bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of semi-molten hollow particle spreading and deformation in plasma spraying
Authors: Zhang Mengjiao , Chen Lihua , Shan Lutong , Li Haoqun
Published: February 2024

Hollow yttrium-stabilized zirconia (YSZ) particles, which are often used to prepare high porosity coatings in industry, hit substrate at a fully molten state or semi-molten state due to the high temperature gradient of particles caused by the low thermal conductivity. Considering the hollow solid core large deformation and liquid solidification during the deposition of semi-molten hollow particles (SMHPs), a fluid-structure interaction model described by the coupled Eulerian and Lagrangian (CEL) method, is developed and validated to investigate the spreading results in thermal spraying. The empirical formula of dynamic viscosity based on the ABAQUS CEL method is proposed and verified for simulation of the liquid YSZ spreading and solidification. The compression ratio and plastic dissipation are calculated to reveal flattening and buckling phenomena of hollow solid core with different initial velocities and hollow radius. Moreover, a double-SMHP impact model is established to simulate the interaction of particle-particle-substrate, and the effect of flattening, buckling and structural self-contact on porosity is analyzed. Numerical simulation results show that hollow solid core large deformation induces instability accompanied by flattening, buckling or structural self-contact, which results in the reduction of layer porosity.
The physics case for neutrino–neutrino collisions
Authors: Qian Sitian , Yang Tianyi , Deng Sen , Xiao Jie , Gao Leyun , Levin Andrew Michael , Li Qiang , Lu Meng , You Zhengyun
Published: February 2024

Addressing the mass origin and properties of neutrinos is of strong interest to particle physics, baryogenesis and cosmology. Popular explanations involve physics beyond the standard model, for example, the dimension-5 Weinberg operator or heavy Majorana neutrinos arising from ‘seesaw’ models. The current best direct limits on the electron neutrino mass, derived from nuclei beta decay or neutrinoless double beta decay processes, are at the sub-electronvolt level. Here we propose a novel neutrino–neutrino collider where the neutrino beam is generated from TeV scale muon decays. Such collisions can happen between either neutrinos and anti-neutrinos, or neutrinos and neutrinos. We find that with a tiny integrated luminosity of about 10−5 fb−1 we can already expect to observe direct neutrino anti-neutrino annihilation,

ν

ν

¯

→
Z

, which also opens the door to explore neutrino related resonances

ν

ν

¯

→
X

. The low luminosity requirement can accommodate a relatively large emittance muon beam. Such a device would also allow for probing heavy Majorana neutrino and effective Majorana neutrino mass through ν
ν → HH to a competitive level, for both electron and muon types.
A generalized time-domain constitutive finite element approach for viscoelastic materials
Authors: Abercrombie Eric , Gregory McDaniel J , Walsh Timothy
Published: February 2024

Despite the existence of time domain finite element formulations for viscoelastic materials, there are still substantial ways to improve the analysis. To the authors’ knowledge, the formulation of the problem is always done with respect to a single constitutive relation and so limits the implementer to a single scheme with which to model relaxation. Furthermore, all current constitutive relations involve the finding of fitting parameters for an analytical function, which is a sufficiently painful process to warrant the study of best fitting procedures to this day. In contrast, this effort is the first full derivation of the two dimensional problem from fundamental principles. It is also the first generalization of the problem, which frees users to select constitutive relations without re-derivation or re-expression of the problem. This approach is also the first approach to the problem that could lead to the elimination of constitutive relations for representing relaxation in viscoelastic materials. Following, the full derivation, several common constitutive relations are outlined with analysis of how they may best be implemented in the generalized form. Several expressions for viscoelastic terms are also provided given linear, quadratic, and exponential interpolation assumptions.
Collapse dynamics for two-dimensional space-time nonlocal nonlinear Schrödinger equations
Authors: Cole Justin T , Aurko Abdullah M , Musslimani Ziad H
Published: February 2024

The question of collapse (blow-up) in finite time is investigated for the two-dimensional (non-integrable) space-time nonlocal nonlinear Schrödinger equations. Starting from the two-dimensional extension of the well known AKNS

q
,
r

system, three different cases are considered: (i) partial and full parity-time (PT) symmetric, (ii) reverse-time (RT) symmetric, and (iii) general

q
,
r

system. Through extensive numerical experiments, it is shown that collapse of Gaussian initial conditions depends on the value of its quasi-power. The collapse dynamics (or lack thereof) strongly depends on whether the nonlocality is in space or time. A so-called quasi-variance identity is derived and its relationship to blow-up is discussed. Numerical simulations reveal that this quantity reaching zero in finite time does not (in general) guarantee collapse. An alternative approach to the study of wave collapse is presented via the study of transverse instability of line soliton solutions. In particular, the linear stability problem for perturbed solitons is formulated for the nonlocal RT and PT symmetric nonlinear Schrödinger (NLS) equations. Through a combination of numerical and analytical approaches, the stability spectrum for some stationary one soliton solutions is found. Direct numerical simulations agree with the linear stability analysis which predicts filamentation and subsequent blow-up.
Measurement of the 12C(p,n)12N reaction cross section below 150 MeV
Authors: Zapien-Campos Brian , Ahmadi Ganjeh Zahra , Both Stefan , Dendooven Peter
Published: February 2024

