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  • 51.
    Berggren, Kristina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Toxicity of chlorantraniliprole to the Collembola Folsomia candida: toxicodynamics and effects of organic matter content2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Toxicity of pesticides to non-target organisms determines their impact on natural environments. And to find pesticides with a new, target-specific mode of action, which are safe to farmers and organisms in the surrounding environment, is important when developing new pesticides.In this study, toxicity of the insecticide chlorantraniliprole to the Collembola Folsomia candida was investigated, showing that the test animals were adversely affected by the compound. Toxicity was tested in two experiments; a reproduction test in four soils with different organic matter content, following the OECD Guideline 232, and a toxicodynamic test where mortality, mobility, reproduction and morphological changes were recorded.The reproduction test showed a lower toxicity of chlorantraniliprole in the high-organic soils compared to the low-organic. When organic matter content increased two times, the difference between the lowest and the highest EC50 and EC10 values was a factor of 5.3 and 8.4, respectively. pH did not seem to significantly affect toxicity, and organic matter content did not seem to affect the total number of juveniles produced.The toxicodynamic test showed a fast mode of action on mobility of F. candida, but not on mortality. Mobility decreased at the highest treatments of chlorantraniliprole already one day after the animals were introduced to the test vessels, but significant mortality was still not seen after almost three weeks. Reproduction was also adversely affected with a decline in the total number of juveniles produced at the higher treatments. The animals at the higher treatments also showed a possible compound induced reproduction stress, with faster egg laying. Morphological changes, such as affected antennas, increased steadily over time.Chlorantraniliprole shows high toxicity to some non-target organisms but is, with its new mode of action, still important in the development of more environmentally safe pesticides.

  • 52.
    Bernes, C.
    et al.
    Mistra Council for Evidence-Based Environmental Management, Royal Swedish Academy of Sciences, Stockholm, Sweden .
    Jonsson, Bengt-Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Junninen, K.
    Metsähallitus Parks and Wildlife Finland, C/o UEF, P.O. Box 111, Joensuu, Finland .
    Lõhmus, A.
    Institute of Ecology and Earth Sciences, Tartu University, Vanemuise 46, Tartu, Estonia .
    Macdonald, E.
    Department of Renewable Resources, University of Alberta, 751 General Services Building, Edmonton, AB, Canada .
    Müller, J.
    Department of Conservation and Research, Bavarian Forest National Park, Freyunger Str. 2, Grafenau, Germany .
    Sandström, Jennie
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    What is the impact of active management on biodiversity in boreal and temperate forests set aside for conservation or restoration?: A systematic map2015In: Environmental Evidence, ISSN 2047-2382, E-ISSN 2047-2382, Vol. 4, no 1, article id 25Article in journal (Refereed)
    Abstract [en]

    Background: The biodiversity of forests set aside from forestry is often considered best preserved by non-intervention. In many protected forests, however, remaining biodiversity values are legacies of past disturbances, e.g. recurring fires, grazing or small-scale felling. These forests may need active management to keep the characteristics that were the reason for setting them aside. Such management can be particularly relevant where lost ecological values need to be restored. In this review, we identified studies on a variety of interventions that could be useful for conserving or restoring any aspect of forest biodiversity in boreal and temperate regions. Since the review is based on Swedish initiatives, we have focused on forest types that are represented in Sweden, but such forests exist in many parts of the world. The wide scope of the review means that the set of studies is quite heterogeneous. As a first step towards a more complete synthesis, therefore, we have compiled a systematic map. Such a map gives an overview of the evidence base by providing a database with descriptions of relevant studies, but it does not synthesise reported results. Methods: Searches for literature were made using online publication databases, search engines, specialist websites and literature reviews. Search terms were developed in English, Finnish, French, German, Russian and Swedish. We searched not only for studies of interventions in actual forest set-asides, but also for appropriate evidence from commercially managed forests, since some practices applied there may be useful for conservation or restoration purposes too. Identified articles were screened for relevance using criteria set out in an a priori protocol. Descriptions of included studies are available in an Excel file, and also in an interactive GIS application that can be accessed at an external website. Results: Our searches identified nearly 17,000 articles. The 798 articles that remained after screening for relevance described 812 individual studies. Almost two-thirds of the included studies were conducted in North America, whereas most of the rest were performed in Europe. Of the European studies, 58 % were conducted in Finland or Sweden. The interventions most commonly studied were partial harvesting, prescribed burning, thinning, and grazing or exclusion from grazing. The outcomes most frequently reported were effects of interventions on trees, other vascular plants, dead wood, vertical stand structure and birds. Outcome metrics included e.g. abundance, richness of species (or genera), diversity indices, and community composition based on ordinations. Conclusions: This systematic map identifies a wealth of evidence on the impact of active management practices that could be utilised to conserve or restore biodiversity in forest set-asides. As such it should be of value to e.g. conservation managers, researchers and policymakers. Moreover, since the map also highlights important knowledge gaps, it could inspire new primary research on topics that have so far not been well covered. Finally, it provides a foundation for systematic reviews on specific subtopics. Based on our map of the evidence, we identified four subtopics that are sufficiently covered by existing studies to allow full systematic reviewing, potentially including meta-analysis. © 2015 Bernes et al.

  • 53.
    Bernes, Claes
    et al.
    Royal Swedish Academy of Sciences, Stockholm, Sweden .
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Junninen, Kaisa
    Metsähallitus Parks & Wildlife Finland.
    Asko, Lõhmus
    Tartu University, Estonia.
    McDonald, Ellen
    University of Alberta, Canada.
    Müller, Jörg
    Department of Conservation and Research, Bavarian Forest National Park, Germany.
    Sandström, Jennie
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    What is the impact of active management on biodiversity in forests set aside for conservation or restoration?: A systematic review protocol2014In: Environmental Evidence, ISSN 2047-2382, E-ISSN 2047-2382, Vol. 3, no 22Article in journal (Refereed)
    Abstract [en]

    Background

    The traditional approach to limiting impacts of forestry on biodiversity is to set aside forest areas of particular conservation interest, either as formally protected reserves or on a voluntary basis. Many set-asides are left more or less untouched, but some of them have a history of disturbances such as wildfires, forest grazing, coppicing or small-scale felling. Such areas may gradually lose the qualities that were to be safeguarded unless the disturbances are re-introduced (e.g. by burning) or replaced with alternatives (e.g. gap-felling). Active management of forest set-asides may be particularly relevant in areas where the biota has been impoverished by intensive and large-scale harvesting. Here, biodiversity may not be able to recover adequately without restoration measures such as gap-felling or creation of dead wood.

    In recent years, interest in active management of forest set-asides has increased, but opinions differ among conservationists on how such management should be balanced against non-intervention. The topic of the proposed systematic review has therefore met approval among stakeholders in Sweden, where it is currently an issue of high concern.

    Methods

    The review will examine primary field studies of how various forms of active management have affected biodiversity in boreal or temperate forests set aside for conservation or restoration. The primary focus will be on forest types represented in Sweden. In some cases, useful insights about management options may also be provided by studies of interventions in commercially managed forests. Non-intervention or alternative forms of active management will be used as comparators. Relevant outcomes include assemblage diversity (species richness, diversity indices), abundance of different functional or taxonomic groups of organisms, population viability of target species, and indicators of forest biodiversity such as forest structure and amounts of dead wood.

    The relevant scientific literature may turn out to be very heterogeneous, however. Numerous combinations of management forms and biodiversity outcomes can be conceived, and it remains to be seen whether any such combination is covered by sufficiently many studies to allow a meaningful meta-analysis. Nonetheless, it should be feasible to achieve a useful narrative synthesis of the available evidence.

  • 54.
    Bernes, Claes
    et al.
    Mistra Council for Evidence-Based Environmental Management, Stockholm Environment Institute, Stockholm.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Junninen, Kaisa
    Metsähallitus Parks and Wildlife Finland, Joensuu, Finland; School of Forest Sciences, University of Eastern Finland, Joensuu, Finland .
    Lõhmus, Asko
    Institute of Ecology and Earth Sciences, Tartu University, Vanemuise 46, Tartu, Estonia.
    Macdonald, Ellen
    Department of Renewable Resources, University of Alberta, 751 General Services Building, Edmonton, AB, Canada.
    Müller, Jörg
    Department of Conservation and Research, Bavarian Forest National Park, Freyunger Str. 2, Grafenau, Germany.
    Sandström, Jennie
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    What are the impacts of manipulating grazing and browsing by ungulates on plants and invertebrates in temperate and boreal forests?: A systematic review protocol2016In: Environmental Evidence, ISSN 2047-2382, E-ISSN 2047-2382, Vol. 5, no 1, article id 17Article in journal (Refereed)
    Abstract [en]

    Background: Livestock grazing and 'overabundance' of large wild herbivores in forested areas have long been perceived as conflicting with the aims of both silviculture and forest conservation; however, certain kinds of herbivory can help to maintain habitat values in forest ecosystems. Management of grazing/browsing in protected forests can, therefore, be a critical tool for biodiversity conservation. However, it is not clear what impacts of wild ungulates or livestock are tolerable or desirable in forests set aside for conservation or restoration. The primary aim of the proposed systematic review is to clarify how the diversity of plants and invertebrates is affected by manipulation of the grazing/browsing pressure by livestock or wild ungulates. The ultimate purpose of the review is to investigate whether such manipulation is useful as a means of conserving or restoring biodiversity in forest set-asides. Methods: The review will examine primary field studies of how fencing or other kinds of manipulation of the grazing/browsing pressure by livestock or wild ungulates affects plants or invertebrates. We will consider studies made in boreal or temperate forests anywhere in the world, incorporating investigations made not only in protected areas but also in stands under commercial management. Non-intervention or alternative levels of grazing pressure will be used as comparators. Relevant outcomes include abundance, diversity and composition of plants and invertebrates, tree regeneration, and performance of focal/target species. Relevant studies will mainly be selected from a recent systematic map of the evidence on biodiversity impacts of active management in forest set-asides. A search update will be made with a subset of the search terms used for the systematic map. Searches for additional literature will be made in bibliographies of existing reviews. Relevant studies will be subject to critical appraisal and categorised as having high, medium or low susceptibility to bias. Studies with high susceptibility to bias will be excluded from the review. Useful outcomes and data on interventions and other potential effect modifiers will be extracted from included articles. A narrative synthesis will describe the quality and findings of all studies in the review. Where studies report similar outcomes, meta-analysis will be performed.

