60 research outputs found
Phytoremediation of Soils Contaminated with Heavy Metals Resulting from Acidic Sludge of Eshtehard Industrial Town using Native Pasture Plants
Phytoremediation of heavy metals is considered as an inexpensive and practical technique for purifying contaminated soil, especially when eco-friendly native pasture plants of the contaminated area are used. In this study, heavy metals in soil including Cr, Zn, Cd, Pb, and Ni and native pasture plants around Eshtehard industrial town, which were contaminated due to the entry of acidic sludge, were examined. In this regard, the hyperaccumulation and phytostabilization potential of the plants in the study area were investigated. Accordingly, A.tenuifolia in Cd, Pb and Ni, C.persica in Zn, C. arenarius in Ni, P. piptostigma in Cr and Zn, B. tectorum in Cd and Zn, S. hohenackeriana in Cr, Pb and Cd, P.aucheri in Zn, and P. harmala L in Pb and Ni. Species with stabilizing potential include A. tenuifolia In Cd and Ni, N. persica in Zn, A.tauschii and B. tectorum in Ni, P.aucheri and P.harmala in Pb. Hyperaccumulating plants can be disposed of easily just like industrial wastes with heavy metals. Plants with stabilizing capacity can prevent the spread of heavy metal contamination to uncontaminated areas like the surrounding farms in addition to providing visual beauty for the region. Keywords: acidic sludge, heavy metals, phytoremediation, Eshtehard industrial town
Phytoremediation of Soils Contaminated with Heavy Metals Resulting from Acidic Sludge of Eshtehard Industrial Town using Native Pasture Plants
Phytoremediation of heavy metals is considered as an inexpensive and practical technique for purifying contaminated soil, especially when eco-friendly native pasture plants of the contaminated area are used. In this study, heavy metals in soil including Cr, Zn, Cd, Pb, and Ni and native pasture plants around Eshtehard industrial town, which were contaminated due to the entry of acidic sludge, were examined. In this regard, the hyperaccumulation and phytostabilization potential of the plants in the study area were investigated. Accordingly, A.tenuifolia in Cd, Pb and Ni, C.persica in Zn, C. arenarius in Ni, P. piptostigma in Cr and Zn, B. tectorum in Cd and Zn, S. hohenackeriana in Cr, Pb and Cd, P.aucheri in Zn, and P. harmala L in Pb and Ni. Species with stabilizing potential include A. tenuifolia In Cd and Ni, N. persica in Zn, A.tauschii and B. tectorum in Ni, P.aucheri and P.harmala in Pb. Hyperaccumulating plants can be disposed of easily just like industrial wastes with heavy metals. Plants with stabilizing capacity can prevent the spread of heavy metal contamination to uncontaminated areas like the surrounding farms in addition to providing visual beauty for the region. Keywords: acidic sludge, heavy metals, phytoremediation, Eshtehard industrial tow
Investigation of Corrosion Behavior for Copper-Based Shape Memory Alloys in different Media
Copper based shape memory materials was interesting group of metal alloys that have a widespread potential in medical and industrial application due to their characteristics ,the possibility of exhibiting shape memory behavior and lower cost. In this research the alloy (Cu-(15-40) wt%Zn-6wt.%Al) has been prepared by powder metallurgy technique Zn element (15, 20, 25, 30, 35, 40 wt%Zn) and fixed percentage of Al content which is 6.wt%Al then aluminum replaced by (Si, Sn, Ni )element at fixed percentage of 6wt.%, in order to study the effect of these elements on SMA. After samples preparation examination were done by using XRD, SEM technique, DSC, Vickers hardness, Archimedes method to measure the porosity percentage and corrosion rate in different solutions (HCl, NaOH and SEAWATER).The XRD and microstructure results show that all samples with and without additives consist of two phases (β-phase) and (α-phase) at room temperature and the addition of alloying elements in these percentages does not have effect on present phases. the hardness increased with zinc content because the formation of intermetallic compound of CuZn that responsible to hardness while The addition of Si ,Sn and Ni leads to lower the hardness than aluminum. The bulk density increased with the alloys without addition alloying elements(Si, Ni and Sn ) while apparent porosity decreased with it the reason for this phenomenon due to the characterization of alloying elements that addition to the alloy. From the results of corrosion test can be show the alloy with 35wt% Zn have the higher corrosion resistance in all media (HCl, NaOH and sea water) and the addition of alloying element lead to improve the corrosion resistance. Finally, it is observed that the Copper base shape memory alloys with these types of additives are suitable for use in different application
