bluuebunny/crossref_metadata_2025 huggingface dataset:
Image plate multi-scan response to fusion protons in the range of 1–14 MeV
Authors: Vanderloo N. , Cufari M. , Russell L. , Johnson T. M. , Vargas J. , Foo B. C. , Buschmann B. I. , Dannhoff S. G. , DeVault A. , Evans T. E. , Kunimune J. H. , Lawrence Y. , Pearcy J. A. , Reichelt B. L. , Wink C. W. , Gatu Johnson M. , Petrasso R. D. , Frenje J. A. , Li C. K.
Published: September 2024

Image plates (IPs) are a quickly recoverable and reusable radiation detector often used to measure proton and x-ray fluence in laser-driven experiments. Recently, IPs have been used in a proton radiography detector stack on the OMEGA laser, a diagnostic historically implemented with CR-39, or radiochromic film. The IPs used in this and other diagnostics detect charged particles, neutrons, and x-rays indiscriminately. IPs detect radiation using a photo-stimulated luminescence (PSL) material, often phosphor, in which electrons are excited to metastable states by ionizing radiation. Protons at MeV energies deposit energy deeper into the IP compared with x rays below ∼20 keV due to the Bragg peak present for protons. This property is exploited to discriminate between radiation types. Doses of mono-energetic protons between 1.7 and 14 MeV are applied to IPs using the MIT linear electrostatic ion accelerator. This paper presents the results from consecutive scans of IPs irradiated with different proton energies. The PSL ratios between subsequent scans are shown to depend on proton energy, with higher energy protons having lower PSL ratios for each scan. This finding is separate from the known energy dependence in the absolute sensitivity of IPs. The results can be compared to complimentary work on x rays, showing a difference between protons and x rays, forging a path to discriminate between proton and x-ray fluence in mixed radiation environments.
Flow induced vibration with forced convection of a stationary and oscillating filleted bluff bodies in a staggered position
Authors: Sarout Yuvraj , Islam Md , Yap Yit Fatt , Janajreh Isam , Alam Md. Mahbub
Published: September 2024

Flow induced vibration (FIV) and forced convection heat transfer from staggered cylinders are numerically investigated with Re = 150 and Pr = 0.7. Cylinders are arranged in a staggered manner with three different stagger angles (α) = 15°, 30°, and 45°. The upstream cylinder (UC) is kept fixed while the downstream cylinder (DC) is mounted. The cross section of the bluff body is altered by parameter (r*) = 0 (square cylinder), 0.5, 0.75, and 1 (circular cylinder). For every stagger angle and r*, the reduced velocity is varied from 2 to 10. The mass ratio (m*) of the DC is kept at 10 and damping constant set to zero for maximum vibrational amplitude. The incompressible Navier–Stokes equations are coupled with Newton's equation for the mass-damper system of the vibrating cylinder. Flow induced vibration was studied with the help of frequency characteristics, dynamics response of cylinders, and instantaneous phase plots of lift and amplitude. Generally, in the case of square cylinders a delayed response can be observed as compared to other configurations. For α=15°, the DC is fully submerged into the wake of static UC. P + S (P: pair; S: singlet)-type vortices can be observed for r* = 0. For other configurations of filleted cylinders, such as r* = 0.5, 0.75, and 1 at Ur=4, 2 parallel row formation is formed due to negative sign vortices while the other one was a combination of positive and negative vortices in pseudo-P formation. At higher Ur=6 and 8, coalesced and irregular wakes can be noticed. As the stagger angle is increased to higher than 30°, the wake of both cylinders becomes more pronounced. Due to the change in stagger angle, fs (vortex shedding frequency) of UC and DC forces decouples. 2P-type vortex shedding can be observed at Ur=4 for r* = 0.75 and 1. Pairs of vortices are coupled from each cylinder in a row where negative vortices coalesce while losing energy. For lower r* = 0 and 0.5, there is a tendency for three row formation. Further increase in angle pushed the DC completely out of the wake of the UC although vortices from both cylinders are still found to interact and exhibit three row formation and 2P-type vortex shedding. Heat transfer from the DC is highly dependent on the stagger angle. For r* = 1 and 0.5 at Ur=2, the change in Nuavg is 15% and 14.7%, respectively, when the angle changed from 15° to 45°. Heat transfer from any FIV system can be directly influenced by dynamic response, position, shape, and flow topology. The generated results are provide insight for understanding the vibrational modes and heat transfer from two bluff bodies involving fluid–structure interactions.
Direct numerical simulation of skin friction drag reduction on supersonic turbulent boundary layers with micro-blowing
Authors: Zeng Fanyu , Qiu Yunlong , Jiang Zhongzheng , Tong Chuan , Hu Chenhao , Chen Weifang
Published: September 2024

