bluuebunny/crossref_metadata_2025 huggingface dataset:
Adversarial training of multi-scale channel attention network for enhanced robustness in bearing fault diagnosis
Authors: Peng Haotian , Du Jinsong , Gao Jie , Wang Yu , Wang Wei
Published: February 2024

For bearing fault diagnosis problems in extremely noisy environments, this paper proposes an innovative universal adversarial training method. This method dynamically introduces noise into the training data, adaptively optimizing the model’s robustness. It applies to any neural network without incurring additional computational overhead in the reasoning process. Additionally, we introduce the multi-scale channel attention network (MSCAN). This network employs stacked convolutional kernels of varying sizes to extract features at different scales from the input signal. The incorporation of the channel attention mechanism allocates distinct weights to features of different scales, further enhancing the network’s representational capacity. Moreover, an automated machine learning-based automated tuning approach is employed to optimize the model training process, aiding in improving inference accuracy. Compared to existing designs, MSCAN exhibits exceptional accuracy. Through adversarial training, it maintains a 99.44% accuracy rate on the Case Western Reserve University dataset under strong −3 dB noise conditions. On the Paderborn University dataset at 0 dB, this adversarial training significantly improves the testing accuracy of various models by an average of 36.42%.
A hybrid remaining useful life prediction method for lithium-ion batteries based on transfer learning with CDRSN-BiGRU-AM
Authors: Li Lei , Li Yuanjiang , Zhang Jinglin
Published: February 2024

The prediction of the remaining useful life (RUL) of widely used lithium-ion batteries (LIBs) is of great importance. Existing techniques struggle to balance prediction accuracy with execution time. To achieve accurate RUL prediction quickly, a hybrid RUL prediction method for LIBs has been developed. This method first employs a channel-wise deep residual shrinkage network to adaptively extract features from input data enhancing important information features and suppressing ineffective ones based on the significance of the feature information. Subsequently, a bidirectional gated recurrent unit is used to extract bidirectional temporal features from the processed data, and an attention mechanism is introduced to maximize the extraction of significant temporal mutual information. Finally, a fully connected layer transfer strategy is applied to transition the model from offline training to online prediction, which avoids unstable predictions due to random model initialization and significantly improves the model’s computational efficiency. The simulation results show that the root mean square error of the proposed method did not exceed 1.77% and the mean absolute error did not exceed 1.44% on the NASA dataset. Consequently, the proposed method can achieve accurate online RUL prediction accuracy for LIBs.
Stepwise feature norm network with adaptive weighting for open set cross-domain intelligent fault diagnosis of bearings
Authors: Jia Feng , Wang Yuanfei , Shen Jianjun , Hao Lifei , Jiang Zhaoyu
Published: February 2024

Cross-domain fault diagnosis of bearings has attracted significant attention. However, traditional cross-domain diagnostic methods have the following shortcomings: (1) when the trained model is applied to a new scenario, it leads to severe degradation of the model and a reduction in its generalisation ability. (2) The accuracy of the open-set fault diagnosis is affected by additional faults in the target domain data. To overcome these shortcomings, a stepwise feature norm network with adaptive weighting (SFNAW) is proposed for cross-domain open-set fault diagnosis. In SFNAW, two weight extractors are designed to adaptively calculate the sample weights such that a threshold can be set to mark the additional fault samples of the target domain as unknown faults using these weights. Transferable features are obtained by adaptively increasing the feature norm stepwise to alleviate model degradation and align the source and target domains. Finally, the fault diagnosis knowledge of the source domain is transferred to fault recognition in the target domain. The proposed SFNAW method was verified using two bearing datasets. The results show that the SFNAW can effectively detect additional faults in the target domain and reduce model degradation, thereby improving the fault diagnosis accuracy. Meanwhile, the SFNAW method has a higher accuracy than other traditional methods.
Bismuth sulfide micro flowers decorated nickel foam as a promising electrochemical sensor for quantitative analysis of melamine in bottled milk samples
Authors: Ravipati Manaswini , Singh Pratiksha , Badhulika Sushmee
Published: February 2024

Here, we demonstrate hydrothermally grown bismuth sulfide (Bi2S3) micro flowers decorated nickel foam (NF) for electrochemical detection of melamine in bottled milk samples. The orthorhombic phase of hydrothermally grown Bi2S3 is confirmed by the detailed characterization of x-ray diffraction and its high surface area micro flowers-like morphology is investigated via field emission scanning electron microscope. Furthermore, the surface chemical oxidation state and binding energy of Bi2S3/NF micro flowers is analyzed by x-ray photoelectron spectroscopy studies. The sensor exhibits a wide linear range of detection from 10 ng l−1 to 1 mg l−1 and a superior sensitivity of 3.4 mA cm−2 to melamine using differential pulse voltammetry technique, with a lower limit of detection (7.1 ng l−1). The as-fabricated sensor is highly selective against interfering species of p-phenylenediamine (PPDA), cyanuric acid (CA), aniline, ascorbic acid, glucose (Glu), and calcium ion (Ca2+). Real-time analysis done in milk by the standard addition method shows an excellent recovery percentage of ̴ 98%. The sensor’s electrochemical mechanism studies reveal that the high surface area bismuth sulfide micro flowers surface interacts strongly with melamine molecules through hydrogen bonding and van der Waals forces, resulting in a significant change in the sensor’s electrical properties while 3D skeletal Nickel foam as a substrate provides stability, enhances its catalytic activity by providing a more number /of active sites and facilitates rapid electron transfer. The work presented here confirms Bi2S3/NF as a high-performance electrode that can be used for the detection of other biomolecules used in clinical diagnosis and biomedical research.
Thermal conductivity and structural behavior of confined H2 from molecular dynamics simulation
Authors: Yousefi Farrokh , Farzadian Omid , Shafiee Mehdi
Published: February 2024

