Co-Supervisor: Asst. Prof. Dr. Yusuf ULUDAg August 2005, 120 pages A new single droplet drying model is developed that can be used as a part of computational modeling of a typical spray drier. It is aimed to describe the drying behavior of a single droplet both in constant and falling rate periods using receding evaporation front approach coupled with the utilization of heat and mass transfer equations. A special attention is addressed to develop two different numerical solution methods, namely the Variable Grid Network (VGN) algorithm for constant rate period and the Variable Time Step (VTS) algorithm for falling rate period, with the requirement of moving boundary analysis. For the assessment of the validity of the model, experimental weight and temperature histories of colloidal silica (SiO2), skimmed milk and sodium sulfate decahydrate (Na2SO4&
#8901
10H2O) droplets are compared with the model predictions. Further, proper choices of the numerical parameters are sought in order to have successful iteration loops. The model successfully estimated the weight and temperature histories of colloidal silica, dried at air temperatures of 101oC and 178oC, and skimmed milk, dried at air temperatures of 50oC and 90oC, droplets. However, the model failed to predict both the weight and the temperature histories of Na2SO4&
#8901
10H2O droplets dried at air temperatures of 90oC and 110oC. Using the vapor pressure expression of pure water, which neglects the non-idealities introduced by solid-liquid interactions, in model calculations is addressed to be the main reason of the model resulting poor estimations. However, the developed model gives the flexibility to use a proper vapor pressure expression without much effort for estimation of the drying history of droplets having highly soluble solids with strong solid-liquid interactions. Initial droplet diameters, which were calculated based on the estimations of the critical droplet weights, were predicted in the range of 1.5-2.0 mm, which are in good agreement with the experimental measurements. It is concluded that the study has resulted a new reliable drying model that can be used to predict the drying histories of different materials.

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Kandil, Amr Essam. "Spray drying as a method for fabrication of particulate pulmonary delivery systems." Thesis, University College London (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432046.

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Shafiai, Siti Habibah. "Lattice Boltzmann Method for simulating shallow free surface flows involving wetting and drying." Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539515.

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Petrova, Irina. "Influence of Drying Method on NMR-based Metabolic Profiling of Human Cell Lines." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1565356630902222.

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Truscott, Simon. "A heterogenous three-dimensional computational model for wood drying." Queensland University of Technology, 2004. http://eprints.qut.edu.au/15960/.

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The objective of this PhD research program is to develop an accurate and efficient heterogeneous three-dimensional computational model for simulating the drying of wood at temperatures below the boiling point of water. The complex macroscopic drying equations comprise a coupled and highly nonlinear system of physical laws for liquid and energy conservation. Due to the heterogeneous nature of wood, the physical model parameters strongly depend upon the local pore structure, wood density variation within growth rings and variations in primary and secondary system variables. In order to provide a realistic representation of this behaviour, a set of previously determined parameters derived using sophisticated image analysis methods and homogenisation techniques is embedded within the model. From the literature it is noted that current three-dimensional computational models for wood drying do not take into consideration the heterogeneities of the medium. A significant advance made by the research conducted in this thesis is the development of a three - dimensional computational model that takes into account the heterogeneous board material properties which vary within the transverse plane with respect to the pith position that defines the radial and tangential directions. The development of an accurate and efficient computational model requires the consideration of a number of significant numerical issues, including the virtual board description, an effective mesh design based on triangular prismatic elements, the control volume finite element discretisation process for the cou- pled conservation laws, the derivation of an accurate dux expression based on gradient approximations together with flux limiting, and finally the solution of a large, coupled, nonlinear system using an inexact Newton method with a suitably preconditioned iterative linear solver for computing the Newton correction. This thesis addresses all of these issues for the case of low temperature drying of softwood. Specific case studies are presented that highlight the efficiency of the proposed numerical techniques and illustrate the complex heat and mass transport processes that evolve throughout drying.

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Bosch, Thomas [Verfasser], and Gerhard [Akademischer Betreuer] Winter. "Aggressive Freeze-Drying : a fast and suitable method to stabilize biopharmaceuticals / Thomas Bosch. Betreuer: Gerhard Winter." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2014. http://d-nb.info/1065610173/34.

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Grenier, Jérôme. "Hydrogel poreux pour la reconstruction osseuse : élaboration, caractérisation et mise en œuvre dans un bioréacteur à perfusion." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC091.

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La reconstruction de larges défauts osseux nécessite l’implantation de matrices jouant le rôle d’échafaudage, biocompatibles, biodégradables et capables de promouvoir la régénération osseuse. Cette thèse porte sur un biomatériau poreux dont certaines formulations ont déjà démontré leur potentiel de régénération osseuse chez le rat et la chèvre. Il est obtenu par lyophilisation d’un hydrogel de polysaccharides (pullulane et dextrane) réticulé chimiquement.Dans un premier temps, on s’intéresse à l’influence des paramètres du procédé d’élaboration sur la structure poreuse du biomatériau. Les matrices sont caractérisées à chaque étape du procédé : par rhéométrie en mode dynamique lors de la réticulation, par cryomicroscopie électronique à l’issue de la congélation, par microtomographie à rayon X à l’état déshydraté et enfin par microscopie confocale à l’état solvaté. Il apparaît que la structure poreuse obtenue à l’issue de la lyophilisation dépend fortement de la microstructure de la glace formée lors de l’étape de congélation : chaque pore résulte de la croissance d’un à quelques cristaux. Le nombre et la taille des grains de glace après solidification complète sont étroitement liés à la germination secondaire, un phénomène qui est exacerbé par la présence du réseau polymère.Deux paramètres d’élaboration contrôlant la structure poreuse sont particulièrement examinés : d’une part la quantité de réticulant introduit lors de la synthèse de l’hydrogel (qui modifie la longueur de corrélation du réseau polymère), d’autre part la température de germination lors de la congélation. Après sublimation de la glace, le biomatériau obtenu est extrêmement poreux (92 − 94%).L’efficacité d’ensemencement des matrices déshydratées est quantifiée à l’aide de suspensions de microsphères de différents diamètres et de suspensions de cellules : le seuil de coupure est de l’ordre du diamètre moyen des pores secs. Après hydratation (concomitante à l’ensemencement), la porosité est nettement plus faible (~ 30%) et le diamètre moyen des pores hydratés diminue d’un facteur 2 à 4 en fonction de la densité de réticulation.Dans un second temps, cette thèse met en place une démarche d’étude in vitro portant sur les interactions des cellules osseuses (ostéoblastes de souris) avec le biomatériau. L’objectif est de disposer d’un système d’étude mimant les conditions physiologiques afin d’optimiser les propriétés de régénération osseuse du biomatériau. Le choix d’un dispositif in vitro permet de faire l’économie d’expérimentations animales. Un bioréacteur à perfusion est choisi comme modèle d’étude car il permet un environnement 3D où les transferts de matière peuvent être contrôlés. Une caractérisation multi-échelle est mise en place : marquage biologique et microscopie confocale à l’échelle des amas cellulaires et des matrices, imagerie par résonnance magnétique à l’échelle du bioréacteur. Celle-ci est complétée par la simulation numérique de l’hydrodynamique et du transport d’oxygène dissous dans le bioréacteur où chaque phase (fluide, hydrogel, amas cellulaires) est décrite avec une résolution spatiale de 55 µm correspondant à celle de l’IRM. Les équations de Navier-Stokes et l’équation de convection-diffusion sont simulées à l’aide de méthodes de Boltzmann sur réseau, particulièrement adaptées aux géométries complexes. On étudie l’influence de la taille des amas cellulaires et de la densité d’amas sur le champ de concentration d’oxygène en vue d’optimiser leur viabilité.Cette thèse donne des éléments clés pour contrôler la microstructure d’un hydrogel poreux destiné à l’ingénierie tissulaire et fournit un protocole expérimental d’étude en bioréacteur à perfusion couplé à une modélisation numérique pour optimiser les propriétés d’usage du biomatériau
The reconstruction of large bone defects requires the implantation of scaffolds that are biocompatible, biodegradable and able to promote bone healing. This thesis focused on a porous biomaterial that had already demonstrated its osteo-inductive properties after implantation in rats and goats. This biomaterial is produced by freeze-drying of a chemically crosslinked polysaccharide-based (pullulan and dextran) hydrogel.First, we studied the influence of the process parameters on the properties of the biomaterial porous structure. The scaffolds were characterized at each step of the fabrication process: by dynamic rheometry during crosslinking, by electron cryo-microscopy just after freezing, by X-ray microtomography in the dry state and finally by confocal microscopy in the swollen state. It appears that the porous structure obtained at the end of freeze-drying strongly depends on the microstructure of the ice formed during the freezing stage: each pore results from the growth of one to a few crystals. Ice grains are mostly generated by secondary nucleation, this phenomenon is enhanced by the presence of the polymer network. Two parameters controlling the porous structure were particularly examined: the amount of crosslinker that reacts with the polysaccharides (which affects the correlation length of the polymer network), and the nucleation temperature at the onset of freezing. After sublimation of ice, the biomaterial becomes highly porous (92-94%).The seeding efficiency of the dried scaffolds was quantified using suspensions of narrow-sized calibrated microspheres and suspensions of cells: the seeding threshold is in the order of the average diameter of the dry pores. After swelling (occurring simultaneously with seeding), porosity is significantly lower (~ 30%) and the average diameter of the swollen pores is 2 to 4 times lower than in the dry state (depending on the crosslink density).Secondly, we investigated in vitro the interactions between the porous hydrogel scaffolds and osteo-competent cells derived from a mouse cell line. The experimental device was designed in order to mimic the physiological conditions. A perfused bioreactor was chosen because of its ability to generate a 3D environment with controlled shear stress and controlled solute concentration. Such a system should help to optimize the biomaterial while reducing the use of animal experiments. A multiscale characterization of the bioreactor tests was implemented: use of biomarkers and confocal microscopy at the spheroid and scaffold scales, magnetic resonance imaging at the bioreactor scale. We also investigated the hydrodynamics and the transport of oxygen within the bioreactor using computational fluid dynamics: fluid, hydrogel and spheroids were described at the MRI spatial resolution (i.e. 55 µm), NavierStokes equations and advection-diffusion equation were simulated using lattice-Boltzmann methods. These methods are indeed particularly suitable for complex geometries. The influence of organoid size and density on the oxygen concentration field was studied to optimize cell viability.This thesis provides key elements to control the microstructure of the porous hydrogel scaffolds and proposes a workflow to optimize the bone healing properties of the biomaterial by coupling tests in perfused bioreactors, experimental characterizations and numerical modelling

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Hamamousse, Nadjet. "Caractérisation des propriétés physiques des matériaux impliqués dans l'accélération des feux de forêt." Thesis, Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0621.

