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Börjesson, A.
Alternativa namn
Publikasjoner (10 av 16) Visa alla publikasjoner
Börjesson, A., Erdtman, E., Ahlström, P., Berlin, M., Andersson, T. & Bolton, K. (2013). Molecular modelling of oxygen and water permeation in polyethylene. Polymer, 54(12), 2988
Åpne denne publikasjonen i ny fane eller vindu >>Molecular modelling of oxygen and water permeation in polyethylene
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2013 (engelsk)Inngår i: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 54, nr 12, s. 2988-Artikkel i tidsskrift (Fagfellevurdert)
Abstract [en]

Monte Carlo and molecular dynamics simulations were performed to calculate solubility, S, and diffusion, D, coefficients of oxygen and water in polyethylene, and to obtain a molecular-level understanding of the diffusion mechanism. The permeation coefficient, P, was calculated from the product of S and D. The AMBER force field, which yields the correct polymer densities under the conditions studied, was used for the simulations, and it was observed that the results were not sensitive to the inclusion of atomic charges in the force field. The simulated S for oxygen and water are higher and lower than experimental data, respectively. The calculated diffusion coefficients are in good agreement with experimental data. Possible reasons for the discrepancy in the simulated and experimental solubilities, which results in discrepancies in the permeation coefficients, are discussed. The diffusion of both penetrants occurs mainly by large amplitude, infrequent jumps of the molecules through the polymer matrix.

sted, utgiver, år, opplag, sider
Elsevier, 2013
Emneord
Permeability, Polyethylene, Molecular simulation, Resursåtervinning, Computational modelling
HSV kategori
Forskningsprogram
Resursåtervinning
Identifikatorer
urn:nbn:se:hb:diva-1569 (URN)10.1016/j.polymer.2013.03.065 (DOI)000319365900020 ()2320/12338 (Lokal ID)2320/12338 (Arkivnummer)2320/12338 (OAI)
Merknad

Sponsorship:

KK-stiftelsen

Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2019-12-13
Bolton, K. & Börjesson, A. (2011). Computational studies of single-walled carbon nanotube growth. SNIC Progress Report (2008-2009), 40-46
Åpne denne publikasjonen i ny fane eller vindu >>Computational studies of single-walled carbon nanotube growth
2011 (engelsk)Inngår i: SNIC Progress Report (2008-2009), s. 40-46Artikkel i tidsskrift (Annet vitenskapelig) Published
Abstract [en]

Allocation of time on the Swedish national supercomputing facilities since 2000, as well as support from other sources, has allowed us to perform computational studies on a wide variety of systems. These include properties and growth of carbon nanotubes [1–36], icecatalysed reactions of importance to stratospheric ozone depletion[37], calculations of vapour-liquid, liquid-liquid and vapour-liquid-liquid phase equilibrium of single, binary and ternary component systems[38], and, more recently, carbonaceous polymer nanocomposites and cellulose decomposition. More details of these projects are available at the web page given above.

sted, utgiver, år, opplag, sider
Swedish National Infrastructure for Computing, 2011
Emneord
carbon nanotubes, growth, modelling, Energi och material
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-3269 (URN)2320/9925 (Lokal ID)2320/9925 (Arkivnummer)2320/9925 (OAI)
Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2018-02-25bibliografisk kontrollert
Börjesson, A. & Bolton, K. (2011). First Principles Studies of the Effect of Ostwald Ripening on Carbon Nanotube Chirality Distributions. ACS Nano, 5(2), 771-779
Åpne denne publikasjonen i ny fane eller vindu >>First Principles Studies of the Effect of Ostwald Ripening on Carbon Nanotube Chirality Distributions
2011 (engelsk)Inngår i: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 5, nr 2, s. 771-779Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The effect of Ostwald ripening of metal particles attached to carbon nanotubes has been studied using density functional theory. It has been confirmed that Ostwald ripening may be responsible for the termination of growth of carbon nanotube forests. It was seen that the Ostwald ripening of metal particles attached to carbon nanotubes is governed by a critical factor that depends on both the cluster size and the carbon nanotube chirality. For example, clusters attached to armchair and zigzag nanotubes of similar diameters will have different critical factors although the exact behavior may depend on which molecules are present in the surrounding medium. The critical factor was also observed to have a critical point with the effect that clusters with a narrow size distribution close to the critical point may experience a narrowing rather than a widening of the size distribution, as is the case for free clusters.

