1. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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2. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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4. |
- Glasbey, JC, et al.
(författare)
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- 2021
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swepub:Mat__t
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6. |
- Krasilnikov, A., et al.
(författare)
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Evidence of 9 Be + p nuclear reactions during 2ω CH and hydrogen minority ICRH in JET-ILW hydrogen and deuterium plasmas
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:2
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Tidskriftsartikel (refereegranskat)abstract
- The intensity of 9Be + p nuclear fusion reactions was experimentally studied during second harmonic (2ω CH) ion-cyclotron resonance heating (ICRH) and further analyzed during fundamental hydrogen minority ICRH of JET-ILW hydrogen and deuterium plasmas. In relatively low-density plasmas with a high ICRH power, a population of fast H+ ions was created and measured by neutral particle analyzers. Primary and secondary nuclear reaction products, due to 9Be + p interaction, were observed with fast ion loss detectors, γ-ray spectrometers and neutron flux monitors and spectrometers. The possibility of using 9Be(p, d)2α and 9Be(p, α)6Li nuclear reactions to create a population of fast alpha particles and study their behaviour in non-active stage of ITER operation is discussed in the paper.
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- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:1
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Forskningsöversikt (refereegranskat)
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13. |
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14. |
- Bombarda, F., et al.
(författare)
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Runaway electron beam control
- 2019
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 61:1
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Tidskriftsartikel (refereegranskat)
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29. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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30. |
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Overview of the JET results
- 2015
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 55:10
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Tidskriftsartikel (refereegranskat)
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31. |
- Romanelli, F, et al.
(författare)
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Overview of the JET results
- 2011
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9
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Tidskriftsartikel (refereegranskat)abstract
- Since the last IAEA Conference JET has been in operation for one year with a programmatic focus on the qualification of ITER operating scenarios, the consolidation of ITER design choices and preparation for plasma operation with the ITER-like wall presently being installed in JET. Good progress has been achieved, including stationary ELMy H-mode operation at 4.5 MA. The high confinement hybrid scenario has been extended to high triangularity, lower ρ*and to pulse lengths comparable to the resistive time. The steady-state scenario has also been extended to lower ρ*and ν*and optimized to simultaneously achieve, under stationary conditions, ITER-like values of all other relevant normalized parameters. A dedicated helium campaign has allowed key aspects of plasma control and H-mode operation for the ITER non-activated phase to be evaluated. Effective sawtooth control by fast ions has been demonstrated with3He minority ICRH, a scenario with negligible minority current drive. Edge localized mode (ELM) control studies using external n = 1 and n = 2 perturbation fields have found a resonance effect in ELM frequency for specific q95values. Complete ELM suppression has, however, not been observed, even with an edge Chirikov parameter larger than 1. Pellet ELM pacing has been demonstrated and the minimum pellet size needed to trigger an ELM has been estimated. For both natural and mitigated ELMs a broadening of the divertor ELM-wetted area with increasing ELM size has been found. In disruption studies with massive gas injection up to 50% of the thermal energy could be radiated before, and 20% during, the thermal quench. Halo currents could be reduced by 60% and, using argon/deuterium and neon/deuterium gas mixtures, runaway electron generation could be avoided. Most objectives of the ITER-like ICRH antenna have been demonstrated; matching with closely packed straps, ELM resilience, scattering matrix arc detection and operation at high power density (6.2 MW m-2) and antenna strap voltages (42 kV). Coupling measurements are in very good agreement with TOPICA modelling. © 2011 IAEA, Vienna.
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32. |
- Abel, I, et al.
(författare)
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Overview of the JET results with the ITER-like wall
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
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Tidskriftsartikel (refereegranskat)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
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33. |
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34. |
- Dunham, I, et al.
(författare)
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The DNA sequence of human chromosome 22
- 1999
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 402:6761, s. 489-495
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Tidskriftsartikel (refereegranskat)
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35. |
- Power, M. J., et al.
