| 1. |
- Allard, Christina, et al.
(författare)
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Rasbiologiskt språkbruk i statens rättsprocess mot sameby : DN Debatt 2015-06-11
- 2015
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Annan publikation (populärvet., debatt m.m.)abstract
- Statens hantering av forskningsresultat i rättsprocessen med Girjas sameby utgör ett hot mot Sverige som rättsstat och kunskapsnation. Åratal av svensk och internationell forskning underkänns och man använder ett språkbruk som skulle kunna vara hämtat från rasbiologins tid. Nu måste staten ta sitt ansvar och börja agera som en demokratisk rättsstat, skriver 59 forskare.
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| 2. |
- Ekman, Petter, 1988-, et al.
(författare)
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Accuracy and Speed for Scale-Resolving Simulations of the DrivAer Reference Model
- 2019
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Ingår i: WCX SAE World Congress Experience. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International.
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Konferensbidrag (refereegranskat)abstract
- In aerodynamic development of ground vehicles, the use of Computational Fluid Dynamics (CFD) is crucial for improving the aerodynamic performance, stability and comfort of the vehicle. Simulation time and accuracy are two key factors of a well working CFD procedure. Using scale-resolving simulations, accurate predictions of the flow field and aerodynamic forces are possible, but often leads to long simulation time. For a given solver, one of the most significant aspects of the simulation time/cost is the temporal resolution. In this study, this aspect is investigated using the realistic vehicle model DrivAer with the notchback geometry as the test case. To ensure a direct and accurate comparison with wind tunnel measurements, performed at TU Berlin, a large section of the wind tunnel is included in the simulation domain. All simulations are performed at a Reynolds number of 3.12 million, based on the vehicle length. Three spatial resolutions were compared, where it could be seen that a hybrid element mesh consisting of 102 million cells only revealed small differences to the finest mesh investigated, well as showing excellent agreement with wind tunnel measurements. An investigation of the temporal resolution is performed, in order to see its effect on the simulation time/cost and accuracy of the results. The finest temporal resolution resulted in a Courant-Friedrichs-Lewy number less than unity, while the coarsest reached a CFL number of around 100. From these results, it is seen that it is possible to reduce the simulation time with more than 90 % (CFL 20) and still keep sufficient accuracy of the forces and important features of the flow field.
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| 3. |
- Larsson, Karin, et al.
(författare)
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Increased levels of the cardiovascular disease risk biomarkers GDF15 and myostatin in patients with chronic lymphocytic leukemia
- 2021
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Ingår i: Growth Factors. - : Informa UK Limited. - 0897-7194 .- 1029-2292. ; 38:3-4, s. 189-196
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Tidskriftsartikel (refereegranskat)abstract
- Individuals suffering from cancer, including hematological malignancies, are at increased risk of cardiovascular disease (CVD). Elevated levels of several biomarkers in blood are associated with an increased risk of CVD. The aim of this study was to investigate whether a subset of such CVD risk biomarkers was elevated in patients with untreated chronic lymphocytic leukemia (CLL). Blood plasma and serum from 139 CLL patients and 71 healthy age-matched controls were analyzed for 11 proposed CVD risk biomarkers. The CLL cohort displayed a more heterogeneous pattern of biomarker expression compared to controls. The majority, eight out of 11, analyzed CVD risk biomarkers differed significantly in concentrations between CLL patients and controls. Increased levels of the biomarkers GDF15 and myostatin have not previously been reported in CLL. Further prospective studies are warranted to investigate whether these biomarkers predict future cardiovascular events in patients with CLL.
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| 4. |
- Rollborn, Niclas, et al.
(författare)
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Good Agreement Between Hba1c Analyzed Using Capillary Electrophoresis, HPLC, Immunological and Enzymatic Methods
- 2019
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Ingår i: Journal of Diabetes, Metabolism and its Complications. ; 1:1, s. 1-7
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: Hemoglobin A1c (HbA1c) is an essential marker for assessment of glycemic control in diabetes patients. The aim of this study was to evaluate the agreement between different HbA1c methods.Methodology: We used blood samples to compare HbA1c results analyzed with Capillarys 3 Tera, Roche Tina-Quant HbA1c Gen 3, BioRad Variant II Turbo (3 sites), Mono S® and Abbott Architect enzymatic method. The comparisons were made as paired instrument comparisons with Capillarys 3 Tera.Results: The linear correlations between the HbA1c methods were as follows:Cobas 6000 = 0.982 x Capillarys 3 Tera + 0.975, R² = 0.994;Architect c8000 = 0.982 x Capillarys 3 Tera + 1.064, R² = 0.994; Mono S® = 0.916 x Capillarys 3 Tera + 3.397, R² = 0.965;BioRad Variant II Turbo = 0.923 x Capillarys 3 Tera + 4.062, R² = 0.990; Tosoh G8 = 0.963 x Capillarys 3 Tera + 3.895, R² = 0.996.Conclusions: The different instrument platforms showed the best agreement in the 50-70 mmol/mol interval. Above and below this range the methods separated into 2 groups, one consisting of Capillarys 3 Tera, Roche Tina-Quant and Abbott enzymatic method and the other group consisting of BioRad Variant II Turbo, Tosoh G8 and Mono S®.
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| 5. |
- Abujrais, Sandy, et al.
(författare)
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A sensitive method detecting trace levels of levonorgestrel using LC-HRMS
- 2019
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Ingår i: Contraception. - : Elsevier BV. - 0010-7824 .- 1879-0518. ; 100:3, s. 247-249
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To develop a high resolution mass spectrometry (HRMS) method to quantify levonorgestrel (LNG) in serum. Study design: Levonorgestrel was extracted using solid phase extraction and measured using liquid chromatography (LC) HRMS. Results: Low limit of quantification (LLOQ) was 25 pg/mL and low limit of detection (LLOD) was 12.5 pg/mL. Precision and accuracy bias were <10%. LNG in serum samples from Mirena® users ranged between 37 to 219 pg/mL (n=12). In eight out of 22 patients with suspected intrauterine device (IUD) expulsion LNG was detected (26–1272 pg/mL). Conclusion: A sensitive, fast and simple LC-HRMS method was developed to detect trace levels of LNG. © 2019 Elsevier Inc.
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| 6. |
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| 7. |
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| 8. |
- Ahlström, Torbjörn, et al.
(författare)
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Genom livet i den långsamma filen
- 2005
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Ingår i: Arkeologi och naturvetenskap : Gyllenstiernska Krapperupstiftelsens Symposium Nr 6 År 2003 - Gyllenstiernska Krapperupstiftelsens Symposium Nr 6 År 2003. - 1100-7095. - 9187944146 ; 6, s. 215-234
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Ahlström, Torbjörn, et al.
(författare)
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Mesolithic human skeletal remains from Tågerup, Scania, Sweden
- 2003
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Ingår i: Mesolithic on the move : papers presented at the Sixth International Conference on the Mesolithic in Europe, Stockholm 2000 - papers presented at the Sixth International Conference on the Mesolithic in Europe, Stockholm 2000. - 1842170899 ; , s. 478-484
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Konferensbidrag (refereegranskat)
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| 10. |
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| 11. |
- Almqvist, Torbjörn, et al.
