| 1. |
- Ekberg, Ewacarin, et al.
(författare)
-
Can MRI Observations Predict Treatment Outcome of Lavage in Patients with Painful TMJ Disc Displacement without Reduction?
- 2015
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Ingår i: Journal of Oral & Maxillofacial Research. - : Kaunas University of Medicine. - 2029-283X. ; 30:1
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The purpose of this study was to examine magnetic resonance imaging findings in patients with painful disc displacement without reduction of the temporomandibular joint to determine whether the findings were able to predict treatment outcome of lavage and a control group treated with local anaesthesia without lavage in a short-term: 3-month perspective. MATERIAL AND METHODS: Bilateral magnetic resonance images were taken of 37 patients with the clinical diagnosis of painful disc displacement without reduction. Twenty-three patients received unilateral extra-articular local anaesthetics and 14 unilateral lavage and extra-articular local anaesthetics. The primary treatment outcome defining success was reduction in pain intensity of at least 30% during jaw movement at the 3-month follow-up. RESULTS: Bilateral disc displacement was found in 30 patients. In 31 patients the disc on the treated side was deformed, and bilaterally in 19 patients. Osteoarthritis was observed in 28 patients, and 13 patients had bilateral changes. Thirty patients responded to treatment and 7 did not, with no difference between the two treated groups. In neither the treated nor the contralateral temporomandibular joint did treatment outcome depend on disc diagnosis, disc shape, joint effusion, or osseous diagnoses. Magnetic resonance imaging findings of disc position, disc shape, joint effusion or osseous diagnosis on the treated or contralateral side did not give information of treatment outcome. CONCLUSIONS: Magnetic resonance imaging findings could not predict treatment outcome in patients treated with either local anaesthetics or local anaesthetics and lavage.
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| 2. |
- Nyqvist, Johanna, et al.
(författare)
-
Differences in health related quality of life in the randomised ARTSCAN study; accelerated vs. conventional radiotherapy for head and neck cancer. A five year follow up
- 2016
-
Ingår i: Radiotherapy and Oncology. - : Elsevier BV. - 0167-8140 .- 1879-0887. ; 118:2, s. 335-341
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Health related quality of life (HRQoL) was assessed in the randomised, prospective ARTSCAN study comparing conventional radiotherapy (CF) with accelerated radiotherapy (AF) for head and neck cancer. Material and methods: 750 patients with squamous cell carcinoma (of any grade and stage) in the oral cavity, oro-, or hypopharynx or larynx (except T1-2, NO glottic carcinoma) without distant metastases were randomised to either conventional fractionation (2 Gy/day, 5 days/week in 49 days, total dose 68 Gy) or accelerated fractionation (1.1 + 2.0 Gy/day, 5 days/week in 35 days, total dose 68 Gy). HRQoL was assessed with EORTC QLQ-C30, QLQ-H&N35 and HADS at baseline, at end of radiotherapy (eRT) and at 3 and 6 months and 1, 2 and 5 years after start of treatment. Results: The AF group reported HRQoL was significantly lower at eRT and at 3 months for most symptoms, scales and functions. Few significant differences were noted between the groups at 6 months and 5 years. Scores related to functional oral intake never reached baseline. Conclusion: In comparison to CF, AF has a stronger adverse effect on HRQoL in the acute phase.
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| 3. |
- Zackrisson, Björn, et al.
(författare)
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Mature results from a Swedish comparison study of conventional versus accelerated radiotherapy in head and neck squamous cell carcinoma - The ARTSCAN trial
- 2015
-
Ingår i: Radiotherapy and Oncology. - : Elsevier BV. - 0167-8140 .- 1879-0887. ; 117:1, s. 99-105
-
Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: This report contains the mature five-year data from the Swedish ARTSCAN trial including information on the influence of p16 positivity (p16+) for oropharyngeal cancers. Material and methods: Patients with previously untreated squamous cell carcinoma without distant metastases of the oral cavity, oropharynx, larynx (except T1-2, NO glottic cancers) and hypopharynx were included. Patients were randomised between accelerated fractionation (AF) (1.1 Gy + 2 Gy per day, 5 days/week for 4.5 weeks, total dose 68 Gy) and conventional fractionation (CF) (2 Gy per day, 5 days/week for 7 weeks, total dose 68 Gy). Human papillomavirus (HPV)-associated p16-expression was assessed retrospectively in tumour tissues from patients with oropharyngeal carcinoma. Results: There was no significant difference in loco-regional control (LRC) between AF and CF (log-rank test p = 0.75). LRC at 5 years was 65.5% for AF and 64.9% for CF. Overall survival (OS) was similar in both arms (p = 0.99). The estimated cancer specific survival (CSS) at 5 years was 62.2% (AF) and 63.3% (CF) (p = 0.99). 206 specimens were analysed for p16 with 153 specimens (74%) identified as p16+. P16 status did not discriminate for response to AF vs. CF with regard to LRC, OS or CSS. Patients with p16+ tumours had a statistically significant better overall prognosis compared with p16 tumours. Conclusion: This update confirms the results of the 2-year report. We failed to identify a positive effect resulting from AF with regards to LRC, OS and CSS. The addition of information on the HPV-associated p16 overexpression did not explain this lack of effect.
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| 4. |
- Abrahamsson, Cecilia, et al.
(författare)
-
Masticatory function in patients with dentofacial deformities before and after orthognathic treatment : a prospective, longitudinal, and controlled study
- 2015
-
Ingår i: European Journal of Orthodontics. - : Oxford University Press. - 0141-5387 .- 1460-2210. ; 37:1, s. 67-72
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The aim of this study was to investigate the self-estimated masticatory ability and masticatory performance in patients with dentofacial deformities before and after orthognathic treatment; in comparison to an age- and gender-matched control group. SUBJECTS AND METHODS: The masticatory ability and masticatory performance were evaluated in 121 consecutive patients (treatment group), referred for orthognathic treatment. Eighteen months after treatment, 98 patients (81%) completed a follow-up examination. Masticatory ability was assessed on a visual analog scale, while the masticatory performance was evaluated by a masticatory test using round silicon tablets. Signs and symptoms of temporomandibular disorders (TMD) were registered by a clinical examination and a questionnaire. The control group comprised 56 age- and gender-matched subjects who were examined at baseline. RESULTS: At the baseline examination, the treatment group had a significantly lower masticatory ability and performance compared with the control group. After treatment, the masticatory ability significantly improved in the treatment group and reached the same level as in the control group. The masticatory performance index increased significantly but was still lower than in the control group. Both the masticatory ability and masticatory performance were affected by the number of occlusal contacts during maximal biting pressure and by the self-estimated overall symptoms of TMD. CONCLUSIONS: Patients with dentofacial deformities, corrected by orthognathic treatment, have a significant positive treatment outcome in respect of masticatory ability and masticatory performance. Furthermore, the occlusion and symptoms of TMD have an impact on both masticatory ability and masticatory performance.
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| 5. |
- Baker, Z., et al.
(författare)
-
Questionable effect of lavage for treatment of painful jaw movements at disc displacement without reduction : a 3-year randomised controlled follow-up
- 2015
-
Ingår i: Journal of Oral Rehabilitation. - : John Wiley & Sons. - 1365-2842 .- 0305-182X. ; 42:10, s. 742-750
-
Tidskriftsartikel (refereegranskat)abstract
- The present randomised controlled study compared the 3-year outcome of local anaesthetics with anaesthetics and lavage in patients suffering from painful temporomandibular joint (TMJ) locking. The study included 45 patients referred for treatment of temporomandibular disorders (TMD) to the Department of Orofacial Pain and Jaw Function, Faculty of Odontology, Malmo University, Malmo, Sweden. All patients received a history questionnaire and clinical examination according to the Research Diagnostic Criteria for TMD, panoramic radiographs and magnetic resonance imaging at baseline. Twenty-five patients were randomised to anaesthetics alone and 20 patients to anaesthetics and lavage. Three years after treatment, we sent the 37 patients who were available for follow-up a questionnaire that evaluated pain intensity, physical and emotional functioning, and global improvement. Thirty-four patients responded. The primary outcome was defined as >= 30% pain relief. In an intention-to-treat analysis, 28 of 45 patients (62%) reported >= 30% pain relief at the follow-up. At 3 years, improvement in pain relief, physical functioning, emotional functioning and global improvement differed non-significantly between local anaesthetics and anaesthetics and lavage. Compared with baseline, significant improvements (P < 0.05) in pain intensity, physical functioning, emotional functioning and global changes had occurred in both groups after 3 years. Because outcome measurements in the local anaesthetics and lavage and the local anaesthetics groups differed non-significantly 3 years after treatment of painful TMJ disc displacement without reduction, use of lavage (50 mL saline) has an equivalent effect as local anaesthetics.
