bluuebunny/crossref_metadata_2025 huggingface dataset:
Regional Rainfall-Induced Landslide Risk Assessment Using Susceptibility Mapping and Unexpected High-Intensity Rainfall
Authors: Anees Mohd Talha , Bakar Ahmad Farid Bin Abu , Khan Mohammad Muqtada Ali
Published: October 2024

Landslides are one of the most common natural hazards in Malaysia, and besides geological conditions, rainfall intensity and duration are critical factors in assessing landslide risk. This study investigates the impact of daily rainfall variation on landslide susceptibility mapping and risk assessment. For this study, drainage, road, geological, and rainfall data were considered as key. The results show that rainfall significantly contributes to landslide risk increment by keeping geological and other triggering factors constant. Landslide vulnerability due to high-intensity rainfall was high on steep slopes causing high susceptibility compared to low-slope regions. The results also highlighted the relationship between triggering and geological factors in susceptibility assessment. Additionally, a comprehensive analysis through big data sets would help understand the spatio-temporal relationship between rainfall intensity and other landslide factors. Spatio-temporal data resolution will improve landslide susceptibility mapping and prediction accuracy to protect infrastructure and communities from potential landslide disasters in tropical climates.
Photocatalytic degradation of glyphosate using TiO2/Al2O3 using Box-Behnken Design
Authors: Nik Yusoff Nik Raihan , Mazlan Siti Norsyamiemi , Mohd Ghazi Rozidaini , Jani Musfiroh , Nik Yusoff Nik Nurul Anis
Published: October 2024

The TiO2/Al2O3 photocatalyst was produced through a hydrothermal process. The experiment was based on Box-Behnken design (BBD) considering three factors with three levels. A total of 17 experiments were designed and conducted to study the effect of variables such as TiO2/Al2O3 photocatalyst ratio (50:50 - 90:10), TiO2/Al2O3 photocatalyst amount (1.0 g – 40.0 g), and initial concentration of glyphosate (5.0 - 10.0 mg/L) on the percentage of degradation. Glyphosate degradation was conducted under UV light for three hours and monitored using a UV-Vis spectrophotometer (DR6000 HACH). Regression analysis was used to model the experimental results, and a quadratic model was established to study the effect of selected variables on the percentage of degradation. The optimal degradation percentage of 99.87% at the ratio of 50:50 TiO2 to Al2O3, the amount of 40.0 g photocatalyst TiO2/Al2O3 used, and the initial concentration of glyphosate 7.5 mg/L was obtained from the developed RSM model, and the optimized conditions were verified with experimental results. The degradation percentage was predicted using a second-order polynomial model, and the coefficient of determination (R2) were determined as 0.9133. Process variables optimized for percentage degradation were a good match for the BBD method. Finally, the prepared TiO2/Al2O3 photocatalyst was beneficial in degrading herbicides.
Spatial Distribution of Ground Level Ozone Concentrations in Klang Valley
Authors: Awang Norrimi Rosaida , Wan Azlan Wan Amar Akram , Mohd Nadzir Amni Umirah , Romazai Muhammad Sharmin , Juhan Mohamad Nasrufarisham
Published: October 2024

Ground-level ozone (O3) is a significant air pollutant formed when sunlight reacts with nitrogen oxides (NOx) and volatile organic compounds (VOCs). It poses risks to human health, vegetation, crops, and materials. This study focuses on ground-level ozone in Klang Valley, Malaysia, using hourly average data from 2010 to 2020 acquired from the Department of Environment in Klang, Shah Alam, and Petaling Jaya. Descriptive statistics and GIS tools are employed to analyse the distribution and variations of pollutants during the study periods. The study revealed that the maximum concentration in all locations in most of the year exceeded 100 ppb, with the maximum recorded in Shah Alam at 161 ppb, while mean concentrations were 13.69 – 21.18 ppb in Klang, 17.99 – 23.88 ppb in Shah Alam, and 9.40 – 17.93 ppb in Petaling Jaya, with the daily maximum concentration still exceeding the hourly average recommended value of 90 ppb. Spatial analysis using GIS reveals the distribution of O3 concentrations is highly affected by seasonal wind direction, as high O3 concentration is observed from January to March. The study underscores the pressing issue of ozone pollution in Klang Valley and the need for mitigation strategies to improve air quality.
Enhancing okra (Abelmoschus esculentus) growth performance through seed priming
Authors: Mukhtar Nur Karimah , Shamsudin Nur Naimah Mohd , Zain Norhafizah Md , Naher Laila , Abdul Rahman Kharul Azmi Mu’azzam , Sidek Noorhazira
Published: October 2024

