bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi‐physics modelling approach for investigation of moisture dynamics in power transformers
Authors: Cui Yi , Ma Hui , Saha Tapan , Ekanayake Chandima , Wu Guangning
Published: March 2016

The presence of moisture in a power transformer is harmful to its oil–cellulose system and can also accelerate the ageing. Therefore, it is necessary to estimate the moisture content inside the transformer. Due to the variation of loading conditions and ambient temperatures, moisture is neither in a static state nor uniformly distributed in transformers. Moisture migrates between oil and cellulose and moves inside oil and cellulose of transformers. Moreover, given the complexity of a transformer's structure, moisture distribution is also a function of mass and dimensions of transformer's oil–cellulose system. This study adopts a multi‐physics modelling approach to investigate moisture dynamics in transformers. In this approach, moisture dynamics is investigated by coupling electromagnetic, thermal, fluid flow and moisture migration physics simultaneously. An accurate estimation on moisture distribution in transformers can then be obtained. Extensive ageing and moisture diffusion experiments have been conducted on a prototype transformer to verify the proposed approach.
On‐line recursive method of phasor and frequency estimation for power system monitoring and relaying
Authors: Ashrafian Abdolaziz , Mirsalim Mojtaba
Published: March 2016

A real‐time method of phasor and frequency estimation is proposed in this study. The method is based on the recently developed signal processing tool, S‐transform. It is implemented recursively by taking advantage of recursive complex band pass infinite impulse response filters with a low computational burden, using only 10 samples of the previous output and nine samples of the input signal. The method is implemented in the Matlab software and its performance is appraised considering the decaying DC component, noise and severe harmonic and inter‐harmonic distortions and dynamic conditions. Moreover, a wavelet based method, a discrete Fourier and a recursive discrete Fourier based method for phasor estimation have been implemented and the performances of the methods have been compared in various operating conditions. To assess methods performances for real signals, the recorded signals of a differential relay have been fed to all of the methods and their performances compared. In addition, a power system has been simulated in the EMTP software, and performances of the methods have been assessed using the recorded fault signals of the EMTP software. Both the real data and simulation results indicate that the proposed S‐transform based method is superior to other methods considering dynamic and static conditions.
Real‐time video chroma keying: a parallel approach based on local texture and global colour distribution
Authors: Yin Ling , Wang Wenyi , Zhao Jiying
Published: March 2016

This study presents an automatic, human perception based chroma‐keying algorithm that extracts the objects of interest (i.e. foreground) from monochromatic background. Given an image to be chroma keyed, the global colour distribution and the local texture property are analysed in CIECAM02 colour appearance model. After the analysis, input image is automatically segmented into three parts: foreground, background, and uncertain regions. Afterwards, the background colour is propagated from known background to uncertain region by using interpolation functions; and the foreground colour is estimated based on global colour distribution and a linear cost criteria. The quantitative and perceptual comparisons on the matting results show that the proposed method can reliably remove the background region, correctly restore the intrinsic foreground colour, and accurately keep the fine details. In addition, the authors implement the proposed method on a heterogeneous parallel computing architecture which efficiently distributes the workload among different processors. The simulation results show that the foreground objects can be accurately extracted from high‐definition and/or ultra‐high‐definition videos in real time.
Zero‐current‐switching bidirectional interleaved switched‐capacitor DC–DC converter: analysis, design and implementation
Authors: Choi Hyuntae , Jang Minsoo , Agelidis Vassilios Georgios
Published: March 2016

The study presents experimental verification of a zero‐current‐switching (ZCS) bidirectional interleaved switched‐capacitor (BISC) DC–DC converter that features bidirectional power flow capability and a high‐voltage conversion ratio. In addition, the interleaved configuration of the converter and its modular design enable both its current rating and voltage gain to be increased. At the same time, the converter does not exhibit current spike issues, which is achieved by employing stray inductance distributed throughout the circuit, rather than relying on an additional magnetic‐core inductor. Moreover, the ZCS operation of the converter improves the converter efficiency. The operating principle and theoretical analysis of the BISC converter under both forward and reverse modes are presented in detail. Simulation and experimental results from a 1.5 kW prototype validate the operation and characteristics of the BISC DC–DC converter.
Galvanically isolated high gain Y‐source DC–DC converters for dispersed power generation
Authors: Forouzesh Mojtaba , Baghramian Alfred
Published: March 2016

This study deals with a novel high voltage gain isolated dc–dc converter that utilise a versatile Y‐source for its boosting stage. Having Y‐source impedance network, isolation transformer and voltage doubling rectifier, the proposed converter can achieve high voltage gain with reduced stress on its components. Since continuous input current (CIC) ability is an advantageous characteristic of dc–dc converters tied to renewable energy sources, a CIC version of the proposed converter is well demonstrated and discussed in the study. In addition, detailed operation principles of the proposed converters are mathematically expressed. Simulation results from Simulink\Pspice interface have examined the performance of proposed converters in both boost and normal operation modes. Finally, a laboratory prototype was built to evaluate the theoretical assumptions. Besides, in the experiment a TMS320F2812 digital signal processor board was used for generating the shifted shoot‐through control method. Experimental results in both operation modes show a reliable performance for the proposed CIC converter and its counterpart.
Multi‐terminal HVDC grids with inertia mimicry capability
Authors: Zhang Weiyi , Rouzbehi Kumars , Luna Alvaro , Gharehpetian Gevork B. , Rodriguez Pedro
Published: March 2016

