bluuebunny/crossref_metadata_2025 huggingface dataset:
Simpaticectomía Periarterial Periférica Extendida en Isquemia Digital Crónica
Authors: Caloia Martín Fernando , Ronconi Sergio Emanuel , Muñoz Mariana , Fernandez Sofía , Caloia Hugo Fernando
Published: December 2024

Introducción En aquellos pacientes con isquemia crónica digital que no responden al tratamiento médico, la simpaticectomía cervical endoscópica tiene su lugar, pero puede asociarse con hiperhidrosis compensatoria posoperatoria. La simpaticectomía periférica o digital resulta menos exigente técnicamente y con menos complicaciones que la central o cervical.

Objetivo evaluar los efectos de la simpaticectomía Peri-Arterial periférica extendida en pacientes con isquemia distal crónica, refractaria al tratamiento médico; y comparar estos resultados con los diferentes reportes de la literatura.

Materiales y Métodos Estudio retrospectivo, descriptivo y analítico, de una serie de 14 pacientes tratados entre los años 2005 y 2021; a los que se le realizó simpaticectomía peri arterial periférica extendida.

Resultados 11 mujeres y 3 varones con una edad promedio de 48 años (28-63). En 11 de los 14 casos se observó una mejoría y/o disminución en el número de lesiones ulceradas, y en todos los casos se constató una disminución franca del dolor, desde el primer día post operatorio.

Conclusiones La simpaticectomía peri arterial periférica extendida mejora y/o detiene las lesiones de la isquemia digital crónica.
Bulto dorsoradial de la muñeca: Desaparición de la tabaquera anatómica como un signo de “SLAC”
Authors: de Oliveira Ricardo Kaempf , Colombelli Luna Hussein , Kakar Sanjeev , Atzei Andrea , Baixauli Vicente Carratalá , Delgado Pedro J.
Published: December 2024

La tabaquera anatómica, una región triangular en la porción dorso-radial de la muñeca, es un punto de referencia anatómico clave. Está delimitada por los tendones del extensor largo del pulgar, extensor corto del pulgar y abductor largo del pulgar, y alberga la arteria radial y ramas nerviosas. Patologías como quistes sinoviales, fracturas y osteofitos pueden alterar su apariencia. Estudios sobre lesiones del ligamento escafolunar (SLL) muestran que el daño crónico provoca el desplazamiento dorso-radial del escafoides, iniciando un proceso degenerativo conocido como colapso avanzado escafolunar (SLAC). Esto a menudo resulta en la "desaparición" de la tabaquera anatómica, lo que facilita la identificación de pacientes con muñeca SLAC junto con síntomas como dolor y rigidez. La afección es impulsada por la formación de osteofitos, subluxación del escafoides y sinovitis, lo que conduce a inestabilidad articular y deformidad. Los tratamientos tradicionales, como la estiloidectomía, pueden no resolver completamente la inestabilidad. Nuevos enfoques que consideran la dinámica tridimensional de la muñeca podrían ser más efectivos para manejar el SLAC. Estudios biomecánicos sugieren que las lesiones del SLL, junto con la pérdida de estabilizadores secundarios, provocan que el escafoides se pronuncie y flexione, resultando en una proyección dorso-radial dentro de la fosa del escafoides. Sin tratamiento, esto puede progresar a SLAC, frecuentemente caracterizado por el "bulto dorso-radial de la muñeca".
Síndrome de Lacertus Fibroso: “Los ojos solo ven lo que la mente conoce”
Authors: Azócar Camila , Román Javier , Hagert Elisabet
Published: December 2024

El síndrome del lacertus fibroso (LF) es la causa más frecuente de compresión proximal del nervio mediano alrededor del codo. Se caracteriza por dolor en el antebrazo y debilidad en ciertos movimientos de la mano y muñeca.

Es una patología habitualmente subdiagnosticada, que requiere de una alta sospecha clínica y una minuciosa exploración en el examen físico, dado que los exámenes complementarios de imágenes y electrodiagnóstico suelen no ser de utilidad.

Inicialmente, es de tratamiento conservador, pero frente a la falla de este, la liberación quirúrgica puede estar indicada.

La técnica de liberación del LF puede realizarse bajo una técnica de anestesia local sin sedación ni torniquete de isquemia (WALANT) lo que permite al cirujano evaluar en el intraoperatorio la recuperación inmediata de la fuerza de los grupos musculares comprometidos en esta condición. Los resultados funcionales postoperatorios han demostrado ser excelentes en cuanto a la resolución del dolor y la recuperación de la fuerza

El síndrome de LF es frecuente, debe ser diagnosticado y tratado de manera correcta para lograr una resolución satisfactoria de la sintomatología.
Planificación 3D y corrección de deformidades del antebrazo en adolescentes con exostosis múltiple: Resultados clínicos
Authors: Aita Marcio Aurelio , Rodrigues Fabio Lucas , Carvalho Victor Bignatto , Moretto Renato Tadeu Sassmannshausen , Barbosa Kleber Oliveira , de Oliveira Ricardo Kaempf
Published: December 2024

