bluuebunny/crossref_metadata_2025 huggingface dataset:
Hierarchical bubble size distributions in coarsening wet liquid foams
Authors: Galvani Nicolò , Pasquet Marina , Mukherjee Arnab , Requier Alice , Cohen-Addad Sylvie , Pitois Olivier , Höhler Reinhard , Rio Emmanuelle , Salonen Anniina , Durian Douglas J. , Langevin Dominique
Published: September 2023

Coarsening of two-phase systems is crucial for the stability of dense particle packings such as alloys, foams, emulsions, or supersaturated solutions. Mean field theories predict an asymptotic scaling state with a broad particle size distribution. Aqueous foams are good model systems for investigations of coarsening-induced structures, because the continuous liquid as well as the dispersed gas phases are uniform and isotropic. We present coarsening experiments on wet foams, with liquid fractions up to their unjamming point and beyond, that are performed under microgravity to avoid gravitational drainage. As time elapses, a self-similar regime is reached where the normalized bubble size distribution is invariant. Unexpectedly, the distribution features an excess of small roaming bubbles, mobile within the network of jammed larger bubbles. These roaming bubbles are reminiscent of rattlers in granular materials (grains not subjected to contact forces). We identify a critical liquid fractionϕ∗, above which the bubble assembly unjams and the two bubble populations merge into a single narrow distribution of bubbly liquids. Unexpectedly,ϕ∗is larger than the random close packing fraction of the foamϕrcp. This is because, betweenϕrcpandϕ∗, the large bubbles remain connected due to a weak adhesion between bubbles. We present models that identify the physical mechanisms explaining our observations. We propose a new comprehensive view of the coarsening phenomenon in wet foams. Our results should be applicable to other phase-separating systems and they may also help to control the elaboration of solid foams with hierarchical structures.
Tangut and Horpa languages
Authors: Beaudouin Mathieu
Published: September 2023

Fieldwork from the past decade has yielded new data from a cluster of languages in Western Sichuan (China), resulting in new observations relevant for the understanding of Tangut grammar. In this paper, I intend to present morphosyntactic evidence pointing to the Tangut language’s membership within the Horpa taxon, located within the larger Gyalrongic group of the Qiangic branch of Sino-Tibetan. Tangut exclusively shares with Horpa languages cognates that are far too peculiar to be the result of mere chance. By successively considering the verbal, nominal, and postpositional domains, the present paper highlights evidence that links Tangut to Horpa, while proposing new paths to the understanding of grammatical categories of Tangut proper, such as orientational/aspectual preverbs.1
Precision feeding for optimizing poultry production
Authors: Kidd M.T. , Tillman P.B. , Tillman N.S. , Chrystal P.
Published: September 2023

Consumable poultry from the broiler chicken sector represents a highly complex production and processing supply chain system, yet poultry products are highly versatile, healthy, and affordable for consumers on a global scale. However, the accessibility of broilers to many in developing countries is insufficient to meet daily protein needs. As such, broiler chicken production markets will increase in the foreseeable future in the Americas due to available corn and soybean meal, and in developing countries where protein consumption falls below consumer needs. Feed represents the highest variable costs in broiler chicken production. Broiler diet balanced protein supply differs among producers geographically which is primarily dependent on soybean meal availability and price. In this review, dietary protein supply in terms of feed grade amino acids is discussed. Moreover, broiler diet formulation matrices on a dynamic versus static template are also discussed. In doing so, efficiency and profitability can be gleaned from optimizing the ingredient and nutrient matrices for the overall business as ingredient nutrient compositions and price vary via equations and models, respectively.
Fusion pore dynamics of large secretory vesicles define a distinct mechanism of exocytosis
Authors: Biton Tom , Scher Nadav , Carmon Shari , Elbaz-Alon Yael , Schejter Eyal D. , Shilo Ben-Zion , Avinoam Ori
Published: September 2023

Exocrine cells utilize large secretory vesicles (LSVs) up to 10 μm in diameter. LSVs fuse with the apical surface, often recruiting actomyosin to extrude their content through dynamic fusion pores. The molecular mechanism regulating pore dynamics remains largely uncharacterized. We observe that the fusion pores of LSVs in the Drosophila larval salivary glands expand, stabilize, and constrict. Arp2/3 is essential for pore expansion and stabilization, while myosin II is essential for pore constriction. We identify several Bin-Amphiphysin-Rvs (BAR) homology domain proteins that regulate fusion pore expansion and stabilization. We show that the I-BAR protein Missing-in-Metastasis (MIM) localizes to the fusion site and is essential for pore expansion and stabilization. The MIM I-BAR domain is essential but not sufficient for localization and function. We conclude that MIM acts in concert with actin, myosin II, and additional BAR-domain proteins to control fusion pore dynamics, mediating a distinct mode of exocytosis, which facilitates actomyosin-dependent content release that maintains apical membrane homeostasis during secretion.
δ-Catenin controls astrocyte morphogenesis via layer-specific astrocyte–neuron cadherin interactions
Authors: Tan Christabel Xin , Bindu Dhanesh Sivadasan , Hardin Evelyn J. , Sakers Kristina , Baumert Ryan , Ramirez Juan J. , Savage Justin T. , Eroglu Cagla
Published: September 2023

