Dynamic Properties of a Circuit Breaker with Friction-Based Seismic Dampers

1996 ◽  
Vol 12 (2) ◽  
pp. 297-314 ◽  
Author(s):  
R. Kar ◽  
J. H. Rainer ◽  
A. C. Lefrançois
Keyword(s):  
Design Parameter ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Circuit Breaker ◽  
Ground Acceleration ◽  
Discrete Parameter ◽  
Wide Range ◽  
Sf6 Circuit Breaker ◽  
Energy Dissipated

The design parameter of 1.05 g peak seismic ground acceleration for a 300 kV SF6 circuit breaker necessitated the provision of supplemental friction-based dampers. This paper describes the dampers and the dynamic properties of the circuit breaker as obtained from a series of pull-release tests with increasing force amplitudes. These tests permitted a determination of a wide range of damping ratios and natural frequencies as a function of displacements. A comparison is also presented between the measured and the calculated damping ratios and frequencies, using common engineering approximation of the energy dissipated per cycle for damping, and a discrete parameter and linearized stiffness approach for the calculation of natural frequency. Reasonable comparisons were achieved between the measured and calculated values.

scholarly journals Adsorption-Semiconductor Sensor Based on Nanosized SnO2 for Early Warning of Indoor Fires

2021 ◽  
Author(s):  
Nelli Maksymovych ◽  
Ludmila Oleksenko ◽  
George Fedorenko
Keyword(s):  
Tin Dioxide ◽  
Early Stage ◽  
Dynamic Properties ◽  
Sol Gel ◽  
Average Particle Size ◽  
High Sensitivity ◽  
Average Particle ◽  
Semiconductor Sensor ◽  
Wide Range

The paper is devoted for a solution of indoors fires prevention at early stage by determination of H2 (fire precursor gas) in air using a semiconductor sensor. A material based on Pt-containing nanosized tin dioxide with an average particle size of 10–11 nm obtained via a sol–gel method was created for a gas sensitive layer of the sensor. The developed sensor has high sensitivity to H2 micro concentration, a wide range of its detectable content in air, selectivity of H2 measuring in the presence of СО and СН4, good dynamic properties. The combination of these properties is very important for prevention of inflammations on their early stages before the open fires appearance. Economic benefit of the proposed sensor is due to a lower cost and higher reliability of the fire situation detection.

scholarly journals Determination of Methodology and Research of the Influence of the Trial Run of High-Precision Reducers on the Change of Their Characterizing Properties

2021 ◽  
Vol 11 (9) ◽  
pp. 3859
Author(s):  
Marek Kočiško ◽  
Martin Pollák ◽  
Monika Töröková ◽  
Petr Baron ◽  
Dušan Paulišin ◽  
...  
Keyword(s):  
High Precision ◽  
Dynamic Properties ◽  
Critical Parameters ◽  
Positioning Accuracy ◽  
Subsequent Determination ◽  
Wide Range ◽  
Correct Implementation

This paper describes, in detail, the research of the influence of the trial run of high-precision reducers on the change of their characterizing parameters with the subsequent determination of the methodology for the identification of their critical parameters and positioning accuracy. The research was carried out on a sample of high-precision reducers during a 48 h run-in with the evaluation of changes in their characterizing parameters. The developed methodology unifies the approach to measuring the static and dynamic properties of high-precision reducers to identify their critical parameters and positioning accuracy. The article also points to the need for the correct implementation of the process for the introduction of the bearing reducer into operation after its incorporation into the relevant equipment with emphasis on improving the monitored critical parameters. The running-in of reducers is a little-explored area in terms of its effect on changing the wide range of characterizing properties of high-precision reducers. At the same time, it is complicated by the non-existent uniform methodology for the implementation of their run-in.

scholarly journals Theoretical Determination of Porpoising Instability of High-Speed Planing Boats

1978 ◽  
Vol 22 (01) ◽  
pp. 32-53 ◽  
Author(s):  
Milton Martin
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Natural Frequencies ◽  
Theoretical Method ◽  
Theoretical Determination ◽  
Damping Characteristics ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Good Agreement

A theoretical method is derived for predicting trim angle and speed coefficient at the inception of propoising of prismatic planing hulls. Although equations are derived for the surge, pitch, and heave degrees of freedom, it is seen that the effect of surge is small at ordinary operating trim angles. Comparisons of theoretical predictions with existing experimental data on coupled pitch and heave porpoising show reasonably good agreement for a wide range of speed coefficients, load coefficients, and deadrise angles. The theory may also be used for estimating the natural frequencies and damping characteristics of prismatic hulls in the stable, high-speed planing range.

