Studies on influence of natural biowastes on cellulase production by Aspergillus niger

The objective of this study was to determine the influence of natural biowaste substrates such as banana peel powder and coir powder at varying environmental parameters of pH (4-9) and temperature (20-50 degrees C) on the cellulase enzyme production by Aspergillus niger. The cellulase enzyme production was analyzed by measuring the amount of glucose liberated in IU ml(-1) by using the dinitrosalicylic acid assay method. The substrates were pretreated with 1% NaOH (alkaline treatment) and autoclaved. The maximum activity of the enzyme was assayed at varying pH with temperatures being constant and varying temperatures with pH being constant. The highest activity of the enzyme at varying pH was recorded at pH 6 for banana peel powder (0.068 +/- 0.002 IU ml) and coir powder (0.049 +/- 0.002 IU ml(-1)) and the maximum activity of the enzyme at varying temperature was recorded at 35 degrees C for both banana peel powder (0.072 +/- 0.001 IU ml(-1)) and coir powder (0.046 +/- 0.003 IU ml(-1)). At varying temperatures and pH the high level of enzyme production was obtained at 35 degrees C and pH 6 by using both the substrates, respectively. However among the two substrates used for the production of cellulases by Aspergillus niger banana peel powder showed maximum enzymatic activity than coir powder as substrate.     

Investigation on microstructural and mechanical properties of microwave processed dissimilar joints

In the present work, microwave joining of stainless steel (SS-316) to mild steel (MS) in bulk form has been successfully carried out using a multimode applicator at 2.45 GHz and 900 W. Principles of hybrid heating were employed using a susceptor medium so as to initiate coupling of microwave with the metals. A nickel based metallic powder was used as a sandwich layer between the bulk pieces. Samples were exposed to microwave radiation in atmospheric conditions. Resulting joints were characterized using field emission scanning electron microscope (FESEM), X-ray diffractometer, microhardness tester and universal testing machine. Microstructure study showed the faying surfaces were well fused and got bonded on either side of the base material. Formation of cementite and metallic carbides were evidenced. The average observed Vickers’ microhardness of core of the joint area was observed to be 133 H_v with 0.58% porosity. The ultimate tensile strength of the joint was found to be 346.6 MPa with percentage elongation of 13.58%. Fractography reveals that the joints failed due to both shearing of the brittle carbides and oxides as well as due to plastic flow of the ductile matrix under tensile loading.     

Twenty five years of industrial development: a study of resource use rates and macro-efficiency indicators for five Asian countries

Economic and population growth in Asia over the last three decades has been unprecedented. While conventional economic indicators have been increasing consistently, indicators of resource and environmental quality have been deteriorating, raising questions about the implications of future growth. Economic growth in the future is considered to be contingent on ensuring a more efficient use of natural resources, while simultaneously striving to reduce environmental impacts. We examine time trends of three efficiency indicators; agricultural efficiency, energy efficiency of economic production and carbon efficiency of energy use, for the five most populous countries in Asia in order to assess whether industrial development has lead to increased resource use efficiency and an associated reduction in total resource use and environmental impacts. Our results indicate that agricultural efficiency has decreased in all five countries. Results are mixed for energy and carbon efficiencies. Where increases in energy and carbon efficiency have occurred, they have been completely overwhelmed by absolute increases in energy use and carbon emissions caused by increases in the scale of economic activity. Based on this analysis, we study the potential for further improvements and policy implications for future food supply, energy consumption and carbon emissions in the region.     

Plasma lipid profiles and risk of cardiovascular disease on occupational exposure in Karimnagar

Occupational exposure is unregulated in developing countries like India, and becoming the most common cause of disease of environmental origin. The present study was aimed to investigate the effects of occupational exposure on plasma lipid profiles, and risk of cardiovascular diseases. A total of 79 human volunteers were included in the study. Control subjects were healthy housewives of Karimnagar, India. Occupationally exposed individuals included different occupational workers like petrol station attendants, battery chargers, drivers, welders, pesticide-exposed workers, painters, and auto mechanics. These subjects were shown to be chronic occupationally-exposed for at least three years, and neither associated with any other chronic pathological conditions like hypertension or diabetes, nor under any medication other than analgesics during the month preceding the study. Subjects with excessive high or low caloric intake were excluded from the study. Total cholesterol (TC), LDL cholesterol, triglycerides (TG), VLDL cholesterol, LDL/HDL cholesterol, and TC/HDL ratio in these subjects were significantly higher than those in control subjects, whereas HDL cholesterol was not markedly affected. Blood pressure (systolic and diastolic), and other anthropometric parameters (body mass index (BMI), body fat index (BFI), body surface area (BSA)) were not significantly different between groups. Data suggest that chronic occupational exposure increases plasma lipid levels and is thereby associated with cardiovascular complications.     

