108 results on '"Kostas, S."'
Search Results
2. Multi-period mean-variance fuzzy portfolio optimization model with transaction costs.
- Author
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Konstantinos Liagkouras and Kostas S. Metaxiotis
- Published
- 2018
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3. A new efficiently encoded multiobjective algorithm for the solution of the cardinality constrained portfolio optimization problem.
- Author
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Konstantinos Liagkouras and Kostas S. Metaxiotis
- Published
- 2018
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4. Esterification of free fatty acids using acidic metal oxides and supported polyoxometalate (POM) catalysts
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Avramidou, Kalliopi V., Zaccheria, Federica, Karakoulia, Stamatia A., Triantafyllidis, Kostas S., and Ravasio, Nicoletta
- Published
- 2017
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5. The IASLC Lung Cancer Staging Project: External Validation of the Revision of the TNM Stage Groupings in the Eighth Edition of the TNM Classification of Lung Cancer
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Goldstraw, Peter, Rami-Porta, Ramón, Asamura, Hisao, Ball, David, Beer, David G., Beyruti, Ricardo, Bolejack, Vanessa, Chansky, Kari, Crowley, John, Detterbeck, Frank, Erich Eberhardt, Wilfried Ernst, Edwards, John, Galateau-Sallé, Françoise, Giroux, Dorothy, Gleeson, Fergus, Groome, Patti, Huang, James, Kennedy, Catherine, Kim, Jhingook, Kim, Young Tae, Kingsbury, Laura, Kondo, Haruhiko, Krasnik, Mark, Kubota, Kaoru, Lerut, Antoon, Lyons, Gustavo, Marino, Mirella, Marom, Edith M., van Meerbeeck, Jan, Mitchell, Alan, Nakano, Takashi, Nicholson, Andrew G., Nowak, Anna, Peake, Michael, Rice, Thomas, Rosenzweig, Kenneth, Ruffini, Enrico, Rusch, Valerie, Saijo, Nagahiro, Van Schil, Paul, Sculier, Jean-Paul, Shemanski, Lynn, Stratton, Kelly, Suzuki, Kenji, Tachimori, Yuji, Thomas, Charles F., Jr., Travis, William, Tsao, Ming S., Turrisi, Andrew, Vansteenkiste, Johan, Watanabe, Hirokazu, Wu, Yi-Long, Baas, Paul, Erasmus, Jeremy, Hasegawa, Seiki, Inai, Kouki, Kernstine, Kemp, Kindler, Hedy, Krug, Lee, Nackaerts, Kristiaan, Pass, Harvey, Rice, David, Falkson, Conrad, Filosso, Pier Luigi, Giaccone, Giuseppe, Kondo, Kazuya, Lucchi, Marco, Okumura, Meinoshin, Blackstone, Eugene, Cavaco, F. Abad, Barrera, E. Ansótegui, Arca, J. Abal, Lamelas, I. Parente, Obrer, A. Arnau, Jorge, R. Guijarro, Ball, D., Bascom, G.K., Orozco, A. I. Blanco, Castro, M. A. González, Blum, M.G., Chimondeguy, D., Cvijanovic, V., Defranchi, S., de Olaiz Navarro, B., Campuzano, I. Escobar, Vidueira, I. Macía, Araujo, E. Fernández, García, F. Andreo, Fong, K.M., Corral, G. Francisco, González, S. Cerezo, Gilart, J. Freixinet, Arangüena, L. García, Barajas, S. García, Girard, P., Goksel, T., Budiño, M. T. González, Casaurrán, G. González, Blanco, J. A. Gullón, Hernández, J. Hernández, Rodríguez, H. Hernández, Collantes, J. Herrero, Heras, M. Iglesias, Elena, J. M. Izquierdo, Jakobsen, E., Kostas, S., Atance, P. León, Ares, A. Núñez, Liao, M., Losanovscky, M., Lyons, G., Magaroles, R., De Esteban Júlvez, L., Gorospe, M. Mariñán, McCaughan, B., Kennedy, C., Íñiguez, R. Melchor, Sorribes, L. Miravet, Gozalo, S. Naranjo, Álvarez de Arriba, C., Delgado, M. Núñez, Alarcón, J. Padilla, Cuesta, J. C. Peñalver, Park, J.S., Pass, H., Fernández, M. J. Pavón, Rosenberg, M., Ruffini, E., Rusch, V., Sánchez de Cos Escuín, J., Vinuesa, A. Saura, Mitjans, M. Serra, Strand, T.E., Subotic, D., Swisher, S., Terra, R., Thomas, C., Tournoy, K., Van Schil, P., Velasquez, M., Wu, Y.L., Yokoi, K., Detterbeck, Frank C., Rusch, Valerie W., Vallières, Eric, and Crowley, John J.
- Published
- 2017
- Full Text
- View/download PDF
6. An experimental analysis of a new two-stage crossover operator for multiobjective optimization.
- Author
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Konstantinos Liagkouras and Kostas S. Metaxiotis
- Published
- 2017
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7. Enhancing the performance of MOEAs: an experimental presentation of a new fitness guided mutation operator.
- Author
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Konstantinos Liagkouras and Kostas S. Metaxiotis
- Published
- 2017
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8. Effect of high surface area mesoporous silica fillers (MCF and SBA-15) on solid state polymerization of PET
- Author
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Achilias, Dimitris S., Gerakis, Kostas, Giliopoulos, Dimitrios J., Triantafyllidis, Kostas S., and Bikiaris, Dimitrios N.
- Published
- 2016
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9. The IASLC Lung Cancer Staging Project: Proposals for Revision of the TNM Stage Groupings in the Forthcoming (Eighth) Edition of the TNM Classification for Lung Cancer
- Author
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Goldstraw, Peter, Rami-Porta, Ramón, Asamura, Hisao, Ball, David, Beer, David G., Beyruti, Ricardo, Bolejack, Vanessa, Chansky, Kari, Crowley, John, Detterbeck, Frank, Erich Eberhardt, Wilfried Ernst, Edwards, John, Galateau-Sallé, Françoise, Giroux, Dorothy, Gleeson, Fergus, Groome, Patti, Huang, James, Kennedy, Catherine, Kim, Jhingook, Kim, Young Tae, Kingsbury, Laura, Kondo, Haruhiko, Krasnik, Mark, Kubota, Kaoru, Lerut, Antoon, Lyons, Gustavo, Marino, Mirella, Marom, Edith M., van Meerbeeck, Jan, Mitchell, Alan, Nakano, Takashi, Nicholson, Andrew G., Nowak, Anna, Peake, Michael, Rice, Thomas, Rosenzweig, Kenneth, Ruffini, Enrico, Rusch, Valerie, Saijo, Nagahiro, Van Schil, Paul, Sculier, Jean-Paul, Shemanski, Lynn, Stratton, Kelly, Suzuki, Kenji, Tachimori, Yuji, Thomas, Charles F., Jr., Travis, William, Tsao, Ming S., Turrisi, Andrew, Vansteenkiste, Johan, Watanabe, Hirokazu, Wu, Yi-Long, Baas, Paul, Erasmus, Jeremy, Hasegawa, Seiki, Inai, Kouki, Kernstine, Kemp, Kindler, Hedy, Krug, Lee, Nackaerts, Kristiaan, Pass, Harvey, Rice, David, Falkson, Conrad, Filosso, Pier Luigi, Giaccone, Giuseppe, Kondo, Kazuya, Lucchi, Marco, Okumura, Meinoshin, Blackstone, Eugene, Abad Cavaco, F., Ansótegui Barrera, E., Abal Arca, J., Parente Lamelas, I., Arnau Obrer, A., Guijarro Jorge, R., Ball, D., Bascom, G.K., Blanco Orozco, A.I., González Castro, M.A., Blum, M.G., Chimondeguy, D., Cvijanovic, V., Defranchi, S., de Olaiz Navarro, B., Escobar Campuzano, I., Macía Vidueira, I., Fernández Araujo, E., Andreo García, F., Fong, K.M., Francisco Corral, G., Cerezo González, S., Freixinet Gilart, J., García Arangüena, L., García Barajas, S., Girard, P., Goksel, T., González Budiño, M.T., González Casaurrán, G., Gullón Blanco, J.A., Hernández Hernández, J., Hernández Rodríguez, H., Herrero Collantes, J., Iglesias Heras, M., Izquierdo Elena, J.M., Jakobsen, E., Kostas, S., León Atance, P., Núñez Ares, A., Liao, M., Losanovscky, M., Lyons, G., Magaroles, R., De Esteban Júlvez, L., Mariñán Gorospe, M., McCaughan, B., Kennedy, C., Melchor Íñiguez, R., Miravet Sorribes, L., Naranjo Gozalo, S., Álvarez de Arriba, C., Núñez Delgado, M., Padilla Alarcón, J., Peñalver Cuesta, J.C., Park, J.S., Pass, H., Pavón Fernández, M.J., Rosenberg, M., Ruffini, E., Rusch, V., Sánchez de Cos Escuín, J., Saura Vinuesa, A., Serra Mitjans, M., Strand, T.E., Subotic, D., Swisher, S., Terra, R., Thomas, C., Tournoy, K., Van Schil, P., Velasquez, M., Wu, Y.L., Yokoi, K., Rami-Porta, Ramon, and Eberhardt, Wilfried E.E.
