CO2 sorption kinetic study and modeling on doped-Li4SiO4 under different temperatures and CO2 partial pressures

2020 ◽  
Vol 379 ◽  
pp. 122307 ◽  
Author(s):  
Eleonora Stefanelli ◽  
Monica Puccini ◽  
Sandra Vitolo ◽  
Maurizia Seggiani
Keyword(s):  
Kinetic Study ◽  
Sorption Kinetic ◽  
Co2 Sorption ◽  
Partial Pressures ◽  
Different Temperatures

scholarly journals Impact of ocean acidification and elevated temperatures on early juveniles of the polar shelled pteropod <i>Limacina helicina</i>: mortality, shell degradation, and shell growth

2010 ◽  
Vol 7 (6) ◽  
pp. 8177-8214 ◽  
Author(s):  
S. Lischka ◽  
J. Büdenbender ◽  
T. Boxhammer ◽  
U. Riebesell
Keyword(s):  
Ocean Acidification ◽  
Surface Waters ◽  
Elevated Temperatures ◽  
Shell Growth ◽  
Shell Diameter ◽  
Partial Pressures ◽  
Limacina Helicina ◽  
Different Temperatures ◽  
Arctic Surface

Abstract. Due to their aragonitic shell thecosome pteropods may be particularly vulnerable to ocean acidification driven by anthropogenic CO2 emissions. This applies specifically to species inhabiting Arctic surface waters that are projected to become locally undersaturated with respect to aragonite as early as 2016. This study investigated the effects of rising pCO2 partial pressures and elevated temperature on pre-winter juveniles of the polar pteropod Limacina helicina. After a 29 days experiment in September/October 2009 at three different temperatures and under pCO2 scenarios projected for this century, mortality, shell degradation, shell diameter and shell increment were investigated. Temperature and pCO2 had a significant effect on mortality, but temperature was the overriding factor. Shell diameter, shell increment and shell degradation were significantly impacted by pCO2 but not by temperature. Mortality was 46% higher at 8 °C compared to 3 °C (in situ), and 14% higher at 1100 μatm CO2 as compared to 230 μatm CO2. Shell diameter and increment were reduced by 10% and 12% at 1100 μatm CO2 as compared to 230 μatm CO2, respectively, and shell degradation was 41% higher at elevated compared to ambient pCO2 partial pressures. We conclude that pre-winter juveniles will be negatively affected by both rising temperature and pCO2 which may result in a possible abundance decline of the overwintering population, the basis for next year's reproduction.

A field versus laboratory study of blood oxygen status in normoxic crabs at different temperatures

1996 ◽  
Vol 74 (3) ◽  
pp. 423-430 ◽  
Author(s):  
J.-C. Massabuau ◽  
J. Forgue
Keyword(s):  
Wide Spectrum ◽  
Venous Blood ◽  
Carcinus Maenas ◽  
Blood Oxygen ◽  
Arterial Blood ◽  
Field Versus ◽  
Partial Pressures ◽  
Different Temperatures ◽  
Head Pressure ◽  
Oxygen Status

The blood oxygen status of two species of active crabs (Carcinus maenas and Necora puber) was studied in the field and compared with the results of previous laboratory experiments performed on a wide spectrum of physiologically different water-breathers. The aim was to determine whether, as in the laboratory, the functioning of the O2 supply system in the field could be based on maintaining the arterial [Formula: see text] in the low range, 1–3 kPa. The O2 partial pressures and concentrations in the arterial and venous blood, arterial blood pH, and blood respiratory pigment concentration were measured in normoxic water at various temperatures ranging from 10 to 20 °C and in various seasons. In the field, [Formula: see text] values in normoxic C. maenas and N. puber were in the low range, 1–3 kPa, independently of temperature, season, and blood haemocyanin concentration. It is concluded that in the field as in the laboratory, [Formula: see text] values mainly in the low range provide a head pressure sufficient to meet O2 needs. The changes that appear to occur in other respiratory variables are discussed in relation to field versus laboratory conditions and temperature differences. The consequences for analysing problems of hypoxaemia in hypoxic waters or situations are discussed.

Analysis of the water vapour sorption behaviour of Sitka spruce [Picea sitchensis (Bongard) Carr.] based on the parallel exponential kinetics model

Holzforschung ◽  
2010 ◽  
Vol 64 (4) ◽  
Author(s):  
Callum A.S. Hill ◽  
Andrew Norton ◽  
Gary Newman
Keyword(s):  
Water Vapour ◽  
Sitka Spruce ◽  
Sorption Kinetics ◽  
Picea Sitchensis ◽  
Sorption Kinetic ◽  
Sorption Behaviour ◽  
Water Vapour Sorption ◽  
Vapour Sorption ◽  
Different Temperatures

Abstract The water vapour sorption behaviour of Sitka spruce was analysed based on the parallel exponential kinetics (PEK) model. The PEK model deconvolutes the sorption kinetics curve into two exponential kinetics processes (fast and slow) which have characteristic times and moisture contents associated with them. The sorption kinetics was examined at different temperatures enabling the determination of activation energies for the sorption kinetic processes throughout the hygroscopic range (from 5% to 95% relative humidities). The physical interpretation of the PEK model is also discussed.

