Delineation of Groundwater Potential Zones of Coastal Groundwater Basin Using Multi-Criteria Decision Making Technique

Delineation of groundwater potential zones (GWPZ) has been performed for a coastal groundwater basin of eastern India. The groundwater potential zone index (GWPZI) map is generated by using Analytic Hierarchy Process (AHP) from different influencing features, e.g., Land Use/Land Cover (LU/LC), soil (S), geomorphology (GM), hydrogeology (HG), surface geology (SG), recharge rate (RR), drainage density (DD), rainfall (RF), slope (Sl), surface water bodies (SW), lineament density (LD), and Normalized Difference Vegetative Index (NDVI). Recharge rate values are estimated from hydrological water balance model. Overlay weighted sum method is used to integrate all thematic feature maps to generate GWPZ map of the study area. Four zones have been identified for the coastal groundwater basin [very good: 36.39 % (273.53 km², good: 43.57 % (327.47 km²), moderate: 18.27 % (137.30 km²), and poor: 1.77 % (13.27 km²)]. Areas in north to south-west and south-east direction show very good GWPZ due to the presence of low drainage density. GWPZ map and well yield values show good agreement. Sensitivity analysis reveals that exclusion/absence of rainfall and lineament density increases the poor groundwater potential zones. Omission of hydrogeology, soils, surface geology, and NDVI show maximum increase in good GWPZ. Obtained GWPZ map can be utilized effectively for planning of sustainable agriculture. This analysis demonstrates the potential applicability of the methodology for a general coastal groundwater basin.     

GAS-LIQUID REACTION KINETICS: A REVIEW OF DETERMINATION METHODS

The aim of this article is to provide comprehensive insight into the determination and interpretation of reaction kinetics of two-phase (gas-liquid) systems. Various aspects of the methodologies used for the measurements of kinetic parameters (such as equipment design, corresponding theoretical background, main steps, advantages, and limitations) are discussed in detail. In addition, an illustrating example is provided based on an industrially relevant absorption system.     

Robot calibration using an automatic theodolite

The Vision Based Automatic Theodolite (VBAT) is an automatic partial pose measurement system for robot calibration. It uses low resolution rotation stages and resolution enhancement from a vision system to determine the line-of-sight to a spherical illuminated target. Automatic tracking, focusing, and centring provide the calibration system with speed, reliability, and repeatability. A kinematic model of the VBAT is described which includes both the mechanical parts of the system and the optics, using a modified Denavit-Hartenberg approach. All parameters in the VBAT model are identified and embedded into the system controller producing an instrument of 2 arc second accuracy. The system is then used in a conventional manner to calibrate a six degree of freedom PUMA robot, and the results compared to another calibration of the same arm by a coordinate measuring machine with repeatability and accuracy of 0.02 mm. The calibration using the VBAT enhances the accuracy of the PUMA to within 0.2 mm of that produced by the CMM calibration, compared to an accuracy of 14 mm prior to calibration.     

Bacterial population changes in hospital effluent treatment plant in central India

Hospital effluent with its high content of multidrug resistant (MDR) enterobacteria and the presence of enteric pathogens could pose a grave problem for the community. It was planned at our tertiary care hospital in central India to study the population changes at various steps of effluent treatment plant (ETP) like collection, aeration, clarification, liquid sludge, dried sludge, high-pressure filter and treated wastewater. The study included viable bacterial counts, coliform counts, staphylococcal, enterococcal, Pseudomonas and multiple drug resistant (MDR) gram negative bacterial counts in the different stages of ETP. In order to study the distribution of bacteria as free floating in liquid and adherent to suspended particles, enumeration of the bacteria in the filterate and the sediment was also carried out. The effluent input showed 55% of the 8.6 x 10(6)/ml bacteria as coliforms and E. coli which was a typical of fecal flora. The prevalence of MDR coliforms was 0.26%. The substantial reduction (> 3log) was seen for the effluent coming from the clarifier. The bulk of the bacteria in the hospital effluent remains firmly adhered to solid particles; aeration and clarification removes bulk of the bacteria by physical processes like flocculation. The treated liquid effluent still contains sizeable loads of MDR bacteria and inactivation by procedure such as chlorination is required. The bacteria get concentrated in sludge and a greater concentration of chlorine is required for decontamination.     

Synthesis of nanocrystalline materials through reverse micelles: A versatile methodology for synthesis of complex metal oxides

We have been successful in obtaining monophasic nanosized oxides with varying chemical compositions using the reverse micellar method. Here we describe our methodology to obtain important metal oxides like ceria, zirconia and zinc oxide. The oxalate of cerium, zirconium and zinc were synthesized using the reverse micellar route. While nanorods of zinc oxalate with dimension, 120 nm in diameter and 600 nm in length, could be obtained, whereas spherical particles of size, 4–6 nm, were obtained for cerium oxalate. These precursors were heated to form their respective oxides. Mixture of nanorods and nanoparticles of cerium oxide was obtained. ZrO₂ nanoparticles of 3–4 nm size were obtained by the thermal decomposition of zirconium oxalate precursor. ZnO nanoparticles (55 nm) were obtained by the decomposition of zinc oxalate nanorods. Photoluminescence (PL) studies at 20 K shows the presence of three peaks corresponding to free excitonic emission, free to bound and donor-acceptor transitions. We also synthesized nanoparticles corresponding to Ba_1−x Pb _x ZrO₃ using the reverse micellar route. The dielectric constant and loss were stable with frequency and temperature for the solid solution.     

