A Theoretical Prediction of the Normal Cardiac Oxygen Consumption

The diffusion, solubility, and permeability behavior of oxygen and carbon dioxide were studied in amorphous and semicrystalline syndiotactic polystyrene (s‐PS). The crystallinity was induced in s‐PS by crystallization from the melt and cold crystallization. Crystalline s‐PS exhibited very different gas permeation behavior depending on the crystallization conditions. The behavior was attributed to the formation of different isomorphic crystalline forms in the solid‐state structure of this polymer. The β crystalline form was virtually impermeable for the transport of oxygen and carbon dioxide. In contrast, the α crystalline form was highly permeable for the transport of oxygen and carbon dioxide. High gas permeability of the α crystals was attributed to the loose crystalline structure of this crystalline form containing nanochannels oriented parallel to the polymer chain direction. A model describing the diffusion and permeability of gas molecules in the composite permeation medium, consisting of the amorphous matrix and the dispersed crystalline phase with nanochannels, was proposed. Cold crystallization of s‐PS led to the formation of a complex ordered phase and resulted in complex permeation behavior. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2519–2538, 2001

Effect of Nitrogen On the Solubility And Diffusivity of Carbon Dioxide Into Oil And Oil Recovery By the Immiscible WAG Process T.A. Nguyen; T.A. Nguyen Petroleum Recovery Institute Search for other works by this author on: This Site Google Scholar S.M. Farouq Ali S.M. Farouq Ali Petroleum Recovery Institute Search for other works by this author on: This Site Google Scholar Paper presented at the Annual Technical Meeting, Calgary, Alberta, June 1995. Paper Number: PETSOC-95-64 https://doi.org/10.2118/95-64 Published: June 06 1995 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Get Permissions Search Site Citation Nguyen, T.A., and S.M. Farouq Ali. "Effect of Nitrogen On the Solubility And Diffusivity of Carbon Dioxide Into Oil And Oil Recovery By the Immiscible WAG Process." Paper presented at the Annual Technical Meeting, Calgary, Alberta, June 1995. doi: https://doi.org/10.2118/95-64 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search nav search search input Search input auto suggest search filter All ContentAll ProceedingsPetroleum Society of CanadaPETSOC Annual Technical Meeting Search Advanced Search AbstractIn the immiscible displacement of oil by carbon dioxide gas, the solution and diffusion of carbon dioxide are important factors that determine the efficiency of the process, since an increase in the carbon dioxide solubility and diffusivity into oil leads to an increase in oil recovery because the oil phase left behind contains more carbon dioxide and less oil. It is shown by experimental studies that the solubility and diffusivity of carbon dioxide into oil are governed by the saturation pressure, reservoir temperature I composition of the oil and purity of the gas. The solubility and diffusivity of carbon dioxide into Aberfeldy heavy oil were measured, using impure carbon dioxide gas containing nitrogen as the main ontaminant gas. It was noted that increasing the concentration of nitrogen in the carbon dioxide stream ecreased the solubility and. diffusivity of carbon dioxide into oil, consequently leading to a reduction in the swelling oil of by carbon dioxide.Displacement experiments were also conducted to observe the effect of using impure carbon dioxide in place of pure carbon dioxide in the immiscible displacement WAG process. It was noted that the presence of nitrogen in carbon dioxide adversely affected oil recovery by the process and that increasing the nitrogen concentration up to 30 mole% could result in 10% loss in oil recovery.IntroductionThe solubility of carbon dioxide is the most important effect in the immiscible displacement of oil by carbon dioxide gas since it is theorized that among other mechanisms, an increase in the carbon dioxide solubility in oil leads to an increase in oil recovery because the oil phase left behind contains more carbon dioxide and less oil.Early work in 1926 by Beecher and Parkhurst1 showed that carbon dioxide was more soluble on a molar basis in a 30.2 °API oil than air and natural gas. Svreck and Mehrotra's data2 also showed that, among the three gases: carbon dioxide methane, and nitrogen, carbon dioxide is the most soluble and nitrogen the least soluble in bitumen.The solubility of carbon dioxide in oil is governed by the saturation pressure, reservoir temperature, composition of the oil and purity of the gas. Miller and Jones3 and Chung, Jones, and Nguyen4 measured the solubility of carbon dioxide n Canyon and Wilmington heavy oils and found that the solubility of carbon dioxide in heavy crude oils increased with pressure but decreased with temperature and reduced API gravity. Later, Sayegh and Sarbar5 established that carbon dioxide is more soluble in oil at lower temperatures than at higher ones. Patton, Coats, and Spence6, Holm and Josendal7, and Chung et al4 showed that the solubility of carbon dioxide reduced with me presence of methane in oil since carbon dioxide had to displace methane before dissolving in oil Holm and Josendal7 also mentioned that carbon dioxide did not displace all of the methane when it came into contact with oil. Spivak and Chima noted that the solubility of pure carbon dioxide in oil was higher than that of a carbon dioxide-nitrogen mixture. Keywords: upstream oil & gas, dioxide, petroleum society, experiment, oil recovery, pvt measurement, carbon dioxide, carbon dioxide solubility, nitrogen, carbon dioride Subjects: Fluid Characterization, Improved and Enhanced Recovery, Phase behavior and PVT measurements This content is only available via PDF. 1995. Petroleum Society of Canada You can access this article if you purchase or spend a download.

