Algorithm to Correct Measurement Offsets Introduced by Inactive Elements of Transducer Arrays in Ultrasonic Flow Metering

Ultrasonic flow meters (UFMs) based on transducer arrays offer several advantages. With electronic beam steering, it is possible to tune the steering angle of the beam for optimal signal-tonoise ratio (SNR) upon reception. Moreover, multiple beams can be generated to propagate through different travel paths, covering a wider section of the flow...

Innovative permanent down-hole scale and corrosion monitoring system using ultrasound guided waves technology

Scale and corrosion affect the production certainty of oil and gas well. Scale build-up reduces flow and ultimately could shut down production when it block to tubing completely. Corrosion of the tubing wall occurs very often simultaneously with scale build-up and affects the integrity of the tubing wall. Vital information about the integrity is...

Nanostructured dielectric surfaces for Raman spectroscopy: Design and thermal analysis

In this paper, an all-dielectric metasurface for surface enhanced Raman spectroscopy (SERS) is presented. The proposed design constitutes of an array of silicon (Si) dimers on top of thin film of silicon nitride (SiN), deposited on a glass substrate. The coupling mechanism between the dimers is based on two orthogonal guided waves in the SiN...

Travelling standing waves: A feasibility study

Lately, there has been significant interest in the noninvasive manipulation of particles and liquids. The reported acoustic methods rely on either the acoustic radiation force or acoustic streaming. The latter can be used in developed flows to induce fluid velocities angled to the liquid flow direction. These methods often use standing wave...

1-D profiling using highly dispersive guided waves

Corrosion is one of the industries major issues regarding the integrity of assets. Currently, inspections are conducted at regular intervals to ensure a sufficient integrity level of these assets. Cost reduction while maintaining a high level of reliability and safety of installations is a major challenge. There are many situations where the...

A depth-dependent formula for shallow water propagation

In shallow water propagation, the sound field depends on the proximity of the receiver to the sea surface, the seabed, the source depth, and the complementary source depth. While normal mode theory can predict this depth dependence, it can be computationally intensive. In this work, an analytical solution is derived in terms of the Faddeeva...

Recent developments in guided wave travel time tomography

The concept of predictive maintenance using permanent sensors that monitor the integrity of an installation is an interesting addition to the current method of periodic inspections. Guided wave tomography had been developed to create a map of the wall thickness using the travel times of guided waves. It can be used for both monitoring and for...

3-D reconstruction of sub-wavelength scatterers from the measurement of scattered fields in elastic waveguides

In nondestructive testing, being able to remotely locate and size defects with good accuracy is an important requirement in many industrial sectors, such as the petrochemical, nuclear, and aerospace industries. The potential of ultrasonic guided waves is well known for this type of problem, but interpreting the measured data and extracting...

Refraction measurements and modeling over the Chesapeake Bay during the NATO (TG-51) SAPPHIRE trials, June 2006

Optical refraction tends to occur frequently in the atmospheric boundary layer. Due to a gradient in the temperature as function of height, rays are bending down towards the earth (super-refraction), or up towards to the sky (sub-refraction). As a consequence, images of targets at long range may be distorted and mirages may occur, while the...

VAMPIRA - Radar and Infrared Propagation Synergism Trial

In a coastal environment simultaneous exploitation of radar and infrared sensors and multisensor fusion can overcome the difficulties imposed by the atmospheric conditions with respect to target detection/recognition/classification by the individual sensors. To investigate the so-called radar and infrared synergism with respect to propagation in...

RF propagation measurement and model validation during RF/IR synergy trial vampira

The member nations of AC/323 SET-RTG056/RTG32 on Integration of Radar and Infrared for Ship Self Defence have performed the Validation Measurements for Propagation in the Infrared and Radar (VAMPIRA). The objective was to get insight into the radar and infrared synergy concentrated on propagation in a coastal environment including horizontal...

The red experiment: An assessment of boundary layer effects in a trade winds regime on microwave and infrared propagation over the sea

The Rough Evaporation Duct (RED) experiment was performed off of the Hawaiian Island of Oahu from late August to mid-September 2001 to test the hypothesis that a rough sea surface modifies the evaporation duct. Two land sites were instrumented, one with microwave receivers and the other with an infrared receiver. Two bouys were deployed, a small...

Development of the mediterranean extinction code (MEDEX)

The performance of electro-optical systems can be substantially affected by aerosol particles that scatter and absorb electromagnetic radiation. The model that is most frequently used for the prediction of aerosols and their effect on extinction in the marine atmosphere is the US Navy Aerosol Model (NAM). However, NAM can be significantly less...

Influence de la couche atmospherique marine sur la propagation electromagnetique

The assessment of refractive effects requires a detailed knowledge of the vertical profiles of temperature, humidity and pressure, generally supplied by micro-meteorological (bulk) models. Such models only apply to the surface layer, and do not take into account the particularities of the lower marine atmosphere, such as the presence of waves...