(författare)
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Changes in fire regimes since the Last Glacial Maximum : an assessment based on a global synthesis and analysis of charcoal data
- 2008
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Ingår i: Climate Dynamics. - : Springer Science and Business Media LLC. - 0930-7575 .- 1432-0894. ; 30:7-8, s. 887-907
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Tidskriftsartikel (refereegranskat)abstract
- Fire activity has varied globally and continuously since the last glacial maximum (LGM) in response to long-term changes in global climate and shorter-term regional changes in climate, vegetation, and human land use. We have synthesized sedimentary charcoal records of biomass burning since the LGM and present global maps showing changes in fire activity for time slices during the past 21,000 years (as differences in charcoal accumulation values compared to pre-industrial). There is strong broad-scale coherence in fire activity after the LGM, but spatial heterogeneity in the signals increases thereafter. In North America, Europe and southern South America, charcoal records indicate less-than-present fire activity during the deglacial period, from 21,000 to ∼11,000 cal yr BP. In contrast, the tropical latitudes of South America and Africa show greater-than-present fire activity from ∼19,000 to ∼17,000 cal yr BP and most sites from Indochina and Australia show greater-than-present fire activity from 16,000 to ∼13,000 cal yr BP. Many sites indicate greater-than-present or near-present activity during the Holocene with the exception of eastern North America and eastern Asia from 8,000 to ∼3,000 cal yr BP, Indonesia and Australia from 11,000 to 4,000 cal yr BP, and southern South America from 6,000 to 3,000 cal yr BP where fire activity was less than present. Regional coherence in the patterns of change in fire activity was evident throughout the post-glacial period. These complex patterns can largely be explained in terms of large-scale climate controls modulated by local changes in vegetation and fuel load.
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37. |
- Thoma, B, et al.
(författare)
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An international, interprofessional investigation of the self-reported podcast listening habits of emergency clinicians: A METRIQ Study
- 2020
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Ingår i: CJEM. - : Springer Science and Business Media LLC. - 1481-8043 .- 1481-8035. ; 22:1, s. 112-117
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Tidskriftsartikel (refereegranskat)abstract
- ObjectivesPodcasts are increasingly being used for medical education. A deeper understanding of usage patterns would inform both producers and researchers of medical podcasts. We aimed to determine how and why podcasts are used by emergency medicine and critical care clinicians.MethodsAn international interprofessional sample (medical students, residents, physicians, nurses, physician assistants, and paramedics) was recruited through direct contact and a multimodal social media (Twitter and Facebook) campaign. Each participant completed a survey outlining how and why they utilize medical podcasts. Recruitment materials included an infographic and study website.Results390 participants from 33 countries and 4 professions (medicine, nursing, paramedicine, physician assistant) completed the survey. Participants most frequently listened to medical podcasts to review new literature (75.8%), learn core material (75.1%), and refresh memory (71.8%). The majority (62.6%) were aware of the ability to listen at increased speeds, but most (76.9%) listened at 1.0 x (normal) speed. All but 25 (6.4%) participants concurrently performed other tasks while listening. Driving (72.3%), exercising (39.7%), and completing chores (39.2%) were the most common. A minority of participants used active learning techniques such as pausing, rewinding, and replaying segments of the podcast. Very few listened to podcasts multiple times.ConclusionsAn international cohort of emergency clinicians use medical podcasts predominantly for learning. Their listening habits (rarely employing active learning strategies and frequently performing concurrent tasks) may not support this goal. Further exploration of the impact of these activities on learning from podcasts is warranted.
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38. |
- George, T. S., et al.
