bluuebunny/crossref_metadata_2025 huggingface dataset:
ISRM: introspective self-supervised reconstruction model for rail surface defect detection and segmentation
Authors: Li Yaxing , Min Yongzhi , Yue Biao
Published: February 2024

The problems of intrinsic imbalance of the sample and interference from complex backgrounds limit the performance of existing deep learning methods when applied to the detection and segmentation of rail surface defects. To address these issues, an introspective self-supervised reconstruction model (ISRM) is proposed, which only requires normal samples in the training phase and incorporates the concept of self-supervised learning into an introspective autoencoder. The training framework of ISRM first extracts general features using a pretrained Feature Extractor. Subsequently, a Feature Transformer transfers the features to the target domain. Next, a synthetic defect embedder embeds Bessel-Gaussian random defects into the feature space. Finally, the asymmetric autoencoder reconstructs the rail surface features back into image space. The transformation of pretrained features into target-oriented features helps mitigate domain bias. Since defects exhibit higher commonality in the feature space relative to the image space, embedding synthetic defects into the feature space effectively improves training efficiency. Moreover, the adversarial training architecture enhances the clarity of reconstructed images. The impact of core parameters on the model performance is analyzed through ablation experiments. The results from comparative experiments demonstrate that ISRM achieves 98.5% and 97.2% accuracy on defect detection and segmentation tasks, respectively, reducing the error rate by 11.8% and 3.4% compared to the current state-of-the-art model.
An efficient and accurate surface defect detection method for quality supervision of wood panels
Authors: Yi Zhihao , Luo Lufeng , Lu Qinghua , Chen Mingyou , Zhu Wenbo , Zhang Yunzhi
Published: February 2024

The wood panel processing sector is integral to the landscape of industrial manufacturing, and automated detection of wood panel surface defects has become an important guarantee for improving the efficiency and quality of processing production. However, due to the diverse scales and shapes of wood panel surface defects, as well as their complex and varied colors and texture characteristics, the efforts to efficiently and accurately detect surface defects in wood panels through existing methods have fallen short. Therefore, the paper proposes an enhanced YOLOx-tiny deep learning network for wood panel surface defect detection. We introduce new modules multi-pooling feature fusion module and comprehensive feature extraction module, instead of the original SPP and Bottleneck modules to enhance key feature extraction and reduce the number of computational parameters. The experimental results conducted on the self-constructed wood panel surface defects dataset show that the mAP of our proposed method is 95.01%, which is 9.58% higher than the original YOLOx-tiny network model, and the defects recall is 91.46%, which is 13.21% higher compared to the original network. Meanwhile, the method is able to reduce 12.22% of computational parameters, which effectively improves the efficiency of the detection of surface defects on wood panels. In summary, the proposed intelligent surface defect detection approach for wood panels, which utilizes an enhanced YOLOx-tiny deep learning network, has yielded notable outcomes in enhancing both accuracy and efficiency. This method holds significant practical relevance for the wood panel manufacturing sector, offering the potential to enhance both production efficiency and quality. It also explores the automation and intelligent technology in the process of man-made board processing, which provides a valuable reference for the research in related fields.
Dynamic sample rate acquisition system based on time-to-digital converter technology
Authors: Wei Shuaimin , Han Xingcheng , Pang Cunsuo , Wang Liming
Published: February 2024

In this paper, we propose a novel acquisition system, which can flexibly adjust the sampling rate according to different sampling requirements. First, we propose a sampling model and conduct feasibility verification experiments on it. The experimental results show that the sampling principle has excellent sampling function. Subsequently, we successfully implemented the system. The system combines the differential comparator of Field-Programmable Gate Array (FPGA) with the characteristics of Time-to-digital converter (TDC), which makes full use of the hardware resources of FPGA to realize efficient digital sampling and reconstruction of unknown signals. Among them, the TDC we designed has a time error of less than 100 ps at sampling rates lower than 50 MSps the sampled signal is transmitted via Ethernet, and the measured on-chip data link throughput rate reaches 600 Mbps the sampled information is decoded, fitted and reconstructed in the host computer. In addition, we have thoroughly studied the factors affecting the sampling quality in this acquisition method and summarized the sampling laws after acquiring multiple signals. To ensure the minimum distortion rate, we choose the threshold signal amplitude as 0–5 times of the highest amplitude of the sampled signal, and select the frequency as 10–30 times. Regarding the system resource consumption, the LUT utilization rate is 12.22%, the Slice utilization rate is 23.37%, and the overall design power consumption is 2.094 W. After a comprehensive evaluation of the performance and comparison with the literature (Kalisz et al 1997 IEEE Trans. Instrum. Meas.
46 51–55), it can be concluded that the system has the advantages of small error, high accuracy, and dynamic sampling function. Summarizing this paper, the system shows good engineering practicability and feasibility in the measurement field.
Off-axis bifocal metalens for displacement measurement
Authors: Cao Danlin , Li Dan , Hu Jianyang , Li Chang , Chen Chen , Wang Yiqun , Lin Jie , Jin Peng
Published: February 2024

