bluuebunny/crossref_metadata_2025 huggingface dataset:
Apis tanzt im Ensemble
Authors: Simon Andrea , Etter Andreas J
Published: August 2017

„Sepia tanzt allein“ heißt der Bildband von Andrea Simon und Andreas J. Etter. Er vereint Homöopathie, Tanz und Fotografie. DHZ-Redakteur Alphan Cicekten traf das Künstlerduo in einem lichtdurchfluteten Fotostudio in Mainz.
Advance directives and knowledge of future selves
Authors: Buford Christopher
Published: August 2017

A number of concerns have been raised with respect to advance directives. Advance directives are intended to allow a person who is currently capable of giving informed consent to determine how they are to be treated at a later time at which they are not competent to give such consent. For example, an advance directive such as a living will might specify that should a patient face severe dementia, certain forms of treatment should not be provided if needed to prolong life. Or an individual might fill out a do-not-resuscitate order asking not to be revived in the event of a heart attack. This article discusses three distinct arguments that have been offered against the legitimacy of some or all advance directives. After laying out each argument, focus is given to a potential response to one of the arguments in particular, an argument labelled the “Ignorance Argument”. The argument contends that the potential application of any advance directive is plagued by a host of epistemic issues that are serious enough to hamper the very expression of autonomy advance directives are designed to allow for. A possible response to the argument is developed. The response suggests that the argument may place unduly severe constraints on the type of self-knowledge needed to underwrite the expression of a person’s autonomy through the creation of an advance directive. The response identifies some connections between the different arguments. An answer is also given to a recent criticism, offered by Eric Vogelstein (2016), which questions the existence of the type of autonomy needed to underwrite advance directives.
Single-channel labyrinthine metasurfaces as perfect sound absorbers with tunable bandwidth
Authors: Liu Liu , Chang Huiting , Zhang Chi , Hu Xinhua
Published: August 2017

Perfect sound absorbers with a deep-subwavelength thickness are important to applications such as noise reduction and sound detection. But their absorption bandwidths are usually narrow and difficult to adjust. A recent solution for this problem relies on multiple-resonator metasurfaces, which are hard to fabricate. Here, we report on the design, fabrication, and characterization of a single-channel labyrinthine metasurface, which allows total sound absorption at resonant frequency when appropriate amounts of porous media (or critical sound losses) are introduced in the channels. The absorption bandwidth can be tuned by changing the cross-sectional areas of channels. A tradeoff is found between the absorption bandwidth and the metasurface thickness. However, large tunability in the relative absorption bandwidth (from 17% to 121%) is still attainable by such metasurfaces with a deep-subwavelength thickness (0.03–0.13λ).
Aluminum ultraviolet–visible plasmonic arrays for broadband and wavelength-selective enhancements of quantum dot emission
Authors: Kannegulla A. , Liu Y. , Wu B. , Cheng L.-J.
Published: August 2017

Enhancement of spontaneous emission can be achieved by the interaction between quantum emitters and the free electrons on metal surfaces, which creates additional energy relaxation channels through plasmon excitations. It can also be realized by extra near-field excitation of quantum emitters through surface plasmons created by absorption of far-field illumination. By using aluminum dimple arrays with their surface plasmon resonances (SPRs) tunable to span from the visible to UV regions, we demonstrate the control of the quantum dot (QD)-SPR coupling routes to realize either wavelength-selective enhancement of QD emission or broadband enhancement of multicolor QDs. The cost effective Al plasmonic structures enable enhancement of light emission and excitation at tailorable wavelengths and could advance the performance and design flexibility of light-emitting devices and photovoltaic technologies.
Non-equilibrium surface tension of the vapour-liquid interface of active Lennard-Jones particles
Authors: Paliwal Siddharth , Prymidis Vasileios , Filion Laura , Dijkstra Marjolein
Published: August 2017

We study a three-dimensional system of self-propelled Brownian particles interacting via the Lennard-Jones potential. Using Brownian dynamics simulations in an elongated simulation box, we investigate the steady states of vapour-liquid phase coexistence of active Lennard-Jones particles with planar interfaces. We measure the normal and tangential components of the pressure tensor along the direction perpendicular to the interface and verify mechanical equilibrium of the two coexisting phases. In addition, we determine the non-equilibrium interfacial tension by integrating the difference of the normal and tangential components of the pressure tensor and show that the surface tension as a function of strength of particle attractions is well fitted by simple power laws. Finally, we measure the interfacial stiffness using capillary wave theory and the equipartition theorem and find a simple linear relation between surface tension and interfacial stiffness with a proportionality constant characterized by an effective temperature.
Thermal energy conversion using near-field thermophotovoltaic device composed of a thin-film tungsten radiator and a thin-film silicon cell
Authors: Lau Japheth Z.-J. , Wong Basil T.
Published: August 2017

