| 11. |
- Berbyuk, Viktor, 1953
(författare)
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Energy-optimal control of human leg in swing phase
- 1995
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Ingår i: Biomechanics Seminar. - 1100-2247. ; 9, s. 32-49
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Konferensbidrag (refereegranskat)abstract
- The mathematical model and efficient algorithm for designing the energy-optimal controlled processes of a human leg in the swing phase are proposed. This algorithm is based on special conversion of the optimal control problem for nonlinear dynamical system modeled a human leg into a standard nonlinear programming problem. The objective function for the optimization algorithm is the integral over swing phase's time from the sum of the mechanical power absolute values for all controlling stimuli. A number of the energy-optimal controlled processes of a human leg under different boundary conditions and restrictions on phase coordinates have been obtained. The kinematical and dynamical characteristics of obtained optimal controlled processes are compared with respective characteristics of a human leg's swing phase during normal gait.
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| 12. |
- Berglund, Johan C, 1978, et al.
(författare)
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Measuring strategies for smooth tool steel surfaces
- 2008
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Ingår i: Proceedings. - Aachen : Shaker Verlag. - 1610-4773. - 9783832269128 - 3832269126 ; , s. 110-119
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Comparisons between different measuring strategies were made on three types of smooth tool steel surfaces. Three replica materials were tested to study possibilities within replication techniques. An optical interferometer as well as a mechanical stylus was used to evaluate the surfaces. The results showed that the tested replica materials generated good representations of both the form and the surface roughness (Sq > 300 nm). The evaluated surfaces were quite homogeneous, thus, few measurements are needed to get representative results. However, it was found that caution must be taken regarding manually polished surfaces which can be less homogenous and therefore require more measurements to get representative results.
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| 13. |
- Bin, Ma, et al.
(författare)
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Dielectric Properties and Resistance to Corona and Ozone of Epoxy Compositions Filled with Micro- and Nano-fillers
- 2009
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Ingår i: Annual Report - Conference on Electrical Insulation and Dielectric Phenomena. ; , s. -380
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Konferensbidrag (refereegranskat)abstract
- This paper describes activities aiming to evaluate and compare the resistance to a prolonged corona and ozone exposure for a range of epoxy based compositions filled with micro- and nano-fillers of silica at different proportions. It has been earlier shown for this system that substitution of 5 wt% of micro-filler by nano-filler slightly improved mechanical properties, yielding an increase in Young's modulus, tensile strength and elongation at break. At the same time, the toughness of the systems decreased with the addition of nano-fillers indicating a poor particle-matrix interaction, which was in accordance with the prior art claiming that this interaction is weaker in case of SiO 2 nano-particles, as for example compared to Al 2O 3 nano-particles. For the exposure to corona and ozone a methodology employing a multiple-needle electrode system was used, as recommended by CIGRE working group WG D1.14. Measurements of surface resistivity, bulk resistivity as well as dielectric response (DR) at broad frequency range (10 -4-10 3 Hz) were performed on new samples of the investigated compositions and after each of two sequences of the corona-ozone treatment, lasting 100hours each. It was found that the long-term corona-ozone exposure had obvious effect on surface resistivity for all the compositions investigated and the contents of the micro- and nano-fillers played a significant role in the observed changes. On the other hand, bulk resisitivity, dielectric permittivity as well as dissipation factor, all being the properties of material bulk, did not exhibit high sensitivity to the exposure.
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| 14. |
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| 15. |
- Blanck, Hans, 1950, et al.
