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  • 1.
    Achtel, Christian
    et al.
    Friedrich Schiller University Jena, Germany.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Kostag, Marc
    University of Sao Paulo, Brazil.
    El Seoud, Omar A.
    University of Sao Paulo, Brazil.
    Heinze, Thomas
    Friedrich Schiller University Jena, Germany.
    Surprising Insensitivity of Homogeneous Acetylation of Cellulose Dissolved in Triethyl(n-octyl)ammonium Chloride/Molecular Solvent on the Solvent Polarity2018In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 303, no 5Article in journal (Refereed)
    Abstract [en]

    The homogeneous acetylation of microcrystalline cellulose (MCC) by acetyl chloride and acetic anhydride in triethyl(n-octyl)ammonium chloride (N2228Cl)/molecular solvents (MSs) is investigated. The reaction with both acylating agents shows the expected increase of the degree of substitution (DS) on reaction temperature and time. Under comparable reaction conditions, however, DS is surprisingly little dependent on the MS employed, although the MSs differ in empirical polarity by 7 kcal mol−1 as calculated by use of solvatochromic probes. The empirical polarities of (MCC + N2228Cl + MS) differ only by 0.8 kcal mol−1. The formation a polar electrolyte sheath around cellulose chains presumably contributes to this “leveling-off” of the dependence DS on the polarity of the parent MS employed. N2228Cl recovery and recycling is feasible. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • 2.
    Andersson, Dag
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Tegehall, Per-Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Wetter, Göran
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    The impact of conformal coatings on the environmental protection of PCBassemblies and the reliability of solder joints2018Conference paper (Other academic)
  • 3.
    Bengtsson, Jenny
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Köhnke, Tobias
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Theliander, Hans
    Chalmers University of Technology, Sweden.
    Dry-jet wet-spun lignin-based carbon fibre precursors2018Conference paper (Other academic)
  • 4.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Influence of coaxial cable on response of high-voltage resisitive dividers2017Conference paper (Refereed)
    Abstract [en]

    An effort is pursued by several European National Measurement Institutes to lower the uncertainties in calibration of UHV measuring systems for lightning impulse. To this end, several reference dividers are investigated as regards their accuracy both for amplitude and for time parameters. During these investigations a deterioration of step response was identified when longer coaxial cables were inserted in the measuring circuit. The measured front time T1 was also affected, in one observed case by 2.5 % elongation of front time as another 25 m cable was inserted. Compared to the intention to calibrate front time measurement to better than 5 % uncertainty for front time, this contribution must be well known, or preferably be eliminated. This paper presents the experimental findings from these investigations. The investigated cables included selected coaxial, tri-axial, and cables with a corrugated screen. The effect of cable length was also studied. The influence was first discovered when applying a very fast step (rise-time < 4 ns) to the high voltage arm of a resistive divider and convolution of this step with the time derivative of an ideal lightning impulse with 0.84/60 µs impulse. The calculated output was analysed with IEC 61083 compliant software to evaluate the front time. Subsequently, these analyses have been augmented by additional comparative measurements where two reference dividers were connected to the same impulse generator, and varying the cable length of one of them. The summarized changes in front time calculated for different combinations of cable and impulse voltage dividers are shown and discussed. It is noted that a change in T1 error depends both on length of cable and its type. The results show that non-negligible front time errors may be introduced when the cable length is increased. To support these findings, further tests have been carried out with two reference impulse dividers connected in standard calibration configuration in accordance with IEC 60060-2. One divider was used as reference, while the cable for the other was varied. In this way, the change of error between configurations could be measured. A theoretical study has also been performed, calculating the distortion of a lightning impulse on a coaxial cable. The results agree qualitatively with experiments, but the detailed results show discrepancies that need further investigation.

  • 5.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Hällström, Jari
    VTT-MIKES, Finland.
    Evaluation of step response of transient recorders for lightning impulse2017Conference paper (Refereed)
    Abstract [en]

    High voltage equipment will be subjected to several types of electrical stress during operation. A battery of factory tests is defined to ensure that the equipment will perform satisfactorily in service. One of the crucial tests is to apply a simulated lighting impulse as standardised to a double-exponential impulse with at front time of 1.2 µs (± 30 %) and a time to half value of 50 µs (± 20 %). Although this wave-shape only approximates natural lightning, there is a solid body of experience within industry, proving that reliability of equipment in service is adequately proven by the standard waveform. It is however crucial for consistency of results that the both voltage level and wave-shape are correctly measured. This paper discusses the requirements and performance of the recording instruments used, leaving the properties of high voltage impulse dividers outside the discussion. The requirements for the recording instrument – transient recorder – are given in IEC 61083-1. The standard provides requirements for, and/or tests to verify, that the recorder has moderately fast response, fast settling time, high resolution, linearity under dynamic conditions, high accuracy and reasonably low internal noise. This is partly in contrast to major trends in transient recorder development, where fast sampling and fast step response are prioritized ahead of high accuracy and fast settling without creeping response. We have therefore evaluated several commercially available recorders in order to find one with respectively flat and reasonably fast step response. In this campaign, a proprietary step generator based on the use of a mercury reed relay has been used. Evaluation of this device is submitted to ISH 2017. It has been found that the measured flatness of the step response directly after the step is a good first indicator of the performance of the transient recorder. This is identified in IEC 61083-1 clauses 1.5.2 and 1.5.3, as a requirement on stability of the recorded step from 0.5 T1min to T2max. For lightning impulse this means from 0.42 µs to 60 µs. For approved transient recorders the requirement is to be within 1 %. For reference transient recorders, a limit of not more than 0.5 % should be applied. Further proof of the accuracy of the transient recorder can be achieved by convolution of an ideal waveform with the recorded step response and analysing the resulting curve with lightning impulse parameter software. A third possibility is to make direct calibration of the transient recorder, using a calculable impulse calibrator. Several state-of-art transient recorders have been evaluated and the results show that only a few are suited for measurement of lightning impulse. Also, the variation of the performance between the ranges and channels of one instruments are significantly large. Both direct assessment of step response as well as result of convolution with a theoretical 0.84/50 µs impulse will be reported. The agreement with results obtained with a calculable impulse calibrator will be illustrated.

