Fakultet for naturvitenskap og teknologi: Recent submissions
Now showing items 161-180 of 4889
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Investigation and analysis of the ‘cold’ sensation relation with respect to associated parameters: wind velocity, ambient temperature, humidity, and irradiance
(Master thesis; Mastergradsoppgave, 2019-07-15)The Arctic is considered as one of the regions in the world with various resources including oil and gas. Many industries are moving further up north to this area or new industries are being established. Technologies and industries in the Arctic have many challenges regarding the harsh cold climate. One of the main challenges which is of importance in this thesis is human exposure to the cold that ... -
Assessing resilience in mechanical systems: an industrial perspective
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-12)Purpose - Resilience as a novel concept has attracted the most attention in the management of engineering systems. The main goal of engineering systems is production assurance and increasing customer satisfaction which depends on the suitable performance of mechanical equipment. “A resilient system is defined as a system that is resistant to disruption and failures and can recover itself and returns ... -
Correlation between Wettability and Dissolution of Calcite in Ion-Free Water
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-13)Calcite, a prevalent mineral in the earth’s crust, plays a pivotal role in various geological and industrial processes, including carbon sequestration, water treatment, and enhanced oil recovery. Understanding how wettability (a crucial surface property influenced by the interaction between calcite and surrounding fluids) affects calcite’s dissolution is essential for optimizing these processes. We ... -
Tracing Subducted Carbonates in Earth's Mantle Using Zinc and Molybdenum Isotopes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-23)Although carbonates are the primary form of carbon subducted into the mantle, their fate during recycling is debated. Here we report the first coupled high-precision Zn and Mo isotope data for Cenozoic intraplate basalts from western China. The exceptionally high δ<sup>66</sup>Zn values (+0.39 to +0.50‰) of these lavas require involvement of recycled carbonates in the mantle source. Variable ... -
Efficient palladium-catalyzed electrocarboxylation enables late-stage carbon isotope labelling
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-22)Carbon isotope labelling of bioactive molecules is essential for accessing the pharmacokinetic and pharmacodynamic properties of new drug entities. Aryl carboxylic acids represent an important class of structural motifs ubiquitous in pharmaceutically active molecules and are ideal targets for the installation of a radioactive tag employing isotopically labelled CO<sub>2</sub>. However, direct isotope ... -
Adsorption free energy of phenol onto coronene: Solvent and temperature effects
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-11)Molecular modeling can considerably speed up the discovery of materials with high adsorption capacity for wastewater treatment. Despite considerable efforts in computational studies, the molecular modeling of adsorption processes has several limitations in reproducing experimental conditions. Handling the environmental effects (solvent effects) and the temperature effects are part of the important ... -
Hydrogen bond networks of dimethylsulfoxide (DMSO) pentamer
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-17)Understanding of clusters of dimethylsulfoxide (DMSO) is important in several applications in Chemistry. Despite its importance, very few studies of DMSO clusters, (DMSO)<i><sub>n</i></sub> , have been reported in comparison to systems such as water clusters or methanol clusters. In order to provide further understanding of DMSO clusters, we investigated the structures and non-covalent interactions ... -
Unleashing the VAMPyR. A Python Journey into the Realm of Multiwavelets and Quantum Chemisty
(Doctoral thesis; Doktorgradsavhandling, 2024-04-04)This thesis presents VAMPyR, an advancement in quantum chemistry that significantly mitigates the challenges inherent in high-precision computational methods. By providing a Python interface to the multiwavelet-based functionalities of MRCPP, VAMPyR enables a more intuitive, accessible, and efficient approach to quantum chemical calculations, reducing the complexity traditionally encountered with ... -
Biogeographic gradients of picoplankton diversity indicate increasing dominance of prokaryotes in warmer Arctic fjords
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-02)limate change is opening the Arctic Ocean to increasing human impact and ecosystem changes. Arctic fjords, the region’s most productive ecosystems, are sustained by a diverse microbial community at the base of the food web. Here we show that Arctic fjords become more prokaryotic in the picoplankton (0.2–3 µm) with increasing water temperatures. Across 21 fjords, we found that Arctic fjords had ... -
Biogeochemical impact of historical submarine mine tailings on benthic ecosystems in the Repparfjord (Northern Norway)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-08)Historical copper mine tailings deposited in the Repparfjord, Northern Norway, provided new insight into the biogeochemical impact of submarine tailings disposals on high-latitude coastal ecosystems. The submarine tailings disposal in the Repparfjord represents a product of mining activities between 1972 and 1979. Their environmental impact has been extensively studied during the last decade, but ... -
On the strength of E and F region irregularities for GNSS scintillation in the dayside polar ionosphere
