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Characterizing the number of sheets in a stack of paper typically involves mechanical separation of the individual sheets. Here, we explore an nondestructive method that can be applied to the intact paper stack. Namely, terahertz time-of-flight tomography, together with post signal-processing technique sparse deconvolution based on a two-step iterative shrinkage-thresholding algorithm (SD/TWIST), is employed to reconstruct the stratigraphy of stacks of sheets of paper with multilayered structure in a nondestructive and noncontact manner. The double-Gaussian mixture model (DGMM) is also incorporated to suppress dispersion in the reflected THz echoes. The effectiveness and accuracy of the proposed adaptive sparse-deconvolution method are verified experimentally and numerically. Compared with the commonly used frequency wavelet-domain deconvolution (FWDD) method and previous implementations of sparse deconvolution based on an iterative-shrinkage and thresholding algorithm (SD/IST), the proposed sparse-deconvolution approach can provide a clearer and rapid stratigraphic reconstruction of the paper stacks studied, while ensuring accurate thickness information for each paper sheet in the presence of noise, revealing the potential usage of real-time THz tomographic-image processing. [ABSTRACT FROM AUTHOR]

The paper proposed a new type of electromagnetic control support roll to obtain a better ability of controlling the plate shape. According to the principle of induction heating, the bulge shape of the support roll and the contact pressure between the rolls are changed to control the crown of the work roll. To analyze the shape control characteristics of the electromagnetic control sleeve support roll, the roll system model of the four-high mill was established and the no-load bulging experiment was carried out. The simulation results show that under different roll sleeve thickness, current frequency and current intensity, the bulge amount of support roll, contact pressure between rolls and work roll crown increase with heating time, but the growth rate gradually decreases to zero. The bulge of the support roll, the contact pressure between the rolls, the crown of the work roll change quasi-linearly with the current frequency and parabolically with the current intensity. The bulging amount of the support roll and contact pressure decrease with the increase of the thickness of the roll sleeve, and the crown of the work roll increases first and then decreases. This paper verifies the feasibility of adjusting the shape of roll gap by electromagnetic control sleeve support roll, which provides a basis for multi-zone joint control. [ABSTRACT FROM AUTHOR]

The dephosphorization behavior of multiphase steel slag in converter steelmaking process is very important for higher steel quality with ultra-low phosphorus content. In this paper, the multiphase steel slag with different BaO content reacted with hot metal at 1873 K temperature. The influence of the reaction on dephosphorization was investigated. The mineralogical phase was observed. The phosphorus partition between phosphorus enriched phase and liquid phase was discussed. The phosphorus partition ratio between steel slag and hot metal was obtained. The main mineralogical phases of steel slag were phosphorus enriched phase mCa2SiO4-Ba1-xCax(PO4)2 and RO (FeO/MgO) phase. The barium existed in phosphorus enriched phase and liquid phase, not in RO phase. The phosphorus content in phosphorus enriched phase increased from 1.12% to 1.36% with the addition of BaO. The phosphorus partition ratio between phosphorus enriched phase and liquid phase increased from 2.60 to 3.77, increased 45.00% by the addition of BaO. The phosphorus partition ratio between steel slag and hot metal increased from 55.35 to 97.50, increased 76.15% by the addition of BaO in steel slag. [ABSTRACT FROM AUTHOR]

Context. The mean motion resonance is the most important mechanism that may dominate the dynamics of a planetary system. In a multi-planetary system consisting of N ≥ 3 planets, the planets may form a resonant chain when the ratios of orbital periods of planets can be expressed as the ratios of small integers T1: T2: ⋯ : TN = k1: k2: ⋯ : kN. Due to the high degree of freedom, the motion in such systems could be complex and difficult to depict. Aims. In this paper, we investigate the dynamics and possible formation of the resonant chain in a triple-planet system. Methods. We defined the appropriate Hamiltonian for a three-planet resonant chain and numerically averaged it over the synodic period. The stable stationary solutions – apsidal corotational resonances (ACRs) – of this averaged system, corresponding to the local extrema of the Hamiltonian function, can be searched out numerically. The topology of the Hamiltonian around these ACRs reveals their stabilities. We further constructed the dynamical maps on different representative planes to study the dynamics around the stable ACRs, and we calculated the deviation (χ2) of the resonant angle in the evolution from the uniformly distributed values, by which we distinguished the behaviour of critical angles. Finally, the formation of the resonant chain via convergent planetary migration was simulated and the stable configurations associated with ACRs were verified. Results. We find that the stable ACR families arising from circular orbits always exist for any resonant chain, and they may extend to a high eccentricity region. Around these ACR solutions, regular motion can be found, typically in two types of resonant configurations. One is characterised by libration of both the two-body resonant angles and the three-body Laplace resonant angle, and the other by libration of only two-body resonant angles. The three-body Laplace resonance does not seem to contribute to the stability of the resonant chain much. The resonant chain can be formed via convergent migration, and the resonant configuration evolves along the ACR families to eccentric orbits once the planets are captured into the chain. Ideally, our methods introduced in this paper can be applied to any resonant chain of any number of planets at any eccentricity. [ABSTRACT FROM AUTHOR]

Aims. The most reliable sources for determining absolute stellar parameters are the double-lined eclipsing binary systems. Some of these systems also show apsidal motion, characterized by the variable log k2. This point grants us the possibility of investigating the stellar interior, specifically the degree of stellar mass concentration. The first studies carried out about four decades ago on this topic showed appreciable discrepancies not only with respect to the comparison between the observed absolute dimensions and their theoretical counterparts, but mainly concerning the degree of mass concentration through the analysis of their apsidal motions. Fortunately, this scenario has been gradually improving with the advances in the quality of observational techniques and advances in the input physics of the evolutionary stellar models (e.g. opacities, thermonuclear reactions, equations of state, numerical techniques). These new developments in the input physics has improved the comparison between observations and the values predicted by theory, including the apsidal motion rates. This progress has lead us to investigate second-order effects such as rotation and dynamic tides. In this paper we deal with the effects of rotation on the degree of mass concentration. Methods. The stellar models were calculated using the MESA package. The mass range studied here was 0.40–25.0 M⊙ for a generic chemical composition characterized by X = 0.70 and Z = 0.02. The present models were computed without taking into account core overshooting in order to highlight the effects of rotation. Each model was followed from the pre-main sequence until the central hydrogen content is of the order of or less than 0.03, covering the range of masses and evolutionary status of the double-lined eclipsing binaries showing apsidal motion. Regarding the calculation of the internal structure coefficients, we integrated the Radau equation using the fifth-order Runge-Kutta method and a tolerance level of 10−7. As an auxiliary tool, homology transformations have been used to explain, qualitatively, how the equation of state, thermonuclear reactions, and convection impact the degree of mass concentration of the models. Results. In our past studies on the effects of rotation on log k2 an average correction was used for all models together. For this a small range of masses (2.0, 7.0, 15.0 M⊙) has been used. In the present paper the corrections due to the effects of rotation in log k2 are presented for each mass individually and for three evolutionary phases. This point is particularly important, given that these corrections show a clear dependence on the mass and on the evolutionary status. Such corrections can be easily introduced into the theoretical calculation of apsidal motion rates through a linear equation. A typical correction due to the rotation effects is of the order of −0.03 in log k2. [ABSTRACT FROM AUTHOR]

