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  • 1.
    Adelholt, Martin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Production preparations of Hydra Coupler: Preparations, Planning, Calculations2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 2.
    Adelholt, martin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Production preparations of Hydra Coupler: Preparations, Planning, Calculations2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 3.
    Afewerki, Samson
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Stockholm University, Stockholm.
    Wang, J. -X
    Jilin University, Changchun, China.
    Liao, W. -W
    Jilin University, Changchun, China.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Stockholm University, Stockholm.
    The Chemical Synthesis and Applications of Tropane Alkaloids2019In: Alkaloids: Chemistry and Biology, ISSN 1099-4831, Vol. 81, p. 151-233Article in journal (Refereed)
    Abstract [en]

    Tropanes are an important class of alkaloid natural products that are found in plants all over the world. These compounds can exhibit significant biological activity and are among the oldest known medicines. In the early 19th century, tropanes were isolated, characterized, and synthesized by notable chemical researchers. Their significant biological activities have inspired tremendous research efforts toward their synthesis and the elucidation of their pharmacological activity both in academia and in industry. In this chapter, which addresses the developments in this field since 1994, the focus is on the synthesis of these compounds, and several examples of sophisticated synthetic protocols involving both asymmetric and catalytic approaches are described. In addition, the structures of more than 100 new alkaloids are included as well as the applications and pharmacological properties of some tropane alkaloids. 

  • 4.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Šuly, Pavol
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. Tomas Bata University in Zlin, Zlin, Czech Republic.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Engholm, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Zhang, Renyun
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Mašlík, Jan
    Tomas Bata University in Zlin, Zlin, Czech Republic.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    PEDOT: PSS thermoelectric generators printed on paper substrates2019In: Journal of Low Power Electronics and Applications, ISSN 2079-9268, Vol. 9, no 2Article in journal (Refereed)
    Abstract [en]

    Flexible electronics is a field gathering a growing interest among researchers and companies with widely varying applications, such as organic light emitting diodes, transistors as well as many different sensors. If the circuit should be portable or off-grid, the power sources available are batteries, supercapacitors or some type of power generator. Thermoelectric generators produce electrical energy by the diffusion of charge carriers in response to heat flux caused by a temperature gradient between junctions of dissimilar materials. As wearables, flexible electronics and intelligent packaging applications increase, there is a need for low-cost, recyclable and printable power sources. For such applications, printed thermoelectric generators (TEGs) are an interesting power source, which can also be combined with printable energy storage, such as supercapacitors. Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), or PEDOT:PSS, is a conductive polymer that has gathered interest as a thermoelectric material. Plastic substrates are commonly used for printed electronics, but an interesting and emerging alternative is to use paper. In this article, a printed thermoelectric generator consisting of PEDOT:PSS and silver inks was printed on two common types of paper substrates, which could be used to power electronic circuits on paper. 

  • 5.
    Ashraf, Shakeel
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Forsberg, Viviane
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. KTH, Wallenberg Wood Science Center, Stockholm.
    Mattsson, Claes G.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Thermoelectric properties of n-type molybdenum disulfide (MoS2) thin film by using a simple measurement method2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 21, article id 3521Article in journal (Refereed)
    Abstract [en]

    In this paper, a micrometre thin film of molybdenum disulfide (MoS2) is characterized for thermoelectric properties. The sample was prepared through mechanical exfoliation of a molybdenite crystal. The Seebeck coefficient measurement was performed by generating a temperature gradient across the sample and recording the induced electrical voltage, and for this purpose a simple measurement setup was developed. In the measurement, platinum was utilized as reference material in the electrodes. The Seebeck value of MoS2 was estimated to be approximately -600 μV/K at a temperature difference of 40 °C. The negative sign indicates that the polarity of the material is n-type. For measurement of the thermal conductivity, the sample was sandwiched between the heat source and the heat sink, and a steady-state power of 1.42Wwas provided while monitoring the temperature difference across the sample. Based on Fourier's law of conduction, the thermal conductivity of the sample was estimated to be approximately 0.26 Wm-1 K-. The electrical resistivity was estimated to be 29 W cm. The figure of merit of MoS2 was estimated to be 1.99 × 10-4. 

  • 6.
    Bayat, Nazlin
    et al.
    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.
    Cieslar, M.
    Charles University, Prague, Czech Republic.
    In-Situ Study of Phase Transformations during Homogenization of 6060 and 6063 Al Alloys2019In: Journal of Physics and Chemistry of Solids, ISSN 0022-3697, E-ISSN 1879-2553, Vol. 130, p. 165-171Article in journal (Refereed)
  • 7.
    Bergvall, Hannah
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Produkt för rullstolsburnas minskande olycksrisk2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 8.
    Blomquist, Nicklas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Large-Scale Graphene Production for Environmentally Friendly and Low-Cost Energy Storage: Production, Coating, and Applications2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    There is great demand for energy-efficient, environmentally sustainable, and cost-effective electrical energy storage devices. One important aspect of this demand is the need for automotive electrification to achieve more energy-efficient transportation at a reasonable cost, thus supporting a fossil-fuel free society. Another important aspect is the requirement for energy storage in the growing field of renewable energy production from wind and solar sources, which generates an irregular supply of electricity due to weather conditions.Much of the research in this area has been conducted in the field of battery technology with impressive results, but the need for rapid storage devices such as supercapacitors is growing. Due to the excellent ability of supercapacitors to handle short peak power pulses with high efficiency along with their long lifetime and superior cyclability, their implementations range from small consumer electronics to electric vehicles and stationary grid applications. Supercapacitors also have the potential to complement batteries to improve pulse efficiency and lifetime of the system, however, the cost of supercapacitors is a significant issue for large-scale commercial use, leading to a demand for sustainable, low-cost materials and simplified manufacturing processes. An important way to address this need is to develop a cost-efficient and environment-friendly large-scale process to produce highly conductive nanographites, such as graphene and graphite nanoplatelets, along with methods to manufacture low-cost electrodes from large area coating.

    In this thesis, I 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. The process is based on hydrodynamic tube-shearing and can produce both multilayer graphene and nanometer-thick and micrometer-wide flakes of nanographite. I also describe the production of highly conductive and robust carbon composites based on the addition of nanocellulose during production; these are suitable as electrodes in applications ranging from supercapacitors and batteries to printed electronics and solar cells.Furthermore I demonstrate a scalable route for roll-to-roll coating of the nanographite-nanocellulose electrode material and propose a novel aqueous, low-cost, and metal-free supercapacitor concept with graphite foil functioning as the current collector. The supercapacitors possessedmore than half the specific capacitance of commercial units but achieved a material cost reduction of more than 90 %, demonstrating anenvironment-friendly, low-cost alternative to conventional supercapacitors.

