scholarly journals Nonlinear Suppression of a Dual-Tube Coriolis Mass Flowmeter Based on Synchronization Effect

2021 ◽  
Vol 11 (21) ◽  
pp. 9916
Author(s):  
Zhong-Xiang Li ◽  
Chun Hu ◽  
Ming-Zhe Han ◽  
Shang-Chun Fan ◽  
De-Zhi Zheng
Keyword(s):  
Lagrange Equation ◽  
Frequency Doubling ◽  
Nonlinear Frequency ◽  
Additional Mass ◽  
Suppression Effect ◽  
Coriolis Mass Flowmeter ◽  
Coupling System ◽  
Double Beam ◽  
Measuring Frequency ◽  
Synchronization Effect

Nonlinear interference components exist in the output signals of dual-tube Coriolis mass flowmeters (CMFs) which affect the sensitivity and accuracy of the devices. This nonlinearity still appears under zero flow, which is manifested when the output signal contains a frequency doubling signal. This study (1) investigated an additional-mass method to suppress the nonlinear frequency doubling phenomenon, (2) established a coupling system vibration model with additional mass, built a dynamic differential equation for the vibration of the double-beam coupling system from the Lagrange equation, (3) obtained amplitude frequency information using a fourth-order Runge–Kutta method, (4) determined the suppression effect of the additional mass on the nonlinear frequency doubling phenomenon, and (5) experimentally verified the CMF. The results showed that the base coupled the vibrations of two beams, and the symmetric additional mass suppressed the nonlinear frequency doubling phenomenon, thus suppressing low or high frequencies. Also, the effect of pipeline defects simulated under asymmetric additional mass was obtained through numerical analysis and experimental data. Flowmeters with a required measuring frequency range had the optimal suppression effect on nonlinear frequency doubling and provided theoretical guidance for the nondestructive testing of measuring tubes.

scholarly journals Enhancing Double-Beam Laser Tweezers Raman Spectroscopy (LTRS) for the Photochemical Study of Individual Airborne Microdroplets

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3325 ◽  
Author(s):  
Jovanny Gómez Castaño ◽  
Luc Boussekey ◽  
Jean Verwaerde ◽  
Myriam Moreau ◽  
Yeny Tobón
Keyword(s):  
Raman Spectroscopy ◽  
Optical Tweezers ◽  
Photochemical Reactions ◽  
Laser Tweezers ◽  
New Device ◽  
Spatially Resolved ◽  
Beam Laser ◽  
Coupling System ◽  
Double Beam ◽  
Levitated Droplets

A new device and methodology for vertically coupling confocal Raman microscopy with optical tweezers for the in situ physico- and photochemical studies of individual microdroplets (Ø ≤ 10 µm) levitated in air is presented. The coupling expands the spectrum of studies performed with individual particles using laser tweezers Raman spectroscopy (LTRS) to photochemical processes and spatially resolved Raman microspectroscopy on airborne aerosols. This is the first study to demonstrate photochemical studies and Raman mapping on optically levitated droplets. By using this configuration, photochemical reactions in aerosols of atmospheric interest can be studied on a laboratory scale under realistic conditions of gas-phase composition and relative humidity. Likewise, the distribution of photoproducts within the drop can also be observed with this setup. The applicability of the coupling system was tested by studying the photochemical behavior of microdroplets (5 µm < Ø < 8 µm) containing an aqueous solution of sodium nitrate levitated in air and exposed to narrowed UV radiation (254 ± 25 nm). Photolysis of the levitated NaNO3 microdroplets presented photochemical kinetic differences in comparison with larger NaNO3 droplets (40 µm < Ø < 80 µm), previously photolyzed using acoustic traps, and heterogeneity in the distribution of the photoproducts within the drop.

scholarly journals Dynamic Responses of an Overhead Crane’s Beam Subjected to a Moving Trolley with a Pendulum Payload

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Huasen Liu ◽  
Wenming Cheng ◽  
Yinqi Li
Keyword(s):  
Integral Method ◽  
Lagrange Equation ◽  
Dynamic Responses ◽  
Underactuated System ◽  
Beam Model ◽  
Moving Mass ◽  
Overhead Crane ◽  
Precise Positioning ◽  
Pendulum Swing ◽  
Coupling System

An overhead crane with a flexible cable is an underactuated system; the vibration of the crane’s beam and the residual swinging of the payloads cause fatigue in the crane and affect the precise positioning of the payloads. In this paper, the coupling system of an overhead crane was simplified to that of a moving mass with pendulum swing passing beam model. The differential equation motion of a coupled overhead crane system was derived based on the Lagrange equation. Mathematical solution was carried out by using the Newmark-β integral method. The influences of the trolley’s acceleration and the parameters of the payloads on the vibration of the beam and the payloads’ swing were, respectively, analyzed. A numerical analysis of the results indicates that increasing the mass of the payloads leads to a larger deflection of the beam, whereas increasing the speed and acceleration of the trolley does not obviously influence the maximum deflection of the central beam.

scholarly journals Research on Frequency Doubling Effect of Thermoacoustic Speaker Based on Graphene Film