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Les feux de forêt ravagent chaque année des millions d'hectares de végétation mettant en danger la vie de l’homme et la stabilité de la faune et la flore. Sur le terrain, les pompiers ont signalé l’existence d’un type particulier de feux qui apparait lors de la propagation. Ce sont les embrasements généralisés éclairs, ils ont un comportement assez inhabituel. D’abord, ils commencent par se propager de manière normale, puis, leur vitesse augmente soudainement. C’est ce qui s’est passé à Palasca en 2000 lorsque le feu s’est transformé en piège mortel mettant fin à la vie de deux jeunes pompiers et à la carrière de quatre autres qui ont été grièvement blessés. Une surface de 5 ha est partie en fumée en quelques minutes. Cette thèse est consacrée à la caractérisation des matériaux qui peuvent contribuer à l’accélération brutale des feux. D'abord, nous avons validé le modèle de Petit Monde sur un cas réel. L'étude de sensibilité a permis d'identifier les paramètres prépondérants du modèle qui influent la vitesse de propagation. Comme l'inflammabilité est affectée par la présence d'eau et les gaz inflammables, nous avons caractérisé expérimentalement ces deux paramètres
Every year, fires devastate millions of hectares of wildland and cause serious impacts on natural, economical, and human resources. Firefighters highlighted that some forest fires behave differently; they are called flashover. These fires are characterized by a sudden acceleration. Those fires are called flashover. Such phenomenon was observed in September 2000 in Palasca where two young firefighters passed away, four were seriously injured and about 5 hectares burned in few minutes. This thesis is devoted to the characterization of the physical properties of materials that can contribute to the sudden and unpredictable acceleration of fires. First, the Small World network model was validated on a historical fire. The sensitivity analysis of the model allows identifying the most important parameters that affect the fire spread. Since the flammability depends on the fuel moisture content and the flammable volatile organic compounds, these two parameters were characterized experimentally

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28

Oummadi, Siham. "Drying behaviour of ceramic green bodies : experimental characterization and numerical modelling." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0112.

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Cette thèse s’inscrit dans un objectif à long terme de contrôle et de pilotage en temps réel du séchage des produits céramiques. Pour cela, cette étude se décompose en deux volets. Une première partie expérimentale qui porte sur la détermination en temps réel des paramètres de séchage (température de l’échantillon, teneur en eau et variations dimensionnelles par méthode optique). Une seconde partie, quant à elle, consiste à étudier l’évolution des propriétés physiques des matériaux pendant le séchage pour ensuite construire un modèle numérique macroscopique qui utilise ces données expérimentales. Deux matériaux céramiques ont été choisis pour cette étude : une alumine et une argile kaolinitique. L’alumine a été choisie pour son utilisation fréquente dans les céramiques techniques et le kaolin dans les céramiques traditionnelles. La partie expérimentale de cette étude a permis de déterminer le comportement macroscopique au séchage des deux matériaux ainsi que d’évaluer la dépendance des propriétés physiques (en particulier le coefficient de diffusion et la conductivité thermique) avec la teneur en eau. De plus, une étude à une échelle plus petite par RMN et microscopique par MEB environnemental a permis de mettre en relation l’évolution des propriétés physiques avec la localisation de l’eau au sein du matériau pendant le séchage. Puis, à partir de l’évaluation de nombreuses situations de séchage, les prédictions numériques se sont avérées être en bon accord avec les résultats expérimentaux. Pour conclure, ce modèle représente un bon moyen pour contrôler l’étape de séchage
The present thesis is part of a long-term objective to control the drying step of ceramic green bodies in real-time. Given this general aim, the present work is based on two complimentary parts. The first part deals with the measurement of drying parameters (sample temperature, moisture content and dimension changes by an optical method). Then, since the ultimate objective of this work is the construction of a numerical model, an experimental evaluation of physical properties involved during drying is made for input into the model. The current study is focused on two technologically important materials frequently used in the ceramic industry which are alumina and clays (kaolin here). Alumina is one of most common raw materials used in technical ceramics and kaolin is typically used in traditional ceramics. Experimentally, the macroscopic drying behaviour of both materials zqs determined as well as the dependence of physical properties (in particular the diffusion coefficient and the thermal conductivity) on moisture content as drying proceeds. Furthermore, a study on the spatial distributions of water within the ceramic green body at different scales (MRI and ESEM) is used to interpret how physical properties vary with moisture content. Then, from the examination of numerous situations of drying, we concluded that the proposed numerical model yields good predictions of moisture content and the green body temperature. These parameters can help to evaluate progress in the drying step with eventual feedback in process control

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Gray, Brian Robert. "Retention of the harpagoside content in dried Harpagophytum procumbens (Devil's Claw) root through controlled drying and the application of near infrared spectroscopy (NIRS) as rapid method of determination." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53576.

