| 1. |
|
|
| 2. |
- Gidhagen, Lars, et al.
(författare)
-
Towards climate services for European cities : Lessons learnt from the Copernicus project Urban SIS
- 2020
-
Ingår i: Urban Climate. - Amsterdam, Netherlands : Elsevier. - 2212-0955. ; 31
-
Tidskriftsartikel (refereegranskat)abstract
- The growing share of Europe's population living in cities makes urban climate change impact assessment and adaptation a critical issue. The urban environment is characterized by its sensitivity to small-scale meteorological, hydrological and environmental processes. These are generally not fully described in climate models, largely because of the models' insufficient spatial resolution. The Urban SIS climate service offers historical and future simulated data downscaled to 1 km × 1 km resolution over selected European metropolitan areas. The downscaled data are subsequently used as input to air quality and hydrological impact models, all made available to users as Essential Climate Variables and Sectoral Impact Indicators through a web portal. This paper presents the Urban SIS climate service and demonstrates its functionality in a case study in Stockholm city, Sweden. Good model performance was attained for intra-city temperature gradients and small-scale precipitation extremes. Less positive results were obtained for large-scale precipitation and hydrology, mainly due to an insufficient domain size in the meteorological and climate modelling, in turn related to the substantial computational requirements. An uncertainty classification approach was developed to aid the interpretation and user application of the data. We hope our lessons learnt will support future efforts in this direction.
|
|
| 3. |
|
|
| 4. |
- Blomqvist, Lars, 1962-, et al.
(författare)
-
Framtidens resurseffektiva KL-trä – en spaning
- 2023
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Korslimmat trä (KL-trä) för byggnadsändamål är en produkt som togs fram i Centraleuropa i mitten av 1990-talet. Syftet med förstudien är att i samverkan utforska förslag för hur en framtida resurseffektivare KL-träprodukt kan utformas. Målet är att ta fram underlag för utveckling och genera en samling kring frågan. Det finns en medvetenhet för de omvärldsfaktorer som påverkar byggandet med KL-trä. Det finns en ökad efterfrågan på trä i byggsektorn och det finns ett dynamiskt tänkesätt för att ersätta betong med KL-trä. Ökad användning av skogsråvara, global uppvärmning och minskad tillgång via begränsningar i skogsbruk väcker frågor. Vilken råvara har vi i framtiden, vilka trädslag och hur ser tillgången ut? Det resulterande materialet har analyserats utifrån de olika perspektiven som representeras av intressentgrupperna i värdekedjan för byggande med KL-trä. Rapporten avslutas med projektidéer som framkom under arbetet med förstudien.
|
|
| 5. |
- Broholm, Christa, et al.
(författare)
-
Epigenome- and Transcriptome-wide Changes in Muscle Stem Cells from Low Birth Weight Men
- 2020
-
Ingår i: Endocrine Research. - : Informa UK Limited. - 0743-5800 .- 1532-4206. ; 45:1, s. 58-71
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Being born with low birth weight (LBW) is a risk factor for muscle insulin resistance and type 2 diabetes (T2D), which may be mediated by epigenetic mechanisms programmed by the intrauterine environment. Epigenetic mechanisms exert their prime effects in developing cells. We hypothesized that muscle insulin resistance in LBW subjects may be due to early differential epigenomic and transcriptomic alterations in their immature muscle progenitor cells. Results: Muscle progenitor cells were obtained from 23 healthy young adult men born at term with LBW, and 15 BMI-matched normal birth weight (NBW) controls. The cells were subsequently cultured and differentiated into myotubes. DNA and RNA were harvested before and after differentiation for genome-wide DNA methylation and RNA expression measurements. After correcting for multiple comparisons (q ≤ 0.05), 56 CpG sites were found to be significantly, differentially methylated in myoblasts from LBW compared with NBW men, of which the top five gene-annotated CpG sites (SKI, ARMCX3, NR5A2, NEUROG, ESRRG) previously have been associated to regulation of cholesterol, fatty acid and glucose metabolism and muscle development or hypertrophy. LBW men displayed markedly decreased myotube gene expression levels of the AMPK-repressing tyrosine kinase gene FYN and the histone deacetylase gene HDAC7. Silencing of FYN and HDAC7 was associated with impaired myotube formation, which for HDAC7 reduced muscle glucose uptake. Conclusions: The data provides evidence of impaired muscle development predisposing LBW individuals to T2D is linked to and potentially caused by distinct DNA methylation and transcriptional changes including down regulation of HDAC7 and FYN in their immature myoblast stem cells.
