bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ho-Mn co-doping in barium titanate piezoceramics via sol-gel process followed by microwave and conventional heating
Authors: Akbari M , Heidaryan A , Shokrollahi H , Mirzaee O 
Published: June 2023

Abstract
Co-doped barium titanate (BT) piezoceramics are applied in advanced energy harvesting systems. In the present study, Ba1−2xHo2xTi1−xMnxO3 (x = 0, 0.02, 0.04, and 0.06) were produced via the sol-gel-assisted solid state co-doping technique followed by microwave and conventional heating. In the current investigation, the synthesizing and phase characterization, allotropic transition, morphological examination, elemental analysis and dielectric-piezoelectric responses were investigated by x-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermo-Gravimetric Analysis (TGA), Field-Emission Sanning Electron Microscope (FESEM), Energy-Dispersive x-ray Spectroscopy (EDS), Mapping analysis and inductance-Capacitance-Resistance meter (LCR meter) techniques, respectively. The XRD pattern and DSC/ TGA outcomes demonstrated that tetragonal BT phases without minor BaCO3 secondary phases are synthesized properly, and that the negligible unsolicited BaCO3 phases are thoroughly calcined by a microwave at 900 °C. Doping resulted in an increase in tetragonality (c/a) of 0.19%, 0.15%, and 0.04%, respectively, compared to the pure calcined BT. Additionally, the crystallite size of BT decreased significantly by 59%, 58%, and 52%, respectively. The results revealed that the microwave-sintered samples have higher purity, drastic delicate and finer grain size distribution, and superior tetragonality with respect to the conventionally sintered furnace samples. Furthermore, the piezoelectric constant for the microwave sintered and the conventionally sintered samples with the same value of x = 0.04 were 390 and 370 (pC/N), respectively, which established that the sintering method has satisfactory affection (approximately 6%) on the piezo function of the samples. Eventually, the prepared samples which had 0, 2, 4, and 6% moles of Ho3+-Mn2+ cations and were sintered by a microwave compared to the similar specimens fabricated by the furnace had superior dielectric constants of 2.6, 1.1, 2.2 and 2.9 times, respectively.
The Von Neumann conditions for the upwind and Lax-Wendroff schemes of the Telegraph Equation
Authors: Ren Jiaojiao , Wu Cong 
Published: June 2023

Abstract
In this paper, the Von Neumann conditions for the Upwind and Lax-Wendroff schemes of the Telegraph Equation are derived, but then prove to be contradicted with the proportional relation between time and space steps, determined by voltage and current waves’ propagation velocity. The contradiction implies that the stable Upwind and Lax-Wendroff schemes of the Telegraph Equation are not physically applicable.
Foreground separation and constraints on primordial gravitational waves with the PICO space mission
Authors: Aurlien Ragnhild , Remazeilles Mathieu , Belkner Sebastian , Carron Julien , Delabrouille Jacques , Eriksen Hans Kristian , Flauger Raphael , Fuskeland Unni , Galloway Mathew , Górski Krzysztof M. , Hanany Shaul , Hensley Brandon S. , Colin Hill J. , Lawrence Charles R. , Pryke Clement , van Engelen Alexander , Wehus Ingunn Kathrine 
Published: June 2023

Abstract
PICO is a concept for a NASA probe-scale mission aiming to detect or constrain the tensor to scalar ratio r, a parameter that quantifies the amplitude of inflationary gravity waves.
We carry out map-based component separation on simulations with five foreground models and input r values r
in = 0 and r
in = 0.003. We forecast r determinations using a Gaussian likelihood assuming either no delensing or a residual lensing factor A
lens = 27%. By implementing the first full-sky, post component-separation, map-domain delensing, we show that PICO should be able to achieve A
lens = 22% – 24%. For four of the five foreground models we find that PICO would be able to set the constraints r < 1.3 × 10-4 to r < 2.7 × 10-4 (95%) if r
in = 0, the strongest constraints of any foreseeable instrument. For these models, r = 0.003 is recovered with confidence levels between 18σ and 27σ. We find weaker, and in some cases significantly biased, upper limits when removing few low or high frequency bands. The fifth model gives a 3σ detection when r
in = 0 and a 3σ bias with r
in = 0.003. However, by correlating r determinations from many small 2.5% sky areas with the mission's 555 GHz data we identify and mitigate the bias. This analysis underscores the importance of large sky coverage. We show that when only low multipoles ℓ ≤ 12 are used, the non-Gaussian shape of the true likelihood gives uncertainties that are on average 30% larger than a Gaussian approximation.
The CMB cold spot under the lens: ruling out a supervoid interpretation
Authors: Owusu Stephen , da Silveira Ferreira Pedro , Notari Alessio , Quartin Miguel 
Published: June 2023