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- 2016
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10. d-Glucose hydrogenation/hydrogenolysis reactions on noble metal (Ru, Pt)/activated carbon supported catalysts
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Lazaridis, Polykarpos A., Karakoulia, Stamatia, Delimitis, Andreas, Coman, Simona M., Parvulescu, Vasile I., and Triantafyllidis, Kostas S.
- Published
- 2015
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11. Effect of organoclays type on solid-state polymerization (SSP) of poly(ethylene terephthalate): Experimental and modeling
- Author
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Achilias, Dimitris S., Karandrea, Eva, Triantafyllidis, Kostas S., Ladavos, Athanasios, and Bikiaris, Dimitrios N.
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- 2015
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12. Nanocatalysis in the Fast Pyrolysis of Lignocellulosic Biomass
- Author
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Iliopoulou, Eleni F., primary, Lazaridis, Polykarpos A., additional, and Triantafyllidis, Kostas S., additional
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- 2017
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13. Catalytic Pyrolysis of Biomass for Transportation Fuels
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Lappas, Angelos A., primary, Kalogiannis, Kostas G., additional, Iliopoulou, Eleni F., additional, Triantafyllidis, Kostas S., additional, and Stefanidis, Stylianos D., additional
- Published
- 2015
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14. The IASLC Lung Cancer Staging Project: Background Data and Proposals for the Classification of Lung Cancer with Separate Tumor Nodules in the Forthcoming Eighth Edition of the TNM Classification for Lung Cancer
- Author
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Detterbeck, Frank C., Bolejack, Vanessa, Arenberg, Douglas A., Crowley, John, Donington, Jessica S., Franklin, Wilbur A., Girard, Nicolas, Marom, Edith M., Mazzone, Peter J., Nicholson, Andrew G., Rusch, Valerie W., Tanoue, Lynn T., Travis, William D., Asamura, Hisao, Rami-Porta, Ramón, Goldstraw, Peter, Rami-Porta, Ramón, Asamura, Hisao, Ball, David, Beer, David G., Beyruti, Ricardo, Bolejack, Vanessa, Chansky, Kari, Crowley, John, Detterbeck, Frank, Erich Eberhardt, Wilfried Ernst, Edwards, John, Galateau-Sallé, Françoise, Giroux, Dorothy, Gleeson, Fergus, Groome, Patti, Huang, James, Kennedy, Catherine, Kim, Jhingook, Kim, Young Tae, Kingsbury, Laura, Kondo, Haruhiko, Krasnik, Mark, Kubota, Kaoru, Lerut, Antoon, Lyons, Gustavo, Marino, Mirella, Marom, Edith M., van Meerbeeck, Jan, Mitchell, Alan, Nakano, Takashi, Nicholson, Andrew G., Nowak, Anna, Peake, Michael, Rice, Thomas, Rosenzweig, Kenneth, Ruffini, Enrico, Rusch, Valerie, Saijo, Nagahiro, Van Schil, Paul, Sculier, Jean-Paul, Shemanski, Lynn, Stratton, Kelly, Suzuki, Kenji, Tachimori, Yuji, Thomas, Charles F., Jr., Travis, William, Tsao, Ming S., Turrisi, Andrew, Vansteenkiste, Johan, Watanabe, Hirokazu, Wu, Yi-Long, Baas, Paul, Erasmus, Jeremy, Hasegawa, Seiki, Inai, Kouki, Kernstine, Kemp, Kindler, Hedy, Krug, Lee, Nackaerts, Kristiaan, Pass, Harvey, Rice, David, Falkson, Conrad, Filosso, Pier Luigi, Giaccone, Giuseppe, Kondo, Kazuya, Lucchi, Marco, Okumura, Meinoshin, Blackstone, Eugene, Flieder, Douglas, Godoy, Myrna, Goo, Jin Mo, Goodman, Lawrence R., Jett, Jim, de Leyn, Paul, Marchevsky, Alberto, MacMahon, Heber, Naidich, David, Okada, Morohito, Perlman, Marina, Powell, Charles, van Schil, Paul, Warth, Arne, Cavaco, Abad F., Barrera, Ansótegui E., Arca, Abal J., Lamelas, Parente I., Obrer, Arnau A., Jorge, Guijarro R., Ball, D., Bascom, G. K., Blanco Orozco, A. I., González Castro, M. A., Blum, M. G., Chimondeguy, D., Cvijanovic, V., Defranchi, S., de Olaiz Navarro, B., Campuzano, Escobar I., Vidueira, Macía I., Araujo, Fernández E., García, Andreo F., Fong, K. M., Corral, Francisco G., González, Cerezo S., Gilart, Freixinet J., Arangüena, García L., Barajas, García S., Girard, P., Goksel, T., González Budiño, M. T., Casaurrán, González G., Gullón Blanco, J. A., Hernández, Hernández J., Rodríguez, Hernández H., Collantes, Herrero J., Heras, Iglesias M., Izquierdo Elena, J. M., Jakobsen, E., Kostas, S., Atance, León P., Ares, Núñez A., Liao, M., Losanovscky, M., Lyons, G., Magaroles, R., De Esteban Júlvez, L., Gorospe, Mariñán M., McCaughan, B., Kennedy, C., Íñiguez, Melchor R., Sorribes, Miravet L., Gozalo, Naranjo S., de Arriba, Álvarez C., Delgado, Núñez M., Alarcón, Padilla J., Peñalver Cuesta, J. C., Park, J. S., Pass, H., Pavón Fernández, M. J., Rosenberg, M., Ruffini, E., Rusch, V., de Cos Escuín, Sánchez J., Vinuesa, Saura A., Mitjans, Serra M., Strand, T. E., Subotic, D., Swisher, S., Terra, R., Thomas, C., Tournoy, K., Van Schil, P., Velasquez, M., Wu, Y. L., and Yokoi, K.
- Published
- 2016
- Full Text
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15. The IASLC Lung Cancer Staging Project: Summary of Proposals for Revisions of the Classification of Lung Cancers with Multiple Pulmonary Sites of Involvement in the Forthcoming Eighth Edition of the TNM Classification
- Author
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Detterbeck, Frank C., Nicholson, Andrew G., Franklin, Wilbur A., Marom, Edith M., Travis, William D., Girard, Nicolas, Arenberg, Douglas A., Bolejack, Vanessa, Donington, Jessica S., Mazzone, Peter J., Tanoue, Lynn T., Rusch, Valerie W., Crowley, John, Asamura, Hisao, Rami-Porta, Ramón, Goldstraw, Peter, Rami-Porta, Ramón, Asamura, Hisao, Ball, David, Beer, David G., Beyruti, Ricardo, Bolejack, Vanessa, Chansky, Kari, Crowley, John, Detterbeck, Frank, Erich Eberhardt, Wilfried Ernst, Edwards, John, Galateau-Sallé, Françoise, Giroux, Dorothy, Gleeson, Fergus, Groome, Patti, Huang, James, Kennedy, Catherine, Kim, Jhingook, Kim, Young Tae, Kingsbury, Laura, Kondo, Haruhiko, Krasnik, Mark, Kubota, Kaoru, Lerut, Antoon, Lyons, Gustavo, Marino, Mirella, Marom, Edith M., van Meerbeeck, Jan, Mitchell, Alan, Nakano, Takashi, Nicholson, Andrew G., Nowak, Anna, Peake, Michael, Rice, Thomas, Rosenzweig, Kenneth, Ruffini, Enrico, Rusch, Valerie, Saijo, Nagahiro, Van Schil, Paul, Sculier, Jean-Paul, Shemanski, Lynn, Stratton, Kelly, Suzuki, Kenji, Tachimori, Yuji, Thomas, Charles F., Jr., Travis, William, Tsao, Ming S., Turrisi, Andrew, Vansteenkiste, Johan, Watanabe, Hirokazu, Wu, Yi-Long, Baas, Paul, Erasmus, Jeremy, Hasegawa, Seiki, Inai, Kouki, Kernstine, Kemp, Kindler, Hedy, Krug, Lee, Nackaerts, Kristiaan, Pass, Harvey, Rice, David, Falkson, Conrad, Filosso, Pier Luigi, Giaccone, Giuseppe, Kondo, Kazuya, Lucchi, Marco, Okumura, Meinoshin, Blackstone, Eugene, Flieder, Douglas, Godoy, Myrna, Goo, Jin Mo, Goodman, Lawrence R., Jett, Jim, de Leyn, Paul, Marchevsky, Alberto, MacMahon, Heber, Naidich, David, Okada, Morohito, Perlman, Marina, Powell, Charles, van Schil, Paul, Warth, Arne, Cavaco, Abad F., Barrera, Ansótegui E., Arca, Abal J., Lamelas, Parente I., Obrer, Arnau A., Jorge, Guijarro R., Ball, D., Bascom, G. K., Blanco Orozco, A. I., González Castro, M. A., Blum, M. G., Chimondeguy, D., Cvijanovic, V., Defranchi, S., de Olaiz Navarro, B., Campuzano, Escobar I., Vidueira, Macía I., Araujo, Fernández E., García, Andreo F., Fong, K. M., Corral, Francisco G., González, Cerezo S., Gilart, Freixinet J., Arangüena, García L., Barajas, García S., Girard, P., Goksel, T., González Budiño, M. T., Casaurrán, González G., Gullón Blanco, J. A., Hernández, J., Rodríguez, Hernández H., Collantes, Herrero J., Heras, Iglesias M., Izquierdo Elena, J. M., Jakobsen, E., Kostas, S., Atance, León P., Ares, Núñez A., Liao, M., Losanovscky, M., Lyons, G., Magaroles, R., De Esteban Júlvez, L., Gorospe, Mariñán M., McCaughan, B., Kennedy, C., Íñiguez, Melchor R., Sorribes, Miravet L., Gozalo, Naranjo S., de Arriba, Álvarez C., Delgado, Núñez M., Alarcón, Padilla J., Peñalver Cuesta, J. C., Park, J. S., Pass, H., Pavón Fernández, M. J., Rosenberg, M., Ruffini, E., Rusch, V., de Cos Escuín, Sánchez J., Vinuesa, Saura A., Mitjans, Serra M., Strand, T. E., Subotic, D., Swisher, S., Terra, R., Thomas, C., Tournoy, K., Van Schil, P., Velasquez, M., Wu, Y. L., and Yokoi, K.
