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  • 1.
    Alimohammadzadeh, Rana
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Osong, Sinke H.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Abbaszad Rafi, Abdolrahim
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Dahlström, Christina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Cordova, Armando
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Cellulosic Materials: Sustainable Surface Engineering of Lignocellulose and Cellulose by Synergistic Combination of Metal-Free Catalysis and Polyelectrolyte Complexes2019Ingår i: Global Challenges, ISSN 2056-6646, Vol. 3, nr 7, artikel-id 1970071Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In article number 1900018 by Armando Cordova and co‐workers, the novel combination of metal‐free catalysis and renewable polyelectrolyte complexes leads to synergistic surface engineering of lignocellulose and cellulose fibers derived from wood. This sustainable strategy allows for improvement and introduction of important properties such as strength (up to 100% in Z‐strength), water resistance, and fluorescence to the renewable fibers and cellulosic materials under eco‐friendly conditions.

  • 2.
    Alimohammadzadeh, Rana
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Osong, Sinke H.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Abbaszad Rafi, Abdolrahim
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Dahlström, Christina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Cordova, Armando
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sustainable Surface Engineering of Lignocellulose and Cellulose by Synergistic Combination of Metal‐Free Catalysis and Polyelectrolyte Complexes2019Ingår i: Global Challenges, E-ISSN 2056-6646, Vol. 3, artikel-id 1900018Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A sustainable strategy for synergistic surface engineering of lignocellulose and cellulose fibers derived from wood by synergistic combination of metal‐free catalysis and renewable polyelectrolyte (PE) complexes is disclosed. The strategy allows for improvement and introduction of important properties such as strength, water resistance, and fluorescence to the renewable fibers and cellulosic materials. For example, the “green” surface engineering significantly increases the strength properties (up to 100% in Z‐strength) of chemi‐thermomechanical pulp (CTMP) and bleached sulphite pulp (BSP)‐derived sheets. Next, performing an organocatalytic silylation with a nontoxic organic acid makes the corresponding lignocellulose and cellulose sheets hydrophobic. A selective color modification of polysaccharides is developed by combining metal‐free catalysis and thiol‐ene click chemistry. Next, fluorescent PE complexes based on cationic starch (CS) and carboxymethylcellulose (CMC) are prepared and used for modification of CTMP or BSP in the presence of a metal‐free catalyst. Laser‐scanning confocal microscopy reveals that the PE‐strength additive is evenly distributed on the CTMP and heterogeneously on the BSP. The fluorescent CS distribution on the CTMP follows the lignin distribution of the lignocellulosic fibers.

  • 3.
    Alves, Luis
    et al.
    Univ Coimbra, Coimbra, Portugal.
    Medronho, Bruno
    Univ Algarve, Faro, Portugal.
    Filipe, Alexandra
    Univ Algarve, Faro, Portugal.
    Antunes, Filipe E.
    Univ Coimbra, Coimbra, Portugal.
    Lindman, Björn
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik. Univ Coimbra, Coimbra, Portugal; Lund Univ, Lund.
    Topgaard, Daniel
    Lund Univ, Lund.
    Davidovich, Irina
    Technion Israel Inst Technol, Haifa, Israel.
    Talmon, Yeshayahu
    Technion Israel Inst Technol, Haifa, Israel.
    New Insights on the Role of Urea on the Dissolution and Thermally-Induced Gelation of Cellulose in Aqueous Alkali2018Ingår i: GELS, ISSN 2310-2861, Vol. 4, nr 4, artikel-id 87Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The gelation of cellulose in alkali solutions is quite relevant, but still a poorly understood process. Moreover, the role of certain additives, such as urea, is not consensual among the community. Therefore, in this work, an unusual set of characterization methods for cellulose solutions, such as cryo-transmission electronic microscopy (cryo-TEM), polarization transfer solid-state nuclear magnetic resonance (PTssNMR) and diffusion wave spectroscopy (DWS) were employed to study the role of urea on the dissolution and gelation processes of cellulose in aqueous alkali. Cryo-TEM reveals that the addition of urea generally reduces the presence of undissolved cellulose fibrils in solution. These results are consistent with PTssNMR data, which show the reduction and in some cases the absence of crystalline portions of cellulose in solution, suggesting a pronounced positive effect of the urea on the dissolution efficiency of cellulose. Both conventional mechanical macrorheology and microrheology (DWS) indicate a significant delay of gelation induced by urea, being absent until ca. 60 degrees C for a system containing 5wt % cellulose, while a system without urea gels at a lower temperature. For higher cellulose concentrations, the samples containing urea form gels even at room temperature. It is argued that since urea facilitates cellulose dissolution, the high entanglement of the cellulose chains in solution (above the critical concentration, C*) results in a strong three-dimensional network.

  • 4.
    Bergström, Per
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Hossain, Shakhawath
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Uesaka, Tetsu
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Scaling Behaviour of Strength of 3D-, Semi-flexible-, Cross-linked Fibre Network2019Ingår i: International Journal of Solids and Structures, ISSN 0020-7683, E-ISSN 1879-2146, Vol. 166, nr July 2019, s. 68-74Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Anisotropic, semi-flexible, cross-linked, random fibre networks are ubiquitous both in nature and in a wide variety of industrial materials. Modelling mechanical properties of such networks have been done extensively in terms of criticality, mechanical stability, and scaling of network stiffnesses with structural parameters, such as density. However, strength of the network has received much less attention. In this work we have constructed 3D-planar fibre networks where fibres are, more or less, oriented in the in-plane direction, and we have investigated the scaling of network strength with density. Instead of modelling fibres as 1D element (e.g., a beam element with stretching, bending and/or shear stiffnesses), we have treated fibres as a 3D-entity by considering the features like twisting stiffness, transverse stiffness, and finite cross-link (or bond) strength in different deformation modes. We have reconfirmed the previous results of elastic modulus in the literature that, with increasing density, the network modulus indeed undergoes a transition from bending-dominated deformation to stretching-dominated with continuously varying scaling exponent. Network strength, on the other hand, scales with density with a constant exponent, i.e., showing no obvious transition phenomena. Using material parameters for wood fibres, we have found that the predicted results for stiffness and strength agree very well with experimental data of fibre networks of varying densities reported in the literature.

  • 5.
    Bergström, Robin
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Reducering av utsläpp till luft: Optimering av SCA Ortvikens drift och underhållsarbete2019Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    SCA Ortvikens energiavdelning har fem stycken fastbränslepannor som försörjer interna förbrukare med processånga. Bränslet är i huvudsak bark, biologiskt slam och pelletspulver. SCA är ålagda att registrera utsläpp till luft och redovisa detta enligt de i verksamhetstillståndet villkorsbelagda utsläppen samt för kväveoxid-deklaration och för handel om utsläppsrätter för CO2. Förutom verksamhetstillståndet innefattas SCA Ortviken dessutom av förordningen 2013:252 Stora förbränningsanläggningar. För att redovisa detta används miljöredovisningssystemet ”MRS” från Entric AB. Drift-och underhåll saknar i nulägen en övergripande bild över MRS vilket skulle underlätta deras arbete för att säkerställa funktion på ingående signaler och därmed minska risken för mätbortfall vilket kan förebygga höga utsläpp under produktionen i framtiden. I detta arbete har, genom flödesscheman för de mest relevanta signaler och mätvärden vad gäller utsläpp som är kopplade till MRS, kunna underlätta för processoperatörer och underhållsorganisationen att säkerställa mätfunktionen. Arbetet har dessutom, genom analys av historiska data över driften, lett till förslag på åtgärder för att minska bildandet av olika utsläpp. Arbetet har visat att det finns många enkla åtgärder som kan göras för att minska utsläppen på redan befintligt installerad teknik på pannorna, men även gett förslag på annat teknik, och hur denna kan appliceras. Arbetet har också visat på brister i den nuvarande dokumentation-och signalhanteringen i avseende att göra mätvärden synliga i processystem andra än MRS.

  • 6.
    Blomquist, Nicklas
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Alimadadi, Majid
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hummelgård, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Dahlström, Christina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Olsen, Martin
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Olin, Håkan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Effects of Geometry on Large-scale Tube-shear Exfoliation of Multilayer Graphene and Nanographite in Water2019Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, nr 1, artikel-id 8966Artikel i tidskrift (Refereegranskat)
    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.

  • 7.
    Blomquist, Nicklas
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Koppolu, R.
    Dahlström, Christina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Toivakka, M.
    Olin, Håkan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Influence of Substrate in Slot-die Coating of Nanographite/Nanocelluose Electrodes for SupercapacitorsManuskript (preprint) (Övrigt vetenskapligt)
  • 8.
    Bohman, Björn
    et al.
    University of Western Australia, Crawley, WA, Australia; Swedish University of Agricultural Sciences, Alnarp.
    Weinstein, Alyssa M.
    Australian National University, Acton, ACT, Australia.
    Mozuraitis, Raimondas
    Stockholm University, Stockholm.
    Flematti, Gavin R.
    University of Western Australia, Crawley, WA, Australia.
    Borg-Karlson, Anna-Karin
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Identification of (Z)-8-Heptadecene and n-Pentadecane as Electrophysiologically Active Compounds in Ophrys insectifera and Its Argogorytes Pollinator2020Ingår i: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 21, nr 2Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sexually deceptive orchids typically depend on specific insect species for pollination, which are lured by sex pheromone mimicry. European Ophrys orchids often exploit specific species of wasps or bees with carboxylic acid derivatives. Here, we identify the specific semiochemicals present in O. insectifera, and in females of one of its pollinator species, Argogorytes fargeii. Headspace volatile samples and solvent extracts were analysed by GC-MS and semiochemicals were structurally elucidated by microderivatisation experiments and synthesis. (Z)-8-Heptadecene and n-pentadecane were confirmed as present in both O. insectifera and A. fargeii female extracts, with both compounds being found to be electrophysiologically active to pollinators. The identified semiochemicals were compared with previously identified Ophrys pollinator attractants, such as (Z)-9 and (Z)-12-C27-C29 alkenes in O. sphegodes and (Z)-9-octadecenal, octadecanal, ethyl linoleate and ethyl oleate in O. speculum, to provide further insights into the biosynthesis of semiochemicals in this genus. We propose that all these currently identified Ophrys semiochemicals can be formed biosynthetically from the same activated carboxylic acid precursors, after a sequence of elongation and decarbonylation reactions in O. sphegodes and O. speculum, while in O. insectifera, possibly by decarbonylation without preceding elongation.

