Study on Electric Strength and Synergistic Effect of C3F7CN-CO2 Gas Mixture by Steady State Townsend Method

A small portable chamber for the recovery of anaerobic bacteria is described. This rigid chamber is constructed of clear acrylic with dimensions of 30 inches (ca. 76.2 cm) wide, 18 inches (ca. 44.7 cm) deep, and 18 inches (ca. 44.7 cm) high. Conventional bacteriological techniques can be used inside the chamber to efficiently isolate strict anaerobic organisms. An adapter allows the attachment of a standard anaerobic jar to the outside of the chamber. The jar can be used to store reduced media. Once the jar is attached to the chamber and the media is removed to the interior of the chamber, the jar is available to receive inoculated media. The anaerobic jar can then be removed from the chamber, without contaminating the jar or chamber with oxygen, and be placed in a conventional 37degreesC incubator. This chamber also allows the microbiologist to process cultures without wearing gloves as was necessary with previous anaerobic chambers. Air-tight latex rubber sleeves seal around the microbiologists arms and to the armport flange of the chamber to prevent the introduction of oxygen into the chamber. Anaerobic conditions are maintained by circulating a 80% N2, 10% H2, 10% CO2 gas mixture through alumina pellets coated with palladium. This study indicates that anaerobic conditions obtained in this chamber are sufficient for recovery of obligate anaerobes.

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Investigation of N2-Composition in CO2 Gas Mixture for EOR Purpose

Saint Petersburg 2018 ◽

10.3997/2214-4609.201800139 ◽

2018 ◽

Author(s):

E. Ghanaatpisheh Senani ◽

H. Behmanesh ◽

S. Kord ◽

S. Bairamzadeh

Keyword(s):

Gas Mixture ◽

Co2 Gas

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AC Volume Breakdown and Surface Flashover of a 4% NovecTM 4710/96% CO2 Gas Mixture Compared to CO2 in Highly Nonhomogeneous Fields

Energies ◽

10.3390/en13071710 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1710 ◽

Cited By ~ 1

Author(s):

Houssem Eddine Nechmi ◽

Mohammed El Amine Slama ◽

Abderrahmane (Manu) Haddad ◽

Gordon Wilson

Keyword(s):

Electrical Strength ◽

Gas Mixture ◽

Nonlinear Behaviour ◽

Co2 Gas ◽

Surface Flashover ◽

Surface Finishes ◽

Needle Position ◽

Flashover Voltage ◽

Solid Insulator ◽

Solid Dielectrics

AC pre-discharge currents, breakdown, and flashover voltage measurements are reported in a 10 mm needle-plane arrangement in a 4% NovecTM 4710/96% CO2 gas mixture and compared with CO2 for pressures up to 8.8 bar abs. Flashover measurements were performed on different solid dielectrics (Al2O3_filled epoxy resins, PTFE (Polytetrafluoroethylene) and PE (polyethylene)) for different roughness surface finishes. The effect of fixed conducting needles at various positions on electrical strength is reported. A strong nonlinear behaviour as function of gas pressure was observed for all the studied parameters (gas, needle position, solid insulator, insulator roughness). The non-linear behaviour is attributed to the inception and quenching of glow corona, in the interval between inception and breakdown or flashover voltages. It is found that a 4% concentration of NovecTM 4710 in CO2 has a breakdown/flashover voltage ≈ 1.14 higher than CO2. The glow corona-induced stabilization effect is seen for pressures between 2 and 5 bar abs for all the studied parameters. The peak flashover voltage and its associated pressure of the different insulators are strongly dependent on surface roughness. At 8.8 bar abs, the flashover voltage level obtained with various materials was ordered as follows: PTFE > PE-UHMW > Epoxy > HDPE(High-density polyethylene).

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Effects of N2O narcosis on breathing and effort sensations during exercise and inspiratory resistive loading

Journal of Applied Physiology ◽

10.1152/jappl.1996.81.4.1562 ◽

1996 ◽

Vol 81 (4) ◽

pp. 1562-1571 ◽

Cited By ~ 4

Author(s):

D. M. Fothergill ◽

N. A. Carlson

Keyword(s):