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| 6. |
- Brännström, Mats, 1958, et al.
(författare)
-
Livebirth after uterus transplantation.
- 2015
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Ingår i: Lancet. - 1474-547X. ; 385:9968, s. 607-616
-
Tidskriftsartikel (refereegranskat)abstract
- Uterus transplantation is the first available treatment for absolute uterine infertility, which is caused by absence of the uterus or the presence of a non-functional uterus. Eleven human uterus transplantation attempts have been done worldwide but no livebirth has yet been reported.
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| 7. |
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| 8. |
- Daemi, Bita, et al.
(författare)
-
Advanced image analysis verifies geometry performance of micro-milling systems
- 2017
-
Ingår i: Applied Optics. - : OPTICAL SOC AMER. - 1559-128X .- 2155-3165. ; 56:10, s. 2912-2921
-
Tidskriftsartikel (refereegranskat)abstract
- Accurate dimensional measurement of micro-milled items is a challenge and machine specifications do not include operational parameters in the workshop. Therefore, a verification test that shows the machine's overall geometrical performance over its working area would help machine users in the assessment and adjustment of their equipment. In this study, we present an optical technique capable of finding micro-milled features at submicron uncertainty over working areas > 10 cm(2). The technique relies on an ultra-precision measurement microscope combined with advanced image analysis to get the center of gravity of milled cross-shaped features at subpixel levels. Special algorithms had to be developed to handle the disturbing influence of burr and milling marks. The results show repeatability, reproducibility, and axis straightness for three micro-milling facilities and also discovered an unknown 2 mu m amplitude undulation in one of them.
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| 9. |
- Daemi, Bita, 1982-
(författare)
-
Enhanced image analysis, a tool for precision metrology in the micro and macro world
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The need for high speed and cost efficient inspection in manufacturing lineshas led to a vast usage of camera-based vision systems. The performance ofthese systems is sufficient to determine shape and size, but hardly to an accuracylevel comparable with traditional metrology tools. To achieve highprecision shape/position/defect measurements, the camera techniques haveto be combined with high performance image metrology techniques whichare developed and adapted to the manufactured components. The focus ofthis thesis is the application of enhanced image analysis as a tool for highprecision metrology. Dedicated algorithms have been developed, tested andevaluated in three practical cases ranging from micro manufacturing at submicronprecision to meter sized aerospace components with precision requirementsin the 10 μm range.The latter measurement challenge was solved by low cost standard consumerproducts, i.e. digital cameras in a stereo configuration and structured lightfrom a gobo-projector. Combined with high-precision image analysis and anew approach in camera calibration and 3D reconstruction for precise 3Dshape measurement of meter sized surfaces, the achievement was fulfilledand verified by two conventional measurement systems; a high precisioncoordinate measurement machine and a laser scanner.The sub-micron challenge was the implementation of image metrology forverification of micro manufacturing installations within a joint Europeaninfrastructure network, EUMINAfab. The results were an unpleasant surprisefor some of the participating laboratories, but became a big step forwardto improve the dimensional accuracy of the investigated laser micromachining, micro milling and micro-printing systems, since the accuracy ofthese techniques are very difficult to assess.The third high precision metrology challenge was the measurement of longrange,low-amplitude topographic structures on specular (shiny) aerodynamicsurfaces. In this case Fringe Reflection Technique (FRT) was appliedand image analysis algorithms were used to evaluate the fringe deformationas a measure of the surface slopes to obtain high resolution data. The resultwas compared with an interferometric analysis showing height deviation inthe range of tens of micrometers over a lateral extension of several cm.
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| 10. |
- Daemi, Bita, 1982-, et al.
(författare)
-
Lateral performance evaluation of laser micromachining by highprecision optical metrology and image analysis
- 2017
-
Ingår i: Precision engineering. - : Elsevier. - 0141-6359 .- 1873-2372.
-
Tidskriftsartikel (refereegranskat)abstract
- Today several techniques are available for micro-manufacturing. Yet, it is difficult to assess the precisionand lateral X,Y accuracy of these techniques. The available accuracy information is usually based on spec-ifications given by machine suppliers. This information is based on in-house laboratory tests performedby dedicated machine operators and within an adapted environment. In practice, the accuracy is likelyto vary due to environmental conditions, materials and operator skills. In order to check the specifica-tions in realistic environments the EUMINAfab infrastructure consortium initiated a set of independenthigh precision onsite verification tests on different laser micromachining installations. In addition toproviding performance verification, it gave the participating partners real capability information of theirequipment and possibilities to improve machining performance to a higher level. In this study a compre-hensive verification test was designed and carried out by using a high precision metrology method for 2Dmeasurements based on subpixel resolution image analysis. This methodology improved our knowledgeof the capabilities of three laser micromachining installations, and showed that specifications at singlemicron levels are hard to obtain.
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| 11. |
- Ekberg, Johanna, 1987, et al.
(författare)
-
Porosity investigation of yttria-stabilized zirconia topcoats using NMR cryoporometry
- 2017
-
Ingår i: Surface and Coatings Technology. - : Elsevier BV. - 0257-8972. ; 315, s. 468-474
-
Tidskriftsartikel (refereegranskat)abstract
- Axial suspension plasma spraying (ASPS) is a new, innovative plasma spray technique using a feedstockconsisting of fine powder particles suspended in a liquid. With ASPS, thermal barrier coating (TBC) topcoatswith columnar structures have been produced that are built up by fine powder particles. The microstructure consistsof micro-,meso-, and macro-pores. Due to thewide pore size range including nano-porosity it is challengingto measure porosity and pore size distribution in TBC topcoats. However, it is important to characterize the porousstructure as it affects the thermal conductivity. Nuclear magnetic resonance (NMR) cryoporometry is apromising method for performing such measurements because of its capability of measuring pores down tonanometer size and providing information about the pore geometry. The aim of this paper is to introduce NMRcryoporometry as a newcharacterization technique for determining porosity, pore size distribution and pore geometryof TBC topcoats produced by ASPS. The study includes the comparison of two different yttria-stabilizedzirconia topcoats and NMR cryoporometry is complemented by microstructural characterization using scanningelectron microscopy.
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| 12. |
- Ekberg, Johanna, 1987, et al.
(författare)
-
Porosity measurements on heat treated suspension plasma sprayed YSZ coatings using NMR cryoporometry
- 2017
-
Ingår i: International Thermal Spray Conference 2017 Proceedings. - 9783961440009 ; DVS-Berichte Volume 336, s. 308-313
-
Konferensbidrag (refereegranskat)abstract
- Suspension plasma sprayed (SPS) coatings can be produced with fine powder particles and tailor-made porosity.This allows to achieve low thermal conductivity which makes the coatings attractive as e.g. topcoats in thermalbarrier coatings (TBCs). Used in gas turbine applications, the TBCs are exposed to high temperatures which leadsto alterations of the microstructure. To obtain coatings with optimized properties, possible microstructurealterations like closing of pores and opening of cracks have to be taken into account. Hence, in this study, TBCtopcoats consisting of 8 wt.% yttria-stabilized zirconia (YSZ) were heat treated in air at 1150°C and thereafterinvestigated using scanning electron microscopy, X-ray diffraction, and nuclear magnetic resonance (NMR)cryoporometry. For all investigated samples, the porosity decreased as a result of the heat treatment. The finerpores and cracks disappeared and the larger pores grew slightly and achieved a more distinct shape as thematerial seemed to become more compact.
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| 13. |
- Ekberg, Johanna, 1987, et al.
(författare)
-
The Influence of Heat Treatments on the Porosity of Suspension Plasma-Sprayed Yttria-Stabilized Zirconia Coatings
- 2018
-
Ingår i: Journal of Thermal Spray Technology. - : Springer Science and Business Media LLC. - 1059-9630 .- 1544-1016. ; 27:3, s. 391-401
-
Tidskriftsartikel (refereegranskat)abstract
- Suspension plasma-sprayed coatings are produced using fine-grained feedstock. This allows to control the porosity and to achieve low thermal conductivity which makes the coatings attractive as topcoats in thermal barrier coatings (TBCs). Used in gas turbine applications, TBCs are exposed to high temperature exhaust gases which lead to microstructure alterations. In order to obtain coatings with optimized thermomechanical properties, microstructure alterations like closing of pores and opening of cracks have to be taken into account. Hence, in this study, TBC topcoats consisting of 4 mol.% yttria-stabilized zirconia were heat-treated in air at 1150 °C and thereafter the coating porosity was investigated using image analysis (IA) and nuclear magnetic resonance (NMR) cryoporometry. Both IA and NMR cryoporometry showed that the porosity changed as a result of the heat treatment for all investigated coatings. In fact, both techniques showed that the fine porosity decreased as a result of the heat treatment, while IA also showed an increase in the coarse porosity. When studying the coatings using scanning electron microscopy, it was noticed that finer pores and cracks disappeared and larger pores grew slightly and achieved a more distinct shape as the material seemed to become more compact.
