Introduction: Urbanization is increasing in the world and the world's urban population is becoming denser in cities. One of the effects of urbanization is the increase in the percentage of impervious surfaces in these areas. Today, many important cities in the world pay attention to the concept of sustainable development in order to reduce the effects of their city development on the quality and quantity of runoff and use modern green management technologies, including the best management methods and development methods with minimal side effects. A green roof is a multi-layered system that covers the roof and balcony of a building with vegetation and by absorbing and keeping part of the rain, and by influencing the processes of evaporation and transpiration, purification, the volume and intensity of the peak flow of runoff, the dimensions The drainage system reduces the downstream and improves the quality of air and water, preserves the beauty of the city and prevents the wastage of building energy. Material and methods: This research was conducted as a field experiment in the Faculty of Agriculture of Zanjan University. The test period was from April to August of 2017. In this research, the effect of the use of super absorbent (zeolite) on the amount of water absorption and retention, the maximum and minimum volume of runoff, the volume of runoff, sediment and the start time of the runoff resulting from rainfall in the rain intensity of 35, 45, 55, 65 and 75 mm/h has been investigated on a green roof with a slope of 5%, in a cold dry climate. Results and discussion: Based on this, with the increase in the intensity of rainfall, the volume of runoff also increases, and the volume of runoff in barren soil is more than the rest of the treatments, and its downward trend is soil containing 1% zeolite, soil containing 3% zeolite, and cultivated soil. Be Also, the volume of runoff increased with the increase in rainfall intensity and the highest value of runoff volume belongs to barren soil. The sediment measured in the runoff also increases with the increase in the intensity of precipitation in the treatments, except for the grass treatment. Conclusion: Barren soil has a very high volume of runoff due to the sealing of its surface layers and clogging of pores. Adding zeolite to the soil significantly reduced the volume of runoff and retained more water than barren soil. The rate of erosion in soil with 1% zeolite was high and the rate of erosion was the lowest in grass. In barren soil, because the penetration of water is low, after a short period of time after the rain, the water flows as runoff, but zeolite has the property and characteristic that when added to the soil, the time for the start of runoff is lengthened by 3%.

First roof weighting interval in mechanized longwall mining is related directly to the applied loads on support system and thus, has important role on stability, safety, and continuity of operation. This paper presents an innovative approach based on cavability of immediate roof to estimate first roof weighting interval. Nine inherent parameters of roof strata and its surrounding environment which affect caving process were taken into account to develop a classification system, incorporating fuzzy hybrid multi criteria decision-making technique. roof Strata Cavability index (RSCi) was defined as summation of ratings for all parameters. Subsequently, the relationship between RSCi and extracted volume until the first caving moment (i. e. the extraction height× panel width × first roof weighting interval) was determined using linear and non-linear regression models. Models were proposed and validated using the actual field data collected from different longwall panels around the world. Results indicated that the quadratic polynomial model gave a better performance in the estimation of first roof weighting interval, compared to the other models. It was concluded that the proposed approach is an accurate and flexible tool to estimate first roof weighting interval in longwall mining.

In Iran, some 22 percent of the building energy dissipates through the roof. In the hot arid parts of the country, most of this energy is used for cooling rather than heating. There are several methods for reducingthis energy loss. Insulation is one popular method throughout the world. A more effective method is to reduce the energy penetrating the building by means of cooling the roof. There are three main techniques for obtaining a “cool roof”. In the first method, heat loads are reduced by lightening the color of the roof, hence increasing its albedo. In the second method, the “green roof”, the roof is suffused with vegetation, which is more expensive and technically complicated. In the third method, the roof is sprinkled with water. In this method, a significant amount of water is wasted, however. Because of its inexpensiveness and simplicity, the first method was chosen for an experiment, in which part of a dark green roof was repainted with brilliant light green. The daily summer temperatures were then measured on an hourly basis and compared with the shaded areas of the roof as well as areas covered by plants. The results indicated that the repainted areas were about 17 percent cooler.

