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  • Author or Editor: M. Raju x
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Abstract  

A series of silicon containing poly(ester imide)s [PEIs] were synthesized using novel vinyl silane diester anhydride (VSEA) and various aromatic and aliphatic dimines by two-step process includes ring-opening polyaddition reaction to form poly(amic acid) and thermal cyclo-dehydration process to obtain poly(ester imide)s. VSEA was synthesized by using dichloro methylvinylsilane and trimellitic anhydride in the presence of K2CO3 by nucleophilic substitution reaction. The PEIs were characterized by FTIR spectroscopy. The thermal properties of PEIs were investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) methods. The prepared PEIs showed glass transition temperatures in the range of 320–350°C and their 5% mass loss was recorded in the temperature range of 500–520°C in nitrogen atmosphere. These had char yield in the range of 45–55% at 800°C.

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Field experiments were conducted at the Agricultural College and Research Institute, Tamil Nadu Agricultural University, Killikulam, India during the kharif (July to November) and summer (December to April) seasons of 1999 and 2000 in a randomized block design. The treatment consisted of three pre-emergence herbicides (pretilachlor + safener 0.3 kg ha-1 4 days after sowing [DAS], butachlor 1.0 kg ha-1 8 DAS and pendimethalin 1.0 kg ha-1 8 DAS) and one early post-emergence herbicide (butanil 3.0 ha-1 15 DAS), each in combination with mechanical or hand weeding 30 and 45 DAS. In addition, green manure (Daincha) intercropping and incorporation, mechanical and hand weeding twice alone (25 and 50 DAS) were compared with the unweeded check. The results revealed that the pre-emergence application of pretilachlor + safener 0.3 kg ha-1 + hand weeding twice (30 and 45 DAS) promoted higher yield attributes and maximum yield in wet-seeded rice.

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A field experiment was conducted at the Main Research Station, University of Agricultural Sciences, Dharwad, India, on medium black soils during the kharif (wet) season of 1999. The experiment was laid out in a randomized complete block design with varying N/P ratios (0.67 to 2.00) along with a control with a constant level of potassium (60 kg ha-1). The results revealed that the number of green leaves plant-1, the dry matter accumulation in the leaves, leaf area (dm2 plant-1) and leaf area index (LAI) increased up to the flowering stage (65 DAS) and thereafter declined. In the early stages (seedling and button stages) there was no significant variation with respect to the number of green leaves plant-1 among the treatments except in the control. Similarly, leaf area and LAI did not vary at the seedling stage. Treatments receiving N/P ratios of ?1.0 or 1.0 with higher doses of nitrogen (120 kg N ha-1) gave a significantly higher number of green leaves plant-1, leaf area and LAI as compared to N/P ratios of <1.0 and the control in later stages. The dry matter accumulation in the leaves (g plant-1) differed in all the stages, but higher values were recorded in these same treatments. Thus, due to the higher number of green leaves, higher LAI and greater dry matter accumulation in the leaves, the treatments with an N/P ratio of ?1.0 or 1.0 with 120 kg N ha-1 produced higher seed yields (3188 to 3554 kg ha-1) than other N/P ratios (2761 to 3009 kg ha-1). The highest yield (3554 kg ha-1) was recorded with an N/P ratio of 1.0 in the treatment receiving 120 kg N and 120 kg P2O5 ha-1. The correlation coefficients between these photosynthetic attributes and seed yield were also positive and significant.

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Abstract

Thermal decomposition kinetics of calix[6]arene (C6) and calix[8]arene (C8) were studied by Thermogravimetry analysis (TG) and Differential thermal analysis (DTA). TG was done under static air atmosphere with dynamic heating rates of 1.0, 2.5, 5.0, and 10.0 K min−1. Model-free methods such as Friedman and Ozawa–Flynn–Wall were used to evaluate the kinetic parameters such as activation energy (E a) and pre-exponential factors (ln A). Model-fitting method such as linear regression was used for the evaluation of optimum kinetic triplets. The kinetic parameters obtained are comparable with both the model-free and model-fitting methods. Within the tested models, the thermal decomposition of C6 and C8 are best described by a three dimensional Jander's type diffusion. The antioxidant efficiency of C6 and C8 was tested for the decomposition of polypropylene (PP).

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Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Kumar Raju, P. Sugathan, T. Seshi Reddy, B. Thirumala Rao, S. Muralithar, R. Singh, R. Bhowmik and P. Madhusudhana Rao

Abstract  

The high spin level structure of 73As nucleus is studied by populating the nucleus in 64Ni(12C,p2n)73As reaction. Level scheme is revised significantly. Positive parity sequence is extended up to 33/2+ and a negative parity side band is identified and extended up to high spins 37/2. In addition about 15 new energy levels and a total of about 25 new gamma transitions were placed in the level scheme.

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