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Thesis (MSc Food Sc )--Stellenbosch University, 2003.
ENGLISH ABSTRACT: The effect of drying conditions on the retention of harpagoside, a glucoside iridoid found in the indigenous Southern African plant Harpagophytum procumbens (Devil's Claw), was investigated. Additionally, the feasibility of using near infrared spectroscopy (NIRS) as a rapid and nondestructive analytical tool for the prediction of the iridoids harpagoside (HS), 8-p-coumaroyl harpagide (8pCHG) and moisture contents, as well as the HS:8pCHG ratio in Devil's Claw was also studied. Due to the purported medicinal activity ofthe tuberous secondary roots, Devil's Claw is of commercial interest with a well established export market in Germany. The stability of HS during processing has, however, never been investigated and the current study evaluated the effect of three drying methods (sun, tunnel and freeze-drying), as well as three tunnel-drying temperatures (40°C, 50°C and 60°C, dry bulb temperature) on HS content. Methanolic extracts (70% methanol-water) were analysed by high-performance liquid chromatography (HPLC) and a multiple extraction test (n = 12) indicated a 91.70% recovery for HS. The comparative drying results showed significant (P < 0.05) differences between tunnel and freeze drying on the one hand and sun-drying on the other, with the latter being the most detrimental technique. In comparing tunnel-drying temperatures, at a constant relative humidity (RH) of30%, drying at 40°C showed the lowest retention ofHS, differing significantly (P < 0.05) from that at 50°C. Drying at 60°C did not differ significantly (P > 0.05) from either of the other two conditions, but also resulted in lower retentions ofHS content than drying at 50°C. Overall, freeze-drying showed excellent results for HS retention (1.565% ± 0.394%; mean ± standard deviation), but economic constraints limit the commercial application of this drying method. Although further study is required to optimise tunnel-drying conditions, this method indicated acceptable and practical results (1.526% ± 0.396%), especially with conditions set to 50°C and 30% RH (1.750% ± 0.438%). Future research should concentrate on elucidating the degradation mechanisms of HS during processing, transport and storage of dried Devil's Claw root. The analysis of dried, ground Devil's Claw root by NIRS was referenced to HPLC analyses of the same methanolic extracts used in the drying studies. The spectra were generated on two different NIRS instruments by measuring diffuse reflectance of the powder whilst calibrations were performed by partial least squares regression. Both independent data set validation and full cross-validation were used to evaluate the performance and predictive abilities of the various models. Excellent moisture content (MC) calibrations were developed with a standard error of prediction (SEP) ofO.24% (range: 2.44% to 10.43%) and correlation coefficient (r) of 0.99. For the given MC range, the model performed very well against the standard error of laboratory (SEL) ofO.14%. Considering the sensitivity of the HPLC reference method (SEL = 0.035%), the HS content calibration (range: 0.693% to 2.244%) performed admirably with an SEP ofO.134%. The available range was, however, relatively small and future NIRS studies should incorporate a larger range if possible. The 8pCHG model (range: 0.069% to 0.290%) performed similarly, with a standard error of cross-validation of 0.028% and SEL of 0.007%. By inclusion of a second species, H. zeyheri, both the 8pCHG content and especially HS:8pCHG ratio (range: 1.84 to 34.48) calibrations were evaluated as possible methods of distinguishing between species. With 8pCHG values of ca. 0.9%, good separation was achieved for the first model but, contrary to previous studies, the ratio was found to be less successful. Principle component analysis of the spectra, however, showed great potential as a qualitative tool for this purpose. It is believed that NIRS can become an invaluable tool for the division of Devil's Claw into export classes, depending on HS content. This content is, however, dependant on the drying conditions used and drying parameters should be optimised to ensure the best possible quality and retention ofHS.
AFRIKAANSE OPSOMMING: Die invloed van drogingskondisies op die behoud van harpagosied, 'n iridoïed glikosied wat in die inheemse Suider-Afrikaanse plant, Harpagophytum procumbens (Duiwelsklou) voorkom, is ondersoek. Die uitvoerbaarheid van naby infra-rooi spektroskopie (NIRS) as 'n vinnige en niedestruktiewe analitiese metode vir die voorspelling van die inhoud van iridoïede, harpagosied (HS), 8-p-kumaroïel-harpagied (8pCHG) en vog, sowel as die HS:8pCHG verhouding in Duiwelsklou is ook ondersoek. Die beweerde medisinale aktiwiteit van die knolagtige sekondêre wortels van Duiwelsklou het gelei tot 'n gevestigde uitvoermark in Duitsland, en is dus van kommersiële belang. Die stabiliteit van HS gedurende prosessering is nog nooit ondersoek nie. Die huidige studie het die invloed van drie drogingsmetodes (son-, tonnel- en vriesdroging) en drie tonneldrogingstemperature (40°C, 50°C en 60°C, droëbol temperatuur) op die HS inhoud evalueer. Metanolies ekstrakte (70% metanol-water) is met hoë-druk vloeistof chromatografie ("HPLC") geanaliseer en 'n veelvoudige ekstraksie toets (n =12) het 'n 91.70% herwinning van HS getoon. Betekenisvolle (P < 0.05) verskille is gevind tussen tonnel- en vriesdroging enersyds en sondroging andersyds, met laasgenoemde die nadeligste metode. Die vergelyking van tonneldrogingstemperature, by 'n konstante relatiewe humiditeit (RH) van 30%, het getoon dat droging by 40°C die minste HS behou het en betekenisvol (P < 0.05) verskil het van droging by 50°C. Alhoewel die droging by 60°C nie betekenisvol verskil het van die ander twee kondisies nie, het dit laer HS waardes as droging by 50°C getoon. Vriesdroging het uitstekende resultate ten opsigte van die behoud van HS gelewer (1.565% ± 0.394%; gemiddelde ± standaard afwyking), maar ekonomiese beperkings plaas noodgedwonge limiete op die toepaslikheid van hierdie drogingsmetode. Verdere studie om tonneldrogingskondisies te optimiseer word is nodig (1.526% ± 0.396%), maar veral droging by 50°C en 30% RH (1.750% ± 0.438%) het prakties aanvaarbare resultate gelewer. Toekomstige navorsing moet daarop gemik word om die spesifieke degradasie meganismes van HS gedurende die droging, vervoer en opberging van Duiwelsklouwortel te verklaar. Die NIRS ontleding van gedroogde, gemaalde Duiwelsklou wortel is vergelyk met HPLC analises van dieselfde metanolise ekstrakte wat tydens die drogingstudies gebruik is. Twee verskillende NIRS instrumente is gebruik om spektra deur diffuse weerkaatsing in die poeier te meet en kalibrasies is daaropvolgend met gedeeltelike minste vierkante ("PLS") regressie gedoen. Beide onafhanklike data stel validasie en volle kruisvalidasie is gebruik om die prestasie en voorspellingsvermoë van die onderskeie modelle te evalueer. Uitstekende voginhoud (VI) kalibrasies met 'n standaard voorspellings fout (SVF) van 0.24% (klasinterval: 2.44% tot 10.43%) en 'n korrelasie van 0.99 is gevind. Die model het goed vergelyk met die standaard laboratorium fout (SLF) van 0.14%, oor die gegewe klasinterval. Met inagneming van die sensitiwiteit van HDVC as verwysingsmetode (SLF = 0.035%), het die HS inhoud kalibrasie (klasinterval: 0.693% tot 2.244%) aanvaarbaar gepresteer met 'n SVF van 0.134%. Die beskikbare klasinterval was egter relatief klein en toekomstige NIRS studies moet gebruik maak van 'n wyer klasinterval indien moontlik. Die 8pCHG model (klasinterval: 0.069% tot 0.290%) het soortgelyk gepresteer, met 'n standaard kruisvalidasie fout van 0.028% en SLF van 0.007%. Met die insluiting van monsters van 'n tweede spesie, H. zeyheri, is beide die 8pCHG inhoud en HS:8pCHG verhouding (klasinterval: 1.84 tot 34.48) kalibrasies as moontlike metodes vir onderskeiding tussen die spesies geëvalueer. Met'n 8pCHG inhoud van ca. 0.9% het die eerste model 'n goeie skeidingsvermoë getoon. In teenstelling met vorige studies egter, het die verhoudingsmodel minder sukses getoon. Hoofkomponent analise ("PCA") van die spektra was egter baie belowend as 'n kwalitatiewe onderskeidingsmetode. Volgens hierdie studie kan NIRS 'n waardevolle tegniek wees vir die verdeling van Duiwelsklou in uitvoer klasse op grond van HS inhoud. Hierdie inhoud is egter grotendeels afhanklik van die drogingskondisies en drogingsparameters wat verder verfyn behoort te word om 'n produk van die hoogste kwaliteit met behoud van HS te verseker.

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30

MagalhÃes, Madson Linhares. "Modeling and simulation of process of drying convective using differential model diffusive - convective solved by method of numerical finite volumes." Universidade Federal do CearÃ, 2016. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16573.

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The consumption of energy is a main factor that determines the viability of any industrial process. Thermal dehydration is responsible for a high consumption of energy. In developed countries, 9 to 25% of the energy consumption of the national industry is attached to thermal dehydration. Thus, studying the dehydration process shows itself very promisor. In biological products, dehydration has a specific importance, the product conservation. The organic matter of the product and its water create a propitious medium for microorganisms proliferation that will deteriorate the product, making the product inappropriate for consumption. In this work, the modeling and simulation of a convective dehydration process using a diffusive-convective differential model solved by the finite volumes numeric method for predicting the behavior of the mean moisture content during the dehydration, defining molecular mass transfer and convective coefficients, and drawing moisture profiles of the interior of the solid. To evaluate the influence of internal and external resistances, the mass transfer Biot number was obtained. The implementation of the models of this work were made in PythonÂ using its scientific models for solving differential equations. This tool has been utilized because it is open source, has simple implementation when compared to other programming languages and has performance when performing simulations. As study of cases, experimental data of assisted convective dehydration by ultrasound of apple (Malus domestica L. var Royal Gala) cubes with 8 mm under the following operation conditions: 1, 2, 3 and 5 m/s for dehydration velocities, air flow temperature of 45ÂC and 60ÂC, presence and absence of ultrasound during the dehydration process and presence and absence of the pre-treatment with ultrasounds. The apple cubes of the experiments have 25 Â1g of mass. The dehydration has been performed until the removal of 80% of the initial mass of the cubes. The parameters, diffusivity and mass transfer coefficient, have been adjusted by Levenberg-Marquardt non-linear regression method. The results obtained in the simulations showed that the implemented model is very promisor, because it represents accurately the process. The values for diffusivity and mass transfer coefficient herein obtained were plausible. The influence of the air flow velocity, temperature and ultrasounds assistance and ultrasounds pre-treatments have been analyzed.
O consumo de energia Ã um fator determinante na viabilidade de qualquer processo industrial. A desidrataÃÃo tÃrmica Ã responsÃvel por um alto consumo de energia tÃrmica. Em paÃses desenvolvidos, o consumo da energia da indÃstria nacional Ã atribuÃdo, em mÃdia, entre 9-25% a desidrataÃÃo tÃrmica. Assim, o estudo do processo de secagem se mostra bastante promissor. Em produtos biolÃgicos, a secagem tem uma importÃncia especÃfica, a conservaÃÃo do produto, pois a matÃria orgÃnica do produto e a Ãgua presente nele torna este um local propÃcio para a proliferaÃÃo de micro-organismos que irÃo deteriorar o produto, tornando-o inapropriado para consumo. Neste trabalho, realizou-se a modelagem e simulaÃÃo do processo de secagem convectiva utilizando modelo diferencial difusivo-convectivo resolvido pelo mÃtodo numÃrico dos volumes finitos para predizer o comportamento do conteÃdo de umidade mÃdio durante a secagem de cubos, definir os coeficientes de transferÃncia de massa molecular e convectivo e encontrar os perfis do conteÃdo de umidade no interior do sÃlido. Para avaliar a influÃncia das resistÃncias interna e externa, o nÃmero de Biot de Massa foi obtido. A implementaÃÃo dos modelos deste trabalho foi realizada na ferramenta livre PythonÂ utilizando seus mÃdulos cientÃficos de resoluÃÃo de equaÃÃes diferenciais. Esta ferramenta foi utilizada porque Ã livre, implementaÃÃo simples, quando comparada com outras linguagens e possui alta performance nas simulaÃÃes. Como estudos de caso, utilizaram-se dados experimentais da secagem convectiva assistida por ultrassom de cubos de maÃÃ (Malus domestica L. var Royal Gala) com 8 mm de aresta nas seguintes condiÃÃes operacionais: velocidades de secagem: 1, 2, 3 e 5 m/s; temperatura do ar de secagem: 45 ÂC e 60 ÂC; presenÃa e ausÃncia de ultrassom durante a secagem; presenÃa e ausÃncia de etapa de prÃ-tratamento com ultrassom. Os cubos de maÃÃ dos experimentos tinham, em mÃdia, 25Â1 g. A secagem foi realizada atÃ que as amostras perdessem 80% da massa inicial. Os parÃmetros, difusividade e coeficiente de transferÃncia de massa, foram ajustados por regressÃo nÃo linear pelo mÃtodo de Levenberg-Marquardt. Os resultados obtidos nas simulaÃÃes mostraram que o modelo implementado Ã promissor, pois representa bem o processo. Os valores obtidos da difusividade e coeficiente de transferÃncia de massa foram plausÃveis. Analisou-se a influÃncia da velocidade do ar de secagem, da temperatura, da assistÃncia do ultrassom no processo e da utilizaÃÃo de uma etapa de prÃ-tratamento com ultrassom no processo de secagem.

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31

Haro, Ortega Gloria. "Numerical simulation of shallow water equations and some physical models in image processing." Doctoral thesis, Universitat Pompeu Fabra, 2005. http://hdl.handle.net/10803/7533.

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There are two main subjects in this thesis: the first one deals with the numerical simulation of shallow water equations, the other one is the resolution of some problems in image processing

The first part of this dissertation is devoted to the shallow waters. We propose a combined scheme which uses the Marquina's double flux decomposition (extended to the non homogeneous case) when adjacent states are not close and a single decomposition otherwise. This combined scheme satisfies the exact C property. Furthermore, we propose a special treatment of the numerical scheme at dry zones.

