bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment of a Large Gluteal Hydatid Cyst in Syria Using a Manual Negative Pressure Wound Therapy Device (PragmaVAC)
Authors: Netfagi M. , Alshaer H. , Abbara A. , Hariri M.
Published: September 2024

The lungs and liver are the most common sites of hydatid cysts, but they may also be found in other organs. We report the case of a lady in her 50s who presented to a hospital in northwest Syria with a large swelling in the right gluteal region. This was diagnosed as a gluteal abscess, and an incision and drainage were performed. Intraoperatively, a hydatid cyst germinal membrane was noted. She had the required imaging to exclude other cysts, which revealed a liver hydatid cyst of 7.5 cm, which was treated with PAIR (puncture, aspiration, injection, and re-aspiration) and albendazole. The residual wound was closed using a manual vacuum-assisted closure (VAC) pump for seven days. A key lesson is that a hydatid cyst in the gluteal muscles, though rare, should be considered in the differential diagnosis. We also show that the innovative use of a manual VAC pump can be used to support closure of large hydatid cyst cavities in muscles.
Practice Patterns and Incidence of Febrile Neutropenia in Patients Receiving Triplet Drug Chemotherapeutic Regimens in GUT Cancers: Do We Need to Add WBC Growth Factors? (ForGeT GCSF Study)
Authors: Venkatesh Kapu , Ramaswamy Anant , Sultana Noorzia , Bhargava Prabhat , Srinivas Sujay , Suman Mannavi , Trikha Mehak , Ostwal Vikas
Published: September 2024

Background and Objectives: There are limited data on the requirement and duration of white blood cell (WBC) growth factor (GF) administration in patients receiving biweekly docetaxel, oxaliplatin, leucovorin, 5 Fluorouracil (mFLOT) or modified FOLFIRINOX (oxaliplatin, irinotecan, leucovorin, 5 Fluorouracil (mFOLFIRINOX) regimens.

Methods: The data of 749 patients with pancreatic, gastric, and colorectal adenocarcinomas treated with mFOLFIRINOX or mFLOT for at least three cycles between January 2018 and December 2022 were retrieved.

Results: Of the 749 patients, 387 (52%) received mFLOT, while 362 (48%) received mFOLFIRINOX. Increased use of GF was seen in patients with diabetes mellitus (70 vs. 53%; p < 0.001), prior chemotherapy (82 vs. 49%; p < 0.001), prior pelvic radiotherapy (89 vs. 54%; p < 0.001), prior surgery (70 vs. 49%; p < 0.001), and stage I to III cancers as opposed to stage IV cancers (61 vs. 48%; p = 0.006). The use of GF resulted in a statistically lesser incidence of all-grades neutropenia (2.6 vs. 18.4%; p < 0.001), grade 3/4 neutropenia (1.2 vs. 12.5%; p < 0.001), and the primary endpoint of febrile neutropenia (FN; 1.2 vs. 6.1%; p = 0.001). There were no differences in the incidence of all grades of neutropenia (3.7 vs. 1.9%; p = 0.527), grade 3/4 neutropenia, and the primary endpoint of FN (1.2 vs. 1.1%; p = 0.079) in patients receiving single-day versus multiday GF, respectively.

Interpretation and Conclusion: The use of GF reduces the rates of FN by approximately 80% in patients receiving mFLOT and mFOLFIRINOX, although incidences of FN are low with these regimens. The incidence of febrile neutropenia was similar with single-dose versus multiday GF in efficacy when administered with mFLOT and mFOLFIRINOX chemotherapy.
Prevalence of Musculoskeletal Disorders among Dental Professionals: An Umbrella Review
Authors: Jain Lisha , Hegde Vivek , Shetty Rajesh , Tandale Anita , Palekar Tushar J. , Mehta Vini , S.R Srinidhi , Negi Sapna
Published: September 2024

Performing repetitive tasks on patients' mouths increases the risk of strain-related injuries for dental professionals, ultimately leading to musculoskeletal disorders (MSDs). This umbrella review aims to assess the scope of the MSD problem and identify the most often impacted body parts among dental professionals. A comprehensive search of the literature was performed from inception to March 30, 2024, in PubMed-MEDLINE, Embase, Scopus, and Web of Science databases. This review evaluated systematic reviews (SRs) and meta-analyses (MAs) of the observational studies that reported the prevalence of MSDs or any form of MSD among dental professionals such as dentists, dental hygienists, or dentistry students. The extracted data were complemented with narrative synthesis. A total of eight SRs and MAs were included in this umbrella review. Five of the eight studies were conducted globally, one in the context of Western countries and two in an Iranian context. Four of the eight studies focused on MSDs in dental practitioners, with prevalence rates ranging from 0.5 to 93%. Four body areas, that is, the neck, the lower and upper back, the shoulders and wrists, and hands were widely exposed to MSDs, with significant prevalence reported across studies. In conclusion, MSDs are common among dental professionals. Consequently, there is a pressing need to implement infrastructural and behavioral ergonomic solutions in the dental profession. However, a major concern arises from the critically low quality of available studies on MSD prevalence in dental professionals. Therefore, more rigorous research adhering to the basic quality criteria is required.
Intraoperative Incidental Internal Carotid Artery Injury in Extended Endoscopic Endonasal Approaches—Causes, Prevention, and Management: A Technical Note
Authors: Muraleedharan Manjul , Kumar Arushi , Manogaran Ravisankar , Kumar Ashuthosh , Keshri Amit Kumar , Singh Vivek , Kumar Raj
Published: September 2024

