bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations of GRO J1744–28 in quiescence with XMM-Newton
Authors: Doroshenko V. , Suleimanov V. , Tsygankov S. , Mönkkönen J. , Ji L. , Santangelo A.
Published: September 2020

We report on the deep observations of the “bursting pulsar” GRO J1744–28, which were performed with XMM-Newton and aimed to clarify the origin of its X-ray emission in quiescence. We detect the source at a luminosity level of ∼1034 erg s−1 with an X-ray spectrum that is consistent with the power law, blackbody, or accretion-heated neutron star atmosphere models. The improved X-ray localization of the source allowed us to confirm the previously identified candidate optical counterpart as a relatively massive G/K III star at 8 kpc close to the Galactic center, implying an almost face-on view of the binary system. Although we could only find a nonrestricting upper limit on the pulsed fraction of ∼20%, the observed hard X-ray spectrum and strong long-term variability of the X-ray flux suggest that the source is also still accreting when not in outburst. The luminosity corresponding to the onset of centrifugal inhibition of accretion is thus estimated to be at least two orders of magnitude lower than previously reported. We discuss this finding in the context of previous studies and argue that the results indicate a multipole structure in the magnetic field with the first dipole term of ∼1010 G, which is much lower than previously assumed.
Molecular remnant of Nova 1670 (CK Vulpeculae)
Authors: Kamiński Tomek , Menten Karl M. , Tylenda Romuald , Wong Ka Tat , Belloche Arnaud , Mehner Andrea , Schmidt Mirek R. , Patel Nimesh A.
Published: September 2020

CK Vul erupted in 1670 and is considered a Galactic stellar-merger candidate. Its remnant, observed 350 yr after the eruption, contains a molecular component of surprisingly rich composition, including polyatomic molecules as complex as methylamine (CH3NH2). We present interferometric line surveys with subarcsec resolution with ALMA and SMA. The observations provide interferometric maps of molecular line emission at frequencies between 88 and 243 GHz that allow imaging spectroscopy of more than 180 transitions of 26 species. We present, classify, and analyze the different morphologies of the emission regions displayed by the molecules. We also perform a non-LTE radiative-transfer analysis of emission of most of the observed species, deriving the kinetic temperatures and column densities in five parts of the molecular nebula. Non-LTE effects are clearly seen in complex species including methanol absorption against the cosmic microwave background. The temperatures are about 17 K in the inner remnant and 14 K in the extended lobes, both higher than excitation temperatures estimated earlier in an LTE approach and based on single-dish spectra. We find total (hydrogen plus helium) densities in the range of 104 − 106 cm−3. The column densities provide rough relative abundance patterns in the remnant which currently are not understood. Attempts to derive elemental abundances within the assumption of a chemical equilibrium give only loose constraints on the CNO elements. That the formation of many of the observed molecules requires a major involvement of circumstellar shocks remains the preferred possibility. The molecular gas could have formed 350 yr ago or more recently. The molecules are well shielded from the interstellar radiation field by the circumstellar dust. Their presence alone indicates that the unobservable central star cannot be a hot object such as a white dwarf. This excludes some of the proposed scenarios on the nature of CK Vul. The general characteristics of the molecular environment of CK Vul derived in this study resemble quite well those of some pre-planetary nebulae and asymptotic giant branch stars, most notably that of OH231.8+4.2.
Transfer Matrix Method for Dynamic Characteristics Analysis of Missile-Canister System in Silo
Authors: Zhou Anfeng , Li Daokui , Zhou Shiming , Cui Da , Zhou Xuan
Published: September 2020

In order to ensure the safety of the missile-canister system in silo during the earthquake, a modified transfer matrix method is provided to study the dynamic characteristics of the system. Firstly, a discrete viscoelastic connected double-beam model is developed taking account of the structural nonuniformity and the discrete distribution of the adapters. Secondly, the transfer matrix method of a single beam is modified to solve the problem of discrete connection between the two beams of the double-beam model. Then the natural circular frequencies and mode shapes are calculated by the proposed method, comparing with the finite element method (FEM). Finally, the influence of the stiffness of radial vibration isolators and adapters on the dynamic characteristics of the system is analysed. The comparison shows that the results of the proposed method are well consistent with the FEM calculations and the proposed method is validated. The variations of the first six natural circular frequencies with radial vibration isolator stiffness and adapter stiffness are obtained, which provides a basis for the seismic-relieving design.
Research on Prediction Model of Conical Pick Cutting Force Based on Coulomb-Mohr Criterion
Authors: Wang S.J. , Zong X.M. , He B. , Kang K.X.
Published: September 2020

Cutting force is one of the most important influence factors that affect the efficiency and service life of the conical pick. In order to accurately calculate the cutting force, through theoretical analysis and experimental research, a cutting force model consisted of the basic fracture parameters of rock, geometric parameters and installation parameters of pick is proposed based on the coulomb-mohr criterion, and the calculation model is corrected by whole cutting experimental data, and validated the corrected model by orthogonal test, the result show that the error of the cutting force model is about 10%, which meets the requirements of engineering data. At the same time, significant analysis on the cutting force is obtained by range method, cutting depth h > semi-tip angle β > cutting angle α.
Experimental analysis of gradient of negative temperature for polypropylene fiber concrete U-shaped girder
Authors: Dong Xu , Cui Fengkun , Li Xiudong , Xu Songji
Published: September 2020

