Articoli di riviste: "Induced airflow"

1

Freed, Arthur N., e Carol A. Hirshman. "Airflow-induced Bronchoconstriction". Anesthesiology 69, n. 6 (1 dicembre 1988): 923–32. http://dx.doi.org/10.1097/00000542-198812000-00019.

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Adámek, Karel. "Induced Airflow Around the Calendering Drums". International Journal of Mechanical Engineering and Applications 1, n. 1 (2013): 10. http://dx.doi.org/10.11648/j.ijmea.20130101.12.

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3

Nayyar, Abhishek, e Vesselin Stoilov. "Power Generation from Airflow Induced Vibrations". Wind Engineering 39, n. 2 (aprile 2015): 175–82. http://dx.doi.org/10.1260/0309-524x.39.2.175.

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4

Freed, A. N., K. T. Yiin e C. E. Stream. "Hyperosmotic-induced bronchoconstriction in the canine lung periphery". Journal of Applied Physiology 67, n. 6 (1 dicembre 1989): 2571–78. http://dx.doi.org/10.1152/jappl.1989.67.6.2571.

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Hypertonic aerosol- and dry airflow-induced bronchoconstriction were examined in the canine lung periphery by the use of a wedged bronchoscope technique. Collateral resistance was measured in anesthetized dogs before and after exposure to isotonic and hypertonic aerosols and dry airflow. Hypertonic aerosols produced significantly greater responses than isotonic aerosols, and resistance increased in an exposure-dependent manner. Atropine attenuated responses to these challenges, indicating that aerosol-induced peripheral lung constriction was, in part, muscarinic in origin. Paired hypertonic- and dry airflow-induced constriction exhibited marked differences in magnitude and time course: responses to hypertonic aerosol peaked immediately; dry air-induced responses rose slowly to a maximum 5-min postchallenge. These differences may reflect differences in stimulus strength or differences in the regulatory pathways activated by each challenge. Despite this, a significant correlation exists between aerosol- and dry air-induced responses in the canine lung periphery and suggests that changes in airway fluid osmolality have an important role in the initiation of airflow-induced bronchoconstriction.

5

Zhang, Ying, Thomas Olofsson, Gireesh Nair, Chenbo Zhao, Bin Yang e Angui Li. "Cold windows induced airflow effects on the thermal environment for a large single-zone building". E3S Web of Conferences 172 (2020): 06003. http://dx.doi.org/10.1051/e3sconf/202017206003.

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With access to modern building technologies and HVAC-systems, it is possible to obtain low energy use and good thermal comfort for complex design, such as large building volumes. However, the situation is different for large single zone buildings with large volumes. They often have insufficient thermal comfort. The problem could be partially attributed to the unwanted airflows due to the cold surfaces, especially the windows. With increased knowledge of the airflow, it is possible to identify suitable renovation strategies in such buildings. In this work, we study a church building with mechanical air change system and floor heating. CFD-simulations with dynamic airflow was conducted based on building geometries and technical data. The validation was based on data from the ventilation control and the space-heating system. The results show how the window-to-wall ratios and the positions of windows affect the thermal comfort. It contributes with knowledge of advantages and disadvantages of different envelope design in the existing environment with floor heating.

6

Wang, Huan, Maohui Luo, Guijin Wang e Xianting Li. "Airflow pattern induced by ceiling fan under different rotation speeds and blowing directions". Indoor and Built Environment 29, n. 10 (25 novembre 2019): 1425–40. http://dx.doi.org/10.1177/1420326x19890054.

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Ceiling fans have been widely used as effective cooling and air mixing method for building environment conditioning. Understanding its airflow characteristics can be helpful to utilize ceiling fan or integrate it with background air conditioning system. However, the airflow induced by ceiling fan has different flow patterns under different rotating speeds and blowing directions. To date, it is still challenging to capture those complicated airflow fields in room scale. In this study, the airflow pattern induced by a ceiling fan was measured with a new technology, quad-view colour sequence particle streak velocimetry. A series of isothermal experiments were conducted under five rotation speed levels with downward and upward blowing directions in a room-size (4 m × 2.5 m × 3 m) chamber. Based on comprehensive three-dimensional three-component vector measurement results, the average velocity, turbulence intensity and vorticity on the middle section were calculated and used to analyse airflow patterns induced by ceiling fan. The results show that the blowing direction of the fan determines the indoor airflow pattern. When blowing downward, the flow will cause high diversion between jet core under the fan blades and surrounding region. While for upward blowing, the air speed in lower part of the room is much lower but pretty uniform. The detailed measured airflow fields can serve as reference for ceiling fan design and operation.

7

Dong, Hao, Zheng Li, Xi Geng, Zhiwei Shi e Qijie Sun. "Study of the airflow induced by a sliding discharge plasma actuator". Modern Physics Letters B 33, n. 02 (20 gennaio 2019): 1950011. http://dx.doi.org/10.1142/s0217984919500118.

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Sliding discharge, as a new type of electrical discharge, is being gradually applied in plasma active flow control in recent years. In this work, the particle image velocimetry (PIV) experiments were conducted to investigate the airflow characteristics induced by the sliding discharge plasma actuator at varied voltage signals. The results show that the integral thrust produced by the negative alternating current (AC) power is stronger than normal AC power under the same voltage magnitude. The induced airflow direction changes along with the changing of two power voltage signals. Furthermore, the angle of the induced airflow is mainly linear with the loading voltage.

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Wright, Joanne L., Victor Tron, Barry Wiggs e Andrew Churg. "Cigarette Smoke Potentiates Asbestos-Induced Airflow Abnormalities". Experimental Lung Research 14, n. 4 (gennaio 1988): 537–48. http://dx.doi.org/10.3109/01902148809087826.

