23 results on '"Ahmad Reza Yavari"'
Search Results
2. An improved method for assessing mismatches between supply and demand in urban regulating ecosystem services: A case study in Tabriz, Iran.
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Vahid Amini Parsa, Esmail Salehi, Ahmad Reza Yavari, and Peter M van Bodegom
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Medicine ,Science - Abstract
Regulating ecosystem services provided by urban forests are of great importance for the quality of life among city dwellers. To reach a maximum contribution to well-being in cities, the urban regulating ecosystem services (URES) must match with the demands in terms of space and time. If we understand the matches or mismatches between the current urban dwellers' desired quality conditions (demand) and the supply of URES by urban forests (UF) in the cities, this will facilitate integrating the concepts of ecosystem services in urban planning and management, but such an assessment has suffered from major knowledge limitations. Since it is complex and problematic to identify the direct demands for URES and the spatiotemporal patterns therein, improving the demand indicators can help to determine the actual requirements. In this paper, a methodological approach based on indicators is presented and demonstrated for two important URES: air quality improvement and global climate change mitigation provided by urban trees and shrubs. Four air quality standards and greenhouse gas reduction targets were used and compared to supplies of the URES in Tabriz, Iran. Our results show that the mean contribution of the URES supply to air quality standards and greenhouse gas reduction targets is modest. Hence, in Tabriz, there is a strong mismatch between demand and supply. Mismatches at the city scale will have to be reduced by both a reduction in pollutant emissions and an increased provisioning of URES supply through urban greenery. The presented assessment approach and the results for Tabriz make it explicit how different the demands and supplies of the two studied URES are, and we expect similar mismatches in many other cities. Therefore, our approach, relatively simple but still realistic and easy-to-apply, can raise awareness about, and the utility of, the ecosystem services concepts for urban planning and policymaking.
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- 2019
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3. Management of socio-ecological wetland systems using mulino decision support system and analytic network process
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Ahmad Nohegar, Ahmad Reza Yavari, Hamidreza Jafari, G. Zare, and Bahram Malekmohammadi
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Decision support system ,geography ,Environmental Engineering ,geography.geographical_feature_category ,Computer science ,business.industry ,Analytic network process ,Environmental resource management ,Wetland ,010501 environmental sciences ,01 natural sciences ,Competition (economics) ,Socio ecological ,Water resources ,Order (exchange) ,Environmental engineering science ,Environmental Chemistry ,General Agricultural and Biological Sciences ,business ,0105 earth and related environmental sciences - Abstract
Wetlands play an important role in the life of the planet. In order to preserve and revive the wetlands, decision-makers need to employ appropriate approaches and tools to identify the main driving forces and this could be an important step toward adopting effective strategies and making critical decisions. The current study used the combined analytic network process with driving forces-pressures-state-impacts-responses framework in mulino decision support system. The Parishan wetland, located in Iran, has been selected as the case study. After an initial study of the conditions of Parishan wetland and identifying the stakeholders, the opinions of experts and local residents were gathered to identify the most important parameters influencing the conditions of the wetland. The analytic network process model was used to improve and reduce the number of input parameters to mulino decision support system. Then, the most important and the best responses associated with the management of Parishan wetland were identified through questionnaires and imported into mulino decision support system along with other components. Finally, the mulino decision support system decision algorithm was run. The findings revealed that reduced precipitation, land-use change, competition of farmers in the wetland to use water resources, and increased temperature were the main driving forces. Moreover, water transfer from the Nargesi Dam was chosen as the most effective response. The results suggest that the driving forces-pressures-state-impacts-responses framework in mulino decision support system algorithm combined with analytic network process model can be used as an integrated tool to study and manage wetland socio-ecological ecosystems.
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- 2021
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4. Spatiotemporal Modelling of Water Balance Components in Response to Climate and Landuse Changes in a Heterogeneous Mountainous Catchment
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Bahram Malekmohammadi, Ahmad Reza Yavari, Mario Schirmer, Negar Tayebzadeh Moghadam, and Karim C. Abbaspour
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Water balance ,Land use ,Soil and Water Assessment Tool ,Evapotranspiration ,Climate change ,Environmental science ,SWAT model ,Precipitation ,Water resource management ,Temporal scales ,Water Science and Technology ,Civil and Structural Engineering - Abstract
Landuse change and climate change are the main drivers of hydrological processes. The purpose of this study was to analyse the separate and combined future effects of climate and landuse changes on water balance components on different spatial and temporal scales using the integrated hydrological Soil and Water Assessment Tool model. The study focused on the changes and relationship between water yield (WYLD) and sediment yield (SYLD) in the heterogeneous Taleghan Catchment in Iran. For future climate scenarios, RCP 4.5 and RCP 8.5 of GFDL-ESM2M GCM were used for 2020–2040. A Markov chain model was used to predict landuse change in the catchment. The results indicated an increase in precipitation and evapotranspiration. The findings also showed that the relationship between WYLD and SYLD is direct and synergic. Climate change has a stronger effect on WYLD than landuse change, whereas landuse change has a stronger effect on SYLD. The conversion of rangelands to barren land is the most critical landuse change that could increase SYLD. The highest increase in WYLD and SYLD in scenario RCP4.5 resulted from the combined effects of climate and landuse change. We estimated WYLD of about 295 mm and SYLD of around 17 t/ha. The proposed methodology is universal and can be applied to similar settings to identify the most vulnerable regions. This can help prioritize management strategies to improve water and soil management in watersheds.