To study the negative temperature gradient models of a rail transit U-shaped girder during the winter season, a U-shaped rail transit girder was researched in Qingdao. The temperature field of the midspan section was observed for a 48-h period during the winter. The maximum vertical and horizontal temperature difference distributions were obtained, and the negative temperature gradient models for the winter were established. The results show that the vertical temperature gradient models of the web and bottom slab should be considered. The vertical temperature gradient model of the web is a piecewise function composed of exponential and linear functions. The vertical temperature gradient model of the bottom slab is an exponential function. The transverse temperature gradient of the web is obvious, whereas the transverse temperature gradient of the bottom slab is slight.
Study on the potential change of corroded reinforced concrete in ECE with MPC-CFRP as anode
Authors: Li Yue , Zhang Xiuhu , Hejazi S.M.Ali S.
Published: September 2020

Aiming at the rust removal requirements of reinforced concrete, the MPC-CFRP composite material was used as the external anode, and the Electrochemical chloride extraction (ECE) method was used to test the polarization curve of the steel bar under different ECE current densities, and the potential changes of the steel bar at different times were analyzed. The results show that the ECE system with MPC-CFRP as the external anode has a good effect of reducing the corrosion rate and the risk of corrosion of steel bars. The current density of 3A/m2is higher than that of 1A/m2in dechlorination efficiency. After 28 days of ECE, the current density of 1A/m2and 3A/m2can re passivate the reinforcement.
Competition and cooperation models for dynamic pricing of perishable products in a two-echelon supply chain
Authors: Lou Zhenkai , Lou Xuming , Hou Fujun
Published: September 2020

This paper considers a two-level supply chain involving a supplier and a retailer. The retailer sells perishable products to consumers over a finite time horizon, and the demand is driven by a price-and-utility function. First, we study the noncooperative problem, which is formulated by a Stackelberg model. It is shown that the optimal pricing strategy of the retailer is to reduce a constant amount on the price at the beginning of each stage. Second, we examine the cooperative problem, in which the supplier and the retailer jointly price the product. Maximum selling cycle lengths of the two situations are obtained by analyzing the reasonability of the sales price. We demonstrate that the selling cycle length is extended by cooperation. Moreover, we show that they lower the sales price in the cooperative case so as to maximize the total profit. Meanwhile, an allocation method is provided based on the proportion.
Ernährung bei Pankreaserkrankungen
Authors: Kling Christiane
Published: September 2020

Bei Pankreaserkrankungen stellt die bedarfsgerechte Ernährung eine der wichtigsten Therapiesäulen dar. Der vorliegende Artikel zeigt nicht nur die leitlinienkonformen Ernährungsempfehlungen in den unterschiedlichen Therapiestadien auf, vielmehr soll er auch zur besseren interdisziplinären Zusammenarbeit innerhalb des Betreuungsteams anregen.
Neurosurgery in Contemporary Medical Dramas: How Grey's Anatomy & Co. May Affect Perception of Neurosurgery in the Media
Authors: Pilz Merle , Stummer Walter , Holling Markus
Published: September 2020

Background Neurosurgery is a common topic in contemporary medical dramas. This study aimed to examine depictions of several neurosurgical diseases and techniques as well as the perception of the personality of neurosurgeons in the media, focusing on their impact on the physician-patient relationship.

Methods TV series and movies with a main focus on neurosurgeons and/or neurosurgical diseases were identified by consulting the International Movie Database (IMDb).

Results After investigation of many TV series and movies, we identified five main topics: vascular neurosurgery, neuro-oncology, neurointensive care, neurosurgical techniques, and neurosurgeon's personality. The portrayal of neurosurgery in medical drama is characterized to a large extent by sensationalism, a lot of misinformation, and an unfavorable portrayal of neurosurgeons, although it is assumed that expert advice was sought in advance of every production.

Conclusions Considering the popularity of medical dramas and movies dealing with medical topics, we must consider the general public's picture of neurosurgery to be widely influenced by the media.
An Unusual Cause of Chylothorax after Esophagectomy
Authors: Manipadam John Mathew , Kumar Chokkappu S. , Antony Rajesh , Yadav Abhishek , Ramesh H.
Published: September 2020

Chylothorax due to inadvertent thoracic duct injury after esophagectomy is a well-known complication and requires careful postoperative management and timely intervention to prevent potential morbidity and mortality. We present a case of high-output chylothorax after esophagectomy where the source of chyle leak was not in the thorax.
Morphometric Study of the Posterior Fossa: Identification of Practical Parameters for Tailored Selection of Surgical Routes to the Petroclival Region
Authors: Aljuboori Zaid , Alhourani Ahmad , Nuru Mohammed , Nguyen Candice , Yeo Heegook , Williams Brian , Andaluz Norberto
Published: September 2020

Introduction The petroclival region is an integral part of the skull base. It can harbor different pathologies and provides access to the petroclival junction and cerebellopontine angle. We present the results of the morphometric analysis of the posterior fossa and a prediction model to enable skull base surgeons to choose an optimal surgical corridor considering patient's bony anatomy.

