Change search
Refine search result
12 51 - 57 of 57
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • 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.
  • 51. Spets, J. -P
    et al.
    Lampinen, M. J.
    Kiros, Yohannes
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Rantanen, J.
    Anttila, T.
    Effect of temperature on a direct glucose anion exchange membrane fuel cell in a near-neutral-state electrolyte2013In: International Journal of Electrochemical Science, ISSN 1452-3981, E-ISSN 1452-3981, Vol. 8, no 1, p. 1226-1236Article in journal (Refereed)
    Abstract [en]

    A direct glucose anion exchange membrane fuel cell (AEMFC) with a near-neutral-state electrolyte was studied at varying temperatures of 20, 30 and 37 ° C at two different concentrations of glucose of 0.1 and 0.3 M and with three concentrations of electrolyte of 0.1, 0.2 and 0.3 M [PO4]tot. The prime objective was to show how specific energy (W kg-1 glucose) of the direct glucose AEMFC is related to the operation temperature and concentrations of the species. Current and voltage values were measured together with the pHs and conductivities of the electrolytes. No component analysis of the final products after the fuel cell operation were done as the oxidation products of glucose is believed to be mainly gluconic acid and unreacted glucose as shown in the low Coulombic efficiency based on the exchange of 24 e-. Temperature, electrolyte and glucose concentrations have shown to have pronounced effect for the achievement of the highest energy capacity of 5.15 Wh kg-1 glucose.

  • 52. Spets, J-P
    et al.
    Kiros, Yohannes
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Kuosa, M. A.
    Rantanen, J.
    Lampinen, M. J.
    Saari, K.
    Bioorganic materials as a fuel source for low-temperature direct-mode fuel cells2010In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 55, no 26, p. 7706-7709Article in journal (Refereed)
    Abstract [en]

    In this study a direct-mode fuel cell in which the fuel and electrolyte are mixed with each other is tested. An alkaline electrolyte is used. The aim was to develop a fuel cell which operates directly by mixing the fuel with the electrolyte. The target is to create a fuel cell with a capacity of a few mW cm(-2) with starch as a fuel source. Starch, glucose, and sorbitol were tested as fuels for the fuel cell. With the selected fuel cell type and with glucose as the fuel, a maximum current density of 8 mA cm(-2) with a voltage of 0.5 V was obtained.

  • 53.
    Spets, J.-P
    et al.
    Helsinki University of Technology.
    Kiros, Yohannes
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Kuosa, M. A.
    Helsinki University of Technology.
    Rantanen, J.
    Helsinki University of Technology.
    Sallinen, J.
    Helsinki University of Technology.
    Lampinen, M. J.
    Helsinki University of Technology.
    Saari, K.
    Helsinki University of Technology.
    Starch and cellulose as fuel sources for low temperature direct mode fuel cells2008In: The Open Fuel Cells Journal, ISSN 1875-9327, Vol. 1, p. 1-3Article in journal (Refereed)
    Abstract [en]

    This paper is a study about a direct mode fuel cell with a near-neutral-state and alkaline electrolytes. The aim of study was to develop a fuel cell, which operates directly by mixing the fuel with the electrolyte. This arrangement helps to avoid inserting membranes and additional bacterial cultures in fuel cell. The target is also to create a fuel cell with a capacity of few mWcm-2 with the starch as a fuel. Also, glucose and sorbitol have been tested as fuel for the fuel cell.

  • 54.
    Spets, J.-P
    et al.
    Helsinki University of Technology.
    Kiros, Yohannes
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Noponen, T.
    Helsinki University of Technology.
    Kuosa, M. A.
    Helsinki University of Technology.
    Rantanen, J.
    Helsinki University of Technology.
    Lampinen, M. J.
    Helsinki University of Technology.
    Saari, K.
    Helsinki University of Technology.
    Direct-Mode Glucose Fuel Cells with Near-Neutral-State Electrolytes: Anode Electrode Studies with Different Catalysts and Electrolytes2009In: The Open Fuels & Energy Science Journal, ISSN 1876-973X, E-ISSN 1876-973X, Vol. 2, p. 82-86Article in journal (Refereed)
    Abstract [en]

