7,277 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
A concurrent precursor inflow method for Large Eddy Simulations and applications to finite length wind farms
In order to enable simulations of developing wind turbine array boundary
layers with highly realistic inflow conditions a concurrent precursor method
for Large Eddy Simulations is proposed. In this method we consider two domains
simultaneously, i.e. in one domain a turbulent Atmospheric Boundary Layer (ABL)
without wind turbines is simulated in order to generate the turbulent inflow
conditions for a second domain in which the wind turbines are placed. The
benefit of this approach is that a) it avoids the need for large databases in
which the turbulent inflow conditions are stored and the correspondingly slow
I/O operations and b) we are sure that the simulations are not negatively
affected by statically swept fixed inflow fields or synthetic fields lacking
the proper ABL coherent structures. Sample applications are presented, in
which, in agreement with field data a strong decrease of the power output of
downstream wind-turbines with respect to the first row of wind-turbines is
observed for perfectly aligned inflow.Comment: 13 pages, 5 figure
An Infrared Camera for Leuschner Observatory and the Berkeley Undergraduate Astronomy Lab
We describe the design, fabrication, and operation of an infrared camera
which is in use at the 30-inch telescope of the Leuschner Observatory. The
camera is based on a Rockwell PICNIC 256 x 256 pixel HgCdTe array, which is
sensitive from 0.9-2.5 micron. The primary purpose of this telescope is for
undergraduate instruction. The cost of the camera has been minimized by using
commercial parts whereever practical. The camera optics are based on a modified
Offner relay which forms a cold pupil where stray thermal radiation from the
telescope is baffled. A cold, six-position filter wheel is driven by a
cryogenic stepper motor, thus avoiding any mechanical feed throughs. The array
control and readout electronics are based on standard PC cards; the only custom
component is a simple interface card which buffers the clocks and amplifies the
analog signals from the array.Comment: 13 pages, 17 figures. Submitted to Publications of the Astronomical
Society of the Pacific: 2001 Jan 10, Accepted 2001 Jan 1
Condoms are more effective when applied by males: a study of young black males in the United States
PurposeTo determine, among a sample of young black male (YBM), whether female application of male condoms for penile–vaginal intercourse would be associated with higher or lower rates of breakage or slippage. A secondary aim was to investigate if higher rates of breakage or slippage were associated with increased odds of acquiring chlamydia and/or gonorrhea.MethodsA cross-sectional study of 412 YBM, aged 15 to 23 years, was conducted in three US cities located in the Southern United States.ResultsAmong YBM reporting frequent female application of condoms, 43.5% reported one or more instance of breakage or slippage, compared with those reporting less frequent female application (27.2%, P = .003). Among YBM reporting one or more event of breakage or slippage, 25.4% tested positive for chlamydia and/or gonorrhea. In contrast, among those not reporting breakage or slippage, 17.2% tested positive (P = .047).ConclusionsFindings suggest that educational and behavioral interventions should seek to improve young women's skills relative to condom application and use. Further studies could also investigate whether intervention efforts should encourage some YBM to be responsible for their own condom application
Coarse-grained simulations of flow-induced nucleation in semi-crystalline polymers
We perform kinetic Monte Carlo simulations of flow-induced nucleation in
polymer melts with an algorithm that is tractable even at low undercooling. The
configuration of the non-crystallized chains under flow is computed with a
recent non-linear tube model. Our simulations predict both enhanced nucleation
and the growth of shish-like elongated nuclei for sufficiently fast flows. The
simulations predict several experimental phenomena and theoretically justify a
previously empirical result for the flow-enhanced nucleation rate. The
simulations are highly pertinent to both the fundamental understanding and
process modeling of flow-induced crystallization in polymer melts.Comment: 17 pages, 6 eps figure
Impact of caring for someone with a rare rheumatic condition, views from patients and informal carers – the need for cat-like vigilance
Objective
ANCA-associated vasculitis (AAV) is a rare multisystem disease. Modern therapeutic protocols have turned AAV from an acute frequently fatal disease into a chronic disease requiring long-term immunosuppression. Patients must often manage substantial burdens related to chronic illness and treatment-related side effects, requiring help from informal carers. This study aimed to explore the experience of patients and of informal carers of patients with AAV about the impact of managing a rare rheumatic condition.