  • 6.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Nordlund, Mathias
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Characterisationat low voltage of two reference lightning impulse dividers2017Conference paper (Refereed)
    Abstract [en]

    An effort is pursued by several European National Measurement Institutes to lower the uncertainties in calibration of UHV measuring systems for lighting impulse. To this end, several reference dividers are investigated as regards their accuracy both for amplitude and for time parameters. At SP - RISE Research Institutes of Sweden, a 500 kV resistive reference divider has been in use since 2000. Additionally an 800 kV resistive divider is investigated as a possible reference divider for UHV lightning impulse measuring systems. The best uncertainty for the 500 kV reference measuring system is 1 % for voltage amplitude and 3 % for time parameters. The present work aims at lowering these uncertainties by means of better characterisation and evaluation of the possibilities to apply corrections for known errors. The scale factor and dynamic behaviour of a resistive divider can be conveniently determined at low voltage and frequency. Further experiments such as linearity tests and augmented by scientific work is needed to ascertain the performance at high voltage. Step response plays a major role in the characterisation of dividers, and in this work much effort has gone into gathering step responses and evaluating them for various circuit layouts to characterise the variation of the step response due to circuit dimensions and diverse proximity effects. The step applied to the divider is generated by a mercury wetted relay based step generator with an output voltage of 200 V. The step rise-time is a few ns, and thus appreciably faster than the response of the divider. Apart from inspection of the step response itself, evaluation of measurement errors is performed by convolving an ideal curve with the step response of the divider, including its transmission cable. The convolved signal is evaluated with impulse evaluation software and the parameters compared to the ideal input. The difference is a measure of the errors introduced by the divider. This procedure follows IEC 60060-2: 2010.

  • 7.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Nordlund, Mathias
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Meisner, Johann
    Physikalisch-Technische Bundesanstalt PTB, Germany.
    Passon, Stephan
    Physikalisch-Technische Bundesanstalt PTB, Germany.
    Hällström, Jari
    VTT-MIKES, Finland.
    Lehtonen, Tapio
    VTT-MIKES, Finland.
    Characterization of a fast step generator2017Conference paper (Refereed)
    Abstract [en]

    Lighting impulse measurements are made as a matter of routine in high voltage testing of high-voltage electrical equipment. The test is often decisive for acceptance of the equipment under test, and consequently proper and precise calibration of the measuring system is needed. The present work centres on the need to quantify the errors of reference measuring systems for lightning impulse. Scale factor determination at low frequency (or DC) is the starting point for this determination. The extrapolation from this frequency domain to the domain where microsecond pulses must be faithfully captured requires application either of methods in the frequency domain or in the time domain. Radio frequency measurements are only well defined for coaxial structures and at impedances in the range of 50 O or thereabouts, making them difficult to apply to the large structures of high-voltage measuring systems. The converse method in the time domain is to apply a Dirac impulse to the system and calculate the response to an assumed input signal by convolution. A true Dirac pulse is not readily available and in practice the applied pulse is a step voltage, which is then derived with respect to time and convolved with the applied signal to obtain the response of the measuring system. The step generator used for this purpose should have very fast front without oscillations. The intent is to achieve a close approximation of an ideal step function, which when derived with respect to time, yields the impulse response of a tested system. A necessary prerequisite is that the step is much steeper than the lightning impulse, and is flat after the step on times much longer than the impulse. The ideal switch element in such a step generator should have infinite resistance and zero capacitance in the off-state, very fast switching to on-state and very low resistance in on-state. The mercury wetted reed switch has often been used for this purpose since it has good characteristics in all these respects. Few, if any, electronic components exhibit competitive advantages compared to the reed switch. The relative lack of parasitic effects means that it is close to being an ideal device. Based on earlier experiences by the authors, a new design has been developed with focus on electrical screening and coaxial design in order to realise a step generator that works into a high impedance instrument. Considerable work has been performed to characterise the new device with regard to steepness of step and most importantly, to voltage stability after the step. The most demanding part of this work has been to separate the performance of the switch from that of the oscilloscope. Findings indicate that the step rise-time is less than 0.5 ns, and settling to within 0.5 % within 10 ns.

