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  • Blomqvist, Per
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport.
    Sandinge, Anna
    RISE - Research Institutes of Sweden, Safety and Transport.
    Experimental evaluation of fire toxicity test methods2018Report (Other academic)
    Abstract [en]

    An experimental evaluation of the most common bench-scale tests methods for fire toxicity was conducted by RISE Fire Research. The background of the work was the on-going discussion in the fire community on the applicability and relevance of these test methods.

    The test methods included in the programme were the ISO/TS 19700 steady-state tube furnace (SSTF), the controlled atmosphere cone calorimeter (CACC), and the EN 45545-2 smoke chamber test (SC). In these tests the production of selected toxic gases was quantitatively analysed using FTIR. Tests for the measurement of toxic gas production were made with eleven different materials used as test specimens, both combustible and non-combustible materials. The materials were commercially available insulation products provided by EURIMA, the sponsor of the project. These materials should not be regarded as typical or fully representative of a product category.

    The evaluation of the results from the different test methods was divided into combustible test specimens and non-combustible test specimens. That was because the test conditions in the first case are greatly influenced by the combustion behaviour of the test specimen, while in the second case the test conditions are more constant.

    A general observation was that there in many cases was correlation between both species composition and level of toxic gas species yields between test methods when the combustion conditions were similar. In cases where yields differed significantly it could in most cases be explained by clear differences in test conditions.

    For combustible materials it was concluded that the SSTF offers the best means for conducting tests at pre-decided and controlled flaming combustion conditions. The CACC does not give steady-state flaming combustion and the influence of vitiation was limited in the tests made. The SC generally accumulates a mixture of gases from both flaming and non-flaming combustion periods in a test, and the yields measured do not in those cases represent any specific combustion stage.

    For non-combustible materials a general observation was that any of the test methods investigated in principle could be used since the influence on the test conditions from the material itself is limited compared to combustible materials. However, there were specific properties and limitations of the different test methods observed that are important to consider.

  • Keucken, Alexander
    et al.
    Vatten och Miljö i Väst (VIVAB), Sweden ; Lund University, Sweden.
    Habagil, Moshe
    Vatten och Miljö i Väst (VIVAB), Sweden.
    Batstone, Damien
    University of Queensland, Australia.
    Arnell, Magnus
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy. Lunds university, Sweden.
    New insights on process performance and stability for anaerobic co-digestion through modelling and population analysis2018Conference paper (Refereed)
    Abstract [en]

    Anaerobic co-digestion (AcoD) allows for underutilised digesters to increase biomethane production. The organic fraction of municipal solid waste (OFMSW), e.g. food waste, is an abundant substrate with high degradability and gas potential. This paper focuses on the implementation of codigestion of mixed sludge from wastewater treatment and OFMSW through batch and continuous labscale experiments, modelling and microbial population analysis. The results show a rapid adaptation of the process and an increase of the biomethane production of 20 to 40% with 50% OFMSW and it has an impact on the microbial community. The methanogenic activity increases and changes towards acetate degradation while the community without co-substrate remains unaffected. The modelling results show that ammonium inhibition increases at elevated organic loads and that intermittent feeding causes fluctuations in digester performance due to varying inhibition. Modelling can be successfully used for designing feed strategies and experimental set-ups for anaerobic co-digestion.

  • Edelbro, Catrin
    et al.
    Luleå University of Technology, Sweden .
    Hulthén, Erik
    Chalmers University of Technology, Sweden.
    Clausen, Elisabeth
    Technical University of Clausthal, Germany.
    Tanner, David
    University of Limerick, Ireland.
    Herrera Herbert, Juan
    Universidad Politécnica de Madrid, Spain.
    Jonsson, Kristina
    Luossavaara-Kiirunavaara AB (LKAB), Sweden.
    Bealieu, Stephan
    RUSAL Aughinish Alumina, Ireland.
    Kamp, Aldert
    Delft University of Technology, The Netherlands.
    Försth, Michael
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    European Initiative on CDIO in Raw Material Programmes2017Conference paper (Other academic)
    Abstract [en]

