A Comparative Study on the Behavior of Steel Moment-Resisting Frames with Different Bracing Systems Based on a Response-Based Damage Index

Seismic rehabilitation of existing buildings is one of the most effective ways to reduce damages under destructive earthquakes. The use of bracings is one of techniques for seismic rehabilitation of steel structures. In this study we aimed to investigate the seismic performance of three 5, 10 and 15-storey steel structures with moment-resisting frames designed three dimensionally in ETABS 2015 application based on first edition of Iranian Standard 2800. Their damage under five ground motions was evaluated using response-based damage model proposed by Ghobara et al. (1999). Then, the structures were rehabilitated with different bracing systems (X, eccentric and concentric V and inverted-V) and, again, their damage under five earthquakes were evaluated and compared with those of moment resisting frames. The pushover analysis results indicated that X-braced frame was the least ductile system but had highest initial stiffness and yield stress. In low-rise building, X-braced frames showed better performance among studied bracing systems compared to moment resisting frames, while mid and high-rise buildings with eccentrically braced  frame (EBF) showed the best behavior against earthquakes with the least damage. Moreover, it was found out that EBFs’ performance increases by increasing storey height, but for concentrically braced frames (CBFs) it was decreased. We concluded that the use of response-based damage models can be a suitable procedure for estimating the vulnerability of steel structures rehabilitated with bracing system

Study on the dynamic behavior of cylindrical steel liquid storage tanks using finite element method

Dynamic behavior of ground supported cylindrical storage tanks (CST) is of crucial importance because of its applications in industrial complexes. Seismic behavior of tanks is greatly affected by the height to diameter ratio, fluid height and fluid type. Five CSTs with different height to diameter ratios, three CSTs with the same height and diameters but various fluid heights and one CST with two different fluid types are selected to determine the effect of height to diameter ratio, fluid heights, and fluid type on the seismic behavior of the tanks respectively. Static, modal, response spectrum, and time history analyses are used in this study for the selected CSTs using ANSYS finite element software. In the time history analysis method, the Tabas, Kobe and Cape Mendocino earthquake records have been utilized on the first five CSTs to ascertain the effect of height to diameter ratio and the Tabas earthquake record is used for the rest of CSTs. Results show that an increase in fluid height lead to a corresponding increase in the base shear. Based on observations, 100 percent increase in the diameter showed 63 percent increase in sloshing under the response spectrum and 70 percent under time history analyses. Based on static and response spectrum analyses, the highest values of displacements are obtained at the lowest part of the tanks, while in time history analysis, the highest is obtained at the top of the tanks. All analyses showed that the maximum stress occurred at the height of 1 to 2 meter from the bottom of the tanks

Numerical investigation of hemodynamic performance of a stent in the main branch of a coronary artery bifurcation

Introduction: The effect of a bare-metal stent on the hemodynamics in the main branch of a coronary artery bifurcation with a particular type of stenosis was numerically investigated by the computational fluid dynamics (CFD). Methods: Three-dimensional idealized geometry of bifurcation was constructed in Catia modelling commercial software package. The Newtonian blood flow was assumed to be incompressible and laminar. CFD was utilized to calculate the shear stress and blood pressure distributions on the wall of main branch. In order to do the numerical simulations, a commercial software package named as COMSOL Multiphysics 5.3 was employed. Two types of stent, namely, one-part stent and two-part stent were applied to prevent the build-up and progression of the atherosclerotic plaques in the main branch. Results: A particular type of stenosis in the main branch was considered in this research. It occurred before and after the side branch. Moreover, it was found that the main branch with an inserted one-part stent had the smallest region with the wall shear stress (WSS) below 0.5 Pa which was the minimum WSS in the main branch without the stenosis. Conclusion: The use of a one-part stent in the main branch of a coronary artery bifurcation for the aforementioned type of stenosis is recommended

Numerical investigation of the blood flow through the middle cerebral artery

Introduction: The middle cerebral artery (MCA) is one of the three major paired arteries that supply the blood to the cerebrum. In the present study, the three-dimensional (3D) blood flow in the left MCA was numerically simulated by using the medical imaging. Methods: The arterial geometry was obtained by applying the CT angiography of the MCA of a 75-year-old man. The blood flow was assumed to be laminar and unsteady. Numerical simulations were done by commercial software package COMSOL Multiphysics 5.2. In this software, the Galerkin’s finite element method was applied to solve the governing equations. Results: It was found that the results obtained for the Newtonian and non-Newtonian models of blood do not differ from each other significantly. Thus, the Newtonian model for blood flow in the MCA is acceptable. Also, the most susceptible region of the MCA for Atherosclerosis was detected. Conclusion: It can be concluded that the application of the Newtonian model for the blood flowing in the MCA is acceptable. Also, atherosclerosis has the potential to occur at the middle of a branch of the MCA which has the highest geometrical curvature

