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  • 151. Arfvidsson, J.
    et al.
    Lindgren, Owe
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Wiberg, P.
    Luleå tekniska universitet.
    The development of a moisure sorption model to predict moisture within solid wood based on non-destructive moisture gradient measurements using CT-scanning and digital ...1997Ingår i: International Conference on Wood-Water Relations, 16 - 17 June 1997, Copenhagen, Denmark: [COST Action E8, Mechanical Performance of Wood and Wood Products] / [ed] Preben Hoffmeyer, Copenhagen: Technical University of Denmark , 1997Konferensbidrag (Refereegranskat)
  • 152.
    Ariyanto, T.
    et al.
    Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada.
    Cahyono, R. B.
    Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada.
    Vente, A.
    Environmental Science for Sustainable Energy and Technology, Avans Hogeschool.
    Mattheij, S.
    Department of Food and Agricultural Product Technology, Universitas Gadjah Mada.
    Millati, R.
    Department of Food and Agricultural Product Technology, Universitas Gadjah Mada.
    Sarto,
    Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Syamsiah, S.
    Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada.
    Utilization of fruit waste as biogas plant feed and its superiority compared to landfill2017Ingår i: International Journal of Technology, ISSN 2086-9614, Vol. 8, nr 8, s. 1385-1392Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fruit waste is a part of municipal solid waste which is typically disposed of directly to a landfill site. In order to utilize this valuable renewable resource, anaerobic biological processes can be employed to convert fruit waste to biogas. This usable gas is then used to generate electricity. This paper describes a comprehensive study to set up technology for converting fruit waste to electricity via biogas production. First, the fruit waste characteristics (type and composition) were systematically evaluated, and then laboratory experiments for biogas conversion to explore gas production from the waste were carried out. The biogas plant was then designed, based on the information obtained. Finally, a comparison of biogas plant with landfill was performed using life cycle assessment (LCA) to determine environmental impacts, and economic evaluation to assess daily processing costs. The results from waste characterization in one of the biggest fruit markets in Indonesia showed that the three main component fruit types were orange (64%), mango (25%), and apple (5%). Rotten fruit contributes up to 80% of the total waste in the fruit market. Based on the experimental work, the potential gas production in the biogas plant was calculated to be approximately 1075 Nm3/day, comprising 54% methane, based on 10 tons per day of fruit waste. The comparison demonstrates that it is a better option to utilize fruit waste in a biogas plant, in terms of LCA and daily operational costs, than to dispose of it in landfill. 

  • 153.
    Arkstål, Emil
    Linköpings universitet, Institutionen för datavetenskap, Interaktiva och kognitiva system.
    Interactive Analytics and Visualization for Data Driven Calculation of Individualized COPD Risk2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Chronic obstructive pulmonary disease (COPD) is a high mortality disease, second to stroke and ischemic heart disease. This non-curable disease progressively exacerbates, leading to high personal and societal economic impact, reduced quality of life and often death. General treatment plans for COPD risk mistreating the individuals’ condition. To be effective, the treatment should be individualized following the practices of precision medicine. The aim of this thesis was to develop a data driven algorithm and system with visualization to assess individual COPD risk. With MRI body composition profile measurements, it is possible to accurately assess propensity of a multitude of metabolic conditions, such as coronary heart disease and type 2 diabetes.  The algorithm and system has been developed using Wolfram Language and R within the Wolfram Mathematica framework. The algorithm calculates individualized virtual control groups metabolically similar to the patient’s body composition and spirometric profile. Using UK Biobank data, our tool was used to assess patient COPD propensity using an individual-specific virtual control group with AUROC 0.778 (female) and 0.758 (men). Additionally, the tool was used to identify new body composition profiles related to COPD and associated comorbid conditions.

  • 154.
    Arnau, Laurent
    KTH, Skolan för kemivetenskap (CHE).
    Techno-Economic Feasibility Study for the Production of Microalgae Based Plant Biostimulant2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Microalgae are considered as a potential feedstock for many promising applications. Some active substances in microalgae have plant biostimulation effects potentially useful in agriculture. However, to produce such a microalgal biomass, specific microalgae cultivation and post-treatment processes must be designed to preserve active substances. A particular focus is provided on cultivation (tubular photobioreactor) and different plausible post-treatment scenarios for microalgae separation (flocculation and centrifugation) and preservation (sterilization and drying). For each step, yield and energy consumption are modeled using data taken from literature or lab and pilot scale experiments. Industrial equipment for scale-up process is also studied by comparing existing systems. These models enable to make an economic evaluation of the whole process and to study its profitability for each scenario. The breakeven price is calculated as a function of the production rate. Several parameters are suggested to improve system efficiency and profitability at the end of this study. However, a better microalgae characterization and more experiments on potential post-treatment systems are required to improve the accuracy of the model.

  • 155. Asachi, R.
    et al.
    Karimi, K.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, M.J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Fungal autolysate as a nutrient supplement for ethanol and chitosan production by Mucor indicus2011Ingår i: Biotechnology letters, ISSN 0141-5492, E-ISSN 1573-6776, Vol. 33, nr 12, s. 2405-2409Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mucor indicus can be used to produce ethanol from a variety of sugars, including pentose's. An extract of it, produced by autolysis, could replace yeast extract in culture medium with improved production of ethanol. At 10 g l(-1), the extract gave a higher ethanol yield (0.47 g g(-1)) and productivity (0.71 g l(-1) h(-1)) compared to medium containing yeast extract (yield 0.45 g g(-1); productivity 0.67 g l(-1) h(-1)).

  • 156.
    Asadollahzadeh, Mohammadtaghi
    et al.
    Department of Pulp and Paper Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
    Ghasemian, Ali
    Department of Pulp and Paper Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
    Saraeian, Ahmadreza
    Department of Pulp and Paper Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
    Resalati, Hossein
    Department of Wood and Paper Sciences, Sari University of Agricultural Sciences and Natural Resources, Sari, Iran.
    Lennartsson, Patrik R.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Using spent sulfite liquor for valuable fungal biomass production by Aspergilus oryzae2017Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, nr 4, s. 630-638Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The recent and increasing interest in bioconversion of lignocellulosic wastes into value-added products has led to extensive research on various microorganisms and substrates. In this study, filamentous fungus Aspergillus oryzae was cultivated on spent sulfite liquor (SSL) from a pulp mill. The process using an airlift bioreactor (3.5 L working volume) was successfully carried out in 48 h with an airflow of 0.85 vvm (volume air per volume culture per minute) at 35°C and pH 5.5. The cultivation results showed that the fungal biomass concentration was higher in more diluted SSL. The highest and lowest fungal biomass concentrations when spore inoculation was used were 10.2 and 6.5 g/l SSL, in diluted SSL to 60 and 80%, respectively. The range of crude protein and total fat of the fungal biomass was 0.44 – 0.48 and 0.04 – 0.11 g/g biomass dry weight, respectively. All essential amino acids were present in acceptable quantities in the fungal biomass. The results obtained in this study have practical implications in that the fungus A. oryzae could be used successfully to produce fungal biomass protein using spent sulfite liquor for animal feed.

  • 157. Asadollahzadeh, Mohammadtaghi
    et al.
    Ghasemian, Ali
    Saraeian, Ahmadreza
    Resalati, Hossein
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Production of Fungal Biomass Protein by Filamentous Fungi Cultivation on Liquid Waste Streams from Pulping Process2018Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 13, nr 3, s. 5013-5031Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was to convert the spent liquors obtained from acidic sulfite and neutral sulfite semi-chemical (NSSC) pulping processes into protein-rich fungal biomass. Three filamentous fungi, Aspergillus oryzae, Mucor indicus, and Rhizopus oryzae, were cultivated on the diluted spent liquors in an airlift bioreactor with airflow of 0.85 vvm at 35 degrees C and pH 5.5. Maximum values of 10.17 g, 6.14 g, and 5.47 g of biomass per liter of spent liquor were achieved in the cultivation of A. oryzae, M. indicus, and R. oryzae on the spent sulfite liquor (SSL) diluted to 60%, respectively, while A. oryzae cultivation on the spent NSSC liquor (SNL) diluted to 50% resulted in the production of 3.27 g biomass per liter SNL. The fungal biomasses contained 407 g to 477 g of protein, 31 g to 114 g of fat, 56 g to 89 g of ash, and 297 g to 384 g of alkali-insoluble material (AIM) per kg of dry biomass. The amino acids, fatty acids, and mineral elements composition of the fungal biomasses corresponded to the composition of commercial protein sources especially soybean meal. Among the fungi examined, A. oryzae showed better performance to produce protein-rich fungal biomass during cultivation in the spent liquors.