Methods Ninety patients (14 to assess interobserver reliability) with temporal bone computed tomography were selected. Exclusion criteria included patients <18 years of age, radiographic evidence of trauma, infection, or previous surgery. The images were analyzed using OsiriX MD (Bernex, Switzerland). We recorded clival length, vertical angle, and surface area, and petroclival angle, petrous apex, and translabyrinthine corridors volume.

Results The average age was 49.5 years (55%) for males. The mean clival length and surface areas were 44.2 mm (standard deviation [SD] ± 4.1) and 8.1 cm2 (SD ± 1.3). The mean petrous apex and translabyrinthine corridors volumes were 2.2 cm3 (SD ± 0.6) and 10.1 cm3 (SD ± 3.7). The mean petroclival angle at the internal auditory canal (IAC) was 154.9 degrees (SD ± 9). The clival length correlated positively with clival surface area (rho = 0.6, p <0.05), petrous apex volume (rho = 0.3, p < 0.05), and translabyrinthine volume (rho = 0.3, p < 0.05).

Conclusion The petroclival region is complex and with high variability of surgical significance. The use of preoperative measurements of the clival length and petroclival angle as part of surgical planning that could help the surgeon to choose an optimal surgical corridor by overcoming the anatomical variability elements.
Some mathematics for quasi-symmetry
Authors: Burby J. W. , Kallinikos N. , MacKay R. S.
Published: September 2020

Quasi-symmetry of a steady magnetic field means integrability of first-order guiding-center motion by a spatial symmetry. Here, we derive many restrictions on the possibilities for a quasi-symmetry. We also derive an analog of the Grad–Shafranov equation for the flux function in a quasi-symmetric magnetohydrostatic field.
Axial magnetic flux amplification in Hall-magnetohydrodynamic simulations of externally magnetized z-pinches
Authors: Seyler C. E.
Published: September 2020

It is shown that externally magnetized gas-puff z-pinches under compression can exhibit robust axial flux amplification under suitable axial boundary conditions. This effect relies upon the Hall term in the generalized Ohm's law to generate azimuthal currents in the presence of a driving axial electric field. Under dynamic compression, the total current tends to flow in a mostly force-free boundary layer, separating the predominately azimuthal field outside the layer and the predominately axial field inside the layer. The effect only appears to occur if the axial boundaries allow for outflow or absorption of electromagnetic energy. The effect is mitigated by imposing either periodic or conducting axial boundary conditions. A semi-analytic equilibrium analysis agrees with steady-state solutions of the time-dependent electron-magnetohydrodynamic equations and provides an estimate of the scaling of the boundary layer as well as suggesting a scenario for the formation of the boundary layer. When operative, the effect can significantly impede plasma compression due to the increase in axial flux that diffuses into the pre-compressed plasma or through the presence of conductors that inhibit movement of the generated axial flux. Several facilities have noted unusual implosion behavior in z-pinch experiments with applied axial fields that does not appear to be explainable within the standard magnetohydrodynamic model. It is suggested that these experiments can be explained by the axial flux amplification and concentration effect.
Generating a tide-like flow in a cylindrical vessel by electromagnetic forcing
Authors: Jüstel Peter , Röhrborn Sebastian , Frick Peter , Galindo Vladimir , Gundrum Thomas , Schindler Felix , Stefani Frank , Stepanov Rodion , Vogt Tobias
Published: September 2020

We show and compare the numerical and experimental results on the electromagnetic generation of a tide-like flow structure in a cylindrical vessel, which is filled with the eutectic liquid metal alloy GaInSn. Fields of various strengths and frequencies are applied to drive liquid metal flows. The impact of the field variations on amplitude and structure of the flow is investigated. The results represent the basis for a future Rayleigh–Bénard experiment, in which a modulated tide-like flow perturbation is expected to synchronize the typical sloshing mode of the large-scale circulation and the helicity oscillation connected with it. A similar entrainment mechanism might play a role in the synchronization of stellar dynamos by tidal forces.
Polymer escape through a three dimensional double-nanopore system
Authors: Seth Swarnadeep , Bhattacharya Aniket
Published: September 2020

We study the escape dynamics of a double-stranded DNA (dsDNA) through an idealized double nanopore geometry subject to two equal and opposite forces (tug-of-war) using Brownian dynamics (BD) simulation. In addition to the geometrical restrictions imposed on the cocaptured dsDNA segment in between the pores, the presence of tug-of-war forces at each pore results in a variation of the local chain stiffness for the segment of the chain in between the pores, which increases the overall stiffness of the chain. We use the BD simulation results to understand how the intrinsic chain stiffness and the tug-of-war forces affect the escape dynamics by monitoring the local chain persistence length ℓp, the residence time of the individual monomers W(m) in the nanopores, and the chain length dependence of the escape time ⟨τ⟩ and its distribution. Finally, we generalize the scaling theory for the unbiased single nanopore translocation for a fully flexible chain for the escape of a semi-flexible chain through a double nanopore in the presence of tug-of-war forces. We establish that the stiffness dependent part of the escape time is approximately independent of the translocation mechanism so that ⟨τ⟩∼ℓp2/D+2, and therefore, the generalized escape time for a semi-flexible chain can be written as ⟨τ⟩=ANαℓp2/D+2. We use the BD simulation results to compare the predictions of the scaling theory. Our numerical studies supplemented by scaling analysis provide fundamental insights to design new experiments where a dsDNA moves slowly through a series of graphene nanopores.
Radiation of twisted whistler waves from a crossed-loop antenna in a magnetoplasma
Authors: Kudrin Alexander V. , Zaboronkova Tatyana M. , Zaitseva Anna S. , Bazhilova Eva V.
Published: September 2020

