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  • 1.
    Abbaszad Rafi, Abdolrahim
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Ibrahem, Ismail
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Copper nanoparticles on controlled pore glass (CPG) as highly efficient heterogeneous catalysts for “click reactions”2020In: Scientific Reports, E-ISSN 2045-2322, Vol. 10, no 1, article id 20547Article in journal (Refereed)
    Abstract [en]

    We herein report that supported copper nanoparticles (CuNPs) on commercially available controlled pore glass (CPG), which exhibit high mechanical, thermal and chemical stability as compared to other silica-based materials, serve as a useful heterogeneous catalyst system for 1,3-dipolar cycloadditions (“click” reactions) between terminal alkynes and organic azides under green chemistry conditions. The supported CuNPs-CPG catalyst exhibited a broad substrate scope and gave the corresponding triazole products in high yields. The CuNPs-CPG catalyst exhibit recyclability and could be reuced multiple times without contaminating the products with Cu. 

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  • 2.
    Abdulamir, Ahmed
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Utredning av värmeåtervinning från livsmedelsbutik som använder CO2 kylanläggning till byggnaden: Effektivisering av CO2 kylanläggning genom att utnyttja värmeåtervinning för att minska vattenförbrukning till nödkylan2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med detta arbete är att undersöka om värmeenergin från CO2 kyl-/frysaggregat i en livsmedelsbutik kan motsvara värmeenergibehovet till butiken och byggnaden samt undersöka möjligheten att minska vattenförbrukningen till att nödkyla värmeväxlare.  Genom litteraturstudie och datainsamling av relevanta parametrar, beräknades värmeenergibehovet för byggnaden, butiken och den producerade värmeenergin från kylanläggningen. En energibalansberäkning utfördes för att verifiera resultat och kartlägga hur värmeenergin fördelas i de olika delarna av värmeåtervinningskretsen. En förbättringsåtgärd presenterats för att sänka värmeåtervinnings returledningstemperatur och med det kan vattenförbrukningen minskas.

  • 3.
    Abdulgadir, Alamin
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. MoRe Research.
    Norgren, Sven
    MoRe Research.
    Persson, Johan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Performance Simulation of a Composite Filter Material Containing Mechanical Pulp Fibers, Microfibrillated Cellulose, and Cellulose Nanofibers2022In: Proceedings of the International Mechanical Pulping Conference, 2022, p. 160-Conference paper (Other academic)
    Abstract [en]

    Nonwoven fibrous materials with reticular support of an interconnected fiber network and a tortuous airflow pathway have been commonly used in filtration applications. To meet the criteria of filter efficiency and performance, the filter materials are recommended to contain different types of fibers such as mechanical pulp fibers, microfibrillated cellulose, cellulose nanofibers, and other polymer or synthetic fibers with a range of dimensions, i.e., length and diameter. Cellulose fibers in filter media possess irregular and complex structures with hollow or collapsed lumen structures owing to their refinement or pulping method. The development of an appropriate filter media model requires information on actual fiber characteristics. In this study, a simulation method was used to investigate the complex microstructures of filter media. The physical parameters such as fiber wall thickness, diameter, length, cross-section shapes, and curliness were obtained from fiber analyzers and scanning electron microscopy. Based on the experimental findings, GeoDict database comprising different types of common fiber models was constructed. 3-Dimensional fibrous models corresponding to the wet-laid binderless filter material were generated. Using the GeoDict modules, the pore size distributions, average pore sizes, air permeability, pressure drop and initial filter efficiency simulations were performed. The simulation results appear to be in close agreement with the experimental results. The incorporation of cellulose nanofibers resulted in reduced average pore sizes and air permeability of the filter material, thus enhancing the initial filter efficiency. The filter media developed a biobased material derived from pulp fibers for advanced applications such as medical facemask, and air filtration purposes.

  • 4.
    Abrahamsson, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Säsongslagring av överskottsenergi2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Genom att kartlägga smältugnarna och dess kylvattensystem inom Åkers Sweden AB har en studie genomförts för att analysera vilken potential det finns till att ytterligare återvinna överskottsenergi. Detta har genomförts för att uppfylla de av Sverige ställda miljö- och energi-mål till år 2030 som dels handlar om att vi behöver energieffektivisera våra processer och tillföra mindre energi för att uppnå samma resultat som tidigare.

    Uppdraget är genomfört på uppdrag av Åkers Ledningsgrupp som önskar förstå om det finns tekniska och ekonomiska förutsättningar att starta upp ett projekt för att investera i ett energilager. Överskottsenergi som idag inte kan tillvaratas kyls bort med sjövatten vilket kan betraktas som ett rent energislöseri.

    Resultatet påvisar att det finns en potential till att återvinna ytterligare 2 GWh överskottsenergi vilka är möjliga att lagra i ett energilager till en investeringskostnad på 21 MSEK.

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  • 5.
    Ahokas, Karri
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Identifiering av värmekällor som kan minska behovet av direktånga i mixgroparna på Ortvikens pappersbruk2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    SCA Ortviken är ett pappersbruk i Sundsvall. Arbetets syfte var att identifiera åtgärder som leder till minskat behov att direktånga. Examensarbetet är delat i två deluppgifter.

    I december 2015 stängdes pappersmaskin 2 ner. Sedan dess har fördelningen av sju stycken värmeväxlare som förvärmer bakvattnet i papperstillverkning varit oförändrad.

    Direktånga används för att kompensera för värmebehov som inte nås med värmeväxlarna. Ångdata från pappersmaskinerna kartlagdes för att identifiera vilken fördelning av värmeväxlare skulle ledas till största effektivitet. Effekterna i värmeväxlare beräknades med NTU-metoden. Den effektivaste fördelning av värmeväxlare är den rådande fördelningen om inte värmeväxlare sju kopplas till pappersmaskin fem.

    Ångan från rejektraffinörer R81-R84 måste släppas ut i luften på grund av tryckförlusterna i den långa ledningen som leder ångan till ångomformaren. Syftet med uppgiften är att beräkna hur mycket ånga kan tas till vara på genom att leda ångan till en venturiskrubber som tar vara på värmen från andra processer.  Ångdata från bruket analyserades och genomarbetades så att ångflödet kunde simuleras med ett tryckförlust program, fluidflow3. Simuleringen gav resultatet att ungefär 17 500 MWh per år skulle kunna tas till vara på, om ånga skulle ledas till venturiskrubbern.

    Det har gjorts förenklingar i beräkningar och simuleringar men resultatet från uppgifterna ger en bra uppskattning på storleksordning på möjliga besparingar.

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  • 6.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Abbaszad Rafi, Abdolrahim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Persson, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Marksted, Kajsa
    Hilden, Lars
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Improving the mechanical properties of CTMP fibers by combining synergistic organocatalytic/polyelectrolyte complex surface engineering with sulfite pretreatment2022In: Proceedings of the International Mechanical Pulping Conference, 2022, p. 149-Conference paper (Other academic)
    Abstract [en]

    Fabrication of paper-based packaging materials is increasing and the challenge is developing a sustainable process to manufacture the materials that can compete with plastics. Employing stronger fiber in production of fiber-based materials improves the efficiency of fabrication process by using a reduced amount of biomass. Cationic starch is a well-known polysaccharide that has been introduced to paper and paperboard fibers to improve the mechanical properties of lignocellulosic fibers. The polyelectrolyte (PE) multilayer method has been popularized as a new and interesting technique to enhance the adsorption of cationic starch on the fiber for improving the strength properties of chemi-thermomechanical pulp (CTMP), chemical and kraft pulps. We have shown in our previous work that the synergistic combination of organocatalysis and PE complexes improved the mechanical properties of CTMP and TMP. In this work, we chose to expand this concept by integrating it with low-dose sulfite pretreatment of wood chips in preparation of CTMP. Thus, CTMP produced by initial sulfite pre-treatment was next surface engineered by synergistic combination of organocatalysis and PE complexes using organic acids as catalysts. The CTMP pulps, which contains 0.1-0.24 wt.% sulfur, produced by our novel pulp-engineering strategy shows a dramatic strength increase (Z- strength: up to 100 %) as compared to no surface engineering. While only sulfite pre-treatment and PE-complex surface engineering were able to improve the strength properties, it was only when the organic catalysts was present that the highest strength improvements were reached. Thus, a clear synergistic effect of the catalyst was observed.