  • 9.
    Blomquist, Nicklas
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Alimadadi, Majid
    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.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Olsen, Martin
    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.
    Effects of Geometry on Large-scale Tube-shear Exfoliation of Multilayer Graphene and Nanographite in Water2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, no 1, article id 8966Article in journal (Refereed)
    Abstract [en]

    Industrially scalable methods for the production of graphene and other nanographites are needed to achieve cost-efficient commercial products. At present, there are several available routes for the production of these materials but few allow large-scale manufacturing and environmentally friendly low-cost solvents are rarely used. We have previously demonstrated a scalable and low-cost industrial route to produce nanographites by tube-shearing in water suspensions. However, for a deeper understanding of the exfoliation mechanism, how and where the actual exfoliation occurs must be known. This study investigates the effect of shear zone geometry, straight and helical coil tubes, on this system based on both numerical simulation and experimental data. The results show that the helical coil tube achieves a more efficient exfoliation with smaller and thinner flakes than the straight version. Furthermore, only the local wall shear stress in the turbulent flow is sufficient for exfoliation since the laminar flow contribution is well below the needed range, indicating that exfoliation occurs at the tube walls. This explains the exfoliation mechanism of water-based tube-shear exfoliation, which is needed to achieve scaling to industrial levels of few-layer graphene with known and consequent quality.

  • 10.
    Blomquist, Nicklas
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Koppolu, R.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Toivakka, M.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Influence of Substrate in Slot-die Coating of Nanographite/Nanocelluose Electrodes for SupercapacitorsManuscript (preprint) (Other academic)
  • 11.
    Book, Max
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Framtagning av konceptuell planetväxel inom fordonsindustrin2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 12.
    Cordova, Armando
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Alimohammadzadeh, Rana
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sanhueza, Italo
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Tai, Cheuk-Wai
    Stockholm University, Stockholm.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Ibrahem, Ismail
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    A sustainable strategy for production and functionalization of nanocelluloses2019In: Pure and Applied Chemistry, ISSN 0033-4545, E-ISSN 1365-3075, Vol. 91, no 5, p. 865-874Article in journal (Refereed)
    Abstract [en]

    A sustainable strategy for the neat production and surface functionalization of nanocellulose from wood pulp is disclosed. It is based on the combination of organocatalysis and click chemistry ("organoclick" chemistry) and starts with nanocellulose production by organic acid catalyzed hydrolysis and esterification of the pulp under neat conditions followed by homogenization. This nanocellulose fabrication route is scalable, reduces energy consumption and the organic acid can be efficiently recycled. Next, the surface is catalytically engineered by "organoclick" chemistry, which allows for selective and versatile attachment of different organic molecules (e.g. fluorescent probes, catalyst and pharmaceuticals). It also enables binding of metal ions and nanoparticles. This was exemplified by the fabrication of a heterogeneous nanocellulose-palladium nanoparticle catalyst, which is used for Suzuki cross-coupling transformations in water. The disclosed surface functionalization methodology is broad in scope and applicable to different nanocelluloses and cellulose based materials as well.

  • 13.
    Ekenberg, Greta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Utveckling av verktyg för rullbyte hos bandtransportör2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 14.
    Fahmida Zaman, Irin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Wood decaying fungi gain competitive strength through competition2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 15.
    Forsberg, Viviane
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Liquid-Phase Exfoliation of Two-Dimensional Materials: Applications, deposition methods and printed electronics on paper2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    After the unprecedented success of graphene research, other materials that can also be exfoliated into thin layers, like Transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2), have also become the subjects of extensive studies. As one of the most promising methods for large scale production of such materials, liquid-phase exfoliation (LPE) has also been the subject of extensive research and is maturing as a field to the point that devices using additive manufacturing and printed nanosheets are often reported. The stability of the nanosheets in environmentally friendly solvents, particularly in water, with or without stabilizers, is still a focus of great interest for sustainable and commercial production. In this thesis, different methods of LPE in water with and without stabilizers are investigated and discussed. Stabilizers such as surfactant sodium dodecyl sulfate (SDS) and modified cellulose2-hydroxyethyl cellulose (HEC), were employed. Because waterdoes not have surface energy parameters that match those of2D materials, the dispersions in water do not usually have a high yield. Therefore, to circumvent the use of organic solvents that are known to be able to successfully exfoliate and stabilize nanosheets of two-dimensional materials, this thesis focuses on water as the solution-process medium for exfoliation and the assisting stabilizers used to keep the exfoliated nanomaterials in dispersion with a long half-time. Surfactant-assisted dispersions are discussed together with test-printing resultsusing inkjet to deposit the material. Process parameters for the LPE method using HEC as a stabilizer are presented together with thin nanosheets characterized by Raman spectroscopy. Dispersions using HEC presented the longest half-time among the studied methods, higher than previously reported values for methods using mixed low-boiling-point solvents. Devices using exfoliated nanosheets have been fabricated and presented in the present study. The photoconductivity of MoS2 using a device fabricated with LPE MoS2 nanosheets and the cathodoluminescence of LPE MoS2 are discussed. Although fabricated with mechanically exfoliated nanosheets and not LPE ones, another photodetector fabricated with one of the MoS2 grades used in this thesis is presented to highlight the excellent photoresponse of this material. A method of producing thin nanosheets with-out stabilizers by pre-processing the MoS2 grades withs and papers is introduced. With this method, nanosheets with a lateral size of around 200nm and a concentration around 0.14 g L−1 - that is half the concentration at the same processing conditions in solvent n-methyl pyrrolidone (NMP) - are discussed. Inkjet printing as a deposition method is discussed together with the requirements for the 2D inks. Printed organic electronics using the conductive polymer PEDOT:PSS are compared to those using commercially-available graphene ink, with a focus on printing on paper substrates. In order to bring the thesis into perspective from materials to device fabrication, I study the suitability of inkjet paper substrates for printed electronics, by extensively characterizing the chemical and physical properties of their ink-receiving layers (IRLs) and their impact on the electronic properties of the conductive printed lines.

  • 16.
    Forsberg, Viviane
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Process parameters of liquid-phase exfoliation of MoS2 in waterstabilized with 2-hydroxyethyl celluloseManuscript (preprint) (Other academic)
  • 17.
    Forsberg, Viviane
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. KTH, Stockholm; Wallenberg Wood Science Centre, Stockholm.
    Mašlík, Jan
    Tomas Bata University in Zlín, Zlín, Czech Republic.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Electronic performance of printed PEDOT:PSS lines correlated to the physical and chemical properties of coated inkjet papers2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 41, p. 23925-23938Article in journal (Refereed)
    Abstract [en]

    PEDOT:PSS organic printed electronics chemical interactions with the ink-receiving layer (IRL) of monopolar inkjet paper substrates and coating color composition were evaluated through Raman spectroscopy mapping in Z (depth) and (XY) direction, Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDS). Other evaluated properties of the IRLs were pore size distribution (PSD), surface roughness, ink de-wetting, surface energy and the impact of such characteristics on the electronics performance of the printed layers. Resin-coated inkjet papers were compared to a multilayer coated paper substrate that also contained an IRL but did not contain the plastic polyethylene (PE) resin layer. This substrate showed better electronic performance (i.e., lower sheet resistance), which we attributed to the inert coating composition, higher surface roughness and higher polarity of the surface which influenced the de-wetting of the ink. The novelty is that this substrate was rougher and with somewhat lower printing quality but with better electronic performance and the advantage of not having PE in their composite structure, which favors recycling. © 2019 The Royal Society of Chemistry.