  • 55.
    Bernes, Claes
    et al.
    Stockholm Environment Institute.
    Macura, Biljana
    Stockholm Environment Institute.
    Jonsson, Bengt-Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Junninen, Kaisa
    Metsähallitus Parks and Wildlife Finland, Joensuu, Finland; University of Eastern Finland, Joensuu, Finland.
    Müller, Jörg
    Dept. of Conservation and Research, Bavarian Forest National Park, Grafenau, Germany.
    Sandström, Jennie
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lõhmus, Asko
    Tartu University, Tartu, Estonia.
    Macdonald, Ellen
    University of Alberta, Edmonton, AB, Canada.
    Manipulating ungulate herbivory in temperate and boreal forests: Effects on vegetation and invertebrates. A systematic review2018In: Environmental Evidence, ISSN 2047-2382, E-ISSN 2047-2382, Vol. 7, no 1, article id 13Article, review/survey (Refereed)
    Abstract [en]

    Background: Livestock grazing and 'overabundance' of large wild herbivores in forested areas have long been perceived as conflicting with the aims of both silviculture and forest conservation; however, certain kinds of herbivory can help to maintain habitat values in forest ecosystems. Management of mammalian herbivory in protected forests can, therefore, be a critical tool for biodiversity conservation. The primary aim of this systematic review was to examine how forest vegetation and invertebrates are affected by manipulation of the grazing/browsing pressure by livestock or wild ungulates. The ultimate purpose was to investigate whether such manipulation is useful for conserving or restoring biodiversity in forest set-asides. Methods: We considered studies of manipulated ungulate herbivory in forests anywhere within the boreal and temperate zones, not only in protected areas but also in production forest. Non-intervention or alternative levels of intervention were used as comparators. Relevant outcomes included abundance, diversity and composition of plants and invertebrates, tree regeneration, and performance of focal/target species. Studies were mainly selected from a recent systematic map of the evidence on biodiversity effects of forest management relevant to protected areas. Additional studies were identified through updated searches online and in bibliographies of existing reviews. Relevant studies were critically appraised, and studies with low or unclear validity were excluded from the review. Quantitative outcomes were extracted from 103 articles, and summary effect sizes were derived by meta-analysis. Results: Most of the 144 studies included in the review had been conducted in North America, Europe or Australia/New Zealand. The intervention most commonly studied was experimental exclusion (or enclosure) of wild and/or domestic ungulates by fencing. Other studies examined culling of wild ungulates or compared forests long grazed by livestock to ungrazed forests. Effects on vegetation and invertebrates were reported in 135 and 23 of the studies, respectively. We found negative responses to herbivory in the abundance of understorey vegetation as a whole, woody understorey and bryophytes, and also in the species richness of woody understorey vegetation, whereas the richness of forbs and bryophytes responded positively. Several effects depended on ungulate origins: Understorey abundance responded negatively to livestock and to ungulates introduced into the wild, but not to native ones. In contrast, understorey species richness responded positively to livestock but not to wild ungulates. The duration and intensity of herbivory had few significant effects on vegetation - exceptions included woody understorey abundance and richness, which decreased with increasing duration and intensity, respectively. Among invertebrates we found negative responses to herbivory in the abundance of lepidopterans and spiders, but no significant effects on species richness. Conclusions: Our review revealed a large body of high-validity experimental studies on impacts of ungulate herbivory in forests. This evidence confirmed that manipulation of such herbivory is often highly influential on tree regeneration and on the abundance, diversity and composition of understorey vegetation. Nevertheless, we also identified important knowledge gaps - we found few studies of boreal areas, long-term herbivory effects, impacts on bryophytes, lichens and invertebrates, and effects of manipulation less radical than total exclusion of ungulates. 

  • 56.
    Blomquist, Nicklas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Large-Scale Nanographite Exfoliation for Low-Cost Metal-Free Supercapacitors2016Licentiate thesis, comprehensive summary (Other academic)
  • 57.
    Blomquist, Nicklas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Paper based Supercapacitors for vehicle KERS-application2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    High mobility has been a standard in the modern world for decades. This has resulted in high energy consumption, diminishing fossil energy reserves and rising levels of greenhouse gases.

    By recovering the energy lost in deceleration of vehicles the total energy consumption can be decreased and exhaust emissions reduced. This can be done with a kinetic energy recovery system (KERS) that converts kinetic energy to electric energy during deceleration, which then can be used for acceleration.

    KERS requires an electrical storage device with high power density, due to the high power levels generated at heavy braking. Batteries does not generally meet these requirements, especially in the cost-effective point of view, but different types of capacitors can be used to obtain a cheap and effective system. To get such an energy storage device small, lightweight and inexpensive while the technology is sustainable requires avoidance of rare metals and hazardous materials.

    In this master thesis energy and power levels for KERS has been modelled, based on standardized measurements techniques and small paper-based supercapacitors have been built and tested in order to model size, weight and price for a full-scale energy storage device to a KERS-application.

    The models showed that energy consumption in urban traffic could be reduced with 18% and with an electrode material for the energy storage device with a capacitance of about 1500 F/m2 a reasonable size and weight is obtained. To reach these values of capacitance in paper-based supercapacitors further testing is required on area and layer dependence and for different electrodes.

  • 58.
    Blomquist, Nicklas
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Engström, Ann-Christine
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hummelgård, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Large-Scale Production of Nanographite by Tube-Shear Exfoliation in Water2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 4, article id e0154686Article in journal (Refereed)
    Abstract [en]

    The number of applications based on graphene, few-layer graphene, and nanographite is rapidly increasing. A large-scale process for production of these materials is critically needed to achieve cost-effective commercial products. Here, we present a novel process to mechanically exfoliate industrial quantities of nanographite from graphite in an aqueous environment with low energy consumption and at controlled shear conditions. This process, based on hydrodynamic tube shearing, produced nanometer-thick and micrometer-wide flakes of nanographite with a production rate exceeding 500 gh-1 with an energy consumption about 10 Whg-1. In addition, to facilitate large-area coating, we show that the nanographite can be mixed with nanofibrillated cellulose in the process to form highly conductive, robust and environmentally friendly composites. This composite has a sheet resistance below 1.75 Ω/sq and an electrical resistivity of 1.39×10-4 Ωm and may find use in several applications, from supercapacitors and batteries to printed electronics and solar cells. A batch of 100 liter was processed in less than 4 hours. The design of the process allow scaling to even larger volumes and the low energy consumption indicates a low-cost process.

  • 59.
    Blomquist, Nicklas
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. STT Emtec AB, Sundsvall.
    Wells, Thomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Bäckström, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Metal-free supercapacitor with aqueous electrolyte and low-cost carbon materials2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 39836Article in journal (Refereed)
    Abstract [en]

    Electric double-layer capacitors (EDLCs) or supercapacitors (SCs) are fast energy storage devices with high pulse efficiency and superior cyclability, which makes them useful in various applications including electronics, vehicles and grids. Aqueous SCs are considered to be more environmentally friendly than those based on organic electrolytes. Because of the corrosive nature of the aqueous environment, however, expensive electrochemically stable materials are needed for the current collectors and electrodes in aqueous SCs. This results in high costs for a given energy-storage capacity. To address this, we developed a novel low-cost aqueous SC using graphite foil as the current collector and a mix of graphene, nanographite, simple water-purification carbons and nanocellulose as electrodes. The electrodes were coated directly onto the graphite foil by using casting frames and the SCs were assembled in a pouch cell design. With this approach, we achieved a material cost reduction of greater than 90% while maintaining approximately one-half of the specific capacitance of a commercial unit, thus demonstrating that the proposed SC can be an environmentally friendly, low-cost alternative to conventional SCs.