Ventilator-induced Lung Injury

BackgroundIron supplementation, especially in female athletes, is 1 of the influential factors in aerobic capacity, and its deficiency can lead to significant problems related to reduced aerobic capacity. ObjectivesThis study aimed to investigate the effect of 3 wk of iron supplementation on the aerobic capacity of female handball players. MethodsIn this randomized, double-blinded, and placebo control trial, 14 elite handball players (age: 21.6 ± 5.68 y; height: 169.5 ± 4.9 cm; weight: 62.2 ± 9.25 kg; body mass index (in kg/m2): 21.5 ± 2.9) randomly divided into 2 supplement groups (receiving a 100 mg/d of poly-maltose tri hydroxide iron complex in the form of tablets) and the placebo group (receiving a tablet containing 100 mg/d starch which is the same color and shape as iron tablets). The supplementation protocol was performed for 3 wk during the off-season. Maximal oxygen consumption (VO2max), amounts of carbon dioxide at the first ventilatory threshold, amounts of carbon dioxide at the second ventilatory threshold, time to exhaustion (TTE), pulmonary ventilation (VE), ventilatory equivalents for oxygen, amounts of oxygen at the first ventilatory threshold, amounts of oxygen at the second ventilatory threshold, time to reach first ventilatory threshold, end-tidal partial pressure of oxygen at the first ventilatory threshold, end-tidal partial pressure of carbon dioxide at the first ventilatory threshold and ventilatory equivalents for carbon dioxide were measured using the Bruce test and gas analyzer in 2 pretest and posttest stages. ResultsThere were significant improvements in oxygen at the first ventilatory threshold, time to reach first ventilatory threshold, and end-tidal partial pressure of carbon dioxide at the first ventilatory threshold and a significant decrease in end-tidal partial pressure of oxygen at the first ventilatory threshold (P < 0.05). Also, no significant changes were found in VO2max, carbon dioxide at the first ventilatory threshold, carbon dioxide at the second ventilatory threshold, oxygen at the second ventilatory threshold, TTE, VE, ventilatory equivalents for oxygen, and ventilatory equivalents for carbon dioxide after 3 wk of iron supplementation (P > 0.05). ConclusionsThe study found that 3 wk of off-season iron supplementation positively impacted female handball players’ aerobic capacity; however, it did not significantly improve their VO2max.