    In the present study, a direct-mode glucose fuel cell with a neutral-state and near-neutral-state aqueous electrolytes is studied. The near-neutral state electrolytes are important for two reasons. Firstly, the pH of the electrolytes would be near the pH of liquid in living cells. Secondly, the neutral electrolyte would enable good corrosion resistance of catalyst materials. Three different catalyst materials, i.e. Pt-Pd, Raney-Ni and Ni-porphyrin complex, are tested in an anode half-cell configuration with one neutral-state (battery water) and with two near-neutral-state aqueous electrolytes, i.e. modified Krebs-Ringer (K-R) and phosphate, both buffered to a pH value of 7.4. Pt-Pd catalyst in the aqueous K-R electrolyte maintains the negative voltage of the anode half cell with higher current densities that the nickel catalysts do. To estimate the operation of the direct-mode glucose fuel cell, the K-R electrolyte from the anode half-cell tests is tested also in the cathode half-cell with combined catalyst of cobalt porphyrin complex and of spinel. The open circuit voltages and polarisation curves are measured. Also, preliminary results and oxidation degrees of glucose in the tests are shown. Based on our half cell measurements, there are high development demands for the electro-catalysts, which could work efficiently in the near-neutral-state electrolytes.

  • 55.
    Spets, J.-P
    et al.
    Helsinki University of Technology.
    Lampinen, M. J.
    Helsinki University of Technology.
    Kiros, Yohannes
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Anttila, T.
    Rantanen, J
    Helsinki University of Technology.
    Kuosa, M. A.
    Helsinki University of Technology.
    Saari, K.
    Helsinki University of Technology.
    The Progress in the Ongoing Development Work: Enhancement of GlucoseElectro-Oxidation in Direct-Mode Fuel Cells - An Update2009In: The Open Fuel Cells Journal, Vol. 2, p. 11-14Article in journal (Refereed)
    Abstract [en]

    This study deals with the R&D regarding the direct glucose fuel cell with a capacity of increasing the power density with glucose as a fuel. The direct-mode fuel cell in which the fuel and the alkaline electrolyte are mixed with each other is tested at room temperature. The direct-mode fuel cell is exposed to an externally generated electromagnetic field with 4 GHz sine signals between electrodes to cause both the splitting of the fuel molecule and the electrochemical oxidation. As a result from the use of the higher frequency signals, a maximum current density of 15 mAcm-2 has been achieved with the total voltage of 0.5 V.

  • 56.
    Tehrani, Nima Fotouhi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Aznar, Javier S.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Kiros, Yohannes
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Coffee extract residue for production of ethanol and activated carbons2015In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 91, p. 64-70Article in journal (Refereed)
    Abstract [en]

    Biomass as a waste product in the form coffee extract residue (CER) has been shown to have potential for the dual purpose of ethanol production and preparation of activated carbons. A straightforward method of direct hydrolysis and fermentation (DHF) is considered as the main option utilized in this study for the generation of fuel ethanol from the biomass waste. Factors such as loadings of saccharomyces cerevisiae, temperatures (21 and 30 degrees C) and substrate content were investigated to maximize the yield of ethanol. Ethanol production rates between 1.1 g and 0.70 g h(-1) kg(-1) without pretreatment and 2.7 and 23 g h(-1) kg(-1) dry substance with mild treatment were obtained, respectively. The CER was also used to prepare activated carbons using both chemical and physical activation methods. The effects of process parameters such as temperatures and concentrations of acid were varied and determined as to the yield, BET-surface areas and porosities of the final product. H3PO4 treatment at 600 degrees C and steam treatment at 700 degrees C show maximum surface area of >640 m(2) g(-1) with increased total pore and micropore volumes. (C) 2014 Elsevier Ltd. All rights reserved.

  • 57.
    Villa, M.
    et al.
    University of Bergamo.
    Nelli, P.
    University of Bergamo.
    Salvi, P.
    University of Bergamo.
    Kiros, Kiros
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Zangari, G.
    University of Virginia.
    The apparent capacitance of the electrode "charging" process2009In: Physical and Analytical Electrochemistry General Session - 215th ECS Meeting, San Francisco, CA, 2009, Vol. 19, no 32, p. 47-59Conference paper (Other academic)
    Abstract [en]

    We investigate simple models of the electrode charging (discharging) at constant current i, where the potential (E) is recorded as a function of time, or charge, q = i·t. Our goal is to assess the advantages of a representation in terms of capacitance, C = dq / dE ,vs. E. Such a plot is related with cyclic voltammetry (c.v.) plot (ic.v. vs E) at a constant rate (β = dE / dt) since, under appropriate circumstances, we should have C = ic.v. / β = dq / dE. We will discuss the following items: a) origins and suppression of the singularities in the capacitance pilots, b) effects of the finite charging currents, c) comparison between c.v. and electrode charging experiments.

12 51 - 57 of 57
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • 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