A review on efficient electromagnetic interference shielding materials by recycling waste—a trio of land to lab to land concept

Environmental Science and Pollution Research - The materials used in electrical and electronic applications have great importance and broader applications, but they have severe electromagnetic...     

Short-term Emissions of Ammonia and Carbon Dioxide from Cattle Urine Contaminated Tropical Grassland Microcosm

The study was designed to understand the emissions of ammonia (NH₃) and carbon dioxide (CO₂) from a single cattle urination event on a tropical grassland and underline the significance of the emissions in the context of huge animal population grazing on large pasture areas in some countries. Emissions of ammonia (NH₃) and carbon dioxide (CO₂) were monitored for three weeks from a tropical grassland (dominated by Cynodon dactylon Pers.) microcosm contaminated with cow and buffalo urine. The grassland microcosms were treated with urine (50 and 100 ml of each) only once and irrigated with water once every week. Ammonia was sampled by an automatic sampling system comprising of a vacuum pump, three-way stopcocks and rubber tubing and an impinger containing suitable absorbing solution (H₂SO₄), connected to the tubing suitably. The sampled gas, after sucked by the vacuum pump and absorbed in H₂SO₄, was allowed to enter the closed microcosm again maintaining internal pressure of the microcosm. Carbon dioxide was sampled by absorption in an alkali (NaOH) trap inside the microcosm. Both NH₃ and CO₂ emissions were highly variable temporally and there was no continuous increasing or decreasing emission trend with time. Respectively, 45 and 46% of total NH₃-N were emitted within first 48 h from 50 and 100 ml cow urine application while the corresponding values for buffalo urine were 34 and 32%. Total NH₃-N emissions, integrated for sampling days (i.e. 1, 2, 3, 4, 6, 15, 18 and 21st) were 11 and 6% in cow and 8 and 5% in buffalo urine, of the total-N added through 50 and 100 ml urine samples. Carbon dioxide emissions were standardized at 25 ^∘C by using a suitable formula which were lower than actual emissions at actual soil temperature (> 25 ^∘C). Carbon dioxide emission rates were classified on the basis of soil repiratory classification and classes ranged from moderately low soil activity up to unusually high soil activity, the latter observed only on very few sampling days. Grasses in the microcosm had shown appreciable growth after urine application. Although variable and somewhat unpredictable, emissions were appreciable and that too only from a patch of single urination, indicating to the huge magnitude of total emissions under the scenario of thousands of cattle grazing on hundreds of acres of grasslands in a tropical country.     

Response Surface Method Coupled with First-Order Reliability Method Based Methodology for Groundwater Flow and Contaminant Transport Model for the Uranium Tailings Pond Site

Groundwater flow and contaminant transport modelling is carried out to predict the concentrations of radionuclides in groundwater beneath the tailings pond. This is used as a tool for radiological impact assessment studies. The geo-hydrological parameters involved in the modelling exhibit inherent uncertainty associated with their values. This uncertainty may get propagated to the model output, i.e. the dose to the public. The propagation of the uncertainty in the input parameters to the output is modelled using suitable methods of probabilistic analysis. Response surface method coupled with first-order reliability method is used to develop a methodology for estimating the probability that the dose rate value through drinking water pathway at a location around the tailings pond exceeds the WHO guidelines for drinking water, termed as the probability of exceedance of acceptable levels. This method also gives the estimate of sensitivity of the probability of exceedance to the different input parameters. It is observed that the probability of failure decreases as the distance from tailings pond centre is increased and beyond a distance of around 0.5 km from tailings pond centre, the probability reduces to zero. The work also brings out the importance of quantifying the uncertainty in case of actual field problems where there is wide variation in the values of the various parameters within the domain under study.     

Nanomaterials for biofuel production using lignocellulosic waste

Production of biofuels using second-generation, non-food, lignocellulosic waste biomass is a sustainable approach that solve the economic issues of fossil fuels and environmental pollution. The major issues of biofuel production are biomass complexity, pretreatment, enzyme denaturation and cost. This article reviews the application of nanomaterials for biofuel production from various lignocellulosic wastes.     