    One of five Knowledge and Innovation Communities (KICs), was launched in Europe in 2014 and has its focus on exploration, extraction, mineral processing, metallurgy, recycling and material substitution of raw materials. To reach the vision, where the European Union’s industrial strength is based on a cost-efficient, secure, sustainable supply and use of raw materials, a new generation of skilled people entering industry, universities and research needs to be developed. Today’s technical MSc graduates in raw materials and especially primary resources (i.e. exploration, extraction, mining and mineral processing and metallurgy) best suits large companies where they often act as specialists and experts. For small to medium enterprises as well as for our future engineers other skills than technical are necessary. As a part of the KIC Raw Materials, the education project “The implementation of CDIO in raw material programmes” started in 2016. The project focuses, during 2016-2017, on (WP1) faculty- and (WP2) pilot case development. There are no academic institutes in Europe that have yet applied CDIO for primary resource related MSc programmes. This paper describes an education project within the KIC Raw material and presents key outputs with implementing CDIO in mining and metallurgy related programmes.

  • Hoffmann, Lars
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Immersion of 400 volt traction battery in fresh water and salt water2018Report (Other academic)
    Abstract [en]

    By means of these tests, where Li-ion batteries have been immersed in both fresh water as well as 3 % salt water, it was demonstrated that it is completely safe to be both in the water and in the direct proximity of a battery, in this case, with 400 volt direct current. This conclusion holds, on the condition that the exposed individual, in the direct proximity of the battery, does not actively touch any of the battery's poles. Analogous to this, it can be assumed that nor does an electric vehicle, which for some reason has entered a watercourse consisting of either fresh water or seawater, constitute a danger for those bathing in the immediate vicinity of the electric vehicle. However, this assumes that an individual who is diving or bathing does not touch exposed parts of the traction system (explanation, e.g. open battery case and directly taking hold of live exposed parts of the traction battery and its cells). However, these parts are normally built into the vehicle's protective structures and are hard to access by inadvertent contact. The commercially available, factory produced, electric vehicles made by serious designers and automotive companies have a monitoring system in their systems that immediately switch off the power supply from the traction battery to the electric vehicle's traction system. This provides additional personal protection for anyone (e.g. fireman) who has the task of helping passengers who have entered a watercourse along with their electric vehicle. During immersion in salt water, a pungent chlorine gas was generated, which can be thought to collect inside a vehicle's air pockets; whether these gas mixtures are flammable or not has not been studied during these tests. No drastic events could be observed during any of these tests, however, one should be aware that a battery, which for some reason has been in immersed in water and has not discharged, can still have a hazardous voltage level after many months. This is something that the rescue service, automotive mechanics and car recyclers in particular should be informed.

  • Williams Portal, Natalie
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Flansbjer, MathiasRISE - Research Institutes of Sweden, Safety and Transport, Safety.Mueller, UrsRISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Analysis of the Flexural Behavior of Textile Reinforced Reactive Powder Concrete Sandwich Elements Using Optical Measurements2018Conference proceedings (editor) (Refereed)
    Abstract [en]

    Prefabricated and non-load bearing sandwich façade elements were developed using Textile Reinforced Reactive Powder Concrete (TRRPC) along with low density Foamed Concrete (FC) and Glass Fiber Reinforced Polymer (GFRP) continuous connecting devices. Four-point bending tests were performed on large-scale TRRPC sandwich element beams to characterize the structural performance, which included the flexural capacity, level of composite action, resulting deformation, crack propagation and failure mechanisms. Optical measurements based on Digital Image Correlation (DIC) were taken simultaneously to enable a detailed analysis of the underlying composite action. The structural behavior of the developed elements was found to be highly dependent on the stiffness and strength of the connectors to ensure composite action between the two TRRPC panels.

  • Höjer, Mattias
    et al.
    KTH Royal Institute of Technology, Sweden.
    Mjörnell, Kristina
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Measures and Steps for More Efficient Use of Buildings2018In: Sustainability, article id 1949Article in journal (Refereed)
    Abstract [en]