Si-N nanowire formation from Silicon nano and microparticles.

2003 ◽  
Vol 789 ◽  
Author(s):  
Chandana Rath ◽  
A. Pinyol ◽  
J. Farjas ◽  
P. Roura ◽  
E. Bertran
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Crystalline Silicon ◽  
Silica Layer ◽  
Whisker Formation ◽  
Low Oxygen ◽  
Partial Pressures ◽  
Precursor Material ◽  
Different Temperatures ◽  
First Time

ABSTRACTWe report silicon nitride whisker formation from hydrogenated amorphous silicon (a-Si:H) nanoparticles grown by PECVD for the first time. We compared the results with the kinetics of whisker formation from ball milled crystalline silicon (c-Si) microparticles. Whisker formation is analyzed at different temperatures (900–1440 °C) and oxygen partial pressures. At temperatures equal or above 1350 C and at low oxygen partial pressure we observe monocrystalline α-Si3N4 whiskers having 30–100 nm diameter and several microns length. By increasing the oxygen partial pressure, the structure of whiskers is completely changed, as shown by electron microscopy. In this case we observe α-Si3N4 whiskers covered by an amorphous silica layer at 1350 C. Finally, when the precursor material is silicon microparticles, thicker (170–330 nm) and longer whiskers are formed.

scholarly journals Hydrogen Uptake of Duplex 2205 at H2 Partial Pressures up to 100 bar

2019 ◽  
Vol 165 (1) ◽  
pp. 40-45 ◽  
Author(s):  
Anton Trautmann ◽  
Gregor Mori ◽  
Wolfgang Siegl ◽  
Mathias Truschner ◽  
Josefine Pfeiffer ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Hydrogen Embrittlement ◽  
Duplex Stainless Steel ◽  
Hydrogen Uptake ◽  
Constant Load ◽  
Gas Reservoir ◽  
Partial Pressures ◽  
Different Temperatures ◽  
Steel Grades ◽  
Load Tests

AbstractMicrobiological methanation is investigated in an underground natural gas reservoir. Since H2 is involved in the process, hydrogen embrittlement of steel must inevitably be considered. Therefore, a routine for testing has been developed and a unique autoclave test bench was designed to simulate field conditions. The 2205 duplex stainless steel (UNS S31803) was investigated. Constant load tests (CLTs) and immersion tests with subsequent hydrogen analyses were performed. The specimens were exposed to different partial pressures of H2 under both dry and wet conditions (with brine). Additionally, the influence of CO2 under wet conditions was covered. Tests were performed at two different temperatures (25 °C and 80 °C) and lasted for 30 days. In general, the duplex stainless steel shows a good resistance to hydrogen embrittlement, but a significantly higher hydrogen uptake was obtained compared to other steel grades.

Kinetic Study of the Epimerization of 1,1,1-Trichloro-2-hydroxy-3-methyl-4-hexanone

1973 ◽  
Vol 51 (19) ◽  
pp. 3182-3186 ◽  
Author(s):  
Eberhard Kiehlmann ◽  
Fred Masaro ◽  
Frederick J. Slawson
Keyword(s):  
Activation Energy ◽  
Acetic Acid ◽  
Kinetic Study ◽  
Glacial Acetic Acid ◽  
Initial Reaction ◽  
First Order ◽  
Kinetically Controlled ◽  
Different Temperatures ◽  
Pseudo First Order

The acetate-catalyzed epimerization of 1,1,1-trichloro-2-hydroxy-3-methyl-4-hexanone has been studied in glacial acetic acid as solvent at five different temperatures. The reaction follows pseudo first-order, reversible kinetics and is associated with an activation energy of 24.0 ± 0.4 kcal/mol. Rate and product studies have shown that epimerization occurs by an enolization–ketonization pathway rather than dehydration–rehydration or retroaldol–aldolization. The ratio of diastereomeric ketols formed by condensation of 2-pentanone and 2-heptanone with chloral does not change as a function of time while the stereochemistry of the chloral addition to cyclohexanone is kinetically controlled during the initial reaction period.

KINETICS OF THE CUPRIC ACETATE CATALYZED HYDROGENATION OF DICHROMATE IN AQUEOUS SOLUTION

1955 ◽  
Vol 33 (2) ◽  
pp. 356-364 ◽  
Author(s):  
E. Peters ◽  
J. Halpern
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Partial Pressure ◽  
Kinetic Study ◽  
Reaction Rates ◽  
Homogeneous Catalyst ◽  
Cupric Acetate ◽  
Partial Pressures ◽  
Kinetics Of

In aqueous solution, cupric acetate was found to act as a homogeneous catalyst for the reduction of dichromate by hydrogen, i.e.[Formula: see text] The paper describes a kinetic study of this reaction. Rates were determined at temperatures between 80° and 140 °C. and hydrogen partial pressures up to 27 atmospheres. The rate is independent of the dichromate concentration but varies directly with the partial pressure of hydrogen and is nearly proportional to the concentration of cupric acetate. The activation energy is 24,600 calories per mole. Cupric acetate, apparently acting as a true catalyst, activates the hydrogen through formation of a complex with it. An extension of the mechanism proposed earlier for the reaction of cupric acetate itself with hydrogen also accounts for the kinetics of the dichromate reaction.

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