(författare)
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A comparison between computational fluid dynamic and Reynolds approaches for simulating transient EHL line contacts
- 2004
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Ingår i: Tribology International. - 0301-679X .- 1879-2464. ; 37:1, s. 61-69
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Tidskriftsartikel (refereegranskat)abstract
- When simulating elastohydrodynamic lubrication (EHL), the Reynolds equation is the predominating partial differential equation for prediction of the fluid flow. Also very few attempts have been carried out using the full momentum and continuity equations separately. The aim of this investigation is to compare two different approaches for simulation of EHL line contacts where a single ridge travels through an EHL conjunction. One of the approaches is based on the Reynolds equation, addressing the coupling between the pressure and the film thickness. The solver uses the advantages of multilevel techniques to speed up the convergence rate. The other approach is based on commercial CFD software. The software uses the momentum and continuity equations in their basic form, enabling numerical simulations outside the contact regions, as well as in the thin film region to be carried out. The numerical experiments show that, under the running conditions chosen, only small deviations between the two approaches can be observed. The results are encouraging from several viewpoints: validation of the codes, the possibilities of further developments of the CFD approach and the justification of using a Reynolds approach under the running conditions chosen
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| 12. |
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| 13. |
- Almqvist, Torbjörn, et al.
(författare)
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Some remarks on the validity of Reynolds equation in the modeling of lubricant film flows on the surface roughness scale
- 2004
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Ingår i: Journal of tribology. - : ASME International. - 0742-4787 .- 1528-8897. ; 126:4, s. 703-710
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this paper is to investigate the flow in a lubricant film on the surface roughness scale and to compare the numerical solutions obtained by two different solution approaches. This is accomplished firstly by the CFD-approach (computational fluid dynamic approach) where the momentum and continuity equations are solved separately, and secondly the Reynolds equation approach, which is a combination and a simplification of the above equations. The rheology is assumed to be both Newtonian and non-Newtonian. An Eyring model is used in the non-Newtonian case. The result shows that discrepancies between the two approaches may occur, primarily due to a singularity which appears in the momentum equations when the stresses in the lubricant attain magnitudes that are common in EHL. This singularity is not represented by the Reynolds equation. If, however, the rheology is shifted to a non-Newtonian Eyring model the deviations between the two solution approaches is removed or reduced. The second source of discrepancies between the two approaches is the film thickness to wavelength scale ω. It will be shown that the Reynolds equation is valid until this ratio is approximately O(10-2).
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| 14. |
- Almqvist, Torbjörn, et al.
(författare)
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THD analysis of tilting pad thrust bearings : comparison between theory and experiments
- 2000
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Ingår i: Journal of tribology. - : ASME International. - 0742-4787 .- 1528-8897. ; 122:2, s. 412-417
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Tidskriftsartikel (refereegranskat)abstract
- The objective of the present research is to verify a THD model of hydrodynamic thrust bearings. The developed model of a pivoted pad bearing, which can tilt both radially and circumferentially, allows for three-dimensional temperature distribution in the oil film and in the pad, as well as two-dimensional temperature variation in the runner. Viscosity and density are treated as functions of both temperature and pressure. Experiments have been performed on a test rig, containing two identical equalizing pivoted pad thrust bearings. Power loss, runner temperature, and pressure profiles as a function of load and rotational speed are compared for both theoretical and experimental investigations. Fairly good agreement has been found when the oil inlet temperature and heat transfer coefficients have been estimated in order to get the same runner temperature in both theory and experiment.
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| 15. |
- Almqvist, Torbjörn, et al.
(författare)
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The Navier-Stokes approach for thermal EHL line contact solutions
- 2002
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Ingår i: Tribology International. - 0301-679X .- 1879-2464. ; 35:3, s. 163-170
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Tidskriftsartikel (refereegranskat)abstract
- The complicated nature of the EHL-problem has so far forced researchers to develop their own computer codes. These codes are ultimately based on the Reynolds equation, and if thermal EHL-simulations are required, a simultaneous solution of the equation of energy also has to be performed. To date only a few attempts to solve the full equations of momentum and continuity as well as equations of energy have been performed. However, such an approach will give extended possibilities of simulating EHL-contacts; i.e. the computational domain can be expanded and it will be possible to simulate the flow, not only in the contact but also around the contact. Another possibility is to investigate how the altering length scales of the surface roughness influence the behaviour of the flow in the contact. However, the aim of the work presented in this paper is to investigate the possibilities of using a commercial CFD-code (computational fluid dynamics code) based on the above-mentioned equations for simulating thermal EHL. The rheology is assumed to be Newtonian and the equations of momentum and continuity are then commonly referred to as the Navier-Stokes equations (N-S equations). The geometry chosen for the simulations is a smooth line contact geometry, for which the results from the simulations show that it is possible to use the N-S equations for thermal EHL for contact pressures up to approximately 0.7 GPa. The code used in this work is the commercial CFD software (CFX 4.3 user guide). There is a limitation in the N-S approach due to a singularity that can occur in the equation of momentum when the principal shear stresses in the film become too high. However, a thermal approach makes it possible to simulate EHL-contacts at higher loads compared with an isothermal approach, due to the reduction of the viscosity in the former approach. The singularity is not present in the Reynolds approach.
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| 16. |
- Almqvist, Torbjörn, et al.
(författare)
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Thermal transient rough EHL line contact simulations by aid of computational fluid dynamics
- 2008
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 41:8, s. 683-693
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Tidskriftsartikel (refereegranskat)abstract
- Reynolds equation is the pre-dominantly used PDE for modelling the fluid flow or more accurately the fluid pressure in an elastohydrodynamic lubrication (EHL) contact. The equation is derived by combining the two conservation equations of momentum and continuity into a single equation for the fluid pressure. The numerical approach for theoretical investigations performed on EHL contacts in this work is somewhat different. The modelling of the fluid flow is based on a computational fluid dynamic (CFD) technique. The fluid flow is simulated by aid of the equations of momentum and continuity in a more complete form and when the thermodynamics is incorporated, the equation of energy. The aim of the investigation was to examine whether the CFD technique could be used to handle thermal transient rough EHL line contacts. It is shown that commercial CFD software can be modified to meet such requirements. The influence of thermal effects on the flow under sliding motion was investigated. The non-Newtonian model used in this work is the Ree-Eyring model. It is shown that the choice of the Eyring stress in the model influences flow in the contacts. If the thermal properties of the surrounding solids differ, it has been shown experimentally and theoretically that a dimple or increased central film thickness may appear in the EHL contacts. This work shows that the governing mechanisms that result in the dimple are also present in thermal transient rough EHL line contacts.
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| 17. |
- Alrutz, Marie, et al.
