Fakultet for naturvitenskap og teknologi: Recent submissions
Now showing items 3181-3200 of 5336
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Direct Measurement of the Magnitude of the van der Waals Interaction of Single and Multilayer Graphene
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-23)Vertical stacking of monolayers via van der Waals (vdW) assembly is an emerging field that opens promising routes toward engineering physical properties of two-dimensional materials. Industrial exploitation of these engineering heterostructures as robust functional materials still requires bounding their measured properties so as to enhance theoretical tractability and assist in experimental designs. ... -
Multivariate analysis of Co, Fe and Ni leaching from tailings following simulated temperature change
(Journal article; Peer reviewed, 2018)A series of column leaching experiments were performed to understand the leaching behavior of Co, Fe and Ni in Ballangen mine tailings. Multivariate statistical approaches to evaluate potential risk variations in leachate quality and identifies temperature effects on their leaching behavior. Results from column leaching test indicated that the mobility of showed higher temperature may encourage ... -
Innføring av studentaktive arbeidsformer i seminarundervisningen. Hvilken betydning har dette på læringsutbyttet og klassemiljøet?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-08)I denne studien ønsket vi å undersøke hvordan innføring av studentaktive læringsformer i seminarundervisningen påvirket det faglige læringsutbyttet og klassemiljøet i STEM-fag (science, technology, engineering and mathematics). Et randomisert kontrollert studie ble gjennomført i seminarundervisningen i to innføringsemner i fysikk og kjemi ved UiT Norges arktiske universitet. I emnene fulgte ... -
Quantification of the magnitude of net apparent erosion in the southwestern Barents Sea by using compaction trends in shales and sandstones – Implications for hydrocarbon exploration
(Doctoral thesis; Doktorgradsavhandling, 2019-03-28)On the Norwegian Continental Shelf, the western Barents Sea shelf is generally ice-free and proven by recent discoveries as a frontier area for hydrocarbon exploration. During the Cenozoic, most of the areas of the Barents Sea were subjected to significant uplift and erosion, processes that have had important consequences on the petroleum systems.<p> <p>This thesis aimed to investigate the ... -
Model-Based Polarimetric Decomposition With Higher Order Statistics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-11)This letter presents a new general framework for solving polarimetric target decompositions that extends them to use more statistical information and include radar texture models. Polarimetric target decomposition methods generally have more physical parameters than equations and are, thus, underdetermined and have no unique solution. The common approach to solve them is to make certain assumptions, ... -
Estimating solar irradiation in the Arctic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-08-22)Solar radiation data plays an important role in pre-feasibility studies of solar electricity and/or thermal system installations. Measured solar radiation data is scarcely available due to the high cost of installing and maintaining high quality solar radiation sensors (pyranometers). Indirect measured radiation data received from geostationary satellites is unreliable at latitudes above 60 degrees ... -
Solar resource assessment at high latitude regions
(Doctoral thesis; Doktorgradsavhandling, 2019-03-22)There has been a growing interest in accurately estimating surface solar radiation at high latitude locations. From a Scandinavian perspective, the installed solar photovoltaic share is increasing, primarily because of the declining cost of these systems, the introduction of various economic incentives and societal push to generate one’s own clean power. In the coming years, it is anticipated that ... -
Monitoring of Marine Ice and its Thickness for Ship Anti-/De-icing - Experimental and Analytical Study using Infrared Thermography
(Doctoral thesis; Doktorgradsavhandling, 2019-03-01)Ships operating in a cold climate face many challenges. There are several associated risks such as safety concerns, down time, energy consumption and limited resources. Amongst the key challenges, ship ice accretion is significant for cold climate operations. Exposing superstructures to the marine icing phenomenon can affect the ship’s operations, risking the safety of humans and machines. In this ... -
The nonlinear nature of biology
(Doctoral thesis; Doktorgradsavhandling, 2019-03-27)In this thesis, we explore the stability and the breakdown of stability of biological systems. The main examples are the blood system and invasion of cancer. However, the models presented in the thesis apply to several other examples. Biological systems are characterised by both competition and cooperation. Cooperation is based on an unsolvable dilemma: Even though mutual cooperation leads to ... -
ConnNet: A Long-Range Relation-Aware Pixel-Connectivity Network for Salient Segmentation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-14)Salient segmentation aims to segment out attention-grabbing regions, a critical yet challenging task and the foundation of many high-level computer vision applications. It requires semantic-aware grouping of pixels into salient regions and benefits from the utilization of global multi-scale contexts to achieve good local reasoning. Previous works often address it as two-class segmentation problems ... -
