• 한국환경보건학회지
• /
• 제19권4호
• /
• pp.44-50
• /
• 1993

This paper has concentrated on estimating the improvement of sludge dewaterability for the application of ozone in sewage treatment plant sludge. The experiment for the study was conducted by batch reactor, contacting ozone (5.0 g O$_3$/hr/l) to waste sludge and measured the Specific Resistance to Filtrate (SRF) varying pH, pressure and reaction time of ozone. And then checked the dissolved solids concentration of flitrate. The results of experiment were as follows: 1. When the total solids concentration of excess sludge was 9, 000 mg/l, the optimum injection rate of ozone was 5.0 g O$_3$/hr/l, and then pressure was 50 cm Hg for the measuring SRF. 2. In the range of pH 3~5, the effect of ozone injection was excellent, but it was unsatisfactory in the range of pH 9~11. Therefore, the ozone injection by acidifying pH level was effective in improving the dewaterability of sludge. 3. It was estimated that the dissolved solids concentration of flitrate was increased in proportion to the injection rate of ozone.

• 디지털콘텐츠학회 논문지
• /
• 제18권4호
• /
• pp.699-706
• /
• 2017

근육 주사 후 진동과 압력을 이용한 마사지기구와 손마사지를 환자에게 제공 하여 주사 후 통증과 통증지속시간에 미치는 효과를 비교 검증하는 것이다. 연구의 방법은 비동등성대조군 유사 실험 설계 이다. 실험 결과 실험군이 대조군보다 통증점수가 더 낮았고(t= 7.40, p =.001), 통증 지속시간도 더 짧았다(t= 5.25, p=.001). 실험을 통하여 근육 주사 후 손마사지 방법보다 진동과 압력을 이용한 마사지기를 적용하는 것이 환자의 통증 및 통증 지속시간을 감소시킬 수 있음을 보여주었다. 따라서 근육주사 후 진동과 압력을 이용한 마사지기를 적용하는 것이 환자의 안위 증진은 물론 간호사의 업무량 감소에도 긍정적인 영향을 줄 것으로 기대된다.

• 한국자동차공학회논문집
• /
• 제21권4호
• /
• pp.89-95
• /
• 2013

In this work, the evaluation of swirl nozzle injector performance was conducted by investigating effective area ($A_{eff}$), injection mass ($m_{inj}$), injection rate ($Q_{inj}$), and injection delay ($t_{delay}$) under various test conditions. To achieve these, fuel injection analysis system which was composed of fuel supply system, injection system, and control system was installed. At the same time, the swirl nozzle that had 12 orifice hole with $120^{\circ}$ injection angle was used in this work. It was revealed that the difference of injection mass ($m_{inj}$) between base and swirl nozzle injector increased as the injection pressure ($P_{inj}$) and energizing duration ($t_{eng}$) decreased under the same test conditions. The maximum injection rate ($Q_{inj}$) of swirl nozzle injector was higher than base nozzle injector about 2~5%. The injection performance of swirl nozzle was better than base nozzle at low injection pressure ($P_{inj}$) and short energizing duration ($t_{eng}$) conditions.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 1996년도 연약지반처리위원회 봄 학술세미나
• /
• pp.1-20
• /
• 1996

• 대한치과마취과학회지
• /
• 제6권2호
• /
• pp.98-102
• /
• 2006

The purpose of this study was to evaluate the difference on pain intensity and discomfort between pressure-controlled injection system and conventional syringe injection technique from the patients undergoing oral and maxillofacial surgery. In a prospective, randomized, case-controlled study, 60 patients were divided into two groups (n=30 in each). In experimental group, pressure-controlled injection system was applied. In control group, conventional syringe injection system was applied. Pain rating score (PRS) and visual analogue scale (VAS) were assessed. The average of VAS in experimental group ($16.67{\pm}15.07$) was smaller than that of control group ($25.63{\pm}22.21$), though there were no significant differences (P=0.072). In PRS, fifteen patients (50.0%) of experimental group answered that they experienced mild pain. However sixteen patients (53.3%) of control group answered that they experienced intermediate pain. From the results, pressure-controlled injection system may be an effective method to reduce pain during the dental local anesthetic procedure.

• Journal of Advanced Marine Engineering and Technology
• /
• 제40권4호
• /
• pp.295-300
• /
• 2016

P사의 실린더 당 210 kW 급 중속디젤엔진의 연료분사펌프를 대상으로 연료 송출 압력파에 대해서 Ansys Fluent R15.0을 사용하여 수치 해석하였다. 연료 송출 압력파의 실험 결과와 수치 해석 결과가 유사하게 나타났으며, 전산유체역학을 이용한 연료분사펌프의 연료 송출 압력파에 대한 수치 해석의 신뢰성을 확인하였다.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
• /
• pp.569-572
• /
• 2006