(författare)
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Projektledning
- 2013
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Bok (populärvet., debatt m.m.)abstract
- Projektledning är ett yrke med egen certifiering. Det pågår en spännande utveckling inom området och det blir allt viktigare att hålla sig ajour med utvecklingen.Det övergripande målet med den här handboken är att vara en ständigt aktuell heltäckande bok om projektarbete. Innehållsmässigt täcker den både frågor som har med struktur och styrning att göra och frågor om ledning av människor och mänskliga processer i grupp. Kompetens inom projekt byggs av både kunskap och erfarenhet. Vi följer kontinuerligt aktuell forskning inom dessa områden och bjuder in intressanta forskare att medverka som författare. Vi skildrar verkliga projekt och låter erfarenheterna få plats, både de bästa erfarenheterna och de utmaningar som man tagit sig igenom.Handboken är levande och det innebär att artiklar tas bort för att ge plats för nya, i takt med att den uppdateras fortlöpande.
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| 18. |
- Amankwah, Henry, et al.
(författare)
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A Duality-Based Derivation of the Maximum Flow Formulation of the Open-Pit Design Problem
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Open-pit mining is a surface mining operation whereby ore, or waste, is excavated from the surface of the land. The open-pit design problem is deciding on which blocks of an ore deposit to mine in order to maximize the total profit, while obeying digging constraints concerning pit slope and block precedence. The open-pit design problem can be formulated as a maximum flow problem in a certain capacitated network, as first shown by Picard in 1976. His derivation is based on a restatement of the problem as a quadratic binary program. We give an alternative derivation of the maximum flow formulation, which uses only linear programming duality.
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| 19. |
- Amankwah, Henry, et al.
(författare)
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A maximum flow formulation of a multi-period open-pit mining problem
- 2014
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Ingår i: Operational Research. - : Springer Berlin/Heidelberg. - 1109-2858 .- 1866-1505. ; 14:1, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- We consider the problem of finding an optimal mining sequence for an open pit during a number of time periods subject to only spatial and temporal precedence constraints. This problem is of interest because such constraints are generic to any open-pit scheduling problem and, in particular, because it arises as a Lagrangean relaxation of an open-pit scheduling problem. We show that this multi-period open-pit mining problem can be solved as a maximum flow problem in a time-expanded mine graph. Further, the minimum cut in this graph will define an optimal sequence of pits. This result extends a well-known result of J.-C. Picard from 1976 for the open-pit mine design problem, that is, the single-period case, to the case of multiple time periods.
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| 20. |
- Amankwah, Henry, et al.
(författare)
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A Multi-Parametric Maximum Flow Characterization of the Open-Pit Scheduling Problem
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We consider the problem of finding an optimal mining schedule for an openpit during a number of time periods, subject to a mining capacity restriction for each time period. By applying Lagrangian relaxation to the capacities, a multi-parametric formulation is obtained. We show that this formulation can be restated as a maximum flow problem in a time-expanded network. This result extends a well-known result of Picard from 1976 for the open-pit design problem, that is, the single-period case, to the case of multiple time periods.
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| 21. |
- Amankwah, Henry, 1969-
(författare)
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Mathematical Optimization Models and Methods for Open-Pit Mining
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Open-pit mining is an operation in which blocks from the ground are dug to extract the ore contained in them, and in this process a deeper and deeper pit is formed until the mining operation ends. Mining is often a highly complex industrial operation, with respect to both technological and planning aspects. The latter may involve decisions about which ore to mine and in which order. Furthermore, mining operations are typically capital intensive and long-term, and subject to uncertainties regarding ore grades, future mining costs, and the market prices of the precious metals contained in the ore. Today, most of the high-grade or low-cost ore deposits have already been depleted, and to obtain sufficient profitability in mining operations it is therefore today often a necessity to achieve operational efficiency with respect to both technological and planning issues.In this thesis, we study the open-pit design problem, the open-pit mining scheduling problem, and the open-pit design problem with geological and price uncertainty. These problems give rise to (mixed) discrete optimization models that in real-life settings are large scale and computationally challenging.The open-pit design problem is to find an optimal ultimate contour of the pit, given estimates of ore grades, that are typically obtained from samples in drill holes, estimates of costs for mining and processing ore, and physical constraints on mining precedence and maximal pit slope. As is well known, this problem can be solved as a maximum flow problem in a special network. In a first paper, we show that two well known parametric procedures for finding a sequence of intermediate contours leading to an ultimate one, can be interpreted as Lagrangian dual approaches to certain side-constrained design models. In a second paper, we give an alternative derivation of the maximum flow problem of the design problem.We also study the combined open-pit design and mining scheduling problem, which is the problem of simultaneously finding an ultimate pit contour and the sequence in which the parts of the orebody shall be removed, subject to mining capacity restrictions. The goal is to maximize the discounted net profit during the life-time of the mine. We show in a third paper that the combined problem can also be formulated as a maximum flow problem, if the mining capacity restrictions are relaxed; in this case the network however needs to be time-expanded.In a fourth paper, we provide some suggestions for Lagrangian dual heuristic and time aggregation approaches for the open-pit scheduling problem. Finally, we study the open-pit design problem under uncertainty, which is taken into account by using the concept of conditional value-atrisk. This concept enables us to incorporate a variety of possible uncertainties, especially regarding grades, costs and prices, in the planning process. In real-life situations, the resulting models would however become very computationally challenging.
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| 22. |
- Amankwah, Henry, et al.
(författare)
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On the use of Parametric Open-Pit Design Models for Mine Scheduling - Pitfalls and Counterexamples
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper discusses a Lagrangian relaxation interpretation of the Picard and Smith (2004) parametric approach to open-pit mining, which finds a sequence of intermediate contours leading to an ultimate one. This method is similar to the well known parametric approach of Lerchs and Grossmann (1965). We give examples of worst case performance, as well as best case performance of the Picard-Smith approach. The worst case behaviour can be very poor in that we might not obtain any intermediate contours at all. We also discuss alternative parametric methods for finding intermediate contours, but conclude that such methods seem to have inherent weaknesses.
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| 23. |
- Amankwah, Henry, et al.
(författare)
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Open-pit mining with uncertainty : A conditional value-at-risk approach
- 2013
-
Ingår i: Optimization Theory, Decision Making, and Operations Research Applications. - New York : Springer. - 9781461451334 - 9781461451341 ; , s. 117-139
-
Konferensbidrag (refereegranskat)abstract
- The selection of a mine design is based on estimating net present values of all possible, technically feasible mine plans so as to select the one with the maximum value. It is a hard task to know with certainty the quantity and quality of ore in the ground. This geological uncertainty and also the future market behavior of metal prices and foreign exchange rates, which are always uncertain, make mining a high risk business. Value-at-Risk (VaR) is a measure that is used in financial decisions to minimize the loss caused by inadequate monitoring of risk. This measure does, however, have certain drawbacks such as lack of consistency, nonconvexity, and nondifferentiability. Rockafellar and Uryasev [J. Risk 2, 21-41 (2000)] introduce the Conditional Value-at-Risk (CVaR) measure as an alternative to the VaR measure. The CVaR measure gives rise to a convex optimization problem. An optimization model that maximizes expected return while minimizing risk is important for the mining sector as this will help make better decisions on the blocks of ore to mine at a particular point in time. We present a CVaR approach to the uncertainty involved in open-pit mining. We formulate investment and design models for the open-pit mine and also give a nested pit scheduling model based on CVaR. Several numerical results based on our models are presented by using scenarios from simulated geological and market uncertainties.