  • 8.
    De Goey, Heleen
    et al.
    RISE, Swerea, IVF. Jönköping University, Sweden.
    Engström, Dan
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Lennartsson, Martin
    Jönköping University, Sweden.
    Linderoth, Henrik
    Jönköping University, Sweden.
    Design Thinking as Facilitator for Sustainable Innovation: Exploring Opportunities at SMEs in the Swedish Wood Products Industry2015In: Proceedings of the 20th International Conference on Sustainable Innovation, 2015Conference paper (Refereed)
    Abstract [en]

    Design thinking (DT) is the application of design practice as an approach to innovate and initiate change. Recently, DT has received increasing attention as an approach to address sustainability challenges. However, this area is less studied. The purpose of this study was to explore how DT could enable small and medium-sized enterprises (SMEs) in the Swedish wood products industry to create more sustainable offers. Various actors from this industry have identified the need to develop sustainable offers, although few discuss how this is realized. Interviews have been conducted with six SMEs to increase understanding on challenges they perceive with developing sustainable products. Current practice is compared to potential benefits of DT described in literature. Three main benefits of DT for SMEs have been identified. It could enable SMEs [1] to redefine the purpose of their offers, [2] to better address needs and [3] to address conflicting requirements regarding sustainability.

  • 9.
    Englund, Maja
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Agrifood and Bioscience.
    Ulinder, Elin
    RISE - Research Institutes of Sweden, Bioscience and Materials, Agrifood and Bioscience.
    Funktion hos markbaserade reningsanläggningari fält, komplettering2019Report (Other academic)
    Abstract [en]

    This project, Function in small on-site soil and infiltration beds for wastewater treatment in field – competition, investigated the status of small on-site soil treatment systems (STS) for wastewater in field. The project is an extension of a former project, “Function in small on-site soil and infiltration beds for wastewater treatment in field” where 101 were inspected. Together with 56 inspections from this project there were a total of 157 filed inspections.

    The purpose of the study was to find out if there were any common problems in STS and to suggest if they could be prevented. This after that several projects pointed out the occurrence of functional problems, such as clogging and decreasing purification in STS. This study is a supplement to the prewires project to make the quantity more statistically safe (larger number of measurements) and more representative regarding the different conditions that may exist in Sweden.

    The result shows that 8% of the STS had very high levels of water (≥ 11 cm) and 9% had very high levels of sludge (≥ 5 cm) in the distribution pipes. There are indications of correlations between very high levels of water in the distribution pipe and high water levels in other parts of the plant, which suggest that the plant is not working as it should. High levels of water can also be connected to functional faults that have arisen from the comments observed in the field and noted in field protocols.  For very high levels of sludge, there are some indications of relationships of various malfunctions, however, these connections are not as clear. Slightly high levels of sludge (2–5 cm) and water (3–11 cm) do not seem to have as strong connection with malfunction.

    The study also indicates that greater water-loading installation, e.g. baths larger than 300 liters or water purification filters that rinse large amounts of water, should not be led to the STS, and that it is important that the plant is built according to the size specified in the permit. The statistical analysis carried out in the study also indicates that the age of the plant can be a "natural" cause for very high water levels.

    According to the SGU database, the groundwater levels during the time of inspections were much below normal or below normal (SGU 2018). Based on given criteria in the project, about 7% of the STS in the study did not meet the requirements of one meter between the distribution pipe and the groundwater. Due to unreliable control points for groundwater it was uncertain whether the requirements were met or not for 53% STS. Without a reliable control point, it is difficult to follow up the distance between the distribution pipe and the current groundwater level.

    It is important to remember that the performed inspections only provide a momentary-view of the STS and not the operation of the STS over time. Following some STS over a longer period would give a better picture of the function over time and a better idea of how sludge and water levels can vary in different parts and with different seasons. There are also no studies on how, for example, different levels of sludge and water in distribution pipes affect the purification process in the STS. This needs to be studied in the future to increase knowledge and provide guidance on what measures can be taken in different types of functional problems.

  • 10.
    Evegren, Franz
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Fire safety and FRP composite structures in maritime applications2017In: Proceedings of the Energy, Material & Nanotechnology Meeting on Smart & Multifunctional Material - ENM-SMM, 2017Conference paper (Other academic)
  • 11.
    Evegren, Franz
    RISE - Research Institutes of Sweden.
    Paving the way for lightweight constructions on cruise ships through the LASS-C project2012In: Proceedings of the 2nd International conference on Light Weight Marine Structures, 2012Conference paper (Refereed)
    Abstract [en]

    The LASS-C project, "Lightweight construction of a cruise vessel", expanded the concept of making lightweight structures in SOLAS vessels by considering not only superstructures, glass and internal design, but also elements which are part of the hull girder, affecting the ship's global strength. The existing Panamax cruise ship the Norwegian Gem worked as application case in the project where the uppermost five decks were redesigned in lightweight fibre reinforced polymer composite material. Comparing with the previous design, weight savings calculations showed that about 1 200 tons could be saved in load-bearing structures. FEM simulations showed that the weakening of the global strength from using lightweight structures could be compensated by reinforcing the lower decks, still making the residual weight savings economically interesting. Environmental and economic assessments were carried out from a life cycle perspective, proving the lightweight construction has less impact to surroundings and that additional costs would pay back in 2.5 years. The key issue for building ships in plastic composite, namely fire safety, was addressed by performing a risk assessment in line with the method provided for alternative fire safety design and arrangements in SOLAS II-2/17. A preliminary analysis report for the fire safety design was delivered to the Swedish Flag for approval as part of the project.