  • 7.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Abbaszad Rafi, Abdolrahim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Cellulosic Materials: Sustainable Surface Engineering of Lignocellulose and Cellulose by Synergistic Combination of Metal-Free Catalysis and Polyelectrolyte Complexes2019In: Global Challenges, E-ISSN 2056-6646, Vol. 3, no 7, article id 1970071Article in journal (Refereed)
    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.

  • 8.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Abbaszad Rafi, Abdolrahim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sustainable Surface Engineering of Lignocellulose and Cellulose by Synergistic Combination of Metal‐Free Catalysis and Polyelectrolyte Complexes2019In: Global Challenges, E-ISSN 2056-6646, Vol. 3, article id 1900018Article in journal (Refereed)
    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.

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  • 9.
    Alopaeus, Ville
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Aalto University.
    Modeling surfactant and drop size dynamics in polydisperse liquid-liquid systems with population balances2022In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 248, article id 117269Article in journal (Refereed)
    Abstract [en]

    A population balance framework based on high order moment conserving method of classes is extended to capture surfactant dynamics and its effect on drop size distributions. The proposed method is flexible for incorporating various closure models for drop breakage and coalescence, mass transfer, and physical equilibria between dispersed and continuous phase as well as for adsorption to the interface. The method is first schematically explained and derived in a generic form, and then appropriate closure models are discussed. The model is accurate and fast and can be implemented in process models, parameter optimization algorithms, and computational fluid dynamics software due to its high accuracy with limited number of additional variables. 

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  • 10. Alves, Luis
    et al.
    Medronho, Bruno
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. University of Algarve.
    Filipe, Alexandra
    Romano, Anabela
    Rasteiro, Maria G.
    Lindman, Björn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Topgaard, Daniel
    Davidovich, Irina
    Talmon, Yeshayahu
    Revisiting the dissolution of cellulose in H3PO4(aq) through cryo-TEM, PTssNMR and DWS2021In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 252, article id 117122Article in journal (Refereed)
    Abstract [en]

    Cellulose can be dissolved in concentrated acidic aqueous solvents forming extremely viscous solutions, and, in some cases, liquid crystalline phases. In this work, the concentrated phosphoric acid aqueous solvent is revisited implementing a set of advanced techniques, such as cryo-transmission electronic microscopy (cryo-TEM), polarization transfer solid-state nuclear magnetic resonance (PTssNMR), and diffusing wave spectroscopy (DWS). Cryo-TEM images confirm that this solvent system is capable to efficiently dissolve cellulose. No cellulose particles, fibrils, or aggregates are visible. Conversely, PTssNMR revealed a dominant CP signal at 25 °C, characteristic of C-H bond reorientation with correlation time longer than 100 ns and/or order parameter above 0.5, which was ascribed to a transient gel-like network or an anisotropic liquid crystalline phase. Increasing the temperature leads to a gradual transition from CP to INEPT-dominant signal and a loss of birefringence in optical microscopy, suggesting an anisotropic-to-isotropic phase transition. Finally, an excellent agreement between optical microrheology and conventional mechanical rheometry was also obtained. 

  • 11.
    Alzhairi, Husam
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Teknisk och ekonomisk analys av vätgassystem i hushåll: Storlek och kostnader för ett vätgassystem i fyra olika städer i Sverige2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the work is to investigate whether energy storage in the form of hydrogen produced from solar cell can be suitable technology for detached houses located at four different regions of Sweden from a practical and economic perspective. The energy consumption and economic analysis was made in four cases: 

    1.  with waste heat recovery.

    2. without waste heat recovery.

    3. with an electric car and waste heat recovery.

    4.  with a fuel cell car and waste heat recovery.

     The results show that the hydrogen system is economically expensive due to low system efficiency caused by the mutilation of several unit efficiencies of electrolysis, fuel cell, hydrogen compression etc. for winter season. Nevertheless, household hydrogen system is technically possible. Such a system can be economically benefit if the energy consumption for house heating is covered from another heat source such as pellet burner and district heating. In Kiruna, a larger number of solar panels is required with an area that can be up to 400 m2 or even larger, whereas in Lund, only about 200 m2 is needed. As a result, the hydrogen system is unsuitable for cities that have low solar radiation or have a greater heat demand. In a technical and economic comparison, an electric car is currently a much better green choice for a house than for a hydrogen car. The hydrogen system is economically expensive due to low energy efficiency for the winter season but is technically feasible.

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  • 12. Anderbrant, Olle
    et al.
    Lyons, D. Barry
    Bång, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Article sex pheromone of the introduced pine sawfly, diprion similis, revisited to define a useful monitoring lure: Deviating chiral composition and behavioural responses compared to earlier reports2021In: Insects, E-ISSN 2075-4450, Vol. 12, no 10, article id 886Article in journal (Refereed)
    Abstract [en]

    Extracts of Diprion similis females contained about 15 ng of the sex pheromone precursor 3,7‐dimethylpentadecan‐2‐ol per female. After derivatisation with (S)‐2‐acetoxypropanoyl chloride, we found that the major stereoisomer in the extract was (2S,3R,7R)‐3,7‐dimethylpentadecan‐2‐ol. Small amounts of other stereoisomers of 3,7‐dimethylpentadecan‐2‐ol were also identified in the extract, namely 1% of (2R,3S,7S), 0.3% (2R,3R,7R) and 0.4% of (2R,3R,7S). An unknown fifth substance showed a very similar spectrum to 3,7‐dimethylpentadecan‐2‐ol, both in SIM and full scan mode. None of the earlier suggested behavioural synergistic isomers ((2S,3S,7S), (2S,3S,7R) and (2S,3R,7S)) were detected in the extracts. In field tests in Ontario, Canada, the earlier identified main pheromone component, viz. the propanoate of (2S,3R,7R)‐3,7‐dimethylpentadecan‐2‐ol, was tested alone and in combination with other stereoisomers, earlier reported to be synergistic. No synergistic effects were detected and the threo four‐isomer blend was as attractive as the pure main compound. Thus, one of the few examples of a diprionid sawfly using more than one substance in its sex pheromone could not be confirmed. The results also suggest that monitoring programs can use the more easily synthesized threo‐blend without losing efficiency. Furthermore, the study suggests that other diprionid pheromones may benefit from a reinvestigation, to clarify possible synergistic effects of stereoisomers. 

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  • 13.
    Axelsson, K.
    et al.
    KTH.
    Zendegi-Shiraz, A.
    KTH; Ferdowsi University of Mashhad, Mashhad, Iran.
    Swedjemark, G.
    Skogforsk, Ekebo, Svalöv.
    Borg-Karlson, Anna-Karin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. KTH.
    Zhao, T.
    Örebro University.
    Chemical defence responses of Norway spruce to two fungal pathogens2020In: Forest Pathology, ISSN 1437-4781, E-ISSN 1439-0329, Vol. 50, no 6, article id e12640Article in journal (Refereed)
    Abstract [en]

    Constitutive and inducible terpene production is involved in conifer resistance against insects and fungal infestations. To gain knowledge about local defence responses of Norway spruce bark against pathogens and to find potential chemical markers for resistance breeding, we inoculated the stem of 8-year-old Norway spruce (Picea abies) clonal trees with both Endoconidiophora polonica (Ep, a common fungal pathogen associated with the spruce bark beetle Ips typographus) and Heterobasidion parviporum (Hp, a severe pathogen causing root and stem rot disease). Three weeks after inoculation, the fungal-inoculated and intact bark from each tree was sampled. The terpenes in tree bark were extracted with hexane and characterized by gas chromatography–mass spectrometry (GC-MS). The two fungi induced varied terpene responses in the four spruce clones used. Three of the clones showed a 2.3-fold to 5.7-fold stronger terpene response to Hp relative to Ep inoculation, while one clone responded similarly to inoculation with the two fungal pathogens. The amount of the diterpenes thunbergol and geranyllinalool varied between the clones. The level of thunbergol was higher in both intact and fungal-inoculated bark from the less susceptible clones compared with the more susceptible clones. Geranyllinalool was present in higher amounts in the susceptible clones and is thus a possible marker for susceptibility. Our observations show that Norway spruce employs a similar chemical mechanism against the two fungal pathogens. Based on the present and earlier published data, we suggest that certain Norway spruce genotypes have a strong defence reaction against these two pathogens. The diterpenes thunbergol and geranyllinalool might be useful markers of susceptibility in tree-breeding programmes and should be the focus of further detailed investigations. 