In this work, we perform equilibrium molecular dynamics simulation to study the thermal conductivity of hydrogen molecules (H2) under extreme confinement within graphene nanochannel. We analyze the structural behavior of H2 molecules inside the nanochannel and also examine the effect of nanochannel height, the number of H2 molecules, and temperature of the system on the thermal conductivity. Our results reveal that H2 molecules exhibit a strong propensity for absorption onto the nanochannel wall, consequently forming a dense packed layer in close to the wall. This phenomenon significantly impacts the thermal conductivity of the confined system. We made a significant discovery, revealing a strong correlation between the mass density near the nanochannel wall and the thermal conductivity. This finding highlights the crucial role played by the density near the wall in determining the thermal conductivity behavior. Surprisingly, the average thermal conductivity for nanochannels with a height (h) less than 27 Å exhibited an astonishing increase of over 12 times when compared to the bulk. Moreover, we observe that increasing the nanochannel height, while the number of H2 molecules fixed, leads to a notable decrease in thermal conductivity. Furthermore, we investigate the influence of temperature on thermal conductivity. Our simulations demonstrate that higher temperature enhance the thermal conductivity due to increased phonon activity and energy states, facilitating more efficient heat transfer and higher thermal conductivity. To gain deeper insights into the factors affecting thermal conductivity, we explored the phonon density of states. Studying the behavior of hydrogen in confined environments can offer valuable insights into its transport properties and its potential for industrial applications.
Revisiting the Kepler problem with linear drag using the blowup method and normal form theory
Authors: Kristiansen K Uldall
Published: February 2024

In this paper, we revisit the Kepler problem with linear drag. With dissipation, the energy and the angular momentum are both decreasing, but in Margheri et al (2017 Celest. Mech. Dyn. Astron.
127 35–48) it was shown that the eccentricity vector has a well-defined limit in the case of linear drag. This limiting eccentricity vector defines a conserved quantity, and in the present paper, we prove that the corresponding invariant sets are smooth manifolds. These results rely on normal form theory and a blowup transformation, which reveals that the invariant manifolds are (nonhyperbolic) stable sets of (limiting) periodic orbits. Moreover, we identify a separate invariant manifold which corresponds to a zero limiting eccentricity vector. This manifold is obtained as a generalized center manifold over the zero eigenspace of a zero-Hopf point. Finally, we present a detailed blowup analysis, which provides a geometric picture of the dynamics. We believe that our approach and results will have general interest in problems with blowup dynamics, including the Kepler problem with generalized nonlinear drag.
Kresling origami-inspired electromagnetic energy harvester with reversible nonlinearity
Authors: Yin Peilun , Han Hesheng , Tang Lihua , Tan Xing , Guo Muxuan , Xia Cuipeng , Aw Kean Chin
Published: February 2024

This paper presents an electromagnetic energy harvester based on a unique nonlinear Kresling origami-inspired structure. By introducing the equilibrium shift phenomenon, reversible nonlinearity (i.e. mixed softening-hardening behavior) empowers the proposed harvester to work in a broad frequency band, confirmed by both simulation using a dynamic model and experimentation. The prototyped device can produce the open-circuit root mean square (RMS) voltage from 0.09 V to 0.20 V in the reversibly nonlinear response region in (6.19 Hz, 9.63 Hz) and a maximum output power of 0.4956 mW at an optimum load of 18.1 Ω under the excitation of 1.1 g. Moreover, detailed research further reveals that the design parameters of Kresling origami-inspired structure and electrical and mechanical loads influence reversible nonlinearity. Increasing the tip mass and γ
0 in the M2 region of the design map strengthens the softening behavior, and enlarging the electrical load enhances the hardening behavior. The findings from this work deepen the understanding of the nonlinear behavior of Kresling origami, unveils the great potential of origami structure in energy harvesting and offers a new method to realize broadband vibration energy harvesters.
An analytical approach for Yang transform on fractional-order heat and wave equation
Authors: Kapoor Mamta , Kour Simran
Published: February 2024