Abstract
The Cosmic Microwave Background (CMB) anisotropies are thought to be statistically
isotropic and Gaussian. However, several anomalies are observed, including the CMB Cold Spot, an
unexpected cold ∼ 10° region with p-value ≲ 0.01 in standard
ΛCDM. One of the proposed origins of the Cold Spot is an unusually large void on the line
of sight, that would generate a cold region through the combination of integrated Sachs-Wolfe and
Rees-Sciama effects. In the past decade extensive searches were conducted in large scale
structure surveys, both in optical and infrared, in the same area for z ≲ 1 and did find
evidence of large voids, but of depth and size able to account for only a fraction of the
anomaly. Here we analyze the lensing signal in the Planck CMB data and rule out the hypothesis
that the Cold Spot could be due to a large void located anywhere between us and the surface of
last scattering. In particular, computing the evidence ratio we find that a model with a large
void is disfavored compared to ΛCDM, with odds 1 : 13 (1 : 20) for SMICA (NILC) maps,
compared to the original odds 56 : 1 (21 : 1) using temperature data alone.
Study of discharges in the CMS GEM GE1/1 station with LHC beam
Authors: Calzaferri S. 
Published: June 2023

Abstract
The Large Hadron Collider (LHC) and the experiments installed there are being upgraded for
the High Luminosity LHC project that will provide a greatly enlarged data sample in the search for
physics beyond the Standard Model. During Long Shutdown 2, from 2018 to the first months of 2022,
some of these upgrades were completed. In particular, the muon spectrometer of the CMS experiment
was upgraded with installation of the GE1/1 detector station, based on Gas Electron Multiplier
(GEM) technology. This station is positioned in the endcap region of the CMS muon system and
covers the pseudorapidity range 1.55 < |η| < 2.18. On the 5th of July, 2022, Run 3 of
the LHC began with collision energy of 13.6 TeV. The newly installed GEM detectors experienced
high-voltage discharges when the beams were colliding inside CMS. To monitor these events and to
understand how to safely operate the detectors, a study of these phenomena became necessary. The
intensity of discharge current and the discharge rate were recorded in different detectors as a
function of luminosity and time. It was observed that some chambers have a significantly higher
discharge rate than the modal value of rate over the entire chamber population. The reasons
responsible for this behavior are currently under investigation. In this contribution, an analysis
of discharges will be presented, illustrating the dependence of discharge rate on different LHC
beam configurations and the high voltage working point of the chambers.
Novel resistive charge-multipliers for dual-phase LAr-TPCs: towards stable operation at higher gains
Authors: Tesi A. , Moleri L. , Leardini S. , Breskin A. , Gonzalez-Diaz D. , Olano-Vegas L. , Jash A. , Bressler S. 
Published: June 2023

Abstract
Cryogenic versions of Resistive WELL (RWELL) and Resistive Plate WELL (RPWELL) detectors
have been developed, aimed at stable avalanche multiplication of ionization electrons in the vapor
phase of LAr (dual-phase TPC). In the RWELL, a thin resistive DLC layer deposited on top of an
insulator is inserted in between the electron multiplier (THGEM) and the readout anode; in the
RPWELL, a resistive ferrite plate is directly coupled to the THGEM. Radiation-induced ionization
electrons in the liquid are extracted into the gaseous phase. They drift into the THGEM's holes
where they undergo charge multiplication. Embedding resistive materials into the multiplier proved
to enhance operation stability due to the mitigation of electrical discharges — thus allowing
operation at higher charge gain compared to standard THGEM (a.k.a. LEM) multipliers. We present
the detector concepts and report on the main preliminary results.
Assessing nitrogen flow and nitrogen footprint in the food system of a subtropical island with a scenario to mitigate nitrogen load impacted by trade-dependent agriculture
Authors: Hamada Kosuke , Eguchi Sadao , Hirano Nanae , Asada Kei , Oka Naoko 
Published: June 2023