In this paper, we proposed a novel nano-gap thermophotovoltaic (TPV) device made up of thin-films including the radiator. The optical, electrical, and thermal responses and performance of the device were assessed using coupled opto-electro-thermal numerical simulation. The device design consists of a thin-film tungsten radiator which is paired with a thin-film silicon TPV cell across a nanometric vacuum gap. Results were simulated based on experimental properties available in the current literature database. It is discovered that the maximum electrical power output of the thin-film nano-gap TPV device increases with cell temperature up to a certain threshold value due to improvements in generated photocurrent. Thin-film tungsten as a radiator is shown to improve radiative heat transfer above the bandgap compared to conventional bulk tungsten. The effect of cell thickness on responses and performance was also analysed. A 1-μm cell produces better performance over thinner thicknesses at the cost of greater cooling requirements. However, the improvements in output power offset the cooling costs, allowing for consistently favourable efficiencies. Finally, it is shown that the temperature profile in silicon thin-films under convective cooling can be approximated as uniform, simplifying the heat transport modelling process.
Study of the enhanced electromigration performance of Cu(Mn) by low-frequency noise measurements and atom probe tomography
Authors: Beyne Sofie , Arnoldi Laurent , De Wolf Ingrid , Tőkei Zsolt , Croes Kristof
Published: August 2017

The enhanced electromigration (EM) performance of 20 nm-wide Cu interconnects with a Mn-doped Cu seed and a Mn-based barrier is studied by means of low-frequency (LF) noise measurements and atom probe tomography (APT). While the EM activation energy of reference interconnects without Mn is 0.8 eV, standard EM tests revealed an activation energy of 1.0 eV for Cu(Mn) interconnects. The LF noise measurements confirm the activation energy of 1.0–1.1 eV in the Cu(Mn) interconnects, but also the activation energy of 0.8 eV is still visible, though less pronounced. Furthermore, the extent to which the mechanism at 0.8 eV is suppressed is strongly subjected to sample variations. These observations are confirmed by APT; Mn is found at the top surface and small clusters of Mn are present in the Cu bulk up to 5 nm away from the sidewalls. Mn segregation at the grain boundaries was not observed such that the hypothesis of Mn blocking grain boundary diffusion cannot be confirmed.
Conversion between EIT and Fano spectra in a microring-Bragg grating coupled-resonator system
Authors: Zhang Zecen , Ng Geok Ing , Hu Ting , Qiu Haodong , Guo Xin , Wang Wanjun , Rouifed Mohamed Saïd , Liu Chongyang , Wang Hong
Published: August 2017

A conversion between the electromagnetically induced transparency (EIT) transmission and Fano transmission is theoretically and experimentally demonstrated in an all-pass microring-Bragg grating (APMR-BG) coupled-resonator system. In this work, the coupling between the two resonators (the microring resonator and the Fabry-Perot resonator formed by two Bragg gratings) gives rise to the EIT and Fano transmissions. The resonant status strongly depends on the round-trip attenuation of the microring and the coupling strength. By tuning the coupling strength, the EIT and Fano transmissions can be controlled and converted. The device performance has been theoretically calculated and analyzed with a specially developed numerical model based on the transfer matrix method. The APMR-BG coupled-resonator systems with different gap widths were designed, fabricated, and characterized on a silicon-on-insulator (SOI) platform. The conversion of resonance was experimentally observed and verified. In addition, this on-chip system has the advantage of a small footprint, and the fabrication process is compatible with the planar waveguide fabrication process.
Full-wave finite space model of open-ended coaxial line for dielectric spectroscopy of liquids
Authors: Jablonskas D. , Lapinskas S. , Rudys S. , Ivanov M. , Banys J.
Published: August 2017

The physical equipment was built according to the mathematical model and tested. The performance of equipment is demonstrated measuring two known liquids, methanol and isopropanol, up to 40 GHz. The accuracy and sensitivity, and the versatility and ease of manufacturing of the measurement cell are discussed.
Dispersion characteristics of THz surface plasmons in nonlinear graphene-based parallel-plate waveguide with Kerr-type core dielectric
Authors: Yarmoghaddam Elahe , Rakheja Shaloo
Published: August 2017

We theoretically model the dispersion characteristics of surface plasmons in a graphene-based parallel-plate waveguide geometry using nonlinear Kerr-type core (inter-plate) dielectric. The optical nonlinearity of graphene in the terahertz band under high light intensity is specifically included in the analysis. By solving Maxwell's equations and applying appropriate boundary conditions, we show that the waveguide supports four guided plasmon modes, each of which can be categorized as either symmetric or anti-symmetric based on the electric field distribution in the structure. Of the four guided modes, two modes are similar in characteristics to the modes obtained in the structure with linear graphene coating, while the two new modes have distinct characteristics as a result of the nonlinearity of graphene. We note that the group velocity of one of the plasmon modes acquires a negative value under high light intensity. Additionally, the optical nonlinearity of the core dielectric leads to a significant enhancement in the localization length of various plasmon modes. The description of the intra-band optical conductivity of graphene incorporates effects of carrier scatterings due to charged impurities, resonant scatterers, and acoustic phonons at 300 K. The proposed structure offers flexibility to tune the waveguide characteristics and the mode index by changing light intensity and electrochemical potential in graphene for reconfigurable plasmonic devices.
The impact of charge compensated and uncompensated strontium defects on the stabilization of the ferroelectric phase in HfO2
Authors: Materlik Robin , Künneth Christopher , Mikolajick Thomas , Kersch Alfred
Published: August 2017