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- 2016
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16. Activated carbons for the removal of heavy metal ions: A systematic review of recent literature focused on lead and arsenic ions
- Author
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Deliyanni Eleni A., Kyzas George Z., Triantafyllidis Kostas S., and Matis Kostas A.
- Subjects
adsorption ,lead ,arsenic ,wastewaters ,Chemistry ,QD1-999 - Published
- 2015
- Full Text
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17. Mesoporous Zeolite Catalysts for Biomass Conversion to Fuels and Chemicals
- Author
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Triantafyllidis, Kostas S., primary, Iliopoulou, Eleni F., additional, Karakoulia, Stamatia A., additional, Nitsos, Christos K., additional, and Lappas, Angelos A., additional
- Published
- 2015
- Full Text
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18. First pilot scale study of basic vs acidic catalysts in biomass pyrolysis: Deoxygenation mechanisms and catalyst deactivation
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H. Yiannoulakis, Angelos A. Lappas, Konstantinos G. Kalogiannis, Stamatia A. Karakoulia, Chrysoula M. Michailof, Kostas S. Triantafyllidis, and Stylianos D. Stefanidis
- Subjects
Hydrogen ,010405 organic chemistry ,020209 energy ,Process Chemistry and Technology ,chemistry.chemical_element ,Biomass ,02 engineering and technology ,Coke ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,Aldol condensation ,Deoxygenation ,Pyrolysis ,General Environmental Science ,Magnesite - Abstract
In order for catalytic biomass pyrolysis to be economically sustainable, low cost and highly efficient catalysts are needed. In a previous work, Magnesium oxide (MgO) basic catalysts produced from natural magnesite (MgCO3) were found to be highly efficient alternatives to zeolitic catalysts which apart from their relatively high cost, they are easily deactivated due to biomass alkali deposition. In order to validate these findings in pilot scale, these natural MgO catalysts were investigated in a circulating fluidized bed pilot scale unit and were compared to a commercially available ZSM-5 catalyst. This is to the best of our knowledge the first attempt to evaluate a basic catalyst in biomass fast pyrolysis in a pilot unit employing commercially relevant process technology. The basic sites of the MgO catalysts enhanced ketonization and aldol condensation reactions, as it was verified by 2DGC-TOFMS analyses of the produced bio-oils. Deoxygenation was achieved mainly via formation of CO2, while H2O yield was substantially reduced in comparison to the ZSM-5 catalyst. As a result, bio-oils richer in hydrogen were obtained by the use of MgOs. However, the MgO catalysts led to a significant increase of the catalytically produced coke compared to ZSM-5. The effect of MgO properties, such as surface area and basicity on product yields and bio-oil composition was elaborated. In contrast to the acidic ZSM-5, no alkali metals were found to deposit on MgO, indicating different deactivation mechanisms between acidic and basic catalysts in biomass fast pyrolysis.
- Published
- 2018
19. Diplomacy, hybrid leadership, and EU actorness: assessing the role of EU High Representative Catherine Ashton in the 2013 Kosovo-Serbia agreement
- Author
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Ribeiro, I. M. and Kostas, S.
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History ,Ciências Sociais::Sociologia [Domínio/Área Científica] ,Sociology and Political Science ,Kosovo ,Ciências Sociais::Economia e Gestão [Domínio/Área Científica] ,Western Balkans ,Leadership ,Ciências Sociais::Ciências Políticas [Domínio/Área Científica] ,Political Science and International Relations ,European Union ,High representative ,General Economics, Econometrics and Finance ,Actorness ,Serbia ,Humanidades::História e Arqueologia [Domínio/Área Científica] - Abstract
Over the last decade, the role of the European Union (EU) High Representative (HR/VP) became increasingly salient. However, a systematic understanding of how this figure’s leadership shaped the character of EU diplomacy and actorness in peacekeeping is lacking. To address this issue, we analyse Catherine Ashton’s leadership (as the first HR/VP post Lisbon Treaty) in the 2013 Kosovo-Serbia agreement, a high point of her tenure. We argue that Ashton’s success is largely due to her hybrid leadership, alternating between transactional and transformational and capitalising on the EU’s presence and opportunities as an international actor. We propose the concept of hybrid leadership as an analytical tool and illustrate its relevance in an empirical case study. Our examination of Ashton’s hybrid leadership contributes to shedding light on the potential role of the future HR/VPs and on how these can reinforce EU leadership, diplomacy, and actorness, contributing to reinforcing the corresponding academic debates. info:eu-repo/semantics/publishedVersion
- Published
- 2021
20. Effect of Lewis and Brønsted acidity on glucose conversion to 5-HMF and lactic acid in aqueous and organic media
- Author
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Antonio Pineda, Asimina A. Marianou, Kostas S. Triantafyllidis, Eleni F. Iliopoulou, Chrysoula M. Michailof, and Angelos A. Lappas
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Aqueous solution ,010405 organic chemistry ,Process Chemistry and Technology ,010402 general chemistry ,01 natural sciences ,Catalysis ,Product distribution ,0104 chemical sciences ,Lactic acid ,Solvent ,chemistry.chemical_compound ,chemistry ,Pyridine ,Selectivity ,Isomerization ,Nuclear chemistry - Abstract
Among the different metal-promoted catalysts for the conversion of C6 sugars to platform chemicals, Sn-based catalysts have demonstrated high activity for different types of reactions, such as isomerization, retro-aldol conversion and dehydration of glucose or its isomers. The form of Sn species, as oxides or ions, along with the properties of the support are important factors determining the prevalent reaction pathway and product distribution. In this framework, we have studied the conversion of glucose mainly in biphasic (H2O/DMSO) media, using four types of Sn-based catalysts, i.e. Sn(II) and Sn(IV) as homogeneous catalysts (Cl- salts) or as the respective oxides in heterogeneous systems, Sn(IV) as SnO2 supported on γ-Al2O3, zeolites (ZSM-5 and Beta) or mesoporous aluminosilicates (Al-MCM-41), and Snδ+ as ion-exchange cations on the above zeolites. The solid catalysts were characterized by XRD, FT-IR/pyridine, ICP-OES, XRF and N2 porosimetry. Under the studied conditions, the main products obtained were 5-HMF and lactic acid in both the homogeneous and heterogeneous systems. Based on the results obtained, it was concluded that the Lewis acidity offered by Sn oxides promotes the retro-aldol reaction pathway towards lactic acid, while the Lewis acidity offered by γ-Al2O3 enhances the synthesis of both 5-HMF and lactic acid. By combining these two functions, the Sn impregnated γ-Al2O3 catalysts induce further increase of both 5-HMF and lactic acid yields. In case of catalysts that possess Bronsted acidity as well (i.e. Sn ion-exchanged or impregnated zeolites and Al-MCM-41), dehydration reactions are promoted and the product selectivity is shifted towards 5-HMF synthesis. The highest 5-HMF molar yield of 27.5% (at complete glucose conversion) was achieved by Sn20/γ-Al2O3 accompanied by lactic acid at 16.5% molar yield. For this catalyst the effect of the solvent, catalyst concentration and reaction temperature and time, were further evaluated.