Astrocytes control the formation of specific synaptic circuits via cell adhesion and secreted molecules. Astrocyte synaptogenic functions are dependent on the establishment of their complex morphology. However, it is unknown if distinct neuronal cues differentially regulate astrocyte morphogenesis. δ-Catenin was previously thought to be a neuron-specific protein that regulates dendrite morphology. We found δ-catenin is also highly expressed by astrocytes and required both in astrocytes and neurons for astrocyte morphogenesis. δ-Catenin is hypothesized to mediate transcellular interactions through the cadherin family of cell adhesion proteins. We used structural modeling and biochemical analyses to reveal that δ-catenin interacts with the N-cadherin juxtamembrane domain to promote N-cadherin surface expression. An autism-linked δ-catenin point mutation impaired N-cadherin cell surface expression and reduced astrocyte complexity. In the developing mouse cortex, only lower-layer cortical neurons express N-cadherin. Remarkably, when we silenced astrocytic N-cadherin throughout the cortex, only lower-layer astrocyte morphology was disrupted. These findings show that δ-catenin controls astrocyte–neuron cadherin interactions that regulate layer-specific astrocyte morphogenesis.
Spinning black holes with axion hair
Authors: Burrage Clare , Fernandes Pedro G S , Brito Richard , Cardoso Vitor
Published: September 2023

In this work we construct and analyze non-perturbative stationary and axially-symmetric black hole solutions in general relativity coupled to an electromagnetic and an axion field. The axion field is coupled to the electromagnetic field, which leads to hairy solutions in the presence of an electric charge and rotation. We investigate the existence and characteristics of these solutions for different values of the spin, charge and coupling constant. Our analysis shows the presence of violations of the Kerr–Newman bound, solutions with large positive and negative values of the gyromagnetic ratio, and the existence of multiple branches of solutions with distinct properties, demonstrating that black hole uniqueness does not hold in this scenario. The code used in this study ispublicly available, providing a valuable tool for further research on this model.
From disformal electrodynamics to exotic spacetime singularities
Authors: Bittencourt Eduardo , Fernandes Ricardo , Goulart Érico , Ottoni José Eloy
Published: September 2023

We study different types of spacetime singularities which emerge in the context of disformal electrodynamics. The latter is characterized by transformations of the background metric which preserve regular (non-null) solutions of Maxwell equations in vacuum. Restricting ourselves to the case of electrostatic fields created by charged point particles along a line, we show that exotic types of singularities arise.
Sparse Bayesian inference with regularized Gaussian distributions
*
Authors: Everink Jasper M , Dong Yiqiu , Andersen Martin S
Published: September 2023

Regularization is a common tool in variational inverse problems to impose assumptions on the parameters of the problem. One such assumption is sparsity, which is commonly promoted using lasso and total variation-like regularization. Although the solutions to many such regularized inverse problems can be considered as points of maximum probability of well-chosen posterior distributions, samples from these distributions are generally not sparse. In this paper, we present a framework for implicitly defining a probability distribution that combines the effects of sparsity imposing regularization with Gaussian distributions. Unlike continuous distributions, these implicit distributions can assign positive probability to sparse vectors. We study these regularized distributions for various regularization functions including total variation regularization and piecewise linear convex functions. We apply the developed theory to uncertainty quantification for Bayesian linear inverse problems and derive a Gibbs sampler for a Bayesian hierarchical model. To illustrate the difference between our sparsity-inducing framework and continuous distributions, we apply our framework to small-scale deblurring and computed tomography examples.
Bursts of polarised single photons from atom-cavity sources
Authors: Ernst Jan Ole , Alvarez Juan Rafael , Barrett Thomas D , Kuhn Axel
Published: September 2023

Photonic qubits play an instrumental role in the development of advanced quantum technologies, including quantum networking, boson sampling and measurement based quantum computing. A promising framework for the deterministic production of indistinguishable single photons is an atomic emitter coupled to a single mode of a high finesse optical cavity. Polarisation control is an important cornerstone, particularly when the polarisation defines the state of a quantum bit. Here, we propose a scheme for producing bursts of polarised single photons by coupling a generalised atomic emitter to an optical cavity, exploiting a particular choice of quantisation axis. In connection with two re-preparation methods, simulations predict ten-photon bursts coincidence count rates on the order of 1 kHz with single

87

R
b

atoms trapped in a state of the art optical cavity. This paves the way for novel n-photon experiments with atom-cavity sources.
Spatiotemporal evolution of electrical conductivity in current-limiting-fuse arc
Authors: Inada Yuki , Fukai Yusuke , Takayasu Naoki , Nakano Yusuke , Zen Shungo , Ohnishi Wataru , Yamano Yasushi , Maeyama Mitsuaki , Kodama Naoto
Published: September 2023

