311 research outputs found

    Studies on Plant Cover of Wadi Umm El-Rakham in The Northwestern Coast of Egypt

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    The present investigation was carried out to study the phytosociological characteristics of the range land in Wadi Umm El-Rakham, in Northwestern coast of Egypt during spring 2004 - fall 2005. Thirty eight plant species belong to 17 families were found in Wadi Umm El-Rakham. Eighteen species were annuals and 20 species were perennials. A total of 18 species were palatable, the rest were not. Among annulus, 11 species were palatable, whereas among perennials seven species only were palatable. Fresh and dry foliage yield, species density, frequency, herbage cover and the importance value as well as their relative values were determined in the different locations in the wadi (i.e. top, ridge and wadi bed).  All these traits recorded their highest value in the wadi bed location during spring season of both years 2004 and 2005. Meanwhile, the lowest values of all these traits were recorded in the wadi top location. Significant interaction was noticed among the studied factors i.e. year, location and season) in wadi bed location during spring season of both years.      ÂÂ

    Behaviour of 4-(4-acetoaminophenyl)-4-oxobut-2-enoic acid towards carbon and nitrogen nucleophiles and use of these products in the synthesis of some interesting heterocycles

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    The present work is devoted to study the interaction of-aroylacrylic acid derivative (1) with some containing active methylene compounds under Michael reaction conditions and afforded the Michael adducts (2a-e). When compound 1 was allowed to react with cyclohexanone in the presence of ammonium acetate as catalyst, it afforded hydroquinoline derivative (3). Interaction of the acid 1 with highly and moderately reactive hydrocarbons e.g. p-xylene and acetanilide in the presence of anhydrous aluminumchloride under Friedel-Crafts reaction conditions afforded (4a-b). On the other hand, when the acid 1 was allowed to react with benzyl amine in dry benzene yielded 2-benzylamino-4-(4-acetaminophenyl)-4-oxobutanoic acid (5). This later compound was used to synthesize some heterocyclic compounds (7-11). Also, aza Michael adduct (6) used asthe key starting material for the synthesis of some interesting heterocyclic compounds e.g. pyridazinone, oxazinoneand furanone derivatives (13-16)

    Some Chemical Aspects of Tetrahydro-1-thiopyran-4-one Derivatives

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    3,5-Diarylmethylene-2,6-diphenyltetrahydrothiopyran-4-thiones, 2, reacted with two or four moles of bromine to form 3-aryimethylene 5-bromoarylmethylene- 2,6-dipheny1tetrahydrothiopyran- -4-thione, 3, and 3-arylmethylene-5-bromoarylmethylene-2,6-dibromo- 2,6-diphenyltetrahydrothiopyran-4-thione, 5, respectively. Compound 2a reacted with amines giving 2,6-diphenyl-5-iminophenylmethyl- 3-phenylmethylenetetrahydrothiopyran-4-thiones, 6. Diphenydiazomethane and 9-diazofluorene converted 2a into 4-diphenylethylene- 2,6-dipheny1-3,5 diphenylmethylenetetrahydrothiopyran, 7, and 2,6-diphenyl-3,5-diphenylmethylene-4-(9-fluorenylidene) tetrahydrothiopyran, 8, respectively. Compounds 2 with copper-bronze afforded 3,3\u27,5,5\u27-tetraarylmethylene-2,2\u27 ,6,6\u27-tetraphenyl-Lr-thio- 4,4\u27 dipyranylidenes

    Utility of 4-(4-acetoaminophenyl)-4-oxo-but-2-enoic acid to prepare Pyranand Pyridine derivatives as building blocks in Heterocyclic Synthesis

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    The present work is devoted to study the interaction of β -aroylacrylic acid derivative (1) with malononitrile in the presence of piperidine and/or ammonium acetate, then using the formed compounds as a starting material for synthesizing fused and isolated heterocyclic system. Ithas been established that the β-aroylacrylic acid (1) reactwith malononitrile in (DMF) in the presence of piperidineas catalyst with formation of 4H-pyran derivative (2). Bychanging the catalyst into ammonium acetate, pyridine derivative (3) has been obtained. When compound (2) wasallowed to react with triethylorthoformate afforded ethoxymethyleneamino-4H-pyran (4). Compound (4) was used askey starting material for synthesizing some interesting annulated and heterocyclic systems (5-8). Also, the maleamic acid derivatives (9) and (15) have been synthesized via the interaction of (2) and (3) with maleic anhydride to study the behavior of the formed maleamic acid derivatives asanalogies of β-aroylacrylic towards different active methylene compounds under Michael addition reaction (10-14); (16-18)

