A survey of corrosivity of underground mine waters from indian coal mines

The coal mining industry is facing serious corrosion problems. Millions of litres of water is disposed off from some underground coal mines every day. In this survey, mine water samples from various underground coal mines were collected and analysed in an attempt to correlate the various physicochemical characteristics with their corrosivity. The analyses include determination of the values of pH, alkalinity, acidity, specific conductivity, hardness, total solids, sulphate, chloride, cupric, ferrous and ferric ions. Corrosion rates of steel in minewaters were also measured by weight-loss trial method. The present survey shows that mine waters are nearly neutral, alkaline, midly acidic and highly acidic in nature. The corrosivity of these vary from mildly to extremely corrosive. An evaluation of minewaters corrosivity using Langelier Saturation Index has also been made but no definite relationship has been found between the corrosion rate and Langelier Saturation Index. A classification of the basis of corrosivity of these mine waters is also made. Causes of aggressiveness of Fe³⁺, Cu²⁺, SO₄ ^2?, Cl^? in acid mine waters have also been discussed which conclude that corrosion rates were significantly increased by Fe³⁺ and Cu²⁺ due to their reduction to Fe²⁺ and metallic Cu, respectively. Occurrence of these ions in acid mine waters has also been discussed.     

Near-infrared spectroscopic analysis of macronutrients and energy in homogenized meals

Near-infrared (NIR) reflectance spectroscopy was evaluated as a rapid and environmentally benign technique for the simultaneous determination of macronutrients and energy in commercially available, packaged meals. Reflectance spectra (400–2498 nm) of homogenized meals were obtained with a dispersive NIR spectrometer. Protein and moisture were measured by AOAC reference methods, total fat by a semi-automated acid hydrolysis, solvent extraction, gravimetric method and total carbohydrate calculated. Energy was calculated using Atwater factors. Using multivariate analysis software, PLS models (n = 113–115 products) were developed to relate NIR spectra of homogenized meals to the corresponding reference values. The models predicted components and energy in validation samples (n = 37–38 products), overall, with r² of above 0.96. Ratios of deviation to performance were between 3.6 and 6.6, and indicated adequacy of the models for screening, quality control, or process control. Performance of the models varied substantially when used to predict sub-groups of meals within the validation set.     

Design of a low-power, high performance, 8×8 bit multiplier using a Shannon-based adder cell

In this paper, we have developed a new full-adder cell using multiplexing control input techniques (MCIT) for the sum operation and the Shannon-based technique to implement the carry. The proposed adder cell is applied to the design of several 8-bit array multipliers, namely a Braun array multiplier, a CSA multiplier, and Baugh–Wooley multipliers. The multiplier circuits are designed using DSCH2 VLSI CAD tools and their layouts are generated by Microwind 3 VLSI CAD tools. The output parameters such as propagation delay, total chip area, and power dissipation are calculated from the simulated results. We have also calculated energy per instruction (EPI), throughput, latency, signal-to-noise ratio (SNR), and the effect of temperature on the drain current by using the generated layout output parameter of a BSIM 4 advanced analyzer. The simulated results of the proposed adder-based multiplier circuit are compared with a cell multiplier that utilizes a MCIT-based adder, a cell multiplier composed of complementary pass transistor logic-based (CPL) adders and those of other published multipliers circuits. From the analysis of these simulated results, it was found that the proposed multiplier circuit gives better performance in terms of power, propagation delay, latency and throughput than other published results.     

Application of photoconductivity decay and photocurrent generation methods for determination of minority carrier lifetime in silicon

Minority carrier lifeline, τ, is one of the most important parameters which has a decisive effect on the performance of silicon devices based on excess carriers. The value of τ is greatly affected by the presence of impurities and defects in silicon and its value provides a fair indication of quality of the material. Photoconductivity decay (PCD) and photocurrent generation (PCG) methods are simple and low cost methods of measurement of minority carrier lifetime in silicon wafers. However, their application requires care. The PCD method can give quite misleading results in case of polycrystalline wafers if there exists potential barriers at the grain boundaries which may affect majority carrier mobility significantly. PCG needs creation of an inducedp ₊-p-n ₊ structure of substantially good quality that should not degrade with time. For PCG method the T measurement under vacuum conditions provides correct and consistent results.     

Effect of Ethrel and 1-methylcyclopropene (1-MCP) on antioxidants in mango (Mangifera indica var. Dashehari) during fruit ripening

Ripening affects the quality and nutritional contents of fleshy fruits. Mango, a climacteric fruit, is very susceptible to post-harvest losses, due to fast softening. In the present paper we report the effect of 1-methylcyclopropene (1-MCP) and Ethrel on antioxidant levels in mango fruit during ripening. Use of 1-MCP is applied commercially to delay ripening while Ethrel is used to accelerate ripening of climacteric fruits. 1-MCP treatment led to decreased levels of H₂O₂ and lipid peroxidation, concomitant with increased activities and isozymes of catalase (CAT) and superoxide dismutase (SOD), as compared to respective controls. On the other hand, Ethrel treatment led to an increase in H₂O₂ and lipid peroxidation, concomitant with a decrease in the activities and isozymes of catalase and SOD. Guaiacol peroxidase (GPX) could not be detected in the control or in treated fruits. Activity of ascorbate peroxidase (APX) was found to drastically increase in the presence of Ethrel while 1-MCP treatment led to only a marginal increase in APX.     