To improve the interruption capacity of a current-limiting fuse, a detailed diagnosis of the spatial electrical conductivity distribution inside the fuse arc under the current limiting phase around current zero is required, because this distribution determines the distribution of transient recovery voltage inside the fuse. However, well-established methodologies applicable to fuse arcs are lacking, so the spatial distribution remains unknown. This study presents a borescope-integrated spectroscopic system that simultaneously obtains single-shot recordings of the axial distributions of the electron density and arc temperature in the fuse arc just before extinction. Combining the electron densities and arc temperatures, we can identify the fuse arc composition and hence calculate the axial electrical conductivity distribution under the first Chapman–Enskog approximation. The electrical conductivity provided by this systematic methodology includes no large uncertainties, thus demonstrating its superiority against previous estimation methods of the electrical conductivity.
Unipolar carrier multiplication high-gain and low-noise AlGaN ultraviolet avalanche photodiode with periodically stacked structure
Authors: Cao Jiying , Wang Jin , You Haifan , Shao Pengfei , Guo Hui , Xue Junjun , Cai Qing , Chen Dunjun
Published: September 2023

Highly sensitive avalanche photodetector (APD) has become a promising candidate for detecting extremely weak target signals. However, the impact ionization multiplication simultaneously triggered by electrons and holes will lead to large excess noise, thus significantly influencing device avalanche performance. Herein, we propose a distinctive AlGaN-based ultraviolet avalanche photodiode with AlN/Al0.2Ga0.8N periodically stacked multiplication region. The higher effective masses and density of states in valence band renders holes limited in the quantum-well region, where thermalization plays a dominant role during carrier transport process. On the contrary, in the atomic-scale AlN/AlGaN stacked structure with a periodic thickness of 10 nm, the electron mutualization motion is conductive to electron obtaining sufficient energy to induce impact ionization. Hence, the mechanism of unipolar carrier induced avalanche multiplication effectively reduces device noise and improving multiplication gain. Meanwhile, the high electric field intensity and tilted energy band in the AlGaN/AlN periodically stacked region significantly contribute to the carrier impact ionization. Consequently, the device achieves a superior avalanche gain of more than 105 at 74 V reverse bias. It is envisioned that the unipolar carrier triggering avalanche events offers a viable route to build high-performance APDs.
On the electronic and spin-valley coupling of vanadium doped MoS2(1−
x
)Se2x
monolayers
Authors: Maity Dipak , Sharma Rahul , Sahoo Krishna Rani , Panda Janmey Jay , Lal Ashique , Puthirath Anand B , Ajayan Pulickel M , Narayanan Tharangattu N
Published: September 2023

Monolayers of MoS2 with tunable bandgap and valley positions are highly demanding for their applications in opto-spintronics. Herein, selenium (Se) and vanadium (V) co-doped MoS2 monolayers (vanadium doped MoS2(1−x)Se2x
(V-MoSSe)) are developed and showed their variations in the electronic and optical properties with dopant content. Vanadium gets substitutionally (in place of Mo) doped within the MoS2 lattice while selenium doped in place of sulfur, as shown by a detailed microstructure and spectroscopy analyses. The bandgap tunability with selenium doping can be achieved while valley shift is occurred due to the doping of vanadium. Chemical vapor deposition assisted grown MoS2 (also selenium doped MoS2 as shown here) is known for its n-type transport behavior while vanadium doping is found to be changing its nature to p-doping. Chirality dependent photoexcitation studies indicate a room temperature valley splitting in V-MoSSe (∼8 meV), where such a valley splitting is verified using density functional theory based calculations.
Efficient channel attention residual learning for the time-series fault diagnosis of wind turbine gearboxes
Authors: Du Wenliao , Guo Zhen , Gong Xiaoyun , Pu Ziqiang , Li Chuan
Published: September 2023

Due to harsh and variable working conditions, the wind turbine gearbox may be damaged during the operation, resulting in an extended downtime with reduced productivity and economic loss. This calls for efficient fault diagnostics for the wind turbine gearboxes. Commonly-used diagnostics based on classical deep learning networks cannot guarantee good performance with time series signals due to the weakness of feature extraction. For this reason, an efficient channel attention residual learning approach is proposed to enhance the feature extraction and fault diagnosis for wind turbine gearboxes, leading to the development of a channel attention residual network (CAResNet). The collected time series signals are directly employed as the input. The efficient channel attention is embedded into the residual network to capture features and improve fault diagnosis capability. Experiments are carried out on a real wind turbine gearbox. The results showed that the average diagnostic accuracy of the CAResNet model was 94.41%. CAResNet has better diagnostic accuracy than other methods proposed in this paper.
Machine learning-enabled thickness estimation of thin coatings on carbon fibre composites using microwaves
Authors: Li Zhen , Meng Zhaozong , Liu Jian , Soutis Constantinos , Gibson Andrew
Published: September 2023

Accurate thickness measurement of thin coatings (typically 50–500 μm) on carbon fibre-reinforced polymer composites is a major challenge in the manufacturing and maintenance processes of modern aircraft. Different from the conventional material-dependent technique for prediction, a machine learning-enabled strategy with an artificial neural network configuration is used with no requirement of prior knowledge of the type of coating or substrate under test. In the test, an open microwave cavity resonator sensor is directly placed on a coated composite, and any variation of the coating material, coating thickness and conductivity of the composite alters the resonance frequency. Principal component analysis is employed in the signal pre-processing for the dimensionality reduction of the raw measurement data. In terms of the root-mean-square error, the maximum value for the calibration approach is approximately 15 μm and that for the machine learning-based approach is 12 μm. The sensor system developed enables real-time on-site assessment of coated composite structures and thus offers a new approach for non-destructive evaluation 4.0 with improved efficiency, accuracy and automation.
GNSS/MEMS IMU vehicle integrated navigation algorithm constrained by displacement vectors in urban environment
Authors: Feng Yihang , Huang Guanwen , Jing Ce , Li Xin , Li Zhenhong
Published: September 2023