    As urbanization continues and more people move into cities and urban areas, pressure on availablelandfornewconstructionswillcontinuetoincrease. Thissituationconstitutesanincentiveto reviewtheneedforinteriorspaceandusesofexistingbuildings. Agreatdealcanbegainedfromusing existingbuildingsmoreefficientlyinsteadofconstructingnewones: Reducedresourceusageduring construction(investments,naturalresources,andenergy),operation,andmaintenance;moreactivityper squaremeterofbuildingscreatesagreaterbasisforpublictransportandotherservices;moreintensive useofbuildingscreatesamorevibrantcitywithoutbuildingonvirginland. Theaimofthispaperisto initiateadiscussionregardinghowdigitalizationcanaffectthedemandandsupplyofinteriorspace in existing buildings and elaborate on how policy can support more resource-efficient uses of space. New activity-based resource measurements intended for use in buildings are proposed, and several principles that have the potential to decrease environmental impact through more efficient usage of space are outlined. Based on these ideas for encouraging the flexible use of building spaces that are facilitatedbydigitalizationandthenewmeasurementapproaches,afour-stepprincipleforconstruction isproposed: Thefirststepistoreducethedemandforspace,thesecondistointensifyusageofexisting space, the third is to reconstruct and adapt existing buildings to current needs, and the fourth is to constructnewbuildings. Urgingpolitical,municipal,construction,andreal-estatedecisionmakersto contemplatethisprinciple,particularlyinviewofthenewconditionsthatdigitalizationentails,willlead tomoresustainableconstructionand,inthelongterm,asustainablebuiltenvironment.

  • Summerton, Emily
    et al.
    University of Birmingham, UK.
    Hollamby, Martin J
    University of Keele, UK.
    Zimbitas, Georgina
    University of Birmingham, UK.
    Snow, Tim
    Diamond Light Source, UK.
    Smith, Andrew J
    Diamond Light Source, UK.
    Sommertune, Jens
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    Bettiol, Jeanluc
    Procter and Gamble Brussels Innovation Center, Belgium.
    Jones, Christopher
    Procter and Gamble Brussels Innovation Center, Belgium.
    Britton, Melanie M
    University of Birmingham, UK.
    Bakalis, Serafim
    University of Birmingham, UK ; University of Nottingham, UK.
    The impact of N,N-dimethyldodecylamine N-oxide (DDAO) concentration on the crystallisation of sodium dodecyl sulfate (SDS) systems and the resulting changes to crystal structure, shape and the kinetics of crystal growth.2018In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 527, p. 260-266, article id S0021-9797(18)30579-4Article in journal (Refereed)
    Abstract [en]

    HYPOTHESIS: At low temperatures stability issues arise in commercial detergent products when surfactant crystallisation occurs, a process which is not currently well-understood. An understanding of the phase transition can be obtained using a simple binary SDS (sodium dodecyl sulfate) + DDAO (N,N-dimethyldodecylamine N-oxide) aqueous system. It expected that the crystallisation temperature of an SDS system can be lowered with addition of DDAO, thus providing a route to improve detergent stability.

    EXPERIMENTS: Detergent systems are typically comprised of anionic surfactants, non-ionic surfactants and water. This study explores the crystallisation of a three component system consisting of sodium dodecyl sulfate (SDS), N,N-dimethyldodecylamine N-oxide (DDAO), and water using wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC) and confocal Raman microscopy.

    FINDINGS: O, formed whereas for mixed SDS + DDAO systems no such structure was detected during crystallisation.

  • Chen, Zhi‑Qiang
    et al.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Lundén, Karl
    SLU Swedish University of Agricultural Sciences, Sweden.
    Karlsson, Bo
    Skogforsk, Sweden.
    Vos, Ingrid
    Skogforsk, Sweden.
    Olson, Åke
    SLU Swedish University of Agricultural Sciences, Sweden.
    Lundqvist, Sven-Olof
    RISE - Research Institutes of Sweden, Bioeconomy. IIC, Sweden.
    Stenlid, Jan
    SLU Swedish University of Agricultural Sciences, Sweden.
    Wu, Harry X.
    SLU Swedish University of Agricultural Sciences, Sweden ; CSIRO Plant Industry, Australia.
    García Gil, Maria Rosario
    SLU Swedish University of Agricultural Sciences, Sweden.
    Elfstrand, Malin
    SLU Swedish University of Agricultural Sciences, Sweden.
    Early selection for resistance to Heterobasidion parviporum in Norway spruce is not likely to adversely affect growth and wood quality traits in late-age performance2018In: European Journal of Forest Research, ISSN 1612-4669, E-ISSN 1612-4677Article in journal (Refereed)
    Abstract [en]

