bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling of mechanical characteristics of composite materials applied for protection of information and control complexes of aircraft
Authors: Markov A V , Oreshina O A 
Published: July 2021

Abstract
In modern conditions of electronic warfare, effective protection of information and control complexes of aircraft (AC) from the destructive effects of external interference is impossible without the use of innovative solutions in the field of creating new composite materials (CM) with radio-absorbing properties. This scientific area is inextricably linked with the issues of predicting the properties of these materials. A wide variety of design solutions to protect aircraft “electronics”, as well as a wide range of electromagnetic and mechanical effects, require the creation of functional materials for specific operating conditions. Thus, the developers of functional materials must have an effective tool to predict the properties of the CM being created. Solutions can be based on mathematical models that allow predicting the properties of CM and subsequently optimizing their composition. The article discusses the identification and verification of mathematical models of the mechanical characteristics of CMs based on BASF polyurethane with the addition of both untreated and processed ferric iron oxide as a filler, with subsequent optimization of the characteristics and determination of the corresponding CM composition with radio-absorbing properties. Experimental studies have been carried out, which confirm the adequacy of the developed mathematical models.
A review of Hybrid/combined methods for trajectory optimization of flight vehicles
Authors: Nguyen P 
Published: July 2021

Abstract
This work aims to review the proposed trajectory optimization algorithms and their applications in solving flight trajectory planning and optimal control problems. Beside the classification of trajectory optimization algorithms listed in Chai R, Savvaris A, Tsourdos A and Chai S such as the deterministic; the stochastic; and the multi-objective algorithms, this work adds in reviewing the effective and frequently-used approach for solving optimal problems— the hybrid/combined methods. The results of related works show that this hybrid approach is effective and can provide feasible solutions for solving the flight vehicle trajectory optimal design and control problems.
Finite-state machine method in the safety assessment process using Stateflow diagrams
Authors: Savelev A S , Eroshchenkov E V , Neretin E S , Shevela D A 
Published: July 2021

Abstract
Safety Assessment Process is one of the most important processes of the avionics systems design. Modern and perspective aircraft uses a Model-Based Design approach, but Safety Assessment performing with a high risk of error due to human factors. Nowadays design tools, like MATLAB Simulink and ANSYS medini analyze, propose new methods of the safety assessment process—Model-Based Safety Assessment. (MBSA). The types of MBSA were analyzed and classified. This work describes the MBSA approach in general and focuses on MBSA in part of the failure modeling using the finite-state machine method. The use of this method can help both the safety team and development team to have a clear dialogue about the system’s work and failures.
Design of beam optics for a Super Tau-Charm Factory
Authors: Lan J.Q. , Luo Q. , Zhang C. , Gao W.W. , Xu Y. , Bai Y. 
Published: July 2021

Abstract
Beam optics design for a Super Tau-Charm Factory (STCF) that
planning in China is presented in this paper. This STCF is an
electron-positron circular collider characterized with high
luminosity, wide energy ranges as well as high longitudinally
polarized electron beam. In order to achieve high luminosity, the
recently proposed collision scheme based on large Piwinski angle and
crab waist sextupole will be adopted. In this paper, the beam
optical parameters and their design basis for the STCF storage ring
lattice are given. In addition, the preliminary dynamic aperture and
beam-beam simulation are studied to get a luminosity more than
0.5 × 1035 cm-2 s-1 at the optimized
energy 2 GeV.
Evaluation of soil carbon dynamics after forest cover change in CMIP6 land models using chronosequences
Authors: Boysen Lena R , Brovkin Victor , Wårlind David , Peano Daniele , Lansø Anne Sofie , Delire Christine , Burke Eleanor , Poeplau Christopher , Don Axel 
Published: July 2021

