| 11. |
- Berg, Bengt-Åke, et al.
(författare)
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Samarbetets omfattning och aktörernas roll
- 2014
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Ingår i: Organiserad samverkan : svenska karteller under 1900-talet. - Möklinta : Gidlund. - 9789178448913 ; , s. 15-40
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 12. |
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| 13. |
- Berg, Mats, et al.
(författare)
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A Novel Formulation of Mometasone Furoate in Psoriasis Patients: A Multicenter, Randomized, Double-Blind Clinical Study
- 2013
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Ingår i: Advances in Therapy. - : Springer Science and Business Media LLC. - 0741-238X .- 1865-8652. ; 30:5, s. 503-516
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Tidskriftsartikel (refereegranskat)abstract
- Further formulations of mometasone furoate are needed for treatment of patients with plaque psoriasis to meet individual patient preferences. This has motivated the development of Ovixan(A (R)) (Galencia, Malmoe, Sweden), a formulation of mometasone furoate with different cosmetic properties than the commonly used formulation, Elocon(A (R)) (Merck [Schering Plough], Whitehouse Station, New Jersey, USA). This novel formulation of mometasone furoate was examined in a vasoconstrictor assay comparing its efficacy with that of Elocon. Subsequently, the new formulation was tested in a multicenter, randomized, double-blind clinical study in patients with plaque psoriasis. Healthy volunteers were included in the vasoconstrictor study. The treatments were randomly assigned to test fields on the forearms. The test fields were gently cleaned after treatment for 6 h. Skin color was measured during the following 24 h and area under the time curve was calculated. The clinical efficacy and tolerance of Ovixan was as compared to that of Elocon and their vehicles in a double-blind study in patients with plaque psoriasis. Patients with four symmetrically placed lesions on the arms or the legs were treated for 6 weeks. Primary endpoint was the change from baseline of the Total Severity Sign score for each treated lesion. The cosmetic characteristics of the two test preparations were assessed by an independent cosmetological institute. Ovixan was shown to have skin blanching potency almost identical to the vasoconstrictor potency of Elocon. Clinical equivalence of Ovixan to Elocon was demonstrated in the clinical study of the efficacy in patients with plaque psoriasis. A professional testing team clearly documented the cosmetic superiority of Ovixan as compared to Elocon. The results of the investigations show that Ovixan is equipotent to the commonly used formulation Elocon. However, the cosmetic properties are in favor of Ovixan. The effect of the cosmetic differences on patient preferences and patient adherence to prescribed treatment has to be investigated in further studies.
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| 14. |
- Berg, Sven, et al.
(författare)
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Experimental characterisation of CaCO3 powder mix for high-pressure compaction modelling
- 2010
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910 .- 1873-328X. ; 203:2, s. 198-205
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical properties of powders at high pressures are difficult to measure and therefore such data are rarely reported in open literature. Available test equipment mainly operates in the low-pressure region, 0-200 MPa. Calcite (CaCO3) is a mineral suitable for high-pressure processes, e.g. sintering of diamond compacts. It is also a very common material in the earth core and therefore of interest for geoscientists. In order to model the processes in the high-pressure region (above 1 GPa), knowledge of the mechanical properties of the powder in the entire pressure range is needed. Experimental studies have been conducted to investigate the pressure-density relationship of a CaCO3 powder and also to correlate the relative density to elastic and strength properties using experimental results. Further, a methodology has been introduced to provide a foundation for an elastic-plastic constitutive model. The mechanical behaviour of a CaCO3 powder mix has been investigated using the Brazilian disc test, uniaxial compression testing and closed die experiments. The experiments showed increasing elastic modulus and strength with increasing density. An empirical expression of the dependence of the bulk modulus on density has also been introduced.
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| 15. |
- Berg, Sven, et al.
(författare)
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Experimental characterization of CaCO3powder for use in compressible gaskets up to ultra-high pressure
- 2012
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910 .- 1873-328X. ; 215-216, s. 124-131
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate the compaction properties for a CaCO3 powder mix up to ultra-high pressure (10GPa) and how these properties affect the gasket behaviour. Different parameters of the powder are investigated, i.e. initial density and internal moisture. A set-up, supporting the outer diameter of the compact, commonly used for gaskets in the belt apparatus was also investigated. The experimental results are in terms of pressure instrumentation in the Bridgman anvil apparatus together with load–displacement curves of the powder compacts. The instrumentation is done so that it can be used to calibrate constitutive models.
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| 16. |
- Berg, Sven, et al.
(författare)
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Frictional behaviour of CaCO3 powder compacts
- 2012
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910 .- 1873-328X. ; 228, s. 429-434
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Tidskriftsartikel (refereegranskat)abstract
- During powder compaction processes friction has an influence on the final shape and properties of components. It is therefore important to understand how the friction influences the compaction process. Since detailed friction measurements of the powder compact-tool interface are rare, simulation models of the powder compaction process often involve a more accurate description of the frictional behaviour. This limits the accuracy of the simulated results. More accurate numerical models can give improved results, especially in regards to the evolution of density and its distribution within the powder compacts.This study is as a step towards more advanced friction models for powder compaction simulations. A universal tribometer has been used to investigate the frictional behaviour of contact interfaces between a carbide counter surface and CaCO3 powder compacts with different densities. Both static and dynamic frictional properties were measured in a variety of conditions to build a fundamental foundation for friction modelling in powder compaction simulations.The results show that increasing the powder compact density decreases the dynamic friction coefficient but that the static friction coefficient remains fairly constant. The measured friction coefficient can be used to improve the simulation of a powder compact process. Also investigated is the change in friction coefficient that occurs in the compaction process when the surfaces are worn such that loose powder appears in the interface between the tool and the powder compact. This behaviour is important to take into account to accurately describe the compaction process.
