Direct and Indirect Vibro-Acoustic Measurements for Road Noise NVH Predictions

2005 ◽  
Author(s):  
Alessandro Zanarini ◽  
Filip De Coninck ◽  
Krzysztof Mendrok ◽  
Paul Sas
Keyword(s):  
Complex Structure ◽  
Indirect Measurement ◽  
Acoustic Measurements ◽  
Road Noise ◽  
Indirect Measurements ◽  
Direct Measurements ◽  
Path Direction ◽  
Vehicle Technologies ◽  
Structure Measurement ◽  
Reverse Path

This paper describes vibro-acoustic direct and indirect measurements for road noise NVH predictions from a complete car. Attention is devoted to the dynamic response of the structure and interior pressure field toward tire patch displacement inputs. The direct measurements exploited the Team Corporation CUBE™ high frequency 6 degree-of-freedom (DOF) shaker recently installed at the KULeuven Vehicle Technologies Laboratory; the input was provided directly at the tire contact patch, while the responses were measured as accelerations and pressures on the structure. In the indirect measurements a low-mid frequency volume velocity source (LMFVVS) was used to acoustically excite the structure in the reverse path direction from the inside of the interior car cavity, while accelerations on the car and forces/torques where acquired by a 6-DOF dynamometer at the tire patch. From both types of excitations Frequency Response Functions (FRF) were calculated in the frequency range [0–500 Hz]. The non-linearity of the full car system was investigated with different direct and indirect measurement tests, in order to assess the feasibility of the reciprocity principle in such a complex structure. Measurement set-ups, results and comparisons are described and discussed in detail.

scholarly journals Studies on the amount and composition of digesta flowing through the duodenum of dairy cows. 2. Sites of net absorption of magnesium and calcium from the alimentary tract.

1973 ◽  
Vol 21 (1) ◽  
pp. 44-55
Author(s):  
A. Kemp ◽  
A. van't Klooster ◽  
P.A.M. Rogers ◽  
J.H. Geurink
Keyword(s):  
Polyethylene Glycol ◽  
Dairy Cows ◽  
Alimentary Tract ◽  
Indirect Measurement ◽  
Indirect Measurements ◽  
Direct Measurements ◽  
Faecal Samples ◽  
Balance Trials

Two cows were fitted with re-entrant duodenal cannulas, and four with T-piece duodenal annulas. Balance trials were carried out, the cows receiving either a winter ration, or freshly-mown herbage. Direct measurements were made of the flow of digesta, and of the amounts of Mg and Ca in both duodenal and faecal samples. Also indirect measurements were made of these parameters, using polyethylene glycol and chromium sesquioxide indicators. Net Ca absorption was restricted to the intestines, and, at high Mg intake, net Mg absorption was also largely intestinal, though too large an error attached to the indirect measurement of Mg absorption rates for reliable conclusions to be drawn. There was considerable secretion of Ca proximal to the duodenum. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Low-cost Indirect Measurement Methods for Self-x Integrated Sensory Electronics for Industry 4.0

2020 ◽  
Vol 87 (s1) ◽  
pp. s79-s84
Author(s):  
Qummar Zaman ◽  
Senan Alraho ◽  
Andreas König
Keyword(s):  
Industry 4.0 ◽  
Degrees Of Freedom ◽  
Performance Metrics ◽  
Low Cost ◽  
Indirect Measurement ◽  
Measurement Methods ◽  
Instrumentation Amplifier ◽  
Performance Parameters ◽  
Current Feedback ◽  
Indirect Measurements

AbstractThe conventional method for testing the performance of reconfigurable sensory electronics of industry 4.0 relies on the direct measurement methods. This approach gives higher accuracy but at the price of extremely high testing cost and does not utilize the new degrees of freedom for measurement methods enabled by industry 4.0. In order to reduce the test cost and use available resources more efficiently, a primary approach, called indirect measurements or alternative testing has been proposed using a non-intrusive sensor. Its basic principle consists in using the indirect measurements, in order to estimate the sensory electronics performance parameters without measuring directly. The non-intrusive property of the proposed method offers better performance of the sensing electronics and virtually applicable to any sensing electronics. Efficiency is evaluated in terms of model accuracy by using six different classical metrics. It uses an indirect current-feedback instrumentation amplifier (InAmp) as a test vehicle to evaluate the performance parameters of the circuit. The device is implemented using CMOS 0.35 μm technology. The achieved maximum value of average expected error metrics is 0.24, and the lowest value of correlation performance metrics is 0.91, which represent an excellent efficiency of InAmp performance predictor.