(författare)
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A retrospective analysis of contamination and periphyton PICT patterns for the antifoulant irgarol 1051, around a small marina on the Swedish west coast
- 2009
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Ingår i: Marine Pollution Bulletin. - : Elsevier BV. - 0025-326X .- 1879-3363. ; 58, s. 230-237
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Tidskriftsartikel (refereegranskat)abstract
- Irgarol is a triazine photosystem II (PSII) inhibitor that has been used in Sweden as an antifouling ingredient since the 1990s. Early microcosm studies indicated that periphyton was sensitive to irgarol at concentrations regularly found in harbours and marinas. However, field studies of irgarol effects on the Swedish west coast in 1994, using the pollution-induced community tolerance (PICT) approach, failed to detect any effects of the toxicant in the field. A PICT study involves sampling of replicate communities in a gradient of contamination, and a comparison of their community tolerance levels, with an increase being an indication that sensitive species have been eliminated and replaced by more tolerant ones. Typically, short-term assays are used to quantify the community tolerance levels. Later PICT studies in the same area over a 10 year period demonstrate that irgarol tolerance levels have increased, although the contamination pattern has been stable. Our results support the hypothesis that that the PICT potential was low initially, due to a small differential sensitivity between the community members, and that a persistent selection pressure was required to favour and enrich irgarol-tolerant species or genotypes. © 2008 Elsevier Ltd. All rights reserved.
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| 16. |
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| 17. |
- Boman, Christoffer, 1970-, et al.
(författare)
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Effects of increased small-scale biomass pellet combustion on ambient air quality in residential areas : A parametric dispersion modeling study
- 2003
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Ingår i: Biomass and Bioenergy. - : Elsevier. - 0961-9534 .- 1873-2909. ; 24:6, s. 465-474
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Tidskriftsartikel (refereegranskat)abstract
- Sweden's goals of contemporaneously reducing CO2 emissions and phasing out nuclear power will require a maximum utilization of biomass fuels. This would imply a significant shift from electricity and fuel oil to biomass generated heat, but must also be accomplished without a deterioration of the local air quality. The most suitable energy carrier seems to be pelletized biomass fuels with their associated low emissions and considerable residential conversion potential. Using an underlying statistical design, a parametric dispersion modeling study was performed to estimate and illustrate the combined effects of source-specific, meteorological and modeling variables on the ambient air quality in a typical residential area for different conversion scenarios. The work nicely illustrated the benefits of combining statistical designs with model calculations. It further showed that the concentration of combustion related ambient THC was strongly related to conditions affecting the source strength, but only weakly to the dispersion conditions and model variables. Time of year (summer or winter); specific emission performance; extent of conversion from electricity; conversion from wood log combustion; and specific efficiency of the pellet appliances showed significant effects in descending order. The effects of local settings and model variables were relatively small, making the results more generally applicable. To accomplish the desired conversion to renewable energy in an ecologically and sustainable way, the emissions would have to be reduced to a maximum advisable limit of (given as CH4). Further, the results showed the potential positive influence by conversion from wood log to low emission pellet combustion.
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| 18. |
- Cassens, U., et al.
(författare)
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Viral modulation of cell death by inhibition of caspases
- 2003
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Ingår i: Archivum Immunologiae et Therapiae Experimentalis. - 0004-069X .- 1661-4917. ; 51:1, s. 19-27
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Forskningsöversikt (refereegranskat)abstract
- Caspases are key effectors of the apoptotic process. Some of them play important roles in the immune system, being involved in the proteolytic maturation of the key cytokines, including interleukin 1beta (IL-1beta) and IL-18. The latter directs the production of interferon gamma (IFN-gamma). Among pathogens, particularly viruses express various modulators of caspases that inhibit their activity by direct binding. By evading the apoptotic process, viruses can better control their production in the infected cell and avoid the attack of the immune system. Targeting the maturation of the key cytokines involved in the initiation of (antiviral) immune response helps to avoid recognition and eradication by the immune system. The three main classes of caspase inhibitors frequently found among viruses include serine proteinase inhibitors (serpins: CrmA/SPI-2), viral IAPs (vIAPs) and p35. Their molecular mechanisms of action, structures and overall influence on cellular physiology are discussed in the review below.
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| 19. |
- Dal, Lovisa, et al.
(författare)
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Conservation of the Warship Vasa : the treatment and the present problems
- 2002
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Ingår i: International Congress on the Conservation and Restoration for Archaeological Objects : Preprints - Preprints. ; , s. 29-38
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In 1628, the Swedish Royal warship Vasa capsized on her maiden voyage. She was salvaged in 1961 and became the first major object to be treated with polyethyleneglycol, PEG. The extensive conservation treatment lasted for almost 30 years. Today a new problem has risen as sulphuric acid is formed in the wood, causing acid hydrolysis of the cellulose.
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| 20. |
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