A novel welded demountable shear connector for sustainable steel-concrete composite structures is proposed. The proposed connector consists of a grout-filled steel tube bolted to a compatible partially threaded stud, which is welded on a steel section. This connector allows for an easy deconstruction at the end of the service life of a building, promoting the reuse of both the concrete slabs and the steel sections. This paper presents the experimental evaluation of the structural behavior of the proposed connector using a horizontal pushout test arrangement. The effects of various parameters, including the tube thickness, the presence of grout infill, and the concrete slab compressive strength, were assessed. A nonlinear finite element model was also calibrated against the experimental results, and the validated numerical model was used to extend the validity of the experimental results and to perform further parametric studies. The experimental and numerical results show that the tested connectors have similar stiffness, but higher shear resistance and slip capacity compared with traditional welded shear studs and can be classified as ductile according to Eurocode 4.
Unsaturated polyester was used as a matrix which was filled with different percentages of cobalt ferrite using hand lay-up method. Cobalt ferrite was synthesized using solid state ceramic method with reagent of CoO and Fe2O3. Mechanical properties such tensile strength, Young's modulus and shore D hardness of the composite have been studied. All these properties have increased by 10% with increasing cobalt ferrite contents. Also the thermal properties such thermal conductivity and specific heat capacity are highly increased as the ferrite content increased, while the thermal diffusivity increased by 22 %. On the other hand dielectric strength of composite has been measured which increased by 50% by increasing the cobalt ferrite content.&
... Show MoreThe current study is an attempt to assess the cytogenotoxic potential of the ethanolic extract from the leaves of Borago officinalis on Swiss albino male mice. Young Swiss albino mice were orally administered with leaf ethanolic extract of Borago officinalis. Three mice groups were used using different doses of plant extract (T1: 100, T2: 200, and T3:400 mg\kg) in addition to the control negative group (untreated mice) for 7 days to assess mitotic index or 28 days to assess meiotic index. The results revealed that the extract significantly induced the division of disruptive chromosomal changes in the bone marrow and the mean of abnormality was (3.5±0.47, 4.43±0.83, and 5.83±0.96%) for T1, T2, and T3 re
... Show MoreGenus Salix is among family Salicaceae, distributing in the northern hemisphere. It is represented in Egypt by two species (Salix mucronata and Salix tetrasperma). The classification of Salix at the generic and infra-generic levels is still outstanding. We have agreed to list the Egyptian species of this genus. We collected them during field trips to most Egyptian habitats; fresh and herbarium specimens were subjected to taxonomic revision based on morphological characters; scanning electron microscope (SEM) for pollen grains; isozyme analysis using esterase and peroxidase enzymes and genetic diversity using random amplified polymorphic DNA (RAPD). We recorded that both sexes of S.
I have written my most important findings in my research are as follows:
The book forty nuclear is one of the writings of the nuclear imam "God's mercy" in which he had collected ahaadeeth from several different sections and diverse, has been described by scientists as the orbit of Islam are all valid conversations.
the duty to pay attention to the Sunnah of the Prophet from the linguistic point of view because it is very rich news and constructional evidence in all sections contained the forty nuclear talks on the news sentences in (30) places divided between the news request, as stated in (13)
home and primary news in (14) home and the news denial in (3) c
... Show MoreBiosorption is an effective method to remove toxic metals from wastewaters. In this
study biosorption of lead and chromium ions from solution was studied using
Citrobacter freundii and Citrobacter kosari isolated from industrial wastewater. The
experimental results showed that optimum grwoth temperature for both bacteria is 30oC
and the optimum pH is 7 &6 for C. freundii and C. kosari respectively. While the
optimum incubation period to remove Pb and Cr for C. freundii and C. kosari is 4 days
and 3days respectively. Also the biosorption of Pb and Cr in mixed culture of bacteria
and mixed culture of Pb and Cr was investigated. Result indicate that uptake of Cr and
Pb for C.freundii, C. kosari and in mixes cultu
Venus orbit around the Sun is an ellipse inside the Earth orbit. The elements of Venus orbit and its position are affected by the gravitational force of near planets therefore the elements were determined with Julian date through ten years 2011-2020. The orbital elements used to calculate Venus distance from the Sun, the heliocentric and geocentric equatorial coordinates. From the results the orbit of Venus and its position were described and show the gravity effect of near planets on it. The results get the values and their variation through ten years for the eccentricity, semi-major axis, inclination, longitude of ascending node, argument of perihelion, mean anomaly and distance from the Sun. The variation is very small through 10 year
... Show MoreThis paper aims to study the asymptotic stability of the equilibrium points of the index 2 and index 3 Hesenberg differential algebraic equations. The problem reformulated to an equivalent explicit differential algebraic equations system, so the asymptotic stability is easily investigated. The singular points such as impasse points and singularity induced bifurcation points are identified in this kind of differential algebraic equations by using conclusion of the explicit differential algebraic equations.