Blar i NTNU Open på forfatter "Aksnes, Astrid"

Viser treff 21-40 av 79

    • Glucose sensing by absorption spectroscopy using lensed optical fibers 

      Fuglerud, Silje Skeide; Milenko, Karolina Barbara; Ellingsen, Reinold; Aksnes, Astrid; Hjelme, Dag Roar (Journal article; Peer reviewed, 2019)
      The bulkiness of common transmission spectroscopy probes prevents applicability at remote locations such as within the body. We present the fabrication and characterization of lensed fibers for transmission spectroscopy ...

    • Heterodyne interferometer for absolute amplitude vibration measurements with femtometer sensitivity 

      Leirset, Erlend; Engan, Helge Emil; Aksnes, Astrid (Journal article; Peer reviewed, 2013)
      A heterodyne interferometer for highly sensitive vibration measurements in the range 100kHz − 1.3GHz is presented. The interferometer measures absolute amplitude and phase. The signal processing of the setup is analyzed ...

    • High-concentration wide-angle tracking integration with stacked lens arrays 

      Johnsen, Håkon Jarand Dugstad; Aksnes, Astrid; Torgersen, Jan (Chapter, 2019)
      Tracking-integration can reduce or eliminate the need for external solar tracking in CPV (concentrator photovoltaics). Previous research has shown how tracking-integrated systems can achieve high concentration ratios, wide ...

    • High-performance stationary solar tracking through multi-objective optimization of beam-steering lens arrays 

      Johnsen, Håkon Jarand Dugstad; Aksnes, Astrid; Torgersen, Jan (Peer reviewed; Journal article, 2020)
      Beam-steering lens arrays enable solar tracking using millimeter-scale relative translation between a set of lens arrays. This may represent a promising alternative to the mechanical bulk of conventional solar trackers, ...

    • Hyperspectral Analysis of Plastic Particles in the Ocean 

      Bogfjellmo, Silja (Master thesis, 2016)
      Huge amounts of plastics end up in the ocean each year. Some of the plastics are eaten by fish and birds, and can cause death. It is important to find an easy, fast and reliable method to detect the plastics, as a first ...

    • Hyperspectral imaging of atherosclerotic plaques in vitro 

      Larsen, Eivind La Puebla; Randeberg, Lise Lyngsnes; Olstad, Elisabeth; Haugen, Olav Anton; Aksnes, Astrid; Svaasand, Lars O. (Journal article; Peer reviewed, 2011)
      Vulnerable plaques constitute a risk for serious heart problems, and are difficult to identify using existing methods. Hyperspectral imaging combines spectral- and spatial information, providing new possibilities for precise ...

    • Impact of Silanization Parameters and Antibody Immobilization Strategy on Binding Capacity of Photonic Ring Resonators 

      Arnfinnsdottir, Nina Bjørk; Chapman, Cole A; Bailey, Ryan C; Aksnes, Astrid; Stokke, Bjørn Torger (Peer reviewed; Journal article, 2020)
      Ring resonator-based biosensors have found widespread application as the transducing principle in “lab-on-a-chip” platforms due to their sensitivity, small size and support for multiplexed sensing. Their sensitivity is, ...

    • Infrared measurements of glucose in peritoneal fluid with a tuneable quantum cascade laser 

      Jernelv, Ine Larsen; Hjelme, Dag Roar; Aksnes, Astrid (Peer reviewed; Journal article, 2020)
      Fast and accurate continuous glucose monitoring is needed in future systems for control of blood glucose levels in type 1 diabetes patients. Direct spectroscopic measurement of glucose in the peritoneal cavity is an ...

    • Infrared Spectroscopy with a Fiber-Coupled Quantum Cascade Laser for Attenuated Total Reflection Measurements Towards Biomedical Applications 

      Jernelv, Ine Larsen; Strøm, Karina; Hjelme, Dag Roar; Aksnes, Astrid (Journal article; Peer reviewed, 2019)
      The development of rapid and accurate biomedical laser spectroscopy systems in the mid-infrared has been enabled by the commercial availability of external-cavity quantum cascade lasers (EC-QCLs). EC-QCLs are a preferable ...

    • Investigation of methods for speckle contrast reduction 

      Welde, Kristine (Master thesis, 2010)
      Speckle arises when coherent light is reflected from a rough screen and observed by an intensity detector with a finite aperture. Because speckle causes serious image degradation when lasers are used as light sources in ...