The 1:N mean motion resonances (MMRs) with Neptune are of particular interest in astronomy research because they have two asymmetric resonance islands, where the distribution of trapped objects may bear important clues to resolving the history of the Solar System. To explore the dynamics of these resonances and to investigate whether the imprints left by the early stage evolution can be preserved in the resonances, we conducted a comprehensive analysis of the 1:2 and 1:3 resonances. By mainly adopting the frequency analysis method, we calculated the proper frequencies of the motion of objects in the resonances and determined the secular mechanisms that influence the dynamics. Using the spectral number (SN) as an indicator of orbital regularity, we constructed dynamical maps on representative planes. After comparing the structures in the maps with the locations of the secular mechanisms, we find that the von-Zeipel-Lidov-Kozai mechanism and the 푔 = 2s mechanism destabilize the influenced orbits and thus sculpt the overall structure of the 1:2 and 1:3 resonances. The secular resonance of 2푔 − s = s8 opens a channel for objects to switch between the leading and trailing resonance islands, which can alter the population ratio between these two islands. The secondary resonances associated with the quasi 2:1 resonance between Uranus and Neptune were also detected, likely introducing more chaos to the motion. The fine dynamical structures of the 1:2 and 1:3 resonances revealed in this paper, combined with knowledge of resonant capture, provide a compelling explanation for the eccentricity distribution of observed Twotinos. Furthermore, we anticipate a more complete understanding of the history of planetary migration in the Solar System can be achieved by comparing the results in this paper with the populations in the 1:N resonances, with forthcoming observations offering more objects for study in the future. [ABSTRACT FROM AUTHOR]

Context. Quantifying the number density and physical characteristics of extragalactic polarized sources is important for the successful planning of future studies based on Faraday rotation measure (RM) grids of polarized sources to probe foreground Galactic and intergalactic magnetic fields. However, it is proving very hard to detect polarized signal from the population of very faint (sub-mJy) polarized sources at low radio frequencies, and their properties are mostly unknown. LOFAR can play an important role in such studies thanks to its sensitivity and angular resolution, combined with the precision on the inferred RM values that can be achieved through low-frequency broad-band polarimetry. Aims. The aim of this study is to probe the sub-mJy polarized source population with LOFAR. In this first paper, we present the method used to stack LOFAR polarization datasets, the resulting catalog of polarized sources, and the derived polarized source counts. Methods. The European Large Area ISO Survey-North 1 (ELAIS-N1) field, one of the deepest of the LOFAR Two-Metre Sky Survey (LoTSS) Deep Fields so far, was selected for a polarimetric study at 114.9–177.4 MHz. A total area of 25 deg2 was imaged at 6″-resolution in the Stokes Q and U parameters. Alignment of polarization angles was done both in frequency and in Faraday space before stacking datasets from 19 eight-hour-long epochs taken in two different LOFAR observing cycles. A search for polarized sources was carried out in the final, stacked dataset, and the properties of the detected sources were examined. The depolarization level of sources known to be polarized at 1.4 GHz was quantified. Results. A one-sigma noise level, σQU, of 19 µJy beam−1 was reached in the central part of the field after stacking. Twenty-five polarized sources were detected above 8σQU, five of which had not been detected in polarization at any other radio frequencies before. Seven additional polarized components were found by lowering the threshold to 6σQU at positions corresponding to sources known to be polarized at 1.4 GHz. In two radio galaxies, polarization was detected from both radio lobes, so the final number of associated radio continuum sources is 31. The detected sources are weakly polarized, with a median degree of polarization of 1.75% for the sample of sources detected in polarized emission. For the 10 polarized sources previously identified in a pilot LOFAR study of the ELAIS-N1 field at 20″-resolution, the RM values are consistent but the degrees of polarization are higher in the 6″-resolution data. The sources previously detected in polarization at 1.4 GHz are significantly depolarized at 150 MHz. The catalog is used to derive the polarized source counts at 150 MHz. Conclusions. This is the deepest and highest-resolution polarization study at 150 MHz to date. A full characterization of the sources and an analysis of the catalog will be presented in Paper II. [ABSTRACT FROM AUTHOR]

Context. Recent molecular surveys have revealed the rich gas organization of sonic-like filaments at small scales (so-called fibers) in all types of environments prior to the formation of low- and high-mass stars. These fibers form at the end of the turbulent cascade and are identified as the fine substructure within the hierarchical nature of the gas in the interstellar medium (ISM). Aims. Isolated fibers provide the subsonic conditions for the formation of low-mass stars. This paper introduces the Emergence of high-mass stars in complex fiber networks (EMERGE) project, which investigates whether complex fiber arrangements (networks) can also explain the origin of high-mass stars and clusters. Methods. We analyzed the EMERGE Early ALMA Survey including seven star-forming regions in Orion (OMC-1,2,3, and 4 South, LDN 1641N, NGC 2023, and the Flame Nebula) that were homogeneously surveyed in three molecular lines (N2H+J = 1–0, HNC J = 1–0, and HC3N J = 10–9) and in the 3 mm continuum using a combination of interferometric ALMA mosaics and IRAM-30 m single-dish (SD) maps, together with a series of Herschel, Spitzer, and WISE archival data. We also developed a systematic data reduction framework allowing the massive data processing of ALMA observations. Results. We obtained independent continuum maps and spectral cubes for all our targets and molecular lines at different (SD and interferometric) resolutions, and we explored multiple data combination techniques. Based on our low-resolution (SD) observations (30″ or ~12 000 au), we describe the global properties of our sample, which covers a wide range of physical conditions, including low-(OMC-4 South and NGC 2023), intermediate (OMC-2, OMC-3, and LDN 1641N), and high-mass (OMC-1 and Flame Nebula) star-forming regions in different evolutionary stages. The comparison between our single-dish maps and ancillary YSO catalogs denotes N2H+ (1–0) as the best proxy for the dense, star-forming gas in our targets, which show a constant star formation efficiency and a fast time evolution of ≲1 Myr. While apparently clumpy and filamentary in our SD data, all targets show a much more complex fibrous substructure at the enhanced resolution of our combined ALMA+IRAM-30 m maps (4″.5 or ~2000 au). A large number of filamentary features at subparsec scales are clearly recognized in the high-density gas (≳ 105 cm−3) that is traced by N2H+ (1–0) directly connected to the formation of individual protostars. Surprisingly, this complex gas organization appears to extend farther into the more diffuse gas (~103−104 cm−3) traced by HNC (1–0). Conclusions. This paper presents the EMERGE Early ALMA Survey, which includes a first data release of continuum maps and spectral products for this project that are to be analysed in future papers of this series. A first look at these results illustrates the need of advanced data combination techniques between high-resolution interferometric (ALMA) and high-sensitivity, low-resolution single-dish (IRAM-30 m) datasets to investigate the intrinsic multiscale, gas structure of the ISM. [ABSTRACT FROM AUTHOR]

This paper is devoted to the finite element analysis for the Bean–Kim model governed by the full 3D Maxwell equations. Describing type-II superconductivity at the macroscopic level, this model leads to a challenging coupled system consisting of the Faraday equation and a hyperbolic quasi-variational inequality (QVI) of the second kind with L1-type nonlinearity, that arises explicitly from the magnetic field dependency in the critical current. With the involved Maxwell coupling in the 3D H(curl)-setting, the hyperbolic QVI character poses the primary challenge in the numerical investigation. Two mixed finite element methods based on implicit Euler and leapfrog time-stepping are proposed. On the one hand, the implicit Euler method results in a nonstandard system of curl-curl elliptic QVI with a first-order curl-type nonlinearity. Though the well-posedness of this system is guaranteed, its numerical realization is not straightforward and requires the use of a two-stage iteration process of high computational complexity. On the other hand, by approximating the electric and magnetic fields at two different time step levels, the leapfrog method turns out to be more suitable as it naturally eliminates the notorious QVI structure. More importantly, utilizing suited subdifferential and optimization techniques, we are able to prove an efficiently computable explicit formula for its exact solution in terms of the electric field, which makes its numerical computation substantially more favorable than the Euler method. As further advantages, the leapfrog method applies to broad scenarios involving low regular data of bounded variation (BV) in time for both the applied current source and the temperature distribution. Through nonstandard technical arguments tailored to the BV data, our analysis proves the conditional stability and, eventually, the uniform convergence of the proposed leapfrog method. This paper is closed by 3D numerical tests showcasing the reasonable and efficient performance of the proposed numerical solution. [ABSTRACT FROM AUTHOR]

