bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipid-core/polymer-shell hybrid nanoparticles: synthesis and characterization by fluorescence labeling and electrophoresis
Authors: Bou Sophie , Wang Xinyue , Anton Nicolas , Bouchaala Redouane , Klymchenko Andrey S. , Collot Mayeul
Published: April 2020

New hybrid nanoparticles have been obtained by simple nanoprecipitation using fluorescent labeling of both the oily core (BODIPY) and the polymeric shell (rhodamine) thus allowing the use of electrophoresis to assess their formation and stability.
Speech-Language Pathologists' Comfort Level With Use of Term “Stuttering” During Evaluations
Authors: Byrd Courtney T. , Werle Danielle , St. Louis Kenneth O.
Published: April 2020

Purpose

Speech-language pathologists (SLPs) anecdotally report concern that their interactions with a child who stutters, including even the use of the term “stuttering,” might contribute to negative affective, behavioral, and cognitive consequences. This study investigated SLPs' comfort in providing a diagnosis of “stuttering” to children's parents/caregivers, as compared to other commonly diagnosed developmental communication disorders.

Method

One hundred forty-one school-based SLPs participated in this study. Participants were randomly assigned to one of two vignettes detailing an evaluation feedback session. Then, participants rated their level of comfort disclosing diagnostic terms to parents/caregivers. Participants provided rationale for their ratings and answered various questions regarding academic and clinical experiences to identify factors that may have influenced ratings.

Results

SLPs were significantly less likely to feel comfortable using the term “stuttering” compared to other communication disorders. Thematic responses revealed increased experience with a specific speech-language population was related to higher comfort levels with using its diagnostic term. Additionally, knowing a person who stutters predicted greater comfort levels as compared to other clinical and academic experiences.

Conclusions

SLPs were significantly less comfortable relaying the diagnosis “stuttering” to families compared to other speech-language diagnoses. Given the potential deleterious effects of avoidance of this term for both parents and children who stutter, future research should explore whether increased exposure to persons who stutter of all ages systematically improves comfort level with the use of this term.
Bio‐inspired evolutionary computing approach for distributed active noise control problem
Authors: Kukde Ruchi , Panda Ganapati , Manikandan M. Sabarimalai
Published: April 2020

In this study, a distributed active noise control (DANC) system for spatial noise control in a network of acoustic sensor nodes based on the behavioural traits of felines is presented. An unified strategy based on incremental co‐operative learning and cat swarm intelligence is proposed for noise mitigation in spatial region. The hybrid nature of the proposed incremental cat swarm optimisation (ICSO) algorithm provides efficient noise control without prior estimation of multiple secondary paths. In the developed ICSO‐based DANC scheme, the individual sensor nodes communicate the intermediate solutions using incremental mode of cooperation to attain overall global noise mitigation over the distributed network. The performance of the proposed ICSO based DANC scheme is validated for tonal, broadband and practical air conditioner noise control test scenarios. Evaluation results show that the proposed system achieves faster convergence with computational efficiency of over 36% and ∼2–9 dB improvement in noise cancellation for different noise cases and acoustic environments over genetic algorithm and particle swarm optimisation based DANC counterparts.
Joint optimisation of UAV grouping and energy consumption in MEC‐enabled UAV communication networks
Authors: Zhu Zhengying , Qian Li Ping , Shen Jiafang , Huang Liang , Wu Yuan
Published: April 2020

This study presents a mobile edge computing (MEC)‐enabled UAV communication system, where a number of UAVs are served by terrestrial base stations (TBSs) equipped with computation resource in the non‐orthogonal multiple access manner. Each UAV has to offload its computing tasks to the proper TBS due to the limited energy supply. For this, the authors aim at minimising the sum of transmission energy of UAVs and computation energy of TBSs through jointly optimising the UAV transmit power, computation resource allocation, and UAV grouping. Considering the non‐convexity of this optimisation problem, they obtain the optimal solution in the coupled steps: the convex resource allocation optimisation and the combinatorial UAV grouping optimisation. By exploiting the convex nature of the resource allocation optimisation problem, they obtain the optimal transmit power and computation allocation based on the KKT conditions and the idea of gradient descent method when considering a single TBS. Then, they adopt the simulated annealing to obtain the optimal UAV grouping and TBS selection based on the proposed resource allocation optimisation algorithm. Finally, simulation results show that the proposed joint optimisation of transmit power, computation resource allocation, and UAV grouping can effectively reduce the energy consumption of MEC‐aware UAV communication system.
Affine transformation for synthesis of low sidelobe patterns in planar array antennas with a triangular element grid using the IFT method
Authors: Keizer Will P.M.N.
Published: April 2020

This study deals with the affine transformation that is used to convert the triangular element grid of a planar phased array antenna into a square one. By means of this kind of transformation, it is possible to apply the iterative Fourier transform (IFT) method to synthesise low sidelobe tapers for array antennas featuring a triangular grid. Combination of the IFT method with an affine transformation allows the synthesis of low sidelobe tapers of which the peak sidelobe level does not vary with changing frequency and/or altering main beam position. The considered affine transformation was already briefly addressed in earlier publications of this author. In this study detailed information is given on its use in combination with the IFT method. Examples to demonstrate the effectiveness of the combination affine transformation and the IFT method for triangular grid array antennas are given. It will be shown that the peak sidelobe levels of the obtained tapers are invariant with frequency and scan angle when all far‐field directions of the array factor are involved in the low sidelobe taper synthesis.
Broadband and high gain multilayer multiresonator elliptical microstrip antenna
Authors: Chopra Rinkee , Kumar Girish
Published: April 2020

