Al-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601RECOVERY OF ZINC AND RARE EARTHS FROM ABU RUSHIED FERRUGINOUS ORE MATERIAL, SOUTH EASTERN DESERT, EGYPT75851087010.21608/absb.2007.10870ENN. T.EL-HAZEKNuclear Materials Authority, P.O. Box: 530 El-Maadi, Cairo, EgyptT. E.AMERNuclear Materials Authority, P.O. Box: 530 El-Maadi, Cairo, EgyptM. H.BADREl-Azhar University, Faculty of Science (Girls), Chemistry Department.N. M.SHAWKYEl-Azhar University, Faculty of Science (Girls), Chemistry Department.D. I.ZAKYNuclear Materials Authority, P.O. Box: 530 El-Maadi, Cairo, EgyptJournal Article20070701This paper is concerned with the recovery of separate Zn and REEs pure concentrates from a sulphate leach liquor of Abu Rushied ferruginous ore material. Preparation of separate Zn/REEs concentrates was carried out by either selective oxalate precipitation of the REEs or else by bulk hydroxides precipitation followed by re-dissolution of Zn as zincate. The leached REE values could also be recovered in two main steps namely; precipitation of LREEs as their double sulphate during or directly after the acid leaching while the potentiality of individual separation of the HREEs concentrate left behind was studied through the displacement technique using the cationic exchange resin Dowex 50W-X8. A tentative flowsheet for the overall treatment of Abu Rushied ore material is also presented.https://absb.journals.ekb.eg/article_10870_5f746191c2bd1d18da3f7ea56a98c640.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601NEW SYNTHESIS OF 1,4-DIARYLPIPERAZINE-2,5-DIONE AND 3,4,5-TRISUBSTITUTEDPYRIDINE-2(1H)-ONE1511611087110.21608/absb.2007.10871ENFATHI A.ABU-SHANABChemistry Department, Faculty of Science, Al-Azhar University, Assiut 71524,Journal Article20070702Treatment of <em>N</em>-aryl 2-chloroacetamides (<strong>2a-f</strong>) with sodium isopropoxide in isopropyl alcohol afforded 1,4-diarylppiperazine-2,5-dione (<strong>3a-f</strong>). Treatment of malononitrile dimer (<strong>9</strong>), ethyl cyanoacetate (<strong>11</strong>) and the arylidines of cyanothioacetamide (<strong>13</strong>) with DMFDMA afforded the corresponding enamines (<strong>10, 12 and 14</strong>) respectively. Reaction of <strong>14</strong> with either sodium ethoxide or sodium methoxide affords 5-cyano-4-ethoxy-6-oxo-1,6-dihydro-pyridine-3-carboxylic acid amide (<strong>15</strong>) and 5-cyano-4-methoxy-6-oxo-1,6-dihydro-pyridine-3-carboxylic acid amide (<strong>16</strong>) respectively.https://absb.journals.ekb.eg/article_10871_70e46bf74778a7eaf710a3cef785499d.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601SOME REACTIONS OF 6,8-DIBROMO-2-PROPENYL-4H-3,1-BENZOXAZIN-4-ONE WITH NITROGEN NUCLEOPHILES UNDER MICROWAVE IRRADIATION1631711087310.21608/absb.2007.10873ENA. A.ABDALHAChemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo, EgyptM. K.ABOU EL-REGALChemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo, EgyptM. A.EL-KASSABYChemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo, EgyptA. M.NAZEERChemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo, EgyptJournal Article20070815The benzoxazinone derivative <strong>(1)</strong> was prepared upon the action of crotonoyl chloride on 3,5-dibromoanthranilic acid in pyridine. Microwave irradiation assisted the aminolysis of <strong>(1)</strong> with nitrogen nucleophiles as benzyl amine, hydrazine hydrate and formamide to give the amide derivatives <strong>(2a-c)</strong> respectively. Quinazolinone derivatives <strong>(3a-e)</strong> were produced upon the action of primary amines such as m-nitroaniline, p-toluidine, p-anisidine, benzyl amine and/or hydrazine hydrate respectively on the benzoxazinone derivative <strong>(1)</strong>. An excess amount of p-anisidine, phenylhydrazine and/or p-toluidine afforded the amide and quinazolinone derivatives <strong>(4a & 5a)</strong>, <strong>(4b & 5b)</strong> and/or <strong>(5c)</strong> respectively. The benzoxazinone derivative <strong>(1)</strong> was subjected to react with secondary amines as piperidine or morpholine giving the amide derivatives <strong>(6a)</strong> or <strong>(6b)</strong> respectively under 1 : 1 molar ratio, while under 1 : 2 molar ratio, the dipiperidiyl or dimorphonyl derivatives <strong>(7a)</strong> or <strong>(7b)</strong> were formed respectively. Ammonolysis of <strong>(1)</strong> using ammonium acetate, yielded the quinazolinone derivative <strong>(8)</strong>.https://absb.journals.ekb.eg/article_10873_51350641bc724bc5fbeb700c44acc04b.