In the immiscible displacement of oil by carbon dioxide gas, the solubility and diffusivity of carbon dioxide are important factors that determine the efficiency of the process, because an increase in the carbon dioxide solubility and diffusivity into oil leads to an increase in oil recovery. It is shown by experimental studies that the solubility and diffusivity of carbon dioxide into oil are governed by the saturation pressure, reservoir temperature, composition of the oil and purity of the gas. The solubility and diffusivity of carbon dioxide into Aberfeldy heavy oil were measured, using impure carbon dioxide gas containing nitrogen as the main contaminant gas. It was noted that increasing the concentration of nitrogen in the carbon dioxide stream decreased the solubility and diffusivity of carbon dioxide in oil, consequently leading to a reduction in the swelling of the oil by carbon dioxide. Displacement experiments were also conducted to observe the effect of using impure carbon dioxide in place of pure carbon dioxide in the immiscible displacement WAG process. It was noted that the presence of nitrogen in carbon dioxide adversely affected oil recovery by the process and that increasing the nitrogen concentration up to 30 mole% could result in 10% loss in oil recovery. Introduction The solubility of carbon dioxide is the most important effect in the immiscible displacement of oil by carbon dioxide gas since it was found by Rojas(1) that among other mechanisms, an increase in the carbon dioxide solubility in oil leads to an increase in oil recovery. This is true because the solubility of carbon dioxide greatly reduces the viscosity of the oil and promotes the swelling of the oil. Viscosity reduction and swelling of the oil lower the water-oil mobility ratio, consequently leading to an increased oil recovery. Early work in 1926 by Beecher and Parkhurst(2) showed that carbon dioxide was more soluble on a molar basis in a 30.2 °API oil than air and natural gas. Svreck and Mehrota's data(3) for carbon dioxide, methane and nitrogen showed that and Mehrotra's data(3), carbon dioxide is the most soluble and nitrogen the least soluble in bitumen. The solubility of carbon dioxide in oil is governed by the saturation pressure, reservoir temperature, composition of the oil and purity of the gas. Miller and Jones(4) and Chung, Jones, and Nguyen(5) measured the solubility of carbon dioxide in Canyon and Wilmington heavy oils and found that the solubility of carbon dioxide in heavy crude oils increased with pressure but decreased with temperature and reduced API gravity. Briggs and Puttagunta(6) reported sets of data for carbon dioxide solubility in Aberfeldy oil and swelling of oil at 20.6 °C. Their data showed that both carbon dioxide solubility and oil swelling increased when pressure increased. Later, Sayegh and Sarbar(7) established that carbon dioxide is more soluble in oil at lower temperatures than at higher ones.

The effect of pressure on diffusivity in binary or multicomponent systems such as gas−liquid or gas−solid systems has rarely been reported. The diffusivity of carbon dioxide in extruded gelatinized starch has been measured in this study at pressures of up to 117 bar (1700 psi). Such data are fundamentally not only useful in the understanding of the supercritical carbon dioxide (SC-CO2)/starch systems but also can be useful for the design and control of processes utilizing carbon dioxide injection or mixing in starch-based matrices. The methodology developed here was an improvement over a previously reported technique, enabling high-pressure data to be obtained. The diffusivity of carbon dioxide in the melt was found to be a strong function of pressure but not of moisture content in the range of 34.5−39% (w/w) studied. This diffusivity value decreased from 7.5 × 10-10 to 0.9 × 10-10 m2/s as pressure was increased from atmospheric to 115 bar. The low-pressure diffusivity value was only an order of magnitude lower than that reported for a carbon dioxide in water system and comparable to reported values of diffusivity of CO2 in softened polymers. These diffusivity values are also the same order of magnitude as the reported values of the diffusivity of water in starch, suggesting similar mechanisms of diffusion for carbon dioxide and water diffusivity in starch. The observed pressure dependency of the diffusivity may be due to the melt's high compressibility at these pressures. The solubility of carbon dioxide in the starch melt was proportional to the product of the solubility of carbon dioxide in water and the melt's moisture content.

The Diffusion of Oxygen, Carbon Dioxide, and Inert Gas in Flowing Blood

The numerical solutions of diffusion equations have been obtained for the cases of oxygen and carbon dioxide diffusing through blood flowing between two porous parallel planes. It is assumed that at the entrance to the channel the concentration profiles are uniform and the velocity profile is fully developed. The rheological characteristics of blood are described by the Casson equation. The computations have been made employing the explicit finite-difference forward-marching procedure. The results have been obtained for a wide range of yield numbers, inlet partial pressures, pH, membrane resistances and haemoglobin concentrations.