The flow control mechanism and skin friction drag reduction characteristics of micro-blowing on a Ma2.25 supersonic turbulent boundary layers are investigated through direct numerical simulations, and the effects of blowing intensity and micro-hole arrangement on turbulent structure and skin friction drag in the local control region and downstream region are considered. The results show that the skin friction drag decreases remarkably in the control region under the influence of micro-blowing, and a certain drag reduction can still be maintained in the downstream region. The drag reduction performance in the control region is jointly determined by blowing intensity and micro-hole arrangement. The drag reduction performance of the staggered arrangement is 5.7% and 11.1% higher than that of the inline arrangement at blowing intensities of 0.2% and 0.5%, respectively. However, it is found that the drag reduction in the downstream region is only determined by the blowing intensity and almost independent of the micro-hole arrangement. The effect of micro-blowing on turbulent structures is quantitatively characterized by energy spectrum analysis, and it shows that the streamwise scales of the near-wall streaks are significantly reduced under the influence of micro-blowing. In addition, the compressibility of fluids and the local reverse transfer in the strong expansion region are significantly improved under the influence of micro-blowing. These effects should be considered when performing Large Eddy Simulation modeling of supersonic turbulent boundary layers with micro-blowing.
Effect of multi-temperature models on heat transfer and electron behavior in hypersonic flows
Authors: Kim Chanho , Kim Kyu Hong , Yang Yosheph , Kim Jae Gang
Published: September 2024

In hypersonic computational fluid dynamics, the two-temperature (2-T) model is widely used to simulate thermochemical nonequilibrium. The 2-T model incorporates translational-rotational and electron-electronic-vibrational energies, assuming that the integrated energies have the equivalent temperature. In this study, multi-T models are constructed to accurately predict the effects on heat flux and free electrons due to the separation of energy modes under hypersonic environments. The three-temperature (3-T) model separates the electron-electronic energy from the electron-electronic-vibrational energy of the 2-T model. The 3-T model can accurately predict the distribution and temperature of free electrons by separating the energy of free electrons, which has different characteristics from heavy particles. The four-temperature model treats rotational energy as a nonequilibrium energy mode, distinct from translational-rotational energy. While the rotational temperature reaches equilibrium rapidly at low temperatures, at high-temperature regime rotational temperature shows a relaxation time similar to that of vibrational temperature, which cannot be ignored. To develop multi-T models, electron-vibrational relaxation and translational-rotational relaxation, which are omitted in the 2-T model, are considered. Various flight test and ground facility conditions are analyzed to verify the effects of electron and heat flux under circumstances that include shock, expansion, and shock wave boundary layer interaction. The results of the multi-T models show significant differences in electron temperature and distribution caused by electron-electronic nonequilibrium. Additionally, rotational nonequilibrium increases the shock standoff distance and alters the electron distribution at high altitudes. The heat flux difference across multi-T models is found to be negligible, except in the high degree of ionization condition.
Experiments on sloshing mitigation using tuned oscillating baffles
Authors: Gligor Dan , Marques Pedro A. , Salgado Sánchez Pablo , Porter Jeff , Méndez Miguel A. , Ezquerro J. M.
Published: September 2024

We experimentally confirm the efficacy of submerged oscillating baffles for sloshing mitigation in a partially filled open container of water. As with the more typical applications of tuned mass dampers, when the natural frequency of the baffle is close to that of the first sloshing mode, the main resonance peak is split into two peaks of lower amplitude. The reduction in resonant sloshing amplitude is superior to that of a fixed baffle.
Dynamical response of a floating ice sheet due to a forced oscillation in a running stream
Authors: Hossain Selina , De Soumen
Published: September 2024

This paper explores the response of a floating ice sheet to a forced, time-harmonic oscillatory pressure applied to the ice-covered surface of a uniform, finite depth fluid. The floating ice sheet is modeled as a thin elastic plate following the Euler–Bernoulli beam equation, with the additional consideration of in-plane compressive forces acting on the ice. Employing linear wave theory, the problem is presented as an initial boundary value problem and is solved using Laplace and Fourier transforms to obtain a mathematical expression for the ice sheet's deflection in terms of infinite integrals. These integrals are thereafter solved asymptotically for large time and distance using the stationary phase method. The asymptotic analysis indicates a growing response over time when the poles and stationary points of the phase functions coalesce. The deflection of the floating ice sheet is graphically presented, highlighting the effects of various non-dimensional parameters, such as flexural rigidity, compressive force, uniform current speed, and the angular frequency of the oscillatory pressure. Additionally, the group velocity and phase velocity of flexural gravity waves are derived from the dispersion relation and elucidated using diagrams. The results show that compressive force and current speed significantly influence wave amplitude, enhancing the oscillatory nature, while the flexural rigidity of the elastic plate and the angular frequency of the applied pressure have a substantial impact on the plate's deflection.
What does it take to stabilize a naphthalene anion?
Authors: Ďurana Jozef , Kocábková Barbora , Rakovský Jozef , Pysanenko Andrij , Kresin Vitaly , Fedor Juraj , Fárník Michal
Published: September 2024

We investigate attachment of slow electrons (0–10 eV) to naphthalene (Np) clusters in a crossed beam experiment. Supersonic expansions under different conditions using different buffer gases generate the clusters: in He, Ne, and low pressure Ar, neat (Np)N clusters are formed, while we also observe mixed clusters of naphthalene with rare-gas atoms in co-expansion with Ar above 0.5 bar and with Kr. Negatively charged (Np)n− and Rgm(Np)n− (Rg = Ar, Kr) clusters are analyzed by mass spectrometry, and electron energy dependent ion yields are measured. We show that the smallest stable naphthalene complex with an excess electron, the dimer (Np)2− anion, cannot be formed in a binary collision of a free electron with (Np)2 dimer, nor with (Np)3 trimer. Evaporation of a weakly bound Ar atom(s) from a mixed ArM(Np)2 cluster following electron attachment leads to the dimer (Np)2− anion. Larger (Np)n−, n > 3, transient cluster anions decay via evaporation of an Np unit on a timescale of tens of microseconds. The self-scavenging process opens around 6 eV, where a naphthalene unit is electronically excited by the incoming electron, which is slowed down and trapped. However, the transient negative ion is efficiently stabilized only in the mixed clusters, from which Ar atom(s) can be evaporated.
Copper-rich complexes in irradiated silicon
Authors: Yarykin Nikolai , Weber Jörg
Published: September 2024