Metasurface is a new type of micro-optical element developed in recent years. It can intelligently modulate electromagnetic waves by adjusting the geometrical parameters and arrangement of dielectric structures. In this paper, a bifocal metalens based on modulation of propagation phase was designed for the potential application in displacement measurement. The phase of the bifocal lens is designed by the optical holography-like method, which is verified by the scalar diffraction theory. We designed a square aperture lens with a side length of 200 μm to realize two focal spots with focal lengths of 900 and 1100 μm. The two focal spots aren’t on one optical axis. The polarization insensitive TiO2 cylinders are chosen as structure units. Four structures with different radius were selected to achieve the four phase steps. We fabricated the designed bifocal metalens using electron beam lithography and atomic layer deposition techniques, and measured the light intensity in the areas near the two foci in the direction of the longitudinal axis. The differential signal was calculated, from which we obtained a linear interval. It demonstrates the ability of bifocal differential measurement to be applied to displacement measurement. Because the metasurfaces production process is semiconductor compatible, the bifocal lens is easy to integrate and can be used for miniaturized displacement measurements, micro-resonators, acceleration measurements, and so on.
Exfoliated MXene–AuNPs hybrid in sensing and multiple catalytic hydrogenation reactions
Authors: Kumar Yogesh , Thomas Tijin , Pérez-Tijerina E , Bogireddy N K R , Agarwal V
Published: February 2024

The increasing use of nanomaterials in consumer products is expected to lead to environmental contamination sometime soon. As water pollution is a pressing issue that threatens human survival and impedes the promotion of human health, the search for adsorbents for removing newly identified contaminants from water has become a topic of intensive research. The challenges in the recyclability of contaminated water continue to campaign the development of highly reusable catalysts. Although exfoliated 2D MXene sheets have demonstrated the capability towards water purification, a significant challenge for removing some toxic organic molecules remains a challenge due to a need for metal-based catalytic properties owing to their rapid response. In the present study, we demonstrate the formation of hybrid structure AuNPs@MXene (Mo2CT
x
) during the sensitive detection of Au nanoparticle through MXene sheets without any surface modification, and subsequently its applications as an efficient catalyst for the degradation of 4-nitrophenol (4-NP), methyl orange (MO), and methylene blue (MB). The hybrid structure (AuNPs@MXene) reveals remarkable reusability for up to eight consecutive cycles, with minimal reduction in catalytic efficiency and comparable apparent reaction rate constant (K
app) values for 4-NP, MB, and MO, compared to other catalysts reported in the literature.
MAPbI3 perovskite photodetectors for high-performance optical wireless communication
Authors: Zheng Aosheng , Zhang Haijian , Zhang Yating , Wang Silei , Ding Guanchu , Song Chunyu , Li Mengyao , Yang Fan , Liu Yanyan , Yao Jianquan
Published: February 2024

High-sensitivity and fast-response photodetectors (PDs) are vital part of optical wireless communication (OWC) system. In this work, we develop an organic–inorganic hybrid perovskite material (MAPbI3) based p–i–n structured PD. By optimizing the precursor solution concertation, the PD showed a high responsivity of 0.98 A W−1, a fast response time t
rise/t
fall of 12/12.5 μs, a specific detectivity of 2.62 × 1013 Jones, and the f−3dB of 24 kHz under the 532 nm laser and −0.2 V bias voltage. Furthermore, we designed an OWC system based on the prepared PD. With the baud rate of 19200 bps, the system exhibits a bit error rate less than 10−6, and it can realize 9.63 m long-distance communication and quick transmission applications such as strings, texts, photos, and audios. Our work demonstrates the great application potential of perovskite PDs in the field of optical communication.
Quasi-periodic waves to the defocusing nonlinear Schrödinger equation
Authors: Zhang Ying-Nan , Hu Xing-Biao , Sun Jian-Qing
Published: February 2024

A direct approach for the quasi-periodic wave solutions to the defocusing nonlinear Schrödinger equation is proposed based on the theta functions and Hirota’s bilinear method. We transform the problem into a system of algebraic equations, which can be formulated into a least squares problem and then solved by using numerical iterative methods. A rigorous asymptotic analysis demonstrates that these solutions can be classified into two categories: quasi-periodic oscillatory waves and quasi-periodic dark solitons. Singular behaviors may arise in the former case. The numerical results obtained for both the

(
1
+
1
)

-dimensional and

(
2
+
1
)

-dimensional equations are consistent with the theoretical results. Additionaly, the system of algebraic equations can be further extended to address the Riemann–Schottky problem for hyperelliptic curves with 2 infinite points.
Visualising relativity: assessing high school students’ understanding of complex physics concepts through AI-generated images
Authors: de Souza Maira Giovana , Won Mihye , Treagust David , Serrano Agostinho
Published: February 2024