  • 60.
    Boija, Susanne
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Almesåker, Ann
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Bylund, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Determination of conditional stability constants for some divalent transition metal ion-EDTA complexes by electrospray ionization mass spectrometry2014In: Journal of Mass Spectrometry, ISSN 1076-5174, E-ISSN 1096-9888, Vol. 49, no 7, p. 550-556Article in journal (Refereed)
    Abstract [en]

    Conditional stability constants of coordination complexes comprising divalent transition metals, Cu2+, Ni2+, Zn2+, Co2+, and ethylenediaminetetraacetic acid (EDTA) were determined utilizing electrospray ionization mass spectrometry. The deviation of signal response of a reference complex was monitored at addition of a second metal ion. The conditional stability constant for the competing metal was then determined through solution equilibria equations. The method showed to be applicable to a system where Co2+ and Zn2+ competed for EDTA at pH 5. When Cu2+ and Ni2+ competed for EDTA, the equilibrium changed over time. This change was shown to be affected in rate and size by the type of organic solvent added. In this work, 30% of either methanol or acetonitrile was used. It was found that if calibration curves are prepared for both metal complexes in solution and the measurements are repeated with sufficient time space, any change in equilibrium of sample solutions will be discovered. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

  • 61.
    Bylund, Dan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Henriksson, Anders E.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Sundsvalls sjukhus.
    Proteomic approaches to identify circulating biomarkers in patients with abdominal aortic aneurysm2015In: American Journal of Cardiovascular Disease, ISSN 2160-200X, Vol. 5, no 3, p. 140-145Article, review/survey (Refereed)
    Abstract [en]

    Abdominal aortic aneurysm (AAA) is a common condition with high mortality when ruptured. Most clinicians agree that small AAAs are best managed by ultrasonographic surveillance. However, it has been stated in recent reviews that a serum/plasma biomarker that predicts AAA rupture risk would be a powerful tool in stratifying patients with small AAAs. Identification of such circulating biomarkers with traditional hypothesis driven studies has been unsuccessful. In this review we summarize six studies using different proteomic approaches to find new, potential plasma AAA biomarker candidates. In conclusion, by using proteomic approaches novel potential plasma biomarkers for AAA have been identified.

  • 62.
    Bäverståhl, Araya
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Val av provmetod för mätning avslitage: Slitage på en flisledare2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    inom sågverksindustrin.Syftet med arbetet har varit att hitta en provmetod för mätning av abrasivnötning på en flisledare, åt företaget Andritz Iggesund Tools som vill minskaslitaget på sina flisledare. Flisledarna påverkats av en typ avslitage som kallasför abrasiv nötning. Det som har utförts under arbetet är litteraturstudieravseende olika nötningsmekanismer samt både visuella ochmikroskopistudier för att se hur slitage påverkar en flisledares ytor.Av de fem olika provmetoder som presenteras i rapporten, så valdes enprovmetod ut. Provmetoden som valdes kommer inte att studeras i praktikeneftersom det saknas resurser för att kunna utföra en serie prov.Den valda metoden, gummihjulsmetoden, är tillämpbar vad avser tre -­‐‑kroppars abrasiv nötning och anses vara bäst lämpad för de förhållanden somgäller för flisledaren. Provutrustning för gummihjulsmetoden är tillgänglig påmarknaden och prisuppgifter och kontaktuppgifter ges i rapporten.

  • 63.
    Cao, Weilan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Level and structure of SNP and indel variation between individuals on large (North America and Sweden) and small (within Sweden) geographic scale of Phlebiopsis gigantea2014Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
  • 64.
    Carlberg, Torbjorn
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Jarfors, Anders E. W.
    School of Engineering, Jönköping University, 55111 Jönköping, Sweden .
    On Vertical Drag Defects Formation During Direct Chill (DC) Casting of Aluminum Billets2014In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 45, no 1, p. 175-181Article in journal (Refereed)
    Abstract [en]

    During air-slip direct chill casting of aluminum billets, one of the major defects occurring includes traces along the billet called vertical drags (VDs). If the VDs are too deep or too many, then they cause scraping of the billets. As in the subsequent extrusion process, the surface quality is known to impair both the productivity and quality of the profiles. In cast-house practice, many theories circulate about the causes of VD defects and how to avoid them, but in the literature, no thorough treatments have been made to explain this phenomenon. In the current study, the outer appearance, structure around, and compositions at the defects are analyzed. A theory for the formation of the defects, their cause, and how their appearance is coupled to different alloy types is presented. The segregation in the vicinity of the defects is discussed based on deformation of semisolid materials and coupled to Reynolds dilatancy in granular materials. The theory can explain differences between 6063 and 6005 alloys.

  • 65.
    Carlberg, Torbjörn
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Bayat, Nazlin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Erdegren, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Surface Segregation and Surface Defect Formation During Aluminum Billet Casting2015In: Transactions of the Indian Institute of Metals, ISSN 0972-2815, E-ISSN 0975-1645, Vol. 68, no 6, p. 1065-1069Article in journal (Refereed)
    Abstract [en]

    In this paper the surface zone formation during direct chill casting of aluminum billets, produced by the air slip technology, is discussed. The shell zone depth and compositions have been quantitatively studied, and the surface microstructures of 6060, 6005 and 6082 alloys are compared and coupled to surface appearances. The understanding of the results is based on the exudation of liquid metal through the mushy zone and the fact that the exudate liquid is contained within a surface oxide skin, and the oxide skin movements are coupled to various surface appearances. The major defects that occur during billet castings are different kinds of vertical drags or horizontal bandings, also called lapping. The structures coupled to these defects and theories for their formation are discussed.

  • 66.
    Carlsson, Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Short communication: fruiting body production in two species of wood-decaying Basidiomycetes induced by pre-inoculation2016In: Mycological progress, ISSN 1617-416X, E-ISSN 1861-8952, Vol. 15, no 2, article id 16Article in journal (Refereed)
    Abstract [en]

    This study evaluated pre-inoculation to induce fruiting body production in wood-decaying fungi, using two species that readily create basidiomata in the laboratory: Antrodia sinuosa and Junghuhnia luteoalba. A new method was implemented in which the substrate was modified by species-specific pre-inoculation. We found that the use of the pre-inoculated substrate reduced the length of time necessary for the production of fruiting bodies. Under these conditions, both species produced basidiomata in 1-2 weeks, whereas over 2 months was required on a non-modified substrate. Thus we conclude that the induction of fruiting body production by pre-inoculation is possible, and we discuss the effect of the substrate modification.

  • 67.
    Carlsson, Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Wood Fungi and Forest Fire2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [sv]

    Forest fires have been the major stand-replacing/modifying disturbance in boreal forests. To adapt to fire disturbance, different strategies have evolved. This thesis focuses on wood fungi, and the effect of forest fire on this organism group. In many ways it is a study on adaptation to forest fire, in concurrence with adaptation to dry open habitats. In Paper I we study increased heat resistance in  mycelia from species prevalent in fire prone environments. Fungi were cultivated on fresh wood and exposed to different temperatures. Species prevalent in fire affected habitats had a much higher survival rate over all combinations of time and temperature compared to species associated with other environments. Based on this results the competitiveness was tested after temperature stress (paper II), three fire associated species, were tested against three non fire associated species. All fire associated species had a clear advantage after heat treatment, conquering a larger volume of wood than its competitor. In paper III we studied the effect of heat shock on decomposition rate, 18 species was tested. Species were cultivated and monitored for CO2 accumulation for 8 weeks and then heat shocked. All species including non fire associated species seemed to up-regulate decomposition after heat shock, this response was more pronounced in fire associated species. To look at the possible effect of forest fire on population structure (Paper IV), we developed 29 SNP/INDELs for Phlebiopsis. gigantea. We amplified the marker containing fragments in 132 individuals of P. gigantea in 6 populations, 3 which were found in areas affected by forest fire and 3 in unaffected areas. We found no genetic structure in accordance to forest fire. However we detected geographic structure, which stands in contrast to earlier studies. This might be due to the method, using SNP´s and number of individuals in the study. Finally we collected cross-sections of decayed logs to evaluate the number of fungal species domains that are likely to be hit when drilling a saw-dust sample in a log. We used these estimates to simulate how many species that will be found by a certain number of samples. We found that in 99% of the

  • 68.
    Carlsson, Fredrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edman, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Holm, Svante
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Effect of heat on interspecific competition in saprotrophic wood fungi2014In: Fungal ecology, ISSN 1754-5048, E-ISSN 1878-0083, Vol. 11, p. 100-106Article in journal (Refereed)
    Abstract [en]

    Some boreal wood fungi that are associated with forest fire or open dry habitats have an increased resistance to heat in comparison to species associated with a less specific distribution or species found in mesic forests. We hypothesize that extreme temperature-stress experienced during fires will favor species adapted to heat and, ultimately, the composition of species inhabiting logs in such habitats will change. Competitiveness after temperature stress was examined in three fire-associated species – Dichomitus squalens, Gloeophyllum sepiarium and Phlebiopsis gigantea – and three non fire-associated species – Ischnoderma benzoinum, Phellinus pini and Fomitopsis pinicola. There was a difference between the fire-associated species and the non fire-associated species with respect to competitive strength after heat stress. All fire-associated species had an advantage after heat treatment, colonizing a larger volume of wood than any non-fire-associated competitor. Our findings suggest that increased heat tolerance of mycelia can exert a competitive balance shift after forest fire. It shows that a system governed by forest fire will be dominance controlled under certain conditions. Furthermore, from a management perspective, during a prescribed burning, certain species already present in the ecosystem will be favored if the fire is not allowed to totally consume the substrates.

