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- Author or Editor: P. Sharma x
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Abstract
Bulk samples of Se85-xTe15Bix glassy alloys are obtained by melt quenching technique. Differential scanning calorimetry has been applied to determine the thermal properties of Se-rich Se85-xTe15Bix glassy alloys at different heating rates. The glass transition temperature (T g) is found to shift to a higher temperature with increasing heating rate and with Bi addition. Activation energy and fragility of the system is also calculated. Specific heat is evaluated and a jump in heat capacity is observed at T g. Theoretical parameters viz; density, molar volume, number of atoms per unit volume, lone pair electrons and cohesive energy of the system are also reported.
Abstract
This paper compares the profiles of research output and transnational cooperation (as revealed through multicountry publications) of thirty six countries in ten subfields of Physics during the period 1981–1985. The data for comparative analysis were taken fromBraun et al. Since raw counts of publications are confounded by the size of the countries and the size of the research fields, this comparison is made, using relative indicators — activity index and collaboration index. The structures of research output and transnational cooperation are analyzed through Correspondence Analysis, which leads to the identification of countries with similar profiles (of research output and transnational cooperation) and the spatial representation of countries and Physics subfields. The configurations of research output and transnational cooperation are compared to assess the concordance between the policies of these countries for research and transnational cooperation in Physics.
Abstract
This paper seeks to compare the research priorities of thirty three countries in five macrofields (Physics, Chemistry, Biology, Mathematics and Engineering & Technology) in two time spans: 1980–1984 and 1985–1989. Comparative analysis is based on the distribution of publications in different fields. Since the raw counts of publications are confounded by the size of the countries and the size of the subject fields, a relative index — Research Priority Index (PI) — is computed for cross-national comparisons. Correspondence analysis is applied to the asymmetrical matrices of priority profiles to reveal the structure of multivariate relationships between countries and fields. The configurations for the two time-spans, obtained through correspondence analysis, are compared to reveal the dynamics of research priorities of these countries.
In the present study on the self-incompatibility in inbred lines of ten local Indian cultivars (Pusa Chetki, Chetki Long, Aushi, Alipur Local White, Jaunpuri, Half Red, Scarlet Red, Chinese Pink, Desi Red and Khasi Kata) of radish ( Raphanus sativus L.), Pusa Chetki, Chetki Long, Aushi, Alipur Local White and Jaunpuri were classed as selfcompatible, Half Red, Scarlet Red and Chinese Pink as intermediate and Desi Red and Khasi Kata as self-incompatible. The highest number of germinated pollen grains and pollen tubes was observed in Pusa Chetki, followed by Alipur Local White, Jaunpuri, Aushi and Chetki Long. The discrepancy in the number of germinated pollen grains in the stigmas may be explained by the inhibitory action of large numbers of self-incompatible pollen grains on the stigma. When two lines, Desi Red and Khasi Kata, were grown under different temperature and photoperiod conditions, no breakdown in self-incompatibility was observed, and the flowering periods of these lines are naturally well synchronized. It is well known that uniform and effective cross-pollination may be of great importance for obtaining a high quantity of hybrid seed in self-incompatible types. To produce single cross hybrid seed, the inbred lines Desi Red and Khasi Kata can be used as parental lines.
The results of a field study revealed that the application of fertilizers to the companion crop in a millet/legume intercropping system is essential to optimize the yield of the legume component. Supplying nutrients to the main crop alone tended to decrease the productivity of the companion crop, probably because of shading as a result of overgrowth of the main crop. The highest contents of N and P in the grain and straw of the intercrop were recorded with 100% of the recommended dose to both the component crops (M100I100). However, the uptake of nutrients was highest from the plots receiving 50 and 100% of the recommended dose to the main and companion crop, respectively (M50I100). Higher uptake was due to the fact that the yields increased to a greater extent than the nutrient concentrations.
A greenhouse experiment was conducted to study the impact of premethanation (PREME) and postmethanation (POME) distillery effluent applied as pre-sowing irrigation (PSI) along with graded levels of inorganic fertilizers on the grain and straw yield and nutrient content of a rice crop (var. PR 116). Maximum grain yield (29.4 g pot −1 ) was recorded with the application of 100% recommended NPK along with one pre-sowing irrigation (PSI) through POME and the lowest yield (7.4 g pot −1 ) was obtained with 2 PSI applied through PREME without any inorganic fertilizers. The application of POME equivalent to 1 PSI was more effective in increasing the grain and straw yield of rice than no POME application or POME application equivalent to 2 PSI. A significant decrease in yield occurred with the application of 2 PSI of either effluent, and beyond 2 PSI the rice seedlings did not grow.In comparison to POME, the application of PREME increased the content of K (5%), Cu (10%), Fe (17%) and Mo (21%), but decreased that of P (12%), S (5%) and Mg (11%) in rice grain. In rice straw an increase was only observed in K (9%) and Mo (14%), while the contents of other nutrients (P, S, Zn, Cu, Mn) decreased by 8 to 21%. An increase in the level of effluent from 0 to 2 PSI significantly increased the content of N (by 21%), K (11%), S (10%), Zn (9%), Cu (21%) and Mo (8%), but decreased that of P (16%) and Mg (19%) in rice grain. In the case of rice straw, an increase in K (28%), S (32%), Cu (65%) and Mo (45%) content was recorded. Effluent application, inorganic fertilizers and their interactions had a significant effect on both the grain and straw yields and on the nutrient concentration in the plants.