Different dopants with their specific dopant concentration can be utilized to produce ferroelectric HfO2 thin films. In this work, it is explored for Sr in a comprehensive first-principles study. Density functional calculations reveal structure, formation energy, and total energy of the Sr related defects in HfO2. We found the charge compensated defect with an associated oxygen vacancy SrHfVO to strongly favour the non-ferroelectric, tetragonal P42/mnc phase energetically. In contrast, the uncompensated defect without oxygen vacancy SrHf favours the ferroelectric, orthorhombic Pca21 phase. According to the formation energy, the uncompensated defect can form easily under oxygen rich conditions in the production process. Low oxygen partial pressure existing over the lifetime promotes the loss of oxygen leading to VO, and thus, the destabilization of the ferroelectric, orthorhombic Pca21 phase is accompanied by an increase of the leakage current. This study attempts to fundamentally explain the stabilization of the ferroelectric, orthorhombic Pca21 phase by doping.
Tailoring the multipoles in THz toroidal metamaterials
Authors: Cong Longqing , Srivastava Yogesh Kumar , Singh Ranjan
Published: August 2017

The multipoles play a significant role in determining the resonant behavior of subwavelength resonators that form the basis of metamaterial and plasmonic systems. Here, we study the impact of multipoles including toroidal dipole on the resonance intensity and linewidth of the fundamental inductive-capacitance (LC) resonance of a metamaterial array. The dominant multipoles that strongly contribute to the resonances are tailored by spatial rearrangement of the neighboring resonators such that the mutual interactions between the magnetic, electric, and toroidal configurations lead to enormous change in the linewidth as well as the resonance intensity of the LC mode. Manipulation of the multipoles in a metamaterial array provides a general strategy for the optimization of the quality factor of metamaterial resonances, which is fundamental to its applications in broad areas of sensing, lasing and nonlinear optics where stronger field confinement plays a significant role.
Effects of a chirped bias voltage on ion energy distributions in inductively coupled plasma reactors
Authors: Lanham Steven J. , Kushner Mark J.
Published: August 2017

The metrics for controlling reactive fluxes to wafers for microelectronics processing are becoming more stringent as feature sizes continue to shrink. Recent strategies for controlling ion energy distributions to the wafer involve using several different frequencies and/or pulsed powers. Although effective, these strategies are often costly or present challenges in impedance matching. With the advent of matching schemes for wide band amplifiers, other strategies to customize ion energy distributions become available. In this paper, we discuss results from a computational investigation of biasing substrates using chirped frequencies in high density, electronegative inductively coupled plasmas. Depending on the frequency range and chirp duration, the resulting ion energy distributions exhibit components sampled from the entire frequency range. However, the chirping process also produces transient shifts in the self-generated dc bias due to the reapportionment of displacement and conduction with frequency to balance the current in the system. The dynamics of the dc bias can also be leveraged towards customizing ion energy distributions.
Dilution effects on combined magnetic and electric dipole interactions: A study of ferromagnetic cobalt nanoparticles with tuneable interactions
Authors: Hod M. , Dobroserdova A. , Samin S. , Dobbrow C. , Schmidt A. M. , Gottlieb M. , Kantorovich S.
Published: August 2017

Improved understanding of complex interactions between nanoparticles will facilitate the control over the ensuing self-assembled structures. In this work, we consider the dynamic changes occurring upon dilution in the self-assembly of a system of ferromagnetic cobalt nanoparticles that combine magnetic, electric, and steric interactions. The systems examined here vary in the strength of the magnetic dipole interactions and the amount of point charges per particle. Scattering techniques are employed for the characterization of the self-assembly aggregates, and zeta-potential measurements are employed for the estimation of surface charges. Our experiments show that for particles with relatively small initial number of surface electric dipoles, an increase in particle concentration results in an increase in diffusion coefficients; whereas for particles with relatively high number of surface dipoles, no effect is observed upon concentration changes. We attribute these changes to a shift in the adsorption/desorption equilibrium of the tri-n-octylphosphine oxide (TOPO) molecules on the particle surface. We put forward an explanation, based on the combination of two theoretical models. One predicts that the growing concentration of electric dipoles, stemming from the addition of tri-n-octylphosphine oxide (TOPO) as co-surfactant during particle synthesis, on the surface of the particles results in the overall repulsive interaction. Secondly, using density functional theory, we explain that the observed behaviour of the diffusion coefficient can be treated as a result of the concentration dependent nanoparticle self-assembly: additional repulsion leads to the reduction in self-assembled aggregate size despite the shorter average interparticle distances, and as such provides the growth of the diffusion coefficient.
Zero curvature-surface driven small objects
Authors: Dou Xiaoxiao , Li Shanpeng , Liu Jianlin
Published: August 2017

