The independent effects of atmospheric pressure and oxygen partial pressure on gas exchange of the chicken embryo

1980 ◽  
Vol 39 (1) ◽  
pp. 33-44 ◽  
Author(s):  
A.H.J. Visschedijk ◽  
A. Ar ◽  
H. Rahn ◽  
J. Piiper
Keyword(s):  
Gas Exchange ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Atmospheric Pressure ◽  
Chicken Embryo ◽  
Independent Effects

Preliminary evaluation of a predictive controller for a rotary blood pump based on pulmonary oxygen gas exchange

2019 ◽  
Vol 233 (2) ◽  
pp. 267-278 ◽  
Author(s):  
Feng Huang ◽  
Zhe Gou ◽  
Yang Fu
Keyword(s):  
Gas Exchange ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Left Ventricular ◽  
Blood Pump ◽  
Rotary Blood Pump ◽  
Blood Pumps ◽  
Control Objective ◽  
Predictive Controller ◽  
Rotary Blood Pumps

Physiological control of rotary blood pumps is becoming increasingly necessary for clinical use. In this study, the mean oxygen partial pressure in the upper airway was first quantitatively evaluated as a control objective for a rotary blood pump. A model-free predictive controller was designed based on this control objective. Then, the quantitative evaluation of the controller was implemented with a rotary blood pump model on a complete cardiovascular model incorporated with airway mechanics and gas exchange models. The results show that the controller maintained a mean oxygen partial pressure at a normal and constant level of 138 mmHg in the left heart failure condition and restored basic haemodynamics of blood circulation. A left ventricular contractility recovery condition was also replicated to assess the response of the controller, and a stable result was obtained. This study indicates the potential use of the oxygen partial pressure index during pulmonary gas exchange when developing a multi-objective physiological controller for rotary blood pumps.

scholarly journals Higher propene yield by tailoring operating conditions of propane oxidative dehydrogenation over V2O5/γ-Al2O3

2015 ◽  
Vol 80 (3) ◽  
pp. 355-366 ◽  
Author(s):  
Yousef Zaynali ◽  
Seyed Alavi
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxidative Dehydrogenation ◽  
Atmospheric Pressure ◽  
Operating Conditions ◽  
Propane Conversion ◽  
Propane Oxidative Dehydrogenation ◽  
Wet Impregnation ◽  
Vanadia Catalyst ◽  
Oxygen Ratio

Supported vanadia catalyst was successfully synthesized using wet impregnation of ?-Alumina to study Propane Oxidative Dehydrogenation (POD). The prepared catalysts were characterized with XRD, BET, and TPR tests. In a broad temperature range (340 to 630?C), effects of vanadia loading (2.7, 5.4, and 9 wt%) and propane to oxygen ratio (3/1 to 1/3) were thoroughly investigated on propane conversion as well as propene yield at atmospheric pressure. Results indicate that by increasing the vanadia content the activity of catalyst increases while selectivity to propene decreases monotonically. As the temperature increases from 340?C to 630?C, yield to propene shows ascending behavior in case of all catalyst samples. Yield to propene shows a climax with changing propane to oxygen ratio from 3/1 to 1/3. The yield increases with increase in oxygen partial pressure of feed until equimolar ratio of propane and oxygen, then it declines with further increase of oxygen partial pressure. A maximum propene yield of 17% was experienced on catalyst with 2.7wt% vanadia at temperatures at 550?C.

