3,767 research outputs found
The neglected importance of corporate perceptions and positions for the long-term development of CCS
Many companies that produce fossil fuels or fossil fuel-derived products show a strong belief in a large and continuing role for fossil fuels in the global economy up to 2050 and beyond. These companies are generally expected to be amongst the primary consumers of carbon capture and storage (CCS) technology. So far, however, fossil fuel companies have shown only moderate interest in CCS. Whilst a lot of potential operational barriers to CCS adoption have been identified in the literature, the value of CCS from a corporate strategy perspective has sometimes been assumed, but rarely explored. This paper asks the following question: What are the perceptions and positions of fossil fuel companies on CCS and how does this inform their decision-making on CCS investment and advocacy? This paper addresses this issue by presenting the results of in-depth interviews with high-level CCS experts from major multinational oil and gas companies and major coal mining firms. The results indicate that CCS would require a significant change within the business strategy of fossil fuel companies. This is contrary to the common argument that CCS is attractive because the technology is regarded as not being very disruptive to the incumbent energy system as it leaves most of the existing infrastructure, actor constellations and institutions intact. While fossil fuel companies engage in CCS development, it is often to familiarise themselves with technologies that might have future value if markets for these technologies take off. In several cases, CCS engagement has served the strategic need to weaken the link between fossil fuel extraction and climate change, build up shareholder trust, and improve public perception. However, there is little evidence that these companies engage in CCS to develop a strategic insurance against climate policy risks to their core businesses
The socio-technical dynamics of chemical feedstock transitions : the case of renewable raw materials in the UK
Much public and private effort is being directed towards the development of more sustainable
chemical feedstocks, yet the associated complexities of technological transitions and the
technical, institutional and policy-related challenges they raise are often not wholly
recognised. This thesis aims to develop an understanding of the key dynamics of
technological change in the chemical industry, with respect to changes in feedstocks and the
influence of the changing energy (and climate policy) landscape. It builds on, and contributes
to, the ‘innovations’ literature that seeks to translate empirical research on past technological
transitions into practical guidance for policy-makers. In particular, this thesis explores the
relevance of the close relationship – or ‘co-evolution’ – between chemicals and liquid fuels
production, which has not been analysed elsewhere.
Transitions between technological systems involve evolutionary processes. The past both
shapes the current system and influences future options and pathways. This thesis
investigates the historical transition from coal-based to petrochemical feedstocks in the UK
(1921-1967), applying a system dynamics approach to extract and elucidate the key
interrelationships between technologies, policy and society. The findings are then used to
inform a series of interviews with key organisations to gain insights into expectations for
renewable raw materials (RRM) in the UK. The results provide a strong indication of the
decision-making procedures of actors, and tensions between different industrial activities.
They thus provide an empirical basis for developing foresight scenarios that might help
inform the current debate about technological transitions, especially those to RRM.
This thesis shows that the technological trajectory of the organic chemical industry has for
many decades been influenced heavily by governmental attempts to steer technological
change towards a changing set of policy priorities. This process has been accompanied by
attempts of industrialists to steer policy priorities towards preferred technological trajectories.
Parallels can be drawn with the current attempts of policymakers to achieve greater societal
sustainability. Results indicate that the innovation system around RRM is already
experiencing the socio-technical dynamics of regime disruption and competing designs
Using blubber explants to investigate adipose function in grey seals:glycolytic, lipolytic and gene expression responses to glucose and hydrocortisone
Adipose tissue is fundamental to energy balance, which underpins fitness and survival. Knowledge of adipose regulation in animals that undergo rapid fat deposition and mobilisation aids understanding of their energetic responses to rapid environmental change. Tissue explants can be used to investigate adipose regulation in wildlife species with large fat reserves, when opportunities for organismal experimental work are limited. We investigated glucose removal, lactate, glycerol and NEFA accumulation in media, and metabolic gene expression in blubber explants from wild grey seals. Glycolysis was higher in explants incubated in 25 mM glucose (HG) for 24 h compared to controls (C: 5.5 mM glucose). Adipose-derived lactate likely contributes to high endogenous glucose production in seals. Lipolysis was not stimulated by HG or high hydrocortisone (HC: 500 nM hydrocortisone) and was lower in heavier animals. HC caused NEFA accumulation in media to decrease by ~30% relative to C in females, indicative of increased lipogenesis. Lipolysis was higher in males than females in C and HG conditions. Lower relative abundance of 11-β-hydroxysteroid dehydrogenase 1 mRNA in HG explants suggests glucose involvement in blubber cortisol sensitivity. Our findings can help predict energy balance responses to stress and nutritional state in seals, and highlight the use of explants to study fat tissue function in wildlife
