294 research outputs found

    A numerical approach for modelling thin cracked plates with XFEM

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    The modelization of bending plates with through the thickness cracks is investigated. We consider the Kirchhoff-Love plate model which is valid for very thin plates. We apply the eXtended Finite Element Method (XFEM) strategy: enrichment of the finite element space with the asymptotic bending and with the discontinuity across the crack. We present two variants and their numerical validations and also a numerical computation of the stress intensity factors

    Analysis and Verification of Service Interaction Protocols - A Brief Survey

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    Modeling and analysis of interactions among services is a crucial issue in Service-Oriented Computing. Composing Web services is a complicated task which requires techniques and tools to verify that the new system will behave correctly. In this paper, we first overview some formal models proposed in the literature to describe services. Second, we give a brief survey of verification techniques that can be used to analyse services and their interaction. Last, we focus on the realizability and conformance of choreographies.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330

    Solubility of Chitin: Solvents, Solution Behaviors and Their Related Mechanisms

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    Chitin is a natural polysaccharides having a unique molecular arrangement of 2-(acetylamino)-2-deoxy-d-glucose, it possesses multifunctional properties and is suitable for various applications mainly in pharmaceutical, biomedical food, textiles and packaging fields. Therefore, being considered as a superior material for a sustainable future of industrial development, chitin perfectly meets up the demands with diversified functionalities in applications, excellent biocompatibility and biodegradability. Non-toxicity to human and environment (air, water and soil) is a great opportunity for this revolutionary, innovative and sustainable material. Moreover, antibacterial potency and low immunogenicity of chitin have broadened the aspects of research and development on structure-function relationship toward biological tissues and activities. Despite abundance, low cost and availability, many experimental data from potential studies, reproducibility problems of chitin solubility measurement still limit the development of products and access to the market in large volume. Batch-to-batch variability, non-precise characterization and randomly distributed acetyl groups of chitin structure eventually results in a bad reproducibility of chitin solubility. Therefore, the chapter aims to organize the information of chitin structure at molecular level and correlate solubility with chitin structure. Moreover, the dissolution mechanism and solution behaviors in different solvents will be discussed in this chapter

    Tau Be or not Tau Be? - A Perspective on Service Compatibility and Substitutability

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    One of the main open research issues in Service Oriented Computing is to propose automated techniques to analyse service interfaces. A first problem, called compatibility, aims at determining whether a set of services (two in this paper) can be composed together and interact with each other as expected. Another related problem is to check the substitutability of one service with another. These problems are especially difficult when behavioural descriptions (i.e., message calls and their ordering) are taken into account in service interfaces. Interfaces should capture as faithfully as possible the service behaviour to make their automated analysis possible while not exhibiting implementation details. In this position paper, we choose Labelled Transition Systems to specify the behavioural part of service interfaces. In particular, we show that internal behaviours (tau transitions) are necessary in these transition systems in order to detect subtle errors that may occur when composing a set of services together. We also show that tau transitions should be handled differently in the compatibility and substitutability problem: the former problem requires to check if the compatibility is preserved every time a tau transition is traversed in one interface, whereas the latter requires a precise analysis of tau branchings in order to make the substitution preserve the properties (e.g., a compatibility notion) which were ensured before replacement.Comment: In Proceedings WCSI 2010, arXiv:1010.233

    Toward a better understanding of tool wear effect through a comparison between experiments and SPH numerical modelling of machining hard materials

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    The aim of this study is to improve the general understanding of tungsten carbide (WC–Co) tool wear under dry machining of the hard-to-cut titanium alloy Ti6Al4V. The chosen approach includes experimental and numerical tests. The experimental part is designed to identify wear mechanisms using cutting force measurements, scanning electron microscope observations and optical profilometer analysis. Machining tests were conducted in the orthogonal cutting framework and showed a strong evolution of the cutting forces and the chip profiles with tool wear. Then, a numerical method has been used in order to model the machining process with both new and worn tools. The use of smoothed particle hydrodynamics model (SPH model) as a numerical tool for a better understanding of the chip formation with worn tools is a key aspect of this work. The redicted chip morphology and the cutting force evolution with respect to the tool wear are qualitatively compared with experimental trends. The chip formation mechanisms during dry cutting process are shown to be quite dependent from the worn tool geometry. These mechanisms explain the high variation of the experimental and numerical feed force between new and worn tools