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| 17. |
- Berg, Sven, et al.
(författare)
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High pressure characterization and modelling of CaCO3 powder mix in the Bridgman anvil apparatus
- 2012
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Ingår i: High Pressure Research. - : Informa UK Limited. - 0895-7959 .- 1477-2299. ; 32:4, s. 490-508
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Tidskriftsartikel (refereegranskat)abstract
- For investigating high pressure sintering processes, numerical models can be used. This will demand material models which give realistic mechanical response throughout the whole parameter space of the actual process. As the pressures become higher, the material density approaches its full theoretical value and the elastic part of the material properties becomes increasingly important. In this investigation, Poisson's ratio was determined using ultrasonic pulse-echo measurements. A new elastic model and an improved plasticity model were implemented into a user-defined material subroutine in a finite element (FE) code. To experimentally investigate the load displacement response and pressure distribution in powder compacts during pressing, a pressure instrumented Bridgman anvil apparatus was used. Validation of the FE model was conducted against experimental data from pressing experiments using two different start densities. The results show that the simulation model is indeed capable of reproducing load–thickness curves and pressure profiles reasonable close to the experimental curves.
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| 18. |
- Berg, Sven, et al.
(författare)
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High-pressure compaction modelling of calcite (CaCO3) powder compact
- 2011
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910 .- 1873-328X. ; 206:3, s. 259-268
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Tidskriftsartikel (refereegranskat)abstract
- Numerical simulation of manufacturing processes with working conditions at high pressure (above 1 GPa) requires constitutive data of the powder for the whole range of pressure and density. Most of the test apparatuses commonly used to obtain such data is only working in the lower pressure regions. Because of the absence of high-pressure data, many parameters have to be guessed or extrapolated. A material used in high-pressure applications is Calcite (CaCO3). The material can be used as an insulator in high-pressure capsules it is also a common material in the earth core. An apparatus often used to generate high pressure during compaction is the Bridgman anvil apparatus. In this work experimental tests with a Bridgman anvil set-up using Calcite powder discs with different thicknesses were done. A nonlinear elastic-plastic cap model was developed to model the behaviour of powder material from low pressure and loose state to high pressure and solid state. The constitutive model was implemented in a finite element code. The constitutive data were identified by optimization of experimental data. Validation was done by numerically reproduce the mechanical behaviour of uni-axially pressing Calcite to different pressure (up to 5 GPa) including unloading. The load-displacement curves, density distribution and the surface displacement were measured and compared to the finite element results. The results of the compaction simulations agree reasonably well with the experimental results.
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| 19. |
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| 20. |
- Berg, Åke, et al.
(författare)
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Assessing agri-environmental schemes for semi-natural grasslands during a 5-year period: can we see positive effects for vascular plants and pollinators?
- 2019
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Ingår i: Biodiversity and Conservation. - : Springer Science and Business Media LLC. - 0960-3115 .- 1572-9710. ; 28, s. 3989-4005
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Tidskriftsartikel (refereegranskat)abstract
- An important function of agri-environmental schemes (AES) is to change management of pastures to better conserve biodiversity. However, the effects of most AES on biodiversity are poorly understood, especially when it comes to effects of AES management over time. The main aim of this study is to investigate if the species richness and abundance of grassland specialists of vascular plants and two important insect pollinator groups (bumblebees and butterflies) differ over time (5 years) in pastures with AES management (two value levels; general values and special values) and pastures without AES management. We also investigate if local vegetation characteristics and landscape composition relate to species richness in semi-natural grasslands. Using data from more than 400 sites we found that species richness of vascular plants (grassland specialists) was higher in pastures with AES management (for special and general values) compared to those without AES, which implies that these schemes do have value of the conservation of plant diversity. However, species richness and abundance of butterflies (grassland specialists) and bumblebees (all species) did not differ significantly among the three AES categories. We found no evidence that the type of AES management caused any changes in species richness of plants, butterflies or bumblebees during the 5 year period of our investigation. It appears that AES management that encourages uniform and minimum levels of grazing can have both positive and negative effects on biodiversity. For example, pollinators may benefit from a lower grazing intensity that could increase flower richness and heterogeneity in vegetation height. However, low grazing intensity may lead to increased cover of trees and shrubs, which can have negative effects for both insect pollinators and vascular plants. The effects of landscape composition were weak and only species richness of bumble bees were associated with landscape composition. Designing management regimes to maintain suitably heterogeneous vegetation layer, and continued long-term monitoring of biodiversity will be critical for safeguarding culturally and functionally important semi-natural grasslands.
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