umu.sePublications
Change search
Refine search result
1 - 7 of 7
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. DeLuca, Thomas H
    et al.
    Zackrisson, Olle
    Gentili, Francesco
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Sellstedt, Anita
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Nilsson, Marie-Charlotte
    Ecosystem controls on nitrogen fixation in boreal feather moss communities.2007In: Oecologia, ISSN 0029-8549, Vol. 152, no 1, p. 121-30Article in journal (Refereed)
    Abstract [en]

    N fixation in feather moss carpets is maximized in late secondary successional boreal forests; however, there is limited understanding of the ecosystem factors that drive cyanobacterial N fixation in feather mosses with successional stage. We conducted a reciprocal transplant experiment to assess factors in both early and late succession that control N fixation in feather moss carpets dominated by Pleurozium schreberi. In 2003, intact microplots of moss carpets (30 cm × 30 cm × 10–20 cm deep) were excavated from three early secondary successional (41–101 years since last fire) forest sites and either replanted within the same stand or transplanted into one of three late successional (241–356 years since last fire) forest sites and the transverse was done for late successional layers of moss. Moss plots were monitored for changes in N-fixation rates by acetylene reduction (June 2003–September 2005) and changes in the presence of cyanobacteria on moss shoots by microscopy (2004). Forest nutrient status was measured using ionic resin capsules buried in the humus layer. Late successional forests exhibit high rates of N fixation and consistently high numbers of cyanobacteria on moss shoots, but low levels of available N. Conversely, early successional forests have higher N availability and have low rates of N fixation and limited presence of cyanobacteria on moss shoots. Transplantation of moss carpets resulted in a significant shift in presence and activity of cyanobacteria 1 year after initiation of the experiment responding to N fertility differences in early versus late successional forests.

  • 2.
    Gentili, Francesco
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Phosphorus, nitrogen and their interactions affect N-2 fixation, N isotope fractionation and N partitioning in Hippophae rhamnoides2006In: Symbiosis, ISSN 0334-5114, E-ISSN 1878-7665, Vol. 41, no 1, p. 39-45Article in journal (Refereed)
    Abstract [en]

    The interactive effects of varying phosphorus and nitrogen supplies on N-2 fixation, N isotope fractionation during N uptake, and N partitioning among plant parts were studied in the actinorhizal plant Hippophae rhamnoides L. (sea buckthorn). Plants were grown for six weeks after inoculation with the N-2-fixing actinomycete Frankia and differences in N accumulation were used to quantify N-2 fixation. N-15 natural abundance was analysed to study N isotope fractionation in specific plant parts in plants receiving different levels of N and P. Furthermore, the root system was split to study N isotope fractionation in roots supplied with different levels of N and P. Phosphorus stimulated N-2 fixation by direct effects on nodule dry matter and nodule function, rather than indirectly via plant growth. Phosphorus also stimulated N uptake from solution and influenced N isotope fractionation during N uptake. The inclusion of N-15 natural abundance analyses made it possible to detect P effects on N uptake, fractionation and N-2 fixation even though the plants used both N-2 fixation and combined N as N sources.

  • 3.
    Gentili, Francesco
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Nilsson, Marie-Charlotte
    Zackrisson, Olle
    DeLuca, Thomas H
    Sellstedt, Anita
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Physiological and molecular diversity of feather moss associative N2-fixing cyanobacteria.2005In: Journal of Experimental Botany, ISSN 0022-0957, Vol. 56, no 422, p. 3121-7Article in journal (Refereed)
    Abstract [en]

    Cyanobacteria colonizing the feather moss Pleurozium schreberi were isolated from moss samples collected in northern Sweden and subjected to physiological and molecular characterization. Morphological studies of isolated and moss-associated cyanobacteria were carried out by light microscopy. Molecular tools were used for cyanobacteria identification, and a reconstitution experiment of the association between non-associative mosses and cyanobacteria was conducted. The influence of temperature on N2 fixation in the different cyanobacterial isolates and the influence of light and temperature on N2-fixation rates in the moss were studied using the acetylene reduction assay. Two different cyanobacteria were effectively isolated from P. schreberi: Nostoc sp. and Calothrix sp. A third genus, Stigonema sp. was identified by microscopy, but could not be isolated. The Nostoc sp. was found to fix N2 at lower temperatures than Calothrix sp. Nostoc sp. and Stigonema sp. were the predominant cyanobacteria colonizing the moss. The attempt to reconstitute the association between the moss and cyanobacteria was successful. The two isolated genera of cyanobacteria in feather moss samples collected in northern Sweden differ in their temperature optima, which may have important ecological implications.