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9

Adámek, Karel, e Jan Kolář. "Influence of the induced airflow on calendering". EPJ Web of Conferences 25 (2012): 01002. http://dx.doi.org/10.1051/epjconf/20122501002.

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10

Wang, Ze, Jingang Qu e Pascal Morin. "Airflow-based odometry for MAVs using thermal anemometers". International Journal of Micro Air Vehicles 15 (gennaio 2023): 175682932211483. http://dx.doi.org/10.1177/17568293221148385.

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This article concerns airflow-based odometry for estimating MAV flight speed from airflow measurements provided by a set of thermal anemometers. Our approach relies on a Gated Recurrent Unit (GRU) based deep learning approach to extract deep features from noisy and turbulent measurement signals of triaxial thermal anemometers, in order to establish the underlying mapping between the airflow measurement and the flight speed. The proposed solution is validated on a multi-rotor MAV. The results show that the GRU-based model can effectively extract noise features and perform denoising, and compensate for induced velocity effects along the propellers’ rotation axis. As a consequence, robust prediction of the flight speed is performed, including during takeoff and landing that induce ground effects and strong variations of vertical airflow.

11

Osabutey, Augustina, Brady Cromer, Alexander Davids, Logan Prouty, Noor Haleem, Robert Thaler, Richard Nicolai e Xufei Yang. "Distribution of Airflow and Media Moisture Content across Two Vertical Bed Biofilters". AgriEngineering 4, n. 1 (24 febbraio 2022): 179–89. http://dx.doi.org/10.3390/agriengineering4010013.

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For its small square footage, a vertical bed biofilter was developed for odor emission mitigation for livestock facilities with limited area available for biofilter installation. However, a concern about the design is that airflow and moisture may be poorly distributed across the biofilter due to the effects of gravity. Relevant data are sporadic in the literature. To fill the knowledge gap, two vertical bed biofilters were constructed at a university swine facility and monitored for two months. The monitoring was taken at 27 grid points on each biofilter per field visit. Results revealed that both the airflow and medium moisture content were unevenly distributed. The sun-facing side of the biofilters had significantly lower medium moisture content (p < 0.01) due to solar-induced water evaporation. The side directly facing the barn exhaust had the highest airflow. Airflows varied along the height of the biofilters, but no significant difference was noted. The uniformity of airflow and moisture content, characterized by coefficient of variance (CV) and distribution uniformity (DU) respectively, were examined over the monitoring campaign. Possible reasons for uneven distribution were explored and recommendations are made to address the uniformity issue. The findings from the study are expected to further the development and implementation of biofiltration technology for livestock odor control.

12

Sane, S. P. "Induced airflow in flying insects II. Measurement of induced flow". Journal of Experimental Biology 209, n. 1 (1 gennaio 2006): 43–56. http://dx.doi.org/10.1242/jeb.01958.

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13

Kolbe, Sven, Manuel Mohr, Martin Maier, Laurin Osterholt, Barry Gardiner e Dirk Schindler. "On the Potential of Using Air Pressure Fluctuations to Estimate Wind-Induced Tree Motion in a Planted Scots Pine Forest". Forests 13, n. 2 (2 febbraio 2022): 225. http://dx.doi.org/10.3390/f13020225.

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This paper reports statistical relationships between measured airflow, air pressure fluctuations, and the wind-induced motion of planted Scots pine trees (Pinus sylvestris L.). The results presented illustrate the potential of low-cost, ground-based air pressure measurements for monitoring wind-induced tree response. It is suggested that air pressure fluctuations can be used as surrogate information for above-canopy airflow, often used to estimate wind loads on forest trees. We demonstrate that air pressure fluctuations can be measured representatively at the forest floor and correlate very well with wind speed and direction at mean canopy-top (18 m a.g.l.) and above the 18 m high, 56-year-old forest. Their strong correlation (coefficient of determination R2 > 0.77) allows a good approximation of airflow conditions above the canopy, and, with some limitations, in the below-canopy space. Air pressure fluctuations also correlate very well with wind-induced tree motion with a similar correlation to that between wind speed and tree motion. Furthermore, the main directions of wind-induced tree motion agree very well with the propagation direction of air pressure waves. Above-canopy airflow measurements in forests with a large vertical extent are rare, and often require tall wind measurement towers. Therefore, we consider the estimation of airflow conditions over forests using ground-based air pressure measurements a promising option for monitoring the airflow conditions of relevance for predicting wind-induced tree response over large areas using a minimum of measurement infrastructure.

14

Haiyi Sun, Haiyi Sun, Yonghong Liu Yonghong Liu, Jiansheng Liu Jiansheng Liu, Jingjing Ju Jingjing Ju, Cheng Wang Cheng Wang, Xingkai Hu Xingkai Hu, Zhongbin Zhu Zhongbin Zhu et al. "Sub-picosecond chirped laser pulse-induced airflow and water condensation in a cloud chamber". Chinese Optics Letters 16, n. 6 (2018): 061403. http://dx.doi.org/10.3788/col201816.061403.

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15

Chinchella, Enrico, Arianna Cauteruccio, Mattia Stagnaro e Luca G. Lanza. "Investigation of the Wind-Induced Airflow Pattern Near the Thies LPM Precipitation Gauge". Sensors 21, n. 14 (17 luglio 2021): 4880. http://dx.doi.org/10.3390/s21144880.