The Effects of Oxygen Vacancy Concentration on the Mechanical Properties of Zirconia and Ceria-Based Electrolytes for SOFCs

2009 ◽  
Author(s):  
Toshiyuki Hashida ◽  
Yohei Takeyama ◽  
Kazuhisa Sato
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Fracture Surface ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Fracture Strength ◽  
Atmospheric Pressure ◽  
Small Punch ◽  
Testing Method ◽  
Partial Pressures

In this paper, we discuss the effects of different oxygen partial pressures on the deformation property and fracture characteristics of representative constituent materials for solid oxide fuel cells (SOFCs). The elastic modulus and fracture strength of 8 mol% yittria stabilized zirconia (8YSZ) and 10 mol% gadolinia doped ceria (10GDC) treated under different oxygen partial pressures were evaluated using the small-punch testing method in this study. The specimens of 8YSZ and 10GDC prepared by a sintering process were treated at 800 °C under an oxygen partial pressure in the range of 0.21 to 10−22 atm for 1 hour. The treated specimens were then fast cooled down to a room temperature, and their mechanical properties were measured under an atmospheric pressure condition by using the small-punch testing method. The experimental results revealed that both the elastic modulus and fracture strength of the 10GDC decreased drastically when the oxygen partial pressure of the treatment was less than 10−15 atm, whereas no significant variation in both the mechanical properties was observed for the 8YSZ. The elastic modulus and fracture strength of 10GDC for the treatment under 10−22 atm was reduced down to 10–20% of those treated under the atmospheric pressure. SEM observations revealed that the fracture surface of the 10GDC specimens was changed from transgranular mode to intergranular mode when the oxygen partial pressure was reduced, whereas the fracture surface of the 8YSZ specimens was transgranular regardless of the different oxygen partial pressures.

Comparison of the Ablation Mechanism of C/C-SiC Composite under Atmospheric and Low Pressure

2014 ◽  
Vol 91 ◽  
pp. 134-139 ◽  
Author(s):  
Roberson J. Silva ◽  
Homero S. Maciel ◽  
Alexei M. Essiptchouk ◽  
Gilberto Petraconi
Keyword(s):  
Surface Temperature ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Atmospheric Pressure ◽  
Thermal Protection ◽  
Sample Surface ◽  
Low Pressure ◽  
Protective Oxide ◽  
Maximum Surface ◽  
Maximum Surface Temperature

Comparisons of heating tests at atmospheric pressure and low pressure by using a thermal plasma torch were performed. A constant heat flux on the sample surface was applied in the study of the oxidation mechanism of C/C-SiC composite, used in thermal protection systems. The SEM and EDS analysis show an intensive glassification at the surface, which are strongly depend on the oxygen partial pressure and the sample surface temperature. For vacuum conditions, at maximum surface temperature of 1450 °C and the oxygen partial pressure of about 66 Pa, a uniform passivation layer of SiO2 is formed. At atmospheric pressure, under an oxygen partial pressure of 2.1×104 Pa, the maximum surface temperature is 400 °C higher than obtained in vacuum, reaching levels of 1850°C. Under these conditions, the protective oxide layer is partially volatilized with time, increasing the specific mass loss rate by a sublimation of the composite, directly exposed to the plasma jet. This effect is alike to what occurs in the process of transition from passive to active oxidation of SiC.

High Crystalline Cu2O Thin Films Prepared by Electric Current Heating Using Copper Wire

2014 ◽  
Vol 90 ◽  
pp. 66-71
Author(s):  
Tomoichiro Okamoto ◽  
Ko Yamazaki ◽  
Yuichiro Kuroki ◽  
Masasuke Takata
Keyword(s):  
Thin Films ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Electric Current ◽  
Atmospheric Pressure ◽  
Copper Wire ◽  
Time Response ◽  
Controlled Atmosphere ◽  
Electric Currents ◽  
Glass Substrates

Cu wires were heated by electric currents to fabricate Cu2O thin films. The films were successfully deposited on glass substrates placed above the wires at air pressures in the range of 100 - 40 Pa. Then the films were annealed in a controlled atmosphere and investigated the crystallinity, morphology and the time response to illumination of the films. After annealing at 800 °C at atmospheric pressure with oxygen partial pressure of 12 Pa, the crystallinity was increased and the time response of photoconduction was successfully improved.

