Characterization and photoluminescence studies on hydrothermally synthesized Mn-doped barium titanate nano powders

Manganese doped cubic barium titanate nanocrystals with [Mn/Ti] mole percent varying from 0.1 to 3 were prepared through hydrothermal route at 150 °C. The mean crystallite diameters obtained for different Mn concentrations varied within 26 to 30 nm. TEM of a typical sample showed most of the particles as single crystallites (particle size 15-40 nm) with some weakly agglomerated particles. The photo luminescent (PL) spectra of each sample showed a sharp peak in the blue band centered approximately at 464 nm and a weaker peak in the green band centered nearly at 494 nm. The luminescent efficiency passed through maxima for the sample with 2% [Mn/Ti] molar ratio. Effect of calcination temperature in the range of 200 to 600 °C on PL spectra showed that the intensity of peak corresponding to blue region decreased with the increase in calcination temperature from 200 to 600 °C and for the sample calcined at 600 °C, only a broad peak corresponding to green luminescence region was observed.     

Coverage Modeling and Reliability Analysis Using Multi-state Function

Fault tree analysis is an effective method for predicting the reliability of a system.It gives a pictorial representation and logical framework for analyzing the reliability.Also,it has been used for a long time as an effective method for the quantitative and qualitative analysis of the failure modes of critical systems.In this paper,we propose a new general coverage model (GCM) based on hardware independent faults.Using this model,an effective software tool can be constructed to detect,locate and recover fault from the faulty system.This model can be applied to identify the key component that can cause the failure of the system using failure mode effect analysis (FMEA).     

A neuro-fuzzy approach for prediction of longitudinal wave velocity

Adaptive neuro-fuzzy inference system (ANFIS) is rapidly gaining popularity in the area of geophysics and geomechanics. This paper discusses the importance of ANFIS to prediction of p-wave velocity and its advantages over other conventional methods of computing. This paper deals with the application of a ANFIS to predict longitudinal wave velocity. P-wave measurement, which is also an indicator of peak particle velocity during blasting in a mine, is an important parameter to be determined to minimize the damage caused by ground vibrations. A number of previous researchers have tried to use different empirical methods to predict p-wave. But these empirical methods have their limitations due to its less versatile application. The fracture propagation is not only influenced by the physico-mechanical parameters of rock but also on the dynamic wave velocity of rock (e.g., compressional wave velocity). It has wide application in the different field of geophysics. An ANFIS model is designed to predict the compressional wave velocity of different rocks. The fracture roughness coefficient and physico-mechanical properties are taken as input parameters and compressional wave velocity as output parameters. The error for the predicted values is found to be negligible (0.5%) and generalization capability of the neuro-fuzzy model is found to be very useful for such type of geophysical problems.     

Reconnaissance mapping and management of salt-affected soils using satellite images

The Indo-Gangetic alluvial plain is subjected to large scale soil alkalization. In order to map and characterize salt-affected soils, with the aim of applying management techniques, Etah district in Uttar Pradesh, located between 26o^o45' to 28^o02' N and 78^o15' to 79^o20' E was selected. Multidate, high resolution, IRS-LISS II, geocoded FCC images on 1550 000 scale were used. Integrating visual image interpretation, physiographic analysis, ground data and laboratory analysis of soil samples, a legend for mapping salt-affected soils (SAS) was formulated. Based on variations in physicochemical properties: nature, intensity and depth wise distribution of salts, five categories of SAS requiring specific reclamation measures were identified. Soil categories S2, S3 and S4 have a gypsum requirement (GR) of 20, 12 and 4t/ha^-1 respectively. Reclamation of medium to heavy textured highly alkali soils requires the addition of amendments and a rice-wheat rotation for the initial 3-4 years. Under resource constraints, pit planting of Prosopis juliflora can bring about slow but effective reclamation. The soil category S5 is slightly alkali in the substratum, needing only biological reclamation by growing salt tolerant varieties of rice and wheat crops. Soils of category S1 are saline and need management by hydrological treatments. Incorporation of village boundaries on a map showing SAS would facilitate decision taking in planning reclamation projects and accelarate management operations directly at village level.     

Biophysicochemical evaluation and micropropagation study of Jatropha curcas L. collections for biodiesel production

Jatropha curcas, a member of the Euphorbiaceae family, is an upcoming energy source, which promises to mitigate the energy crisis and environmental pollution. Jatropha curcas oil is looked up in terms of availability and cost and also has several applications and enormous economic benefits. The seed oils of five Jatropha curcas biotypes were screened and evaluated for their physiochemical parameters, viz. oil content (20–43%), biodiesel yield (48–66%), density (.866–.969 g/cm³), viscosity (50.12–93.79 mm³/s), iodine value (232.738–457.16 mg/g), free fatty acid (18.847–7.614 mg/g), saponification value (59.29–93.79 mg/g), flash point (125–220°C), fire point (155–260°C) and ash content (.19–.399%), which were estimated for selection of the elite Jatropha curcas biotype. The best shoot regeneration (60%) was observed in Murashige and Skoog (MS) medium supplemented with naphthalene acetic acid (0.5 ppm) and benzyl amino purine (2.0 ppm). Root induction (90%) was successfully obtained in plain MS. Acclimatisation and hardening was quite successful with survival rate of 70%.     