In spite of good anatomical awareness, the position of internal carotid artery (ICA) can be tricky in an intraoperative setup with disease causing very significant distortion of anatomy and shift of carotid artery and its branches. A 45-year-old gentleman presented with complaints of left hemicranial headache and painless progressive vision loss in both eyes (left more than right) for 8 months. A probable clinico-radiological diagnosis of meningioma was reached. Intraoperatively, bleeding occurred from left side ICA, control of which was achieved using a long gauze piece used as conventional nasal pack with crushed muscle beneath the gauze piece along with abdominal fat, which was further reinforced with Surgicel. The parasellar ICA is the most common segment injured. Dehiscent or bulging canal of ICA, presence of pseudoaneurysm, attachment of sphenoid septae to the canal, displacement by the lesion, nonenlarged sella because of small size of lesion or vertically oriented lesions, and vessel wall abnormalities increase the risk of injury. It is very essential to have a preoperative discussion involving the skull base surgeons (neurosurgeons and otorhinolaryngologists), neuroradiologists, and neuroanesthetists regarding the complications expected in the case. In case of ICA bleed, the target should be to achieve a temporary hemostasis. In small tears, cottonoids for pressure and bipolar for cauterization will help stop the bleeding, while in larger tears, giving moderate pressure using crushed muscle and cottonoids to achieve intra-operative hemostasis should be tried. After intraoperative hemostasis, the patient needs to be shifted to angiography suite for endovascular stent placement.
A Strike from the Air: Cerebral Hemorrhage after a Lightning Strike
Authors: Radovic Mojsije , Micovic Mirko , Zivkovic Bojana , Bascarevic Vladimir
Published: September 2024

Lightning strikes pose a rare but catastrophic risk for a variety of injuries, including damage to the central nervous system. We present the case of a 79-year-old farmer who survived a lightning strike directly in the chest resulting in an intracerebral hemorrhage in the region of the left basal ganglia. The patient was initially comatose with right-sided paralysis and central facial palsy but displayed gradual improvement with supportive medical therapy. This unique case highlights the potential for lightning strikes to cause rare and severe neurological complications, including intracerebral hemorrhage. A review of the literature proposes possible pathophysiology of lightning-induced intracerebral hemorrhage, but the exact mechanism is yet to be found. Early diagnosis, classification, and treatment of neurological symptoms are crucial for optimal patient outcomes following lightning strikes. This case report adds valuable information to the limited body of literature on lightning strike-induced central nervous system injuries, emphasizing the importance of prompt medical intervention and multidisciplinary care for lightning strike survivors. Further research is needed to better understand the mechanisms underlying lightning-induced intracerebral hemorrhage and to develop optimal treatment strategies for these rare but potentially devastating events.
Children with Sepsis Directly Admitted to a Children's Hospital Have a Lower Mortality Compared to Those Transferred from Outside Emergency Departments
Authors: Akande Manzilat , Nagpal Ashish , Muisyo Teddy , Cutler James , Anderson Michael , Allen Christine
Published: September 2024

Sepsis, severe sepsis, and septic shock are associated with high morbidity and mortality in children. We investigated the association between clinical outcomes and location of initial emergency department (ED) presentation for critically ill children with sepsis. Using the Virtual Pediatric Systems (VPS) database, we performed a 10-year retrospective cohort study of children (aged 30 days to 18 years) admitted to a VPS pediatric intensive care unit (PICU) with a primary diagnosis of sepsis, severe sepsis, or septic shock. We compared mortality, length of stay, and ventilator-free days of those who were transferred to a VPS PICU from a referring hospital ED to those who were directly admitted from the VPS PICU's hospital ED. Of the 9,833 patients, 26% were admitted from a referring ED. Overall PICU mortality was 6.3%. Transferred patients had a higher probability of death based on Pediatric Index of Mortality 3 (PIM 3) scoring (1.2 vs. 1.0; p < 0.001), longer ICU length of stay (LOS; 3vs. 2 days; p < 0.001), and were more likely to require mechanical ventilation (50 vs. 35%; p < 0.001). Direct admission from the VPS PICU's ED was independently associated with lower mortality (odds ratio [OR]: 0.81; p = 0.041) and shorter ICU LOS (21%; p = 0.009). Hospital LOS and ventilator-free days were not independently associated with the location of the initial ED presentation. In this cohort of children with sepsis, severe sepsis, and septic shock, location of initial care impacted patient outcomes. Compared to children transferred from a referring ED, children directly admitted from a VPS PICU hospital's ED had improved mortality and decreased ICU LOS.
Lesion tipo Ciclops post fractura de espinas tibiales: Reporte de caso
Authors: Figueroa David , Cifuentes Héctor , Yañez Claudio , Figueroa Francisco , Vaisman Alex , Calvo Rafael , Espinoza Jaime
Published: September 2024

