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.
The political system in Indonesia, since gaining independence from the Dutch colonialism on the seventeenth of August 1945, has gone through long stages. The Indonesian constitution stipulated that the country is based on a democracy. In 1956 the first free elections were held in Indonesia, and President Sukarno announced the adoption of the directed democratic system Then, during the era of President Suharto, the state entered a phase called democracy based on the Five Pancasila principles, which is a false democracy because it served the interests of Suharto, who in his long reign had political and economic corruption leading up to 1998, when the Indonesian people revolted, and the government of Soeharto was overthrown
... Show MoreIn this study, the effect of the combination of micro steel fibers and additives (calcium hydroxide and sodium carbonate) on the size of cracks formation and healing them were investigated. This study aims to apply the use of self-healing phenomenon to repair cracks and to enhance the service life of the concrete structures. Micro steel fibers straight type were used in this research with 0.2% and 0.4% by volume of concrete. A weight of 20 and 30 kg/m3 of Ca(OH)2 and 2 and 3 kg/m3 of Na2CO3 were used as a partial cement replacement. The results confirm that the concrete cracks were significantly self-healed up to 30 days re-curing. Cracks width up to 0.2 mm were comp
... Show Moreان من اهم القضايا التي تثيرها المعرفة البشرية في تجلياتها، وتعبيراتها المفاهيمية، تكمن في مدى تأصلها وانتمائها الى البنى والتشكيلات الموضوعية (في مستوياتها التاريخية) التي تسعى لتفسيرها وادراكها ومضاهاتها. فالينبوع الذي يغرف منه الفكر مادته هو الكيان الاجتماعي المتموضع خارج الوعي والايدولوجيا.
ان قدرة الوعي على ادراك الواقع الموضوعي بخصائصه العامة يشكل الشرط الضروري لاكتساب الوعي ل
... Show MoreAlO-doped ZnO nanocrystalline thin films from with nano crystallite size in the range (19-15 nm) were fabricated by pulsed laser deposition technique. The reduction of crystallite size by increasing of doping ratio shift the bandgap to IR region the optical band gap decreases in a consistent manner, from 3.21to 2.1 eV by increasing AlO doping ratio from 0 to 7wt% but then returns to grow up to 3.21 eV by a further increase the doping ratio. The bandgap increment obtained for 9% AlO dopant concentration can be clarified in terms of the Burstein–Moss effect whereas the aluminum donor atom increased the carrier's concentration which in turn shifts the Fermi level and widened the bandgap (blue-shift). The engineering of the bandgap by low
... Show MoreThe influence of sintering and annealing temperatures on the structural, surface morphology, and optical properties of Ag2Cu2O4 thin films which deposited on glass substrates by pulsed laser deposition method have been studied. Ag2Cu2O4 powders have polycrystalline structure, and the Ag2Cu2O4 phase was appear as low intensity peak at 35.57o which correspond the reflection from (110) plane. Scan electron microscopy images of Ag2Cu2O4 powder has been showed agglomerate of oxide particles with platelets shape. The structure of thin films has been improved with annealing temperature. Atomic Force micrographs of Ag2Cu2O4 films showed uniform, homogenous films and the shape of grains was almost spherical and larger grain size of 97.85 nm has o
... Show MoreThe study aimed to measure the phsycological tolerance and self-efficacy among the students of Baghdad university and knon the significant differences in psychological tolerance and self-efficacy according to the variables (Gender-Specialization)and the interaction between themas well as the study aimed to identify the strength and direction of the relationship between psychological tolerance and self-efficacy of the study sampleincluded asample of the current study(370) students from grades four ,the researcher used the measure of psychological tolerance and self-efficacy prepared by the researcher ,and the results showed that college students Generally have adegree of psychological tolerance and that there are statistically sig
... Show MoreThe current research aims to identify pictorial coding and its relationship to the aesthetic taste of art education students. The research community consisted of (10) plastic artworks, and (3) artworks were selected as a sample for analysis and decoding. With the aim of the research, the research tool was prepared as it consisted of an analysis form, and the researcher used statistical methods: Equation (Cooper) to find the percentage of agreement between the arbitrators and the equation (Scott) to calculate the validity of the tool, and the correlation coefficient (Pearson) to extract stability in the method of segmentation half. Shape formations and achieve encryption of the plastic image through decoding symbols, meanings, and the sig
... Show MoreThis study was carried out in Plant Tissue Culture Labs, College of Agricultural Engineering Sciences, University of Baghdad from November 2018 to June 2019. Fresh stem cuttings, 5 cm long were selected from 6-month old C-35 Citrange rootstock. Five concentrations of BA (0, 1, 1.5, 2 and 2.5 mg.L-1) were studied and addition of meta-Topolin (mT) at four concentrations (0, 1, 5 and 10 mg.L-1) was also studied to find out its effect individually on shoot number and shoot length in multiplication stage. Rooting media supplemented with four concentrations of IBA (0, 1, 2 and 3 mg.L-1) was also studied to find out its effect on rooting percentage, root number and root length. Results showed that BA as concentration of 2.5mg.L-1 significantly gav
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