Advanced Techniques for Determining High and Extreme High Damping: OMI - A New Algorithm to Compute the Logarithmic Decrement

2006 ◽  
Vol 319 ◽  
pp. 231-0 ◽  
Author(s):  
A. Stanislawczyk
Keyword(s):  
High Precision ◽  
Relative Error ◽  
Logarithmic Decrement ◽  
Mechanical Loss ◽  
Harmonic Oscillations ◽  
Experimental Conditions ◽  
Damping Materials

A new algorithm OMI (Optimization in Multiple Intervals) for the computation of the logarithmic decrement from exponentially damped harmonic oscillations is described. This method is shown to be effective and computationally compact for high damping materials. A comparison between the OMI algorithm and the four classical methods usually used in the computation of the logarithmic decrement is reported. The OMI algorithm yields high precision in the computation of the logarithmic decrement and the smallest dispersion of experimental points on the plots of mechanical loss spectra. The effect of the acquisition parameters and the experimental conditions on the results of computations of the logarithmic decrement and the relative error is discussed.

Determination of the Logarithmic Decrement in Mechanical Spectroscopy

2006 ◽  
Vol 115 ◽  
pp. 7-14 ◽  
Author(s):  
Leszek B. Magalas
Keyword(s):  
Resonant Frequency ◽  
High Precision ◽  
Logarithmic Decrement ◽  
Mechanical Spectroscopy ◽  
Harmonic Oscillations

The comparison between the classical methods and a new algorithm OMI used to compute the logarithmic decrement is reported. The OMI algorithm is tested in the computation of the logarithmic decrement from exponentially damped harmonic oscillations. The OMI algorithm yields high precision in the computation of the logarithmic decrement and the resonant frequency, and the smallest dispersion of experimental points.

On-Line Control of Harmonic Oscillations in a Low-Frequency Resonant Mechanical Spectrometer

2006 ◽  
Vol 115 ◽  
pp. 299-304
Author(s):  
Leszek B. Magalas ◽  
A. Piłat
Keyword(s):  
Real Time ◽  
High Precision ◽  
Low Frequency ◽  
Control Unit ◽  
High Accuracy ◽  
Mechanical Loss ◽  
Harmonic Oscillations ◽  
Excitation Process ◽  
On Line ◽  
Short Time

The on-line control unit is used to ensure high-accuracy computations of the logarithmic decrement. It is shown that the excitation process should be on-line low level real-time controlled during mechanical loss measurements to obtain high precision of the computations and to ensure a short-time excitation process.

Zero-Point Drift in Low-Frequency Mechanical Spectroscopy

2006 ◽  
Vol 115 ◽  
pp. 285-292 ◽  
Author(s):  
Leszek B. Magalas ◽  
A. Piłat
Keyword(s):  
Low Frequency ◽  
Zero Point ◽  
Logarithmic Decrement ◽  
Torsion Pendulum ◽  
Mechanical Spectroscopy ◽  
Mechanical Loss ◽  
Harmonic Oscillations

The concept of the ‘zero-point drift’, ZPD, is introduced and analyzed on the basis of mechanical loss measurements carried out in a low-frequency mechanical spectrometer – inverted torsion pendulum. It is demonstrated that the ZPD, which modifies damped harmonic oscillations leads to false values of the logarithmic decrement computed from several widely accepted algorithms.

Continuous and simultaneous measurement of triple oxygen and hydrogen isotopes of liquid and vapour during evaporation

2020 ◽  
Author(s):  
Matthew Brady ◽  
David Hodell
Keyword(s):  
High Precision ◽  
Standard Error ◽  
Numerical Models ◽  
Hydrogen Isotopes ◽  
Vapour Phase ◽  
Integration Time ◽  
Experimental Conditions ◽  
Liquid Injection ◽  
Oxygen And Hydrogen Isotopes ◽  
The Mean

