Guided Waves Measurement Techniques in Pitch-Catch Configuration

2020 ◽  
Author(s):  
Francesco Cordella ◽  
Francesco Bertoncini ◽  
Mauro Cappelli
Keyword(s):  
Experimental Investigation ◽  
Theoretical Analysis ◽  
Experimental Method ◽  
Long Range ◽  
Guided Waves ◽  
Measurement Techniques ◽  
Theoretical Background ◽  
Experimental Results ◽  
Discharge Pipe ◽  
Different Types

Abstract Guided waves testing allows a long-range screening in pipes of different types and represents an effective and powerful non-destructing technique for defect detections using a limited number of points of measures. After the characterization through a general theoretical analysis, the focus is set to a real steam discharge pipe with a high mechanical complexity used for many years in a research plant now dismissed. The experimental method applied here is the pitch-catch configuration of two magnetostrictive sensors. The objective of this paper is to establish a strong theoretical background to pave the way for a robust experimental investigation. Preliminary experimental results are consistent with the theoretical analysis.

Guided Waves in Pitch-Catch Configuration: A Theoretical Framework to Steer Toward Experimental Tests

2020 ◽  
Author(s):  
Francesco Cordella ◽  
Mauro Cappelli ◽  
Francesco Bertoncini
Keyword(s):  
Theoretical Analysis ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Guided Waves ◽  
Oil And Gas ◽  
Theoretical Background ◽  
Guided Wave ◽  
Nuclear Industry ◽  
Discharge Pipe

Abstract Guided waves testing allows a long-range screening in pipes of different types and represents an effective and powerful non-destructing technique for defect detections using a limited number of points of measures. This kind of testing hence represents an appealing technique not only for the Oil and Gas industries but also for the Nuclear Industry, in particular regarding the Structural Health Monitoring of Nuclear Power Plants components. Another point of strength of this technique is that it can be applied in different configurations as the pulse-echo (the same probe is used both for transmission and signal receiving) or the pitch-catch (two symmetric probes are used one for the signal transmission and the second one for the signal receiving). In this way, the guided wave testing with magnetostrictive sensors can be reliably used for the short and long-term monitoring of Nuclear Power Plants components. The objective of this paper is to establish a strong theoretical background to pave the way for a robust experimental investigation. In particular, after the characterization through a general theoretical analysis, the focus is on a real steam discharge pipe with a high mechanical complexity used for many years in a research facility and now dismissed. The experimental method applied is the pitch-catch configuration of two magnetostrictive sensors. Preliminary experimental results conducted on a real complex steam discharge pipe are consistent with the theoretical analysis.

Guided Waves as an Online Monitoring Technology for Long-Term Operation in Nuclear Power Plants: Experimental Results on a Steam Discharge Pipe

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Mauro Cappelli ◽  
Francesco Cordella ◽  
Francesco Bertoncini ◽  
Marco Raugi
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Guided Waves ◽  
Complex Structure ◽  
Theoretical Background ◽  
Guided Wave ◽  
Experimental Results ◽  
Term Operation

Guided wave (GW) testing is regularly used for finding defect locations through long-range screening using low-frequency waves (from 5 to 250 kHz). By using magnetostrictive sensors, some issues, which usually limit the application to nuclear power plants (NPPs), can be fixed. The authors have already shown the basic theoretical background and simulation results concerning a real steel pipe, used for steam discharge, with a complex structure. On the basis of such theoretical framework, a new campaign has been designed and developed on the same pipe, and the obtained experimental results are now here presented as a useful benchmark for the application of GWs as nondestructive techniques. Experimental measures using a symmetrical probe and a local probe in different configurations (pulse-echo and pitch-catch) indicate that GW testing with magnetostrictive sensors can be reliably applied to long-term monitoring of NPPs components.

