Respiratory phase detection and delay determination for breath-by-breath analysis

1987 ◽  
Vol 62 (2) ◽  
pp. 837-843 ◽  
Author(s):  
U. Boutellier ◽  
T. Kundig ◽  
U. Gomez ◽  
P. Pietsch ◽  
E. A. Koller
Keyword(s):  
Ambient Air ◽  
Phase Detection ◽  
Breathing Patterns ◽  
Test Gas ◽  
Gas Concentration ◽  
Threshold Criterion ◽  
Respiratory Phase ◽  
Valve Assembly ◽  
Delay Variations ◽  
The Moment

The delay between air flow and gas concentration signals is generally assumed to be constant within a breath as well as from breath to breath, but it was not possible to examine the constancy of the delay with the delay determination techniques so far available. Thus we developed new methods for respiratory phase detection and delay determination. The presented algorithm for the detection of the start of inspiration and expiration (phase detection) replaces the generally used valve assembly with two pneumotachographs. Now, the pneumotachograph is used in a bidirectional mode, but with a volume criterion for phase detection replacing the less reliable threshold criterion. To measure the delay between flow and gas concentration signals, a test gas is periodically injected as a marker. This test gas contains less N2 than ambient air. Therefore, the delay is determined as time between the moment of injection and the drop of N2. These two methods rendered it possible to examine delay variations and their consequences. The investigation of various breathing patterns demonstrated that the usually assumed errors caused by delay uncertainty are underestimated. We suggest reliance on a breath-by-breath delay determination to account for delay variations.

scholarly journals Vortex and half-vortex dynamics in a nonlinear spinor quantum fluid

2015 ◽  
Vol 1 (11) ◽  
pp. e1500807 ◽  
Author(s):  
Lorenzo Dominici ◽  
Galbadrakh Dagvadorj ◽  
Jonathan M. Fellows ◽  
Dario Ballarini ◽  
Milena De Giorgi ◽  
...  
Keyword(s):  
Vortex Dynamics ◽  
Strong Nonlinearity ◽  
Phase Detection ◽  
Ultrafast Imaging ◽  
Half Integer ◽  
Fundamental Particles ◽  
Subatomic Particles ◽  
Phase Singularities ◽  
The Moment ◽  
Bose Einstein

Vortices are archetypal objects that recur in the universe across the scale of complexity, from subatomic particles to galaxies and black holes. Their appearance is connected with spontaneous symmetry breaking and phase transitions. In Bose-Einstein condensates and superfluids, vortices are both point-like and quantized quasiparticles. We use a two-dimensional (2D) fluid of polaritons, bosonic particles constituted by hybrid photonic and electronic oscillations, to study quantum vortex dynamics. Polaritons benefit from easiness of wave function phase detection, a spinor nature sustaining half-integer vorticity, strong nonlinearity, and tuning of the background disorder. We can directly generate by resonant pulsed excitations a polariton condensate carrying either a full or half-integer vortex as initial condition and follow their coherent evolution using ultrafast imaging on the picosecond scale. The observations highlight a rich phenomenology, such as the spiraling of the half-vortex and the joint path of the twin charges of a full vortex, until the moment of their splitting. Furthermore, we observe the ordered branching into newly generated secondary couples, associated with the breaking of radial and azimuthal symmetries. This allows us to devise the interplay of nonlinearity and sample disorder in shaping the fluid and driving the vortex dynamics. In addition, our observations suggest that phase singularities may be seen as fundamental particles whose quantized events span from pair creation and recombination to 2D+t topological vortex strings.

Computerised acoustical respiratory phase detection without airflow measurement

2000 ◽  
Vol 38 (2) ◽  
pp. 198-203 ◽  
Author(s):  
Z. K. Moussavi ◽  
M. T. Leopando ◽  
H. Pasterkamp ◽  
G. Rempel
Keyword(s):  
Phase Detection ◽  
Respiratory Phase

Evaluation of estimates of alveolar gas exchange by using a tidally ventilated nonhomogenous lung model

1997 ◽  
Vol 82 (6) ◽  
pp. 1963-1971 ◽  
Author(s):  
Thierry Busso ◽  
Peter A. Robbins
Keyword(s):  
Gas Exchange ◽  
Lung Model ◽  
Gas Composition ◽  
Breathing Patterns ◽  
Alveolar Volume ◽  
Gas Concentration ◽  
Pulmonary Capillaries ◽  
Partial Pressures ◽  
End Tidal ◽  
Alveolar Gas Exchange

