Search results for: gas to dust ratio

Authors: Labiba Zerari Bourafa, Djebar Mohamed Reda, Berrebah Houria, Khadri Sihem, Chiheb Linda

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The study of the effect of metal dust (pollutants) was performed on higher plant white beans Phaseolus vulgaris; the experience took place in cellular toxicology laboratory (in vitro culture). The seeds of the bean Phaseolus vulgaris are cultured in a metal contaminated dust medium (a single treatment by different increasing doses), at a rate of 10 seeds per box, for 10 days. The measurement of morpho-metric parameters is performed during the first 96 hours that follow the germination; while the dosage of the proline, the protein content and histological sections are formed on the tenth day (240 h). All morpho-metric and biochemical parameters measured were highly disturbed by metal dust; histological sections confirm this disurbance.

Keywords: conductive fabrics, metal dust, osmoticums, roots, Phaseolus vulgaris

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Authors: Hocine Benabid, M. F. Ghorab

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The exploration of open pit mines and quarries has always been important resources that provide many valuable needed minerals but very often accompanied by large amounts of dust rejected into the air and also many other negative environmental impacts. The dust remains suspended in the atmosphere before being deposited on soils, on forest trees, on plants and also on water, causing at long term allergic and respiratory diseases for residents living in the vicinity or even far away from the mines and quarries. As a consequence of this activity, dust can also disturb the photosynthetic activity of plants and affect water quality. It is for these reasons and because of the intensification of these activities that our motivations have become larger to deal with this kind of topic, which is becoming nowadays an environmental and health concern for almost every country in the world.

Keywords: mines, dust, environmental impacts, environmental concern

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Authors: Nasim Hossein Hamzeh, Karim Shukurov, Abbas Ranjbar Saadat Abadi, Alaa Mhawish, Christian Opp

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Deserts are the main dust sources in the world. Also, recently driedLake beds have caused environmental problems inthe surrounding areas in the world. In this study, the Urmia Lake was the source of dustfromApril 24 to April 25, 2017.The local dust storm was combined with another large-scale dust storm that originated from Saudi Arabia and Iraq 1-2 days earlier. Synoptic investigation revealed that the severe dust storm was made by a strong Black Sea cyclone and a low-pressure system over the Middle East and Central Iraq in conjunction a high-pressure system and associated with a high gradient contour and a quasi-stationary long-wave trough over the east and south of the Mediterranean Sea. Based on HYSPLIT 72 hours backward and forward trajectories, the most probable dust transport routes to and from the Urmia Lake region are estimated. Using the concentration weighted trajectory (CWT) method based on 24 hours backward and 24 hours forward trajectories, the spatial distributions of potential sources of PM10 observed in the Urmia Lake region on April 23-26, 2017. Also, the vertical profile of dust particles using the WRF-Chem model with two dust schemes showed dust ascending up to 5 km from the lake. Also, the dust schemes outputs shows that the PM10 fluctuating changes are 12 hours earlier than the measured surface PM10 at five air pollution monitoring stations around the Urmia Lake in 23-26 April 2017.

Keywords: dust storm, synoptic investigation, WRF-chem model, urmia lake, lagrangian trajectory

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Authors: Sahar Elkaee Behjati

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Air pollution, particularly with dust, is one of the biggest issues Tehran is dealing with, and the city's green space which consists of trees has a critical role in absorption of it. The question this study aimed to investigate was which tree species the highest uptake capacity of the dust and carbon have suspended in the air. On this basis, 30 samples of trees from two different districts in Tehran were collected, and after washing and centrifuging, the samples were oven dried. The results of the study revealed that Ulmus minor had the highest amount of deposited dust in both districts. In addition, it was found that in Chamran district Ailanthus altissima and in Gandi district Ulmus minor has had the highest absorption of deposited carbon. Therefore, it could be argued that decision making on the selection of species for urban green spaces should take the above-mentioned parameters into account.

Keywords: dust, leaves, uptake total carbon, Tehran, tree species

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Authors: Sandya Mummullage, Prasanna Egodawatta, Ashantha Goonetilleke, Godwin A. Ayoko

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Urban road dust comprises of a range of potentially toxic metal elements and plays a critical role in degrading urban receiving water quality. Hence, assessing the metal composition and concentration in urban road dust is a high priority. This study investigated the variability of metal composition and concentrations in road dust in four different urban land uses in Gold Coast, Australia. Samples from 16 road sites were collected and tested for selected 12 metal species. The data set was analyzed using both univariate and multivariate techniques. Outcomes of the data analysis revealed that the metal concentrations inroad dust differs considerably within and between different land uses. Iron, aluminum, magnesium and zinc are the most abundant in urban land uses. It was also noted that metal species such as titanium, nickel, copper, and zinc have the highest concentrations in industrial land use. The study outcomes revealed that soil and traffic related sources as key sources of metals deposited on road surfaces.

