bluuebunny/crossref_metadata_2025 huggingface dataset:
Research and practice on incorporating mobile sources into Shenzhen carbon emissions trading system
Authors: Cai Yu , Dudek Dan , Ma Xiaoming , Zhang Jianyu , Margolis Josh , Liu Bella , Ji Junping
Published: July 2015

This paper describes the progress of the research and practice on incorporating mobile sources, especially motor vehicles, into Shenzhen Emissions Trading System. Insights gained through Shenzhen's experience will provide useful insights to others that may have cause to consider the expansion of their Emissions Trading System (ETS) to include mobile sources. In order to incorporate public transportation into the ETS pilot, the city has formulated quantitative greenhouse gas emissions standards for bus and taxi companies, drawn the baselines for energy consumption and carbon emissions of public transportation, and revised local emissions trading regulations. For the further inclusion of non-public transportation vehicles, studies were made on emissions quantification, allowances allocation, non-compliance penalties, and emission reductions certification. In the future, the work will focus on legal safeguards and trading mechanisms.
Analytic drain current model for III–V cylindrical nanowire transistors
Authors: Marin E. G. , Ruiz F. G. , Schmidt V. , Godoy A. , Riel H. , Gámiz F.
Published: July 2015

An analytical model is proposed to determine the drain current of III–V cylindrical nanowires (NWs). The model uses the gradual channel approximation and takes into account the complete analytical solution of the Poisson and Schrödinger equations for the Γ-valley and for an arbitrary number of subbands. Fermi–Dirac statistics are considered to describe the 1D electron gas in the NWs, being the resulting recursive Fermi–Dirac integral of order −1/2 successfully integrated under reasonable assumptions. The model has been validated against numerical simulations showing excellent agreement for different semiconductor materials, diameters up to 40 nm, gate overdrive biases up to 0.7 V, and densities of interface states up to 1013eV−1cm−2.
Electromagnetic drift waves dispersion for arbitrarily collisional plasmas
Authors: Lee Wonjae , Angus J. R. , Krasheninnikov Sergei I.
Published: July 2015

The impacts of the electromagnetic effects on resistive and collisionless drift waves are studied. A local linear analysis on an electromagnetic drift-kinetic equation with Bhatnagar-Gross-Krook-like collision operator demonstrates that the model is valid for describing linear growth rates of drift wave instabilities in a wide range of plasma parameters showing convergence to reference models for limiting cases. The wave-particle interactions drive collisionless drift-Alfvén wave instability in low collisionality and high beta plasma regime. The Landau resonance effects not only excite collisionless drift wave modes but also suppress high frequency electron inertia modes observed from an electromagnetic fluid model in collisionless and low beta regime. Considering ion temperature effects, it is found that the impact of finite Larmor radius effects significantly reduces the growth rate of the drift-Alfvén wave instability with synergistic effects of high beta stabilization and Landau resonance.
Origin of melting point depression for rare gas solids confined in carbon pores
Authors: Morishige Kunimitsu , Kataoka Takaaki
Published: July 2015

To obtain insights into the mechanism of the melting-point depression of rare gas solids confined in crystalline carbon pores, we examined the freezing and melting behavior of Xe and Ar confined to the crystalline pores of ordered mesoporous carbons as well as compressed exfoliated graphite compared to the amorphous pores of ordered mesoporous silicas, by means of X-ray diffraction. For the Xe and Ar confined to the crystalline carbon pores, there was no appreciable thermal hysteresis between freezing and melting. Furthermore, the position of the main diffraction peak did not change appreciably on freezing and melting. This strongly suggests that the liquids confined in the carbon pores form a multilayered structure parallel to the smooth walls. For the Xe and Ar confined to the amorphous silica pores, on the other hand, the position of the main diffraction peak shifted into higher scattering angle on freezing suggested that the density of the confined solid is distinctly larger than for the confined liquid. Using compressed exfoliated graphite with carbon walls of higher crystallinity, we observed that three-dimensional (3D) microcrystals of Xe confined in the slit-shaped pores melted to leave the unmelted bilayers on the pore walls below the bulk triple point. The lattice spacing of the 3D microcrystals confined is larger by ∼0.7% than that of the bilayer next to the pore walls in the vicinity of the melting point.
Modeling interface exchange coupling: Effect on switching of granular FePt films
Authors: Abugri Joseph B. , Visscher P. B. , Su Hao , Gupta Subhadra
Published: July 2015

To raise the areal density of magnetic recording to ∼1 Tbit/in2, there has been much recent work on the use of FePt granular films, because their high perpendicular anisotropy allows small grains to be stable. However, their coercivity may be higher than available write-head fields. One approach to reduce the coercivity is to heat the grain (heat assisted magnetic recording). Another strategy is to add a soft capping layer to help nucleate switching via exchange coupling with the hard FePt grains. We have simulated a model of such a capped medium and have studied the effect of the strength of the interface exchange and thickness of hard layer and soft layer on the overall coercivity. Although the magnetization variation within such boundary layers may be complex, the net effect of the boundary can often be modeled as an infinitely thin interface characterized by an interface exchange energy density—we show how to do this consistently in a micromagnetic simulation. Although the switching behavior in the presence of exchange, magnetostatic, and external fields is quite complex, we show that by adding these fields one at a time, the main features of the M-H loop can be understood. In particular, we find that even without hard-soft interface exchange, magnetostatic coupling eliminates the zero-field kink in the loop, so that the absence of the kink does not (as has sometimes been assumed) imply exchange coupling. The computations have been done with a public-domain micromagnetics simulator that has been adapted to easily simulate arrays of grains.
Lubrication analysis of interacting rigid cylindrical particles in confined shear flow
Authors: Cardinaels R. , Stone H. A.
Published: July 2015