A pesar de que entre el 30% y el 60% de los pacientes con exostosis cartilaginosa múltiple (ECM) presentan deformidad en el antebrazo, todavía no existe un consenso sobre el método preferido ni el momento ideal para el tratamiento, especialmente en pacientes adolescentes con múltiples lesiones, en quienes el momento del tratamiento puede tener un fuerte impacto psicológico, ya que el trastorno en el crecimiento óseo endocondral puede llevar a la inestabilidad articular y a deformidades graves de la extremidad afectada. El alargamiento del cúbito, la osteotomía del radio, la estabilización de la articulación radiocubital distal (ARCD) y la reducción de la cabeza radial pueden ser una buena estrategia para corregir la deformidad del miembro superior. Este estudio tuvo como objetivo mostrar una planificación y un procedimiento reproducibles para corregir la deformidad del radio, la subluxación de la articulación radiocapitelar, el cúbito minus, el equilibrio carpiano y la incongruencia de la ARCD en adolescentes tratados con el protocolo ABC (fijación externa híbrida y placa volar de radio utilizando un modelo 3D y métodos de planificación por software) en cinco adolescentes con ECM y deformidad en el antebrazo. Después de un año de la cirugía, los pacientes mostraron una puntuación DASH de 8 y una puntuación EVA de 1. En el examen radiográfico, el ángulo articular radial (AAR) fue de 21,55°, la inclinación palmar de 10°, la variación cubital (VC) de 1,2 mm, el deslizamiento carpiano (DC) de 64%, el centro de rotación de la angulación (CORA) de 1,1° hacia el cúbito / 21,95° hacia el radio, y el arqueamiento radial (AR) de 11,45 mm. La tasa de complicaciones fue del 20% (un paciente) que fue sometido a un re-alargamiento del cúbito para mejorar la congruencia de la ARCD. Se encontró que el protocolo ABC (fijación externa híbrida y placa volar de radio utilizando un modelo 3D y un sistema de planificación por software) es un método de tratamiento seguro y confiable para la deformidad del antebrazo en adolescentes con ECM.
Privileged interests on the party agenda: Bitcoin-related issues in two countries since 2020
Authors: van Spanje Joost , Ciobanu Costin , Sanna Greta Arancia
Published: December 2024

What explains whether and how much political parties give attention to a policy issue? Parties are expected to cater to the interests of privileged groups and to be dismissive unless an issue offers an electoral opportunity. How to test this? Most issues have been around for so long that it has become difficult to track party responses. Ideally, a multifaceted phenomenon would fall from the sky and become favored by privileged groups, after which we would observe party reactions. Bitcoin fulfills these criteria. It has become significant, suited for various ideologies yet disproportionally supported by wealthy, highly educated male voters. In this paper, we study how new issues emerge around Bitcoin, and how parties respond. Voter attitudes, preferences, expectations, and Bitcoin ownership are taken from our 2020-2023 four-wave British (N=5,121) and Dutch (N=5,002) voter surveys. Party positions on Bitcoin are derived from our surveys of MPs and party representatives, cross-validated by party communication. Using issue yield theory, we find that weak electoral incentives, particularly due to age-related internal divisions, prevent parties from catering to privileged groups on Bitcoin issues. This suggests that a party system will not embrace elite interests, even on low-salience issues, under unfavorable public opinion alignments.
Quantifying inhomogeneous magnetic fields at the micrometer scale using graphene Hall-effect sensors
Authors: Petit Lionel , Blon Thomas , Lassagne Benjamin
Published: December 2024

The response of a graphene Hall-effect sensor to the inhomogeneous magnetic field generated by a dipole located above it is investigated numerically at room temperature as a function of the dipole position and orientation and as a function of the sensor conduction regime, i.e., diffusive or ballistic. By means of dedicated models, we highlight that the correction factor α frequently used to relate the Hall voltage to the magnetic field averaged over the sensor area can be greatly improved in the high proximity situation enabled by the use of graphene, particularly in the ballistic regime. In addition, it is demonstrated that by fine-tuning the dipole position in the sensor plane, the Hall response becomes highly selective with respect to the dipole orientation. These analyses show that diffusive graphene Hall sensors may be preferred for particle detection, while ballistic ones used as close as possible to a nanomagnet would be preferred for magnetometry. Then, with the help of micromagnetic simulations, the principle of measuring the magnetic hysteresis loop of an isolated nanomagnet with a ballistic Hall sensor is investigated. A large signal-to-noise ratio is demonstrated, which allows for effective probing of magnetization reversal. This shows that devices based on specially designed ballistic graphene Hall crosses promise to outperform state-of-the-art ballistic Hall sensors based on semiconductor quantum wells or micro-SQUID, especially for nano-magnetometry.
Frequency-dependent conductivity of concentrated electrolytes: A stochastic density functional theory
Authors: Bonneau Haggai , Avni Yael , Andelman David , Orland Henri
Published: December 2024

The response of ionic solutions to time-varying electric fields, quantified by a frequency-dependent conductivity, is essential in many electrochemical applications. Yet, it constitutes a challenging problem due to the combined effect of Coulombic interactions, hydrodynamics, and thermal fluctuations. Here, we study the frequency-dependent conductivity of ionic solutions using a stochastic density functional theory. In the limit of small concentrations, we recover the classical Debye and Falkenhagen (DF) result, predicting an increase in conductivity with field frequency. At higher concentrations, we use a modified Coulomb interaction potential that accounts for the hard-core repulsion between the ions, which was recently employed in the zero-frequency case. Consequently, we extend the DF result to concentrated electrolytes. We discuss experimental and numerical studies and the complexity of observing the DF effect in such setups.
Band alignment characterizations of grafted GaAs/(2¯01) Ga2O3 heterojunction via x-ray photoelectron spectroscopy
Authors: Lu Yi , Zhou Jie , Khandelwal Vishal , Adamo Carolina , Marshall Patrick , Gong Jiarui , Liu Yang , Ng Tien Khee , Li Xiaohang , Ooi Boon S. , Gambin Vincent , Ma Zhenqiang
Published: December 2024

