Showing papers by "Cairo University published in 1982"
223 citations
TL;DR: In this article, the authors present a review of the fuel spray models and discuss the problem of atomization since they affect spray modeling and combustion chamber design, as well as various experimental methods for determining droplet size distribution.
175 citations
TL;DR: Sperm initial motility was significantly decreased in smokers, and the percentage of abnormal forms of spermatozoa was significantly elevated, while there was no significant difference in sperm count between smokers and nonsmokers.
129 citations
01 Dec 1982-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, the electrochemical oxidation of CuFeS2 in various acid solutions was studied using electrodes made from massive samples, and the primary techniques employed were potentiodynamic polarization and constant potential experiments supplemented by capacitance measurements.
Abstract: The electrochemical oxidation of CuFeS2 in various acid solutions was studied using electrodes made from massive samples The primary techniques employed were potentiodynamic polarization and constant potential experiments supplemented by capacitance measurements It was the purpose of this study to investigate the behavior of: (1) several sources of CuFeS2 in H2SO4 electrolytes, and (2) a single source of CuFeS2 in various dilute acids Electrochemical characterization of CuFeS2 from various locations was performed in 1 M H2SO4 which showed significant differences in their behavior All samples exhibited passive-like response during anodic polarization The current density in this passive region was reproducible and showed differences of up to two orders of magnitude between samples from different sources which has been attributed mainly to the presence of impurities in some of the samples During anodic polarization CuFeS2 was found to be sensitive to pH at higher potential, but insensitive at low potential in sulfate solution In addition, current decay measurements at constant potential in the low potential-passive region were found to follow the Sato-Cohen (logarithmic) model for solid film formation Based on current and mass balance measurements, two intermediate sulfide phases appeared to form in the sequence CuFeS2→S1→S2 At higher potentials, in the transpassive region, the observed increase in current is compatible with the decomposition of water to form chemisorbed oxygen which releases copper and forms sulfate ions
106 citations
TL;DR: In this paper, the elastic-plastic behavior of symmetric metal-matrix composite laminates is analyzed for the case of in-plane mechanical loading, and the overall response of the laminate at each instant is derived from the elasticplastic deformation of the individual fibrous layers, and from their mutual constraints.
Abstract: Elastic-plastic behavior of symmetric metal-matrix composite laminates is analyzed for the case of in-plane mechanical loading. The overall response of the laminate at each instant is derived from the elastic-plastic deformation of the individual fibrous layers, and from their mutual constraints. Constitutive equations of the laminated plates are presented in terms of initial yield conditions, hardening rules, and instantaneous compliances. Local stresses, hardening parameters, and strains are found in each lamina and in the fiber and matrix phases within each lamina. Specific results are obtained with the continuum model of elastic-plastic fibrous composites [1] which has been recently developed by the authors. Comparisons of analytical results with experimental measurements are made for certain laminated plates.
92 citations
TL;DR: In this article, an analysis of the problem of self-similar, nonadiabatic blast waves, where both conduction and radiation are allowed to take place, show the problem to be reducible to the integration of a system of six coupled nonlinear ordinary differential equations.
Abstract: An analysis of the problem of self-similar, nonadiabatic blast waves, where both conduction and radiation are allowed to take place, show the problem to be reducible to the integration of a system of six coupled nonlinear ordinary differential equations. Consideration of these equations shows that although radiation tends to produce uniform fields through temperature gradient attenuation, all the energy carried by radiation is deposited on the front and the bounding shock becomes increasingly overdriven. When conduction is taken into account, the distribution of gasdynamic parameters in blast waves in the case of Rosseland diffusion radiation is more uniform than in the case of the Planck emission radiation.
59 citations
TL;DR: In this paper, it was shown experimentally that hard metals have lower frictional resistance than softer metals owing to stronger interatomic linking bonds and hence the resistance to adhesion is increased, providing low frictional characteristics.
50 citations
TL;DR: Misdiagnosis of maxillary sinus hypophasia usually as sinus infection, sometimes as neoplasm, can lead to unnecessary and difficult surgical explorations.