Abstract
Land surface models are used to provide global estimates of soil organic carbon (SOC) changes after past and future change land use change (LUC), in particular re-/deforestation. To evaluate how well the models capture decadal-scale changes in SOC after LUC, we provide the first consistent comparison of simulated time series of LUC by six land models all of which participated in the coupled model intercomparison project phase 6 (CMIP6) with soil carbon chronosequences (SCCs). For this comparison we use SOC measurements of adjacent plots at four high-quality data sites in temperate and tropical regions. We find that initial SOC stocks differ among models due to different approaches to represent SOC. Models generally meet the direction of SOC change after reforestation of cropland but the amplitude and rate of changes vary strongly among them. The normalized root mean square errors of the multi model mean range from 0.5 to 0.8 across sites and 0.1–0.7 when excluding outliers. Further, models simulate SOC losses after deforestation for crop or grassland too slow due to the lack of crop harvest impacts in the models or an overestimation of the SOC recovery on grassland. The representation of management, especially nitrogen levels is important to capture drops in SOC after land abandonment for forest regrowth. Crop harvest and fire management are important to match SOC dynamics but more difficult to quantify as SCC rarely report on these events. Based on our findings, we identify strengths and propose potential improvements of the applied models in simulating SOC changes after LUC.
The impact of groundwater depletion on agricultural production in India
Authors: Bhattarai Nishan , Pollack Adrienne , Lobell David B , Fishman Ram , Singh Balwinder , Dar Aaditya , Jain Meha 
Published: July 2021

Abstract
India relies on groundwater irrigation to produce staple grain crops that provide over half of the calories consumed by its over 1.3 billion people. While groundwater has helped India achieve grain self-sufficiency, aquifers have been overexploited across much of the country and its implications for crop production are unclear. To understand how groundwater depletion affects staple grain (wheat, rice, maize, pearl millet, and sorghum) production in India, we ran district-level panel regressions using agricultural census, groundwater observation, and gridded weather datasets over a ten-year study period (2004–2013). We find that nationally, declining groundwater levels are associated with significant reductions in yield, cropped area, and production for wheat, rice, and maize in the winter season. Despite the negative impacts of groundwater depletion on crop production, we find little evidence that farmers are switching from planting more water-intensive to less water-intensive grains. Using profit-based decision modeling, we further investigated the effects of agricultural energy prices on crop choice in the monsoon season across Haryana and Punjab, which are responsible for over 60% of India’s grain production, have high electricity subsidies, and have rapidly depleting water tables. We find that eliminating energy subsidies for groundwater pumping would likely not encourage farmers to switch to planting less water-intensive crops, though sensitivity analyses suggest that it could encourage the adoption of increased water conservation efforts. In summary, our analyses reveal a discernable impact of groundwater depletion on crop production in India and suggest that reducing or removing energy subsidies may largely affect water use but not crop choice.
Assessment of groundwater well vulnerability to contamination through physics-informed machine learning
Authors: Soriano Mario A , Siegel Helen G , Johnson Nicholaus P , Gutchess Kristina M , Xiong Boya , Li Yunpo , Clark Cassandra J , Plata Desiree L , Deziel Nicole C , Saiers James E 
Published: July 2021

AbstractContamination from anthropogenic activities is a long-standing challenge to the sustainability of groundwater resources. Physically based (PB) models are often used in groundwater risk assessments, but their application to large scale problems requiring high spatial resolution remains computationally intractable. Machine learning (ML) models have emerged as an alternative to PB models in the era of big data, but the necessary number of observations may be impractical to obtain when events are rare, such as episodic groundwater contamination incidents. The current study employs metamodeling, a hybrid approach that combines the strengths of PB and ML models while addressing their respective limitations, to evaluate groundwater well vulnerability to contamination from unconventional oil and gas development (UD). We illustrate the approach in northeastern Pennsylvania, where intensive natural gas production from the Marcellus Shale overlaps with local community dependence on shallow aquifers. Metamodels were trained to classify vulnerability from predictors readily computable in a geographic information system. The trained metamodels exhibited high accuracy (average out-of-bag classification error <5%). A predictor combining information on topography, hydrology, and proximity to contaminant sources (inverse distance to nearest upgradient UD source) was found to be highly important for accurate metamodel predictions. Alongside violation reports and historical groundwater quality records, the predicted vulnerability provided critical insights for establishing the prevalence of UD contamination in 94 household wells that we sampled in 2018. While <10% of the sampled wells exhibited chemical signatures consistent with UD produced wastewaters, >60% were predicted to be in vulnerable locations, suggesting that future impacts are likely to occur with greater frequency if safeguards against contaminant releases are relaxed. Our results show that hybrid physics-informed ML offers a robust and scalable framework for assessing groundwater contamination risks.
Biological control of Sclerotium rolfsii on tomato seedlings using Bacillus spp. consortium
Authors: Yanti Y , Hamid H , Yaherwandi Reflin 
Published: July 2021

