Now showing items 1-20 of 7462

    • Synthesis and biological activity of some new 3-and 6-substituted coumarin amino acid derivatives. Part I 

      El-Naggar, A. M.; Ahmed, F. S. M.; El-Salam, A. M. A.; Radi, M. A.; Latif, M. S. A. ( Wiley-Blackwell , 1981 , Article)
      The synthesis of 6-nitrocouarrain-3-CO-amino acids and their corresponding methyl esters (II-XVII) and some dipeptide methyl esters (XVIII-XXVI) are described. 6-(N-Tosyl- or N-phthalylaminoacyl)aminocoumarin-3-carboxylic ...
    • Synthesis and biological activity of some new aminoacylcarbazole derivatives. Part I 

      El-Nagger, A. M.; Ahmed, F. S. M.; El-Salam, A. M. A.; El-Gazzar, M. A. ( Wiley-Blackwell , 1982 , Article)
      The syntheses of different 9-(N-phthalyl- or N-tosyl- or free aminoacyl)carbazoles and the corresponding derivatives of 3,6-dinitrocarbazoles and some derivatives of 3,6-diamino-9-(N-phthalylaminoacyl)carbazoles (II-XXXII) ...
    • Absolute evaluation of ferrous and ferric concentration in Ca amphibole 

      Bahgat, A. A.; Fayek, M. K. ( WILEY-VCH Verlag , 1982 , Article)
      Studies are made of M?sshauer absorption of 57Fe in a Ca-amphibole schist sample at room and liquid nitrogen temperatures. The absolute concentration and the recoilless fraction for ferrous and ferric cations are determined ...
    • THE TRANSFER OF PSYCHOLOGICAL KNOWLEDGE TO THE THIRD WORLD COUNTRIES AND ITS IMPACT ON DEVELOPMENT: THE CASE OF FIVE ARAB GULF OIL-PRODUCING STATES 

      Melikian, L. H. ( Elsevier Science Publishers B.V. , 1984 , Article)
      Psychological knowledge transmitted by universities in Bahrain, Kuwait, Qatar, Saudi Arabia and the United Arab Emirates is presented and some historical-cultural roots identified. Required courses for a B.A. are similar ...
    • Ventifacts distribution in Qatar 

      Babikir, A. A. A.; Jackson, C. C. E. ( John Wiley & Sons, Ltd , 1985 , Article)
      This study attempts to investigate the distribution of ventifacts in Qatar. It is believed that ventifacts are confined to the areas within about 5 km of the Miocene or Mio-Pliocene Hofuf formations and the spreads of ...
    • Mössbauer study of ZnxNi5/3−xFe1Sb1/3O4 spinel ferrite 

      El Nimr, M.K.; Saleh, H.A.; Fayek, M. K. ( Springer Verlag , 1985 , Article)
      The antimony substituted nickel ferrite ZnxNi5/3–xFe1Sb1/3O4 with different values ofx are prepared, checked by x-ray and studied with57Fe Mössbauer spectroscopy over a wide temperature range. Characteristic spectra of ...
    • Mössbauer effect study of Li21+Me4+Fe63+O122−spinels 

      Saleh, H.A.; El Nimr, M.K.; Nada, N.; Fayek, M. K. ( Baltzer Science Publishers, Baarn/Kluwer Academic Publishers , 1986 , Article)
      Mossbauer effect spectra are obtained for the cubic ferrites Li2 Me Fe6 O12 (where Me4+ is one of the tetravalent elements Ge, Si and Ti) at 78K up to their magnetic transition temperatures. In a rather large temperature ...
    • Polarization Resistance Study on Copper Corrosion in Aqueous Potassium Hydrogen Phthalate Solution 

      Mouhad, M. Y.; Bekheet, A. M.; Soliman, S. A. ( WILEY-VCH Verlag , 1987 , Article)
      The effect of temperature on corrosion of copper in 0.1 M aqueous solution of potassium hydrogen phthalate (KHPh) has been investigated using polarization resistance technique. it was found that that the corrosion rate in ...
    • M-Profile ray tracing technique for multipath propagation 

      Kheirallah, H.N.; Rashwan, H.M.; Aboul-Saoud, A.K. ( IET , 1987 , Article)
      A model for the modified refractivity is suggested and used in a new and simple ray tracing approach for multipath propagation. The technique is then used to study the variations in ray path parameters for different path ...
    • On the Design of Bit-Slice Processors 