A study is made of the radiation of whistler waves with helical phase fronts from nonsymmetric sources immersed in a homogeneous cold magnetoplasma. The emphasis is placed on calculating the radiation resistance of an antenna in the form of two orthogonally crossed circular loops with quadrature-phased currents using an approach that is based on an eigenfunction expansion representation of the excited field. Analytical and numerical results are reported for the radiation characteristics of such an antenna in the whistler range and differences in the behavior of the radiation resistance below and above the lower hybrid resonance frequency are revealed. The results obtained can be useful in understanding the basic features of excitation of twisted whistler waves in a magnetoplasma.
Equation of state of hot, dense magnesium derived with first-principles computer simulations
Authors: González-Cataldo Felipe , Soubiran François , Militzer Burkhard
Published: September 2020

Using two first-principles computer simulation techniques, path integral Monte Carlo and density functional theory molecular dynamics, we derive the equation of state of magnesium in the regime of warm dense matter, with densities ranging from 0.43 to 86.11 g cm−3 and temperatures from 20 000 K to 5×108 K. These conditions are relevant for the interiors of giant planets and stars as well as for shock compression measurements and inertial confinement fusion experiments. We study ionization mechanisms and the electronic structure of magnesium as a function of density and temperature. We show that the L shell electrons, 2s and 2p energy bands, merge at high densities. This results in gradual ionization of the L-shell with increasing density and temperature. In this regard, Mg differs from MgO, which is also reflected in the shape of its principal shock Hugoniot curve. For Mg, we predict a single broad pressure-temperature region, where the shock compression ratio is approximately 4.9. Mg thus differs from Si and Al plasmas that exhibit two well-separated compression maxima on the Hugoniot curve for L and K shell ionizations. Finally, we study multiple shocks and effects of preheat and precompression.
Ideal memristor based on viscous magnetization dynamics driven by spin torque
Authors: Chen Guanxiong , Ivanov Sergei , Urazhdin Sergei
Published: September 2020

We show that ideal memristors—devices whose resistance is proportional to the charge that flows through them—can be realized using spin torque-driven viscous magnetization dynamics. The latter can be accomplished in the spin liquid state of thin-film heterostructures with frustrated exchange, where the memristive response is tunable by proximity to the glass transition, while current-induced Joule heating facilitates non-volatile operation and second-order memristive functionality beneficial for neuromorphic applications. Ideal memristive behaviors can be achieved in other systems characterized by viscous dynamics of physical, electronic, or magnetic degrees of freedom.
Rotating missile self-infrared radiation interference compensation for dual-band infrared attitude measurement
Authors: Xu Miaomiao , Bu Xiongzhu , Chen Xiaomin , Song Yang
Published: September 2020

In order to solve the problem of large rotating missile surface infrared radiation interference during the dual-band infrared radiation attitude measurement and improve the infrared attitude measurement accuracy, the rotating missile self-infrared radiation compensation method is studied. Based on the six degree of freedom ballistic model, the surface temperature and infrared radiation characteristics of the missile are studied, and the surface temperature equation of the rotating missile is derived. According to the propagation law of dual-band infrared radiation in the atmosphere, the brightness of missile body dual-band infrared radiation is calculated, the mathematical model of dual-band infrared radiation compensation of the missile body is established, and the attitude compensation parameters of dual-band infrared radiation are simulated. The results of semi-physical experiments show that the error of attitude angle calculation after missile self-infrared radiation interference compensation is significantly reduced, and the attitude angle calculation accuracy is increased by more than 2.5 times. The compensation method provides an effective technical implementation method for the rotating missile self-infrared radiation interference compensation.
Controlled giant magnetoresistance and spin–valley transport in an asymmetrical MoS2 tunnel junction
Authors: Qiu Xue-Jun , Cao Zhen-Zhou , Hou Jin , Yang Chun-Yong
Published: September 2020

