Effect of timing of FICO2 changes on ventilatory period in domestic fowl

These experiments were conducted to see if the pacing phenomenon found by Kunz and Miller (Respir. Physiol., 22: 167--177, 1974) in the open-loop, unidirectionally ventilated chicken is important in normally breathing birds. In this study, chickens breathed spontaneously through a tracheostomy from a gas source in which the fraction of CO2 (FICO2) could be rapidly changed. A feedback algorithm kept the FICO2 at 0.05 except for a constant duration pulse (approx 0.6 s) of low FICO2 given tau seconds after the beginning of each inspiration. In all birds tested an increase in tau resulted in a proportional increase of both inspiratory period (TI), expiratory period (TE), and the total period (Ttot). Increases in TI were from 0.5 to 1.0 times the increase in tau. Dynamic expeiments showed TI usually changed on the next breath after a step change in tau, and sinusoidal modulation of tau caused concurrent sinusoidal changes in TI, TE, and Ttot. These findings indicate that the phenomenon that produced pacing in the unidirectionally ventilated birds is important to the ventilatory pattern of normal breathing.

Download Full-text

A Dual-Fuzzy Pressure Compensation Based Symmetric Control Scheme of Single-Rod Electro-Hydraulic Actuator

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.816-817.379 ◽

2013 ◽

Vol 816-817 ◽

pp. 379-384

Author(s):

Li Peng Wang ◽

Jun Zheng Wang ◽

Yu Dong He ◽

Jiang Bo Zhao

Keyword(s):

Fast Response ◽

Open Loop ◽

Hydraulic Actuator ◽

Fuzzy Pid Controller ◽

Control Precision ◽

Compact Size ◽

Control Scheme ◽

Pressure Feedback ◽

Pressure Compensation ◽

Feedback Algorithm

In hydraulic robots, single-rod electro-hydraulic actuator is widely employed for fast response, small size-to-power ratio, large output force and compact size. The differences of open loop gains and other parameters make the dynamic characteristics of two moving directions asymmetric in symmetric valve controlled asymmetric cylinder system. To ensure robots moving smoothly and improve control precision, a novel pressure compensation based symmetric control scheme is proposed. Pressure feedback algorithm is mathematically proved feasible. Therefore, a displacement and pressure signals fused fuzzy PID controller is designed. Simulation results verify the feasibility and validity for compensating the asymmetric problems.

Download Full-text

A Digital Compensator Design for Electrohydraulic Single-Rod Cylinder Position Control Systems

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2896157 ◽

1990 ◽

Vol 112 (3) ◽

pp. 403-409 ◽

Cited By ~ 7

Author(s):

J. Watton

Keyword(s):

Control Systems ◽

Closed Loop ◽

Position Control ◽

Open Loop ◽

Closed Loop System ◽

Forward Algorithm ◽

Loop Transfer Function ◽

Compensator Design ◽

Feedback Algorithm ◽

Position Control System

A digital compensator using a forward algorithm, F(z−1), and a feedback algorithm, H(z−1), is developed for an electrohydraulic position control system incorporating an underlapped servovalve and a single-rod cylinder. The main problems encountered with designing such a closed-loop system are discussed, and it is shown how the filter coefficients may be easily determined for a particular class of open-loop transfer function. An excellent comparison between theory and experiment is obtained and it is deduced that one coefficient only need be changed in the forward algorithm for such gain-change dominant systems.

Download Full-text

Room C, 10/16/2000 9: 00 AM - 11: 00 AM (PS) Titration of Hypnotic Agents Using a BIS-Guided Open-Loop Feedback Algorithm For TIVA

Anesthesiology ◽

10.1097/00000542-200009001-00305 ◽

2000 ◽

Vol 93 (3A) ◽

pp. A-305

Author(s):

Donald Mathews ◽

Sanjeev Kumar ◽

Alexander Matveevskii ◽

Monica Klewicka ◽

George Neuman

Keyword(s):

Open Loop ◽

Loop Feedback ◽

Feedback Algorithm

Download Full-text

Trigger Asynchronies Induced by the Introduction of External Gas Into the Non-Invasive Mechanical Ventilation Circuit: A Bench-to-Bedside Study

10.21203/rs.3.rs-637984/v1 ◽

2021 ◽

Author(s):

Cristina Lalmolda ◽

Pablo Flórez ◽

Carles Grimau ◽

Roberto Larrosa ◽

Marta Corral ◽

...