The high‐voltage multi‐terminal dc (MTDC) systems are foreseen to experience an important development in the next years. Currently, they have appeared to be a prevailing technical and economical solution for harvesting offshore wind energy. In this study, inertia mimicry capability is added to a voltage‐source converter‐HVDC grid‐side station in an MTDC grid connected to a weak ac grid, which can have low inertia or even operate as an islanded grid. The presented inertia mimicry control is integrated in the generalised voltage droop strategy implemented at the primary level of a two‐layer hierarchical control structure of the MTDC grid to provide higher flexibility, and thus controllability to the network. Besides, complete control framework from the operational point of view is developed to integrate the low‐level control of the converter stations in the supervisory control centre of the MTDC grid. A scaled laboratory test results considering the international council on large electric systems (CIGRE) B4 MTDC grid demonstrate the good performance of the converter station when it is connected to a weak islanded ac grid.
Use of smart‐meter data to determine distribution system topology
Authors: Watson Jeremy Donald , Welch John , Watson Neville R.
Published: March 2016

Smart‐meter data presents an opportunity for utilities to improve their database records, and develop a low‐voltage (LV) model which may be useful for outage management and fault detection, isolation and response, phase balancing, and network planning. In addition, impact assessment studies on new technologies can be performed. This study presents several contributions in the area of determining the topology of the LV distribution system. This is in terms of identifying the transformer a particular installation control point is connected to, and the phase if that customer is single‐phase. First, harmonic voltage correlation is proposed as it is more robust to noise and missing records than the prior algorithm of voltage correlation. Second, it is demonstrated that smart‐meter data can be used to determine the transformer/phase to which a customer is connected and update database records in this regard. To achieve this, a new algorithm based on correlation analysis with the Fisher Z transform is developed. Third, a method to estimate LV feeder and service main impedances is presented. Further work is necessary; however, the results from trials in Auckland, New Zealand are highly promising.
Umsetzung Betrieblicher Gesundheitsförderung/Betrieblichen Gesundheitsmanagements in Deutschland: Stand und Entwicklungsbedarfe der einschlägigen Forschung
Authors: Faller G.
Published: March 2016

Ziel der Studie: Zur Frage der Verbreitung von Gesundheitsförderung/Gesundheitsmanagement in deutschen Betrieben liegen heterogene Ergebnisse vor. Das Ziel der Studie besteht darin, mehr Transparenz über die Ursachen dieser Diskrepanzen sowie zu möglichen Einflussfaktoren auf die Bereitschaft zur Umsetzung von BGF/BGM zu gewinnen.

Methodik: Auf Basis einer systematischen Datenbankrecherche wurden einschlägige Studien identifiziert und einer vergleichenden inhaltlichen Analyse unterzogen.

Ergebnisse: Die Studien zur Verbreitung von BGF/BGM in Deutschland weisen hinsichtlich Fragestellung, Repräsentativität, Vorgehen und Design erhebliche Unterschiede auf. Dennoch zeichnen sich übereinstimmende Tendenzen hinsichtlich der Identifikation signifikanter Einflussfaktoren auf die Bereitschaft zur Umsetzung von BGF/BGM ab.

Schlussfolgerungen: Bei der Konzeption künftiger Studien zur Analyse der Verbreitung von BGF/BGM ist es wichtig, sich auf eine einheitliche Definition sowie ein vergleichbares Erfassungs- und Kategorisierungsschema der erhobenen Maßnahmen zu einigen. Im Hinblick auf die Auswertung von Auswirkungen der betrieblichen Interventionen wären die quantitativen durch qualitative Daten zu ergänzen, die in der Lage sind, das „Wie“ der Umsetzung sowie darauf bezogene, spezifische organisationskulturelle Deutungsmuster zu erfassen.
Stochastic responses of Van der Pol vibro-impact system with fractional derivative damping excited by Gaussian white noise
Authors: Xiao Yanwen , Xu Wei , Wang Liang
Published: March 2016

This paper focuses on the study of the stochastic Van der Pol vibro-impact system with fractional derivative damping under Gaussian white noise excitation. The equations of the original system are simplified by non-smooth transformation. For the simplified equation, the stochastic averaging approach is applied to solve it. Then, the fractional derivative damping term is facilitated by a numerical scheme, therewith the fourth-order Runge-Kutta method is used to obtain the numerical results. And the numerical simulation results fit the analytical solutions. Therefore, the proposed analytical means to study this system are proved to be feasible. In this context, the effects on the response stationary probability density functions (PDFs) caused by noise excitation, restitution condition, and fractional derivative damping are considered, in addition the stochastic P-bifurcation is also explored in this paper through varying the value of the coefficient of fractional derivative damping and the restitution coefficient. These system parameters not only influence the response PDFs of this system but also can cause the stochastic P-bifurcation.
Using heteroclinic orbits to quantify topological entropy in fluid flows
Authors: Sattari Sulimon , Chen Qianting , Mitchell Kevin A.
Published: March 2016

