418 research outputs found
Phase Transitions in High Purity Zr Under Dynamic Compression
We present results from ramp compression experiments on high-purity Zr that
show the , , as well as
reverse phase transitions. Simulations with a
multi-phase equation of state and phenomenological kinetic model match the
experimental wave profiles well. While the dynamic
transition occurs GPa above the equilibrium phase boundary, the
transition occurs within 0.9~GPa of equilibrium. We
estimate that the dynamic compression path intersects the equilibrium line at GPa, and K. The thermodynamic path in the
interior of the sample lies K above the isentrope at the point of
the transition. Approximately half of this
dissipative temperature rise is due to plastic work, and half is due to the
non-equilibrium transition. The inferred rate of
the transition is several orders of magnitude
higher than that measured in dynamic diamond anvil cell (DDAC) experiments in
an overlapping pressure range. We discuss a model for the influence of shear
stress on the nucleation rate. The small fractional volume change at the transition amplifies the effect
of shear stress, and we estimate that for this case shear stress is equivalent
to a pressure increase in the range of several GPa. Correcting our transition
rate to a hydrostatic rate brings it approximately into line with the DDAC
results, suggesting that shear stress plays a significant role in the
transformation rate
Excited Hydroxyl Outflow in the High-Mass Star-Forming Region G34.26+0.15
G34.26+0.15 is a region of high-mass star formation that contains a broad
range of young stellar objects in different stages of evolution, including a
hot molecular core, hyper-compact HII regions and a prototypical cometary
ultra-compact HII region. Previous high-sensitivity single dish observations by
our group resulted in the detection of broad 6035 MHz OH absorption in this
region; the line showed a significant blue-shifted asymmetry indicative of
molecular gas expansion. We present high-sensitivity Karl G. Jansky Very Large
Array (VLA) observations of the 6035 MHz OH line conducted to image the
absorption and investigate its origin with respect to the different star
formation sites in the region. In addition, we report detection of 6030 MHz OH
absorption with the VLA and further observations of 4.7 GHz and 6.0 GHz OH
lines obtained with the Arecibo Telescope. The 6030 MHz OH line shows a very
similar absorption profile as the 6035 MHz OH line. We found that the 6035 MHz
OH line absorption region is spatially unresolved at " scales, and it
is coincident with one of the bright ionized cores of the cometary HII region
that shows broad radio recombination line emission. We discuss a scenario where
the OH absorption is tracing the remnants of a pole-on molecular outflow that
is being ionized inside-out by the ultra-compact HII region.Comment: 19 pages, 6 figures. Accepted for publication in The Astrophysical
Journa
Reading remittance landscapes: Female migration and agricultural transition in the Philippines
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Hot startup experience with electrometallurgical treatment of spent nuclear fuel
The treatment of spent metal fuel from the EBR-II fast reactor commenced in June of 1996 at the Fuel Conditioning Facility on the Argonne-West site in Idaho, USA. During the first year of hot operations, 20 fuel assemblies entered processing and 6 low enrichment uranium product ingots were produced. Results are presented for the various process steps with decontamination factors achieved and equipment operational history reported
Is the Shroud of Turin in Relation to the Old Jerusalem Historical Earthquake?
Phillips and Hedges suggested, in the scientific magazine Nature (1989), that
neutron radiation could be liable of a wrong radiocarbon dating, while proton
radiation could be responsible of the Shroud body image formation. On the other
hand, no plausible physical reason has been proposed so far to explain the
radiation source origin, and its effects on the linen fibres. However, some
recent studies, carried out by the first author and his Team at the Laboratory
of Fracture Mechanics of the Politecnico di Torino, found that it is possible
to generate neutron emissions from very brittle rock specimens in compression
through piezonuclear fission reactions. Analogously, neutron flux increments,
in correspondence to seismic activity, should be a result of the same
reactions. A group of Russian scientists measured a neutron flux exceeding the
background level by three orders of magnitude in correspondence to rather
appreciable earthquakes (4th degree in Richter Scale). The authors consider the
possibility that neutron emissions by earthquakes could have induced the image
formation on Shroud linen fibres, trough thermal neutron capture by Nitrogen
nuclei, and provided a wrong radiocarbon dating due to an increment in
C(14,6)content. Let us consider that, although the calculated integral flux of
10^13 neutrons per square centimetre is 10 times greater than the cancer
therapy dose, nevertheless it is100 times smaller than the lethal dose.Comment: 13 pages, 1 figur
The complexities, coordination, culture and capacities that characterise the delivery of oncology services in the common areas of ambulatory settings.
