Refine search
Results 231-240 of 63,319
Hematological responses of Goldfish (Carassiusauratus) to different acute concentrations of Silver Sulfate as a toxicant Full text
2015
Abarghoei, Safoura | Hedayati, Seyed Aliakbar | Ghafari Farsani, Hamed | Gerami, Mohammad Hasan
This study aimed to evaluate the efficacy of silver sulfate (AgSO4) as a toxicant in goldfish (Carassiusauratus). One hundred and forty-seven live specimens of C. auratus were obtained and exposed to 1, 10, 100, 500, 1000 and 2000 ppm of AgSO4for 96 hours. There was one control group (no AgSO4) and three replicates. The physicochemical properties of water and the following parameters were constant: pH: 7.56±0.45 (TS1); temperature: 19±1°C; hardness: 293±2.35 ppm and dissolved oxygen: 8.80 ±0.06 mg L-1 (DO-5510). LC1, LC10, LC30, LC50, LC70, LC90 and LC99 were calculated in 24, 48, 72 and 96 hours. For assessing the impact ofAgSO4 on physiological responses of goldfish hematological indices, blood glucose and cortisol levels were measured. Results showed that LC50 96-h of AgSO4 for goldfish was 687.81 ppm. In addition, the use of AgSO4induces a significant decrease in MCHE after 48 hours, MCV and MCH after 96 hours and lymphocyte after 96 hours in contrast to the control group (P<0.05). Furthermore, increased lymphocyte was significant after 24 hours exposure (P<0.05). In addition, glucose increased significantly at P<0.05 with time increase24 hours after experiment but this (). In conclusion, the study showed that acute toxicity of AgSO4induced hematological alterations in goldfish and offers a tool for the evaluation oftoxicity-derived alterations.
Show more [+] Less [-]Development of a new low-cost procedure for wind farm maintenance with a view to decrease soil pollution Full text
2015
Costa, Angel M. | Fraguela, Feliciano | Orosa, Jos&eacute; A. | Roshan, Gholamreza
The purpose of this article is to present the development of a wind farm, with a condition monitoring system (CMS) based on control charts as the algorithm, centred on a new index, to prevent soil pollution by oil spills in wind farms. To this end, temperature sensors can be considered as one of the more significant sensors to be employed in this study, because the information obtained with regard to anemometers and electrical power output counters can be employed by the control system. As a result, among the other variables, oil temperatures sampled in multipliers used in the wind turbines of a real wind farm were employed. Statistical analyzes were developed and the relationship between wind farm maintenance (usually related to wind farm oil spills) and oil temperature was obtained. Furthermore, a practical case study, centered in the statistical process control, based on the low-cost sample variable was developed and showed that this new procedure would improve deficiencies in the maintenance process, thus, reducing the failure detection time under low sensor cost, as also the related soil pollution.
Show more [+] Less [-]Natural radioactivity in virgin and agricultural soil and its environmental implications in Sungai Petani, Kedah, Malaysia Full text
2015
Ahmad, Nisar | Jaafar, Mohamad | Alsaffar, Mohammed
A study on natural radioactivity in virgin and agricultural soil samples collected from Sungai Petani was conducted using high-purity germanium. The mean activity concentrations of 226Ra, 232Th, and 40K in virgin soils were 51.06±5.83, 78.44±6.42, and 125.66±7.26 Bq kg−1, respectively, while those in agricultural soils were 80.63±5.78, 116.87±7.87, and 200.66±18.24 Bq kg−1, respectively. The corresponding activity concentrations in agricultural soils were higher than those in virgin soils and those reported for other countries of the world. The average values of radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), outdoor annual effective doses (Eout), and indoor annual effective doses (Ein) in agricultural soils were 258.38 Ba kg−1, 0.708, 0.925, 0.162 mSv y−1, and 0.669 mSv y−1, respectively. The average values of outdoor external dose (Dout) and indoor absorbed dose (Din) rate in agricultural soils were 116.04 and 218.46 nGy h−1, respectively, which were higher than the permissible limit. Soil with Hex and Hin less than unity are suitable for use as building materials and in agriculture.