Okra (
Abelmoschus esculentus), is a highly nutritious summer vegetable crop in Malaysia. The greatest challenge in growing okra is the okra seeds germinate slowly and unevenly, which leads to weak seedling growth and vigour. To address this issue, a study was conducted to evaluate the impact of various osmopriming techniques on Okra seed germination and performance growth. This study also aims to find effective solutions for enhancing seed germination. Different osmopriming treatments including Polyethylene glycol (PEG 20%), potassium chloride (KCl 4%), potassium dihydrogen phosphate (KH2PO4 3%), calcium chloride (CaCl2 3%), sodium chloride (NaCl 3%), potassium nitrate (KNO3 2%), and negative control (no treatment) were applied to the seeds. Data on germination rate, leaf number, plant height, chlorophyll content, and stem diameter were collected and analysed using one-way ANOVA. Among the 3 hours of osmopring treatment, KH2PO4 3% exhibited the highest germination rate (10.1886 ± 1.73894). For the 6-hour osmopriming treatment, PEG 20% demonstrated the most promising results, with the highest leaf number (3.6071 ± 0.35295), plant height (20.977±11.92103), and stem diameter (0.950±00.22281). The highest chlorophyll content was observed in the KNO3 2% osmopriming treatment (23.3286 ± 0.64104) for 6 hours. Overall, PEG 20% osmopriming treatment for 6 hours emerged as the most effective in promoting germination percentages and enhancing the growth performance of okra, serving as a positive control in the study.
Determinants of Consumer Food Waste Behaviour in Malaysia Based on the Theory of Planned Behaviour
Authors: Nazli Nur Ain Amirah , Hapiz Hana Yazmeen , Ghazali Mohd Safwan
Published: October 2024

Food waste is a critical issue affecting environmental sustainability and food security globally. This study aims to investigate the determinants of consumer food waste behaviour among households in Malaysia, adopting the Ajzen’s Theory of Planned Behaviour as the conceptual framework. A quantitative approach was adopted, with data collected from a survey of 300 Malaysian households. Descriptive statistics were used to analyse the survey data, which measured constructs such as attitudes towards food waste, subjective norms, perceived behavioural control, and food related routines. Results indicate that perceived behavioural control, shopping routines, and the reuse of leftovers are significant predictors of food waste behaviour in Malaysian households. Planning routines contribute indirectly to reducing food waste. Sociodemographic variables, including household size, income, and age, were found to have significant correlations with food waste behaviour. These findings offer valuable insights for designing targeted interventions to reduce food waste in Malaysia by enhancing household capabilities and routines related to food management. The study highlights the importance of understanding local consumer behaviour to effectively address food waste and support global sustainability efforts.
New simulation controls for the molten salt reactors related neutronic evolution code REM
Authors: Clot Louiliam , Merle Elsa , Laureau Axel , Heuer Daniel , Tillard Léa , Senentz Gérald
Published: October 2024

The in-house precision-driven material evolution code REM has been developed since the early 2000s at CNRS/LPSC Grenoble for the study and optimisation of molten salt reactors (MSR). In recent years, a particular family of these reactors has been of great interest to many players in the industry, such as the Orano group: MSRs operated as plutonium and minor actinide converters. Depletion simulation purposes has led to the development of new methods for managing supplies and the addition of new constraint parameters to the REM code. These new developments have made it possible to add new physico-chemical constraints of interest in the study of burner MSRs, such as control of the alkali or alkaline-earth fraction, or control of the volume by constraining the supply or by adding a dynamic expansion tank. These new perspectives have led to work on the numerical stabilisation of the system and the especially supplies, which has smoothed out some reactor characteristics and opened the way to interesting new research possibilities. Finally, chemical considerations on the valency of the elements and the electroneutrality of the salt raise questions about the different feeding strategies to be studied and could lead to the development of a new model for extracting materials.
The Digital Nuclear Reactor Initiative: First steps towards advanced applications
Authors: Cochet Sandrine , Caillaux Arnaud , Viot Coster Sophie , Delvaux Robin , Lenain Roland , Pipeau Yohann , Fournier Yvan , Koren Chaï , Lafaurie Clément , Calgaro Barbara , Patricot Cyril , Olita Paolo , Vaglio-Gaudard Claire , Hourez Brayan , Farda Anthime , Senechal Dorothee , Stutz Clément , Vezzoni Barbara
Published: October 2024

A large-scale research and development project, the Digital Nuclear Reactor initiative, involving the major players in the French nuclear industry has started in 2020. The project aims at developing an advanced Digital Twin comprising two innovative products: (1) a service platform for studies and (2) a new kind of simulator to respond to the growing demand of “just in time” training. After a brief overview of the Digital Nuclear Reactor initiative, the paper will focus on the service platform for advanced studies. This workbench, based on SALOME building-blocks, provides access to multi-physics and multi-scale simulations based on specialized codes couplings that can be adopted for developing new methods and expertise in support to reactor operation and design. An overview of the architectural choices implemented for allowing a modular structure of the workbench is presented. In order to illustrate the service platform functionalities, several scenarios involving different physics and scales approaches are described. Based on those scenarios, it has been possible to answer to the goal of the codes interoperability and interchangeability and their coupling with uncertainties platforms (i.e. URANIE, OpenTURNS). Specific examples are provided to illustrate the main achievements and some possible perspectives.
Dimensionality reduction through tensor factorization: Application to ab initio nuclear physics calculations
Authors: Frosini Mikael , Duguet Thomas , Tamagno Pierre , Zurek Lars
Published: October 2024

The construction of predictive models of atomic nuclei from first principles is a challenging (yet necessary) task towards the systematic generation of theoretical predictions (and associated uncertainties) to support nuclear data evaluation. The consistent description of the rich phenomenology of nuclear systems indeed requires the introduction of reductionist approaches that construct nuclei directly from interacting nucleons by solving the associated quantum many-body problem. In this context, so-called ab initio methods offer a promising route by deriving controlled (and systematically improvable) approximations both to the inter-nucleon interaction and to the solutions of the many-body problem. From a technical point of view, approximately solving the many-body Schrödinger equation in heavy open-shell systems typically requires the construction and contraction of large mode-4 (mode-6) tensors that need to be stored repeatedly. Recently, a new dimensionality reduction method based on randomized singular value decomposition has been introduced to reduce the numerical cost of many-body perturbation theory. This work applies this lightweight formalism to the study of the Germanium isotopic chain, where standard approaches would be too expansive to run. Inclusion of triaxiality is found to improve the overall agreement with experimental data on differential quantities.
Convergence of Monte Carlo methods for neutron noise
Authors: Fauvel Axel , Rouchon Amélie , Mancusi Davide , Zoia Andrea
Published: October 2024

