| 1. |
- Andersson, Sara-Linnea, et al.
(author)
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Plug-in Hybrid Electric Vehicles as Regulating Power Providers - Case Studies of Sweden and Germany
- 2010
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In: Energy Policy. - : Elsevier BV. - 0301-4215. ; 38:6, s. 2751-2762
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Journal article (peer-reviewed)abstract
- This study investigates plug-in hybrid electric vehicles (PHEVs) as providers of regulating power in the form of primary, secondary and tertiary frequency control. Previous studies have shown that PHEVs could generate substantial profits while providing ancillary services. This study investigates under what conditions PHEVs can generate revenues using actual market data, i.e. prices and activations of regulating power, from Sweden and Germany from four months in 2008. PHEV market participation is modelled for individual vehicles in a fleet subject to a simulated movement pattern. Costs for infrastructure and vehicle-to-grid equipment are not included in the analysis. The simulation results indicate that maximum average profits generated on the German markets are in the range 30–80 h per vehicle and month whereas the Swedish regulating power markets give no profit.In addition, an analysis is performed to identify strengths, weaknesses, opportunities, and threats (SWOT) of PHEVs as regulating power providers. Based on the simulation results and the SWOT analysis, characteristics for an ideal regulating power market for PHEVs are presented.
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| 2. |
- Akhtar, Farid, et al.
(author)
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Colloidal processing and CO2 capture performance of sacrificially templated zeolite monoliths
- 2012
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In: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 97, s. 289-296
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Journal article (other academic/artistic)abstract
- Sacrificial templating of suspension cast and subsequently thermally treated zeolite monoliths with glassy carbon spheres and fibers yielded zeolite 13X and silicalite-1 monoliths with macroporosities up to 50 vol%. Homogeneous distribution of the macroporosity in hierarchically porous monoliths was obtained by tailoring the surface chemistry of the carbon particles by polyelectrolyte-assisted adsorption of zeolite particles. The effect of amount of kaolin binder and temperature for the thermal treatment on the monoliths strength, surface area and CO2 uptake was studied by diametral compression tests, electron microscopy, X-ray diffraction and gas adsorption. Cyclic adsorption and regeneration measurements showed that zeolite 13X monoliths display a high CO2 uptake while the silicalite-1 monoliths could be regenerated with a relatively low energy penalty.
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| 3. |
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| 4. |
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| 5. |
- Akhtar, Farid, et al.
(author)
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Structuring adsorbents and catalysts by processing of porous powders
- 2014
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In: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 34:7, s. 1643-1666
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Journal article (peer-reviewed)abstract
- Microporous materials such as zeolites, metal organic frameworks, activated carbons and aluminum phosphates are suitable for catalysis and separation applications. These high surface area materials are invariably produced in particulate forms and need to be transformed into hierarchically porous structures for high performance adsorbents or catalysts. Structuring of porous powders enables an optimized structure with high mass transfer, low pressure drop, good heat management, and high mechanical and chemical stability. The requirements and important properties of hierarchically porous structures are reviewed with a focus on applications in gas separation and catalysis. Versatile powder processing routes to process porous powders into hierarchically porous structures like extrusion, coatings of scaffolds and honeycombs, colloidal processing and direct casting, and sacrificial approaches are presented and discussed. The use and limitations of the use of inorganic binders for increasing the mechanical strength is reviewed, and the most important binder systems, e.g. clays and silica, are described in detail. Recent advances to produce binder-free and complex shaped hierarchically porous monoliths are described and their performance is compared with traditional binder-containing structured adsorbents. Needs related to better thermal management and improved kinetics and volume efficiency are discussed and an outlook on future research is also given.
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| 6. |
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| 7. |
- Andersson, Linnéa, et al.