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- 2021
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5. Assessing and Modeling the Impacts of Wetland Land Cover Changes on Water Provision and Habitat Quality Ecosystem Services
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Bahram Malekmohammadi, Leila Rahimi, and Ahmad Reza Yavari
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Sustainable development ,geography ,geography.geographical_feature_category ,Wetland vegetation ,Wetland ,Land cover ,010502 geochemistry & geophysics ,01 natural sciences ,Ecosystem services ,Habitat ,Wetland conservation ,Environmental science ,Water resource management ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
Understanding the spatial–temporal dynamics of wetland land cover (LC) changes and their impacts on ecosystem services (ESs) is essential for wetland conservation and management. This study aimed at quantifying and predicting water provision and habitat quality ecosystem services and analyzing their response to LC changes using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model. Firstly, LC maps were created for 1987, 1998, 2007, and 2017 using the index-based and supervised approach and were then used to predict LC changes for 2027 and 2047 using the cellular automata and Markov chain (CA–Markov) model. The Shadegan wetland, located in the southwest of Iran, was chosen as the case study. The results showed that, during the study period (1987–2017), the LC with major increasing area was bare land while the LC with major decreasing area was wetland vegetation. In addition, the wetland tended to be a fragmented mosaic with less connectivity. The results of ESs modeling showed that the highest and lowest water yield values, which were almost 68 × 106 m3 and 26 × 106 m3, were observed in 1998 and 2017, respectively. In the meantime, the area with high-quality habitats has reduced (by 33.58%) and has gradually been replaced by moderate- and low-quality habitats, and the same trend will continue in 2027 and 2047. Based on these results, we conclude that changes in wetland LCs have resulted in variations of the wetland ESs. This site-specific study of the InVEST water yield and habitat quality models enables us to explore the applicability of spatially explicit modeling and simulating of wetland ESs to improve wetland conservation and management. The findings on the spatial–temporal analysis of wetland LCs and ESs can promote wetlands decision-making processes and taking effective conservation actions.
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- 2020
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6. Landscape conservation and protected areas (case of Dena, Iran)
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Sayedeh Alemohammad, Ahmad-Reza Yavari, Bahram Malek-Mohammadi, Esmail Salehi, and Mohammad-Javad Amiri
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Conservation of Natural Resources ,Anthropogenic Effects ,Humans ,Biodiversity ,General Medicine ,Forests ,Iran ,Management, Monitoring, Policy and Law ,Pollution ,Ecosystem ,Environmental Monitoring ,General Environmental Science - Abstract
Inefficient management of protected areas (PAs) is often due to ignoring their surrounding matrix in the baseline studies, especially in wooded landscapes. In Iran, the application of landscape structure studies in protection policies and PA management is not prevalent. In this study, land cover changes in Dena Rural District (including parts of inside and outside Dena PA) have analyzed using the process of the Landsat images along with field survey two times (1989 and 2018). The landscape structural integrity was quantified based on the situation of oak forest land and its alteration. The composition and the configuration of oak forest land were assessed by metrics based on the moving extent of the Persian squirrel, Sciurus anomalus (which is an endangered focal endemic species completely dependent on the oak forest). Alterations of landscape structural integrity were compared for inside and outside Dena PA and at different altitudes. The results show connectivity loss and increased fragmentation of oak remnant patches, but this deforestation is more severe near areas facing direct human impacts and interventions. These are among attributes that are to be considered for zoning PA (such as controlling zone and training/participation zone). At higher altitudes, physical protection and strict control are more effective, while training local communities for stewardship is more essential at lower altitudes for conserving woodland integrity.
