scholarly journals Non-obvious Problems in Clark Electrode Application at Elevated Temperature and Ways of Their Elimination

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
M. V. Miniaev ◽  
M. B. Belyakova ◽  
N. V. Kostiuk ◽  
D. V. Leshchenko ◽  
T. A. Fedotova
Keyword(s):  
Gas Phase ◽  
Oxygen Sensor ◽  
Gas Bubbles ◽  
Oxygen Sensors ◽  
Measuring System ◽  
Dissolved Gases ◽  
Spontaneous Release ◽  
Complete Exclusion ◽  
Typical Temperature ◽  
Clark Electrode

Well-known cause of frequent failures of closed oxygen sensors is the appearance of gas bubbles in the electrolyte. The problem is traditionally associated with insufficient sealing of the sensor that is not always true. Study of a typical temperature regime of measurement system based on Clark sensor showed that spontaneous release of the gas phase is a natural effect caused by periodic warming of the sensor to a temperature of the test liquid. The warming of the sensor together with the incubation medium causes oversaturation of electrolyte by dissolved gases and the allocation of gas bubbles. The lower rate of sensor heating in comparison with the medium reduces but does not eliminate the manifestation of this effect. It is experimentally established, that with each cycle of heating of measuring system up to 37°C followed by cooling the volume of gas phase in the electrolyte (KCl; 60 g/L; 400 μL) increased by 0.6 μL approximately. Thus, during just several cycles it can dramatically degrade the characteristics of the sensor. A method was developed in which the oxygen sensor is heated in contact with the liquid, (depleted of dissolved gases), allowing complete exclusion of the above-mentioned effect.

SINKAGE STUDIES. III. CHANGES IN THE WATER-GAS SYSTEM IN LOGS DURING SEASONING AND FLOTATION

1930 ◽  
Vol 3 (1) ◽  
pp. 80-93
Author(s):  
G. W. Scarth ◽  
R. Darnley Gibbs
Keyword(s):  
Carbon Dioxide ◽  
Gas Phase ◽  
Gas Bubbles ◽  
Dissolved Gases ◽  
Laboratory Conditions ◽  
Evaporation Loss ◽  
Gas System ◽  
Water Gas ◽  
A Current

Under laboratory conditions a very large fermentative evolution of carbon dioxide takes place in logs during both seasoning and flotation, increasing their gas phase and their buoyancy. The principal changes which take place in the water-gas system of logs during seasoning and flotation have been followed by weight measurements and analyses showing water distribution.End penetration has been shown to be an important factor in sinkage, at any rate when evaporation from the upper surface of the log is considerable. Bolts, 2 ft. 8 in. long gained, during flotation for 8 months, from two to three times as much water when their ends were unpainted as when they were painted. End penetration, combined with evaporation, was found to create through the log a current of water which helps to transport dissolved gases, and to reduce the volume of the gas bubbles held in the cells. It thus acts doubly towards reducing buoyancy by replacing evaporation loss and by facilitating the escape of the imprisoned gases.

scholarly journals The impact of particulate electron paramagnetic resonance oxygen sensors on fluorodeoxyglucose imaging characteristics detected via positron emission tomography

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philip E. Schaner ◽  
Ly-Binh-An Tran ◽  
Bassem I. Zaki ◽  
Harold M. Swartz ◽  
Eugene Demidenko ◽  
...  
Keyword(s):  
Fdg Pet ◽  
Oxygen Sensor ◽  
Oxygen Sensors ◽  
Paramagnetic Resonance ◽  
Imaging Characteristics ◽  
Positron Emission ◽  
Pet Ct ◽  
Fdg Pet Ct ◽  
The Impact ◽  
Electron Paramagnetic