Abstract
Recent hikes in fertilizer, feed, and food prices threaten the food security of island-dwelling people who rely heavily on imports to sustain food supply and production. The influx of reactive nitrogen (Nr) through imports increases nitrogen load and degrades the environment. To overcome these problems, a robust and sustainable food system must be developed. In this study, we aimed to evaluate the present nitrogen flow in the food system of Ishigaki Island, located in the subtropical zone of Japan, and propose a measure to improve it based on the nitrogen footprint concept. Results showed that the major Nr-loss pathways for agricultural activity on the island were ‘crop-unused’ (37%) and ‘manure’ (43%). In food production, most of the Nr loss to the environment was related to export products, and less than 30% was related to island consumers. To meet the demand of food supply on the island, 5.1 times greater amount of food Nr than that of produced for island consumers was imported from overseas regions, placing the burden of Nr loss on such regions. We found that agricultural activities on the island mainly used chemical fertilizer; less than 13% of cattle manure was reused. To reduce the influx of Nr, we created a scenario in which 30% of chemical fertilizer was replaced by cattle manure. Results indicated 70% of the cattle manure produced on the island was necessary to achieve this scenario. This system could reduce Nr imports and Nr loss on the island by 16% and 17%, respectively. The proposed food system can be extended to other islands to overcome the recent price hikes and conserve the environment. This study is the first to present a detailed nitrogen flow in the food system of a tropical/subtropical island by using the nitrogen footprint concept.
Numerical modelling of reinforced concrete gravity retaining walls under seismic loads
Authors: Yamouni B El , Khannoussi F El , Khamlichi A 
Published: June 2023

Abstract
Due to their multiple uses and structural challenges they outline during normal circumstances and seismic events, retaining walls constitute an important concern for civil engineers. Design of these structures requires accurate determination of lateral earth pressure under various conditions. Considering the dynamical action under seismic excitation, the total lateral earth pressure for cohesion-less soil backfills is often estimated by using the Mononobe-Okabe method. Although this conventional method does not take into account the full characteristics of a seism, it has recovered a wide range of applications in practice. It is interesting therefore to compare its predictions to those of a more comprehensive analysis. In this study, a dynamic numerical modelling of reinforced concrete gravity retaining walls with cohesion-less backfill material was conducted using PLAXIS 2D software. Loma Prieta earthquake record was applied and different values of wall height and backfill soil stiffness were considered. Parametric studies were accomplished in order to assess the influence of key parameters on the vertical profile of dynamic active earth pressure and the resultant thrust. A good agreement between the numerically computed seismic lateral force acting on the wall was obtained in comparison with the conventional Mononobe-Okabe approach; however this last may yield oversizing.
Development of geometry variants and forming technology for metal diaphragms to increase the efficiency of diaphragm compressor
Authors: Solovev M , Leonhardt A , Graf A , Kunke A , Kräusel V 
Published: June 2023

Abstract
This article outlines the development of an elastically foldable, bistable diaphragm geometry that enables an increase in the compression volume of diaphragm compressors compared to the use of flat diaphragms. Using a Finite Element Model (FEM) in ABAQUS/Standard, several membrane geometries (truncated cone, cone, and dome) were calculated and analyzed with regard to their elastic deformation. Selected geometries were produced using Single Point Incremental Forming (SPIF) and tested by applying full-area pneumatic pressure to determine the diaphragm’s lifetime.
Effect of blank size on impact hydroforming of 2195 Al-Li alloy half-tube part with curvature
Authors: Zhu H L , Xu Y , Chen S F , Zhang S H 
Published: June 2023