Keywords: metals build-up, pollutant accumulation, stormwater quality, urban road dust

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Authors: Popoola M. Oyenola

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Concrete plays the important role and a huge percentage of concrete is being utilized in every construction practices. Natural river sand is one of the major ingredients of concrete, is becoming expensive due to excessive cost of accessibility from sources. Also large scale depletion of sources creates environmental problems. Therefore, there is a need of economic alternative materials. Quarry dust is a waste obtained during quarrying process. It has been rampantly used in different construction practices and could be used as an effective fine aggregate instead of river sand. Partial and total replacement of fine aggregate in conventional concrete with quarry dust has been empirically conducted with the view to examining primarily the compressive strength of the resulting composite and possible total utilization of quarry dust as fine aggregate in the production of medium grade concrete. The results of the study showed that its specific gravity, porosity and water absorption showed satisfactory performance. The percentage replacement of natural river sand with quarry dust for a designed strength of 25N/mm2 varied at intervals of 10% up to a maximum value of 100%. A total of 132 cubes of 150 x 150 x 150mm were cast and tested at 7, 14 and 28 days of hydration. Compressive strength increases with curing age in all the mixes. Compressive strength decreases with increase in percentage of quarry dust. Generally the compressive strength of concrete incorporating quarry dust attained strength of 22.47 N/mm2 after 28 days which makes it a suitable aggregate for the production medium grade concrete.

Keywords: quarry dust, concrete, aggregates, compressive strength

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Authors: Wilhelm Hoeflinger, Thomas Laminger, Johannes Wolfslehner

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For vacuum cleaned dust filters, used e. g. in textile industry, there exist no calculation methods to determine design parameters (e. g. traverse speed of the nozzle, filter area...). In this work a method to calculate the optimum traverse speed of the nozzle of an industrial-size flat dust filter at a given mean pressure drop and filter face velocity was elaborated. Well-known equations for the design of a cleanable multi-chamber bag-house-filter were modified in order to take into account a continuously regeneration of a dust filter by a nozzle. Thereby, the specific filter medium resistance and the specific cake resistance values are needed which can be derived from filter tests under constant operation conditions. A lab-scale filter test rig was used to derive the specific filter media resistance value and the specific cake resistance value for vacuum cleaned filter operation. Three different filter media were tested and the determined parameters were compared to each other.

Keywords: design of dust filter, dust removing, filter regeneration, operation parameters

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Authors: Ayman Othman, Tallat Abd el Wahed

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The current research is directed towards studying the creep compliance characteristics of asphalt concrete mixtures modified with cement dust. This study can aid in assessing the permanent deformation potential of asphalt concrete mixtures. Cement dust was added to the mixture as mineral filler and compared with regular lime stone filler. A power law model was used to characterize the creep compliance behavior of the studied mixtures. Creep testing results have revealed that the creep compliance power law parameters have a strong relationship with mixture type. Testing results of the studied mixtures, as indicated by the creep compliance parameters revealed an enhancement in the creep resistance, Marshall stability, indirect tensile strength and compressive strength for cement dust mixtures as compared to mixtures with traditional lime stone filler. It is concluded that cement dust can be successfully used to decrease the potential of asphalt concrete mixture to permanent deformation and improve its mechanical properties. This is in addition to the environmental benefits that can be gained when using cement dust in asphalt paving technology.

Keywords: cement dust, asphalt concrete mixtures, creep compliance, Marshall stability, indirect tensile strength, compressive strength

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Authors: N. Gigauri, V. Kukhalashvili, A. Surmava, L. Intskirveli, L. Gverdtsiteli

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Tbilisi, a large city of the South Caucasus, is a junction point connecting Asia and Europe, Russia and republics of the Asia Minor. Over the last years, its atmosphere has been experienced an increasing anthropogenic load. Numerical modeling method is used for study of Tbilisi atmospheric air pollution. By means of 3D non-linear non-steady numerical model a peculiarity of city atmosphere pollution is investigated during background western light air. Dust concentration spatial and time changes are determined. There are identified the zones of high, average and less pollution, dust accumulation areas, transfer directions etc. By numerical modeling, there is shown that the process of air pollution by the dust proceeds in four stages, and they depend on the intensity of motor traffic, the micro-relief of the city, and the location of city mains. In the interval of time 06:00-09:00 the intensive growth, 09:00-15:00 a constancy or weak decrease, 18:00-21:00 an increase, and from 21:00 to 06:00 a reduction of the dust concentrations take place. The highly polluted areas are located in the vicinity of the city center and at some peripherical territories of the city, where the maximum dust concentration at 9PM is equal to 2 maximum allowable concentrations. The similar investigations conducted in case of various meteorological situations will enable us to compile the map of background urban pollution and to elaborate practical measures for ambient air protection.