In this study, a low cost, broadband and high gain multilayer multiresonator microstrip antenna (MSA) is designed. It consists of one metallic fed patch at the bottom layer and two circular patches (1B2 T) are printed on the bottom side of the top FR4 substrate layer, which is air suspended. Two configurations with the bottom patch of circular and elliptical shapes are compared. The elliptical 1B2 T MSA provides better bandwidth (BW), i.e. 53.4% with peak gain of 9.8 dBi. The antenna design parameters are selected to provide maximum BW with uniform gain. The elliptical 1B2 T MSA is further enclosed in a metallic cavity, which improves the BW, gain and front to back (F/B) ratio of the antenna. The elliptical 1B2 T MSA with cavity enclosure is fabricated and tested. Experimental results are in agreement with simulated ones. The elliptical 1B2 T MSA with cavity provides 55.7% BW with peak gain of 12.1 dBi and F/B of >18 dB. The proposed antenna can be used in GPS, 2G, 3G, 4G and Wi‐Fi frequency bands applications.
Tri‐band filtering power divider based on multi‐mode fork‐type resonator for performance enhancement
Authors: Zhang Gang , Zhang Xinde , Liu Shicheng , Tang Liming , Yang Jiquan , Hong Jia‐Sheng
Published: April 2020

A new microstrip tri‐band filtering power divider (FPD) with favourable filtering and isolation performance based on the tri‐mode fork‐type resonator is presented in this study. By constructing the coupling scheme between the input transmission line and two pairs of symmetric fork‐type resonators, a nice tri‐passband filtering power division response can be easily achieved without an additional matching network. Meanwhile, the desired port‐to‐port isolation is attained by elaborately arranging two resistors between the symmetrical resonators with respect to the central input line. To demonstrate the authors’ design concept, one tri‐band FPD prototype is implemented with good agreement between the simulation results of the electromagnetic simulation software and the measurement results of the vector network analyser. Results show that the new tri‐band FPD exhibits sharp roll‐off with five transmission zeros at passband edges, 17.1 dB harmonic suppression up to 4.6 GHz [2.35f0 (f0 = 1.95 GHz)], and better than 15.7 dB in‐band isolation.
Compact high‐isolation planar eight‐way power divider using zero‐phase isolation circuit
Authors: Song Kaijun , Zhao Pan , Chen Yuxuan , Patience Shema Richard
Published: April 2020

A compact high‐isolation planar eight‐way power divider using a zero‐phase isolation circuit is presented. The composite right‐ and left‐handed transmission line is applied to achieve good input impedance matching, and the hybrid coplanar waveguide (CPW)/microstrip line is used to get a compact circuit size in the eight‐way power‐dividing circuit. In addition, the zero‐phase microstrip line is applied to obtain high output isolation. The design has been verified by measurements, which show good agreement with simulations. The fabricated eight‐way power divider measured results show that the central frequency of 2.2 GHz, 15 dB input return loss bandwidth of 36.4%, 0.2 dB insertion loss bandwidth of 29% and 20 dB output isolation bandwidth of 27% are achieved.
Energy‐efficient bi‐directional visible light communication using thin‐film corner cube retroreflector for self‐sustainable IoT
Authors: Chellam Jenila , Jeyachitra Ramasamy Kandasamy
Published: April 2020

This study presents the design and analysis of energy‐efficient visible light communication‐based downlink and uplink using a thin‐film corner cube retroreflector (TCCR). The uplink establishment from the user device (UD) to base station (BS) is achieved with the retroreflection of the downlink light beams using TCCR in UD. It eliminates the requirement of active optical source in the UD that reduces the power consumption for communication from the battery‐constrained devices. Additionally, the photoelectric effect‐based energy harvesting from lighting sources is also incorporated in the UD. By utilising the thin‐film deposition of photosensitive alkali metals Na, K, Rb, and Cs, light energy has been harvested, and the harvested energy is utilised in the UD for the uplink modulation process. It makes the real self‐sustainable communication towards the battery‐less execution of internet of things (IoT). The proposed system offers the downlink and uplink for the distance of 2.15 m with the data rates of 10 Gbps and 1 kbps, respectively. The maximum harvested energy from the 18 W optical source by using the 100 nm Cs‐TCCR is 104.40 µJ, and it can serve the energy consumption of the uplink modulator to transmit the UD data to the BS.
NLTE for APOGEE: simultaneous multi-element NLTE radiative transfer
Authors: Osorio Y. , Allende Prieto C. , Hubeny I. , Mészáros Sz. , Shetrone M.
Published: April 2020

Context.Relaxing the assumption of local thermodynamic equilibrium (LTE) in modelling stellar spectra is a necessary step to determine chemical abundances to better than about 10% in late-type stars.

Aims.We describe our multi-element (Na, Mg, K, and Ca) non-LTE (NLTE) calculations, which can be applied to the APOGEE survey.