Abstract
The Sclerotium rolfsii which widely distributed soil-borne plant pathogen, causes many economically important crops severely reduce their yield at worldwide extend, including tomato and are very difficult to control due to its sclerotia. The beneficial plant-microbe interactions play crucial roles in protection against large number of plant pathogens causing disease. Our previous research had screened 9 Bacillus spp. strains which had ability to control R. syzigii subsp. indonesiensis and promote growth and yield of solanaceous plants. Those strains were Bacillus cereus AGBE 1.2 TL, Bacillus toyonensis AGB E 2.1 TL, Bacillus cereus SLB E 1.1 SN, Bacillus cereus SLB E 1.1 AP, Bacillus pseudomycoides SLB E 3.1 AP, Bacillus cereus SLB E 1.1 BB, Bacillus cereus SLB E 2.1 BB, Bacillus thuringiensis SLB E 2.3 BB, and Bacillus cereus SLB E 3.1 BB. Our current study objective was to develop the best consortium to control S. rolfsii and promote growth of S. rolfsii seedlings. The research designed in experimental methods and was arranged in a completely randomized design with 7 treatments and triplications. The methods done were compatibility assay of the Bacillus strains, development of consortium based from the compatibility, and consortium assay to control S. rolfsii and promote growth of tomato seedlings. The result showed, out of the 6 compatible consortiums, consortium A4 consists of Bacillus strain AGBE 1.2 TL, SLBE 3.1 AP, SLBE 2.1 BB and SLBE 3.1 BB were shown to be the best to control S. rolfsii on tomato seedlings with 85.00% of the seedlings were shown no symptoms. The consortium also had the best ability to promote growth of tomato seedlings up to 25.00% compared with control.
Probing the balance of Telechelic Polymers Bridging and Screened-Coulomb Interactions in Microemulsion System
Authors: Ahfir R , Elkhaoui S , Khatouri M , Lemaalem M , Talha L , Filali M 
Published: July 2021

Abstract
The structural properties of neutral oil-in-water (O/W) microemulsions nanodroplets in the presence of telechelic polymers PEO modified with two hydrophobic end functions (PEO- 2m) were studied by Small-Angle Neutron Scattering (SANS). We show that the unknown attractive interaction introduced by the addition of PEO-2m, can could be balanced by a known repulsion interaction due to the addition of a cationic surfactant Cp +, which causes a progressive transformation of the bridges connecting the nanodroplets into loops. For this, we compute the structure factor S(q) with an effective pair potential, using the Ornstein Zernicke (OZ) integral equation approach with the Hypernetted Chain (HNC) closure relation. Generally, the agreement between the neutron scattering spectra and the numerical study is reasonable and allows a detailed description for each sample.
An approach to determine the diatomic vibrational energy levels: application to LiH, NO and CO molecules
Authors: Amila I , Idrissi M Janati , Fedoul A , Sayouri S 
Published: July 2021

