Search results for "Limiting oxygen concentration"
showing 10 items of 39 documents
Ein neuartiges Verfahren der Sauerstoffdetektion für Medizin, Biologie, Umweltforschung und Biotechnik auf Basis der Lumineszenzlöschung - An Innovat…
1996
For most (aerobic) animal organisms, oxygen is a mandatory and global substrate. The accurate measurement of oxygen is therefore of importance in the fields of medicine, biology, environmental research and biotechnology. The fact that oxygen is not readily soluble in aqueous media makes its detection more difficult. In contrast to the technique of polarography, the use of luminescence quenching by paramagnetic oxygen, does not consume the oxygen. Another problem of oxygen detection in connection with respiration is the need for very short response times. A third problem, which is associated with luminescence itself, is the fading of the dyes, which results in long-term signal instability. T…
Mechano-activated processes on metal oxide interfaces at room temperature
1997
Solid state bonding of metal with oxide at room temperature have been studied. The properties of Al/SiO 2 , Al/glass, Al/MgO, Mg/SiO 2 , In/glass interfaces as well as to ascertain the mechanism of formation of interfaces. Structure, composition and mechanical properties were investigated using auger-spectroscopy (AES), secondary-ion mass-spectrometry (SIMS), electron microscopy and precision microindentation. The results showed marked adhesion not all over contact area but only at zones of the maximum shear stress. The effect of mechanoactivation is considered from the viewpoints of both structure formation and physico- chemical interaction of nonequilibrium systems. As a result of relaxat…
Interface of Silicon Nitride Nanolayers with Oxygen Deficiency
2018
Multilayer Si 3 N 4 consisting of Si 3 N 4 nanolayers with the total thickness 60 nm was deposited layer-by-layer in a low-pressure chemical vapor deposition process. Compared with the single-layer Si 3 N 4 , the multilayer Si 3 N 4 had one-third less oxygen concentration at the interfaces. This decreased density of electrically active centers of oxygen traps and improved quality of nanocapacitors with multilayer Si 3 N 4 dielectric.
Reduction of temperature coefficients in multicrystalline silicon solar cells after light-induced degradation
2015
This study focuses on the variations of the temperature coefficients after light-induced degradation (LID) of compensated multicrystalline silicon solar cells from three different ingots. The ingots have been chosen to see the effect of the compensation level, the resistivity and the impact of adding gallium to keep the resistivity as constant as possible along the ingot. The temperature coefficients of the efficiency experience a major decrease after LID on all ingots. We found that this decrease varies along the ingot height and does not correspond to the VOC drop. Moreover, no direct correlation with the interstitial oxygen concentration profiles could be seen.
OXYGEN SOLUBILITY IN NORMAL HUMAN BLOOD
1981
Publisher Summary This chapter describes oxygen solubility in normal human blood. The most crucial problem in measuring physically dissolved oxygen in blood is the prevention of oxygen binding by hemoglobin (Hb). The chapter discusses a study for the re-determination of oxygen solubility in untreated human blood. The oxygen concentration was measured by a photometric method and the Hb-concentration was determined by the cyanohemoglobin method. Oxygen solubility in normal and untreated blood is a linear function of the Hb-concentration. Hemoglobin in the reduced state has a greater influence on oxygen solubility than hemoglobin. Red cell membranes have no measureable effect on the oxygen sol…
Emissions and spatial variability of N2O, N2 and nitrous oxide mole fraction at the field scale, revealed with 15N isotopic techniques.
2006
Abstract The accurate measurement of nitrous oxide (N 2 O) and dinitrogen (N 2 ) during the denitrification process in soils is a challenge which will help to estimate the contribution of soil N 2 O emissions to global warming. Oxygen concentration, nitrate concentration and carbon availability are generally the main factors that control soil denitrification rate and the amount of N 2 O or N 2 emitted. The aim of this paper is to present a database of the N 2 O mole fraction measured at the field scale, and to test hypotheses concerning its regulation. A 15 N-nitrate tracer solution was added to 36 undisturbed soil cores on a 20 m×20 m cultivated field plot. Fluxes of CO 2 , N 2 O and N 2 f…
Effect of O2 control and monitoring on the nutraceutical properties of extra virgin olive oils
2016
Abstract The presence of oxygen during malaxation has key role in improving Extra Virgin Olive Oil (EVOO) quality in terms of volatile and phenolic compounds. The objective of this study was to evaluate the influence of the head space malaxer oxygen concentration on the physicochemical characteristics and nutraceutical properties of EVOO from the Nocellara del Belice olives. The acidic compounds were related to the concentration of the oxygen presented in the machine headspace considering a new software application for the online oxygen management opportunely designed and applicable to all the existing plants. The right timepoint and oxygen concentration of the malaxation process was establ…
Effect of Mechanoactivation on Interfacial Interaction in Metal/Oxide Systems
2006
Properties of interfaces in solid state metal/oxide joints (Al/SiO2, Al/MgO, Al/glass, Mg/MgO, Mg/SiO2, In/glass etc.) are reported. The interfaces were formed by plastic deformation of metal on the oxide surface at room temperature. Their structure, chemical composition, and micromechanical properties were studied by the AFM, XRD, SIMS, optical microscopy, and precision microindentation techniques. A noticeable adhesion was observed for metals with high affinity for oxygen and only in the regions of the maximum shear stress. Formation of an interfacial reaction zone with an oxygen concentration gradient is detected. In this zone metals are nanostructured and noticeably hardened. The effect…
Relevance of Oxygen Concentration in Stem Cell Culture for Regenerative Medicine
2019
The key hallmark of stem cells is their ability to self-renew while keeping a differentiation potential. Intrinsic and extrinsic cell factors may contribute to a decline in these stem cell properties, and this is of the most importance when culturing them. One of these factors is oxygen concentration, which has been closely linked to the maintenance of stemness. The widely used environmental 21% O2 concentration represents a hyperoxic non-physiological condition, which can impair stem cell behaviour by many mechanisms. The goal of this review is to understand these mechanisms underlying the oxygen signalling pathways and their negatively-associated consequences. This may provide a rationale…
Body size variability across habitats in the Brachionus plicatilis cryptic species complex
2020
AbstractThe body size response to temperature is one of the most recognizable but still poorly understood ecological phenomena. Other covarying environmental factors are frequently invoked as either affecting the strength of that response or even driving this pattern. We tested the body size response in five species representing the Brachionus plicatilis cryptic species complex, inhabiting 10 brackish ponds with different environmental characteristics. Principal Component Analysis selected salinity and oxygen concentration as the most important factors, while temperature and pH were less influential in explaining variation of limnological parameters. Path analysis showed a positive interclo…