    Plant extract enhances the viability of Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus acidophilus in probiotic nonfat yogurt

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    Citation: Michael, M., Phebus, R. K., & Schmidt, K. A. (2015). Plant extract enhances the viability of Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus acidophilus in probiotic nonfat yogurt. Food Science & Nutrition, 3(1), 48-55. doi:10.1002/fsn3.189A commercial plant extract (prepared from olive, garlic, onion and citrus extracts with sodium acetate (SA) as a carrier) was evaluated to extend the viability of yogurt starter and probiotic bacteria as a means to enhance the shelf life of live and active culture, probiotic nonfat yogurt. Yogurts prepared from three different formulas (0.5% plant extract, 0.25% SA, or no supplement) and cultures (yogurt starter plus Bifidobacterium animalis, Lactobacillus acidophilus, or both probiotics) were assessed weekly during 29 days of storage at 5 degrees C. Supplemented yogurt mixes had greater buffering capacities than non-supplemented yogurt mixes. At the end of storage, Lactobacillus bulgaricus and L. acidophilus counts in supplemented yogurts were greater compared with non-supplemented yogurts. Supplementation did not affect Streptococcus thermophilus and B. animalis counts. Hence the greater buffering capacity of yogurt containing plant extract could enhance the longevity of the probiotics, L. bulgaricus and L. acidophilus, during storage

    Multilevel Contracts for Trusted Components

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    This article contributes to the design and the verification of trusted components and services. The contracts are declined at several levels to cover then different facets, such as component consistency, compatibility or correctness. The article introduces multilevel contracts and a design+verification process for handling and analysing these contracts in component models. The approach is implemented with the COSTO platform that supports the Kmelia component model. A case study illustrates the overall approach.Comment: In Proceedings WCSI 2010, arXiv:1010.233

    Contract Aware Components, 10 years after

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    The notion of contract aware components has been published roughly ten years ago and is now becoming mainstream in several fields where the usage of software components is seen as critical. The goal of this paper is to survey domains such as Embedded Systems or Service Oriented Architecture where the notion of contract aware components has been influential. For each of these domains we briefly describe what has been done with this idea and we discuss the remaining challenges.Comment: In Proceedings WCSI 2010, arXiv:1010.233

    Effects of rearing system on performance, animal welfare and meat quality in two pig genotypes

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    Abstract The effects of an alternative rearing system (O) for growing-finishing pigs (sawdust-shave bedding with free outdoor access, 2.4 m²/pig) compared to a conventional (C) one (slatted floor, 0.65 m²/pig) were evaluated for performance, animal welfare and meat quality in two (Duroc or synthetic line crossbreds) genotypes. Trials were conducted in spring and winter, each involving one pen of 10 pigs / genotype / system (a total of 40 pigs / season). No significant interactions between rearing system and genotype were observed on any of the traits evaluated. On the whole, the O pigs spent 40% more time on exploratory activities, in particular towards the bedding, suggesting an improved animal welfare with the O system. Urine levels of cortisol and catecholamines in the O were similar with those in C pigs at 70kg. The O pigs exhibited a 6% increase in growth rate and were 5kg heavier at slaughter at the same age. Back fat depth and lean meat content, as well as plasma ACTH and cortisol, and urine cortisol and catecholamines levels at slaughter were not significantly affected by the rearing system. The O pigs exhibited similar pH 1 and pHu values, higher drip losses, but also higher intramuscular fat contents. The O system improved loin juiciness, but did not influence other eating quality traits

    Husbandry factors and health conditions influencing the productivity of French rabbit farms

