bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling and simulation of grain growth for FGH96 superalloy using a developed cellular automaton model
Authors: Yang Yanhui , Zhang Boyan , Chen Xiuquan , Wang Xiaoxuan , Sun Jingshi
Published: April 2024

Through heat treatment experiments and numerical simulations, the effects of the heating temperature (1313–1423 K) and holding time (10–240 min) on the grain growth behavior of the extruded FGH96 alloy were investigated. A two-dimensional cellular automata (CA) model that considered the dissolution of the γ′ phase over time and the distribution characteristics with different sizes was developed to explore the grain growth behavior above the γ′ phase over-solution temperature (1423 K) and below the γ′ sub-solution temperature (1383 K), respectively. The results showed that the rate of grain growth of FGH96 alloy was obviously enhanced when the heating temperature exceeded 1363 K, which was mainly related to the dissolution of the γ′ phase, and the grain growth of FGH96 alloy mainly occurred during the initial stage of insulation. The grain growth model of the extruded FHG96 alloy could accurately predict the grain growth behavior, and the simulation results were in good agreement with the experimental results at over-solution temperature or sub-solution temperature. The effects of volume fraction and radius of γ′ phase on the grain growth behavior of FGH96 alloy were studied by simulating the grain growth behavior of FGH96 alloy under different sizes and volume fractions of γ′ phase. The results follow the Zener relation, and the coefficient n in the Zener relation was determined by fitting the simulation results.
Artificial neural network-based approach for prediction of nanomechanical properties of anodic coating on additively manufactured Al–10Si–Mg alloy
Authors: Ghosh Rahul , Sahu Bhavana , Dey Arjun , Thota Hari Krishna , Das Karabi
Published: April 2024

Nowadays, anodic coating on additively manufactured (AM) or 3D printed Al–10Si–Mg alloy are used for various components in spacecraft such as antenna feeds, wave guides, structural brackets, collimators, thermal radiators etc. In this study, artificial neural network (ANN) and power law-based models are developed from experimental nanoindentation data for predicting elastic modulus and hardness of anodized AM Al–10Si–Mg at any desired loads. Data from nanoindentation experiments conducted on plan- and cross-sections of anodized coating on AM Al–10Si–Mg alloy was considered for modeling. Apart from nanomechanical properties, load and displacement curves were predicted using Python software from ANN and the Power law model of nanoindentation. It is observed that the ANN model of 50 mN nanoindentation experimental data can accurately predict the loading pattern at any desired load below 50 mN. Elastic modulus and hardness of anodized AM Al–10Si–Mg computed from ANN and the power law model of the unloading curve are also comparable with the values obtained from Weibull distribution analysis reported elsewhere. The derived models were also used to predict nanomechanical properties at 25 and 35 mN, for which no experimental data was available. The computed hardness of plan section of the anodic coating is 3.99 and 4.02 GPa for 25 and 35 mN, respectively. The computed hardness of cross-section of the anodic coating of is 7.16 and 6.61 GPa for 25 and 35 mN, respectively. Thus, the ANN and Power law model of nanoindentation can predict elastic modulus and hardness at different loads by conducting the minimum number of experiments. The novel approach to predict nanomechanical properties using ANN resulted in determining realistic and design specific data on hardness and modulus of the anodized coating on AM Al–10Si–Mg alloy.
Colour and temperature of the stars: a demonstration using Arduino
Authors: Hahn Marcelo Dumas , Carvalho Paulo Simeão , Cruz Frederico Alan de Oliveira
Published: April 2024

Teaching the colour of stars is not as trivial as one might think. It can be challenging for students to grasp that the colour of stars follows a temperature sequence. This paper introduces a simple experimental setup for instructing the correlation between a star’s colour and its temperature. Furthermore, the experimental setup facilitates the exploration of the topic of colour addition, demonstrating to students how to replicate the colour of a star—a spectrum colour—by employing an RGB LED that emits only primary colours (red, green, and blue). The experiment utilised an Arduino microcontroller board in conjunction with RGB LEDs and an LCD display. The activity was conducted with 53 7th-grade students from a private school in Portugal results suggest a positive reception, indicating success in both motivational and cognitive aspects. The overall outcomes underscore the effectiveness of the activity in imparting new knowledge to students.
Dosimetric evaluation of different planning strategies for hypofractionated whole-breast irradiation technique
Authors: Tang Chunbo , Liu Biaoshui , Yuan Jun , He Ji , Xie Ruilian , Huang Minfeng , Niu Shanzhou , Liu Hongdong
Published: April 2024