ABSTRACT Today, climate change and its obvious negative effects on ecosystems have caused concern. This research seeks to test whether vegetation changes are sensitive to climate shocks and also how the ecosystem recovery process is through this index. In this regard, by using the GEE platform, Java coding, GIS and statistical analysis, vegetation and Palmer indices were calculated and based on time series climate data, vegetation and climate changes were presented. The results of Palmer's drought index show that during the statistical period (1985-2020) the study area is facing drought or is moving towards drought. Also, the results indicate the longest period of drought in the region from 2013 to 2020. Totaly from 420 evaluated months, the NDVI index is below the change threshold in 70 months. Among these, 31 months of the study period is below the acceptable threshold in green and non-reservoir seasons, which is ecologically worrying. The distribution of the vegetation index based on hexagons in 1985 and 2005 had a normal and almost normal distribution; But in 2020, the graph deviated from the normal state and skewed towards the vegetation cover index under stress or even thin covers. According to the analysis of the indicators, it is predicted that the Gorgan region is on the border of such ecological developments and the historical ecosystem of the region is moving towards new ecosystems or being in a new equilibrium state with climatic conditions and human disturbances Extended Abstract Introduction Today, climate change and its obvious negative effects on terrestrial ecosystems have caused great concern to humans. These changes are effective on vegetation performance, plant distribution patterns, and have economic and environmental consequences. Therefore, it is important to know the behavioral pattern of vegetation changes against climate changes. Reviewing the studies of scientists in the world shows many researchers have used the NDVI index to study temporal and spatial changes in vegetation and its relationship with the climatic index of precipitation in different parts of the world. Studies have shown that NDVI follows precipitation with different time scales. Surveys showed that there are very few studies on determining the threshold of changes in the vegetation cover index in the face of climate shocks. Determining these thresholds can provide a suitable solution for evaluating the state of the ecosystem, the consequences of climate shocks and the reversibility or disturbance in the ecosystem. This study was conducted with the aim of improving our understanding of the dynamics of vegetation in the forest city of Gorgan during 1985-2020 against climatic stresses.   Methodology The current research is a comparative and monitoring research and seeks to test whether changes in vegetation cover are sensitive to climate shocks and also how the ecosystem recovery process is through this index. To achieve the gole, first, NDVI index was selected among the optimal vegetation indices and its calculation process was done as a time series in the GEE system. In parallel with those climate shocks, the main elements including temperature, precipitation and storm were calculated during the historical process of 35 years and the average and standard deviation statistical indicators were calculated for them and the trend of changes in the thresholds was determined. The results of climate plots and climate changes show that in the years before 1985, 2005 and 2020, drastic changes have occurred in climatic elements and climatic factors. Therefore, these years can be considered as the periods when the climate shock happened.. Next, the region was divided into 436 hexagons and the NDVI index for each of the hexagons was calculated and modeled for the years 1985, 2005 and 2020 as selected years affected by climate shocks. In conclusion, to analyze the trend of changes in the time series of the vegetation index and compare the behavior of its changes with climatic indices, the Palmer index was calculated.   