The plant, Centaurea perrottetii DC (Asteraceae) is a herbaceous thistle-like shrub used in traditional medicine for the treatment of malaria, fever, syphilis, ulcer and skin infections. aim study to isolate elucidate structure compound(s) from C. perrottetii. Quercetin-derivative (an amino-flavone) was isolated n-hexane fraction methanol extract whole plant using combination silica gel column ...

The aim of this study was to evaluate the various roles 1,3-DiPhenyl Guanidine (DPG) in silica-reinforced rubber compounds. Two DPG are well known be: adsorption onto silica surface reduce acidic sites and second boost silanization reaction as secondary accelerator. However, these two a way conflicting. When molecules occupy reactive silanol on by adsorption, then access silane needed for silic...

In this study, the interaction between the silica filler and polydimethylsiloxanes (PDMS) was investigated from the aspects of the bound rubber and morphological characterization. With special attention to the dynamic properties, the dynamic test was conducted by dynamic shear rheometer. The results show that the modified fillers disperse uniformly within PDMS matrix without aggregation and con...

In our study of the aging phenomena in silica suspensions we immersed precipitated silica particles in methyl-terminated PDMS (silicone oil), mineral oil, and glycerol/water and measured their viscoelastic properties as a function of time. We found that the samples based on silicone oil, initially of a pasty consistence, became fluid-like after a period of about three weeks. Aqueous samples age...

Salvia genus, which is generally called Maryam-Goli in the Persian language, belongs to Lamiaceae family and comprises 58 species in Iran. Four flavonoids plus a steroid compound were isolated from the ethyl acetate and methanol extracts of the aerial parts of Salvia macrosiphon Boiss, using different chromatographic methods on the silica gel and sephadex LH20. The structures of the isolated co...

Manganese oxide catalyst promoted with sodium and supported on silica exhibits fairly good activity and selectivity towards the synthesis of ethylene from methane at the optimum operating conditions. Methane and oxygen were fed into a tubular fixed bed reactor packed with catalyst under atmospheric pressure. The effects of temperature, residence time and feed composition on conversion, selectiv...

Abstract Semiconductor nanomaterials are often proposed as photocatalysts for wastewater treatment; silica still largely unexploited because their photocatalytic performances need improvements, especially under visible light. The present study is a proof-of-concept that amorphous colloids once submitted to the proper surface modifications change into an efficient photocatalyst even low-energy i...