The second subject is the digital simulation of the Day for Night (or American Night in Europe). The proposed algorithm simulates a night image coming from a day image and considers some aspects of night perception. In order to simulate the loss of visual acuity we introduce a partial differential equation that simulates the spatial summation principle of the photoreceptors in the retina.

The gap restoration (inpainting) on surfaces is the object of the third part. For that, we propose some geometrical approaches based on the mean curvature. Then, we also use two interpolation methods: the resolution of the Laplace equation, and an Absolutely Minimizing Lipschitz Extension (AMLE).

Finally, we solve the restoration problem of satellite images. The variational problem that we propose manages to do irregular to regular sampling, denoising, deconvolution and zoom at the same time.
Los temas tratados en esta tesis son, por un lado, la simulación numérica de las ecuaciones de aguas someras ("shallow waters") y por otro, la resolución de algunos problemas de procesamiento de imágenes.

En la primera parte de la tesis, dedicada a las aguas someras, proponemos un esquema combinado que usa la técnica de doble descomposición de flujos de Marquina (extendida al caso no homogéneo) cuando los dos estados adyacentes no están próximos y una única descomposición en caso contrario. El esquema combinado verifica la propiedad C exacta. Por otro lado, proponemos un tratamiento especial en las zonas secas.

El segundo tema tratado es la simulación digital de la Noche Americana ("Day for Night"). El algoritmo propuesto simula una imagen nocturna a partir de una imagen diurna considerando varios aspectos de la percepción visual nocturna. Para simular la pérdida de agudeza visual se propone una ecuación en derivadas parciales que simula el principio de sumación espacial de los fotoreceptores situados en la retina.

La restauración de agujeros ("inpainting") en superficies es objeto de la tercera parte. Para ello se proponen varios enfoques geométricos basados en la curvatura media. También se utilizan dos métodos de interpolación: la resolución de la ecuación de Laplace y el método AMLE (Absolutely Minimization Lipschitz Extension).

Por último, tratamos la restauración de imágenes satelitales. El método propuesto consigue obtener una colección de muestras regulares a partir de un muestreo irregular, eliminando a la vez el ruido, deconvolucinando la imagen y haciendo un zoom.

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32

Haro, Ortega Glòria. "Numerical simulation of shallow water equations and some physical models in image processing." Doctoral thesis, Universitat Pompeu Fabra, 2005. http://hdl.handle.net/10803/7533.

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There are two main subjects in this thesis: the first one deals with the numerical simulation of shallow water equations, the other one is the resolution of some problems in image processingThe first part of this dissertation is devoted to the shallow waters. We propose a combined scheme which uses the Marquina's double flux decomposition (extended to the non homogeneous case) when adjacent states are not close and a single decomposition otherwise. This combined scheme satisfies the exact C property. Furthermore, we propose a special treatment of the numerical scheme at dry zones.The second subject is the digital simulation of the Day for Night (or American Night in Europe). The proposed algorithm simulates a night image coming from a day image and considers some aspects of night perception. In order to simulate the loss of visual acuity we introduce a partial differential equation that simulates the spatial summation principle of the photoreceptors in the retina.The gap restoration (inpainting) on surfaces is the object of the third part. For that, we propose some geometrical approaches based on the mean curvature. Then, we also use two interpolation methods: the resolution of the Laplace equation, and an Absolutely Minimizing Lipschitz Extension (AMLE). Finally, we solve the restoration problem of satellite images. The variational problem that we propose manages to do irregular to regular sampling, denoising, deconvolution and zoom at the same time.
Los temas tratados en esta tesis son, por un lado, la simulación numérica de las ecuaciones de aguas someras ("shallow waters") y por otro, la resolución de algunos problemas de procesamiento de imágenes. En la primera parte de la tesis, dedicada a las aguas someras, proponemos un esquema combinado que usa la técnica de doble descomposición de flujos de Marquina (extendida al caso no homogéneo) cuando los dos estados adyacentes no están próximos y una única descomposición en caso contrario. El esquema combinado verifica la propiedad C exacta. Por otro lado, proponemos un tratamiento especial en las zonas secas.El segundo tema tratado es la simulación digital de la Noche Americana ("Day for Night"). El algoritmo propuesto simula una imagen nocturna a partir de una imagen diurna considerando varios aspectos de la percepción visual nocturna. Para simular la pérdida de agudeza visual se propone una ecuación en derivadas parciales que simula el principio de sumación espacial de los fotoreceptores situados en la retina.La restauración de agujeros ("inpainting") en superficies es objeto de la tercera parte. Para ello se proponen varios enfoques geométricos basados en la curvatura media. También se utilizan dos métodos de interpolación: la resolución de la ecuación de Laplace y el método AMLE (Absolutely Minimization Lipschitz Extension).Por último, tratamos la restauración de imágenes satelitales. El método propuesto consigue obtener una colección de muestras regulares a partir de un muestreo irregular, eliminando a la vez el ruido, deconvolucinando la imagen y haciendo un zoom.

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33

Yucel, Orcun. "Birefringence Gradient Development During Drying of Solution Cast Functional Films and Their Mechanical, Optical and Gas Barrier Properties." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1377699282.

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34

Turan, Umut. "Simulation Of A Batch Dryer By The Finite Difference Method." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606478/index.pdf.

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The objectives of this study are to investigate the dynamic behavior of an apple slab subjected to drying at constant external conditions and under changing in the drying temperatures and to determine the effects of temperature and time combinations at different steps during drying on the process dynamics parameters, time constant and process gain of the system. For this purpose, a semi-batch dryer system was simulated by using integral method of analysis. Initially, the dynamic behavior of the drying temperature was investigated by using first order system dynamic model. Process dynamic parameters, time constant and process gain of the system, for change in drying temperature were determined. Secondly, investigation of the drying kinetics of the apple slab was carried out under constant external conditions in a semi-batch dryer. A mathematical model for diffusion mechanism assumed in one dimensional transient analysis of moisture distribution was solved by using explicit finite difference method of analysis. Thirdly, investigation of the drying kinetics of the apple slab was carried out under change in drying temperature at different time steps during drying. Inverse response system model was used for the representation of the dynamic behavior of drying. Process dynamic parameters, time constant and process gain of the system were determined. Model predicted results for apple slab drying under constant external condition and under step change in the drying temperature were compared with the experimental data.

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35

Jaafari, Chaimaa. "Effect of early age drying shrinkage on the seismic response of RC Structures." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI113.

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Les structures en béton armé s'endommagent au cours de leur vie à cause de plusieurs facteurs : conditions thermiques, attaques chimiques, retrait, fluage, carbonatation, corrosion, etc. Ce processus d'endommagement débute dès les premiers jours de la vie de l'ouvrage et continue lors de son vieillissement. L'endommagement au jeune âge peut influencer significativement le comportement dynamique des structures en béton armé. En effet, la fréquence propre d'une structure, qui constitue un paramètre de dimensionnement, peut être fortement réduite à cause de cet endommagement. Afin de déterminer l'influence de l'endommagement dû aux effets du jeûne âge (0 à 28 jours) sur la réponse sismique d'une structure en béton armé, ce travail de thèse a combiné à la fois modélisations numériques et essais pseudo-dynamiques sur deux groupes de portiques en béton armé. Le premier groupe a été gardé en conditions endogènes (échanges hydriques avec l'extérieur empêchés) durant le jeune âge afin de limiter les effets du retrait de séchage (fissuration). Le second groupe a quant à lui été gardé en conditions non-endogènes (échange d'eau avec le milieu extérieur possible) similaires aux conditions de chantier, ce qui a induit un endommagement initial (fissurations) dû notamment à un retrait de séchage plus important. Les deux types de portiques ont été soumis à la fin de leur jeune âge au même chargement sismique au moyen d'essais pseudo-dynamiques. D'une part, ce manuscrit présente les résultats expérimentaux obtenus à travers la réalisation d'essais pseudo-dynamiques afin d'évaluer le comportement dynamique des portiques face à un séisme d'intensité modérée. Les structures ont été instrumentées en utilisant de la fibre optique, des capteurs de déplacement et de force ainsi que des vélocimètres et de la corrélation d'image. D'autre part, le modèle numérique en poutres multifibres qui a été développé pour les portiques et qui permet de suivre l'évolution de leur endommagement au jeune âge et de déterminer leur réponse lorsqu'ils sont soumis à un accident sismique est présenté. Dans ce modèle numérique, le retrait et les déformations thermiques du béton sont calculés avant d'être réinjectés dans un modèle d'endommagement couplé permettant de tenir compte des effets de fluage et de déformations mécaniques. Le modèle numérique a été validé en comparant ses résultats à ceux obtenus expérimentalement, ce qui a permis d'évaluer l'évolution de fréquences propres des deux types de structures au jeune âge ainsi que de quantifier leur différence de comportement dans le domaine non-linéaire. Les travaux menés dans le cadre de cette thèse ont donc permis de proposer un modèle complet pour les structures en béton armé qui peut être utilisé afin de suivre l'évolution de leur endommagement allant de leur réalisation à l'application d'un accident sismique et de quantifier leur vulnérabilité sismique
Reinforced Concrete (RC) structures get damaged over time due to many factors: thermal conditions, chemical attacks, shrinkage, creep, carbonation, corrosion, etc. This damaging process starts at early-age and continues with structure aging. Early age damage can have a significant impact on the dynamic behavior of reinforced concrete structures. In fact, the natural frequency of a structure, which is a design parameter can be highly reduced due to this damage. In order to quantify the impact of early-age damage (0 to 28 days) on the seismic response of a reinforced concrete structure, this thesis combined both numerical modeling and pseudo-dynamic tests on two types of RC portal frames. The first one was kept in endogenous conditions (water exchange with the surrounding environment was prevented) during its early age period in a way to limit drying effects leading to cracks. As for the second one, it was kept in non-endogenous conditions (possibility of water exchange with the surrounding environment) similar to construction site conditions, which induced an initial damage (cracks apparition) due to a more important drying shrinkage. Both types of RC portal frames were subjected after their early age period to the same seismic loading using pseudodynamic tests. On the one hand, this manuscript presents the experimental results obtained through the use of pseudodynamic tests in order to evaluate the behavior of the two types of RC structures under a moderate intensity earthquake. The structures were instrumented using optical fiber sensors, displacement and load sensors, velocimeters and monitored using Digital Image Correlation. On the other hand, the enhanced multifiber beam model that was developed for the portal frames in order to follow their early age damage and to determine their static and dynamic behavior while accounting for their early age effects is presented. In this numerical model, shrinkage and concrete thermal deformations are calculated and then introduced as inputs of a coupled damage model accounting for creep and mechanical deformations. Such model was validated by comparing its results to the ones obtained experimentally, which made it possible to evaluate the evolution of frequency content of the two types of structures during early age and to quantify their difference of behavior in the non-linear domain. Work conducted within this thesis thus allowed proposing a complete model for reinforced concrete structures that can be used in order to follow their damage evolution from casting until being subjected to a seismic load and to quantify their seismic vulnerability