Show more [+] Less [-]Assessment of indoor cancer linked to accumulated radiation dose from different types of television sets in dwellings Full text
2015
Njinga, Raymond | Mamman, Sameul
Exposure to radiation from different types of television sets was measured to ascertain the levels of hazards posed to the human biological system. Measurement of the annual radiation dose hazards was performed using a halogen-quenched GM tube with thin mica end window having a density of 1.5 mg/cm2, effective window diameter of 0.360 inch and side wall of 0.012 inch thick. The GM tube was placed for 180 minutes and the sensor faced the screens of the various TV sets, one meter apart. The annual radiation dose ranged from 0.012 ± 0.006 mSv/yr for plasma-SONY to 0.13 ± 0.012 mSv/yr for SHARP and SAMSUNG 24 inch TV sets, containing cathode ray tubes. The annual doses from the 15 and 24 inch-LG TVs (manufactured with cathode ray tubes) were relatively low, with values of 0.031 ± 0.017 and 0.035 ± 0.005 mSv/yr, respectively. The 21 inch THERMOCOOL and PROTECH (with cathode ray tubes), produced annual doses of 0.110 ± 0.052 Sv/yr and 0.063 ± 0.002 mSv/yr, respectively. This provides an insight into the amount of radiation generated by different TV sets in households, on an annual basis. After some years of exposure to TV radiation, health complications such as carcinogenesis or other adverse cellular events may occur, due to cumulated (but does not always) doses which may result in DNA damage, to the human biological system.
Show more [+] Less [-]Environmental policy and management of freshwater resources in the Haraz-Ghareh Su Basin in comparison to other Caspian sub basins Full text
2015
Hedayati Aghmashhadi, Amir | Jafari, Hamidreza | Mehrdadi, Naser | Fahmi, Hedayat | Farshchi, Parvin
Haraz-Ghareh Su is one of the seven sub-basins of the Caspian basin, located on the southern shores of the Caspian Sea, and as such, is in danger of water crisis due to absence of proper systematic policy and strategy. In this study, the pressure factors on the Haraz-Ghareh Su water resources were identified using DPSIR model. Then, the pressure parameters on the freshwater resources in the Caspian Basin were scored and prioritized into two categories: human and non-human criteria and eight sub-criteria with the help of questionnaires (the opinion of 36 specialists in environmental planning and management, as well as the use of FANP). Thereafter, the data layers were processed with the help of IDRISI software, and eventually, the data were overlaid in the ArcGIS and the final plan was made. The findings of the study shows that, among 8 effective sub-criteria on the environmental planning and management of the freshwater resources in the Haraz-Ghareh Su Basin, agricultural water consumption with 0.243 score points and dam-making with 0.039 score points are considered most and least important sub-criteria, respectively. Consequently, after the compilation and scoring of sub-basins of the Caspian basin, it appears that the sub-basin of Haraz-ghare Su with 0.158627 points had the worst situation in terms of the planning and management of freshwater resources in the Caspian basin. In order to decrease the pressure on the freshwater resources in the Haraz-Ghareh Su Basin, the formulation of long-term policy and strategy in this basin seems to be essential.
Show more [+] Less [-]Evaluation of kinetics and adsorption isotherms for the Elimination of Pb(II) from aqueous solutions using Aloe barbadensis Miller Leaf Powder Full text
2015
Malik, R | Lata, Suman | Singhal, Sushila
An adsorbent was developed from matured leaves of the Aloe barbadensis miller plant for removing Pb(II) from aqueous solutions. Adsorption was carried out in a batch process with several different concentrations of Pb(II) by varying amount of adsorbent, pH, agitation time and temperature. The uptake of the metal was initially very fast, but gradually slowed down indicating penetration into the interior of the adsorbent particles. The experimental data closely followed both Langmuir and Freundlich isotherms. A small amount of the adsorbent (1 g/50ml) could remove as much as 86% of Pb(II) in 35 min from a solution of concentration 0.3 mg/50ml at 25°C. The adsorption continuously increased in the pH range of 2.0–5.0, beyond which the adsorption could decrease up to pH 7.0 when the adsorption could not be carried out due to precipitation of the metal. The adsorption was exothermic at ambient temperature and computation of the parameters, ΔH, ΔS and ΔG, which indicated the interactions to be thermodynamically favorable.
Show more [+] Less [-]Application of AERMOD to local scale diffusion and dispersion modeling of air pollutants from cement factory stacks (Case study: Abyek Cement Factory) Full text
2015
Noorpoor, Alireza | Rahman, H. R.
Today, the cement industry is one of the major air polluting industries in the world. Hence, in this study, owing to the importance and role of contaminants from the plant, an appraisal of the emission contributions in addition to other factors have been discussed. There are several reasons behind the importance of modeling air pollutants. First, the assessment of standards for air pollution, and the fact that the measurement points are limited. Furthermore, in all industrial areas, measurement and installation of assessment and monitoring stations are not feasible. The AERMOD model is a dispersion steady state model which is utilized to determine the concentration of various pollutants in different areas from urban and rural, flat and rough, shallow diffusion in height, from standpoint and different shallow sources. In this model, it is assumed that the dispersion of concentration in Stable Boundary Layer (SBL) in two horizontal and vertical directions are similar to that of horizontal within Gaussian convectional boundary layer (CBL). With regard to assessment of the parameters and pollutants of stack outlet, the amount of particulate matter was measured as the most important pollutant in the region. Then, via dispersion and diffusion modeling of pollution (AERMOD) along with environmental measurements, the nature of dispersion of this pollutant in the analysis of the surrounding areas was verified. According to the presented results, the highest level of concentration for particulate matters in all areas affected by cement factory amounts to 43.68 (μg/m3) which occurred at a distance of 1500 m in the east direction and 2100 m in the north direction.
