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1.
Egyptian Journal of Chemistry. 2009; 52 (2): 193-216
em Inglês | IMEMR | ID: emr-135668

RESUMO

UV-visible and infrared absorption spectra of some selected commercial soda - lime - silicate glasses mixed with varied amounts of municipal glass cullet and doped with oxides of tin, manganese, and ceric before and after exposure to a high dose of gamma irradiation [5MR] were studied. XRF analysis showed that the municipal cullet contains high iron concentration and the results revealed that additions of [Mn + Ce + Sn] oxides produce colorless glasses even when containing high municipal cullet contents. It is generally observed that increasing the cullet content resulted in an optical spectrum consisting of three UV bands instead of two UV bands in case of low cullet content. The visible spectra reveal the resolution of two radiation induced bands at about 423 and 540 nm. Gamma irradiation also causes some of the absorption bands to be shifted in their positions. Experimental data are interpreted on the basis of current views on the spectroscopy of glasses


Assuntos
Hidróxido de Sódio/química , Vidro/análise , Espectrofotometria Ultravioleta/métodos , Espectrofotometria Infravermelho/métodos , Raios gama
2.
Egyptian Journal of Chemistry. 2007; 50 (5): 645-666
em Inglês | IMEMR | ID: emr-112265

RESUMO

This study presents the results of chemical durability of either commercial or prepared soda lime silicate glasses immersed in different aqueous solutions of [HC1, HNO[3], NaOH or H[2]O] for different duration. The chemical durability of the glasses was investigated by the weight loss determined per unit surface. The monovalent network modifier ion Na[+] is leached out more easily than the divalent cation Ca[2+], which is probably due to the stronger bond of the divalent cation Ca[2+] to the nonbridging oxygen sites in the glass. In explaining the results obtained two possible mechanisms [ion exchange leaching and matrix dissolution] were considered to explain .the release of cations from the glass structure in different aqueous solutions. The leaching mechanism involves the replacement of Na with a hydrogen bearing ion from the solution leading to the formation of surface layer, i.e. alkali depleted layer. The relative higher weight loss as a function of time, which characterizes the corrosion in alkaline media can be referred to the local rise of the solution pH, which could facilitate the dissolution of the glass Si-network. Also the results reveal that the commercial SLS has a very good durability at room temperature in the acidic medium. This durability decreases with the increase of temperature but at 100°C the glass durability increases again. Corrosion of gamma irradiated SLS shows a marked increase in weight loss as a function of time, and leads to a higher weight loss. Our results and interpretations were supported through FTIR reflectance and SEM investigations


Assuntos
Vidro/química , Raios gama , Corrosão , Silicatos , Óxidos , Hidróxido de Sódio , Compostos de Cálcio
3.
Egyptian Journal of Chemistry. 2003; 46 (1): 163-69
em Inglês | IMEMR | ID: emr-61938

RESUMO

Determination of uranium in phosphoric acid after extraction with tri-octyl phosphine oxide [TOPO] has been developed using I [2-pyridylazo] naphth-2- ol [PAN] as chromogenic reagents Glyoxal bis [2-hydroxyanil] [GBH], 1- [2-Pyridylazo] naphth-2-ol [PAN] in N, N dimethyl formamide and Arsenazo [III] were used as chromogenic reagents for Spectrophotometric determination of uranium after its extraction from ores by using TOPO. In previous reports, synthesis of ethyl hydrogen benzoyl phosphonate [HEBzOP] and its use as complexing agent for effective extraction of various transition and inner transition metal ions have been described. In this paper uranium in phosphate fertilizers of different origins was extracted with the HEBzOP and spectrophotometrically measured using quercetin as a chromogenic agent


Assuntos
Espectrofotometria Ultravioleta , Fertilizantes , Compostos Cromogênicos , Fosfatos
5.
Mansoura Journal of Pharmaceutical Sciences. 1995; 11 (1): 35-42
em Inglês | IMEMR | ID: emr-38233

RESUMO

From the roots of Torilis arvensis [Huds.] Link, crocatone, bergapten, xanthotoxin, scopoletin and umbelliferone were isolated and their structures were established through spectroscopic analyses. The present isolation of crocatone represents the first report of this isomyristicin derivative in the Scandiceae and the Caucalideae


Assuntos
Extratos Vegetais/análise , Cumarínicos/química
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