The neutron noise δφ describes the small variations of the neutron flux around the stationary state φ0, and is typically due to vibrations or oscillations of the core components, induced by fluid-structure interactions and other generally unwanted phenomena. Knowledge of δφ is useful for core monitoring: for this purpose, in recent years several new computational methods have been proposed in order to solve the neutron noise equations with state-of-theart deterministic or Monte Carlo solvers. In this paper we present a preliminary investigation of the convergence properties of Monte Carlo methods for neutron noise analysis, in view of improving their reliability. We carry out our investigation on an infinite-medium benchmark configuration: despite the introduced simplifications, our findings suggest some universal features that represent a stepping stone towards a broader theoretical framework.
OpenMC(TD): Current status and next development stages
Authors: Romero-Barrientos Jaime , Molina Francisco , Zambra Marcelo , López-Usquiano Franco
Published: October 2024

This work presents the current state and the next stages in the development of the modified code OpenMC(TD), a modified version of the Monte Carlo code OpenMC which includes the time dependence related to the emission of β-delayed neutrons, but instead of simulating these neutrons using the traditional 6-group structure, features an implementation where individual precursors decay. This code is in active development, but already shows promising results. The upcoming development stages for OpenMC(TD) have two complimentary aspects, one related to the Monte Carlo code and another related to experimental measurements at a research nuclear reactor. Regarding the code, it is planned to implement the branchless collision variance reduction technique, while to validate the simulations, transient experiments will be performed at the RECH-1 research nuclear reactor.
Variational Quantum Simulation of Deuteron Ground State Energy at Higher Order Expansion
Authors: Liu Changyuan
Published: October 2024

Recent development of quantum computing has been extended to nuclear physics. Researchers have demonstrated that the quantum simulation of deuteron ground state energy using the variational quantum eigenvalue solver. In this existing work, only 2 and 3 qubits are used. In this work, the theory of higher order expansion of the deuteron ground state Hamiltonian has been established. On a classical quantum simulator, the convergence of the ground state energy as the number of qubits increases has been verified up to 22 qubits.
Structural damage recognition based on wavelet transform and improved most valuable player algorithm
Authors: Li Yan
Published: October 2024

The probability of damage to infrastructure increases with age. Timely health monitoring of infrastructure is essential since it is linked to the safety of people's lives and property. The study employed the wavelet transform approach to discretize the wavelet transform of the observed vibration patterns of the damaged structure in order to identify and localize the structural damage in infrastructure. The study also employed natural excitation techniques to obtain the structural multi-order modal parameters. To quantify the degree of structural damage, the study designed an objective function for damage quantification and improved the most valuable player algorithm. The study avoided the most valuable player algorithm from falling into local optimality by introducing the elite inverse strategy and simplex strategy. The wavelet transform and the improved most valuable player algorithm were able to successfully identify and localize the structural damages and quantify the degree of the damages, thereby providing technical support for the daily monitoring of the infrastructure.
Immunsuppression bei COVID-19 nach Nierentransplantation
Authors: Thorban Stefan , Matevossian Edouard
Published: October 2024

Das SARS-CoV2-Virus (SARS-CoV-2: „severe acute respiratorysyndrome coronavirus 2“) und die dadurch ausgelöste COVID-19-Erkrankung (COVID-19: „corona virus disease of 2019“) stellen ein erhebliches Risiko für Patienten nach einer Nierentransplantation dar, da in dieser Personengruppe viele Betroffene an fortgeschrittenen Organdysfunktionen und hoher Komorbidität leiden. Damit verbunden ist eine erhöhte Wahrscheinlichkeit für einen schweren Verlauf oder einen tödlichen Ausgang nach einer SARS-CoV-2-Infektion in dieser stark immunsupprimierten Patientengruppe. Neben den häufig bestehenden Komorbiditäten kann die erforderliche therapeutische Immunsuppression zu einer über 20-prozentigen Mortalität nach der Nierentransplantation führen. Die klinische Symptomatik und etablierte Risikofaktoren wie in der Allgemeinbevölkerung unterstützen diese Erkenntnisse. Es stellt sich die Frage, wie die immunsuppressive Therapie an die Behandlung von Menschen angepasst werden sollte, die nach einer Nierentransplantation an COVID-19 erkranken. Hierzu werden derzeit noch zahlreiche Studien ausgewertet, Empfehlungen für diese Erkrankungssituation sind in diesem Beitrag zusammengefasst.
Organhandel mit Nieren
Authors: López Pedro Alejandro Beltrán , Matevossian Edouard , Ehmer Ursula , Thorban Stefan
Published: October 2024