  • 4.
    Werner, Kajsa
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Piotrowska, Patrycja
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Gentili, Francesco
    Swedish University of Agricultural Sciences.
    Holmlund, Mattias
    Swedish University of Agricultural Sciences, SLU.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Characterization of Thermochemical Fuel Properties of Microalgae and Cyanobacteria2014In: Impacts of Fuel Quality on Power Production October 26 –31, 2014, Snowbird, Utah, USA, 2014Conference paper (Other academic)
  • 5.
    Zackrisson, O
    et al.
    Swedish University of Agricultural Sciences Department of Forest Ecology and Management, Umeå, Sweden.
    Deluca, T
    Swedish University of Agricultural Sciences Department of Forest Ecology and Management, Umeå, Sweden.
    Gentili, Francesco
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Sellstedt, Anita
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Jäderlund, A
    Swedish University of Agricultural Sciences Department of Forest Ecology and Management, Umeå, Sweden.
    Nitrogen fixation in mixed Hylocomium splendens moss communities2009In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 160, no 2, p. 309-319Article in journal (Refereed)
    Abstract [en]

    The pleurocarpus feather moss, Hylocomium splendens, is one of two co-dominant moss species in boreal forest ecosystems and one of the most common mosses on earth, yet little is known regarding its capacity to host cyanobacterial associates and thus contribute total ecosystem N. In these studies, we evaluated the N-fixation potential of the H. splendens-cyanobacteria association and contrasted the N-fixation activity with that of the putative N-fixing moss-cyanobacteria association of Pleurozium schreberi. Studies were conducted to: quantify N-fixation in H. splendens and P. schreberi in sites ranging from southern to northern Fennoscandia; assess N and P availability as drivers of N-fixation rates; contrast season-long N-fixation rates for both mosses; and characterize the cyanobacteria that colonize shoots of H. splendens. Nitrogen-fixation rates were generally low at southern latitudes and higher at northern latitudes (64-69 degrees N) potentially related to anthropogenic N deposition across this gradient. Nitrogen fixation in H. splendens appeared to be less sensitive to N deposition than P. schreberi. The season-long assessment of N-fixation rates at a mixed feather moss site in northern Sweden showed that H. splendens fixed a substantial quantity of N, but about 50% less total N compared to the contribution from P. schreberi. In total, both species provided 1.6 kg fixed N ha(-1) year(-1). Interestingly, H. splendens demonstrated somewhat higher N-fixation rates at high fertility sites compared to P. schreberi. Nostoc spp. and Stigonema spp. were the primary cyanobacteria found to colonize H. splendens and P. schreberi. These results suggest that H. splendens with associated Nostoc or Stigonema communities contributes a significant quantity of N to boreal forest ecosystems, but the contribution is subordinate to that of P. schreberi at northern latitudes. Epiphytic cyanobacteria are likely a key factor determining the co-dominant presence of these two feather mosses across the boreal biome.

  • 6. Zhu, Youjian
    et al.
    Piotrowska, Patrycja
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    van Eyk, Philip J.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kwong, Chi Wai
    Wang, Dingbiao
    Cole, Andrew J.
    de Nys, Rocky
    Gentili, Francesco G.
    Ashman, Peter J.
    Cogasification of Australian Brown Coal with Algae in a Fluidized Bed Reactor2015In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 29, no 3, p. 1686-1700Article in journal (Refereed)
    Abstract [en]

    Recently, the use of algae for CO2 abatement, wastewater treatment, and energy production has increasingly gained attention worldwide. In order to explore the potential of using algae as an alternative fuel as well as the possible challenges related to the algae gasification process, two species of macroalgae, Derbesia tenuissima and Oedogonium sp., and one type of microalgae, Scenedesmus sp. were studied in this research. In this work, Oedogonium sp. was cultivated with two protocols: producing biomass with both high and low levels of nitrogen content. Cogasification of 10 wt % algae with an Australian brown coal was performed in a fluidized bed reactor, and the effects of algae addition on syngas yield, ash composition, and bed agglomeration were investigated. It was found that CO and H-2 yield increased and CO2 yield decreased after adding three types of macroalgae in the coal, with a slight increase of carbon conversion rate, compared to the coal alone experiment. In the case of coal/Scenedesmus sp, the carbon conversion rate decreased with lower CO/CO2/H-2 yield as compared to coal alone. Samples of fly ash, bed ash, and bed material agglomerates were analyzed using scanning electron microscopy combined with an energy dispersive X-ray detector (SEM-EDX) and X-ray diffraction (XRD). It was observed that both the fly ash and bed ash samples from all coal/macroalgae tests contained more Na and K as compared to the coal test. High Ca and Fe contents were also found in the fly ash and bed ash from the coal/Scenedesmus sp. test. Significant differences in the characteristics and compositions of the ash layer on the bed particles were observed from the different tests. Agglomerates were found in the bed material samples after the cogasification tests of coal/Oedogonium N+ and coal/Oedogonium N. The formation of liquid alkalisilicates on the sand particles was considered to be the main reason for agglomeration for the coal/Oedogonium N+ and coal/Oedogonium N tests. Agglomerates of fused ash and tiny silica sand particles were also found in the coal/Scenedesmus sp. test. In this case, however, the formation of a Fe-Al silicate eutectic mixture was proposed to be the main reason for agglomeration. Debersia was suggested to be a potential alternative fuel, which can be cogasified with brown coal without any significant operating problems under the current experimental conditions. However, for the other algae types, appropriate countermeasures are needed to avoid agglomeration and defluidization in the cogasification process.

