The utilization and incorporation of glass fiber-reinforced plastics (GFRP) in structural applications and architectural constructions are progressively gaining prominence. Therefore, this paper experimentally and numerically investigates the use of GFRP I-beams in conjunction with concrete slabs to form composite beams. The experimental design incorporated 2600 mm long GFRP I-beams which were connected compositely to concrete slabs with a 500 mm width and 80 mm thickness. The concrete slabs are categorized into two groups: concrete slabs cast using normal-strength concrete (NSC), and concrete slabs prepared using high-strength concrete (HSC). Various parameters like the type of concrete (normal and high-strength concrete), type of stiffeners bonded to the composite section (bolt–epoxy or bolt only), and inclusion of corrugated metal sheets were investigated. To obtain the full shear connection between the GFRP I-sections and concrete slabs, two rows of shear connectors in the form of bolts were utilized. These shear connectors were erected to the top flange of the GFRP I-sections to compositely connect between the GFRP I-beams and the concrete slabs as well as the corrugated metal sheets. The strengthening of the shear webs of GFRP I-beams with GFRP T-section stiffeners resulted in an enhancement in the flexural and shear strength. The failure loads in the case of the bolt–epoxy connection for the stiffeners were 8.2% and 10.0% higher than those in the case of bolt only when the concrete compressive strengths were 20.1 MPa and 52.3 MPa, respectively. Moreover, the effect of the concrete compressive strength was vital where the failure loads increased by 79.9% and 77.1% when HSC was used instead of NSC for the cases of bolt–epoxy and bolt only, respectively. The epoxy adhesive used in conjunction with mechanical connectors, specifically bolts, resulted in sufficient composite action and delayed shear failure within the web of the GFRP beam. For the specimens with bolt–epoxy connection, strain levels in the concrete slabs were consistently higher than in the other specimens with bolts alone at the same loading level. The concrete slabs integrated with HSC registered strain levels that were 20.0% and 21.8% greater for bolt–epoxy and bolt-only connections, respectively, when compared to those using normal-strength concrete (NSC). This discrepancy can likely be credited to the enhanced composite interaction between the concrete slabs and the GFRP I-beams. In addition, ABAQUS software (version 6.2) was used to develop FE models to analyze the tested composite beams and provide a parametric study using the verified models.
An electrochemical sensor based on manganese dioxide nanorodMnO2and Graphene oxide (GO) functionalized with 4-amino, 3-substituted 1H, 1, 2, 4 Triazole 5(4H) thion (FGO)/MnO2Nanocompositewas developed for voltammetric determination of Tetracycline (TET).The working electrode WE of SPCE was modified bya drop casting method. X-ray powder diffractometer (XRD), scanning electron microscopy (SEM) and FT-IR were employed to characterize the synthesized FGO/MnO2. The determination of TET at the modified electrode was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in the phosphate buffer solution (PBS).TET show sharp increase in the oxidation peaks in the pH 2.Voltammetric characteristics of TET (Epa, Ipa) were estimate
... Show MoreThe research aims:
1- To know the intemperance use of the internet by the University's students.
2- To know the differences with a statistical indication in the intemperance use of the internet after the gender's inconstant ( Males-females).
3- To know the differences with a statistical indication in the intemperance use of the internet after the Major's inconstant ( scientific- humanistic)
This current research restricts a sample of the university students for both sexes.
Theoretical frame:
The research viewed several theories that explains intemperance use of the internet & the results.
Research measures :
1- Research has been adapted the scale ( Internet use) which was prepared by the Moroccan researcher (
The aim of the current research is to measure the sense of coherence among individuals with physical disabilities. The researcher adopted a scale of (29) paragraphs spread over three domains designed by Antonovski (1993) to measure the sense of coherence. A sample of (210) disabled individuals was chosen randomly to collect the required data. The data were analyzed using the statistical package for social sciences (SPSS). The result showed a lack of sense of coherence among the sample.
Background: disturbed physiological rhythm of blood pressure in preeclampsia is a common finding. The role of oxidative stress in pathogenesis of preeclampsia is well accepted. Melatonin is a powerful free radical scavenger so it's rapidly consumed by enhanced reactive oxygen species in preeclampsia causing non-dipping in blood pressure.Objective: To evaluate the change in plasma melatonin levels in patients with preeclampsia and its relationship with blood pressure.Patients and methods: In this prospective case control study a total of 40 primigravidae pregnant women were recruited during the period of 11 months between August 2015 and August 2016 in Baghdad teaching hospital, medical city, Iraq, divided into two groups:First group
... Show MoreBackground: the coronavirus leads to upper respiratory tract-associated manifestations like nasal congestion, sore throat, and smell disorder
Objectives: To reveal the impact of COVID-19 pandemic on otolaryngology symptoms using our daily medical practice.
Subject and Methods: A cross-sectional study that was carried on in the isolation wards at Al-Kindy and Al-Nu’man Teaching Hospitals during three months from the 1st of Jun. till the end of Aug. 2020. It included 1270 patients who were diagnosed with COVID-19 infection seen in the ENT consultation clinic and admitted to the isolation wards.
Results: Otolaryngological manifestations were shown
... Show Morethe physical paraneters of oxadizole derivaties as donor molecules have been measured the charge transfer and methanol as solvent have been estimated from the electonic spectra
Background. Nocturnal enuresis (NE), defined as intermittent involuntary urine leakage during sleep, affects approximately 16% of children at age 5 and 10% at age 7, with prevalence declining with age. Aim. To evaluate the urodynamic features of patients with non-monosymptomatic nocturnal enuresis (NMNE). Methods. This cross-sectional study was conducted from June 2015 to September 2020 in a surgical subspecialty hospital within a major medical city complex, including 237 patients. Eligible patients were older than seven years, diagnosed with NMNE, and had refractory enuresis, defined as persistent symptoms despite at least six months of continuous medical treatment. All patients underwent a detailed history, bladder diary review, c
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