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The present work describes a method to develop a simulation model for dearomatisation of the straight-run fraction that boils in the range 140–240°C (also called Aviation Turbine Fuel fraction) of Bombay high crude (India—offshore). Sulpholane was used as a solvent to extract aromatics from this fraction. A mass spectrometric analysis of the ATF fraction identified six hydrocarbon types; each of these was represented by one or more components. The group contribution model, UNIFAC, has been investigated for the prediction of the multicomponent liquid—liquid equilibria. The compositions of the extract and raffinate phases, thus predicted, compare closely with single stage experimental data. Multistage countercurrent extraction calculations have also been carried out using the above model and checked satisfactorily against experimental data that were available on a 27 mm-diameter packed laboratory extraction column. It has been shown that the representation of ATF fraction by model hydrocarbons, together with the equilibria predictions by UNIFAC, form a sufficiently accurate data base for the simulation model.

The entry flow into a circular tube of slowly varying cross-section is studied by considering the flow field to consist of two regions—a core region and a boundary layer region. As in classical boundary layer problem, the equations in the two regions are solved separately using a matching condition at the edge of the boundary layer. For different wall geometries, the velocity, shearing stress and vorticity are computed and the phenomenon of boundary layer separation is discussed. It is found that the shape of the wall geometry plays an important role on the fluid dynamic characteristics. The model is quite versatile and can be applied to a variety of engineering problems involving slowly varying, converging or diverging tubes.

A series of starch-g-polyacrylonitrile copolymers of starch granules and starch gel were synthesized with the Mn3+ initiating system. The samples were examined and photographed in a scanning electron microscope before and after homopolymer extraction in N, N-dimethylformamide., The grafted starch was hydrolyzed in aqueous acid solution to remove the starch moiety. The graft copolymers were also saponified with aqueous sodium hydroxide to convert nitrile groups to carboxamide and sodium carboxylate groups. The micrographs show that polyacrylonitrile is grafted both on the surface and in the interior of the granule. At higher grafting ratios the products contain increasing amounts of grafts inside the granule, but the centre of the granule is always hollow. The saponified graft copolymer retains its granular structure, in spite of the swelling and the high temperature during the hydrolysis, although the surface of the granules becomes smoother. Morphologische Untersuchungen von durch Pfropfung unter Verwendung von Mn3+ -Reaktionsinitiator und durch Verseifung modifizierter Kartoffelstarke. Eine Reihe von Starke-g-Polyacrylnitril-Copolymeren von Starkekornern und Starkegel wurden mit Hilfe des Mn3+ -Reaktionsinitiator-Systems synthetisiert. Die Proben wurden untersucht und vor und nach der Homopolymer-Extraktion in N, N′-Dimethylformamid in einem Raster-Elektronen-mikroskop photographiert. Die gepfropfte Starke wurde zur Entfernung des Starkeanteils in wasriger Saurelosung hydrolysiert. Die Pfropf-Copolymere wurden auch mit wasriger Natriumhydroxid-Losung verseift, um die Nitrilgruppen in Carboxamid und Natriumcarboxylatgruppen umzuwandeln. Die Mikrofotographien zeigen, das Polyacrylnitril sowohl an der Oberflache als auch im Innern des Korns gepfropft ist. Bei hoheren Pfropfungsgraden enthalten die Produkte zunehmend Pfropfungen innerhalb des Korns, jedoch ist das Zentrum des Korns immer hohl. Das verseifte Pfropf-Copolymer behalt seine kornige Struktur trotz Quellung und hoher Temperatur wahrend der Hydrolyse, obgleich die Oberflache der Korner weicher wird.

The dynamic response of electrons to an oscillating charge source in a bimetallic system is treated in the hydrodynamic approximation. Results for the induced potentials are given for planar as well as spherical junctions, and are employed to evaluate the van der Waals interaction of a molecule with the interface. The dispersion formulae for interface plasma oscillations are discussed for both planar and spherical geometries.

The free electron contribution to the workfunction of metals is estimated using the linearised hydrodynamic model. It is shown to be inversely proportional to square root rs. Numerical values obtained for various metals show reasonable agreement with experimental results, as also with previous theoretical predictions based on the density functional approach, despite the simplicity of the model.

A technique for parallel backtracking using randomization is proposed. Its main advantage is that good speedups are possible with little or no interprocessor communication. The speedup obtainable is problem-dependent. In those cases where the problem size becomes very large, randomization is extremely successful achieving good speedups. The technique also ensures high reliability, flexibility, and fault tolerance. >

Thia paper is concerned with the design of model reference adoptive control systems for a class of non-linear plants. The proposed method utilizes Liapunov's direct method for the derivatio n of a relatively simple adaptation rule. The stability of the overall system is assured by imposing a suitable Liapn nov function on the sy3tsm.

