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Physical Sciences, Astronomy & Astrophysics; Milgrom’s acceleration constant; Bekenstein-Hawking entropy; gravitational dipole; dark matter
Online: 12 December 2018 (14:36:52 CET)
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Conceiving vacuum energy as gravitational particles subject to Heisenberg’s energy-time uncertainty, modelled as dipoles in a fluidal space at thermodynamic equilibrium, and interpreting the Bekenstein-Hawking entropy as the effective amount of spins of those dipoles enclosed within the event horizon of the universe, allows the calculation of Milgrom’s acceleration constant. The result is a quantum mechanical interpretation of gravity, and dark matter in particular.
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Physical Sciences, Astronomy & Astrophysics; Dark matter; galaxies; gravitation; rotation curves; galaxy rotation period
Online: 12 December 2018 (12:49:30 CET)
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It is well known but under-appreciated in astrophysical applications, that it is possible for gravity to take on a life of its own in the form of Weyl-curvature-only metrics (note we are referring to the Weyl-only solutions of ordinary General Relativity, we are not considering Weyl conformal gravity or any other modified gravity theories), as numerous examples demonstrate the existence of gravitational fields not being sourced by any matter. In the weak field limit, such autonomous gravitational contents of our universe manifest as solutions to the homogeneous Poisson's equation. In this note, we tentatively explore the possibility that they may perhaps account for some phenomenologies commonly attributed to dark matter. Specifically, we show that a very simple solution of this kind exists that can be utilized to describe the rising tails seen in many galaxy rotation curves, which had been difficult to reconcile within the cold dark matter or modified Newtonian dynamics frameworks. This solution may also help explain the universal $\sim 1$Gyr rotation periods of galaxies in the local universe.
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Physical Sciences, Atomic & Molecular Physics; one-center method, molecular orbital, higher harmonics, excited state, ionized state, linear molecule, hydrogen fluoride, lithium monofluoride, boron monofluoride
Online: 11 December 2018 (09:37:53 CET)
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Modern development of high-intensity and high-resolution X-ray technology allows detailed studies of the multiphoton absorption and scattering of X-ray photons by deep and subvalent shells of molecular systems on a wide energy range. The interpretation of experimental data requires the improvement of computational methods for obtaining excited and ionized electron states of molecular systems with one or several vacancies. The specificity of solving these problems requires the use of molecular orbitals obtained in one-center representation. Slow convergence of one-center expansions is a significant disadvantage of this approach; it affects the accuracy of the calculation of spectroscopic quantities. We offer a method of including higher harmonics in one-center expansion of a molecular orbital with the use of wave functions of electrons of deep shells of a ligand (off-center atom of a molecule). The method allows one to take into account correctly electron density of a linear molecule near the ligand when describing vacancies created in a molecular core leading to radial relaxation of electron density. The analysis of the parameters of one-center expansion of the ligand functions depending on ligand’s charge is performed. The criteria for the inclusion of higher harmonics of one-center decomposition of the ligand functions in the molecular orbital are determined. The efficiency of the method is demonstrated by the example of diatomic molecules HF, LiF, and BF by estimating energy characteristics of their ground and ionized states.
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Physical Sciences, Applied Physics; 3D nano-lithography, 3D laser lithography, direct laser writing, nanopolymerization, cross-linking, multi-photon absorption, avalanche ionization, temperature effects
Online: 11 December 2018 (09:31:31 CET)
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Direct laser writing three-dimensional nano-lithography is an established technique for manufacturing functional 3D micro- and nano-objects via non-linear absorption induced polymerization process. In this Chapter an underlying physical mechanisms taking place during nano-confined polymerization reaction, induced by tightly focused ultra-short laser pulses, are reviewed and discussed. The special
attention is paid on the effects that directly impact structuring resolution and minimum achievable feature size. Analysis of possible photo-initiation mechanisms as contributing multi-photon absorption and avalanche ionization in pre-polymers under diverse exposure conditions (wavelength, pulse duration) is presented. Feasible structuring of pure (non-photosensitized) and functional nanoparticles doped polymer precursors is justified and benefits of such materials/structures for microoptics, photonics and cell scaffolds are highlighted. The influence of temperature effects (induced by writing process itself or determined by ambient conditions) on polymerization process, observed in different pre-polymers under diverse exposure regimes is outlined. The further adjustment of the structuring resolution is possible via precise control of light polarization and diffusion assisted radical quenching. The work is concluded with a brief outlook on future challenges and perspectives related to refinement of 3D ultra-fast laser lithography fabrication process in the means of application of diverse post-processing methods and research into novel photo-curable materials including inorganic ones.
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Physical Sciences, Applied Physics; biothermodynamics; complex systems; thermodynamics of biological systems; biophysical resonance
Online: 11 December 2018 (08:59:47 CET)
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From a thermodynamic point of view, living cell life is no more than a cyclic process. It starts with the newly separated daughter cells and restarts when the next generations grow as free entities. In this cycle the cell changes its entropy. In cancer the growth control is damaged. In this paper we analyze the role of the volume-area ratio in cell in relation to the heat exchange between cell and its environment in order to point out the effect on the cancer growth. The result holds to a possible control of the cancer growth based on the heat exchanged by the cancer towards its environment, and the membrane potential variation, with the consequence of controlling the ions fluxes and the related biochemical reactions. This second law approach could represent a starting point for a possible future support for the anticancer therapies, in order to improve their effectiveness for the untreatable cancers.
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Physical Sciences, General & Theoretical Physics; Special relativity theory, length contraction, Planck length, Planck time, trans-Planck
Online: 10 December 2018 (13:43:34 CET)
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In gravity theory, there is a well-known trans-Planckian problem, which is that general relativity theory leads to a shorter than Planck length and shorter than Planck time in relation to so-called black holes. However, there has been little focus on the fact that special relativity also leads to a trans-Planckian problem, something we will demonstrate here. According to special relativity, an object with mass must move slower than light, but special relativity has no limits on how close to the speed of light something with mass can move. This leads to a scenario where objects can undergo so much length contraction that they will become shorter than the Planck length as measured from another frame, and we can also have shorter time intervals than the Planck time. The trans-Planckian problem is easily solved by a small modi cation that assumes Haug's maximum velocity for matter is the ultimate speed limit for something with mass. This speed limit depends on the Planck length, which can be measured without any knowledge of Newton's gravitational constant or the Planck constant. After a long period of slow progress in theoretical physics, we are now in a Klondike "gold rush" period where many of the essential pieces are falling in place.
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Physical Sciences, Optics; Quantum Rayleigh emission; Phase-sensitive amplification; Integrated photonic devices
Online: 10 December 2018 (11:34:56 CET)
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Despite multiple classical outcomes arising from the quantum Rayleigh conversions of photons underlying the propagation of optical waves through dielectric media and the ensuing light-matter interactions, this quantum process has been largely ignored. Several of its outcomes are considered in this article from a physical perspective, e.g., inter-quadrature coupling of photons, phase-dependent amplification in optical directional couplers and related polarization rotation, phase-shifting of weak signals in the optically linear regime, location-dependent coupling coefficient for refractive index gratings, etc. A correct identification of these effects will enable useful design and operation of integrated photonic functional devices.
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Physical Sciences, Fluids & Plasmas; homogeneous and heterogeneous reactions; hall and ion-slip currents; nanofluid; MHD; partially ionized
Online: 6 December 2018 (08:47:53 CET)
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Homogeneous and heterogeneous chemical reactions in partially ionized magneto-nano-liquid are investigated theoretically using finite element method (FEM). The effects of ions and electrons collisions on the transport of heat and mass are analyzed for both the cases of heterogeneous and homogeneous chemical reactions. The simultaneous effects of dispersion of nanosized particles in partially ionized nano-liquid in the presence of magnetic field are also investigated. Through numerical experiments, it is noted that the temperature of partially ionized nano-liquid increases when electrons collision rate and ion collisions are increased. The transport rate of reacting species decreases when heterogeneous and homogeneous chemical reactions strengths are increased. It is also observed that the effect of electron collisions on the flow in y-direction is the same to that of ion collisions on the flow in y-direction. Homogeneous and heterogeneous chemical reactions have similar effects on concentration of chemically reacting species in qualitative sense. However, in quantitative sense, homogeneous chemical reaction has more significant effect on the concentration reacting species as compared to heterogeneous chemical reaction.
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Physical Sciences, Atomic & Molecular Physics; quantum gravity; vacuum polarization; gravitational dipole; Majorana particle
Online: 4 December 2018 (09:54:13 CET)
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In this article various heuristic approaches are discussed to solve the dark matter phenomenon by the concept of vacuum polarization. They are compared with a more fundamental approach, based upon an entropy model of the visible universe. They all make use of some kind of gravitational dipole. These dipoles seem to violate Einstein’s equivalence principle between inertial mass and gravitational mass. It is shown how the paradox can be solved by a quantum mechanical principle.
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Physical Sciences, Particle & Field Physics; NA61/SHINE, upgrade, open charm, silicon detector, TPC, CERN long shutdown 2
Online: 4 December 2018 (09:24:42 CET)
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The NA61/SHINE experiment studies hadron production in hadron-hadron, hadron-nucleus and nucleus-nucleus collisions. The physics programme includes the study of the onset of deconfinement and search for the critical point as well as reference measurements for neutrino and cosmic ray experiments. For strong interactions, future plans are to extend the programme of study of the onset of deconfinement by measurements of open-charm and possibly other short-lived, exotic particle production in nucleus-nucleus collisions. This new programme is planned to start after 2020 and requires upgrades to the present NA61/SHINE detector setup. Besides the construction of a large acceptance silicon detector, a 10-fold increase of the event recording rate is foreseen, which will necessitate a general upgrade of most detectors.
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Physical Sciences, Optics; Optical Fibers, Numerical Methods, Resonance
Online: 3 December 2018 (16:10:43 CET)
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We provide a very general review of the resonant transmission line method for optical fiber problems. The method has been found to work seamlessly for a variety of difficult problems including elliptical and eccentric core fibers as well as “holey”, photonic crystal fibers. A latest version has been shown to offer great versatility with respect to cases of unconventional, inhomogeneous index profiles.
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Physical Sciences, Particle & Field Physics; neutrino mass; Planck neutrino mass limit; Higgs metastability; SMASH model
Online: 3 December 2018 (08:09:38 CET)
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Five fundamental problems—neutrino mass, baryogenesis, dark matter, inflation, strong CP problem—are solved at one stroke in a model, dubbed as “SM-A-S-H” (Standard Model-Axion-Seesaw-Higgs portal inflation) by Andreas Ringwald et. al. The Standard Model (SM) particle content is extended by three right-handed SM-singlet neutrinos $N_i$, a vector-like color triplet quark $Q$, a complex SM-singlet scalar field $\sigma$ that stabilises the Higgs potential, all of them being charged under Peccei-Quinn (PQ) $U(1)$ symmetry, the vacuum expectation value $v_\sigma\sim10^{11}$ GeV breaks the lepton number and the Peccei-Quinn symmetry simultaneously. We found that numerically SMASH model not only solves five fundamental problems but also the sixth problem “Vacuum Metastability” through the extended scalar sector and can predict approximately correct atmospheric neutrino mass splitting around 0.05 eV and the solar neutrino mass splitting around 0.009 eV.
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Physical Sciences, Astronomy & Astrophysics; universe expansion law; redshifts; distances; history of science
Online: 2 December 2018 (10:18:30 CET)
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Based on historical facts, revisited from a present-day perspective, and on the documented opinions of the scientists involved in the discovery themselves, strong arguments are given in favor of a proposal to include prominent astronomer Vesto Slipher to the suggested addition of Georges Lemaître's name to Hubble's law on the expansion of the Universe, and thus eventually call it Hubble-Lemaître-Slipher's (HLS) law.
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Physical Sciences, Condensed Matter Physics; new superconductivity, condensation state, new electric field, current emission, new type capacitor, Aharonov–Bohm effect, new energy source
Online: 30 November 2018 (15:57:10 CET)
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We previously reported new superconductivity produced by an electrostatic field and a diffusion current in a semiconductor without refrigeration. In particular, the superconductivity was investigated theoretically and confirmed experimentally. Here, we determine that the derived superconducting quantum state can be reproduced in a capacitor. When circuits are formed with this new-type capacitor and diodes, a magnetic field is applied to the diodes’ depletion layer. The depletion layer is biased because of the conversion from the magnetic-field energy to electric-field energy, resulting in the diodes’ spontaneously emitting a current. Thus, the new-type capacitor is charged using no other energy source. This new phenomenon is described theoretically with assistance of initial experiments.
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Physical Sciences, Particle & Field Physics; Neutrino oscillations; neutrino mixing; long baseline
Online: 30 November 2018 (11:07:53 CET)
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We study the possibility of determining the octant of the neutrino mixing angle 23, that is, whether 23 > 45 or 23 < 45, in long baseline neutrino experiments. Here we numerically derived the sensitivity limits within which these experiments can determine, by measuring the probability of the ! e transitions, the octant of 23 with a 5 certainty. The interference of the CP violation angle with these limits, as well as the effects of the baseline length and the run-time ratio of neutrino and antineutrino modes of the beam have been analyzed.