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- 2022
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7. Improving the provision of ecosystem services from urban forest by integrating the species’ potential environmental functions in tree selecting process
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Ahmad Reza Yavari, Vahid Amini Parsa, and Esmail Salehi
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0106 biological sciences ,education.field_of_study ,Ecology ,Range (biology) ,Process (engineering) ,business.industry ,010604 marine biology & hydrobiology ,Population ,Environmental resource management ,Management, Monitoring, Policy and Law ,010603 evolutionary biology ,01 natural sciences ,Ecosystem services ,Tree (data structure) ,Geography ,Urban forest ,Landscape ecology ,education ,business ,Tree species ,Nature and Landscape Conservation - Abstract
Due to the fact that urban environments and population demands are evolving rapidly and species selection is inevitable, it is possible to gain substantial environmental benefit by implementing more effective urban tree planting programs, especially with the aim of increasing the upcoming provision of multiple ecosystem services (ES) through proper species selection. In this paper, we used a new approach to improve the potential of urban trees in optimizing more desirable environmental benefits. This was done by selecting the most appropriate tree species among a vast range of species based on their potential environmental function (both services and disservices) in Tabriz city, Iran. Also, three main planting scenarios (divided to six sub-scenarios) were developed so as to understand the long-term effectiveness of introducing the selected tree species in improving the environmental benefits (both urban forest structure and ES) in comparison with planting the existing tree species. The results indicate that regardless of the quantity of planting, the benefits of introducing the selected trees will be more than planting the existing species. Moreover, as the amount of the annual planting of the recommended species increases, so does the improvement in the projected tree characteristics and ES. This approach creates more opportunities which enable urban forest managers and policymakers to understand the importance of selecting the proper urban tree species when looking for a nature-based solution to promote the wellbeing of the urban population, to create more livable and ecologically sustainable cities and to mitigate urban environmental problems.
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- 2019
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8. Investigating effects of land use and land cover patterns on land surface temperature using landscape metrics in the city of Tehran, Iran
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Ahmad Reza Yavari, Fatemeh Effati, and Hazhir Karimi
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010504 meteorology & atmospheric sciences ,Land surface temperature ,Land use ,Land-use planning ,Land cover ,010502 geochemistry & geophysics ,01 natural sciences ,Standard deviation ,Geography ,Impervious surface ,General Earth and Planetary Sciences ,Physical geography ,Urban heat island ,Zoning ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
Tehran, the capital of Iran, is the most densely populated city in the country that has been experiencing extensive population growth and urban expansion in the last decades. The land use/cover (LULC) patterns have noticeably been changed to impervious surfaces that led to the changes in the thermal condition and forming heat islands in Tehran. In this study, the relationship of LULC patterns with land surface temperature (LST) was investigated using landscape metrics in the city of Tehran. For this aim, the LULC map of the year 2012 was derived from Landsat 7 images. The spectral mixture analysis (SMA) and proximity likelihood algorithm were used to classify the LULC map. Then, the LST zoning map was produced from the thermal sensor band and was classified based on standard deviation and quartile deviation methods. Finally, the landscape metrics applied to analyze the relationship between the LULC patterns and LST zones. The results showed that the LST had a positive correlation with the impervious surface fraction but negatively correlated with the green vegetation fraction. The result also indicated that the temperature decreased with an increase in landscape percent and mean patch size of green spaces. The findings of this study could be useful for urban plans, land use planning, and sustainable development goals programs.
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- 2021
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9. Evaluating the potential contribution of urban ecosystem service to climate change mitigation
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Esmail Salehi, Ahmad Reza Yavari, Vahid Amini Parsa, and Peter M. van Bodegom
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0106 biological sciences ,Ecology ,business.industry ,010604 marine biology & hydrobiology ,Tree planting ,Environmental resource management ,I-tree eco ,Climate change ,Trade-off ,010603 evolutionary biology ,01 natural sciences ,Urban forest ,Ecosystem services ,Urban Studies ,Synergy ,Urban ecology ,Climate change mitigation ,Urban planning ,Greenhouse gas emissions ,Environmental science ,Urban ecosystem ,business ,Carbon storage and sequestration - Abstract
Promoting urban greenery through tree planting strategies has been considered as a measure to mitigate climate change. While it is essential to understand the temporal dynamics of urban forest structure as well as its services and contribution to human wellbeing in cities, it has hardly ever been examined whether the future contributions of these services after different possible planting strategies can comply with climate change policy goals; these are topics rarely discussed in urban planning and management. In this paper, the ecosystem services currently provided by urban trees (through carbon sequestration and storage), as well as those potentially provided in the future, were quantified using the i-Tree Eco model, and their contribution to climate change mitigation was evaluated. As a case study in Tabriz, Iran, we developed four possible scenarios. Synergy (urban temperature regulation by UF) and trade-off (tree water requirements) were also analyzed. Future carbon sequestration and storage potential of urban trees was compared with the estimated future carbon emissions. The current contribution in Tabriz is relatively modest (about 0.2%), but it can be tripled through long-term tree planting strategies. Additionally, the temporal cooling effects and tree water requirements increase as climate change mitigation improves through tree planting. We conclude that urban tree planting has a small impact on carbon mitigation in the study area, most likely because of the young age of trees in Tabriz as well as the fact that the planted trees cannot deliver all their benefits over a 20-years period and need more time. Thus, the use of urban trees serves only as a complementary solution rather than an alternative climate mitigation strategy. Our quantitative approach helps urban environmental policymakers to evaluate how much they can rely on urban forest strategies to achieve climate change mitigation targets.