La fractura de espinas tibiales es una fractura intraarticular de la inserción ósea del LCA sobre el platillo tibial, más común en niños y adolescentes entre 8 y 14 años de edad. Su incidencia se ha reportado entre 2% y 5% en la población pediátrica, pero son raras en adultos. La lesión tipo ciclops es una proliferación fibrosa de tejido de granulación, que genera un nódulo de partes blandas que limita la extensión, siendo una de las complicaciones posibles del manejo artroscópico de este tipo de fracturas. Se reporta el caso de una paciente de 25 años que cursó con fractura de espinas tibiales, donde se realizó una reducción anatómica satisfactoria de forma artroscópica y evolucionó con pérdida de extensión en el postoperatorio. Su estudio con RNM reveló una lesión tipo ciclops que requirió desbridamiento artroscópico.
Sulfur vacancy synergistically coupling grain cluster for boosting MoS2 piezoresistive properties
Authors: Pang Xing , Zhang Qi , Liang Xiaoya , Qin Weilin , Xu Hanyang , Zhao Yulong
Published: September 2024

MoS2 can be used for piezoresistive sensors because of its excellent mechanical and electrical properties. Herein, MoS2 nanoparticles with sulfur vacancies synergistically coupled with grain clusters to boost piezoresistive properties are fabricated. Moreover, we have demonstrated that they can be regulated efficiently for gauge factor (GF) from 2.97 to 9.99. In particular, the MoS2 nanoparticles with sulfur vacancies of 31.8% and grain cluster of 29.6 nm at the annealing temperature of 500 °C are compatible with synergistic optimization. The abundant sulfur vacancies provide many free electrons as carriers, benefiting the electron transport capability, and the conductive channels formed by the larger grain clusters endow structural stability and significant piezoresistive properties of the nanoparticles. This work demonstrates the promise of MoS2 nanoparticles as novel piezoresistive advanced materials.
A modified linear drag induced deceleration using a transformation of Newton’s second equation of motion
Authors: Jobunga Eric Ouma , Odhiambo Evance Ochieng , Mugambi Eric
Published: September 2024

The drag force exerted on a body moving in a fluid is empirically known to follow a linear drag law at low Reynolds numbers and a quadratic drag law at very high Reynolds numbers. The major challenge with the empirical description of the drag lies in the uncertainty of the description of the drag coefficient as a function of velocity. If the function is precisely known, it may be possible to find a general formula for the drag, which would, in principle, be applicable for all Reynolds numbers. The general law can consequently be tested using the linear and quadratic drag laws within their validity regimes to confirm its reliability and validity. The current absence of such a general law implies that the prediction of the dynamics of a body moving under drag forces in the intermediate regime of the Reynolds number can only be approximate and inaccurate since it is not guided by any valid law. In this study, we derive a general relation for the drag force, which may be applicable in all the Reynolds number regimes. We achieve this through a simple transformation of Newton’s second equation for uniformly decelerated motion. It turns out that our general relation is a modification of the linear drag law. The effect of the introduced correction term in the dynamics of a projectile is evidently promising, as can be seen in the more realistic results generated.
Fast flow field prediction based on E(2)-equivariant steerable convolutional neural networks
Authors: Jin Yuzhen , Chen Jiehao , Cui Jingyu
Published: September 2024

In the field of flow field reconstruction, traditional deep learning models predominantly rely on standard convolutions, but their predictive accuracy remains limited. To address this issue, we explore the potential of E(2)-equivariant convolutions to enhance the predictive accuracy of deep learning models for fast flow field prediction. Unlike conventional convolutions, E(2)-equivariant convolutions offer a richer representation capability by better capturing geometric and structural information. Our neural network integrates an attention mechanism that leverages the signed distance function (SDF) to encode geometric details and an indicator matrix to incorporate boundary conditions. The model predicts velocity and pressure fields as outputs. We conducted experiments specifically targeting non-uniform steady laminar flows, and the results show a 16.1% reduction in overall error compared to models based on traditional convolutions while maintaining high efficiency. These findings indicate that E(2)-equivariant convolution, coupled with an attention mechanism, significantly improves flow field prediction by focusing on critical information and better representing complex geometries.
Development of a multi-channel visible bremsstrahlung measurement system for the effective charge in the versatile experiment spherical torus (VEST)
Authors: Yoo J. W. , Sung C. , Jang J. , Eom T. H. , Lee W. S. , Kim J. H. , Byun J. H. , Jeong W. I. , Yun Hong-Sik , Jang Jae Young , Kim T. K. , Oh S. G. , Hwang Yong-Seok
Published: September 2024

A diagnostic system for measuring the effective charge in the versatile experiment spherical torus (VEST) has been developed. The system utilizes a toroidal array to observe the plasma radius on the low magnetic field side, providing a spatially resolved Zeff. The target wavelength of visible bremsstrahlung (VB) was carefully selected to avoid contamination by line emissions. The detector signal was calibrated using a halogen light source and an integrating sphere to obtain an absolute value of the radiative power from each chord. The local emissivity profile was reconstructed from the line-integrated VB emission using the Abel inversion method. Reconstruction tests were performed on various shapes of phantom profiles to effectively reconstruct the local emissivity from the measurements. We found that the initial measurements of the multi-channel VB system were consistent with the results of other independent measurements, supporting the validity of the new measurements. Finally, we obtained the initial result of Zeff in the VEST.
Experimental study on pressure and temperature distribution characteristics of subcritical and supercritical water in vertical flow channel
Authors: Jin Hui , Wang Huibo , Li Yi , Nikrityuk Petr A.
Published: September 2024

