Cost analysis of a two-unit standby system under the influence of earthquakes

This paper deals with two models. In model 1, which is cold standby, when an earthquake comes the operation of the unit is stopped. In model 2, which is warm standby, a medium intensity earthquake will cause a short circuit failure mode. The repair is available immediately upon calling. In model 1, the failure rate is taken to be constant whereas the repair time distribution is arbitrary. In model 2, the failure and repair time distributions are considered to be arbitrarily distributed. Applying the regenerative theory in Markov renewal processes, various reliability characteristics of interest have been explicitly obtained.     

Solar energy conversion through phase transformations

Sodium thiosulphate pentahydrate and sodium sulphate decahydrate show appreciable potential differences and currents when the solid phase is in contact with its molten phase. the studies offer a new method for converting solar energy into electrical power.     

Activation status and function of the VLA-4 (alpha4beta1) integrin expressed on human melanoma cell lines

A highly sensitive microspectrophotometer was developed to measure spectral changes of oxyhemoglobin (oxy Hb) in single red blood cells (RBC) incubated with stimulated macrophages as a model of nitric oxide (NO) dependent cytotoxicity. Our microspectrophotometer, using a modified acousto-optic tunable filter (AOTF) and a 2-dimensional CCD array, allows fast spectrophotometric data acquisition. Human RBC treated with various concentrations of NO showed spectral changes due to the conversion of oxy Hb to methemoglobin (met Hb), in which the change in absorption differences at alpha (557 590 nm) and beta (542-525 nm) bands showed a linear relationship with the concentration of NO up to 100 microM. In contrast to highly diffusible NO, nitrite ions (NO2-) seem to enter RBC very slowly, resulting in negligible formation of met Hb in the presence of 5 mM glucose even during a prolonged incubation period. RBC were incubated with murine macrophages with and without lipopolysaccharide (LPS) in the presence of glucose for 24 and 40 h and subjected to the microspectrophotometric assay. The RBC incubated with LPS-stimulated macrophages showed significant changes in the spectrum due to NO-dependent conversion of oxy Hb to met Hb, which corresponded to the spectral changes of RBC treated with a several times higher concentration of NO than that in the culture medium. The trapping efficiency was calculated from the amounts of the NO released from macrophages and of the met Hb formed in the RBC, which gave a high efficiency (43%). The results suggest that RBC trap NO directly by cell cell interaction with macrophages. This spectrophotometric system is available for use with just a few drops of samples to study NO-specific cytotoxicity as a model of RBC without the use of any chemical reagent, in parallel with microscopic observations on changes of the cellular morphology under physiological conditions, such as membrane damage leading to hemolysis, adherence, and phagocytosis.     

Climate and built environment studies in universities — an Australian experience

Climate and built environment studies in Australian Universities, especially in the University of Queensland, are reviewed. By using examples of work in the tropical regions of Northern Australia and the Pacific Islands, current programmes which concern building and planning for communities with different cultural backgrounds are explained. A case is made for university studies which emphasise the integration of the natural and social sciences.     

Lattice Anomalies in (La,Sr)2CuO4 Under Epitaxial Strain Probed by Polarized X-Ray Absorption Spectroscopy

Local lattice anomalies in optimally doped T-(La,Sr)₂CuO₄ single crystal like thin films (T _c?=?43.4 K) grown by molecular-beam epitaxy have been studied by the in-plane polarized Cu K-edge extended X-ray absorption fine structure (EXAFS). The results indicate temperature-dependent local atomic displacements which are anomalous at the T _c and below a higher temperature T _s as demonstrated by a change in the mean square relative displacement of the Cu–O bond $\sigma _{{\rm Cu}-{\rm O}}^2$ , i.e., a sharp drop at the T _c and a gradual deviation from a noncorrelated Debye-like behavior below T _s where the spatial inhomogeneity appears. We find that the magnitude of the Cu–O displacement changes at the T _c, $\Delta \sigma _{{\rm Cu}-{\rm O}}^2$ is enhanced by compressive strain while the tendency of charge segregation is suppressed. The results suggest that the uniaxial pressure effects stabilize the system by decreasing the onset temperature and magnitude of spatial heterogeneity.     