Der Organhandel ist heutzutage ein weitverbreitetes, aber selten erwähntes Problem. Einerseits gibt es in europäischen Ländern mit einem modernen Gesundheitssystem nicht die erforderliche Anzahl von Spendenden für eine Nierentransplantation, andererseits existiert ein „Transplantationstourismus“ in sogenannten „armen Ländern“. Die Wartezeit für eine Nierentransplantation kann derzeit bis zu 10 Jahre betragen und dazu führen, dass Betroffene verzweifelt nach Alternativen suchen, unabhängig von rechtlichen und moralischen Bedenken. Andererseits können Spendende in einer prekären sozialen Situation durch eine Lebendspende finanzielle Probleme vermeintlich schnell lösen. Mögliche Lösungen und Vorschläge, um die Organspendebereitschaft und damit die Zahl von verfügbaren Nierentransplantaten zu erhöhen, sind beispielsweise die Förderung von Organspenden durch mehr staatliche Programme und die Verstärkung der entsprechenden Öffentlichkeitsarbeit, oder eine Veränderung des Transplantationsgesetzes. Im Rahmen dieses Beitrags werden ein Überblick und ein besseres Verständnis für verschiedene Aspekte des Organhandels mit Nieren vermittelt. Durch Aussagen von direkt Betroffenen sowie eine ausgiebige Literaturrecherche werden die aktuellen Hintergründe des weltweiten Organhandels mit Nieren beleuchtet.
Postmortale Donation und Qualitätssicherung
Authors: Matevossian Edouard , Hüser Norbert , Naisar Sara Magdalena , Stocker Felix , Bollwein Christine , Renders Lutz , Thorban Stefan , Aßfalg Volker
Published: October 2024

Das Transplantationsgesetz (TPG) bildet die rechtliche Grundlage für die Organ- und Gewebespende. Gegenstand dieser Richtlinie sind die Anforderungen zur Qualitätssicherung in der Transplantationsmedizin. Zur Reduzierung der Risiken und zur Maximierung des Nutzens der Transplantation müssen die Eurotransplant-Mitglied-Staaten ein wirksames System für Qualität und Sicherheit anwenden. Ein Verfahren zur Qualitätssicherung in der Transplantationsmedizin soll Transparenz darüber herstellen, welche Auswirkungen einzelne Schritte im Prozess der Transplantation auf die Behandlungsergebnisse haben. Das international standardisierte Verfahren zur Qualitätssicherung bei Donation begleitet parallel den Entwicklungsprozess der Transplantationsmedizin. Die makroskopische Beurteilung des Spenderorgans durch das Explantationsteam sollte daher als obligate nützliche Ergänzung zu den bisherigen Instrumenten und etablierten Risikofaktoren angesehen und kontinuierlich weiterentwickelt werden.
Kaposiform haemangioendothelioma: ultrasonographic features and risk factors for the Kasabach–Merritt phenomenon
Authors: Zhao Jing , Yuan Jian-Jun , Dong Chang-Xian , Zhang Xiangqin , Li Chuang , Sun Qi , Wu Gang
Published: October 2024

Kaposiform hemangioendothelioma (KHE) is a rare, locally aggressive vascular tumor with high morbidity and mortality. The aim of this study was to evaluate ultrasonographic findings associated with KHE.

The clinical and ultrasonographic findings of a cohort of 64 cases with pathologically proven KHE were retrospectively reviewed and analyzed between November 2014 and February 2021. Two subtypes were divided according to the presence or absence of the Kasabach-Merritt phenomenon (KMP). The KMP risk factors in patients with KHE were analyzed statistically.

Among the 64 cases of KHE, 43 (67.2%) were accompanied by KMP. There was a positive correlation between the appearance of KMP and tumor size. KHEs had an increased risk of developing KMP if the lesions measured were >6 cm and if they belonged to the deep or mixed subtype. On ultrasonography, all KHE lesions were heterogeneous, and 81.3% were hypoechoic; 93.8% of KHEs exhibited ill-defined margins, 68.7% had strands branching into the adjacent tissue, and 84.4% presented marked hypervascularity. Elastography showed that central hypoechogenic lesion areas were hard, and surrounding hyperechogenic lesion areas were soft.

KHEs can occur in different parts of childrens’ bodies. On ultrasonography, the main findings are heterogeneous low erosions, indistinct margins, branching strangulation into adjacent tissues, and obvious hypervascularity. Patients with lesions larger than 6 cm or belonging to deep or mixed subtypes (musculoskeletal infiltrates) are at risk for developing KMP, and clinicians should be vigilant.
History Page: Leaders in MSK Radiology: Hooshang Taybi, 1919–2006
Authors: Vanhoenacker Filip M. , Lachman Ralph
Published: October 2024

This history page is dedicated to the memory and achievements of the pediatric radiologist Hooshang Taybi whose name is associated with the Rubinstein-Taybi syndrome, Taybi syndrome, and Taybi-Linder syndrome.
Metabolic Bone Diseases: Recommendations for Interventional Radiology
Authors: Di Donna Antonio , Masala Salvatore , Muto Gianluca , Marcia Stefano , Giordano Flavio , Muto Mario
Published: October 2024