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| 24. |
- Amankwah, Henry, et al.
(författare)
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Open-Pit Mining with Uncertainty - A Conditional Value-at-Risk Approach
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The selection of a mine design is based on estimating net present values of all possible, technically feasible mine plans so as to select the one with the maximum value. It is a hard task to know with certainty the quantity and quality of ore in the ground. This geological uncertainty, and also the future market behaviour of metal prices and foreign exchange rates, which are impossible to be known with certainty, make mining a high risk business. Value-at-Risk (VaR) is a measure that is used in financial decisions to minimize the loss caused by inadequate monitoring of risk. This measure does however have certain drawbacks such as lack of consistency, nonconvexity, and nondifferentiability. Rockafellar and Uryasev (2000) introduce the Conditional Value-at-Risk (CVaR) measure as an alternative to the VaR measure. The CVaR measure gives rise to a convex problem. An optimization model that maximizes expected return while minimizing risk is important for the mining sector as this will help make better decisions on the blocks of ore to mine at a particular point in time. We present a CVaR approach to the uncertainty involved in open-pit mining. We formulate investment and design models for the open-pit mine and also give a nested pit scheduling model based on CVaR. Several numerical results based on our models are presented by using scenarios from simulated geological and price uncertainties.
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| 25. |
- Amankwah, Henry, et al.
(författare)
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Open-Pit Production Scheduling - Suggestions for Lagrangian Dual Heuristic and Time Aggregation Approaches
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Open-pit production scheduling deals with the problem of deciding what and when to mine from an open-pit, given potential profits of the different fractions of the mining volume, pit-slope restrictions, and mining capacity restrictions for successive time periods. We give suggestions for Lagrangian dual heuristic approaches for the open-pit production scheduling problem. First, the case with a single mining capacity restriction per time period is considered. For this case, linear programming relaxations are solved to find values of the multipliers for the capacity restrictions, to be used in a Lagrangian relaxation of the constraints. The solution to the relaxed problem will not in general satisfy the capacity restrictions, but can be made feasible by adjusting the multiplier values for one time period at a time. Further, a time aggregation approach is suggested as a way of reducing the computational burden of solving linear programming relaxations, especially for largescale real-life mine problems. For the case with multiple capacity restrictions per time period we apply newly developed conditions for optimality and nearoptimality in general discrete optimization problems to construct a procedure for heuristically constructing near-optimal intermediate pits.
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| 26. |
- Amirpour, Sepideh, 1980, et al.
(författare)
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Highly thermal conductive graphene-based heatsink tailored for electric propulsion SiC-based inverter
- 2024
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Ingår i: Applied Thermal Engineering. - 1359-4311. ; 243
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Tidskriftsartikel (refereegranskat)abstract
- This study introduces an innovative multidisciplinary design approach for highly conductive and lightweight pin-fin-based heatsinks leveraging the advantages of graphene technology. The primary objective is to optimize the thermal management of silicon carbide (SiC) based inverters within electric vehicles (EVs). To closely emulate the real SiC power module, comprehensive analyses, including scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), are performed on the module. A detailed fluid dynamics model utilizing a 3D-conjugate heat transfer (CHT) methodology is employed to evaluate the thermal behavior of SiC power switches in contact with the coolant. The multidisciplinary analysis is initially implemented on an aluminum-based heatsink, validated experimentally, and subsequently compared to graphene. The integration of graphene in the heatsink design demonstrates notable improvements, including a 24.4 % increase in the heat transfer coefficient (HTC) and a 19.6 % reduction in thermal resistance (sink to fluid) at a 6 l/min fluid flow rate compared to its aluminum counterpart. Consequently, the SiC chips within the graphene-based heatsink exhibit an 11.5 % lower temperature rise compared to the aluminum version. The improvements in the cooling solution for SiC inverters in EVs, achieved through the adoption of graphene instead of traditional metals, serve as a proof of concept. This signifies a step forward in prioritizing the crucial balance between performance and power density.
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| 27. |
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| 28. |
- Andersson, Per-Åke, 1945-
(författare)
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Multi-year maintenance optimisation for paved public roads - segment based modelling and price-directive decomposition
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I avhandlingen studeras hur kostnadseffektiva underhålls- (uh-)planer för belagd väg kan genereras, på basis av information om aktuellt vägytetillstånd och funktionella modeller för kostnads- och tillståndsförändringar, delvis utvecklade i samarbete med svenska Vägverket (VV). Tilltänkt användning är på strategisk och programnivå, innan mer detaljerad objektinformation finns att tillgå. Till skillnad från hittills använda modeller, så genereras individuella uh-planer för varje vägsegment (en homogen vägsträcka vad gäller aktuellt beläggningstillstånd och beläggningshistorik), i kontinuerliga tillstånds- och åtgärdsrum. Genom användning av Lagrangerelaxerande optimeringsteknik, så kan de speciella nytto/kostnads-kvot-villkor som VV ålägger varje uh-objekt naturligen hanteras med dualpriser för budgetvillkoren. Antalet vägsegment som konkurrerar om budgetmedlen är vanligtvis stort. Data från VV:s Vägdatabank för Värmland har använts, omfattande ca 9000 vägsegment. Genom den stora datamängden har datorprogrammen implementerats för parallellbearbetning. Under avhandlingsarbetet har projektet beviljats tillgång till Monolith PCklustret vid NSC. För att kunna reducera optimeringskörtiderna har modell- och metodutveckling varit nödvändig. Genom att aggregera vägsegmenten till vägklasser har goda startvärden på dualpriserna erhållits. Genom utvecklingen av en speciell restvärdesrutin har den explicit behandlade tidsperioden kunnat reduceras. Vid lösandet av det duala subproblemet har speciell uppmärksamhet ägnats åt de diskretiseringseffekter som uppstår i metoden dynamisk programmering. En typ av tillämpning avser ett delvägnät, exempelvis en väg. Valideringsstudier har genomförts på väg 63 i Värmland – med lovande men inte tillfredsställande resultat (se nedan). En speciell modell för samordnat uh beaktar stordriftsfördelarna vid samtidig åtgärd på en hel vägsträcka. Den andra huvudtypen av studier gäller ett helt nätverk. Flera metodtyper har tillämpats, både för att lösa de relaxerade optimeringsproblemen och för att generera uhplaner som uppfyller budgetvillkoren. För en anständig diskretisering är körtiderna för hela Värmland mindre än 80 CPU-timmar. Genom en a posteriori primal heuristik reduceras kraven på parallellbearbetning till ett litet PC-kluster. Avhandlingen studerar vidare effekterna av omfördelade budgetmedel samt en övergång till en transparent, stokastisk modell – vilka båda visar små avvikelser från basmodellen.Optimeringsresultaten för Värmland indikerar att budgetnivåer på ca 40% av Värmlands verkliga uh-budget är tillräckliga. Dock saknas viktiga kostnadsdrivande faktorer i denna första modellomgång, exempelvis vissa funktionella prestanda (säkerhet), all miljöpåverkande prestanda (buller etc.) och strukturell prestanda (ex.vis bärighet, som enbart modelleras via ett åldersmått). För ökad tilltro till PMS i allmänhet och optimering i synnerhet, bör avvikelserna analyseras ytterligare och leda till förbättringar vad gäller tillståndsmätning, tillståndseffekt- & kostnadsmodellering samt matematisk modellering & implementering.