Purpose. The dose hotspot areas in hypofractionated whole-breast irradiation (WBI) greatly increase the risk of acute skin toxicity because of the anatomical peculiarities of the breast. In this study, we presented several novel planning strategies that integrate multiple sub-planning target volumes (sub-PTVs), field secondary placement, and RapidPlan models for right-sided hypofractionated WBI. Methods. A total of 35 cases of WBI with a dose of 42.5 Gy for PTVs using tangential intensity-modulated radiotherapy (IMRT) were selected. Both PTVs were planned for simultaneous treatment using the original manual multiple sub-PTV plan (OMMP) and the original manual single-PTV plan (OMSP). The manual field secondary placement multiple sub-PTV plan (m-FSMP) with multiple objects on the original PTV and the manual field secondary placement single-objective plan (m-FSSP) were initially planned, which were distribution-based of V105 (volume receiving 105% of the prescription dose). In addition, two RapidPlan-based plans were developed, including the RapidPlan-based multiple sub-PTVs plan (r-FSMP) and the RapidPlan-based single-PTV plan (r-FSSP). Dosimetric parameters of the plans were compared, and V105 was evaluated using multivariate analysis to determine how it was related to the volume of PTV and the interval of lateral beam angles (ILBA). Results. The lowest mean V105 (5.64 ± 6.5%) of PTV was observed in m-FSMP compared to other manual plans. Upon validation, r-FSSP demonstrated superior dosimetric quality for OAR compared to the two other manual planning methods, except for V5(the volume of ipsilateral lung receiving 5 Gy) of the ipsilateral lung. While r-FSMP showed no significant difference (p = 0.06) compared to r-FSSP, it achieved the lowest V105 value (4.3 ± 4.5%), albeit with a slight increase in the dose to some OARs. Multivariate GEE linear regression showed that V105 is significantly correlated with target volume and ILBA. Conclusions. m-FSMP and r-FSMP can substantially enhance the homogeneity index (HI) and reduce V105, thereby minimizing the risk of acute skin toxicities, even though there may be a slight dose compromise for certain OARs.
Brain elastography in aging relates to fluid/solid trendlines
Authors: Parker Kevin J , Kabir Irteza Enan , Doyley Marvin M , Faiyaz Abrar , Uddin Md Nasir , Flores Gilmer , Schifitto Giovanni
Published: April 2024

The relatively new tools of brain elastography have established a general trendline for healthy, aging adult humans, whereby the brain’s viscoelastic properties ‘soften’ over many decades. Earlier studies of the aging brain have demonstrated a wide spectrum of changes in morphology and composition towards the later decades of lifespan. This leads to a major question of causal mechanisms: of the many changes documented in structure and composition of the aging brain, which ones drive the long term trendline for viscoelastic properties of grey matter and white matter? The issue is important for illuminating which factors brain elastography is sensitive to, defining its unique role for study of the brain and clinical diagnoses of neurological disease and injury. We address these issues by examining trendlines in aging from our elastography data, also utilizing data from an earlier landmark study of brain composition, and from a biophysics model that captures the multiscale biphasic (fluid/solid) structure of the brain. Taken together, these imply that long term changes in extracellular water in the glymphatic system of the brain along with a decline in the extracellular matrix have a profound effect on the measured viscoelastic properties. Specifically, the trendlines indicate that water tends to replace solid fraction as a function of age, then grey matter stiffness decreases inversely as water fraction squared, whereas white matter stiffness declines inversely as water fraction to the 2/3 power, a behavior consistent with the cylindrical shape of the axons. These unique behaviors point to elastography of the brain as an important macroscopic measure of underlying microscopic structural change, with direct implications for clinical studies of aging, disease, and injury.
Contrast-enhanced photon-counting micro-CT of tumor xenograft models
Authors: Li Mengzhou , Guo Xiaodong , Verma Amit , Rudkouskaya Alena , McKenna Antigone M , Intes Xavier , Wang Ge , Barroso Margarida
Published: April 2024

Objective. Photon-counting micro-computed tomography (micro-CT) is a major advance in small animal preclinical imaging. Small molecule- and nanoparticle-based contrast agents have been widely used to enable the differentiation of liver tumors from surrounding tissues using photon-counting micro-CT. However, there is a notable gap in the application of these market-available agents to the imaging of breast and ovarian tumors using photon-counting micro-CT. Herein, we have used photon-counting micro-CT to determine the effectiveness of these contrast agents in differentiating ovarian and breast tumor xenografts in live, intact mice. Approach. Nude mice carrying different types of breast and ovarian tumor xenografts (AU565, MDA-MB-231 and SKOV-3 human cancer cells) were injected with ISOVUE-370 (a small molecule-based agent) or Exitron Nano 12000 (a nanoparticle-based agent) and subjected to photon-counting micro-CT. To improve tumor visualization using photon-counting micro-CT, we developed a novel color visualization method, which changes color tones to highlight contrast media distribution, offering a robust alternative to traditional material decomposition methods with less computational demand. Main results. Our in vivo experiments confirm the effectiveness of this color visualization approach, showing distinct enhancement characteristics for each contrast agent. Qualitative and quantitative analyses suggest that Exitron Nano 12000 provides superior vasculature enhancement and better quantitative consistency across scans, while ISOVUE-370 delivers a more comprehensive tumor enhancement but with significant variance between scans due to its short blood half-time. Further, a paired t-test on mean and standard deviation values within tumor volumes showed significant differences between the AU565 and SKOV-3 tumor models with the nanoparticle-based contrast agent (p-values < 0.02), attributable to their distinct vascularity, as confirmed by immunohistochemical analysis. Significance. These findings underscore the utility of photon-counting micro-CT in non-invasively assessing the morphology and anatomy of different tumor xenografts, which is crucial for tumor characterization and longitudinal monitoring of tumor progression and response to treatments.
Suppression of equilibrium magnetic islands by density profile effect in quasi-axisymmetric stellarator plasmas
Authors: Fu T , Wang X Q , Su X , Xu Y , Okamura S , Shimizu A , Isobe M , Cheng J , Liu H F , Huang J , Zhang X , Liu H , Tang C J
Published: April 2024