  • 9.
    Cordova, Armando
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Afewerki, Samson
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Alimohammadzadeh, Rana
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sanhueza, Italo
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Tai, Cheuk-Wai
    Stockholm University, Stockholm.
    Osong, Sinke H.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Engstrand, Per
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Ibrahem, Ismail
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    A sustainable strategy for production and functionalization of nanocelluloses2019Ingår i: Pure and Applied Chemistry, ISSN 0033-4545, E-ISSN 1365-3075, Vol. 91, nr 5, s. 865-874Artikel i tidskrift (Refereegranskat)
    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.

  • 10.
    Costa, Carolina
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Medronho, Bruno
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik. University of Algarve, Faro, Portugal.
    Filipe, Alexandra
    University of Algarve, Faro, Portugal.
    Mira, Isabel
    RISE, Stockholm.
    Lindman, Björn
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Edlund, Håkan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Norgren, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Emulsion formation and stabilization by biomolecules: The leading role of cellulose2019Ingår i: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 11, nr 10, artikel-id 1570Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Emulsion stabilization by native cellulose has been mainly hampered because of its insolubility in water. Chemical modification is normally needed to obtain water-soluble cellulose derivatives. These modified celluloses have been widely used for a range of applications by the food, cosmetic, pharmaceutic, paint and construction industries. In most cases, the modified celluloses are used as rheology modifiers (thickeners) or as emulsifying agents. In the last decade, the structural features of cellulose have been revisited, with particular focus on its structural anisotropy (amphiphilicity) and the molecular interactions leading to its resistance to dissolution. The amphiphilic behavior of native cellulose is evidenced by its capacity to adsorb at the interface between oil and aqueous solvent solutions, thus being capable of stabilizing emulsions. In this overview, the fundamentals of emulsion formation and stabilization by biomolecules are briefly revisited before different aspects around the emerging role of cellulose as emulsion stabilizer are addressed in detail. Particular focus is given to systems stabilized by native cellulose, either molecularly-dissolved or not (Pickering-like effect). 

  • 11.
    Costa, Carolina
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Mira, Isabel
    RISE, Stockholm.
    Benjamins, Jan-Willem
    RISE, Stockholm.
    Lindman, Björn
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Edlund, Håkan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Norgren, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Interfacial activity and emulsion stabilization of dissolved cellulose2019Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 292, artikel-id 111325Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Some aspects of the interfacial behavior of cellulose dissolved in an aqueous solvent were investigated. Cellulose was found to significantly decrease the interfacial tension (IFT) between paraffin oil and 85 wt% phosphoric acid aqueous solutions. This decrease was similar in magnitude to that displayed by non-ionic cellulose derivatives. Cellulose's interfacial activity indicated a significant amphiphilic character and that the interfacial activity of cellulose derivatives is not only related to the derivatization but inherent in the cellulose backbone. This finding suggests that cellulose would have the ability of stabilizing dispersions, like oil-in-water emulsions in a similar way as a large number of cellulose derivatives. In its molecularly dissolved state, cellulose proved to be able to stabilize emulsions of paraffin in the polar solvent on a short-term. However, long-term stability against drop-coalescence was possible to achieve by a slight change in the amphiphilicity of cellulose, effected by a slight increase in pH. These emulsions exhibited excellent stability against coalescence/oiling-off over a period of one year. Ageing of the cellulose solution before emulsification (resulting in molecular weight reduction) was found to favour the creation of smaller droplets. 

  • 12.
    Dahlström, Christina
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    López Durán, V.
    KTH, Stockholm.
    Keene, S. T.
    Stanford University, Stanford, CA, United States.
    Salleo, A.
    Stanford University, Stanford, CA, United States.
    Norgren, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Wågberg, L.
    KTH, Stockholm.
    Ion conductivity through TEMPO-mediated oxidated and periodate oxidated cellulose membranes2020Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 233, artikel-id 115829Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cellulose in different forms is increasingly used due to sustainability aspects. Even though cellulose itself is an isolating material, it might affect ion transport in electronic applications. This effect is important to understand for instance in the design of cellulose-based supercapacitors. To test the ion conductivity through membranes made from cellulose nanofibril (CNF) materials, different electrolytes chosen with respect to the Hofmeister series were studied. The CNF samples were oxidised to three different surface charge levels via 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), and a second batch was further cross-linked by periodate oxidation to increase wet strength and stability. The outcome showed that the CNF pre-treatment and choice of electrolyte are both crucial to the ion conductivity through the membranes. Significant specific ion effects were observed for the TEMPO-oxidised CNF. Periodate oxidated CNF showed low ion conductivity for all electrolytes tested due to an inhibited swelling caused by the crosslinking reaction. © 2020 Elsevier Ltd

  • 13.
    Eivazihollagh, Alireza
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Löf, Ludwig
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Lindman, Björn
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Norgren, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Edlund, Håkan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Vesicle-templated all-cellulose nanocapsules2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Polymeric multilayers capsules constructed using the layer-by-layer (LbL) technique are interesting candidates for the purposes of storage, encapsulation and release in a wide range of biomedical applications. In the current study, cellulose-based nanocapsules were produced via the LbL technique. In this procedure, alternating deposition of the two biocompatible polymers anionic cellulose, carboxymethylcellulose (CMC), and cationic cellulose, quaternized hydroxyethylcellulose ethoxylate (QHECE), on a cationic vesicular template made of didodecyldimethylammonium bromide (DDAB), was performed. The obtained nanocapsules, were characterized by dynamic light scattering (DLS), ⇣ potential measurements, and field-emission scanning electron microscopy (FE-SEM). DLS measurements revealed that the size of the spheres is about hundreds of nanometer with polydispersity index (PDI) values between 0.2 and 0.3, indicating a relatively homogeneous size distribution. In addition, FESEM characterization also indicated the shape and size of obtained material. The surface charge analysis of the nanocapsules by ⇣ potential measurements indicated the presence of electrostatically stabilized nanoparticles. The values of diameter, PDI and surface charge for cationic vesicles coated by CMC were 204 nm, 0.26 and –38 mV, respectively. After deposition of QHECE, the diameter, PDI, and surface charge were about 265 nm, 0.36 and +32.5 mV, respectively. Figure 1 shows FE-SEM images of cellulose nanoparticles fabricated via LbL deposition of polyelectrolyte layers. As seen in the microscopy images, the shape of the core-shell particles are not fully spherical which could be due to drying e↵ects of the sample before FE-SEM characterization. The construction of cellulose nanocontainers by using an alternating deposition of oppositely charged biobased polyelectrolytes on vesicles o↵ers several advantages such as simplicity, reproducibility, biocompatibility, low-cost, mild reaction conditions, and high controllability over the thickness and composition of the shell.

  • 14.
    Eivazihollagh, Alireza
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Svanedal, Ida
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Edlund, Håkan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Norgren, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    On chelating surfactants: Molecular perspectives and application prospects2019Ingår i: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 278, s. 688-705Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Chelating agents, molecules that very strongly coordinates certain metal ions, are used industrially as well as in consumer products to minimize disturbances and increase performance of reactions and applications. The widely used sequestering agents, nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) belong to this branch of readily water-soluble compounds. When these chemical structures also have hydrophobic parts, they are prone to adsorb at air-water interfaces and to self-assemble. Such bifunctional molecules can be called chelating surfactants and will have more extended utilization prospects than common chelating agents or ordinary ionic surfactants. The present review attempts to highlight the fundamental behavior of chelating surfactants in solution and at interfaces, and their very specific interactions with metal ions. Methods to recover chelating surfactants from metal chelates are also described. Moreover, utilization of chelating surfactants in applications for metal removal in environmental engineering and mineral processing, as well as for metal control in the fields of biology, chemistry and physics, is exemplified and discussed.

  • 15.
    El Miri, Nassima
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Norgren, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Cellulose nanocrystals: a new route towards strong nature-based and barrier materials2019Ingår i: EPNOE2019 Book of Abstracts, 2019, s. 97-Konferensbidrag (Refereegranskat)
    Abstract [en]

    An increasing consciousness toward the reduction of the environmental impact producedby plastic waste, has driven research and industry to focus on using biodegradable materials. Among those biodegradable materials, polysaccharides are regarded to have great potential in packaging applications, because of their outstanding performance with biocompatibility, biodegradability, and good processability. Naturally, most of the polysaccharides do not exhibit desired barrier properties, due to their hydrophilic nature, which hinder their application in packaging field. The incorporation of reinforcing structures such as cellulosenanocrystals (CNCs) in these polysaccharides is promising approach to produce new materials for food packaging application with specific properties and high performances. CNCs have been mostly used as reinforcing phase in matrices for a variety of materials, and thus given to their outstanding properties such as exceptional mechanical strength, biocompatibility, broadchemical modification, and large surface area. The aim of this study is the development of biodegradable films based on polysaccharides and CNCs from different ressources using agreen method such as the evaporation casting method and focusing on the final produced material properties related to food packaging applications (mechanical properties, thermal properties, antibacterial properties, optical transparency and resistance to water vapor and oxygen transmission).