To enhance knowledge about efficiency improvement and reactor optimization in supercritical water gasification, an experimental system was designed to study the pressure and temperature distribution of subcritical and supercritical water in a channel, representing a simplified continuous reactor. The pressure drop and temperature distribution along and perpendicular to the forced flow are studied by the measure points inserted inside the test section. Experimental results show that the pressure drop in the test section is linearly negatively correlated with the average enthalpy of the inlet and outlet, eventually reaching negative values (−0.177 MPa) at high average enthalpy (2300 kJ kg−1). Temperature and specific enthalpy along the flow direction match theoretical estimates, except near the pseudocritical region. In subcritical cases, horizontal temperature differences are positively correlated with enthalpy differences and mass flow rates but remain nearly constant in supercritical cases. However, with fluid temperature rising from the pseudocritical point, the horizontal temperature difference first increases, then decreases, and reaching a peak of 4.29 K at a fluid temperature of 664 K. Analysis of the obtained data reveals that the negative correlation and values of the pressure drop are caused by fluid volume expansion. Additionally, fluid volume expansion, near-wall natural convection, and turbulent forced flow fluctuations contribute to horizontal temperature non-uniformity.
Endohedral metallofullerenes as nanoreactors: Regulating the ring-opening reaction of m-xylene at a molecular level under pressure
Authors: Zhang Ying , Liu Shuang , Yin Si , Yin Xiu , Yue Lei , Liu Ran , Liu Bo , Dong Jiajun , Lu Xing , Yao Mingguang , Shen Wangqiang , Liu Bingbing
Published: September 2024

The ring-opening reaction of aromatic molecules is a significant and critical process for the construction of carbon-based and related functional materials with desired structures and properties. However, direct observation and control of such a process at a molecular level remains a challenge. Here, we employed the octahedral voids in endohedral metallofullerene (EMF) crystals as nanoreactors to accommodate aromatic m-xylene molecules and regulate the ring-opening reaction of guest m-xylene by applying a high pressure. We found that the ring-opening reaction of m-xylenes strongly depends on the degree of charge transfer between m-xylene and EMF, which can be tuned by varying the electronegativity of the carbon cages with different endohedral metals. A positive relationship between the electronegativity of fullerenes and the reactivity of m-xylene was revealed. This work demonstrates the potential of tuning the ring-opening reaction of aromatic molecules by charge transfer and manipulates the reaction at a molecule level, providing new insights into the synthesis of carbon materials and fullerene derivatives.
Research and implementation of a large-bandwidth real-time radar jamming simulator
Authors: Wang Zhengli , Tian Shulin , Zeng Hao , Tian Yu , Wang Meng , Yu Xiaoyu
Published: September 2024

The electromagnetic environment faced by modern radar is becoming increasingly complex. One effective means to improve the performance of radar systems is testing in an anti-jamming ability test chamber, where the increased complexity has also led to higher performance requirements for radar jamming simulators. Based on the requirements for modern radar system testing, this paper presents a study of a large-bandwidth real-time radar jamming simulator and describes its overall design architecture; the simulator covers the L-Ku and Ka frequency bands and the instantaneous bandwidth is ≥2 GHz, which means that the system is able to simulate 11 interference patterns. Synchronous control of the system is realized in 1 ms through use of the reflection memory interrupt mechanism, the synchronous pulse signal mechanism, synchronous timing design, and a real-time control software architecture. An overall design scheme for real-time simulation of a radar target jamming echo is given and baseband signal processing resources are saved through information preprocessing, a large-capacity high-speed storage board is designed to improve the data reading speed, a multiphase filtering structure is used to achieve high sampling rates and save hardware resources, and a high-speed parallel computing method is used to improve computing efficiency; the actual measured baseband signal processing time is less than 500 ns. Finally, a measurement platform is built, and the main interference patterns are verified through experimental measurements.
A semi-analytical time-domain model with explicit fluid force expressions for streamwise fluidelastic instability of a single and multiple flexible tube array
Authors: Zhao Xielin , Sun Pan , Zhou Jinxiong
Published: September 2024

Fluidelastic instability (FEI) within steam generator tube arrays poses a significant safety concern for nuclear power plants. Traditionally assumed to manifest in the transverse direction, recent failures at the San Onofre Nuclear Generating Station have underscored the importance of understanding streamwise FEI (SFEI). These incidents have spurred analytical investigations into SFEI, but progress has been hindered by the lack of explicit fluid force formulations, particularly in semi-analytical SFEI models. This paper presents a novel semi-analytical time-domain SFEI model featuring an ideal geometry-based decay function and meticulously derived explicit fluid elastic force expressions. The proposed model supports both frequency-domain stability analysis and true time-domain response analysis, and it is applicable to configurations featuring either a single elastic tube in a rigid array or multiple flexible tubes in an array. Additionally, the tube motion phases are obtained by comparing time-domain responses and employing modified multi-tube frequency-domain SFEI analyses. The stability thresholds predicted for a parallel triangular array using our theoretical model closely align with reported experimental data, thereby validating its accuracy. Our work supplements and advances semi-analytical modeling, alleviating implementation challenges for analyzing SFEI phenomena.
Challenges and solutions for local flame development during spark ignition in a kerosene-fueled scramjet combustor
Authors: Bao Heng , Xiao Yunlei , Yang Daoning , Li Yang
Published: September 2024