In a quasi-axisymmetric stellarator, a significant bootstrap current will result in the generation of low-order rational surfaces and three-dimensional (3D) magnetic islands. In this paper, the influence of plasma density profiles on the equilibrium magnetic islands for the Chinese first quasi-axisymmetric stellarator (CFQS) is investigated using the HINT code. It is found that the flattening of the core plasma density profile leads to a significant suppression of magnetic islands. When the peaking factor of plasma density is 1.19, complete suppression of magnetic islands occurs while maintaining excellent integrity of the magnetic surface even with the volume-averaged plasma beta <β> increase up to 2%. On the other hand, during the transition of a plasma density profile from flat to hollow, there is a reversal in the core bootstrap current, resulting in reduction of rotational transform values to pass through the rational surface. Hence, formation of magnetic islands in the core region. Therefore, effective inhibition of CFQS’s magnetic islands can be achieved by appropriately controlling density profiles through methods like gas injection.
Plasma dynamics of individual HiPIMS pulses: imaging study using high-frame-rate camera
Authors: Panjan Matjaž
Published: April 2024

A high-frame-rate camera with microsecond-level time resolution was used to make systematic investigations of plasma self-organization and spoke dynamics during individual HiPIMS pulses. The plasma was imaged for a range of argon pressures (0.25–2 Pa) and peak discharge currents (10–400 A) using an Al target. The experiments revealed that plasma evolves through three characteristic stages as the discharge current increases. In stage I, which is present from the current onset and up to ∼25 A, spokes are azimuthally long and rotate in the −Ez
× B direction. The spoke behavior is similar to the one observed in DCMS discharges. The number of spokes depends on pressure and the current growth rate. At the lowest pressure (0.25 Pa) a single spoke is present in discharge, while at higher pressures (1–2 Pa) two spokes are most often observed. The spoke velocity depends on the number of spokes, current growth rate and pressure. A single spoke rotates with velocities in the 4–15 km s−1 range, while two spokes rotate in the 1–9 km s−1 range depending on the pressure and growth rate. Following stage I, the plasma undergoes a complex reorganization that is characterized by aperiodic spoke patterns and irregular dynamics. In stage II spokes are less localized, they merge, split and propagate either in the retrograde or prograde direction. After chaotic plasma reorganization, more ordered spoke patterns begin to form. Spokes in stage III are azimuthally shorter, typically exhibit a triangular shape and rotate in the Ez
× B direction. In general, the spoke dynamics is less complicated and is only influenced by the pressure. Spokes rotate faster at higher pressures than at lower ones; velocities range from 9 km s−1 at 0.25 Pa to 6 km s−1 at 2 Pa. The spoke velocity in stage III is largely unaffected by the discharge current or number of spokes. Stage III can be further divided into sub-stages, which are characterized by different current growth rates, spoke sizes and shapes. In general, the spoke evolution is highly reproducible for pulses with similar discharge current waveforms.
Rate-dependent energy dissipation of graded viscoelastic structures fabricated by grayscale vat photopolymerization
Authors: Valizadeh Iman , Weeger Oliver
Published: April 2024

A major benefit of additive manufacturing technologies is precise control over structural topologies and material properties, which allows to tailor, for instance, energy absorption and dissipation. While vat photopolymerization is generally restricted to a single material, grayscale masked stereolithography (gMSLA) allows to customize material behavior by grading the light intensity within a structure. This study investigates the impact and opportunities of grayscale grading strategies on the rate-dependent mechanical behavior of structures fabricated by gMSLA. Considering the viscoelastic nature of polymers, rate-dependent energy dissipation is explored, introducing a parametric linear viscoelastic constitutive model for varying grayscales. The investigation includes the comprehensive characterization of mechanical properties, numerical finite element simulation, validation through experimental procedures, and exploration of dissipation energy under different strain rates. In this way, a rational function successfully determines the critical strain rate at which the maximum dissipation occurs. Overall, the research offers a comprehensive investigation of the mechanical dissipation behavior of graded 3D printed structures, laying the foundation for further studies and advancements aimed at optimizing these structures for enhanced energy absorption capabilities.
A route to fabricate low resistance joints between Eu–Ba–Cu–O bulk, single grain superconductors
Authors: Congreve J V J , Shi Y , Tutt N C , Taylor R W , Bumby C , Dennis A R , Druiff H , Weerakonda Arachchilage D , Durrell J H , Cardwell D A
Published: April 2024

The fabrication of large (RE)–Ba–Cu–O single grains [(RE)BCO], where RE = Y, Gd, Eu or Sm, with the complex geometries required for many practical applications is currently limited by the time intensive, complex nature of the grain growth process. In addition, the shapes achievable using established melt processing techniques, such as top seeded melt growth, are constrained significantly by the limited number of post-processing techniques readily available. Machining of these materials is also difficult given their ceramic-like mechanical properties, which makes them both brittle and hard. A potential alternative to the slow and inflexible melt growth processes is to join many small, single grains to form one large composite grain, connected by electrically and mechanically high-performance joints. A reliable joining technique would also greatly reduce the need for post-growth machining processes. In this work we extend our previous investigation of the use of single grain YBCO-Ag as an intermediate joining material to achieve effective and reliable superconducting joints between EuBCO-Ag bulk, single grain superconductors. The technique reported in the earlier studies requires limited specialist equipment and does not require tight process parameter control, since there is no need to re-grow the joining material at the intergrain interface. This technique is of particular interest given that the difference between the peritectic temperatures of the bulk superconductor and the intermediate joining material is large. We report the properties of seven joints engineered at different joining temperatures. The trapped field properties of the resulting joined samples were measured and the microstructure at the position of the joint examined. We demonstrate that this simple and the rapid joining technique makes it possible to manufacture composite grains in an industrially important (RE)BCO bulk superconductor with comparable superconducting properties to those of a single grain of similar dimensions.
Spatiotemporal modulation of ultrafast plasmonic vortices with spin–orbit coupling
Authors: Li Weipeng , Zhang Shuoshuo , Zhou Zhangyu , Fu Yanan , Zhang Yuquan , Yuan Xiaocong , Min Changjun
Published: April 2024

