The Effect of Local Fuse on Behavior of Concentrically Braced Frame by a Numerical Study

The concentrically braced frames (CBFs) are one of the most widely used lateral load-resisting systems. Seismic performance of these structures has a weakness that is due to the brace buckling at a lower loading than the ultimate compressive loading capacity. In this paper, attempt is made to enhance the seismic response of CBFs through utilizing a local fuse. For this purpose, first the formulation of fuse area and length are presented. Then based on this formulation, several numerical models have been built and analyzed to examine the effect of implementing this fuse on seismic response of CBFs. From the analyses results, it is found that if the reduced cross-section fuse (RCF) is properly designed and also the end of brace is fixed, the CBFs with equal energy dissipation capacity, that are equipped with this fuse exhibit a better ductility than the customary CBFs

Solving no-wait two-stage flexible flow shop scheduling problem with unrelated parallel machines and rework time by the adjusted discrete Multi Objective Invasive Weed Optimization and fuzzy dominance approach

Purpose: Adjusted discrete Multi-Objective Invasive Weed Optimization (DMOIWO) algorithm, which uses fuzzy dominant approach for ordering, has been proposed to solve No-wait two-stage flexible flow shop scheduling problem. Design/methodology/approach: No-wait two-stage flexible flow shop scheduling problem by considering sequence-dependent setup times and probable rework in both stations, different ready times for all jobs and rework times for both stations as well as unrelated parallel machines with regards to the simultaneous minimization of maximum job completion time and average latency functions have been investigated in a multi-objective manner. In this study, the parameter setting has been carried out using Taguchi Method based on the quality indicator for beater performance of the algorithm. Findings: The results of this algorithm have been compared with those of conventional, multi-objective algorithms to show the better performance of the proposed algorithm. The results clearly indicated the greater performance of the proposed algorithm. Originality/value: This study provides an efficient method for solving multi objective no-wait two-stage flexible flow shop scheduling problem by considering sequence-dependent setup times, probable rework in both stations, different ready times for all jobs, rework times for both stations and unrelated parallel machines which are the real constraints.Peer Reviewe

A Comparative Study on Using Meta-Heuristic Algorithms for Road Maintenance Planning: Insights from Field Study in a Developing Country

Optimized road maintenance planning seeks for solutions that can minimize the life-cycle cost of a road network and concurrently maximize pavement condition. Aiming at proposing an optimal set of road maintenance solutions, robust meta-heuristic algorithms are used in research. Two main optimization techniques are applied including single-objective and multi-objective optimization. Genetic algorithms (GA), particle swarm optimization (PSO), and combination of genetic algorithm and particle swarm optimization (GAPSO) as single-objective techniques are used, while the non-domination sorting genetic algorithm II (NSGAII) and multi-objective particle swarm optimization (MOPSO) which are sufficient for solving computationally complex large-size optimization problems as multi-objective techniques are applied and compared. A real case study from the rural transportation network of Iran is employed to illustrate the sufficiency of the optimum algorithm. The formulation of the optimization model is carried out in such a way that a cost-effective maintenance strategy is reached by preserving the performance level of the road network at a desirable level. So, the objective functions are pavement performance maximization and maintenance cost minimization. It is concluded that multi-objective algorithms including non-domination sorting genetic algorithm II (NSGAII) and multi-objective particle swarm optimization performed better than the single objective algorithms due to the capability to balance between both objectives. And between multi-objective algorithms the NSGAII provides the optimum solution for the road maintenance planning. © 2017 The Authors

A New Approach to the Optimal Placement of the Viscous Damper Based on the Static Force Distribution Pattern

Viscous dampers (VDs) are currently used an effective earthquake risk reduction measure. Due to the high cost of this type of dampers, an optimal damper layout across the stories will specifically improve the seismic response and reduce building costs. This paper introduces a new simple three-stage method to determine the optimal placement of VDs on different stories of reinforced concrete structures. In the first stage, the damping demand of each story was determined using the distribution pattern of earthquake forces by the equivalent static method and the story velocity obtained through time-history analysis. In the second stage, the number of dampers required for the structure was calculated, and the location and damping percentage of dampers were precisely determined through an iterative process in the third stage. An indicator representing all basic structural responses was used to evaluate the multiple choices for the damper layout. This process was evaluated for 4, 8 story concrete frames under a near-field earthquake. The results indicated the efficiency of the proposed method in determining the location and damping of VDs on different stories of the structure.

Evidence behind the use of molecular tests in melanocytic lesions and practice patterns of these tests by dermatopathologists

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146490/1/cup13327_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146490/2/cup13327-sup-0001-AppendixS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146490/3/cup13327.pd

Causal analysis of safety risk perception of Iranian coal mining workers using Fuzzy Delphi and DEMATEL

Underground coal mines, one of the most dangerous work environments, have experienced accidents and disasters. One of the main reasons for those unsafe events is the workers’ poor understanding of the hazards and risks of working in this work environment. Therefore, the present study aims to identify factors affecting the safety risk perception of underground coal mine workers in Iran and investigate their cause-and-effect relationships. By reviewing the literature, 40 variables were identified in five categories: individual, organizational, environmental, task, and external factors. The identified variables were ranked according to the expert group’s opinion in the form of a fuzzy Delphi study regarding their effects on risk perception. In the next step, 23 variables were selected to investigate the cause-and-effect relationships using the DEMATEL method. The study’s findings showed that organizational factors and some individual factors play a fundamental role in workers’ risk perception. The variables of safety culture, safety management style, and safety attitude had the most significant impact, and the variables of personal protective equipment and risk aversion had the smallest impact on workers’ risk perception. The present study’s findings can be used as a guideline to provide effective solutions for managers and workers in improving safety risk perception, subsequently reducing unsafe behaviors and increasing the safety status of underground coal mines.This research was funded by the KASHAN University of Medical Sciences and Health Services and grant number 140008257113.Peer ReviewedObjectius de Desenvolupament Sostenible::8 - Treball Decent i Creixement EconòmicPostprint (published version