  • 16.
    Engstrand, Per
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Ferritsius, Rita
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Rundlöf, Mats
    Capisco AB.
    Paulsson, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Decrease in strengthalong a process line for SC paper2019Ingår i: Fundamental Mechanical Pulp Research Seminar, FMPRS2019, Norrköping, SwedenArranged by Mid Sweden University in cooperatrion with Holmen AB, Valmet AB, AF AB and Treesearch., 2019Konferensbidrag (Refereegranskat)
  • 17.
    Ferritsius, Olof
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Ferritsius, Rita
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Ferritsius, Johanna
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Rundlöf, Mats
    Capisco.
    Heterogeneity2019Ingår i: Heterogeneity, 2019Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Heterogeneity may be a most proper word to describe paper and board. Wood, the raw material to produce mechanical pulps, is almost as heterogeneous a material as the products. Looking in a microscope at a mechanical pulp it is obvious that it consists of a huge amount of small particles, which vary very much in several aspects: length, curl, width, wall thickness, fibrillation etc. In spite of that, we (scientists, mill employees, suppliers, consultants, researchers) commonly describe a pulp in terms of collective properties such as averages of fibre dimensions, hand sheet properties, dewatering ability etc. In other words: we describe mechanical pulp as a continuum. This may be more common than we believe. A review of the variables used in the more than 5,000 graphs in the preprints of the 23 International Mechanical Pulping Conferences (IMPC) between 1973 and 2018 showed that 97% of the variables described mechanical pulp as a continuum. Hence, only 3% of the variables reflected the heterogeneous nature of mechanical pulps.   Many authors point out the benefits of describing the character of a material by as few and as independent properties as possible. In 1957, Steenberg stated: “Any valuable theory must be supposed to include a number of independent factors”. However, within the mechanical pulping area it is common practise to evaluate the character of pulp with respect to a wide range of more or less correlated measured pulp and fibre properties. In the review of the last 23 IMPCs we found that more than 96% of the variables examined in the articles where of that kind. In our efforts to describe a mechanical pulp with respect to its highly heterogeneous nature we have among others been inspired by Forgacs who worked with independent common factors in order to characterize mechanical pulps. He presented a paper in 1963 where he states that at least two independent factors are needed to describe a mechanical pulp. They reflect shape and length of the particles. Also Strand has inspired us with his work in the 80’s where he used factor analysis on a huge database to derive two independent common factors reflecting “bonding” (Factor 1) and “fibre length” (Factor 2). Examining a few independent common factors instead of several conventionally measured properties, which are more or less correlated, makes it easier to get an overview of the status of the processed material. Therefore, it is a little surprising that independent common factors constitute only 4% of the variables presented at the IMPCs since 1973. Strands approach was tested in a long-term evaluation in two mills. It was possible to produce a paper product more uniform in quality, compared to common practise. However, none of the above-mentioned independent factors reflects the heterogeneity of the pulp.   Paper and pulp makers commonly agree that, within certain limits, uniformity is the most important characteristic of both the pulp and the paper. If we know how to perform uniformly, we may also be able to move into other operating areas (or volumes) in a controlled way. However, there is no common agreement on how to define "uniformity". Papermakers are still to a great extent specifying their demands on the pulp in terms of dewatering ability and average length-weighted fibre length although the correlation to product quality is vague and weak and varies over time. Almost since the advent of mechanical pulping processes, the operators have for process control had readings of dewatering ability of a pad consisting of billions of particles expressed as mL of water and average length-weighted fibre length of the pulp, which are far from being independent factors. Variations in any of these two properties may depend on variations in a combination of several more underlying factors. Therefore, it is hard to know what actions the operators should take to avoid running off spec. So far, the main development in the concept with dewatering and length to assist the operators have been firstly, to get time trends of these variables on a DCS screen instead of on a piece of paper in the control room, and secondly to get the readings more frequently with on-line analysers. During the same period, there have been an immense development of refiner concepts, fractionation, process design, modelling, use of raw material, fibre characterization, and new products.   By putting more attention to reality and describing mechanical pulp as a heterogeneous material, which the mechanical pulps truly are, we hope to be able to get a more profound understanding how wood particles are developed along the process all the way to product. We also hope to give the operators in the mechanical pulping plant a more realistic description of the material they are supposed to deliver to the paper and board makers in order to facilitate their possibilities to produce a more uniform product quality at minimum cost.  The aim of our presentation is to share some of our insights and reflections how to describe the heterogeneous nature of mechanical pulps to the mill operators.

    We have applied factor analysis on particle level based on measurements in an optical analyser of fibre diameter, fibre wall thickness, fibre length, and fibre fibrillation. Examples will be presented of how the raw material and the process have set characteristic fingerprints in terms of the distribution of an independent common bonding factor on particle level. It is fascinating to see how much that may be hidden behind averages, c.f. Rosling et al. (2018) who warn against comparing averages, which often obstruct a more profound understanding of a subject.   In our presentation, we intend also to discuss how a description of the heterogeneity of the material may be used to get measures of energy efficiency of the process, separation efficiency of fractionation equipment, and how to link fibre characteristics to properties of products. Some reflections will also be shared on what we think is further required to get a more realistic description of the heterogeneous material we call mechanical pulp. Reference:  Rosling H., Rosling Rönnlund A., Rosling O., (2018), ”Factfulness”, Natur & Kultur,  ISBN 978-91-27-14994-6

  • 18.
    Fiskari, Juha
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Kilpeläinen, Petri
    Natural Resource Institute Finland LUKE.
    Evaluation of the potential of Acacia Mangium and Eucalyptus pellita as feedstock for biorefinery2019Ingår i: Proceedings of the 20th ISWFPC, Tokyo, Japan, 2019, s. P-44-Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This laboratory research was undertaken to gain a better understanding of Acacia mangium and Eucalyptus pellita and their feasibility as feedstock in acid sulfite pulping. The plantation-grown hardwood chip samples were obtained from Sabah, Malaysia. The wood samples were analyzed for carbohydrates, lignin and extractives. The cooking experiments were carried out in 2L autoclaves with temperatures of 130°C and 140°C, with varied chemical charges, after which the resulting pulp samples were characterized for kappa number and fiber quality. The results revealed that a cooking temperature of 140°C was needed to reach kappa numbers below 30, but this also resulted in much reduced fiber length and higher fines content than 130°C, probably due to the intensified acid hydrolysis. To reach kappa numbers below 20, even more severe cooking conditions would be needed. This kind of pulp and the resulting lignin may be well used as intermediate products in biorefineries.

  • 19.
    Forsberg, Viviane
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap. KTH, Stockholm; Wallenberg Wood Science Centre, Stockholm.
    Mašlík, Jan
    Tomas Bata University in Zlín, Zlín, Czech Republic.
    Norgren, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Electronic performance of printed PEDOT:PSS lines correlated to the physical and chemical properties of coated inkjet papers2019Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, nr 41, s. 23925-23938Artikel i tidskrift (Refereegranskat)
    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.

  • 20.
    Hossain, Shakhawath
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik. Uppsala university, Uppsala.
    Bergström, Per
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Uesaka, Tetsu
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Uniaxial Compression of Three-Dimensional Entangled Fibre Networks: Impacts of Contact Interactions2019Ingår i: Modelling and Simulation in Materials Science and Engineering, ISSN 0965-0393, E-ISSN 1361-651X, Vol. 27, nr 1, artikel-id 015006Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    This paper concerns uniaxial compression of anisotropic fibre network, as typically seen in the end use of nonwoven and textile fibre assemblies. The constitutive relationship and deformation mechanism have been investigated by using a bead-model to represent the complex structures of the constituent fibres and the fibre networks. The compression stress shows a power-law dependency on the density with a threshold density for both experimental and numerical fibre networks. Unlike the widely studied tri-axial compression of the initially isotropic network, it was found that the contact interaction between the fibres, especially the fibre-fibre contact stiffness (or the transverse compression properties of fibres), has a large impact on all the constitutive parameters. In particular, the exponent values computed based on the softer contact stiffnesses agreed very well with the experimental values reported in the literature. The internal deformation mechanism was similar to the earlier studies that at low compression, the deformation is dominated by the low-energy-mode deformations (i.e. bending and shear), whereas at higher compression, the difference appears: the compression of fibre-fibre contacts, instead of the deformation in the fibre axial direction, takes over.

  • 21.
    Jama, Mohamed Ali
    et al.
    Aalto University, Finland.
    Zhao, Wenli
    Tianjin University of Science and Technology, China.
    Ahmad, Waqar
    Aalto University, Finland.
    Buffo, Antonio
    Politecnico di Torino, Torino, Italy.
    Alopaeus, Ville
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik. Aalto University, Finland.
    Analytical time-stepping solution of the discretized population balance equation2020Ingår i: Computers and Chemical Engineering, ISSN 0098-1354, E-ISSN 1873-4375, Vol. 135, artikel-id 106741Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The prediction of the particle-size distribution (PSD) of the particulate systems in chemical engineering is very important in a variety of different contexts, such as parameter identification, troubleshooting, process control, design, product quality, production economics etc. The time evolution of the PSD can be evaluated by means of the population balance equation (PBE), which is a complex integro-differential equation, whose solution in practical cases always requires sophisticated numerical methods that may be computationally tedious. In this work, we propose a novel technique that tackles this issue by using an analytical time-stepping procedure (ATS) to resolve the PSD time dependency. The ATS is an explicit time integrator, taking advantage of the linear or almost linear time dependency of the discretized population balance equation. Thus, linear approximation of the source term is a precondition for the ATS simulations. The presented technique is compared with a standard variable step time integrator (MATLAB ODE15s stiff solver), for practical examples e.g. emulsion, aging cellulose process, cooling crystallization, reactive dissolution, and liquid-liquid extraction. The results show that this advancing in time procedure is accurate for all tested practical examples, allowing reproducing the same results given by standard time integrators in a fraction of the computational time. 

  • 22.
    Joelsson, Tove
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik. MoRe Research Örnsköldsvik AB.
    High strength paper from high yield pulps by means of hot-pressing2020Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Sammanfattning