Methods.The new version ofTLUSTYallows for the calculation of restricted NLTE in cool stars using pre-calculated opacity tables. We demonstrate thatTLUSTYgives consistent results withMULTI, a well-tested code for NLTE in cool stars. We usedTLUSTYto perform LTE and a series of NLTE calculations that simultaneously used all combinations of one, two, three and four of the elements in NLTE.

Results.We take into account that departures from LTE in one element can affect others through changes in the opacities of Na, Mg, K, and Ca. We find that atomic Mg, which provides strong UV opacity and exhibits significant departures from LTE in the low-energy states, can affect the NLTE populations of Ca, leading to abundance corrections as large as 0.07 dex. The differences in the derived abundances between the single-element and the multi-element cases can exceed those between the single-element NLTE determinations and an LTE analysis. We therefore caution that this is not always a second-order effect. Based on detailed tests for three stars with reliable atmospheric parameters (Arcturus, Procyon, and the Sun), we conclude that our NLTE calculations provide abundance corrections that can in the optical amount to 0.1, 0.2, and 0.7 dex for Ca, Na and K, but LTE is a good approximation for Mg. In theH-band, NLTE corrections are much smaller and always lower than 0.1 dex. The derived NLTE abundances in the optical and in the IR are consistent. In all three stars, NLTE line profiles fit the observations better than the LTE counterparts for all four elements.

Conclusions.The atomic elements in ionisation stages where over-ionisation is an important NLTE mechanism are likely affected by departures from LTE in Mg. Particular care must be taken with the collisions that are adopted for high-lying levels when NLTE profiles of lines in theH-band are calculated. The derived NLTE corrections in the optical and in theH-band differ, but the derived NLTE abundances are consistent between the two spectral regions.
First spectroscopic study of ionised gas emission lines in the extreme low surface brightness galaxy Malin 1
Authors: Junais  , Boissier S. , Epinat B. , Amram P. , Madore B. F. , Boselli A. , Koda J. , Gil de Paz A. , Muños Mateos J. C. , Chemin L.
Published: April 2020

Context. Malin 1 is the largest known low surface brightness (LSB) galaxy, the archetype of so-called giant LSB galaxies. The structure and origin of such galaxies are still poorly understood, especially because of the lack of high-resolution kinematics and spectroscopic data.

Aims. We use emission lines from spectroscopic observations of Malin 1 aiming to bring new constraints on the internal dynamics and star formation history of Malin 1.

Methods. We extracted a total of 16 spectra from different regions of Malin 1 and calculated the rotational velocities of these regions from the wavelength shifts and star formation rates from the observed Hα emission line fluxes. We compared our data with existing data and models for Malin 1.

Results. For the first time we present the inner rotation curve of Malin 1, characterised in the radial range r < 10 kpc by a steep rise in the rotational velocity up to at least ∼350 km s−1 (with a large dispersion), which had not been observed previously. We used these data to study a suite of new mass models for Malin 1. We show that in the inner regions dynamics may be dominated by the stars (although none of our models can explain the highest velocities measured) but that at large radii a massive dark matter halo remains necessary. The Hα fluxes derived star formation rates are consistent with an early-type disc for the inner region and with the level found in extended UV galaxies for the outer parts of the giant disc of Malin 1. We also find signs of high metallicity but low dust content for the inner regions.
Excitation and charge transfer in low-energy hydrogen atom collisions with neutral manganese and titanium
Authors: Grumer J. , Barklem P. S.
Published: April 2020

Data for inelastic processes due to hydrogen atom collisions with manganese and titanium are needed for accurate modeling of the corresponding spectra in late-type stars. In this work excitation and charge transfer in low-energy Mn+H and Ti+H collisions have been studied theoretically using a method based on an asymptotic two-electron linear combination of an atomic orbitals model of ionic-covalent interactions in the neutral atom-hydrogen-atom system, together with the multichannel Landau-Zener model to treat the dynamics. Extensive calculations of charge transfer (mutual neutralization, ion-pair production), excitation and de-excitation processes in the two collisional systems are carried out for all transitions between covalent states dissociating to energies below the first ionic limit and the dominating ionic states. Rate coefficients are determined for temperatures in the range 1000–20 000 K in steps of 1000 K. Like for earlier studies of other atomic species, charge transfer processes are found to lead to much larger rate coefficients than excitation processes.
Role of point and line defects on the electronic structure of LaAlO3/SrTiO3 interfaces
Authors: Gloter Alexandre , Tieri Giulio , Li Danfeng , Caputo Marco , Strocov Vladimir N. , Stéphan Odile , Triscone Jean-Marc , Gariglio Stefano
Published: April 2020

Realization of heterostructures containing multiple two-dimensional electron liquids requires a fine control of the fabrication process. Here, we report a structural and spectroscopy study of LaAlO3/SrTiO3/LaAlO3 trilayers grown on the SrTiO3 substrate by pulsed-laser deposition. Scanning transmission electron microscopy with the help of ab initio calculations reveals that antisite defects associated with oxygen vacancies are primarily present in the SrTiO3 film (STO-f) close to the p-type interface (STO-f/LaAlO3), while oxygen vacancies prevail close to the top n-type interface (LaAlO3/STO-f). At the same interface, misfit dislocations relax the tensile strain of the top LaAlO3 layer. Combining x-ray absorption spectroscopy, x-ray linear dichroism, resonant photoemission spectroscopy, and electron energy loss spectroscopy, we observe that the 3d orbital reconstruction at the interface between LaAlO3 and the SrTiO3 substrate is confined over a few interfacial Ti planes while, at the top n-type interface (LaAlO3/STO-f), the absence of a dichroic signal can be related to the blurring of the interfacial orbital reconstruction due to the heterogeneity of defects.
Aeroacoustics measurement of the gas leakage rate for single hole
Authors: Wang Shen , Yao Xuefeng
Published: April 2020