Topological approaches to mixing are important tools to understand chaotic fluid flows, ranging from oceanic transport to the design of micro-mixers. Typically, topological entropy, the exponential growth rate of material lines, is used to quantify topological mixing. Computing topological entropy from the direct stretching rate is computationally expensive and sheds little light on the source of the mixing. Earlier approaches emphasized that topological entropy could be viewed as generated by the braiding of virtual, or “ghost,” rods stirring the fluid in a periodic manner. Here, we demonstrate that topological entropy can also be viewed as generated by the braiding of ghost rods following heteroclinic orbits instead. We use the machinery of homotopic lobe dynamics, which extracts symbolic dynamics from finite-length pieces of stable and unstable manifolds attached to fixed points of the fluid flow. As an example, we focus on the topological entropy of a bounded, chaotic, two-dimensional, double-vortex cavity flow. Over a certain parameter range, the topological entropy is primarily due to the braiding of a period-three orbit. However, this orbit does not explain the topological entropy for parameter values where it does not exist, nor does it explain the excess of topological entropy for the entire range of its existence. We show that braiding by heteroclinic orbits provides an accurate computation of topological entropy when the period-three orbit does not exist, and that it provides an explanation for some of the excess topological entropy when the period-three orbit does exist. Furthermore, the computation of symbolic dynamics using heteroclinic orbits has been automated and can be used to compute topological entropy for a general 2D fluid flow.
High pressure structural changes in aluminium triiodide: A first principles study
Authors: Majumdar Arnab , Klug Dennis D. , Yao Yansun
Published: March 2016

First principles calculations identified a phase transition in aluminium triiodide (AlI3) and predicted its physical and spectroscopic properties under high pressure conditions. A high pressure monoclinic phase is predicted to exist above 1.3 GPa accompanied with a coordination change of aluminium resulting from a transformation from the ambient pressure 4-coordinated primitive monoclinic phase with space group P21/c to the monoclinic 6-coordinated structure with space group C2/m. Density functional phonon calculations predicted its dynamical and mechanical stability. Infrared effective charge intensities and Raman scattering tensors were obtained to characterize its spectroscopic properties. First-principles metadynamics simulations were employed to reconstruct this phase transition and provide the mechanism details for energetically favourable path from the ambient pressure P21/c structure to the predicted C2/m structure.
Dynamic response in a finite size composite multiferroic thin film
Authors: Wang Zidong , Grimson Malcolm J.
Published: March 2016

Composite multiferroics, heterostructures of ferromagnetic and ferroelectric materials, are characterized by a remarkable magnetoelectric effect at the interface. Previous work has supported the ferromagnetic structure with magnetic spins and the ferroelectric with pseudospins which act as electric dipoles in a microscopic model, coupled with a magnetoelectric interaction [Wang and Grimson, J. Appl. Phys. 118, 124109 (2015)]. In this work, by solving the stochastic Landau-Lifshitz-Gilbert equation, the electric-field-induced magnetization switching in a twisted boundary condition has been studied, and a behavior of domain wall in the ferromagnetic structure is discussed.
Investigation on onset voltage and conduction channel temperature in voltage-induced metal-insulator transition of vanadium dioxide
Authors: Yoon Joonseok , Kim Howon , Mun Bongjin Simon , Park Changwoo , Ju Honglyoul
Published: March 2016

The characteristics of onset voltages and conduction channel temperatures in the metal-insulator transition (MIT) of vanadium dioxide (VO2) devices are investigated as a function of dimensions and ambient temperature. The MIT onset voltage varies from 18 V to 199 V as the device length increases from 5 to 80 μm at a fixed width of 100 μm. The estimated temperature at local conduction channel increases from 110 to 370 °C, which is higher than the MIT temperature (67 °C) of VO2. A simple Joule-heating model is employed to explain voltage-induced MIT as well as to estimate temperatures of conduction channel appearing after MIT in various-sized devices. Our findings on VO2 can be applied to micro- to nano-size tunable heating devices, e.g., microscale scanning thermal cantilevers and gas sensors.
On the convergence of quantum resonant-state expansion
Authors: Brown J. M. , Jakobsen P. , Bahl A. , Moloney J. V. , Kolesik M.
Published: March 2016

Completeness of the system of Stark resonant states is investigated for a one-dimensional quantum particle with the Dirac-delta potential exposed to an external homogeneous field. It is shown that the resonant series representation of a given wavefunction converges on the negative real axis while the series diverges on the positive axis. Despite the divergent nature of the resonant expansion, good approximations can be obtained in a compact spatial domain.
Nonlinear low frequency electrostatic structures in a magnetized two-component auroral plasma
Authors: Rufai O. R. , Bharuthram R. , Singh S. V. , Lakhina G. S.
Published: March 2016

Finite amplitude nonlinear ion-acoustic solitons, double layers, and supersolitons in a magnetized two-component plasma composed of adiabatic warm ions fluid and energetic nonthermal electrons are studied by employing the Sagdeev pseudopotential technique and assuming the charge neutrality condition at equilibrium. The model generates supersoliton structures at supersonic Mach numbers regime in addition to solitons and double layers, whereas in the unmagnetized two-component plasma case only, soliton and double layer solutions can be obtained. Further investigation revealed that wave obliqueness plays a critical role for the evolution of supersoliton structures in magnetized two-component plasmas. In addition, the effect of ion temperature and nonthermal energetic electron tends to decrease the speed of oscillation of the nonlinear electrostatic structures. The present theoretical results are compared with Viking satellite observations.
Effect of plasma parameters on characteristics of silicon nitride film deposited by single and dual frequency plasma enhanced chemical vapor deposition
Authors: Sahu B. B. , Yin Yongyi , Han Jeon G.
Published: March 2016