  • 158.
    Ask, Per
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik. Linköpings universitet, Tekniska högskolan.
    EDWALL, G
    Tibbling, Lita
    ESOPHAGEAL PH MEASUREMENTS USING AN ANTIMONY ELECTRODE1980Ingår i: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 18, nr 1Artikel i tidskrift (Refereegranskat)
  • 159.
    Ask, Per
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik. Linköpings universitet, Tekniska högskolan.
    Öberg, Åke
    Linköpings universitet, Institutionen för medicinsk teknik.
    Tibbling, Lita
    ESOPHAGEAL MANOMETRY - DETERMINATION OF BANDWIDTH REQUIREMENTS BY SIGNAL ANALYSIS1980Ingår i: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 25, nr 5Artikel i tidskrift (Refereegranskat)
  • 160.
    Aski, Abolfazl Lotfi
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Borghei, Alimohammad
    Department of Biosystem Mechanical Engineering, Islamic Azad University Tehran Science and Research Branch.
    Zenouzi, Ali
    Iranian Research Organizations for Science and Technology (IROST).
    Ashrafi, Nariman
    Department of Mechanical and Aerospace Engineering, Islamic Azad University Tehran Science and Research Branch.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Effect of Steam Explosion on the Structural Modification of Rice Straw for Enhanced Biodegradation and Biogas Production2019Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, nr 1, s. 464-485Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The goal of this study was to develop an operational steam explosion pretreatment for effective modification of rice straw chemical structure in order to improve its biodegradability and methane yield. The parameters of pressure (5 bar to 15 bar), moisture (0% to 70%), and time (1 min to 15 min) were studied in steam explosion pretreatment. The steam explosion efficiency was investigated according to the changes in crystallinity structure and chemical composition on rice straw, as well as the methane yield from straw. Steam explosion changed the structure linkages between the lignin and carbohydrate, which was indicated by a reduction in the peak intensities in the bonds from 1648 cm(-1) to 1516 cm(-1). After pretreatment, the crystallinity index of the rice straw in the 10 bar-10 min cycle with no moisture and 15 bar-10 min cycle with 70% moisture increased from 22.9% to 28.3% and 28.6%, respectively. Steam explosion efficiently decreased the lignin. The highest reduction in the amount of lignin was observed with the 10 bar-10 min cycle, which reached from 18.6% to 13.0%. The methane yield increased with the cycles 10 bar-10 min and 15 bar-15 min with 35% moisture, and 15 bar-10 min with 70% moisture by 113%, 104%, and 147% compared to that of the untreated straw, respectively. Moreover, the highest biodegradation percent of the rice straw was obtained in these cycles.

  • 161.
    Aslanzadeh, S.
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Rajendran, K.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, M.J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    A comparative study between single- and two-stage anaerobic digestion processes: Effects of organic loading rate and hydraulic retention time2014Ingår i: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 95, s. 181-188Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of an organic loading rate (OLR) and a hydraulic retention time (HRT) was evaluated by comparing the single-stage and two-stage anaerobic digestion processes. Wastes from the food processing industry (FPW) and the organic fraction of the municipal solid waste (OFMSW) were used as substrates. The OLR was increased at each step from 2 gVS/l/d to 14 gVS/l/d, and the HRT was decreased from 10 days to 3 days. The highest theoretical methane yield achieved in the single-stage process was about 84% for the FPW during an OLR of 3 gVS/l/d at a HRT of 7 days and 67% for the OFMSW at an OLR of 2 gVS/l/d and a HRT of 10 days. The single-stage process could not handle a further increase in the OLR and a decrease in the HRT; thus, the process was stopped. A more stable operation was observed at higher OLRs and lower HRTs in the two-stage system. The OLR could be increased to 8 gVS/l/d for the FPW and to 12 gVS/l/d for the OFMSW, operating at a HRT of 3 days. The results show a conclusion of 26% and 65% less reactor volume for the two-stage process compared to the single-stage process for the FPW and the OFMSW, respectively.

  • 162.
    Aslanzadeh, Solmaz
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Pretreatment of cellulosic waste and high rate biogas production2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The application of anaerobic digestion technology is growing worldwide, mainly because of its environmental benefits. Nevertheless, anaerobic degradation is a rather slow and sensitive process. One of the reasons is the recalcitrance nature of certain fractions of the substrate (e.g., lignocelluloses) used for microbial degradation; thus, the hydrolysis becomes the rate-limiting step. The other reason is that the degradation of organic matter is based on a highly dynamic, multi-step process of physicochemical and biochemical reactions. The reactions take place in a sequential and parallel way under symbiotic interrelation of a variety of anaerobic microorganisms, which all together make the process sensitive. The first stage of the decomposition of the organic matter is performed by fast growing (hydrolytic and acid forming) microorganisms, while in the second stage the organic acids produced are metabolized by the slow growing methanogens, which are more sensitive than the acidogens; thus, methanogenesis becomes the rate-limiting step. The first part of this work evaluates the effects of a pretreatment using an organic solvent, N-methylmorpholine-N-oxide (NMMO), on cellulose-based materials in order to overcome the challenge of biomass recalcitrance and to increase the rate of the hydrolysis. NMMO-pretreatment of straw separated from the cattle and horse manure resulted in increased methane yields, by 53% and 51%, respectively, in batch digestion tests. The same kind of pretreatment of the forest residues led to an increase by 141% in the methane production during the following batch digestion assays. The second part of this work evaluates the efficacy of a two-stage process to overcome the second challenge with methanogenesis as the rate-limiting step, by using CSTR (continuous stirred tank reactors) and UASB (up flow anaerobic sludge blanket) on a wide variety of different waste fractions in order to decrease the time needed for the digestion process. In the two-stage semi-continuous process, the NMMO-pretreatment of jeans increased the biogas yield due to a more efficient hydrolysis compared to that of the untreated jeans. The results indicated that a higher organic loading rate (OLR) and a lower retention time could be achieved if the material was easily degradable. Comparing the two-stage and the single-stage process, treating the municipal solid waste (MSW) and waste from several food processing industries (FPW), showed that the OLR could be increased from 2 gVS/l/d to 10 gVS/l /d, and at the same time the HRT could be decreased from 10 to 3 days, which is a significant improvement that could be beneficial from an industrial point of view. The conventional single stage, on the other hand, could only handle an OLR of 3 gVS/l/d and HRT of 7 days.

  • 163.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Berg, Andreas
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Sárvári Horváth, Ilona
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Biogas Production from N-Methylmorpholine-N-oxide (NMMO) Pretreated Forest Residues2014Ingår i: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1559-0291, Vol. 172, nr 6, s. 2998-3008Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignocellulosic biomass represents a great potential for biogas production. However, a suitable pretreatment is needed to improve their digestibility. This study investigates the effects of an organic solvent, N-Methylmorpholine-N-oxide (NMMO) at temperatures of 120 and 90 °C, NMMO concentrations of 75 and 85 % and treatment times of 3 and 15 h on the methane yield. The long-term effects of the treatment were determined by a semicontinuous experiment. The best results were obtained using 75 % NMMO at 120 °C for 15 h, resulting in 141 % increase in the methane production. These conditions led to a decrease by 9 % and an increase by 8 % in the lignin and in the carbohydrate content, respectively. During the continuous digestion experiments, a specific biogas production rate of 92 NmL/gVS/day was achieved while the corresponding rate from the untreated sample was 53 NmL/gVS/day. The operation conditions were set at 4.4 gVS/L/day organic loading rate (OLR) and hydraulic retention time (HRT) of 20 days in both cases. NMMO pretreatment has substantially improved the digestibility of forest residues. The present study shows the possibilities of this pretreatment method; however, an economic and technical assessment of its industrial use needs to be performed in the future.

