bluuebunny/crossref_metadata_2025 huggingface dataset:
Onset of cabbeling instabilities in superconfined two-fluid systems
Authors: Leyrer J. , Ulloa H. N. , Ortega J. H. , Letelier J. A.
Published: December 2024

Convective-driven mixing in permeable subsurface environments is relevant in engineering and natural systems. This process occurs in groundwater remediation, oil recovery, CO2 sequestration, and hydrothermal environments. When two fluids come into contact in superconfined geometries like open fractures in rocks, complex molecular dynamics can develop at the fluid–fluid interface, creating a denser mixture and leading to cabbeling instabilities that propel solutal convection. Previous studies in superconfined systems have used models based on unstable density distributions—generating Rayleigh–Taylor instabilities—and analog fluid mixtures characterized by nonlinear equations of state—resulting in cabbeling dynamics—yet often neglecting interfacial tension effects, which is also relevant in miscible systems. This study incorporates the Korteweg tensor into the Hele–Shaw model to better understand the combined influence of geometry confinement and interfacial tension on the onset of cabbeling instabilities in two-fluid superconfined systems. Through direct numerical simulations, we investigate the system's stability, revealing that the onset, characterized by the critical time tc, exhibits a nonlinear relationship with the system's nondimensional parameters—the Rayleigh number Ra, the anisotropy ratio ϵ, and the Korteweg number Ko. This relationship is crystallized into a single scaling law tc=F(Ra,ϵ,Ko). Our findings indicate that geometry and effective interfacial tension exert a stabilizing effect during the initial stages of convection, stressing the necessity for further exploration of its influence on fluid mixing in superconfined systems.
Frequency-shifted f-2f interferometer for unveiling the noise performance of carrier-envelope offset in passively stabilized frequency combs
Authors: Tian Haochen , Cai Yu , Yang Tao , Wang Qiang , Wang Xinqi , Lin Baike , Meng Fei , Li Ye , Fang Zhanjun , Steinmeyer Günter , Lin Yige
Published: December 2024

The past two decades have seen rapid development of optical atomic clocks with fractional performance at 10−18 level or even below. Dissemination of optical atomic clocks into microwave domain and their intercomparisons using optical frequency combs as clockwork requires precise measurements of their carrier-envelope offset frequencies (fceo). To this end, passive stabilization to zero offset frequency has been considered as a promising approach. However, previous studies often indicate imperfections in passive stabilization schemes. Therefore, in this Letter, aiming to unveil the in-depth noise performance and origin of fceo of passively stabilized frequency combs, a frequency-shifted f-2f interferometer is presented to characterize the fceo frequency stability, frequency shift, frequency uncertainty, linewidth, and phase noise. The stability observed amounts to 2.46 × 10−17 and 4.05 × 10−20 in 1 and 10 000 s, respectively. The linewidth of fceo is 3.7 mHz, with resulting phase noise of − 40 dBrad2/Hz and −64 dBrad2/Hz at 1 and 10 Hz offset frequency, respectively. The phase noise at > 1 kHz is confirmed to be of stochastic origin through correlation analysis. The measured fceo is conclusively determined as −75(14) μHz.
Mapping the dynamics of energy relaxation in exciton–polaritons using ultrafast two-dimensional electronic spectroscopy
Authors: Dhamija Shaina , Son Minjung
Published: December 2024

Exciton–polaritons are quasiparticles that are formed by strong interactions between light and electronic transitions of matter. Polariton states exhibit the characteristics of both photons and the matter transitions, which leads to photophysical and chemical properties distinct from those observed in pure matter states, such as enhanced energy transport and altered chemical reactivity and conductivity. Critical to understanding how these exciting phenomena are enabled is understanding the underlying photophysical mechanisms of the interactions between polaritonic states and the associated energy relaxation pathways. Ultrafast spectroscopic techniques, such as transient absorption spectroscopy, have been increasingly utilized to interrogate the rapid relaxation dynamics of these partly light-like, short-lived states, albeit with limitations and ambiguities. In this review, we discuss how two-dimensional electronic spectroscopy, an ultrafast technique that has been underemployed in the studies of exciton–polaritons thus far, can offer detailed insights into the primary photophysical events of energy relaxation in exciton–polaritons that are not accessible in transient absorption, through the analysis of off-diagonal cross peaks and line shapes.
Computational investigation of the dynamics of the constituents in a glucose-based biodegradable deep eutectic solvent
Authors: Sarkar Soham , Müller-Plathe Florian
Published: December 2024

Atomistically detailed force field is employed to investigate the dynamics of a naturally abundant deep eutectic solvent at 328 K, composed of glucose, urea, and water in a 6:4:1 mass ratio. This study examines key dynamical processes, including translational motion, molecular reorientation, and hydrogen bond relaxation, with timescales ranging from a few picoseconds to a few nanoseconds. Characteristic times associated with the translational and the rotational motion increase with molecular size, i.e., water being the fastest and glucose the slowest. Jump length analysis shows that urea and glucose traverse fractions of their molecular diameters during jumps, suggesting gliding motion. We find that water molecules exhibit strong anisotropic reorientation, which is moderate for urea and nearly absent in the case of glucose molecules. Correlation analysis of analogous transport quantities among the constituents reveals that reorientation of the dipole axis is less coupled to the translational diffusion compared to the reorientation around the dipolar axis. Finally, we observe that hydrogen bond relaxation times for water and urea are highly dependent on the number of hydrogen bonds formed, while for glucose, the slower molecular motion influences its hydrogen-bond relaxation.
Transparent glass force plate with CrN strain gauges featuring a notch structure
Authors: Oda Ryo , Okamoto Yuki , Nakashima Rihachiro , Takei Yusuke , Takahashi Hidetoshi
Published: December 2024

