This paper presents an assessment on the behavior of plain carbon steel exposure to the atmosphere of Bogotá. The main climate and environmental parameters, including relative humidity (RH), temperature (T), sulphur dioxide deposition (DSO2) and particulate matter deposition (DPM) were measured. Furthermore, mass loss of AISI/SAE 1006 plain carbon steel coupons was measured along one year. In this case, coupons were exposed in eight test sites located across the city of Bogotá. Results show that the corrosion rate of carbon steel is less than 35 μm yr–1 after one year. It was found that the west part of the city has the greatest aggressivity, which has the highest levels of DPM and DSO2, related with the characteristics of the anthropogenic activities distribution across the city. A dose-response function of plain carbon steel exposure to the atmosphere of Bogotá, based on RH, T and DSO2, was obtained.
Distribution and mobility of lead and zinc atmospheric depositions in industr...INFOGAIN PUBLICATION
Heavy metal contamination is a severe environmental problem. Knowledge of the total heavy metals contents of soils is a necessary step for making an accurate appraisal and quantitative evaluation of the extent of contamination, indeed, wet and dry atmospheric deposits, plays an important role in the cycle of semi-volatile contaminants [1]. Metallurgical industries release heavy metals into the atmosphere, these last, clump together to form fines particles suspended in the air, these metals can be transported by wind via aerosol or aqueous pathway and deposited in the soil. The main aim of this work was to study the mobility and fate of lead and zinc from atmospheric deposits in contaminated soil from the foundry (ALFET) in industrial zone of Tiaret (Western Algeria) and to determine the effect of physicochemical parameters of the soil on their mobility in the topsoil. Physicochemical analysis of 35 soil samples have shown that zinc and lead levels contents in the surface layer soil (0-30 cm) vary depending on the pH, total limestone (CaCO3) and the soil water content. Results clearly show that soil texture and fine fraction (clay and sand) significantly influence mobility of Pb and Zn in soil.
IOSR Journal of Applied Chemistry (IOSR-JAC) is an open access international journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Distribution and mobility of lead and zinc atmospheric depositions in industr...INFOGAIN PUBLICATION
Heavy metal contamination is a severe environmental problem. Knowledge of the total heavy metals contents of soils is a necessary step for making an accurate appraisal and quantitative evaluation of the extent of contamination, indeed, wet and dry atmospheric deposits, plays an important role in the cycle of semi-volatile contaminants [1]. Metallurgical industries release heavy metals into the atmosphere, these last, clump together to form fines particles suspended in the air, these metals can be transported by wind via aerosol or aqueous pathway and deposited in the soil. The main aim of this work was to study the mobility and fate of lead and zinc from atmospheric deposits in contaminated soil from the foundry (ALFET) in industrial zone of Tiaret (Western Algeria) and to determine the effect of physicochemical parameters of the soil on their mobility in the topsoil. Physicochemical analysis of 35 soil samples have shown that zinc and lead levels contents in the surface layer soil (0-30 cm) vary depending on the pH, total limestone (CaCO3) and the soil water content. Results clearly show that soil texture and fine fraction (clay and sand) significantly influence mobility of Pb and Zn in soil.
IOSR Journal of Applied Chemistry (IOSR-JAC) is an open access international journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
COMPARATIVE STUDY ON HEAVY METAL CHARACTERISTICS OF LEACHATE FROM MUNICIPAL ...IJSIT Editor
Rapid urbanization and population growth are largely responsible for very high increasing rate of
solid waste in the urban areas, its proper management and recycling is major problems of Municipal
Corporation. The analytical analysis revealed that the leachate show high concentration of heavy metals viz.,
Pb, Zn, Fe, Mn and Cu. However, their high concentration in municipal solid waste leachate may cause
contaminants for environmental pollution. Therefore, present investigation deals with analyze the heavy
metals concentration in municipal solid waste leachate.
IOSR Journal of Applied Chemistry (IOSR-JAC) is an open access international journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
1 a chemometric approach for the distribution and source identification of he...BIOLOGICAL FORUM
ABSTRACT: Heavy metals in the environment may reach to toxic levels to humans and animals due to tannery effluents, but there is insufficient information about heavy metals pollution and distribution by tanneries. The distribution and sources of heavy metals in soils of Challawa industrial estate area were evaluated using multivariate statistical analysis after determining metals concentrations by atomic absorption spectroscopy. The results of the Principal Component Analysis and Hierarchical Cluster Analysis suggested that variation in heavy metals concentrations are largely related to tannery operations. The Linear Discriminant Analysis revealed that soils around the tanneries and dumpsites are having high contents of Cr, Pb, and Zn. The metal concentrations showed significant difference (P < 0.05) between tannery and control soil samples. This confirmed the contamination of soils with toxic heavy metals at specific sites of the tanneries, and indicated the need to monitor and remediate to safeguard the environment.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
pH effects on the adsorption of saxitoxin by powdered activated carbonhbuarque
Increasing occurrence of cyanotoxins in surface waters worldwide pose significant problems, including
those for drinking water utilities. In this study, the removal of saxitoxin (STX) from three different
powdered activated carbons (PACs) was studied. STX is one of the most toxic paralytic shellfish toxins
(PSTs), albeit not the most prevalent. The results showed that a wide range of non-electrostatic and
electrostatic interactions appeared to play a role in the sorption of STX on PAC, depending on the solution
pH, NOM concentration, and other factors. A bituminous coal-based PAC, that was studied in greatest
detail, showed a trend of increasing sorption capacity for STX with increasing pH. NOM appeared to
significantly inhibit adsorption when the pH was nearly neutral (e.g. 7.05), yet it had less effect at higher
pH levels of 8.2 and 10.7.