Diffusivity is a strong function of concentration and an important transport property. Diffusion of multiple species is far more frequent than the diffusion of one species. However, there are limited experimental data available on multi-component diffusivity. The objective of this study is to develop an optimal control framework to determine multi-component concentration-dependent diffusivities of two gases in a non-volatile phase such as polymer. In Part 1 of this study, we derived a detailed mass-transfer model of the experimental diffusion process for the non-volatile phase to provide the temporal masses of gases in the polymer. The determination of diffusivities is an inverse problem involving principles of optimal control. Necessary conditions are determined to solve this problem. In Part 2 of this study, we utilized the results of Part 1 to determine the concentration-dependent, multi-component diffusivities of nitrogen and carbon dioxide in polystyrene. To that end, solubility and diffusion experiments are conducted to obtain necessary data. In the ternary system of nitrogen (1), carbon dioxide (2), and polystyrene (3), the diffusivities and D11, D12, D21, and D22 versus the gas mass fractions are two-dimensional surfaces. The diffusivity of carbon dioxide was found to be greater than that of nitrogen. The value of the main diffusion coefficient D11 was found to increase as the concentration of carbon dioxide increased. The highest value of D11 obtained was 2.2 X 10^-8m^2s^-1 for nitrogen mass fraction of 3.14 X10^-4 and for a carbon dioxide mass fraction of 5.67 X 10^-4 . The cross-diffusion coefficient increased as the concentrations of nitrogen and carbon dioxide increased. The diffusivity reached its maximum value when the concentrations of nitrogen and carbon dioxide were at their maximum values. The diffusivity was of the order of 10^-9m^2s^-1. The diffusivity of the cross-diffusion coefficient D21 was found to be increased for the mass The diffusivity of the cross-diffusion coefficient was found to be increased for the mass fractions of carbon dioxide ranging from 0 to 1.70 X 10^-3 . The diffusivity was found to be of the order of . The diffusion coefficient, D22, was found to increase with the concentrations of nitrogen and carbon dioxide, D22 remained high with low concentrations of carbon dioxide. The diffusivity was found to be of the order of 10^-7m^2s^-1

Diffusivity is a strong function of concentration and an important transport property. Diffusion of multiple species is far more frequent than the diffusion of one species. However, there are limited experimental data available on multi-component diffusivity. The objective of this study is to develop an optimal control framework to determine multi-component concentration-dependent diffusivities of two gases in a non-volatile phase such as polymer. In Part 1 of this study, we derived a detailed mass-transfer model of the experimental diffusion process for the non-volatile phase to provide the temporal masses of gases in the polymer. The determination of diffusivities is an inverse problem involving principles of optimal control. Necessary conditions are determined to solve this problem. In Part 2 of this study, we utilized the results of Part 1 to determine the concentration-dependent, multi-component diffusivities of nitrogen and carbon dioxide in polystyrene. To that end, solubility and diffusion experiments are conducted to obtain necessary data. In the ternary system of nitrogen (1), carbon dioxide (2), and polystyrene (3), the diffusivities and D11, D12, D21, and D22 versus the gas mass fractions are two-dimensional surfaces. The diffusivity of carbon dioxide was found to be greater than that of nitrogen. The value of the main diffusion coefficient D11 was found to increase as the concentration of carbon dioxide increased. The highest value of D11 obtained was 2.2 X 10^-8m^2s^-1 for nitrogen mass fraction of 3.14 X10^-4 and for a carbon dioxide mass fraction of 5.67 X 10^-4 . The cross-diffusion coefficient increased as the concentrations of nitrogen and carbon dioxide increased. The diffusivity reached its maximum value when the concentrations of nitrogen and carbon dioxide were at their maximum values. The diffusivity was of the order of 10^-9m^2s^-1. The diffusivity of the cross-diffusion coefficient D21 was found to be increased for the mass The diffusivity of the cross-diffusion coefficient was found to be increased for the mass fractions of carbon dioxide ranging from 0 to 1.70 X 10^-3 . The diffusivity was found to be of the order of . The diffusion coefficient, D22, was found to increase with the concentrations of nitrogen and carbon dioxide, D22 remained high with low concentrations of carbon dioxide. The diffusivity was found to be of the order of 10^-7m^2s^-1