This study investigates how students utilized artificial intelligence (AI)-generated images to represent their understanding of general relativity concepts. Ten high school students participated in an extracurricular course on relativity theory. Using AI chatbot, these students created visual representations of ‘relativity’ before and after the course. The produced images, the accompanying prompts, student interviews, and their test scores were analysed to examine students’ conceptual understanding and interactions with AI. Students with a clearer understanding of relativity tended to focus their prompts on more central concepts like spacetime deformation. In contrast, those with a weaker understanding leaned towards more tangential ideas. The clarity of their prompts was directly linked to more effective AI interactions, leading to more meaningful image generation. Despite this, some students faced challenges in crafting coherent prompts, resulting in less relevant images, indicating that understanding the concept does not always translate into successful AI engagement. The study underscores the potential of AI-generated images as a tool to illuminate student conceptualisation and interaction skills with AI in the context of complex physics concepts, offering a novel approach to evaluating understanding in advanced scientific topics.
Thirty-one physics words with unusual origins
Authors: Binder P-M
Published: February 2024

The unusual etymology of 31 words commonly used in introductory physics is presented in detail. This work can inspire class conversations on the interplay between science and culture, the mutual influence of cultures, and doing physics in non-English languages.
Rapid patient-specific FEM meshes from 3D smart-phone based scans
Authors: Murphy Ethan K , Smith Joel , Kokko Michael A , Rutkove Seward B , Halter Ryan J
Published: February 2024

Objective. The objective of this study was to describe and evaluate a smart-phone based method to rapidly generate subject-specific finite element method (FEM) meshes. More accurate FEM meshes should lead to more accurate thoracic electrical impedance tomography (EIT) images. Approach. The method was evaluated on an iPhone® that utilized an app called Heges, to obtain 3D scans (colored, surface triangulations), a custom belt, and custom open-source software developed to produce the subject-specific meshes. The approach was quantitatively validated via mannequin and volunteer tests using an infrared tracker as the gold standard, and qualitatively assessed in a series of tidal-breathing EIT images recorded from 9 subjects. Main results. The subject-specific meshes can be generated in as little as 6.3 min, which requires on average 3.4 min of user interaction. The mannequin tests yielded high levels of precision and accuracy at 3.2 ± 0.4 mm and 4.0 ± 0.3 mm root mean square error (RMSE), respectively. Errors on volunteers were only slightly larger (5.2 ± 2.1 mm RMSE precision and 7.7 ± 2.9 mm RMSE accuracy), illustrating the practical RMSE of the method. Significance. Easy-to-generate, subject-specific meshes could be utilized in the thoracic EIT community, potentially reducing geometric-based artifacts and improving the clinical utility of EIT.
A new FILDSIM model for improved velocity-space sensitivity modelling and reconstructions
Authors: Schmidt Bo S , Poley-Sanjuán Jesús , Rueda-Rueda José , Galdon-Quíroga Joaquín , Baquero-Ruiz Marcelo , Järleblad Henrik , Reman Bernard C G , Rud Mads , Valentini Andrea , García-Muñoz Manuel , Salewski Mirko
Published: February 2024

We present a new version of the FILDSIM code (Galdon-Quíroga et al 2018 Plasma Phys. Control. Fusion
60 105005), which significantly refines the modelling of the fast-ion loss detector (FILD) signal. We demonstrate that the FILD weight functions computed using this new version of FILDSIM are more accurate relative to synthetic benchmarks than those computed using the previous version. Thus, the new version enables higher-quality velocity-space sensitivity modelling and reconstructions. We validate the improvements on experimental data from discharge #75620 at TCV. Additionally, we present a novel approach for characterizing FILDs through a gross FILD measurement and a gross weight function based on the calculations from the new version of FILDSIM. We use them to characterize the TCV FILD.
Quantification of losses in bent waveguides within DBR-RW laser diodes emitting at 785 nm
Authors: Theurer Lara Sophie , Koester Jan-Philipp , Müller André , Maiwald Martin , Knigge Andrea , Sumpf Bernd , Tränkle Günther
Published: February 2024

An experimental study of straight and bent distributed Bragg reflector (DBR) ridge waveguide (RW) lasers and Fabry–Pérot (FP) RW lasers emitting at 785 nm is presented. To determine the losses introduced by the bent waveguides within DBR-RW lasers, different laser designs were manufactured and characterized. The bent waveguides investigated here within DBR-RW laser diodes are sine-shaped S-bends. S-bends with three different lateral offsets are manufactured. The experimental characterization of FP lasers and the straight DBR-RW lasers with different coatings at the rear facet enables a rough estimation of the losses caused by the DBR grating and the determination of the DBR reflectivity. Furthermore, additional losses in the bent DBR-RW lasers caused by the S-bend (i.e. radiation and scattering losses) are quantified by comparing them to the straight DBR-RW lasers. Within the active resonator, the S-bend losses amount to α
Bend = 0.6 cm−1 (α
Bend = 0.5 dB) for the smallest manufactured lateral S-bend offset H = 40 μm. For both straight and bent DBR-RW lasers spectrally narrow single-mode emission is obtained. A lateral beam width of 3.8 μm (using second moments) and a lateral far-field angle of about 18° and 19.5° (using second moments) for the straight and S-bend DBR-RW are measured, respectively. This gives a lateral beam propagation ratio of 1.2 and 1.3 (using second moments) for straight and S-bend DBR-RW, respectively. The radiation loss in dependency of the lateral S-bend offset is simulated and compared to experimentally estimated S-bend losses for bent DBR-RW lasers (H = 40 μm, H = 60 μm and H = 70 μm).
Sensory adaptation in a continuum model of bacterial chemotaxis—working range, cost-accuracy relation, and coupled systems
Authors: Kharbanda Vansh , Sabass Benedikt
Published: February 2024