Metabolic bone diseases (MBDs), including osteoporosis, osteomalacia, and Paget's disease, represent a significant challenge in medical imaging and intervention. Interventional radiologists play a pivotal role in managing these conditions, due to the crucial role of detailed and precise imaging in diagnosing and treating MBDs. This article offers comprehensive recommendations aimed at optimizing interventional radiologic practices for patients with MBDs, highlighting the importance of using advanced imaging modalities, including dual-energy X-ray absorptiometry and magnetic resonance imaging, essential for accurate assessment of bone mineral density and architecture, guiding effective intervention strategies. We also discuss the use of minimally invasive procedures like vertebroplasty and biopsy, vital for both diagnostic and therapeutic purposes, to enhance diagnostic accuracy and therapeutic outcomes, ensuring high-quality patient management in the context of MBDs.
Two Decades of High-Resolution Peripheral Quantitative Computed Tomography: Present and Future Clinical Perspectives
Authors: Boyd Steven K.
Published: October 2024

Twenty years have passed since the introduction of high-resolution peripheral quantitative computed tomography (HR-pQCT) to assess human bone microarchitecture. During that time, the technique has emerged as an important research tool used by clinicians and scientists to learn about the pathophysiology of bone adaptation in the context of osteoporosis and many other bone-affected conditions. Its rich three-dimensional data is well suited for precise longitudinal monitoring of bone microarchitecture and associated patient-specific estimated bone strength.

However, uptake of HR-pQCT as a clinical diagnostic tool has been limited, in part due to challenges such as availability, regulatory approvals, and demonstrated cost effectiveness. New research suggests fracture risk assessment using HR-pQCT is comparable with current standards based on traditional bone densitometry, but its contribution to clinical care is best suited to two areas: (1) leveraging microarchitectural information to assist in treatment decisions for the large subset of patients who lie in the so-called gray zone by current fracture risk assessment, and (2) longitudinal monitoring that establishes highly refined trajectories of bone adaptation and can inform decisions to initiate treatment, monitor treatment effects, and inform cessation.
Maglev tunnel hoods can prevent speed-driven sonic booms
Authors: Patrick Chris
Published: October 2024

Foam metal tunnel hoods could allow maglev trains to travel faster without compromising safety or comfort.
Exploring hierarchical nested riblet technology for reducing turbulent drag
Authors: Cornish Indiah
Published: October 2024

Hierarchical nested riblets can be utilized to passively decrease turbulent friction drag.
Factorized form of the dispersion relations of a traveling wave tube
Authors: Figotin Alexander
Published: October 2024

The traveling tube (TWT) design in a nutshell comprises of a pencil-like electron beam (e-beam) in vacuum interacting with guiding it slow-wave structure (SWS). In our prior studies the e-beam was represented by one-dimensional electron flow and SWS was represented by a transmission line (TL). We extend in this paper our previously constructed field theory for TWTs as well the celebrated Pierce theory by replacing there the standard TL with its generalization allowing for the low frequency cutoff. Both the standard TL and generalized transmission line (GTL) feature uniformly distributed shunt capacitance and serial inductance, but the GTL in addition to that has uniformly distributed serial capacitance. We remind the reader that the standard TL represents a waveguide operating at the so-called TEM mode with no low frequency cutoff. In contrast, the GTL represents a waveguide operating at the so-called TM mode featuring the low frequency cutoff. We develop all the details of the extended TWT field theory and using a particular choice of the TWT parameters we derive a physically appealing factorized form of the TWT dispersion relations. This form has two factors that represent exactly the dispersion functions of non-interacting GTL and the e-beam. We also find that the factorized dispersion relations comes with a number of interesting features including: (i) focus points that belong to each dispersion curve as TWT principle parameter varies; (ii) formation of “hybrid” branches of the TWT dispersion curves parts of which can be traced to non-interacting GTL and the e-beam.
Research on capacitance-coupled electrical impedance imaging fusion algorithm based on wavelet transform
Authors: Gao Heming , Pan Haoyang , Liao Zhongyu , Niu Yuguang
Published: October 2024

Capacitively Coupled Electrical Impedance Tomography (CCEIT), as a new electrical tomography method, effectively overcomes the drawbacks of traditional electrical resistance tomography that requires direct contact with liquids, so as to achieve non-contact measurement. In order to make full use of the complete electrical impedance information (real and imaginary) obtained by CCEIT and further improve the quality of image reconstruction, an image fusion algorithm based on wavelet transform was proposed. First, the Landweber algorithm is used to image the real part information and the imaginary part information, and the wavelet transform algorithm is used to decompose the two images at multiple scales, in which the low-frequency coefficient is fused by the improved logic filter algorithm based on the adaptive threshold, the high-frequency coefficient is selected based on the absolute value maximum method for fusion, and finally, the fused image is obtained by wavelet reconstruction. Numerical simulations and experiments verify the feasibility of the proposed method, and the results show that the relative error is reduced by up to 17% and the correlation coefficient is increased by up to 10%.
Modifying x-ray streak cameras for operation on igniting fusion experiments
Authors: Khan S. F. , Nyholm P. R. , Decker K. J. , MacPhee A. G. , Hilsabeck T. J. , Boyle D. , Palmer N. , Miller T. A. , Carpenter A. C.
Published: October 2024