  • 18.
    Grafström, Anton
    et al.
    Swedish Univ Agr Sci, Umeå.
    Ekström, Magnus
    Swedish Univ Agr Sci, Umeå; Umeå Univ, Umeå.
    Jonsson, Bengt-Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Esseen, Per-Anders
    Umeå Univ, Umeå.
    Stahl, Göran
    Swedish Univ Agr Sci, Umeå.
    On combining independent probability samples2019In: Survey Methodology, ISSN 0714-0045, E-ISSN 1492-0921, Vol. 45, no 2, p. 349-364Article in journal (Refereed)
    Abstract [en]

    Merging available sources of information is becoming increasingly important for improving estimates of population characteristics in a variety of fields. In presence of several independent probability samples from a finite population we investigate options for a combined estimator of the population total, based on either a linear combination of the separate estimators or on the combined sample approach. A linear combination estimator based on estimated variances can be biased as the separate estimators of the population total can be highly correlated to their respective variance estimators. We illustrate the possibility to use the combined sample to estimate the variances of the separate estimators, which results in general pooled variance estimators. These pooled variance estimators use all available information and have potential to significantly reduce bias of a linear combination of separate estimators.

  • 19.
    Grafström, Anton
    et al.
    SLU, Umeå.
    Ekström, Magnus
    Umeå universitet, Umeå; SLU, Umeå.
    Jonsson, Bengt-Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Esseen, Per-Anders
    Umeå universitet, Umeå.
    Ståhl, Göran
    SLU, Umeå.
    On combining independent probability samples2019In: Survey Methodology, ISSN 0714-0045, E-ISSN 1492-0921, Vol. 45, no 2, p. 371-387Article in journal (Refereed)
    Abstract [en]

    Merging available sources of information is becoming increasingly important for improving estimates ofpopulation characteristics in a variety of fields. In presence of several independent probability samples from afinite population we investigate options for a combined estimator of the population total, based on either a linearcombination of the separate estimators or on the combined sample approach. A linear combination estimatorbased on estimated variances can be biased as the separate estimators of the population total can be highlycorrelated to their respective variance estimators. We illustrate the possibility to use the combined sample toestimate the variances of the separate estimators, which results in general pooled variance estimators. Thesepooled variance estimators use all available information and have potential to significantly reduce bias of a linearcombination of separate estimators.

  • 20.
    Hailegebreal, Ermias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Utveckling av mobil dockning för en tvåarmad robot2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    MTEK Industry är ett företag som utvecklar färdiga produktionslinjer till företag runt om i världen. En del av produktionslösningen bygger på användandet av roboten YuMi som är utvecklad av ABB. Då MTEK vill erbjuda en så flexibel lösning som möjligt har de utvecklat en fastsättningsmetod som fäster roboten mot arbetsbänken med hjälp av elektromagnetiska plattor; en mobil dockningsmetod. Den befintliga lösningen har dock ett spel i axiell led på grund av konstruktionen vilket påverkar precisionen för roboten negativt. Målet för projektarbetet har därmed varit att utveckla en ny fastsättningsmetod med förbättrad tolerans. Förundersökningen har utförts med hjälp av litteraturstudier, analys av befintlig fastsättningsmetod, löpande intervjuer med handledare och VD på MTEK samt en studie av liknande fastsättningsmetoder. Den bidrog med kunskap inför den konceptgenererande fasen som utfördes med hjälp av brainstorming och sållning. En konstruktion och simulation av konceptet utfördes i SolidWorks där en slutgiltig produkt sedan kunde produceras och analyseras. Förundersökningen visade att det idag enbart finns en liknande lösning för mobil dockning av robotar, Opiflex Automations lösning ”System for docking of a movable platform”. Dockningsmetoden som använder sig av styrpinnar är patenterad vilket resulterade i att många idéer till ett koncept för MTEK inte gick att använda då de inte uppfyllde kraven som hade ställts. Istället för ett helt nytt koncept utvecklades deras befintliga dockningsmetod som resulterade i ett slutkoncept med en förbättrad tolerans på nästan 10 gånger. Konceptet uppfyllde samtliga krav som var ställda från MTEK och anses därmed som lyckat. 

  • 21.
    Hellström, Douglas
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sundström, Simon
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Standardisering av OQL-200 systemet: Konstruktion av automatiskt snabbfästessystem för hjullastare2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Målet med denna undersökning har varit att konstruera ett standardiserat snabbfäste som passar rörelsemönstret hos minst fyra hjullastare med en tjänstevikt upp till åtta ton. Snabbfästet ska konstrueras med ett helt standardiserat redskapsfäste. Snabbfästet ska ges möjlighet till små dimensions-förändringar som ska underlätta för konstruktörsarbetet på OilQuick. En tidsplan och en kravspecifikation sattes upp, följt av en marknadsundersökning på hjullastare och snabbfästen. Fem hjullastare mättes och modellera-des digitalt. Genom geometrierna hos hjullastarna beräknades relevant maskindata såsom den maximala momentkraften kring nedre infästningen på snabbfästet. Detta presenterades i en tabell. Konceptutvecklingen inleddes med att presentera begränsningar i modelleringen genom att bestämma in-fästningspunkter på maskiner och de standardiserade måtten på redskaps-fästet. Under konceptutvecklingen togs fyra koncept fram där samtliga koncept skulle tillåta maskinernas rörelsemönster. Koncepten utvärderades ge-nom Concept Scoring som utgick ifrån kravspecifikationen. Resultatet visade på ett teoretiskt fungerande snabbfästeskoncept som uppfyller målet och stora delar av den uppsatta kravspecifikationen. Slutkonceptet tillåter enkel anpassningsbarhet mellan maskiner och hindrar inte deras rörelsemönster. Nedre delen av snabbfästet är standardiserad och redskapsfästet är fullständigt standardiserat. Interface mellan snabbfästet och redskapsfästet är standardiserat. Hydrauliklösningen på snabbfästet är innesluten och låsningen sker på undersidan av snabbfästet vilket bidrar till hög felsäkerhet vid låsning, låg klämrisk och liten dammbildning vid hydraulik och elektricitets-inkopplingen. Redskapsfästet är utrustad med en skyddslucka som automatiskt öppnas vid inkoppling. Undersökningen har visat att det är möjligt att skapa en snabbfästesstandard för hjullastare i den angivna viktklassen men det kommer med en del krav. Slutkonceptet kräver att ett fåtal länkar hos de uppmätta maskinerna byts ut.

  • 22.
    Höglund, Sebastian
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Staaf, Carl
    Mid Sweden University.
    Utveckling av metod för finkalibriga ballistiska tester2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 23.
    Jawa, Mohammed
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Konstruktionsförslag för lastanordning till likbil2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med arbetet var att analysera marknaden för att sedan ta fram ett konstruktionsunderlag för en lastanordning i en likbil för företaget Ortman Specialanpassningar. Konceptet skall innefatta en konstruktion med bland annat funktionalitetskrav som skall underlätta förflyttning och förvaring av en kista i en likbil. Projektet inleddes med en idé tillsammans med en förstudie som sedan gick över till en designprocess som är en utvecklingsprocess som ger användaren flera olika metoder under flera faser. Projektet gick igenom flera olika stadie där projektet planerades, kontexten utforskades, koncept utformning och till slut gick över till ett konstruktionsunderlags-stadie. Därefter analyserades konstruktionsunderlaget och simulerades genom en belastningsanalys med hjälp av SolidWorks. Material valdes, där dessa val baserades på projektets kravspecifikation. Slutligen renderades konstruktionsunderlaget i programmet KeyShot.