(1965). The development of the Indian outlook on world affairs before 1947. The Journal of Development Studies: Vol. 1, No. 3, pp. 269-294.

1. Es wurde eine experimentelle Untersuchung uber das Koagulationsvermogen verschiedener Elektrolyte auf die Sole von Chromihydroxyd und Kupferferrocyanid in Gegenwart stabilisierender Ionen ausgefuhrt.

(1963). On the use of the term ‘commonwealth’. Journal of Commonwealth Political Studies: Vol. 2, No. 1, pp. 1-16.

Es sind Adsorptionsversuche ausgefuhrt worden mit frischgefallter und gut ausgewaschener Kieselsaure und Essig-, Propion-. Butter-, Citronen-, Benzoe-, Salicyl-, Hippur-, Schwefel-, Salpeter- und Chlorwasserstoffsaure. Die prozentische Menge der Adsorption bei diesen Sauren geht nicht uber 2,7 hinaus.

We point out: (i) a pseudo-hermitian Hamiltonian has conjugate-energy states if its complex eigenvalues do not belong to the residual spectrum of its adjoint, (ii) particle-antiparticle symmetry puts certain restrictions on the decay channels if there are to be no negative norm, real-energy states, and (iii) exponential time dependence of decays is valid for a pseudo-hermitian Hamiltonian if the initial conditions are chosen with care.

1. Die Peptisation von Eisen- und Chromhydroxyd in Gegenwart von uberschussigem Alkali und arseniger Saure, Rohrzucker und Glyzerin ist quantitativ untersucht worden. 2. Es wird gezeigt, das keine einfache Beziehung besteht zwischen der Menge des peptisierten Hydroxyds und der der schutzenden Substanz. Das Verhaltnis Metallhydroxd/schutzende Substanz variiert nicht nur mit der Konzentration des Metalls, sondern auch mit dem Ueberschus an freiem Alkali und in einigen Fallen auch mit dem Volum des Gesamtsystems. 3. Die Bildung einer definierten Verbindung zwischen dem peptisierten Metallhydroxyd und der schutzenden Substanz ist deshalb sehr unwahrscheinlich. 4. Arsenige Saure hat im Gegensatz zu den Nichtelektrolyten auch ohne Alkalizusatz peptisierende Wirkung infolge ihrer Fahigkeit, leicht adsprbierbare Ionen abzugeben. 5. Es wird gezeigt, das der Alkaliuberschus ein gewisses Minimum nicht unterschreiten darf, wenn arsenige Saure, Rohrzucker oder Glyzerin das Hydroxyd vor der Fallung schutzen sollen. 6. Der Alkaliuberschus hat fur die im vorliegenden beschriebene Peptisation fundamentale Bedeutung. Es ist sehr wahrscheinlich, das die OH-Ionen das peptisierende Agens darstellen, wahrend die Nichtelektrolyte diese Peptisation nur indirekt unterstutzen. In jedem Falle ist die beobachtete Schutzwirkung als gemeinsame Wirkung von Alkali und Nichtelektrolyt anzusehen.

Mortierella indica Mehrotra was the first report of a fully described species of the genus in India (Mehrotra, 1960). A number of species of Mortierella have been isolated. Two of the new ones having certain features in common are described here. Both species have a subsporangial swelling; in one this occurs just below the sporangium, in the other, slightly below it. The branches from the sporangiophores almost exclusively have been found to arise from this vesicular swelling in both species. This feature never has been reported in either the genus Mortierella or in any other genus of the Mucorales. Recently Ribaldi (1952) created the genus Gongronella in the family Mortierellaceae. The main basis for this genus was the presence of a subsporangial vesicle. Soon after, Peyronel and Dal Vesco (1955) and later Picci (1955) transferred Absidia butleri Lendner to the genus Gongronella mainly on the basis of the presence of a well-marked subsporangial vesicle and pointed out that the type species, Gongronella urceolifera Ribaldi, is very similar to Gongronella butleri. Smith (1961) transferred Mucor vesiculosus Smith to Gongronella butleri. In the list of synonyms of Gongronella butleri, Smith included Gongronella urceolifera as well. The principal characters on which A. butleri was transferred to the genus Gongronella were the subsporangial swelling and the absence of appendages surrounding the zygospores, although this latter condition also exists in at least one known species, A. blakesleeanus Lendner (1923). From a practical standpoint, the genera of Mucorales are based on asexual characteristics rather than sexual ones.

The induced potential due to an oscillating charge source near the interface of two metals whose electron densities differ slightly, is calculated in the hydrodynamic approximation. Results are given for both planar and spherical interfaces. The potential is used to evaluate the dispersion force field on an atomic system near the interface. It is shown that the force field is divergence-free at very small separation from the planar interface if the electron density profile is diffuse.