Heart Rate ◽

Steady State ◽

Minute Ventilation ◽

Esophageal Pressure ◽

Incremental Exercise ◽

Time To Exhaustion ◽

Gas Mixture ◽

Resistive Loading ◽

Inspiratory Resistance ◽

Sufficient Magnitude

Fothergill, D. M., and N. A. Carlson. Effects of N2O narcosis on breathing and effort sensations during exercise and inspiratory resistive loading. J. Appl. Physiol. 81(4): 1562–1571, 1996.—The influence of nitrous oxide (N2O) narcosis on the responses to exercise and inspiratory resistive loading was studied in thirteen male US Navy divers. Each diver performed an incremental bicycle exercise test at 1 ATA to volitional exhaustion while breathing a 23% N2O gas mixture and a nonnarcotic gas of the same [Formula: see text], density, and viscosity. The same gas mixtures were used during four subsequent 30-min steady-state submaximal exercise trials in which the subjects breathed the mixtures both with and without an inspiratory resistance (5.5 vs. 1.1 cmH2O ⋅ s ⋅ l−1at 1 l/s). Throughout each test, subjective ratings of respiratory effort (RE), leg exertion, and narcosis were obtained with a category-ratio scale. The level of narcosis was rated between slight and moderate for the N2O mixture but showed great individual variation. Perceived leg exertion and the time to exhaustion were not significantly different with the two breathing mixtures. Heart rate was unaffected by the gas mixture and inspiratory resistance at rest and during steady-state exercise but was significantly lower with the N2O mixture during incremental exercise ( P< 0.05). Despite significant increases in inspiratory occlusion pressure (13%; P < 0.05), esophageal pressure (12%; P < 0.001), expired minute ventilation (4%; P < 0.01), and the work rate of breathing (15%; P < 0.001) when the subjects breathed the N2O mixture, RE during both steady-state and incremental exercise was 25% lower with the narcotic gas than with the nonnarcotic mixture ( P < 0.05). We conclude that the narcotic-mediated changes in ventilation, heart rate, and RE induced by 23% N2O are not of sufficient magnitude to influence exercise tolerance at surface pressure. Furthermore, the load-compensating respiratory reflexes responsible for maintaining ventilation during resistive breathing are not depressed by N2O narcosis.

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Experimental Study on Power Frequency Breakdown Characteristics of C4F7N/CO2 Gas Mixture Under Quasi-Homogeneous Electric Field

IEEE Access ◽

10.1109/access.2019.2897749 ◽

2019 ◽

Vol 7 ◽

pp. 19100-19108 ◽

Cited By ~ 10

Author(s):

Xiaoxing Zhang ◽

Qi Chen ◽

Ji Zhang ◽

Yi Li ◽

Song Xiao ◽

...

Keyword(s):

Experimental Study ◽

Electric Field ◽

Gas Mixture ◽

Homogeneous Electric Field ◽

Co2 Gas ◽

Power Frequency

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ENDOTHELIUM-INDEPENDENT PARTIAL AGONISTIC ACTIVITY OF VASOPRESSIN IN THE RAT COMMON CAROTID ARTERY

10.1055/s-0038-1644600 ◽

1987 ◽

Author(s):

Z S Katušić ◽

M K Krstić

Keyword(s):

Carotid Artery ◽

Common Carotid Artery ◽

Contact Time ◽

Partial Agonist ◽

Isometric Tension ◽

Gas Mixture ◽

Peripheral Arteries ◽

Co2 Gas ◽

Canine Basilar Artery ◽

Agonistic Activity

It has been shown that vasopressin causes endothelium-dependent relaxations of the canine basilar artery, suggesting that_increased circulating concentrations of vasopressin can produce redistribution of the blood from the peripheral to the cerebral circulation (Katušić et al., 1984). The present experiments were done to examine effect of vasopressin on the rat peripheral arteries* The experiments were performed on rings (4 mm long) of aorta, common carotid and renal arteries* The arteries were placed in Krebs-Ringer-bicarbonate solution gassed with 95%O2-5%co2 gas mixture and kept at 37°c. In certain rings the endothelium was removed mechanically by gentle rubbing of the intimal surface. Isometric tension was continously recorded (IPM electronic).Vasopressin (10-11 to 3×10-8 M) caused concentration-dependent contraction being full agonist in aorta and renal artery, but partial agonist in common carotid artery. After removal of endothelium vasopressin-induced contractions were not significantlly afected in any of the tested arteries. Gyclooxygenase inhibitor indomethacin (10-5 M; contact time = 40 min) did not affect partial agonistic activity of vasopressin in common carotid artery. This results indicate that partial agonistic activity of vasopressin in common carotid artery is not related to increased production of "EDRF" or prostacyclin from endothelium. In addition, our findings are consistent with the hypothesis that vasopressin may contribute to redistribution of the blood flow from the peripheral to the cerbral circulation.Z.S. Katušić, J.T. Shepherd and P.M. Vanhoutte. Circ. Res., 55: 575-579, 1984

