• Title/Summary/Keyword: Airflow rate

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An aerodynamic and acoustic characteristics of Clear Speech in patients with Parkinson's disease (파킨슨 환자의 클리어 스피치 전후 음향학적 공기역학적 특성)

  • Shin, Hee Baek;Ko, Do-Heung
    • Phonetics and Speech Sciences
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    • v.9 no.3
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    • pp.67-74
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    • 2017
  • An increase in speech intelligibility has been found in Clear Speech compared to conversational speech. Clear Speech is defined by decreased articulation rates and increased frequency and length of pauses. The objective of the present study was to investigate improvement in immediate speech intelligibility in 10 patients with Parkinson's disease (age range: 46 to 75 years) using Clear Speech. This experiment has been performed using the Phonatory Aerodynamic System 6600 after the participants read the first sentence of a Sanchaek passage and the "List for Adults 1" in the Sentence Recognition Test (SRT) using casual speech and Clear Speech. Acoustic and aerodynamic parameters that affect speech intelligibility were measured, including mean F0, F0 range, intensity, speaking rate, mean airflow rate, and respiratory rate. In the Sanchaek passage, use of Clear Speech resulted in significant differences in mean F0, F0 range, speaking rate, and respiratory rate, compared with the use of casual speech. In the SRT list, significant differences were seen in mean F0, F0 range, and speaking rate. Based on these findings, it is claimed that speech intelligibility can be affected by adjusting breathing and tone in Clear Speech. Future studies should identify the benefits of Clear Speech through auditory-perceptual studies and evaluate programs that use Clear Speech to increase intelligibility.

Factors Related to Exertional Oxygen Desaturation in Patients with COPD (만성 폐쇄성 폐질환(COPD) 환자에서 운동 시 발생하는 산소 불포화 반응과 관련된 인자)

  • Shim, Sang-Woo;Jo, Jun-Yeon;Kwon, Yong-Sik;Chae, Jin-Nyeong;Park, Jie-Hae;Lee, Mi-Young;Rho, Byung-Hak;Choi, Won-Il
    • Tuberculosis and Respiratory Diseases
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    • v.70 no.6
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    • pp.498-503
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    • 2011
  • Background: The causes of exertional desaturation in patients with COPD can be multifactorial. We aimed to investigate factors predict exertional desaturation in patients with moderate to severe COPD. Methods: We tested 51 consecutive patients with stable COPD (FEV1/FVC, $40{\pm}13%$ predicted). Patients performed a six minute walk test (6MWT). Pulse oxymetric saturation (SpO2) and pulse rate were recorded. Results: Oxygen desaturation was found in 15 subjects after 6MWT, while 36 subjects were not desaturated. Lung diffusing capacity was significantly lower in desaturation (DS) group ($62{\pm}18%$ predicted) compared with not desaturated (ND) group ($84{\pm}20$, p<0.01). However there was no statistical difference of FEV1/FVC ratio or residual volume between two groups. The pulse rate change was significantly higher in the desaturated compared with the not desaturated group. Six minute walking distance, subjective dyspnea scale, airflow obstruction, and residual volume did not predict exertional oxygen desaturation. Independent factors assessed by multiple logistic regression revealed that a pulse rate increment (odd ratio [OR], 1.19; 95% confidence interval [CI], 1.01~1.40; p=0.02), a decrease in baseline PaO2 (OR, 1.105; 95% CI, 1.003~1.218; p=0.04) and a decrease in lung diffusing capacity (OR, 1.10; 95% CI, 1.01~1.19; p=0.01) were significantly associated with oxygen desaturation. Receiver operator characteristic (ROC) analysis showed that an absolute increment in pulse rate of 16/min gave optimal discrimination between desaturated and not desaturated patients after 6MWT. Conclusion: Pulse rate increment and diffusion capacity can predict exertional oxygen desaturation in stable COPD patients with moderate to severe airflow obstruction.

Influence of the Cyclic Parameters on the Nitric Oxide Formation in the diesel Engine

  • Rosli Abu Bakar
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.1
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    • pp.27-35
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    • 1998
  • This study describes the influence of combustion parameters on the nitric oxide emission, such as injection timing, air flow rate, injected amount of fuel, and compression ratio of engine. In order to determine the influence factors on the nitric oxide emission, the experiment were investigated with various parameters of engine cycle. According to the results of this study, the retardation of injection timing and the increases of airflow rate, and the decreases of fuel injection amount reduce the nitric oxide concentration in the exhaust emissions. Also, the increases of compression ration of engine increase in the concentration of nitric oxide formation in the combustion chamber. The results of this study give a guideline to decrease the nitric oxide formation by using the simulation program.

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A Study on the Improvement of Cross Ventilation Efficiency in a Tower Type Apartment in Summer Season (탑상형 아파트의 여름철 통풍성능 개선에 대한 연구)

  • Cho, Keun-Je;Chang, Hyun-Jae
    • 한국태양에너지학회:학술대회논문집
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    • 2012.03a
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    • pp.299-304
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    • 2012
  • In terms of plane structure, tower-type apartments have several disadvantages compared to flat-type apartments in the aspect of ventilation rate. Such disadvantages may not produce good indoor cooling effects with natural ventilation inside the heated apartments in hot summer days, so they may cause high energy consumption by an increase in cooling load. The purpose of this study is to investigate ways for improving the indoor thermal environment of tower-type apartments in summer by conducting quantitative evaluations of the airflow distribution in households.

