• Nuclear Engineering and Technology
• /
• 제53권7호
• /
• pp.2221-2228
• /
• 2021

One-dimensional oxygen transport relation is indispensable to study the oxygen distribution in the LBE-cooled system with an oxygen control device. In this paper, a numerical research is carried out to study the oxygen transport characteristics in a gas-phase oxygen control device, including the static case and dynamic case. The model of static oxygen control is based on the two-phase VOF model and the results agree well with the theoretical expectation. The model of dynamic oxygen control is simplified and the gas-liquid interface is treated as a free surface boundary with a constant oxygen concentration. The influences of the inlet and interface oxygen concentration, mass flow rate, temperature, and the inlet pipe location on the mass transfer characteristics are discussed. Based on the results, an oxygen mass transport relation considering the temperature dependence and velocity dependence separately is obtained. The relation can be used in a one-dimensional system analysis code to predict the oxygen provided by the oxygen control device, which is an important part of the integral oxygen mass transfer models.

• IEIE Transactions on Smart Processing and Computing
• /
• 제5권2호
• /
• pp.107-116
• /
• 2016

Premature babies of less than 37 weeks gestation might require oxygen therapy as an integral part of treatment and respiratory support. Because of their under-developed lungs, these so-called "preemies" might contract respiratory distress syndrome (RDS). To treat RDS, neonatal oxygen therapy is administered, where controlled oxygen gas is measured as a fraction of inspired oxygen ($FiO_2$). However, exposure to high oxygen content during long treatment could cause oxygen intoxication, which might cause permanent blindness due to retinopathy of prematurity (ROP), whereas insufficient oxygen exposure could cause severe hypoxia. A doctor would use oxygen saturation ($SpO_2$) data and prescribe a dose of $FiO_2$ to maintain $SpO_2$ within a suitable range. One objective is to maintain $SpO_2$ within the acceptable range using $FiO_2$ that is as low as possible. Adjustment of $FiO_2$ would normally be done by nurses every 15 to 30 minutes, which might not be safe in many situations. An error in $FiO_2$ adjustment during a manual procedure could be as large as +/- 2.5%. This paper presents a system that can determine an $FiO_2$ value suitable to the current $SpO_2$ and that automatically adjusts $FiO_2$ with an error clearance of +/- 0.25%.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.97.1-97
• /
• 2001

One of the main problems to constitute control method on biologically oriented wastewater purification processes, e.g. activated sludge process, sequential batch reactor, rotating bio-disk contactor, etc. is that it is hard to control the target component directly. For instance, while biochemical oxygen demand, suspended solids, and chemical oxygen demand are the key components to check the process performance, one may not control them directly since they are the results of microbial activities related to numerous physiochemical factors. Therefore controllers for bioprocess should be designed to make favorable condition for microorganisms´ living, e.g. dissolved oxygen level favorable, mixed liquor suspended solids concentration suitable ...

• 한국정밀공학회지
• /
• 제22권1호
• /
• pp.193-198
• /
• 2005

Changes in visuospatial cognitive performance, blood oxygen saturation and heart rate due to the highly concentrated oxygen administration were observed in this study. Six male ($25.8 \pm$1.0) and six female (($23.8 \pm$ 1.9) adults were asked to perform 20 visuospatial tasks with the same level of difficulties by supplying two different oxygen levels (21%, 30%). Experiment consisted of Rest1 (1 min.), Control (1 min.), Task (4 min.), and Rest2 (4 min.) and physiological signals such as blood oxygen saturation and heart rate were measured through each stage. The result showed the accuracy of task performance increased significantly at 30% oxygen concentration compared with 21%, which means oxygen supply has positive effects on visuospatial cognitive performance. When 30% oxygen was supplied, blood oxygen saturation during control and task phases was increased and heart rate was decreased compared with 21%. It means that 30% oxygen can stimulate brain activities by directly increasing the actual level of blood oxygen concentration during cognitive performance, and enough oxygen supply during cognitive performance make heart rate decrease.

• Food Science and Biotechnology
• /
• 제18권1호
• /
• pp.73-78
• /
• 2009

Processed meatball products were packaged in a passive package without oxygen scavenger as 1 control and 3 active packages of which have PP-based oxygen scavenger master batch materials (OSMB) of 40, 80, and 100%(w/w) in the middle layer and stored at 23 and $30^{\circ}C$ up to 9 months. Quality changes of packaged products were evaluated by measuring the oxygen concentration of the headspace in containers, thiobarbituric acid (TBA), color, and flavor. The oxygen concentration of the package having 100% OSMB was lower than those of 40 and 80%. The color changes and TBA values of the meat ball in the package containing 100% OSMB were the least among the treatments. Using principal component analysis (PCA), the control showed more flavor change than the packages containing oxygen scavenger. As a result, all active packages could extend the shelf life of the meatball products compared with that of the passive package.