A novel approach to locate the approximate analytical solutions for non-linear partial differential equations is presented in this paper: the Yang transformation method combined with the Caputo derivative. In the current work, we determine the fractional Heat and Wave equation’s approximate analytical solutions. This current work addresses the Yang transformation approach in addition with the Caputo derivative. The suggested method yields approximately analytical solutions in the form of series with a simple, straightforward mechanics and a proportionality dependent on values of the fractional-order derivative. A few numerical heat equation and wave equation problems are solved to show the usefulness and reliability of the method. The tabular form [tables 7–12] makes the claim that the absolute error decreased as the number of terms in the series increased. It is also confirmed that the results are graphical compatible.
Constraining Palatini gravity with GR-independent equations of state for neutron stars
Authors: Lope-Oter Eva , Wojnar Aneta
Published: February 2024

We demonstrate how to construct GR-independent equations of state for a neutron star from the information available in the literature. We emphasize the importance of using theory-based principles instead of relying solely on astrophysical observables and General Relativity. We propose a set of equations of state based on first microscopic principles, including chiral perturbation theory and perturbation theory in quantum chromodynamics. Interpolation methods are employed with assumptions on the thermodynamic stability and causality in the intermediate region. These equations of state are then used to constrain quadratic Palatini f(ℛ) gravity, indicating that its free parameter can at most lie within the range around -6.47 ≲ β ≲ 1.99 km2. Additionally, we briefly discuss the problem of phase transitions and twin stars.
Constraining primordial black hole masses through f(R) gravity scalarons in Big Bang Nucleosynthesis
Authors: Talukdar Abhijit , Kalita Sanjeev , Das Nirmali , Lahkar Nandita
Published: February 2024

Big Bang Nucleosynthesis (BBN) is a strong probe for constraining new physics including gravitation. f(R) gravity theory is an interesting alternative to general relativity which introduces additional degrees of freedom known as scalarons. In this work we demonstrate the existence of black hole solutions in f(R) gravity and develop a relation between scalaron mass and black hole mass. We have used observed bound on the freezeout temperature to constrain scalaron mass range by modifying the cosmic expansion rate at the BBN epoch. The mass range of primordial black holes (PBHs) which are astrophysical dark matter candidates is deduced. The range of scalaron mass which does not spoil the BBN era is found to be 10-16–104 eV for both relativistic and non-relativistic scalarons. The window 10-16–10-14 eV of scalaron mass obtained from solar system constraint on PPN parameter is compatible with the BBN bound derived in this work. The PBH mass range is obtained as 106–10-14
M
⊙. Scalarons constrained by BBN are also eligible to accommodate axion like dark matter particles. The problem of ultra-light PBHs (M ≤ 10-24
M
⊙) not constrained by the present study of BBN is still open. Estimation of deuterium (D) fraction and relative D+3He abundance in the f(R) gravity scenario shows that the BBN history mimics that of general relativity. While the PBH mass range is eligible for non-baryonic dark matter, the BBN bounded scalarons provide with an independent strong field test of f(R) gravity. The PBH mass range obtained in the study is discussed in relation to future astronomical measurements.
Investigation of renal calculi fragmented tracer particles in lithotripsy model by laser speckle technique
Authors: Balamurugan R , Rathina K
Published: February 2024

We have developed a laser sheet method to evaluate micro-sized fragmented calcium oxalate granular particles created kidney stones suspended in a Newtonian fluid in an in vitro model. These tracer particles are examined by laser optical techniques. An optical setup is configured with a laser sheet to conduct image velocimetry on these calcium oxalate seed particles in the urine environment. The experimental setup involves the application of ultrasonic waves to fragment the calcium oxalate tiny stones of varying sizes and disperse them in random directions in the fluid. The data acquisition process employs double frame-single exposure imaging, which captures images at specified time intervals using a high-resolution CCD camera. This provides information regarding particle displacement and track the flow path within the Newtonian fluid. In addition, the bigger fragmented particles are identified, and their sizes are also measured.
Core ion measurements with collective Thomson scattering for DEMO burn control
Authors: Rasmussen J. , Korsholm S.B.
Published: February 2024

DEMO burn control will require measurements of a range of plasma parameters, but the suite of feasible diagnostics for this purpose is limited. Here we assess the accuracy with which a collective Thomson scattering (CTS) diagnostic can provide key measurements for burn control in the planned European DEMO (EU-DEMO). This is based on estimated signal-to-noise ratios for a conceptual diagnostic design and trial fits to synthetic DEMO CTS spectra. We show that a diagnostic with a single probe- and receiver beam setup will be able to provide simultaneous measurements of core fusion alpha density and ion temperature to mean accuracies better than 5% and 10%, respectively, along with detecting intrinsic toroidal rotation velocities down to within

∼

5

km s−1. Adding a second CTS receiver view furthermore enables inference of the core fuel-ion ratio, allowing discrimination between, e.g. a 50%/50% and 55%/45% D/T mixture, while also providing useful information on the thermalized He content. A DEMO CTS diagnostic would thus be able to monitor fusion alpha densities as well as anomalous transport of fast alphas and heat from the plasma core, quantify plasma rotation for confinement enhancement, and track the core isotope mix for optimum fusion performance. This versatility makes such a diagnostic a potentially valuable tool for real-time burn control on DEMO.
SiCf/SiC composites tolerance to high temperature combustion atmosphere and post ageing mechanical and microstructural characterisation
Authors: Bassi Stefano , Mingazzini Claudio , Leoni Enrico , Scafe’ Matteo , Fabbri Paride , Vignoles Gerard-Louis , Rebillat Francis , Verdy Christophe , Bertrand Pierre
Published: February 2024

