ab-initio modelling of Mg:H interstitial solid solutions

2003 ◽  
Vol 801 ◽  
Author(s):  
M. Messina ◽  
F. Cleri ◽  
M. Volpe
Keyword(s):  
Ab Initio ◽  
Solid Solutions ◽  
Minor Effect ◽  
Heat Of Solution ◽  
Volume Deformation ◽  
Subsequent Formation ◽  
Exchange Correlation ◽  
The Difference ◽  
A Minor ◽  
Structure Calculations

ABSTRACTWe studied the thermodynamics of interstitial Mg:H solid solutions by means of ab-initio electronic structure calculations. Soft pseudopotentials (Troullier-Martins) with non linear core correction and Perdew-Burke-Ernzerhof GGA exchange-correlation functional were employed, in the framework of a DFT plane-wave scheme. We inserted increasing concentrations of interstitial H atoms in the hcp Mg lattice, in both tetrahedral and octahedral positions. We calculated the heat of solution and the volume variation as a function of H concentration. Although the difference in Gibbs free energy is positive at any H concentration above 10−6 at.%, our results show that the enthalpic contribution is negative at any H concentration, therefore locally favouring H clustering. This reflects the existence of a driving force for the subsequent formation of the hydride. The volume deformation was characterized, finding that octahedreal interstitials have a minor effect, while tetrahedral interstitial can induce very large local expansion.

Influence of Cardiac Output on Plasma Propofol Concentrations during Constant Infusion in Swine

2002 ◽  
Vol 96 (6) ◽  
pp. 1498-1503 ◽  
Author(s):  
Tadayoshi Kurita ◽  
Koji Morita ◽  
Tomiei Kazama ◽  
Shigehito Sato
Keyword(s):  
Cardiac Output ◽  
Constant Infusion ◽  
Minor Effect ◽  
Inverse Relation ◽  
Peripheral Vein ◽  
Femoral Arteries ◽  
Drug Plasma ◽  
Concentration Changes ◽  
The Difference ◽  
A Minor

Background As propofol is a high-clearance drug, plasma propofol concentrations can be influenced by cardiac output (CO), which can easily change in response to several factors. If propofol is metabolized in the lungs, the difference between pulmonary and arterial propofol concentrations might also be affected by CO. The objective of the current study was to assess how much plasma propofol concentrations are affected by CO and to determine how much the lungs take part in propofol elimination and in concentration changes affected by CO in anesthetized swine. Methods Thirteen swine were studied. Propofol was administered via a peripheral vein at a rate of 6 mg x kg(-1) x h(- 1), and blood samples were simultaneously collected from pulmonary and femoral arteries at 0, 2, 3.5, 5, 7, 10, 20, and 30 min and at 20-min intervals up to 270 min. After 90 min of sampling (baseline 1), CO increased in response to a continuous infusion of dobutamine (20 microg x kg(-1) x min(- 1); high-CO state); the infusion was then stopped, and CO was allowed to return to baseline (baseline 2). Finally, CO decreased with the administration of propranolol (2.0-4.0 mg administered intravenously; low-CO state). Each hemodynamic status was maintained for 1 h. Results As CO increased 36% from baseline 1, plasma propofol concentrations decreased by 18% from baseline 1, and as CO decreased 42% from baseline 1, plasma propofol concentrations increased by 70% from baseline 1. Plasma propofol concentrations can be expressed by the following equation: plasma propofol concentration (micrograms per milliliter) = 6.51/CO (l/min) + 1.11 (r = 0.78, P < 0.0001). No significant differences were observed between plasma propofol concentrations in pulmonary and femoral arteries in any state, and CO caused no apparent differences between pulmonary and arterial propofol concentrations. Conclusions An inverse relation was observed between CO and propofol concentrations. The lungs appear to have a minor effect on plasma propofol concentrations during constant infusion in anesthetized swine.

scholarly journals Microstructure, Mechanical, Corrosion, and Ignition Properties of WE43 Alloy Prepared by Different Processes

