| 1. |
- Almqvist, Torbjörn, et al.
(author)
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THD analysis of tilting pad thrust bearings : comparison between theory and experiments
- 2000
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In: Journal of tribology. - : ASME International. - 0742-4787 .- 1528-8897. ; 122:2, s. 412-417
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Journal article (peer-reviewed)abstract
- The objective of the present research is to verify a THD model of hydrodynamic thrust bearings. The developed model of a pivoted pad bearing, which can tilt both radially and circumferentially, allows for three-dimensional temperature distribution in the oil film and in the pad, as well as two-dimensional temperature variation in the runner. Viscosity and density are treated as functions of both temperature and pressure. Experiments have been performed on a test rig, containing two identical equalizing pivoted pad thrust bearings. Power loss, runner temperature, and pressure profiles as a function of load and rotational speed are compared for both theoretical and experimental investigations. Fairly good agreement has been found when the oil inlet temperature and heat transfer coefficients have been estimated in order to get the same runner temperature in both theory and experiment.
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| 2. |
- Larsson, Lennart, et al.
(author)
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Mellanlagring av asfalt : delrapport 4: utlakning från vägbeläggningsmaterial innehållande stenkolstjära
- 2000
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Reports (other academic/artistic)abstract
- Föreliggande studie omfattar kolonnlakning av valda organiska ämnen från ett äldre vägbeläggningsmaterial av typen tjärindränkt grusmaterial, innehållande en totalhalt för gruppen 16-PAH av 5,3 g/kg. Sammantaget visar den nu genomförda undersökningen att de utlakade medelhalterna av summa cancerogena PAH är mycket höga och avsevärt överstiger föreslagna riktvärden för dessa PAH i grundvatten vid bensinstationer inom hela det undersökta L/S-intervallet (0–2,0). Medelhalten av summa övriga PAH överstiger föreslagna riktvärden i grundvatten vid bensinstationer i L/S-intervallet upp till cirka L/S 0,8, varefter denna halt minskar till under nämnda riktvärde i L/S-intervallet cirka 0,8–2,0. Generellt erhölls mycket större ackumulerade utlakade mängder av både summa cancerogena PAH och summa övriga PAH från det nu undersökta tjärinnehållande beläggningsmaterialet än från tidigare undersökta beläggningsmaterial. Vidare uppvisar de tre första (upp till ca L/S 0,8) av de fyra analyserade lakvattnen mycket hög akuttoxicitet om vattnen jämförs med grundvatten och mycket stor påverkan av punktkälla om de likställs med ytvatten. De högsta medelhalter som lakades ut av acetofenon låg i samma storleksnivå som tidigare maximalt har analyserats i lakvatten från beläggningsmaterial, men låg ändå under ett tidigare angivet utländskt gränsvärde i ytfiskevatten. Utlakade medelhalter av EGOM kan anses vara låga och förelåg i den under delen av det intervall som uppvisats från tidigare lakade beläggningsmaterial. Bensen, toluen, etylbensen, xylen och fenol låg alla under respektive detektionsgräns.
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| 3. |
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| 4. |
- Nordin, M., et al.
(author)
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Residual stress formation in multilayered TiN/TaNx coatings during reactive magnetron sputter deposition
- 2000
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In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : American Vacuum Society. - 0734-2101 .- 1520-8559. ; 18:6, s. 2884-2889
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Journal article (peer-reviewed)abstract
- Multilayered physical vapor deposited TiN/TaNx coatings were deposited on cemented carbide substrates using a dual target magnetron sputtering system. The coatings were investigated with respect to the influence of nitrogen partial pressure during deposition on the residual stress developed in the coatings. Furthermore, the fracture strength of the material, i.e., the magnitude of the tensile stress that the coating can support without cracking, was evaluated. It was found that, by increasing the nitrogen partial pressure, it is possible to change the stress from compressive to tensile. The highest tensile stress was about 3.6 GPa. Despite this high stress, the coating displayed no cracking. This implies that it is possible to grow TiN/TaNx multilayered coatings with high tensile fracture strength using dual magnetron sputtering and a high deposition temperature (about 680 °C).
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| 5. |
- Whiss, Per A., 1966-, et al.
(author)
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Acute Effects of Nicotine Infusion on Platelets in Nicotine Users with Normal and Impaired Renal Function
- 2000
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In: Toxicology and Applied Pharmacology. - : Elsevier BV. - 0041-008X .- 1096-0333. ; 163:2, s. 95-104
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Journal article (peer-reviewed)abstract
- The role of platelets in cardiovascular disease associated with smoking is becoming more established, but the effects of nicotine on platelets are unclear. Nicotine therapy is used for smoking cessation in both health and disease. Consequently, the effects of nicotine on platelets are of particular significance in disorders such as renal disease, which is associated with defective platelet function, increased cardiovascular morbidity, and altered nicotine metabolism. Thus, the aim of the present study was to investigate the acute effects of nicotine infusion (NI) on platelets in seven healthy subjects (HS) and seven patients with renal failure (RF). All subjects were nicotine users and had refrained from using nicotine for 36 h before NI. Blood was collected before, immediately after, and 2 h after NI. The plasma concentrations of nicotine and its main metabolite cotinine were determined by gas chromatography. Platelet responsiveness was assessed by aggregometry and flow cytometry in whole blood (P-selectin surface expression, fibrinogen- and von Willebrand factor-binding), P-selectin expression in isolated platelets, and immunoassays of platelet release (β-thromboglobulin, platelet factor 4, and soluble P-selectin) and nitric oxide (NO) products. The plasma levels of cotinine, but not nicotine, were significantly higher in RF compared to HS at all time points. In both groups, collagen-induced platelet aggregation was restrained immediately after NI, when the plasma concentration of nicotine was maximal, and was restored after 2 h. Two hours after NI, activation-dependent P-selectin surface expression in isolated platelets increased in both groups. This increased platelet responsiveness occurred simultaneously with a significant increase of plasma cotinine and a decrease of NO products. Thus, the present study suggests that nicotine, directly or through some secondary mechanism or metabolite, only slightly potentiates some of the platelet responses. Renal failure appears not to influence the effects of nicotine on platelets.
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