Gas sealing structures have been widely used in various engineering fields, and the gas leakage rate is one of the most important indicators for evaluating the sealing performance of sealing structures. In this paper, an aeroacoustic measurement method is proposed to measure the gas leakage rate by using one sound pressure sensor based on known location of a single leakage hole combining the aeroacoustic theory with numerical simulation results. First, the basic measurement principle is established using the Lighthill acoustic analogy method. Then, the finite element method is used to calculate the fitting parameters in leakage rate equations. Finally, the single-hole leakage experiments are carried out to verify the effectiveness of this gas leakage rate measurement method. The measurement results are in good agreement with the results recorded by flowmeters.
Effect of shape on liquid–vapor coexistence and surface properties of parallelepiped molecules
Authors: Gutiérrez Anthony B. , Chapela Gustavo A.
Published: April 2020

Liquid–vapor coexistence is calculated via molecular dynamics for a variety of parallelepiped shaped molecules. Models are constructed as an array of tangential hard spheres interacting with an attractive square-well potential. Each shape is formed by varying the number of spheres in their three sides. The initial density of the system is chosen close to the critical density of a SW fluid to obtain an equilibrated liquid–vapor coexistence curve by the process of spinodal decomposition. A pattern that relates the geometry of the molecular models and the existence or non-existence of a liquid–vapor orthobaric curve is shown.
Multicatalytic behavior of Ba0.85Ca0.15Ti0.9 Zr0.1O3 ceramics for pharmaceutical/dye/bacterial treatments
Authors: Sharma Moolchand , Singh Vishvendra Pratap , Kumar Sandeep , Vaish Rahul
Published: April 2020

Multicatalytic activities (photocatalysis, piezocatalysis, and pyrocatalysis) of ferroelectric ceramics Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCZTO) were studied. Maximum degradations (89% and 81%) were achieved in piezo-photocatalytic experiments for degradation of Rhodamine B (RB) and ciprofloxacin. Similarly, 95% degradation of RB was achieved during pyrocatalysis in 250 heating/cooling cycles. Antibacterial performance of ceramics was analyzed with the help of Gram-positive and Gram-negative bacteria-killing processes. The bacterial colony formation drops to zero in 90 min with poled samples of BCZTO ceramics. The poled samples performed much better than that of the unpoled samples in all the catalytic reactions as well as in the bacterial killing process.
Harmonic height distribution in pickup spectroscopy within electrostatic ion beam traps
Authors: Kahana Michal , Musbat Lihi , Nihamkin Maria , Diamant Yael , Piperno Silvia , Ytzhak Shany , Toker Yoni
Published: April 2020

Pickup spectroscopy is a means of determining the abundance, mass, charge, and lifetime of ions oscillating in electrostatic ion beam traps. Here, we present a framework for describing the harmonic height distribution of the Fourier transform of the pickup signal and discuss the importance of the pickup positioning, bunch dynamics, and pickup width on the harmonic height distribution. We demonstrate the methodology using measurements from a newly constructed electrostatic ion beam trap.
First experimental observation of a photoabsorption-edge induced shock by its coalescence onto a regular ablation-shock
Authors: Courtois C. , Poujade O. , Alozy E. , Brygoo S. , Chicanne C. , Chies T. , Darbon S. , Duval A. , Fariaut J. , Ferri M. , Graillot H. , Henry O. , Marchet B. , Masclet-Gobin I. , Seytor P. , Soullie G. , Videau L. , Villette B. , Wrobel R.
Published: April 2020

Implosion experiments of an inertial confinement fusion (ICF) target on the laser megajoule (LMJ) and the National Ignition Facility require, for certain designs, a precise timing coalescence of four shocks at a specific point of the capsule, which strongly depends on the ablator equation of state. In experiments at the Ligne d'Intégration laser facility, a prototype for the LMJ, coalescence of two shocks was studied in a planar polystyrene (CH) sample in an indirect drive configuration. Shocks were driven by x-ray emission generated in a spherical hohlraum radiatively heated using a 12 ns duration laser pulse temporally shaped to produce two steps in the radiation temperature history that launches these two successive ablation-shock waves. Shock velocity was inferred from a Velocity Interferometer System for Any Reflector (VISAR). Shot performed with 10 ns long truncated laser pulses reduces VISAR blanking, which allows us, for the first time to our knowledge, to observe a photoabsorption-edge induced shock, edge-shock for short, which is a third shock out of the two-step radiation temperature history, coalescing with the second ablation shock. The accurate measurement of this shock with well-controlled x-ray drive should potentially help to constrain the equation of state and opacity of carbon in coronal plasma conditions since the behavior of this shock is very sensitive to both. Moreover, since they can drastically alter the speed of coalesced shocks (in keyhole experiments or ignition designs for ICF), measurements of these edge-shocks may also contribute to improving our ICF design capabilities.
First-principles modeling of chemistry in mixed solvents: Where to go from here?
Authors: Maldonado Alex M. , Basdogan Yasemin , Berryman Joshua T. , Rempe Susan B. , Keith John A.
Published: April 2020