This article reports the activities carried out under WP4, coordinated by ENEA, within the CEM-WAVE European project, about experimental study on SiCf/SiC composites tolerance to high temperature combustion atmosphere. Water corrosion phenomena are known to affect mechanical properties of SiC-based CMC, due to the formation of a silica, volatile in certain condition. The study will simulate combustion conditions, aiming at using more environmentally friendly alternatives to methane, such as hydrogen, coke oven gas or biomethane, in steel production. It is essential to determine, in each case, if corrosion happens in active (that means continuous degradation) or passive (silica forms a protective “scale” on the component) regime. Since fibre-to-matrix interface can also be degraded, it is important to determine post-ageing mechanical flexural strength (by 4point bending tests). Water corrosion ageing was performed by means of direct flame exposure. When the oxidizing species becomes CO2, instead of O2, the formation rate of silica passivating layer is expected to be lower than the volatilization rate, and consequently active oxidation results in continuous weight loss. Ageing tests of SiCf/SiC composites were carried out at high temperature in a CO2/H2O/N2 gaseous environment at atmospheric pressure (reference conditions: 1200°C, 10/20/70 v/v). Bending tests up to failure are carried out at room temperature on these aged samples after different exposure times. Relationships are established between the evolution of mechanical properties, the ageing conditions, and the rates of oxidation reactions.
Practical Fatigue Strength Diagrams for Compression Springs Based on the FKM-Guideline “Analytic Strength Assessment for Springs“
Authors: Petrich Martin , Kletzin Ulf
Published: February 2024

Today’s helical compression springs are designed according to DIN EN 13906-1. The fatigue diagrams contained there are outdated and essential influences on fatigue strength are not taken into account. In order to resolve these circumstances, endurable stresses were calculated with the FKM guideline “Analytic Strength Assessment for Springs and Spring Elements”, which was published in 2020. The application of the included safety concept results in characteristic curves for permissible stresses that are conservative with regard to real test data. Therefore, the new fatigue strength diagrams can be used directly for standard applications. This article gives an overview of the method and accompanying experiments. The presented results enable spring designers to design competitive springs in a shorter time and with less testing effort according to the current state of research.
iKonPro®: A software for the probabilistic prediction of rolling contact fatigue
Authors: Escalero Mikel , Olave Mireia , Behnke Karsten , Muñiz-Calvente Miguel
Published: February 2024

This work develops a software for the probabilistic prediction of rolling contact fatigue in multiple-row ball bearings subject to any loads and rotations. iKonPro®, as it has been named, calculates the failure probability of the raceways and the bearing, taking as input the material fatigue properties, contact-load and -angle distributions for discrete load cases, and the subsurface stress responses to different ball loads. The software is based on the determination of ball kinematics and equilibrium, raceways stress states, and local and global failure probabilities. Here, iKonPro® is applied to a wind-turbine pitch bearing and the results demonstrate that it correctly captures the size effect.
Hydrocode numerical modeling of projectile impact on moving aluminum targets
Authors: Kalfountzos Costas D , Bikakis George S E , Theotokoglou Efstathios E
Published: February 2024

This paper deals with the investigation of high velocity normal impacts of a rigid cylindrical projectile on moving aluminum plates. The targets are supported with mixed boundary conditions which permit their rigid body motion in the plane perpendicular to the initial striker’s trajectory with a predetermined initial velocity. A 3D numerical modeling procedure based on the finite difference method is implemented for this problem with the ANSYS AUTODYN hydrocode. The Johnson-Cook plasticity and damage models are used for the aluminum target. The numerical modeling is validated through suitable comparisons with experimental data concerning stationary targets. The effect of striker’s and target’s initial velocities is studied on the projectile’s trajectory and the striker’s energy loss after the full perforation of the target. It is found that the energy loss of the striker’s kinetic energy is higher for relatively higher values of the projectile’s velocity. The striker’s energy loss decreases as the velocity of the target increases. Diagrams of the energy time-histories of the striker-target system are constructed for different initial velocities of the plate and the projectile. It is observed from these diagrams that the internal energy of the plate depends mainly on the plastic work.
Stationary response of the system “Cylindrical shell – viscoelastic filler” to the effect of a moving load
Authors: Teshaev Muhsin , Safarov Ismoil , Ibragimova Dilshoda , Rayimov Doniyor , Akhmedov Sharif
Published: February 2024

