• A Study of the Ultrasonic Measurements for Logging Behind a Steel Pipe: Expanding the proessing to improve the differentiation between heavy fluids and light solids 

      Sirevaag, Tore Lie (Doctoral theses at NTNU;2019:375, Doctoral thesis, 2020)
      In petroleum applications using acoustic wave theory, the most used practice can be found in borehole geophysical methods, where acoustic logging has long been the foremost source for cement evaluation. Due to stricter ...
    • Analysis of acoustic impedance matching in dual-band ultrasound transducers 

      Myhre, Ola Finneng; Johansen, Tonni Franke; Angelsen, Bjørn Atle J. (Journal article; Peer reviewed, 2017)
      Dual-frequency band probes are needed for ultrasound (US) reverberation suppression and are useful for image-guided US therapy. A challenge is to design transducer stacks that achieve high bandwidth and efficiency at both ...
    • Analysis of acoustic impedance matching in dual-band ultrasound transducers 

      Myhre, Ola Finneng; Johansen, Tonni Franke; Angelsen, Bjørn Atle J. (Journal article; Peer reviewed, 2017)
      Dual-frequency band probes are needed for ultrasound (US) reverberation suppression and are useful for image-guided US therapy. A challenge is to design transducer stacks that achieve high bandwidth and efficiency at both ...
    • Auralization using headphones 

      Eide, Ingebjørg Nordstoga (Master thesis, 2012)
      In this report various techniques used to estimate head related impulse responses are compared. The purpose is to investigate the effectiveness of presenting auralization via the QuietPro system's earplugs, and see if sound ...
    • Characterization of medical piezoelectric ultrasound transducers using pulse echo methods. 

      Mylvaganam, Janani (Master thesis, 2007)
      In this thesis, a measurement set-up has been developed to characterize high frequency medical ultrasound transducers using a pulse echo set-up. This work is a continuation of an earlier project. The aim of this project ...
    • Demping av maskinstøy for mikrofon montert på utsiden av kjøretøy 

      Mølmshaug, Torstein (Master thesis, 2012)
      Målinger, analyse og filtrering av maskinstøy fra et militært kjøretøy, der hovedfokuset i oppgaven er å skape best mulige forhold for forståelse av tale.
    • Design, Fabrication and Testing Highly Sensitive Single Element Doppler Transducers 

      Bolstad, Per Kristian; Hoff, Lars; Torp, Hans; Johansen, Tonni Franke (Journal article; Peer reviewed, 2018)
      Three common piezoelectric materials have been studied for use in pulsed wave Doppler ultrasound, where high sensitivity is required, while bandwidth is less important. A large transducer aperture, 80 mm 2 , results in a ...
    • Directive under-water transducer design for Doppler velocity log 

      Tesaker, Andreas (Master thesis, 2019)
      En 1 MHz direktiv undervannstransduser for bruk i DVL er designet, simulert, konstruert og testet gjennom målinger i denne oppgaven. Designet følger teorien for en piezoelektrisk disk som opererer i tykkelsesmodi, omsluttet ...
    • Finite Element Modeling of Piezoelectric Ultrasonic Transducers 

      Nygren, Morten Wollert (Master thesis, 2011)
      The optimization of piezoelectric ultrasonic transducers has tradisionally been done through trial and error, somewhat guided by one-dimentional simulations. This can often be a very time-consuming and expensive process, ...
    • Laboratory experiments on ultrasonic logging through casing for barrier integrity validation 

      Talberg, Andreas Sørbrøden; Johansen, Tonni Franke; Larsen, Idar (Chapter, 2017)
      Verification of annular barriers is essential for well integrity, with ultrasonic methods being central in well integrity testing for many decades. By doing ultrasonic pitch-catch measurements on a bench top laboratory ...
    • Ultrasonic focusing through a steel layer for acoustic imaging 

      Talberg, Andreas Sørbrøden; Dong, Hefeng; Johansen, Tonni Franke; Måsøy, Svein-Erik; Brekke, Svein; Rommetveit, Tarjei (Journal article; Peer reviewed, 2018)
      Ultrasonic tools are being used for imaging in a large variety of fields, spanning from medical applications in a hospital to applications deep down in oil and gas wells. When applying ultrasonic imaging techniques to image ...
    • Ultrasonic Imaging through Solids 

      Samuelsen, Elly (Master thesis, 2016)
      Ultrasonic testing is a widely used method, in the industry, for non destructive inspection of materials. The most commonly used technique is the pulse-echo technique where ultrasound is introduced into a test object and ...