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601HETEROAROMATIZATION WITH SULPHONAMIDO PHENYL ETHANONE: PART (III)*. SYNTHESIS, REACTIONS AND BIOLOGICAL ACTIVITY OF ENAMINONE CONJUGATED WITH DIMETHYLAMINOSULFONYL MOIETY1731871088010.21608/absb.2007.10880ENMAHMOUD M.ABDEL AALChemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt.AHMED A.EL-MAGHRABYChemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt.SABER M.HASSANChemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt.MAHMOUD S.BASHANDYChemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt.Journal Article200702014-(3-Dimethylaminoacryloyl)-N,N-dimethylbenzenesulfonamide <strong>(2)</strong> was prepared and used as key intermediate in the synthesis of the title compounds, the structure of these compounds were elucidated on the bases of elemental analysis, IR, <sup>1</sup>H-NMR and mass spectra. The Antimicrobial and Antifungal activities of the prepared compounds are also reported. https://absb.journals.ekb.eg/article_10880_723aaf5f44a08a3a412c5493d686acaa.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601EFFECT OF INORGANIC ACID SOLUTIONS ON ELECTROCHEMICAL BEHAVIOR OF TIN ELECTRODE1892051088110.21608/absb.2007.10881ENR. M.ABOU SHAHBAChemistry Department, Faculty of science (for girls), AL- Azhar University, Nasr City, Cairo, EgyptA. S.AHMEDChemistry Department, Faculty of science (for girls), AL- Azhar University, Nasr City, Cairo, EgyptE. VATTIAChemistry Department, Faculty of science (for girls), AL- Azhar University, Nasr City, Cairo, EgyptA. E.EL-SHENNAWYChemistry Department, Faculty of science (for girls), AL- Azhar University, Nasr City, Cairo, EgyptJournal Article20070201The electrochemical behavior of tin metal was studied in some inorganic acid solutions; HCl, HNO<sub>3</sub>, H<sub>2</sub>SO<sub>4</sub> and H<sub>3</sub>PO<sub>4</sub>, using the open circuit potential measurements and the potentiodynamic polarization technique. In addition, the metallographic structure of tin electrode was examined before and after immersion in test solution by using scanning electron microscope (SEM). The identification of the elements presented in the surface of specimen after immersion in different solutions was performed using an energy dispersion X-ray analysis(EDAX). The obtained results demonstrated that the aqueous dilution of HCl, H<sub>2</sub>SO<sub>4</sub> and H<sub>3</sub>PO<sub>4</sub> retarded the corrosion of tin electrode, (hydroxyl ion plays a part in basic salt formation), while dilution of HNO<sub>3</sub> acid accelerated the corrosion. It is evident from SEM image that, there were grain boundaries and the surface was more active and rougher in case of mechanically polished electrode. In non-polished electrode, the surface was covered with a protective layer; generally SnO<sub>2</sub>. In potentiodynamic polarization study, the formation of basic salt Sn(OH)Cl was preference to any other oxide in HCl solutions. The increase in NO<sub>2</sub> concentration was responsible for the increase in the rate of dissolution in HNO<sub>3</sub>. The tin dissolution in sulphuric acid occurred through an intermediate of (SnHSO<sub>4</sub>OH) species. https://absb.journals.ekb.eg/article_10881_497e062b9bda782ef69899addd981d7f.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601A NEW APPROACH FOR GRAFT COPOLYMERIZATION OF JUTE2072211088210.21608/absb.2007.10882ENE.El-ALFYTextile Research Division, National Research Center, Dokki, Cairo, EgyptN. E.ZAMZAMTextile Research Division, National Research Center, Dokki, Cairo, EgyptM.FIKRYTextile Research Division, National Research Center, Dokki, Cairo, EgyptM. A.YOUSEFFaculty of Science, Helwan UniversityA.ABOU-OKEILTextile Research Division, National Research Center, Dokki, Cairo, EgyptJournal Article20070102The graft copolymerization of glycidyl methacrylate (GMA) on jute fibers at ambient conditions is the desired goal. Graft copolymerization of (GMA) on jute fibers was carried out using Ammonium Persulphate Acetone Sodium Bisulphite (APS/ASBS) initiating redox system. The grafting reaction was studied with respect to graft yield (GY), grafting