Bike-sharing system has become an indispensable element of sustainable urban transportation, effectively resolving the "last mile" transportation challenge for city dwellers. A major daily operational task in these systems is planning a fleet to rebalance the bikes over time, ensuring the optimal availability of bikes and docks to users. Recycling is also a daily work with the an increase in the number of broken bikes. However, rebalancing or recycling operation is always regarded as an independent tasks. They are separately studied in existing papers. Thus, this paper develops an operational strategy for recycling broken bikes during the rebalancing process, and studies the combination of the station inventory and vehicle routing problems. First, an inventory routing model is constructed with the aim of minimizing the total costs including procurement, expected user loss, inventory and transportation costs. Then, a two-stage iterative algorithm is developed with both exact and heuristic algorithms. We use real-world data from Capital Bikeshare to test our proposed model and approach, which shows the two-stage iterative algorithm is efficient and outperforms existing solutions in reducing total costs. Finally, the sensitivity analysis is performed on key parameters such as the vehicle's capacity, unit penalty costs for customer dissatisfaction events, unit inventory holding costs and the observation period of rebalancing. It shows that enterprises can reduce the total cost by altering vehicle's capacity, reducing the unit inventory holding costs or changing the observation period of rebalancing. [ABSTRACT FROM AUTHOR]

With the increasing public awareness of environmental protection, corporate social responsibility has become an important component of sustainable development and competitive advantage for many enterprises. Although there are many studies on corporate social responsibility in the supply chain, there is still a lack of research on the impact of corporate social responsibility on various decision-makers in the competitive green supply chain dominated by upstream enterprises. Therefore, taking into account the greenness and corporate social responsibility, the paper proposes three Stackelberg game models with the two-echelon supply chain consisting of two competing manufacturers and one socially responsible retailer. We develop a series of propositions and corollaries to determine the optimal solutions and offer some managerial insights. The main novelties and contributions of the paper can be demonstrated in two aspects. First, the paper simultaneously considers the impact of competition intensity and CSR level on wholesale prices, retail prices and greenness level. Second, the paper discusses the impact of two manufacturers with different market positions investing in green products on the profits and utility of supply chain members. Numerical illustrations prove that the level of corporate social responsibility is negatively correlated with retailer profitability and the retailer achieve the highest profits when sub-dominant manufacturer produces green products. [ABSTRACT FROM AUTHOR]

In this paper, we establish optimality conditions and sensitivity analysis of set-valued optimization problems in terms of higher-order radial derivatives. First, we obtain the optimality conditions with separated derivatives for a set-valued optimization problem, here separated derivatives means the derivatives of objective and constraint functions are different. Then, some duality theorems for a mixed type of primal-dual set-valued optimization problem are gained. Finally, several results concerning higher-order sensitivity analysis are presented. The main results of this paper are illustrated by some concrete examples. [ABSTRACT FROM AUTHOR]

This paper discusses a two-stage capacitated time minimization transportation problem with the restricted flow (TSCTMTP-F) in which the transportation takes place in two stages and only a specified amount of commodity is transported in both stages. The total amount F1 is transported during Stage-I and F2 during Stage-II, and the objective is to minimize the sum of the transportation times for Stage-I and Stage-II. In 2017, Kaur et al. [RAIRO-Oper. Res. 51 (2017) 1169–1184] studied this problem and developed a polynomially bounded iterative algorithm (Algorithm-A) to solve TSCTMTP-F. However, their proposed algorithm has some flaws and may not always yield an optimal solution to the problem TSCTMTP-F. An improved iterative algorithm (Algorithm-C) is proposed in this paper that guarantees an optimal solution to the problem. Various theoretical results prove the convergence and efficiency of Algorithm-C to obtain an optimal solution to the problem TSCTMTP-F. Numerical problems are included in the support of theory along with a counter-example for which Algorithm-A fails to obtain its optimal solution. Computational experiments on a variety of test problems have been carried out to validate the convergence and efficiency of Algorithm-C. [ABSTRACT FROM AUTHOR]

In modern times, customers are increasingly aware of the environmental risks posed by the premature expiration of smart products. To safeguard the environment, companies have embraced green technology when procuring products. As a result, it is challenging for business managers to capture the market by offering the best quality products at a reasonable price, regardless of the economic situation. This paper presents a production model incorporating reverse logistics to identify defective products. The model involves learning through production and utilizes green technologies. Additionally, a portion of the assembled products is remanufactured after being received from consumers. The remanufactured items are screened and distributed to markets. Both new and remanufactured products are sold to the market based on their quality in the first and second markets, respectively. To reduce product spoilage, manufacturers employ green technology like liquid cooling technology. The numerical results demonstrate that by investing in liquid cooling technology, the production store can reduce spoilage items by 8.50%, a positive environmental outcome regarding waste reduction, and due to the learning effect, the total cost can decrease by 1.44%. The paper includes numerical and sensitivity analyses accompanied by graphs. [ABSTRACT FROM AUTHOR]

With the rapid development of retail platforms, many manufacturers use retail platforms to encroach into the retail market (i.e., a type manufacturer encroachment) and gray market is increasingly prevalent in various industries. This paper considers a manufacturer who directly sells product 1 in the domestic market and sells product 2 through an incumbent retailer in the overseas market and a gray marketer can divert product 1 across markets without authorized (we call it gray market). In this paper, we examine the interaction between manufacturer encroachment and gray market. We find that when the domestic price of product 1 is sufficiently low, the gray marketer can successfully enter the overseas market without and with encroachment. Second, regardless of whether there is a gray market threat, the manufacturer has an incentive to encroach through retail platform when the commission rate is low. Moreover, the manufacturer's incentive to encroach varies with the domestic price of product 1 and gray market threat. Finally, manufacturer encroachment can reduce the scale of the gray market and even eliminate the gray market under certain conditions. The gray marketer always suffers from manufacturer encroachment while the retailer can benefit from manufacturer encroachment. [ABSTRACT FROM AUTHOR]

Laser cladding uses a high-energy laser beam as a heat source to rapidly melt and solidify the cladding material onto the substrate to form a high-performance coating. This technology provides an efficient and economical method to repair and remanufacture precision equipment such as engines and spacecraft. However, the inherent non-equilibrium solidification properties of laser cladding often lead to problems such as coating anisotropy, high porosity, and elemental segregation. Optimizing process parameters and heat treatment do not always eliminate these defects. Therefore, it is necessary to seek a more appropriate solution. Introducing laser remelting on the surface or between the layers of the coating to cause it to remelt and redistribute can refine the grain size, reduce defects, and improve the uniformity of the composition, thus enhancing the performance of the coating. This paper reviews and summarizes the application and development status of laser remelting technology in laser cladding and discusses it in terms of surface quality, hardness, wear resistance, and corrosion resistance of the coating. It also identifies the potential of external field-assisted laser remelting technology in further optimizing coating performance. Finally, based on the review, suggestions are provided for selecting remelting parameters. [ABSTRACT FROM AUTHOR]

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The iron ore screening process plays a pivotal role in determining the dimensions of pellets that enter the firing process of a pelletizing plant. The particle size distribution resulting from this process significantly influences the gas flow permeability within the induration furnace. This paper investigates the latest developments in screening technology, highlighting advancements that contribute to elevated levels of screening efficiency and enhanced plant productivity. The discussion turns around how these technological innovations pave the way for achieving the objective of producing high-quality iron ore pellets with minimal energy consumption, thereby improving the overall performance of the plant. The paper offers a comprehensive overview of the screening process flowsheet, encompassing these cutting-edge technologies, associated process parameters, and benefits quantified through DEM simulations. Moreover, it examines the consequential impact on greenhouse gas (GHG) emissions, providing a holistic perspective on the environmental implications of these advancements. [ABSTRACT FROM AUTHOR]