sted, utgiver, år, opplag, sider
American Chemical Society, 2011
Emneord
carbon nanotube, ni nanoparticle, density functional theory, molecular dynamics, molecular dynamics, growth density, functional theory, ostwald ripening, Energi och material
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-3080 (URN)10.1021/nn101214v (DOI)2320/8000 (Lokal ID)2320/8000 (Arkivnummer)2320/8000 (OAI)
Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2017-11-16bibliografisk kontrollert
Börjesson, A. & Bolton, K. (2011). Modelling of Ostwald ripening of metal clusters attached to carbon nanotubes. The Journal of Physical Chemistry C, 115(50), 24454-24462
Åpne denne publikasjonen i ny fane eller vindu >>Modelling of Ostwald ripening of metal clusters attached to carbon nanotubes
2011 (engelsk)Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 115, nr 50, s. 24454-24462Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We present a model of Ostwald ripening of nanosized clusters and apply it to study the time evolution of metal particles attached to carbon nanotubes. The Ostwald ripening of metal clusters attached to carbon nanotubes differs from that of free metal clusters. While free clusters experience a rapid broadening in the size dispersion, this may be delayed by the nanotubes, which may therefore limit the ripening. The diameter and chirality of the carbon nanotubes were also seen to affect the Ostwald ripening of the catalyst particles. For a collection of carbon nanotubes that contains different diameters and chiralities, the clusters attached to carbon nanotubes with large diameters and strong carbon–metal adhesion are the most likely to survive the Ostwald ripening.

sted, utgiver, år, opplag, sider
American Chemical Society, 2011
Emneord
carbon nanotubes, ostwald ripening, Energi och material
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-3274 (URN)10.1021/jp202328w (DOI)2320/9953 (Lokal ID)2320/9953 (Arkivnummer)2320/9953 (OAI)
Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2017-12-25bibliografisk kontrollert
Zhu, W., Börjesson, A. & Bolton, K. (2010). DFT and tight binding Monte Carlo calculations related to single-walled carbon nanotube nucleation and growth. Carbon, 48(2), 470-478
Åpne denne publikasjonen i ny fane eller vindu >>DFT and tight binding Monte Carlo calculations related to single-walled carbon nanotube nucleation and growth
2010 (engelsk)Inngår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 48, nr 2, s. 470-478Artikkel i tidsskrift (Fagfellevurdert)
Abstract [en]

Density-functional theory (DFT) calculations for idealized nucleation processes of (5,5) and (10,0) single-walled carbon nanotubes (SWCNTs) on a 55 atom nickel cluster (Ni-55) showed that it requires a larger chemical potential to grow a carbon island (which is the simplest structure that can lead to formation of the SWCNTs) on the cluster than to extend the island into a SWCNT or to have the carbon atoms dispersed on the cluster surface. Hence, in the thermodynamic limit the island will only form once the (surface of the) cluster is saturated with carbon, and the island will spontaneously form a SWCNT at the chemical potentials required to create the island. The DFT (zero Kelvin) and tight binding Monte Carlo (1000 K) also show that there is a minimum cluster size required to support SWCNT growth, and that this cluster size can be used to control the diameter, but probably not the chirality, of the SWCNT at temperatures relevant to carbon nanotube growth. It also imposes a minimum size of clusters that are used for SWCNT regrowth. (C) 2009 Elsevier Ltd. All rights reserved.

