Hall effect noise: Fluctuations in number or mobility?

The purpose of this paper is to show that the 1/f noise in the Hall voltage as reported by Brophy and Rostoker can be interpreted in terms of fluctuations in the mobility of free-charge carriers. Brophy and Rostoker have claimed that 1/f noise in the Hall voltage is a direct proof of 1/f fluctuations in the free-carrier density. Their conclusion is shown to be wrong.     

Intermittency or noise – an experimental study on the ion-beam driven ion-acoustic instability

Ion-acoustic waves are destabilised in a double-plasma device by ion-beam-plasma interaction. The plasma system destabilises via a supercritical Hopf-bifurcation with the control parameter being subject to noise. This leads to erratic fluctuations between stable and oscillatory states. The experimental results, in particular the statistical properties, show that this has to be distinguished from type-I intermittency transition to chaos as reported previously for similar experimental setups.     

“Could charm (& τ ) transitions be the ‘poor princess’ providing a deeper understanding of fundamental dynamics ?” or: “Finding novel forces”

We know that our Universe is composed of only ～4.5% “known” matter; therefore, our understanding is incomplete. This can be seen directly in the case of neutrino oscillations (without even considering potential other universes). Charm quarks have had considerable impact on our understanding of known matter, and quantum chromodynamics (QCD) is the only local quantum field theory to describe strong forces. It is possible to learn novel lessons concerning strong dynamics by measuring rates around the thresholds of [QˉQ] states with Q = b, c. Furthermore, these states provide us with gateways towards new dynamics (ND), where we must transition from “accuracy” to “precision” eras. Finally, we can make connections with τ transitions and, perhaps, with dark matter. Charm dynamics acts as a bridge between the worlds of light- and heavy-flavor hadrons (namely, beauty hadrons), and finding regional asymmetries in many-body final states may prove to be a “game changer”. There are several different approaches to achieving these goals: for example, experiments such as the Super Tau-Charm Factory, Super Beauty Factory, and the Super Z⁰ Factory act as gatekeepers – and deeper thinking regarding symmetries.     

Density Isomers or Δ-Matter1?

We demonstrate that the appearance of the density isomers depends on the meson-nucleon coupling strengths in addition to the meson-delta coupling strengths within the mean field theory. Furthermore, thein-medium NN → NΔ cross section is studied with different values of the coupling strengths for deltas. We have found that the in-medium NN → NΔ cross section substantially increases with the increasing of scalar meson-delta coupling strength even for the case when the density isomers do not appear within the mean field theory, which shows the possibility of creating Δ-matter in energetic heavy-ion collisions.     

Can colored noise improve stochastic resonance?

The phenomenon of stochastic resonance is studied in the presence of colored noise. Several sources of colored noise are introduced and the consequences for the asymptotic time-periodic probability and the (phase-averaged) power spectrum are discussed. Based on space-time symmetry considerations, selection rules for the occurrence of-spikes in the power spectrum are derived. The effect of colored noise on the amplification of small periodic signals is studied in terms of effective, time-periodic Fokker-Planck equations: In overdamped systems driven by colored noise, we find that SR is suppressed with increasing noise color. In contrast, for colored noise induced by inertia (as well as for asymmetric dichotomic noise), one obtains an enhancement of SR. This latter result is obtained by studying the Kramers equation perturbed by a small periodic force.     

When does noise increase the quantum capacity?

Superactivation is the property that two channels with zero quantum capacity can be used together to yield a positive capacity. Here we demonstrate that this effect exists for a wide class of inequivalent channels, none of which can simulate each other. We also consider the case where one of two zero-capacity channels is applied, but the sender is ignorant of which one is applied. We find examples where the greater the entropy of mixing of the channels, the greater the lower bound for the capacity. Finally, we show that the effect of superactivation is rather generic by providing an example of superactivation using the depolarizing channel.     

The structure of solid salt eutectics — – Why lamellar or conglomerate?

Using KCl/ZnSO₄ eutectic it has been shown that cooling the melt into a room temperature enclosure forms a lamellar structure, whereas cooling into a heated enclosure (225 °C) forms a conglomerate structure, while an enclosure temperature of 125 °C gave a partially conglomerate structure with some lamellae in process of forming conglomerates.Consideration of the thermal gradients imposed on solidification and consequently the relative time available during which the ions are sufficiently mobile to rearrange their positions, can explain the observation that lamellar structures are formed by higher melting point eutectics, whereas eutectics of lower melting point form conglomerate structures.     

Preferable solar cell absorber – Near stoichiometric or stoichiometric CBD CIAS thin films?

Near stoichiometric and stoichiometric [CuIn_(1 − x)Al_(x)Se₂] (CIAS) thin films are prepared by chemical bath deposition (CBD) technique. X-ray diffraction (XRD) analysis have been employed to estimate the structural properties of CBD CIAS thin films and also to identify the near stoichiometric in particular defect free Cu-poor CBD CIAS thin films as preferable solar cell absorber material.     

Environmental dosimetry with the BeOSL personal dosimeter – State of the Art

In the course of this work, the possibility of the measurement of ambient dose equivalent H*(10) with the BeOSL dosimetry system was evaluated. Calculations for the energy response of the 2-element BeOSL dosimeter for irradiation with H*(10) were performed. The response doesn't fulfil the requirements of IEC 62387-1. Especially the response for photon energies of 60–100 keV is to low. It is possible to correct this under response using a modified BeOSL 2-element dosimeter and a linear algorithm. So the national requirements for a H*(10) dosimeter in Germany can be fulfilled. An incidence angle independent measurement is not possible because for several angles of incidences (>60°) the filters of the 2-element dosimeter doesn't shield the correct element. Another material which is more suitable for the H*(10) measurement was tested. So the doping of BeO with Lanthanum leads to an enhanced energy response for measurement of H*(10). Furthermore a higher OSL sensitivity was found for this material. Further tests on the influence of Lanthanum concentration on the dosimetric properties are necessary.     

Mixed-Up-Ness or Entropy?

Simple SummaryThe second law of thermodynamics has a mystical appeal in disciplines with tenuous connections to its origins. We hypothesize that many of these appeals instead should be to another principle heretofore unrecognized: the law of mixed-up-ness (LOM). Instead of using a number such as entropy to characterize randomness, non-thermodynamic systems can be arranged in simple diagrams according to their degree of mixed-up-ness. Curiously, the evolution of such systems from degrees of low to high mixed-up-ness is both consistent with and richer than the principle of increasing entropy.AbstractMixed-up-ness can be traced to unpublished notes by Josiah Gibbs. Subsequently, the concept was developed independently, and under somewhat different names, by other investigators. The central idea of mixed-up-ness is that systems states can be organized in a hierarchy by their degree of mixed-up-ness. In its purest form, the organizing principle is independent of thermodynamic and statistical mechanics principles, nor does it imply irreversibility. Yet, Gibbs and subsequent investigators kept entropy as the essential concept in determining system evolution, thus retaining the notion that systems evolve from states of perfect “order” to states of total “disorder”. Nevertheless, increasing mixed-up-ness is consistent with increasing entropy; however, there is no unique one-to-one connection between the two. We illustrate the notion of mixed-up-ness with an application to the permutation function of integer partitions and then formalize the notion of mixed-up-ness as a fundamental hierarchal principle, the law of mixed-up-ness (LOM), for non-thermodynamic systems.     

Quintessence or Phoenix?

We show that it is impossible to determine the state equation of quintessence models on the basis of pure observational SNIa data. An independent estimate of _M0 is necessary. Also in this most favourable case the situation can be problematic.     

Adaptive iterated function systems filter for images highly corrupted with fixed – Value impulse noise

The Adaptive Iterated Functions Systems (AIFS) Filter presented in this paper has an outstanding potential to attenuate the fixed-value impulse noise in images. This filter has two distinct phases namely noise detection and noise correction which uses Measure of Statistics and Iterated Function Systems (IFS) respectively. The performance of AIFS filter is assessed by three metrics namely, Peak Signal-to-Noise Ratio (PSNR), Mean Structural Similarity Index Matrix (MSSIM) and Human Visual Perception (HVP). The quantitative measures PSNR and MSSIM endorse the merit of this filter in terms of degree of noise suppression and details/edge preservation respectively, in comparison with the high performing filters reported in the recent literature. The qualitative measure HVP confirms the noise suppression ability of the devised filter. This computationally simple noise filter broadly finds application wherein the images are highly degraded by fixed-value impulse noise.     