Mixed solvents (i.e., binary or higher order mixtures of ionic or nonionic liquids) play crucial roles in chemical syntheses, separations, and electrochemical devices because they can be tuned for specific reactions and applications. Apart from fully explicit solvation treatments that can be difficult to parameterize or computationally expensive, there is currently no well-established first-principles regimen for reliably modeling atomic-scale chemistry in mixed solvent environments. We offer our perspective on how this process could be achieved in the near future as mixed solvent systems become more explored using theoretical and computational chemistry. We first outline what makes mixed solvent systems far more complex compared to single-component solvents. An overview of current and promising techniques for modeling mixed solvent environments is provided. We focus on so-called hybrid solvation treatments such as the conductor-like screening model for real solvents and the reference interaction site model, which are far less computationally demanding than explicit simulations. We also propose that cluster-continuum approaches rooted in physically rigorous quasi-chemical theory provide a robust, yet practical, route for studying chemical processes in mixed solvents.
Investigation of voltage effect on reaction mechanisms in capacitively coupled N2 discharges
Authors: Liang Ying-Shuang , Liu Yong-Xin , Zhang Yu-Ru , Wang You-Nian
Published: April 2020

A systematic investigation of voltage effect on the plasma parameters, especially the species densities and chemical reaction mechanisms, in the capacitive N2 discharges is performed by employing a two-dimensional self-consistent fluid model. The validity of the numerical model is first demonstrated by the qualitative agreement of the calculated and experimental results. Then, the densities, production mechanisms, and loss mechanisms of species from simulation are examined at various voltages. It is found that all the species densities increase monotonically with the voltage, whereas their spatial profiles at lower voltages are quite different from those at higher voltages. The electrons and N2+ ions are mainly generated by the electron impact ionization of N2 gas, while the N+ ions, whose density is one or two orders of magnitude lower, are mostly formed by the ionization of N atoms. The electron impact dissociation of N2 gas dominates the generation of N atoms, which are mostly destroyed for the N+ ion production. As for the excited N2 levels, the level conversion processes play a very important role in their production and depletion mechanisms, except for the electron impact excitation of the ground state N2 molecules.
Numerical study on reflection of an oblique detonation wave on an outward turning wall
Authors: Wang Kuanliang , Zhang Zijian , Yang Pengfei , Teng Honghui
Published: April 2020

Oblique detonation waves (ODWs) have been studied widely as the basis of detonation-based hypersonic engines, but there are few studies on ODWs in a confined space. This study simulates ODW reflection on a solid wall before an outward turning corner for a simplified combustor–nozzle flow based on a two-step kinetic model. Numerical results reveal three types of ODW structures: stable, critical, and unstable. When the reflection occurs at the turning point, the stable ODW structure remains almost the same as before reflection. When the wave reflects at the wall before the turning point, either the critical structure or the unstable structure arises, which has never been investigated before. Both structures have the same initial two-section detonation surface: but the critical one becomes stationary at a certain position, while the unstable one keeps traveling upstream. By adjusting the location of the expansion wave and degree of the turning angle, the difference of the two structures is attributed to the thermal choking appearing only in the unstable structure. The thermal choking is achieved by the merging of subsonic zones, whose dependence on the various parameters is discussed.
ZnTe-based photocathode for hydrogen evolution from water under sunlight
Authors: Minegishi Tsutomu , Ohnishi Atsushi , Pihosh Yuriy , Hatagami Kentaro , Higashi Tomohiro , Katayama Masao , Domen Kazunari , Sugiyama Masakazu
Published: April 2020

Zinc telluride (ZnTe)-based photocathodes with appropriate modifications showed incident-photon-to-current conversion efficiencies (IPCEs) higher than 30% at 420–520 nm, reached 40% IPCE at 460 nm, and were not zero up to 710 nm because of photoexcitation related to the intermediate-band. ZnTe films were prepared by productive close-spaced sublimation. After surface modification with CdS and Pt, the photocathode showed clear cathodic photoresponse in the phosphate buffer solution. The modulation of substrate temperature, incorporation of Cu, and further surface modification with very thin Mo and Ti layers significantly enhanced cathodic photocurrent which contributes to hydrogen evolution from water. Through the measurement of IPCEs, photoelectrochemical hydrogen evolution from water utilizing photoexcitation related to the intermediate-band was first confirmed. The photocathode showed advantageous durability under simulated sunlight: during irradiation of about 50 min, the stabilized photocurrent slightly decreased from 1.6 mA cm−2 to 1.5 mA cm−2.
Evolving structure–property relationships in metals with nonequilibrium concentrations of vacancies
Authors: Adibi Sara , Wilkerson Justin W.
Published: April 2020

Here, we use molecular dynamics simulations as a tool to investigate vacancy clustering in pure aluminum single crystals. A 1% superconcentration of single vacancies are randomly introduced into an otherwise perfect lattice, and the system is allowed to evolve for 500 ns at an elevated temperature of 728 K. Under these conditions, the individual vacancies rapidly agglomerate into larger clusters to reduce their overall energy. The systems are then subject to mechanical deformation to failure. The results of a total of 35 molecular dynamics simulations are reported. The mechanical behavior of these systems is found to be highly sensitive to the vacancy cluster microstructure, with the largest cluster size being most closely correlated with the cavitation strength. Since the largest cluster size evolves, an interesting time–structure–property coupling governs the behavior of these supersaturated metals. Despite the idealizations of the microstructure and loading conditions, we find a remarkably favorable agreement with laser-driven spall experiments.
X-ray characterization of the Icarus ultrafast x-ray imager
Authors: Looker Quinn , Colombo Anthony P. , Kimmel Mark , Porter John L.
Published: April 2020

