BACKGROUND Previous studies on the use of SO2 and CO2 as impregnating agent for sugar cane bagasse steam treatment showed comparative and promising results concerning the cellulose enzymatic hydrolysis and the low formation of the inhibitors furfural and hydroxymethylfurfural for the use of CO2 at 205°C/15 min or SO2 at 190°C/5 min. In the present study sugar cane bagasse materials pretreated a...

sulfonated polystyrene/montmorillonite nanocomposite (ommt/ps-so3h) was prepared and used as a novel, efficient and inexpensive heterogeneous acid catalyst in the one-pot reaction three-component mannich reaction of ketones, aromatic aldehydes and amines under solvent-free conditions. the catalyst was characterized by xrd, sem, tg, bet and ft-ir techniques. this method has advantages of high yi...

diamond like carbon (dlc) film was grown by hot filament chemical vapor deposition (hfcvd)technique. in the present work, we investigated the quality of the dlc films groew on the substratesthat were coated with various metal nanocatalysts (au and ni). a combination of ch4/ar/h2 rendersthe growth of carbon nanostructures technique (diamond like carbon). the utilized samples werecharacterized by...

The current controversy about the "cohesion-tension" of water ascent in plants arises from the recent cryo-scanning electron microscopy (cryo-SEM) observations of xylem vessels content by Canny and coworkers (1995). On the basis of these observations it has been claimed that vessels were emptying and refilling during active transpiration in direct contradiction to the previous theory. In this s...

OBJECTIVES The purpose was to determine filter ventilation and the nicotine content of tobacco and their contribution to machine-smoked yields of cigarettes from the United States, Canada, and the United Kingdom. METHODS Ninety-two brands of cigarettes (32 American, 23 Canadian, and 37 British brands) were purchased at retail outlets in State College, Pennsylvania, United States, Toronto, Can...

Dual-beam focused ion beam microscopy (FIB/SEM) preparation of rock varnish for high-resolution transmission electron microscopy (HR-TEM) has enabled us to characterize unreported nanostructures. Fossils, unreported textures, and compositional variability were observed at the nanoscale. These techniques could provide a method for studying ancient terrestrial and extra-terrestrial environments t...