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Chemical speciation of pm2.5 in tehran: quantification of dust contribution and model validation
, Article Atmospheric Pollution Research ; Volume 11, Issue 10 , 2020 , Pages 1839-1846 ; Lai, A. M ; de Foy, B ; Schauer, J. J ; Arhami, M ; Hosseini, V ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Each year, considerable levels of dust particles coming from arid regions of the earth contribute to the atmosphere. Because dust has serious environmental and human health effects, predictions of dust concentrations and their contribution to PM surface concentrations are essential for atmospheric research and the implementation of air quality programs and rules. This study aims to assess dust contributions to PM2.5 in Tehran in order to provide guidance for air quality management systems as well as validate the updated Dust Regional Atmospheric Model version 2 (BSC-DREAM8b) and the NMMB/BSC-Dust model using chemical speciation of ground-based measurements of PM2.5. Accurate and reliable...
Applications of single-layered graphene sheets as mass sensors and atomistic dust detectors
, Article ASME International Mechanical Engineering Congress and Exposition, IMECE 2007, Seattle, WA, 11 November 2007 through 15 November 2007 ; Volume 11 PART A , 2008 , Pages 99-104 ; 079184305X (ISBN); 9780791843055 (ISBN) ; Ahmadian, M. T ; Vafai, A ; Sharif University of Technology
2008
Abstract
Molecular structural mechanics is implemented to model vibrational behavior of defect free single-layered graphene sheets (SLGSs) at constant temperature. To mimic these two-dimensional layers, zigzag and armchair models with cantilever and bridge boundary conditions are adopted. Fundamental frequencies of these nano structures are calculated, and it is perceived that they are independent of the chirality and aspect ratio. Effects of point mass and atomistic dust on the fundamental frequencies are also considered in order to investigate the possibility of using SLGSs as sensors. Results of exhibit the principle frequencies are highly sensitive to the added mass in the order of 10-6fg....
Design and Implementation of Electrical Dust Control System Using DSP Processors
, M.Sc. Thesis Sharif University of Technology ; Vosoughi Vahdat, Bijan (Supervisor) ; Hashemi, Matin (Co-Advisor)Investigation of adding cement kiln dust (CKD) in ordinary and lightweight concrete
, Article Advances in Concrete Construction ; Volume 5, Issue 2 , 2017 , Pages 101-115 ; 22875301 (ISSN) ; Zolfaghary, S ; Jafari, N ; Dehestani, M ; Hejazi, M ; Sharif University of Technology
Techno Press
2017
Abstract
Cement kiln dust (CKD) is one of the most important waste materials in the cement industry. The large amount of this material, has encouraged researchers to propose new ways to recycle and reuse it. In this paper, effects of adding cement kiln dust to the ordinary Portland cement, on the physical and mechanical properties of ordinary and lightweight concrete were investigated. Results showed that concrete containing CKD, presents lower workability and modulus of elasticity; however, improvements in strength was observed by adding particular amounts of CKD. Eventually, it was found that adding 10% of cement weight CKD is the appropriate percentage for utilizing in manufacturing ordinary and...
Study of DREAM model Operation for Predicting the Occurrence of Dust Storm in Iran
, M.Sc. Thesis Sharif University of Technology ; Afshin, Hossein (Supervisor) ; Firoozabadi, Bahar (Supervisor)
Abstract
In this study, DREAM model operation as a model to predict the occurrence of dust storms has been completed. The aim of this study is to identify capability of the model to predict dust storms in IRAN. The model has been run for June 2014 because on 2 June 2014, Tehran visited a dust storm with a speed of 111 kilometers per hour and yielded a huge economic losse. In this model, dust concentration,dust load and Aerosol Optical Depth(AOD) are calculated on an hourly basis. The model results do not captured the direct relationship between the average wind speed and dust Parameters and the model do not predict the dust storm on on 2 June 2014 in Tehran. The reason is that DREAM gets...