Microforce plate is a powerful tool as force sensors in the field of microelectromechanical systems (MEMS). These force plates can be used to quantitatively measure the minute insects’ ground reaction forces and microdroplets’ collision forces. During such measurements, there is often a demand specification for observing the interface between the object and the plate from the backside. However, transparent materials were not compatible with traditional MEMS force plate fabrication processes. Here, we propose a fabrication process for a transparent glass force plate by forming a notch structure on a glass substrate using chromium nitride (CrN) as a strain gauge. The force plate was designed as a 10 × 10 × 0.1 mm plate supported by beams on all four sides. The plate shape and groove formation were easily realized by applying a laser machining process to glass cutting. The force applied to the plate was measured using CrN strain gauges placed on a support beam. The fabricated force plate achieved a force resolution of less than 1 mN in the range of 100 mN. Additionally, the positional error across the entire plate was approximately ±10%. The proposed glass force plate is expected to be utilized in small-force measurements such as droplet collision observations, which require transparent plates for optical observation.
A flexible lightweight graphene-based all-dielectric metamaterial for broadband microwave absorption
Authors: Zhuang Haiyan , Guo Mengchao , Wang Jingjing , Wang Xiaokun , Wang Jiafu , Qu Shaobo , Tang Dongming , Zhang Baoshan , Yang Yi
Published: December 2024

To meet the demanding requirements of practical microwave absorbers, such as broadband absorption, considerations must encompass thickness, flexibility, surface density, and manufacturing feasibility. However, absorbers that effectively address all of these aspects are currently scarce. This study introduces a novel graphene-based all-dielectric metamaterial absorber (ADMMA) featuring a trap-like structure, inspired by impedance alternation strategy. Leveraging the dielectric dispersion properties of graphene composites, this ADMMA strategically manipulates the effects of Spoof Surface Plasmon Polaritons, standing wave resonance and half-wave dipole resonance, allocating them to distinct frequency bands, thus achieving a thin-layer broadband absorber. Simulation results demonstrate that, under vertical incidence, the ADMMA achieves a −10 dB bandwidth from 8.1 to 23.1 GHz. A 3 mm-thick sample, with a surface density of merely 2.85 Kg m−2, is fabricated using a straightforward process, and reflectance test results closely align with simulation outcomes. Furthermore, it exhibits robust stability under oblique incidences for both TE and TM modes. This innovative approach effectively reduces surface density without compromising absorption performances, emphasizing the potential of the ADMMA for practical applications.
Characterisation and potential control of reactive species formation during cold atmospheric plasma medium activation
Authors: Moreau Maxime , Ghzaiel Imen , Perisse Frédéric , Sleiman Mohamad , Sarakha Mohamed , Charlet Karine , Menecier Sébastien
Published: December 2024

Cold atmospheric plasma (CAP) has been studied for years in the context of cancer therapy, where it is efficient at inducing cell death. Reactive oxygen and nitrogen species (RONS), via oxidative stress, are reported to be responsible for the treatment effect, but the biological mechanisms involved are not fully understood. Cold plasma is very effective at producing RONS, but with very complex chemical kinetics, so in this study we propose to measure the concentrations of some species formed in the gas and aqueous phases to help understand the chemical interactions that could lead to an increase in the cancer treatment efficiency of cold plasma. An anticancer effect after exposure to CAP has been demonstrated on a prostate tumour cell line with both direct and indirect treatment. To determine RONS concentrations in both the gas and liquid phases, an experimental reactor was developed to allow different methods of analysis to be conducted in similar conditions and potentially simultaneously. In the gas phase, ozone and nitrogen oxides were evaluated and the influence of some physical parameters on their concentrations demonstrated using design of experiments. Nitrates, hydrogen peroxide, hydroxyl radicals and singlet oxygen have been produced in pure water, but in culture medium a significant concentration has only been measured for hydrogen peroxide. The components of culture medium appeared to scavenge the most reactive species. Future investigations will look at other key species, the influence of physical parameters on production of RONS in the liquid phase and also adjustment of the medium composition to prevent scavenging.
Continuous prediction of multi-joint angles based on Informer model using novel fused features
Authors: Wan Renyu , Zhu Zina , Cui Guohua , Chen Saixuan
Published: December 2024

Continuous prediction of multi-joint angles based on surface electromyography (sEMG) has the potential to enhance the human-machine interaction performance. However, achieving accurate angle prediction remains a significant challenge during various motions. In this study, a method for extracting gait feature, named Gait-Time, is proposed, and different models for predicting multi-joint angles are established and compared, including Informer, gated recurrent unit, one-dimensional convolutional neural network, long short term memory (LSTM), as well as two hybrid models, LSTM-BP and LSTM-Attention. The results indicate that Informer model, utilizing left lower limb sEMG fused with Gait-Time features as input, outperforms the other mentioned models, demonstrating promising outcomes with the average correlation coefficient values exceeding 0.99 for all three joints. Furthermore, the mean absolute error (MAE) and root mean square error (RMSE) for the ankle and hip joints average below 1°, while for the knee joint, both the average MAE and RMSE fell within a range of 2°. It can be concluded that the accuracy of Informer model is adequate to support the continuous prediction of multi-joint angles in human motion scenarios.
Process planning of repairing and grinding for cylindrical parts based on surface defect detection
Authors: Yu Zichao , Fan Diqing , Sha Ling , Liu Xintian , Dai Yuxuan
Published: December 2024

To realize the purpose of grinding and repairing surface defects in cylindrical parts, machine vision inspection technology and automatic grinding technology are integrated in this study. These technologies are combined to detect and repair defects in cylindrical parts using an automatic grinding and repair platform. For various defect types, the dynamic threshold extraction method is used, combined with the image difference method in the spatial and frequency domains through defect screening, sensor calibration and sub-pixel edge detection. The defect features are completely extracted and the defect size is determined to guide the polishing and repair platform to repair the surface defects of parts. A grinding path planning algorithm is proposed to solve the problem of the initial installation eccentricity of the workpiece, which can adjust the grinding wheel feed and grinding position. Finally, the experimental tests show that the designed automatic grinding repair system detects all defects without omission, and the average surface roughness of the cylindrical parts Ra is 3.17 μm after repair and polishing, which meets the grinding quality requirements.
MFD-UNet: a complex railway track boundary segmentation algorithm for drone vision based on multi-scale fusion and deformable pyramid blocks
Authors: Weng Yanbin , Xiang Hui , Chen Xiahu , Zhang Changfan , Jia Lin , Chen Fukang
Published: December 2024

Segmenting railway tracks from aerial imagery is critical in producing electronic railway maps. To address the challenges of railway track extraction from complex aerial imagery, this paper proposes an algorithm for complex railway track boundary segmentation Algorithm from complex aerial imagery based on MFD-UNet (Multi-scale attention Fusion and Deformable pyramid UNet). Firstly, we proposed a parallel deformable convolutional pyramid residual downsampling module. This module integrates deformable convolution with fixed convolution, dynamically adjusting the receptive field by learning offset values, and enhances the extraction of information at different scales by refining the residual blocks based on a pyramid structure. Secondly, a multi-scale attention fusion module is proposed in the skip connection part to integrate adjacent feature layers and reduce semantic differences. Additionally, a multi-layer optimized cross-entropy loss function is integrated into the decoder to enhance the model’s perception of information at various scales. Experimental results show that our algorithm can effectively segment railway tracks on both our self-built railway dataset and the Deep Globe dataset. Compared to the benchmark model, it has improved by 3.19% and 4.51% respectively, and the accuracy has also increased by 2.38% and 2.95%, achieving a good visual effect.
Evaluating the students’ learning on the electricity and magnetism using a conceptual survey BEMA
Authors: Koca Nazife Ozdes , Al Saqri Noor alhuda , Al Hamrashdi Hajir , Kindi Noor Al
Published: December 2024

In this work we evaluated the performance of first-year students of the College of Science and the College of Engineering at Sultan Qaboos University (SQU), Oman on the concepts of electricity and magnetism using the Brief Electricity and Magnetism Assessment (BEMA). The BEMA pre-test and post-test were implemented at the beginning of semester and toward the end of the semester respectively. We investigated the correlation between pre-test and post-test BEMA scores to offer a deeper insight into the students’ understanding of concepts. This study also examined the gain in individual subtopics and compared the BEMA results with the students’ final course grades. The findings indicate that students perform better on questions related to electostatics, struggle more with those related to magnetostatic and have significant difficulties with Faraday’s law. Additionally, a gender-based analysis was conducted, revealing no statistical difference in performance between male and female students.
Experimental measurement of mean transition path velocities of colloidal particles surmounting energy barriers
Authors: Ferrer Brandon R , Gomez-Solano Juan Ruben
Published: December 2024

Transition paths are rare events occurring when a system, thanks to the effect of fluctuations, crosses successfully from one stable state to another by surmounting an energy barrier. Even though they are of great significance in many mesoscale processes, their direct determination is often challenging due to their short duration as compared to other relevant time-scales of the system. Here, we measure the local average velocity along one-dimensional transition paths of a colloidal bead embedded in a glycerol/water mixture that hops over a barrier separating two optical potential wells. Owing to the slow dynamics of the bead in this viscous medium, we can spatially resolve the mean velocity profiles of the transition paths for distinct potentials, which agree with theoretical predictions of a one-dimensional model for the motion of a Brownian particle traversing a parabolic barrier. This allows us to experimentally verify various expressions linking the behavior of such mean velocities with equilibrium and transition path position distributions, mean transition-path times and mean escape times from the wells. We also show that artifacts in the mean velocity profiles arise when reducing the experimental time resolution, thus highlighting the importance of the sampling rate in the characterization of the transition path dynamics. Our results confirm that the mean transition path velocity establishes a fundamental relationship between mean transition path times and equilibrium rates in thermally activated processes of small-scaled systems.
A 400 Gbit Ethernet Core Enabling High Data Rate Streaming from FPGAs to Servers and GPUs in Radio Astronomy
Authors: Liu Wei , Burnett Mitchell C. , Werthimer Dan , Kocz Jonathon
Published: December 2024