Show more [+] Less [-]A framework of Trapezoidal Fuzzy Best-Worst Method in Location Selection for Surface Water Treatment Plant Full text
2024
Debnath, Kalyani | Debnath, Piyali | Choudhury, Sudipa | Saha, Apu | Majumdar, Abhijit
Decision-making under uncertainty refers to a dilemma when a decision-maker is aware of a variety of potential natural states but lacks adequate information to assign any probabilities of occurrence to them. The uncertainty related to the input parameters is one of the main issues in the majority of decision-making situations. Uncertainty may produce some irrational results, which could make the decision-making process even more challenging. To overcome this challenge, a fuzzy extension of Best-Worst Method (BWM) has been proposed, using trapezoidal fuzzy sets, to combine the advantages of a reduced number of pair-wise comparisons and easy handling of ambiguity. The criteria and alternatives have been evaluated by the proposed Trapezoidal Fuzzy Best-Worst Method (TrFBWM), where the weight of each element is represented by a Trapezoidal Fuzzy Number (TrFN). To verify the coherence of judgment, the consistency ratio is evaluated for TrFBWM. The proposed method is then applied to the location selection of a water treatment plant along the bank of the Brahmaputra river in Assam. The obtained results are compared to one previous work and found that the outcomes of the proposed method indicate a good agreement with that. The outcomes of the study provide useful insights for selecting a suitable location for a surface water treatment plant which can also be extended to other service facilities.
Show more [+] Less [-]Purification of Heavy Metals Contaminated Groundwater by Electro-Coagulation Process Using Graphite Electrodes Full text
2024
Muhibbu-Din, Eniola Ismail | Jimoh, Heekmah Oiza | Kehinde, David Pelumi | Tinuoye, Ifeoluwa Agnes
The application of the electro-coagulation process to the identified contaminated groundwater at Abala community, a suburb of Ilorin metropolis in Kwara state, Nigeria, is the subject of this study. The groundwater samples were electro-coagulated in a batch reactor of 2.5L containing 1 litre volume of contaminated groundwater for 1 hour per run using a DC power supply ranging from 10v to 20v at constant current 5amp and 2amp to 6amp at constant voltage 10v using graphite electrodes. The results revealed that electro-coagulation process can reduce turbidity, TDS, Electrical Conductivity, BOD, TOC, COD, and color by 97.3 %, 91.2 %, 91.1 %, 96 %, 99.7%, 99.7%, 79.9%, and 82.96 %, respectively. Through Atomic Absorption spectroscopy analytical study, the process also shows removal efficiency of Manganese, Iron, and Zinc of 82.96 percent, 70.0 percent, and 95.30 percent, respectively. The outcome of the electro-coagulation process met the World Health Organization (WHO), the United States Environmental Protection Agency (USEPA), and the Water Environment Partnership In Asia (WEPA) criteria for both drinking water and general industrial wastewater discharge guidelines. The electro-coagulation treatment for contaminated groundwater was efficient and effective, therefore it is recommended in this study for Nigerians.
Show more [+] Less [-]Modeling Airflow in Urban High-Rise Building Areas and Climate Comfort Full text
2024
Zahedifar, Tahmineh | Darabi, Hassan
Urban morphology impacts micro-climates, solar energy absorption, air flow, wind patterns, energy consumption, and air pollution concentration. Temperature control in public spaces reduces heat island formation, while ventilation corridors potentially improve air quality. However, despite the literature on airflow and urban tall buildings providing valuable insights, further research is needed to understand the complex relationship between airflow patterns and urban high-rise buildings. This research should consider factors such as landscape types, building height, density, and orientation. This research aims to examine airflow patterns in high-rise buildings that are influenced by nearby land use, which can impact ventilation and climate comfort. To investigate these objectives, we utilized the Universal Thermal Climate Index (UTCI) and Predicted Mean Vote Index (PMV) by conducting simulations using ENVI-met software. The results revealed that buildings with narrower widths have better wind warded front conditions, while those with an unfavorable wind angle or a narrow facade are less comfortable. Public spaces that face the wind benefit from improved ventilation. It is essential to consider the optimal arrangement, ventilation, and height of buildings to ensure the favorable airflow. Factors such as the placement of trees, the use of porous walls, water features such as fountains and sprinklers, and the local climate all contribute to creating better wind conditions. Investigating the reciprocal interaction between the landscape, high-rise buildings, and climate comfort could be considered in future research.
Show more [+] Less [-]