The National Ignition Facility produced the first nuclear fusion experiment demonstrating net positive energy gain on December 5, 2022. The x-ray streak camera that measures the bang time and burn-width from this landmark experiment had an electronic failure and did not record data. The CCD sensor was replaced with a radiation hardened CMOS sensor that has since demonstrated successful operation on repeat ignition shots. Concurrently, an instrument artifact was identified that occurs when the signal consists primarily of energetic x rays >15 keV (common on burning plasma experiments). This artifact, which appears as a background pedestal, arises from the x-ray back-fluorescence generated by the solid metal accelerating mesh behind the photocathode in the streak tube. We have mitigated this background signal by limiting the sensitive area of the photocathode. Herein, the details of the modifications and the results are presented.
Epitaxial Au/Fe4N/MgO thin films on GaAs (001) substrates
Authors: Dainone Pambiang Abel , Stoffel Mathieu , Chen Tongxin , Pasquier Ludovic , Bouché Alexandre , Devaux Xavier , Vergnat Michel , Boulet Pascal , Lu Yuan
Published: October 2024

We investigate the growth of Au/FexNy/MgO trilayers on GaAs(001) substrates by plasma-assisted molecular beam epitaxy. The optimization of the growth conditions made it possible to obtain the compound of stoichiometric Fe4N. Microstructural studies show that Fe4N forms 3D islands at the initial stages of growth. As the Fe4N thickness increases, a columnar growth sets in leading to a strong texturing and to the formation of grains having the same crystallographic orientation. The growth is epitaxial with the relationship GaAs (001) [110]//MgO (001) [110]//Fe4N (001) [110]//Au (012) [0–32]. A chemical analysis at the nanoscale reveals that the interfaces are rather sharp with a limited interdiffusion. Magnetic characterizations show that a trilayer containing a 1-nm-thick Fe4N layer is already ferromagnetic. The easy magnetization axis is in-plane independent of the Fe4N layer thickness (from 1 to 6 nm). This study shows the potential to use Fe4N as a spin injector for spin-optoelectronic applications.
An efficient device model for ferroelectric thin-film transistors
Authors: Cheng Guoting , Feng Philip X.-L. , Guo Jing
Published: October 2024

Ferroelectric thin-film transistors (Fe-TFTs) have promising potential for flexible electronics, memory, and neuromorphic computing applications. Here, we report on a physics-based efficient device model for Fe-TFTs that effectively describes memory switching and device I–V characteristics. This model combines a stochastic multi-domain description of FE switching dynamics with a virtual source treatment of TFT device characteristics. It demonstrates that the memory window of Fe-TFTs depends on the amplitude and duration of the applied voltage pulses, thus suggesting quantitative means of programming and control. Additionally, we introduce a machine-learning-enabled method to automatically generate optimal voltage pulses for accurately programming multiple intermediate FE states, which is crucial for multi-bit memory and neuromorphic computing applications. To showcase the model’s applications, we simulate a 4×4 crossbar array circuit based on Fe-TFTs, highlighting its utility in performing multiply-accumulate computing operations. This small array can achieve a high speed of ∼1.28 tera operations per second (OPS) and a power efficiency of ∼0.43 W/PetaOPS. The model developed here is valuable for exploring the capabilities of Fe-TFTs in future flexible memory and computing technologies.
Insights into the growth of GaN thin films through liquid gallium sputtering: A plasma-film combined analysis
Authors: Srinivasan Lakshman , Gazeli Kristaq , Prasanna Swaminathan , Invernizzi Laurent , Roca i Cabarrocas Pere , Lombardi Guillaume , Ouaras Karim
Published: October 2024

This study presents the detailed characterization of a magnetron-based Ar–N2 plasma discharge used to sputter a liquid Ga target for the deposition of gallium nitride (GaN) thin films. By utilizing in situ diagnostic techniques including optical emission spectroscopy and microwave interferometry, we determine different temperatures (rotational and vibrational of N2 molecules, and electronic excitation of Ar atoms) and electron density, respectively. Beyond providing insights into fundamental plasma physics, our research establishes a significant correlation between gas-phase dynamics, particularly those of gallium atoms (flux and average energy at the substrate) and deposited GaN thin film properties (growth rate and crystalline fraction). These findings underscore the role of plasma conditions in enhancing thin film quality, highlighting the importance of plasma characterization in understanding and optimizing GaN thin film growth processes.
Compositionally restricted atomistic line graph neural network for improved thermoelectric transport property predictions
Authors: Wang Zeyu , Hu Run , Luo Xiaobing , Ma Jinlong
Published: October 2024

Graph neural networks (GNNs) have evolved many variants for predicting the properties of crystal materials. While most networks within this family focus on improving model structures, the significance of atomistic features has not received adequate attention. In this study, we constructed an atomistic line GNN model using compositionally restricted atomistic representations which are more elaborate set of descriptors compared to previous GNN models, and employing unit graph representations that account for all symmetries. The developed model, named as CraLiGNN, outperforms previous representative GNN models in predicting the Seebeck coefficient, electrical conductivity, and electronic thermal conductivity that are recorded in a widely used thermoelectric properties database, confirming the importance of atomistic representations. The CraLiGNN model allows optional inclusion of additional features. The supplement of bandgap significantly enhances the model performance, for example, more than 35% reduction of mean absolute error in the case of 600 K and 1019 cm−3 concentration. We applied CraLiGNN to predict the unrecorded thermoelectric transport properties of 14 half-Heusler and 52 perovskite compounds, and compared the results with first-principles calculations, showing that the model has extrapolation ability to identify the thermoelectric potential of materials.
The transformational dive of nanophotonics inverse design from deep learning to artificial general intelligence
Authors: Wang Qizhou , Zhang Yushu , Burguete-Lopez Arturo , Rodionov Sergei , Fratalocchi Andrea
Published: October 2024