sted, utgiver, år, opplag, sider
Pergamon Elsevier, 2010
Emneord
carbon nanotube, computational modelling, Computational modelling
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-2662 (URN)10.1016/j.carbon.2009.09.064 (DOI)2320/5729 (Lokal ID)2320/5729 (Arkivnummer)2320/5729 (OAI)
Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2017-12-01
Börjesson, A. & Bolton, K. (2010). First Principles Studies of the Effect of Nickel Carbide Catalyst Composition on Carbon Nanotube Growth. The Journal of Physical Chemistry C, 114(42), 18045-18050
Åpne denne publikasjonen i ny fane eller vindu >>First Principles Studies of the Effect of Nickel Carbide Catalyst Composition on Carbon Nanotube Growth
2010 (engelsk)Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, nr 42, s. 18045-18050Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Density functional theory calculations were used to investigate the stability of single-walled carbon nanotubes (CNTs) attached to nanoparticles. The total energies and the adhesion energies between the CNTs and the nanoparticles were calculated for systems where the nanoparticles were either pure Ni or Ni carbide. It was found that the adhesion between the CNT and a pure Ni cluster is stronger than between the same CNT and a Ni carbide cluster although the energy difference was small compared to the total adhesion energies. This adhesion strength implies that CNTs are likely to remain attached to both pure Ni and Ni carbide clusters and that either pure Ni or Ni carbide clusters may be docked onto the open CNT ends to achieve continued growth or electronic contacts between CNTs and electrode materials. The system with a CNT attached to a pure Ni cluster was found to be energetically favored compared to a system containing the same CNT attached to a Ni carbide. The difference in total energy implies that a CNT should act as a sink for C atoms dissolved in the Ni carbide cluster, which means that the dissolved C atoms will be drained from the cluster, yielding a pure metal in the zero Kelvin thermodynamic limit. It is argued that this draining procedure is likely to occur even if carbon is added to the cluster at a proper rate, for example, during CNT growth.

sted, utgiver, år, opplag, sider
American Chemical Society, 2010
Emneord
datormodellering, Energi och material
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-2968 (URN)10.1021/jp1045707 (DOI)2320/7324 (Lokal ID)2320/7324 (Arkivnummer)2320/7324 (OAI)
Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2017-12-01bibliografisk kontrollert
Börjesson, A. (2010). In silico studies of carbon nano tubes and metal clusters. (Doctoral dissertation). Department of Physics, University of Gothenburg ; School of Engineering, University of Borås
Åpne denne publikasjonen i ny fane eller vindu >>In silico studies of carbon nano tubes and metal clusters
2010 (engelsk)Doktoravhandling, monografi (Annet vitenskapelig)
Abstract [en]

Carbon nanotubes have been envisioned to become a very important material in various applications. This is due to the unique properties of carbon nanotubes which can be exploited in applications on length scales spanning from the nano world to our macroscopic world. For example, the electronic properties of carbon nanotubes makes them utterly suitable for nano electronics while the strength of them makes them suitable for reinforcements in plastics. Both of these applications do however require... mer the ability for systematic production of carbon nanotubes with certain properties. This is called selective carbon nanotube growth and today this has not been achieved with total success. In the work presented in the thesis several different computational methods have been applied in our contribution to the systematic search for selective carbon nanotube growth. Put in a context of previous knowledge about carbon nanotube growth our results provide valuable clues to which parameters that control the carbon nanotube growth. In association with the latest results we even dare to, with all modesty, speculate about a plausible control mechanism. The studies presented in the thesis addressed different stages of carbon nanotube growth, spanning from the properties affecting the initiation of the growth to the parameters affecting the termination of the growth. In some more detail this included studies of the melting temperatures of nanoscaled metal clusters. The expected size dependence of the melting temperatures was confirmed and the melting temperatures of clusters on substrates were seen to depend both on the material and shape of the surface. As this constitute the premises prior to the carbon nanotube growth it was followed by studies of the interaction between carbon nanotubes and metal clusters of different size and constitution. This was done using different computational methods and at different temperatures. It soon became apparent that the clusters adapted to the carbon nanotube and not vice versa. This held true irrespectively of the constitution of the cluster, that is for both pure metal and metal carbide. It was also seen that there exist a minimum cluster size that prevent the carbon nanotube end from closing. Closure of the carbon nanotube end is likely to lead to the termination of the growth which lead to studies of other reasons for growth termination, e.g., Ostwald ripening of the catalyst particles. This was investigated with the result that the rate of the Ostwald ripening may depend on both the chirality and diameter of the carbon nanotubes. It is suggested that this may provide some answers to the controlled growth of carbon nanotubes.