Busso, Thierry, and Peter A. Robbins. Evaluation of estimates of alveolar gas exchange by using a tidally ventilated nonhomogenous lung model. J. Appl. Physiol. 82(6): 1963–1971, 1997.—The purpose of this study was to evaluate algorithms for estimating O2 and CO2 transfer at the pulmonary capillaries by use of a nine-compartment tidally ventilated lung model that incorporated inhomogeneities in ventilation-to-volume and ventilation-to-perfusion ratios. Breath-to-breath O2 and CO2 exchange at the capillary level and at the mouth were simulated by using realistic cyclical breathing patterns to drive the model, derived from 40-min recordings in six resting subjects. The SD of the breath-by-breath gas exchange at the mouth around the value at the pulmonary capillaries was 59.7 ± 25.5% for O2 and 22.3 ± 10.4% for CO2. Algorithms including corrections for changes in alveolar volume and for changes in alveolar gas composition improved the estimates of pulmonary exchange, reducing the SD to 20.8 ± 10.4% for O2 and 15.2 ± 5.8% for CO2. The remaining imprecision of the estimates arose almost entirely from using end-tidal measurements to estimate the breath-to-breath changes in end-expiratory alveolar gas concentration. The results led us to suggest an alternative method that does not use changes in end-tidal partial pressures as explicit estimates of the changes in alveolar gas concentration. The proposed method yielded significant improvements in estimation for the model data of this study.

Evolution of the Structure and Mechanical Strength of a Coal Particle During Combustion in the Atmosphere of Air and the Mixture of Oxygen and Carbon Dioxide / Ewolucja Struktury Oraz Wytrzymałości Mechanicznej Ziarna Węgla Podczas Spalania W Atmosferze Powietrza Oraz Mieszaninie Tlenu I Dwutlenku Węgla

2013 ◽  
Vol 58 (3) ◽  
pp. 673-690
Author(s):  
Piotr Pełka ◽  
Grzegorz Golański ◽  
Paweł Wieczorek
Keyword(s):  
Carbon Dioxide ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Sudden Change ◽  
Combustion Process ◽  
Ambient Air ◽  
Hard Coal ◽  
Atomic Force ◽  
Coal Particles ◽  
The Moment

Abstract The research was conducted on the basis of four different types of hard coal and one type of brown coal. There are typical coals commonly used as fuel in Polish CFB boilers. The combustion process was conducted at a temperature of 850°C and the atmosphere of ambient air as well as in the mixture of oxygen and carbon dioxide in different proportions. The research was carried out using specially prepared cubical coal particles with measurements of 15×15mm and also 10×10 mm. The change of the mechanical properties was analyzed based on three parameters, i.e. compression strength, Vickers hardness and fracture toughness. The analysis was supplemented by microscopic images of the surface of the particles using an atomic force microscope. The results obtained clearly indicated the mechanical changes of the coal during its combustion, particularly at the moment of ignition of the char. Moreover, the results correlate very well with the processes of coal comminution that have been described by other authors (Basu, 1999; Chirone et al., 1991) during combustion in the circulating fluidized bed and also explain the sudden change of susceptibility to erosion in the conditions with and without combustion. The measured values can be used as strength parameters in the modelling of the mass loss of coal particles in conditions of circulating fluidized bed combustor that are hard to describe.

scholarly journals Automatic respiratory phase detection for functional electrical stimulation synchronization

2018 ◽  
Vol 34 (3) ◽  
pp. 246-253
Author(s):  
Taisa Daiana da Costa ◽  
Guilherme Nunes Nogueira-Neto ◽  
Percy Nohama
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Phase Detection ◽  
Respiratory Phase

Analysis of Respiratory Sinus Arrhythmia with Respect to Respiratory Phase

2000 ◽  
Vol 39 (02) ◽  
pp. 153-156 ◽  
Author(s):  
K. Kotani ◽  
I. Hidaka ◽  
Y. Yamamoto ◽  
S. Ozono
Keyword(s):  
Respiratory Sinus Arrhythmia ◽  
Spontaneous Breathing ◽  
Breath Holding ◽  
Breathing Patterns ◽  
Sinus Arrhythmia ◽  
Paced Breathing ◽  
Phase Domain ◽  
Volume Curve ◽  
Respiratory Phase ◽  
Respiratory Modulation

Abstract:We evaluated the respiratory modulation of heart rate, i.e., respiratory sinus arrhythmia (RSA), with respect to respiratory phase derived from an analytic signal from the lung volume curve, during spontaneous breathing and paced breathing with different patterns. The magnitudes and waveforms of RSA in the phase domain were similar regardless of breathing pattern, even including spontaneous breathing. An examination of the occurrence of heart beats with respect to the respiratory phase revealed that synchronized patterns recently reported in the literature (Nature 392: 239, 1998) were observed during paced breathing with breath holding periods whereby the respiratory phase advanced more slowly. It was concluded that the phase domain approach might be useful in extracting RSA during spontaneous breathing and for elucidating detailed mechanisms for RSA. However, the use of this technique for studies investigating cardio-respiratory coupling should be approached cautiously, as the results may be influenced by breathing patterns.