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The airflow velocity pattern generated by a widely used non-catching precipitation gauge (the Thies laser precipitation monitor or LPM) when immersed in a wind field is investigated using computational fluid dynamics (CFD). The simulation numerically solves the unsteady Reynolds-averaged Navier–Stokes (URANS) equations and the setup is validated against dedicated wind tunnel measurements. The adopted k-ω shear stress transport (SST) turbulence model closely reproduces the flow pattern generated by the complex, non-axisymmetric outer geometry of the instrument. The airflow pattern near the measuring area varies with the wind direction, the most intense recirculating flow and turbulence being observed when the wind blows from the back of the instrument. Quantitative parameters are used to discuss the magnitude of the airflow perturbations with respect to the ideal configuration where the instrument is transparent to the wind. The generated airflow pattern is expected to induce some bias in operational measurements, especially in strong wind conditions. The proposed numerical simulation framework provides a basis to develop correction curves for the wind-induced bias of non-catching gauges, as a function of the undisturbed wind speed and direction.

16

Li, Zhipeng, Jinghao Li e Hejuan Chen. "Experimental Research on Excitation Condition and Performance of Airflow-Induced Acoustic Piezoelectric Generator". Micromachines 11, n. 10 (30 settembre 2020): 913. http://dx.doi.org/10.3390/mi11100913.

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This paper aims to present a novel airflow-induced acoustic piezoelectric generator that can be used to solve the problem of insufficient power supply of modern intelligent fuzes. The sound waves induced by airflow are the key to power generation performance. It is proposed that an edge tone frequency equal to the acoustic mode frequency is a sufficient condition for evoked acoustic waves, and a design idea and scheme for a universal fuze power supply is provided. We establish the vibration model of the airflow-induced acoustic piezoelectric generator. According to the model, the experimental research on the power generation performance shows that the sound pressure frequency, vibration displacement frequency, and output voltage frequency are consistent. The model provides a design idea for a vibration sensor. At the flow rate of 100.8 m/s, the output power is 45.3 mW, which is much higher than the fuze power sources such as the magnetic backseat generator. Therefore, the airflow-induced piezoelectric generator can effectively solve the problem of the modern fuze less types of power supply and low output energy.

17

Haas, F., S. Pasierski, N. Levine, M. Bishop, K. Axen, H. Pineda e A. Haas. "Effect of aerobic training on forced expiratory airflow in exercising asthmatic humans". Journal of Applied Physiology 63, n. 3 (1 settembre 1987): 1230–35. http://dx.doi.org/10.1152/jappl.1987.63.3.1230.

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Pulmonary function after exercise was evaluated in 22 asthmatic subjects before and after a 36-session training sequence of aerobic exercise. Training did not change pulmonary function values, except for a small increase in maximal voluntary ventilation (P less than 0.02), which was attributed to respiratory muscle training. After aerobic training, both external work at a given heart rate and peak O2 consumption increased by 30 and 15%, respectively. At the same minute ventilation (VE), immediate postexercise forced expiratory airflow was higher after training (P less than 0.02), and reduction in forced expiratory airflow during the first 9 min postexercise was less after training (P less than 0.01). The posttraining airflow response to the pretraining work load was, as expected, less than the pretraining response (P less than 0.02). Although the difference in maximal-to-minimal airflow at the same VE was similar before and after training, the airflow increase accounted for 50% of the response after training compared with 16% of the pretraining response. Furthermore the strong negative correlation (P less than 0.01) between maximal and minimal airflow both pre- and posttraining indicates that exercise-induced bronchospasm (EIB) severity is, in part, determined by the degree of exercise-induced bronchodilation. We conclude that aerobic training significantly increases exercise-induced bronchodilation and diminishes EIB.

18

Li, Hu, Hong Han, Xinjin Liu, Shujing Chen, Jingqian Wang e Wenjun Lei. "Effects of Train-Induced Unsteady Airflow on Air Quality and Air Distribution in a Subway Station". Buildings 12, n. 12 (1 dicembre 2022): 2114. http://dx.doi.org/10.3390/buildings12122114.

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Using train-induced unsteady airflow in transitional seasons can greatly reduce the energy consumption of a subway station’s mechanical ventilation. However, the unsteady airflow carries the particles from tunnels into subway platforms, and airflow distribution at controllable vents is uneven. To determine the variation in PM2.5 (particulate matter of 2.5 micrograms or less) concentration and the air velocity distribution at the vents, field tests were conducted. The results showed that the PM2.5 concentrations at the vents and platform were positively correlated with the air velocity. The average ratio of the PM2.5 concentration at the vents to that on the platform was 71.15%. The maximum PM2.5 concentration and average PM2.5 concentration on the platform were 0.067 mg/m3 and 0.037 mg/m3, respectively. The air velocity distribution along the length of the platform conformed to logistic regression. Adjustment of the opening height of the vents was proposed to improve the air velocity distribution. Through numerical simulation, the ratio of the minimum airflow rate to the maximum airflow rate was increased from 5.9% to 37.5% after adjustment. This method is helpful for the uniform distribution of the airflow rate. This study will provide references for the design and operation of the vents of subway stations.

19

Guo, Hengyu, Jie Chen, Li Tian, Qiang Leng, Yi Xi e Chenguo Hu. "Airflow-Induced Triboelectric Nanogenerator as a Self-Powered Sensor for Detecting Humidity and Airflow Rate". ACS Applied Materials & Interfaces 6, n. 19 (17 settembre 2014): 17184–89. http://dx.doi.org/10.1021/am504919w.

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Teeter, JG, e AN Freed. "Effect of salbutamol on dry air- and acetylcholine-induced bronchoconstriction in the canine lung periphery". European Respiratory Journal 4, n. 8 (1 settembre 1991): 972–78. http://dx.doi.org/10.1183/09031936.93.04080972.