This study experimentally investigates the challenges and solutions related to the development of local flame into global flame during kerosene spark ignition in a scramjet combustor operating at Mach 4 flight conditions. The ignition and intensity of local flame are explored with different injection pressures. Two potential solutions have been proposed to facilitate the development. The results show that injection pressure plays a critical role in controlling fuel transport into the ignition cavity T1, affecting the local equivalence ratio and local flame formation. Higher injection pressures lead to less fuel transported into cavity T1, resulting in fuel-lean local equivalence ratios and potential ignition failure. Extending the duration of ignition and injection improves ignition reliability. The suppressive effect of dense spray on local flame is the main cause of the local flame development problem. A higher injection pressure can reduce the suppressive effect and increase the intensity of downstream cavity flames. When the downstream cavity flames reach a critical intensity, the flashback of downstream cavity flame will occur, achieving global flames. The dense spray can be thinned out by very low upstream injection pressure, which can also result in global flames.
Chaotic behavior in Josephson junction for high-quality random-number generation
Authors: Oikawa D. , Komatsu H. , Tsuzuki K. , Andoh H. , Tsukamoto T.
Published: September 2024

The configuration of a high-quality security system or computer using a Monte Carlo simulation high-quality random-number generator has been expected. The high-quality random-number generators are obtained using physical randomness phenomena. In particular, chaos is an appropriate random-number generator. First, we investigate the chaotic behavior in the Josephson junction (JJ) under irradiation with external radio frequency (RF) at 77 K using an equivalent circuit of the JJ. JJ is assumed to be an intrinsic JJ in a Bi2Sr2CaCu2O8+δ single crystal. The output voltages of the JJ behave chaotic under some conditions and are evaluated using the Lyapunov exponent, Poincaré section, and attractors. Next, random numbers were generated from the chaotic output voltage in rgw JJ under irradiation with RF and evaluated by a verification test. Thus, random-number generators can be applied using the output voltage of theJJ under irradiation with external RF.
Temperature-induced hexagonal–orthorhombic phase transition in lutetium ferrite nanoparticles
Authors: Fesenko Olena M. , Fesych Igor V. , Zatovsky Igor V. , Yaremkevych Andrii D. , Rallev Maxim , Bodnaruk Andrii V. , Eliseev Eugene A. , Morozovska Anna N.
Published: September 2024

The x-ray diffraction, Raman, and infrared spectroscopies and magnetic measurements were used to explore the correlated changes of the structure, lattice dynamics, and magnetic properties of the LuFeO3 nanoparticles, which appear in dependence on their sintering temperature. We revealed a gradual substitution of the hexagonal phase by the orthorhombic phase in the nanoparticles, with sintering temperature increasing from 700 to 1100 °C. The origin and stability of the hexagonal phase in the LuFeO3 nanoparticles are of the special interest, because the nanoparticles in the phase can be a room-temperature multiferroic with a weak ferromagnetic and pronounced structural and ferroelectric long-range ordering. The antiferromagnetic and nonpolar orthorhombic phase is more stable in the bulk LuFeO3. To define the ranges of the hexagonal phase stability, we determine the bulk and interface energy densities of different phases from the comparison of the Gibbs model with experimental results. Using effective parameters of the Gibbs model, we predict the influence of size effects and temperature on the structural and polar properties of the LuFeO3 nanoparticles. Analysis of the obtained results shows that the combination of the x-ray diffraction, Raman and infrared spectroscopies, magnetic measurements, and theoretical modeling of structural and polar properties allows us to establish the interplay between the phase composition, lattice dynamics, and multiferroic properties of the LuFeO3 nanoparticles prepared under different conditions.
Divergences in classical and quantum linear response and equation of motion formulations
Authors: Kjellgren Erik Rosendahl , Reinholdt Peter , Ziems Karl Michael , Sauer Stephan P. A. , Coriani Sonia , Kongsted Jacob
Published: September 2024

Calculating molecular properties using quantum devices can be performed through the quantum linear response (qLR) or, equivalently, the quantum equation of motion (qEOM) formulations. Different parameterizations of qLR and qEOM are available, namely naïve, projected, self-consistent, and state-transfer. In the naïve and projected parameterizations, the metric is not the identity, and we show that it depends on redundant orbital rotations. This dependency may lead to divergences in the excitation energies for certain choices of the redundant orbital rotation parameters in an idealized noiseless setting. Furthermore, this leads to a significant variance when calculations include statistical noise from finite quantum sampling.
Modeling solvation dynamics of transition metal redox ion through on-the-fly multi-objective Bayesian-optimized force field
Authors: Chen Yuchi , Huang Qiangqiang , Liu Te-Huan , Yang Ronggui , Qian Xin
Published: September 2024

