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111.
Natural radioactivity and radon exhalation rates in building materials used in Egypt 总被引:2,自引:0,他引:2
Natural and fabricated building materials commonly used in Egypt were surveyed for both natural radionuclides content and radon exhalation rate. These include raw as well as construction products. Concentration of natural radionuclides in all samples were determined by γ-ray spectroscopy with HPGe detector. For Radon exhalation rate measurements of fabricated samples, the seal can-technique has been applied using CR-39 plastic track detectors. The radiation hazard indices of the total natural radioactivity in the studied samples were estimated. The results were compared with the corresponding results of different countries and were found to be lying within the average world values. Radon exhalation rate in the studied samples varied between 197 (cement brick) and 907 mBq m−2 h−1 (blast furnace slag cement). The results of this survey suggest that, using blast furnace slag cement for pre-coating the internal walls of buildings in the Urban region of Egypt is discouraged and the replacement of clay brick by cement brick will be more healthy for the public. 相似文献
112.
Magdy A. M. Ibrahim Hamdy H. Hassan Sayed S. Abd El Rehim Mohamed A. Amin 《Journal of Solid State Electrochemistry》1999,3(7-8):380-386
The electrochemical behaviour of polycrystalline silver electrodes in Na2CO3 solutions was studied under potentiodynamic and potentiostatic conditions and complemented with X-ray diffraction analysis.
Potentiodynamic E/i anodic curves exhibit active passive transition prior to an oxygen evolution reaction. The active region involves a small
peak AI followed by a major peak AII before the passive region. Peak AI is assigned to the formation of an Ag2O layer while peak AII is due to the formation of an Ag2CO3 layer. The height of the anodic peaks increases with increasing Na2CO3 concentration, scan rate and temperature. The effect of increasing additions of NaClO4 on the electrochemical behaviour of Ag in Na2CO3 solutions was investigated. The perchlorate ions stimulate the active dissolution of Ag, presumably as a result of the formation
of soluble AgClO4 salt. In the passive region, ClO−
4 ions tend to break down the dual passive film, leading to pitting corrosion at a certain critical pitting potential. The
pitting potential decreases with ClO−
4 concentration. Potentiostatic current/time transients showed that the formation of Ag2O and Ag2CO3 layers involves a nucleation and growth mechanism under diffusion control. However, in the presence of ClO−
4 ions, the incubation time for pit initiation decreases on increasing the anodic potential step.
Received: 3 July 1998 / Accepted: 10 March 1999 相似文献
113.
Salwinder Singh Dhaliwal Vivek Sharma Arvind Kumar Shukla Janpriya Kaur Vibha Verma Prabhjot Singh Harkirat Singh Shams H. Abdel-Hafez Samy Sayed Ahmed Gaber Reham Ali Akbar Hossain 《Molecules (Basel, Switzerland)》2021,26(24)
Biofortification of pulse crops with Zn and Fe is a viable approach to combat their widespread deficiencies in humans. Lentil (Lens culinaris Medik.) is a widely consumed edible crop possessing a high level of Zn and Fe micronutrients. Thus, the present study was conducted to examine the influence of foliar application of Zn and Fe on productivity, concentration, uptake and the economics of lentil cultivation (LL 931). For this, different treatment combinations of ZnSO4·7H2O (0.5%) and FeSO4·7H2O (0.5%), along with the recommended dose of fertilizer (RDF), were applied to the lentil. The results of study reported that the combined foliar application of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at pre-flowering (S1) and pod formation (S2) stages was most effective in enhancing grain and straw yield, Zn and Fe concentration, and uptake. However, the outcome of this treatment was statistically on par with the results obtained under the treatment ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage. A single spray of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage enhanced the grain and straw yield up to 39.6% and 51.8%, respectively. Similarly, Zn and Fe concentrations showed enhancement in grain (10.9% and 20.4%, respectively) and straw (27.5% and 27.6% respectively) of the lentil. The increase in Zn and Fe uptake by grain was 54.8% and 68.0%, respectively, whereas uptake by straw was 93.6% and 93.7%, respectively. Also the benefit:cost was the highest (1.96) with application of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage. Conclusively, the combined use of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage can contribute significantly towards yield, Zn and Fe concentration, as well as uptake and the economic returns of lentil to remediate the Zn and Fe deficiency. 相似文献
114.
115.
