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M. Ghassemieh,Sokhtesaraei M. Hassani,S.R. Mirghaderi 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.2
The strength and deformation capacity of structural elements are infl uenced by their cumulative damages received through load cycles. Loading protocols would provide the estimation of the structural components’ capacities and a proper simulation of the seismic reality, which are used to assess the performance of connections. Given the widespread application of I-beam to box-column moment connections, the seismic performance of moment connections in the box-columns should be thoroughly investigated. However, most regulation details for the qualifi cation of moment connections are presented for the H-shaped columns. Accordingly, in this study, 12 prequalifi ed types of RBS and WUF-W moment connections in the boxcolumns are selected and analyzed under diff erent cyclic loading scenarios. Therefore, the seismic behavior of such moment connections is studied for the drift qualifying criteria and collapse threshold when they are subjected to the SAC and ATC- 24 loading protocols. Besides, energy dissipation, demand, loading protocols’ impact, and their infl uences are examined.
M. Hassani,M.M. Monfared,A. Salarvand 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.86 No.4
In the present paper, multiple interface cracks between a functionally graded orthotropic coating and an orthotropic half-plane substrate under concentrated loading are considered by means of the distribution dislocation technique (DDT). With the use of integration of Fourier transform the problem is reduced to a system of Cauchy-type singular integral equations which are solved numerically to compute the dislocation density on the surfaces of the cracks. The distribution dislocation is a powerful method to calculate accurate solutions to plane crack problems, especially this method is very good to find SIFs for multiple unequal cracks located at the interface. Hence this technique allows considering any number of interface cracks. The primary objective of this paper is to investigate the effects of the interaction of multiple interface cracks, load location, material orthotropy, nonhomogeneity parameters and geometry parameters on the modes I and II SIFs. Numerical results show that modes I/II SIFs decrease with increasing the nonhomogeneity parameter and the highest magnitude of SIF occurs where distances between the load location and crack tips are minimal.
WUF-W Moment Connection in Steel Box-Column Subjected to the New Cyclic Loading Protocol
M. Hassani Sokhtesaraei,M. Ghassemieh,S.R. Mirghaderi 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.4
Loading protocols simulate local earthquakes are usually used to evaluate structural components’ strength and deformation capacities. First, the present research proposes a loading protocol that accurately simulates the local seismic demand based on far-fi eld conditions, while being also consistent with the region’s structural design and construction conditions. The proposed loading protocol can be applied to the steel structure’s bending components, particularly the steel moment connections in general and experimental terms. Moreover, the proposed loading protocol presents the guidelines for evaluating the moment connections’ performance at the target, qualifying, and collapse control levels. Similar specimens of welded unreinforced fl ange-welded web (WUF-W) steel moment connections in box-columns were subjected to the proposed and SAC loading protocols in the laboratory; and the results were analysed. Based on the experimental and fi nite element studies performed in this research and matching and controlling the proposed loading protocol’s presented conditions and regulations, the damage parameters and the seismic demand resulting from both loading protocols were evaluated and compared. The experimental and fi nite element of the WUF-W connections have well satisfi ed the target value level; and the qualifying condition of the proposed and SAC loading protocols and the control conditions of the collapse threshold provided in the proposed loading protocol was well satisfi ed the experimental specimen.
Saud M. Almotairy,A. Fadavi Boostani,M. Hassani,D. Wei,Z. Y. Jiang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.5
This study discusses the superior effect of thixoforming process on enhancing the tensile properties of aluminium matrixcomposite produced using flake metallurgy route. The flake metallurgy process was utilised to manufacture aluminiummatrix composites followed by thixoforming process. Microstructural investigations carried out using transmission electronmicroscope have shown the synergic effect of thixoforming process on rendering uniform distribution of SiC nanoparticlesassociated with lower porosity content. X-ray diffraction characterisations have revealed the promising effect of uniformdispersion of SiC nanoparticles on restricting the grain growth of aluminium matrix within nanoscale regime (90 nm) evenat high semi-solid thixoforming temperatures (575 °C). The achieved results of tensile tests have shown a profound effect offlake metallurgy of aluminium powder through dual speed ball milling. These results are higher than those achieved by lowspeed and high speed even with higher SiC content. This was attributed to the uniform confinement of SiC nanoparticleswithin the samples produced using flake-assisted forming process compared to the ones manufactured using ball millingassistedprocesses.
Moslemipur, F.,Torbatinejad, N.M.,Khazali, H.,Hassani, S.,Ghoorchi, T. Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.6
Insulin has crucial roles in energy metabolism in all mammals but has been less studied in ruminants. An experiment was conducted to investigate the effects of hypoinsulinemia induction on appetite, performance, carcass composition and blood metabolite levels in sheep. Treatments were intravenous injection of four doses of streptozotocin; 0, 25, 50 and 75 mg/kg BW named C, L, M and H, respectively. Twenty male lambs were divided into four treatment groups. Animals in group H could not continue the experiment because of abnormalities. The duration of the experiment was eight consecutive weeks, and injection was performed at the end of week 3. Feed and water intakes were measured weekly and weight changes of animals were recorded and used for calculation of other growth parameters. Blood samples were collected weekly via venipuncture at fasting and 2.5 h post-prandial and analyzed for hormones and blood metabolites. Results showed a marked hypoinsulinemia in group M with significant decrease in fasted and postprandial insulin concentrations and also fasted leptin concentrations vs. the control group C (p<0.05). Group M showed significant increases in blood glucose, triglycerides, cholesterol, total protein, blood urea nitrogen and ketone body levels vs. group C (p<0.05). After injection, animals in group M showed diabetic hyperphagia and enhanced water intake as compared to group C (p<0.05) but, despite increased feed intake, they did not gain more weight than controls (p<0.05), and consequently, their feed conversion ratio was greater. Protein and fat contents of meat and liver were not significantly different among groups (p>0.05). In conclusion, the results suggested a regulatory role of insulin in energy metabolism of ruminants by exerting two opposing effects; central catabolic and peripheral anabolic.
A. A. El Hassani,Z. El Adnani,A. T. Benjelloun,M. Sfaira,M. Benzakour,M. Mcharfi,B. Hammouti,K. M. Emran 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.11
Quantum chemical study, based on DFT methods at B3LYP/6-31G (d, p) level of theory, of four tetrazole compounds,denoted Ph-T, Me-Ph-T, MeO-Ph-T, Cl-Ph-T and reported as corrosion inhibitors in acidic medium, has been investigatedin an attempt to find relationships between their molecular electronic properties and their corresponding experimental corrosioninhibition efficiencies. The global reactivity descriptors, such as the frontier molecular orbital energies (EHOMO andELUMO), energy gap ΔE, electronegativity χ, absolute hardness η and softens σ, fraction of electrons transferred ΔN as wellas local selectivity parameters such as Natural Atomic Populations and Fukui indices were also calculated and discussed. The calculations were undertaken in both gaseous and aqueous states for a better approach of the experimental conditions. The results showed that Cl-Ph-T presented the lowest ELUMO and the highest χ indicating its high electron acceptor ability,which can explain its good corrosion inhibition efficiency when compared to the three-other studied tetrazole derivatives.