  • 24.
    Jawad, Mohammed
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Konstruktionsförslag för lastanordning till likbil2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 25.
    Jiang, Yan
    et al.
    Stockholm University, Stockholm.
    Deiana, Luca
    Stockholm University, Stockholm.
    Zhang, Keihang
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lin, Shuangzheng
    Stockholm University, Stockholm.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Total Asymmetric Synthesis of Quinine, Quinidine, and Analogues via Catalytic Enantioselective Cascade Transformations2019In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 35, p. 6016-6023Article in journal (Refereed)
    Abstract [en]

    A catalytic asymmetric strategy for the total synthesis of quinuclidine natural products, which includes the completed enantioselective synthesis of the classical targets quinine and quinidine is disclosed. It is based on catalytic asymmetric cascade transformations, which paves the road for the synthesis of both enantiomers of the crucial C4 stereocenter with high enantioselectivity (up to 99 % ee) in one pot. Next, developing a route to all possible stereoisomers of a common early-stage intermediate sets the stage for the total synthesis of different enantiomers or epimers of quinine, quinidine and analogues with high selectivity. 

  • 26.
    Johansson, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Produktutveckling av tillbehör för bandsågverk: Utveckling av tillbehör för minskad förslitning av sågblad2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Rapporten presenterar ett utvecklingsprojekt utfört för Logosol AB i Härnösand. Projektet innefattar produktutveckling av ett tillbehör för bandsågverk B1001, där syftet var att förlänga livslängden på bandsågverkets såg-blad. Betydande del av förslitningen på sågbladen förekommer genom att föroreningar i stockarnas bark dras med genom stocken av sågbladet, detta medför sedan ökad förslitning och kortare livslängd på bandsågverkets såg-blad. Utveckling av ett tillbehör för att motverka detta grundades i att skapa en konstruktion som tar bort

  • 27.
    Johansson, Filip
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Säkerhet- och kvalitetsanalys av rulltrappor: En undersökning av trappsteg med avseende på hållfasthet2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 28.
    Jonsson, Bengt-Gunnar
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Svensson, Johan
    SLU, Umeå.
    Mikusiński, Grzegorz
    SLU, Riddarhyttan/Skinnskatteberg.
    Manton, Michael
    Vytautas Magnus University, Akademija, Kaunas District, Lithuania.
    Angelstam, Per
    SLU, Skinnskatteberg.
    European Union's last intact forest landscapes are at a value chain crossroad between multiple use and intensified wood production2019In: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 10, no 7, article id 564Article in journal (Refereed)
    Abstract [en]

    Research Highlights: The European Union's last large intact forest landscapes along the Scandinavian Mountain range in Sweden offer unique opportunities for conservation of biodiversity, ecological integrity and resilience. However, these forests are at a crossroad between intensified wood production aimed at bio-economy, and rural development based on multi-functional forest landscapes for future-oriented forest value chains. Background and Objectives:We (1) estimate the area of near-natural forests potentially remaining for forest harvesting and wood production, or as green infrastructure for biodiversity conservation and human well-being in rural areas, (2) review how forest and conservation policies have so far succeeded to reduce the loss of mountain forests, and (3) discuss what economic, socio-cultural and ecological values that are at stake, as well as different governance and management solutions.Materials andMethods: First, we estimated the remaining amount of intact mountain forests using (1) the Swedish National Forest Inventory, (2) protected area statistics, (3) forest harvest permit applications and actually harvested forests, (4) remote sensing wall-to-wall data on forests not subject to clear-felling since the mid-1950s, (5) mapping of productive and non-productive forestland, and (6) estimates of mean annual final felling rate. Second, we review policy documents related to the emergence of land use regulation in north Sweden, including the mountain forest border, and illustrate this with an actual case that has had significant policy implementation importance. Results: There is a clear difference between the proportions of formally protected productive forestland above the mountain forest border (52.5%) and north Sweden in general (6.3%). A total of 300,000 ha of previously not clear-felled mountain forest outside protected areas remain, which can support novel value chains that are not achievable elsewhere. Conclusions: The mountain forests in Sweden provide unique conservation values in the European Union. Since the beginning of the 1990s, policy regulations have been successful in limiting forest harvesting. Currently, however, mountain forests are a battle ground regarding intensification of forest use, including logging of forests that have never been subject to clear-felling systems vs. nature conservation and wilderness as a base for rural development. The ability of mountain municipalities to encourage sustainable rural forest landscapes must be strengthened. 

  • 29.
    Koli, Rohit R.
    et al.
    Shivaji Univ, Kolhapur, Maharashtra, India; Shivaji Univ, Kolhapur, Maharashtra, India.
    Phadatare, Manisha R.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. DY Patil Univ, Kolhapur, Maharashtra, India.
    Sinha, Bhavesh B.
    Univ Mumbai, Mumbai, Maharashtra, India.
    Sakate, Deepak M.
    Shivaji Univ, Kolhapur, Maharashtra, India.
    Ghule, Anil V.
    Shivaji Univ, Kolhapur, Maharashtra, India.
    Ghodake, Gajanan S.
    Dongguk Univ Seoul, Goyang Si, Gyeonggi Do, India.
    Deshpande, Nishad G.
    Shivaji Univ, Dept Phys, Kolhapur, Maharashtra, India.
    Fulari, Vijay J.
    Shivaji Univ, Kolhapur, Maharashtra, India.
    Gram bean extract-mediated synthesis of Fe3O4 nanoparticles for tuning the magneto-structural properties that influence the hyperthermia performance2019In: Journal of the Taiwan Institute of Chemical Engineers / Elsevier, ISSN 1876-1070, E-ISSN 1876-1089, Vol. 95, p. 357-368Article in journal (Refereed)
    Abstract [en]

    A green synthesis of biocompatible magnetite (Fe3O4) nanoparticles (MNPs) using a combination of urea (U) and gram-bean extract (GBE, Cicer arietinum L.) is reported. The particle size of similar to 13 nm and highly stable magnetite phase is observed for GBE-U mediated MNPs. On the other hand, the MNPs synthesized using either U or GBE shows larger particle size and uneven size distribution. Interestingly, the sample with particle size similar to 13 nm shows optimum heat generation capacity (measured in specific absorption rate, i.e., SAR) near to the therapeutic temperature (43 degrees C) with least-variance. To investigate the influence of various factors such as variation in MNPs weight concentration (W-t), applied alternating magnetic field (AMF), saturation magnetization (M-s), magnetization rate (R-m), etc. on SAR, a multiple linear regression model (MLRM) is used. The study reveals a positive correlation of SAR with R-m, and AMF values while the negative correlation with M-s and W-t. Ultimately, the present green synthesis is the affordable approach for preparing stable and tiny MNPs. Moreover, MLRM is found to be a useful theoretical tool for understanding the influence of MNPs on hyperthermia performance. 

