294 research outputs found

    An improved result for the full justification of asymptotic models for the propagation of internal waves

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    We consider here asymptotic models that describe the propagation of one-dimensional internal waves at the interface between two layers of immiscible fluids of different densities, under the rigid lid assumption and with uneven bottoms. The aim of this paper is to show that the full justification result of the model obtained by Duch\^ene, Israwi and Talhouk [{\em SIAM J. Math. Anal.}, 47(1), 240--290], in the sense that it is consistent, well-posed, and that its solutions remain close to exact solutions of the full Euler system with corresponding initial data, can be improved in two directions. The first direction is taking into account medium amplitude topography variations and the second direction is allowing strong nonlinearity using a new pseudo-symmetrizer, thus canceling out the smallness assumptions of the Camassa-Holm regime for the well-posedness and stability results.Comment: arXiv admin note: substantial text overlap with arXiv:1304.4554; text overlap with arXiv:1208.6394 by other author

    Full justification of a new Green-Naghdi system for internal waves propagation over large topography variation

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    We consider here asymptotic models describing the evolution of internal waves propagating between a flat rigid-lid and a variable topography. In this paper, we derive and fully justify (in the sense of consistency, well-posedness and convergence) a new Green-Naghdi model in the Camassa-Holm regime taking into account large amplitude topography variations, thus relaxing the smallness assumption on the topographic variation parameter used in [Communications on Pure & Applied Analysis, 2015, 14 (6): 2203-2230] and hence improving the result of the aforementioned paper.Comment: arXiv admin note: text overlap with arXiv:1412.398

    Highlight on the problems generated by p-coumaric acid analysis in fermentations

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    p-Coumaric acid is a natural hydroxycinnamic acid existing in grapes and wine. It is the precursor of the 4-ethylphenol molecule through the bioconversion reaction by Brettanomyces yeast. Chromatographic methods are the most common techniques to detect p-coumaric acid. It is known that this acid is highly unstable in analysis and fermentation experiments. This paper highlights the problems occurring in p-coumaric acid analysis in wine fermentation conditions when studying its bioconversion. First, it was shown that p-coumaric acid was unstable at elevated temperature. On the other hand, it was found that in our experimental conditions p-coumaric acid reacted with ethanol. This work revealed also that the p-coumaric acid is partially adsorbed on Brettanomyces yeast, certainly on cell walls. Because of these phenomena the quantity of p-coumaric acid which can participate to the bioconversion into ethylphenol decreases

    Differentiation between Aspergillus flavus and Aspergillus parasiticus from Pure Culture and Aflatoxin-Contaminated Grapes Using PCR-RFLP Analysis of aflR-aflJ Intergenic Spacer

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    Aflatoxins (AFs) represent the most important single mycotoxin-related food safety problem in developed and developing countries as they have adverse effects on human and animal health. They are produced mainly by Aspergillus flavus and A. parasiticus. Both species have different aflatoxinogenic profile. In order to distinguish between A. flavus and A. parasiticus, gene-specific primers were designed to target the intergenic spacer (IGS) for the AF biosynthesis genes, aflJ and aflR. Polymerase chain reaction (PCR) products were subjected to restriction endonuclease analysis using BglII to look for restriction fragment length polymorphisms (RFLPs). Our result showed that both species displayed different PCR-based RFLP (PCR-RFLP) profile. PCR products from A. flavus cleaved into 3 fragments of 362, 210, and 102 bp. However, there is only one restriction site for this enzyme in the sequence of A. parasiticus that produced only 2 fragments of 363 and 311 bp. The method was successfully applied to contaminated grapes samples. This approach of differentiating these 2 species would be simpler, less costly, and quicker than conventional sequencing of PCR products and/or morphological identification

    Calculation of the C3A Percentage in High Sulfur Clinker

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    The aim of this paper is to clarify the influence of the clinker SO3 on the amount of C3A. The calculation of the cement phases percentages is based on the research work, Calculation of the Compounds in Portland Cement, published by Bogue in 1929 .The usage of high sulphur fuels, industrial wastes, and tires changes completely the working condition of Bogue because the assumed phase compositions may change. The results prove that increasing the amount of SO3 in the low alkali clinker decreases the percentages of C3A due to the high incorporation of alumina in the clinker phases mainly C2S and C3S. The correlation is linear till the clinker SO3 reaches the 2%. Over that the influence of the clinker SO3 became undetectable. A new calculation method for the determination of the C3A in the high sulphur and low alkali clinker was proposed