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| 14. |
- Ekberg, Kerstin, 1948-, et al.
(författare)
-
Arbetsgivares kostnader, åtgärder och anpassningar för sjuknärvarande och sjukfrånvarande medarbetare : samband med återgång i arbete och produktion
- 2017
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Studien syftade till att undersöka vilka åtgärder arbetsgivare gör för sjukskrivna medarbetare och vilka kostnader arbetsgivare och samhället har i samband med sjuknärvaro och sjukfrånvaro.Totalt 3000 sjukskrivna personer i AFA Försäkrings register med diagnoserna psykiska besvär eller besvär i rörelseorganen fick ett informationsbrev och förfrågan om samtycke till att forskarna skulle få skicka en enkät till deras arbetsledare; 393 sjukskrivna gav samtycke. En webbenkät skickades till dessa arbetsledare. Totalt 198 arbetsledare (50 %) till sjukskrivna personer besvarade enkäten.Resultaten visar att arbetsgivare genomför en rad olika åtgärder och anpassningar när en medarbetare blir sjukskriven. Analyserna visade att dessa åtgärder och anpassningar i viss mån beror på vem den sjukskrivne medarbetaren är. Åtgärder och anpassningar var vanligare för sjukskrivna med psykiska diagnoser, för högutbildade och för sjukskrivna i högkvalificerade yrken. Kvinnor fick i högre grad anpassningar och åtgärder såsom ändrade arbetsuppgifter och psykosocialt stöd jämfört med män.Demografiska faktorer visade sig ha mindre betydelse för om den sjukskrivne återgick i arbete eller ej. Multipla logistiska regressionsanalyser visade att åtgärder och anpassningar på arbetsplatsen hade signifikanta samband med en ökad chans för återgång i arbete. Resultaten visade också att för sjukskrivna medarbetare vars arbetsledare hade tagit många kontakter med andra aktörer, som HR-avdelningen, företagshälsan och/eller Försäkringskassan var sannolikheten lägre att den sjukskrivne medarbetaren återgick i arbete. Arbetsledare tog fler kontakter, om den sjukskrivne medarbetaren hade en psykisk diagnos.Sjuknärvaro och produktionsförlust före, under och efter sjukskrivningen skattades av arbetsledarna. Sammanlagt beräknades produktionsförlusterna till cirka SEK 100 000 per sjukskrivningsfall. Härutöver lägger arbetsgivare tid på att ta kontakter, genomföra åtgärder och anpassningar och organisera om arbetet. Arbetsledare hade mycket oklar eller saknade helt uppfattning om vad tid, åtgärder och anpassningar kostar, varför detta inte har kunnat analyseras närmare. De beräknade genomsnittliga kostnaderna till följd av produktivitetsförluster är således en underskattning av de faktiska kostnaderna för arbetsgivare.Studien visar att arbetsledares kunskap om vad sjuknärvaro och sjukfrånvaro kostar för verksamheten och för samhället är begränsad. En ökad kostnadsmedvetenhet skulle kunna stimulera till att större resurser läggs på att implementera policys för hälsofrämjande åtgärder och att utbilda arbetsledare i att hantera frågor om hälsa och arbetsförmåga på arbetsplatsen.
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| 15. |
- Ekberg, Kristoffer, et al.
(författare)
-
Cycle Beating - An Analysis of the Boundaries During Vehicle Testing
- 2016
-
Ingår i: IFAC PAPERS ONLINE. - : ELSEVIER SCIENCE BV. ; , s. 657-664
-
Konferensbidrag (refereegranskat)abstract
- Todays vehicle industry is strictly controlled by environmental legislations. The vehicle industry is spending much money out reducing the fuel consumption and fulfilling the emission requirements to make sales possible in different regions in the world. Before introducing; a vehicle on the market, it is tested according to standardized driving cycles to specify the vehicle pollutant emissions and fuel consumption. These cycles allow some deviation from the reference vehicle speed during tests, e.g. NEDC allows deviations of +/- 2 km/h and +/- 1 s. This paper uses dynamic programming to find fuel optimal velocity profiles, given the allowed deviations of +/- 2 km/h and +/- 1 s from reference speed during drive cycle test. By taking advantage of the allowed deviation, the fuel consumption can be reduced by up to 16.56 % according to model results, ruoriing NEDC if gear selections are unrestricted (i.e. using automatic gearbox), and up to 5.90 % if changing gears according to the specifications in the drive cycle. Two different optimization goals are investigated, minimum amount of mass fuel consumed and best mileage. (C) 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
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| 16. |
- Ekberg, Kristoffer, et al.
(författare)
-
Development and Analysis of Optimal Control Strategy for Gear Changing Patterns During Acceleration
- 2019
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Ingår i: IFAC PAPERSONLINE. - : ELSEVIER. ; , s. 316-321
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Konferensbidrag (refereegranskat)abstract
- Vehicle speed planning for heavy duty vehicles is a powerful tool to reduce the fuel consumption, and thereby the emissions released from the vehicle. By optimizing a driving mission for lowest possible fuel consumption, while still fulfilling the mission deadlines, the fuel consumption could be reduced over that specific mission. If the vehicle is driven by a combustion engine, the engine efficiency will be dependent on the load and speed requirements from the vehicle. By having a gearbox between the engine and the wheels, the engine operating points could be selected by choosing the appropriate gear. When optimizing gear changes, different model complexities can be used. To solve a gear change problem during acceleration, some key aspects needs to be taken into account, for example the loss of propulsion power when disengaging the clutch, how much clutch slip should be allowed, the time it takes for the gearbox to change the gear. The paper presents a method how to formulate and solve a fuel optimal acceleration of a vehicle, where the gear selections are in focus. The method is used to find which gears that should be used to perform a fuel optimal acceleration to a predefined vehicle speed. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
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| 17. |
- Ekberg, Kerstin, et al.
(författare)
-
Early and Late Return to Work After Sick Leave: Predictors in a Cohort of Sick-Listed Individuals with Common Mental Disorders
- 2015
-
Ingår i: Journal of occupational rehabilitation. - : Springer Verlag (Germany). - 1053-0487 .- 1573-3688. ; 25:3, s. 627-637
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives The study aims to identify individual and workplace factors associated with early return to work (RTW)-defined as within 3 months-and factors associated with later RTW-between 3 and 12 months after being sick-listed-in a cohort of newly sick-listed individuals with common mental disorders. Methods In a prospective cohort study, a cross-sectional analysis was performed on baseline measures of patients granted sick leave due to common mental disorders. A total of 533 newly sick-listed individuals fulfilled the inclusion criteria and agreed to participate. A baseline questionnaire was sent by post within 3 weeks of their first day of certified medical sickness; 354 (66 %) responded. Those who were unemployed were excluded, resulting in a study population of 319 individuals. Sick leave was recorded for each individual from the Social Insurance Office during 1 year. Analyses were made with multiple Cox regression analyses. Results Early RTW was associated with lower education, better work ability at baseline, positive expectations of treatment and low perceived interactional justice with the supervisor. RTW after 3 months was associated with a need to reduce demands at work, and turnover intentions. Conclusions Early RTW among sick-listed individuals with common mental disorders seems to be associated with the individuals need to secure her/his employment situation, whereas later RTW is associated with variables reflecting dissatisfaction with work conditions. No health measures were associated with RTW. The study highlights the importance of considering not only health and functioning, but also workplace conditions and relations at the workplace in implementing RTW interventions.
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| 18. |
- Ekberg, Kristoffer, et al.
(författare)
-
Improving Fuel Economy and Acceleration by Electric Turbocharger Control for Heavy Duty Long Haulage
- 2017
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Ingår i: IFAC PAPERSONLINE. - : ELSEVIER SCIENCE BV. ; , s. 11052-11057
-
Konferensbidrag (refereegranskat)abstract
- Todays vehicle industry is converging more and more to electrification of vehicles, introducing electrical architectures to cooperate side by side with the combustion engine. This paper investigates the potential of using an electric turbocharger in a long haulage application during highway driving. A charge sustainable control strategy is developed, implemented, tuned, and evaluated on a heavy duty truck model. The benefits of using an electrical turbocharger on a heavy duty diesel truck, from a long haulage perspective, are evaluated. By calibrating the implemented controller, long haulage driving routes can be charge sustainable and consume less fuel than a conventional truck with fix turbine geometry, the fuel savings for the simulated case is 0.9%. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
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| 19. |
- Ekberg, Kristoffer, 1990-, et al.