An improved algorithm for diffractive optical element (DOE) with high imaging quality is proposed in this paper. The algorithm is designed based on amplitude division between signal and noise regions, further subdivides the noise region into two distinct parts. The image quality in the signal region will be effectively improved by employing a partition-constraint strategy, which imposes amplitude freedom on the first noise region while enforcing strict amplitude constraints on the second noise region. The principle of the algorithm, simulation analysis, and experimental results are presented. The simulation and experimental results demonstrate that the algorithm is feasible. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) reconstruction technology is the key technology to establish and express the objective world by using computer, and it is widely used in real 3D, automatic driving, aerospace, navigation and industrial robot applications. According to different principles, it is mainly divided into methods based on traditional multi-view geometry and methods based on deep learning. This paper introduces the above methods from the perspective of three-dimensional space representation. The feature extraction and stereo matching theory of traditional 3D reconstruction methods are the theoretical basis of 3D reconstruction methods based on deep learning, so the paper focuses on them. With the development of traditional 3D reconstruction methods and the development of deep learning related theories, the explicit deep learning 3D reconstruction method represented by MVSNet and the implicit 3D reconstruction method represented by NeRF have been gradually developed. At the same time, the dataset and evaluation indicators for 3D reconstruction were introduced. Finally, a summary of image based 3D reconstruction was provided. [ABSTRACT FROM AUTHOR]

Experiments of a steel sphere oblique impact with a rubber cushion have been proceeded to research the variation laws of the specific energy at interface. The contact surfaces above and under the rubber cushion can be recorded with a thin carbon paper. The parameters of deformation volume and specific energy are analyzed by the developed formulas in different cases of the impact angle, cushion thickness, drop height and sphere diameter. It is found that the deformation volume and related geometrical sizes decrease approximately exponentially with the impact angle, and the volume of the tangential moving part reaches a maximum at 50° or 60°. The variation laws of the specific energy absorption/dissipation in normal are similar to that of the axis length. The tangential specific energy can be divided into three main phases, the first two appear the states of slow increase and plateau, between of them a fluctuating peak exists at 30–40°. In final phase, the energy absorption shows sharp increase, but the energy dissipation first increases and then decreases. In addition, they increase linearly with the drop height and sphere diameter, and an optimum cushion thickness of 4 or 5 mm in the given cases. [ABSTRACT FROM AUTHOR]

In this paper, we derive explicit second-order necessary and sufficient optimality conditions of a local minimizer to an optimal control problem for a quasilinear second-order partial differential equation with a piecewise smooth but not differentiable nonlinearity in the leading term. The key argument rests on the analysis of level sets of the state. Specifically, we show that if a function vanishes on the boundary and its the gradient is different from zero on a level set, then this set decomposes into finitely many closed simple curves. Moreover, the level sets depend continuously on the functions defining these sets. We also prove the continuity of the integrals on the level sets. In particular, Green's first identity is shown to be applicable on an open set determined by two functions with nonvanishing gradients. In the second part to this paper, the explicit sufficient second-order conditions will be used to derive error estimates for a finite-element discretization of the control problem. [ABSTRACT FROM AUTHOR]

The optimization of coke cost is the most significant cost-controlling factor for hot metal production. Therefore, worldwide cokemakers always have extra pressure from management to produce superior quality coke with inferior raw materials and optimal costs. Coke quality is crucial in blast furnace operation regarding cost and productivity. The quality of coke is significantly influenced by the quality of different categories, viz., prime hard coking coal, hard coking coal, soft coking coal and semi-soft coking coal of individual coals used in the coal blend. The impacts of these coals directly influence coke properties because all coals have an inherent characteristic with different coking potentials in terms of value-in-use (VIU). Also, the technological and techno-commercial change of the metallurgical coal market of today differs from past decades. Likewise, the future metallurgical coal market will vary from today's market. Therefore, a process for assessing/evaluating the coking potential of metallurgical coal shall be used for appropriate value-in-use to produce quality coke with the optimum cost. The composite coking potential methodology served the value-in-use purpose and was successfully implemented. The paper describes the significance of the value-in-use of metallurgical coal to evaluate the most economically favourable technique for producing the desired coke quality. [ABSTRACT FROM AUTHOR]

Compared to alternative descaling methods, the high-pressure water descaling technology offers cheaper costs and higher descaling rate, which has obvious advantages. As a key component, the descaling nozzle will have a direct impact on the descaling effect. Based on the detailed study of the traditional U-shaped and V-shaped grooving methods, this paper discovered a conical curve grooving method where the grooving curve shape factor lies between those of the two aforementioned methods, and established a full-scale model of the descaling nozzle. For the conical groove nozzle, numerical Computational Fluid Dynamics (CFD) simulations were performed using the shape factor of the groove curve between 0 and 1 and the throat diameter between 2.1 and 2.4 mm. It has been determined that a descaling nozzle with the shape factor between 0.75 and 0.9 has superior dynamic performance, and that when the throat diameter is between 2.3 and 2.4 mm, the nozzle has a higher outlet average velocity and a reasonable outlet flow rate. In conclusion, the dimensionless functional relationship between taper shape factor, throat diameter, nozzle outlet average velocity, effective descaling width and area is established in order to provide certain theoretical support for various production requirements of nozzles. [ABSTRACT FROM AUTHOR]

Pellet quality is one of the key technologies restricting the smelting of high proportion pellets in the blast furnace, especially the reduction swelling index of low silicon fluxed pellets. In this paper, the inhibition effect of grinding blast furnace return ore on the reduction swelling index of low silicon fluxed pellets was studied and application has been conducted in Shougang Jingtang Company. The experimental results show that the addition of 5–15% fine grinding blast furnace ore into pellet production significantly reduced the reduction swelling index of pellets from 23.5% to 14.3%. Microstructure and energy spectrum analysis shows that calcium ferrite, magnesium ferrite and liquid phase in the pellets with fine grinding blast furnace return ore increased obviously with a more uniform distributed liquid phase between hematite particles than in the basic group pellets and tended to be "homogenized". It is conducive to inhibiting the generation of ferric whiskers in the reduction process of the hematite phase, and thus contributes to the reduction of the swelling index. Since its implementation at Shougang Jingtang in 2020, this technology has yielded positive results. The fluxed pellets exhibit good quality with an alkalinity of 1.1, a SiO2 content of 2.1%, and a reduction in the swelling index from 18.1% to 16.5%. Besides, the pellet ratio into blast furnace has reached 55%, the cumulative average utilization coefficient of three 5500 m3 super-large blast furnaces is 2.43t/(m3. d), and the monthly average for a single furnace reaches 2.62t/(m3. d). Meanwhile, consumption reduction of calcium-containing flux slaked lime in fluxed pellets by 0.9% is greatly beneficial to reducing the cost of pellets and expanding the resources of pellet powder. [ABSTRACT FROM AUTHOR]