Only copper-related deep-level centers are produced by room-temperature MeV-electron irradiation in silicon doped with a high concentration of mobile interstitial copper atoms. In oxygen-lean FZ-Si, the well-known CuPL centers of four copper atoms show up in the DLTS, Laplace-DLTS, and photoluminescence measurements. In oxygen-rich Cz-Si, two new centers appear due to the irradiation at the expense of the CuPL defect. Reaction kinetics analysis correlates the new defects with oxygen, copper, and the irradiation-induced vacancy. The new defects are annealed at temperatures of 150–250 °C and, after passing through two more new configurations, are transformed into CuPL. The strong similarities to CuPL suggest that all four new defects are CuPL-like complexes of four copper atoms perturbed by a nearby oxygen.
Realising the benefits of modern fish-protection screening in Australia
Authors: Rayner Thomas S. , Boys Craig A. , Conallin John , Blackwell Boyd , Moore Anthony , Pearson Marita , Price Rodney
Published: September 2024

Context Modern fish-protection screens are being implemented globally to conserve aquatic ecosystems and protect water infrastructure. Australian governments have invested ~A$40 × 106 towards incentive programs. However, evaluation remains limited. Aims This study aimed to review progress, summarise research, and identify future priorities for screening in Australia. Methods The study analysed screen installations to date, estimating their benefits for native fish and agricultural water supply. Key results In New South Wales, 36 pumped water diversions were screened from 2018 to 2024. These installations protect over 819,000 native fish annually and can deliver up to 2600 ML of cleaner water per day, servicing over 230 km2 of irrigated agriculture. By 2026, these figures are set to rise to 48 sites, 1.72 × 106 native fish year−1 and 5461 ML day−1 of water. Conclusions Although incentive programs are generating substantial public benefits, valued at least A$177 ML−1 of water passing through a modern screen, and with benefit–cost ratios averaging 4:1, installation costs remain high and national progress has been limited. Implications Addressing these challenges is crucial to realising the full potential benefits of screening. Action is required to identify high-priority water diversions, improve affordability, encourage industry stewardship, and pursue advancements to facilitate wider adoption.
Partnering and engaging with Traditional Owners in conservation translocations
Authors: Moro Dorian , West Rebecca , Lohr Cheryl , Wongawol Ruth , Morgan Valdera
Published: September 2024

Context Conservation translocations are increasing in number and so too is the interest and expectation from Traditional Owners (TOs) that they will be involved in management occurring on their Country. Aims Our objectives were to identify the levels of past TO engagement as experienced through the western and TO lenses, examine the key steps, challenges and opportunities that emerged from survey responses, and also to provide a case study of a conservation translocation that describes Indigenous involvement to support a reintroduction of golden bandicoots (Isoodon auratus) in Australia from Martu Country (Western Australia) to Wongkumara and Maljangapa Country (New South Wales). Methods The key questions the surveys sought to address to western practitioners were as follows: (1) what types of TO involvement were observed; (2) if TOs were not involved in the translocation, was there a reason; and (3) for each translocation project where TOs were involved, (a) why was this engagement sought by their agency; (b) what worked well in terms of involvement and partnerships; and (c) how could these partnerships be improved? From a TO lens, perspectives were sought with a survey addressing the following questions: (1) how were you involved in the translocation; (2) why was it important to you and your community; and (3) ow would you like to be involved in the future? Key results Of 208 Australian translocations, 27% involved TOs. The following four themes emerged from the survey responses: the need to recognise and adopt the cultural dimension of conservation translocations on Indigenous Country, maintain on-Country relationships between western practitioners and TOs, enable co-ownership of projects, and maintain community links between western and TO practitioners. The golden bandicoot translocation partnership provided a foundation for TO engagement across generations, setting the scene for long-term and future translocation collaboration opportunities. Conclusions The perspectives of all participants involved in conservation translocations highlighted a common theme: the need to support TOs to be engaged fairly, to be culturally safe during their engagement, and to enable them to be part of a wider project and community team. The case study highlighted a sequential approach for engaging the TO organisation and supporting TOs to work alongside western practitioners to capture, record and transport animals from their Country to a new (reintroduction) site. Implications We provide suggestions for non-Indigenous managers and practitioners to consider a cultural dimension to conservation translocations when engaging TOs.
Physical extraction of antigen and information
Authors: Jiang Hongda , Wang Shenshen
Published: September 2024