efficiency (GE) and total conversion (TC). Factors such as pH value, liquor ratio (L: R), redox initiator concentration, addition sequence, reaction time, temperature and GMA concentration [M], were investigated. The results obtained showed that the optimal grafting yield is obtained at the following conditions: initiator concentration of 20/40 mmole/l for APS/ASBS respectively, liquor ratio(I:20), pH value 3, time 120 min., temperature 20°C, and monomer concentration [M] 150% based on weight of substrate (OWS). Grafted and scoured jute fibers were characterized via thermal gravimetric analysis (TGA) and infra red spectroscopic analysis (IR).https://absb.journals.ekb.eg/article_10882_2608e812c5c1396386f46ee0453f6c0b.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601ELECTROCHEMICAL AND DENSITOMETRIC DETERMINATION OF ZOLMITRIPTAN IN PHARMACEUTICAL DOSAGE FORMS2232361109810.21608/absb.2007.11098ENA. A.WASSELNational Organization for Drug Control and ResearchL. I.BEBAWYNational Organization for Drug Control and ResearchM. A.EL.RIESNational Organization for Drug Control and ResearchJournal Article20070903Two methods for the determination of antimigrain drug zolmitriptan in bulk powder and in pharmaceutical dosage forms by voltammetric and densitometric methods are developed. Voltammetric method depends on the oxidation of zolmitriptan on an activated carbon paste electrode. The compound is oxidized irreversibly at high positive potential. The response was evaluated with respect to pH; scan rate, nature of the buffer and other variables. The peak current at about 0.76V, with the maximum current at pH 5 ±0.2 acetate buffer. The mechanism of the reaction is controlled by oxidation of the N-H group in the indole ring. By differential pulse voltammetry, the calibration plot was linear in the range 3.99 x10<sup>-7</sup> – 2.90 x10<sup>-6 M.</sup>
The second method is based on the application of thin layer chromatographic separation of the studied drug in the presence of its degradation product followed by the densitometric measurements of the spot areas of the drug. After separation on silica gel GF<sub>254</sub> plates using methanol: ammonia 25% (100:1.5 v/v) as mobile phase, the chromatographic zones corresponding to the spots of zolmitriptan were scanned at 285nm. The calibration function was established in the range of 1.00- 9.00 µg/ spot. The suggested methods were used to determine the cited drug in bulk powder, and pharmaceutical dosage forms. Results were compared statistically with the reported method.https://absb.journals.ekb.eg/article_11098_12e5d8aae3c0eb4cf2ad2f781fd26826.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601PRINTING OF DIRECT DYE ON SILK FABRIC WITH IMPROVED DYE FIXATION AND WET –FASTNESS171109910.21608/absb.2007.11099ENWAGIHABDALLAHTextile printing, Dyeing and Finishing Department, Faculty of Applied Arts, Helwan University, Cairo, Egypt.ABEERFATH ALLATextile printing, Dyeing and Finishing Department, Faculty of Applied Arts, Helwan University, Cairo, Egypt.Journal Article20070917Application of direct dyes on silk fabric suffer from problems of poor fastness properties as well as decrease in dye fixation .A formaldehyde donor agent, i.e. Hexamine, (hexamethylene tetramine), was used for improving dye fixation and wet fastness when added to the printing paste during printing silk fabric with a direct dye containing free amino groups (Diamine Supra Blue GRL200% ).
https://absb.journals.ekb.eg/article_11099_a0db1a72284a621f185c8a9322cf2865.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601INHIBITION EFFECT OF SOME POLYETHYLENE GLYCOLS (PEG) ON THE CORROSION OF ALUMINUM IN 1.0 M PHOSPHORIC ACID9191110010.21608/absb.2007.11100ENS. A.SOLIMANChemistry Department, Faculty of Science, Al-Azhar University, Cairo, EgyptJournal Article20070802The effect of some polyethylene glycols (PEG) as inhibitors on the corrosion of aluminum in 1.0 M H<sub>3</sub>PO<sub>4</sub> has been studied using weight loss and polarization measurements in various concentrations of PEG and at different temperatures. The dissolution of aluminum in phosphoric acids increases by increasing temperatures and decreases by increasing the additive concentrations. The inhibition efficienciy values proceed according to the following order of the molecular weights of