• Tunnel and Underground Space
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• v.25 no.2
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• pp.186-198
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• 2015

This paper aims for the ultimate goal to optimize the work place environment through assuring the optimal required ventilation rate based on the analysis of the airflow. The working environment is deteriorated due to a rise in temperature of a coal mine caused by increase of its depth and carriage tunnels. To improve the environment, the ventilation evaluation on J coal mine is carried out and the effect of a length of the tunnel on the temperature to enhance the ventilation efficiency in the subsurface is numerically analyzed. The analysis shows that J coal mine needs $17,831m^3/min$ for in-flow ventilation rate but the total input air flowrate is $16,474m^3/min$, $1,357m^3/min$ of in-flow ventilation rate shortage. The temperatures were predicted on the two developed models of J mine, and VnetPC that is a numerical program for the flowrate prediction. The result of the simulation notices the temperature in the case of developing all 4 areas of -425ML as a first model is predicted 29.30 at the main gangway 9X of C section and in the case of developing 3 areas of -425ML excepting A area as a second model, it is predicted 27.45 Celsius degrees.

• Clinical and Experimental Pediatrics
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• v.49 no.11
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• pp.1194-1201
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• 2006

Purpose : The comatose mentality can be catastrophic, especially if the condition is severe or the duration is prolonged. Therefore, delayed diagnosis can result in a poor outcome or death. The best radiologic modality to differentiate from cerebral lesions in patients suffering from cerebral diseases is magnetic resonance imaging (MRI) rather than computed tomography (CT). Special apparatuses with metal materials such as ventilators, and cardiac pacemakers belonging to patients cannot be located in the magnetic field. We aimed to exhibit the possibility of examining MRI, maintaining ventilation at a relative long distance by means of modified $Ambu^{(R)}$. Methods : Self-inflating bags as a sort of a manual ventilator, connected with relatively long extension tubes instead of mechanical ventilators, were adopted to obtain MRI. PVC (polyvinyl chloride) extension tubes had different lengths and diameters. Lengths were 1, 2, and 3 cm and diameters were 15, and 25 mm. The work of breathing and expiratory changes of expiratory tidal volume (TVe), minute volume of expiration (MVe), peak inspiratory pressure (PIP) were measured by use of the mechanical ventilator, $Servoi^{(R)}$, as the alteration of TVi (inspiratory tidal volume), extension tube lengths and diameters with other values fixed. Results : Measured TVe and MVe by ventilator were the same values with control at every TVi, regardless of extension tube lengths and diameters, but PIP were increased with the rise of TVi, tube lengths, with decline of tube diameters, these were statistically significant. Conclusion : MRI examination can be carried out with a self-inflating bag connected with an extension tube at a long distance in patients who need artificial ventilation.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.140.2-140.2
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• 2014

인공위성은 우주공간의 고진공 상태와 태양 복사열에 의한 고온 및 극저온이 반복되는 가혹한 환경으로 인해 주요 부품의 기능장애가 초래되므로 발사전 지상에서 열진공 시험장비를 이용한 열진공시험을 수행한다. 위성체의 열진공 시험에 사용되는 열교환기인 베이스플레이트(Baseplate)는 우주 열환경을 모사하기 위하여 직접 방열판 표면에 고온 및 저온의 유체를 공급하여 시험 요구에 따른 필요한 열을 공급하게 된다. 일반적으로 우수한 성능의 위성체 부품의 검증을 위해서 지상의 열환경 시험은 접촉식 히터 및 열교환기를 사용하게 되는데, 이때 적절한 히터 및 블로워 파워를 선정하고 챔버 슈라우드와 열교환에 있어 간섭이 없도록 장비를 운용해야 한다. 본 연구에서는 상용프로그램을 이용하여 열진공 시험용 베이스플레이트에 대하여 전산해석을 수행하였으며, 이를 통해 베이스플레이트 내의 작동 유체의 입구 압력에 의한 열진공 시험용 열교환기의 성능 특성을 관찰하였다.