Research on gallium oxide (Ga2O3) has accelerated due to its exceptional properties, including an ultrawide bandgap, native substrate availability, and n-type doping capability. However, significant challenges remain, particularly in achieving effective p-type doping, which hinders the development of Ga2O3-based bipolar devices like heterojunction bipolar transistors (HBTs). To address this, we propose integrating mature III–V materials, specifically n-AlGaAs/p-GaAs as the emitter (E) and base (B) layers, with n-Ga2O3 as the collector (C) to form III–V/Ga2O3 n–p–n HBT. This hetero-material integration could be achieved using advanced semiconductor grafting techniques that could create arbitrary lattice-mismatched heterojunctions by introducing an ultrathin dielectric interfacial layer. This study focused on revealing the band alignment at the base–collector (B–C) junction using a n-Ga2O3(2¯01) orientated substrate combined with p-GaAs for potential HBT applications. We discovered a type-II band alignment between p-GaAs and Ga2O3(2¯01), with the p-GaAs conduction band approximately 0.614 eV higher than that of Ga2O3(2¯01). This staggered alignment allows for direct and efficient electron transport from the p-GaAs base to the n-Ga2O3 collector, avoiding the electron blocking issues present in p-GaAs/Ga2O3 (010) heterojunctions. Additionally, our study suggests the potentially existing type-II alignment between the (2¯01) and (010) Ga2O3 interfaces, highlighting the orientation-dependent band offsets. These findings are pivotal for developing high-performance Ga2O3-based HBTs, leveraging the strengths of Ga2O3 and well-established semiconductor materials to drive advancements in high-power electronics.
One-dimensional ionic-bonded structures in NiSe nanowire
Authors: Liu Xiaozhi , Gao Ang , Zhang Qinghua , Wang Yaxian , Zhang Yangyang , Li Yangfan , Zhang Xing , Gu Lin , Hu Jinsong , Su Dong
Published: December 2024

One-dimensional van der Waals (1D vdW) materials, characterized by atomic chains bonded ionically or covalently in one direction and held together by van der Waals (vdW) interactions in the perpendicular directions, have recently gained intensive attention due to their exceptional functions. In this work, we report the discovery of one-dimensional (1D) ionic-bonded structures in NiSe nanowires. Utilizing aberration-corrected scanning transmission electron microscopy, we identified four distinct structural phases composed of two fundamental 1D building blocks: a triangle-shaped unit and a parallelogram-shaped unit. These phases can transform into one another through topotactic combinations of the structural units. Density functional theory calculations reveal that these structural units are bound by ionic bonds, unlike the van der Waals forces typically found in 1D vdW materials. The diverse arrangements of these building blocks may give rise to unique electronic structures and magnetic properties, paving the way for designing advanced materials with desired functionalities.
Multiple-quantum magic-angle spinning NMR spectra in the static limit: The I = 3/2 case
Authors: McCarthy-Carney Lexi , Wilson Brendan , Srivastava Deepansh , Baltisberger Jay H. , Grandinetti Philip J.
Published: December 2024

A simplified theoretical description of multiple-quantum excitation and mixing for nuclear magnetic resonance of half-integer quadrupolar nuclei is presented. The approach recasts the multiple-quantum nutation behavior in terms of reduced excitation and mixing curves through a scaling of the first-order offset frequency by the quadrupolar coupling constant. The two-dimensional correlation of the static first-order anisotropic line shape to the second-order anisotropic magic-angle-spinning (MAS) line shape is utilized to transform the three-dimensional integral over the three Euler angles into a single integral over the dimensionless first-order offset parameter. These transformations lead to a highly efficient algorithm for simulating the multiple-quantum (MQ)-MAS spectrum for arbitrary excitation and mixing radio frequency (RF) field strengths, pulse durations, and MAS rates within the static limit approximation, which is defined in terms of the rotation period, pulse duration, RF field strength, and quadrupolar coupling parameters. This algorithm enables a more accurate determination of the relative site populations and quadrupolar coupling parameters in a least-squares analysis of MQ-MAS spectra. Furthermore, this article examines practical considerations for eliminating experimental artifacts and employing affine transformations to improve least-squares analyses of MQ-MAS spectra. The optimum ratio of RF field strength to the quadrupolar coupling constant and the corresponding pulse durations that maximize sensitivity within experimental constraints are also examined.
Approximate calculation of backpropagated energy spectrum for a proton beam
Authors: Nichelatti E. , Piccinini M. , Ampollini A. , Astorino M. D. , Bazzano G. , Nenzi P. , Surrenti V. , Trinca E. , Ronsivalle C.
Published: December 2024