- Published
- 2018
21. Production of 5-HMF from Cellulosic Biomass: Experimental Results and Integrated Process Simulation
- Author
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N. Koukouzas, Angelos A. Lappas, Konstantinos Atsonios, Nikos Nikolopoulos, Chrysoula M. Michailof, Asimina A. Marianou, Kostas S. Triantafyllidis, Michael Alexandros Kougioumtzis, and Emmanuel Kakaras
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Environmental Engineering ,010405 organic chemistry ,Renewable Energy, Sustainability and the Environment ,Biomass ,010402 general chemistry ,medicine.disease ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Hydrolysis ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Cellulosic ethanol ,Ionic liquid ,medicine ,Process optimization ,Dehydration ,Cellulose ,Waste Management and Disposal - Abstract
5-Hydroxymethylfurfural (5-HMF) is one of the most promising biomass derived platform chemicals. It can be synthesized from biomass carbohydrates, mainly glucose and fructose, via dehydration under acidic conditions. The reaction may be performed either in water, ionic liquids or organic solvents, in particular polar aprotic solvents. In this work, the process modelling of a two-step synthesis of 5-HMF from biomass is presented. Starting from hemicellulose-free biomass, the first step includes the hydrolysis of cellulose towards glucose in the presence of H2SO4 as catalyst, while in a second step glucose is dehydrated to 5-HMF with the aid of Sn20/γ-Αl2O3 catalyst. Hydrolysis is performed in aqueous medium, while dehydration of glucose is taking place in a DMSO/H2O mixture. The overall production of 5-HMF is modelled via the chemical process optimization software ASPEN PLUS™. The optimized process is scaled up at an industrial scale where the heat integration, mass and energy balance calculations are performed.
- Published
- 2018
22. A new device for measuring the thermal conductivity of heterogeneous multicomponent thin samples: Development and application to polymer composites
- Author
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Thodoris D. Karapantsios, Margaritis Kostoglou, Kostas S. Triantafyllidis, M. Gannoum, and P. Xydas
- Subjects
Fluid Flow and Transfer Processes ,chemistry.chemical_classification ,Nanocomposite ,Materials science ,Polymer nanocomposite ,Mechanical Engineering ,010401 analytical chemistry ,02 engineering and technology ,Epoxy ,Polymer ,Conductivity ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Silicone rubber ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Thermal conductivity measurement ,Thermal conductivity ,chemistry ,visual_art ,visual_art.visual_art_medium ,Composite material ,0210 nano-technology - Abstract
A novel device for measuring the thermal conductivity of polymeric materials (pure polymers or nanocomposites) is presented here. Its design is based on two cylindrical tanks containing cold and hot water. Each tank wets one side of a disc-shaped polymeric sample. The proper selection of construction materials (aluminum body, Teflon fittings, etc.) and geometry (shape, size, etc.) of the two tanks and of the sample (diameter, thickness) renders the accurate measurement of the low thermal conductivity of several polymeric materials possible. The disc-shaped sample is placed in-between the two cylindrical tanks of the device, filled with cold and hot water. The water temperature in the two tanks is an adjustable operational parameter of the device. Both tank temperatures are recorded and fitted by a proper mathematical model in order to estimate the thermal conductivity of the sample. Extensive experimentation shows a very small scatter of the estimated conductivity values. The device was used to measure thermal conductivity of several polymers such as silicone rubber and epoxy resin prepared with a variety of cross-linkers and cross-linker blends. Moreover, the above polymers are used as matrices for the incorporation of various (nano)additives, like mesoporous silica foams (MCF) and organoclays (I.30E), for the preparation of the relative polymer nanocomposites whose thermal conductivity is measured.
- Published
- 2018
23. High hexitols selectivity in cellulose hydrolytic hydrogenation over platinum (Pt) vs. ruthenium (Ru) catalysts supported on micro/mesoporous carbon
- Author
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A. Panteli, Simona M. Coman, Stamatia A. Karakoulia, Kostas S. Triantafyllidis, Nicoleta G. Apostol, Andreas Delimitis, Vasile I. Parvulescu, D. Macovei, C. M. Teodorescu, and Polykarpos A. Lazaridis
- Subjects
010405 organic chemistry ,Process Chemistry and Technology ,Inorganic chemistry ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Ruthenium ,chemistry.chemical_compound ,chemistry ,Hydrogenolysis ,Reactivity (chemistry) ,Cellulose ,Platinum ,Mesoporous material ,Selectivity ,General Environmental Science - Abstract
The “ one-pot ” hydrolyltic hydrogenation of cellulose towards C2-C6 sugar alcohols has been recognized as one of the most promising biomass valorization routes for the production of high added-value chemicals. In this work, we studied the performance of Ru and Pt catalysts supported on micro/mesoporous activated carbon, in the hydrolytic hydrogenation of microcrystalline and ball-milled cellulose, in neat water, at 180 °C and at relatively low hydrogen pressure of 2 MPa. The impact of metal loading (1–5 wt.%), metal reduction method (H 2 at 350 °C or NaBH 4 ) and acidification (sulfonation) of the AC support on cellulose conversion and selectivity to the various products were systematically addressed. It was shown that Pt is significantly more selective towards hexitols (sorbitol and mannitol) compared to Ru, in glucose-rich reaction media, such as those offered by the easily hydrolyzed ball-milled cellulose. For example, the 5wt%Pt/AC-SO 3 H catalyst afforded hexitols yield of 69.5 wt.% (at 96.1% conversion) compared to 10.9 wt.% (at 95.2% wt.% conversion) obtained by the corresponding Ru catalyst, the latter being also selective towards glycerol and propane-1,2-diol (propylene glycol). A relatively moderate metal loading, such as in 3 wt.%Ru/AC-SO 3 H, was more favorable for hexitols production (44.5 wt.% yield, at 94.8 wt.% conversion) with Ru catalysts. These results were also verified by glucose hydrogenation experiments that were conducted at the same experimental conditions. Both Pt and Ru exhibited relatively high glucose hydrogenation activity towards hexitols, versus retro-aldol reactions that lead directly to smaller C2–C4 compounds, while the difference in the final product yields between the two metals was attributed to the higher hexitols hydrogenolysis (C C cleavage) reactivity of Ru. HRTEM data showed the formation of metallic crystalline Pt and Ru nanoparticles (≤4 nm, depending on loading) as well as of amorphous oxygen-rich M(O) x δ+ phases, which were also confirmed by the XPS data. The presence of these phases which may be a source of acidity, as well as the bacisity of the parent AC used in this study, were mainly responsible for inducing isomerization, retro-aldol and dehydration reactions leading eventually to increased glycerol and propylene glycol selectivity, as was observed for both low-metal catalysts, i.e. 1 wt.% Pt or Ru/AC.
- Published
- 2017
24. Imbalanced Ca/Mg and Ni excess effects on the growth, nutrient uptake, photosynthesis and antioxidant response of Punica granatum (cv. Granada) plants
- Author
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Chatzistathis, T., primary, Papaioannou, A., additional, Dichala, O., additional, Giannakoula, A., additional, Papaioannou, E., additional, and Kostas, S., additional
- Published
- 2019
- Full Text
- View/download PDF
25. Selective Reduction of Azines to Benzyl Hydrazones with Sodium Borohydride Catalyzed by Mesoporous Silica-Supported Silver Nanoparticles: A Catalytic Route towards Pyrazole Synthesis
- Author
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Michael G. Kallitsakis, Ioannis Charisteidis, Ioannis N. Lykakis, Evangelia Charistoudi, and Kostas S. Triantafyllidis
- Subjects
010405 organic chemistry ,Ethylenediamine ,General Chemistry ,Pyrazole ,Mesoporous silica ,010402 general chemistry ,Heterogeneous catalysis ,01 natural sciences ,Combinatorial chemistry ,Silver nanoparticle ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Sodium borohydride ,chemistry ,Organic chemistry ,Selective reduction - Abstract
The catalytic activity of supported silver nanoparticles on mesoporous silica was studied, for the selective reduction of azines into benzyl hydrazones using sodium borohydride as mild reducing agent. Different sizes of silver nanoparticles supported on mesoporous silica (Ag/HMS) were successfully prepared by two methods, i.e. wet impregnation followed by reduction with hydrogen at 350oC and in situ deposition/reduction with a mixture of amines (ethanolamine and ethylenediamine). The Ag/HMS (amines) catalyst was found to promote the selective 1,2-reduction of aryl-substituted azines, compared to the corresponding 1,4-reduction that occurs in general reduction processes. This catalytic transfer hydrogenation process found to be clear, fast and quantitative (>99% yields and selectivity) towards benzyl hydrazones synthesis under mild conditions. Of great importance is that under the present catalytic conditions reducible functional groups remain intact. Formal kinetics, support the in situ formation of silver-hydride species being responsible for the reduction process. The presence of protic polar methanol enhanced the catalytic activity of Ag/HMS. Based on the recycling studies the catalytic system Ag/HMS-NaBH4 was found to catalyze the selective reduction of azines nine times without significant loss of its activity. Finally, one-pot reaction between the in situ produced benzyl hydrazones and a series of nitrostyrenes readily provided the regioselective synthesis of 1,3,5,-subtituted pyrazoles, highlighting a useful synthetic application of the catalytic protocol.