    Infections with Heterobasidion parviporum devalue the Norway spruce timber as the decayed wood does not meet the necessary quality requirements for sawing. To evaluate the incorporation of disease resistance in the Norway spruce breeding strategy, an inoculation experiment with H. parviporum on 2-year-old progenies of 466 open-pollinated families was conducted under greenhouse (nursery) conditions. Lesion length in the phloem (LL), fungal growth in sapwood (FG) and growth (D) were measured on an average of 10 seedlings for each family. The genetic variation and genetic correlations between both LL, FG and growth in the nursery trial and wood quality traits measured previously from 21-year old trees in two progeny trials, including solid-wood quality traits (wood density, and modulus of elasticity) and fiber properties traits (radial fiber width, tangential fiber width, fiber wall thickness, fiber coarseness, microfibril angle and fiber length). For both LL and FG, large coefficients of phenotypic variation (> 26%) and genetic variation (> 46%) were detected. Heritabilities of LL and FG were 0.33 and 0.42, respectively. We found no significant correlations between wood quality traits and growth in the field progeny trials with neither LL nor FG in the nursery trial. Our data suggest that the genetic gains may reach 41 and 52% from mass selection by LL and FG, respectively. Early selection for resistance to H. parviporum based on assessments of fungal spread in the sapwood in nursery material, FG, will not adversely affect growth and wood quality traits in late-age performance. 

  • Lindgren, J. Fredrik
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Ytreberg, Erik
    Chalmers university of Technology, Sweden.
    Holmqvist, Albin
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Dahlström, Magnus
    Chalmers university of Technology, Sweden.
    Dahl, Peter
    University of Gothenburg, Sweden.
    Berglin, Mattias
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Wrange, Anna-Lisa
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Dahlström, Mia
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Copper release rate needed to inhibit fouling on the west coast of Sweden and control of copper release using zinc oxide2018In: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454Article in journal (Refereed)
    Abstract [en]

    How zinc oxide influences copper release has been tested and the lowest release rate of copper from various combinations of copper and zinc in a paint matrix evaluated, whilst still deterring macrofouling, including barnacles and bryozoans. Copper (I) oxide was added to a generic AF paint in 0, 8.5, 11.7 or 16.3 wt% copper oxide in combination with 0, 10 or 20 wt% zinc oxide and applied on PMMA panels. The results show that zinc influences the release rate of copper. When 10 and 20 wt% zinc was added, the total amount of copper released significantly increased by on average 32 and 47% respectively. All treatments that included copper were successful in deterring macrofouling, including the treatment with the lowest average Cu release rate, ie 4.68 μg cm−2 day−1. 

  • Bouguelia, Mohamed-Rafik
    et al.
    Halmstad University, Sweden.
    Nowaczyk, Slawomir
    Halmstad University, Sweden.
    Payberah, Amir H.
    RISE - Research Institutes of Sweden, ICT, SICS.
    An adaptive algorithm for anomaly and novelty detection in evolving data streams2018In: Data mining and knowledge discovery, ISSN 1384-5810, E-ISSN 1573-756XArticle in journal (Refereed)
    Abstract [en]

    In the era of big data, considerable research focus is being put on designing efficient algorithms capable of learning and extracting high-level knowledge from ubiquitous data streams in an online fashion. While, most existing algorithms assume that data samples are drawn from a stationary distribution, several complex environments deal with data streams that are subject to change over time. Taking this aspect into consideration is an important step towards building truly aware and intelligent systems. In this paper, we propose GNG-A, an adaptive method for incremental unsupervised learning from evolving data streams experiencing various types of change. The proposed method maintains a continuously updated network (graph) of neurons by extending the Growing Neural Gas algorithm with three complementary mechanisms, allowing it to closely track both gradual and sudden changes in the data distribution. First, an adaptation mechanism handles local changes where the distribution is only non-stationary in some regions of the feature space. Second, an adaptive forgetting mechanism identifies and removes neurons that become irrelevant due to the evolving nature of the stream. Finally, a probabilistic evolution mechanism creates new neurons when there is a need to represent data in new regions of the feature space. The proposed method is demonstrated for anomaly and novelty detection in non-stationary environments. Results show that the method handles different data distributions and efficiently reacts to various types of change. 

