Search results for " Purity"
showing 10 items of 18 documents
Dependence of Perceived Purity of a Chromatic Stimulus on Saturation Adaptation
2012
Background and Objective. The purpose of sensory adaptation of the visual system is to adjust sensitivity of the photoreceptors to optimize the dynamic range of response of the visual system. It has been shown in numerous research papers that chromatic adaptation influences both color appearance and color discrimination. However, there are almost no studies in which the influence of chromatic adaptation on perceived purity has been investigated. Therefore, the aim of this study was to investigate how chromatic adaptation to stimuli with certain saturation influences perceived purity of test stimuli with the same hue but different saturation. Material and Methods. As the stimuli were modulat…
Mixing against culture vs mixing against nature: ontologization of prohibited interethnic relationships.
2009
In this paper, we develop the theory of ontologization: Social representations that prevent members of minority and majority groups who are living in contact with each other to mingle. The process of ontologization consists of separating some humans from their own species, and anchoring them in another environment, that of an animal, for example. We propose that underlying the famous slogan "equal but separate" is the social representation of interracial mixing as a "counter-nature" phenomenon. It is predicted that a sexual relationship between people of different "races" leads to a greater degree of ontologization, and, as such, this miscegenation will be explained in terms of biologistic …
SINGLE-PEAK RESOLUTION CRITERIA FOR OPTIMIZATION OF MOBILE PHASE COMPOSITION IN LIQUID CHROMATOGRAPHY
2001
Three criteria that evaluate the single peak resolution (peak purity) in chromatography, the free height fraction, free area fraction, and valley ratio, are examined. The main advantages of these criteria against other criteria based on peak pair separation, are that the measurements are not affected by the identity of neighboring peaks and are normalized, which make them very intuitive. The methodology is illustrated through the isocratic separation of mixtures of several sulphonamides (sulphacetamide, sulphadiazine, sulphadimethoxine, sulphaguanidine, sulphamerazine, sulphamethazine, sulphamethoxazole, sulphamethizole, sulphamonomethoxine, sulphanilamide, sulphapyridine, sulphaquinoxaline…
Ein schnelles on-line trennsystem unter anwendung von helium-jet- und zentrifugentechnik
1975
Abstract A centrifuge for continuous liquid-liquid phase separation is described. It is designed for rapid solvent extraction of short-lived radioactive isotopes (half-lives in the order of seconds). The centrifuge is characterized by simple construction and operation principle, easy handling, low cost, and a minimum hold-up time of less than five seconds (phase purity 99.0–99.9%). The on-line connection to a helium-jet transport system is described. Problems concerning the transfer of activities into a liquid phase from the helium-jet at atmospheric pressure are discussed.
Robust interpretive optimisation in high-performance liquid chromatography considering uncertainties in peak position.
2005
In the context of interpretive chromatographic optimisation, robustness is usually calculated by introducing deliberated shifts in the nominal optimal conditions and evaluating their effects on the monitored objective function, mimicking thus the experimental procedures used in method validation. However, such strategy ignores a major source of error: the uncertainties associated to the modelling step, that may give rise to deceiving results when conditions that were expected to yield baseline separation are reproduced in the chromatograph. Two approaches, based on the peak purity concept, are here proposed to evaluate the robustness of the objective function under the perspective of measur…
Limits of multi-linear gradient optimisation in reversed-phase liquid chromatography
2005
Abstract The concept of limiting peak purity was applied to quantify the degree of completion of the separation capability of a chromatographic system using multi-linear gradients. The objective was to check whether the complexity of a gradient program deserves be increased to enhance resolution by inserting more linear segments, or on the contrary, no significant improvements can be expected under more complex gradients. A set of 19 isoindole derivatives of primary amino acids was selected to test the performance of isocratic, single linear and multi-linear gradients. Accurate simulated chromatograms were obtained via numerical integration of the general equation of gradient elution, using…
From Spain to Sicily after the Expulsion: Conversos between Economic Networks and the Aristocratic Elite
2018
Abstract This article focuses on a group of conversos families from Spain, who established themselves in Palermo after the Expulsion of the Jews in 1492. There they supported financial activities of the Nazione Catalana and established strong relationships with the local aristocracy. Thanks to this alliance, they managed to avoid persecution by the Spanish Inquisition, “cleanse” their “impure” blood and reach high positions within politics and society: feudal titles, political and financial offices, habits of military orders, ecclesiastical appointments and sometimes even sainthood. Firstly, the paper will give a brief sketch of the phenomenon of conversos in Sicily as well as the activitie…
Considerations on the modelling and optimisation of resolution of ionisable compounds in extended pH-range columns
2005
Abstract The problems associated to the modelling and optimisation of the chromatographic resolution of mixtures involving ionisable solutes at varying pH and acetonitrile content are discussed. Several retention models that separate the contributions of solute, column and stationary phase, were used. The retention was predicted with low errors in large pH domains (2–12), which was an essential requirement to face the optimisation of resolution. The selected mixture was particularly problematic under the viewpoint of resolution, owing to the excessively diverse acid–base behaviour of solutes. This variety led to sudden drops in retention at different pH for each solute, yielding numerous pe…
The Design and Sensitivity of JUNO's scintillator radiopurity pre-detector OSIRIS
2021
The European physical journal / C 81(11), 973 (2021). doi:10.1140/epjc/s10052-021-09544-4
A diamond (1 0 0) surface with perfect phase purity
2015
Abstract Diamond surfaces with (1 0 0) orientation and perfect phase purity regarding the coexistence of sp3 and sp2 bonding as well as near surface nitrogen implanted layers are repeatedly produced from one sample by a cycle of nitrogen implantation, etching in oxygen and wet chemical etching. Comprehensive surface studies carried out by X-ray photoelectron spectroscopy (XPS) involving a deconvolution of the C 1s peak into contributions of C sp3, C sp2 and C sp3(N) reveal the surface and near-surface phase and stoichiometry. It is demonstrated that efficient etching of nitrogen implanted diamond occurs by high temperature annealing in oxygen and a wet chemical treatment.