Keywords: air pollution, dust, numerical modeling, urban

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Authors: Voss Harrigan, Korey Carter, Mohammad Reza Shaeri

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Detrimental effects of lunar dust on space hardware, spacesuits, and astronauts’ health have been already identified during Apollo missions. Developing effective dust mitigation technologies is critically important for successful space exploration and related missions in NASA applications. In this study, an electrostatic cleaning system (ECS) integrated with a negatively ionized Thunderon brush was developed to mitigate small-sized lunar dust particles with diameters ranging from 0.04 µm to 35 µm, and the mean and median size of 7 µm and 5 µm, respectively. It was found that the frequency pulses of the negative ion generator caused particles to stick to the Thunderon bristles and repel between the pulses. The brush was used manually to ensure that particles were removed from areas where the ECS failed to mitigate the lunar simulant. The acquired data demonstrated that the developed system removed over 91-96% of the lunar dust particles. The present study was performed as a proof-of-concept to enhance the cleaning performance of ECSs by integrating a brushing process. Suggestions were made to further improve the performance of the developed technology through future research.

Keywords: lunar dust mitigation, electrostatic cleaning system, Brushing, Thunderon brush, cleaning rate

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Authors: S. M. Ahuja

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A Rice Sheller is used for obtaining polished white rice from paddy. There are about 3000 Rice Shellers in Punjab and 50000 in India. During the process of shelling lot of dust is emitted from different unit operations like paddy silo, paddy shaker, bucket elevators, huskers, paddy separator etc. These dust emissions have adverse effect on the health of the workers and the wear and tear of the shelling machinery is also fast. All the dust emissions spewing out of these unit operations of a rice Sheller were contained by providing suitable hoods and enclosures while ensuring their workability. These were sucked by providing an induced draft fan followed by a high efficiency cyclone separator that has got an overall dust collection efficiency of more than 90 %. This cyclone separator replaced two cyclone separators and a filter bag house, which the Rice Sheller was already having. The dust concentration in the stack after the installation of cyclone separator is well within the stipulated standards. Besides controlling pollution there is improvement in the quality of products like bran and the life of shelling machinery has also enhanced. The payback period of this technology is less than four shelling months.

Keywords: air pollution, cyclone separator, pneumatic conveying, rice shellers

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Authors: Johnson Rotimi Oluremi, A. Adedayo Adegbola, A. Samson Adediran, O. Solomon Oladapo

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Spent engine oil contains heavy metals and polycyclic aromatic hydrocarbons which contribute to chronic health hazards, poor soil aeration, immobilisation of nutrients and lowering of pH in soil. It affects geotechnical properties of lateritic soil thereby constituting geotechnical and foundation problems. This study is therefore based on the stabilization of spent engine oil (SEO) contaminated lateritic soil using cement kiln dust (CKD) as a mean of restoring it to its pristine state. Geotechnical tests which include sieve analysis, atterberg limit, compaction, California bearing ratio and unconfined compressive strength tests were carried out on the natural, SEO contaminated and CKD stabilized SEO contaminated lateritic soil samples. The natural soil classified as A-2-7 (2) by AASHTO classification and GC according to the Unified Soil Classification System changed to A-4 non-plastic soil due to SEO contaminated even under the influence of CKD it remained unchanged. However, the maximum dry density (MDD) of the SEO contaminated soil increased while the optimum moisture content (OMC) behaved vice versa with the increase in the percentages of CKD. Similarly, the bearing strength of the stabilized SEO contaminated soil measured by California Bearing Ratio (CBR) increased with percentage increment in CKD. In conclusion, spent engine oil has a detrimental effect on the geotechnical properties of the lateritic soil sample but which can be remediated using 10% CKD as a stand alone admixture in stabilizing spent engine oil contaminated soil.

Keywords: spent engine oil, lateritic soil, cement kiln dust, stabilization, compaction, unconfined compressive strength

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Authors: Muhammad Munawar

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Pavement destruction is normally associated with the horizontal relocation of subgrade because of pavement engrossing water and inordinate avoidance and differential settlement of material underneath the pavement. The aim of the research is to study the effect of the additives (rockdust) on the stability and the increase of bearing capacity of selected soils in Mardan City. The physical, chemical and designing properties of soil were contemplated, and the soil was treated with added admixture rockdust with the goal of stabilizing the local soil. The stabilization or modification of soil is done by blending of rock dust to soils in the scope of 0 to 85% by the rate increment of 5%, 10%, and 15% individually. The following test was done for treated sample: Atterberg limits (liquid limit, plasticity index, plastic limit), standard compaction test, the California bearing test and the direct shear test. The results demonstrated that the gradation of soil is narrow from the particle size analysis. Plasticity index (P.I), Liquid limit (L.L) and plastic limit (P.L) were shown reduction with the addition of Rock dust. It was concluded that the maximum dry density is increasing with the addition of rockdust up to 10%, beyond 10%, it shows reduction in their content. It was discovered that the Cohesion C diminished, the angle of internal friction and the California bearing ratio (C.B.R) was improved with the addition of Rock dust. The investigation demonstrated that the best stabilizer for the contextual investigation (Toru road Mardan) is the rock dust and the ideal dosage is 10 %.