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Mostert, ME, BM Botha, Plessis LM Du, and KG Duodu. "Short Communication Effect of fruit ripeness and method of fruit drying on the extractability of avocado oil with hexane and supercritical carbon dioxide." Society of Chemical Industry, 2007. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000806.

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Background: Oil yield from avocado fruit may be influenced by fruit pre-treatment and extraction method. Unripe and ripe avocado fruit pieces were deep-frozen at −20 ◦C and either freeze-dried or oven-dried (80 ◦C). Oil yield from these samples was determined after extraction with hexane and supercritical carbon dioxide (SC-CO2). The fruit samples were examined using scanning electron microscopy before and after oil extraction. RESULTS: Average oil yield from ripe fruit (freeze-dried and oven-dried combined) was 72 g kg−1 higher than from unripe fruit for SC-CO2 extracts and 61 g kg−1 higher for hexane extracts. This may be due to enzymatic degradation of parenchyma cell walls during ripening, thus making the oil more available for extraction. Freezedried samples had a mean oil yield 55 g kg−1 greater than oven-dried samples for SC-CO2 extracts and 31 g kg−1 higher for hexane extracts. However, oil yields from ripe fruit (freeze-dried and oven-dried) subjected to hexane extraction were not significantly different. All hexane extracts combined had a mean oil yield 93 g kg−1 higher than SC-CO2 extracts. CONCLUSION: SC-CO2 may be more selective and may create paths of least resistance through the plant material. Hexane, on the other hand, is less selective and permeates the whole plant material, leading to more complete extraction and higher oil yields under the experimental conditions.

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Friberg, Rasmus. "A new measurement method to analyse the thermochemical conversion of solid fuels." Doctoral thesis, KTH, Materials Science and Engineering, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3014.

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The firing of fuel wood has been identified as one of themain causes of pollutant emissions from small-scale (<100kW) combustion of wood fuels. The emissions are a result ofinsufficient combustion efficiency. This thesis presents a newmeasurement method to analyse the thermochemical conversion ofbiofuels in general, as well as to explain the main reason ofthe inefficient combustion of fuel wood in particular.

In general, small-scale combustion of biofuels are carriedout by means of packed-bed combustion (PBC)technology. Acomprehensive literature review revealed that textbooks,theories, and methods in the field of thermochemical conversionof solid fuels in the context of PBC are scarce. This authorneeded a theoretical platform for systematic research on PBC ofbiofuels. Consequently, a new system theory - the three-stepmodel - was developed, describing the objectives of, theefficiencies of, and the process flows between, the leastcommon functions (subsystems) of a PBC system. The three stepsare referred to as the conversion system, the combustionsystem, and the heat exchanger system (boiler system). A numberof quantities and concepts, such as solid-fuel convertibles,conversion gas, conversion efficiency, and combustionefficiency, are deduced in the context of the three-step model.Based on the three-step model a measurement method washypothetically modelled aiming at the central physicalquantities of the conversion system, that is, the mass flow andstoichiometry of conversion gas, as well as the air factor ofthe conversion system. An uncertainty propagation analysis ofthe constitutive mathematical models of the method was carriedout. It indicated that it should be possible to determine themass flow and stoichiometry of conversion gas within the rangesof relative uncertainties of ±5% and ±7%,respectively. An experimental PBC system was constructed,according to the criteria defined by the hypothetical method.Finally, the method was verified with respect to total massflow of conversion gas in good agreement with the verificationmethod. The relative error of mass flow of conversion gas wasin the range of ±5% of the actual value predicted by theverification method.

One experimental series was conducted applying the newmeasurement method. The studied conversion concept correspondedto overfired, updraft, horizontal fixed grate, and verticalcylindrical batch reactor. The measurements revealed newinformation on the similarities and the differences in theconversion behaviour of wood chips, wood pellets, and fuelwood. The course of a batch conversion has proven to be highlydynamic and stochastic. The dynamic range of the air factor ofthe conversion system during a run was 10:1. The empiricalstoichiometry of conversion gas during a run was CH_3.1O:CH₀O₀. Finally ,this experimental series revealed one ofthe main reasons why fuel wood is more difficult to burn thanfor example wood pellets. The relatively dry fuel wood (12-31g/m₂,s) displayed a significantly lower time-integratedmean of mass flux of conversion gas than both the wood pellets(37-62 g/m₂,s) and the wood chips (50-90 g/m₂,s). The higher the mass flux of conversion gasproduced in the conversion system, the higher the combustiontemperature for a given combustion system, which in turn ispositively coupled to the combustion efficiency.

In future work the method will be improved so thatmeasurements of combustion efficiency can be carried out. Othertypes of conversion concepts will be studied by the method.

Keywords: Packed-bed combustion, thermochemical conversionof biomass, solid-fuel combustion, fuel-bed combustion, gratecombustion, biomass combustion, gasification, pyrolysis,drying.

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Liu, Xin. "Numerical Modelling of Shallow Water Flows over Mobile Beds." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35131.

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This Ph.D. thesis aims to develop numerical models for two-dimensional and three-dimensional shallow water systems over mobile beds. In order to accomplish the goal of this dissertation, the following sub-projects are defined and completed. 1: The first sub-project consists in developing a robust two-dimensional coupled numerical model based on an unstructured mesh, which can simulate rapidly varying flows over an erodible bed involving wet–dry fronts that is a complex yet practically important problem. In this task, the central-upwind scheme is extended to simulation of bed erosion and sediment transport, a modified shallow water system is adopted to improve the model, a wetting and drying scheme is proposed for tracking wet-dry interfaces and stably predict the bed erosion near wet-dry area. The shallow water, sediment transport and bed evolution equations are coupled in the governing system. The proposed model can efficiently track wetting and drying interfaces while preserving stability in simulating the bed erosion near the wet-dry fronts. The additional terms in shallow water equations can improve the accuracy of the simulation when intense sediment-exchange exists; the central-upwind method adopted in the current study shows great accuracy and efficiency compared with other popular solvers; the developed model is robust, efficient and accurate in dealing with various challenging cases. 2: The second sub-project consists in developing a novel numerical scheme for a coupled two-dimensional hyperbolic system consisting of the shallow water equations with friction terms coupled with the equations modeling the sediment transport and bed evolution. The resulting 5*5 hyperbolic system of balance laws is numerically solved using a Godunov-type central-upwind scheme on a triangular grid. A spatially second-order and temporally third-order central-upwind scheme has been derived to discretize the conservative hyperbolic sub-system. However, such schemes need a correct evaluation of local wave speeds to avoid instabilities. To address such an issue, a mathematical result by the Lagrange theorem is used in the proposed scheme. Consequently, a computationally expensive process of finding all of the eigenvalues of the Jacobian matrices is avoided: The upper/lower bounds on the largest/smallest local speeds of propagation are estimated using the Lagrange theorem. In addition, a special discretization of the bed-slope term is proposed to guarantee the well-balanced property of the designed scheme. 3: The third sub-project consists in designing a novel scheme to estimate bed-load fluxes which can produce more accurate results than the previously reported coupled model. Using a pair of local wave speeds different from those used for the flow, a novel wave estimator in conjunction with the central upwind method is proposed and successfully applied to the coupled water-sediment system involving a rapid bed-erosion process. It was demonstrated that, in comparison with the decoupled model, applying the proposed novel scheme to approximate the bed-load fluxes can successfully avoid the numerical oscillations caused by simple and less stable schemes, e.g. simple upwind methods; in comparison with the coupled model using same flux-estimator for both hydrodynamic and morphological systems, the proposed numerical scheme successfully prevents excessive numerical diffusion for prediction of bed evolution. Consequently, the proposed scheme has advantages in terms of accuracy which are shown in several numerical tests. In addition, analytical expressions have been provided for calculating the eigenvalues of the coupled shallow-water-Exner system, which greatly enhances the efficiency of the proposed method. 4: The fourth sub-project consists in developing a three-dimensional numerical model for the simulation of unsteady non-hydrostatic shallow water flows on unstructured grids using the finite volume method. The free surface variations are modeled by a characteristics-based scheme which simulates sub- and super-critical flows. Three-dimensional velocity components are considered in a collocated arrangement with a sigma coordinate system. A special treatment of the pressure term is developed to avoid the water surface oscillations. Convective and diffusive terms are approximated explicitly, and an implicit discretization is used for the pressure term. The unstructured grid in the horizontal direction and the sigma coordinate in the vertical direction facilitate the use of the model in complicated geometries. 5: The fifth sub-project consists in developing a well-balanced three-dimensional shallow water model which is able to simulate shock waves over dry bed. Due to the hydrostatic simplification of the vertical momentum equation, the governing system of equations is not hyperbolic and can not be solved using standard hyperbolic solvers. That is, one can not use a high-order Godunov-type scheme to compute all fluxes through cell-interfaces. This may cause the model to fail in simulations of some unsteady-flows with discontinuities, e.g., dam-break flows and floods. To overcome this difficulty, a novel numerical scheme for the three-dimensional shallow water equations is proposed using a relaxation approach in order to convert the system to a hyperbolic one. Thus, a high-order Godunov-type central-upwind scheme based on the finite volume method can be applied to approximate the numerical fluxes. The proposed model can also preserve the ``lake at rest'' state and positivity of water depth over irregular bottom topographies based on special reconstruction of the corresponding parameters. 6: The sixth sub-project consists in extending the result of the fifth sub-project to development of a three-dimensional numerical model for shallow water flows over mobile beds, which is able to simulate morphological evolutions under shock waves, e.g. dam-break flows. The hydrodynamic model solves the three-dimensional shallow water equations using a finite volume method on prismatic cells in sigma coordinates based on the scheme prposed in sub-project 5. The morphodynamic model solves an Exner equation consisting of bed-load sediment transportation. The performance of the proposed model has been demonstrated by several laboratory experiments of dam-break flows over mobile beds.