Context. Modeling the surface brightness distribution of stars is of prime importance to interpret the large amount of available interferometric, spectropolarimetric, or photometric observations. Beyond stellar physics, this is also a prerequisite to characterize exoplanets or our Galaxy. Nevertheless, this remains quite challenging for cool stars as it requires one to model the magnetohydrodynamic turbulence that develops in their convective envelope. Aims. In Paper I (Raynaud, R., Rieutord, M., Petitdemange, L., Gastine, T., & Putigny, B. 2018, A&A, 609, A124), the effect of the Coriolis acceleration on the surface heat flux has been studied by means of hydrodynamic simulations. In this paper, we aim to investigate the additional effect of dynamo magnetic fields that can be generated in the thick convective envelopes of cool stars. We focus on an envelope thickness that is representative of either a ∼0.35 M⊙ M dwarf, a young red giant star or a pre-main sequence star. Methods. We performed a parametric study using numerical magnetohydrodynamic simulations of anelastic convection in thick rotating spherical shells. The stratification in density ranges from a few tens to a few hundreds. The setup assumes a constant entropy jump between the inner and outer layers to force convection, with stress-free boundary conditions for the velocity field. The magnetic Prandtl number was systematically varied in order to vary the magnetic field intensity. For each model, we computed the azimuthally and temporally averaged surface distribution of the heat flux, and examined the leading-order effect of the magnetic field on the obtained latitudinal luminosity profile. Results. We identify three different regimes. Close to the onset of convection, while the first unstable modes tend to convey heat more efficiently near the equator, magnetic fields are shown to generally enhance the mean heat flux close to the polar regions (and the tangent cylinder). By progressively increasing the Rayleigh number, the development of a prograde equatorial jet was previously shown to make the equator darker when no magnetic field is taken into account. For moderate Rayleigh numbers, magnetic fields can instead inverse the mean pole-equator brightness contrast (which means going from a darker to a brighter equator when a dynamo sets in) and finally induce a similar regime to that found close to the onset of convection. For more turbulent models with larger Rayleigh numbers, magnetic fields alternatively tend to smooth out the brightness contrast. This general behavior is shown to be related to the quenching of the surface differential rotation by magnetic fields and remains valid regardless of the magnetic morphology. Conclusions. Mean global trends regarding the impact of rotation and magnetic fields on the surface brightness distribution of cool stars are theoretically depicted and need to be tested by future observations. This work opens the door to more detailed theoretical studies including the effect of nonaxisymmetric and time-variable surface features associated with magnetic activity. [ABSTRACT FROM AUTHOR]

Aims. Our aim in this paper is to refine the orbital and physical parameters of the HATS-2 planetary system and study transit timing variations and atmospheric composition thanks to transit observations that span more than 10 yr and that were collected using different instruments and pass-band filters. We also investigate the orbital alignment of the system by studying the anomalies in the transit light curves induced by starspots on the photosphere of the parent star. Methods. We analysed new transit events from both ground-based telescopes and NASA's TESS mission. Anomalies were detected in most of the light curves and modelled as starspots occulted by the planet during transit events. We fitted the clean and symmetric light curves with the JKTEBOP code and those affected by anomalies with the PRISM+GEMC codes to simultaneously model the photometric parameters of the transits and the position, size, and contrast of each starspot. Results. We found consistency between the values we found for the physical and orbital parameters and those from the discovery paper and ATLAS9 stellar atmospherical models. We identified different sets of consecutive starspot-crossing events that temporally occurred in less than five days. Under the hypothesis that we are dealing with the same starspots, occulted twice by the planet during two consecutive transits, we estimated the rotational period of the parent star and, in turn the projected and the true orbital obliquity of the planet. We find that the system is well aligned. We identified the possible presence of transit timing variations in the system, which can be caused by tidal orbital decay, and we derived a low-resolution transmission spectrum. [ABSTRACT FROM AUTHOR]

Context. High-precision ephemerides are not only useful in supporting space missions, but also in investigating the physical nature of celestial bodies. This paper reports an update to the orbit and rotation model of the Martian moon Phobos. In contrast to earlier numerical models, this paper details a dynamical model that fully considers the rotation of Phobos. Here, Phobos' rotation is first described by Euler's rotational equations and integrated simultaneously with the orbital motion equations. We discuss this dynamical model, along with the differences with respect to the model now in use. Aims. This work is aimed at updating the physical model embedded in the ephemerides of Martian moons, considering improvements offered by exploiting high-precision observations expected from future missions (e.g., Japanese Martian Moons exploration, MMX), which fully supports future studies of the Martian moons. Methods. The rotational motion of Phobos can be expressed by Euler's rotational equations and integrated in parallel with the equations of the orbital motion of Phobos around Mars. In order to investigate the differences between the two models, we first reproduced and simulated the dynamical model that is now used in the ephemerides, but based on our own parameters. We then fit the model to the newest Phobos ephemeris published by Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE). Based on our derived variational equations, the influence of the gravity field, the Love number, k2, and the rotation behavior were studied by fitting the full model to the simulated simple model. Our revised dynamic model for Phobos was constructed as a general method that can be extended with appropriate corrections (mainly rotation) to systems other than Phobos, such as the Saturn and Jupiter systems. Results. We present the variational equation for Phobos' rotation employing the symbolic Maple computation software. The adjustment test simulations confirm the latitude libration of Phobos, suggesting gravity field coefficients obtained using a shape model and homogeneous density hypothesis should be re-examined in the future in the context of dynamics. Furthermore, the simulations with different k2 values indicate that it is difficult to determine k2 efficiently using the current data. [ABSTRACT FROM AUTHOR]

This paper considers a two-echelon supply chain consisting of a manufacturer and a retailer in which the manufacturer faces a random production disruption risk. The manufacturer replenishes the unproduced items to fulfil the retailer's order from the secondary market at a higher price. To attract more customers, this paper considers a customer's demand dependent on product selling price, stock level, and freshness level of the fresh items. Furthermore, this paper considers preservation technology investment (PTI) to mitigate the deterioration rate of the items and carbon tax regulation to curb down carbon emissions revealed from the supply chain activities. The Stackelberg game approach with a leader–follower relationship is used considering the manufacturer as a leader and the retailer as a follower. Several theorems are developed to illustrate the concavity of the profit function and to find out the optimal solutions in which the objective is to maximize the manufacturer's total profit subject to the minimum total cost that the retailer is willing to incur. Several numerical examples are presented to illustrate the proposed models and the obtained results are compared for with and without carbon tax policy. Finally, sensitivity analysis with some key managerial insights is given to demonstrate the model. The results show that a product's freshness level influences consumers' decision to buy more, and that's why the freshness level is an important competitive tool to increase sales as well as the supply chain's total profit. [ABSTRACT FROM AUTHOR]

This paper examines equilibrium mixed strategies in unobservable Markovian queues featuring a second optional service with server vacations, where arriving customers may choose to join or balk the system. All customers arriving at the system receive the essential service, and some customers opt for the second service after the first service has been completed. Once all customers in the system have been served, the server takes the first of multiple vacations. If no customers are waiting upon from the vacation, then the server takes another vacation. In unobservable queues, arriving customers cannot know the queue length; however, the information pertaining to the server state may be available. By examining unobservable queues (fully unobservable and almost unobservable cases), it is possible to formulate an equilibrium joining strategy as well as the socially optimal probability of joining a fully unobservable queue. This paper also presents numerical examples illustrating how system parameters affect mixed equilibrium and socially optimal balking strategies. [ABSTRACT FROM AUTHOR]

The space industry is known as an economic driver for many world economies. In Iran, the acquisition of satellite technology knowledge is one of the achievements of the country's scientific and technological indicators in recent years, but the position and importance of optimal investment in this industry in Iran have been ignored. The optimal technology portfolio is one of the tools that can cover this gap and lead to better decision-making by policymakers. In this paper, the optimum technology portfolio determination regarding its goals, attributes and challenges is addressed for Iran's space industry with a hybrid quantitative–qualitative method in two short and medium-term periods. We formulate a technology portfolio selection model with these multi-objective functions: maximization of benefits in using different technologies comprising of both short and medium-term portfolios, maximizing the total summation of all Technology Readiness Levels (TRLs) of technologies, maximizing the acquisition speed for the technologies, and minimizing the acquisition risk of technologies in each portfolio. In the proposed model, the usability, acquisition cost, and complexity of each technology are considered meticulously. Also, the goal programming method is used to integrate the objective functions. Another novelty of this paper is the formulation of two portfolios with two different periods in which their corresponding inputs and outputs affect the other. This research can significantly help in directing the country's investment in the space industry, spatial ecosystem orientation, facilitating the creation of space-based businesses, improving economic growth, and also providing guidelines to improve the related policies in this area. In addition, this research can be an inspiration for other developing countries in the space industry. [ABSTRACT FROM AUTHOR]

