Towards efficient structural and serviceability design of high-strength concrete t-beams

A total of 10 HSC T-beams having a total length of 1700 mm, web breadth of 100 mm, height of 250 mm, and different flange dimensions, were experimentally tested until failure. The studied parameters were; flange dimensions, transverse reinforcement ratio, and longitudinal reinforcement ratio of the beam. A numerical model was developed to predict the flexural behaviour of the tested beams. The results indicated that increasing breadth, depth, and flange reinforcement ratio led to reduction in the overall deflection, and enhancment of the ultimate load capacity. An empirical equation, developed earlier by the authors for predicting effective moment of inertia for HSC T beams, was used successfully to predict load-deflection relationships for the studied beams. Comparisons were carried out between the load-deflecion curves predicted by the numerical model, those predicted by this equation, and those predicted by Branson equation which is currently used in the design codes. It was found that there was a close agreement between the experimental results, numerical results and those obtained by the authors’ equation. This research highlights the need for updating the Branson equation used in the design codes for deflection design of HSC T beams by adopting the equation proposed by the authors

Towards efficient structural and serviceability design of high-strength concrete T-beams

A total of 10 HSC T-beams having a total length of 1700 mm, web breadth of 100 mm, height of 250 mm, and different flange dimensions, were experimentally tested until failure. The studied parameters were; flange dimensions, transverse reinforcement ratio, and longitudinal reinforcement ratio of the beam. A numerical model was developed to predict the flexural behaviour of the tested beams. The results indicated that increasing breadth, depth, and flange reinforcement ratio led to reduction in the overall deflection, and enhancment of the ultimate load capacity. An empirical equation, developed earlier by the authors for predicting effective moment of inertia for HSC T beams, was used successfully to predict load-deflection relationships for the studied beams. Comparisons were carried out between the load-deflecion curves predicted by the numerical model, those predicted by this equation, and those predicted by Branson equation which is currently used in the design codes. It was found that there was a close agreement between the experimental results, numerical results and those obtained by the authors’ equation. This research highlights the need for updating the Branson equation used in the design codes for deflection design of HSC T beams by adopting the equation proposed by the authors

Rotary Friction Welding Versus Fusion Butt Welding of Plastic Pipes – Feasibility and Energy Perspective

According to the Plastics Pipe Institute, butt fusion is the most widely used method for joining lengths of PE pipe and pipe to PE fittings “by heat fusion” (https://plasticpipe.org/pdf/chapter09.pdf). However, butt-welding is not energy-cognizant from the point of view of a phase-change fabrication method. This is because the source of heating is external (heater plate). The initial heating and subsequent maintenance at relatively high temperature (above 200 C for welding of high-density polyethylene pipe) is energy intensive. Rotary friction welding, on the other hand focuses the energy where and when as needed because it uses electric motor to generate mechanical (spinning) motion that is converted to heat. This work will make the case for friction heating as energy efficient. An initial feasibility study will also be introduced to demonstrate that the resulting welded pipe joints may be of comparable quality to those produced by butt fusion and to virgin PE material

Preventive effect of the flavonoid, quercetin, on hepatic cancer in rats via oxidant/antioxidant activity: molecular and histological evidences