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| 29. |
- Andersson-Sköld, Yvonne, 1957-, et al.
(författare)
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Coal tar-containing asphalt : Resource or hazardous waste?
- 2007
-
Ingår i: Journal of Industrial Ecology. - : Wiley-Blackwell. - 1088-1980 .- 1530-9290. ; 11:4, s. 99-116
-
Tidskriftsartikel (refereegranskat)abstract
- Coal tar was used in Sweden for the production of asphalt and for the drenching of stabilization gravel until 1973. The tar has high concentrations of polycyclic aromatic hydrocarbons (PAH), some of which may be strongly carcinogenic. Approximately 20 million tonnes of tar-containing asphalt is present in the public roads in Sweden. Used asphalt from rebuilding can be classified as hazardous waste according to the Swedish Waste Act. The cost of treating the material removed as hazardous waste can be very high due to the large amount that has to be treated, and the total environmental benefit is unclear. The transport of used asphalt to landfill or combustion will affect other environmental targets. The present project, based on three case studies of road projects in Sweden, evaluates the consequences of four scenarios for handling the material: reuse, landfill, biological treatment, and incineration. The results show that reuse of the coal tar-containing materials in new road construction is the most favorable alternative in terms of cost, material use, land use, energy consumption, and air emissions.
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| 30. |
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| 31. |
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| 32. |
- Anund, Anna, 1964-, et al.
(författare)
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Skolskjutsbarns inblandning i olyckor 1994-2001
- 2003
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Sammanlagt har polisen rapporterat 256 olyckor med totalt 361 skadade eller dödade barn i samband med förmodade skolskjutsresor under åren 1994–2001. Majoriteten av barnen har drabbats när de befunnit sig utanför bussen. Den vanligaste händelsen vid olyckorna är att barnen har sprungit ut bakom eller framför bussen (51 %).Ytterligare 13 procent av olyckorna har inträffat då barn har klämts eller blivit påkörda av bussen vid hållplatsen. En majoritet av olyckorna i vilka barn har skadats har således inträffat i samband med på- och avstigning.Föreliggande rapport baseras på en studie med syfte att skapa en samlad bild av orsaken till att barn skadas och dödas vid resor med skolskjuts. I befintliga olycksregister finns tyvärr ingen notering om en skolskjuts varit inblandad i inträffad olycka. Analysen har därför skett i tre steg.1. Alla personskadeolyckor med barn i åldern 0–18.2. Alla personskadeolyckor med barn 6–16 år, skoldagar klockan 600–1659 i vilka buss, taxi eller gående varit inblandade.3. Personskadeolyckor i steg 2 som bedömts vara anknutna till skolskjuts (eller skolresa med vanlig linjetrafik).
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| 33. |
- Axelsson, Maria, 1976-
(författare)
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Ifrågasatta företagare : Konkursförvaltares syn på kvinnor och män som företagsgäldenärer under 1900-talet
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The principle purpose of this thesis has been to study and analyse the conception of men and women in business bankruptcy during the 20th century. The analysis is built on a theoretical gender perspective and, combining this view and business and bankruptcy research, the thesis has focused on five themes: business networks, bank contacts, business competence, business characteristics and finally bankruptcy causes. These themes have been in focus when analysing bankruptcies in Uppsala 1920-1939, 1988, 1992 and 1996. A questionnair- and interview study with receivers active in Sweden 2001 has also been carried out. From the bankruptcy cases that have been studied, no specific gender differences have really been discovered. There were some variations between men and women, but it is very hard to claim that these are related to the sex of the debtor more than to the branch or to the individuals. Changes from the inter-war period to the latter part of the 20th century are in these respects also small. The image that the receivers gave through the questionnaire and interview study indicates on the other hand that there existed a conception that men and women seemed different as business owners. It is obvious that there were many receivers who thought that women were different from men in a situation of business bankruptcy, even though several of them stated that they did not beleive in any gender differences.
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| 34. |
- Bacchetti, Tiziana, et al.
(författare)
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Effects of Seven Weeks of Combined Physical Training on High-Density Lipoprotein Functionality in Overweight/Obese Subjects
- 2023
-
Ingår i: Metabolites. - : MDPI. - 2218-1989 .- 2218-1989. ; 13:10, s. 1068-1068
-
Tidskriftsartikel (refereegranskat)abstract
- Our study aimed to investigate the effects of exercise on HDL composition and functional properties in overweight/obese subjects. Eighteen overweight/obese subjects (nine F and nine M, BMI = 30.3 ± 3 kg/m2) attended supervised training for 7 weeks. The protocol included combined resistance and conditioning training four to five times each week. The activity of the antioxidant enzyme paraoxonase-1 (PON1) associated with HDL was evaluated in all subjects before and after the training intervention. Moreover, myeloperoxidase (MPO) levels and oxidative stress markers (ox-LDLs and total antioxidant capacity) were studied in the serums of the subjects. At the end of the intervention, the activity of PON1 was increased (p < 0.0001), and MPO levels and the MPO/PON1 ratio were decreased (p < 0.0001). In addition, a significant improvement in muscle strength and maximal oxygen uptake (VO2max) (p < 0.0001) and a significant reduction in total and visceral adipose tissue mass (p < 0.001) and waist circumference (p < 0.008), without any significant decrease in body weight, were observed. A significant correlation was established between serum MPO/PON ratios, HDL redox activity and ox-LDLs. In conclusion, our results demonstrate that exercise training, without modifications of dietary habits, improved HDL functionality in overweight/obese adults, without any significant reduction in BMI or modifications of glucose and lipid biochemical parameters.
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| 35. |
- Bigdeli, Sedigheh, 1984, et al.