This paper aims to develop and simulate a green automotive supply chain model (ASC) consisting of one supplier, one manufacturer, and two types of products (green and non-green) under disruption risks (DRs). The greening effort (i.e., electric vehicle production) is considered for both the supplier and the manufacturer. In our modeling, we include the local government intervention (GI) and their incentivization of manufacturers to produce greener products. Moreover, the effectiveness of centralized versus decentralized supply chain integration strategies in coping with disruption consequences was explored. A mathematical pricing model based on game theory is designed to maximize the total profit for both integrated and decentralized systems. The model examines the effects of the greening effort on the supply chain (SC) members with eight disruption scenarios, including Extra Production and Surplus Inventory. Simulating numerical examples reveals that the Extra Production type of disruption increase the profitability in different scenarios. Conversely, the Surplus Inventory disruption reduces profitability. Moreover, a channel coordination through cost sharing contract in the presence of disruption sharing was developed. GI and the cost-sharing contract increase the SC profit. The managerial implications of our findings are also discussed in this paper. [ABSTRACT FROM AUTHOR]

During hard machining, steels subjected to very high thermal and mechanical loads can result in microstructural/phase changes such as the formation of a white layer. This layer, which is often harder than the raw material, is considered detrimental to the fatigue performance and in-service life of machined parts. This paper proposes a comprehensive study of white layer formation during hard machining of steels using statistical analysis and artificial neural networks (ANN) modeling. To this end, two steals, named AISI 52100 and AISI 4340, commonly used in the manufacturing of structural machines' components and extensively studied in the last decade, have been considered in this study. First, Taguchi method combined with response surface methodology (RSM) was applied to analyze and to optimize the machining parameters regarding the white layer thickness. Second, an ANN model is developed to predict the white layer thickness during hard machining of the studied steels using a large amount of machining data. Three training algorithms were tested to find the most robust configuration. The equivalent carbon parameter was introduced for the first time in machining modeling which make the proposed ANN-based model capable of predicting the white layer thickness for different hardened steels. The results show a significant agreement between predictions and experimental results, avoiding costly experimental machining tests. [ABSTRACT FROM AUTHOR]

In this paper, we conduct a numerical simulation of a water jet-assisted machining process for a titanium alloy Ti17, with a focus on addressing the Fluid-Structure Interaction (FSI) problem arising during lubricated machining. The proposed coupling strategy employs the Smoothed Particle Hydrodynamics (SPH) free mesh method, coupled with an ordinary Lagrangian mesh. The SPH method is utilized to model the water jet, while the Lagrangian Finite Element Method (FEM) is employed to represent the workpiece and the tool. The hydrodynamic behavior of water is captured using the linear Huguenot form of the Mie-Greisen equation of state. Additionally, the Johnson-Cook constitutive law is applied to describe the thermoviscoplastic behavior of the titanium alloy. It is essential to note that thermal and mechanical effects were decoupled in this study. The investigation focuses on cutting force and chip morphology under two distinct cutting regimes: Dry Machining (DM) and Water Jet Assisted Machining, specifically with conventional lubrication (CL). The numerical simulations are compared with experimental results found in the literature, with an emphasis on cutting force and chip morphology. The obtained simulation results exhibit a favorable correlation with the experimental data. All numerical simulations were conducted using ABAQUS version 6.14. [ABSTRACT FROM AUTHOR]

Biosensors are becoming ubiquitous in the study of biomolecules, as, by modifying shape size and environment of metallic nanostructures it is now possible to engineer the field so to monitor subtle transient changes in molecular conformation at the level of a single biolayer. In this paper, we present a first step towards a polarization-resolved study of light-induced conformational changes of transmembrane proteins. We exploit a platform of self-organized gold nanorods on SiO2 substrates to enhance the infrared reflection absorption spectroscopy and to perform difference spectroscopy (i.e., spectrum under visible light ON minus spectrum under visible light OFF) on a light-sensitive transmembrane protein with simultaneous visible light illumination from the backside of the chip. The broad size distribution of nanorods allows us to probe with high sensitivity the modifications of the vibrational peaks over the entire fingerprint region. We show that it is possible to identify dissimilarities in the difference spectra, which in turn implies that we are monitoring over a broadband spectrum not only the chemical bonds with the dipole moment aligned orthogonally to our substrate/nanorod surface but also those with different orientation. [ABSTRACT FROM AUTHOR]

We analysis the noncollinear Spontaneous Parametric Down Conversion (SPDC) and compare the biphotons generated by the chirped Quasi-Phase-Matching (QPM) between the Periodically Poled Lithium Niobate (PPLN) and Periodically Poled KTiOPO4 (PPKTP) crystals. Due to the chirping of the crystals, the frequency response range of the biphotons would be greatly increased. For nonlinear SPDC, angular variation is limited (less than 0.06° in this paper), and the angle would narrow the frequency response range of the biphotons. We compare the effect of angle in PPLN crystals and PPKTP crystals for biphotons. Both the two crystals with chirped QPM, the single-cycle biphotons can be generated during noncollinear SPDC within a suitable angle range, which is favorable for wider applications in experiments. [ABSTRACT FROM AUTHOR]

Fluorescence molecular tomographic (FMT) reconstruction is commonly solved based on the Jacobian matrix, which is a first-order sensitivity matrix. Basically, using the second-order derivatives for iterative reconstruction can help improve the performance of convergence. In this paper, a reconstruction method of FMT based on the reduction of the second-order sensitivity matrix is proposed. In addition, the strategy of detectors rotation is combined into the inverse reconstruction to further improve the reconstruction quality. The reconstructed results demonstrate that the proposed method accelerates the reconstruction with high precision of inverse solutions. [ABSTRACT FROM AUTHOR]

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Copyright of Revue Française de Géotechnique is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Multiplanetary systems spanning the radius valley are ideal testing grounds for exploring the different proposed explanations for the observed bimodality in the radius distribution of close-in exoplanets. One such system is HIP 29442 (TOI-469), an evolved K0V star hosting two super-Earths and one sub-Neptune. We observed HIP 29442 with CHEOPS for a total of 9.6 days, which we modelled jointly with two sectors of TESS data to derive planetary radii of 3.410 ± 0.046, 1.551 ± 0.045, and 1.538 ± 0.049 R⊕ for planets b, c, and d, which orbit HIP 29442 with periods of 13.6, 3.5, and 6.4 days, respectively. For planet d this value deviates by more than 3σ from the median value reported in the discovery paper, leading us to conclude that caution is required when using TESS photometry to determine the radii of small planets with low per-transit signal-to-noise ratios and large gaps between observations. Given the high precision of these new radii, combining them with published RVs from ESPRESSO and HIRES provides us with ideal conditions to investigate the internal structure and formation pathways of the planets in the system. We introduced the publicly available code plaNETic, a fast and robust neural network-based Bayesian internal structure modelling framework. We then applied hydrodynamic models to explore the upper atmospheric properties of these inferred structures. Finally, we identified planetary system analogues in a synthetic population generated with the Bern model for planet formation and evolution. Based on this analysis, we find that the planets likely formed on opposing sides of the water iceline from a protoplanetary disk with an intermediate solid mass. We finally report that the observed parameters of the HIP 29442 system are compatible with a scenario where the second peak in the bimodal radius distribution corresponds to sub-Neptunes with a pure H/He envelope and with a scenario with water-rich sub-Neptunes. [ABSTRACT FROM AUTHOR]

