898 research outputs found
Performance Analysis of PV Power Plants Across Norway
This thesis examines hourly aggregated data from 501 photovoltaic (PV) installations, builds a better knowledge foundation about the geographical performance of PV systems in Norway, and provides a groundwork for how PV datasets with limited metadata can be analyzed. Metadata is supplemented with inferred tilt and azimuth by analyzing the power and irradiance relationship at different orientations, with 1-degree intervals. When tested with a known PV installation, the result shows a median accuracy of 12.2 and 14.1 degrees for tilt and azimuth, respectively. To analyze the performance of PV installations, the power output data is filtered with a linear filter (RANSAC) and a non-linear polynomial filter. The latter shows promising results, as long as specific requirements regarding the number of available timestamps are available. Unknown capacity units are inferred by selecting highly probable units (Wp, kW_p, and MW_p) and finding highly probable specific yields. Installations, where highly probable specific yields are not found using these units have been removed from further analysis
Ground Improvement by Optimized Preload Program
Preloading of sites underlain by compressible soils is a well-established site development procedure to reduce post-construction settlements of structures supported on shallow foundations. Considerable reduction in the preload duration can often be achieved by installation of vertical drains. It is desirable to extend vertical drains down through the compressible soils impacted by the preload and terminate the drains within relatively incompressible soils. If this cannot be achieved, then the potential exists for unacceptable post-construction differential settlements due to greater settlement below the center of the building than along its edges. If no relatively incompressible soils exist below the compressible soils impacted by the preload, the length of the vertical drains may be increased along the perimeter to achieve similar preload settlements throughout the site due to lesser increases in soil stresses along the preload edges. The site development loads at the subject site, comprising fill required to raise site grades by about 4.0 m and building loads, would induce consolidation below the maximum depth reachable with conventional wick drain mandrels. These loads would induce the greatest post-construction building settlements near the center of the site due to a smaller increase in soil stresses along the perimeter of the site. Hence, increasing the postconstruction settlements along the site perimeter, relative to those below the center of the development, would reduce the post-construction differential building settlements. In an attempt to reduce the post-construction differential building settlements, the wick drains at the subject site were installed to three depths ranging between 25 m and 35 m with the depth reducing towards the building perimeter. This paper will briefly present the results of geotechnical site investigations and the inferred subsurface conditions, which will be followed by a discussion on the preload design and performance. Detailed monitoring was carried out of surface settlement gauges and of deep settlement gauges installed to 43 m depth, in addition to monitoring of pneumatic and standpipe piezometers. The results of the instrumentation monitoring will be presented to assess the conformance of actual preload settlements with those predicted
Singularly Perturbed Boundary-Focus Bifurcations
We consider smooth systems limiting as to piecewise-smooth
(PWS) systems with a boundary-focus (BF) bifurcation. After deriving a suitable
local normal form, we study the dynamics for the smooth system with using a combination of geometric singular perturbation theory
and blow-up. We show that the type of BF bifurcation in the PWS system
determines the bifurcation structure for the smooth system within an
dependent domain which shrinks to zero as ,
identifying a supercritical Andronov-Hopf bifurcation in one case, and a
supercritical Bogdanov-Takens bifurcation in two other cases. We also show that
PWS cycles associated with BF bifurcations persist as relaxation cycles in the
smooth system, and prove existence of a family of stable limit cycles which
connects the relaxation cycles to regular cycles within the
dependent domain described above. Our results are applied to models
for Gause predator-prey interaction and mechanical oscillation subject to
friction
Evaluation and selection of lower limb lymphedema patients for lymphaticovenular anastomosis: A prospective study
Background: Lymphaticovenular anastomosis (LVA) with supramicrosurgical technique has recently gained popularity as a treatment method for patients with lymphedema. The aim of this study was to prospectively evaluate objective changes in leg volume in patients operated with LVA for lymphedema in the lower extremity, and to find positive predictors for the treatment method to facilitate the location of the venules and lymphatic vessels.
Patients & Methods: 31 consecutive patients with lymphedema in the lower extremity and positive pitting test were examined with lymphoscintigraphy and indocyanine green (ICG) lymphography. The causes of the lymphedema were either cancer or unknown cause/primary lymphedema. Fourteen of the patients with pathological lymphangiographic patterns were chosen for surgery and 12 of them were operated with one to four LVAs each. The lymphedema volume in the lower extremity was measured preoperatively, 6- and 12 months after surgery according to the truncated cone formula with the patient \u301s contralateral leg used as control. Ten patients had unilateral lymphedema and two patients had bilateral lymphedema.