  • 69.
    Carlsson, Fredrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edman, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Jonsson, Bengt-Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Increased CO2 evolution caused by heat treatment in wood-decaying fungi2017In: Mycological progress, ISSN 1617-416X, E-ISSN 1861-8952, Vol. 16, no 5, p. 513-519Article in journal (Refereed)
    Abstract [en]

    Wood-decaying fungi are regarded as the main decomposers of woody debris in boreal forests. Given that fungal respiration makes a significant contribution to terrestrial carbon flows, it is important to understand how the wood-decaying fungal metabolism is regulated in relation to different environmental conditions and disturbances. In the present study, we investigated the effect of temperature stress on wood decomposition rate in 18 species of wood-decaying fungi, representing a broad range of species-habitat associations. Heat shock duration and temperature were calibrated to match the conditions of a forest fire. We found a general increase in fungal decay rate after heat shock; the response was more pronounced in species associated with fire-prone forests. The underlying mechanism is unclear, but possibly relates to an up-regulation at the cellular level in response to heat shock. Our results show that the decomposition rate of dead wood can be strongly affected by environmental triggers.

  • 70.
    Carlsson, Fredrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edman, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Jonsson, Bengt-Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Increased decomposition, triggered by heat shock found in wood fungiManuscript (preprint) (Other academic)
    Abstract [en]

    Wood fungi can be extremely heat resilient: several studies have shown that species can survive highly elevated temperatures relative to their growth optima. In this study we examine the effect of heat shock on subsequent decomposition rates. Sixteen species of wood fungi were tested over a period of 17 weeks. All strains were inoculated on to sterilized pine wood cylinders, placed in small bio chambers and tested twiice a week for CO2 accumulation. After 8 weeks all species were subjected to heat shock. We found that this triggered an increased decomposition rate in all species, this increase peaked 6 weeks after the shock. the peak was higher in wood fungi species that are associated with forest fires compared to specoes with no such association.

  • 71.
    Carlsson, Fredrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Koch, Christin
    Edman, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Holm, Svante
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Testing the probability of finding major decomposing basidiomycetes in logs with T-RFLP - implications for field samplingManuscript (preprint) (Other academic)
    Abstract [en]

    In this article we examine the limitations and potential of T-RFLP for the accurate detection of fungal species in dead wood. We collected cross-sections of decayed logs to evaluate the number of fungal species domains that are likely to be hit when drilling a sawdust sample from a log. We used these estimates to simulate the number of species that would be found using a certain number of samples. We found that in 99% of the simulations, 4 or fewer species would be contained in a sample. Based on these results we tested the probability of detecting two species of wood-decaying basidiomycetes at three different DNA concentration ratios: 1:1, 1:5 and 1:20. An additional experiment was done with 3-5 species. It was possible to detect all species at ratios higher than 1:20 but lower than 1:5; in this range all peaks were easily detected. We were able to detect all species in the mixtures of 3-5 species, with extracts from both pure cultures and wood.

  • 72.
    Carlsson, Fredrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Nyhlén, Sara
    Mid Sweden University, Faculty of Human Sciences, Department of Social Sciences.
    Hållbart samhällsbyggande: statsvetenskapliga och biologiska perspektiv2017In: Hållbarhetens många ansikten: samtal, forskning och fantasier / [ed] Edith Andresen, Gustav Lidén, Sara Nyhlén, Sundsvall: Mid Sweden University , 2017, p. 72-79Chapter in book (Other academic)
  • 73.
    Carlsson, Fredrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Olsson, Jörgen
    Holm, Svante
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Strong clustering in a SNP study of Phlebiopsis gigantea in swedenManuscript (preprint) (Other academic)
    Abstract [en]

    The population structures of wood decaying basidomycetes depend on several factors; one is dispersal pattern of spores, another is age structure including lifespan and also environmental impacts like forest fires. Phlebiopsis gigantea has been shown to be in the group of basidomycetes that have a well developed tolerance to heat, is long-distance wind dispersed and whose fruit body show up early in succession on fallen logs. In a study of 132 individuals from 3 pairs of locations, 350 km apart, in middle to northern Sweden we used 26 SNP-markers in 6 loci to make a genetic clustering study using STRUCTURE (v. 2.3.4.). The hypothesis; first, clustering should follow the geographic sampling locations with more gene flow between geographically close locations, second; that genetic distance between different clusters should be low due to the long distance dispersal of spores, third; as markers are random we don’t expect to find a correlation between locations affected by forest fires and locations not affected by forest fires. In the study we found 5 clusters (Pr[K= 1]) with moderate to high Fst values (0,0697-03939). Clusters had a poor geographical correlation to sampled populations indicating a complicated population structure. Out of 132 individuals 119 had a private genotype showing a large genetic variation over the total area and a low level of clones in the field.         

  • 74.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Combined heterogeneous metal/organic catalysts for eco-friendly synthesis2015In: Pure and Applied Chemistry, ISSN 0033-4545, E-ISSN 1365-3075, Vol. 87, no 9-10, p. 1011-1019Article in journal (Refereed)
    Abstract [en]

    The interplay and synergistic cooperation between homogeneous and heterogeneous catalyst systems is of utmost importance in nature. It is also applied in chemical synthesis. Here, it can allow for new reactivity, which is not possible by the employment of a single catalyst, and promote the catalysis of multiple transformations in a one-pot sequence. This could overall lead to novel reactions and the development of sustainable chemistry. In this context, a versatile and broad synergistic strategy for the selective synthesis of valuable molecules with variable complexity and under eco-friendly conditions is disclosed. It is based on integrated heterogeneous metal/organo multiple relay catalysis, which is performed in a single reaction vessel, and allows for the assembly of complex molecules (e.g., heterocycles and carbocycles) with up to three quaternary stereocenters in a highly enantioselective fashion from simple alcohols and air/O-2.

  • 75.
    Crow, Rickard
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Vidareutveckling av splitboardclips: En förbättring av design och vridstyvhet2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is a further development of split-board clips on assignment for the company Furberg Snowboards. The goal has been to create a new concept which is more rigid than the previous design, without compromising on the user interface. Through feasibility studies a number of criteria has been defined. These are based, among other things, on different load cases, the use environment and operation. With the help of sketches and the 3D modeling program Solidworks a variety of proposed solutions has been generated. These have by visual inspec-tion been culled and developed with the product tool the Pugh’s matrix until only two concepts remained. These two have then been charged with simulated forces in the software Solidworks Simulation to deter-mine how well they perform both against each other, but also to the split-board clip of the brand Voilé which is sold together with Furberg’s split-boards today. The result is a new unique concept that consists of only one moving part that can be manufactured by bending. The con-struction is in its simplicity a bracket of the aluminum alloy 7075-T6 which rotates about a fixed point, in which it is screwed in one of the split-board’s ski. Meanwhile, the bracket has two cut grooves to attach the bolts on the opposite ski. The new solution can also adjust the distance between the two skis through a newly designed adjustable washer, which is of great advantage because of the fact that the factory that manufactures the split-boards can’t drill the mounting holes with greater precision than +/- 0.5 mm. The new design has also been shown by simulation to be much more rigid than Voile’s clips.

  • 76.
    Dahlström, Christina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Faria, Gregorio C
    Department of Materials Science and Engineering, Stanford University, São Carlos Physics Institute, University of São Paulo.
    Engström, Ann-Christine
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Duong, Duc, T.
    Department of Materials Science and Engineering, Stanford University.
    Salleo, Alberto
    Department of Materials Science and Engineering, Stanford University.
    Structural Change of Cellulose Nanofibers in Supercapacitor Electrodes during Galvanostatic Cycling2015Conference paper (Other academic)
    Abstract [en]

    Graphene and other carbon-based materials are often used as electrodes in electrochemical double-layer supercapacitors (EDLCs), due to their ability to store electrical energy. Cellulose nanofibers (CNF) have been proven to be suitable as a dispersion agent and binder in graphite based electrodes for supercapacitor applications, especially due to their capability to improve the wet and dry strength of the electrode. At the same time the capacitance is maintained or even increased with addition of CNF. It is reasonable to believe that the addition of CNF manages to stabilize smaller graphite particles in the dispersion which results in larger internal surface area in the dry material.

     

    When the amount of CNF is around 20 wt%, (in ratio to the total mass of active material), both scanning electron microscopy and XPS analysis showed that the surface is almost completely covered with the nano-cellulose. Even with this isolating layer of cellulose it is interesting to note that the capacitance is as high as 90 F/g, compared to around 50 F/g for the lowest CNF amount of 5 wt%. However, by applying voltage pulses during the galvanostatic cycling procedure for capacitance measurements, an initial transient behavior is observed during the first cycles. Therefore the capacitance is calculated after 4000 charge and discharge curves, when curves are completely stabilized. We found that the electrode structure changes significantly during this capacitance measurement and already after a short pulse of 10 s and 0.3 V the structural change is noticeable. After cycling for 24 hours, a completely new structure emerges where large fiber-like structures are developed with diameters around 20-30 µm. The galvanostatic cycling procedure has created fiber-like cellulose structures around 1000 times larger than the initial size of the nano-cellulose.

