Combustion synthesis of oxide materials for nuclear waste immobilization

Oxide materials like perovskite, zirconolite, hollandite, pyrochlore, NASICON and sphene which are used for nuclear waste immobilization have been prepared by a solution combustion process. The process involves the combustion of stoichiometric amount of corresponding metal nitrates and carbohydrazide/tetraformyl trisazine/diformyl hydrazide at 450°C. The combustion products have been characterized using powder X-ray diffraction, infrared spectroscopy, and²⁹Si MAS-NMR. The fine particle nature of the combustion derived powders has been studied using density, particle size, BET surface area measurements and scanning electron microscopy. Sintering of combustion derived powder yields 85–95% dense ceramics in the temperature range 1000°–1300°C.     

A study of PFBR auxiliary neutron source strength activation and its variability with respect to the neutron spectrum and ~(123)Sb capture cross section

In fast reactors, the inherent neutron source strength is often insufficient for monitoring the reactor start-up operation with ex-core detectors. To increase the subcritical neutron flux, an auxiliary neutron source subassembly(SSA) is generally used to overcome this problem. In this study, the estimated neutron source strength and detector count rate of an antimony-beryllium-based SSA are obtained using the deterministic transport code DORT and Monte Carlo calculations. Because the antimony activation rate is a critical parameter, its sensitivity to the capture cross section and neutron flux spectrum is studied. The reaction cross section sensitivity is studied by considering data from different evaluated nuclear data files.It is observed that, because of the variation in the cross sections from different evaluated nuclear data files, the values of the saturation gamma( 1.67 MeV) activity and neutron strength predicted by ORIGEN2 lie within ±2%.The obtained antimony activation rate and sensitivity to the neutron flux are partially validated by irradiating samples of antimony in the KAMINI reactor. The average onegroup capture cross sections of bare and cadmium-covered ~(123)Sb samples obtained by the ratio method are 4.0 and 1.78 b, respectively. The results of the calculation predicting the activated neutron source strength as a function of operating time and sensitivity to the neutron spectrum in the irradiation region are also presented.     

Fasting and postprandial lipid response to the consumption of modified milk fats by guinea pigs

The objective of the present study was to investigate the effect of three modified milk fats with different melting profiles on fasting and postprandial lipid responses and on fecal fat content in guinea pigs. We hypothesized that the consumption of modified milk fat with a high m.p. results in reduced fasting and postprandial lipid responses compared with that of modified milk fat fractions with lower m.p. To test this hypothesis, male Hartley guinea pigs were fed isoenergetic diets containing 110 g of fat/kg, either from one of the three modified milk fats with high (HMF), medium (MMF), or low melting profiles (LMF), or from one of the two reference fats as whole mil fat (MF) or a fat blend similar to that of nonhydrogenated soft margarine (MA) for 28 d. Food intake (P<0.05) and body weight gain (P<0.05) were reduced in the animals fed the HMF diet compared with the other groups. In the fasting state, plasma LDL cholesterol was highest in animals fed the LMF diet, intermediary in those fed the MMF and MF diets, and lowest in those fed the HMF and MA diets (P<0.05). Postprandially, the areas under the 0- to 3-h curves for the changes in plasma TG were lower in the HMF group than in the MA- and LMF-fed guinea pigs (P<0.05). The fecal fat content was higher (P<0.05) in the HMF group compared to the other milk fat groups. The present results suggest that modified milk fats can impact food intake, body weight gain, fasting cholesterolemia, and postprandial triglyceridemia, and these changes may be attributed to an altered fat absorption.     

Novel polyvinyl alcohol polymer based nanostructure with ferrites co‐doped with nickel and cobalt ions for magneto‐sensor application

Uniform nanosheet‐like structures were synthesized by the polymer based co‐precipitation route. Different concentrations of polyvinyl alcohol (pure (0 g), 0.2 g and 0.5 g) were added to nickel (Ni) and cobalt (Co) ion co‐doped ferrite magnetic nanoparticles. X‐ray diffraction confirmed a spinel structure phase of the Ni ? Co ferrites. Enhanced average crystallite size (6.7%) of the Ni ? Co ferrites was found on polymer incorporation. The molecular functional group of polyvinyl alcohol and Ni ? Co ferrites was confirmed by infrared and Raman spectroscopy techniques. On adding polymer, the spherical morphology of the Ni ? Co ferrites was tailored to nanosheets (200 nm × 300 nm). Therefore, the polymer based co‐precipitation technique is an inexpensive, simple and effective route to engineer the morphology of the magnetic nanostructure and could be useful for gas sensor and magnetic sensors. © 2016 Society of Chemical Industry     

Low Velocity Impact and Mechanical Behaviour of Shot Blasted SiC Wire-Mesh and Silane-Treated Aloevera/Hemp/Flax-Reinforced SiC Whisker Modified Epoxy Resin Composites

Silicon - In this research the effect of adding silicon carbide nano whiskers (SiCw) into epoxy resin and the impact of reinforcing surface treated SiC wire-mesh (SiCwm) and woven...     

Ca3(PO4)2‐incorporated poly(ethylene oxide)‐based nanocomposite electrolytes for lithium batteries. Part II. Interfacial properties investigated by XPS and a.c. impedance studies

The surface layer and elemental composition of a lithium‐metal electrode before and after in contact with nanocomposite polymer electrolytes (NCPEs) comprising poly(ethylene oxide)/Ca₃(PO₄)₂/LiX (X = N(CF₃SO₂)₂, ClO₄) were analyzed by X‐ray photoelectron spectroscopy. The presence of Li₂CO₃/LiOH in the outer layer of the native film was identified. The formation of LiF was detected on lithium surface when in contact with NCPE containing LiN(CF₃SO₂)₂ and is attributed to the reaction between the native film and impurities. Li/NCPE/Li symmetric cells were assembled, and the thickness of the solid electrolyte interface as a function of time was analyzed at 60°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Six Sigma for Software Application of Hypothesis Tests to Software Data

The article discusses statistical analysis on Release data from a mature Global Software Group (GSG) with three business domains with an aim to ascertain if any correlation can be established between the data collected after release and the benefits to the centre from the outcome of the analysis. Thus re-evaluating the process involved in creating and delivering software products to our customers. This article will strive to explain some of the Six Sigma methodologies and tools used in comparing groups (ANOVA method) and categorical data analysis techniques on software data. The paper will also discuss in detail normal distribution, tests for normality and comparative methods along with Contingency Table Analysis (Mosaic plots) and Correspondence Analysis. The application of statistics for SOFTWARE process improvement is increasing in the industry; we present how these techniques can be applied in practice.     

Factor oriented requirement coverage based system test case prioritization of new and regression test cases

Test case prioritization involves scheduling test cases in an order that increases the effectiveness in achieving some performance goals. One of the most important performance goals is the rate of fault detection. Test cases should run in an order that increases the possibility of fault detection and also that detects the most severe faults at the earliest in its testing life cycle. In this paper, we propose to put forth a model for system level test case prioritization (TCP) from software requirement specification to improve user satisfaction with quality software that can also be cost effective and to improve the rate of severe fault detection. The proposed model prioritizes the system test cases based on the six factors: customer priority, changes in requirement, implementation complexity, completeness, traceability and fault impact. The proposed prioritization technique is validated with two different validation techniques and is experimented in three phases with student projects and two sets of industrial projects and the results show convincingly that the proposed prioritization technique improves the rate of severe fault detection.