  • Wedin, Helena
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Niit, Ellinor
    Swedish School of Textiles, Sweden.
    Mansoor, Z. Ahmad
    re:newcell AB, Sweden.
    Kristinsdottir, Anna Runa
    Swerea IVF, Sweden.
    de la Motte, Hanna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Jönsson, Christina
    Swerea IVF, Sweden.
    Östlund, Åsa
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Lindgren, Christofer
    re:newcell AB, Sweden.
    Preparation of Viscose Fibres Stripped of Reactive Dyes and Wrinkle-Free Crosslinked Cotton Textile Finish2018In: Journal of polymers and the environment, ISSN 1566-2543, E-ISSN 1572-8919Article in journal (Refereed)
    Abstract [en]

    The chemical recycling of cellulosic fibres may represent a next-generation fibre–fibre recycling system for cotton textiles, though remaining challenges include how to accommodate fibre blends, dyes, wrinkle-free finishes, and other impurities from finishing. These challenges may disrupt the regeneration process steps and reduce the fibre quality. This study examines the impact on regenerated viscose fibre properties of a novel alkaline/acid bleaching sequence to strip reactive dyes and dimethyloldihydroxyethyleneureas (DMDHEU) wrinkle-free finish from cotton textiles. Potentially, such a bleaching sequence could advantageously be integrated into the viscose process, reducing the costs and environmental impact of the product. The study investigates the spinning performance and mechanical properties (e.g., tenacity and elongation) of the regenerated viscose fibres. The alkaline/acid bleaching sequence was found to strip the reactive dye and DMDHEU wrinkle-free finish from the cotton fabric, so the resulting pulp could successfully be spun into viscose fibres, though the mechanical properties of these fibres were worse than those of commercial viscose fibres. This study finds that reactive dyes and DMDHEU wrinkle-free finish affect the viscose dope quality and the regeneration performance. The results might lead to progress in overcoming quality challenges in cellulosic chemical recycling. 

  • Lo Re, Giada
    et al.
    KTH Royal Institute of Technology, Sweden.
    Spinella, Stephen
    NYU Tandon School of Engineering, US.
    Boujemaoui, Assya
    KTH Royal Institute of Technology, Sweden.
    Vilaseca, Fabiola
    University of Girona, Italy.
    Larsson, Per Tomas
    KTH Royal Institute of Technology, Sweden.
    Adås, Fredrik
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Berglund, Lars A.
    KTH Royal Institute of Technology, Sweden.
    Poly(ϵ-caprolactone) Biocomposites Based on Acetylated Cellulose Fibers and Wet Compounding for Improved Mechanical Performance2018In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 6, no 5, p. 6753-6760Article in journal (Refereed)
    Abstract [en]

    Poly(ϵ-caprolactone) (PCL) is a ductile thermoplastic, which is biodegradable in the marine environment. Limitations include low strength, petroleum-based origin, and comparably high cost. Cellulose fiber reinforcement is therefore of interest although uniform fiber dispersion is a challenge. In this study, a one-step wet compounding is proposed to validate a sustainable and feasible method to improve the dispersion of the cellulose fibers in hydrophobic polymer matrix as PCL, which showed to be insensitive to the presence of the water during the processing. A comparison between unmodified and acetylated cellulosic wood fibers is made to further assess the net effect of the wet feeding and chemical modification on the biocomposites properties, and the influence of acetylation on fiber structure is reported (ATR-FTIR, XRD). Effects of processing on nanofibrillation, shortening, and dispersion of the cellulose fibers are assessed as well as on PCL molar mass. Mechanical testing, dynamic mechanical thermal analysis, FE-SEM, and X-ray tomography is used to characterize composites. With the addition of 20 wt % cellulosic fibers, the Young's modulus increased from 240 MPa (neat PCL) to 1850 MPa for the biocomposites produced by using the wet feeding strategy, compared to 690 MPa showed for the biocomposites produced using dry feeling. A wet feeding of acetylated cellulosic fibers allowed even a greater increase, with an additional 46% and 248% increase of the ultimate strength and Young's modulus, when compared to wet feeding of the unmodified pulp, respectively. 

  • A. Hosseini, Vahid
    et al.
    University West, Sweden ; Innovatum AB, Sweden.
    Karlsson, Leif
    University West, Sweden.
    Örnek, Cem
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB. KTH Royal Institute of Technology, Sweden.
    Reccagni, Pierfrance
    The University of Manchester, UK.
    Wessman, Sten
    University West, Sweden.
    Engelberg, Dirk
    The University of Manchester, UK.
    Microstructure and functionality of a uniquely graded super duplex stainless steel designed by a novel arc heat treatment method2018In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 139, p. 390-400Article in journal (Refereed)
    Abstract [en]

