Biodeterioration of sandstone under the influence of different humidity levels in laboratory conditions

Excessive moisture in building materials supports microbial growth. It has been referred that relative humidity more than 55% promotes the microbial growth. To test the effect of different relative humidity tropical chamber test was set up at 52%, 76%, 85% and 96% RH and maximum diversity of fungi was found at 85% and 96% RH. Two fungi Aspergillus sydowi and Aspergillus flavipes were present throughout the course of study from moderate to highly abundant form. It was observed that Fusarium moniliforme, Cephalosporium acremonium, Papulospora sp. proliferated at higher relative humidity (i.e. at 85% and 96.6% RH) and Fusarium roseum, Fusarium oxysporum only at 96% RH level. The relative humidity level lower than 62%, i.e. at 52% level exhibited no fungal growth on sandstone surface during two-year observations. During the study pattern it was noticed that diversity decreased gradually and dominance of particular species increased with the time factor. Analysis of sandstone after fungal colonization by X-ray diffraction and SEM showed the formation of newly formed biomineral.     

Lead decline in the Indian environment resulting from the petrol-lead phase-out programme

Recently, the lead content of various environmental components has decreased in response to replacement of leaded petrol by unleaded petrol. In India, 15 research studies are here assessed with respect to lead concentrations in various environmental components during the leaded petrol phase (before 1996), the transitional phase (1996-2000) and the unleaded petrol phase (2000 onwards). The Ganga River Water exhibited a decrease in lead concentration from 18.0 microg/l in 1988 to 3.1 microg/l in 2001. In Lucknow urban centre, mean lead concentrations in the urban air decreased from 1.6 microg/m(3) in 1994 to 0.2 microg/m(3) in 2002. Lead concentrations in Dalbergia sissoo tree leaves also decreased from 18.7 microg/g dry wt. in 1994 to 8.3 microg/g dry wt. in 2004. Mean blood-lead levels of children from Mumbai, Chennai, Bangalore, Amritsar and Lucknow urban centres have fallen from 18.1 microg/dl in the leaded petrol phase to 12.1 microg/dl in the unleaded petrol phase. The petrol-lead phase-out effort in India has reduced lead concentrations in the various environmental components after 2000. It will help to reduce the exposure of millions of people to environmental lead.     

Multiscale hierarchical analysis of rock mass and prediction of its mechanical and hydraulic properties

Engineering geological and hydro-geological characteristics of foundation rock and surrounding rock mass are the main factors that affect the stability of underground engineering. This paper presents the concept of multiscale hierarchical digital rock mass models to describe the rock mass, including its structures in different scales and corresponding scale dependence. Four scales including regional scale, engineering scale, laboratory scale and microscale are determined, and the corresponding scale-dependent geological structures and their characterization methods are provided. Image analysis and processing method, geostatistics and Monte Carlo simulation technique are used to establish the multiscale hierarchical digital rock mass models, in which the main micro- and macro-structures of rock mass in different geological units and scales are reflected and connected. A computer code is developed for numerically analyzing the strength, fracture behavior and hydraulic conductivity of rock mass using the multiscale hierarchical digital models. Using the models and methods provided in this paper, the geological information of rock mass in different geological units and scales can be considered sufficiently, and the influence of downscale characteristics (such as meso-scale) on the upscale characteristics (such as engineering scale) can be calculated by considering the discrete geological structures in the downscale model as equivalent continuous media in the upscale model. Thus the mechanical and hydraulic properties of rock mass may be evaluated rationally and precisely. The multiscale hierarchical digital rock mass models and the corresponding methods proposed in this paper provide a unified and simple solution for determining the mechanical and hydraulic properties of rock mass in different scales.     

Ferrofluid Lubrication of a Journal Bearing Considering Cavitation

Ferrohydrodynamic lubrication in journal bearings by considering cavitation boundary conditions is studied. It is assumed that the magnetization vector is not parallel to the magnetic field vector. Various bearing characteristics have been studied and it is seen that qualitative behavior of these characteristics remains similar to that in the case of non-ferromagnetic fluid. However, a significant quantitative enhancement of these characteristics is observed.     

RAPID ONLINE MONITORING OF A HETEROGENEOUS CATALYST BY A PULSED REACTOR COUPLED TO GC-MS

A rapid screening system for heterogeneous catalyst discovery has been developed by coupling an in-house designed and fabricated high temperature vapor phase pulse reactor on-line to a GC-MS. The incorporation of gas chromatography for separation of the products with the mass spectrometry system allowed simultaneous identification and determination of reaction products and substrate conversion. This system was employed to study the vapor phase catalytic hydride transfer reduction (CHTR) of nitrobenzene with methanol as hydrogen donor on an MgO catalyst as a model reaction. Structural information of all the by-products that were formed was useful to understand the reaction mechanism. The products obtained with the new screening technique were in good agreement with conventional bench scale experiments. The rapid online screening provided an efficient methodology for optimization of reaction conditions such as catalyst loading, reaction temperature, and mole ratios. Response Surface Methodology (RSM) was used to optimize the conversion of reactants and selectivity of products.     