Objective. Proton therapy currently faces challenges from clinical complications on organs-at-risk due to range uncertainties. To address this issue, positron emission tomography (PET) of the proton-induced 11C and 15O activity has been used to provide feedback on the proton range. However, this approach is not instantaneous due to the relatively long half-lives of these nuclides. An alternative nuclide, 12N (half-life 11 ms), shows promise for real-time in vivo proton range verification. Development of 12N imaging requires better knowledge of its production reaction cross section. Approach. The 12C(p,n)12N reaction cross section was measured by detecting positron activity of graphite targets irradiated with 66.5, 120, and 150 MeV protons. A pulsed beam delivery with 0.7–2 × 108 protons per pulse was used. The positron activity was measured during the beam-off periods using a dual-head Siemens Biograph mCT PET scanner. The 12N production was determined from activity time histograms. Main results. The cross section was calculated for 11 energies, ranging from 23.5 to 147 MeV, using information on the experimental setup and beam delivery. Through a comprehensive uncertainty propagation analysis, a statistical uncertainty of 2.6%–5.8% and a systematic uncertainty of 3.3%–4.6% were achieved. Additionally, a comparison between measured and simulated scanner sensitivity showed a scaling factor of 1.25 (±3%). Despite this, there was an improvement in the precision of the cross section measurement compared to values reported by the only previous study. Significance. Short-lived 12N imaging is promising for real-time in vivo verification of the proton range to reduce clinical complications in proton therapy. The verification procedure requires experimental knowledge of the 12N production cross section for proton energies of clinical importance, to be incorporated in a Monte Carlo framework for 12N imaging prediction. This study is the first to achieve a precise measurement of the 12C(p,n)12N nuclear cross section for such proton energies.
Observation of the low electron density and electron temperature in an unmagnetized cascaded arc helium plasma by laser Thomson scattering approach
Authors: Wang Yong , Zhou Lina , Shi Jielin , Li Yu , Li Cong , Feng Chunlei , Ding Hongbin
Published: February 2024

In this study, the electron density (ne
) and temperature (Te
) in an unmagnetized cascaded arc helium (He) plasma are precisely determined using cutting-edge laser Thomson scattering. In our experimental scope, ne
is only 1018 m−3 and Te
is less than 0.2 eV, both of which are substantially lower than in linear plasma devices (LPDs). The comparison of ne
and Te
values in He plasma with those in cascaded arc Ar plasma reveals that these two parameters are likewise significantly lower in He plasma than they are in Ar plasma on average. In comparison to Ar gas, the degree of ionization of He is low due to its high ionization potential, and diffusive loss dominates due to its light weight, both of which result in a lower ne
. Meanwhile, these two characteristics render the three-body recombination interaction between electrons and He+ ions in He plasma insignificant, thus the electrons cannot be heated effectively, explaining why Te
is lower. This study will provide foundational data and build the groundwork for a thorough knowledge of cascaded arc He plasma in LPDs and plasma windows.
When physics meets chemistry at the dynamic glass transition
Authors: Lu Haibao
Published: February 2024

Can the laws of physics be unified? One of the most puzzling challenges is to reconcile physics and chemistry, where molecular physics meets condensed-matter physics, resulting from the dynamic fluctuation and scaling effect of glassy matter at the glass transition temperature. The pioneer of condensed-matter physics, Nobel Prize-winning physicist Philip Warren Anderson referred to this gap as the deepest and most interesting unsolved problem in condensed-matter physics in 1995. In 2005, Science, in its 125th anniversary publication, highlighted that the question of ‘what is the nature of glassy state?’ was one of the greatest scientific conundrums for the next quarter century. However, the nature of the glassy state and its connection to the glass transition have not been fully understood owing to the interdisciplinary complexity of physics and chemistry, governed by physical laws at the condensed-matter and molecular scales, respectively. Therefore, the study of glass transition is essential to explore the working principles of the scaling effects and dynamic fluctuations in glassy matter and to further reconcile the interdisciplinary complexity of physics and chemistry. Initially, this paper proposes a thermodynamic order-to-disorder free-energy equation for microphase separation to formulate the dynamic equilibria and fluctuations, which originate from the interplay of the phase and microphase separations during glass transition. Then, the Adam–Gibbs domain model is employed to explore the cooperative dynamics and molecular entanglement in glassy matter. It relies on the concept of transition probability in pairing, where each domain contains e + 1 segments, in which approximately 3.718 segments cooperatively relax in a domain at the glass transition temperature. This model enables the theoretical modeling and validation of a previously unverified statement, suggesting that 50–100 individual monomers would relax synchronously at glass transition temperature. Finally, the constant free-volume fraction of 2.48% is phenomenologically obtained to achieve a condensed constant (C) of C= 0.12(1−γ) = 1.501 × 10−11 J·mol−1·K−1, where γ represents the superposition factor of free volume and is characterised using the cumulative Poisson distribution function, at the condensed-matter scale, analogous to the Boltzmann constant (k
B) and gas constant (R).
Recent progress and future outlook of digital twins in structural health monitoring of civil infrastructure
Authors: Sakr Micheal , Sadhu Ayan
Published: February 2024