Keyword(s):

Invasive Mechanical Ventilation ◽

Invasive Ventilation ◽

Trigger System ◽

Non Invasive ◽

Gas Source ◽

Ventilatory Pattern ◽

Bench Study ◽

Non Invasive Ventilation ◽

Level Of Effort ◽

Bench Model

Abstract Background and objective: Treatments that require the introduction of external gas into the non-invasive ventilation (NIV) circuit, such as aerosol and oxygen therapy, may influence the performance of the ventilator trigger system. The aim of the study was to determine the presence and type of asynchronies induced by external gas in the NIV circuit in a bench model and in a group of patients undergoing chronic NIV.Methods: Bench study: Four ventilators (one with two different trigger design types) and three gas sources (continuous flow at 4 and 9 l/min and pulsatile flow at 9 l/min) were selected in an active simulator model. The sensitivity of the trigger, the gas introduction position, the ventilatory pattern and the level of effort were also modified.Clinical study: The same ventilators and gas conditions were used in patients undergoing chronic NIV.Results: Bench: The introduction of external gas caused asynchronies in 35.9% of cases (autotriggering 73%, ineffective effort 27%). Significant differences (p<0.01) were detected according to the ventilator model and the gas source.Clinical study: In seven patients, the introduction of external gas induced asynchrony in 20.4% of situations (77% autotriggering). As in the bench study, there were differences in the occurrence of asynchronies depending on the ventilator model and gas source used.Conclusion: The introduction of external gas produces alterations in the ventilator trigger. These alterations are variable, and depend on the ventilator design and gas source. This phenomenon makes it advisable to monitor the patient at the start of treatment.

Download Full-text

A bench-to-bedside study about trigger asynchronies induced by the introduction of external gas into the non-invasive mechanical ventilation circuit

Scientific Reports ◽

10.1038/s41598-021-03291-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Cristina Lalmolda ◽

Pablo Flórez ◽

Carles Grimau ◽

Roberto Larrosa ◽

Marta Corral ◽

...

Keyword(s):

Invasive Mechanical Ventilation ◽

Invasive Ventilation ◽

Trigger System ◽

Non Invasive ◽

Gas Source ◽

Ventilatory Pattern ◽

Bench Study ◽

Non Invasive Ventilation ◽

Level Of Effort ◽

Bench Model

AbstractTreatments that require the introduction of external gas into the non-invasive ventilation (NIV) circuit, such as aerosol and oxygen therapy, may influence the performance of the ventilator trigger system. The aim of the study was to determine the presence and type of asynchronies induced by external gas in the NIV circuit in a bench model and in a group of patients undergoing chronic NIV. Bench study: Four ventilators (one with two different trigger design types) and three gas sources (continuous flow at 4 and 9 l/min and pulsatile flow at 9 l/min) were selected in an active simulator model. The sensitivity of the trigger, the gas introduction position, the ventilatory pattern and the level of effort were also modified. The same ventilators and gas conditions were used in patients undergoing chronic NIV. Bench: the introduction of external gas caused asynchronies in 35.9% of cases (autotriggering 73%, ineffective effort 27%). Significant differences (p < 0.01) were detected according to the ventilator model and the gas source. In seven patients, the introduction of external gas induced asynchrony in 20.4% of situations (77% autotriggering). As in the bench study, there were differences in the occurrence of asynchronies depending on the ventilator model and gas source used. The introduction of external gas produces alterations in the ventilator trigger. These alterations are variable, and depend on the ventilator design and gas source. This phenomenon makes it advisable to monitor the patient at the start of treatment.

Download Full-text

Further Studies on the Ultrastructure of Harderian Gland in Adult Rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051451 ◽

1974 ◽

Vol 32 ◽

pp. 288-289

Author(s):

Alfredo Feria-Velasco ◽

Guadalupe Tapia-Arizmendi

Keyword(s):

Fine Structure ◽

Domestic Fowl ◽

Animal Species ◽

Acinar Cells ◽

Harderian Gland ◽

Myoepithelial Cells ◽

The Other ◽

Albino Rats ◽

Adult Rats ◽

Cell Components

The fine structure of the Harderian gland has been described in some animal species (hamster, rabbit, mouse, domestic fowl and albino rats). There are only two reports in the literature dealing on the ultrastructure of rat Harderian gland in adult animals. In one of them the author describes the myoepithelial cells in methacrylate-embbeded tissue, and the other deals with the maturation of the acinar cells and the formation of the secretory droplets. The aim of the present work is to analize the relationships among the acinar cell components and to describe the two types of cells located at the perifery of the acini.

Download Full-text

CBED study of low-temperature InP grown by gas source MBE

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014988x ◽

1993 ◽

Vol 51 ◽

pp. 810-811

Author(s):

R. Rajesh ◽

M.J. Kim ◽

J.S. Bow ◽

R.W. Carpenter ◽

G.N. Maracas

Keyword(s):

Low Temperature ◽

Second Phase ◽

Material System ◽

Ion Milling ◽

Electrical Measurements ◽

Gas Source ◽

Structural And Electrical Properties ◽

The One ◽

Lt Inp ◽

Gas Source Mbe

In our previous work on MBE grown low temperature (LT) InP, attempts had been made to understand the relationships between the structural and electrical properties of this material system. Electrical measurements had established an enhancement of the resistivity of the phosphorus-rich LT InP layers with annealing under a P2 flux, which was directly correlated with the presence of second-phase particles. Further investigations, however, have revealed the presence of two fundamentally different types of precipitates. The first type are the surface particles, essentially an artefact of argon ion milling and containing mostly pure indium. The second type and the one more important to the study are the dense precipitates in the bulk of the annealed layers. These are phosphorus-rich and are believed to contribute to the improvement in the resistivity of the material.The observation of metallic indium islands solely in the annealed LT layers warranted further study in order to better understand the exact reasons for their formation.

Download Full-text