    Högutbytesmassa (HYP), d.v.s. SGW, TMP eller CTMP, används normalt i tryckpapper (News, SC och LWC) eller i mittskikt i kartong dvs i produkter som har höga krav på tryckbarhet och körbarhet i snabba tryckpressar eller för att bidra till hög bulk i kartong så att man därmed kan minimera förbrukningen av massa för att nå en viss arkstyvhet. Dragstyrka som funktion av densitet är väsentligt högre för HYP jämfört med kemiska massor som sulfat- och sulfitmassor. Däremot används främst kemiska massor i förpackningsmaterial som kräver mycket hög dragstryka, där man samtidigt tillåter att papperets densitet får vara hög. Genom att utnyttja mjukningsegenskaperna hos högutbytesmassors ligninrika fibrer genom varmpressningsteknik kan man väsentligt öka arkdensitet och därigenom styrka till i nivå med kemiska massors. Vidare visas att man tack vara närvaro av höga halter lignin kan nå väsentligt högre våtstyrka jämfört med kemisk massa utan tillsats av styrkehöjande kemikalier. Studien fokuserar på mjukgörning av styva och ligninrika fibrer vid varmpressning vid temperaturnivåer väsentligt över mjukningstemperaturen (Tg) för lignin av HYP-baserat papper med tillräckligt hög fukthalt. Varmpressning ökar arkens densitet, vilket ökar kontaktytan mellan fibrerna i pappersstrukturen. Den höga pressnings-temperaturen kan sägas inducera ett visköst flöde av lignin, vilket då ökar möjligheten att få starkare för fiber-fiber-bindning. Man kan dels tänka sig att kovalenta bindningar erhålls via kondensationsreaktioner och dels att man kan erhålla interdiffusion mellan ligninet i fiberväggarna då de kommer tillräckligt nära varandra vid varmpressningen. Forskningen visar också att varmpressning högst väsentligt förbättrar egenskaper i form av torr- och våtstyrka samt hydrofobicitet för både HYP-baserat och ligninrikt kraftpapper. Den första delen av studien visar effekten av varmpressning på styrke-egenskaper hos pappersark baserade på CTMP, HT-CTMP, TMP, NSSC, SCPal och NBSK. Den andra delen inkluderar en studie om hur och i vilken utsträckning olika mängder av kvarvarande lignin i massa bidrar till pappersarkens torrstyrka och våtstyrka vid varmpressning som funktion av ökande temperatur. För att demonstrera detta tillverkades oblekt kraftmassa till olika ligninhalter i pilotskala. I alla experiment i del ett och två i avhandlingen tillverkades laboratorieark med ytvikten 150 g/m2 och torrhalten 50% i en Rapid Köthen (RK) arkformare varefter arken varmpressades i en cylinderpress vid temperaturer upp till 200°C och konstant högt tryck på cirka 7 MPa i ett pressnyp med uppehållstiden 1,5 s i pressnypet  vid maskinhastigheten 1 m/min. Den tredje delen i avhandlingen inkluderar en studie om optimering av variabler i en ny design av en dynamisk cylinderpress för varmpressteknik. Den nya designen baseras på tidigare forskning vid Mittuniversitetet kombinerat med nyckelkunskap om stålbandstekniker inom IPCO AB. Den nya pilotmaskinen är baserad på att ett stålbälte uppvärms med infraröd värme (IR) upp till 300°C, en linjelast upp till 15 kN/m i två pressnyp vardera, med variabel presstid 23-240 ms i pressnypet beroende av maskinhastigheter upp till 5 m/min. Experimenten i del tre i avhandlingen baserades på RK-pappersark tillverkade av HT-CTMP med ytvikten 100 g/m2 och torrhalten ca 63%. Resultaten bekräftar att varmpressande HYP-baserade pappersark möjliggör permanent densifiering genom mjukning av lignin, vilket ger en mycket hög torr dragstyrka och en anmärkningsvärd förbättring av våt dragstyrka jämfört med blekt kraftmassa utan att våtstyrkemedel behöver användas. Ett dragindex på 75 kNm/kg, kompressionsstyrkeindex (SCT) på 45 kNm/kg och våtstyrkeindex på 16 kNm/kg erhölls vilket kan jämföras med motsvarande värden för pappersarken från blekt kraftmassa på 85 kNm/kg, 35 kNm/kg respektive 5 kNm/kg, alla med samma densitet efter varmpressning vid 200°C. Lövvedsbaserad NSSC nådde det högsta dragstyrkeindexet på hela 92 kNm/kg. Studien med de oblekta kraftmassorna visade att lignininnehållet hade en signifikant effekt på både torr- och våtstyrkeindex. Kraftmassorna uppvisade ett linjärt samband mellan våtstyrka och lignininnehåll. Ökningen i ligninhalten från 0% till 12% förbättrade dragindexet med 20% och SCT med 35% och gav en mycket signifikant ökning i våtstyrkeindex från 3 till 23 kNm/kg efter varmpressningen. Alla ligninrika pappersprover uppvisar god våtstyrkestabilitet under minst 24 timmar och en förbättrad ythydrofobicitet genom ökning av presstrycktemperaturen och lignininnehållet.

    Optimering av den nya stålbandsbaserade cylinderpressen visade att högt pressnyptryck och två pressnyp hade stor effekt på densitet och styrka. Emedan hög temperatur, långt över Tg för lignin, och lång presstid var viktigare för att nå hög våtstyrka. Det högsta värdet på våtstyrkeindex, 27 kNm/kg, uppnåddes när presstemperaturen var 290°C, pressnyptrycket cirka 8 MPa, presstiden i pressnypet 40 ms och tiden i kontakt med stålbältet 23,5 sek. Det noterades också att ingen delaminering inträffade i dessa tester.

    För att erhålla både hög torr- och våtstyrka är det viktigt med högt lignininnehåll, hög temperatur, högt nyptryck och tillräckligt lång presstid.

  • 23.
    Joelsson, Tove
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Pettersson, Gunilla
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Norgren, Sven
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Svedberg, Anna
    MoRe Research Örnsköldsvik AB.
    Höglund, Hans
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Engstrand, Per
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    High strength paper from high yield pulps by means of hot-pressing2020Ingår i: Artikel i tidskrift (Refereegranskat)
  • 24.
    Joelsson, Tove
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Pettersson, Gunilla
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Norgren, Sven
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Svedberg, Anna
    MoRe Research Örnsköldsvik AB.
    Höglund, Hans
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Engstrand, Per
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Improved paper wet-strength by increasing lignin content and hot-pressing temperature2020Ingår i: Artikel i tidskrift (Refereegranskat)
  • 25.
    Joelsson, Tove
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Pettersson, Gunilla
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Norgren, Sven
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Svedberg, Anna
    MoRe Research Örnsköldsvik AB.
    Höglund, Hans
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Engstrand, Per
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Unique steel belt technology for hot-pressing of wood-containing papersManuskript (preprint) (Övrigt vetenskapligt)
  • 26.
    Liu, H.
    et al.
    Huazhong University of Science and Technology, Wuhan, China.
    Qu, L.
    Huazhong University of Science and Technology, Wuhan, China.
    Chen, Y.
    Huazhong University of Science and Technology, Wuhan, China.
    Zhang, Wennan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Yang, H.
    Huazhong University of Science and Technology, Wuhan, China.
    Wang, X.
    Huazhong University of Science and Technology, Wuhan, China.
    Chen, H.
    Huazhong University of Science and Technology, Wuhan, China.
    Physicochemical characteristics and pyrolysis kinetics of hydrothermal carbon from natural Scenedesmus2019Ingår i: Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering, ISSN 1002-6819, Vol. 35, nr 14, s. 235-242Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to explore the utilization of natural microalgae, the natural Scenedesmus was selected to carry out hydrothermal carbonization experiments, and the characterization of its hydrochars was determined using Fourier transform infrared spectroscopy, X-ray diffraction analysis, X-ray fluorescence spectroscopy, environmental scanning electron microscopy and thermogravimetric analyzer. The results showed that the ash content of natural Scenedesmus was 44.66%, and the lipid and protein content of natural Scenedesmus were 1.4% and 15.1%, respectively. The natural microalgae ash components were mostly water-insoluble components. The main components included (Mg0.064Ca0.936CO3), SiO2, NaCl, Al2O3, CaSO4, Mg3S2O8(OH)2. After hydrothermal carbonization treatment, NaCl was dissolved in water, and the water-insoluble components were enriched in hydrochars. Compared with the natural Scenedesmus, the ash content of hydrochars increased, in the range from 57.41% to 71.47%. It was worth noting that the natural Scenedesmus and its derived hydrochars had no fixed carbon. With the increase of hydrothermal temperature, the hydrothermal carbon yield decreased from 47.29% (180℃) to 43.01% (240℃). This phenomenon was on account of the organic components in the natural Scenedesmus underwent hydrolysis, dehydration, decarboxylation, aromatization, condensation and polymerization. The carbon remaining ratio was the largest, the oxygen was the smallest, and the remaining ratios of carbon, hydrogen and oxygen decreased as the hydrothermal temperature increased. For HC-240, the removal rates of H and O were 69.88% and 93.88%, respectively, and the C remaining ration rate was 33.97%. The O/C molar ratio of hydrochars decreased from 1.45 to 0.28. Dehydration and decarboxylation were the main pathways in hydrothermal carbonization of the natural Scenedesmus, and the demethylation pathway was negligible. Oxygen was removed in the form of H2O and CO2. The degree of carbonization was enhanced and hydrochars had the potential to be applied to solid fuels. Since hydrochars contained a large amount of ash, its calorific value was in the range of 8.43-9.67 MJ/kg. Hence, the pretreatment of deashing was a necessary process. The hydrothermal carbonization treatment effectively improved the pore structure of hydrochars, and the absorption-desorption capacity of hydrochars was obviously enhanced. Compared with natural Scenedesmus (4.36 m2/g), the specific surface area of hydrochars was in the range of 28.7-35.26 m2/g. The natural Scenedesmus had a dense block-like without pores or pathways. However, the morphologies of hydrochars changed significantly. The fragmentation and porosity of hydrochars increased, which attributed to the release of volatile matter during hydrothermal carbonization process and chemical bond decomposition of feedstock. The thermogravimetric analysis experiments were carried out to reveal the pyrolysis characteristics of hydrochars. It was found that the weight loss peak at 300℃ gradually disappeared with the increased of hydrothermal temperature. This was owing to the degree of natural Scenedesmus increased and the volatile matter content decreased. When the hydrothermal temperature was higher than 220℃, the maximum weight loss rate peak moved to the high temperature zone. The pyrolysis kinetics results showed that the thermal stability of hydrochars increased with the increase of hydrothermal temperature. The hydrochars were more hydrophobic than that of the natural Scenedesmus. The research results provide a theoretical reference for the resource utilization of natural microalgae.

  • 27.
    Liu, Huihui
    et al.
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China.
    Chen, Yingquan
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China.
    Yang, Haiping
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China.
    Gentili, Francesco G.
    Swedish Univ Agr Sci, Umeå.
    Söderlind, Ulf
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Wang, Xianhua
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China.
    Zhang, Wennan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Chen, Hanping
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China.
    Hydrothermal carbonization of natural microalgae containing a high ash content2019Ingår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 249, s. 441-448Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The potential to convert natural microalgae (Scenedesmus) into solid fuels by hydrothermal carbonization (HTC) was evaluated. The deashing microalgae (DA) were obtained by acid-washing natural microalgae (NM) with HCl. The deashing efficiency was high from 44.66% for NM to 14.45% for DA. HTC carried out at temperature in the range from 180 to 260 degrees C with this two types feedstock (i.e. NM and DA). The results showed that DA-derived hydrochars had good physicochemical and fuel properties compared with that of NM-derived hydrochars. HTC process of DA was mainly based on polymerization, and the hydrolysis process was short. The hydrochars obtained from DA at 220 degrees C (HC-D220) had the highest value of 51.86% with a carbon content and fixed carbon content 1.15 and 1.33 times, respectively, greater than that of DA. The high heating value (HHV) of HC-D220 reached 26.64 MJ/kg which is equivalent to medium-high calorific coal. The thermogravimetric analysis (TG) demonstrated that the hydrochars derived from DA have good combustion properties with stable at high temperature zones. They can easily mix with coal or replace coal in combustion application. The results of this study revealed that natural microalgae can be utilized by hydrothermal carbonization to generate renewable fuel resources.

