1,320 research outputs found
Coronal and chromospheric physics
Achievements and completed results are discussed for investigations covering solar activity during the solar maximum mission and the solar maximum year; other studies of solar activity and variability; infrared and submillimeter photometry; solar-related atomic physics; coronal and transition region studies; prominence research; chromospheric research in quiet and active regions; solar dynamics; eclipse studies; and polarimetry and magnetic field measurements. Contributions were also made in defining the photometric filterograph instrument for the solar optical telescope, designing the combined filter spectrograph, and in expressing the scientific aims and implementation of the solar corona diagnostic mission
From a few to many electrons in quantum dots under strong magnetic fields: Properties of rotating electron molecules with multiple rings
Using the method of breaking of circular symmetry and of subsequent symmetry
restoration via projection techiques, we present calculations for the
ground-state energies and excitation spectra of N-electron parabolic quantum
dots in strong magnetic fields in the medium-size range 10 <= N <= 30. The
physical picture suggested by our calculations is that of finite rotating
electron molecules (REMs) comprising multiple rings, with the rings rotating
independently of each other. An analytic expression for the energetics of such
non-rigid multi-ring REMs is derived; it is applicable to arbitrary sizes given
the corresponding equilibrium configuration of classical point charges. We show
that the rotating electron molecules have a non-rigid (non-classical)
rotational inertia exhibiting simultaneous crystalline correlations and
liquid-like (non-rigidity) characteristics. This mixed phase appears in high
magnetic fields and contrasts with the picture of a classical rigid Wigner
crystal in the lowest Landau level.Comment: REVTEX4, 15 pages with 12 figures. Accepted for publication in
Physical Review B. To download a file with figures of higher quality, click
http://www.prism.gatech.edu/~ph274cy/ (go to publication #72
Coronal and chromospheric physics
The Solar Maximum Mission support program is mentioned along with investigations of the solar corona, prominences, and chromosphere. The solar limb was studied using far infrared and submillimeter photometry. Stokes profiles obtained from sunspot observations were examined with a polarimetric technique
The role of the mental health practitioner in divorce and custody litigation
Bibliography: pages 189-208.Two elements have been isolated as having a profound effect on the adjustment of children and families to post-divorce life. These are the hostility expressed and experienced before, during and after the divorce, and the losses experienced as a result of the final settlement terms. Based on a review of the historical development of family law and the more recent reforms adopted throughout the Western World, the present shortfalls of the South African system of family law in providing for the needs of children and families in divorce have been identified. A model of dissolution is presented which aims primarily at the reduction of the hostility and loss thus experienced. This includes the evaluation and updating of the 'best interests' standard used by the courts for arriving at custody/access settlements and a detailed discussion of the role played by the mental health professional at each stage of the dissolution process. The roles explored here include that of counsellor and facilitator in the pre-divorce, mediation and post-divorce stages; and the role of investigator/consultant and expert witness in the court process
Deep Learning networks with p-norm loss layers for spatial resolution enhancement of 3D medical images
Thurnhofer-Hemsi K., López-Rubio E., Roé-Vellvé N., Molina-Cabello M.A. (2019) Deep Learning Networks with p-norm Loss Layers for Spatial Resolution Enhancement of 3D Medical Images. In: Ferrández Vicente J., Álvarez-Sánchez J., de la Paz López F., Toledo Moreo J., Adeli H. (eds) From Bioinspired Systems and Biomedical Applications to Machine Learning. IWINAC 2019. Lecture Notes in Computer Science, vol 11487. Springer, ChamNowadays, obtaining high-quality magnetic resonance (MR) images is a complex problem due to several acquisition factors, but is crucial in order to perform good diagnostics. The enhancement of the resolution is a typical procedure applied after the image generation. State-of-the-art works gather a large variety of methods for super-resolution (SR), among which deep learning has become very popular during the last years. Most of the SR deep-learning methods are based on the min-
imization of the residuals by the use of Euclidean loss layers. In this paper, we propose an SR model based on the use of a p-norm loss layer to improve the learning process and obtain a better high-resolution (HR) image. This method was implemented using a three-dimensional convolutional neural network (CNN), and tested for several norms in order to determine the most robust t. The proposed methodology was trained and tested with sets of MR structural T1-weighted images and showed
better outcomes quantitatively, in terms of Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index (SSIM), and the restored and the calculated residual images showed better CNN outputs.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Numerical simulation of colloidal dispersion filtration: description of critical flux and comparison with experimental results
During filtration via membrane processes, colloids accumulate at the porous surface leading to fouling phenomena. In this study, a rigorous simulation of momentum and mass transfer using CFD modelling has been developed to describe such an accumulation during cross flow filtration. These simulations integrate detailed modeling of physicochemical properties specific to colloidal dispersions (because of the surface interactions (repulsive and attractive) occurring between the colloids particles). These interactions are accounted for via the experimental variation of the colloidal osmotic pressure with volume fraction (associated with a variation in the diffusion coefficient) which are fitted by a relationship integrated into the CFD code. It contains a description of the colloidal phase transition leading to the formation of a condensed phase (deposit or gel layer) from the accumulated dispersed phase (concentration polarization). It is then possible to determine the critical flux which separates filtration conditions below which mass accumulation is reversible (in the dispersed phase) and above which it is irreversible (in the condensed phase). The computed value of critical flux is compared with that determined experimentally for a dispersion of latex particles
Premelting of Thin Wires
Recent work has raised considerable interest on the nature of thin metallic
wires. We have investigated the melting behavior of thin cylindrical Pb wires
with the axis along a (110) direction, using molecular dynamics and a
well-tested many-body potential. We find that---in analogy with cluster
melting---the melting temperature of a wire with radius is lower
than that of a bulk solid, , by . Surface melting
effects, with formation of a thin skin of highly diffusive atoms at the wire
surface, is observed. The diffusivity is lower where the wire surface has a
flat, local (111) orientation, and higher at (110) and (100) rounded areas. The
possible relevance to recent results on non-rupturing thin necks between an STM
tip and a warm surface is addressed.Comment: 10 pages, 4 postscript figures are appended, RevTeX, SISSA Ref.
131/94/CM/S
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