In this study, we investigate the spontaneous migration of small objects driven by surface tension on a catenoid, formed by a layer of soap constrained by two rings. Although the average curvature of the catenoid is zero at each point, the small objects always migrate to the position near the ring. The force and energy analyses have been performed to uncover the mechanism, and it is found that the small objects distort the local shape of the liquid film, thus making the whole system energetically favorable. These findings provide some inspiration to design microfluidics, aquatic robotics, and miniature boats.
Characterization of the anisotropy of rough surfaces: Crossing statistics
Authors: Ghasemi Nezhadhaghighi M. , Movahed S. M. S. , Yasseri T. , Vaez Allaei S. Mehdi
Published: August 2017

In this paper, we propose the use of crossing statistics and its generalizations as a new framework to characterize the anisotropy of a 2D rough surface. The proposed method is expandable to higher dimensions. By measuring the number of up-crossing, ν+ [crossing points with a positive slope at a given threshold of height (α)], and the generalized roughness function, Ntot, it is possible to characterize the nature of an anisotropy, rotational invariance, and Gaussianity of any given surface. In the case of anisotropic correlated self- or multi-affine surfaces, even with different correlation lengths in different directions and/or directional scaling exponents, we examine the relationship between ν+ and Ntot, and corresponding scaling parameters analytically. The method identifies the direction of anisotropy through the systematic use of P-value statistics. After applying the common methods in determining the corresponding scaling exponents in the identified anisotropic directions, we are able to determine the type and the ratio of the involved correlation lengths. To demonstrate capability and accuracy of the method, as well as to validate the analytical calculations, we apply the proposed measures on synthetic stochastic rough interfaces and rough interfaces generated from the simulation of ion etching. There is a good agreement between analytical results and the outcomes of the numerical models. The proposed algorithm can be implemented through a simple software in various instruments, such as AFM and STM, for surface analysis and characterization.
Small amplitude waves and linear firehose and mirror instabilities in rotating polytropic quantum plasma
Authors: Bhakta S. , Prajapati R. P. , Dolai B.
Published: August 2017

The small amplitude quantum magnetohydrodynamic (QMHD) waves and linear firehose and mirror instabilities in uniformly rotating dense quantum plasma have been investigated using generalized polytropic pressure laws. The QMHD model and Chew–Goldberger–Low (CGL) set of equations are used to formulate the basic equations of the problem. The general dispersion relation is derived using normal mode analysis which is discussed in parallel, transverse, and oblique wave propagations. The fast, slow, and intermediate QMHD wave modes and linear firehose and mirror instabilities are analyzed for isotropic MHD and CGL quantum fluid plasmas. The firehose instability remains unaffected while the mirror instability is modified by polytropic exponents and quantum diffraction parameter. The graphical illustrations show that quantum corrections have a stabilizing influence on the mirror instability. The presence of uniform rotation stabilizes while quantum corrections destabilize the growth rate of the system. It is also observed that the growth rate stabilizes much faster in parallel wave propagation in comparison to the transverse mode of propagation. The quantum corrections and polytropic exponents also modify the pseudo-MHD and reverse-MHD modes in dense quantum plasma. The phase speed (Friedrichs) diagrams of slow, fast, and intermediate wave modes are illustrated for isotropic MHD and double adiabatic MHD or CGL quantum plasmas, where the significant role of magnetic field and quantum diffraction parameters on the phase speed is observed.
Cylindrical shock waves in rotational axisymmetric non-ideal dusty gas with increasing energy under the action of monochromatic radiation
Authors: Sahu P. K.
Published: August 2017

The propagation of a cylindrical shock wave in a rotational axisymmetric non-ideal dusty gas under the action of monochromatic radiation with increasing energy, which has variable azimuthal and axial components of fluid velocity, is investigated. The dusty gas is assumed to be a mixture of non-ideal (or perfect) gas and small solid particles, in which solid particles are continuously distributed. Similarity solutions are obtained as well as the effects of the variation of the radiation parameters, the parameter of non-idealness of the gas, the mass concentration of solid particles in the mixture, the ratio of the density of solid particles to the initial density of the gas, and the piston velocity index are worked out in detail. The total energy of the shock wave is varying and increases with time. It is observed that the radiation parameter and the piston velocity index have opposite behaviour on the flow variables as well as the shock strength.

The author of the article agrees to the retraction of the article effective AUGUST 12, 2021.
Acoustics of multiscale sorptive porous materials
Authors: Venegas R. , Boutin C. , Umnova O.
Published: August 2017

This paper investigates sound propagation in multiscale rigid-frame porous materials that support mass transfer processes, such as sorption and different types of diffusion, in addition to the usual visco-thermo-inertial interactions. The two-scale asymptotic method of homogenization for periodic media is successively used to derive the macroscopic equations describing sound propagation through the material. This allowed us to conclude that the macroscopic mass balance is significantly modified by sorption, inter-scale (micro- to/from nanopore scales) mass diffusion, and inter-scale (pore to/from micro- and nanopore scales) pressure diffusion. This modification is accounted for by the dynamic compressibility of the effective saturating fluid that presents atypical properties that lead to slower speed of sound and higher sound attenuation, particularly at low frequencies. In contrast, it is shown that the physical processes occurring at the micro-nano-scale do not affect the macroscopic fluid flow through the material. The developed theory is exemplified by introducing an analytical model for multiscale sorptive granular materials, which is experimentally validated by comparing its predictions with acoustic measurements on granular activated carbons. Furthermore, we provide empirical evidence supporting an alternative method for measuring sorption and mass diffusion properties of multiscale sorptive materials using sound waves.
Instability of eccentric compound threads
Authors: Ye Hanyu , Peng Jie , Yang Lijun
Published: August 2017