Syntheses of the title ring systems are described starting with benzothiazol‐2‐ylacetohydrazide (1). Thus, 1 was reacted with carbon disulfide to afford the 2‐methyl heteroaryl derivative 2, which on reaction with hydrazine hydrate yielded the corresponding triazole compound 3. Also, 1 can undergo a reaction with an isothiocyanate to give the N‐thiocarbonyl adduct 4 that can then be cyclized to produce a 2‐methyl heteroaryl analog 5 or 6. Compounds 8 or 9 could be obtained by the reaction of 1 with an aryl aldehyde followed by malononitrile or via its self‐cyclization, respectively. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 177–182, 1999 相似文献
116.
In this article, a new ligandless dispersive liquid-liquid microextraction method has been developed for preconcentration of trace quantities of silver as a prior step to its determination by flame atomic absorption spectrometry. In the proposed approach, carbon tetrachloride and ethanol were used as extraction and dispersive solvents. Several factors that may be affected on the extraction process, like, extraction solvent, disperser solvent, the volume of extraction and disperser solvent, pH of the aqueous solution and extraction time were optimized. Under the optimal conditions, the calibration curve was linear in the range of 5.0 ng mL−1 to 2.0 μg mL−1 of silver with R2 = 0.9995 (n = 9) and detection limit based on three times the standard deviation of the blank (3Sb) was 1.2 ng mL−1 in original solution. The relative standard deviation for eight replicate determination of 0.5 μg mL−1 silver was ±1.5%. The high efficiency of dispersive liquid-liquid microextraction to carry out the determination of silver in complex matrices was demonstrated. The proposed method has been applied for determination of trace amount of silver in standard and water samples with satisfactory results. 相似文献
117.
Mehtab Parveen Raza Murad Ghalib Sayed Hasan Mehdi Rayees Ul Hasan Mattu Mohammed Ali 《Journal of Saudi Chemical Society》2009,13(3):287-290
The chloroform extract of the leaves of Ficus benjamina (var. comosa) (Moraceae) afforded a new triterpenic acid named as (9,11), (18,19)-disecoolean-12-en-28-oic acid (1) along with β-amyrin (2). Their structures were established on the basis of chemical and physical evidences (IR, 1H NMR, and MS data). The compound 1 exhibited significant antimicrobial activity against Salmonella typhimurium (MTCC-98), Candida albicans (IAO-109), Staphylococcus aureus (IAO-SA-22), Escherichia coli (K-12) and low activity against Aspergillus niger (lab isolate ICAR) and Aspergillus brassicola. 相似文献
118.
Confocal laser scanning microscopy (CLSM) was used to study single‐ and two‐component protein uptake for α‐lactalbumin (ALA) and β‐lactoglobulin (BLG), as models for whey proteins, to SP Sepharose FF at pH 3.7 during batch experiments in a finite bath. By coupling a fluorescent dye with the protein molecule, the penetration into individual adsorbent particles at different times during batch uptake was visualised. In a single‐component system, BLG penetrated fast into the adsorbent beads and gradually filled them in a shell‐wise fashion, while adsorption of ALA was mostly confined to the outer shells of the adsorbent. For the two‐component studies, the results showed that ALA was able to displace BLG despite its lower affinity to the adsorbent under the employed conditions. CLSM results were then compared both qualitatively and quantitatively to their counterparts obtained in traditional experiments by indirect measurements of the protein concentration in the fluid phase. A novel quantitative approach was undertaken by modifying the simple kinetic rate model traditionally used to determine the kinetic rate constant, k1, for batch uptake experiments, in order to describe batch uptake kinetics based on CLSM data. Although BLG results were in good agreement, there was a discrepancy in ALA results. 相似文献
119.
Ayesha Jacobs Luigi R. Nassimbeni Amina Sayed Edwin Weber 《Journal of chemical crystallography》2011,41(6):854-857
Abstract
Racemic 1,1′-binaphthyl-2,2′-dicarboxylic acid (BNDA) was resolved using quinine as the resolving agent. The structure of the resultant quininium (S)-1,1′-binaphthyl-2,2′-dicarboxylate dihydrate salt (1) was elucidated. The asymmetric unit contained one 1,1′-binaphthyl-2,2′-dicarboxylate anion, two quininium cations and two water molecules. The structure was solved successfully in the orthorhombic space group P212121 with unit cell dimensions: a = 11.100(2) ?, b = 16.572(3) ?, c = 28.726(6) ?. 相似文献120.
Raza Murad Ghalib Rokiah Hashim P. S. Pereira Silva Sayed Hasan Mehdi Othman Sulaiman Manuela Ramos Silva 《Journal of chemical crystallography》2011,41(11):1688-1693