Modeling solvation dynamics and properties is crucial for developing electrolytes for electrochemical energy storage and conversion devices. This work reports an on-the-fly multi-objective Bayesian optimization (OTF-MOBO) method to parameterize force fields for modeling ionic solvation structures, thermodynamics, and transport properties using molecular dynamics simulations. By leveraging solvation-free energy and solvation radii as training data, we employ the data-driven OTF-MOBO algorithm to actively optimize the force field parameters. The modeling accuracy was evaluated in molecular dynamics simulations until the Pareto front in the parameter space was reached through minimized prediction errors in both solvation-free energy and solvation radii. Using transition metal redox ions (Fe3+/Fe2+, Cr3+/Cr2+, and Cu2+/Cu+) in aqueous solution as examples, we demonstrate that simple force fields combining the Lenard–Jones potential and Coulombic potential can achieve relative error below 2% in both solvation free energy and solvation radii. The optimized force fields can be further extrapolated to predict solvation entropy and diffusivities with relative error below 10% compared with experiments.
Charge self-shuttling triboelectric nanogenerator based on wind-driven pump excitation for harvesting water wave energy
Authors: Liu Shijie , Liang Xi , Han Jiajia , Duan Yuxue , Jiang Tao , Wang Zhong Lin
Published: September 2024

The most important ocean energy sources are wind energy and water wave energy, both of which are significant to carbon neutrality. Due to uneven distribution and random movement, the conversion efficiency from the two energies into electrical energy is limited, so the coupling of them is necessary. However, the current energy harvesting technologies generally target one certain type, or are simple mechanical coupling. Here, we propose a composite water wave energy harvesting scheme with wind excitation based on triboelectric nanogenerators (TENGs). A rotation TENG driven by wind is introduced as a pump to inject charges into the main TENG. For the main TENG driven by water waves, a specially designed charge self-shuttling mode is applied (CSS-TENG). Under the pump excitation, the shuttling charge amount is increased by 11.8 times, and the peak power density reaches 33.0 W m−3, with an average power density of 2.4 W m−3. Furthermore, the CSS-TENG is expanded into an array by parallel connection, and the practical applications are demonstrated. This work organically couples the wind and water wave energy in the ocean scene, through the charge pumping and self-shuttling mode, providing a new pathway for the synergistic development of clean and renewable energy sources.
Self-rectifying memristors with high rectification ratio and dynamic linearity for in-memory computing
Authors: Zhang Guobin , Wang Zijian , Fan Xuemeng , Wang Zhen , Li Pengtao , Luo Qi , Gao Dawei , Wan Qing , Zhang Yishu
Published: September 2024

In the era of big data, the necessity for in-memory computing has become increasingly pressing, rendering memristors a crucial component in next-generation computing architectures. The self-rectifying memristor (SRM), in particular, has emerged as a promising solution to mitigate the sneak path current issue in crossbar architectures. In this work, a Pt/HfO2/WO3−x/TiN SRM structure is reported with an impressive rectification ratio above 106. To elucidate the underlying mechanisms, we systematically investigate the impact of the WO3−x resistive layer thickness modulation on the device's conductive behavior. Our findings reveal that the abundant traps in the WO3−x resistive layer and the excellent insulating property of HfO2 synergistically suppress negative current while promoting positive current. According to the simulation, the crossbar array based on the proposed SRMs can realize an array scale of over 21 Gbit. Furthermore, artificial synapses fabricated using these SRMs demonstrate a remarkable linearity of 0.9973. In conclusion, our results underscore the great potential of these SRMs for the ultra-large-scale integration of neuromorphic hardware, providing a guide for future ultra-high-energy efficiency hardware with minimal circuit overhead.
A numerical method for calculating the driven current of neutral beam injection in tokamaks
Authors: Chen Wei , Cao Jinjia , Dai Yongzhi , Zhang Yulong , Zheng Xiaochang , Gong Xueyu
Published: September 2024

The current driven by neutral beam injection in tokamak is calculated, and the slowing-down distribution function of the fast ion is obtained by the backward Euler iteration method, including the pitch angle scattering collision. This study reveals that when the pitch-angle cosine is small, the trapped fast-ion current significantly contributes to the total driven current, particularly when the neutral beam is injected perpendicularly. In such cases, the current densities of passing and trapped ions are of the same order of magnitude, with the trapped fast-ion current contributing over 10% to the total neutral beam-driven current. This results in a parabolic profile of the total current in the radial direction, promoting the formation of a negative shear equilibrium structure in the core of the tokamak plasma. The numerical approach was validated against the NUBEAM code while considering electron shielding effects and applied to calculate the neutral beam-driven current in multiple tokamaks. The influence of pitch-angle cosine and neutral beam injection power on the driven current was studied at different radial positions.
Investigation of porous surface on second mode in hypersonic boundary layer
Authors: Yang Jiaji , Qiu Xinjie , Qi Zhongyang
Published: September 2024