Quality,functionality, and shelf life of fermented meat and meat products: A review

Fermentation of meat is a traditional preservation method used widely for improving quality and shelf life of fermented meat products. Fermentation of meat causes a number of physical, biochemical, and microbial changes, which eventually impart functional properties, sensory characteristics, and nutritional aspects to these products and inhibit the growth of various pathogenic and spoilage microorganisms. These changes include acidification (carbohydrate catabolism), solubilization and gelation of myofibrillar and sarcoplasmic proteins of muscle, degradation of proteins and lipids, reduction of nitrate into nitrite, formation of nitrosomyoglobin, and dehydration. Dry-fermented sausages are increasingly being used as carrier of probiotics. The production of biogenic amines during fermentation can be controlled by selecting proper starter cultures and other preventive measures such as quality of raw materials, hygienic measures, temperature, etc.     

Oxidation of Cr(III) in tannery sludge to Cr(VI): field observations and theoretical assessment

Sludge, soil and leachate samples collected from a chromium-contaminated tannery waste dumping site in Kanpur, India, were found to contain considerable amounts of Cr(VI), despite the fresh tannery sludge containing little or no Cr(VI). Literature reports suggested that dry Cr(III) precipitates could be converted to Cr(VI) when heated in the presence of oxygen. Also, Cr(III) in aqueous phase could be oxidized through interaction with manganese dioxide (MnO2) surface to Cr(VI). Measurement of manganese in the sludge samples collected from the site showed concentrations up to 0.6 mg/g. Based on equilibrium calculations, it was determined that both dry phase Cr(III) oxidation by atmospheric oxygen and aqueous phase Cr(III) oxidation by MnO2 surface were thermodynamically feasible. It was further suggested that in aqueous phase, manganese may act effectively as an electron transporter between Cr(III) and dissolved oxygen during Cr(III) oxidation, leading to regeneration of MnO2 solid phase. Further, as dissolved Cr(III) is oxidized, dissolution of Cr(OH3) will take place to maintain the equilibrium between the dissolved and solid phases of Cr(III). In the pH range of 3-10, and at oxygen partial pressure (P(O2)) of 10(-6) atm or higher, equilibrium conditions stipulate nearly complete conversion of Cr(III) to Cr(VI). At P(O2) of 10(-20) atm or lower, very little Cr(VI) is expected to be present under equilibrium conditions. In the intermediate P(O2) regions, incomplete dissolution of the Cr(OH3) solid phase and only partial conversion of chromium from +3 to the +6 oxidation state is expected, especially at lower pH values.     

Comparative evaluation of extraction of tetra- and hexa-valent neptunium ions by CMPO in a room temperature ionic liquid

ABSTRACT

Solvent extraction studies were performed to understand the extraction behavior of Np⁴⁺ and NpO₂ ²⁺ from acidic feeds with CMPO (octyl (phenyl)-N,N-diisobutyl carbamoyl methyl phosphine oxide) dissolved in 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide, a water immiscible ionic liquid. Slope analyses on the distribution data revealed the extraction of ML₂ type species, where M = Np⁴⁺ or NpO₂ ²⁺, and L = CMPO. Studies were also carried out with Pu⁴⁺ and UO₂ ²⁺ under identical conditions. The nature of the extracted species was found to vary with the nature of the ionic species.     

Raman studies of structural rearrangements induced in human plasma lipoprotein carotenoids by malondialdehyde

Raman and resonance Raman spectra of plasma lipoproteins ± malondialdehyde were studied at concentrations which block the normal receptor-mediated uptake by cells. The strong resonance Raman bands at about 1010, 1162 and 1530 cm⁻¹, due to the presence of carotenoids in the lipoproteins, are envisaged as structural probes. High resolution resonance Raman spectra of the 1500–1600 cm⁻¹ region reveal multiple features suggesting the coexistence of several structural populations of β-carotene whose precise assignment is complex. When plasma lipoproteins are reacted with malondialdehyde, a complex change occurs in the resonance Raman banding of β-carotene in the 1500–1600 cm⁻¹ region. Malonaldehyde (MDA) also modifies the acoustical region (70–200 cm⁻¹ of low density lipoprotein (LDL) lipids. We suggest that malondialdehyde association with plasma lipoproteins alters the lipid structure via apoprotein or apoprotein/lipid associations.     

Optical and magnetic properties of Fe-doped CdS dilute magnetic semiconducting nanorods

Solvothermal technique has been used for the synthesis of Fe-doped CdS nanorods (Cd_1?xFe_xS) with (x = 0.0, 0.3, 0.5, 1.0, 1.5). Structural analysis carried out using X-ray diffraction reveals the formation of defect-free hexagonal phase of the CdS nanorods. Energy dispersive X-ray analysis confirms the presence of elements Cd, Fe and S in their stoichiometric ratio. Blue shift in the band gap, as compared to the bulk CdS, has been observed in UV–visible spectra. The decrease in the intensity of the photoluminescence peaks confirms the quenching of spectra upon Fe doping. Transmission electron microscopy, high-resolution transmission electron microscopy and selected area diffraction studies confirm the polycrystalline nature as well as growth of CdS nanorods along (112) plane. Magnetic study confirms the ferromagnetic nature of the synthesized nanorods. Magnetic saturation has been found to be 0.187, 0.300, 0.450, 0.675, 0.600 emu g^?1, respectively, for undoped, 3, 5, 10, and 15 % Fe-doped CdS.