Abstract
Aluminum-Lithium (Al-Li) alloy has excellent properties such as low density, high elastic modulus and high specific strength, and it is considered as the most ideal structural material in aerospace. However, due to the low plasticity of Al-Li alloy at room temperature, it is easy to crack during cold forming, so its application and development have been limited. In order to explore the possibility of improving the plasticity of 2195 Al-Li alloy at room temperature, a half-tube part with curvature and deep cavity structure was formed by using impact hydroforming (IHF) technology. In this paper, the process route of half-tube part was optimized and four sizes of blank were designed. Through finite element numerical simulation and analysis, it was found that the F area was prone to wrinkle defects when there was less material at the inner arc position, and the most serious thinning occurred in the design margin area. After analysis and comparison, the blank size with drawing ratio of 2.22 was finally selected. Based on the verification experiment, it was found that due to the material properties of Al-Li alloy and the characteristics of IHF, one-step forming was difficult, and the forming of half-tube part was prone to insufficient drawing depth or large area fracture; Although the part obtained by two-step forming also had cracks, the overall forming quality of the part would not be affected because they were located in the design margin area to be removed later. In addition, it was observed that the surface quality of the part removed the design margin area were free of wrinkles and cracks, which meets the objective design requirements.
Influence of elevated surface temperature on the formability in cold forming of aluminum alloy sheets
Authors: Hodžić E , Shafiee Sabet A , Silvayeh Z , Auer P , Drexler A , Sommitsch C , Domitner J 
Published: June 2023

Abstract
In recent decades, deep drawing has been widely used in the automotive industry for producing lightweight car body components of 5xxx and 6xxx aluminum alloys. Although sheets of these alloys are usually deep-drawn at room temperature, heat generated by friction and plastic deformation may locally increase the surface temperature of the drawing tools during the serial production of components. Therefore, this work investigates the influence of elevated surface temperatures of the tool on the formability of commercial hotmelt-lubricated 1.5 mm-thick EN AW-5182 and EN AW-6016-T4 sheets. Deep drawing experiments were performed at different constant surface temperatures between room temperature (RT) and 80 °C using a cross-shaped tool with open die. With increasing surface temperature, the maximum drawing depth – that was considered as indicator for the formability – decreased by about 21 % and 28 % for EN AW-6016-T4 and EN AW-5182, respectively. Tribological experiments performed using a pin-on-plate tribometer confirmed this trend. The results clearly showed that the coefficient of friction (COF) between the sheet and the tool significantly increase at elevated surface temperature; the most notable increase of the COF occurred between 40 °C and 60 °C.
Material variability effects on automotive part production process
Authors: Chezan A R , Atzema E H , Pilthammar J , Sigvant M 
Published: June 2023

Abstract
The current efforts to reduce the carbon footprint throughout the chain in the automotive industry by increased use of recycled materials poses new challenges for materials production and their use. The increase of steel scrap fraction in the current primary steel making processes, used for producing steel sheet metal for automotive components, possibly affects the material properties variability beyond the limits observed in the materials produced today despite mitigating actions in steel production. In this paper material variability increase was modelled by selecting deterministic values outside the range of the material grade used to design and manufacture an automotive part. The values were selected from an experimental data set representing the cold rolled mild steels material class range. The effects were studied numerically on a reverse engineered model of an existing automotive part production process. It was found that the manufacturing feasibility in this particular case is mainly affected by the weighted average plastic strain ratio and less by the degree of planar anisotropy.
Numerical modelling of shear cutting using particle methods
Authors: Sandin Olle , Prieto Juan Manuel Rodríguez , Hammarberg Samuel , Casellas Daniel 
Published: June 2023