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  • 14.
    Barea-Sepulveda, Marta
    et al.
    Univ Cadiz, Fac Sci, Dept Analyt Chem, IVAGRO,Agrifood Campus Int Excellence CeiA3, Puerto Real 11510, Spain..
    Duarte, Hugo
    Univ Algarve, Fac Ciencias & Tecnol, MED Mediterranean Inst Agr Environm & Dev, Campus Gambelas,Ed 8, P-8005139 Faro, Portugal..
    Jose Aliano-Gonzalez, Maria
    Univ Cadiz, Fac Sci, Dept Analyt Chem, IVAGRO,Agrifood Campus Int Excellence CeiA3, Puerto Real 11510, Spain.;Univ Algarve, Fac Ciencias & Tecnol, MED Mediterranean Inst Agr Environm & Dev, Campus Gambelas,Ed 8, P-8005139 Faro, Portugal..
    Romano, Anabela
    Univ Algarve, Fac Ciencias & Tecnol, MED Mediterranean Inst Agr Environm & Dev, Campus Gambelas,Ed 8, P-8005139 Faro, Portugal..
    Medronho, Bruno
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Univ Algarve, Portugal.
    Total Ion Chromatogram and Total Ion Mass Spectrum as Alternative Tools for Detection and Discrimination (A Review)2022In: CHEMOSENSORS, ISSN 2227-9040, Vol. 10, no 11, article id 465Article, review/survey (Refereed)
    Abstract [en]

    Gas chromatography (GC) and mass spectrometry (MS) are widely used techniques in the analysis of complex mixtures due to their various advantages, such as high selectivity, reproducibility, precision, and sensitivity. However, the data processing is often complex and time-consuming and requires a great deal of experience, which might be a serious drawback in certain areas, such as quality control, or regarding research in the field of medicine or forensic sciences, where time plays a crucial role. For these reasons, some authors have proposed the use of alternative data processing approaches, such as the total ion chromatogram or total mass spectrum, allowing these techniques to be treated as sensors where each retention time or ratio m/z acts as a sensor collecting total intensities. In this way, the main advantages associated with both techniques are maintained, but the outcomes from the analysis can be reached in a faster, simpler, and an almost automated way. In this review, the main features of the GC- and MS-based analysis methodologies and the ways in which to apply them are highlighted. Moreover, their implementation in different fields, such as agri-food, forensics, environmental sciences, or medicine is discussed, highlighting important advantages as well as limitations.

  • 15.
    Berg, Jan-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hellstadius, Börje
    BillerudKorsnäs.
    Lundfors, Mikael
    Valmet.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Low-consistency refining of CTMP targeting high strength and bulk: effect of filling pattern and trial scale2021In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 36, no 1, p. 33-41, article id 61Article in journal (Refereed)
    Abstract [en]

    Chemithermomechanical pulp (CTMP) is often used in central layers of multiply paperboards due to its high bulk and strength. Such a CTMP should consist of well-separated undamaged fibres with sufficient bonding capacity. The basic objective of this work is to optimize process conditions in low-consistency (LC) refining, i. e. to select or ultimately develop new optimal LC refiner filling patterns, in order to produce fibrillar fines and improve the separation of fibres from each other while preserving the natural fibre morphology as much as possible. Furthermore, the aim is to evaluate if this type of work can be done at laboratory-scale or if it is necessary to run trials in pilot- or mill-scale in order to get relevant answers. First stage CTMP made from Norway spruce (Picea abies) was LC refined in mill-, pilot- and laboratory-scale trials and with different filling patterns. The results show that an LR1 laboratory refiner can favourably be used instead of larger refiners in order to characterize CTMP with regard to tensile index and z-strength versus bulk. A fine filling pattern resulted in CTMP with higher tensile index, z-strength and energy efficiency at maintained bulk compared to a standard filling pattern.

  • 16.
    Berg, Jan-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Persson, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hellstadius, Börje
    Billerud Korsnäs AB, SE-80181 Gävle, Sweden..
    Edlund, Henrik
    Billerud Korsnäs AB, SE-71880 Frövi, Sweden..
    Granfeldt, Thomas
    Lundfors, Mikael
    Valmet AB, Refiner Segments, Vretenvagen 11, SE-17154 Solna, Sweden..
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Refining gentleness - a key to bulky CTMP2022In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 37, no 2, p. 349-355Article in journal (Refereed)
    Abstract [en]

    Chemithermomechanical pulp (CTMP) is often used in middle layers of multiply paperboards due to its high bulk at specified strength. Such a CTMP should consist of well-separated undamaged fibres with sufficient bonding capacity. The basic objective of this work is to examine the effect of refining on bulk, taking into account conditions such as temperature, sulphonation, refining gap and refiner size. First stage CTMP made from Norway spruce (Picea abies) were produced in pilot and mill scale trials. Two new parameters, Equivalent temperature related to softness and Refining gentleness are introduced that take into account refining conditions as actual temperature, softening temperature, bound sulphonate content, refining gap and refiner diameter. The results show that bulk increases linearly with refining gentleness.

  • 17.
    Bergman, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Carbon capture in biomass combustion plants using promoted potassium carbonate solutions: A cost and safety evaluation2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Biomass combustion can be seen as CO2 neutral, thereby biomass combustion plants can have negative CO2 emissions if retrofitted with post combustion capture (PCC) technology using liquid absorbents. Monoethanolamine (MEA) has been used for carbon capture in coal combustion plants but are not suitable for use in biomass combustion plants due to corrosion and high solvent regeneration cost. Instead, the hot potassium carbonate (HPC) process using potassium carbonate (K2CO3) as absorbent show better attributes in these aspects. Although, K2CO3 has slow reaction kinetics with CO2 which need to be improved using promoters. Piperazine is the most tested promoter but are hazardous to humans. Recent research has revealed promising alternatives, among these different amino acid salts such as glycine, proline, and isonipecotic acid which are chemically benign. Biomass flue gas composition vary depending on the biomass fuel characteristics. How this affects the degradation and potential formation of hazardous substances need to be studied further. Biomass combustion plants are generally equipped with flue gas condensation systems, making retrofitting more feasible due to increased system flexibility and energy recovery options. The operation costs of carbon capture and sequestration (CCS) in biomass combustion plants need to be monitored to optimize the plant revenue. To make implementation of HPC in biomass combustion plants a reality, piperazine should be used as promoter. Meanwhile, research should focus on improving the absorption rate in HPC process with more chemically safe promoters.

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  • 18.
    Bergström, Per
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hossain, Shakhawath
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Uesaka, Tetsu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Scaling Behaviour of Strength of 3D-, Semi-flexible-, Cross-linked Fibre Network2019In: International Journal of Solids and Structures, ISSN 0020-7683, E-ISSN 1879-2146, Vol. 166, no July 2019, p. 68-74Article in journal (Refereed)
    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.