OVSF Code Sharing and Reducing the Code Wastage Capacity in WCDMA

The non quantized nature of user rate wastes the code capacity in Orthogonal Variable Spreading Factor Codes (OVSF) based Code Division Multiple Access (CDMA) systems. The code sharing scheme in multi code CDMA is proposed to minimize the code rate wastage. The scheme combines the unused (wastage) capacity of already occupied codes to reduce the code blocking problem. Simulation results are presented to show the superiority of the proposed code assignment scheme as compared to existing schemes.

Peak load forecasting using Bayesian regularization,Resilient and adaptive backpropagation learning based artificial neural networks

Up to 7 days ahead electrical peak load forecasting has been done using feed forward neural network based on Steepest descent, Bayesian regularization, Resilient and adaptive backpropagation learning methods, by incorporating the effect of eleven weather parameters and past peak load information. To avoid trapping of network into a state of local minima, the optimization of user-defined parameters viz., learning rate and error goal has been performed. The sliding window concept has been incorporated for selection of training data set. It was then reduced as per relevant selection according to the day type and season for which the forecast is made. To reduce the dimensionality of input matrix, the Principal Component Analysis method of factor extraction or correlation analysis technique has been used and their performance has been compared. The resultant data set was used for training of three-layered neural network. In order to increase the learning speed, the weights and biases were initialized according to Nguyen and Widrow method. To avoid over fitting, early stopping of training was done at the minimum validation error.     

Evaluation of Robustness of the Biosurfactant Derived from Balanites aegyptiaca (L.) Del.

Balanites aegyptiaca (L.) Del. is a widely distributed xerophytic multipurpose tree. The mesocarp of the fruit of B. aegyptiaca has detergent properties due to the presence of saponins. The stability potential of this biosurfactant at varying pH, temperature, and salinity has not been explored so far. In the present study, the relative surface tensions of five different concentrations of the biosurfactant were studied at different temperatures, salinity, and under pH conditions. This study reveals that this biosurfactant retains its activity over a wide range of pH (3–11) and at high salinity (7% NaCl). It is a thermostable cationic surfactant; surfactant activity was recorded even at 100 °C with the lowest relative surface tension of 0.47. High oil displacement (18.00 mm) was observed when studied with petrol. This biosurfactant was found to have a high emulsification index (E₂₄) of 70% with mustard oil. These results indicate that biosurfactant derived from B. aegyptiaca may find use in a wide range of sectors such as textile, food, cosmetics, oil recovery, and healthcare under a wide range of physical and chemical conditions. It offers an efficient, economically viable, and plant-derived alternative to synthetic detergents and adds a way to maintain a sustainable environment.     

Enhanced endoglucanase production by soil inhabiting Streptomyces sp. strain NAA9 using lignocellulosic biomass

The actinomycete strain NAA9 exhibiting cellulase production potential was identified based on 16S rDNA sequencing and was found belonging to Streptomyces group. On studying the effect of different lignocellulosic biomass on cellulase production by Streptomyces sp. NAA9, Parthenium hysterophorus weed biomass induced highest levels of enzyme production. The enzyme production was further enhanced by optimization of various parameters, under submerged fermentation conditions. The optimized conditions of 2% (w/v) substrate concentration, 40°C temperature, pH 6.0, an incubation period of 6 days and supplementation of the medium with 0.5% ammonium sulfate, resulted in maximum 0.990±0.012 U/ml endoglucanase production. The findings demonstrate the improved cellulase production by Streptomyces strain NAA9 using P. hysterophorus and indicate the potential of this weed biomass in acting as a low-cost natural substrate for cellulase production. The enzyme produced by actinomycete strain can also be utilized in various applications based on the bioconversion of the cellulosic biomass.