Association Between Scapular Posture and Two Different Pectoralis Minor Length Tests in Adolescents

2021 ◽  
pp. 1-6
Author(s):  
Leyla Eraslan ◽  
Gulcan Harput ◽  
Damla Deniz ◽  
Taha Yildiz ◽  
Burak Ulusoy ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Direct Measurement ◽  
Crucial Role ◽  
Indirect Measurement ◽  
Rank Test ◽  
Postural Asymmetry ◽  
Limited Knowledge ◽  
Pectoralis Minor ◽  
Direct Measurements ◽  
Length Measurements

Postural asymmetry due to the alterations in scapular posture is typically considered to be associated with injury. Pectoralis minor (PM) has played a crucial role in scapular posture, but limited knowledge exists that shows the possible effect of PM length on static scapular positioning in adolescents. The aim of this study was to investigate the association between static scapular positioning and two different PM length measurements in adolescents. Pearson rank test demonstrated that direct measurements of the PM length significantly and strongly inversely correlated to scapular anterior tilting (p = .01; r = −.592)and significantly and moderately inversely correlated to scapular internal rotation (p = .013; r = −.465) and scapular downward rotation (p = .028; r = −.416). However, indirect measurement of the PM length was not related to scapular posture. No significant correlation was found between direct and indirect PM length measurements. Direct measurement of PM length presents more information regarding alterations of the static scapular positioning.

scholarly journals Passive underwater acoustic evolution of a calving event

2012 ◽  
Vol 53 (60) ◽  
pp. 113-122 ◽  
Author(s):  
Erin C. Pettit
Keyword(s):  
Spectral Characteristics ◽  
Low Frequency ◽  
Acoustic Measurements ◽  
Dynamic Nature ◽  
High Frequencies ◽  
Direct Measurements ◽  
Audible Sound ◽  
Passive Acoustic ◽  
Remotely Sense ◽  
Ocean Boundary

AbstractDirect measurements of processes occurring at the ice–ocean boundary are difficult to acquire because of the dangerous and dynamic nature of the boundary, yet these processes are among the least well understood in glaciology. Because sound travels well through water, passive underwater acoustics offers a method to remotely sense activity at this boundary. Here we present passive acoustic measurements and spectral analysis of the evolution of a subaerial calving event and the subsequent mini-tsunami and seiche at Meares Glacier, Alaska, USA. Using two hydrophones to record sound from 1 to 40 000 Hz, we find that each phase of a calving event has distinctive spectral characteristics. An event begins with an infrasound rumble (1–20 Hz), then the ice fractures (20–100 Hz), falls and impacts the water (200–600 Hz). High-frequency (>10 000 Hz) sound increases in intensity quickly as the iceberg oscillates, creating turbulence, spray and waves. Within 10 s, the low-frequency audible sound dissipates and the mini-tsunami and seiche sounds dominate (infrasound plus high frequencies) and continue for over 10 min. The specific frequencies and duration of each phase of a calving event depend on its size and location and the glacier and fjord characteristics.

A device for indirect measurements: An entertaining individual project

1973 ◽  
Vol 20 (2) ◽  
pp. 124-127
Author(s):  
William Patterson
Keyword(s):  
Indirect Measurement ◽  
Indirect Measurements ◽  
Individual Project

Indirect measurement is often studied in geometry courses. Usually textbook examples and exercises involving the measurement of the heights of objects are presented. Very seldom, though, do students actually make indirect measurements. The purpose of this article is to outline the construction and use of a device to measure the heights of objects. The device will enable students to actually make indirect measurements and thus appreciate the fact that there are applications of the mathematics they study in class.

Acoustic Measurement of Subglottic Stenosis

1996 ◽  
Vol 105 (7) ◽  
pp. 504-509 ◽  
Author(s):  
Judith M. Czaja ◽  
Thomas V. McCaffrey
Keyword(s):  
Strong Correlation ◽  
Subglottic Stenosis ◽  
Acoustic Measurement ◽  
Sectional Area ◽  
Acoustic Measurements ◽  
Cross Sectional ◽  
Direct Measurements ◽  
Efficacy Of Treatment ◽  
Stenotic Segment

A device that determines cross-sectional area (CSA) of the airway by acoustic ref lections (Hood, Inc) was used to measure subglottic area. Airway models were made from Plexiglas rings with known internal dimensions similar to clinically encountered stenoses of various lengths and diameters. Acoustic measurements of airway area were made and compared to actual CSA. There is a strong correlation between CSA measured acoustically and the actual area of simulated stenoses. However, when the CSA of the stenosis was <0.64 cm2, the signal was impaired, resulting in overestimation of the stenotic CSA. In simulated stenoses with a CSA of <0.38 cm2, acoustic measurement of the CSA beyond the stenotic segment was unreliable. Determination of the origin of stenosis was accurate with this method. The CSA of cadaver airways was also measured acoustically. The CSA 2.0 cm below the glottis of normal airways in males ranged from 1.28 to 2.74 cm2 and in females 0.87 to 1.43 cm2, with means of 2.16 and 1.09 cm2. It appears that acoustic measurement of CSA of subglottic stenosis is a feasible clinical technique that yields dimensions of the airway in situations in which direct measurements are impossible. It was suggested that this technique be used for assessment of subglottic stenosis and evaluation of the efficacy of treatment of subglottic stenosis.