Abstract
The curing behaviour of diglycidyl ether of bisphenol-A (DGEBA) was investigated by the dynamic differential scanning calorimetry using varying molar ratios of aromatic imide-amines and 4,4′-diaminodiphenylsulfone (DDS). The imide-amines were prepared by reacting 1 mole of naphthalene 1,4,5,8-tetracarboxylic dianhydride (N) and 4,4′-oxodiphthalic anhydride (O) with 2.5 moles of 4,4′-diaminodiphenyl ether (E) or 4,4′-diaminodiphenyl methane (M) or 4,4′-diaminodiphenylsulfone (S) and designated as NE/OE or NM/OM or NS/OS. The mixture of the imide-amines and DDS at ratio of 0:1, 0.25:0.75, 0.5:0.5, 0.75:0.25 and 1:0 were used to investigate the curing behaviour of DGEBA. A single exotherm was observed on curing with mixture of imide-amines and DDS. This clearly shows that the two amines act as co-curing agents. Curing temperatures were higher with imide-amines having sulfone linkage irrespective of anhydride. Curing of DGEBA with mixture of imide-amines and or DDS resulted in a decrease in characteristic curing temperatures. The thermal stability of the isothermally cured resins was also evaluated using dynamic thermogravimetry in a nitrogen atmosphere. The char yield was higher in case of resins cured imide-amines based on N and E. The activation energy of decomposition and integral procedural decomposition temperature were also calculated from the TG data.
Curing kinetics and thermal stability of diglycidyl ether of bisphenol
Mixture of aromatic imide-amines of benzophenone 3,3′, 4,4′-tetra-carboxylic acid dianhydride and 4,4′-diaminodiphenylsulfone
Abstract
Curing kinetics of diglycidyl ether of bisphenol-A (DGEBA) in the presence of varying molar ratios of aromatic imide-amines and 4,4′-diaminodiphenylsulfone (DDS) were investigated by the dynamic differential scanning calorimetry. The imide-amines were prepared by reacting 1 mole of benzophenone 3,3′,4,4′-tetracarboxylic acid dianhydride (B) with 2.5 moles of 4,4′-diaminodiphenyl ether (E)/ or 4,4′-diaminodiphenyl methane (M)/ or 4,4′-diaminodiphenylsulfone (S) and designated as BE/ or BM/ or BS. The mixture of imide-amines and DDS at ratio of 0:1, 0.25:0.75, 0.5:0.5, 0.75:0.25 and 1:0 were used to investigate the curing behaviour of DGEBA. The multiple heating rate method (5, 10, 15 and 20°C min−1) was used to study the curing kinetics of epoxy resins. The peak exotherm temperature was found to be dependent on the heating rate, structure of imide-amines as well as on the ratio of imide-amine: DDS used. A broad exotherm was observed in the temperature range of 180–230°C on curing with mixture of imide-amines and DDS. Curing of DGEBA with mixture of imide-amines and/or DDS resulted in a decrease in characteristic curing temperatures. Activation energy of curing reaction as determined in accordance to the Ozawa’s method was found to be dependent on the structure of amine. The thermal stability of the isothermally cured resins was also evaluated using dynamic thermogravimetry in a nitrogen atmosphere. The char yield was highest in case of resins cured using mixture of DDS: BS (0.25:0.75; EBS-3), DDS: BM (0.5: 0.5; EBM-2) and DDS: BE (0.5: 0.5; EBE-2).
The present investigation was undertaken to optimize the level of ingredients (milk fat, sugar, and mango pulp) for functional dairy beverage using Response Surface Methodology. Central Composite Rotatable Design with milk fat (%), sugar (%), and mango pulp (var. Chaunsa, %) as independent variables produced 20 different combinations that were used to investigate the effect on viscosity (cP), antioxidant activity, and overall acceptability. The response surface three dimensional graphs were plotted as a function of two variables to show the effect of level of ingredients on physico-chemical and sensory properties of the beverage. Significant correlation models were established with the coefficient of correlation (R2) greater than 0.8. An optimization of process variables was attempted for maximum antioxidant activity and overall acceptability. ANOVA tables revealed that increase in fat and sugar levels lowered the antioxidant activity, while enhancement of mango pulp significantly increased both antioxidant activity and overall acceptability of the beverage. The optimized levels of ingredients were 0.5% milk fat, 6.0% sugar and 30% mango pulp.
Summary
A simple, rapid, and precise reversed-phase high-performance liquid chromatographic method for simultaneous analysis of metformin hydrochloride, pioglitazone hydrochloride, and glibenclamide in a tablet dosage form has been developed and validated. Chromatography was performed on a 25 cm × 4.6 mm i.d., 5-μm particle, C18 column with 55:45 (v/v) acetonitrile — potassium dihydrogen phosphate buffer (pH adjusted to 3.0 ± 0.1 with 5% orthophosphoric acid) as mobile phase at a flow rate of 1.5 mL min−1. UV detection was performed at 230 nm. Total run time was 10 min; metformin hydrochloride, pioglitazone hydrochloride, and glibenclamide were eluted with retention times of 1.362, 3.418, and 7.395 min, respectively. The method was validated for accuracy, precision, linearity, specificity, and sensitivity in accordance with ICH guidelines. Validation revealed the method is specific, rapid, accurate, precise, reliable, and reproducible. Calibration plots were linear over the concentration ranges 200–1000 μg mL−1 for metformin hydrochloride, 200–1000 μg mL−1 for pioglitazone hydrochloride, and 50–300 μg mL−1 for glibenclamide. Limits of detection were 6.3, 15.4, and 8.2 ng mL−1 and limits of quantification were 19.09, 46.66, and 24.84 ng mL−1 for metformin hydrochloride, pioglitazone hydrochloride, and glibenclamide, respectively. The high recovery and low coefficients of variation confirm the suitability of the method for simultaneous analysis of the three drugs in tablets. The validated method was successfully used for quantitative analysis of triglycomate tablets.