Bio-efficacy evaluation of nanoformulations of β-cyfluthrin against Callosobruchus maculatus (Coleoptera: Bruchidae)

In the present investigation, bioefficacy of developed β-cyfluthrin formulations, utilizing laboratory synthesized poly(ethylene glycols) based amphiphilic copolymers, were evaluated against Callosobruchus maculatus (Coleoptera: Bruchidae). The bioefficacy data indicated that the formulations developed by utilizing polymers having PEG - 1500 (3c) and PEG - 2000 (3d) as the hydrophilic segment showed greater efficacy after 14 days as evident from EC(50) values (2.2 and 1.58 mg L(-1) respectively). Also, release from the commercial SC formulation was faster than developed formulations as the commercial formulation had the lowest EC(50) value on the first day (0.51 mg L(-1)). The mean EC(50) of the commercial formulation against C. maculatus was quite high as compared to those of developed formulations. The results suggest that depending upon the polymer matrix used, the application rate of β-cyfluthrin can be optimized to achieve insect control at the desired level and period. The results described in this paper are promising and provide a comparison of developed formulations with the commercial one showing an earlier degradation of β-cyfluthrin in the latter and relatively prolonged activity in the former.     

Application of Unknown Groundwater Pollution Source Release History Estimation Methodology to Distributed Sources Incorporating Surface-Groundwater Interactions

Sources of contamination of groundwater are often difficult to characterize. However, it is essential for effective remediation of polluted groundwater resources. This study demonstrates an application of the linked simulation-optimization based methodology to estimate the release history from spatially distributed sources of pollution at an illustrative abandoned mine-site. In linked simulation-optimization approaches a numerical groundwater flow and transport simulation model is linked to the optimization model. In this study, topographic and geologic characteristics of the abandoned mine-site were simulated using a three-dimensional (3D) numerical groundwater flow model. Transport of contaminant in the groundwater was simulated using a 3D transient advective-dispersive contaminant transport model. Adsorption or chemical reaction of the contaminant was not considered in the contaminant transport model. Adaptive simulated annealing (ASA) was employed for solving the optimization problem. An optimization algorithm generates the candidate solutions corresponding to various unknown groundwater source characteristics. The candidate solutions are used as input in the numerical groundwater transport simulation model to generate the concentration of pollutant in the study area. This information is used to calculate the objective function value, which is utilized by the optimization algorithm to improve the candidate solution. This process continues until an optimal solution is obtained. Optimal solutions obtained in this study show that the linked simulation-optimization based methodology is potentially applicable for the characterization of spatially distributed pollutant sources, typically present at abandoned mine-sites.     

Biocatalytic amidation of carboxylic acids and their antinemic activity

A series of novel N-alkyl substituted amides, synthesized by enzyme catalysis, were evaluated against root-knot nematode, Meloidogyne incognita and found to have potential antinemic activity. The corresponding amides were prepared by the condensation of equimolar amounts of carboxylic acids with different alkyl amines in the presence of Candida antarctica lipase at 60–90°C in 16–20 h. The reactions were carried out in a non - solvent system without the use of any activating agents. All the products were obtained in appreciable amounts and the yields for different compounds varied between 77.4–82.3%. The synthesized compounds were characterized using spectroscopy techniques namely Infra Red (IR) and Nuclear Magnetic Resonance (NMR) (¹H and ¹³C). Nematicidal activity of synthesized amides was evaluated against J₂s of Meloidogyne incognita at 500, 250, 125 and 62.5 ppm concentrations after 24 h, 48 h and 72 h of exposure. Among all the tested compounds, N-propyl-butyramide, N-propyl-pentanamide and N-propyl-hexanamide were found to possess significant activity with LC₅₀ values of 67.46, 83.49 and 96.53 respectively. N-propyl-butyramide with LC₅₀ value of 67.46 ppm was found to be most active amide against J₂s of Meloidogyne incognita. The bioactivity study showed that an increase in alkyl chain significantly decreased the activity of amides against root-knot nematode.     

Mercury in coal from south eastern coalfield and mercury partitioning at sub-critical coal-fired power plant

Journal of Material Cycles and Waste Management - India is considered as one of the major mercury emitters of the world. Coal combustion in power plants is the foremost source of mercury emissions....