The EOS Formulation for Linear and Nonlinear Transient Scattering Problems
(Doctoral thesis; Doktorgradsavhandling, 2019-03-29)This thesis developed the EOS formulations of solving nonlinear transient scatterings, both for 1D case and 3D Maxwell's equations. This method can be accurately and stably implemented using one particular choice of numerical scheme for the inside of the objects and for the required integral representations of the boundary values. For a stable numerical solution, the time step needs to be confined ... -
Energy conversion in cometary atmospheres - Hybrid modeling of 67P/Churyumov-Gerasimenko
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-21)<i>Aims</i>: We wish to investigate the energy conversion between particles and electromagnetic fields and determine the location where it occurs in the plasma environment of comets.<p> <p><i>Methods</i>: We used a hybrid plasma model that included photoionization, and we considered two cases of the solar extreme ultraviolet flux. Other parameters corresponded to the conditions of comet ... -
Incorporating Incidence Angle Variation into Sar Image Segmentation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-05)We present a new approach for incorporating incidence angle derived synthetic aperture radar (SAR) brightness variation directly into SAR image analysis. This approach is unique in that the incidence angle dependency is modeled explicitly into the probability density function rather than an image-wide pre-processing `correction'. It can then be used for supervised and unsupervised image analysis, ... -
The effect of temperature and precipitation on the leaching of contaminants from Ballangen tailings deposit, Norway
(Journal article; Peer reviewed, 2019)Leaching and transport of contaminants from tailings deposit is a highly complex interacting system affected by a suite of environmental factors, among which temperature and precipitation rates linked to climate change are two important parameters. The climate change in the Nordic region is more drastic than other regions. In this study, a laboratory batch leaching experiment was performed on the ... -
On the causes of Arctic sea ice in the warm Early Pliocene
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-30)Scattered and indirect evidence suggests that sea ice occurred as far south as the Iceland Sea during the Early Pliocene, when the global climate was warmer than present. However, conclusive evidence as well as potential mechanisms governing sea ice occurrence outside the Arctic Ocean during a time with elevated greenhouse gas concentrations are still elusive. Here we present a suite of organic ... -
Ranking Using Transition Probabilities Learned from Multi-Attribute Data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-13)In this paper, as a novel approach, we learn Markov chain transition probabilities for ranking of multi-attribute data from the inherent structures in the data itself. The procedure is inspired by consensus clustering and exploits a suitable form of the PageRank algorithm. This is very much in the spirit of the original PageRank utilizing the hyperlink structure to learn such probabilities. ... -
Climate variability in the subarctic area for the last 2 millennia
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-25)To put recent climate change in perspective, it is necessary to extend the instrumental climate records with proxy data from paleoclimate archives. Arctic climate variability for the last 2 millennia has been investigated using statistical and signal analyses from three regionally averaged records from the North Atlantic, Siberia and Alaska based on many types of proxy data archived in the ... -
Low-frequency radio absorption in Cassiopeia A
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-08)<i>Context</i>: Cassiopeia A is one of the best-studied supernova remnants. Its bright radio and X-ray emission is due to shocked ejecta. Cas A is rather unique in that the unshocked ejecta can also be studied: through emission in the infrared, the radio-active decay of <sup>44</sup>Ti, and the low-frequency free-free absorption caused by cold ionised gas, which is the topic of this paper.<p> ... -
Genome mapping of seed-borne allergens and immunoresponsive proteins in wheat
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-17)Wheat is an important staple grain for humankind globally because of its end-use quality and nutritional properties and its adaptability to diverse climates. For a small proportion of the population, specific wheat proteins can trigger adverse immune responses and clinical manifestations such as celiac disease, wheat allergy, baker’s asthma, and wheat-dependent exercise-induced anaphylaxis (WDEIA). ... -
Way-finding on-board training for maritime vessels
(Journal article; Peer reviewed, 2018-01-03)In the maritime industry, it is of vital importance that personnel onboard ships are familiarized with the ship’s layout, along with safety equipment and processes for safeguarding of the individual seafarer and the ship’s crew. In fact, international maritime regulations require that all personnel employed or engaged on a seagoing ship receive proper familiarization training. However, several studies ...