Browsing NTNU Open by Author "Hjelme, Dag Roar"
Now showing items 1-20 of 43
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A miniaturized ball-lensed fiber optic NIR transmission spectroscopy-based glucose sensor
Fuglerud, Silje Skeide; Milenko, Karolina Barbara; Larsen Jernelv, Ine; Ellingsen, Reinold; Aksnes, Astrid; Hjelme, Dag Roar (Chapter, 2018)A novel ball-lensed fiber transmission sensor is presented aimed at in vivo continuous glucose monitoring of diabetics. Preliminary results yield 20 mM RMSE, limited by mechanical instability. The design enables flexibility ... -
A Review of Optical Methods for Continuous Glucose Monitoring
Jernelv, Ine Larsen; Milenko, Karolina Barbara; Fuglerud, Silje Skeide; Hjelme, Dag Roar; Ellingsen, Reinold; Aksnes, Astrid (Journal article; Peer reviewed, 2018)Frequent glucose monitoring is a fundamental part of diabetes management, and good glucose control is important for long-term health outcomes. New types of electrochemical sensors that allow for continuous glucose monitoring ... -
A Review of the Role of Critical Parameters in the Design and Operation of Biogas Production Plants
Sarker, Shiplu; Lamb, Jacob Joseph; Hjelme, Dag Roar; Lien, Kristian Myklebust (Journal article; Peer reviewed, 2019)Many operating parameters, individually or together, may influence the performance of anaerobic digestion towards biogas or digestate yield and quality maximization. The most preferred method of optimizing an anaerobic ... -
A Single Point, Multi-Parameter, Fiber Optic Sensor Based on a Combination of Interferometry and LSPR
Muri, Harald Ian; Bano, Andon; Hjelme, Dag Roar (Journal article; Peer reviewed, 2018)We demonstrate a new single point, multi-parameter, fiber optic sensor concept based on a combination of interferometric and plasmonic sensor modalities on an optical fiber end face. The sensor consists of an extrinsic ... -
Addressing Challenges in Fabricating Reflection-2 Based Fiber Optic Interferometers
Wahl, Markus Solberg; Wilhelmsen, Øivind; Hjelme, Dag Roar (Journal article; Peer reviewed, 2019)abrication of multimode fiber optic interferometers requires accurate control of certain parameters to obtain reproducible results. This paper evaluates the consequences of practical challenges in fabricating reflection-based, ... -
Blood Glucose Control Using a Novel Continuous Blood Glucose Monitor and Repetitive Intravenous Insulin Boluses: Exploiting Natural Insulin Pulsatility as a Principle for a Future Artificial Pancreas
Skjaervold, Nils Kristian; Østling, Dan; Hjelme, Dag Roar; Spigset, Olav; Lyng, Oddveig; Aadahl, Petter (Journal article; Peer reviewed, 2013)The aim of this study was to construct a glucose regulatory algorithm by employing the natural pulsatile pattern of insulin secretion and the oscillatory pattern of resting blood glucose levels and further to regulate the ... -
Carbohydrate Yield and Biomethane Potential from Enzymatically Hydrolysed Saccharina latissima and Its Industrial Potential
Lamb, Jacob Joseph; Hjelme, Dag Roar; Lien, Kristian Myklebust (Journal article; Peer reviewed, 2019)The demand for fuel for utilisation of machinery and transport has culminated in large amounts of fossil fuel usage in the last century. The environmental dangers attached with the usage of fossil fuels have created a large ... -
Combined temperature and RI sensor for exploring the phase transitions of ethanol solutions
Wahl, Markus Solberg; Wilhelmsen, Øivind; Hjelme, Dag Roar (Chapter, 2018)A fiber optic interferometer based on core diameter mismatch is used in reflection mode to study the behavior of ethanol solutions with regards to concentration dependent thermal properties and phase transitions. A method ... -
Digitalization of colourimetric sensor arrays for volatile fatty acid detection in anaerobic digestion