Abstract
The use of Advanced High Strength Steel (AHSS) allows for lightweighting of sheet steel components, with maintained structural integrity of the part. However, AHSS grades show limitations in edge crack resistance, primarily influenced by sheared edge damage introduced by the shear cutting process. Numerical modelling of the shear cutting process can aid the understanding of the sheared edge damage, thus avoiding unforeseen edge cracking in the subsequent cold forming. However, the extreme deformations of the blank during the shear cutting process are likely to cause numerical instabilities and divergence using conventional Finite Element modelling. To overcome these challenges, this work presents the use of a particle-based numerical modelling method called the Particle Finite Element Method (PFEM). PFEM accurately solves some of the challenges encountered in shear cutting with the standard Finite Element method, such as large deformation, angular distortions, generation of new boundaries and presents an efficient way of transfer historical information from the old to the new mesh, minimising the results diffusion. The present work shows prediction of cut edge morphology of AHSS using a PFEM modelling scheme, where the numerical results are verified against experiments. With these results, the authors show new possibilities to obtain accurate numerical prediction of the shear cutting process, which promotes further advances in prediction of edge damaged related to shear cutting of AHSS.
Displacement driven simulation and material calibration based on digital image correlation Part I - Theory
Authors: Liebold C , Ilg C , Haufe A , Usta T , Sreenivasa V 
Published: June 2023

Abstract
Standard material characterization methods for subsequent finite element analysis rely on the simulation utilizing ideally discretized specimen that represent its geometrical characteristics as in the real experiment. Since many material models hold a set of parameters which is dependent on the discretization, e.g. the mesh size, especially when failure prediction for crash analysis is relevant, various mesh sizes are utilized during this calibration process. Optical measurement systems accompanying the experimental tests have become a standardized procedure, at least for a 2-dimensional (or specimen top-surface) measurements. Investigated calibration methods relying on the results of these optical measurements either include the derived strain field into the characterization process (full-field calibration), determine the crack path and iteratively derive plasticity curves (stepwise-modelling approach) or establish virtual fields based on the principal of virtual work allowing to solve for the scalar unknowns of the underlying chosen constitutive equation (virtual fields method). In the presented work, we directly use displacements measured using a GOM/ARAMIS system, mapped as boundary conditions for the nodal displacements of differently discretized specimen to establish a material characterization scheme being as close to the experiment as possible.
An overview of Methods for Simulating Sheet Metal Forming with Elastic Dies
Authors: Pilthammar J , Sigvant M , Islam M S , Schill M , Sjöblom S , Sjöblom V , Lind M 
Published: June 2023

AbstractSheet metal forming (SMF) simulations are traditionally carried out with rigid active forming surfaces. This means that the elasticity and dynamics of presses and die structures are ignored. The only geometries of the tools included in the simulations are the active forming surfaces. One reason for this simplification is the large amount of computational power that is required to solve finite element (FE) models that incorporates elastic stamping dies. Another reason is the lack of die CAD models before the later stages of stamping projects. Research during the last couple of decades indicated potential large benefits when including elastic dies in SMF simulations. For example, for simulating die try-out or for Digital Twins of presses and dies. Even though the need and potential benefits of elastic dies in simulations are well known it is not yet implemented on a wide scale. The main obstacles have been lacking data on presses and dies, long simulation times, and no standardized implementation in SMF software. This paper presents an overview of existing methods for SMF simulations with elastic dies and discuss their respective benefits and drawbacks. The survey of methods shows that simulation models with elastic tools will be needed for detailed analyses of forming operations and also for purposes like digital twins. On the other hand, simplified and robust models can be developed for non-FEA users to carry out simple one-step compensation of tool surfaces for virtual spotting purposes. The most promising and versatile method from the literature is selected, modified, and demonstrated for industrial sized dies.
Displacement based Simulation and Material Calibration based on Digital Image Correlation Part II - Application
Authors: Ilg C , Liebold C , Sreenivasa V , Haufe A , Karadogan C , Liewald M 
Published: June 2023

Abstract
An alternative approach to calibrate material models is proposed. The entire displacement field of a specimen measured with a DIC system was converted into boundary conditions by the Envyo® mapping software. These boundary conditions were imposed on all nodes in the corresponding LS-DYNA® simulation model. In this way a digital twin of the specimen geometry and the experimental kinematics was obtained. Considering the local stress equilibrium over the entire specimen and the equilibrium of global force integrated over many hypothetical cross sections, LS-OPT® was used to iteratively determine the isotropic model parameters of the tested material. A new tensile specimen geometry is introduced to get the most out of a single test. The findings suggest that, at present, convergence in iterative parameter optimization cannot be attained without prior filtering and smoothing of the DIC input data in time and space, despite the utilization of the chosen material model.