1,241 research outputs found
A New Equation of State for CCS Pipeline Transport: Calibration of Mixing Rules for Binary Mixtures of CO2 with N2, O2 and H2
One of the aspects currently holding back commercial scale deployment of
carbon capture and storage (CCS) is an accurate understanding of the
thermodynamic behaviour of carbon dioxide and relevant impurities during the
pipeline transport stage. In this article we develop a general framework for
deriving pressure-explicit EoS for impure CO2. This flexible framework
facilitates ongoing development of custom EoS in response to new data and
computational applications. We use our method to generalise a recent EoS for
pure CO2 [Demetriades et al. Proc IMechE Part E, 227 (2013) pp. 117] to binary
mixtures with N2, O2 and H2, obtaining model parameters by fitting to
experiments made under conditions relevant to CCS-pipeline transport. Our model
pertains to pressures up to 16MPa and temperatures between 273K and the
critical temperature of pure CO2. In this region, we achieve close agreement
with experimental data. When compared to the GERG EoS, our EoS has a comparable
level of agreement with CO2 -N2 VLE experiments and demonstrably superior
agreement with the O2 and H2 VLE data. Finally, we discuss future options to
improve the calibration of EoS and to deal with the sparsity of data for some
impurities
Is government ownership of banks really harmful to growth?
We show that previous results suggesting that government ownership of banks has a negative effect on economic growth are not robust to adding more 'fundamental' determinants of economic growth, such as institutions. We also present regression results from a more recent period (1995-2007) which suggest that, if anything, government ownership of banks has been associated with higher long run growth rates, even after controlling for institutions and other variables suggested by the growth literature. Drawing on the current global financial crisis, we provide a conceptual framework which explains why under certain circumstances government owned banks could have a greater effect on economic growth than privately-owned banks
Government ownership of banks, institutions and financial development
Using a suitably modified locational model of banking, we examine the influence of institutions, such as deposit contract enforcement, in explaining the share of previous termgovernmentnext term owned previous termbanksnext term in the banking system. We present cross-country evidence suggesting that institutional factors are relatively more important determinants of the share of state previous termbanksnext term than political or historical ones. We argue that rather than privatizing or subsidizing state previous termbanks governmentsnext term in developing countries should build institutions that foster the development of private banking
Applied geochemistry in the twenty-first century: mineral exploration and environmental surveys
Applied (exploration and environmental) geochemistry in the twentieth century is briefly reviewed, and its future developments in the twenty-first century are envisaged in the light of advances in analytical instruments (laboratory and field) and computer technology. It is concluded that applied geochemical methods must be used by well-trained applied geochemists, and the potential for future developments is limited only by their ingenuity
The End of Financial Repression? A Cross-Country Analysis of Investment
We estimate a model of investment under financial restrains due to Demetriades and Devereux (2000), using total and private aggregate investment data from 38 high income and low income countries during 1972-2002. Our main findings for the overall sample are that (i) the US real interest rate is a robust determinant of total investment, suggesting that US monetary policy may have unintended global consequences; (ii) a term proxying domestic financial restraints is found to have an insignificant impact both on total and private investment. These findings are, however, somewhat less conclusive when we examine low income countries on their own, where financial restraints are found to have a negative and marginally significant effect on total investment.Financial restraints; investment; dynamic panel data
Modelling COâ transport and the effect of impurities: a new equation of state for CCS pipeline transport
In this EngD project I developed a new, analytic equation of state for use in the area of CCS pipeline transport. It was my aim to design a model which would exhibit a high degree of accuracy within the anticipated window of operation of CCS pipelines; from 260 to 335K and 1 to 200bar, whilst simultaneously retaining a simplicity and ease-of-use, a lack of which made some other available equations particularly unwieldy. Having conducted a comprehensive literature review and attended many academic and industrial conferences throughout this project, I felt that there was a need for an equation of state which could perform both these functions. This was the key motivation for my work, and the model presented in this thesis was developed in order that it might contribute towards negating the many concerns that currently surround the pipeline transport stage of CCS.
I aimed for the proposed model to display a complexity approaching that of some of the simpler equations currently available, whilst incorporating sucient flexibility to give thermodynamic predictions to a standard approaching that of those which are more complicated. I defined criteria by which the proposed model could be judged, so that it could be applied with condence in the determination of the physical properties of carbon dioxide mixtures during CCS pipeline transport.
Work was carried out by fitting the parameters of the proposed model to experimental data gathered from the literature, so that it would be able to determine the homogeneous phase pressure and vapour-liquid equilibrium behaviour of carbon dioxide and other relevant gas mixtures. The project yielded a number of excellent outputs, not least the satisfaction of the primary aim which was the proposal of a model, which through this EngD, I demonstrated had the ability to meet the demands that were set. In carrying out this work, I also developed several highly useful auxiliary mathematical methods which helped in ensuring the proposed model was as accurate as possible.
For the case of modelling pure carbon dioxide, the proposed equation worked exceptionally well, providing highly accurate predictions for homogeneous density and vapour liquid equilibrium, which were well within the targets set. A paper on this was published in May 2013. In extending the model to incorporate some binary mixtures I again found that it demonstrated a clear ability to capture the necessary physical behaviours within the target range. I concluded with suggestions as to ways in which the work presented here could be developed further, as well as the many avenues for future work in other areas that this EngD project had opened up
Injury patterns and outcomes in motorcycle driver crashes in the United States: The effect of helmet use.
BACKGROUND
Motorcycle crashes pose a persistent public health problem with disproportionate rates of severe injuries and mortality. This study aims to analyze injury patterns and outcomes with regard to helmet use. We hypothesized that helmet use is associated with fewer head injuries and does not increase the risk of cervical spine injuries.
METHODS
The National Trauma Data Bank was queried for all motorcycle driver crashes between 2007-2017. Univariable analysis was used to compare demographics, clinical data, injury patterns using abbreviated injury scale, and outcomes between helmeted motorcycle drivers and non-helmeted motorcycle drivers who were injured in traffic crashes. Independent factors associated with mortality were determined by regression analysis after adjustment for potential confounders.
RESULTS
A total of 315,258 patients were included for analysis, 66 % of these patients were helmeted. The sample was 92.5 % male and the median age was 41 years. Non-helmeted motorcycle drivers were more likely to sustain severe head trauma (head abbreviated injury scale âĽÂ 3: 28.5 % vs. 13.3 %, p < 0.001), had higher intensive care unit-admission (38 % vs. 30.2 %, p<0.001), mechanical ventilation (20.1 % vs. 13 %, p<0.001) and overall mortality rates (6.2 % vs. 3.9 %, p<0.001). Cervical spine injuries occurred in 10.6 % of non-helmeted motorcycle drivers and in 9.5 % of helmeted motorcycle drivers (p<0.001). Helmet use was identified as an independent factor associated with lower mortality [OR 0.849 (0.809-0.891), p<0.001].
CONCLUSION
Helmet use is protective for severe head injuries and associated with decreased mortality. Helmet use was not associated with increased rates of cervical spine injuries. On the contrary, fewer injuries were observed in helmeted motorcycle drivers. Public health initiatives should be aimed at enforcement of universal helmet laws within the United States and across the world
An assessment of patient-reported long-term outcomes following surgery for cauda equina syndrome
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