A Method for Suppression of Pressure Pulse in Fluid-Filled Piping—Part II: Experimental Verification

1992 ◽  
Vol 114 (1) ◽  
pp. 66-73
Author(s):  
Y. W. Shin ◽  
E. F. Bielick ◽  
A. H. Wiedermann ◽  
C. E. Ockert
Keyword(s):  
Experimental Verification ◽  
Pressure Pulse ◽  
Practical Importance ◽  
Companion Paper ◽  
Nondestructive Method ◽  
Experimental Setup ◽  
Practical Applications ◽  
Test Models ◽  
Pressure Pulses ◽  
Theoretical Predictions

A simple, nondestructive method to suppress pressure pulses in fluid-filled piping was proposed and theoretically analyzed in the previous companion paper. In this paper, the proposed method is verified experimentally. The results of experiments performed for the range of parameters of practical importance indicated that the attenuation of pressure pulses was sufficiently large for practical applications and in accordance with the theoretical predictions. This paper describes the experimental setup and the test models of the proposed pulse suppression devices and discusses the experimental results. In particular, the measured attenuation factors (transmitted pressure/incident pressure) are presented and compared with the theoretical predictions.

A Method for Suppression of Pressure Pulses in Fluid-Filled Piping—Part I: Theoretical Analysis

1992 ◽  
Vol 114 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Y. W. Shin ◽  
A. H. Wiedermann
Keyword(s):  
Theoretical Analysis ◽  
Pressure Pulse ◽  
Substantial Reduction ◽  
Pulse Height ◽  
Practical Interest ◽  
Nondestructive Method ◽  
Trade Off ◽  
Pressure Pulses ◽  
Fluid Jets ◽  
Pressure Surge

A simple, nondestructive method to suppress pressure pulses in fluid-filled piping is theoretically analyzed, and the result provides the basis needed for design and evaluation of a pressure-pulse suppression device based on the proposed theory. The method is based on forming of fluid jets in the event of a pressure surge, such that the pulse height and the energy of the pulse are reduced. The results for pressure pulses in the range of practical interest show that a substantial reduction in the pulse height can be attained, with accompanying reduction of the pulse remaining in the system. The analysis also reveals that a certain amount of trade-off exists in the design of the suppression device; a certain level of pulse energy remaining in the system must be accepted in order to keep the pulse height below a certain level, and vice versa.

scholarly journals Tunable Adhesion of a Bio-Inspired Micropillar Arrayed Surface Actuated by a Magnetic Field

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Xingji Li ◽  
Zhilong Peng ◽  
Yazheng Yang ◽  
Shaohua Chen
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Rotation Angle ◽  
Adhesion Force ◽  
Practical Applications ◽  
Section Shape ◽  
Theoretical Predictions ◽  
Large Elastic Deformation ◽  
The Difference

Bio-inspired functional surfaces attract many research interests due to the promising applications. In this paper, tunable adhesion of a bio-inspired micropillar arrayed surface actuated by a magnetic field is investigated theoretically in order to disclose the mechanical mechanism of changeable adhesion and the influencing factors. Each polydimethylsiloxane (PDMS) micropillar reinforced by uniformly distributed magnetic particles is assumed to be a cantilever beam. The beam's large elastic deformation is obtained under an externally magnetic field. Specially, the rotation angle of the pillar's end is predicted, which shows an essential effect on the changeable adhesion of the micropillar arrayed surface. The larger the strength of the applied magnetic field, the larger the rotation angle of the pillar's end will be, yielding a decreasing adhesion force of the micropillar arrayed surface. The difference of adhesion force tuned by the applied magnetic field can be a few orders of magnitude, which leads to controllable adhesion of such a micropillar arrayed surface. Influences of each pillar's cross section shape, size, intervals between neighboring pillars, and the distribution pattern on the adhesion force are further analyzed. The theoretical predictions are qualitatively well consistent with the experimental measurements. The present theoretical results should be helpful not only for the understanding of mechanical mechanism of tunable adhesion of micropillar arrayed surface under a magnetic field but also for further precise and optimal design of such an adhesion-controllable bio-inspired surface in future practical applications.

