Showing papers by "Cairo University published in 1978"
TL;DR: In this article, a simple algorithm for the self and mutual inductance of coaxial circular coils, based on Bartky's transformation, is presented. But it is not applicable to all coils.
Abstract: A new simple algorithm is presented for the calculation of the self and mutual inductance of coaxial circular coils, based on Bartky's transformation. The algorithm is applicable over the entire range of coil sizes, shapes and degrees of coupling. It is extremely efficient and produces results to a specified and arbitrary accuracy. The method may be extended to calculate the inductance of coils of finite thickness using two-dimensional quadrature formulae.
91 citations
01 Nov 1978
TL;DR: In this article, a canonic active RC circuit for realizing an ideal grounded inductor using a single second generation current conveyor as the active building block is described, which may be considered as a novel active-gyrator circuit realized using only a single current conveying device.
Abstract: A new canonic active RC circuit for realizing an ideal grounded inductor using a single second generation current conveyor as the active building block is described. The circuit may be considered as a novel active-gyrator circuit realized using only a single current conveyor.
61 citations
TL;DR: Dichotomy of lymphocyte populations in lizards is suggested and a peculiar lymphoepithelial macroorgan, resembling the bursa of Fabricius occurs in the colon is suggested.
Abstract: In the lizard, Chalcides ocellatus , the thymus and spleen are similar to those of mammals except that lymphoid tissue of the lizard's thymus and spleen is atrophic in winter. Lizards also possess numerous dense lymphoid nodules associated with the entire gut mucosa and the submucosa of the ileo-colon junction and the caecum. A peculiar lymphoepithelial macroorgan, resembling the bursa of Fabricius occurs in the colon. Oesophageal nodules are few in winter, but their number and size increase in spring and summer and then decrease in autumn. In contrast, lymphoid tissue of the stomach, small and large intestines does not appear to be affected by seasonal variation. Dichotomy of lymphocyte populations in lizards is suggested.
54 citations
TL;DR: In this article, two control strategies are presented for the study of the control of a large-scale electric power system, which are obtained by decomposition of the system to what are called ∊-coupled subsystems, and in the second, a control strategy using closed-loop hierarchical control techniques is introduced.
Abstract: In this paper, two control strategies are presented for the study of the control of a large-scale electric power system. In the first, the control is obtained by decomposition of the system to what are called ‘ ∊-coupled ’ subsystems, and in the second, a control strategy using closed-loop hierarchical control techniques is introduced. Finally, these two approaches are applied to a system consisting of three plants.
46 citations
TL;DR: The thymus in the lizards Mabuya quinquetaeniata and Uromastyx aegyptia is highly involuted in winter but exhibits in the other seasons a rich lymphoepithelial organization.
Abstract: The thymus in the lizards Mabuya quinquetaeniata and Uromastyx aegyptia is highly involuted in winter but exhibits in the other seasons a rich lymphoepithelial organization. The splenic white pulp is severely depleted in winter but is extensively developed in spring, summer and autumn. In these seasons, the splenic lymphoid tissue of Mabuya occurs in a continuous phase throughout the organ obscuring the red pulp, whereas in Uromastyx the white pulp remains localized as periarteriolar aggregates and the red pulp is always clearly delineated. In both lizard species, gut-associated lymphoid tissue is well represented, especially in the large intestines and in Mabuya it is almost similar in different seasons. In Uromastyx, in winter, lymphoid nodules are only found in the caecum and the colon, but during warm seasons, inumerable nodules are distributed throughout the gut. The findings are important for a clearer understanding of immunologic competence in reptiles.
44 citations
TL;DR: In this article, the authors considered treatment contrasts in paired comparison experiments and derived the limiting distribution functions of related likelihood ratio tests for defined local alternatives and their noncentrality parameters, and some optimal design results were obtained.
Abstract: Treatment contrasts in paired comparison experiments are considered. Given that specified orthonormal treatment contrasts are null, remaining treatment parameters, orthonormal contrasts among them, and their logarithms are estimated. The estimators are shown to be consistent and, when suitably scaled and centered, to have distribution functions that are normal in the limit for large sample sizes. Hypothesis tests on treatment contrasts are obtained. The limiting distribution functions of related likelihood ratio tests are derived for defined local alternatives and their noncentrality parameters are shown. The theoretical results are applied to experiments with factorial treatment combinations and some optimal design results are obtained.
39 citations
TL;DR: Based on the experience from 3212 patients with Bilharzial bladder carcinoma a review is given of the pathology, clinical course, treatment and prognosis of the disease.
Abstract: Based on the experience from 3212 patients with Bilharzial bladder carcinoma a review is given of the pathology, clinical course, treatment and prognosis of the disease.
