Punching shear behavior of fiber reinforced polymers reinforced concrete flat slabs: experimental study

This paper presents the results of a two-phase experimental program investigating the punching shear behavior of fiber reinforced polymer reinforced concrete (FRP RC) flat slabs with and without carbon fiber reinforced polymer (CFRP) shear reinforcement. In the first phase, problems of bond slip and crack localization were identified. Decreasing the flexural bar spacing in the second phase successfully eliminated those problems and resulted in punching shear failure of the slabs. However, CFRP shear reinforcement was found to be inefficient in enhancing significantly the slab capacity due to its brittleness. A model, which accurately predicts the punching shear capacity of FRP RC slabs without shear reinforcement, is proposed and verified. For slabs with FRP shear reinforcement, it is proposed that the concrete shear resistance is reduced, but a strain limit of 0.0045 is recommended as maximum strain for the reinforcement. Comparisons of the slab capacities with ACI 318-95, ACI 440-98, and BS 8110 punching shear code equations, modified to incorporate FRP reinforcement, show either overestimated or conservative results

Raman excitation spectroscopy of carbon nanotubes: effects of pressure medium and pressure

Raman excitation and emission spectra for the radial breathing mode (RBM) are reported, together with a preliminary analysis. From the position of the peaks on the two-dimensional plot of excitation resonance energy against Raman shift, the chiral indices (m, n) for each peak are identified. Peaks shift from their positions in air when different pressure media are added - water, hexane, sulphuric acid - and when the nanotubes are unbundled in water with surfactant and sonication. The shift is about 2 - 3 cm-1 in RBM frequency, but unexpectedly large in resonance energy, being spread over up to 100meV for a given peak. This contrasts with the effect of pressure. The shift of the peaks of semiconducting nanotubes in water under pressure is orthogonal to the shift from air to water. This permits the separation of the effects of the pressure medium and the pressure, and will enable the true pressure coefficients of the RBM and the other Raman peaks for each (m, n) to be established unambiguously.Comment: 6 pages, 3 Figures, Proceedings of EHPRG 2011 (Paris

Determination of Hydrazlne Using Potassium Dichromate as Oxidizing Agent

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Pressure coefficients of Raman modes of carbon nanotubes resolved by chirality: Environmental effect on graphene sheet

Studies of the mechanical properties of single-walled carbon nanotubes are hindered by the availability only of ensembles of tubes with a range of diameters. Tunable Raman excitation spectroscopy picks out identifiable tubes. Under high pressure, the radial breathing mode shows a strong environmental effect shown here to be largely independent of the nature of the environment . For the G-mode, the pressure coefficient varies with diameter consistent with the thick-wall tube model. However, results show an unexpectedly strong environmental effect on the pressure coefficients. Reappraisal of data for graphene and graphite gives the G-mode Grueuneisen parameter gamma = 1.34 and the shear deformation parameter beta = 1.34.Comment: Submitted to Physical Review

Current Status and Utilization of Oral and Dental Health Services in Gezira State (2005-2009)

 Objective:  This study aimed to assess the status of the present dental and oral health services   in the Gezira state.  Methods: The study areas comprise of three clusters: urban, suburban and rural. Five study sites in the urban area, four sites in suburban area around Wad Medani and 12 sites in the rural area were chosen from the six localities of Gezira State . The households study sample was as follows: 100 in the urban area, 108 in the rural area and 52 in the suburban area. The study tools were direct pre-coded questionnaires, household survey and observation checklist. The procedure involved household interview to evaluate dental  status of dental health professionals, equipment and materials in order to assess dental health services. Descriptive statistics was used to analyze and present the data. The SPSS Statistical Programme using Microsoft Windows was used. Results: This result revealed absolute lack of dental services in the rural and relative lack of services in suburban areas. The present unit is old and most of them were incomplete and not functioning. This was the reason that some of rural and suburban populations seek oral health services in Wad Medani health institutions. Most of the patients irrespective of their residence preferred treatment at private dental clinics because they expect better care due to good facilities Recommendation: Establishing new dental units with good facilities distributed in different localities and rehabilitation of dental units provided to Elhasaheisa and Elmanagil dental departments with equipments and dental specialties to become specialized dental hospitals to cover the population needs and demand dental services for the surrounding areas

Investigating the association between strategic and pathological gambling behaviors and substance use in youth: Could religious faith play a differential role?

Objectives: This study investigated the link between gambling behaviors and the use of alcohol, drugs, and nonprescribed prescription medications, while exploring the moderating role of distinct religious faiths. Methods:: In 2010, 570 students from the American University of Beirut completed a self-reported, anonymous English questionnaire, which included lifetime gambling and past-year substance use measures. Results: Half (55%) were lifetime gamblers, of whom, 12% were probable pathological gamblers. About 60% were strategic gamblers. Lifetime gamblers were more than twice as likely as nongamblers to report past-year illegal drug use and alcohol abuse. Probable pathological gamblers were also more than four times as likely as nongamblers to report nonmedical prescription drug use, illegal drug use, and alcohol abuse. Compared to nonstrategic gamblers, strategic gamblers had more than three times the odds of illegal drug and cigarette use. The link between alcohol abuse and gambling was stronger among Christians than Muslims. Conversely, Muslims were more likely to report the co-occurrence of various gambling behaviors (lifetime, probable pathological, and strategic gambling) with both illegal drug use and cigarette use. Conclusions: Gambling and substance use behaviors were strongly linked in this sample of youth from Lebanon, corroborating the evidence from North America. Particularly novel are the co-occurrence of pathological gambling and nonmedical prescription drug use and the potential differential role of religion

Acute ST-segment elevation myocardial infarction in a young patient with essential thrombocythemia: a case with long-term follow-up report

Essential thrombocythemia (ET) is a neoplastic proliferation of mature myeloid cells - in particular, megakaryocytes - leading to persistently elevated platelet count. Usual clinical presentation is related to an increase in the risk of hemorrhage and/or thrombosis. Management of ET consists of antiplatelet therapies - mainly aspirin and cytoreductive therapies. Coronary involvement in patients with ET is rare. The optimal treatment strategies for ET patients presenting with acute myocardial infarction remains unclear. Acute interventions like intracoronary thrombolytic therapy, angioplasty, and coronary-artery bypass grafting have been reported in such patients. However, several questions remain unanswered about the acute and long-term management of these patients. Herein, we report the case of a 47-year-old female who presented with acute myocardial infarction as the first clinical sign of ET, and also present the long-term follow-up of this patient

On the Initial Singularity Problem in Two Dimensional Quantum Cosmology

The problem of how to put interactions in two-dimensional quantum gravity in the strong coupling regime is studied. It shows that the most general interaction consistent with this symmetry is a Liouville term that contain two parameters $(\alpha, \beta)$ satisfying the algebraic relation $2\beta - \alpha =2$ in order to assure the closure of the diffeomorphism algebra. The model is classically soluble and it contains as general solution the temporal singularity. The theory is quantized and we show that the propagation amplitude fall tozero in $\tau =0$. This result shows that the classical singularities are smoothed by quantum effects and the bing-bang concept could be considered as a classical extrapolation instead of a physical concept.Comment: 9pp, Revtex 3.0. New references added. To appear in Phys. Rev.