Hydrodynamically Coupled Vibration of Shell With Liquid and Rod Bundles

2002 ◽  
Author(s):  
Vladimir S. Fedotovsky ◽  
Tatiana N. Vereshchagina ◽  
Aleksandr D. Efanov
Keyword(s):  
Continuous Medium ◽  
Heterogeneous Media ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Rod Bundles ◽  
Rod Bundle ◽  
Resonance Vibrations ◽  
Elastic Systems ◽  
Vibration Performance

The conception of effective vibrodynamic properties of heterogeneous media is presented, enabling one to solve various problems on vibration of elastic systems containing liquid and a large number of identical inclusions. The idea of the conception consists in that the liquid with the inclusions (for example, a rod bundle) being affected by vibration is considered a continuous medium with the special dynamic properties – vibrodensity and vibroviscosity. These properties are dependent both on the properties of liquid and inclusions and on the frequency of vibration impacts. It is these vibrodynamic properties upon which the vibration performance of elastic systems containing heterogeneous media is dependent. General equations of vibrodensity and vibroviscosity are used in studying natural and forced vibrations of shell containing liquid and a bundle of elastic rods. It is established that natural frequencies and amplitudes of shell resonance vibrations depend on rod bundle parameters. The result obtained on vibrodensity was used as well for determination of natural frequencies of free-surfacc liquid vibration in cylindrical vessel enclosing rod bundle. It is demonstrated that the natural frequencies of liquid vibration in vessel with rod bundle are lower than in vessel without rods. Comparison of theory with experimental data is made.

scholarly journals Eigenfrequencies of generally restrained beams

2003 ◽  
Vol 2003 (10) ◽  
pp. 503-516 ◽  
Author(s):  
Ricardo Oscar Grossi ◽  
Carlos Marcelo Albarracín
Keyword(s):  
Natural Frequencies ◽  
Equations Of Motion ◽  
Natural Boundary ◽  
Wide Range ◽  
Exact Determination ◽  
Natural Boundary Conditions ◽  
Elastic Constraints ◽  
Range Of Values ◽  
Intermediate Constraints

We deal with the exact determination of eigenfrequencies of a beam with intermediate elastic constraints and generally restrained ends. It is the purpose of this paper to use the calculus of variations to obtain the equations of motion and the natural boundary conditions, and particularly those at the intermediate constraints. Numerical values for the first five natural frequencies are presented in a tabular form for a wide range of values of the restraint parameters. Several particular cases are presented and some of these cases have been compared with those available in the literature.

Model-based approach to investigate equipment-induced error in pressure-waveform derived hemodynamic measurements

2021 ◽  
Author(s):  
Masoud Farahmand ◽  
Hossein Mirinejad ◽  
Christopher G Scully
Keyword(s):  
Natural Frequencies ◽  
Dynamic Properties ◽  
Pulse Contour ◽  
Pressure Monitoring ◽  
Pressure Monitor ◽  
Pressure Recording ◽  
Model Based ◽  
Equivalence Tests ◽  
Wide Range ◽  
Hemodynamic Measurements

Abstract Objective: Advanced hemodynamic monitoring systems have provided less invasive methods for estimating pressure-derived measurements such as pressure-derived cardiac output (CO) measurements. These devices apply algorithms to arterial pressure waveforms recorded via pressure recording components that transmit the pressure signal to a pressure monitor. While standards have been developed for pressure monitoring equipment, it’s unclear how the equipment-induced error can affect secondary measurements from pressure waveforms. We propose an approach for modelling different components of a pressure monitoring system and use this model-based approach to investigate the effect of different pressure recording configurations on pressure-derived hemodynamic measurements. Approach: The proposed model-based approach is a three step process. 1) modelling the response of pressure recording components using bench tests; 2) verifying the identified models through nonparametric equivalence tests; and 3) assessing the effects of pressure recording components on pressure-derived measurements. To delineate the application of this approach, we performed a series of model-based analyses to quantify the combined effect of a wide range of tubing configurations with various damping ratios and natural frequencies and monitors with different bandwidths on pressure waveforms and CO measurements by six pulse contour algorithms. Results: Model-based results show the error in pressure-derived CO measurements because of tubing configurations with different natural frequencies and damping ratios. Tubing configurations with low natural frequencies (<23 Hz) altered characteristics of pressure waveforms in a way that affected the CO measurement, some by as much as 20%. Significance: Our method can serve as a tool to quantify the performance of pressure recording systems with different dynamic properties. This approach can be applied to investigate the effects of physiologic signal recording configurations on various pressure-derived hemodynamic measurements.

Experimental determination of the dynamic properties of a bridge substructure

1971 ◽  
Vol 61 (6) ◽  
pp. 1529-1548
Author(s):  
R. Shepherd ◽  
A. W. Charleson
Keyword(s):  
Steady State ◽  
Experimental Determination ◽  
Vibration Amplitude ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Vibration Tests ◽  
Bridge Substructures

abstract As part of an investigation of the dynamic properties of bridge substructures, a series of steady-state vibration tests were undertaken on a multispan continuous deck bridge at several stages during construction. In this paper the method of testing is outlined and the measured natural frequencies and derived values of equivalent viscous damping are presented. The results confirm that the bridge does behave in a manner reasonably consistent with the design assumptions. At the small values of vibration amplitude generated, an equivalent viscous damping of the order of 4 per cent of critical was determined for the completed bridge.

