Effect of pressure cycling on Iron: Signatures of an electronic instability and unconventional superconductivity

High pressure electrical resistivity and x-ray diffraction experiments have been performed on Fe single crystals. The crystallographic investigation provides direct evidence that in the martensitic $bcc \rightarrow hcp$ transition at 14 GPa the $\lbrace 110\rbrace_{bcc}$ become the $\lbrace 002\rbrace_{hcp}$ directions. During a pressure cycle, resistivity shows a broad hysteresis of 6.5 GPa, whereas superconductivity, observed between 13 and 31 GPa, remains unaffected. Upon increasing pressure an electronic instability, probably a quantum critical point, is observed at around 19 GPa and, close to this pressure, the superconducting $T_{c}$ and the isothermal resistivity ($0<T<300\,$K) attain maximum values. In the superconducting pressure domain, the exponent $n = 5/3$ of the temperature power law of resistivity and its prefactor, which mimics $T_{c}$, indicate that ferromagnetic fluctuations may provide the glue for the Cooper pairs, yielding unconventional superconductivity

An Iterative Cyclic Algorithm for Designing Vaccine Distribution Networks in Low and Middle-Income Countries

The World Health Organization's Expanded Programme on Immunization (WHO-EPI) was developed to ensure that all children have access to common childhood vaccinations. Unfortunately, because of inefficient distribution networks and cost constraints, millions of children in many low and middle-income countries still go without being vaccinated. In this paper, we formulate a mathematical programming model for the design of a typical WHO-EPI network with the goal of minimizing costs while providing the opportunity for universal coverage. Since it is only possible to solve small versions of the model optimally, we describe an iterative heuristic that cycles between solving restrictions of the original problem and show that it can find very good solutions in reasonable time for larger problems that are not directly solvable.Comment: International Joint Conference on Industrial Engineering and Operations Management- ABEPRO-ADINGOR-IISE-AIM-ASEM (IJCIEOM 2019). Novi Sad, Serbia, July 15-17t

Connection between accretion disk and superluminal radio jets and the role of radio plateau state in GRS 1915+105

We investigate the association between the accretion disk during radio plateau state and the following superluminal relativistic radio jets with peak intensity varies from 200 mJy to 1000 mJy observed over a period of five years and present the evidences of direct accretion disc-jet connection in microquasar GRS 1915+105. We have analysed RXTE PCA/HEXTE X-ray data and have found that the accretion rate, $\dot{m}_{accr}$, as inferred from the X-ray flux, is very high during the radio plateaux. We suggest that the accretion disk during the radio plateaux always associated with radiation-driven wind which is manifested in the form of enhanced absorption column density for X-ray and the depleted IR emission. We find that the wind density increases with the accretion disk luminosity during the radio plateaux. The wind density is similar to the density of the warm absorber proposed in extragalactic AGNs and Quasars. We suggest a simple model for the origin of superluminal relativistic jets. Finally, We discuss the implications of this work for galactic microquasars and the extragalactic AGNs and Quasars.Comment: 9 pages, 6 Figures, Accepted for publication in Ap

Analysis and Interpretation of In-Phase Component of VLF-EM Data using Hilbert Transform and the Amplitude of Analytical Signal

An interpretation of in-phase anomaly of very low frequency electromagnetic (VLF-EM) data was carried out using the analysis of the Hilbert transform of the in-phase component and the amplitude of its analytic signal. The analysis was used to delineate the source and depth to the top of a subsurface conductive body. The amplitude of the analytical signal of the data was observed to mimic the conventional Fraser-filtered operation and was used to locate the exact location of the anomalous body. The in-phase component with the Hilbert transform yields an approximate depth to the top of the conductor which agree with the result of the vertical electrical sounding conducted at the vicinity of the anomalous body. Keywords: VLF-EM method, Hilbert transform, analytical signal, in-phase, Fraser filtering