The paper considers the stationary response of the system “cylindrical shell - viscoelastic filler” to the action of a moving load. The filler and the shell were assumed to be viscoelastic. Using the principle of analogy of viscoelastic and elastic problems (elastic-viscoelastic analogy), a stationary solution of the action of mobile loads on a shell with a viscoelastic filler is obtained. It is shown that this principle makes it possible to generalize the class of problems obtained for the case of viscoelastic media. Since the viscoelastic filler has damping properties, the inversion integrals have no singularities on the real axis, and the elements of the determinants in integrals become complex since in this problem in the image space, the Lame coefficients are complex and depend on the speed of the load movement, as well as the Fourier transform parameter. Numerical results are obtained, and an analysis is made.
Manufacturing process development for engine construction parts from composite materials by 3D printing
Authors: Firsin A O , Vdovin R A , Goncharov E S , Markanov I D
Published: February 2024

This paper represents the development of the general design algorithm for structures of parts made of composite materials in respect of the additive manufacturing technology. Information on the 3D printing technology by extrusion is provided. Main design stages for production tooling for the “Insert” part, with regard of possibilities and limitations of printing on 3D printers, are described. Roughness analysis of samples, manufactured on the 3D printer from various composite materials, has been carried out.
A method of spraying based on hydrodynamic and ultrasonic influence on the sprayed liquid
Authors: Shalunov Andrey V , Nesterov Viktor A , Genne Dmitriy V
Published: February 2024

The article is devoted to the development of a sprayer based on the method of simultaneous hydrodynamic and ultrasonic influence on the flow of sprayed liquid. The proposed spraying method makes it possible to increase spraying productivity while reducing the size of aerosol droplets. By establishing optimal conditions, with a nozzle diameter of 0.7 mm, an ultrasonic tool diameter of 8 mm and an excess pressure of the sprayed liquid of 0.7 MPa, the atomizer provides a productivity of 9 ml/s and forms an aerosol with droplet sizes D32 = 40 μm. This is primarily due to the establishment of the optimal operating mode and conditions in the cavitation zone, which make it possible to ensure the highest quantitative concentration of cavitation bubbles.
Small-signal simulation applied to calculation of the parameters of nonlinear dynamics processes control systems for DC/DC converters
Authors: Andriyanov A I
Published: February 2024

The article discusses the issues of choosing the control system parameters for pulse-width DC/DC converters with the target-oriented control. This takes into account the nonlinear dynamic processes control system, which is important when constructing power conversion systems with increased requirements for speed. A nonlinear dynamic model of the system is developed taking fully into account the dynamic properties of the control system. A technique for selecting control system parameters based on small-signal modelling is proposed, which greatly simplifies the calculation process. The suggested approach can be applied in developing DC/DC converters of a wide class.
Resident space objects classification by machine learning techniques
Authors: Samorodova Ekaterina
Published: February 2024

In recent years the number of resident space objects in near-Earth space has been increasing drastically, which can lead to a “cascade collisions” effect and other catastrophic consequences. Therefore, it is crucial to monitor resident space objects, maintain and update catalogues on time, including the identification of unknown space objects to estimate their location and potential orbit. It is necessary to perform resident space object identification quickly and accurately to avoid possible satellite collisions resulting in large clouds of uncontrollable space debris fragments. That is why the task of resident space object preliminary classification by TLEs is stated and solved by applying machine learning approaches to achieve a higher classification quality and speed. This issue is a highly imbalanced classification problem, which narrows and specifies the used models. Applying the proposed resident space object classification model to space surveillance systems can decrease the time required for the object identification significantly.
Study of the block and convolutional code decoding efficiency using a turbo code decoder
Authors: Sidorenko Alexander A
Published: February 2024

An urgent task is to correct errors that occur during the transmission and storage of information. To solve this problem, various noise-resistant codes have recently been increasingly used. Turbo codes have the best correcting ability in data transmission channels with a high probability of an erroneous bit. To obtain the necessary characteristics, various combinations of codes and encoding and decoding methods are used. If another block of information bits is added to the codeword of a systematic block or systematic convolutional code, then it will be possible to implement decoding of such a codeword by a turbo code decoder. The disadvantage of the resulting combined code is its extremely low correcting ability in the presence of errors in the check bits of the codeword. The article shows that the correcting ability of the presented code can be significantly increased by multiplying the decoded values of the check bits by reduction factors.
On reducing the rate of deposit formation on the AISI 316L steel surface
Authors: Dasaev M R , Kalakutskaya O V , Ryzhenkov O V
Published: February 2024

The article is devoted to the investigation of the rate of deposit formation on the hydrophobic modified surface of experimental samples made of AISI 316L sheet steel and samples of AISI 316L steel powder printed using selective laser melting technology. A saturated solution of CaCO3 was used as a model medium during the research. The research established that hydrophobization of the surface of AISI 316L steel based on laser texturing with the subsequent formation of molecular layers of surfactants can significantly reduce the rate of deposit formation.
Experimental studies of the deformation characteristics of mudstones under high temperature exposure
Authors: Blokhin D I , Zakorshmennyi I M , Minaev V I , Nesterova V G , Shilin N A
Published: February 2024