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 728
Author(s):  
Drahomír Dvorský ◽  
Jiří Kubásek ◽  
Klára Hosová ◽  
Miroslav Čavojský ◽  
Dalibor Vojtěch
Keyword(s):  
Solid Solutions ◽  
Ignition Temperature ◽  
Processing Technique ◽  
Intermetallic Phases ◽  
Alloying Elements ◽  
Minor Effect ◽  
Corrosion Properties ◽  
Mechanical And Corrosion Properties ◽  
A Minor ◽  
We43 Alloy

This paper deals with the effect of microstructure condition on ignition temperature, mechanical and corrosion properties of commercial WE43 alloy prepared by various processing techniques including conventional casting, extrusion, and powder metallurgy methods such as spark plasma sintering. For different processing technique, differences in microstructures were observed, including different grain sizes, intermetallic phases, amount of alloying elements in the solid solutions, or specific structural elements. Mechanical and corrosion properties were improved especially by grain refinement. Precipitation from oversaturated solid solutions led to further improvement of mechanical properties, while corrosion resistance was just slightly decreased due to the fine and homogeneously distributed precipitates of Mg41Nd5. The obtained results indicate huge differences in ignition resistance based on the metallurgical state of the microstructure. An improved ignition resistance was obtained at the condition with a higher concentration of proper alloying elements (Y, Nd, Gd, Dy) in the solid solution and absence of eutectic phases in the microstructure. Thermally stable intermetallic phases had a minor effect on resulting ignition temperature.

scholarly journals FRESCO+: an improved O<sub>2</sub> A-band cloud retrieval algorithm for tropospheric trace gas retrievals

2008 ◽  
Vol 8 (3) ◽  
pp. 9697-9729 ◽  
Author(s):  
P. Wang ◽  
P. Stammes ◽  
R. van der A ◽  
G. Pinardi ◽  
M. van Roozendael
Keyword(s):  
Rayleigh Scattering ◽  
Cloud Fraction ◽  
Retrieval Algorithm ◽  
Minor Effect ◽  
Vertical Column ◽  
Cloud Parameters ◽  
Tropospheric No2 ◽  
Retrieval Scheme ◽  
The Difference ◽  
A Minor

Abstract. The FRESCO (Fast Retrieval Scheme for Clouds from the Oxygen A-band) algorithm has been used to retrieve cloud information from measurements of the O2 A-band around 760 nm by GOME, SCIAMACHY and GOME-2. The cloud parameters retrieved by FRESCO are the effective cloud fraction and cloud pressure, which are used for cloud correction in the retrieval of trace gases like O3 and NO2. To improve the cloud pressure retrieval for partly cloudy scenes, single Rayleigh scattering has been included in an improved version of the algorithm, called FRESCO+. We compared FRESCO+ and FRESCO effective cloud fractions and cloud pressures using simulated spectra and one month of GOME measured spectra. As expected, FRESCO+ gives more reliable cloud pressures over partly cloudy pixels. Simulations and comparisons with ground-based radar/lidar measurements of clouds shows that the FRESCO+ cloud pressure is about the optical midlevel of the cloud. Globally averaged, the FRESCO+ cloud pressure is about 50 hPa higher than the FRESCO cloud pressure, while the FRESCO+ effective cloud fraction is about 0.01 larger. The effect of FRESCO+ cloud parameters on O3 and NO2 vertical column densities (VCD) is studied using SCIAMACHY data and ground-based DOAS measurements. We find that the FRESCO+ algorithm has a significant effect on tropospheric NO2 retrievals but a minor effect on total O3 retrievals. The retrieved SCIAMACHY tropospheric NO2 VCDs using FRESCO+ cloud parameters (v1.1) are lower than the tropospheric NO2 VCDs which used FRESCO cloud parameters (v1.04), in particular over heavily polluted areas with low clouds. The difference between SCIAMACHY tropospheric NO2 VCDs v1.1 and ground-based MAXDOAS measurements performed in Cabauw, The Netherlands, during the DANDELIONS campaign is about −2.12×1014 molec cm−2.