<p>Abstract</p> <p>Background</p> <p>The incidence of hepatocellular carcinoma is increasing in many countries. The estimated number of new cases annually is over 500,000, and the yearly incidence comprises between 2.5 and 7% of patients with liver cirrhosis. The incidence varies between different geographic areas, being higher in developing areas; males are predominantly affected, with a 2:3 male/female ratio</p> <p>Methods</p> <p>Experiments were designed to examine the effect of <it>N</it>-Nitrosodiethylamine (NDEA) as cancer-inducer compound and to confirm the preventive effect of the flavonoid quercetin on hepatocellular carcinoma in rats. Briefly, thirty six male albino rats of Wistar strain were divided into 3 groups: the 1^stgroup was administered NDEA alone (NDEA-treated), the 2^ndgroup was treated simultaneously with NDEA and quercetin (NDEA+Q) and the 3^rdgroup was used as control (CON). Randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) as well as <it>p53</it>-specifi PCR assays were employed to determine genomic difference between treated, and control animals. Histological confirmation as well as oxidant/antioxidant status of the liver tissue was done.</p> <p>Results</p> <p>RAPD analysis of liver samples generated 8 monomorphic bands and 22 polymorphic bands in a total of 30-banded RAPD patterns. Cluster analysis and statistical analyses of RAPD data resulted in grouping control and NDEA+Q samples in the same group with 80% similarity cut-off value. NDEA-treated samples were clustered in a separate group. Specific PCR assay for polymorphism of <it>P</it>⁵³gene revealed a uniform pattern of allele separation in both control and NDEA+Q samples. Quercetin anticancer effect was exhibited in significant decrease of oxidative stress and significant decrease of antioxidant activity. Histopathological studies showed normal liver histology of the NDEA+Q samples. Meanwhile, several cancer-induced features were clearly observable in NDEA-treated samples.</p> <p>Conclusion</p> <p>This paper demonstrated that preventive effect of quercetin on hepatocarcinoma in rats by RAPD-PCR, tracing the effect on <it>p53 </it>gene and by histopathological evidence. Hereby, it was proved that quercetin exerted its preventive effect via decreased oxidative stress and decreased antioxidant activity.</p

SERVICEABILITY BEHAVIOR OF NORMAL AND HIGH-STRENGTH REINFORCED CONCRETE T-BEAMS

Serviceability behavior of Normal Strength Concrete (NSC) and High Strength Concrete (HSC) T-beams was experimentally evaluated. The crack pattern was observed, the effect of flange dimensions (breadth and thickness) on the crack pattern and load-deflection response was evaluated experimentally for 10 beams comprising the two studied groups, NSC and HSC T-beams. The short-term deflections were measured experimentally and predicted empirically under mid-span concentrated loading. It was found that increasing the flange width and thickness resulted in higher loads and lower deflections under service loads to a different extent. Prior to failure, the increment in the maximum loads was up to 22% while the deflection reduced by 31% for NSC and 23% for HSC beams. The available equations for determining the effective moment of inertia (Ie) were reviewed and used in predicting the Ie of the cracked beam. The results were compared with the experimental values (Iexp). The Ie showed a noticeable difference, especially for the HSC T-beams. New equations were proposed in which the tensile reinforcement ratio was considered. Compared with the other available equations, the proposed equations demonstrated a better agreement and repeatability of predicting experimental results studied herein. In addition, the proposed equations were used to predict the Ie for experimentally tested T-beams available in the literature. The proposed models showed a high degree of accuracy

Weak Isospin Violations in Charged and Neutral Higgs Couplings from SUSY Loop Corrections

Supersymmetric QCD and supersymmetric electroweak loop corrections to the violations of weak isospin to Yukawa couplings are investigated. Specifically it involves an analysis of the supersymmetric loop corrections to the Higgs couplings to the third generation quarks and leptons. Here we analyze the SUSY loop corrections to the charged Higgs couplings which are then compared with the supersymmetric loop corrections to the neutral Higgs couplings previously computed. It is found that the weak isospin violations can be quite significant, i.e, as much as 40-50% or more of the total loop correction to the Yukawa coupling. The effects of CP phases are also studied and it is found that these effects can either enhance or suppress the weak isospin violations. We also investigate the weak isospin violation effects on the branching ratio $BR(H^-\to\bar t b)/ BR(H^-\to \bar\nu_{\tau}\tau^-)$ and show that the effects are sensitive to CP phases. Thus an accurate measurement of this branching ratio along with the branching ratio of the neutral Higgs boson decays can provide a measure of weak isospin violation along with providing a clue to the presence of supersymmetry.Comment: 20 pages, 9 figure

