Numerical Modeling of Train-induced Vibration of Nearby Multi-story Building: A Case Study

Saeed Hesami,Saeed Ahmadi,Abbasali Taghavi Ghalesari 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.5

In recent years, ground vibration has become a popular research topic due to the growing construction close to vibration sources and the attentiveness of people about living conditions. Thus, vibrations caused by the passage of the train near buildings play an important role. In prediction of train-induced vibrations, many experimental and theoretical methods have been proposed. In order to study the vibration near the railway at Qaemshahr, a 2D finite element analysis employed for modeling of the train movement and its effect on the adjacent building. The validation of the numerical model was done by the high-speed train running measurements. The results show that the vibration level decreases by increasing the track centerline to building distance and decreasing train speed. The frequency of vibration up to 12 Hz was present in the incident wave field and the dominating part of the frequency content was between 2.5 and 5.5 Hz. The building foundation bending moment variations caused by train-induced vibrations was negligible. The track centerline to building edge distance of 18 m was seemed to be an acceptable value to reduce the annoyance and environmental effects caused by train-induced vibrations.

Regularizing structural configurations by using meta-heuristic algorithms

Massah, Saeed Reza,Ahmadi, Habibullah Techno-Press 2017 Geomechanics & engineering Vol.12 No.2

This paper focuses on the regularization of structural configurations by employing meta-heuristic optimization algorithms such as Particle Swarm Optimization (PSO) and Biogeography-Based Optimization (BBO). The regularization of structural configuration means obtaining a structure whose members have equal or almost equal lengths, or whose member's lengths are based on a specific pattern; which in this case, by changing the length of these elements and reducing the number of different profiles of needed members, the construction of the considered structure can be made easier. In this article, two different objective functions have been used to minimize the difference between member lengths with a specific pattern. It is found that by using a small number of iterations in these optimization methods, a structure made of equal-length members can be obtained.

Inhibition of quorum sensing in Pseudomonas aeruginosa by two herbal essential oils from Apiaceae family

Ehsan Sepahi,Saeed Tarighi,Farajollah Shahriari Ahmadi,Abdolreza Bagheri 한국미생물학회 2015 The journal of microbiology Vol.53 No.2

Ferula (Ferula asafoetida L.) and Dorema (Dorema aucheri Bioss.) both from Apiaceae family were tested for their antiquorum sensing (QS) activity against Pseudomonas aeruginosa. Both essential oils exhibited anti-QS activity at 25 μg/ml of concenteration. At this concenteration Ferula fully abolished and Dorema reduced the violacein production by C. violaceum. Pyocyanin, pyoverdine, elastase and biofilm production were decreased in Ferula oil treatments. Dorema oil reduced pyoverdine and elastase production, while pyocyanin and biofilm production were not affacted. Expresion analysis of QS-dependent genes confirmed our phenotypic data. Our data introduced native Dorema and Ferula plants as novel QS and virulence inhibitors.

Improved Executive Functions and Reduced Craving in Youths with Methamphetamine Addiction: Evidence from Combined Transcranial Direct Current Stimulation with Mindfulness Treatment

Jaber Alizadehgoradel,Saeed Imani,Vahid Nejati,Marie-Anne Vanderhasselt,Behnam Molaei,Mohammad Ali Salehinejad,Shirin Ahmadi,Mina Taherifard 대한정신약물학회 2021 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.19 No.4

Objective: Transcranial direct current stimulation (tDCS) and mindfulness practices have been proposed as a potential approach to improve executive functions (EFs) and reduce craving in persons with substance use disorders. Based on the neural mechanisms of action of each of these interventions, the combination of both non-pharmacological interventions might have additive effects. In the current study, the effects of tDCS combined with mindfulness-based substance abuse treatment (MBSAT) to improve EFs and reduce craving were investigated in early abstinent methamphetamine abuse. Methods: Eighty (youths aged between 18 and 21) early-abstinent methamphetamine users were randomly assigned to the research groups (tDCS group [n = 20], mindfulness group [n = 20], combined mindfulness-tDCS group [n = 20], and sham group [n = 20]). Active tDCS (1.5 mA,20 min, 12 sessions) or sham tDCS was appliedover the left dorsolateral prefrontal cortex and the MBSAT protocol was used over twelve 50-min sessions. Results: Both in the post-test phase (immediately after the intervention) and follow-up phase (one month after the intervention), performance in most EFs tasks significantly improved in the combination group which received real tDCS + MBSAT, as compared to baseline values and sham stimulation group. Similarly, a significant reduction in craving was observed after intervention inall treatment groups, but not the sham stimulation group. Interestingly, the increase in EFs and the reduction in craving post versus pre tDCS + MBSAT intervention were correlated. Conclusion: Findings from the current study provide initial support for the clinical effectiveness of combination tDCS + MBSAT, possibly influencing cognitive/affective processes.