The vortex field of surface plasmon polariton with orbital angular momentum (OAM), called plasmonic vortex, has played an important role in various research fields. However, the spatiotemporal properties of plasmonic vortex pulses excited by ultrafast laser, especially the dynamics of spin‒orbit coupling in the ultrafast plasmonic vortex field, have yet to be investigated deeply. Here, we study the spatiotemporal modulation of ultrafast plasmonic vortices with spin‒orbit coupling, using both analytical and simulation methods. The ultrafast plasmonic vortices are excited by a ring-shaped plasmonic lens, with an incident light composed of two time-delayed femtosecond sub-pulses carrying the same OAM but orthogonal circular polarizations. The dynamics of time-varying electric field, energy flow and angular momentum distributions of the plasmonic vortices are demonstrated, revealing details of the spin‒orbit coupling in spatiotemporal domain, such as the merging of multiple phase singularities with energy flow loops, and the variation of spin/orbital angular momentum per photon over time. This work could deepen the understanding of spin‒orbit coupling in plasmonic field and provide new ideas for ultrafast on-chip optical information processing.
Contribution of different electron-capture mechanisms in the fragmentation of CO

2

3
+

upon slow ion-molecule collisions
Authors: Kumar Kamal , Kalam Azad Siddiki Md Abul , Mukherjee Jibak , Singh Harpreet , Misra Deepankar
Published: April 2024

We present a recoil ion—projectile ion coincidence study on the three body fragmentation of

CO
2

3
+

ion into

C
+

+

O
+

+

O
+

fragments upon impact with

Ar

3
+

,
 

Ar

6
+

 
and
 

Ar

8
+

projectile ions having the same velocity of

v
p

=
0.49

a.u. (atomic units) using the recoil ion momentum imaging technique. The kinetic energy release (KER) distributions are presented and the effect of different electron-capture associated processes such as pure capture, electron capture followed by target-ionization or projectile auto-ionization is discussed based on the analysis of KER corresponding to different final projectile charge states post-collision. As the capture stabilization increased, the relative yields in the KER distribution are found to decrease in the high KER side for low charged

Ar

3
+

impact, while an increase is observed for

Ar

6
+

 
and
 

Ar

8
+

impacts. We discuss the interplay between electron-capture, projectile auto-ionization, and target ionization for the dominance of a particular process. We also observe a low-KER feature around 15 eV which was observed for electron and proton impacts, that has not yet been observed for highly charged ion impacts.
Particle transport along the circular trajectory of a semi-infinite Bessel acoustic beam
Authors: Zhou Qinxin , Ren Xuemei , Shi Yubo , Xu Zheng
Published: April 2024

We explored the propagation of semi-infinite accelerating Bessel beams along circular trajectories beyond the paraxial approximation. Until now, the complex nature of these beams has posed a challenge for the development of construction methods, resulting in primarily theoretical research within the field of acoustics. In this study, we successfully achieved experimental realization of these beams in the acoustic domain using our previously proposed acoustic Fourier transform system, which involves phase modulation through a holographic lens and Fourier transformation through a cylindrical focusing reflector. Our results demonstrate that these beams exhibit accelerated propagation along circular trajectories. Moreover, we experimentally generated and directly observed these highly curved beams during the transportation of micro-particles, where they undergo substantial bending at large angles.
Color image encryption algorithm based on novel dynamic DNA encoding and chaotic system*
Authors: Mou Dingkang , Dong Yumin
Published: April 2024

To enhance the security of image data, prevent unauthorized access, tampering, and leakage, maintain personal privacy, protect intellectual property rights, and ensure the integrity of images during transmission and storage. This study introduces an innovative color image encryption scheme based on dynamic DNA encoding operations and chaotic systems. By simulating a quantum random walk, a random key is generated to enhance the security of the confidential system. In addition, we integrated the enhanced Josephus problem into DNA coding rules to create dynamic DNA coding rules. At the same time, we proposed a dynamic double-loop DNA XOR operation, which fully utilizes the random sequence generated by the generalized Hamiltonian chaos system to precisely control the loop direction, starting point, and number of operations. This enhances the complexity of the encryption algorithm. After sufficient experimental verification and in-depth research and analysis, our innovative design not only enhances the difficulty of cracking while ensuring image quality but also provides reliable protection for the security of image data.
Enhanced smartphone connectivity: dual-band MIMO antenna with high isolation and low ECC
Authors: Abubakar Hassan Sani , Zhao Zhiqin , Munir Mehr E , Tareen Wajahat Ullah Khan , Wang Boning , Kiani Saad Hassan , Ali Tanweer
Published: April 2024