Zoning of Dust Hotspots and Investigation of their Formation Factors
, M.Sc. Thesis Sharif University of Technology ; Tajrishy, Massoud (Supervisor)
Abstract
Identification of dust storm hotspots using high resolution 1 km MODIS Aerosol Optical Depth (AOD) data obtained by MAIAC algorithm for a region including Iran and its neighbors, is one of the objectives of the present study. By implementing three important statistics on AOD and averaging over the last decade time period (2009-2019), dust sources of Iran, Iraq, Syria, Saudi Arabia, Oman, Afghanistan, and Pakistan were specified. These statistics include frequency of occurrence AOD>0.3, mean and coefficient of variation of aerosol optical depth. The membership rank of source zones in the set of hotspot areas has been obtained by applying the fuzzy logic approach on the three mentioned layers....
The evaluation of PM10, PM2.5, and PM1 concentrations during the Middle Eastern Dust (MED) events in Ahvaz, Iran, from april through september 2010
, Article Journal of Arid Environments ; Volume 77, Issue 1 , 2012 , Pages 72-83 ; 01401963 (ISSN) ; Naddafi, K ; Jafarzade Haghighifard, N ; Mesdaghinia, A ; Yunesian, M ; Nabizadeh, R ; Arahami, M ; Sowlat, M. H ; Yarahmadi, M ; Saki, H ; Alimohamadi, M ; Nazmara, S ; Motevalian, S. A ; Goudarzi, G ; Sharif University of Technology
Abstract
In this study, PM10, PM2.5, and PM1 concentrations were measured from April through September 2010. These measurements were made every six days and on days with dust events using a Grimm Model 1.177 aerosol spectrometer. Meteorological data were also collected. Overall mean values of 319.6 ± 407.07, 69.5 ± 83.2, and 37.02 ± 34.9 μg/m3 were obtained for PM10, PM2.5, and PM1, respectively, with corresponding maximum values of 5337.6, 910.9, and 495 μg/m3. The presence of the westerly prevailing wind implied that Iraq is the major source of dust events in this area. A total of 72 dust days and 711 dust hours occurred in the study area. The dust events occurred primarily during July. The longest...
Characterization of aerosol types over Lake Urmia Basin
, Article 2019 Central Asian DUst Conference, CADUC 2019, 8 April 2019 through 12 April 2019 ; Volume 99 , 2019 ; 25550403 (ISSN) ; Ramezanpoor, R ; Sharif University of Technology
EDP Sciences
2019
Abstract
Atmospheric aerosols affect the Earth's climate, air quality, and thus human health. This study used the Aerosol Optical Depth (AOD) and the Ångström exponent to cluster different particle types over the Lake Urmia Basin. This classification found desert dust and marine (mixed with continental or local-pollution aerosols) as two main aerosol types over the region, while their sources are not well defined. Although different air masses and wind circulation over the study domain in varied months can help to distinguish aerosol sources, measurements are crucial for a complete evaluation
Applications of single-layered graphene sheets as mass sensors and atomistic dust detectors
, Article ASME 2007 International Mechanical Engineering Congress and Exposition, IMECE 2007, 11 November 2007 through 15 November 2007 ; Volume 11 , 2007 , Pages 99-104 ; 079184305X (ISBN) ; Ahmadian, M. T ; Vafai, A ; ASME ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2007
Abstract
Molecular structural mechanics is implemented to model vibrational behavior of defect free single-layered graphene sheets (SLGSs) at constant temperature. To mimic these two-dimensional layers, zigzag and armchair models with cantilever and bridge boundary conditions are adopted. Fundamental frequencies of these nano structures are calculated, and it is perceived that they are independent of the chirality and aspect ratio. Effects of point mass and atomistic dust on the fundamental frequencies are also considered in order to investigate the possibility of using SLGSs as sensors. Results of exhibit the principle frequencies are highly sensitive to the added mass in the order of 10-6 fg....
Investigation of Dust-Causing Factors in Western Iran and Its Effects on Climate Changes
, M.Sc. Thesis Sharif University of Technology ; Agha Mohammad Hossein Tajrishi, Massoud (Supervisor)
Abstract
study has been divided into two main sections. In the first section, six climate variables have been analyzed in 15 synoptic stations in Iran’s west region through parametric and non-parametric statistical tests in order to find the climate varibility. The results illustared that, in general, there is no climate variability in the western part of Iran. Investigation of climatic indices and changes in the meteorological data in the entire study area (including a large portion of Middle East), in a 30 year period (1979-2008), is eloquent of a drought during the last 10 years of the period. In the second section, by means of the Aerosoal Index (AI) extracted from TOMS and OMI tools, it was...
