Room temperature ferromagnetism in Co doped ZnO within an optimal doping level of 5%

We report on the structural, micro-structural and magnetic properties of Zn_1?xCo_xO (0 ≤ x ≤ 0.1) system. Electron probe micro-structural analysis on 5% Co doped ZnO indicates the presence of segregated cobalt oxide which is also confirmed from the Co 2p core level X-ray photoelectron spectrum. The presence of oxygen defects in lower percentage of Co doped ZnO (≤5%) enhances the carrier mediated exchange interaction and thereby enhancing the room-temperature ferromagnetic behaviour. Higher doping percentage of cobalt (>5%) creates weak link between the grains and suppresses the carrier mediated exchange interaction. This is the reason why room temperature ferromagnetism is not observed in 7% and 10% Co doped ZnO.     

Two-Dimensional Analysis of Dam-Break Flow in Vertical Plane

This work presents numerical computations for the analysis of Dam-Break Flow using two-dimensional flow equations in a vertical plane. The numerical model uses the general approach of the simplified marker and cell method combined with the volume of fluid approach for the surface tracking. The time evolution of flow depth at the dam site and the evolution of the pressure distribution are investigated for both wet and dry bed conditions. The effect of the initially nonhydrostatic state on the long term surface profile and wave velocity are studied. These long term effects are found to be marginal in the case of wet-bed conditions, but are significant in dry-bed conditions. The dry-bed tip velocity immediately after the dam break, computed numerically, compares well with analytical results published previously. The time taken to obtain a constant flow depth at the dam site increases with decreasing initial depth ratio. The numerical result for this time elapse for dry-bed conditions is close to the experimentally obtained value.     

Postharvest Hardness and Color Evolution of White Button Mushrooms (Agaricus bisporus)

ABSTRACT: The quality evaluation of mushrooms was studied by storing fresh white button mushrooms (Agaricus bisporus) for 6 to 8 d, at various controlled temperature conditions (3.5 to 15 °C) and measuring the instrumental textural hardness and color of the mushroom cap for different product batches. A nonlinear mixed effect Weibull model was used to describe mushroom cap texture and color kinetics during storage considering the batch variability into account. Storage temperature was found to play a significant role in controlling texture and color degradation. On lowering storage temperature (i) the extent of the final browning extent in the mushroom after storage was reduced and (ii) the rate textural hardness losses was slowed down. A linear dependence of the final browning index with temperature was found. An Arrhenius type relationship was found to exist between the temperature of storage and storage time with respect to textural hardness. The average batch energy of activation was calculated to be 207 ± 42kJ/mol in a temperature range of 3.5 to 20 °C. Practical Application: This article evaluates how temperature abuse affects mushroom texture and color, applying methods that allow for the consideration of the natural product variability that is inherent in mushrooms. Its results apply to mushroom producers, retail distribution, and supermarkets for effective storage management.     

A methodology for the assessment of nuclear power development scenario

The International Atomic Energy Agency (IAEA) has initiated an International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) in the year 2000. The main objective of INPRO is to help the world community to ensure that clean and safe nuclear energy is available to contribute in fulfilling the energy needs in the 21st century in a sustainable manner. This paper demonstrates a methodology as an application of INPRO assessment for constructing nuclear power development scenarios by the use of IAEA energy optimisation models MESSAGE and DESAE. The scenario for the overall growth of energy and electricity in India is considered as a case study since for several decades India is vigorously pursuing nuclear power development program to meet its growing energy needs. It is evident from this study that in order to develop a realistic nuclear power scenario, it is necessary to generate an overall energy and electricity scenario at first. Within the overall energy-electricity picture it can be envisaged how the nuclear power technology would contribute to supply the future energy needs.     

Efficient admission control algorithms for multimedia servers

In this paper, we have proposed efficient admission control algorithms for multimedia storage servers that are providers of variable-bit-rate media streams. The proposed schemes are based on a slicing technique and use aggressive methods for admission control. We have developed two types of admission control schemes: Future-Max (FM) and Interval Estimation (IE). The FM algorithm uses the maximum bandwidth requirement of the future to estimate the bandwidth requirement. The IE algorithm defines a class of admission control schemes that use a combination of the maximum and average bandwidths within each interval to estimate the bandwidth requirement of the interval. The performance evaluations done through simulations show that the server utilization is improved by using the FM and IE algorithms. Furthermore, the quality of service is also improved by using the FM and IE algorithms. Several results depicting the trade-off between the implementation complexity, the desired accuracy, the number of accepted requests, and the quality of service are presented.     

Illumination normalized based technique for retinal blood vessel segmentation

The Retinal image carries important information about the health of the sensory part of the visual system. In this paper, a new approach is suggested by utilizing the homomorphic filter integrated with Contrast limited adaptive histogram equalization (CLAHE) method for the illumination normalization and contrast enhancement of the retinal images. Then segmentation is done through several steps by using the existing methods such as morphological filtering, a second derivative operator that is followed by a final morphological filtering stage and hysteresis thresholding. The suggested method is verified on DRIVE and CHASE‐DB1 databases and has average accuracy of 72.03% and 64.54%, accordingly. The obtained results demonstrate that the proposed approaches achieve higher accuracy than the traditional method. The suggested approach not only contributes to the successful result, but also minimizes the computing time.     

Facile synthesis,morphological, structural,photocatalytic, and optical properties of ZnFe2O4 nanostructures

Spinel ferrite ZnFe₂O₄ nanostructures have been prepared as sunlight responsive photocatalysts via facile co-precipitation method. The structural, morphological, and optical responses were diligently characterized using XRD, Raman spectroscopy, FESEM, and UV–Vis absorption spectroscopy, respectively. FESEM studies revealed nanoparticles and porous-like nanoparticle aggregates, found to be of cubic spinel ZnFe₂O₄ from XRD and Raman studies. Crystallite size varied from 5 to 13.6 nm, whereas band gap changed from 1.89 to 1.95 eV with CTAB concentration variation. ZnFe₂O₄ nanostructures were employed for sunlight-assisted photodegradation of organic pollutants such as MB, MG, and MO dyes in water. The synthesized ZnFe₂O₄ nanoparticle aggregates with porous-like morphology with crystallite size of 9.2 nm showed superior photocatalytic response and decomposed 80.4% of MB dye in only 40 min. The superiority of the porous-like ZnFe₂O₄ nanoparticle aggregates was mainly ascribed to its optimal crystallite size, narrower band gap, and improved sunlight utilization efficiency. A plausible mechanism of photocatalytic oxidation of dye supported by scavenger studies has also been proposed. The synthesized ZnFe₂O₄ nanostructures have easy magnetic recycling property along with excellent photocatalytic capability and hold potential for the treatment of contaminated water.

     

Regional Specialisation for Technological Innovation in R&D Laboratories: A Strategic Perspective

The present paper attempts to highlight the strategy of regional specialisation for technological innovation in R&D laboratories. The paper makes a proposition that regional specialisation should be recognised as a strategic initiative for technology development in R&D laboratories. The rationale for this strategic initiative has been substantiated with the help of illustrations from the cases of technology development efforts taken up in different laboratories in the country under the Council of Scientific and Industrial Research (CSIR), India. In this direction, CSIR and other centres of excellence have played a pioneering role in the development of various industrial clusters and artisan concentrations in different parts of the country. The implications of adoption or otherwise of this strategy initiative for technological innovation in R&D laboratories have been discussed.