(författare)
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Modeling and Validation of an Open-Source Mean Value Heavy-Duty Diesel Engine Model
- 2018
-
Ingår i: Simulation Notes Europe. - : Simulation Notes Europe (SNE). - 2306-0271 .- 2305-9974. ; 28:4, s. 197-204
-
Tidskriftsartikel (refereegranskat)abstract
- The pursuit of lower fuel consumption and stricter emission legislation has made a simulation- and optimization-based development methodology important to the automotive industry. The keystone in the methodology, is the system model. But for the results obtained using a model to be credible, the model has to be validated. The paper validates an open-source, meanvalue engine model of a 13 liter CI inline 6 cylinder heavyduty engine, and releases it as open-source.
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| 20. |
- Ekberg, Kristoffer, 1990-, et al.
(författare)
-
Optimal Control of Wastegate Throttle and Fuel Injection for a Heavy-Duty Turbocharged Diesel Engine During Tip-In
- 2017
-
Ingår i: Proceedings of the 58th Conference on Simulation and Modelling (SIMS 58) Reykjavik, Iceland, September 25th – 27th, 2017. - : Linköping University Electronic Press. - 9789176854174 ; , s. 317-325
-
Konferensbidrag (refereegranskat)abstract
- The diesel engine remains one of the key components in the global economy, transporting most of the worlds goods. To cope with stricter regulations and the continuous demand for lower fuel consumption, optimization is a key method. To enable mathematical optimization of the diesel engine, appropriate models need to be developed. These are preferably continuously differentiable, in order to be used with a gradient-based optimization solver. Demonstration of the optimization-based methodology is also necessary in order for the industry to adapt it. The paper presents a complete mean value engine model structure, tailored for optimization and simulation purposes. The model is validated using measurements on a heavyduty diesel engine. The validated model is used to study the transient performance during a time-optimal tip-in, the results validate that the model is suitable for simulation and optimization studies.
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| 21. |
- Ekberg, Kristoffer, 1990-, et al.
(författare)
-
The Effect of Pressure Losses on Measured Compressor Efficiency
- 2016
-
Ingår i: Proceedings Of The 9Th Eurosim Congress On Modelling And Simulation, Eurosim 2016, The 57Th Sims Conference On Simulation And Modelling Sims 2016. - : Linköping University Electronic Press. - 9789176853993 ; , s. 251-257
-
Konferensbidrag (refereegranskat)abstract
- While measuring the compressor behavior at different load points in for example a gas stand, the inlet and outlet pressures are not always measured directly before and after the compressor. The friction inside the pipes and the physical piping configuration affect the measured compressor efficiency, due to the induced change of fluid enthalpy. If the measured pressures at the end of the inlet and outlet pipes are not the same as the actual pressure before and after the compressor, the acquired compressor map does not give the right description of it as an isolated component. The main contribution of this paper is the analysis of the impact of gas stand energy losses due to pipe friction on the compressor map. As a result the paper suggests a way to take the pressure losses in the inlet and outlet pipes into account. The suggested model takes pipe friction, diffuser, nozzle and pipe bends into account. The potential measurement error in compressor efficiency due to energy losses in the pipes in this experiment is 2.7% (percentage points) at maximum mass flow of air through the compressor.
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| 22. |
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| 23. |
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| 24. |
- Ekberg, Margareta Stigsdotter, et al.
(författare)
-
Ungdomar med missbruksproblem och deras uppfattning om skolproblem
- 2016
-
Ingår i: Nordic Studies in Education. - Bergen : Universitetsforlaget. - 1891-5914 .- 1891-5949. ; 36:4, s. 266-278
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of the article is to highlight school problems of adolescents with alcohol and drug problems in Sweden. Bronfenbrenners social-ecological model has been applied in a quantitative content analysis of 415 interviews in connection with the adolescent’s admission of an outpatient contact. The results show that over a third of the adolescents statements are linked to individual characteristics or abilities, while problems related to the school are 13 percent, interaction with peers to 13 percent, and with the connection to the family of 3 percent. About a third of the statements involve both individual factors and the school, and the interaction between these. An important conclusion is that most of these adolescents are still enrolled in school and that several of the school problems mentioned in the study are changeable and thus possible to remedy through both an educational and social support that promotes their connection to the school.
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| 25. |
- Ekberg, Peter, et al.
(författare)
-
3D precision measurements of meter sized surfaces using low cost illumination and camera techniques
- 2017
-
Ingår i: Measurement science and technology. - : Institute of Physics Publishing (IOPP). - 0957-0233 .- 1361-6501. ; 28:4
-
Tidskriftsartikel (refereegranskat)abstract
- Using dedicated stereo camera systems and structured light is a well-known method for measuring the 3D shape of large surfaces. However the problem is not trivial when high accuracy, in the range of few tens of microns, is needed. Many error sources need to be handled carefully in order to obtain high quality results. In this study, we present a measurement method based on low-cost camera and illumination solutions combined with high-precision image analysis and a new approach in camera calibration and 3D reconstruction. The setup consists of two ordinary digital cameras and a Gobo projector as a structured light source. A matrix of dots is projected onto the target area. The two cameras capture the images of the projected pattern on the object. The images are processed by advanced subpixel resolution algorithms prior to the application of the 3D reconstruction technique. The strength of the method lays in a different approach for calibration, 3D reconstruction, and high-precision image analysis algorithms. Using a 10 mm pitch pattern of the light dots, the method is capable of reconstructing the 3D shape of surfaces. The precision (1 sigma repeatability) in the measurements is < 10 mu m over a volume of 60 x 50 x 10 cm(3) at a hardware cost of similar to 2% of available advanced measurement techniques. The expanded uncertainty (95% confidence level) is estimated to be 83 mu m, with the largest uncertainty contribution coming from the absolute length of the metal ruler used as reference.
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| 26. |
- Ekberg, Peter, et al.
(författare)
-
A new 2D-self-calibration method with large freedom and high-precision performance for imaging metrology devices
- 2015
-
Ingår i: Proceedings of the 15th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2015. - : Elsevier. - 9780956679079 ; , s. 159-160
-
Konferensbidrag (refereegranskat)abstract
- When calibrating 2D (or 3D) metrology systems you need to rely on a traceable artefact for the calibration. However if the system you intend to calibrate has smaller uncertainties than the uncertainty of the reference artefact, the uncertainty of the instrument will be dominated by the artefact and not by the instrument. The only way to reveal the performance of the instrument is then to use self-calibration, i.e. a calibration without any externally verified references, except a 1D traceable measurement between two points on an artefact. Already in 1997, Mikael Raugh developed the rigorous mathematics for self-calibration of a 2D metrology stage, based on a lattice structured artefact. The original method and subsequent later improvements have in common that the problem is solved by using some assumptions regarding the artefact used in the calibration; like that the locations of the marks in the lattice are approximately known. There are also other constrains in the mathematical solution that limits its practical use in the industry. In this paper the application of a new general self-calibration algorithm is presented giving a large freedom to the positioning of the artefact, and also less demands on the 2D-structure on it. Rather than being based on rigorous mathematics requiring very exact positioning of the artefact, our algorithm is using a numerical iterative technique to minimize all overall errors. The algorithm is an enhancement of the self-calibration method already published by P. Ekberg et al. The algorithm has successfully been tested by simulations and by using real data from a white light interference microscope, yielding X, Y precision of few nm. The algorithm has also been used for separating distortions in ordinary low cost camera based systems opening up possibilities for accurate measurements in images. In the latter case the images can be compensated for most errors, like barrel or pin-cushion distortions, as well as perspective effects due to the angle of the camera relative the object.
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| 27. |
- Ekberg, Peter, et al.