  • 164. Aslanzadeh, Solmaz
    et al.
    Ishola, Mofoluwake M.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Richards, Tobias
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    An Overview of Existing Individual Unit Operations2014Ingår i: Biorefineries: Integrated Biochemical Processes for Liquid Biofuels, Elsevier Inc. , 2014Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    BACKGROUND: Because of its extreme toxicity for microorganisms, the limonene content of citrus wastes (CWs) has been a major obstacle to the conversion of CWs to biofuels. The main objective of this study was to develop a new process for the utilization of CWs that can be economically feasible when the supply of CW is low.

    RESULTS: Steam explosion pre-treatment was applied to improve the anaerobic digestibility of CWs, resulting in a decrease of initial limonene concentration by 94.3%. A methane potential of 0.537 ± 0.001 m 3 kg -1 VS (volatile solids) was obtained during the following batch digestion of treated CWs, corresponding to an increase of 426% compared with that of the untreated samples. Long-term effects of the treatment were further investigated by a semi-continuous co-digestion process. A methane production of 0.555 ± 0.0159 m 3 CH 4 kg -1 VS day -1 was achieved when treated CWs (corresponding to 30% of the VS load) were co-digested with municipal solid waste.

    CONCLUSION: The process developed can easily be applied to an existing biogas plant. The equipment cost for this process is estimated to be one million USD when utilizing 10 000 tons CWs year -1. 8.4 L limonene and 107.4 m 3 methane can be produced per ton of fresh citrus wastes in this manner. 

  • 165.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Rajendran, Karthik
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Jeihanipour, Azam
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Waste textile processing into biogas using two-stage reactors2013Konferensbidrag (Övrigt vetenskapligt)
  • 166.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Rajendran, Karthik
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    A comparative study between conventional and two stage anaerobic process: Effect of organic loading rate and hydraulic retention time2013Ingår i: / [ed] Shu Li, Jegatheesan Veeriah, Keir Greg, Kier Merrin, Chang Chia-Yuan, CESE 2013 , 2013Konferensbidrag (Refereegranskat)
  • 167.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Rajendran, Karthik
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Pretreatment of Lignocelluloses for Biogas and Ethanol Processes2014Ingår i: Advances in Industrial Biotechnology / [ed] Ram Sarup Singh, Ashok Pandey, Christian Larroche, Asiatech Publishers Inc , 2014, s. 125-150Kapitel i bok, del av antologi (Refereegranskat)
  • 168.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Rajendran, Karthik
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Pretreatment of lignocelluloses for biogas and ethanol processes2013Ingår i: Advances in Industrial Biotechnology / [ed] Ram Sarup Singh, Ashok Pandey, Christian Larroche, I. K. International Publishing House , 2013, s. 125-150Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 169.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Sárvári Horváth, Ilona
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Pretreatment of straw fraction of manure for improved biogas production2011Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 6, nr 4, s. 5193-5205Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pretreatment of straw separated from cattle and horse manure using N-methylmorpholine oxide (NMMO) was investigated. The pretreatment conditions were for 5 h and 15 h at 120 °C, and the effects were evaluated by batch digestion assays. Untreated cattle and horse manure, both mixed with straw, resulted in 0.250 and 0.279 Nm3 CH4/kgVS (volatile solids), respectively. Pretreatment with NMMO improved both the methane yield and the degradation rate of these substrates, and the effects were further amplified with more pretreatment time. Pretreatment for 15 h resulted in an increase of methane yield by 53% and 51% for cattle and horse manure, respectively. The specific rate constant, k0, was increased from 0.041 to 0.072 (d-1) for the cattle and from 0.071 to 0.086 (d-1) for the horse manure. Analysis of the pretreated straw shows that the structural lignin content decreased by approximately 10% for both samples and the carbohydrate content increased by 13% for the straw separated from the cattle and by 9% for that separated from the horse manure. The crystallinity of straw samples analyzed by FTIR show a decrease with increased time of NMMO pretreatment.

  • 170.
    Aslanzadeh, Solmaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Sárvári Horváth, Ilona
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Pretreatment of straw fraction of manure for improved biogas production2011Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 6, nr 4, s. 5193-5205Artikel i tidskrift (Refereegranskat)
  • 171.
    Asnafi, Nader
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Proceedings of the 2nd International Conference on Material Engineering and Advanced Manufacturing Technology (MEAMT 2018)2018Proceedings (redaktörskap) (Refereegranskat)
  • 172.
    Astiani, D.
    et al.
    Faculty of Forestry, Universitas Tanjungpura.
    Curran, L. M.
    Burhanuddin,
    Faculty of Forestry, Universitas Tanjungpura.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Mujiman,
    Lembaga Landscape Livelihood Indonesia Pontianak.
    Hatta, M.
    Faculty of Forestry, Universitas Tanjungpura.
    Pamungkas, W.
    Faculty of Forestry, Universitas Tanjungpura.
    Gusmayanti, Evi
    Lembaga Landscape Livelihood Indonesia Pontianak.
    Fire-Driven Biomass And Peat Carbon Losses And Post-Fire Soil Co2 Emission In A West Kalimantan Peatland Forest2018Ingår i: Journal of Tropical Forest Science, ISSN 0128-1283, Vol. 30, nr 4, s. 570-575Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Indonesian peatland forest is considered a huge sink of tropical carbon and thereby make significant contribution to global terrestrial carbon storage. However, landcover and landuse changes in this ecosystem have incurred a synergistic exposure to drought and wildfires. Deforestation and forest degradation through combustion and decomposition of forest biomass and soil carbon have become global issues because of their greenhouse gas contribution to global climate change. Thus fire-driven carbon losses in these peatlands have increased the need to evaluate the impacts of fire at a landscape scale. In 6-10 week dry periods from January to April 2014 and in January 2015, wildfires burnt peatland forest in Kubu Raya, West Kalimantan province (Indonesian Borneo). An assessment was conducted to provide more reliable estimates of the effects of fire on aboveground and soil carbon losses and their dynamics in the coastal peatlands of the province. Carbon loss from combustion of both aboveground biomass and peat soil was substantial. Moreover, CO2 emission from soil respiration at the burnt peat surface increased 46% over the first 9 months after the fire. This study clearly showed the magnitude of fire-driven carbon loss and the scale of CO2 emission to the atmosphere arising from fire in tropical peatland forest.

  • 173.
    Astiani, D
    et al.
    Faculty of Forestry, Universitas Tanjungpura.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Gusmayanti, E
    Faculty of Agriculture, Universita Tanjungpura.
    Widiastuti, T
    Faculty of Forestry, Universitas Tanjungpura.
    Burhanuddin,
    Faculty of Forestry, Universitas Tanjungpura.
    Local knowledge on landscape sustainable-hydrological management reduces soil co2 emission, fire risk and biomass loss in west Kalimantan Peatland, Indonesia2019Ingår i: Biodiversitas, ISSN 1412-033X, E-ISSN 2085-4722, Vol. 20, nr 3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Astiani D, TaherzadehMJ, Gusmayanti E, WidiastutiT, Burhanuddin.2019. Local knowledge on landscape sustainable-hydrological management reduces soil CO2 emission, fire risk and biomass loss in West Kalimantan Peatland, Indonesia.Biodiversitas 20:725-731.Local knowledge in managing peatlands, especially in the area of peat hydrology, has been practiced through generations to manage peatlands for agriculture and small scale gardens. Farmers in West Kalimantan have developed the way to conserve water by making simple dams using soil or woody plants to hold water from the peat upstream areas on small channels or rivers. To reduce puddles during rain or tides, people make small trenches, so-called parit cacingin the middle of the larger channel. The trench cross-section size is ~30-40 cm2. This channel can maintain the peat waterlevel to the extent of the depth of the channel. These channels, at the same time, are useful, for a clear, easy land ownership border for one farmer family land. The results of COemissions assessment at various water levels on the peatland landscape demonstrate that the landscape which surrounded by the parit cacingtrenches can maintain lower CO2 emissions compared to the one that has deeper water levels. The knowledge to develop this channel has also reduced the risk of peatland fire hazard and the amount of peat biomass loss on a fire event. An assessment on the effect of water level on the loss of peat biomass when burned, reduce 30-78% loss risks if compared to water table depth of 60-80cm, which is assumed as general practices on peatland recently.The practices of the knowledge on peatlands hydrology management can reduce the risk of peatland soil CO2 emission as well as loss of peat mass through decomposition and during peat fires.