We study the effects of asymmetrical magnetization and an optoelectronic tunable band structure on the transmission of particles in a MoS2 tunnel junction. Based on the results, we propose a model for a multifunctional coupler as a single system incorporating giant magnetoresistance, a spin–valley filter, and a spin–valley valve. The device is made up of ferromagnetic/ferromagnetic/normal junctions, with an off-resonant light and an electric gate potential functioning as the spin–valley filter and spin–valley valve, respectively. Increasing the asymmetrical magnetization is found to substantially enhance the tunneling magnetoresistance (TMR) of the system, leading to giant TMR. The spin–valley filtering is based on the spin imbalance modulation that arises from asymmetrical magnetization and the valley degeneracy breaking of off-resonant light, and the spin–valley valve is produced by altering the effective density of states of spin/valley polarized bands via the gate potential that controls the flow of spin/valley polarized particles. By fixing the magnetization configurations, one specific spin–valley filter and spin–valley valve can be acquired by tuning an external parameter to the corresponding spin/valley polarized energy windows.
On the molecular mechanisms of
α
and
β
relaxations in ionic liquids
Authors: Steinrücken Elisa , Becher Manuel , Vogel Michael
Published: September 2020

Using 2H NMR, we determine correlation times and motional mechanisms for the α and β relaxations of glass-forming imidazolium-based ionic liquids, explicitly, for the associated cation reorientation dynamics. It is shown that the α relaxation is faster, its nonexponentiality is stronger, and the fragility is higher for bis(trifluoromethylsulfonyl)imide anions than that for tetrafluoroborate anions. 2H NMR stimulated-echo studies reveal that the overall reorientation dynamics involved in the α relaxation is isotropic and composed of jumps about small angles, where the mean jump angles are smaller for larger cations. Moreover, we demonstrate that, in addition to a cation-specific β relaxation, all studied ionic liquids exhibit the genuine Johari–Goldstein β relaxation of glass-forming liquids. Various 2H NMR results consistently indicate that the associated rotational motion is spatially highly restricted. Altogether, our findings show that, despite strong electrostatic interaction and prominent microphase separation of ionic liquids, their glassy dynamics resemble that of their nonionic counterparts, including similar microscopic mechanisms for intrinsic α and β relaxations.
Extrinsic voltage control of effective carrier lifetime in polycrystalline PbSe mid-wave IR photodetectors for increased detectivity
Authors: Ganguly Samiran , Tang Xin , Yoo Sung-Shik , Guyot-Sionnest Philippe , Ghosh Avik W.
Published: September 2020

Polycrystalline PbSe for mid-wave infrared (IR) photodetectors is an attractive material option due to its high operating/ambient temperature operation and relatively easy and cheap fabrication process, making it a candidate for low-power, small footprint, uncooled/passively cooled photodetectors. However, there are many material challenges that reduce the specific detectivity (D*) of these detectors. In this work, we demonstrate that it is possible to improve upon this metric by externally modulating the effective lifetime of conducting carriers by application of a back-gate voltage that can control the recombination rate of carriers in the detector by increasing the passivation of PbSe. We build a back-gated PbSe detector, in which we experimentally observe unambiguous signature of effective carrier modulation with a back-gate voltage for different temperatures. We develop a quantitative model for the detector that captures and closely benchmarks this modulation, which is then used to project the increase in D* in better optimized detector designs. This approach when combined with other techniques, such as plasmonic enhancement of light absorption, can lead to substantive enhancement of performance in PbSe mid-wave IR detectors widening their application space.
Adaptive control of transonic buffet flows over an airfoil
Authors: Ren Kai , Chen Yong , Gao Chuanqiang , Zhang Weiwei
Published: September 2020

Flow state can be changed by multiple disturbances and uncertain factors in a complex flow environment, which calls for great interest to adjust the control law automatically to adapt to the changing flow environment. Model-based control can obtain predetermined control effects, but its adaptive ability is limited due to the modeling accuracy and unmodeled dynamics of the reduced-order model. To overcome these limitations, the data-driven adaptive control of transonic buffet flow based on the radial basis function neural network (RBF-NN) is carried out in this work. The actuator is the trailing edge flap, and the feedback signal is the lift coefficient. The historical input and output are used in the RBF-NN adaptive control to calculate the current control input from the neural network. When the flow state changes, the parameters of the neural network are adjusted by an adaptive mechanism to make the system work in an optimal or a near-optimal state automatically. Results show that buffet loads can be suppressed completely by RBF-NN control, even if the freestream Mach number and the angle of attack change continuously [from (M, α) = (0.7, 5.5°) to (M, α) = (0.8, 1.5°)]. The control strategy proposed in this work only needs the historical response data of the flow field, and it shows little dependence on the low-order linear model of the system. Therefore, it can be applied to the unstable flow control, in which the low-order model of the flow is difficult to construct and automatically adapt to the changing flow environment.
Effects of symmetry on magnetohydrodynamic mixed convection flow in a vertical duct
Authors: Belyaev Ivan , Krasnov Dmitry , Kolesnikov Yuri , Biryukov Dmitry , Chernysh Denis , Zikanov Oleg , Listratov Yaroslav
Published: September 2020

Magnetohydrodynamic convection in a downward flow of liquid metal in a vertical duct is investigated experimentally and numerically. It is known from earlier studies that in a certain range of parameters, the flow exhibits high-amplitude pulsations of temperature in the form of isolated bursts or quasi-regular fluctuations. This study extends the analysis while focusing on the effects of symmetry introduced by two-sided rather than one-sided wall heating. It is found that the temperature pulsations are robust physical phenomena appearing for both types of heating and various inlet conditions. At the same time, the properties, typical amplitude, and range of existence in the parametric space are very different at the symmetric and asymmetric heating. The obtained data show good agreement between computations and experiments and allow us to explain the physical mechanisms causing the pulsation behavior.
Dielectric constant of supercritical water in a large pressure–temperature range
Authors: Hou Rui , Quan Yuhui , Pan Ding
Published: September 2020

