| 1. |
- Ahlborg, Helene, 1980, et al.
(författare)
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Provision of electricity to African households : The importance of democracy and institutional quality
- 2015
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 87, s. 125-135
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Tidskriftsartikel (refereegranskat)abstract
- How can differences in per capita household electricity consumption across African countries be understood? Based on theories that highlight the importance of democracy and institutional quality for provision of public goods, the aim of the paper is to analyse the degree to which the level of per capita household electricity consumption in African countries can be attributed to the countries’ democratic status and their institutional quality. We rely on regression analysis employing a pooled data set for 44 African countries over the time period 1996–2009. The analysis shows that democracy and institutional quality both have significant positive effects on per capita household consumption of electricity. Our results have implications for how energy sector reforms are promoted in developing countries. At a more general level they illustrate that institution-building policy efforts are relevant also in areas where contemporary debates have tended to primarily centre on economic development, financial prerequisites and ownership issues.
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| 2. |
- Alrifaiy, Ahmed, et al.
(författare)
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A lab-on-a-chip for hypoxic patch clamp measurements combined with optical tweezers and spectroscopy : first investigations of single biological cells
- 2015
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Ingår i: Biomedical engineering online. - : Springer Science and Business Media LLC. - 1475-925X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- The response and the reaction of the brain system to hypoxia is a vital research subject that requires special instrumentation. With this research subject in focus, a new multifunctional lab-on-a-chip (LOC) system with control over the oxygen content for studies on biological cells was developed. The chip was designed to incorporate the patch clamp technique, optical tweezers and absorption spectroscopy. The performance of the LOC was tested by a series of experiments. The oxygen content within the channels of the LOC was monitored by an oxygen sensor and verified by simultaneously studying the oxygenation state of chicken red blood cells (RBCs) with absorption spectra. The chicken RBCs were manipulated optically and steered in three dimensions towards a patch-clamp micropipette in a closed microfluidic channel. The oxygen level within the channels could be changed from a normoxic value of 18% O 2 to an anoxic value of 0.0-0.5% O 2. A time series of 3 experiments were performed, showing that the spectral transfer from the oxygenated to the deoxygenated state occurred after about 227 ± 1 s and a fully developed deoxygenated spectrum was observed after 298 ± 1 s, a mean value of 3 experiments. The tightness of the chamber to oxygen diffusion was verified by stopping the flow into the channel system while continuously recording absorption spectra showing an unchanged deoxygenated state during 5400 ± 2 s. A transfer of the oxygenated absorption spectra was achieved after 426 ± 1 s when exposing the cell to normoxic buffer. This showed the long time viability of the investigated cells. Successful patching and sealing were established on a trapped RBC and the whole-cell access (Ra) and membrane (Rm) resistances were measured to be 5.033 ± 0.412 M Ω and 889.7 ± 1.74 M Ω respectively.
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| 3. |
- Andersen, M. S., et al.
(författare)
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To facilitate a fair bioeconomy transition, stronger regional-level linkages are needed
- 2022
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Ingår i: Biofuels Bioproducts & Biorefining-Biofpr. - : Wiley. - 1932-104X .- 1932-1031. ; 16:4, s. 929-941
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Tidskriftsartikel (refereegranskat)abstract
- The great hopes in Brussels that a circular bioeconomy will help bridge the growing divide between urban and rural areas and allow the hinterlands to prosper from 'green growth' are addressed in this article, which reflects on insights from three Nordic case studies of brown, green and blue biomass use at different levels of technology readiness. A closer examination of the forward, backward, fiscal and final demand linkages at regional level from increased biomass utilization, from eastern Finland and northern Sweden to Jutland and North Atlantic islands, suggests that linkages are and will remain relatively weak, predominantly dashing the expectations. As suppliers and exporters of natural resources, disadvantaged regions may all too easily get locked into a 'staples trap', where the value creation evaporates owing in part to the steep start-up costs and the associated boom-and-bust cycles, which place them in a weak position vis-a-vis the resource manufacturers and consumers. To make the prospects of development, employment and prosperity in the hinterlands materialize, measures are needed to strengthen the regional-level economic linkages. Regional-level revolving funds based on benefit-sharing instruments related to natural resources can be used to bolster economic development, as reflected in such schemes present in both China and Canada. We call for further research into whether and how such approaches can be replicated successfully by channeling revenues from biomass cultivation to regional-scale revolving funds, with mandates to strengthen long-term economic linkages and prosperity within the hinterlands. (c) 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd
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| 4. |
- Busch, Michael, 1983, et al.