In certain experimental setups used for proton irradiations at the TOP-IMPLART linear accelerator at the ENEA Frascati Center, the energy spectrum of the proton beam is measured at the end of a propagation path, which includes transmission through different materials, such as air, windows, slabs, etc. In this paper, we develop and test an approximate mathematical method to calculate the energy spectrum at the accelerator exit from such a measured transmitted spectrum. In the first experimental test application, the spectrum measurement exploits the visible photoluminescence of F2 and F3+ color centers generated in lithium fluoride crystals by the interaction of the crystal lattice with protons. In the second test application, a simulated measurement of a propagated energy spectrum along a transport line is considered. In principle, the proposed method is applicable to the energy spectra of proton beams measured in any manner.
Role of lattice distortion on spallation of CoCrCuFeNi high-entropy alloy
Authors: Fang Jingzhong , Li Run , Yao Songlin , Chen Jun , Wang Kun
Published: December 2024

High-entropy alloys (HEAs), known for their high strength and enhanced ductility, have promising applications across various fields. Lattice distortion is a key factor in their strengthening, yet its role in dynamic fracture strength or spall strength remains unclear. This study employs large-scale nonequilibrium molecular dynamics simulations to investigate the dynamic responses of equiatomic CoCrCuFeNi HEA under shock velocities ranging from 0.6 to 1.45 km/s. By comparing the systems described using an average-atom interatomic potential, we uncover the role of lattice distortion. Our results reveal that spall strength exhibits complex behavior depending on the HEA's shock response. As shock velocity increases, the deformation mechanism transitions from elastic to dislocation and stacking fault (SF) dominated, eventually leading to a face-centered cubic to body-centered cubic phase transition. Lattice distortion significantly alters the active slip planes of dislocations and SFs, resulting in more SF intersections, while its effect on compression-induced phase transition is minor. During shock-induced spallation, residual defects after decompression significantly affect spall strength. Lattice distortion introduces additional stress and strain concentration sites, facilitating void formation and reducing spall strength. The temperature at the spall region is identified as a major factor governing spall strength variation under different shock velocities. Although lattice distortion can mitigate the softening effect of elevated temperature, it ultimately reduces spall strength, challenging the traditional views on its strengthening role. Moreover, the effects of lattice distortions on spall strength are quantified in terms of lattice misfit under varying loading strain rates and initial temperatures.
Ionotronic oxide neuromorphic transistor with pair-, triplet-, and quadruplet-spike-timing-dependent plasticity activities
Authors: Gong Bei Chen , Wang Wei Sheng , Zhou Si Yuan , Di Jia Kang , Huang Xin , Huang You Jie , Xiao Hui , Zhu Li Qiang
Published: December 2024

Electrolyte-gating poses a unique strategy to modulate physical characteristics and electronic transport properties of condensed materials. Here, solution-processed chitosan-based electrolyte-gated oxide ionotronic neuromorphic transistors are fabricated. Benefitting from unique protonic interfacial coupling processes, the ionotronic transistors can mimic different kinds of spike-timing-dependent plasticity (STDP), including the classical pair-STDP rule, triplet-STDP, and quadruplet-STDP. The triplet-STDP activities could be well explained with Froemke's triplet-STDP model, which proved to be effective in the biological nerve system. The oxide ionotronic neuromorphic transistors could act as fundamental building blocks in neuromorphic platforms.
Investigation of the origin of atomic-like emission at 4.09 eV from h-BN by correlating PL and XPS spectra
Authors: Maharjan N. , Joshi P. , Janzen E. , Edgar J. H. , Nakarmi M. L.
Published: December 2024

Deep ultraviolet (UV) photoluminescence (PL) and x-ray photoemission spectroscopy (XPS) were employed to investigate the origin of the atomic-like emission line at 4.09 eV from hexagonal boron nitride (h-BN) single crystals. High resolution XPS spectra analyzed by correlating PL spectra of the h-BN samples with and without the sharp emission line at 4.09 eV showed that carbon is bonding to both boron and nitrogen in the sample that has the 4.09 eV emission line. Our results showed that the defect responsible for the origin of the 4.09 eV line from h-BN is carbon related and it suggests that the defect structure has elemental carbon occupying both boron (CB) and as nitrogen (CN) sites.
Large cryogenic magnetocaloric effect in transition metal-based double dinitrates
Authors: Chen Zuhua , Zhang Chengliang , Zhang Zhengming , Lu Haiming , Wu Linglu , Zhang Guochun , Tu Heng , Li Zhenxing , Shen Jun , Wang Dunhui
Published: December 2024

Exploring paramagnetic salts with weak magnetic interactions and large saturation magnetic moments is of great significance in the field of cryogenic magnetic refrigeration. In this article, the first-principles calculation is performed to predict the magnetocaloric effect (MCE) of La-transition metal-based double nitrate hydrated salts. Through the comparison of the calculation results, La2Mn3(NO3)12·24H2O (LMnN) is chosen for further research on cryogenic magnetic refrigeration. The magnetic measurements reveal a weak antiferromagnetic interaction and large saturation magnetic moment of 4.95 μB of LMnN, which are consistent with theoretical calculation results. In addition, the maximum magnetic entropy change of LMnN is calculated to be 26.61 J kg−1 K−1 under a magnetic field change of 7 T at 2.5 K, which is greater than that of another double nitrate hydrated salts La2Co3(NO3)12·24H2O (LCoN). Excellent MCE verifies the rationality of first-principles calculation and suggests that LMnN is a promising hydrated paramagnetic salt for cryogenic magnetic refrigeration.
Impact of etching conditions on the sidewall quality of InGaN/GaN micro-LEDs investigated by cathodoluminescence imaging
Authors: Wolter Stefan , Agluschewitsch Vladislav , Wolter Silke , Lüßmann Frederik , Margenfeld Christoph , Schöttler Georg , Hartmann Jana , Waag Andreas
Published: December 2024