Context. Asteroids preserve important information about the origin and evolution of the Solar System. Three-dimensional (3D) surface models of asteroids are essential for exploration missions and scientific research. Regular methods for 3D surface reconstruction of asteroids, such as stereo-photogrammetry (SPG), usually struggle to reconstruct textureless areas and can only generate sparse surface models. Stereo-photoclinometry (SPC) can reconstruct pixel-wise topographic details but its performance depends on the availability of images obtained under different illumination conditions and suffers from uncertainties related to surface reflectance and albedo. Aims. This paper presents Asteroid-NeRF, a novel deep-learning method for 3D surface reconstruction of asteroids that is based on the state-of-the-art neural radiance field (NeRF) method. Methods. Asteroid-NeRF uses a signed distance field (SDF) to reconstruct a 3D surface model from multi-view posed images of an asteroid. In addition, Asteroid-NeRF incorporates appearance embedding to adapt to different illumination conditions and to maintain the geometric consistency of a reconstructed surface, allowing it to deal with the different solar angles and exposure conditions commonly seen in asteroid images. Moreover, Asteroid-NeRF incorporates multi-view photometric consistency to constrain the SDF, enabling optimised reconstruction. Results. Experimental evaluations using actual images of asteroids Itokawa and Bennu demonstrate the promising performance of Asteroid-NeRF, complementing traditional methods such as SPG and SPC. Furthermore, due to the global consistency and pixel-wise training of Asteroid-NeRF, it produces highly detailed surface reconstructions. Asteroid-NeRF offers a new and effective solution for high-resolution 3D surface reconstruction of asteroids that will aid future exploratory missions and scientific research on asteroids. [ABSTRACT FROM AUTHOR]

Context. Many novel methods have been proposed to mitigate stellar activity for exoplanet detection as the presence of stellar activity in radial velocity (RV) measurements is the current major limitation. Unlike traditional methods that model stellar activity in the RV domain, more methods are moving in the direction of disentangling stellar activity at the spectral level. As deep neural networks have already been proven to be one of the most effective tools in data mining, in this work, we explore their potential in the context of Earth-like planet detection in RV measurements. Aims. The goal of this paper is to present a novel convolutional neural network-based algorithm that efficiently models stellar activity signals at the spectral level, enhancing the detection of Earth-like planets. Methods. Based on the idea that the presence of planets can only produce a Doppler shift at the spectral level while the presence of stellar activity can introduce a variation in the profile of spectral lines (asymmetry and depth change), we trained a convolutional neural network to build the correlation between the change in the spectral line profile and the corresponding RV, full width at half maximum (FWHM) and bisector span (BIS) values derived from the classical cross-correlation function. Results. This algorithm has been tested on three intensively observed stars: Alpha Centauri B (HD 128621), Tau ceti (HD 10700), and the Sun. By injecting simulated planetary signals at the spectral level, we demonstrate that our machine learning algorithm can achieve, for HD 128621 and HD 10700, a detection threshold of 0.5 m s−1 in semi-amplitude for planets with periods ranging from 10 to 300 days. This threshold would correspond to the detection of a ~4 M⊕ in the habitable zone of those stars. On the HARPS-N solar dataset, thanks to significantly more data, our algorithm is even more efficient at mitigating stellar activity signals and can reach a threshold of 0.2 m s−1, which would correspond to a 2.2 M⊕ planet on the orbit of the Earth. Conclusions. To the best of our knowledge, it is the first time that such low detection thresholds are reported for the Sun, but also for other stars, and therefore this highlights the efficiency of our convolutional neural network-based algorithm at mitigating stellar activity in RV measurements. [ABSTRACT FROM AUTHOR]

Context. The solar energetic particle analysis platform for the inner heliosphere (SERPENTINE) project, funded through the H2020-SPACE-2020 call of the European Union's Horizon 2020 framework program, employs measurements of the new inner heliospheric spacecraft fleet to address several outstanding questions on the origin of solar energetic particle (SEP) events. The data products of SERPENTINE include event catalogs, which are provided to the scientific community. Aims. In this paper, we present SERPENTINE's new multi-spacecraft SEP event catalog for events observed in solar cycle 25. Observations from five different viewpoints are utilized, provided by Solar Orbiter, Parker Solar Probe, STEREO A, BepiColombo, and the near-Earth spacecraft Wind and SOHO. The catalog contains key SEP parameters for 25–40 MeV protons, ~1 MeV electrons, and ~100 keV electrons. Furthermore, basic parameters of associated flares and type II radio bursts are listed, as are the coordinates of the observer and solar source locations. Methods. An event is included in the catalog if at least two spacecraft detect a significant proton event with energies of 25–40 MeV. The SEP onset times were determined using the Poisson-CUSUM method. The SEP peak times and intensities refer to the global intensity maximum. If different viewing directions are available, we used the one with the earliest onset for the onset determination and the one with the highest peak intensity for the peak identification. We furthermore aimed to use a high time resolution to provide the most accurate event times. Therefore, we opted to use a 1-min time resolution, and more time averaging of the SEP intensity data was only applied if necessary to determine clean event onsets and peaks. Associated flares were identified using observations from near Earth and Solar Orbiter. Associated type II radio bursts were determined from ground-based observations in the metric frequency range and from spacecraft observations in the decametric range. Results. The current version of the catalog contains 45 multi-spacecraft events observed in the period from November 2020 until May 2023, of which 13 events were found to be widespread (observed at longitudes separated by at least 80° from the associated flare location) and four could be classified as narrow-spread events (not observed at longitudes separated by at least 80° from the associated flare location). Using X-ray observations by GOES/XRS and Solar Orbiter/STIX, we were able to identify the associated flare in all but four events. Using ground-based and space-borne radio observations, we found an associated type II radio burst for 40 events. In total, the catalog contains 142 single event observations, of which 20 (45) have been observed at radial distances below 0.6 AU (0.8 AU). It is anticipated that the catalog will be extended in the future. [ABSTRACT FROM AUTHOR]

Context. Understanding the effects of rotation in stellar evolution is key to modelling early-type stars, half of which have equatorial velocities over 100 km s−1. The nearby star Altair is an example of such fast-rotating stars, and furthermore, it has the privilege of being modelled by a detailed 2D concordance model that reproduces most of its observables. Aims. The aim of this paper is to include new asteroseismic frequencies to improve our knowledge of Altair, especially its age. Methods. We processed images of Altair obtained during July 2022 by the Transiting Exoplanet Survey Satellite using the halo photometry technique to obtain its light curve over this observation period. Results. By analysing the light curve, we derived a set of 22 new frequencies in the oscillation spectrum of Altair and confirmed 12 previously known frequencies. Compared with model predictions, we could associate ten frequencies with ten axisymmetric modes. This identification is based on the modelled visibility of the modes. Moreover, nine of the modelled frequencies can be adjusted to simultaneously match their corresponding observed frequencies, once the core hydrogen mass fraction of the concordance model is set to Xcore/Xini ≃ 0.972, with Xini = 0.739. Using the combined results of a 1D MESA model computing the pre-main sequence and a 2D time-dependent ESTER model computing the main sequence, we find that this core hydrogen abundance sets the age of Altair to 88 ± 10 Myr, which is slightly younger than previous estimates. [ABSTRACT FROM AUTHOR]

Context. Binary pulsars are a powerful tool for probing strong gravity that still outperform direct gravitational wave observations in a number of ways due to the remarkable accuracy of the pulsar timing. They can constrain the presence of additional charges of the orbiting neutron stars very precisely, leading to new channels of energy and angular momentum loss, such as scalar dipole radiation. Aims. In the present paper, we explore in detail the possibility of constraining different classes of scalar-Gauss-Bonnet gravity with binary pulsars. Additionally, we updated the existing constraints related to the observed maximum mass of neutron stars. Methods. Interestingly, depending on the equation of state, the resulting limits on the theory coupling parameters can outperform the constraints coming from binary merger observations by up to a factor of two, even for so-called Einstein-dilaton-Gauss-Bonnet gravity where neutron stars are often underestimated as relevant theory probes. As an additional merit, precise Bayesian methods are compared with approximate approaches, with the latter showing a very good performance despite their simplicity. [ABSTRACT FROM AUTHOR]

