| 1. |
- Aasen, Elin M., et al.
(författare)
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From open to locked doors - From dependent to independent : Patient narratives of participation in their rehabilitation processes
- 2021
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Ingår i: Journal of Clinical Nursing. - : Wiley. - 0962-1067 .- 1365-2702. ; 30:15-16, s. 2320-2330
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Tidskriftsartikel (refereegranskat)abstract
- AIMS AND OBJECTIVES: The present study aimed to explore patients' experiences of participating in their rehabilitation process in the context of specialised rehabilitation in Norway.BACKGROUND: The rights of patients to participate in their care and treatment is an ideology that underlines newer international and Norwegian public documents. However, there is a gap between policy statements and clinical practice, and a discrepancy between patients' and professionals' statements about patient participation in rehabilitation.DESIGN: A qualitative approach with a narrative design.METHODS: Eleven patients were individually interviewed to tell their stories about the rehabilitation processes. We utilised narrative analysis with a three-dimensional space narrative structure including temporality, sociality and spatiality. This study followed the COREQ checklist.RESULTS: The analysis identified two throughout plots: 'person-centred culture' and 'time', and three plots which constructed how the patients participate in change through the rehabilitation process: (a) dependent-'open doors'; (b) motivation from within; and (c) independence-'locked doors'.CONCLUSIONS: Patient participation in rehabilitation was dependent on person-centred cultures in the unit and on different aspects of time. The dialogue and the power balance between the patients and the health personnel changed as the rehabilitation progressed. Motivation for rehabilitation had to come from within patients. The paternalistic ideology did not seem to dominate the specialised rehabilitation unit in the present study.RELEVANCE TO CLINICAL PRACTICE: This study gives new insight into how patients participate in change in the rehabilitation process. This can be valuable for healthcare professionals and governments. Insight into how the lack of person-centred focus can harm the rehabilitation process, and a deeper understanding of the meaning of time in the rehabilitation process is essential. These results may provide a stimulus for discussions on how patients might participate in their rehabilitation process.
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| 2. |
- Abrehdary, Majid, 1983-, et al.
(författare)
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A New Moho Depth Model for Fennoscandia with Special Correction for the Glacial Isostatic Effect
- 2021
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Ingår i: Pure and Applied Geophysics. - : Springer Nature. - 0033-4553 .- 1420-9136. ; 178:3, s. 877-888
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we present a new Moho depth model in Fennoscandia and its surroundings. The model is tailored from data sets of XGM2019e gravitationl field, Earth2014 topography and seismic crustal model CRUST1.0 using the Vening Meinesz-Moritz model based on isostatic theory to a resolution of 1° × 1°. To that end, the refined Bouguer gravity disturbance is determined by reducing the observed field for gravity effect of topography, density heterogeneities related to bathymetry, ice, sediments, and other crustal components. Moreover, stripping of non-isostatic effects of gravity signals from mass anomalies below the crust due to crustal thickening/thinning, thermal expansion of the mantle, Delayed Glacial Isostatic Adjustment (DGIA), i.e., the effect of future GIA, and plate flexure has also been performed. As Fennoscandia is a key area for GIA research, we particularly investigate the DGIA effect on the gravity disturbance and gravimetric Moho depth determination in this area. One may ask whether the DGIA effect is sufficiently well removed in the application of the general non-isostatic effects in such an area, and to answer this question, the Moho depth is determined both with and without specific removal of the DGIA effect prior to non-isostatic effect and Moho depth determinations. The numerical results yield that the RMS difference of the Moho depth from our model HVMD19 vs. the seismic CRUST19 and GRAD09 models are 3.8/4.2 km and 3.7/4.0 km when the above strategy for removing the DGIA effect is/is not applied, respectively, and the mean value differences are 1.2/1.4 km and 0.98/1.4 km, respectively. Hence, our study shows that the specific correction for the DGIA effect on gravity disturbance is slightly significant, resulting in individual changes in the gravimetric Moho depth up to − 1.3 km towards the seismic results. On the other hand, our study shows large discrepancies between gravimetric and seismic Moho models along the Norwegian coastline, which might be due to uncompensated non-isostatic effects caused by tectonic motions.
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| 3. |
- Abrehdary, Majid, 1983-, et al.