Effect of CO2 sequestration on soil liquefaction in geological pitsijiert bestjournal
This paper deals with review of the previous related research on evaluation of soil liquefaction due to Carbon sequestration by various Carbon Capture Sequestration processes in geological pits. It provides critical literature recommendations on evaluation of soil liqu efaction potential assessment. The detection of soil liquefaction by using seismic records has been developed by various researchers. With this information,the evaluation of soil liquefaction are well under stood and this lead to a more precise and confident output. Gaining support for CCS will require engaging the interest and building the support of a variety of stakeholders,each with differ ent perspectives and goals. Although,CCS builds upon a technology base developed over more than half a century by the oil and gas industry. In the past,the industrially released CO 2 had been introduced to ocean which was harming the aquatic animals. In view of this,the sequestration of CO 2 into ocean was internationally banned. Hence,now much of the Carbon sequestration process is done by various industries in geolog ical pits. This creates a major threat to the earth quake problems worldwide. With the enhanced frequenc y of earthquakes all around the world,it is presumed by many environment scientists that the CO 2 sequestration pits leads to soil liquefaction and hence it results in more frequent earth quakes. T herefore,this paper summarises,different methods to evaluate liquefaction potential of soil by usi ng studies from seismic waves generated in earth,it is also propose it is also explains different me thodology for an eco friendly technology to reduce CO 2 from environment.
Food security in a growing population with limited natural resources is one of
the most important issues of the world. Accumulation of heavy metals in food and
their concentrations increase and reaching to a risk limit can threaten human health.
The purpose of this study, is to study the heavy metals lead and cadmium in
vegetables, cultured on spinach and watercress at 10 Gardens of Ardabil. This study is
cross-sectional and 81 samples in water, soil, and spinach and watercress were
prepared during the months of June, July and August in 2015 and after preparation
according to the standard methods and using atomic absorption spectrophotometer
(Perkin Elmer) for the determination of heavy metals. SPSS software was used for data
analysis. The results showed that the mean level of lead and cadmium in all samples
were less than the EPA standard. Between studied orchards in terms of the amount of
cadmium and lead no statistically significant different was seen. The independent ttest
showed that in terms of cadmium between two species of spinach and watercress
there found a significant difference at the 5% level so that the amount of cadmium in
spinach was more than the watercress. Since the concentration of heavy metals in all
samples at second and third stages in July and August were zero, but in the first step
in June, the amount of heavy metals have been found in some samples showed that
all three samples of first cut had more contamination than second and third cut. And
in this case, the concentration of heavy metal pollution in hibernation at vegetable
gardens Ardabil is possible. The results of spinach cadmium amount in the first cut in
the three garden of viz.,3, 6 and 10 showed that in the garden (3), the amount of
cadmium in water is higher than the standard and is concentrated in spinach and the
gardens of 6 and 10 Cadmium in the soil of the gardens, is slightly higher that is
condensed in spinach thus it can be considered that spinach in terms of cadmium has
bioaccumulation.
The Influence of Vermiculite on the Uptake of Silver Nanoparticles in a Terre...Agriculture Journal IJOEAR
— The uptake of silver from silver nanoparticles in soil was investigated in the presence of increasing concentrations of Vermiculite, typical 2:1 clay. Two insect species, Acheta domesticus and Tenebrio molitor, and two plant species, Helianthus annuus and Sorghum vulgare, were exposed to silver nanoparticles in the presence of increasing concentrations of Vermiculite in soil. Silver nanoparticles were characterized using techniques including transmission electron microscopy, dynamic light scattering, and powder X-ray diffraction. The levels of silver in test species exposed to silver nanoparticles were measured using an inductively coupled plasma-optical emission spectrometer. An increase in the cation exchange capacity of soil was observed with the increase in the concentration of vermiculite in soil. The results suggested a decrease in the uptake of silver from silver nanoparticles in soil by Acheta domesticus as a function of increasing concentrations of Vermiculite in soil. No apparent trend was observed in the remaining species. Both plant species were found to accumulate silver in their roots. The translocation of silver to stems and leaves was observed in the case of Helianthus annuus. Results from this study suggest that the presence of Vermiculite in soil could possibly decrease the uptake of silver from silver nanoparticles.
Detection of the Presence of Heavy Metal Pollutants in Eleme Industrial Area ...theijes
The presenceof some heavy metal pollutants which are deposited on soil in the Eleme environment due to the operational activities of some companies in the area have been studied. Some soil samples in areas situated around industrial installations were collected and analyzed using Atomic Absorption Spectrophotometer (AAS). Results obtained show the presence and concentration distributions of nine heavy metals. The metals are Iron (Fe), Manganese (Mn), Zinc (Zn), Lead (Pb), Copper (Cu), Chromium (Cr), Cobalt (Co) and Cadmium (Cd). It was observed that over 90% of each of the metals was located in communities hosting the industrial corporations while the remaining 10% is distributed to areas away from the source or host communities. This reveals that, a link exists between the pollutants and the activities of these industries.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
COMPARATIVE STUDY ON HEAVY METAL CHARACTERISTICS OF LEACHATE FROM MUNICIPAL ...IJSIT Editor
Rapid urbanization and population growth are largely responsible for very high increasing rate of
solid waste in the urban areas, its proper management and recycling is major problems of Municipal
Corporation. The analytical analysis revealed that the leachate show high concentration of heavy metals viz.,
Pb, Zn, Fe, Mn and Cu. However, their high concentration in municipal solid waste leachate may cause
contaminants for environmental pollution. Therefore, present investigation deals with analyze the heavy
metals concentration in municipal solid waste leachate.
IOSR Journal of Applied Chemistry (IOSR-JAC) is an open access international journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
1 a chemometric approach for the distribution and source identification of he...BIOLOGICAL FORUM
ABSTRACT: Heavy metals in the environment may reach to toxic levels to humans and animals due to tannery effluents, but there is insufficient information about heavy metals pollution and distribution by tanneries. The distribution and sources of heavy metals in soils of Challawa industrial estate area were evaluated using multivariate statistical analysis after determining metals concentrations by atomic absorption spectroscopy. The results of the Principal Component Analysis and Hierarchical Cluster Analysis suggested that variation in heavy metals concentrations are largely related to tannery operations. The Linear Discriminant Analysis revealed that soils around the tanneries and dumpsites are having high contents of Cr, Pb, and Zn. The metal concentrations showed significant difference (P < 0.05) between tannery and control soil samples. This confirmed the contamination of soils with toxic heavy metals at specific sites of the tanneries, and indicated the need to monitor and remediate to safeguard the environment.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
pH effects on the adsorption of saxitoxin by powdered activated carbonhbuarque
Increasing occurrence of cyanotoxins in surface waters worldwide pose significant problems, including
those for drinking water utilities. In this study, the removal of saxitoxin (STX) from three different
powdered activated carbons (PACs) was studied. STX is one of the most toxic paralytic shellfish toxins
(PSTs), albeit not the most prevalent. The results showed that a wide range of non-electrostatic and
electrostatic interactions appeared to play a role in the sorption of STX on PAC, depending on the solution
pH, NOM concentration, and other factors. A bituminous coal-based PAC, that was studied in greatest
detail, showed a trend of increasing sorption capacity for STX with increasing pH. NOM appeared to
significantly inhibit adsorption when the pH was nearly neutral (e.g. 7.05), yet it had less effect at higher
pH levels of 8.2 and 10.7.