(författare)
-
Traceable X,Y self-calibration at single nm level of an optical microscope used for coherence scanning interferometry
- 2018
-
Ingår i: Measurement science and technology. - : IOP PUBLISHING LTD. - 0957-0233 .- 1361-6501. ; 29:3
-
Tidskriftsartikel (refereegranskat)abstract
- Coherence scanning interferometry used in optical profilers are typically good for Z-calibration at nm-levels, but the X,Y accuracy is often left without further notice than typical resolution limits of the optics, i.e. of the order of similar to 1 mu m. For the calibration of metrology tools we rely on traceable artefacts, e.g. gauge blocks for traditional coordinate measurement machines, and lithographically mask made artefacts for microscope calibrations. In situations where the repeatability and accuracy of the measurement tool is much better than the uncertainty of the traceable artefact, we are bound to specify the uncertainty based on the calibration artefact rather than on the measurement tool. This is a big drawback as the specified uncertainty of a calibrated measurement may shrink the available manufacturing tolerance. To improve the uncertainty in X, Y we can use self-calibration. Then, we do not need to know anything more than that the artefact contains a pattern with some nominal grid. This also gives the opportunity to manufacture the artefact in-house, rather than buying a calibrated and expensive artefact. The self-calibration approach we present here is based on an iteration algorithm, rather than the traditional mathematical inversion, and it leads to much more relaxed constrains on the input measurements. In this paper we show how the X, Y errors, primarily optical distortions, within the field of view (FOV) of an optical coherence scanning interferometry microscope, can be reduced with a large factor. By self-calibration we achieve an X, Y consistency in the 175 x 175 mu m(2) FOV of similar to 2.3 nm (1 sigma) using the 50x objective. Besides the calibrated coordinate X, Y system of the microscope we also receive, as a bonus, the absolute positions of the pattern in the artefact with a combined uncertainty of 6 nm (1s) by relying on a traceable 1D linear measurement of a twin artefact at NIST.
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| 28. |
- Eriksson, Lars, 1970-, et al.
(författare)
-
Dynamic Modeling, Simulation and Control of Turbochargers
- 2017
-
Ingår i: Dynamic Modeling, Simulation and Control of Turbochargers. - : Nova Science Publishers, Inc.. - 9781536122398 ; , s. 176-206
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Turbochargers stand for the dominating dynamics in engines and in the design, analysis, and optimization of new engines, it becomes more and more important to analyze system interactions and dynamics. In the development process, modeling, simulation, and optimization have evolved from being used in research to being stan- dard tools for engineers and play an important role in the engine development. To be successful in the process, one needs to both have component models, and methods and tools where system models can be built, analyzed, and optimized. The component models should also have capabilities to extrapolate behavior outside the nominal re- gion since design explorations can go to extreme points while searching for optimal solutions.The first part of the chapter summarizes the compressor and turbine maps and how they can be used in simulation models. A generic model structure for compressors and turbines that fit into an engine modeling and simulation framework is described. Then the Ellipse compressor flow model and the Enthalpy based efficiency model will be described, they have been developed so that they can be integrated in a simulation environment and also used in optimization. Their main features are that they are ca- pable of extrapolating compressor behavior outside the normal range of the map in a physically sane way. In addition to this, a tuning method has been developed that takes a normal manufacturer map and returns all model parameters for compressor flow and efficiency models. Thereafter, compact turbine flow and efficiency models will be described.Then the attention is turned to simulation and optimization applications where compressor models are used. First an engine experiment where compressor surge oc- curs is modelled and used to illustrate the extrapolation capabilities using the models presented. Then the scope is turned to control and optimization of turbocharger opera- tion on an engine, where the focus will be on a VGT controlled diesel engine equipped with EGR. First the steady state mapping of the engine is demonstrated, then optimal control of the turbo operation is investigated using modern computer tools for dynamic optimization.
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| 29. |
- Eriksson, Lars, et al.
(författare)
-
Look-ahead controls of heavy duty trucks on open roads - six benchmark solutions
- 2019
-
Ingår i: Control Engineering Practice. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0967-0661 .- 1873-6939. ; 83, s. 45-66
-
Tidskriftsartikel (refereegranskat)abstract
- A benchmark problem for fuel efficient control of a truck on a given road profile has been formulated and solved. Six different solution strategies utilizing varying degrees of off-line and on-line computations are described and compared. A vehicle model is used to benchmark the solutions on different driving missions. The vehicle model was presented at the IFAC AAC2016 symposium and is compiled from model components validated in previous research projects. The driving scenario is provided as a road slope profile and a desired trip time. The problem to solve is a combination of engine-, driveline- and vehicle-control while fulfilling demands on emissions, driving time, legislative speed, and engine protections. The strength of this publication is the collection of all six different solutions in one paper. This paper is intended to provide a starting point for practicing engineers or researchers who work with optimal and/or model based vehicle control.
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| 30. |
- Fonseca, Lars, 1963-, et al.
(författare)
-
Skolproblematik i relation till ungdomar med missbruksproblem
- 2015
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Skolan har en avgörande betydelse för barns och ungdomars utveckling. Skolmisslyckande har i ett flertal studier visat sig vara en särskilt inflytelserik riskfaktor för utvecklandet av drogmissbruk, kriminalitet och psykisk ohälsa. Omvänt hänger en god anknytning till skolan och goda skolresultat samman med en minskad risk för individuella och psykosociala problem som ung vuxen. Detta paper belyser hur ungdomar med alkohol- och narkotikaproblem uppfattar sin skolproblematik och hur de kan relateras till skola, familjeförhållanden, vänner och till den unge själv.Studien baseras på underlag från uppgifter som har samlats in av Maria-mottagningarna i Stockholm, Göteborg och Malmö och urvalet utgörs av 755 ungdomar som under 2013 påbörjade någon form av behandling på öppenvårdsmottagningarna. Av det empiriska materialet framgår att 433 ungdomar – eller 63 procent – uppger att de har eller har haft skolproblem som påverkat deras närvaro, resultat och/eller trivsel. En kvantitativ innehållsanalys har med stöd av ett socialekologiskt utvecklingsperspektiv samt attributionsteori tillämpats för att skapa kategorier av ungdomarnas utsagor om sina skolproblem.De preliminära resultaten illustrerar hur ungdomar med missbruksproblem tillskriver sig själva eller andra yttre faktorer som orsaker till problem i skolan. Av ungdomarnas utsagor kan 37 procent relateras till individuella faktorer som t.ex. koncentrationssvårigheter, inlärningssvårigheter, fysiska eller psykiska problem samt missbruksproblem. Andelen yttranden som kan kopplas till skolan uppgår till 17 procent, till klasskamraterna 11 procent och till familjen 3 procent. En tredjedel av utsagorna kan hänföras till relationen mellan ungdomarna och skolan i form av skolfrånvaro, motivationsproblematik och otrivsel med skolan.Studien pekar även på ett antal implikationer där skolan lyfts fram som en betydelsefull skyddande faktor mot fortsatta alkohol- och narkotikaproblem, genom att med pedagogiskt och socialt stöd stärka elevers engagemang för skolarbetet parallellt med behandling samt som en möjlighet att återintegrera de ungdomar som hoppat av skolan i förtid.
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| 31. |
- Fröidh, Oskar, et al.