Context. V892 Tau is a young binary star surrounded by a circumbinary disc that shows hints of an interaction with the low-mass nearby star V892 Tau NE. Aims. The goal of this paper is to constrain the orbit of V892 Tau NE and to determine the resulting circumbinary disc dynamics. Methods. We present new ALMA observations of the V892 Tau circumbinary disc at a twice higher angular and spectral resolution. We modelled the data with V892 Tau as a triple system and performed a grid of hydrodynamical simulations testing several orbits of the companion. The simulation outputs were then post-processed to build synthetic maps that we compared to the observations. Results. The 12CO emission of the disc shows clear non-Keplerian features such as spiral arms. When comparing the data with our synthetic observations, we interpreted these features as ongoing interactions with the companion. Our simulations indicate that an eccentricity of e ~ 0.5 of the companion is needed to reproduce the observed disc extent and that a mutual inclination of ∆i ~ 60° with the inner binary reproduces the measured disc tilt. Conclusions. In order to explain most of the features of the circumbinary disc, we propose that V892 Tau NE follows an orbit with a mild eccentricity 0.2 < e < 0.5 and a mutual inclination of 30° < ∆i < 60°. Such a misaligned companion suggests the disc is oscillating and precessing with time, stabilising in an intermediate plane with a non-zero mutual inclination with the inner binary. Given the orbital configuration, we show that the stability of future planets is compromised in the second half of the disc once the gas has dissipated. [ABSTRACT FROM AUTHOR]

Context. This is the second paper in a series presenting the results from a 500 h−1Mpc large constrained simulation of the local Universe (SLOW). The initial conditions for this cosmological hydro-dynamical simulation are based on peculiar velocities derived from the CosmicFlows-2 catalog. The simulation follows cooling, star formation, and the evolution of super-massive black holes. This allows one to directly predict observable properties of the intracluster medium (ICM) within galaxy clusters, including X-ray luminosity, temperatures, and the Compton-y signal. Aims. Comparing the properties of observed galaxy clusters within the local Universe with the properties of their simulated counterparts enables us to assess the effectiveness of the initial condition constraints in accurately replicating the mildly nonlinear properties of the largest, collapsed objects within the simulation. Methods. Based on the combination of several, publicly available surveys we compiled a sample of galaxy clusters within the local Universe, of which we were able to cross-identify 46 of them with an associated counterpart within the SLOW simulation. We then derived the probability of the cross identification based on mass, X-ray luminosity, temperature, and Compton-y by comparing it to a random selection. Results. Our set of 46 cross-identified local Universe clusters contains the 13 most massive clusters from the Planck SZ catalog as well as 70% of clusters with M500 larger than 2 × 1014 M⊙. Compared to previous constrained simulations of the local volume, we found in SLOW a much larger amount of replicated galaxy clusters, where their simulation-based mass prediction falls within the uncertainties of the observational mass estimates. Comparing the median observed and simulated masses of our cross-identified sample allows us to independently deduce a hydrostatic mass bias of (1 − b)≈0.87. Conclusions. The SLOW constrained simulation of the local Universe faithfully reproduces numerous fundamental characteristics of a sizable number of galaxy clusters within our local neighborhood, opening a new avenue for studying the formation and evolution of a large set of individual galaxy clusters as well as testing our understanding of physical processes governing the ICM. [ABSTRACT FROM AUTHOR]

Context. The extragalactic background light (EBL) carries a huge astrophysical and cosmological content. Its frequency spectrum and redshift evolution are determined by the integrated emission of unresolved sources, with these being galaxies, active galactic nuclei, or more exotic components. The near-UV region of the EBL spectrum is currently not well constrained, yet a significant improvement can be expected thanks to the soon-to-be launched Ultraviolet Transient Astronomy Satellite (ULTRASAT). Intended to study transient events in the 2300–2900 Å observed band, this detector will provide wide field maps tracing the UV intensity fluctuations at the largest scales. Aims. In this paper, we suggest how to exploit the ULTRASAT full-sky map as well as its low-cadence survey in order to reconstruct the redshift evolution of the UV-EBL volume emissivity. We build upon the work of Chiang et al. (2019, ApJ, 870, 120), who used the clustering-based redshift (CBR) technique to study diffuse light maps from GALEX. Their results showed the capability of the cross correlation between GALEX and SDSS spectroscopic catalogs in constraining UV emissivity, highlighting how CBR is sensitive only to extragalactic emissions, avoiding foregrounds and Galactic contributions. Methods. In our analysis, we introduce a framework to forecast the CBR constraining power when applied to ULTRASAT and GALEX in cross correlation with the five-year DESI spectroscopic survey. Results. We show that these will yield a strong improvement in the measurement of the UV-EBL volume emissivity. For λ = 1500 Å non-ionizing continuum below z ∼ 2, we forecast a 1σ uncertainty ≲26% (9%) with conservative (optimistic) bias priors using the ULTRASAT full-sky map. Similar constraints can be obtained from its low-cadence survey, which will provide a smaller but deeper map. Finally, we discuss how these results will foster our understanding of UV-EBL models. [ABSTRACT FROM AUTHOR]

Context. The measurement of pulsar pulse times-of-arrival (ToAs) is a crucial step in detecting low-frequency gravitational waves. To determine ToAs, we can use template-matching to compare each observed pulse profile with a standard template. However, using different combinations of templates and template-matching methods (TMMs) without careful consideration can lead to inconsistent results. Aims. In pulsar timing array (PTA) experiments, distinct ToAs from the same observations can be obtained due to the use of diverse templates and TMMs. In other words, employing diverse approaches can yield different timing results and would thus have a significant impact on subsequent gravitational wave searches. In this paper we examine several commonly used combinations to analyze their effect on pulse ToAs. Methods. We evaluated the potential impact of template and TMM selection on 13 typical millisecond pulsars within the European PTA. We employed pulsar timing methods, specifically the root mean square and reduced chi-square (χ2r) of the residuals of the best timing solution, to assess the outcomes. Additionally, we evaluated the system-limited noise floor (SLNF) for each pulsar at various telescopes operating around 1.4 GHz using frequency-resolved templates. Results. Our findings suggest that utilizing data-derived and smoothed templates in conjunction with the Fourier-domain with Markov chain Monte Carlo TMM is generally the most effective approach, though there may be exceptions that require further attention. Furthermore, we determine that pulse phase jitter noise does not significantly limit the current precision of the European PTA's timing, as jitter levels derived from other studies are much lower than the SLNF. [ABSTRACT FROM AUTHOR]

Context. The third data release of Gaia, in June 2022, included the first large sample of sparse photometric data for more than 150 000 Solar System objects (SSOs), mainly asteroids. Aims. The SSO photometric data can be processed to derive information on the physical properties for a large number of objects, including spin properties, surface photometric behaviour in a variety of illumination conditions, and overall shape. Methods. After selecting a set of 22 815 objects for which an adequate number of accurate photometric measurements had been obtained by Gaia, we applied the 'genetic' algorithm of photometric inversion developed by the Gaia Data Processing and Analysis Consortium to process SSO photometric data. Given the need to minimise the required data processing time, the algorithm was set to adopt a simple triaxial ellipsoid shape model. Results. Our results show that in spite of the limited variety of observing circumstances and the limited numbers of measurements per object at present (in the majority of cases no greater than 40 and still far from the number expected at the end of the mission of about 60–70), the proportion of correct determinations for the spin period among the observed targets is about 85%. This percentage is based on a comparison with reliable literature data following a moderate filtering procedure developed to remove dubious solutions. Conclusions. The analysis performed in this paper is important in the context of developing further improvements to the adopted data reduction procedure. This includes the possible development of better solution filtering procedures that take into account, for each object, the possible presence of multiple, equivalent spin period solutions that have not been systematically investigated in this preliminary application. [ABSTRACT FROM AUTHOR]