This work investigates the deposition of hydrogenated amorphous silicon nitride films using various low-temperature plasmas. Utilizing radio-frequency (RF, 13.56 MHz) and ultra-high frequency (UHF, 320 MHz) powers, different plasma enhanced chemical vapor deposition processes are conducted in the mixture of reactive N2/NH3/SiH4 gases. The processes are extensively characterized using different plasma diagnostic tools to study their plasma and radical generation capabilities. A typical transition of the electron energy distribution function from single- to bi-Maxwellian type is achieved by combining RF and ultra-high powers. Data analysis revealed that the RF/UHF dual frequency power enhances the plasma surface heating and produces hot electron population with relatively low electron temperature and high plasma density. Using various film analysis methods, we have investigated the role of plasma parameters on the compositional, structural, and optical properties of the deposited films to optimize the process conditions. The presented results show that the dual frequency power is effective for enhancing dissociation and ionization of neutrals, which in turn helps in enabling high deposition rate and improving film properties.
Time evolution of the electron energy distribution function in pulsed microwave magnetoplasma in H2
Authors: Jauberteau J. L. , Jauberteau I. , Cortázar O. D. , Megía-Macías A.
Published: March 2016

Time evolution of the Electron Energy Distribution Function (EEDF) is measured in pulsed hydrogen microwave magnetoplasma working at 2.45 GHz. Analysis is performed both in resonance (B = 0.087 T) and off-resonance conditions (B = 0.120 T), at two pressures (0.38 Pa and 0.62 Pa), respectively, and for different incident microwave powers. The important effect of the magnetic field on the electron kinetic is discussed, and a critical analysis of Langmuir probe measurements is given. The Electron Energy Distribution Function is calculated using the Druyvesteyn theory (EEDF) and is corrected using the theory developed by Arslanbekov in the case of magnetized plasma. Three different components are observed in the EEDF, whatever the theory used. They are: (a) a low electron energy component at energy lower than 10 eV, which is ascribed to the electron having inelastic collisions with heavy species (H2, H, ions), (b) a high energy component with a mean energy ranging from 10 to 20 eV, which is generally ascribed to the heating of the plasma by the incident microwave power, and (c) a third component observed between the two other ones, mainly at low pressure and in resonance conditions, has been correlated to the electron rotation in the magnetic field.
Communication: Nanoscale structure of tetradecyltrihexylphosphonium based ionic liquids
Authors: Hettige Jeevapani J. , Araque Juan C. , Kashyap Hemant K. , Margulis Claudio J.
Published: March 2016

In a recent communication [J. J. Hettige et al., J. Chem. Phys. 140, 111102 (2014)], we investigated the anomalous temperature dependence of the X-ray first sharp diffraction peak (or prepeak) in the tetradecyltrihexylphosphonium bis(trifluoromethylsulfonyl)-amide ionic liquid. Contrary to what was expected and often observed, the first sharp diffraction peak in this system was shown to increase in intensity with increasing temperature. This implies higher intermediate-range periodicity at a higher temperature. Is this counter-intuitive behavior specific to the combination of cation and anion? The current work analyzes the structural behavior of the same cation coupled with six different anions ranging from the small and spherically symmetric Cl− to the more structurally complex and charge-diffuse NTf2−. In all cases, the same temperature behavior trend for the prepeak is observed independent of anionic nature. We will show that the intensity increase in the prepeak region is associated with the structural behavior of charged liquid subcomponents. Instead, upon a temperature increase, the apolar subcomponents contribute to what would be an expected decrease of prepeak intensity.
Enhanced thermoelectric performance of graphene nanoribbon-based devices
Authors: Hossain Md Sharafat , Huynh Duc Hau , Nguyen Phuong Duc , Jiang Liming , Nguyen Thanh Cong , Al-Dirini Feras , Hossain Faruque M. , Skafidas Efstratios
Published: March 2016

There have been numerous theoretical studies on exciting thermoelectric properties of graphene nano-ribbons (GNRs); however, most of these studies are mainly based on simulations. In this work, we measure and characterize the thermoelectric properties of GNRs and compare the results with theoretical predictions. Our experimental results verify that nano-structuring and patterning graphene into nano-ribbons significantly enhance its thermoelectric power, confirming previous predictions. Although patterning results in lower conductance (G), the overall power factor (S2G) increases for nanoribbons. We demonstrate that edge roughness plays an important role in achieving such an enhanced performance and support it through first principles simulations. We show that uncontrolled edge roughness, which is considered detrimental in GNR-based electronic devices, leads to enhanced thermoelectric performance of GNR-based thermoelectric devices. The result validates previously reported theoretical studies of GNRs and demonstrates the potential of GNRs for the realization of highly efficient thermoelectric devices.
Enhancement of thermoelectric properties by energy filtering: Theoretical potential and experimental reality in nanostructured ZnSb
Authors: Berland Kristian , Song Xin , Carvalho Patricia A. , Persson Clas , Finstad Terje G. , Løvvik Ole Martin
Published: March 2016