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We examined the effect of salbutamol on dry airflow-induced bronchoconstriction (AIB) and acetylcholine-induced bronchoconstriction (Ach-IB) in the canine lung periphery using a wedged bronchoscope technique. Collateral system resistance (Rcs) and airway wall temperature (Taw) were monitored in a peripheral lung segment before, during and after airflow challenge. Rcs before and after aerosolized acetylcholine was recorded in a contralateral lung segment. Intravenous salbutamol (2.5 micrograms.kg-1) significantly attenuated the peak fall in Taw during airflow challenge and the peak rise in Rcs following challenge. Intravenous salbutamol attenuated Ach-IB to a similar degree. Significant systemic effects were recorded following i.v. salbutamol. In contrast, aerosolized salbutamol (50 micrograms) minimally decreased the fall in Taw during airflow challenge, while virtually eliminating AIB. The same dose of aerosolized salbutamol only partially attenuated Ach-IB. Aerosolized salbutamol did not affect mean arterial pressure or heart rate. Intravenous salbutamol may in part inhibit AIB by increasing pulmonary blood flow, secondary to its systemic circulatory effects, and decrease heat and water loss during airflow challenge. In contrast, aerosolized salbutamol abolished AIB, while only minimally effecting airway cooling. These data suggest that AIB is a result of mediator release and/or smooth muscle contraction.

21

Popov, E. N. "Definition of airflow rate induced by polifractional materials". IOP Conference Series: Materials Science and Engineering 327 (marzo 2018): 042084. http://dx.doi.org/10.1088/1757-899x/327/4/042084.

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22

Mestrom, R. M. C., R. H. B. Fey, H. Nijmeijer, P. M. R. Wortelboer e W. Aerts. "Airflow-Housing-Induced Resonances of Rotating Optical Disks". Journal of Applied Mechanics 74, n. 6 (16 marzo 2007): 1252–63. http://dx.doi.org/10.1115/1.2745356.

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Numerous excitation sources for disk vibrations are present in optical drives. For increasing rotation speeds, airflow-housing-induced vibrations have become more and more important. Currently, drives are designed in which rotation speeds are so high that critical speed resonances may show up. The presence of these resonances depends on the layout of the inner housing geometry of the drive. The influence of the drive inner housing geometry is investigated systematically by means of a numerical-experimental approach. An analytical model is derived, containing disk dynamics and the geometry-induced pressure distribution acting as the excitation mechanism on the disk. The Reynolds’ lubrication equation is used as a first approach for the modeling of the pressure distribution. The model is numerically implemented using an approach based on a combination of finite element and finite difference techniques. An idealized, drive-like environment serves as the experimental setup. This setup resembles the situation in the numerical model, in order to be able to verify the numerical model. Wedge-like airflow disturbances are used in order to obtain insight into the influence of drive inner geometry on the critical speed resonances of optical disks. A disk tilt measurement method is designed that yields a global view of the disk deformation. By means of two newly proposed types of plots, numerical and experimental results can be compared in a straightforward way. A qualitative match between the numerical and experimental results is obtained. The numerical and experimental methods presented provide insight into airflow-housing-induced vibrations in optical drives. Additionally, reduction of some critical speed resonances is found to be possible for certain drive inner geometry configurations.

23

SZCZEKLIK, A., E. NIZANKOWSKA, G. CZERNIAWSKAMYSIK e S. SK. "Hydrocortisone and airflow impairment in aspirin-induced asthma". Journal of Allergy and Clinical Immunology 76, n. 4 (ottobre 1985): 530–36. http://dx.doi.org/10.1016/0091-6749(85)90771-7.

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24

Lee, Chia Yen, Yu Hsiang Wang, Tzu Han Hsueh, Rong Hua Ma, Lung Ming Fu e Po Cheng Chou. "A Smart Flow Sensor for Flow Direction Measurement". Advanced Materials Research 47-50 (giugno 2008): 189–92. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.189.

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The purpose of this paper is to apply MEMS techniques to manufacture a gas flow sensor that consists with an airflow rate and airflow direction sensing units for detection of airflow states. This study uses a silicon wafer as a substrate which is deposited silicon nitride layers. To form the airflow rate sensing unit, a micro heater and a sensing resistor are manufactured over a membrane that released by a back-etching process. The airflow direction sensing unit is made of four cantilever beams that perpendicular to each other and integrated with piezoresistive structure on each micro-cantilever, respectively. As the cantilever beams are formed after etching the silicon wafer, it bends up a little due to the released residual stress induced in the previous fabrication process. As air flows through the airflow rate sensor, the temperature of the sensing resistor decreases and the evaluation of the local temperature changes determines the airflow rate. On the proposed sensor, the airflow direction can be determined through comparing the resistance variation caused by different deformation of cantilever beams at different directions.

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Freed, A. N., D. Wang e H. A. Menkes. "Dry air-induced constriction: effects of pharmacological intervention and temperature". Journal of Applied Physiology 62, n. 5 (1 maggio 1987): 1794–800. http://dx.doi.org/10.1152/jappl.1987.62.5.1794.

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We studied airway wall temperature (Taw) during dry air challenge of the canine lung periphery. We measured collateral resistance (Rcs) before and after periods of elevated airflow using a wedged bronchoscope technique. As flow rate increased, Taw dropped and postchallenge Rcs rose. A significant negative correlation was found between Taw recorded during challenge and Rcs observed 5 min after challenge. Repetitive dry air challenge produced similar changes in Rcs and Taw. However, responses to warm moist air were significantly lower than consecutive responses to dry air. Taw was significantly lower during dry air challenge than during moist air challenge. Indomethacin (5 mg/kg) and atropine (1 mg/kg) reduced responses to dry airflow challenge. Indomethacin did not affect Taw during the challenge, whereas atropine reduced the fall in Taw. We conclude that temperature correlates negatively with peripheral lung tone 5 min after dry air challenge. This correlation holds under conditions where airflow is increased, air is humidified, or atropine is administered. The dissociation between Taw and physiological response after indomethacin likely reflects a decrease in mediators released during challenge.