Automation of selected brazes' dynamic properties in high-temperatures' measurement process

2013 ◽  
Vol 18 (2-3) ◽  
pp. 33-41
Author(s):  
Dominik Sankowski ◽  
Marcin Bakala ◽  
Rafał Wojciechowski
Keyword(s):  
Surface Tension ◽  
High Temperatures ◽  
Dynamic Properties ◽  
Automatic Measurement ◽  
Measurement Methodology ◽  
Joining Process ◽  
Wetting Force ◽  
Research Grant

Abstract The good quality of several manufactured components frequently depends on solidliquid interactions existing during processing. Nowadays, the research in material engineering focuses also on modern, automatic measurement methods of joining process properties, i.a. wetting force and surface tension, which allows for quantitative determination of above mentioned parameters. In the paper, the brazes’ dynamic properties in high-temperatures’ measurement methodology and the stand for automatic determination of braze’s properties, constructed and implmented within the research grant nr KBN N N519 441 839 - An integrated platform for automatic measurement of wettability and surface tension of solders at high temperatures, are widely described

DINAMIKA POLITIK PERSETUJUAN BERSAMA TENTANG PENETAPAN DESA ADAT DI KABUPATEN ROKAN HULU TAHUN 2014

2017 ◽  
Vol 15 (1) ◽  
pp. 21
Author(s):  
Haryo Suganda ◽  
Raja Muhammad Amin
Keyword(s):  
Regulatory Region ◽  
Field Research ◽  
Analysis Techniques ◽  
Political Dynamics ◽  
Political Interests ◽  
Wide Range ◽  
Information Method ◽  
Qualitative Descriptive ◽  
The Village

This study is motivated the identification of policies issued by the regional Governmentof Rokan Hulu in the form of Regulatory region number 1 by 2015 on the determination of thevillage and Indigenous Village. Political dynamics based on various interests against themanufacture of, and decision-making in the process of formation of the corresponding localregulations determination of Indigenous Villages in the Rokan Hulu is impacted to a verysignificantamount of changes from the initial draft of the number i.e. 21 (twenty one) the villagebecame Customary 89 (eighty-nine) the Indigenous Villages who have passed. Type of thisresearch is a qualitative descriptive data analysis techniques. The research aims to describe theState of the real situation in a systematic and accurate fact analysis unit or related research, aswell as observations of the field based on the data (information). Method of data collectionwas done with interviews, documentation, and observations through fieldwork (field research).The results of the research on the process of discussion of the draft local regulations andmutual agreement about Designation of Indigenous Villages in the Rokan Hulu is, showed thatthe political dynamics that occur due to the presence of various political interests, rejectionorally by Villagers who were judged to have met the requirements of Draft Regulations to beformulated and the area for the set to be Indigenous Villages, and also there is a desire fromsome villages in the yet to Draft local regulations in order to set the Indigenous village , there isa wide range of interests of these aspects influenced the agreement to assign the entire localVillage which is in the Rokan Hulu become Indigenous village, and the village of Transmigrationinto administrative Villages where the initiator of the changes in the number of IndigenousVillages in the Rokan Hulu it is the desire of the local Government of its own.

scholarly journals Modelling of speleothems failure in the Hotton cave (Belgium). Is the failure earthquake induced?

2001 ◽  
Vol 80 (3-4) ◽  
pp. 315-321 ◽  
Author(s):  
J.F. Cadorin ◽  
D. Jongmans ◽  
A. Plumier ◽  
T. Camelbeeck ◽  
S. Delaby ◽  
...  
Keyword(s):  
Natural Frequencies ◽  
Quantitative Information ◽  
Rigid Bodies ◽  
Tensile Failure ◽  
Future Research ◽  
Geometrical Parameters ◽  
Laboratory Measurements ◽  
Ground Acceleration ◽  
Strong Ground

AbstractTo provide quantitative information on the ground acceleration necessary to break speleothems, laboratory measurements on samples of stalagmite have been performed to study their failure in bending. Due to their high natural frequencies, speleothems can be considered as rigid bodies to seismic strong ground motion. Using this simple hypothesis and the determined mechanical properties (a minimum value of 0.4 MPa for the tensile failure stress has been considered), modelling indicates that horizontal acceleration ranging from 0.3 m/s2 to 100 m/s2 (0.03 to 10g) are necessary to break 35 broken speleothems of the Hotton cave for which the geometrical parameters have been determined. Thus, at the present time, a strong discrepancy exists between the peak accelerations observed during earthquakes and most of the calculated values necessary to break speleothems. One of the future research efforts will be to understand the reasons of the defined behaviour. It appears fundamental to perform measurements on in situ speleothems.

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