Field trials with the LaCoste and Romberg straight‐line gravimeter

Geophysics ◽  
1983 ◽  
Vol 48 (5) ◽  
pp. 611-617 ◽  
Author(s):  
H. D. Valliant
Keyword(s):  
Correlation Analysis ◽  
Field Tests ◽  
Cross Coupling ◽  
Field Trials ◽  
Coupling Effects ◽  
Straight Line ◽  
Corrected Data ◽  
Correlation Techniques ◽  
The Cross

During field tests in 1980, the prototype of the LaCoste and Romberg straight‐line gravimeter (ser. no. SL-1) generally produced gravity values intermediate between those of two comparison “S” meters (ser. nos. S-56 and S-41). Correlation analysis shows that the data from SL-1 with no cross‐coupling correction are 15 percent smoother even in rough weather than the corrected data from either S meter. When corrections to the cross‐coupling effects are applied through postcruise correlation techniques, the curvature (degree of smoothness) of the respective data agrees to within 2 percent for each meter. These results verify that cross‐coupling errors have been virtually eliminated in the new gravimeter.

LaCoste and Romberg straight‐line gravity meter

Geophysics ◽  
1983 ◽  
Vol 48 (5) ◽  
pp. 606-610 ◽  
Author(s):  
Lucien LaCoste
Keyword(s):  
Cross Coupling ◽  
Coupling Effects ◽  
New Model ◽  
Silicone Fluid ◽  
Air Damping ◽  
Straight Line ◽  
New Instrument ◽  
Spring Suspension ◽  
Fluid Damping ◽  
Rough Handling

The LaCoste and Romberg straight‐line gravity meter uses a new suspension in which the movable element moves vertically in a straight line rather than in an arc of a circle (LaCoste, 1973a). It was designed primarily for shipboard operation to avoid effects from cross coupling between various ship accelerations, thereby making it unnecessary to correct for such effects. The straight‐line suspension is a modification of the zero length spring suspension used in all LaCoste and Romberg gravity meters. The new model also uses silicone fluid damping rather than the air damping used in earlier models. Its main advantages over the older models appear to be: it is (1) free of cross‐coupling effects, (2) easier to build and adjust, (3) less subject to slight degradation in performance from rough handling, and (4) less sensitive to ship vibrations. In spite of the above advantages it is doubtful whether the new model will give substantially better accuracy than the previous models, if the previous models are kept in good operating condition by making occasional crosscorrelation analyses (LaCoste, 1973b). Valliant (1983, this issue) describes sea tests of the new instrument.

Theoretical Investigation on Cross-Coupling Effect of Two-Dimensional Compound Pendulum Tiltmeter

2018 ◽  
Vol 07 (02n03) ◽  
pp. 1850007
Author(s):  
Lihua Wu ◽  
Yu Huang
Keyword(s):  
Dynamic Response ◽  
Vibration Isolation ◽  
Coupling Effect ◽  
Low Frequency ◽  
Cross Coupling ◽  
Coupling Factor ◽  
Two Dimensional ◽  
Coupling Coefficients ◽  
Coupling Effects ◽  
The Cross

The active vibration isolation of low-frequency tilt is important for precise scientific measurement. However, the cross-coupling effects in tilt sensitive probes introduce negative effects on the performance of active isolation devices. In this paper, we show the structure and basic principle of compound pendulum (CP)-type tiltmeter, and analyze the dynamic response of the CP to the two-dimensional tilt vibrations. Besides, we deduce theoretically the mathematical model of the capacitive sensing of the displacements of the CP. Finally, we evaluate numerically the cross-coupling effects of a tilt sensitive probe including the cross-couplings of dynamic response and the different capacitance variations in two orthogonal degrees of freedoms. The maximum of the mechanical dynamic coupling factor is less than −60[Formula: see text]dB. The total cross-coupling coefficients including the different capacitance variations of the probe are both less than [Formula: see text]. Therefore, the cross-coupling effects don’t have to be considered for this kind of two-dimensional tilt sensitive probe.

Using Cross-Coupling Effects for Suppression of Contact Severity

2014 ◽  
Vol 614 ◽  
pp. 48-52 ◽  
Author(s):  
Zhi Yong Shang ◽  
Talgar Shaymurat ◽  
Li Jun Xu
Keyword(s):  
Contact Surface ◽  
Cross Coupling ◽  
Stability Domain ◽  
Coupling Effects ◽  
System Parameters ◽  
The Cross ◽  
The Stability ◽  
Rotor Stiffness

In this paper the influence of cross-coupling effects on the rubbing-related dynamics of rotor/stator systems is investigated. The model considered in this paper is a 4-dof rotor/stator system which takes into account the dynamics of the stator and the deformation on the contact surface as well as the cross-coupling effects. The stability of the synchronous full annular rub solution of the model is first analyzed. Then, the cross-coupling effects on the stability of the system at different system parameters are studied. It is found that the cross-coupling effects of the rotor stiffness as well as those of the stator damping and stiffness will benefit the synchronous full annular rubs while the cross-coupling damping of the rotor will reduced the stability domain of the response and lead the system to a response with a heavier rubbing

scholarly journals On the Cross Coupling Effects in Structural Response of Switched Reluctance Motor Drives

2019 ◽  
Vol 34 (2) ◽  
pp. 620-630 ◽  
Author(s):  
Marcio Kimpara ◽  
Shiliang Wang ◽  
Renata Reis ◽  
Joao Pinto ◽  
Mehdi Moallem ◽  
...  
Keyword(s):  
Structural Response ◽  
Cross Coupling ◽  
Switched Reluctance Motor ◽  
Motor Drives ◽  
Coupling Effects ◽  
Switched Reluctance ◽  
Reluctance Motor ◽  
The Cross ◽  
Switched Reluctance Motor Drives

Microdensitometer—computer correlation analysis of ultrastructural periodicity

1978 ◽  
Vol 36 (2) ◽  
pp. 32-33
Author(s):  
D.R. Ensor ◽  
C.G. Jensen ◽  
J.A. Fillery ◽  
R.J.K. Baker
Keyword(s):  
Correlation Analysis ◽  
Background Noise ◽  
Computer Control ◽  
Optical Diffraction ◽  
Screw Thread ◽  
Straight Line ◽  
Computer Storage ◽  
Correlation Process ◽  
Electron Microscope Image ◽  
Fixed Beam

Because periodicity is a major indicator of structural organisation numerous methods have been devised to demonstrate periodicity masked by background “noise” in the electron microscope image (e.g. photographic image reinforcement, Markham et al, 1964; optical diffraction techniques, Horne, 1977; McIntosh,1974). Computer correlation analysis of a densitometer tracing provides another means of minimising "noise". The correlation process uncovers periodic information by cancelling random elements. The technique is easily executed, the results are readily interpreted and the computer removes tedium, lends accuracy and assists in impartiality.A scanning densitometer was adapted to allow computer control of the scan and to give direct computer storage of the data. A photographic transparency of the image to be scanned is mounted on a stage coupled directly to an accurate screw thread driven by a stepping motor. The stage is moved so that the fixed beam of the densitometer (which is directed normal to the transparency) traces a straight line along the structure of interest in the image.

Sign in / Sign up

Export Citation Format

Share Document