Sensory adaptation enables organisms to adjust their perception in a changing environment. A paradigm is bacterial chemotaxis, where the output activity of chemoreceptors is adapted to different baseline concentrations via receptor methylation. The range of internal receptor states limits the stimulus magnitude to which these systems can adapt. Here, we employ a highly idealized, Langevin-equation based model to study how the finite range of state variables affects the adaptation accuracy and the energy dissipation in individual and coupled systems. Maintaining an adaptive state requires constant energy dissipation. We show that the steady-state dissipation rate increases approximately linearly with the adaptation accuracy for varying stimulus magnitudes in the so-called perfect adaptation limit. This result complements the well-known logarithmic cost-accuracy relationship for varying chemical driving. Next, we study linearly coupled pairs of sensory units. We find that the interaction reduces the dissipation rate per unit and affects the overall cost-accuracy relationship. A coupling of the slow methylation variables results in a better accuracy than a coupling of activities. Overall, the findings highlight the significance of both the working range and collective operation mode as crucial design factors that impact the accuracy and energy expenditure of molecular adaptation networks.
The suppression of finite size effect within a few lattice sites
Authors: Liu Tao , Bai Kai , Zhang Yicheng , Wan Duanduan , Lai Yun , Chan C T , Xiao Meng
Published: February 2024

Boundary modes localized on the boundaries of a finite-size lattice experience a finite size effect (FSE) that could result in unwanted couplings, crosstalks and formation of gaps even in topological boundary modes. It is commonly believed that the FSE decays exponentially with the size of the system and thus requires many lattice sites before eventually becoming negligibly small. Here we consider a two-dimensional strip geometry that is periodic along one direction and truncated along the other direction, in which we identify a special type of FSE of some boundary modes that apparently vanishes at some particular wave vectors along the periodic direction. Meanwhile, the number of wave vectors where the FSE vanishes equals the number of lattice sites across the strip. We analytically prove this type of FSE in a simple model and prove this peculiar feature. We also provide a physical system consisting of a plasmonic sphere array where this FSE is present. Our work points to the possibility of almost arbitrarily tunning of the FSE, which facilitates unprecedented manipulation of the coupling strength between modes or channels such as the integration of multiple waveguides and photonic non-abelian braiding.
Ambipolar Diffusion with a Polytropic Equation of State
Authors: Bottesi Blake J. , Fatuzzo Marco , Holden Lisa , Herweck Kendra
Published: February 2024

Ambipolar diffusion is the mechanism believed to be responsible for the loss of magnetic support in dense molecular cloud cores, and is therefore likely to play a key role in the star formation process. As such, this mechanism has been studied extensively both semianalytically and numerically. We build upon this existing body of work by considering a one-dimensional self-gravitating gas with a polytropic equation of state (P ∝ ρ

ϵ
), and consider cases that range from softer (ϵ < 1) to stiffer (ϵ > 1) than isothermal. Our results indicate that the diffusion time is not very sensitive to the polytropic exponent ϵ when stiffer than isothermal, but is sensitive to the exponent when softer than isothermal. Additionally, the presence of magnetic and density fluctuations causes the ambipolar diffusion process to speed up, with the shortest diffusion times obtained for gases with large initial magnetic to gas pressure ratios and fairly soft equations of state. However, the diffusion time starts to increase significantly for ϵ ≲ 0.5, indicating that such soft equations of state are inconsistent with observations.
All-sky Guide Star Catalog for CSST
Authors: Feng Hui-Mei , Cao Zi-Huang , Lam Man I , Li Ran , Tian Hao , Yin Da-Yi , Yang Yuan-Yu , Zhang Xin , Fan Dong-Wei , Dong Yi-Qiao , Li Xin-Feng , Wang Wei , Li Long , Jones Hugh R. A. , Tao Yi-Han , Nie Jia-Lu , Wang Pei-Pei , Liu Mao-Yuan , Yang He-jun , Liu Chao
Published: February 2024

The China Space Station Telescope (CSST) is a two-meter space telescope with multiple back-end instruments. The Fine Guidance Sensor (FGS) is an essential subsystem of the CSST Precision Image Stability System to ensure the required absolute pointing accuracy and line-of-sight stabilization. In this study, we construct the Main Guide Star Catalog for FGS. To accomplish this, we utilize the information about the FGS and object information from the Gaia Data Release 3. We provide an FGS instrument magnitude and exclude variables, binaries, and high proper motion stars from the catalog to ensure uniform FGS guidance capabilities. Subsequently, we generate a HEALPix index, which provides a hierarchical tessellation of the celestial sphere, and employ the Voronoi algorithm to achieve a homogeneous distribution of stars across the catalog. This distribution ensures adequate coverage and sampling of the sky. The performance of the CSST guide star catalog was assessed by simulating the field of view of the FGS according to the CSST mock survey strategy catalog. The analysis of the results indicates that this catalog provides adequate coverage and accuracy. The catalog's performance meets the FGS requirements, ensuring the functioning of the FGS and its guidance capabilities.
The model validation for trip assignment using all or nothing and user’s equilibrium method
Authors: Mahmudah Amirotul M. H. , Hartono W , Lestari R , Rachmawati S , Septiasworo D V
Published: February 2024