To respond and adapt, cells use surface receptors to sense environmental cues. While biochemical signal processing inside the cell is studied in depth, less is known about how physical processes during cell–cell contact impact signal acquisition. New experiments found that fast-evolving immune B cells in germinal centers (GCs) apply force to acquire antigen clusters prior to internalization, suggesting adaptive benefits of physical information extraction. We present a theory of stochastic antigen transfer and show that maximizing information gain via physical extraction can explain the dramatic phenotypic transition from naive to GC B cells—attenuated receptor signaling, enhanced force usage, and decentralized contact architecture. Our model suggests that binding-lifetime measurement and physical extraction serve as complementary modes of antigen recognition, greatly extending the dynamic range of affinity discrimination when combined. This physical-information framework further predicts that the optimal size of receptor clusters decreases as affinity improves, rationalizing the use of a multifocal synaptic pattern seen in GC B cells. By linking extraction dynamics to selection fidelity via discriminatory performance, we propose that cells may physically enhance information acquisition to sustain adaptive evolution.
Structural basis for adhesin secretion by the outer-membrane usher in type 1 pili
Authors: Bitter Ryan M. , Zimmerman Maxwell I. , Summers Brock T. , Pinkner Jerome S. , Dodson Karen W. , Hultgren Scott J. , Yuan Peng
Published: September 2024

Gram-negative bacteria produce chaperone–usher pathway pili, which are extracellular protein fibers tipped with an adhesive protein that binds to a receptor with stereochemical specificity to determine host and tissue tropism. The outer-membrane usher protein, together with a periplasmic chaperone, assembles thousands of pilin subunits into a highly ordered pilus fiber. The tip adhesin in complex with its cognate chaperone activates the usher to allow extrusion across the outer membrane. The structural requirements to translocate the adhesin through the usher pore from the periplasm to the extracellular space remains incompletely understood. Here, we present a cryoelectron microscopy structure of a quaternary tip complex in the type 1 pilus system from
Escherichia coli
, which consists of the usher FimD, chaperone FimC, adhesin FimH, and the tip adapter FimF. In this structure, the usher FimD is caught in the act of secreting its cognate adhesin FimH. Comparison with previous structures depicting the adhesin either first entering or having completely exited the usher pore reveals remarkable structural plasticity of the two-domain adhesin during translocation. Moreover, a piliation assay demonstrated that the structural plasticity, enabled by a flexible linker between the two domains, is a prerequisite for adhesin translocation through the usher pore and thus pilus biogenesis. Overall, this study provides molecular details of adhesin translocation across the outer membrane and elucidates a unique conformational state adopted by the adhesin during stepwise secretion through the usher pore. This study elucidates fundamental aspects of FimH and usher dynamics critical in urinary tract infections and is leading to antibiotic-sparing therapeutics.
RIPK4 promotes oxidative stress and ferroptotic death through the downregulation of ACSM1
Authors: Zhang Jing , Wei Yuehan , Yue Yangbo , Jiao Huike , Wu Yan , Fu Wan , Lin Keng-Mean , Lu Christopher , Mou Shan , Zhong Qing
Published: September 2024

One of the most critical axes for cell fate determination is how cells respond to excessive reactive oxygen species (ROS)—oxidative stress. Extensive lipid peroxidation commits cells to death via a distinct cell death paradigm termed ferroptosis. However, the molecular mechanism regulating cellular fates to distinct ROS remains incompletely understood. Through siRNA against human receptor-interacting protein kinase (RIPK) family members, we found that RIPK4 is crucial for oxidative stress and ferroptotic death. Upon ROS induction, RIPK4 is rapidly activated, and the kinase activity of RIPK4 is indispensable to induce cell death. Specific ablation of RIPK4 in kidney proximal tubules protects mice from acute kidney injury induced by cisplatin and renal ischemia/reperfusion. RNA sequencing revealed the dramatically decreased expression of acyl-CoA synthetase medium-chain (ACSM) family members induced by cisplatin treatment which is compromised in RIPK4-deficient mice. Among these ACSM family members, suppression of ACSM1 strongly augments oxidative stress and ferroptotic cell death with induced expression of ACS long-chain family member 4, an important component for ferroptosis execution. Our lipidome analysis revealed that overexpression of ACSM1 leads to the accumulation of monounsaturated fatty acids, attenuation of polyunsaturated fatty acid (PUFAs) production, and thereby cellular resistance to ferroptosis. Hence, knockdown of ACSM1 resensitizes RIPK4 KO cells to oxidative stress and ferroptotic death. In conclusion, RIPK4 is a key player involved in oxidative stress and ferroptotic death, which is potentially important for a broad spectrum of human pathologies. The link between the RIPK4–ASCM1 axis to PUFAs and ferroptosis reveals a unique mechanism to oxidative stress–induced necrosis and ferroptosis.
Hearing triboelectricity: home experiments
Authors: Kumar Pushpendra , Dubey Shivam , Vaish Rahul
Published: September 2024

This study explores the demonstration of triboelectricity using everyday materials in a home experiment setting. By rubbing Teflon against metallic electrodes (aluminum and copper), we generated significant voltage due to Teflon’s strong electron acceptor properties. Aluminum exhibited higher voltage generation than copper, attributed to a greater electron affinity difference. To showcase practical applications, we successfully illuminated LEDs and powered a Bluetooth speaker, using the voltage generated from Teflon-metal interactions. This simple yet effective setup highlights the potential of triboelectric materials for sustainable energy harvesting and underscores the accessibility of home-based experiments in advancing scientific understanding.
Experimental analysis of hyper power impulse magnetron discharge with long pulse operation
Authors: Morel Erwan , El Farsy Abderzak , Rozier Yoann , Minea Tiberiu
Published: September 2024