  • 174.
    Atat, Rachad
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Yaacoub, E.
    Alouini, M. -S
    Abu-Dayya, A.
    Peer-to-peer content sharing techniques for energy efficiency in wireless networks with fast channel variations2013Ingår i: Green Networking and Communications: ICT for Sustainability, CRC Press , 2013, s. 3-28Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    According to the International Telecommunication Union, information and communication technology (ICT) was emitting 0.83 GtCO2e (gigatons of carbon dioxide equivalent), contributing to around 2%-2.5% of global greenhouse gas (GHG) emissions in 2007 [1]. With the continuous growth of ICT, especially in developing countries, the GHG emissions are expected to grow at double the rate over the next 10 years [1]. The Global e-Sustainability Initiative research is estimating a 72% increase in ICT energy usage from 2007 to 2020 with around 1.43 GtCO2e emissions in 2020 [1]. In addition, the telecommunications industry is witnessing an explosive increase in data traffic especially with the introduction of wireless modems and smart phones and with the presence of more than one billion wireless subscribers today. The data traffic volume is increasing by a factor of 10 every 5 years, leading to an increase of 16%-20% in energy consumption every 5 years [2]. For instance, in India, the mobile telecom industry is considered the fastest-growing sector with 584.3 million subscribers in 2010-2011 with an annual growth rate of 49.15%. It is estimated that the energy consumption of the Indian Mobile Telecom Industry was 163 PJ (petajoules) with 52.66 million tons emissions of carbon dioxide (CO2) in 2010-2011 [3]. A user who travels a distance of 25 km using public transport such as car or train can result in 1.22 kg of CO2 emissions, compared to 0.11 kg of CO2 emissions for 1 hour of video conferencing with two laptops [4]. A talk of 2 minutes per day on the phone can produce 47 kg CO2e (equivalent) per year, with a total of 125 million tons of CO2e produced by mobile phones in 1 year [5]. 

  • 175. Awoyami, Lawrence
    Effect of borate pre-treatment on the hygroscopic and swelling properties of heat-treated wood2005Ingår i: International Wood Products Journal, ISSN 0020-3203, Vol. 17, nr 2, s. 94-98Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Based on the strong correlation between acidity and some properties of heat treated wood reported in previous studies, the effect of borate impregnation as an alkali buffering medium was investigated on the hygroscopic and swelling properties of heat-treated wood. Wood samples were impregnated with 0.1M Sodium borate solution (pH = 9.4) before they were subjected to heat treatment at 200°C for durations of 2 and 4 hours. The pre-treatment impregnation with borate salt, increased the hydrophobic and antiswelling effects of the heat treatment on wood. This suggests that the bulking effect of the borate salt is more significant than its mitigating effect on the degree of cellulose degradation during heat treatment

  • 176.
    Awoyemi, Lawrence
    Luleå tekniska universitet.
    Estimation of fibre saturation point from sorption behaviour of wood in water2005Ingår i: International Wood Products Journal, ISSN 0020-3203, Vol. 17, nr 2, s. 110-113Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The fibre saturation point of wood is of tremendous importance both to the processing and properties of the material and as a result research on the various possible ways of estimating it can hardly be overemphasized. The rates of adsorption and desorption of water by wood were measured at various moisture contents. Fibre saturation point was estimated from the adsorption terminal and the intercept of the adsorption and desorption curves. The values obtained were compared with those obtained using the Walker's method. The use of the adsorptibn-desorption intercept method gave a mean accuracy of 96.1%.

  • 177.
    Awoyemi, Lawrence
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Influence of prefreezing on the fibre saturation point, sorption and swelling properties of birch (Betula pubescens) wood2006Ingår i: International Wood Products Journal, ISSN 0020-3203, Vol. 17, nr 4, s. 225-227Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Matched samples were obtained from green birch (Betula pubescens) wood. Prefreezing was done at -20°C for 72hours. Both the prefrozen and unfrozen samples were dried and soaked in water for the determination of sorption behavior, swelling properties and fibre saturation point. Prefreezing resulted in 6.7 to 666.7% increase in rate of adsorption, 0 to 13.3% decrease in the rate of desorption, 2.2% decrease in volumetric swelling coefficient and 0.8% decrease in fibre saturation point. However only the change in the rate of water adsorption is statistically significant at 95% confidence level. Since these results were obtained from samples taken from a typical board, more results are required in order to characterise the effects of prefreezing on available stock of Birch wood

  • 178.
    Awoyemi, Lawrence
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Mechanical behaviour of birch (Betula Pubescens) wood under high temperature drying2009Ingår i: International Wood Products Journal, ISSN 0020-3203, Vol. 19, nr 1, s. 27-30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High temperature drying is employed to reduce the drying time of sawn wood. However the deterioration in mechanical properties associated with it seems to be a major limitation of its use in the seasoning of some wood species. As in conventional drying, both the modulus of elasticity and modulus of rupture increase with decreasing moisture content. High temperature drying does not seem to constitute a meaningful threat to the mechanical properties of this species and hence its use is strongly recommended. The low effect of high temperature drying on this species strongly reinforces the results of the previous studies on other species that the effect of this technique is both species and property dependent.

  • 179.
    Awoyemi, Lawrence
    Luleå tekniska universitet.
    Reversibility of dimensional changes in birch (Betula pubescens) and Scots pine (Pinus sylvestris L.) wood2004Ingår i: Taiwan Linye Kexue, ISSN 1026-4469, Vol. 19, nr 2, s. 97-101Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The reversibility of wood shrinkage through swelling of birch (Betula pubescens) and Scots pine (Pinus sylvestris L.) as a measure of their response to changing conditions of adsorption and desorption during service was determined. Virtually all dimensional changes that occurred in the form of shrinkage during drying at both conventional and high temperatures were recovered during swelling in both species. It is suggested that minor changes in the equilibrium moisture content, which commonly occur during the life span of wood, will not result in significant dimensional changes in either species except in the tangential direction of Scots pine. Significant differences between shrinkage and swelling in the tangential direction in Scots pine where swelling was greater than shrinkage implies a higher stability of Scots pine during shrinkage compared to swelling. Hence it is expected that in the tangential direction, this species will be more stable during desorption than adsorption

  • 180.
    Axelsson, Josefin
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Separate Hydrolysis and Fermentation of Pretreated Spruce2011Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Bioethanol from lignocellulose is expected to be the most likely fuel alternative in the near future. SEKAB E-Technology in Örnsköldsvik, Sweden develops the technology of the 2nd generation ethanol production; to produce ethanol from lignocellulosic raw material. The objective of this master’s thesis was to achieve a better knowledge of the potential and limitations of separate hydrolysis and fermentation (SHF) as a process concept for the 2nd generation ethanol production. The effects of enzyme concentration, temperature and pH on the glucose concentration in the enzymatic hydrolysis were investigated for pretreated spruce at 10% DM using a multiple factor design. Enzyme concentration and temperature showed significant effects on the glucose concentration, while pH had no significant effect on the concentration in the tested interval of pH 4.5-5.5. To obtain the maximum glucose concentration (46.4 g/l) for a residence time of 48 h, the optimal settings within the studied parameter window are a temperature of 45.7⁰C and enzyme concentration of 15 FPU/g substrate. However, a higher enzyme concentration would probably further increase the glucose concentration. If enzymatic hydrolysis should be performed for very short residence times, e.g. 6 h, the temperature should be 48.1⁰C to obtain maximum glucose concentration. The efficiency of the enzymes was inhibited when additional glucose was supplied to the slurry prior to enzymatic hydrolysis. It could be concluded that end product inhibition by glucose occurs and results in a distinct decrease in glucose conversion. No clear conclusions could be drawn according to different techniques for slurry and enzymes, i.e. batch and fed-batch, in the enzymatic hydrolysis process. Investigations of the fermentability of the hydrolysate revealed that the fermentation step in SHF is problematic. Inhibition of the yeast decrease the fermentation efficiency and it is therefore difficult to achieve the 4% ethanol limit. Residence time for enzymatic hydrolysis (48 h) and fermentation (24 h) need to be prolonged to achieve a sufficient SHF process. However, short processing times are a key parameter to an economically viable industrial process and to prolong the residence times should therefore not be seen as a desirable alternative. SHF as a process alternative in an industrial bioethanol plant has both potential and limitations. The main advantage is the possibility to separately optimize the process steps, especially to be able to run the enzymatic hydrolysis at an optimal temperature. Although, it is important to include all the process steps in the optimization work. The fermentation difficulties together with the end product inhibition are two limitations of the SHF process that have to be improved before SHF is a preferable alternative in a large scale bioethanol plant. 