Abstract

Digital twins (DTs) have witnessed a paramount increase in applications in multidisciplinary engineering systems. With advancements in structural health monitoring (SHM) methods and implementations, DT-based maintenance and operation stages have been implemented significantly during the life cycle of civil infrastructure. Recent literature has started laying the building blocks for incorporating the concept of DTs with SHM of large-scale civil infrastructure. This paper undertakes a systematic literature review of studies on DT-related applications for SHM of civil structures. It classifies the articles based on thematic case studies: transportation infrastructure (i.e. bridges, tunnels, roads, and pavements), buildings, off-shore marine infrastructure and wind turbines, and other civil engineering systems. The proposed review is further uniquely sub-classified using diverse modeling approaches such as building information modeling, finite element modeling, 3D representation, and surrogate and hybrid modeling used in DT implementations. This paper is solely focused on applications relating DTs to SHM practices for various civil engineering infrastructures, hence highlighting its novelty over previous reviews. Gaps and limitations emerging from the systematic review are presented, followed by articulating future research directions and key conclusions.
Replication and study of anomalies in LK-99—the alleged ambient-pressure, room-temperature superconductor
Authors: Habamahoro T , Bontke T , Chirom M , Wu Z , Bao J M , Deng L Z , Chu C W
Published: February 2024

We have studied LK-99 [Pb10−x
Cu
x
(PO4)6O], alleged by Lee et al to exhibit superconductivity above room temperature and at ambient pressure, and have reproduced all anomalies in electric and magnetic measurements that they reported as evidence for the claim of LK-99 being an ambient-pressure, room-temperature superconductor. We found that these anomalies are associated with the structural transition of the Cu2S impurity in their sample and not with superconductivity.
The sensitivity demonstration and propagation of hyper-geometric soliton waves in plasma physics of Kairat-II equation
Authors: Faridi Waqas Ali , Tipu Ghulam Hussain , Myrzakulova Zhaidary , Myrzakulov Ratbay , AlQahtani Salman A , Pathak Pranavkumar
Published: February 2024

This study investigates the Kairat-II equation, describing optical pulse behavior in optical fibers and plasma. To uncover new solitary wave profiles, the study employs an extended direct algebraic method. This kind of solution has never been reached in research prior to this study. This innovative approach efficiently encompasses a comprehensive set of thirty-seven solitonic wave profiles, spanning various soliton families. The investigation unveils novel solitonic wave patterns, including plane solutions, hyper-geometric solutions, mixed hyperbolic solutions, periodic and mixed periodic solutions, mixed trigonometric solutions, trigonometric solutions, shock solutions, mixed shock singular solutions, mixed singular solutions, complex solitary shock solutions, singular solutions, and shock wave solutions. To demonstrate the pulse propagation characteristics, the research presents 2-D, 3-D, and contour graphics based on parameter values, aiding in a better understanding of the phenomenon.
Electronic and transport properties of boron and nitrogen passivated zigzag graphene nanoribbons
Authors: Narwaria Premlata , Chauhan Satyendra Singh , Shrivastava A K
Published: February 2024

A systematic study is conducted on 8ZGNR by edge terminations with boron and nitrogen at I and II termination sites by replacing hydrogen atoms in a single layer and in two probe systems. Electronic properties were observed in the DFT framework. Non-equilibrium green’s function (NEGF) tool was used to study the transport properties. Analysis of band structure, total energy, formation energy, and projected density of states (PDOS) suggest that despite Boron and Nitrogen passivation at all the termination sites, the electronic behavior of the system remains metallic. The analysis of Transmission spectra also confirms its metallic behavior in all these cases. This study reveals that B and N passivated graphene nanoribbons are sensitive to electronic transmission. This fact makes it potentially useful for application in sensors, memory devices and many other nano-electronic devices.
Spatially uncorrelated two port MIMO DRA using phase gradient PRS for dual directional pattern diversity
Authors: Yadav Abhay Krishna , Verma Sudhanshu , Das Gourab , Sharma Anand , Tiwari Arvind Kumar
Published: February 2024

This study presents a system utilizing a cylindrical shape ceramic along with a suspended frequency selective surface (FSS), designed for multiple input multiple output (MIMO) applications with dual ports. The proposed antenna system showcases dual pattern diversity properties introducing spatially uncorrelated pattern. Key features of the structured radiator include the arrangement of cylindrical ceramic and the incorporation of an FSS. The alumina ceramic is purposefully placed on the upper part of the dielectric with a joint ground plane. These ceramics are stimulated using circular aperture. To reduce the far-field correlation, FSS with similar phase gradients are placed at the top of DRA at a certain distance. This arrangement yields two distinct radiation patterns from the two ports, ensuring a diverse radiation pattern for the antenna. The proposed technique yields significant improvements, surpassing 10 dB in isolation and achieving a 70% improvement in correlation values. The measured results validate the applicability of this antenna structure for WLAN access point applications within the 5.15–5.35 GHz frequency range.
Electro-microgellation of CS/PL spheres in situ self-embedded with AgNPs as a losartan delivery system
Authors: Zidan Mostafa M , Reicha Fikry Mohamed , Mansour-Gabr Mohamed M , Elmezayyen Ayman S
Published: February 2024