The increased bandwidth coupled with the large numbers of antennas of several new radio telescope arrays has resulted in an exponential increase in the amount of data that needs to be recorded and processed. In many cases, it is necessary to process this data in real time, as the raw data volumes are too high to be recorded and stored. Due to the ability of GPUs to process data in parallel, GPUs are increasingly used for data-intensive tasks. In most radio astronomy digital instrumentation (e.g., correlators for spectral imaging, beamforming, pulsar, fast radio burst and SETI searching), the processing power of modern GPUs is limited by the input/output data rate, not by the GPU's computation ability. Techniques for streaming ultra-high-rate data to GPUs, such as those described in this paper, reduce the number of GPUs and servers needed, and make significant reductions in the cost, power consumption, size, and complexity of GPU based radio astronomy backends. In this research, we developed and tested several different techniques to stream data from network interface cards (NICs) to GPUs. We also developed an open-source UDP/IPv4 400 GbE wrapper for the AMD/Xilinx IP demonstrating high-speed data stream transfer from a field programmable gate array (FPGA) to GPU.
Research on hidden methods for sensitive targets in remote sensing images
Authors: Tang Maolin , Hou Xiang , Zhang Xueyang
Published: December 2024

A digital watermarking hiding and restoration algorithm based on discrete wavelet transform is proposed to solve the problem of needing to hide some sensitive targets in remote sensing images from unauthorized users and restore them for authorized users. First, the sensitive target areas in the original remote sensing image are segmented and extracted. Then, based on the texture features of the surrounding area of the segmented region, a grayscale filling operation is performed on the blank area left after extraction, thus generating a pseudo-carrier image. The extracted sensitive target image is then embedded as a watermark into the low-frequency region of the pseudo-carrier image, generating a pseudo-carrier image that hides the sensitive target. The extraction of the sensitive target does not require the original image information, achieving blind extraction. The transparency after watermark embedding is shown to be good by the algorithm. It is also demonstrated that the algorithm possesses robustness against some conventional attacks.
Design of single-phase shifted full-bridge inverter voltage regulation system based on voltage-controlled closed-loop control and LLC resonant network
Authors: Wu Xueying , Wang Haisheng , Li He , Lv Chaoyuan , Feng Qichang
Published: December 2024

The phase-shifted full-bridge inverter is widely used in the field of power electronics technology, aiming to achieve precise regulation of the output voltage and improve the stability and efficiency of the power system. This paper proposes a single-phase phase-shift full-bridge inverter voltage regulation system and its parameter design method based on the LLC resonant network. Combined with voltage-controlled closed-loop control and APFC technology, the working mode of the system circuit is analyzed, and the system parameters are designed. The system simulation model is built in MATLAB/Simulink. The constant voltage output of the system is realized, the power factor is greater than 96%, and the relative error of the output voltage change is less than 2%.
Single-pixel orbital angular momentum detection in the temporal domain
Authors: Badavath Purnesh Singh , Kumar Vijay
Published: December 2024

Orbital angular momentum (OAM) beam’s spatial information captured using a camera, employs millions of single-pixel detectors arranged in a two-dimensional matrix. Poses challenges in OAM detection due to significant storage requirements, reduced speed due to low frame rate, and increased post-processing time. To address this bottleneck, a novel OAM detection technique utilizing only a diffuser and a single-pixel fast photodiode (FPD) is reported. The sixteen OAM beams,

l
=

[

−
8
+
8

]

interact with the rotating diffuser resulting in a temporally varying speckle field. The 1D temporal speckle information (TSI) has been segregated from the temporally varying 2D speckle pattern images for each beam. The segregated 1D TSI has been classified by employing a machine learning model and achieved a classification accuracy of 97.1% and 97.3% on simulated and experimental data respectively. To further validate the proposed single-pixel OAM detection method, the 1D TSI is captured directly using a FPD. The experimentally captured 1D TSI captured via photodiode has been classified by a lightweight custom-designed 1D convolutional neural network and achieved an increased classification accuracy of 96%. This approach redefines OAM detection, operating in the temporal domain with a single-pixel FPD, thereby significantly reducing storage and computational costs while promising high-speed OAM detection.
Thermoelectric performance enhancement of Mg2Si-based silicides synthesized in nitrogen atmosphere
Authors: Solco Samantha Faye Duran , Saglik Kivanc , Zhang Danwei , Tan Xian Yi , Zhu Qiang , Liu Hongfei , Suwardi Ady , Cao Jing
Published: December 2024