Design and Simulation of Dust Control System in the Air with the FPGA
, M.Sc. Thesis Sharif University of Technology ; Vosoughi Vahdat, Bijan (Supervisor) ; Hashemi, Matin (Co-Advisor)Contribution of the Middle Eastern dust source areas to PM10 levels in urban receptors: Case study of Tehran, Iran
, Article Atmospheric Environment ; Volume 75 , 2013 , Pages 287-295 ; 13522310 (ISSN) ; Arhami, M ; Tajrishy, M ; Sharif University of Technology
2013
Abstract
The origins and evolution of the Middle Eastern dust storms which frequently impact the residents of this arid region were studied. A methodology was adapted and developed to identify the desert regions of potential dust sources and determine their contributions to PM10 concentrations in the highly-populated receptor city of Tehran, Iran. Initially, the episodes of regional dust intrusion and the resulting amounts of increase in the particulate concentrations during these episodes were determined using a statistical analyzing methodology. The dust episodes were also inspected with the aerosol index information from the Ozone Monitoring Instrument (OMI). The Hybrid Single-Particle Lagrangian...
The 20–22 February 2016 mineral dust event in Tehran, Iran: numerical modeling, remote sensing, and In Situ measurements
, Article Journal of Geophysical Research: Atmospheres ; Volume 123, Issue 10 , 27 May , 2018 , Pages 5038-5058 ; 2169897X (ISSN) ; Afshin, H ; Firoozabadi, B ; Sharif University of Technology
Blackwell Publishing Ltd
2018
Abstract
Wind erosion raises mineral dusts from dry and semidry lands and produces dust storms. Such dust masses have created numerous health and economic problems for the residents of southern, southwestern, and central parts of Iran. The main sources, movement, spread, and settlement of dust masses can be determined by solving the governing equations for aerosol transmission. Such information will be certainly useful in managerial decision-making. In this study, the dust event in Tehran on 20–22 February 2016 was studied using numerical model, Moderate Resolution Imaging Spectroradiometer satellite data, and data of ground-based stations. A comparison between the numerical results and in situ...
Six Outbursts of Comet 46P/Wirtanen
, Article Planetary Science Journal ; Volume 2, Issue 4 , 2021 ; 26323338 (ISSN) ; Farnham, T. L ; Li, J.-Y ; Bodewits, D ; Snodgrass, C ; Allen, J ; Bellm, E. C ; Coughlin, M. W ; Drake, A. J ; Duev, D. A ; Graham, M. J ; Kupfer, T ; Masci, F. J ; Reiley, D ; Walters, R ; Dominik, M ; Jørgensen, U. G ; Andrews, A. E ; Bach Møller, N ; Bozza, V ; Burgdorf, M. J ; Campbell White, J ; Dib, S ; Fujii, Y. I ; Hinse, T. C ; Hundertmark, M ; Khalouei, E ; Longa Peña, P ; Rabus, M ; Rahvar, S ; Sajadian, S ; Skottfelt, J ; Southworth, J ; Tregloan Reed, J ; Unda-Sanzana, E ; Sharif University of Technology
Web Portal IOP
2021
Abstract
Cometary activity is a manifestation of sublimation-driven processes at the surface of nuclei. However, cometary outbursts may arise from other processes that are not necessarily driven by volatiles. In order to fully understand nuclear surfaces and their evolution, we must identify the causes of cometary outbursts. In that context, we present a study of mini-outbursts of comet 46P/Wirtanen. Six events are found in our long-term lightcurve of the comet around its perihelion passage in 2018. The apparent strengths range from -0.2 to -1.6 mag in a 5″ radius aperture and correspond to dust masses between ∼104 and 106 kg, but with large uncertainties due to the unknown grain size distributions....
Investigation of Dust Emission Paths Over Lake Urmia Local Dust Spots Using the HYSPLIT Model
, M.Sc. Thesis Sharif University of Technology ; Tajrishy, Masoud (Supervisor)
Abstract
At Lake Urmia (LU) greatest extent, it was the largest lake in the Middle East and the sixth-largest saltwater lake on Earth, with a surface area of approximately 5,200 km2. The lake has shrunk to 10% of its former size due to damming of the rivers that flow into it, and the pumping of groundwater from the surrounding area. Moreover, as the lake shriks its potentional to be a major dust sources increases. A Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used to investigate and track the extent of dust emission and aerosol concentration over Lake Urmia marginal dust spots in order to identify the affected and critical areas. Also, percent movement, propagation...
