A weightage formula to rerank periodicals in the field of microbiology

Ranking lists of periodicals in different scientific disciplines are generally based on the total number of citations derived from a group of source journals with equal weightage given to all citations irrespective of chronology. As a result, in all these ranking lists, the position occupied by the post-war journals, may not be an accurate index of their demand or usefulness to research workers in the concerned field. This may happen because the quantum of published literature in the new journals is limited by the period for which they have been in existence, which is in many cases less than 20 years. Moreover, many of the post-war journals appearing in all these recent ranking lists have started publication even after 1960s, and their enumerated citations cover in fact a variable period of less than 20 years unlike in the case of pre-war journals. To avoid such discriminating against new journals which necessarily have fewer citation credits Sengupta suggested earlier an off-setting weightage formula which has been applied in this paper to rerank microbiology periodicals. A revised ranking list in the field of microbiology has been recommended in preference to the earlier one compiled by Sengupta. Results and findings, after application of the weightage formula, have been presented and discussed in this paper.     

Optimisation of tensile membrane structures under uncertain wind loads using PCE and kriging based metamodels

Tensile membrane structures (TMS) are light-weight flexible structures that are designed to span long distances with structural efficiency. The stability of a TMS is jeopardised under heavy wind forces due to its inherent flexibility and inability to carry out-of-plane moment and shear. A stable TMS under uncertain wind loads (without any tearing failure) can only be achieved by a proper choice of the initial prestress. In this work, a double-loop reliability-based design optimisation (RBDO) of TMS under uncertain wind load is proposed. Using a sequential polynomial chaos expansion (PCE) and kriging based metamodel, this RBDO reduces the cost of inner-loop reliability analysis involving an intensive finite element solver. The proposed general approach is applied to the RBDO of two benchmark TMS and its computational efficiency is demonstrated through these case studies. The method developed here is suggested for RBDO of large and complex engineering systems requiring costly numerical solution.     

A widely linear temperature to frequency converter using athermistor in a pulse generator

A modification of an existing technique for thermistor linearization is presented. A temperature-measuring circuit using a thermistor in a specially designed pulse generator is used to obtain a highly linear relation between absolute temperature and frequency. The use of a general-purpose operational amplifier and two switching transistors in the design of the pulse generator provides a temperature scale that is linear over a wide range of values on a high degree of sensitivity. The result shows that an extremely high degree of linearity is achieved by this method     

Properties of YIG-based magnetic glass-ceramics with different nucleating agents

The effect of bismuth, silver oxide and palladium on the crystallization of yttrium iron garnet in Na₂O-SiO₂-Y₂O₃-Fe₂O₃ glass-ceramics has been investigated by X-ray diffraction thermal analysis, magnetic measurements and optical microscopy. It is found that the magnetic properties of these glass-ceramics can be altered significantly by a change in the nucleating agents and the heat treatment schedule. This behaviour is explained on the basis of the microstructure and the volume fraction of the different magnetic phases crystallized within the glasses.     

A higher-order triangular plate bending element revisited

A new formulation of an eighteen-degrees-of-freedom higher-order triangular plate bending element using triangular area co-ordinates is presented. The displacement function w is taken as the complete fifth-order polynomial in area co-ordinates. The normal slope along an edge of the triangle is constrained to vary cubically. The twenty-one constants are expressed explicity in terms of eighteen degrees of freedom. The element stiffness matrix is expressed as a product of component matrices for which explicit expressions are developed and presented. No numerical inversion or integration is necessary. The formulation is expected to be useful specially for microcomputers.     

Triglyceride composition of Buchanania lanzan seed oil

The fatty acid composition of Buchanania lanzan seed oil, determined by urea complex formation and gas liquid chromatography (g.l.c), was found to be: myristic, 0.6; palmitic, 33.4; stearic, 6.3; oleic, 53.7; and linoleic, 6.0%. Triglyceride compositions of the native seed oil and its randomised product were calculated from the fatty acid compositions of the triglycerides and of the corresponding 2-monoglycerides produced by pancreatic lipase hydrolysis. The oil is composed of 3.2, 35.8, 45.5 and 15.5% trisaturated, monounsaturated disaturated, diunsaturated monosaturated and triunsaturated glycerides respectively. The special characteristic of the B. lanzan seed oil is its content of 22.7, 31.0 and 11.3% dipalmitoolein, dioleopalmitin and triolein respectively. The percent GS₃ content in the oil increased from 3.2 to 7.5 by the process of randomisation. On directed interesterification the oil yielded a product with a slip point of 41.5°C which may be suitable as a coating material for delayed action tablets. The oil also appears to be a promising one as a commercial source of palmitic and oleic acids.     

A kinetic approach to the esterification of maleic anhydride with methanol on H-Y zeolite

The purpose of this work is to study the kinetics of the esterification of maleic anhydride with methanol to form dimethyl maleate in a batch reactor in the presence of H-Y zeolite as a catalyst. This is a series-parallel type multiple reaction where, the first reaction involves the formation of monomethyl maleate that further reacts with alcohol to form dimethyl maleate. Dimethyl maleate was found to be the only product in the reaction mixture. Temperature, speed of agitation, catalyst size, reactant mole ratio and catalyst loading have pronounced effect on the rate of the reaction. A homogeneous rate model and heterogeneous rate models have been derived and fitted with the experimental data. The activation energy was found to be 44.65 kJ/mol.     

Thermal performance optimization of a flat plate solar air heater using genetic algorithm

Thermal performance of solar air heater is low and different techniques are adopted to increase the performance of solar air heaters, such as: fins, artificial roughness etc. In this paper an attempt has been done to optimize the thermal performance of flat plate solar air heater by considering the different system and operating parameters to obtain maximum thermal performance. Thermal performance is obtained for different Reynolds number, emissivity of the plate, tilt angle and number of glass plates by using genetic algorithm.     

Magneto-thermo-visco-elastic waves in an initially stressed conducting layer

The aim of this paper is to investigate magneto-thermo-viscoelastic surface waves in electrically and thermally conducting layers involving time rates of strain and stress of ordern, the media being under an initial stress in the nature of hydrostatic tension or compression. The theory of magneto-thermo-visco-elastic surface waves in the conducting medium involving strain rate and stress rate ofnth order is derived under initial stress. This theory is then employed to obtain wave velocity equations in specific cases. Results obtained in the above cases reduce to well-known classical results when additional fields are absent.