     

    Structural properties of the electrode have often been related to the electronic properties in the supercapacitor. Our result shows that due to this change in the CNF structure, the electrode properties after galvanostatic cycling are indeed also of interest to study. This structural change might be critical to device performance and durability.    

  • 77.
    Dahlström, Christina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Coating Uniformity and its Effect on Supercapacitor Capacitance2014Conference paper (Other academic)
  • 78. Danilov, Andrey
    et al.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Angenete, Johan
    Optical probing in electron microscopes2010Patent (Other (popular science, discussion, etc.))
  • 79.
    Deesha, Bashar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Jiggbord: Konstruktion av hjälpmedel för tillverkning av hörnblock till prefabricerade byggnader2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Arbetets syfte var att ta fram ett konstruktionsunderlag för ett jiggbord för tillverkning av hörnblock till prefabricerade väggar. Byggföretaget Paralox AB, med patent för just dessa hörnblock, saknar en arbetsstation vid tillverkning av dessa. Konstruktionsarbetet gjordes utifrån designprocessens metod med i fyra steg, planering, utforskning av kontext, skapande av idéer och skapande av konstruktionsunderlag. Två koncept skapades, det andra som resultatet ur en idéutvärdering, en modifikation och förbättring av det första. Genom en belastningsanalys av de två viktigaste komponenterna kontrollerades att jiggbordet klarar kravspecifikationens krav. Resultatet blev ett anpassat jiggbord med enkel konstruktion och rotationsförmåga som möjliggör tillverkning av hörnblocken från start till färdig produkt.

  • 80.
    Deesha, Bashar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Optimering av fläktinstallation för att eliminera deformationer och öka kylprestanda: Volvos hjullastare L60H-L120H2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Volvo CE is one of the leading manufacturers of construction machinery, including wheel loaders. Volvo is constantly working to resolve problems and improve their products. For the L60H-L120H wheel loaders series, there are recurring problems with the cooling fan installation, during assembly as well as in operation. The problems are mainly deformations on the fan and hood. The aim of this study has therefore been to identify known problems and find constructional solutions to eliminate deformations and maintain or improve cooling performance. The changes in the design are mainly focusing on making the shroud a load-bearing structure and replacing the current console with arms to hold the fan installation in place. A 3D-model in Catia V5 has been created that meets the strength requirements that Volvo has for the fan installation. The solution has a simpler design that eliminates deformations and gives an increased cooling performance.

  • 81.
    Deiana, L.
    et al.
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden .
    Ghisu, L.
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden .
    Córdova, O.
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden .
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Zhang, Renyun
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden .
    Efficient and highly enantioselective aerobic oxidation-michael- carbocyclization cascade transformations by integrated Pd(0)-CPG nanoparticle/chiral amine relay catalysis2014In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, Vol. 46, no 10, p. 1303-1310Article in journal (Refereed)
    Abstract [en]

    A series of highly diastereo- and enantioselective aerobic oxidation-Michael-carbocyclization cascade transformations by integrated heterogeneous Pd(0)-CPG nanoparticle/chiral amine relay catalysis are disclosed. The heterogeneous Pd(0)-CPG nanoparticle catalysts were efficient for both the sequential aerobic oxidation and dynamic kinetic asymmetric Michael- carbocyclization transformations, resulting in 1) oxidation of a variety of allylic alcohols to enals and 2) formation of cyclopentenes containing an all-carbon quaternary stereocenter in good to high yields with up to 20:1 dr and 99.5:0.5 er. © Georg Thieme Verlag Stuttgart.New York.

  • 82.
    Deiana, Luca
    et al.
    Stockholm Univ, S-10691 Stockholm, Sweden.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Stockholm Univ, S-10691 Stockholm, Sweden.
    Nieto, Carlos Palo
    Stockholm Univ, S-10691 Stockholm, Sweden.
    Jiang, Yan
    Stockholm Univ, S-10691 Stockholm, Sweden.
    Johnston, Eric
    Stockholm Univ, S-10691 Stockholm, Sweden.
    Verho, Oscar
    Stockholm Univ, S-10691 Stockholm, Sweden.
    Combined multistep heterogeneous transition metal catalysis and aminocatalysis for asymmetric cascade reactions2013In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245, p. Meeting abstract 147-ORGN-Article in journal (Other academic)
  • 83.
    Deiana, Luca
    et al.
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden.
    Ghisu, Lorenza
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden.
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Verho, Oscar
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden.
    Johnston, Eric V.
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden.
    Hedin, Niklas
    Berzelii Center EXSELENT, Stockholm University, SE-106 91 Stockholm, Sweden.
    Bacsik, Zoltan
    Department of Materials and Environmental Chemistry, Stockholm University, Stockholm SE-106 91, Sweden .
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden .
    Enantioselective Heterogeneous Synergistic Catalysis for Asymmetric Cascade Transformations2014In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 356, no 11-12, p. 2485-2492Article in journal (Refereed)
    Abstract [en]

    A modular design for a novel heterogeneous synergistic catalytic system, which simultaneously activates the electrophile and nucleophile by the combined activation modes of a separate metal and non-metal catalyst, for asymmetric cascade transformations on a solid surface is disclosed. This modular catalysis strategy generates carbocycles (up to 97.5: 2.5 er) as well as spirocyclic oxindoles (97.5: 2.5 to > 99: 0.5 er), containing all-carbon quaternary centers, in a highly enantioselective fashion via a one-pot dynamic relay process.

  • 84.
    Deiana, Luca
    et al.
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden.
    Jiang, Yan
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden.
    Palo-Nieto, Carlos
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden.
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Incerti-Pradillos, Celia A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Verho, Oscar
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden.
    Tai, Cheuk-Wai
    Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden .
    Johnston, Eric V.
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden.
    Cordova, Armando
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden.
    Combined Heterogeneous Metal/Chiral Amine: Multiple Relay Catalysis for Versatile Eco-Friendly Synthesis2014In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 53, no 13, p. 3447-3451Article in journal (Refereed)
    Abstract [en]

    Herein is described a versatile and broad synergistic strategy for expansion of chemical space and the synthesis of valuable molecules (e.g. carbocycles and heterocycles), with up to three quaternary stereocenters, in a highly enantioselective fashion from simple alcohols (31examples, 95:5 to >99.5:0.5 e.r.) using integrated heterogeneous metal/chiral amine multiple relay catalysis and air/O-2 as the terminal oxidant. A novel highly 1,4-selective heterogeneous metal/amine co-catalyzed hydrogenation of enals was also added to the relay catalysis sequences.

  • 85.
    Duncan, S.
    et al.
    John Innes Centre, Norwich, United Kingdom .
    Holm, Svante
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Questa, J.
    John Innes Centre, Norwich, United Kingdom .
    Irwin, J.
    John Innes Centre, Norwich, United Kingdom .
    Grant, A.
    Department of Environmental Sciences, University of East Anglia, Norwich, United Kingdom .
    Dean, C.
    John Innes Centre, Norwich, United Kingdom .
    Seasonal shift in timing of vernalization as an adaptation to extreme winter2015In: eLIFE, ISSN 2050-084X, Vol. 4, no JULYArticle in journal (Refereed)
    Abstract [en]

    The requirement for vernalization, a need for prolonged cold to trigger flowering, aligns reproductive development with favorable spring conditions. In Arabidopsis thaliana vernalization depends on the cold-induced epigenetic silencing of the floral repressor locus FLC. Extensive natural variation in vernalization response is associated with A. thaliana accessions collected from different geographical regions. Here, we analyse natural variation for vernalization temperature requirement in accessions, including those from the northern limit of the A. thaliana range. Vernalization required temperatures above 0°C and was still relatively effective at 14°C in all the accessions. The different accessions had characteristic vernalization temperature profiles. One Northern Swedish accession showed maximum vernalization at 8°C, both at the level of flowering time and FLC chromatin silencing. Historical temperature records predicted all accessions would vernalize in autumn in N. Sweden, a prediction we validated in field transplantation experiments. The vernalization response of the different accessions was monitored over three intervals in the field and found to match that when the average field temperature was given as a constant condition. The vernalization temperature range of 0–14°C meant all accessions fully vernalized before snowfall in N. Sweden. These findings have important implications for understanding the molecular basis of adaptation and for predicting the consequences of climate change on flowering time.