Experimental Verification of Open-loop Control for an Underwater Eel-like Robot

2002 ◽  
Vol 21 (10-11) ◽  
pp. 849-859 ◽  
Author(s):  
Kenneth A. Mcisaac ◽  
James P. Ostrowski
Keyword(s):  
Experimental Work ◽  
Experimental Verification ◽  
Vision System ◽  
Open Loop ◽  
Open Loop Control ◽  
Loop Control ◽  
Position Sensing ◽  
Theoretical Predictions ◽  
Approximate Expressions ◽  
Good Agreement

In this paper, we describe experimental work using an underwater, biomimetic, eel-like robot to verify a simplified dynamic model and open-loop control routines. We compare experimental results to previous analytically derived, but approximate expressions for proposed gaits for forward/backward swimming, circular swimming, sideways swimming and turning in place. We have developed a five-link, underwater eel-like robot, focusing on modularity, reliability and rapid prototyping, to verify our theoretical predictions. Results from open-loop experiments performed with this robot in an aquatic environment using an off-line vision system for position sensing show good agreement with theory.

scholarly journals A curved multi-component aerosol hygroscopicity model framework: 1 – Inorganics

2004 ◽  
Vol 4 (6) ◽  
pp. 8627-8676 ◽  
Author(s):  
D. O. Topping ◽  
G. B. McFiggans ◽  
H. Coe
Keyword(s):  
Surface Tension ◽  
Companion Paper ◽  
Dry Density ◽  
Model Framework ◽  
Aerosol Model ◽  
Modelling Framework ◽  
Systematic Uncertainties ◽  
Model Aerosol ◽  
Theoretical Predictions ◽  
Models Comparison

Abstract. A thermodynamic modelling framework to predict the equilibrium behaviour of mixed inorganic salt aerosols is developed, and then coupled with a technique for finding a solution to the Köhler equation in order to create a diameter dependent hygroscopic aerosol model (Aerosol Diameter Dependent Equilibrium Model – ADDEM). The model described here provides a robust and accurate inorganic basis using a mole fraction based activity coefficient model and adjusted energies of formation for treating solid precipitation. The model framework can accommodate organic components, though this added complexity is considered in a companion paper, whereas this paper describes the development of the modelling architecture to be used and predictions of an inorganic model alone. The modelling framework has been developed to flexibly use a combination of mixing rules and other potentially more accurate techniques where available to calculate the water content. Comparisons with other state-of-the-art general equilibrium models and experimental data are presented and show excellent agreement. The Kelvin effect can be considered in this scheme using a variety of surface tension models. Comparison of predicted diameter dependent phenomena, such as the increased relative humidity for onset of deliquescence with decreasing diameter, with another diameter dependent model is very good despite the different approach used. The model is subject to various sensitivities. For the inorganic systems studied here, the model is sensitive to choice of surface tension scheme used, which decreases for larger aerosol. Large sensitivities are found for the value of dry density used. It is thus likely that the history of the aerosol studied in a hygroscopic tandem differential mobility analyser (HTDMA), specifically the nature of the drying process that will influence the final crystalline form, will create systematic uncertainties upon comparisons with theoretical predictions. However, the magnitudes of all of the above sensitivities are potentially less than those introduced when using a semi ideal growth factor analogue for certain conditions.

EXPERIMENTAL VERIFICATION OF PYRAGAS’S CHAOS CONTROL METHOD APPLIED TO CHUA’S CIRCUIT

1994 ◽  
Vol 04 (06) ◽  
pp. 1703-1706 ◽  
Author(s):  
P. CELKA
Keyword(s):  
Periodic Orbits ◽  
Experimental Verification ◽  
Chaos Control ◽  
Control Method ◽  
Experimental Results ◽  
Experimental Setup ◽  
Chua’S Circuit ◽  
Unstable Periodic Orbits ◽  
Chua's Circuit

We have built an experimental setup to apply Pyragas’s [1992, 1993] control method in order to stabilize unstable periodic orbits (UPO) in Chua’s circuit. We have been able to control low period UPO embedded in the double scroll attractor. However, experimental results show that the control method is useful under some restrictions we will discuss.

Morphogenesis of the head and face: discussion report

Development ◽  
1988 ◽  
Vol 103 (Supplement) ◽  
pp. 61-62
Author(s):  
S. E. Wedden
Keyword(s):  
Practical Importance ◽  
Craniofacial Development ◽  
Model Systems ◽  
Cell Populations ◽  
Robert Greene ◽  
Test Models ◽  
Models Of Development ◽  
Molecular Aspects ◽  
Evolutionary Aspects

The discussion following the session on evolution and morphogenesis of the head and face concentrated upon two major issues: (1) How can one test models of development, particularly at biochemical and molecular levels? (2) Are the cell populations of the early facial primordia heterogeneous and when might this heterogeneity arise? The Chairman, J. Z. Young (London), had suggested in his introductory remarks that research into craniofacial development was at last becoming more specialized, having previously dealt with principles and model systems rather than with issues of practical importance. The ensuing lectures clearly demonstrated the direction and advances in current research, both in evolutionary aspects and at the level of morphogenesis. Robert Greene (Philadelphia) opened the general discussion. He emphasized the need to examine biochemical and molecular aspects of craniofacial development. In his view, the conceptual chasm between the gene and metazoan embryogenesis was wide and deep and had remained so in recent years.

