The aim of this investigation is to evaluate the experimental and numerical effectiveness of a new kind of composite column by using Glass Fiber‐Reinforced Polymer (GFRP) I‐section as well as steel I‐section in comparison to the typical reinforced concrete one. The experimental part included testing six composite columns categorized into two groups according to the slenderness ratio and tested under concentric axial load. Each group contains three specimens with the same dimensions and length, while different cross‐section configurations were used. Columns with reinforced concrete cross‐section (reference column), encased GFRP I‐section, and encased steel I‐section were adopted in each group. The modes of failure, axial loads, axial displacements, and strains in the concrete were the main experimental results. The observed typical mode of failure was a compression failure, and the concrete cover was splitting mostly at the column mid‐height. The load‐carrying capacities of the long composite specimens with the encased GFRP and steel I‐sections increased by approximately 11.2% and 15.8%, respectively, compared to the control column. However, these improvements were 12.0% and 24.3% in the case of short composite columns. In short columns, the failure load increased by 11% in comparison to the long ones. Numerical simulations were developed to verify the experimental results. The FE results evince good agreement with the experimental results in terms of the ultimate axial loads, deformations, and modes of failure.
In present work an investigation for precise hole drilling via continuous wave (CW) CO2 laser at 150 W maximum output power and wavelength 10.6 μm was achieved with the assistance of computerized numerical controlled (CNC) machine and assist gases. The drilling process was done for thin sheets (0.1 – 0.3 mm) of two types of metals; stainless steel (sst) 321H, steel 33 (st). Changing light and process parameters such as laser power, exposure time and gas pressure was important for getting the optimum results. The obtained results were supported with computational results using the COMSOL 3.5a software code.
The studies on unbonded post-tensioned concrete members strengthened with Carbon Fiber Reinforced Polymers (CFRPs) are limited and the effect of strengthening on the strain of unbonded pre-stressed steel is not well characterized. Estimating the flexural capacity of unbound post-tensioned members using the design methodology specified in the design guidelines for FRP strengthening techniques of bonded post-tensioned members does not provide a reliable evaluation. This study investigates the behavior of unbonded post-tensioned concrete members with partial strand damage (14.3% and 28.6% damage) and strengthened with CFRP laminates using a near-surface mounted technique with and without U-wrap anchorages. The experimental results show
... Show MoreBackground: This study aimed to determine whether there is a relationship among the bite force with facial dimensions and dental arches in a sample of Iraqi adults with Class I skeletal and dental relations. Materials and methods: Forty dental students (20 males and 20 females) were selected under certain criteria. For those individuals, dental impressions, frontal facial photographs and maximum bite force at molar and incisor regions were taken. The dental arches widths and facial dimensions were measured using the AutoCAD program 2007, while the bite force was determined using special device. Descriptive statistics for the measured variables were performed and gender difference was determined using independent sample t-test, while the rel
... Show MoreBackground: This study evaluated the influence of different fiber formulations incorporation in resin composite on cuspal deflection (CD) of endodontically-treated teeth with mesio-occluso-distal (MOD) cavities. Materials and Methods: Thirty-two freshly extracted maxillary premolar teeth received MOD cavity preparation followed by endodontic treatment using single cone obturation technique, and divided into: Group I: direct composite resin only using a centripetal technique, Group II: direct composite resin with short fiber-reinforced composite (everX Flow), Group III: direct composite resin with leno wave ultra-high molecular weight polyethylene (LWUHMWPE) fibers placed on the cavity floor, and Group IV: direct composite resin with LWUHMWP
... Show MoreThe study aimed to prepare a nanocapsules formulation from the acetonic extract of Moringa oleifera leaves, using polymeric capsules, and test its toxicity against the third instar larvae of Culex pipiens mosquitoes. The leaf extract was prepared using acetone as a solvent, and the nano polymeric capsules were prepared using the synthetic polymer polyethylene glycol 4000. The results showed the successful preparation of nano polymeric capsules from the leaf extract, with an average particle size of 259.2 nm, and a nanocapsule diameter of 263.83 nm, as determined by DLS and SEM analysis, respectively. The toxicity results indicated that the nano polymeric capsules of the leaf extract exhibited higher mortality rates, reaching 97.6% a
... Show MoreThe response of floating stone columns of different lengths to diameter ratio (L/D = 0, 2, 4, 6, 8, and 10) ratios exposed to earthquake excitations is well modeled in this paper. Such stone column behavior is essential in the case of lateral displacement under an earthquake through the soft clay soil. ABAQUS software was used to simulate the behavior of stone columns in soft clayey soil using an axisymmetric finite element model. The behavior of stone column material has been modeled with a Drucker-Prager model. The soft soil material was modeled by the Mohr-Coulomb failure criterion assuming an elastic-perfectly plastic behavior. The floating stone columns were subjected to the El Centro earthquake, which had a magnitude of 7.1 an
... Show MoreDarifenacin hydrobromide is a selective ?3 receptor antimuscarinic drug and it is used in the management of urinary frequency, urgency, and incontinence in detrusor instability. It slightly soluble in water, undergoes extensive hepatic first-pass metabolism and has short elimination half-life (3–4 hours). Therefore, It has low bioavailability (15.4 % - 18.6 %). Darifenacin hydrobromide loaded NLCs were formulated by emulsification sonication using different ratios of solid lipid to liquid lipid, different types of surfactants, and different concentration of surfactants. Formula sixteen was considered as an optimized formula based on its particle size, PDI, zeta potential and entrapment efficiency. Formula sixteen subjected t
... Show MoreThe basic analytical formula for particle-hole state densities is derived based on the non-Equidistant Spacing Model (non-ESM) for the single-particle level density (s.p.l.d.) dependence on particle excitation energy u. Two methods are illustrated in this work, the first depends on Taylor series expansion of the s.p.l.d. about u, while the second uses direct analytical derivation of the state density formula. This treatment is applied for a system composing from one kind of fermions and for uncorrected physical system. The important corrections due to Pauli blocking was added to the present formula. Analytical comparisons with the standard formulae for ESM are made and it is shown that the solution reduces to earlier formulae providing m
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