Energy filtering has been suggested by many authors as a means to improve thermoelectric properties. The idea is to filter away low-energy charge carriers in order to increase Seebeck coefficient without compromising electronic conductivity. This concept was investigated in the present paper for a specific material (ZnSb) by a combination of first-principles atomic-scale calculations, Boltzmann transport theory, and experimental studies of the same system. The potential of filtering in this material was first quantified, and it was as an example found that the power factor could be enhanced by an order of magnitude when the filter barrier height was 0.5 eV. Measured values of the Hall carrier concentration in bulk ZnSb were then used to calibrate the transport calculations, and nanostructured ZnSb with average grain size around 70 nm was processed to achieve filtering as suggested previously in the literature. Various scattering mechanisms were employed in the transport calculations and compared with the measured transport properties in nanostructured ZnSb as a function of temperature. Reasonable correspondence between theory and experiment could be achieved when a combination of constant lifetime scattering and energy filtering with a 0.25 eV barrier was employed. However, the difference between bulk and nanostructured samples was not sufficient to justify the introduction of an energy filtering mechanism. The reasons for this and possibilities to achieve filtering were discussed in the paper.
Observation of spontaneous combustion of hydrogen and oxygen in microbubbles
Authors: Postnikov A. V. , Uvarov I. V. , Prokaznikov A. V. , Svetovoy V. B.
Published: March 2016

Experimental evidence is presented that combustion can ignite at room temperature spontaneously inside microbubbles filled with mixture of hydrogen and oxygen. We perform water electrolysis in a closed microchamber by voltage pulses of alternating polarity at repetition frequencies ≥100 kHz to pump the gases rapidly into the electrolyte and produce extreme supersaturation with both gases. After a delay of 300−600 μs, we observe stroboscopically microbubbles of 5−20 μm in diameter that appear in between the electrodes for several microseconds. Each event is accompanied by a pressure jump of 0.1−1 bar that is measured interferometrically. The pressure jumps are attributed to combustion of the gases in the microbubbles.
Intrinsic emittance reduction in transmission mode photocathodes
Authors: Lee Hyeri , Cultrera Luca , Bazarov Ivan
Published: March 2016

High quantum efficiency (QE) and low emittance electron beams provided by multi-alkali photocathodes make them of great interest for next generation high brightness photoinjectors. Spicer's three-step model well describes the photoemission process; however, some photocathode characteristics such as their thickness have not yet been completely exploited to further improve the brightness of the generated electron beams. In this work, we report on the emittance and QE of a multi-alkali photocathode grown onto a glass substrate operated in transmission and reflection modes at different photon energies. We observed a 20% reduction in the intrinsic emittance from the reflection to the transmission mode operation. This observation can be explained by inelastic electron-phonon scattering during electrons' transit towards the cathode surface. Due to this effect, we predict that thicker photocathode layers will further reduce the intrinsic emittance of electron beams generated by photocathodes operated in transmission mode.
Pressure-driven amplification and penetration of resonant magnetic perturbations
Authors: Loizu J. , Hudson S. R. , Helander P. , Lazerson S. A. , Bhattacharjee A.
Published: March 2016

We show that a resonant magnetic perturbation applied to the boundary of an ideal plasma screw-pinch equilibrium with nested surfaces can penetrate inside the resonant surface and into the core. The response is significantly amplified with increasing plasma pressure. We present a rigorous verification of nonlinear equilibrium codes against linear theory, showing excellent agreement.
Interaction of plasma-generated water cluster ions with chemically-modified Si surfaces investigated by infrared absorption spectroscopy
Authors: Hirano-Iwata Ayumi , Matsumura Ryosuke , Ma Teng , Kimura Yasuo , Niwano Michio , Nishikawa Kazuo
Published: March 2016

We have investigated the interaction of water cluster ions generated by discharge plasma, with chemically modified Si surfaces using infrared absorption spectroscopy in the multiple internal reflection geometry. We observe that water cluster ions readily adsorb on SiO2-covered Si surfaces to form water droplets. We demonstrate that positively- and negatively-charged cluster ions adsorb on the SiO2-covered Si surface in different manners, indicating ionic interaction of the water droplets with the negatively-charged SiO2 surface. Water droplets formed on the protein-coated surface rupture the amide bond of the proteins, suggesting the function of protein decomposition of water cluster ions.
Correlation between surface modification and photoluminescence properties of β-Ga2O3 nanostructures
Authors: Jangir R. , Porwal S. , Tiwari Pragya , Mondal Puspen , Rai S. K. , Srivastava A. K. , Bhaumik Indranil , Ganguli Tapas
Published: March 2016

In this work three different growth methods have been used to grow β-Ga2O3 nanostructures. The nanostructures were characterized by Grazing Incident X-Ray Diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy and Photoluminescence Spectroscopy. Photoluminescence spectra for all the samples of β-Ga2O3 nanostructures exhibit an UV and blue emission band. The relative intensity of UV and blue luminescence is strongly affected by the surface defects present on the nanostructures. Our study shows that Photoluminescence intensity of UV and blue luminescence can be reliably used to determine the quality of β-Ga2O3 nanostructures. Further the work opens up the possibility of using UV excitation and subsequent Photoluminescence analysis as a possible means for oxygen sensing. The Photoluminescence mechanism in β-Ga2O3 nanostructures is also discussed.
Ferroelectric properties of lead-free polycrystalline CaBi2Nb2O9 thin films on glass substrates
Authors: Ahn Yoonho , Jang Joonkyung , Son Jong Yeog
Published: March 2016

