| 1. |
- Byström, Johan, et al.
(författare)
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Bounds and numerical results for the homogenized degenerated p-Poisson equation
- 2004
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Ingår i: Applications of Mathematics. - 0862-7940 .- 1572-9109. ; 49:2, s. 111-122
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we derive upper and lower bounds on the homogenized energy density functional corresponding to degenerated p-Poisson equations. Moreover, we give some non-trivial examples where the bounds are tight and thus can be used as good approximations of the homogenized properties. We even present some cases where the bounds coincide and also compare them with some numerical results.
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| 2. |
- Byström, Johan, et al.
(författare)
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Reiterated homogenization of degenerate nonlinear elliptic equations
- 2002
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Ingår i: Chinese Annals of Mathematics. Series B. - 0252-9599 .- 1860-6261. ; 23:3, s. 325-334
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Tidskriftsartikel (refereegranskat)abstract
- The authors study homogenization of some nonlinear partial differential equations of the form _ div (a (hx, h2 x, Duh)) = f , where a is periodic in the rst two arguments and monotone in the third. In particular the case where a satis es degenerated structure conditions is studied. It is proved that uh converges weakly in W0 1,1 (Ω) to the unique solution of a limit problem as h → ∞ . Moreover, explicit expressions for the limit problem are obtained.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Engström, Björn, et al.
(författare)
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Anchorage and bond in high strenght concrete
- 2000
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Ingår i: Bond of reinforcement in concrete. - Lausanne : International Federation for Structural Concrete / Task Group Bond Models. - 2883940509 ; , s. 99-156
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Engström, Jonas
(författare)
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Some contributions to homogenization theory
- 2002
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is devoted to homogenization theory and consists of an introduction and five papers. The introduction gives an elementary presentation of the basic ideas in homogenization theory, serves as an overview of the field and points out where the results of this thesis fit in. The first paper deals with reiterated homogenization of degenerate nonlinear monotone operators. In the second paper bounds and some numerical results for the homogenized degenerated p-Poisson equation are given. The third and fourth paper deal with some numerical aspects connected to homogenization theory. Finally, in the fifth paper a short introduction to homogenization of random monotone operators is given.
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| 8. |
- Engström, V., et al.
(författare)
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The effect of seed size on the growth of silicalite-1 films on gold surfaces
- 2000
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Ingår i: Microporous and Mesoporous Materials. - 1387-1811 .- 1873-3093. ; 38:1, s. 51-60
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Tidskriftsartikel (refereegranskat)abstract
- Silicalite-1 films grown on gold surfaces seeded with colloidal crystals with a size of 60, 165 and 320 nm were investigated by reflection–absorption infrared spectroscopy, scanning electron microscopy and X-ray diffraction in order to follow up the formation of nano-scale defects and to determine the optimal synthesis conditions for preparation of silicalite-1 films with a low concentration of defects. Using 60-nm-sized colloidal crystals, the seeding method was capable of producing silicalite-1 films with low concentrations of defects and with thicknesses ranging from 100 to 300 nm, which are predominantly oriented with the a-axis perpendicular to the surface. Hydrothermal treatment times of the 60-nm-seeded surfaces longer than 36 h as well as the seeding with 165 or 320 nm colloidal crystals substantially enhanced the formation of defects in the films.
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| 9. |
- Hedblad, Bo, et al.
(författare)
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Incidence of cardiovascular disease, cancer and death in postmenopausal women affirming use of hormone replacement therapy.
- 2002
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Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1651-1905 .- 1403-4948. ; 30:1, s. 12-19
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Tidskriftsartikel (refereegranskat)abstract
- AIM: The goal of this study was to evaluate the incidence of myocardial infarction, cancer and death in relation to use of hormone replacement therapy (HRT). METHODS: Nine years' follow up of an urban cohort of peri-/postmenopausal women was undertaken. Local and national registers were used for retrieval of events. RESULTS: The incidence of myocardial infarction per 1.000 person-years in users and non-users was 0.61 (5/962) and 2.20 (92/4759) respectively, adjusted relative risk (RR) 0.37; 95% confidence interval 0.15-0.90. Rates of mortality from cardiovascular disease and cancer were 0.36 and 1.10, p= 0.058, and 2.60 and 2.09, p=0.360 respectively. In terms of all-cause mortality the adjusted RR was 1.02; 0.69-1.52, incidence of cancer 1.28; 1.01-1.64, breast cancer 1.52; 1.01-2.28 and endometrial cancer 3.61; 1.54-8.46. CONCLUSIONS: Women affirming use of HRT had a lower incidence of myocardial infarction. Further studies are needed to assess whether the absence of effect on total mortality may be accounted for by an increased cancer risk.
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| 10. |
- Herbertsson, Jonas, et al.
(författare)
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Reconfigurable aircraft assembly : using industrial robots and new tooling to meet future production scenarios
- 2002
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Ingår i: Proceedings of the 33rd ISR (International Symposium on Robotics).
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Konferensbidrag (refereegranskat)abstract
- This paper presents the development of a new concept for aircraft airframe assembly tooling. While conventional aircraft assembly tooling relics on rigid steel frames this novel approach can be re-con figured for different products by the help of an accurate laser tracker guided industrial robot. Through this, aircraft manufacturers can better cope with an increased number of variants and smaller volumes which will increase the already high tooling costs. So far in the project a tooling concept has been conceptually designed and economically evaluated. The early technical results of the concepntal work indicate that the concept will work provided that enough mechanical stiffness can be obtained. The economical analysis shows that despite a much higher investment cost, a reconfigurable tool can be economical if it will replace 4-5 conventional tools. In certain future production scenarios reconfigurable tooling can play a very important role to keep the tooling costs down.
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