12,200 research outputs found
Flow properties of suspensions rich in solids
Mathematical evaluation of flow properties of fluids carrying high concentrations of solids in suspension relates suspension viscosity to physical properties of the solids and liquids, and provides a means for predicting flow behavior. A technique for calculating a suspensions flow rates is applicable to the design of pipelines
A brief review of low-dose rate (LDR) and high-dose rate (HDR) brachytherapy boost for high-risk prostate
For patients with unfavorable or high-risk prostate cancer, dose escalated radiation therapy leads to improved progression free survival but attempts to deliver increased dose by external beam radiation therapy (EBRT) alone can be limited by late toxicities to nearby genitourinary and gastrointestinal organs at risk. Brachytherapy is a method to deliver dose escalation in conjunction with EBRT with a potentially improved late toxicity profile and improved prostate cancer related outcomes. At least three randomized controlled trials have demonstrated improved biochemical control with the addition of either low-dose rate (LDR) or high-dose rate (HDR) brachytherapy to EBRT, although only ASCENDE-RT compared brachytherapy to dose-escalated EBRT but did report an over 50% improvement in biochemical failure with a LDR boost. Multiple single institution and comparative research series also support the use of a brachytherapy boost in the DE-EBRT era and demonstrate excellent prostate cancer specific outcomes. Despite improved oncologic outcomes with a brachytherapy boost in the high-risk setting, the utilization of both LDR, and HDR brachytherapy use is declining. The acute genitourinary toxicities when brachytherapy boost is combined with EBRT, particularly a LDR boost, are of concern in comparison to EBRT alone. HDR brachytherapy boost has many physical properties inherent to its rapid delivery of a large dose which may reduce acute toxicities and also appeal to the radiobiology of prostate cancer. We herein review the evidence for use of either LDR or HDR brachytherapy boost for high-risk prostate cancer and summarize comparisons between the two treatment modalities
Tip cap for a rotor blade
A replaceable tip cap for attachment to the end of a rotor blade is described. The tip cap includes a plurality of walls defining a compartment which, if desired, can be divided into a plurality of subcompartments. The tip cap can include inlet and outlet holes in walls thereof to permit fluid communication of a cooling fluid there through. Abrasive material can be attached with the radially outer wall of the tip cap
Gluon propagator in diffractive scattering
In this work, we perform a comparison of the employ of distinct gluon
propagators with the experimental data in diffractive processes, elastic
scattering and light meson photo-production. The gluon propagators are
calculated through non-perturbative methods, being justified their use in this
class of events, due to the smallness of the momentum transfer. Our results are
not able to select the best choice for the modified gluon propagator among the
analyzed ones, showing that the application of this procedure in this class of
high energy processes, although giving a reasonable fit to the experimental
data, should be taken with same caution.Comment: 14 pages, 4 figures, accepted for publication in Int. J. Mod. Phys. A
(uses ws-ijmpa.cls). Authors correcte
Arresting bubble coarsening: A two-bubble experiment to investigate grain growth in presence of surface elasticity
Many two-phase materials suffer from grain-growth due to the energy cost
which is associated with the interface that separates both phases. While our
understanding of the driving forces and the dynamics of grain growth in
different materials is well advanced by now, current research efforts address
the question of how this process may be slowed down, or, ideally, arrested. We
use a model system of two bubbles to explore how the presence of a finite
surface elasticity may interfere with the coarsening process and the final
grain size distribution. Combining experiments and modelling in the analysis of
the evolution of two bubbles, we show that clear relationships can be predicted
between the surface tension, the surface elasticity and the initial/final size
ratio of the bubbles. We rationalise these relationships by the introduction of
a modified Gibbs criterion. Besides their general interest, the present results
have direct implications for our understanding of foam stability
Un-reduction
This paper provides a full geometric development of a new technique called
un-reduction, for dealing with dynamics and optimal control problems posed on
spaces that are unwieldy for numerical implementation. The technique, which was
originally concieved for an application to image dynamics, uses Lagrangian
reduction by symmetry in reverse. A deeper understanding of un-reduction leads
to new developments in image matching which serve to illustrate the
mathematical power of the technique.Comment: 25 pages, revised versio
Spin- and angle-resolved photoemission studies of the electronic structure of Si(110)"16x2" surfaces
The electronic structure of Si(110)"16 x 2" double-domain, single-domain and
1 x 1 surfaces have been investigated using spin- and angle-resolved
photoemission at sample temperatures of 77 K and 300 K. Angle-resolved
photoemission was conducted using horizontally- and vertically-polarised 60 eV
and 80 eV photons. Band-dispersion maps revealed four surface states ( to
) which were assigned to silicon dangling bonds on the basis of measured
binding energies and photoemission intensity changes between horizontal and
vertical light polarisations. Three surface states (, and ),
observed in the Si(110)"16 x 2" reconstruction, were assigned to Si adatoms and
Si atoms present at the edges of the corrugated terrace structure. Only one of
the four surface states, , was observed in both the Si(110)"16 x 2" and 1
x 1 band maps and consequently attributed to the pervasive Si zigzag chains
that are components of both the Si(110)"16 x 2" and 1 x 1 surfaces. A state in
the bulk-band region was attributed to an in-plane bond. All data were
consistent with the adatom-buckling model of the Si(110)"16 x 2" surface.
Whilst room temperature measurements of and were statistically
compatible with zero, measurements of the enantiomorphic A-type and
B-type Si(110)"16 x 2" surfaces gave small average polarisations of around
1.5\% that were opposite in sign. Further measurements at 77 K on A-type
Si(110)"16 x 2" surface gave a smaller value of +0.3\%. An upper limit of
may thus be taken for the longitudinal polarisation.Comment: Main paper: 12 pages and 11 figures. Supplemental information: 5
pages and 2 figure
Analysis of surface waves generated on subwavelength-structured silver films
Using transmission electron microscopy (TEM) to analyse the physical-chemical
surface properties of subwavlength structured silver films and
finite-difference time-domain (FDTD) numerical simulations of the optical
response of these structures to plane-wave excitation, we report on the origin
and nature of the persistent surface waves generated by a single slit-groove
motif and recently measured by far-field optical interferometry. The surface
analysis shows that the silver films are free of detectable oxide or sulfide
contaminants, and the numerical simulations show very good agreement with the
results previously reported.Comment: 9 Figure
Palliative radiation therapy (RT) for prostate cancer patients with bone metastases at diagnosis: A hospitalâbased analysis of patterns of care, RT fractionation scheme, and overall survival
Spatial Symmetry of Superconducting Gap in YBa2Cu3O7-\delta Obtained from Femtosecond Spectroscopy
The polarized femtosecond spectroscopies obtained from well characterized
(100) and (110) YBa2Cu3O7-\delta thin films are reported. This bulk-sensitive
spectroscopy, combining with the well-textured samples, serves as an effective
probe to quasiparticle relaxation dynamics in different crystalline
orientations. The significant anisotropy in both the magnitude of the
photoinduced transient reflectivity change and the characteristic relaxation
time indicates that the nature of the relaxation channel is intrinsically
different in various axes and planes. By the orientation-dependent analysis,
d-wave symmetry of the bulk-superconducting gap in cuprate superconductors
emerges naturally.Comment: 8 pages, 4 figures. To be published in Physical Review B, Rapid
Communication
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