| 41. |
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| 42. |
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| 43. |
- Gustafsson, Magnus, et al.
(author)
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Erratum: Observing the stereodynamics of chemical reactions using randomly oriented molecular beams ( Journal of Chemical Physics (2006) 124 (241105))
- 2006
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In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 125:22
-
Journal article (other academic/artistic)abstract
- A new method is demonstrated to study the stereodynamics of simple chemical reactions that does not require the use of oriented (or aligned) molecular beams or measurements of the orientation state of product molecules. Instead, it is shown that by numerically combining accurate measurements of the state-to-state differential cross section for two or more rotational states of the reagent molecule, the separate contribution from the individual helicity states can be extracted. New molecular beam experiments are conducted for the D+H2→HD+Hreaction that confirm the validity of the method.
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| 44. |
- Gustafsson, Mats, et al.
(author)
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Inandningsbara partiklar från dubbdäcksslitage av vägbana : egenskaper och inflammatoriska effekter i mänskliga luftvägsceller. utdrag ur WearTox-projektet (VTI rapport 520)
- 2005
-
Reports (other academic/artistic)abstract
- The aims of this project have been to describe PM10 from studded tyre wear and to study their inflammatory effects in human airway cells. The VTI circular road simulator has been used to generate "clean" wear particles from two different pavements; asphalt concrete (ABT) and stone mastic asphalt (ABS), with granite respectively quartzite as the main stone materials. The advantage of using the road simulator is that the contribution from other sources can be minimised. During the project time, the project was expanded also to study particle generation by non-studded winter tyres (friction tyres) and two kinds of winter sanding agents, namely washed crushed stone and unwashed natural sand in combination with both studded and friction tyres. Most of these parts of the project are presented in VTI report 520. The results show that pavement wear by studded tyres generates about 40-50 times as much PM10 as that by friction tyres, but also that the ABT pavement generates several times more PM10 than the ABS pavement. The size distribution within PM10 has a maximum around 3-4 ?m and more than 95 % of the mass is larger than 1 ?m. PM10 is totally dominated by fresh stone material. A fraction of very small particles, with a number concentration peak at around 30-40 nm, was also discovered. Their origin is unknown, but since the number distribution shifted depending on which tyre type was used, a possible origin is the tyres. In the cell studies the inflammation potential of the wear particles was compared with PM10 from Hornsgatan in Stockholm and PM10 from a Stockholm subway station. Later on in the project, diesel particles were made available for comparison. The cell study results show that PM10 from the ABT pavement is at least as inflammatory as diesel particles and more inflammatory than PM10 from the subway. The PM10 from Hornsgatan generally had the highest potential, but PM10 from the ABT pavement was often in parity. This despite the fact that the Hornsgatan PM10 were the only particle sample where endotoxin could be detected. Endotoxin causes an additive effect in studies of inflammation potential. PM10 from the ABS pavement generally had a lower potential than PM10 from the ABT pavement.
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| 45. |
- Gustafsson, Mats, et al.
(author)
-
Inandningsbara partiklar i järnvägsmiljöer
- 2006
-
Reports (other academic/artistic)abstract
- Airborne particles from railroad traffic have been identified as an air pollution problem mainly in tunnel environments. As a result of the introduction of the environmental quality standard for inhalable particles in Sweden 2005, the interest in railroad particle pollution has increased. The present report focuses on the variation of PM10 (inhalable particles) in some railroad environments under and above ground, the way these relate to traffic and on the particles' size distributions and elemental composition. The results show that particle concentrations in above ground railroad environments do not exceed the environmental quality standard during the campaigns. Diurnal mean values of PM10 range between 19 to 25 microg/m3. On the contrary, the diurnal mean concentrations on the platforms of the underground stations Arlanda Central and Arlanda South are far above the limit value (237 and 88 microg/m3 respectively) and clear diurnal and weekly patterns in PM10 concentration, co-fluctuating with traffic, can be identified. The particle mass size distribution has an obvious peak around 5-7 ?m at Arlanda C, and slightly smaller, 2-3 microm, at Arlanda S. The concentrations of both PM10 and ultrafine particles (< 0,1 microm) vary a lot depending on different trains. Especially the ultrafine particles seem to be emitted from certain trains, but it has not been possible to identify the source of these particles. The elemental composition of the particles in the tunnel environments was dominated by iron (84 % and 74 % respectively in Arlanda C and Arlanda S), but also other metals, like Cu, Zn, Cr, Ni and Sb (only at Arlanda C) have relatively high concentrations. The tunnel measurements also give some interesting results regarding possible measures against high particle concentrations. Washing of the tunnel walls and floor was carried out on two consecutive nights, but it had no noticeable results on particle concentrations. This implies that a dominant proportion of the particles is directly emitted rather than resuspended. On certain nights, the concentrations of all particle size fractions sank to very low levels, lasting till the morning traffic began. This implies effective self ventilation during these hours. Measurements in several different environments on Stockholm central station show that PM10 vary several tens of microg/m3. Activity, related to both traffic and people, increases particle concentration. The highest concentrations were measured inside the waiting hall. Nevertheless, the concentrations on the platforms were generally at least as high as in the busy street environment outside the station. During a railroad travel, the PM10 and PM2,5 concentrations were generally low, but increase at stops and, most prominently, on entering the Arlanda airport railroad tunnels. The PM2,5 proportion is considered high, contributing to approximately 50-80 % of PM10. The sources of railroad emitted PM10 are likely to be rails, wheels and brakes, but a source apportionment has not been accomplished in this project.
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| 46. |
- Gustafsson, Magnus, et al.