Keywords: rockdust, stabilization, modification, CBR

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Authors: Iyad Muslih, Azzah Alkhalailah, Ali Merdji

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Photovoltaic efficiency is highly affected by dust accumulation; the dust particles prevent direct solar radiation from reaching the panel surface; therefore a reduction in output power will occur. A study of dust and soiling accumulation effect on the output power of PV panels was conducted for different periods of time from May to October in three countries of the MENA region, Jordan, Egypt, and Algeria, under local weather conditions. This study leads to build a more realistic equation to estimate the power reduction as a function of time. This logarithmic function shows the high reduction in power in the first days with 10% reduction in output power compared to the reference system, where it reaches a steady state value after 60 days to reach a maximum value of 30%.

Keywords: solar energy, PV system, soiling, MENA

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Authors: Kanika Taneja, V. K. Soni, Kafeel Ahmad, Shamshad Ahmad

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A severe dust storm generated from a western disturbance over north Pakistan and adjoining Afghanistan affected the north-west region of India between May 28 and 31, 2014, resulting in significant reductions in air quality and visibility. The air quality of the affected region degraded drastically. PM10 concentration peaked at a very high value of around 1018 μgm-3 during dust storm hours of May 30, 2014 at New Delhi. The present study depicts aerosol optical properties monitored during the dust days using ground based multi-wavelength Sky radiometer over the National Capital Region of India. High Aerosol Optical Depth (AOD) at 500 nm was observed as 1.356 ± 0.19 at New Delhi while Angstrom exponent (Alpha) dropped to 0.287 on May 30, 2014. The variation in the Single Scattering Albedo (SSA) and real n(λ) and imaginary k(λ) parts of the refractive index indicated that the dust event influences the optical state to be more absorbing. The single scattering albedo, refractive index, volume size distribution and asymmetry parameter (ASY) values suggested that dust aerosols were predominant over the anthropogenic aerosols in the urban environment of New Delhi. The large reduction in the radiative flux at the surface level caused significant cooling at the surface. Direct Aerosol Radiative Forcing (DARF) was calculated using a radiative transfer model during the dust period. A consistent increase in surface cooling was evident, ranging from -31 Wm-2 to -82 Wm-2 and an increase in heating of the atmosphere from 15 Wm-2 to 92 Wm-2 and -2 Wm-2 to 10 Wm-2 at top of the atmosphere.

Keywords: aerosol optical properties, dust storm, radiative transfer model, sky radiometer

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Authors: J. Hemanth, B. G. Shivaprakash, S. V. Dinesh

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The locally available Lateritic soil in Dakshina Kanadda and Udupi districts are traditionally being used as building blocks for construction purpose but they do not meet the conventional requirements (L L ≤ 25% & P I ≤6%) and desired four days soaked CBR value to be used as a sub-base course material in pavements. In order to improve its properties to satisfy the Atterberg’s Limits, the soil is blended with sand, cement and quarry dust at various percentages and also to meet the CBR strength requirements, individual and combined gradation of various sized aggregates along with Laterite soil and other filler materials has been done for coarse graded granular sub-base materials (Grading II and Grading III). The effect of additives blended with lateritic soil and aggregates are studied in terms of Atterberg’s limits, compaction, California Bearing Ratio (CBR), and permeability. It has been observed that the addition of sand, cement and quarry dust are found to be effective in improving Atterberg’s limits, CBR values, and permeability values. The obtained CBR and permeability values of Grading III, and Grading II materials found to be sufficient to be used as sub-base course for low volume roads and high volume roads respectively.

Keywords: lateritic soil, sand, quarry dust, gradation, sub-base course, permeability

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Authors: A. M. Jungudo, M. A. Lasan

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Affordable housing has long been one of the basic necessities of life to man. The ever rising prices of building materials are one of the major causes of housing shortage in many developing countries. Breaching the gap of housing needs in developing countries like Nigeria is an awaiting task longing for attention. This is due to lack of research in the development of local materials that will suit the troubled economies of these countries. The use of earth material to meet the housing needs is a sustainable option and its material is freely available universally. However, people are doubtful of using the earth material due to its modest outlook and uncertain durability. This research aims at enhancing the durability of Compressed Earth Bricks (CEBs) using stone dust as a stabilizer. The result indicates that partial replacement of lateritic soil with stone dust at 30% improves its compressive strength along with abrasive resistance.