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Physical Sciences, Particle & Field Physics; hedgehogs; topological defects; multiple point principle
Online: 30 November 2018 (10:23:29 CET)
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Assuming the Multiple Point Principle (MPP) as a new law of Nature, we considered the existence of the two degenerate vacua of the Universe: a) the first Electroweak (EW) vacuum at $v_1\approx 246$ GeV—“true vacuum”, and b) the second Planck scale “false vacuum” at $v_2 \sim 10^{18}$ GeV. In these vacua, we investigated different topological defects. The main aim of the paper is an investigation of the black-hole-hedgehogs configurations as defects of the false vacuum. In the framework of the $f(R)$ gravity, described by the Gravi-Weak unification model, we considered a black-hole solution, which corresponds to a “hedgehog”—global monopole, that has been “swallowed” by the black-hole with mass core $M_{BH}\sim 10^{18}$ GeV and radius $\delta\sim 10^{-21}$ GeV$^{-1}$. Considering the results of the hedgehog lattice theory in the framework of the $SU(2)$ Yang-Mills gauge-invariant theory with hedgehogs in the Wilson loops, we have used the critical value of temperature for the hedgehogs’ confinement phase ($T_c\sim 10^{18}$ GeV). This result gave us the possibility to conclude that the SM shows a new physics (with contributions of the $SU(2)$-triplet Higgs bosons) at the scale $\sim 10$ TeV. This theory predicts the stability of the EW-vacuum and the accuracy of the MPP.
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Physical Sciences, Astronomy & Astrophysics; String, Cosmological, Bianchi Type III, Magnetic Field, Vacuum Energy Density.
Online: 30 November 2018 (10:13:50 CET)
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Bianchi type III string cosmological models (massive and geometric) in presence of magnetic field with vacuum energy density following the techniques used by Letelier (1979) and Stachel (1980) are obtained. We find that the energy conditions (dominant as well as weak) given by Hawking and Ellis (1974) are satisfied for the models. Also the solutions obtained satisfy conservation equation for massive string with magnetic field and vacuum energy density. The models in general, represent anisotropic phase of space-time due to the presence of string. However, the models isotropize at late time and in special case. It has also been shown that the magnetic field is directly linked with the matter. For string dust model, the state finder parameters {r,s} are in excellent agreement with Planck results (Sahni et al. (2003)). The physical and geometrical aspects of the models with special cases are also discussed.
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Physical Sciences, Other; organic solar cells; perovskite solar cells; encapsulation; stability
Online: 30 November 2018 (09:38:24 CET)
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Photovoltaic is one of the promising renewable sources of power to meet the future challenge of energy need. Organic and perovskite thin film solar cells are an emerging cost-effective photovoltaic technology because of low-cost manufacturing processing and a light-weight. The main barrier of commercial use of organic and perovskite solar cells is the poor stability of devices. Encapsulation of these photovoltaic devices is one of the best ways to address this stability issue and enhance the device lifetime by employing materials and structures that possess high barrier performance for oxygen and moisture. The aim of this review paper is to find different encapsulation materials and techniques for perovskite and organic solar cells according to the present understanding of reliability issues. It discusses the available encapsulate materials and their utility in limiting chemicals such as water vapour, oxygen penetration. It also covers the mechanisms of mechanical degradation within the individual layers and solar cell as a whole, and possible obstacles to their application in both organic and perovskite solar cells. The contemporary understanding of these degradation mechanisms, their interplay and their initiating factors (both internal and external) are also discussed.
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Physical Sciences, Astronomy & Astrophysics; hypothesis; collision; heavy post-post-fe elements; solar system
Online: 28 November 2018 (04:57:01 CET)
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Most people are unaware that traditional models do not explain chemical composition of the solar system fully. The presence of such elements as certain p-nuclei or post-post-Fe-nuclei, remains not yet understood. We propose a mechanism which can explain appearance of all non-native elements in the solar system. The hypothesis involves an explosive “collision” of a traveling from afar giant-nuclear-drop-like object (with specific equation of state of its matter) within the inner part of the solar system. The “nuclear fog” and debris, through the multitude of reaction channels (capture and fission) and nuclei transformations, enriched the solar system and led to the eventual formation of the terrestrial planets that pre-collision did not exist. This offers a possible explanation for the planets’ inner position and compositional differences within the predominantly hydrogen-helium rest of the solar system.
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Physical Sciences, Other; authentic learning; work integrated learning; curriculum development; laboratory classes; proxemics
Online: 27 November 2018 (05:20:40 CET)
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The traditional hands-on nature in science laboratory classes creates a sense of immediacy and a presence of authenticity in such learning experiences. The handling of physical objects in a laboratory class, and the immediate responses provided by these experiments, are certainly real-live observations, yet may be far from instilling an authentic learning experience in students. This paper explores the presence of authenticity in hands-on laboratory classes in introductory science laboratories. With our own laboratory program as a backdrop we introduce four general types of hands-on laboratory experiences and assign degrees of authenticity according the processes and student engagement associated with them. We present a newly developed type of hands-on experiment which takes a somewhat different view of the concept of hands-on in a laboratory class. A proxemics-based study of teacher-student interactions in the hands-on laboratory classes presents us with some insights into the design of the different types of laboratory classes and the pedagogical presumptions we made. A step-by-step guide on how to embed industry engagement in the curriculum and the design of an authentic laboratory program is presented to highlight some minimum requirement for the sustainability of such program and pitfalls to avoid.
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Physical Sciences, Mathematical Physics; tensor; gradient; divergence; curl; elasto-plastic deformation
Online: 27 November 2018 (04:00:29 CET)
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To extend the calculation power of tensor analysis, we introduce four new definition of tensor calculations. Some useful tensor identities have been proved. We demonstrate the application of the tensor identities in continuum mechanics: momentum conservation law and deformation superposition.
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Guglielmo Baccani,
Lorenzo Bonechi,
Massimo Bongi,
Debora Brocchini,
Nicola Casagli,
Roberto Ciaranfi,
Luigi Cimmino,
Vitaliano Ciulli,
Raffaello D'Alessandro,
Chiara Del Ventisette,
Andrea Dini,
Giovanni Gigli,
Sandro Gonzi,
Silvia Guideri,
Luca Lombardi,
Barbara Melon,
Massimiliano Nocentini,
Pasquale Noli,
Nicola Mori,
Giulio Saracino,
Lorenzo Viliani
Physical Sciences, Nuclear & High Energy Physics; muon radiography; cosmic rays; tracking detectors; imaging; geophysical prospection; mining
Online: 26 November 2018 (14:09:10 CET)
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Muon radiography is an imaging technique based on the measurement of the absorption of cosmic ray muons. This technique has recently been used successfully to investigate the presence of unknown cavities in the Bourbon Gallery in Naples and in the Cheops Pyramid at Cairo. The MIMA detector (Muon Imaging for Mining and Archaeology) is a muon tracker prototype for the application of muon radiography in the Archaeological and Mining fields. It is made of three couples of X-Y planes each consisting of 21 scintillator bars with silicon photomultiplier read-out. The detector is compact, robust, easily transportable and has a low power consumption: all of that makes the detector ideal for measurements in narrow and isolated environments. With this detector we have performed a measurement from inside the Temperino mine in the San Silvestro archaeo-mining park in Tuscany. The park includes about 25 km of mining tunnels arranged on several levels that have been excavated since the Etruscan time. The measured muon absorption was compared to the simulated one, obtained from the information provided by 3D laser scanner measurements and the cartographic maps of the mountain above the mine, in order to obtain information on the average density of the rock. This allowed to confirm the presence of a partially accessible exploitation opening and gave some hints on the presence of a high density body within the rock.
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Physical Sciences, Astronomy & Astrophysics; Artificial Intelligence, Brain Simulation
Online: 26 November 2018 (11:34:04 CET)
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We introduce a mission design for an interstellar expedition to nearby earth-like exoplanets, which our analysis determined to be Tau Ceti and Gliese 667C, at the time of analysis in 2013. We review the research problems in propulsion and AGI that must be addressed to launch an AI guided interstellar probe within 100 years. We propose a new semi-autonomous agent approach for intelligent control of the spacecraft. We introduce the concept of a semi-autonomous agent as having built-in safety guarantees that constrain operation. An autonomous agent case study is presented formulating the objective, constraints, AGI implementation of the agent based on Solomono 's Alpha architecture, and adding speci city. We discuss the training required to reach human-level and trans-sapient levels of intelligence which corresponds to an entire crew of AI experts specialized in elds such as astrophysics, astromechanics, astrobiology, quantum physics, computer science, molecular biology, and so forth. We project the feasibility of the human-level AI technology based on empirical ndings in neuroscience, and nd that it should be feasible by 2030. We analyze Solomono 's in nity point hypothesis in light of Koomey's law about energy eciency of computing and nd that the trends in 2013 indicated an early singularity by 2035, which implies that we might encounter physical bottlenecks which will decelerate computing technology improvements signi cantly. We recommend thus year 2040 for launching the probe by which date other required technologies will have been developed. We discuss the scenario of a virtual crew made of brain simulations, which is a bio-information based AI approach. We detail the subsystems of command and control, communication, scienti c instrumentation, power, propulsion, navigation, and shielding. We propose a variation of ICAN-II/AIMStar propulsion which uses a positron source instead of anti-protons to initiate micro-fusion reactions. We combine the positron initiated fusion pulse propulsion scheme with a miniaturized version of the Daedelus fusion thruster obtaining high performance. We derive two mission pro les one for fusion pulse propulsion, and the yet hypothetical Q-Thruster. Fusion thruster requires 132.2 years for Tau Ceti, and 233.2 years for Gliese 667C, while Q-Thruster takes only 42.3 years for Tau Ceti, and 62.5 years for Gliese 667C. We also discuss extended roles for intelligent interstellar probes such as self-reproduction via nanotechnology, refueling, construction, robotic bodies, and transmission of brain simulations.
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Physical Sciences, Optics; OMAG method; flow rate measurement; micro flow rate
Online: 26 November 2018 (08:37:55 CET)
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Optical micro-angiography (OMAG) is a new method of detecting flow rate and widely used for in vivo imaging. Although OMAG can distinguish between flowing and stationary parts, it cannot obtain accurate flow rate information. This study proposed a range formula for OMAG and the ultrahigh-sensitivity OMAG (UHS-OMAG) method to quantify the measurement range of an entire system. The parameters of the angle between beam scanning and flow directions, the angular velocity of the galvanometer, and the offset of incident light were introduced, and a formula for calculating the range was derived. Experiments were conducted to measure fine and ultra-fine flow rates by using OMAG and UHS-OMAG methods. The minimum measured flow rate was approximately 30 μm/s, and the maximum measured flow rate was approximately 8 mm/s. Experimental results are in good agreement with the preset results.
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Physical Sciences, General & Theoretical Physics; Maxwell's demon; Shannon entropy; information engine; Landauer's principle; Szilard engine; second law of thermodynamics
Online: 26 November 2018 (05:27:27 CET)
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We introduce and investigate a simple and explicitly mechanical model of Maxwell's demon -- a device that interacts with a memory register (a stream of bits), a thermal reservoir (an ideal gas) and a work reservoir (a mass that can be lifted or lowered). Our device is similar to one that we have briefly described elsewhere [1], but it has the additional feature that it can be programmed to recognize a chosen reference sequence, for instance, the binary representation of $\pi$. If the bits in the memory register match those of the reference sequence, then the device extracts heat from the thermal reservoir and converts it into work to lift a small mass. Conversely, the device can operate as a generalized Landauer's eraser (or copier), harnessing the energy of a dropping mass to write the chosen reference sequence onto the memory register, replacing whatever information may previously have been stored there. Our model can be interpreted either as a machine that autonomously performs a conversion between information and energy, or else as a feedback-controlled device that is operated by an external agent. We derive generalized second laws of thermodynamics for both pictures. We illustrate our model with numerical simulations, as well as analytical calculations in a particular, exactly solvable limit.
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Physical Sciences, Astronomy & Astrophysics; Gravitational atom; quantum black hole; quantum levels; Schrodinger equation; mass spectrum.
Online: 23 November 2018 (14:29:57 CET)
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We apply Rosen’s approach to the quantization of the gravitational collapse in the simple case of a pressureless “star of dust” and we find the gravitational potential, the Schroedinger equation and the solution for the collapse’s energy levels without any approximation. By applying the constrains for a black hole (BH), we found the analogous quantum quantities and the BH mass spectrum, again without any approximation. Remarkably, such a mass spectrum is the same which was found by Beken-
stein in 1974. Finally, our approach permits to find the exact quantum representation of the Schwarzschild BH ground state at the Planck scale.
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Physical Sciences, Particle & Field Physics; nonperturbative quantum gravity; regge-wheeler lattice path integral formulation; gravitational vacuum condensate
Online: 23 November 2018 (02:56:27 CET)
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In quantum gravity perturbation theory in Newton's constant $G$ is known to be badly divergent, and as a result not very useful. Nevertheless, some of the most interesting phenomena in physics are often associated with non-analytic behavior in the coupling constant and the existence of nontrivial quantum condensates. It is therefore possible that pathologies encountered in the case of gravity are more likely the result of inadequate analytical treatment, and not necessarily a reflection of some intrinsic insurmountable problem. The nonperturbative treatment of quantum gravity via the Regge-Wheeler lattice path integral formulation reveals the existence of a new phase involving a nontrivial gravitational vacuum condensate, and a new set of scaling exponents characterizing both the running of $G$ and the long-distance behavior of invariant correlation functions. The appearance of such a gravitational condensate is viewed as analogous to the (equally nonperturbative) gluon and chiral condensates known to describe the physical vacuum of QCD. The resulting quantum theory of gravity is highly constrained, and its physical predictions are found to depend only on one adjustable parameter, a genuinely nonperturbative scale $\xi$ in many ways analogous to the scaling violation parameter $\Lambda_{\bar MS} $ of QCD. Recent results point to significant deviations from classical gravity on distance scales approaching the effective infrared cutoff set by the observed cosmological constant. Such subtle quantum effects are expected to be initially small on current cosmological scales, but could become detectable in future high precision satellite experiments.