The swift development of artificial intelligence (AI) is significantly transforming the paradigm of nanophotonics. Leveraging universal approximation abilities, AI models sidestep time-consuming electromagnetic simulations, opening the inverse design of photonics systems with millions of design features while offering ample stability and practical scalability compared to traditional optimization methods. This perspective discusses inverse design paradigms enabled by recent advances in AI models, discussing their roles, challenges, and opportunities envisioned by the approaching era of artificial general intelligence.
Evidence of short chains in liquid sulfur
Authors: Benmore Chris J. , Sivaraman Ganesh
Published: October 2024

High energy x-ray pair distribution function measurements show the average coordination number of the first shell in liquid sulfur is 1.86 ± 0.04 across the λ-transition, not precisely 2.0 as widely accepted. This indicates that upon melting, liquid sulfur does not comprise solely of S8 rings but also possesses a significant number of short chains. Intensities of the pre-peak and first diffraction peak of the x-ray structure factor and third peak height of the pair distribution function all show deviations at the λ-transition temperature Tλ, associated with the break-up of S8 rings and the start of oligomer polymerization. A significant number of non-bonded or loosely bonded “interstitial atoms,” with an average coordination number of 0.20 ± 0.005, are also observed in the so-called “forbidden zone” between the first and second shells upon melting. The number of interstitial atoms is found to decrease to a minimum at the λ-transition, but the majority persist into the high temperature polymerized liquid. The existence of short chains and nearby interstitial atoms represent the two main factors required to initiate the S8-ring to chain transition, as proposed by recent molecular dynamics simulations.
Low-dimensional projection of reactivity classes in chemical reaction dynamics using supervised dimensionality reduction
Authors: Tanaka Ryoichi , Mizuno Yuta , Tsutsumi Takuro , Toda Mikito , Taketsugu Tetsuya , Komatsuzaki Tamiki
Published: October 2024

Transition state theory (TST) provides a framework to estimate the rate of chemical reactions. Despite its great success with many reaction systems, the underlying assumptions such as local equilibrium and nonrecrossing do not necessarily hold in all cases. Although dynamical systems theory can provide the mathematical foundation of reaction tubes existing in phase space that enables us to predict the fate of reactions free from the assumptions of TST, numerical demonstrations for large systems have been yet one of the challenges. Here, we propose a dimensionality reduction algorithm to demonstrate structures in phase space (called reactive islands) that predict reactivity in systems with many degrees of freedom. The core of this method is the application of supervised principal component analysis, where a coordinate transformation is performed to preserve the dynamical information on reactivity (i.e., to which potential basin the system moves from a region of interest) as much as possible. The reactive island structures are expected to be reflected in the transformed, low-dimensional phase space. As an illustrative example, the algorithm is scrutinized using a modified Hénon–Heiles Hamiltonian system extended to many degrees of freedom, which has three channels leading to three different products from one stable potential basin. It is shown that our algorithm can predict the reactivity in the transformed, low-dimensional coordinate system better than a naïve coordinate system and that the reactivity distribution in the transformed low-dimensional space is considered to reflect the underlying reactive islands.
Development of a smoothed particle hydrodynamics model for porous media flows with enhanced volume conservation and the revisit of the mass conservation equation
Authors: Su Xiujia , Wang Chen , Luo Min , Zhan Yi
Published: October 2024

Porous media exist extensively in hydraulic and coastal engineering structures, while the modeling of wave/flow interaction with porous media remains challenging. This work develops a smoothed particle hydrodynamics (SPH) model for accurately simulating wave/flow interaction with porous media. The mass and momentum conservation equations incorporating the mixture theory are adopted. The resistant forces of the solid skeleton of porous media on fluid flows are described by the nonlinear empirical formula. The research contributions of the work lie in two aspects. First, two categories of mass conservation equations for porous media flow are revisited and analyzed to examine the influences of the local time derivative term of fluid volume fraction on simulation results. Second, the Volume Conservation Shifting scheme is, for the first time, introduced into SPH to enhance volume conservation for simulating porous media flows. The developed SPH model is validated by an analytical case of seepage flows in a U-tube with porous media and then applied to study four benchmark examples involving both saturated and unsaturated porous media, i.e., dam-break flow through a crushed stone dam, rapid seepage flow through a rockfill dam, solitary wave propagation over a porous seabed, and solitary wave propagation over a submerged porous breakwater. The morphological features and dynamic pressure heads of the porous media flows have been satisfactorily predicted, demonstrating the good accuracy and enhanced volume conservation of the developed SPH model.
Hydrolysis of phospholipid monolayers by phospholipase A2 revealed by heterodyne-detected sum frequency generation (HD-SFG) spectroscopy
Authors: Inoue Ken-ichi , Yamamoto Takashi , Hatori Yosuke , Hiraide Takeru , Ye Shen
Published: October 2024