Glow discharges are known to be limited for running at high current densities (typically below 0.1

A

⋅

c

m

−
2

). Magnetically enhanced plasmas overcome this limitation, reaching up to two orders of magnitude higher current densities. However, the highest reported discharge current density hardly reaches 10

A

⋅

c

m

−
2

even in high power impulse magnetron sputtering (HiPIMS). Here, we report on the long (∼1 ms) pulsed operation of the magnetron in helium with an over-dense current (∼30

A

⋅

c

m

−
2

, usual for arcs) while preserving the glow mode. This regime defying the arcs was called hyper power impulse magnetron (HyPIM) because the power injected per pulse is several times higher than in HiPIMS for the same average power and pulse duration. HyPIM operation mode is distinguished from HiPIMS by the limited pulse voltage and is unsuitable for thin film deposition but may interest plasma switches. These huge currents were obtained for two cathode materials, molybdenum (Mo) and tungsten (W). Different experimental diagnostics bring insights into the physical phenomena governing the HyPIM plasma. A discussion on the role played by the metal atoms on the current unveils the origin of such exceptional glow current all along the pulse and the key role of the helium metastable atoms. A schematic of the kinetic steps of the HyPIM discharge is proposed.
Design and experimental verification of a novel high-reliability variation of lateral doping (VLD) termination
Authors: Guo Xiao , Ren Min , Zhang Xin , Zheng Fang , Liu Siwei , Zhou Jianyu , Zheng Haowen , Ma Rongyao , Li Zehong , Zhang Bo
Published: September 2024

A novel two-dimensional mesh-like variation of lateral doping (VLD) termination (M-VLD) is proposed, which modifies the conventional ring-shaped track VLD termination (R-VLD) mask into an interconnected mesh-like structure. The comparative simulations and experiments show that M-VLD can achieve better blocking capability and reliability than R-VLD. Vertical double diffusion MOSFET (VDMOS) with M-VLD achieves a maximum breakdown voltage (

B

V

max

) of 1588 V, which is 62 V higher than that of VDMOS with R-VLD. Furthermore, the devices with M-VLD exhibit lower leakage currents in 150 °C reverse-biased

I
−
V

test and successfully pass 1000 h-125 °C-1200 V high-temperature reverse bias (HTRB) test, while the devices with R-VLD fail to pass both tests.
UV-Enhanced nonlinear optoelectronic features in iridium-doped tin oxide thin films
Authors: Hurtado-Aviles Eric Abraham , Trejo-Valdez Martín , Cabrera-Rodríguez Ohtokani , Manríquez-Ramírez María Elena , Sobral Hugo
Published: September 2024

This work explores the influence of UV light on the third-order nonlinear optical (NLO) properties of iridium-doped tin oxide (Ir-doped SnO2) films prepared by spray pyrolysis. The NLO response of these films is systematically evaluated using single-beam transmittance and two-wave mixing experiments. A nanosecond laser source emitting at 532 nm induced a two-photon absorption effect positively affected by UV irradiation, resulting in a significant improvement in the NLO properties of the Ir-doped SnO2 films. A reliable and reproducible deposition route was employed to effectively control the film thickness. The effect of Ir doping on SnO2 semiconductor thin films was meticulously characterized using various analytical methods, including scanning electron microscopy, energy dispersive spectroscopy, x-ray photoelectron spectroscopy, and x-ray diffraction analysis. Optical properties such as refractive index, extinction coefficient and thickness were investigated using ultraviolet-visible and spectroscopic ellipsometry. Additionally, the electrochemical impedance spectroscopy measurements revealed distinct optoelectronic behavior induced by an UV light source. The observed strong NLO response exhibited by the Ir-doped SnO2 thin films holds great interest for potential applications in photonic and nonlinear devices.
A novel engineered sandwich composite with ceramic-coated graphite fibre-reinforced face sheets and an auxetic core for enhanced broadband electromagnetic absorption: design using multiscale computational analysis
Authors: Phanendra Kumar A , Harursampath Dineshkumar , Ponnusami Sathiskumar A
Published: September 2024

A novel sandwich composite is designed for enhanced broadband absorption using a multiscale computational analysis. The sandwich panel is configured with BaTiO3 coated graphite fibre reinforced polymer (C-GFRP) composite, while BaTiO3 material is used as the auxetic core material. A computationally efficient in-house tool based on the variational asymptotic method is used to homogenise the electromagnetic properties and evaluate the reflection loss characteristics of the proposed sandwich structure using the scattering matrices. A detailed parametric study of 300 analyses is conducted to identify the optimal sandwich panel configurations for achieving broadband reflection loss under the normal incidence of transverse electric (TE) and transverse magnetic (TM) polarised waves. Two different configurations have been obtained, satisfying the requirements of broadband reflection loss in the X-band frequency range. Configuration (a)

V

f

= 15% without any ceramic coating, and configuration (b)

