| 1. |
- Hedenrud, Tove, 1967, et al.
(författare)
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"Psychiatry is not a science like others" - a focus group study on psychotropic prescribing in primary care.
- 2013
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Ingår i: BMC family practice. - : Springer Science and Business Media LLC. - 1471-2296. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Psychotropic drug prescribing is problematic and knowledge of factors affecting the initiation and maintenance of such prescribing is incomplete. Such knowledge could provide a basis for the design of interventions to change prescribing patterns for psychotropics. The aim of this study was to explore the views of general practitioners (GPs), GP interns, and heads of primary care units on factors affecting the prescribing of psychotropic drugs in primary care. Methods: We performed four focus group discussions in Gothenburg, Sweden, with a total of 21 participants (GPs, GP interns, and heads of primary care units). The focus group discussions were transcribed verbatim and analyzed using manifest content analysis. Results: Three different themes emerged from the focus group discussions. The first theme Seeking care for symptoms, reflects the participants’ understanding of why patients approach primary care and comprised categories such as knowledge, attitudes, and society and the media. The second theme, Lacking a framework, resources, and treatment alternatives, which reflects the conditions for the physician-patient interaction, comprised categories such as economy and resources, technology, and organizational aspects. The third theme, Restricting or maintaining prescriptions, with the subthemes Individual factors and External influences, reflects the physicians’ internal decision making and comprised categories such as emotions, knowledge, and pharmaceutical industry. Conclusion: The results of the present study indicate that a variety of factors may affect the prescribing of psychotropic medications in primary care. Many factors were related to characteristics of the patient, the physician or their interaction, rather than the patients’ medical needs per se. The results may be useful for interventions to improve psychotropic prescribing in primary care.
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| 2. |
- Huč, Sabina, 1987-, et al.
(författare)
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Coupled two-dimensional modeling of viscoelastic creep of wood
- 2018
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Ingår i: Wood Science and Technology. - : Springer. - 0043-7719 .- 1432-5225. ; 52:1, s. 29-43
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Tidskriftsartikel (refereegranskat)abstract
- Three coupled two-dimensional viscoelastic creep models for orthotropic material are analyzed. The models of different complexity are mathematically formulated and implemented in a finite element software. Required viscoelastic material parameters are determined by calibration procedure, where numerical results are compared against experimentally obtained viscoelastic strains caused by tensile or shear loading. Finally, a comparison method is used to evaluate the accuracy of strain predictions of each particular model. The analysis shows that all the models are able to accurately predict viscoelastic creep simultaneously in two perpendicular directions for various periods of time and wood species. Calculated numerical values of the viscoelastic material parameters suitable for the three models and wood species, i.e., Douglas fir (Pseudotsuga menziesii), Norway spruce (Picea abies), Japanese cypress (Chamaecyparis obtusa), and European beech (Fagus sylvatica L.), under constant tensile loading are also given.
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| 3. |
- Huc, Sabina, et al.
(författare)
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Hygro-mechanical analysis of wood subjected to constant mechanical load and varying relative humidity
- 2018
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Ingår i: Holzforschung. - : WALTER DE GRUYTER GMBH. - 0018-3830 .- 1437-434X. ; 72:10, s. 863-870
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Tidskriftsartikel (refereegranskat)abstract
- A hygro-mechanical (H-M) analysis of a wooden specimen sustaining a mechanical load while subjected to varying relative humidity was performed to predict the long-term rheological behavior of wood. The numerical analysis was based on the experimental results of total strains, monitored in two orthotropic material directions on oak wood specimens under constant uniaxial compression and with moisture content (MC) variation. For the moisture analysis, a multi-Fickian moisture transport model (MFMTM) was used to obtain temporal and spatial MC fields, which were the input data in the mechanical analysis. The presented mechanical model assumed a decomposition of the total strains into the elastic, viscoelastic and mechanosorptive strains and the strains due to shrinkage and swelling. The moisture and mechanical analyses required material parameters, which were taken from the literature or were empirically obtained by a fitting procedure. The performed H-M analysis gave accurate numerical predictions of the experimentally obtained total strains in two orthotropic directions simultaneously. Thus, the analysis developed has a high potential for predicting the long-term rheological behavior of timber structures, assuming that the material parameters are determined previously, based on specific, extensive, multidimensional experimental analyses.
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| 4. |
- Huc, Sabina, et al.
(författare)
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Influence of grain direction on the time-dependent behavior of wood analyzed by a 3D rheological model : A mathematical consideration
- 2018
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Ingår i: Holzforschung. - : WALTER DE GRUYTER GMBH. - 0018-3830 .- 1437-434X. ; 72:10, s. 889-897
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Tidskriftsartikel (refereegranskat)abstract
- A three-dimensional (3D) rheological model for an orthotropic material subjected to sustained load or deformation under constant climate has been mathematically formulated. The elastic and viscoelastic compliance matrices are symmetric, where the mathematical derivation of the latter is shown. The model is linear and requires constant numerical values for the elastic and viscoelastic material parameters. The model's ability to predict the natural time-dependent response in three material directions simultaneously is demonstrated on a Douglas fir (Pseudotsuga menziesii) specimen subjected to a constant uniaxial tensile load. The material extends in a longitudinal direction and contracts in the transverse directions with time. The required material parameters are taken from the literature when possible, otherwise they are assumed. Furthermore, the influence of misalignment between the directions of observation and wood material directions on induced time-dependent strains is analyzed. The analyses show that the misalignment has a large effect on the material behavior. In some cases, the specimen under constant uniaxial tension even extends in the perpendicular transverse direction with time. The obtained results clearly demonstrate the high importance of considering the alignment of material directions precisely in order to be able to interpret the time-dependent behavior of wood correctly.