A Microwave Study of Intrinsic Permeability of Mechanically Activated Powders of Fe-Based Alloys

2009 ◽  
Vol 152-153 ◽  
pp. 325-328
Author(s):  
D.A. Petrov ◽  
Eugene P. Yelsukov ◽  
Konstantin N. Rozanov ◽  
S.F. Lomaeva ◽  
Andrey V. Osipov ◽  
...  
Keyword(s):  
Eddy Currents ◽  
Frequency Dispersion ◽  
Microwave Frequency ◽  
Minor Effect ◽  
Intrinsic Permeability ◽  
Low Frequencies ◽  
Magnetic Performance ◽  
Powder Particles ◽  
The Difference ◽  
A Minor

The structure and microwave magnetic performance of Fe, Fe-Si-C, and Fe-Co-Si-C powders fabricated by mechanical milling has been studied. The study was aimed at revealing of the effect of shape, composition, and structure of the powder particles on the microwave frequency dispersion of permeability of the powder-filled composites in the frequency range of 0.1−3 GHz. At low frequencies, below 1 GHz, the main reason causing the differences in the microwave magnetic properties of the powders is the shape of powder particles. At higher frequencies, the magnetic performance is mainly due to the effect of eddy currents and is determined by the size of powder particles. The difference in the composition of the powders under study and, therefore, corresponding differences in intrinsic permeability of these have a minor effect on the microwave magnetic performance as compared to the effects of particle size and shape.

Effect of Somatic Comorbidity on Alleviation of Depressive Symptoms

2000 ◽  
Vol 34 (5) ◽  
pp. 755-761 ◽  
Author(s):  
Heimo Viinamäki ◽  
Antti Tanskanen ◽  
Jukka Hintikka ◽  
Juha Haatainen ◽  
Risto Antikainen ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Regression Analysis ◽  
The Other ◽  
Minor Effect ◽  
Somatic Comorbidity ◽  
The Difference ◽  
Independent Association ◽  
A Minor ◽  
Depressive Patients

Objective: The aim of this study was to investigate whether somatic comorbidity (SC) impedes recovery from depression. Method: The study design was naturalistic. Diagnosis of depression was confirmed by means of the Structured Clinical Interview for DSM-III-R (SCID). Changes in the symptom scales for those patients with somatic comorbidity (n = 75) were compared with corresponding changes in depressive patients without somatic comorbidity (n = 41) in a 6-month follow up. Results: Measured on the Hamilton and Beck scales, recovery rates of those with SC was only slightly lower to that of the others. The difference was statistically significant only in relation to the Hamilton scale. Forty-four per cent of those with SC and 42% of the other patients recovered from their depression (BDI score < 10 on follow up). Logistic regression analysis showed no independent association between recovery and somatic comorbidity. Conclusions: Moderate somatic comorbidity has only a minor effect on recovery from depression.

scholarly journals FRESCO+: an improved O<sub>2</sub> A-band cloud retrieval algorithm for tropospheric trace gas retrievals

2008 ◽  
Vol 8 (21) ◽  
pp. 6565-6576 ◽  
Author(s):  
P. Wang ◽  
P. Stammes ◽  
R. van der A ◽  
G. Pinardi ◽  
M. van Roozendael
Keyword(s):  
Rayleigh Scattering ◽  
Cloud Fraction ◽  
Retrieval Algorithm ◽  
Minor Effect ◽  
Vertical Column ◽  
Cloud Parameters ◽  
Tropospheric No2 ◽  
Vertical Column Density ◽  
The Difference ◽  
A Minor