Analysis of sulfur removal in gasoil hydrodesulfurization process by application of response surface methodology

Sorood Zahedi Abghari,Saeed Shok,Behnam Baloochi,Mehdi Ahmadi Marvast,Shahram Ghanizadeh,Afshin Behroozi 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.1

To investigate the efficiency of a Co-Mo catalyst in HDS process, a set of experiments were designed and carried out based on central composite design (CCD) methodology in an HDS pilot plant. The designed variables included temperature, LHSV and pressure. However, the hydrogen over fresh feed ratio remained constant. The ranges of these variables were, respectively, equal to 335-361℃ , 1.06-1.8 1/hr and 46.8-53.2 bar. The outcomes of experiments were employed to determine the coefficients of statistical models. For the clarification of the accuracy of the model,several statistical tests like ANOVA (Analysis of Variance), Lack-of-Fit test and residual squares were carried out. To optimize the operating conditions to achieve maximum sulfur removal, an optimization algorithm was employed. The outcomes revealed that the minimum sulfur content, which is 23.65 ppm in the final product, is attained at 355℃, 1.2 1/hr and 49.2 bar.

Synthesis and employment of PEGDA for fabrication of superhydrophilic PVDF/PEGDA electrospun nanofibrous membranes by in-situ visible photopolymerization

Hamid Reza Ashjari,Arsalan Ahmadi,Mir Saeed Seyed Dorraji 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.1

A methodology for the synthesis of light curable poly(ethylene glycol) diacrylate (PEGDA) is described. PEGDA synthesis was confirmed using 1H NMR, 13C NMR, and infrared spectroscopy. The resin was used for fabrication of the superhydrophilic PVDF/PEGDA nanofibrous membrane in a single processing step. For the in-situ photo cross-linking reaction during electrospinning process, the electrospinning apparatus was equipped with a visible light source. Degree of conversion of double bonds during electrospinning process and interaction between the two polymers were investigated by FT-IR spectrum. To determine the potential applications of the as-prepared the membranes in wastewater treatment, parameters such as morphology, hydrophilicity and water resistance were investigated by scanning electron microscopy (SEM), tensile strength, static water contact angle (WCA) and Fourier transform infrared spectroscopy (FT-IR). The results showed that PVDF/PEGDA (40/60) nanofibrous membrane is superhydrophilic and insoluble in water.

Computational fluid dynamics studies of dry and wet pressure drops in structured packings

Seyyed Hossein Hosseini,Saeed Shojaee,Goodarz Ahmadi,Mortaza Zivdar 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.4

Computational fluid dynamics was used to study the hydrodynamic of structured packings. The results showed that the k–v was a suitable turbulence model for analyzing the flows in structured packings. A simple method was proposed for evaluating the liquid holdup based on the Iliuta and Larachi (2001)model [25], the calculated liquid film thickness in 2D framework, and the empirical correlation of Brito et al. (1994) [26]. The presented method can be used for estimating the wet pressure drop in 3D structured packings for loading region with good accuracy as well as computational economy. The process of liquid film formation was also discussed.