Keywords: earth construction, durability, stone dust, sustainable

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Authors: Frederick Anlimah, Vinod Gopaldasani, Catherine MacPhail, Brian Davies

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The construction industry, particularly tunnel construction, exposes workers to respirable crystalline silica (RCS), which can cause incurable illnesses such as silicosis and lung cancer. Despite various control measures, exposures remain inadequately controlled. This research aimed to examine what workers on a tunnelling project in Australia think should be done to reduce exposure to dust to protect them from RCS exposure. A qualitative research approach consisting of interviews and focus group discussions was employed for this research. The preliminary analysis of the data reveals a diverse array of solutions proposed to address the different sociotechnical factors that present challenges for effectively reducing dust exposure. Solutions are proposed to address challenges such as cost, time pressure, low-risk perception, inadequate awareness, inadequate enforcement and compliance with personal protective equipment. The findings highlight the need to make dust control a level playing field for all contractors during the bidding process, with more collaboration and enforcement after the signing of contracts. The research highlights that although improvements have been made in the past years regarding dust controls, many opportunities exist to reduce worker exposure to RCS.

Keywords: tunnel, respirable crystalline silica, RCS, dust exposure, personal protective equipment, worker perspectives

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Authors: K. Alafogiannis, E. E. Houssos, E. Anagnostou, G. Kouvarakis, N. Mihalopoulos, A. Fotiadi

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The Mediterranean basin is an area where different aerosol types coexist, including urban/industrial, desert dust, biomass burning and marine particles. Particularly, mineral dust aerosols, mostly originated from North African deserts, significantly contribute to high aerosol loads above the Mediterranean. Dust transport, controlled by the variation of the atmospheric circulation throughout the year, results in a strong spatial and temporal variability of aerosol properties. In this study, the synoptic conditions which favor dust transport over the Eastern Mediterranean are thoroughly investigated. For this reason, three datasets are employed. Firstly, ground-based daily data of aerosol properties, namely Aerosol Optical Thickness (AOT), Ångström exponent (α440-870) and fine fraction from the FORTH-AERONET (Aerosol Robotic Network) station along with measurements of PM10 concentrations from Finokalia station, for the period 2003-2011, are used to identify days with high coarse aerosol load (episodes) over Crete. Then, geopotential height at 1000, 850 and 700 hPa levels obtained from the NCEP/NCAR Reanalysis Project, are utilized to depict the atmospheric circulation during the identified episodes. Additionally, air-mass back trajectories, calculated by HYSPLIT, are used to verify the origin of aerosols from neighbouring deserts. For the 227 identified dust episodes, the statistical methods of Factor and Cluster Analysis are applied on the corresponding atmospheric circulation data to reveal the main types of the synoptic conditions favouring dust transport towards Crete (Eastern Mediterranean). The 227 cases are classified into 11 distinct types (clusters). Dust episodes in Eastern Mediterranean, are found to be more frequent (52%) in spring with a secondary maximum in autumn. The main characteristic of the atmospheric circulation associated with dust episodes, is the presence of a low-pressure system at surface, either in southwestern Europe or western/central Mediterranean, which induces a southerly air flow favouring dust transport from African deserts. The exact position and the intensity of the low-pressure system vary notably among clusters. More rarely dust may originate from deserts of Arabian Peninsula.

Keywords: aerosols, atmospheric circulation, dust particles, Eastern Mediterranean

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Authors: Saeed Farhadypour, Majid Azadi, Habibolla Sayyari, Mahmood Mosavi, Shahram Irani, Aliakbar Bidokhti, Omid Alizadeh Choobari, Ziba Hamidi

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In the recent decades, frequencies of dust events have increased significantly in west and south west of Iran. First, a survey on the dust events during the period (1990-2013) is investigated using historical dust data collected at 6 weather stations scattered over west and south-west of Iran. After statistical analysis of the observational data, one of the most severe dust storm event that occurred in the region from 3rd to 6th July 2009, is selected and analyzed. WRF-Chem model is used to simulate the amount of PM10 and how to transport it to the areas. The initial and lateral boundary conditions for model obtained from GFS data with 0.5°×0.5° spatial resolution. In the simulation, two aerosol schemas (GOCART and MADE/SORGAM) with 3 options (chem_opt=106,300 and 303) were evaluated. Results of the statistical analysis of the historical data showed that south west of Iran has high frequency of dust events, so that Bushehr station has the highest frequency between stations and Urmia station has the lowest frequency. Also in the period of 1990 to 2013, the years 2009 and 1998 with the amounts of 3221 and 100 respectively had the highest and lowest dust events and according to the monthly variation, June and July had the highest frequency of dust events and December had the lowest frequency. Besides, model results showed that the MADE / SORGAM scheme has predicted values and trends of PM10 better than the other schemes and has showed the better performance in comparison with the observations. Finally, distribution of PM10 and the wind surface maps obtained from numerical modeling showed that the formation of dust plums formed in Iraq and Syria and also transportation of them to the West and Southwest of Iran. In addition, comparing the MODIS satellite image acquired on 4th July 2009 with model output at the same time showed the good ability of WRF-Chem in simulating spatial distribution of dust.