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The Aerodynamic Analysis between Normal Voice and Esophageal Voice (정상인과 식도발성 음성에서의 공기역학적 비교 연구)

  • 박국진;최홍식;정형진;유신영;박준호;김한수
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.9 no.1
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    • pp.5-10
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    • 1998
  • Voice rehabilitation is very important concerning in laryngectomees. Esophageal speech is a common and widely used method of voice restoration. But, until now there is no reliable data which shows the aerodynamic characteristics of esophageal speech. In order to evaluate the vocal quality of normal laryngeal and esophageal speech, several aerodynamic parameters were measured in 13 adults with normal laryngeal voice and 2 excellent esophageal speakers using Aerophone II voice function analyzer. The examined parameters were maximal flow rate, mean airflow rate, subglottic pressure, vocal efficiency, glottic resistance, maximal phonation time and mean sound pressure level. In vocal efficiency, there is no difference between two groups, but in other parameters, marked differences were showed in esophageal speakers, especially mean resistance. Results indicates that esophageal speakers make the efficient voices with poor aerodynamic condition, comparing with normal laryngeal speakers.

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A Study on the Optimal Orifice Location for Air flow Measurement in an Air Duct Leakage Tester (덕트누기시험기용 풍량측정 오리피스의 최적위치 선정에 관한 연구)

  • Lee Seung-Chul
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.18 no.2
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    • pp.186-191
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    • 2006
  • In this study, five experiments were carried out, with an orifice located downstream of a fan in case I where upstream duct length is 6 D, and that in the downstream is 4 D and different downstream distance to the fan in the rest, so as to determine the optimal location of the orifice and reduce the duct length of airflow measurement device. The resulting flow rate-pressure drop correlations were found to satisfy the limitation of SMACNA standard, which specified an error of $\pm7.5\%$ based on the real flow rate. Also, the best one of five. cases was achieved with the orifice located midway of the orifice duct four times its diameter long.

Optimal Location of Orifice in Duct Leakage Tester for Air Flow Measurement (덕트누기시험기용 풍량측정 오리피스의 최적위치 선정에 관한 연구)

  • Lee, Seung-Chul;Park, Man-Heung;Kim, Kwang-Chu
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.2151-2156
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    • 2004
  • In this study, five experiments were carried out, with an orifice located downstream of a fan in case I and upstream distance to the fan in the rest cases(case $II{\sim}$), so as to determine the optimal location of the orifice and reduce the size of airflow measurement device. The resulting flow rate-pressure drop correlations were found to satisfy the limitation of SMACNA standard, which specified an error of ${\pm}7.5%$ based on the real flow rate. The best outcome was achieved with the orifice located midway of the orifice duct 4 times its diameter long.

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An Analysis of Indoor Thermal Environment by Macro Model (매크로 모델에 의한 실내온열환경 검토)

  • Jung, Jae-Hoon
    • Proceedings of the SAREK Conference
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    • 2008.11a
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    • pp.584-589
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    • 2008
  • It is known that slab thermal storage which uses concrete slab as thermal material is effective in the load leveling and using the nighttime electric power. The temperature distribution is not constant in plenum in thermal storage time by beams, ducts such as several factor. It is considered that this fact will effect on efficiency of thermal storage and indoor thermal environment. The purpose of this paper is to examine the thermal environment inside plenum. A macro model was made for the analysis of indoor thermal environment as the first step. The flow rate distribution and temperature distribution of object room model was examined by use of basic equations such as airflow by the pressure difference between unit cells, heat flow by air and heat transfer.

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Analyzing for Refrigerant Induced Noise for Split type Air Conditioner Indoor Unit (분리형 에어컨의 실내기 냉매 소음 저감 분석)

  • Han, Hyung-Suk;Aoyama, Shingeo;Mo, Jin-Yong;Lee, Jae-Kwon;Song, Yong-Jae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.421-426
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    • 2005
  • For the air-conditioner, refrigerant induced noise and vibration should be the problem when it reduced airflow rate in order to reduce the noise at low mode. With the test, it could be verified that one of the main reason for refrigerant induced noise were the velocity and flowing induced force of the refrigerant at the inlet of evaporator. So in order to reduce this velocity with same mass flow rate of refrigerant, quality at the evaporator inlet should be minimized. And in order to reduce flowing induced force of the refrigerant, flowing direction change should be eliminated. So in this paper, it would like to review the characteristics of refrigerating cycle at first and find how the quality and flowing induced force can be minimized.

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Numerical evaluation of risk rates for contamination sources in a minienvironment (클린룸 국소환경에서 오염원의 위험율에 대한 수치해석적 평가)

  • Noh, Kwang-Chul
    • Particle and aerosol research
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    • v.14 no.4
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    • pp.181-189
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    • 2018
  • In this study, the risk rates of different contamination sources of the contaminant in a minienvironment were analyzed through Computational Fluid Dynamics (CFD) simulation. The airflow pattern characteristics can only predict the qualitative variation of contaminant concentration, but cannot evaluate the quantitative variations in the risk rate of sources. From the results, the ambient contamination sources mainly affect wafers in the Front Opening Unified Pod (FOUP), whereas the internal contamination sources mainly affect wafers laid on the robot arm in the minienvironment. And the purging plenum system is very useful in protecting the wafers in the FOUP from contaminants transferred from the Fan Filter Unit (FFU). However, this system is unable to protect the wafers on the robot arm from internal contaminants and the wafers in the FOUP from sources of the interface between the FOUP and the minienvironment.