3,931 research outputs found
Method of tracing contour patterns for use in making gradual contour resin matrix composites
The invention relates to methods for making alminate patterns for a resin matrix composite structural component. A sheet of paper is temporarily adhered to a model of the structrual component. A pen is positioned on the paper with a spindle touching the model surface opposite the pen. The pen and spindle are moved along the path that maintains the aforementioned contacts. The resulting line traced on paper is a model constant-thickness locus and provides a pattern for a single lamination of resin-impregnated fabric. The steps are repeated to make other patterns and each time the steps are repeated the distance between the tracer and the spindle is changed to correspond to the thickness of a lamination
Molding procedure for casting a variety of alloys
General procedure and molding sand composition for preparing molds usable for casting variety of alloys are developed. Molds are prepared from mixture of sand, sodium silicate binder, and organic liquid ester. Castings of radiographic quality are produced from various alloys
in the complex two Higgs doublet model
The latest LHC data confirmed the existence of a Higgs-like particle and made
interesting measurements on its decays into , , , , and . It is expected that a decay into might be measured at the next LHC round, for which there already exists
an upper bound. The Higgs-like particle could be a mixture of scalar with a
relatively large component of pseudoscalar. We compute the decay of such a
mixed state into , and we study its properties in the context of the
complex two Higgs doublet model, analysing the effect of the current
measurements on the four versions of this model. We show that a measurement of
the rate at a level consistent with the SM can be used
to place interesting constraints on the pseudoscalar component. We also comment
on the issue of a wrong sign Yukawa coupling for the bottom in Type II models.Comment: 31 pages, 15 figure
A reappraisal of the wrong-sign coupling and the study of
It has been pointed out recently that current experiments still allow for a
two Higgs doublet model where the coupling () is
negative; a sign opposite to that of the Standard Model. Due to the importance
of delayed decoupling in the coupling, improved measurements will have a strong impact on this issue. For the
same reason, measurements or even bounds on are
potentially interesting. In this article, we revisit this problem, highlighting
the crucial importance of , which can be understood with
simple arguments. We show that the impacts on models of both and are very sensitive to
input values for the gluon fusion production mechanism; in contrast, and are not. We also
inquire if the search for and its interplay with will impact the sign of the coupling.
Finally, we study these issues in the context of the Flipped two Higgs doublet
model.Comment: 13 pages, pdf figure
The K-process on a tree as a scaling limit of the GREM-like trap model
We introduce trap models on a finite volume -level tree as a class of
Markov jump processes with state space the leaves of that tree. They serve to
describe the GREM-like trap model of Sasaki and Nemoto. Under suitable
conditions on the parameters of the trap model, we establish its infinite
volume limit, given by what we call a -process in an infinite -level
tree. From this we deduce that the -process also is the scaling limit of the
GREM-like trap model on extreme time scales under a fine tuning assumption on
the volumes.Comment: Published in at http://dx.doi.org/10.1214/13-AAP937 the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Non-Equilibrium Modeling of the Fe XVII 3C/3D ratio for an Intense X-ray Free Electron Laser
We present a review of two methods used to model recent LCLS experimental
results for the 3C/3D line intensity ratio of Fe XVII (Bernitt et al. 2012),
the time-dependent collisional-radiative method and the density-matrix
approach. These are described and applied to a two-level atomic system excited
by an X-ray free electron laser. A range of pulse parameters is explored and
the effects on the predicted Fe XVII 3C and 3D line intensity ratio are
calculated. In order to investigate the behavior of the predicted line
intensity ratio, a particular pair of A-values for the 3C and 3D transitions
was chosen (2.22 10 s and 6.02 10
s for the 3C and 3D, respectively), but our conclusions are independent
of the precise values. We also reaffirm the conclusions from Oreshkina et
al.(2014, 2015): the non-linear effects in the density matrix are important and
the reduction in the Fe XVII 3C/3D line intensity ratio is sensitive to the
laser pulse parameters, namely pulse duration, pulse intensity, and laser
bandwidth. It is also shown that for both models the lowering of the 3C/3D line
intensity ratio below the expected time-independent oscillator strength ratio
has a significant contribution due to the emission from the plasma after the
laser pulse has left the plasma volume. Laser intensities above W/cm are required for a reduction in the 3C/3D line intensity
ratio below the expected time independent oscillator strength ratio
A line-binned treatment of opacities for the spectra and light curves from neutron star mergers
The electromagnetic observations of GW170817 were able to dramatically
increase our understanding of neutron star mergers beyond what we learned from
gravitational waves alone. These observations provided insight on all aspects
of the merger from the nature of the gamma-ray burst to the characteristics of
the ejected material. The ejecta of neutron star mergers are expected to
produce such electromagnetic transients, called kilonovae or macronovae.
