| 1. |
- Beecken, Jörg, 1982, et al.
(författare)
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Performance assessment of state-of-the-art and novel methods for remote compliance monitoring of sulfur emissions from shipping
- 2023
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Ingår i: Atmospheric Measurement Techniques. - 1867-1381 .- 1867-8548. ; 16:23, s. 5883-5895
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Tidskriftsartikel (refereegranskat)abstract
- The fuel sulfur content (FSC) of ocean-going and inland vessels was measured simultaneously by eight different state-of-the-art and novel monitoring systems during a 6-week campaign at the Elbe River, at a distance of about 10 km to the port of Hamburg, Germany. Both stationary and airborne systems on unoccupied aerial vehicles (UAVs) were operated by four participating partners in a side-by-side measurement setup to measure the emission factors of the same emission sources. A novel laser spectrometer, with significantly better-precision specifications as compared with the other instruments, was used for the first time for emission monitoring regarding the International Convention for the Prevention of Pollution from Ships (MARPOL) Annex VI regulations. The comparison took place in the North Sea sulfur emission control area (SECA), where the allowed FSC is limited to 0.10 %Sm/m. The unit %Sm/m relates to the percentage of mass sulfur per mass combusted fuel. In total, 966 plumes that originated from 436 different vessels were analysed in this study. At the same time, fuel samples obtained from 34 different vessels and bunker delivery notes (BDNs) from five frequently monitored vessels were used as a reference to assess the uncertainties of the different systems. Seven of the eight measurement systems tended to underestimate the FSC found from fuel samples and BDNs. A possible relation between underestimation and high relative humidities (above 80 %) was observed. The lowest systematic deviations were observed for the airborne systems and the novel laser spectrometer. The two UAV-borne systems showed total uncertainties of 0.07 %Sm/m and 0.09 %Sm/m (confidence level: 95 %). The novel laser spectrometer showed the lowest total uncertainty of 0.05 %Sm/m compared with other stationary sniffer systems, whose total uncertainties range from 0.08 %Sm/m to 0.09 %Sm/m. It was concluded that non-compliant vessels, with an actual FSC of the combusted fuel above 0.15 %Sm/m to 0.19 %Sm/m, can be detected by the compared systems with 95 % confidence.
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| 2. |
- Jiang, Hui, et al.
(författare)
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Solar forcing of Holocene summer sea-surface temperatures in the northern North Atlantic
- 2015
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Ingår i: Geology. - 0091-7613. ; 43:3, s. 203-206
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Tidskriftsartikel (refereegranskat)abstract
- Mounting evidence from proxy records suggests that variations in solar activity have played a significant role in triggering past climate changes. However, the mechanisms for sun-climate links remain a topic of debate. Here we present a high-resolution summer sea-surface temperature (SST) record covering the past 9300 yr from a site located at the present-day boundary between polar and Atlantic surface-water masses. The record is age constrained via the identification of 15 independently dated tephra markers from terrestrial archives, circumventing marine reservoir age variability problems. Our results indicate a close link between solar activity and SSTs in the northern North Atlantic during the past 4000 yr; they suggest that the climate system in this area is more susceptible to the influence of solar variations during cool periods with less vigorous ocean circulation. Furthermore, the high-resolution SST record indicates that climate in the North Atlantic regions follows solar activity variations on multidecadal to centennial time scales.
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| 3. |
- Brenne, Elisabeth, et al.
(författare)
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Depressed patients with incurable cancer : which depressive symptoms do they experience?