In transportation planning, an accurate transportation model is crucial. The trip-based approach is widely used, which relies on the four-step model (FSM) for transportation modeling. The model generates an origin-destination (O-D) Matrix as the starting point, which is then used to determine traffic flow on the road network through a trip assignment. This approach is superior because the (O-D) Matrix is a result of the interaction between land use and accessibility. In Boyolali Regency, research was conducted using traffic volume data that reflected the conditions at the beginning of 2023. The gravity model was used to determine trip distribution for this study, and the Least Squares method and negative exponential function calibrated the model. The study aim is to compare the performance of All or Nothing and User’s Equilibrium assignment methods using the EMME/3 software. The results showed that All or Nothing had a higher R2 value of 0.913 compared to User’s Equilibrium’s 0.911, suggesting that the All or Nothing assignment method is more suitable for Boyolali Regency. The research predicted that the total movement of Boyolali Regency in 2023 would be 12,354 pcu/hour, with most of the movement being external-external. As Boyolali Regency is a transit area, vehicles only pass through it.
Assessing the impact of Medan-Stabat toll road on carbon monoxide pollutant in arterial roads
Authors: Anas Ridwan , Nasution Zaid Perdana , Hasnan Adam
Published: February 2024

Carbon monoxide is the result of the combustion of motorized vehicles which can pollute the air and will cause negative impacts to the health of human beings. The development of a toll road is initiated in the routes of an arterial road which have been causing congestion or terrible traffic jams, and is expected directly to reduce the amount of traffic jams and to increase the speed of travel, and indirectly to reduce air pollution in the arterial roads. The objective of this paper is to predict the effects of the Medan-Stabat Toll Road operation to the CO pollutant contents in the arterial roads. The results indicate that the level of pollution is reduced up to 10 % and 25% due to traffic shifting on the arterial roads to the toll road.
Addressing Indonesia’s biggest road safety challenge: Reducing motorcycle deaths
Authors: Ayuningtyas Kardina N.S , Grzebieta Raphael , Olivier Jake , Caponecchia Carlo
Published: February 2024

Motorcyclists are the largest contributor to road fatalities in Indonesia, with the main causal factors found to be speeding and not wearing a helmet. One of the most efficient ways to reduce road deaths in Indonesia would be to reduce speeding behaviour and increase helmet wearing by strengthening speed and helmet wearing enforcement combined with education. Stronger enforcement combined with education have been shown to be highly effective in reducing fatalities in other countries. This study assesses the benefits of stronger enforcement on speed limit and helmet wearing. It also explores what are the most effective strategies to strengthen enforcement using fixed and mobile speed cameras, point to point speed cameras and AI technology that can be used to enforce helmet wearing rates. The paper concludes with an estimation of the potential benefits if such stronger enforcement were implemented in Indonesia.
Risk Factors associated with Stress-related Riding Behavior among Indonesian Motorcyclists
Authors: Anggraini Renni , Isya Muhammad , Fadhly Noer , Mutiawati Cut
Published: February 2024

The risk of road accidents is influenced by various elements, particularly human factor. In Indonesia, motorcycles contribute significantly to accidents due to insufficient knowledge of traffic laws and a lack of awareness about safe riding practices. Stress-related riding behavior, which may lead to this incident, is closely linked to driving discipline. Therefore, this study aimed to examine stress-related behavior as the risk factor in road accidents among motorcyclists. To achieve this, a self-reported questionnaire was distributed to 300 motorcyclists in Banda Aceh City and surrounding areas in Aceh Province. Factor analysis was used to simplify the number of indicators included, after which they were prioritized in order of importance. The results showed the most influential indicators out of the 26 considered in this study. A total of 3 underlying factor were identified, comprising anxious riding, aggressive riding, and anger. By addressing the risk factor associated with stress-related riding behavior, road safety in Indonesia was enhanced.
Radiation shielding assessment for interventional radiology personnel: Geant4 dosimetry of lead-free compositions
Authors: Moradi F , Jalili M , Saraee Kh Rezaee Ebrahim , Abdi M R , Rashid H A Abdul
Published: February 2024