Effect of CO2 sequestration on soil liquefaction in geological pitsijiert bestjournal
This paper deals with review of the previous related research on evaluation of soil liquefaction due to Carbon sequestration by various Carbon Capture Sequestration processes in geological pits. It provides critical literature recommendations on evaluation of soil liqu efaction potential assessment. The detection of soil liquefaction by using seismic records has been developed by various researchers. With this information,the evaluation of soil liquefaction are well under stood and this lead to a more precise and confident output. Gaining support for CCS will require engaging the interest and building the support of a variety of stakeholders,each with differ ent perspectives and goals. Although,CCS builds upon a technology base developed over more than half a century by the oil and gas industry. In the past,the industrially released CO 2 had been introduced to ocean which was harming the aquatic animals. In view of this,the sequestration of CO 2 into ocean was internationally banned. Hence,now much of the Carbon sequestration process is done by various industries in geolog ical pits. This creates a major threat to the earth quake problems worldwide. With the enhanced frequenc y of earthquakes all around the world,it is presumed by many environment scientists that the CO 2 sequestration pits leads to soil liquefaction and hence it results in more frequent earth quakes. T herefore,this paper summarises,different methods to evaluate liquefaction potential of soil by usi ng studies from seismic waves generated in earth,it is also propose it is also explains different me thodology for an eco friendly technology to reduce CO 2 from environment.
Food security in a growing population with limited natural resources is one of
the most important issues of the world. Accumulation of heavy metals in food and
their concentrations increase and reaching to a risk limit can threaten human health.
The purpose of this study, is to study the heavy metals lead and cadmium in
vegetables, cultured on spinach and watercress at 10 Gardens of Ardabil. This study is
cross-sectional and 81 samples in water, soil, and spinach and watercress were
prepared during the months of June, July and August in 2015 and after preparation
according to the standard methods and using atomic absorption spectrophotometer
(Perkin Elmer) for the determination of heavy metals. SPSS software was used for data
analysis. The results showed that the mean level of lead and cadmium in all samples
were less than the EPA standard. Between studied orchards in terms of the amount of
cadmium and lead no statistically significant different was seen. The independent ttest
showed that in terms of cadmium between two species of spinach and watercress
there found a significant difference at the 5% level so that the amount of cadmium in
spinach was more than the watercress. Since the concentration of heavy metals in all
samples at second and third stages in July and August were zero, but in the first step
in June, the amount of heavy metals have been found in some samples showed that
all three samples of first cut had more contamination than second and third cut. And
in this case, the concentration of heavy metal pollution in hibernation at vegetable
gardens Ardabil is possible. The results of spinach cadmium amount in the first cut in
the three garden of viz.,3, 6 and 10 showed that in the garden (3), the amount of
cadmium in water is higher than the standard and is concentrated in spinach and the
gardens of 6 and 10 Cadmium in the soil of the gardens, is slightly higher that is
condensed in spinach thus it can be considered that spinach in terms of cadmium has
bioaccumulation.
The Influence of Vermiculite on the Uptake of Silver Nanoparticles in a Terre...Agriculture Journal IJOEAR
— The uptake of silver from silver nanoparticles in soil was investigated in the presence of increasing concentrations of Vermiculite, typical 2:1 clay. Two insect species, Acheta domesticus and Tenebrio molitor, and two plant species, Helianthus annuus and Sorghum vulgare, were exposed to silver nanoparticles in the presence of increasing concentrations of Vermiculite in soil. Silver nanoparticles were characterized using techniques including transmission electron microscopy, dynamic light scattering, and powder X-ray diffraction. The levels of silver in test species exposed to silver nanoparticles were measured using an inductively coupled plasma-optical emission spectrometer. An increase in the cation exchange capacity of soil was observed with the increase in the concentration of vermiculite in soil. The results suggested a decrease in the uptake of silver from silver nanoparticles in soil by Acheta domesticus as a function of increasing concentrations of Vermiculite in soil. No apparent trend was observed in the remaining species. Both plant species were found to accumulate silver in their roots. The translocation of silver to stems and leaves was observed in the case of Helianthus annuus. Results from this study suggest that the presence of Vermiculite in soil could possibly decrease the uptake of silver from silver nanoparticles.
Detection of the Presence of Heavy Metal Pollutants in Eleme Industrial Area ...theijes
The presenceof some heavy metal pollutants which are deposited on soil in the Eleme environment due to the operational activities of some companies in the area have been studied. Some soil samples in areas situated around industrial installations were collected and analyzed using Atomic Absorption Spectrophotometer (AAS). Results obtained show the presence and concentration distributions of nine heavy metals. The metals are Iron (Fe), Manganese (Mn), Zinc (Zn), Lead (Pb), Copper (Cu), Chromium (Cr), Cobalt (Co) and Cadmium (Cd). It was observed that over 90% of each of the metals was located in communities hosting the industrial corporations while the remaining 10% is distributed to areas away from the source or host communities. This reveals that, a link exists between the pollutants and the activities of these industries.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
A WIRELESS SENSOR NETWORK FOR MONITORING ATMOSPHERIC AGGRESSIVENESS IN METALSijasuc
Humid tropical climate favours the existence of a corrosive atmosphere that causes deterioration of metals.