Ultrafast x-ray imagers developed at Sandia National Laboratories are a transformative diagnostic tool in inertial confinement fusion and high energy density physics experiments. The nanosecond time scales on which these devices operate are a regime with little precedent, and applicable characterization procedures are still developing. This paper presents pulsed x-ray characterization of the Icarus imager under a variety of illumination levels and timing modes. Results are presented for linearity of response, absolute sensitivity, variation of response with gate width, and image quality.
ScAlN/3C-SiC/Si platform for monolithic integration of highly sensitive piezoelectric and piezoresistive devices
Authors: Qamar Afzaal , Phan Hoang-Phuong , Dinh Toan , Nguyen Nam-Trung , Rais-Zadeh Mina
Published: April 2020

This paper reports on a platform for monolithic integration of piezoelectric and piezoresistive devices on a single chip using the ScAlN/3C-SiC/Si heterostructure. Surface acoustic wave devices with an electromechanical coupling of 3.2% and an out-of-band rejection as high as 18 dB are demonstrated using the excellent piezoelectric properties of ScAlN and low acoustic loss of 3C-SiC. Additionally, a large piezoresistive effect in the low-doped n-type 3C-SiC(100) thin film has been observed, which exceeds the previously reported values in any SiC thin films. The growth of the n-type 3C-SiC thin film was performed using the low pressure chemical vapor deposition technique at 1250 °C and the standard micro-electro-mechanical systems process is used for the fabrication of 3C-SiC piezoresistors. The piezoresistive effect was measured using the bending beam method in different crystallographic orientations. The maximum gauge factor is –47 for the longitudinal [100] orientation. Using the longitudinal and transverse gauge factors for different crystallographic orientations, the fundamental piezoresistive coefficients of the low-doped n-type 3C-SiC thin film are measured to be π11=(−14.5±1.3)×10−11 Pa−1,  π12=(5.5±0.5)×10−11 Pa−1, and π44=(−1.7±0.7)×10−11 Pa−1.
Particle beams behind physics discoveries
Authors: Shiltsev Vladimir
Published: April 2020

Advances in accelerator technology are enabling discoveries in particle physics and other fields.
Mechanical properties of soybean plants under various plant densities
Authors: Xu Yao , Zhang Rui , Hou Zhaofang , Yan Chao , Xia Xuan , Ma Chunmei , Dong Shoukun , Gong Zhenping
Published: April 2020

Lodging can reduce grain yield and quality, especially in crops planted at high densities. Force analysis, which relates stem mechanical properties and morphological characteristics under high densities, was used to study lodging in soybean (Glycine max (L.) Merr.). We applied mechanical lodging and examined the relationships between stem bending moment of the breaking force and morphological characteristics in two soybean varieties of contrasting heights grown at four crop population densities (200000, 300000, 400000 and 500000 plants ha–1). The experiment was performed in a split-plot design during 2015–16. Measurements were made during the R1–R8 growth stages. Results showed that the full seed stage was the most sensitive period for lodging. Stem strength of the soybean plants increased with growth and development; however, during the R5–R6 stages, the weakened degree of stem strength was greater than the gravity moment. This was the primary reason for the soybeans tending to lodge during this period. In addition, increasing the planting density weakened the mechanical properties significantly. During breeding efforts to improve the soybean lodging resistance, more attention should be paid to strengthening soybean stems. This study also showed that the ratio of stem diameter to plant height could be a new quantitative index for evaluating the lodging resistance of soybeans.
Genome-wide association mapping and candidate gene analysis for water-soluble protein concentration in soybean (Glycine max) based on high-throughput single nucleotide polymorphism markers
Authors: Sui Meinan , Wang Yue , Cui Zhihui , Teng Weili , Yuan Ming , Li Wenbin , Wang Xi , Li Ruiqiong , Lv Yan , Yan Ming , Quan Chao , Zhao Xue , Han Yingpeng
Published: April 2020

Water-soluble protein concentration (WSPC) of soybean (Glycine max (L.) Merrill) is an important factor affecting the quality of soybean-derived food and the aesthetic appearance of soybean products. In the present study, a representative soybean population of 178 elite accessions was used to determine quantitative trait nucleotides of WSPC via a genome-wide association study (GWAS). In total, 33149 single-nucleotide polymorphisms (SNPs) with minor allele frequencies ≥5% and missing data ≤10% were applied in assessing the level of linkage disequilibrium. Finally, three association signals were identified related with WSPC through GWAS, including one novel locus and two known loci that overlapped the genomic region of reported quantitative trait loci. Thirty candidate genes located in the 200-kb genomic region of each peak SNP were detected and mainly grouped into the classes of protein synthesis/modification/degradation, RNA regulation of transcription, amino acid synthesis/metabolism, transport, hormone metabolism, signalling, development, lipid metabolism, and secondary metabolism. Through a gene-based association, 21 SNPs from eight genes were detected. Among them, four genes have been recognised as significant factors in mediating WSPC. The loci identified with beneficial alleles and candidate genes may be of great value for further functional analysis and marker-assisted selection of WSPC in soybean.
Surface optical reflectance combined with x-ray techniques during gas-surface interactions
Authors: Albertin S , Gustafson J , Zhou J , Pfaff S , Shipilin M , Blomberg S , Merte L R , Gutowski O , Dippel A-C , Zetterberg J , Lundgren E , Hejral U
Published: April 2020