(author)
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Colloidal processing and CO2-capture performance of hierarchically porous Al2O3-zeolite 13X composites
- 2012
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In: Journal of Ceramic Science and Technology. - 2190-9385. ; 3:1, s. 9-16
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Journal article (peer-reviewed)abstract
- Hierarchically porous composites for CO2-capture have been produced by coating the inner walls of foam-like macroporous alumina monoliths, produced by templated synthesis, with microporous zeolite 13X particles. Homogeneous and dense coatings of the particulate adsorbent were obtained when the impregnation process was performed at a pH above 9. At this pH-level the colloidally stable suspensions of the negatively charged zeolite 13X particles could fill all the voids of the highly connected pore space of the alumina supports and attach to the monolith walls, which had been pre-coated with poly(ethylene imine). A CO2-uptake as high as 5 mmol CO2/g zeolite 13X was achieved for alumina-zeolite 13X composites through minimisation of the added inorganic binder, kaolin, to only 3.0 wt% with respect to zeolite content, and through optimisation of the thermal treatment.
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| 8. |
- Andersson, Linnéa, et al.
(author)
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Evaluating pore space in macroporous ceramics with water-based porosimetry
- 2013
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In: Journal of The American Ceramic Society. - : Wiley. - 0002-7820 .- 1551-2916. ; 96:6, s. 1916-1922
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Journal article (peer-reviewed)abstract
- We show that water-based porosimetry (WBP), a facile, simple, and nondestructive porosimetry technique, accurately evaluates both the pore size distribution and throat size distribution of sacrificially templated macroporous alumina. The pore size distribution and throat size distribution derived from the WBP evaluation in uptake (imbibition) and release (drainage) mode, respectively, were corroborated by mercury porosimetry and X-ray micro-computed tomography (μ-CT). In contrast with mercury porosimetry, the WBP also provided information on the presence of “dead-end pores” in the macroporous alumina.
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| 9. |
- Andersson, Linnea, et al.
(author)
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Flash visual evoked potentials are unreliable as markers of ICP due to high variability in normal subjects.
- 2012
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In: Acta neurochirurgica. - : Springer Science and Business Media LLC. - 0942-0940 .- 0001-6268. ; 154:1, s. 121-127
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Journal article (peer-reviewed)abstract
- BACKGROUND: Previous publications have suggested a high correlation between flash visual evoked potential (F-VEP) N2 peak latency and intracranial pressure. This would enable F-VEP to be used as a non-invasive and inexpensive method to estimate ICP in a number of settings. However, basic knowledge about variability across subjects and test-retest properties of the F-VEP is lacking. METHODS: Fifteen healthy adult subjects were tested on three different occasions. F-VEP responses were recorded using international standards. FINDINGS: For the tested population, mean N2 latency was 65.7ms (SD 10.7ms) and the range was 48-110ms. Intra-individual variability was high, in four of the 15 subjects more than 15ms between testing sessions. The same was found for P2 latency and for N2 and P2 amplitudes. The response waveform was very variable and unambiguous marking of peaks was often diffucult. One out of the 15 subjects had a very poorly developed F-VEP response, but a normal pattern-reversal VEP response. CONCLUSIONS: F-VEP has a wide range of latency, amplitude and waveform across normal subjects. A large proportion of subjects also had a high intra-individual variability over time. This variability makes F-VEPs unreliable as a marker for intracranial pressure, and caution in interpreting F-VEP changes in clinical work is advised.
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| 10. |
- Andersson, Linnéa, et al.
(author)
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Permeability, pore connectivity and critical pore throat control of expandable polymeric sphere templated macroporous alumina
- 2011
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In: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 59:3, s. 1239-1248
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Journal article (peer-reviewed)abstract
- We have regulated the permeability in macroporous alumina materials by manipulating the connectivity of the pore phase and the sizes of the smallest constrictions between connected pores. Templating with particle-coated expandable polymeric spheres (EPS) significantly increased the fraction of isolated pore clusters, and reduced both the sizes and the number of connections with neighboring pores, as determined by three-dimensional evaluation with X-ray micro-computed tomography. The stable particle coating, applied onto the EPS surfaces using polyelectrolyte multilayers, reduced the volume expansion and the coalescence of the EPS at elevated temperatures, which reduced the simulated permeability by as much as two orders of magnitude compared to templating with uncoated EPS in materials of similar porosities. We show that the Katz-Thompson model accurately predicts the permeability for the macroporous alumina materials with porosities of 46-76%. This suggests that the permeability to fluid flow in these materials is governed by the smallest constrictions between connected pores: the critical pore throat diameter.
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