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- 2019
10. Spatio-temporal analysis of land use/land cover pattern changes in Arasbaran Biosphere Reserve: Iran
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Vahid Amini Parsa, Athare Nejadi, and Ahmad Reza Yavari
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Hydrology ,010504 meteorology & atmospheric sciences ,Land use ,Range (biology) ,Biosphere ,010501 environmental sciences ,01 natural sciences ,Geography ,Deforestation ,Early warning system ,Common spatial pattern ,Ecosystem ,Physical geography ,Computers in Earth Sciences ,Statistics, Probability and Uncertainty ,General Agricultural and Biological Sciences ,Global environmental analysis ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
Main global environment and ecological functions and structure affected by land use/cover changes (LUCC). Analysis of the dynamic LUCC can be very useful in biosphere reserves (BRs) management. The Land use and cover (LULC) spatio-temporal changes in the Arasbaran BR were classified (as Agricultural, Forest and Barren/Range lands), and compared with future spatial pattern (simulated using the CA-Markov model) to evaluate qualitative and quantitative changes of this BR LULC over time (1989, 2000 and 2013 with 2037). This analysis consisted of the whole area and also in respect to each of the zones within the Arasbaran BR (as a new approach to assess BR management quality). Based on this approach, the LUCC monitoring alongside the future simulation offers an early warning system that also shows us trends and consequences of the changes for the whole BR as well as for each zone (including the core zone) of BR separately. The results show a downward trend for forestland at the expense of increasing agricultural and barren/range land surface areas. Furthermore this loss of remnant forest vegetation is not only true for the whole BR (; including its buffer and transitional zones) but is happening within the core zone where it will probably continue more severely in the near future. The results demonstrate the priority need for more severe regulations regarding protection of this BR against LUCCs and for its valuable core zone forest LULC in particular.
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- 2016
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11. Spatio-Temporal Patterns of Wildlife Road Mortality in Golestan National Park-North East of Iran
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Ahmad Reza Yavari, Vahed Dehghani Kazemi, and Hamidreza Jafari
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0106 biological sciences ,biology ,Ecology ,National park ,Vulpes ,Wildlife ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,010601 ecology ,Geography ,Common species ,Wild boar ,biology.animal ,Jackal ,Canis aureus ,Marten - Abstract
Nowadays, wildlife road mortality is acknowledged as a main source of threatening long-term survival of wildlife. This paper as the first to analysis wild life vehicle collisions in Iran, aims to reconstruct and interpret the spatio-temporal patterns of WVCs on Asiaei highway in Golestan National Park (GNP). With the collaboration of environmental protection department of GNP, we identified about 1900 WVC Records involving 34 different species of mammals, birds, reptiles and amphibians between 2004 and 2013. Mammals were involved in more than 50% of overall WVCs, among which wild boar (Sus scrofa), Golden Jackal (Canis aureus), Red Fox (Vulpes vulpes), hedgehog (Erinaceus concolor), stone marten (Martes foina) and porcupine (Hystrix indica) were involved in more than 90% of mammals’ mortalities; So, we focused on analyzing spatio-temporal pattern of vehicle collisions of these six mammal species. During the study period, these species have undergone 95% increase in road mortalities, averagely. Detailed temporal analyses exhibited an increasing trend of road mortalities from spring to summer and then a reducing one to late winter. It was shown that a large number of collisions occurred in holiday periods when recreational trips considerably increased the traffic volume of Asiaei highway. Preliminary inspection of spatial patterns using Kernel density analysis revealed six collision hotspots, mostly located in the road bends with densely forested land cover on both sides; the promenades along the road seemed to play a significant role too. Scale dependency analyses of collision patterns, demonstrated clustering pattern at micro scales less than 10 km, randomness at meso scales 10 - 20 km and both regularity and clustering at macro scales more than 20 km. This paper suggests that road mortality of common species in GNP is a momentous issue, which needs to be considered by relevant governmental and public organizations. We also emphasize that the analyses of spatial and temporal patterns of WVCs are fundamentals to plan for mitigate wildlife road mortality.
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- 2016
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12. Habitat Suitability & Connectivity of Alborz Wild Sheep in the East of Tehran, Iran
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Afshin Alizadeh Shabani, Zeinab Yeganeh Keya, Yahya Kamali, S H Faryadi, and Ahmad Reza Yavari
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0106 biological sciences ,Ecology ,010604 marine biology & hydrobiology ,Species distribution ,Metapopulation ,010603 evolutionary biology ,01 natural sciences ,Geography ,Habitat destruction ,Habitat ,Threatened species ,IUCN Red List ,Biological dispersal ,Protected area - Abstract
Habitat loss and fragmentation of the wildlife species due to anthropogenic developments have been becoming serious issues in biological conservation. Alborz wild sheep, listed as threatened by IUCN, is distributed in relatively small and isolated patches in an increasingly human dominated landscape in the north-central Iran and east of Tehran. We used maximum entropy modeling to identify habitat areas of the wild sheep, across Jajrud protected area and its neighbouring protected areas including varjin, lar, koohsefid and the surroundings. Regarding to seasonal variation of the species home range, winter, summer and multi seasonal (annual) habitats were predicted. To estimate habitat connectivity, we used models of connectivity based in electrical circuit theory. Applying core areas of multi season for connectivity analysis, movement pattern of the species was predicted and important connective areas for conservation were identified. Species distribution maps revealed that the summer and winter habitats were approximately occurred in similar areas. Distance to eco-guards’ post was the most important predictor for both habitat models of summer and winter. The annual model, which is a combination of summer and winter, shows that the largest suitable habitat patches are located in the north, south and west of the study area. Maximum current flow map demonstrates that the areas among patch pairs are covered in low current, reflecting low rates of the species dispersal. This map presented bottlenecks to the species movement across major roads and along extending human settlements. Cumulative current flow map displayed that current was highest in Jajrud north of Mamloo extending to the northern Jajrud. Overall, our study demonstrated a prediction of habitat suitability and connectivity for Alborz wild sheep in east of Tehran, which can be used to direct conservation endeavours dealing with maintenance of the wild sheep metapopulation dynamics.
