نشریه هوزان
سال یکم شماره 4 (امرداد و شهریور 1395)

Tehran has special geographical conditions¡ different aspects of ecological and pollu-tants¡ is of considerable importance. On the other hand¡ algae¡ specifically the diatoms firsts in ecological indicators¡ including natural and man-made environment are accounted for.
Samples of algae as well as a report documenting of the various localities of Tehran during the last half century were systematically surveyed and basic information was classified. A variety of harmful algae with parameters such as disruption of water supply networks¡ parasitism¡ creating mud¡ wa-ter color change¡ adhesion to walls¡ concrete or metal structures¡ taste and unpleasant odor were evaluat-ed. In addition¡ different types of algae with the ability to monitor for contamination of soil and water resources in urban and industrial wastewater in various parts of Tehran were studied.
in order to analyzing the data including text¡ description and digital¡ by using electronic identi-fication algorithm (EID) a comprehensive software model was designed and developed. By Data pro-cessing about the biodiversity of algae which have been reported from Tehran province¡ 314 IDs were belong to four concatenation of Chromista¡ Eubacteria¡ Plantae and Protozoa were identified.
In a comparative study of algae diversity of Tehran¡ similarity with 21 other provinces is noticeable. Thus¡ according to simple structure but powerful of the proposed model¡ this technology can be used in other localities of the country.

Today The oil and gas industry due to many industrial activities and lots of workers are the largest industries in the world. Coastal and offshore installations in terms of these two factors have a large share among oil facilities. Available Data in relation to the assessment of systemic exposure to chemical materials on offshore facilities are limited or related to the past few years. The purpose of this study was to assess the risks of exposure to chemicals on an oil platform.
In this study the method of the Risk assessment of chemical material of Singapore National In-stitute of Safety and Health is used .in this method Firstly job tasks and work process was determined by interviewing then identifying chemical agents in each of the job was done accurately. Then¡ hazard rate¡ exposure rate and health risk level caused by exposure to chemicals was determined.
Based on the result of the working group study and investigation of documentation processing was found that on the investigated oil platform¡ workers had the maximum exposure to H2S¡ BTEX and gasoline vapors. In the repairs unit¡ the highest level of risk caused by benzene and on the floor the genera-tors and oil wells unit caused by hydrogen sulfide.
By importing information relating to risks and results of the chemical materials measure-ments in the chemical risk assessment method could rank the various jobs and tasks in terms of exposure to chemicals. This result will be used to prioritize control measures and reduce the level of risk. According to the results of this study the establishment of control systems to reduce the risks of BTEX compounds and hydrogen sulfide is recommended.

The basic objective in the planning of leisure - tourism is the createation of the most desir-able balance sustainable in long-term between recreational resources limited, and the willingness and Recre-ational demands of user. Increasing recreational needs, reveals the need to appropriate places for recrea-tional activities. Shivand area because of Shivand falls in case studies in province Khuzestan has great envi-ronmental value. Valuation economic - tourism in Shivand is step towards achieving development sustaina-ble in this region.
In this study, to identify the economic - tourism value in Shivand area Clawson method is used. This method is based on relationship between the number of visitors and the average distance residential of this people of the area and also based on the use of the map, preferences and social and economic charac-teristics recreational area and the relationship between cost of access and the number of visitors, by consid-ering available information. Then the demand curve is made by considering the hypothetical fees and new ratio of visitors on the basis of questionnaires.
Calculations showed that estimated economic - tourism value of Shivand area, on summer of 1394 was every day 30,000 £. The results showed that variables such as age, education level and monthly income of visitors had a significant impact on the promenade. Also the results showed that highest number of visitors aged 20 to 30 years old. The daily economic value of promenade on the basis of demand was 30 million toman and the cost-benefit ratio was 4.99997115. The relationship between the level of monthly income with the number of days outing in nature showed that the correlation coefficient between these two variables equal to 0.9, calculate the correlation coefficient between income and willingness to pay the hy-pothetical fee 0.92, the correlation between two variables the cost of travel and the number of visitors equal to -0.9 and the relationship between the distance of the promenade and the number of visitors shows that the correlation coefficient between these two variables is equal to -0.96.
According to the results of visitors mentioned main motivation to visit the park is just for lei-sure and recreation with percent frequency of 37.52, which represents the targeted visitors and need and high demand of the community members, compared to the resorts.

hydroelectric dams are the most serious damage to the environment¡ this damages are rec-orded clearly in the past decade. However¡ many countries around the world¡ emphasize on hydroelectric dams in order to supply the bulk of electricity. The Electricity is a key factor for improving the lives of people around the world. In developing countries¡ increase of rapid urbanization and growth population¡ would increase the demand for electricity in the next decades¡ even with the most successful demand man-agement and energy efficiency proceedings. Energy planners in many developing countries believed in keeping on the construction of hydroelectric dams as a sustainable source of electricity.
This paper presents important recommendations for decreasing the significant environmental damage of hydroelectric dams through proper site selection. Although primarily intended dams are Latin America dams¡ but environmental and social robust criteria and quantitative indicators¡ used is useful in all over the world. As such¡ this article interesting to whom interested in hydroelectric dams¡ government agen-cies¡ private companies¡ energy companies¡ environmental consulting and other non-governmental organiza-tions and universities. This article is a part of the environmental and social published reports of Latin Amer-ica and the Caribbean regional sustainable development management.
Before environmental analysis before dam site selection can rank potential sites according to their degree of environmental desirability. In This paper 13 quantitative indicators for site selectionehich is calculated easily from environmental indicators are obtained. This indicators are such as : reservoir surface area¡ water retention time in reservoir¡ biomass flooded¡ length of river impounded¡ length of river left dry¡ number of downriver tributaries¡ likelihood of reservoir stratification¡ useful reservoir life¡ access roads through forests¡ persons requiring resettlement¡ critical natural habitats affected¡ fish species diversity and endemism¡ cultural property affected.
In general¡ the most environmentally friendly of hydroelectric dam sites locate up streem¡ while the most problematic ones locate on main branch of rivers.

Abstract
Termites need to thermal regulation inside their nest for survive. Therefore¡ termite mound¡ as a skin between termites and environment¡ perform this mechanism in different form. This paper investi-gates the role of environment in shaping of the variety of the termite mounds in order to remain temperature in building.
In this way termite mound buildings were studied through biological studies. The subject of this study is about termite mounds that distributed in arid area with important mechanism in thermal regulation. This data investigated from architecture features in different climate land¡ then physical difference between them explored and cause of this variety explained. There are biology and climate studies as tools of re-search that surveyed on base of energy knowledge.
Although various forms in building termite mound is not only due to climatic variations¡ but this diversity dependent on environmental characteristics of temperature¡ humidity and solar radiation. In other words¡ shape of building termite mound is constructed with their surroundings. This climate features in hot and cold area gives different effects on height¡ orientation¡ volume and shape of termite mound.
The results show that a variety of forms¡ deal with its surrounding environment and does not cause the main function of the mound. Also Ecosystems have important effect in shape of termite mound in different areas.