    A novel arc heat treatment technique was applied to design a uniquely graded super duplex stainless steel (SDSS), by subjecting a single sample to a steady state temperature gradient for 10 h. A new experimental approach was used to map precipitation in microstructure, covering aging temperatures of up to 1430 °C. The microstructure was characterized and functionality was evaluated via hardness mapping. Nitrogen depletion adjacent to the fusion boundary depressed the upper temperature limit for austenite formation and influenced the phase balance above 980 °C. Austenite/ferrite boundaries deviating from Kurdjumov–Sachs orientation relationship (OR) were preferred locations for precipitation of σ at 630–1000 °C, χ at 560–1000 °C, Cr2N at 600–900 °C and R between 550 °C and 700 °C. Precipitate morphology changed with decreasing temperature; from blocky to coral-shaped for σ, from discrete blocky to elongated particles for χ, and from polygonal to disc-shaped for R. Thermodynamic calculations of phase equilibria largely agreed with observations above 750 °C when considering nitrogen loss. Formation of intermetallic phases and 475 °C-embrittlement resulted in increased hardness. A schematic diagram, correlating information about phase contents, morphologies and hardness, as a function of exposure temperature, is introduced for evaluation of functionality of microstructures. 

  • Silander, Isak
    et al.
    Umeå University, Sweden.
    Hausmaninger, Thomas
    Umeå University, Sweden.
    Zelan, Martin
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Axner, Ove
    Umeå University, Sweden.
    Gas modulation refractometry for high-precision assessment of pressure under nonerature-stabilized conditions2018In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 36, no 3, article id 03E105Article in journal (Refereed)
    Abstract [en]

    The authors report on the realization of a novel methodology for refractometry - GAs modulation refractometry (GAMOR) - that decreases the influence of drifts in Fabry Perot cavity refractometry. The instrumentation is based on a dual Fabry-Perot cavity refractometer in which the beat frequency between the light fields locked to two different cavities, one measurement and one reference cavity, is measured. The GAMOR methodology comprises a process in which the measurement cavity sequentially is filled and evacuated while the reference cavity is constantly evacuated. By performing beat frequency measurements both before and after the finite-pressure measurement, zero point references are periodically created. This opens up for high precision refractometry under nontemperature-stabilized conditions. A first version of an instrumentation based on the GAMOR methodology has been realized and its basic performance has been scrutinized. The refractometer consists of a Zerodur cavity-block and tunable narrow linewidth fiber lasers operating within the C34 communication channel (i.e., around 1.55 μm) at which there are a multitude of fiber coupled off-the-shelf optical, electro-optic, and acousto-optic components. The system is fully computer controlled, which implies it can perform unattended gas assessments over any foreseeable length of time. When applied to a system with no active temperature stabilization, the GAMOR methodology has demonstrated a 3 orders of magnitude improvement of the precision with respect to conventional static detection. When referenced to a dead weight pressure scale the instrumentation has demonstrated assessment of pressures in the kilo-Pascal range (4303 and 7226 Pa) limited by white noise with standard deviations in the 3.2 N - 1 / 2 - 3.5 N - 1 / 2 mPa range, where N is the number of measurement cycles (each being 100 s long). For short measurement times (up to around 103 s), the system exhibits a (1 σ) total relative precision of 0.7 (0.5) ppm for assessment of pressures in the 4 kPa region and 0.5 (0.4) ppm for pressures around 7 kPa, where the numbers in parentheses represent the part of the total noise that has been attributed to the refractometer. As long as the measurement procedure is performed over short time scales, the inherent properties of the GAMOR methodology allow for high precision assessments by the use of instrumentation that is not actively temperature stabilized or systems that are affected by outgassing or leaks. They also open up for a variety of applications within metrology; e.g., transfer of calibration and characterization of pressure gauges, including piston gauges. 

  • Steinert, Rebecca
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Zarifeh, Nidal
    Univ. Duisburg-Essen, Germany.
    Chang, Chia-Yu
    EURECOM, France.
    Anttonen, Antti
    VTT, Finland.
    Cipriano, Antonio
    Thales, France.
    Panaitopol, Dorin
    Thales, France.
    Toward Unifying Abstractions for Heterogeneous Radio Infrastructures2017In: Proceedings of EuCNC 2017, 2017Conference paper (Refereed)
    Abstract [en]

    The development toward programmatic operation and control of 5G networks is a compelling and technically challenging task. A fundamental component is the capability of exposing and controlling the network state across heterogeneous equipment in a unified manner. In this paper, we outline the COHERENT approach to network abstractions enabling unified representation and programming of heterogeneous radio access networks.

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