AbstractDuring a first-in-humans clinical trial investigating electron paramagnetic resonance tumor oximetry, a patient injected with the particulate oxygen sensor Printex ink was found to have unexpected fluorodeoxyglucose (FDG) uptake in a dermal nodule via positron emission tomography (PET). This nodule co-localized with the Printex ink injection; biopsy of the area, due to concern for malignancy, revealed findings consistent with ink and an associated inflammatory reaction. Investigations were subsequently performed to assess the impact of oxygen sensors on FDG-PET/CT imaging. A retrospective analysis of three clinical tumor oximetry trials involving two oxygen sensors (charcoal particulates and LiNc-BuO microcrystals) in 22 patients was performed to evaluate FDG imaging characteristics. The impact of clinically used oxygen sensors (carbon black, charcoal particulates, LiNc-BuO microcrystals) on FDG-PET/CT imaging after implantation in rat muscle (n = 12) was investigated. The retrospective review revealed no other patients with FDG avidity associated with particulate sensors. The preclinical investigation found no injected oxygen sensor whose mean standard uptake values differed significantly from sham injections. The risk of a false-positive FDG-PET/CT scan due to oxygen sensors appears low. However, in the right clinical context the potential exists that an associated inflammatory reaction may confound interpretation.

The crystallization of the teschenite from the Lugar Sill, Ayrshire

1968 ◽  
Vol 105 (1) ◽  
pp. 23-34 ◽  
Author(s):  
W. J. Phillips
Keyword(s):  
Gas Phase ◽  
Vapour Pressure ◽  
Gas Bubbles

SUMMARYTwelve stages in the crystallization of the teschenite are defined by the commencement or cessation of crystallization of particular minerals. Ocellar structures, outlined by tangentially arranged biotite flakes, developed in liquid pockets after the sill had begun to consolidate, due to the coalescence of crystalline masses. It is thought that these ocellar structures were formed by the growth of gas bubbles and that this caused the expansion and fracturing of the partially consolidated sill. It is argued that the separation of the gas phase was the result of a retrograde increase in the vapour pressure during crystallization.

Oxygen Sensor Testing for Automotive Applications

2020 ◽  
Vol 896 ◽  
pp. 249-254
Author(s):  
Dragos Tutunea ◽  
Ilie Dumitru ◽  
Oana Victoria Oţăt ◽  
Laurentiu Racila ◽  
Ionuţ Daniel Geonea ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Oxygen Sensor ◽  
Oxygen Sensors ◽  
Pollutant Emissions ◽  
Combustion Engines ◽  
Automotive Applications ◽  
Combustion Gases ◽  
Experimental Stand ◽  
Residual Oxygen ◽  
Sensor Degradation

During the operation of internal combustion engines the air-fuel ratio (A/F) is an important parameter which affects fuel consumption and pollutant emissions. The automotive oxygen sensor (Lambda) measures the quantity of residual oxygen in the combustion gases. Sensor degradation in time due to the exposure to high temperatures causes a distortion in controlling the A/F with the increase in gas emissions. In this paper an experimental stand is designed to test oxygen sensor degradation in laboratory condition. Four oxygen sensors were tested function of temperature and time recording their variation in resistance and voltage. The results showed similar values in the curves for all sensors tested.

A highly sensitive and fast-responding oxygen sensor based on POSS-containing hybrid copolymer films

2017 ◽  
Vol 5 (44) ◽  
pp. 11395-11402 ◽  
Author(s):  
Yongyun Mao ◽  
Qian Zhao ◽  
Jianchang Wu ◽  
Tingting Pan ◽  
Bingpu Zhou ◽  
...  
Keyword(s):  
High Performance ◽  
Oxygen Sensor ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Oxygen Sensors ◽  
Inorganic Hybrid ◽  
Copolymer Films ◽  
Hybrid Copolymer ◽  
Highly Sensitive ◽  
Platinum Porphyrin ◽  
Oligomeric Silsesquioxane

Organic–inorganic hybrid 3-(trimethoxysily)propylmethacrylate-co-platinum porphyrin-co-methacrylolsobutyl-polyhedral oligomeric silsesquioxane (TPMA-PtTPP-POSS) copolymer films were synthesized and applied as high-performance oxygen sensors.

