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Sökning: WFRF:(Fredriksson Rikard)

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1.
  • Amin, Khabat, et al. (författare)
  • Analysis of road safety trends 2020 : Management by objectives for road safety work towards the 2020 interim targets
  • 2021
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • The Swedish road safety management is based on the Vision Zero and designated interim targets to track progress towards its achievement. 2020 was the final year for achieving the interim target of halving the number of fatalities between 2007 and 2020, i.e., a maximum of 220 fatalities in 2020. The interim target also specifies that the number of seriously injured in road traffic must be reduced by a quarter. This report describes and analyses the current road safety trends in terms of road safety performance indicators and the numbers of fatalities and seriously injured. As this report is the last for the 2007-2020 interim target period, it can be seen as a final summary of how well the targets were achieved for fatalities and seriously injured and for the safety performance indicators. However, it is also important to remember that the year 2020 coincided with the COVID-19 pandemic, which had a profound impact on virtually the entire society. This affected travel in a number of different ways, and consequently it is impossible to estimate the impact this has had on the outcome in 2020, although it probably has led to a slightly lower outcome. The table below shows starting and final values together with an overview of whether the safety performance indicators have met the 2020 targets.
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2.
  • Boström, Ola, 1963, et al. (författare)
  • Comparison of car seats in low speed rear-end impacts using the BioRID dummy and the new neck injury criterion (NIC).
  • 2000
  • Ingår i: Accident Analysis and Prevention. ; 32:2, s. 321-328
  • Tidskriftsartikel (refereegranskat)abstract
    • Long-term whiplash associated disorders (WAD) 1-3 sustained in low velocity rear-end impacts is the most common disability injury in Sweden. Therefore, to determine neck injury mechanisms and develop methods to measure neck-injury related parameters are of importance for current crash-safety research. A new neck injury criterion (NIC) has previously been proposed and evaluated by means of dummy, human and mathematical rear-impact simulations. So far, the criterion appears to be sensitive to the major car and collision related risk factors for injuries with long-term consequences. To further evaluate the applicability of NIC, four seats were tested according to a recently proposed sled-test procedure. 'Good' as well as 'bad' seats were chosen on the basis of a recently presented disability risk ranking list. The dummy used in the current tests was the Biofidelic Rear Impact Dummy (BioRID). The results of this study showed that NICmax values were generally related to the real-world risk of long-term WAD 1-3. Furthermore, these results suggested that NICmax calculated from sled tests using the BioRID dummy can be used for evaluating the neck injury risk of different car seats.
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3.
  • Boström, Ola, 1963, et al. (författare)
  • Prediction of neck injuries in rear impacts based on accident data and simulations
  • 1997
  • Ingår i: PROCEEDINGS OF THE 1997 INTERNATIONAL IRCOBI CONFERENCE ON THE BIOMECHANICS OF IMPACT. ; , s. 251-264
  • Konferensbidrag (refereegranskat)abstract
    • Whiplash associated disorders, occurring in car accidents, are an increasing problem worldwide. According to real-life data from police records, the struck car's velocity change (delta V) and occupant gender are two of the most important factors related to Abbreviated Injury Scale (AIS) 1 neck injuries. In this study, a new rear-impact ranking of cars based on 4432 police reported accidents is presented. The ranking concerns the relative neck injury risk and compensates for the influences of car weight and gender. Moreover, some important factors influencing the risk of AIS 1 neck injury are proposed. These include: the stiffness, damping and yielding characteristics of the seat back, the muscle response of the occupant, and the delta V of the struck car and acceleration pulse. Using a mathematical model it is shown that the influence from these factors can be explained by a recently proposed neck injury criterion (NIC). This criterion is based on the neck motion at the passage of full neck retraction. The NIC, based on a number of volunteer tests, is analysed and validated. The consequence of injury outcome of an observed overall seat back stiffening is also discussed. In conclusion, for delta V below 20 km/h, real-life data show that the geometry of the head restraint is of minor importance. A seat back with low yielding limit or soft performance may be preferable. Moreover, the new NIC seems to be a good predictor of real-life neck injuries.
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4.