- Published
- 2017
26. Natural magnesium oxide (MgO) catalysts: A cost-effective sustainable alternative to acid zeolites for the in situ upgrading of biomass fast pyrolysis oil
- Author
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E.F. Iliopoulou, Konstantinos G. Kalogiannis, Angelos A. Lappas, H. Yiannoulakis, Andreas Delimitis, Stamatia A. Karakoulia, Stylianos D. Stefanidis, Kostas S. Triantafyllidis, and T. Zampetakis
- Subjects
chemistry.chemical_classification ,020209 energy ,Process Chemistry and Technology ,Inorganic chemistry ,Lignocellulosic biomass ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Catalysis ,law.invention ,chemistry.chemical_compound ,Hydrocarbon ,chemistry ,law ,Pyrolysis oil ,0202 electrical engineering, electronic engineering, information engineering ,Calcination ,0210 nano-technology ,Zeolite ,Pyrolysis ,Deoxygenation ,General Environmental Science - Abstract
The thermal and catalytic fast pyrolysis of biomass aims at the production of pyrolysis oil (bio-oil), which can be utilized as a source of chemicals or as a bio-crude for the production of hydrocarbon fuels. We investigated low-cost, naturally derived basic MgO materials as catalysts for the catalytic fast pyrolysis of lignocellulosic biomass as alternatives to classical acidic zeolite catalysts. The MgO catalysts were produced from natural magnesite mineral without any significant treatment besides calcination, crushing and sieving. Their structure, composition, porosity, morphology and surface properties were thoroughly examined by XRD, XRF, N 2 porosimetry, SEM, TEM, TPD-CO 2 and TPD-NH 3 . The physicochemical characteristics of the MgO catalysts depended mainly on the different production conditions (duration and temperature of calcination). Despite their negligible acidity, the MgO catalysts effectively reduced the oxygen content of the produced bio-oil and exhibited similar or even better performance compared to that of an industrial ZSM-5 catalyst formulation ( i.e. non-catalytic pyrolysis: 38.9 wt.% organic bio-oil with 38.7 wt.% O 2 ; ZSM-5 based catalyst: 20.7 wt.% organic bio-oil with 30.9 wt.% O 2 ; selected natural MgO catalysts: 25.7 wt.% organic bio-oil with 31.0 wt.% O 2 or 21.1 wt.% organic bio-oil with 28.4 wt.% O 2 ). The basic sites of the MgO catalysts favored reduction of acids and deoxygenation via ketonization and aldol condensation reactions, as indicated by the product distribution and the composition of the bio-oil. Oxygen was removed mainly via the preferred pathway of CO 2 formation, compared to CO and water as in the case of ZSM-5 zeolite. On the other hand, reaction coke slightly increased over the MgO catalysts as compared to ZSM-5; however, the MgO formed coke was oxidized/burnt at significantly lower temperatures compared to that of ZSM-5, thus enabling MgO regeneration by relatively mild calcination in air. A systematic correlation of product yields and oxygen content of bio-oil with the physicochemical properties of the MgO catalysts has been established.
- Published
- 2016
27. Optimization of Hydrothermal Pretreatment of Hardwood and Softwood Lignocellulosic Residues for Selective Hemicellulose Recovery and Improved Cellulose Enzymatic Hydrolysis
- Author
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Konstantinos Matis, Christos Nitsos, Theodora Choli-Papadopoulou, and Kostas S. Triantafyllidis
- Subjects
0106 biological sciences ,Softwood ,Renewable Energy, Sustainability and the Environment ,020209 energy ,General Chemical Engineering ,Lignocellulosic biomass ,Biomass ,02 engineering and technology ,General Chemistry ,Pulp and paper industry ,01 natural sciences ,chemistry.chemical_compound ,Biobased economy ,chemistry ,010608 biotechnology ,Enzymatic hydrolysis ,Botany ,0202 electrical engineering, electronic engineering, information engineering ,Environmental Chemistry ,Lignin ,Hemicellulose ,Cellulose - Abstract
The sustainable utilization of lignocellulosic biomass as a renewable and abundant source lies at the core of the emerging biobased economy for the production of fuels, materials, and platform chemicals. The first step in the implementation of many biomass valorization technologies is the “pretreatment” that aims at biomass fractionation and recovery of its main structural components, i.e., cellulose, hemicellulose, and lignin, which can be then converted by downstream (bio)catalytic processes to targeted high added value intermediate chemicals or final products. In this respect, hydrothermal pretreatment in pure water (also called liquid hot water or autohydrolysis) offers a method with low operational costs, free of organic solvents and corrosive acids or bases, and with no use of “external” liquid or solid catalysts. In the present work, the hydrothermal pretreatment of three types of lignocellulosic forestry and agricultural residues/byproducts was studied. They are representative of hardwood (residua...
- Published
- 2016
28. Effect of high surface area mesoporous silica fillers (MCF and SBA-15) on solid state polymerization of PET
- Author
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Dimitrios N. Bikiaris, Kostas S. Triantafyllidis, Dimitris S. Achilias, Kostas Gerakis, and Dimitrios Giliopoulos
- Subjects
Thermogravimetric analysis ,Nanocomposite ,Ethylene ,Materials science ,Polymers and Plastics ,Scanning electron microscope ,Intrinsic viscosity ,Organic Chemistry ,General Physics and Astronomy ,02 engineering and technology ,Mesoporous silica ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Polymerization ,Polymer chemistry ,Materials Chemistry ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Nuclear chemistry - Abstract
In the current study the effect of different mesoporous silica particles like MCF and SBA-15 on the solid state polymerization (SSP) of poly(ethylene terephthalate) (PET) was investigated. PET nanocomposites containing 1 and 2.5 wt% SBA-15 silica (average pore diameter 4.7 nm) and MCF silica (average pore diameter 14.2 nm) have been prepared by in-situ polymerization. All nanocomposites have been characterized using FTIR spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). SSP was conducted at 220, 230 and 240 °C for 1, 2, 3 and 4 h under vacuum. Intrinsic viscosity (IV) measurements after solid-state polymerization of nanocomposites revealed that PET/SBA-15 nanocomposites exhibited lower IV increase compared to neat PET, while the opposite was observed for PET/MCF nanocomposites, especially for 1 wt% MCF content. A simple kinetic model was employed to predict the time evolution of IV, as well as the carboxyl and hydroxyl content during SSP at different temperatures and reaction times.
- Published
- 2016
29. Minimally invasive harvesting of bone patella tendon bone autografts in anterior cruciate ligament reconstruction: Surgical technique
- Author
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Romain Seil, Alexander Hoffmann, and Kostas S. Intzoglou
- Subjects
musculoskeletal diseases ,030222 orthopedics ,medicine.medical_specialty ,Anterior cruciate ligament reconstruction ,business.industry ,medicine.medical_treatment ,Physical Therapy, Sports Therapy and Rehabilitation ,030229 sport sciences ,musculoskeletal system ,Surgery ,03 medical and health sciences ,Bone patellar tendon bone ,0302 clinical medicine ,medicine.anatomical_structure ,Ligament ,medicine ,Orthopedics and Sports Medicine ,business - Abstract
Summary We present the technique of minimally invasive harvesting of bone patella tendon bone autografts for ligament reconstructions with 2 horizontal incisions. Technical guidelines as well as hints are described. The advantages and disadvantages of the technique are discussed with respect to current literature findings and the authors' experience with several hundreds of those interventions is reflected.
- Published
- 2016
30. Catalytic Fast Pyrolysis of Lignin over High-Surface-Area Mesoporous Aluminosilicates: Effect of Porosity and Acidity
- Author
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Victoria B. F. Custodis, Stamatia A. Karakoulia, Jeroen A. van Bokhoven, and Kostas S. Triantafyllidis
- Subjects
General Chemical Engineering ,010402 general chemistry ,Lignin ,complex mixtures ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,Environmental Chemistry ,Organic chemistry ,General Materials Science ,Biomass ,Char ,Lewis acids and bases ,010405 organic chemistry ,Chemistry ,Hydrogen-Ion Concentration ,Silicon Dioxide ,0104 chemical sciences ,Kinetics ,Mesoporous organosilica ,General Energy ,Chemical engineering ,Aluminum Silicates ,Mesoporous material ,Selectivity ,Porosity ,Pyrolysis - Abstract
Catalytic fast pyrolysis (CFP) of lignin with amorphous mesoporous aluminosilicates catalysts yields a high fraction of aromatics and a relatively low amount of char/coke. The relationship between the acidity and porosity of Al-MCM-41, Al-SBA-15, and Al-MSU-J with product selectivity during lignin CFP is determined. The acid sites (mild Brønsted and stronger Lewis) are able to catalyze pyrolysis intermediates towards fewer oxygenated phenols and aromatic hydrocarbons. A generalized correlation of the product selectivity and yield with the aluminum content and acidity of the mesoporous aluminosilicates is hard to establish. Zeolitic strong acid sites are not required to achieve high conversion and selectivity to aromatic hydrocarbon because nanosized MCM-41 produces a high liquid yield and selectivity. The two most essential parameters are diffusion, which is influenced by pore and grain size, and the active site, which may be mildly acidic, but is dominated by Lewis acid sites. Nanosized grains and mild acidity are essential ingredients for a good lignin CFP catalyst.