Lubrication analysis is used to determine analytical expressions for the elements of the resistance matrix describing the interaction of two rigid cylindrical particles in two-dimensional shear flow in a symmetrically confined channel geometry. The developed model is valid for non-Brownian particles in a low-Reynolds-number flow between two sliding plates with thin gaps between the two particles and also between the particles and the walls. Using this analytical model, a comprehensive overview of the dynamics of interacting cylindrical particles in shear flow is presented. With only hydrodynamic interactions, rigid particles undergo a reversible interaction with no cross-streamline migration, irrespective of the confinement value. However, the interaction time of the particle pair substantially increases with confinement, and at the same time, the minimum distance between the particle surfaces during the interaction substantially decreases with confinement. By combining our purely hydrodynamic model with a simple on/off non-hydrodynamic attractive particle interaction force, the effects of confinement on particle aggregation are qualitatively mapped out in an aggregation diagram. The latter shows that the range of initial relative particle positions for which aggregation occurs is increased substantially due to geometrical confinement. The interacting particle pair exhibits tangential and normal lubrication forces on the sliding plates, which will contribute to the rheology of confined suspensions in shear flow. Due to the combined effects of the confining walls and the particle interaction, the particle velocities and resulting forces both tangential and perpendicular to the walls exhibit a non-monotonic evolution as a function of the orientation angle of the particle pair. However, by incorporating appropriate scalings of the forces, velocities, and doublet orientation angle with the minimum free fraction of the gap height and the plate speed, master curves for the forces versus orientation angle can be constructed.
Complementary split ring resonator arrays for electromagnetic energy harvesting
Authors: Alavikia Babak , Almoneef Thamer S. , Ramahi Omar M.
Published: July 2015

This work demonstrates the viability of Ground-backed Complementary Split-Ring Resonator (G-CSRR) arrays with significant power conversion efficiency and bandwidth enhancement in comparison to the technology used in current electromagnetic energy harvesting systems. Through numerical full-wave analysis, we demonstrated correlation between either the resonance frequency or the input impedance of G-CSRR cells with the periodicity of the array. A comparative study of power harvesting efficiency through numerical analysis and laboratory measurement was presented where an array of G-CSRRs is compared to an array of microstrip patch antennas. We demonstrated that a G-CSRR array yields power conversion efficiency of 92%, which represents a significant improvement in comparison to the single G-CSRR reported in our earlier work.
New (1 − x)K0.45Na0.55Nb0.96Sb0.04O3-xBi0.5Na0.5HfO3 lead-free ceramics: Phase boundary and their electrical properties
Authors: Tao Hong , Wu Jiagang , Zheng Ting , Wang Xiangjian , Lou Xiaojie
Published: July 2015

Here, we reported a high unipolar strain and large piezoelectricity in new (1 − x)K0.45Na0.55Nb0.96Sb0.04O3-xBi0.5Na0.5HfO3 ceramics. The rhombohedral-tetragonal (R-T) phase boundary was constructed in the ceramics with 0.03 < x ≤ 0.05, which shows a large d33 value of ∼419 pC/N. More importantly, a high unipolar strain of ∼0.31% was observed due to the multiphase coexistence. In addition, the piezoelectricity of the ceramics could be effectively enhanced if their compositions are located at the phase boundaries region, where a very low electric field of ∼1.2 kV/mm can readily rotate the R/T domains. We also noticed that the deviation from phase boundary induced by applying an external electric field results in the deterioration of piezoelectricity after the “second-poling” method. We believe that as a potassium-sodium-niobate based material, the ceramics developed in this work may find practical applications in lead-free piezoelectric devices such as actuators and fuel injectors in the future owing to the significant enhancement in their piezoelectricity as well as strain.
Enhanced switching uniformity in AZO/ZnO1−x/ITO transparent resistive memory devices by bipolar double forming
Authors: Simanjuntak Firman Mangasa , Panda Debashis , Tsai Tsung-Ling , Lin Chun-An , Wei Kung-Hwa , Tseng Tseung-Yuen
Published: July 2015

The influence of single and double forming on the switching stability of AZO/ZnO1−x/ITO transparent resistive memory devices was investigated. Devices that underwent single forming exhibited severe switching instability, where as those that underwent double forming exhibited excellent switching uniformity. The quantity of conducting filaments can be limited by applying the two-step forming process. Consequently, the set/reset process can be controlled, enhancing switching stability. Satisfactory endurance with an acceptable ON/OFF ratio of 102 and satisfactory retention behavior of 104 s at room temperature confirmed the reliability of optimized devices. Furthermore, highly transparent devices (transparency of approximately 85% in visible range) have been fabricated.
Controlled response wavelength shifting in ultraviolet photodetectors based on double-layer films
Authors: Liu Rusheng , Jiang Dayong , Duan Qian , Sun Long , Guo Zexuan , Pei Jianan , Qin Jieming , Zhao Jianxun , Hou Jianhua , Gao Shang , Liang Qingcheng , Liu Wanqiang
Published: July 2015