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Silva, Cristiane Kelly Ferreira da. "Estimação de Parâmetros de Secagem de Alimentos- Formulação de Luikov e uso da Transformada Integral Generalizada." Universidade Federal da Paraíba, 2010. http://tede.biblioteca.ufpb.br:8080/handle/tede/5414.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Drying is one of the most widely used commercial processes for the preservation of agricultural products, whose maximum objective is to maintain its qualities. On the other hand, for the optimal design and control of processes and equipments it is necessary a clear understanding of the involved phenomena and the transport properties of the product being handled. In this sense two mathematical models were developed, in the configuration of an infinite plane plate, with the aim of studying the process of drying food. The first model was based on Fick's second law, to model the process of mass transfer, treated by the Classical Integral Transform Technique (CITT). The second model was developed for the analysis of the simultaneous heat and mass transfer using the equations of Luikov, where the distributions of temperature and moisture content inside the food were obtained following the formalism inherent to the Generalized Integral Transform Technique (GITT). In both models, the thermophysical properties are considered constant. The results obtained in the two models were compared and found that they are able to describe the process of drying food. The influence of thermophysical parameters relating to the simultaneous heat and mass transfer was also analyzed. The accuracy of the calculations of a heat and mass balance depends on the precision as that is known the properties of the product and the choice of reliable data for these properties is an important part to any careful analysis engineering. Thus, an inverse problem of parameters estimation, for the mass transfer, was solved through the Levenberg-Marquardt's minimization algorithm. The results obtained through the solution of the inverse problem for the effective mass diffusivity are the same order magnitude of those reported in the literature. Key words - food drying, Fick law, Luikov, GITT, inverse method.
A secagem é um dos processos comerciais mais usados na conservação de produtos agropecuários, cujo objetivo máximo é a manutenção de suas qualidades. Por outro lado, para o dimensionamento e controle ótimos dos processos e dos equipamentos é necessário um claro entendimento dos fenômenos envolvidos e das propriedades de transporte do produto que está sendo manuseado. Neste sentido, foram desenvolvidos dois modelos matemáticos, na configuração de uma placa plana infinita, com o objetivo de se estudar o processo de secagem de alimentos. O primeiro modelo foi baseado na segunda lei de Fick, para modelar o processo de transferência de massa, tratado através da Técnica da Transformada Integral Clássica (CITT). O segundo modelo foi desenvolvido para a análise da transferência simultânea de calor e massa usando-se as equações de Luikov, onde as distribuições de temperatura e teor de umidade no interior do alimento foram obtidas segundo os formalismos inerentes à Técnica da Transformada Integral Generalizada (GITT). Em ambos os modelos as propriedades termofísicas são consideradas constantes. Os resultados obtidos nos dois modelos foram comparados e constatou-se que os mesmos são capazes de descrever o processo de secagem de alimentos. Avaliou-se também a influência dos parâmetros termofísicos referentes à transferência simultânea de calor e massa. A exatidão dos cálculos de um balanço de calor e massa depende da precisão com que se conhecem as propriedades do produto e, a escolha de dados confiáveis dessas propriedades é uma parcela importante para qualquer análise cuidadosa de engenharia. Desta forma, um problema inverso de estimação de parâmetros, para a transferência de massa, foi resolvido através do algoritmo de minimização de Levenberg-Marquardt. Os resultados obtidos através da solução do problema inverso para a difusividade efetiva de massa são da mesma ordem de grandeza dos reportados na literatura.

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Himeda, Makhlouf. "Propriétés physico-chimiques et rhéologiques de la farine et de l'amidon de taro (Colocasia esculenta L. Schott) variété Sosso du Tchad en fonction de la maturité et du mode de séchage." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0262/document.

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Les résultats montrent que la teneur en cendres, protéines brutes, sucres disponibles, oxalates totaux, amidons et phosphore augmente significativement (p<0,05) avec la maturité. En revanche la teneur en amylose baisse avec la maturité. La capacité d'absorption d'eau, l'indice de solubilité, la température et l'enthalpie de gélatinisation (delta H) des farines et amidons augmentent significativement (p<0,05) en fonction du degré de maturité. Quel que soit le degré de maturité, les granules d'amidon ont présenté un diffractogramme caractéristique de type "A". Les précurseurs de brunissement augmentent significativement (p<0,05) avec le degré de maturité. Le paramètre L* des farines et des pâtes augmente alors que a* diminue en fonction du degré de maturité. Le paramètre L* est plus élevé et a* moins élevé dans le cas du séchage électrique que le séchage solaire. Les caractéristiques sensorielles des pâtes de taro Sosso sont affectées positivement par le degré de maturité et le séchage électrique. L'acceptabilité générale des pâtes de taro Sosso est corrélée à la couleur de celles-ci. Cette étude suggère que 10 mois de maturité de taro Sosso et le séchage électrique (40°C) sont des conditions favorables à l'obtention des pâtes de qualité acceptable
Results showed that the ash content, crude proteins, available sugars, total oxalate, starch and phosphorus content increased significantly with the maturity stage. On the other hand the amylose content decreased as function of the maturity. The water adsorption capacity, the water solubility index, the temperature and the enthalpy of gelatinization of the flour and starch increased significantly with the maturity stage. Irrespective of the degree of maturity the starch granules diffractogramm were exhibited an "A" type cristallinity. The browning indicators increased significantly (p<0.05) with the maturity stage of the tuber. The color coordinate L* of the flours and that of its dough increased while a* decreased with the maturity stage. These two coordinates lend themselves better with electric drying than solar drying. The sensory characteristics of the taro Sosso dough were positively affected by the maturity stage and electric drying. The overall acceptability of taro Sosso dough was correlated with its color. These results suggest that 10 months of the taro Sosso maturity and the electric drying (40°C) are the best conditions to obtain the acceptable pastes. These optimum conditions might be used to produce the taro flour at industrial scale

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Schiavon, Rafael de Almeida. "Efeitos do médtodo de secagem sobre a qualidade e o desempenho industrial de grãos de arroz armazenados em ambiente controlado com temperatura reduzida." Universidade Federal de Pelotas, 2010. http://repositorio.ufpel.edu.br/handle/ri/1337.

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We studied effects of the drying system and the storage time at low temperature, with evaluation of industrial performance and quality parameters conservability consumption in rice grains harvested with moisture content around 20% and dried up to 13% by three methods drying: (a) classic intermittent, (b) intermittently scaled and (c) by dry-airing. Going to make use of the pilot scale equipment in a laboratory scale, equipped with electric heaters to heat the air, was operated in order to obtain drying grain according to the method. In the classic intermittent air temperature had increased from 70+5ºC, 90+5ºC e 100+5ºC, respectively in the 1st, 2nd and 3rd hours until the penultimate, with a gradual reduction temperature in the last minute. In method intermittent scaled, with the same thermal management of method intermittent air classic, the operation took place in two stages: the first by 15-16% humidity, and the second supplementary drying, after 30 days of the first stage, the grain stored under cooling. In the third method, dry-airing, the first step was made in column dryer with air at 100°C in the two chambers and the grains were removed with 15-16% humidity and transferred to a silo dryer and rested for six hours before turning on the aeration with ambient air to supplement the drying. Once dried, the grains were stored at room temperature reduced to 17 ° C. In the first and twelfth months of storage were evaluated humidity, volume and weight of thousand grains, whole grain yield, incidence of defects, Texture profile, profile branquimétrico and cooking parameters in grains by conventional processes and parboiled. Was also studied consumer preference insect Sitophilus sp in paddy, full and white, putting - 12 - them in an arena and being evaluated after 60 days with counts of insects and consumption. It was concluded that: (1) drying methods intermittent fever, intermittent and staggered by drought-airing show similarities in the effects of physical parameters, performance industrial and cooking, both for industrialization by the conventional process like white rice by parboiling; (2) the parboiling and increased storage time cause increased incidence of grains with defects in the acidity of the oil and color in rice, irrespective of drying method used, (3) Texture parameters are affected by the ongoing storage and by the industrialization process, regardless of drying method, (4) storage in an environment with low temperatures preserves the quality of rice for at least a year, (5) the insect Sitophilus sp. has greater preference for their reproduction and consumption of grains of rice than the grain shell and polished grains, in that order.
Foram estudados efeitos do sistema de secagem e do tempo de armazenamento em temperatura reduzida, com avaliação de desempenho industrial, parâmetros de conservabilidade e qualidade de consumo, em grãos de arroz colhidos com umidade próxima a 20% e secados até 13%, em três métodos de secagem: (a) intermitente clássico, (b), intermitente escalonado e (c) por seca-aeração. Foi utilizado equipamento piloto, em escala laboratorial, dotado de resistências elétricas para o aquecimento do ar, possibilitando sua operação de forma a se obter secagem dos grãos conforme o método. No intermitente clássico, o ar teve temperaturas crescentes de 70+5ºC, 90+5ºC e 100+5ºC, respectivamente na 1ª, 2ª e da 3ª até a penúltima hora, havendo redução gradual da temperatura na última hora. No método intermitente escalonado, com o mesmo manejo térmico do ar do método intermitente clássico, a operação ocorreu em duas etapas: a primeira até 15 a 16% de umidade, e a segunda, secagem complementar, após 30 dias da primeira etapa, com os grãos armazenados sob resfriamento. No terceiro método, de seca-aeração, a primeira etapa foi realizada em secador de coluna com ar a 100°C nas duas câmaras e os grãos serem retirados com 15-16% de umidade e transferidos para um silo secador, ficando em repouso por 6 horas antes de ligar a aeração com ar ambiente para complementar a secagem. Depois de secados, os grãos foram armazenados em ambiente com temperatura reduzida para 17ºC. No primeiro e no décimo segundo meses de armazenamento foram avaliados umidade, peso volumétrico, peso de mil - 10 - grãos, rendimento de grãos inteiros, incidência de defeitos, perfil texturométrico, perfil branquimétrico, e parâmetros de cocção, em grãos beneficiados pelos processos convencional e parboilizado. Foi também estudada a preferência de consumo do inseto Sitophilus sp em arroz com casca, integral e branco, colocando os mesmos em uma arena e sendo avaliado após 60 dias com contagem de insetos e consumos. Concluiu-se que: (1) os métodos de secagem intermitente clássica, intermitente escalonada e por seca-aeração apresentam similaridades de efeitos nos parâmetros físicos, de desempenho industrial e de cocção, tanto para industrialização por processo convencional de arroz branco como por parboilização; (2) a parboilização e o aumento do tempo de armazenamento provocam intensificação na incidência de grãos com defeitos, na acidez do óleo e na coloração no arroz, independentemente do método de secagem utilizado; (3) os parâmetros texturométricos são afetados pelo decorrer de armazenamento e pelo processo de industrialização, independentemente do método de secagem; (4) o armazenamento em ambiente com temperaturas reduzidas preserva a qualidade do arroz por pelo menos um ano; (5) o inseto Sitophilus sp. tem maior preferência para sua reprodução e pelo consumo de grãos de arroz integral do que pelos grãos com casca e grãos polidos, nesta ordem.