(författare)
-
Färdplan för ökad forskning och innovation inom underhåll av järnvägsfordon
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- KTH, Chalmers och Handelshögskolan vid Göteborgs universitet har av Trafikverket fått uppdraget att ta fram ett dokument om forskningen inom underhåll av järnvägsfordon. Det är föreliggande färdplan som ingår i Trafikverkets satsning Morgondagens depåer. Färdplanen ska ligga till grund för en strategi och förslag på utveckling för kostnadseffektivt fordonsunderhåll med de förutsättningar som råder i Sverige, med avreglering och många aktörer i branschen likväl som speciella klimatförutsättningar. Trafikverket har uppmärksammat att frågor om depåer och fordonsunderhåll inte alltid hanteras på ett bra sätt för att utveckla järnvägssystemet. Tidigare hade Banverket ett sektorsansvar men det avskaffades i och med att Trafikverket bildades. Det behövs dock ett övergripande systemansvar och incitament för att leda processen framåt mot en stabil utveckling genom forskning, utveckling och innovation i den fortsatta omreglering som sker av den svenska järnvägssektorn. Hur kan en effektiv samverkan mellan universitet, näringsliv och offentlig sektor utformas för att bidra till en säker och pålitlig tågtrafik i Sverige? En litteraturgenomgång har genomförts för att visa var den internationella forskningsfronten står. Det tycks dock som att det samlade greppet inom underhåll av järnvägsfordon inte är ett genomarbetat forskningsområde, utan det kan bli ett svenskt ”pionjärområde” där universitet, högskolor och institut i samarbete med branschen kan skapa forskningsresultat och kunskapsutveckling. Denna färdplan föreslår ett antal olika områden som skulle behöva ökad forskning för större kunskap och kompetens. Var ska depåer för person- respektive godsfordon mest effektivt lokaliseras, centralt eller perifert i jämförelse med trafiksystemet och respektive omlopp? Hur ska de utformas mest effektivt med tanke på fordonstyper, reservdelar och personalutnyttjande? Hur ska infrastrukturen till och internt i depåerna utformas för effektivt arbete? Detta ska ske i en avreglerad järnvägssektor med olika operatörer, vagnägare, depåägare samt underhållsleverantörer på olika långa kontrakt. Hur ska detta organiseras på ett stabilt sätt med långsiktig ekonomisk bärkraft för samtliga parter? Arbetet går att dela upp i avhjälpande och förebyggande underhåll; i depå eller mobilt, med säkerhets-, drifts- eller komfortrelaterat underhåll. På vilka olika sätt går det att utvärdera samt utveckla modeller för att prognostisera behovet av underhåll enligt ovan nämnda variabler? Målet är att ta fram vetenskapliga metoder för att effektivisera fordonsunderhåll för järnvägstrafiken på ett optimalt sätt. I färdplanen rekommenderas en strategi för fordonsunderhåll: Trafikverket ska verka för att efterfrågad funktion i det svenska järnvägssystemet uppnås, inkluderande kostnadseffektivt underhåll av både infrastruktur och fordon. Hög driftsäkerhet är attraktivt för resenärer och godskunder och har ett värde och motiverar ett samhällsekonomiskt synsätt på underhåll av järnvägsfordon. Tillståndsövervakning och relaterad prediktering ges en viktigare roll för förebyggande underhåll. Öka synergin mellan infrastruktur- och fordonsbaserad tillståndsövervakning, inte minst av den dynamiska samverkan mellan infrastruktur och fordon. Utred hur ”intelligensen” hos infrastruktur och fordon bäst fördelas och utvecklas för ett mera kostnadseffektivt underhåll av järnvägssystemet. Detta innefattar att man vet vad man skall mäta och att uppmätta storheter kan länkas till framtida nedbrytning av fordon och infrastruktur. Utred flödet och ”flaskhalsar” i dagens system av fordonsunderhåll (kritiska aspekter). Utveckla distinktionen av säkerhetsnödvändigt underhåll och komfortrelaterat underhåll. Verka för tydliga och rimliga ”spelregler” för aktörer inom fordonsunderhåll. Förbättra nätverket bland dessa aktörer, inte minst kring tekniska frågor. Skapa ytterligare incitament för effektivt fordonsunderhåll genom att se över kostnader och intäkter i intressentkedjan mellan de primära kunderna och de som kan åtgärda problemen. Lyft fram goda exempel (best practice) på väl fungerande fordonsunderhåll. Låt universitet och högskolor få en viktig och neutral roll i den kunskapsbaserade utvecklingen. Detta bör ske genom att skapa ett forsknings- utvecklings- och demonstrations (FUD)-program inom området underhåll för järnvägsfordon. I denna färdplan föreslås även ett antal olika forskningsprojekt och -områden som skulle kunna utvecklas i ett sammanhållet forskningsprogram.
|
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| 32. |
- Fröidh, Oskar, et al.
(författare)
-
Färdplan för ökad forskning och innovation inom underhåll av järnvägsfordon
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- KTH, Chalmers och Handelshögskolan vid Göteborgs universitet har av Trafikverket fått uppdraget att ta fram ett dokument om forskningen inom underhåll av järnvägsfordon. Det är föreliggande färdplan som ingår i Trafikverkets satsning Morgondagens depåer. Färdplanen ska ligga till grund för en strategi och förslag på utveckling för kostnadseffektivt fordonsunderhåll med de förutsättningar som råder i Sverige, med avreglering och många aktörer i branschen likväl som speciella klimatförutsättningar.Trafikverket har uppmärksammat att frågor om depåer och fordonsunderhåll inte alltid hanteras på ett bra sätt för att utveckla järnvägssystemet. Tidigare hade Banverket ett sektorsansvar men det avskaffades i och med att Trafikverket bildades. Det behövs dock ett övergripande systemansvar och incitament för att leda processen framåt mot en stabil utveckling genom forskning, utveckling och innovation i den fortsatta omreglering som sker av den svenska järnvägssektorn. Hur kan en effektiv samverkan mellan universitet, näringsliv och offentlig sektor utformas för att bidra till en säker och pålitlig tågtrafik i Sverige?En litteraturgenomgång har genomförts för att visa var den internationella forskningsfronten står. Det tycks dock som att det samlade greppet inom underhåll av järnvägsfordon inte är ett genomarbetat forskningsområde, utan det kan bli ett svenskt ”pionjärområde” där universitet, högskolor och institut i samarbete med branschen kan skapa forskningsresultat och kunskapsutveckling.Denna färdplan föreslår ett antal olika områden som skulle behöva ökad forskning för större kunskap och kompetens. Var ska depåer för person- respektive godsfordon mest effektivt lokaliseras, centralt eller perifert i jämförelse med trafiksystemet och respektive omlopp? Hur ska de utformas mest effektivt med tanke på fordonstyper, reservdelar och personalutnyttjande? Hur ska infrastrukturen till och internt i depåerna utformas för effektivt arbete? Detta ska ske i en avreglerad järnvägssektor med olika operatörer, vagnägare, depåägare samt underhållsleverantörer på olika långa kontrakt. Hur ska detta organiseras på ett stabilt sätt med långsiktig ekonomisk bärkraft för samtliga parter? Arbetet går att dela upp i avhjälpande och förebyggande underhåll; i depå eller mobilt, med säkerhets-, drifts- eller komfortrelaterat underhåll. På vilka olika sätt går det att utvärdera samt utveckla modeller för att prognostisera behovet av underhåll enligt ovan nämnda variabler? Målet är att ta fram vetenskapliga metoder för att effektivisera fordonsunderhåll för järnvägstrafiken på ett optimalt sätt.I färdplanen rekommenderas en strategi för fordonsunderhåll:Trafikverket ska verka för att efterfrågad funktion i det svenska järnvägssystemet uppnås, inkluderande kostnadseffektivt underhåll av både infrastruktur och fordon.Hög driftsäkerhet är attraktivt för resenärer och godskunder och har ett värde och motiverar ett samhällsekonomiskt synsätt på underhåll av järnvägsfordon.Tillståndsövervakning och relaterad prediktering ges en viktigare roll för förebyggande underhåll.Öka synergin mellan infrastruktur- och fordonsbaserad tillståndsövervakning, inte minst av den dynamiska samverkan mellan infrastruktur och fordon.Utred hur ”intelligensen” hos infrastruktur och fordon bäst fördelas och utvecklas för ett mera kostnadseffektivt underhåll av järnvägssystemet. Detta innefattar att man vet vad man skall mäta och att uppmätta storheter kan länkas till framtida nedbrytning av fordon och infrastruktur.Utred flödet och ”flaskhalsar” i dagens system av fordonsunderhåll (kritiska aspekter).Utveckla distinktionen av säkerhetsnödvändigt underhåll och komfortrelaterat underhåll.Verka för tydliga och rimliga ”spelregler” för aktörer inom fordonsunderhåll.Förbättra nätverket bland dessa aktörer, inte minst kring tekniska frågor.Skapa ytterligare incitament för effektivt fordonsunderhåll genom att se över kostnader och intäkter i intressentkedjan mellan de primära kunderna och de som kan åtgärda problemen.Lyft fram goda exempel (best practice) på väl fungerande fordonsunderhåll.Låt universitet och högskolor få en viktig och neutral roll i den kunskapsbaserade utvecklingen.Detta bör ske genom att skapa ett forsknings- utvecklings- och demonstrations (FUD)-program inom området underhåll för järnvägsfordon. I denna färdplan föreslås även ett antal olika forskningsprojekt och -områden som skulle kunna utvecklas i ett sammanhållet forskningsprogram.
|
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| 33. |
|
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| 34. |
- Hassellöv, Ida-Maja, 1974, et al.