By integrating ZnO and MgZnO films onto a quartz substrate (both films with the same growth time), the ultraviolet photodetectors (Au/ZnO/MgZnO/SiO2 and Au/MgZnO/ZnO/SiO2 structured photodetectors) have been fabricated. The responsivity peaks blue-shift from 380 to 370 nm (380 to 375 nm) by increasing the bias voltage in 1.0 h (1.5 h) photodetectors, which is denoted by the growth time of one layer of the films. More interestingly, the Au/MgZnO/ZnO/SiO2 photodetectors shift the same response wavelength range at smaller bias voltages than the Au/ZnO/MgZnO/SiO2 photodetectors. The results are well-rationalized in term of the role played by the double-layer structure.
Iron and manganese-related magnetic centers in hexagonal silicon carbide: A possible roadmap for spintronic devices
Authors: Machado W. V. M. , Justo J. F. , Assali L. V. C.
Published: July 2015

The electronic and magnetic properties of manganese- and iron-doped 4H-SiC were investigated by first-principles calculations, using an all electron methodology. The results on stability, spin configurations, formation and transition energies, local magnetic moments, and hyperfine parameters were compared to available theoretical and experimental data. The results indicated that transition metal impurities are energetically more favorable in lattice sites with carbon atoms as their first nearest neighbors, in both substitutional and interstitial configurations, which results from the larger electronegativity of carbon with respect to that of silicon. The analysis of the electronic properties of those impurity centers showed that they could stay in several stable charge states, depending on the Fermi energy level position within the host SiC bandgap. Additionally, by computing the p-d exchange coupling constant, which is related to a spin polarization in the SiC valence band top, we explored the possibility of achieving macroscopic magnetism in SiC. The results indicated that some centers, in both substitutional and interstitial configurations, present reasonably strong magnetic couplings to mediate macroscopic magnetism at high temperatures, which may generate spin polarized currents, leading to applications in spintronic devices.
Analysis of scattering mechanisms in zinc oxide films grown by the atomic layer deposition technique
Authors: Krajewski Tomasz A. , Dybko Krzysztof , Luka Grzegorz , Wachnicki Lukasz , Kopalko Krzysztof , Paszkowicz Wojciech , Godlewski Marek , Guziewicz Elzbieta
Published: July 2015

In this work, the analysis of the temperature-dependent electrical conductivity of highly crystalline zinc oxide (ZnO) thin films obtained by the Atomic Layer Deposition (ALD) method is performed. It is deduced that the most important scattering mechanisms are: scattering by ionized defects (at low temperatures) as well as by phonons (mainly optical ones) at higher temperatures. Nevertheless, the role of grain boundaries in the carrier mobility limitation ought to be included as well. These conclusions are based on theoretical analysis and temperature-dependent Hall mobility measurements. The presented results prove that existing models can explain the mobility behavior in the ALD-ZnO films, being helpful for understanding their transport properties, which are strongly related both to the crystalline quality of deposited ZnO material and defects in its lattice.
Evidence for an iron-hydrogen complex in p-type silicon
Authors: Leonard S. , Markevich V. P. , Peaker A. R. , Hamilton B. , Murphy J. D.
Published: July 2015

Interactions of hydrogen with iron have been studied in Fe contaminated p-type Czochralski silicon using capacitance-voltage profiling and deep level transient spectroscopy (DLTS). Hydrogen has been introduced into the samples from a silicon nitride layer grown by plasma enhanced chemical vapor deposition. After annealing of the Schottky diodes on Si:Fe + H samples under reverse bias in the temperature range of 90–120 °C, a trap has been observed in the DLTS spectra which we have assigned to a Fe-H complex. The trap is only observed when a high concentration of hydrogen is present in the near surface region. The trap concentration is higher in samples with a higher concentration of single interstitial Fe atoms. The defect has a deep donor level at Ev + 0.31 eV. Direct measurements of capture cross section of holes have shown that the capture cross section is not temperature dependent and its value is 5.2 × 10−17 cm2. It is found from an isochronal annealing study that the Fe-H complex is not very stable and can be eliminated completely by annealing for 30 min at 125 °C.
Technical and economic assessment of perovskite solar cells for large scale manufacturing
Authors: Asif Amir A. , Singh Rajendra , Alapatt Githin F.
Published: July 2015

In this paper, we have carried out detailed technical and economic assessment of perovskite solar cells for large scale manufacturing. For ultra-small area of the order of 0.1 cm2, efficiency of 20% or so are reported. However, for area of 25 cm2, the efficiency is about 10%. Based on the photovoltaic module manufacturing requirements of no constraint on the supply of raw materials, low variability of every key process and process-induced defects, low cost of manufacturing, prospects for further cost reduction in the future, green manufacturing, and long-term reliability, there are absolutely no prospects of manufacturing perovskite solar cells. No one has commercialized perovskite solar cells. Thus, contrary to hype in the literature, there is no truth that perovskite solar cells will replace silicon solar cells. We have also examined the role of perovskite solar cells for increasing the efficiency of silicon solar cells and found unsuitable both for two and four terminal device architectures.
De-polarization of a CdZnTe radiation detector by pulsed infrared light
Authors: Dědič V. , Franc J. , Rejhon M. , Grill R. , Zázvorka J. , Sellin P. J.
Published: July 2015

