Influence of EBR on the structural resistance of RC slabs under quasi-static and blast loading: Experimental testing and numerical analysis

Flexural strengthening of reinforced concrete (RC) structures with externally bonded reinforcement (EBR) using carbon fibre-reinforced polymers (CFRP) has in recent years received increased interest from specialists, particularly when dealing with protective structures against terrorist or accidental blast loading. Although a significant number of studies have been conducted on the failure modes of the bonded interface for quasi -static conditions, there is still limited published research on the effects of blast loading. In this paper, RC slabs externally strengthened with CFRP are tested in three-point bending as well as subjected to blast loading. The behaviour of the tested specimens under both loading regimes is evaluated with special focus on the mechanisms that lead to the disruption of the CFRP. It was found that the debonding of the CFRP was caused, in both cases, by the fracture and separation of a thin layer of concrete in the near vicinity of the bonded interface. However, the mechanisms that lead to this failure differ. A numerical model was developed and simulations performed using the finite element (FE) code LS-DYNA to investigate the validity of commonly used simplifications on the modelling of the interface in both cases. It was found that although the modelling technique used to represent the disruption of CFRP under quasi-static conditions provide accurate results, it does not return accurate predictions of the debonding of CFRP under blast loading

Penile hair coil strangulation of the child

AbstractWe report the case of a child with a delayed presentation of penile strangulation with a coil of hair that resulted in a complete transection of the urethra. Hair coil strangulation of the penis is uncommon. It is also known as penile Tourniquet syndrome. It has been reported with circumcised and uncircumcised penises and it can lead to serious complications like the amputation of the penis. Prompt diagnosis and treatment are necessary to prevent complications

Genetic, serological and biochemical characterization of Leishmania tropica from foci in northern Palestine and discovery of zymodeme MON-307

Background Many cases of cutaneous leishmaniasis (CL) have been recorded in the Jenin District based on their clinical appearance. Here, their parasites have been characterized in depth. Methods Leishmanial parasites isolated from 12 human cases of CL from the Jenin District were cultured as promastigotes, whose DNA was extracted. The ITS1 sequence and the 7SL RNA gene were analysed as was the kinetoplast minicircle DNA (kDNA) sequence. Excreted factor (EF) serotyping and multilocus enzyme electrophoresis (MLEE) were also applied. Results This extensive characterization identified the strains as Leishmania tropica of two very distinct sub-types that parallel the two sub-groups discerned by multilocus microsatellite typing (MLMT) done previously. A high degree of congruity was displayed among the results generated by the different analytical methods that had examined various cellular components and exposed intra-specific heterogeneity among the 12 strains. Three of the ten strains subjected to MLEE constituted a new zymodeme, zymodeme MON-307, and seven belonged to the known zymodeme MON-137. Ten of the 15 enzymes in the profile of zymodeme MON-307 displayed different electrophoretic mobilities compared with the enzyme profile of the zymodeme MON-137. The closest profile to that of zymodeme MON-307 was that of the zymodeme MON-76 known from Syria. Strains of the zymodeme MON-307 were EF sub-serotype A2 and those of the zymodeme MON-137 were either A9 or A9B4. The sub-serotype B4 component appears, so far, to be unique to some strains of L. tropica of zymodeme MON-137. Strains of the zymodeme MON-137 displayed a distinctive fragment of 417 bp that was absent in those of zymodeme MON-307 when their kDNA was digested with the endonuclease RsaI. kDNA-RFLP after digestion with the endonuclease MboI facilitated a further level of differentiation that partially coincided with the geographical distribution of the human cases from which the strains came. Conclusions The Palestinian strains that were assigned to different genetic groups differed in their MLEE profiles and their EF types. A new zymodeme, zymodeme MON-307 was discovered that seems to be unique to the northern part of the Palestinian West Bank. What seemed to be a straight forward classical situation of L. tropica causing anthroponotic CL in the Jenin District might be a more complex situation, owing to the presence of two separate sub-types of L. tropica that, possibly, indicates two separate transmission cycles involving two separate types of phlebotomine sand fly vector

Numerical prediction of the dynamic response of prestressed concrete hollow core slabs under blast loading

This paper investigates the use and accuracy of finite element simulations by means of LS-DYNA of reinforced concrete hollow core slabs with a compression layer, simply supported and subjected to blast loading. The aim of this paper is to explain how to develop a numerical model, in order to predict the maximum deflection and crack distribution. Parametric studies related to hourglass energy, erosion value and the material model of the concrete are performed in order to evaluate the effects on the dynamic response of the hollow core slabs. This numerical analysis is completed by experimental tests for validation purposes

Un nouveau variant enzymatique de

Pour la première fois, l’agent pathogène de la leishmaniose cutanée du Nord de l’Algérie est rapporté à Leishmania infantum s.l. Il s’agit d’un variant enzymatique original (zymodème 24) différant pour deux électromorphes du variant isolé en France (zymodème 11), dans le même type de lésion. Jusqu’à ce jour, les zymodèmes dermotropes d’Algérie et de France n’ont pas été observés dans la leishmaniose viscérale méditerranéenne

Écologie des leishmanioses dans le sud de la France

Pour la première fois deux souches de Leishmanies, isolées en Cévennes d’une population naturelle de Phlebotomus ariasi, sont identifiées par la méthode enzymatique. Elles se rapportent toutes deux au zymodème 1, caractéristique de Leishmania infantum s. st

Load-Displacement Assessment of One-Way Reinforced Concrete (RC) Slabs Externally Strengthened Using CFRP Strips under Blast Loads

Dynamic behaviour of Reinforced Concrete (RC) structures can be assessed using a Single-Degree-of-Freedom (SDOF) approach. Such a method is highly dependent on the resistance curve of the structure which is generally represented by a bilinear elasto-perfectly-plastic approximation. This approximation might lead to erroneous results when it refers to the use of externally bonded Fibre Reinforced composites for flexural capacity upgrade of Reinforced Concrete (RC), mainly when the concrete-to-FRP interface failure is to be included. One-way slabs are experimentally and numerically investigated in this study in a 3-point flexural configuration. Assessment on the load-displacement behaviour of a reference specimen and its retrofitted counterpart is performed. Special attention is given to the behaviour of the structure after the concrete-to-FRP failure. Comparison is made between experimental and numerical results and a good agreement is obtained. A complementary analytical study based on the SDOF method is conducted to understand the influence of several resistance curves on the overall displacement of the same structure when subjected to different pressure-impulse combinations