Soft story retrofit of low-rise braced buildings by equivalent moment-resisting frames

Parviz Ebadi,Ahmad Maghsoudi,Hessam Mohamady 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.68 No.5

Soft-story buildings have bottom stories much less rigid than the top stories and are susceptible to earthquake damage. Therefore, the seismic design specifications need strict design considerations in such cases. In this paper, a four-story building was investigated as a case study and the effects of X-braces elimination in its lower stories studied. In addition, the possibility of replacement of the X-braces in soft-stories with equivalent moment resisting frame inspected in two different phases. In first phase, the stiffness of X-braces and equivalent moment-resisting frames evaluated using classic equations. In final phase, diagonals removed from the lowest story to develop a soft-story and replaced with moment resisting frames. Then, the seismic stiffness variation of moment-resisting frame evaluated using nonlinear static and dynamic analyses. The results show that substitution of braced frames with an equivalent moment-resisting frame of the same stiffness increases story drift and reduces energy absorption capacity. However, it is enough to consider the needs of building codes, even using equivalent moment resisting frame instead of X-Braces, to avoid soft-story stiffness irregularity in seismic design of buildings. Besides, soft-story development in the second story may be more critical under strong ground excitations, because of interaction of adjacent stories.

Determination of Copper in Black, Red Pepper and the Waste Water Samples by a Highly Selective Sensitive Cu(II) Microelectrode Based on a New Hexadentates Schiff's Base

Parviz Norouzi*,Mohammad Reza Ganjali,Farnoush Faridbod,Masoud Salavati-Niasari 대한화학회 2006 Bulletin of the Korean Chemical Society Vol.27 No.9

A Cu2+ ion-selective membrane microelectrode has been fabricated from poly vinyl chloride (PVC) matrix membrane containing a new symmetrical hexadentate Schiff,s base 2-{1-(E)-2-((Z)-2-{(E)-2-[(Z)-1-(2-hydroxyphenyl)ethylidene]hydrazono}-1-methylpropylidene)hydrazono]ethyl}phenol (HDNOS) as a neutral carrier, Potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic excluder and o-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator. The microelectrode displays linear potential response in the concentration range of 1.0 10-5-1.0 10-11 M of Cu2+. The microelectrode exhibits a nice Nernstian slope of 25.9 0.3 mV decade-1 in the pH range of 3.1-8.1. The sensor has a relatively short response time in whole concentration ranges (~5 s). The detection limit of proposed sensor is 5.0 10-12 M (320 pg/L), and it can be used over a period of eight weeks. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of Cu2+ with EDTA. The proposed membrane electrode was used for the direct determining of Cu2+ content in black and red pepper, and in waste water samples.

Critical Thinking Skills of the Students in Bushehr University of Medical Sciences

Parviz Azodi,Faezeh Jahanpour 한국간호과학회 2009 한국간호과학회 학술대회 Vol.2009 No.10

Multi-objective optimization of friction stir welding using Taguchi design method, response surface model and particle swarm algorithm

Parviz Kahhal,Mohsen Ghasemi,Mohammad Kashfi,Ji Hoon Kim(김지훈) 한국자동차공학회 2021 한국자동차공학회 부문종합 학술대회 Vol.2021 No.6

Effect of rheumatoid arthritis on periodontitis: a historical cohort study

Parviz Torkzaban,Tayebeh Hjiabadi,Zahra Basiri,Jalal Poorolajal 대한치주과학회 2012 Journal of Periodontal & Implant Science Vol.42 No.3

Purpose: Rheumatoid arthritis (RA) is a chronic multi-systemic disease that causes damage to the bone and connective tissues. This study was conducted in order to accurately measure the correlation between RA and periodontitis, and to obtain an unbiased estimate of the effect of RA on periodontal indices. Methods: In this historical cohort study, which was conducted from February to May 2011 in Hamadan city, Iran, 53 exposed people (with RA) were compared with 53 unexposed people (without RA) in terms of clinical periodontal indices (the outcomes of interest) including 1) plaque index (PI), 2) bleeding on probing (BOP), and 3) clinical attachment loss (CAL). Results: A sample of 106 volunteers were evaluated, 53 rheumatoid versus 53 non-rheumatoid subjects. There was a statistically significant correlation between RA and BOP (P<0.001) and between RA and CAL (P<0.001). However, there was no statistically significant correlation between RA and any of the periodontal indices. No correlation was seen between gender and any of the indices either. There was a strong positive correlation between age and all three periodontal indices (P<0.001). Conclusions: The present study indicated a potential effect of RA on periodontal indices. However, much more evidence based on a prospective cohort study is needed to support the cause and effect relationship between RA and periodontal indices.