  • 7.
    Zhu, Youjian
    et al.
    School of Energy and Power Engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan 450002, People’s Republic of China.
    Piotrowska, Patrycja
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    van Eyk, Philip Joseph
    School of Chemical Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Wu, Xuehong
    School of Energy and Power Engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan 450002, People’s Republic of China.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Zhang, Jun
    School of Energy and Power Engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan 450002, People’s Republic of China.
    Kwong, Chi Wai
    School of Chemical Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia.
    Wang, Dingbiao
    School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, Henan 450001, People’s Republic of China.
    Cole, Andrew J
    MACRO, the Centre for Macroalgal Resources and Biotechnology, James Cook University, Townsville, Queensland 4811, Australia.
    de Nys, Rocky
    MACRO, the Centre for Macroalgal Resources and Biotechnology, James Cook University, Townsville, Queensland 4811, Australia.
    Gentili, Francesco G.
    Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences (SLU), 901 83 Umeå, Sweden.
    Ashman, Peter J.
    School of Chemical Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia.
    Fluidized bed co-gasification of algae and wood pellets: gas yields and bed agglomeration analysis2016In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, no 3, p. 1800-1809Article in journal (Refereed)
    Abstract [en]

    Algae utilization in energy production has gained increasing attention as a result of its characteristics, such as high productivity, rapid growth rate, and flexible cultivation environment. In this paper, three species of algae, including a fresh water macroalgae, Oedogonium sp., a saltwater macroalgae, Derbersia tenuissima, and a microalgae species, Scenedesmus sp., were studied to explore the potential of using smaller amounts of algae fuels in blends with traditional woody biomasses in the gasification processes. Co-gasification of 10 wt % algae and 90 wt % Swedish wood pellets was performed in a fluidized bed reactor. The effects of algae addition on the syngas yield and carbon conversion rate were investigated. The addition of 10 wt % algae in wood increased the CO, H2, and CH4 yields by 3–20, 6–31, and 9–20%, respectively. At the same time, it decreased the CO2 yield by 3–18%. The carbon conversion rates were slightly increased with the addition of 10 wt % macroalgae in wood, but the microalgae addition resulted in a decrease of the carbon conversion rate by 8%. Meanwhile, the collected fly ash and bed material samples were analyzed using scanning electron microscopy combined with an energy-dispersive X-ray detector (SEM–EDX) and X-ray diffraction (XRD) technique. The fly ashes of wood/marcoalgae tests showed a higher Na content with lower Si and Ca contents compared to the wood test. The gasification tests were scheduled to last 4 h; however, only wood and wood/Derbersia gasification experiments were carried out without significant operational problems. The gasification of 10 wt % Oedogonium N+ and Oedogonium N– led to defluidization of the bed in less than 1 h, and the wood/Scenedesmus (WD/SA) test was stopped after 1.8 h as a result of severe agglomeration. It was found that the algae addition had a remarkable influence on the characteristics and compositions of the coating layer. The coating layer formation and bed agglomeration mechanism of wood/macroalgae was initiated by the reaction of alkali compounds with the bed particles to form low-temperature melting silicates (inner layer). For the WD/SA test, the agglomeration was influenced by both the composition of the original algae fuel as well as the external mineral contaminations. In summary, the operational problems experienced during the co-gasification tests of different algae–wood mixtures were assigned to the specific ash compositions of the different fuel mixtures. This showed the need for countermeasures, specifically to balance the high alkali content, to reach stable operation in a fluidized bed gasifier.

1 - 7 of 7
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf