Numerical and Experimental Investigations of Trajectory Eff ects into Temperature Distribution and Distortion in the Slot Welding of Steel S235JR

Ebrahim Nateghi,Abdolhamid Gorji Volukola 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.3

One of the signifi cant factors that impresses on welded parts’ performance is welding trajectory. Slotted samples with loop and parallel trajectories welded by two steel plates by S235JR and GMAW process. Temperature distributions were registered by the four K type thermocouples. Heat aff ected zone dimensions were measured on polished and etched cross-sections of each sample. Induced distortions by dial indicators were gauged along welding process and cooling. To evaluate temperature fi eld and distortion in the welding process, three-dimensional FE models were performed. There was good agreement between the FE model predictions and experimental measurements. The most temperatures, distortions and induced longitudinal and transverse residual stresses by welding in the loop trajectory were more than the parallel.

Determination of plastic concrete behavior at different strain rates to determine Cowper-Symonds constant for numerical modeling

Reza Nateghi,Kamran Goshtasbi,Hamid Reza Nejati 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.26 No.3

Strain rate investigations are needed to calibrate strain-rate-dependent material models and numerical codes. An appropriate material model, which considers the rate effects, need to be used for proper numerical modeling. The plastic concrete cut-off wall is a special underground structure that acts as a barrier to stop or reduce the groundwater flow. These structures might be subjected to different dynamic loads, especially earthquake. Deformability of a structure subjected to dynamic loads is a principal issue which need to be undertaken during the design phase of these structures. The characterization of plastic concrete behavior under different strain rates is essential for proper designing of cut-off walls subjected to dynamic loads. The Cowper-Symonds model, as one of the most commonly applied material models, complies well with the behavior of a plastic concretes in low to moderate strain rates and will be useful in explicit dynamics simulations. This paper aims to present the results of an experimental study on mechanical responses of one of the most useful types of plastic concrete and Cowper- Symonds constant determination procedures in a wide range of strain rate from 0.0005 to 107 (1/s). For this purpose, SHPB, uniaxial, and triaxial compression tests were done on plastic concrete samples. Based on the results of quasi-static and dynamic tests, the dynamic increase factors (DIF) of this material in different strain rates and stress state conditions were determined for calibration of the Cowper - Symonds material models.

In Vitro Assessment of Antioxidant and Antibacterial Activities of Six Edible Plants from Iran

Reza Tabaraki,Ashraf Nateghi,Salman Ahmady-Asbchin 사단법인약침학회 2013 Journal of Acupuncture & Meridian Studies Vol.6 No.3

The antioxidant and antibacterial activities of six edible plants were evaluated. The active constituents of the edible plants were extracted using boiling water or 80% methanol. Results demonstrated that extraction of antioxidants by boiling water was more efficient. Lycium depressum and Berula angustifolia had the highest antioxidant activities and, therefore, could be rich sources of natural antioxidants. The antibacterial activities of the extracts were tested against Staphylococcus aureus, Escherichia coli, Entrococcus faecalis and Proteus mirabilis. Further research is needed to isolate, characterize, and identify the bioactive compounds present in these plants.

Effect of Structural Uncertainty on Seismic Response of Steel Moment-resisting Frames Equipped with Tuned Mass Dampers

Karim Tarbali,Fariborz Nateghi-A 한국강구조학회 2014 International Journal of Steel Structures Vol.14 No.2

Tuned mass dampers (TMDs) can be used to absorb the input energy of the applied loads, and reduce the response of buildingframes. However, inherited uncertainties in structural characteristics of building frames can significantly affect their responseand counteract the effectiveness of vibration absorbing devices such as TMDs. In this study, by calculating cumulative damageindices for stories of the structure, failure probability of two steel moment-resisting frames equipped with TMDs has beenstudied in presence of uncertainty in characteristics of the structure. Cumulative inelastic deformation of structural elements ineach story has been used to calculate the damage representative of that story, based on weighted average approach. Even thoughthe cumulative response of the deterministic model of the structures is reduced by installing TMDs, the results of the numericalsimulations on the probabilistic response of the sample structures indicate that for the records that cause excessive damage inthe lower stories of the structures, the effect of TMDs on failure probability of the structure can be detrimental.

