Root Mean Square Response of Transducer Systems to Spectral Density Inputs

1987 ◽  
Author(s):  
G. A. Articolo
Keyword(s):  
Spectral Density ◽  
Root Mean Square ◽  
Mean Square ◽  
Mean Square Response

scholarly journals Deterministic and Probabilistic Foundation Forces Resulting From an Unbalanced Turbine

1976 ◽  
Author(s):  
L. Boyce ◽  
T. J. Kozik
Keyword(s):  
Root Mean Square ◽  
Center Of Mass ◽  
Random Variable ◽  
Degree Of Freedom ◽  
Mean Square ◽  
Single Degree Of Freedom ◽  
Principal Mode ◽  
Single Degree ◽  
Rotating Machine ◽  
Mean Square Response

This paper considers the problem of the unbalanced rotating turbine as a single degree of freedom system, wherein the principal mode of vibration is a translation in the direction of the machine supports. The distance from the center of mass of the rotating mass to the geometric axis, also known as the effective eccentricity, is modeled as a random variable. The expression for the root mean square response of the rotating machine is derived and related to the statistical analog for the deterministic expression for the foundation force. These results are numerically compared to their equivalent deterministic values.

scholarly journals TESTING, ANALYSIS AND COMPARISON FOR CHARACTERISTICS OF AGRICULTURAL FIELD AND ASPHALT ROAD ROUGHNESS

2020 ◽  
pp. 147-154
Author(s):  
Lijuan Wang ◽  
Jianguo Yan ◽  
Shengshi Xie ◽  
Chunguang Wang
Keyword(s):  
Spectral Density ◽  
Root Mean Square ◽  
Power Spectral Density ◽  
Mean Square ◽  
Agricultural Field ◽  
Power Spectral ◽  
Fitting Method ◽  
Density Fitting ◽  
Asphalt Road ◽  
Surface Profiles

Measuring and analysing the roughness of agricultural field and road have great significance for studying the characteristics of tractor dynamic response. This study was designed to analyse and compare the roughness characteristics of agricultural field and asphalt road profiles. A profiling apparatus was developed to measure field and road surface profiles of parallel tracks. The profile measurements were conducted in a grass field, a corn stubble field, a harvested potato field and on an asphalt road. The root mean square value and two spectrum parameters of surface profiles were calculated and analysed to investigate the roughness characteristics of fields and asphalt road. The results of the study indicate that for the values of the agricultural field and asphalt road surface roughness, waviness and roughness index are both positive associated with the root mean square value. Most of the waviness values of all measured field profiles were less than 2 with the average of 1.8, while the waviness values of all measured asphalt road profiles were greater than 2 with the average of 2.08. The roughness of both field and asphalt road profiles can be distinguished by the power spectral density fitting method. However, it has better performance in characterizing asphalt road profiles than characterizing field profiles with the power spectral density fitting method.

Diaphragm electromyogram root mean square response to hypercapnia and its intersubject and day-to-day variation

2005 ◽  
Vol 98 (1) ◽  
pp. 274-281 ◽  
Author(s):  
Bhajan Singh ◽  
Janine A. Panizza ◽  
Kevin E. Finucane
Keyword(s):  
Root Mean Square ◽  
Functional Residual Capacity ◽  
Minute Ventilation ◽  
Random Order ◽  
Mean Square ◽  
Quiet Breathing ◽  
Diaphragm Position ◽  
Mean Square Response ◽  
Residual Capacity ◽  
End Tidal

Diaphragm activation can be quantified by measuring the root mean square of crural EMG (RMSdi) (Beck J, Sinderby C, Lindstrom L, and Grassino A, J Appl Physiol 85: 1123–1134, 1998). To examine intersubject and day-to-day variation in the RMSdi-Pco2 relationship, end-tidal Pco2, minute ventilation (V̇e), respiratory frequency (fB), and RMSdi were measured in seven healthy subjects on two occasions during steady-state ventilation at seven levels of inspired O2 fraction (FiCO2) from 0 to 0.08 in random order. RMSdi was measured with a multielectrode esophageal catheter and controlled for signal contamination and diaphragm position. RMSdi was normalized for values obtained during quiet breathing at functional residual capacity, at FiCO2 of 0.04, and during an inspiratory capacity maneuver (RMSdi%max) as well as ECG R-wave amplitude at functional residual capacity (RMSdi/ECGR), fB, and thickness of the costal diaphragm measured by ultrasound. RMSdi increased linearly with Pco2 (mean r2 = 0.83 ± 0.10); at the highest FiCO2, RMSdi%max was 40.2 ± 11.6%. Relative to the intersubject variation in the V̇e-Pco2 relationship, intersubject variations in the slopes and intercepts of the RMSdi-Pco2 relationships were 1.7 and 1.8 times, respectively, and RMSdi%max-Pco2 relationships 0.9 and 1.3 times, respectively, and were unrelated to fB and diaphragm thickness. Relative to the day-to-day variation in the V̇e-Pco2 relationship, day-to-day variation in the slopes and intercepts of the RMSdi-Pco2 relationships were 2.8 and 4.4 times, respectively, and RMSdi/ECGR-Pco2 relationships 1.3 and 2.2 times, respectively. It was concluded that the RMSdi-Pco2 relationship measures chemosensitivity and is best compared between subjects via RMSdi%max and on separate occasions in the same subject via RMSdi/ECGR.