36 citations
01 Jul 1978
TL;DR: In this paper, a second-order sinusoidal oscillator using a single second generation current conveyor is described, where a single grounded resistor adjusts the circuit for oscillation and a single ground capacitor controls the oscillation frequency without affecting the oscilllation condition.
Abstract: A new active RC second-order sinusoidal oscillator using a single second generation current conveyor is described. A single grounded resistor adjusts the circuit for oscillation and a single grounded capacitor controls the oscillation frequency without affecting the oscilllation condition.
34 citations
TL;DR: In this article, a new configuration equivalent to the well known Ford-Girling circuit and using c.c.II instead of the o.a.d.II was presented.
Abstract: A new configuration equivalent to the well known Ford-Girling circuit and using c.c.II instead of the o.a. is given. Applications and advantages of the new realisation are discussed.
30 citations
01 Dec 1978
27 citations
TL;DR: The lipid content and fatty acid composition of six species of bee-gathered pollens, representing five plant families, were investigated and it was indicated that linoleic acid was the major fatty acid of citrus pollen and linolenic of flax pollen.
Abstract: SummaryThe lipid content and fatty acid composition of six species of bee-gathered pollens, representing five plant families, were investigated. Total lipid content ranged from 2·24% in citrus to 4·42% in Egyptian clover. Results of gas-liquid chromatography indicated that linoleic acid was the major fatty acid of citrus pollen and linolenic of flax pollen; broad bean pollen was high in both palmitic and linolenic acids; myristic acid accounted for about half the total fatty acid content of sunflower pollen; the major fatty acid constituents of wild mustard and Egyptian clover pollens were myristic and linolenic acids; arachidic acid, in minor amounts, occurred only in citrus, flax, and wild mustard pollens, and decanoic acid (in trace amounts only) in sunflower and wild mustard pollens. No odd-carbon fatty acids were found in any samples.
01 Sep 1978-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, the kinetics of decarburization and carburization of levitated molten iron-carbon alloy drops at 1650° in CO-CO2 gas mixtures were studied at a pressure of 40 atm.
Abstract: The kinetics of decarburization and carburization of levitated molten iron-carbon alloy drops at 1650° in CO-CO2 gas mixtures were studied at a pressure of 40 atm. The results showed that, under the experimental conditions used, the rates were controlled by transport in the gas phase (decarburization) or by mixed transport control (carburization). The levitated drops behaved as static spherical particles as far as transport in the liquid phase was concerned since the effective diffusivity of carbon in the liquid was close to the atomic diffusivity. The transport model developed in the paper was applied to explain the data from some earlier investigations.
TL;DR: The prooxidative activity of the tested amino acids in general could be attributed to the presence of the a-amino group in the form H3-N-R, mainly due to the functional groups attached in the β-carbon atom in the amino acid molecules.
Abstract: Model systems were designed to study linoleic acid oxidation in the presence and absence of various amino acids with or without cupric ions. The tested amino acids exhibited a potential prooxidant effect in linoleic acid dispersed in aqueous media. The effectiveness of various amino acids on linoleic acid oxidation decreased in the following order: cysteine > serine > tryptophan > phenylalanine > histidine > alanine. The addition of alanine, serine, phenylalanine, histidine, or tryptophan to linoleic acid showed an autocatalytic chain reaction. With cysteine, there was a linear relation between concentration of hydroperoxides and time during the early stages of oxidation. The prooxidative activity of the tested amino acids in general could be attributed to the presence of the a-amino group in the form H3-N-R. The apparent difference in the prooxidative activity is mainly due to the functional groups attached in the β-carbon atom in the amino acid molecules. The addition of cupric ions at a concentration of 10-5M to linoleic acid catalyzed with various a-amino acids showed that these amino acids had no significant effect. Increasing the copper concentration from 10-5M to 10-3M had the following effects: a shortening of the induction period of linoleic acid catalyzed by amino acids having an aromatic side chain, no effect on the induction period but an increase in the oxidation rate during the propagation step in the model systems catalyzed by alanine and serine, and in the model system containing cysteine a linear increase in the linoleic acid oxidation from the start of the reaction.
TL;DR: In this article, a constant density function random number generator was used to predict numerically the effective thermal conductivity of heterogeneous mixtures, which is an extension of a digital simulation technique originally proposed by Baxley and Couper for suspensions and emulsions.
TL;DR: In this article, the 3,5-Diaminopyrazole 1 beim Erhitzen der Pyrazole 3 with Schwefelsaure was introduced, and the 5-Amino-6,7-dihydro-5-methyl-7-oxopyrazolo [1,5a]-pyrimidine was introduced.