Abstract
This work presents the systematic calculation of vibrational energy levels, for diatomic molecules through an alternative approach, reposed on the Floquet representation analysis. The Morse potential function has been employed to solve the Schrodinger equation, and to obtain the vibrational energy levels of diatomic systems. As an illustration, the numerical energy values of some molecules have been computed, and compared to those of literature, revealing a good agreement, and showing the accuracy of our approach.
Sol-gel synthesis and structural study of a lithium titanate phase Li 3xLa 2/3.x □1/3-2x TiO3 as solid electrolyte
Authors: Chouiekh Abdelhak , Naji Mohamed , Rjeb Abdelilah , Ababou Yahya , Sayouri Salaheddine 
Published: July 2021

Abstract
Perovskite lithium lanthanum titanate (LLTO) was prepared as an inorganic solid electrolyte material for lithium ion batteries applications using sol-gel method. Three different compositions of : (a) 3x=0.3 (Li 0.3La 0.57TiO3), (b) 3x=0.5 (Li 0.5La 0.5TiO3) were prepared and calcined at 1000°C for 6h, and (c) 3x=0.1 (Li 0.1La 0.63TiO3) prepared and calcined at 1100°C for 6h. The effects of lithium content and calcination temperature on the structure of the perovskite powders were studied. The synthesized powders were characterized by X-ray diffraction analysis. Results indicate that the Li 0.3La 0.57TiO3 was crystallized in tetragonal structure of space group P4/mmm. On the other hand, Rietveld refinement analysis for the LLTO samples confirmed the formation of the Li 0.3La 0.57TiO3 crystalline phase in the tetragonal P4/mmm space group, the Li 0.5La 0.5TiO3 phase in the tetragonal P4/mmm space group, and Li 0.1La 0.63TiO3 phase in orthorhombic Pmmm space group.
Structural and optical properties of CdO-ZnO thin films synthesized by sol-gel spin coating method
Authors: Nfissi A , Belhajji M , Mrharrab L , Ababou Y , Sayouri S 
Published: July 2021

Abstract
CdO-ZnO thin films with volume ratio of (Cd: Zn) of (1: 0), (0.75: 0.25), (0.5: 0.5) and (0: 1) were prepared using the sol-gel spin coating method. The as-coated films were annealed at 550 °C for 1 h and their structural and optical properties investigated. From structural investigations, it was observed that ZnO phase is present in the composites. The crystallite size values decreased with increasing the Zn content, and the dislocation density increased from 0.77 to 0.988 (1015 lines/m 2). The optical properties were examined by a ultraviolet-Visible spectroscopy, which indicated that the optical transmission increases in the visible region, and the band gap is found to be blue shift from 2.26 to 3.24 eV with the increase of ZnO content.
Influence of fillers on the properties of under-rail gaskets
Authors: Adylkhodzhaev A I , Tsoy V M , Kondrashchenko V I 
Published: July 2021

Abstract
Using the criterion of the reduced hydration activity of inorganic materials, the choice of magnetic separation waste as a mineral filler for the production of under-rail gaskets is justified. By the methods of experimental planning, mathematical models were obtained that adequately describe the hardness (Shore A) and the conditional tensile strength of the gasket material, using which the composition of the material was developed that exceeds the physical and technical characteristics of the production composition.
Investigation of the influence of elastic-mass characteristics of the axle test stand links on its own oscillation frequencies
Authors: Raksha S , Anofriev P , Kuropiatnyk O , Plitchenko S 
Published: July 2021

Abstract
The reliability of work according to the criteria of vibration stability of the stand for testing the axles of wheelsets for endurance is largely determined by the natural vibration frequencies of the stand. The work considers a stand with a lever structure for loading the tested axles. In order to determine the influence of the parameters of the cross-section of the links on the natural frequencies of the vibration stand, the frequency characteristics were obtained by the method of mathematical modeling for two variants of the design schemes of the stand. Studies have shown that increasing the cross-sectional area of the levers without measuring other linear dimensions leads to a simultaneous increase in their mass and cruelty. The rigidity of the levers is defined as for beams on two supports with a load of a transverse concentrated force. As a result, the calculated values of the natural frequencies of the stand vibrations change insignificantly. A deeper analysis of the Eigen frequency characteristics of the stand with the tools of the Matlab system made it possible to obtain linear regression equations with the coefficients of determination close to one. The obtained research results gave reason to expect a decrease in stresses in the metal structures of the stand with an increase in the cross-sectional area of the levers, however, the values of the natural frequencies of the stand vibrations vary within a few percent. The way to control the natural frequencies of the stand vibrations only by changing the profile parameters is ineffective.
Perpendicular to steel reinforcing bars axis displacements of rebars for determination the torsional stiffness of reinforced concrete elements with normal cracks
Authors: Azyzov T , Kochkarev D , Tsyhanenko L , Tsyhanenko H , Srybniak N 
Published: July 2021