Reliability analysis of mining equipment: A case study of a crushing plant at Jajarm Bauxite Mine in Iran

The performance of mining machines depends on the reliability of the equipment used, the operating environment, the maintenance efficiency, the operation process, the technical expertise of the miners, etc. As the size and complexity of mining equipments continue to increase, the implications of equipment failure become ever more critical. Therefore, reliability analysis is required to identify the bottlenecks in the system and to find the components or subsystems with low reliability for a given designed performance. It is important to select a suitable method for data collection as well as for reliability analysis. This paper presents a case study describing reliability and availability analysis of the crushing plant number 3 at Jajarm Bauxite Mine in Iran. In this study, the crushing plant number 3 is divided into six subsystems. The parameters of some probability distributions, such as Weibull, Exponential, and Lognormal distributions have been estimated by using ReliaSoft's Weibull++6 software. The results of the analysis show that the conveyer subsystem and secondary screen subsystem are critical from a reliability point of view, and the secondary crusher subsystem and conveyer subsystem are critical from an availability point of view. The study also shows that the reliability analysis is very useful for deciding maintenance intervals.     

Thermal stresses in aluminum 6061 and nylon 66 long fiber thermoplastic (LFT) composite joint in a tailcone

The present paper involves a metal/polymer joint in a tailcone in a kinetic energy penetrator (KEP), one of the ammunition types used by the military. It is currently made of aluminum 7075 alloy, which could be partly replaced by long fiber thermoplastic (LFT) composite. Two different types of aluminum insert geometries were considered, viz., beaded and threaded. Thermal stresses set in during cooling of the tailcone from the processing temperature mainly because of the difference in the values of coefficients of thermal expansion and differential cooling between the aluminum and the LFT composite. Finite element (FE) modeling was done to predict the temperature profile during the cooling of the tailcone from the processing temperature. FE results showed that the LFT composite part of the tailcone cooled faster than the aluminum insert. Experimental verification of this temperature profile was obtained by infrared (IR) thermography. Based on the temperature profile, thermal stresses at the metal/LFT composite interface were estimated using an FE model. Different magnitudes of thermal stresses were present at the aluminum/LFT composite interface owing to the nature of distribution of fibers around the insert. Magnitude of thermal stresses in the case of a beaded insert was approximately 2.5 MPa whereas in the case of a threaded insert, it was approximately 12 MPa.

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Mimicking the biomineralization of aragonite (calcium carbonate) using reverse-micelles under ambient conditions

Reverse micelles have been used, for the first time, to mimic the conditions suitable for the low-temperature (40 degrees C) synthesis of the high temperature and high pressure orthorhombic phase of calcium carbonate (aragonite) normally crystallizing in the sea as abalone shells and as natural pearls. The aragonite phase undergoes morphological changes under higher temperatures with long Y-junctions (at 40 degrees C) to shorter rod-like structures (at 85 degrees C). Pure calcite is obtained at higher reaction temperature. At a lower temperature (5 degrees C) homogeneous and monodisperse spheres of vaterite is obtained. The spherical particles after longer aging (168 h) aggregate to form nanorods and the self assembly is clearly seen at various stages by electron microscopic images.     

Synthesis of surface-active quaternary amino polyfluorosiloxanes

We report synthesis of surface-active quaternary amino polyfluorosiloxanes. Hydrosilation of silanic hydrogen containing polyfluorosiloxanes with olefinic epoxides, in the presence of a platinum–divinyltetramethyldisiloxane complex gave epoxy polyfluorosiloxanes. These, on further reaction with various amines followed by quaternization, gave quaternary amino polyfluorosiloxanes. The quaternary amino polyfluorosiloxanes reduce surface tension of water to 25 mN/m² at a 25-millimolar concentration. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1700–1708, 2000     

Delayed duplicate acknowledgements: a TCP‐Unaware approach to improve performance of TCP over wireless

Since a TCP sender cannot distinguish between packet losses arising from transmission errors from those due to congestion, TCP tends to perform poorly on wireless links that are prone to transmission errors. Several techniques have previously been proposed to improve TCP performance over wireless links. Existing schemes typically require an intermediate node (typically, a base station) to be TCP‐aware. For instance, the Snoop scheme requires the base station to interpret TCP headers and take appropriate action to help improve TCP performance. This paper proposes an alternative TCP‐unaware technique that attempts to mimic the behavior of the Snoop protocol. Performance evaluation shows that the proposed Delayed Dupacks scheme performs quite well. Copyright © 2001 John Wiley & Sons, Ltd.