  • 181.
    Ayan, Hilal
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Industriell bioteknologi.
    Identify synthetic polymers used in cosmetics and further test their biodegradation in aqueous setup in order to assess their impact on the environment2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Plast har många användningsområden varav kosmetiska produkter är ett av dem. I kosmetika används exempelvis naturliga ämnen, sådana som förekommer i naturen och således kan brytas ned. Sedan finns syntetiska polymerer, sådana som syntetiseras och tillverkas av människor. Det finns oerhört många varianter av syntetiska polymerer som används inom kosmetika, generellt kan de kategoriseras i två grupper; mikroplaster och vattenlösliga polymerer. Med hjälp av Naturskyddsföreningens databas som innehåller hundratals kosmetikaingredienser, söktes de komponenter som hade ”poly” i sitt namn eftersom de inte täcks av lagstiftning. Bland dessa, valdes två mest förekommande polymerer för att studeras vidare, nämligen Nylon 12-20 (mikroplast) och Acrylates C/10-30 alkyl crosspolymer (vattenlöslig). En standardiserad analysmetod OECD 301 F tillämpades för att testa deras biologiska nedbrytbarhet. Resultatet från nedbrytbarhetstestet visade att ingen av polymertyperna, trots deras åtskiljande egenskaper, är lättnedbrytbar i vattenmiljöer. I följd av resultatet från analysen genomfördes en filtreringsanalys på KTH, för att avgöra om respektive polymer går att fånga upp i olika storlekar av mikrofilter. Resultatet visade att ingen av dem fångades upp (med den utrustning som var tillgänglig på KTH). Baserat på resultaten föreslås det att lagstiftningar som innefattar mikroplaster bör redigeras och revideras på ett sådant sätt att vattenlösliga polymerer är inkluderade i framtida förbud (mot mikroplaster). Utöver detta bör mer forskning ägnas åt vattenlösliga polymerer och deras påverkan på naturen.

  • 182.
    Ayoglu, Burcu
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Affinity Proteomics. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Nilsson, Peter
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Affinity Proteomics. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Schwenk, Jochen M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Affinity Proteomics. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Multiplexed antigen bead arrays for the assessment of antibody selectivity and epitope mapping2018Ingår i: Epitope Mapping Protocols, Humana Press Inc. , 2018, s. 239-248Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    With the increasing number of binding reagents for affinity-based investigations of the human proteome, high-throughput tools for the characterization of the used reagents become essential. For the analysis of binding selectivity, bead-based antigen arrays offer a miniaturized and parallelized assay platform to meet such needs, as they enable two-dimensional multiplexing to analyze up to 384 samples against up to 500 analytes in a single round of analysis. In this chapter, we describe our protocols for the generation of multiplex bead arrays built on immobilized protein fragments, as well as biotinylated peptides. Combined together, these two versions of antigen arrays offer a versatile approach for multiplexed characterization of antibody binding selectivity, off-target interactions, as well as mapping for the amino acids of epitopes involved in antibody binding.

  • 183.
    Baby, Thomas
    et al.
    Kuriakose Gregorios College, Pampady, Kottayam, Kerala, India.
    Jose E, Tomlal
    St Berchmans College, Changanachery, Kottayam, Kerala, India.
    George, Gejo
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Varkey, Vinitha
    Kuriakose Gregorios College, Pampady, Kottayam, Kerala, India.
    Cherian, Shijo K.
    St Berchmans College, Changanachery, Kottayam, Kerala, India.
    A new approach for the shaping up of very fine and beadless UV light absorbing polycarbonate fibers by electrospinning2019Ingår i: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 80, artikel-id 106103Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An innovation will be recognized as successful only if it satisfies all phases of product development; i.e. from the specification to mass production. Therefore, a cost-effective production by keeping the best possible characteristics is vital in any Industry. Large scale production of polymer fibers with ultrafine morphology is such a challenge to in the field of nanotechnology. The idea proposed here utilizes the versatile electrospinning technology for the preparation of uniform, beadless and ultraviolet light absorbing polycarbonate (PC) nanofibers. The average diameter limits to 114 nm and that too by using most convenient and comparatively less toxic solvent mixture. This method is simple and so far, it is not reported elsewhere. For THF-DMF system a PC concentration of 17 w/v% and for DCM-DMF system a PC concentration of 15 w/v% was found to be the optimum polymer concentration. The average fiber diameter and bead density were very much influenced by the viscosity, conductivity and concentration of the solution used for electrospinning. The PC fibers (PC concentration of 15 w/v % in DCM-DMF system) with lowest average diameter of 114 nm shows excellent ultraviolet absorption, semicrystalline nature, enhanced glass transition temperature and thermal stability.

  • 184.
    Backman, Anna
    Luleå tekniska universitet.
    Interaction and adhesion at the interface between wood and paint, glue, lacquer measured with DMTA and SEM2000Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The aim of the present thesis was to study the interface between wood (Pinus sylvestis) and synthetic polymers such as glue, lacquer and paint. The weakest part of these interfaces is always the bond. The long-term properties of bonds between wood and an adherend are those which are interesting. If a good bond is achieved, the surface between wood and an adherend would be less susceptible to degradation. To achieve a good bond, the wood polymers and the adhering polymers must be compatible. The contact area between the substrate and an adherend should be as large as possible to give a high quantity of bonds. A large contact area also gives the possibility of adhesion through mechanical interlocking. The interaction between wood and glue and lacquer was studied with Dynamic Mechanical Thermal Analysis. The interaction was correlated with adhesion properties observed with Scanning Electron Microscopy (SEM) fractography. Dynamic mechanical properties of untreated wood in the tangential and radial direction was studied to have a knowledge of the wood polymers behaviour. The properties of the wood polymers was needed for evaluating the change in behaviour when wood was combined with glue and lacquer. It was shown that polymers interacting with the wood polymers experienced a higher free volume in contact with wood, thus decreasing the glass transition temperature of the synthetic polymers. This decrease was considered most probably to be due to the polymers being subjected to tensile forces developed during drying. The high level of interaction was correlated to high adhesion on the wood cell wall level. Two similar commercial polyurethane-alkyd lacquers showed interaction with wood, but a commercial polyvinyl acetate glue showed poor interaction and poor adhesion. The fracture surface between wood and paint in a 50-year-old window was studied with SEM, using backscattered electron image. The method makes it possible to analyse fracture surfaces and determine where the fracture occurrs. It could be used, as an indication of whether the weakest link in different paint/wood systems is the interface.

  • 185.
    Bagge, Joakim
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Farmakognosi.
    Chromatography of Therapeutic Peptides - Contrasting SFC and HPLC2019Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This work is a comparison of a well-established and a novel, "green" and efficient technique to separate peptides of pharmaceutical interest. An attempt is made to derive the chromatographic retention behaviour from these techniques to a number of property descriptors derived from the linear sequence of amino acids. A set of therapeutic peptides were carefully chosen to be experimentally evaluated using in silico-based descriptor calculations. A principle component analysis was performed to assess the distribution of calculated descriptors for including peptides with variable properties. A diluent optimization study was also included to find the optimal diluent for peptides with minimal diluent effects and peak splitting phenomena. The results showed that the solvents tert-butanol and methanol performed best between 20-30 and 50 volumetric percent water as additive in SFC and HPLC, respectively. These diluents were then used for the peptides within the set to evaluate the retention and selectivity in HPLC and SFC. SFC performed well in terms of resolving power. Inparticular, SFC was able to separate Leuprolide and Triptorelin while HPLC was not. A comparison was also made in between the two stationary phases CN and XT, where a global selectivity was shown to be higher for CN.

