Vol. 15 Issue 3
Nurfer Gungor
The effect of the exchangeable cations upon the gel structure of slurries obtained from two different types of bentonites found in Turkey and identified as swelling and non-swelling were determined. NaCl, KCl and CaCl2 of varying concentrations were added to these slurries and their effects on the rheological properties were determined. The results of this investigation highly suggests that the resulted swelling thixotropic gels depends mainly on the exchangeable cations added.
A.M. Gheith and M. Abou ouf
Two vertical sections were made in the Tertiary coastal hills near Jeddah. Their lithology was studied and sediment samples were taken concurrently for grain size and mineralogical analyses. Their depositional environments, paleogeography and source rocks, deduced from their sedimentological, mineralogical and petrological characteristics are discussed herein.
The sequences represent alluvial terraces and fan deposits typical of debris flows. They are comprised of poorly sorted, subrounded to rounded pebbles and cobbles embedded in a coarse-grained sand and clay matrix with generally inclined planar bedding. They were probably laid down in a braided-stream environment and may represent alluvial deposits of a proto-Wadi Fatima. The alluvial recorded is characterized by drainage lines generally active enough to cut the basement rocks as indicated by high epidote content. These hills document the uplift of a Red Sea Escarpment considerably after deposition of the Jizan group.
Repeated cyclic variation with a dominant regressive phase and a period of non-deposition interrupted by volcanism probably indicates a post Oligocene drainage system.
Hamed A. El-Nakhal
In Yemen, the Paleozoic Erathem includes the Wajid Formation which consists of continental sandstone (Carboniferous-Early Permian) and the Kooli Formation which consists of glacial siltstone and silt-shale (Permian). The Kooli is the lower formation of the Kohlan Group (Permian-Early Jurassic) and it is subdivided into the Sharas Siltstone Member and the overlying Khalaqah Shale Member.
Mohamed Gamiel El-Behiry
Seismic refraction survey is carried out to evaluate the proposed site of the New-Fayoum City, southwest of Cairo, for constructions. The interpretation of the collected seismic data yields two-dimensional seismic models composed of three main seismic layers; a surface layer of wadi-fill dry clastics and calcareous fragments covering an intermediate layer of sandy calcareous mudstone overlying a bedrock of highly argillaceous calcareous mudstone. The large spectrum of the bedrock seismic velocity at the proposed site is attributed to the difference in the bedrock mechanical and physical parameters. A bedrock seismic velocity contour map for the proposed site reveals three main seismic zones; the first zone, occupies the south-eastern part of the site and is characterized by low seismic velocity (2000 m/s) and is considered as non-eligible for constructions; the second zone, occupying the western and southern parts of the site, is characterized by intermediate seismic velocity (2000-2500 m/s) and is considered less-eligible for constructions; and the third zone, located mainly at the northern part of the site, is characterized by high seismic velocity (>2500 mls) and considered the most eligible part of the proposed site for constructions
Mohammed Abu-Qudais, Abdel-Aziz Ebied, and Ghassan Mousa
Spark-ignition engine exhaust gases contain oxides of nitrogen (NO.), carbon monoxide (CO), and organic compounds that are unburned or partially burned hydrocarbons (HC). These exhaust emissions are presently subject to regulatory control. Of these harmful pollutants, NO. emissions are the hardest to control under the current status of emission control technology. The present paper deals with the use of the exhaust gas recirculation (EGR) for NO. control. The NO. concentration in the exhaust was studied experimentally, and theoretically using the method of element potential over a wide range of fuel-air ratios, percentage of exhaust gas recycled, and engine speeds. Comparison of the measured and calculated exhaust nitric oxide concentration shows good agreement overall operating conditions. To make the EGR method effective over a wide range of operating conditions, two EGR maps were constructed. They can be used as input data to a closed loop control system, to regulate the EGR rate required to reduce the NO. emission to the reduction target.
Ibrahim Saker Al-Mssallem and Muneera Qasim Al-Mssallem
SDS-Polyacrylamide gel electrophoresis of glutelin fraction reveals that dry grains of American, Basmati and Al-Hassawi rice varieties tested have the same pattern of the major polypeptides of 14, 15-18, 26-31 and 45-51 KD. However, three major polypeptides vary in their degree of expression. These cultivars vary in the number of minor high molecular weight polypeptides . American and Basmati rice have a 75 KD polypeptide which is not expressed in Al-Hassawi rice varieties. However, Al-Hassawi rice varieties have a polypeptide with a MW of 59 KD which is not expressed in American and Basmati rice.
