Optimization of a conducting cooling fin with a heat sink using optimality criterion

An optimality criterion is used to obtain a minimum volume design of a conducting fin with an arbitrarily located heat sink whose volume is a design variable. The finite element method is used for the analysis. The effect of the heat sink as an active cooling device on the optimum volume of the fin is studied     

On vibration of plates with varying stiffener length

Fabrication considerations sometimes make it necessary to stop a stiffening member at a short distance away from the supporting edge of a panel. The effect of this gap between the stiffener tip and the supporting edge on the natural frequencies is investigated here by using a finite element approach.     

The mass spectrum of 2,4-dihydroxybenzophenone oxime

2,4-Dihydroxybenzophenone Oxime is found to undergo loss of OH·, H₂O, NHOH·; and PhCNO when subjected to electron impact, revealing novel hydrogen and skeletal migrations. The fragmentation mechanisms are found to differ considerably from those of benzophenone oxime and we confirmed these cleavages by exact mass measurements and deuterium labelling.     

Direction of enolization of 1:3-diketones by mass spectrometry

A novel method of establishing the direction of enolization of a 1:3-diketone is to examine of the mass spectrum of the isoxazole obtained from it by hydroxylamine treatment. Thus, the products obtained from five 1:3 diketones,viz. l-(2-naphthyl)-3-phenylpropane-l :3-dione and its 3-p-toluyl,p-methoxyphenyl,p-nitrophenyl andp-chlorophenyl analogues, consist of both the possible isomeric 3:5-disubstituted isoxazoles in each case, indicating that each diketone exists in both the enolic forms. The percentage of the enols was derived, in a qualitative manner, from the ratio between the percentage abundances of the aroyl and naphthoyl cation peaks present in the mass spectrum of the product from each diketone. In four out of the five cases, each possible isomeric isoxazole was synthesised by the unambiguous chalconedibromide method and examination of the mass spectrum in each case revealed that either the aroyl or the naphthoyl cation peak was exhibited depending on whether the 5-substituent was an aryl or a naphthyl group respectively. A re-examination of the direction of enolization of 4-methoxydibenzoylmethane revealed that it existed in both the enolic forms, contrary to earlier observations.     

Magnetic behavior of amorphous Fe−Ni−Zr alloys and their response to radiation damage

The magnetic properties of two amorphous Fe?Ni?Zr alloys, Fe_89.7Ni_0.03Zr₁₀ and Fe₇₀Ni₂₀Zr₁₀, both in the “as cast” and neutron irradiated states were investigated by Mössbauer spectroscopy and dc magnetic susceptibility measurements. The upper magnetic ordering temperatures of Fe_89.7Ni_0.03Zr₁₀ are 232K and 246K for the “as cast” and irradiated samples, respectively. The magnetic ordering temperature for Fe₇₀Ni₂₀Zr₁₀ was about 478K for both the “as cast” and irradiated samples. Both compositions yield magnetic hyperfine spectra, which show a considerable relaxation effect that must be explicitly considered in the calculation of the average local Fe moments. When this is done, these values derived from Mössbauer spectra are in good agreement with the dc susceptibility values. The effects of neutron irradiation on the magnetic properties of these alloys are small.     

Monte-Carlo study of spin-glass behaviour in concentrated binary magnetic systems

Monte Carlo calculations on a stochastic Ising model of a concentrated binary magnetic system with very strong, quenched bond disorder were done on square lattices. The specific heat and static susceptibility show rounded peaks at a temperature below which field-cooling effects and long time relaxation, typical of spin-glasses, start appearing.