Abstract. The FRESCO (Fast Retrieval Scheme for Clouds from the Oxygen A-band) algorithm has been used to retrieve cloud information from measurements of the O2 A-band around 760 nm by GOME, SCIAMACHY and GOME-2. The cloud parameters retrieved by FRESCO are the effective cloud fraction and cloud pressure, which are used for cloud correction in the retrieval of trace gases like O3 and NO2. To improve the cloud pressure retrieval for partly cloudy scenes, single Rayleigh scattering has been included in an improved version of the algorithm, called FRESCO+. We compared FRESCO+ and FRESCO effective cloud fractions and cloud pressures using simulated spectra and one month of GOME measured spectra. As expected, FRESCO+ gives more reliable cloud pressures over partly cloudy pixels. Simulations and comparisons with ground-based radar/lidar measurements of clouds show that the FRESCO+ cloud pressure is about the optical midlevel of the cloud. Globally averaged, the FRESCO+ cloud pressure is about 50 hPa higher than the FRESCO cloud pressure, while the FRESCO+ effective cloud fraction is about 0.01 larger. The effect of FRESCO+ cloud parameters on O3 and NO2 vertical column density (VCD) retrievals is studied using SCIAMACHY data and ground-based DOAS measurements. We find that the FRESCO+ algorithm has a significant effect on tropospheric NO2 retrievals but a minor effect on total O3 retrievals. The retrieved SCIAMACHY tropospheric NO2 VCDs using FRESCO+ cloud parameters (v1.1) are lower than the tropospheric NO2VCDs which used FRESCO cloud parameters (v1.04), in particular over heavily polluted areas with low clouds. The difference between SCIAMACHY tropospheric NO2 VCDs v1.1 and ground-based MAXDOAS measurements performed in Cabauw, The Netherlands, during the DANDELIONS campaign is about −2.12×1014molec cm−2.

Task repetition effects on L1 use in EFL child task-based interaction

2016 ◽  
Vol 21 (4) ◽  
pp. 480-495 ◽  
Author(s):  
Agurtzane Azkarai ◽  
María del Pilar García Mayo
Keyword(s):  
First Language ◽  
Minor Effect ◽  
Task Repetition ◽  
Repetition Effects ◽  
Efl Learners ◽  
L2 Learners ◽  
Procedural Task ◽  
The Difference ◽  
L1 Use ◽  
A Minor

Research has shown that tasks provide second language (L2) learners with many opportunities to learn the L2. Task repetition has been claimed to benefit L2 learning since familiarity with procedure and/or content gives learners the chance to focus on more specific aspects of language. Most research on task repetition has focused on adult populations, but child learners are an under-researched group. The same goes for first language (L1) use during L2 interaction, which has been mainly studied among adult L2 learners whereas little is known about L1 use among child L2 learners interacting while they complete communicative tasks. This study explores to what extent and for which purposes children in an English as a foreign language (EFL) setting use their shared L1 (Spanish). Furthermore it also considers how task repetition (exact vs. procedural task repetition) influences their L1 use. Forty-two EFL learners worked in pairs while they completed a spot-the-difference task twice. Our findings showed a significant decrease in L1 use when learners repeated the task in the two conditions but a minor effect of task repetition on the functions the L1 served.

Improvement of monitoring of tertiary filtration with particle counting

2006 ◽  
Vol 6 (1) ◽  
pp. 1-9
Author(s):  
V. Miska ◽  
J.H.J.M. van der Graaf ◽  
J. de Koning
Keyword(s):  
Particle Surface ◽  
Minor Effect ◽  
Particle Size Distributions ◽  
Particle Volume ◽  
Mass Distributions ◽  
Particle Counting ◽  
Total Particle ◽  
Particle Counts ◽  
A Minor ◽  
Sample Dilution

Nowadays filtration processes are still monitored with conventional analyses like turbidity measurements and, in case of flocculation–filtration, with phosphorus analyses. Turbidity measurements have the disadvantage that breakthrough of small flocs cannot be displayed, because of the blindness regarding changes in the mass distributions. Additional particle volume distributions calculated from particle size distributions (PSDs) would provide a better assessment of filtration performance. Lab-scale experiments have been executed on a flocculation–filtration column fed with effluent from WWTP Beverwijk in The Netherlands. Besides particle counting at various sampling points, the effect of sample dilution on the accuracy of PSD measurements has been reflected. It was found that the dilution has a minor effect on PSD of low turbidity samples such as process filtrate. The correlation between total particle counts, total particle volume (TPV) and total particle surface is not high but is at least better for diluted measurements of particles in the range 2–10 μm. Furthermore, possible relations between floc-bound phosphorus and TPV removal had been investigated. A good correlation coefficient is found for TPV removal versus floc-bound phosphorus removal for the experiments with polyaluminiumchloride and the experiments with single denitrifying and blank filtration.

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