V

f

= 20% with a ceramic coating volume fraction (

C

f

) of 70%. Configuration (a) and (b) maintained the desired reflection loss of greater than −10 dB up to an incidence angle of 40° and 60°, respectively. With the demonstrated capability of covering the entire broadband frequency range, the proposed configurations can serve as baselines to explore novel ceramic-based engineered composite architectures for broadband absorption applications.
Energy harvesting from a fiber-constrained dielectric elastomer generator embedded into a novel floating wave energy harvester
Authors: Fan Peng , Han Jiachuan , Zhang Yifei , Zhang Chi , Zhu Zicai
Published: September 2024

With the increasing energy demand and growing concern about greenhouse gases emissions from fossil fuel combustion, converting the ocean wave energy into the electrical energy has emerged as a promising and sustainable solution. This paper proposes a novel floating ocean wave energy harvester based on the fiber-constrained dielectric elastomer generator (DEG) arrays and investigates the energy harvesting (EH) performance of the fiber-constrained DEG embedded into the harvester. A theoretical analysis model of the fiber-constrained DEG describing the free relaxation process is developed and verified by the existing experimental data. On this basis, the electrical energy and conversion efficiency of the fiber-constrained DEG are comprehensively analyzed under diverse system parameters, aiming to explore the feasible methods for performance improvement. Results show that both the electrical energy and conversion efficiency are enhanced by shortening the cycle period, boosting the output voltage, and increasing the time ratio of the rising segment in a cycle period. Variations of the electrical energy and conversion efficiency with the input voltage exhibit the non-monotonic behavior. In addition, at low input voltage, enlarging the maximum stretch ratio improves the EH performance, while at high input voltage, the overlarge maximum stretch ratio goes against the performance improvement. The average output power of the harvester with different lengths of rods in its displacement magnifying mechanism is also investigated. Results show increasing the rod length can improve the average output power. In addition, results can help to provide a guidance for designing a high-performance DE-based floating wave energy harvester.
Hot alkali atomic vapor in laser technology development
Authors: Lee Mingyu , Kim Seokjin , Hong Seongjin , Oh Kyunghwan
Published: September 2024

Alkali atomic vapor lasers have gained significant attention in recent decades as a promising option for high-powered and efficient laser systems. Utilizing hot alkali atomic vapor as the optical gain medium, these lasers, in principle, offer several advantages, such as high quantum efficiency, reduced thermal issues, and high beam quality. This paper reviews critical techniques developed in recent years to enhance the power and efficiency of these lasers. We discuss continuous wave laser optimization strategies, optical amplifier schemes, and pulsed laser generation based on hot alkali atomic vapor cells. Additionally, select findings from the authors’ research group are presented.
Analyzing the inverted fractional rössler system through two approaches: numerical scheme and LHAM
Authors: Abdoon Mohamed A , Elbadri Mohamed , Alzahrani Abdulrahman B M , Berir Mohammed , Ahmed Abubker
Published: September 2024

This paper aims to develop the scenario to find out how two approaches can be employed in estimating the numerical results in systems. The first technique is the application of the Caputo Fabrizio fractional schema, which is a method for overcoming the challenges of singular calculus while providing a generalized approach in a more flexible framework. The second approach involves the Laplace transform and the Homotopy analysis method (LHAM) to give an analytical solution that inherits good features of both methods, capable of tackling nonlinearity and yielding fast convergence. In the present work, we use these techniques to investigate the inverted Rössler system where the equations are defined within the Caputo Fabrizio derivative. By applying this system, which is associated with behaviour analysis using both methods, we conclude that Caputo Fabrizio is more appropriate for deriving solutions, whereas LHAM is preferable since it converges rapidly and is computationally efficient. Comparisons are provided for the validity of the outlined approaches, which is corroborated by the potential use of such methods in solving systems that recognize ‘chaotic’ patterns and in extending the applications of the forecasting approaches identified to other branches of science and engineering. Besides, an additional analysis focuses on the strengths and weaknesses of each method to enable the user to understand how the method works and how it produces results.
A comparison of the acoustic waves generated in proton and carbon ion therapy
Authors: Halıcılar Fulya , Arık Metin , Erkol Hakan
Published: September 2024

Hadron therapy, which employs particles such as protons and carbon-ions, is a promising method of cancer treatment due to its unique ability to deliver maximum energy at the Bragg peak near the tumor, sparing surrounding healthy tissue. Ionoacoustic waves, generated by thermal expansion from electronic collisions and localized heating, can be detected to optimize dose delivery and verify particle range, thus improving treatment precision. These waves offer a unique opportunity for comparative studies of different particle therapies. In this study, a mathematical model and computational simulations are used to compare the characteristics of ionoacoustic waves generated in tissue by proton and carbon-ion beams. In particular, we assess the impact of the nuclear fragmentation tail on the ionoacoustic signals generated in carbon-ion therapy. Our approach will allow us to make some important observations to study the comparative effects of proton and carbon-ion therapy. The aim of this work is to perform a comprehensive comparative analysis of ionoacoustic waves from proton and carbon-ion treatments, focusing on their potential for in-vivo range verification. This research addresses the current gap in understanding the use of ionoacoustic signals for range verification in ion beam therapy, which is critical given the growing clinical application of carbon ion therapy and its under-explored acoustic properties. This study pioneers the feasibility of using acoustic imaging from carbon-ion beams to detect the Bragg peak position and measure tumor dose in real-time. Carbon-ion dose mapping and relative biological effectiveness (RBE) assessment can be facilitated by real-time signal monitoring. Our study aims to significantly advance the field by addressing the lack of a verification technique for carbon-ion beams, focusing on the considerable impact of the nuclear fragmentation tail on ionoacoustic signal waveforms, which provides crucial insights into the unique energy deposition properties of carbon-ions.
The impact of quantum correlations on parameter estimation in a spin reservoir
Authors: Mirza Ali Raza , Al-Khalili Jim
Published: September 2024