This paper investigates the temporal instability of an eccentric compound liquid thread. Results of linear stability are obtained for a typical case in the context of compound threads in microencapsulation. It is found that the disturbance growth rate of an eccentric compound liquid thread is close to that of the corresponding concentric one, in terms of both the maximum growth rate and the dominant wavenumber. Furthermore, linear stability results over a wide parameter range are obtained and the conclusion is basically unchanged. Energy balance of the destabilization process is analyzed to explain the mechanism of instability, and it is found that although the disturbance growth rate of an eccentric compound thread is close to that of the corresponding concentric thread, their energy balances are distinctively different. The disturbance interface shape and disturbance velocity distributions are plotted. It is found that the behavior of the disturbance velocity in the cross section plane is different from that of the axial disturbance velocity. The disturbance velocity distributions in the cross section plane explain the trend in the disturbance interface shape. A fully nonlinear simulation of the destabilization process is performed by the Gerris flow solver and the results agree well with those obtained by linear stability analysis.
A multi-frequency electrical impedance tomography system for real-time 2D and 3D imaging
Authors: Yang Yunjie , Jia Jiabin
Published: August 2017

This paper presents the design and evaluation of a configurable, fast multi-frequency Electrical Impedance Tomography (mfEIT) system for real-time 2D and 3D imaging, particularly for biomedical imaging. The system integrates 32 electrode interfaces and the current frequency ranges from 10 kHz to 1 MHz. The system incorporates the following novel features. First, a fully adjustable multi-frequency current source with current monitoring function is designed. Second, a flexible switching scheme is developed for arbitrary sensing configuration and a semi-parallel data acquisition architecture is implemented for high-frame-rate data acquisition. Furthermore, multi-frequency digital quadrature demodulation is accomplished in a high-capacity Field Programmable Gate Array. At last, a 3D imaging software, visual tomography, is developed for real-time 2D and 3D image reconstruction, data analysis, and visualization. The mfEIT system is systematically tested and evaluated from the aspects of signal to noise ratio (SNR), frame rate, and 2D and 3D multi-frequency phantom imaging. The highest SNR is 82.82 dB on a 16-electrode sensor. The frame rate is up to 546 fps at serial mode and 1014 fps at semi-parallel mode. The evaluation results indicate that the presented mfEIT system is a powerful tool for real-time 2D and 3D imaging.
Validation of reverse Hartmann test for mirror shape measurement of parabolic trough concentrator
Authors: Hou Yinlong , Li Lin , Wang Shanshan , Luo Xiaohe , Zhu Qiudong
Published: August 2017

A method for the surface shape qualification of a parabolic trough solar concentrator, based on the reflection of sinusoidal fringes in the mirror surface and their distortions due to the surface deviations from ideal geometry, has been developed. Without complex calibration, accurate surface slope data were collected and reduced by using sixteen-step phase shifting methods. As the gradient data may not be ideally available for the entire surface, surface deviations and geometrical parameters were obtained through Zernike slope polynomials iterative fitting and the Southwell integration algorithm. Additionally, an absolute reference measurement for calibration of the measurement accuracy using three standard mirrors is presented. It is shown that the proposed method can easily test the surface shape and concentration efficiency of a solar concentrator with high slope measurement accuracy (less than 0.05 mrad in the x-direction) and high spatial resolution (more than 2.5 × 106 points per mirror facet).
A tunable single-monochromator Raman system based on the supercontinuum laser and tunable filters for resonant Raman profile measurements
Authors: Liu X.-L. , Liu H.-N. , Tan P.-H.
Published: August 2017

Resonant Raman spectroscopy requires that the wavelength of the laser used is close to that of an electronic transition. A tunable laser source and a triple spectrometer are usually necessary for resonant Raman profile measurements. However, such a system is complex with low signal throughput, which limits its wide application by scientific community. Here, a tunable micro-Raman spectroscopy system based on the supercontinuum laser, transmission grating, tunable filters, and single-stage spectrometer is introduced to measure the resonant Raman profile. The supercontinuum laser in combination with transmission grating makes a tunable excitation source with a bandwidth of sub-nanometer. Such a system exhibits continuous excitation tunability and high signal throughput. Its good performance and flexible tunability are verified by resonant Raman profile measurement of twisted bilayer graphene, which demonstrates its potential application prospect for resonant Raman spectroscopy.
Effects of mechanical feedback on the stability of cardiac scroll waves: A bidomain electro-mechanical simulation study
Authors: Colli Franzone P. , Pavarino L. F. , Scacchi S.
Published: August 2017

