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A mathematical model of the behaviour of a fish solar dryer has been described. This model has allowed an optimization of the design of this dryer (solar-chimney area and height, insolator area, etc...). The natural convection had to pulse drying air inside apparatus, whose capacity should be 30 kg of fresh fish. Then the dryer has been built in National Fishing School of Anjouan (Comores Island). The first results mean a good fit between theoretical and experimental results. The air-insolator, used for air heating, is a porous type, made with blacked coco fibers, crossed by the drying air. This local material is confirmed as a good thermic interface. The most sensitive parameter, on the drying time, is the thickness of the fish slices. The choice of the fish quality is also very important: each different fish is characterized by one or several specific value of the water diffusivity constant, Dm. The model uses experimental values for the calculation. Then the Fick's diffusion equation may be solved by decomposition of the moisture content inside fish slice (Fourier analysis). Un modeéle matheématique du comportement d'un seéchoir solaire, destineé aà seécher du poisson, a eété eécrit. II a permis d'optimiser au mieux la geéomeétric de ce seéchoir qui a pu eêtre construit sur le site de I'eécole Nationale de peêche d'Anjouan aux Comores. II s'agit d'un seéchoir fonctionnant grace aà la convection naturelle, et dont la capacite est d'environ 30 kg. L'air de seéchage est chauffeé par un capteur solaire de type absorbeur poreux, reéaliseé en bourre de noix de coco noircie. Le choix de ce mateériau local est bien suÛr volontaire; il s'est par ailleurs aveéreé comme un excellent milieu d'eéchange thermique. Le parameètre le plus sensible sur la dureée de sechage est l'eépaisseur des filets de poisson. La qualiteé du poisson est aussi un choix important, chacun posseédant une constante de diffusiviteé de l'eau, Dm, bien speécifique. Le modeèle utilise les valeurs expeérimentales de cette constante. L'eéquation de Fick, qui reégit la migration de l'eau dans un mateériau poreux, peut alors eâtre reésolue en utiiisant une deécomposition en seérie de Fourier, de la reépartition de l'eau dans les tranches de poisson. 相似文献
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Numerical simulation of complex flows of viscoelastic fluids requires the use of efficient algorithms for solving the non-linear governing equations. In this paper, optimization algorithms, associated to a non-linear least squares methods are considered. The governing equations are written in the context of stream-tube analysis. This method is particularly adapted to handle memory-integral constitutive equations and permits calculation of flows by considering elementary sub-domains in a mapped computational domain where the transformed streamlines are parallel and straight. The procedure used to solve the equations is the Trust Region optimization algorithm, which satisfies a global convergence property. Using an integral codeformational equation, various tests involving the influence of parameters of the algorithms are applied to different flow geometries and underline the robustness and efficiency of the Trust Region algorithm. 相似文献
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Gas exchange in modified atmosphere packaging. 2: Experimental results with strawberries 总被引:3,自引:0,他引:3
PIERRE RENAULT LYDIE HOUAL GUY JACQUEMIN YVES CHAMBROY 《International Journal of Food Science & Technology》1994,29(4):379-394
Strawberries were used to test a new model describing gas transport through micro-perforated polypropylene films and fruit respiration involved in modified atmosphere packaging. Some experiments were conducted with empty packs initially filled with either 100% N2 or 100% O2 . Simulations agreed very well with experiments only if we replaced the cross-sectional area of the micro-perforations by areas of approximately half the actual areas in order to account for the resistance of air around the perforations. It is also possible to fit the model to gas concentration changes in packs filled with strawberries, although deviations have been due to the contamination of strawberries by fungi. the model was used to quantify the consequences of the variability of pack properties (number of micro-perforations per pack and cross-sectional area of these perforations) on equilibrium gas concentrations and to define minimum homogeneity requirements for modified atmosphere packaging. 相似文献
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Gas exchange in modified atmosphere packaging. 1: A new theoretical approach for micro-perforated packs 总被引:2,自引:0,他引:2
PIERRE RENAULT MICHEL SOUTY YVES CHAMBROY 《International Journal of Food Science & Technology》1994,29(4):365-378
