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Sökning: WFRF:(Ekholm Johan)

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1.
  • Beecken, Jörg, 1982, et al. (författare)
  • Airborne emission measurements of SO2, NOx and particles from individual ships using a sniffer technique
  • 2014
  • Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 7:7, s. 1957-1968
  • Tidskriftsartikel (refereegranskat)abstract
    • A dedicated system for airborne ship emission measurements of SO2, NOx and particles has been developed and used from several small aircraft. The system has been adapted for fast response measurements at 1 Hz, and the use of several of the instruments is unique. The uncertainty of the given data is about 20% for SO2 and 24% for NOx emission factors. The mean values with one standard deviation for multiple measurements of 158 ships measured from the air on the Baltic and North Sea during 2011 and 2012 show emission factors of 18.8+/-6.5 g kg(fuel)(-1), 66.6+/-23.4 g kg(fuel)(-1) and 1.8+/-1.3 1016 particles kg(fuel)(-1) for SO2, NOx and particle number, respectively. The particle size distributions were measured for particle diameters between 15 and 560 nm. The mean sizes of the particles are between 45 and 54 nm dependent on the distance to the source, and the number size distribution is monomodal. Concerning the sulfur fuel content, around 85% of the monitored ships comply with the International Maritime Organization (IMO) limits. The reduction of the sulfur emission control area (SECA) limit from 1.5 to 1% in 2010 appears to have contributed to reduction of sulfur emissions that were measured in earlier studies from 2007 to 2009. The presented method can be implemented for regular ship compliance monitoring.
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2.
  • Beecken, Jörg, 1982, et al. (författare)
  • Emission factors of SO2, NOx and particles from ships in Neva Bay from ground-based and helicopter-borne measurements and AIS-based modeling
  • 2015
  • Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 15:9, s. 5229-5241
  • Tidskriftsartikel (refereegranskat)abstract
    • Emission factors of SO2, NOx and size-distributed particle numbers were measured for approximately 300 different ships in the Gulf of Finland and Neva Bay area during two campaigns in August/September 2011 and June/July 2012. The measurements were carried out from a harbor vessel and from an Mi-8 helicopter downwind of passing ships. Other measurements were carried out from shore sites near the island of Kronstadt and along the Neva River in the urban area of Saint Petersburg. Most ships were running at reduced speed (10 kn), i.e., not at their optimal load. Vessels for domestic and international shipping were monitored. It was seen that the distribution of the SO2 emission factors is bi-modal, with averages of 4.6 and 18.2 gSO(2) kg(fuel)(-1) for the lower and the higher mode, respectively. The emission factors show compliance with the 1% fuel sulfur content Sulfur Emission Control Areas (SECA) limit for 90% of the vessels in 2011 and 97% in 2012. The distribution of the NOx emission factor is mono-modal, with an average of 58 gNO(x) kg(fuel)(-1). The corresponding emission related to the generated power yields an average of 12.1 gNO(x) kWh(-1). The distribution of the emission factors for particulate number shows that nearly 90% of all particles in the 5.6 nm to 10 mu m size range were below 70 nm in diameter. The distribution of the corresponding emission factors for the mass indicates two separated main modes, one for particles between 30 and 300 nm and the other for above 2 mu m. The average particle emission factors were found to be in the range from 0.7 to 2.7 x 10(16) particles kg(fuel)(-1) and 0.2 to 3.4 gPM kg(fuel)(-1), respectively. The NOx and particulate emissions are comparable with other studies. The measured emission factors were compared, for individual ships, to modeled ones using the Ship Traffic Emission Assessment Model (STEAM) of the Finnish Meteorological Institute. A reasonably good agreement for gaseous sulfur and nitrogen emissions can be seen for ships in international traffic, but significant deviations are found for inland vessels. Regarding particulate mass, the values of the modeled data are about 2-3 times higher than the measured results, which probably reflects the assumptions made in the modeled fuel sulfur content. The sulfur contents in the fuel retrieved from the measurements were lower than the previously used assumptions by the City of Saint Petersburg when carrying out atmospheric modeling, and using these measurements it was possible to better assess the impact of shipping on air quality.
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3.
  • John Mukkattukavil, Deepak, et al. (författare)
  • Resonant inelastic soft x-ray scattering on LaPt2Si2
  • 2022
  • Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 34:32, s. 324003-
  • Tidskriftsartikel (refereegranskat)abstract
    • X-ray absorption and resonant inelastic x-ray scattering spectra of LaPt2Si2 single crystal at the Si 2p and La 4d edges are presented. The data are interpreted in terms of density functional theory, showing that the Si spectra can be described in terms of Si s and d local partial density of states (LPDOS), and the La spectra are due to quasi-atomic local 4f excitations. Calculations show that Pt d-LPDOS dominates the occupied states, and a sharp localized La f state is found in the unoccupied states, in line with the observations.
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4.