We study the impact of quantum correlations existing within the system-environment thermal equilibrium state while estimating the parameters of the spin reservoir. By employing various physical situations of interest, we present results for the reservoir temperature and its coupling strength with the central two-level system. The central system (probe) interacts with the bunch of randomly oriented spin systems and attains a thermal equilibrium state. We consider a projective measurement which prepares the probe’s initial state, and then the global system (probe and reservoir) evolves unitarily. The reduced density operator encapsulates the information about the spin reservoir which can be extracted by doing measurements on the probe. The precision of such measurement is quantified by quantum Fisher information. We repeat this process if the probe-reservoir initial state is not correlated (product state). We compare the estimation results for both with and without the outturn of initial correlations. In the temperature estimation case, our results are promising as one can significantly improve the accuracy of the estimates by including the effect of initial correlations. A similar trend prevails in the case of coupling strength estimation especially at low temperatures.
Parallel Analogy Method for Measuring FRD of the FASOT-IFU
Authors: Chen Xudong , Yan Yunxiang , Yan Qi , Wang Anzhi , Sun Kangquan , Peng Zifu , Wang Jiabin , Wang Pengfei , Zhong Yue , Qu Zhongquan , Geng Tao , Sun Weimin
Published: September 2024

A fiber integral field unit (IFU) was chosen for the Fiber Array Solar Optical Telescope (FASOT) to obtain high-spectral-resolution polarization solar spectral images. This IFU features a dual-array-end design, complemented by a dozen slit ends. Each consists of 2 sub-slits corresponding to the dual array ends. In order to accurately and quickly measure the focal ratio degradation of 8064 fibers in FASOT-IFU, a parallel analogy method (PAM) for FASOT-IFU was proposed. This method primarily relies on characterizing the focal ratio based on the full-width at half-maximum (FWHM) of the fiber’s output spot, and the linear relationship between the output focal ratio of the spot and the FWHM. By precisely calculating the focal ratio of the positioning fiber in the FASOT-IFU and treating it as a reference, the output focal ratio of the working fiber can be obtained by comparing the FWHM of the working fiber spot and the positioning fiber spot at the same emission distance. The average value of the output focal ratio by PAM corresponding to the 4032 fibers from Array A of the IFU is 6.0 and the standard deviation is 0.6. The values corresponding to the Array B are 6.2 and 0.40, respectively. The mean value exceeds the contractually specified F/5.5, and the proportion of optical fibers with a focal ratio greater than 5.5 accounts for 88% of the total number of optical fibers, meeting the design requirements of the FASOT system.
Analysis and measurement of vibration characteristics of a hollowing defect based on a laser self-mixing interferometer
Authors: Chen 陈 Yu-Xin 煜昕 , Chen 陈 Jin-Bo 金波 , Cao 曹 Peng 鹏 , Zhao 赵 You-Guang 有光 , Wang 王 Jun 钧 , Teng 滕 Xu-Wei 旭玮 , Wang 王 Chi 驰
Published: September 2024

To solve the problems with the existing methods for detecting hollowing defects, such as inconvenient operation, low efficiency and intense subjectivity, and to improve the efficiency of the acoustic-optic fusion method for detecting hollowing defects, in this paper the vibration characteristics of hollowing defects are measured and analyzed using a laser self-mixing interferometer. The ceramic tile above the hollowing defect is equivalent to a thin circular plate with peripheral fixed support. According to Kirchhoff’s classical circular plate theory and the circular plate displacement function based on the improved Fourier series, a theoretical model of a circular plate is established. By solving the characteristic equation, the theoretical modal parameters of hollowing defects are obtained. Subsequently, an experimental system based on a laser self-mixing interferometer is built, and modal experiments are carried out using the hammering method. The experimental modal parameters are obtained with a professional modal analysis software. Through comparative analysis between the theoretical and experimental modal parameters, the error of the natural frequency results is found to be tiny and the mode shapes are consistent. These results provide theoretical guidance for a practical non-destructive acoustic-optic fusion method for detecting hollowing defects.
Micron-resolved quantum precision measurement of magnetic field at the Tesla level
Authors: An 安 Si-Han 思瀚 , Ge 葛 Shi-Yu 仕宇 , Lu 卢 Wen-Tao 文韬 , Chen 陈 Guo-Bin 国彬 , Xia 夏 Sheng-Kai 圣开 , Chen 陈 Ai-Qing 爱庆 , Wang 王 Cheng-Kun 成坤 , Yu 虞 Lin-Yan 林嫣 , Zhang 张 Zhi-Qiang 致强 , Wang 汪 Yang 洋 , Tang 唐 Gui-Jin 贵进 , Cheng 程 Hua-Fu 华富 , Du 杜 Guan-Xiang 关祥
Published: September 2024