<p>Here, we describe a system for measuring triple oxygen and hydrogen isotopic ratios of both the liquid and vapour during evaporation of water in a dry gas stream (N2 or dry air) at constant temperature and relative humidity (RH).  The hardware consists of a polymer glove box (COY), peristaltic pump (Ismatec), and Picarro L2140-i cavity ring-down laser spectrometer (CRDS) with Standard Delivery Module (SDM). Liquid water from the evaporation pan is sampled via a closed recirculating loop and syringe pump that delivers a constant rate of water to the vaporizer, maintaining a constant concentration of water vapour in the cell (20,000 ±103, 1 s.d.) over an injection cycle. Liquid measurements alternate with vapour from the glove box which is introduced to the CRDS using a diaphragm gas pump. Important for high-precision measurements, both cavity pressure and outlet valve stability are maintained throughout the liquid injection and subsequent vapour phase. Experiments are bookended by two in-house standards which are calibrated to the SMOW-SLAP scales. An additional drift corrector is introduced periodically.</p><p> </p><p>To test the precision and stability of the liquid injections, we sampled from an isotopically homogeneous volume of water and introduced it to the cavity over a period of ~48h. To minimise the standard deviation derived from noise, we chose an optimum integration time of ~2000s (~33 minutes) based on σ<sub>Allan </sub>minimisation. Therefore, for combined liquid-vapour experiments we use an injection/vapour sampling window of 40-minutes (140ug water is consumed per injection), which provides a data collection period of 33-minutes after a 7-min waiting time for equilibration.</p><p> </p><p>Across a single liquid injection, the mean standard error for d<sup>17</sup>O, d<sup>18</sup>O, and dD is 0.008‰, 0.007‰, and 0.02‰, respectively. For the vapour phase equivalent, the mean standard error for d<sup>17</sup>O, d<sup>18</sup>O, and dD is 0.01‰, 0.009‰, 0.03‰ respectively. For the d-excess in the liquid and the vapour across one 33-minute cycle, the standard error is 0.07‰ and 0.08‰, respectively. For the O17-excess in the liquid and the vapour across one 33-minute cycle, the standard error is 6 per meg and 8 per meg, respectively.</p><p> </p><p>A single evaporation experiment produces in excess of 100,000 measurements each of d<sup>17</sup>O, d<sup>18</sup>O, and dD for both the evaporating liquid and resulting vapour. These measurements result in 95% confidence limits for the slope of ln(d<sup>17</sup>O+1) vs ln(d<sup>18</sup>O+1) of ±0.0002 and ±0.0003 for the liquid and vapour, respectively.  For the slope of ln(dD+1) vs ln(d<sup>18</sup>O+1) we obtain a 95% confidence interval of ±0.001 and ±0.002 for the liquid and vapour, respectively. The experimental method permits measurement of fractionation of triple oxygen and hydrogen isotopes of water under varying experimental conditions (e.g., RH, temperature, turbulence) at very high precision. It will be useful for testing numerical models of evaporation and conducting experiments to simulate evaporation and isotopic equilibration in natural systems. An application to closed-basin lakes will be presented.</p>

THE INFLUENCE OF VIBRATION DAMPING MATERIALS' COMPOSITION ON THEIR MECHANICAL LOSS FACTOR

2015 ◽  
Vol 0 (10) ◽  
pp. 10-10 ◽  
Author(s):  
V.A. Sagomonova ◽  
◽  
V.I. Kislyakova ◽  
T.Yu. Tyumeneva ◽  
V.A. Bolshakov ◽  
...  
Keyword(s):  
Loss Factor ◽  
Vibration Damping ◽  
Mechanical Loss ◽  
Damping Materials ◽  
Mechanical Loss Factor

scholarly journals Low-Latency and Minor-Error Architecture for Parallel Computing XY-Like Functions with High-Precision Floating-Point Inputs

Electronics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 69
Author(s):  
Ming Liu ◽  
Wenjia Fu ◽  
Jincheng Xia
Keyword(s):  
High Precision ◽  
Relative Error ◽  
State Of The Art ◽  
Latency Period ◽  
Limited Range ◽  
The State ◽  
Floating Point ◽  
Cordic Algorithm ◽  
Maximum Relative Error ◽  
Large Area

This paper proposes a novel architecture for the computation of XY-like functions based on the QH CORDIC (Quadruple-Step-Ahead Hyperbolic Coordinate Rotation Digital Computer) methodology. The proposed architecture converts direct computing of function XY to logarithm, multiplication, and exponent operations. The QH CORDIC methodology is a parallel variant of the traditional CORDIC algorithm. Traditional CORDIC suffers from long latency and large area, while the QH CORDIC has much lower latency. The computation of functions lnx and ex is accomplished with the QH CORDIC. To solve the problem of the limited range of convergence of the QH CORDIC, this paper employs two specific techniques to enlarge the range of convergence for functions lnx and ex, making it possible to deal with high-precision floating-point inputs. Hardware modeling of function XY using the QH CORDIC is plotted in this paper. Under the TSMC 65 nm standard cell library, this paper designs and synthesizes a reference circuit. The ASIC implementation results show that the proposed architecture has 30 more orders of magnitude of maximum relative error and average relative error than the state-of-the-art. On top of that, the proposed architecture is also superior to the state-of-the-art in terms of latency, word length and energy efficiency (power × latency × period /efficient bits).

scholarly journals Study on the tool setting method of micro-milling tool based on in-line holography

2022 ◽  
Vol 355 ◽  
pp. 03069
Author(s):  
Xianghui Zhang ◽  
Jinkai Xu ◽  
Zhanjiang Yu ◽  
Huadong Yu
Keyword(s):  
High Precision ◽  
Relative Error ◽  
Micro Milling ◽  
Milling Tool ◽  
Measurement Results ◽  
Tool Setting ◽  
Micro Tool ◽  
Key Issues ◽  
Holographic Measurement ◽  
Five Axis