Lexical Chains or Semantic Networks as Effective Top-down Pre-reading Activities

Parviz Ajideh 아시아영어교육학회 2007 The Journal of Asia TEFL Vol.4 No.4

Bi-level optimization of laminated composite structures using particle swarm optimization algorithm

Parviz Mohammad Zadeh,Mahdi Fakoor,Mostafa Mohagheghi 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.4

This paper presents an efficient bi-level optimization technique to obtain the optimal stacking sequence for symmetric composite structures. The proposed approach involves two levels of modelling and optimization. The first level of the optimization procedure is used to minimize the weight of the composite structure. At this level, lamination parameters and the number of plies of specified angles (0, ±45 and 90 degree) are design variables, buckling load factor is treated as a constraint, and the weight of the structure is to be minimized using continuous-discrete particle swarm optimization algorithm. Next, at the second level the location of each ply orientation through the thickness (i. e. the layup of the panel) is found. At the second level, optimum stacking sequence is sought to maximize the load bearing capacity of the structure with respect to the buckling. The proposed methodology is applied to two test cases. Results show that the approach improves the buckling load factor of the structure without any weight penalty.

A Risk-Oriented Buffer Allocation Model Based on Critical Chain Project Management

Parviz Ghoddousi,Ramin Ansari,Ahmad Makui 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.5

In this study, a multi-attribute buffer sizing method is proposed aimed at maximizing the robustness of the buffered schedule generated. The project attributes concerning the network complexity, flexibility criteria, criticality index and robustness measures are considered through the buffer sizing process. The methodology presented is based on the critical chain buffer management methodology, yet innovative metrics are presented to deal with the uncertainties associated with the critical and non-critical chains. The buffer sizing method proposed eliminates the previous limitations and attempts to economically determine the size of the feeding and project buffers. Additionally, a risk analysis is performed to examine the effects of external factors on buffer sizes. The weaknesses of the existing buffer sizing approaches were overcome in the critical chain project management, and a novel buffer sizing method was established based on internal and external risk aspects. A simulation experiment is conducted in order to prove the effectiveness of the method proposed. The computational results of implementing the method on a real case study specify that the method proposed generates more stable project plans at a lower cost, compared with those generated using traditional buffer sizing methods.

An improved modal strain energy method for structural damage detection, 2D simulation

Parviz Moradipour,Tommy H.T. Chan,Chaminda Gallage 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.1

Structural damage detection using modal strain energy (MSE) is one of the most efficient and reliable structural health monitoring techniques. However, some of the existing MSE methods have been validated for special types of structures such as beams or steel truss bridges which demands improving the available methods. The purpose of this study is to improve an efficient modal strain energy method to detect and quantify the damage in complex structures at early stage of formation. In this paper, a modal strain energy method was mathematically developed and then numerically applied to a fixed-end beam and a three-story frame including single and multiple damage scenarios in absence and presence of up to five per cent noise. For each damage scenario, all mode shapes and natural frequencies of intact structures and the first five mode shapes of assumed damaged structures were obtained using STRAND7. The derived mode shapes of each intact and damaged structure at any damage scenario were then separately used in the improved formulation using MATLAB to detect the location and quantify the severity of damage as compared to those obtained from previous method. It was found that the improved method is more accurate, efficient and convergent than its predecessors. The outcomes of this study can be safely and inexpensively used for structural health monitoring to minimize the loss of lives and property by identifying the unforeseen structural damages.

Length of Curcumin Supplementation on Antioxidant Capacity of Adolescent Taekwondo Players

( Parviz Ahmadi ),( Fareba Rahpeyma ),( Naser Bageri ) 국제태권도학회 2017 International Symposium for Taekwondo Studies Vol.2017 No.-

Purpose: This study investigated the influence of length of curcumin supplementation on antioxidant capacity in adolescent Taekwondo players during short-term tournaments. Methods: For this purpose, 30 adolescent taekwondo players (age: 15.13 ± 2.96 yrs, height: 173.17 ± 7.29 cm, weight: 59.82 ± 10.83 kg) were assigned randomly to three groups: (middle-term group: n = 10, short-term group: n = 10, placebo group, n = 10). The middle-term group received 140 mg of curcumin 48 hrs before the tournament, and the short-term group received 70 mg of curcumin between competitions (three 10-min. matches with 1-hour intervals). The placebo group received a placebo 48 hrs before and between competitions. One hour following the last match, blood samples were collected and used to determine antioxidant enzymes (GPX and CAT enzymes) activity and MDA levels. Results: ANOVA results showed that GPX activity (U/mg pro) in middle-term group increased significantly (p = 0.0001), whereas there was no significant difference in CAT activity (U/mgpro) (p = 0.098). Also, there was no significant differences in MDA level (Nmol/ml) between all 3 groups (p = 0.437), but it was insignificantly lower in the middle-term group compared to the short-term group and lower in both of the middle-term and short-term groups in comparison with the placebo group. Conclusions: These findings suggested that curcumin consumption 48 hrs before short-term competitions may affect Taekwondo players’ antioxidant enzymes concentration and promote the antioxidant capacity in adolescent athletes during heavy competitions. This strategy can accelerate recovery from repeated stresses during short-term tournaments.