The research presents an eight-element dual-band modified T-shaped slot antenna array optimized for seamless integration into contemporary smartphones, addressing the burgeoning demands of 5G communication within the sub-6 GHz spectrum. Operating across two critical frequency bands spanning 3.37-3.61 GHz and 4.9-5.1 GHz, this advanced antenna system boasts impressive efficiency and performance metrics. Symmetrically arranged on the ground plane, each antenna element measures 20 × 11.8 mm2 (equivalent to 0.233 λ×0.138λ), with a notable design feature being the inclusion of section Dx, strategically positioned between the ground-mounted antennas to enhance isolation among radiating elements by effectively managing surface currents. Fabrication results showcase isolation levels surpassing -14 dB, with an Envelope Correlation Coefficient (ECC) lower than 0.05 in the lower frequency band and 0.02 in the higher band, indicating robust performance in mitigating mutual coupling effects. The antenna array exhibits exceptional efficiency ranging from 48.5% to 63.7%, coupled with a commendable channel capacity of 38.8 bps/Hz and a gain of 3.9 dBi, highlighting its suitability for integration into smartphone devices and its potential to advance the next generation of mobile communication technologies.
Enhanced self-collimation effect by low rotational symmetry in hexagonal lattice photonic crystals
Authors: Yuksel Zekeriya M , Oguz Hasan , Karakilinc Ozgur O , Turduev Mirbek , Berberoglu Halil , Adak Muzaffer , Ozdemir Kart Sevgi
Published: April 2024

In this study, we present the design of a photonic crystal (PC) structure with a hexagonal lattice, where adjustments to the PC unit cell symmetry reveal an all-angle self-collimation (SC) effect. By optimizing opto-geometric parameters, such as the rotational angle of auxiliary rods and adjacent distances, we analyze the SC property in detail, leveraging group velocity dispersion (GVD) and third-order dispersion (TOD) characteristics. We also investigate the relationship between symmetry properties and their influence on dispersion characteristics. Through symmetry manipulation, we gain a comprehensive understanding of the underlying mechanisms governing light collimation and confinement in the proposed configurations. The PC structure with a C1 symmetry group exhibits all-angle SC effect within the range of a/λ = 0.652 and a/λ = 0.668 normalized frequencies, with a bandwidth of Δω/ω

c

=2.4% Further breaking the symmetry, transforming from C1 to C2 group symmetry enhances the SC bandwidth to Δω/ω

c

=6.5% and reveals the perfect linear equi-frequency contours (EFC) at two different frequency bands: all angle SC between a/λ = 0.616 and a/λ = 0.344 normalized frequencies in the 4th transverse magnetic (TM) band and between a/λ = 0.712 and a/λ = 0.760 in the 5th TM band. Here, GVD and TOD values of the TM 4th band vary between 7.3 (a/2πc2)–254.3 (a/2πc2) and 449.2 (a2/4π
2c3)–1.3×105 (a2/4π
2c3), respectively. Also, GVD and TOD values of the TM 5th band vary between 182.5 (a/2πc2)–71.3 (a/2πc2) and −24380(a2/4π
2c3)–−9619 (a2/4π
2c3) values, respectively. Additionally, we propose a composite/hybrid PC structure resembling C2 group symmetry, where two auxiliary rods are replaced by rectangular photonic wires with the same refractive index and width equal to the diameter of auxiliary rods. This hybrid structure exhibits an all-angle SC effect with an operating bandwidth of Δω/ω

c

=11.7%, which displays near-zero GVD and TOD performance and offers enhanced robustness against potential fabrication precision issues.
Theoretical prediction of soft-forming micro-hemispherical shells from fused silica substrates in reclining mold
Authors: Yang Xiuhua , Xia Dunzhu , Li Jinhui , Chu Qingbo
Published: April 2024

A reclining mold can support the soft forming of fused silica substrates into micro-hemispherical shells with the same height, which makes the processing of micro-hemispherical shells attractive. Currently, it is difficult to determine the optimal process parameters for machining micro-hemispherical shells, and several iterations of experiments are required. This process wastes large amounts of substrate material, experimental consumables, and machining time, and increases the cost of the experiments. In this paper, we report a reflow process for soft-forming micro-hemispherical shells from fused silica substrates supported by a reclining mold. The shapes of the shells formed from the fused silica substrates in reclining and non-reclining molds were analysed by building a two-dimensional model. Moreover, we predicted the effects of varying the process parameters on the shell-forming time and geometrical parameters, as well as the stresses and deformations of the shells after cooling. The effect of the eccentricity of the central support column of the mold on the symmetry of micro-hemispherical shells was also investigated, and the influence of the mold and substrate heating inhomogeneity on micro-hemispherical shell formation was analysed. Additionally, the heat uniformity of the substrate in the rotating state was examined. Finally, we investigated the temperature field and thickness distribution during the shell-forming process through 3D modelling to verify the 2D modelling results. Analysing and predicting the parameters helps to reduce the number of trial-and-error processes in experiments, and we expect this work to provide a theoretical parametric basis for micro-hemispherical shell machining.
Corrigendum: Dynamic Hubbard model: kinetic energy driven charge expulsion, charge inhomogeneity, hole superconductivity, and Meissner effect (2013 Phys. Scr.
88 035704)
Authors: Hirsch J E
Published: April 2024

