Browsing Faculty Contributions by Publication Date
Now showing items 41-60 of 18490
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Dynamic behavior of mixer-settlers
( Wiley Subscription Services, Inc., A Wiley Company , 1990 , Article)A mathematical model has been developed to simulate and predict the dynamic behavior of liquid extraction counter current operations in mixer-settler units. Murphree efficiency has been included in the model. The behavior ... -
Constituents of plants growing in Qatar XVII anti-inflammatory and cytotoxic activities of extracts of thirty indigenous species
( Taylor & Francis , 1990 , Article)Thirty plants, indigenous to Qatar, were extracted separately with hexane, chloroform and ethanol. The dried extracts were examined for potential anti-inflammatory activities both in vitro by their ability to inhibit ... -
Vegetation composition of a maritime salt marsh in Qatar in relation to edaphic features
( Blackwell Publishing Ltd , 1990 , Article)Coverpercentage values for plant species were estimated using the line-intercept method along two belt transects starting at the lower mangrove frontier and ending at the upper height of the salt marsh. Twelve perennial ... -
Inhibitive Effect of Butyltin Trichloride on Dissolution and Localized Corrosion of Aluminium in Sodium Hydroxide and Hydrochloric Acid
( WILEY-VCH Verlag , 1990 , Article)The dissolution of aluminium in sodium hydroxide and hydrochloric acid in the presence of butyltin trichloride as corrosion inhibitor has been studied by hydrogen evolution and thermometric methods. Experimental findings ... -
Helminth parasites of fishes from two inland lakes in Egypt
( Nihon Kiseichu Gakkai , 1990 , Article)Results of helminthological examination of 1243 fishes, caught from two inland lakes, with unique and contrasting hydrobiological features at Fayoum Governate in Egypt, are presented. General incidence of trematodes, ... -
A review of process and production in SL studies
( Qatar University , 1990 , Article) -
Performance of Greenhouses in The Arabian Gulf
( Qatar University , 1990 , Article)This work is devoted to the gaining of insight into the operation of environmentally controlled greenhouse in hot and humid climates. Field data inside and outside the greenhouse, namely: solar radiation, dry and wet bulb ... -
Constituents of plants growing in Qatar - Part XIX. Flavonoids of Glossonema edule N. E. Br.
( Springer Nature , 1990 , Article)The study of the flavonoids of the unripe fruits of Glossonema edule, resulted in the isolation and identification of apigenin 6,8-di-C-glucoside (violanthin) and luteolin 7-O-glucoside. © 1990 Kluwer Academic Publishers. -
Guaianolides from Centaurea sinaica
( Elsevier , 1990 , Article & Report)Three sesquiterpene lactones were isolated from the aerial parts of Centaurea sinaica: amberboin, chlorohyssopifolin A and sinaicin. The latter is reported for the first time. -
معوقات التنمية الصناعية للقطاع الخاص في دولة قطر
( جامعة الإمارات العربية المتحدة- العين , 1990 , Conference Paper)توجه القطاع الخاص في دولة قطر نحو الاستثمار في القطاع الصناعي بشكل أسرع من ذي قبل بسبب دعوة الحكومة ضمن سياساتها التنموية الجديدة في فترة شهدت ضعفا في الايرادات العامة للدولة بسبب الانخفاض الكبير لأسعار النفط ووصولها الى ... -
Nitron tetrachloroaurate(III) electrodes with poly(vinyl chloride) and liquid membranes for the selective determination of gold
( Elsevier , 1991 , Article)PVC matrix and liquid membrane electrodes have been developed for direct potentiometric determination of gold(III). The membranes incorporate nitron tetrachloroaurate(III) as electroactive material. Fast response for ... -
Thermal dimensional stability of isotropic polyoxymethylene
( John Wiley & Sons, Ltd. , 1991 , Article)A parametric mapping analysis of the effect of various structural and morphological parameters on the thermal dimensional stability of polyoxymethylene is highlighted. The molecular composites model is found to describe ... -
Open-ended cloze procedure and multiple - choice cloze procedure: similarties and differences
( Qatar University , 1991 , Article)This paper is a validation of two cloze procedures: Open-Ended and Multiple-Choice (henceforth OE and MC respectively). Open-Ended and Multiple-Choice tests on the same text were administered to 60 English majors in their ... -
Solidification Of Steel Billets In Continuous Casting
( Qatar University , 1991 , Article)For practical operation, it is necessary to know how the solidification of liquid steel progresses i.e. when and where a strand has completely solidified. Decisions on, the casting speed, the spray water flow rates and ... -
Constituents Of Green Beans Phaseolus Vulgaris (Lipids And Flavonoids)
( Qatar University , 1992 , Article)Chemical study of the lipid fraction resulted in the isolation and identification of a hydrocarbon fraction (n-Czg -0-033); an aliphatic alcohol fraction (C^, Czp, €30) and a sterol fraction (stigmasterol and sitosterol). ... -
Flavonoids from Centaurea sinaica
(1992 , Article)Four Newly isolated flavonoids from Centaurea sinaica -
Liquid and poly (vinyl chloride) matrix membrane electrodes for the selective determination of cocaine in illicit powders
( Elsevier , 1992 , Article)The construction of liquid membrane and PVC matrix-type cocainium ion selective electrodes and their use for direct potentiometry and potentiometric titration of cocaine are described. The ion-pair complexes of cocaine ... -
Poly(vinyl chloride) matrix membrane electrodes for manual and flow injection determination of metal azides
( The Royal Society of Chemistry , 1992 , Article)Novel poly(vinyl chloride) matrix membrane electrodes for the azide ion are developed, electrochemically evaluated and used for manual and flow injection determinations of soluble and insoluble metal azides. These electrodes ... -
Metathesis ring opening polymerization of 5,6-dimethylenebicyclo[2.2.1]hept-2-ene
( John Wiley & Sons, Ltd , 1992 , Article)5,6-Dimethylenebicyclo[2.2.1]hept-2-ene (I) polymerizes in the presence of the two-component ring opening metathesis polymerization (ROMP) initiators WCl6/(CH3)4Sn and MoCl5/(CH3)4Sn. The product polymers were insoluble ... -
Photosynthetic acclimation to high temperatures in wheat
( John Wiley & Sons, Ltd. , 1992 , Article)Growth and photosynthetic performance were assessed for the Finnish wheat Triticum aestivum L. var. APU under a cool (13/10�C day/night) and a warm (30/25�C day/night) regime. Plants exhibited a certain degree of acclimation ...