(författare)
-
Miljörisker sjunkna vrak II. Undersökningsmetoder och miljöaspekter
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- During 2015 the Swedish Maritime Administration continued the second phase of thegovernmental task Environmental risks from sunken wrecks which first report was finalized2014-10-31 (Dnr: 1399-14-01942-6).The main conclusions from the 2014 report remain; for future handling of potentially pollutingshipwrecks it is recommended that the Swedish Agency for Water and Marine Management isgiven a coordinating responsibility in close cooperation with other competent nationalauthorities, such as Swedish Maritime Administration, Swedish Coastguard, Swedish NationalMaritime Museums, the Geological Survey of Sweden, SMHI, Swedish EPA, and SwedishCivil Contingencies Agency. Through coordination of wreck related operations and activitieswithin the concerned competent authorities’ ordinary areas of responsibility, resourceefficiency is improved. The estimated extra cost for implementation of a national strategy forhandling of the wrecks are estimated to be 10-15 MSEK which should be allocated to thecompetent authorities by the Swedish Agency for Water and Marine Management.The conclusions from 2014 was reinforced during 2015, e.g. through the validation of the riskassessment model VRAKA, which is now available in a first operative version. Additionalecotoxicological experiments on the development of tolerance against PAHs in meiofauna andmicroorganism communities were conducted in a field study in Brofjorden. The mainconclusions from this work is that comprehensive analyzes of PAHs should include alkylatedPAHs, and that exposure to PAHs over time can lead to tolerance development in ammoniumoxidizing bacteria, at the expense of their ability to perform the essential ecosystem servicenitrification.Continued measurements of the bottom currents were made at the wrecks Villon and Skytteren,and at the dumping area west of Måseskär. Measurement series yielded important informationon how measuring equipment at the wreck can be deployed in an optimized way in futuremonitoring program; to calculate the possible spreading of pollution from a wreck, currentmeasurements should be performed upstream from the wreck site, while sensors for thedetection of, for example, oil should be put into the turbulence downstream of the wreck.The current measurement instruments (RDCP) deployed at the Måseskär dump site was trawledup after only three weeks of measurements, but still gave valuable information on the extensivebottom trawling that resuspend (stir up) sediments. Earlier geochemical surveys have shownsignificantly elevated arsenic concentrations in the area and sediment resuspension greatlyincreased the risk for spread of any contaminants in the area. Trawling is not prohibited in thearea, and the current lack of knowledge regarding potential effects on human health whenconsuming seafood from dump areas calls for reflection upon the suitability of trawling in thearea.In addition to the current measurements Swedish Maritime Administration and the SwedishNavy conducted hydrographic survey with multibeam and side scan sonar and ROVinvestigation of the wrecks in the dumping area at Måseskär. 28 wrecks were found, and ROVinvestigation showed cargo holds with dumped torpedoes or mines and other containers in some SjöfartsverketDnr: 1399-14-01942-156of the wrecks. There is some discrepancy between the previously measured elevated arsenicconcentrations in the Måseskär area and recently presented data from historical archives thatdoes not support the theory that chemical weapons were dumped in the area. However, there isa very good correlation between the dominant current direction in the area, and the highestmeasured arsenic concentrations in the area downstream of the wrecks, suggesting some formof arsenic source in the area.
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| 35. |
- Johansson, Max, et al.
(författare)
-
Time Optimal Turbocharger Testing in Gas Stands with a Known Map
- 2018
-
Ingår i: IFAC PAPERSONLINE. - : ELSEVIER SCIENCE BV. ; , s. 868-875
-
Konferensbidrag (refereegranskat)abstract
- Turbocharger maps are used in design, evaluation and optimization of engine system operation to represent the turbo operation in different scenarios. To construct such a map, the turbo is tested in a gas flow test bench, called gas stand. Turbo testing is a time and resource consuming experimental process. The turbo is tested in a selected number of test points for different turbo rotational speeds, where the temperatures in the turbo have to be stationary when the measurements that constitute the map are acquired. In this paper, optimal control is used to find the most time efficient pattern of test conditions, and the optimal control strategy to traverse between them. A heat transfer model, describing the heat transfer between the compressor, bearing house, and turbine, is presented and validated against measured data. A direct collocation method is used to find time optimal control trajectories between the specified test points in the map. The method objective is to find the least time consuming control strategy which brings the turbo from one test point to the next, while ensuring thermal equilibrium at the final time. The results suggest that this method reduces turbocharger testing time with a factor higher than 60. The improvements can be further increased, with over 70 times, if a traveling salesman problem is solved to find the optimal route through the turbo map. The described method would be able to map a 43 points turbo map in 22 minutes, including a 5 minute warm-up phase. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
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| 36. |
- Langer, Sarka, 1960, et al.
(författare)
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Indoor Air Quality in energy-efficient buildings in Sweden: comparison with the Swedish residential housing stock and new conventional buildings
- 2018
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Ingår i: Proceedings Indoor Air 2018.
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Konferensbidrag (refereegranskat)abstract
- The aim of this study was to compare the indoor air quality in newly built energy-efficient (passive) buildings in Sweden with the Swedish residential housing stock and new conventional buildings. We have used data from our previous publications to calculate Indoor Environmental Index (IEI), which is an average of Indoor Discomfort Index (IDI) that regards temperature and relative humidity, and Indoor Air Pollution Index (IAPI) that regards concentrations of indoor air pollutants. The passive building had significantly worse IEQ than the housing stock (p <0.05). Further disentangling of the partial indexes revealed that the difference was almost entirely caused by low to very low relative humidity in the passive buildings which affected the IDI. It could be speculated that the low relative humidity is coupled to operation of the ventilation systems and air exchange rates. It might be of importance to review the ventilation requirements in the energy-efficient buildings
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| 37. |
- Langer, Sarka, 1960, et al.
(författare)
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Indoor air quality in passive and conventional new houses in Sweden
- 2015
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Ingår i: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 93:P1, s. 92-100
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Tidskriftsartikel (refereegranskat)abstract
- The indoor environment was evaluated in 20 new passive houses and 21 new conventionally built houses during the 2012/2013 and 2013/2014 heating seasons. Temperature, relative humidity (RH), the concentrations of NO2, ozone, formaldehyde, volatile organic compounds (VOC) and viable microbiological flora were measured. Air exchange rates (AER) were estimated from the CO2 concentrations measured in the bedrooms. The median AER was slightly higher in the passive houses than in the conventional ones (0.68 h-1 vs. 0.60 h-1). The median concentrations in the passive and the conventional buildings were 10 and 12μg/m3 for NO2, 9.7 and 11 μg/m3 for ozone, 11 and 16μg/m3 for formaldehyde, and 270 and 150 μg/m3 for TVOC, respectively. Significant differences in the TVOC and formaldehyde concentrations between the two groups of buildings indicated substantial sources of TVOC present in the passive houses, while sources of formaldehyde may have been more pronounced in the conventional houses. In contrast to the passive houses, the indoor microbiological flora indicated possible mould or moisture problems in six (29%) of the conventionally built houses. When compared with the results previously reported for the Swedish housing stock, AERs and NO2 concentrations were significantly higher in both groups of newly built buildings, while formaldehyde concentrations were significantly lower in the passive houses. TVOC concentrations were not significantly different from those reported for the housing stock, although the most abundant individual VOCs were present mostly at higher concentrations in the new buildings.
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| 38. |
- Leek, Viktor, et al.
(författare)
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Development and Usage of a Continuously Differentiable Heavy Duty Diesel Engine Model Equipped with VGT and EGR
- 2017
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Ingår i: SAE Technical Papers 2017-01-0611. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International.
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Konferensbidrag (refereegranskat)abstract
- Today’s need for fuel efficient vehicles, together with increasing engine component complexity, makes optimal control a valuable tool in the process of finding the most fuel efficient control strategies. To efficiently calculate the solution to optimal control problems a gradient based optimization technique is desirable, making continuously differentiable models preferable. Many existing control-oriented Diesel engine models do not fully posses this property, often due to signal saturations or discrete conditions. This paper offers a continuously differentiable, mean value engine model, of a heavy-duty diesel engine equipped with VGT and EGR, suitable for optimal control purposes. The model is developed from an existing, validated, engine model, but adapted to be continuously differentiable and therefore tailored for usage in an optimal control environment. The changes due to the conversion are quantified and presented. Furthermore, it is shown and analyzed how to optimally control the engine in a fuel optimal way under steady-state conditions, and in a time optimal way in a tip-in scenario.
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| 39. |
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| 40. |
- Persson, Jan, et al.
