Affiner votre recherche
Résultats 1-10 de 3,224
Comparative analysis of jatropha and karanja-based biodiesel properties, performance and exhaust emission characteristics in an unmodified diesel engine
2015
Singh, Yashvir | Singla, Amneesh
An ever-increasing drift of energy consumption, unequal geographical distribution of natural wealth and the quest for low carbon fuel for a cleaner environment are sparking the production and use of biodiesels in many countries around the globe. In this work, jatropha and karanja biodiesels were produced from the respective crude vegetable oils through transesterification, and the different physical properties of the produced biodiesels have been presented and found to be acceptable according to the ASTM biodiesel specification standard. This paper presents the experimental results of the research carried out to evaluate the BTH, BSFC exhaust emission characteristics of jatropha and karanja blends in a single-cylinder diesel engine at different engine load. Comparative measures of brake thermal efficiency, smoke opacity, HC, CO, and NOx have been presented and discussed. Engine performance, in terms of higher brake thermal efficiency and lower emissions (HC, CO, NOx) with jatropha-based biodiesel (JB50) operation, were observed compared to karanja-based biodiesel (KB50).
Afficher plus [+] Moins [-]Consumer attitudes and perceptions on electronic waste: An assessment
2015
Saritha, Vara | Sunil Kumar, KA | Srikanth Vuppala, NV
The electronics industry is one of fastest growing manufacturing industries in India. However, the increase in the sales of electronic goods and their rapid obsolescence has resulted in the large-scale generation of electronic waste, popularly known as e-waste. E-waste has become a matter of concern due to the presence of toxic and hazardous substances present in electronic goods which, if not properly managed, can have adverse effects on the environment and human health. In India, the e-waste market remains largely unorganized, with companies being neither registered nor authorized and typically operating on an informal basis. In many instances, e-waste is treated as municipal waste, because India does not have dedicated legislation for the management of e-waste. It is therefore necessary to review the public health risks and strategies in a bid to addressthis growing hazard. There is the strong need for adopting sustainability practices in order to tackle the growing threat of e-waste. In the present work, we attempt to identify the various sources and reasons for e-waste generation, in addition to understanding the perception of the public towards e-waste management. This study aims to induce an awareness of sustainability practices and sustainability issues in the management of E-waste, especially waste related to personal computers (PCs) and mobile phones. From the results of the study, we concluded that the majority (90%) of the public is ignorant about e-waste and its issues; hence, there is a strong requirement for spreading awareness about the growing hazard of E-waste.
Afficher plus [+] Moins [-]Groundwater quality determination regarding major anions and cations (Case study of an aquifer in the Lut Desert, Iran)
2015
Nasrabadi, Touraj | Baghvand, Akbar | Vosoogh, Ali
Groundwater quality regarding major anions and cations in the Birjand Plain located in the largest desert in Eastern Iran was monitored in this study. Fifteen boreholes were considered as sampling stations and the parameters pH, TDS, EC and major anions and cations were measured in groundwater samples. The dominant groundwater types can be introduced as sodium-chloride and magnesium-sulphate. The majority of samples were within the not-suitable category for drinking uses. Regarding agricultural use, around 80 and 50 per cent of samples indicated a very high salinity hazard and a very high sodium alkali hazard, respectively. Spatial distribution of salinity was also monitored within the study area. If the study area was considered to be a semicircle, the centre appeared to be the least polluted area, while towards the peripheral surroundings, an increasing behaviour was observed. Intrusion of salt water from eastern and western parts of the study area caused severe groundwater degradation. The relatively better quality of groundwater in southern areas may be attributed to a chain of mountains located along south of the study area. The prevention of uncontrolled groundwater withdrawal must be regarded to cease the salinization trend and to prepare the required infrastructure for implementing the artificial recharge projects.