(författare)
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Organic phosphorus in the terrestrial environment : a perspective on the state of the art and future priorities
- 2018
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Ingår i: Plant and Soil. - : Springer Netherlands. - 0032-079X .- 1573-5036. ; 427:1-2, s. 191-208
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Tidskriftsartikel (refereegranskat)abstract
- Background: The dynamics of phosphorus (P) in the environment is important for regulating nutrient cycles in natural and managed ecosystems and an integral part in assessing biological resilience against environmental change. Organic P (P-o) compounds play key roles in biological and ecosystems function in the terrestrial environment being critical to cell function, growth and reproduction.Scope: We asked a group of experts to consider the global issues associated with P-o in the terrestrial environment, methodological strengths and weaknesses, benefits to be gained from understanding the P-o cycle, and to set priorities for P-o research.Conclusions: We identified seven key opportunities for P-o research including: the need for integrated, quality controlled and functionally based methodologies; assessment of stoichiometry with other elements in organic matter; understanding the dynamics of P-o in natural and managed systems; the role of microorganisms in controlling P-o cycles; the implications of nanoparticles in the environment and the need for better modelling and communication of the research. Each priority is discussed and a statement of intent for the P-o research community is made that highlights there are key contributions to be made toward understanding biogeochemical cycles, dynamics and function of natural ecosystems and the management of agricultural systems.
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39. |
- Birks, H.H., et al.
(författare)
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The development of the aquatic ecosytem at Kråkenes Lake, western Norway, during the late glacial and early Holocene - a synthesis.
- 2000
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Ingår i: Journal of Paleolimnology. - 0921-2728 .- 1573-0417. ; 23:1, s. 91-114
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Tidskriftsartikel (refereegranskat)abstract
- This paper synthesises the palaeoecological reconstructions, including palaeoclimatic inferences, based on the available fossil record of plants (pollen, macrofossils, mosses, diatoms) and animals (chironomids, Cladocera, Coleoptera, Trichoptera, oribatid mites) in the late-glacial and early-Holocene sediments of Kråkenes Lake, western Norway, with special emphasis on changes in the aquatic ecosystem. New percentage and influx pollen diagrams for selected taxa provide insights into the terrestrial setting. The information from all the proxies is collated in a stratigraphical chart, and the inferred changes in the lake and its catchment are discussed. The individual fossil sequences are summarised by detrended correspondence analysis (DCA), and sample scores on the first DCA axes are plotted against an estimated calendar-year timescale for comparison of the timing and magnitude of changes in assemblage composition. The DCA plots show that the large late-glacial biotic changes were synchronous, and were driven by the overriding forcing factor of temperature. During the early Holocene, however, the changes in different groups were more gradual and were independent of each other, showing that other factors were important and interactive, such as the inwash of dissolved and particulate material from the catchment, the base and nutrient status of the lake-water, and the internal processes of ecosystem succession and sediment accumulation. This multi-disciplinary study, with proxies for changes in the lake and in the catchment, highlights the dependence of lake biota and processes not only on regional climatic changes but also on changes in the lake catchment and on internal processes within the lake. Rates of change for each group are also estimated and compared. The reaction times to the sharp temperature changes at the start and end of the Younger Dryas were very rapid and occurred within a decade of the temperature change. Aquatic organisms tracked the temperature and environmental changes very closely, and are probably the best recorders of late-glacial climatic change in the fossil record.
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40. |
- Steinthorsdottir, Margret, et al.
(författare)
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The Miocene : the Future of the Past
- 2021
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Ingår i: Paleoceanography and Paleoclimatology. - : American Geophysical Union (AGU). - 2572-4517 .- 2572-4525. ; 36:4
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Tidskriftsartikel (refereegranskat)abstract
- The Miocene epoch (23.03–5.33 Ma) was a time interval of global warmth, relative to today. Continental configurations and mountain topography transitioned towards modern conditions, and many flora and fauna evolved into the same taxa that exist today. Miocene climate was dynamic: long periods of early and late glaciation bracketed a ∼2 Myr greenhouse interval – the Miocene Climatic Optimum (MCO). Floras, faunas, ice sheets, precipitation, pCO2, and ocean and atmospheric circulation mostly (but not ubiquitously) covaried with these large changes in climate. With higher temperatures and moderately higher pCO2 (∼400–600 ppm), the MCO has been suggested as a particularly appropriate analogue for future climate scenarios, and for assessing the predictive accuracy of numerical climate models – the same models that are used to simulate future climate. Yet, Miocene conditions have proved difficult to reconcile with models. This implies either missing positive feedbacks in the models, a lack of knowledge of past climate forcings, or the need for re‐interpretation of proxies, which might mitigate the model‐data discrepancy. Our understanding of Miocene climatic, biogeochemical, and oceanic changes on broad spatial and temporal scales is still developing. New records documenting the physical, chemical, and biotic aspects of the Earth system are emerging, and together provide a more comprehensive understanding of this important time interval. Here we review the state‐of‐the‐art in Miocene climate, ocean circulation, biogeochemical cycling, ice sheet dynamics, and biotic adaptation research as inferred through proxy observations and modelling studies.