Genotoxicity of vegetables irrigated by industrial wastewater

IntroductionPollution of natural waters with waste effluentsarising from various industries has become a seriousproblem in India.In Rajasthan particularly,textilemills represent an important economic sector.Effluents from these textile and other dye-relat…     

The Development of a Model to Examine Source-Receptor Relationships for Visibility on the Colorado Plateau

This paper describes the development and application of the Visibility and Haze in the Western Atmosphere (VISHWA) model to understand the source-receptor relationships that govern chemical species relevant to visibility degradation in the western United States. The model was developed as part of a project referred to as Visibility Assessment for Regional Emission Distributions (VARED), the objective of which is to estimate the contributions of various geographical regions, compounds, and emission

sources to light scattering and absorption by particles on the Colorado Plateau.

The VISHWA model is a modified version of a comprehensive Eulerian model, known as the Acid Deposition and Oxidant Model.1 The modifications were designed to obtain the computational efficiency required to simulate a one-year period at about 1/25th of real time, and at the same time incorporate mechanistic features relevant to realistic modeling of the fate and transport of visibility degrading species. The modifications included use of a condensed chemical mechanism; incorporation of reactions to simulate the formation of secondary organic particles; and use of a semi-Lagrangian advection scheme to preserve concentration peaks during advection.

The model was evaluated with 1992 air quality data from Project MOHAVE (Measurements of Haze and Visual Effects) intensive experiments. An important conclusion of this evaluation is that aqueous-phase oxidation of SO2 to sulfate in nonprecipitating clouds makes a significant contribution to observed sulfate levels during winter as well as summer. Model estimates of ambient sulfate

for the winter intensive were within a factor of 2 of the observations for 75% of the values. The corresponding statistic for the summer intensive was 90%. Model estimates of carbon were within a factor of 2 of the limited set of observations.     

Catalytic Gasification of Coal Using Eutectic Salts: Recovery,Regeneration, and Recycle of Spent Eutectic Catalysts

Abstract

Catalyst recovery studies were conducted for gasified chars produced from steam gasification of Illinois #6 coal catalyzed with two different catalyst systems. A ternary (43.5 mol% Li₂ CO₃ –31.5 mol% Na₂ CO₃ –25 mol% K₂ CO₃ ) and a binary (29 mol% Na₂ CO₃ –71 mol% K₂ CO₃ ) eutectic catalyst system were used for gasifying coal. Various extraction schemes, such as water extraction, H₂ SO₄ extraction, and acetic acid extraction, were evaluated with respect to their extraction efficiencies. Effects of major process variables, such as solvent-to-char ratio, mixing time, temperature, and concentration, on the extraction efficiency were evaluated. A process schematic for the entire catalyst recovery, regeneration, and recycle scheme was developed and the preliminary process economics were determined based on these extraction schemes. H₂ SO₄ extraction was found to be the most desirable. It also turned out to be more attractive than a once-through throwaway system.     

Heavy metal content in soil reclaimed from a municipal solid waste landfill

Residues reclaimed from a municipal solid waste (MSW) landfill were characterized for the concentrations of a number of heavy metals. The residue fractions analyzed included a fine fraction (<0.425 mm), an intermediate fraction (>0.425 and <6.3 mm) and a fraction consisting of paper products that could ultimately degrade to a smaller size. The intermediate fraction appeared to be organic in nature, while the fine fraction was more soil-like. In general, the metal concentrations were greatest in the intermediate fraction and lowest in the fine fraction. The effect of sample age on the elemental content was also investigated. The concentrations of several elements were greater in older samples (sample approximately 8 years in age) when compared to newer samples (sample approximately 3 years in age). Limitations associated with the land application of residual soil (composed of the fine and intermediate fractions) were assessed by comparing measured concentrations to regulatory threshold values. In general, most metal concentrations were below regulatory thresholds for use in unrestricted settings. At the concentrations measured, however, several elements might limit reuse options, depending on which regulatory threshold serves as a benchmark. Elevated concentrations of arsenic presented the greatest limitation with respect to common US thresholds while elevated cadmium concentrations presented the greatest limitation when compared to UK thresholds. The source of the arsenic was determined to be the waste, not the cover soil.     

Steady-state design of horizontal systems for liquids addition at bioreactor landfills

The key parameters for designing a horizontal source (horizontal trenches, infiltration ponds, infiltration galleries or blankets) for steady state are the rate liquids can be added to the source, the lateral and vertical extents of the zone of impact of the source, and the liquids volume needed to wet the waste within the zone of impact at steady state. This paper presents charts that a designer can use to estimate these key parameters as functions of source dimensions, injection pressure, and municipal solid waste properties (porosity, hydraulic conductivity, and anisotropy) for designing a new or analyzing an existing horizontal source system for liquids addition to landfilled waste. SEEP/W was used to model liquids flow from a horizontal source in a range of conditions practically encountered for such systems. The governing equation (Richard’s equation) and the boundary conditions were analyzed to formulate dimensionless variables by normalizing the design parameters (flow rate, injection pressure, the lateral zone of impact, injection pressure, and the added liquids volume) with the waste properties and source dimensions. The simulation results were transformed to the respective dimensionless forms and presented in design charts to estimate the key design parameters as functions of the source dimensions, waste properties, and injection pressure. The presentation of the modeling results in the dimensionless form facilitates their use beyond the conditions modeled. A solved example is presented to demonstrate the use of the design charts. The approach presented in the paper should be considered as approximate and designers should use their judgement and experience when using these charts for designing a horizontal liquids addition system for a specific site.