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| 2. |
- Ahmadi, Omid, et al.
(författare)
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Revealing the deeper structure of the end-glacial Pärvie fault system in northern Sweden by seismic reflection profiling
- 2015
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Ingår i: Solid Earth Discussions. - : Copernicus GmbH. - 1869-9537 .- 1869-9529 .- 1869-9510. ; 6:2, s. 537-563
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Tidskriftsartikel (refereegranskat)abstract
- Fault scarps that extend up to 155 km and have offsets of tens of meters at the surface are present in the northern parts of Finland, Norway and Sweden. These fault scarps are inferred to have formed during earthquakes with magnitudes up to 8 at the time of the last deglaciation. The Pärvie fault system represents the largest earthquake so far documented in northern Scandinavia, both in terms of its length and its calculated magnitude. It is also the longest known glacially induced fault in the world. Present-day microearthquakes occur along the length of the fault scarp on the eastern side of the scarp, in general agreement with an east dipping main fault. In the central section of the fault, where there is a number of subsidiary faults east of the main fault, it has been unclear how the earthquakes relate to the faults mapped at the surface. A seismic profile across the Pärvie Fault system acquired in 2007, with a mechanical hammer as a source, showed a good correlation between the surface mapped faults and moderate to steeply dipping reflectors. The most pronounced reflector could be mapped to about 3 km depth. In an attempt to map the fault system to deeper levels, a new 22 km long 2-D seismic profile which followed the 2007 line was acquired in June 2014. For deeper penetration an explosive source with a maximum charge size of 8.34 kg in 20 m deep shot holes was used. Reflectors can now be traced to deeper levels with the main 65◦ east dipping fault interpreted as a weakly reflective structure. As in the previous profile, there is a pronounced strongly reflective 60◦ west dipping structure present to the east of the main fault that can now be mapped to about 8 km depth. Extrapolations of the main and subsidiary faults converge at a depth of about 11.5 km where current earthquake activity is concentrated, suggesting their intersection has created favorable conditions for seismic stress release. Based on the present and previous seismic reflection data, potential locations for future boreholes for drilling into the fault system are proposed.
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| 3. |
- Alakangas, Lena, et al.
(författare)
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Norrbottens malm- och mineralresurs och dess potentiella betydelse för innovation, samhälle och miljö
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Gruvindustrins betydelse för samhällsutveckling och infrastruktur i Sverige och inte minst i Norrbottens län är mycket stor. De geologiska förutsättningarna att hitta nya brytvärda förekomster i Norrbotten är goda. Länet är tillsammans med Västerbotten en av Europas viktigaste regioner för utvinning av metaller. Det syns också i den nyligen framtagna regionala mineralstrategin för Norrbotten och Västerbotten. Visionen för den regionala mineralstrategin: ”Genom långsiktigt hållbart nyttjande av Norrbottens och Västerbottens läns mineralresurser har ytterligare tillväxt skapats i regionen och hela Sverige. Vi har utvecklat och stärkt vår ställning som ledande gruv- och mineralnation.”Eftersom framtidspotentialen för gruvnäringen är mycket god men okunnigheten hos både allmänhet och beslutsfattare om näringens betydelse för innovation och samhällsutveckling är stor, kopplat med en utbredd oro för miljöpåverkan, måste dessa viktiga framtidsfrågor belysas. Med finansiering från Länsstyrelsen i Norrbotten bedrevs därför under första hälften av 2014 en förstudie som syftade till att sammanfatta kunskapsläget om framtidens gruvindustri i Norrbotten. Resultaten av förstudien redovisas i den här rapporten. En viktig slutsats är att det under nästa strukturfondsperiod (med start 2015) behövs ett framtidsinriktat forskningsprogram för att belysa de möjligheter som finns. Denna förstudie utgör grund för en kommande ansökan till strukturfonderna. Kompetensen som finns vid Luleå tekniska universitet, Sveriges centrum för gruvrelaterad forskning och utbildning, bör användas för att studera troliga framtidsmöjligheter och hur de ska kunna användas för att få en så positiv utveckling som möjligt för länet. Projektet bör innehålla följande tre huvudinriktningar, som naturligtvis hör ihop:Vilka malm- och mineralresurser finns det potential för i Norrbotten, och vilka kommer sannolikt att exploateras i framtiden?Vad kommer den exploateringen att ha för betydelse för innovation och samhällsutveckling?Vad kommer den exploateringen att få för miljöeffekter och hur ska man göra för att minska miljöbelastningen?En annan slutsats är att nedlagda gruvområden inte måste ses som förstörd natur. Betydande mervärden som gruvturism skulle kunna skapas om vilja, kreativitet och beslutsamhet finns. Detta är ett givet utvecklingsområde där småföretag och entreprenörer kan göra stor insats om de politiska och myndighetsmässiga förutsättningarna finns. Dessa aspekter skulle också kunna belysas i det föreslagna forskningsprogrammet eller i ett eget projekt.
