Search results for "saturation"
showing 10 items of 478 documents
Gas—liquid chromatographic analyses
1984
Abstract The gas chromatography (GC) of n -alkyl acetates (CH 3 COOR), chloroacetates (CH 2 ClCOOR), dichloroacetates (CHCl 2 COOR) and trichloroacetates (CCl 3 COOR), where the alcohol chain length (R) varied between 1 and 8, and certain of their monochlorinated derivatives, 176 compounds altogether, has been studied on SE-30 and OV-351 glass capillary columns under the same operating conditions. The isomeric monochlorinated esters are eluted in direct order from the 1- chloro to the ω-chloro isomer, the separation of the isomers being complete on OV- 351. On SE-30, however, the peaks of the 6- and 7-chlorooctyl esters are partly overlapped. The separation of the mixtures of odd- and e…
Der O2-Austausch zwischen Capillaren und Gewebe I. O2-Konzentrationsprofile in Blutcapillaren und deren Umgebung
1968
The differential equations valid for technical heat exchangers can also describe the O2 exchange in the blood capillaries and the exchange of molecules like THO and acetamid in the renal tubules. Differences in the boundary conditions occur, however. Hence, these differential equations were resolved for the corresponding boundary conditions. The results permit us to conclude that the concentration profiles occurring in the capillaries and renal tubules, as a result of diffusion in the capillary cross-section, can, generally speaking, be disregarded for the following reason: Although the differences in partial pressure between the capillary wall and capillary centre, at the beginning of the …
Experimental investigation of calcium silicate hydrate (C-S-H) nucleation
1999
Due to the importance of calcium silicate hydrate (C-S-H) in cement chemistry, its nucleation mode and parameters influencing it were investigated. It has been observed that the C-S-H nucleation follows the general laws governing the nucleation. The degree of supersaturation has been found to be the main parameter controlling homogeneous nucleation rates. The lime concentration in solution, well known to be the most important parameter determining the kinetic, morphological and structural features of C-S-H, also controls the nucleation characteristics of heterogeneous nucleation, i.e. during hydration of cement. The correlation between heterogeneous nucleation of C-S-H and possible final me…
Saturated Solutions of Anhydrous Phases in the System Lime-Silica-Water: Example of beta-C2S
1990
Saturated solutions rerely form when the anhydrous constituents of aluminous and portland cement are stirred in water or in lime solutions of increasing concentrations. Apart from monocalcium aluminate, concentration of ions in solution cannot exceed maximum supersaturation with respect to the hydrate most likely to precipitate. The present work shows such a behavior for β-C2S suspended in water and in lime solutions at low concentration. In more concentrated lime solutions, a short lifetime saturation state with respect to β-C2S seems to be reached.
Effects of temperature on electron paramagnetic resonance of dangling oxygen bonds in amorphous silicon dioxide
2011
The properties of electron paramagnetic resonance (EPR) signal of oxygen dangling bonds in amorphous SiO2 ("non-bridging oxygen hole centers", NBOHC) in excimer laser-irradiated amorphous SiO2 were studied in the temperature range 20K to 295K. NBOHCs strongly affect optical and chemical properties of amorphous SiO2 -based (nano) structures and their surfaces. The behaviour of their EPR signal is complicated due to a nearly degenerate electronic ground state. It was found that EPR signal has a non-Curie (~1/T) T-dependence down to 40K, indicating that EPR-based concentration estimates routinely obtained at T = 77K underestimate the center concentrations at least by a factor of 1.7. The estim…
Electrothermal Atomic Absorption Spectrometric Diagnosis of Familial Hypercholesterolemia
2000
We have developed a new nonradioactive assay to identify human low-density lipoprotein receptor defects. It is based on the incubation of cultured cells with colloidal gold-LDL conjugates and quantitation of the gold associated with the cells by electrothermal atomic absorption spectrometry. After an oxidative treatment with nitric and hydrochloric acids, the biological matrix interferes neither with the gold recovery nor with the gold measurements, which are linear, at least from 0.15 to 3 ng of gold. When cells expressing a functional LDL receptor are incubated with increasing amounts of colloidal-gold LDL conjugates, the obtained saturation curve parallels that described when [125I]LDL i…
Gas—liquid chromatographic analyses
1985
Abstract The gas chromatographic retention behaviour of methylethyl, 1-methylpropyl, 2-methylpropyl, 1,2-dimethylpropyl, 1-methylbutyl and 3-methylbutyl esters of benzoic and o-, m- and p-chlorobenzoic acids on low-polarity (SE-30) and polar (OV-351) capillary columns under several temperature-programmed and isothermal conditions is reported. The retention data and the Kovats retention indices for all 24 components are given and the separation of a complex mixture is discussed. The retention index increments have been used to examine the effects of chain branching and chlorine substitution. The results are compared with those for n-alkyl benzoates and monochlorobenzoates.
From connected pathway flow to ganglion dynamics
2015
During imbibition, initially connected oil is displaced until it is trapped as immobile clusters. While initial and final states have been well described before, here we image the dynamic transient process in a sandstone rock using fast synchrotron-based X-ray computed microtomography. Wetting film swelling and subsequent snap off, at unusually high saturation, decreases nonwetting phase connectivity, which leads to nonwetting phase fragmentation into mobile ganglia, i.e., ganglion dynamics regime. We find that in addition to pressure-driven connected pathway flow, mass transfer in the oil phase also occurs by a sequence of correlated breakup and coalescence processes. For example, meniscus…
Impact of temperature on obstructive sleep apnoea in three different climate zones of Europe: Data from the European Sleep Apnoea Database (ESADA)
2021
Recent studies indicate that ambient temperature may modulate obstructive sleep apnoea (OSA) severity. However, study results are contradictory warranting more investigation in this field. We analysed 19,293 patients of the European Sleep Apnoea Database (ESADA) cohort with restriction to the three predominant climate zones according to the Koppen-Geiger climate classification: Cfb (warm temperature, fully humid, warm summer), Csa (warm temperature, summer dry, hot summer), and Dfb (snow, fully humid, warm summer). Average outside temperature values were obtained and several hierarchical regression analyses were performed to investigate the impact of temperature on the apnea-hypopnea index …
EXPLANATORY FACTORS OF MARKET POWER IN THE BANKING SYSTEM
2007
The aim of the study is to analyse the explanatory factors of market power in the banking system. Using as laboratory the Spanish banking system in the period 1986–2002, results show an increase of market power from the mid-1990s. Of the set of variables that the model posits as explaining market power, those with the greatest explanatory power are size, efficiency and specialization; concentration is not significant. This last result shows the limitations of the approaches, studies and decision-making rules of economic policy that uses market concentration as a proxy for the degree of competition.