(författare)
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Validation of binuclear descriptor for mixed transition metal oxide supported electrocatalytic water oxidation
- 2013
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Ingår i: Catalysis Today. - : Elsevier BV. - 0920-5861 .- 1873-4308. ; 202:1, s. 114-119
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Tidskriftsartikel (refereegranskat)abstract
- The energy profiles of the di-hydroxo – di-oxo – peroxo pathway are discussed for a set of 3d transition metal oxides comprising V(III–V), Cr(III–V), Mn(II–IV, Mn(III–V), Fe(II–IV), Co(II–IV) and Ni(II–IV) using density functional theory (DFT). Two classes of oxides were identified. The first class, comprising V(III–V), Cr(III–V) and Fe(II–IV), displays exothermicity for the oxidation of di-hydroxo to di-oxo versus the tyrosine/tyrosyl-radical (TyrOH/TyrO) couple and endothermicity for the subsequent O-O bond formation ([−/+] class), while the second class, comprising Mn(III–V), Co(II–IV) and Ni(II–IV), shows endothermicity with respect to the oxidation step and exothermicity for the O-O bond formation ([+/−] class). The energetics of the endothermicity (exothermicity) for the oxidation step is reflected in the exothermicity (endothermicity) of the subsequent O-O bond formation step. Mn(II–IV) is not part of any of the two classes. Instead it shows zero exothermicity with respect to TyrOH/TyrO for the oxidation step and a small endothermicity for the O-O bond formation step. Despite the promising energy profile Mn(II–IV) is argued to be inactive due to a large activation barrier. A set of improved hetero-nuclear candidate catalysts is predicted by mixing [−/+] with [+/−] transition metal oxides. A simple and efficient method to estimate the energy profile of mixed transition metal oxides from the homo-nuclear systems is demonstrated. The validity of this procedure is checked and agreement with the explicitly calculated values is found. All considered heteronuclear candidate catalysts display enhanced performance compared to the pure homonuclear systems.
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| 5. |
- Busch, Michael, 1983, et al.
(författare)
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Water Oxidation on MnOx and IrOx: Why Similar Performance?
- 2013
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:1, s. 288-292
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Tidskriftsartikel (refereegranskat)abstract
- The critical steps in water oxidation at a binuclear Mn(II–IV) oxide site are revisited. Ideal stabilities of intermediates are confirmed by comparing to results for a binuclear Ir(III–V) system. The latter in turn is known to be an excellent water oxidation catalyst. The inefficiency of the binuclear Mn(II–IV) site is owing to the high activation energy for the chemical step whereby MnIV═O double bonds on adjacent sites are broken prior to forming the MnIII—O—O—MnIII peroxy moiety. A rationale for Mn(II–IV)—Mn(III–V) mixed oxidation state for water oxidation catalysis, analogous to mixed transition metal oxide systems, is offered. Possible virtues of the kinetic stability of the binuclear MnIV═O moiety are discussed, utilizing its oxidizing power by sidestepping oxygen evolution.
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| 6. |
- Carlsson, Bo, et al.
(författare)
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The evolving domain of entrepreneurship research
- 2013
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Ingår i: Small Business Economics. - : Springer Science and Business Media LLC. - 0921-898X .- 1573-0913. ; 41:4, s. 913-930
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Tidskriftsartikel (refereegranskat)abstract
- Research on entrepreneurship has flourished in recent years and is evolving rapidly. This article explores the history of entrepreneurship research, how the research domain has evolved, and its current status as an academic field. The need to concretize these issues stems partly from a general interest in defining the current research domain and partly from the more specific tasks confronting the prize committee of the Global Award for Entrepreneurship Research. Entrepreneurship has developed in many sub-fields within several disciplines-primarily economics, management/business administration, sociology, psychology, economic and cultural anthropology, business history, strategy, marketing, finance, and geography-representing a variety of research traditions, perspectives, and methods. We present an analytical framework that organizes our thinking about the domain of entrepreneurship research by specifying elements, levels of analysis, and the process/context. An overview is provided of where the field stands today and how it is positioned relative to the existing disciplines and new research fields upon which it draws. Areas needed for future progress are highlighted, particularly the need for a rigorous dynamic theory of entrepreneurship that relates entrepreneurial activity to economic growth and human welfare. Moreover, applied work based on more careful design as well as on theoretical models yielding more credible and robust estimates seems also highly warranted.
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| 7. |
- Coria, Jessica, 1979, et al.