Can a ‘magnesium sulfate admixtured l-threonine’ crystal be grown by slow evaporation solution growth method?

Slow evaporation of an aqueous solution containing l-threonine and magnesium sulphate heptahydrate, results in the fractional crystallization of the less soluble l-threonine crystal and not any novel optoelectronic ‘magnesium sulfate admixtured l-threonine’ crystal as reported by Puhal Raj et al. in Optik, 124 (2013) 6887–6891.     

Editorial – Introductory remarks on “Discussion &; Debate: Rogue Waves – Towards a Unifying Concept?”

This short editorial contains the introductory remarks for the special issue “discussions and debates” on the subject of “rogue waves”. This issue is the first of its kind, in the sense that the authors have the chance to discuss the basic concepts of an emerging topic in science. Based on these discussions, an attempt to give a “definition” of a rogue wave is made.     

Sound field characteristics of underground railway stations – Effect of interior materials and noise source positions

In the case of most underground railway stations, no acoustical solutions are used to reduce train noise. Because the reflecting features of train noise in an underground station are not known, appropriate methods for controlling these features have yet to be established. The aim of this study was to clarify the sound field characteristics of underground stations by putting a sound source and receiver on the railway track and platform, respectively. The impulse responses for two vacant underground stations were measured to clarify the effects of the interior materials of the station (Comparison I), and the sound source was put in each station and tunnel to clarify the effect of the noise source positions (Comparison II). Results showed that the sound fields were similar between the stations whose lateral walls were covered with either metallic or fire-resistant wooden panels (Comparison I), and that the sound field for the sound sources near or in the tunnel presented a higher strength (G) by 5.1 dB and longer reverberation time (EDT) by 0.7 s compared to the sound source in the station (Comparison II). The sound sources in the tunnel presented strong and long reverberations at around 500 Hz due to the convergence effect of the tunnel. Therefore, this study proposes a platform screen with doors to limit noise transmission into the platform.     

Single or triple gradients?

Pulsed Field Gradients (PFGs) have become ubiquitous tools not only for Magnetic Resonance Imaging (MRI), but also for NMR experiments designed to study translational diffusion, for spatial encoding in ultra-fast spectroscopy, for the selection of desirable coherence transfer pathways, for the suppression of solvent signals, and for the elimination of zero-quantum coherences. Some of these experiments can only be carried out if three orthogonal gradients are available, while others can also be implemented using a single gradient, albeit at some expense of performance. This paper discusses some of the advantages of triple- with respect to single-gradient probes. By way of examples we discuss (i) the measurement of small diffusion coefficients making use of the long spin-lattice relaxation times of nuclei with low gyromagnetic ratios gamma such as nitrogen-15, and (ii) the elimination of zero-quantum coherences in Exchange or Nuclear Overhauser Spectroscopy (EXSY or NOESY) experiments, as well as in methods relying on long-lived (singlet) states to study very slow exchange or diffusion processes.     

Dark halo or bigravity?

Observations show that about the of the Universe iscomposed by invisible (dark) matter (DM), for which manycandidates have been proposed. In particular, the anomalousbehavior of rotational curves of galaxies (i.e. theflattening at large distance instead of the Keplerian fall)requires thatthis matter is distributed in an extended halo around the galaxy. In order to reproduce this matter density profiles in Newtonian gravity and in cold dark matter (CDM) paradigm (in which theDM particles are collisionless), many ad-hoc approximations are required.The flattening of rotational curves can be explained by asuitable modification of gravitational force in bigravity theories, together with mirror matter model that predicts the existenceof a dark sector in which DM has the same physical properties of visible matter.As an additional result, the Newton constant is different at distances much less and much greater than 20 kpc.