Sharif Digital Repository

About 6.5 million people die from air pollution annually, of which 5.5 million are from the Asian continent. By considering reduction of life span and external costs associated with the emission of air pollutants, the importance of environmental impact assessment and managing the reduction of pollutant emissions becomes even more important. Meanwhile, the largest share (85%) of pollutant emissions is related to the supply and demand sectors of energy carriers. Therefore, the design and development of the environmental impact assessment system of energy flows is a necessity in the process of sustainable development of the energy sector.A key policy challenge in Tehran megacity is to curb high... 

The aim of conducting this research is to study, fabrication and photocatalytic application of electrospun ZnO-based composite nanofibers. One of the most important challenges is to apply photocatalyst under solar irradiation and improve its activity for pollutant degradation. ZnO is a wide band gap semiconductor, hence, it is not active under the visible light. In Iran, we have at least 300 sunny days in a year. Therefore, fabrication and application of photocatalytic material with activity under the sunlight which contains 47% of visible light is so vital in our country. Since CuO is a visible light active photocatalyst and its interface with ZnO forms a type I heterojunction, this... 

Noise or noise pollution, is defined as an unwanted sound, produced mostly by motor vehicles in urban areas. If the noise exceeds its limit, adverse effects on users and citizens are expected. Thus the assessment of the noise level and its comparison with allowable values is mandatory. Traffic induced noise depends upon different factors such as traffic, weather, and, sound barriers. Noise pollution study has a long history all over the world. Many studies, mostly representing the outdoor noise pollution models, have been done in recent years. This paper presents an assessment of traffic-induced noise in a heavily traveled tunnel, locally referred to as Resalat tunnel, which is located in... 

Millions of people are exposed to noise every day in their work and life, and their physical and mental health is at risk due to this issue. Hence, the issue of noise and vibration has become an important factor in car quality. One of the sources of noise and vibration in the vehicle is the engine. The engine is the heart of the car and its most important part. Therefore, reducing Engine noise can have a significant effect on the noise emitted by the vehicle. Engine noise can be divided into three categories: 1 - combustion noise 2 - mechanical noise 3 - aerodynamic noise. This project is in line with a project defined between the university and industry aimed at improving all sources of... 

The silencer is used to reduce sound in the vehicle, air conditioning channels, power plants and guns. Functional parameters of the sound amplifier are the amount of noise reduction and pressure drop. There are few studies on the flow and pressure distribution in the silencer, and there is no article about the effect of the size of the internal passages on the pressure drop and acoustical performance of the silencer. Few studies have been done on the effect of the absorbent fiber diameter on the acoustic performance of silencer. In this study, the effect of different shapes of internal channels (extended tubes, baffles and number of chambers) on the pressure drop and acoustic performance of... 

Considering the increase of particulate matters in the last three decades in Tehran, many endeavores have been made in order to determine and recognize the contributing factors in the production of particulate matters. Although emission source of particulate matters is available in the form of emission inventories, these emission sources are not accurate and they need to be modified. By modeling the air pollution we can determine the relationship of pollution source and their effect on air quality.Modeling air pollution helps us to determine the relationship of pollution sources and their effect on air quality. Air pollution managers use models to determine the contribution of emission... 

Particuale matters, as a criterion for evaluationg the air quality, have been one of the most important air pollutants through the last decade. Considering the adverse health effects of particulate matters, the importance of monitoring pollutant’s concentration is inevitable. While there are monitoring stations for evaluating the air quality, our knowledge is so limtted since there are few stations working, so there is a spatial and temporal gap. On the other hand, chemical transport models and remote sensing provide us a better chance to track the air quality thoroughly. Since chemical transport models are our only way of filling the gaps, they should be rigorous and accurate. In this study... 

The main aim of present thesis is to synthesis and characterize of ferrite nanocomposites as a new generation phtocalyst and their application in degradation of various types of environmental pollutants in different irradiation time and dark conditions. Ferrites have been used anchored to carbon allotropes such as graphene oxide and carbon nanotubes, in order to improve their photocalytic activity as well as phase structure, textural and optical properties. Firstly, a new SnS2-BiFeO3/rGO nanocomposite has been prepared to increase the visible-light-responsive photodegradation of organic dyes such as cationic methylene blue (MB) and anionic methyl orange (MO). The obtained results showed... 

By increasing of population, migration to urban area and industrial development, the concern of environmental pollution becomes more important. Wastewaters are one of the polluting agents which should be collected, treated and reused in a safe and healthy condition. Generally wastewater treatment systems are classified into two major groups, namely aerobic and anaerobic treatment systems.Anaerobic fixed bed reactors are used for decreasing the organic load of wastewater. Enhancement of microbial retention time by attaching the organisms to packings is the most significant advantage of this bioreactor which increases the removal efficiency of organic materials of strength wastewater.In this... 

In this projekt, nanophotocatalysts containing metal oxides and oxy-acids based on the nanoporous materials were synthesized. The photocatalytic properties of the prepared samples were evaluated by the photodegradation of day moleculs in photocatalytic systems. The catalytic results revealed that Ag3VO4/Cu-MOF/rGO exhibits noticeably an improvement in both efficiency and rate of AB92 photodegradation in comparison with the pure Ag3VO4. Using different scanning mechanisms for the catalytic properties of the synthesized nanocomposites, it was clearly demonstrated that the anionic superoxide plays a decisive role. Reduction of 4-NP in the presence of NaBH4 was also used to investigate... 