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41. |
- Steinthorsdottir, Margret, et al.
(författare)
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The Miocene: The Future of the Past
- 2021
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Ingår i: Paleoceanography and Paleoclimatology. - : American Geophysical Union (AGU). - 2572-4517 .- 2572-4525. ; 36:4
-
Tidskriftsartikel (refereegranskat)abstract
- The Miocene epoch (23.03–5.33 Ma) was a time interval of global warmth, relative to today. Continental configurations and mountain topography transitioned toward modern conditions, and many flora and fauna evolved into the same taxa that exist today. Miocene climate was dynamic: long periods of early and late glaciation bracketed a ∼2 Myr greenhouse interval—the Miocene Climatic Optimum (MCO). Floras, faunas, ice sheets, precipitation, pCO2, and ocean and atmospheric circulation mostly (but not ubiquitously) covaried with these large changes in climate. With higher temperatures and moderately higher pCO2 (∼400–600 ppm), the MCO has been suggested as a particularly appropriate analog for future climate scenarios, and for assessing the predictive accuracy of numerical climate models—the same models that are used to simulate future climate. Yet, Miocene conditions have proved difficult to reconcile with models. This implies either missing positive feedbacks in the models, a lack of knowledge of past climate forcings, or the need for re-interpretation of proxies, which might mitigate the model-data discrepancy. Our understanding of Miocene climatic, biogeochemical, and oceanic changes on broad spatial and temporal scales is still developing. New records documenting the physical, chemical, and biotic aspects of the Earth system are emerging, and together provide a more comprehensive understanding of this important time interval. Here, we review the state-of-the-art in Miocene climate, ocean circulation, biogeochemical cycling, ice sheet dynamics, and biotic adaptation research as inferred through proxy observations and modeling studies.
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42. |
- Hannon, G E, et al.
(författare)
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Climate change and human settlement as drivers of late-Holocene vegetational change in the Faroe Islands
- 2005
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Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 15:5, s. 639-647
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Tidskriftsartikel (refereegranskat)abstract
- Changes in Faroese land surfaces during the late Holocene reflect intimate interactions between cultural and environmental development. Analyses of fossil wood, pollen and plant macrofossils indicate that the present open landscape replaced shrubby vegetation that was present from c. 6000 BC Up to c. AD 660. Conditions altered during the late Holocene, with loss of woody vegetation and increasing erosion: trends that were initiated prior to human settlement. AMS dating of sub-fossil Betula, Salix and Juniperus found buried in peat profiles from the islands of Suouroy, Sandoy, Eysturoy, Vagar and Streymoy, revealed that the islands had at least partial woody vegetation cover up to the time of continuous settlement. The settlement horizon, identified in a lacustrine sequence on the island of Eysturoy, dated to c. AD 570. It comprised pollen evidence for the cultivation of Hordeum, cultural macrofossil assemblages, charcoal fragments, diatom assemblage changes indicating lake nutrient enrichment and physical measurements showing increased sedimentation rates. The pollen record showed that heathland development was initiated prior to anthropogenic impact. The ecosystem impacts of settlement were therefore superimposed on landscape changes that began around AD 250. The earlier changes were most likely forced by increased storminess and declining atmospheric temperatures.
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43. |
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44. |
- Aarao, J, et al.