Abstract
The article provides a technology for determining the displacement of the end of the reinforcing bar embedded in concrete for measuring the shifting force in the longitudinal reinforcement. Dependences of the displacement of the end of the reinforcing bar on different protective layers are shown. A formula to define the displacement of steel reinforcing bars due to the shifting force is given. The formula was obtained by the numerical computation approximation using three-dimensional finite elements. A method for determining the torsional stiffness of reinforced concrete element with normal crack is presented. In this method the pliability of the reinforcement perpendicular to its axis is also considered.
Calculation of a multi-span frame for stability
Authors: Balduk P , Balduk H , Yaremenko O , Yaremenko N 
Published: July 2021

Abstract
The loss of stability of the first kind as applied to the longitudinal bending of the supports of a flat one-story free multispan frame under the action of vertical forces is considered. The elements of the frame have arbitrary stiffnesses constant along the length of the elements. The system of nonlinear equations of displacement method is solved. The matrix of coefficients of the system of equations is presented in block form. Formulas of generalized coefficients for each block of matrix are determined, and then one or another element of general stability equation matrix. A slight correction of generalized coefficients formulas makes it possible to extend the methodology to calculate the stability of non-free frames (overpasses). Compact notation of generalized coefficients of stability equation matrix makes it possible to considerably simplify development of algorithms and computer programs designed for solution of such tasks. The algorithm is implemented in Excel. To verify the obtained results, test calculations of stability frames for which the exact solution is known have been performed. Stability calculation of plane frame of periodic structure has been done by the suggested method. The diagram of the boundary curve has been made and the areas of frame stability and instability under the action of the given system of forces have been determined. Stability calculations of the model in the software package ANSYS, with subsequent comparison of the calculation results, have been performed.
Nonlinear problems of equilibrium for axisymmetric membranes
Authors: Bedov A , Vagapov R , Gabitov A , Salov A 
Published: July 2021

Abstract
The problems for equilibrium of circular and annular membranes made of elastic-orthotropic and elastoplastic isotropic materials are considered in this paper in a geometrically and physically nonlinear formulation meeting the Föppl-Karman assumptions. The outer contour is considered to be stationary, while the inner one being free, or reinforced by either an elastic ring or a fixed disk. The load is assumed to be uniformly distributed over the membrane surface.
The results of calculations of circular and annular membranes with large deflections in comparison with thickness, deformations and squares of angular displacement to be comparable with each other but small in comparison with the unit are presented in the first part thereof. The resulting boundary value problems are reduced to the Cauchy problem to be numerically integrated by the shooting method under the iterative Steffensen algorithm. For circular membrane structures an analytical solution as a power series similar to the Prescott series for a circular membrane is assumed either.
The results of numerical solutions of problems are presented as dimensionless characteristic functions. Analysis of this information will enable to solve the problem of the support, being optimal in a certain sense when the membrane is close to be equal in strength.
Problems of elastoplastic equilibrium of isotropic membranes are presented in the second part thereof. The idealized Prandtl diagram is used as the main characteristic of the mechanical properties of the membrane material. The Tresca-Sant-Venant and Huber-Mises-Hencky conditions were used as criteria for the transition of a material from an elastic state to a plastic one. Solutions of physically nonlinear equilibrium problems for axisymmetric membranes are also presented as dimensionless characteristic functions.