The second mode is the main instability factor in hypersonic flow and shows the characteristics of acoustic disturbance. The stabilization effect of a porous surface on the second mode in a hypersonic boundary layer is studied according to the acoustic disturbance characteristics—including the flow characteristics of the porous surface, the effects of porous parameters, and the effect of mechanics—by direct numerical simulation. A rectangle is the basic structure of pores (slots) with a two-dimensional porous surface. The results show that the porosity (φ) and the number of pores (n) are the primary and secondary primary factors affecting the inhibition effect on the second mode by the porous surface. By influencing the amplitude and phase distribution of the pressure disturbance, the porous surface affects the wall normal transport between the mainstream and the porous surface in the near wall region, and it finally inhibits the growth of the second mode.
Computational study of heat and mass transfer with Soret/Dufour effects on power-law magneto nanofluid flow along stretching surface
Authors: Ullah Zia , Alam Md. Mahbub , Younis Jihad , Elhag S. H. , Hussain Ahmad , Haider Irfan
Published: September 2024

The theme of this study is to investigate the theoretical and numerical simulation of heat and mass transfer of magneto hydrodynamic power-law nanofluid flow over a stretching sheet with surface heat flux and Soret/Dufour effects. The mass flux and energy flux increase with temperature and concentration differences using the Soret/Dufour impact. The similarity transformations were used to transform a physical problem into a non-linear differential equation, and the non-linear equations were solved by the Keller box technique. The Soret/Dufour and magnetic field are incorporated into a nanofluid model. The similarity transformation was used to reduce thermal energy, mass, and momentum in algebraic systems. The impact of nanofluid factors, such as generalized Brownian motion parameter Nb, Dufour parameter Df, Soret parameter Sr, Le, and Pr, are generalized Lewis and Prandtl numbers; the thermophoresis parameter Nt and magnetic parameter on dimensionless stretching surface functions are shown numerically and graphically. The quantitative relationship between heat transfer and skin friction is shown by using Keller box and MATLAB. The skin friction coefficient Cf, Sherwood number Shx, and Nusselt number Nux values were also computed and displayed on the graph. The increment in slip temperature, fluid velocity, and fluid concentration is enhanced with a high Dufour parameter. The temperature variation and fluid concentration are decreased with applied-magnetic effects because the magnetic field acts like an insulating material in heat transfer systems. The enhancement in the Nusselt number and Sherwood number is increased with Soret and Dufour effects.
Dynamic deformation measurement with 2-frame phase-shifting speckle interferometry based on speckle statistics and wavefront multiplexing
Authors: Du Yijun , Li Junxiang , Fan Chen , Zhao Zixin , Zhao Hong
Published: September 2024

Phase-shifting speckle interferometry could achieve full-field deformation measurement of rough surfaces. To meet the dynamic requirement and further improve the accuracy, a two-step synchronous phase-shifting measurement system is established based on the polarization-sensitive phase modulation ability of a liquid crystal spatial light modulator; by multiplexing the reference wavefront, an accurate phase shift is generated between two independent recording channels, and a common-path self-reference vortex interference structure is built for precise spatial registration. Meanwhile, according to the speckle statistical principle, a novel two-frame phase-shifting algorithm as well as a two-step spatial registration strategy is presented to strengthen the robustness of intensity and position differences caused by spatial-multiplexing; thereby, accurate transient deformation can be directly obtained from phase-shifting speckle interferograms recorded before and after deformation. The effectiveness and accuracy of the proposal are validated from the out-of-plane deformation measurement experiment by comparing with the traditional two-step and four-step phase-shifting methods. The dynamic ability is exhibited through reconstructing mechanical and thermal deformations across various application scenarios.
Two coupled population growth models driven by Gaussian white noises
Authors: Sau Fa Kwok
Published: September 2024

Exact solution for the probability density function is considered for two coupled population growth models driven by Gaussian white noises. Moreover, n-moments of interactions of the Gompertz and Verhulst logistic models are obtained and analyzed. It is shown that interactions can modify the behaviors of the population growth models, i.e, the species may collaborate and/or compete between them.
Heavy metal fluoride glasses: A tutorial review
Authors: Poulain Marcel
Published: September 2024

Heavy metal fluoride glasses are the backbone of modern mid-infrared fiber technology. In the last few years, optical fibers made of fluorozirconate, fluoroaluminate, and fluoroindate glasses have reached the high level of reliability that is required for their widespread use in industrial and medical applications, which explains the rapid growth of this technology. In this tutorial review, the author, who was part of the team that discovered heavy metal fluoride glasses exactly fifty years ago, provides a summary of the glass synthesis process and elucidates the most important physical properties of heavy metal fluoride glasses. Finally, a brief overview of their main application areas is presented.
Compound cavity formation and splash crown suppression by water entry through proximally adjacent polystyrene beads
Authors: Watson Daren A. , Anzola Sebastian , Zeas Freddy A. , Smith Korrie B. , Cruz Anthony A.
Published: September 2024