A huge amount of water at supercritical conditions exists in Earth’s interior, where its dielectric properties play a critical role in determining how it stores and transports materials. However, it is very challenging to obtain the static dielectric constant of water, ϵ0, in a wide pressure–temperature (P–T) range as found in deep Earth either experimentally or by first-principles simulations. Here, we introduce a neural network dipole model, which, combined with molecular dynamics, can be used to compute P–T dependent dielectric properties of water as accurately as first-principles methods but much more efficiently. We found that ϵ0 may vary by one order of magnitude in Earth’s upper mantle, suggesting that the solvation properties of water change dramatically at different depths. Although ϵ0 and the molecular dipole moment increase with an increase in pressure along an isotherm, the dipolar angular correlation has its maximum at 5 GPa–7 GPa, which may indicate that hydrogen bonds become weaker at high pressure. We also calculated the frequency-dependent dielectric constant of water in the microwave range, which, to the best of our knowledge, has not been calculated from first principles, and found that temperature affects the dielectric absorption more than pressure. Our results are of great use in many areas, e.g., modeling water–rock interactions in geochemistry. The computational approach introduced here can be readily applied to other molecular fluids.
Direct numerical simulations of nanoparticle formation in premixed and non-premixed flame–vortex interactions
Authors: Cifuentes Luis , Sellmann Johannes , Wlokas Irenäus , Kempf Andreas
Published: September 2020

Direct numerical simulations (DNSs) of nanoparticle formation in reactive flows are challenging, and only greatly simplified DNS test-cases are possible, which help clarify the turbulence–particle–dynamics interaction and guide the necessary modeling efforts. As a basis for such studies, a new DNS database is introduced, which resolves the smallest relevant scales of the nanoparticle concentration field to obtain insights into the statistics of nanoparticle formation in reactive flows. Formation and evolution of iron oxide nanoparticles in premixed and non-premixed flames wrapped-up by a vortex have been investigated using the sectional model and direct chemistry. The DNSs capture the “engulfing” and local dilution of the particle fields. Different zones of high particle number concentration have been found in every flame, and it was shown that the thickness of these zones decreases with increasing Schmidt number, which confirms that in simulations of nanoparticle-forming turbulent reacting flows, the grid resolution has to be very fine to resolve the characteristic scale for high sections. The contributions to the change in particle concentration due to diffusion, coagulation, and nucleation have been analyzed in detail, and dominant contributions across the particle number concentration layers and across the flames have been identified. This analysis has also been carried out in terms of flat, concave, and convex iso-surface geometries, induced by the flame–vortex interaction and characterized by the curvature of the particle number concentration fields and also by the flame curvature. The results demonstrate that the flame curvature effects cannot be ignored in modeling strategies. The probability density functions for the particle number concentrations have been analyzed and quantified in terms of Shannon information entropy, which illustrates the effect of fast diffusion (and entropy production) of the smaller particles and slow diffusion (and entropy production) of the largest particles with high Schmidt numbers. In addition, the unclosed filtered or averaged agglomeration term was evaluated as a basis for future modeling efforts, showing that agglomeration rates will be underestimated by orders of magnitude unless suitable models are developed.
The effect of current density–voltage measurement conditions on the operational stability of hybrid perovskite solar cells
Authors: Tumen-Ulzii Ganbaatar , Matsushima Toshinori , Klotz Dino , Adachi Chihaya
Published: September 2020

Organic–inorganic lead halide perovskites have attracted great attention for use in solar cells, because of their efficient solar power conversion, along with compatibility with simple solution processing. To evaluate the operational stability of perovskite solar cells (PSCs), measurements on their current density–voltage (J−V) curves are periodically repeated in most literature studies. However, how the periodic J–V measurements affect the operational stability of PSCs has not been well understood to date. In this study, we found that repeating the J−V measurements, especially applying a voltage higher than the open-circuit voltage of PSCs, under continuous illumination, causes serious ion migration, which lowers the operational stability of PSCs. On the other hand, we observed no decrease in operational stability when the applied voltage is close to or lower than the open-circuit voltage of PSCs during the periodic J−V measurements because of the suppressed ion migration. These findings are important in evaluating the intrinsic operational stability of PSCs.
Yielding of cellulose nanocrystal suspensions in the presence of electrolytes
Authors: Danesh Marziyeh , Mauran Damien , Hojabr Sassan , Berry Richard , Pawlik Marek , Hatzikiriakos Savvas G.
Published: September 2020

