Comportement au poinconnement de jonctions dalle-poteau de rive en beton armé de PRFV avec ou aans étriers armatures de cisaillement

Flat plates are commonly used in parking garages due to their functional and economic advantages. Slabs in parking garages are susceptible to accelerated deterioration due to harsh environment exposure as diffusion of de-icing salts, which, in turn, causing steel-corrosion problems. The use of Glass Fiber Reinforced Polymers (GFRP) bars has yielded a great interest as an innovative solution to overcome such problems. However, flat plate structural system is vulnerable to a type of brittle failure known as a punching-shear failure. This failure exaggerated more in the case of edge slab connections due to the lack of symmetry of the portion of the slab resisting the punching action and relatively large unbalanced moments to be transferred between the slab and column may produce significant shear stresses that increase the likelihood of brittle failure. Experimental and analytical investigations are carried out to examine the punching-shear strength and behavior of reinforced concrete (RC) edge slab-column connections totally reinforced in flexure with GFRP bars. The experimental work included edge slab-column connections without and with GFRP stirrups as shear reinforcement. Nine full-scale connections—one reinforced with steel bars for comparison, five reinforced solely with GFRP bars in flexural, and three reinforced with GFRP bars and stirrups—were constructed and tested to failure under combined vertical shear force and unbalanced moment. All slabs had identical geometries of 2500×1350×200 mm with a 300-mm square column stub protruding 700 mm above and below the slab surfaces. The investigated parameters are: (1) GFRP stirrups type (closed and spiral); (2) stirrups extension (1.75d and 4.25d); (3) flexural reinforcement ratio (1.04% and 1.55%) and type (steel and GFRP); (4) concrete strength (normal and high-strength concretes); and (5) moment-to-shear (M/V) ratios (0.3 m and 0.6 m). The analytical investigation is conducted through two phases. Phase I, focused on design codes assessment and proposing simplified design approaches for connections without and with shear reinforcement, respectively. Assessment of the available punching-shear equations provided by FRP design provisions , ACI 440.1R-15; CSA S806-12; and JSCE-97, is conducted by comparing their predictions against the experimental results for the tested connections and other specimens in the literature. Phase II focused on a 3D non-linear finite element analysis (FEA) using ANSYS software to simulate the behavior of the tested connections with shear reinforcement. Then, a comprehensive parametric study was performed to investigate the key parameters influencing the shear capacity of such connections. The test results revealed that the final mode of connections without shear reinforcement was punching shear failure with no signs of concrete crushing. However, existence of GFRP stirrups shear reinforcement was shown to be essential for significant warning before failure. GFRP stirrups shear reinforcement extended to 4.25d yielded a significant effect in enhancing the shear strength, deformation capacity and leading to mixed flexure/punching shear failure with considerable deformability. High-strength concrete directly enhanced punching-shear capacity, load-deflection response, initial stiffness as well as evidenced fewer and narrower cracks compared to their counterparts constructed with normal-strength concrete. Meanwhile, increasing the M/V ratio for normal and high strength concrete connections evidenced significant punching shear stresses causing reduction in the strength and limits the deformation capacity with subsequent brittle punching shear failure. On the other hand, the numerical results from the FEAs simulation adequately predicted the experimental responses for the tested GFRP edge connections with and without shear reinforcement and confirm the accuracy of the finite element model. Based on the results, a simplified design approach is proposed to estimate the punching capacity for GFRP-reinforced edge connections with shear stirrups. The model yielded good yet conservative predictions with respect to the experimental results as well as the available results in the literature. The recommendations presented herein may support the work of the North American technical committees engaged in the development of standards and design provisions for GFRP-RC slab-column connections columns subjected to combined vertical load and unbalanced moment.Les planchers-dalles ou dalles pleines sur poteaux sont couramment utilisés dans les stationnements en raison de leurs avantages fonctionnels et économiques. Les dalles de stationnements sont exposées à la dégradation accélérée due à l'exposition aux environnements rigoureux, comme la diffusion de sels de déverglaçage qui provoque des problèmes de corrosion de l'acier. L'utilisation de barres