Results and discussion The results of climate change monitoring based on the Palmer index showed that during the statistical period the study area is facing drought in most years. The most severe climatic fluctuations and drought in the region were recorded in 2018 and in the months of October to December. The longest period of drought has also prevailed in the region from 2013 to 2020. During this period, rainfall, temperature and storm fluctuations have the most changes. The results of drought monitoring show that in 270 months, the region is facing climatic drought stress, 57 months of the study period, the region is facing severe and very severe drought stress. The results of the time series of the NDVI vegetation index showed that, out of the 420 evaluated months, 70 months of the year the NDVI index is below the change threshold, 31 of which are in the green and non-accumulating seasons, the seasons when the vegetation is expected to be at its maximum. Placing below the acceptable range means crossing the ecological thresholds and challenges the recovery and restoration of the ecosystem, also the ecological performance will be affected at this point. Based on the assessment of the Palmer index, from 2014 to 2019, the situation of the Palmer index is in the extreme drought range. Also, since 2015, i.e. with a one-year time delay, NDVI index has experienced the lower limit of the equilibrium threshold of vegetation cover. These conditions are also valid for the years 2008, 2009, 2002 and 1997. In general, it can be said that the vegetation cover index is dependent on climatic changes and fluctuations and shows high sensitivity to changes. The important point in this section is that in the years when the NDVI index changes are at the lower limit of the threshold, we witness the most climate shocks and temperature changes, the occurrence of severe storms and precipitation fluctuations. The distribution of the vegetation index based on hexagons in 1985 and 2005 have a normal distribution; but in 2020, the graph has deviated from the normal state and skewed towards the vegetation cover index under stress or even thin covers. The visual interpretation done on the vegetation cover index in 1985 confirms the condition of the vegetation cover in the southern and western limits of the region in a state with suitable dense and pasture vegetation and forest cover on the edges. However, in 2005 and 2020, this cover has been changed and mainly turned into agricultural land and poor rangeland. In such a way that in 2020, the situation of the region has revealed the critical state of vegetation. The vegetation cover index in the central areas of the city has also reached from a relatively favorable situation in 1985 to a critical situation with almost no dense and stress-free vegetation cover in 2020. The results of the present studies are consistent with the studies of Visentr Serrano et al. in 2013 and confirm the relationship between NDVI vegetation and climate change. In addition, the results of the studies are consistent with the studies of Alwesabi 2012, Xiai & Moody, 2005 and Yan et al. 2001. In such a way that the present study and the aforementioned studies all confirm the influence of the vegetation index on climate fluctuations and precipitation with a one-year time difference.       Conclusion In general, the threshold is defined as a border with different conditions. After crossing the thresholds, the stability and positioning of the NDVI in the equilibrium range is often difficult, and the ecosystem is constantly spending energy to restore itself or to position itself in a new stability state. The result of the mentioned disorders is the reduction of resilience and resistance in the region, which leads the ecosystem to alternative states or crossing the threshold or being in a new equilibrium state. The results showed that the areas where green vegetation is concentrated and denser are less affected by climatic stresses and show more resilience. However, the areas that have become spots and islands due to destruction in the urban areas are more affected by climatic stress and destruction and show less tolerance against the destruction factors. The results help managers to focus their management plans for the preservation and maintenance of urban green spaces as well as forest and pasture ecotones on the edge of the city by knowing the thresholds.   Funding There is no funding support.   Authors’ Contribution Authors contributed equally to the conceptualization and writing of the article. All of the authors approved thecontent of the manuscript and agreed on all aspects of the work declaration of competing interest none.   Conflict of Interest Authors declared no conflict of interest.   Acknowledgments  We are grateful to all the scientific consultants of this paper.