(författare)
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Estimating a combined Moho model for marine areas via satellite altimetric : gravity and seismic crustal models
- 2020
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Ingår i: Studia Geophysica et Geodaetica. - : Springer Science and Business Media LLC. - 0039-3169 .- 1573-1626. ; 64, s. 1-25
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Tidskriftsartikel (refereegranskat)abstract
- Isostasy is a key concept in geoscience in interpreting the state of mass balance between the Earth's lithosphere and viscous asthenosphere. A more satisfactory test of isostasy is to determine the depth to and density contrast between crust and mantle at the Moho discontinuity (Moho). Generally, the Moho can be mapped by seismic information, but the limited coverage of such data over large portions of the world (in particular at seas) and economic considerations make a combined gravimetric-seismic method a more realistic approach. The determination of a high-resolution of the Moho constituents for marine areas requires the combination of gravimetric and seismic data to diminish substantially the seismic data gaps. In this study, we estimate the Moho constituents globally for ocean regions to a resolution of 1° × 1° by applying the Vening Meinesz-Moritz method from gravimetric data and combine it with estimates derived from seismic data in a new model named COMHV19. The data files of GMG14 satellite altimetry-derived marine gravity field, the Earth2014 Earth topographic/bathymetric model, CRUST1.0 and CRUST19 crustal seismic models are used in a least-squares procedure. The numerical computations show that the Moho depths range from 7.3 km (in Kolbeinsey Ridge) to 52.6 km (in the Gulf of Bothnia) with a global average of 16.4 km and standard deviation of the order of 7.5 km. Estimated Moho density contrasts vary between 20 kg m-3 (north of Iceland) to 570 kg m-3 (in Baltic Sea), with a global average of 313.7 kg m-3 and standard deviation of the order of 77.4 kg m-3. When comparing the computed Moho depths with current knowledge of crustal structure, they are generally found to be in good agreement with other crustal models. However, in certain regions, such as oceanic spreading ridges and hot spots, we generally obtain thinner crust than proposed by other models, which is likely the result of improvements in the new model. We also see evidence for thickening of oceanic crust with increasing age. Hence, the new combined Moho model is able to image rather reliable information in most of the oceanic areas, in particular in ocean ridges, which are important features in ocean basins.
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| 4. |
- Abrehdary, Majid, 1983-, et al.
(författare)
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Moho density contrast in Antarctica determined by satellite gravity and seismic models
- 2021
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Ingår i: Geophysical Journal International. - : Oxford University Press (OUP). - 0956-540X .- 1365-246X. ; 225:3, s. 1952-1962
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Tidskriftsartikel (refereegranskat)abstract
- As recovering the crust-mantle/Moho density contrast (MDC) significantly depends on the properties of the Earth's crust and upper mantle, varying from place to place, it is an oversimplification to define a constant standard value for it. It is especially challenging in Antarctica, where almost all the bedrock is covered with a thick layer of ice, and seismic data cannot provide a sufficient spatial resolution for geological and geophysical applications. As an alternative, we determine the MDC in Antarctica and its surrounding seas with a resolution of 1 degrees x 1 degrees by the Vening Meinesz-Moritz gravimetric-isostatic technique using the XGM2019e Earth Gravitational Model and Earth2014 topographic/bathymetric information along with CRUST1.0 and CRUST19 seismic crustal models. The numerical results show that our model, named HVMDC20, varies from 81 kg m(-3) in the Pacific Antarctic mid-oceanic ridge to 579 kg m(-3) in the Gamburtsev Mountain Range in the central continent with a general average of 403 kg m(-3). To assess our computations, we compare our estimates with those of some other gravimetric as well as seismic models (KTH11, GEMMA12C, KTH15C and CRUST1.0), illustrating that our estimates agree fairly well with KTH15C and CRUST1.0 but rather poor with the other models. In addition, we compare the geological signatures with HVMDC20, showing how the main geological structures contribute to the MDC. Finally, we study the remaining glacial isostatic adjustment effect on gravity to figure out how much it affects the MDC recovery, yielding a correlation of the optimum spectral window (7 <= n <= 12) between XGM2019e and W12a GIA models of the order of similar to 0.6 contributing within a negligible +/- 14 kg m(-3) to the MDC.
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| 5. |
- Adamson, Göran, 1963-
(författare)
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Migrants and Crime in Sweden in the Twenty-First Century
- 2020
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Ingår i: Society. - : Springer. - 0147-2011 .- 1936-4725. ; 57:1, s. 9-21
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Tidskriftsartikel (refereegranskat)abstract
- In 2005, the Swedish Crime Prevention Agency published a report about the link between immigration and crime. Since then, no comprehensive study has been conducted even though Sweden has experienced a large influx of migrants in combination with a rising crime rate. This study conducted by Goran Adamson and Tino Sanandaji is the first purely descriptive scientific investigation on the matter in fifteen years. The investigation (from 2002 to 2017) covers seven distinct categories of crime, and distinguishes between seven regions of origin. Based on 33 per cent of the population (2017), 58 per cent of those suspect for total crime on reasonable grounds are migrants. Regarding murder, manslaughter and attempted murder, the figures are 73 per cent, while the proportion of robbery is 70 per cent. Non-registered migrants are linked to about 13 per cent of total crime. Given the fact that this group is small, crime propensity among non-registered migrants is significant.