High energy surface x-ray diffraction (HESXRD), x-ray reflectivity (XRR), mass spectrometry (MS) and surface optical reflectance (SOR) have been combined to simultaneously obtain sub-second information on the surface structure and morphology from a Pd(100) model catalyst during in situ oxidation at elevated temperatures and pressures resulting in Pd bulk oxide formation. The results show a strong correlation between the HESXRD and SOR signal intensities during the experiment, enabling phase determination and a time-resolved thickness estimation of the oxide by HESXRD, complemented by XRR measurements. The experiments show a remarkable sensitivity of the SOR to changes in the surface phase and morphology, in particular to the initial stages of oxidation/reduction. The data imply that SOR can detect the formation of an ultrathin PdO surface oxide layer of only 2–3 Å thickness.
Investigating conditional GAN performance with different generator architectures, an ensemble model, and different MR scanners for MR-sCT conversion
Authors: Fetty Lukas , Löfstedt Tommy , Heilemann Gerd , Furtado Hugo , Nesvacil Nicole , Nyholm Tufve , Georg Dietmar , Kuess Peter
Published: April 2020

Recent developments in magnetic resonance (MR) to synthetic computed tomography (sCT) conversion have shown that treatment planning is possible without an initial planning CT. Promising conversion results have been demonstrated recently using conditional generative adversarial networks (cGANs). However, the performance is generally only tested on images from one MR scanner, which neglects the potential of neural networks to find general high-level abstract features. In this study, we explored the generalizability of the generator models, trained on a single field strength scanner, to data acquired with higher field strengths. T2-weighted 0.35T MRIs and CTs from 51 patients treated for prostate (40) and cervical cancer (11) were included. 25 of them were used to train four different generators (SE-ResNet, DenseNet, U-Net, and Embedded Net). Further, an ensemble model was created from the four network outputs. The models were validated on 16 patients from a 0.35T MR scanner. Further, the trained models were tested on the Gold Atlas dataset, containing T2-weighted MR scans of different field strengths; 1.5T(7) and 3T(12), and 10 patients from the 0.35T scanner. The sCTs were dosimetrically compared using clinical VMAT plans for all test patients. For the same scanner (0.35T), the results from the different models were comparable on the test set, with only minor differences in the mean absolute error (MAE) (35-51HU body). Similar results were obtained for conversions of 3T GE Signa and the 3T GE Discovery images (40-62HU MAE) for three of the models. However, larger differences were observed for the 1.5T images (48-65HU MAE). The overall best model was found to be the ensemble model. All dose differences were below 1%. This study shows that it is possible to generalize models trained on images of one scanner to other scanners and different field strengths. The best metric results were achieved by the combination of all networks.
Fingerprints of external forcings on Sahel rainfall: aerosols, greenhouse gases, and model-observation discrepancies
Authors: Marvel Kate , Biasutti Michela , Bonfils Céline
Published: April 2020

Over the 20th and 21st centuries, both anthropogenic greenhouse gas increases and changes in anthropogenic aerosols have affected rainfall in the Sahel. Using multiple characteristics of Sahel precipitation, we construct a multivariate fingerprint that allows us to distinguish between the model-predicted responses to greenhouse gases and anthropogenic aerosols. Models project the emergence of a detectable signal of aerosol forcing in the middle of the 20th century and a detectable signal of greenhouse gas forcing at the beginning of the 21st. However, the signals of both aerosol and greenhouse gas forcing in observations emerge earlier and are stronger than in the models, far stronger in the case of aerosols. The similarity between the response to aerosol forcing and the leading mode of internal variability makes it difficult to attribute this model-observation discrepancy to errors in the forcing, errors in the forced response, model inability to capture the amplitude of internal variability, or some combination of these. For greenhouse gases, however, the forced response is distinct from internal variability as estimated by models, and the observations are largely commensurate with the model projections.
Cellulose conversion into renewable chemicals and fuels over supported metal catalysts
Authors: Hassan N S , Jalil A A
Published: April 2020

Nowadays, the development of biomass as an alternative energy source has been explored for the production of energy, chemicals and transportation fuels. Cellulose is an abundant, low-cost and renewable energy source that can be transformed into solid, liquid and gas products by pyrolysis. Sustainable, low cost and efficient catalysts are needed for catalytic cellulose conversion by pyrolysis. Among heterogeneous catalysts, supported metal catalysts have been extensively studied which demonstrated distinct reactivity and/or selectivity in a variety of chemical reactions. This paper reviews and provides a summary of the cellulose conversion by supported metal catalysts into value added chemicals and fuels. Emphases will be put on the reaction mechanism and key factors that exert effect on the catalytic performance.
Shape selective alkylation of benzene with methanol over different zeolite catalysts
Authors: Rahman A F A , Jalil A A , Jusoh N W C , Mohamed M , Fatah N A A , Hambali H U
Published: April 2020