Trade-off between ammonia exposure and thermal comfort in pigs and the influence of social contact

1999 ◽  
Vol 68 (3) ◽  
pp. 387-398 ◽  
Author(s):  
J. B. Jones ◽  
A. J. F. Webster ◽  
C. M. Wathes
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Choice Experiment ◽  
Social Contact ◽  
Ambient Air ◽  
Ammonia Gas ◽  
Trade Off ◽  
Gas Concentration ◽  
Positional Bias ◽  
Radiant Heater

AbstractThe trade-off made by pigs between exposure to a concentration of ammonia gas recorded in commercial piggeries and thermal comfort was observed in two chronic choice tests. In the first experiment, eight pigs which were paired and eight pigs which were held as singles, were forced to choose between compartments of a preference chamber that were polluted with an ammonia gas concentration of 40 p.p.m. and heated with a 750 W radiant heater or compartments that were unpolluted and unheated, for 8 days. The location of the choice options was switched after 4 days to eliminate positional bias. Air temperature ranged from 0·5 °C to 15·0 °C. In the second experiment, eight pigs held as pairs, were free to choose between compartments that were polluted with an ammonia gas concentration of 40 p.p.m. and heated with a 750 W radiant heater, polluted and unheated, unpolluted and heated and unpolluted and unheated, for 14 days. The location of the choice options was switched after 7 days to eliminate positional bias. Air temperature ranged from 4·0 °C to 24·0 °C. All compartments contained food and water ad libitum; wood shavings were used as bedding material. In both experiments, the location of all pigs was scan sampled every 15 min and their behaviour at this time was recorded instantaneously. Location and behaviour were compared against air temperature. In the first, forced choice experiment, the pigs preferred the heated-polluted compartments when air temperature was less than the estimated lower critical temperature (LCT) (P< 0·001). As air temperature approached the estimated LCT, the pigs occupied the unheated-unpolluted compartments more often. Overall each visit made to the heated-polluted compartments lasted significantly longer at 265 min (paired), 208 min (single) than visits to the unheated-unpolluted compartments at 29 min (paired), 31 min (single) (P< 0·001). Although they could have huddled to conserve heat, the paired pigs spent less time, overall, in the unheated-unpolluted compartments (P< 0·001). When air temperatures were lower than the estimated LCT, the pigs huddled together but as air temperature increased, the pigs spent more time resting apart (P< 0·001) in the heated-polluted compartments. It is suggested that the paired pigs were motivated to remain in the heated-polluted compartments for companionship rather than thermal comfort. In the second, free choice experiment, the pigs preferred to remain in the unpolluted compartments, adjusting their occupancy of the heated and unheated compartments as ambient air temperature decreased or increased above the estimated LCT (P< 0·001). The pigs made fewer visits to the polluted compartments and each visit was shorter, at 44 min (P< 0·001). Visits to the unpolluted compartments lasted for 291 min. It is suggested that the delayed aversion shown to ammonia in both experiments was due to a progressive sense of malaise. However, both experiments indicated that this delayed ammonia aversion was weaker than preference for thermal comfort.

Effect of body size on breathing pattern and fine-particle deposition in children

2004 ◽  
Vol 97 (3) ◽  
pp. 821-826 ◽  
Author(s):  
William D. Bennett ◽  
Kirby L. Zeman
Keyword(s):  
Fine Particle ◽  
Particle Deposition ◽  
Breathing Pattern ◽  
Fine Particles ◽  
Minute Ventilation ◽  
Ambient Air ◽  
Healthy Children ◽  
Overweight Children ◽  
Breathing Patterns ◽  
Increased Risk

Interchild variability in breathing patterns may contribute to variability in fine particle lung deposition and morbidity in children associated with those particles. Fractional deposition (DF) of fine particles (2-μm monodisperse, carnauba wax particles) was measured in healthy children, age 6–13 yr ( n = 36), while they followed a resting breathing pattern previously determined by respiratory inductance plethysmography. Interchild variation in DF, measured by photometry at the mouth, was most strongly predicted by their tidal volume (Vt) ( r =0.79, P < 0.001). Multiple regression analysis further showed that, for any given height and age, Vt increased with increasing body mass index (BMI) ( P < 0.001). The overweight children (≥95th percentile BMI) ( n = 8) had twice the DF of those in the lowest BMI quartile (<25th percentile) ( n = 9; 0.28 ± 0.13 vs. 0.15 ± 0.06, respectively; P < 0.02). In the same groups, resting minute ventilation was also significantly higher in the overweight children (8.5 ± 2.2 vs. 5.9 ± 1.1 l/min; P < 0.01). Consequently, the rate of deposition (i.e., particles depositing/time) in the overweight children was 2.8 times that of the leanest children ( P < 0.02). Among all children, the rate of deposition was significantly correlated with BMI ( r = 0.46, P = 0.004). These results suggest that increased weight in children may be associated with increased risk from inhalation of pollutant particles in ambient air.

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