In situelectrosynthesis of new hybrid colloidal microgel particles of chitosan (CS)-pullulan (PL) self-embedded with AgNPs and introduced as a drug carrier for losartan (LOS) as a drug model. The impact of using Platinum (Pt) and Silver (Ag) sheets as anode and the electrosynthesis time on the formation mechanism, morphology, compositional and structural properties have been examined. The prepared samples characterized using uv–visible spectroscopy (UV–vis), transmission electron microscope (TEM), zeta potential, Fourier transform infrared spectroscopy (FTIR), Inductively coupled plasma optical emission spectroscopy (ICP-OES), x-ray diffraction analysis (XRD), and stability test. In addition to the Assessment of the antibacterial activity of the prepared samples. Also, incorporation of LOSin situduring the preparation of the microgel was investigated. The results demonstrated that uniform AgNPs with an average size 5.4 nm successfullyin situself-embedded within CS/PL microgel particles of a dual size distribution 151.4 and 43.5 nm with surface charge +25 mV. Besides, the incorporation of AgNPs during the electrosynthesis process played a crucial role in the morphology transition from pearl-necklace to microsphere. additionally, stability examination of the microgel particles introduced a valuable result that the single sphere containing Ag+ions underwent a slow reduction rate in consistency with nucleation favored overgrowth. Incorporation of AgNPs within CS/PL microgel has considerably enhanced the antimicrobial potential of the realized CS/PL against both gram-positive and gram-negative bacteria Investigation of the ability of the losartan incorporation explored a stable core/shell like structure with average size 95 nm and zeta potential + 39 mV promoting the spheres stability.
Utilizing a third order difference scheme in numerical method of lines for solving the heat equation
Authors: Yaseen Muhammad , Batool Sania
Published: February 2024

Obtaining the numerical solution for partial differential equations (PDEs) is a fundamental task in computational mathematics and scientific computing. In this work, we propose a third order numerical method of lines (MOL) based on difference schemes for the efficient and accurate approximation of heat equation. The method combines the flexibility of MOL with the superior accuracy of higher order difference schemes. The proposed approach begins by discretizing the spatial domain, and then applies higher order difference schemes to approximate the spatial derivatives in the PDE. The MOL framework is utilized to transform the resultant set of ordinary differential equations to a system of algebraic equations, facilitating their solution through an appropriate numerical method of choice. We have utilized the Adams method for this purpose. We analyze the stability of the proposed method and establish conditions under which it yields accurate and reliable solutions. We present the theoretical foundations of the method and discuss its implementation. We also present numerical results that demonstrate the procedure’s precision and effectiveness. The results show that the method is able to achieve high accuracy with relatively few grid points, and the results are compared with those obtained by some existing numerical schemes accessible in the literature.
Simulating quantum backflow on a quantum computer
Authors: Goussev Arseni , Joo Jaewoo
Published: February 2024

Quantum backflow is a counterintuitive effect in which the probability density of a free particle moves in the direction opposite to the particle’s momentum. If the particle is electrically charged, then the effect can be viewed as the contrast between the direction of electric current and that of the momentum. To date, there has been no direct experimental observation of quantum backflow. However, the effect has been simulated numerically (using classical computers) and optically (using classical light). In this study, we present the first simulation of quantum backflow using a real quantum computer.
Spectators no more! How even unimportant fields can ruin your Primordial Black Hole model
Authors: Wilkins A. , Cable A.
Published: February 2024

In this work we terminate inflation during a phase of Constant Roll by means of a waterfall field coupled to the inflaton and a spectator field. The presence of a spectator field means that inflation does not end at a single point, ϕ
e, but instead has some uncertainty resulting in a stochastic end of inflation. We find that even modestly coupled spectator fields can drastically increase the abundance of Primordial Black Holes (PBHs) formed by many orders of magnitude. The power spectrum created by the inflaton can be as little as 10-4 during a phase of Ultra Slow-Roll and still form a cosmologically relevant number of PBHs. We conclude that the presence of spectator fields, which very generically will alter the end of inflation, is an effect that cannot be ignored in realistic models of PBH formation.
Spectrum of gravitational waves from long-lasting primordial sources
Authors: Ramazanov Sabir
Published: February 2024

We discuss long-lasting gravitational wave sources arising and operating during
radiation-dominated stage. Under a set of assumptions, we establish the correspondence between
cosmological evolution of a source and the resulting gravitational wave spectrum. Namely, for the
source energy density ρs
falling as a power law characterized by the exponent β, i.e., ρs
 ∝ 1/aβ
, where a is the Universe scale factor, the spectrum takes the form Ωgw ∝ f
2β-8 in certain ranges of values of constant β and frequencies f. In particular, matching to the best fit power law shape of stochastic gravitational wave
background discovered recently by Pulsar Timing Array collaborations, one identifies β ≈ 5. We demonstrate the correspondence with concrete examples of long-lasting sources:
domain walls and cosmic strings.
OSIRIS-REx constraints on local dark matter and cosmic neutrino profiles
Authors: Tsai Yu-Dai , Eby Joshua , Arakawa Jason , Farnocchia Davide , Safronova Marianna S.
Published: February 2024