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| 5. |
- Huč, Sabina, 1987-, et al.
(författare)
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Numerical analysis of moisture-induced strains and stresses in glued-laminated timber
- 2020
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Ingår i: Holzforschung. - : Walter de Gruyter. - 0018-3830 .- 1437-434X. ; 74:5, s. 445-457
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Tidskriftsartikel (refereegranskat)abstract
- Changes in relative humidity of the ambient air, RH (%), cause wetting and drying of wood material, which results in non-uniform moisture contents or moisture gradients, and consequently in moisture-induced stresses and strains in the glued-laminated timber (glulam) members. The aim of the present paper is to perform a hygromechanical analysis to predict the mechanical behavior of glulam specimens exposed to two RH regimes, causing wetting from 50% to 90% RH and drying from 90% to 50% RH, and compare the numerical to the experimental results. The aims are also to quantitatively analyze the influence of characteristic material parameters required in the multi-Fickian moisture transport model and the mechanical model on moisture-induced strains and stresses in glulam specimens and to determine the possibility of cracking of the material by analyzing the maximum tensile stresses perpendicular to the grain. Accurate numerical predictions of moisture contents and moisture-induced strains are obtained in the glulam specimens during wetting and drying as compared to the experimental results. The influence of a particular characteristic material parameter on moisture-induced strains and stresses is characterized as significant, but not crucial when a rough numerical estimation of the mechanical behavior of the glulam beam exposed to RH changes is required.
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| 6. |
- Huc, Sabina, et al.
(författare)
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Rheological behavior of wood in stress relaxation under compression
- 2018
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Ingår i: Wood Science and Technology. - : SPRINGER. - 0043-7719 .- 1432-5225. ; 52:3, s. 793-808
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Tidskriftsartikel (refereegranskat)abstract
- Rheological behavior of wood under uniaxial compression along and perpendicular to the grain in constant environment was examined. Tests with constant deformation rate until failure and stress relaxation tests with constant deformation applied stepwise were carried out. The experimental results of stress relaxation showed nonlinear material behavior over time that got more prominent under high deformation levels. Considerable amount of stress relaxed during applying the deformation. Wood experienced greater stress relaxation along the grain than perpendicular to it. Three rheological models for orthotropic material were calibrated to the experimentally determined stress-time curves in longitudinal and transverse directions simultaneously. Small deformation levels assuming linear strains were accounted for in the models. Required elastic material parameters were determined from the tests with constant deformation rate. A model including the highest number of viscoelastic material parameters was the most successful in predicting stress relaxation of wood under stepwise deformation. Modeling indicated that wood behavior was very close to linear viscoelastic in relaxation under small deformation. The obtained material parameters made the model suitable for predicting rheological behavior of wood comprehensively, under sustained deformation or load in constant conditions.
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| 7. |
- Munch-Andersen, J., et al.
(författare)
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Fasteners and connections in the next Eurocode 5
- 2013
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Ingår i: Proceedings of the Cib - W18: Working Commission W18 - Timber Structures. - 1864-1784. ; , s. 399-401
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Pecenko, R., et al.
(författare)
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Model evaluation of heat and mass transfer in wood exposed to fire
- 2016
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Ingår i: Wood Science and Technology. - : Springer Science and Business Media LLC. - 0043-7719 .- 1432-5225. ; 50:4, s. 727-737
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents sensitivity analysis of coupled heat and moisture transfer model for timber exposed to fire. The objective of the analysis is to discover the non-influential model parameters and the model simplification accordingly. To achieve this, the standardized regression coefficient (SRC) method is introduced to determine the impact of specific permeability of dry timber K, bound water diffusion coefficient , vapour diffusion coefficient and heat of sorption on the two model outcomes, charring depth and total moisture content . The SRC method revealed that the least influential parameter is specific permeability of dry timber K. Therefore the model was adequately simplified by a more simple description of the energy equation, while preserving the accuracy of the results. Thus, the efficiency of the present coupled heat and moisture transfer model was increased.
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| 9. |
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| 10. |
- Pyykkö, Johan, et al.
(författare)
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Load-bearing capacity of slender dowel-type fasteners in Timber-Concrete Composite connections
- 2024
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Ingår i: Engineering structures. - : Elsevier. - 0141-0296 .- 1873-7323. ; 316
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Tidskriftsartikel (refereegranskat)abstract
- Load-bearing capacity of slender dowel-type fasteners of round ring-shank nails and U-shaped connectors (U-conn:s) of square cross-sectional nail thread used as connections in Timber-Concrete Composite structures have been studied, experimentally and with two different theoretical models. Tensile strength and withdrawal capacity of fasteners and embedment strength of timber were tested and evaluated. The parameters were used for calculation of the plastic hinge location in the fastener on the timber side and the load-bearing capacity of the connections. For this, both the European Yield Model known from the Eurocode 5, as well as a model where the load-bearing capacity is determined from mechanical equilibrium of fasteners in deformed state were used. Double shear push-out tests were carried out to determine the load-carrying capacity of the connections. The calculated values are compared to the experimental results. The models showed similar results for the U-conn:s regarding both plastic hinge location and load-bearing capacity. For the nails, all models show good correlation with experimental values, however, the model derived from the deformed state predicted both the plastic hinge location and the load-carrying capacity more accurately.
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