The global navigation satellite system (GNSS) and a micro-electro-mechanical system inertial measurement unit (MEMS IMU) can be integrated to form a robust navigation system, providing continuous and accurate location information on dynamic vehicles. However, the performance of a GNSS/MEMS IMU integrated navigation system is easily affected by the accuracy of measurement noise matrix, which is significantly reduced in the urban environment. The adaptive Kalman filter can improve the measurement noise matrix reliability by constructing robust equivalent weight factors; however, GNSS observations are easily misjudged as exception sources that can deteriorate the filter stability. To address these problems, a novel integrated algorithm with a displacement vector constraint is proposed based on the kinematic characteristics of vehicles, which are considered as judgment factors. In this case, the measurement noise can be adjusted accordingly only when the GNSS observations are judged as abnormal. In this study, two types of vehicle navigation experiments were conducted: a low-speed wheeled robot in a campus environment and a dynamic vehicle in an actual urban environment. The experimental results showed that the three-dimensional navigation accuracy was improved by 47% and 55% compared with the conventional algorithm under the two different environments, respectively.
Improving the optoelectronic properties of monolayer MoS2 field effect transistor through dielectric engineering
Authors: Vrinda Narayanan P , Majumder Sudipta , Gokul M A , Taneja Chetna , Kumar G V Pavan , Rahman Atikur
Published: September 2023

The reduced dielectric screening in atomically thin two-dimensional materials makes them very sensitive to the surrounding environment, which can be modulated to tune their optoelectronic properties. In this study, we significantly improved the optoelectronic properties of monolayer MoS2 by varying the surrounding environment using different liquid dielectrics, each with a specific dielectric constant ranging from 1.89 to 18. Liquid mediums offer the possibility of environment tunability on the same device. For a back-gated field effect transistor, the field effect mobility exhibited more than two-order enhancement when exposed to a high dielectric constant medium. Further investigation into the effect of the dielectric environment on the optoelectronic properties demonstrated a variation in photoresponse relaxation time with the dielectric medium. The rise and decay times were observed to increase and decrease, respectively, with an increase in the dielectric constant of the medium. These results can be attributed to the dielectric screening provided by the surrounding medium, which strongly modifies the charged impurity scattering, the band gap, and defect levels of monolayer MoS2. These findings have important implications for the design of biological and chemical sensors, particularly those operating in a liquid environment. By leveraging the tunability of the dielectric medium, we can optimize the performance of such sensors and enhance their detection capabilities.
Bilateral sidewall engineering Si1–x
Ge
x
iTFET for low power display application
*
Authors: Lin Jyi-Tsong , Chu Chun-Ju
Published: September 2023

In this work, we demonstrate the performance enhancement of bottom-gated inductive line-tunneling TFET (iTFET) through the integration of bilateral sidewall engineering with SiGe mole fraction variation, considering the feasibility of the fabrication process. We also employ a metal-semiconductor interface for carrier induction to improve the I
ON, resulting in a lower subthreshold swing average (S.S
avg). Using Sentaurus TCAD simulations, we show that the dominant current mechanism is line tunneling, and the hump effect is mitigated by using SiGe with different mole fractions on the sidewalls. Compared to conventional tunnel field-effect transistors, which require at least three doping processes and annealing, the proposed device requires only one doping process and utilizes the metal-semiconductor interface for carrier induction, significantly reducing the fabrication cost and thermal budget. These measurement based simulations show that the S.S
avg is improved to 21.5 mV dec−1 with an I
ON/I
OFF ratio of 106 at V
D = 0.2 V. This is the first time that a TFT with a subthreshold swing of less than 60 mV dec−1 has been proposed, so it will save much more power in the future and displays with high energy efficiency can be realized and widely used in IoT applications.
Spin–orbit torque on nuclear spins exerted by a spin accumulation via hyperfine interactions
Authors: Cahaya Adam B , Leon Alejandro O , Fauzi Mohammad H
Published: September 2023

Spin-transfer and spin–orbit torques allow controlling magnetic degrees of freedom in various materials and devices. However, while the transfer of angular momenta between electrons has been widely studied, the contribution of nuclear spins has yet to be explored further. This article demonstrates that the hyperfine coupling, which consists of Fermi contact and dipolar interactions, can mediate the application of spin–orbit torques acting on nuclear spins. Our starting point is a sizable nuclear spin in a metal with electronic spin accumulation. Then, via the hyperfine interactions, the nuclear spin modifies the an electronic spin density. The reactions to the equilibrium and nonequilibrium components of the spin density is a torque on the nucleus with field-like and damping-like components, respectively. This nuclear
spin–orbit
torque is a step toward stabilizing and controlling nuclear magnetic momenta, in magnitude and direction, and realizing nuclear spintronics.
Realizing high efficiency and luminance in green, yellow and blue organic light emitting diode by deoxyribonucleic acid
Authors: Song Jiayi , Guan Yunxia , Wang Cheng , Bao Xi , Li Wanjiao , Peng Keao , Xu Shuang , Chen Lijia , Niu Lianbin
Published: September 2023