As micro-LEDs are further miniaturized for applications in high-resolution displays, size is becoming increasingly important for overall efficiency. To achieve high internal quantum efficiency, non-radiative recombination processes at the sidewall must be well understood and adequately mitigated. For this purpose, blue InGaN/GaN micro-LEDs were defined under two different dry etching conditions by changing the plasma power and Ar/Cl2 ratio, resulting in LEDs that were either stronger physically etched or stronger chemically etched. The LEDs were investigated using monochromatic cathodoluminescence imaging and time-resolved cathodoluminescence to determine how the etching conditions affect the detrimental influence of the sidewall on the quantum efficiency. A significant reduction of cathodoluminescence intensity and lifetime of the stronger physically etched structure from the bulk material toward the sidewall is observed, which is caused by an increase in the non-radiative recombination activity. Conversely, the stronger chemical etching conditions do not lead to a considerable degradation of the luminescence properties near the sidewall, which is attributed to the passivation of near-surface point defects with hydrogen during the etching process. This is corroborated by the intentional depassivation of such defects by low-energy electron beam irradiation or thermal annealing in an inert gas atmosphere leading to a similar efficiency deterioration, as well as by the recovery of efficiency by hydrogen plasma treatment. Overall, the results demonstrate that hydrogen can very effectively restore the efficiency of micro-LEDs at the sidewall. Therefore, the possible influence of hydrogen on the point defects at the sidewall should be considered in future studies investigating sidewall treatments.
Eliminating resistance measurement error due to thermoelectric effects in micro four-point probe measurements
Authors: Lamba Neetu , Guralnik Benny , Prado-Gonjal Jesús , Powell Anthony V. , Pryds Nini , Hansen Ole , Petersen Dirch H. , Beltrán-Pitarch Braulio
Published: December 2024

The micro four-point probe (M4PP) technique has become a well-established method for characterizing the electrical properties of materials. However, extra attention must be paid when measuring the resistivity of thermoelectric materials due to the possibility of an additional Seebeck voltage. This issue vanishes when measuring at a sufficiently high frequency, but the threshold frequency is substantial due to the small separation between the pins of the probes. Typical M4PP measurements are far from reaching this frequency, and their accuracy on thermoelectric materials is severely compromised. In this work, we explain the experimental conditions needed to measure reliably the electrical conductivity of thermoelectric materials and present a new method for measuring this property that reduces the frequency requirements by two orders of magnitude. The method is proven using two skutterudites and bismuth telluride material. It is also found that the resistance overestimation in the bismuth telluride sample is larger than that in the skutterudites due to its superior thermoelectric properties; the overestimate reaching 35%. The advances reported here enable the M4PP technique to be used for the measurement of the electrical conductivity of thermoelectric materials.
Experimental and numerical investigation of spray characteristics of gas–liquid swirl coaxial injectors
Authors: Cao Pengjin , Cui Chengchao , Bai Xiao , Li Ziguang , Li Qinglian , Cheng Peng
Published: December 2024

To investigate the velocity distribution and atomization characteristics of gas–liquid swirl coaxial (GLSC) injectors, atomization experiments and simulations were conducted under atmospheric conditions. The velocity distribution and morphology of the spray from GLSC injectors at varying gas–liquid ratios were measured using particle image velocimetry. The gas–liquid interaction, breakup dynamics, and the velocity of liquid sheet were simulated based on the three-dimensional volume of fluid to discrete particle model (VOF-to-DPM) and octree adaptive mesh refinement. Additionally, a method for extracting droplet diameters from high-quality images has been developed and validated. The results indicate that the sprays maintain a stable cone when the gas–liquid ratio is low. As the gas–liquid ratio increases, particularly at larger recess ratios, self-pulsation phenomena occur. During self-pulsation, the spray cone angle is enlarged, and the breakup length shortens. In a stable spray field, the center exhibits a low velocity region (5–10 m/s), while the spray periphery shows a high velocity region (20–25 m/s). Self-pulsation is induced by the “Klystron effect,” which arises from the Kelvin–Helmholtz (K–H) instability at the gas–liquid interface. The center of the self-pulsated spray transitions to a high velocity region due to the accelerated droplet motion driven by the annular gas flow through the spray's center. The radial distribution of mean droplet diameters for both stable and self-pulsated sprays has been summarized. As the gas–liquid ratios and recess ratios increase, the global droplet diameters gradually decrease, with a 75% of droplet diameters falling between 0 and 0.1 mm.
Performance of a tip shroud with film cooling and labyrinth seals
Authors: Yang Shaoyun , Du Wei , Luo Lei , Yan Han , Wang Songtao
Published: December 2024

The use of the tip shrouds is effective in reducing leakage flow. Film cooling is required to keep the hot gas separated from the shroud surface. This paper investigates the effects of film cooling on the cooling effectiveness and aerodynamic performance of a shrouded turbine cascade by numerical calculations. The flow structures of a single-side labyrinth seal and a double-side labyrinth seal are analyzed in detail, respectively. Compared to the unshrouded cascade, they reduced relative leakage by 27.1% and 49.7%, respectively. The introduction of coolant enhanced the sealing ability. Due to the recirculation zone, the cooling effectiveness at the shroud surface of the single-side labyrinth seal and double-side labyrinth seal is 0.0634 and 0.0481 at the blowing ratio of 0.5, respectively, and 0.0852 and 0.0759 at the blowing ratio of 1. Compared to the conditions without film cooling, the average total pressure loss at the outlet of the shrouded cascade with a single-sided labyrinth seal increased by 3.35% and 1.82% at blowing ratios of 0.5 and 1, respectively. For the shrouded cascade with a double-sided labyrinth seal, the total pressure loss increased by 2.23% and 2.20% at the same blowing ratios.
Large switchable polarization and piezoelectricity in multiferroic BiFeO3-Bi0.5K0.5TiO3-based single crystals
Authors: Yin Li-Hua , Tong Peng , Yang Jie , Song Wenhai , Sun Yuping
Published: December 2024

