The surface physical-chemical characteristics of a class F coal fly ash were studied in an effort to establish a quantitative understanding of metal adsorption. The ash surface acidity (acid site density and acidity constant), surface electrical characteristics, and adsorption constants for selected heavy metal ions were determined using a batch titration method, an electrophoretic method, and ...

1. The decrease in the rate of growth of a population of yeast cells, which results in the maintenance of an equilibrium crop level, is shown to be due to substances excreted into the culture medium by the growing cells. These toxic substances tend to destroy the young buds, because the percentage of budding cells is about the same at the time of most rapid growth and at the time of the growth ...

The solvent extraction of Fe from aqueous chloride solution by bis-(2,4,4-trimethylpentyl) monothiophosphinic acid (Cyanex 302, H2A2) dissolved in kerosene has been investigated over a wide range of aqueous acidity as a function of phase contact time, concentrations of Fe, H and Cl in the aqueous phase, Cyanex 302 concentration in the organic phase and temperature. The equilibration time is 50 ...

In this paper, we report the most comprehensive equilibrium superacidity scale that is available to date. Contrary to most of the past works, this scale is set up in a medium of constant composition and the obtained acidity values characterize the acidities of molecules rather than acidities of media. The current scale is thus complementary to the well-known H(0) scale in the information that i...

In tropical regions, soil acidity and low soil fertility are the most important yield-limiting factors for sustainable crop production. Using legume cover crops as mulch is an important strategy not only to protect the soil loss from erosion but also to ameliorate soil fertility. Information is limited regarding tolerances of tropical legume cover crops to acid soils. A greenhouse experiment wa...

Thermodynamics of extraction of Zn2+ from sulfuric acid media contacting to a mixture of DEHPA and MEHPA diluted with 80 wt% aromatic-aliphatic kerosene with a constant DEHPA to MEHPA ratio is investigated at different acidities, concentrations and temperatures. As a result, the extraction reaction is found to be endothermic with a zinc distribution factor that increases with increasing of the ...

An attempt was made to understand the changes in physicochemical quality (total soluble solids, titratable acidity, ascorbic acid, total sugars, total phenolics, anthocyanin content, and cupric reducing antioxidant capacity assay) and total volatile/aroma compounds of two cultivars of strawberry (Camarosa and Chandler) during storage at 5°C for 9 days at an interval of three days. Observations ...

AIMS Somatostatin analogues (e.g. vapreotide) are used for treatment of acromegaly, endocrine tumours and variceal bleeding. The pharmacodynamic effects of vapreotide have, however, not been documented in the gastrointestinal tract. The aim of this study was to investigate the effects of continuous vapreotide administration on gastric acidity, gallbladder contraction and hormone release. METH...

To understand more fully the role of the in vivo turtle shell in buffering lactic acid produced during prolonged anoxia, powdered turtle shell was incubated in vitro at constant pH (6.0, 6.5, 7.0, 7. 5 or 8.0) in electrolyte solutions simulating extracellular fluid. Exchanges of ions and CO2 between the shell and solution were evaluated by measuring pre- and post-incubation solution concentrati...