The inherent biological hazards associated with ionizing radiation necessitate the implementation of effective shielding measures, particularly in medical applications. Interventional radiology, in particular, poses a unique challenge as it often exposes medical personnel to prolonged periods of high x-ray doses. Historically, lead and lead-based compounds have been the primary materials employed for shielding against photons. However, the drawbacks of lead, including its substantial weight causing personnel’s inflexibility and its toxicity, have raised concerns regarding its long-term impact on both human health and the environment. Barium tantalate has emerged as a promising alternative, due to its unique attenuation properties against low-energy x-rays, specifically targeting the weak absorption area of lead. In the present study, we employ the Geant4 Monte Carlo simulation tool to investigate various formulations of barium tantalate doped with rare earth elements. The aim is to identify the optimal composition for shielding x-rays in the context of interventional radiology. To achieve this, we employ a reference x-ray spectrum typical of interventional radiology procedures, with energies extending up to 90 keV, within a carefully designed simulation setup. Our primary performance indicator is the reduction in air kerma transmission. Furthermore, we assess the absorbed doses to critical organs at risk within a standard human body phantom protected by the shield. Our results demonstrate that specific concentrations of the examined rare earth impurities can enhance the shielding performance of barium tantalate. To mitigate x-ray exposure in interventional radiology, our analysis reveals that the most effective shielding performance is achieved when using barium tantalate compositions containing 15% Erbium or 10% Samarium by weight. These findings suggest the possibility of developing lead-free shielding solutions or apron for interventional radiology personnel, offering a remarkable reduction in weight (exceeding 30%) while maintaining shielding performance at levels comparable to traditional lead-based materials.
A thermodynamic approach to optimization in complex quantum systems
Authors: Imparato Alberto , Chancellor Nicholas , De Chiara Gabriele
Published: February 2024

We consider the problem of finding the energy minimum of a complex quantum Hamiltonian by employing a non-Markovian bath prepared in a low energy state. The energy minimization problem is thus turned into a thermodynamic cooling protocol in which we repeatedly put the system of interest in contact with a colder auxiliary system. By tuning the internal parameters of the bath, we show that the optimal cooling is obtained in a regime where the bath exhibits a quantum phase transition in the thermodynamic limit. This result highlights the importance of collective effects in thermodynamic devices. We furthermore introduce a two-step protocol that combines the interaction with the bath with a measure of its energy. While this protocol does not destroy coherence in the system of interest, we show that it can further enhance the cooling effect.
Ion correlations in quaternary ionic liquids electrolytes
Authors: Tong Jiahuan , Liang Xiaodong , von Solms Nicolas , Huo Feng , Zhuang Bilin
Published: February 2024

Lithium-ion batteries are currently the most popular and widely used energy storage devices, almost omnipresent within modern society in portable devices, electrical vehicles, energy storage stations, and so on. The demand for more efficient, more durable, and more sustainable batteries is rapidly growing. The electrolyte is a key element to improve the performance of lithium-ion batteries. In this work, we focus on quaternary ionic liquid electrolyte (ILE), which uses a four-component ionic liquid as the solvent. Quaternary ILE has found wide applications in energy storage systems, but the ion transport in the electrolyte has not been fully characterized to provide the best strategy for performance optimisation. In this work, we systematically analyse the ion transport in the quaternary ILE and uncover how the correlations between various ions affect the conductivity of the electrolyte. We have found that lithium ions are transported in charge clusters, leading to a negative effective transference number of lithium ions. Furthermore, we identify the stable cluster conformations in ILE by cluster analysis and quantum chemical computing. This work highlights the necessity of considering ion correlations in multi-component electrolyte systems.
Miniaturized droplets flow reactor for one-step highly controlled synthesis of SnO2 quantum dots at room temperature
Authors: Katoch Vibhav , Shanmugam Naveen Kumar Arjunan , Rohal Alisha , Singh M Ramananda , Kaushal Manish , Prakash Bhanu
Published: February 2024

In recent years, the conventional methods of synthesizing nanomaterials have been surpassed by the emergence of the microfluidics route, which has brought forth numerous advantages and transformed the domain of nanomaterial synthesis. However, the synthesis of semiconducting oxide nanomaterials, specifically Tin oxide (SnO2), remains a crucial area of research due to its remarkable advantages as a viable alternative to toxic and costly materials. Additionally, SnO2 quantum dots (QDs) exhibit immense potential across a diverse range of applications due to their exceptional optical and electrical properties. The existing synthesis methods for SnO2 QDs are either time-consuming or involve high-temperature conditions. To address these challenges, the droplet-based microfluidic technique has emerged as a promising approach for the controlled synthesis of various semiconducting nanomaterials. This article highlights the synthesis of SnO2 QDs with tunable size through the utilization of a droplet-based microfluidic technique, providing precise control over droplet volumes. X-ray diffraction analysis verified the presence of rutile-type tetragonal structure in SnO2 QDs. From the transmission electron microscopy analysis, the average particle size was calculated to be 1.90 nm, 2.09 nm and 2.63 nm for the volume of droplet corresponding to 33.25 μl, 27.84 μl and 18.25 μl respectively. Furthermore, with a decrease in particle size a tunabilty in optical bandgap, from 4.60 eV to 4.00 eV was observed. This work provides insights into the influence of droplet volume on the particle size which in turn affects the associated properties of SnO2 QDs in a droplet-based microfluidic synthesis system.
Frequency selective surface design with multifunction response for multibands
Authors: Shah Gulab , Cao Qunsheng
Published: February 2024