  • Kärrholm, Johan, 1951, et al. (författare)
  • Effects on work resumption of a co-operation project in vocational rehabilitation. Systematic, multi-professional, client-centred and solution-oriented co-operation
  • 2006
  • Ingår i: Disabil Rehabil. - : Informa UK Limited. - 0963-8288 .- 1464-5165. ; 28:7, s. 457-67
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: The present aim was to evaluate the effect of systematic multi-professional co-ordinated rehabilitation (the Stockholm Co-operation Project) on the number of days' sick leave during the first and second half-years after the rehabilitation co-ordination period, compared to the year before. Another aim was to evaluate the economic effects at national level. METHOD: A matched-pairs design was used. The study group was based on 64 rehabilitees employed by a public employer in Stockholm, who took part in a systematic multi-professional co-operation project. To obtain pairs, the 64 individuals were individually matched with 64 people who received conventionally organised rehabilitation. Thus, there were 128 subjects altogether. RESULTS: The study group had substantially less sick leave days per month than the comparison group during the second half-year after the rehabilitation co-ordination period. The effect was even greater in a subgroup with more previous sick leave. During the first half-year after the intervention the comparison group had relatively more sick leave. No effect was found for a subgroup with less previous sick leave. The economic benefit of the intervention was estimated to 1,278 euros per month and person based on the whole group, and to 2,405 euros per month and person based on those with more sick leave. CONCLUSIONS: People who undergo co-ordinated rehabilitation have more working days after the intervention period than those with conventional rehabilitation. This way for rehabilitation actors to co-operate gives better outcomes for rehabilitation cases with long previous sick leave, but not for cases with less previous sick leave. It also generates economic gains at several levels.
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5.
  • Lagerkvist, Claes-Ingvar, et al. (författare)
  • Colours of Distant Solar System Bodies
  • 2000
  • Ingår i: Minor Bodies in the Outer Solar System. - Berlin/Heidelberg : Springer Berlin/Heidelberg. - 9783540411529 - 9783540400349 ; , s. 71-73
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The NTT at La Silla, Chile and NOT on La Palma were used for VRI photometry of 9 Edgeworth-Kuiper objects and 3 Centaurs. For the NOT observations growth-curve fitting was applied in the photometric reductions. The spread in colour of the observed Centaurs and Edgeworth-Kuiper objects is large.
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6.
  • Mellqvist, Johan, 1965, et al. (författare)
  • Certification of an aircraft and airborne surveillance of fuel sulfur content in ships at the SECA border
  • 2017
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • In 2015 new rules from the IMO and legislation from EU (Sulfur directive) and the US requires ships to run with maximum fuel sulfur content (FSC) of 0.1 % m/m in northern European and North American waters. In order to promote a level playing field within the shipping sector, there is a need for measurement systems that can make effective compliance control and this is the main objective of the CompMon project, funded through the European CEF program (Connecting Europe Facility). As part of this project, a sensor system has been certified for ship surveillance measurements in a Piper Navajo aircraft and it has been demonstrated for airborne measurements of FSC in individual ships on the English Channel. The measurement system consists of an optical module which measures total emissions of SO2 and NO2 in g/s and a sniffer system by which FSC is retrieved from extractive measurements of SO2 and CO2. It can be used from fixed sites, patrol vessels and from aircraft. The advantage with airborne surveillance is the capability to check ships that are operating in the main shipping lanes, up to 200 nautical miles from shore. The precision of the estimated FSC from the sniffer system is 0.05 % m/m and hence at the 95 % confidence limit, ships above a FSC of 0.2 % m/m can be checked. The sniffer system also has a negative bias in the FSC of approx- imately 0.04 % m/m which is accounted for in the FSC calculations. The optical system has larger measurement uncertainties than the sniffer but it is intended mostly for guid- ance of other controls. As part of the CompMon project, a measurements campaign with the Navajo Piper aircraft was carried out at the SECA (Sulfur Emission Control Area) border in the English Channel at longitude 5 W. Six flight missions with duration of 4 to 5 hours were carried out from September 2 to 10, 2016, flying from Brest airport. In this manner it was possible to cover the longitude range 2o - 6o W. During the campaign, 114 ships were measured with the sniffer system, corresponding to 71 ships inside the SECA and 42 ships outside. The level of compli- ance inside the SECA was here 87 % and this is considerably lower than measurements carried out elsewhere within CompMon in other parts of the SECA (95-99 %). Two thirds of the non-complying vessels were leav- ing the SECA. With the optical system 110 individual ships were measured, 42 outside and 68 inside the SE- CA. The measurements show a similar pattern as the sniffer data but with a few false values. Nevertheless it is shown that both low and high FSC ships will be classified correctly with about 80-90 % probability with the optical system and this system is hence very promising as a tool to guide further compliance controls.
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7.