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6030
Author(s):  
Licheng Deng ◽  
Xingyue He ◽  
Surong He ◽  
Qingying Ren ◽  
Jiang Zhao ◽  
...  
Keyword(s):  
Sound Pressure ◽  
Graphene Film ◽  
Frequency Doubling ◽  
Suppression Effect ◽  
Laser Scribing ◽  
Dc Excitation ◽  
One Step ◽  
Ac Excitation ◽  
Screen Printing Technology ◽  
Good Agreement

In this work, the frequency doubling effect of thermoacoustic speakers is studied, and a method is analyzed to suppress the frequency doubling effect. Three cases were analyzed by superimposing the DC bias on the AC excitation: (1) DC is less than AC; (2) DC is equal to AC; (3) DC is greater than AC. We found that the frequency doubling effect can be well suppressed by superimposing a larger DC excitation on the AC excitation. The laser scribing technology was used to prepare graphene film in only one step, and the screen printing technology was used to prepare conductive electrodes. The microphone and B&K system was used to record the sound pressure level and study the suppression of frequency doubling effect. Finally, the sound pressure levels with the three different kinds of excitations were measured. The measured results show that they have a good agreement with the theoretical results. The suppression effect will be better when DC amplitude is greater than AC amplitude. Therefore, this work has certain reference significance for the further study and application of thermoacoustic speakers.

Experimental analysis of overall thermal properties of Nd:La2CaB10O19crystals

2012 ◽  
Vol 45 (6) ◽  
pp. 1182-1186 ◽  
Author(s):  
Jianxiu Zhang ◽  
Yang Wu ◽  
Guochun Zhang ◽  
Yin Li ◽  
Yicheng Wu
Keyword(s):  
Thermal Expansion ◽  
Rare Earth ◽  
Frequency Conversion ◽  
Frequency Doubling ◽  
Nonlinear Frequency ◽  
Rare Earth Ion ◽  
Nonlinear Frequency Conversion ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Measured Specific Heat

Pure or rare-earth-ion-doped La2CaB10O19(LCB) is a promising optical material for nonlinear frequency conversion, laser and self-frequency doubling applications. In this paper, the thermophysical properties of Nd3+-doped LCB (Nd:LCB) crystals were measured and compared with those of pure and of Yb3+- and Er3+-doped LCB, as well as other borate nonlinear optical crystals. The melting points of rare-earth-doped LCB crystals are lower than that of pure LCB. Thermal expansion coefficients along thea,b,c,c*,a*, 〈110〉 and 〈110〉* directions have been measured, and the principal expansion coefficients were calculated to be 1.85 × 10−6, 4.13 × 10−6and 8.79 × 10−6 K−1. The measured specific heat of Nd:LCB is lower than that of pure LCB, resulting in a larger internal temperature gradient under irradiation by a pulsed laser beam. The measured thermal expansion anisotropy of Nd:LCB is stronger than that of pure LCB. The thermal conductivities of Nd:LCB along thecandc* directions are smaller than those along other crystallographic directions.

scholarly journals Dynamic Modeling and Response of a Rotating Cantilever Beam with a Concentrated Mass

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yang Yong-feng ◽  
Wang Yan-lin ◽  
Chen Hu ◽  
Wu Min-juan
Keyword(s):  
Natural Frequency ◽  
Lagrange Equation ◽  
Concentrated Mass ◽  
Assumed Mode Method ◽  
Damping Characteristics ◽  
Coupling System ◽  
Mode Method ◽  
Position Parameter ◽  
Mass Position ◽  
Assumed Mode

The rigid-flexible coupling system with a hub and concentrated mass is studied in this paper. Considering the second-order coupling of axial displacement which is caused by transverse deformation of the beam, the dynamic equations of the system are established using the second Lagrange equation and the assumed mode method. The simulation results show that the concentrated mass mainly suppresses the vibration and exhibits damping characteristics. When the nondimensional mass position parameterβ>0.67, the first natural frequency is reduced as the concentrated mass increases. Whenβ<0.67, the first natural frequency is increased as the concentrated mass increases. We also find the maximum first natural frequency nondimensional position for the concentrated mass.

scholarly journals Analytical Nonlinear Response for a Rotor with the Hertz Contact and Clearance

Mechanika ◽  
2019 ◽  
Vol 25 (6) ◽  
pp. 473-479
Author(s):  
Zijian ZHANG
Keyword(s):  
Lagrange Equation ◽  
Rotor System ◽  
Phase Portraits ◽  
Theoretical Formula ◽  
Nonlinear Frequency ◽  
Hertz Contact ◽  
Nonlinear Frequency Response ◽  
Attraction Basins ◽  
Stiffness Characteristics ◽  
Good Agreement

This paper focuses on a nonlinear frequency response of a rotor system with power of Hertz contact and piecewise nonlinearities of bearing clearance. A complex equation of motion for this rotor system was deduced using the Lagrange equation. The natural frequency and phase portraits of the unperturbed rotor system were obtained to demonstrate hardening stiffness characteristics. The amplitude frequency and attraction basins of multiple solutions for the perturbed rotatory system without clearance were investigated. The analytical forms of amplitude frequency of the perturbed system with clearance were analyzed. Through numerical simulation, the correctness of the theoretical formula is verified, and it is in good agreement with the numerical results.

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