| 3971. |
- Hallquist, Åsa Marita, et al.
(författare)
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On-board Measurements of Nanoparticles from a SCR-Equipped Marine Diesel Engine
- 2013
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Ingår i: Environmental Science & Technology. - : American Chemical Society. - 0013-936X .- 1520-5851. ; 47:2
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Tidskriftsartikel (refereegranskat)abstract
- In this study nanoparticle emissions have been characterised on-board a ship with focus on number, size and volatility. Measurements were conducted on one of the ship’s four main 12 600 kW medium–speed diesel engines which use low sulphur marine residual fuel and have a Selective Catalytic Reduction (SCR) system for NOX abatement. The particles were measured after the SCR with an engine exhaust particle sizer spectrometer (EEPS), giving particle number and mass distributions in the size range of 5.6-560 nm. The thermal characteristics of the particles were analysed using a volatility tandem DMA system (VTDMA). A dilution ratio of 450-520 was used which is similar to the initial real-world dilution. At a stable engine load of 75% of the maximum rated power, and after dilution and cooling of the exhaust gas, there was a bimodal number size distribution, with a major peak at ~10 nm and a smaller peak at around 30-40 nm. The mass distribution peaked around 20 nm and at 50-60 nm. The emission factor for particle number, EFPN, for an engine load of 75% in the open-sea was found to be 10.4 ± 1.6 × 1016 (kg fuel)-1 and about 50% of the particles by number were found to have a non-volatile core at 250 °C. Additionally, 20 nm particles consist of ~40% of non-volatile material by volume (evaporative temperature 250 °C) while the particles with a particle diameter <10 nm evaporate completely at a temperature of 130-150 °C. Emission factors for NOX, CO and CO2 for an engine load of 75% in the open-sea were determined to 4.06 ± 0.3 g (kg fuel)-1, 2.15 ± 0.06 g (kg fuel)-1 and 3.23 ± 0.08 kg (kg fuel)-1, respectively. This work contributes to an improved understanding of particle emissions from shipping using modern pollution reduction measures such as SCR and fuel with low sulphur content.
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| 3972. |
- Hamberg, Mattias, et al.
(författare)
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Board participation, toeholds and the cross-border effect
- 2013
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Ingår i: International Business Review. - : Elsevier BV. - 0969-5931 .- 1873-6149. ; 22:5
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Tidskriftsartikel (refereegranskat)abstract
- Research shows that the bid announcement return (BAR) of the acquiring firm is lower for cross-border than domestic acquisition announcements. The current lack of economically based explanations for this effect, labeled the cross-border effect by Moeller and Schlingemann (2005), motivates our study. We use unique hand-collected corporate governance data to study how the relationships between acquiring and target firms prior to a bid announcement affect the cross-border effect. Our tests show that non-operating associations between the acquiring and target firms, in the form of board participation and toeholds, have a positive effect on the BAR. The cross-border effect disappears when we control for board participation and toeholds. Thus, we suggest that the cross-border effect is at least partly a consequence of information asymmetries and the adverse selection problem that they generate.
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| 3973. |
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| 3974. |
- Hamilton, Kerstin, 1978, et al.
(författare)
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The Hambantota Connection: Constructing landscapes, contesting modernity
- 2014
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- As China re-emerges as a superpower and Western hegemony wanes, the Indian Ocean has become a geopolitical nexus. In the centre of this new map lies Hambantota, a fishing village on the south coast of Sri Lanka. Here, Chinese capital and labour has been ploughed into the construction of an international airport, a cricket stadium, and what is expected to become the largest port in South Asia. Hambantota seems to fit perfectly into what American and Indian military strategists refer to as the "String of Pearls": a plot of vital infrastructure developments, scattered along the rim of the Indian Ocean. The West no longer represents the only model of development, and there are now alternative versions of modernity that compete with each other. Hambantota can be understood as a microcosm that contains this contested modernity. Drawing upon documentary photography, development geography and economic anthropology, the authors trace connections between local phenomena and global patterns. The Hambantota Connection presents a visual sociology of logistics and livelihoods, of authoritarian leadership and anthropocenic landscapes, and of economic fictions and planetary fluxes. It explores what a place can say about the world, and how the world can be grasped through abstraction and speculation.
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| 3975. |
- Hamis, S., et al.