Different nanocomposites were prepared based on the carbon nitride, structures and metal organic framework. The photocatalytic activities of a group of metal-organic metal frameworks were evaluted. Next step, the combination of binary and ternary composites based on carbon nitride/metal-organic frameworks structures with other semiconductors such as oxyacid, bismuth oxy halide and ferrite spinel was used. In addition, synthesis of varius type of metal oxides structures with metal organic framework precursors has also been another perpuse of this thesis.The catalytic and photocatalytic activities of designed nanocomposites were performed for a redox process (4-nitrophenol (4-Nip) to... 

Carbon dioxide emissions account for 80% of current greenhouse gas emissions that contribute to global warming; this majority stake held by carbon dioxide indicates that reduction in its release to the atmosphere and capturing emissions accomplished is imperative in conservation of human life in earth. The aim of this project is CO2 capturing from ambient air to decrease air pollution with uses building surface that is wide available surface, as basis of adsorbent. In this research, we select CaO as absorbent that it is proven good absorbent in high temperature for CO2. We studied this absorbent in low temperature and pressure. We experimented different weight amount of sorbent 2,3,4,5,6.5... 

Vehicular tunnels are very prone to excess of air pollution due to their enclosed nature. Inadequate ventilation combined with high traffic flow result in elevated concentration of vehicle-induced air pollutants, which can pose serious health hazards. This study was carried out in the longest vehicular tunnel in Tehran, locally referred to as Tohid tunnel. Traffic flow characteristics, carbon monoxide level and it's dispersion along the tunnel were investigated in this project. Data were collected in 4 days and 3 times a day, 7-8 in the morning, 11-12 and 17-18 in the evening. Measurements were conducted at fixed locations, outside the tunnel,... 

The concentration of air pollutants in the environment is variable according to different factors, including distances from main sources. Vehicles in streets and highways are one of the most important sources of the air pollutants. Hemmat highway is one of the most significant highways in Tehran with traffic congestion of 15000 to 18000 vehicle/hour. In this research, the concentrations of PM10 and CO were determined in different distances of Shahid Hemmat highway and the relationship diagrams of traffic and meteorology to the amount and emission of air pollutants were drawn. The concentration gradient diagrams showed exponential decay, which demonstrated that more than of 50% of air... 

Importance of consumption of energy and extraction of energy from its reserve in all over the world and whole industries lies in the fact that availability of fossil fuels is limited and demand of it in industries is huge. For the sake of life of industries, each industry sector should be expanded quantitatively, so growth of energy consumption is inevitable. Development of cement industry is effected in total energy demand and harmful pollutants in whole the country and limitation in energy supply and low level of reliability in energy supply cause the increase of cement production cost which will be effected negatively in relativity principle of prioritization in cement export due to... 

Many studies on hybrid vehicles have been done in the past few years. The Full hybrid vehicles need a large number of batteries creating up to 300V to meet the required voltage of electric motor. The size and weight of the batteries cause some problems. This research investigates the mild hybrid vehicle. This vehicle includes a small electric motor and a high power internal combustion engine. In most cases the car’s driving force is created by internal combustion part. A small electric motor, which can operate as engine starter, generator and traction motor, is located between the engine and automatically shifted multi-gear transmission (gearbox). The clutch is used to disconnect the gearbox... 

Polyagent photocatalysts based on the zeolite including TiO2, Ag and AgBr prepared by Sol-gel method. Ag and AgBr prevent of electron-hole recombination and enhance photocatalytic activity. Prepared catalysts were characterized by different analysis method including XRD, SEM, EDX, FTIR and BET techniques. Catalyst activities were investigated from two aspects: in first step the activities of catalyst were investigated for degradation of AB92 dye. The effect of different factors such as: catalyst concentration, dye concentration, pH and scavenger (sodium thiosulphate) on efficiency and reaction rate were investigated. The optimazed values for all conditions specified, then catalyst activities... 

Oil and gas upstream, is one of the major parts of the energy chain in the world. Processes of production, transportation, processing and conversion of energy carriers are the main parts of this sector. Process units of oil and gas upstream industry are some of most local and global pollution resources in the world. In this research, the consideration of the pollutions from the production, processing and conversion of fossil fuels sector and the optimization of the management choices of each pollutant is subjected. Consideration of the pollutants related to the upstream sector, pollution control and management choices, cost accounting of the environmental impacts, the methods of accounting... 

Chlorinated hydrocarbons such as trichloroethylene form a kind of dense non-aqueous phase liquid contaminants in groundwater and soil that are so difficult to remediate. In recent years, many field research has been demonstrated application of nano scale zero valent iron can degrade these contaminants.
In this research, nZVI particle synthesized by liquid phase reduction method. Nickel (25%wt ) has been added to increase the reduction rate and also reduce intermediate pollutions. However, the combination of a noble metal to nZVI, leads to more rapid oxidation and tendency to agglomeration. So nZVI particles coated by applying a water soluble-starch solution (0.4%wt) as a stabilizer. The... 

The oilfields' wastewater, the water that is produced beside oil and is called ''Produced Water'', includes a large variety of pollutants. Heavy metals such as Lead, Manganese, Zinc and Barium and their compounds are some of the produced water's pollutants and because of their high stability they accumulate in life cycle. So a suitable and proper treatment is necessary. A combination of effectual and important parameters such as good adsorption, magnetic properties and low prices made Iron nanoparticles have a bright future in management of environmental pollutions. In this study Maghemite and Magnetite nanoparticles are used to remove heavy metals and effect of others factors such as pH,...