The rheological properties and yielding behavior of 1 wt. % aqueous sulfonated cellulose nanocrystals (CNCs) in the presence of monovalent (Na+) ions have been investigated. The introduction of more than 20 mM NaCl to the system causes aggregation of neutralized CNCs and leads to the formation of self-similar clusters, which grow in size until they form a three-dimensional network. In the present work, we report a comprehensive study of nonlinear rheology and yielding behavior of CNC/salt gels in steady shear and oscillatory experiments. Two yield stresses have been determined. The first yield stress at low shear rates is attributed to the disconnected CNC clusters as a result of bond breakage. The second yield point occurs at higher shear rates, and it is related to the deformation of clusters, where individual nanorods are nearly separated and dispersed. The existence of these two yield stresses has been identified in both steady-shear scans (high to low and low to high) as well as oscillatory experiments, resulting in consistent results.
Surveying perceptions of the early impacts of an integrated electronic medical record across a hospital and healthcare service
Authors: Eden Rebekah , Burton-Jones Andrew , Staib Andrew , Sullivan Clair
Published: September 2020

ObjectiveThis study provides insights into the reported early impacts of the digital transformation of a large Australian hospital and healthcare service (HHS) by surveying staff perceptions of an integrated electronic medical record (ieMR).
MethodsThe information systems success model was used as a tool to evaluate perceptions of system quality, information quality, individual benefits and expected organisational benefits of the ieMR soon after its introduction at the HHS. A questionnaire was distributed to staff in all five hospitals in the HHS immediately after implementation. Overall staff perceptions were examined, in addition to how perceptions differed by site and profession.
ResultsOverall, staff held mildly positive early perceptions of system quality, information quality, individual benefits and expected organisational benefits. These views were largely consistent across sites. In terms of professions, allied health held more positive perceptions, followed by administrative and nursing professionals. Medical professionals held negative perceptions, but were neutral regarding their future expectations.
ConclusionOn average, staff viewed the ieMR mildly positively immediately after implementation (despite significant changes to work practices), but differences exist across professional groups.
What is known about the topic?Hospitals globally are in the midst of a digital transformation. Yet, reported impacts are mixed and there have been few studies of the effects of comprehensive electronic medical record (EMR) implementations.
What does this paper add?This paper evaluates a comprehensive EMR immediately after go-live. We found positive early perceptions of system quality, information quality, individual benefits and expected organisational benefits. We also found that perceptions of medical professionals were largely negative, but they were neutral in terms of their future expectations.
What are the implications for practitioners?Health services may be unsure of the effect of implementing a comprehensive EMR because of conflicting reports in the literature, some touting major benefits, others stressing major costs. Our results paint a middle-ground picture immediately after implementation. Staff perceptions are mildly positive on average, which is reassuring given the results were obtained during the early disruptive period after implementation.
Effect of dietary supplementation with essential oils and a Bacillus probiotic on growth performance, diarrhoea and blood metabolites in weaned pigs
Authors: Tan B. F. , Lim T. , Boontiam W.
Published: September 2020

Context
Dietary supplementation of essential oils or in combination with a Bacillus probiotic was investigated as an antibiotic growth promoter for weaned pigs.

Aims
To evaluate the effect of essential oils (i.e. thymol and carvacrol mixture) or in combination with a probiotic strain (i.e. Bacillus subtilis PB6) on the growth performance, diarrhoea incidence, ammonia emission and serological profiles of weaned pigs.

Methods
A total of 96 crossbred ([Yorkshire × Landrace] × Duroc) weaned pigs were randomly allotted to one of six treatments based on sex and initial bodyweight. Each group was distributed into four replicates with four pigs each according to a randomised complete block design. The treatments were: (i) positive control, basal diet supplemented with colistin 150 g/tonne and amoxicillin 200 g/tonne; (ii) negative control, basal diet without supplementation; (iii) T3, basal diet supplemented with essential oils 300 g/tonne; (iv) T4, basal diet supplemented with essential oils 600 g/tonne; (v) T5, basal diet supplemented with essential oils 1000 g/tonne; and (vi) T6, basal diet supplemented with essential oils 300 g/tonne diet and Bacillus probiotics 1000 g/tonne.

Key results
The piglets fed with supplements had a significantly higher average daily gain and lower incidence of diarrhoea than the piglets in the negative control (P = 0.001). Feeding the essential oils alone or in combination with probiotics significantly reduced faecal ammonia emission (P = 0.027) and blood urea nitrogen (P = 0.039), while markedly increasing the serum immunoglobulin G concentration of weaned pigs compared with the negative control treatment (P = 0.014). The difference in time of blood collection had significant effects on blood urea nitrogen and immunoglobulins (P = 0.001). However, no significant differences emerged in average daily feed intake, gain: feed ratio, feed efficiency and antibody against swine fever among the treatments.

Conclusions
Diet supplementation with essential oils or in combination with probiotics improved growth performance and immunity, and lowered ammonia emissions and diarrhoea incidence of weaned pigs.

Implications
These findings provide a basis for the application of phytogenic compounds and probiotics as antibiotic growth promoter alternatives in post-weaning diets for pigs.
The value of stubbles and chaff from grain crops as a source of summer feed for sheep
Authors: Thomas Dean T. , Toovey Andrew F. , Hulm Elizabeth , Mata Gonzalo
Published: September 2020

Context
Modern crop stubbles provide an important source of feed for sheep during summer but can vary widely in their feeding value due to Genetics × Environment × Management interactions during crop growth, and how chaff is managed at harvest. Stubbles are difficult to assess for grazing value, due to the heterogeneity of forage components (e.g. stem, leaf, grains), which means that livestock producers rely on their observations and experience to manage sheep grazing stubbles.