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Reyes, Torres Maria Del C. "Water Management Efficiency in the Food and Beverage Industry." ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/2298.

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Water is critical for food production, food security, and health. Water quality management influences freshwater sustainability, land, and energy administration. Global agriculture accounts for more than 70% of all water consumption; the fertilizer, manure, and pesticide overspills are chief sources of water pollution worldwide. On a global scale, food-related waste directly impacts local food production and water resource management. The purpose of this multiple-case study on the food and beverage (FB) industry in the State of Georgia was to identify successful strategies for improving water management efficiency. The concepts of systems thinking, adaptive resource management, and integrated water resource management provided the conceptual framework for the study. Data were collected via personal interviews with 2 global supply chain leaders in the FB industry and 1 water expert in the public water utility system in Georgia. The findings showed 10 themes: sustainability; mission-driven culture; ethical responsibility; water quality and governance; food safety and sanitation; water conservation and climatic trends; waste management; nutrition and the freeze drying method; knowledge sharing and collaboration; and water detention and retention systems. The study results are intended to contribute to social change by providing information to global supply chain leaders, policy makers, entrepreneurs, and sustainability leaders to implement sustainability beyond the environmental value; these findings will also help achieve a positive posture on resource overconsumption and waste management for efficient and complex decision making within a worldwide spectrum.

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Toigo, Rúbia Lazzaretti Pereira. "Desenvolvimento e controle de qualidade de forma farmacêutica pó para inalação contendo levodopa." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/132911.

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O presente trabalho visa desenvolver micropartículas na forma farmacêutica pó inalatório contendo levodopa, um fármaco empregado no tratamento da doença de Parkinson. As micropartículas foram preparadas pela técnica de secagem por aspersão utilizando os polímeros ácido hialurônico, quitosana e hidroxipropilmetilcelulose. Desenvolveu-se método analítico indicativo de estabilidade por cromatografia líquida de alta eficiência (CLAE) para o controle de qualidade da formulação, bem como, estudos preliminares de estabilidade e determinação da cinética de fotodegradação. Utilizou-se coluna analítica ACE® RP-18 com tampão fosfato monobásico 0,01 M, ajustado a pH 3,0 como fase móvel, com vazão de 1,0 mL/min e detecção em 280 nm. A linearidade foi obtida na faixa de concentração de 10-60 μg/mL (r2=0,9999) (α=5%). Os limites de quantificação e detecção foram 208 ng/mL e 46,8 ng/mL, respectivamente. Os excipientes e produtos de degradação não apresentaram interferência na eluição da levodopa. Resultados adequados foram encontrados para repetibilidade, precisão intermediária (<2% DPR), exatidão e robustez. Os resultados de recuperação estiveram na faixa de 100,01% a 100,93%. A cinética de fotodegradação em solução frente à luz UVC indicou reação de segunda ordem. A caracterização da formulação demonstrou resultados satisfatórios em relação ao teor, diâmetro aerodinâmico, densidade, teor de umidade e morfologia. A formulação apresentou tamanho de partícula inferior a 16,2 μm e formato arredondado com estrutura oca. A densidade de compactação mostrou valores entre 0,06-0,08 g/cm3 e diâmetro aerodinâmico abaixo de 5 μm, sugerindo que os pós são apropriados para a deposição nas regiões mais profundas do pulmão. Além disso, realizou-se estudo de citotoxicidade pulmonar in vivo, o qual demostrou que a administração intratraqueal das micropartículas não induziu aumentos significativos dos indicadores de toxicidade pulmonar, em comparação ao grupo controle-positivo. Portanto, a avaliação da toxicidade aguda sugere que a liberação pulmonar de levodopa pode ser uma nova e promissora via de administração para este fármaco.
The aim of this study was to develop microparticles containing levodopa for pulmonary delivery, a drug used in the treatment of Parkinson´s disease. The microparticles were prepared by spray-drying using the polymers hyaluronic acid, chitosan and hydroxypropyl methylcellulose. A stability-indicating method was developed and validated for quality control by high performance liquid chromatography (HPLC), as well as, stability studies and photodegradation kinetics. The analytical column ACE® RP-18 was operated with 0.01 M monobasic potassium phosphate, adjusted to a pH value 3.0 as mobile phase, at a flow rate of 1.0 mL/min with detection wavelength at 280 nm. Linearity was obtained over the concentration range of 10-60 μg/mL (r2=0.9999) (α=5%). The quantification limit and detection limit were 208 ng/mL and 46.8 ng/mL, respectively. Excipient ingredients and resulting degradation products had no interference in the levodopa elution. Adequate results were found for repeatability, inter-day precision (<2% RSD), accuracy and robustness. The recovery results were in the range of 100.01% to 100.93%. The photodegradation kinetics in solution front to UVC light indicated the second-order reaction. The formulation showed satisfactory results for drug content, aerodynamic diameter, density, water content and morphology. The formulation presented particle size below 16.2 μm and spherical shape presenting a hollow structure. The tapped density ranged from 0.06-0.08 g/cm3 and an aerodynamic diameter smaller than 5 μm, suggesting that the powders are appropriated for deep lung deposition. Besides that, a cytotoxicity study in vivo was performed which showed that microparticles intratracheal administration did not induce significant increases of lung toxicity indicators compared with the positive control. Therefore, the acute lung toxicity evaluation suggests that pulmonary levodopa delivery could be a new and promising administration route for this drug.

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44

Grouhel, Marie-Christine. "Evolution de l'etat hygrothermique d'un toit experimental de tuiles de terre cuite durant son sechage." Paris 6, 1988. http://www.theses.fr/1988PA066273.

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La determination de l'evolution de l'etat hygrothermique d'un toit experimental de tuiles de terre cuite durant son sechage est effectuee a partir du modele mathematique de luikov et des equations des conditions aux limites de type fourier. On determine les coefficients thermophysiques et de transfert de masse de la terre cuite. Les coefficients de transferts de chaleur et de masse, dus a la convection en surface et en sous-face de la couverture, sont etudies en fonction des donnees meteorologiques. La resolution numerique du probleme de sechage suppose unidimensionnel est effectuee par une methode de differences finies

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45

Theerakulpisut, Somnuk. "Modelling heat pump grain drying systems." 1990. http://repository.unimelb.edu.au/10187/2835.

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Drying is a common process in a number of industries. Products such as furs, wools, textiles, clay, timber, grains, fruits, and vegetables, at some stage, require drying. Review of the literature reveals that commercial dryers are highly inefficient due to various factors. One such factor is that commercial dryers are generally not equipped with heat recovery facilities. Heat pumps can provide a very efficient means of recovering both sensible and latent heat, hence energy loss can be substantially reduced. Furthermore, a heat pump always delivers more heat than the work input to the compressor. These two salient features render heat pump drying a premium alternative for efficient use and conservation of energy in drying industries.

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46

Wu, Hao, and 吳浩. "Influence of Drying Methods on the Quality of Pickled-Pineapple." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/90834151552166357648.

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碩士
國立屏東技術學院
食品技術研究所
85
Pineapples, due to its oversupply to the market in recent years,were processedby pickling to lengthen the storage period and enhance its added-value. The experiment was aimed to find the optimal drying method for controlling the sucrose in dried pickled-pineapple to be in crystalline state. Three differentkinds of method including freezing-dried, air dried (rapid dried) and cold air-dried (slow dried) were investigated. Physical properties such as water absorption ,drying rate, rehydration and color, were measured to evaluate the influences of drying methods on the qualities of dried pineapple. It was found that pickled-pineapple dried with cold air processes lower moisture absorption capability as compared to those of Freeze- dried products. The sucrose in cold air-dried samples of the pickled-pineapple become crystalline state and loweredthe product''s moisture absorption. Cold air-dried method not only stabilize the quality of product during storage,but also lengthen the shelf-life of dried pickle-pineapple.The sucrose in both pickle-pineapple and cold air-dried pickledwere found to be in crystalline state rather than amorphorus,thus lowered themoisture absorption capability.