  • Dean, Morgan E., et al. (författare)
  • Assessing the applicability of impact speed injury risk curves based on US data to defining safe speeds in the US and Sweden
  • 2023
  • Ingår i: Accident Analysis and Prevention. - 0001-4575. ; 190
  • Tidskriftsartikel (refereegranskat)abstract
    • Vision Zero is an approach to road safety that aims to eliminate all traffic-induced fatalities and lifelong injuries. To reach this goal, a multi-faceted safe system approach must be implemented to anticipate and minimize the risk associated with human mistakes. One aspect of a safe system is choosing speed limits that keep occupants within human biomechanical limits in a crash scenario. The objective of this study was to relate impact speed and maximum delta-v to risk of passenger vehicle (passenger cars and light trucks and vans) occupants sustaining a moderate to fatal injury (MAIS2+F) in three crash modes: head-on vehicle-vehicle, frontal vehicle–barrier, and front-to-side vehicle-vehicle crashes. Data was extracted from the Crash Investigation Sampling System, and logistic regression was used to construct the injury prediction models. Impact speed was a statistically significant predictor in head-on crashes, but was not a statistically significant predictor in vehicle-barrier or front–to–side crashes. Maximum delta-v was a statistically significant predictor in all three crash modes. A head-on impact speed of 62 km/h yielded 50% (±27%) risk of moderate to fatal injury for occupants at least 65 years old. A head-on impact speed of 82 km/h yielded 50% (±31%) risk of moderate to fatal injury for occupants younger than 65 years. Compared to the impact speeds, the maximum delta-v values yielding the same level of risk were lower within the head-on crash population. A head-on delta-v of 40 km/h yielded 50% (±21%) risk of moderate to fatal injury for occupants at least 65 years old. A head-on delta-v of 65 km/h yielded 50% (±33%) risk of moderate to fatal injury for occupants younger than 65 years. A maximum delta–v value of approximately 30 km/h yielded 50% (±42%) risk of MAIS2+F injury for passenger car occupants in vehicle-vehicle front-to-side crashes. A maximum delta–v value of approximately 44 km/h yielded 50% (±24%) risk of MAIS2+F injury for light truck and van occupants, respectively, in vehicle-vehicle front-to-side crashes.
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5.
  • Develet, Jean-Adrien, et al. (författare)
  • Evaluation of the Biofidelity of the BioRID-II and THOR-NT Anthropomorphic Test Devices under Seatbelt Pre-Pretensioner Loading in Stationary Conditions
  • 2013
  • Ingår i: 2013 Ohio State University Injury Biomechanics Symposium. ; , s. 1-15
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Pre-pretensioners are active and reversible devices that apply light tension to the seatbelt (less than 300N) which pulls road vehicle occupants rearwards and reduce the backset (head-to-head restraint horizontal distance). This action has been found to have the potential to reduce the number of whiplash injuries in rear impacts. However, pre-pretensioners induced a new load case on current Anthropomorphic Test Devices (ATDs) for which they have not been validated. The purpose of this study was to evaluate the biofidelity of two 50th percentile male ATDs (BioRID-II and THOR-NT), under pre-pretensioner loading in a stationary environment. A literature review resulted in three testing positions that either occur frequently (backset exceeding recommendations) or have high injury potential (leaning far forward at the driver and front passenger seats). Experiments comprised six volunteer subjects, the BioRID-II and the THOR-NT. Corridors for the head-neck complex kinematics, and interaction of the subjects with the seatbelt, were generated based on data from the volunteer tests and ATD responses were compared to the corridors in terms of amplitude, peak occurrence and shape. For slight out-of-position cases (backset ~80mm), the THOR-NT was found to be close to relaxed volunteers and the BioRID-II to tense volunteers; both were suitable for pre-pretensioner testing. Although the BioRID-II results were closer to the corridors than the THOR-NT results in the far forward leaning positions, neither showed sufficiently large rearward motions and head rotations to fit the corridors. Furthermore, head rotations were problematic for both ATDs in the three test positions. Therefore, construction changes to both the pelvis and occipital joints are suggested in order to improve the biofidelity of BioRID-II and THOR-NT in far forward leaning positions.
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6.
  • Edland, Rikard, 1990, et al. (författare)
  • Evaluation of NOx-Reduction Measures for Iron-Ore Rotary Kilns
  • 2020
  • Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 34:4, s. 4934-4948
  • Tidskriftsartikel (refereegranskat)abstract
    • The grate-kiln process is employed for sintering and oxidation of iron-ore pellets. In this process, a fuel (typically coal) is combusted with a large amount of excess air in a rotary kiln, and the high air-to-fuel ratio leads to significant NOx formation. The current Article is an assessment of NOx reduction measures that have been tested in pilot-scale and in full-scale by the Swedish iron-ore company Luossavaara-Kiirunavaara Aktiebolag (LKAB). The results show that the scaling between the full-scale kiln and the pilot-scale kiln is crucial, and several primary measures that reduce NOx significantly in pilot-scale achieve negligible reduction in full-scale. In the investigated full-scale kiln, thermal NOx formation is efficiently suppressed and low compared with the NO formation from the fuel-bound nitrogen (especially char-bound nitrogen). Suppressing the NO formation from the char-bound nitrogen is difficult due to the high amounts of excess air, and all measures tested to alter mixing patterns have shown limited effect. Switching to a fuel with a lower nitrogen content is efficient and probably necessary to achieve low NOx emissions without secondary measures. Simulations show that replacing the reference coal with a biomass that contains 0.1% nitrogen can reduce NOx emissions by 90%.
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7.