  • 86.
    Eales, Jacqualyn
    et al.
    Mistra Council for Evidence-Based Environmental Management, Stockholm Environment Institute, Stockholm.
    Haddaway, Neal R.
    Mistra Council for Evidence-Based Environmental Management, Stockholm Environment Institute, Stockholm.
    Bernes, Claes
    Mistra Council for Evidence-Based Environmental Management, Stockholm Environment Institute, Stockholm.
    Cooke, Steven J.
    Department of Biology, Canadian Centre for Evidence-Based Conservation, Carleton University, 1125 Colonel By Drive, Ottawa, ON, Canada.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Kouki, Jari
    School of Forest Sciences, University of Eastern Finland-Joensuu, Yliopistokatu 7, Joensuu, Finland.
    Petrokofsky, Gill
    Department of Zoology, Tinbergen Building, South Parks Road, Oxford, United Kingdom.
    What is the effect of prescribed burning in temperate and boreal forest on biodiversity, beyond tree regeneration, pyrophilous and saproxylic species?: A systematic review protocol2016In: Environmental Evidence, ISSN 2047-2382, E-ISSN 2047-2382, Vol. 5, no 1, p. 1-8Article in journal (Refereed)
    Abstract [en]

    Background: Forests set aside from productive forestry are often considered best conserved by non-intervention. However, biodiversity is often maintained in natural forests by a background level of disturbance, which, in some forests, takes the form of forest fires. Set-aside forests may therefore benefit from continuation of such disturbances, which, in forests under protection, must be managed anthropogenically. While the effects of prescribed burning on tree regeneration and on pyrophilous and/or saproxylic species in some regions are well known, effects on other organisms are less clear and/or consistent. It would be valuable to broaden the knowledge of how prescribed burning affects forest biodiversity, particularly because this practice is increasingly considered as a conservation management intervention. The primary aim of the proposed systematic review is to clarify how biodiversity is affected by prescribed burning in temperate and boreal forests. The ultimate purpose of the review is to investigate whether and how such prescribed burning may be useful as a means of conserving or restoring biodiversity, beyond that of pyrophilous and saproxylic species, in forest set-asides. Methods: The review will examine primary field studies of how prescribed burning affects biodiversity in boreal and temperate forests. We will consider studies made in such forests anywhere in the world, and will include forests both in protected areas and under commercial management. Non-intervention will be used as a comparator. Relevant outcomes will include a range of measures of biodiversity, including abundance and diversity, but not of pyrophilous and saproxylic species. Relevant studies will be taken from a recent systematic map of the evidence on biodiversity impacts of active management in forests set aside for conservation or restoration. Additional searches and a search update will be undertaken in a subset of databases from the systematic map, using a search string targeted to identify studies focused on prescribed burning interventions. Searches for additional literature will be made in the bibliographies of existing reviews of forest burning. Traditional academic literature and grey literature in English, French, Swedish and Finnish will be considered. Stakeholders who engage in prescribed burning will be asked to provide relevant grey literature.

  • 87.
    Eales, Jacqualyn
    et al.
    Mistra EviEM, Stockholm Environment Institute, Stockholm; University of Exeter Medical School, Truro, United Kingdom.
    Haddaway, Neal R.
    Mistra EviEM, Stockholm Environment Institute, Stockholm; University of Johannesburg, Johannesburg, South Africa.
    Bernes, Claes
    Mistra EviEM, Stockholm Environment Institute, Stockholm.
    Cooke, Steven J.
    Carleton University, Ottawa, Canada.
    Jonsson, Bengt-Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Kouki, Jari
    University of Eastern Finland-Joensuu, Joensuu, Finland.
    Petrokofsky, Gillian
    University of Oxford, Oxford, United Kingdom.
    Taylor, Jessica J.
    Carleton University, Ottawa, Canada.
    What is the effect of prescribed burning in temperate and boreal forest on biodiversity, beyond pyrophilous and saproxylic species?: A systematic review2018In: Environmental Evidence, ISSN 2047-2382, E-ISSN 2047-2382, Vol. 7, no 1, article id 19Article in journal (Refereed)
    Abstract [en]

    Background: While the effects of prescribed burning on tree regeneration and on pyrophilous and/or saproxylic species are relatively well known, effects on other organisms are less clear. The primary aim of this systematic review was to clarify how biodiversity is affected by prescribed burning in temperate and boreal forests, and whether burning may be useful as a means of conserving or restoring biodiversity, beyond that of pyrophilous and saproxylic species. Methods: The review examined primary field studies of the effects of prescribed burning on biodiversity in boreal and temperate forests in protected areas or under commercial management. Non-intervention or alternate levels of intervention were comparators. Relevant outcomes were species richness and diversity, excluding that of pyrophilous and saproxylic species. Relevant studies were extracted from a recent systematic map of the evidence on biodiversity impacts of active management in forests set aside for conservation or restoration. Additional searches and a search update were undertaken using a strategy targeted to identify studies focused on prescribed burning interventions. Grey literature and bibliographies of relevant published reviews were also searched for evidence. Studies were assessed for internal and external validity and data were extracted, using validity assessment and data extraction tools specifically designed for this review. Studies were presented in a narrative synthesis and interactive map, and those which were suitable were quantitatively synthesised using meta-analyses, subgroup analysis and meta-regression. Results: Searches generated a total of 12,971 unique records. After screening for relevance, 244 studies (from 235 articles) were included in this review. Most studied forests were located in the USA (172/244), with the rest located in Canada, Europe and Australia. Eighty-two studies reporting 219 comparisons were included in the quantitative synthesis. Within the meta-analyses for each group of taxa, we identified a small to moderate volume of evidence, and heterogeneity was ubiquitous. Prescribed burning had significant positive effects on vascular plant richness, non-native vascular plant richness, and in broadleaf forests, herbaceous plant richness. Time since the burn, forest type and climate zone were significant moderators predicting the effect of burning on herbaceous plant richness. No other significant relationships were identified. Conclusions: Knowledge gaps exist for studies outside North America, in mixed forests and for non-plant organism outcomes. We identify a need to apply study designs consistently and appropriately, minimising the impact of confounding factors wherever possible, and to provide extensive detail in study reports. We recommend that researchers build long-term datasets charting the impacts of prescribed burning on succession. The lack of consistent findings was likely due to high inter-study heterogeneity, and low numbers of comparable studies in each quantitative synthesis. We found no consistent effects of moderators, and were unable to test the effect of many potential moderators, due to a lack of reporting. Rather than making any general recommendations on the use of prescribed burning for biodiversity restoration, we provide an evidence atlas of previous studies for researchers and practitioners to use. We observe that outcomes are still difficult to predict, and any restoration project should include a component of monitoring to build a stronger evidence base for recommendations and guidelines on how to best achieve conservation targets. Prescribed burning may have harmful effects on taxa that are conservation-dependent and careful planning is needed. 

  • 88.
    Edman, Mattias
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Eriksson, Anna-Maria
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Competitive outcomes between wood-decaying fungi are altered in burnt wood2016In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 92, no 6, p. 1-7Article in journal (Refereed)
    Abstract [en]

    Fire is an important disturbance agent in boreal forests where it creates a wide variety of charred and other types of heat-modified dead wood substrates, yet how these substrates affect fungal community structure and development within wood is poorly understood. We allowed six species of wood-decaying basidiomycetes to compete in pairs in wood-discs that were experimentally burnt before fungal inoculation. The outcomes of interactions in burnt wood differed from those in unburnt control wood for two species:Antrodia sinuosanever lost on burnt wood and won over its competitor in 67% of the trials compared to 40% losses and 20% wins on unburnt wood. In contrast, Ischnoderma benzoinumwon all interactions on unburnt wood compared to 33% on burnt wood. However, the responses differed depending on the identity of the competing species, suggesting an interaction between competitor and substrate type. The observed shift in competitive balance between fungal species probably results from chemical changes in burnt wood, but the underlying mechanism needs further investigation. Nevertheless, the results indicate that forest fires indirectly structure fungal communities by modifying dead wood, and highlight the importance of fire-affected dead wood substrates in boreal forests.

  • 89.
    Edman, Mattias
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Eriksson, Anna-Maria
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Villard, Marc-André
    Université de Moncton, Canada.
    The importance of large-tree retention for the persistence of old-growth epiphytic bryophyte Neckera pennata in selection harvest systems2016In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 372, p. 143-148Article in journal (Refereed)
    Abstract [en]

    Partial harvesting methods are generally more similar to the natural dynamics of broad-leaved forests than clear cutting. However, their effects on biodiversity are still poorly understood. We investigated the effects of selection cutting on the occurrence of a large epiphytic bryophyte, Neckera pennata, in a northern hardwood forest of New Brunswick, Canada. Twenty-eight forest stands were selected, repre- senting two contrasting forest management practices: 5–9 years old, first-entry selection cuts and untreated stands that had been subjected to low-intensity single-tree cutting at least 35 years earlier. Within each stand, we quantified the presence–absence of N. pennata on 36 trees and measured selected forest stand variables. Although N. pennata had persisted in post-harvest stands, its frequency of occur- rence on maple trees was only 7% there, compared to 39% in untreated stands. The density of large- diameter sugar maple trees and crown cover were the most important factors predicting the frequency of N. pennata at the stand level. Tree diameter was also a strong predictor of N. pennata’s presence at the tree level and the occupancy of large-diameter maples was almost twice as high in untreated stands as in selection cuts. However, the occupancy of large-diameter maples relative to smaller maple trees was much higher in selection cuts, possibly due to dispersal limitations resulting from reduced connectivity of large-diameter host trees. Taken together, our findings suggest that (1) large trees from older seral stages are a prerequisite for the long-term persistence of N. pennata in managed forests and that (2) they are therefore particularly important for managers to retain in selection cuts. Further, since our results indi- cate that reduced crown cover in selection cuts has a negative effect on N. pennata, the benefit of retaining large host trees would probably increase if buffered within retention patches of maturing trees. Finally, since host tree diameter clearly is a very important factor for the presence of N. pennata, any extension of the harvest rotation would be beneficial.