The Implementation of an Operational MODIS Aerosol Retrieval Algorithm at High Spatial Resolution
, M.Sc. Thesis Sharif University of Technology ; Tajrishy, Masoud (Supervisor)
Abstract
Urmia Lake is one of the largest permanent hypersaline lakes in the world. Since Urmia Lake is faced with drying phenomena, the release of dust from its surface is expected. The most appropriate technique on dust storms is the remote sensing technique. One of the most popular parameter that provides the integrated information over a vertical column of unit cross section of this phenomenon is aerosol optical depth (AOD). Satellite remote sensing has been used to retrieve AOD over land and ocean at spatial resolutions of several to several tens of km. However, higher spatial resolution aerosol products for local scale areas have not been well-researched mainly due to the difficulty of...
Newly desertified regions in Iraq and its surrounding areas: Significant novel sources of global dust particles
, Article Journal of Arid Environments ; Volume 116 , May , 2015 , Pages 1-10 ; 01401963 (ISSN) ; Karimi, N ; Ariya, P. A ; Sharif University of Technology
Academic Press
2015
Abstract
Using the newly developed Middle East Dust Index (MEDI) applied to MODIS satellite data, we consider a relationship between the recent desertified regions, over the past three decades, and the dust source points identified during the period of 2001-2012. Results indicate that major source points are located in Iraq and Syria, and by implementing the spectral mixture analysis on the Landsat TM images (1984 and 2012), a novel desertification map was extracted. Results of this study indicate for the first time that c.a., 39% of all detected source points are located in this newly anthropogenically desertified area. Using extracted indices for Deep Blue algorithm, dust sources were classified...
Applications of single-layered graphene sheets as mass sensors and atomistic dust detectors
, Article Solid State Communications ; Volume 145, Issue 4 , 2008 , Pages 168-172 ; 00381098 (ISSN) ; Ahmadian, M. T ; Vafai, A ; Sharif University of Technology
2008
Abstract
Molecular structural mechanics is implemented to model the vibrational behavior of defect-free single-layered graphene sheets (SLGSs) at constant temperature. To mimic these two-dimensional layers, zigzag and armchair models with cantilever and bridge boundary conditions are adopted. Fundamental frequencies of these nanostructures are calculated, and it is perceived that they are independent of the chirality and aspect ratio. The effects of point mass and atomistic dust on the fundamental frequencies are also considered in order to investigate the possibility of using SLGSs as sensors. The results show that the principal frequencies are highly sensitive to an added mass of the order of 1 0-...
Contribution of Iraqi and Syrian dust storms on particulate matter concentration during a dust storm episode in receptor cities: Case study of Tehran
, Article Atmospheric Environment ; Volume 222 , 2020 ; Arhami, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Frequent dust storms originated from Middle Eastern deserts impact major cities in Iran, including Tehran. Previous studies identified Iraqi and Syrian deserts as the main cross-border contributors to Tehran Particulate Matter (PM) levels. In this study, the contribution of Iraqi and Syrian dust storms to Tehran's PM10 and PM2.5 concentration were assessed during a dust storm episode. Initially, a dust storm event was identified through the statistical analysis of the recorded air pollution data at Tehran's monitoring stations and the visual inspection of the satellite images. A combination of CMAQ/WRF/SMOKE modeling systems was used to simulate PM concentrations from Tehran local sources...
Dust concentration over a semi-arid region: parametric study and establishment of new empirical models
, Article Atmospheric Research ; Volume 243 , 1 October , 2020 ; Afshin, H ; Firoozabadi, B ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In recent years, the city of Tehran, Iran's capital, has encountered numerous dust events so that the dust concentration of PM10 has reached even more than 800 μg m−3. This emphasizes the importance of the statistical study of dust in Tehran and the development of correlations for estimating dust concentration of PM10. In the present study, by evaluating the data measured during dust observations over the years 2013–2016 in Tehran, new statistical models are established for estimating PM10 concentration in terms of horizontal visibility and MODIS AOD. Firstly, simple nonlinear regression models between dust concentration of PM10 and horizontal visibility as well as MODIS AOD are developed....