In this work, we investigate the influence of cardiac tissue deformation on re-entrant wave dynamics. We have developed a 3D strongly coupled electro-mechanical Bidomain model posed on an ideal monoventricular geometry, including fiber direction anisotropy and stretch-activated currents (SACs). The cardiac mechanical deformation influences the bioelectrical activity with two main mechanical feedback: (a) the geometric feedback (GEF) due to the presence of the deformation gradient in the diffusion coefficients and in a convective term depending on the deformation rate and (b) the mechano-electric feedback (MEF) due to SACs. Here, we investigate the relative contribution of these two factors with respect to scroll wave stability. We extend the previous works [Keldermann et al., Am. J. Physiol. Heart Circ. Physiol. 299, H134–H143 (2010) and Hu et al., PLoS One 8(4), e60287 (2013)] that were based on the Monodomain model and a simple non-selective linear SAC, while here we consider the full Bidomain model and both selective and non-selective components of SACs. Our simulation results show that the stability of cardiac scroll waves is influenced by MEF, which in case of low reversal potential of non-selective SACs might be responsible for the onset of ventricular fibrillation; GEF increases the scroll wave meandering but does not determine the scroll wave stability.
Transport gap renormalization at a metal-molecule interface using DFT-NEGF and spin unrestricted calculations
Authors: Celis Gil J. A. , Thijssen J. M.
Published: August 2017

A method is presented for predicting one-particle energies for a molecule in a junction with one metal electrode, using density functional theory methods. In contrast to previous studies, in which restricted spin configurations were analyzed, we take spin polarization into account. Furthermore, in addition to junctions in which the molecule is weakly coupled, our method is also capable of describing junctions in which the molecule is chemisorbed to the metal contact. We implemented a fully self-consistent scissor operator to correct the highest occupied molecular orbital-lowest unoccupied molecular orbital gap in transport calculations for single molecule junctions. We present results for various systems and compare our results with those obtained by other groups.
Sign and magnitude scaling properties of heart rate variability in patients with end-stage renal failure: Are these properties useful to identify pathophysiological adaptations?
Authors: Lerma Claudia , Echeverría Juan C. , Infante Oscar , Pérez-Grovas Héctor , González-Gómez Hortensia
Published: August 2017

The scaling properties of heart rate variability data are reliable dynamical features to predict mortality and for the assessment of cardiovascular risk. The aim of this manuscript was to determine if the scaling properties, as provided by the sign and magnitude analysis, can be used to differentiate between pathological changes and those adaptations basically introduced by modifications of the mean heart rate in distinct manoeuvres (active standing or hemodialysis treatment, HD), as well as clinical conditions (end stage renal disease, ESRD). We found that in response to active standing, the short-term scaling index (α1) increased in healthy subjects and in ESRD patients only after HD. The sign short-term scaling exponent (α1sign) increased in healthy subjects and ESRD patients, showing a less anticorrelated behavior in active standing. Both α1 and α1sign did show covariance with the mean heart rate in healthy subjects, while in ESRD patients, this covariance was observed only after HD. A reliable estimation of the magnitude short-term scaling exponent (α1magn) required the analysis of time series with a large number of samples (>3000 data points). This exponent was similar for both groups and conditions and did not show covariance with the mean heart rate. A surrogate analysis confirmed the presence of multifractal properties (α1magn > 0.5) in the time series of healthy subjects and ESDR patients. In conclusion, α1 and α1sign provided insights into the physiological adaptations during active standing, which revealed a transitory impairment before HD in ESRD patients. The presence of multifractal properties indicated that a reduced short-term variability does not necessarily imply a declined regulatory complexity in these patients.
Interaction between a surface quasi-geostrophic buoyancy anomaly jet and internal vortices
Authors: Reinaud J. N. , Dritschel D. G. , Carton X.
Published: August 2017

This paper addresses the dynamical coupling of the ocean’s surface and the ocean’s interior. In particular, we investigate the dynamics of an oceanic surface jet and its interaction with vortices at depth. The jet is induced by buoyancy (density) anomalies at the surface. We first focus on the jet alone. The linear stability indicates there are two modes of instability: the sinuous and the varicose modes. When a vortex in present below the jet, it interacts with it. The velocity field induced by the vortex perturbs the jet and triggers its destabilisation. The jet also influences the vortex by pushing it under a region of co-operative shear. Strong jets may also partially shear out the vortex. We also investigate the interaction between a surface jet and a vortex dipole in the interior. Again, strong jets may partially shear out the vortex structure. The jet also modifies the trajectory of the dipole. Dipoles travelling towards the jet at shallow incidence angles may be reflected by the jet. Vortices travelling at moderate incidence angles normally cross below the jet. This is related to the displacement of the two vortices of the dipole by the shear induced by the jet. Intense jets may also destabilise early and form streets of billows. These billows can pair with the vortices and separate the dipole.
Stochastic spontaneous calcium release events and sodium channelopathies promote ventricular arrhythmias
Authors: Campos Fernando O. , Shiferaw Yohannes , Vigmond Edward J. , Plank Gernot
Published: August 2017