- Published
- 2016
31. Glucose to Fructose Isomerization in Aqueous Media over Homogeneous and Heterogeneous Catalysts
- Author
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Eleni F. Iliopoulou, Chrysoula M. Michailof, Asimina A. Marianou, Antonio Pineda, Kostas S. Triantafyllidis, and Angelos A. Lappas
- Subjects
Sodium aluminate ,010405 organic chemistry ,Organic Chemistry ,Inorganic chemistry ,Biomass ,Fructose ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Yield (chemistry) ,Organic chemistry ,Lewis acids and bases ,Physical and Theoretical Chemistry ,Selectivity ,Isomerization - Abstract
Isomerization of glucose to fructose is an important reaction with numerous applications in terms of biomass valorization. The reaction is catalyzed enzymatically but may also proceed under alkaline conditions, in which case it is accompanied by low selectivity and formation of byproducts. Solid Lewis acid and basic catalytic materials are being studied as alternative catalysts. In this work, the isomerization of glucose to fructose in aqueous media over homogeneous and heterogeneous catalysts has been investigated. The effect of polar aprotic solvents and their mixtures with water on glucose conversion and fructose selectivity was also studied. Sodium aluminate (NaAlO2) has been proven to be very effective, resulting in high fructose yield (52.1 %) and high selectivity (84.8 %). Among the various solid catalysts tested, MgO afforded glucose conversion of 44 %, with 75.8 % and 33.4 % fructose selectivity and yield, respectively, when the isomerization reaction was conducted in neat H2O.
- Published
- 2016
32. d -Glucose hydrogenation/hydrogenolysis reactions on noble metal (Ru, Pt)/activated carbon supported catalysts
- Author
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Vasile I. Parvulescu, Simona M. Coman, Stamatia A. Karakoulia, Andreas Delimitis, Polykarpos A. Lazaridis, and Kostas S. Triantafyllidis
- Subjects
Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,engineering.material ,Catalysis ,Ruthenium ,chemistry.chemical_compound ,chemistry ,Hydrogenolysis ,engineering ,Sorbitol ,Noble metal ,Platinum ,Selectivity ,Threitol ,Nuclear chemistry - Abstract
In the present work we studied the hydrogenation/hydrogenolysis of d -glucose over Pt and Ru catalysts supported on activated micro/mesoporous carbon (AC), under low hydrogen pressure (1.6 MPa) and relatively high reaction temperature, i.e. 180 °C. We also studied the effect of metal content (1–5 wt.%), method of metal pre-treatment/reduction (H 2 at 350 °C or NaBH 4 ) and reaction time (1–12 h). All the Ru and Pt/AC catalysts were very active (conversion ≥97%) with the Pt/AC catalysts being also very selective toward sorbitol (sel. ≥90%) irrespective of metal content, method of reduction and reaction time (up to 12 h). On the other hand, the Ru/AC catalysts exhibited a wide range of sorbitol selectivity values (55–93%) having various C 3 –C 6 sugar alcohols (1,2,5,6-hexanetetrol, arabinitol, threitol, glycerol and 1,2-propanediol) as main by-products. The formation of by-products was dependent on the crystalline/amorphous nature of Ru and Ru(O) x δ + nanoparticles which were in turn affected by the Ru content and the method of reduction.
- Published
- 2015
33. Overview of catalytic upgrading of biomass pyrolysis vapors toward the production of fuels and high‐value chemicals
- Author
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Eleni F. Iliopoulou, Kostas S. Triantafyllidis, and Angelos A. Lappas
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Biomass ,02 engineering and technology ,Renewable fuels ,Coke ,Raw material ,021001 nanoscience & nanotechnology ,Heterogeneous catalysis ,Catalysis ,Chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,0210 nano-technology ,Mesoporous material ,Pyrolysis ,General Environmental Science - Abstract
The application of heterogeneous catalysis in biomass pyrolysis is considered as one of the most promising methods to improve bio‐oil quality by minimizing its undesirable properties (high viscosity, corrosivity, instability, etc.) and producing renewable fuels and high‐value chemicals. Catalytic fast pyrolysis (CFP) of biomass refers both to the “in situ” and “ex situ or two‐stage” upgrading. A plethora of catalytic materials have been investigated in the literature for both approaches, including conventional microporous zeolites, ordered mesoporous aluminosilicates, promoted or not with several transition metals, as well as various metal (nano)oxide catalysts with Lewis acidity. Recently, hybrid micro/mesoporous and basic materials have been also suggested exhibiting most promising results due to combined micro/mesoporosity and adequate balance of acid and basic sites. Optimum catalysts are required to retain deoxygenation, enhance yields of aromatics, and other valuable compounds (such as phenolics), while limiting coke formation. Coke formation is one of the reasons of catalyst deactivation; a very challenging issue during biomass CFP, especially using zeolites. The deactivation process is affected by many factors, including the composition of the feedstock (inorganic minerals present in the feedstock may also deposit on the catalyst), reaction conditions, and the nature/properties of the catalysts used in CFP. Precoking on the surface of zeolites or MgO deposition are among the proposed effective ways to suppress coke formation and thus, catalyst deactivation. This article is categorized under: Bioenergy > Science and Materials Energy Research & Innovation > Science and Materials Energy and Transport > Science and Materials
- Published
- 2018
34. Efficient vegetative propagation of various clones of mastic tree (Pistacia lentiscus ‘Chia’) through rooting of shoot cuttings
- Author
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Kostas, S., primary, Hatziloukas, E., additional, Hatzilazarou, S., additional, and Economou, A.S., additional
- Published
- 2019
- Full Text
- View/download PDF
35. Genotypic tolerance of two Punica granatum L. cultivars (‘Wonderful’ and ‘Acco’) to serpentine stress
- Author
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Chatzistathis, T., primary, Papadakis, I.E., additional, Papaioannou, A., additional, Dichala, O., additional, Giannakoula, A., additional, Kostas, S., additional, and Tziachris, P., additional
- Published
- 2019
- Full Text
- View/download PDF
36. Effect of graphene oxide and its modification on the microstructure, thermal properties and enzymatic hydrolysis of poly(ethylene succinate) nanocomposites
- Author
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Vasilios Tsanaktsis, Zoe Terzopoulou, George Z. Papageorgiou, Kostas S. Triantafyllidis, Evmorfia K. Diamanti, Dimitrios Gournis, Dimitrios N. Bikiaris, and Dimitris S. Achilias
- Subjects
Materials science ,Nanocomposite ,Graphene ,Oxide ,Condensed Matter Physics ,Biodegradable polymer ,law.invention ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,law ,Poly(ethylene succinate) ,Enzymatic hydrolysis ,Polymer chemistry ,Physical and Theoretical Chemistry ,Crystallization ,Fourier transform infrared spectroscopy ,Instrumentation - Abstract
In this work, two series of biodegradable nanocomposites of poly(ethylene succinate) (PESu) containing either graphene oxide (GO) or organomodified GO (org-GO) with 1-dodecylamine have been prepared and studied. GO was synthesized using a modified Staudenmaier method from of powdered graphite and PESu/GO and PESu/org-GO nanocomposites with GO or org-GO concentrations 0.5, 1 or 2.5 wt% were prepared with the solvent evaporation method. The nanocomposites were characterized with several techniques. Microscopic and XRD study showed intercalated dispersion of GO into PESu matrix while in the case of org-GO fully exfoliated nanocomposites were obtained. Isothermal and nonisothermal crystallization was studied from the melt or from the glass state by using DSC and it was found that nanocomposites crystallized faster than the neat PESu under both conditions. Crystallization rates increased with increasing filler content and it seems that GO have higher crystallisation effect than org-GO. This is due to the stronger interactions that are taking place between PESu and GO, as was confirmed by FTIR and DSC. In the case of the nanocomposites interesting crystalline morphologies and different to those for neat PESu were observed with PLM. Enzymatic hydrolysis studies revealed that nanocomposites have higher hydrolysis rates than neat PESu, while GO accelerates in higher extent the hydrolysis of PESu than org-GO.
- Published
- 2015
37. Effect of maleic anhydride on the mechanical and thermal properties of hemp/high-density polyethylene green composites
- Author
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Eleni Pavlidou, Dimitrios N. Bikiaris, Electra Papadopoulou, Konstantinos Chrissafis, Kostas S. Triantafyllidis, Eleftheria Athanasiadou, Eleftheria Roumeli, and Zoe Terzopoulou
- Subjects
Materials science ,Maleic anhydride ,Polyethylene ,Condensed Matter Physics ,Thermogravimetry ,chemistry.chemical_compound ,Crystallinity ,Differential scanning calorimetry ,chemistry ,Ultimate tensile strength ,Thermal stability ,High-density polyethylene ,Physical and Theoretical Chemistry ,Composite material - Abstract
In the present work, the effective use of polyethylene-grafted maleic anhydride (PE-g-MA) copolymer as a compatibilizer in high-density polyethylene composites containing 10–50 mass% hemp fibers was evaluated through mechanical and thermal properties measurements. The results revealed a significant reinforcement on the tensile strength of the composites as a consequence of the incorporation of the compatibilizer. Less pronounced effects were found on the elongation at break and impact strength of the composites. The notable enhancement of tensile strength on the compatibilized composites was related to the improved adhesion of hemp with the matrix in the presence of PE-g-MA, which was revealed through scanning electron microscopy observations. Furthermore, Fourier transform infrared spectroscopy analyses suggested that covalent bonding occurs between the fibers and the matrix in the highest PE-g-MA concentrations. Differential scanning calorimetry experiments revealed that the presence of compatibilizer increases the crystallinity of the composites. Thermogravimetry studies revealed that for low compatibilizer concentrations the thermal stability of the composites is further reduced, while for the highest concentration, when bonding occurs, it is enhanced. The biodegradation studies of all the composites revealed that the incorporation of compatibilizer enhances the stability of the composites, especially in the higher concentrations, and reduces their final residue.