scholarly journals Evaluation of Gas Phase Dispersion in Flotation under Predetermined Hydrodynamic Conditions

2018 ◽  
Vol 35 ◽  
pp. 01011
Author(s):  
Anna Młynarczykowska ◽  
Konrad Oleksik ◽  
Klaudia Tupek-Murowany
Keyword(s):  
Gas Phase ◽  
Gas Bubbles ◽  
Random Variable ◽  
Raw Material ◽  
Particle Collision ◽  
Hydrodynamic Conditions ◽  
Flotation Process ◽  
Phase Dispersion ◽  
Specific Distribution ◽  
Instrumental Methods

Results of various investigations shows the relationship between the flotation parameters and gas distribution in a flotation cell. The size of gas bubbles is a random variable with a specific distribution. The analysis of this distribution is useful to make mathematical description of the flotation process. The flotation process depends on many variable factors. These are mainly occurrences like collision of single particle with gas bubble, adhesion of particle to the surface of bubble and detachment process. These factors are characterized by randomness. Because of that it is only possible to talk about the probability of occurence of one of these events which directly affects the speed of the process, thus a constant speed of flotation process. Probability of the bubble-particle collision in the flotation chamber with mechanical pulp agitation depends on the surface tension of the solution, air consumption, degree of pul aeration, energy dissipation and average feed particle size. Appropriate identification and description of the parameters of the dispersion of gas bubbles helps to complete the analysis of the flotation process in a specific physicochemical conditions and hydrodynamic for any raw material. The article presents the results of measurements and analysis of the gas phase dispersion by the size distribution of air bubbles in a flotation chamber under fixed hydrodynamic conditions. The tests were carried out in the Laboratory of Instrumental Methods in Department of Environmental Engineering and Mineral Processing, Faculty of Mining and Geoengineerin, AGH Univeristy of Science and Technology in Krakow.

Synthesis of Perovskite Sr Doped Lanthanide Cobaltites and Ferrites and Application for Oxygen Sensors: A Comparative Study

2014 ◽  
Vol 605 ◽  
pp. 483-486 ◽  
Author(s):  
Katarina Cvejin ◽  
Libu Manjakkal ◽  
Jan Kulawik ◽  
Krzysztof Zaraska ◽  
Dorota Szwagierczak
Keyword(s):  
Oxygen Sensor ◽  
Elevated Temperatures ◽  
Solid State Reaction Method ◽  
Oxygen Sensors ◽  
Yttria Stabilized Zirconia ◽  
Electrochemical Cells ◽  
Stabilized Zirconia ◽  
Sensor Application ◽  
Oxygen Gas ◽  
Synthesized Materials

Perovskites with formula A1-xSrxBO3-δ (A = La, Nd, Sm; B = Fe or Co) have been synthesized by solid state reaction method and have been studied as materials for oxygen sensor application. The obtained powders were used for making thick film pastes that were later screen printed as sensing electrodes on yttria stabilized zirconia (YSZ) substrates. Sensing electrodes were exposed to low concentration oxygen gas at elevated temperatures. Measurements of the electromotive force of electrochemical cells with the fabricated electrodes were carried out as a function of temperature. The investigation indicated that all of the synthesized materials show Nernstian behavior in a relatively wide temperature range, although the most promising for oxygen electrochemical sensor application is strontium doped samarium cobaltite.

scholarly journals Study on calibration period of Gas Sensor in exercise Pulmonary Function instrument

2018 ◽  
Vol 2 (3) ◽  
pp. 66
Author(s):  
Jingxia Sun ◽  
Aimin Zhang ◽  
Guoqiang Gong ◽  
Jian Jiang
Keyword(s):  
Carbon Dioxide ◽  
Pulmonary Function ◽  
Oxygen Sensor ◽  
Matched Control ◽  
Oxygen Sensors ◽  
Control Group ◽  
Matched Control Group ◽  
Calibration Period ◽  
Carbon Dioxide Sensors ◽  
Carbon Dioxide Sensor