    This work does also assess a novel method for determining solubility of analytes in supercritical fluid. The method was evaluated using the pharmaceutical compounds caffeine and aspirin and then used to determine solubility of Leu-Enkephalin in 20% (v/v%) methanol. The solubility of caffeine was determined to be 0.45 mg ml-1 in pure SF-CO2 under 140 bar pressure and 3.9 mg ml-1 for aspirin in 2.4% methanol. Both values correlated well with measurements from four acknowledged papers within this field. Leu-Enkephalin was found to have a solubility of 1.90 mg ml-1 using a solvent corresponding to the initial phase condition of the gradient used for peptide analysis in SFC. Further experimental work is required before the method can be implemented as a useful tool in preparative chromatography, however the results presented here show the compatibility of assessing biomolecules in both pure SF-CO2 and mixed with modifier. The possibility to determine solubility with additional modifier infers an important step of including and evaluating these compounds creating a solid support to subsequent large scale separation.

  • 186.
    Bagge, Joakim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Hedman, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Smedsrud, Sabina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Svärdström, Cornelia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Söderberg, Elisabeth
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Valdés, Fernando
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Utveckling av metodik för påvisning och typning av Listeria i livsmedelskedjan2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
  • 187.
    Baillif, Marie Le
    et al.
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Oksman, Kristiina
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    The effect of processing on fiber dispersion, fiber length and thermal degradation of bleached sulfite cellulose fiber polypropylene composites2009Ingår i: Journal of Thermoplastic Composite Materials, ISSN 0892-7057, E-ISSN 1530-7980, Vol. 22, nr 2, s. 115-133Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The goal of this study was to examine how the extrusion process affects the dispersion, length and thermal degradation of cellulose fibers (CF) in polypropylene (PP) composites. Bleached sulfite cellulose fibers were pelletized and then compounded (20 and 30 wt%) in a co-rotating twin screw extruder. The pelletizing process of cellulose fibers was found to cause extensive fiber breakage. The fiber length was decreased from an initial 1.7 to 0.8 mm. The results showed that higher screw speed, higher fiber content and two extrusions increased the shear energy, resulting in improved fiber dispersion but also caused fiber breakage and thermal degradation. The composites mechanical properties were not improved with better fiber dispersion and the reason for this might be the extensive fiber breakage and thermal degradation. Moreover, it was found that the PP polymer was also slightly degraded during the compounding process.

  • 188.
    Bajhaiya, Amit K.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Univ Manchester, Fac Life Sci, Michael Smith Bldg,Oxford Rd, Manchester M13 9PT, Lancs, England.
    Moreira, Javiera Ziehe
    Pittman, Jon K.
    Transcriptional Engineering of Microalgae: Prospects for High-Value Chemicals2017Ingår i: Trends in Biotechnology, ISSN 0167-7799, E-ISSN 1879-3096, Vol. 35, nr 2, s. 95-99Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Microalgae are diverse microorganisms that are of interest as novel sources of metabolites for various industrial, nutritional, and pharmaceutical applications. Recent studies have demonstrated transcriptional engineering of some metabolic pathways. We propose here that transcriptional engineering could be a viable means to manipulate the biosynthesis of specific high-value metabolic products.

  • 189.
    Bajraktari, Agron
    et al.
    Prishtina University, Faculty of Technical Applied Sciences.
    Korkut, Süleyman
    Duzce University, Faculty of Forestry, Department of Forest Industrial Engineering.
    Elustondo, Diego
    Duzce University, Faculty of Forestry, Department of Forest Industrial Engineering.
    Cukaj, Kushtrim
    Prishtina University, Faculty of Technical Applied Sciences.
    Thac, Bashkim
    Prishtina University, Faculty of Technical Applied Sciences.
    Weathering protection for beech wood in Kosovo2013Ingår i: International Journal of Current Engineering and Technology, ISSN 2277-4106, Vol. 3, nr 2, s. 331-333Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Beech wood (Fagus sylvatica L.) is one of the most important timber species produced in Kosovo. About 33% of the trees in our country are beech and most of the wood products are from this kind of timber. The color difference between red heart wood and white wood of the beech is significant. Adequate protection against weathering (snow, rain and low temperature) and leaching of preservative components into the environment are the main problems faced by wood companies in Kosovo as coatings defects may become apparent after only one year of outside exposure. The aim of this study was to assess the best way to protect beech wood products from weathering with available types of commercial wood coatings: film forming, non film forming, transparent stain and semi transparent penetrating stain. We concluded that the film forming and semitransparent penetrating stain are the best painting methods for beech woodproducts protection, according to weathering performance and coating properties.

  • 190. Balzani, D.
    et al.
    Holzapfel, Gerhard
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik. Graz University of Technology, Institute of Biomechanics, Center of Biomedical Engineering.
    Brinkhues, S.
    Modeling of damage in soft biological tissues and application to arterial walls2011Ingår i: Computational Plasticity XI - Fundamentals and Applications, 2011, s. 764-775Konferensbidrag (Refereegranskat)
    Abstract [en]

    A new material model is proposed for the description of stress-softening observed in cyclic tension tests performed on soft biological tissues. The modeling framework is based on the concept of internal variables introducing a scalar-valued variable for the representation of fiber damage. Remanent strains in fiber direction can be represented as a result of microscopic damage of the fiber crosslinks. Particular internal variables are defined able to capture the nature of soft biological tissues that no damage occurs in the physiological loading domain. A specific model is adjusted to experimental data taking into account the supra-physiological loading regime. For the description of the physiological domain polyconvex functions are used which also take into account fiber dispersion in a phenomenological approach. The applicability of the model in numerical simulations is shown by a representative example where the damage distribution in an arterial cross-section is analyzed.

  • 191.
    Bandmann, Nina
    KTH, Skolan för bioteknologi (BIO).
    Rational and combinatorial genetic engineering approaches for improved recombinant protein production and purification2007Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The bacterium Escherichia coli (E. coli) is in many situations an ideal host for production of recombinant proteins, since it generally provides a rapid and economical means to achieve sufficiently high product quantities. However, there are several factors that may limit this host’s ability to produce large amounts of heterologous proteins in a soluble and native form. For many applications a high purity of the recombinant protein is demanded, which implies a purification strategy where the product efficiently can be isolated from the complex milieu of host cell contaminants. In this thesis, different strategies based on both rational and combinatorial genetic engineering principles have been investigated, aiming at improving and facilitating recombinant E. coli protein production and purification.

    One objective was to improve the PEG/salt aqueous two-phase system (ATPS) purification process of the lipase cutinase, by increasing the selectivity of the protein for the system top-phase. Peptide tags, with varying properties, were designed and genetically fused to the C-terminal end of ZZ-cutinase. Greatly increased partitioning values were observed for purified protein variants fused to tryptophan containing peptide tags, particularly a (WP)4 peptide. The partitioning properties of the ZZ-cutinase-(WP)4 protein were also retained when added to the ATPS directly from an E. coli total cell disintegrate, emphasizing the applicability of this genetic engineering strategy for primary protein purification in ATPSs.

    Further on, a combinatorial library approach using phage display technology was investigated as a tool for identification of peptide tags capable of improving partitioning properties of ZZ-cutinase in an ATPS. Repeated ATPS-based partitioning-selection cycles of a large phagemid (pVIII) peptide library, resulted in isolation of phage particles preferentially decorated with peptides rich in tyrosine and proline residues. Both a peptide corresponding to a phage library derived peptide sequence as well as peptides designed based on information of amino acid appearance frequencies in later selection rounds, were shown to improve partitioning several-fold when genetically fused to the C-terminal end of ZZ-cutinase. From the two- to four–fold increased production yields observed for these fusion proteins compared to ZZ-cutinase-(WP)4, it was concluded that the selection system used allowed for selection of desired peptide properties related to both partitioning and E. coli protein production parameters.

