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- Lökk, Johan, et al.
(författare)
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Controversies around vitamin B12 in Sweden. : Attitudes and values behind clinical decision-making in primary health care 1996
- 1997
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Ingår i: Hematology. - 1024-5332 .- 1607-8454. ; 2:4, s. 341-350
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Tidskriftsartikel (refereegranskat)abstract
- Over a five-year period, 1991-1995, the vitamin B12 market in Sweden increased three-fold, from approximatelyy 2 million U.S. dollars to approximately 6 million U.S. dollars. Most prescriptions, approximately 60%, originated from primary health care. The attitudes, values and knowledge of the family physicians/general practitioners were elucidated by a questionnaire study with visuo-analogue opinion scales, evaluating 24 basic statements on problems associated with the management of vitamin B12 deficiency. The questionnaire was sent to a representative sample of 506 family physicians/general practitioners. Response rate was 74%. Dropout analysis supported the view that responders provided a representative sample of Swedish FP/GPs. Analysis of the answers was compatible with the hypothesis that the mentioned increase in Swedish B12 market reflected increased awareness in primary health care about the biochemical, pathophysiological and social problems associated with vitamin B12 deficiency.
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| 5. |
- Wänstrand, Olle, et al.
(författare)
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An experimental method for evaluation of the load carrying capacity of coated aluminium : the influence of coating stiffness, hardness and thickness
- 2000
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Ingår i: Surface & Coatings Technology. - 0257-8972 .- 1879-3347. ; 127:2-3, s. 107-113
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Tidskriftsartikel (refereegranskat)abstract
- If a brittle ceramic PVD coating is applied to a soft and compliant material such as aluminium, it might crack when the component is taken into use, i.e. when it is loaded. This means that the load-carryingcapacity of the soft Al substrate has to be improved if a PVD coating should be applied successfully. One solution is to introduce a relatively thick intermediate load-carrying layer between the soft substrate and the thin ceramic PVD coating. This paper presents a new experimental test method to find the load-carrying layer thickness required to protect a soft substrate from plastic deformation. The method is evaluated, but also used to investigate different load-carrying layers on aluminium. In the experiment, rigid cemented carbide balls were used to indent aluminiumcoated with, compared with PVD coatings, relatively thick (50–150 μm) foils. The foils were firmly attached to the aluminium substrates using a fusible and strong adhesive. After indentation the foil/coating was detached and the amount of plastic deformation on the substrate surface was determined by measuring the depth of the residual indent. The influence of foil thickness, stiffness and hardness on the resistance to plastic substrate deformation was studied. It was found that the technique of gluing foils on Al well simulates the load-carrying properties of a traditionally deposited layer. The indentation experiments also showed that the load-carryingcapacity of the coatedaluminium increases with the thickness of the foil and the elastic modulus of the foil. No significant influence of the foil/coating hardness on the load-carryingcapacity could be seen.
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| 6. |
- Wänstrand, Olle, et al.
(författare)
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Design of low weight components : a theoretical approach
- 2002
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Ingår i: Surface Engineering. - : Informa UK Limited. - 0267-0844 .- 1743-2944. ; 18:2, s. 93-97
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Tidskriftsartikel (refereegranskat)abstract
- The commercially available software package Elastica has been used to calculate the von Mises stresses in steel as well as in titanium nitride (TiN) and nickel coated aluminium subjected to spherical indentation. Uncoated steel of three different yield strengths was used as reference material, and indenters of different radii were utilised. The critical loads for plastic deformation arrived at were then applied to an Al alloy coated with 5 ? m TiN, and any yield was detected. In cases where the TiN coating could not protect the Al alloy from plastic flow, the required thickness of an intermediate nickel layer was calculated. It was found that with sharp indenters, it is possible to obtain the same critical load for onset of plastic deformation for TiN coated aluminium as for uncoated hardened steels. When the radius of the indenter is large, however, this is not possible owing to the limited thickness of the TiN coating. With the introduction of an intermediate load carrying nickel layer between the aluminium base material and the thin TiN coating the critical load for onset of plastic deformation can be increased.
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| 7. |
- Wänstrand, Olle, et al.
(författare)
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Load-carrying capacity of Ni-plated media in spherical indentation : experimental and theoretical results
- 2002
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Ingår i: Surface Engineering. - : Informa UK Limited. - 0267-0844 .- 1743-2944. ; 18:2, s. 98-104
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Tidskriftsartikel (refereegranskat)abstract
- Spherical indentation ex periments have been performed on aluminium and steel specimens. Some of the specimens were layered with electroplated nickel and all were surface coated with thin vapour deposited WC/C. The experimental results were compared with simulations made with the commercially available Elastica software package. The aim of the study was to investigate how an intermediate load carrying layer between a soft and compliant base material and a thin brittle coating can improve the resistance to plastic deformation. This study shows that thick and dense electroplated nickel layers, which give good adhesion both to base materials (aluminium and steel) and to PVD coatings (WC/C), can be produced and used as load carrying layers. As expected, it was found that an intermediate load carrying layer of sufficient thickness and suitable mechanical properties improves the load carrying capacity of soft and compliant base materials. It was also found that with a stiff layer on a more compliant base material, an intermediate layer that was too thin would decrease the load carrying capacity as compared with the homogeneous base material case. Finally, although not including plastic deformation, the analytical elastic calculations proved to be valuable for the interpretation of the experimental results.
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| 8. |
- Wänstrand, Olle, et al.
(författare)
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Mechanical and tribological properties of vapour deposited low friction coatings on Ni plated substrates
- 2000
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Ingår i: Tribology International. - 0301-679X .- 1879-2464. ; 33:10, s. 737-742
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Tidskriftsartikel (refereegranskat)abstract
- Soft steel and aluminium substrates with load-carrying layers of electroplated nickel were coated with commercially available lowfrictionvapourdepositedcoatings. The mechanical and tribologicalproperties of the coating and substrate composites were evaluated with special emphasis on the influence of the nickel layer. Two different thicknesses of the intermediate load-carrying nickel layer were tested. The samples were evaluated regarding friction and sliding wear, abrasive wear, hardness and elastic modulus, morphology and coating thickness and adhesion between substrate and coating. It was found that all the evaluated lowfrictioncoatings were possible to be successfully deposited on the intermediate nickel layer. A relatively thick intermediate nickel layer is a promising candidate for improvement of the load-carrying capacity
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