Search results for "proper"
showing 10 items of 3167 documents
Partial molar volumes of cobalt(II) chloride in ethanol + water at 298.15 K
1996
Densities of ethanol + water + cobalt(II) chloride mixtures have been measured with an oscillating-tube densimeter over a large range of concentrations of salt, at 298.15 K. From these densities, apparent molar volumes of the electrolyte in these mixtures have been calculated, and partial molar volumes at infinite dilution have been evaluated, at different concentrations of alcohol in the solvent.
Thermodynamics of Solubilization of Pentanol in Sodium Dodecyl Sulfate-Dodecyldimethylamine Oxide Mixed Micelles
1994
Abstract Heat capacity and density measurements of pentanol (PeOH)-sodium dodecyl sulfate (NaDS)-dodecyldimethylamine oxide-water mixtures were carried out at 0.03 m PeOH as a function of the total surfactants concentration (mc) at different ratios (XNaDS). From experimental data, the apparent molar volumes (VΦ,R) and heat capacities (CΦ,R) of PeOH in the surfactants mixture solutions were calculated. As a general feature, at a given mixture composition, VΦ,R increases monotonically with mt as observed in pure surfactants. In the cases of XNaDS = 0.1 and 0.3, VΦ,R drops at about 0.1 and 0.15 mt respectively. The decreasing CΦ,R VS mt curve shows peculiarities which were ascribed to the pres…
Apparent molar volumes of lithium nitrate in 1-propanol + water in the temperature range from 288.15 to 318.15 K
2002
Abstract Densities of 1-propanol+water+lithium chloride mixtures have been measured with an oscillating-tube densimeter over a large range of concentrations of the salt and 1-propanol at 288.15, 298.15, 308.15, and 318.15 K. From these densities, apparent molar volumes of lithium chloride in 1-propanol+water mixtures have been calculated for each temperature, and apparent molar volumes at infinite dilution have been evaluated. An empirical correlation for partial molar volumes of lithium chloride in 1-propanol+water mixtures with solvent composition and temperature has been derived.
Structural Characterization of Zirconia Nanoparticles Prepared by Microwave-Hydrothermal Synthesis
2009
Nanocrystalline zirconia powders have been prepared by microwave-hydrothermal synthesis starting from aqueous solution of ZrOCl2·8H2O. Results of investigations on the aqueous suspension stability of the washed zirconia nanopowders by dynamic light scattering showed that the suspension, constituted by superaggregates of nanoparticles (131 ± 10 nm), was stable up to 15 days. Nanopowders were investigated by means of transmission electron microscopy and small angle x-ray scattering measurements which proved that the zirconia nanopowder is constituted by small primary nanoparticles of ca. 8 nm that agglomerate forming bigger aggregates of 50 ± 1 nm.
Dioxygen reduction by cobalt(II) octaethylporphyrin at liquid|liquid interfaces.
2010
Oxygen reduction catalyzed by cobalt(II) (2,3,7,8,12,13,17,18-octaethylporphyrin) [Co(OEP)] at soft interfaces is studied by voltammetry and biphasic reactions. When Co(OEP) is present in a solution of 1,2-dichloroethane in contact with an aqueous acidic solution, oxygen is reduced if the interface is positively polarized (water phase versus organic phase). This reduction reaction is facilitated when an additional electron donor, here ferrocene, is present in excess in the organic phase.
Proton coordination by polyamine compounds in aqueous solution
1999
Abstract The present article is concerned with proton transfer reactions in aqueous solution of open-chain, macrocyclic and macropolycyclic or cage compounds having nitrogen atoms as protonation sites in the molecular framework, although several compounds with additional different donors will be considered. The main purpose of this review is to collect some significant examples of proton transfer processes in order to show how the electronic properties and molecular topology of polyamines affect the thermodynamic parameters of their protonation equilibria.
Thermal and Chemical Stability of Thiol Bonding on Gold Nanostars
2015
The stability of thiol bonding on the surface of star-shaped gold nanoparticles was studied as a function of temperature in water and in a set of biologically relevant conditions. The stability was evaluated by monitoring the release of a model fluorescent dye, Bodipy-thiol (BDP-SH), from gold nanostars (GNSs) cocoated with poly(ethylene glycol) thiol (PEG-SH). The increase in the BDP-SH fluorescence emission, quenched when bound to the GNSs, was exploited to this purpose. A maximum 15% dye release in aqueous solution was found when the bulk temperature of gold nanostars solutions was increased to T = 42 °C, the maximum physiological temperature. This fraction reduces 3-5% for temperatures …
Water-Soluble Polysaccharides from Ephedra alata Stems: Structural Characterization, Functional Properties, and Antioxidant Activity
2020
In this study, the physicochemical characterization, functional properties, and antioxidant activity of polysaccharides extracted from Ephedra alata (EAP) were investigated. EAP were extracted in water during 3 h with a liquid/solid ratio of 5 in a water bath at 90 °
Semiclassical Methods for the Description of Large Metal Clusters
1996
One of the most fascinating aspects of clusters is that they can be made arbitrarily large and therefore provide links between the microscopic and the macroscopic world. It is challenging to study how their physical properties change when going from atoms and small molecules to the bulk limit of condensed matter. But also the models and mathematical tools themselves, which are used in order to tackle the many-body problem, are an object of study for the theoretician. In particular, the question of how far quantum-mechanics must be carried with increasing size and where classical pictures become appropriate is of great interest. In this spirit, we discuss here some semiclassical methods for …
La Cumparsita: a source of lawsuits Contursi and Maroni vs. Matos Rodríguez
2016
This article deploys Tango along with the lawsuits concerning to whom participated in the elaboration of “La Cumparsita” and its lyrics as a frame of reference for discussing about copyrights and intellectual property. In addition to giving an opinion about the procedure to arrive at the final solution related to the adjudication of the copyrights along its effects of that in each one of the beneficiaries, the author tell us a little bit of the process of creating this musical composition as well as the scope it had during its time. El presente artículo utiliza al Tango, a los pleitos y personajes que participaron en la elaboración de La cumparista y sus letras, como marco referencial para …