(författare)
-
Strategies for High-Temperature Corrosion Simulations of Fe-Based Alloys Using the Calphad Approach : Part I
- 2021
-
Ingår i: Journal of Phase Equilibria and Diffusion. - : Springer Nature. - 1547-7037 .- 1863-7345. ; 42:3, s. 403-418
-
Tidskriftsartikel (refereegranskat)abstract
- The environmental degradation of materials at high temperatures limits the useful life of different industrial components and hinders the development of more economical and environmentally friendly processes for the energy production. Despite the importance of this phenomena, a model to predict lifetime of materials that degrade due to high-temperature corrosion has up till now been lacking due to limitations of the computational possibilities and the complex nature of oxidation. In the present work we develop some strategies to model high-temperature corrosion in Fe-based alloys using the Calphad (Calculation of Phase Diagrams) approach. It is proposed that kinetic-based simulations for oxidation of Al and Cr can accurately represent the lifetime of the protective layers in FeCrAl and FeCr alloys at different temperatures in air. The oxide systems are in addition investigated by equilibrium calculations. The corrosion mechanisms of FeCr and FeCrAl alloys are discussed based on theoretical and experimental knowledge.
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| 36. |
- Boethius, Adam, et al.
(författare)
-
Assessing laser ablation multi-collector inductively coupled plasma mass spectrometry as a tool to study archaeological and modern human mobility through strontium isotope analyses of tooth enamel
- 2022
-
Ingår i: Archaeological and Anthropological Sciences. - : Springer Science and Business Media LLC. - 1866-9557 .- 1866-9565. ; 14:5
-
Tidskriftsartikel (refereegranskat)abstract
- To evaluate the possibility of obtaining detailed individual mobility data from archaeological teeth, the strontium isotope ratios on 28 human teeth from three separate Early-Mid Holocene, Swedish, foraging contexts (Norje Sunnansund, Skateholm and Västerbjers) were analysed through laser ablation. The teeth/individuals have previously been analysed using traditional bulk sampled thermal ionisation mass spectrometry. To validate the conclusions regarding the archaeological teeth, a tooth from a modern man with a known background was also analysed. The result shows that all of the teeth display less than 0.4% discrepancy between the mean values of the laser ablation profiles and the previously published bulk data and 25 (89%) of the teeth display less than a 0.2% discrepancy. By calculating linear and polynomial trendlines for each ablated tooth, it was possible to illustrate a strong correlation for the transition pattern between the measurements when following a chronological sequence from the tip to the cervix. Such correlations were not reproduced when the data sequence was randomized. The analyses show that the chronologically sequenced ablation data fit with a transition between local bioavailable strontium regions, that the measurements do not fluctuate between extremes and that their values are not caused by end-member mixing. This indicates an increasing data resolution when reducing strontium isotope ratio averaging time by minimizing the sampling area. The results suggest strontium incorporation in human teeth can be measured on an ordinal scale, with a traceable chronological order to enamel mineralization when sampled from tip to cervix at an equal distance from the surface. Micro-sampling enamel is considered a valid method to assess prehistoric, but not modern, human mobility; laser ablation technology increases the amount of information obtained from a single tooth while rendering minimal damage to the studied specimen.
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| 37. |
- Boethius, Adam, et al.
(författare)
-
Diachronic forager mobility : untangling the Stone Age movement patterns at the sites Norje Sunnansund, Skateholm and Västerbjers through strontium isotope ratio analysis by laser ablation
- 2022
-
Ingår i: Archaeological and Anthropological Sciences. - : Springer Science and Business Media LLC. - 1866-9557 .- 1866-9565. ; 14:9
-
Tidskriftsartikel (refereegranskat)abstract
- Strontium isotope ratios in human teeth from the three Swedish prehistoric Stone Age hunter-fisher-gathering societies Norje Sunnansund (Maglemose), Skateholm (Ertebølle) and Västerbjers (Pitted Ware Culture) were analysed with laser ablation to produce data on both individual movement patterns and societal mobility trends. The analyses of teeth from both Skateholm and Västerbjers displayed homogeneous ratios and corresponding mobility patterns, while the data from Norje Sunnansund showed larger variances with heterogenous strontium ratios and varied inter-individual mobility patterns. Correlation with the bioavailable baseline suggests that the size of the geographical areas, where human strontium ratios could have originated, was roughly comparable for all three sites. The teeth measurements were reflected within a 50-km radius of the surrounding landscape and the 25–75% data quartile matched with distances between 3 and 30 km from the sites, suggesting limited mobility ranges among aquatically dependent foragers from southernmost Sweden. By applying ethnographic analogies and site-specific contextual inferences, the results suggest that mobility ranges at Norje Sunnansund were likely not delimited by neighbouring group territories. This changed over time and an increasing territorialisation of the landscape may have influenced movement patterns and caused restrictions to the foraging activities at both Skateholm and Västerbjers.
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| 38. |
- Boethius, Adam, et al.
(författare)
-
Early Holocene Scandinavian foragers on a journey to affluence: Mesolithic fish exploitation, seasonal abundance and storage investigated through strontium isotope ratios by laser ablation (LA‐MC-ICP‐MS)
- 2021
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 16:1, s. e0245222-e0245222
-
Tidskriftsartikel (refereegranskat)abstract
- At Norje Sunnansund, an Early Holocene settlement in southern Sweden, the world’s earliest evidence of fermentation has been interpreted as a method of managing long-term and large-scale food surplus. While an advanced fishery is suggested by the number of recovered fish bones, until now it has not been possible to identify the origin of the fish, or whether and how their seasonal migration was exploited. We analysed strontium isotope ratios (87Sr/86Sr) in 16 cyprinid and 8 pike teeth, which were recovered at the site, both from within the fermentation pit and from different areas outside of it, by using laser ablation multi-collector inductively coupled plasma mass spectrometry. Our investigation indicates three different regions of origin for the fish at the site. We find that the most commonly fermented fish, cyprinids (roach), were caught in the autumn during their seasonal migration from the Baltic Sea to the sheltered stream and lake next to the site. This is in contrast to the cyprinids from other areas of the site, which were caught when migrating from nearby estuaries and the Baltic Sea coast during late spring. The pikes from the fermentation pit were caught in the autumn as by-catch to the mainly targeted roach while moving from the nearby Baltic Sea coast. Lastly, the pikes from outside the fermentation pit were likely caught as they migrated from nearby waters in sedimentary bedrock areas to the south of the site, to spawn in early spring. Combined, these data suggest an advanced fishery with the ability to combine optimal use of seasonal fish abundance at different times of the year. Our results offer insights into the practice of delayed-return consumption patterns, provide a more complete view of the storage system used, and increase our understanding of Early Holocene sedentism among northern hunter-fisher-gatherers. By applying advanced strontium isotope analyses to archaeological material integrated into an ecological setting, we present a methodology that can be used elsewhere to enhance our understanding of the otherwise elusive indications of storage practices and fish exploitation patterns among ancient foraging societies.
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| 39. |
- Brechensbauer Brandin, Madeleine, et al.
