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991.
A. Vignesh Arun. S. Siddarth B. Ramesh Babu 《Journal of Material Cycles and Waste Management》2017,19(1):155-162
This contribution reports a novel and cost efficient strategy for nickel ion removal from metal finishing effluents by electro-dissolution of scrap aluminium and iron sacrificial anodes. Electro-coagulation of effluent was carried out at 30 mA/cm2 current density for 60 min. The nickel ion concentration of electroplating effluent was analysed by Atomic Absorption Spectroscopy. SEM images of iron and aluminium scrap anodes were critically analysed. Parameters such as heavy metal removal, anode dissolution rate with respect to heavy metal removal, reaction kinetics and cost estimation have been elaborately studied. Electro-coagulation at 30 mA/cm2 for 60 min using iron and aluminium scrap anodes resulted in 95.9 and 94.1 % nickel ion reduction, respectively, with 0.0094 and 0.0053 g/ppm dissolution rates. The energy consumption for scrap aluminium and iron anodes was 0.0547 kWh/L. Loose internal bonding and spongy surface morphology of used metal scrap render high porosity and active surface area, enhancing reaction rate. Low cost and ready availability of waste scrap makes the process of electro-coagulation economically viable. Thus, the findings from this contribution point decisively at the superiority of waste metal scrap-based anodes for economic and environmentally sustainable heavy metal ion removal from metal finishing effluent. 相似文献
992.
Nur Zahidah Rozaki Seng-Neon Gan Desmond Teck-Chye Ang 《Journal of Polymers and the Environment》2017,25(2):286-295
Oil-modified polyesters were synthesized to serve as polymeric plasticizers for PVC. A total of four polymeric plasticizers with different average molecular weights were prepared. Characterizations were done using Fourier-transformed infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and gel permeation chromatography. Some of the tests conducted on PVC films include thermal stability test using thermogravimetric analyser, determination of glass transition temperature (Tg), plasticizer migration and leaching resistance test, morphology study of plasticized PVC films using field emission scanning microscope, toxicity test, and tensile test. Owing to the plasticizing effect of the palm oil-based compound, Tg of the plasticized PVC has decreased to an average of 65 °C at 20 wt% loading. The polymeric plasticizer is also able to contribute positively to the thermal stability and mechanical properties of the PVC films. Some of the advantages of incorporating polymeric plasticizer with high molecular weight includes lower rate of leaching from plastic, and improved tensile strength and elongation at break. Besides, thermal stability of the plastic studied using Kissinger’s and Flynn–Wall–Ozawa’s approaches shows that PVC blended with high molecular weight oil-modified polyester is more thermally stable, evidenced by the increase in the activation energy of decomposition, Ed. Toxicity test using brine shrimp egg shows encouraging results, where the oil-based plasticizer is considerably less toxic compared to some of the commercial plasticizers. 相似文献
993.
By means of environmental education, teachers are supposed to intervene in pupils’ awareness and concern of environmental
issues. Teachers’ environmental attitudes, however, have rarely been studied. We analysed 367 German pre- and in-service teachers’
environmental attitudes for their structure and socio-economic correlates within the frame of a European project. Thus, we
retrieved for adults the two-dimensional model of ecological values (2-MEV) presented for adolescents by Bogner and Wiseman
(Sci Educ Int 15(1):27–48, 2004). For the two domains, Preservation and Utilisation, the psychometric structure was confirmed and discriminative correlations
with age, gender and teaching subject were unveiled. Further research is needed to deduce the implications for teaching practice. 相似文献
994.
995.
Ecological disturbances of forests by insects have a complex array of associated human dimensions presenting complications
for natural resource decision making and relationships between stakeholders and managers. This article discusses the human
context of forest disturbances by insects by reviewing four cases of bark beetle forest disturbance from British Columbia
in Canada, Bavarian Forest National Park in Germany, the Kenai Peninsula in Alaska, and the north central region of Colorado.
Findings and lessons learned from these studies are outlined along with their implications for managing forest disturbances
by insects in general. Conclusions focus on the need to assess the broad array of impacts and risks perceived by local residents
and the capacity for local action and involvement in managing forest disturbances. Communication and interaction between resource
managers and local stakeholders can facilitate the identification of management priorities and potentially reduce some of
the risks associated with forest disturbances by insects. 相似文献
996.