In present study, the influence of changing combustor pressure on flame stabilization and nitrogen oxide (NOX) emission in the swirl flame with secondary fuel injection was investigated. The combustor pressure was controlled by suction at combustor exit. Pressure index ($P^*=Pabs/Patm$), where Pabs and Patm indicated the absolute pressure and atmosphere pressure, was controlled in the range of 0.7~1.15 for each equivalence ratio conditions. It could be observed that flame stable region became narrower with decreasing equivalence ratio and pressure index. In this combustion system, stable flames were formed until $P^*=\;0.7$. Emission index decreased with decreasing pressure index for overall equivalence ratio conditions and NOx reduction rates were almost identical for $P^*<1$ regardless of equivalence ratio though EINOx values showed different level with change of equivalence ratio for $P^*{\geq}1$. It is also observed that EINOx decreased with increasing secondary fuel injection ratio. Emission index of nitric oxide was controllable by adjusting the changing combustor pressure and injecting secondary fuel and this NOx reduction technology is applicable to industrial furnaces and air conditioning system.

• 한국환경과학회지
• /
• 제20권1호
• /
• pp.25-34
• /
• 2011

The new empirical static model was constructed on the basis of dimension analysis to predict the pressure drop according to the operating conditions. The empirical static model consists of the initial pressure drop term (${\Delta}P_{initial}$) and the dust mass number term($N_{dust}=\frac{{\omega}_0{\nu}_f}{P_{pulse}t}$), and two parameters (dust deposit resistance and exponent of dust mass number) have been estimated from experimental data. The optimum injection distance was identified in the 64 experimental data at the fixed filtration velocity and pulse pressure. The dust deposit resistance ($K_d$), one of the empirical static model parameters got the minimum value at d=0.11m, at which the total pressure drop was minimized. The exponent of dust mass number was interpreted as the elasticity of pressure drop to the dust mass number. The elasticity of the unimodal behavior had also a maximum value at d=0.11m, at which the pressure drop increased most rapidly with the dust mass number. Additionally, the correlation coefficient for the new empirical static model was 0.914.

• 대한수의학회지
• /
• 제42권1호
• /
• pp.123-130
• /
• 2002

To investigate the cardiopulmonary and anesthetic effects of propofol in dogs, experimental dogs were randomly divided into 4 groups (propofol infusion anesthesia, P/INF, propofol intermittent anesthesia, P/INTER, propofol induction anesthesia, P/ISO, thiopental Na induction anesthesia, T/ISO) and monitored analgesic and anesthetic effects, recovery time, body temperature, heart rate, mean arterial pressure, respiratory rate, systolic and diastolic pressure. In all groups, apnea was not observed. In the P/INF group, the respiratory rate(RR) was slightly decreased, but in the P/INTER group, RR was increased and shallowing. In the groups of P/ISO and T/ISO, the respiratory rate was decreased. Heart rate(HR) was increased after induction anesthesia in all groups, but gradually decreased. Mean arterial pressure(MAP) was decreased after injection anesthesia in the groups of P/INF and P/INTER. In the groups of P/ISO and T/ISO, however, MAP was slightly increased. Systolic and diastolic arterial pressure were gradually decreased after induction anesthesia, but not significantly. In the groups of P/INF and P/ISO, recovery time was shorter than the groups of P/INTER and T/ISO. In all groups, body temperature of animals was decreased gradually according to time but no significant changes were observed. Propofol injection doesn't make the complete loss of responses of animals, especially, in the P/INTER group. In the P/INF group, deep pain was present until the end of anesthetic period. During recovery period, any other side effects except incoordination were not monitored. The present study suggested that infusion anesthesia was superior to intermittent anesthesia as injection anesthetic agent, and propofol was better than thiopental Na as induction anesthetic agent.

• 대한간호학회지
• /
• 제39권2호
• /
• pp.270-278
• /
• 2009

Purpose: This study was performed to find out the effects of lidocaine or 8.4% sodium bicarbonate mixed with rocuronium on mean arterial pressure, heart rate and withdrawal movement. Methods: Data collection was performed from December 15, 2006 through May 31, 2007. Seventy-five patients with American Society Anesthesiologist (ASA) physical status I & II, under general anesthesia, were randomly assigned to 1 of 3 groups: R group (RG) received rocuronium 0.6 mg/kg; RL group (RLG), rocuronium 0.6 mg/kg mixed with 2 mL of 2% lidocaine; RS group (RSG), rocuronium 0.6 mg/kg with the same volume of 8.4% sodium bicarbonate. Mean arterial pressure, heart rate and withdrawal movement were observed from its injection until 5 min after endotracheal intubation. Results: The incidence of withdrawal movement with its corresponding injections was 72%, 40% and 4% in RG, RLG and RSG, respectively (p<.001). Score of withdrawal movement was the lowest in RSG of all groups (p<.001). While mean arterial pressure (p=.011) in RSG decreased significantly, and heart rate (p=.003) in RG increased more with its injection than before induction of anesthesia. Conclusion: Administration of the equivalent volume of 8.4% sodium bicarbonate with rocuronium is more effective than that of lidocaine with rocuronium compared with rocuronium only, in preventing withdrawal movement and in stabilizing mean arterial pressure and heart rate.