This work is focused on a detailed study of pulsed mode infrared light induced depolarization of CdZnTe detectors operating at high photon fluxes. This depolarizing effect is a result of the decrease of positive space charge that is caused by the trapping of photogenerated holes at a deep level. The reduction in positive space charge is due to the optical transition of electrons from a valence band to the deep level due to additional infrared illumination. In this paper, we present the results of pulse mode infrared depolarization, by which it is possible to keep the detector in the depolarized state during its operation. The demonstrated mechanism represents a promising way to increase the charge collection efficiency of CdZnTe X-ray detectors operating at high photon fluxes.
Heat transfer through metal-graphene interfaces
Authors: Wejrzanowski Tomasz , Grybczuk Mateusz , Wasiluk Mateusz , Kurzydlowski Krzysztof J.
Published: July 2015

The paper presents the results of Molecular Dynamics (MD) studies of the thermal properties of Cu and Ag composites with single- (SLG) and multi-layered (MLG) graphene. We show that the thermal boundary conductance (TBC) of the metal-graphene interface drops significantly for the systems containing more than one layer of graphene. It is also concluded that the TBC for a single graphene layer is significantly higher for silver than for copper. For both systems, however, we found that the interface is a barrier for heat transfer with the thermal conductance being at least two orders of magnitude lower than for metal. Moreover, we found that the TBC decreases with an increase in the number of graphene layers. The interfacial effect becomes negligible for a thickness bigger than two graphene layers. Above this thickness the thermal conductivity of the region of multilayered graphene is not influenced by the interface and becomes similar to that of graphite. The results are compared with available experimental data and discussed in terms of the rules for designing composites of a high thermal conductivity.
Refractive indices and birefringence of hybrid liquid crystal - nanoparticles composite materials in the terahertz region
Authors: Mavrona E. , Chodorow U. , Barnes M. E. , Parka J. , Palka N. , Saitzek S. , Blach J.-F. , Apostolopoulos V. , Kaczmarek M.
Published: July 2015

We show that a hybrid LC-ferroelectric nanoparticle suspension of liquid crystal E7 doped with BaTiO3 nanoparticles leads to 10% increase in birefringence in the THz region of spectrum as compared to pure E7. Doped liquid crystals can be used to increase performance of THz modulators and waveplates. BaTiO3 nanoparticles used in the mixture were synthesised with the sol gel technique, and their refractive index has been measured in THz in powder form and in solution.
Controlling the angular radiation of single emitters using dielectric patch nanoantennas
Authors: Yang Yuanqing , Li Qiang , Qiu Min
Published: July 2015

Dielectric nanoantennas have generated much interest in recent years owing to their low loss and optically induced electric and magnetic resonances. In this paper, we investigate the coupling between a single emitter and dielectric patch nanoantennas. For the coupled system involving non-spherical structures, analytical Mie theory is no longer applicable. A semi-analytical model is proposed instead to interpret the coupling mechanism and the radiation characteristics of the system. Based on the presented model, we demonstrate that the angular emission of the single emitter can be not only enhanced but also rotated using the dielectric patch nanoantennas.
Enhanced sheet carrier densities in polarization controlled AlInN/AlN/GaN/InGaN field-effect transistor on Si (111)
Authors: Hennig J. , Dadgar A. , Witte H. , Bläsing J. , Lesnik A. , Strittmatter A. , Krost A.
Published: July 2015

We report on GaN based field-effect transistor (FET) structures exhibiting sheet carrier densities of n = 2.9 1013 cm−2 for high-power transistor applications. By grading the indium-content of InGaN layers grown prior to a conventional GaN/AlN/AlInN FET structure control of the channel width at the GaN/AlN interface is obtained. The composition of the InGaN layer was graded from nominally xIn = 30 % to pure GaN just below the AlN/AlInN interface. Simulations reveal the impact of the additional InGaN layer on the potential well width which controls the sheet carrier density within the channel region of the devices. Benchmarking the InxGa1−xN/GaN/AlN/Al0.87In0.13N based FETs against GaN/AlN/AlInN FET reference structures we found increased maximum current densities of ISD = 1300 mA/mm (560 mA/mm). In addition, the InGaN layer helps to achieve broader transconductance profiles as well as reduced leakage currents.
Optical and electro-optic anisotropy of epitaxial PZT thin films
Authors: Zhu Minmin , Du Zehui , Jing Lin , Yoong Tok Alfred Iing , Tong Teo Edwin Hang
Published: July 2015

Strong optical and electro-optic (EO) anisotropy has been investigated in ferroelectric Pb(Zr0.48Ti0.52)O3 thin films epitaxially grown on Nb-SrTiO3 (001), (011), and (111) substrates using magnetron sputtering. The refractive index, electro-optic, and ferroelectric properties of the samples demonstrate the significant dependence on the growth orientation. The linear electro-optic coefficients of the (001), (011), and (111)-oriented PZT thin films were 270.8, 198.8, and 125.7 pm/V, respectively. Such remarkable anisotropic EO behaviors have been explained according to the structure correlation between the orientation dependent distribution, spontaneous polarization, epitaxial strain, and domain pattern.
Model for flow of Casson nanofluid past a non-linearly stretching sheet considering magnetic field effects
Authors: Mustafa M. , Khan Junaid Ahmad
Published: July 2015