BACKGROUND: Relatively little is understood about real-world provision of oncology care in ambulatory outpatient clinics (OPCs). This study aimed to: 1) develop an understanding of behaviours and practices inherent in the delivery of cancer services in OPC common areas by characterising the organisation and implementation of this care; and 2) identify barriers to, and facilitators of, the delivery of this care in OPC common areas. METHODS: A purpose-designed ethnographic study was employed in four public hospital OPCs. Informal field scoping activities were followed by in-situ observations, key informant interviews and document review. A view of OPCs as complex adaptive systems was used as a scaffold for the data collection and interpretation, with the intent of understanding 'work as done'. Data were analysed using an adapted "Qualitative Rapid Appraisal, Rigorous Analysis" approach. RESULTS: Field observations were conducted over 135âh, interviews over 6.5âh and documents were reviewed. Analysis found six themes. Staff working in OPCs see themselves as part of small local teams and as part of a broader multidisciplinary care team. Professional role boundaries could be unclear in practice, as duties expanded to meet demand or to stop patients "falling through the cracks." Formal care processes in OPCs were supported by relationships, social capital and informal, but invaluable, institutional expertise. Features of the clinic layout, such as the proximity of departments, affected professional interactions. Staff were aware of inter- and intra-service communication difficulties and employed strategies to minimise negative impacts on patients. We found that complexity, coordination, culture and capacity underpin the themes that characterise this care provision. CONCLUSIONS: The study advances understanding of how multidisciplinary care is delivered in ambulatory settings and the factors which promote or inhibit effective care practice. Time pressures, communication challenges and competing priorities can pose barriers to care delivery. OPC care is facilitated by: self-organisation of participants; professional acumen; institutional knowledge; social ties and relationships between and within professional groups; and commitment to patient-centred care. An understanding of the realities of 'work-as-done' may help OPCs to sustain high-quality care in the face of escalating service demand
'Sending Dollars Shows Feeling' - Emotions and Economies in Filipino Migration
This paper analyses the conceptualization of gender, relationships, and emotions that underpin âcare chainsâ approaches to Filipino labour migration. In a case study of longâdistance intimacy and economic transfers in an extended Filipino family, I show how contextualizing migration within local understandings of emotion fractures expectations created by care chains accounts. This case instead reveals agency, diversity, and new forms of global subjectivity emerging through longâdistance emotional connections within the translocal field shaped by labour mobility
Providing outpatient cancer care for CALD patients: a qualitative study
Objective
There have been few descriptions of how outpatient cancer care is provided to patients from culturally and linguistically diverse (CALD) communities. As populations who experience disparities in cancer care access and outcomes, deeper understanding is needed to help identify those factors which can shape the receipt of multidisciplinary care in ambulatory settings. This paper reports on data collected and analysed as part of a multicentre characterisation of care in Australian public hospital cancer outpatient clinics (OPCs).
Results
Analysis of data from our ethnographic study of four OPCs identified three themes: âIdentifying CALD patient language-related needsâ; âCapacity and resources to meet CALD patient needsâ, and âMaking it work for CALD communities.â The care team comprises not only clinicians but also families and non-clinical staff; OPCs serve as âtouchpointsâ facilitating access to a range of therapeutic services. The findings highlight the potential challenges oncology professionals negotiate in providing care to CALD communities and the ways in which clinicians adapt their practices, formulate strategies and use available resources to support care delivery
"The Great Event of the Fortnightâ: Steamship Rhythms and Colonial Communication
This paper engages with Tim Cresswellâs âcontellations of mobilityâ in order to contribute some understanding of historical maritime rhythms. The empirical focus is upon a steamship mail service in the post-emancipation Caribbean. In examining this communications network, it is stressed that while those managing the network valorised predictable efficiency, âfrictionâ was prized by mercantile groups at the steamersâ ports of call. Thus, the different aspects of mobility signified differently across the network, and this historical case study reinforces the resonance of slowness and stoppage time. The synchronisation of steamship arrivals with sociocultural norms in the Caribbean colonies also necessitated the adaptation of mail service rhythms. Through a focus on shipping operations, this paper proposes to temper our understanding of the role of steamship technology in empire. The influence of colonies on the metropole encompassed an alteration of the rhythms of imperial circulation, and it is within the maritime arena that these realities came into sharp focus
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IFR Fuel Cycle Demonstration in the EBR-II Fuel Cycle Facility
The next major milestone of the IFR program is engineering-scale demonstration of the pyroprocess fuel cycle. The EBR-II Fuel Cycle Facility has just entered a startup phase which includes completion of facility modifications, and installation and cold checkout of process equipment. This paper reviews the design and construction of the facility, the design and fabrication of the process equipment, and the schedule and initial plan for its operation. 5 refs., 4 figs
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