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Physical Sciences, Condensed Matter Physics; Voronoi entropy; surface patterns; Lewis law; Aboav law; droplet cluster; self-assembly
Online: 22 November 2018 (04:49:13 CET)
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The Voronoi entropy is a mathematical tool for quantitative characterization of the orderliness of points distributed on a surface. The tool is useful to study various surface self-assembly processes. We provide the historical background, from Kepler and Descartes to our days, and discuss topological properties of the Voronoi tessellation, upon which the entropy concept is based, and its scaling properties, known as the Lewis and Aboav-Weaire laws. The Voronoi entropy has been successfully applied to recently discovered self-assembled structures, such as patterned micro-porous polymer surfaces obtained by the breath figure method and levitating ordered water micro-droplet clusters.
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Physical Sciences, Applied Physics; Dancing, Muscle stretching exercise, Pliability
Online: 21 November 2018 (13:29:32 CET)
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Objective: The purpose of this study is to compare the effects of stretching methods for flexibility, muscle activation, and pressure pain threshold in ballet dancers, and to suggest an effective stretching method. Methods: Thirty-three ballet dancers were randomized to a static stretching group (n=11), muscle energy technique stretching group (n=11), and vibration-assisted stretching group (n=11). The angle of hip joint extension in arabesque, the activation of rectus femoris in Devéloppé, and the pressure pain threshold on rectus femoris in sitting position were measured to compare the effects of different stretching methods. Results: Hip joint extension angles increased in all stretching methods (p<0.05), however, vibration-assisted stretching and muscle energy technique stretching were more effective than static stretching (p<0.05). The activation of the rectus femoris decreased in all groups (p<0.05), but the muscle energy technique stretching group and the vibration-assisted stretching group showed a significant decrease compared to the static stretching group (p<0.05). The pressure pain threshold showed significant improvement only in the static stretching group (p<0.05), and the vibration-assisted stretching group (p<0.05). Conclusion: Vibration-assisted stretching compared to static stretching and muscle energy technique stretching is a beneficial method for flexibility, muscle activation, and pressure pain threshold in ballet dancers.
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Physical Sciences, Applied Physics; characterization; thermal radiation
Online: 21 November 2018 (11:27:40 CET)
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The study sought to determine solar irradiation in Homa Bay County which can be tapped and utilized in improving lives of residents of the region by converting the solar thermal energy in Home Bay to other forms of energy such as electric form, mechanical form and light. The study was done by assessing the local atmospheric conditions which included sunshine duration data and air temperature records for the period of two years and the data obtained subjected to statistical analysis to determine the localized characteristics of the resource. The characteristics that were examined include; seasonal and annual power expectations as well as resource reliability. The solar irradiance of Home County was found to be 768.0 W/m2.
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Physical Sciences, Optics; printed electronics; inkjet printinh; terahertz time domain spectroscopy; vortex phase plate; vortex beam
Online: 21 November 2018 (07:36:26 CET)
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Printed electronic devices are attracting significant interest due to their versatility and low cost; however, quality control during manufacturing is a significant challenge preventing the widespread adoption of this promising technology. We show that terahertz radiation can be used for the in-situ inspection of printed electronic devices, as confirmed through a comparison with conventional electrical conductivity methods. Our in-situ method consists in printing a simple test pattern exhibiting a distinct signature in the THz range that enables the precise characterization of electrical conductivities of the printed ink. We demonstrate that contactless dual-wavelength THz spectroscopy analysis, which requires only a single THz measurement, is more precise and repeatable than the conventional four-point probe conductivity measurement method. Our results open the door to a simple strategy for performing contactless quality control in real time of printed electronic devices at any stage of its production line.
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Physical Sciences, Astronomy & Astrophysics; radio astronomy; interferometry; square kilometre array; big data; faraday tomography
Online: 21 November 2018 (07:19:33 CET)
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The Square Kilometre Array (SKA) will be both the largest radio telescope ever constructed and the largest Big Data project in the known Universe. The first phase of the project will generate on the order of 5 zettabytes of data per year. A critical task for the SKA will be its ability to process data for science, which will need to be conducted by science pipelines. Together with polarization data from the LOFAR Multifrequency Snapshot Sky Survey (MSSS), we have been developing a realistic SKA-like science pipeline that can handle the large data volumes generated by LOFAR at 150 MHz. The pipeline uses task-based parallelism to image, detect sources, and perform Faraday Tomography across the entire LOFAR sky. The project thereby provides a unique opportunity to contribute to the technological development of the SKA telescope, while simultaneously enabling cutting-edge scientific results. In this paper, we provide an update on current efforts to develop a science pipeline that can enable tight constraints on the magnetised large-scale structure of the Universe.
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Physical Sciences, Condensed Matter Physics; Niobium thin film; proximity effects; superconductivity; quantum confinement
Online: 20 November 2018 (16:24:34 CET)
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tructural and superconducting properties of high quality Niobium nanofilms with different thicknesses are investigated on silicon oxide and sapphire substrates. The role played by the different substrates and the superconducting properties of the Nb films are discussed based on the defectivity of the films and on the presence of an interfacial oxide layer between the Nb film and the substrate. The X-ray absorption spectroscopy is employed to uncover the structure of the interfacial layer. We show that this interfacial layer leads to a strong proximity effect, specially in films deposited on a SiO2 substrate, altering the superconducting properties of the Nb films. Our results establish that the critical temperature is determined by an interplay between quantum-size effects, due to the reduction of the Nb film thicknesses, and proximity effects.
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Physical Sciences, General & Theoretical Physics; statistical physics; special relativity; arrow of time
Online: 20 November 2018 (12:10:26 CET)
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Consistent with special relativity and statistical physics, here we construct a partition function of space-time events. The union of these two theories resolves longstanding problems regarding time. We will argue that it augments the standard description of time given by the (non-relativistic) arrow of time to one able to describe the past, the present and the future in a manner consistent with our macroscopic experience of such. First, using Fermi-Dirac statistics, we find that the system essentially describes a "waterfall" of space-time events. This "waterfall" recedes in space-time at the speed of light towards the direction of the future as it "floods" local space with events that it depletes from the past. In this union, an observer $\mathcal{O}$ will perceive two horizons that can be interpreted as hiding events behind them. The first is an event horizon and its entropy hides events in the regions that $\mathcal{O}$ cannot see. The second is a time horizon, and its entropy "shields" events from $\mathcal{O}$'s causal influence. As only past events are "shielded" and not future events, an asymmetry in time is thus created. Finally, future events are hidden by an entropy prohibiting $\mathcal{O}$ from knowing the future before the present catches on.
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Physical Sciences, Astronomy & Astrophysics; Quasi Steady State Cosmology, Radiation Phase
Online: 19 November 2018 (16:48:10 CET)
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Analytical solutions for radiation dominated phase of Quasi Steady State Cosmology in Friedmann-Robertson-Walkar models are obtained. We find that matter density is positive in all the cases (k = 0,-1,1). The nature of Hubble parameter (H) in [0,2] is discussed. The deceleration parameter (q) is marginally less than zero indicating accelerating universe. The scale factor (S) is graphically shown with time. The model represents oscillating universe between the above mentioned limits. Because of bounce in QSSC, the maximum density phase is still matter dominated. The models represent singularity free model. We also find that the models have event horizon i.e. no observer beyond the proper distance rH can communicate each other in FRW mdels for radiation dominated phase in the frame work of QSSC. The FRW models are special classes of Bianchi type I, V, IX space-times with zero, negative and positive curvatures respectively. Initially i.e. at = 0, the model represents steady model. We have tried to show how a good fit can be obtained to the observations in the framework of QSSC during radiation dominated phase.
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Physical Sciences, Optics; focusing schlieren; temperature; measurements
Online: 19 November 2018 (10:58:10 CET)
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In this work, we propose a method to measure planar temperature fields of fluids flow. We used a focusing schlieren technique together with a calibration procedure to fulfill such purpose. The focusing schlieren technique uses an off-axis circular illumination to reduce the depth of focus of the optical system. The calibration procedure is based on the relation of the intensity level of each pixel of a focused schlieren image to the corresponding cutoff grid position measured at the exit focal plane of the schlieren lens. The method is applied to measure planar temperature fields of the hot air issuing from a 10 mm diameter nozzle of a commercial Hot Air Gun Soldering Station Welding. Our tests are carried out at different temperature values and different planes along the radial position of the nozzle of the Hot Air Gun Soldering Station Welding. The temperature values obtained experimentally are in agreed with those obtained with a thermocouple.
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Physical Sciences, Fluids & Plasmas; entropy; thermodynamics; conservative hydrodynamics; rotations; meniscus; planets; negative pressure
Online: 19 November 2018 (09:42:08 CET)
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This is a review of efforts to discover action principles for Hydrodynamics and Thermodynamics. The work began with a determined attempt to create sources for Einstein's equations that describe continuous matter - as opposed to point particles. This requires a relativistic action principle. This report is mainly about (non relativistic) Adiabatic Thermodynamics, non equilibrium thermodynamics based on the method of Gibbs. The main relations of classical thermodynamics can be derived from an action principle, in the classical global form and in the local form advocated by Callen. The entropy is defined as the negative derivative of the free energy (free energy density) with respect to the volume (density). This is integrated with an action principle for hydrodynamics that was known to Lagrange in 1760. It is strongly limited to irrotational velocity fields, nevertheless it provides the needed Lagrangian for a large part of thermodynamics. This is the subject of the first 3 sections. It includes a brief review of a new theory of mixtures. The most difficult part of the program has been the discovery of Conservative Hydrodynamics with the required four independent degrees of freedom, with general flows. We give an account of the genesis and the structure of this theory, then a tour of recent applications.
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Kenichi Nishikawa,
Yosuke Mizuno,
Jose L. Gomez,
Ioana Dutan,
Athina Meli,
Jacek Niemiec,
Oleh Kobzar,
Martin Pohl,
Helene Sol,
Nicholas MacDonald,
Dieter H. Hartmann
Physical Sciences, Astronomy & Astrophysics; particle-in-cell simulations; relativistic jets; the Weibel instability; kink-like instability; mushroom instability; global jets; helical magnetic fields; recollimation shocks
Online: 16 November 2018 (05:12:40 CET)
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The Particle-In-Cell (PIC) method has been developed in order to investigate microscopic phenomena, and with the advances of computing power, newly developed codes have been used for several fields such as astrophysical, magnetospheric, and solar plasmas. Its applications have grown extensively with large computing powers available such as Pleiades and Blue Water systems in the US. For astrophysical plasmas research PIC method has been utilized in several topics such as reconnection, pulsar, non-relativistic shocks, relativistic shocks, relativistic jets, etc. As one of the research topics in astrophysics, PIC simulations of relativistic jets are reviewed up to the present time with the emphasis on the physics involved in the simulations. In this review we summarize PIC simulations starting with the Weibel instability in slab models of jets and then, continuing with recent progresses on global jets with helical magnetic fields including kinetic Kelvin-Helmholtz instabilities and mushroom instabilities.
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Gideon F. Steyn,
Lyndon S. Anthony,
Faical Azaiez,
Shadley Baard,
Robert A. Bark,
A. Hugo Barnard,
Philip Beukes,
Johan I. Broodryk,
J. Lowry Conradie,
John C. Cornell,
J. Garrett de Villiers,
Stuart G. Dolley,
Herman du Plessis,
William D. Duckitt,
Dirk T. Fourie,
Mike E. Hogan,
Ivan H. Kohler,
Kobus J. Lawrie,
Chris Lussi,
Joele P. Mira,
K. Vuyo Mjali,
Hendrik W. Mostert,
Clive Naidoo,
Fhumulani Nemulodi,
David Saal,
Nieldane P. Stodart,
Rainer W. Thomae,
Johan van Niekerk,
Pieter A. van Schalkwyk
Physical Sciences, Applied Physics; radionuclide production; target stations; targetry; 70 MeV cyclotron
Online: 16 November 2018 (04:01:41 CET)
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The development of new target stations for radioisotope production based on a dedicated 70~MeV commercial cyclotron is described. Currently known as the South African Isotope Facility (SAIF), this initiative will free the existing separated-sector cyclotron (SSC) at iThemba LABS (near Cape Town) to mainly pursue research activities in nuclear physics and radiobiology. It is foreseen that the completed SAIF facility will realize a three-fold increase in radioisotope production capacity compared to the current programme based on the SSC.
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Physical Sciences, Applied Physics; Bio-sensing, Extinction cross-section, Nano-particles, Plasmons, Raman scattering.
Online: 15 November 2018 (14:54:58 CET)
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In this paper, the far field and near field optical responses of a gold nanoparticle are studied and simulated numerically. The electromagnetic field was excited by an electric dipole located near one end of the nanorod, which is used to model the emission of a quantum dot. Another excitation method was also simulated in which an incident plane wave is used. The excitation of dark plasmon modes of the gold nanorod is presented. The Poynting equation was solved numerically to study the influence of the gold nanorod on the dipole radiative power. In addition, the extinction cross section of the gold nanoparticle illuminated by the incident plane wave was calculated to estimate the amount of the scattered and absorbed light.
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Physical Sciences, General & Theoretical Physics; stochastic thermodynamics, heat transfer, oscillators networks, entropy production
Online: 15 November 2018 (10:28:28 CET)
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We apply the stochastic thermodynamics formalism to describe the dynamics of systems of complex Langevin and Fokker-Planck equations. We provide in particular a simple and general recipe to calculate thermodynamical currents, dissipated and propagating heat for networks of nonlinear oscillators. By using the Hodge decomposition of thermodynamical forces and fluxes, we derive a formula for entropy production that generalises the notion of non-potential forces and makes transparent the breaking of detailed balance and of time reversal symmetry for states arbitrarily far from equilibrium. Our formalism is then applied to describe the off-equilibrium thermodynamics of a few examples, notably a continuum ferromagnet, a network of classical spin-oscillators and the Frenkel-Kontorova model of nano friction.
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Physical Sciences, Fluids & Plasmas; Landau damping; resonant transfer; anharmonic lattice; nonlinear waves; collective modes; gravity waves; Stokes flow; Basset drag force; surfactant approximation; fractional derivative; anharmonic
Online: 15 November 2018 (05:43:52 CET)
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The Landau damping effect was observed in collisionless plasma, as a microscopic resonant mechanism between electromagnetic radiation and the collective modes. In this paper we demonstrate the occurrence of the Landau damping at macroscopic scale in the interaction between water waves and anharmonic lattice of magnetic buoys. By coupling the Navier-Stokes equations for incompressible fluid with the nonlinear dynamics of an anharmonic magnetic lattice we obtain a resonant transfer of momentum and energy between the two systems. The velocity of the flow is obtained in the Stokes approximation with Basset type of drag force. The dynamics of the buoys is calculated in the surfactant approximation for a specific frequency, then we use Fourier analysis to obtain the general time variable interaction. After involving an integral Dirichlet transform we obtain the time dependent expression of the drag force, the interaction waves-lattice with a new term in the form of a Caputo fractional derivative. We compare the results of the model with experiments performed in a wave tank with free floating magnetic buoys under the action of small amplitude gravitational waves. This configuration can be applied in studies for the attenuation with resonant damping of rogue waves, storms or tsunamis.
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Physical Sciences, Applied Physics; liquid splashing; dimensional analysis; directed dimensional analysis
Online: 15 November 2018 (05:06:10 CET)
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This letter attempts to find splashing height of liquid-filled container drop impact to a solid surface by dimensional analysis (DA). Two solutions were obtained by both traditional DA and directed DA without solving any governing equations. It is found that the directed DA can provide much more useful information than the traditional one. This study shows that the central controlling parameter is called splash number $\mathrm{Sp}=\mathrm{Ga} \mathrm{La}^\beta=(\frac{gR^3}{\nu^2})(\frac{\sigma R}{\rho \nu^2})^\beta$, which is the collective performance of each quantity. The splash height is given by $ \frac{h}{H}=(\frac{\rho\nu^2}{\sigma R})^\alpha f[\frac{gR^3}{\nu^2}(\frac{R\sigma}{\rho\nu^2})^\beta]=\frac{1}{\mathrm{La}^\alpha}f(\mathrm{Ga}\cdot \mathrm{La}^\beta)$. From the physics of the splashing number, we can have a fair good picture on the physics of the liquid splashing as follows: the jets propagation will generate vortex streets from the container bottom due to sudden pressure increasing from drop impact (water-hammer effect), which will travel along the container sidewall to the centre of the container and subsequently excite a gravity wave on the liquid surface. The interaction between the gravitational force, surface force and viscous force is responsible for creating droplet splash at the liquid surface.
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Physical Sciences, Mathematical Physics; constrains; Maxwell theory; evolutionary equations
Online: 13 November 2018 (11:03:45 CET)
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The constraint equations in Maxwell theory are investigated. In analogy with some recent results on the constraints of general relativity it is shown, regardless of the signature and dimension of the ambient space, that the "divergence of a vector field" type constraints can always be put into linear first order hyperbolic form for which global existence and uniqueness of solutions to an initial-boundary value problem is guaranteed.
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Physical Sciences, General & Theoretical Physics; quasi-monochromatic waves; group velocity; dispersion relation; longitudinal modulation; coherence time
Online: 13 November 2018 (09:24:07 CET)
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The wave packet consisting of two harmonic plane waves with the same frequencies, but with different wave vectors is considered. The dispersion relation of a packet is structurally similar to the dispersion relation of a relativistic particle with a nonzero rest mass. The possibility of controlling the group velocity of a quasi-monochromatic wave packet by varying the angle between the wave vectors of its constituent waves is discussed.
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Physical Sciences, Condensed Matter Physics; q-states clock model; Entropy; Berezinskii-Kosterlitz-Thouless transition
Online: 13 November 2018 (05:09:16 CET)
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In this paper, we revisit the q-states clock model for small systems. We present results for the thermodynamics of the q-states clock model from $q=2$ to $q=20$ for small square lattices $L \times L$, with L ranging from $L=3$ to $L=64$ with free-boundary conditions. Energy, specific heat, entropy and magnetization are measured. We found that the Berezinskii-Kosterlitz-Thouless (BKT)-like transition appears for $q>5$ regardless of lattice size, while the transition at $q=5$ is lost for $L<10$; for $q\leq 4$ the BKT transition is never present. We report the phase diagram in terms of $q$ showing the transition from the ferromagnetic (FM) to the paramagnetic (PM) phases at a critical temperature T$_1$ for small systems which turns into a transition from the FM to the BKT phase for larger systems, while a second phase transition between the BKT and the PM phases occurs at T$_2$. We also show that the magnetic phases are well characterized by the two dimensional (2D) distribution of the magnetization values. We make use of this opportunity to do an information theory analysis of the time series obtained from the Monte Carlo simulations. In particular, we calculate the phenomenological mutability and diversity functions. Diversity characterizes the phase transitions, but the phases are less detectable as $q$ increases. Free boundary conditions are used to better mimic the reality of small systems (far from any thermodynamic limit). The role of size is discussed.
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Physical Sciences, Astronomy & Astrophysics; cosmological constant; MOND; dark matter; dark energy; Lamda-CDM model
Online: 12 November 2018 (08:39:24 CET)
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In this article it is shown how Milgrom’s acceleration constant is related with the ΩΛ, Ωm and ΩB values of the matter distribution within observable universe as defined in the Standard Model of Cosmology, established by the Planck Collaboration Group. The result is a two-parameter model for the observable universe. The two parameters are the age of the universe and Milgrom’s acceleration constant. It is shown that these are sufficient to calculate the amounts of matter and dark energy in the universe, as well as the contributions of dark matter and baryonic matter in the matter part. The numerical results are in agreement with those of the Lamda-CDM model.
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Physical Sciences, Astronomy & Astrophysics; perihelion; gravity
Online: 12 November 2018 (04:20:50 CET)
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We use oblate coordinates to study its resulting orbit equations. Their related solutions of Einstein's vacuum equations can be written as a linear combination of Legendre polynomials of positive de nite integers $l$. Starting from solutions of the zeroth order $l=0$ in a nearly newtonian regime, we obtain a non-trivial formula favoring both retrograde and advanced solutions for the apsidal precession depending on parameters related to the metric coecients, particularly applied to the apsidal precessions of Mercury and asteroids (Icarus and 2 Pallas). As a realization of the equivalence problem in general Relativity, a comparison is made with the resulting perihelion shift produced by Weyl cylindric coordinates and the Schwarzschild solution analyzing how diff erent geometries of space-time influence on solutions in astrophysical phenomena.
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Physical Sciences, Mathematical Physics; High-Throughput Molecular Dynamics (HTMD) simulations; Nosé-Hoover Chain (NHC); Canonical ensemble; Graphics Processing Units (GPUs).
Online: 9 November 2018 (15:26:49 CET)
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Molecular dynamics simulation is currently the theoretical technique eligible to simulate a wide range of systems from soft condensed matter to biological systems. However, of the excellent results that the technique has arrogated, this approach remains computationally expensive, but with the emergence of the new supercomputing technologies bases on graphics processing units graphical processing units-based systems GPUs, the perspective has changed. The GPUs allow performing large and complex simulations at a significantly reduced time. In this work, we present recent innovations in the acceleration of molecular dynamics in GPUs to simulate non-Hamiltonian systems. In particular, we show the performance of measure-preserving geometric integrator in the canonical ensemble, that is, at constant temperature. We provide a validation and performance evaluation of the code by calculating the thermodynamic properties of a Lennard-Jones fluid. Our results are in excellent agreement with reported data reported from literature, which were calculated with CPUs. The scope and limitations for performing simulations of high-throughput MD under rigorous statistical thermodynamics in the canonical ensemble are discussed and analyzed.
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Physical Sciences, Applied Physics; couple stress theory; size-dependent mechanics; indeterminacies; curvature tensor; torsion tensor
Online: 9 November 2018 (04:01:56 CET)
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In this paper, we examine the mathematical and physical consistencies of the three primary couple stress theories: original Mindlin-Tiersten-Koiter couple stress theory (MTK-CST), modified couple stress theory (M-CST) and consistent couple stress theory (C-CST). As has been known for many years, MTK-CST suffers from some fundamental inconsistencies, such as the indeterminacy of the couple-stress tensor. Therefore, despite the fact that MTK-CST has a fundamental position in the evolution of size-dependent continuum mechanics, it is not a reliable theory within continuum mechanics, for example, in developing new size-dependent multi-physics formulations. We also observe that M-CST not only inherits all inconsistences from the original MTK-CST, but also suffers from new additional inconsistencies, such as the introduction of a new non-physical governing equation. These inconsistencies refute the claim of those who state that the couple-stress tensor may be chosen symmetric. Therefore, the apparent success of MTK-CST and M-CST in describing a size-effect for some problems, such as two-dimensional plate and beam bending, is not enough to justify these theories as suitable for general cases. In fact, the symmetric couple-stresses in M-CST create torsional or anticlastic deformation, not bending. On the other hand, C-CST, with a skew-symmetric couple-stress tensor, is the consistent continuum mechanics suitable for solving different size-dependent solid, fluid and multi-physics problems.
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Physical Sciences, Condensed Matter Physics; entropy generation; entropy acceleration; glucose catabolism; irreversible reactions; heat transfer; matter transfer; cancer biology; stem cell biology
Online: 9 November 2018 (03:49:41 CET)
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The heat and matter transfer during glucose catabolism in living systems and their relation with entropy production are a challenging subject of the classical thermodynamics applied to biology. In this respect, an analogy between mechanics and thermodynamics has been performed via the definition of the entropy density acceleration expressed by the time derivative of the rate of entropy density and related to heat and matter transfer in minimum living systems. Cells are regarded as open thermodynamic systems that exchange heat and matter resulting from irreversible processes with the intercellular environment. Prigogine’s minimum energy dissipation principle is reformulated using the notion of entropy density acceleration applied to glucose catabolism. It is shown that, for out-of-equilibrium states, the calculated entropy density acceleration is finite and negative and approaches as a function of time a zero value at global thermodynamic equilibrium for heat and matter transfer independently of the cell type and the metabolic pathway. These results could be important for a deeper understanding of entropy generation and its correlation with heat transfer in cell biology with special regard to glucose catabolism representing the prototype of irreversible reactions and a crucial metabolic pathway in stem cells and cancer stem cells.
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Physical Sciences, Condensed Matter Physics; multi-scale modeling; lubrication; viscous heating; entangled polymeric liquid
Online: 8 November 2018 (15:00:16 CET)
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The thermal lubrication of an entangled polymeric liquid in wall-driven shear flows between parallel plates is investigated by using a multiscale hybrid method coupling molecular dynamics and the hydrodynamics (i.e., the synchronized molecular dynamics method).
The temperature of the polymeric liquid rapidly increases due to viscous heating once the drive force exceeds a certain threshold value.
The rheological properties of the polymeric liquid drastically change at around the critical drive force.
In the weak viscous-heating regime, the conformation of polymer chains is dominated by the local shear flow so that the anisotropy of the bond orientation tensor grows as the drive force increases.
However, in the large viscous-heating regime, the conformation dynamics is dominated by the thermal agitation of polymer chains so that the bond orientation tensor recovers more uniform and random structures as the drive force increases, even though the local shear flows are further enhanced.
Remarkably, these counter-intuitive transitional behaviors give an interesting re-entrant transition in the stress--optical relation, where a linear formalism in the stress--optical relation approximately holds even though each of the macroscopic quantities behaves nonlinearly.
The robustness of the linear stress--optical relation is also confirmed in the spatiotemporal evolution at the hydrodynamic level.
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Physical Sciences, Condensed Matter Physics; Electrochemical polymerization; Poly-9,10-phenanthrenequinone; Modified electrode; Conducting polymers; Redox polymers; Electrochemical impedance spectroscopy
Online: 8 November 2018 (14:38:05 CET)
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A 9,10-phenanthrenequinone (PQ) was electrochemically polymerized on a graphite rod electrode using potential cycling. The electrode modified by poly-9,10-phenanthrenequinone (poly-PQ) was studied by means of cyclic voltammetry, electrochemical impedance spectroscopy, atomic force microscopy and scanning electron microscopy. The poly-PQ shows variations in growth pattern depending on the number of potential cycles for the initiation of polymerization. Formed poly-PQ layer demonstrates good electric conductivity, great electrochemical capacitance and unique oxidation/reduction properties, which are suitable for broad technological applications, including applicability in biosensors, supercapacitors, and in some other electrochemical systems.
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Oleg Malkov,
Sergey Karpov,
Dana Kovaleva,
Sergey Sichevsky,
Dmitry Chulkov,
Olga Dluzhnevskaya,
Alexey Kniazev,
Areg Mickaelian,
Alexey Mironov,
Jayant Murthy,
Alexey Sytov,
Gang Zhao,
Aleksandr Zhukov
Physical Sciences, Astronomy & Astrophysics; parallax; photometry; interstellar extinction; surveys; Gaia
Online: 8 November 2018 (11:08:30 CET)
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We present the result of comparison of Gaia DR2 parallaxes and photometry with data derived from a combined analysis of 2MASS, SDSS, GALEX, and UKIDSS surveys in four selected high-latitude sky areas. We have shown that, under certain circumstances, multicolor photometric data from large modern surveys can be successfully used for parameterization of stars, including estimation of distance and interstellar extinction value.
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Physical Sciences, Astronomy & Astrophysics; Cosmic Rays; Massive Star Supernovae; Cosmic Ray Knee and Ankle.
Online: 8 November 2018 (09:53:33 CET)
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We propose that the high energy Cosmic Ray particles around the spectral turn-down commonly called the {\it knee} and up to the upturn, commonly called the {\it ankle}, mostly come from Blue Super Giant star explosions. At the upturn, i.e. the {\it ankle}, Cosmic Rays probably switch to another source class, most likely extragalactic sources. To show this we recently compiled a set of Radio Supernova data to list the magnetic field, shock speed and radius scale (Biermann et al. 2018) \cite{Biermann18}. Using particle acceleration theory at shocks, those numbers can be transformed into characteristic {\it knee} and {\it ankle} energies. Without adjusting any free parameters both of these observed energies are directly indicated by the supernova data. We now proceed to the next step in the argument, and use the Supernova Remnant data of the starburst galaxy M82. Assuming that they are Blue Supergiant star explosions, the shock will race to their outer edge with a magnetic field that follows ${B (r) \, r \, \sim \, const.}$. We argue that the shock runs through the entire magnetic plasma wind region at full speed all the way out to the wind-shell, which is of order parsec scale. The speed is observed to be $\sim \, 0.1 \, c$ at about ${10^{16} \, {\rm cm}}$ radius in the plasma wind. This demonstrates how Blue Supergiant star explosions can provide the Cosmic Ray particles across the {\it knee} and up to the {\it ankle} energy range. The data from the CREAM (Cosmic Ray Energetics and Mass Experiment) mission will test this cosmic ray concept which is reasonably well grounded in two independent radio supernova data sets. The next step in developing our understanding is to obtain accurate Cosmic Ray data near to the {\it knee}, and use unstable isotopes of Cosmic Ray nuclei at high energy to probe the "piston" driving the explosion. We plan to combine these data with the physics of the budding black hole which is probably forming in each of these stars to learn more.
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Physical Sciences, General & Theoretical Physics; measure of time; entropy; laws of motion; repulsive and attractive forces.
Online: 7 November 2018 (14:41:05 CET)
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An idea expressed in the paper [Entropy 2017, 19, 345] about the deductive formulation of a physical theory resting on explicitly- and universally-introduced basic concepts is developed. An entropic measure of time with a number of properties leading to an analog of the Galilei–Einstein relativity principle is considered. Using the introduced measure and a simple model, a kinematic law relating the size, time, and number of particles of a system is obtained. Corollaries of this law are examined. In particular, accelerated increase of the system size and, if the system size remains unchanged, decrease of the number of particles are found. An interesting corollary is the emergence of repulsive and attractive forces inversely proportional to the square of the system size for relatively dense systems and constant for sufficiently rarefied systems.
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Physical Sciences, Condensed Matter Physics; superconductivity; persistent currents; Joule effect; second law of thermodynamics
Online: 5 November 2018 (14:53:59 CET)
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A classical model is presented for persistent currents in superconductors. Their existence is argued to be warranted because their decay would violate the second law of thermodynamics. This conclusion is achieved by analyzing comparatively Ohm's law and the Joule effect in normal metals and superconducting materials. Whereas Ohm's law applies in identical terms in both cases, the Joule effect is shown to cause the temperature of a superconducting sample to \textit{decrease}. An experiment is proposed to check the validity of this work in superconductors of both types I and II.
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Physical Sciences, Particle & Field Physics; time reversal; retro-causality; fermi golden rule; perturbation theory
Online: 5 November 2018 (10:25:26 CET)
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Quantum effects arising from manifestly broken time-reversal symmetry are investigated using time-dependent perturbation theory in a simple model. The forward time and the backward time Hamiltonians are taken to be different and hence the forward and backward amplitudes become unsymmetrical and are not complex conjugates of each other. The effects vanish when the symmetry breaking term is absent and ordinary quantum mechanical results such as Fermi Golden rule are recovered.
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Physical Sciences, Astronomy & Astrophysics; galaxies; clusters; general—cosmology; theory—darkmatter—large-scale structure of universe
Online: 5 November 2018 (03:43:57 CET)
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According to the standard cold dark matter (CDM) cosmology, the structure of dark halos including those of galaxy clusters reflects their mass accretion history. Older clusters tend to be more concentrated than younger clusters. Their structure, represented by the characteristic radius $r_s$ and mass $M_s$ of the Navarro-Frenk-White (NFW) density profile, is related to their formation time. In this study, we show that $r_s$, $M_s$, and the X-ray temperature of the intracluster medium (ICM), $T_X$, form a thin plane in the space of $(\log r_s, \log M_s, \log T_X)$. This tight correlation indicates that the ICM temperature is also determined by the formation time of individual clusters. Numerical simulations show that clusters move along the fundamental plane as they evolve. The plane and the cluster evolution within the plane can be explained by a similarity solution of structure formation of the universe. The angle of the plane shows that clusters have not achieved “virial equilibrium” in the sense that mass/size growth and pressure at the boundaries cannot be ignored. The distribution of clusters on the plane is related to the intrinsic scatter in the halo concentration--mass relation, which is originated from the variety of cluster ages. The well-known mass--temperature relation of clusters ($M_\Delta\propto T_X^{3/2}$) can be explained by the fundamental plane and the mass dependence of the halo concentration without the assumption of virial equilibrium. The fundamental plane can also be used for calibration of cluster masses.
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Physical Sciences, Applied Physics; interpersonal coordination; competition; dynamical systems; discrete dynamics; continuous dynamics; sporting activity
Online: 5 November 2018 (03:30:07 CET)
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Complex human behavior, including interlimb and interpersonal coordination, has been studied from a dynamical system perspective. We review the applications of a dynamical system approach to a sporting activity, which includes continuous, discrete, and switching dynamics. Continuous dynamics identified switching between in- and anti-phase synchronization, controlled by an interpersonal distance of 0.1 m during expert kendo matches, using a relative phase analysis. As discrete dynamics, return map analysis was applied to the time series of movements during kendo matches, and six coordination patterns were classified. Furthermore, state transition probabilities were calculated based on the two states, which clarified the coordination patterns and switching behavior. We introduced switching dynamics with temporal inputs to clarify the simple rules underlying the complex behavior corresponding to switching inputs in a striking action as a non-autonomous system. As a result, we determined that the time evolution of the striking action was characterized as fractal-like movement patterns generated by a simple Cantor set rule with rotation. Finally, we propose a switching hybrid dynamics to understand both court-net sports, as strongly coupled interpersonal competition, and weakly coupled sports, such as martial arts.
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Physical Sciences, Atomic & Molecular Physics; precision measurements; fundamental constants; variation of constants; proton-to-electron mass ratio; molecular ions; forbidden transition; two-photon transition; vibrational overtone
Online: 2 November 2018 (12:58:06 CET)
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Vibrational overtones in deeply bound molecules are sensitive probes for variation of the proton-to-electron mass ratio μ. In nonpolar molecules, these overtones may be driven as two-photon transitions. Here, we present procedures for experiments with O2+, including state-preparation through photoionization, a two-photon probe, and detection. We calculate transition dipole moments between all X2Пg vibrational levels and those of the A2Пu excited electronic state. Using these dipole moments, we calculate two-photon transition rates and AC-Stark-shift systematics for the overtones. We estimate other systematic effects and statistical precision. Two-photon vibrational transitions in O2+ provide multiple routes to improved searches for μ variation.
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Physical Sciences, Astronomy & Astrophysics; Schwarzschild radius; maximum velocity of matter; probabilistic Schwarzschild radius; quasars; time dilation
Online: 2 November 2018 (11:11:47 CET)
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This is a short note on a new way to describe Haug's newly introduced maximum velocity for matter in relation to the Schwarzschild radius. This leads to a probabilistic Schwarzschild radius for elementary particles with mass smaller than the Planck mass. In addition, our maximum velocity, when linked to the Schwarzschild radius, seems to predict that particles just at that radius cannot move. This implies that radiation from the Schwarzschild radius not can undergo velocity time dilation. Our maximum velocity of matter, therefore, seems to predict no time dilation, even in high Z quasars, as has surprisingly been observed recently.
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Physical Sciences, General & Theoretical Physics; fermions; bosons; statistical complexity; entropy; disequilibrium
Online: 2 November 2018 (07:24:54 CET)
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We investigate the physics of a medium-size quantum particle' gases, of the order of hundreds or thousands of fermions/bosons (far below the thermodynamic limit $N \, \rightarrow \, 10^{24}$). Appeal to microcanonical ensemble becomes then unavoidable. The so-called statistical complexity is our protagonist. Interesting facts are uncovered, both for fermions and bosons, yielded by statistical quantifiers.
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Physical Sciences, Astronomy & Astrophysics; active galactic nuclei; radio galaxies; gamma-rays; jets
Online: 2 November 2018 (07:07:11 CET)
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Over the past decade, our knowledge of the $\gamma$-ray sky has been revolutionized by ground- and space-based observatories by detecting photons up to several hundreds of tera-electron volt (TeV) energies. A major population of the $\gamma$-ray bright objects are active galactic nuclei (AGN) with their relativistic jets pointed along our line-of-sight. Gamma-ray emission is also detected from nearby mis-aligned AGN such as radio galaxies. While the TeV-detected radio galaxies ($TeVRad$) only form a small fraction of the $\gamma$-ray detected AGN, their multi-wavelength study offers a unique opportunity to probe and pinpoint the high-energy emission processes and sites. Even in the absence of substantial Doppler beaming $TeVRad$ are extremely bright objects in the TeV sky (luminosities detected up to $10^{45}~erg~s^{-1}$), and exhibit flux variations on timescales shorter than the event-horizon scales (flux doubling timescale less than 5 minutes). Thanks to the recent advancement in the imaging capabilities of high-resolution radio interferometry (millimeter very long baseline interferometry, mm-VLBI), one can probe the scales down to less than 10 gravitational radii in $TeVRad$, making it possible not only to test jet launching models but also to pinpoint the high-energy emission sites and to unravel the emission mechanisms. This review provides an overview of the high-energy observations of $TeVRad$ with a focus on the emitting sites and radiation processes. Some recent approaches in simulations are also sketched. Observations by the near-future facilities like Cherenkov Telescope Array, short millimeter-VLBI, and high-energy polarimetry instruments will be crucial for discriminating the competing high-energy emission models.
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Physical Sciences, Optics; forecasting; complex dynamics; fiber laser; chaos; ordinal patterns
Online: 2 November 2018 (04:21:25 CET)
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Being able to forecast events is of great importance in many fields, from brain behavior to earthquakes or stock markets. Because each dynamical system has intrinsic features, different statistical tools have to be used for each system. Here we study the time series of the output intensity of a fiber laser with an ordinal patterns analysis, and we look for temporal correlations in order to statistically forecast the most intense events. We set two thresholds, a low one and a high one, to distinguish between low intensity versus high intensity events. We find that when the time series is performing events below the low threshold it shows some preferred temporal patterns before performing events above a high threshold.
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Physical Sciences, Astronomy & Astrophysics; Planck scale; Mach’s relation; quantum cosmology; critical density; ordinary matter; dark matter; thermal redshift; expansion velocity; rotational kinetic energy; dark energy; Hubble’s law
Online: 2 November 2018 (02:30:57 CET)
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With reference to Planck scale, Mach's relation and by introducing two new parameters Gamma and Beta, right from the beginning of Planck scale, we make an attempt to estimate ordinary matter density ratio, dark matter density ratio, mass, radius, temperature, age and expansion velocity (from and about the Planck mass in all directions). In analogy with currently believed cosmic acceleration, with a decreasing trend of total matter density ratio, cosmic expansion velocity can be shown to be increasing. By considering km/sec/Mpc, estimated current cosmic mass, radius, total matter density, expansion velocity, temperature and age are: and respectively. Point to be noted is that, with reference to Planck scale, cosmic temperature seems to be redshifted by a factor where represent Planck scale and time dependent Hubble parameters respectively. As a peculiar case, considering the equality of current Hubble parameter and current angular velocity, current cosmic rotational kinetic energy can be estimated to be 0.667 times the current critical energy. It needs further study.
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Physical Sciences, Astronomy & Astrophysics; Techniques: radio polarization; ISM: turbulence; ISM: magnetic fields
Online: 30 October 2018 (14:31:00 CET)
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Modern radio spectrometers make measurement of polarized intensity as a function of Faraday depth possible. I investigate the effect of depolarization along a model line of sight. I model sightlines with two components informed by observations: a diffuse interstellar medium with a lognormal electron density distribution and a narrow, denser component simulating a spiral arm or H~{\sc ii} region, all with synchrotron-emitting gas mixed in. I then calculate the polarized intensity from 300-1800 MHz and calculate the resulting Faraday depth spectrum. The idealized synthetic observations show far more Faraday complexity than is observed in Global Magneto-Ionic Medium Survey observations. In a model with a very nearby H~{\sc ii} region observed at low frequencies, most of the effects of a ``depolarization wall'' are evident: the H~{\sc ii} region depolarizes background emission and less (but not zero) information from beyond the H~{\sc ii} region reaches the observer. In other cases, the effects are not so clear, as significant amounts of information reach the observer even through significant depolarization, and it is not clear that low-frequency observations sample largely different volumes of the interstellar medium than high-frequency observations. The observed Faraday depth can be randomized such that it does not always have any correlation with the true Faraday depth.
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Physical Sciences, Astronomy & Astrophysics; cosmology; Bianchi Type I; particle creation; open thermodynamic system; constant deceleration parameter; accelerated expansion; late time acceleration
Online: 30 October 2018 (09:36:05 CET)
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A study of Bianchi Type I cosmological model is undertaken in the framework of creation of particles. To accommodate the creation of new particles, the universe is regarded as an Open thermodynamical system. The energy conservation equation is modified with the incorporation of a creation pressure in the energy momentum tensor. Exact solutions of the field equations are obtained (i) for a particular choice of the particle creation function and (ii) by considering the deceleration parameter to be constant. In the first model the behavior of the solution at late times is investigated. The physical aspects of the model have also been discussed. In the case of the second model we have restricted our analysis to the power law behaviour for the average scale factor. This leads to a particular form for the particle creation function. The behavior of the solution is investigated and the physical aspects of the model have also been discussed for the matter dominated era.
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Physical Sciences, Particle & Field Physics; nonequilibrium thermo field dynamics; kinetics; hydrodynamics; kinetic equations; transport coefficients; coupled states; quark-gluon plasma
Online: 30 October 2018 (04:52:07 CET)
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A formulation of nonequilibrium thermo field dynamics has been performed using the nonequilibrium statistical operator method by D.N. Zubarev. Generalized transfer equations for a consistent description of kinetics and hydrodynamics of the dense quantum-field system with strongly coupled states are derived.
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Physical Sciences, Atomic & Molecular Physics; zero-degree Auger projectile spectroscopy; mixed-state beams; metastable states; He-like states; Li-like states; Be-like states; cascade feeding; electron transfer excitation; electron excitation; electron transfer; hollow states; SIMION
Online: 30 October 2018 (03:53:32 CET)
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The use of mixed-state ionic beams in collision dynamics investigations is examined. Using high resolution Auger projectile spectroscopy involving He-like ($1s^2\thinspace^1\!S, 1s2s\thinspace^{3,1}\!S$) mixed-state beams, the spectrum contributions of the $1s2s\thinspace^3\!S$ metastable beam component is effectively separated and clearly identified. This is performed with a technique that exploits two independent spectrum measurements under the same collision conditions, but with ions having quite different metastable fractions, judiciously selected by varying the ion beam charge-stripping conditions. Details of the technique are presented together with characteristic examples. In collisions of 4 MeV B$^{3+}$ with H$_2$ targets, the Auger electron spectrum of the separated $1s2s\thinspace^{3}S$ boron beam component allows for a detailed analysis of the formation of the $1s2s(^3\!S)nl \thinspace^2\!L$ states by direct $nl$ transfer. In addition, the production of hollow $2s2p\thinspace^{1,3}\!P$ doubly- and $2s2p^2\thinspace^2\!D$ triply-excited states, by direct excitation and transfer-excitation processes, respectively, can also be independently studied. In similar mixed-state beam collisions of 15 MeV C$^{4+}$ with H$_2$, He, Ne and Ar targets, the contributions of the $1s^2$, $1s2s\thinspace^{3,1}S$ beam components to the formation of the $2s2p\thinspace^{3,1}\!P$ states by double-excitation, $1s\rightarrow2p$ excitation and transfer-loss processes can be clearly identified, facilitating comparisons with theoretical calculations.
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Physical Sciences, Applied Physics; seismic forecasting; foreshocks; stochastic model
Online: 29 October 2018 (11:47:36 CET)
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An increase of seismic activity is often observed before large earthquakes. Events responsible for this increase are usually named foreshock and their occurrence probably represents the most reliable precursory pattern. Many foreshocks statistical features can be interpreted in terms of the standard mainshock-to-aftershock triggering process and are recovered in the Epidemic Type Aftershock Sequence ETAS model. Here we present a statistical study of instrumental seismic catalogs from four different geographic regions. We focus on some common features of foreshocks in the four catalogs which cannot be reproduced by the ETAS model. In particular we find in instrumental catalogs a significantly larger number of foreshocks than the one predicted by the ETAS model. We show that this foreshock excess cannot be attributed to catalog incompleteness. We therefore propose a generalized formulation of the ETAS model, the ETAFS model, which explicitly includes foreshock occurrence. Statistical features of aftershocks and foreshocks in the ETAFS model are in very good agreement with instrumental results.
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Physical Sciences, General & Theoretical Physics; extended space-time; complex space-time; uni ed theories; geometric uni cation; dark matter-energy; Cartan's principle of triality;extended general-special relativity
Online: 29 October 2018 (11:32:19 CET)
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We explore the possibility to form a physical theory in C4. We argue that the expansion of our usual 4-d real space-time to a 4-d complex space-time, can serve us to describe geometrically electromagnetism and unify it with gravity, in a different way that Kaluza-Klein theories do. Speci cally, the electromagnetic eld Aμ, is included in the free geodesic equation of C4. By embedding our usual 4-d real space-time in the symplectic 8-d real space-time (symplectic R8 is algebraically isomorphic to C4), we derive the usual geodesic equation of a charged particle in gravitational eld, plus new information which is interpreted. Afterwards, we explore the consequences of the formulation of a "special relativity" in the at R8.
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Physical Sciences, Astronomy & Astrophysics; pierre auger observatory; ultra high energy cosmic rays; extensive air showers
Online: 29 October 2018 (05:29:29 CET)
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The Pierre Auger Observatory is the world's largest operating detection system for the observation of ultra high energy cosmic rays (UHECRs). The detector allows detailed measurements of their energy spectrum, mass composition and arrival directions of primary cosmic rays in the energy range above $10^{17}$ eV. The data collected at the Observatory over the last decade show the suppression of the cosmic ray flux at energies above $4\times10^{19}$ eV. However, it is still unclear if this suppression is caused by the propagation of cosmic rays or rather by energy limitation of their sources. The other puzzle is the origin of UHECRs. Some clues can be drawn from studying the distribution of their arrival directions. The recently observed dipole anisotropy has an orientation which indicates an extragalactic origin of UHECRs. The Auger surface detector array is also sensitive to showers due to ultra high energy neutrinos of all flavours and photons, and recent neutrino and photon limits provided by the Observatory can constrain models of the cosmogenic neutrino production and exotic scenarios of the UHECRs origin, such as the decays of super heavy particles. In this paper the recent results on measurements of the energy spectrum, mass composition and arrival directions of cosmic rays, and future prospects are presented.
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Physical Sciences, Astronomy & Astrophysics; magnetic fields; Faraday tomography; large-scale structure; AGN; Milky Way
Online: 26 October 2018 (15:35:41 CEST)
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The technique of Faraday tomography is a key tool for the study of magnetised plasmas in the new era of broadband radio polarisation observations. In particular, observations at metre-wavelengths provide significantly better Faraday depth accuracies compared to traditional cm-wavelength observations. However, the effect of Faraday depolarisation makes the polarised signal very challenging to detect at metre wavelengths (MHz frequencies). In this work, Faraday tomography is used to characterise the Faraday rotation properties of polarised sources found in data from the LOFAR Two-Metre Sky Survey (LoTSS). Of the 76 extragalactic polarised sources analysed here, we find that all host a radio-loud AGN. The majority of the sources (∼64%) are large FRII radio galaxies with a median projected linear size of 710 kpc and median radio luminosity at 144 MHz of 4 × 10^26 W/Hz. In several cases, both hotspots are detected in polarisation at an angular resolution of ∼20". One such case allowed a study of intergalactic magnetic fields on scales of 3.4 Mpc. Other detected source types include an FRI radio galaxy and at least 8 blazars. Most sources display simple Faraday spectra, however, we highlight one blazar that displays a complex Faraday spectrum, with two close peaks in the Faraday dispersion function.
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Physical Sciences, Condensed Matter Physics; crumpling transition; graphene; graphene-based polymers; crumples; parallel tempering; Monte Carlo; statistical mechanics
Online: 26 October 2018 (10:48:07 CEST)
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We numerically study surface models defined on hexagonal disks with a free boundary. 2D surface models for planer surfaces have recently attracted interest due to the engineering applications of functional materials such as graphene and its composite with polymers. These 2D composite meta-materials are strongly influenced by external stimuli such as thermal fluctuations if they are sufficiently thin. For this reason, it is very interesting to study the shape stability/instability of thin 2D materials against thermal fluctuations. In this paper, we study three types of surface models including Landau-Ginzburg (LG) and Helfirch-Polyakov models defined on triangulated hexagonal disks using the parallel tempering Monte Carlo simulation technique. We find that the planer surfaces undergo a first-order transition between the smooth and crumpled phases in the LG model and continuous transitions in the other two models. The first-order transition is relatively weaker compared to the transition on spherical surfaces already reported. The continuous nature of the transition is consistent with the reported results, although the transitions are stronger than that of the reported ones.
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Physical Sciences, General & Theoretical Physics; conformal invariance; brane world models; U(1) scalar-gauge field; dilaton field
Online: 26 October 2018 (10:33:55 CEST)
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We show that the Einstein field equations for a five-dimensional warped spacetime, where only gravity can propagate into the bulk, determine the dynamical evolution of the warp factor of the four-dimensional brane spacetime. This can be explained as a holographic manifestation. The warped 5D model can be reformulated by considering the warp factor as a dilaton field ($\omega$) conformally coupled to gravity and embedded in a smooth $M_4 \otimes R$ manifold. On the brane, where the U(1) scalar-gauge fields live, the dilaton field manifests itself classically as a warp factor and enters the evolution equations for the metric components and matter fields. We write the Lagrangian for the Einstein-scalar-gauge fields in a conformal invariant setting. However, as expected, the conformal invariance is broken (trace-anomaly) by the appearance of a mass term and a quadratic term in the energy-momentum tensor of the scalar-gauge field, arising from the extrinsic curvature terms of the projected Einstein tensor. These terms can be interpreted as a constraint in order to maintain conformal invariance. By considering the dilaton field and Higgs field on equal footing on small scales, there will be no singular behavior, when $\omega\rightarrow 0$ and one can deduce constraints to maintain regularity of the action. Our conjecture is that $\omega$, alias warp factor, has a dual meaning. At very early times, when $\omega \rightarrow 0$, it describes the small-distance limit, while at later times it is a warp (or scale) factor that determines the dynamical evolution of the universe. We also present a numerical solution of the model and calculate the (time-dependent) trace-anomaly. The solution depends on the mass ratio of the scalar and gauge fields, the parameters of the model and the vortex charge $n$.
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Physical Sciences, Acoustics; alloys; nondestructive testing; dislocation density; plasticity; ultrasound; nonlinear acoustics
Online: 26 October 2018 (08:17:02 CEST)
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The relative dislocation density of aluminum and copper samples is quantitatively measured using linear Resonant Ultrasound Spectroscopy (RUS). For each metallic group, four samples were prepared with different thermomechanical treatments in order to induce changes in their dislocation densities. The RUS results are compared with Nonlinear Resonant Ultrasound Spectroscopy (NRUS) as well as Second Harmonic Generation (SHG) measurements. NRUS has a higher sensitivity by a factor of two to six and SHG by 14% to 62%. The latter technique is, however, faster and simpler. As main a result we obtain a quantitative relation between the changes in the nonlinear parameters and the dislocation density variations, which in a first approximation is a linear relation between these differences. We also present a simple theoretical expression that explains the better sensitivity to dislocation content of the nonlinear parameters with respect to the linear ones. X-Ray diffraction measurements, although intrusive and less accurate, support the acoustics results.
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Physical Sciences, Optics; lens design; numerical methods; DLS; PSD III; global optimization; saddle-point method
Online: 24 October 2018 (05:46:30 CEST)
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Advancement in physics often results from analyzing numerical data and then creating a theoretical model that can explain and predict those data. In the field of lens design, the reverse is true: longstanding theoretical understanding is being overtaken by more powerful numerical methods.