• Clinical and Experimental Pediatrics
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• v.45 no.10
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• pp.1204-1212
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• 2002

Purpose : Early surfactant therapy with either gentle ventilation, high-frequency ventilation or aggressive weaning of mechanical ventilation are principles for the treatment of respiratory distress syndrome(RDS). We studied to determine the accessibility of noninvasive nasal continuous positive airway pressure(CPAP) rather than mechanical ventilation by invasive intubation after early surfactant therapy. Methods : The study group consisted of 14 infants who were born and diagnosed with moderate respiratory distress syndrome and received early surfactant therapy with nasal CPAP of PEEP 5-6 cm $H_2O$ within two hours after birth in the Fatima neonatal intensive care unit for two years from January 1999 to August 2001. The control group consisted of 15 infants who were diagnosed with the disease and could be weaned from mechanical ventilator within five days after birth during the same period. Results : The characteristics, the severity of clinical symptoms and laboratory findings in the two groups at birth showed no significant difference. Neither did the interim analysis of laboratory data in two groups. Of 14 infants in the study group who received nasal CPAP after early surfactant therapy, only two infants showed weaning failure with this therapy. In the response cases, duration of CPAP was five days and mean airway pressure was $5.4{\pm}0.5cm$ $H_2O$. Two had the complication of CPAP with abdominal distension. Final complications and outcomes in the two groups showed no signifcant difference(P>0.05). Conclusion : The clinical courses in the two groups showed no significant difference. Therefore, we suggest that early surfactant therapy with noninvasive nasal CPAP is a simple and safe method rather than aggressive weaning after invasive mechanical ventilation in moderate respiratory distress syndrome.

• Clinical and Experimental Pediatrics
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• v.46 no.10
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• pp.966-971
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• 2003

Purpose : It is now well established that infection and inflammation play an important role in the pathogenesis of ischemic brain damage. The loss of neutrophils from systemic circulation is an associated finding in injury mediated by granulocyte. Periventricular leukomalacia(PVL) caused by ischemia is the principal form of brain injury in premature infants. This study was conducted to evaluate whether the low neutrophil count is associated with periventricular leukomalacia(PVL) in premature infants. Methods : Retrospective review of medical records was undertaken. Subjects were premature infants with a birth weight of less than 1,500 gm, admitted to the Neonatal Intensive Care Unit of Kyungpook University Hospital. A complete blood count of peripheral blood was done within the 1st hour of life. Neutropenia was defined as absolute neutrophil count < $1,500/mm^3$, PVL as increased periventricular echodensities followed by cyst formation on ultrasonography or corresponding signs on brain MRI. Results : Thirteen infants out of a total population of 37 revealed neutropenia. Respiratory distress syndrome and requirement for respiratory support were not different between infants with neutropenia( neutropenia group) and infants without neutropenia(control group). Intraventricular hemorrhage (IVH) and grade 3 and 4 IVH were more frequent in neutropenia group(P<0.05). There was no statistically significant increase of PVL in neutropenia group. The neutrophil count was $18,760.0{\pm}10,266.1/mm^3$, $7,272.0{\pm}7,435.0/mm^3$ infants with PVL and $11,131.7{\pm}3,386.5/mm^3$, $2,407.5{\pm}1,933.1/mm^3$ in infants without PVL, respectively. The frequency of mechanical ventilation and artificial surfactant therapy was higher in infants with PVL compared with infants without PVL, but statistical analysis was not performed due to small number of subjects. Conclusion : A low number of neutrophils in the systemic circulation was not associated with an increased risk of PVL in premature infants.

• Tunnel and Underground Space
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• v.13 no.6
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• pp.434-443
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• 2003

In this study, it was purposed to develop the new method for the prediction of pollutant concentration in road tunnels. The new method was the use of artificial neural network with the back-propagation algorithm which can model the non-linear system of tunnel environment. This network system was separated into two parts as the visibility and the CO concentration. For this study, data was collected from two highway road tunnels on Yeongdong Expressway. The tunnels have two lanes with one-way direction and adopt the longitudinal ventilation system. The actually measured data from the tunnels was used to develop the neural network system for the prediction of pollutant concentration. The output results from the newly developed neural network system were analysed and compared with the calculated values by PIARC method. Results showed that the prediction accuracy by the neural network system was approximately five times better than the one by PIARC method. In addition, the system predicted much more accurately at the situation where the drivers have to be stayed for a while in tunnels caused by the low velocity of vehicles.