  • 12.
    Evegren, Franz
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    proFLASH: Methanol fire detection and extinguishment: SP Rapport 2017:222017Report (Other academic)
    Abstract [en]

    Stricter emission requirements have led to ship operation on low flashpoint fuels, such as liquefied natural gas and methanol. These differ in many ways from traditional fuels (e.g. heavy fuel oil and marine gas oil), but requirements and guidelines for fire detection and extinguishment have been sparse. This was addressed in the proFLASH project, first theoretically and then experimentally. This report documents the experimental part of the project, focusing on methanol, and gives technical guidance for fire detection and extinguishing systems. It was for example concluded that methanol flames exhibit similar radiation to ethanol in the IR spectrum, despite limited observability in the visual spectrum. Approved IR flame detectors (tested against ethanol) are thereby likely suitable to detect methanol fire; tested detectors could even detect fully obstructed methanol fire. The design concentration of carbon dioxide gas fire-extinguishing systems should be increased from 40 % to 55 % to achieve the same safety margin for methanol as for traditional fuels. The primary extinguishing mechanism of a water-based fire-extinguishing system used against methanol is dilution, but almost 90 % water may be necessary for extinguishment. Furthermore, dilution makes the methanol flames increasingly invisible. It is recommended to use alcohol resistant foam injection with fixed water-based extinguishing systems, since this significantly reduces the time required for extinguishment. The effectiveness of the system depends on the foam/water application rate. Hence, a higher discharge rate is more effective and a concealed pool is difficult to extinguish. In different compartment fire test scenarios, water-spray with foam injection was more effective against methanol than water-spray without foam against standardized fuels. High and low pressure water mist performed better than water spray against standardized fuels but worse against methanol (with foam injection).

  • 13.
    Evegren, Franz
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    SP Technology develop next generation of fire-safe island ferries for use between Sweden and Denmark2014In: International Fire Buyer, Vol. 26, no 2, p. 52-53Article in journal (Other (popular science, discussion, etc.))
  • 14.
    Evegren, Franz
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Hertzberg, Tommy
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Fire safety regulations and performance of fibre-reinforced polymer composite ship structures2017In: Journal of Engineering for the Maritime Environment (Part M), ISSN 1475-0902, E-ISSN 2041-3084, Vol. 231, no 1, p. 46-56Article in journal (Refereed)
    Abstract [en]

    This paper presents a procedure for how to relate fire performance of fibre reinforced polymer (FRP) composite structures to the fire safety regulations in SOLAS II-2. It can be used as basis when performing a fire risk assessment to demonstrate that the degree of safety is at least equivalent to that provided by prescriptive requirements. A key issue is that requirements and test methods are based on a use of steel structures, which requires seeking the safety level implied by the regulations. This was demonstrated for the regulations and introduced hazards affecting the growth stage of a fire. The safety implied by regulations was related to fire performance of FRP composite by reference to fire tests involving typical materials and some relevant safety measures. Ignition was described as uncritical whilst the fire growth on an FRP composite surface can be rapid. Flammability requirements are generally not achieved by an untreated panel but different means can be used for protection. A fire protective coating can be used to prevent ignition and sprinkler is effective both for fire prevention and extinguishment on interior and external surfaces. For interior spaces it can be relevant with a coating or thermal insulation also to hinder increased generation of smoke and toxic gases during fire evacuation. In total it is shown that fire hazards during the fire growth stage are manageable and a foundation is lain out for a well-structured fire risk assessment.

  • 15.
    Evegren, Franz
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Rahm, Michael
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Fire protection of FRP composite ship balconies2016In: Proceedings of the 11th International Conference on Sandwich Structures, 2016Conference paper (Refereed)
  • 16.
    Fjellgaard Mikalsen, Ragni
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway. Western Norway University of Applied Sciences, Norway; Otto von Guericke University Magdeburg, Germany.
    Fighting flameless fires: Initiating and extinguishing self-sustainedsmoldering fires in wood pellets2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Smoldering fires represent domestic, environmental and industrial hazards. This flameless form of combustion is more easily initiated than flaming, and is also more persistent and difficult to extinguish. The growing demand for non-fossil fuels has increased the use of solid biofuels such as biomass. This represents a safety challenge, as biomass self-ignition can cause smoldering fires, flaming fires or explosions.

    Smoldering and extinguishment in granular biomass was studied experimentally. The set-up consisted of a cylindrical fuel container of steel with thermally insulated side walls. The container was closed at the bottom, open at the top and heated from below by a hot surface. Two types of wood pellets were used as fuel, with 0.75-1.5 kg samples.

