Control of arrhythmic breathing in aerial breathers

1988 ◽  
Vol 66 (1) ◽  
pp. 99-108 ◽  
Author(s):  
William K. Milsom
Keyword(s):  
Control System ◽  
Adaptive Strategy ◽  
Energetic Cost ◽  
Metabolic Demand ◽  
Breathing Patterns ◽  
Air Breathing ◽  
Common Control ◽  
Partial Pressures ◽  
Separate Control ◽  
Peripheral Receptor

Arrhythmic breathing patterns of two basic types occur among the air-breathing vertebrates. These patterns, which appear to be dependent more on inputs from peripheral receptor groups than on a central generator, allow significant fluctuations in the partial pressures of O2 and CO2 in lungs, blood, and tissues with accompanying fluctuations of pH in body fluids. The major components of each pattern are the size and timing of each breath, the length of each episode of breathing, and the length of the pause between episodes of breathing. While each of these components appears to be under separate control, the relative roles of the various receptor groups in the control of each remain unclear. Similarities between data collected from reptiles and hibernating mammals suggest that the arrhythmic breathing patterns seen under physiological conditions in all air-breathing vertebrates may be manifestations of a common control system. The conversion from continuous to arrhythmic breathing seen in mammals entering hibernation further suggests that both continuous and arrhythmic breathing are manifestations of a common control system. The two distinct arrhythmic breathing patterns appear to arise from differences in the supramedullary integration of vagal input in different species. It is suggested that under conditions of reduced metabolic demand, these arrhythmic breathing patterns may represent an adaptive strategy which, in part, serves to reduce the energetic cost of ventilation.

Control of arrhythmic breathing in bimodal breathers: Amphibia

1988 ◽  
Vol 66 (1) ◽  
pp. 6-19 ◽  
Author(s):  
Robert G. Boutilier
Keyword(s):  
Control System ◽  
Gas Exchange ◽  
Lung Ventilation ◽  
Breath Holding ◽  
Breath Hold ◽  
Breathing Patterns ◽  
Gas Exchanges ◽  
Air Breathing ◽  
Activity State ◽  
Breath Pattern

Amphibians employ a system of gas exchange whereby various combinations of the lungs, gills, and skin are used to exploit gas exchanges in both air and water (bimodal breathing). Continuous lung ventilation is rarely observed in these animals. Instead, the dominant breath pattern is arrhythmic in nature and is believed to have evolved in response to a periodic need to supplement aquatic gas exchange. Such a need is largely dependent on the activity state of the animal concerned and its capacity for aquatic gas exchange. The overall control system appears to be one that turns lung ventilation on and off by trigger signals arising from chemo- and mechano-sensitive receptors responding to changing conditions during periods of breath holding and breathing. In amphibians in which the aquatic exchanger is a major avenue for CO2 elimination, [Formula: see text] levels in the lungs and blood do not change substantially in the latter stages of a breath hold. Under these conditions falling levels of oxygen may be the primary stimulus to terminate the breath hold and initiate breathing. There is, however, some interaction between the two gases since elevated CO2 levels affect the sensitivity of the predominantly O2-mediated response. Another major component in determining air-breathing patterns in these animals is their ability to delay the onset of breathing when certain behavioural activities take precedence over the need for additional gas exchange.

Immersion and invariance adaptive finite-time control of air-breathing hypersonic vehicles

2018 ◽  
Vol 233 (7) ◽  
pp. 2626-2641 ◽  
Author(s):  
Chao Han ◽  
Zhen Liu ◽  
Jianqiang Yi
Keyword(s):  
Control System ◽  
Finite Time ◽  
Control Method ◽  
Sliding Mode ◽  
Second Order ◽  
Hypersonic Vehicles ◽  
Terminal Sliding Mode ◽  
Air Breathing ◽  
Immersion And Invariance ◽  
Time Control

In this paper, a novel adaptive finite-time control of air-breathing hypersonic vehicles is proposed. Based on the immersion and invariance theory, an adaptive finite-time control method for general second-order systems is first derived, using nonsingular terminal sliding mode scheme. Then the method is applied to the control system design of a flexible air-breathing vehicle model, whose dynamics can be decoupled into first-order and second-order subsystems by time-scale separation principle. The main features of this hypersonic vehicle control system lie in the design flexibility of the parameter adaptive laws and the rapid convergence to the equilibrium point. Finally, simulations are conducted, which demonstrate that the control system has the features of fast and accurate tracking to command trajectories and strong robustness to parametric and non-parametric uncertainties.