the used inhibitors PEG 4000 > PEG 2000 > PEG 1500 > PEG 400. For relatively higher molecular weights inhibitor (beginning from 1500) the type of adsorption taking place at the surface of aluminum was physical adsorption whereas for the molecular weight. = 400 had different behavior till 50<sup>o</sup>C and then the inhibition efficiency decreasing at 60<sup>o</sup>C indicating physical adsorptions. The lone pair of electrons of oxygen atom of hydroxyl groups play an important role in the adsorptions of additives on aluminum surface, which affected by polarization. The thermodynamic calculated values of activation and adsorption were calculated and discussed.https://absb.journals.ekb.eg/article_11100_c43dc7958a95982f9a109327fdb42834.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601STUDIES OF THE EFFECT OF VOLATILE COMPOUNDS IN ATMOSPHERE OF GREATER CAIRO AREA21351110110.21608/absb.2007.11101ENM. M.EMARAChemistry Dept. Faculty of Science, Al-Azhar University, Cairo, Egypt.S. A.SOLIMANChemistry Dept. Faculty of Science, Al-Azhar University, Cairo, EgyptA. A.RAMADANEgyptian Atomic Energy Authority, Cairo, Egypt.H. A.EL-KORDYBadr El-Deen Petroleum Company, Cairo, EgyptJournal Article20070801Volatile organic compounds (VOCs) have been determined to be human risk factor in urban environments, as well as primary contributors to the formation of photochemical oxidants. Concentrations of VOCs were measured at five monitoring sites located in the greater Cairo area, Egypt, as a part of the air pollution study. On each sampling day, 22 abundant VOCs were collected three times per day (7-9 in the morning, 2-4 afternoon and 8-10 evening) during the period from March 2003 to March 2004, to observe diurnal variations of volatile organic compounds on the air of Greater Cairo area and air quality information system in Egypt. Most of the VOCs species showed diurnal variations with higher concentrations during the morning and evening, and lower concentrations during the afternoon. However, in the afternoon , the concentrations of aromatic compounds, closely correlated with solvent usage such as toluene, ethyl benzene, m-/p- xylene, and o-xylene, were slightly higher than or comparable to those in the morning. This may be due to the increase of evaporative emissions derived from the rise in ambient temperature and additional sources such as the use of solvents in petrol, painting, printing and dry cleaning.https://absb.journals.ekb.eg/article_11101_332901866fd6e73a7e0b57d62774df02.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601MINIMIZING THE CHLORINATION BY-PRODUCTS BY OPTIMIZING THE CHLORINE DOSE AND TEMPERATURE37501110210.21608/absb.2007.11102ENJournal Article20070801Disinfection<br />of water by chlorine produces a number of halogenated disinfection by-products<br />(DBPs). Trihalomethanes (THMs) and haloacetic acids (HAAs) are the domin0ant<br />species found in finished drinking water. Several toxicological studies shown<br />some disinfection by-products (DBPs), including certain (THMs) and (HAAs), to<br />be carcinogenic in laboratory animals. Due to all these potential problems<br />associated with the formation of disinfection by-products (DBPs) during the<br />free chlorination of drinking water have been well documented and due to the<br />health risks associated with them, the US Environmental Protection Agency<br />(USEPA) began regulating the levels of these disinfection by-products (DBPs) in<br />finished drinking water in 1979. Many<br />researchers suggested different procedures in order to minimize the<br />concentrations of the formed DBPs. These procedures based upon the decreasing<br />of the natural organic matter (NOM) in the raw water e.g. ultrafiltration<br />(UF)–nanofiltration (NF) combined membrane process which showed better removal<br />efficiency of NOM. Another studies suggested usage of another disinfectants<br />e.g. ozone. This study aimed to minimize<br />the concentrations of the (DBPs) via the optimization of the added chlorine<br />dose which complies with the microbiological requirements. Also the effect of<br />temperature on the formed DBPs was studied. The results showed that the<br />concentrations of the various (DBPs) are inversely proportional with the<br />temperature. Also this study suggested another procedure to calculate the most<br />suitable chlorine dose.https://absb.journals.ekb.eg/article_11102_484215a4f2adbea327c830918b39bded.