Microfluidic serial digital to analog pressure converter for arbitrary pressure generation and contamination-free flow control

Feiqiao Yu; Mark A. Horowitz; Stephen R. Quake

doi:10.1039/c3lc41394b

Limited acceleration mechanism for cell loss free flow control in ATM networks

Lecture Notes in Computer Science - Computing and Combinatorics ◽

10.1007/bfb0045117 ◽

1997 ◽

pp. 502-511 ◽

Cited By ~ 1

Author(s):

Hong Liu ◽

Enmin Song ◽

Reza Sotudeh

Keyword(s):

Flow Control ◽

Cell Loss ◽

Free Flow ◽

Atm Networks ◽

Acceleration Mechanism

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Design of a Multifunctional Flow Control Valve for Self-Circulating Hydraulic Cylinders

Journal of Pressure Vessel Technology ◽

10.1115/1.4034877 ◽

2017 ◽

Vol 139 (2) ◽

Author(s):

Amin Moosavian ◽

Michael Rizoiu ◽

Fengfeng (Jeff) Xi

Keyword(s):

Flow Control ◽

Flow Direction ◽

Check Valve ◽

Control Valve ◽

Free Flow ◽

Flow Control Valve ◽

Hydraulic Circuit ◽

Aerospace Application ◽

Directional Flow ◽

Hydraulic Cylinders

A new hydraulic circuit is introduced, packaged as a singular component and referred to as a multifunctional flow control (MFC) valve, for usage in conjunction with self-circulating hydraulic cylinders. Unlike conventional check valves, whose directional flow restrictions are permanent, the restriction on the flow direction in the MFC valve can be changed. In addition to being able to act as a check valve in either direction, this valve can allow free flow or no flow of the fluid when required, that is, a total of four positions. The proposed circuit for the MFC valve can effectively be represented as a two-way four-position valve. Furthermore, the design for the valve is validated through experimentation. Additionally, an aerospace application for this valve is presented and discussed herein.

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For trouble-free flow control, install POWELL VALVES

Chemical & Engineering News ◽

10.1021/cen-v030n011.p1109 ◽

1952 ◽

Vol 30 (11) ◽

pp. 1109

Keyword(s):

Flow Control ◽

Free Flow

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Abstract P040: Muscle Metaboreflex Regulation of Arterial Blood Pressure in Children with Congenital Heart Defects

Circulation ◽

10.1161/circ.133.suppl_1.p040 ◽

2016 ◽

Vol 133 (suppl_1) ◽

Author(s):

Corey R Tomczak ◽

Stephanie Fusnik ◽

Elizabeth Hogeweide ◽

Mark J Haykowsky ◽

Michael K Stickland ◽

...

Keyword(s):

Blood Pressure ◽

Flow Control ◽

Congenital Heart Defects ◽

Congenital Heart ◽

Heart Defects ◽

Free Flow ◽

Post Exercise ◽

Muscle Metaboreflex ◽

Arterial Blood ◽

Significant Difference

Introduction: Metabolically sensitive afferent fibers in skeletal muscle can signal an increase the sympathetic control of arterial blood pressure during exercise. This process, called the muscle metaboreflex, is augmented in adults with cardiovascular disease and contributes to exercise intolerance. The role of the muscle metaboreflex on blood pressure control in children with congenital heart defects (CHD) is not known. Hypothesis: We tested the hypothesis that the mean arterial pressure (MAP) response to the muscle metaboreflex would be augmented in children with CHD compared to healthy controls. Methods: Twenty-six children with CHD (11±2 years; males=14; females=12) and 21 age- and sex-matched controls (11±3 years; males=10; females=11) were studied. CHD diagnoses included Tetralogy of Fallot (n=7), pulmonary or aortic stenosis (n=3), hypoplastic left or right heart syndrome (n=5), Ebstien’s anomaly (n=1), atrial or ventricular septal defect (n=5), transposition of the great arteries (n=2), double inlet left ventricle (n=1), heart transplantation (n=2), tricuspid or pulmonary atresia (n=2), coarctation of the aorta (n=2), and dilated cardiomyopathy (n=1). Testing included a 3 min rest period followed by isometric handgrip exercise at 30% of maximal voluntary contraction for 2 min. Exercise was followed by 3 min of either a free flow control condition or circulatory occlusion to isolate the muscle metaboreflex. Beat-by-beat MAP was recorded using finger plethysmography. Analyses were completed using mixed designs factorial ANOVA with P < 0.05 as the level of significance. Data are mean ± SD. Results: During the free flow control condition, there was no significant difference in resting MAP (75±9 mmHg vs. 78±9 mmHg), exercise MAP (86±14 mmHg vs. 87±12 mmHg), or free flow MAP (72±10 mmHg vs. 78±9 mmHg) between children with CHD vs. controls, respectively ( P > 0.05). MAP significantly increased from rest to exercise and returned to resting levels during the free flow control condition for both groups. For the circulatory occlusion condition, there was no significant difference in resting MAP (73±11 mmHg vs. 74±8 mmHg), exercise MAP (84±15 mmHg vs. 81±11 mmHg), or circulatory occlusion MAP (79±13 mmHg vs. 79±13 mmHg) between children with CHD vs. controls, respectively ( P > 0.05). MAP significantly increased from rest to exercise and MAP remained elevated above resting levels during circulatory occlusion for both children with CHD and controls ( P < 0.001 for all). Conclusions: Post-exercise circulatory occlusion significantly increases MAP in children with CHD and healthy children, with no significant difference in the magnitude of the MAP response between groups. We conclude that children with CHD demonstrate a normal muscle metaboreflex during post-exercise circulatory occlusion.

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