    Bacterial protein production is affected by several different mRNA and protein sequence-related features. Attempts to address single parameters in this respect are difficult due to the inter-dependence of many features, for example between codon optimization and mRNA secondary structure effects. Two combinatorial expression vector libraries (ExLib1 and ExLib2) were constructed using a randomization strategy that potentially could lead to variations in many of these sequence-related features and which would allow a pragmatic search of vector variants showing positive net effects on the level of soluble protein production. ExLib1 was constructed to encode all possible synonymous codons of an eight amino acid N-terminal extension of protein Z, fused to the N-terminal of an enhanced green fluorescent reporter protein (EGFP). In ExLib2, the same eight positions were randomized using an (NNG/T) degeneracy code, which could lead to various effects on both the nucleotide and protein level, through the introduction of nucleotide sequences functional as e.g. alternative ribosome binding or translation initiation sites or as translated codons for an Nterminal extension of the target protein by a peptide sequence. Flow cytometric analyses and sorting of library cell cultures resulted in isolation of clones displaying several-fold increases in whole cell fluorescence compared to a reference clone. SDS-PAGE and western blot analyses verified that this was a result of increases (up to 24-fold) in soluble intracellular ZEGFP product protein content. Both position specific codon bias effects and the appearance of new ribosomal binding sites in the library sequences were concluded to have influenced the protein production.

    To explore the possibility of applying the same combinatorial library strategy for improving soluble intracellular production of heterologous proteins proven difficult to express in E. coli, three proteins with either bacterial (a transcriptional regulator (DntR)) or human (progesterone receptor ligand binding domain (PRLBD) and 11-β Hydroxysteroid dehydrogenase type I (11-β)) origin, were cloned into the ExLib2 library. Flow cytometric sorting of libraries resulted in isolation of DntR library clones showing increased soluble protein production levels and PR-LBD library clones with up to ten-fold increases in whole cell fluorescence, although the product under these conditions co-separated with the insoluble cell material.

  • 192.
    Bandmann, Nina
    et al.
    KTH, Tidigare Institutioner                               , Bioteknologi.
    Collet, Eric
    KTH, Tidigare Institutioner                               , Bioteknologi.
    Leijen, J
    Uhlén, M
    Veide, Andres
    KTH, Tidigare Institutioner                               , Bioteknologi.
    Nygren, Per-Åke
    KTH, Tidigare Institutioner                               , Bioteknologi.
    Genetic engineering of the Fusarium solani pisi lipase cutinase for enhanced partitioning in PEG-phosphate aqueous two-phase systems2000Ingår i: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 79, nr 2, s. 161-172Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Fusarium solani pisi lipase cutinase has been genetically engineered to investigate the influence of C-terminal peptide extensions on the partitioning of the enzyme in PEG-salt based aqueous two-phase bioseparation systems. Seven different cutinase lipase variants were constructed containing various C-terminal peptide extensions including tryptophan rich peptide tags ((WP)(2) and (WP)(4)), positively ((RP)(4)) and negatively ((DP)(4)) charged tags as well as combined tags with tryptophan together with either positively ((WPR)(4)) or negatively ((WPD)(4)) charged amino acids. The modified cutinase variants were stably produced in Escherichia coli as secreted to the periplasm from which they were efficiently purified by IgG-affinity chromatography employing an introduced N-terminal IgG-binding ZZ affinity fusion partner present in all variants. Partitioning experiments performed in a PEG 4000/sodium phosphate aqueous two-phase system showed that for variants containing either (WP)(2) or (WP)(4) peptide extensions, 10- to 70-fold increases in the partitioning to the PEG rich top-phase were obtained, when compared to the wild type enzyme. An increased partitioning was also seen for cutinase variants tagged with both tryptophans and charged amino acids, whereas the effect of solely charged peptide extensions was relatively small. In addition, when performing partitioning experiments from cell disintegrates, the (WP)(4)-tagged cutinase showed a similarly high PEG-phase partitioning, indicating that the effect from the peptide tag was unaffected by the background of the host proteins. Taken together, the results show that the partitioning of the recombinantly produced cutinase model enzyme could be significantly improved by relatively minor genetic engineering and that the effects observed for purified proteins are retained also in an authentic whole cell disintegrate system. The results presented should be of general interest also for the improvement of the partitioning properties of other industrially interesting proteins including bulk enzymes.

  • 193.
    Bandmann, Nina
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Löfdahl, Per-Åke
    KTH, Skolan för bioteknologi (BIO).
    Lönneborg, Rosa
    KTH, Skolan för bioteknologi (BIO).
    Älgenäs, Cajsa
    KTH, Skolan för bioteknologi (BIO).
    Nygren, Per-Åke
    KTH, Skolan för bioteknologi (BIO).
    Exploring the use of a combinatorial expression vector library for facilitated soluble recombinant protein productionManuskript (Övrigt vetenskapligt)
  • 194.
    Bandmann, Nina
    et al.
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Nygren, Per-Åke
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Combinatorial expression vector engineering for tuning of recombinant protein production in Escherichi coli2007Ingår i: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 35, nr 5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The complex and integrated nature of both genetic and protein level factors influencing recombinant protein production in Escherichia coli makes it difficult to predict the optimal expression strategy for a given protein. Here, two combinatorial library strategies were evaluated for their capability of tuning recombinant protein production in the cytoplasm of E. coli. Large expression vector libraries were constructed through either conservative (ExLib1) or free (ExLib2) randomization of a seven-amino-acid window strategically located between a degenerated start codon and a sequence encoding a fluorescently tagged target protein. Flow cytometric sorting and analyses of libraries, subpopulations or individual clones were followed by SDS-PAGE, western blotting, mass spectrometry and DNA sequencing analyses. For ExLib1, intracellular accumulation of soluble protein was shown to be affected by codon specific effects at some positions of the common N-terminal extension. Interestingly, for ExLib2 where the same sequence window was randomized via seven consecutive NN(G/T) tri-nucleotide repeats, high product levels (up to 24-fold higher than a reference clone) were associated with a preferential appearance of novel SID-like sequences. Possible mechanisms behind the observed effects are discussed.

  • 195.
    Bandmann, Nina
    et al.
    KTH, Tidigare Institutioner                               , Bioteknologi.
    van Alstine, James
    KTH, Tidigare Institutioner                               , Bioteknologi.
    Veide, Andres
    KTH, Tidigare Institutioner                               , Bioteknologi.
    Nygren, Per-Åke
    KTH, Tidigare Institutioner                               , Bioteknologi.
    Functional selection of phage displayed peptides for facilitated design of fusion tags improving aqueous two-phase partitioning of recombinant proteins2002Ingår i: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 93, nr 1, s. 1-14Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aqueous two-phase systems allow for the unequal distribution of proteins and other molecules in water-rich solutions containing phase separating polymers or surfactants. One approach to improve the partitioning properties of recombinant proteins is to produce the proteins as fused to certain peptide tags. However, the rational design of such tags has proven difficult since it involves a compromise between multivariate parameters such as partitioning properties, solvent accessibility and production/secretion efficiency. In this work, a novel approach for the identification of suitable peptide tag extensions has been investigated, Using the principles of selection, rather than design, peptide sequences contributing to an improved partitioning have been identified using phage display technology. A 40 million member phagemid library of random nona-peptides, displayed as fusion to the major coat protein pVIII of the filamentous phage M 13, was employed in the selection of top-phase partitioning phage particles in a PEG/sodium phosphate system. After multiple cycles of selection by partitioning, peptides with high frequencies of both tyrosine and proline residues were found to be over represented in selected clones. The identified peptide sequences, or derivatives thereof, were subsequently individually analyzed for their partitioning behavior as displayed on phage, as free synthetic peptides and as genetically fused to a recombinant model target protein. The results showed that novel peptide sequences capable of enhancing top-phase partitioning without interfering with protein production and secretion indeed could be identified for the aqueous two-phase system investigated.