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| 6. |
- Adegoke, Olutayo, et al.
(författare)
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Influence of laser powder bed fusion process parameters on voids, cracks, and microhardness of nickel-based superalloy alloy 247LC
- 2020
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Ingår i: Materials. - 1996-1944. ; 13:17
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Tidskriftsartikel (refereegranskat)abstract
- The manufacturing of parts from nickel-based superalloy Alloy 247LC by laser powder bed fusion (L-PBF) is challenging, primarily owing to the alloy’s susceptibility to cracks. Apart from the cracks, voids created during the L-PBF process should also be minimized to produce dense parts. In this study, samples of Alloy 247LC were manufactured by L-PBF, several of which could be produced with voids and crack density close to zero. A statistical design of experiments was used to evaluate the influence of the process parameters, namely laser power, scanning speed, and hatch distance (inherent to the volumetric energy density) on void formation, crack density, and microhardness of the samples. The window of process parameters, in which minimum voids and/or cracks were present, was predicted. It was shown that the void content increased steeply at a volumetric energy density threshold below 81 J/mm3. The crack density, on the other hand, increased steeply at a volumetric energy density threshold above 163 J/mm3. The microhardness displayed a relatively low value in three samples which displayed the lowest volumetric energy density and highest void content. It was also observed that two samples, which displayed the highest volumetric energy density and crack density, demonstrated a relatively high microhardness; which could be a vital evidence in future investigations to determine the fundamental mechanism of cracking. The laser power was concluded to be the strongest and statistically most significant process parameter that influenced void formation and microhardness. The interaction of laser power and hatch distance was the strongest and most significant factor that influenced the crack density. © 2020 by the authors.
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| 7. |
- Adegoke, Olutayo
(författare)
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Processability of Laser Powder Bed Fusion of Alloy 247LC : Influence of process parameters on microstructure and defects
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is about laser powder bed fusion (L-PBF) of the nickel-based superalloy: Alloy 247LC. Alloy 247LC is used mainly in gas turbine blades and processing the blades with L-PBF confers performance advantage over the blades manufactured with conventional methods. This is mainly because L-PBF is more suitable, than conventional methods, for manufacturing the complex cooling holes in the blades. The research was motivated by the need for academia and industry to gain knowledge about the processability of the alloy using L-PBF. The knowledge is essential in order to eventually solve the problem of cracking which is a major problem when manufacturing the alloy. In addition, dense parts with low void content should be manufactured and the parts should meet the required performance. Thus, the thesis answered some of the important questions related to process parameter-microstructure-defect relationships.The thesis presented an introduction in chapter 1. A literature review was made in chapter 2 to 4. In chapter 2, the topic of additive manufacturing was introduced followed by an overview of laser powder bed fusion. Chapter 3 focused on superalloys. Here, a review was made from the broader perspective of superalloys but was eventually narrowed down to the characteristics of nickelbased superalloys and finally Alloy 247LC. Chapter 4 reviewed the main research on L-PBF of Alloy 247LC. The methodology applied in the thesis was discussed in chapter 5. The thesis applied statistical design of experiments to show the influence of process parameters on the defects and microstructure, so a detail description of the method was warranted. This was given at the beginning of chapter 5 and followed by the description of the L-PBF manufacturing and the characterization methods. The main results and discussions, in chapter 6, included a preliminary investigation on how the process parameters influenced the amount of discontinuity in single track samples. This was followed by the results and discussions on the investigation of voids, cracks and microhardness in cube samples (detail presentation was given in the attached paper B). Finally, the thesis presented results of the microstructure obtainable in L-PBF manufactured Alloy 247LC. The initial results of the microstructure investigation were presented in paper A.
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| 8. |
- Adegoke, Olutayo, 1979-
(författare)
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Processability of Laser Powder Bed Fusion of Alloy 247LC-Influence of process parameters on microstructure and defects
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is about laser powder bed fusion (L-PBF) of the nickel-basedsuperalloy Alloy 247LC. Alloy 247LC is mainly used in gas turbine blades and processing the blades with L-PBF may confer performance advantage over the blades manufactured with conventional methods. This is mainly because L-PBFis more suitable, than conventional methods, for manufacturing the complex cooling holes in the blades. The research was motivated by the need for academia and industry to gain knowledge about the processability of the alloy using L-PBF. The knowledge is essential to eventually solve the problem of cracking encountered when processing the alloy. In addition, dense parts with low void content should be processed and the microstructure and properties should meett he required performance. Heat-treatment is usually performed to acquire final properties, so it is also of interest to study this aspect. Thus, the thesis answered some of the important questions related to process parameter-microstructure- property relationships.