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The thermal conductivity of gas mixtures

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1929.0060 ◽

1929 ◽

Vol 123 (791) ◽

pp. 134-142 ◽

Cited By ~ 29

Keyword(s):

Thermal Conductivity ◽

Steady State ◽

Calibration Curve ◽

Bridge Circuit ◽

Simple Calculation ◽

Gas Analysis ◽

Heat Losses ◽

Gas Mixture ◽

Metallic Conduction ◽

Copper Lead

The action of the katharometer as an instrument for gas analysis depends essentially upon the thermal conductivity of the gas mixture examined. One method of calibration for a given pair of gases is to make a number of mixtures of known composition by volume, and to obtain from them a curve showing how the deflection θ of the galvanometer in the bridge circuit of the instrument depends upon the composition of the mixture which surrounds one of the fine platinum helices. By reference to this curve, any other mixture of the two gases can be analysed when its deflection is known. A typical calibration curve is shown in fig. 1, which is for mixtures of helium and argon. The direction of the galvanometer deflection depends on whether the gas is a better or worse conductor than air. A useful convention is to regard the deflection for gases which are better conductors than air as positive. Daynes has examined the nature of the heat losses in the katharometer cell, which are due to ( a ) radiation, ( b ) convection, ( c ) conduction by the gas, ( d ) cooling of the platinum helix by metallic conduction along the copper lead. Even at the highest temperature used in the katharometer, the effect of ( a ) is very small, and will not be influenced directly by the nature of the gas surrounding the wire. Experiments have shown that the effect of ( b ) is also small. The effect of ( c ) on the temperature of the helix is large, and will depend upon the nature of the gas. The effect of ( d ) is also considerable, and will depend upon the temperature of the helix. This effect will consequently vary with the nature of the gas under examination, but the magnitude of the effect in the steady state which is reached depends upon the effect of ( c ) (the small effects of convection and radiation will similarly depend upon the effect of ( c )). Thus in practice, the thermal conductivity of the gas controls the temperature of the helix, and the instrument will give the same reading for all gases or mixtures having the same thermal conductivity. Owing to the complicated design of the katharometer cell, it is not possible to make a simple calculation of the heat loss due solely to the conductivity of the gas, or to devise a method of converting katharometer readings directly into thermal conductivities. It should be noticed also that the calibration curves for different instruments are not all of quite the same form, owing to small differences in the winding of the helix, or of its position in the cell.

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Effect of upper airway CO2 on breathing in awake ponies

Journal of Applied Physiology ◽

10.1152/jappl.1985.59.4.1222 ◽

1985 ◽

Vol 59 (4) ◽

pp. 1222-1227 ◽

Cited By ~ 3

Author(s):

H. V. Forster ◽

L. G. Pan ◽

C. Flynn ◽

G. E. Bisgard ◽

R. E. Hoffer

Keyword(s):

Endotracheal Tube ◽

Environmental Temperature ◽

Upper Airway ◽

Gas Mixture ◽

Upper Airways ◽

Co2 Gas ◽

Arterial Pco2 ◽

Cuffed Endotracheal Tube ◽

Breathing Room ◽

Sensory Mechanism

We determined whether the [CO2] in the upper airways (UA) can influence breathing in ponies and whether UA [CO2] contributes to the attenuation of a thermal tachypnea during periods of elevated inspired CO2. Six ponies were studied 1 mo after chronic tracheostomies were created. For one protocol the ponies were breathing room air through a cuffed endotracheal tube. Another smaller tube was placed in the tracheostomy and directed up the airway. By use of this tube, a pump, and prepared gas mixtures, UA [CO2] was altered without affecting alveolar or arterial PCO2. When the ponies were at a neutral environmental temperature (TA) and breathing frequency (f) was 8 breaths X min-1, increasing UA [CO2] up to 18–20% had no effect on f. However, when TA was increased 20 degrees C to increase f to 50 breaths X min-1, then increasing UA [CO2] to 6% or to 18–20% reduced f by 5 +/- 1.7 (SE) and 12 +/- 1.6 breaths X min-1, respectively (t = 3.3, P less than 0.01). These data suggest that in the pony there exists a UA CO2-H+ sensory mechanism. For a second protocol the ponies were breathing a 6% CO2 gas mixture for 15 min in the normal fashion over the entire airway (nares breathing, NBr) or they were breathing this gas mixture for 15 min through the cuffed endotracheal tube (TBr). At a neutral TA, increasing inspired [CO2] to 6% resulted in a 6-breaths X min-1 increase in f during both NBr and TBr.

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