Phospholipase A2 (PLA2) catalyzes the hydrolysis of the sn-2 acyl ester linkage in phospholipid, producing lysophospholipid and fatty acid in the presence of Ca2+. The hydrolysis mediated by PLA2 has attracted much interest in various fields, such as pharmacy and biotechnology. It is recognized that PLA2 cannot hydrolyze phospholipid monolayers at high surface coverage. However, the origin of different PLA2 activities is not fully understood yet. The present study investigated the interaction between DPPC (16:0 PC) monolayer and PLA2 using heterodyne-detected sum frequency generation spectroscopy, which is interface-specific spectroscopy and highly sensitive to molecular symmetry based on a second-order nonlinear optical process. It was revealed that PLA2 adsorbs to the DPPC monolayer on the aqueous solution surface only when the surface coverage is low. The adsorption at the low surface coverage significantly changes the interfacial structures of PLA2 and the hydration, which are stabilized by the presence of Ca2+. Therefore, the restriction of the hydrolysis of phospholipid monolayers at high surface coverage can be rationalized by the inhabitation of the PLA2 adsorption. The present study deepens our molecular-level understanding of the hydrolysis of phospholipids by PLA2.
Analysis of waves dynamics in a rotating detonation combustor fueled by kerosene
Authors: Fan Wenqi , Shi Yingchen , Wen Haocheng , Hu Haifeng , Chen Hongyu , Wang Bing
Published: October 2024

The wave dynamics play a crucial role in the operation characteristics of the rotating detonation engine. We conducted numerical simulations of a rotating detonation combustor (RDC) using multicomponent reactive Navier–Stokes equations coupled with a discrete phases model. The RDC in this research employs a configuration with multiple coaxial injectors supplying oxygen-enriched air and kerosene spray at room temperature. To accurately identify and analyze waves within the RDC, we proposed a three-dimensional transient detonation wave detection method based on the combined parameters of normal Mach number and heat release rate in the flow field. Two typical wave modes, referred to as single-wave mode and counter-waves mode, are identified and then selected to conduct a detailed wave dynamics analysis. The general wave behavior is discussed, and velocity deficit is compared for these two wave modes. For the single-wave mode, intermittent micro-explosions are observed generating retonation waves periodically in the unburnt pockets behind the rotating detonation shock front. For the counter-waves mode, we analyzed the collision process of the two waves and the coupling/decoupling of the shock front with the detonative heat release zone, revealing the reason for significant velocity deficits in this wave mode. This research demonstrates that micro-explosions intermittently occur in the multiphase RDC in both single-wave and counter-waves modes and generate micro explosion shock waves periodically, which influence the complicated wave dynamics behavior.
Reactive scattering of H2 on Cu(111) at 925 K: Effective Hartree potential vs sudden approximation
Authors: Smits Bauke , Sah Mantu Kumar , Naskar Koushik , Adhikari Satrajit , Meyer Jörg , Somers Mark F.
Published: October 2024

We present new quantum dynamical results for the reactive scattering of hydrogen molecules from a Cu(111) surface at a surface temperature of 925 K. Reaction, scattering, and diffraction probabilities are compared for results obtained using both an effective Hartree potential (EfHP) and a sudden approximation approach, implemented through the static corrugation model (SCM), to include surface temperature effects. Toward this goal, we show how the SRP48 DFT-functional and an embedded atom potential perform when used to calculate copper lattice constants and thermal expansion coefficients based on lattice dynamics calculations within the quasi-harmonic approximation. The so-calculated phonons are then used in the EfHP approach to replace the normal modes of a fictitious copper cluster used in earlier work. We find that both the EfHP and SCM approaches correctly predict the reaction probability curve broadening effect when the surface temperature is increased. Similarly, results for rovibrationally elastic scattering appear to be improved, predominantly for the SCM model. The behavior of the EfHP results appears to remain much closer to that of a Born–Oppenheimer static surface approach, which excludes any surface temperature effects. Finally, for the diffraction, we show very clear attenuation effects for the SCM approach, significantly decreasing specular diffraction probabilities at 925 K surface temperature. These results demonstrate that state-of-the-art theoretical models are able to reproduce strictly quantum mechanical scattering effects with a sudden approximation model and open up interesting opportunities for further comparisons to experimental diffraction results.
Dynamics of converting skyrmion bags with different topological degrees into skyrmions in synthetic antiferromagnetic nanotracks
Authors: Xu Min , Zhao Xiaoyu , Ning Jianyu , Wang Yifan , Zhang Zhiyu , Chen Wenlong , Hu Changjing , Chen Yuliang
Published: October 2024

Skyrmion bags are spin textures with any integer topological degree, which can be driven by spin-polarized currents and generate multiple skyrmions when passing through racetracks with special geometries. We have proposed three nanotrack configurations with different narrow channels on synthetic antiferromagnetic racetracks and investigated the dynamic process of current-induced conversion of skyrmion bags into skyrmions. We have found that when skyrmion bags enter narrow channels, they can be converted into magnetic domains, while when the driving force from spin-transfer torque is strong enough, the magnetic domains can break free from the pinning at the ends of channels and form skyrmions. Both the number of channels and driving current density affect the number of generated skyrmions. As the number of channels rises, magnetic domains split at the junctions of channels, forming more magnetic domains and producing more skyrmions. Furthermore, the number of generated skyrmions is also related to the quantity, arrangement, and interaction forces of inner antiskyrmions. When the number of channels remains constant, the number of antiskyrmions only affects the transition of skyrmion bags to magnetic domains and does not affect the movement of magnetic domains or the transition of magnetic domains to skyrmions. The maximum of generated skyrmions in nanotracks with triple channels reaches 9. Dzyaloshinskii–Moriya interaction and anisotropy may play an important role in the structural stability of skyrmion bags, which can affect the splitting behavior of skyrmion bags. This work is beneficial for the design of artificial synapses and the application of neuromorphic computing based on skyrmion bags.