Aiming at the various shortcomings of existing tool setting methods, this paper proposes a coaxial holographic tool setting method for tiny tools. Based on the research and analysis of the principle of holographic imaging and the key issues of holographic images, a set of holographic tool setting detection device for micro milling tool was built, and the micro milling tool measurement was carried out on the five-axis machining center using standard tools. experiment. Experimental results show that the tool setting device can efficiently perform tool setting detection of micro-milling tool. Compared with the measurement results of the high-precision external presetting instrument, the relative error of the contact tool setting instrument is 0.033%, and the relative error of the holographic tool setting prototype is 0.007%, which is more effective in realizing the tool setting of tiny tools. Detection. This result verifies the feasibility of the coaxial holographic tool setting method for micro tool, that is, holographic measurement can be used for high-precision tool setting of micro milling tool.

scholarly journals Estimating the Volume of Oil Tanks Based on High-Resolution Remote Sensing Images

2019 ◽  
Vol 11 (7) ◽  
pp. 793
Author(s):  
Tong Wang ◽  
Ying Li ◽  
Shengtao Yu ◽  
Yu Liu
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
High Precision ◽  
Relative Error ◽  
Absolute Error ◽  
Optical Remote Sensing ◽  
Practical Applications ◽  
Oil Tank ◽  
Actual Height ◽  
Oil Tanks

The purpose of this study is to obtain oil tank volumes from high-resolution satellite imagery to meet the need to measure oil tank volume globally. A preprocessed remote sensing HSV image is used to extract the shadow of the oil tank by Otsu thresholding, shadow area thresholding, and morphological closing. The oil tank shadow is crescent-shaped. Hence, a median method based on sub-pixel subdivision positioning is used to calculate the shadow length of the oil tank and then determine its height with high precision. The top of the tank and its radius in the image are identified using the Hough transform. The final tank volume is calculated using its height and radius. A high-resolution Gaofen 2 optical remote sensing image is used to evaluate the proposed method. The actual height and volume of the tank we tested were 21.8 m and 109,532 m3. The experimental results show that the mean absolute error of the height of the tank calculated by the median method is 0.238 m, the relative error is within 1.15%, and the RMES is 0.23. The result is better than the previous work. The absolute error between the calculated and the actual tank volumes ranges between 416 and 3050 m3, and the relative error ranges between 0.38% and 2.78%. These results indicate that the proposed method can calculate the volume of oil tanks with high precision and sufficient accuracy for practical applications.

scholarly journals Development of a Smartphone-Based Fluorescent Immunochromatographic Assay Strip Reader

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4521
Author(s):  
Qi Zheng ◽  
Huihuang Wu ◽  
Haiyan Jiang ◽  
Jiejie Yang ◽  
Yueming Gao
Keyword(s):  
High Precision ◽  
Relative Error ◽  
Image Sensors ◽  
Immunochromatographic Assay ◽  
Maximum Relative Error ◽  
Excitation Light ◽  
Detection Range ◽  
Cmos Image Sensors ◽  
Linear Detection ◽  
Optical Module

Fluorescence immunochromatographic assay (FICA) is a rapid immunoassay technique that has the characteristics of high precision and sensitivity. Although image FICA strip readers have the advantages of high portability and easy operation, the use of high-precision complementary metal oxide semiconductor (CMOS) image sensors leads to an increase in overall cost. Considering the popularity of CMOS image sensors in smartphones and their powerful processing functions, this work developed a smartphone-based FICA strip reader. An optical module suitable for the test strips with different fluorescent markers was designed by replacing the excitation light source and the light filter. An android smartphone was used for image acquisition and image denoising. Then, the test and control lines of the test strip image were recognized by the sliding window algorithm. Finally, the characteristic value of the strip image was calculated. A linear detection range from 10 to 5000 mIU/mL (R2 = 0.95) was obtained for human chorionic gonadotrophin with the maximum relative error less than 9.41%, and a linear detection range from 5 to 4000 pg/mL (R2 = 0.99) was obtained for aflatoxin B1, with the maximum relative error less than 12.71%. Therefore, the smartphone-based FICA strip reader had high portability, versatility, and accuracy.

Damping Capacities of B/Al Composite Subjected to Thermal-Mechanical Cycling

2007 ◽  
Vol 561-565 ◽  
pp. 679-682
Author(s):  
Yao Chun Qin ◽  
S.Y. He
Keyword(s):  
Temperature Interval ◽  
Logarithmic Decrement ◽  
Mechanical Loss ◽  
Mechanical Cycling ◽  
Present Test ◽  
Damping Behavior ◽  
Al Composite ◽  
Applied Stresses

The damping capacities of B/Al composite subjected to thermal-mechanical cycling (TMC) were studied. The damping capacities, including the mechanical loss Q-1 and the logarithmic decrement δ , increase with increasing the TMC cycles. The damping capacities of B/Al composite increase more greatly under the elevated applied stresses at the same temperature interval and cycles. After the TMC, the damping capacities can increase 10 times than that of as-fabricated B/Al composite. The damping behavior of B/Al composite under the present test condition is primarily associated with the interfacial degradation during the TMC.

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