Aims
To provide current information on the feeding value of stubbles, and to establish better methods for estimating stubble feeding value.

Methods
In the present paper, we report the results of sheep grazing wheat-stubble paddocks and a survey of the nutritive value of standing stubbles and chaff lines and piles of grain crops (including wheat, barley, canola and lupins) from crop paddocks in the mixed-farming region of Western Australia.

Key results
Without supplementation, wheat stubbles provided 50–100 dry sheep equivalent grazing days per hectare, before the estimated metabolisable energy (ME) intake of sheep fell below maintenance. This was influenced by ewe body condition score, where sheep of lower body condition gained more weight on stubbles (89 g/day higher weight gain per unit lower body condition score). Estimated ME content of edible chaff (leaf, fine stem and seed sheath or pod, excluding main stem and grain) was 5% higher in barley, 19% higher in lupin, and 5% lower in canola, than in wheat chaff, which was 5.9 MJ ME/kg DM.

Implications
While the grazing value of modern stubbles is variable, they have an important role in the seasonal feedbase by providing several months of feed during summer. Chaff by itself does not meet the energy or protein requirements of livestock, so a high-protein grain supplement (e.g. lupins) is necessary to maintain non-lactating ewes fed only chaff. The increased use of chaff lines and piles at harvest, primarily for weed control, provides a new opportunity to fill feed gaps in sheep and cattle enterprises if the material can be transported and stored efficiently, or if grazed in situ, as is common practice.
Victorian maternal and child health nurses’ family violence practices and training needs: a cross-sectional analysis of routine data
Authors: Hooker Leesa , Nicholson Jan , Hegarty Kelsey , Ridgway Lael , Taft Angela
Published: September 2020

This study investigated maternal and child health (MCH) nurse family violence clinical practices, practice gaps and future family violence training needs. Descriptive analysis was conducted of routine data collected as part of a larger MCH nurse family violence training project conducted in 2018. A purposive sample of routine data (2017–18) was analysed from six Victorian metropolitan and four regional and rural areas that were experiencing high rates of violence, as indicated by police reports. Descriptive statistics and regression analyses were used to identify rates of nurse family violence screening, safety planning and referral, with practice differences analysed across locations. MCH nurses ask only one in two clients about family violence at the mandated 4-week postnatal clinic visit. Overall, metropolitan nurses screen for family violence at higher rates than rural nurses. Safety planning rates were low (1.3%), suggesting that screening is not translating to disclosure rates equivalent to state-wide prevalence (~14–17%) or police data. Nurse referrals are even lower (<1%), with practice differences noted across reporting systems. Despite data collection limitations, analysis of routine data shows significant gaps in nurse family violence screening and response practices. This evidence reinforces the need for systems changes to address family violence and other maternal health and social issues.
Managing soil health and crop productivity in potato: a challenging test system
Authors: Powell Shane M. , McPhee John E. , Dean Geoff , Hinton Sue , Sparrow Leigh A. , Wilson Calum R. , Tegg Robert S.
Published: September 2020

Maintaining the health, and therefore productivity, of agricultural soils is vital for continued sustainable agricultural production to support the world’s growing population. Potatoes are grown in a variety of agro-ecological systems and are one of the most important food crops worldwide. Potato crops are demanding on the soil with significant heavy machinery traffic, intensive tillage operations and high inputs of fertiliser, pesticides and water. Maintaining or improving soil health can therefore be challenging for growers. This review considers the different aspects of soil health in a potato production context, how to measure them and how they can be influenced by management practices. Soil health is a complex concept encompassing the physical, chemical and biological properties of the soil and their role in ecosystem services and the growth of plants. Although our understanding of soil health and its impact on crop productivity has improved in the last 30 years, many knowledge gaps remain.
Radical changes in the avifauna of a Sydney suburb, 1971–2014
Authors: Smith Peter , Smith Judy
Published: September 2020

We document changes in the avifauna of Longueville, a residential suburb of Sydney, between 1971–73 and 1977–79 based on daily bird lists, and make comparisons with the present avifauna based on surveys in 2013–14. Of the 31 most common native terrestrial bird species, 17 were ‘decreasers’, present in 1971–73 but not recorded in 2013–14 (although 16 of them were recorded in a large bushland remnant 5 km away), and 14 were ‘increasers’, seven of which were absent or very rare in 1971–73. Eleven species decreased during the 1970s, and six species afterwards. Eight species increased during the 1970s and six species afterwards. The decreasers were predominantly small insectivores and nectarivores. The increasers were of three main types: medium to large carnivores, large frugivores or granivores, and medium-sized nectarivores. Two of the nectarivores, the noisy miner (Manorina melanocephala) and rainbow lorikeet (Trichoglossus haematodus), now dominate the urban bird community of Longueville and are by far the most numerous birds. The increase of both species dates from the late 1970s. The noisy miner is highly aggressive towards other birds and its dramatic increase (it was absent in 1971–73) appears to be the chief cause of the decline of small native birds in Longueville.