395 research outputs found

    Prédiction de la profondeur de sol humidifié sous goutteur

    Get PDF
    A partir de résultats expérimentaux, des équations d'infiltration et de continuité, nous avons établi une équation permettant de prédire la profondeur maximale humidifiée par un goutteur à la surface du sol. Connaissant l'humidité initiale du sol Øi, la conductivité hydraulique Kf et la teneur en eau au niveau du front Øi ; l'équation établie permet de calculer la profondeur du front d'humectation Zf(t) à partir du suivi du rayon du front d'humectation Rf(t) à la surface du sol. Pour tester la validité de cette nouvelle approche, des essais ont été menés sur deux types de sol (sableux et limono-argileux) et avec trois débits différents. Les valeurs de Zf(t) mesurées (par deux techniques différentes) ont été comparées à celles calculées par cette équation, les résultats étaient, dans tous les cas, quasi-identiques (coefficient de corrélation R2, dans tous les cas, supérieur ou égal à 0.94).In trickle irrigation, the wetted soil volume fraction (P) is a fundamental parameter for both network design and irrigation scheduling. However, methods used to determine such parameter (P) are still limited and unaccurate. Further, numerical models established for predicting wetted soil volume (or bulb) dimensions remain onerous, complex, expensive, and therefore hardly used. Experimental and numerical results performed on water infiltration from point source on the soil surface show a close relationship between the horizontal and vertical bulb dimensions. This study which was based on continuity and cumulative infiltration equations allowed to establish a new and simple equation for predicting wetted soil depth. This equation enables, knowing initial and wetting front water content and K(hf) (soil hydraulic conductivity on the wetting front), to calculate the front depth Zf(t) beneath a point source with only measuring the front radius Rf(t) on the soil surface. The established equation verifies physical conditions of axisymmetric water infiltration into the soil. The established equation was tested by performing trials on two different soil types and three discharge rates. Two different procedures were simultaneously used for determining Rf(t) and Zf(t). i) observing bulb dimensions evolution on the soil surface and along the symmetry axis. ii) Rf(t) and Zf(t) values were inferred from the horizontal and vertical suction profiles respectively. The Zf(t) values calculated, using such equation, are compared with those measured. The results obtained showed good agreement between calculated and measured data (R2 >=0.94). This study was performed during an axisymmetric water infiltration into bare, homogeneous, and isotropic soil. It needs to be extended to heteregeneous, anisotropic and cultivated soils

    Corrosion Durability and Structural Response of Functionally-Graded Concrete Beams

    Get PDF
    This paper reports the results of an experimental program on the effectiveness of a Ductile Fiber Reinforced Cementitious Composite (DFRCC) material, which exhibit strain-hardening and multiple-cracking bahavior under flexural loadings, in retarding the corrosion of steel in Reinforced Concrete (RC) beams. Based on the collective findings from theoretically-estimated steel losses, rapid chloride permeability tests, pH value tests, as well as structural tests, it was concluded that Functionally-Graded Concrete (FGC) beams, where a layer of DFRCC material was used around the main longitudinal reinforcement, had a noticeably higher resistance against reinforcement corrosion compared to a conventional RC beam. The better performance of the FGC beams was also evident from the absence of any corrosion-induced cracking and the very low tendency of the concrete cover to delaminate as measured by a concrete-embeddable fiber optic sensor

    Development of ductile fibre reinforced geopolymer composites

    Get PDF

    In vitro vegetative growth and flowering of olive tree in response to GA3 treatment

    Get PDF
    The phytohormone gibberellin is involved in the regulation of many physiological process including flower induction and shoot growth. In this study, gibberellic acid (GA3) was used in order to induce thereversion of olive tree vegetative buds towards a floral ones in vitro. For this, six varieties (Marsaline, Chemchali, Picholine, Chemlali, Zalmati and Oueslati ) was tested and explants, consisting of a singlenode segments, were grown in media containing three concentrations of GA3 (1, 2 and 10 mg/l). Results show that Marsaline seems to be the most able variety in regenerating floral structures. For this variety,5 cases of reversion were observed mainly on the medium containing 10 mg/l GA3. This same medium was also favorable for this transformation for the other varieties (3 cases on Picholine, one each on Chemchali , Zalmati and Oueslati). The examination of the histological sections confirmed this transformation. In addition, this experiment showed that GA3 can be at the origin of an interestinggrowth rate of vegetative buds, which elongation depend on variety as well as GA3 concentration

    Fibrosarcome du larynx - A propos d'un cas

    Get PDF
    Le fibrosarcome du larynx est une entitĂ© histologique rare, qui reprĂ©sente moins de 10% de tous les sarcomes des tissus mous, moins de 2 % des cancers laryngĂ©s. Cette localisation pose des problĂšmes diagnostique, thĂ©rapeutique et pronostique. Nous prĂ©sentons un cas de fibrosarcome laryngĂ© chez un patient de 54 ans. La confirmation histologique etimmunohistologique a Ă©tĂ© faite sur la piĂšce d’exĂ©rĂšse chirurgicale et surtout sur une confrontation anatomoclinique. La prise en charge thĂ©rapeutique est multidisciplinaire, associant la chirurgie qui doit ĂȘtre la plus complĂšte sans curage ganglionnaire et la radiothĂ©rapie. Le pronostic est gĂ©nĂ©ralement sĂ©vĂšre, dĂ©pend essentiellement de degrĂ© de diffĂ©renciation histologique.Mots clĂ©s : fibrosarcome ; larynx ; chirurgie ; radiothĂ©rapie