  • 19.
    Bergström, Robin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Reducering av utsläpp till luft: Optimering av SCA Ortvikens drift och underhållsarbete2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    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.

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  • 20. Bettelli, M. A.
    et al.
    Capezza, A. J.
    Nilsson, Fritjof
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Johansson, E.
    Olsson, R. T.
    Hedenqvist, M. S.
    Sustainable Wheat Protein Biofoams: Dry Upscalable Extrusion at Low Temperature2022In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 23, no 12, p. 5116-5126Article in journal (Refereed)
    Abstract [en]

    Glycerol-plasticized wheat gluten was explored for producing soft high-density biofoams using dry upscalable extrusion (avoiding purposely added water). The largest pore size was obtained when using the food grade ammonium bicarbonate (ABC) as blowing agent, also resulting in the highest saline liquid uptake. Foams were, however, also obtained without adding a blowing agent, possibly due to a rapid moisture uptake by the dried protein powder when fed to the extruder. ABC's low decomposition temperature enabled extrusion of the material at a temperature as low as 70 °C, well below the protein aggregation temperature. Sodium bicarbonate (SBC), the most common food-grade blowing agent, did not yield the same high foam qualities. SBC's alkalinity, and the need to use a higher processing temperature (120 °C), resulted in high protein cross-linking and aggregation. The results show the potential of an energy-efficient and industrially upscalable low-temperature foam extrusion process for competitive production of sustainable biofoams using inexpensive and readily available protein obtained from industrial biomass (wheat gluten). 

  • 21. Bijok, Nicolaus
    et al.
    Fiskari, Juha
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Gustafson, Richard R.
    Alopaeus, Ville
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Aalto University, Finland.
    Modelling the kraft pulping process on a fibre scale by considering the intrinsic heterogeneous nature of the lignocellulosic feedstock2022In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 438, article id 135548Article in journal (Refereed)
    Abstract [en]

    Renewable raw materials such as lignocellulose are inherently complex and demanding in chemical processing compared to petroleum-based feedstocks. This article addresses the challenge of developing a general model framework for modelling lignocellulosic feedstock on a fibre scale, considering its inherent heterogeneous nature in terms of the fundamental chemical component distribution in addition to its anisotropic structural properties. The presented model is tested and validated for the well-established kraft pulping process. Simulations and parameter estimation are carried out to investigate the kappa number distribution of softwood fibres during kraft pulping by using experimental data from the literature showing non-uniform delignification. A moving grid discretisation method for the distributed concentration variables is used to predict the reaction of the wood solids. The results suggest that an inherent fundamental chemical component distribution can be hypothesised as one source of the non-uniform delignification. The model indicates that a Gaussian distribution can be assumed for the initial lignin concentration within softwood. In addition, an investigation of the lignin kinetics suggests that the reactivity of lignin during kraft pulping decreases as the delignification progresses. 

  • 22.
    Björk, Elisabeth
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Bouveng, Mikael
    RISE, Stockholm, Sweden.
    Vomhoff, Hannes
    Holmen, Stockholm, Sweden.
    Production of a fine fraction of refined kraft pulp using micro-perforated screens2020In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669Article in journal (Refereed)
  • 23.
    Björk, Elisabeth
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Bouveng, Mikael
    RISE, Stockholm, Sweden.
    Vomhoff, Hannes
    Holmen, Stockholm, Sweden.
    Production of a fine fraction using micro-perforated screens2020In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 35, no 4, p. 611-620Article in journal (Refereed)
    Abstract [en]

    The objective for this work was to investigate the possibility to use a pressure screen equipped with a micro-perforated screen basket to produce a fine fraction from bleached chemical pulp. Trials were performed with unrefined bleached chemical hardwood pulp, and with unrefined and refined bleached chemical softwood pulp. The effect of feed concentration, feed flow, and volumetric fine fraction flow was evaluated. The difference between the fine fraction (i. e. the particles passing the screen) and the feed was analysed by studying the fibre morphology. The results showed that high feed concentration was positive for both the fine fraction concentration and the separation efficiency. A higher fine fraction concentration was also obtained when using hardwood pulp, which was explained by the shorter fibre length. Refining of the pulp prior to the fractionation proved beneficial, as a larger share of the refined pulp passed the screen, resulting in a twice as high concentration of the fine fraction when compared to unrefined pulp.

  • 24.
    Björk, Elisabeth
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. RISE Res Inst Sweden, Pulp Papermaking & Packaging, Stockholm, Sweden.
    Bouveng, Mikael
    RISE Res Inst Sweden, Pulp Papermaking & Packaging, Stockholm, Sweden..
    Vomhoff, Hannes
    Holmen AB, Stockholm, Sweden..
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Use of fines-enriched chemical pulp to increase CTMP strength2021In: TAPPI Journal, ISSN 0734-1415, Vol. 20, no 4, p. 255-263Article in journal (Refereed)
    Abstract [en]

    In this study, fines-enriched pulp (FE-pulp)-the fine fraction of highly-refined kraft pulp-was benchmarked against highly-refined kraft pulp (HRK-pulp) as a strength agent in eucalyptus chemithermomechanical pulp (CTMP). Both the FE-pulp and the HRK-pulp were produced from unbleached softwood kraft pulp, and equal amounts of those strength agents were added to the original CTMP, as well as to washed CTMP, where most of the fines had been removed. The effects of the added strength agents were evaluated with laboratory handsheets. The FE-pulp proved to be twice as effective as HRK-pulp. Both HRK-pulp and FE-pulp increased the strength of the CTMP handsheets. The bulk of the handsheets decreased, however, as well as the drainability. The addition of 5% FE-pulp resulted in the same strength increase as an addition of 10% HRK-pulp, as well as the same decrease in bulk and CSF. For the handsheets of washed CTMP, the strengths were not measurable; the CTMP lost the sheet strength when the CTMP-fines content was reduced through washing. The reduced strength properties were compensated for by the addition of chemical pulp fines that proved to be an efficient strength agent. The addition of 5% FE-pulp restored the strength values, and at a higher bulk and higher drainability. Application: In this study, we show how the strength of a CTMP sheet can be improved by adding fine material from kraft pulp.

  • 25.
    Björk, Elisabeth
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Rise.
    Vomhoff, Hannes
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Production of fines from refined kraft pulp by fractionation with micro-perforated screens2021In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 36, no 3, p. 456-464Article in journal (Refereed)
    Abstract [en]

    The objective in this work was to obtain a fine fraction of kraft pulp, with as high concentration as possible, in a pilot-scale fractionation with micro-perforated screen baskets. The influence of screen basket surface, hole size, feed concentration, pulp type and refining segment design was investigated. The results showed that a smooth screen basket surface improved the fractionation efficiency of the unrefined pulp compared to a profiled screen basket, despite a larger hole size. A significantly higher fine fraction concentration was obtained when using refined hardwood pulp compared to when using softwood pulp, which was explained with its lower average fibre length and narrower and thus more flexible fibre fragments. The pilot trials also showed that the screening process could be operated at feed concentrations similar to those directly after a refiner, 30-40 g/l. This was demonstrated in a process layout with partial recirculation where a refiner and a micro-perforated screen basket were operated in series in pilot scale. 