  • 30.
    Larsson, Rebecka
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Optimering av interna leveranser i maskinlinjen – anodhängare och maskiner2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 31.
    Molina-Lopez, F.
    et al.
    Stanford University, Stanford, CA United States; KU Leuven, Leuven, Belgium.
    Gao, T. Z.
    Stanford University, Stanford, CA United States.
    Kraft, U.
    Stanford University, Stanford, CA United States; University of Cambridge, Cambridge, United Kingdom.
    Zhu, C.
    Stanford University, Stanford, CA United States.
    Öhlund, Thomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Stanford University, Stanford, CA United States.
    Pfattner, R.
    Stanford University, Stanford, CA United States; Institute of Materials Science of Barcelona (ICMAB-CISC), Bellaterra, Spain.
    Feig, V. R.
    Stanford University, Stanford, CA United States.
    Kim, Y.
    Stanford University, Stanford, CA United States.
    Wang, S.
    Stanford University, Stanford, CA United States; University of Chicago, Chicago, IL United States.
    Yun, Y.
    Samsung Advanced Institute of Technology, Suwon, South Korea.
    Bao, Z.
    Stanford University, Stanford, CA United States.
    Inkjet-printed stretchable and low voltage synaptic transistor array2019In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, no 1, article id 2676Article in journal (Refereed)
    Abstract [en]

    Wearable and skin electronics benefit from mechanically soft and stretchable materials to conform to curved and dynamic surfaces, thereby enabling seamless integration with the human body. However, such materials are challenging to process using traditional microelectronics techniques. Here, stretchable transistor arrays are patterned exclusively from solution by inkjet printing of polymers and carbon nanotubes. The additive, non-contact and maskless nature of inkjet printing provides a simple, inexpensive and scalable route for stacking and patterning these chemically-sensitive materials over large areas. The transistors, which are stable at ambient conditions, display mobilities as high as 30 cm2 V−1 s−1 and currents per channel width of 0.2 mA cm−1 at operation voltages as low as 1 V, owing to the ionic character of their printed gate dielectric. Furthermore, these transistors with double-layer capacitive dielectric can mimic the synaptic behavior of neurons, making them interesting for conformal brain-machine interfaces and other wearable bioelectronics. 

  • 32.
    Morian, Viktor
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Fästanordningskoncept för skridskoslipmaskin2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 33.
    Nilsson, Oscar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Ergonomisk utformning av punktsvets2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 34.
    Niskane, Tomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Testrigg: Utveckling av laborationsutrustning2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 35.
    Niskanen, Ilpo
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. University of Oulu, Oulu, Finland.
    Forsberg, Viviane
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. KTH.
    Zakrisson, Daniel
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Reza, Salim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    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.
    Fedorov, Igor
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Suopajärvi, Terhi
    University of Oulu, Oulu, Finland.
    Liimatainen, Henrikki
    University of Oulu, Oulu, Finland.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Determination of nanoparticle size using Rayleigh approximation and Mie theory2019In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 201, no 29, p. 222-229Article in journal (Refereed)
    Abstract [en]

    Accurate determination of the size of nanoparticles has an important role in many different scientific and industrial purposes, such as in material, medical and environment sciences, colloidal chemistry and astrophysics. We describe an effective optical method to determine the size of nanoparticles by analysis of transmission and scattering of visible spectral range data from a designed UV-Vis multi-spectrophotometer. The size of the nanoparticles was calculated from the extinction cross section of the particles using Rayleigh approximation and Mie theory. We validated the method using polystyrene nanospheres, cellulose nanofibrils, and cellulose nanocrystals. A good agreement was achieved through graphical analysis between measured extinction cross section values and theoretical Rayleigh approximation and Mie theory predictions for the sizes of polystyrene nanospheres at wavelength range 450 - 750 nm. Provided that Rayleigh approximation's forward scattering (FS)/back scattering (BS) ratio was smaller than 1.3 and Mie theory's FS/BS ratio was smaller than 1.8. A good fit for the hydrodynamic diameter of nanocellulose was achieved using the Mie theory and Rayleigh approximation. However, due to the high aspect ratio of nanocellulose, the obtained results do not directly reflect the actual cross-sectional diameters of the nanocellulose. Overall, the method is a fast, relatively easy, and simple technique to determine the size of a particle by a spectrophotometer. Consequently, the method can be utilized for example in production and quality control purposes as well as for research and development applications.

  • 36.
    Nordvall, Robbin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Optimering av mekaniska egenskaper för bärverk2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 37.
    Nyström, Alexander
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Free-form compensation of cemented carbide inserts: A new method for systematic compensation2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The manufacturing of cemented carbide tools is a continuous process that keeps developing along with new technologies and possibilities. To increase efficiency when developing these tools, every step in the process needs to be optimized and kept up to date in order to remain relevant in a competitive market.

    This report presents a new method for free-form compensation with the use of newly developed simulations. The simulation creates a deformed model that accurately identifies most of the deformations that occur during the press and sinter of an insert. With this data, it becomes possible to perform compensations before any tool is produced. This will allow a higher efficiency when developing new tools and in turn, reduce the material waste.

    The developed method is based on point cloud transformation which can be reconstructed to allow an automated compensation process. By using the simulated data and nominal model, the difference between every surface point can be calculated and compensated accordingly using MATLAB.

    In this project, a completely new insert has been designed with extreme geometrical shapes to evaluate the method. To verify this, two prototypes have been created. One reference insert with the usual 18% compensation and an insert based on the new compensation method. By comparing the two, it is visible that the method effectively reduces the tolerances on the first compensation loop. There is, however, much work left to implement this method in today's manufacturing. In order to use the method, several steps need to be tested further. The goal of this method is to completely remove the need for several compensation loops and prevent manual compensation practice.

     

  • 38.
    Olsen, Martin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Nanomechanics – Quantum Size Effects, Contacts, and Triboelectricity2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nanomechanics is different from the mechanics that we experience in everyday life. At the nano-scale, typically defined as 1 to 100 nanometers, some phenomena are of crucial importance, while the same phenomena can be completely neglected on a larger scale. For example, the feet of a gekko are covered by nanocontacts that yield such high adhesion forces that the animal can run up on walls and even on the ceiling. At small enough distances, matter and energy become discrete, and the description of the phenomena occurring at this scale requires quantum mechanics. However, at room temperature the transitions between quantized energy levels may be concealed by the thermal vibrations of the system. As two surfaces approach each other and come into contact, electrostatic forces and van der Waals forces may cause redistribution of matter at the nano level. One effect that may occur upon contact between two surfaces is the triboelectric effect, in which charge is transferred from one surface to the other.This effect can be used to generate electricity in triboelectric nanogenerators (TENGs), where two surfaces are repeatedly brought in and out of contact, and where the charge transfer is turned into electrical energy.

    This thesis concerns nanomechanics addressing whether quantum mechanics play a role in elastic deformation, as well as various mechanical aspects of nanocontacts including electric charging. The objectives are to contribute to the understanding when quantum effects are of importance at the nanolevel, increase the fundamental understanding of the mechanisms responsible for triboelectric phenomena and apply the triboelectric effect to a wind harvesting device.