(författare)
-
Centralen : Studier i området kring Stockholms Centralstation
- 1989
-
Rapport (populärvet., debatt m.m.)abstract
- Denna skrift handlar om Centralen i Stockholm och dess närmaste omgivningar, Centralplan, T-centralen, Vasagatan och Klarabergsgatan. Den är resultatet av Arkitekturskolans arbete läsåret 1983- 84 och innehåller förutom en rad projekt också historiska utblickar och samtidskritiska resonemang. En stor del av innehållet redovisades redan våren 1984 - det skedde genom en utställning på Arkitekturmuseet och en preliminär publikation. Materialet har sedan svällt ut med innehållsrika uppsatser om Centralen, om äldre och nyare insatser för att förena konst och arkitektur och om den föga kända, ännu obebyggda Blekholmen.
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| 40. |
- Bruce, Carl, et al.
(författare)
-
Preparation and evaluation of a block copolymer compatibilizer for biocomposite applications
- 2012
-
Konferensbidrag (refereegranskat)abstract
- In this study, the concept of using a free polymer as a compatibilzer in biocomposite applications has been evaluated with focus on the polymer poly(ɛ-caprolactone) (PCL), commonly used in conventional grafting onto/from cellulose. A block copolymer consisting of PCL and a shorter segment of poly(di(methylamino)ethyl methacrylate) (PDMAEMA) was made combining ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). The length of the PDMAEMA-part was kept constant, and the PCL-part was varied in three different lengths, yielding three separate block copolymers. As a final step, the PDMAEMA-part was quaternized, which resulted in cationically charged chains –polyelectrolytes. The charged part could then be used as an electrostatic linker allowing the PDMAEMA-PCL copolymer to be adsorbed onto negatively charged cellulose model surfaces. Finally, these cellulose model surfaces were evaluated regarding for example amount of polymer adsorbed and hydrophobic character, investigated with techniques such as quartz crystal microbalance (QCM) and contact angle measurements.
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| 41. |
- Bäck, Henry, 1947, et al.
(författare)
-
Den svenska politiken : Struktur, processer och resultat
- 2006
-
Bok (övrigt vetenskapligt/konstnärligt)abstract
- I Den svenska politiken ges en bred översikt över statsskicket och politiken. Med utgångspunkt i stats- och samhällsvetenskaplig forskning beskrivs och analyseras staten, EU, kommuner och landsting. Det politiska systemet gör det möjligt att fatta gemensamma beslut och skrida till gemensam handling i samhället. Till skillnad från andra system för gemensamt handlande verkar politiken genom att använda makt. För att kunna fånga maktutövningen i ett politiskt system krävs analytiska instrument i form av samhällsvetenskaplig teori. I boken behandlas särskilt det politiska systemets inbyggda kontrollmekanismer och den politiska processen. Formandet av den offentliga politiken illustreras med några centrala politikområden i den moderna svenska politiken. Här beskrivs och analyseras både det formella normativa ramverket och ”hur det verkligen går till”. För att begripa dagens svenska politik behöver vi kunna göra jämförelser i både tid och rum, och därför anläggs ett historiskt perspektiv och görs utblickar på andra länder.
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| 42. |
- Bäck, Henry, et al.
(författare)
-
Den svenska politiken : Strukturer, processer och resultat
- 2011. - 3
-
Bok (övrigt vetenskapligt/konstnärligt)abstract
- I boken ges en bred översikt över statsskicket och politiken. Med utgångspunkt i stats- och samhällsvetenskaplig forskning beskrivs och analyseras staten, EU, kommuner och landsting. Läs mer Det politiska systemet gör det möjligt att fatta gemensamma beslut och skrida till gemensam handling i samhället. Till skillnad från andra system för gemensamt handlande verkar politiken genom att använda makt. För att kunna fånga maktutövningen i ett politiskt system krävs analytiska instrument i form av samhällsvetenskaplig teori. I boken behandlas särskilt det politiska systemets inbyggda kontrollmekanismer och den politiska processen. Formandet av den offentliga politiken illustreras med några centrala politikområden i den moderna svenska politiken. Här beskrivs och analyseras både det formella normativa ramverket och "hur det verkligen går till". För att begripa dagens svenska politik behöver vi kunna göra jämförelser i både tid och rum, och därför anläggs ett historiskt perspektiv och görs utblickar på andra länder.Stig Montin, docent i statsvetenskap vid Örebro universitet
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| 43. |
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| 44. |
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| 45. |
- Cabric, Sanja, et al.
(författare)
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Islet Surface Heparinization Prevents the Instant-Blood Mediated Inflammatory Reaction in Islet Transplantation
- 2007
-
Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 56:8, s. 2008-2015
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE—In clinical islet transplantation, the instant blood-mediated inflammatory reaction (IBMIR) is a major factor contributing to the poor initial engraftment of the islets. This reaction is triggered by tissue factor and monocyte chemoattractant protein (MCP)-1, expressed by the transplanted pancreatic islets when the islets come in contact with blood in the portal vein. All currently identified systemic inhibitors of the IBMIR are associated with a significantly increased risk of bleeding or other side effects. To avoid systemic treatment, the aim of the present study was to render the islet graft blood biocompatible by applying a continuous heparin coating to the islet surface.RESEARCH DESIGN AND METHODS—A biotin/avidin technique was used to conjugate preformed heparin complexes to the surface of pancreatic islets. This endothelial-like coating was achieved by conjugating barely 40 IU heparin per full-size clinical islet transplant.RESULTS—Both in an in vitro loop model and in an allogeneic porcine model of clinical islet transplantation, this heparin coating provided protection against the IBMIR. Culturing heparinized islets for 24 h did not affect insulin release after glucose challenge, and heparin-coated islets cured diabetic mice in a manner similar to untreated islets.CONCLUSIONS—This novel pretreatment procedure prevents intraportal thrombosis and efficiently inhibits the IBMIR without increasing the bleeding risk and, unlike other pretreatment procedures (e.g., gene therapy), without inducing acute or chronic toxicity in the islets.
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| 46. |
- Daneva (Mitradjieva), Maria, et al.
(författare)
-
A Comparison of Feasible Direction Methods for the Stochastic Transportation Problem
- 2010
-
Ingår i: Computational optimization and applications. - : Springer Science and Business Media LLC. - 0926-6003 .- 1573-2894. ; 46:3, s. 451-466
-
Tidskriftsartikel (refereegranskat)abstract
- The feasible direction method of Frank and Wolfe has been claimed to be efficient for solving the stochastic transportation problem. While this is true for very moderate accuracy requirements, substantially more efficient algorithms are otherwise diagonalized Newton and conjugate Frank–Wolfe algorithms, which we describe and evaluate. Like the Frank–Wolfe algorithm, these two algorithms take advantage of the structure of the stochastic transportation problem. We also introduce a Frank–Wolfe type algorithm with multi-dimensional search; this search procedure exploits the Cartesian product structure of the problem. Numerical results for two classic test problem sets are given. The three new methods that are considered are shown to be superior to the Frank–Wolfe method, and also to an earlier suggested heuristic acceleration of the Frank–Wolfe method.
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| 47. |
- Daneva (Mitradjieva), Maria, et al.