Present work deals with the magneto-hydro-dynamic flow and heat transfer of Casson nanofluid over a non-linearly stretching sheet. Non-linear temperature distribution across the sheet is considered. More physically acceptable model of passively controlled wall nanoparticle volume fraction is accounted. The arising mathematical problem is governed by interesting parameters which include Casson fluid parameter, magnetic field parameter, power-law index, Brownian motion parameter, thermophoresis parameter, Prandtl number and Schmidt number. Numerical solutions are computed through fourth-fifth-order-Runge-Kutta integration approach combined with the shooting technique. Both temperature and nanoparticle volume fraction are increasing functions of Casson fluid parameter.
A novel wideband, low-profile and second-order miniaturized band-pass frequency selective surfaces
Authors: Xu Nianxi , Gao Jinsong , Zhao Jingli , Feng Xiaoguo
Published: July 2015

A novel wideband, low-profile and second-order miniaturized band-pass frequency selective surface (FSS) made of metallic mesh and its complementary structures with skewed arrays of modified triples is presented in this paper. Compared with traditional second-order bandpass FSSs obtained using λ/4 apart from one another, the novel FSS with an overall thickness of λ/18 is composed of three metallic layers (the outside and middle layers are complementary) separated by two electric thin dielectric substrates. This arrangement can shorten the inter-element spacing and increase the bandwidth, while the up and bottom metallic layers can constitute a symmetric biplanar FSS and thus realize ability of maximally flat second-order bandpass response. The novel FSS has a −3 dB bandwidth about 8.2 GHz (6.9 -15.1 GHz) and a fractional bandwidth exceeds 75%. Moreover, such an FSS has the merits of stable performance for incident angles within 50° and different polarizations. The principles of operation along with guidelines for the design of the proposed FSS, the simulated results by vector modal matching method, and the experimental values of the fabricated prototype are also presented and discussed.
Nearside-farside, local angular momentum and resummation theories: Useful tools for understanding the dynamics of complex-mode reactions
Authors: Hankel Marlies , Connor J. N. L.
Published: July 2015

A valuable tool for understanding the dynamics of direct reactions is Nearside-Farside (NF) scattering theory. It makes a decomposition of the (resummed) partial wave series for the scattering amplitude, both for the differential cross section (DCS) and the Local Angular Momentum (LAM). This paper makes the first combined application of these techniques to complex-mode reactions. We ask if NF theory is a useful tool for their identification, in particular, can it distinguish complex-mode from direct-mode reactions? We also ask whether NF theory can identify NF interference oscillations in the full DCSs of complex-mode reactions. Our investigation exploits the fact that accurate quantum scattering matrix elements have recently become available for complex-mode reactions. We first apply NF theory to two simple models for the scattering amplitude of a complex-mode reaction: One involves a single Legendre polynomial; the other involves a single Legendre function of the first kind, whose form is suggested by complex angular momentum theory. We then study, at fixed translational energies, four state-to-state complex-mode reactions. They are: S(1D) + HD → SH + D, S(1D) + DH → SD + H, N(2D) +H2 → NH + H, and H+ + D2 → HD + D+. We compare the NF results for the DCSs and LAMs with those for a state-to-state direct reaction, namely, F + H2 → FH + H. We demonstrate that NF theory is a valuable tool for identifying and analyzing the dynamics of complex-mode reactions.
Structural properties and optical characterization of flower-like Mg doped NiO
Authors: Allaedini Ghazaleh , Aminayi Payam , Tasirin Siti Masrinda
Published: July 2015

In this study, un-doped and Mg doped NiO nanoparticles have been synthesized through a simple sol-gel method. To investigate the effect of Mg-doping on the structure of NiO, the obtained nanoparticles were characterized using scanning electron microscopy (SEM). Flower/star like morphology was clearly observed in the SEM micrographs. The BET (Brunauer-Emmett-Teller) nitrogen absorption isotherm exhibits high specific surface area (∼37 m2 /g) for the Mg doped NiO nanoparticles. X-Ray diffraction (XRD) of the prepared Mg-NiO nanoparticles showed a face-centered cubic (f.c.c) structure, and the average particle size was estimated to be 32 nm using Scherrer’s formula. Energy Dispersive X-Ray (EDX) confirms that the NiO particles are successfully doped with Mg. Photoluminescence (PL) and UV-Vis optical absorption characteristics of the prepared nanoparticles have also been investigated in this study. The PL emission response showed a blue shift when NiO was doped with Mg, which is indicative of interstitial oxygen. The UV-Vis results demonstrate a band gap increase as NiO nanoparticles are doped with Mg.
Temperature variation in nest boxes in eastern Australia
Authors: Goldingay Ross L.
Published: July 2015

Nest boxes are frequently installed in Australia to provide shelter sites for arboreal mammals. Little is known about the temperatures that may be experienced inside nest boxes or the factors that may influence those temperatures. I established paired nest boxes on the south-east and north-west sides of trees at two locations in south-east Queensland to investigate the influence of nest box aspect on nest box temperature. Squirrel gliders (Petaurus norfolcensis) occupied boxes at both locations. I recorded temperatures over a 1-month period in two summers. Temperature varied by up to 20°C within a 24-h period and some nest boxes experienced temperatures above 40°C. There was no significant difference in maximum temperature with nest box aspect but south-east boxes could be 1°C cooler during hot weather. Nest box construction material, colour (brown or green) and volume (0.008 m3 or 0.025 m3) had variable influences on temperature. Nest box installations for non-flying mammals should place nest boxes to minimise extreme temperatures. Further studies are required to determine whether temperature limits the effectiveness of nest boxes at some locations.
Computational redesign of the lipid-facing surface of the outer membrane protein OmpA
Authors: Stapleton James A. , Whitehead Timothy A. , Nanda Vikas
Published: July 2015