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- 2016
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13. Analyzing temporal changes in urban forest structure and the effect on air quality improvement
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Vahid Amini Parsa, Ahmad Reza Yavari, Esmail Salehi, and Peter M. van Bodegom
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Tree planting ,media_common.quotation_subject ,Geography, Planning and Development ,0211 other engineering and technologies ,Air pollution ,Transportation ,02 engineering and technology ,010501 environmental sciences ,medicine.disease_cause ,01 natural sciences ,Ecosystem services ,Urban forest ,medicine ,Quality (business) ,021108 energy ,Air quality index ,0105 earth and related environmental sciences ,Civil and Structural Engineering ,media_common ,Structure (mathematical logic) ,Renewable Energy, Sustainability and the Environment ,business.industry ,Environmental resource management ,Environmental science ,Green infrastructure ,business - Abstract
Tree planting practices are being increasingly advocated as measures to improve the air and living quality in urban landscapes around the world. Nevertheless, there is still a lack of quantitative understanding of the effects of the increases in tree cover on the future potential of urban forests when it comes to air quality improvement. Therefore, this research aims to assess and quantify the current and future biophysical and monetary value of the regulating ecosystem service provided by urban forest in Tabriz, Iran (as a case study). Both the current conditions and future prospect are assessed through tree planting scenarios based on the i-tree Eco model. The results indicate that the trees and shrubs removed 238.4 t of pollutants during a year (in 2015), which suggests only a modest potential in air purification when compared with other cities around the world. However, through appropriate – though feasible – urban forest management and development practices, they may improve up to 814.46 t cumulatively over the next 20 years. Tree planting schemes have different efficacies in terms of providing air purification services. Our data-rich temporal approach allowed identifying the optimum tree planting strategy, taking into account the growth and mortality dynamics. Thus, the paper illustrates a methodology to assess the current and future potentials of urban forests to reduce air pollution at the city-scale, which helps the development of future urban tree planting strategies in cities to improve air quality as well as the management of the green infrastructure. Our approach paves the way for the quantitative assessment and optimization of the future condition of (urban) ecosystem services.
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- 2019
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14. Methodology for modeling of city sustainable development based on fuzzy logic: a practical case
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Mad Nasir Shamsudin, Zelina Zaiton Ibrahim, Fereshteh Jaderi, Seyed Mohammad Bagher Nabavi, Neamat Jaafarzadeh, Ahmad Reza Yavari, and Ramdzani Abdullah
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Sustainable development ,Engineering ,Measure (data warehouse) ,Renewable Energy, Sustainability and the Environment ,business.industry ,Management science ,media_common.quotation_subject ,Public Health, Environmental and Occupational Health ,Urban sustainability ,Environmental economics ,Fuzzy logic ,Adaptability ,Environmental Sustainability Index ,Sustainability ,business ,computer ,Delphi ,General Environmental Science ,computer.programming_language ,media_common - Abstract
Information on sustainability can be used for future development planning. This study presents an approach for assessing urban sustainability. Delphi and fuzzy logic methods and the Kruskal–Wallis test were the discovery and verification techniques used. The city system comprised social, economic, and environmental subsystems. The seven orientors of existence, effectiveness, freedom of action, security, adaptability, coexistence, and psychological need were measured using different indicators. The final sustainability output was obtained by aggregation of the multiple orientors and subsystems sustainability values into a unified measure. A fuzzy sustainability index was developed to compare the importance of the sustainability orientors and subsystems. The model was applied to Mahshahr, an industrialized coastal city in Iran. The model output for the subsystems showed significant differences between the economic and environmental subsystems and the social subsystem. The final sustainability output showed ...