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| 4. |
- Alhalaweh, Amjad, et al.
(författare)
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Solubility behavior and solution chemistry of indomethacin cocrystals in organic solvents
- 2011
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Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 11:9, s. 3923-3929
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Tidskriftsartikel (refereegranskat)abstract
- The main objective of this study was to investigate the solubility behavior and solution chemistry of indomethacin-saccharin (IND-SAC) cocrystals in organic media. We also evaluated previously proposed models of cocrystal solubility in organic solvents. In addition, the solubility behavior of IND-SAC cocrystals was compared with that of indomethacin-nicotinamide (IND-NIC) cocrystals using the eutectic constant approach. Phase solubility diagrams of IND-SAC cocrystals in various solvents were generated and the transition concentrations, at which drug and cocrystals are in equilibrium with the solvents, were determined. The solubility of IND-SAC cocrystals was explained by the solubility product and solution complexation. The tested models were found to fit the experimental data and to adequately explain the solubility behavior of the cocrystals. The solution complexation of IND and SAC is negligible in ethyl acetate and low in methanol and ethanol. The IND-NIC cocrystals were more soluble than the IND-SAC cocrystals in all the solvents studied. The eutectic constants predicted both the solubility and the stability of the cocrystals. Understanding the solubility behavior and solution chemistry of cocrystals has important implications for the screening, scale-up, and formulation development of this solid form. Further, the determination of eutectic constants is a simple and resource sparing means of obtaining key information on cocrystal stability and solution behavior
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| 5. |
- Alzghoul, Ahmad, et al.
(författare)
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Comparing a knowledge-based and a data-driven method in querying data streams for system fault detection: A hydraulic drive system application
- 2014
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Ingår i: Computers in industry (Print). - : Elsevier BV. - 0166-3615 .- 1872-6194. ; 65:8, s. 1126-1135
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Tidskriftsartikel (refereegranskat)abstract
- The field of fault detection and diagnosis has been the subject of considerable interest in industry. Fault detection may increase the availability of products, thereby improving their quality. Fault detection and diagnosis methods can be classified in three categories: data-driven, analytically based, and knowledge-based methods. In this work, we investigated the ability and the performance of applying two fault detection methods to query data streams produced from hydraulic drive systems. A knowledge-based method was compared to a data-driven method. A fault detection system based on a data stream management system (DSMS) was developed in order to test and compare the two methods using data from real hydraulic drive systems. The knowledge-based method was based on causal models (fault trees), and principal component analysis (PCA) was used to build the data-driven model. The performance of the methods in terms of accuracy and speed, was examined using normal and physically simulated fault data. The results show that both methods generate queries fast enough to query the data streams online, with a similar level of fault detection accuracy. The industrial applications of both methods include monitoring of individual industrial mechanical systems as well as fleets of such systems. One can conclude that both methods may be used to increase industrial system availability
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| 6. |
- Amuakwa-Mensah, Franklin, et al.
(författare)
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Re-examining the Determinants of Non-Performing Loans in Ghana’s Banking Industry: Role of the 2007–2009 Financial Crisis
- 2017
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Ingår i: Journal of African Business. - : Routledge. - 1522-8916 .- 1522-9076. ; 18:3, s. 357-379
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Tidskriftsartikel (refereegranskat)abstract
- This paper uses robust econometric methods to estimate the determinants of non-performing loans (NPLs) with a specific focus on the role of the 2007–2009 financial crisis in explaining NPLs in the banking industry of Ghana. Findings suggest that non-performing loans are significantly affected by bank-specific, industry, and macroeconomic variables. We observed heterogeneity in the determinants of NPLs for sub-samples of the data. The effect of the financial crisis on NPLs is observed to be conditional on the level of credit risk in our sub-sample analysis. The results from the impulse response corroborate that of the regression estimation.
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| 7. |
- Andersson, Magnus, et al.
(författare)
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Carbonatite ring-complexes explained by caldera-style volcanism
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Carbonatites are rare, carbonate-rich magmatic rocks that make up a minute portion of the crust only, yet they are of great relevance for our understanding of crustal and mantle processes. Although they occur in all continents and from Archaean to present, the deeper plumbing system of carbonatite ring-complexes is usually poorly constrained. Here, we show that carbonatite ring-complexes can be explained by caldera-style volcanism. Our geophysical investigation of the Alnö carbonatite ring-complex in central Sweden identifies a solidified saucer-shaped magma chamber at ∼3 km depth that links to surface exposures through a ring fault system. Caldera subsidence during final stages of activity caused carbonatite eruptions north of the main complex, providing the crucial element to connect plutonic and eruptive features of carbonatite magmatism. The way carbonatite magmas are stored, transported and erupt at the surface is thus comparable to known emplacement styles from silicic calderas.
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| 8. |
- Andersson, Mikael, et al.
