bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal deflection in neutron scattering sample environments at Oak Ridge National Laboratory
Authors: Quirinale D. G. , Stevens E. , Zhang Y. , Mills R. A. 
Published: May 2024

The neutron sources at Oak Ridge National Laboratory use a wide suite of sample environment equipment to deliver extreme conditions for a number of experiments. Much of this instrumentation focuses on extremes of temperature, such as cryostats, closed-cycle refrigerators in both low and high temperature configurations, and radiant heating furnaces. When the temperature is controlled across a large range, thermal deflection effects can notably move the sample and affect its alignment in the beam. Here, we combine these sample environments with neutron imaging and machine vision to determine the motion of a representative sample with respect to the neutron beam. We find vertical sample displacement on the order of 1–2 mm and horizontal displacement that varies from near-negligible to 1.2 mm. While these deflections are not relevant for some of the beamlines at the first target station at the spallation neutron source and the high flux isotope reactor, they will become critical for upcoming instrumentation at the second target station, as well as any instruments targeting sub-mm samples, as neutron sources and optics evolve to smaller and more focused beams. We discuss mitigation protocols and potential modifications to the environment to minimize the effect of misalignment due to thermal deflection.
Extended short-wave infrared high-speed all-GeSn PIN photodetectors on silicon
Authors: Atalla M. R. M. , Lemieux-Leduc C. , Assali S. , Koelling S. , Daoust P. , Moutanabbir O. 
Published: May 2024

There is an increasing need for silicon-compatible high-bandwidth extended-short wave infrared (e-SWIR) photodetectors (PDs) to implement cost-effective and scalable optoelectronic devices. These systems are quintessential to address several technological bottlenecks in detection and ranging, surveillance, ultrafast spectroscopy, and imaging. In fact, current e-SWIR high-bandwidth PDs are predominantly made of III–V compound semiconductors and thus are costly and suffer a limited integration on silicon besides a low responsivity at wavelengths exceeding 2.3 μm. To circumvent these challenges, Ge1−xSnx semiconductors have been proposed as building blocks for silicon-integrated high-speed e-SWIR devices. Herein, this study demonstrates vertical all-GeSn PIN PDs consisting of p-Ge0.92Sn0.08/i-Ge0.91Sn0.09/n-Ge0.89Sn0.11 and p-Ge0.91Sn0.09/i-Ge0.88Sn0.12/n-Ge0.87Sn0.13 heterostructures grown on silicon following a step-graded temperature-controlled epitaxy protocol. The performance of these PDs was investigated as a function of the device diameter in the 10–30 μm range. The developed PD devices yield a high bandwidth of 12.4 GHz at a bias of 5 V for a device diameter of 10 μm. Moreover, these devices show a high responsivity of 0.24 A/W, a low noise, and a 2.8 μm cutoff wavelength, thus covering the whole e-SWIR range.
Collective dynamics of liquid sulphur across the polymerisation transition temperature probed by inelastic x-ray scattering
Authors: Hosokawa Shinya , Katayama Yoshinori , Tsutsui Satoshi , Baron Alfred Q R 
Published: May 2024

AbstractInelastic x-ray scattering (IXS) experiments on liquid sulphur were carried out below (140 ∘C) and above (180 ∘C) the polymerisation temperatureTλof about 159 ∘C to investigate changes in the collective dynamics of this unique liquid, that exhibits a liquid–liquid transition. As reported earlier, broad longitudinal acoustic excitation signals were observed at both temperatures, and only the width of the quasielastic peaks slightly decreased when the temperature crossed the transition temperature. A model analysis was performed using a generalised Langevin formalism with a memory function having one thermal and two viscoelastic decay channels with the help of simple sparse modelling, and large positive deviations from the hydrodynamic sound velocity by 51%–54% were observed. The fast viscoelastic relaxation timeτµis close to the correlation times of intermolecular stretching and bending motions of local sulphur connections in both ring and chain structures, and is similar to those of other molecular liquids. The small contrasts in the IXS spectra across theλtransition result in large changes in only the slow viscoelastic decay timeταof the memory function. Theταvalue at 140 ∘C matches the mixed internal/external torsional modes of S8molecules well, whereas that at 180 ∘C has no corresponding molecular motion mode. The kinematic viscosity values at theQ→0limit are much smaller than the minimum values of macroscopic shear viscosity, indicating that large changes in relaxation dynamics are expected withQin the GHz and MHz excitation regimes.
A modified two temperature molecular dynamics (2T-MD) model for cascades
Authors: Rojano Andrés , Hunt R J , Crocombette J-P , Murphy S T 
Published: May 2024