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- 2014
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15. Investigating the causality of changes in the landscape pattern of Lake Urmia basin, Iran using remote sensing and time series analysis
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Majid Ramezani Mehrian, Raul Ponce Hernandez, S H Faryadi, Esmaeil Salehi, and Ahmad Reza Yavari
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Salinity ,Agricultural Irrigation ,010504 meteorology & atmospheric sciences ,Climate ,Iran ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,Structural basin ,01 natural sciences ,Time series ,0105 earth and related environmental sciences ,General Environmental Science ,Remote sensing ,business.industry ,Temperature ,General Medicine ,Hypersaline lake ,Pollution ,Water level ,Water resources ,Lakes ,Trend analysis ,Agriculture ,Remote Sensing Technology ,Threatened species ,Environmental science ,business - Abstract
Lake Urmia is the second largest hypersaline lake in the world in terms of surface area. In recent decades, the drop in water level of the lake has been one of the most important environmental issues in Iran. At present, the entire basin is threatened due to abrupt decline of the lake's water level and the consequent increase in salinity. Despite the numerous studies, there is still an ambiguity about the main cause of this environmental crisis. This paper is an attempt to detect the changes in the landscape structure of the main elements of the whole basin using remote sensing techniques and analyze the results against climate data with time series analysis for the purpose of achieving a more clarified illustration of processes and trends. Trend analysis of the different affecting factors indicates that the main cause of the drastic dry out of the lake is the huge expansion of irrigated agriculture in the basin between 1999 and 2014. The climatological parameters including precipitation and temperature cannot be the main reasons for reduced water level in the lake. The results show how the increase in irrigated agricultural area without considering the water resources limits can lead to a regional disaster. The approach used in this study can be a useful tool to monitor and assess the causality of environmental disaster.
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- 2016
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16. Reduction of environmental pollution through optimization of energy use in cement industries
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Hamid Jafari, H. Sid Kalal, Ahmad Reza Yavari, Hassan Hoveidi, and Abdolreza Karbassi
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Engineering ,Environmental Engineering ,Waste management ,Power station ,business.industry ,Environmental engineering ,Environmental pollution ,Fuel oil ,Energy consumption ,Clean Development Mechanism ,Fuel gas ,Greenhouse gas ,Roller mill ,Environmental Chemistry ,General Agricultural and Biological Sciences ,business - Abstract
Industrial development has lead to higher energy consumption, emission of greenhouse gases, as well as air pollutants. Cement factories play an important role in over all greenhouse emissions. This study aims to investigate the role of Iranian cement industries and their contribution of greenhouse gases contribution. The measured emission factors for oil and fuel gas shows that carbon dioxide contribution from fuel oil based cement industries is almost 2.7 times higher than gas based cement factories. The strength, weakness, opportunity and threat technique analysis showed that the best strategy to combat greenhouse gases from Iranian cement factory is to implement energy efficiency measures. Further, strategic position and action evaluation matrix analysis indicates that Iranian cement industries fall within invasive category. Therefore, exploitation of opportunities must carefully be used. One of these opportunities is the utilization of financial assistance provided by clean development mechanism. The results show that replacement of ball mills with vertical roller mill can reduce the electricity consumption from 44.6 to 28 kWh/ton. As a result of such substitution about 720 million kWh/y of electricity would be saved (almost a power plant of 125 MW capacities). Though implementation of new mills may not be economic for the cement industries' owner, but the overall gain for the government of Iran will be about US$ 304 million. If the duration of such efficiency measure is considered as about 12 y, then the overall CO 2 reduction/phase-out would be around 4.3 million tons.
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- 2009
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17. Effect of transesterification products on the miscibility and phase behavior of poly(trimethylene terephthalate)/bisphenol A polycarbonate blends
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Ahmad Reza Yavari, Seyed Hassan Jafari, R. Hässler, Ahmad Asadinezhad, Hossein Ali Khonakdar, and Frank Böhme
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Bisphenol A ,Materials science ,Polymers and Plastics ,Organic Chemistry ,General Physics and Astronomy ,Transesterification ,Miscibility ,law.invention ,chemistry.chemical_compound ,Crystallinity ,chemistry ,Chemical engineering ,Extent of reaction ,law ,visual_art ,Polymer chemistry ,Materials Chemistry ,visual_art.visual_art_medium ,Copolymer ,Polycarbonate ,Crystallization - Abstract
Blends of poly(trimethylene terephthalate)/bisphenol A polycarbonate (PTT/PC) with different compositions were prepared by melt blending. The effect of transesterification on the miscibility and phase behavior of the blends was studied using DSC, DMA, and 1 H NMR. The DMA results revealed a two-phase system with partial miscibility. DSC thermograms of the first heating scan showed a crystallizable system in which addition of PC-phase reduces the degree of crystallinity. However, the cooling and also the second heating scans revealed the complete miscibility of all the blends. It was concluded that annealing at 300 °C (to remove thermal history of the blends) caused the constituents to undergo the transesterification reaction, which changes the blend to a miscible system. The miscibility is due to formation of block copolymers with different block lengths which also suppress the crystallization of the system. The degree of randomness and sequence lengths of the copolymers were determined to analyze the extent of transesterification reaction and structure of the system. It was observed that as the reaction progresses, the degree of randomness increases and the sequence length of the copolymers decreases. Moreover, both increase of reaction time and temperature increased the extent of reaction. The results of DSC and 1 H NMR showed that a small amount of reaction is needed to change this system to a miscible blend.