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Freed, A. N., S. P. Peters e H. A. Menkes. "Airflow-induced bronchoconstriction: role of epithelium and eicosanoid mediators". Journal of Applied Physiology 62, n. 2 (1 febbraio 1987): 574–81. http://dx.doi.org/10.1152/jappl.1987.62.2.574.

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We examined the role of cyclooxygenase-derived metabolites and epithelial cells in airflow-induced bronchospasm. Male dogs were anesthetized and collateral system resistance (Rcs) was measured with the wedged-bronchoscope technique. A 2-min high flow challenge with dry air in nine animals produced a mean increase in Rcs of 69 +/- 13% (SE). After treatment with indomethacin (5 mg/kg), the response was significantly attenuated; Rcs increased only 40 +/- 8%. Bronchoalveolar lavage performed 5 min after a dry air challenge yielded fluid with greater concentrations of prostaglandin D2 (PGD2) and thromboxane B2 than samples from unchallenged segments. Challenge with humidified air produced a smaller physiological response than did challenge with dry air. Lavage samples obtained after dry challenge had greater concentrations of PGD2 than samples taken after challenge with humidified air. After dry air challenge, epithelial cells in lavage fluid were increased by 454 and 515% when compared with control and humidified air challenge, respectively. Significant correlations were found between epithelial cell number and PGD2 recovered in lavage fluid after dry air challenges. We conclude that both epithelial cells and prostaglandins play an important role in peripheral lung responses to dry air.

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Fu, H., R. Xu, K. Seto, E. M. Yeatman e S. G. Kim. "Energy Harvesting from Human Motion Using Footstep-Induced Airflow". Journal of Physics: Conference Series 660 (10 dicembre 2015): 012060. http://dx.doi.org/10.1088/1742-6596/660/1/012060.

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Pellegrino, R., B. Violante, S. Nava, C. Rampulla, V. Brusasco e J. R. Rodarte. "Expiratory airflow limitation and hyperinflation during methacholine-induced bronchoconstriction". Journal of Applied Physiology 75, n. 4 (1 ottobre 1993): 1720–27. http://dx.doi.org/10.1152/jappl.1993.75.4.1720.

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To investigate the role of airflow limitation on the increase of end-expiratory lung volume (EELV) during bronchoconstriction, nine stable asthmatic subjects and seven healthy subjects were challenged with inhaled methacholine (MCh). Changes in airway caliber were assessed by using forced expiratory volume in 1 s, partial forced expiratory flow at 50% of control forced vital capacity, and specific airway conductance. To detect airflow limitation, tidal flow-volume curves were superimposed on partial forced flow-volume curves at absolute lung volume. The electromyogram of the diaphragm was recorded by surface electrodes in four asthmatic and four healthy subjects, and the electrical diaphragmatic activity (DIA) during expiration was expressed as a percentage of the duration of expiratory time. In 10 subjects (9 asthmatic and 1 healthy) the partial forced expiratory flow recorded after some MCh dose impinged on tidal expiratory flow recorded before MCh. When this occurred it was associated with an increase in EELV by 0.54 +/- 0.07 (SE) liter (P < 0.001), which was larger than that occurring when lower MCh doses (0.11 +/- 0.04 liter, P < 0.05) were used, and with a moderate increase in DIA of 15 +/- 2.5% (P < 0.01). Six healthy subjects did not increase EELV after MCh despite a significant degree of bronchoconstriction; in these subjects tidal expiratory flow never impinged on forced expiratory flow, and DIA never increased. These results suggest that hyperinflation during MCh-induced bronchoconstriction is triggered by dynamic compression of the airways and is associated with moderate increase of DIA during expiration.

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NIZANKOWSKA, E., G. CZERNIAWSKAMYSIK, J. DREWNIAK e A. SZCZEKLIK. "215 Hydrocortisone and airflow impairment in aspirin-induced asthma". Journal of Allergy and Clinical Immunology 75, n. 1 (gennaio 1985): 158. http://dx.doi.org/10.1016/0091-6749(85)90350-1.

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Hosaka, Hiroshi, e Kiyoshi Itao. "Coupled Vibration of Microcantilever Array Induced by Airflow Force". Journal of Vibration and Acoustics 124, n. 1 (1 luglio 2001): 26–32. http://dx.doi.org/10.1115/1.1421054.

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The coupled vibrations of microcantilevers induced by airflow were analyzed to facilitate the development of high-speed information and sensing devices that use microactuator arrays. Simple formulas, from which the vibrational coupling amplitude and damping ratio can be obtained, are derived by replacing the cantilevers with strings of spheres, solving Stokes equation, and combining this with an ordinary beam equation. The coupling amplitude was found to increase as the beam size, beam gap, internal friction, and the difference in the resonant frequencies of the beams decreased and the damping ratio increased as the beam size was reduced. The validity of the theory is verified with actual-size and enlarged model experiments.

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Huang, Yong, Xin Zhang, Xun-Nian Wang, Wan-Bo Wang, Zong-Bo Huang e Hua-Xing Li. "Experimental Investigation of the Induced Airflow of Corona Discharge". Chinese Physics Letters 30, n. 9 (settembre 2013): 094702. http://dx.doi.org/10.1088/0256-307x/30/9/094702.

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32

O'Donnell, Anne E. "Exercise-induced Airflow Obstruction in a Healthy Military Population". Chest 103, n. 3 (marzo 1993): 742–44. http://dx.doi.org/10.1378/chest.103.3.742.