    Logistic regression was used to determine the transition region between non-smoldering and self-sustained smoldering experiments, and to determine the influence of parameters. Duration of external heating was most important for initiation of smoldering. Sample height was also significant, while the type of wood pellet was near-significant and fuel container height was not.

    The susceptibility of smoldering to changes in air supply was studied. With a small gap at the bottom of the fuel bed, the increased air flow in the same direction as the initial smoldering front (forward air flow) caused a significantly more intense combustion compared to the normal set-up with opposed air flow.

    Heat extraction from the combustion was studied using a water-cooled copper pipe. Challenges with direct fuel-water contact (fuel swelling, water channeling and runoff) were thus avoided. Smoldering was extinguished in 7 of 15 cases where heat extraction was in the same range as the heat production from combustion. This is the first experimental proof-of-concept of cooling as an extinguishment method for smoldering fires.

    Marginal differences in heating and cooling separated smoldering from extinguished cases; the fuel bed was at a heating-cooling balance point. Lower cooling levels did not lead to extinguishment, but cooling caused more predictable smoldering, possibly delaying the most intense combustion. Also observed at the balance point were pulsating temperatures; a form of long-lived (hours), macroscopic synchronization not previously observed in smoldering fires.

    For practical applications, cooling could be feasible for prevention of temperature escalation from self-heating in industrial storage units. This study provides a first step towards improved fuel storage safety for biomass. 

  • 17.
    Fjellgaard Mikalsen, Ragni
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Fire Research Norway. Western Norway University of Applied Sciences, Norway; Otto von Guericke University Magdeburg, Germany.
    Hagen, Bjarne C.
    Western Norway University of Applied Sciences, Norway.
    Frette, Vidar
    Western Norway University of Applied Sciences, Norway.
    Synchronized smoldering combustion2018In: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 121, no 5, p. 50002-p1-50002-p2Article in journal (Refereed)
    Abstract [en]

    Synchronized, pulsating temperatures are observed experimentally in smoldering fires.The entire sample volume (1.8 l) participates in the pulsations (pulse period 2–4 h). The synchronylasts up to 25 h and is followed by a spontaneous transition to either disordered combustion orself-extinguishment. The synchronization is obtained when the fuel bed is cooled to the brink ofextinguishment. Calculations for adiabatic conditions, including heat generation from combustion(nonlinear in temperature) and heat storage in sample (linear in temperature), predict divergingsample temperature. Experimentally, heat losses to surroundings (linear in temperature) preventtemperatures to increase without bounds and lead to pulsations.

  • 18.
    Havunen, Jussi
    et al.
    VTT-MIKES, Finland.
    Hällström, Jari
    VTT-MIKES, Finland.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Bergman, Allan E.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Using deconvolution for correction of non-ideal step response of lightning impulsedigitizers and measurement systems2017Conference paper (Refereed)
    Abstract [en]

    Lightning impulse measurements can be highly influenced by measurement arrangement, characteristics of high voltage divider, digitizer (transient recorder) performance, and algorithms used for parameter evaluation. The main sources of measurement errors are the non-ideal step responses of digitizer and voltage divider. This paper discusses the use of deconvolution to correct for the non-ideal step response of a digitizer, and of a large mixed divider. Correcting the step response of the complete measuring system by one part at a time is desirable because it allows to evaluate the effectiveness of the correction with trustworthy methods. Step response describes the output of a system as function of time when its input changes between two levels infinitely fast. Real life impulse digitizers and impulse voltage dividers have a finite rise time, and the response does not immediately settle to final value. Slow rise time is often the cause of error for front time parameter. Creeping response is often the cause of error for time to half-value parameter. Step response of an instrument can be determined by applying a stable, known direct voltage, which is then shorted to ground by a mercury-wetted relay. The mercury-wetted relay is assumed nearly an ideal switch, which creates almost an ideal voltage step for input of the instrument. Convolving the derivative of the measured step response with an ideal input gives a measure of distortion caused by the non-perfect step response, and conversely deconvolving the measured step response with the measured signal gives the original input signal. This paper presents an FFT-based method for step response correction using deconvolution. Deconvolution is a mathematical process, which is used to reverse the non-ideal effects of measuring instrument on recorded data. Effectiveness of the method is demonstrated by two examples. In the first example, the non-ideal step responses of the different ranges of an impulse digitizer are corrected. Functionality of the step response correction is evaluated by comparing the results against a calculable impulse voltage calibrator. Results showed that the step response correction reduced errors in lightning impulse parameters. Stability of the step response correction was analysed by studying several impulse calibration results that have been performed for the instrument within a year. The second example corrects the response of a 2400 kV impulse voltage divider. The effectiveness of the correction is evaluated by comparing its results to a 400 kV reference divider.