- Published
- 2005
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18. Correlation of morphology and rheological response of interfacially modified PTT/m-LLDPE blends with varying extent of modification
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Seyed Hassan Jafari, Ahmad Reza Yavari, Ahmad Asadinezhad, Hossein Ali Khonakdar, and Frank Böhme
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Materials science ,Polymers and Plastics ,Rheometry ,Organic Chemistry ,Compatibilization ,Shear modulus ,Linear low-density polyethylene ,chemistry.chemical_compound ,chemistry ,Rheology ,Phase (matter) ,Materials Chemistry ,Polymer blend ,Composite material ,Saturation (chemistry) - Abstract
Morphology and rheology of poly(trimethylene terephthalate)/metallocene linear low-density polyethylene (PTT/m-LLDPE) immiscible blends with varying extent of compatibilization were experimentally examined and theoretically analyzed using Palierne and Coran models. A glycidyl methacrylate-based terpolymer was used to modify the interface of the blend. The particle radius in the PTT75/m-LLDPE25 system decreases in proportion to the level of added compatibilizer up to 5 wt% of terpolymer, beyond which the particle size remains unchanged. This is attributed to the saturation of interface by interfacial modifier leading to diminish the effectiveness of the compatibilizer. Morphological observations reveal that the saturation of the interface for PTT25/m-LLDPE75 system occurs at 2.5 wt% compatibilizer content. Rheological examinations show a sharp reduction of complex viscosity for the latter system at 10 wt% terpolymer which is ascribed to the micelle formation in the bulk phase. Plots of the relaxation time spectrum exhibit that upon addition of the compatibilizer the magnitude of the relaxation peaks associated with interface increases which is ascribed to the increase of the interfacial area. The Palierne model fails to predict admissible values and reasonable trend for interfacial tension. This failure is believed to be due to the excessively large difference between the complex shear modulus values of the dispersed and matrix phases. However, the Coran model used to describe the dynamic moduli, shows a good fit to the experimental data.
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- 2005
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19. Rheology, Morphology and Estimation of Interfacial Tension of LDPE/EVA and HDPE/EVA Blends
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Seyed Hassan Jafari, Ahmad Asadinezhad, Hossein Ali Khonakdar, Udo Wagenknecht, and Ahmad Reza Yavari
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Materials science ,Polymers and Plastics ,Ethylene-vinyl acetate ,General Chemistry ,Dynamic mechanical analysis ,Polyethylene ,Condensed Matter Physics ,chemistry.chemical_compound ,Low-density polyethylene ,Viscosity ,chemistry ,Rheology ,Materials Chemistry ,High-density polyethylene ,Polymer blend ,Composite material - Abstract
Rheological characteristics and morphology of low-density polyethylene (LDPE) /ethylene vinyl acetate copolymer (EVA) and high-density polyethylene (HDPE)/EVA blends were compared. Morphological examinations clearly reveal a two-phase morphology in which the LDPE/EVA blends have smaller dispersed domain size than HDPE/EVA Furthermore, LDPE/EVA shows a finely interconnected morphology at 50wt% of EVA while HDPE/EVA exhibits a coarse co-continuous morphology at the same composition. The morphological observations can be attributed to the lower viscosity ratio and lower interfacial tension in the LDPE/EVA system. The Palierne model also successfully fits to the experimental data giving higher values for interfacial tension of HDPE/EVA system as compared to LDPE/EVA.
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- 2005
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20. Description of the dynamic moduli of poly(trimethylene terephthalate)/polyamide-12 blends in molten state
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Ahmad Asadinezhad, Ahmad Reza Yavari, Seyed Hassan Jafari, Hossein Ali Khonakdar, and Frank Böhme
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Viscosity ,Materials science ,Polymers and Plastics ,Rheology ,Rheometer ,Plastics extrusion ,Polyamide ,Materials Chemistry ,General Chemistry ,Polymer blend ,Dynamic mechanical analysis ,Composite material ,Viscoelasticity - Abstract
Binary melt blends of two thermoplastics—poly(trimethylene terephthalate) (PTT) and polyamide-12 (PA12)—having a large difference in zero-shear viscosity values, were prepared in different blending ratios (PTT/PA12 90/10, 75/25, 25/75, 10/90) by means of a twin-screw extruder. Scanning electron microscopy (SEM) confirmed droplet morphology subsequently quantified using image analysis. Dynamic rheological behavior at blending temperature (230°C) was also recorded on a parallel plate oscillatory rheometer within the linear viscoelastic range. The applicability of two emulsion models, the Palierne analysis plus the Gramespacher and Meissner model, as well as a micromechanical model, the Coran analysis, to describe the dynamic moduli of the system in different compositions was investigated and also a comparison on these models was presented. POLYM. ENG. SCI., 45:1401–1407, 2005. © 2005 Society of Plastics Engineers
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- 2005
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21. Environmental Impact Assessment of Petrochemical Industry using Fuzzy Rapid Impact Assessment Matrix
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Ahmad Reza Yavari, Gholamreza Nabi Bidhendi, Morteza Ghobadi, and Hamid Jafari
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Decision support system ,Petrochemical ,Municipal solid waste ,Impact assessment ,business.industry ,Fuzzy model ,Control (management) ,Environmental science ,Environmental impact assessment ,Environmental economics ,business ,Fuzzy logic ,Biotechnology - Abstract