  • 28.
    Ljunggren, Joel
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    A screening study for antifungal activity of fractionated turpentine on wood-decaying fungi: in vitro, microcosm and field experiments.Manuskript (preprint) (Övrigt vetenskapligt)
  • 29.
    Ljunggren, Joel
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Some Approaches to Eco-Friendly Products from Natural Matrices2020Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Since the onset of the industrial and chemical revolution, humans have caused immense damages to the surrounding flora and fauna. Effective methods for wood protection measures proved to be toxic; fossil fuels contribute to global warming and pesticides can be detected in the air, water, and soil. It is abundantly clear that efforts to find eco-friendly products are needed, while simultaneously providing the necessary incentives for sustainable worldwide development. Using renewable resources play a critical role in this shift towards circular economies.

    Wood has long been used as a renewable resource in high demand, but its susceptibility to attack by wood-decaying fungi mean that most European woods need to be protected against these fungi before outdoor use. We showed that fractionating turpentine, a pulp and paper mill by-product, increased antifungal efficacy by concentrating bioactive oxygenated sesquiterpenes. Based on this result, recombinations of the fractions were shown to exhibit synergistic effects that enable a more efficient product utilisation. In addition, this approach enabled putative identifications of previously unknown Picea abies turpentine constituents present at low levels.

    For a carbon-neutral society, production of biofuels using oleaginous yeast to convert lignocellulosic biomass into fuel has been hailed as a next-generation source of bioenergy. However, lignocellulose biofuel production by microorganisms is not straightforward and one challenge is the formation of microbe-toxic monomers, such as vanillin, during lignin degradation. The oleaginous yeast Cystobasidium laryngis and other potential oil-producing yeasts were screened for their viability and vanillin biotransformation capabilities. To this end, a mass chromatographic peak extraction tool termed TMATE was developed. Vanillyl alcohol was found to be the main product following vanillin degradation.

    The detrimental health and ecological effects of pesticides highlight the urgency for alternative crop protection measures, such as biological insect control and semiochemicals. In this regard, we present an essential step towards understanding the varied chemical ecology of microbe-insect interactions. Our methodology and findings provide cues with high information value that can be used to develop well-informed and potentially sustainable pest management regimes by, for example, the push-pull methodology using live yeasts.

  • 30.
    Ljunggren, Joel
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Borrero-Echeverry, Felipe
    Swedish Univ Agr Sci, Alnarp; Corp Colombiana Invest Agr AGROSAVIA, Mosquera, Colombia.
    Chakraborty, Amrita
    Swedish Univ Agr Sci, Alnarp; Czech Univ Life Sci, Prague, Czech Republic.
    Lindblom, Tobias U. T.
    Swedish Univ Agr Sci, Alnarp/Ultuna.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Karlsson, Maria
    Swedish Univ Agr Sci, Alnarp.
    Witzgall, Peter
    Swedish Univ Agr Sci, Alnarp.
    Bengtsson, Marie
    Swedish Univ Agr Sci, Alnarp.
    Yeast Volatomes Differentially Affect Larval Feeding in an Insect Herbivore2019Ingår i: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 85, nr 21, artikel-id e01761-19Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Yeasts form mutualistic interactions with insects. Hallmarks of this interaction include provision of essential nutrients, while insects facilitate yeast dispersal and growth on plant substrates. A phylogenetically ancient chemical dialogue coordinates this interaction, where the vocabulary, the volatile chemicals that mediate the insect response, remains largely unknown. Here, we used gas chromatography-mass spectrometry, followed by hierarchical cluster and orthogonal partial least-squares discriminant analyses, to profile the volatomes of six Metschnikowia spp., Cryptococcus nemorosus, and brewer's yeast (Saccharomyces cerevisiae). The yeasts, which are all found in association with insects feeding on foliage or fruit, emit characteristic, species-specific volatile blends that reflect the phylogenetic context. Species specificity of these volatome profiles aligned with differential feeding of cotton leafworm (Spodoprera littoralis) larvae on these yeasts. Bioactivity correlates with yeast ecology; phylloplane species elicited a stronger response than fruit yeasts, and larval discrimination may provide a mechanism for establishment of insect-yeast associations. The yeast volatomes contained a suite of insect attractants known from plant and especially floral headspace, including (Z)-hexenyl acetate, ethyl (2E,4Z)-deca-2,4-dienoate (pear ester), (3E)-4,8-dimethylnona-1,3,7-triene (DMNT), linalool, alpha-terpineol, beta-myrcene, or (E,E)-alpha-farnesene. A wide overlap of yeast and plant volatiles, notably floral scents, further emphasizes the prominent role of yeasts in plant-microbe-insect relationships, including pollination. The knowledge of insect-yeast interactions can be readily brought to practical application, as live yeasts or yeast metabolites mediating insect attraction provide an ample tool-box for the development of sustainable insect management. IMPORTANCE Yeasts interface insect herbivores with their food plants. Communication depends on volatile metabolites, and decoding this chemical dialogue is key to understanding the ecology of insect-yeast interactions. This study explores the volatomes of eight yeast species which have been isolated from foliage, from flowers or fruit, and from plant-feeding insects. These yeasts each release a rich bouquet of volatile metabolites, including a suite of known insect attractants from plant and floral scent. This overlap underlines the phylogenetic dimension of insect-yeast associations, which according to the fossil record long predate the appearance of flowering plants. Volatome composition is characteristic for each species, aligns with yeast taxonomy, and is further reflected by a differential behavioral response of cotton leafworm larvae, which naturally feed on foliage of a wide spectrum of broad-leaved plants. Larval discrimination may establish and maintain associations with yeasts and is also a substrate for designing sustainable insect management techniques.

  • 31.
    Ljunggren, Joel
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Bylund, Dan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Jonsson, Bengt-Gunnar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Edman, Mattias
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Antifungal efficiency of individual compounds and evaluation of non-linear effects by recombining fractionated turpentine2020Ingår i: Microchemical journal (Print), ISSN 0026-265X, E-ISSN 1095-9149, Vol. 153, artikel-id 104325Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A combination between a reductive and a holistic assay was employed to investigate whole fraction, synergistic, antagonistic and individual compound efficacy of vacuumdistilled turpentine fractions against the economically important brown-rot fungus Coniophora puteana. The fungus was subjected to recombinations of turpentine fractions at a concentration of 1000 ppm. All combinations exhibited useful antifungal properties, but some antifungal mixtures showed a more pronounced effect than the expected level of inhibition. Synergistic effects by a two-fold factor and minor antagonistic effects were observed. Complete growth inhibition of C. puteana was observed by a fraction obtained after distilling 1 L turpentine at 111–177°C (0.5 mbar) as well as by mixing it with another fraction withdrawn at 70–79°C (0.5 mbar). Chemical compositions of distilled fractions were determined through GC–MS analysis and Orthogonal Partial Least Squares (OPLS) multivariate data analysis of GC–MS chromatograms was employed to zoom in on the most active compounds responsible for antifungal activity. Isomers of epicubenol, the hydrocarbon aromatic compound ar-himachalene and α-cadinol are suggested as effective antifungal compounds. In addition, a subsequent fractionation of the most effective fraction was performed with preparatory gas chromatography and subfractions showed similar or better efficacy than previously observed. Our work demonstrates the possibility to retain adequate synergistic antifungal efficiency and offers an opportunity to explore the effects of individual compounds originating from the same crude sample.

  • 32.
    Ljunggren, Joel
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Rönnander, J.
    Gävle högskola.
    Wright, S.A.I.
    Gävle högskola.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    TMATE: An R package for biotransformation product discovery and the application of biodegradation products in chemotypingManuskript (preprint) (Övrigt vetenskapligt)
  • 33.
    Magalhães, Solange
    et al.
    University of Coimbra, Coimbra, Portugal.
    Alves, Luís
    University of Coimbra, Coimbra, Portugal.
    Medronho, Bruno
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik. University of Algarve, Faro, Portugal.
    Fonseca, Ana C.
    University of Coimbra, Coimbra, Portugal.
    Romano, Anabela
    University of Coimbra, Coimbra, Portugal.
    Coelho, Jorge F.
    University of Coimbra, Coimbra, Portugal.
    Norgren, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Brief overview on bio-based adhesives and sealants2019Ingår i: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 11, nr 10, artikel-id 1685Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Adhesives and sealants (AS) are materials with excellent properties, versatility, and simple curing mechanisms, being widely used in different areas ranging from the construction to the medical sectors. Due to the fast-growing demand for petroleum-based products and the consequent negative environmental impact, there is an increasing need to develop novel and more sustainable sources to obtain raw materials (monomers). This reality is particularly relevant for AS industries, which are generally dependent on non-sustainable fossil raw materials. In this respect, biopolymers, such as cellulose, starch, lignin, or proteins, emerge as important alternatives. Nevertheless, substantial improvements and developments are still required in order to simplify the synthetic routes, as well as to improve the biopolymer stability and performance of these new bio-based AS formulations. This environmentally friendly strategy will hopefully lead to the future partial or even total replacement of non-renewable petroleum-based feedstock. In this brief overview, the general features of typical AS are reviewed and critically discussed regarding their drawbacks and advantages. Moreover, the challenges faced by novel and more ecological alternatives, in particular lignocellulose-based solutions, are highlighted. 

  • 34.
    Mauritzon, Albin
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Lönsamhet för elvägar: Beräkningsmodell för lönsamheten samt optimal andel elväg på en sträcka2019Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Elvägar kan vara en lösning för att ställa om till ett hållbarare transportsystem. Med elvägar kan elfordon laddas med el medan de åker på vägen. Det finns flera olika tekniker för elvägar som är under utveckling, och det finns flera demonstrationsanläggningar i Sverige. Elways AB har utvecklat en teknik som fungerar för både lastbilar och personbilar.