THE EFFECTS OF ALTERED AQUATIC AND AERIAL RESPIRATORY GAS CONCENTRATIONS ON AIR-BREATHING PATTERNS IN A PRIMITIVE FISH (AMIA CALVA)

1993 ◽  
Vol 181 (1) ◽  
pp. 81-94 ◽  
Author(s):  
M. S. Hedrick ◽  
D. R. Jones
Keyword(s):  
Air Flow ◽  
The Body ◽  
Type I ◽  
Type Ii ◽  
Breathing Frequency ◽  
Breathing Patterns ◽  
Flow Measurements ◽  
Air Breathing ◽  
Gas Bladder ◽  
Amia Calva

The mechanisms and physiological control of air-breathing were investigated in an extant halecomorph fish, the bowfin (Amia calva). Air flow during aerial ventilation was recorded by pneumotachography in undisturbed Amia calva at 20–24°C while aquatic and aerial gas concentrations were independently varied. Separation of aquatic and aerial gases was used in an attempt to determine whether Amia calva monitor and respond to changes in the external medium per se or to changes in dissolved gases within the body. Air flow measurements revealed two different types of ventilatory patterns: type I air-breaths were characterized by exhalation followed by inhalation; type II air-breaths, which have not been described previously in Amia calva, consisted of single inhalations with no expiratory phase. Expired volume (Vexp) for type I breaths ranged from 11.6+/−1.1 to 26.7+/− 2.9 ml kg-1 (95 % confidence interval; N=6) under normoxic conditions and was unaffected by changes in aquatic or aerial gases. Gas bladder volume (VB), determined in vitro, was 80 ml kg-1; the percentage of gas exchanged for type I breaths ranged from 14 to 33 % of VB in normoxia. Fish exposed to aquatic and aerial normoxia (PO2=19-21 kPa), or aerial hypercapnia (PCO2=4.9 kPa) in normoxic water, used both breath types with equal frequency. Aquatic or aerial hypoxia (PO2=6-7 kPa) significantly increased air-breathing frequency in four of eight fish and the ventilatory pattern changed to predominantly type I air-breaths (75–92 % of total breaths). When fish were exposed to 100 % O2 in the aerial phase while aquatic normoxia or hypoxia was maintained, air-breathing frequency either increased or did not change. Compared with normoxic controls, however, type II breaths were used almost exclusively (more than 98 % of total breaths). Type I breaths appear to be under feedback control from O2-sensitive chemoreceptors since they were stimulated by aquatic or aerial hypoxia and were nearly abolished by aerial hyperoxia. These results also indicate that Amia calva respond to changes in intravascular PO2; however, externally facing chemoreceptors that stimulate air-breathing in aquatic hypoxia cannot be discounted. Type II air- breaths, which occurred in aerial hyperoxia, despite aquatic hypoxia, appear to be stimulated by reductions of VB, suggesting that type II breaths are controlled by volume-sensitive gas bladder stretch receptors. Type II breaths are likely to have a buoyancy-regulating function.

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.

scholarly journals Sensorless vector control of a permanent magnet synchronous motor

2019 ◽  
Vol 91 ◽  
pp. 01007 ◽  
Author(s):  
Ruslan Zhiligotov ◽  
Vyacheslav Shestakov ◽  
Vladymyr Sosnin ◽  
Evgeniy Popkov
Keyword(s):  
Control System ◽  
Vector Control ◽  
Permanent Magnets ◽  
Permanent Magnet Synchronous Motor ◽  
Synchronous Motor ◽  
Adaptive Observer ◽  
Current Position ◽  
Sensorless Vector Control ◽  
Common Control ◽  
Vector Control System

The most common control system for a synchronous motor with permanent magnets is a vector control system. The construction of such a system has a number of difficulties, one of them is the need to have information about the current position of the rotor. Data on the position of the rotor can be obtained using sensors, or include a supervisor in the control system. The article describes an adaptive observer of the position and speed of the rotor of a synchronous motor with permanent magnets. This observer is used in the system of sensorless vector control of the electric drive. The presented version of the observer of the engine state is realized by creating a model in the Matlab Simulink software package. The results of experimental verification of the presented observer at the stand with the use of an engine with a power of 200 W are shown. The aim of the work is to develop an observer that is stable to changing drive parameters. This is achieved by using a relay unit in the view of the observer, which implements the slip mode.