  • 26.
    Blomquist, Nicklas
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Alimadadi, Majid
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hummelgård, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Olsen, Martin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Effects of Geometry on Large-scale Tube-shear Exfoliation of Multilayer Graphene and Nanographite in Water2019In: Scientific Reports, E-ISSN 2045-2322, Vol. 9, no 1, article id 8966Article in journal (Refereed)
    Abstract [en]

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

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  • 27.
    Blomquist, Nicklas
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Koppolu, R.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Toivakka, M.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Influence of Substrate in Slot-die Coating of Nanographite/Nanocelluose Electrodes for SupercapacitorsManuscript (preprint) (Other academic)
  • 28.
    Blomquist, Nicklas
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Koppolu, Rajesh
    Åbo Akademi.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Toivakka, Martti
    Åbo Akademi.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Influence of Substrate in Roll-to-roll Coated Nanographite Electrodes for Metal-free Supercapacitors2020In: Scientific Reports, E-ISSN 2045-2322, Vol. 10, no 1, article id 5282Article in journal (Refereed)
    Abstract [en]

    Due to the high electric conductivity and large surface area of nanographites, such as graphene and graphite nanoplatlets, these materials have gained a large interest for use in energy storage devices. However, due to the thin flake geometry, the viscosity of aqueous suspensions containing these materials is high even at low solids contents. This together with the use of high viscosity bio-based binders makes it challenging to coat in a roll-to-roll process with sufficient coating thickness. Electrode materials for commercial energy storage devices are often suspended by organic solvents at high solids contents and coated onto metal foils used as current-collectors. Another interesting approach is to coat the electrode onto the separator, to enable large-scale production of flat cell stacks. Here, we demonstrate an alternative, water-based approach that utilize slot-die coating to coat aqueous nanographite suspension with nanocellulose binder onto the paper separator, and onto the current collector as reference, in aqueous metal-free supercapacitors. The results show that the difference in device equivalent series resistance (ESR) due to interfacial resistance between electrode and current collector was much lower than expected and thus similar or lower compared to other studies with a aqueous supercapacitors. This indicates that electrode coated paper separator substrates could be a promising approach and a possible route for manufacturing of low-cost, environmentally friendly and metal-free energy storage devices. 

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  • 29.
    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
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Identification of (Z)-8-Heptadecene and n-Pentadecane as Electrophysiologically Active Compounds in Ophrys insectifera and Its Argogorytes Pollinator2020In: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 21, no 2Article in journal (Refereed)
    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.

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  • 30. Borrega, M.
    et al.
    Hinkka, V.
    Hörhammer, H.
    Kataja, K.
    Kenttä, E.
    Ketoja, Jukka A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Palmgren, R.
    Salo, M.
    Sundqvist-Andberg, H.
    Tanaka, A.
    Utilizing and Valorizing Oat and Barley Straw as an Alternative Source of Lignocellulosic Fibers2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 21, article id 7826Article in journal (Refereed)
    Abstract [en]

    The transition to sustainable, biodegradable, and recyclable materials requires new sources of cellulose fibers that are already used in large volumes by forest industries. Oat and barley straws provide interesting alternatives to wood fibers in lightweight material applications because of their similar chemical composition. Here we investigate processing and material forming concepts, which would enable strong fiber network structures for various applications. The idea is to apply mild pretreatment processing that could be distributed locally so that the logistics of the raw material collection could be made efficient. The actual material production would then combine foam-forming and hot-pressing operations that allow using all fractions of fiber materials with minimal waste. We aimed to study the technical features of this type of processing on a laboratory scale. The homogeneity of the sheet samples was very much affected by whether the raw material was mechanically refined or not. Straw fibers did not form a bond spontaneously with one another after drying the sheets, but their effective bonding required a subsequent hot pressing operation. The mechanical properties of the formed materials were at a similar level as those of the conventional wood-fiber webs. In addition to the technical aspects of materials, we also discuss the business opportunities and system-level requirements of using straw as an alternative source of lignocellulosic fibers. 

  • 31. Borrero-Echeverry, F.
    et al.
    Solum, M.
    Trona, F.
    Becher, P. G.
    Wallin, Erika A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Bengtsson, M.
    Witzgall, P.
    Lebreton, S.
    The female sex pheromone (Z)-4-undecenal mediates flight attraction and courtship in Drosophila melanogaster2022In: Journal of insect physiology, ISSN 0022-1910, E-ISSN 1879-1611, Vol. 137, article id 104355Article in journal (Refereed)
    Abstract [en]

    Specific mate communication and recognition underlies reproduction and hence speciation. Our study provides new insights in Drosophila melanogaster premating olfactory communication. Mate communication evolves during adaptation to ecological niches and makes use of social signals and habitat cues. Female-produced, species-specific volatile pheromone (Z)-4-undecenal (Z4-11Al) and male pheromone (Z)-11-octadecenyl acetate (cVA) interact with food odour in a sex-specific manner. Furthermore, Z4-11Al, which mediates upwind flight attraction in both sexes, also elicits courtship in experienced males. Two isoforms of the olfactory receptor Or69a are co-expressed in the same olfactory sensory neurons. Z4-11Al is perceived via Or69aB, while the food odorant (R)-linalool is a main ligand for the other variant, Or69aA. However, only Z4-11Al mediates courtship in experienced males, not (R)-linalool. Behavioural discrimination is reflected by calcium imaging of the antennal lobe, showing distinct glomerular activation patterns by these two compounds. Male sex pheromone cVA is known to affect male and female courtship at close range, but does not elicit upwind flight attraction as a single compound, in contrast to Z4-11Al. A blend of the food odour vinegar and cVA attracted females, while a blend of vinegar and female pheromone Z4-11Al attracted males, instead. Sex-specific upwind flight attraction to blends of food volatiles and male and female pheromone, respectively, adds a new element to Drosophila olfactory premating communication and is an unambiguous paradigm for identifying the behaviourally active components, towards a more complete concept of food-pheromone odour objects.

  • 32. Burgert, J.
    et al.
    Seemann, W.
    Lundberg, Bengt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Uppsala University.
    Recursive algorithm for the distribution of characteristic impedance of an elastic rod producing a prescribed impact force history on a given elastic rod2022In: International Journal of Impact Engineering, ISSN 0734-743X, E-ISSN 1879-3509, Vol. 161, article id 104133Article in journal (Refereed)
    Abstract [en]

    Axial impact between two elastic rods with piecewise constant characteristic impedance is considered. The distribution of characteristic impedance of the impacted rod and the impact velocity are given. By use of a 1D recursive algorithm, the characteristic impedances of the impacting rod are determined as long as they are all positive so that a prescribed impact force is realized. A condition for positivity of the characteristic impedance is derived in terms of transmission coefficients for wave energy. At the time from which positivity of all characteristic impedances cannot be maintained, or earlier, the characteristic impedance of the impacting body is continued, e.g., at the level of the last positive characteristic impedance or at level zero corresponding to cutting off the impacting rod. Examples of prescribed exponentially decreasing and linearly increasing impact forces are presented for a uniform impacted rod with constant characteristic impedance. In these examples, there is good agreement between the prescribed impact force and the impact force obtained from 3D FE simulation with a piecewise linear diameter of the impacting body that approximates the piecewise constant diameter obtained by use of the 1D recursive algorithm. 

  • 33. Chansa, Oris
    et al.
    Luo, Zhong-yang
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Yu, Chun-jiang
    Behavior of alkali minerals in oxyfuel co-combustion of biomass and coal at elevated pressure2021In: Journal of Zhejiang University: Science A, ISSN 1673-565X, Vol. 22, no 2, p. 116-129Article in journal (Refereed)
    Abstract [en]

    Combustion of biomass or coal is known to yield aerosols and condensed alkali minerals that affect boiler heat transfer performance. In this work, alkali behavior in the pressurized oxyfuel co-combustion of coal and biomass is predicted by thermodynamic and chemical kinetic calculations. Existence of solid minerals is evaluated by X-ray diffraction (XRD) analysis of ashes from pressure thermogravimetric combustion. Results indicate that a rise in pressure affects solid alkali minerals negligibly, but increases their contents in the liquid phase and decreases them in the gas phase, especially below 900 °C. Thus, less KCl will condense on the boiler heat transfer surfaces leading to reduced corrosion. Increasing the blend ratio of biomass to coal will raise the content of potassium-based minerals but reduce the sodium-based ones. The alkali-associated slagging in the boiler can be minimized by the synergistic effect of co-combustion of sulphur-rich coal and potassium-rich biomass, forming stable solid K2SO4 at typical fluidized bed combustion temperatures. Kinetics modelling based on reaction mechanisms shows that oxidation of SO2 to SO3 plays a major role in K2SO4 formation but that the contribution of this oxidation decreases with increase in pressure. 

