This study expands the state of the art in studies that assess torsional retrofit of reinforced concrete (RC) multi-cell box girders with carbon fiber reinforced polymer (CFRP) strips. The torsional behavior of non-damaged and pre-damaged RC multi-cell box girder specimens externally retrofitted by CFRP strips was investigated through a series of laboratory experiments. It was found that retrofitting the pre-damaged specimens with CFRP strips increased the ultimate torsional capacity by more than 50% as compared to the un-damaged specimens subjected to equivalent retrofitting. This indicated that the retrofit has been less effective for the girder specimen that did not develop distortion beforehand as a result of pre-loading. From experimental observations, when the girder specimen was cracked and the transverse steel reinforcement bars started straining, the CFRP strips started to work more effectively and contributed together with the transverse steel reinforcement to resist torsion load. Additionally, Finite Element (FE) simulations were developed using Abaqus to model the torsional behavior of the retrofitted girders, the results of which were validated with the experimental data. With the numerical model, the effect of concrete compressive strength, transverse reinforcement spacing, and CFRP strip spacing were examined. The effectiveness of the CFRP strips in enhancing the torsional strength of the girder was found to increase with increasing the spacing between the transverse reinforcement.
In this work, a novel technique to obtain an accurate solutions to nonlinear form by multi-step combination with Laplace-variational approach (MSLVIM) is introduced. Compared with the traditional approach for variational it overcome all difficulties and enable to provide us more an accurate solutions with extended of the convergence region as well as covering to larger intervals which providing us a continuous representation of approximate analytic solution and it give more better information of the solution over the whole time interval. This technique is more easier for obtaining the general Lagrange multiplier with reduces the time and calculations. It converges rapidly to exact formula with simply computable terms wit
... Show MoreLocal and global bifurcations of food web model consists of immature and mature preys, first predator, and second predator with the current of toxicity and harvesting was studied. It is shown that a trans-critical bifurcation occurs at the equilibrium point
Esculin (ESCN) is used in the pharmaceutical industry with intravenous effect, stimulant and anti-inflammatory capillaries, like vitamin P. It is a significant component of many anti-inflammatory remedies such as esqusan, esflazid and anavenol [14]. It is also found in numerous other remedies available in the market such as proctosone, anustat, and ariproct.
To determine experimental conditions, to elucidate retention behavior of esculin in HILIC mode. Moreover, to suggest new ways to separate and determinate esculin in ointments.
Two hydrophilic c
A novel ligand ((1E)-(2-(4-fluorobenzylidene)amino)methyl) phenyl)diazenyl)-1,3,7-trimethyl-3,7-dihydro-1H-purine-2,6-dione (4-FADPD) was synthesized via the azotization reaction of 2-aminobenzylamine with caffeine, and the resultant compound was condensed with 4-fluorobenzaldehyde to form a newly azo-Schiff base ligand. Its complexes with Cu(II), Ag(I), and Au(III) were synthesized. The results of multi-identifications, including XRD, elemental analysis (C.H.N), UV-vis spectroscopy, FTIR, and 1H-NMR, were used to propose the suggested structures using molar conductivity measurements. These data were utilized to propose appropriate geometric configurations for all complexes. The azo-Schiff base ligand coordinates toward the Cu(II) i
... Show MoreBearing capacity of a concrete pile in fine grained cohesive soils is affected by the degree of saturation of the surrounding soil through the contribution of the matric suction. In addition, the embedded depth and the roughness of the concrete pile surface (expressed as British Pendulum Number BPN) also have their contribution to the shear strength of the concrete pile, consequently its bearing capacity. Herein, relationships among degree of saturation, pile depth, and surface roughness, were proposed as a mathematical model expressed as an equation where the shear strength of a pile can be predicted in terms of degree of saturation, depth, and BPN. Rel
... Show MoreAn experimental investigation of natural convection heat transfer from an isothermal horizontal,vertical and inclined heated square flat plates with and without circular hole, were carried out in two cases, perforated plates without an impermeable adiabatic hole "open core" and perforated plates with an impermeable adiabatic hole "closed core" by adiabatic plug. The experiments covered the laminar region with a range of Rayleih number of (1.11x106 ≤RaLo≤4.39x106 ), at Prandtle number (Pr=0.7). Practical experiments have been done with variable inclination angles from horizon (Ф=0o ,45o,90o,135oand 180o),facing upward (0o≤Ф<90o), and downward (90o
≤Ф<180o). The results showed that the temperature gradient increases whi