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    [EN] In 2009 productivity data from 95 kindling to finishing rabbit farms in France were analysed to identify rearing factors and health conditions that influenced their productivity. Farm productivity, expressed on a yearly basis, was described with 4 productivity indices: doe fertility and prolificacy, viability of young rabbits in the nest and mortality during the fattening period. The productivity data were obtained with the technical support of the farm and expressed in a standardised way. The average numerical productivity observed in the sample of farms was 50.9 rabbits produced per doe and per year (CI95% [49.6-52.2]). The husbandry management and health conditions were described based on a questionnaire filled out during an interview with the farmer and a farm visit. Explanatory data were organised into meaningful blocks relative to biosecurity measures, del using a Partiamaternity management, the sanitary context and the farm structure. The relationship between the 4 thematic blocks and the productivity indices was studied in a single mol Least Squares (PLS) regression model. Fertility (81.0%, CI95% [80.0-82.0]) and viability of young at nest (85.1%, CI95% [85.0-85.3] and mortality rate during fattening: 7.2%, CI95% [6.4-7.9]) were significantly associated with common factors relative to maternity management and the health context whereas prolificacy (9.7 live kits per parturition, CI95% [9.5-9.9]) was mostly influenced by a specific set of variables pertaining to those 2 blocks. Farm structure and biosecurity measures had a limited impact on fertility and on kit viability before weaning. The health conditions of the doe herd and the fattening rabbits were found to be significantly associated with several productivity indexes, but their impacts on productivity were as high as the impact of the other blocks. Genetic strain of the females, doe replacement strategy and nursing and weaning practices appeared to significantly influence reproductive performance, viability of kits before weaning and mortality rate during the fattening period. Maternity management therefore seemed to be the key point in rabbit unit management that governed the numerical productivity of the farm.The authors wish to acknowledge the CLIPP-Lapin de France, the SNGTV (French Veterinary Society - rabbit branch) and the FFC (French Federation of Cuniculture) for their collaboration. We also wish to thank the farmers and the rabbit production organisations who participated in the study. The authors are grateful to Ms. Anaïs Croisier for her participation as an investigator and to Mr. Guillaume Coutelet from the French Institute for Avian Production for his technical expertise. Funding was provided by the French Agency for Veterinary Medicinal Products (ANSES-ANMV)Huneau-Salaün, A.; Bougeard, S.; Balaine, L.; Eono, F.; Le Bouquin, S.; Chauvin, C. (2015). Husbandry factors and health conditions influencing the productivity of French rabbit farms. World Rabbit Science. 23(1):27-37. https://doi.org/10.4995/wrs.2015.3076SWORD2737231Castellini, C., Dal Bosco, A., Arias-Álvarez, M., Lorenzo, P. L., Cardinali, R., & Rebollar, P. G. (2010). The main factors affecting the reproductive performance of rabbit does: A review. Animal Reproduction Science, 122(3-4), 174-182. doi:10.1016/j.anireprosci.2010.10.003Coutelet G. 2011. Performances moyennes des élevages cunicoles en France pour l'année 2010. Cuniculture Magazine, 38: 24-27.EFSA. 2005. Scientific Opinion of the Scientific Panel on Animal Health and Welfare on the impact of the current housing and husbandry systems on the health and welfare of farmed domestic rabbits. EFSA J., 2005: 1-31.Lebas F. 2010. Situation cunicole en France en 2009: performances moyennes des élevages selon les résultats du RENACEB pour l'année 2009, situation du marché cunicole français et premières évaluations pour l'année 2010. Cuniculture Magazine, 37: 74-82.Licois D., Coudert P., Marlier D. 2006. Epizootic rabbit enteropathy. In: L. Maertens, P. Coudert (ed). Recent advances in rabbit sciences. Institute for Agricultural and Fisheries Research, Melle, Belgium, 163-170.Marongiu M.L., Dimauro C., Floris B. 2007. A six-year investigation on reproductive performance of hybrid rabbits. 1. Pregnancy rate and numerical productivity at weaning as affected by season. Ital. J. Anim. Sci., 6: 770-772.Rommers J., Maertens L., Kemp B. 2006. New perspectives in rearing systems for rabbit does. In: L. Maertens, P. Coudert (ed). Recent advances in rabbit sciences. Institute for Agricultural and Fisheries Research, Melle, Belgium, 39-51.Serrano P., Pascual M., Gómez E.A. 2012. Analysis of management techniques on productivity indicators using the bdcuni Spanish database. In Proc.: 10th World Rabbit Congress, 3-6 September, 2012. Sharm El-Sheikh, Egypt. 1: 803-807
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