Methods
A qualitative approach using semi-structured interviews was used. Interviews were conducted with a purposeful sample of 18 pairs of patients with AAV and their informal carers. The interviews were used to explore the participants’ experience and effects of caring. The interviews were recorded and transcribed as verbatim text and analysed using the framework technique.
Results
18 patients (seven female) [disease: ten granulomatosis with polyangiitis (GPA); four microscopic polyangiitis (MPA); four eosinophilic granulomatosis with polyangiitis (EGPA), age range 34-78, disease duration 1- 20 years. Caregiver and patient perspectives were shared. The emerging themes were the physical and psychological impact of the disease, the need for constant vigilance and fear of the future.
Conclusion
Both patients and carers faced a range of challenges in managing a rare condition, from the seriousness of the illness, dealing with the emotional toll and knowing what to expect. This study offers insight into the experiences of patients and informal carers, and health care professionals should address individuals’ fears and expectations for recovery
Investigating intra-host and intra-herd sequence diversity of foot-and-mouth disease virus
Due to the poor-fidelity of the enzymes involved in RNA genome replication, foot-and-mouth disease (FMD) virus samples comprise of unique polymorphic populations. In this study, deep sequencing was utilised to characterise the diversity of FMD virus (FMDV) populations in 6 infected cattle present on a single farm during the series of outbreaks in the UK in 2007. A novel RT–PCR method was developed to amplify a 7.6 kb nucleotide fragment encompassing the polyprotein coding region of the FMDV genome. Illumina sequencing of each sample identified the fine polymorphic structures at each nucleotide position, from consensus level changes to variants present at a 0.24% frequency. These data were used to investigate population dynamics of FMDV at both herd and host levels, evaluate the impact of host on the viral swarm structure and to identify transmission links with viruses recovered from other farms in the same series of outbreaks. In 7 samples, from 6 different animals, a total of 5 consensus level variants were identified, in addition to 104 sub-consensus variants of which 22 were shared between 2 or more animals. Further analysis revealed differences in swarm structures from samples derived from the same animal suggesting the presence of distinct viral populations evolving independently at different lesion sites within the same infected animal
275 Impact of caring for someone with a rare rheumatic condition: views from patients and informal carers
Background: ANCA-associated vasculitis is a rare multisystem
disease. Modern therapeutic protocols have turned ANCA-associated
vasculitis from an acute frequently fatal disease into a chronic disease
requiring long-term immunosuppression. Patients must often manage
substantial burdens related to chronic illness and treatment-related
side effects. Patients often need help and support to manage their
disease. The aim of this study was to explore the experience of
patients and of informal carers of patients about the impact of
managing a rare rheumatic condition.
Methods: A qualitative approach using semi-structured interviews
was used. Interviews were conducted with a purposeful sample of 18
pairs of patients with ANCA-associated vasculitis and their informal
carers. The interviews were used to explore the participants
experience and affects of caring. The interviews were recorded and
transcribed as verbatim text and analysed using the framework
technique.
Results: 18 patients (seven female) [disease: ten granulomatosis with
polyangiitis (GPA); four microscopic polyangiitis (MPA); four eosinophilic
granulomatosis with polyangiitis (EGPA), age range 34-78,
disease duration 1- 20 years. Caregiver and patient perspectives
were shared. The emerging themes were the physical and psychological
impact of the disease, the need for constant vigilance and fear of
the future.
Conclusion: Both patients and carers faced a range of challenges in
managing a rare condition. From the seriousness of the illness, dealing
with the emotional toll and knowing what to expect. This study offers
insight into the experiences of patients and informal carers and health
care professionals should address individuals’ fears and expectations
for recovery.
Disclosures: J.M. honoraria; Abbvie, Bristol Myres Squibb. K.G. and
R.A.W. have declared no conflicts of interest
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