    I denna rapport har en beräkningsmodell för återbetalningstiden utarbetats, och förslag har getts på hur stor andel elväg som ska täcka en sträcka. En stor andel elväg på en sträcka innebär en större investeringskostnad för elvägen medan batterierna i fordonen kan vara små. Motsatt förhållande gäller vid liten andel elväg. Syftet med denna rapport är främst att ge underlag för att avgöra optimal andel elväg på en sträcka, baserat på lönsamhetsberäkningarna.

    Relevanta ekvationer har tagits fram genom litteraturstudier, resonemang och härledningar. En viktig parameter är batteriernas livslängd, och en modell har använts som beräknar det beroende på användning. Beräkningarna innehåller ett antal osäkra parametrar, varför resultatet för flera olika scenarier presenteras. Fler känslighetsanalyser visas dessutom i bilaga.

    4 huvudsakliga slutsatser kan dras utifrån resultatet:

    • Det kan räcka att täcka cirka 30–35% av utvalda sträckor med elväg, med jämna intervall. Lönsamheten blir god, och investeringskostnaden blir förhållandevis låg, vilket underlättar i ett tidigt utbyggnadsskede när osäkerheterna kring tekniker och lönsamheten är stora.
    • När sedan erfarenheterna och antalet användare ökar och osäkerheterna minskar, kan elvägarna byggas ut, både med fler sträckor och större andel på de befintliga sträckorna.
    • Med en lägre hastighetsbegränsning på sträckan räcker det med ännu mindre andel elväg och återbetalningstiden förkortas.
    • Med personbilar medräknade blir lönsamheten signifikant bättre än när endast lastbilar räknas med. Detta gäller åtminstone vid högre andel elväg.
  • 35.
    Medronho, Bruno
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik. University of Algarve, Faro, Portugal.
    Filipe, Alexandra
    University of Algarve, Faro, Portugal.
    Napso, Sofia
    Technion-Israel Institute of Technology, Haifa, Israel.
    Khalfin, Rafail L.
    Technion-Israel Institute of Technology, Haifa, Israel.
    Pereira, Rui F. P.
    University of Minho, Braga, Portugal.
    De Zea Bermudez, Verónica
    University of Trás-os-Montes e Alto Douro, Vila Real, Portugal.
    Romano, Anabela
    University of Algarve, Faro, Portugal.
    Cohen, Yachin
    Technion-Israel Institute of Technology, Haifa, Israel.
    Silk Fibroin Dissolution in Tetrabutylammonium Hydroxide Aqueous Solution2019Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, s. 4107-4116Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bombyx mori L. silk fibroin (SF) is widely used in different areas due to its ability to form durable and resilient materials with notable mechanical properties. However, in some of these applications the dissolution of SF is required, and this is not often straightforward due to its inability to be dissolved in the majority of common solvents. This work reports a novel approach to dissolve SF using 40 wt % aqueous tetrabutylammonium hydroxide, TBAOH(aq), at mild temperature. A thorough rheological study combined with small-angle X-ray scattering is presented to correlate the SF state in solution with changes in the rheological parameters. The scattering data suggest that the SF conformation in TBAOH(aq) is close to a random coil, possibly having some compact domains linked with flexible random chains. The radius of gyration (Rg) and the molecular weight (Mw) were estimated to be ca. 17.5 nm and 450 kDa, respectively, which are in good agreement with previous works. Nevertheless, a lower Mw value was deduced from rheometry (i.e., 321 kDa) demonstrating a low degree of depolymerization during dissolution in comparison to other harsh processes. The transition from a dilute to a semidilute regime coincides with the estimated critical concentration and is marked by the presence of a shear-thinning behavior in the flow curves, violation of the empirical Cox-Merz rule, and an upward increase in the activation energy. This work paves the way toward the development of advanced high-tech SF-based materials. © 2019 American Chemical Society.

  • 36.
    Melro, Elodie
    et al.
    University of Coimbra, Coimbra, Portugal.
    Filipe, Alexandra
    University of Coimbra, Coimbra, Portugal.
    Sousa, Dora
    University of Algarve, Faro, Portugal.
    Valente, Artur J. M.
    University of Coimbra, Coimbra, Portugal.
    Romano, Anabela
    University of Algarve, Faro, Portugal.
    Antunes, Filipe E.
    University of Coimbra, Coimbra, Portugal.
    Medronho, Bruno
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik. University of Algarve, Faro, Portugal.
    Dissolution of kraft lignin in alkaline solutions2020Ingår i: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 148, s. 688-695Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignins are among the most abundant renewable resources on the planet. However, their application is limited by the lack of efficient dissolution and extraction methodologies. In this work, a systematic and quantitative analysis of the dissolution efficiency of different alkaline-based aqueous systems (i.e. lithium hydroxide, LiOH; sodium hydroxide, NaOH; potassium hydroxide, KOH; cuprammonium hydroxide, CuAOH; tetrapropylammonium hydroxide, TPAOH and tetrabutylammonium hydroxide, TBAOH) is reported, for the first time, for kraft lignin. Phase maps were determined for all systems and lignin solubility was found to decrease in the following order: LiOH > NaOH > KOH > CuAOH > TPAOH > TBAOH, thus suggesting that the size of the cation plays an important role on its solubility. The π∗ parameter has an opposite trend to the solubility, supporting the idea that cations of smaller size favor lignin solubility. Dissolution was observed to increase exponentially above pH 9–10 being the LiOH system the most efficient. The soluble and insoluble fractions of lignin in 0.1 M NaOH were collected and analyzed by several techniques. Overall, data suggests a greater amount of simple aromatic compounds, preferentially containing sulfur, in the soluble fraction while the insoluble fraction is very similar to the native kraft lignin.

  • 37.
    Norgren, Robert
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för ekoteknik- och hållbart byggande. Ragn-Sells AB, Timrå, Sweden.
    Björkqvist, Olof
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Jonsson, Anders
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för ekoteknik- och hållbart byggande.
    Bio-sludge from the pulp and paper industry as feed for black soldier fly larvae: A study of critical factors for growth and survival2019Ingår i: Waste and Biomass Valorization, ISSN 1877-2641, E-ISSN 1877-265XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pulp and paper bio-sludge (PPBS) has low economic value and is therefore often composted or incinerated. The purpose of this work is to evaluate the feasibility of using PPBS to breed black soldier fly (Hermetia illucens) larvae (BSFL), so improving resource efficiency and supplying protein and fat to the animal feed market. BSFL were reared on PPBS in a climate chamber on a laboratory scale in order to assess nutrient deficiency, inhibition and whether the BSFL recycle the PPBS well or not. The PPBS used came from a chemi-thermomechanical pulp/groundwood pulp mill. The effect of supplementing nutrient solution added either into the PPBS or as a free liquid surface were studied. Prepupae dry weight, survival rate until prepupae stage and residual dry PPBS were measured. The addition of reference diet leachate into the PPBS did not have a significant impact on the weight of the prepupae (2.0 mg) but the survival rate was significantly higher (16.0 %). On the other hand, the addition of reference diet leachate as a free liquid surface had a significant impact on both the weight of the prepupae (4.8 mg) and the survival rate (25.7 %). The bio – conversion and PPBS – reduction was as best 0.4 % and 3.2 % respectively. This study has proven that the nutrients in PPBS are not readily available to the larvae. Addition of reference diet leachate increase the survival rate which opens up for possibilities of co-digestion. However, it is clear that under the tested conditions, BSFL is not recycling PPBS well and BSFL as a method for recycling of PPBS need further research.

  • 38.
    Owen Berghmark, Victor
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Investeringsunderlag för värmepump: Investeringsunderlag för ett byte från pelletspanna till värmepump i fastighet på södra Gotland2019Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Inom EU finns mål på att sänka utsläppen med 40% till år 2030. I Sverige står bygg och fastighetssektorn för cirka 21% av Sveriges totala utsläpp. För att lyckas nå EU:s klimatmål måste en konvertering till förnybara uppvärmningskällor ske. Region Gotland ansvarar idag för över 500 000m2 fastigheter. Många använder idag pellets till uppvärmning. Pellets ses som klimatneutralt och släpper därför inte ut mer koldioxid än vad trädet plockat upp. Ett problem som uppstår då pelletspannorna kräver underhåll och leveranser. Flera av Region Gotlands fastigheter ligger flera mil iväg från både leverantör och underhållspersonal vilket ökar kostnader och miljöpåverkan än mer. En av dessa fastigheter, brandstationen i Öja, ligger till grund för denna studie. Då det finns flera fastigheter med liknande förutsättningar kan rapporten användas som underlag för dessa. Studien undersöker ifall en konvertering från pelletspannan till en värmepump kan sänka kostnaderna och bidra till lägre utsläpp. Vid en konvertering till värmepump sänks systemtemperaturerna från 80/60 till 55/45 vilket kan skapa problem för befintliga radiatorer, rör och pumpar. Radiatorernas och rörens kompatibilitet med nya temperaturerna under söks därför i studien men pumpar utelämnas för en framtida studie. Med hjälp av transmissionsberäkningar och en formel baserad på grad dagar och tidigare energiförbrukning beräknades ett värmebehov för fastigheten på 23,8 kW den kallaste dagen på året. Med detta kunde tre värmepumplösningar tas fram. Samtliga lösningar innefattar även en ny ackumulatortank då den nuvarande är över 40 år gammal och har ett flertal brister. Med optimering av uppvärmningssystemet genom att sänka temperaturen i de fläktvärmda rummen till 15 grader kan värmebehovet sänkas med 4kW. En undersökning gällande installation av solfångare har även gjorts, där det inte visade sig lönsamt med dagens tappvarmvattenbehov.  Efter de dimensioneringar som gjorts framkommer även att två rörslingor behöver bytas, men att ett eventuellt radiatorbyte lämnas till efter en konvertering för att se om dessa behöver bytas. Undersökningarna visar även att de befintliga fläktvärmarna är överdimensionerade och inte behöver bytas. Utsläppsberäkningar visar att utsläppen kan minskas med 2565 kg CO2 eq per år vid en eventuell konvertering. Payoffmetoden har använts för att visa att de tre lösningarna har en mycket kort återbetalningstid mellan 3,9 år för luft/vattenvärmepumpar från CTC till 4,7 år för Thermias bergvärmelösning. Med hjälp av LCC kalkyler har lösningarna livstidskostnad tagits fram. Ställt mot den be fintliga pelletspannan uppgår besparingen till 879 000kr för Thermias lösning – 966 000kr för CTC:s lösning med en kalkylränta på 1,5%. Slutsatsen är därför att en konvertering till värmepump bör ske för att spara både ekonomiskt men även för att minska utsläppen.