Multitrack Staining Apparatus with High Resolution and Time-Lapsed Acquisition for Polyacrylamide Gels

Polyacrylamide gel electrophoresis (PAGE) is commonly used for the separation, identification, and purification of mixtures of proteins and nucleic acids. A suitable staining method for the polyacrylamide gels is imperative to determine low concentrations of resolved macromolecules. Several staining methods have been adopted; ethidium bromide, silver, and coomassie staining are the most frequently employed. Silver staining determines macromolecules at nanomolar concentrations but involves many steps and thus is tedious for multiple gels in parallel. In this article, a simple multitrack laboratory-constructed silver staining apparatus is characterized that may enhance the sensitivity of the electrophoresis stains and the homogeneity of detection. In addition, the low cost and simplicity of this system provide wide applicability for gel electrophoresis.     

Newtonian quantitative elastohydrodynamic film thickness with linear piezoviscosity

Examples are provided for linear pressure-viscosity response at low pressures, which are said to exist in the concentrated contact inlet, including lubricants at high temperature, low viscosity liquids and water/glycol solutions. Full isothermal, Newtonian simulations of the EHL problem reveal film-forming, which is quite similar to that of exponential liquids with the exception of the reduced sensitivity to the Dowson material parameter, G, or the Moes parameter, L. Film thickness formulas are offered, which have been experimentally validated. In a significant departure from most investigations of this kind, the viscosity of the experimental liquids was not adjusted to provide successful comparisons with measurement.     

Control chart pattern recognition using feature-based learning vector quantization

The reported learning vector quantization (LVQ) network-based control chart pattern (CCP) recognizers in literature use raw process data as the input vector and can recognize six basic CCPs only. In this paper, an LVQ network-based CCP recognizer is presented that can recognize eight basic CCPs, using seven extracted shape features from the pattern data as the input vector. The recognition performance of this recognizer is compared with the LVQ network-based recognizer that uses raw process data as the input vector. The results show that the feature-based recognizer results in substantially better recognition performance than the raw data-based recognizer. The confusion matrix reveals that the recognition performance of the feature-based recognizer can be improved further if any feature that is more powerful in discriminating shift and trend pattern can be identified. Comparison of performances of LVQ network-based and multilayer perceptrons (MLP) network-based recognizers (both using extracted features as input vector) reveals that the LVQ network-based recognizer requires much lesser learning time than the MLP network-based recognizer, but results in little inferior recognition performance.     

Influence of thermal insulation and wind velocity on the SMA actuator for morphing applications

This paper presents the modeling and simulation of shape memory alloy (SMA) wire actuators for morphing micro air vehicles (MAVs) when exposed to high-velocity wind during flight. The specific operating conditions include thermal insulation, varying convective heat-transfer coefficients due to wind velocity, aerodynamic loads, and operation from MAV battery. Application-oriented modeling parameters were determined from a flyable morphing MAV. The simulation could dynamically generate the morphing angle as a function of the electrical input pulse duty cycle. The model showed that compared with 10 % duty cycle, a 25 % duty cycle achieves an energy saving of 33 % and an increase in actuation speed of 3.7 times. Further, increasing the duty cycle has a negligible improvement in energy saving, but the actuation rate is increased by 15.8 times. The SIMULINK® model, which was validated through the ground test, would help in the design of SMA actuators and controllers for aerospace vehicles and automobiles.

     

Response of serum minerals (calcium,phosphate, and magnesium) and endocrine glands (calcitonin cells and parathyroid gland) of wistar rat after chlorpyrifos administration

Wistar rats (male) were daily administered chlorpyrifos at a dose of 5 mg/kg b wt. and 10 mg/kg b wt. and sacrificed on 1st, 2nd, 4th, 6th, and 8th week. In chlorpyrifos exposed rats hypocalcemia, hypophosphatemia and hypomagnesemia were recorded. At later intervals an increased levels of serum calcium and phosphate were observed. The parathyroid glands and calcitonin cells exhibited increased activity which is evident by increased nuclear volume of these cells. Microsc. Res. Tech. 76:673–678, 2013. © 2013 Wiley Periodicals, Inc.