The article presents the results of laboratory thermomechanical tests of argillite samples. It has been confirmed that the deformation-strength properties of the studied type of geomaterials undergo significant changes under high-temperature influences. Features of changes in the values of deformations of argillite samples at various stages of heating were revealed. It is shown that the research results can be used in modeling thermomechanical processes occurring during underground gasification of coal in a reaction channel, to predict the development of deformation of the host rocks of an underground gas generator.
Investigation of the effect of ultrasound during explosion welding on the formation of the structure and properties of the aluminum-steel composite
Authors: Kuz’min E V , Korolev M P , Kuz’min S V , Lysak V I
Published: February 2024

The paper presents the results of experimental studies of the effect of ultrasonic vibrations during explosion welding on the formation of the structure and properties of the connection of steel with aluminum. It is shown that the introduction of ultrasound during explosive loading has a significant effect on the structure and properties of the aluminum-steel compound. The chemical composition of the areas of the melted metal is considered. The results of the tensile strength of aluminum+steel composite layers are presented. It has been experimentally established that the introduction of additional ultrasound energy in the process of explosive loading of an aluminum-steel compound contributes to a significant reduction in the amount of molten metal at the junction boundary throughout the studied range.
Research of the application of nickel-chrome-silicon bronze BrNHK for the manufacture of helical compression springs
Authors: Silaev Mikhail , Lenina Victoria , Mirzaev Osman , Timokhov Roman , Sokolova Viktoriia , Akhmetshin Stanislav , Yakushev Adel
Published: February 2024

The results of a study of the mechanical characteristics of the BrNHK bronze alloy using the acoustic emission method are presented. The mechanical characteristics of BrNHK-2.5-0.6-0.7 wire were studied after various heat treatment modes. The widespread use of bronze alloy BrKMts3-1 is due to its low price, while the mechanical and operational properties satisfy both consumers and spring manufacturers, since the technology for manufacturing springs from this alloy is not fundamentally different from the technology for manufacturing springs from cold-worked wire. In turn, the BrB2 alloy is considered a scarce alloy and is used only for springs intended for special equipment, since the properties of this alloy after hardening heat treatment are not inferior to cold-worked carbon steels. Given the increased cost of beryllium, work is underway both to reduce the beryllium content and to switch to beryllium-free alloys.
Features of deformation resistance of polypropylene polymer films
Authors: Eshbaeva Ulbosin , Zufarova Dilobar , Baltabaeva Barno
Published: February 2024

The article studies the physical and mechanical properties of experimental polymer materials, which are determined by parameters such as Tensile strength s, tensile model E, relative elongation at break ε, which affect the quality of printing under other equal conditions. Experimental studies on the elongation of biaxially oriented polypropylene and polyethylene polymer films were carried out in accordance with the requirements of GOST 14236-81. The tensile modulus E was determined according to Hooke’s law when observing a rectilinear area in the limit of small deformations on the stretching diagram of polymer films.
Dynamics of heat release in a dual-fuel engine
Authors: Lopatin O P
Published: February 2024

The increasing attention to the use of dual-fuel engines with compression ignition leads to the need to study the thermal engineering processes occurring in them. A model for calculating the thermal engineering stages in a cylinder of a dual-fuel engine with a refined composition of the working fluid is presented, including the determination of fuel supply characteristics, fuel injection and evaporation functions and allowing theoretically to determine with high accuracy the pressure function, cycle operation, power, efficient and thermal criteria for the operation of a dual-fuel engine. The paper attempts to show the mutual relationship between the individual processes of heat generation, their influence on the design parameters under the operating conditions characteristic of a dual-fuel engine, as well as on the operating conditions of components and parts.
Flux-pinning mediated superconducting diode effect in NbSe2/CrGeTe3 heterostructure
Authors: Mehrnejat A , Hatnean M Ciomaga , Rosamond M C , Banerjee N , Balakrishnan G , Savel’ev S E , Dejene F K
Published: February 2024

In ferromagnet/superconductor bilayer systems, dipolar fields from the ferromagnet can create asymmetric energy barriers for the formation and dynamics of vortices through flux pinning. Conversely, the flux emanating from vortices can pin the domain walls of the ferromagnet, thereby creating asymmetric critical currents. Here, we report the observation of a superconducting diode effect (SDE) in a NbSe2/CrGeTe3 van der Waals heterostructure in which the magnetic domains of CrGeTe3 control the Abrikosov vortex dynamics in NbSe2. In addition to extrinsic vortex pinning mechanisms at the edges of NbSe2, flux-pinning-induced bulk pinning of vortices can alter the critical current. This asymmetry can thus be explained by considering the combined effect of this bulk pinning mechanism along with the vortex tilting induced by the Lorentz force from the transport current in the NbSe2/CrGeTe3 heterostructure. We also provide evidence of critical current modulation by flux pinning depending on the history of the field setting procedure. Our results suggest a method of controlling the efficiency of the SDE in magnetically coupled van der Waals superconductors, where dipolar fields generated by the magnetic layer can be used to modulate the dynamics of the superconducting vortices in the superconductors.
Klein tunneling degradation and enhanced Fabry-Pérot interference in graphene/h-BN moiré-superlattice devices
Authors: Tran Viet-Anh , Nguyen Viet-Hung , Charlier Jean-Christophe
Published: February 2024