  • Mellqvist, Johan, 1965, et al. (författare)
  • Fixed remote surveillance of fuel sulfur content in ships from fixed sites in the Göteborg ship channel and Öresund bridge
  • 2017
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • In 2015 new rules from the IMO and legislation from EU (Sulfur directive) and the US requires ships to run with maximum fuel sulfur content (FSC) of 0.1 % m/m in northern European and North American waters. In order to promote a level playing field within the shipping sector, there is a need for measurement systems that can make effective compliance control and this is the main objective of the CompMon project, funded through the European CEF program (Connecting Europe Facility). As part of this project, an automatic sniffer sensor system has been applied in the Göteborg ship channel at the Älvsborg island during 3 years (2014- 2016) and at the Öresund Bridge during two months at the end of 2016. The typical distances from the ships here varied between 500 -1000 m. The sniffer system is based on several extractive instruments measuring concentrations of SO2 and CO2 and others species, such as NOx, in the ship emission plumes that drift over the measurement station. In addition to fixed stations, the system can also be used from mobile platforms such as harbor patrol vessels and aircraft. From the data above, together with information about the ships from AIS (Automatic Identification System) and wind data, the FSC is automatically calculated and the ship is identi- fied. This is done using software developed as part of this project (Single Emitter identification Tool). The measurement precision (1σ) of the sniffer system is approx. 0.04 % m/m for ships using a FSC of 0.1 % m/m. The sniffer system also has a negative bias in the measured FSC, varying between 0.04 % to 0.08 % m/m and this is accounted for when calculating the threshold for non-compliance. Based on the above, it is possible to identify ships with FSC above 0.18 % m/m with 95% confidence limit, if the bias is corrected for statistically. For the measurements at the Älvsborg island site in 2014 and 2015, the corresponding limit is higher, 0.29 % m/m, due to a measurement artifact that was eliminated in 2016. On board measurements in 2015 and 2016 by the Swedish port state control authority shows that most non-compliant ships had FSCs be- tween 0.1 % to 0.2 % m/m when controlled at berth and this is generally below the 95% confidence limit threshold of the sniffer. Therefore many non-compliant ships will not be detected when using the sniffer close to harbors and a more precise sensor is therefore preferred. The measurements at the Älvsborg island were carried out during a time period when the allowed FSC limit changed significantly. The data for 2014, corresponding to more than 4000 measurements of 500 individual ships, shows that 99 % of the ships were using compliant fuel below the FSC limit of 1 % m/m. In 2015 the FSC limit changed to 0.1 % m/m. The measurements in 2015 and 2016, corresponding to the same amount of ships as in 2014, showed that 91.5 % and 98 %, respectively, were using compliant fuel with respect to FSC. The lower compliance rate in 2015 compared to 2016 is potentially influenced by measurement artifacts that were later eliminated in 2016. At the Öresund Bridge. 58 ships were measured as part of the CompMon pro- ject. The measurements continued another month with support from the interreg project Envisum, with anoth- er 62 ships measured. The compliance level at the Öresund Bridge corresponds to 98 %. This is actually com- parable to the corresponding measurements elsewhere and at the Älvsborg island site during the same time period.
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8.
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9.
  • Mellqvist, Johan, 1965, et al. (författare)
  • Quantification of stack emissions from marine vessels
  • 2016
  • Ingår i: Air and Waste Management Association - Air Quality Measurement Methods and Technology Conference 2016. - 9781510822535 ; , s. 416-421
  • Konferensbidrag (refereegranskat)abstract
    • Ship emission data from fixed and mobile platforms were obtained during 5 weeks in October and November of 2015. The main objective was to study the "real life" ship emissions of gases and particles in different modes of ship operation in the vicinity of the harbor, from open sea to berth. These emissions can be used to calculate the impact of shipping activities on air quality in the LA basin. Since ships are supposed to run on low sulfur fuel it is interesting how the new low sulfur fuel impacts also emissions of particles, in addition to sulfur. During the project we found several ships running on high sulfur fuel. During the presentation we will describe the method and show example of data from the project.
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10.
  • Mellqvist, Johan, 1965, et al. (författare)
  • Remote Quantification of Stack Emissions from Marine Vessels
  • 2016
  • Ingår i: A&WMA’s 109th Annual Conference & Exhibition, New Orleans, Louisiana, June 2016. - 1052-6102. ; 1, s. 579-583
  • Konferensbidrag (refereegranskat)abstract
    • Stationary and mobile (on-vessel) measurements of ship specific emission factors and total emission were carried out in the port of Los Angeles and Long Beach. The measurement techniques developed to characterize individual ship emissions were presented. The data were obtained with a zenith DOAS technique for NO 2 and "in-situ" sniffer technique for SO 2 , NO x , CO 2 , and particulates. The measured particle properties corresponded to particulate number, particulate mass, and black and organic carbon. Total emissions of NO 2 from the harbors were also obtained through mobile optical zenith sky measurements. The potential VOC emissions were investigated when fueling the ships and other VOC sources in the harbor using techniques like the Solar Occultation Flux technique. This is an abstract of a paper presented at the A & WMA's 109th Annual Conference & Exhibition (New Orleans, LA 6/20-23/2016).
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