In this work, we compare the thermoelectric performance of Mg2Si-based compounds by synthesizing them in N2 compared to Ar atmosphere during ball milling. In addition, we achieved high thermoelectric performance by introducing Sn-alloying as well as Zn- and Bi-co doping. The high performance originated from simultaneous improvement in electrical conductivity and reduced thermal conductivity. This results in peak zT near 1.0 at 760 K for Mg1.9925Zn0.0075Si0.48Sn0.5Bi0.02. Owing to the much lower cost (higher abundance) of N2 compared to Ar owing to their much higher relative abundance, such processing strategy is expected to improve sustainability. Furthermore, the insights derived from this work can potentially be applied to other compounds containing Mg- and other reactive elements. Fundamentally, this result will also motivate further studies on the intrinsic defect formation in N2 vs Ar atmosphere, which affects both electronic and thermal transports.
Enhancing orthopedic infection control: carbon scaffold-mediated phage therapy for methicillin-resistant staphylococcus aureus in fracture-related infections
Authors: Arens Daniel K , Rodriguez Annette R , Huh Eun Y , Wang Heuy-Ching Hetty , Burdette Alexander J , Hwang Yoon Y
Published: December 2024

Fracture-related infections are burdensome conditions that affect both a patient’s health and financial well-being. Preventing an infection and stabilizing the fracture are critical aspects in a care plan that rely on antibiotics and orthopedic implants, both which need to be improved. Bacteriophage or phage are viruses that specifically kill bacteria and are a promising alternative/companion to antibiotics while enhanced orthopedic implants that are osteoinductive and biodegradable are needed for bone healing. In this work we report the inhibitory effectiveness of three phages Ø K, Ø 0146, and Ø 104023 alone and in combination against a strain of methicillin-resistant Staphylococcus aureus. Single phage and cocktails were mixed with bacteria at multiplicities of infection of 5 and 2.5 and growth was measured using optical density over 48 h. Ø K alone and Ø K + Ø 0146 were able to completely inhibit bacterial growth. We also present and the ability of Ø K to bind to and be released from a biodegradable and biocompatible orthopedic carbon scaffold. The carbon scaffold was soaked in a solution of Ø K, washed, and then incubated in sequential buffer baths while samples were removed at timepoints up to seven days to calculate phage elution. At every timepoint measured including seven days, phages were found to still be eluting from the scaffold. These results indicate that the studied phages are effective bacterial inhibitors and could be used to prevent infections. Furthermore, orthopedic implants such as a carbon scaffold can be coated with phage to provide long-term protection. In vivo infection experiments on phage loaded scaffold that test bacterial clearance, phage persistence in tissue, resolution of inflammation, and bone regrowth with an active infection are needed to further this work.
Non-conventional deep brain stimulation in a network model of movement disorders
Authors: Yousif Nada , Bain Peter G , Nandi Dipankar , Borisyuk Roman
Published: December 2024

Conventional deep brain stimulation (DBS) for movement disorders is a well-established clinical treatment. Over the last few decades, over 200,000 people have been treated by DBS worldwide for several neurological conditions, including Parkinson’s disease and Essential Tremor. DBS involves implanting electrodes into disorder-specific targets in the brain and applying an electric current. Although the hardware has developed in recent years, the clinically used stimulation pattern has remained as a regular frequency square pulse. Recent studies have suggested that phase-locking, coordinated reset or irregular patterns may be as or more effective at desynchronising the pathological neural activity. Such studies have shown efficacy using detailed neuron models or highly simplified networks and considered one frequency band. We previously described a population level model which generates oscillatory activity in both the beta band (20 Hz) and the tremor band (4 Hz). Here we use this model to look at the impact of applying regular, irregular and phase dependent bursts of stimulation, and show how this influences both tremor- and beta-band activity. We found that bursts are as or more effective at suppressing the pathological oscillations compared to continuous DBS. Importantly however, at higher amplitudes we found that the stimulus drove the network activity, as seen previously. Strikingly, this suppression was most apparent for the tremor band oscillations, with beta band pathological activity being more resistant to the burst stimulation compared to continuous, conventional DBS. Furthermore, our simulations showed that phase-locked bursts of stimulation did not convey much improvement on regular bursts of oscillation. Using a genetic algorithm optimisation approach to find the best stimulation parameters for regular, irregular and phase-locked bursts, we confirmed that tremor band oscillations could be more readily suppressed. Our results allow exploration of stimulation mechanisms at the network level to formulate testable predictions regarding parameter settings in DBS.
Development of a novel flexible bone drill integrating hydraulic pressure wave technology
Authors: de Kater Esther P , Kaptijn Tjalling G , Breedveld Paul , Sakes Aimée
Published: December 2024

Orthopedic surgery relies on bone drills to create tunnels for fracture fixation, bone fusion, or tendon repair. Traditional rigid and straight bone drills often pose challenges in accessing the desired entry points without risking damage to the surrounding anatomical structures, especially in minimal invasive procedures. In this study, we explore the use of hydraulic pressure waves in a flexible bone design to facilitate bone drilling. The HydroFlex Drill includes a handle for generating a hydraulic pressure wave in the flexible, fluid-filled shaft to transmit an impulse to the hammer tip, enabling bone drilling. We evaluated seven different hammer tip shapes to determine their impact on drilling efficiency. Subsequently, the most promising tip was implemented in the HydroFlex Drill. The HydroFlex Drill Validation demonstrated the drill’s ability to successfully transfer the impulse generated in the handle to the hammer tip, with the shaft in different curves. This combined with the drill’s ability to create indentations in bone phantom material is a promising first step towards the development of a flexible or even steerable bone drill. With ongoing research to enhance the drilling efficiency, the HydroFlex Drill opens possibilities for a range of orthopedic surgical procedures where minimally invasive drilling is essential.
European Space Agency launches Hera mission
Authors: Banks Michael
Published: December 2024