Introduction: Green roof is one of the options to improve environmental problems of urban areas. Meanwhile there are some worries about the environmental impacts of creating green roofs, as despite the benefits of vegetation, some layers of green roofs like waterproof membrane, are made from polymers. In this survey, environmental impacts of an extensive green roof in its lifetime were compared with a normal roof. Materials and Method: In this survey, life cycle assessment method was used. Since there are various methods to implement a green roof, first different methods of implementation and different materials that can be used in its layers were studied and collected. Then some of these methods were chosen to investigate their environmental impacts in order to find the optimized option to create a green roof. On the next step, life cycle assessment of optimized option and normal roof was conducted. The open LCA software was used to compare environmental impacts of different implementing methods, and also optimized option and normal roof. Results and Discussion: Results showed that the green roof has less environmental impacts than normal roof, during its lifetime. In addition, it was indicated that in some impact categories that the environmental impacts of green roof was more than normal roof the reason was using PVC and geotextile (glass fiber and polyester) in its layers. Results of this paper can be improved by measuring benefits of creating a green roof (such as reducing quantity and quality of run off amounts), and also using materials with less environmental impacts in green roofs layers.

Background and Objective: Increasing population growth and construction of high-rise buildings have doubled the amount of environmental pollution in the cities. Moreover, people use the open urban spaces more than before in order to meet their ecological needs. Accordingly, some parameters such as various vegetation and continuous winds streams can be considerably influential in transmittance of the particle pollution. Therefore, the aim of this research was to study the impacts of different green roofs on the dispersion of pollutants in the standpoint of height and density for urban airflow condition of Shiraz City, Iran.Materials and Methods: In this study, a literature review in the field computer simulation with the help of computational fluid dynamics (CFD) model in Envimet software environment was used.Results: Regarding the importance of using vegetation in the urban spaces, vertical dispersion of the particles in presence of vegetation was explored. By comparing the basic model (without vegetation) results with models including vegetation with short, medium and high crowns, it was revealed that vegetation with medium crowns is the closest model to the basic model with a difference of 7.65 m2/s in terms of vertical dispersion of particles; in fact, it was the most optimized condition for maximizing the dispersion of environmental pollutants.Conclusion: The results showed that the green roofs in the buildings increase the horizontal dispersion of the particulate pollution and decrease this term in the vertical dispersion. Finally, by an expansion of green roof usage in the buildings the sustainability in architecture and urbanism can be achieved.

The unfavorable consequences of the expansion of the metropolitans, including urban heat island and air pollution, have attracted the attention of urban managers to strategies for improving environmental conditions. In recent years, along with population growth and high energy consumption, as well as building materials replacing permeable surfaces and urban green spaces, deteriorate the urban heat island phenomenon and air quality in Tehran. Given the significant area of roof surfaces in urban areas, the application of new and environmentally friendly technologies such as the development of cool and green roofs, with heat island modification impact, can play a positive role in reducing cooling energy consumption and improving air quality. Therefore, to study the mutual interaction between meteorological parameters and changes in the urban structure and its possible side effects on air quality, numerical simulation of green roof and cool roof strategies based on the urbanized coupled meteorological-chemical model (WRF/Chem/SLUCM) during the period June 15 to 30, 2016, have been conducted in Tehran metropolitan area. Results show that the development of cool roofs with an averaged diurnal temperature decrease (-0. 65° C) and a decrease in the heat flux (-57 W/m2) has a positive role in the reduction of Tehran heat island. Also, the relative reduction of atmospheric pollutant concentrations has also been achieved in numerical simulations. It shows that the decrease in the height of the boundary layer and turbulence process as a result of the decrease in near-surface temperature has not caused a significant change in the air quality in Tehran. The development of green roofs has led to a daily (nightly) decrease (increase) in the air temperature. The increase in temperature during the night was noticeable (up to +0. 53° C), and it is a result of the high emissivity of vegetation, as well as a decrease in wind speed in the vicinity of green roof surfaces which slows down the natural ventilation over the city. Furthermore, an increase in the near-surface humidity also predicted in both strategies which improves the environmental comfort satisfaction in the summer hot and dry days. Comparison of these strategies performance shows that cool roof has a significantly sensible cooling effect than green roofs, and the process of reducing pollutants, especially at night, is more favorable in cool roofing strategy. Consequently, since the cooling efficiency of green roofs depends on soil moisture content, as well as comparing construction costs and no need for specific infrastructure, the development of cool roofs in Tehran metropolis is recommended.

Undoubtedly, one of the main and effective members in building structures is the ceiling, and the type of execution of this part of the structure will play a significant role in the speed and quality of the entire structure. The application of old materials and traditional construction methods no longer meets the desired speed and design needs. In this study, in addition to introducing the structure of U-Boot roof, an attempt has been made to provide a comparative approach in terms of structural performance with other common roofs such as steel deck roof, concrete slab and Cobiax roof. For this purpose, after ensuring the results of modeling using Abacus software, modeling of numerical samples and comparing them with other common ceilings have been done. The results indicate that by comparing concrete slabs, when increasing the compressive strength of the specimens, the amount of final yield load is increased, but after the yield point, the failure of the specimens was immediate. Then the load capacity has remained constant for the same displacement, and with a decrease of 30% in the number of U-Boots and a 20% increase in compressive strength, the amount of load capacity has increased by about 22. 32%. Comparing these specimens with the state without reducing the number of U-Boots, it is determined that for each similar sample, the load bearing capacity has increased by 10%. The U-Boot roof also has higher hardness and load-bearing capacity than other roofs and the concrete slab has the lowest loadbearing capacity in the same displacements. The performance of the steel deck roof and the Cobiax roof is also close in terms of bearing capacity, but in terms of the hardness or gradient of the force-displacement curve, the Cobiax roof has shown more hardness.