  • 19.
    Kurdve, Martin
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Shahbazi, Sasha
    Mälardalen University, Sweden.
    Wendin, Marcus
    Mälardalen University, Sweden.
    Bengtsson, Cecilia
    Mälardalen University, Sweden.
    Wiktorsson, Magnus
    Mälardalen University, Sweden.
    Amprazis, Pernilla
    Mälardalen University, Sweden.
    Waste Flow Mapping: Handbook (eng.)2017Book (Other academic)
  • 20.
    Lisa, Bolin
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    Rex, Emma
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    Røyne, Frida
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    Norrblom, Hans-Lennart
    RISE - Research Institutes of Sweden, Swerea.
    Hållbarhetsanalys av cirkulära möbelflöden2017Report (Other academic)
    Abstract [sv]

    Denna rapport belyser på vilket sätt den miljömässiga, sociala och ekonomiska hållbarheten för offentliga möbler ändras när man går från linjära till mer cirkulära affärsmodeller. Analyserna utgår ifrån fallstudier av en trästol med stoppad sits, en stol med metallben och stoppad sits, en kontorsstol samt ett möblemangbestående av skrivbord och stol. De miljömässiga effekterna av att sälja dessa produkter i en cirkulär affärsmodell har beräknats med hjälp av livscykelanalys (LCA). Resultaten diskuteras även i förhållande till cirkulära affärsmodellers inverkan på sociala aspekter och ekonomisk hållbarhet.

    Studien visar att miljönyttan med cirkulära affärsmodeller varierar med produkt men också med typ av miljöpåverkan som studeras. Livscykelanalysberäkningar på produkter som studerats inom projektet visar till exempel på minskningar av klimatpåverkan med runt 20-40% när en möbel tillhandahålls med en cirkulär affärsmodell istället för en traditionell linjär. Samtidigt minskade behovet av ingående materialresurser (trä, stål mm) med runt 50%. Utöver livscykelanalyser bör miljöbedömningen av en cirkulär affärsmodell också särskilt beakta användingen av toxiska ämnen. För att kunna arbeta praktiskt med dessa frågor är dokumentation och spårbarhet för möbler och material en viktigt fråga.  

    En cirkulär affärsmodell ger inte med automatik en lägre total miljöpåverkan. Det som spelar störst roll är affärsmodellens förmåga att öka den faktiska livslängden på produkten. Det är också viktigt att möbler fortsatt designas för att materialen ska kunna återvinnas när möbeln inte längre är i bruk, oavsett om de är gjorda för återbruk eller ej. Ökade transporter och lagerhållning som konsekvens av cirkulära affärskoncept har i våra fallstudier liten inverkan på miljöprestandan.   

    Uppskattningsvis finns en potential till besparing om ca 45 000 ton koldioxidekvivalenter årligen – om alla kontorsmöbler som produceras i Sverige i stället skulle säljas enligt cirkulär modell. Detta motsvarar ungefär nytillverkning av 450 000 kontorsstolar (NEPD-467-327-EN, 2016). Det finns dock mycket lite statistik över hur möbler används och när de de facto slängs vilket gör det svårt att säga något om faktiska miljöförbättringar i större skala.

    Hållbarhet är inte bara miljö, utan även ekonomiska och sociala aspekter, såsom livscykelkostnad för kunden eller påverkan på arbetsmiljö och arbetstillfällen. Om cirkulära affärsmodeller blir mer eller mindre ekonomiskt hållbara beror på det aktuella fallet och ur vems perspektiv ekonomin utvärderas. Viktigt att tänka på när man utvärderar cirkulära affärsmodeller är att ta ett livscykelperspektiv på kostnaderna, t.ex. att en kund inte bara beaktar inköpspris utan alla kostnader att införskaffa, inneha, hantera och avyttra sina möbler. Dessa kostnader kommer att påverka om affärsmodellen är lönsam eller inte för de olika aktörerna. Här saknas dock ofta data när det gäller indirekta kostnader och hanteringskostnader.

    Det är troligt att de största miljöeffekterna av cirkulära affärsmodeller kommer av ändrade beteenden kring möbler och möbelköp på sikt - såsom nya kundgrupper för möbler med lång livslängd - samt inspirationseffekt till andra branscher hur cirkulära affärsmodeller kan genomföras i praktiken.

    För att beräkna eller bedöma hållbarheteffekter krävs en mängd data och metodmässiga val. För att miljö- och hållbarhetsanalyser ska kunna användas mer utbrett i möbelbranschen inom tex marknadskommunikation, upphandling eller som underlag för styrmedel, behöver branschen komma överens om gemensamma riktlinjer för hur man ska beräkna och kommunicera effekterna av cirkularitet.  

  • 21.
    Lövberg, Andreas
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Tegehall, Per-Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    The Stress State of BGA Solder Joints Influenced by the Grain Orientations of Neighboring Joints2018Conference paper (Refereed)
  • 22.
    Mari, Luca
    et al.
    Università Cattaneo LIUC, Italy.
    Ehrlich, Charles
    NIST National Institute of Standards and Technology, USA.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Measurement units as quantities of objects or values of quantities: a discussion2018In: Metrologia, ISSN 0026-1394, E-ISSN 1681-7575, Vol. 55, no 5, p. 716-721Article in journal (Refereed)
    Abstract [en]

    Measurement units have historically been defined as quantities (i.e., specific properties) of objects, such as the mass of a particular piece of metal or the length of a particular rod. While the current International System of Units (SI) Brochure endorses this position, the draft 9th SI Brochure proposes to change it, and instead define measurement units as values of quantities. The reason for this proposed change is not provided, but it does not seem plausible that it is related to the redefinition of the SI units in terms of fundamental constants of nature: the very concept of what a unit is does not depend on the concrete way any given unit is defined. This paper is intended to open a discussion of whether measurement units should be defined as quantities or as quantity values, and provides our rationale for maintaining the definition of units as quantities.