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Physical Sciences, Optics; satellite sensors capturing; spectral- and hyperspectral imaging; atmospheric model; outgoing radiation; atmospheric correction; spectral radiance; surface albedo; spectral brightness factor (coefficient)
Online: 23 October 2018 (15:40:12 CEST)
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Atmospheric correction is a necessary step in image processing data and spectra recorded by spaceborne sensors for pure cloudless atmosphere, primarily in the visible and near-IR spectral range. We have present a fast and sufficiently accurate method of atmospheric correction based on the proposed analytical solutions describing with high accuracy the spectrum of outgoing radiation at the top boundary of the cloudless atmosphere. This technique includes the model of the atmosphere and its optical parameters that are important in terms of radiation transfer. The solution of the inverse problem for finding unknown parameters of the model is carried out by the method of non-linear least squares (Levenberg-Marquardt algorithm) for an individual selected pixel of the image (its spectrum), taking into account the adjacency effects. Using the found parameters of the atmosphere and the average surface albedo, assuming homogeneity of the atmosphere within a certain area of the hyperspectral image (or the whole frame), the spectral albedo at the Earth's surface is calculated for all other pixels. It is essential that the procedure of the numerical simulation with non-linear least squares of the direct transfer problem is based on using analytical solutions, which provides a very short calculation time of the atmospheric parameters (seconds or less) and the ability to perform atmospheric correction "on-fly." Testing methods of atmospheric correction was performed using the synthetic outgoing radiation spectra at the top of the atmosphere (TOA), obtained by numerical simulation in the LibRadTran code, as well as spectra of real space images of the Hyperion hyperspectrometer. A comparison with the results of atmospheric correction in module FLAASH of ENVI package has been performed. Finally, to validate our data obtained by the SHARK method, a comparative analysis with ground-based measurements of Radiometric Calibration Network (RadCalNet) was carried out.
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Physical Sciences, Astronomy & Astrophysics; galaxy morphology, machine learning; data analysis; object classification
Online: 22 October 2018 (13:01:42 CEST)
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Automated machine classifications of galaxies are necessary because the size of upcoming surveys will overwhelm human volunteers. We improve upon existing machine classification methods by adding the output of SpArcFiRe to the inputs of a machine learning model. We use the human classifications from Galaxy Zoo 1 (GZ1) to train a random forest of decision trees to reproduce the human vote distributions of the Spiral class. We prefer the random forest model over other black box models like neural networks because it allows us to trace post hoc the precise reasoning behind the classification of each galaxy. We find that, across a sample of 470,000 Sloan galaxies that are large enough that details could be seen if they were there, the combination of SpArcFiRe outputs with existing SDSS features provides a better machine classification than either one alone on comparison to Galaxy Zoo 1. We suggest that adding SpArcFiRe outputs as features to any machine learning algorithm will likely improve its performance.
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Physical Sciences, Other; diabetes mellitus; blood glucose; kidney; diabetic neuropathy; pancreas
Online: 22 October 2018 (10:45:08 CEST)
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This present study was designed to find out whether the acankoreagenin showed the antidiabetic and renoprotective effects in streptozotocin (STZ)-induced diabetic nephropathy (DN) rats. Type I diabetes was induced by a single intraperitoneal injection of STZ (70 mg/kg). At the end of the experiment, rats were euthanized and serum/plasma was separated for the determination of glucose, insulin, glycated hemoglobin A1c (HbA1c), C-peptide, biochemical parameters, and kidney function. One kidney was used for determining glutathione, superoxide dismutas, malondialdehyde, and tumor necrosis factor-alpha levels. The other kidney and pancreas were used for histopathological studies and immunohistochemical measurement of transforming growth factor beta (TGF-β) or NF-κB. Acankoreagenin (2 mg/kg) treatments led to a significant reduction in blood glucose assessed via oral glucose tolerance test (OGTT) in diabetic rats at 2 h. The treatment also resulted in improved body weight, decreased HbA1c, restored lipid profile, and renal oxidative stress. By inhibiting NF-κB, the release of proinflammatory cytokines was suppressed and by inhibiting TGF-β, the renal fibrosis was suppressed in STZ-induced diabetic rat model. Histopathological injury was also observed in pancreatic and renal tissues. These findings support the beneficial effect of acankoreagenin treatment in DN, which could be attributed to its antidiabetic and renoprotective effects.
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Physical Sciences, Other; ultra-weak photon emission; age; temporal variation; asymmetry; analytical model; photon diffusion
Online: 19 October 2018 (16:40:31 CEST)
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Ultra-weak photon emissions (UPEs) including those from human have been experimented for decades. The photo-genic origin of UPE has also been attributed to the oxidative stress or free radical production that is unique to metabolically active states of biological organisms. However, there are considerable gaps in quantitative understanding of UPE. In this work, I propose an analytical framework of hypothesis for the initial objective of modeling a few superficial presentations of UPE of human, including the systematic dependency on age, the diurnal variation, and the geometric asymmetry associated with serious asymmetrical pathological conditions. The hypothesis which is currently limited to human assumes a new form of energy state, termed vivo-nergy, which resides only in metabolically active organisms that are also under neuronal control. The hypothesis projects a decrease of the vivo-nergy in human during growth beyond puberty, with the rate of decrease dictated by a critical time-scale---the age of the first opposite-sex sexual intercourse (FOSSI). The hypothesis also proposes a modification of the vivo-nergy by the phases of systematic or homeostatic physiology. The hypothesis further postulates that the deviation of the physiology-modified vivo-nergy from the pre-puberty level is deteriorated by acquired organ-specific pathological conditions. Any reduction of vivo-nergy from the pre-puberty level is hypothesized to proportionally cause oxidative stress that functions as the physical source of UPE. The resulted steady-state diffusion of the photon emitted from a photo-genic source of UPE in a human geometry simplified as a homogeneous spherical domain is modeled by photon diffusion principles incorporating an extrapolated zero-boundary condition. The age and systematic physiology combined determines the intensity of the centered physiological photo-genic source. The acquired (single) pathology sets both the intensity and the off-center position of the (single) pathological photo-genic source. When the age-related, physiology-commanded, and pathology-controlled modifications of the photo-genetic sources are implemented in the photon diffusion model, the photon fluence rate at the surface of the simplified human-representing spherical domain reveals the dependency on age, the temporal variation corresponding to systematic physiology, and the geometric asymmetry associated with significant asymmetric pathological condition as reported previously for UPE. The hypothesis, as it provides analytical conveniences for quantitative estimation of UPE patterns, may be useful to further model-based interpretation of the spatial-temporal characteristics of UPE.
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Lino Miramonti,
M. Agostini,
K. Altenmueller,
S. Appel,
V. Atroshchenko,
Z. Bagdasarian,
D. Basilico,
G. Bellini,
J. Benziger,
D. Bick,
I. Bolognino,
G. Bonfini,
D. Bravo,
B. Caccianiga,
F. Calaprice,
A. Caminata,
S. Caprioli,
M. Carlini,
P. Cavalcante,
F. Cavanna,
A. Chepurnov,
K. Choi,
L. Collica,
S. Davini,
A. Derbin,
X.F. Ding,
A. Di Ludovico,
L. Di Noto,
I. Drachnev,
K. Fomenko,
A. Formozov,
D. Franco,
F. Gabriele,
C. Galbiati,
M. Gschwender,
C. Ghiano,
M. Giammarchi,
A. Goretti,
M. Gromov,
D. Guffanti,
C. Hagner,
T. Houdy,
E. Hungerford,
Aldo Ianni,
Andrea Ianni,
A. Jany,
D. Jeschke,
V. Kobychev,
D. Korablev,
G. Korga,
T. Lachenmaier,
M. Laubenstein,
E. Litvinovich,
F. Lombardi,
P. Lombardi,
L. Ludhova,
G. Lukyanchenko,
L. Lukyanchenko,
I. Machulin,
G. Manuzio,
S. Marcocci,
J. Maricic,
J. Martyn,
E. Meroni,
M. Meyer,
M. Misiaszek,
L. Papp,
O. Penek,
L. Pietrofaccia,
N. Pilipenko,
A. Pocar,
A. Porcelli,
G. Raikov,
G. Ranucci,
A. Razeto,
A. Re,
M. Redchuk,
A. Romani,
N. Rossi,
S. Rottenanger,
S. Schönert,
D. Semenov,
M. Skorokhvatov,
O. Smirnov,
A. Sotnikov,
L.F.F. Stokes,
Y. Suvorov,
R. Tartaglia,
G. Testera,
J. Thurn,
M. Toropova,
E. Unzhakov,
A. Vishneva,
R.B. Vogelaar,
F. von Feilitzsch,
S. Weinz,
M. Wojcik,
M. Wurm,
Z. Yokley,
O. Zaimidoroga,
S. Zavatarelli,
K. Zuber,
G. Zuzel
Physical Sciences, Particle & Field Physics; solar neutrinos; neutrino oscillation; Borexino
Online: 19 October 2018 (11:49:06 CEST)
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Solar neutrinos have played a central role in the discovery of the neutrino oscillation mechanism. They still are proving to be a unique tool to help investigate the fusion reactions that power stars and further probe basic neutrino properties. The Borexino neutrino observatory has been operationally acquiring data at Laboratori Nazionali del Gran Sasso in Italy since 2007. Its main goal is the real-time study of low energy neutrinos (solar or originated elsewhere, such as geo-neutrinos). The latest analysis of experimental data, taken during the so-called Borexino Phase-II (2011-present), will be showcased in this talk - yielding new high-precision, simultaneous wide band flux measurements of the four main solar neutrino components belonging to the "pp" fusion chain (pp, pep, 7Be, 8B), as well as upper limits on the remaining two solar neutrino fluxes (CNO and hep).
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Physical Sciences, Optics; THz spectroscopy; 4-methylimidazole; metamaterial; carcinogen detection
Online: 18 October 2018 (11:58:31 CEST)
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We demonstrate, for the first time, a highly sensitive detection of 4-methylimidazole (4-MeI), a carcinogenic material, by applying an electric field enhancement technique using a terahertz (THz) metamaterial at the THz region. The THz metamaterials were fabricated with a metal array using an electric-field-coupled inductor-capacitor (ELC) resonator structure, and FDTD simulation showed good agreement with experimental results. We measured the THz spectra of the metamaterials to detect 4-MeI concentrations of 0, 1, 2, 5, 10, 15, and 20 mg/L. The resonance frequency of the metamaterial was shifted by approximately 8 GHz and transmittance at the resonance frequency increased to 2 x 10-3 as the concentration was increased, up to 20 mg/L. Our study provides new insight into application of metamaterials to detect carcinogen using a THz technique.
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Physical Sciences, Condensed Matter Physics; molecular dynamics; crystal growth; Avrami coefficients; Pt-Pd alloy
Online: 18 October 2018 (10:02:21 CEST)
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This work aims to investigate the effect of Pt concentration on crystal growth mechanism of Platinum-Palladium (Pt-Pd) binary alloy system during the annealing process starting from amorphous phase until some definite temperatures. The calculations have been performed by using molecular dynamic (MD) simulations. Interatomic interactions are described by on Sutton-Chen type Embedded Atom Potential Energy function. In order to understand the main structural properties at the stable and unstable phases, changes in RDF curves versus time have been analysed for different annealing temperatures. Crystalline type bonded pairs have been determined using MD calculations which is required for the computation of Avrami coefficients and for understanding crystal growth mechanism. The results demonstrate that the increase in concentration of Pt during annealing leads to migration of atoms in the crystal lattice points, elimination of dislocations and formation of perfect crystal structure.
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Physical Sciences, Atomic & Molecular Physics; laser induced plasma spectroscopic (LIPS); optical emission spectroscopic (OES); spectroscopy diagnostic; cadmium telluride (CdTe)
Online: 18 October 2018 (04:26:08 CEST)
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In this work, the parameters of plasma (electron temperature (Te), electron density ne, plasma frequency (fp) , Debye length (λD) and Debye number (ND)) have been studied by using the spectrometer that collect the spectrum of Laser produce Cadmium telluride plasma at different energies. The results of electron temperature for CdTe range 0.93-1.18 eV also the electron density 5 × 1010 – 3.8 × 1011 cm-3 have been measured under vacuum reaching 2.5 × 10-2 mbar .Optical properties of CdTe were determined through the optical transmission method using ultraviolet visible spectrophotometer within the range 190 – 1100 nm.
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Physical Sciences, Applied Physics; direct laser writing, multiphoton processing, laser 3D nanolithography, optical 3D printing, microstructures, nanotechnology, mesoscale, two-photon polymerization, microoptics, SZ2080
Online: 17 October 2018 (11:26:32 CEST)
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3D meso-scale structures that can reach up to centimeters in overall size but retain micro- or nano-features, proved to be promising in various science fields ranging from micro-mechanical metamaterials to photonics and bio-medical scaffolds. In this work we present synchronization of the linear and galvano scanners for efficient femtosecond 3D optical printing of objects at the meso-scale (from sub-μm to sub-cm spanning five orders of magnitude). In such configuration the linear stages provide stitch-free structuring at nearly limitless (up to tens-of-cm) working area, while galvo-scanners allow to achieve translation velocities in the range of mm/s-cm/s without sacrificing nano-scale positioning accuracy and preserving undistorted shape of the final print. The principle behind this approach is demonstrated, proving its inherent advantages in comparison to separate use of only linear stages or scanners. The printing rate is calculated in terms voxels/s, showcasing the capability to maintain an optimal feature size while increasing throughput. Full capabilities of this approach are demonstrated by fabricating structures that reach millimeters in size but still retain μm-scale features: scaffolds for cell growth, microlenses and photonic crystals. All this is combined into a benchmark structure: a meso-butterfly. Provided results show that synchronization of two scan modes is crucial for the end goal of industrial-scale implementation of this technology and makes the laser printing well aligned with similar approaches in nanofabrication by electron and ion beams.
