The seasonal melting of ice entombed cryoconite holes on McMurdo Dry Valley glaciers provides oases for life in the harsh environmental conditions of the polar desert where surface air temperatures only occasionally exceed 0°C during the Austral summer. Here we follow temporal changes in cryoconite hole biogeochemistry on Canada Glacier from fully frozen conditions through the initial stages of...

Metal electrodeposition may introduce various morphological variations depending on the electrolytic conditions including cell configurations. For liquid electrolytes, a precise study of these deposits may be complicated by convective motion due to buoyancy. Zero-gravity (0-G) condition provided by drop shaft or parabolic flight gives a straightforward mean to avoid this effect: we present here...

a simple and mild procedure for the conversion of anilines into aryl isocyanates is described using the 3-hydroxypropylammonium acetate (hpaa) ionic liquid as a novel and efficient media has been explored in the synthesis of aryl isocyanates from the reaction of substituted urea with sodium nitrite in a water immiscible solvent. this ionic liquid can be easily recovered and reused for many time...

We investigate the effects of the relative dielectric coefficient on ionic flows in open ion channels, using mathematical analysis of reasonably general Poisson-Nernst-Planck type models that can include the finite sizes of ions. The value of the relative dielectric coefficient is of course a crucial parameter for ionic behavior in general. Using the powerful theory of singularly perturbed prob...

BACKGROUND Failure to achieve isonatric haemodialysis (HD) drives an expansion of extracellular volume leading to increased interdialytic weight gain (IDWG). This may be a causative factor in the development of HD-induced cardiac injury. We examined total and diffusive sodium mass balance during HD. METHODS 24 chronic HD patients using a fixed 140 mmol/l sodium concentration were studied over...

the solubility of k2so4 in water at 25°c was determined. comparing the value ofthermodynamic solubility product constant, ksp(th), (ksp(th) = exp (-δgodiss rt) of the mentionedsalt to the value of concentration solubility product, ksp(c) which is obtained from the observedsolubility, s/mol-1, ksp(c) = 4s3, revealed a great difference. the difference can be satisfactorilyexplained using debye- h...

Article history: Received 11 March 2009 Accepted 16 March 2009 Available online 20 March 2009 Communicated by V.M. Agranovich A simple description of the electrode potential based on the selective ionic adsorption is proposed. It is shown that if the adsorption–desorption coefficients entering in the Langmuir kinetic equation for the adsorption at the limiting surfaces are not identical, a diff...

A theory is presented for lambdaC, the coefficient of the first-order correction in the density of the collective diffusion coefficient, for protein spheres interacting by electrostatic and adhesive forces. An extensive numerical analysis of the Stokesian hydrodynamics of two moving spheres is given so as to gauge the precise impact of lubrication forces. An effective stickiness is introduced a...

the protonation constant values of salicylic and 5-nitrosalicylic acid werestudied by a combinationof spectrophotometric and potentiometric methods at 25 °c in wide range of ionic strength. the ionicstrength of solutions was kept constant by sodium perchlorate as background electrolyte at 0.10 to 3.0 moldm-3. potentiometer was calibrated according to gran method at each of ionic strength. the p...

nanofiltration-based separation processes have found diverse applications in industrial and environmentalproblems recently, due to several advantages such as lower energy requirement and elevated flux ratescompared with their reverse osmosis (ro) counterparts. several attempts have been made for modellingnf-based separation processes ranging from rigorous space-charge approaches to simpler irre...