scholarly journals Improved evaluation of uncertainty for indirect measurement

ACTA IMEKO ◽  
2017 ◽  
Vol 6 (2) ◽  
pp. 89 ◽  
Author(s):  
Valeriy Ivanovich Didenko
Keyword(s):  
Total Error ◽  
Indirect Measurement ◽  
Analog To Digital Converters ◽  
Uncertainty Evaluation ◽  
Analog To Digital ◽  
Measuring Devices ◽  
Direct Measurements ◽  
Different Types

<p class="Abstract"><span lang="EN-US">The paper gives formulae for uncertainty evaluation of an indirect measurement based on direct measurements made by different types of measuring devices. The first type of the measuring devices has the specifications of a total error (e.g. digital instruments), while the second type has the specifications of offset, gain and linearity errors (e.g. analog to digital converters). The choice of a device range and the configuration of measuring circuits for decreasing uncertainty are considered. The conversion of the specifications for the first type to the specifications for the second type is discussed.</span></p>

scholarly journals An MLP-ANN-based approach for assessing nitrate contamination

2019 ◽  
Vol 19 (7) ◽  
pp. 1911-1917 ◽  
Author(s):  
Maria Laura Foddis ◽  
Augusto Montisci ◽  
Fatma Trabelsi ◽  
Gabriele Uras
Keyword(s):  
Neural Networks ◽  
Electrical Conductivity ◽  
Laboratory Tests ◽  
Nitrate Concentration ◽  
Nitrate Contamination ◽  
Multi Layer Perceptron ◽  
Indirect Measurements ◽  
Direct Measurements ◽  
Ann Models ◽  
Cost Efficient

Abstract This paper investigates the feasibility of predicting nitrate contamination from agricultural sources using multi-layer perceptron artificial neural networks (MLP-ANNs). The approach consists in training an MLP-ANN to predict nitrate concentrations based on a set of indirect measurements, such as pH, electrical conductivity, temperature and groundwater level. These are simpler and more economical than direct measurements, and they can be continuously collected on-site, rather than by performing laboratory tests. The approach has been validated in the nitrate vulnerable zone of the Arborea plain (central western Sardinia, Italy) by comparing the results obtained with different MLP-ANN models in order to find the most efficient model. The results show that the MLP-ANN-based model is a time- and cost-efficient method for predicting nitrate concentration.

Estimation of the error of the results of indirect measurements of some quantities

2020 ◽  
pp. 18-24
Author(s):  
E.V. Eremin
Keyword(s):  
Taylor Series ◽  
Analytical Formula ◽  
Sufficient Conditions ◽  
Nonlinear Function ◽  
Degree Of Approximation ◽  
Necessary And Sufficient Conditions ◽  
Indirect Measurements ◽  
Direct Measurements ◽  
Relative Errors ◽  
Necessary And Sufficient

The basic mathematical provisions that determine the necessary and sufficient conditions for the application of the method of linearization of nonlinear functions of random arguments in the evaluation of errors of the results of indirect measurements are considered, and the need to present the assessment of the arising systematic component of the error and the degree of approximate representation of functions is noted. Within the framework of the necessary and sufficient conditions for the expansion of an arbitrary function into a Taylor series, a new analytical formula for the approximation of a nonlinear function in the form of a quotient of independent random arguments is obtained, which allows to exclude the questions of refinement of the results by adding terms to the Taylor series and estimating the degree of approximation of a nonlinear function by the values of the corresponding residual terms when evaluating the errors of indirect measurements. It is shown that the obtained new approximation for the replacement of such a function allows us to determine the practical conditions under which to estimate the errors of the corresponding results it is possible to use known, and quite simple, formulas for estimating the absolute and relative errors without preprocessing the results of direct measurements.

Blading Vibration and Failures in Gas Turbines: Part C — Detection and Troubleshooting

1995 ◽  
Author(s):  
Cyrus B. Meher-Homji
Keyword(s):  
Gas Turbines ◽  
Failure Modes ◽  
Measurement Techniques ◽  
Indirect Measurement ◽  
Qualitative Information ◽  
Part C ◽  
Microstructure Changes ◽  
Direct Measurements ◽  
Blade Failure

Blade failures account for as many as 42% of failures in gas turbines. This paper covers approaches to detect and avoid blade failures by direct and indirect measurement techniques. Direct measurements involve the use of special sensors or methods that measure blading vibration or condition. Indirect techniques do not quantitatively measure blade conditions but provide qualitative information that help in avoiding blade problems. Metallurgical tests of hot section blades to determine microstructure changes are also covered. A blade failure troubleshooting chart is furnished to assist users in diagnosing common failure modes.

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