We move forward the important topic of water entry by documenting splash dynamics arising from the impact of hydrophilic spheres with buoyant millimetric microplastics, mimicked in our study by polystyrene beads. Collision with small, buoyant beads is yet another means to manipulate splash dynamics. In this experimental study, we investigate the fluid–structure interactions between beads and hydrophilic spheres for Froude numbers in the range of 20−100. Generally, hydrophilic spheres entering a liquid bath below the critical velocity of 8 m/s produce minimal fluid displacement and no cavity formation. The presence of proximally adjacent beads atop the fluid with respect to impacting spheres promote flow separation and compound cavities for sufficiently large Froude numbers, while suppressing the growth of splash crowns. Compound cavities consist of a shallow, quasi-static first cavity that seals near the water line, and a second, deeper cavity produced in the wake of descending spheres. A vertically protruding Worthington jet follows cavity collapse. The resulting splash metrics differ from those of hydrophobic spheres with respect to the properties of impacted beads. We find impactors traversing a deep liquid pool layered with beads experience drag reduction when compared to entry into a clean pool due to the drag-reducing benefits of flow separation while not offering a high inertial penalty. Our study unravels the physics behind the widely encountered interaction of solid projectiles impacting passively floating particles, and our results translate to the entry dynamics of water-diving creatures and projectiles into water bodies polluted by floating millimetric microplastics.
The impact of mechanical strain on magnetic and structural properties of 2D materials: A Monte Carlo study
Authors: Celik Aytac
Published: September 2024

The inherent flexibility of two-dimensional (2D) materials allows for efficient manipulation of their physical properties through strain application, which is essential for the development of advanced nanoscale devices. This study aimed to understand the impact of mechanical strain on the magnetic properties of two-dimensional (2D) materials using Monte Carlo simulations. The effects of several strain states on the magnetic properties were investigated using the Lennard-Jones potential and bond length-dependent exchange interactions. The key parameters analyzed include the Lindemann coefficient, radial distribution function, and magnetization in relation to temperature and magnetic field. The results indicate that applying biaxial tensile strain generally reduces the critical temperature (Tc). In contrast, the biaxial compressive strain increased Tc within the elastic range, but decreased at higher strain levels. Both compressive and tensile strains significantly influence the ferromagnetic properties and structural ordering, as evidenced by magnetization hysteresis. Notably, pure shear strain did not induce disorder, leaving the magnetization unaffected. In addition, our findings suggest the potential of domain-formation mechanisms. This study provides comprehensive insights into the influence of mechanical strain on the magnetic behavior and structural integrity of 2D materials, offering valuable guidance for future research and advanced material design applications.
Universality and nonuniversality in nonlinear shear rheology of entangled polystyrene solutions and melts with the same number of entanglements
Authors: Liu Shuang , Wagner Manfred H. , Cui Teng , Huang Qian
Published: September 2024

The linear and nonlinear shear rheology of entangled polystyrene (PS) solutions diluted by styrene oligomers with various lengths was compared with the shear rheology of a pure melt having the same number of entanglements (Z) during startup shear and step-shear strain experiments using a cone partitioned-plate geometry. By fixing the same Z, the shear rheology of the PS solutions and the melt shows some universal features in the linear and nonlinear regimes. Undershoot of the shear stress growth coefficient is observed during the startup flow of the PS solutions and depends strongly on the length of the oligomers. The Rotation Zero Stretch model captures the stress overshoot and the steady shear viscosity quantitatively, except at the high shear rates when undershoot is observed. Stress relaxation after step-shear strain experiments reveals that the PS solutions show a transition from type A damping (close to the Doi–Edwards prediction) to type B (weaker than the Doi–Edwards prediction), while the pure melt having the same Z shows a type A response, which suggests that the length of the oligomers influences the nonlinear damping response. The nonuniversality of the nonlinear damping response of the solutions and the melt is possibly due to the changes in flow-induced friction reduction during step-shear strain deformation.
Study on the influence of high-temperature thermochemical nonequilibrium effects on the flow field characteristics around shaped wing
Authors: Chen Guang , Chen Weidong , Lu Shengzhuo , Sun Mingwu , Song Rongzheng , Sun Bo
Published: September 2024

With advances in research on hypersonic vehicles, the precise simulation of the effects of thermochemical non-equilibrium has become increasingly important in their design. In light of this, this study explores the influence of high-temperature thermochemical non-equilibrium on the characteristics of the flow field around the hypersonic wings of an aircraft. We initially conducted a numerical simulation by using the model of flow through a cylinder to validate the accuracy and reliability of an 11-species gas model in representing high-enthalpy flow fields. Subsequently, a systematic analysis was conducted on the impact of thermochemical nonequilibrium effects on the temperature, pressure, and enthalpy distribution in the flow field around a symmetric diamond wing under different Mach numbers and angles of attack. The research results indicated that the deeper reason behind the differing thermochemical nonequilibrium effects in the flow field at various Mach numbers lies in the distinct distribution of enthalpy of the air components at different locations, which provided a new perspective for understanding flow field variations from the standpoint of enthalpy. It is disclosed that the thermochemical non-equilibrium significantly altered the characteristics of the flow field, particularly at high Mach numbers and angles of attack, with a significant impact on the aerodynamic parameters of both the windward and the leeward sides of the wing. Through explaining the mechanisms of thermochemical non-equilibrium under flow fields with different structures, this study provides a theoretical foundations for and a fresh perspective on the design of hypersonic vehicles.