Supersymmetric Relations Among Electromagnetic Dipole Operators

Supersymmetric contributions to all leptonic electromagnetic dipole operators have essentially identical diagramatic structure. With approximate slepton universality this allows the muon anomalous magnetic moment to be related to the electron electric dipole moment in terms of supersymmetric phases, and to radiative flavor changing lepton decays in terms of small violations of slepton universality. If the current discrepancy between the measured and Standard Model values of the muon anomalous magnetic moment is due to supersymmetry, the current bound on the electron electric dipole moment then implies that the phase of the electric dipole operator is less than $2 \times 10^{-3}$. Likewise the current bound on $\mu \to e \gamma$ decay implies that the fractional selectron-smuon mixing in the left-left mass squared matrix, \delta m_{\smuon \selectron}^2 / m_{\slepton}^2, is less than $10^{-4}$. These relations and constraints are fairly insensitive to details of the superpartner spectrum for moderate to large $\tan \beta$.Comment: Latex, 38 pages, 2 figure

Mixing of the CP Even and the CP Odd Higgs Bosons and the EDM Constraints

The mixing among the CP even and the CP odd neutral Higgs bosons of MSSM by one loop induced effects in the presence of CP phases is investigated using three different mechanisms to satisfy the EDM constraints, i.e., a fine tuning of phases, a heavy sparticle spectrum, and the cancellation mechanism. It is shown that if a mixing effect among the CP even and the CP odd Higgs bosons is observed experimentally, then it is only the cancellation mechanism that can survive under the naturalness constraint.Comment: 14 pages, Latex and 4figures. A new paragraph is added and few more references. One figure is modified. To appear in Phys. Rev.

Electron and Neutron Electric Dipole Moments in the Focus Point Scenario of SUGRA Model

We estimate the electron and neutron electric dipole moments in the focus point scenario of the minimal SUGRA model corresponding to large sfermion masses and moderate to large $\tan\beta$. There is a viable region of moderate fine-tuning in the parameter space, around $\tan\beta \simeq 5$, where the experimental limits on these electric dipole moments can be satisfied without assuming unnaturally small phase angles. But the fine-tuning constraints become more severe for $\tan\beta > 10$.Comment: 16 pages, LaTeX, 4 postscript figures. Very minor changes made in only a few sentences for clarification. Final version to appear in Phys. Rev.

Incidence of Nosocomial Infection with Nasal Continuous Positive Air Way Pressure Versus Mechanical Ventilation During Treatment of Respiratory Distress in Preterm Neonates

Abstract: Objective: to determine the incidence of nosocomial infections in preterm infants with respiratory distress, if treatment with continuous positive air way pressure (CPAP) compared to treatment with mechanical ventilation (MV). Patients and Methods: Sixty premature neonates admitted to the intensive care unit in Al Galaa Teaching Hospital, in their first day of life suffering from respiratory distress, the infants were divided into two groups, 1 st group include 30 patients supported by CPAP and the 2 nd group include 30 patients who were supported by mechanical ventilation. Blood cultures and early endotracheal cultures were taken in the 1 st day of life from the sixty neonates in both groups then another late endotracheal culture was taken from them in the 5 th day of life. Results: 36.67% of patients in the MV group had +ve blood culture and 63.33% had no growth, while in the CPAP group 16.67% had +ve blood culture and 83.33% showed no growth. Early endotracheal cultures showed +ve growth in 63.33% in the MV groups a 23.33% in the CPAP group. (P=0.002), on the other hand late endotracheal cultures showed +ve growth in 36.67% in the MV group and 16.67% in the CPAP group. Klebsiella was the most frequent organism in all +ve cultures. Conclusion: The incidence of positive infection in blood cultures and endotracheal cultures is higher in the MV group than in the CPAP group. The incidence of klebsiella among the whole population in the two studied groups was higher in MV group more than in the CPAP group in all the cultures. Within the cases having positive cultures, MV patients needed longer duration on ventilation than patients on CPAP (whether the cultures were taken from the blood or endotracheal)