Physical, chemical and biological quality assessment of aqueduct (Qanat) water for drinking, agriculture and irrigation of urban green spaces
BACKGROUND AND OBJECTIVES: The aqueduct is one of the most complex and amazing inventions of human history, created to meet the most vital needs of human society in arid and semiarid regions areas. If aqueducts are properly maintained, reconstructed, and restored, they can be valuable water supply system from ground water resources. The quality of the water in these sources will have a direct impact on the consumer of its consumption, so it seems necessary to check the water quality of these sources.METHODS: This study investigated the state of five aqueducts in Tehran using parameters such as calcium, magnesium, phosphate, sulfate, turbidity, total hardness, nitrate, alkalinity, electrical conductivity, Biochemical Oxygen Demand, Chemical Oxygen Demand, total coliform and fecal coliform. Then the obtained values were compared with the permissible limits of the World Health Organization and the national standard of Iran. The data was analyzed using SPSS26 software and a one-sample t-test.FINDINGS: The results of water quality during a one-year survey period showed that the parameters of alkalinity, electrical conductivity, total dissolved solids, sulfate, and nitrate were below the maximum desirable and permissible standards of the national standard of Iran and the World Health Organization, and therefore will not create any restrictions for drinking and agricultural use. Total hardness, phosphate, turbidity, calcium, magnesium, and chlorine have discrepancies with the national standards of Iran and the World Health Organization and these components must be adjusted for use. According to the one-sample t-test, there was a significant difference between the average and the permissible values of all parameters except magnesium at the 95% confidence level. All aqueducts except the America aqueduct had levels of fecal coliform that were higher than the maximum allowed by the environmental standards therefore, before using the aqueduct, it must be purified to control the environmental standards.. However, the total coliform, Biochemical Oxygen Demand, Chemical Oxygen Demand levels were not a problem. In addition, the water quality of these sources was placed in a group (C3S1) based on the Wilcox diagram.CONCLUSION: The physical and chemical analysis of the studied aqueduct water showed that the water quality is suitable for the irrigation of green spaces and salt-resistant plants. The biological characteristics of the studied aqueduct water also revealed that these sources were polluted by domestic and industrial effluents. This issue will only grow worse with time, as the amount of rainwater decreases and the amount of pollution in the underground water sources increases
Measurement of the top quark mass using events with a single reconstructed top quark in pp collisions at root s=13 TeV
Abstract:A measurement of the top quark mass is performed using a data sample en-riched with single top quark events produced in thetchannel. The study is based on proton-proton collision data, corresponding to an integrated luminosity of 35.9 fb−1, recorded at√s= 13TeV by the CMS experiment at the LHC in 2016. Candidate events are selectedby requiring an isolated high-momentum lepton (muon or electron) and exactly two jets,of which one is identified as originating from a bottom quark. Multivariate discriminantsare designed to separate the signal from the background. Optimized thresholds are placedon the discriminant outputs to obtain an event sample with high signal purity. The topquark mass is found to be172.13+0.76−0.77GeV, where the uncertainty includes both the sta-tistical and systematic components, reaching sub-GeV precision for the first time in thisevent topology. The masses of the top quark and antiquark are also determined separatelyusing the lepton charge in the final state, from which the mass ratio and difference aredetermined to be0.9952+0.0079−0.0104and0.83+1.79−1.35GeV, respectively. The results are consistentwithCPTinvariance
Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions. Funding: Bill & Melinda Gates Foundation
NUMERICAL STUDY ON PERFORMANCE OF A SIX-STORY HYBRID STRUCTURE WITH STEEL MOMENT FRAME SYSTEM AND USING CLT AS SHEAR WALL AND FLOOR PANEL