Development of an experimental setup for intraoperative angiography system

2021 ◽  
Author(s):  
I.A. Kudashov ◽  
N.V. Kalmykov ◽  
A.R. Alexandrov ◽  
P.G. Ryazantsev ◽  
S.I. Shchukin ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Intraoperative Imaging ◽  
Objective Assessment ◽  
Locally Advanced ◽  
Practical Importance ◽  
Clinical Problem ◽  
The Body ◽  
Experimental Setup ◽  
Intraoperative Angiography ◽  
Vessel Imaging

The treatment of locally advanced tumors of the head and neck presents serious difficulties due to the difficulty of localizing growths, namely the proximity to vital organs and systems of the body (brain, large blood vessels) and the small size of the areas of intervention limits the choice of treatment methods. So, the development of helper methods and hardware of intraoperative visualization of blood vessels is relevant. So, the development of auxiliary methods and hardware means of intraoperative blood vessel imaging for objective assessment of adequacy of blood supply and differentiated recognition of anatomical structures is especially relevant in biomedical optics. The aim of the work is to create an experimental setup for the development, testing and modification of the algorithms for improving the quality of the image of blood vessels against the background of surrounding tissues by optical method. The article is devoted to technological and program features of developing and creating an experimental setup for intraoperative imaging. Clinical problem of the necessity of vessel imaging has been established. Current state of intraoperative vessel imaging has been analyzed. Structure of the setup has been determined. The requirements for parts of the setup have been formulated. Usage of the chlorophyll as a new liquid for blood substitution has been experimentally justified. A MATLAB-based model for quality evaluation of functions of the setup has been developed. The experimental results obtained in the article are of great practical importance for the development of a biotechnological system for intraoperative vessel imaging.

Prediction and Measurement of Payload Swing From Off-Centered Crane Lifts

2015 ◽  
Author(s):  
Kelvin Peng ◽  
William Singhose
Keyword(s):  
Experimental Verification ◽  
Dynamic Models ◽  
Horizontal Motion ◽  
Surrounding Environment ◽  
Theoretical Predictions ◽  
Human Operators ◽  
Lift Off

When crane payloads are lifted off the ground, the payload may unexpectedly swing sideways. This occurs when the hoist cables are at an angle relative to vertical and the payload is not directly beneath the hoist. Because the hoist point is far above the payload, it is difficult for crane operators to know if the hoist cable is perfectly vertical before they start to lift the payload. Some amount of horizontal motion of the payload will always occur at lift off. If an off-centered lift results in significant horizontal motion, then it creates a hazard for the human operators, the payload, and the surrounding environment. This paper develops dynamic models of off-centered lifts and presents experimental verification of the theoretical predictions. To mitigate the detrimental effects of off-centered lifts, autonomous-centering solutions are proposed.

Midlatency respiratory-related somatosensory activity and perception of oral pressure pulses in normal humans

2001 ◽  
Vol 90 (6) ◽  
pp. 2048-2056 ◽  
Author(s):  
J. Andrew Daubenspeck ◽  
Harold L. Manning ◽  
John C. Baird
Keyword(s):  
Evoked Potentials ◽  
Pressure Pulse ◽  
Applied Pressure ◽  
Normal Subjects ◽  
Magnitude Production ◽  
Global Field Power ◽  
Oral Pressure ◽  
Pressure Pulses ◽  
Standard Pressure ◽  
The Right

A direct relationship exists within subjects between midlatency features (<100 ms poststimulus) of respiratory-related evoked potentials and the perceived magnitude of applied oral pressure pulse stimuli. We evaluated perception in 18 normal subjects using cross-modality matching of applied pressure pulses via grip force and estimated mechanoafferent activity in these subjects by computing the global field power (GFP) from respiratory-related evoked potentials recorded over the right side of the scalp. We compared across subjects 1) the predicted magnitude production for a standard pressure pulse and 2) the slope (β) and 3) the intercept (INT) of the Stevens power law to the summed GFP over 20–100 ms poststimulus. Both the magnitude production for a standard pressure pulse and the β showed an inverse relationship with the summed GFP over 20–100 ms poststimulus, although there was no relationship between INT and the summed GFP. This may partially reflect characteristics of the mechanosensors and surely includes aspects of cognitive judgment, because we found and corrected for a high correlation between, respectively, β (and INT) for pressure pulses and β (and INT) for estimation of line lengths, a nonrespiratory modality. The relatively shallow, even inverse GFP-to-perception relationship suggests that, despite marked differences in the magnitude of afferent traffic, normal subjects seem to perceive things similarly.

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