Afficher plus [+] Moins [-]Spectrophotometer-based student education program on health hazard assessment due to Cr(VI) and Pb contamination in surface and groundwaters of Hyderabad City, India
2015
Das Sharma, Mala | Juyal, Archana | Karuna, Mantha | Das Sharma, Subrata
A student-centric research education program with the active participation of undergraduate students is initiated. The aim is to imbibe ―responsible citizenship behavior‖ in them so that each member becomes conscious and well trained to take up environmental-related issues and challenges for long-term sustainability of the ecosystem. In this work, we report spectrophotometer-based estimation of hexavalent chromium (57-268 gL-1) and lead (34–158 gL-1) concentrations in different surface waters and groundwater samples in and around the city of Hyderabad, India. Our results indicate that the studied surface water bodies and aquifers are contaminated to variable degrees and pose a serious threat to the ecosystem. In view of low geochemical baseline values for chromium and lead, the origin of heavy metal pollution is inferred to be anthropogenic, mainly originating from industrial effluents. The toxicological data are integrated with health data for risk assessment and impending health hazard. Finally, the novelty of this student-centric research program is highlighted.
Afficher plus [+] Moins [-]Remote sensing technology for mapping and monitoring vegetation cover (Case study: Semirom-Isfahan, Iran)
2015
Jabbari, Somayyeh | Khajedin, Seyed Jamaledin | Jafari, Reza | Soltani, Saeed
To determine the suitable indices for vegetation cover and production assessment based on the remote sensing data, simultaneous digital data with field data belonging to the spring rangeland of the Semirom-Isfahan province were analyzed. During two years of monitoring the annual, grass, forb, and shrub vegetation cover and the total production data from 86 were collected. The Global Positioning System (GPS) was used to measure the coordinates of plots and transects. Geometric correction and histogram equalization were applied in image processing, and image digital numbers were converted to reflectance numbers. In the next stage, all vegetation indices were calculated from the Advanced Wide Field Sensor (AWiFS) image data and compared with the vegetation cover estimates, at monitoring points, made during field assessments. A linear regression model was used to select suitable vegetation indices. The results showed that there were significant relationships between the satellite data and the vegetative characteristics. Among the indices, the Normalized Difference Vegetation Index (NDVI) consistently showed significant relationships with the vegetation cover. The estimation of the vegetation cover with the NDVI vegetation index was more accurately predicted within rangeland systems. Using the produced model from the NDVI index vegetation crown cover, percentage maps were produced in three class percentages for each image. Generally introduced indices provided accurate quantitative estimation of the parameters. Therefore, it was possible to estimate cover and production as important factors for range monitoring using the AWiFS data. The Remote sensing data and the Geographic Information System are the most effective tools in natural resource management.
Afficher plus [+] Moins [-]Laser land levelling as a strategy for environmental management: the case of Iran
2015
Tohidyan Far, Somayeh | Rezaei-Moghaddam, Kurosh
The impact assessment method seeks to bring about a more ecologically, socio-culturally and economically sustainable and equitable environment. Determining the main factors affecting the attitudes of stakeholders is crucial for understanding the impacts of development plans. This approach helps planners and decision makers to identify the values and traits of stakeholders and accelerate the diffusion of innovations through designing proper incentives and removing available obstacles. The purpose of this study is to examine factors affecting laser land levelling project impacts in Fars Province, Iran. The sample included 285 farmers who were selected using multi-stage random sampling. The validity and reliability of the questionnaire were measured and revisions were made to improve measurement scales. The results of structural equation modelling indicated that reduction in water consumption was the most important variable which affected the recognition of impacts among laser land levelling adopters. Furthermore, laser land levelling impacts as dependent variables were influenced by the direct effect of the duration of adoption, attitude towards water and soil conservation, need perception and attitude toward prior projects. Based on the results, practical recommendations have been presented.
Afficher plus [+] Moins [-]Spatial–Temporal Monitoring of Ecotonal Belt Using Landscape Ecological Indices in the Central Elburz Region: Remote Sensing and GIS Analysis
2015
Yavari, Ahmad Reza | Jafari, Hamid Reza | Hashemi, Seyyed Mahmood
Iran has mountainous landscapes and half of its surface is occupied by highlands. Moreover, Iran is an arid country and deserts are located at lower altitudes. Most metropolitan areas are positioned in mid-altitudes between mountain and desert. Cities grow upwardly toward the highlands under pressures of urbanization and desertification. Foothill ecotones are a zone between upland mountains and midland plains. Upwardly sprawl of urban centers has transformed the structures and functions of these ecologically strategic belts. In this article, we analyzed the transformational trend of the ecotonal zone in the southern slopes of the central Elburz (Tehran-Karaj urban region). Landsat 7 ETM+ (2000) and 8 OLI (2013) are used to monitor spatial and temporal variability of landscape metrics. The land covers are grouped into four classes: vegetation cover, open space, built area, and water body. Seven landscape metrics are used including: NP, CAP, MPS, AW-MPS, MNND, PARA, and TE. Our results indicate that NP, AW-MPS, TE, and PARA increased whereas CAP and MPS decreased. These results are a sign of the fragmentation process across the ecotonal strip.