The European Space Agency (ESA) has launched a €360m mission to perform a close-up “crash-scene” investigation of the 150 m-diameter asteroid Dimorphos, which was purposely hit by a NASA probe in 2022.
Gassing around
Authors: Harris Margaret
Published: December 2024

Margaret Harris reviews It’s a Gas: the Magnificent and Elusive Elements that Expand Our World by Mark Miodownik.
Ask me anything: Fatima Gunning
Authors: Skipper Katherine
Published: December 2024

Fatima Gunning is a physicist at the Tyndall National Institute, a research flagship of University College Cork (UCC), Ireland, where she is also head of graduate studies, and education and public engagement (EPE). Gunning is also a principal investigator at IPIC, the Research Ireland Centre for photonics and a fellow in the schools of physics and engineering and architecture at UCC.
Local ergotropy and its fluctuations across a dissipative quantum phase transition
Authors: Di Bello G , Farina D , Jansen D , Perroni C A , Cataudella V , De Filippis G
Published: December 2024

We investigate a two-qubit open Rabi model, focusing on local ergotropy-the maximum extractable work by acting solely on the two qubits-within a parameter regime where a Berezinskii–Kosterlitz–Thouless dissipative phase transition occurs. First, we aim to define a protocol for charging, storing, and discharging the two-qubit subsystem, interpreted as the working principle of an open quantum battery. Second, we examine the impact of the phase transition on ergotropy and identify potential markers. To achieve these goals, we construct an ad-hoc charging unitary operator, leveraging our knowledge of the ground state near the transition to bring it into a decoherence-free state (DFS) during storage. Using state-of-the-art numerics based on matrix product state representation, we reveal that high couplings to an external bath approximately double the local ergotropy immediately post-charging. Over time we observe oscillatory behaviors in ergotropy and its fluctuations, which undergo significant changes near the transition, signaling its occurrence. Furthermore, we optimize local ergotropy over time using a physically inspired ansatz, enabling work extraction at a generic time (local ergotropy never reaches zero). Our work proposes a tunable, experimentally realizable protocol for work extraction, leveraging DFS and phase transitions. Additionally, it sheds light on the complex interaction between local ergotropy and quantum phase transitions.
Multi-modal deep learning architecture for enhanced feature extraction and classification of imagined speech words
Authors: Mohan Anand , Anand RS
Published: December 2024

Imagined speech prediction is a challenging task with significant implications for brain-computer interfaces (BCIs) and assistive communication technologies. EEG signals are highly non-stationary and thus it is extremely difficult to find any relevant information from these electroencephalogram (EEG) signals just by seeing them in time domain. Imagined speech-based BCIs can be integrated into assistive technology devices that are specifically designed for individuals with severe physical disabilities and can also play a role in rehabilitation programs for individuals recovering from conditions that affect speech and mobility. This paper proposes a novel hybrid model that combines convolutional neural network (CNN) and recurrent neural networks (RNNs) to predict imagined speech patterns from electroencephalography (EEG) signals. The integration of CNNs allows the model to capture spatial information from multi-channel EEG data, while RNNs excel at capturing temporal dependencies inherent in sequential EEG signals. The proposed model architecture starts with a 1-D CNN layer to extract spatial features from raw EEG data. The output is then fed into RNNs to capture temporal patterns and relationships over time. It achieved competitive accuracy, averaging approximately 85.25, 87.50, 81.58 and 93.92 percent for short words, long words, vowels and short-long words respectively.
The Inductive Blockwise Alperin Weight Condition for the Chevalley Groups 𝐹₄(𝑞)
Authors: An Jianbei , Hiss Gerhard , Lübeck Frank
Published: December 2024

We verify the inductive blockwise Alperin weight condition in odd characteristic 

ℓ
\ell

for the finite exceptional Chevalley groups

F
4

(
q
)

F_4(q)

for 

q
q

not divisible by 

ℓ
\ell

.
Drinfeld Modular Forms of Arbitrary Rank
Authors: Basson Dirk , Breuer Florian , Pink Richard
Published: December 2024

This monograph provides a foundation for the theory of Drinfeld modular forms of arbitrary rank 

r
r

and is subdivided into three chapters. In the first chapter, we develop the analytic theory. Most of the work goes into defining and studying the

u
u

-expansion of a weak Drinfeld modular form, whose coefficients are weak Drinfeld modular forms of rank

r
−
1

r-1

. Based on that we give a precise definition of when a weak Drinfeld modular form is holomorphic at infinity and thus a Drinfeld modular form in the proper sense.