(författare)
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Costs of production loss and primary health care interventions for return-to-work of sick-listed workers in Sweden
- 2015
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Ingår i: Disability and Rehabilitation. - : Informa UK Limited. - 0963-8288 .- 1464-5165. ; 37:9, s. 771-776
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of this study was to investigate, from the perspective of society, the costs of sick leave and rehabilitation of recently sick-listed workers with musculoskeletal disorders (MSD) or mental disorders (MD). Methods: In a prospective cohort study, 812 sick-listed workers with MSD (518) or MD (294) were included. Data on consumption of health care and production loss were collected over six months from an administrative casebook system of the health care provider. Production loss was estimated based on the number of sick-leave days. Societal costs were based on the human capital approach. Results: The mean costs of production loss per person were EUR 5978 (MSD) and EUR 6381 (MD). Health care interventions accounted for 9.3% (MSD) and 8.2% (MD) of the costs of production loss. Corresponding figures for rehabilitation activities were 3.7% (MSD) and 3.1% (MD). Health care interventions were received by about 95% in both diagnostic groups. For nearly half of the cohort, no rehabilitation intervention at all was provided. Conclusions: Costs associated with sick leave were dominated by production loss. Resources invested in rehabilitation were small. By increasing investment in early rehabilitation, costs to society and the individual might be reduced. Implications for Rehabilitation Resources invested in rehabilitation for sick-listed with musculoskeletal and mental disorders in Sweden are very small in comparison with the costs of production loss. For policy makers, there may be much to gain through investments into improved rehabilitation processes for return to work. Health care professionals need to develop rehabilitative activities aiming for return to work, rather than symptoms treatment only.
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| 41. |
- Salvador, Christian Mark, 1989, et al.
(författare)
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Indoor ozone/human chemistry and ventilation strategies
- 2019
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Ingår i: Indoor Air. - : Hindawi Limited. - 1600-0668 .- 0905-6947. ; 29:6, s. 913-925
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to better understand and quantify the influence of ventilation strategies on occupant-related indoor air chemistry. The oxidation of human skin oil constituents was studied in a continuously ventilated climate chamber at two air exchange rates (1 h-1 and 3 h-1 ) and two initial ozone mixing ratios (30 and 60 ppb). Additional measurements were performed to investigate the effect of intermittent ventilation ("off" followed by "on"). Soiled t-shirts were used to simulate the presence of occupants. A time-of-flight-chemical ionization mass spectrometer (ToF-CIMS) in positive mode using protonated water clusters was used to measure the oxygenated reaction products geranyl acetone, 6-methyl-5-hepten-2-one (6-MHO) and 4-oxopentanal (4-OPA). The measurement data were used in a series of mass balance models accounting for formation and removal processes. Reactions of ozone with squalene occurring on the surface of the t-shirts are mass transport limited; ventilation rate has only a small effect on this surface chemistry. Ozone-squalene reactions on the t-shirts produced gas-phase geranyl acetone, which was subsequently removed almost equally by ventilation and further reaction with ozone. About 70% of gas-phase 6-MHO was produced in surface reactions on the t-shirts, the remainder in secondary gas-phase reactions of ozone with geranyl acetone. 6-MHO was primarily removed by ventilation, while further reaction with ozone was responsible for about a third of its removal. 4-OPA was formed primarily on the surfaces of the shirts (~60%); gas-phase reactions of ozone with geranyl acetone and 6-MHO accounted for ~30% and ~10%, respectively. 4-OPA was removed entirely by ventilation. The results from the intermittent ventilation scenarios showed delayed formation of the reaction products and lower product concentrations compared to continuous ventilation.
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| 42. |
- Shi, Bingbing, 1983, et al.
(författare)
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Ionizer Assisted Air Filtration for Collection of Submicron and Ultrafine Particles—Evaluation of Long-Term Performance and Influencing Factors
- 2015
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 49:11, s. 6891-6898
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Tidskriftsartikel (refereegranskat)abstract
- Previous research has demonstrated that unipolar ionization can enhance the filter performance to collect airborne particles, aeroallergens, and airborne microorganisms, without affecting the filter pressure drop. However, there is a lack of research on the long-term system performance as well as the influence of environmental and operational parameters. In this paper, both field and laboratory tests were carried out to evaluate the long-term particle collection efficiency of a synthetic filter of class M6 with and without ionization. The effect of air velocity, temperature, relative humidity, and particle concentration were further investigated in laboratory tests. Results showed that ionization enhanced the filtration efficiency by 40%-units during most of the operation time. When the ionization system was managed by periodically switching the ionizer polarity, the filtration efficiency against PM0.3–0.5 was maintained above 50% during half a year. Furthermore, the pressure drop of the ionizer-assisted M6 filter was 25−30% lower than that of a filter of class F7. The evaluation of various influencing factors demonstrated that (1) air moisture reduced the increase of filtration efficiency; (2) higher upstream particle concentration and air velocity decreased the filtration efficiency; and (3) the air temperature had very limited effect on the filtration efficiency.
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| 43. |
- Su, Rong, 1985-, et al.
(författare)
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Three-dimensional metrology of embedded microfeatures in ceramics by infrared optical coherence tomography – advantages and limitations
- 2015
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Ingår i: The Proceedings of the 11th International Conference and Exhibition on Laser Metrology, Coordinate Measuring Machine and Machine Tool Performance. - : European society for precision engineering & nanotechnology.
-
Konferensbidrag (refereegranskat)abstract
- Advanced printing, structuring, and lamination technologies allow for large-scale and cost-effective manufacturing of multi-layered ceramic micro devices with complex three-dimensional (3D) structures. Infrared (IR) optical coherence tomography (OCT) is a promising technology for rapid, non-contact, high-resolution, and 3D inspection of the microchannels, metal prints, defects, and delaminations embedded in alumina and zirconia ceramic layers at hundreds of micrometres beneath surfaces. In this study the recent progresses of OCT technology for ceramic materials are reviewed, and its advantages and limitations as a metrology tool are evaluated through experiments and Monte Carlo simulations. Several measurement errors of OCT are revealed and the measurement in lateral directions is significantly affected by scattering in the ceramics. Besides of that, two types of image artefacts are found to be present in OCT images due to multiple reflections between neighbouring boundaries and inhomogeneity of refractive index. A wavefront aberration exists in the OCT system with a scanning scheme of two galvo mirrors.
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| 44. |
- Teli, Despoina, 1980, et al.
(författare)
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Indoor Temperature Variations in Swedish Households: Implications for Thermal Comfort
- 2018
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Ingår i: Cold Climate HVAC 2018. CCC 2018. Springer Proceedings in Energy. - Cham : Springer International Publishing. - 9783030006617 ; , s. 835-845
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Konferensbidrag (refereegranskat)abstract
- Everyday thermal environments affect people’s comfort and wellbeing, with extreme conditions affecting human health. A strong focus on avoiding the extremes along with the introduction of tight thermal comfort criteria over the years has led to design strategies and behaviors that promote thermally stable indoor environments. However, recent research has shown that indoor temperature variation has significant health benefits, e.g. it could help tackle diabetes and obesity. These findings suggest that it is important to investigate not just the average temperature levels in households but also their distribution and variation over different periods. In Sweden, indoor temperatures are considered to be on average high and constant due to a combination of the heating provision mechanism and the high building standards compared to other countries. This paper investigates the temperature distributions in Swedish households using detailed 15-minute indoor air temperature measurements from the 2008 BETSI-survey, provided by the Swedish National Board of Housing, Building and Planning (Boverket). Approximately two million measurements from 1306 households taken during two-week periods in winter 2007/08 are used in this investigation. Indoor temperature variation is investigated in two levels: (i) over the 2-week monitoring period and (ii) within-day. Results showed a considerable range in average dwelling temperatures of 9 K, highlighting a substantial variability between homes in heating temperature and most likely in thermal comfort preferences. Regardless the different temperature levels, the majority of dwellings maintain stable thermal conditions, as demonstrated from the very low temperature variations found. Differences in daily temperature patterns were also observed.
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| 45. |
- Teli, Despoina, 1980, et al.
(författare)
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Winter thermal comfort and indoor air quality in Swedish grade school classrooms, as assessed by the children
- 2016
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Ingår i: Proceedings of the 14th International Conference of Indoor Air Quality and Climate Ghent, Belgium July 3-8 2016.
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Konferensbidrag (refereegranskat)abstract
- This paper presents results from a pilot thermal comfort study in five Swedish grade school classrooms in three different buildings during winter 2015/16. The study includes measurements of environmental parameters (air temperature, globe temperature, relative humidity, air speed, CO2) and questionnaire surveys designed to match the children’s cognitive level. The questionnaire includes questions about thermal perception, air quality and air movement, as well as the children’s clothing level. The aim of this study is to investigate whether recently found differences in thermal sensation between children and adults outside the heating season also apply to the winter season. Children’s assessment is compared to the objective measurements during the surveys, to winter design criteria for school classrooms and to comfort temperatures from previous studies. The results agree with the previously found warmer sensation of children compared to adults’ predicted thermal sensation based on the currently used PMV model, although this time the difference is smaller. Regarding air quality, no relationship was found between children’s assessment and CO2 levels.
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