  • 34. Cheng, W.
    et al.
    Shao, J.
    Zhu, Y.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Jiang, H.
    Hu, J.
    Zhang, X.
    Yang, H.
    Chen, H.
    Effect of oxidative torrefaction on particulate matter emission from agricultural biomass pellet combustion in comparison with non-oxidative torrefaction2022In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 189, p. 39-51Article in journal (Refereed)
    Abstract [en]

    Torrefaction could improve the fuel properties and reduce the operating costs. However, the particulate matter (PM) emission behavior during the torrefied pellet combustion remains unknown. In this work, cotton stalk was torrefied at a temperature of 220–300 °C with a O2 concentration of 0–21%. The torrefied pellet was burned out and PM emission behavior was investigated using a Dekati low-pressure impactor. The results show that oxidative torrefaction leads to notable decreases of H/C and O/C ratios, which makes the fuel properties similar to coals. The heating value is significantly improved and sensitive to the torrefaction temperature. Both non-oxidative and oxidative torrefaction give rise to considerable increase in the yield of PM10. The main composition of PM1 changed from KCl to K2SO4 due to the substantial release of Cl during torrefaction. Meanwhile, Ca and K contents in PM1-10 are generally high, implying that the presence of oxygen can facilitate the transformation of alkali and alkaline-earth metals into coarse particles. The torrefaction temperature at around 260 °C with a low O2 concentration of 0–6% are the optimal torrefaction operation conditions to produce good quality torrefied cotton stalk pellet with respect to high heating value and low PM emission in later combustion application. 

  • 35. Cheng, W.
    et al.
    Zhu, Y.
    Shao, J.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Wu, G.
    Jiang, H.
    Hu, J.
    Huang, Z.
    Yang, H.
    Chen, H.
    Mitigation of ultrafine particulate matter emission from agricultural biomass pellet combustion by the additive of phosphoric acid modified kaolin2021In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 172, p. 177-187Article in journal (Refereed)
    Abstract [en]

    The emission of ultrafine particulate matter (PM0.2) originated from the agricultural biomass pellet combustion poses great threat to atmospheric environment and human health, which restricts its large-scale utilization. In this study, a new phosphoric acid modification method is proposed to improve the PM0.2 reduction efficiency by kaolin additive. The effects of phosphoric acid concentration and treatment time on the physicochemical properties of kaolin and on the mitigation of PM0.2 emission from the pellet combustion are investigated. Results indicate that phosphoric acid modification destroy the internal structure of kaolin by the leaching of Al cations and the formation of active free silica. Meanwhile, the pore structure increases after modification with residual P deposited on the surface, which results in better alkali capture ability of modified kaolin. With the addition of phosphoric acid modified kaolin, significant reduction of PM0.2 emission can be achieved and the reduction ratio is proportional to the acid concentration. The maximum PM0.2 emission reduction ratio reaches 64.5% for the kaolin additive modified by 12 mol/L phosphoric acid for 6 hours. Finally, the PM0.2 reduction mechanism is proposed based on the analysis results, which provides technical knowhow for the industrial application of agricultural biomass pellet combustion. 

  • 36.
    Cordova, Armando
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Alimohammadzadeh, Rana
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sanhueza, Italo
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Tai, Cheuk-Wai
    Stockholm University, Stockholm.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Ibrahem, Ismail
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    A sustainable strategy for production and functionalization of nanocelluloses2019In: Pure and Applied Chemistry, ISSN 0033-4545, E-ISSN 1365-3075, Vol. 91, no 5, p. 865-874Article in journal (Refereed)
    Abstract [en]

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

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  • 37.
    Costa, Carolina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cellulose Dissolution and Amphiphilicity: Insights on the Emulsion Formation and Stabilization2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    An amphiphilic polymer is expected to adsorb at the oil-water interface and be capable of stabilizing emulsions. Cellulose derivatives, cellulose nanoparticles and regenerated cellulose particles show an intrinsic amphiphilic character by self-assembling at oil-water interfaces and stabilizing emulsions without the aid of surfactants or any other co-stabilizers. In its polymeric form, the native cellulose chains could be expected to share similar emulsifying abilities. However, cellulose dissolution is the main issue when it comes to its direct application in emulsion technology and, therefore, there is a lack of knowledge when it comes to this type of approach on making emulsions. Cellulose does not dissolve in either oil or water, but it can be dissolved in water based-solvents at extreme pH's. In this thesis, the interfacial behaviour of cellulose was studied at oil-water interfaces by having cellulose dissolved in aqueous solutions of H3PO4 (very low pH) and NaOH/NaOH-urea and TBAH (very high pH). 

    In its dissolved state, cellulose was seen to substantially decrease the interfacial tension (IFT) between the oil phase and the aqueous media, which was a consequence of the adsorption of cellulose at oil-water interfaces. The extent of the IFT reduction was shown to be dependent on the solvent quality. The optimal solvency conditions for cellulose were found for the alkaline solvent with an intermediate polarity (NaOH-urea), which is in line with the favourable conditions for adsorption of an amphiphilic polymer. However, in stabilizing oil-in-water emulsions (O/W), to achieve long-term stability and prevent oil separation from the emulsions, further reduction in cellulose's solvency was needed. This was achieved by a change in the pH of the emulsions that induced the regeneration of cellulose on the surface of the oil droplets (in-situ regeneration) in the form of a continuous film, which was revealed by cryogenic scanning electron microscopy (cryo-SEM). The topography of the droplets surface was found to be very different from what has been reported for cellulose Pickering emulsions. Upon in-situ regeneration, the rate of droplets coalescence was dramatically reduced and emulsions showed a remarkable stability against oil-separation. Finally, the combination of cellulose with lignin as an amphiphilic natural co-stabilizer was studied regarding their compatibility in solution. Lignin was found to improve cellulose dissolution in NaOH (aq.) and delay the gelation kinetics upon ageing or temperature increase in the solutions. Data suggests lignin as an amphiphilic additive able to weaken the hydrophobic interactions among cellulose molecules. 

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  • 38.
    Costa, Carolina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Medronho, Bruno
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. University of Algarve.
    Eivazi, Alireza
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Svanedal, Ida
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lindman, Björn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lignin enhances cellulose dissolution in cold alkali2021In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 274, article id 118661Article in journal (Refereed)
    Abstract [en]

    Aqueous sodium hydroxide solutions are extensively used as solvents for lignin in kraft pulping. These are also appealing systems for cellulose dissolution due to their inexpensiveness, ease to recycle and low toxicity. Cellulose dissolution occurs in a narrow concentration region and at low temperatures. Dissolution is often incomplete but additives, such as zinc oxide or urea, have been found to significantly improve cellulose dissolution. In this work, lignin was explored as a possible beneficial additive for cellulose dissolution. Lignin was found to improve cellulose dissolution in cold alkali, extending the NaOH concentration range to lower values. The regenerated cellulose material from the NaOH-lignin solvents was found to have a lower crystallinity and crystallite size than the samples prepared in the neat NaOH and NaOH-urea solvents. Beneficial lignin-cellulose interactions in solution state appear to be preserved under coagulation and regeneration, reducing the tendency of crystallization of cellulose. 

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  • 39.
    Costa, Carolina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Medronho, Bruno
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. University of Algarve, Faro, Portugal.
    Filipe, Alexandra
    University of Algarve, Faro, Portugal.
    Mira, Isabel
    RISE, Stockholm.
    Lindman, Björn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Emulsion formation and stabilization by biomolecules: The leading role of cellulose2019In: Polymers, E-ISSN 2073-4360, Vol. 11, no 10, article id 1570Article in journal (Refereed)
    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). 