Recently, researchers have introduced CLT (Cross Laminated Timber), a kind of engineered wood product that is one of the most suitable construction materials for green building development for the future cities. In the design steel-timber hybrid structure presented in this study, steel is used for the intermediate moment resisting frame of the building and CLT are used as floor panels and shear walls. Therefore, the lateral load-resisting system of the hybrid structure in this study is the dual system of steel intermediate moment resisting frame and CLT shear wall. In order to investigate the structural performance of the above-mentioned system, a sample 6 stories building are considered to be constructed using two types of structural systems were designed using ETABS software; 1- a steel intermediate moment resisting frame with composite concrete-steel floor, and, 2- dual steel intermediate moment resisting frame plus CLT shear walls with timber-steel floor using CLT horizontal panels. Then, FEM model of each of structural frame two types was analyzed using pushover method by ABAQUS software. The behavior of the two type 6-story frame systems were compared. By comparing the weight of Structure with the two types of lateral load-resisting system, it was concluded that the total weight of the building reduced by %22.01 in the structure with a dual system of steel intermediate moment resisting frame and CLT shear wall and composite timber-steel floors, compared to the structure with the steel intermediate moment resisting frame system and composite concrete-steel floors. Comparison of the results concludes that the application of possible substitution of CLT panels instead of steel and concrete common materials of structural members results in light weight structure with acceptable seismic behavior. Furthermore, development of hybrid timber-steel construction can provide buildings with less greenhouse, environmental, and noise pollution for producing materials and building structure, lower energy consumption, less weight, good seismic behavior, fast construction speed, and renewable resource capability
Optimization of Nitrogen Removal from Synthetic Wastewater by Eliminating Nitrification Step of a Fixed-Film Bed Reactor
Background and Objectives: In order to optimize wastewater nitrogen removal and to reduce the problems of entering nutrients in final receptors, for example, a lake, partial nitrification, as a novel nitrogen removal method, was studied.
Materials and Methods: The efficiency of simultaneous nitrification and denitrification (SND) in partial nitrification through nitrification/denitrification in fixed-film reactor was surveyed. In this process, ammonium was converted to nitrite by ammonium oxidizing bacteria (AOB) but the activity of nitrite oxidizing bacteria (NOB) was limited at low dissolved oxygen (DO) level. The inflection points of oxidation-reduction potential (ORP) profile were used as the indicators of process optimization.
Results: This research showed that in period 2 at fixed DO level of 0.5 mg/L, nitrite accumulation rate (NAR) was higher than period 1 in which DO was declined from 1 to 0.5 mg/L. In contrast to period 1, SND efficiency was reduced in period 2. In period 3, by increment of the carbon to nitrogen ratio (C/N) to 12.5, NAR increased to 71.4 % and SND efficiency increased to 96.7%. In the long term analysis of proposed method, SND efficiency was, at least, 90%.
Conclusion: Proper C/N ratio and minimum DO level resulted in higher nitrogen removal efficiencies than the operation in which DO was decreased during aerobic phase. By using a fixed-film reactor and without considering an anoxic step, at DO level of 0.5 mg/L, maximum SND efficiency and maximum NAR would be achieved. 
Role of Saline Water in Removal of Heavy Elements from Industrial Wastewaters
Flocculation processes during estuarine mixing can reduce the elemental
concentrations of river water. In the present investigation, natural
flocculation processes concept is used to reduce the elemental contents
of industrial wastewater. For this purpose, various amounts of saline
water were added to an artificial industrial wastewater with known
concentrations of heavy metals. The results of investigation show that
in the salinity of 0.9‰, percentage of elemental flocculation
occurs in the order of: Ni (95.4%) > Pb (87.6%) > Zn (85%) >
Mn (56.25%) > Cu (14.4%). Flocculation of Cu is insignificant at
lower salinities. Though higher removal of heavy metals is obtained at
greater salinities but due to the environmental limitations, we propose
salinity of 0.9‰. Use of seawater to flocculate heavy metals can
greatly reduce the costs associated with the purification of wastewater
treatment
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