This article describes an automated system for monitoring environmental values (temperature and relative
humidity) in order to know the time of wetness (TOW), which is key factor in determining the atmospheric
aggressiveness which are exposed the metals used, for example, in industrial facilities. System is
implemented on a wireless sensor network and the main function of the software developed is to count the
time of wetness which is considered the effective time in which metals corrode. System was designed
considering the user requirements as the selection of the frequency of measurements, the calculation of
TOW and verification of the residual energy of sensor nodes. The results show the effectiveness of the
technology used, so that, we can conclude that this type of networks represent a feasible alternative for
automated monitoring of corrosion in metals.
Analysis of Heavy Metal Pollution Based on Two-Dimensional Diffusion ModelScientific Review SR
This paper takes the propagation characteristics of heavy metals and the judgment of the location of pollution sources as the research objects, aiming to analyze the propagation characteristics of different heavy metals. Firstly, the Gaussian diffusion model is conducted to establish the propagation characteristics model of heavy metal pollutants in the atmosphere. Then, based on the law of conservation of mass and the law of two-dimensional diffusion, the two-dimensional diffusion model is adopted to establish the propagation characteristics model of heavy metals in soil moisture. According to these two models, the nonlinear differential equations are established respectively, revealing that the characteristics of the two propagation ways are related to space, time, diffusion coefficients, and other factors. Then, in the light of the propagation characteristics of different heavy metals, the least square method is applied to reduce the data calculation error and obtain the specific location of the pollution source. Finally, through establishing the three-dimensional diffusion model of heavy metal diffusion by introducing artificial control, speed and angle of prevailing wind direction, and other factors, the model is further optimized. The establishment of this model provides an important theoretical basis and guiding significance for the future study of heavy metal pollutants.
This paper takes the propagation characteristics of heavy metals and the judgment of the location of pollution
sources as the research objects, aiming to analyze the propagation characteristics of different he avy metals. Firstly,
the Gaussian diffusion model is conducted to establish the propagation characteristics model of heavy metal
pollutants in the atmosphere. Then, based on the law of conservation of mass and the law of two -dimensional
diffusion, the two-dimensional diffusion model is adopted to establish the propagation characteristics model of
heavy metals in soil moisture. According to these two models, the nonlinear differential equations are established
respectively, revealing that the characteristics of the two propagation ways are related to space, time, diffusion
coefficients, and other factors. Then, in the light of the propagation characteristics of different heavy metals, the least
square method is applied to reduce the data calculation error and obtain the specific location of the pollution source.
Finally, through establishing the three-dimensional diffusion model of heavy metal diffusion by introducing artificial
control, speed and angle of prevailing wind direction, and other factors, the mode l is further optimized. The
establishment of this model provides an important theoretical basis and guiding significance for the future study of
heavy metal pollutants.
Effects of anion on the corrosion behaviors of carbon steel under artificial ...eSAT Journals
Abstract
Rain is one of the main importance issues for atmospheric corrosion problem. Effects of rainfall on corrosion behaviors of carbon steels were investigated using artificial rainfall equipment. Three types of Atmospheric Corrosion Monitoring (ACM) sensors, which consist of Fe-Ag, Zn-Ag, and Al-Ag galvanic couples, were used to illustrate the correlation between the sensors output, Corrosion Rate (CR), and chemical concentration in the rain. The effects of ionic species on the corrosion behaviors were observed by using NaCl, KCl, Na2SO4, NaNO3, and KNO3 as rainfall solutions. The result revealed that the rainfall rate was insensitive to ACM sensors outputs and CRs. In contrast, the chemical species and their concentrations in the rainfall solution significantly affected the ACM outputs and CRs. The corrosivity of the cations (Na+ and K+) is negligible compared to the anions (Cl-, SO42-, NO3-).For a given number of molar concentration, the CRs resulted from the corrosivity of SO4-2anions were higher than that of Cl- and NO3- anions, respectively. According to the empirical data, the CRs is increased and then reach a steady state as the molar concentration is continuously increased. This research also indicates that the ACM sensors outputs of Fe-Ag and Zn-Ag couples are capable of estimating corrosivity of the atmosphere, while the ACM sensor of Al-Agcouple can be used to determine not only the time of wetness but also the typeofchemical species in the environment. The research methods discussed in this paper proves that the CRs are dependent on the atmospheric composition and can be forecasted through ACM sensors.
Effects of anion on the corrosion behaviors of carbon steel under artificial ...eSAT Journals
Abstract
Rain is one of the main importance issues for atmospheric corrosion problem. Effects of rainfall on corrosion behaviors of carbon steels were investigated using artificial rainfall equipment. Three types of Atmospheric Corrosion Monitoring (ACM) sensors, which consist of Fe-Ag, Zn-Ag, and Al-Ag galvanic couples, were used to illustrate the correlation between the sensors output, Corrosion Rate (CR), and chemical concentration in the rain. The effects of ionic species on the corrosion behaviors were observed by using NaCl, KCl, Na2SO4, NaNO3, and KNO3 as rainfall solutions. The result revealed that the rainfall rate was insensitive to ACM sensors outputs and CRs. In contrast, the chemical species and their concentrations in the rainfall solution significantly affected the ACM outputs and CRs. The corrosivity of the cations (Na+ and K+) is negligible compared to the anions (Cl-, SO42-, NO3-).For a given number of molar concentration, the CRs resulted from the corrosivity of SO4-2anions were higher than that of Cl- and NO3- anions, respectively. According to the empirical data, the CRs is increased and then reach a steady state as the molar concentration is continuously increased. This research also indicates that the ACM sensors outputs of Fe-Ag and Zn-Ag couples are capable of estimating corrosivity of the atmosphere, while the ACM sensor of Al-Agcouple can be used to determine not only the time of wetness but also the typeofchemical species in the environment. The research methods discussed in this paper proves that the CRs are dependent on the atmospheric composition and can be forecasted through ACM sensors.