    • Investigation of the effect of clinically relevant interferents on glucose monitoring using near‐infrared spectroscopy 

      Fuglerud, Silje Skeide; Ellingsen, Reinold; Aksnes, Astrid; Hjelme, Dag Roar (Peer reviewed; Journal article, 2021)
      Near infrared spectroscopy (NIR) is a promising technique for continuous blood glucose monitoring for diabetic patients. Four interferents, at physiological concentrations, were introduced to study how the glucose predictions ...

    • Measurements of Optical Penetration Depth in Smoked Salmon 

      Johansen, Remi Andre Ursin (Master thesis, 2008)
      Optical spectroscopy is a common method used in the determination of quality parameters in groceries. An optical characterization of smoked Atlantic salmon was carried out in this thesis. The optical penetration depth in ...

    • Micro-lensed negative-curvature fibre probe for raman spectroscopy 

      Milenko, Karolina Barbara; Yerolatsitis, Stephanos; Aksnes, Astrid; Hjelme, Dag Roar; Stone, James M. (Peer reviewed; Journal article, 2021)
      We developed a novel miniature micro-lensed fibre probe for Raman spectroscopy. The fibre probe consists of a single negative-curvature fibre (NCF) and a spliced, cleaved, micro-lensed fibre cap. Using a single NCF, we ...

    • Micro-lensed optical fibers for a surface-enhanced Raman scattering sensing probe 

      Milenko, Karolina Barbara; Fuglerud, Silje Skeide; Kjeldby, Snorre B; Ellingsen, Reinold; Aksnes, Astrid; Hjelme, Dag Roar (Journal article; Peer reviewed, 2018)
      We present the fabrication and characterization of a novel sensing configuration based on surface-enhanced Raman scattering (SERS) and two micro-lensed optical fibers. The first micro-lensed fiber is used to excite surface ...

    • Mid-Infrared Laser Spectroscopy for Glucose Sensing 

      Strøm, Karina (Master thesis, 2019)
      For å kunne lage en enhet for kontinuerlig glukosemåling som har lang levetid er det ønskelig med en forbedret spektroskopi målemetode for å kunne detektere glukose. En slik enhet vil kunne forbedre livskvaliteten til ...

    • Mid-infrared spectroscopy with a fiber-coupled tuneable quantum cascade laser for glucose sensing 

      Jernelv, Ine Larsen; Strøm, Karina; Hjelme, Dag Roar; Aksnes, Astrid (Peer reviewed; Journal article, 2020)
      A fiber-coupled transmission spectroscopy setup using a pulsed external-cavity quantum cascade laser (EC-QCL, 1200-900 cm−1 ) has been developed and demonstrated for measurements of aqueous solutions. The system has been ...

    • Mid-Infrared Tuneable Laser Spectroscopy for Glucose Sensing 

      Jernelv, Ine L. (Doctoral theses at NTNU;2020:231, Doctoral thesis, 2020)
      Mid-infrared spectroscopy is a versatile analytical technique, with recent technological developments that enable further advancements towards miniaturised and portable sensor applications. Quantum cascade lasers (QCLs) ...

    • Multiple gas detection systems based on tunable diode laser absorption spectroscopy 

      Seem, Anne Charlotte (Master thesis, 2007)
      Simultaneous detection of multiple gases is useful in many applications. In this thesis, the simultaneous detection of CO and O2 based on tunable diode laser absorption spectroscopy (TDLAS) with wavelength modulation ...

    • Multiplexed Mach-Zehnder interferometer assisted ring resonator sensor 

      Yadav, Mukesh; Aksnes, Astrid (Peer reviewed; Journal article, 2022)
      A Mach-Zehnder interferometer assisted ring resonator configuration (MARC)-based multiplexed photonic sensor with a large measurement range is experimentally demonstrated. The presented MARC sensor consists of a balanced ...

    • Near Infrared Spectroscopy for Continuous Glucose Monitoring 

      Schwermer, Silje Fuglerud (Doctoral theses at NTNU;2022:184, Doctoral thesis, 2022)
      Millions of people are affected by diabetes. The disease can be managed by measuring the blood glucose levels and administering appropriate insulin doses. However, diabetes management is difficult and time consuming for ...