Mohammed A. Al-Abdulsalam
A two-year field experiment was initiated on loamy sand soil in 1992-1993 and 1993-1994 to study the effect of synthetic nitrogen fertilizer and residual effect of organic manure on growth, yield and yield components of wheat cv. Yecora rojo. Nitrogen fertilization increased both yield and plant height. Yields increased from 1.34 to 5.54 ton ha-1 by increasing N from 0 to 200 Kg ha-1. The increase in yield was attributed to increased number of spikes m-2, number of grains spike-1 and 1000-grain weight. Yields were also increased from 3.20 to 3.66 ton ha-1 by increasing organic manure from 0 to 50 ton ha-1. Plant height and flag leaf area increased from 8.43 to 72.16 cm and from 10.23 to 23.64 cm2 due to increasing N level from 0 to 200 Kg ha- 1. Plants receiving 200 kg N ha-1 with 50 ton ha-1 organic manure produced plants with more spikes, number of grains, biological yield, grain and straw yield. However, the crop index was higher in plots receiving 200 Kg N ha-1 without organic manure residues. The rate of increase for plant height, number of spikes m-2, number of grains spike-1, biological yield and grain and straw yield was higher under low than high nitrogen application rates.
A. A. El-Khatib
The application of Two Way Indicator Species Analysis (TWINSPAN) classified the island into four different habitat types. Each of them comprises different communities with indicator species of their own.
Deterended Canonical Correspondence Analysis (DCCA) was used to study species-environment relationships. Accordingly. the most important environmental factors affecting the distribution and structure of the present communities are: moisture content. depth of water. CaC03 concentration. organic carbon and soil texture.
The former vegetation of the island was studied through palynological technique. DCA (Deterended Correspondence Analysis) ordination of TWINSPAN pollen assemblage groups clarified the distribution of hydrophytes in the lowermost layer and mesophytes in the uppermost layer of profile dug (60 cm depth) in the island. Amphibious species occupied the middle level reflecting a change from hydric to mesic conditions.
H. Elhag, Essam Abdel-Sattar, M.M. El-Domiaty, M.M. El-Olemyl and J.S. Mossa
Artemisia annua plants were selected from seed-grown plants in the season 1990/1991 according to the morphological characters previously identified as markers for high artemisinin production. These were micropropagated by in vitro techniques as previously described. The performance of these micropropagated clones and those of the seasons 1989-1991 was followed up after transfer to the field for two seasons. They were compared to the mother plants in terms of morphological characters and their content of artemisinin and related sesquiterpenes, as determined by reversed-phase HPLC. It was found that the identified morphological characters are suitable for selection of high artemisinin-producing clones of A. annua. Several micropropagated clones with relatively high contents of artemisinin and/or artemisinic acid are reported. The optimum time for the transfer of the micropropagated plants to the field in Riyadh was identified to be late October to early November. One to two years of maintenance in culture during micropropagation was consistent with the preservation of the plant's characters and sesquiterpenes contents. The parasite, Orobanche cernua Loefl. was identified as a root parasite of A annua that may cause heavy losses in the biomass yield.
A.A. Salamah and A.S. Al-Ibaidi
Iron-free lactoferrin or iron-free transferrin inhibited the growth did not affect the viability of Yersinia pseudotuberculosis cells that were present in iron-complete BHI broth or in BHI broth iron-depleted by MgCO₃. This type of inhibition was reversed by the addition of iron-saturated lactoferrin or iron-saturated transferrin, which appeared to be capable of serving as a source of iron in the above iron-depleted medium, or by transfer to iron-complete BHI broth. In contrast, there was a rapid loss of viability for those cells which were suspended in deionized water and were treated by iron-free lactoferrin or iron-free transferrin. The iron-irreversible inhibition which was observed in the absence of medium suggests that both lactoferrin and transferrin have a direct bactericidal effect on Y. pseudotuberculosis that cannot be attributed to simple iron-deprivation.