SIMULATION OF ATMOSPHERIC POLLUTANTS DISPERSION IN AN URBAN ENVIRONMENTAM Publications
Interest in air pollution investigation of urban environment due to existence of industrial and commercial activities along with vehicular emission and existence of buildings and streets which setup natural barrier for pollutant dispersion in the urban environment has increased. The air pollution modelling is a multidisciplinary subject when the entire cities are taken under consideration where urban planning and geometries are complex which needs a large software packages to be developed like Operational Street Pollution Model (OSPM), California Line Source model (CALINE series) etc. On overviewing various works it can be summarized that the air pollutant dispersion in urban street canyons and all linked phenomenon such as wind flow, pollutant concentrations, temperature distribution etc. generally depend on wind speed and direction, building heights and density, road width, source and intensity of air pollution, meteorological variables like temperature, humidity etc. A unique and surprising case is observed every time on numerous combinations of these factors. The main aim of this study is to simulate the atmospheric pollutant dispersion for given pollutant like carbon monoxide, sulphur dioxide and nitrogen dioxide and given atmospheric conditions like wind speed and direction. Computational Fluid Dynamics (CFD) simulation for analysing the atmospheric pollutant dispersion is done after natural airflow analysis. Volume rendering is done for variables such as phase 2 volume fraction and velocity with resolution as 250 pixels per inch and transparency as 20%. It can be observed that all the three pollutant namely nitrogen dioxide, sulphur dioxide and carbon monoxide the phase 2 volume fraction changes from 0 to 1. The wind velocity changes from 3.395×10-13 m/s to 1.692×102 m/s. The dispersion of pollutants follow the sequence Sulphur dioxide>Carbon monoxide>Nitrogen dioxide.
An Attempt to Study MoO3-Like TCO Nanolayered Compound in Terms of structural...CrimsonPublishersRDMS
An Attempt to Study MoO3-Like TCO Nanolayered Compound in Terms of structural and Ethanol Sensitivity Application by Boukhachem A* in Crimson Publishers: Peer Reviewed Material Science Journals
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
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About
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Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
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Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
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2. 54 J.F. Ríos-Rojas et al.
1. Introduction
Atmospheric corrosion is the deterioration of a ma-
terial due to electrochemical reactions of its surface
with the constituents of the surrounding atmosphere.
Climatic factors such as temperature, relative humidity
(RH), precipitation and air pollution, determine the
atmospheric corrosion of metallic elements exposed
to such conditions (Oesch, 1996). Air pollutants, to-
gether with moisture, are key elements of atmospheric
corrosion; in consequence, corrosivity depends largely
on the thickness of the humidity layer and the degree
of pollutant deposition rates on the material surface.
When a material is exposed to the atmosphere, the
metal surface will be covered with a thin layer of
water resulting from atmospheric moisture.This layer
dissolvescontaminantsandallowsforthedepositionof
corrosivespeciesonthesurface.Studiesonatmospher-
ic corrosion performed in many cities have concluded
that the nature of atmospheric pollutants and their level
of concentration play an important role on the service
life of different engineering materials (Kucera, 2003;
de la Fuente et al., 2013)
The atmospheric corrosion of steel increases
mainly by the time of wetness, which depends on
meteorological factors such as temperature and RH,
and some pollutants, which tend to significantly
accelerate the attack. In particular, the presence
of sulphur dioxide (SO2) in urban and industrial
atmospheres, and chlorides in areas influenced
by the sea (Mendoza and Corvo, 1999) have been
highlighted. However, in the last decades decreasing
SO2 concentrations have resulted in a new pollution
condition. In tropical climates, the influence of high
temperatures combined with high precipitation and
humidity are observed, because the moisture over
time is very high (Mikhailov et al., 2007; Corvo et
al., 2008).
Some approaches have been used to estimate the
behavior of a material in a given atmosphere, such
as direct measurement of atmospheric corrosion
through the detailed follow up of simple behaviors of
materials of interest, and application of dose-response
functions or damage functions. These have been as-
sociated with the degree of deterioration of similar
materials in equivalent microclimates (Tidblad et al.,
2001) through the application of a function to predict
annual damage caused by atmospheric corrosion.
Damage functions or dose-response equations for
carbon steel corrosion determined in several studies
are shown in Table I.
Table I. Dose-response functions for the atmospheric corrosion of plain carbon steel regarding climatic conditions.
Function Sources
rcorr = 1.77D0.52
SO2
e[0.020RH+fcs(T)]
+ 0.102DCl
0.62
e[0.033RH+0.040T]
rcorr = 1.58[SO2]0.52
e [0.020RH+fcs(T)]
+ 0.102DCl
0.62
e [0.033Rh+0.040T]
where: fcs(T) = 0.15(T–10) when T < 10 °C,
fcs(T) = –0.054(T–10), otherwise
Mikhailov et al., 2004;
Tidblad, 2012
k = 2.72[SO2]0.28
e[0.0171RH+fs(T)]
τ0.575
k = 6.05 [SO2]0.25
e[0.017RH+0.014T–0.000138Rad]
τ0.59
for T > 10 ºC
k = 4.28 [SO2]0.28
e[0.022RH+0.021T–0.000207Rad]
τ0.58
+ 0.121DCl
0.71
e(0.018RH+0.059T)
τ0.62
for T > 10 ºC
where: fs(T) = –0.0467(T-18) when 10 ºC < T < 18 ºC,
fs(T) = 0.0421(T-18) when T > 18 ºC
Mikhailov et al., 2007
ML = 29.1 + {21.7 + 1.39[SO2]0.6
RH60efcs(T) + 1.29Rain[H+
] + 0.593PM10} τ0.6
where: fcs(T) = 0.15(T–10) when T < 10 ºC,
fcs(T) = –0.054(T–10) otherwise
Tidblad et al., 2005
rcorr: corrosion rate in µm yr–1
; k: corrosion rate expressed in terms of a decrease of the metal thickness in µm;
ML: mass loss in g m–2
; T: mean temperature in ºC; RH: relative humidity in %; [SO2]: gaseous SO2 concentration
in µg m–3
, DSO2: SO2 deposition rate in mg m–2
day–1
; DCl: Cl–
deposition rate in mg m–2
day–1
; Rad: total solar
radiation in MJ m–2
year–1
; rain: amount of precipitation in mm; [H+
]: H+
concentration of precipitation in mg L–1
;
PM10: concentration in µg m–3
of particulate matter up to 10 µm in size, and τ: time in years.
3. 55Atmospheric corrosion in Bogotá: Dose-response function
Among some of the most significant results, it is
worthmentioningtheestablishmentofadose-response
function for the corrosion of plain carbon steel due to
the impact of a significant number of environmental
parameters.