The paper erroneously stated that inflowing electrons in the Meissner effect transmit momentum to the body through collisions.
Experimental study of hydraulic lifting platform based on multi-ring disc magnetorheological valve
Authors: Cao Zhiqiang , Xie Guojin , Huang Yinyan , Han Leigang , Yang Xiaolong
Published: April 2024

To enhance the operational capabilities of a hydraulic lifting apparatus, a hydraulic lifting platform was engineered based on a multi-ring disc magnetorheological valve. The pressure drop characteristics of the multi-ring disc magnetorheological valve were determined through theoretical analysis, supplemented by magnetic field simulations to assess its performance. The effects of different currents on the stability and response time of the hydraulic lifting platform are studied, and the control accuracy of the hydraulic lifting platform position is verified. The results show that the saturation current of the magnetorheological valve is 2.5 A. The addition of current to the magnetorheological valve leads to a rapid increase in both actuator speed and acceleration, which then levels off. Similarly, the response time of the actuator decreases with an increasing current until it stabilizes. At a coil current of 1.5 A, the actuator achieves a speed of approximately 86 mm s−1, an acceleration of approximately 105 mm s−2, and a response time of approximately 7.15 s. Furthermore, the lifting position accuracy of the hydraulic lifting platform is ±1 mm.
Insights into optoelectronic, thermodynamic, and thermoelectric properties of novel GePtCh (Ch = S, Se, Te) semiconductors: first-principles perspective
Authors: Salman Khan Muhammad , Gul Banat , Benabdellah Ghlamallah , Ahmad Bashir , Alotaibi Nouf H , Mohammad Saikh , Ahmad Hijaz
Published: April 2024

Ternary chalcogenides are often studied for their remarkable heat resistance and flexible optical properties. We used density functional theory and examine complicated connections between the various physical features of the exclusive GePtCh (Ch = S, Se, and Te) ternary chalcogenides. The valence band is formed by the hybridization of the Ge-s/p/d, Pt-s/p/d, S-p, Se-p, and Te-p orbitals in the energy range of −6.0 eV to 0 eV. The materials under consideration are confirmed as indirect bandgap materials with estimated energy gaps of 1.29 eV, 0.86 eV, and 0.48 eV, respectively. By substituting Se and Te for S reduced the bandgap in these materials. The complex dielectric function’s components, absorption coefficients, real optical conductivity, energy loss functions, refractive index, reflectivity, and extinction coefficient, are studied and examined to identify their potential use in optoelectronic applications. The thermodynamic parameters of these ternary systems are calculated by employing the quasi-harmonic Debye model. The materials are suitable for thermoelectric devices, as evidenced by their considerable and outstanding thermoelectric features. The GePtTe possessed the highest absorption, indicating that it is a suitable material for the use in optoelectronic applications.
Slots and stubs incorporated annular ring-shaped compact microstrip antenna with circular polarization characteristics for wireless UWB communication systems
Authors: El-Arrouch Tarik , Das Sudipta , Islam Tanvir , Sorathiya Vishal , Madhav Boddapati Taraka Phani , El Ansari Abdelaaziz , El Amrani El Idrissi Najiba
Published: April 2024

A circularly polarized (CP) antenna with ultra-wideband resonance and a broad axial ratio bandwidth is designed for UWB communication systems. The prescribed design comprises of a modified annular ring-shaped radiator and a modified step-graded slots loaded partial ground plane. The projected antenna is prototyped on FR4 substrate of 35 × 30 × 1.6 mm3. To achieve wide axial ratio bandwidth, a rectangular vertical slot is inserted into the radiating patch and two stubs are embedded into the monopole ground plane, which is configured with step graded rectangular slots. The simulation results are verified by testing the fabricated protype. The proposed design operates at UWB spectrum with an ultra-wide impedance bandwidth (IBW) of 134.57%, centered at 10.7 GHz, covering 3.5 GHz to 17.9 GHz frequency spectrum. Furthermore, it demonstrates circular polarization characteristics with a broad axial ratio bandwidth (ARBW) of 96.29% expanding from 3.5–10 GHz (6500 MHz). Its peak gain reaches to 8.7 dBi and a maximum radiation efficiency of 95% is achieved within the operating band. The results (measured and simulated) obtained in terms of S11, axial ratio, gain and efficiency and radiation patterns exhibit high agreement. The presented antenna could be a suitable choice for 5.5 GHz Worldwide Interoperability for Microwave Access (Wi-Max), 5.2/5.8 GHz Wireless local area network (WLAN), X-band satellite communication (downlink: 7.25–7.745 GHz, uplink: 7.9–8.4 GHz), UWB communication systems, and other applications in microwave C, X, Ku bands due to its superior characteristics.
Optimizing the noise control in a two-layer conduit
Authors: Shafique Sajid , Arsalan Ahmad Muhammad , Afzal Muhammad
Published: April 2024