en polymère renforcé de fibres de verre (PRFV) a suscité un grand intérêt en tant que solution innovante pour résoudre de tels problèmes. Cependant, le système planchers-dalles est vulnérable à un type de rupture fragile appelée rupture par poinçonnement. Cette défaillance est encore plus amplifiée dans le cas des jonctions dalle-poteau de rive en raison de l’absence de symétrie de la partie de la dalle résistant au poinçonnement et des moments de transfert ou moments non équilibrés relativement importants à transférer entre la dalle et le poteau, pouvant produire des contraintes de cisaillement importantes, augmentant ainsi la probabilité de rupture fragile. Des études expérimentales et analytiques sont effectuées pour examiner la résistance au poinçonnement et le comportement des jonctions dalle-poteau de rive en béton armé, totalement renforcés en flexion avec des barres d’armature en PRFV. Le travail expérimental comprend des jonctions dalle-poteau de rive sans et avec des étriers en PRFV comme armature de cisaillement. Neuf (9) jonctions pleine grandeur (une jonction avec des barres d’armature en acier à des fins de comparaison, cinq jonctions avec uniquement des barres d’armature en flexion en PRFV et trois jonctions avec des barres et des étriers en PRFV) ont été fabriquées et testées jusqu'à la rupture sous une combinaison d’effort de cisaillement vertical et d’un moment non équilibré. Toutes les dalles avaient une géométrie identique de 2500 × 1350 × 200 mm avec un poteau de section carré de 300 mm de côté et ayant une saillie de 700 mm au-dessus et au-dessous des surfaces de la dalle. Les paramètres étudiés sont les suivants : (1) le type d'étrier en PRFV (fermé et en spirale) (2) – la longueur de prolongement des étriers (1,75d et 4,25d) (3) le taux d’armature en flexion (1,04 % et 1,55 %) et leur type (acier et PRFV) (4) la résistance en compression du béton (béton de résistance normale et béton à haute résistance) ; et (5) les rapports moment/cisaillement (M/V) (0,3 m et 0,6 m). L'étude analytique a été réalisée en deux phases. La phase I comportait l’évaluation des codes de conception et la proposition de méthodes de calcul simplifiées pour les jonctions sans et avec armatures de cisaillement. L'évaluation des équations de poinçonnement disponibles dans les dispositions de conception à l’aide des PRF, ACI 440.1R-15; CSA S806-12; and JSCE-97, est effectuée en comparant leurs prévisions aux résultats expérimentaux des jonctions testées et d’autres spécimens dans la littérature. La phase II s'est concentrée sur une analyse 3D non linéaire par éléments finis (FEA) à l’aide du logiciel ANSYS pour simuler le comportement des jonctions testées. Ensuite, une étude paramétrique complète a été réalisée pour étudier les paramètres clés influençant la résistance au cisaillement de telles jonctions. Les résultats des essais ont montré que le dernier mode de jonction avec et sans armatures de cisaillement était la rupture par poinçonnement sans aucun signe d’écrasement du béton ou de rupture par glissement des barres d’armature. Cependant, la présence d’armatures de cisaillement constituées d’étriers en PRFV s'est avérée être un signe avant-coureur d’une rupture. Les armatures de cisaillement constituées d’étriers en PRFV prolongés de 4,25d ont eu un effet significatif sur l'amélioration de la résistance au cisaillement, sur la capacité de déformation et ont conduit à un mode de rupture par poinçonnement adouci, avec une déformabilité considérable. Le béton à haute résistance a directement contribué à améliorer la résistance au poinçonnement, la réponse charge-flèche, la rigidité initiale avec des fissures moins nombreuses et plus étroites par rapport aux spécimens construits avec du béton de résistance normale. Entre-temps, l’augmentation du rapport M/V pour les jonctions en béton normal et en béton à haute résistance s’est traduite par des contraintes de poinçonnement importantes, entraînant une réduction de la résistance et une limitation de la capacité de déformation, avec une rupture par poinçonnement fragile. D'autre part, les résultats numériques de la simulation par éléments finis ont permis de prédire de manière adéquate les réponses expérimentales pour les jonctions de rive en PRFV testées avec et sans armatures de cisaillement et de confirmer la précision du modèle par éléments finis. Sur la base des résultats, deux méthodes simplifiées de calcul sont proposées pour estimer la résistance au poinçonnement des jonctions de rive avec et sans étriers de cisaillement en PRFV. Les modèles ont montré de bonnes prédictions, mais prudentes par rapport aux résultats expérimentaux et aux résultats disponibles dans la littérature. Les recommandations présentées dans le présent document peuvent soutenir les travaux des comités techniques nord-américains chargés de l’élaboration des normes et des dispositions de conception des jonctions dalle-poteau en béton armé de PRFV soumises à une charge verticale et à un moment non équilibré