Guided Waves As an Online Monitoring Technology for Long Term Operation in NPPs: New Experimental Results on a Steam Discharge Pipe

2017 ◽  
Author(s):  
Francesco Bertoncini ◽  
Mauro Cappelli ◽  
Francesco Cordella ◽  
Marco Raugi
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Guided Waves ◽  
Complex Structure ◽  
Theoretical Background ◽  
Guided Wave ◽  
Experimental Results ◽  
Primary Circuit ◽  
Term Operation

Guided Wave (GW) testing is regularly used for finding defect locations through long range screening using low-frequency waves (from 5 to 250 kHz) [1]-[3]. Magnetostrictive sensors can overcome some issues, which usually limit the application to Nuclear Power Plants (NPPs) [4], like for example, high temperatures [5]-[6], high wall thickness of components in the primary circuit, and characteristic defect typologies. The authors have already shown the basic theoretical background, some simulations and some first experimental results concerning a real steel pipe, used for steam discharge, having a complex structure. Collecting more experimental data with a novel test campaign on the same pipe its complex structure results as a useful benchmark for the application of GWs as Non Destructive Techniques (NDT). Experimental measures using a symmetrical probe and a local probe in different configurations (pulse-echo and pitch-catch) indicate that GW testing with magnetostrictive sensors can be reliably applied to long-term monitoring of NPP components.

Fundamental Study on Needleless Electrospinning Based on Metal (Card) Clothing

2013 ◽  
Vol 662 ◽  
pp. 103-107
Author(s):  
Yan Bo Liu ◽  
Ze Ru Zhang ◽  
Peng Cheng Li ◽  
Velmurugan Thavasi
Keyword(s):  
Theoretical Analysis ◽  
Polyvinyl Alcohol ◽  
Scaling Up ◽  
Electrospinning Process ◽  
Experimental Results ◽  
Fundamental Study ◽  
Needleless Electrospinning ◽  
Electrospinning Method ◽  
New Process ◽  
Different Types

This paper discloses a method for producing nanofibers by a needleless electrospinning process based on the metal (card) clothing. 20% w/w polyvinyl alcohol (PVA) solution was employed to demonstrate the feasibility of this new electrospinning technology. Different types of metal clothing were used to produce PVA nanofibers under different voltages in the experiments; theoretical analysis of this new electrospinning method was also carried out to understand the experimental results. The results indicated the great potential for scaling up this new avenue for producing nanofibers through electrospinning, especially when medium sized clothing was used in the new process.

scholarly journals Long-range versus short-range effects in cold molecular ion-neutral collisions

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Alexander D. Dörfler ◽  
Pascal Eberle ◽  
Debasish Koner ◽  
Michał Tomza ◽  
Markus Meuwly ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Theoretical Analysis ◽  
Ab Initio ◽  
Long Range ◽  
Short Range ◽  
Experimental Results ◽  
Quantum Scattering ◽  
Kinetics And Dynamics ◽  
Reaction Channels ◽  
Ab Initio Potentials

AbstractThe investigation of cold interactions between ions and neutrals has recently emerged as a new scientific frontier at the interface of physics and chemistry. Here, we report a study of charge-transfer (CT) collisions of Rb atoms with N$${}_{2}^{+}$$2+ and O$${}_{2}^{+}$$2+ ions in the mK regime using a dynamic ion-neutral hybrid trapping experiment. We observe markedly different CT kinetics and dynamics for the different systems and reaction channels studied. While the kinetics in some channels are consistent with classical capture theory, others show distinct non-universal dynamics. The experimental results are interpreted with the help of classical-capture, quasiclassical-trajectory and quantum-scattering calculations using ab-initio potentials for the highly excited molecular states involved. The theoretical analysis reveals an intricate interplay between short- and long-range effects in the different reaction channels which ultimately determines the CT dynamics and rates. Our results illustrate salient mechanisms that determine the efficiency of cold molecular CT reactions.