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  • 40.
    Costa, Carolina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Medronho, Bruno
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. University of Algarve, Campus de Gambelas, Ed. 8, 8005-139 Faro, Portugal .
    Filipe, Alexandra
    University of Algarve, Campus de Gambelas, Ed. 8, 8005-139 Faro, Portugal.
    Romano, Anabela
    University of Algarve, Campus de Gambelas, Ed. 8, 8005-139 Faro, Portugal.
    Lindman, Björn
    University of Lund; University of Coimbra, Rua Larga, 3004- 535 Coimbra, Portugal .
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    On the formation and stability of cellulose-based emulsions in alkaline systems: Effect of the solvent quality2022In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 286, article id 119257Article in journal (Refereed)
    Abstract [en]

    With amphiphilic properties, cellulose molecules are expected to adsorb at the O/W interface and be capable of stabilizing emulsions. The effect of solvent quality on the formation and stability of cellulose-based O/W emulsions was evaluated in different alkaline systems: NaOH, NaOH-urea and tetrabutylammonium hydroxide (TBAH). The optimal solvency conditions for cellulose adsorption at the O/W interface were found for the alkaline solvent with an intermediate polarity (NaOH-urea), which is in line with the favorable conditions for adsorption of an amphiphilic polymer. A very good solvency (in TBAH) and the interfacial activity of the cation lead to lack of stability because of low cellulose adsorption. However, to achieve long-term stability and prevent oil separation in NaOH-urea systems, further reduction in cellulose's solvency was needed, which was achieved by a change in the pH of the emulsions, inducing the regeneration of cellulose at the surface of the oil droplets (in-situ regeneration).

  • 41.
    Costa, Carolina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Mira, Isabel
    RISE, Stockholm.
    Benjamins, Jan-Willem
    RISE, Stockholm.
    Lindman, Björn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Interfacial activity and emulsion stabilization of dissolved cellulose2019In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 292, article id 111325Article in journal (Refereed)
    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. 

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  • 42.
    Costa, Carolina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Rosa, Pedro
    Filipe, Alexandra
    Medronho, Bruno
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. University of Algarve.
    Romano, Anabela
    Liberman, Lucy
    Talmon, Yeshayahu
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cellulose-stabilized oil-in-water emulsions: Structural features, microrheology, and stability2021In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 252, article id 117092Article in journal (Refereed)
    Abstract [en]

    Cellulose-based oil-in-water (O/W) emulsions were studied by diffusing wave spectroscopy (DWS) regarding the effect of the cellulose concentration and mixing rate on the average droplet size, microrheological features and stability. Furthermore, the microstructure of these emulsions was imaged by cryo-scanning electron microscopy (cryo-SEM). The micrographs showed that cellulose was effectively adsorbed at the oil-water interface, resembling a film-like shell that protected the oil droplets from coalescing. The non-adsorbed cellulose that was observed in the continuous aqueous medium, contributed to the enhancement of the viscosity of the medium, leading to an improvement in the stability of the overall system. Generally, the higher the cellulose concentration and mixing rate, the smaller the emulsion droplets formed, and the higher was their stability. The combination of both techniques, DWS and cryo-SEM, revealed a very appealing and robust methodology for the characterization and design of novel emulsion-based formulations. 

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  • 43. Dahal, Roshi
    et al.
    Uusi-Kyyny, Petri
    Pokki, Juha- Pekka
    Alopaeus, Ville
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Aalto University, Finland.
    Liquid – liquid equilibria in binary and ternary systems of phenol + hydrocarbons (n–dodecane or n–hexadecane) and water + phenol + hydrocarbons (n–dodecane or n–hexadecane) at temperatures between 298K and 353K2022In: Fluid Phase Equilibria, ISSN 0378-3812, E-ISSN 1879-0224, Vol. 556, article id 113402Article in journal (Refereed)
    Abstract [en]

    This study reports liquid–liquid equilibrium (LLE) and liquid–liquid–liquid equilibrium (LLLE) data for binary (phenol + n-dodecane, or n-hexadecane) and ternary (water + phenol + n-dodecane, or n-hexadecane) systems measured under atmospheric pressure. The compositions of coexisting phases were determined with analytical and cloud point methods at temperatures 298 K – 353 K. The Non–Random Two–Liquid (NRTL) excess Gibbs energy model was employed to correlate the measured systems. The binary interaction parameters were regressed using analytical LLE and cloud point data. In addition, the parameters were also calculated using the binary LLE data combined with the isothermal vapor–liquid data from the literature applying the NRTL–RK (Redlich–Kwong) property method. The average absolute deviations in liquid mole fraction obtained with the NRTL model (using six adjusted parameters) for the LLE and VLE experimental data were 0.006 and 0.014 respectively. The phase equilibria of binary phenol + hydrocarbon (n-dodecane or n-hexadecane) systems were modeled at the temperature range of 313 K – 573 K. 

  • 44.
    Dahal, Roshi
    et al.
    Aalto University, Finland.
    Uusi-Kyyny, Petri
    Aalto University, Finland.
    Pokki, Juha-Pekka
    Aalto University, Finland.
    Alopaeus, Ville
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Aalto University, Finland.
    Vapor- liquid equilibrium for the n-dodecane + phenol and n-hexadecane + phenol systems at 523 K and 573 K2021In: Fluid Phase Equilibria, ISSN 0378-3812, E-ISSN 1879-0224, Vol. 537, article id 112991Article in journal (Refereed)
    Abstract [en]

    A continuous flow apparatus was applied to measure the phase equilibrium at 523 K and 573 K. The performance of the apparatus was analysed with the determination of vapor pressures of water at the temperatures (T = 453 K and 473 K). The measured water vapor pressures deviated from the literature values less than 1 %. Vapor pressures of n-dodecane, n-hexadecane and phenol were measured at the temperatures (T = 523–623 K) and, the bubble point pressures of n-dodecane + phenol and n-hexadecane + phenol were measured at the temperatures (T = 523 K and 573 K). The measured vapor pressures of the pure components were compared with the literature values. Relative vapor pressure deviated from the literature value less than 2 % for all the measured vapor pressures. The measured vapor pressures value in this work agreed well with the literature, which indicates that the measurement apparatus and the method can produce good-quality data. The measured bubble point pressures for the n-dodecane + phenol and n-hexadecane + phenol systems were modeled with Peng-Robinson and Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) equations of state and Non-random Two-liquid (NRTL) activity coefficient model. The measured systems were at first modeled with Peng-Robinson and Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) equations of state without binary interaction parameters. Additionally, the parameters were regressed to optimize the performance of the models. The NRTL activity coefficient model described the behaviour of the measured and the literature data better than the equations of state. Furthermore, the Peng-Robinson equation of state resulted in better predictions than PC-SAFT equation of state even without binary interaction parameters regression. Both equations of state modeled the phase equilibrium behaviour of the system well. The n-dodecane + phenol system showed azeotropic behaviour. 

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  • 45.
    Dahlbom, Roland
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Off grid eller energiplushus.: Är det möjligt att gå off grid?2020Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The main target of this examination has been to see if the real estate Orkestern 1 has the possibility to go off-grid and if it is economical defendable or if on-grid solution is a better way to go. The prerequisites are good with a large roof to place solar panels to the east and west, a yearly average windspeed at 4 m/s and a low energy consumption because the house is new built and well insulated.

    To calculate how much energy that must be produced in form of heat and electricity with solar cells, windmills, pellet stove and diesel generator an energy balance and an energy distribution will be prepared with help of calculations of transmission and ventilation loses.

    Storage of energy will be done in form of pellets, battery and biodiesel. The simulation program for solar panels Polysun is used to calculate the produced solar energy for each month on the year. Diagram is prepared for each month to see the need of energy and how much every energy producer is delivering. A straight pay-off calculation is done to see if there are any economic benefits and to compare between off-grid and on-grid systems. The result will be that on-grid system is better economical but still the off-grid system is doable.

