Browsing Chemistry & Earth Sciences by Publication Date
Now showing items 61-80 of 542
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(−)-Paniculatol, a new ent-labdane bromoditerpene from Laurencia paniculata
( Elsevier Science Ltd. , 1997 , Article)(−)-Paniculatol, 1, an unusual tricyclic bromoditerpene belonging to the ent-labdane series has been identified in the red alga Laurencia paniculata collected on Qatari coasts, Arabian Gulf. The structure displays an unusual ... -
Fatty acid composition of twelve algae from the Coastal Zones of Qatar
( Kluwer Academic Publishers , 1997 , Article)Fatty acid composition of twelve algal species from two different classes were determined. Three Chlorophyta species(Axetabularia calyxulux, Cladophors sericoides and Dictyosphaeria cavernosa) and nine Phaephyta species ... -
Possible evidence for the existence of a hairy layer at the surface of polymer latex particles
( John Wiley & Sons, Ltd. , 1998 , Article)In this work, an attempt is made to verify the existence of a hairy layer at the surface of polymer latex particles, and determine its thickness under different conditions. Two systems have been studied. In one system, ... -
Pinctada radiata (pearl oyster): A bioindicator for metal pollution monitoring in the Qatari waters (Arabian Gulf)
( Springer Nature , 1998 , Article)Bivalves are extensively used in monitoring programmes in the marine environment due to their ability to concentrate pollutants to several orders of magnitude above ambient levels in sea water. Commonly, the levels of ... -
Phospholipid fatty acid composition of nine marine sponges from Qatar
( IFREMER , 1998 , Conference Paper)Phospholipid fatty acid composition was studied in sponge from Qatar including eight Demospongia and one Calcarea. More than 60 fatty acids were identified in each species as methyl esters and N-acyl pyrrolidides by gas ... -
Solid-state planar microsensors for selective potentiometric determination of ethylmorphine
( Marcel Dekker Inc. , 1999 , Article)The potentiometric performance characteristics of microelectronically fabricated solid-state planar ethylmorphine sensors based on silicon/silicon nitride substrate and a mixture of ethylmorphine-tetraphenylborate and ... -
Beach tar contamination on the Qatari coastline of the Gulf
( Elsevier , 1999 , Article)Beach tar concentrations were measured along the Qatari coastlines. Tar concentrations, collected from 11 locations, varied in space and time with values ranging between 2 and 1132 g m−1 (average 290 g m−1) of beach front. ... -
A NEW DEPOSITIONAL MODEL AND SEQUENCE STRATIGRAPHIC INTERPRETATION FOR THE UPPER JURASSIC ARAB "D" RESERVOIR IN QATAR
( Blackwell Publishing Ltd , 2001 , Article)Deposition of the Arab Formation on the Arabian Plate followed a eustatic sea-level high during the Oxfordian that deposited the open-marine shelfal carbonates of the Hanifa and Jubaila Formations. Oolite/peloidal shoals ... -
A new depositional model and sequence stratigraphic interpretation for the upper Jurassic Arab "D" reservoir in Qatar
( Wiley online Library , 2001 , Article)Deposition of the Arab Formation on the Arabian Plate followed a eustatic sea-level high during the Oxfordian that deposited the open-marine shelfal carbonates of the Hanifa and Jubaila Formations. Oolite/peloidal shoals ... -
Constituents of Plants Growing in Qatar, Part XXXI: Lipid constituents of seventeen range plants growing in Qatar
(2002 , Article)A preliminary study on the nutritive values of 17 Qatari range plants -
Photocatalytic degradation of methyl orange as a model compound
( Elsevier , 2002 , Article)Titanium dioxide (TiO2) was used as a photocatalyst for the detoxification of water containing methyl orange (MO), which was used as a model compound. Solar radiation was used as an irradiation source. It was found that ... -
Stratigraphy and sedimentology of the Hofuf Formation in the State of Qatar in relation to the tectonic evolution of the East Arabian Block
( Sultan Qaboos University , 2002 , Article)Well-exposed, fine-grained to pebbly coarse-grained fluvial sandstones of Late Miocene to Pleistocene age crop out in the south-central and south-western parts of Qatar. These sandstones belong to the Hofuf Formation and ... -
Constituents of Plants Growing in Qatar XXXIII Proximate composition of thirty four food and feed plants growing in Qatar
(2003 , Article)34 wild species within 32 genera belonging to 14 families from the flora of Qatar were analyzed for their moisture, lipids, carbohydrate, protein, crude fiber and ash content -
Activation and stabilization of gallium arsenide anode in an aqueous photoelectrochemical cell
( Elsevier , 2003 , Article)The formation of a porous layer on the surface of gallium arsenide anode, n-GaAs, increases photogenerated currents significantly. This layer was formed as a result of an anodic polarization of illuminated n-GaAs in acidified ... -
Chronostratigraphy and geochemical characterization of volcanic rocks from the Hormuz Complex: Constraints from the Halul Island, The State of Qatar
( sultan qaboos university , 2003 , Article)Geochemical and Sr-Nd isotopic data are reported for volcanic rocks in the Hormuz Complex, Halul Island, Eastern Qatar. Two groups of volcanic rocks are distinct in their geochemical characteristics. Group 1 samples have ... -
Activation and stabilization of gallium arsenide anode in an aqueous photoelectrochemical cell
( Elsevier B.V. , 2003 , Article)The formation of a porous layer on the surface of gallium arsenide anode, n-GaAs, increases photogenerated currents significantly. This layer was formed as a result of an anodic polarization of illuminated n-GaAs in acidified ... -
Fatty acids composition of Fifty-one plant species growing in Qatar
(2004 , Article)Fatty acids and lipids composition of fifty one species growing in Qatar belonging to twenty one families and forty three genera are reported -
Spectrophotometric Determination of Hydrogen Peroxide by a Hydroquinone-Aniline System Catalyzed by Molybdate
( Korean Chemical Society , 2004 , Article)In this system hydroquinone is oxidized to pbenzoquinone by H2O2. 2 aniline are added, in successive stages, to pbenzoquinone, to yield the disubstituted quinone as the final product. 20 The UV-VIS spectrum of the product ... -
Effect of octylphenol polyethylene oxide on the corrosion inhibition of steel in 0.5 M H2SO4
( Elsevier , 2004 , Article)A non-ionic surfactant, octylphenol polyethylene oxide (OPPEO), was evaluated as an inhibitor for corrosion of low-carbon steel in 0.5M H 2SO4. Potentiodynamic and potentiostatic methods and scanning electron microscopy ... -
Reduction kinetics of ceria surface by hydrogen
( Wiley Periodicals, Inc. , 2004 , Article)Powdered cerium dioxide (ceria, CeO2) as compressed, sintered pellets, of porosity 16.4% and density 5.99 g cm−3, were treated in hydrogen flow at 1 atm and various temperatures to effect reduction. The electrical conductivity ...