|
|
| 6. |
- Cassel, Anders, et al.
(författare)
-
On Perception Safety Requirements and Multi Sensor Systems for Automated Driving Systems
- 2020
-
Ingår i: SAE technical paper series. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191. ; 2020-April:April
-
Tidskriftsartikel (refereegranskat)abstract
- One major challenge in designing SAE level 3-5 Automated Driving Systems (ADS) is to define requirements for the perception system that would enable argumentation for safe operation. The safety requirements on the perception system can only be fulfilled through redundancy in the sensor hardware. It is, however, a challenge to specify the redundancy that is required in the sensor system. Safe operation for an ADS is significantly more difficult compared to advanced driver assistance systems (ADAS). The safety argumentation for ADAS typically argues that in case of a failure in the sensor array a fail-silent behavior is acceptable because the human driver can take control of the vehicle back. This argumentation however is not possible when developing level 4 or higher automation. This paper investigates prerequisites for applying a systematic methodology for analyzing redundancy in a multi-sensor system and the relation to a conceptual ADS functional architecture. This analysis must address the complexity that comes with partially overlapping sensor data from different sensors and considers variations in performance and characteristics due to changes in the environmental conditions. The paper introduces the term incomplete redundancy and presents a systematic methodology for analyzing redundancy. The aim is to provide arguments for how several sensors in a system, when appropriately combined, meet an assigned safety requirement on a higher level. Each sensor will then be assigned a certain responsibility and contributes with a sub-set of information. A set of questions of importance to address as a foundation for such a methodology are defined and discussed. The definitions of redundancy and independence between sensors are discussed as well as contract-based functional safety to adapt to different environmental and operating conditions.
|
|
| 7. |
- Dynesius, Mats, et al.
(författare)
-
Bryophyte species composition at the stand scale (1 ha) – Differences between secondary stands half a century after clear-cutting and older semi-natural boreal forests
- 2021
-
Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 428
-
Tidskriftsartikel (refereegranskat)abstract
- A growing proportion of the boreal biome consists of managed even-aged secondary forest stands regenerated after clear-cutting. Many disturbance-intolerant species may not be able to recolonize or reach their original abundance in these stands before the next clear-cutting, potentially causing large-scale biodiversity losses. Boreal bryophytes (mosses and liverworts) include many species intolerant to clear-cutting, and at small spatial scales species richness and occupancy has been shown to remain changed in secondary stands half a century after logging. To assess if such persistent changes occur also at the stand scale, we listed and estimated cover of all bryophyte species in 1-ha plots, comparing 14 secondary stands originating from clear-cutting 40–60 years earlier with 14 older semi-natural stands. The large plots also made it possible to assess differences in occupancy and abundance for more bryophyte species than in previous studies. Species composition differed significantly for both mosses and liverworts, but unlike earlier studies, we could not detect any significant difference between stand types in species numbers. Thirteen species were significantly associated with semi-natural stands and the total cover of liverworts was less than half in secondary stands. Secondary stands had significantly fewer species typically occurring under shady conditions and/or mostly growing on “tree substrates” (dead wood and/or bases and stems of living trees). Ordination analysis further emphasized the importance of shade and suitable deadwood substrates; the among-plot variation in bryophyte species composition was related to amount of coarse deadwood as well as to gradients from shady spruce dominated to open pine dominated stands and from polar- to equator-facing slopes. Besides lack of suitable habitat conditions in secondary stands, dispersal limitation may have caused a colonization time lag for some species. The clear importance of stand scale habitat conditions for bryophyte species composition calls for management adaptions to facilitate life boating and/or recolonization by ensuring availability of shade, coarse decomposing logs, and specific deciduous tree species (Populus, Salix, Sorbus) in secondary stands.
|
|
| 8. |
|
|
| 9. |
- Gustafsson, David, et al.