Objective: to study the calibration period of the main motor pulmonary function instrument sensor. Methods: A matched control group was used, one was calibrated periodically and the other was not calibrated. The calibration values of oxygen sensor and carbondioxide sensor were compared. Results: the oxygen sensor of electrochemical type was most sensitive to the change of time and environment, and the carbon dioxide sensor of infrared type was more sensitive to the change of time and environment. Conclusion: oxygen sensors of electrochemical type and carbon dioxide sensors of infrared type should be calibrated before each use.

Tissue window chamber system for validation of implanted oxygen sensors

2003 ◽  
Vol 284 (6) ◽  
pp. H2288-H2294 ◽  
Author(s):  
Milan T. Makale ◽  
Joe T. Lin ◽  
Richard E. Calou ◽  
Amy G. Tsai ◽  
Peter C. Chen ◽  
...  
Keyword(s):  
Oxygen Sensor ◽  
Sensor Arrays ◽  
Experimental System ◽  
Simultaneous Recording ◽  
Oxygen Sensors ◽  
Inhibitory Effects ◽  
Observation Window ◽  
Sensor Signals ◽  
Window Chamber ◽  
Electrochemical Oxygen

An experimental system is described for validating electrochemical oxygen sensors implanted in tissues. The system is a modified hamster window chamber in which a thin layer of vascularized tissue is held between two plates, one plate having an observation window and the other plate having an array of oxygen sensors. This arrangement permits simultaneous recording of oxygen sensor signals and nondestructive visualization of the tissue adjacent to the sensors over periods of 1 mo or more, without the inhibitory effects of anesthesia. The system provides a means for study of the effects of spatial and temporal oxygen distributions on the sensor signals and adaptation of the tissue structure over time. Examples are given of sensor recordings and images of tissues with implanted oxygen sensor arrays.

Process characteristics for a gas—liquid system agitated in a vessel equipped with a turbine impeller and tubular baffles

2011 ◽  
Vol 65 (2) ◽  
Author(s):  
Marta Major-Godlewska ◽  
Joanna Karcz
Keyword(s):  
Liquid Phase ◽  
Power Consumption ◽  
Gas Phase ◽  
Residence Time ◽  
Gas Bubbles ◽  
Liquid System ◽  
Turbulent Regime ◽  
Impeller Blade ◽  
Agitated Vessel ◽  
Turbine Impeller

AbstractResults of the experimental research on gas hold-up, power consumption for liquid phase and gas—liquid systems, and on residence time of the gas bubbles are presented in the paper for an agitated vessel with a turbine impeller. Distilled water or aqueous solutions of NaCl were used as the liquid phase. Air was dispersed into liquid as the gas phase. The studies were carried out in an agitated vessel of the inner diameter D = 0.634 m. Tubular baffles of the diameter of 0.7D, consisting of 24 vertical tubes of the diameter of 0.016D, were located inside a flat-bottomed tank. Turbines with six blades and the pitch of 90°, 60°, or 45°, respectively, were used for agitation. Measurements were carried out in the range of good dispersion of gas bubbles in the liquid within the turbulent regime of the liquid flow. Effects of the gas bubbles capability to coalesce on the gas hold-up, residence time of the gas bubbles, and power consumption were analyzed. Results of the power consumption (P G-L/P o = f 1(Kg, Fr)) and gas hold-up (φ= f 2(Kg, We, Y)) were approximated mathematically, using Eqs. (5) and (6), respectively. In Eq. (6), parameter Y was introduced in order to describe the influence of the bubbles capability to coalesce on the gas hold-up. The results of the study show that power consumption does not depend on the capability of bubbles to coalesce, but the pitch of the turbine impeller affects the power characteristics in such a physical system significantly. However, the residence time of the gas phase in agitated liquid depends on the pitch of the impeller blade and on the capability of bubbles to coalesce.

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