Hexagonal boron-nitride (h-BN) provides an ideal substrate for supporting graphene devices to achieve fascinating transport properties, such as Klein tunneling, electron optics and other novel quantum transport phenomena. However, depositing graphene on h-BN creates moiré superlattices, whose electronic properties can be significantly manipulated by controlling the lattice alignment between layers. In this work, the effects of these moiré structures on the transport properties of graphene are investigated using atomistic simulations. At large misalignment angles (leading to small moiré cells), the transport properties (most remarkably, Klein tunneling) of pristine graphene devices are conserved. On the other hand, in the nearly aligned cases, the moiré interaction induces stronger effects, significantly affecting electron transport in graphene. In particular, Klein tunneling is significantly degraded. In contrast, strong Fabry-Pérot interference (accordingly, strong quantum confinement) effects and non-linear I-V characteristics are observed. P-N interface smoothness engineering is also considered, suggesting as a potential way to improve these transport features in graphene/h-BN devices.
Effect of heat treatment on microstructural characteristics and mechanical properties of hypereutectic B390 aluminium alloys modified by phosphorus and bismuth
Authors: Jiandon Porawit , Talangkun Sukangkana , Ponhan Kowit
Published: February 2024

This study investigated the effects of solution treatment and aging processes on microstructural characteristics and mechanical properties of hypereutectic B390 Al-Si Alloy modified by phosphorus (P) and bismuth (Bi). The morphology evolution of primary Si, eutectic Si, intermetallic compounds, and secondary dendrite arm spacing (SDAS) of both initial and modified alloys were investigated in as-cast and heat-treated conditions. It was found that the combination of 0.1 wt%P and 0.5 wt%Bi in B390 alloy resulted in a remarkable modification and refinement of primary Si, eutectic Si, and SDAS compared to initial specimens in the as-cast condition. After heat treating, the fine lamellar eutectic Si and intermetallic compounds underwent a higher degree of fragmentation and coarsening, appearing as small round particles, leading to a more pronounced formation of a supersaturated solid solution. Additionally, the peak aging time of the B390-P-Bi alloy was only 7 h, 2 h less than the initial specimen. After T6 treatment and addition of both 0.1 wt%P and 0.5 wt%Bi, the B390-P-Bi alloy exhibited a smaller rounded Mg3Bi2 phase at peak aging with a 62.07% size reduction compared to the B390-Bi alloy. The results show that adding P with Bi enhanced hardness, ultimate tensile strength (UTS) and elongation because of refinement of the SDAS, primary Si and eutectic Si. These refinements played a crucial role in increasing tensile strength by more effective strengthening through precipitation and grain size reduction. The B390-P-Bi alloy is a promising choice for applications requiring a balance between strength and ductility.
The investigation on properties of Ti- 5Si and Ti- 5Nb implant alloys coated by bioactive based composite coating
Authors: Jabbar Shahad Abduladheem , Jamal Abdulkader Niveen , Ahmed Payman Sahbah
Published: February 2024

Titanium (Ti) alloys are widely utilized in orthopedics owing to their excellent mechanical properties and biocompatibility. To improve their resistance to corrosion and ion release properties, substrates of Ti alloy have been produced employing powder metallurgy by adding alloying elements (Si and Nb) at 5 wt% along with CP-Ti. Two torch flame sprays have been utilized for coating the Ti-5Nb and Ti-5Si alloys with two kinds of nanocoating: HAp+25%SiC (type-A) and ZSM5 + 25%ZrO2 (type-B). These nanocoating combinations represented bioactive and bioinert to combine the biological and mechanical properties of the implant surface. Different tests and characterization techniques have been carried out, including SEM, XRD, AFM, AAS, hardness, adhesion strength, and corrosion resistance. The results manifested that the coatings (types A and B) improved the properties of Ti alloys; however, ZSM5 + 25%ZrO2 has better properties than type-A in terms of less porosity, higher crystallinity%, higher hardness, higher adhesion strength, lower corrosion rate, and less Ti ions release. Comparing the results of the two Ti alloys, Ti-5Si has higher hardness, corrosion resistance, and less ionic release than the Ti-5Nb alloy. Hence, the Ti-5Si coated by ZSM5 + 25%ZrO2 (B coated Ti-5Si) is the best sample in this study.
Experimental implementation of quantum-walk-based portfolio optimization
Authors: Qu Dengke , Matwiejew Edric , Wang Kunkun , Wang Jingbo , Xue Peng
Published: February 2024

