Browsing Qatar University Science Journal - [From 1981 TO 2007] by Publication Date
Now showing items 1-20 of 770
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The Neurosecretory Cells and Neurosecretions in the Developmental Stages of the Cotton Leafworm -Spodoptera Littoralis (B)
( Qatar University , 1981 , Article)In 1955 Nayar described two types of neurosecretory cells in lphita limbata (A- and B-types) [1]. Later, Johannson [2] classified these cells into four categories: A, B, C and D, which he regarded as motor neurones of ... -
Dehydration of Ethanol over HF-treated Al2 O3 using the GC-column as Chemical Reactor
( Qatar University , 1981 , Article)The effect of treating •y-alumina with hydrofluoric acid on the dehydration reaction of ethanol was investigated at 325°C. The gas chromatographic column was used as a chemical reactor. The rate of formation of ethylene ... -
Translation - invariant Positive-definite Generalized Kernels of Infinite Number of Variables
( Qatar University , 1981 , Article)In the theory of spectral analysis of positive-definite j<.ernels, there exist well-developed methods based on the ideas of Krein connected with the construction of a Hilbert space by means of a kernel [ 1, 11]. In the ... -
Mossbauer Effect Study of Libyan Desert Silica Glass
( Qatar University , 1981 , Article)The Mossbauer effect and X-ray fluorescence techniques are applied to study the Libyan Desert Silica Glass. The X-ray flourescence proved the existence of 13 elements in each sample of five glass types with differences in ... -
On the Propagation of Elastic-plastic Wave in the Half Space
( Qatar University , 1981 , Article)The problem of the propagation of the elastic-plastic wave in the half-space occupied by and elastic-plastic medium has been studied. Treatments were carried out under the Assumption of perpendicular load, on the boundary, ... -
p,q Ideal of Operators in Banach Spaces
( Qatar University , 1981 , Article) -
Mechanism of Dehydration of Ethanol over Alumina
( Qatar University , 1981 , Article)The dehydration reaction of ethanol to ether and ethylene was kinetically investigated in a flow system using •y-alumina. Pyridine was found to inhibit the formation of ethylene and ether. The rate of ethylene formation ... -
استخدام ظاهرة الرنين النووي (ظاهرة موسباور) في مجمال دراسة فخار الآثار القديمة
( Qatar University , 1981 , Article)أصبح استخدام الطرق العلمية الموضوعية لازماً لتأكيد النتائج الذاتية التي يتوصل إليها علماء الآثار، وطريقة طيف موسباور المستخدمة في البحث الحالي تعتبر أحدث الطرق العلمية الفيزيائية التي استخدمت في مجال دراسة الفخار الذي عثرت ... -
Relation between Quasi-normed Ideals of Entropy Numbers and of Approximation Numbers
( Qatar University , 1981 , Article)Let en(T) and an(T) be the entropy numbers and approximation numbers of operator T between Banach spaces, respectively. Let ?p be the operator ideal defined by Sp:^TeL;{en(T)^lp}, and Sp be the operator ideal defined ... -
Overhead Allocation: a Goal Programming Approach
( Qatar University , 1981 , Article)Overhead is an incurred cost which is matched against cost objects via an intervening base of allocation. The problem of overhead allocation is to come up with a cost allocation procedure which is objective, applies, ... -
Mossbauer Effect Study of the Hyper fine Structure of the Different Phases of Iron in the Portland Cement Produced in Qatar
( Qatar University , 1981 , Article)Various samples of the raw materials used in the manufacture of Portland cement in Qatar, the clinker produced and the cement itself were studied by using Mossbauer Effect and X-ray diffraction analysis in order to investigate ... -
Petrophysical Studies on Samples from Eocene Exposures West Cairo-Egypt
( Qatar University , 1981 , Article)The present work deals with petrophysical and petrochemical studies on 58 limestone samples of Eocene age in two localities west of Cairo (Sakkara and Giza Pyramids Plateau). The determined petrophysical properties are: ... -
Primary Productivity of Lake Manzalah, Egypt, using C14 technique
( Qatar University , 1981 , Article)The hydrographical and chemical conditions of Lake Manzalah, Egypt, are influenced by the surging in of saline water from the Mediterranean sea and are by no means stable. The average of the parameters studied during the ... -
Study of Magnetic Properties and Lattice Dynamics of the Cdx Co1-x Ferrite System by MossbauerEffect
( Qatar University , 1981 , Article)The magnetic properties and lattice dynamics of the spinel ferrite system Cdx Coi-x Fe^ 04 (x = 0.0, 0.1, . . . , and 1.) were studied in the temperature range between 78 to 800°K. The results showed that the samples with ... -
Study of the Hydration of Blast-Furnace Slag Cement and Portland Cement by Mossbauer Spectroscopy
( Qatar University , 1982 , Article)Mossbauer spectra have been measured for the hydrated blast-furnace slag cement and Portland cement pastes at different times of hydration of 1. 3. 7. 28 and 90 days. The spectra showed the existence of iron atoms, Fe3 (T) ... -
Insect Pests Attacking Vegetable Crops in the State of Qatar (Abstract)
( Qatar University , 1982 , Article)The area cultivated with vegetable crops in the State of Qatar reached, during 1979 and 1980, a percentage of about 42.9 % of the total cultivated (or suitable to be cultivated) area. Vegetable crops selected for collecting ... -
Neutron Diffraction and Mossbauer Effect Study of a Cobalt Substituted Zinc Ferrite
( Qatar University , 1982 , Article)The mixed cubic ferrite Zno.g5 €00.15 Fez 04 is studied by neutron diffraction and Mossbauer effect techniques at the temperature range 4.2 - 293 °K. The obtained spectra by both methods at low temperature show a long range ... -
Bionomics of the Shrimp Fishery in the Inshore Waters of Qatar
( Qatar University , 1982 , Article)The shrimp fishery in Qatar is carried out by artisanal crafts, operating from Doha and Al Khor on the East coast. The fishing is restricted to the 2-6 Fm depth range and Penaeus semisulcatus forms about 95 % of the shrimp ... -
Stability Constants of Lanthanide Complexes with some Structurally Related Organic Ligands
( Qatar University , 1982 , Article)The stability constants of the complexes formed between trivalent lanthanide ions and related carboxyphenylhydrazo-B-diketones ligands are repoted, at 30 °C and at constant ionic strength (0.1 KN03), in 75 % dioxane-water. ... -
Studies on Soil Cements: 1 - Role of Hydrated Lime and Dolomitic Monohydrate in Montmorillonite Stabilization
( Qatar University , 1982 , Article)Montmorillonite clay was stabilized by either hydrated lime or the dolomitic monohydrate (Ca(OH)2. MgO) during suspension hydration at 25 and 60°C for 45 days. The distinct phases produced from the hydration of each ...