Lamb, Jacob Joseph; Lien, Kristian Myklebust; Hjelme, Dag Roar (Journal article; Peer reviewed, 2019)During the process of converting the organic matter into methane, many volatile fatty acids (VFAs) are produced during acidogenesis and acetogenesis phases of the process. The main VFAs of interest are acetic acid, butyric ... -
Dual parameter fiber optic sensor combining a Fabry-Perot and a Mach-Zehnder interferometer
Hammarling, Krister; Wahl, Markus Solberg; Muri, Harald Ian; Engholm, Magnus; Hjelme, Dag Roar (Journal article, 2017)A new concept for dual parameter fiber optic sensor has been developed and characterized, both in a two-fiber and single-fiber configuration. The liquid sensor measures ethanol concentration with a stimuli responsive ... -
Effect of power ultrasound and Fenton reagents on the biomethane potential from steam-exploded birchwood
Lamb, Jacob Joseph; Islam, Md Hujjatul; Hjelme, Dag Roar; Pollet, Bruno; Lien, Kristian Myklebust (Journal article; Peer reviewed, 2019)The global demand for non-fossil energy sources is increasing rapidly. As a result, biogas presents a suitable alternative; however, first generation biofuels (e.g., sugar cane) potentially impact food crops globally. ... -
Effect of sensor location on continuous intraperitoneal glucose sensing in an animal model
Åm, Marte Kierulf; Kölle, Konstanze; Fougner, Anders Lyngvi; Dirnena-Fusini, Ilze; Bösch, Patrick Christian; Ellingsen, Reinold; Hjelme, Dag Roar; Stavdahl, Øyvind; Carlsen, Sven Magnus; Christiansen, Sverre (Journal article; Peer reviewed, 2018)In diabetes research, the development of the artificial pancreas has been a major topic since continuous glucose monitoring became available in the early 2000’s. A prerequisite for an artificial pancreas is fast and reliable ... -
Feasibility of supercontinuum sources for use in glucose sensing by absorption spectroscopy
Fuglerud, Silje Skeide; Milenko, Karolina Barbara; Ellingsen, Reinold; Aksnes, Astrid; Hjelme, Dag Roar (Journal article; Peer reviewed, 2019)Diabetes mellitus 1 requires tight control of the blood glucose levels to avoid harmful effects of either too high (hyperglycemia) or too low (hypoglycemia) blood sugar. Due to the availability of low-cost components, ... -
First step towards an interferometric and localized surface plasmon fiber optic sensor
Muri, Harald Ian; Bano, Andon; Hjelme, Dag Roar (Journal article; Peer reviewed, 2017)We present a first demonstration of a novel multi-parameter fiber optic (FO) sensor concept based on gold nanoparticles (GNP) embedded in a stimuli-responsive hydrogel material. A hemispherical hydrogel immobilized on the ... -
Generation, and nonlinear Parameter Estimation, of Reflection Spectra from an Intravascular Fabry-Perót Sensor, for detecting Temperature and Glucose Concentrations
Rokkones, Didrik (Master thesis, 2017)GlucoSet AS has developed an intravascular Fabry-Perót (FP) glucose sensor. The sensor consists of a hydrogel cast on an optical fiber cut, representing a low finesse FP cavity. The cavity changes length with respect to ... -
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 ... -
Ice formation and growth in supercooled water–alcohol mixtures: Theory and experiments with dual fiber sensors
Wahl, Markus Solberg; Aasen, Ailo; Hjelme, Dag Roar; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2020)Increased knowledge on fluid-solid phase transitions is needed, both when they are undesired and can impair processes operation, and when strict control is required in fields such as food technology, the pharmaceutical ... -
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 ... -
Interferometric and localized surface plasmon based fiber optic sensor
Muri, Harald Ian Di; Bano, Andon; Hjelme, Dag Roar (Journal article; Peer reviewed, 2017)We demonstrate a novel single point, multi-parameter, fiber optic sensor concept based on a combination of interferometric and plasmonic sensor modalities on an optical fiber end face. The sensor consists of a microFabry-Perot ...