(författare)
-
Effect of cutting clearance and sandblasting on fatigue of thick CP800 steel sheets for heavy-duty vehicles
- 2022
-
Ingår i: Hot Sheet Metal Forming of High-Performance Steel: proceedings. - : Wissenschaftliche Scripten. ; , s. 315-322
-
Konferensbidrag (refereegranskat)abstract
- Effect from manufacturing processes on fatigue properties of high-strength thick steel sheets have gained increased attention the recent years, due to new demands on the heavy-duty vehicle (HDV) industry to reduce the carbon footprint. The aim of this study is to add knowledge of the effect of shear cutting clearance on the fatigue behaviour of complex phase CP800 thick steel sheets. In addition, sandblasting and its effect on the fatigue properties are studied. Service loads are fluctuating loads acting on chassis component making fatigue an important failure mode. The fatigue strength usually follows the yield strength of the material and hence weight could in theory be saved by using steels of higher strength. However, in the presence of edge defects this relation does not necessarily hold, this leads to large safety factors of the design and under-utilization of the high-strength material. Thus, an increased knowledge about the effect from manufacturing processes on fatigue properties is important for the quest to achieve weight reduction. This is particularly true for thick sheets which, to the best of our knowledge, are less investigated than their thinner counterparts, but of high importance for the HDV development. In this paper, empirical results from fatigue testing of complex phase steel CP800, subjected to punching and trimming, are presented. Results for different cutting clearances are compared as well as the effect of sandblasting. A fast fatigue testing method called Rapid fatigue test based on stiffness evolution is utilized. The results show the improvement obtained by using sandblasting as well as illustrating the effect of different cutting clearances. These results can be used as a guidance for design and production of HDV components, where cutting clearance is set. Furthermore, the results can be used as an input for discussions whether the extra costs associated with sandblasting is motivated or not for components made from high strength, thick steel sheets.
|
|
| 10. |
- Gustafsson, David
(författare)
-
Effect of shear cutting on metal fatigue
- 2024
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lightweighting of automotive and heavy-duty vehicle components is an important task that does not need any further motivation or background. It can be read in a large part of the technical papers in the field. A common approach for finding lighter solutions is to increase the material grade while decreasing the material thickness. Often in combination with design changes. For perfectly smooth components this is not an issue, but when cut edges from manufacturing processes are present the situation changes. One topic to address is that increased material grade often means increased notch and surface damage sensitivity. This has implications both on forming and fatigue. The reason for selecting a higher strength material is to allow for higher stresses in design. It has however been shown that for a given stress level the fatigue performance of a higher strength material could be worse than for a lower strength counterpart if punched holes or trimmed edges are present. This means that in the search of lower weight there is a risk of increasing stresses, and at the same time selecting a material that is less suited to handle this increase. Hence, engineers and developers are put in a position where these effects must be quantified to find the most efficient solution. This quantification is a cumbersome and expensive task, often including a considerable amount of testing. Important sources of fatigue life reduction in this context are the residual stresses in the loading direction and the surface roughness in the cut edge. This thesis aims to present an overview of metal fatigue in the context of shear cut components. Necessary knowledge regarding the shear cutting process is provided along with a description of numerical methods and considerations for process simulations. These findings are then applied to the presented papers where the first introduces a simplified approach for numerical simulation of shear cutting to obtain residual stresses. In this approach the simplification mainly lies in the failure model calibration. The second paper studies the possibility of using the obtained residual stresses together with measured values of surface roughness to quantify fatigue life reduction of shear cut specimens.
|
|