Afficher plus [+] Moins [-]Speciation of four heavy metals in agricultural soils around DraaLasfarmine area in Marrakech (Morocco)
2015
Yassir, Barkouch | Alain, Pineau
This study was carried out to 1. determine spatial variations of heavy metal deposition in agricultural soils of two rural communities (OuledBouAicha and Tazakourte) of about 5790 ha in a mining area near Marrakech city in Morocco; 2. to assess the extent of metallic pollution generated by the mining activity and; 3. to identify the key mechanism responsible for this contamination and its relation to mining activity. Soil pollution assessment was carried out on one hand by measurement of the total metal concentration and on the other hand by studying four heavy metals speciation of the studied soils. The chemical forms of four heavy metals in soils around DraaLasfar mine were studied by determining soil Cd, Cu, Pb and Zn species using standard solvent extraction and Atomic Absorption Spectrophotometric techniques. The chemical pools of the metals indicated that the metals were distributed into six fractions with most of them residing in the non-residual fractions thus suggesting how readily the metals are released into the environment. Considering that the metals occur in the most available forms, we suggested that it is most likely that the metals must have been derived from anthropogenic sources especially from the mining activity in the studied region.
Afficher plus [+] Moins [-]Assessing environmental contamination of River Ganga using correlation and multivariate analysis
2015
Bhutiani, Rakesh | Khanna, D.R. | Tyagi, Bharti | Tyagi, Prashant | Kulkarni, Dipali
The aim of this study was to assess the environmental impact of socio-cultural practices on the water quality of River Ganga at the foothills of the Garhwal Himalayas in Uttarakhand State, India. The physico-chemical parameters that contributed to the temporal variation and pollution in the river were identified in this study. Principal component analysis (PCA) and Cluster analysis (CA) were used in the identification of anthropogenic factors (industrial, urban sewage, agricultural, land use and mining activities) and natural factors (soil erosion, weathering). The results of this study show that total coliform, fecal coliform, nitrate, sodium, phosphate, sulphate, TDS (Total dissolved solids), temperature, BOD (Biochemical oxygen demand), calcium and chloride are parameters significantly contributing to pollution load.
Afficher plus [+] Moins [-]Isolation and molecular characterization of bacteria to heavy metals isolated from soil samples in Bokaro Coal Mines, India
2015
Gandhi, Vikram | Priya, Anshu | Priya, Suman | Daiya, Vivek | Kesari, Jitendra | Prakash, Krishna | Kumar Jha, Amrit | Kumar, Kundan | Kumar, Nitish
In recent years, environmental pollution by coal mining is a long-established human activity affecting all levels of life with various environmental impacts by generating heavy metals. The presence of heavy metals even in trace amount is toxic and detrimental to all living organisms. The coal mine area in Bokaro is one of the “Toxic Hotspot” in India. Bacteria have evolved uptake and efflux mechanisms to adapt in heavy metals contaminated environments and thus represent a potential source for bioremediation processes. In the present study, we isolated and characterized eight heavy metal resistant bacteria (NK-1 to 8) from soil sample in Bokaro coal mines, India. Isolates were selected based on high level of heavy metal resistance and its biochemical characterization. The following bacteria were identified based on 16S rRNA gene sequencing Enterobacter ludwigii (KM029957; NK-1), Klebsiella pneumonia (KM029958; NK-2), Enterobacter ludwigii (KM029959; NK-3), Enterobacter ludwigii (KM029960; NK-4), Klebsiella oxytoca (KM029961; NK-5), Enterobacter cloacae (KM029962; NK-6), Acinetobacter gyllenbergii (KM029963; NK-7), Enterobacter cloacae (KM029964; NK-8). A high degree of metal resistance associated with multiple antibiotic resistances was also detected in the selected isolate which was confirmed by the presence of plasmid. These isolates can further be used for bioremediation of heavy metals from contaminated site.
Afficher plus [+] Moins [-]