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- Andersson, Mats, 1963, et al.
(författare)
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Adsorption and reactions of O2 and D2 on small free palladium clusters in a cluster-molecule scattering experiment
- 2010
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Ingår i: Journal of Physics Condensed Matter. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 22:33, s. 334223-
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption of oxygen and hydrogen (deuterium) on small neutral palladium clusters was investigated in a cluster beam experiment. The beam passes through two low-pressure reaction cells, and the clusters, with and without adsorbed molecules, are detected using laser ionization and mass spectrometry. Both H2 and O2 adsorb efficiently on the palladium clusters with only moderate variations with cluster size in the investigated range, i.e. between 8 and 28 atoms. The co-adsorption of H2 and O2 results in the formation of H2O, detected as a decrease in the number of adsorbed oxygen atoms with an increasing number of collisions with H2 molecules. A comparison is done with an earlier similar study of clusters of Pt. Furthermore a comparison is done with what is known for sticking and reactivity of surfaces.
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| 3. |
- Claeson, Magdalena, 1976, et al.
(författare)
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Incidence of cutaneous melanoma in Western Sweden, 1970-2007.
- 2012
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Ingår i: Melanoma research. - 1473-5636. ; 22:5, s. 392-8
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to describe the increasing incidence of cutaneous malignant melanoma (CMM) in Western Sweden during the period 1970-2007. A secondary aim was to show a geographical variation in incidence between coastal and inland areas, considering the effects of the local average duration of sunshine, and the sun exposure-related behavior in the populations. The Swedish Cancer Registry provided data on invasive melanomas during 1970-2007. Meteorological maps showed the annual average duration of sunshine during 1961-1990. A survey from 2007 with 2871 participants, carried out by the National Board of Health and Welfare, provided data on self-reported sun exposure. During the period studied, the age-standardized incidence for men in Western Sweden more than quadrupled to 31.1/100 000 inhabitants, whereas it tripled for women to 27.1/100 000. Coastal areas, including Gothenburg city, had a high average duration of sunshine (1701-1900 h of sun/year), whereas inland areas had lower average duration of sunshine (≤1700 h). The incidence of CMM was higher in coastal areas and in Gothenburg city, compared with inland areas. This may be linked to ultraviolet radiation, a consequence of the higher average duration of sunshine. The sun exposure survey showed additional factors, which possibly led to the increased incidence, for example high sun exposure on holidays abroad. The alarming increase in the incidence of CMM in Western Sweden, during the period 1970-2007, shows the need for additional primary preventive measures, for example sun protection programs targeted at populations in this area.
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| 5. |
- Sundin, Maria, 1965, et al.
(författare)
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A non -invasive method for the detection of damage and changes in the hoof capsul
- 2014
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Ingår i: 10th international equitation science conference, 6 - 9 AUGUST 2014 Vingsted. - 2245-1684. - 9788793176249
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A non-invasive method for the detection of damage and changes in the hoof capsule Maria Sundin1, Magnus Karlsteen2,Andrey Sizov3, Björn Berg4, Arne Rosén1, Henrik Otterberg5, Åsa Hinton4, Mattias Gustavsson3 1: Dept. of Physics, University of Gothenburg) 2: Department of Applied Physics, Chalmers University of Technology 3: Hot Disk AB (Sweden) 4: Ale Animal Hospital 5: Hot Disk Medical AB (Sweden) Corresponding author: maria.sundin@physics.gu.se Horses may suffer from the presence of abscesses, cracks and keratomes in the hooves. This project is a feasibility study to investigate if existing material sensors can be used as a non-invasive, non-destructive method to help veterinaries/farriers getting a better knowledge of: 1.the exact location and extent of abscesses 2.the depth and length of cracks 3.the size of keratomes. The method is based on the ability of the hoof to conduct heat Utilizing the Hot Disk Sensors and method developed in ISO22007-2, with a novel computational procedure, the variations of thermal conductivity versus depth from a surface can be measured. Sub-surface structural variations can be monitored in a non-destructive manner. Applications can be found in a range of areas. For instance, verifying homogeneity of structure versus depth. The sensor, and its holder, has approximately the shape and size of a stethoscope. It is thus an object that a farrier/veterinary can handle with ease. An area of about one square inch of the hoof is heated 1-2 degrees with a single step-wise heat pulse. The thermal depth of probing follows a relationship: ?