CaBi2Nb2O9 (CBNO) thin film, a lead-free ferroelectric material, was prepared on a Pt/Ta/glass substrate via pulsed laser deposition. The Ta film was deposited on the glass substrate for a buffer layer. A (115) preferred orientation of the polycrystalline CBNO thin film was verified via X-ray diffraction measurements. The CBNO thin film on a glass substrate exhibited good ferroelectric properties with a remnant polarization of 4.8 μC/cm2 (2Pr ∼9.6 μC/cm2), although it had lower polarization than the epitaxially c-oriented CBNO thin film reported previously. A mosaic-like ferroelectric domain structure was observed via piezoresponse force microscopy. Significantly, the polycrystalline CBNO thin film showed much faster switching behavior within about 100 ns than that of the epitaxially c-oriented CBNO thin film.
Photoelectron Spectroscopy and Density Functional Calculations of TiGen− (n=7–12) Clusters
Authors: Deng Xiao-jiao , Kong Xiang-yu , Xu Xi-ling , Xu Hong-guang , Zheng Wei-jun
Published: March 2016

The growth pattern and electronic properties of TiGen− (n=7–12) clusters were investigated using anion photoelectron spectroscopy and density functional theory calculations. For both anionic and neutral TiGen clusters, a half-encapsulated boat-shaped structure appears at n=8, and the boat-shaped structure is gradually covered by the additional Ge atoms to form Gen cage at n=9–11. TiGe12− cluster has a distorted hexagonal prism cage structure. According to the natural population analysis, the electron transfers from the Gen framework to the Ti atom for TiGen−/0 clusters at n=8–12, implying that the electron transfer pattern is related to the structural evolution.
Reducing variation in pork production systems through maternal and pre- and post-weaning nutrition strategies
Authors: van Barneveld R. J. , Hewitt R. J. E.
Published: March 2016

Variation is inherent in any biological system and is a challenge to manage in modern pork-production businesses. In the case of the growing and finishing herd, inherent variation within a population of pigs represents a significant cost as a result of the need to select on farm to meet market specifications, poor matching of diet specifications to nutrient requirements, grading losses, higher pre-weaning mortality, and challenges associated with health management. As a consequence, any management practice that can be applied to reduce variation at the point of sale has the potential to improve the profitability and overall efficiency of a pig enterprise. The present paper considers nutritional interventions of sows during gestation, lactation and the weaning to oestrus interval to minimise inherent variation in the progeny and then pre- and post-weaning nutrition of piglets to limit further variation. Prior to birth, there are many factors that can influence variation in the birthweight and growth potential of the progeny. In gestating sows, dietary energy will not influence variation in birthweight, but supplementation with free arginine and glutamine will reduce variation in birthweight of piglets born and piglets born alive. In lactating sows, maintenance of feed intake to optimise milk production and minimise weight loss of the sow during lactation not only minimises variation in progeny weight at weaning, but enhances subsequent birthweight heterogeneity due to the influence of the sow’s metabolic status on follicle and oocyte quality. Supplementation with dextrose during the weaning to oestrus interval can also reduce variation in birthweight due to a pronounced effect on plasma glucose and insulin concentrations. Prior to weaning, light weight piglets appear to have an enhanced capacity for growth compared with their larger counterparts. To this end, split suckling has been shown to reduce weaning-weight variation, despite no effect on average growth rate or weaning weight for litters with nine piglets or more born alive. Supplemental milk before weaning has reduced variation in weaning weights, but creep feeding has proved equivocal in this regard. Post-weaning, it appears that remedial feeding strategies will do little to improve the growth potential of light-weight pigs, and while high specification diets may contribute to a slight reduction in variation at slaughter, this strategy is unlikely to be economically viable. As with many aspects of commercial pork production, it would seem that the greatest potential to reduce variation in the slaughter weight of market pigs vests with careful management of gestating and lactating sows, with some potential for dietary interventions to further reduce variation in birth and weaning weights.
Predictive ability of Random Forests, Boosting, Support Vector Machines and Genomic Best Linear Unbiased Prediction in different scenarios of genomic evaluation
Authors: Ghafouri-Kesbi Farhad , Rahimi-Mianji Ghodratollah , Honarvar Mahmood , Nejati-Javaremi Ardeshir
Published: March 2016

Three machine learning algorithms: Random Forests (RF), Boosting and Support Vector Machines (SVM) as well as Genomic Best Linear Unbiased Prediction (GBLUP) were used to predict genomic breeding values (GBV) and their predictive performance was compared in different combinations of heritability (0.1, 0.3, and 0.5), number of quantitative trait loci (QTL) (100, 1000) and distribution of QTL effects (normal, uniform and gamma). To this end, a genome comprised of five chromosomes, one Morgan each, was simulated on which 10000 bi-allelic single nucleotide polymorphisms were distributed. Pearson’s correlation between the true and predicted GBV and Mean Squared Error of GBV prediction were used, respectively, as measures of the predictive accuracy and the overall fit achieved with each method. In all methods, an increase in accuracy of prediction was seen following increase in heritability and decrease in the number of QTL. GBLUP had better predictive accuracy than machine learning methods in particular in the scenarios of higher number of QTL and normal and uniform distributions of QTL effects; though in most cases, the differences were non-significant. In the scenarios of small number of QTL and gamma distribution of QTL effects, Boosting outperformed other methods. Regarding Mean Squared Error of GBV prediction, in most cases Boosting outperformed other methods, although the estimates were close to that of GBLUP. Among methods studied, SVM with 0.6 gigabytes (GIG) was the most efficient user of memory followed by RF, GBLUP and Boosting with 1.2-GIG, 1.3-GIG and 2.3-GIG memory requirements, respectively. Regarding computational time, GBLUP, SVM, RF and Boosting ranked first, second, third and last with 10 min, 15 min, 75 min and 600 min, respectively. It was concluded that although stochastic gradient Boosting can predict GBV with high prediction accuracy, significantly longer computational time and memory requirement can be a serious limitation for this algorithm. Therefore, using of other variants of Boosting such as Random Boosting was recommended for genomic evaluation.
Using Landsat imagery to backcast fire and post-fire residuals in the Boreal Shield of Saskatchewan: implications for woodland caribou management
Authors: Kansas John , Vargas Javier , Skatter Hans G. , Balicki Brady , McCullum Kevin
Published: March 2016

