The role of rotation on Petersen Diagrams. The Pi1/0(Omega) Pi_{1/0}(Omega) period ratios

The present work explores the theoretical effects of rotation in calculating the period ratios of double-mode radial pulsating stars with special emphasis on high-amplitude delta Scuti stars (HADS). Diagrams showing these period ratios vs. periods of the fundamental radial mode have been employed as a good tracer of non-solar metallicities and are known as Petersen diagrams (PD).In this paper we consider the effect of moderate rotation on both evolutionary models and oscillation frequencies and we show that such effects cannot be completely neglected as it has been done until now. In particular it is found that even for low-to-moderate rotational velocities (15-50 km/s), differences in period ratios of some hundredths can be found. The main consequence is therefore the confusion scenario generated when trying to fit the metallicity of a given star using this diagram without a previous knowledge of its rotational velocity.Comment: A&A in pres

Intrinsic Magnetism in Nanosheets of SnO2_{2}: A First-principles Study

We propose intrinsic magnetism in nanosheets of SnO$_{2}$, based on first-principles calculations. The electronic structure and spin density reveal that $p$ orbitals of the oxygen atoms, surrounding Sn vacancies, have a non itinerant nature which gives birth to localized magnetism. A giant decrease in defect formation energies of Sn vacancies in nanosheets is observed. We, therefore, believe that native defects can be stabilized without any chemical doping. Nanosheets of different thicknesses are also studied, and it is found that it is easier to create vacancies, which are magnetic, at the surface of the sheets. SnO$_{2}$ nanosheets can, therefore, open new opportunities in the field of spintronics.Comment: J. Magn. Magn. Mate. 2012 (Accepted

Hyperonic crystallization in hadronic matter

Published in Hadrons, Nuclei and Applications, World Scientific, Singapore, Proc.of the Conference Bologna2000. Structure of the Nucleus at the Dawn of the Century, G. Bonsignori, M. Bruno, A. Ventura, D. Vretenar Editors, pag. 319.Comment: 4 pages, 2figure

Terahertz testing of very large scale integrated circuits

Growing sophistication of electronics devices and circuits and, especially of VLSI and ULSIC, presents increasing demands on circuit testing and fault diagnosis. The conventional well-established technique of electric AC and DC testing is costly, does not assure a complete fault identification. This technique also presents an additional security problem making it possible to design faked circuits avoiding the identification by this testing.1 Fabrication of and even perception of faked VLSI capable of surreptitious performance has become an increasing problem often referred to as “trojan hardware”. Experimental techniques, such as laser scanning2and terahertz imaging 3-5 have a limited resolution signal-to-noise ratios and encounter difficulties in defect identification. A new approach of THz testing of Microwave Monolithic Integrated Circuits (MMICs)6, VLSI, and ULSIC is based on measuring the circuit responses at the pins or input/output leads and comparing these responses with etalon responses. 7, 8 This technique could augment or replace the electrical testing and/or laser and THz scanning testing for production testing, burn-in testing, high temperature testing, and infant mortality testing. It could also be extended for the fault diagnosis and identification and for the lifetime and reliability predictions. To this end it could be augmented by the low noise measurements. The number of the detected responses could be very large, since the permutations of the voltages between the pins and leads could be measured at the different positions of the scanning THz beam, different THz frequencies and polarizations, in the pulsed and/or CW mode, at the different modulation frequencies and at the different THz intensities. This technique could be used under or without bias. The processing of these responses forming multi-dimensional images in the excitation parameter space could be processed using artificial intelligence algorithms and machine learning approaches making this testing technique self-learning and self-improving. This testing could be further improved by designing for testability by THz responses at the pins. Acknowledgements The work at RPI was supported by the U.S. Army Research Laboratory Cooperative Research Agreement (Project Monitor Dr. Meredith Reed) and by the Office of Naval Research (Project Monitor Dr. Paul Maki). References 1. D. Hély; K. Rosenfeld; R. Karri, Security challenges during VLSI test, 2011 IEEE 9th International New Circuits and systems conference, DOI: 10.1109/NEWCAS.2011.5981325s 2. Boscaro, A., Jacquir, S., Melendez, K., Sanchez, K., Perdu, P., and Binczak, S. (2016). Automatic process for time-frequency scan of VLSI. Microelectronics Reliability, 64, 299–305. doi:10.1016/j.microrel.2016.07.052 3. K. Ahi, S. Shahbazmohamadi, and N. Asadizanjani, “Quality control and authentication of packaged integrated circuits using enhanced-spatial-resolution terahertz time-domain spectroscopy and imaging,” Optics and Lasers in Engineering, vol. 104, pp. 274–284, 2018 4. M. Nagel and H. Kurz, Terahertz imaging: Terahertz reflectometry images faults in silicon chips, Laser Focus World, 11/01/2011 5. M. Yamashita, K. Kawase, C. Otani, T. Kiwa, and M. Tonouchi, Testing of large-scale integrated circuits using laser terahertz emission microscopy,” Opt. Exp., vol. 13, no. 1, pp. 115–120, Jan. 2005 6. S. Rumyantsev, A. Muraviev, S. Rudin, G. Rupper, M. Reed, J. Suarez and M. Shur, Terahertz Beam Testing of Millimeter Wave Monolithic Integrated Circuits, IEEE Sensors Journal, IEEE Sensors J., Vol. 17, No. Sep. 1, pp. 5487-5490 (2017) 7. G. Rupper, J. Suarez, S. Rudin, M. Reed, M. Shur, Terahertz plasmonics for testing very large-scale integrated circuits under bias, Patent Application Publication, No.: US 2018/0238961 Al, Pub. Date: Aug. 23, 2018 8. M. Shur, S. Rudin, G. Rupper, M. Reed, and J. Suarez, Sub-Terahertz Testing of Millimeter Wave Monolithic and Very Large Scale Integrated Circuits, Solid State Electronics (2019), to be publishe

From old wars to new wars and global terrorism

Even before 9/11 there were claims that the nature of war had changed fundamentally. The 9/11 attacks created an urgent need to understand contemporary wars and their relationship to older conventional and terrorist wars, both of which exhibit remarkable regularities. The frequency-intensity distribution of fatalities in "old wars", 1816-1980, is a power-law with exponent 1.80. Global terrorist attacks, 1968-present, also follow a power-law with exponent 1.71 for G7 countries and 2.5 for non-G7 countries. Here we analyze two ongoing, high-profile wars on opposite sides of the globe - Colombia and Iraq. Our analysis uses our own unique dataset for killings and injuries in Colombia, plus publicly available data for civilians killed in Iraq. We show strong evidence for power-law behavior within each war. Despite substantial differences in contexts and data coverage, the power-law coefficients for both wars are tending toward 2.5, which is a value characteristic of non-G7 terrorism as opposed to old wars. We propose a plausible yet analytically-solvable model of modern insurgent warfare, which can explain these observations.Comment: For more information, please contact [email protected] or [email protected]

Stripe formation in horizontally oscillating granular suspensions

We present the results of an experimental study of pattern formation in horizontally oscillating granular suspensions. Starting from a homogeneous state, the suspension turns into a striped pattern within a specific range of frequencies and amplitudes of oscillation. We observe an initial development of layered structures perpendicular to the vibration direction and a gradual coarsening of the stripes. However, both processes gradually slow down and eventually saturate. The probability distribution of the stripe width approaches a nonmonotonic steady-state form which can be approximated by a Poisson distribution. We observe similar structures in MD simulations of soft spherical particles coupled to the motion of the surrounding fluid.Comment: 7 pages, 8 figures, to appear in Europhys. Lett. (2014