The Irradiation Performance and Microstructural Evolution in 9Cr-2W Steel Under Ion Irradiation

Grade 92 steel (9Cr-2W) is a ferritic-martensitic steel with good mechanical and thermal properties. It is being considered for structural applications in Generation IV reactors. Still, the irradiation performance of this alloy needs more investigation as a result of the limited available data. The irradiation performance investigation of Grade 92 steel would contribute to the understanding of engineering aspects including feasibility of application, economy, and maintenance. In this study, Grade 92 steel was irradiated by iron ion beam to 10, 50, and 100 dpa at 30 and 500 °C. In general, the samples exhibited good radiation damage resistance at these testing parameters. The radiation-induced hardening was higher at 30 °C with higher dislocation density; however, the dislocation density was less pronounced at higher temperature. Moreover, the irradiated samples at 30 °C had defect clusters and their density increased at higher doses. On the other hand, dislocation loops were found in the irradiated sample at 50 dpa and 500 °C. Further, the irradiated samples did not show any bubble or void.     

A conducting composite based on poly(N‐vinylcarbazole)–formalin resin and acetylene black

A poly(N‐vinylcarbazole) (PNVC)–formalin (FO) resin (PNVC‐FO) was prepared via copolycondensation between N‐vinylcarbazole (NVC) and FO in the presence of dry HCl gas in toluene medium at 110°C. A highly conducting composite of PNVC‐FO resin with nanodimensional acetylene black (AB) was prepared by carrying out the polycondensation reaction in presence of a suspension of acetylene black (AB) in toluene. The inclusion of PNVC in the PNVC‐FO‐AB composite was confirmed by FT‐IR analysis. Scanning electron microscopic analyses of PNVC‐FO resin and PNVC‐FO‐AB composite revealed formation of spherical particles and aggregates of irregular shapes respectively. Thermogravimetric analyses revealed the overall stability order as: AB > PNVC‐FO‐AB composite > PNVC‐FO resin > PNVC homopolymer. In sharp contrast to PNVC and PNVC‐FO resin, which were both nonconducting (10^?12 to 10^?16 S/cm), the conductivity of the composites reached values between 0.75 S/cm and 6.54 S/cm corresponding to AB loading of 28–49 wt % respectively. Temperature versus conductivity studies revealed an initial increase in conductivity upto 200°C and current–voltage characteristics of the PNVC‐FO‐AB composite showed a linear trend consistent with Ohmic behavior. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3837–3843, 2007     

Estimation of gross calorific value of coals using artificial neural networks

The gross calorific value (GCV) is an important property defining the energy content and thereby efficiency of fuels, such as coals. There exist a number of correlations for estimating the GCV of a coal sample based upon its proximate and/or ultimate analyses. These correlations are mainly linear in character although there are indications that the relationship between the GCV and a few constituents of the proximate and ultimate analyses could be nonlinear. Accordingly, in this paper a total of seven nonlinear models have been developed using the artificial neural networks (ANN) methodology for the estimation of GCV with a special focus on Indian coals. The comprehensive ANN model developed here uses all the major constituents of the proximate and ultimate analyses as inputs while the remaining six sub-models use different combinations of the constituents of the stated analyses. It has been found that the GCV prediction accuracy of all the models is excellent with the comprehensive model being the most accurate GCV predictor. Also, the performance of the ANN models has been found to be consistently better than that of their linear counterparts. Additionally, a sensitivity analysis of the comprehensive ANN model has been performed to identify the important model inputs, which significantly affect the GCV. The ANN-based modeling approach illustrated in this paper is sufficiently general and thus can be gainfully extended for estimating the GCV of a wide spectrum of solid, liquid and gaseous fuels.     

Modification of polyethersulphone induced by high energy proton,C+, and Ne6+ ions: A spectroscopic study

Polyethersulphone (PES) was irradiated with 4 MeV proton, 3.6 MeV C⁺, and 145 MeV Ne⁶⁺ ions at different ion fluences. The linear energy transfer dependence on ion‐induced spectral changes was analyzed by ultraviolet–visible, Fourier transform infrared spectroscopy and fluorescence spectroscopy. The gradual red shift with the increase in optical absorption was observed in the region of 350–500 nm for proton and 400–800 nm for C⁺ and Ne⁶⁺ ions irradiated PES. The gradual shift in absorption may be attributed to the formation of carbonaceous clusters. The gradual decrease in optical band gap indicates increase in cluster sizes. When PES was irradiated with protons, loss in fluorescence emission intensity at 440 nm was observed, although there was no change in spectral shape. In contrast, C⁺ and Ne⁶⁺ ion irradiated PES showed blue shift with concomitant loss in intensity and the formation of new peak at 575 nm. In fact, heavier ions are found to be more effective in inducing physicochemical modifications in PES. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1591–1597, 2006     

A universal fluid cell for the imaging of biological specimens in the atomic force microscope