Abstract
Two-Temperature molecular dynamics (2T-MD) is a common approach for describing how electrons contribute to the evolution of a damage cascade by addressing their role in the redistribution of energy in the system. However, inaccuracies in 2T-MD’s treatment of the high-energy particles have limited its utilisation. Here, we propose a reformulation of the traditional 2T-MD scheme to overcome this limitation by addressing the spurious double-interaction of high-energy atoms with electrons. We conduct a series of radiation damage cascades for 30, 50, and 100 keV primary knock-on atoms in increasingly large cubic W cells. In the simulations, we employ our modified 2T-MD scheme along with other treatments of electron–phonon coupling to explore their impact on the cascade evolution and the number of remnant defects. The results suggest that with the proposed modification, 2T-MD simulations account for the temperature time evolution during the ballistic phase and remove arbitrary choices, thus providing a better description of the underlying physics of the damage process.
Pendulum with a large bob
Authors: Tadta Kritsada , Tanalikhit Pattarapon , Kanchanapusakit Wittaya 
Published: May 2024

Abstract
By measuring the period of oscillations, a suspended bob is used to determine the local gravitational acceleration g. When modelling the system as either a simple pendulum or a physical pendulum, the measured g is found to be less than the accepted value as the size of the bob increases. With a given bob’s size, the simple pendulum measures g to be slightly higher than the physical pendulum does.
Ultrabright attosecond gamma ray from irradiating solid foil with tailored vortex laser pulse
Authors: Ju L B , Wu C N , Li R , Zhang H , Wu S Z , Yu M Y , Huang T W , Zhou C T , Ruan S C 
Published: May 2024

Abstract
Intense attosecond light sources are required for investigating ultrafast electron dynamics, such as that in molecules and atoms, etc. However, so far the achievable photon energy remains at the keV level, thereby limiting their range of applications. For instance, probing intranuclear dynamics requires photon energies in the gamma-ray regime. We propose here a scheme for generating intense attosecond gamma-ray pulses by irradiating a thin solid-density foil with intense vortex laser. In the interaction, the laser driven-foil electrons are differentially accelerated within a quarter-wave field and become highly bunched. Three-dimensional particle-in-cell simulations show that they can efficiently (with

∼

30
%

energy conversion efficiency) radiate ultrashort (

∼

400

as), high-flux (

>

10

10

photons per pulse), and ultrabrilliant (up to 1027 photons s−1 mm−2 mrad−2 per 0.1% BW at 1 MeV photon energy) gamma rays. With an x-ray driving laser, the scheme can even produce isolated bright sub-attosecond gamma-ray pulses that are useful for time-resolved nuclear spectroscopy and many other areas.
Comparing the efficiency of fly ash geopolymer attenuation and cement mortar as diagnostic x-ray shielding materials through theory and experiment
Authors: Shalbi Sabri M , Oglat Ammar A , Jaafar M S , Ahmed Naser M 
Published: May 2024

Abstract
This study compared ordinary Portland cement (OPC) and Fine Aggregate Graded Polymer (FAGP) samples mixed with 0%, 5%, 10%, and 15% barium sulfate (BaSO4). Theory using the XCOM program and experiments using x-ray fluorescence (XRF) within a specified energy range of 16–25 keV were used to calculate the samples’ mass attenuation coefficients. The comparison involved calculating the linear attenuation coefficients (μ/ρ) and attenuation coefficients (μ) of the samples. Both theoretical and experimental results show that the FAGP containing 15% BaSO4 at 16.61 keV has the best attenuation. The findings show that BaSO4 improves radiation shielding. A negative association was found between the attenuation coefficient (μ) and the energy level of radiated radiation. The analysis also found significant concordance between experimental and theoretical methods. In conclusion, the XCOM program had slightly higher mass attenuation coefficients, especially at lower energy levels.
Epitaxial analysis of GaInP/AlGaInP red light-emitting diodes with ternary AlGaP quantum barriers for quantum efficiency enhancement
Authors: Anum  , Usman Muhammad , Habib Usman , Ali Shazma 
Published: May 2024

