scholarly journals Equilibrium partial pressure of CO2 in Callovian–Oxfordian argillite as a function of relative humidity: Experiments and modelling

2016 ◽  
Vol 186 ◽  
pp. 91-104 ◽  
Author(s):  
Arnault Lassin ◽  
Nicolas C.M. Marty ◽  
Hélène Gailhanou ◽  
Benoît Henry ◽  
Joachim Trémosa ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Partial Pressure ◽  
Equilibrium Partial Pressure ◽  
Partial Pressure Of Co2

scholarly journals Equilibrium Partial Pressure of CO2 in the Callovo-Oxfordian Argillite as a Function of Relative Humidity

2013 ◽  
Vol 7 ◽  
pp. 459-462 ◽  
Author(s):  
Arnault Lassin ◽  
Nicolas Marty ◽  
Benoît Henry ◽  
Joachim Trémosa ◽  
Hélène Gailhanou ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Partial Pressure ◽  
Equilibrium Partial Pressure ◽  
Partial Pressure Of Co2

scholarly journals A Simple and Accurate Approach for Determining the VFA Concentration in Anaerobic Digestion Liquors, Relying on Two Titration Points and an External Inorganic Carbon Analysis

2021 ◽  
Vol 5 (2) ◽  
pp. 15
Author(s):  
Paz Nativ ◽  
Yonatan Gräber ◽  
Yaron Aviezer ◽  
Ori Lahav
Keyword(s):  
Partial Pressure ◽  
Volatile Fatty Acids ◽  
Inorganic Carbon ◽  
Strong Acid ◽  
Direct Analysis ◽  
Anaerobic Digesters ◽  
Acid Titration ◽  
Partial Pressure Of Co2 ◽  
Ph Range

A new analytic approach is presented for determining the total volatile fatty acids (VFAT) concentration in anaerobic digesters. The approach relies on external determination of the inorganic carbon concentration (CT) in the analyzed solution, along with two strong-acid titration points. The CT concentration can be determined by either a direct analysis (e.g., by using a TOC device) or by estimating it from the recorded partial pressure of CO2(g) in the biogas (often a routine analysis in anaerobic digesters). The titration is carried out to pH 5.25 and then to pH 4.25. The two titration results are plugged into an alkalinity-mass-based equation and then the two terms are subtracted from each other to yield an equation in which VFAT is the sole unknown (since CT is known and the effect of the total orthophosphate and ammonia concentrations is shown to be small at this pH range). The development of the algorithm and its verification on four anaerobic reactor liquors is presented, on both the raw water and on acetic acid-spiked samples. The results show the method to be both accurate (up to 2.5% of the expected value for VFAT/Alkalinity >0.2) and repetitive when the total orthophosphate and ammonia concentrations are known, and fairly accurate (±5% for VFAT >5 mM) when these are completely neglected. PHREEQC-assisted computation of CT from the knowledge of the partial pressure of CO2(g) in the biogas (and pH, EC and temperature in the liquor) resulted in a very good estimation of the CT value (±3%), indicating that this technique is adequate for the purpose of determining VFAT for alarming operators in case of process deterioration and imminent failure.

Effect of vegetation on limestone solution in a small High Arctic basin

1977 ◽  
Vol 14 (4) ◽  
pp. 571-581 ◽  
Author(s):  
Ming-Ko Woo ◽  
Philip Marsh
Keyword(s):  
Carbon Dioxide ◽  
Partial Pressure ◽  
Soil Water ◽  
Water Hardness ◽  
Late Summer ◽  
Arctic Basin ◽  
The Arctic ◽  
Total Hardness ◽  
Equilibrium Partial Pressure ◽  
Biogenic Carbon

To evaluate the effect of tundra vegetation on limestone solution processes, the present study was carried out in a small basin in southwestern Ellesmere Island, N.W.T. A test reach was selected along the stream, and water samples were collected at regular intervals from a seepage point entering the reach, a soil water pit at the bottom of a vegetated slope along the test reach, and from the stream at the outlet of the reach. Hydrochemical characteristics of the samples were described by several measured and calculated variables including water temperature, pH, calcium and total hardness, bicarbonate concentration, equilibrium partial pressure of carbon dioxide, and indices of saturation with respect to calcite and dolomite. Throughout the growing season of 1975, all samples indicated higher concentrations in water hardness and in bicarbonate than those reported in nonvegetated areas of the Arctic. A rising trend was apparent in these data, with the concentrations reaching a seasonal maximum in late summer. These phenomena are attributed to the production of biogenic carbon dioxide, which increased the aggressiveness of the water. The partial pressure of carbon dioxide in soil water was directly increased by this process, while the addition of soil water to the stream caused noticeable downstream increase in partial pressure of carbon dioxide and a corresponding reduction in saturation with respect to calcite and to dolomite. The influence of vegetation was therefore very marked in both surface and in subsurface flows.

