The soot combustion mechanism over potassium-supported oxides (MgO, CeO2 and ZrO2) was studied to clarify the active sites and discover unified reaction intermediates in this typical gas-solid-solid catalytic reaction. The catalytically active sites were identified as free K(+) rather than K2CO3, which can activate gaseous oxygen. The active oxygen spills over to soot and forms a common interme...

Dietary administration of 5% L-ascorbic acid plus 3% K2CO3 to male F344 rats clearly enhanced the development of preneoplastic and neoplastic lesions of the urinary bladder initiated with N-butyl-N-(4-hydroxybutyl)nitrosamine. Promotion of carcinogenesis by L-ascorbic acid and K2CO3 was associated with changes in urinary parameters: elevation of pH, increased K+ concentration, and increase in t...

Exposure of the leaf canopy of corn seedlings (Zea mays L.) to atmospheric CO(2) levels ranging from 100 to 800 mul/l decreased nitrate accumulation and nitrate reductase activity. Plants pretreated with CO(2) in the dark and maintained in an atmosphere containing 100 mul/l CO(2) accumulated 7-fold more nitrate and had 2-fold more nitrate reductase activity than plants exposed to 600 mul/l CO(2...

13ETIiRMINATION of total iodine in various materials has become of increasing interest, especially in nutritional studies. Several methods are available for such determination. Many of them have been principally concerned with the protein-bound iodine fraction in serum (1, 2). Other methods for iodine determination have appeared from time to time. Mathews et al. (3) have proposed a method which...

 The equilibrium moisture content of malting barley grains (cv. Scarlett) was determined by gravimetric-static method in the range 20-50°C using saturated salt solutions (LiCl, MgCl2.6H2O, K2CO3, NaBr, NaNO2, KI, NaNO3, NaCl, (NH4)2SO4) to provide water activities for each temperature between 0.11 and 0.813. Desorption isotherms were obtained at 20, 30, 40, and 50°C. All the sorption curves w...

cerium oxide (ceo2) or ceria has been shown to be an interesting support material for noble metals in catalysts designed for emission control, mainly due to its oxygen storage capacity. ceria nanoparticles were prepared by precipitation method. the precursor materials used in this research were cerium nitrate hexahydrate (as a basic material), potassium carbonate and potassium hydroxide (as pre...

The aim of this work was to obtain a black coffee brew to be consumed hot by extension of its shelf life, by addition of additives. Four pH-regulator agents (sodium and potassium carbonates and bicarbonates), one pH regulator and antioxidant (sodium citrate), three antioxidants [sodium ascorbate, ethylenediaminetetracetic acid (EDTA), and sodium sulfite], and lactoserum were tested by sensory a...