Results: Five of 12 patients showed between 1-8 % edema reductions in the lower extremity after 12 months. With examination considering edema duration, number of anastomoses, radiotherapy and lymph node dissection we found a 6,2 % difference in edema reduction between patients who had undergone lymph node dissection and those who had not (p=0.03). Conclusions: The current study indicates that supramicrosurgery with LVA may reduce edema volumes, where the most distinctive positive predictor for edema reduction with LVAs was previous lymph node dissection
Report From Surveys To Assess Harp And Hooded Seal Pup Production In The Greenland Sea Pack-Ice In 2022
Cruise no.: 2022703 : The 2022 survey of harp and hooded seal pup production in the Greenland Sea was carried out to obtain updated estimates to be used to assess current status of these two seal stocks. Since a similar survey in 2018 indicated a 40% reduction in harp seal pup production since the 2012 survey, and the continued lack of increase in pup production of the severely depleted hooded seal stock despite its protection from hunting since 2007, a new survey after a period of only 4 years was urgent. The survey was carried out using well established methodologies for these species, including 1) reconnaissance of the drift ice breeding habitat from a helicopter based on the research icebreaker R/V Kronprins Haakon and a fixed-wing aircraft stationed at Constable Pynt in East Greenland, 2) deploying GPS beacons around the identified breeding areas to monitor its displacement in the East Greenland Current, 3) carrying out staging surveys to monitor the pup age structure and estimate the optimal day of pup counting as well as correction factors accounting for pups not present on the ice at the time of counting, and 4) conducting aerial photographic surveys using the fixed-wing aircraft. Ice conditions in the Greenland Sea were similar as those experienced in 2018, with a relatively narrow band of pack ice over the shelf break near the coast of East Greenland. Seal whelping patches were initially discovered on March 21 & 22nd, within an area stretching from 72°53âN / 16°42âW in the north to 71°51âN / 17°30âW in the south. Five GPS beacons were deployed at the main whelping patches within this area, allowing us to track the continuous drift due to strong northerly winds during the period between initial reconnaissance and the final pup counting. Pup staging surveys were carried out on March 22nd, 23rd, 25th, 28th and 30th, providing us with a solid dataset with which to assess the development of pup age dynamics, determine the optimal day for photographic surveys, and to estimate correction factors to account for pups absent from the ice during the photographic surveys. The final photographic surveys were carried out on March 28th in a relatively narrow (20-30 nm) N/S band stretching from 71°00âN / 20°00âW in the NE to 69°34âN / 20°36âW in the SW. In total, 2,463 images were obtained during the aerial photographic survey, and following pre-processing (georeferencing and ortorectification), these will be analysed both manually and using dedicated machine learning systems, to determine the number of pups present in images. Results will be used to estimate the total 2022 pup production for each species and will also be combined with estimates from previous years to estimate the population sizes using the dedicated population dynamics model. The entire updated dataset will be made available to the upcoming ICES benchmarking meeting for harp and hooded seal population modelling, and results will finally be evaluated at the upcoming meeting of the ICES WGHARP working group in 2023.Report From Surveys To Assess Harp And Hooded Seal Pup Production In The Greenland Sea Pack-Ice In 2022publishedVersio
Report From Surveys To Assess Harp And Hooded Seal Pup Production In The Greenland Sea Pack-Ice In 2022
Source at https://www.hi.no/en/hi/nettrapporter/toktrapport-en-2022-7.Cruise no.: 2022703 :
The 2022 survey of harp and hooded seal pup production in the Greenland Sea was carried out to obtain updated estimates to be used to assess current status of these two seal stocks. Since a similar survey in 2018 indicated a 40% reduction in harp seal pup production since the 2012 survey, and the continued lack of increase in pup production of the severely depleted hooded seal stock despite its protection from hunting since 2007, a new survey after a period of only 4 years was urgent. The survey was carried out using well established methodologies for these species, including 1) reconnaissance of the drift ice breeding habitat from a helicopter based on the research icebreaker R/V Kronprins Haakon and a fixed-wing aircraft stationed at Constable Pynt in