    Ion Flotation of Copper(II) and Lead(II) from Environmental Water Samples

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    The present study aims to develop a simple, rapid and economic procedure for copper(II) and lead(II) removal under the optimum conditions investigated. It is based on the complex formation between Cu2+ and Pb2+ ions and diphenylcarbazone (HDPC) followed by flotation with oleic acid (HOL) surfactant. The different parameters (namely: solution pH, HDPC, HOL, copper and lead concentrations, ionic strength, temperature and the presence of foreign ions) influencing the flotation process were examined. Nearly, 100% of Cu2+ and Pb2+ ions were removed from aqueous solutions at pHs 6 and 7, respectively at room temperature (~25 \ub0C). The procedure was successfully applied to recover almost copper(II) and lead(II) spiked to some natural water samples. Due to the rapid, simple and economic nature of the procedure, a flotation mechanism is suggested for metal removal in wastewater systems

    Amenability of heap leaching technology on uranium extraction from Gattar and El Missikat area, Eastern Desert, Egypt: A kinetic approach

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    Studies of uranium heap leaching from different uranium mineralization situated in Eastern Desert of Egypt was investigated via batch experiments, followed by its optimum condition applicationon column percolationtests.The optimum process operating parameters were implemented on large column scale in order to make more condition control and evaluate the time and reagents needed in the large scale. The results show thatleaching efficiency of GIIattained about 78.3% with 34kg/ton acid consumption in a 44 days period, while leaching efficiency of El-Missikat attained about 86.6% with 28kg/ton acid consumption in a 40 days period.Kinetics reaction models of column tests have been investigated to optimize the column leaching behavior. Based on the leaching results of two mineralized samples, the rate of the uranium metal dissolution is controlled by the chemical reaction and the diffusion reaction but diffusion reaction control was more predominate than a chemical reaction control

    A critical appraisal of molecular xenomonitoring as a tool for assessing progress toward elimination of lymphatic filariasis

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    We used molecular xenomonitoring (MX, detection of filarial DNA in mosquitoes) to evaluate the impact of mass drug administration (MDA) in sentinel locations in Egypt with high (11.5%) and low (4.1%) baseline microfilaria prevalence rates. Blood-fed Culex pipiens were pooled by household and tested for Wuchereria bancrofti DNA by PCR. There was no significant relationship between the infection status of household residents and parasite DNA status of mosquitoes from the same houses. After 5 MDA rounds, parasite DNA rates in mosquitoes in high- and low-prevalence areas were reduced by 93.8% and 100% to 0.19% (95% CI: 0.076–0.382%) and 0% (95% CI: 0–0.045%), respectively. These changes were consistent with decreases in microfilaria prevalence rates in these sites; they provide insight regarding the minimal mosquito DNA rates necessary for sustained transmission of filariasis in Egypt. We conclude that MX is a powerful tool for monitoring the impact of MDA on filariasis endemicity and transmission

    Emulating long-term weather-driven transportation earthworks deterioration models to support asset management

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    The deterioration of transport infrastructure earthworks is a global problem, with negative impacts for infrastructure resilience, becoming of increasing significance as existing infrastructure ages. Key mechanisms which affect this deterioration include seasonal pore pressure cycling driven by changing weather and climate, and the long-term dissipation of construction induced excess pore pressures. These complex processes lead to significant uncertainty in rates of deterioration and the current state of existing earthworks assets. The objective in this work was to establish a framework to emulate deterministic numerical models of slope deterioration over time using statistical (Gaussian process) emulation. A validated, physically based, deterministic modeling capability has been developed that can replicate the hydro-mechanically coupled behavior of cut and embankment slopes and their deterioration as driven by weather and climate. In parallel, a statistical (Gaussian process) emulator model was developed, and then trained with data from a deterministic modeling parametric study, using a formal experimental design approach, making use of Latin hypercube sampling. Exemplar forecasting outputs are presented to demonstrate application of the approach for use in decision-making. This information can be used in the design of new earthworks and the management of existing earthwork portfolio

    IN VITRO EVALUATION OF ENSILING AND /OR EXOGENOUS FIBROLYTIC ENZYME SUPPLEMENTATION OF DATE PRESS CAKE

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    This study was conducted to evaluate the effect of ensiling and /or exogenous fibrolytic enzyme supplementation date press cake using in vitro batch culture technique . Untreated date press cake (DPC) and ensiled DPC with exogenous fibrolytic enzymes (ZAD1 and ZAD2) and with or without adding urea compared to corn grains were in vitro evaluated using batch culture technique. DM, NDF and ADF degradation and total gas production as well as fermentation parameters of the incubated samples were determined after 24 h of fermentation. Total VFAs, proportions are not affected (P > 0.05) by any of the treatments. However, value of ammonia concentration was higher (P 0.05) with the ensiling treatments. There were no significant differences in the values of DMD and OMD between the different treatments. But, the values of NDFD and ADFD were increased (P0.05) between the corn grain and the DPC without any treatments. While, values of metabolizable protein (MP) and efficiency of microbial biomass production (EMP) were increased (p<0.05) with DPC compared to corn grains . There was no significant difference in the rumen activity when using date press cake (DPC) or corn grains. Moreover, the ensiling process did not cause a clear improvement in rumen fermentation
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