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601MONITORING AND INVESTIGATION OF THE CONCENTRATION LEVELS OF THE REGULATED FIVE HALOACETIC ACIDS AND DALAPON IN THE DRINKING WATER AND DURING THE TREATMENT STAGES51611110310.21608/absb.2007.11103ENJournal Article20070801https://absb.journals.ekb.eg/article_11103_f9de87412d30e4aa3349d177ef466636.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070619CHARACTERISTICS AND LEACHABILITY OF ZINC AND RARE EARTHS FROM ABU RUSHIED ORE MATERIAL, SOUTH EASTERN DESERT, EGYPT63741110410.21608/absb.2007.11104ENJournal Article20070903A rare earth (REEs) and Zn ore martial belonging to a poly-metallic mineralization of Abu Rushied area, Southern Eastern Desert of Egypt is subjected to mineralogical analysis and acid leaching. The former proved that both Zn (assaying 5%) and REEs (assaying 3.1%) are found adsorbed upon the iron oxide mineral goethite (equivalent to 15 % Fe<sub>2</sub>O<sub>3</sub>). Acid leaching studies using sulphuric acid defined the optimum conditions for dissolving about 94% of Zn and 92.5% of REEs. Besides being a powerful oxidizing agent and can create chloric acid, NaClO<sub>3 </sub>was incorporated in the leaching process to decrease the required input sulphuric acid. In addition, NaClO<sub>3</sub> adequate Na<sub>2</sub>SO<sub>4</sub> that could be used in the early precipitation of the (light REEs)LREEs as their double sulphates. https://absb.journals.ekb.eg/article_11104_5a657d3e1702667c4b9bd0de9561fe91.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601PREPARATION CONDITIONS OF HUMIC ACIDS FROM VILLAGE'S COMPOST FUEL (VCF) AND THEIR EFFECTS ON HUMIC ACIDS CHEMICAL CHARACTERISTIC ALTERNATION DURING ISOLATION PART II. EFFECT OF THE EXTRACTION CONDITIONS ON THE FUNCTIONAL GROUPS CONTENTS OF HUMIC ACIDS AS REVEALED BY SPECTROSCOPIC ANALYSIS871011110510.21608/absb.2007.11105ENM. H.BADRChemistry Department, Faculty of Science, Al-Azhar University (For Girls)Journal Article20070116IR spectra of humic acids ( HAs) extracted by NaOH solution under different conditions showed that HAs extracted by 0.1 M after 6h and 16 h have identical finger print regions. These spectra indicate the presence of highest number of functional groups and highest aromatic COOH group content, in comparison with ( HAs) extracted by 0.1M after 2h and 24 h. IR spectrum of humic acids HAs extracted by 0.2M after 2h was generally similar with the two latter spectra. The IR spectra of HAs extracted after 2h by 0.5M, 1M, and 2M not only show the disappearance of aromatic COOH bands but also indicate the hydrolysis of ester moieties and increase the OH groups content of the extracted HAs. The IR spectra of HAs extracted at the latter three concentrations showed attacked finger print regions. Uv-Vis spectra show two clearly observable peaks at 208 and 280 nm which are characteristic to these humic acids. The spectral change of the latter are in agreement with the results obtained by IR analysis According to results obtained, the extraction by 0.1M NaOH after 16h leads to production of HAs of highest condensation, highest functional group content. https://absb.journals.ekb.eg/article_11105_438c59c131c4f61aab0ba4cf1cf593e8.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601SYNTHESIS OF SOME NEW BENZOFURAN DERIVATIVES OF EXPECTED BIOLOGICAL ACTIVITY1031141110610.21608/absb.2007.11106ENS. A.HESSEINChemistry Department, Faculty of Science (Girl’s), Al-Azhar University, Cairo, EgyptJournal Article20070104Treatment of 1-[6-hydroxy-4-methoxybenzofuran-5-yl]ethanone <strong>(1)</strong> with cinnamaldehyde gave 1-[6-hydroxy-4-methoxybenzofuran-5-yl]-5-phenylpenta-2,4-diene-1-one <strong>(2)</strong> which reacted with formaline and 4-chloroniline to give benzofuran derivative <strong>(3)</strong> according to Mannich reaction. Interaction of <strong>2</strong> with 20% of sulphuric acid, malononitrile, ethylcyano acetate, phenyl hydrazine and guanidine hydrochloride afforded the corresponding furo[3,2-g]chromon-5-one <strong>(4),</strong> pyridine, pyrazole and pyrimidine derivatives <strong> (5-8)</strong>. Also, compound <strong>8</strong> reacted with phosphorus-oxychloride in dimethyl formamide and p-flurobenzylidenemalononitrile to give formyl and pyrimidopyrimidene derivatives (<strong>10, 12</strong>).https://absb.journals.ekb.eg/article_11106_176870003d2e876a0c9418fc19ae09ea.