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33

Tamura, Hitoshi, William M. Drennan, Clarence O. Collins e Hans C. Graber. "Turbulent Airflow and Wave-Induced Stress Over the Ocean". Boundary-Layer Meteorology 169, n. 1 (28 maggio 2018): 47–66. http://dx.doi.org/10.1007/s10546-018-0359-1.

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34

Fan, Chaonan, Qingjie Qi, Xi Chen e Shaocheng Ge. "Study on the characteristics of induced airflow and particle dispersion based on the multivariate two-factor model". PLOS ONE 17, n. 2 (8 febbraio 2022): e0263740. http://dx.doi.org/10.1371/journal.pone.0263740.

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Abstract (sommario):

To examine the diffusion characteristics of airflow and dust particles, a multi-factor and multi-level physical self-developed testing system is established. In this study, bunker height, chute angle, feeding speed, coal granularity, and belt speed are selected as independent variables, and airflow velocity and dust concentration are the response variables. The two-factor interactive model is established to analyze the primary and secondary relationship between the independent variables and the response variables. The results demonstrate a denser contour distribution of three-dimensional curved surfaces, suggesting an obvious interaction between the factors. The bunker height increases from 0.75 m to 1.15 m, the maximum increment of the induced airflow velocity at the outlet of the guide chute is observed to be 0.35 m/s, meanwhile, and with the increase in the feed speed from 2t/h to 8t/h, the increment of the induced airflow velocity at the outlet of the guide chute is recorded to be 51%. The coal granularity and bunker height depicted the highest influence on induced air velocity and dust concentration, and the feeding speed proved to be the secondary parameter. This two-factor interactive model can accurately forecast the actual values with a deviation of the calculated values limited to 9%. These research results support the existing research and provide a theoretical foundation to guide the dust control at belt conveyor transfer stations.

35

Yan, Xiaonan, Liangliang Tao, Junqin Peng, Yanhua Zeng, Yong Fang e Yun Bai. "Behavior of Piston Wind Induced by Braking Train in a Tunnel". Energies 13, n. 23 (4 dicembre 2020): 6420. http://dx.doi.org/10.3390/en13236420.

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It is critical to discover the behavior of piston wind induced by a braking train in a tunnel, but there is little research on the theoretical derivation for piston wind behavior. Predicting piston wind behavior as an unsteady airflow by a theoretical formula is hard work due to the complexity of train running states and airflow fields. Herein, we develop a mathematical model to investigate the behavior of piston wind as an unsteady airflow, considering the variation of wind direction in the annular area. In general, the theoretical model is validated by experiments. However, experimental studies about piston wind are scarce. In this study, we simulated the emergent braking process of a train to validate the mathematical model by establishing a 1/50 scaled experimental configuration. The piston wind data tested in the experiment have good agreement with the results calculated by theoretical formulas. In addition, sensitivity analysis of the effect parameters of piston wind (i.e., tunnel length, train length, train speed and blockage ratio) was conducted. The theoretical formulas derived in this paper are applicable to similar train running conditions in railway tunnels or subway tunnels.

36

Satia, Imran, Eldar Priel, Baraa K. Al-Khazraji, Graham Jones, Andy Freitag, Paul M. O'Byrne e Kieran J. Killian. "Exercise-induced bronchoconstriction and bronchodilation: investigating the effects of age, sex, airflow limitation and FEV1". European Respiratory Journal 58, n. 2 (14 gennaio 2021): 2004026. http://dx.doi.org/10.1183/13993003.04026-2020.

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Exercise-induced bronchoconstriction (EIBc) is a recognised response to exercise in asthmatic subjects and athletes but is less well understood in an unselected broad population. Exercise-induced bronchodilation (EIBd) has received even less attention. The objective of this study was to investigate the effects of age, sex, forced expiratory volume in 1 s (FEV1) and airflow limitation (FEV1/forced vital capacity (FVC) <0.7) on the prevalence of EIBc and EIBd.This was a retrospective study based on incremental cardiopulmonary exercise testing on cycle ergometry to symptom limitation performed between 1988 and 2012. FEV1 was measured before and 10 min after exercise. EIBc was defined as a percentage fall in FEV1 post-exercise below the 5th percentile, while EIBd was defined as a percentage increase in FEV1 above the 95th percentile.35 258 subjects aged 6–95 years were included in the study (mean age 53 years, 60% male) and 10.3% had airflow limitation (FEV1/FVC <0.7). The lowest 5% of subjects demonstrated a ≥7.6% fall in FEV1 post-exercise (EIBc), while the highest 5% demonstrated a >11% increase in FEV1 post-exercise (EIBd). The probability of both EIBc and EIBd increased with age and was highest in females across all ages (OR 1.76, 95% CI 1.60–1.94; p<0.0001). The probability of EIBc increased as FEV1 % pred declined (<40%: OR 4.38, 95% CI 3.04–6.31; p<0.0001), with a >2-fold increased likelihood in females (OR 2.31, 95% CI 1.71–3.11; p<0.0001), with a trend with airflow limitation (p=0.06). The probability of EIBd increased as FEV1 % pred declined, in the presence of airflow limitation (OR 1.55, 95% CI 1.24–1.95; p=0.0001), but sex had no effect.EIBc and EIBd can be demonstrated at the population level, and are influenced by age, sex, FEV1 % pred and airflow limitation.

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Chen, Bohao, Gustine Liu, Felix Shardonofsky, Maria Dowell, Oren Lakser, Richard W. Mitchell, Jeffrey J. Fredberg, Lawrence H. Pinto e Julian Solway. "Tidal breathing pattern differentially antagonizes bronchoconstriction in C57BL/6J vs. A/J mice". Journal of Applied Physiology 101, n. 1 (luglio 2006): 249–55. http://dx.doi.org/10.1152/japplphysiol.01010.2004.

