Range and energy-loss of 16.34 Mev/u 238U in kapton polyamide

Abstract

The range and energy-loss of 16.34 MeV/u ²³⁸U in Kapton-polyamide plastic have been measured by the nuclear track technique. The experimental ranges are compared with two sets of theoretical values. It has been observed that ranges obtained from the computer code ‘DEDXT’ are found to be 5–8% lower as compared to measured ones whereas those from Northcliffe and Schilling are about 10–15% overestimated above 8 MeV/u.     

Proton induced modification in Poly(ethylene terephthalate)

A systematic investigation of 62 r MeV proton irradiated Poly(ethylene terephthalate) (PET) has been carried out using Fourier Transformed Infrared Spectroscopy, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction spectroscopy. The experiments revealed a restoration of the crystalline matrix and simultaneous decrease in thermal stability in the irradiated polymer as a function of dose, indicating that PET underwent both degradation and cross-linking by proton irradiation.     

A study of the activation energy of thermal decomposition of irradiated polymers

The ion irradiation of polymeric solids induces numerous modifications in the polymer properties thus increasing their applicability in various fields. The present work looks into the aspect of thermal modifications induced in the irradiated polymers. The kinetics of thermal decomposition of polymers is investigated by using the thermogravimetric (TG) technique. It has been observed that the degradation of polymers is a multi-step process that involves sequential and competing processes, and obeys the Arrhenius kinetics which allows us to connect the rate constant with the absolute temperature and the activation energy. The activation energy of thermal decomposition has been calculated from the TG curves, and its variation with different irradiation doses has been derived.     

Electron induced modification in poly(ethylene terephthalate)

Abstract

The effect of 100 kGy dose of 2 MeV electron irradiation on Poly(ethylene terepthalate) (PET) has been studied by different characterisation techniques such as the Fourier transformed IR spectroscopy, electron spin resonance spectroscopy, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction analysis. Oxidative degradation leading to amorphisation of the polymer has been observed from spectral analysis. The thermal stability of the polymer was found to decrease due to electron irradiation. The thermal decomposition temperature as well as the melting temperature in case of irradiated PET was found to be decreased due to electron bombardment. A decrease in crystallinity of the polymer has also been observed after irradiation.     

A Generalization of Commutativity Degree of Finite Groups

The commutativity degree of a finite group is the probability that two arbitrarily chosen group elements commute. This notion has been generalized in a number of ways. The object of this article is to study yet another generalization of the same notion, which further extends some of the existing generalizations.     

Electronic Absorption Spectra of 2-Fluoro-4-bromo, 4-Fluoro-2-bromo and 2-Fluoro-5-bromo Toluenes

Abstract

Absorption spectra of 2-Fluoro-4-Bromo, 4-Fluoro-2-Bromo and 2-Fluoro-5-Bromo Toluenes have been investigated in the near ultraviolet region in vapour phase. The band systems correspond to allowed transitions with the most intense bands at 2742.09 Å (36458 cm^?1), 2745.96 Å (36406 cm^?1) and 2771.74 Å (36068 cm^?1) identified as 0,0 transitions in 2-Fluoro-4-Bromo, 4-Fluoro-2-Bromo and 2-Fluoro-5-Bromo Toluenes respectively. The bands in 4-Fluoro-2-Bromo Toluene have been analysed in terms of the ground state fundamental 208 cm^?1 and excited state fundamentals 244, 611, 855 and 1211 cm^?1 and the bands in 2-Fluoro-4-Bromo and 2-Fluoro-5-Bromo Toluenes are explained in terms of the upper state fundamentals 716, 987 and 1230 cm^?1 and 722, 886 and 2130 cm^?1 respectively.     

The Electronic and Infrared Absorption Spectra of Toluene-d

Abstract

The infrared and ultraviolet absorption spectra of toluene-d have been investigated for the first time in the regions 400 - 4000 cm^?1 and 2350 ?2750 A° respectively. The intense band at 2666.3 A°(37494 cm^?1) in the u.v. vapour absorption spectrum has been identified as the o,o band and others have been interpreted in terms of the three (519,632 and 785 cm^?1) ground state and the six (454,526,743,935,963 and 1180 cm^?1 excited state fundamentals. The correlation of the various frequencies of the ground and excited states of toluene and toluene-d has been done. The observed isotopic shift for toluene-d is 14 cm^?1.     

A convenient one-pot synthesis of N-fused 1,2,4-triazoles via oxidative cyclization using chromium (VI) oxide

A facile one-pot synthesis of N-fused 1,2,4-triazoles from heterocyclic hydrazines and aldehydes is reported. The reaction is efficiently promoted by chromium (VI) oxide to afford the desired products mostly in high yields and in relatively short time. The high yield of the products and short reaction time are notable advantages of the developed protocol. This protocol is effective toward various substrates having different functionalities.     

A convenient one-pot synthesis of 3,5-diarylisoxazoles via oxidative cyclisation using catalytic CuBr2 and oxone

A facile one-pot synthesis of 3,5-diarylisoxazoles from α,β-unsaturated ketones and hydroxylamine hydrochloride is reported. The reaction is efficiently promoted by catalytic CuBr₂ and Oxone to afford the desired products mostly in high yields and in relatively short time. The mild nature of the synthesis and short reaction time are notable advantages of the developed protocol. This protocol is effective toward various substrates having different functionalities.