Boreal woodland caribou (Rangifer tarandus caribou) are designated as threatened under Canada’s Species at Risk Act. A Recovery Strategy for the boreal population of caribou identified critical habitat for all but 1 of 51 caribou ranges – Saskatchewan’s Boreal Shield (SK1). The strategy identified 65% undisturbed habitat as the threshold below which a local population was not likely to be self-sustaining. Disturbance was measured as the combined effects of fires <40 years and anthropogenic land use. The fire component of the total disturbance model used fire polygons that were delineated using traditional mapping methods. Our study maps fire from 1988–2013 using the differenced Normalized Burn Ratio analysis of Landsat Thematic mapper and Operational Land Imager. Annual burned areas based on fire perimeters were similar between traditionally and Landsat-derived inventory approaches, but the traditional methods overestimated within-burn areas by 31.8%, as a result of including post-fire residuals and water bodies as burned. The federal recovery model assumes that all lands within provincial fire polygons (<40 years) are inadequate as caribou habitat, and ignores the potential value of post-fire residuals and water bodies as habitat. For some Boreal Shield ranges including SKI, where fire comprises the majority of the total disturbance and residual patches are abundant, total disturbance calculations, critical habitat designation and range planning decisions should take into account residuals, including water bodies.
Active sites and mechanisms for H
2
O
2
decomposition over Pd catalysts
Authors: Plauck Anthony , Stangland Eric E. , Dumesic James A. , Mavrikakis Manos
Published: March 2016

Significance

The use of hydrogen peroxide (H
2
O
2
) for catalytic oxidations is limited by the energy-intensive and wasteful process by which H
2
O
2
is currently produced—the anthraquinone process. The direct synthesis of H
2
O
2
(DSHP) is a promising alternative process, yet catalysts active for this reaction (Pd being the most widely studied) are generally hindered by subsequent H
2
O
2
decomposition. Through a combined theoretical and experimental approach, our work (
i
) provides an understanding of the nature of Pd active sites responsible for H
2
O
2
decomposition and (
ii
) identifies a single type of elementary step that controls the rate. These structural and mechanistic insights are important for designing improved DSHP catalysts and for developing transition-metal–catalyzed oxidations that efficiently use H
2
O
2
.
Concordance between Timeline Follow-Back and Single-Question Assessment of Self-Reported Smoking in a Clinical Trial
Authors: Bernstein Steven L. , Rosner June , Toll Benjamin
Published: March 2016

Background: Smoking cessation clinical trials assess tobacco abstinence using self-report and biomarkers. Optimum methods for each are unclear; a common question assesses smoking in the prior 7 days. In contrast, timeline follow-back (TLFB) is another technique often used to assess use of alcohol in treatment trials; it is used less frequently in studies of smoking cessation. The goal of this study was to assess concordance between the 7-day smoking question and a 7-day TLFB. Methods: Secondary analysis of data from a randomized clinical trial of smoking cessation was conducted at a busy, urban hospital emergency department (ED) from October 2010 to December 2012. At 1, 3, and 12 months, subjects were contacted by phone to assess smoking status. Those reporting abstinence at 3 months were asked to return for an in-person measurement of exhaled carbon monoxide. For this analysis, smoking status at 1 month was compared for subjects in response to 2 questions asked concurrently, addressing 7-day point prevalence tobacco use and a 7-day TLFB. Results: Of 780 subjects, 666 (85.4%) were available for 1-month follow-up. Of these, 99 (14.9%) reported no smoking in response to the 7-day question, and 96 (14.4%) reported no smoking in response to the 7-day TLFB. The overall proportionate agreement between the 2 methods was 98.6%, with a kappa of 0.95 (95% confidence interval [CI]: 0.91–0.98). Conclusions: A single question that assesses smoking at 7 days provides excellent concordance with the more detailed TLFB. The single question appears adequate to assess self-reported tobacco use in clinical trials of smoking cessation.
Gene expression pattern of glucose transporters in the skeletal muscles of newly hatched chicks
Authors: Shimamoto Saki , Ijiri Daichi , Kawaguchi Mana , Nakashima Kazuki , Ohtsuka Akira
Published: March 2016