We report the structural, ferroelectric (FE), piezoelectric, and converse magnetoelectric (ME) effects in a series of Cr/Mn doped BiFeO3-Bi0.5K0.5TiO3-based (BF-BKT) single crystals. The Cr and Mn co-doped BF-BKT crystal (i.e., CrMn04) shows a large switchable polarization of 12ΔP ∼ 59.4 μC/cm2 and large-signal piezoelectric coefficient d33* at room temperature, and nearly thermally stable piezoelectric coefficient of d33 ∼ 212 pC/N below depolarization temperature Td ∼ 358.7 °C. A high DC resistivity of ρ > ∼1.0 × 105 Ω cm for T < ∼346.5 °C was also observed in CrMn04 crystal. All samples exhibit coexistent antiferromagnetic and FE orders and evident electric control of magnetism. The simultaneous existence of good performance of ferroelectricity, piezoelectricity, and converse ME effects in especially the CrMn04 crystal suggests its potential application in multi-functional devices.
An innovative coal permeability model based on elastoplastic mechanics: Development and verification
Authors: Wang Hengyu , Li Bobo , Li Jianhua , Ren Chonghong , Ye Pingping , Bai Yaozong
Published: December 2024

With the continuous mining of shallow coal resources, deep mining has increasingly become the norm. However, the migration mechanism of coalbed methane (CBM) in coal seams becomes exceptionally complex due to the combined influence of multiple factors in deep mining, posing considerable challenges to coal and gas co-mining. Therefore, studying the coal's mechanical behavior and seepage evolution mechanisms during deep mining is necessary. This study established a coal permeability model based on elastoplastic mechanics, considering the impacts of coal matrix destruction on the average fracture aperture. It assumed that the fracture aperture follows an exponential distribution and further introduced plastic strain to characterize the damage process in coal. The proposed permeability model was validated using the indoor experimental data. Subsequently, the control mechanisms of force-heat coordination effects on coal permeability were discussed, and the sensitivity of model parameters was analyzed. The results demonstrated that the established permeability model effectively described the evolution of coal permeability under the combined impacts of temperature and effective stress. Moreover, the fracture number ratio (η) and the influence coefficient of plastic strain increment on the average fracture aperture (β) not only connected the dilation of microfractures and plastic deformation in coal but also effectively reflected the relationship between permeability and plastic deformation during the failure process of coal. The results presented in this paper contributed to understanding the evolution of permeability during coal and gas co-mining, which should be of great significance for reducing coal and gas outburst hazards.
3+1 formalism of the minimally extended varying speed of light model
Authors: Lee Seokcheon
Published: December 2024

The

3
+
1

formalism provides a structured approach to analyzing spacetime by separating it into spatial and temporal components. When applied to the Robertson–Walker metric, it simplifies the analysis of cosmological evolution by dividing the Einstein field equations into constraint and evolution equations. It introduces the lapse function N and the shift vector Ni
, which control how time and spatial coordinates evolve between hypersurfaces. In standard model cosmology, N = 1 and

N
i

=
0

for the Robertson–Walker metric. However, the N becomes a function of time when we apply the metric to the minimally extended varying speed of light model. This approach allows for a more direct examination of the evolution of spatial geometry and offers flexibility in handling scenarios where the lapse function and shift vector vary. In this manuscript, we derive the model’s N, Ni
, along with the constraint and evolution equations, and demonstrate their consistency with the existing Einstein equations. We have shown in a previous paper that the possibility of changes in the speed of light in the Robertson–Walker metric is due to cosmological time dilation. Through the

3
+
1

formalism, we can make the physical significance more explicit and demonstrate that it can be interpreted as the lapse function. From this, we show that the minimally extended varying speed of light model is consistent.
Performance-enhanced piezoelectric energy harvesting system induced by Karman vortex using concave pseudo-blunt body structure
Authors: Wang Yalan , Hu Can , Li Yubao , Guo Ruixue , Qi Lingfei
Published: December 2024