In the modern world, noise pollution is a major concern due to its prevalence. This work focuses on optimizing noise control in a two-layer conduit. A conduit comprises an inlet and double-outlet zones (DOZ). The upper walls of the DOZ are lined with perforated absorbent material while the lower walls are layered with fibrous. Mathematically, the physical problem is formulated with a field wave equation together with rigid and impedance boundary conditions in the respective zones. Such governing boundary value problem (BVP) leads to the Sturm-Liouville (SL) category in which standard orthogonality relations (OR) are indispensable. The system of the linear equations of the BVP is acquired with semi-analytical Mode-Matching (MM) approach by implementing the continuity conditions of sound pressures and velocities at the matching junction with the aid of OR. These systems are truncated and solved numerically with computation learning to obtain the reflected and transmitted modal amplitudes in respective zones. Due to the lining's perforated upper walls, fibrous lower walls, and reversal in the DOZ, the analysis of the reflected and transmitted powers versus frequencies is significantly observed and is shown in graphical findings. The algebraic derivation is validated by satisfying the conservation law of power flux and matching continuity conditions for impedance, perforated, and fibrous lined boundaries.
A multi-mode free-space delay interferometer with no refractive compensation elements for phase-encoded QKD protocols
Authors: Tretiakov V V , Kravtsov K S , Klimov A N , Kulik S P
Published: April 2024

We demonstrate a compensation-free approach to the realization of multi-mode delay interferometers, mainly for use in phase-encoded quantum key distribution (QKD). High interference visibility of spatially multi-mode beams in unbalanced Michelson or Mach–Zehnder interferometers with a relatively wide range of delays is achieved by the appropriate choice of the transverse size of the beam. We provide a simple theoretical model that gives a direct connection between the visibility of interference, the delay and the beam parameters. The performed experimental study confirms our theoretical findings and demonstrates measured visibility of up to 0.95 for a delay of 2 ns. Our approach’s simplicity and robust performance make it a practical choice for the implementation of QKD systems, where a quantum signal is received over a multi-mode fiber. The important application of such a configuration is an intermodal QKD system, where the free-space atmospheric communication channel is coupled into a span of the multi-mode fiber, delivering the spatially distorted beam to the remote receiver with minimal coupling loss.
Large dynamic range digital delay with sub-picosecond precision
Authors: Dehmeshki Diba , Eberle Zachariah , Frahm Erich , Rusack Roger , Saradhy Rohith , Tousi Yahya
Published: April 2024

We report on the development and performance of a digitally controlled phase delay with a step of 280 femtoseconds and a dynamic range of 230 picoseconds. Details of the device design and the simulations as well as comparisons with laboratory measurements will be discussed. We describe how we have used this ASIC to stabilize a digital clock to a precision of less than one picosecond.
Construction and evaluation of a large radiation detector for Positron Emission Tomography applications
Authors: Raylman R.R. , Stolin A.V. , Jaliparthi G. , Martone P.F.
Published: April 2024

Large arrays of pixelated scintillator potentially have
application in economical construction of PET scanners. In this
investigation, we constructed and evaluated a detector with an
active area of 32.26 × 13.47 cm2. It is based on a
218 × 91 array of 1.4 × 1.4 × 15 mm3 LYSO
elements (pitch 1.48 mm). Scintillation light is detected with a
5 × 12 array of silicon photomultipliers (SiPM) arrays. Each
array consists of an 8 × 8 array of 3 × 3 mm2 
(pitch 3.35 mm) SiPMs. Performance of these devices are enhanced
and stabilized by cooling them. Testing revealed that the detector
was able to detect 90% of the theoretically detectable 511 keV
photons. The resolvability index (a measure of the ability to
identify individual detector elements from background) is
0.24 ± 0.04. Additionally, the average energy resolution for the
complete detector is 18.3%. These results compare well with those
reported for much smaller detector modules.
Charge amplification in sub-atmospheric CF4:He mixtures for directional dark matter searches
Authors: McLean A.G. , Spooner N.J.C. , Crane T. , Eldridge C. , Ezeribe A.C. , Marcelo Gregorio R.R. , Scarff A.
Published: April 2024

Low pressure gaseous Time Projection Chambers (TPCs) are a
viable technology for directional Dark Matter (DM) searches and have
the potential for exploring the parameter space below the neutrino
fog [1,2]. Gases like CF4 are advantageous
because they contain flourine which is predicted to have heightened
elastic scattering rates with a possible Weakly Interacting Massive
Particle (WIMP) DM candidate [3,4,5]. The
low pressure of CF4 must be maintained, ideally lower than
100 Torr, in order to elongate potential Nuclear Recoil (NR) tracks
which allows for improved directional sensitivity and NR/Electron
Recoil (ER) discrimination [6]. Recent evidence suggests
that He can be added to heavier gases, like CF4, without
significantly affecting the length of 12C and 19F recoils
due to its lower mass. Such addition of He has the advantage of
improving sensitivity to lower mass
WIMPs [1]. Simulations can not reliably predict
operational stability in these low pressure gas mixtures and thus
must be demonstrated experimentally. In this paper we investigate
how the addition of He to low pressure CF4 affects the gas gain
and energy resolution achieved with a single Thick Gaseous Electron
Multiplier (ThGEM).
Antiproliferative efficacy and mechanism of action of garlic phytochemicals-functionalized gold nanoparticles in triple-negative breast cancer cells
Authors: Meher Kimaya , Paithankar Harshad , Hosur Ramakrishna V , Lopus Manu
Published: April 2024