We derive purely gravitational constraints on dark matter and cosmic neutrino profiles in
the solar system using asteroid (101955) Bennu. We focus on Bennu because of its extensive
tracking data and high-fidelity trajectory modeling resulting from the OSIRIS-REx mission. We find
that the local density of dark matter is bound by ρ
DM ≲ 3.3 × 10-15 kg/m3 ≃ 6 × 106 ρ̅DM, in the vicinity of ∼ 1.1 au (where ρ̅DM ≃ 0.3 GeV/cm3). We show that high-precision tracking data of solar
system objects can constrain cosmic neutrino overdensities relative to the Standard Model
prediction n̅ν, at the level of η ≡ n
ν/n̅ν ≲ 1.7 × 1011(0.1 eV/mν
) (Saturn), comparable to the existing bounds from KATRIN and other
previous laboratory experiments (with mν
the neutrino mass). These local bounds have
interesting implications for existing and future direct-detection experiments. Our constraints
apply to all dark matter candidates but are particularly meaningful for scenarios including solar
halos, stellar basins, and axion miniclusters, which predict overdensities in the solar
system. Furthermore, introducing a DM-SM long-range fifth force with a strength α̃D
times stronger than gravity, Bennu can set a constraint on ρ
DM ≲ ρ̅DM(6 × 106/α̃D). These constraints can be improved in the future
as the accuracy of tracking data improves, observational arcs increase, and more missions
visit asteroids.
A new analytical model of magnetofluids surrounding rotating black holes
Authors: Hou Yehui , Zhang Zhenyu , Guo Minyong , Chen Bin
Published: February 2024

In this study, we develop a simplified magnetofluid model in the framework of GRMHD. We consider an ideal, adiabatic fluid composed of two components, ions and electrons, having a constant ratio between their temperatures. The flows are assumed to be governed by gravity, enabling us to employ the ballistic approximation, treating the streamlines as timelike geodesics. We show that the model is analytically solvable around a rotating black hole if the angular velocity of the geodesicuθis vanishing. In the corresponding solution, which is named the conical solution, we derive a comprehensive set of explicit expressions for the thermodynamics and the associated magnetic field. Furthermore, we explore the potential applications of our model to describe the thick disks and the jets at the horizon scale. Our model provides a direct pathway for the study of black hole imaging.
Improving constraints on primordial non-Gaussianity using neural network based reconstruction
Authors: Flöss Thomas , Daniel Meerburg P.
Published: February 2024

We study the use of U-Nets in reconstructing the linear dark matter density field and its
consequences for constraining cosmological parameters, in particular primordial
non-Gaussianity. Our network is able to reconstruct the initial conditions of redshift z = 0
density fields from N-body simulations with 90% accuracy out to k ≤ 0.4 h/Mpc, competitive
with state-of-the-art reconstruction algorithms at a fraction of the computational cost. We study
the information content of the reconstructed z = 0 density field with a Fisher analysis using the QUIJOTE simulation suite, including non-Gaussian initial conditions. Combining the pre-
and post-reconstructed power spectrum and bispectrum data up to k
max = 0.52 h/Mpc, we
find significant improvements in all parameters. Most notably, we find a factor 3.65 (local),
3.54 (equilateral), and 2.90 (orthogonal) improvement on the marginalized errors of f
NL as compared to only using the pre-reconstructed data. We show that these improvements can
be attributed to a combination of reduced data covariance and parameter degeneracy. The results
constitute an important step towards a more optimal inference of primordial non-Gaussianity from
non-linear scales.
Pion-photon and kaon-photon transition distribution amplitudes in the Nambu–Jona-Lasinio model*
Authors: Zhang 张 Jin-Li 金利 , Wu 吴 Jun 军
Published: February 2024

The Nambu–Jona-Lasinio model is utilized to investigate the pion- and kaon-photon leading-twist transition distribution amplitudes using proper time regularization. Separately, the properties of the vector and axial vector pion-photon transition distribution amplitudes are examined, and the results meet the desired properties. Our study involves sum rule and polynomiality condition. The vector and axial vector pion-photon transition form factors that are present in the

process are the first Mellin moments of the pion-photon transition distribution amplitudes. The vector transition form factor originates from the internal structure of hadrons, the axial current can be coupled to a pion, this pion is virtual, and its contribution will be present independently of the external hadrons. The kaon transition form factors are similar. The vector form factor's value at zero momentum transfer is determined by the axial anomaly, while this is not the case for the axial one. The vector and axial form factors, as well as the neutral pion vector form factor

, are depicted. According to our findings, the pion axial transition form factor is harder than the vector transition form factor and harder than the electromagnetic form factor. We also discuss the link between

and

transitions distribution amplitudes.
Different coalescence sources of light nucleus production in Au-Au collisions at
GeV*
Authors: Wang 王 Rui-Qin 瑞芹 , Lv 吕 Ji-Peng 济鹏 , Li 李 Yan-Hao 彦豪 , Song 宋 Jun 军 , Shao 邵 Feng-Lan 凤兰
Published: February 2024