sted, utgiver, år, opplag, sider
Department of Physics, University of Gothenburg ; School of Engineering, University of Borås, 2010
Serie
Skrifter från Högskolan i Borås, ISSN 0280-381X ; 26
Emneord
carbon nanotube, metal clusters, melting temperatures, nanotechnology, molecular dynamics, tight binding, density functional theory, monte carlo, Energi och material
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-3565 (URN)2320/6908 (Lokal ID)978-91-628-8204-4 (ISBN)2320/6908 (Arkivnummer)2320/6908 (OAI)
Merknad

Disputationen sker fredagen den 3 december 2010, kl. 10:15, Kollektorn, Kemivägen 9

Tilgjengelig fra: 2015-12-04 Laget: 2015-12-04 Sist oppdatert: 2016-07-13bibliografisk kontrollert
Björk, H., Lindecrantz, K., Ericsson, D., Sarv, H., Bolton, K., Börjesson, A., . . . Skrifvars, M. (2009). 20 år med Institutionen Ingenjörshögskolan: historik, nuläge och framtid. Högskolan i Borås
Åpne denne publikasjonen i ny fane eller vindu >>20 år med Institutionen Ingenjörshögskolan: historik, nuläge och framtid
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2009 (svensk)Rapport (Annet vitenskapelig)
sted, utgiver, år, opplag, sider
Högskolan i Borås, 2009
Serie
Vetenskap för profession: rapport, ISSN 1654-6520 ; 10
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-4430 (URN)2320/5703 (Lokal ID)978-91-85659-49-4 (ISBN)2320/5703 (Arkivnummer)2320/5703 (OAI)
Merknad

En jubileumsskrift

Tilgjengelig fra: 2015-12-17 Laget: 2015-12-17 Sist oppdatert: 2017-11-09bibliografisk kontrollert
Bolton, K., Börjesson, A., Ahlström, P. & Bazooyar, F. (2009). Beräkningsteknik. Vetenskap för profession (10), 63-68
Åpne denne publikasjonen i ny fane eller vindu >>Beräkningsteknik
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2009 (svensk)Inngår i: Vetenskap för profession, ISSN 1654-6520, nr 10, s. 63-68Artikkel i tidsskrift (Annet vitenskapelig) Published
sted, utgiver, år, opplag, sider
Högskolan i Borås, 2009
Emneord
Energi och material
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-2723 (URN)2320/5924 (Lokal ID)978-91-85659-49-4 (ISBN)2320/5924 (Arkivnummer)2320/5924 (OAI)
Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2018-01-16bibliografisk kontrollert
Börjesson, A., Zhu, W., Amara, H., Bichara, C. & Bolton, K. (2009). Computational studies of metal-carbon nanotube interfaces for regrowth and electronic transport. Nano letters (Print), 9(3), 1117-1120
Åpne denne publikasjonen i ny fane eller vindu >>Computational studies of metal-carbon nanotube interfaces for regrowth and electronic transport
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2009 (engelsk)Inngår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 9, nr 3, s. 1117-1120Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

First principles and tight binding Monte Carlo simulations show that junctions between single-walled carbon nanotubes (SWNTs) and nickel clusters are on the cluster surface, and not at subsurface sites, irrespective of the nanotube chirality, temperature, and whether the docking is gentle or forced. Gentle docking helps to preserve the pristine structure of the SWNT at the metal interface, whereas forced docking may partially dissolve the SWNT in the cluster. This is important for SWNT-based electronics and SWNT-seeded regrowth.

sted, utgiver, år, opplag, sider
American Chemical Society, 2009
Emneord
kolnanorör, datormodellering, Energi och material
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-2595 (URN)10.1021/nl8036245 (DOI)2320/5211 (Lokal ID)2320/5211 (Arkivnummer)2320/5211 (OAI)
Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2017-11-16bibliografisk kontrollert
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