Keywords: dust storm, MADE/SORGAM scheme, PM10, WRF-Chem

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Authors: K. Rumchev, S. Gilbey

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Airborne particulate matter is a known hazard to human health, with a considerable body of evidence linking agricultural dust exposures to adverse human health effects in exposed populations. It is also known that agricultural workers are exposed to high levels of soil dust and other types of airborne particulate matter within the farming environment. The aim of this study was to examine exposure to agricultural dust among farm workers during the seeding season. Twenty-one wheat-belt farms consented to participate in the study with 30 workers being monitored for dust exposure whilst seeding or undertaking seeding associated tasks. Each farm was visited once and farmers’ were asked to wear a personal air sampler for a 4-hour sampling period. Simultaneous, real-time, tractor cabin air quality monitoring was also undertaken. Data for this study was collected using real-time aerosol dust monitors to determine in-tractor cabin PM exposure to five size fractions (total, PM10, respirable, PM2.5 and PM1), and personal sampling was undertaken to establish individual exposure to inhalable and respirable dust concentrations. The study established a significant difference between personal exposures and simultaneous real-time in-cabin exposures for both inhalable and respirable fractions. No significant difference was shown between in-cabin and personal inhalable dust concentrations during seeding and spraying tasks, although both in-cabin and personal concentrations were two times greater for seeding than spraying. Future research should focus on educating and providing farm owners and workers with more information on adopting safe work practices to minimise harmful exposures to agricultural dust.

Keywords: agriculture, air quality, Australia, particulate matter

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Authors: Siriluk Ruangrungrote

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Analyses of available data from MFR-7 measurement were performed and discussed on the study of tropospheric aerosol and its consequence in Thailand. Since, ASSA (w) is one of the most important parameters for a determination of aerosol effect on radioactive forcing. Here the estimation of w was directly determined in terms of the ratio of aerosol scattering optical depth to aerosol extinction optical depth (ωscat/ωext) without any utilization of aerosol computer code models. This is of benefit for providing the elimination of uncertainty causing by the modeling assumptions and the estimation of actual aerosol input data. Diurnal w of 5 cloudless-days in winter and early summer at 5 distinct wavelengths of 415, 500, 615, 673 and 870 nm with the consideration of Rayleigh scattering and atmospheric column NO2 and Ozone contents were investigated, respectively. Besides, the tendency of spectral dependence of ω representing two seasons was observed. The characteristic of spectral results reveals that during wintertime the atmosphere of the inland rural vicinity for the period of measurement possibly dominated with a lesser amount of soil dust aerosols loading than one in early summer. Hence, the major aerosol loading particularly in summer was subject to a mixture of both soil dust and biomass burning aerosols.

Keywords: aerosol scattering optical depth, aerosol extinction optical depth, biomass burning aerosol, soil dust aerosol

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Authors: Abdulmalik Altuwayjiri, Milad Pirhadi, Mohammed Kalafy, Badr Alharbi, Constantinos Sioutas

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In this study, we investigated the chemical and toxicological characteristics of PM10 in the metropolitan area of Riyadh, Saudi Arabia. PM10 samples were collected on quartz and teflon filters during cold (December 2019–April 2020) and warm (May 2020–August 2020) seasons, including dust and non-dust events. The PM10 constituents were chemically analyzed for their metal, inorganic ions, and elemental and organic carbon (EC/OC) contents. Additionally, the PM10 oxidative potential was measured by means of the dithiothreitol (DTT) assay. Our findings revealed that the oxidative potential of the collected ambient PM10 samples was significantly higher than those measured in many urban areas worldwide. The oxidative potential of the collected ambient PM¹⁰⁻ samples was also higher during dust episodes compared to non-dust events, mainly due to higher concentrations of metals during these events. We performed Pearson correlation analysis, principal component analysis (PCA), and multi-linear regression (MLR) to identify the most significant sources contributing to the toxicity of PM¹⁰⁻ The results of the MLR analyses indicated that the major pollution sources contributing to the oxidative potential of ambient PM10 were soil and resuspended dust emissions (identified by Al, K, Fe, and Li) (31%), followed by secondary organic aerosol (SOA) formation (traced by SO₄-² and NH+₄) (20%), and industrial activities (identified by Se and La) (19%), and traffic emissions (characterized by EC, Zn, and Cu) (17%). Results from this study underscore the impact of transported dust emissions on the oxidative potential of ambient PM10 in Riyadh and can be helpful in adopting appropriate public health policies regarding detrimental outcomes of exposure to PM₁₀-

Keywords: ambient PM10, oxidative potential, source apportionment, Riyadh, dust episodes

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Authors: Jiraphorn Satechan, Thanaphon Khamthieng, Warunee Phanwong

