Search results

Almost design code is required for repairability of the buildings after a major earthquake. One such idea is “directed-damage design” (DDD), which means guiding the damage to some pre-decided parts of the structural system. To use the DDD idea for creation of repairable buildings, in this study, a structural system with seesaw motion with respect to a central massive support has been considered for steel buildings with square plan, and the bottom ends of the all circumferential columns at the lowest story have been equipped with double-ADAS (DADAS) dampers, which dissipate a great portion of the seismic input energy. The purpose of this paper is to investigate the hysteretic behavior of DADAS dampers by using finite element analysis. At first, a set of regular steel multistory buildings with five stories have been designed based on the conventional code provisions. Then, the structures of the designed buildings have been changed into the structure with seesaw motion by using, at the base level of the building, a massive central column, eliminating other middle columns, and equipping circumferential columns with DADAS dampers.

For repairability buildings in the last three mentioned studies a set of orthogonal strong girders, in the form of grid, has been used. In the present study, the number of bays in the considered building is four in both directions. A major modification has been made in the yielding-plate energy dissipating elements of the circumferential columns, which makes their manufacturing and installation much practical as illustrated in the following sections of the paper.

In the proposed rocking structural system for regular multistory steel buildings, creation of the possibility of rocking motion has been done by using a space truss resting on a huge central hinge support at base level with a series of circumferential energy dissipating columns at that level.

One such idea is DDD idea, which means guiding the damage to some pre-decided parts of the structural system.

Scenario planning is a useful approach that helps policymakers to better understand the complexity and uncertainties that lie in the future and to choose the right policy mix to support the development of renewable and affordable energy sources. In this regard, this paper aims to present renewable energy (RE) development scenarios in Iran in the horizon of 2030.

Following the intuitive logic school and the Global Business Network model, the authors identified seven driving forces, according to the expert’s judgment, by brainstorming techniques which influence REs development in the horizon of 2030. By prioritizing driving forces based on their importance and uncertainty, “sustainable and green economy” and “emerging technology development” are the most instrumental uncertainties and the authors formed a two-axis scenario matrix with each representing an axis.

The results suggest four main scenarios of “Transition to Sustainability with Green Gold,” “Towards Sustainability with Green Gold,” “Productivity with Black Gold” and “Desperation with Black Gold.” They include a wide range of possible situations of energy basket in the future ranging from dominance of fossil fuels to dominance of REs. The “Productivity with Black Gold” and the “Towards Sustainability with Green Gold” are the most probable scenarios of RE development by 2030 in Iran.

This paper indicates that the dominance of oil and gas resources would impede or at least slow down the development of renewable and affordable energy sources. Although the economic and environmental potentials and the inevitability of REs are well-understood, path dependence created by fossil fuels in Iran’s energy regime, either partially or fully, hinders the widespread development of REs which is the case in other resource-based countries as well.

Domestic refrigerators could be considered as one of the major potential sources of food-borne diseases, in addition limited data are available regarding the level of contamination of domestic refrigerators in Iran. The purpose of this paper is to detect some of bacterial contamination in domestic refrigerators.

In total, 104 households were randomly selected from ten health centers in five areas of Tehran, Iran. Visual inspection and temperature evaluation of the households’ refrigerators were done. In addition, the refrigerators were swabbed and analyzed for contaminants using polymerase chain reaction (PCR) method. DNA was isolated and purified by the proposed standard protocol.

Screening of the domestic refrigerators by PCR method showed that 51.7 percent of the samples were positive for pathogens as follows: L. monocytogenes 41.6 percent, S. aureus 5.5 percent, Salmonella spp 4.6 percent, and E. coli O157:H7 0 percent; consequently, none of mentioned pathogens were detected in 48.3 percent of the refrigerators. Results of the visual inspection indicated that 57 percent of the refrigerators were on desirable, 36.5 percent were acceptable, and 7 percent were weak conditions. Most of the refrigerators about 44 percent had desirable temperatures. There were no significant correlations between the visual inspection scores, temperature and frequency of isolation of specific pathogens in the domestic refrigerators. A significant correlation was observed between contamination and education of parents (p < 0.05).

Determination of the bacterial contamination and evaluating the temperature of domestic refrigerators in Iran can be considered as a novel approach of current study. These findings could be employed in designing and implementing appropriate educational interventions to promote food safety and diminish the risk of food-borne illnesses. Also, obtained results might be applied as introduction for further investigations.