Abstract
We have numerically analyzed Gallium Indium Phosphide (GaInP)/Aluminum Gallium Indium Phosphide (AlGaInP) red light-emitting diodes (LEDs) by utilizing ternary Aluminum Gallium Phosphide (AlGaP) quantum barriers instead of the conventional quaternary AlGaInP quantum barriers. The simulation findings show that the use of AlGaP quantum barriers in AlGaInP red light-emitting diodes leads to a significant increase in both electron and hole concentration in the quantum wells which in turn enhances the rate of radiative recombination compared to conventional (reference) red light-emitting diodes. Furthermore, the proposed LEDs have a substantial decline in efficiency droop from 38% to 32%.
Measurement of the damping coefficient of an elastic rubber band oscillator by a smartphone
Authors: Agliolo Gallitto Aurelio , Battaglia Onofrio Rosario , Fazio Claudio 
Published: May 2024

Abstract
The use of smartphones as laboratory tools for school physics experiments has recently received attention for the possibility of carrying out a wide variety of didactic experiments with low-cost equipments. This article presents a study on a damped oscillator consisting of an elastic rubber loop and a mass. The investigation of the oscillations was conducted by using a smartphone. The experimental data was interpreted by a simple model, obtaining information on the viscoelastic properties of the rubber material.
Quantum support vector machine for multi classification
Authors: Xu Li , Zhang Xiao-yu , Li Ming , Shen Shu-qian 
Published: May 2024

Abstract
Classical machine learning algorithms seem to be totally incapable of processing tremendous data, while quantum machine learning algorithms could deal with big data unhurriedly and provide exponential acceleration over classical counterparts. In this paper, we propose two quantum support vector machine algorithms for multi classification. One is the quantum version of the directed acyclic graph support vector machine. The other one is to use the Grover search algorithm before measurement, which amplifies the amplitude of the phase storing of the classification result. For k classification, the former provides quadratic reduction in computational complexity when classifying. The latter accelerates the training speed significantly and more importantly, the classification result can be read out with a probability of at least 50% using only one measurement. We conduct numerical simulations on two algorithms, and their classification success rates are 96% and 88.7%, respectively.
RFX-mod2 diagnostic capability enhancements for the exploration of multi-magnetic-configurations
Authors: Carraro L. , Zuin M. , Abate D. , Agostinetti P. , Agostini M. , Aprile D. , Barbisan M. , Belpane A. , Berton G. , Bonotto M. , Brombin M. , Cavazzana R. , Cinnirella L. , Ciufo S. , Croci G. , Cordaro L. , D’Isa F. , Dal Bello S. , Dal Molin A. , De Masi G. , Emma G. , Fadone M. , Fassina A. , Fiorucci D. , Franz P. , Grando L. , Guiotto F. , La Matina M. , Marchiori G. , Marconato N. , Mario I. , Marrelli L. , Milazzo R. , Molisani S. , Moresco M. , Muraro A. , Perelli Cippo E. , Peruzzo S. , Porcu P. , Pomaro N. , Puiatti M.E. , Putignano O. , Rigamonti D. , Rigoni Garola A. , Rizzolo A. , Ruffini F. , Scarin P. , Spagnolo S. , Spolaore M. , Taliercio C. , Tardocchi M. , Terranova D. , Ugoletti M. , Valisa M. , Vianello N. , Zaniol B. 
Published: May 2024

