Towards a unification of HRT and SCOZA. Analysis of exactly solvable mean-spherical and generalized mean-spherical models

The hierarchical reference theory (HRT) and the self-consistent Ornstein-Zernike approximation (SCOZA) are two liquid state theories that both furnish a largely satisfactory description of the critical region as well as the phase coexistence and equation of state in general. Furthermore, there are a number of similarities that suggest the possibility of a unification of both theories. Earlier in this respect we have studied consistency between the internal energy and free energy routes. As a next step toward this goal we here consider consistency with the compressibility route too, but we restrict explicit evaluations to a model whose exact solution is known showing that a unification works in that case. The model in question is the mean spherical model (MSM) which we here extend to a generalized MSM (GMSM). For this case, we show that the correct solutions can be recovered from suitable boundary conditions through either of SCOZA or HRT alone as well as by the combined theory. Furthermore, the relation between the HRT-SCOZA equations and those of SCOZA and HRT becomes transparent.Comment: Minimal correction of some typos found during proof reading. Accepted for publication in Phys. Rev.

Comparisons of global topographic/isostatic models to the Earth's observed gravity field

The Earth's gravitational potential, as described by a spherical harmonic expansion to degree 180, was compared to the potential implied by the topography and its isostatic compensation using five different hypothesis. Initially, series expressions for the Airy/Heiskanen topographic isostatic model were developed to the third order in terms of (h/R), where h is equivalent rock topography and R is a mean Earth radius. Using actual topographic developments for the Earth, it was found that the second and third terms of the expansion contributed 30 and 3 percents, of the first of the expansion. With these new equations it is possible to compute depths (D) of compensation, by degree, using 3 different criteria. The results show that the average depth implied by criterion I is 60 km while it is about 33 km for criteria 2 and 3 with smaller compensation depths at the higher degrees. Another model examined was related to the Vening-Meinesz regional hypothesis implemented in the spectral domain. Finally, oceanic and continental response functions were derived for the global data sets and comparisons made to locally determined values

Capture and release of a conditional state of a cavity QED system by quantum feedback

Detection of a single photon escaping an optical cavity QED system prepares a nonclassical state of the electromagnetic field. The evolution of the state can be modified by changing the drive of the cavity. For the appropriate feedback, the conditional state can be captured (stabilized) and then released. This is observed by a conditional intensity measurement that shows suppression of vacuum Rabi oscillations for the length of the feedback pulse and their subsequent return

Strategies for Financing Large-scale Carbon Capture and Storage Power Plants in China

Building on previous stakeholder consultations from 2006 to 2010, we conduct a financial analysis for a generic CCS power plant in China. In comparison with conventional thermal generation technologies, a coal-fired power plant with CCS requires either a 70% higher on-grid electricity tariff or carbon price support of approximately US$50/tonne CO2 in the absence of any other incentive mechanisms or financing strategies. Given the difficulties of relying on any one single measure to finance a large-scale CCS power plant in China, we explore a combination of possible financing mechanisms. Potential measures available for increasing the return on the CCS investment include: enhanced oil recovery (EOR), a premium electricity tariff, and operational investment flexibility (e.g. solvent storage, upgradability). A simulation found that combining several financing options could not only provide private investors with a 12% to 18% return on equity (ROE), but also significantly reduce the required on-grid tariff to a level that is very close to the tariff level of existing coal-fired power plants and much lower than the tariffs for natural gas combined cycle and nuclear power plants. Therefore, we suggest that a combination of existing financing measures could trigger private investment in a large-scale CCS power plant in China

A comparison of public preferences for different low-carbon energy technologies: Support for CCS, nuclear and wind energy in the United Kingdom

Using a representative national survey in the United Kingdom, we investigated public attitudes towards different low-carbon technologies (carbon capture and storage (CCS), wind and nuclear power) and the factors influencing public support. Overall, we found that respondents were far more likely to support wind energy as their preferred means of mitigating climate change. Older people and those of a higher social grade are more supportive of nuclear power, while age and social grade do not significantly affect support for wind energy. Supporters of the Conservative Party were more likely to oppose wind power. Neither attitudes towards climate change nor environmental attitudes were found to influence public support for wind power or nuclear. Trust in information from environmental groups was associated with greater support for wind energy but lower support for nuclear power. Perceived cost and objective knowledge significantly influenced public support for all three technology types, that is, higher perceived costs and the poorer objective knowledge lead to lower public support. However, self-assessed knowledge did not influence public support. Many factors, including most of the tested demographic factors, did not affect support for any of the three technologies