Significance

The ability to construct novel proteins from basic principles of molecular structure is the fundamental goal of protein design. This is particularly challenging in the case of the β-barrel outer membrane proteins, where our understanding of the rules governing structure and function lags behind that of other classes of proteins. Here, we took a step toward understanding β-barrel membrane protein architecture by focusing on the outward-facing amino acid positions that contact the cell membrane. We replaced the membrane-facing surface of OmpA with new surfaces designed to resemble natural β-barrel surfaces. We were able to design versions of OmpA with mutations at about two-thirds of all surface positions, indicating that β-barrel membrane protein surface design is achievable.
Respiratory and Limb Muscle Dysfunction in Pulmonary Arterial Hypertension: A Role for Exercise Training?
Authors: Panagiotou Marios , Peacock Andrew J. , Johnson Martin K.
Published: July 2015

Respiratory and limb muscle dysfunction is emerging as an important pathophysiological abnormality in pulmonary arterial hypertension (PAH). Muscle abnormalities appear to occur frequently and promote dyspnea, fatigue, and exercise limitation in patients with PAH. Preliminary data suggest that targeted muscle training may be of benefit, although further evidence is required to consolidate these findings into specific recommendations for exercise training in patients with PAH. This article reviews the current evidence on prevalence, risk factors, and implications of respiratory and limb muscle dysfunction in patients with PAH. It also reviews the impact of exercise rehabilitation on morphologic, metabolic, and functional muscle profile and outcomes in PAH. Future research priorities are highlighted.
Investigations of initial particle stages during spark discharge
Authors: Ludvigsson Linus , Meuller Bengt O , Messing Maria E
Published: July 2015

The number of nanoparticle-based products on the market is expected to increase considerably during the coming decades. This forces the industry to have highly meticulous manufacturing of large amounts of nanoparticles using cheap and environmentally friendly methods. For the production of metal nanoparticles spark discharge generation is a promising route to fulfill these demands. The spark discharge generator can be easily scaled-up for mass production due to its simple design solely by placing several units in parallel. Before doing so, one first needs to optimize a single spark discharge generator unit. To optimize the spark discharge generator in a controlled way the first stage of nanoparticle formation needs to be understood. To improve this understanding we have constructed a customized nanoparticle sampler to enable sampling of the initial stages of particle formation for imaging in a TEM. In this article we present the design of the sampler and discuss optimal sampling parameters. We also present how the generation parameters can be tuned in order to affect the first stages of particle formation and hence the final nanoparticles.
Gender Differences in Rates of Carriage and Bloodstream Infection Caused by Methicillin-Resistant Staphylococcus aureus: Are They Real, Do They Matter and Why?
Authors: Humphreys Hilary , Fitzpatick Fidelma , Harvey Brian J.
Published: July 2015

There is increasing interest in sexual and gender dimorphism in disease. We reviewed the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) carriage and bloodstream infection (BSI), which shows a male predominance, and explored some of the possible reasons. Males are more prone to bacterial sepsis, but some studies suggest females may have a poorer prognosis from BSI. Hand-hygiene behavior varies according to gender. Males are less compliant, which in turn may predispose them to higher colonization and infection rates. Female hormones such as estrogen affect the expression of virulence factors in Pseudomonas aeruginosa, and although not studied, this may also apply to S. aureus. Further research is required on the relationship between gender and risk of infection, the reasons for higher MRSA carriage and BSI rates in males, the value of gender-specific infection prevention campaigns, and other factors such as the possible role of contact sports and occupation.
Ocean acidification affects productivity but not the severity of thermal bleaching in some tropical corals
Authors: Noonan Sam H. C. , Fabricius Katharina E.
Published: July 2015

Increasing carbon dioxide (CO2) emissions are raising sea surface temperature (SST) and causing ocean acidification (OA). While higher SST increases the frequency of mass coral bleaching events, it is unclear how OA will interact to affect this process. In this study, we combine in situ bleaching surveys around three tropical CO2 seeps with a 2-month two-factor (CO2 and temperature) tank experiment to investigate how OA and SST in combination will affect the bleaching susceptibility of tropical reef corals. Surveys at CO2 seep and control sites during a minor regional bleaching event gave little indication that elevated pCO2 influenced the bleaching susceptibility of the wider coral community, the four most common coral families (Acroporidae, Faviidae, Pocilloporidae, or Poritidae), or the thermally sensitive coral species Seriatopora hystrix. In the tank experiment, sublethal bleaching was observed at 31°C after 5 d in S. hystrix and 12 d in Acropora millepora, whereas controls (28°C) did not bleach. None of the measured proxies for coral bleaching was negatively affected by elevated pCO2 at pHT 7.79 (vs. 7.95 pHT in controls), equivalent to ∼780 µatm pCO2 and an aragonite saturation state of 2.5. On the contrary, high pCO2 benefitted some photophysiological measures (although temperature effects were much stronger than CO2 effects): maximum photosystem II quantum yields and light-limited electron transport rates increased in both species at high pCO2, whereas gross photosynthesis and pigment concentrations increased in S. hystrix at high pCO2. The field and laboratory data in combination suggest that OA levels up to a pHT of 7.8 will have little effect on the sensitivity of tropical corals to thermal bleaching. Indeed, some species appear to be able to utilize the more abundant dissolved inorganic carbon to increase productivity; however, these gains offset only a small proportion of the massive bleaching-related energy losses during thermal stress.
Toll pathway modulates TNF-induced JNK-dependent cell death inDrosophila
Authors: Wu Chenxi , Chen Changyan , Dai Jianli , Zhang Fan , Chen Yujun , Li Wenzhe , Pastor-Pareja José Carlos , Xue Lei
Published: July 2015