Abstract: Misdiagnosis of maxillary sinus hypophasia usually as sinus infection, sometimes as neoplasm, can lead to unnecessary and difficult surgical explorations. Associated anatomical abnormalities, e.g., caudal displacement of the ipsilateral frontal lobe of the brain or central position in the maxilla of the infraorbital nerve may create unexpected surgical hazards. Associated orbital enlargement can lead to diagnostic confusion in the investigation of headache, especially if the superior orbital fissures show marked asymmetry suggesting erosion. Projection of the fissure into the antrum in Waters view can simulate trabeculation of the sinus or fracture of the inferior orbital rim. Radiologic examination of 500 patients without intracranial or intraorbital lesions revealed maxillary sinus hypoplasia in 36 cases (7.2%) and in half the hypoplasia was unilateral (sinus asymmetry); aplasia was not encountered. Fissure asymmetry was present in 30 cases (6%), being present in 3.66% of patients with normally developed sinuses and in 36.1% of the hypoplasia patients. The appearances and measurements of the fissure are presented and examples of marked normal fissure asymmetry are demonstrated. Maxillary sinus hypoplasia is classified in this series as grade I-mild hypoplasia with limited inferolateral expansion (4 cases) and grade II in which there is also a curved orbital floor and lateral displacement of the adjacent nasal wall (32 cases).
48 citations
TL;DR: A series of 25 cases of pseudarthrotic fibrous tissue with freshening of the bone end was done in all cases and the best results are achieved in cases treated by compression plates and iliac bone grafts.
Abstract: A series of 25 cases of pseudarthrosis of the humeral shaft is presented. These cases were treated by three different methods. The reasons for non-union, the effectiveness of various methods of treatment and the complications are discussed. The best results are achieved in cases treated by compression plates and iliac bone grafts. Excision of the pseudarthrotic fibrous tissue with freshening of the bone end was done in all cases.
48 citations
TL;DR: No distinct trend for the interrelationship between water and tissue elemental concentrations could be established for the regions around Cairo, Aswan and Alexandria.
33 citations
01 Jan 1982
TL;DR: This review attempts to synthesize the existing literature concerning the structure and function of the reticuloendothelial systems of reptiles with the advent of immunohistochemical and in vitro techniques, structural and functional markers of reptilian lymphoid cells can now be identified and characterized.
Abstract: A phylogenetic approach to understanding the development and mechanisms of immunity has gained attention only in recent years. On the evolutionary scale, reptiles are pivotal since they are the progenitors of both avian and mammalian classes. It is now agreed that the basic pattern of adaptive immune responsivity was established when the first vertebrates arose. However, this basic pattern has been constantly altered by evolutionary forces, and thus, the existing reptilian species possess a particular level of organization of their reticuloendothelial systems, much like other organ systems, such as the vascular systems, urogenital systems, nervous systems, etc. In this light, it is important to understand the structure and function of the reptilian immune systems. In particular, these ectothermic amniotes provide an organizational level which could help us to delineate the nature of the immune systems of endotherms. For example, the avian bursa of Fabricius, the generator of B lymphocytes, probably evolved from reptilian ancestors and its equivalent may still exist among living representatives. With the advent of immunohistochemical and in vitro techniques, structural and functional markers of reptilian lymphoid cells can now be identified and characterized. This review attempts to synthesize the existing literature concerning the structure and function of the reticuloendothelial systems of reptiles. Naturally, a major portion of this information has to do with the immune systems proper.
TL;DR: In this paper, the open circuit growth of the thin oxide films on titanium in 0.5N solutions of H2SO4, NaOH, and Na2SO 4 was studied.
Abstract: The open circuit growth of the thin oxide films on titanium in 0.5N solutions of H2SO4, NaOH, and Na2SO4 is studied. The results indicate markedly the dependence of the growth behavior on ...
TL;DR: In this article, the existence of two Brewster angles for surfaces of transparent and absorbing uniaxial crystals parallel and perpendicular to the optic axis has been studied and conditions for their existence have been discussed.
Abstract: Brewster and pseudo-Brewster angles are defined for surfaces of transparent and absorbing uniaxial crystals parallel and perpendicular to the optic axis. Two Brewster angles of a transparent uniaxial crystal surface parallel to the optic axis, measured when the optic axis is oriented perpendicular and parallel to the plane of incidence, readily determine the ordinary and extraordinary indices No and Ne. No and Ne can also be obtained from two Brewster angles measured on a surface perpendicular to the optic axis in contact with two media of different refractive indices. Conditions for the existence of two Brewster angles are discussed. The complex No and Ne of an absorbing uniaxial crystal can be derived from pseudo-Brewster-angle and minimum-reflectance data obtained in two symmetrical orientations of a surface parallel to the optic axis. An approximate, but accurate, explicit inversion procedure is presented for this purpose.
TL;DR: The binding of phenylbutazone and oxyphen butazone to human serum albumin over pH 6.9-9.3 was studied by difference spectrophotometry and equilibrium dialysis.