Dimensional analysis of performance of a solar-cum-wind aspirator developed at ciae

Air flow through a solar-cum-wind aspirator is induced by both thermal buoyancy and wind effects. A similitude study has been conducted to characterize air flow rates through solar-cum-wind aspirators. A relationship between the air flow rate and height and diameter of the aspirator, wind speed, temperature rise inside the stack, and relevant air properties has been developed on the basis of the experimental data collected under field conditions.     

Cost analysis of a two unit priority standby system with imperfect switch and arbitrary distributions

This paper deals with cost analysis of a single server two-unit (one priority and the other ordinary) cold standby system with two modes—normal and total failure. A switch is used to operate the standby unit (ordinary) and it works successfully with known probability p( = 1 ? q). Priority unit gets preference both for operation and repair. Failure and repair time distributions are arbitrary. System fails when switch or both the units fail totally. The system is observed at suitable regenerative epochs in order to obtain reliability characteristics of interest to system designers and operations managers. Explicit results for the exponential time distributions have been obtained in particular cases.     

Determination of fibre-matrix interfacial properties in ceramic-matrix composites by a fibre push-out technique

A simple concentric cylinder model is developed for the fibre push-out test in order to interpret the experimentally observed indenter load-displacement curves in ceramic-matrix composites. The fibre-matrix interface is assumed to be partially bonded and partially frictionally coupled. It is shown that a slope change in the loading curve corresponds to bonding at the fibre-matrix interface. In contrast an insignificant change in the slope is predicted for composites in which the fibre-matrix interface is frictionally coupled. This model also provides a framework for determining the interfacial debond energy and the interfacial shear strength in ceramic composites using the fibre push-out tests. The predictions of this model are compared with the push-out test results performed on zircon-SiC composites uniaxially reinforced with either uncoated or BN-coated SiC monofilaments, which suggested that the fibre-matrix interfaces in both of these composites are frictionally coupled.     

Evaluation of Mangosteen juice blend on biomarkers of inflammation in obese subjects: a pilot, dose finding study

Background  

The ability to reduce inflammation in overweight and obese individuals may be valuable in preventing the progression to metabolic syndrome with associated risks for heart disease and diabetes. The purpose of this study was to evaluate the effect of multiple dosages of a proprietary Mangosteen Juice blend on indicators of inflammation and antioxidant levels in obese patients with elevated C-reactive protein (CRP) levels.     

Mobility and distribution of cadmium, nickel and zinc in contaminated soil profiles from Bangladesh

We investigated the mobility and distribution of cadmium (Cd), nickel (Ni) and zinc (Zn) in four contaminated soil profiles from Bangladesh. The sources of contamination of these profiles were tannery wastes, city sewage and the wastes of pharmaceutical and paper mill factories at different locations in Bangladesh. The samples were collected from the A-, B- and C-horizons of each profile: two sub-samples from the A-horizon at depths of 0–5 cm (A1) and >5 cm (A2), and one sample each from the B- and C-horizons. Soil samples were analysed for total metal content by dissolution in aqua regia followed by sequential extraction of the fractions based on their varying solubility. There were six operationally defined groups of extraction sequences: water soluble (F1), exchangeable (F2), carbonate (F3), oxide (F4), organic (F5) and residual (F6). The total concentration of Cd, Ni and Zn in the A-horizon (0–5 cm) ranged from 0.10 to 0.62, from 31 to 54 and from 85 to 838 mg kg⁻¹, respectively. In the B- and C-horizons, the concentrations of these metals decreased many fold, particularly in the city sewage profile where the decrease for Cd and Zn was approximately fourfold. The distribution of metals among the chemical fractions depended on their total concentrations. In the A1-horizon, Cd had the highest mobility factor [MF = (F1+F2+F3)/(F1+F2+F3+F4+F5+F6) × 100] at 41–43% and Ni had the lowest at 3–13%, while Zn, showed intermediate values at 8–25%. The MF decreased with depth in all soil profiles. Among the fractions, the residual fraction contained the lowest levels of Cd but the highest levels of Ni and Zn. This state affected their relative mobility and distribution in soil profiles. Of the soil profiles, the mobility of all metals was higher in the city sewage soil than in any of the other three soils investigated, suggesting that the former may create a health risk by contaminating agricultural products and ground water as it also contained higher amounts of Cd and Zn.