     

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  • 46.
    Dahlström, Christina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    López Durán, V.
    KTH, Stockholm.
    Keene, S. T.
    Stanford University, Stanford, CA, United States.
    Salleo, A.
    Stanford University, Stanford, CA, United States.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Wågberg, L.
    KTH, Stockholm.
    Ion conductivity through TEMPO-mediated oxidated and periodate oxidated cellulose membranes2020In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 233, article id 115829Article in journal (Refereed)
    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

  • 47.
    Ding, Bao-Jian
    et al.
    Lund Univ, Dept Biol, Solvegatan 37, SE-22362 Lund, Sweden..
    Xia, Yi-Han
    Lund Univ, Dept Biol, Solvegatan 37, SE-22362 Lund, Sweden..
    Wang, Hong-Lei
    Lund Univ, Dept Biol, Solvegatan 37, SE-22362 Lund, Sweden..
    Andersson, Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Gross, Juergen
    Julius Kuhn Inst, Inst Plant Protect Fruit Crops & Viticulture, Fed Res Ctr Cultivated Plants, Dossenheim, Germany..
    Lofstedt, Christer
    Lund Univ, Dept Biol, Solvegatan 37, SE-22362 Lund, Sweden..
    Biosynthesis of the Sex Pheromone Component (E,Z)-7,9-Dodecadienyl Acetate in the European Grapevine Moth, Lobesia botrana, Involving increment 11 Desaturation and an Elusive increment 7 Desaturase2021In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 47, no 3, p. 248-264Article in journal (Refereed)
    Abstract [en]

    The European grapevine moth, Lobesia botrana, uses (E,Z)-7,9-dodecadienyl acetate as its major sex pheromone component. Through in vivo labeling experiments we demonstrated that the doubly unsaturated pheromone component is produced by increment 11 desaturation of tetradecanoic acid, followed by chain shortening of (Z)-11-tetradecenoic acid to (Z)-9-dodecenoic acid, and subsequently introduction of the second double bond by an unknown increment 7 desaturase, before final reduction and acetylation. By sequencing and analyzing the transcriptome of female pheromone glands of L. botrana, we obtained 41 candidate genes that may be involved in sex pheromone production, including the genes encoding 17 fatty acyl desaturases, 13 fatty acyl reductases, 1 fatty acid synthase, 3 acyl-CoA oxidases, 1 acetyl-CoA carboxylase, 4 fatty acid transport proteins and 2 acyl-CoA binding proteins. A functional assay of desaturase and acyl-CoA oxidase gene candidates in yeast and insect cell (Sf9) heterologous expression systems revealed that Lbo_PPTQ encodes a increment 11 desaturase producing (Z)-11-tetradecenoic acid from tetradecanoic acid. Further, Lbo_31670 and Lbo_49602 encode two acyl-CoA oxidases that may produce (Z)-9-dodecenoic acid by chain shortening (Z)-11-tetradecenoic acid. The gene encoding the enzyme introducing the E7 double bond into (Z)-9-dodecenoic acid remains elusive even though we assayed 17 candidate desaturases in the two heterologous systems.

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  • 48. Ding, C.
    et al.
    Zhang, Z. -W
    Wang, L. -Y
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Yu, C. -J
    The research on anaerobic digestion conditions of biomethanation using low-temperature pyrolysis oil2021In: Zhongguo Huanjing Kexue/China Environmental Science, ISSN 1000-6923, Vol. 41, no 8, p. 3676-3683Article in journal (Refereed)
    Abstract [en]

    This article focused on the research of anaerobic digestion conditions using low-temperature pyrolysis oil, including the fresh inoculum acclimatization, the operation conditions of pyrolysis oil (PO) digestion and the influence of biomass pyrolysis parameters. The coupling process was studied by controlling different pyrolysis parameters and anaerobic digestion parameters. It can be concluded that the fresh sludge inoculum acclimatization can significantly improve the tolerance to the inhibitors contained in the PO, thus, the methane production from the PO digestion to a great degree. The mesophilic condition was favorable to the biooil biomethanation for the low POs under 4% as used in the experiment, whereas the thermophilic condition was favorable for the high PO concentration of 10%. Besides, more methane production can be given by 0.85mm biomass particle size, 300℃ pyrolysis temperature in the downstream step of PO digestion. 

  • 49. Duarte, H.
    et al.
    Gomes, V.
    Aliaño-González, M. J.
    Faleiro, L.
    Romano, A.
    Medronho, Bruno
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Universidade do Algarve.
    Ultrasound-Assisted Extraction of Polyphenols from Maritime Pine Residues with Deep Eutectic Solvents2022In: Foods, E-ISSN 2304-8158, Vol. 11, no 23, article id 3754Article in journal (Refereed)
    Abstract [en]

    Deep eutectic solvents represent an important alternative in the field of green solvents due to their low volatility, non-toxicity, and low synthesis cost. In the present investigation, we propose the production of enriched polyphenolic extracts from maritime pine forest residues via an ultrasound-assisted approach. A Box–Behnken experimental design with a response surface methodology was used with six variables to be optimized: solid-to-solvent ratio, water percentage, temperature and time of extraction, amplitude, and catalyst concentration. The mixture of levulinic and formic acids achieved the highest extraction yield of polyphenols from pine needle and bark biomass. In addition, the solid-to-solvent ratio was found to be the only influential variable in the extraction (p-value: 0.0000). The optimal conditions were established as: 0.1 g of sample in 10 mL of LA:FA (70:30%, v/v) with 0% water and 0 M H2SO4 heated to 30 °C and extracted during 40 min with an ultrasound amplitude of 80% at 37 kHz. The bioactive properties of polyphenol-enriched extracts have been proven with significant antioxidant (45.90 ± 2.10 and 66.96 ± 2.75 mg Trolox equivalents/g dw) and antimicrobial activities. The possibility to recycle and reuse the solvent was also demonstrated; levulinic acid was successfully recovered from the extracts and reused in novel extractions on pine residues. This research shows an important alternative to obtaining polyphenol-enriched extracts from forest residues that are commonly discarded without any clear application, thus opening an important window toward the valorization of such residues. 

  • 50.
    Dunborg, Robin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Är lågtempererade värmesystem bättre lämpade för solfångare än högtempererade: Och hur mycket?2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna studie undersöker om lågtempererade värmesystem kan öka andelen solenergi i våra värmesystem. Vid studien saknades det ett referenshus vilket innebar att ett hus behövde modelleras och en energianvändning behöver simuleras fram. Modelleringen och energianvändningen simulerades i programvaran IDA ICE.

    Efter att en byggnad simulerades behövdes litteraturstudie utföras för att hitta den faktorer som begränsar den högsta möjliga uppnåbara temperaturen att tillföra våra värmesystem. Studien visade att solfångarens teoretiska stagnationstemperatur alternativt tillverkarens deklarerade stagnationstemperatur är den enda kända begränsningen utöver storleken på strålningseffekten från solen.

    För att göra bedömningen av stagnationstemperaturen utfördes flera simuleringar i programvaran MATLAB under ett normalår med data från Sveby som grundar sig i data från SMHI.

    När simuleringen av stagnationstemperaturen utfördes togs även ett annat värde fram som i studien kallas energiprofil. Den energiprofilen visar differensen mellan husets termiska effektbehov och solfångarnas producerade effekt. Med hjälp av den kan det avgöra om solfångarna under en längre tid producerar ett överskott tillräckligt för en långsiktig lagring i borrhål eller om det ska lagras kortsiktigt i ackumulatortankar.

    Det simulerades även fram hur mycket solfångarna idealt kunde producera ner på timnivå men presenterades ackumulerat på månads-nivå.

    Resultatet blev inte förvånande och där de kunde bekräftas att golvvärmen och dess systemtemperatur gav upphov till en marginellt större andel solenergi i värmesystemet mot ett radiatorsystem. Vilket kunde tidigt utläsas i verkningsgrad-diagrammet för vakuum-solfångare.

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