East Greenland, 2) deploying GPS beacons around the identified breeding areas to monitor its displacement in the East Greenland Current, 3) carrying out staging surveys to monitor the pup age structure and estimate the optimal day of pup counting as well as correction factors accounting for pups not present on the ice at the time of counting, and 4) conducting aerial photographic surveys using the fixed-wing aircraft. Ice conditions in the Greenland Sea were similar as those experienced in 2018, with a relatively narrow band of pack ice over the shelf break near the coast of East Greenland. Seal whelping patches were initially discovered on March 21 & 22nd, within an area stretching from 72°53âN / 16°42âW in the north to 71°51âN / 17°30âW in the south. Five GPS beacons were deployed at the main whelping patches within this area, allowing us to track the continuous drift due to strong northerly winds during the period between initial reconnaissance and the final pup counting. Pup staging surveys were carried out on March 22nd, 23rd, 25th, 28th and 30th, providing us with a solid dataset with which to assess the development of pup age dynamics, determine the optimal day for photographic surveys, and to estimate correction factors to account for pups absent from the ice during the photographic surveys. The final photographic surveys were carried out on March 28th in a relatively narrow (20-30 nm) N/S band stretching from 71°00âN / 20°00âW in the NE to 69°34âN / 20°36âW in the SW. In total, 2,463 images were obtained during the aerial photographic survey, and following pre-processing (georeferencing and ortorectification), these will be analysed both manually and using dedicated machine learning systems, to determine the number of pups present in images. Results will be used to estimate the total 2022 pup production for each species and will also be combined with estimates from previous years to estimate the population sizes using the dedicated population dynamics model. The entire updated dataset will be made available to the upcoming ICES benchmarking meeting for harp and hooded seal population modelling, and results will finally be evaluated at the upcoming meeting of the ICES WGHARP working group in 2023
Verdivurdering av Spitsbergen Travel AS
Denne mastergradsoppgaven er utfÞrt med det formÄl Ä gjennomfÞre en verdivurdering av
Spitsbergen Travel AS. Oppgaven starter med utredning om bakgrunnen for problemstillingen
og problemdefinisjon. Vi presenterer Spitsbergen Travel AS, historien bak selskapet og selskapet
slik det fremstÄr i dag. Vi beskriver deretter den metodiske tilnÊrmingen og den teoretiske
referanserammen vi har valgt for Ă„ kunne svare pĂ„ problemstillingen â Hva var verdien av
Spitsbergen Travel AS ved utgangen av 2006, og i hvor stor grad pÄvirkes verdianslaget av
endringer i selskapets rammebetingelser?â
Vi gjennomfĂžrer en ekstern og intern analyse av selskapet for dermed Ă„ kunne si noe om hvordan
vi mener det er sannsynlig at markedet vil utvikle seg og hvor godt selskapet stÄr rustet for Ä
mÞte utfordringene som mÞter dem i tiden som kommer. Vi ser pÄ selskapenes historiske
utvikling pÄ parametre som omsetning, kostnader samt Þkonomiske prestasjonsmÄl. Ut i fra disse
faktorene sammen med den interne og eksterne analysen har vi kommet frem til et budsjett for de
neste ni Ă„rene. Dette trendfremskrevne budsjettet sammen med selskapets historiske utvikling
danner grunnlaget for verdivurderingene vi har gjennomfĂžrt for Spitsbergen Travel AS.
Ved hjelp av ulike verdivurderingsmetoder har vi kommet frem til at verdien pÄ Spitsbergen
Travel AS ligger i omrÄdet 270 MNOK. Vi har gjennomfÞrt en senarioanalyse der vi ser i hvor
stor grad dette verdianslaget pÄvirkes av endringer i sentrale parametre som budsjettert
omsetning, endring i kostnadene, evig vekstfaktor, selskapets egenkapitalavkastningskrav, samt
hvor stor effekt det spesielle skatteregimet pÄ Svalbard innvirker pÄ verdivurderingen
A Signal-Passing DNA-Strand-Exchange Mechanism for Active Self-Assembly of DNA Nanostructures
DNA nanostructured tiles play an active role in their own self-assembly in the system described herein whereby they initiate a binding event that produces a cascading assembly process. We present DNA tiles that have a simple but powerful property: they respond to a binding event at one end of the tile by passing a signal across the tile to activate a binding site at the other end. This action allows sequential, virtually irreversible self-assembly of tiles and enables local communication during the self-assembly process. This localized signal-passing mechanism provides a new element of control for autonomous self-assembly of DNA nanostructures
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