  • 196.
    Banerjee, Indradumna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Nanobioteknologi.
    Russom, Aman
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Nanobioteknologi.
    Lab-on-DVD: Optical Disk Drive-Based Platforms for Point-of-Care Diagnostics2018Ingår i: Frugal Innovation in Bioengineering for the Detection of Infectious Diseases / [ed] AK Chavali, R Ramji, Switzerland: Springer, 2018, 2, s. 23-38Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    There is a growing demand for simple, affordable, reliable and quality-assured point-of-care (POC) diagnostics for use in resource-limited settings. Among the top ten leading causes of death worldwide, three are infectious diseases, namely, respiratory infections, HIV/AIDS and diarrheal diseases (World Health Organization 2012). Although high-quality diagnostic tests are available, these are often not available to patients in developing countries. While recent development in microfluidics and “lab-on-a-chip” devices has the potential to spur the development of protocols and affordable instruments for diagnosis of infectious disease at POC, integration of complex sample preparation and detection into automated molecular and cellular systems remain a bottleneck for implementation of these systems at resource-limited settings. Towards this, we describe here how low-cost optical drives can, with minor modifications, be turned into POC diagnostic platforms. A DVD drive is essentially a highly advanced and low-cost optical laser-scanning microscope, with the capability to deliver high-resolution images for biological applications. Furthermore, the inherent centrifugal force on rotational discs is elegantly used for sample preparation and integration. Hence, the merging of low-cost optical disc drives with centrifugal microfluidics is feasible concept for POC diagnostics, specifically designed to meet the needs at resource-limited settings.

  • 197.
    Bansal, Namita
    et al.
    DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing.
    Bhalla, Aditya
    DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing.
    Pattathil, Sivakumar
    University of Georgia, Complex Carbohydrate Research Center, University of Georgia, Athens, GA.
    Adelman, Sara L.
    DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing.
    Hahn, Michael G
    University of Georgia, Complex Carbohydrate Research Center, University of Georgia, Athens, GA.
    Hodge, David
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Hegg, Eric L.
    Michigan State University, DOE-Great Lakes Bioenergy Research Center, University of Wisconsin, Madison.
    Cell wall-associated transition metals improve alkaline-oxidative pretreatment in diverse hardwoods2016Ingår i: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 18, nr 5, s. 1405-1415Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The responses of four diverse hardwoods (hybrid poplar, silver birch, hybrid aspen, and sugar maple) to alkaline hydrogen peroxide (AHP) pretreated at ambient temperature and pressure were analyzed to gain a deeper understanding of the cell wall properties that contribute to differences in enzymatic hydrolysis efficacy following alkaline-oxidative pretreatment. The enzymatic hydrolysis yields of these diverse hardwoods increased significantly with increasing the cell wall-associated, redox-active transition metal content. These increases in hydrolysis yields were directly correlated with improved delignification. Furthermore, we demonstrated that these improvements in hydrolysis yields could be achieved either through elevated levels of naturally-occurring metals, namely Cu, Fe, and Mn, or by the addition of a homogeneous transition metal catalyst (e.g. Cu 2,2′-bipyridine complexes) capable of penetrating into the cell wall matrix. Removal of naturally-occurring cell wall-associated transition metals by chelation resulted in substantial decreases in the hydrolysis yields following AHP pretreatment, while re-addition of metals in the form of Cu 2,2′-bipyridine complexes and to a limited extent Fe 2,2′-bipyridine complexes prior to pretreatment restored the improved hydrolysis yields. Glycome profiles showed improved extractability of xylan, xyloglucan, and pectin epitopes with increasing hydrolysis yields for the diverse hardwoods subjected to the alkaline-oxidative pretreatment, demonstrating that the strength of association between cell wall matrix polymers decreased as a consequence of improved delignification

  • 198.
    Barbe, Laurent
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Lundberg, Emma
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Oksvold, Per
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Stenius, Anna
    KTH, Skolan för bioteknologi (BIO).
    Lewin, Erland
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Björling, Erik
    KTH, Skolan för bioteknologi (BIO).
    Asplund, Anna
    Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University.
    Pontén, Fredrik
    Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University.
    Brismar, Hjalmar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Uhlén, Mathias
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Andersson-Svahn, Helene
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Toward a confocal subcellular atlas of the human proteome2008Ingår i: Molecular and cellular proteomics, ISSN 1535-9476, Vol. 7, nr 3, s. 499-508Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Information on protein localization on the subcellular level is important to map and characterize the proteome and to better understand cellular functions of proteins. Here we report on a pilot study of 466 proteins in three human cell lines aimed to allow large scale confocal microscopy analysis using protein-specific antibodies. Approximately 3000 high resolution images were generated, and more than 80% of the analyzed proteins could be classified in one or multiple subcellular compartment(s). The localizations of the proteins showed, in many cases, good agreement with the Gene Ontology localization prediction model. This is the first large scale antibody-based study to localize proteins into subcellular compartments using antibodies and confocal microscopy. The results suggest that this approach might be a valuable tool in conjunction with predictive models for protein localization.

  • 199.
    Barghi, H.
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, M.J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthesis of an electroconductive membrane using poly(hydroxymethyl-3,4-ethylenedioxythiophene-co-tetramethylene-N-hydroxyethyl adipamide)2013Ingår i: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 1, nr 39, s. 6347-6354Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Synthesis of a novel electroconductive membrane (ECM) was studied with the aim of producing an electroconductive membrane (ECM) with low electrical resistance and appropriate mechanical properties. The method was based on copolymerization of a highly electroconductive monomer (hydroxymethyl-3,4-ethylenedioxythiophene) with highly mechanical resistant hydrophilized polyamide 46 (polytetramethylene-N-hydroxyethyl adipamide). Due to the lack of hydroxyl groups, polyamide 46 does not have the tendency to take part in any chemical reactions, therefore prior to copolymerization, PA 46 was hydrophilized with acetaldehyde to create reactive sites, which allowed copolymerization to occur. At the final stage, a very thin layer, 566 nm conductive poly(hydroxymethyl-3,4-ethylenedioxythiophene) homopolymer was localised using in situ plasma polymerization in order to improve the electrical conductivity of the obtained copolymer. The result was an adherent, highly conductive, semi-hydrophilic and flexible ECM. The presence of hydroxyl groups in the final product led to improved hydrophilicity of the conductive membrane with a surface tension of 41 mJ m−2. The electrical resistance of PA 46 was dramatically reduced after copolymerization, to 202 in dry and 54 kΩ cm−2 in wet conditions; furthermore, after plasma treatment, this reduction continued to 105 in dry and 2 kΩ cm−2 in wet conditions. Other parameters such as flux flow, roughness, pore size, pore distribution, contact angle, surface energy and thermal stability of the ECM were also investigated.

  • 200.
    Barghi, Hamidreza
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Catalytic Synthesis of Bulk Hydrophilic Acetaldehyde-Modified Polyamide 462014Ingår i: Current Organic Synthesis, ISSN 1570-1794, E-ISSN 1875-6271, Vol. 11, nr 6, s. 288-294Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydrophilization of Polyamide 46 (PA46) via modification with acetaldehyde in continuous phase was studied. The chemical modification of PA 46 with acetaldehyde resulted in a water-swollen polymer with hydrophilic property. The polyamide 46 undergoes a nucleophilic addition with acetaldehyde in the presence of aluminum chloride as a catalyst. The extent of bulk hydroxyethylation using AlCl3 resulted in 95.65% modification counted as total N-hydroxyethylated polyamide 46. The modification resulted in improved hydrophilic properties, and a maximum surface free energy of 44.6 mJ/m2 was achieved after 3 h reaction, whereas the unmodified PA46 had a surface free energy of 11.2 mJ/m2. In addition, thermal properties of the polymers were studied using differential scanning calorimetry and thermogravimetric analyses. The functionalization leads to decrease in the crystallization energy from 88 J/g to 51 J/g, while the melting energy is changed from 110 J/g to 53 J/g. Furthermore, the thermal stability of the PA46 to pyrolysis was diminished after hydroxylation.

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