Although the effect of the electron blocking layer (EBL) material, deoxyribonucleic acid (DNA), on the electroluminescence (EL) performance of organic light-emitting diodes (OLEDs) has been studied, the process of DNA regulation of exciton recombination region within the device is still unclear. Herein, devices with and without EBL were fabricated using different DNA spin-coating speeds, and the photoelectric performance of device were measured. By using DNA compounded with cetyltrimethyl ammonium (CTMA) as the EBL and hole buffer layer, so-called BioLEDs. The DNA-based green Alq3 BioLEDs achieve higher luminance (39 000 cd m−2) and higher current efficiency (8.4 cd A−1), which are increased by 49% and 54%, respectively, compared to the reference OLEDs without the addition of DNA. Similarly, the maximum luminance and efficiency of yellow Rubrene BioLEDs is increased by 64% (from 12 120 to 19 820 cd m−2) and 74% (from 1.36 to 2.36 cd A−1), the luminance and efficiency of blue TCTA BioLEDs is increased by 101% and 245%. Specifically, we found that as the thickness of DNA-CTMA increases, the exciton recombination region moves towards the interface between the emitting layer (EML) and the hole transport layer (HTL). By better confining excitons within the EML, the current efficiency of the BioLEDs is effectively improved. Accordingly, we provide a possible idea for achieve high performance DNA-based BioLEDs by adding DNA-CTMA EBL and hole buffer layers. Meanwhile, as the DNA thickness increases, the exciton recombination region moves towards the EML/HTL interface, thereby enhancing the efficiency of the DNA-based BioLEDs.
Fe3O4 nanoparticles anchored on carbon nanotubes as high-performance anodes for asymmetric supercapacitors
Authors: Gong S H , Kuai J , Wang J D , Liu F , Wu J F , Wang X C , Cheng J P
Published: September 2023

Fe3O4/CNT composites are synthesized with ethylene glycol as solvent by a one-step solvothermal method and used as anode materials for asymmetric supercapacitors (ASC). An appropriate amount of water in ethylene glycol can accelerate the formation of Fe3O4 and reduce the average size of Fe3O4 to around 20 nm. However, spherical Fe3O4 particles larger than 100 nm will form in pure ethylene glycol for long reaction time. The Fe3O4/CNT composite with small Fe3O4 nanoparticles exhibits a high specific surface area, promoted electron transfer ability, as well as a high utilization rate of active materials. The optimized electrode shows a high specific capacity of 689 C g−1 at 1 A g−1, and remains 443 C g−1 at 10 A g−1. The inferior long-term cycling stability is due to the phase transition of Fe3O4 and a reductive effect to form metallic Fe. An ASC using Fe3O4/CNT and NiCoO2/C composites as anode and cathode, respectively, delivers a high energy density of 58.1 Wh kg−1 at a power density of 1007 W kg−1 in a voltage window of 1.67 V and has a capacity retention of 63% after 5000 cycles. The self-discharge behavior of the ASC is also investigated.
QS-ADN: quasi-supervised artifact disentanglement network for low-dose CT image denoising by local similarity among unpaired data
Authors: Ruan Yuhui , Yuan Qiao , Niu Chuang , Li Chen , Yao Yudong , Wang Ge , Teng Yueyang
Published: September 2023

Deep learning has been successfully applied to low-dose CT (LDCT) image denoising for reducing potential radiation risk. However, the widely reported supervised LDCT denoising networks require a training set of paired images, which is expensive to obtain and cannot be perfectly simulated. Unsupervised learning utilizes unpaired data and is highly desirable for LDCT denoising. As an example, an artifact disentanglement network (ADN) relies on unpaired images and obviates the need for supervision but the results of artifact reduction are not as good as those through supervised learning. An important observation is that there is often hidden similarity among unpaired data that can be utilized. This paper introduces a new learning mode, called quasi-supervised learning, to empower ADN for LDCT image denoising. For every LDCT image, the best matched image is first found from an unpaired normal-dose CT (NDCT) dataset. Then, the matched pairs and the corresponding matching degree as prior information are used to construct and train our ADN-type network for LDCT denoising. The proposed method is different from (but compatible with) supervised and semi-supervised learning modes and can be easily implemented by modifying existing networks. The experimental results show that the method is competitive with state-of-the-art methods in terms of noise suppression and contextual fidelity. The code and working dataset are publicly available at https://github.com/ruanyuhui/ADN-QSDL.git.
Streamer-induced kinetics of excited states in pure N2: I. Propagation velocity,
E/N
and vibrational distributions of N2(C 3Πu
) and N 2+
(B 2Σu+
) states
Authors: Bílek Petr , Dias Tiago Cunha , Prukner Václav , Hoffer Petr , Guerra Vasco , Šimek Milan
Published: September 2023

The emission spectra of a streamer discharge in pure nitrogen provide an important tool for investigating the fundamental kinetics of excited electronic states of N2 and benchmark data for validating advanced kinetic schemes for numerical models. In this work, we characterize a streamer monofilament developed in a dielectric barrier discharge configuration, including electrical characteristics, time-resolved images and N2/N

2
+

emission spectra, all acquired with nanosecond temporal resolution. Time-resolved images and emission characteristics provide clear evidence of the formation of a cathode-directed streamer and allow determining the streamer propagation velocity and the typical