We study the production of light nuclei in the coalescence mechanism of Au-Au collisions at midrapidity at

GeV. We derive analytic formulas of the momentum distributions of two bodies, three bodies, and four nucleons coalescing into light nuclei and naturally explain the transverse momentum spectra of the deuteron (d), triton (t), helium-3 (3He), and helium-4 (4He). We reproduce data on the yield rapidity densities, yield ratios, and averaged transverse momenta of d, t, 3He, and 4He and provide the proportions of contributions from different coalescence sources for t, 3He, and 4He in their production. We find that besides nucleon coalescence, nucleon+nucleus coalescence and nucleus+nucleus coalescence may play requisite roles in light nucleus production in Au-Au collisions at

GeV.
Micro-particle injection experiments in ADITYA-U tokamak using an inductively driven pellet injector
Authors: Pahari Sambaran , P.P. Rahulnath , Savita Aditya Nandan , Maurya Pradeep Kumar , Jha Saroj Kumar , Shiv Neeraj , K. Raghavendra , Hemani Harsh , Nagaraju Belli , Mahar Sukantam , Rao Manmadha , Suryaprasad I.V.V. , Malshe U.D. , Ghosh J. , Doshi B.R. , Chattopadhyay Prabal Kumar , Tanna R.L. , Jadeja K.A. , Patel K.M. , Kumar Rohit , Macwan Tanmay , Raj Harshita , Aich S. , Singh Kaushlender , Dolui Suman , Kumawat D. , Makwana M.N. , Shah K.S. , Gupta Shivam , Balakrishnan V. , Gupta C.N. , Patnaik Swadesh Kumar , Edappala Praveenlal , Shah Minsha , Kadia Bhavesh , Yadava Nandini , Shah Kajal , Shukla G. , Chowdhuri M.B. , Manchanda R. , Ramaiya Nilam , Kumar Manoj , Nagora Umesh , S. Varsha , Pathak S.K. , Asudani Kumudni , Chaudhuri Paritosh , Maya P.N. , Goswami Rajiv , Sen A. , Saxena Y.C. , Pal R. , Chaturvedi S.
Published: February 2024

A first-of-its-kind, inductively driven micro-particle (Pellet) accelerator and injector have been developed and operated successfully in ADITYA-U circular plasma operations, which may ably address the critical need for a suitable disruption control mechanism in ITER and future tokamak. The device combines the principles of electromagnetic induction, pulse power technology, impact, and fracture dynamics. It is designed to operate in a variety of environments, including atmospheric pressure and ultra-high vacuum. It can also accommodate a wide range of pellet quantities, sizes, and materials and can adjust the pellets’ velocities over a coarse and fine range. The device has a modular design such that the maximum velocity can be increased by increasing the number of modules. A cluster of lithium titanate/carbonate (Li2TiO3/Li2CO3) impurity particles with variable particle sizes, weighing ∼50–200 mg are injected with velocities of the order of ∼200 m s−1 during the current plateau in ADITYA-U tokamak. This leads to a complete collapse of the plasma current within ∼5–6 ms of triggering the injector. The current quench time is dependent on the amount of impurity injected as well as the compound, with Li2TiO3 injection causing a faster current quench than Li2CO3 injection, as more power is radiated in the case of Li2TiO3. The increase in radiation due to the macro-particle injection starts in the plasma core, while the soft x-ray emission indicates that the entire plasma core collapses at once.
Influence of working height on the energy consumption of an industrial robot
Authors: Bočák R , Holubek R , Kusá M
Published: February 2024

Electricity consumption is a big problem not only for the economy, but also for the environment. More and more electricity is used, so it is necessary to find a way to save it. This article focuses on the electrical energy consumption of an industrial robot by changing its working height. The goal is to find out at which height it is most suitable to work in order to achieve the lowest possible energy consumption. Research is realized on industrial robot ABB IRB 6700 using simulation tools such as ABB RobotStudio and Process Simulate, where different trajectory heights are simulated. The trajectories are dimensioned according to the size of the robot. Also, the trajectories are designed to maximize the use of the robot’s axis. This method makes it possible to reduce energy consumption even before the robot is physically located in the factory and its position cannot be changed.
Influence of Motion Mechanism Change in 3D Printers on the Quality of Printed Models
Authors: Csekei M , Šido J , Ružarosvský R , Michal D , Milde J
Published: February 2024

The objective of this study is to compare the quality of 3D printed models manufactured using the Fused Filament Fabrication (FFF) method. The samples were fabricated using a robotic arm with 4 axes and conventional 3D printers. The focus of this experiment lies in assessing the influence of the devices’ structural design on the resulting quality of the 3D printed models. Additionally, the study aims to identify the strengths and limitations of each device and define their respective applicability. The 3D model designed for this investigation comprises intricate geometrical shapes specifically chosen to evaluate the precision and repeatability of layer deposition while establishing geometric tolerances and determining shape deviations. The samples were 3D printed under identical printing conditions and parameters, and subsequently, these produced samples will undergo 3D digitization through an optical scanner, namely ATOS II Triple Scan. The obtained data will then be subjected to a comparative analysis utilizing GOM Inspect software to determine the geometric tolerances. The findings from this analysis will be critically evaluated and serve as a basis for informing and guiding future research endeavors.
Researches regarding power quality at the hot rolling mills’ power supply
Authors: Ivascanu P , Militaru G , Panoiu M , Panoiu C
Published: February 2024