=2??, Where d represents the thermal depth of probing (from the sensor position into the hoof), a represents the weighted average of the thermal diffusivity of the hoof (from the surface position to the position d), and t represents test time. Hence, the depth position can be determined for the different time positions. A typical time for measuring to a depth of 10 mm in a hoof capsule is 160 seconds. So far, tests in laboratory environment have established that the existing equipment works on the material that a hoof capsule consists of. Tests have been done on hoof capsules from dead horses, 3D-printed model hooves and the hooves of one live horse at a veterinary clinic. All results are reproducible. Results show the curve of the thermal conductivity versus depth changing when the heat flow reaches a place where there is an inhomogeneity in the hoof. To conclude, tests indicate the method being able to detect inhomogeneities in hooves. Further measurements will be needed to show the exact response of different problems in the hooves. LP The method offers a possible new non-invasive, non-destructive method of finding the position and extent of abscesses, cracks and other inhomogeneities in hooves. The technique is well established in other areas of material studies, and based on the analysis of thermal convection and diffusion.
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| 6. |
- Tarras-Wahlberg, Nils, 1973, et al.
(författare)
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Magnetization and Mossbauer study of partially oxidized iron cluster films deposited on HOPG
- 2014
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier BV. - 0304-8853 .- 1873-4766. ; 367, s. 40-46
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Tidskriftsartikel (refereegranskat)abstract
- Iron clusters produced in a laser vaporization source were deposited to form cluster assembled thin films with different thicknesses on highly oriented pyrolytic graphite substrates. The development of oxidation of the clusters with time, up to three years, was investigated by magnetic measurements using an alternating gradient magnetometer. Furthermore, to receive information about the oxidation states, clusters of 57Fe were studied using Mossbauer spectroscopy. The magnetic analysis shows a time evolution of the saturation magnetization, remanence, and coercivity, determined from the hysteresis curves characteristic of a progressing oxidation. The different thicknesses of the iron cluster films as well as a protective layer of vanadium influence the magnetic properties when the samples are subjected to oxidation with Lime. While the saturation magnetization and remanence decrease and reach half the initial values for almost all the samples after three years, the coercivity increases for all samples and is more substantial for the thickest sample with a vanadium protective layer. This value is three folded after three years. Furthermore, based on a core-shell model and using the saturation magnetization values we have been able to quantitatively calculate the amount of the increase of Fe-oxide as a function of time. The Mossbauer spectroscopy shows peaks corresponding to iron metal and maghemite.
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| 7. |
- Yanagihara, H., et al.
(författare)
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A molecular dynamics simulation investigation of fuel droplet in evolving ambient conditions
- 2014
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180 .- 1556-2921. ; 161:2, s. 541-550
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Tidskriftsartikel (refereegranskat)abstract
- Molecular dynamics simulations are applied to model fuel droplet surrounded by air in a spatially and temporally evolving environment. A numerical procedure is developed to include chemical reactions into molecular dynamics. The model reaction is chosen to allow investigation of the position of chemical reactions (gas phase, surface, liquid phase) and the behavior of typical products (alcohols and aldehydes). A liquid droplet at molecular scale is seen as a network of fuel molecules interacting with oxygen, nitrogen, and products of chemical fuel breakdown. A molecule is evaporating when it loosens from the network and diffuses into the air. Naturally, fuel molecules from the gas phase, oxygen and nitrogen molecules can also be adsorbed in the reverse process into the liquid phase. Thus, in the presented simulations the time and length scales of transport processes - oxygen adsorption, diffusion, and fuel evaporation are directly determined by molecular level processes and not by model constants. In addition, using ab initio calculations it is proven that the reaction barriers in liquid and gas phases are similar. (C) 2013 The Combustion Institute. Published by Elsevier Inc. All rights reserved. RAMZON B, 1989, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, V32, P1605
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