(författare)
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Spatial cumulant models enable spatially informed treatment strategies and analysis of local interactions in cancer systems
- 2023
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Ingår i: Journal of Mathematical Biology. - : Springer Nature. - 0303-6812 .- 1432-1416. ; 86:5
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Tidskriftsartikel (refereegranskat)abstract
- Theoretical and applied cancer studies that use individual-based models (IBMs) have been limited by the lack of a mathematical formulation that enables rigorous analysis of these models. However, spatial cumulant models (SCMs), which have arisen from theoretical ecology, describe population dynamics generated by a specific family of IBMs, namely spatio-temporal point processes (STPPs). SCMs are spatially resolved population models formulated by a system of differential equations that approximate the dynamics of two STPP-generated summary statistics: first-order spatial cumulants (densities), and second-order spatial cumulants (spatial covariances). We exemplify how SCMs can be used in mathematical oncology by modelling theoretical cancer cell populations comprising interacting growth factor-producing and non-producing cells. To formulate model equations, we use computational tools that enable the generation of STPPs, SCMs and mean-field population models (MFPMs) from user-defined model descriptions (Cornell et al. Nat Commun 10:4716, 2019). To calculate and compare STPP, SCM and MFPM-generated summary statistics, we develop an application-agnostic computational pipeline. Our results demonstrate that SCMs can capture STPP-generated population density dynamics, even when MFPMs fail to do so. From both MFPM and SCM equations, we derive treatment-induced death rates required to achieve non-growing cell populations. When testing these treatment strategies in STPP-generated cell populations, our results demonstrate that SCM-informed strategies outperform MFPM-informed strategies in terms of inhibiting population growths. We thus demonstrate that SCMs provide a new framework in which to study cell-cell interactions, and can be used to describe and perturb STPP-generated cell population dynamics. We, therefore, argue that SCMs can be used to increase IBMs' applicability in cancer research.
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| 3976. |
- Hamlet, Oskar, 1981
(författare)
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Index Classes for Vector Fields and Their Relation to Certain Characteristic Classes
- 2013
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Ingår i: Mathematica Scandinavica. - : Det Kgl. Bibliotek/Royal Danish Library. - 1903-1807 .- 0025-5521. ; 112:2, s. 216-224
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Tidskriftsartikel (refereegranskat)abstract
- While studying vector fields on manifolds with boundary there are three important indexes to consider. We construct three cohomology classes to compute these. We relate these classes to other classes, the relative Euler class as defined by Sharafutdinov and the secondary Chern-Euler class as defined by Sha. Our results also yield a new proof of the Poincare-Hopf index theorem.
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| 3977. |
- Hamlet, Oskar, 1981
(författare)
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Tight Holomorphic Maps, a Classification
- 2013
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Ingår i: Journal of Lie Theory. - 0949-5932. ; 23:3, s. 639-654
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Tidskriftsartikel (refereegranskat)abstract
- Tight maps was introduced along tight homomorphisms by Burger, Iozzi and Wienhard with aims towards maximal representations. In this paper we classify all tight holomorphic maps between Hermitian symmetric spaces.
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| 3978. |
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| 3979. |
- Hamlet, Oskar, 1981
(författare)
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Tight maps, a classification
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis concerns the classification of tight totally geodesic maps between Hermitian symmetric spaces of noncompact type. In Paper I we classify holomorphic tight maps. We introduce a new criterion for tightness of Hermitian regular subalgebras. Following the classification of holomorphic maps by Ihara and Satake we go through the lists of (H2)-homomorphisms and Hermitian regular subalgebras and determine which are tight. In Paper II we show that there are no nonholomorphic tight maps into classical codomains (except the known ones from the Poincar\'e disc). As the proof relies heavily on composition arguments we investigate in detail when a composition of tight maps is tight. We develop a new criterion for nontightness in terms of how complex representations of Hermitian Lie algebras branches when restricted to certain subalgebras. Using this we prove the result for a few low rank cases which then extends to the full result by composition arguments. The branching method in Paper II fails to encompass exceptional codomains. We treat one exceptional case using weighted Dynkin diagrams and the other by showing that there exists an unexpected decomposition of homomorphisms in Paper III. Together these three papers yield a full classification of tight maps from irreducible domains.
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| 3980. |
- Hamlet, Oskar, 1981
(författare)
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TIght maps and holomorphicity
- 2014
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Ingår i: Transformation groups. - : Springer Science and Business Media LLC. - 1083-4362 .- 1531-586X. ; 19:4, s. 999-1026
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Tidskriftsartikel (refereegranskat)abstract
- Tight maps were introduced and studied along tight homomorphisms by Burger, Iozzi and Wienhard with aims towards maximal representations. In this paper we show that, with the exception of maps from the Poincaré disc, tight maps into classical Hermitian symmetric spaces must be holomorphic or antiholomorphic. Together with previous results this completely classi_es tight maps into classical codomains.
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