An evaporated multilayer thin film RC notch filter

The fabrication and characteristics of multilayer film C-R-NC filters are discussed. The results of experimental study are found to be in good agreement with the theory. The circuit is suitable for fabrication in hybrid integrated circuit technology as it yields better performance than equivalent R-C-NR structures in certain active configurations.     

Simulation of molecular weight distribution and cyclic oligomer formation in the polymerization of nylon 6

The reversible polymerization of nylon 6 including ring opening, polycondensation, polyaddition, and cyclization reactions as well as the reaction with monofunctional acids was simulated for an isothermal batch reactor at 235°C. The cyclic oligomer concentrations, the molecular weight distributions, and its moments have been computed using a chain length-dependent equilibrium constant for the cyclization reaction. Even though the cyclization step does not influence the monomer conversion considerably, it does effect the molecular weight distribution and its moments.     

Potential drops inside MHD generators

This paper presents a theoretical evaluation of the potential drops in various regions taking account of ambipolar diffusion. Temperature dependence of mobility and thermal conductivity have also been taken into account. An expression has been derived for the temperature distribution near the electrodes. Theoretical values of the potential drops have been compared with the experiments and they are found to be in reasonably good agreement. Breakdown potentials have also been calculated and compared with the experiments. It is concluded that inclusion of ambipolar diffusion is essential in the theoretical calculations for the potential drops in MHD generators.     

Quantitative determinations of phenol and resorcinol in pharmaceutical dosage forms by high-pressure liquid chromatography

The quantitative determinations of phenol in phenolated calamine lotion USP and of phenol and resorcinol in phenol-resorcinol-boric acid solution by high-pressure liquid chromatography are reported. The procedures are simple, rapid (no special preliminary treatment is required), and accurate. There is no interference from other ingredients of the lotion (bentonite magma, calamine, and zinc oxide) or solution (acetone and boric acid).     

Confined laminar jet mixing in a circular channel with arbitrary entrance velocity distribution

Summary This paper is concerned with the problem of confined laminar jet-mixing in a circular channel. The Navier-Stokes equations are linearized patterned after an approach proposed bySparrow, Lin, andLundgren in their study of laminar flow development in a channel. After linearization, the governing equation becomes an integro-differential equation. The exact solution is found for the case of two uniform streams each occupying half of a circular channel. Additionally a variational formulation of the same problem is established, completely equivalent to the differential formulation. This variational formulation is constructed based upon the use of convolutions. Approximate variational solutions are obtained. It develops that a simple two-term approximation gives excellent agreement with the exact solution.

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Abgeschlossene laminare Strahlmischung in einem Kreisrohr bei beliebiger Verteilung der Eintrittsgeschwindigkeit

Zusammenfassung Für das im Titel genannte Problem werden die Navier-Stokes-Gleichungen nach einer vonSparrow, Lin, undLundgren vorgeschlagenen Methode linearisiert, wodurch die Grundgleichungen Integral-Differentialgleichungen werden. Für den Fall zweier gleichförmiger Strahlen, von denen jeder eine Hälfte des Kreisrohres einnimmt, wird eine exakte Lösung gefunden. Weiters wird eine Variations-Formulierung desselben Problems angegeben, die der Differential-Formulierung vollkommen äquivalent ist. Näherungslösungen dieser Variationsmethode werden erhalten, und es zeigt sich, daß eine einfache zweigliedrige Näherung ausgezeichnete Übereinstimmung mit der exakten Lösung zeigt.

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With 5 Figures     

Reliability Education in India?Present and Future

This paper surveys the present status and efforts in formal and informal reliability education in India. Survey of important research activities as indicated by the published research papers in this Transactions for the last five years is also included. A three phase programme for future training in reliability for developing countries like India is suggested. Phase one consists of immediate introduction of an elective course for all disciplines of engineering at undergraduate level which should be gradually converted into a compulsory course. Phase two consists of introducing a specialized 2-year postgraduate programe in reliability engineering. Brief course details for both these phases are given. Phase three is the establishment of a National Reliability Research Centre to coordinate, direct, and advance research activities.     

The three-dimensional isoparametric element in curvilinear coordinates

The formulation of the stiffness matrix of an isoparametric element in curvilinear coordinates is presented. The use of curvilinear coordinates eliminates the necessity of introducing intermediate nodes for conforming to curved boundaries. The application of the method to cylindrical coordinates is illustrated by comparing the results for a cylindrical pressure vessel from this formulation with those obtained from the existing solutions.     

A convenient spectrophotometric assay for phospholipase D usingp-nitrophenyl-phosphocholine as substrate

A simple assay for plant phospholipase D is described. The enzyme hydrolyzesp-nitrophenyl-phosphocholine top-nitrophenyl phosphate, which in the presence of an acid phosphatase generatesp-nitrophenol (a chromogenic compound). Thus,p-nitrophenylphosphocholine can be used for assay of phospholipase D in sources that do not also contain high levels of phospholipase C. This work was supported by a U.S. Public Health Service Research Grant (GM15053).     

Effect of Receiver Bandwidth on Waveforms and Time Characteristics of Atmospheric Radio Noise Bursts

Several investigators have presented the results of their experimental investigations and theoretical expectations on the effect of receiver bandwidth on the time characteristics and waveforms of atmospheric radio noise bursts. The experimental and theoretical findings do not appear to agree with each other. This communication offers a possible explanation for this "discrepancy" with support from experimental evidence, drawn from a large number of references included in this communication.