We develop a quantum precision measurement method for magnetic field at the Tesla level by utilizing a fiber diamond magnetometer. Central to our system is a micron-sized fiber diamond probe positioned on the surface of a coplanar waveguide made of nonmagnetic materials. Calibrated with a nuclear magnetic resonance magnetometer, this probe demonstrates a broad magnetic field range from 10 mT to 1.5 T with a nonlinear error better than 0.0028% under a standard magnetic field generator and stability better than 0.0012% at a 1.5 T magnetic field. Finally, we demonstrate quantitative mapping of the vector magnetic field on the surface of a permanent magnet using the diamond magnetometer.
Calibration of an ionisation chamber for parent–progeny decay
Authors: Pommé S
Published: September 2024

For a single radionuclide being measured in an ionisation chamber, a calibration factor can be established that relates the ionisation current to the source activity. The same applies to a decay chain in secular equilibrium, for which the calibration factor comprises the ionisation current produced by the parent and progeny nuclei combined. The calibration of an ionisation chamber for non-equilibrated parent–progeny decay poses a problem because the activity ratio of the parent and progeny nuclei varies with time. This study examines cases in which the half-lives of the parent and only one of the progenies in the decay series are significantly long. Thus, two calibration factors are involved, which combine differently as a function of time. By means of nuclear dating of the material, the parent–progeny activity ratio can be determined, and the respective contributions to the ionisation current can be unambiguously distinguished. Once the ionisation chamber is calibrated, two measurements taken at different times are sufficient to determine the activity and age of the parent–progeny mixture. This study presents equations for calculating the calibration factors and propagating uncertainties, illustrated with a case study focusing on the 227Th/223Ra decay chain used in alpha-immunotherapy.
Error field predictability and consequences for ITER
Authors: Pharr M. , Logan N.C. , Paz-Soldan C. , Park J.K. , Hansen C.
Published: September 2024

ITER coil tolerances are re-evaluated using the modern understanding of coupling to least-stable plasma modes and an updated center-line-traced model of ITER’s coil windings. This reassessment finds the tolerances to be conservative through a statistical, linear study of n = 1 error fields (EFs) due to tilted, shifted misplacements and nominal windings of central solenoid and poloidal field coils within tolerance. We also show that a model-based correction scheme remains effective even when metrology quality is sub-optimal, and compare this to projected empirical correction schemes. We begin with an analysis of the necessity of error field correction (EFC) for daily operation in ITER using scalign laws for the EF penetration threshold. We then consider the predictability of EF dominant mode overlap across early planned ITER scenarios and, as measuring EFs in high power scenarios can pose risks to the device, the potential for extrapolation to the ITER Baseline Scenario (IBS). We find that carefully designing a scenario matching currents proportionally to those of the IBS is far more important than plasma shape or profiles in accurately measuring an optimal correction current set.
Uncertainty analysis of a non-contact image-based measurement system for tracking mandibular movements path
Authors: Truffarelli Tiberio , Valenti Chiara , Tribbiani Giulio , Pagano Stefano , Marsili Roberto , Rossi Gianluca
Published: September 2024

Tracking mandibular movements is essential for the production of personalized gnathologic and prosthetic devices. The market offers several solutions of optical systems aimed at tracking the jaw, instruments that, using a camera and specific markers, allow reconstructing free mandibular movements. The purpose of this study is to analyse the measurement uncertainty of one of these new systems through comparison with a reference technique on simple linear displacements.
Application of the tomographic BOS technique to a H2-air premixed flame
Authors: Iapaolo F. , Cozzi F. , Orlando M.
Published: September 2024

Background Oriented Schlieren (BOS) is a line of sight optical (LoS) technique used for visualizing and measuring density gradients in transparent media by exploiting the fluid density and refractive index relationship. This study applies BOS to a premixed axis-symmetric hydrogen flame, aiming to quantitatively estimate its density and temperature distributions using the ARAP (Arbitrary Ray Axisymmetric Projection) deconvolution algorithm. The BOS technique consists in acquiring images of a background with and without the flame; light rays passing through the flame are deflected due to the heterogeneous refractive index field. Cross-correlation algorithms are then employed to quantify these deflections. The ARAP transform is preferred to Abel-based methods because it models light rays as converging to a single point according to the pinhole camera model. Assuming constant composition, density gradients are evaluated, and considering ideal gas behaviour and constant pressure, the temperature distribution is estimated. The study explores the influence of parameters like regularization and integration steps for the ARAP transform. Consistency analysis involves evaluating temperature trends at various flame heights and comparing them with thermocouple measurements. Additionally, a preliminary estimation of tomographic BOS uncertainties is provided.
The Effect of Noisy Magnetic Fields on Electrons
Authors: David Castaño-Yepes Jorge , Loewe Marcelo , Muñoz Enrique , Cristóbal Rojas Juan , Zamora Renato
Published: September 2024

In this work, we study the behavior of an electron in the presence of a constant and uniform magnetic field, which is subjected to white noise fluctuations with an autocorrelation of magnitude Δ
B
. Starting from the Schwinger representation for a propagator in the presence of a constant magnetic field, we use the method of replicas to determine the effect of the magnetic noise on the shape of the renormalized quasi-particle parameters. Leading to an effective charge and an effective refraction index that depend not only on the energy scale, as usual, but also on the magnitude of the noise ΔB and the average field B.