E

/

N

values using the intensity ratio of nitrogen spectral bands in the center of the discharge gap. We also measure the vibrational distributions of the N2(C

3

Π

u

,

v
=

 0–4) and N

2
+

(B

2

Σ

u

+

,

v
=

 0–2) states. The population of N2(C

3

Π

u

,

v
=

 0–4) state, initially formed by energetic electrons in the streamer head, changes later significantly due to the decrease in the mean energy and concentration of the streamer channel electrons. After a few tens of nanoseconds, the electron-impact excitation rate of N2(C

3

Π

u

) becomes negligible compared to its population by the N2(

A

3

Σ

u

+

) + N2(

A

3

Σ

u

+

) pooling. The experimental findings are supported and consistent with the 0D state-to-state kinetic model results and reveal the participation of high vibrational levels of N2(

A

3

Σ

u

+

) in the pooling reactions.
Plasma surface ionization wave interactions with single channels
Authors: Morsell Joshua , Trosan Duncan , Stapelmann Katharina , Shannon Steven
Published: September 2023

The study of plasma surface ionization waves (SIWs) in recent years has primarily focused on planar surfaces and periodic two dimensional structures. In application, substrates are likely to have non-planar morphology such as cracks, pores, and steps. Additionally, targets for the applications of medicine or catalysis may have targets with heterogeneous composition. This classification of targets are brought under the umbrella of complex interfaces. In this work, plasma SIWs were incident on a complex target consisting of a single channel cut into glass slides. The SIW velocities for the in-channel portion of the wave and radially propagating portion of the wave were tracked. It was found that surface wave velocities are not significantly affected by channel geometry, but primarily increase with pulse energy. A third propagation direction for the SIW is characterized in the azimuthal direction relative to the radial portion of the wave. Channel geometry is found to greatly effect the area treated by the plasma but not the propagation velocity of the surface wave. Surface wave morphology and the impact on application is also discussed. A simple model was introduced to understand the mechanisms behind SIW escape from a channel. It was found that the ratio of pulse energy to a geometry dependent minimum energy can predict the escape angle of a SIW from single channels.
Orientation texturing and static magnetic response of multi-core particle containing limited number of superparamagnetic nanocores
Authors: Solovyova A Yu , Sokolsky S A , Ivanov A O , Elfimova E A
Published: September 2023

In this paper, we study the orientational texturing and static magnetization of a small multi-core particle (MCP) that includes a few immobilized superparamagnetic particles (SPPs). We focus on the consideration of the MCPs containing 7 and 8 SPPs, which are located randomly or at the nodes of a simple cubic lattice. The results are obtained using Monte Carlo computer simulations. It is shown that intensive dipole–dipole interaction leads to the formation of an orientational texturing of the SPP’s magnetic moments, which strongly depends on the location of the SPPs inside the MCP. The magnetization laws of MCPs are compared with the continuous medium magnetostatics. For strongly interacting SPPs there is a big difference between the simulation results for the magnetization of the MCPs with cubic structure and the magnetization of continuous system of SPPs located in simple cubic lattice. The magnetization of the MCP for each specific random location of the SPPs also differs from the magnetization of continuous media of SPP gas, however, the average value of the MCP magnetization coincides with the continuous media magnetostatics.
The role of plasma–atom and molecule interactions on power & particle balance during detachment on the MAST Upgrade Super-X divertor
Authors: Verhaegh K. , Lipschultz B. , Harrison J.R. , Federici F. , Moulton D. , Lonigro N. , Kobussen S.P. , O’Mullane M. , Osborne N. , Ryan P. , Wijkamp T. , Kool B. , Rose E. , Theiler C. , Thornton A.J. ,   the MAST Upgrade Team
Published: September 2023

This paper shows first quantitative analysis of the detachment processes in the MAST Upgrade Super-X divertor (SXD). We identify an unprecedented impact of plasma-molecular interactions involving molecular ions (likely

D
2
+

), resulting in strong ion sinks (Molecular Activated Recombination—MAR), leading to a reduction of ion target flux. The MAR ion sinks exceed the divertor ion sources before electron-ion recombination (EIR) starts to occur, suggesting that significant ionisation occurs outside of the divertor chamber. In the EIR region,

T
e

≪
0.2

 eV is observed and MAR remains significant in these deep detached phases. The total ion sink strength demonstrates the capability for particle (ion) exhaust in the Super-X Configuration. Molecular Activated Dissociation is the dominant volumetric neutral atom creation process can lead to an electron cooling of 20% of

P

S
O
L

. The measured total radiative power losses in the divertor chamber are consistent with inferred hydrogenic radiative power losses. This suggests that intrinsic divertor impurity radiation, despite the carbon walls, is minor in the divertor chamber. This contrasts previous TCV results, which may be associated with enhanced plasma-neutral interactions and reduced chemical erosion in the detached, tightly baffled SXD. The above observations have also been observed in higher heat flux (narrower SOL width) type I ELMy H-mode discharges. This provides evidence that the characterisation in this paper may be general.
Microstructural Influence on Fracture Toughness of IF Steel and DP Steel
Authors: Sunilkumar M R , Schmidova E. , Klejch F.
Published: September 2023