Piezoelectric energy harvesting is one of the important technologies for environmental monitoring sensors to realize self-power supply. In recent years, the technology of fluid-induced piezoelectric vibration energy harvesting for blunt body structures based on Karman vortex street effect has been widely studied. In order to further improve the efficiency of energy harvesting, a performance-enhanced method of Karman vortex street energy harvesting based on structural modification is proposed. Different pseudo-blunt bodies with concave surfaces are designed and combined with piezoelectric device to harvest energy. The finite element simulation results show that, compared with the cylindrical blunt body, the pseudo-blunt body with concave surface can enhance the turbulent action of the fluid and make the Karman vortex shedding more intense. Especially for the pseudo-blunt body with S-concave, the amplitude of Karman vortex street and the turbulent kinetic energy behind the pseudo-blunt is strongest. In addition, based on wind tunnel, the energy harvesting performance of Karman vortex behind a cylinder with different surface structures is experimentally studied. The experimental results show that the piezoelectric energy harvesting efficiency behind the cylindrical pseudo-blunt body with concave surface is better than that behind the cylindrical blunt body without concave surface. In particular, the S-concave pseudo-passivate has the best energy harvesting performance, with a peak output voltage of 23.6 V, an output voltage span of 31.2 V, a maximum current of up to 0.23 mA, and a maximum power density of up to 6.64 W m−3, which are 136% and 81% higher than that of the ordinary cylindrical passivate, with an increase in the maximum current of 155% and an increase in the optimal power density of 532%, respectively. The above results show that the concave-based pseudo-blunt body structure can effectively improve the efficiency of vortex energy harvesting using piezoelectric mechanism, which lays an important foundation for the development and application of piezoelectric vortex energy harvesting theory.
Picture Perfect: Photometric Transient Classification Using the ParSNIP Model with Roman Hourglass Simulations
Authors: Abdelhadi Belal , Rubin David
Published: December 2024

The Roman Space Telescope, equipped with a 2.4 m primary mirror and optical–NIR wide-field camera, promises to revolutionize our understanding of dark energy, exoplanets, and infrared astrophysics. One of the Roman Core Community Surveys is the High Latitude Time Domain Survey (HLTDS), which will measure more than 10,000 SN Ia light curves but obtain a fraction of this number with spectra. The remaining SNe will have to be photometrically classified to achieve the full potential of the Roman HLTDS. To investigate transient yields and classifications, Rose et al. updated the Photometric LSST Astronomical Time-series Classification Challenge (PLAsTiCC) framework (originally developed for the Vera Rubin Observatory) for the Roman HLTDS. This study leverages this Roman “Hourglass” data set to train and evaluate the ParSNIP (Parameterized Supernova Identification Pipeline) model. We employ this model to classify various transient types from photometric data, paying particular attention to the types most represented in the data set: normal SNe Ia, 91bg-like SNe Ia, SNe Iax, and CC SNe. The ParSNIP model's performance is assessed through confusion matrices and ROC curves across different redshift ranges. Our analysis reveals that while the model performs robustly at higher redshifts (with the AUC for classification varying between 0.9 and 0.95 in the range 0.5 ≲ z ≲ 2), its accuracy dips at the lowest redshifts of the survey, likely due to limited training data. These findings underscore the importance of ensuring adequate representation of classes in the training set. This work underscores the value of machine learning models for next-generation surveys, paving the way for future studies with the Roman Space Telescope for survey optimization, cosmological forecasts, and synergies with other surveys.
The use of Support Vector Machine learning method to predict moisture of building materials using the Time Domain Reflectometry
Authors: Suchorab Z , Mikušová D , Paśnikowska-Łukaszuk M , Juszczyński P , Trník A
Published: December 2024

This article shows the possibility to adopt Support Vector Machine (SVM) learning method to predict moisture of building materials measured by the Time Domain Reflectometry (TDR) method. TDR is an indirect technique of moisture detection. It enables to evaluate apparent permittivity of moist material and then predict moisture using physical or empirical models. In this research it is presented the method that avoids evaluation of apparent permittivity value and estimate moisture basing on the raw TDR waveforms. SVM is one of the most popular machine learning methods that could be used both for classification and regression modelling. It is mostly applied for analysing of multidimensional signals, but could be also applied to evaluate moisture from raw TDR signals. SVM regression model allows quick estimation of material moisture and achieve similar or better measurement accuracy comparing to the standard calibration methods. Research was conducted on two types of building materials – the red and the silicate bricks and data analysis confirmed the suitability of SVM models in determining moisture content using the TDR method.
Using the guarded axial heat flow method for heat flux meters calibration
Authors: Stepanić N , Milošević N
Published: December 2024

This paper proposes a practical solution for calibration of heat flux meters, typically used in assessment of energy efficiency of buildings, where specific heat flux values are usually below 100 Wm−2. Output signal of such sensors is dependent both on heat flux and temperature, while means for their calibration are currently limited to apparatuses operating according to the reference steady state thermal conductivity measurement methods. A guarded axial heat flow apparatus, that provides a measurable heat flux directed through the cross-section of disc-shaped sensors whose voltage response is acquired, may conveniently overcome some disadvantages of other steady state reference methods, primarily their time-consumption. A description of a heat flux meter calibration setup developed at the Institute VINČA is given in this paper. A key effect that significantly contributes to the calibration uncertainty is analyzed, as well as their corrections. Results of a calibration example are given in the last section.
FEM verification of natural convection loop model
Authors: Bulatović G , Bokes P
Published: December 2024

We compare the analytical results for a natural convection loop model with two-dimensional finite element method (FEM) simulations. We set the values for FEM simulations parameters to reflect oil circulation in a distribution transformer. We find that the calculated characteristics for the two approaches differ by less than 3%. This discrepancy is explained in terms of the variations in the fluid velocity profile.
The comparison of two polynomial regression models with one and two independent variables in moisture detection technique in building materials
Authors: Futa A , Jastrzębska M
Published: December 2024