(författare)
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Numerical implementation of the EDEM for modified Helmholtz BVPs on annular domains
- 2011
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Ingår i: JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS. - : Elsevier Science B.V., Amsterdam.. - 0377-0427. ; 235:5, s. 1342-1353
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Tidskriftsartikel (refereegranskat)abstract
- In a recent paper by the current authors a new methodology called the Extended-Domain-Eigenfunction-Method (EDEM) was proposed for solving elliptic boundary value problems on annular-like domains. In this paper we present and investigate one possible numerical algorithm to implement the EDEM. This algorithm is used to solve modified Helmholtz BVPs on annular-like domains. Two examples of annular-like domains are studied. The results and performance are compared with those of the well-known boundary element method (BEM). The high accuracy of the EDEM solutions and the superior efficiency of the EDEM over the BEM, make EDEM an excellent alternate candidate to use in the animation industry, where speed is a predominant requirement, and by the scientific community where accuracy is the paramount objective.
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45. |
- Aarao, J, et al.
(författare)
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The extended-domain-eigenfunction method for solving elliptic boundary value problems with annular domains
- 2010
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Ingår i: JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL. - : Iop. - 1751-8113 .- 1751-8121. ; 43:18, s. 185202-
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Tidskriftsartikel (refereegranskat)abstract
- Standard analytical solutions to elliptic boundary value problems on asymmetric domains are rarely, if ever, obtainable. In this paper, we propose a solution technique wherein we embed the original domain into one with simple boundaries where the classical eigenfunction solution approach can be used. The solution in the larger domain, when restricted to the original domain, is then the solution of the original boundary value problem. We call this the extended-domain-eigenfunction method. To illustrate the methods strength and scope, we apply it to Laplaces equation on an annular-like domain.
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46. |
- Alonzo, Frederic, et al.
(författare)
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Population modelling to compare chronic external radiotoxicity between individual and population endpoints in four taxonomic groups
- 2016
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 152, s. 46-59
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we modelled population responses to chronic external gamma radiation in 12 laboratory species (including aquatic and soil invertebrates, fish and terrestrial mammals). Our aim was to compare radiosensitivity between individual and population endpoints and to examine how internationally proposed benchmarks for environmental radioprotection protected species against various risks at the population level. To do so, we used population matrix models, combining life history and chronic radiotoxicity data (derived from laboratory experiments and described in the literature and the FRED ERICA database) to simulate changes in population endpoints (net reproductive rate R-0, asymptotic population growth rate lambda, equilibrium population size N-eq) for a range of dose rates. Elasticity analyses of models showed that population responses differed depending on the affected individual endpoint (juvenile or adult survival, delay in maturity or reduction in fecundity), the considered population endpoint (R-0, lambda or N-eq) and the life history of the studied species. Among population endpoints, net reproductive rate R-0 showed the lowest EDR10 (effective dose rate inducing 10% effect) in all species, with values ranging from 26 mu Gy h(-1) in the mouse Mus musculus to 38,000 mu Gy h(-1) in the fish Oryzias latipes. For several species, EDR10 for population endpoints were lower than the lowest EDR10 for individual endpoints. Various population level risks, differing in severity for the population, were investigated. Population extinction (predicted when radiation effects caused population growth rate lambda to decrease below 1, indicating that no population growth in the long term) was predicted for dose rates ranging from 2700 mu Gy h(-1) in fish to 12,000 mu Gy h(-1) in soil invertebrates. A milder risk, that population growth rate lambda will be reduced by 10% of the reduction causing extinction, was predicted for dose rates ranging from 24 mu Gy h(-1) in mammals to 1800 mu Gy h(-1) in soil invertebrates. These predictions suggested that proposed reference benchmarks from the literature for different taxonomic groups protected all simulated species against population extinction. A generic reference benchmark of 10 mu Gy h(-1) protected all simulated species against 10% of the effect causing population extinction. Finally, a risk of pseudo-extinction was predicted from 2.0 mu Gy h(-1) in mammals to 970 mu Gy h(-1) in soil invertebrates, representing a slight but statistically significant population decline, the importance of which remains to be evaluated in natural settings.
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47. |
- Bradshaw, Catherine D., et al.