• Clinical and Experimental Pediatrics
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• v.46 no.2
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• pp.192-194
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• 2003

A neonate born at 38 gestational weeks was admitted due to generalized tonic-clonic seizure and cyanosis. The neonate was born six days previously at home through normal delivery and the umbilical cord was cut using scissors sterilized in boiling water. The neonate weighed 3,180 g at admission. Physical examination revealed cyanosis, opisthotonus, trismus and reactive muscle spasms. Laboratory exam, brain sonogram and EEG showed no significant abnormal findings. Based on her history and physical examination, the neonate was diagnosed with tetanus and put in an incubator isolated in a quiet, dark room. Treatment with tetanus human immunoglobulin along with antibiotics (penicillin G) were started immediately, and mechanical ventilation, administration of neuromuscular blocking agent and muscle relaxant were also started off. The frequency of seizure episode decreased gradually, and on the 32nd hospital day, mechanical ventilatory support was stopped along with extubation two days later. Thereafter, the neonate was in continuous generalized hypertonic state and showed feeding difficulty, but there was gradual improvement. She was dismissed on the 49th hospital day and is currently under OPD follow-up, doing well with no special problems. Respiratory management is critical to neonatal tetanus. We report here a case of tetanus treated with inhibition of self-respiration, neuromuscular blocker and application of ventilator, and present this method as a useful direction for future treatment of neonatal tetanus.

• Clinical and Experimental Pediatrics
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• v.52 no.4
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• pp.429-434
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• 2009

Purpose : Severe aspiration of the amniotic fluid is known to cause fatal respiratory distress in neonates. We conducted this study to investigate the clinical findings of severe amniotic fluid aspiration pneumonia (AFAP) in neonates and the effect of pulmonary surfactant replacement therapy (SRT). Methods : Retrospective analysis of medical records was conducted on 28 patients who received ventilator care due to severe AFAP in a neonatal intensive care unit over a 7-year period (2000-2006). Patients whose amniotic fluid was contaminated with meconium were excluded. Results : A large number of cases were term infants (82.1%) and infants born by caesarean section (85.7%), and the 1- and 5-min Apgar scores of these patients were $6.5{\pm}1.2$ and $7.5{\pm}1.3$, respectively. Soon after birth, the amount of amniotic fluid sucked out from airway below the vocal cord was $16.0{\pm}10.1$ mL. All patients received SRT with a modified bovine-derived surfactant (120 mg/kg/dose), and one dose was administered in most cases (75%). Compared with pre-SRT, the oxygenation index ($8.0{\pm}9.6$ vs. $18.9{\pm}7.3$) according to ventilator care was a significant improvement at 12 h after SRT (P<0.001). Furthermore, most cases showed radiological improvement for aeration at 12 h post-treatment. Many cases (46.4%) had cardiorespiratory complications, but their final outcomes were excellent (survival rate, 96.4%). Conclusion : AFAP may be an important cause of serious respiratory distress in near-term and term infants, and SRT seems to be an effective adjuvant therapy in mechanically ventilated neonates with severe AFAP.

• Child Health Nursing Research
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• v.17 no.2
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• pp.145-152
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• 2011

Purpose: To evaluate the efficacy of Optimal humidification during Nasal Continuous Positive Airway Pressure (nCPAP) for Extremely Low Birth Weight Infant (ELBWI). Methods: The study design was a pre-test-post-test nonequivalent nonsynchronized quasi-experimental design. The participants were 218 ELBWI on nCPAP (experimental group: 102 and control group: 116). Data collection was conducted from January 2005 to April 2010. In order to measure and analyze the nCPAP duration, reintubation and nasal condition, Chi-square test and t-test were used. Results: Hypothesis 1, that the duration with nCPAP in the experimental group is longer than that of the control group and hypothesis 2-3, that the rate of reintubation and nasal problems in the experimental group are lower than the control group, were all supported as there were statistically significant differences between two groups. Conclusion: The findings suggest that the Optimal humidification in this study is an efficient intervention because it helps increase the last time of nCPAP with ELBWI and minimize complications. It is expected that Optimal humidification is beneficial and helpful in preventing and caring for respiratory problems in these infants.

• Fire Science and Engineering
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• v.31 no.2
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• pp.113-118
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• 2017

The purpose of this study was to compare the ventilatory volume and airway pressure using Oxylator EM-100, MicroVenT CSI-3000, OXY-LIFE II. The data were obtained from February 13 in 2017 andanalyzed using the SPSS WIN 18.0 program. The results of theventilatory volume showed the Oxylator EM-100 551.44 ml (${\pm}18.70$), MicroVenT CSI-3000 527.26 ml (${\pm}17.98$), and OXY-LIFE II 369.46 ml (${\pm}12.30$). The airway pressure showed the Oxylator EM-100 $11.89cmH_2O$ (${\pm}.41$), MicroVenT CSI-3000 $11.66cmH_2O$ (${\pm}.34$), and OXY-LIFE II $8.02cmH_2O$ (${\pm}.25$). This study will provide the basic data for an appropriate ventilation method by an oxygen supply device including Oxylator EM-100, MicroVenT CSI-3000, and OXY-LIFE II.