  • 39.
    Rahman, Hafizur
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Modification of softwood kraft pulp requiring less energy in tissue paper production2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Modification of softwood kraft pulp by the addition of either polysulfide (PS) or sodium borohydride (NaBH4) has been shown to increase pulp yield due to a higher retention of hemicellulose. The modified pulps showed higher tensile index, especially at lower refining. It also showed a greater porosity of the fibre wall, indicating an increase in the swelling potential of the fibres thus helping to increase fibre flexibility, increase joint strength between the fibres and to raise the tensile index. However, the swelling increase associated with the higher hemicellulose content could also make dewatering more challenging because of the higher water retention of pulp. But recent studies showed the positive influence of increase pulp yield dominates over the negative influence of the higher hemicellulose content on dewatering properties, especially at lower refining. Studies simulating full-scale tissue dewatering conditions showed that pulps with higher hemicellulose content had a higher tensile index at the same dryness which was achieved in a shorter dwell-time. A given tensile index was also achieved with less refining energy. Therefore modification of the kraft pulping process is now a way to give high quality fibres for tissue paper production with less refining energy and lower drying energy costs.

  • 40.
    Rahman, Hafizur
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    An, Siwen
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Norlin, Börje
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Fröjdh, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Persson, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Engstrand, Per
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Maximized wood chip impregnation efficiency validated by new miniaturized X-ray fluorescence techniques2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Manufacturing of chemi-thermomechanical pulp (CTMP) is increasing due to increased demand for packaging materials such as cardboard as well as tissue and other hygiene products. Today high yield pulp (HYP) is produced from different wood species. It is well-known that chip-refining is normally responsible for more than 60% of the electric energy consumption in most high yield pulping process. There are opportunities to improve energy efficiency and quality stability in defibration processes by means of optimizing impregnation. Impregnation is a key unit operation in CTMP production as well as in all chemical pulping and biorefinery systems. The efficiency of the impregnation is known to be crucial (Ferritsius et al. 1985; Gorski et al. 2010). Early research showed difficulties to achieve even distribution of sulphite and sodium ions in wood chips resulting in inhomogeneous fibre properties (Bengtsson et al. 1988). Increased and homogenous sulphonation leads to reduced shive content, which is a key factor in all end product applications. To address this issue developing a new type miniaturized X-ray based technique (XRF) to measure local concentration of sulphur and sodium across wood chips and in individual fibres could become a key tool.

     

    The presence of elements as sulphur and sodium can be detected by X-ray fluorescence (XRF) or spectral absorption. At the XRF, images the surface of the sample using specific energies from K-shell or L-shell fluorescence. This method is investigated at the X-ray laboratory in Mid Sweden University research centre STC (Sensitive Things that Communicate) (Norlin et al. 2018). At the spectral absorption, images specific K-shell absorption energies in transmission X-ray images of the sample, a method widely used in medical diagnosis. This transmission method might also be further investigated for this application in the future (Frojdh et al. 2013; Reza et al. 2013). Both methods can be validated by using monoenergetic radiation from synchrotron facilities.

     

    An XRF imaging system uses a collimated X-ray source and a spectroscopic detector. The sample is scanned to make an image of the content of the substances of interest. A specific challenge in this case is that the low energy fluorescence photons from sulphur (S) and sodium (Na) are easily absorbed in air, which makes imaging in a different atmosphere necessary.

     

    The measurement setup has been simulated using MCNP (C. J. Werner, 2017) to validate the system setup and to select the correct, geometry, shielding, filtering and atmosphere for the measurement. The solution was to use a titanium box flooded with helium to minimise the absorption of fluorescence photons and to shield from scattered photons that might disturb the measurement, fig 1. A filter has been added to the X-ray source to make it nearly monoenergetic and to avoid emission of photons with energies close to the expected fluorescence. The system has been used to estimate sodium and sulphur content in low grammage handsheet (CTMP) or single wood chip samples. It is possible to build a laboratory instrument similar to the prototype setup to obtain the distribution of sodium and sulphur in XRF imaging.

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    Figure 1: Photograph of XRF measurement setup with of moveable Helium atmosphere Ti box

    However, the technique we are developing can become useful in mills to improve and control process efficiency, product properties and to find solutions to process problems in future. In addition, a more even distribution of the sulphonation can reduce specific energy demand in chip refining at certain shive content.

     

    References

     

    1.      Bengtsson, G., Simonson, R., Heitner, C., Beatson, R., and Ferguson, C. (1988): Chemimechanical pulping of birch wood chips, Part 2: Studies on impregnation of wood blocks using scanning electron microscopy and energy dispersive x-ray analysis, Nord. Pulp Paper Res. J. 3 (3), 132-138.

    2.      C. J. Werner, (2017): MCNP User's manual, Code Version 6.2, Los Alamos National Laboratory report, LA-UR-17-29981.

    3.      Ferritsius, O., and Moldenius, S. (1985): The effect of impregnation method on CTMP properties. In International Mechanical Pulping Conference Proceedings, SPCI, Stockholm (p. 91).

    4.      Frojdh, C., Norlin, B. and Frojdh, E. (2013): Spectral X-ray imaging with single photon processing detectors, Journal of Instrumentaion, Volume 8, Article number C02010.  

    5.      Gorski, D., Hill, J., Engstrand, P., and Johansson, L. (2010): Reduction of energy consumption in TMP refining through mechanical pre-treatment of wood chips, Nord. Pulp Paper Res. J, 25(2), 156-161.

    6.      Norlin, B., Reza, S., Fröjdh, C. and Nordin, T. (2018): Precision scan-imaging for paperboard quality inspection utilizing X-ray fluorescence, Journal of Instrumentation, Volume: 13, Article number C01021.

    7.      Reza, S., Norlin, B. and Thim, J. (2013): Non-destructive method to resolve the core and the coating on paperboard by spectroscopic x-ray imaging, Nord. Pulp Paper Res. J. 28 (3), 439-442.

     

  • 41.
    Rahman, Hafizur
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Engstrand, Per
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Modification of Softwood Kraft Pulp for Improved Tissue Paper2019Ingår i: TAPPI PaperCon Conference, Indianapolis, USA, May 5-8, 2019, 2019Konferensbidrag (Refereegranskat)
  • 42.
    Rahmani, Rizan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Structure elucidation of semiochemicals related to: Polygraphus poligraphus, Polygraphus punctifrons, Trioza apicalis, Whittleia retiella, Neodiprion edulicolus, Neodiprion scutellatus, Neodiprion knereri and Neodiprion virginianus2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
  • 43.
    Rahmani, Rizan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Andersson, Fredrik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Andersson, Martin N.
    Lund university, Lund.
    Yuvaraj, Jothi Kumar
    Lund university, Lund.
    Anderbrant, Olle
    Lund university, Lund.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Identification of sesquisabinene B in carrot (Daucus carota L.) leaves as a compound electrophysiologically active to the carrot psyllid (Trioza apicalis Forster)2019Ingår i: Chemoecology, ISSN 0937-7409, E-ISSN 1423-0445, Vol. 29, nr 3, s. 103-110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Carrot psyllid, Trioza apicalis Forster (Homoptera: Psylloidea: Triozidae) is one of the major insect pests of carrots (Daucus carota L.) in parts of northern and central Europe. Gas chromatography-single-sensillum recording (GC-SSR) previously confirmed several active compounds in a carrot leaf extract, but the most active compound remained unidentified. Mass fragmentation patterns observed from the unidentified active compound when analyzed by gas chromatography and mass spectrometry (GC-MS) was used to propose -sesquiphellandrene and -cis-bergamotene to be candidates as the unidentified compound. The compounds were synthesized and their mass spectra were nearly identical with the unknown active compound. But, the retention times differed from the compound in the carrot leaf extract. Thus, to obtain the unidentified compound pure enough and in adequate amounts for nuclear magnetic resonance (NMR) analysis, preparative gas chromatography was applied to separate and concentrate this biologically active compound. Analysis by liquid chromatography quadrupole time of flight mass spectrometry (LC-QTOF) confirmed the unidentified compound to be a compound with theformula of C15H24 and together with GC-MS, H-1 and C-13 NMR analysis sesquisabinene B was identified as the unidentified compound in the extract. GC-SSR was then used to finally confirm the biological activity of sesquisabinene B isolated from the carrot leaf extract via preparative GC.

  • 44.
    Rahmani, Rizan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Wallin, Erika
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Viklund, Lina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Schroeder, Martin
    Swedish University of Agricultural Sciences, Uppsala.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Identification and Field Assay of Two Aggregation Pheromone Components Emitted by Males of the Bark Beetle Polygraphus punctifrons (Coleoptera: Curculionidae)2019Ingår i: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 45, nr 4, s. 356-365Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The bark beetle Polygraphus punctifrons (Coleoptera: Curculionidae) is a species that feeds on Norway spruce (Picea abies) and is found in the Northern parts of Europe and Russia. The release of volatile organic compounds (VOCs) produced by males and females of P. punctifrons when the beetles bore into spruce stem sections in a laboratory environment was studied using solid phase microextraction (SPME). The sampled VOCs emitted by boring beetles were analysed by gas chromatography and mass spectrometry (GCMS). (+)-2-[(1R,2S)-1-Methyl-2-(prop-1-en-2-yl)cyclobutyl]ethanol [(+)-(1R,2S)-grandisol] and (−)-(R)-1-isopropyl-4-methyl-3-cyclohexen-1-ol [(−)-(R)-terpinen-4-ol] were identified to be male specific volatiles. The identity of the compounds was confirmed by comparison with synthetic samples. Field trials with synthetic compounds in Sweden showed that racemic grandisol per se was strongly attractive for both males and females, while (−)-(R)-terpinen-4-ol was not. Further, when adding (−)-(R)-terpinen-4-ol to rac-grandisol, a synergistic effect was observed as the trap catch of P. punctifrons was fourfold. (−)-(R)-Terpinen-4-ol by its own did not attract P. punctifrons but Polygraphus poligraphus, and the latter was also attracted to traps baited with a 10:90 mixture of the two compounds. Thus, we have identified (+)-(1R,2S)-grandisol as a main component and (−)-(R)-terpinen-4-ol as a minor component of the aggregation pheromone of P. punctifrons. This opens future possibilities to monitor and, if necessary, manage populations of P. punctifrons. 