(author)
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Infrared absorption spectra by H2–He collisional complexes : The effect of the anisotropy of the interaction potential
- 2000
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In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 113:9, s. 3641-3650
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Journal article (peer-reviewed)abstract
- As an extension of previous work which was based on the isotropic interaction approximation, absorption spectra in the rotational and fundamental bands of H2, induced by collisions with He, are calculated by numerical integration of the close-coupled Schrödinger equation to account for the anisotropy of the interaction potential. A refined quantum chemical dipole surface of interactingH2–He pairs is also obtained with an extended grid of molecular geometries. This dipole surface agrees generally well with previous results, but is smaller by about 5% in the isotropic overlap term which is significant only in the fundamental band. The effects of the anisotropy of the interaction are to reduce the peak intensities of the Q and S lines by roughly 10% and to increase absorption in the far wings by a similar amount. The accuracy of the dipole surface as well as that of the ab initiointeraction potential that enters the calculations of the spectra are believed to permit the prediction of absolute spectral intensities with an accuracy of about ±5%. Comparisons with the available measurements show very good agreement of the shapes of the spectral profiles, but the absolute intensities differ by up to 10% in some cases. These remaining differences between theory and measurements appear to be random and are generally smaller than the differences among comparable measurements. Our results should therefore provide a reliable basis for predicting absorption by H2–He pairs for temperatures and frequencies for which no laboratory measurements exist. This fact is of a special interest, for example, for the spectroscopic analyses of the atmospheres of the outer planets.
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| 47. |
- Gustafsson, Martin
(author)
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Integrated low power ultrasound sensor interfaces
- 2005
-
Licentiate thesis (other academic/artistic)abstract
- Imagine that the technical development can take the ultrasound measurement systems from the large piece of machinery today, to a coin size system tomorrow. The factor that has reduced the size of electronic systems over time is integration and integrated circuits. In this thesis circuit simulator models of complete ultrasound systems are used to design custom integrated circuits. These circuits are optimized for low power consumption and small size. The models that are used predict the acoustic behavior of an ultrasound system in a simulated measurement situation. This allows the design of integrated electronics to be customized to a specific measurement application, where performance can be validated, in one tool only. The work in this thesis is excitation and reception electronics for general ultrasound measurement equipment, as well as specific electronics aimed for the ultrasound energy measurement situation. These electronic circuits show that size and power consumption of ultrasound measurement systems can be reduced significantly with the use of integration.
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| 48. |
- Gustafsson, Magnus, et al.
(author)
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Integrated sample preparation and MALDI mass spectrometry on a microfluidic compact disk.
- 2004
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In: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 76:2
-
Journal article (peer-reviewed)abstract
- High-throughput microfluidic processing of protein digests integrated with matrix-assisted laser desorption/ionization (MALDI) mass spectrometry on a compact disk (CD) is described. Centrifugal force moves liquid through multiple microstructures, each containing a 10-nL reversed-phase chromatography column. The CD enables parallel preparation of 96 samples with volumes ranging from one to several microliters. The peptides in the digests are concentrated, desalted, and subsequently eluted from the columns directly into MALDI target areas (200 x 400 microm) on the CD using a solvent containing the MALDI matrix. After crystallization, the CD is inserted into the MALDI instrument for peptide mass fingerprinting and database identification at a routine sensitivity down to the 200-amol level. Detection of proteolytic peptides down to the 50-amol level is demonstrated. The success rate of the CD technology in protein identification is about twice that of the C(18) ZipTips and standard MALDI steel targets. The CDs are operated using robotics to transfer samples and reagents from microcontainers to the processing inlets on the disposable CD and spinning to control the movement of liquid through the microstructures.
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| 49. |
- Gustafsson, Marie, 1980-, et al.
(author)
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Modeling Contexts of Knowledge Sharing in an Online Community for Oral Medicine
- 2007
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In: CONTEXT '07 Doctorial Consortium Proceedings. - Roskilde : Roskilde University. ; , s. 30-43
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Conference paper (peer-reviewed)abstract
- To support knowledge sharing between practitioners of oral medicine throughout Sweden, the SOMWeb system for community collaboration has been constructed, based on Semantic Web technologies. A large function of the system is to support the discussion of difficult and interesting cases at a monthly telephone conference. From our observations of these meetings, a the users’ responses to a questionnaire, and discussions with users, we find that many of the improvements that can be made to enable further use of the system relate to adding the use of context. Some initial thoughts on what would be relevant to represent in relation to context are given, such as the experience of the practitioner, the reason for adding a case to the system, and the current activity of the user. The long-term aims of this work is to identify aspects of context relevant to online communities of practice in healthcare, and to investigate how these contexts can be modeled using Semantic Web technologies.
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| 50. |
- Gustafsson, Mats, et al.
(author)
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Modeling the exposure of roadside environment to airbone salt : Case study
- 2005
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In: Transportation Research Circular E-C063. - Washington, D.C. : Transportation Research Board, National Research Council. ; , s. 296-306
-
Book chapter (other academic/artistic)abstract
- A field study was performed in order to investigate the relationships between the salt use, the mechanisms affecting the salt emission, dispersion and the salt exposure in a modeling approach. The salt was collected on gauze filter salt vanes at distances of 2.5 m to 100 m from the road, allowing a time resolution of 30 minutes to 24 hour exposure time. The results will be implemented in a winter maintenance management model under development by the Swedish National Road and Transport Research Institute (VTI). The results showed that the roadside exposure to airborne salt is strongly related to the wind direction. The road conditions of packed snow and thin ice seemed to temporarily abate the roadside exposure by capturing the salt on the road surface. Even at a distance of 100 m from the road a positive relation of the wind sum and chloride deposition showed on days with strong winds. The modeling approach indicate the importance of residual salt, traffic, road surface characteristics, and wind for roadside exposure but also that there are several aspects of these variables that need further investigations.
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