4,835 research outputs found
Nuclear incompressibility using the density dependent M3Y effective interaction
A density dependent M3Y effective nucleon-nucleon (NN) interaction which was
based on the G-matrix elements of the Reid-Elliott NN potential has been used
to determine the incompressibity of infinite nuclear matter. The nuclear
interaction potential obtained by folding in the density distribution functions
of two interacting nuclei with this density dependent M3Y effective interaction
had been shown earlier to provide excellent descriptions for medium and high
energy and heavy ion elastic scatterings as well as and heavy
cluster radioactivities. The density dependent parameters have been chosen to
reproduce the saturation energy per nucleon and the saturation density of spin
and isospin symmetric cold infinite nuclear matter. The result of such
calculations for nuclear incompressibility using the density dependent M3Y
effective interaction based on the G-matrix elements of Reid-Elliott NN
potential predicts a value of about 300 MeV for nuclear incompressibility.Comment: 4 Page
Two-Loop Corrections to the Neutral Higgs Boson Masses in the CP-Violating NMSSM
We present our calculation of the two-loop corrections of to the neutral Higgs boson masses of the CP-violating
Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM). The
calculation is performed in the Feynman diagrammatic approach in the gaugeless
limit at vanishing external momentum. We apply a mixed
-on-shell (OS) renormalization scheme for the NMSSM
input parameters. Furthermore, we exploit a as well as
an OS renormalization in the top/stop sector. The corrections are implemented
in the Fortran code NMSSMCALC for the calculation of the Higgs spectrum both in
the CP-conserving and CP-violating NMSSM. The code also provides the Higgs
boson decays including the state-of-the-art higher-order corrections. The
corrections computed in this work improve the already available corrections in
NMSSMCALC which are the full one-loop corrections without any approximation and
the two-loop corrections in the gaugeless limit
and at vanishing external momentum. Depending on the chosen parameter point, we
find that the corrections add about
4-7% to the one-loop mass of the SM-like Higgs boson for
renormalization in the top/stop sector and they reduce
the mass by about 6-9% if OS renormalization is applied. For an estimate of the
theoretical uncertainty we vary the renormalization scale and change the
renormalization scheme and show that care has to be taken in the corresponding
interpretation
GEODYN programmer's guide, volume 2, part 2
A computer program for executive control routine for orbit integration of artificial satellites is presented. At the beginning of each arc, the program initiates required constants as well as the variational partials at epoch. If epoch needs to be reset to a previous time, the program negates the stepsize, and calls for integration backward to the desired time. After backward integration is completed, the program resets the stepsize to the proper positive quantity
Crack propagation in concrete at very early ages
Surface defects and cracks in early-age concrete slabs have been observed to propagate under adverse conditions, impairing the performance and service life of these structures. However, the underlying mechanism of this form of crack propagation has remained largely unexplained, with very limited literature available. In this paper, simple yet sufficiently rigorous theoretical analyses of crack propagation in early-age concrete slabs, based on combined geotechnical engineering and fracture mechanics models, are presented. The results obtained clearly show how surface cracks can become unstable and propagate further, and either become stable again or develop through the full depth of the slab. They also convincingly demonstrate the roles of surface cracks and defects, pore moisture suctions and exposure conditions in this process. Importantly, the critical role of good construction practices in minimising this form of cracking is highlighted. These include proper compaction and effective curing as well as timely and adequate saw-cutting
Plastic cracking of concrete: The roles of osmotic and matric suctions
Plastic cracking of concrete is primarily attributable to desiccation by evaporation from unprotected surfaces. This causes high matric suctions to develop in the pore water in the voids adjacent to these surfaces. Dissolved salts in the pore water generate osmotic suctions. However, the effects of these suctions on the strength of plastic concrete are imperfectly understood. In this paper, equations describing total (matric plus osmotic) and osmotic suctions and the shear strength of desiccated particulate materials are discussed briefly. The development of suctions in desiccating fly ash and their effect on its shear strength are illustrated by experimental data. These show that matric suctions do but osmotic suctions do not affect the shear strength of fly ash and hence of comparable materials, including plastic concrete
Spectral and Energy Efficiency Maximization for Content-Centric C-RANs with Edge Caching
This paper aims to maximize the spectral and energy efficiencies of a content-centric cloud radio access network (C-RAN), where users requesting the same contents are grouped together. Data are transferred from a central baseband unit to multiple remote radio heads (RRHs) equipped with local caches. The RRHs then send the received data to each group's user. Both multicast and unicast schemes are considered for data transmission. We formulate mixed-integer nonlinear problems in which user association, RRH activation, data rate allocation, and signal precoding are jointly designed. These challenging problems are subject to minimum data rate requirements, limited fronthaul capacity, and maximum RRH transmit power. Employing successive convex quadratic programming, we propose iterative algorithms with guaranteed convergence to Fritz John solutions. Numerical results confirm that the proposed joint designs markedly improve the spectral and energy efficiencies of the considered content-centric C-RAN compared to benchmark schemes. Importantly, they show that unicasting outperforms multicasting in terms of spectral efficiency in both cache and cache-less scenarios. In terms of energy efficiency, multicasting is the best choice for the system without cache whereas unicasting is best for the system with cache. Finally, edge caching is shown to improve both spectral and energy efficiencies.This work is supported in part by an ECRHDR scholarship from The University of Newcastle, in part by the Australian Research Council Discovery Project grants DP170100939 and DP160101537
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