In the second chapter, we compare the analytic theory with the algebraic one that was begun in a paper of the third author. For any arithmetic congruence subgroup and any integral weight we establish an isomorphism between the space of analytic modular forms with the space of algebraic modular forms defined in terms of the Satake compactification. From this we deduce the important result that this space is finite dimensional.

In the third chapter, we construct and study some examples of Drinfeld modular forms. In particular, we define Eisenstein series, as well as the action of Hecke operators upon them, coefficient forms and discriminant forms. In the special case

A
=

F

q

[
t
]

A=\mathbb {F}_q[t]

we show that all modular forms for

G
L

r

(
Γ
(
t
)
)

\mathrm {GL}_r(\Gamma (t))

are generated by certain weight one Eisenstein series, and all modular forms for

G
L

r

(
A
)

\mathrm {GL}_r(A)

and

S
L

r

(
A
)

\mathrm {SL}_r(A)

are generated by certain coefficient forms and discriminant forms. We also compute the dimensions of the spaces of such modular forms.
On the Problem of Infinite Spin in Total Collisions of the Planar 𝑁-Body Problem
Authors: Yu Xiang
Published: December 2024

For the planar

N
N

-body problem, we introduce a class of moving coordinates suitable for orbits near central configurations, especially for total collision orbits, which is the main new ingredient of this paper. The moving coordinates allow us to reduce the degeneracy of the

N
N

-Body problem from its intrinsic symmetrical characteristic. First, we give a full answer to the infinite spin or

P
a
i
n
l
e
v

e
´

Painlev\acute {e}

-

W
i
n
t
n
e
r

Wintner

problem in the case corresponding to nondegenerate central configurations. Then following some original ideas of C.L. Siegel, especially the idea of normal forms, and applying the theory of central manifolds, we give a partial answer to the problem in the case corresponding to degenerate central configurations. We completely answer the problem in the case corresponding to central configurations with degree of degeneracy one. Combining some results on the planar nonhyperbolic equilibrium point, we give a criterion in the case corresponding to central configurations with degree of degeneracy two. We further answer the problem in the case corresponding to all known central configurations of four bodies. Therefore, we solve the problem for almost every choice of the masses of the four-body problem. Finally, we give a measure of the set of initial conditions leading to total collisions.
Hamiltonicity of Random Subgraphs of the Hypercube
Authors: Condon Padraig , Espuny Díaz Alberto , Girão António , Kühn Daniela , Osthus Deryk
Published: December 2024

We study Hamiltonicity in random subgraphs of the hypercube

Q

n

\mathcal {Q}^n

. Our first main theorem is an optimal hitting time result. Consider the random process which includes the edges of

Q

n

\mathcal {Q}^n

according to a uniformly chosen random ordering. Then, with high probability, as soon as the graph produced by this process has minimum degree

2
k

2k

, it contains

k
k

edge-disjoint Hamilton cycles, for any fixed

k
∈

N

k\in \mathbb {N}

. Secondly, we obtain a perturbation result: if

H
⊆

Q

n

H\subseteq \mathcal {Q}^n

satisfies

δ
(
H
)
≥
α
n

\delta (H)\geq \alpha n

with

α
>
0

\alpha >0

fixed and we consider a random binomial subgraph

Q

p
n

\mathcal {Q}^n_p

of

Q

n

\mathcal {Q}^n

with

p
∈
(
0
,
1
]

p\in (0,1]

fixed, then with high probability

H
∪

Q

p
n

H\cup \mathcal {Q}^n_p

contains

k
k

edge-disjoint Hamilton cycles, for any fixed

k
∈

N

k\in \mathbb {N}

. In particular, both results resolve a long standing conjecture, posed e.g. by Bollobás, that the threshold probability for Hamiltonicity in the random binomial subgraph of the hypercube equals

1

/

2

1/2

. Our techniques also show that, with high probability, for all fixed

p
∈
(
0
,
1
]

p\in (0,1]

the graph

Q

p
n

\mathcal {Q}^n_p

contains an almost spanning cycle. Our methods involve branching processes, the Rödl nibble, and absorption.
The Power of Professional Service Firms
Authors: Sytch Maxim
Published: December 2024

In addition to uncertainty, a second key enabling market condition for supplier-induced demand is the power advantage wielded by professional service firms over their buyers. This advantage is primarily rooted in the firms’ superior expertise and access to information. At the core of professional service firms’ strategic differentiation lies their proficiency in cutting-edge professional expertise. This often manifests as specialized knowledge within a given domain (niche expertise) or the capacity to integrate insights from various related domains (recombinant expertise). Additionally, professionals fortify their power bases through their unique positions in market networks of economic and informational exchange, which help control deal flow and job referrals for buyers’ executives. These power advantages coalesce into a formidable influence, making clients more inclined to adhere to the advice and recommendations of professional service firms both consciously and unconsciously.
Writing Embodiment in Victorian Microscopy
Authors: Kennedy Meegan
Published: December 2024

