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  • 1. Garcia-Gasulla, Dario
    et al.
    Poch, Mane
    Nieves, Juan Carlos
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Cortes, Ulises
    Turon, Claudia
    A logic-based environmental decision support system for the management of horizontal subsurface constructed wetlands2012In: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 47, p. 44-55Article in journal (Refereed)
    Abstract [en]

    The use of Horizontal Subsurface Constructed Wetlands (HSCWs) for treating wastewaters in small communities has increased in the last years due to HSCW's ecological singularities. Unfortunately, the same singularities that differentiate HSCWs complicate any attempt to develop models and produce generic decision-support systems for them. Classical mathematical and statistical approaches used in other Wastewater Treatment Plants do not properly fit the particularities of HSCW and provide little insight in the domain of HSCW. We introduce a novel approach based on logic-based declarative specifications, i.e. non-monotonic causal logic, to capture explicit and implicit knowledge about HSCWs. By expressing all the relevant aspects of a HSCW in a declarative way, we produce a logic-based model which captures features that other approaches fail to formalize. At the end, we produce a complete decision-support system based on that model and test it against a set of realistic scenarios validated by experts. We discuss in which aspects this approach performs better than the most commonly proposed solutions in the bibliography and why it does so. (C) 2012 Elsevier B.V. All rights reserved.

  • 2.
    Ouyang, Wei
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. School of Environment, State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing, China.
    Zhao, Xuchen
    Umeå University, Faculty of Science and Technology, Department of Chemistry. School of Environment, State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing, China.
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Haoa, Fanghua
    Wang, Fangli
    Optimisation of corn straw biochar treatment with catalytic pyrolysisin intensive agricultural area2015In: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 84, p. 278-286Article in journal (Refereed)
    Abstract [en]

    The crop biomass treatment is the challenging issue in the intensive agricultural area and the catalyst has the potential to solve this problem. This preliminary study examined the response of the corn straw biochar treatment to the catalytic pyrolysis and applications of catalyst to the sustainable agricultural with cost savings. The surface morphology of corn straw after pyrolysis was compared with the electron microscope scanned images. The pyrolytic characteristics and kinetics of corn straw were studied using a thermogravimetric analyser from ambient temperature to 900 °C under a nitrogen atmosphere at heating rates of 10, 20, 30 and 40 °C min−1. The mass loss and the rate of mass loss curves derived from the pyrolysis of corn straw biochar and the biochar with the addition of 5% (wt.%) ammonium dihydrogen phosphate (ADP) catalyst. The pyrolysis process was consisted of three distinct stages, and impact of catalyst on the temperature distribution was distinguished. The catalytic pyrolysis process was mainly categorised by removal of water including free water and combined water, decomposition of hemicellulose, cellulose and lignin; and carbonisation. With the increase of pyrolysis rate, the maximum weight loss temperature shifted to lower temperatures. The kinetic process characteristics of corn straw biochar at three levels of ADP addition and four kinds of temperature were calculated. The activation energies and pre-exponential factors of the pyrolysis process were calculated by the Flynn–Wall–Ozawa method, modified Coats–Redfern model-free method and Kissinger method. The detailed information of kinetic parameters also helped to improve the biomass pyrolysis process. The analysis demonstrated that the ADP had a catalytic effect on the pyrolysis behaviour of biomass and was able to reduce the activation energy of biomass pyrolysis. Therefore, the catalyst can improve the pyrolysis process and have great potential to increase crop residue treatment efficiency, especially in the intensive agricultural area.

  • 3. Pu, Xiao
    et al.
    Cheng, Hongguang
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Xie, Jing
    Lu, Lu
    Yang, Shengtian
    Indications of soil properties on dissolved organic carbon variability following a successive land use conversion2018In: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 117, p. 115-119Article in journal (Refereed)
    Abstract [en]

    In seasonal freeze-thaw zones of NE China, the policy-oriented land management has caused successive land use conversions of native woodland, dry cropland and paddy field for food security. Controls of soil property factors on soil dissolved organic carbon (DOC) dynamics might vary with deforestation. This study aimed to test performance of soil properties interpreting DOC variability along soil profile following a vegetation succession of native forest, rainfed crops (maize-soybean rotations) and paddy rice in an observation area of the Sanjiang Plain. The linear mixed effects model evaluated relative importance of soil properties with comparisons of adjusting and not adjusting for random effects of land use and soil depth as subject variables. The modeling results revealed presence of consistent soil property factors indicating DOC dynamics before and after deforestation. When excluding interferences of land uses and soil layers, interpretations of soil properties were weakened. Soil moisture and bulk density predominantly accounted for DOC variability across land uses, presenting greater estimated effects (0.69 and -0.64, respectively) over those of total nitrogen, soil organic carbon and hydrolyzable nitrogen (0.49, 0.44 and 0.31, respectively). But no soil property factor indicated DOC variability with soil depth. Further research is needed to understand why indications of soil moisture and bulk density on DOC dynamics would differ between horizontal and vertical.

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