Markets
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Environmental Observations
CMR contribute to observe our environment through research, technology and product development. We work for effective environmental monitoring in real-time.
Applications
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Investigating the Polar Regions
Reliable technologies for long term operation in extreme environments
Projects
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ICEX - Automatic weather station
CMR delivers automatic observation stations that can be deployed on the ice for environmental and ice drift monitoring.
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Bathymetry Buoy
The Bathymetry Bouy is designed for water depth measurement and satellite data communication of data in harsh arctic environments.
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ES300 - Upward Looking Sonar
The ES300 instrument is an upward looking sonar used in the arctic/antarctic for measuring ice thickness. It has an battery lifetime of 1-5 years. The first versions were made in 1989 continuously developed since.
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Seisdrift
An autonomous drifting seismic buoy for acquisition of single channel seismic reflection data from drifting sea ice in the Arctic Ocean and real-time data transmission to shore via Iridium
Publications
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Transducer finite aperture effects in sound transmission near leaky Lamb modes in elastic plates at normal incidence
Aanes, Magne; Lohne, Kjetil Daae; Lunde, Per; Vestrheim, Magne
The interaction of ultrasonic waves with fluid-embedded viscoelastic plates, pipes, and shells, have been subject to extensive theoretical and experimental studies over several decades. In normal-incidence through-transmission measurements of a water-embedded solid plate using ultrasonic piezoelectric transducer sound fields, significant deviations from plane wave theory have recently been observed.
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Beam transmission of water-embedded steel plate at normal incidence. Diffraction effects in the S1 to A3 region
Aanes, Magne; Lohne, Kjetil Daae; Lunde, Per; Vestrheim, Magne;
Measurement of the sound transmission through a fluid?embedded viscoelastic plate at normal incidence can show significant deviations to the plane?wave theory, experiencing both frequency shift and signal level variation in relation to the plane?wave theory.
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Transducer beam diffraction effects in sound transmission near leaky Lamb modes in elastic plates at normal incidence
Aanes, Magne; Lohne, Kjetil Daae; Lunde, Per; Vestrheim, Magne;
The plane wave theory of fluid-embedded viscoelastic plates is often used in waveguide applications, and to estimate wall thickness and sound velocities in plates and pipe walls. In normal-incidence through-transmission measurements, downward frequency shift, signal amplification, and distorted beam patterns, as compared to plane-wave theory, have been observed for resonant peaks in frequency bands near certain Lamb modes.
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Normal incident ultrasonic beam transmission through a water-immersed plate using a piezoelectric transducer. Finite element modelling, angular spectrum method and measurement
Aanes, Magne; Lohne, Kjetil Daae; Lunde, Per; Vestrheim, Magne;
Accurate time of flight (TOF) measurements in non-invasive ultrasonic applications for media contained by plane walls or pipes, demand a precise understanding and control of the generation, transmission and reception of sound beams through solid layers (plane walls or pipes) and the surrounding fluids.
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Ultrasonic beam transmission through a water-immersed plate at oblique incidence using a piezoelectric source transducer. Finite element - angular spectrum modeling and measurements
Aanes, Magne; Lohne, Kjetil Daae; Lunde, Per; Vestrheim, Magne;
A measurement system consisting of a piezoelectric transducer and a water-immersed steel plate is studied.
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Finite element analysis of acoustic beam interactions with plate at normal incidence. Comparison with a 3D angular spectrum method and measurements
Aanes, Magne; Lohne, Kjetil Daae; Lunde, Per; Vestrheim, Magne;
The use of the fi nite element method (FEM) for studying the interactions of an acoustic beam with an elastic steel plate is discussed, in comparison with a 3D angular spectrum method (ASM) and measurements.
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Measurements and 3D simulation of ultrasonic directive beam transmission through a water-immersed steel plate
Lohne, Kjetil Daae; Lunde, Per; Vestrheim, Magne;
A 3D full-wave angular spectrum simulation model for reflection and transmission of ultrasonic directive circular piston sound fields, from and through a fluid-immersed isotropic solid plate has been implemented.
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Ultrasonic signal transmission in plates – Study of a steel plate immersed in water
Lohne, Kjetil Daae; Lunde, Per; Magne Vestrheim
In the present work, a theory for the description of the propagation of plane ultrasonic waves through a fluid loaded plate is described. The theory assumes different fluid loading at the two interfaces, but the special case with the same fluid loading is also treated.