Interstitial free steels (IF) and Dual-phase (DP) steels are widely used in the automotive industry, their specific application is driven by requirements to optimize the strength-to-weight ratio. Utilizing the full capacity of their plasticity and strain hardenability requires an assessment of edge fracture susceptibility and flangeability. In this work, the ability of the mentioned steels to spreading of deformation along initiated cracks is evaluated by structural and fractographic analyzes. Microstructural restrictions of plasticity are correlated with fracture toughness results, adopting the essential work of fracture (EWF) methodology. Crystallographic analyzes (EBSD) are focused on the role of anisotropy and the deformation texture evolution, affecting the development of plasticity and thus the energy consumption to the fracture.
Effects of etchant stirring on the surface quality of the metallography sample
Authors: Ambrož O , Čermák J , Jozefovič P , Mikmeková Š
Published: September 2023

Despite its predominantly empirical nature, metallographic etching remains an important sample preparation method that enables microstructural characterization. The poor repeatability is due to the ignorance of etching mechanisms and the human factor, which is mainly associated with the conventional approach. This approach is most commonly practiced by manual immersion of the sample in the etchant. The solution should be gently stirred so that reaction products do not settle on the surface and uneven etching does not occur. Often, stirring is provided by the sample itself or by a magnetic bar. In terms of spatial orientation, etching with the polished surface facing upwards allows the surface to be observed during the process. Some authors recommend etching with the polished surface downwards to minimize the deposition of reaction products. In some cases, a vertical orientation of the sample is recommended to reduce pitting. In this paper, the effect of the etchant stirring method on the surface quality of a metallographic structural steel specimen will be presented. In addition to different etchant stirring methods, different spatial orientations of the sample will also be investigated. To ensure better repeatability and accurate etching time, the samples will be etched using our automated apparatus. The resulting surface of the samples will be analysed using light optical microscopy (LOM) and confocal laser scanning microscopy (CLSM). The development of more reproducible etching methods is essential to obtain accurate microstructure information without artifacts and for advanced quantitative image analysis using deep learning.
Effect of tool temperature and dwell time in the tool for press hardening on the mechanical properties of modern high-strength steel with 3% Mn
Authors: Janda T , Jirková H , Leták R , Skrivanova N , Kučerová L , Holá M
Published: September 2023

The production of sheet safety parts for car bodies is currently carried out using press hardening technology. This technology enables the creation of complex-shaped profiles even from high-strength steels without a significant spring-back effect. In combination with modern high-strength steels, which have retained austenite in their structure, it is possible to achieve high ultimate strength and ductility values. As a result, these parts are used in bodywork areas with high energy absorption requirements during impact. To achieve the required mechanical properties, suitable processing parameters must be selected. High-strength steel with 0.2%C, 3%Mn and 2%Al was used for the experiment. Press-hardening was carried out in a tool fixed in a hydraulic press and can be heated up to temperatures around 450 °C. Different tool temperatures of room temperature and 425 °C were tested and different holding times in the tool from 1 s to 600 s. After hardening in a tool at RT, the ultimate strength of about 1400 MPa with a ductility of 18 % was obtained. But quenching and holding in the preheated tool caused the ductility to increase to 28% with a drop in ultimate strength to 1050 MPa.
Overview of the International Scientific Conference on Advances in Applied Physics and Mathematics 2023 (AAPM-2023)
Authors: Sultanov T Z , Shomirzaev M Kh , Astanakulov K D , Borotov A N
Published: September 2023

The overview describes the main directions and results of the International Scientific Conference on Advances in Applied Physics and Mathematics held in Tashkent on 10-12 April 2023. It gives the details about the participants and the proceedings. The Conference AAPM-2023 provided a remarkable opportunity for the academic and industrial communities to address new challenges and share solutions, and discuss future research directions in the field of applied physics and mathematics.

List of Programme Committee is available in this pdf.
Effects of pulsed laser hardening of cylindrical surfaces on fatigue behavior
Authors: Alisin Valery
Published: September 2023

The issues of the of laser hardening of the plain bearing effects on the fatigue strength of the crankshaft neck journal are discussed in this article. The crankshaft destruction of the crankshaft leads to catastrophic consequences, especially for heavy diesel engines. The article substantiates the assertion of a decrease in the fatigue strength of steels after pulsed laser hardening treatment of the friction surface to increase the wear resistance of a plain bearing. The process of formation of a surface hard layer of steel and the formation of dimple-shaped stress concentrators on it after interaction with a laser pulse is studied. Factors affecting the fatigue behavior of materials are analyzed. Particular attention is paid to the formation of a residual stress state in the surface layer and the role of surface defects on the fatigue behavior of steel. The assumption about the possibility of reducing the decrease in fatigue strength by optimizing the technological parameters of laser processing is substantiated. On the basis of the study, it is proposed to limit the energy of the laser pulse, preventing the surface from melting.
Determination of the local refraction coefficient in Cuban lateritic mineral deposits
Authors: Ojeda Pardo F R , Belette Fuentes O , Quiroz Cabascango V E , Mosquera Urbano A P , Reyes Céspedes E
Published: September 2023