1.1 Dose-response function considerations
The statistical methods used in obtaining dose-re-
sponse functions for various metals use multivariate
models, which are based on techniques for estimating
functions with cross-sectional analyses or time series
analyses. Nevertheless, a procedure for using both
transversal and time series data is the longitudinal
data,whoseadvantages(GujaratiandPorter,2009)are:
1. The model has explicitly taken into account the
heterogeneity caused by the atmosphere at each
site, allowing the existence of specific variables
per station.
2. The model provides more data, more variability,
less colinearity among variables, more degrees of
freedom and more efficiency.
3. This model is more suitable for studying the dy-
namics of change, when cross-sectional data per
station are repeated.
4. The model allows detecting and measuring effects
which cannot be observed in cross-sectional data
or time series. For example, the effect of pollution
and atmospheric parameters on corrosion can be
better studied because the model includes the
variations of other variables.
5. Allows identifying factors other than atmospheric
parameters of a region in a single equation.
Longitudinal data can be estimated using meth-
ods such as the pooled ordinary least squares (OLS)
model, the fixed effects least squares dummy variable
(LSDV) model, the fixed effects within-group or the
random effects model.
The effect of atmospheric variables and pollutants
on the corrosion rate is analyzed by the dose-response
function represented by Eq. (1):
rcorr,it = f (RHit, Tit, DSO2it
, DPMit, τ) (1)
where DPM is the particulate matter (PM) deposition
in mg m–2
day–1
and τ is the exposure time (months);
i corresponds to the i-th corrosion station and t is the
time period in which data were collected.
According to the dose-response functions re-
ported by Mikhailov (2001) and Mikhailov et al.
(2004, 2007) and using the methodology of longi-
tudinal data, functions for any city are represented
by Eq. (2):
rcorr,it = β1DSO2it
+ β2DPMit
+ β3RHit
+ β4Titt
+ β5τit + α1 +∑i=2
n+1
α1Di + µit
(2)
where Di is a dummy variable or a dichotomous vari-
able which is used to take into account the specified
characteristics of each station, and n is the number
of corrosion stations. Eq. (2) shows ML as a linear
function of an asset of explanatory variables. On the
other hand, dichotomous variables are introduced
in this equation in order to use longitudinal data
(Eq. 3).
rcorr,it = β0[DSO2it
β1][DPMit
β2]exp(β3RHit + β4Tit)
[τit
β5] + µit
(3)
Eqs. (2) and (3) represent deviations of the cor-
rosion rate between the experimental and estimated
values from the dose-response function.
Eq. (3) assumes that the variables included in the
model affect similarly carbon steel throughout the
city. This equation is in accordance with the studies
of Mikhailov, but also assumes that there is a statis-
tically homogeneous behavior in the different sites of
the region. For the above two equations, parameters
β1, β2, β3, β4 and β5 measure the variables effects on
the corrosion rate.
The main difference between these two equations
is that Eq. (2) assumes a linear relationship, while Eq.
(3) assumes an exponential relationship.
1.2 Site
Colombia is an equatorial country with the Andes
mountain range crossing the west side from south to
north and with a wide geographic diversity, including
savannas, mountains from the sea level to perpetual
snow peaks, desserts and forests.
Bogotá city, the capital of Colombia and one of
the most air-polluted cities in the region, is located
in the center of the country in an intertropical zone
2600 masl (Franco et al., 2015). It shows concentra-
tions of pollutants such as sulfur oxides (SOx), PM,
nitrogen oxides (NOx), and others, distributed within
urban and periurban areas according to socio-eco-
nomic activities. These variables along with the
4. 56 J.F. Ríos-Rojas et al.
climatic features of the city converge in degradation
processes of materials exposed to the atmosphere.
A former research reported that atmospheric
corrosion of carbon steel in Bogotá was less than
50 μmyr–1
(400 g m–2
yr–1
) according to meteorological
parameters and pollutant concentration data collect-
ed by the city network of environmental assessment
during several years, and there was mass loss of carbon
steel after one year of exposure (Ríos Rojas et al.,
2015). Nevertheless, a damage function of carbon steel
corrosion from measurements of standard specimens
was not found.
The aim of this study was to determine the be-
havior of plain carbon steel in Bogotá from mea-
surements in different exposure sites, searching for
an annual dose-response function for this material.
Therefore, the current study was oriented to assess
general atmospheric corrosion of plain carbon steel in
Bogotá city from the exposure of samples in specific
points of interest, locating racks according to the
ASTM G-50 standard.
2. Experimental procedure and materials
CommercialAISI-SAE 1006 carbon steel plates (100
× 150 × 1.6 mm) were used to evaluate corrosion
rates.The composition of steel was 0.061% C, 0.015%
Si, 0.180% Mn, 0.008% S, 0.001% P, 0.019% Cu,
0.040% Al, 0.020% Cr, 0.010% Ni. The plate surface
was initially prepared by degreasing with ethanol
and drying with an air jet. Before testing, the plates
were weighed on an analytical balance of 0.1 mg of
resolution; the initial mass was recorded and then they
were stored in a desiccator prior to exposure.The eval-
uation of carbon steel plates was then carried out by
triplicate over 12 months. Specimens were withdrawn
after 3, 6, 9 and 12 months, between February 2012
and February 2013. Likewise, the values of RH and
temperature were recorded continuously at each site
using a thermohygrometer (42270 Extech) (recording
three points per hour).
Deposition rates of SO2 and particulate matter
(PM) were determined each three months using
passive samplers, which allow quantification of cu-
mulative air pollutant deposited on. The deposition
rate of SO2 at each site was determined by the lead
dioxide technique, according to standard ASTM
D-2010 (ASTM_D2010, 2004). These candles were
exposed for three months, then removed and re-
placed with other candles. The deposition rate of PM
was determined in triplicate from petri glass dishes
located into a louvered enclosure. After exposure,
the disk was washed and the amount of deposited
material was evaluated, which allows calculating
the deposition rate of PM. Both candles and discs
were installed in a rectangular louvered enclosure
to provide maximum protection from rain.