Recently, atomic force microscope (AFM) manufacturers have begun producing instruments specifically designed to image biological specimens. In most instances, they are integrated with an inverted optical microscope, which permits concurrent optical and AFM imaging. An important component of the set‐up is the imaging chamber, whose design determines the nature of the experiments that can be conducted. Many different imaging chamber designs are available, usually designed to optimize a single parameter, such as the dimensions of the substrate or the volume of fluid that can be used throughout the experiment. In this report, we present a universal fluid cell, which simultaneously optimizes all of the parameters that are important for the imaging of biological specimens in the AFM. This novel imaging chamber has been successfully tested using mammalian, plant, and microbial cells. Microsc. Res. Tech. 76:357–363, 2013. © 2013 Wiley Periodicals, Inc.     

Unsteady natural convection in a triangular enclosure under isothermal heating

The fluid flow and heat transfer inside a triangular enclosure due to instantaneous heating on the inclined walls are investigated using an improved scaling analysis and direct numerical simulations. The development of the unsteady natural convection boundary layer under the inclined walls may be classified into three distinct stages including a start-up stage, a transitional stage and a steady state stage, which can be clearly identified in the analytical and numerical results. A new triple-layer integral approach of scaling analysis has been considered to obtain major scaling relations of the velocity, thicknesses, Nusselt number and the flow development time of the natural convection boundary layer and verified by direct numerical simulations over a wide range of flow parameters.     

Racial variation of factor VII activity and antigen levels and their correlates in healthy Chinese and Indians at low and high risk for coronary artery disease

We examined the genotypes of ALDH2, ADH2, ADH3 and P-4502E1 loci of alcoholics and nonalcoholics. Also we compared the frequencies of the homozygous ALDH2*1/1 genotype and heterozygous ALDH2*1/2 genotypes in alcoholics. Our study reported differences in the allelic frequencies of ALDH2, ADH2 and ADH3 loci between alcoholics and nonalcoholics. For alcoholics, it was indicated that ADH2 and ADH3 plays an important role for alcoholism. For genotypes of P-4502E1, no significant difference was observed between alcoholics and nonalcoholics. Alcoholics with the heterozygous ALDH2*1/2 genotype had significantly higher frequency of the ADH2*1 than that of alcoholics with ALDH2*1/1 genotype. Concerning the alcoholics with the heterozygous ALDH2*1/2 genotype, we assumed that ADH2*1 plays a role for the development of alcoholism.     

The pattern of inflammation in rat sepsis due to enterotoxin-producing Staphylococcus aureus: a comparison with ischemia-reperfusion injury

Sepsis and trauma have similarities in their immunopathologic profiles. Both conditions can result in multi-system organ failure which is sometimes associated with cytokine generation and inflammatory cell activation. Furthermore, decreases in peripheral blood monocyte expression of HLA-DR have been noted in both human sepsis and trauma. However, the magnitude, onset, and time course of such stimuli are often difficult to ascertain in human studies. Thus, to study a more detailed in vivo immunologic profile in these conditions, rat models were employed. Our aim was to describe and analyze cytokine and peripheral blood immunophenotype patterns in bacterially induced rat sepsis and to compare this to rat ischemia-reperfusion injury. Sprague-Dawley rats underwent either bacterial injection with enterotoxin producing Staphylococcus aureus or hind limb ischemia/ reperfusion. Two bacterial doses which were either lethal or sublethal at 24-48 hours were utilized. Peripheral blood neutrophils and B-lymphocytes were studied for expression of beta-integrins (CD11b and CD11b/c) and I-A, respectively, using flow cytometry. Corresponding plasma levels of TNF alpha and interferon gamma were measured by ELISA. At 24 hr, a lethal bacterial lethal bacterial dose injection resulted in significantly higher levels of neutrophil CD11b/c expression (p < 0.005) compared with ischemia-reperfusion treatment. B-cell I-A expression was also higher in lethal sepsis. Gamma interferon levels were significantly higher in lethal sepsis compared with ischemia-reperfusion (p = 0.005). Studies over time showed that CD11b expression and interferon gamma were both more marked at 6 hr than at 24 hr in lethal sepsis. This pattern was not observed in sublethal sepsis or in ischemia-reperfusion. CD11b/c expression on the other hand remained elevated at comparable levels at 6 and 24 hr in lethal sepsis. B-cell I-A expression in ischemia-reperfusion and sublethal sepsis decreased at 24 hr compared with baseline. Lethal sepsis in rats injected with enterotoxin producing staphylococcus results in phasic alterations in neutrophil CD11b and plasma interferon levels prior to death. In analogy to the findings of monocyte decreases in DR expression observed in human trauma and sepsis, rat B-cell I-A expression showed decreases in sublethal sepsis as well as in ischemia-reperfusion injury. However, this was not observed in lethal sepsis. These findings have implications in understanding the immunologic/inflammatory changes observed in human sepsis and trauma.