    Health Care Waste generation rates and patterns: The case of Lebanon

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    The objective of this study is to analyze Infectious Health Care Waste generation rates and patterns in Lebanon. Therefore, the quantities generated during five years by 57 hospitals from a total of 163 in the country have been analyzed. The seasonal evolution of Infectious Health Care Waste production and the evolution of the evaluation of the trends over years have been studied. Besides, the generation per capita have been estimated and compared to other countries. The variance between categories and the correlation between number of beds and Infectious Health Care Waste generation have been analyzed. The obtained results showed that the large private hospitals (over 200 beds) are characterized by their high generation rate: an average of 2.45 kg per occupied bed^-1 day^-1, whereas the average generation rate for other categories is 0.94 kg per occupied bed^-1 day^-1. The weighted mean is 1.14 per occupied kg bed^-1 day^-1. Small public hospitals (i.e. less than 100 beds) have the smallest standard deviation: 0.13, whereas large private hospitals (i.e. over than 200 beds) have the highest standard deviation: 0.40. Infectious Health Care Waste generation has been estimated to 1.42 kg/capita/year. The correlation between the numbers of hospitals beds in hospitals and the generation rate per bed is weak. The correlation between Infectious Health Care Waste generation per day and beds number is stronger. The total quantity produced by hospitals has increased over the five past years. These results suggest that the quantities of medical waste are not well controlled, and that hospitals have a defective monitoring management system of their waste. Annual peaks are observed in June, July, and December. Thus, this study, for the first time in Lebanon, has provided information on the infectious waste generation, allowing benchmarking between hospitals and between countrie

    Analysis of the effectiveness of a cereal milling by product monocomponent medium for the low cost production of Bacillus thuringiensis

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    Bacillus thuringiensis is a facultative anaerobe, gram positive, spore forming bacterium. The biotechnological importance of this bacterium resides in its ability to produce, during sporulation, crystal proteins known as delta-endotoxins which express specific insecticidal activity. At industrial scale, the culture media represents an important part of B. thuringiensis based biopesticides production cost. According to the literature, different agro-industrial residues and byproducts were used as sources of proteins in order to reduce the cost of B. thuringiensis culture medium, but carbohydrates (glucose, starch or molasses) and/or mineral sources were added. In this work, a cereal milling by-product (CMB) as a monocomponent medium was investigated and compared to synthetic mediums in terms of delta-endotoxin yield and productivity in submerged fermentation of different strains of B. thuringiensis. The CMB was shown efficient to be used as a complete substrate (source of proteins, carbohydrates and minerals) for B. thuringiensis production. The optimal CMB ratio in the culture medium was found to be 6% in shake flasks experiments. The consumption of the CMB sugars by the bacteria was analyzed. Production of the bio-insecticide in lab-bioreactor in controlled conditions was equally performed to give basic elements for extrapolation in industrial conditions

    Influence de l'étape de croissance et de la quantité de brettanomyces bruxellensis sur la production d'éthyl-phenols

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    Influence de l'étape de croissance et de la quantité de brettanomyces bruxellensis sur la production d'éthyl-phenol

    Indicators of Sustainable Development for Health Care Waste Treatment Industry

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    Sustainable development is more and more considered as a key parameter and a driving strategy for sustainable performance. Today, numerous organizations develop their own performance indicators as no standard set of performance indicators could be generalized as meaningful in terms of sustainability performance. Particularly, the context of developing countries, where the concept of sustainability is not well diffused yet and where economic difficulties and constraints result most of the times in underestimation of environmental and social considerations, requires specifically adapted indicators. Specially, the sector of health care waste management lacks of sustainability indicators. This sector ensures the treatment, before disposal, of hazardous health care waste generated by health care centers (hospitals, clinics, and others). The evaluation system is designed for monitoring the pace of gaining sustainability within this sector. The objective of this article is to propose a sustainability evaluation system adapted to the needs and situation of developing countries, based on meaningful, practical, easily measurable and applicable indicators for the Infectious Health Care Waste (IHCW) Treatment sector
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