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47

Chiu, Chi-fang, and 邱祺方. "Evaluating Drying Methods for Archaeological Antler Using Artificially Degraded Samples." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/11516532344929978681.

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碩士
雲林科技大學
文化資產維護系碩士班
98
In ancient Taiwan, there were large amounts of deer. The quantity of antler and deer bone remains should be large. In some of Taiwan’s archaeological sites, some everyday tools made from antler have been found. Also, in some Taiwan aborigine tribes, we can find some antler utensils and artifacts. In order to conserve antler artifacts well, it is essential to understand the character of antler, and different conservation approaches for antler. Therefore, the use of antler artifacts in Taiwan was investigated and the different dehydration approaches and conservation methods for antler /bone at home and abroad through documents and literature. The weather in Taiwan is always quite humid and warm. Skeletal materials degrade quickly in the soil and are left very fragile, but they can usually be dried in air quite safely. In contrast, skeletal materials from permanently wet soil are better preserved but can be damaged during the drying process. Hence, this research is focus on the dehydration approach of the waterlogged antler. Because archaeological antler were rare, it is not acceptable to use real finds to do any tests. Therefore, we adopted the present antler of Formosan sika deer, Formosan sambhar, moose and white-tail deer to do artificial degradation testing by aging 50oC in an oven for 28 days. Then, we chose to dry the samples from 100% acetone or 20% glycerol. After 7 days of bathing in the reagents, we measured the Young’s modulus to compare the effects of dehydration. The results of the experiment are summarized below: 1.After the degradation, the outward appearance of the antler compact tissue turned darker, but the structure still looked intact. After the dehydration, the outward appearance of the antler compact tissue was better and in a more stable condition. As to the antler spongy tissue, after the degradation, they had turned into a fragile condition and darker. After bathing in either glycerol or acetone for 7 days, the condition of the antler spongy tissue became more stable and the color was lighter than before dehydration. 2.The result of the experiment suggested that glycerol could provide the same effect of the dehydration as acetone, in some antler samples glycerol did better than acetone. The glycerol could be an alternative better choice from acetone because it does not cause the health/fire hazards, and there are no solvents to remove fats, oils and other evidence from the bone/antler. Therefore, we suggest that glycerol could be a good choice of the antler dehydration. 3.In this experiment, we also found that due to the different result of the spongy and compact bone, we need to do more conservation approach on the feeble spongy bone.

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48

Chou, Hung Pin, and 周弘斌. "Development of papaya milk powder and flavor additives by different drying methods." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/06496641513430866380.

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碩士
大葉大學
食品工程研究所
88
The objects of this study were to use different methods, including hot air, spray and vacuum drying, to prepare powders of papaya milk powder. The effect of different processing conditions on the properties of the papaya milk powder was investigated in the study as well. Before drying processes, papaya juice was blanched by microwave mechanism for six minutes. Then pectinase was added into the treated papaya juice which has been incubated at 50 ℃ for 120 minutes. Finally, milk powder and adjunct were added into papaya juice before drying process. The temperature used for hot-air and vacuum drying were 50, 60 and 70 ℃. The solid contents were controlled on 30%. Monolayer moisture contents of dehydrated products after vacuum drying and hot air drying were obtained by using the regression of BET model. The results showed that when papaya milk were treated at 60 ℃, the powder was whiter, the main range was between 0.125 and 0.25 mm, solubility was higher, flowability and bulk density were 1.51 g/sec and 0.46 g/ml, but both flowability and bulk density were lower compared with other samples. However, the sensory evaluation showed that no significant difference was found among the samples treated with various conditions. The optimum drying adjunct was maltodextrin, and the combination of 20% papaya juice, 10% milk powder, and 10% maltodextrin was best formula for sensory evaluation. Before the solid contents were controlled on 30% to receive the best outlet temperature, feeding rate, drying adjunct and adjuncts. As spray drying temperature increased, bulk density, rehydration speed, moisture content and water activity were found slightly decreased, but flowability and particle diameter slightly increased. As the feeding speed increased, moisture content, water activity and particle diameter increased but no significant difference was found in other properties. As the amount of drying adjunct increased, bulk density, flowability, moisture content, water activity and particle diameter decreased, but viscosity increased. The benefit effect of color and flowability of papaya milk powder prepared with addition of sodium bisulfite and tricalcium phosphate. The bulk density, flowability and particle diameter of 20% papaya juice, 20% milk powder were decreased than 20% papaya juice, 10% milk powder, and 10% maltodextrin. The sensory evaluation showed that the combination of 20% papaya juice, 10% milk powder, and 10% maltodextrin was the best formula. The optimum conditions for the spray drying were as follows： the spray drying temperature of papaya milk was 100n4 ℃, feeding rate was 2.5 ml/min, and maltodextrin, sodium bisulfite and tricalcium phosphate additives were 10%, 0.05% and 0.2%, respectively. The combination of 20% papaya juice, 10% milk powder, and 10% maltodextrin was found, the best formula for properties and sensory evaluation of papaya milk powder.

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49

Chao, Yi-hung, and 趙羿竑. "Studies on the Component Analysis of Different Drying Methods in Salvia miltiorrhiza." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/bff34s.

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碩士
國立屏東科技大學
農園生產系所
105
Danshen (Salvia miltiorrhiza Bunge), whose roots were often used as medicine, belongs to the family Labiatae and Salvia genus. The main active components are two categories that the lipophilic diterpenoids and the hydrophilic phenolic acids. Post-harvest drying is the important procedure in order to preserve Chinese herbal medicine. But the active ingredients of danshen is unstable, susceptible to temperature and external environmental changes. So the experiment is discussing the differences by HPLC (High performance liquid chromatography) component analysis method to explore the idifferent drying methods such as freeze-drying, hot air drying, shade drying and sun drying for the roots of danshen in the active ingredients of the impact. The results show the highest content of phenolic acids is in freeze-drying that danshensu is 744.89±51.89 μg/g, salvianolic acid B is 13,534.37±417.42 μg/g and salvianolic acid A is 387.39 ± 16.95 μg/g, The highest content of tanshinone is in sunburn that dihydrotanshinone is 120.50±4.72 μg/g, cryptotanshinone is 657.86±34.77 μg/g, tanshinone I 240.24±22.04 μg/g and tanshinone IIA is 600.66±40.31 μg/g, second is by freeze-drying. The drying test was carried out at 40℃, 50℃, 60℃ and 70℃, respectively. The results showed that the highest content of phenolic acids is at 50℃ that danshensu is 503.70±25.41 μg/g, salvianolic acid B is 17,110.78±466.40 μg/g and salvianolic acid A is 166.58±11.00 μg/g, The tanshinones were best at 50℃, dihydrotanshinone is 97.08±2.72 μg/g and 70℃ dried cryptotanshinone is 461.65±27.73 μg/g, tanshinone I is 294.42±14.74 μg/g and tanshinone IIA 768.78±154.55 μg/g. 50℃ drying and 70℃ have the best contents. The results showed that the content of active ingredients in S. miltiorrhiza was higher by freeze drying, and 50℃ was the best when dried by hot air drying.

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50

Hong, Shih-Kai, and æ´ªæå±. "The Study of Different Drying Methods to PC Material in Printing Reproduction Quality." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/75527872174036599931.

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碩士
中國文化大學
資訊傳播研究所
92
Abstract This thesis is to see if different source of heat, setting of heat (including temperature, setting of heat) effects the dryness of ink on screen printing. In advance establishes a model of dryness and setting of heat on screen print. In order to establish the dryness of screen print on optical PC (Polycarbonate) material this research is tested under an ATM FB-500 flat single screen printer, and Champion’s traditional screen ink printed in K(Black), (Cyan), M(Magenta), Y(Yellow) order by changing source of heat and setting of heat(including temperature, setting of heat). Moreover, the source of heat includes Infrared Radiation, Hot Wind, and Mixed method(that is Infrared Radiation with Hot Wind). The temperature of heat includes 60℃,80℃and 100℃. The setting of heat is set up in K, C, M, and Y(is always 100℃). The conclusion, based on the results of experiments conducts in this research, is as following： This research shows it is significant contribution when changing the dryness of heat, temperature, and the setting of heat on quality of screen print according limited the quality effect on dot gain, printing contrast, trapping, and solid density. From dot gain point, the best result is mixed. And the second is hot wind, finally is infrared radiation. From print contrast point, the best result is infrared radiation. And the second is hot wind, and the third is mixed. From trapping point, the best result is mixed. And the second is hot wind, and the worst is infrared radiation. From solid density point, the best result is mixed. The second is infrared radiation, and the worst is hot wind. If we consider dot gain, trapping, and solid density as the first quality, the best result is mixed. By contrast, if we consider printing contrast as the first quality, the best result is infrared radiation. In the mixed, we use Simplex’s algorithm as the effect of quality as instance. The optical temperature of setting in each print unit: K unit is 60℃, C is 76.3℃,and M is 88.04℃. In the infrared radiation, we use Simplex’s algorithm as the effect of quality as instance. The optical temperature of setting in each print unit: K is 60℃, C is 74.06℃,is 60℃. In the hot wind, we use Simplex’s algorithm as the effect of quality as instance. The optical temperature of setting in each print unit: K is76.92℃, C is 60℃,M is 75.41℃. The research establishes a calculated model to find out the optical source of heat in different printing quality. User only needs to plug into the Z_DG, Z_PC, Z_TRAP, and Z_SID value, and then can get the hot source temperature of 4 printing units in Infrared Radiation, Hot Wind, and Mixed.

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Dissertations / Theses on the topic 'Drying methods'

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