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| 9. |
- Adegoke, Olutayo, et al.
(författare)
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Review of laser powder bed fusion of gamma-prime-strengthened nickel-based superalloys
- 2020
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Ingår i: Metals. - : MDPI AG. - 2075-4701. ; 10:8
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Tidskriftsartikel (refereegranskat)abstract
- This paper reviews state of the art laser powder bed fusion (L-PBF) manufacturing of γ′ nickel-based superalloys. L-PBF resembles welding; therefore, weld-cracking mechanisms, such as solidification, liquation, strain age, and ductility-dip cracking, may occur during L-PBF manufacturing. Spherical pores and lack-of-fusion voids are other defects that may occur in γ′-strengthened nickel-based superalloys manufactured with L-PBF. There is a correlation between defect formation and the process parameters used in the L-PBF process. Prerequisites for solidification cracking include nonequilibrium solidification due to segregating elements, the presence of liquid film between cells, a wide critical temperature range, and the presence of thermal or residual stress. These prerequisites are present in L-PBF processes. The phases found in L-PBF-manufactured γ′-strengthened superalloys closely resemble those of the equivalent cast materials, where γ, γ′, and γ/γ′ eutectic and carbides are typically present in the microstructure. Additionally, the sizes of the γ′ particles are small in as-built L-PBF materials because of the high cooling rate. Furthermore, the creep performance of L-PBF-manufactured materials is inferior to that of cast material because of the presence of defects and the small grain size in the L-PBF materials; however, some vertically built L-PBF materials have demonstrated creep properties that are close to those of cast materials.© 2020 by the authors. Licensee MDPI, Basel, Switzerland.
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| 10. |
- Agic, Adnan, 1967-
(författare)
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Edge Geometry Effects on Entry Phase by Forces and Vibrations
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Intermittent machining is in general strongly related to the large impacts in the entry phase and related vibrations. The influence of the impact forces and vibrations on the cutting process is dependent on workpiece material, structural properties of the tool-workpiece system, cutting edge geometries and cutting parameters. Cutting forces adopt generally a periodic behaviour that gives rise to forced vibrations. In addition, self-induced vibrations may arise because of lowrigidity and insufficient damping in the tool-workpiece system at specific cutting parameters. The ability of the cutting tool to carry the loads during the entry phase and minimize the vibrations is often the key parameter for an effective machining operation.This research work is based on the experiments, analytical studies and modelling. It was carried out through six main studies beginning with a force build-up analysis of the cutting edge entry into the workpiece in intermittent turning. This was followed by a second study, concentrated on modelling of the entry phase which has partly been explored through experiments and theory developed in the first study.The third part was focused on the influence of the radial depth of cut upon the entry of the cutting edge into the workpiece in a face milling application. The methodology for the identification of unfavourable radial depth of cut is also addressed herein. Next, effects of the cutting edge on the vibrations in an end milling application were investigated. This study was related to a contouring operation with the maximum chip thickness in the entry phase when machining steel, ISO P material.The results of this work provide some general recommendations when milling this type of workpiece material. After that, the focus was set on the dynamic cutting forces in milling. The force developments over a tooth engagement in milling showed to be strongly dependent on the cutting edge geometry. A significant difference between highly positive versus highly negative geometry was found.The implication of this phenomena on the stress state in the cutting edge and some practical issues were analysed. Finally, the role of the helix angle on the dynamic response of a workpiece was investigated. The modelling technique using force simulation and computation of the dynamic response by means of modal analysis was presented. Extensive experimental work was conducted to compare the modelling and experimentally obtained results. The modelling results showed a similar trend as the experimental results. The influence of helix angle on the cutting forces and the dynamic response was explained in detail.The research conducted in this work contributes to the deeper understanding of the influence of the cutting edge geometry and the cutting parameters on the force build up process during the entry phase. The presented studies investigate the force magnitudes, force rates and dynamic behaviour of the tools and workpieces when machining at the challenging entry conditions. The methodologies applied are focused on the physical quantities as forces and vibrations rather than the experimental studies that evaluate tool life. The methods and results of the research work are of great interest for the design of the cutting tools and optimization of the cutting processes.
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