Abstract
The RFX-mod2 device, the upgraded version of the previous RFX-mod with a modified magnetic boundary, is presently under realization and will start to be operated in 2025. Significant upgrades of the diagnostic capabilities have been proposed and are under development. These include a largely increased number of in-vessel magnetic and electrostatic sensors, a new fast reciprocating manipulator for the exploration of the edge plasma in a wide range of experimental conditions, the improved Thomson scattering and soft x-ray diagnostics system for a detailed determination of the behavior of the electron temperature profile, new dedicated systems for the space and time resolved analysis of x-ray spectra and neutron rate, a reflectometric diagnostic for real-time determination of plasma position, two diagnostics devoted to the imaging of light impurities and influxes behavior along with arrays of halo current sensors. These diagnostic upgrades will be accompanied by a significant effort to improve the control of the electron density and of the impurity influxes by means of proper treatment of plasma facing components with in-vessel fixed electrodes distributed over the first wall. The described advancements will allow a deeper understanding of physics phenomena in the wide variety of magnetic configurations, including the tokamak, the reversed-field pinch and the Ultra-low q, which can be produced in RFX-mod2 thanks to its flexibility and unique MHD control capabilities.
Automated W7-X sawtooth crashes detection and characterization
Authors: Zanini M. , Aymerich E. , Böckenhoff D. , Merlo A. , Aleynikova K. , Brandt C. , Braune H. , Brunner K.J. , Hirsch M. , Höfel U. , Knauer J. , Laqua H.P. , Marsen S. , Pavone A. , Rahbarnia K. , Schilling J. , Smith T. , Stange T. , Thomsen H. , Wolf R.C. , Zocco A. ,   W7-X Team
Published: May 2024

Abstract
Sawtooth crashes are observed during ECCD experiments at the superconducting optimized stellarator Wendelstein 7-X. The study and the characterization are necessary in order to understand under which condition ECCD can be driven without posing a risk to experimental operations. The development of automatic tools is crucial to speed up the analysis of extensive datasets. In this work, we report on the first attempt of using a data-driven approach to automatically characterize the sawtooth crashes. Cluster algorithms are applied to the dataset, confirming the existence of two distinct types of crashes. This approach allows to study the two groups separately and underlines the different plasma parameters that influence the sawtooth crash parameters, for instance crash amplitude and period.
Numerical simulation of the slamming effect of regular waves and freak waves on ultra heavy-lift amphibious connector
Authors: Bao Wenqian , Pan Yuxin , Xu Gang 
Published: May 2024

Abstract
The Ultra Heavy-lift Amphibious Connector can be used for sea and land operations. When the amphibious connector opens the bow door, it will inevitably suffer from the combined action of wind, waves, currents, and other factors, resulting in the slamming of the wave on the hatch and various landing ship hull movements in the process. Due to the complexity of the actual UHAC model, in order to save computing resources, this paper selects the external load on the UAHC hatch when it is operated in water when the door is closed. The effects of crest height, draught, and focus position on UHAC slamming under the action of regular waves and freak waves were analyzed. Based on the viscous flow theory, the CFD commercial software FLUENT is used to simulate the interaction between the reduction of regular waves and floating structures. The simulation results are compared with the experimental results to verify the feasibility of the proposed method. Since the published UHAC data cannot be found in the network environment, this paper draws the UHAC based on the only data on the Internet and studies the slamming load of the wave on the UHAC on this basis.
Method for vibration and acoustic radiation analysis of underwater stiffened plates with acoustic coatings
Authors: Wang Jingyao , Li Zhe , Wang Yichuan , Hu Zhuxi 
Published: May 2024

Abstract
Based on the effective medium theory as well as the three-dimensional viscoelastic theory, a semi-analytical model of the three-dimensional underwater vibration and acoustic radiation with cavity-type stiffened plate structures covered with acoustic coatings is established to solve the issues related to underwater vibration and acoustic radiation calculation of the stiffened plate and shell structure with complex acoustic coatings. By comparing the far-field acoustic radiation characteristics of the proposed semi-analytical model and the finite element numerical model, this research verifies the validity and accuracy of the proposed model. On such a basis, this research preliminarily investigates the coupling effect exerted by stiffeners and parent plates in stiffened plates as well as the vibroacoustic characteristics of acoustic coatings, thereby providing a valuable idea for the prediction of vibroacoustic characteristics concerning underwater structures.
Comparison of impulse noise energy distribution from two generations of parachute gun
Authors: Li Jun , Xie Wujun , Li Hui , Huang Guangjun 
Published: May 2024

Abstract
The rocket ejection seat is an advanced life-saving device for fighter pilots. However, it can also produce damaging impulse noise during ejection, which could compromise the pilot’s hearing health, and the manufacturer must assess the noise damage. This study uses Variational Mode Decomposition (VMD) and Hilbert-Huang transform (HHT) to analyze energy-instantaneous distribution over time and frequency-instantaneous and energy contribution of different modes of impulse noise generated by the parachute gun in two generations of rocket ejection seats. The results demonstrate considerable disparities in the energy distribution of impulse noise generated by the parachute gun in the new generation seat compared to the old generation seat. The new generation seat has higher overall energy, more concentrated action time, and a higher energy contribution in the 1-10 kHz frequency range. These findings provide valuable data for the design of the new generation of noise protection equipment for pilots.
The calibration device research for assessing the impact exposure level of rubber balls in architectural acoustics
Authors: Li Yubin , Yan Jianwei , Yu Ling , Wang Rui , Lu An 
Published: May 2024