Llet de cabra verge

Fa anys que l'enginyeria ramadera indueix la lactació mitjançant injecció directa d'estrogen i progesterona. Un nou avanç podria millorar, en un futur, l'efectivitat d'aquest tractament en cabres lleteres gràcies a la reserpina, un agent inductor de la prolactina.Hace años que la ingeniería ganadera induce la lactación mediante inyección directa de estrógeno y progesterona. Un nuevo avance podría mejorar en un futuro la efectividad de este tratamiento en cabras lecheras gracias a la reserpina, un agente inductor de la prolactina.For many years dairy scientists have induced lactation by means of direct injection of estrogen and progesterone. A new advance allows to improve the effectiveness of this treatment in dairy goats thanks to reserpine, a prolactin releasing agent

Stagnation-Point Flow Towards a Heated Porous stretching Sheet Through a Porous Medium with Thermal Radiation and Variable Viscosity

An analysis is made for the steady two-dimensional stagnation-point flow in a porous medium of an incompressible viscous fluid towards a permeable stretching surface with variable viscosity and thermal radiation. The viscosity of the fluid is assumed to be an inverse linear function of the fluid temperature. The stretching velocity and the surface temperature are assumed to vary linearly with the distance from the stagnation point. The governing equations for the problem where changed to dimensionless ordinary differential equations using scaling group of transformations. The transformed governing equations in the present study were solved numerically by using Rung-Kutta and Shooting method. Favorable comparison with previously published work is performed. A comparison between the analytical and numerical solutions has been included. The numerical solutions are presented to illustrate the influence of the various values of the ratio of free stream velocity and stretching velocity, the viscosity variation parameter and the porosity parameter. These effects of the different parameter on the velocity and temperature profiles in the boundary layer as well as the coefficient of heat flux and shearing  stress at the surface are presented graphically to show interesting aspects of the solution

Sublytic Terminal Complement Components Induce Eryptosis in Autoimmune Haemolytic Anaemia Related to IgM Autoantibodies

BACKGROUND/AIMS: Eryptosis, the suicidal death of red blood cells (RBCs), is characterized by phosphatidylserine (PS) exposure at the cell surface. It can be catalysed by a variety of abnormal conditions and diseases. Until now, the many questions surrounding the physiology and pathophysiology of eryptosis have not been sufficiently answered. Recently, we demonstrated IgM and IgA autoantibodies (aab) to induce PS exposure on circulating RBCs of patients with autoimmune haemolytic anaemia (AIHA). However, it remained unclear how these aab lead to eryptosis. METHODS: Serum and plasma samples from patients with clinically relevant AIHA of cold type were used to induce eryptosis in O RBCs. Serum containing fresh complement from healthy donors, antibodies to complement component, and complement factor depleted sera were added to examine the influence of the complement on PS-exposure. RBC bound annexin V PE were analysed by flow cytometry. RESULTS: Eryptosis related to IgM aab was found to be dependent on complement activation and could be effectively inhibited by EDTA, serum heat inactivation and anti-C5. PS exposure increased with sequential activation of the sublytic terminal complement components C5b6, C5b-7 and was most significant at the C5b-8 stage. A decrease was observed following the formation of the lytic membrane attack complex C5b-9, either because of lysis of eryptotic RBCs or because of inhibition of eryptosis by C9. CONCLUSION: Our findings reflect new aspects on RBC destruction in AIHA as well the impact of the terminal complement complexes on the RBC membrane. The striking differences to nucleated cell apoptosis may even have physiological meaning of RBC acting as a buffer of the complement system