  • Edland, Rikard, 1990, et al. (författare)
  • Formation of nitrogen oxides in rotary kiln burners: an assessment of pilot scale experiments using gaseous, liquid and solid fuels
  • 2015
  • Ingår i: INFUB 2015.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The combustion process in rotary kilns for iron ore production is associated with high temperatures and large amounts of highly preheated air (λ=5-6). These conditions are favourable for NOx formation. Further, coal is typically the main fuel in the process and the CO2 emissions need to be reduced. Thus, emission control strategies are becoming of increasing importance for this type of industrial processes. The present work studies the formation of NOx during combustion of oil, gas, two coals and different blends of coal and biomass. The paper includes both experimental and modelling work. The experiments were performed in co-operation with LKAB using their pilot scale burner test facility (400 kWfuel), which is able to simulate the conditions of the full-scale process. The model, which is used to interpret the experimental results, is based on detailed reaction kinetics with simplified descriptions of temperature and mixing profiles. The results show that oil and gas flames lead to significantly higher NOx formation than solid fuel flames. In general, the thermal formation route is shown to be an important contributor to NOx formation, i.e. also for the solid fuels.
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8.
  • Edland, Rikard, 1990, et al. (författare)
  • Implications of Fuel Choice and Burner Settings for Combustion Efficiency and NOx Formation in PF-Fired Iron Ore Rotary Kilns
  • 2017
  • Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 31:3, s. 3253-3261
  • Tidskriftsartikel (refereegranskat)abstract
    • The combustion process applied in the grate-kiln process for iron ore pellet production employs air-to-fuel equivalence ratios in the range of 4-6, typically with coal as fuel and high-temperature air (>1000 degrees C) as oxidant. The NOx emissions from these units are in general significantly higher than those in other combustion systems, and the large flows of flue gases make the implementation of secondary measures for NOx control costly. Therefore, it is of importance to investigate NOx. formation under combustion conditions relevant for iron ore production, in order to control the emissions from these units. The present work examines NO formation during the combustion of four pulverized coals, as well as during cofiring with biomass in a pilot-scale kiln (580 kWfuel) based on a two-week experimental campaign. The influence of burner settings was also included in the investigation. Based on the presented experimental results and the results of previous modeling and experimental studies, we suggest that the NOx emissions are mainly the result of a high conversion of fuel-bound nitrogen (fuel-N) to NO. In particular, char-bound nitrogen (char-N) conversion appears to be higher than in conventional pulverized fuel flames, presumably due to the high levels of oxygen present in the char-burnout region. The temperatures in the kiln varied between the test cases, but thermal NO formation is estimated to be of low importance.
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9.
  • Edland, Rikard, 1990, et al. (författare)
  • Scaling of Pulverized-Fuel Jet Flames That Apply Large Amounts of Excess Air - Implications for NOx Formation
  • 2019
  • Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 12:14
  • Tidskriftsartikel (refereegranskat)abstract
    • Measures to reduce nitrogen oxides (NOx) formation in industrial combustion processes often require up-scaling through pilot-scale facilities prior to being implemented in commercial scale, and scaling is therefore an important aspect of achieving lower NOx emissions. The current paper is a combined experimental and modelling study that aims to expand the understanding of constant velocity scaling for industrial jet flames applying high amounts of excess air. These types of flames are found in e.g., rotary kilns for production of iron ore pellets. The results show that, even if the combustion settings, velocity, and temperature profiles are correctly scaled, the concentration of oxygen experienced by the fuel during char combustion will scale differently. As the NO formation from the char combustion is important in these flames, the differences induced by the scaling has important impacts on the efficiencies of the applied primary measures. Increasing the rate of char combustion (to increase the Damköhler number), by using, for  example, smaller-sized particles, in the pilot-scale is recommended to improve scaling.
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10.
  • Fredriksson, Johan, et al. (författare)
  • Packaging Component-Analysis for Reuse
  • 2007
  • Konferensbidrag (refereegranskat)abstract
    • Component-Based Software Engineering (CBSE) promises an improved ability to reuse software which would potentially decrease the development time while also improving the quality of the system, since the components are (re-)used by many. However, CBSE has not been as successful in the embedded systems domain as in the desktop domain, partly because requirements on embedded systems are stricter (e.g. requirements on safety, real-time and minimizing hardware resources). Moreover these requirements differ between industrial domains. Paradoxically, components should be context-unaware to be reusable at the same time as they should be context sensitive in order to be predictable and resource efficient. This seems to be a fundamental problem to overcome before the CBSE paradigm will be successful also in the embedded systems domain. Another problem is that some of the stricter requirements for embedded systems require certain analyses to be made, which may be very complicated and time-consuming for the system developer.This paper describes how one particular kind of analysis, of worst-case execution time, would fit into the CBSE development processes so that the component developer performs some analyses and presents the results in a form that is easily used for component and system verification during system development. This process model is not restricted to worst-case execution time analysis, but we believe other types of analyses could be performed in a similar way.
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