Abstract
In order to accurately measure the impact exposure level of rubber balls used in architectural acoustics, a calibration device is designed based on a force sensor, signal analyzer, programmable stepper motor and Infinite Impulse Response (IIR) filter. A weighing sensor with a range of 200 kg is selected to match the range of impact forces of rubber balls. The sensor is installed on a specially designed metal base plate of a rubber ball measuring fixture and connected to the signal analyzer. The rubber ball is dropped from a predetermined height in a free-fall manner to impact the sensor, generating an impact waveform. The force exposure level is then calculated by using software algorithms built into the device. The accuracy and reliability of the calibration device are evaluated by conducting repeated measurements on rubber balls and comparing the results with a known standard force exposure level curve. The experimental results demonstrate that the calibration device can consistently and stably measure the force exposure level of rubber balls, showing consistency with the known standard values. However, due to limitations such as a limited variety of measured objects and insufficient measurement repetitions, further research will be conducted to increase the number of tested rubber balls and enhance the device’s capabilities. This will provide technical support for the further development and application of the device.
Measurement method of the transient radiated noise in the reverberant pool
Authors: Yang Liuging , Zhang Jun , Wu Boyue , Wang Jiaheng 
Published: May 2024

Abstract
Transient radiated noise is the primary source of exposure for underwater targets due to its short duration and distinct spectral line characteristics. In order to accurately measure the sound source level of transient radiated noise, a reverberation method of radiated noise measurement based on power averaging processing in the frequency band is proposed. The power of the transient signal is obtained by using time-domain signal autocorrelation technology. The sound source level of the transient radiated noise in the frequency range of 500 kHz to 10 kHz is determined by the reverberant characteristics of the pool. The sound source level of the transient radiated noise in the frequency range of 1 kHz - 10 kHz is compared and measured in the anechoic tank. The deviation of the measurement results is less than 1.5 dB, which confirms the accuracy of the reverberant measurement method.
Experimental design and verification of heat transfer flow in a scaled cabin model under the influence of convective and radiative coupling
Authors: Zhong Yifei , Lan Yuqing , Luo Haining , Zhang Jiagan , Zeng Yu 
Published: May 2024

Abstract
With the development of aircraft towards high altitude, high speed, and long endurance, the influence of aerodynamic and radiant heat on the flow and heat transfer in the cabin has increased. To explore the flow conditions in the cabin under the influence of ventilation, convection, and radiation coupling, a scaled model test was conducted for verification and simulation. According to the scaling principle, a small ventilation box with a scale of 1: 5 was designed to simulate the boundary conditions in grid computing methods by building ventilation, heating, and irradiation systems. The CFD results were compared with experimental results for analysis. The results show that the experimental results of the scaled model are comparable to the flow field of the prototype model, and the experimental measurement data can be used as a reference indicator for evaluating the temperature field inside the model cabin. The comparison between the simulation experiment and the simulation results verifies the applicability of numerical calculation methods to simulate the flow field in the passenger compartment and the rationality of the scaled test technical scheme.
Numerical simulation study on noise pollution of the pressurized gas system in pumped storage power station
Authors: Long Zhe , Shu Lingfeng , Zhang Xiang , Li Chengjun , Huang Jingqian 
Published: May 2024

Abstract
To Investigate the noise pollution caused by pneumatic whistling during the blowdown operation of a pressurized gas storage system in a pumped storage power station, the flow field and sound field distribution of the gas storage tank under blowdown operation are analyzed in detail through full-channel unsteady numerical simulation of the gas storage tank and its supporting facilities. Subsequently, a comprehensive analysis of the noise issue in the gas cylinder was conducted. While investigating the mechanism of noise generation based on the distribution of noise intensity, the precise location of the noise source was pinpointed, providing a reference for the stability research of the exhaust pressurized water system.