• Corrosion Science and Technology
• /
• 제5권3호
• /
• pp.94-98
• /
• 2006

The next generation nuclear power reactor will use Pb-Bi as the cooling material. The steel structure materials such as HT-9 used in the reactor suffer from corrosion when they are exposed to high temperature Pb-Bi. Therefore corrosion should be prevented to use Pb-Bi as the coolant material without any safety problem. One method is to control the oxygen content in Pb-Bi. An appropriate amount of oxygen in Pb-Bi can produce a thin oxide layer on steel, and this layer protects the steel from corrosion attack. Since the required oxygen content in Pb-Bi is in the range of $10^{-5}$ to $10^{-7}$ wt%, this small oxygen content can be controlled by flowing a mixture of hydrogen gas and water vapor. The stagnant corrosion test of HT-9 samples was performed by controlling the oxygen content up to 2,000 hours. The corrosion behavior of HT-9 was analyzed at the temperatures of $500^{\circ}C$ and $650^{\circ}C$ with a reduced condition and a oxygen content of $10^{-6}$ wt%.

• 대한의용생체공학회:의공학회지
• /
• 제42권4호
• /
• pp.193-200
• /
• 2021

Flowmeter and oxygen sensors are listed in COVID-19 essential medical devices. This article reports a Teensy microcontroller-based Oxygen mass flow controller (MFC), core part of the oxygen respirator or extracorporeal membrane oxygenation (ECMO). The developed MFC consisting of the microcontroller, MEMS flow sensor, and solenoid valve was able to accurately control 0 to 100 sccm of oxygen flow rate. The pressure of vacuum chamber increased proportionally to the flow rate (0.998 of Pearson correlation coefficient). The experimental results proved that the developed MFC exhibits comparable performance to a commercial MFC in accuracy, settling time, linearity with pressure, and repeatability of oxygen mass flow control. It is expected that this simple and cheap MFC is utilized for oxygen therapy against the severe acute respiratory syndrome coronavirus 2.

• 환경위생공학
• /
• 제18권4호
• /
• pp.64-69
• /
• 2003

Recently, Indoor air quality(IAQ) in workplace, residential environments and office has been concern of people, scientists and related the public. The oxygen in air was very important and essential element in every aspect of life. This study was performed on a questionnaire survey of 400 people about their awareness of indoor air quality, oxygen generators and measured of oxygen concentration in indoor environment. The results obtained were as follows; As respondents are having their 90% of daytime indoors a day, and 80% of them can feel indoor air pollutions degrees directly by particle matters. The control of most important problems of IAQ was the poor ventilation. We know that 22% of the respondents was recognized the oxgen generator. And for the installation of indoor pollution control equipment, 20% of all respondents installed oxygen generators because almost respondents was not satified the trust of ability purified indoor air pollutants. In the experimental results, it was found that the oxygen concentration of sampling sites were in the range of 20~23.5%. Therefore, it was recommended that the government related IAQ was suggested the guideline and control of oxygen generators. Finally, it appeared that the oxygen generators using indoor environment can be applied to new technology for cleaning of indoor air.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
• /
• pp.1006-1011
• /
• 1991

In this paper, a neural network estimator which estimates the output of the wide range oxygen sensor is proposed, The neural network estimator is constructed to give the output of the wide range oxygen sensor from rpm, fuel injection time, throttle position, and output voltage of the exhaust gas oxygen sensor. And, using this estimator, PI controller for air-fuel ratio control is designed. Experiment results show that the proposed method gives good results for SONATA engine under light load and constant rpms.

• KSBB Journal
• /
• 제18권2호
• /
• pp.155-160
• /
• 2003

Streptoverticillium morbaraene로부터 미생물 유래 transglutaminase 생산을 위하여 최적의 용존산소 농도를 구명하였다. 용존산소는 용존산소 농도 자동 조절 시스템에 의해 조절되었다. 발효 중 용존산소 농도 조절을 위하여 통기속도는 0.3-3.9 L/min, 교반속도는 260-360 rpm으로 각각 범위를 설정하였다. 용존산소 농도를 조절한 다양한 회분식 배양에서 용존산소가 20%일 때 최대 미생물유래 transgiutaminase 생산이 가능하였다. 최분배양에서 용존산소 농도를 20%로 조절한 경우 미생물유래 transglutaminase 생산은 2.12 U/mL이었고, 용존산소를 조절하지 않은 회분식 배양의 미생물유래 transglutaminase 생산보다 1.1배 향상되었다. 역시 가장 높은 미생물유래 transglutaminase 생산은 용존산소를 20%로 조절한 유가식 배양에서 가능하였으며, 용존산소를 조절하지 않은 회분식 배양의 미생물유래 transglutaminase 생산에 비교해서 1.3배 증가하였다. 최대 건조균체량과 미생물유래 transglutaminase 생산은 각각 13.2 g/L와 2.6 U/mL이었다. 용존산소를 20%로 용존산소 농도 자동 조절 시스템에 의해 조절한 유가식 배양은 미생물유래 transgiutaminase 생산에 적절하였으며 다른 미생물 배양에도 적용할 수 있을 것으로 판단된다.