The study described in the paper was carried out through measurements taken at a feed station in a hot rolling line. The aforementioned measures are appropriate for the purpose of analyzing power quality. The measurements were taken using a three-phase power quality analyzer. Measurements were taken for voltage and current values, as well as for active, reactive, and apparent powers. The analysis of the measurements taken indicates that the power quality is affected by the nonlinearity of the load. As a consequence, the level of reactive power becomes higher, leading to a reduced power factor.
RES growth linked to grid development. Case Study: Romania
Authors: Chioncel P C , Anghel-Drugărin C V , Tirian G O
Published: February 2024

The paper presents Romania to illustrate how more production capacities from renewable energy sources can be integrated as part of the environmental protection and geostrategic policies, in an accelerated energy transition process. Increasing electricity production, especially for the widespread development of wind turbines and rooftop solar PV systems, requires the development of the electrical grid and increased interconnection capacity. The authors of this report also take into account the behavior in different seasons, cold and warm, in terms of the amount of renewable energy injected into the network. The data used in the study is based on the interpreting and associations of various information at the national and European levels, highlighting that the benefits of renewable energy are not only seen in terms of significant reductions in environmental impact but also in terms of cheaper energy! In summary, it is assumed that in 2023-2026, the electricity demand at the level of quality indicators will be covered by investments in new generation facilities related to grid reinforcement measures.
Research regarding oxygen content reduction in steels
Authors: Poenaru I O , Ardelean E , Berghian A Budiul , Magaon M , Trisovic Z
Published: February 2024

Actual paperwork reflects obtained results of technological analyse of reducing oxygen content in steel for pipe manufacturing, enterprised in a steel furnance equipped with a triple aggregate EAF-LF-VD. Oxygen content was measured during manufacturing process in Loading Furnance and Vacuum Degasing and has been analysed in comparison with several parameters. The results are presented using Matlab through regression surfaces and correlation equations and highlights the influence of analysed factors on oxygen content variation in steel.
The variation of the hardness of high-strength steels depending on the microstructures specific of tempering
Authors: Mihuț G , Ardelean M , Popa E
Published: February 2024

The properties of steel depend on its chemical composition and structure. The modification of the structure in order to change the properties in a certain way is not only the main purpose of heat treatment, but also the only purpose, because the heat treatment regime influences the variation of properties through the variation of the steel structure.

It is only by correlating the variation in structure with hardness that we can answer how heat treatment influences hardness, which also depends on the stress state.

The tempering results are mainly influenced by the heating temperature, holding time and less sensitively by the tempering cooling rate (air, oil) as shown in the research carried out and presented in this paper.

Tempering reduces hardness, internal stresses, the amount of residual austenite and increases elongation, necking and resilience at the expense of strength.

The characteristics of tempering structures are clearly superior to equilibrium (annealing) structures in that the degree of dispersion of the structure is greater and the shape of the carbides and constituents is fine globular.
Positive maps from the walled Brauer algebra
Authors: Balanzó-Juandó Maria , Studziński Michał , Huber Felix
Published: February 2024

We present positive maps and matrix inequalities for variables from the positive cone. These inequalities contain partial transpose and reshuffling operations, and can be understood as positive multilinear maps that are in one-to-one correspondence with elements from the walled Brauer algebra. Using our formalism, these maps can be obtained in a systematic and clear way by manipulating partially transposed permutation operators under a partial trace. Additionally, these maps are reasonably easy in construction by combining an algorithmic approach with graphical calculus.
Verifiable quantum protocol for dynamic secure multiparty summation based on homomorphic encryption
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Authors: Luo Mei , Li Fulin , Liu Li , Zhu Shixin
Published: February 2024

The research of quantum secure multiparty computation is a subject of great importance in modern cryptography. In this study, we construct a verifiable quantum protocol for dynamic secure multiparty summation based on the cyclic property of d-level MUBs. Our protocol can realize dynamic parameter update in the aspect of members and secret inputs, improving the practicality of the protocol. Moreover, a verification mechanism for result checking by applying ElGamal homomorphic encryption is given, and further enables the detectability of cheating behaviors, making our protocol safer. The security analysis proves the proposed protocol not only can resist a range of typical attacks from outside and inside, but also is secure against dishonest revoked participant attack which has been neglected in previous dynamic quantum summation protocols. From a theoretical perspective, compared with existing summation protocols, the protocol provides better practicability, higher privacy protection, and higher efficiency.
Automated detection of vertebral body misalignments in orthogonal kV and MV guided radiotherapy: application to a comprehensive retrospective dataset
Authors: Charters John A , Luximon Dishane , Petragallo Rachel , Neylon Jack , Low Daniel A , Lamb James M
Published: February 2024