Theoretical Study of Thiazole Adsorption on the (6,0) zigzag Single-Walled Boron Nitride Nanotube

Ali Varasteh Moradi,Ali Ahmadi Peyghan,Saeede Hashemian,Mohammad T. Baei 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

The interaction of thiazole drug with (6,0) zigzag single-walled boron nitride nanotube of finite length in gas and solvent phases was studied by means of density functional theory (DFT) calculations. In both phases, the binding energy is negative and presenting characterizes an exothermic process. Also, the binding energy in solvent phase is more than that the gas phase. Binding energy corresponding to adsorption of thiazole on the BNNT model in the gas and solvent phases was calculated to be −0.34 and −0.56 eV, and about 0.04 and 0.06 electrons is transferred from the thiazole to the nanotube in the phases. The significantly changes in binding energies and energy gap values by the thiazole adsorption, shows the high sensitivity of the electronic properties of BNNT towards the adsorption of the thiazole molecule. Frontier molecular orbital theory (FMO) and structural analyses show that the low energy level of LUMO, electron density, and length of the surrounding bonds of adsorbing atoms help to the thiazole adsorption on the nanotube. Decrease in global hardness, energy gap and ionization potential is due to the adsorption of the thiazole, and consequently, in the both phases, stability of the thiazole-attached (6,0) BNNT model is decreased and its reactivity increased. Presence of polar solvent increases the electron donor of the thiazole and the electrophilicity of the complex. This study may provide new insight to the development of functionalized boron nitride nanotubes as drug delivery systems for virtual applications.

Prediction of concrete strength in presence of furnace slag and fly ash using Hybrid ANN-GA (Artificial Neural Network-Genetic Algorithm)

Mahdi Shariati,Mohammad Saeed Mafipour,Peyman Mehrabi,Masoud Ahmadi,Karzan Wakil,Nguyen Thoi Trung,Ali Toghroli 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.2

Mineral admixtures have been widely used to produce concrete. Pozzolans have been utilized as partially replacement for Portland cement or blended cement in concrete based on the materials' properties and the concrete's desired effects. Several environmental problems associated with producing cement have led to partial replacement of cement with other pozzolans. Furnace slag and fly ash are two of the pozzolans which can be appropriately used as partial replacements for cement in concrete. However, replacing cement with these materials results in significant changes in the mechanical properties of concrete, more specifically, compressive strength. This paper aims to intelligently predict the compressive strength of concretes incorporating furnace slag and fly ash as partial replacements for cement. For this purpose, a database containing 1030 data sets with nine inputs (concrete mix design and age of concrete) and one output (the compressive strength) was collected. Instead of absolute values of inputs, their proportions were used. A hybrid artificial neural network-genetic algorithm (ANN-GA) was employed as a novel approach to conducting the study. The performance of the ANN-GA model is evaluated by another artificial neural network (ANN), which was developed and tuned via a conventional backpropagation (BP) algorithm. Results showed that not only an ANN-GA model can be developed and appropriately used for the compressive strength prediction of concrete but also it can lead to superior results in comparison with an ANN-BP model.

Theoretical Study of Thiazole Adsorption on the (6,0) zigzag Single-Walled Boron Nitride Nanotube

Moradi, Ali Varasteh,Peyghan, Ali Ahmadi,Hashemian, Saeede,Baei, Mohammad T. Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

The interaction of thiazole drug with (6,0) zigzag single-walled boron nitride nanotube of finite length in gas and solvent phases was studied by means of density functional theory (DFT) calculations. In both phases, the binding energy is negative and presenting characterizes an exothermic process. Also, the binding energy in solvent phase is more than that the gas phase. Binding energy corresponding to adsorption of thiazole on the BNNT model in the gas and solvent phases was calculated to be -0.34 and -0.56 eV, and about 0.04 and 0.06 electrons is transferred from the thiazole to the nanotube in the phases. The significantly changes in binding energies and energy gap values by the thiazole adsorption, shows the high sensitivity of the electronic properties of BNNT towards the adsorption of the thiazole molecule. Frontier molecular orbital theory (FMO) and structural analyses show that the low energy level of LUMO, electron density, and length of the surrounding bonds of adsorbing atoms help to the thiazole adsorption on the nanotube. Decrease in global hardness, energy gap and ionization potential is due to the adsorption of the thiazole, and consequently, in the both phases, stability of the thiazole-attached (6,0) BNNT model is decreased and its reactivity increased. Presence of polar solvent increases the electron donor of the thiazole and the electrophilicity of the complex. This study may provide new insight to the development of functionalized boron nitride nanotubes as drug delivery systems for virtual applications.