Seismic response of RC frames under far-field mainshock and near-fault aftershock sequences

Seyed Amin Hosseini,Jorge Ruiz-García,Ali Massumi 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.3

Engineered structures built in seismic-prone areas are affected by aftershocks in addition to mainshocks. Although aftershocks generally are lower in magnitude than that of the mainshocks, some aftershocks may have higher intensities; thus, structures should be able to withstand the effect of strong aftershocks as well. This seismic scenario arises for far-field mainshock along with near-field aftershocks. In this study, four 2D reinforced concrete (RC) frames with different numbers of stories were designed in accordance with the current Iranian seismic design code. As a way to evaluate the seismic response of the case-study RC frames, the inter-story drift ratio (IDR) demand, the residual inter-story drift ratio (RIDR) demand, the Park-Ang damage index, and the period elongation ratio can be useful engineering demand parameters for evaluating their seismic performance under mainshock-aftershock sequences. The frame models were analyzed under a set of far-field mainshock, near-fault aftershocks seismic sequences using nonlinear dynamic time-history analysis to investigate the relationship among IDR, RIDR, Park-Ang damage index and period ratio experienced by the frames. The results indicate that the growth of IDR, RIDR, Park-Ang damage index, and period ratio in high-rise and short structures under near-fault aftershocks were significant. It is evident that engineers should consider the effects of near-fault aftershocks on damaged frames that experience far-field mainshocks as well.

Generalized coupled non-Fickian/non-Fourierian diffusion- thermoelasticity analysis subjected to shock loading using analytical method

Seyed Amin Hosseini,Mohammad Hossein Abolbashari,Seyed Mahmoud Hosseini 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.60 No.3

In this article, the generalized coupled non-Fickian diffusion-thermoelasticity analysis is carried out using an analytical method. The transient behaviors of field variables, including mass concentration, temperature and displacement are studied in a strip, which is subjected to shock loading. The governing equations are derived using generalized coupled non-Fickian diffusion-thermoelasticity theory, which is based on Lord-Shulman theory of coupled thermoelasticity. The governing equations are transferred to the frequency domain using Laplace transform technique and then the field variables are obtained in analytical forms using the presented method. The field variables are eventually determined in time domain by employing the Talbot technique. The dynamic behaviors of mass concentration, temperature and displacement are studied in details. It is concluded that the presented analytical method has a high capability for simulating the wave propagation with finite speed in mass concentration field as well as for tracking thermoelastic waves. Furthermore, the obtained results are more realistic than that of others.

Softening and Microstructure Evolution of Pure Copper Disks Processed by High Pressure Torsion

Seyed Amin Hosseini Kahnooj,Majid Vaseghi,Mahmood Sameezadeh 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.11

In this study after designing and manufacturing HPT’s anvils, copper disks with more than 99.99% purity were processedby HPT at two selected pressures for various turns. The results showed that the softening of Cu processed disks occurs veryquickly. Also, the softening range expanded from near the edge to near the center of processed disks, and this range was moreexpanded by increasing turns and pressure. The uniformity of hardness along the radius of the processed disk was obtainedat a pressure of 1.25 GPa for 2 turns. Microhardness-equivalent strain plots showed a maximum pick at the strain of 2–3 andthen it reached a steady-state at the equivalent strain of 5–6. Mean crystallite size and dislocation density were calculatedusing the Rietveld refinement method from XRD patterns. The results illustrated mean crystallite size and dislocation densitydue to recrystallization and recovery decreased by increasing pressure and turn. These results could help long-time applicationsof copper processed by SPD processes that are unusable due to long-time softening.

Enhancing removal and recovery of magnesium from aqueous solutions by using modified zeolite and bentonite and process optimization

Seyed Saeid Hosseini,Mohammad Amin Alaei Shahmirzadi,Nicolas Raymond Tan 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.12

Natural and modified zeolite and bentonite are investigated and characterized for extraction of magnesium from aqueous solutions. Magnesium removals as high as 85.21% and 81.73% were achieved by calcined bentonite and microwave radiated zeolite, respectively. The effects of various operational parameters were studied and optimized using selected isotherms. Maximum Mg (II) adsorption capacities of 26.24 and 35.67mg·g−1 were obtained on pristine and calcined bentonites, respectively. Thermodynamic studies suggest that magnesium adsorption on natural bentonite is spontaneous and endothermic (9.13 kj·mol−1). Also, desorption study of natural bentonite demonstrates that HNO3 is more effective by offering 89.11% desorption than other desorptive counterparts.

A Novel Cell Disruption Approach: Effectiveness of Laser-induced Cell Lysis of Pichia pastoris in the Continuous System

Maryam Gazor,Seyed Siamak Ashraf Talesh,Alireza kavianpour,Maryam Khatami,Amin Javidanbardan,Seyed Nezamedin Hosseini 한국생물공학회 2018 Biotechnology and Bioprocess Engineering Vol.23 No.1

In biotechnological processes, often cell disruption has been an inevitable step as current host cells express most of the desired products intracellularly. Thus, an appropriate cell disruption technique must be selected considering different factors including the target product, process scale, and cell wall structure. In the current study, as a novel method, the efficacy of cell disruption via laser was tested qualitatively and quantitatively in batch and continuous systems, respectively. Laser-induced cell lysis can be a clean, rapid and convenient alternative to the other conventional disruption techniques. Our investigations in the continuous system with a flow rate of 800 μL/sec proved efficient (~ 90%) Pichia pastoris cell disruption at the wavenumber 1,064 nm with the energy input of 284 mW after four complete rounds of circulation. The main mechanism of cell disruption is assumed to be thermolysis via instant heat increase in the laser-treated spot. The results of the current study showed that continuous laser system could be applied in laboratory and industry scale for cell disruption.

Burden of Breast Cancer in Iranian Women is Increasing

Sharifian, Abdolhamid,Pourhoseingholi, Mohamad Amin,Emadedin, Majid,Nejad, Mohammad Rostami,Ashtari, Sara,Hajizadeh, Nastaran,Firouzei, Seyed Alireza,Hosseini, Seyed Jalil Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.12

Background: Breast cancer (BC) is the leading cause of oncological death for women, in both developed and developing countries. In Iran, breast cancer ranks first among cancers diagnosed in women. The aim of this study was to present the burden of this cancer including incidence, mortality and years life lost (YLL) due to breast cancer in Iranian women. Materials and Methods: National incidence data from the Iranian annual National Cancer Registration reports from 2003 to 2009 and national death statistics reported by the Ministry of Health and Medical Education from 1995 to 2010, stratified by age group, were included in this analysis. Also calculated YLLs provided by the Institute for Health Metrics and Evaluation (IHME) for the years 1990, 1995, 2000, 2005 and 2010 were employed to express the years lost due to BC for Iranian women. Results: The general mortality rate of breast cancer increased during these years from 0.96 to 4.33 per 100,000 and incidence increased from 16.0 to 28.3 per 100,000 for the years under study. YLLs calculated by IHME showed both increasing and decreasing patterns, with a tendency for stabilization. Conclusions: The burden of breast cancer for Iranian women is still increasing. Thus, health education programs to inform women regarding the signs and risk factors, and national screening to facilitate early diagnosis are needed for the female community in Iran.