Objective. In image-guided radiotherapy (IGRT), off-by-one vertebral body misalignments are rare but potentially catastrophic. In this study, a novel detection method for such misalignments in IGRT was investigated using densely-connected convolutional networks (DenseNets) for applications towards real-time error prevention and retrospective error auditing. Approach. A total of 4213 images acquired from 527 radiotherapy patients aligned with planar kV or MV radiographs were used to develop and test error-detection software modules. Digitally reconstructed radiographs (DRRs) and setup images were retrieved and co-registered according to the clinically applied alignment contained in the DICOM REG files. A semi-automated algorithm was developed to simulate patient positioning errors on the anterior-posterior (AP) and lateral (LAT) images shifted by one vertebral body. A DenseNet architecture was designed to classify either AP images individually or AP and LAT image pairs. Receiver-operator characteristic curves (ROC) and areas under the curves (AUC) were computed to evaluate the classifiers on test subsets. Subsequently, the algorithm was applied to the entire dataset in order to retrospectively determine the absolute off-by-one vertebral body error rate for planar radiograph guided RT at our institution from 2011–2021. Main results. The AUCs for the kV models were 0.98 for unpaired AP and 0.99 for paired AP-LAT. The AUC for the MV AP model was 0.92. For a specificity of 95%, the paired kV model achieved a sensitivity of 99%. Application of the model to the entire dataset yielded a per-fraction off-by-one vertebral body error rate of 0.044% [0.0022%, 0.21%] for paired kV IGRT including one previously unreported error. Significance. Our error detection algorithm was successful in classifying vertebral body positioning errors with sufficient accuracy for retrospective quality control and real-time error prevention. The reported positioning error rate for planar radiograph IGRT is unique in being determined independently of an error reporting system.
Application of Jacobi stability analysis to a first-order dynamical system: relation between nonlinearizability of one-dimensional differential equation and Jacobi stable region
Authors: Hirakui Yuma , Yajima Takahiro
Published: February 2024

In this study, we discuss Jacobi stability in equilibrium and nonequilibrium regions for a first-order one-dimensional system using deviation curvatures. The deviation curvature is calculated using the Kosambi-Cartan-Chern theory, which is applied to second-order differential equations. The deviation curvatures of the first-order one-dimensional differential equations are calculated using two methods as follows. Method 1 is only differentiating both sides of the equation. Additionally, Method 2 is differentiating both sides of the equation and then substituting the original equation into the second-order system. From the general form of the deviation curvatures calculated using each method, the analytical results are obtained as (A), (B), and (C). (A) Equilibrium points are Jacobi unstable for both methods; however, the type of equilibrium points is different. In Method 1, the equilibrium point is a nonisolated fixed point. Conversely, the equilibrium point is a saddle point in Method 2. (B) When there is a Jacobi stable region, the size of the Jacobi stable region in the Method 1 is different from that in Method 2. Especially, the Jacobi stable region in Method 1 is always larger than that in Method 2. (C) When there are multiple equilibrium points, the Jacobi stable region always exists in the nonequilibrium region located between the equilibrium points. These results are confirmed numerically using specific dynamical systems, which are given by the logistic equation and its evolution equation with the Hill function. From the results of (A) and (B), differences in types of equilibrium points affect the size of the Jacobi stable region. From (C), the Jacobi stable regions appear as nonequilibrium regions where the equations cannot be linearized.
Improving acid-stressed anaerobic digestion processes with biochar - towards a combined biomass and carbon management system
Authors: Hu Jiahui , Wachendorf Michael , Gwenzi Willis , Joseph Ben , Stenchly Kathrin , Kaetzl Korbinian
Published: February 2024

Interest in biochar as an additive to enhance anaerobic digestion (AD) has grown in the context of biomass cascading use and the 2050 net-zero goal. However, few studies have investigated the effects of biochar on AD from a biochar production perspective, including biomass feedstocks and pyrolysis temperatures. To valorise biomass and better understand the mechanisms and environmental implications of using biochar in AD, this study investigated the effects of distinct biochar types on AD under acid stress-induced process inhibition using batch tests. The results demonstrated that biochar can mitigate acid stress and enhance the methane production rate. The kinetic rate constant of methane production is positively related to the buffer capacity of the tested biochars (R
2 = 0.88). The choice of feedstocks is a crucial factor (P = 0.003), particularly the best-performing biochars derived from raw grass silage. In contrast, the pyrolysis temperature effect was less significant (P = 0.18). Furthermore, the analysis of biochar indicates that the alkali (K) and alkaline earth (Ca, Mg) metals contained in biochar may be one of the important factors contributing to buffer capacity (R
2 = 0.82 to 0.86). Hence, buffer capacity is a crucial quality criteria when evaluating biochar for AD applications. Raw grass silage biochars are promising for acid stress mitigation due to their high buffer capacity, while carbon-rich woody biochars have high CO2 sequestration potential. A compromise between mitigating acid stress and sequestering carbon is the use of pre-treated grass biochar. Overall, the use of biochar-enriched digestate offers a potential way to close material loops and complete the biomass-to-biochar value chain.