The gene expression pattern of the glucose transporters (GLUT1, GLUT3, GLUT8, and GLUT12) among pectoralis major and minor, biceps femoris, and sartorius muscles from newly hatched chicks was examined. GLUT1 mRNA level was higher in pectoralis major muscle than in the other muscles. Phosphorylated AKT level was also high in the same muscle, suggesting a relationship between AKT and GLUT1 expression.
Eigenvalue bounds for Schrödinger operators with complex potentials. III
Authors: Frank Rupert
Published: March 2016

We discuss the eigenvalues

E
j

E_j

of Schrödinger operators

−
Δ
+
V

-\Delta +V

in

L
2

(

R

d

)

L^2(\mathbb {R}^d)

with complex potentials

V
∈

L
p

V\in L^p

,

p
>
∞

p>\infty

. We show that (A)

Re
⁡

E
j

→
∞

\operatorname {Re} E_j\to \infty

implies

Im
⁡

E
j

→
0

\operatorname {Im} E_j\to 0

, and (B)

Re
⁡

E
j

→
E
∈
[
0
,
∞
)

\operatorname {Re} E_j\to E\in [0,\infty )

implies

(
Im
⁡

E
j

)
∈

ℓ
q

(\operatorname {Im} E_j)\in \ell ^q

for some

q
q

depending on

p
p

. We prove quantitative versions of (A) and (B) in terms of the

L
p

L^p

-norm of

V
V

.
RBM4 promotes neuronal differentiation and neurite outgrowth by modulating Numb isoform expression
Authors: Tarn Woan-Yuh , Kuo Hung-Che , Yu Hsin-I. , Liu Shin-Wu , Tseng Ching-Tzu , Dhananjaya Dodda , Hung Kuan-Yang , Tu Chi-Chiang , Chang Shuo-Hsiu , Huang Guo-Jen , Chiu Ing-Ming
Published: March 2016

RBM4 participates in cell differentiation by regulating tissue-specific alternative pre-mRNA splicing. RBM4 also has been implicated in neurogenesis in the mouse embryonic brain. Using mouse embryonal carcinoma P19 cells as a neural differentiation model, we observed a temporal correlation between RBM4 expression and a change in splicing isoforms of Numb, a cell-fate determination gene. Knockdown of RBM4 affected the inclusion/exclusion of exons 3 and 9 of Numb in P19 cells. RBM4-deficient embryonic mouse brain also exhibited aberrant splicing of Numb pre-mRNA. Using a splicing reporter minigene assay, we demonstrated that RBM4 promoted exon 3 inclusion and exon 9 exclusion. Moreover, we found that RBM4 depletion reduced the expression of the proneural gene Mash1, and such reduction was reversed by an RBM4-induced Numb isoform containing exon 3 but lacking exon 9. Accordingly, induction of ectopic RBM4 expression in neuronal progenitor cells increased Mash1 expression and promoted cell differentiation. Finally, we found that RBM4 was also essential for neurite outgrowth from cortical neurons in vitro. Neurite outgrowth defects of RBM4-depleted neurons were rescued by RBM4-induced exon 9–lacking Numb isoforms. Therefore our findings indicate that RBM4 modulates exon selection of Numb to generate isoforms that promote neuronal cell differentiation and neurite outgrowth.
To Do Him Bodily Harm
Authors: Gross Kali Nicole
Published: March 2016

Chapter 3 takes a closer look at the woman at the center of the case. Tracing the history of Hannah Mary Tabbs, from her origins in Maryland through her marriage and migration to Philadelphia, the chapter also examines her prolific history of violence—within her family, community, and her extramarital affair with the victim. This chapter also explores the ways that Tabbs managed to appear to uphold traditional social mores, while operating with a vastly different set of values. It argues that this duality, fraught though it may be, allowed Tabbs to enjoy a high degree of social control and personal autonomy. At the same, it also points out how her violence, too, highlights black women’s vulnerability and the need for most black women to be able to protect themselves in lieu of equitable policing or protection.
The syntax of questions
Authors: Holmberg Anders
Published: March 2016

Charles Hamblin’s theory of the semantics of questions is adopted as the basis of the theory of the syntax of yes–no questions. Syntactically there are two types of questions: those which list the alternatives overtly and those in which the alternatives are encoded as a variable, the question variable. The question variable in yes–no questions is a feature [±Pol(arity)], which is assigned a value in the answer. Chinese A-not-A questions are discussed, as a representative of the syntax of yes–no questions, A-not-A being the expression of [±Pol]. Yes–no questions in Finnish, English, and Thai are discussed, in particular how the question variable [±Pol] is encoded. The notion focus and disjunction are discussed. The possibility of negative questions shows that negation and polarity are distinct categories.
Who Decides the Shape of Product Markets?
Authors: Pollock Neil , Williams Neil
Published: March 2016

Who decides the boundaries around a product terminology? The ‘technology classifications’ which frame and define boundaries around technology fields are an important part of the ‘knowledge infrastructure’ on which markets operate. Here, Gartner makes regular ‘naming interventions’ within the IT domain. Considering the evolution of Customer Relationship Management (CRM) software, the chapter shows how Gartner attempted to regulate the boundaries around this technology category and to exercise control over a terminology (‘classification work’) and its interpretation in particular instances (‘categorization work’). As well as building frames around new terminologies/naming interventions they may adopt and perhaps repurpose an existing terminology. However this framing work is bound up and entangled with the responses of wider communities of users. Gartner may need to manage divergences of view within Gartner; it may be called to defend frames in the face of external challenges and even abandon a framing.