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Development of a new method for joint damping identification in a bolted lap joint
M. Sanati,Y. Terashima,E. Shamoto,S. S. Park 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.5
Mechanical joints have considerable effects on dynamic behaviour of machine tools; thus, joint damping identification is important in studying the dynamics of mechanical structures. Due to the difficulties in analysis of microslip friction, the experimental prediction of microslip joint dynamics is of great importance. In this study, a new experimental approach is proposed to determine the damping of bolted lap joints. Because of the complex nature of the mechanical joints, the lap joint is isolated through the addition of a mechanical resonator, which consists of a lumped mass and spring, to the bolted structure. The frequency response function (FRF) of this system is used for joint damping identification. This approach is used for bolted structures under both translational and torsional excitations and overcomes difficulties associated with slip boundaries identification in the joint interface. The method is verified by comparing the obtained results with those of the hysteresis loop approach.
Ni(OH)2 and NiO Nanostructures: Synthesis, Characterization and Electrochemical Performance
Lotf Ali Saghatforoush,Mohammad Hasanzadeh,Soheila Sanati,Robabeh Mehdizadeh 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.8
Hydrothermal route have been used in different conditions for preparation of Ni(OH)2 nanostructures. The NiO nanoparticles were obtained by calcining the Ni(OH)2 precursor at 450 °C for 2 h. The effect of sodium dodecyl sulfonate (SDS) as surfactant on the morphology and size of Ni(OH)2 nanoparticles were discussed in detail. X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy were used to characterize the products. The growth mechanism of the as-synthesized nanostructures was also discussed in detail based on the experimental results. Coming up, the NiO nanoparticle modified carbon paste electrode was applied to the determination of captopril in aqueous solution.
Saghatforoush, Lotf Ali,Hasanzadeh, Mohammad,Sanati, Soheila,Mehdizadeh, Robabeh Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.8
Hydrothermal route have been used in different conditions for preparation of $Ni(OH)_2$ nanostructures. The NiO nanoparticles were obtained by calcining the $Ni(OH)_2$ precursor at $450^{\circ}C$ for 2 h. The effect of sodium dodecyl sulfonate (SDS) as surfactant on the morphology and size of $Ni(OH)_2$ nanoparticles were discussed in detail. X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy were used to characterize the products. The growth mechanism of the as-synthesized nanostructures was also discussed in detail based on the experimental results. Coming up, the NiO nanoparticle modified carbon paste electrode was applied to the determination of captopril in aqueous solution.
Strengthening of concrete structures with buckling braces and buckling restrained braces
Mazloom, Moosa,Pourhaji, Pardis,Farash, Abbas Moosa,Sanati, Amir Hossein Techno-Press 2018 Structural monitoring and maintenance Vol.5 No.3
The purpose of this article is to strengthen concrete structures using buckling and non-buckling braces. Connection plates are modeled in three shapes including the effect of 1.5t hinge zone length, 2t one and without the zone (1.5t-CP, 2t-CP and WCP). According to the verification performed with ABAQUS software, the connection plates which are superior in ductility and strengthening are found. The results show adding steel braces in concrete moment frames increase the strength and stiffness of the structures up to about 12 and 3 times, respectively. The frame strength increased about 21 and 25 percent with considering the effect of 2t hinge length in connection plates compared to 1.5t-CPs and WCPs. Also the ductility of retrofitted frames with 2t-CP improved 2.06 times more than WCP ones. Thus, 2t-CP sample is the best choice for connecting steel braces to concrete moment frames for retrofitting them. Afterwards, optimum conditions for elemental coating in braces with no buckling are assessed. The length of concrete coatings could be reduced about 30 percent, and buckling did not occur. Therefore, the weight of restraining coating decreased, and its performance improved. It is worth noting that BRBs could be constructed with only steel materials, which have outer steel tubes too. In fact, only the square cross sections of the tube profiles are appropriate for removing the filler concrete, and the rectangular ones are prone to buckle around their weak axis.
Moosavi, Mohammad Amin,Yazdanparast, Razieh,Sanati, Mohammad Hasan Korean Society for Biochemistry and Molecular Biol 2005 Journal of biochemistry and molecular biology Vol.38 No.4
3-hydrogenwadaphnin (3-HK) is a new daphnane-type diterpene ester isolated from Dendrostellera lessertii with strong anti-tumoral activity in animal models and in cultures. Here, prolonged effects of this new agent on proliferation and viability of several different cancerous cell lines were evaluated. Using [$^3H$]thymidine incorporation, it was found that the drug inhibited cell proliferation and induced G1/S cell cycle arrest in leukemic cells 24 h after a single dose treatment. The cell viability of Jurkat cells was also decreased by almost 10%, 31% and 40% after a single dose treatment (7.5 nM) at 24, 48 and 72 h, respectively. The drug-treated cells were stained with acridine orange/ethidium bromide to document the chromatin condensation and DNA fragmentation. These observations were further confirmed by detection of DNA laddering pattern in the agarose gel electrophoresis of the extracted DNA from the treated cells. Treatment of K562 cells with the drug at 7.5, 15 and 30 nM caused apoptosis in 25%, 45% and 65% of the cells, respectively. Exogenous addition of $25-50\;{\mu}M$ guanosine and/or deoxyguanosine to the cell culture of the drug-treated cells restored DNA synthesis, released cell arrest at G1/S checkpoint and decreased the apoptotic cell death caused by the drug. These observations were not made using adenosine. However, the drug effects on K562 cells were potentiated by hypoxanthine. Based on these observations, perturbation of GTP metabolism is considered as one of the main reasons for apoptotic cell death by 3-HK.
A pore-scale model for microfibrous ammonia cracking microreactors via lattice Boltzmann method
Gholam Reza Molaeimanesh,Mohammad Hosein Sanati Davarani 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.4
Microfibrous microreactors with high reactive surface-to-volume ratio are good choices for ammonia cracking, which is one of the main strategies for CO-free hydrogen production. In the current study, a numerical model based on the lattice Boltzmann method (LBM) is presented to investigate ammonia cracking microreactors with coupled physiochemical thermal processes at the pore scale. Several sets of transport phenomena such as fluid flow, species transport, heat transfer and chemical reaction are taken into account. Moreover, to model the species transport in the ammonia cracking microreactor an active approach is applied for the first time. The model is validated and then employed to simulate the reactive transport in five different microreactors with dissimilar structural parameters. Comparison of the results shows that the fibers orientation is an effective geometric parameter that can greatly influence the hydrogen production efficiency.