2.1 Exposure sites
Carbon steel plates were exposed in eight different
sites across Bogotá as it is shown in Figure 1. The
exposure angle was 45º from the horizontal and
with the upper surface facing south according to
ASTM G50 (ASTM_G50, 2003). The exposure
sites were selected based on the level of pollutants
and meteorological parameters reported by the
city network of environmental assessment, and
located according to standards for sampling total
sulfation activity and chloride deposition from the
atmosphere, as well as siting criteria for ambient air
monitoring (ASTM_G140, 2002; ASTM_D2010,
2004; EPA, 2006). These sites were distributed as
follows: one in the north (Calle 170), one in the
northwest (Suba-Corpas), one in the east (Can-
delaria), one in the west (Federman), two in the
southwest (Fontibón,Autopista-Sur), and two in the
south (Restrepo and USME). The higher density of
stations in the west and south was due to the higher
concentration of pollutants in those areas.
N
S
EW
Suba Corpas
Suba Calle 170
Federman
USME
Restrepo
Candelaria centro
Fontibon
Kennedy
Autopista Sur
Fig. 1. Location of the stations across the city.
5. 57Atmospheric corrosion in Bogotá: Dose-response function
3. Results and discussion
3.1 Meteorological variables
Bogotá is located on a very high plateau, surrounded
by a mountain range that influences its precipitation
regime. Bogotá´s rainy seasons run from March
to May and from September to November. Mete-
orological data of the city of Bogotá are shown in
Figure 2.
Figure 2a, b shows the mean temperature in the
period 1998-2011 and the average temperature in
2012 (year of exposure). The average temperature
was almost constant during the last years, which is
observed in the annual temperature value in Figure 2a.
The recorded values of mean temperature ranged from
12 ºC to 15 ºC, being March,April, May, October and
November the months with highest values (Fig. 2b).
A slight increase in temperature is recorded during
the last quarter of the year. Temperature is distrib-
uted over the year in a slightly bimodal manner,
associated with the precipitation regime. In addition,
temperature inversion is normally present from
December to January due to winds of low intensity
causing frost. Throughout 2012, the maximum abso-
lute values of temperature exceeded slightly 25 ºC,
especially in the months of January, February, March,
April, October, November and December, and the
absolute minimum recorded was 3.2 ºC in January
(RMCAB, 2013).
Precipitation in Bogotá could range from 500 to
1000 mm yr–1
, being highest in the eastern part of
the city. Figure 2c shows the historical series of pre-
cipitation recorded from August 1997 up to 2012. A
significant increase in the cumulative precipitation is
observed, reaching greater values between late 2010
and early 2011, when Colombia suffered natural disas-
ters resulting from high precipitation rates. Bogotá has
less than 200 days of precipitation per year. January
and February are the driest months and October and
November the most humid (Fig. 2d). The behavior
of precipitation throughout the year corresponds to a
a)
15
1000
82
80
78
76
74
72
70
68
66
800
600
400
14
13
12
1998
Time (year)
Temperature(ºC)
b)
15
14
Average 1998-2011
Average 2012
13
Temperature(ºC)
Relativehumidity(%)
Precipitation(mm)
2000 2002 2004 2006 2008 2010 2012 1 2 3 4 5 6
Time (months)
7 8 9 10 11 12
1998
Time (year)
2000 2002 2004 2006 2008 2010 2012
1998
Time (year)
2000 2002 2004 2006 2008 2010 2012
c)
e)
d)
100
50
Average 1998-2011
Average 2012
0
Precipitation(mm)
1 2 3 4 5 6
Time (months)
7 8 9 10 11 12
f)75
70
65
Average 1998-2011
Average 2012
60
Relativehumidity(%)
1 2 3 4 5 6
Time (months)
7 8 9 10 11 12
Fig. 2. Meteorological parameters in Bogotá.Annual average values (a, c, and e), and monthly
average values for 2012 and previous years (b, d, and f).
6. 58 J.F. Ríos-Rojas et al.
bimodal distribution, from March to May and October
to November.
The registered annual and monthly average RHs
between 2006 and 2012 are shown in Figures 2e, f,
respectively. The average RH slightly decreases
during the last years (Fig. 2e). The RH mean values
recorded range between 65 and 80%. The higher val-
ue registered in 2011 is associated with the increase
of precipitation during that year. March, April, May,
October, November and December have the highest
RH, which corresponds to the months of the year
with highest precipitation.
3.2 Pollution
The air consists of several chemical components such
as N2, O2, H2O, CO2, Ar, Ne, He, H2, and CH4, but
anthropogenic activities affect such basic composi-
tion. Burning fossil fuels and industrialization are
factors that have influenced air composition due to
the generation of pollutants such as volatile organic
compounds (VOC), NOX, SO2, CO, and PM.
Bogotá city is among the most polluted metropolis
in Latin America, after Mexico City and Santiago.
Nevertheless, Bogotá does not suffer the rigorous
consequences of this fact, due to its topographical dis-
tribution and meteorological variables that produce
pollutants dispersion. The most critical air pollutant
in the city is PM10. Studies report that mobile sources
contribute very significantly to the emissions of this
pollutant (Behrentz, 2009); also, that the chemical
composition of PM has an ion contribution where
sulfates and nitrates are the anions species making
the greatest contribution to the composition of PM10
in Bogotá. According to Figure 3a, a significant
reduction of PM in recent years contrasts with its
relevant increase from 2004 to 2007.
SO2 occurs mainly due to the use of fossil fuels
with sulfur content such as coal, diesel or gasoline
used in industries and automobiles. Industrial sources
contribute about 60% of PM emissions and 70% of
the SOx emissions into the atmosphere of Bogotá
(Rojas, 2007). According to the local environmental
authority, PM10 and SO2 concentrations decreased
during the last years due to the control of permissible
maximum levels in the industrial sector and mobile
sources (such as public transportation systems).
Figure 3a, b shows the effects of mandatory lower
sulfur concentrations in fuel. These figures confirm
the idea that the city is following the general trend
of decreasing pollution in many capitals worldwide
(Kucera, 2003).
3.3 Corrosion rate
Meteorological behavior at the test sites is shown in
Figure 4. Figure 5 shows the corresponding pollutants
deposition for the same period of time.