Premature ventricular complexes (PVCs), the first initiating beats of a variety of cardiac arrhythmias, have been associated with spontaneous calcium release (SCR) events at the cell level. However, the mechanisms underlying the degeneration of such PVCs into arrhythmias are not fully understood. The objective of this study was to investigate the conditions under which SCR-mediated PVCs can lead to ventricular arrhythmias. In particular, we sought to determine whether sodium (Na+) current loss-of-function in the structurally normal ventricles provides a substrate for unidirectional conduction block and reentry initiated by SCR-mediated PVCs. To achieve this goal, a stochastic model of SCR was incorporated into an anatomically accurate compute model of the rabbit ventricles with the His-Purkinje system (HPS). Simulations with reduced Na+ current due to a negative-shift in the steady-state channel inactivation showed that SCR-mediated delayed afterdepolarizations led to PVC formation in the HPS, where the electrotonic load was lower, conduction block, and reentry in the 3D myocardium. Moreover, arrhythmia initiation was only possible when intrinsic electrophysiological heterogeneity in action potential within the ventricles was present. In conclusion, while benign in healthy individuals SCR-mediated PVCs can lead to life-threatening ventricular arrhythmias when combined with Na+ channelopathies.
An inexact two-stage stochastic risk-aversion model for integrated energy system management in Beijing-Tianjin-Hebei, China
Authors: Wang Bin , Zhang Xinxin , Li Xin , Jiang ZeYi , Xie Yulei
Published: August 2017

An inexact two-stage stochastic risk-aversion model was developed in this study for supporting regional energy system planning and management. It can tackle uncertainties described in terms of probability distributions and permits the in-depth analysis of various policy scenarios when the promised policy targets are violated. Moreover, it can help local decision-makers evaluate trade-offs between energy system economy and stability associated with different robust criteria (risk-aversion levels). An actual case study in the Beijing-Tianjin-Hebei (BTH) region, China, was provided for demonstrating the applicability of the developed model. The results indicated that electricity generated by coal-burning (coal-fired power and coal-fired cogeneration) and gas-fired heating would be the main power forms for power and heat supply to get the maximum security. Furthermore, some policy implications can be concluded as follows: (a) more attention should be focused on increasing the local power generation capacity in the BTH region rather than importing electricity from other regions; (b) the introduction of risk aversion into the optimization model is conducive to the development of solar power, biomass power, and gas-fired cogeneration; and (c) renewable energy (e.g., biomass energy and geothermal energy) development in the BTH region still has a long way to go, because it is constrained by resource endowment and geographical location. Generally, the proposed model not only can help decision-makers identify the desired energy system management policies under risk considerations, but also could be viewed as a prime example for energy system planning and management at different regional levels (e.g., city, province, and multiprovince) and used as a reference for energy structure adjustment in other metropolitan groups such as the Yangtze River Delta and Pearl River Delta urban agglomerations.
Direct loop gain and bandwidth measurement of phase-locked loop
Authors: Ye P. , Ren R. , Kou Y. , Sun F. , Hu J. , Chen S. , Hou D.
Published: August 2017

A simple and robust technique for directly measuring the loop gain and bandwidth of a phase-locked loop (PLL) is proposed. This technique can be used for the real-time measurement of the real loop gain in a closed PLL without breaking its locking state. The agreement of the measured loop gain and theoretical calculations proves the validity of the proposed measurement technique. This technique with a simple configuration can be easily expanded to other phase-locking systems whose loop gain and bandwidth should be measured precisely.
Room-temperature capsule-shaped wavelength-scale metal-clad laser with enhanced side mode suppression
Authors: Xiao Yi , Taylor Richard J. E. , Yu Chuanqing , Feng Kaiyin , Tanemura Takuo , Nakano Yoshiaki
Published: August 2017

We fabricate a capsule-shaped metal-clad wavelength-scale InP/InGaAs cavity and demonstrate room-temperature lasing at a wavelength of ∼1550 nm under pulsed optical pumping. By introducing an optimized curvature to the sidewalls of a conventional rectangular metal-clad laser, we effectively reduce the metallic loss of the transverse-electric mode and experimentally confirm a clear improvement in the side mode suppression ratio and slope efficiency.
Understanding the role of tilt-curvature coupling in lipid membrane elasticity
Authors: Hendricks-Sturrup Rachele
Published: August 2017

Carnegie Mellon researchers correct a 3d continuum elasticity Hamiltonian using a novel tilt-curvature coupling to more accurately describe lipid membrane elasticity.
Electrically tuning reflection of graphene-based Tamm plasmon polariton structures at 1550 nm
Authors: Li Liang , Zhao Hua , Zhang Jingwen
Published: August 2017

Tunable reflection of graphene-based Tamm plasmon polariton structures was theoretically investigated at 1550 nm. The graphene, inserted between the metal film and the Bragg mirror, is modulated by electron injection through applying an external electric field. Our results show that the reflection spectrum of the structure has a narrow valley near 1550 nm. Moreover, the valley depth can be highly tuned by the applied electric field. In addition, we find that the valley depth is also affected by the number of the Bragg mirror's period and the distance between the metal film and the graphene. Importantly, the valley depth near 1550 nm can be continuously tuned from ∼0.38 to ∼0.99 under suitable conditions.
New exploration opportunities on the southwest Australian margin—deep-water frontier Mentelle Basin
Authors: Borissova Irina , Bradshaw Barry , Nicholson Chris , Struckmeyer Heike , Payne Danielle
Published: August 2017