Abstract: Pyrimidinderivate und verwandte Verbindungen. VIII. Neue Synthesemoglichkeiten fur 3,5-Diaminopyrazole, 2-Aminopyrazolo[1,5-a]-pyrimidine und 5-Aminopyrazolo-[1,5-a]-pyrimidine
Wahrend die 3,5-Diacylamidopyrazole 2a–c durch Umsetzung von 3,5-Diamino-4-phenylazopyrazolen 3 mit Schwefelsaure und Fettsauren erhalten werden, entstehen die 3,5-Diaminopyrazole 1 beim Erhitzen der Pyrazole 3 mit Schwefelsaure.
2-Amino-6,7-dihydro-5-methyl-7-oxopyrazolo [1,5-a] pyrimidin (4) erhalt man durch Entfernung der Phenylazogruppe des leicht zuganglichen 3-Phenylazoderivates 6.
Die 5-Aminopyrazolo [1,5-a] pyrimidinderivate 12a–c erhalt man in guten Ausbeuten durch Reaktion der 5-Aminopyrazole 10a–c mit Diethyl-β-amino-β-trichloromethylenmalonat 11a. Durch Reaktion von 11b mit 10b entsteht das 5-Amino-6-cyanopyrazolo [1,5-a] pyrimidinderivat 12d.
TL;DR: Pollen from four major plant sources, collected from pollen traps and from cells of the colony, was analysed, finding no appreciable change in the contents of protein, lipid, total reducing sugars, starch, total ash, and individual minerals during storage at temperatures between—5° and 26° C.
Abstract: SummaryPollen from four major plant sources, collected from pollen traps and from cells of the colony, was analysed. There was no appreciable change in the contents of protein, lipid, total reducing sugars, starch, total ash, and individual minerals during storage at temperatures between—5° and 26° C. Variations in mineral content between plant species were found for Ca, Fe and Zn. The plants were Trifolium alexandrium, Zea mays, Vicia faba and Brassica kaber.
TL;DR: A modification of O'Bryan's return-path ellipsometer (J. Opt. Soc. Am. 26 (1936) 122) that extends its applicability to arbitrary surface retardations was presented in this article.
TL;DR: In cases of juvenile diabetes, there were lower than normal levels of reduced glutathione, ceruloplasmin oxidase activity, zinc, copper and sodium, while the other elements show no significant changes.
Abstract: In cases of juvenile diabetes, there were lower than normal levels of reduced glutathione, ceruloplasmin oxidase activity, zinc, copper and sodium, while the other elements show no significant changes. The lower level of serum zinc, copper and sodium may be due to the osmotic diuresis and consequent polyurea of diabetes.
TL;DR: In this paper, the authors considered a class of inhomogeneous elastic halfspaces with the shear velocity and density given by the elasticity equation of motion of elasticity.
Abstract: A class of inhomogeneous elastic halfspaces with the shear velocity and density given by $V\_{\text{S}}^{2}(x\_{2})=V\_{\text{S}\_{\infty}}^{2}+(V\_{\text{S}\_{0}}^{2}-V\_{\text{S}\_{\infty}}^{2})$ e$^{-\epsilon x\_{2}}$, $\rho (x\_{2})=\rho \_{\infty}+(\rho \_{0}-\rho \_{\infty})$e$^{-\epsilon x\_{2}},x_{2}\in [0,\infty]$ are considered. Integral expressions for the surface displacements due to periodic point loads are obtained by directly solving the stress equations of motion of elasticity. Integration over the horizontal wave number $\xi $ is carried out by numerical evaluation along a contour in the complex $\xi $-plane and the response to a pulse type of source is computed by means of the fast Fourier transform (f.F.t.). Theoretical seismograms display a clear refracted P arrival and normally dispersed Rayleigh waves although the onset of S waves is not distinct. An arrival closely following the refracted P wave is observed and seems to fit the characteristics of the pseudo P wave described by Gilbert & Laster (1962). Density variation appears to have little effect on the seismograms, thus indicating that assumptions of constant density in theoretical studies is perhaps reasonable.
TL;DR: Magnetic susceptibility of CH3NH3 and 2FeCl3Br is measured in the temperature range 80-200°K as mentioned in this paper, and a sharp peak characteristic of a spin canted system is found at TN(H=0)=98° K. Magnetic field dependence of the susceptibility and the effect of the halide ion size on the canted spin is discussed.
TL;DR: In this paper, the polarogram of 2-phenylhydrazono derivatives of 3 -phenyl-2,3-diketopropionitrile and 3-ketimino-3-ketobutyronitrile was examined in both acidic and alkaline media.
TL;DR: The present investigation into the effect of amino acids on linoleic acid oxidation in freeze-dried model system illustrates the existence of an autocatalytic chain reaction, in which all amino acids, except cysteine, exhibited minor antioxidant behavior.