Benzene methylation is an important process for removing excess benzene in petrochemical industries to produce value-added products such as toluene and xylene. In this study, the performance of three types of zeolites, which is ZSM-5 (HZ), zeolite Y (HY) and zeolite β (Hβ) were investigated as catalyst in the benzene methylation reaction. The catalysts were characterized by N2 adsorption-desorption and FTIR. The N2 adsorption-desorption verified that the mesopores volume of the catalysts was in the following order: HB > HY > HZ. While, the FTIR-lutidine revealed that the HB possessed the highest amount of Brönsted acid sites followed by HZ and HY. The catalytic testing at 573 K showed that HZ gave good performance in benzene methylation with 55.2% and 22.1% yield of toluene and xylene, respectively. It is suggested that HZ catalyst with moderate amount of Brönsted acid sites and smallest mesopores volume appear to be effective for shape selective synthesis of toluene and xylene. In addition, pore structure of HZ also contributed to the high catalytic activity of benzene methylation.
Dendritic Mesoporous Ni/KCC-1 for Partial Oxidation of Methane to Syngas
Authors: Siang T J , Jalil A A , Hambali H U , Abdulrasheedand A A , Azami M S
Published: April 2020

Depletion of fossil fuel for global energy system and increasing concern on global warming have driven the exploration of alternative and sustainable energy source in realms of academia and industry. This study aims to investigate the physicochemical features of KAUST Catalysis Center-1 supported catalyst (i.e., Ni/KCC-1) and evaluate its catalytic performance for Partial Oxidation of Methane (POM) reaction. N2 physisorption and XRD analyses confirmed the structural integrity of KCC-1 framework after NiO addition while the growth of Si–O–Ni bonds in KCC-1 structure was corroborated by the FTIR results. The FESEM and TEM images for KCC-1 not only affirm the successful formation of bicontinuous lamellar morphology but also reveal that the three-dimensional spherical structure was originally developed from the centre of microsphere into all axial. The combustion-reforming pathway was determined during reaction run and the H2/CO ratio ranging of 1.48 to 2.14 was appropriate for synthetic fuel production via Fischer-Tropsch synthesis (FTS).
Bayesian Analysis for Assessing Risks of Rotating Equipment and Its Financial Loss
Authors: Oktarinanda Rifky , Norazahar Norafneeza
Published: April 2020

The petrochemical industry is equipped with major and rotating equipment, such as storage tanks and pumps, to produce the required outputs. The equipment could pose a high level of risks should the organization failed to provide control and mitigation measures. Risk analysis is a conventional and practical technique in identifying hazards and assessing risks associated with equipment. The risk analysis can be integrated with the Bayes’s theorem to assess risks of major and rotating equipment. Therefore, this paper presents the use of Bayesian analysis for assessing risks of rotating equipment and its financial loss, specifically in the petrochemical industry. The study begins with developing a cause-and-effect relationship using a Bayesian network. The probability of failure of equipment and its financial loss can be analyzed based on the Bayesian network. The cause-and-effect relationship could also reveal human factors contributing to the probability of failure of equipment. This paper focuses on an accident involving pumps during maintenance activity in the petrochemical plant. The human factors issues contributing to the accident and the financial loss are inadequate procedures and poor work processes.
A Community-Based Emergency Response Management in Pasir Gudang, Johor: Theoretical Framework
Authors: Ahmad Noor Afzan , Kidam Kamarizan , Mohsin Rahmat
Published: April 2020

Community-based emergency response management refers to a collaborative planning and engagement approach, which is designed to support communities and organizations in developing a safer, more resilient and sustainable future. That being mentioned, this study looked into the theoretical bases and practices in light of emergency response, apart from determining the functions of the community in line with emergency response. The primary goal of this study is to build a theoretical framework that enhances the functions of the community in times of emergency response. The mixed-method approach was adopted for data collection. The qualitative approach via interviews had been performed with organization and industry experts in Pasir Gudang, while the quantitative method was employed for the residents in Pasir Gudang. The theoretical framework embeds six elements of emergency response for the community to improve its emergency management. The identified community-based functions seemed to lack in activities, action, function, technique, knowledge, and skill. The proposed theoretical framework is bound to aid the management to comprehend the essence of community-based emergency response and to implement viable strategies in times of emergency.
The Verification result of Permit to Work Assessment in Occupational Accident using Fault Tree Analysis
Authors: Jusoh Nizar , Ali Mohamad Wijayanuddin , Tuan Abdullah Tuan Amran , Husain Alias
Published: April 2020

The objective of this paper is to elaborate and verified the results of the Permit To Work assessment that has been conducted using the Structural Equation Model (SEM) with Fault Tree Analysis (FTA) technique. The author used the Fault Tree Analysis to verify the result of five PTW elements i.e. Hazardous Activity, Worksite Inspection, Supporting Document, Work Description and Close Out. As it is known, the FTA is used to find the probability and cause of an accident or “Top Event”. FTA is a relatively well-known technique used to find the probability of system failure. After the analysis using FTA technique, it was found that all the results of SEM and FTA gives the similar rank to Occupational Accident which is indicated that the result is correct and acceptable for this study. This is Part II of two paper, focusing on PTW Assessment result validation using Fault Tree Analysis.