Respiratory gases in uterine circulation of pregnant domestic swine as sampled by indwelling catheters

1978 ◽  
Vol 234 (1) ◽  
pp. R25-R28 ◽  
Author(s):  
D. Caton ◽  
F. W. Bazer
Keyword(s):  
Gas Exchange ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Significant Relationship ◽  
Venous Blood ◽  
Mean Value ◽  
Indwelling Catheters ◽  
Respiratory Gases ◽  
Uterine Circulation ◽  
Domestic Swine

Data dealing with placental respiratory gas exchange are scant for species with an epitheliochorial placenta. None have been obtained from awake, unstressed animals. For this reason 18 pregnant swine were prepared with chronically implanted polyvinyl catheters. Respiratory gases in arterial and uterine venous blood were observed between the 30th day of gestation and term (110 days). There was a statistically significant relationship between uterine venous oxygen partial pressure (Po2 and the day of gestation. The value for Po2, fell from a mean of 70 to 57 Torr. The latter appears to be the highest mean value yet observed in uterine vein of any species at term. pregnancy; chronic preparation Submitted on March 7, 1977

Augmented respiration in a flying insect

1998 ◽  
Vol 201 (16) ◽  
pp. 2359-2366 ◽  
Author(s):  
Y Komai
Keyword(s):  
Gas Exchange ◽  
Stroke Volume ◽  
Metabolic Rate ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Sweet Potato ◽  
Longitudinal Muscle ◽  
Tethered Flight ◽  
Positional Angle ◽  
The Mean

The properties of the gas transport system in a tethered flying insect were investigated by directly measuring the oxygen partial pressure (PO2) in a wing muscle of the sweet potato hawkmoth Agrius convolvuli using a needle electrode. At rest, a distribution of PO2 corresponding to levels in the muscle and tracheal structures was observed. At the onset of tethered flight, PO2 in the muscle decreased. However, during a long stable flight, PO2 increased and reached a plateau approximately 2 min after the onset of flight. During stable tethered flight, PO2 in the centre of the second layer of the dorsal longitudinal muscle was locally higher than that during rest. As wing amplitude increased, PO2 increased in spite of the concurrent increase in metabolic rate. During tethered flight at a constant wing amplitude, PO2 was proportional to the mean wing positional angle. The results suggest that this insect effectively uses muscle movement, which increases the frequency and stroke volume of ventilation, to augment gas exchange during flight.

scholarly journals The relative distribution of pulmocutaneous blood flow in Rana catesbeiana: effects of pulmonary or cutaneous hypoxia

1986 ◽  
Vol 126 (1) ◽  
pp. 33-39 ◽  
Author(s):  
R. G. Boutilier ◽  
M. L. Glass ◽  
N. Heisler
Keyword(s):  
Blood Flow ◽  
Gas Exchange ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Rana Catesbeiana ◽  
The Body ◽  
Relative Distribution ◽  
Low Oxygen ◽  
Exchange Site ◽  
Environmental Air

The distribution of pulmocutaneous heart output to lungs and skin was determined in non-anaesthetized, fully recovered bullfrogs (Rana catesbeiana) by application of the microsphere method in order to study the modulation of blood flow to different gas exchange sites in amphibians during environmental air and water hypoxia. The relative perfusion of various skin areas was found to be rather heterogeneously distributed with an over-proportionately high blood flow to the ventral body surface. This distribution of flow among different skin areas remained unaffected by any type of environmental hypoxia. The relative perfusion of lungs and skin, however, was significantly affected by the pattern of environmental oxygen partial pressure. The relative lung perfusion (approximately equal to 80% of pulmocutaneous flow in normoxic control conditions) was increased during water hypoxia, and reduced with lowered inspired PO2. This mechanism could be interpreted as a readjustment of blood flow towards the gas exchange site with higher oxygen partial pressure, but may also represent a mechanism to prevent oxygen loss from the body stores at gas exchange sites of low oxygen tension.

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