Temperature is homogeneous and almost constant
within the urban area (close to 15 ºC), considering
the topographic features (a plain area). The USME
station, located south of the city within the periurban
area, and at a higher elevation than the other sites, has
the lowest value of average temperature. This station
in turn shows the highest value of RH. Average RH
values are usually higher than 60% in all sites, with
80
70
60
50
Particulatematter10(µg•m–3
)
40
2000 2004
Time (year)
2008 2012
40
30
20
10
Sulfurdioxide,SO2(µg•m–3
)
0
2000 2004
Time (year)
2008 2012
Fig. 3. Annual atmospheric pollution in Bogotá. (a) Particulate
matter. (b) Sulfur dioxide.
7. 59Atmospheric corrosion in Bogotá: Dose-response function
higher values in the stations located south and north
of the city.
The average deposition rate of SO2 is less than 10
mg m–2
day–1
, which is in accordance with the atmo-
spheric concentrations shown above. It was found
that Autopista-Sur and Fontibón stations, located in
semi-industrial areas, showed the highest values of
the SO2 deposition rate due to industrial activities and
high vehicle traffic. In accordance with the SO2 trend,
PM deposition data are homogeneous and the stations
located in the west part of the city show higher values
(mainly the Autopista-Sur station).
The corrosion rates of carbon steel in the exposure
sites are shown in Figure 6. The corrosion rate was in
very good agreement with the behavior of pollutants,
mainly with the SO2 level; however, the magnitude
of rcorr is not strictly proportional to that of the SO2
deposition. The corrosion rate was almost constant
in the test sites having low SO2 and PM depositions,
suggesting that carbon steel does not produce a pro-
tective corrosion layer in these sites. Candelaria and
USME generally show corrosion rate values below
10 µm yr–1
, closely associated to the low level of
pollutants. Nevertheless, the USME station shows a
greater value than the Candelaria station, associated
with higher RH. The corrosion rate throughout the
16
a)
15
14
13
12
0 3
Suba-Corpas Calle 170 Fontibón Federman
Candelaria Autopista Sur Restrepo Usme
6
Exposure time (months)
Temperature(ºC)
9 12
90
b)
80
70
60
50
0 3 6
Exposure time (months)
Relativehumidity(%)
9 12
Fig. 4. Meteorological features of the test sites.
8
a)
6
4
2
0
0 3
Suba-Corpas Calle 170 Fontibón Federman
Candelaria Autopista Sur Restrepo Usme
6
Exposure time (months)
SO2(mg•m–2
•day–1
)
9 12
200
b)
160
140
120
180
100
40
20
80
60
0
0 3 6
Exposure time (months)
Particulatematter(mg•m–2
•day–1
)
9 12
Fig. 5. Pollutants deposition rates at the test sites.
8. 60 J.F. Ríos-Rojas et al.
exposure time only decreases clearly at Auto-
pista-Sur, which has the greatest pollution levels and
average RH below 70%. A similar behavior for the
corrosion rate was obtained in Restrepo, which has an
equal value of RH but less pollutant deposition rates.
It may be considered that the highest SO2 deposition
registered in this study leads to the formation of a
protective corrosion product on carbon steel surface
due to a more compact and thicker layer, which has
been reported by other researchers for low and me-
dium contents of SO2 (Morcillo et al., 1998).
3.4 Dose-response function
Preliminary analyses were often made with the use
of PM deposition data, which increased the goodness
of fit or R2
; however, being strongly correlated to the
SO2 concentration and included in the equations, PM
produced an underestimation of the true effect of SO2,
whichiswhyitwasfinallyexcludedfromthestatistical
analysis.Ontheotherhand,Eq.(3)gaveabetterestima-
tion than Eq. (2) of the corrosion rates, including both
best-fit and individual significance of the parameters.
Accordingly, the annual dose-response function
of carbon steel in Bogotá city, in agreement with the
experimental data, is shown in Eq. (4):
Fig. 6. Corrosion rate throughout the exposure time.
80
60
50
70
40
30
20
10
0
0 3
Suba-Corpas Calle 170
Fontibón Federman
Candelaria Autopista sur
Restrepo Usme
6
Exposure time (months)
Corrosionrate(µg•year–1
)
9 12
rcorr,it = 0.071[DSO2it
0.37
]exp(0.045 RH + 0.14 T)
(4)
Eq. (4) allows for calculating the annual corro-
sion rate as a function of the main climatic variables.
The coefficient of determination or prediction
capacity value (R2
) is 0.67, indicating a proper
goodness of fit, and the model is globally significant
because the value of the statistic F(4.27) = 6.81; that
is, the corrosion rate of carbon steel is adequately
explained by the change in the explanatory variables
(RH, T, SO2).
All climatological parameters have a positive
relationship with the metal corrosion rate according
to this equation. The function proves possible nonlin-
ear effects of independent variables on atmospheric
corrosion (primarily SO2, RH and T).
4. Conclusions
An average atmospheric corrosivity value on plain
carbon steel could be ranged between 5 µm yr–1
and
35 µm yr–1
in Bogotá. The highest values are general-
ly associated with higher SO2 levels, associated with
regions of higher anthropogenic activity.
Environments with higher level of pollutants
(mainly SO2) and an average relative humidity
below 70% have a greater tendency to form a pro-
tective corrosion layer after one year of exposure.
This behavior is most evident in sites with medium
SO2 content.
A dose-response function of RH, T and SO2
deposition, to determine the corrosion rate of plain
carbon steel for the first year of exposure, has been
derived. The obtained annual dose-response function
provided a valid method to estimate the corrosion
rate of carbon steel during the first year of exposure
to the atmosphere of Bogotá.
Acknowledgements
The authors acknowledge Universidad Antonio
Nariño for the support given during the devel-
opment of project No. 2010257. Likewise, the
authors express their gratitude to the Secretaría
de Ambiente de Bogotá (Environment Secretar-
iat of Bogotá) for providing meteorological and
pollutants data used in this paper. The authors
also acknowledge the following institutions and
companies for allowing them to locate stations in
their facilities: Hilandería Fontibón, Almacenes
MAKRO and CIEDI School.
9. 61Atmospheric corrosion in Bogotá: Dose-response function
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