  • 23.
    Rahm, Michael
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Evegren, Franz
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Johnson, Erland
    RISE - Research Institutes of Sweden, Built Environment.
    Ringsberg, Jonas
    Chalmers University of Technology, Sweden.
    Structural Fire Integrity Testing of Lightweight Multiple Core Sandwich Structures2017In: Proceedings of the 6th International Conference on Marine Structures - MARSTRUCT. Progress in the Analysis and Design of Marine Structures, 2017, p. 869-878Conference paper (Refereed)
    Abstract [en]

    Lightweight structures become increasingly important to reduce environmental impact and to improve payload/deadweight ratio of ships. Significant weight savings can be accomplished by replacing steel with fiber reinforced polymer (FRP) sandwich panels. An assessment is then necessary to ensure that equivalent fire safety is provided, since the structures are combustible. To support such assessments, this paper presents results from vertically loaded fire resistance tests of two structures: (1) a “conventional” FRP sandwich bulkhead with thermal insulation (providing load carrying fire resistance for 60 minutes) and (2) a multiple core FRP sandwich bulkhead without insulation. Both bulkheads were constructed for and tested with the same design load. The multiple core sandwich bulkhead demonstrated structural fire integrity performance well beyond 60 minutes whilst having a significantly lower structural weight and thickness. The new type of multiple core sandwich structure thus provides great potential, both from a weight-savings and a fire safety perspective.

  • 24.
    Roos, Sandra
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, IVF. Chalmers University of Technology, Sweden.
    Arvidsson, Rickard
    Chalmers University of Technology, Sweden.
    Jönsson, Christina
    RISE - Research Institutes of Sweden, Materials and Production, IVF, Energi och miljö.
    Calculating the toxicity footprint of Swedish clothing consumption2017Conference paper (Refereed)
    Abstract [en]

    One of the major environmental challenges of the textile industry is the emissions of toxic substances during the production of textiles. It is therefore vital that toxicity impact potential is included when calculating the environmental impact of textile products with life cycle assessment (LCA). Generally, toxicity is considered a weak point in LCA, and specifically for LCA of textile products there is a lack of guidance in the literature. This paper shares the experiences from using USEtox 2.0 for calculating the toxicity footprint of Swedish clothing consumption. The most commonly occurring garments, production processes and related toxic emissions were inventoried for the Swedish clothing consumption. The selected case offered the possibility to compare a variety of bio-based as well as synthetic materials and their production processes. The inventoried substances were matched against existing databases for USEtox characterization factors (CF): the USEtox databases and COSMEDE. For the substances that did not have any CF, USEtox 2.0 was used to calculate new CF. The potential contribution to freshwater ecotoxicity from the Swedish clothing consumption was calculated to 7.9 billion CTUe which can be interpreted as 7.9 cubic kilometres of freshwater where 50% of the species in the ecosystem are exposed daily to a concentration above their EC50. It was found that background processes in the life cycle (exhaust gases from fuel combustion, leakage of substances from mining waste etc.) accounted for 5.5 billion CTUe, or 70%. Direct emissions of toxic substances from the foreground processes (dyestuff, solvents, pesticides etc.) accounted for 2.4 billion CTUe, or 30%. It is important to note that there is a considerable amount of uncertainty in these values. An interesting discovery was that the wet treatment (dyeing and finishing) had the largest contribution to freshwater ecotoxicity impact, both regarding background and foreground processes. The cotton fibre production, infamous for its use of pesticides, had only the second largest contribution, followed by the yarn production. The paper concludes that emissions of toxic substances from textile production are an important environmental aspect to include in LCA studies of textile products. The results also contribute to the understanding of the order of magnitude that use and emissions from textile chemicals have in relation to a nations total clothing consumption. Sharing the experiences from the study can facilitate the inclusion of toxic substances in future LCA studies of textiles and other products.

  • 25.
    Werke, Mats
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Wretland, Anders
    GKN Aerospace AB, Sweden.
    Ottosson, Peter
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Holmberg, Jonas
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Machens, Michael
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Semere, Daniel
    KTH Royal Institute of Technology, Sweden.
    Geometric distortion analysis using a combination of the contour method and machining simulation2018In: Procedia CIRP, 2018, p. 1481-1486Conference paper (Refereed)
    Abstract [en]

    During machining the material removal releases residual stresses introduced by previous process steps. This causes geometric machining distortions and thereby high rejection rates and costs. By simulating the process chain it is possible to predict this type of distortions. However, this requires advanced material models and accurate process- and material data for the individual processes. In order to simplify the modelling efforts a methodology that combines the contour method with machining simulation is proposed. The methodology is validated for an aerospace component using deep layer removal X-ray diffraction and CMM measurements. The methodology will improve possibilities to reduce machining distortions. © 2018 The Authors.