- Published
- 2015
38. K-promoted NiMo catalysts supported on activated carbon for the hydrogenation reaction of CO to higher alcohols: Effect of support and active metal
- Author
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Kostas S. Triantafyllidis, Eleni Heracleous, E.T. Liakakou, and Angeliki A. Lemonidou
- Subjects
Aqueous solution ,Chemistry ,Process Chemistry and Technology ,Inorganic chemistry ,Catalysis ,Metal ,Crystallinity ,visual_art ,medicine ,visual_art.visual_art_medium ,Selectivity ,Bimetallic strip ,Oxygenate ,General Environmental Science ,Activated carbon ,medicine.drug - Abstract
This study investigates the effect of active metal and the nature and pre-treatment of the support in a series of K-promoted NiMo catalysts supported on activated carbon (AC) for the hydrogenation reaction of CO. The Ni Mo synergistic effect was found to be essential for the activation of CO. The use of activated carbon as support led to a three-fold increase in the selectivity toward higher alcohols, compared to the unsupported material, probably due to a reduction in the crystallinity of the active NiMoO4 phase and its partial transformation from alpha to beta form. Pre-treatment of the activated carbon prior to its use as support with HNO3 aqueous solution led to significant increase in CO conversion, related to the lower amount of ash and the much higher acidity of the acid treated sample. The use of a higher surface area acid-treated support also increases activity, with the K NiMo/AC2a catalyst exhibiting a 45% higher conversion at 280 °C compared to K NiMo/AC1a. The improvement in activity can be ascribed to better dispersion of the active phase on the higher surface area AC support and therefore higher exposure of active Ni O Mo sites. Overall, the K NiMo/AC2a catalyst exhibited the optimum performance, with high CO conversion (25% at 280 °C) and high production of oxygenates, with a space time yield to oxygenates of 141.5 mg/gcatalyst/h at 280 °C. A clear tendency of increasing higher alcohol production with decreasing acidity was evidenced for all K-promoted bimetallic NiMo catalysts.
- Published
- 2015
39. Effect of organoclays type on solid-state polymerization (SSP) of poly(ethylene terephthalate): Experimental and modeling
- Author
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Eva Karandrea, Kostas S. Triantafyllidis, Athanasios K. Ladavos, Dimitrios N. Bikiaris, and Dimitris S. Achilias
- Subjects
chemistry.chemical_classification ,Materials science ,Nanocomposite ,Condensation polymer ,Polymers and Plastics ,Intrinsic viscosity ,Organic Chemistry ,General Physics and Astronomy ,Transesterification ,Polymer ,complex mixtures ,Exfoliation joint ,Amorphous solid ,chemistry ,Polymerization ,Chemical engineering ,Polymer chemistry ,Materials Chemistry - Abstract
In the current study the effect of different clay type, as well as clay organomodifier, on solid state polymerization (SSP) of poly(ethylene terephthalate) (PET) was investigated. PET/clay nanocomposites containing Nanomer I.30E, Cloisite 10A and Laponite have been prepared by melt mixing and their structure was studied by X-ray diffraction measurements. Solid state was conducted at 220, 230 and 240 °C for 1, 2, 3 and 4 h under vacuum application. The I.30E organo-clay exhibited the higher immobilized amorphous fraction. This is due to its better dispersion and exfoliation of the clay nanolayers into the PET matrix, compared to the other organoclays. Intrinsic viscosity (IV) measurements after solid-state polymerization of nanocomposites revealed that IV increase is time and temperature dependent. However, nanocomposites exhibited much lower IV increase compared with neat PET. A simple kinetic model was employed to predict the time evolution of IV, as well as the carboxyl and hydroxyl content during SSP. From the experimental measurements and the theoretical simulation results it was proved that the higher aspect ratio of the nano-clay added, leads to higher inactivated hydroxyls end-groups concentration, higher activation energies and lower transesterification and esterification kinetic rate constants. Increased dispersion of the clay nanolayers in the polymer matrix in addition to increased aspect ratio, leads to better gas barrier properties, reducing the diffusivity and thus the removal of the polycondensation byproducts, i.e. water and EG.
- Published
- 2015
40. Catalytic and thermal pyrolysis of polycarbonate in a fixed-bed reactor: The effect of catalysts on products yields and composition
- Author
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Angelos A. Lappas, Kostas S. Triantafyllidis, Stylianos D. Stefanidis, Dimitris S. Achilias, Konstantinos G. Kalogiannis, E.V. Antonakou, and Stamatia A. Karakoulia
- Subjects
Materials science ,Polymers and Plastics ,business.industry ,Chemical industry ,Condensed Matter Physics ,Catalysis ,chemistry.chemical_compound ,Monomer ,chemistry ,Chemical engineering ,Mechanics of Materials ,visual_art ,Scientific method ,Materials Chemistry ,visual_art.visual_art_medium ,Organic chemistry ,Degradation (geology) ,Polycarbonate ,Porosity ,business ,Pyrolysis - Abstract
A meaningful and advanced method concerning the management of waste electrical and electronic equipment (WEEE) becomes a necessity, mainly due to their increased production, applications and their short life. Thermal methods have been an attractive option and for this reason the investigation of pyrolysis and catalytic pyrolysis as a potential method for the recycling of polycarbonate (PC) based plastics has been the aim of the current study. Nine different catalysts with variations in properties (such as porosity and acidity/basicity) were introduced in a bench scale pyrolysis system together with the polycarbonate polymeric material and the pyrolysis fractions were collected and analyzed. The liquid product consisted mainly of phenols and substituted phenols as well as the original monomer and, due to the commercial value of these products in the chemical industry, it is expected to enhance the economic viability of the process. Results showed a reduction in the degradation temperature in the presence of all catalytic materials, depending on the pore characteristics and the acidic nature of the solid. It seems that in the presence of the basic catalysts, PC degradation leads to lower molecular weight compounds and high phenolic fractions in the liquid produced. In terms of reduction in the production of the monomer, pore size rather than acidity appears to be the determining factor.
- Published
- 2014
41. Nanocatalysis in the Fast Pyrolysis of Lignocellulosic Biomass
- Author
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Eleni F. Iliopoulou, Polykarpos A. Lazaridis, and Kostas S. Triantafyllidis
- Subjects
Chemical engineering ,010405 organic chemistry ,Chemistry ,Condensation ,Aromatization ,Lignocellulosic biomass ,010402 general chemistry ,01 natural sciences ,Deoxygenation ,Pyrolysis ,0104 chemical sciences - Published
- 2017
42. Esterification of free fatty acids using acidic metal oxides and supported polyoxometalate (POM) catalysts
- Author
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Stamatia A. Karakoulia, Kostas S. Triantafyllidis, Nicoletta Ravasio, K. Avramidou, and Federica Zaccheria
- Subjects
Esterification ,010405 organic chemistry ,Chemistry ,Process Chemistry and Technology ,Inorganic chemistry ,Heteropoly acids and polyoxometalates (POM) ,010402 general chemistry ,Free fatty acids ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Oleic acid ,Aluminosilicate ,Meso/macroporous oxides and aluminosilicates ,Polyoxometalate ,Pyridine ,BioLubricants ,Polyols ,Reactivity (chemistry) ,Physical and Theoretical Chemistry ,Trimethylolpropane ,Selectivity - Abstract
The valorization of various types of low-quality vegetable oils with relatively high content of free fatty acids (FFA) is a research field of increased interest. The esterification of oleic acid, a highly abundant FFA in waste oils, with trimethylolpropane (TMP) towards the production of the corresponding triesters, which can be used in lubricants or hydraulic fluids, was studied in this work. The catalysts tested were various meso/macroporous oxides, such as ZrO2, 3.5%SiO2-ZrO2, SiO2-Al2O3, SBA-15 and Al-SBA-15 with varying textural and acidic properties and the corresponding supported heteropoly acid catalysts, prepared by the use of phosphotungstic (H3PW12O40) and tungstosilicic (H4SiW12O40) acids. The catalysts were characterized by ICP-AES, XRD, FT-IR, N-2 porosimetry and FT-IR coupled with pyridine adsorption. The main product at 200 degrees C and after 6 h of reaction was the triester (TE) of oleic acid with selectivity values ranging from 85% to 99% at conversion degrees of 82% to 96%. The two aluminosilicate catalysts that combine Bronsted and Lewis acidity (i.e. SiO2-Al2O3 and Al-SBA-15) showed slightly higher yields of triester (similar to 83%) compared to the rest oxides (similar to 78%), while the Bronsted acidity induced by the two heteropoly acids, especially by PW, provided very high reactivity and selectivity towards triesters, irrespective of the type of support used, reaching triester yield values of 95% (96.2% conversion, 98.7% selectivity) with the 20%PW/ZrO2 catalyst, The most stable catalysts against leaching of heteropoly acids were those supported on 3.5%SiO2-ZrO2 and SiO2-Al2O3. (C) 2017 Elsevier B.V. All rights reserved.