  • 90.
    Edman, Mattias
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Fällström, Ida
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    An introduced tree species alters the assemblage structure and functional composition of wood-decaying fungi in microcosms2013In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 306, p. 9-14Article in journal (Refereed)
    Abstract [en]

    Although it is widely recognized that introduced plant species produce organic matter of different quality surprisingly little is known about how this influence the community structure of decomposers. Here, we investigated the effects of a commercial non-native tree species, lodgepole pine, on the community structure of wood-decaying basidiomycetes and the decomposition of deadwood in northern Sweden. We allowed an assemblage of wood-decaying fungi that occur naturally on pine to interact on fresh wooddiscs of lodgepole pine and Scots pine, using microcosms. At the end of the experiment we measured the wood mass loss and calculated the area of the different species' domains as indicated by interaction zone lines between competing species. Fungal assemblage structure developed in a markedly different way on lodgepole pine compared to Scots pine. In addition to there being fewer species in the final fungal assemblage on lodgepole pine, fungal functional composition was different. White-rot fungi were more competitive and dominated on lodgepole pine, while brown-rot fungi dominated on Scots pine. We also found that the decay rate of lodgepole pine wood was slightly lower, although the underlying reason remains unclear. However, there was a significant positive relationship between the abundance of white-rot fungi and the wood mass loss of lodgepole pine, while no relationship was found between fungal functional group and the decay rate of Scots pine. We also found no relationship between species richness and wood decay rates. Our study reveals that a non-native tree species used in commercial forestry can alter the structure and functional composition of a saprotrophic wood-decaying fungal assemblage. Future studies are required to clarify the mechanisms behind the observed patterns and whether they apply to natural systems.

  • 91.
    Edström, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Made in Sweden – Future Textiles and Paper: Strategic research and innovation agenda for the joint paper and textile industries in Sweden2013Other (Other (popular science, discussion, etc.))
  • 92.
    Edvardsson, Sverker
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Karlsson, Kristoffer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Science Education and Mathematics.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    corr3p_tr: A particle approach for the general three-body problem2016In: Computer Physics Communications, ISSN 0010-4655, E-ISSN 1879-2944, Vol. 200, p. 259-273Article in journal (Refereed)
    Abstract [en]

    This work presents a convenient way to solve the non-relativistic Schrodinger equation numerically for a general three-particle system including full correlation and mass polarization. Both Coulombic and non-Coulombic interactions can be studied. The eigensolver is based on a second order dynamical system treatment (particle method). The Hamiltonian matrix never needs to be realized. The wavefunction evolves towards the steady state solution for which the Schrodinger equation is fulfilled. Subsequent Richardson extrapolations for several meshes are then made symbolically in matlab to obtain the continuum solution. The computer C code is tested under Linux 64 bit and both double and extended precision versions are provided. Test runs are exemplified and, when possible, compared with corresponding values in the literature. The computer code is small and self contained making it unusually simple to compile and run on any system. Both serial and parallel computer runs are straight forward. Program summary Program title: corr3p_tr Catalogue identifier: AEYR_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEYR_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.ukilicence/licence.html No. of lines in distributed program, including test data, etc.: 15025 No. of bytes in distributed program, including test data, etc.: 156430 Distribution format: tar.gz Programming language: ANSI C. Computer: Linux 64bit PC. Operating system: Linux 64bit. RAM: 300 M bytes Classification: 2.7, 2.8, 2.9. Nature of problem: The Schrodinger equation for an arbitrary three -particle system is solved using finite differences and a fast particle method for the eigenvalue problem [20, 21, 23]. Solution method: A fast eigensolver is applied (see Appendix). This solver works for both symmetrical and nonsymmetrical matrices (which opens up for more accurate nonsymmetrical finite difference expressions to be applied at the boundaries). The three-particle Schrodinger equation is transformed in two major steps. First step is to introduce the function Q(r(1), (r)2, mu) = r(1)r(2)(1 - mu(2))phi(r(1), r(2), mu), where mu = cos (0(12)). The cusps (r(1) = r(2), mu = 1) are then transformed into boundary conditions. The derivatives of Qare then continuous in the whole computational space and thus the finite difference expressions are well defined. Three-particle coalescence (r(1) = r(2) = 0, mu) is treated in the same way. The second step is to replace Q(r(1), r(2), mu) with (2,root x(1)x(2))(-1)Q(x(1) x(2), mu). The space (x(1), x(2), mu) is much more appropriate for a finite difference approach since the square roots x(1) = root r(1), x(2) = root r(2) allow the boundaries to be much further out. The non-linearity of the x-grid also leads to a finer description near the nucleus and a coarser one further out thus resulting in a saving of grid points. Also, in contrast to the usual variable r(12), we have instead used mu which is an independent variable. This simplifies the mathematics and numerical treatments. Several different grids can naturally run completely independent of each other thus making parallel computations trivial. From several grid results the physical property of interest is extrapolated to continuum space. The extrapolations are made in a matlab m-script where all computations can be made symbolically so the loss of decimal figures are minimized during this process. The computer code, including correlation effects and mass polarization, is highly optimized and deals with either triangular or quadratic domains in (x(1), x(2)). Restrictions: The amount of CPU time may become unreasonable for states needing boundary conditions very far beyond the origin. Also if the condition number of the corresponding Hamiltonian matrix is very high, the number of iterations will grow. The use of double precision computations also puts a limit on the accuracy of extrapolated results to about 6-7 decimal figures. Unusual features: The numerical solver is based on a particle method presented in [20, 21, 23]. In the Appendix we provide specific details of dealing with eigenvalue problems. The program uses a 64 bit environment (Linux 64bit). Parallel runs can be made conveniently through a simple bash script. Additional comments: The discretized wavefunction is complete on every given grid. New interactions can therefore conveniently be added to the Hamiltonian without the need to seek for an appropriate basis set. Running time: Given a modern CPU such as Intel core i5 and that the outer boundary conditions of r(1) and r(2) is limited to, say 16 atomic units, the total CPU time of totally 10 grids of a serial run is typically limited to a few minutes. One can then expect about 6-7 correct figures in the extrapolated eigenvalue. A single grid of say h(1) = h(2) = h(3) = 1/16 converges in less than 1 s (with an error in the eigenvalue of about 1 percent). Parallel runs are possible and can further minimize CPU times for more demanding tasks. References: [20] S. Edvardsson, M. Gulliksson, and J. Persson.). Appl. Mech. ASME, 79 (2012) 021012. [21] S. Edvardsson, M. Neuman, P Edstrom, and H. Olin. Comp. Phys. Commun. 197 (2015) 169. [23] M. Neuman, S. Edvardsson, P. Edstrom, Opt. Lett. 40 (2015) 4325.

  • 93.
    Edvardsson, Sverker
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Neuman, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edström, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Gulliksson, Mårten
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Role of the particle method DFPM for solving linear equationsManuscript (preprint) (Other academic)
  • 94.
    Edvardsson, Sverker
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Neuman, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edström, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Solving equations through particle dynamics2015In: Computer Physics Communications, ISSN 0010-4655, E-ISSN 1879-2944, Vol. 197, p. 169-181Article in journal (Refereed)
    Abstract [en]

    The present work evaluates a recently developed particle method (DFPM). The basic idea behind this method is to utilize a Newtonian system of interacting particles that through dissipation solves mathematical problems. We find that this second order dynamical system results in an algorithm that is among the best methods known. The present work studies large systems of linear equations. Of special interest is the wide eigenvalue spectrum. This case is common as the discretization of the continuous problem becomes dense. The convergence rate of DFPM is shown to be in parity with that of the conjugate gradient method, both analytically and through numerical examples. However, an advantage with DFPM is that it is cheaper per iteration. Another advantage is that it is not restricted to symmetric matrices only, as is the case for the conjugate gradient method. The convergence properties of DFPM are shown to be superior to the closely related approach utilizing only a first order dynamical system, and also to several other iterative methods in numerical linear algebra. The performance properties are understood and optimized by taking advantage of critically damped oscillators in classical mechanics. Just as in the case of the conjugate gradient method, a limitation is that all eigenvalues (spring constants) are required to be of the same sign. DFPM has no other limitation such as matrix structure or a spectral radius as is common among iterative methods. Examples are provided to test the particle algorithm’s merits and also various performance comparisons with existent numerical algorithms are provided.