    Correlation anatomo-scannographique dans le cancer du larynx

    Get PDF
    Introduction : Le but de la chirurgie du larynx est de conserver dans la mesure du possible un larynx fonctionnel tout en rĂ©pondant aux impĂ©ratifs carcinologiques. Les limites d'extension tumorale doivent ĂȘtre finement analysĂ©es en prĂ©-opĂ©ratoire pour adopter la technique opĂ©ratoire appropriĂ©e. dans ce domaine, l'apport de la TdM est incontestable pour l'Ă©tude de cette extension en profondeur.Patients et mĂ©thodes : il s'agit d'une Ă©tude rĂ©trospective des dossiers de 43 patients explorĂ©s et traitĂ©s respectivement aux services d'imagerie mĂ©dicale et d'ORL de l'hĂŽpital Tahar Sfar de Mahdia sur une pĂ©riode de 14 ans entre Janvier 1995 et dĂ©cembre 2008.RĂ©sultats : La classification prĂ©-opĂ©ratoire des tumeurs pharyngo-laryngĂ©es est plus fiable en se basant Ă  la fois sur l’endoscopie et la TdM que sur l’endoscopie seule. La fiabilitĂ© de cette association Ă©tait de 76%. L'Ă©tude de certaines zones dites d'intĂ©rĂȘt a montrĂ© une efficacitĂ© de 72% pour l'atteinte de la commissure antĂ©rieure, de 79% pour les bandes ventriculaires, de 81% pour la sous glotte, de 88% pour la loge HTE, de 83% pour les espaces para-glottiques et de 79% pour les cartilages. Nos rĂ©sultats Ă©taient concordants Ă  ceux de la littĂ©rature.Discussion et conclusion : la TdM constitue une partie intĂ©grante du bilan prĂ©opĂ©ratoire des cancers du pharyngolarynx. Elle prĂ©cise l'extension tumorale en profondeur aux espaces graisseux, aux cartilages et aux tissus extralaryngĂ©s. L’analyse fine des images tomodensitomĂ©triques permet donc d’orienter la dĂ©cision thĂ©rapeutique.Mots clĂ©s : cancer, larynx, anatomopathologie, chirurgie

    The Unfulfilled Potential of Data-Driven Decision Making in Agile Software Development

    Get PDF
    With the general trend towards data-driven decision making (DDDM), organizations are looking for ways to use DDDM to improve their decisions. However, few studies have looked into the practitioners view of DDDM, in particular for agile organizations. In this paper we investigated the experiences of using DDDM, and how data can improve decision making. An emailed questionnaire was sent out to 124 industry practitioners in agile software developing companies, of which 84 answered. The results show that few practitioners indicated a widespread use of DDDM in their current decision making practices. The practitioners were more positive to its future use for higher-level and more general decision making, fairly positive to its use for requirements elicitation and prioritization decisions, while being less positive to its future use at the team level. The practitioners do see a lot of potential for DDDM in an agile context; however, currently unfulfilled

    Prise en charge de l’atresie choanale

    Get PDF
    Introduction: L’atrĂ©sie choanale est une malformation congĂ©nitale rare mais non exceptionnelle. Le but de notre travail est d’étudier les caractĂ©ristiques Ă©pidĂ©miologiques, cliniques et radiologiques de cette pathologie, et de discuter les diffĂ©rentes modalitĂ©s thĂ©rapeutiques et leurs rĂ©sultats respectifs.MatĂ©riel et mĂ©thodes: Notre Ă©tude rĂ©trospective porte sur une sĂ©rie de 12 cas d’atrĂ©sie choanale opĂ©rĂ©s dans notre service entre 2002 et 2010. Tous les patients ont bĂ©nĂ©ficiĂ© d’un examen ORL et d’une tomodensitomĂ©trie du massif facial. Tous les patients ont Ă©tĂ© opĂ©rĂ©s sous anesthĂ©sie gĂ©nĂ©rale.RĂ©sultats: L’ñge moyen Ă©tait de 10,7 ans (3 jours - 31 ans) et le sex-ratio Ă©tait de 2. L’atteinte Ă©tait unilatĂ©rale dans 66,6% et bilatĂ©rale dans 33,3% des cas. Dans 16% des cas, l’atrĂ©sie rentrait dans le cadre d’un syndrome polymalformatif. La technique opĂ©ratoire utilisĂ©e Ă©tait la voie  endoscopique dans 10 cas et la voie transpalatine dans 2 cas. Le taux de succĂšs global Ă©tait de 75%. Trois cas de rĂ©cidive ont Ă©tĂ© notĂ©s. Ils ont Ă©tĂ© rĂ©opĂ©rĂ©s par voie endonasale.Conclusion: L’endoscopie nasale et la TDM permettent le diagnostic positif de l’atrĂ©sie choanale. Le traitement de rĂ©fĂ©rence actuellement est la chirurgie par voie endonasale.Mots-clĂ©s: atrĂ©sie choanale, malformation, obstruction nasale, endoscopie, tomodensitomĂ©trie, chirurgie endonasal
    • 

    corecore