- Published
- 2017
- Full Text
- View/download PDF
43. Overview of catalytic upgrading of biomass pyrolysis vapors toward the production of fuels and high‐value chemicals
- Author
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Iliopoulou, Eleni F., primary, Triantafyllidis, Kostas S., additional, and Lappas, Angelos A., additional
- Published
- 2018
- Full Text
- View/download PDF
44. Catalytic Pyrolysis of Biomass for Transportation Fuels
- Author
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Angelos A. Lappas, Kostas G. Kalogiannis, Eleni F. Iliopoulou, Kostas S. Triantafyllidis, and Stylianos D. Stefanidis
- Published
- 2015
45. The future of the Brazilian resettlement programme
- Author
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Silva Menezes, T and Kostas, S
- Subjects
internal displacement ,lcsh:HN1-995 ,forced migration ,criminal gangs ,IDP ,refugee ,Brazil Declaration ,stateless ,lcsh:Social history and conditions. Social problems. Social reform ,migration - Abstract
Brazil’s resettlement programmes have been praised for demonstrating the country’s commitment to refugee protection but the number resettled remains small compared with international need. Brazil needs to address the financing of such programmes if it is to ensure their sustainability and growth.
- Published
- 2017
46. Effect of crystal orientation and nanofiller alignment on dielectric breakdown of polyethylene/montmorillonite nanocomposites
- Author
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Li, Bo, primary, Xidas, Panagiotis I., additional, Triantafyllidis, Kostas S., additional, and Manias, Evangelos, additional
- Published
- 2017
- Full Text
- View/download PDF
47. Selective Reduction of Azines to Benzyl Hydrazones with Sodium Borohydride Catalyzed by Mesoporous Silica-Supported Silver Nanoparticles: A Catalytic Route towards Pyrazole Synthesis
- Author
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Charistoudi, Evangelia, primary, Kallitsakis, Michael G., additional, Charisteidis, Ioannis, additional, Triantafyllidis, Kostas S., additional, and Lykakis, Ioannis N., additional
- Published
- 2017
- Full Text
- View/download PDF
48. The IASLC Lung Cancer Staging Project: External Validation of the Revision of the TNM Stage Groupings in the Eighth Edition of the TNM Classification of Lung Cancer
- Author
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Chansky, Kari, primary, Detterbeck, Frank C., additional, Nicholson, Andrew G., additional, Rusch, Valerie W., additional, Vallières, Eric, additional, Groome, Patti, additional, Kennedy, Catherine, additional, Krasnik, Mark, additional, Peake, Michael, additional, Shemanski, Lynn, additional, Bolejack, Vanessa, additional, Crowley, John J., additional, Asamura, Hisao, additional, Rami-Porta, Ramón, additional, Goldstraw, Peter, additional, Ball, David, additional, Beer, David G., additional, Beyruti, Ricardo, additional, Chansky, Kari, additional, Crowley, John, additional, Detterbeck, Frank, additional, Erich Eberhardt, Wilfried Ernst, additional, Edwards, John, additional, Galateau-Sallé, Françoise, additional, Giroux, Dorothy, additional, Gleeson, Fergus, additional, Huang, James, additional, Kim, Jhingook, additional, Kim, Young Tae, additional, Kingsbury, Laura, additional, Kondo, Haruhiko, additional, Kubota, Kaoru, additional, Lerut, Antoon, additional, Lyons, Gustavo, additional, Marino, Mirella, additional, Marom, Edith M., additional, van Meerbeeck, Jan, additional, Mitchell, Alan, additional, Nakano, Takashi, additional, Nowak, Anna, additional, Rice, Thomas, additional, Rosenzweig, Kenneth, additional, Ruffini, Enrico, additional, Rusch, Valerie, additional, Saijo, Nagahiro, additional, Van Schil, Paul, additional, Sculier, Jean-Paul, additional, Stratton, Kelly, additional, Suzuki, Kenji, additional, Tachimori, Yuji, additional, Thomas, Charles F., additional, Travis, William, additional, Tsao, Ming S., additional, Turrisi, Andrew, additional, Vansteenkiste, Johan, additional, Watanabe, Hirokazu, additional, Wu, Yi-Long, additional, Baas, Paul, additional, Erasmus, Jeremy, additional, Hasegawa, Seiki, additional, Inai, Kouki, additional, Kernstine, Kemp, additional, Kindler, Hedy, additional, Krug, Lee, additional, Nackaerts, Kristiaan, additional, Pass, Harvey, additional, Rice, David, additional, Falkson, Conrad, additional, Filosso, Pier Luigi, additional, Giaccone, Giuseppe, additional, Kondo, Kazuya, additional, Lucchi, Marco, additional, Okumura, Meinoshin, additional, Blackstone, Eugene, additional, Cavaco, F. Abad, additional, Barrera, E. Ansótegui, additional, Arca, J. Abal, additional, Lamelas, I. Parente, additional, Obrer, A. Arnau, additional, Jorge, R. Guijarro, additional, Ball, D., additional, Bascom, G.K., additional, Orozco, A. I. Blanco, additional, Castro, M. A. González, additional, Blum, M.G., additional, Chimondeguy, D., additional, Cvijanovic, V., additional, Defranchi, S., additional, de Olaiz Navarro, B., additional, Campuzano, I. Escobar, additional, Vidueira, I. Macía, additional, Araujo, E. Fernández, additional, García, F. Andreo, additional, Fong, K.M., additional, Corral, G. Francisco, additional, González, S. Cerezo, additional, Gilart, J. Freixinet, additional, Arangüena, L. García, additional, Barajas, S. García, additional, Girard, P., additional, Goksel, T., additional, Budiño, M. T. González, additional, Casaurrán, G. González, additional, Blanco, J. A. Gullón, additional, Hernández, J. Hernández, additional, Rodríguez, H. Hernández, additional, Collantes, J. Herrero, additional, Heras, M. Iglesias, additional, Elena, J. M. Izquierdo, additional, Jakobsen, E., additional, Kostas, S., additional, Atance, P. León, additional, Ares, A. Núñez, additional, Liao, M., additional, Losanovscky, M., additional, Lyons, G., additional, Magaroles, R., additional, De Esteban Júlvez, L., additional, Gorospe, M. Mariñán, additional, McCaughan, B., additional, Kennedy, C., additional, Íñiguez, R. Melchor, additional, Sorribes, L. Miravet, additional, Gozalo, S. Naranjo, additional, Álvarez de Arriba, C., additional, Delgado, M. Núñez, additional, Alarcón, J. Padilla, additional, Cuesta, J. C. Peñalver, additional, Park, J.S., additional, Pass, H., additional, Fernández, M. J. Pavón, additional, Rosenberg, M., additional, Ruffini, E., additional, Rusch, V., additional, Sánchez de Cos Escuín, J., additional, Vinuesa, A. Saura, additional, Mitjans, M. Serra, additional, Strand, T.E., additional, Subotic, D., additional, Swisher, S., additional, Terra, R., additional, Thomas, C., additional, Tournoy, K., additional, Van Schil, P., additional, Velasquez, M., additional, Wu, Y.L., additional, and Yokoi, K., additional
- Published
- 2017
- Full Text
- View/download PDF
49. Mesoporous Zeolite Catalysts for Biomass Conversion to Fuels and Chemicals
- Author
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Christos Nitsos, Stamatia A. Karakoulia, Angelos A. Lappas, Eleni F. Iliopoulou, and Kostas S. Triantafyllidis
- Subjects
Biodiesel ,Materials science ,Biofuel ,Organic chemistry ,Lignocellulosic biomass ,Biomass ,Mesoporous material ,Zeolite ,Hydrodeoxygenation ,Catalysis - Published
- 2015
50. Activated carbons for the removal of heavy metal ions: A systematic review of recent literature focused on lead and arsenic ions
- Author
-
Kostas S. Triantafyllidis, Kostas A. Matis, George Z. Kyzas, and Eleni A. Deliyanni
- Subjects
lead ,Chemistry ,Metal ions in aqueous solution ,Inorganic chemistry ,arsenic ,General Chemistry ,Microporous material ,Adsorption ,adsorption ,Materials Chemistry ,medicine ,Surface modification ,Fourier transform infrared spectroscopy ,Mesoporous material ,QD1-999 ,wastewaters ,Activated carbon ,medicine.drug ,BET theory - Abstract
This work is a systematic review of the literature over the past decade of the application of activated carbon (microporous or mesoporous) as adsorbents for the removal of heavy metals, focusing especially on lead (Pb) and arsenic (As) ions from the aqueous phase. Classical examples from our lab are also given. Activated carbon is known to provide a high surface area for adsorption. Generally, surface modification is typically required, such as oxidation, treatment with ammonia or even impregnation with ferric ion, etc. and the adsorbent material may originate from various sources. The pristine materials, after modification and those after batch-wise adsorption, were characterized by available techniques (BET analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, thermal analyses, X-ray photoelectron spectroscopy). Adsorption isotherms, thermodynamics and kinetics of the process are also discussed. Selected studies from the literature are examined in comparison with other adsorbents. The role of chemistry in the metals adsorption/removal was investigated.
- Published
- 2015
Catalog
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