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This action research aimed at designing and developing the cleaning equipment to preventing dust diffusion of bus air filter. Quantitative and qualitative data collection methods were used to conduct data from October 1st, 2018 to September 30th, 2019. All of participants were male (100.0%) with aged 40- 49 years and 57.15%, of them finish bachelor degree. 71.43% of them was a driver and 57.15% of them had the working experience between 10 and 15 years. Research revealed that the participants assessed the quality of the bus air filter cleaning equipment for preventing dust diffusion at a moderate level (σ= 0.29), and 71.43 of them also suggested the development methods in order to improve the quality of bus air filters cleaning equipment as follows: 1) to install the circuit breaker for cutting the electricity and controlling the on-off of the equipment and to change the motor to the DC system, 2) should install the display monitor for wind pressure and electricity system as well as to install the air pressure gauge, 3) should install the tank lid lock for preventing air leakage and dust diffusion by increasing the blowing force and sucking power, 4) to stabilize the holding points for preventing the filter shaking while rotating and blowing for cleaning and to reduce the rotation speed in order to allow the filters to move slowly for the air system to blow for cleaning more thoroughly, 5) the amount of dust should be measured before and after cleaning and should be designed the cleaning equipment to be able to clean with a variety of filters, and sizes. Moreover, the light-weight materials should be used to build the cleaning equipment and the wheels should be installed at the base of the equipment in order to make it easier to move.

Keywords: Cleaning Equipment, Bus Air Filters, Preventing Dust Diffusion, Innovation

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Authors: Abhilasha Mishra, Neha Bhatt

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Super-hydrophobicity is an effect in which a surface roughness and chemical composition are combined to produce unusual water and dust repellent surface. The super-hydrophobic surface is widely used in many applications such as windshields of the automobile, aircraft, lens, solar cells, roofing, boat hull, paints, etc. Four coating solutions were prepared by varying compositions of 1,1,1,3,3,3 hexametyldisilazane (HDMS) and tetraethylorthosilicate (TEOS) sol. These solutions were coated on glass slides by a spin coating method and etched at a high temperature ranging 250 -350 oC. All the coatings were studied for its different properties like water repellent, anti-dust, and transparency and contact angle measurements. Stability of coatings was also studied with respect to temperature, external environment, and pH. It was found that all coatings impart a significant super-hydrophobicity on a glass surface with contact angle ranging from 156o to 162o and have good stability in the external environment. The results of the different coatings were observed and compared with each other. On increasing layers of coatings the super-hydrophobicity and anti-dust properties increases but after 3 coatings the transparency of coating starts decreasing.

Keywords: super-hydrophobic, contact angle, coating, anti-dust

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Authors: Kelebaone Tsamaase, Rapelang Kemoabe, Japhet Sakala, Edward Rakgati, Ishmael Zibani

Abstract:

Increasing demand for energy, depletion of non-renewable energy, effects of climate change, the abundance of renewable energy such as solar energy have increased the interest in investing in renewable energies, in particular solar photovoltaic (PV) energy. Solar photovoltaic energy systems as part of clean technology are considered to be environmentally friendly, freely available, offer clean production systems, long term costs benefits as opposed to conventional sources, and are the attractive power source for a wide range of applications in remote areas where there is no easy access to the national grid. To get maximum electrical power, maximum solar power should penetrate the module and be converted accordingly. However, some environmental and other geographical related factors reduce the electrical power. One of them is dust which accumulates on the surface of the module and forming a dust layer and in the process obstructing the solar power from penetrating PV module. This study intends to improve the performance of solar photovoltaic (PV) energy modules by establishing soil accumulation effects correction factor from dust characteristics and properties, and also from dust accumulation and retention pattern on PV module surface. The non-urban dry deposition flux model was adapted to determine monthly and yearly dust accumulation pattern. Consideration was done on prevailing environmental and other geographical conditions. Preliminary results showed that cumulative dust settlement increased during the months of July to October leading to a higher drop in module electrical output power.

Keywords: dust, electrical power output, PV module, soil correction factor

Procedia PDF Downloads 133

Authors: Adel Belal, Sameh Aboelsoud, Mohy Elmashad, Mohammed Abdelmonem

Abstract:

The two main criteria that control the design and performance of footings are bearing capacity and settlement of soil. In soft soils, the construction of buildings, storage tanks, warehouse, etc. on weak soils usually involves excessive settlement problems. To solve bearing capacity or reduce settlement problems, soil improvement may be considered by using different techniques, including encased cement dust–lime columns. The proposed research studies the effect of adding floating encased cement dust and lime mix columns to soft clay on the clay-bearing capacity. Four experimental tests were carried out. Columns diameters of 3.0 cm, 4.0 cm, and 5.0 cm and columns length of 60% of the clay layer thickness were used. Numerical model was constructed and verified using commercial finite element package (PLAXIS 2D, V8.5). The verified model was used to study the effect of distributing columns around the footing at different distances. The study showed that the floating cement dust lime columns enhanced the clay-bearing capacity with 262%. The numerical model showed that the columns around the footing have a limit effect on the clay improvement.