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-02)We present results of the study conducted to quantify the relative contribution of different ionospheric regions to phase scintillation in Global Navigation Satellite Systems (GNSS) at the dayside high latitude ionosphere. By taking advantage of the scanning capability of the 32-m EISCAT radar in Svalbard (ESR) and its recurrent favourable location below the dayside auroral region, we developed ... -
Simultaneous electrochemical determination of benzenediol compounds in environmental samples using nano architectures of hydrogen ammonium zinc molybdate layered double hydroxides integrated with carbon black modified electrode
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-02)Phenolic compounds, such as benzenediol (BD), are toxic and exhibit poor biodegradability, posing a threat to human health and the environment, even at low concentrations. Therefore, the simultaneous detection of BD at low detection limits and a wide detection range is of significant interest for monitoring water quality and environmental remediation efforts. In this study, we developed a novel ... -
Quantification of van der Waals forces in bimodal and trimodal AFM
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-22)The multifrequency formalism is generalized and exploited to quantify attractive forces, i.e., van der Waals interactions, with small amplitudes or gentle forces in bimodal and trimodal atomic force microscopy (AFM). The multifrequency force spectroscopy formalism with higher modes, including trimodal AFM, can outperform bimodal AFM for material property quantification. Bimodal AFM with the second ... -
Quasi Monte Carlo time-frequency analysis
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-30)We study signal processing tasks in which the signal is mapped via some generalized time-frequency transform to a higher dimensional time-frequency space, processed there, and synthesized to an output signal. We show how to approximate such methods using a quasi-Monte Carlo (QMC) approach. We consider cases where the time-frequency representation is redundant, having feature axes in addition to the ... -
Efficient photoelectrocatalytic degradation of amoxicillin using nano-TiO<inf>2</inf> photoanode thin films: A comparative study with photocatalytic and electrocatalytic methods
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-24)Excessive utilization of antibiotics in human, animal, and aquaculture poses a substantial threat to human health and the environment. Photoelectrochemical processes are increasingly applied for water remediation because they generate oxidizing species and mineralize organic pollutants, making even small water quantities more amenable for utilization. Thus, this study presents the fabrication of an ... -
Regiodivergent Synthesis of 11H-Indolo[3,2-c]quinolines and Neocryptolepine from a Common Starting Material
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-23)A large number of diversely functionalized analogs of the bioactive natural products neocryptolepine and isocryptolepine have been prepared from a series of 3-bromoquinoline derivatives. The neocryptolepines were obtained by a Pd<sup>0</sup>-catalyzed C−C bond coupling followed by C−N bond formation in yields up to 80 %, whereas the indoloquinolines were prepared by a Suzuki-Miyaura cross-coupling ... -
Redox state of the Dharwar craton root as inferred from eclogite and peridotite sourced mantle cargo, with implications for kimberlite and lamproite magma formation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-16)Despite over 400 occurrences of kimberlites and related rocks in India, mantle-derived xenoliths are known only from a few occurrences. This paucity of mantle-derived xenoliths in Indian kimberlites has hampered investigations of the subcontinental lithospheric mantle (SCLM). Using a valuable selection of the rare xenolith inventory, we here report Fe<sup>3+</sup>/ΣFe measurements for garnets using ... -
Photophysics of uracil: an explicit time-dependent generating function-based method combining both nonadiabatic and spin-orbit coupling effects
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-14)We present a composite framework for calculating the rates of non-radiative deactivation processes, namely internal conversion (IC) and intersystem crossing (ISC), on an equal footing by explicitly computing the non-adiabatic coupling (NAC) and spin–orbit coupling (SOC) constants, respectively. The stationary-state approach uses a time-dependent generating function based on Fermi's golden rule. We ... -
Augmented Reality enhanced device usage training tool for in-home health-self-monitoring by pregnant women
(Journal article; Tidsskriftartikkel, 2023-09)Virtual care comprising virtual visits and monitoring via audio or video has the potential to reduce access barriers to care and has been successfully implemented in prenatal care. It reduces the frequency of in-person visits and increases self-care skills. However, the knowledge and competence in handling monitoring equipment at home directly influences satisfaction and engagement with the ... -
Mabnet: Master Assistant Buddy Network With Hybrid Learning for Image Retrieval
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-05)Image retrieval has garnered a growing interest in recent times. The current approaches are either supervised or self-supervised. These methods do not exploit the benefits of hybrid learning using both supervision and self-supervision. We present a novel Master Assistant Buddy Network (MAB-Net) for image retrieval which incorporates both the learning mechanisms. MABNet consists of master and assistant ...