(författare)
-
A Sequential Linear Programming Algorithm with Multi-dimensional Search : Derivation and Convergence
- 2007
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We present a sequential linear programming, SLP, algorithm in which the traditional line-search step is replaced by a multi-dimensional search. The algorithm is based on inner approximations of both the primal and dual spaces, which yields a method which in the primal space combines column and constraint generation. The algorithm does not use a merit function, and the linear programming subproblem of the algorithm differs from the one obtained in traditional methods of this type, in the respect that linearized constraints are taken into account only implicitly in a Lagrangiandual fashion. Convergence to a point that satisfies the Karush-Kuhn-Tucker conditions is established. We apply the new method to a selection of the Hoch-Schittkowski’s nonlinear test problems and report a preliminary computational study in a Matlab environment. Since the proposed algorithmcombines column and constraint generation, it should be advantageous with large numbers of variables and constraints.
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| 48. |
- Dohlmar, Frida, et al.
(författare)
-
An audit of high dose-rate prostate brachytherapy treatment planning at six Swedish clinics
- 2021
-
Ingår i: Journal of Contemporary Brachytherapy. - : TERMEDIA PUBLISHING HOUSE LTD. - 1689-832X .- 2081-2841. ; 13:1, s. 59-71
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: High dose-rate prostate brachytherapy has been implemented in Sweden in the late 1980s and early 1990s in six clinics using the same schedule: 20 Gy in two fractions combined with 50 Gy in 25 fractions with external beam radiation therapy. Thirty years have passed and during these years, various aspects of the treatment process have developed, such as ultrasound-guided imaging and treatment planning system. An audit was conducted, including a questionnaire and treatment planning, which aimed to gather knowledge about treatment planning methods in Swedish clinics. Material and methods: A questionnaire and a treatment planning case (non-anatomical images) were sent to six Swedish clinics, in which high-dose-rate prostate brachytherapy is performed. Treatment plans were compared using dosimetric indices and equivalent 2 Gy doses (EQD(2)). Treatment planning system report was used to compare dwell positions and dwell times. Results: For all the clinics, the planning aim for the target was 10.0 Gy, but the volume to receive the dose differed from 95% to 100%. Dose constraints for organs at risk varied with up to 2 Gy. The dose to 90% of target volume ranged from 10.0 Gy to 11.1 Gy, equivalent to 26.0 Gy EQD(2) and 31.3 Gy EQD(2), respectively. Dose non-homogeneity ratio differed from 0.18 to 0.32 for clinical target volume (CTV) in treatment plans and conformity index ranged from 0.52 to 0.59 for CTV. Conclusions: Dose constraints for the organs at risk are showing a larger variation than that reflected in compared treatments plans. In all treatment plans in our audit, at least 10 Gy was administered giving a total treatment of 102 Gy EQD(2), which is in the upper part of the prescription doses published in the GEC/ESTRO recommendations.
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| 49. |
- Dohlmar, Frida, et al.
(författare)
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Validation of automated post-adjustments of HDR prostate brachytherapy treatment plans by quantitative measures and oncologist observer study
- 2023
-
Ingår i: Brachytherapy. - : Elsevier BV. - 1538-4721 .- 1873-1449. ; 22:3, s. 407-415
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The aim was to evaluate a postprocessing optimization algorithm's ability to improve the spatial properties of a clinical treatment plan while preserving the target coverage and the dose to the organs at risk. The goal was to obtain a more homogenous treatment plan, minimizing the need for manual adjustments after inverse treatment planning. MATERIALS AND METHODS: The study included 25 previously treated prostate cancer pa-tients. The treatment plans were evaluated on dose-volume histogram parameters established clin-ical and quantitative measures of the high dose volumes. The volumes of the four largest hot spots were compared and complemented with a human observer study with visual grading by eight oncologists. Statistical analysis was done using ordinal logistic regression. Weighted kappa and Fleiss' kappa were used to evaluate intra-and interobserver reliability. RESULTS: The quantitative analysis showed that there was no change in planning target volume (PTV) coverage and dose to the rectum. There were significant improvements for the adjusted treatment plan in: V150% and V200% for PTV, dose to urethra, conformal index, and dose nonhomogeneity ratio. The three largest hot spots for the adjusted treatment plan were significantly smaller compared to the clinical treatment plan. The observers preferred the adjusted treatment plan in 132 cases and the clinical in 83 cases. The observers preferred the adjusted treatment plan on homogeneity and organs at risk but preferred the clinical plan on PTV coverage. CONCLUSIONS: Quantitative analysis showed that the postadjustment optimization tool could improve the spatial properties of the treatment plans while maintaining the target coverage.
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| 50. |
- Engelkes, Torbjörn, et al.
(författare)
-
Loyal to the end : Examining the meaning of loyalty among high-ranking military officers
- 2023
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Ingår i: Res Militaris. - 2265-6294. ; 13:3, s. 936-953
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Tidskriftsartikel (refereegranskat)abstract
- Organizations need co-workers who are committed to common goals and that are loyal to the core values of the organization.[1] The conscious fostering of organizational core values is seen as an important tool in creating loyal co-workers and hence an effective organization.[2] Professions with a strong vocational calling such as medicine (Kallin, 2010), the police (Ewin, 1990 ; Foust, 2018) or the military[3] have particular demands on loyalty to certain core values, and individuals are expected to adopt these as their own. However, organizational core values can be contradictive (Billig, 1988) and sometimes in conflict with the individual´s own core values which – when incompatible – can in turn cause severe moral stress and mental illness.[4] This implies a need for clarification about what is expected from members of an organization concerning the objectives and manifestations of core values. In terms of loyalty, the military profession is possibly one of the most demanding, expecting individuals to risk their own lives and to kill other human beings for the benefit of the organizational goals. However, since misplaced loyalty can cause destructive,[5] and unethical behaviour[6] with enormous consequences – especially in the military (Winslow, 1998) – there is a need to be clear about what kind of loyalty behaviour is constructive and vice versa. Although loyalty is a concept that seems to be defined in many different ways, the number of studies of loyalty and its meaning are quite limited - especially in military research.[7] The overall purpose of this study is to broaden understanding of the meaning of loyalty within the military. Because important core values of an organization are set – or strongly influenced[8] – by its leaders,[9] the aim of this study was to explore how high-ranking officers in the Swedish Armed Forces (SAF) give meaning to their own personal experiences of loyalty and to describe possible common patterns within the participant group. [1] Wieseke, Alavi & Habel, 2014.[2] Berghaus & Cartagena, 2013.[3] Huntington, 1985 ; Moskos & Wood, 1988 ; Kirkhaug, 2009 ; Olsthoorn, 2011 ; Beard, 2014.[4] Molendijk, Kramer & Verweij, 2018.[5] Gabriel, 1982 ; Connor, 2010.)[6] Umphress & Bingham, 2011.[7] Olsthoorn, 2011 ; Connor, Andrews, Noack-Lundberg & Wadham, 2019.[8] Larsson, Haerem, Sjöberg, Alvinius & Bakken, 2007.[9] Fergusson & Milliman, 2008 ; Oh, Cho & Lim, 2018.
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