Keywords: bearing capacity, cement dust – lime columns, ground improvement, soft clay

Procedia PDF Downloads 201

Authors: Md. R. Shattique, Md. T. Zaki, Md. G. Kibria

Abstract:

Fly-ash bricks give a comprehensive solution towards recycling of fly-ash and since there is no requirement of firing to produce them, they are also eco-friendly bricks; little or no carbon-dioxide is emitted during their entire production cycle. As bricks are the most essential and widely utilized building materials in the construction industry, the significance of developing an alternate eco-friendly brick is substantial in modern times. In this paper, manufacturing and potential utilization of Fly-ash made building bricks have been studied and was found to be a prospective substitute for fired clay bricks that contribute greatly to polluting the environment. Also, a comparison between sand made and ceramic dust made Fly-ash bricks have been carried out experimentally. The ceramic dust made bricks seem to show higher compressive strength at lower unit volume weight compared to sand made Fly-ash bricks. Moreover, the water absorption capacity of ceramic dust Fly-ash bricks was lower than sand made bricks. Then finally a statistical comparison between fired clay bricks and fly-ash bricks were carried out. All the requirements for good quality building bricks are matched by the fly-ash bricks. All the facts from this study pointed out that these bricks give a new opportunity for being an alternate building material.

Keywords: coal fly-ash, ceramic dust, burnt clay bricks, sand, gypsum, absorption capacity, unit volume weight, compressive strength

Procedia PDF Downloads 422

Authors: Mustafa S. Agha, Asma M. Eshahriy

Abstract:

The propagation of electromagnetic waves in millimeter band is severely affected by rain, and dust particles in terms of attenuation and de-polarization. The computations of dust and/or sand storms require knowledge of electrical properties of the scattering particles and climate conditions at the studied region in the west north region of Libya. (Al -Khoms) To compute the effect of dust and sand particles on the propagation of electromagnetic waves, it is required to collect the sand particles carried out by the wind, measure the particles size distribution (PSD), calculate the concentration, and carry chemical analysis of the contents, then the dielectric constant can be calculated. The main object of this paper is to study the effect of sand and dust storms on wireless communication, such as microwave links, in the north region of Libya (Al -Khoms) of Libya (Nagaza stations, Al-khoms center stations, Al-khoms gateway stations) by determining of the attenuation loss per unit length and cross-polarization discrimination (XPD) change due to the effect of sand and dust storms on wireless communication systems (GSM signal). The result showed that there is some consideration that has to be taken into account in the communication power budget .

Keywords: attenuation, scattering, transmission loss, electromagnetic waves

Procedia PDF Downloads 431

Authors: S.V. Kleyn, S.Yu. Zagorodnov, А.А. Kokoulina

Abstract:

Technogenic emissions of the mining and processing complex are characterized by a high content of chemical components and solid dust particles. However, each industrial enterprise and the surrounding area have features that require refinement and parameterization. Numerous studies have shown the negative impact of fine dust PM10 and PM2.5 on the health, as well as the possibility of toxic components absorption, including heavy metals by dust particles. The target of the study was the quantitative assessment of the fractional and particle size composition of ambient air dust in the area of impact by primary magnesium production complex. Also, we tried to describe the morphology features of dust particles. Study methods. To identify the dust emission sources, the analysis of the production process has been carried out. The particulate composition of the emissions was measured using laser particle analyzer Microtrac S3500 (covered range of particle size is 20 nm to 2000 km). Particle morphology and the component composition were established by electron microscopy by scanning microscope of high resolution (magnification rate - 5 to 300 000 times) with X-ray fluorescence device S3400N ‘HITACHI’. The chemical composition was identified by X-ray analysis of the samples using an X-ray diffractometer XRD-700 ‘Shimadzu’. Determination of the dust pollution level was carried out using model calculations of emissions in the atmosphere dispersion. The calculations were verified by instrumental studies. Results of the study. The results demonstrated that the dust emissions of different technical processes are heterogeneous and fractional structure is complicated. The percentage of particle sizes up to 2.5 micrometres inclusive was ranged from 0.00 to 56.70%; particle sizes less than 10 microns inclusive – 0.00 - 85.60%; particle sizes greater than 10 microns - 14.40% -100.00%. During microscopy, the presence of nanoscale size particles has been detected. Studied dust particles are round, irregular, cubic and integral shapes. The composition of the dust includes magnesium, sodium, potassium, calcium, iron, chlorine. On the base of obtained results, it was performed the model calculations of dust emissions dispersion and establishment of the areas of fine dust РМ 10 and РМ 2.5 distribution. It was found that the dust emissions of fine powder fractions PM10 and PM2.5 are dispersed over large distances and beyond the border of the industrial site of the enterprise. The population living near the enterprise is exposed to the risk of diseases associated with dust exposure. Data are transferred to the economic entity to make decisions on the measures to minimize the risks. Exposure and risks indicators on the health are used to provide named patient health and preventive care to the citizens living in the area of negative impact of the facility.

Keywords: dust emissions, еxposure assessment, PM 10, PM 2.5

Procedia PDF Downloads 261