    For more insight into whether quantum effects are of importance in nanomechanics, we use a one dimensional jellium model and the standard beam theory allowing the spring constant of an oscillating nanowire cantilever to be calculated. As the nanowire bends, more electron states fit in its cross section, giving rise to an amplitude dependent resonance frequency of the nanowire oscillations.

    Furthermore, a model for electric field induced surface diffusion of adatoms was developed. The model takes electrostatic forces and van der Waals forces into account as a voltage is applied between a scanning tunneling microscope tip and a sample. The calculated force on the adatoms at the surface of the sample, which is stemming from the inhomogeneous electric field and the dipole moment of the adatoms, is relatively small, but due to thermal vibrations adatoms diffuse and form mounds at the sample.

    When bringing two different materials into contact, the difference in triboelectric potentials between the materials results in electric charging. To increase the understanding of triboelectricity, a two-level Schottky model, assuming ion transfer, was developed to describe the temperature dependence of the triboelectric effect for a TENG. The two levels correspond to the binding energy for ions on the two surfaces that are brought into contact, where the difference in binding energy enters the Boltzmanndistribution. The model describes the decreasing triboelectric effect in TENG:s with increasing temperature as described in the literature, and results in a separation energy, which is of the right order of magnitude for physically adsorbed atoms.

    It was recently demonstrated that TENGs can convert wind energy into electrical energy. Here, a TENG based on a plastic film fluttering between two copper electrodes was constructed. It was found that the frequency of the the fluttering film increases linearly with the wind speed. TENG:s designed in this way generate electricity already at low wind speed, and we therefore expect such TENG:s to be useful both as generators and speed sensors in the future.

    While quantum mechanics is of importance in a limited number of nanomechanical systems, nanocontacts have a broader meaning, and are crucial for the understanding of triboelectric phenomena. We anticipate that the findings in this thesis will contribute to a better understanding of nanomechanics, in particular the mechanism of triboelectricity.

  • 39.
    Olsen, Martin
    et al.
    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.
    Örtegren, Jonas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andersson, Henrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Yang, Ya
    CAS Center for excellence in Nanoscience, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Science.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Frequency and voltage response of a wind-driven fluttering triboelectric nanogenerator2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, no 1, article id 5543Article in journal (Refereed)
    Abstract [en]

    Triboelectric nanogenerators (TENG:s) are used as efficient energy transducers in energy harvesting converting mechanical energy into electrical energy. Wind is an abundant source of mechanical energy but how should a good triboelectric wind harvester be designed? We have built and studied a TENG driven by air flow in a table-top sized wind tunnel. Our TENG constitutes of a plastic film of size10 cm × 2 cm which is fluttering between two copper electrodes generating enough power to light up a battery of LED:s. We measured the voltage and frequency of fluttering at different wind speeds from zero up to 8 m/s for three electrode distances 6 mm, 10 mm and 14 mm. We found that the frequency increases linearly with the wind speed with a cutoff at some low speed. Power was generated already at 1.6 m/s. We seem to be able to explain the observed frequency dependence on wind speed by assuming excitation of the film into different harmonics in response to von Kármán vortices. We also find that the voltage increase linearly with frequency. We anticipate that TENG:s of this design could be useful both as generators and speed sensors because they work at low air speeds.

  • 40.
    Phadatare, Manisha R.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Deemed Univ, Maharashtra, India.
    Patil, Rohan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Blomquist, Nicklas
    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.
    Örtegren, Jonas
    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.
    Meshram, Jagruti
    Deemed Univ, Maharashtra, India.
    Hernández, Guiomar
    Uppsala Univ, Uppsala.
    Brandell, Daniel
    Uppsala Univ, Uppsala.
    Leifer, Klaus
    Uppsala Univ, Uppsala.
    Sathyanath, Sharath Kumar Manjeshwar
    Uppsala Univ, Uppsala.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Silicon-Nanographite Aerogel-Based Anodes for High Performance Lithium Ion Batteries2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 14621Article in journal (Refereed)
    Abstract [en]

    To increase the energy storage density of lithium-ion batteries, silicon anodes have been explored due to their high capacity. One of the main challenges for silicon anodes are large volume variations during the lithiation processes. Recently, several high-performance schemes have been demonstrated with increased life cycles utilizing nanomaterials such as nanoparticles, nanowires, and thin films. However, a method that allows the large-scale production of silicon anodes remains to be demonstrated. Herein, we address this question by suggesting new scalable nanomaterial-based anodes. Si nanoparticles were grown on nanographite flakes by aerogel fabrication route from Si powder and nanographite mixture using polyvinyl alcohol (PVA). This silicon-nanographite aerogel electrode has stable specific capacity even at high current rates and exhibit good cyclic stability. The specific capacity is 455 mAh g−1 for 200th cycles with a coulombic efficiency of 97% at a current density 100 mA g−1.

  • 41.
    Rastabi, Shahrzad Arshadi
    et al.
    Tarbiat Modares Univ, Tehran, Iran.
    Mamoory, Rasoul Sarraf
    Tarbiat Modares Univ, Tehran, Iran.
    Dabir, Fatemeh
    Niroo Res Inst, Tehran, Iran.
    Blomquist, Nicklas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Phadatare, Manisha R.
    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.
    Synthesis of NiMoO4/3D-rGO Nanocomposite in Alkaline Environments for Supercapacitor Electrodes2019In: Crystals, ISSN 2073-4352, Vol. 9, no 1, article id 31Article in journal (Refereed)
    Abstract [en]

    Although Graphene oxide (GO)-based materials is known as a favorable candidate for supercapacitors, its conductivity needs to be increased. Therefore, this study aimed to investigate the performance of GO-based supercapicitor with new methods. In this work, an ammonia solution has been used to remove the oxygen functional groups of GO. In addition, a facile precipitation method was performed to synthesis a NiMoO4/3D-rGO electrode with purpose of using synergistic effects of rGO conductivity properties as well as NiMoO4 pseudocapacitive behavior. The phase structure, chemical bands and morphology of the synthesized powders were investigated by X-ray diffraction (XRD), Raman spectroscopy, and field emission secondary electron microscopy (FE-SEM). The electrochemical results showed that the NiMoO4/3D-rGO(II) electrode, where ammonia has been used during the synthesis, has a capacitive performance of 932 Fg(-1). This is higher capacitance than NiMoO4/3D-rGO(I) without using ammonia. Furthermore, the NiMoO4/3D-rGO(II) electrode exhibited a power density of up to 17.5 kW kg(-1) and an energy density of 32.36 Wh kg(-1). These results showed that ammonia addition has increased the conductivity of rGO sheets, and thus it can be suggested as a new technique to improve the capacitance.

  • 42.
    Razaz, Ghadir
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Problems in the Aluminium DC Casting Process Associated with Melt Treatment Operations2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The quality of DC cast Al alloys is highly dependent on melt batch composition and impurity level in the molten alloy. The chemical composition and cleanliness of a melt is controlled through the melt treatment operations, carried out while the melt is still in the furnace before casting starts. The present work has studied some of these operations and associated problems such as slow dissolution of alloying elements, non-reproducibility in chemical composition analysis and inclusions.