Due to the high potential of petrochemical industry in the creation of environmental impact, environment impact assessment of the development of petrochemical industry is very important. The aim of this study is to provide and test a fuzzy model for environmental impact assessment of petrochemical industries as a decision support system in planning process and the development of petrochemical industry. To test this model, the Lorestan province was chosen as the study area. In order to assess the impact of petrochemical industry in Lorestan, the combination of RIAM method and fuzzy theory was used. First, using check lists and holding meetings with experts, the type of petrochemical industry impacts on environmental factors was determined. Next, the effects of project activities on environmental factors were scored; the fuzzy scoring was done using defined criteria in MATLAB software. Environmental components considered in the method used were divided into 4 main factors including physicalchemical, biological-ecological, social-cultural and economic-functional and 33 sub-factors, assessment of nonimplementation, construction and operation stage was carried out individually. The results show the most important environmental impacts of petrochemical projects, water and soil pollution, air and noise as well as its socioeconomic consequences. The results showed that the operation in petrochemical industry will create more important implications than the construction stage, some of them in terms of lack of control and environmental management, are irreversible and damaging.
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- 2015
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22. Evaluating citizen attitudes and participation in solid waste management in Tehran, Iran
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Touraj, Nasrabadi, Hassan, Hoveidi, Gholamreza Nabi, Bidhendi, Ahmad Reza, Yavari, and Shahin, Mohammadnejad
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Community Participation ,Iran ,Refuse Disposal - Abstract
Recently, increasing attention has been paid to the environmental impact of solid waste in Iran. Consequently, solid waste management has become a remarkably important issue. Solid waste comprises a wide range of materials and comes from a variety of sources. Having a population of about 10 million (about 1/7 of Iran's total population), Tehran is among the most populated capitals in the world. With 22 different districts, this city generates approximately 7,000 metric tons of municipal waste per day that culminates in a total of 2.5 million tons annually. If no reduction strategy on the waste stream is implemented, this huge amount of waste will be buried in Kahrizak (the exclusive landfill site of Tehran). Land and underground water resource degradation in the vicinity of the landfill site-as well as disease outbreaks in the area surrounding the site may be considered alarming warnings for further catastrophic consequences of uncontrolled waste dumping. In this study, the composition of Tehran's solid wastes is analyzed. In order to physically analyze waste generated, waste sampling was carried out by trained workers of the Tehran organization of waste recycling and compost in 2004 for 10 successive days in the middle of each of four seasons. As a result of the study, some practical recommendations are made to reduce the waste stream load directed toward the land. Furthermore, this study evaluated people's concern about the fate of the waste they generate. According to the data collected in a survey, citizens' participation is not remarkably high, but even the modest cooperation recorded may cause a great benefit if extrapolated to the whole city. By virtue of sharp decreases in the cost of total waste collection and transport, as well as the benefits of land and underground water resource preservation, separation of wastes at their source by individual households makes economic sense.
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- 2009
23. Prediction of Temperature and Precipitation in Damavand Catchment in Iran by Using LARS –WG in Future
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Mohamad Hosein Niksokhan, Saeed Karimi, Ahmad Reza Yavari, and Sepideh Karimi
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Water resources ,geography ,geography.geographical_feature_category ,Coefficient of determination ,Meteorology ,Climatology ,Drainage basin ,Climate change ,Precipitation ,Performance indicator ,Downscaling ,HadCM3 - Abstract
In recent years the issue of climate change and its effects on various aspects of the environment has become one of the challenges facing planners. It is desirable to analyze and predict the change of critical climatic variables, such as temperature and precipitation, which will provide valuable reference results for future water resources planning and management in the region. The aims of this study are to test the applicability of the Long Ashton Research Station Weather Generator (LARS-WG) model in downscaling daily precipitation and daily maximum (Tmax) and daily minimum (Tmin) temperatures in Damavand catchment in Iran and use it to predict future changes of precipitation and temperature. Future climate of the Damavand catchment is predicted by statistical downscaling outputs from General Circulation Models (GCMs) (HADCM3 for SRES A2 and B2 and A1B scenarios) for the period of 2046–2065.The results showed that the LARS-WG model produces excellent performance in downscaling Tmax and Tmin in the study region but compared to temperature, the model showed more error in downscaling daily precipitation. This issue was confirmed by examining the performance indicators including coefficient of determination, mean absolute error and root-mean square error. Also results showed that precipitation will decrease in future under these scenarios but temperature will increase. Findings of this study will serve as a reference for further studies and planning of future water management strategies in the Damavand catchment.
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- 2015
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