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There is abundant evidence that tidal breathing, and especially tidal breathing at elevated minute ventilation, antagonizes the development and persistence of airflow obstruction during bronchoconstrictor stimulation in normal animals and people. Here, we studied the antiobstructive effect of different tidal breathing patterns in C57Bl/6J and A/J mice during bronchoconstriction induced by continuous or bolus infusion of methacholine. Anesthetized, paralyzed mice were mechanically ventilated at 1,500 ml·kg−1·min−1, using each of three breathing patterns: 5 ml/kg, 300 breath/min; 10 ml/kg, 150 breath/min; or 20 ml/kg, 75 breath/min. Changing from 10 ml/kg, 150 breath/min to 20 ml/kg, 75 breath/min, breathing functionally antagonized bronchoconstriction, reducing the level of airflow obstruction induced by methacholine infusion or boluses equivalently in both strains. In marked contrast, changing from 10 ml/kg, 150 breath/min to 5 ml/kg, 300 breath/min, breathing substantially exacerbated methacholine-induced airflow obstruction in A/J mice, whereas it had no significant effect in C57Bl/6J mice. Our results therefore demonstrate that 1) even at moderate, fixed minute ventilation, the precise breathing pattern can influence the degree of airflow obstruction substantially, and 2) the influence of breathing pattern on bronchoconstriction differs considerably between genetically diverse inbred mouse strains. These findings imply that differences in antiobstructive effects of breathing can contribute to differences in apparent airway constrictor responsiveness. Much attention has been placed on dysregulation of contractile function of airway smooth muscle in human disease. We suggest that important pathophysiology might also be found in impairment of the functional antagonist effect of tidal breathing on airflow obstruction.

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Lin, Wu Zhong, Feng Gao e Eng Hong Ong. "DVM-13 AIRFLOW INDUCED VIBRO-ACOUSTICS ANALYSIS OF HDD(Drive Mechanisms IV,Technical Program of Oral Presentations)". Proceedings of JSME-IIP/ASME-ISPS Joint Conference on Micromechatronics for Information and Precision Equipment : IIP/ISPS joint MIPE 2009 (2009): 237–38. http://dx.doi.org/10.1299/jsmemipe.2009.237.

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39

Sane, S. P. "Induced airflow in flying insects I. A theoretical model of the induced flow". Journal of Experimental Biology 209, n. 1 (1 gennaio 2006): 32–42. http://dx.doi.org/10.1242/jeb.01957.

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40

Grare, Laurent, Luc Lenain e W. Kendall Melville. "Wave-Coherent Airflow and Critical Layers over Ocean Waves". Journal of Physical Oceanography 43, n. 10 (1 ottobre 2013): 2156–72. http://dx.doi.org/10.1175/jpo-d-13-056.1.

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Abstract An analysis of coherent measurements of winds and waves from data collected during the Office of Naval Research (ONR) High-Resolution air–sea interaction (HiRes) program, from the Floating Instrument Platform (R/P FLIP), off the coast of northern California in June 2010 is presented. A suite of wind and wave measuring systems was deployed to resolve the modulation of the marine atmospheric boundary layer by waves. Spectral analysis of the data provided the wave-induced components of the wind velocity for various wind–wave conditions. The power spectral density, the amplitude, and the phase (relative to the waves) of these wave-induced components are computed and bin averaged over spectral wave age c/U(z) or c/u*, where c is the linear phase speed of the waves, U(z) is the mean wind speed measured at the height z of the anemometer, and u* is the friction velocity in the air. Results are qualitatively consistent with the critical layer theory of Miles. Across the critical height zc, defined such that U(zc) = c, the wave-induced vertical and horizontal velocities change significantly in both amplitude and phase. The measured wave-induced momentum flux shows that, for growing waves, less than 10% of the momentum flux at z ≈ 10 m is supported by waves longer than approximately 15 m. For older sea states, these waves are able to generate upward wave-induced momentum flux opposed to the overall downward momentum flux. The measured amplitude of this upward wave-induced momentum flux was up to 20% of the value of the total wind stress when Cp/u* > 60, where Cp is the phase speed at the peak of the wave spectrum.

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Sun, Jie, e Min Li. "Effects of motion-induced aerodynamic force on the performance of active buffeting control". Journal of Vibroengineering 18, n. 2 (31 marzo 2016): 951–64. http://dx.doi.org/10.21595/jve.2016.16237.

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During buffeting control of an aircraft, there consequently is a motion-induced aerodynamic force. However, it is not yet clear whether this additional force must be considered in design of control law. In this paper, to hopefully answer this interesting question, effects of the motion-induced aerodynamic force on the active buffeting control during control law design are studied. The macro fiber composite (MFC) actuator is modeled by employing the load simulation method, and the motion-induced unsteady aerodynamic forces are computed by the doublet-lattice method. Two different controllers, i.e. one with the motion-induced aerodynamic force and another without it, are simultaneously designed based on the linear quadratic Gaussian (LQG) control method. And, two corresponding models are respectively developed. Then, the control effects of the two models are compared and the physical mechanisms are discussed. From our simulation results it is found that the motion-induced aerodynamic forces do influence the buffeting responses depending on airflow velocity. The differences of the control effects of the two models are smaller at lower airflow velocity below the flutter velocity, however with the increase of the airflow velocity the control effect of the model considering the motion-induced aerodynamic force is much better. The larger the velocity is, the more significant the differences are. Finally, the energy dissipation of the motion-induced aerodynamic force is examined and found to be a main factor influencing the differences of the two models.

42

Viani, Laura, Andrew S. Jones e Ray Clarke. "Nasal airflow in inspiration and expiration". Journal of Laryngology & Otology 104, n. 6 (giugno 1990): 473–76. http://dx.doi.org/10.1017/s0022215100112915.