A reconfigurable structure electronic commutator for a dual BLDC motor EV drive

2012 ◽  
Vol 60 (4) ◽  
pp. 769-778
Author(s):  
T. Biskup ◽  
A. Bodora ◽  
A. Domoracki
Keyword(s):  
Control System ◽  
Electric Vehicle ◽  
Motor Drives ◽  
Bldc Motor ◽  
Motor Speed ◽  
Common Control ◽  
Speed Range ◽  
Constant Power Speed Range ◽  
Reconfigurable Structure ◽  
Electronic Commutator

Abstract An electronic commutator that can drive a PM BLDC motor either in the full bridge or half bridge configuration has been developed. This commutator allows increasing the motor speed over the nominal value, hence the motor is able to operate within a wide constant power speed range. An application of the commutator with a reconfigurable structure for the double drive of a small electric vehicle Elipsa has been presented. The driveline consists of two independent commutators feeding the motors coupled by gears with rear wheels of the vehicle. Both commutators are controlled by a common control system based on a signal microcontroller. The results of road tests indicate new areas of BLCD motor drives application. The fact that the BLCD motor work in the second speed range does not require any changes in the motor construction and at the same time does not significantly deteriorate the drive efficiency is an indisputable advantage of the presented solution

Aerial respiration in the catfish, Corydoras aeneus (Callichthyidae)

1980 ◽  
Vol 58 (11) ◽  
pp. 1984-1991 ◽  
Author(s):  
Donald L. Kramer ◽  
Martha McClure
Keyword(s):  
Dissolved Oxygen ◽  
Air Breathing ◽  
Aerial Respiration ◽  
Posterior Intestine ◽  
Partial Pressures

Corydoras aeneus uses the posterior intestine for aerial respiration. Ventilation takes place in a rapid dash to the surface. Air is inspired during the 0.06–0.07 s that the mouth is exposed; expiration occurs via the anus as the fish begins to dive. Air breathing occurs at all dissolved oxygen partial pressures [Formula: see text] from 0 Torr (1 Torr = 133.322 Pa) to at least 140 Torr, but frequency, ranging from 1–45 breaths∙h−1, is negatively correlated with [Formula: see text]. Corydoras aeneus survive at least 9 days without air breathing under normoxic conditions [Formula: see text] but below 15 Torr, only fish able to reach the surface survive. Air-breathing rates are significantly influenced by variations in depth between 10–120 cm but the pattern of response depends on [Formula: see text] and involves changes in activity.

Air-breathing mechanics in two Amazonian teleosts, Arapaima gigas and Hoplerythrinus unitaeniatus

1978 ◽  
Vol 56 (4) ◽  
pp. 939-945 ◽  
Author(s):  
A. P. Farrell ◽  
D. J. Randall
Keyword(s):  
Gas Pressure ◽  
Breathing Patterns ◽  
Air Breathing ◽  
Arapaima Gigas ◽  
Breathing Mechanics ◽  
Replacement Technique ◽  
Hoplerythrinus Unitaeniatus

The mechanics of air breathing in pirarucu, Arapaima gigas, and jeju, Hoplerythrinus unitaeniatus, were studied by simultaneous monitoring of air bladder gas pressure and buccal pressure. Also the effect of alterations in air bladder gas tensions on air-breathing patterns was examined by a gas replacement technique. Pirarucu surface every 4.2 min to make a single ventilation of the air bladder, whilst jeju usually make two or three ventilations at an air breath every 3.0 min. Pirarucu exhale first, then inhale, but in jeju buccal filling occurred before lung emptying. Inhalation in pirarucu is a result of air bladder aspiration combined with the action of a buccal pump; however, lung filling in jeju is achieved by a buccal pump only. The significance of aspiration breathing in pirarucu is discussed. Both fish respond similarly to alterations in air bladder gas tensions. Hyperoxia prolongs the interval between air breaths and hypercapnia reduces this interval.

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