  • 26.
    Wikman, Johan
    et al.
    RISE - Research Institutes of Sweden.
    Evegren, Franz
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Rahm, Michael
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Leroux, Jerome
    Bureau Veritas, France.
    Breuillard, Antoine
    Bureau Veritas, France.
    Kjellberg, Mattias
    Stena AB, Sweden.
    Gustin, Lisa
    Stena AB, Sweden.
    Efraimsson, Fredrik
    Stena AB, Sweden.
    Study investigating cost effective measures for reducing the risk from fires on ro-ro passenger ships (FIRESAFE): Appendix: Sensitivity and Uncertainty Analyses2017Report (Other academic)
  • 27.
    Wikman, Johan
    et al.
    RISE - Research Institutes of Sweden.
    Evegren, Franz
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Rahm, Michael
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Leroux, Jerome
    Bureau Veritas, France.
    Breuillard, Antoine
    Bureau Veritas, France.
    Kjellberg, Mattias
    Stena Rederi AB, Sweden.
    Gustin, Lisa
    Stena Rederi AB, Sweden.
    Efraimsson, Fredrik
    Stena Rederi AB, Sweden.
    Breuillard, Antoine
    Bureau Veritas, France.
    Study investigating cost effective measures for reducing the risk from fires on ro-ro passenger ships (FIRESAFE)2017Report (Other academic)
  • 28.
    Ziegler, Friederike
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Agrifood and Bioscience.
    Bergman, Kristina
    RISE - Research Institutes of Sweden, Bioscience and Materials, Agrifood and Bioscience.
    Svensk konsumtion av sjömat - en växande mångfald2017Report (Other academic)
    Abstract [sv]

    Den svenska sjömatsmarknaden har kartlagts i syfte att identifiera och kvantifiera de vanligaste arterna av fisk och skaldjur, eller "sjömat", som säljs och konsumeras i Sverige. Offentlig statistik kring volym av import, export och produktion i fiske och vattenbruk för 2015 har utgjort grunden för analysen och kombinerats till att ge en översiktsbild av vad som säljs och konsumeras i Sverige. Merparten företag i fiskbranschen kontaktades och har levererat både kvantitativa och kvalitativa uppgifter.

    Biodiversiteten i den svenska sjömatsimporten visade sig vara hög och omfatta ett hundratal arter eller artgrupper. Volym och viktigaste ursprungsländer presenteras för dessa. Svensk konsumtion av sjömat domineras inte oväntat av lax, torsk och sill. Mer överraskande var att en kategori bestående av oidentifierade torskfiskar, bl a från tropiska vatten, hamnar så högt som på plats 13. Av varje kategori av sjömat (torskfisk, laxfisk, plattfisk, räka, krabba, musslor, tonfisk) redovisas en del ospecifikt tillhörande "Övrigt". Längre ner på listan hamnar nya importerade, odlade arter som guldsparid, havsabborre, men även fiskade arter som nilabborre, tandnoting och ett antal arter av tonfisk, varav flera är kraftigt överfiskade. Exempelvis konsumerades fyra ton av den akut hotade blåfenade tonfisken i Sverige. De här arterna har etablerat sig på den svenska sjömatsmarknaden på senare år. Runt 15 ton ål konsumeras per år i Sverige, både från svenskt fiske och från import, och även den är akut hotad.

    Den totala svenska sjömatskonsumtionen för 2015 är 109 000 ton filé och skaldjur utan skal, vilket motsvarar 11 kg per person eller runt 25 kg hel fisk per person. Av detta är 60 % vildfångat och 40 % odlat. Cirka en fjärdedel av den totala volymen är certifierad av antingen MSC eller ASC. Närmare 75 % av det vi äter är importerat, medan svenskt fiske står för drygt 20 % och svenskt vattenbruk står för runt 6 %. På grund av osäkerheter i rapporteringen av import och export så är dock dessa siffror något osäkra. Den totala konsumtionen har mellan 2011 och 2015 ökat. Kartläggningen har gett nya insikter om diversiteten i den svenska sjömatskonsumtionen och fördelningen mellan arter, trots de osäkerheter som finns.

    Sjömat har en stor potential som både hälsosam och hållbart producerad mat, och Livsmedelsverket rekommenderar att vi äter fisk och skaldjur 2-3 gånger per vecka. För stora grupper betyder detta att de bör äta mer sjömat. Det har dock stor betydelse vilken typ av sjömat man väljer att äta både för hälsa och miljö. Därför är det viktigt med bra kunskap om vad som konsumeras och var och hur det har producerats.

    Genomgången har gett insyn i vad statistiken kan användas till och vilka osäkerheter som finns. Rapporten ger även en rad förslag på hur statistiken skulle kunna förbättras, både genom att ställa krav på att nuvarande rutiner för datainsamling om handel och konsumtion av sjömat i större utsträckning följs och genom att mer långsiktigt arbeta för att förbättra dessa rutiner.

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