Experimental Investigation of a System With Multiple Nearly Identical Centrifugal Pendulum Vibration Absorbers

2003 ◽  
Author(s):  
Tyler M. Nester ◽  
Alan G. Haddow ◽  
Steven W. Shaw
Keyword(s):  
Experimental Investigation ◽  
Theoretical Background ◽  
Experimental Results ◽  
Circular Path ◽  
Vibration Absorbers ◽  
Test Apparatus ◽  
Controlled Experiments ◽  
Theoretical Predictions ◽  
Centrifugal Pendulum Vibration Absorbers ◽  
First Time

This paper presents experimental results from tests completed on a rotor system fitted with nearly-identical circular path centrifugal pendulum vibration absorbers. A brief review of theoretical background for the absorbers is given along with an overview of the test apparatus. The experimental results for one absorber and for four absorbers are presented and compared with theoretical predictions and expectations. To the best knowledge of the authors, this is the first time that systematic, controlled experiments that monitored both the response of the absorbers and the rotor have been undertaken.

Experimental investigation and theoretical analysis of tear propagation of GQ-6 airship envelope

2016 ◽  
Vol 48 (1) ◽  
pp. 304-321 ◽  
Author(s):  
Fengxin Wang ◽  
Yonglin Chen ◽  
Guangzhong Liu ◽  
Zhengming Guo ◽  
Gongyi Fu
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Theoretical Analysis ◽  
Crack Length ◽  
Load Ratio ◽  
Initial Crack ◽  
Experimental Results ◽  
Crack Orientation ◽  
Initial Crack Length ◽  
Critical Energy Release Rate

This paper reports the central tearing properties of a new airship envelope fabric, GQ-6, from experimental investigation and theoretical analysis. First, the effects of the load ratio, the initial crack length, and the crack orientation on the tearing mechanical properties of such material were evaluated. The experimental results revealed that the mechanical properties of GQ-6 decrease with the increase of initial crack length. Two fracture modes were observed, e.g. either along the warp or the weft yarns directions, which depend on crack orientation and load ratio. Oriented crack can be represented by non-oriented crack with crack equivalent length under biaxial condition. The toughness KIC for the fabric was determined based on experimental results, as well as critical energy release rate GIC. A comparison of the mechanical behaviors of this textile under uniaxial and biaxial tensile condition is also presented. The allowable crack length for GQ-6 envelope fabric during working condition is estimated.

Experimental Investigation of the Biaxial Load-Extension Properties of Plain, Weft-Knitted Fabrics

1977 ◽  
Vol 47 (4) ◽  
pp. 233-239 ◽  
Author(s):  
Brian M. Macrory ◽  
J. Roger Mccraith ◽  
A. B. McNamara
Keyword(s):  
Experimental Investigation ◽  
Theoretical Analysis ◽  
Experimental Results ◽  
Knitted Fabric ◽  
Knitted Fabrics ◽  
Test Instrument ◽  
Biaxial Load ◽  
Theoretical Predictions ◽  
End Use ◽  
Good Agreement

A test instrument is described which permits measurement of load and extension along the courses and wales of a knitted fabric as the latter is being extended in both directions simultaneously. The rates of extension may be chosen to deform the fabric in a variety of modes representative of end-use situations. Experimental results obtained for plain, weft-knitted fabrics using three different hosiery yarns are presented. Comparison is made with values predicted by the authors' theoretical analysis of the biaxially-loaded fabric configuration, and good agreement between the experimental results and the theoretical predictions is obtained.

PHOTOINDUCED NONLINEAR OCTUPOLAR POLARIZATION: TRANSIENT AND PERMANENT REGIMES

1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS
Keyword(s):  
Theoretical Analysis ◽  
Second Harmonic ◽  
Experimental Results ◽  
Polar Field ◽  
Rotational Spectrum ◽  
Dual Frequency ◽  
One Dimensional ◽  
Ethyl Violet ◽  
Disperse Red 1 ◽  
Good Agreement

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.

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