Gas transport and exchange through the perforations in micro-perforated packs used in modified atmosphere packaging were numerically modelled by using Stephan-Maxwell laws, and, outside these perforations, by Fick's law. the model accounts simultaneously for oxygen, carbon dioxide, nitrogen, argon and water vapour. Fruit and vegetable respiration was approximated by Michaelis-Menten kinetics depending on oxygen concentration with an uncompetitive inhibition due to carbon dioxide. Concentration equilibrium was reached after 2 to 3 days, depending on the void volume and on the diffusion properties of the packs. the equilibrium concentrations were dependent on the number of perforations, their diameter, the thickness of the film and the temperature. However, a pack which makes 10% oxygen possible within the pack at 10°C might induce anaerobiosis at 20°C. 相似文献
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MICHEL POULIOT PAUL PAQUIN RICHARD MARTEL SYLVIE F. GAUTHIER YVES POULIOT 《Journal of food science》1997,62(3):475-479
We assessed the potential application of near infrared (NIR) spectrophotometry using a remote optic fiber probe for the development of calibrations. We evaluated the heat denaturation of whey proteins, the chemical composition of a whey protein concentrate (WPC) during production, and the degree of hydrolysis (DH) of whey proteins during trypsin hydrolysis. Partial least square (PLS) calibrations were developed for these applications and were related to a variety of products and processing conditions, so as to increase their reliability. NIR has potential applications in real time analysis for whey processing lines. 相似文献
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ARNOLD FERTIN LAURE LAFORGUE ALAIN DUPERRAY VALÉRIE M. LAURENT YVES USSON CLAUDE VERDIER 《Journal of microscopy》2019,275(3):172-182
Living cells embedded in a complex extra-cellular matrix migrate in a sophisticated way thanks to adhesions to matrix fibres and contractility. It is important to know what kind of forces are exerted by the cells. Here, we use reflectance confocal microscopy to locate fibres accurately and determine displacement fields. Correlation techniques are used to this aim, coupled with proper digital image processing. Benchmark tests validate the method in the case of shear and stretching motions. Finally, the method is tested successfully for studying cancer cells migrating in collagen gels of different concentration. 相似文献
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MICHEL BARé DOLORES CAN¯ AMERO JEAN-FRANCOIS DELANNOY YVES KODRATOFF CNRS-LRI 《Applied Artificial Intelligence》2013,27(4):617-643
In the context of a command, control, communication, and intelligence (Cff) system, we have built a case-based reasoning module for plan recognition. It is based on knowledge representation structures called XPlans, inspired in part by Schank's Explanation Patterns. The uncertainty inherent to an uncontrolled flow of input and the presence of lacunar data make the retrieval of cases difficult. This led us to develop an algorithm for partial and progressive matching of the target case onto some of the source cases. This matching amounts in practice to a credit assignment mechanism, included in the algorithm associated with each XPlan. This method has been designed to meet the requirements of a DRET project to build a decision support module for a C3I system— the MATIS project. Its task is to interpret and complete the results of an intelligent “ pattern-recognition-and-data-fusion” module in order to make the intentions underlying the recognized situation explicit to the decision maker. This advice is given as a causal explanation of an agent's behavior from low-level information. 相似文献
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SERGE BÉROT SYLVIE GAUTIER MICHEL NICOLAS BERNARD GODON YVES POPINEAU 《International Journal of Food Science & Technology》1994,29(5):489-502
Commercial wheat gluten was fractionated on a pilot plant scale to produce gliadin-and glutenin-rich fractions. Acetic acid solutions (0.01–0.05 M) were blended with dry gluten (16, 10 or 7 volumes unit-1 of dry gluten ratio) and the slurry was separated by continuous centrifugation to yield a gliadin-rich supernatant, which was then concentrated by ultrafiltration and spray-dried. the pellet obtained was optionally rinsed by water or acetic acid and separated in a second stage. the second supernatant was treated as the first one, and the final residue, insoluble and glutenin-rich, was then dispersed in ammonia and spray-dried. the protein distributions in supernatants and residues depended on pH and ranged from 20/80 to 40/60 for the first stage, and from 40/60 to 80/20 for the sum of the two stages. the compositions of the fractions were measured by solubility tests and size exclusion high performance liquid chromatography (SE-HPLC) profiles. A [-1, +1] selectivity scale was created: each fraction was compared to pure gliadins (-1), gluten (0) and pure glutenins (+1). the best combination between yields of soluble and insoluble fractions (40/60 distribution) and selectivities for gliadins and glutenins (-0.32 and +0.26 respectively) was obtained at ratio 16 and a 0.01 M molarity. Though the selectivities were limited because gliadins and medium-size glutenin polymers have similar solubilities in acid solutions, this process permits preparation of fractions which differ widely from gluten in contents of high molecular weight glutenin polymers. 相似文献