The paper presents the depiction of moisture detection technique in building materials and contains two techniques of analysis including a detailed comparison of them. Namely, two models of polynomial regression models are presented: the first model with one independent variable and the second, multiple regression model, including two independent variables. The readouts describe the dependence between the moisture of building material evaluated gravimetrically and permittivity and signal voltage values designate by TDR technique. The correlation between the moisture content determined by the TDR and the moisture content appointed gravimetrically is presented. Based on the obtained data, two types of regression models are compared. The property and the quality of both models are discussed.
Optimized rad-hard DC/DC converters for HEP applications
Authors: van der Blij Nils H. , Koseoglou Sokratis , Bantemits Georgios , Ripamonti Giacomo , Michelis Stefano
Published: December 2024

The development of 48 V compatible DC/DC converters that are tolerant to high magnetic fields and radiation helps to reduce the cost and weight of the cabling, power supplies and cooling of High Energy Physics (HEP) experiments.
In this paper, a new, optimized and compact bPOL48V module is presented aimed at 48 V to 5–12 V power conversion.
This new module, which is available for purchase and as a reference design, reduces the size by 93% compared to previous designs while exhibiting similar efficiency.
Furthermore, a framework for optimizing and comparing converter topologies is also introduced, which identifies the 3-level buck topology as a promising topology for future research and development.
Moreover, experimental validation of different optimized converters is also provided.
The experimental results show that the 3-level buck topology is promising for 48 V to 5 V conversion stages, and that the Berkeley buck topology is promising for the development of 48 V to 1 V conversion stages.
Investigation of non-idealities of pulsing circuitry in the ALICE ITS3 MOSS monolithic sensor
Authors: Emiliani S. , Aglieri Rinella G. , Lemoine C. , Piro F. , Ripamonti G. , Snoeys W. , Suljic M. , Terlizzi L.
Published: December 2024

The MOSS wafer-scale monolithic sensor, designed for the vertex detector (ITS3) of the ALICE experiment, features a pixel input capacitance of ∼ 5 fF. Such a small input capacitance is needed to reach a satisfactory SNR with a low-power analog front-end (36 nW/pixel). This makes the design of the pulsing circuitry needed to characterize the front-end performance particularly challenging. As an example, measurements of the front-end of MOSS are presented, showing that even a parasitic capacitance less than 5 aF can significantly alter the charge injection from the pulsing circuit. In this contribution, design methods and solutions to address these challenges are detailed.
Biocompatible TA4 and TC4ELI with excellent mechanical properties and corrosion resistance via multiple ECAP
Authors: Li Liangzhong , Hao Liyu , Zhang Shuangle , Shen Shangkun , Liu Xing , Fu Engang
Published: December 2024

Titanium (Ti), characterized by its exceptional mechanical properties, commendable corrosion resistance and biocompatibility, has emerged as the principal functional materials for implants in biomedical and clinical applications. However, the Ti-6Al-4V (TC4ELI) alloy has cytotoxicity risks, whereas the strength of the existing industrially pure titanium TA4 is marginally inadequate and will significantly limit the scenarios of medical implants. Herein, we prepared ultrafine-grained industrial-grade pure titanium TA4 and titanium alloy TC4ELI via the equal channel angular pressing method, in which the TA4-1 sample has ultrahigh strength of 1.1 GPa and elongation of 26%. In comparison with the micrometer-crystalline Ti-based materials, it showed a 35% reduction in wear depth and more than 10% reduction in wear volume, while the difference in the corrosion potential of the simulated body fluids was not significant (only ∼20 mV). XRD, electron backscatter diffraction, and transmission electron microscope characterization confirms that their superior strengths are mainly due to grain refinement strengthening.
Green hydrogen in the iron and steel industry increases resilience against shocks in energy prices
Authors: Leuratti Nicola , Marangoni Giacomo , Drouet Laurent , Kamp Linda M , Kwakkel Jan
Published: December 2024

Geopolitical tensions and conflicts can disrupt energy markets, threatening international energy supply security and imposing financial stress on energy-intensive industries reliant on imported fossil fuels. Exploring the challenges and opportunities associated with supply diversification is crucial for understanding the potential for hard-to-abate industry decarbonization under the risk of future energy price shocks. In this context, we investigate the role of green hydrogen as a viable and sustainable alternative to natural gas applications in iron and steel manufacturing. We first quantify how the integration of green hydrogen into the existing infrastructure can complement stringent climate action ambitions in reducing CO2 emissions over the next five decades. We find that green hydrogen acts as a transitional technology, enabling a gradual shift towards electrification of heat supply while bridging the gap until low-carbon steel technologies become commercially feasible. Furthermore, we assess the benefits of timely green hydrogen investments in mitigating the economic repercussions of unforeseen natural gas price surges. Overall, this study underscores the potential of green hydrogen in decarbonizing the iron and steel industry while promoting energy independence, but it also highlights its contingency on sufficiently ambitious climate policies and adequate technological advancements.
Cryptocurrencies investing trends in the context of Environmental, Social and Governance
Authors: Juškaitė L , Tamošiūnienė R
Published: December 2024

The changing environment forces investors to evaluate investments not only from a financial point of view, but also in terms of environmental, social and governance (ESG). Cryptocurrencies are no exception in this case. There are still a few cryptocurrency studies that are designed to evaluate cryptocurrencies and investments in them in the context of ESG. The purpose of this topic is to define theoretically the compliance of investing in cryptocurrencies with ESG criteria by identifying research trends. This study uses scientific literature and bibliometric analysis to investigate the relevance and trends of the field of investments in cryptocurrencies in the context of ESG.