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601EFFECT OF FLY-ASH AND SILICA FUME ON THE PROPERTIES OF CONCRETE EXPOSED TO HIGH TEMPERATURE1151321110710.21608/absb.2007.11107ENJournal Article20180814The development of high concrete temperatures could cause a number of effects that have been shown to be determined to long-term concrete performance. High concrete temperatures increase the rate of hydration, thermal stresses, the tendency for drying shrinkage cracking, permeability, and decrease of long-term concrete strengths and durability as a result of cracking. The objective of this study is to investigate the effects of using fly ash and silica fume on the strength and absorption of cement concrete and pozzolanic cement concrete in hot condition. The cement concrete and pozzolanic cement concrete specimens containing fly-ash or silica fume were first cured in water for different periods 1, 3, 7, 28, 90 and 180 days then exposed to high temperature 45<sup>o</sup>C ( maximum summer temperature in Egypt and Arabian Gulf countries) in oven for 2,8,12 and 24 hours. The effect of fly-ash and silica fume contents on the absorption capacity of concrete specimens was evaluated by measuring 48-hours absorption and volume of permeable voids. The specimens were also tested for compressive strength and moisture content. The results show an increase in the compressive strength and decrease in moisture content of cement concrete and pozzolanic cement concrete specimens with increasing both curing exposing temperature time. The absorption of these concretes decreased with time of curing and increased with exposing temperature time .The absorption of both fly-ash and silica fume cement concrete specimens decreased significantly at early stages (3-7days) of curing. While the absorption of cement concrete specimens were effected significantly by exposing temperature period, no significant change in the absorption of pozzolanic cement concretes due to increasing exposing temperature period was observed, especially after 7 days of curing. The volume of permeable voids also decreased with curing. The highest reduction in the absorption and volume of voids was observed in the fly-ash concrete specimens.https://absb.journals.ekb.eg/article_11107_69b6f6770ead39d740eef9b45eef4859.pdfAl-Azhar University, Faculty of Science (Boys)Al-Azhar Bulletin of Science1110-253518Issue 1-A20070601THE INHIBITION EFFECT OF SOME PYRIMIDINE DERIVATIVES ON CORROSION OF ALUMINUM AND SOME OF ITS ALLOYS IN 2.0 M HCl SOLUTIONS1331491110810.21608/absb.2007.11108ENS. S.MAHMOUDChemistry Department, University College of Girls for Arts, Science and Education, Ain Shams University, Heliopolis, Cairo, EgyptM. M.AHMEDChemistry Department, University College of Girls for Arts, Science and Education, Ain Shams University, Heliopolis, Cairo, EgyptJournal Article20070106In the present study the corrosion of aluminum and some of its alloys in 2M HCl was studied. The effect of some pyrimidine derivatives, as organic inhibitors, on the corrosion of aluminum and its alloys in HCl solution was studied. The techniques used of measurements were: (i) linear polarization (ii) galvanostatic polarization and (iii) electrochemical impedance spectroscopy. The corrosion rate of the investigated electrodes was found to be depended on the type and composition of the metal electrode. The pyrimidine derivatives acted as mixed inhibitors in acidic media.
It was found that the inhibition efficiency of the inhibitor greatly depended on the type, size, and concentration of the compound and on the electron density of the adsorption centers. The inhibitory effect of the investigated compounds resulted from their adsorption on the metallic surface via adsorption centers and /or electrostatic interaction between the organic compound and electrode. The adsorption of inhibitors on the metallic surface from 2.0 M HCl solutions obeyed the Temkin’s adsorption isotherm. Results obtained from linear polarization, galvanstatic polarization and impedance measurements are in a good agreement.https://absb.journals.ekb.eg/article_11108_49124feaaa7d95112bd7676ee10b1d5c.pdf