Herein, we report the incorporation of a 10 μm thick reduced graphene oxide (RGO) barrier layer in a plasticized poly(vinyl chloride) (PVC) film as the main constituent in ion-selective membranes used in potentiometric solid-contact ion-selective electrodes (SCISE). Fourier transform infrared attenuated total reflection (FTIR-ATR) and oxygen transmission rate (OTR) measurements showed that the embedded RGO barrier efficiently impedes the diffusion of liquid water, carbon dioxide and oxygen (O2) through the 400 μm thick PVC film, which causes potential instability and irreproducibility of the SCISEs. The measurements revealed that the RGO layer completely blocks the carbon dioxide diffusion, while it fully blocks the water diffusion for 16 h and reduced the OTR by 85% on average. The μm-thick RGO films used in this study were easier to handle and incorporate into host polymers, and form more efficient and robust barriers compared to the mono-, few- and multilayer graphene commonly applied as barrier layers for liquids and gases. We also demonstrated that the FTIR-ATR technique employed in the permeability measurements is a versatile and very sensitive technique for studying the diffusion of small amounts of water and carbon dioxide through graphene-based thin films.

Plants can survive without oxygen in their atmospheres only if they have enough area of green tissue to produce free oxygen through the decomposition of the carbon dioxide that they form entirely from their own tissues. Oxygen seems to aid photosynthetic assimilation of carbon dioxide. Thus, in environments lacking oxygen, the elaboration of a certain amount of oxygen appears necessary for the decomposition of a certain amount of carbon dioxide. If the oxygen is removed as it is formed, plant growth is arrested. Seeds will not germinate in oxygen-free environments, and newly germinated seeds, before they have developed green parts, will die in these environments. Plants do not assimilate nitrogen, hydrogen, or carbon monoxide gases. They survive in these gases as they do in a vacuum, by means of the oxygen released by their leaves, and they can do so only if they are not in direct sunlight. The amount of oxygen needed to sustain a plant's life is small; more is needed for growth. Carbon dioxide always becomes harmful to plants if it is present in amounts too large for them to decompose. Excess carbon dioxide is more harmful to plants in an atmosphere of nitrogen than in one of ordinary air. In pure hydrogen gas, the carbon dioxide formed by the leaf from its own substance is decomposed by the hydrogen, with production of water and carbon monoxide gas. In an atmosphere of carbon monoxide, green plants, in the sun, do not decompose this gas but do add oxygen.

Adolf Fick (1829-1901), physiologist: a heritage for anesthesiology and critical care medicine.

Univariate diffusion of oxygen and carbon dioxide through a selective membrane of a stationary membranous oxygenator (SMO) and moving blood film is considered. Through the use of a precise exponential approximation of the oxyhemoglobin dissociation curve [S (p)=1--ae-bp] a partial oxygen pressure distribution [p (x)] along the SMO membrane and a transcedental equation for estimating the value for partial pressure (pa) of the arterialized blood and the SMO efficiency with reference to oxygen have been obtained. A somewhat less exact logarithmic approximation of the summary blood oxygen concentration [C1=a1+b1ln(p--po)] enables it to arrive at an analytical expression for calculating the SMO efficiency with reference to oxygen in a positively definite form. On the other hand, by using logarithmic approximation of the summary carbon dioxide concentration proceeding from the partial CO2 pressure in the blood a partial CO2 pressure distribution along the membrane, as well as an analytical expression for estimating the SMO efficiency with reference to carbon dioxide could be obtained.

Chapter 9 - Flow in the Lungs