Much work has been done related to the characteristics of terrestrial refraction. However, very few have referred to the fluctuations of the refractive coefficient in the lower atmosphere in Cuban lateritic deposits. The objective of this research is to determine a local refraction coefficient in different climatic conditions and time of day, to increase the precision of the mineral volume calculation and to know its behavior and to analyze the influence of local refraction coefficient variations on the trigonometric leveling. The method of reciprocal simultaneous measurements of the vertical angle was applied to minimize the influence of the refractive coefficient and assess the errors committed. As results, a refraction coefficient of 0,17 was obtained, different from the 0,14 that is currently used, and that the Gaussian refraction coefficient +0,13 is not adequate to describe the refraction effects in the lower atmosphere. In conclusion, these results can be useful to better evaluate the role of refraction in topographic surveys at 1,5 m from the visual ray of the ground, in lateritic deposits on slopes greater than 20 %. The experiment on refraction showed a range of variation of KL between 0,134-0,179 near the ground on sunny days. This equates to vertical temperature gradients are 0,064-0,144 K/m during the day and 0,054 K/m after sunset.
Microstructure, magnetoresistivity and carrier mobility of HTSC-YBCO tape with pinning centers generated by electron irradiation
Authors: Ibragimova E M , Mussaeva M A , Shodiev A A , Iskandarov N E , Nazarov K T
Published: September 2023

Artificial pinning center lattice formed in HTSC both chemically and by irradiation is believed to increase critical current and field although Abrikosov vortex core is in the normal state. The paper presents SEM-EDS, XRD and Hall effect (80-300 K at magnetic field 0.55 Tesla) data in YBCO microfilm on 276-steel tape with metal coating exposed to 5 MeV electrons (1014 cm-2 at 400 nA) in air. No long-living radioisotope was generated. This irradiation resulted in structure modification of microinterfaces YBCO-AgCu, ten times decrease in the magneto-resistance >T
c, increase in the 2nd type phase transition steep. The charge carrier mobility μ decreased by a few orders of value, especially at T <100 K and 280 K, where Cooper pairs and magnons condensate, respectively. Within 80-300 K the tape is in mixed magnetic states of YBCO and steel substrate, thereby providing effective flux pinning by highly correlated non-superconducting state.
Anisotropic scattering of charge carriers in double continuous solid solutions of the niobium-vanadium system
Authors: Kuvandikov O K , Hamrayev N S , Rajabov R M , Hamrayeva N N
Published: September 2023

The article is devoted to the study of anisotropic scattering of charge carriers in double continuous solid solutions of the niobium-vanadium system. It has experimentally investigated the temperature dependence of the Hall coefficient of V, Nb and five continuous solid solutions of V-Nb system at the temperature range 77-1000K. The authors have constructed the concentration dependence of R for the temperature 77K, 300K, 600K and 900K and calculated electronic zone parameters of such samples as concentration of conduction electrons n, Fermi wave vector kf, Fermi velocity vf and Fermi energy Ef using the obtained experimental data on R(T) dependence.
Simulation of natural convection in a solar collector
Authors: Jumaev Jura , Kodirov Jobir , Mirzaev Shavkat
Published: September 2023

The process of natural convection in a flat solar collector, which was designed by the authors, was mathematically modeled using experimental data. Stones were used as storage means. The inclined collector is expressed as a two-dimensional plate for modeling. The initial and boundary conditions were formulated. It was assumed that the flow in this region is laminar. To simulate the flow of natural air convection, a system of non-stationary partial differential equations was chosen based on the laws of conservation of mass, momentum and energy in the Boussinesq approximation. The equations were solved in a dimensionless form using the finite difference method and an explicit scheme. The picture of the temperature fields and the appearance of convection was obtained on the basis of experimental temperature data in the inlet and outlet zones of the collector, as well as on the surface of the heat accumulator during the day. To evaluate the effectiveness of the resulting model an average approximation error (approximation) of 7.7% was established. The results obtained in specific values of the Grashof and Prandtl numbers are presented in the form of graphs.
Mathematical modelling and research of output spectrum of synthesizers based on high-speed DAC for 5G
Authors: Yakimenko K A , Romashov V V , Doktorov A N , Sochneva N A
Published: September 2023

The paper presents a mathematical model of the output signal of high-speed digital-to-analogue converters in special operating modes. This model simulates the output signal of a high-speed digital-to-analogue converters in time and frequency domain for the research of their frequency spectrum. The model consists of nonlinearities which cause undesirable frequency components (spurs) in the output spectrum. These are nonlinearities due to output signal sampling, phase code truncation and amplitude quantization errors. The paper describes PLL+DAC synthesizer which allows reducing the number and level of spurs in output spectrum.
Data augmentation by using gans and image transformation in facial emotion classification
Authors: Huang Hongpei
Published: September 2023

We propose different approach combinations including GANs and image transformation in facial emotion classification especially for FER-2013 dataset. Our goal is not to reach the highest accuracy for this dataset, but to compare and verify the data augmentation effects for several main GAN methods such as Vanilla GAN, CGAN, DCGAN and BiGAN. We used these GAN models to generate fake images and put them to our train dataset. And the data together was through image transformation to train in the CNN model that we designed to perform facial emotion classification. Base on the result when we used some GANs (BiGAN/DCGAN) and image transformation, the accuracy of the model indeed has been improved. The best combination data augmentation approaches in this paper are using image transformation and DCGAN.