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Physical Sciences, Nuclear & High Energy Physics; Strong nuclear gravity, nuclear elementary charge, strong coupling constant, nuclear stability range, binding energy of isotopes, magic proton numbers.
Online: 16 October 2018 (15:28:20 CEST)
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With reference to our earlier published views on large nuclear gravitational constant , nuclear elementary charge and strong coupling constant , in this paper, we present simple relations for nuclear stability range, binding energy of isotopes and magic proton numbers.
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Physical Sciences, Particle & Field Physics; quantum chromodynamics, color confinement, superconformal algebra, conformal symmetry, light-front holography
Online: 16 October 2018 (14:32:58 CEST)
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The QCD Lagrangian is based on quark and gluonic fields -- not squarks nor gluinos. However, one can show that its hadronic eigensolutions conform to a representation of superconformal algebra, reflecting the underlying conformal symmetry of chiral QCD. The eigensolutions of superconformal algebra provide a unified Regge spectroscopy of meson, baryon, and tetraquarks of the same parity and twist as equal-mass members of the same 4-plet representation with a universal Regge slope. The predictions from light-front holography and superconformal algebra can also be extended to mesons, baryons, and tetraquarks with strange, charm and bottom quarks. % The pion $q \bar q$ eigenstate has zero mass for $m_q=0.$ % % A key tool is the remarkable observation of de Alfaro, Fubini, and Furlan (dAFF) which shows how a mass scale can appear in the Hamiltonian and the equations of motion while retaining the conformal symmetry of the action. When one applies the dAFF procedure to chiral QCD, a mass scale $\kappa$ appears which determines universal Regge slopes, hadron masses in the absence of the Higgs coupling. One also predicts the form of the nonperturbative QCD running coupling: $\alpha_s(Q^2) \propto e^{-{Q^2/4 \kappa^2}}$, in agreement with the effective charge determined from measurements of the Bjorken sum rule. One also obtains viable predictions for spacelike and timelike hadronic form factors, structure functions, distribution amplitudes, and transverse momentum distributions. % The combination of conformal symmetry, light-front dynamics, its holographic mapping to AdS$_5$ space, and the dAFF procedure thus provide new insights, not only into the physics underlying color confinement, but also the nonperturbative QCD coupling and the QCD mass scale.
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Physical Sciences, Condensed Matter Physics; graphite; diamagnetism; thickness dependence; susceptibility; interfaces; conductivity; graphene
Online: 16 October 2018 (13:56:35 CEST)
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Recently published structural analysis and galvanomagnetic studies of a large number of different bulk and mesoscopic graphite samples of high quality and purity reveal that the common picture assuming graphite samples as a semimetal with a homogeneous carrier density of conduction electrons is misleading. These new studies indicate that the main electrical conduction path occurs within 2D interfaces embedded in semiconducting Bernal and/or rhombohedral stacking regions. This new knowledge incites us to revise experimentally and theoretically the diamagnetism of graphite samples. We found that the $c$-axis susceptibility of highly pure oriented graphite samples is not really constant but can vary several tens of percent for bulk samples with thickness $t \gtrsim 30~\mu$m, whereas by a much larger factor for samples with smaller thickness. The observed decrease of the susceptibility with sample thickness resembles qualitatively the one reported for the electrical conductivity and indicates that the main part of the $c-$axis diamagnetic signal is not intrinsic of the ideal graphite structure but it is due to the highly conducting 2D interfaces. The interpretation of the main diamagnetic signal of graphite agrees with the reported description of its galvanomagnetic properties and provides a hint to understand some magnetic peculiarities of thin graphite samples.
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Physical Sciences, Mathematical Physics; Born-Jordan, quantization, short time propagator
Online: 16 October 2018 (08:59:09 CEST)
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We have shown in previous work that the equivalence of the Heisenberg and Schrödinger pictures of quantum mechanics requires the use of the Born and Jordan quantization rules. In the present work we give further evidence that the Born--Jordan rule is the correct quantization scheme for quantum mechanics. For this purpose we use correct short-time approximations to the action functional, initially due to Makri and Miller, and show that these lead to the desired quantization of the classical Hamiltonian.
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Physical Sciences, Other; electron paramagnetic resonance; EPR; multi-frequency EPR; high-spin cobalt complex; resolution of A-mid
Online: 16 October 2018 (08:04:16 CEST)
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Low-frequency electron paramagnetic resonance (EPR) is used to extract the EPR parameter A-mid and support the approximate X-band value of g-mid for Ba(CoyZn1/3-yTa2/3)O3. Although cobalt hyperfine structure for the [+/−1/2> state is often unresolved at X-band or S-band, it is resolved in measurements on this compound. This allows for detailed analysis of the molecular orbital for the [+/−1/2> state, which is often the ground state. Moreover, this work shows that the EPR parameters for Co substituted into Zn compounds gives important insight into the properties of zinc binding sites.
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Physical Sciences, Applied Physics; plastic dislocation density tensor
Online: 15 October 2018 (17:32:52 CEST)
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This letter attempts to clarify an issue regarding the proper definition of plastic dislocation density tensor. This study shows that the Ortiz’s and Berdichevsky’s plastic dislocation density tensor are equivalent with each other, but not with Kondo’s one. To fix the problem, we propose a modified version of Kondo’s plastic dislocation density tensor.
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Physical Sciences, Nuclear & High Energy Physics; JUNO; liquid scintillator; neutrino mass hierarchy.
Online: 12 October 2018 (16:38:11 CEST)
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The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator multi-purpose underground detector, under construction near the chinese city of Jiangmen, with data taking expected to start in 2021. The main goal of the experiment is the neutrino mass hierarchy determination, with more than three sigma significance, and the high precision neutrino oscillation parameters measurements, detecting electron anti-neutrinos, emitted from two near-by (baseline of about 53 km) nuclear power plants. Besides, the unprecedented liquid scintillator type detector performance in target mass, energy resolution, energy calibration precision and low-energy threshold, features a rich physics program for the detection of low-energy astrophysical neutrinos, such as galactic core-collapse supernova neutrinos, solar neutrinos and geo-neutrinos.
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Igor Bychkov,
Andrey Demichev,
Julia Dubenskaya,
Oleg Fedorov,
Andreas Haungs,
Andreas Heiss,
Yulia Kazarina,
Elena Korosteleva,
Dmitriy Kostunin,
Alexander Kryukov,
Andrey Mikhailov,
Minh-Duc Nguyen,
Stanislav Polyakov,
Evgeny Postnikov,
Alexey Shigarov,
Dmitry Shipilov,
Achim Streit,
Viktoria Tokareva,
Doris Wochele,
Jürgen Wochele,
Dmitry Zhurov
Physical Sciences, Astronomy & Astrophysics; astroparticle physics, cosmic rays, data life cycle management, data curation, meta data, big data, deep learning, open data
Online: 12 October 2018 (14:48:32 CEST)
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Modern experimental astroparticle physics features large-scale setups measuring different messengers, namely high-energy particles generated by cosmic accelerators (e.g. supernova remnants, active galactic nuclei, etc): cosmic and gamma rays, neutrinos and recently discovered gravitational waves. Ongoing and future experiments are distributed over the Earth including ground, underground/underwater setups as well as balloon payloads and spacecrafts. The data acquired by these experiments have different formats, storage concepts and publication policies. Such differences are a crucial issue in the era of big data and of multi-messenger analysis strategies in astroparticle physics. We propose a service ASTROPARTICLE.ONLINE in the frame of which we develop an open science system which enables to publish, store, search, select and analyse astroparticle physics data. The cosmic-ray experiments KASCADE-Grande and TAIGA were chosen as pilot experiments to be included in this framework. In the first step of our initiative we will develop and test the following components of the full data life cycle concept: (i) describing, storing and reusing of astroparticle data; (ii) software for performing multi-experiment and multi-messenger analyses like deep-learning methods; (iii) outreach including example applications and tutorial for students and scientists outside the specific research field. In the present paper we describe the concepts of our initiative, and in particular the plans toward a common, federated astroparticle data storage.
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Physical Sciences, Optics; PPT symmetry; SL(2, C); hyperbolic geometry
Online: 12 October 2018 (12:42:28 CEST)
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We reelaborate on the basic properties of PT symmetry from a geometrical Perspective. The transfer matrix associated with these systems induces a Möbius transformation in the complex plane. The trace of this matrix classifies the actions into three types that represent rotations, translations, and parallel displacements. We find that a PT invariant system can be pictured as a complex conjugation followed by an inversion in a circle. We elucidate the physical meaning of these geometrical operations and link them with measurable properties of the system.
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Physical Sciences, Nuclear & High Energy Physics; wind speed; wind power; scale factor and shape factor
Online: 12 October 2018 (05:13:33 CEST)
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The research sought to investigate the long term characteristics of wind in the Kisii region (elevation 1710m above sea level, 0.68oS, 34.79o E). Wind speeds were analyzed and characterized on short term (per month for a year) and then simulated for long term (ten years) measured hourly series data of daily wind speeds at a height of 10m. The analysis included daily wind data which was grouped into discrete data and then calculated to represent; the mean wind speed, diurnal variations, daily variations as well as the monthly variations. The wind speed frequency distribution at the height 10 m was found to be 2.9ms-1 with a standard deviation of 1.5. Based on the two month’s data that was extracted from the AcuRite 01024 Wireless Weather Stations with 5-in-1 Weather Sensor experiments set at three sites in the region, averages of wind speeds at hub heights of 10m and 13m were calculated and found to be 1.7m/s, 2.0m/s for Ikobe station, 2.4m/s, 2.8m/s for Kisii University stations, and 1.3m/s, 1.6m/s for Nyamecheo station respectively. Then extrapolation was done to determine average wind speeds at heights (20m, 30m, 50m, and 70m) which were found to be 85.55W/m2, 181.75W/m2, 470.4W/m2 and 879.9W/m2 respectively. The wind speed data was used statistically to model a Weibull probability density function and used to determine the power density for Kisii region.
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Physical Sciences, Condensed Matter Physics; agnetocaloric effect; quantum dot; Aharonov-Bohm
Online: 11 October 2018 (05:53:07 CEST)
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In this work, we report the magnetocaloric effect (MCE) in a quantum dot corresponding to an electron interacting with an antidot, under the effect of an Aharonov-Bohm flux subjected to a parabolic confinement potential. We use the Bogachek and Landman model, which additionally allows the study of quantum dots with Fock-Darwin energy levels for vanishing antidot radius and flux. We find that the Aharonov-Bohm flux (AB-flux) strongly controls the oscillatory behaviour of the MCE, thus acting as a control parameter for the cooling or heating of the magnetocaloric effect. We propose a way to detect AB-flux by measuring temperature differences.
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Physical Sciences, Other; thermodynamics; entropy; artificial intelligence; differential geometry; computational physics
Online: 10 October 2018 (05:19:04 CEST)
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Because only two variables are needed to characterize a simple thermodynamic system in equilibrium, any such system is constrained on a 2D manifold. Of particular interest are the exact 1-forms on the cotangent space of that manifold, since the integral of exact 1-forms is path-independent, a crucial property satisfied by state variables such as internal energy dE and entropy dS. Our prior work [1] shows that given an appropriate language of vector calculus, a machine can re-discover the Maxwell equations and the incompressible Navier-Stokes equations from data. In this paper, We enhance this language by including differential forms and show that machines can re-discover the equation for entropy dS given data. Since entropy appears in various fields of science in different guises, a potential extension of this work is to use the machinery developed in this paper to let machines discover the expressions for entropy from data in fields other than classical thermodynamics.
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Physical Sciences, Condensed Matter Physics; granular materials; displacement fluctuations; $q$-gaussian; strain localization
Online: 9 October 2018 (05:13:57 CEST)
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The statistics of grain displacements probability distribution function (pdf) during the shear of a granular medium displays an unusual dependence with the shear increment upscaling as recently evinced [Phys. Rev. Lett. 115 238301 2015]. Basically, the pdf of grain displacements has clear nonextensive ($q$-Gaussian) features at small scales but approaches to Gaussian characteristics at large shear window scales -- the granulence effect. Here, we extend this analysis studying a larger system (more grains considered in the experimental setup) which exhibits a severe shear band fault during the macroscopic straining. We calculate the pdf of grain displacements and the dependency of the $q$-statistics with the shear increment. This analysis have shown a singular behavior of $q$ at large scales, displaying a non-monotonic dependence with the shear increment. By means of an independent image analysis, we demonstrate that this singular non-monotonicity could be associated with the emergence of a shear band within the confined system. We show that the exact point where the $q$-value inverts its tendency coincides with the emergence of a giant percolation cluster along the system, caused by the shear band. We believe that this original approach using Statistical Mechanics tools to identify shear bands can be a very useful piece to solve the complex puzzle of the rheology of dense granular systems.