- 2013
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Ingår i: Palliative & Supportive Care. - 1478-9515 .- 1478-9523. ; 11:6, s. 491-501
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Forskningsöversikt (refereegranskat)abstract
- OBJECTIVE: Diagnosing depressive disorders in palliative care is challenging because of the overlap between some depressive symptoms and cancer-related symptoms, such as loss of appetite and fatigue. In order to improve future assessment of depression in palliative care, depressive symptoms experienced by patients receiving pharmacological treatment for depression were assessed and compared to the American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) criteria for major depressive disorder.METHOD: Thirty Norwegian (n = 20) and Austrian (n = 10) patients with advanced cancer were included. Semistructured interviews on symptom experiences were conducted and transcribed verbatim. By the phenomenographic method, patients' symptom experiences were extracted and sorted by headings, first individually and then across patients. The patients subsequently rated 24 symptoms numerically including the DSM-IV depression criteria.RESULTS: Lowered mood and a diminished motivational drive were prominent and reflected the two main DSM-IV symptom criteria. A relentless focus on their actual situation, restlessness, disrupted sleep, feelings of worthlessness, feelings of guilt, and thoughts of death as a solution were variably experienced. Appetite and weight changes, fatigue and psychomotor retardation were indistinguishable from cancer symptoms. All these symptoms reflected DSM-IV symptom criteria. Some major symptoms occurred that are not present in the DSM-IV symptom criteria: despair, anxiety, and social withdrawal. The numerical ratings of symptoms were mainly in accordance with the findings from the qualitative analysis.SIGNIFICANCE OF RESULTS: Despair, anxiety, and social withdrawal are common symptoms in depressed patients with incurable cancer, and, therefore, hypothesized as candidate symptom criteria. Other symptom criteria might need adjustment for improvement of relevance in this group of patients.
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| 4. |
- Jonzén, Niclas, et al.
(författare)
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Response to comment on "Rapid advance of spring arrival dates in long-distance migratory birds"
- 2007
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 315:5812, s. 598-598
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Both's comment questions our suggestion that the advanced spring arrival time of long-distance migratory birds in Scandinavia and the Mediterranean may reflect a climate-driven evolutionary change. We present additional arguments to support our hypothesis but underscore the importance of additional studies involving direct tests of evolutionary change.
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| 5. |
- Knudsen, Endre, et al.
(författare)
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Characterizing bird migration phenology using data from standardized monitoring at bird observatories
- 2007
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Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 35:1-2, s. 59-77
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Forskningsöversikt (refereegranskat)abstract
- Long-term data from standardized monitoring programmes at bird observatories are becoming increasingly available. These data are frequently used for detecting changes in the timing of bird migration that may relate to recent climate change. We present an overview of problematic issues in the analysis of these data, and review approaches to and methods for characterizing bird migration phenology and its change over time. Methods are illustrated and briefly compared using autumn data on garden warbler Sylvia borin from a standardized mist-netting programme at Lista bird observatory, southern Norway. Bird migration phenology is usually characterized rather coarsely using a small number of sample statistics such as mean, median and selected quantiles. We present 2 alternative approaches. Smoothing methods describe the within-season pattern in the data at an arbitrary level of detail, while fitting a parametric seasonal distribution curve offers a coarse description of migration phenology relatively robust to sampling effects. Various methods for analyzing linear trends in the timing of bird migration are reviewed and discussed. Exploratory studies using long-term data gathered at bird observatories can yield more detailed insight into the phenomenon of bird migration and how phenologies relate to climate. Methodological advances are needed, particularly in order to better characterize the shape of phenological distributions and separate between sampling effects and 'true' phenology.
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| 6. |
- Larsen, Simon R., et al.
(författare)
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Sample cell for studying liquid interfaces with an in situ electric field using X-ray reflectivity and application to clay particles at oil–oil interfaces
- 2018
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Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 25:Part: 3, s. 915-917
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Tidskriftsartikel (refereegranskat)abstract
- Commissioning results of a liquid sample cell for X-ray reflectivity studies with an in situ applied electrical field are presented. The cell consists of a Plexiglas container with lateral Kapton windows for air-liquid and liquid-liquid interface studies, and was constructed with grooves to accept plate electrodes on the walls parallel to the direction of the beam. Both copper and ITO plate electrodes have been used, the latter being useful for simultaneous optical studies. Commissioning tests were made at the I07 beamline of the Diamond Light Source.
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| 7. |
- Mauroy, Henrik, et al.