Signalling networks that control the life or death of a cell are of central interest in modern biology. While the defined roles of the c-Jun N-terminal kinase (JNK) pathway in regulating cell death have been well-established, additional factors that modulate JNK-mediated cell death have yet to be fully elucidated. To identify novel regulators of JNK-dependent cell death, we performed a dominant-modifier screen inDrosophilaand found that the Toll pathway participates in JNK-mediated cell death. Loss of Toll signalling suppresses ectopically and physiologically activated JNK signalling-induced cell death. Our epistasis analysis suggests that the Toll pathway acts as a downstream modulator for JNK-dependent cell death. In addition, gain of JNK signalling results in Toll pathway activation, revealed by stimulated transcription ofDrosomycin(Drs) and increased cytoplasm-to-nucleus translocation of Dorsal. Furthermore, the Spätzle (Spz) family ligands for the Toll receptor are transcriptionally upregulated by activated JNK signalling in a non-cell-autonomous manner, providing a molecular mechanism for JNK-induced Toll pathway activation. Finally, gain of Toll signalling exacerbates JNK-mediated cell death and promotes cell death independent of caspases. Thus, we have identified another important function for the evolutionarily conserved Toll pathway, in addition to its well-studied roles in embryonic dorso-ventral patterning and innate immunity.
On the approximation of isochoric motions of fluids under different flow conditions
Authors: Rajagopal K. R. , Saccomandi G. , Vergori L.
Published: July 2015

There has been considerable interest, ever since the development of the approximation by Oberbeck and Boussinesq concerning fluids that are mechanically incompressible but thermally compressible, in giving a rigorous justification for the same. For such fluids, it would be natural to assume that the determinant of the deformation gradient (which is a measure of the volume change of the body) depends on the temperature. However, such an assumption has the attendant drawbacks of the specific heat of the fluid at constant volume being zero and the speed of sound in the fluid being complex. In this paper, we consider a generalization of the Oberbeck–Boussinesq approximation, wherein the volume change depends both on the temperature and on the pressure that the fluid is subject to. We show that within the context of this generalization, the specific heat at constant volume can be defined meaningfully, and it is not zero.
New insights into carbon acquisition and exchanges within the coral–dinoflagellate symbiosis under NH
4
+
and NO
3
−
supply
Authors: Ezzat Leïla , Maguer Jean-François , Grover Renaud , Ferrier-Pagès Christine
Published: July 2015

Anthropogenic nutrient enrichment affects the biogeochemical cycles and nutrient stoichiometry of coastal ecosystems and is often associated with coral reef decline. However, the mechanisms by which dissolved inorganic nutrients, and especially nitrogen forms (ammonium versus nitrate) can disturb the association between corals and their symbiotic algae are subject to controversial debate. Here, we investigated the coral response to varying N : P ratios, with nitrate or ammonium as a nitrogen source. We showed significant differences in the carbon acquisition by the symbionts and its allocation within the symbiosis according to nutrient abundance, type and stoichiometry. In particular, under low phosphate concentration (0.05 µM), a 3 µM nitrate enrichment induced a significant decrease in carbon fixation rate and low values of carbon translocation, compared with control conditions (N : P = 0.5 : 0.05), while these processes were significantly enhanced when nitrate was replaced by ammonium. A combined enrichment in ammonium and phosphorus (N : P = 3 : 1) induced a shift in nutrient allocation to the symbionts, at the detriment of the host. Altogether, these results shed light into the effect of nutrient enrichment on reef corals. More broadly, they improve our understanding of the consequences of nutrient loading on reef ecosystems, which is urgently required to refine risk management strategies.
Bayesian analysis of a morphological supermatrix sheds light on controversial fossil hominin relationships
Authors: Dembo Mana , Matzke Nicholas J. , Mooers Arne Ø. , Collard Mark
Published: July 2015