     The results of the dissolution of the alloy elements Mn and Fe showed different behaviors.  For Mn three intermediate phases were involved, all of which exhibited a smooth interface between Mn and the liquid. These three phases were identified as the γ2, Al11Mn4, and µ phases, which grow slowly towards the dissolving Mn particles. The results from the Fe dissolution revealed that only one phase dominates the process, Al5Fe2, which penetrates the Fe particles with an irregular interface.

    The interaction between Mn and Ti additions to AA3003 alloys and consequences for the solidification and precipitation behavior was investigated. The study could map the limits for formation of an earlier unknown AlMnTi phase, which formed large particles, detrimental for subsequent rolling operations.

    Different sampling procedures for chemical composition analysis were studied, and a novel approach was proposed. A mould with an insulated periphery provided one-dimensional solidification, which gave compositions close to nominal.

     Inclusion distributions along as-cast billets were studied as a function of different holding times, and thus different grades of sedimentation. Holding times longer than 30 minutes did not show any improvements.  It was also shown that if melt remaining in the furnace at end of casting is less than about 3000 kg, the sedimented inclusions are stirred into the bulk again, and can enter into the end of the billet.

    The impact on hot tearing susceptibility of different Cu and Fe contents for AA3000 alloys was studied. Cu contents in a range from 0.3 to 1.2 wt%  significantly increase the hot tearing tendency, which was attributed to bad feeding at end of solidification. Decreasing of the Fe content below 0.2 wt%, gives a strong cracking tendency, owing to decreased precipitations of the Al6(Mn,Fe) phase, which contributes to early bridging and thus reinforcement between grains.

  • 43.
    Razaz, Ghadir
    et al.
    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.
    Hot tearing susceptibility of AA3000 aluminum alloy containing Cu, Ti, and Zr2019In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 50A, no 8, p. 3842-3854Article in journal (Refereed)
    Abstract [en]

    Severe hot tearing has been observed during DC casting of modified AA3000 alloys with additions of Cu, Ti, and Zr, although these alloys are regarded as rather easy to cast. Extensive studies have been performed on both synthetic and industrial AA2000, AA6000, and AA7000 alloys, but less data are available for AA3000 alloys. This work was thus initiated to investigate the hot tearing susceptibility of AA3000 alloys with varying alloy element content using constrained rod casting molds. The results showed that the Cu and Fe content have a major impact on hot tearing resistance, while the effects of Zr and Ti are minor. Cu in a range from 0.3 to 1.2 wt pct significantly increased the hot tearing tendency. This is due to the existence of high eutectic fractions at low temperatures, as well as porosity formation associated with bad feeding at the end of solidification. A strong cracking tendency was observed below an Fe content 0.2 wt pct owing to decreased precipitation of the Al6(Mn, Fe) phase. It was found that primary Al6(Mn, Fe) phases lead to early bridging between the grains, which reinforces the alloy during the vulnerable temperature range for hot tearing. Zr and Ti additions weakly enhanced or reduced hot tearing severity, respectively.

  • 44.
    Razaz, Ghadir
    et al.
    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.
    On the dissolution Process of Manganese and Iron in Molten Aluminum2019In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 50, no 4, p. 1873-1887Article in journal (Refereed)
    Abstract [en]

    The dissolution of Mn and Fe in liquid Al presents a challenge due to their high melting points and low diffusivity. A literature review reveals that the existing knowledge of the processes involved in the dissolution of both Fe and Mn in liquid Al is rather ambiguous. Thus, this work aimed to obtain more detailed insights into the dissolution behavior of Mn and Fe in various Al melts. The results of the Mn dissolution tests showed that three intermediate phases were involved in the dissolution process, all of which exhibited a smooth interface between Mn and the liquid. These three phases were identified as the γ2, Al11Mn4, and µ phases which grow slowly, penetrating the Mn particles. The results of the Fe dissolution tests showed that in pure Al, the Al5Fe2 phase dominates the dissolution process and penetrates the Fe particles. The addition of Ti into the molten Al alters the intermetallic compound formation by replacing Al5Fe2 by Al2Fe. The addition of Si significantly inhibited the Fe dissolution kinetics. A theoretical approach based on Ficks’ law was used to explain the experimentally obtained Mn and Fe dissolution rates. It showed that the surface area and shape of the additives significantly affected the dissolution processes.

  • 45.
    Sandström, Jennie
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Bernes, Claes
    Stockholm Environment Institute, Stockholm.
    Junninen, Kaisa
    Metsähallitus Parks & Wildlife Finland, Joensuu, Finland; University of Eastern Finland, Joensuu, Finland.
    Lõhmus, Asko
    Tartu University, Tartu, Estonia.
    Macdonald, Ellen
    University of Alberta, Edmonton, AB, Canada.
    Müller, Jörg
    Bavarian Forest National Park, Grafenau, Germany.
    Jonsson, Bengt-Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Impacts of dead-wood manipulation on the biodiversity of temperate and boreal forests - A systematic review2019In: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 56, no 7, p. 1770-1781Article in journal (Other academic)
    Abstract [en]

    Dead wood (DW) provides critical habitat for thousands of species in forests, but its amount, quality and diversity have been heavily reduced by forestry. Therefore, interventions aiming to increase DW might be necessary to support its associated biodiversity, even in protected forests, which may be former production forests. Our aim was to synthesize the current state of knowledge drawn from replicated experimental studies into solid quantitative evidence of the effects of DW manipulation on forest biodiversity, with a focus on protected forests.

    We conducted a full systematic review of effects of DW manipulation on forest biodiversity in boreal and temperate regions. We included three intervention types: creation of DW from live trees at the site, addition of DW from outside the site and prescribed burning. Outcomes included abundance and species richness of saproxylic insects, ground insects, wood-inhabiting fungi, lichens, reptiles and cavity-nesting birds. In total, we included 91 studies, 37 of which were used in meta-analyses. Although meta-analysis outcomes were heterogeneous, they showed that increasing the amount of DW (“DW enrichment”) has positive effects on the abundance and richness of saproxylic insects and fungi. The positive effect on saproxylic pest insect abundance tended to be less than that on saproxylic insects in general. No significant effects were found for ground insects or cavity-nesting birds.

    Although reviewed studies were mainly short term, our results support that management that increases DW amounts has the potential to increase the abundance of DW-dependent species and, in most cases, also their species richness. Studies of burning showed positive effects on the abundance of saproxylic insects similar to those of other interventions, even though burning on average resulted in a smaller enrichment of DW amounts.

    Policy implications. The findings of the review suggest that manipulating dead wood (DW) can be an effective part of conservation management to support biodiversity in protected areas. The findings also indicate that the diversity of DW types is important, a mix of DW qualities should be favoured. Burning seems to be an effective method to increase biodiversity but to benefit cavity-nesting birds, snag losses need to be minimized.