A framework for dissolved oxygen (DO) modeling of the Ravi River has been developed based on a combination of laboratory measurements
and field and monitoring data. Both the classical Streeter-Phelps (CSP) and the modified Streeter-Phelps (MSP) models are
used for DO simulations. The MSP model considers the carbonaceous biochemical oxygen demand (CBOD) and nitrogenous biochemical
oxygen demand (NBOD) separately, whereas the CSP model is evaluated considering only the CBOD and NBOD is incorporated in
the overall BOD utilization rate. CBOD, NBOD and BOD rates have been determined through long-term BOD analysis of five main
wastewater outfalls and two surface drains discharging into the Ravi River over a 98 km stretch. Analysis by Thomas Method
manifests strong coefficient of determination “R2” between 0.72 and 0.98 for all the three types of BOD rates. Sensitivity analyses have also been carried out to find out
a suitable reaeration rate formula for highly variable flows in the Ravi River. The CSP model results based on classical approach
of considering only CBOD show significant difference between the model predictions and field measurements suggesting that
NBOD needs to be incorporated for the model development. The dissolved oxygen values calculated using the MSP model and the
CSP model based on overall BOD rate are in close agreement with field measurements and are thus suitable to model DO levels
in the Ravi River. 相似文献
997.
Marian Leimbach Nico Bauer Lavinia Baumstark Ottmar Edenhofer 《Environmental Modeling and Assessment》2010,15(3):155-173
Within this paper, we present the novel hybrid model REMIND-R and its application in a climate policy context based on the
EU target to avoid a warming of the Earth’s atmosphere by more than 2°C compared to the pre-industrial level. This paper aims
to identify necessary long-term changes in the energy system and the magnitude of costs to attain such a climate protection
target under different designs of the post-2012 climate policy regime. The regional specification of mitigation costs is analyzed
in the context of globalization where regions are linked by global markets for emission permits, goods, and several resources.
From simulation experiments with REMIND-R, it turns out that quite different strategies of restructuring the energy system
are pursued by the regions. Furthermore, it is demonstrated that the variance of mitigation costs is higher across regions
than across policy regimes. First-order impacts, in particular, reduced rents from trade in fossil resources, prevail regardless
of the design of the policy regime. 相似文献
998.
R. Y. M. Kangalawe 《Environment, Development and Sustainability》2010,12(4):449-461
This article examines the changes in land-use/cover types in the Irangi Hills, central Tanzania during the last 45 years and
how such changes have influenced environmental and agricultural sustainability in the area. The spatial and temporal changes
of land-use/cover were analysed through aerial photographs interpretation. Local perceptions and experiences of changes were
addressed through household interviews and field observations. Results from this study show that during the last 45 years
open and wooded grasslands, and other tree-cover types covered about 40% of the land area, ranging from 29% in 1960 to 43–45%
between 1977 and 1992. Also, during the same period both the total area and spatial distribution of cultivated fields varied
greatly. The cultivated area increased from 31% in 1977 to 35% in 1992, mainly due to agricultural expansion into areas formerly
used for grazing and in sandy watercourses that shrunk by 55% between 1977 and 1992. The spatial distribution of the different
land-use/cover types is influenced by variations in the scale of soil erosion and soil-conservation initiatives implemented
in the Irangi Hills since the early 1970s. However, with increasing pressure on the land, and the declining capacity of the
soil conservation authority, sustaining agricultural production in the area remains a major challenge. 相似文献
999.
E. Yu. Zakharova 《Russian Journal of Ecology》2012,43(2):162-168
Phenotypic variation in the widespread Siberian and Mongolian butterfly species Coenonympha amaryllis (Stoll, 1782), an indicator of undisturbed steppe communities, is analyzed. It is shown that its size variation is influenced
by a complex of climatic factors, the most important of them being the average starting date of the frost-free period and
average annual temperature in the region. Longitude-dependent variation in size is described by a “sawtooth curve” characteristic
of species with changing voltinism. 相似文献
1000.