The active frequency selective surface (AFSS), which can switch between five bands and has multifunctional response, is novel inclusion in the spatial filters domain. The proposed AFSS consists of double orthogonal metal layers disposed on two sides of a substrate. This active structure adopts a four-bit scheme with embedded parallel bias lines used to feed four PIN diodes. The nine independently controllable combinations procure nine different frequency responses. The operating nine combinations switch between five bands centered at frequencies of 1.54 GHz, 2.21 GHz, 2.94 GHz, 2.99 GHz and 3.2 GHz, which have corresponding fractional bandwidths of 18.3%, 26.6%, 12.1%, 8.4% and 1.3%, respectively. These frequencies cover the two, polarization and electromagnetic, switching functions. This multiband and multifunctional design also achieves reasonable angular stability without spurious resonances. Justification to how the proposed design works is provided through surface current distribution, electric field intensity and equivalent circuit model. The simulated multiband design is fabricated and proved its authenticity by the free space measurements scheme.
Effect of double-pass friction stir welding and base materials position on the microstructural and mechanical behaviors of the dissimilar aluminum welded joints of AA6061 and AA2017
Authors: Nukathoti Raja Sekhar , Vanthala Varaha Siva Prasad , Battina N Malleswararao , Chirala Hari Krishna
Published: February 2024

Friction stir welding (FSW) is a method of joining solid materials, where the parent metal’s melting temperature is below the point of amalgamation. FSW is a successful method for combining various ferrous and non-ferrous matrix materials. Many researchers’ studies suggested that FSW is suitable for both soft and high melting-point materials by changing the conditional attributes. A defect-free dissimilar weld joint of the alloys AA2017 and AA6061 was fabricated for the current investigation, and the effect of multi-pass friction stir welding (MPFSW) on the development of mechanical and different microstructural behaviors has been investigated. Welding conditions were a constant 1600 rpm weld tool rotational speed, a transverse speed is 32 mm min−1, and a tilt angle of 0°. As a consequence of the pinning effect, the results showed that increasing the number of welding passes in FSW from single to double improved the particle dispersion, which in turn improved the tensile strength, and micro-hardness of the FSWed joint. The primary objectives of this study investigate the strength that was improved because of the rise in the number of passes as well as the effective bonding of the materials’ weld interface, which gives tailor-welded blanks (TWBs) a considerably stronger joint. The findings revealed that the TWB joints’ metallurgical and mechanical properties are extremely varied from single-pass to double-pass, and the position of the base materials can significantly affect the joint properties that are produced.
Local sign stability and its implications for spectra of sparse random graphs and stability of ecosystems
Authors: Valigi Pietro , Neri Izaak , Cammarota Chiara
Published: February 2024

We study the spectral properties of sparse random graphs with different topologies and type of interactions, and their implications on the stability of complex systems, with particular attention to ecosystems. Specifically, we focus on the behaviour of the leading eigenvalue in different type of random matrices (including interaction matrices and Jacobian-like matrices), relevant for the assessment of different types of dynamical stability. By comparing numerical results on Erdős–Rényi and Husimi graphs with sign-antisymmetric interactions or mixed sign patterns, we propose a sufficient criterion, called strong local sign stability, for stability not to be affected by system size, as traditionally implied by the complexity-stability trade-off in conventional models of random matrices. The criterion requires sign-antisymmetric or unidirectional interactions and a local structure of the graph such that the number of cycles of finite length do not increase with the system size. Note that the last requirement is stronger than the classical local tree-like condition, which we associate to the less stringent definition of local sign stability, also defined in the paper. In addition, for strong local sign stable graphs which show stability to linear perturbations irrespectively of system size, we observe that the leading eigenvalue can undergo a transition from being real to acquiring a nonnull imaginary part, which implies a dynamical transition from nonoscillatory to oscillatory linear response to perturbations. Lastly, we ascertain the discontinuous nature of this transition.
Pathways to discontinuous transitions in interacting contagion dynamics
Authors: Lamata-Otín Santiago , Gómez-Gardeñes Jesús , Soriano-Paños David
Published: February 2024

Yet often neglected, dynamical interdependencies between concomitant contagion processes can alter their intrinsic equilibria and bifurcations. A particular case of interest for disease control is the emergence of discontinuous transitions in epidemic dynamics coming from their interactions with other simultaneous processes. To address this problem, here we propose a framework coupling a standard epidemic dynamics with another contagion process, presenting a tunable parameter shaping the nature of its transitions. Our model retrieves well-known results in the literature, such as the existence of first-order transitions arising from the mutual cooperation of epidemics or the onset of abrupt transitions when social contagions unidirectionally drive epidemics. We also reveal that negative feedback loops between simultaneous dynamical processes might suppress abrupt phenomena, thus increasing systems robustness against external perturbations. Our results render a general perspective toward finding different pathways to abrupt phenomena from the interaction of contagion processes.
Harnessing causal forests for epidemiologic research: key considerations
Authors: Shiba Koichiro , Inoue Kosuke
Published: February 2024