Acreage release by the Australian Government in 2010 offers exploration opportunities in the frontier Mentelle Basin for the first time. The Mentelle Basin is a large deep-water basin on the southwest Australian margin. It consists of a large, very deep water (2,000—4,000 m) depocentre in the west and several depocentres in the east, in water depths of 500–2,000 m. The major depocentres are estimated to contain 7–11 km of sediments.
Initial rifting in the Mentelle Basin occurred in the Early Permian, followed by thermal subsidence during the Triassic to Early Jurassic. In the Middle Jurassic renewed extension led to the accumulation of very thick sedimentary successions in half-graben depocentres. Early Cretaceous continental breakup was accompanied by extensive volcanism resulting in a thick syn-breakup volcanic succession in the western Mentelle Basin.
Assessment of the petroleum prospectivity of the Mentelle Basin is based on correlations with the adjacent Vlaming Sub-basin. These correlations suggest that the Mentelle Basin depocentres are likely to contain multiple source rock intervals associated with coals and carbonaceous shales, as well as regionally extensive reservoirs and seals within fluvial, lacustrine and marine strata. Petroleum systems modelling suggests that potential source rocks are thermally mature and commenced generation in the Early Cretaceous. The Mentelle Basin offers a wide range of play types, including faulted anticlines and fault blocks, sub-basalt anticlines and fault blocks, drape and forced fold plays, and a large range of stratigraphic and unconformity plays.
Greenhouse gas storage and its impacts on the upstream petroleum and gas industry
Authors: Cansdale Ben , McSweeney Jodie
Published: August 2017

Is the reservoir half full or half empty? Both scenarios are one for the optimist depending on whether that optimist is a petroleum producer, or a greenhouse gas storage provider.
As Australia looks towards greenhouse gas storage as an important option for reducing carbon dioxide emissions, greenhouse gas storage may herald the emergence of an entirely new industry. This new industry will have far-reaching impacts across a broad spectrum of existing industries, not least of which is the upstream petroleum and gas industry.
In this time of increasing demand for gas, not only will competition for the same geological spaces remain rife among petroleum and gas producers, but greenhouse gas storage providers may seek these very same spaces for their own operations. Other points of contention between the industries could include concurrent land use on overlapping tenures and the development, operation and ownership of pipelines.
Petroleum and gas industry participants will need to adapt to the new challenges arising from the emergence of greenhouse gas storage. And if petroleum and gas producers decide to take up some of the opportunities offered by the new industry, they will need to grapple with significant questions about feasibility and risk associated with greenhouse gas storage projects inherent in the legislative regimes enacted to date.
Using Queensland’s new Greenhouse Gas Storage Act 2009 as a platform, Ben Cansdale will examine these challenges and discuss the potential impact a greenhouse gas storage industry will have for Australia’s petroleum and gas industries.
Magnetic tensor gradiometry and marine CSEM
Authors: Annetts David
Published: August 2017

In recent times, surveys employing tensor gradiometers have been used in mineral exploration. Some reasons for this are potential advantages such as improved resolution, data interpolation, noise suppression and relative insensitivity to survey orientation. The last two potentialities are particularly germane to marine CSEM surveys, which are typically sparsely sampled and require processing of measured fields to ensure that the correct vector component is analysed.
In a series of numerical modelling studies of typical frequency-domain CSEM surveys in both shallow and deep water columns, this paper shows that tensor gradient measurements have advantages over conventional CSEM measurements in terms of target definition, especially when survey lines do not fall over target centres.
Stochastic forecasting of production potential using customised type curves in coal seam gas
Authors: Zangl Georg , Biniwale Shripad , Al-Kinani Andreas , Sharma Vikram , Trivedi Rajesh
Published: August 2017

This paper discusses a new workflow to stochastically estimate the performance of future production in coal seam gas (CSG) developments. Usually performance evaluations for CSG wells are conducted using either much-generalised statistical methods or numerical simulation. Both approaches have significant drawbacks; the former methods are quick but very often lack accuracy, while the latter is very accurate however also usually highly complex in set-up and computation.
The presented workflow is a new approach to well performance prediction that combines speed and reasonable accuracy. The workflow generates a set of key performance indicators of existing wells derived from historic dynamic data (water and gas production rates, pressures, etc.), static data (initial coal and reservoir properties, etc.) and predicted data (simplified production forecasts). The wells are then grouped according to the similarity of their KPIs. The production profiles of the wells within the same group are combined to a type curve that is described by the most likely production profile and an associated uncertainty range.
A data-driven expert system is used to identify and capture the correlations of the parameters such as geographic locations, well spacing, reservoir properties and the group membership (equivalent to type curve). This expert system can then be applied to any location in the field in order to determine the most likely group membership of a potential well. The classification of a new well to a group is hereby not necessarily unique; the expert system might classify a new well into several groups and assign a probability of occurrence for each of the groups. A Monte Carlo routine is then applied to forecast the performance of the new well locations honoring the respective probability of occurrence of each type curve.