  • 46.
    Skytt, Torbjörn
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Ecotechnology and Suistainable Building Engineering.
    Nors Nielsen, Soeren
    Aalborg University, Copenhagen, Denmark.
    Jonsson, Bengt-Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Global warming potential and absolute global temperature change potentialfrom carbon dioxide and methane fluxes as indicators of regionalsustainability – A case study of Jämtland, Sweden2020In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 110, article id 105831Article in journal (Refereed)
    Abstract [en]

    This study presents a regional model showing the balance of carbon dioxide and methane fluxes in the Swedish county Jämtland, applying a Global Warming Potential 20-year time horizon (GWP20) to meet the Paris agreement horizon and regional policy goals. The results clearly show the necessity to take both anthropogenic and non-anthropogenic emissions into consideration in analyses to be able to make proper priorities in future action strategies. The total annual impact from Jämtland calculated as carbon dioxide equivalents (CO2eq) is an uptake of 2.4 Mton (19 ton per capita). Jämtland shows large annual uptakes in forests (12.7 Mton CO2), but also large emissions of methane (80 kton corresponding to 6.7 Mton CO2eq), mainly from lakes, mires and ruminants. Anthropogenic carbon Greenhous gas emissions are dominated by transportation, working machines and consumption (mainly imported indirect emissions).

    As a complement to GWP also the Absolute Global Temperature Change Potential (AGTP) as degree K response, is presented per sector and total for Jämtland County, for yearly emissions (as a pulse) and continuous emissions over 200 years. A yearly pulse from Jämtland gives a temperature response of about 0 K after 10 years and about −4 μK (cooling effect) after about 50 years). Using both GWP and AGTP as indicators improves the possibilities to find ways how to optimize regional climate policies to reduce global warming until a specific year.

    Strategies and action plans should be developed focusing on the following:

    - Reduced regional transportation and consumption activity.

    - Increased (prioritized) use of renewable fuels for working machines in forestry and agriculture, as well as for heavy trucks.

    - Evaluate the potential to reduce emissions of methane from wetlands and mires.

    - Increase/optimize carbon dioxide assimilation in forests.

  • 47.
    Svensson, Johan
    et al.
    Swedish University of Agricultural Sciences, Umeå.
    Andersson, Jon
    Sweco Environment AB, Umeå.
    Sandström, Per
    Swedish University of Agricultural Sciences, Umeå.
    Mikusiński, Grzegorz
    Swedish University of Agricultural Sciences, Riddarhyttan; Swedish University of Agricultural Sciences, Skinnskatteberg.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Swedish University of Agricultural Sciences, Umeå.
    Landscape trajectory of natural boreal forest loss as an impediment to green infrastructure2019In: Conservation Biology, ISSN 0888-8892, E-ISSN 1523-1739, Vol. 33, no 1, p. 152-163Article in journal (Refereed)
    Abstract [en]

    Loss of natural forests by forest clearcutting has been identified as a critical conservation challenge worldwide. This study addressed forest fragmentation and loss in the context of the establishment of a functional green infrastructure as a spatiotemporally connected landscape-scale network of habitats enhancing biodiversity, favorable conservation status, and ecosystem services. Through retrospective analysis of satellite images, we assessed a 50- to 60-year spatiotemporal clearcutting impact trajectory on natural and near-natural boreal forests across a sizable and representative region from the Gulf of Bothnia to the Scandinavian Mountain Range in northern Fennoscandia. This period broadly covers the whole forest clearcutting period; thus, our approach and results can be applied to comprehensive impact assessment of industrial forest management. The entire study region covers close to 46,000 km2 of forest-dominated landscape in a late phase of transition from a natural or near-natural to a land-use modified state. We found a substantial loss of intact forest, in particular of large, contiguous areas, a spatial polarization of remaining forest on regional scale where the inland has been more severely affected than the mountain and coastal zones, and a pronounced impact on interior forest core areas. Salient results were a decrease in area of the largest intact forest patch from 225,853 to 68,714 ha in the mountain zone and from 257,715 to 38,668 ha in the foothills zone, a decrease from 75% to 38% intact forest in the inland zones, a decrease in largest patch core area (assessed by considering 100-m patch edge disturbance) from 6114 to 351 ha in the coastal zone, and a geographic imbalance in protected forest with an evident predominance in the mountain zone. These results demonstrate profound disturbance of configuration of the natural forest landscape and disrupted connectivity, which challenges the establishment of functional green infrastructure. Our approach supports the identification of forests for expanded protection and conservation-oriented forest landscape restoration. 

  • 48.
    Svensson, Lina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Tofferi, Liisa
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Utvärdering av materialval i bärhjul: En studie innehållande simuleringar2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Arbetet utfördes åt uppdragsgivaren BAE Systems Hägglunds AB som har en bandvagn vars maximala vikt har uppnåtts. Syftet med arbetet var att öka bandvagnens bärhjuls bärförmåga och få det att tåla högre temperaturer än tidigare. Målet med arbetet var att se vilka förändringar på bärhjulet som ökade dess hållfasthet samt vilka förändringar som inte ökade dess hållfasthet. Bärhjulet skulle vara av en termoplast. Ett bärhjul erhölls av uppdragsgivaren för att kunna bestämma materialegenskaperna hos det befintliga bärhjulet. Fem koncept togs fram och undersöktes. Koncepten var en insatt eker av aluminium, materialbyte till komposit av UHMWPE-fiber, materialbyte till tvärbunden UHMWPE, materialbyte till glasfiberförstärkt HDPE samt en insatt eker av glasfiberförstärkt HDPE. De fem koncepten och det befintliga bärhjulet genomgick en numerisk analys med hjälp av simuleringar i SolidWorks där de skulle klara fyra lastfall. Lastfallen var statisk last, cyklisk last, radiell last och axiell last. Resultatet av den numeriska analysen för det befintliga bärhjulet erhölls för att jämföra de fem koncepten med. Materialdata för att kunna modellera materialen till de olika koncepten i SolidWorks erhölls från publicerade resultat, detta på grund av att arbetets omfattning på tio veckor ansågs för kort för att hinna göra egna prov på alla de material som undersöktes. Tre av fem koncept klarade alla lastfall förutom ett. Inget av koncepten klarade den axiella lasten. Alla koncepten visade på bättre resultat än det befintliga bärhjulet i den numeriska analysen. Det enda konceptet som inte visade på bättre hållfasthet var det konceptet med en eker av aluminium i då bärhjulet sprack inifrån på grund av ekern.

  • 49.
    Vilhelmsson, Björn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Nytänkande trygghetslarm2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 50.
    Zhang, Keihang
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Deiana, Luca
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Svensson Grape, Erik
    Stockholm University, Stockholm.
    Inge, A. Ken
    Stockholm University, Stockholm.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Catalytic Enantioselective Synthesis of Bicyclic Lactam N,S-Acetals in One Pot by Cascade Transformations2019In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 2019, no 29, p. 4649-4657Article in journal (Refereed)
    Abstract [en]

    A versatile strategy for the enantioselective synthesis of bicyclic lactam N,S-acetals by one-pot cascade transformations is disclosed. The transformation of readily available substrates is promoted by chiral amines and creates bicyclic or tricyclic lactam N,S-acetals with high chemo- and stereoselectivity (up to > 99.5:0.5 dr and > 99 % ee) in one-pot operations.

12 1 - 50 of 53
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