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AbstractInspiratory and expiratory airflow rates were measured in 30 subjects during quiet respiration (at a pressure gradient of 150 Pa) and at peak flow rates.For low flow rates airflow rate was greater for inspiration than for expiration. Conversely at peak flow rates flow was greatest during expiration. Thus there was a reversal in the phase relationship between inspiration and expiration as flow rate increased.It was also found that peak inspiratory flow rate correlated better with values for nasal resistance than did peak expiratory flow rate. Flow rate measured by rhinomanometry during quiet respiration was more sensitive to physiologically induced changes in nasal resistance than was peak flow rate.The findings are discussed with reference to previous work on the physiology of nasal airflow.

43

Sun, Ke, Lin Lu e Yu Jiang. "Analysis of orientation and tensor properties of airborne fibrous particle flow". International Journal of Numerical Methods for Heat & Fluid Flow 24, n. 8 (28 ottobre 2014): 1795–802. http://dx.doi.org/10.1108/hff-04-2013-0118.

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Purpose – The purpose of this paper is to study the effect of particle shapes (spherical particle and nonspherical fiber) on their orientation distributions in indoor environment. Design/methodology/approach – This paper adopted a particle model to predict the fibrous particle flow and distribution, and analyzed the orientation distributions of nonspherical fiber particles and spherical particles in airflows like indoor places. Fokker-Planck model was employed to solve the orientation behavior of nonspherical fiber particles. Findings – The simulation results discover that the nonspherical airborne fiber particles have very different characteristics and behaviors and their orientation distributions are totally different from the uniform distribution of spherical particles. The investigation of the particle orientation tensor and orientation strength indicates that the airflow field becomes more anisotropic due to the suspended fibers. The airborne fiber particles increase the viscosity of the room airflow due to the fiber induced additional viscosity. Originality/value – Orientation tensor, strength and additional viscosity in fibrous flow are seldom investigated indoor. This research reveals that the particle shape has to be considered in the analysis of particle transport and distribution in indoor places as most suspended indoor particles are nonspherical.

44

Baehr, Arthur L., e Craig J. Joss. "An Updated Model of Induced Airflow in the Unsaturated Zone". Water Resources Research 31, n. 2 (febbraio 1995): 417–21. http://dx.doi.org/10.1029/94wr02423.

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45

Freed, Arthur N., Laurie J. Kelly e Harold A. Menkes. "Airflow-induced Bronchospasm: Imbalance between Airway Cooling and Airway Drying?" American Review of Respiratory Disease 136, n. 3 (agosto 1987): 595–99. http://dx.doi.org/10.1164/ajrccm/136.3.595.

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46

Kirschvink, Nathalie, Jérôme Leemans, François Delvaux, Fréderic Snaps, Cécile Clercx e Pascal Gustin. "Bronchodilators in Bronchoscopy-Induced Airflow Limitation in Allergen-Sensitized Cats". Journal of Veterinary Internal Medicine 19, n. 2 (marzo 2005): 161–67. http://dx.doi.org/10.1111/j.1939-1676.2005.tb02677.x.

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47

Gutiérrez, G., L. I. Reyes, I. Sánchez, K. Rodríguez, V. Idler e R. Paredes V. "Vibration induced airflow through granular beds and density-dependent segregation". Physica A: Statistical Mechanics and its Applications 356, n. 1 (ottobre 2005): 83–87. http://dx.doi.org/10.1016/j.physa.2005.05.017.

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48

Wu, Yimeng, Xuemin Lu e Qinghua Lu. "Airflow-induced nanochannel orientation in mesoporous polymers and carbon films". Microporous and Mesoporous Materials 211 (luglio 2015): 152–57. http://dx.doi.org/10.1016/j.micromeso.2015.03.004.

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49

Kuang, Xingxing, Jiu Jimmy Jiao e Hailong Li. "Review on airflow in unsaturated zones induced by natural forcings". Water Resources Research 49, n. 10 (ottobre 2013): 6137–65. http://dx.doi.org/10.1002/wrcr.20416.

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50

Fuller, SD, e AN Freed. "No influence of airway heat flux on airflow-induced bronchospasm". European Respiratory Journal 5, n. 6 (1 giugno 1992): 707–11. http://dx.doi.org/10.1183/09031936.93.05060707.

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Abstract (sommario):

We used a canine model of airway reactivity to examine the role of airway heat flux in the response to dry air challenge. Airflow-induced bronchospasm (AIB) was assessed by measuring collateral system resistance (Rcs) with a wedged bronchoscope technique in anaesthetized mechanically ventilated dogs. We manipulate post-challenge airway heat flux by exposing peripheral airways to cool dry air (23.9 +/- 0.3 degrees C, 0.8 +/- 0.2 mgH2O.l-1), cool humid air (24.2 +/- 0.2 degrees C, 21.5 +/- 0.3 mgH2O.l-1), or warm humid air (35.3 +/- 0.4 degrees C, 40.6 +/- 0.3 mgH2O.l-1) during the recovery period (n = 14) following a high flow challenge (1,500 ml.min-1 for 2 min) with cool dry air. In a second series of experiments (n = 6), we attempted to further exaggerate airway heat flux during challenge by exposing peripheral airways to warm humid air during both baseline and recovery periods. In comparison to control (i.e. treatment with cool dry air before and after challenge), treatment with warm humid air during recovery period produced a small but significant attenuation (p less than 0.01) in Rcs. Cool humid air during recovery had no affect on Rcs following challenge. Warm humid air during both baseline and recovery tended to attenuate Rcs after challenge (p less than 0.05). We conclude that airway heat flux in itself has no significant physiological affect on AIB in the canine lung periphery.

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