Data-driven modeling of smart builiding energy management

Buildings consume approximately 40% of energy in total, which contributes negatively to the environment. Building Energy Management Systems(BEMS) have been used to monitor energy consumption and increase usage efficiency. In this study, the components and importance of BEMS are emphasized. The data from the management systemoftheChamchuri5building in Chula long korn University, Thailand, were used as a template for data-driven modeling for energy usage in smart buildings to analyze the patterns of energy consumption. Using multilevel modeling on theChamchuri5 building ,the main factors that consume energy on a macro and micro level are analyzed .Energy variation between zones and floors was spotted

Structural Magnetic and Electrical Properties Of La0.67ca0.33mn03 Perovskite Synthesized Via Conventional and Co-Precipitation Methods

The structural, magnetic and electrical properties of lanthanum manganites having a nominal composition of Lao67C~.33Mn0s3y nthesized via co-precipitation method (COP) following sintering treatments at temperature ranging between 1100°C and 1350°C are reported. XRD pattern showed the monophasic orthorhombic structure of the sample sintered within the above temperature range for a sintering period of 24 hours. The SEM micrographs showed that the grains are well grown and clear grain boundaries are observed. The grain size increased significantly form 1.7pm to 10.3pm as the sintering temperature increases and were well compacted. Large grains growth with layered features is observed in samples sintered at higher temperature. Ferromagneticparamagnetic phase transition were observed in the f-temperature curves for all the sintered samples. The Curie temperature, T, shifts to lower temperature as the sintering temperature, Ts increases. All the samples show the typical ferromagnetic-paramagnetic phase transition, Tc in the range 267.9 K-259.7 K. The transport properties show the transition of semiconducting to metallic conductivity at Tp, the transition occurs within the range 276 K - 288 K which is higher compared with the data reported earlier. Based on the semiconducting model, Ln(R) oc (- E, /K,T) it was observed that the Activation energy, E, value ranges from 100.40 to 118.73 meV. The colossal magnetoresistance effect appears at low temperature and the highest value of CMR effect was observed at temperature approaching Tp. The highest CMR value was observed near the insulatormetal transition. The maximum MR with a value of -68.2% for H = 1.06 T is obtained in the sample prepared at 1 200°C. The specimens of L a 0 . ~ ~ C a 0 ~p~rehpahre0d~ v ia COP method were compared to the specimen prepared by Conventional Powder method (CPM) for samples sintered at 1300°C. XRD spectrum for the samples exhibit orthorhombic distorted and single-phase perovskite structures. The Curie temperature, Tc and the metal-insulator transition temperature, Tp were obtained by ac susceptibility and four- point probe techniques. The results showed that Tc and Tp were 260 K and 276 K respectively for the COP specimen, which is higher than the results obtained by specimen prepared by CPM with Tc and Tp 245 K and 246 K respectively. These results are due to the high chemical homogeneity and high density for the COP specimen as compared to the CPM specimen. The CMR for the (COP) specimen is observed near the insulator- metal transition with the value of - 56% for H = 1.06 T while for the CPM the CMR value of -34

Remediation of Pesticide-Polluted Water Using Ozonation as a Safe Method

The effectiveness of ozone to remove the organic compound chloropyrifos or cypermethrin from water at the two different levels of 1 and 2 ppm for each and different contact times was studied The recovered amounts of chloropyrifos or cypermethrin were extracted based on the solid phase extraction SPE method and then analyzed by GC-MS The results demonstrated that the removal of these organic compounds by ozone increased with increasing the contact time The removal percentages of chloropyrifos following ozone bubbling for different periods of 15 30 45 and 60 minutes at room temperature were 10 5 96 3 97 4 and 98 5 in case of samples fortified at the level of 1 ppm while they were 79 6 93 9 94 7 and 96 1 at the level of 2 ppm respectively In case of cypermethrin the removal percentages were 68 6 90 5 97 and 99 2 at 1 ppm level whereas they found to be 30 5 50 84 7 and 92 at 2 ppm respectively Kinetic studies revealed that chloropyrifos and cypermethrin were found to be easily removed from water by ozone treatmen