MERCURY: Accelerating DNN Training By Exploiting Input Similarity

Deep Neural Networks (DNN) are computationally intensive to train. It consists of a large number of multidimensional dot products between many weights and input vectors. However, there can be significant similarity among input vectors. If one input vector is similar to another, its computations with the weights are similar to those of the other and, therefore, can be skipped by reusing the already-computed results. We propose a novel scheme, called MERCURY, to exploit input similarity during DNN training in a hardware accelerator. MERCURY uses Random Projection with Quantization (RPQ) to convert an input vector to a bit sequence, called Signature. A cache (MCACHE) stores signatures of recent input vectors along with the computed results. If the Signature of a new input vector matches that of an already existing vector in the MCACHE, the two vectors are found to have similarities. Therefore, the already-computed result is reused for the new vector. To the best of our knowledge, MERCURY is the first work that exploits input similarity using RPQ for accelerating DNN training in hardware. The paper presents a detailed design, workflow, and implementation of the MERCURY. Our experimental evaluation with twelve different deep learning models shows that MERCURY saves a significant number of computations and speeds up the model training by an average of 1.97X with an accuracy similar to the baseline system.Comment: 13 pages, 18 figures, 4 table

The Relationship between Blood Lead Levels and Clinical Features among Multiple Sclerosis Patients in Isfahan, Iran

Lead (Pb) is one of the most likely toxicants that could be potentially a risk factor in the development of Multiple Sclerosis (MS) through changes in the immune system. The purpose of the study was to describe the clinical features of MS in general and for sub-groups stratified for gender, age, residence, disease duration, disability degree, clinical diagnosis in Isfahan, Iran and also, to elucidate the relationship between the blood Pb level and the development of MS. Blood samples of 48 patients (20 to 57 years) were selected from the department of neurology of the Kashani hospital in Isfahan, Iran and were analyzed for Pb using anodic stripping voltammetry (ASV). The clinical and demographic characteristics in our study were similar to those in other reports. The blood Pb level in 70.83% of the total population wa

Comparative analysis of agricultural water pricing between Azarbaijan Provinces in Iran and the state of California in the US: a hydro-economic approach

Iranian water authority has recently announced that one of the effective ways to avoid unprecedented high water consumption in Iran’s agriculture sector is to increase water price. This paper analyzes the feasibility of this policy by using a hydro-economic approach with the aim to consider the role of water pricing in agricultural water management. Such an analysis was conducted through comparing price of water consumed for producing selected agricultural crops (i.e. wheat, sugar beets, onion, tomato, barley, potato, corn, alfalfa hay and watermelon) in a case study on two provinces (East Azarbaijan and West Azarbaijan) in Iran to that in the state of California (CA) in the USA. According to the paper, the method uses the Purchasing Power Parity (PPP) Index for the first time to analyze the water prices of agricultural crops in the case study due to the specific regional circumstances in the Case Study (i.e. severe fluctuations and continuously changing currency) that prevent using the norm of Nominal Exchange Rate Index (NERI). The results show there is no significant difference between the water price for producing the selected crops in West Azarbaijan (W.AZ) and East Azarbaijan (E.AZ) provinces and that in the state of California if PPP Index is applied. Water price for producing each kilogram of some crops such as wheat, sugar beet, onion and watermelon (except potato and barley) is estimated to be between 60–80 percent of that in the state of California. However, this ratio is ironically equal to 116% for alfalfa hay and 105% for corn. As a result, considering the obtained results, one may realize that the whole problem can be hardly attributed to the low price of agricultural water in our case study and raising agricultural water price would never be effective for reducing water consumption in the studied area unless price adjustment accompanies developing necessary infrastructures. Unlike the views that advocate raising water prices, there are two distinct views: The first declares that agricultural water should be free of charge to the farmers because it returns to the hydrological cycle. The second view stipulates that instead of raising water prices in agriculture sector, the cost of water supply for agriculture should be reduced by new technologies. It is advised that before adjusting agricultural water price, institutional reforms are required based on the experiences of other countries and establishing local water distribution cooperatives