  • 45.
    Sandberg, Christer
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik. Holmen Paper AB, Norrköping.
    Berg, Jan-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Engstrand, Per
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Low Consistency Refining Combined with Screen Fractionation: Reduction of Mechanical Pulping Process Complexity2019Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, nr 1, s. 882-894Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Process intensification is a process development methodology aimed at a considerable reduction in the energy consumption and process complexity. The approach has been applied to mechanical pulping process design. A process denoted as HC-LC-S consisting of single stage high consistency (HC) refining, followed by low consistency (LC) refining and screening was evaluated in mill trials at the Holmen Paper Braviken Mill in Sweden. After LC refining, the pulp was screened, and the reject fraction was fed back to LC refining. Two HC primary refiner types were evaluated, namely single disc (SD) and double disc (DD). Double disc chip refining was more suitable than SD refining for the HC-LC-S process because of the higher light scattering and lower shives content of the final pulp. The tensile index and shives content of the pulp produced with the DD-LC-S process was similar to that of the reference process, consisting of single stage DD refining and HC reject refining, but the fibre length and light scattering were somewhat lower. The specific refining energy was approximately 200 kWh/adt lower for the DD-LC-S process compared with the reference. Additionally, the auxiliary specific energy was 100 kWh/adt lower for the HC-LC-S processes, since a number of equipment units were omitted.

  • 46.
    Singh, Poonam
    et al.
    Univ Coimbra, Coimbra, Portugal.
    Magalhaes, Solange
    Univ Coimbra, Coimbra, Portugal.
    Alves, Luis
    Univ Coimbra, Coimbra, Portugal.
    Antunes, Filipe
    Univ Coimbra, Coimbra, Portugal.
    Miguel, Maria
    Univ Coimbra, Coimbra, Portugal.
    Lindman, Björn
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Medronho, Bruno
    Univ Algarve, Faro, Portugal.
    Cellulose-based edible films for probiotic entrapment2019Ingår i: Food Hydrocolloids, ISSN 0268-005X, E-ISSN 1873-7137, Vol. 88, s. 68-74Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Encapsulation with edible films is a promising approach that may solve the disadvantages associated with the use of bioactive compounds as food additives. This is particularly relevant in the case of probiotics, since their stability in food matrices and in the gastrointestinal tract may be rather poor. Therefore, new cellulose-based edible films have been successfully developed and characterized. Sodium carboxymethyl cellulose (CMC) and hydroxyethyl cellulose (HEC) were used for the film preparation and cross-linked with citric acid (CA) under reasonably mild conditions. Model probiotic bacteria (Lactobacillus rhamnosus GG) were incorporated in the films either during the film formation and casting or after the film synthesis, via bacteria diffusion and adsorption. The later approach could efficiently entrap and preserve viable bacteria. The mechanical properties and swelling ability could be tuned by varying the HEC/CMC ratio and the amount of CA. Moreover, the surface area and total pore volume of the films considerably decreased after cross-linking. Overall, these novel films are regarded as promising inexpensive and friendly matrices for food protection and packaging applications.

  • 47.
    Starrsjö, Sara
    et al.
    SCA R&D Centre.
    Sevastyanova, Olena
    KTH.
    Sandström, Peter
    SCA R&D Centre.
    Fiskari, Juha
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Lindstöm, Mikael
    KTH.
    Reduction of AOX formation in chlorine dioxide bleaching of softwood kraft pulp2019Ingår i: Proceedings of the 20th ISWFPC, Tokyo, Japan, 2019, s. A-09-Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This work examines the effect of pH on the AOX formation in a D stage in an ECF light bleaching sequence. Carbon dioxide was added to the pulp, generating a bicarbonate buffer system in situ and stabilizing the pH around 6 before chlorine dioxide addition. Stabilization of the pH around near-neutral was hypothesized to decrease the formation of strongly chlorinating species, such as Cl2 and HOCl, so that the AOX formation is reduced. Obtained results indicated that an addition of carbon dioxide could reduce the AOX content in the D stage effluents with up to 30% without significant effect on the ISO brightness. The pulp kappa number and viscosity were slightly higher when carbon dioxide had been added. The reduction in AOX formation seemed to be related to a lesser degradation of hexenuronic acid in the pulps that were bleached with a buffered D stage.

  • 48.
    Svedberg, Anna
    et al.
    MoRe Research AB, Örnsköldsvik.
    Renström, Pia
    MoRe Research AB, Örnsköldsvik.
    Nilsson, Sara
    MoRe Research AB, Örnsköldsvik.
    Norgren, Magnus
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Syverud, Kristin
    Paper and Fiber Research Institute, Trondheim, Norway .
    Heggset, Ellinor B.
    Paper and Fiber Research Institute, Trondheim, Norway .
    Cellulose replaces plastic in future packaging materials: Formation of cellulose-based foams with reinforcement of cellulose nanocrystals for porous architecture and thermal insulation2019Ingår i: EPNOE2019 Book of Abstracts, 2019, s. 232-Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper deals with the production of reinforced and highly porous cellulose/nanocellulosebased foams with excellent mechanical properties, aiming to replace fossil based materials for barrier against air, water and thermal insulation. A lab concept has been developed to produce porous solid foams via convective drying of wet foams. The ambition has been to produce solid foams of low density, in the same regions as expandable polystyrene (EPS) and polypropylene (EPP). Foams have been produced by varying the pulp fiber source and by varying the added amount of foaming agent and stabilizing/reinforcement agents. The wet foams have been characterized by the foam ability, foam stability, drainage capacity and drying behavior. The dried solid foams have been characterized both mechanically and structurally but also with respect to barrier properties and thermal insulation.

    The results demonstrate that cellulosic foams reinforced with cellulosic nanocrystals can be produced with superior foam stability and excellent mechanical properties, in densities similar to foamed materials based on EPS and EPP. The choice of pulp fiber and reinforcement agent, along with the foaming technology, is decisive for the foam stability, processability and mechanical properties of the solid foam. During the presentation, our experience on this will be highlighted.

  • 49.
    Tang, Yu-xing
    et al.
    Zhejiang Univ, Hangzhou, Peoples R China.
    Luo, Zhong-yang
    Zhejiang Univ, Hangzhou, Peoples R China.
    Yu, Chun-jiang
    Zhejiang Univ, Hangzhou, Peoples R China.
    Cen, Jian-meng
    Zhejiang Univ, Hangzhou, Peoples R China.
    Chen, Qian-yuan
    Fudan Univ, Shanghai, Peoples R China; Minist Environm & Ecol, State Environm Protect Key Lab Radiat Monitoring, Hangzhou, Zhejiang, Peoples R China.
    Zhang, Wennan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Determination of biomass-coal blending ratio by C-14 measurement in co-firing flue gas2019Ingår i: Journal Of Zhejiang University-Science A, ISSN 1673-565X, Vol. 20, nr 7, s. 475-486Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To verify the feasibility of using radiocarbon detection for the measurement of the biomass-coal blending ratio in co-firing heat and power plants, C-14 activity detection technology that uses benzene synthesis as the sample preparation method and a liquid scintillation counter as the detection instrument was studied. A benzene synthesis system was built to enrich carbon in the combustion flue gas in the form of benzene. The benzene sample was mixed with scintillator (butyl-PBD) and C-14 activity was measured using a liquid scintillation counter (Quantulus 1220). Three kinds of coal and six kinds of biomass were tested repeatedly. The measured C-14 activity was 0.3365 DPM/gC in Zhundong lignite, 0.2701 DPM/gC in Shenmu bitumite, and 0.3060 DPM/gC in Changzhi anthracite. These values were much higher than the instrument background activity. For the co-fired experiment, we used groups with biomass ratios (based on the carbon) of 6.51%, 12.95%, and 20.75%. A modified empirical expression to determine the biomass, coal blending ratio based on the C-14 activity measured in the co-firing flue gas, was proposed by analyzing and verifying measurement accuracy. From the C-14 measurements of the co-fired samples, the corresponding estimated biomass ratios were (5.540.48)%, (12.310.67)%, and (19.490.90)%. The absolute measurement error was around 1% for a typical biomass-coal co-firing application.

  • 50.
    Turunen, Maria
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för kemiteknik.
    Hållbar uppvärmning: Vilket är det mest hållbara alternativet för uppvärmning av en nybyggd villa i Östersunds tätort?2019Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Rapporten jämför frånluftsvärmepump, luft-vattenvärmepump, bergvärmepump, frånluftsvärmepump med fjärrvärmespets och pelletspanna för en nybyggd villa i Östersund. Det finns fem olika framtidsscenarier med varierande utfall av elmix samt elpris och är en känslighetsanalys för elprisets påverkan och miljöbelastning för respektive uppvärmningsalternativ. För att kunna jämföra de olika uppvärmningsalternativen så används ett referenshus som är baserat på tillverkarens uppgifter och fyra modellfamiljer som använder olika mycket energi. De olika familjerna används för att undersöka om utfallet för det mest hållbara uppvärmningsalternativet varierar för de olika livsstilarna.

    Resultatet baseras på de tre delarna inom hållbarhet nämligen ekonomisk, ekologisk och social hållbarhet. Den ekonomiska delen innefattar installationskostnader, inköpspris, ränta, driftskostnader och för pelletspannan ingår även kostnaden för byggnation av pelletsförråd och för bergvärmepumpen är även kostnaden för borrning av energibrunn inräknad. Den ekologiska hållbarheten bygger på att använda miljöbelastning som instrument och den baseras på vilken mängd energi som behövs för att säkerställa uppvärmning utav huset och presenteras som koldioxidekvivalenter, CO2eq, och det innebär att alla utsläpp relaterade till energins ursprung har omvandlats till likvärdig mängd koldioxid. Den sociala hållbarheten är beroende av de andra två delarna tillsammans då låg miljöbelastning innebär att fysiska och psykiska behov kan tillgodoses genom god inomhusmiljö med bra ventilation och behaglig värme samt att det finns en utemiljö som tillgodoser behovet av bland annat frisk luft och en levande natur och med en låg ekonomisk kostnad så har individen möjlighet att uppfylla sina drömmar.

    Det rapporten har kommit fram till är att bergvärmepumpen har den lägsta miljöbelastningen, den lägsta driftskostnaden oavsett scenario och livsstil samt den näst lägsta totalkostnaden vilket gör att den uppfyller rapportens kriterier för hållbarhet

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