Abstract: The present investigation into the effect of amino acids on linoleic acid oxidation in freeze-dried model system illustrates the existence of an autocatalytic chain reaction, in which all amino acids, except cysteine, exhibited minor antioxidant behavior. The antioxidant effect might be attributed to the absence of protonated amino nitrogen. Linoleic acid alone had an induction period of 15 hr, and on the addition of various α-amino acids, the systems had induction periods ranging from 16-19 hr. This increase did not exhibit any specific function for the studied amino acids. Cysteine exhibited an exceptional prooxidant effect due to the role of the HS-group. The addition of copper at concentrations of 10-5M and 10-3M to the model systems composed of linoleic acid and various a-amino acids exhibited minor and highly prooxidant effects, respectively, The prooxidant effect of these amino acids in the presence of copper might be due to amino acids-copper complexes.
TL;DR: In this paper, a method of phase correction in two-integrator loop filters is described in which a single compensating resistor is added in series with one of the two capacitors necessary for implementing the second-order filter section.
Abstract: A method of phase correction in two-integrator loop filters is described in which a single compensating resistor is added in series with one of the two capacitors necessary for implementing the second-order filter section. This method enables perfect phase compensation. Experimental results are presented.
TL;DR: In this article, a modified form of the basic Savage statistic is considered and the performance of a modified Savage (MS) nonparametric detector using this modified statistic is derived, and a detector using a modified rank squared statistic (MRS) is introduced.
Abstract: A modified form of the basic Savage statistic is considered and the performance of a modified Savage (MS) nonparametric detector using this modified statistic is derived. Also, a detector using a modified rank squared statistic (MRS) is introduced. The asymptotic relative efficiency (ARE) of the detectors is determined for chisquare, Rician, and log-normal signal fluctuations when the background noise is assumed Gaussian. The ARE performance of the generalized sign (GS) and Mann-Whitney (MW) detectors is also determined for these families of fluctuations. The ARE performance of the various detectors is then compared, and the results of a computer simulation are presented in which, for a finite number of samples, the performance of the modified detectors is compared with the performance of the GS and MW detectors. It is shown that when using a large number of reference noise samples, the ARE of the GS and MW detectors, the MRS and RS detectors, and the MS and Savage detectors are 0.75, 0.868, and 1, respectively. It is also shown that when using a finite number of reference noise samples the MS and MRS detectors can give a superior performance to that obtained with the MW detector, and that this is particularly true in the cases in which the degree of signal fluctuation is high.
TL;DR: In this article, the polarographic behavior of some p -nitrophenyl-diazo-aryl sulphides in 40% ethanolic aqueous buffers is discussed and the mechanism of electrode processes corresponding to the observed cathodic waves is proposed by means of model compounds and identification of controlled potential electrolysis products.
TL;DR: In this paper, the authors considered the problem of evaluating the fields induced in a long conducting cylinder, with arbitrary cross-sectional shape and arbitrary constant scalar conductivity and permeability, placed in the field of a constant current source.
TL;DR: In this paper a continuous time version of a previous discrete systems optimisation algorithm is developed which uses prediction of costates within a three level structure to provide an efficient organisation of both the storage and the computation.
TL;DR: In this article, an experimental and theoretical investigation of the electronic structure and tautomeric equilibria of 2,4-thiazolidinedione, 4-thiaolidinone-2-thione (rhodanine), 2,thiaodine (isorhodanines), 2.4thiaodesolidinedion, 4thiaodedion, 2.5thiaode, 2.,4thiazlinone-4thion, and 2.2,thiorhodane has been conducted.
Abstract: An experimental as well as theoretical investigation of the electronic structure and tautomeric equilibria of 2,4-thiazolidinedione, 4-thiazolidinone-2-thione (rhodanine), 2-thiazolidinone-4-thione (isorhodanine) and 2,4-thiazolidinedithione (thiorhodanine) has been conducted. The origin of the electronic absorption transitions and the effect of replacing oxygen by sulfur atoms on coplanarity have been discussed. The solvent and pH dependance of the electronic spectra of the studied compounds indicate that there should be a statistical distribution of the ground and excited states between all possible tautomeric structures. This has been confirmed via molecular orbital computations. The calculated pK values have been interpreted with a mechanism based on the calculated deprotonation energies. Results of the present investigation concur with the chemistry of the studied compounds and reveal that these compounds are far from complete homocyclization.
01 Sep 1978
TL;DR: In this paper, a new economical active RC realization of a grounded inductance using the DVCCS/DVCVS as the active element is given, which uses a single grounded capacitor which controls the magnitude of the inductor.
Abstract: A new economical active RC realization of a grounded inductance using the DVCCS/DVCVS as the active element is given. The circuit uses a single grounded capacitor which controls the magnitude of the inductor. Sensitivities to all passive and active circuit components are very low. Application of the simulated inductance in the realization of a canonic selective parallel resonator is discussed.