The phylogenetic relationships of several hominin species remain controversial. Two methodological issues contribute to the uncertainty—use of partial, inconsistent datasets and reliance on phylogenetic methods that are ill-suited to testing competing hypotheses. Here, we report a study designed to overcome these issues. We first compiled a supermatrix of craniodental characters for all widely accepted hominin species. We then took advantage of recently developed Bayesian methods for building trees of serially sampled tips to test among hypotheses that have been put forward in three of the most important current debates in hominin phylogenetics—the relationship betweenAustralopithecus sedibaandHomo, the taxonomic status of the Dmanisi hominins, and the place of the so-called hobbit fossils from Flores, Indonesia, in the hominin tree. Based on our results, several published hypotheses can be statistically rejected. For example, the data do not support the claim that Dmanisi hominins and all other earlyHomospecimens represent a single species, nor that the hobbit fossils are the remains of small-bodied modern humans, one of whom had Down syndrome. More broadly, our study provides a new baseline dataset for future work on hominin phylogeny and illustrates the promise of Bayesian approaches for understanding hominin phylogenetic relationships.
EstimatingKin Genetic Mixture Models
Authors: Verity Robert , Nichols Richard A.
Published: July 2015

A key quantity in the analysis of structured populations is the parameterK, which describes the number of subpopulations that make up the total population. Inference ofKideally proceeds via themodel evidence, which is equivalent to the likelihood of the model. However, the evidence in favour of a particular value ofKcannot usually be computed exactly, and instead programs such as Structuremake use of simple heuristic estimators to approximate this quantity. We show – using simulated data sets small enough that the true evidence can be computed exactly – that these simple heuristics often fail to estimate the true evidence, and that this can lead to incorrect conclusions aboutK.Our proposed solution is to use thermodynamic integration (TI) to estimate the model evidence. After outlining the TI methodology we demonstrate the effectiveness of this approach using a range of simulated data sets. We find that TI can be used to obtain estimates of the model evidence that are orders of magnitude more accurate and precise than those based on simple heuristics. Furthermore, estimates ofKbased on these values are found to be more reliable than those based on a suite of model comparison statistics. Our solution is implemented for models both with and without admixture in the software TrueK.
Anomalous X-ray diffraction study of Pr-substituted BaCeO3 − δ
Authors: Basbus Juan F. , Caneiro Alberto , Suescun Leopoldo , Lamas Diego G. , Mogni Liliana V.
Published: July 2015

The effect of Pr doping on the crystal structure and site occupancy was studied for the nominally synthesized BaCe1 − xPrxO3 − δ(x= 0, 0.2, 0.4, 0.6 and 0.8) perovskites using anomalous X-ray powder diffraction (AXRD) data and Rietveld analysis. Crystal structure parameters were accurately determined using 10 000 eV photons, and the Pr occupancy was refined using data collected with 5962 eV photons, close to the Pr LIIIabsorption edge. BaCe1 − xPrxO3 − δcrystallizes in thePnma(No. 62) space group for allxvalues. Pr cations are mainly located at the Ce sites (perovskitesBsite), but a small fraction of them increasingly substitute some of the Ba ions at theAsite as Pr content increases. The Pr doping introduces electronic defects (Pr+3/Pr+4) and oxygen vacancies needed for H2O incorporation and H-ionic conductivity. A decrease in the orthorhombic distortion would produce the opposite effects on the electronic and ionic mobility. The electronic mobility should increase due to an improvement in the overlap of the (Ce/Pr)4f–O2porbital, while the proton mobility should decrease as a consequence of a larger hopping distance.
Crystal structure and phase transition in (NH4)3WO2F5: from dynamic to static orientational disorder
Authors: Udovenko Anatoly , Laptash Natalia
Published: July 2015

Single crystals of tungsten double salt (NH4)3WO2F5= (NH4)3[WO2F4]F have been synthesized by solid-state reaction or from fluoride solution and its crystal structures at 296 and 193 K were determined by X-ray diffraction. At room temperature, the crystal structure of the compound is dynamically disordered with the ligand atoms statistically distributed on two positions (6eand 24m) of thePm3munit cell [a= 6.0298 (1) Å], and the tungsten atom dynamically disordered on 12 orientations forming a spatial cuboctahedron [W12] that enables the real geometry ofcis-WO2F4octahedron to be determined with two short W—O distances. On cooling, the compound undergoes a first-order phase transition with the symmetry changePm3m→Pa3 and a doubling of the unit-cell parameter [a= 11.9635 (7) Å]. The ligand F(O) atoms statistically occupy two general 24dsites and form W1X6and W2X6octahedra, in which the O and F atoms are not crystallographically different that means a static orientational disorder of (NH4)3WO2F5.
The generation of adaptive assembly from predicting change propagation
Authors: Qiao Hu , Mo Rong , Xiang Ying
Published: July 2015

Purpose

– The purpose of this paper is to establish an adaptive assembly, to realize the adaptive changing of the models and to improve the flexibility and reliability of assembly change. For a three-dimensional (3D) computer-aided design (CAD) assembly in a changing process, there are two practical problems. One is delivering parameters’ information not smoothly. The other one is to easily destroy an assembly structure.

Design/methodology/approach

– The paper establishes associated parameters design structure matrix of related parts, and predicts possible propagation paths of the parameters. Based on the predicted path, structured storage is made for the affected parameters, tolerance range and the calculation relations. The study combines structured path information and all constrained assemblies to build the adaptive assembly, proposes an adaptive change algorithm for assembly changing and discusses the extendibility of the adaptive assembly.

Findings

– The approach would improve the flexibility and reliability of assembly change and be applied to different CAD platform.

Practical implications

– The examples illustrate the construction and adaptive behavior of the assembly and verify the feasibility and reasonability of the adaptive assembly in practical application.

Originality/value

– The adaptive assembly model proposed in the paper is an original method to assembly change. And compared with other methods, good results have been obtained.