scholarly journals Analytical Predictions of the Air Gap Response of Floating Structures

2001 ◽  
Vol 123 (3) ◽  
pp. 112-117 ◽  
Author(s):  
Lance Manuel ◽  
Bert Sweetman ◽  
Steven R. Winterstein
Keyword(s):  
Root Mean Square ◽  
Air Gap ◽  
Second Order ◽  
Mean Square ◽  
Floating Structures ◽  
Field Point ◽  
Extreme Response ◽  
Wave Effects ◽  
Mean Square Response ◽  
Single Field

Two separate studies are presented here that deal with analytical predictions of the air gap for floating structures. 1) To obtain an understanding of the importance of first and second-order incident and diffracted wave effects as well as to determine the influence of the structure’s motions on the instantaneous air gap, statistics of the air gap response are studied under various modeling assumptions. For these detailed studies, a single field point is studied here—one at the geometric center (in plan) of the Troll semi-submersible. 2) A comparison of the air gap at different locations is studied by examining response statistics at different field points for the semi-submersible. These include locations close to columns of the four-columned semi-submersible. Analytical predictions, including first and second-order diffracted wave effects, are compared with wave tank measurements at several locations. In particular, the gross root-mean-square response and the 3-h extreme response are compared.

scholarly journals The Silencing of U.S. Campuses Following the COVID-19 Response: Evaluating Root Mean Square Seismic Amplitudes Using Power Spectral Density Data

2021 ◽  
Author(s):  
David L. Guenaga ◽  
Omar E. Marcillo ◽  
Aaron A. Velasco ◽  
Chengping Chai ◽  
Monica Maceira
Keyword(s):  
Spectral Density ◽  
Root Mean Square ◽  
Power Spectral Density ◽  
Active Regions ◽  
The United States ◽  
School Closure ◽  
Mean Square ◽  
School Closures ◽  
Power Spectral ◽  
Seismic Amplitudes

Abstract In response to the COVID-19 global pandemic, many populated and active regions have become deserted and show significant reductions in their background seismicity, especially campuses across the United States (U.S.). Seismic sensors located in the vicinity of or within U.S. campuses show that anthropogenic seismic noise remains elevated during the ordinary, nonpandemic, academic year, only subduing during periods of recess (e.g., winter break). Here, we use power spectral density (PSD) data computed by the Incorporated Research Institutions for Seismology Data Management Center for quality assessment to calculate root mean square (rms) amplitude and analyze the effects of the COVID-19 school closures. We processed and analyzed PSD data for 46 seismic stations located within 50 m of a U.S. university or college. Results show that 42 campus stations show an overall rms drop following a statewide school closure.

Comparing Random Vibration Inputs: Power Spectral Density (PSD) Versus Root Mean-Square Acceleration (Grms)

2003 ◽  
Author(s):  
Ivan Straznicky
Keyword(s):  
Spectral Density ◽  
Root Mean Square ◽  
Power Spectral Density ◽  
Fatigue Damage ◽  
Random Vibration ◽  
Mean Square ◽  
Vibration Effect ◽  
Operating Environments ◽  
Power Spectral ◽  
Magnitude Difference

Many defense programs have vibration requirements for electronics which are often specified as random vibration input. Often, this input is based on measurements taken at the locations of interest for the spectrum of vehicle operating environments. The resulting specification is typically several power spectral density, or PSD, curves with associated durations. The root mean square acceleration, or Grms, can be readily calculated for each PSD curve. Grms values are sometimes used to compare different PSD curves for severity. However, this can be misleading. The impacts of two different random vibration inputs, with the same Grms value, can be very different. By calculating fatigue damage values for various components on a circuit card assembly subjected to these inputs, it can be shown that equal Grms values do not result in equal damage. In fact, there can be two orders of magnitude difference in component damage values. This means that Grms values are very poor indicators of random vibration effect, and should not be used for comparison purposes.

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