(författare)
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Physical activity and fatigue in chronic obstructive pulmonary disease - A population based study
- 2015
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Ingår i: Respiratory Medicine. - : Elsevier BV. - 0954-6111 .- 1532-3064. ; 109:8, s. 1048-1057
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Tidskriftsartikel (refereegranskat)abstract
- Background: In subjects with chronic obstructive pulmonary disease (COPD), symptoms of fatigue, concomitant heart disease and low physical activity levels are more frequently described than in subjects without COPD. However, there are no population-based studies addressing the relationship between physical activity, fatigue and heart disease in COPD. The aim was to compare physical activity levels among subjects with and without COPD in a population based study, and to evaluate if concomitant heart disease and fatigue was associated to physical activity. Methods: In this, 470 subjects with COPD and 659 subjects without COPD (non-COPD) participated in examinations including structured interview and spirometry. A ratio of the forced expiratory volume in one second (FEV1)/best of forced vital capacity (FVC) and vital capacity (VC) <0.7 was used to define COPD. Physical activity was assessed with the International Physical Activity Questionnaire (IPAQ), and fatigue with the Functional Assessment of Chronic Illness Therapy - Fatigue scale (FACIT-F). Results: The prevalence of low physical activity was higher among subjects with FEV1 <80% predicted compared to non-COPD subjects (22.4% vs. 14.6%, p = 0.041). The factors most strongly associated with low physical activity in subjects with COPD were older age, OR 1.52, (95% CI 1.12-2.06), a history of heart disease, OR 2.11 (1.10-4.08), and clinically significant fatigue, OR 2.33 (1.31-4.13); while obesity was the only significant factor among non-COPD subjects, OR 2.26 (1.17-4.35). Conclusion: Physical activity levels are reduced when lung function is decreased below 80% of predicted, and the factors associated with low physical activity are different among subject with and without COPD. We propose that the presence of fatigue and heart disease are useful to evaluate when identifying subjects for pulmonary rehabilitation.
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| 9. |
- Antila, Liisa J., et al.
(författare)
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Dynamics and Photochemical H-2 Evolution of Dye-NiO Photocathodes with a Biomimetic FeFe-Catalyst
- 2016
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 1:6, s. 1106-1111
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Tidskriftsartikel (refereegranskat)abstract
- Mesoporous NiO films were cosensitized with a coumarin 343 dye and a proton reduction catalyst of the [Fe-2(CO)(6)(bdt)] (bdt = benzene-1,2-dithiolate) family. Femtosecond ultraviolet visible transient absorption experiments directly demonstrated subpicosecond hole injection into NiO from excited dyes followed by rapid (t(50%) similar to 6 ps) reduction of the catalyst on the surface with similar to 70% yield. The reduced catalyst was long-lived (2 mu s to 20 ms), which may allow protonation and a second reduction step of the catalyst to occur. A photo electrochemical device based on this photocathode produced H-2 with a Faradaic efficiency of similar to 50%. Fourier transform infrared spectroscopy and gas chromatography experiments demonstrated that the observed device deterioration with time was mainly due to catalyst degradation and desorption from the NiO surface. The insights gained from these mechanistic studies, regarding development of dye-catalyst cosensitized photocathodes, are discussed.
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| 10. |
- Arhammar, C., et al.
(författare)
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A theoretical study of possible point defects incorporated into alpha-alumina deposited by chemical vapor deposition
- 2013
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Ingår i: Theoretical Chemistry accounts. - : Springer Science and Business Media LLC. - 1432-881X .- 1432-2234. ; 133:2, s. 1433-
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Tidskriftsartikel (refereegranskat)abstract
- The energetics and electronic structure of carbon, chlorine, hydrogen, and sulfur in alpha-Al2O3 was investigated by first principles and thermodynamical calculations. These species are present in the gas phase during the synthesis of alpha-Al2O3 by chemical vapor deposition (CVD) but little is known of their solubility in this compound. The heat of formation from standard reference states of the elements varying the chemical potential of each element was calculated. An attempt to model the actual conditions in the CVD process was made, using the species and solid compounds present in a common CVD process as reference states. Our calculations suggest that sulfur from the catalyzing agent H2S will not solve in alpha-Al2O3 during deposition by CVD. It is found that the neutral chlorine and hydrogen interstitial defects display the lowest heat of formation, 281 and 280 kJ/mol, respectively, at the modeled CVD conditions. This energy is too high in order for neutral defects to form during CVD of alpha-Al2O3 at any significant amounts. The charged defects and their compensation were studied. Carbon substituting oxygen is found to be energetically favored under the modeled CVD conditions, considering carbon dioxide as competing species to solid solubility in alpha-Al2O3 at an energy of -128 kJ/mol. However, care needs to be taken when choosing the possible competing carbon-containing phases. Compensation of carbon substituting for oxygen by oxygen vacancies takes place at 110 kJ/mol from standard reference states, graphite, fcc-Al and O-2. The carbon solubility in Al2O3 is difficult to measure with standard analysis techniques such as X-ray diffraction and energy dispersive X-ray spectroscopy, but several stable compounds in the Al-C-O are available in the literature.
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