Assessing heterogeneous treatment effects (HTEs) is an essential task in epidemiology. The recent integration of machine learning into causal inference has provided a new, flexible tool for evaluating complex HTEs: causal forest. In a recent paper, Jawadekar et al (Am J Epidemiol. 2023;192(7):1155-1165) introduced this innovative approach and offered practical guidelines for applied users. Building on their work, this commentary provides additional insights and guidance to promote the understanding and application of causal forest in epidemiologic research. We start with conceptual clarifications, differentiating between honesty and cross-fitting, and exploring the interpretation of estimated conditional average treatment effects. We then delve into practical considerations not addressed by Jawadekar et al, including motivations for estimating HTEs, calibration approaches, and ways to leverage causal forest output with examples from simulated data. We conclude by outlining challenges to consider for future advancements and applications of causal forest in epidemiologic research.
Independence and impartiality: Australia’s arbitrator bias test
Authors: Garrett Emma
Published: February 2024

This article examines Australia’s arbitrator bias test to reveal its underlying contradictions and ambiguity and suggests that the legislation is amended to remedy these flaws and ensure Australia stays in line with international best practice. In 2010, section 18A of the International Arbitration Act 1974 (Cth) introduced the arbitrator bias test into Australian statute. The provision failed to specify both limbs of the test and relied on Gough, an outdated English case. This produced two opposing decisions from Australia’s federal judiciary: Sino Dragon and Hui. The uncertainty of Australia’s arbitrator bias test strikes at the heart of the process as the independence and impartiality of arbitrators is a fundamental pillar of international commercial arbitration. After critically analysing the progression of England’s approach to the arbitrator bias test over the past century to date, I conclude that the inherent unclearness of Australia’s approach needs to be remedied by the real possibility test being codified in Australian statute. This test reflects the Australian federal judiciary’s most recent approach. My analysis also reveals it is the most appropriate test. By clarifying Australia’s arbitrator bias test those associating with Australia’s international commercial arbitration system have the requisite certainty and clarity to engage with ease.
Lower Gluteal Liposuction Combined With Upper Gluteal and Infragluteal Region Fat Grafting: A Novel Concept to Improve Gluteal Ptosis
Authors: Yang Mingzi , Li Jiyang , Dong Weiwei , Lv Qianwen , Qi Yue , Han Xuefeng , Qi Zuoliang , Ma Gui-e , Gu Yunpeng
Published: February 2024

Background

Gluteal ptosis results in a severe disturbance of gluteal aesthetics. Currently, satisfactory procedures for improving gluteal ptosis are lacking.

Objectives

To improve gluteal ptosis, the authors propose a novel concept of combined liposuction of the lower gluteal region and fat grafting to the upper gluteal and infragluteal regions, and verify its efficacy and safety.

Methods

Patients who underwent liposuction of the lower gluteal region combined with fat grafting to the upper gluteal and infragluteal regions between January 2020 and July 2023 were retrospectively reviewed. Postoperative changes in the gluteal ptosis grade, complications, and patient satisfaction were evaluated.

Results

A total of 28 patients were enrolled in this study; 21 (75.0%) patients had gluteal ptosis grade 4 and 7 (25.0%) patients had gluteal ptosis grade 5. The median fat removal volume was 210 mL, and the median fat graft injected volume was 355 mL in the gluteal region and 180 mL in the infragluteal region. All patients showed improvement in gluteal ptosis; 16 (57.1%) patients improved by 1 grade and 12 (42.9%) patients showed a 2-grade improvement. All patients were satisfied with their posttreatment outcomes. Only 1 patient showed lateral translocation of the fat graft. No other complications were observed.

Conclusions

Liposuction of the lower gluteal region combined with fat grafting to the upper gluteal and infragluteal regions is effective in improving gluteal ptosis, with a low risk of complications and high patient satisfaction.

Level of Evidence: 3
From Tip of Brush to Tip of Knife: The Relationship Between Post-mastectomy Breast Reconstruction and the Classical Arts
Authors: Wood Matabele Kasey Leigh , Nkana Zeeda H , Seitz Allison J , Edalatpour Armin , Mahajan Ashish Y , Poore Samuel O
Published: February 2024

Breast reconstruction is highly complex, requiring navigation of not only clinical and operative realities, but of patient expectations as well. The authors sought to identify historical art pieces that exhibit breast asymmetries and deformities for comparison with photographs of breast reconstruction patients seen at the clinic of the senior author (S.O.P.) to demonstrate that achievement of perfect breast cosmesis is challenging in both breast reconstruction and in the classical arts. Open access libraries and Creative Commons images were reviewed to identify appropriate works of art from various time periods and geographic locations. Following artwork selection, photographs of breast reconstruction patients were reviewed and paired with selected artworks exhibiting cosmetically similar breasts. A total of 8 pieces of selected historic art were found to have at least 1 matching patient photograph, with 9 correlative patient photographs ultimately chosen. Common breast asymmetries and deformities identified included ptosis, asymmetric chest wall placement, asymmetric nipple placement, and absence of the nipple. This review identified diverse artworks of varying styles spanning vast expanses of both geography and time that exhibited breast deformities and asymmetries commonly encountered in patients seeking revision of breast reconstruction. This underscores that creating the cosmetically ideal breast is difficult both in the operating room and the art studio. Importantly, the authors emphasized that the arts frequently celebrate that which is considered beautiful, although to the trained eye of a plastic surgeon that which is considered beautiful is often classified as dysmorphic or asymmetric.