  • 95.
    Eivazihollagh, Alireza
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Bäckström, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Carlsson, Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Ibrahem, Ismail
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lindman, Björn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    One-pot synthesis of cellulose-templated copper nanoparticles with antibacterial properties2017In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 187, p. 170-172Article in journal (Refereed)
    Abstract [en]

    We report a facile in situ synthesis of spherical copper nanoparticles (NPs) templated by a gelled cellulose II matrix under alkaline aqueous reaction conditions. In under 20 min, the hybrid material could be obtained in a one-pot reaction. Field-emission scanning electron microscopy (FE-SEM) revealed that the polycrystalline NPs of 200–500 nm were well distributed in the regenerated cellulose matrix. The average Cu crystallite size was of the order of 20 nm, as estimated from both X-ray diffraction (XRD) and FE-SEM. XRD data also indicated that the composite contained up to approximately 20% Cu2O. In suspensions containing the hybrid material, growth of Escerichia coli and Staphylococcus aureus strains was inhibited by 80% and 95%, respectively, after 72 h. The synthesis procedure offers a general approach to designing various low-cost hybrid materials of almost any shape, and the concept could be extended to utilization areas such as catalysis, functional textiles, and food packaging as well as to electronic applications.

  • 96.
    Eivazihollagh, Alireza
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Bäckström, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Electrochemical recovery of copper complexed by DTPA and C12-DTPA from aqueous solution using a membrane cell2018In: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 93, no 5, p. 1421-1431Article in journal (Refereed)
    Abstract [en]

    BACKGROUND

    The electrochemical recovery of copper from DTPA and C12-DTPA (a surface-active derivative of DTPA) complex solutions was investigated in a membrane flow cell. Electrolysis time, solution flow rate, applied current density, and solution pH were evaluated.

    RESULTS

    The chelating surfactant C12-DTPA can promote the kinetics of copper electrodeposition more than DTPA depending on the experimental conditions. At a current density of 30 A m–2, a solution flow rate of 0.6 L min–1, and pH 10 after 180 min treatment, the copper recovery and current efficiency were 50% and 43.3%, respectively, in the Cu(II)-DTPA system and about 65% and 53.6%, respectively, in the Cu(II)-C12-DTPA system. The differences in the amount of recovery could be explained in terms of differences in the diffusion of copper complexes with DTPA and C12-DTPA to the cathode, as well as their solution behavior and pH-dependent conditional stability constants (log10 K’CuDTPA3-).

    CONCLUSION

    Electrochemical methods could be effectively combined with foam flotation for the chelating surfactant C12-DTPA, to recover copper and C12-DTPA. This makes the overall treatment more sustainable, and can be helpful in complying with the increasingly stringent environmental regulations

  • 97.
    Eivazihollagh, Alireza
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Bäckström, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Influences of the operational variables on electrochemical treatment of chelated Cu(II) in alkaline solutions using a membrane cell2017In: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 92, no 6, p. 1436-1445Article in journal (Refereed)
    Abstract [en]

    BACKGROUND

    The electrochemical recovery of copper and chelating agent from their complex solution using a membrane flow cell was investigated. The parameters electrolysis time, solution pH, current density, and temperature were investigated.

    RESULTS

    Electrochemical investigation indicated that chelating ligands can be recovered by the electrodeposition of copper ions on the cathode. For copper and EDTA recovery, the results indicated that recovery efficiency was affected by time, current density, and temperature. The recovery process was not influenced by pH in the range studied (pH 8–12), which can be explained by the low variation in the conditional stability constant, i.e. Δlog10 K' ≤ 0.7, over the pH range. However, when NTA, EDTA, and DTPA were compared, the results indicated that the recovery efficiency decreased as the conditional stability constant of the chelating agent–Cu(II) complex increased. The maximum current efficiency of copper and EDTA recovery after 5 h of treatment was approximately 85%, whereas the recovery was 80% of the initial concentration (0.05 mol L−1) at a current density of 1 A dm−2, temperature of 333 K, and pH of 10.

    CONCLUSION

    Relatively high recovery efficiency makes the process fairly sustainable and hinders the discharge of copper ions and chelating ligands as pollutants into the environment. 

  • 98.
    Ekström, Magnus
    et al.
    Umeå University, Umeå.
    Esseen, P. -A
    Umeå University, Umeå.
    Westerlund, B.
    Swedish University of Agricultural Sciences, Umeå.
    Grafström, A.
    Swedish University of Agricultural Sciences, Umeå.
    Jonsson, Bengt-Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Ståhl, G.
    Swedish University of Agricultural Sciences, Umeå.
    Logistic regression for clustered data from environmental monitoring programs2018In: Ecological Informatics, ISSN 1574-9541, E-ISSN 1878-0512, Vol. 43, p. 165-173Article in journal (Refereed)
    Abstract [en]

    Large-scale surveys, such as national forest inventories and vegetation monitoring programs, usually have complex sampling designs that include geographical stratification and units organized in clusters. When models are developed using data from such programs, a key question is whether or not to utilize design information when analyzing the relationship between a response variable and a set of covariates. Standard statistical regression methods often fail to account for complex sampling designs, which may lead to severely biased estimators of model coefficients. Furthermore, ignoring that data are spatially correlated within clusters may underestimate the standard errors of regression coefficient estimates, with a risk for drawing wrong conclusions. We first review general approaches that account for complex sampling designs, e.g. methods using probability weighting, and stress the need to explore the effects of the sampling design when applying logistic regression models. We then use Monte Carlo simulation to compare the performance of the standard logistic regression model with two approaches to model correlated binary responses, i.e. cluster-specific and population-averaged logistic regression models. As an example, we analyze the occurrence of epiphytic hair lichens in the genus Bryoria; an indicator of forest ecosystem integrity. Based on data from the National Forest Inventory (NFI) for the period 1993–2014 we generated a data set on hair lichen occurrence on >100,000 Picea abies trees distributed throughout Sweden. The NFI data included ten covariates representing forest structure and climate variables potentially affecting lichen occurrence. Our analyses show the importance of taking complex sampling designs and correlated binary responses into account in logistic regression modeling to avoid the risk of obtaining notably biased parameter estimators and standard errors, and erroneous interpretations about factors affecting e.g. hair lichen occurrence. We recommend comparisons of unweighted and weighted logistic regression analyses as an essential step in development of models based on data from large-scale surveys. 

  • 99.
    Engstrand, Per
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Carlberg, T.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hellström, Lisbeth M.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Gradin, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Gregersen, Øyvind Weiby
    NTNU - Norges teknisk-naturvitenskapelige universitet.
    Method for producing and processing wood chips [Förfarande för framställning av flis]2011Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    This patent application describes a method to produce wood chips with the intention of reducing the energy consumption in the subsequent process steps for pulp production. With the present method wood chipping is done in a wood chipper where the chipping tool (3) has an angle γ (4) within the interval of 75° to 105° between the fibre direction of the log and the side of the tool which faces the chip (2). Angles in this interval will cause an axially directed compression of the chip which will cause a cracking of the wood during chipping.

  • 100.
    Engstrand, Per
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Gradin, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hellström, Lisbeth
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Carlberg, Torbjörn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sandström, Peter
    SCA Reseach.
    Liden, Joar
    SCA Ortviken.
    Söderberg, Mats
    SCA Research.
    Mats, Egnell
    Andritz Iggesund Tools.
    Improved refining energy efficiency in thermo-mechanical pulping by means of collimated wood chipping – from solid mechanics to full scale evaluation2016In: PaperWeek Canada 2016 Conference February 1 to 5, 2016, Montreal: Technical Track Program / [ed] Greg Hay, 2016Conference paper (Refereed)
    Abstract [en]

    The wood chipping process was never optimized with regard to high yield pulping processes as thermomechanical pulping (TMP) and chemithermomechanical pulping (CTMP). It is generally believed that wood chips for pulping should be produced in such a way that the degree of damage is minimized and that the chip dimensional distribution should be as narrow as possible. Since the TMP and CTMP processes were developed in the 60-ies and 70-ies, compression screw as well as roll nip equipment have been developed to pretreat wood chips as a way to reduce refining energy consumption to given fiber and pulp properties and also in order to improve impregnation. The general conclusions are that a combination of shear and compression in the tangential or radial direction of the wood initiates cracks that later in the refiner will enhance and optimize fiber separation and also fiber property development. The idea with the collimated chipping technology is to utilize the wood chipper as a tool, combining cutting of wood logs to wood chips with a pretreatment of the chips by creating cracks that would enhance fiber separation, fiber surface development as well as chip-impregnation. In this case the compression is performed in the wood fiber direction, in which direction wood actually is weakest when it comes to compression induced cracking. The maximization of the amount of cracks in wood-chips is performed by optimizing the knife angle (or spout angle) in the chipper, to what we call collimated chipping (according to a patent owned by CCT AB). This presentation describes a theoretical background and two demonstration scale studies performed by SCA Forest Products at their Ortviken mill. One conclusion drawn, based on two-month test period with three weeks of collimated chipping, was that specific refining energy reduction was around 100 kWh/adt of the 1400 kWh/adt used in primary stage double disc refining. Most probably the potential is higher if the whole system is optimized. Tests were performed at constant production rate and energy was reduced by reducing power to constant freeness, leading to similar tensile and light scattering levels. The deliberately increased forces created in the wood chipper by means of an optimized (increased) edge angle caused more problems with knife holder equipment than normally, as well as increased vibrations. These problems will have to be solved for future long-term implementation of the technique.

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