Victorian microscopists saw observation as deeply embodied, the images emerging through a material entanglement of bodies (of the observer, instrument, apparatus, and object) in a dynamic, unstable system. These ideas echo mid-century work by physiological psychologists, who saw mind (perception, thinking, feeling) as embodied, distributed, and dynamic processes, enacted and affected by automatic or unconscious reflex action, attention, mental training, and fatigue. Microscopists circulated metaphorical and narrative tropes of embodiment through the varied forms of nineteenth-century print culture, to regulate the entanglement of these diverse bodies, and to enculturate microscopy as a difficult but valuable pursuit. They adapted existing concepts (such as beauty, the sublime, natural theology, and fairylands), or invented new ones (such as many-sided comprehension), to promote favored forms of embodiment and build community. Victorians understood wonder and skepticism not as incommensurate approaches to microscopical observation but rather as complementary forms of embodiment. Romantic tropes of wonder (to be distinguished from the intellectual work of imagination) model and solicit particular affective flows. A skeptical, realist approach seeks to train the reader’s eye, hand, body, and judgment, and to formalize the optical, mechanical, and cognitive interchanges of microscopical practice. Some texts offer virtual storyspaces where readers may join the speaker in minute description of an image, in articulated practice, at a soirée, or in exploring an imagined microscopical world. These tropes shape every level of microscopical interest and proficiency, and they illuminate wider patterns of Victorian embodiment, affect, and scientific practice.
Microscopy and Its Audiences
Authors: Kennedy Meegan
Published: December 2024

Victorian microscopy was fostered by a rich and varied print culture, from a lively periodical ecosystem beginning early in the century to surges in book publishing at mid-century. A survey of citations, book reviews, and library holdings suggests a developing canonicity of sources. Victorian microscopists displayed a nationalistic bent in their defense of British efforts, but the work was decidedly international in scope, with important advances from Continental and American investigators and manufacturers. The period is marked by the circulation of microscopical culture through these print forms, which solicit a mixture of research, instruction, community (encouraging both microscopical societies and informal gatherings) and recreation. Texts often address multiple genres and audiences, and so-called “popular” microscopical sources often overlap in important ways with elite references and communities.
Physiological Psychology and Victorian Microscopy
Authors: Kennedy Meegan
Published: December 2024

The Victorian investigators known as physiological psychologists, such as Spencer, Bain, Carpenter, and Lewes, argued that mind (perception, thought, feeling) arises and functions within embodied physical and social systems—that it is distributed, relational, fluid, dynamic. They examined the circulation of thoughts and feelings among individuals and between organism and environment. They emphasized that functions of mind, including unconscious functions and automatic, reflex actions, can be trained to form new habits, but that these functions are also a form of physical labor that cause and are degraded by bodily fatigue. Microscopical investigators considered how the material grounds of perception, thought, and feeling interacted with their own body and the bodies of instrument and object to shape their work. They saw operator, instrument, and object as connected in a nervous network shaped by deliberate action, unconscious or reflex function, and passive or active physical resistance.
Romances of Microscopy
Authors: Kennedy Meegan
Published: December 2024

Victorian microscopists harnessed the affective charge of conventional fantasy worlds by presenting microscopical observation as travel into a foreign landscape or work within a virtual storyspace. Popularizers of microscopy were especially likely to employ these tropes, but they do appear in texts written for researchers also, most often in social settings or paratextual spaces. Writers turn to these more floridly romantic tropes of wonder, such as the fairyland, the Oriental tale, the Gothic phantasmagoria, and the study of unsuspected lifeforms that cavort in a drop of water or invisibly surround us. These texts augmented their sensationalism by emphasis on the hybridity and grotesquerie found in the minute world; but many such texts also solicited the observer’s identification with these anthropomorphized creatures. And while tropes like the phantasmagoria generally mystify visual technology, these writers also sought to demystify microscopical work through relentless instruction.
Articulating Practice
Authors: Kennedy Meegan
Published: December 2024

Victorian microscopists used the skeptical narrative technique that I call articulated practice to model best practices for manipulating the apparatus. This appeared not only in texts reporting on research, where it provides the opportunity for (in Shapin and Schaffer’s terms) virtual witnessing, but also in instructive texts for students and lay readers. In these virtual storyspaces, writers represent their own bodies interacting with the microscope and object; they model a disinterested stance toward their work, narrate the details of their practice, and prescribe certain favored practices and sequences over others. Such passages sometimes anthropomorphize the resistance of microscopical objects, as participants in the narrative, even at times framing tiny “animalcules” as victims of vivisection. The many passages of articulated practice in Victorian microscopy may repel modern readers with their dense prose, but in their assumption that readers will follow these directions and will replicate these physical actions, they formalize microscopical practice and explicitly invite participation in a larger microscopical community.
Wonder and Skepticism
Authors: Kennedy Meegan
Published: December 2024

Victorian microscopists framed wonder and skepticism as different but complementary aspects of the observer’s embodiment. Writers used diverse approaches to manage the productive tensions that arise when wonder (affective response) and skepticism (attention to error, method, and discipline) appear in the same text. Whether written for research settings or as a popularizing effort, some texts isolate elements of wonder or skepticism in paratextual elements; others juxtapose them, weighing them against one another to counterbalance disparate claims; still others combine them within a single thought. The particular form and emphasis of any of these negotiations of wonder and skepticism helps signal textual genre and establish microscopical community.