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

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

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.

FLOW MEASUREMENTS IN THE EXHAUST SYSTEM OF A MOTORIZED ENGINE

Parviz Merati,Arman Mirhashemi,Claudia Fajardo-Hansford,Tianshu Liu 한국자동차공학회 2017 International journal of automotive technology Vol.18 No.4

Stereo Particle Image Velocimetry (SPIV) is used to measure the highly turbulent flow in the upstream region of the catalytic converter for a four stroke IC engine. These experiments are conducted for a motorized engine to investigate the feasibility of using SPIV for exhaust flow measurements in a firing IC engine in our future research. The results obtained here can also be used for validation of the CFD models. The measured flow is highly three dimensional, non-uniform with large magnitudes of turbulence indicating recirculating flow structures. These structures show signatures of jet flows coming out of the exhaust valves at all exhaust crank angles. The triangular shape and location for the end face of each exhaust runner pipe, the length and geometry of the runners also affect the flow mixing process upstream of the catalytic converter contributing to the complexity of this flow. Although majority of the exhaust flow passes through the catalytic converter, some will recirculate due to impingement of the exhaust jets on the surface of the catalyst.

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.

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.

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

Nonenzymatic Glucose Biosensor Based on NiNPs/Nafion/graphene Film for Direct Glucose Determination in Human Serum

Parviz Sukhrobov,Sodik Numonov,Sanshuang Gao,Xamxikamar Mamat,Thomas Wagberg,Yufen Guo,Liwei Liu,Guangzhi Hu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.7

This study describes a type of novel nickel nanoparticles (NiNPs) decorated on Nafion-graphene composite film by using the electrochemical deposition method. It was used to fabricate electrochemical biosensors for sensitive nonenzymatic glucose detection. Compared with the Nafion–graphene film and NiNPs-modified glassy carbon electrode (NiNPs-GCE), the NiNPs/Nafion/graphene/GCE showed the best electrocatalytic activity towards glucose oxidation in alkaline medium. The NiNPs/Nafion/graphene/GCE at an applied potential of +0.55V in a linear range of 1–200 μM presented a high sensitivity of 3437.25 μA·mM -1 cm -2 with coefficient of correlation R2 = 0.999; and in a linear range of 200–10 800 μM it performed the best sensitivity of 2848.6 μA·mM -1 cm -2 with coefficient of correlation R2 = 0.995 towards glucose oxidation. For a concentration up to 200 M, a linear range was obtained with a limit of detection of 0.6 μM (signal to noise = 3) and as much as 10 800 μM with a limit of detection of 0.82 μM (signal to noise = 3). The time of responses was about 1–1.5 s with the addition of 0.1–1mM glucose. In addition, NiNPs/Nafion/graphene/GCE also has a high anti-interference ability toward common oxidative interfering species, such as uric acid, ascorbic acid and dopamine. More importantly, NiNPs/Nafion/graphene/GCE was successfully used for the determination of glucose concentration in human serum samples in comparison with a local hospital. The NiNPs/Nafion/graphene/GCE exhibited high sensitivity, low working potential, good stability, excellent electrical properties, enhanced selectivity and fast amperometric responses to glucose oxidation. Thus, as a nonenzymatic sensor, it is promising for future glucose determination development.

Guided Local Buckling (GLB) Theory for Short Braces

Parviz Ebadi,Saeid Sabouri-Ghomi 한국강구조학회 2012 International Journal of Steel Structures Vol.12 No.2

According to recent earthquake experiences and experimental results, the local buckling is the most important parameter for limiting the ductility of short braces and prevents earthquake energy absorption in larger drifts. A new theory is introduced to prevent harmful effects of local buckling and use it as an energy absorption device in braced frames. According to this theory oblique stiffeners are provided inside braces section and it is expected to divide lateral drift of the system to smaller deflections inside stiffeners intervals. As much as number of local buckling along braces increases, more energy will be absorbed and the fracture life of the sections increases considerably. This theory is supported by half-scale experimental results and numerical modeling. The obtained results represent uniform and stable energy absorption and reasonable system ductility.

Measurement of Bus Terminal Noise and Passengers’ Perception of Noise Impacts in Kuwait

Parviz A. Koushki 한국소음진동공학회 2003 한국소음진동공학회 국제학술대회논문집 Vol.2003 No.8