The application of quantum algorithms has attracted much attention as it holds the promise of solving practical problems that are intractable to classical algorithms. One such application is the recent development of a quantum-walk-based optimization algorithm approach to portfolio optimization under the modern portfolio theory framework. In this paper, we demonstrate an experimental realization of the alternating phase-shift and continuous-time quantum walk unitaries that underpin this quantum algorithm using optical networks and single photons. The experimental analysis confirms that the probability of states corresponding to high-quality solutions is efficiently amplified by increasing the number of phase-shift and quantum walk iterations. This work provides strong evidence for practical applications of quantum-walk-based algorithms such as financial portfolio optimization.
Nanocomposite materials as observed by mass-selective neutron spectroscopy
Authors: Krzystyniak Matthew , Romanelli Giovanni , Grabowska Beata , Fernandez-Alonso Felix
Published: February 2024

This work provides a current, critical view of the application of MAss-selective Neutron SpEctroscopy (MANSE) to nanocomposite materials. MANSE is a unique technique made possible owing to the existence of the pulsed neutron sources. At present, the only operating MANSE spectrometer in the world, VESUVIO, is located at the ISIS Neutron and Muon Source in the UK. We start by providing a brief description of the neutron Compton scattering, the anatomy of a mass-selective neutron spectrometer, and the experimental data treatment. We continue by briefly outlining the main quantum mechanical concepts, models and approximations relevant both to the ab initio prediction and experimental measurement of main MANSE observables. Next, we present several recent exemplars chosen to highlight the use of MANSE in the field of nanocomposites. Our examples include, in chronological order, encapsulated nanoparticles in amorphous silica gel, bioactive glass-ionomer cement, Cu-Ti-C composites, and sodium carboxymethyl starch-based binders in the presence of a mineral matrix. We close by providing our view of the ongoing and future challenges and opportunities in the mass-selective neutron investigation of NQEs in nanocomposite materials.
Bridging the gap between high-level quantum chemical methods and deep learning models
Authors: Prasad Viki Kumar , Otero-de-la-Roza Alberto , DiLabio Gino A
Published: February 2024

Supervised deep learning (DL) models are becoming ubiquitous in computational chemistry because they can efficiently learn complex input-output relationships and predict chemical properties at a cost significantly lower than methods based on quantum mechanics. The central challenge in many DL applications is the need to invest considerable computational resources in generating large (

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) training sets such that the resulting DL model can be generalized reliably to unseen systems. The lack of better alternatives has encouraged the use of low-cost and relatively inaccurate density-functional theory (DFT) methods to generate training data, leading to DL models that lack accuracy and reliability. In this article, we describe a robust and easily implemented approach based on property-specific atom-centered potentials (ACPs) that resolves this central challenge in DL model development. ACPs are one-electron potentials that are applied in combination with a computationally inexpensive but inaccurate quantum mechanical method (e.g. double-ζ DFT) and fitted against relatively few high-level data (

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), possibly obtained from the literature. The resulting ACP-corrected methods retain the low cost of the double-ζ DFT approach, while generating high-level-quality data in unseen systems for the specific property for which they were designed. With this approach, we demonstrate that ACPs can be used as an intermediate method between high-level approaches and DL model development, enabling the calculation of large and accurate DL training sets for the chemical property of interest. We demonstrate the effectiveness of the proposed approach by predicting bond dissociation enthalpies, reaction barrier heights, and reaction energies with chemical accuracy at a computational cost lower than the DFT methods routinely used for DL training data set generation.
ExpoSeq: simplified analysis of high-throughput sequencing data from antibody discovery campaigns
Authors: Sørensen Christoffer V , Hofmann Nils , Rawat Puneet , Sørensen Frederik V , Ljungars Anne , Greiff Victor , Laustsen Andreas H , Jenkins Timothy P
Published: February 2024

High-throughput sequencing (HTS) offers a modern, fast, and explorative solution to unveil the full potential of display techniques, like antibody phage display, in molecular biology. However, a significant challenge lies in the processing and analysis of such data. Furthermore, there is a notable absence of open-access user-friendly software tools that can be utilized by scientists lacking programming expertise. Here, we present ExpoSeq as an easy-to-use tool to explore, process, and visualize HTS data from antibody discovery campaigns like an expert while only requiring a beginner’s knowledge.

Availability and implementation

The pipeline is distributed via GitHub and PyPI, and it can either be installed as a package with pip or the user can choose to clone the repository.
pycofitness—Evaluating the fitness landscape of RNA and protein sequences
Authors: Pucci Fabrizio , Zerihun Mehari B , Rooman Marianne , Schug Alexander
Published: February 2024

Motivation

The accurate prediction of how mutations change biophysical properties of proteins or RNA is a major goal in computational biology with tremendous impacts on protein design and genetic variant interpretation. Evolutionary approaches such as coevolution can help solving this issue.

Results

We present pycofitness, a standalone Python-based software package for the in silico mutagenesis of protein and RNA sequences. It is based on coevolution and, more specifically, on a popular inverse statistical approach, namely direct coupling analysis by pseudo-likelihood maximization. Its efficient implementation and user-friendly command line interface make it an easy-to-use tool even for researchers with no bioinformatics background. To illustrate its strengths, we present three applications in which pycofitness efficiently predicts the deleteriousness of genetic variants and the effect of mutations on protein fitness and thermodynamic stability.

Availability and implementation

https://github.com/KIT-MBS/pycofitness.