Seismic behavior of three dimensional concrete rectangular containers including sloshing effects

Mirzabozorg, H.,Hariri-Ardebili, M.A.,Nateghi A., R. Techno-Press 2012 Coupled systems mechanics Vol.1 No.1

In the present paper, the three-dimensional model of a typical rectangular concrete tank is excited using an artificial and a natural three components earthquake ground motion and the staggered displacement method is utilized for solving the coupled problem of the tank-contained liquid system in time domain. In the proposed method, surface sloshing of the liquid is taken into account in addition to the impulsive term and the appropriate damping values are applied on both of them. The resulted responses are compared with those obtained from the ABAQUS finite element software. It is found that the convective term affects responses extensively and must be considered in seismic design/safety assessment of storage tanks. In addition, the utilized method for solving the coupled problem is stable during the conducted general dynamic analyses and is able to capture the expected phenomena.

Association of Poor Prognosis Subtypes of Breast Cancer with Estrogen Receptor Alpha Methylation in Iranian Women

Izadi, Pantea,Noruzinia, Mehrdad,Fereidooni, Foruzandeh,Nateghi, Mohammad Reza Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

Breast cancer is a prevalent heterogeneous malignant disease. Gene expression profiling by DNA microarray can classify breast tumors into five different molecular subtypes: luminal A, luminal B, HER-2, basal and normal-like which have differing prognosis. Recently it has been shown that immunohistochemistry (IHC) markers including estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (Her2), can divide tumors to main subtypes: luminal A (ER+; PR+/-; HER-2-), luminal B (ER+;PR+/-; HER-2+), basal-like (ER-;PR-;HER2-) and Her2+ (ER-; PR-; HER-2+). Some subtypes such as basal-like subtype have been characterized by poor prognosis and reduced overall survival. Due to the importance of the ER signaling pathway in mammary cell proliferation; it appears that epigenetic changes in the $ER{\alpha}$ gene as a central component of this pathway, may contribute to prognostic prediction. Thus this study aimed to clarify the correlation of different IHC-based subtypes of breast tumors with $ER{\alpha}$ methylation in Iranian breast cancer patients. For this purpose one hundred fresh breast tumors obtained by surgical resection underwent DNA extraction for assessment of their ER methylation status by methylation specific PCR (MSP). These tumors were classified into main subtypes according to IHC markers and data were collected on pathological features of the patients. $ER{\alpha}$ methylation was found in 25 of 28 (89.3%) basal tumors, 21 of 24 (87.5%) Her2+ tumors, 18 of 34 (52.9%) luminal A tumors and 7 of 14 (50%) luminal B tumors. A strong correlation was found between $ER{\alpha}$ methylation and poor prognosis tumor subtypes (basal and Her2+) in patients (P<0.001). Our findings show that $ER{\alpha}$ methylation is correlated with poor prognosis subtypes of breast tumors in Iranian patients and may play an important role in pathogenesis of the more aggressive breast tumors.

Electrochemical degradation of the Acid Orange 10 dye on a Ti/PbO2 anode assessed by response surface methodology

Afshin Ebrahimi,Gholamreza Bonyadinejad,Mansour Sarafraz,Mohsen Khosravi,Seyed Mahmood Taghavi-Shahri,Roya Nateghi,Sedighe Rastaghi 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.1

The decolorization and degradation of the synthetic aqueous solution of the Acid Orange 10 (AO10) dye on Ti/PbO2 anode were investigated using the response surface methodology based on central composite design with three variables: current density, pH, and supporting electrolyte concentration. The Ti/PbO2 electrode was prepared by the electrochemical deposition method. The optimum conditions for AO10 decolorization in synthetic dye solution were electrolyte concentration of 117.04 mM, pH of 12.05, and current density of 73.64 mA cm−2. The results indicated that the most effective factor for AO10 degradation was current density. Furthermore, the color removal efficiency significantly increased with increasing current density. To measure AO10 mineralization under optimum conditions, the chemical oxygen demand (COD) and total organic carbon (TOC) removal were evaluated. Under these conditions, decolorization was completed and 63% removal was recorded for COD and 60% for TOC after 100 min of electrolysis.