(författare)
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The progress of GHG markets : opportunities and risks
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The climate negotiations at the COP15 in December 2009 did not produce a new international treaty with binding emissions commitments but the Copenhagen Accord for dealing with post-2012 climate change. Given the current climate negotiation process it is unlikely that we will see a global climate agreement soon on a global cap between all Convention members participating in a single carbon market. We may be more likely to see a stepwise process moving towards this scenario, most likely involving linkages between different national policy programs when it comes to mitigation as well as offsetting emissions. In such a process countries will offer commitments based on their domestic abilities, preferences and policies, norms and institutions. National and sub-national policies are thus likely to be the de-facto building blocks of nations' abilities to make and fulfill international commitments. However, also with multilateral mitigation programs without binding commitments, carbon markets will be needed as well as international authorities that support measurement, reporting and verification rules and the international registries. Such markets will necessarily be complicated and temporary in a world without an overarching binding agreement. There will be numerous tradeoffs between different kinds of second-best arrangements. The purpose of this report is to build knowledge about the effects of the development of regional and international carbon markets and the auxiliary technology agreements that might be needed. Among the topics we address are: the evolution and integration of carbon markets, the impacts of policy and technology cost uncertainty on the cost of meeting targets through a carbon market mechanism, the effect of banking, price floors and ceilings, institutional constraints and technological change in the further development of carbon markets and their links to other environmental policy instruments, and the potential of REDD-plus to encourage sustainable forest development and climate mitigation.
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| 8. |
- Eidevåg, Tobias, 1987, et al.
(författare)
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Angle of repose of snow: An experimental study on cohesive properties
- 2022
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Ingår i: Cold Regions Science and Technology. - : Elsevier BV. - 0165-232X .- 1872-7441. ; 194
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Tidskriftsartikel (refereegranskat)abstract
- The angle of repose is a measure reflecting the internal friction and cohesion properties of a granular material. In this paper, we present an experimental setup and measurements for the angle of repose of snow for seven different snow samples over a large range of temperatures. The results show that the angle of repose is dependent on the fall height, the temperature, and the grain size of the snow. These variables are quantified, and their interdependencies are separately studied. With increased snow temperature, the angle of repose increases, and this can be explained by the presence of a liquid layer on ice that can be thermodynamically stable at temperatures below the melting point of water. With decreasing grain size the angle of repose also increases which is expected since the cohesive energy decreases more slowly than the grain mass. For increasing fall height, the snow grains generally accelerate to larger collisional velocities, yielding a smaller angle of repose. In general, the dimensionless cohesion number was found to largely reflect the dependencies of the variables and is therefore useful for understanding what affects the angle of repose. The results demonstrate that the drag force and collision dynamics of ice grains are important for understanding how snow accumulates on a surface, for example if one desires predicting snow accretion by simulating a dispersed cloud of snow. © 2021
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| 9. |
- Eidevåg, Tobias, 1987, et al.
(författare)
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Collisional damping of spherical ice particles
- 2021
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910 .- 1873-328X. ; 383, s. 318-327
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents experimental values for the coefficient of restitution (e(n)) for millimeter-sized ice particles colliding with massive walls at different temperatures. Three different wall materials are tested: hardened glass, ice and Acrylonitrile butadiene styrene (ABS) polymer. The results show a high sensitivity to impact velocity V-i, where e(n) decreases rapidly with increasing V-i. The results also show a decrease in e(n) with increasing temperature T. A novel model that predicts e(n) based on the assumption of collisional melting and viscous damping caused by an increased premelted liquid-layer, is proposed. The model predicts both the velocity and the temperature trends seen in the experiments. The difference obtained in experiments between wall materials is also captured by the new model. A generalized regime map for ice particle collisions is proposed to combine the new model with previous work. (C) 2021 The Author(s).
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| 10. |
- Enger, Jonas, 1966, et al.
(författare)
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Optical tweezers applied to a microfluidic system
- 2004
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 4, s. 196-200
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Tidskriftsartikel (refereegranskat)abstract
- We will demonstrate how optical tweezers can be combined with a microfluidic system to create a versatile microlaboratory. Cells are moved between reservoirs filled with different media by means of optical tweezers. We show that the cells, on a timescale of a few seconds, can be moved from one reservoir to another without the media being dragged along with them. The system is demonstrated with an experiment where we expose E. coli bacteria to different fluorescent markers. We will also discuss how the system can be used as an advanced cell sorter. It can favorably be used to sort out a small fraction of cells from a large population, in particular when advanced microscopic techniques are required to distinguish various cells. Patterns of channels and reservoirs were generated in a computer and transferred to a mask using either a sophisticated electron beam technique or a standard laser printer. Lithographic methods were applied to create microchannels in rubber silicon (PDMS). Media were transported in the channels using electroosmotic flow. The optical system consisted of a combined confocal and epi-fluorescence microscope, dual optical tweezers and a laser scalpel.
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