Fabrication of gold nanoparticles (GNPs) with phytochemicals is an emerging green nanotechnology approach with therapeutic implications. Garlic, known for its culinary and medicinal properties, has been extensively investigated for its anticancer properties. Here, we report a method to substantially enhance the antiproliferative potency of garlic by functionalizing its phytochemicals to GNPs and demonstrate a possible mechanism of action of these nanoparticles in the triple-negative breast cancer cell line, MDA-MB-231. Garlic gold nanoparticles (As-GNPs) were synthesized using garlic extract (As-EX) and gold chloride and characterized using a variety of spectroscopy techniques, and transmission electron microscopy (TEM). Compared to As-EX, which has a negligible effect on the viability of the cells, As-GNPs inhibited cell viability with an IC50 of 0.310 ± 0.04 mg ml−1 and strongly inhibited the clonogenic and migratory propensities of these cells. As indicated by TEM, the As-GNPs entered the cells via endocytosis and dispersed in the cellular milieu. Since tubulin, the protein involved in cell division, is a verified target for several antiproliferative drugs, we next examined whether the As-GNPs interact with this protein. The As-GNPs showed concentration-dependent binding to purified tubulin, slightly but consistently perturbing its secondary helical integritywithout grossly damaging the tertiary structure of the protein or the net polymer mass of the microtubules, as indicated by a tryptophan-quenching assay, far UV-circular dichroism spectroscopy, anilinonaphthalene sulfonate-binding assay, and polymer mass analysis, respectively. In cells, As-GNPs killed the cancer cells without cell cycle arrest, as evidenced by flow cytometry.
Escalating rainstorm-induced flood risks in the Yellow River Basin, China
Authors: Hu Lei , Zhang Qiang , Singh Vijay P , Wang Gang , He Changyuan , Zhao Jiaqi
Published: April 2024

The warming climate-induced intensification of hydrological cycle is amplifying extreme precipitation and increasing flood risk at regional and global scales. The evaluation of flood risk, which depends on assessment indicators, weights, as well as data quality, is the first step toward mitigation flood disasters. In this study, we accepted ten risk assessment indicators concerning hazard of disaster-causing factors, sensitivity of hazard-forming environments, and vulnerability of disaster-bearing bodies. We used a combined weighting method based on the analytic hierarchy process and entropy weight (AHP-EW) technique to evaluate rainstorm-induced flood risks across the Yellow River Basin (YRB) from 2000 to 2018. We observed flood hazards are intensifying across the YRB. Specifically, areas with medium flood hazards expanded from the lower to the middle and upper YRB. The sensitivity to floods exhibited a spatial pattern of increasing from southeast to northwest (lower to upper YRB). The increase in vegetation coverage in the middle and upper reaches of the YRB reduces the sensitivity to flood disasters. Flood vulnerability shows an increasing trend, with higher vulnerability mainly observed in the middle and lower YRB. The overall flood risk in the YRB shows an increasing trend, with a 9-fold increase in flood risk from 2000 to 2018. Medium to high flood risk and vulnerability can mainly be identified in the middle and lower YRB, where population and gross domestic product are concentrated. The intensifying rainstorm-induced flood risks over urban areas in these regions should arouse public concern.
Mapping drivers of tropical forest loss with satellite image time series and machine learning
Authors: Pišl Jan , Rußwurm Marc , Haydn Hughes Lloyd , Lenczner Gaston , See Linda , Dirk Wegner Jan , Tuia Devis
Published: April 2024

The rates of tropical deforestation remain high, resulting in carbon emissions, biodiversity loss, and impacts on local communities. To design effective policies to tackle this, it is necessary to know what the drivers behind deforestation are. Since drivers vary in space and time, producing accurate spatially explicit maps with regular temporal updates is essential. Drivers can be recognized from satellite imagery but the scale of tropical deforestation makes it unfeasible to do so manually. Machine learning opens up possibilities for automating and scaling up this process. In this study, we developed and trained a deep learning model to classify the drivers of any forest loss—including deforestation—from satellite image time series. Our model architecture allows understanding of how the input time series is used to make a prediction, showing the model learns different patterns for recognizing each driver and highlighting the need for temporal data. We used our model to classify over

588

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sites to produce a map detailing the drivers behind tropical forest loss. The results confirm that the majority of it is driven by agriculture, but also show significant regional differences. Such data is a crucial source of information to enable targeting specific drivers locally and can be updated in the future using free satellite data.
Fabrication of Superhydrophobic (TiO2/PDMS) Coating For Oil-Water Separation
Authors: Majeed Ali N. , Sabry Raad S. , Abid Muslim.A.
Published: April 2024

Oil-contaminated water as a result of oil spill disasters or industrial disposal is a threat to human health and environmental sustainability on a global scale. The rising need for efficient oil-water separation has led to a growing interest in superhydrophobic materials for this purpose. Due to the regeneration ability of nanoparticles of titanium dioxide (TiO2), superhydrophobic and superolephilic TiO2/PDMS were created using a simple, low cost dip coating procedure. TiO2 (NPs) was synthesised by hydrothermal method and modified with PDMS (FS-1200 silicon sealant) solution. The mesh coated had remarkable superhydrophobicity, as seen by a contact angle of 155° with water. Additionally, the surface displayed superoleophilicity, as indicated by an oil contact angle (OCA) of 0°. The coated mesh surface was characterized by X-ray diffraction analysis, contact angle measurement, field emissions scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), and energy dispersive spectroscopy (EDS). The separation of kerosene-water, diesel oil-water combinations, and sunflower oil-water may be effectively achieved via a simple filtering approach using a coated mesh. This method demonstrates a notable separation efficiency of 91.6%.