      Bishai, S.; Metwally, M. S. ( Qatar University , 1988 , Article)
      In the past decade, fixed instruction microprocessors have evolved from 4 bits to 32 bits. Their compact design and relative low cost have made them very popular with design engineers. Their use extends into a lot of ...
    • A study of the interlanguage of some Arabic students of English 

      Al-Buainain, Haifa ( Qatar University , 1988 , Article)
      In this study, the contrastive analysis method is used to investigate the lnterlanguage (IL) developmental sequences of the acquisition of some aspects of English by Arabic-speaking learners. The learners, whose language ...
    • A short critique of the Crescent English Course 

      Al-Buainain, Haifa ( Qatar University , 1988 , Article)
      This paper is a short critique of the "Crescent English Course", Pupils Book 2. It falls into two parts. The first is information about the course; its aims, organization and some of its general characteristics. The second ...
    • Performance Evaluation of A Class of Adaptive Bifurcated Routing Algorithms 

      Ayad, N. M.; Mohammed, F.A.; Metwally, M.S. ( Qatar University , 1988 , Article)
      With the cost of computation decreasing, packet-switched computer communication networks are becoming increasingly cost effective. In this paper a class of bifurcated routing algorithms is considered. One of the algorithms ...
    • Evidence for some prostaglandins in Allium sativum extracts 

      Al-Nagdy, Sohair A.; Abdel-Rahman, M. O.; Heiba, H. I. ( John Wiley & Sons, Ltd. , 1988 , Article)
      Homogenized garlic (Allium sativum Linn.) was extracted successively with organic solvents and the prostaglandin-rich fraction separated. Fractionation of the extract with column chromatography was performed. TLC of the ...
    • Effects of herbicide and timing of removal on interference between barley and weeds 

      ISMAIL, A. M. A.; HASSAN, A. H. A. ( Blackwell Publishing Ltd , 1988 , Article)
      Field experiments were done during the rainy season of 1984�85 and 1985�86 at Harma, Qatar. A weed survey of barley fields was conducted with the primary purpose of identifying the weed vegetation present. The effects of ...
    • Distribution and ultrastructure of neurosecretory cells in the cerebral ganglion of the earthworm 

      Al-Yousuf, S. ( Wiley Subscription Services, Inc., A Wiley Company , 1988 , Article)
      Neurosecretory (Nsy) cells within the cerebral ganglion of Lumbricus terrestris were classified ultrastructurally. The Nsy cells within the subesophageal ganglion, nerve cord ganglion, and the peripheral nervous system ...
    • Substituted phenols as corrosion inhibitors for copper in nitric acid 

      Fouda, A. S.; Mohamed, A. K. ( WILEY-VCH Verlag GmbH , 1988 , Article)
      The dissolution of copper in nitric acid solution in the presence of resorcinol, o, p-aminophenols, catechol, o-cresol and salicylaldehyde as corrosion inhibitors has been studied by galvanostatic polarization and weight ...
    • DESIGN AND UTILIZATION OF A LOW-COST FLEXIBLE MANUFACTURING CELL 

      Abdelrahman, Tarek M.; Roushdy, Essam H. ( IEEE , 1988 , Conference Paper)
      This paper describes how to establish and efficiently utilize a low-cost Flexible Manufacturing (FM) cell for education, light machining and assembly operations. The cell comprises a microcomputer, manufacturing workstations, ...
    • Study of A Time Dependent Double -Diffusive Salinity Problem 

      Tag, I.A.; Hassab, M.A. ( Qatar University , 1989 , Article)
      The time-dependent, double diffusive stability problem for a horizontal layer of salty water bounded by two rigid isothermal surfaces is analyzed using a linear perturbation technique. Initially, the layer is subjected to ...
    • Diffusion of saturated hydrocarbons in low density polyethylene (LDPE) films 

      Asfour, A.-F. A.; Saleem, M.; Kee, D. D.; Harrison, B. H. ( Wiley Subscription Services, Inc. , 1989 , Article)
      The diffusion coefficients at zero penetrant concentration, D0, of n-heptane, n-heptane, n-octane, n-decane, and 2,2,4-trimethylpentane (TMP) in LDPE were obtained in the range of 25–50°C, using the desorption method. The ...