Characteristics of the ejecta include large velocity gradients, relative to
supernovae, and the presence of heavy -process elements, which pose
significant challenges to the accurate calculation of radiative opacities and
radiation transport. For example, these opacities include a dense forest of
bound-bound features arising from near-neutral lanthanide and actinide
elements. Here we investigate the use of fine-structure, line-binned opacities
that preserve the integral of the opacity over frequency. Advantages of this
area-preserving approach over the traditional expansion-opacity formalism
include the ability to pre-calculate opacity tables that are independent of the
type of hydrodynamic expansion and that eliminate the computational expense of
calculating opacities within radiation-transport simulations. Tabular opacities
are generated for all 14 lanthanides as well as a representative actinide
element, uranium. We demonstrate that spectral simulations produced with the
line-binned opacities agree well with results produced with the more accurate
continuous Monte Carlo Sobolev approach, as well as with the commonly used
expansion-opacity formalism. Additional investigations illustrate the
convergence of opacity with respect to the number of included lines, and
elucidate sensitivities to different atomic physics approximations, such as
fully and semi-relativistic approaches.Comment: 27 pages, 22 figures. arXiv admin note: text overlap with
arXiv:1702.0299
The current status of hepatic transplantation at the University of Pittsburgh.
Tacrolimus is a more potent and satisfactory immunosuppressant than CyA for combination therapy with prednisone. In randomized trials comparing the 2 drugs, the ability of tacrolimus to rescue intractably rejecting grafts on the competing CyA arm allowed equalization of patient and graft survival on both arms when the intent-to-treat analytic methodology was applied. The ability of tacrolimus to systematically rescue the treatment failures of CyA suggested, as a matter of common sense, that it is the preferred baseline drug for hepatic transplantation. This conclusion was supported by analysis of secondary end points, including the ability to prevent rejection. Hepatic-intestinal, multivisceral and isolated intestinal transplantation became feasible on a practical basis only after the advent of tacrolimus. Nevertheless, better management strategies must be devised before intestinal transplantation, alone or with other abdominal viscera, will meet its potential. One such strategy is based on the discovery of the presence of previously unsuspected, low-level donor leukocyte chimerism in long-surviving allograft recipients. We believe that this chimerism is the essential explanation for the feasibility of organ transplantation and a link to the acquired neonatal tolerance demonstrated by Billingham, Brent and Medawar (32). The hematolymphopoietic chimerism in organ recipients explains why weaning to a drug-free state in selected long-term survivors is frequently feasible and particularly if the allograft is a liver. Weaning should never be attempted without a stepwise protocol and careful monitoring of graft function. Recognition of the natural chimerism that develops after whole organ transplantation has led to efforts to augment it with perioperative donor BM infusion. This procedure has been shown to be free of significant complications (including GVHD) in all kinds of whole organ recipients, including those given intestine. The prospects of clinical xenotransplantation must be evaluated in the same context of chimerism as that delineated for allotransplantation with the discovery of spontaneous chimerism. Before addressing chimerism-related questions in xenotransplantation, the additional barrier of the complement activation syndromes that cause hyperacute rejection will have to be surmounted. Although measures to effectively transplant xenografts have so far eluded us, the availability of the more potent drug, tacrolimus, and recognition of the seminal basis of allograft (or xenograft) acceptance via chimerism has inserted an element of reality into the largely wishful thinking that has been evident in discussions about the future of xenotransplantation
From eremitical to monastic settlements, from rural towards urban areas: the spatial evolution of the Portuguese eremitical congregation of São Paulo da Serra de Ossa
The Portuguese Eremitical Congregation of São Paulo da Serra de Ossa was founded in 1482, combining a large number of eremitical settlements that had been documented since 1366, mainly in the Alentejo region (southern Portugal), under a centralised government. In 1578, an autonomous congregation was set up and became affiliated with the Hungarian Order of Saint Paul the First Hermit. This paper aims to analyse the impact of the transition
from eremitical to monastic settlements, in terms of both settlement location and architectural typology.
The 17 case studies presented in this paper have been identi ed in the geographical region in question. A census of the existing physical structures – sometimes scant remains only – was carried out through literature reviews, archival research and on-site morphological and spatial analyses, allowing for a critical interpretation to be gained of the monastic landscapes. This article shall serve to discuss the implications of the transition from the eremitical
movement to the institutionalisation of the settlements, both in terms of their geography and spatial adaptations made as a result of these changes.info:eu-repo/semantics/publishedVersio
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