Differences in performance and kinematics when catching under block versus random temporal constraints
Postural adjustments in catching: on the interplay between segment stabilization and equilibrium control
The purpose of this study was to investigate postural adjustments in one-handed ball catching. Specifically, the functional role of anticipatory postural adjustments (APA) during the initial arm raising and subsequent postural adjustments (SPA) for equilibrium control and ball-hand impact were scrutinized. Full-body kinematics and kinetics allowed an analysis of the mechanical consequences of raising up the arm and preparing for ball-hand impact. APA for catching were suggested to be for segment stabilization. SPA had a functional role for equilibrium control by an inverted pendulum mechanism but were also involved in preparing for the impact of the ball on the hand, which was illustrated by an increased postural response at the end of the movement. These results were compared with raising up the arm in a well-studied reaction-time task, for which an additional counter rotation equilibrium mechanism was observed. Together, our findings demonstrate that postural adjustments should be investigated in relation to their specific functional task constraints, rather than generalizing the functional role of these postural adjustments over different tasks
Building multiparticle states with teleportation
We describe a protocol which can be used to generate any N-partite pure
quantum state using Einstein-Podolsky-Rosen (EPR) pairs. This protocol employs
only local operations and classical communication between the N parties
(N-LOCC). In particular, we rely on quantum data compression and teleportation
to create the desired state. This protocol can be used to obtain upper bounds
for the bipartite entanglement of formation of an arbitrary N-partite pure
state, in the asymptotic limit of many copies. We apply it to a few
multipartite states of interest, showing that in some cases it is not optimal.
Generalizations of the protocol are developed which are optimal for some of the
examples we consider, but which may still be inefficient for arbitrary states.Comment: 11 pages, 1 figure. Version 2 contains an example for which protocol
P3 is better than protocol P2. Correction to references in version
Perceptual-cognitive expertise in combat sport: from scientific research to training
[EN] Performance in combat sports has been widely studied from the point of view of physiology, anthropometrics or biomechanics
Mode-Wise Entanglement of Gaussian States
We address the decomposition of a multi-mode pure Gaussian state with respect
to a bi-partite division of the modes. For any such division the state can
always be expressed as a product state involving entangled two-mode squeezed
states and single mode local states at each side. The character of entanglement
of the state can therefore be understood modewise; that is, a given mode on one
side is entangled with only one corresponding mode of the other, and therefore
the total bi-partite entanglement is the sum of the modewise entanglement. This
decomposition is generally not applicable to all mixed Gaussian states.
However, the result can be extended to a special family of "isotropic" states,
characterized by a phase space covariance matrix with a completely degenerate
symplectic spectrum.Comment: 4 pages, RevTex4. Replaced with revised version with reference added
to a previous related paper. Minor typographical errors correcte
Phonon Density of States and Anharmonicity of UO2
Phonon density of states (PDOS) measurements have been performed on
polycrystalline UO2 at 295 and 1200 K using time-of-flight inelastic neutron
scattering to investigate the impact of anharmonicity on the vibrational
spectra and to benchmark ab initio PDOS simulations performed on this strongly
correlated Mott-insulator. Time-of-flight PDOS measurements include anharmonic
linewidth broadening inherently and the factor of ~ 7 enhancement of the oxygen
spectrum relative to the uranium component by the neutron weighting increases
sensitivity to the oxygen-dominated optical phonon modes. The first-principles
simulations of quasi-harmonic PDOS spectra were neutron-weighted and
anharmonicity was introduced in an approximate way by convolution with
wavevector-weighted averages over our previously measured phonon linewidths for
UO2 that are provided in numerical form. Comparisons between the PDOS
measurements and the simulations show reasonable agreement overall, but they
also reveal important areas of disagreement for both high and low temperatures.
The discrepancies stem largely from an ~ 10 meV compression in the overall
bandwidth (energy range) of the oxygen-dominated optical phonons in the
simulations. A similar linewidth-convoluted comparison performed with the PDOS
spectrum of Dolling et al. obtained by shell-model fitting to their historical
phonon dispersion measurements shows excellent agreement with the
time-of-flight PDOS measurements reported here. In contrast, we show by
comparisons of spectra in linewidth-convoluted form that recent
first-principles simulations for UO2 fail to account for the PDOS spectrum
determined from the measurements of Dolling et al. These results demonstrate
PDOS measurements to be stringent tests for ab initio simulations of phonon
physics in UO2 and they indicate further the need for advances in theory to
address lattice dynamics of UO2.Comment: Text slightly modified, results unchange
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