scholarly journals Hurricane Arthur and its effect on the short-term variability of pCO<sub>2</sub> on the Scotian Shelf, NW Atlantic

2017 ◽  
Author(s):  
Jonathan Lemay ◽  
Helmuth Thomas ◽  
Susanne E. Craig ◽  
William J. Burt ◽  
Katja Fennel ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Carbon Cycling ◽  
Dissolved Inorganic Carbon ◽  
High Temporal Resolution ◽  
Co2 Uptake ◽  
Surface Mixed Layer ◽  
Scotian Shelf ◽  
Short Term ◽  
Partial Pressure Of Co2 ◽  
Short Term Variability

Abstract. The understanding of seasonal variability of carbon cycling on the Scotian Shelf, NW Atlantic Ocean, has improved in recent years, however, very little information is available regarding its short-term variability. In order to shed light on this aspect of carbon cycling on the Scotian Shelf we investigate the effects of Hurricane Arthur, which passed the region on July 5th 2014. The hurricane caused a substantial decline in the surface water partial pressure of CO2 (pCO2), even though the Scotian Shelf possesses CO2 rich deep waters. High temporal resolution data of moored autonomous instruments demonstrate that there is a distinct layer of relatively cold water with low dissolved inorganic carbon (DIC) slightly above the thermocline, presumably due to a sustained population of phytoplankton. Strong storm-related wind mixing caused this cold intermediate layer with high phytoplankton biomass to be entrained into the surface mixed layer. At the surface, phytoplankton begin to grow more rapidly due to increased light. The combination of growth and mixing of low DIC water led to a short-term reduction in partial pressure of CO2 until wind speeds relaxed and allowed for the restratification of the upper water column. These Hurricane-related processes caused a (net-) CO2 uptake by the Scotian Shelf region that is comparable to the spring bloom, thus exerting a major impact on the annual CO2 flux budget.

Inhibition of CO2 Assimilation by Supraoptimal CO2: Effect of Light and Temperature

1983 ◽  
Vol 10 (1) ◽  
pp. 75 ◽  
Author(s):  
KC Woo ◽  
SC Wong
Keyword(s):  
Partial Pressure ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Quantum Yields ◽  
Co2 Partial Pressure ◽  
Low Co2 ◽  
O2 Partial Pressure ◽  
Partial Pressures ◽  
High Partial Pressure ◽  
Partial Pressure Of Co2

In cotton the rate of CO2 assimilation, at O2 partial pressures up to 200 mbar, increased to a maximum and then declined as the intercellular partial pressure of CO2 was increased. The specific intercellular partial pressure of CO2 at which rate of assimilation began to decline depended on the environmental conditions. At 19 mbar partial pressure of O2 the decline occurred at CO2 partial pressure >390 �bar. At 200 mbar partial pressure of O2 it occurred at CO2 partial pressure > 534 �bar. O2 increased the CO2 partial pressure required for inhibition but it did not appear to affect the steepness of the decline of rate of assimilation with further increase in partial pressure of CO2 once the decline became apparent. The decline was more readily observed at low temperature and low O2 partial pressure, and in plants grown at low light and NO3- levels. It was also observed in cowpea and sunflower. Changes in quantum efficiency in cotton at high and low CO2 concentrations were observed. At ambient CO2 concentration (300 �bar), the quantum yields measured at 19 and 200 mbar partial pressure of O2 were 0.072 � 0.0003 and 0.053 � 0.0060 mol CO2 per mol absorbed quanta, respectively. In contrast, at 900 �bar CO2 partial pressure the respective values were 0.050 � 0.0023 and 0.070 � 0.0006 mol CO2 per mol absorbed quanta. The nature of the inhibition of CO2 assimilation by high partial pressure of CO2 is discussed.

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