(författare)
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Anisotropic clay–polystyrene nanocomposites: Synthesis, characterization and mechanical properties
- 2015
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Ingår i: Applied Clay Science. - : Elsevier BV. - 1872-9053 .- 0169-1317. ; 108, s. 19-27
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies on clay–polymer nanocomposites have shown prominent improvements in thermal and mechanical propertieswith the addition of quite small amounts of nanometer sized clay particles. The present work presents characterization of anisotropic clay–polystyrene nanocomposites synthesized via a guided self-assembly technique, employing electric fields to align the clay particles into chain-like structures inside the polymer matrix. Four different kinds of surface modified clay were used as particle additives, namely Hectorite, Laponite, Na-Montmorillonite and Li-Fluorohectorite. The microstructure of the nanocomposites was examined with wide angle X-ray scattering (WAXS), X-ray computed microtomography (XMT) and transmission electron microscopy (TEM). Thermogravimetric analysis (TGA) was further employed to examine the high-temperature resilience of the nanocomposites before determination of the mechanical properties during compression. The results showed that the nanocomposites were of the intercalated type with the clay dispersed as ~15–70 nm thick crystallites which in turn aggregated into micrometer sized particles. Alignment of the clay particles into chains inside the polymer matrix led to differences in mechanical properties compared to nanocomposites having a randomorientation of the clay particles. In particular the aligned polystyrene–fluorohectorite nanocomposite displayed large improvements compared to its non-aligned counterpart. It was also observed that differences in yield strength depended on the compression direction.
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| 8. |
- Mauroy, Henrik, et al.
(författare)
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Effect of Clay Surface Charge on the Emerging Properties of Polystyrene−Organoclay Nanocomposites
- 2013
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:38, s. 19656-19663
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Tidskriftsartikel (refereegranskat)abstract
- A series of polystyrene-clay nanocomposites, based on two natural clay types (Na-Montmorillonite and Hectorite) and two synthetic clays (Laponite and Li- Fluorohectorite), were prepared via in situ intercalative polymerization after surface modification with an organic ammonium cation (CTAB). The structural characteristics of the organically modified clays as well as the nanocomposites were investigated by means of wide-angle X-ray scattering (WAXS), and the thermal properties were studied with TGA. In the organically modified clays, the silicate interlayer spacing increases, and the magnitude seems to be directly correlated with the amount of clay surface charge. In the nanocomposites, polymer intercalation is also observed, but partial exfoliation is present, modifying significantly the morphology of the material. The degree of dispersion of the clay platelets, as well as the resulting properties of the nanocomposites, were found again to be systematically, and almost linearly, correlated with the intrinsic surface charge of the clays, which varied between 44 and 120 meq/100 g. Increased dispersion was seen in the nanocomposites made from clays with low surface charge, here Hectorite and Laponite, suggesting that these can be suitable alternatives to the more employed Montmorillonite for enhancement of thermal properties. The thermal stability was found to be better for the nanocomposites than for the pure polystyrene.
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| 9. |
- Mauroy, Henrik, et al.
(författare)
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Oxygen-Controlled Phase Segregation in Poly(N‑isopropylacrylamide)/Laponite Nanocomposite Hydrogels
- 2013
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 29, s. 371-379
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Tidskriftsartikel (refereegranskat)abstract
- The combination of nanoparticles and polymers into nanocomposite gels has been shown to be a promising route to creating soft materials with new or improved properties. In the present work, we have made use of Laponite nanoparticles in combination with a poly(N-isopropylacrylamide) (PNIPAAM)polymer and describe a phenomenon taking place during the polymerization and gelling of this system. The presence of small amounts of oxygen in the process induces two distinctly separated phases, one polymer-rich and one polymer-deficient water−clay phase. Complex interactions among clay, oxygen, and the polymer are found to govern the behavior of these phases. It is also observed that the initial clay concentration can be used to control the volume fraction of the polymer-deficient phase directly. The dynamics of the phase boundary is found to be dependent on water penetration and in general to exhibit non-Fickian behavior. An approach using video recording to monitor hydrogel swelling is also presented, and its advantages are addressed.
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| 10. |
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