(författare)
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Hydrological impact of Middle Miocene Antarctic ice-free areas coupled to deep ocean temperatures
- 2021
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Ingår i: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 14, s. 429-436
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen isotopes from ocean sediments (δ18O) used to reconstruct past continental ice volumes additionally record deep water temperatures (DWTs). Traditionally, these are assumed to be coupled (ice-volume changes cause DWT changes). However, δ18O records during peak Middle Miocene warmth (~16–15 million years ago) document large rapid fluctuations (~1–1.5‰) difficult to explain as huge Antarctic ice sheet (AIS) volume changes. Here, using climate modelling and data comparisons, we show DWTs are coupled to AIS spatial extent, not volume, because Antarctic albedo changes modify the hydrological cycle, affecting Antarctic deep water production regions. We suggest the Middle Miocene AIS had retreated substantially from previous Oligocene maxima. The residual ice sheet varied spatially more rapidly on orbital timescales than previously thought, enabling large DWT swings (up to 4 °C). When Middle Miocene warmth terminated (~13 million years ago) and a continent-scale AIS had stabilized, further ice-volume changes were predominantly in height rather than extent, with little impact on DWT. Our findings imply a shift in ocean sensitivity to ice-sheet changes occurs when AIS retreat exposes previously ice-covered land; associated feedbacks could reduce the Earth system’s ability to maintain a large AIS. This demonstrates ice-sheet changes should be characterized not only by ice volume but also by spatial extent.
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48. |
- Bradshaw-Hajek, B H, et al.
(författare)
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A composite Level Set and Extended-Domain-Eigenfunction Method for simulating 2D Stokes flow involving a free surface
- 2013
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Ingår i: Journal of Computational and Applied Mathematics. - : Elsevier. - 0377-0427 .- 1879-1778. ; 237:1, s. 389-402
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the Extended-Domain-Eigenfunction-Method (EDEM) is combined with the Level Set Method in a composite numerical scheme for simulating a moving boundary problem. The liquid velocity is obtained by formulating the problem in terms of the EDEM methodology and solved using a least square approach. The propagation of the free surface is effected by a narrow band Level Set Method. The two methods both pass information to each other via a bridging process, which allows the position of the interface to be updated. The numerical scheme is applied to a series of problems involving a gas bubble submerged in a viscous liquid moving subject to both an externally generated flow and the influence of surface tension.
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49. |
- Bradshaw-Hajek, B. H., et al.
(författare)
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Dynamic Dielectric Response of Concentrated Colloidal Dispersions: Comparison between Theory and Experiment
- 2009
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Ingår i: Langmuir. - : ACS American Chemical Society. - 0743-7463 .- 1520-5827. ; 25:4, s. 1961-1969
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Tidskriftsartikel (refereegranskat)abstract
- The cell-model electrokinetic theory of Ahualli et al. Langmuir 2006, 22, 704 1; Ahualli et al. J. Colloid Interface Sci. 2007, 309, 342; and Bradshaw-Hajek et al. Langmuir 2008, 24, 4512 is applied to a dense suspension of charged spherical particles, to exhibit the systems dielectric response to an applied electric field as a function of solids volume fraction. The models predictions of effective permittivity and complex conductivity are favorably compared with published theoretical calculations and experimental measurements on dense colloidal systems. Physical factors governing the volume fraction dependence of the dielectric response are discussed.
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50. |
- Bradshaw-Hajek, B.H., et al.
(författare)
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Frequency-dependent electrical conductivity of concentrated dispersions of spherical colloidal particles
- 2008
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 24:9, s. 4512-4522
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Tidskriftsartikel (refereegranskat)abstract
- This paper outlines the application of a self-consistent cell-model theory of electrokinetics to the problem of determining the electrical conductivity of a dense suspension of spherical colloidal particles. Numerical solutions of the standard electrokinetic equations, subject to self-consistent boundary conditions, are implemented in formulas for the electrical conductivity appropriate to the particle-averaged cell model of the suspension. Results of calculations as a function of frequency, zeta potential, volume fraction, and electrolyte composition, are presented and discussed. © 2008 American Chemical Society.
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