TL;DR: In this article, the effect of hydrogen bonds on the anisotropy of diamagnetic susceptibility of 2-amino-3-methyl-benzoic acid, 2-hydroxy 3-methylbenzosic acid and o-aminobenzoic acyclic acid has been studied.
TL;DR: In vitro experiments to evaluate the anti-fungal activity of six antimycotic substances found in the preparations currently used for the treatment of otomycosis found the antifungal Activity of clotrimazole and tolnaftate in vitro was evident.
Abstract: One hundred-and eight-six fungi were isolated from one hundred-and-eighty cases clinically diagnosed as otomycosis. They comprise 59 species of 26 genera of moulds, and 2 genera of yeasts. This large variety of mould isolates provided ample material for in vitro experiments, to evaluate the anti-fungal activity of six antimycotic substances found in the preparations currently used for the treatment of otomycosis. The antifungal activity of clotrimazole and tolnaftate in vitro was evident. For over 94 per cent of the 59 fungus species tested, the MIC was less than 0.1 micrograms/ml, and for 6 per cent it was between 0.4 and 1 microgram/ml. Concerning the other 4 antimycotic substances (iodochlorhydroxyquin, fluonilid, natamycine and polymyxin B sulphate) the MIC ranged from greater than 100 micrograms/ml to 1 microgram/ml for the majority of tested fungi. The clinical observations were mostly in accordance with these findings.
DOI•
01 Aug 1982TL;DR: In this paper, the authors reviewed the basic recent developments in the evaluation of Sommerfeld integrals and extended the image approximation of the integrals to include both the earth permeability and the effect of the displacement currents.
Abstract: Some of the basic recent developments in the evaluation of Sommerfeld integrals are reviewed. The image approximation of the integrals is extended to include both the earth permeability and the effect of the displacement currents. The non-uniqueness of the field representation in terms of Hertz vectors is stressed and a proper representation for horizontal dipoles is used. The semi-analytical evaluation of the integrals using the fast fourier transform (FFT) is extended via proper decomposition of the integrand. The analysis increases the range of applicability of these techniques.
TL;DR: Elevated levels of GABA and taurine during hibernation pointed to their role as inhibitory neurotransmitters in the hibernation cycle and induced a noticeable drop in ammonia concurring with increased urea and low uric acid levels.
TL;DR: Twelve genera and thirty-three species of the family Tetranychidae are collected from Egypt and a new genus and twelve new species are described, including four species recorded for the first time.
Abstract: Twelve genera and thirty-three species of the family Tetranychidae are collected from Egypt. Of these, a new genus and twelve new species are described. These are Septobia g.n., Bryobia meyerus sp.n., Septobia bakeri sp.n., S.aegyptiacus sp.n., Petrobia (Mesotetranychus) lycopersici sp.n., Langella summersi sp.n., Aponychus solimani sp.n., Eotetranychus zaheri sp.n., Schizotetranychus tuttleii sp.n., Tetranychus (Tetranychus) attiahi sp.n., T. (Armenychus) ehari sp.n., Oligonychus (Reckiella) sayedi sp.n. and O. (Reckiella) krantzi sp.n. Four species are recorded for the first time: Tetranychina marsai (Manson), Oligonychus (Oligonychus) punicae (Hirst), O. (Reckiella) afrasiaticus (McGregor) and O. (Reckiella) pratensis (Banks). A female of unknown species of the genus Schizotetranychus is also described and keys to the genera and species are given.
TL;DR: In this article, a condensed review of finite element applications in metal forming processes is presented, which is based on a convenient explicit form of the hydrostatic-pressure load correction stiffness matrix for isoparametric and allied types of elements.
TL;DR: In this paper, a study of the various parameters present in each method which may influence the strain localisation process indicates that the overall strain gradient across the bulged testpiece is responsible for the higher strain limits.
TL;DR: It is believed that frequent antral irrigation and local instillation of a broad-spectrum antimycotic drug--preferably after debridement--is the treatment of choice for antromycosis.
Abstract: Increasing numbers of cases of chronic maxillary sinusitis are encountered which resist frequent sinus irrigation and treatment of predisposing factors The antral washouts are of unusual consistencies and colours The antral washouts of six cases were investigated by culture and microscopic examination and proved to contain fungal colonies Antroscopy was a valuable asset in diagnosis One patient had a Caldwell-Luc operation and daily irrigation through an indwelling polythene tube followed by daily instillation of clotrimazole (Canesten) The five patients who refused operation were treated by repeated bi-weekly antral washouts followed by instillation of clotrimazole Weekly samples of antral secretions were examined by culture and microscopic examination until they were free for four consecutive weeks We believe that frequent antral irrigation and local instillation of a broad-spectrum antimycotic drug--preferably after debridement--is the treatment of choice for antromycosis
TL;DR: In this paper, the formation constants of N-(2,3-dimethyl-1-pheny1-5-oxo-3-pyrazoline-4-yl)-N′-benzoylthiourea with 3d transition metal ions [Cu(II), Ni(II, Zn(II) and Mn(II)] have been determined in 70% ethanol-water medium.
Abstract: The formation constants of N-(2,3-dimethyl-1-pheny1-5-oxo-3-pyrazoline-4-yl)-N′-benzoylthiourea with 3d transition metal ions [Cu(II), Ni(II), Zn(II) and Mn(II)] have been determined in 70% ethanol-water medium. The effect of metal ion, ionic radius and electronegativity on the formation constants are discussed. The formation constants follow the order Mn Zn. A cobalt complex has been isolated and characterized by conductance, IR and magnetic moment. The ligand forms tris-complex of octahedral arrangement and has the general formula CoL3, where L is the uninegatively charged bidentate ligand (O S donor set).
TL;DR: Results indicated the alteration in tryptophan metabolism are usually well compensated in the non-depression group but may accentuate or precipitate the development of depression in susceptible women.
TL;DR: Two quenched plain-carbon steels containing 0.5% and 0.8% C have been subjected to tempering in the temperature range 100-700°C as discussed by the authors.
TL;DR: The reaction of ethyl cyanoacetate with α-cyanochalcone (1) leads to the formation of β-enaminoesters (3) via Michael addition.
Abstract: The reaction of ethyl cyanoacetate with α-cyanochalcone (1) leads to the formation of β-enaminoesters (3) viaMichael addition. Compound3 reacts with phenylmagnesium bromide to give the β-enaminoketone5. Acetylation of3 gives the acetyl product4. Each of compounds1 and3 reacts with malononitrile to give β-enaminonitrile6. Phenylhydrazine reacts with3 to give the hydrazone7. Similarly 3-phenyl-5-aminopyrazole reacts with3 to give theSchiff base8.
TL;DR: In this article, a mechanism was proposed and it was substantiated by synthesis of 6a from N-(2-car☐yphenyl)-C-phenylcarbamoyl hydrazidoyl chloride 8a or its N-( 2-methoxycarbonyl carbonylphenyl) analogue 8d.
TL;DR: In all cases in which Actinomyces or bacteria were present histopathologically, a minimal tissue response indicated that these organisms were saprophytes and not primary pathogens.
Abstract: Tissues from 227 tonsillectomies, mainly in adults, were examined culturally and histopathologically for the presence of fungus. Actinomyces was demonstrated in 69 cases (30.40 per cent) by both methods. Yeasts and moulds were each isolated from 21 cases (9.25 per cent) and mixed isolates were obtained from 7 cases (3.08 per cent). There was no histopathological evidence of these organisms. Negative cultural and histopathological results were obtained in 53 cases (23.35 per cent). Chloramphenicol-resistant bacteria were cultured in 56 cases (25.11 per cent) but were seen histopathologically in only 25 cases (11.01 per cent). In all cases in which Actinomyces or bacteria were present histopathologically, a minimal tissue response indicated that these organisms were saprophytes and not primary pathogens.
TL;DR: The embryology of Hyalomma dromedarii was investigated by studying serial sections of softened chorion eggs and the embryo size changes were recorded.
Abstract: The embryology of Hyalomma dromedarii was investigated by studying serial sections of softened chorion eggs. Embryo size changes were recorded. Cleavage began within 3 hrs after oviposition and was indicated by vitellophages of different sizes. Average egg size (AES) during cleavage was 0.98 × 0.97 mm. Mitotic division and nucleus migration continued for 8 days until blastoderm formation (AES 1.06 × 0.93 mm). Primordia and layers formed on day 10 when the egg became spherical (AES 1.07 × 1.07 mm). Differentiation of the germ band to capitulum, ambulatory and opisthosoma segments was on day 12 (AES 1.32 × 1.1 mm). During this stage the embryo enlarged. Nervous system tissues became apparent on days 14–15; the differentiated germ band elongated and the embryo size was reduced (AES 1.04 × 0.96 mm). The digestive system, rectal sac, and anus appeared on day 16 after oviposition and the embryo became elongated (AES 1.38 × 1.08 mm). On day 17–18, the appendages, nervous tissues, and rectal sac were for...