bluuebunny/crossref_metadata_2025 huggingface dataset:
Generalizing Bayesian phylogenetics to infer shared evolutionary events
Authors: Oaks Jamie R. , Wood Perry L. , Siler Cameron D. , Brown Rafe M.
Published: July 2022

Many processes of biological diversification can simultaneously affect multiple evolutionary lineages. Examples include multiple members of a gene family diverging when a region of a chromosome is duplicated, multiple viral strains diverging at a “super-spreading” event, and a geological event fragmenting whole communities of species. It is difficult to test for patterns of shared divergences predicted by such processes because all phylogenetic methods assume that lineages diverge independently. We introduce a Bayesian phylogenetic approach to relax the assumption of independent, bifurcating divergences by expanding the space of topologies to include trees with shared and multifurcating divergences. This allows us to jointly infer phylogenetic relationships, divergence times, and patterns of divergences predicted by processes of diversification that affect multiple evolutionary lineages simultaneously or lead to more than two descendant lineages. Using simulations, we find that the method accurately infers shared and multifurcating divergence events when they occur and performs as well as current phylogenetic methods when divergences are independent and bifurcating. We apply our approach to genomic data from two genera of geckos from across the Philippines to test if past changes to the islands’ landscape caused bursts of speciation. Unlike previous analyses restricted to only pairs of gecko populations, we find evidence for patterns of shared divergences. By generalizing the space of phylogenetic trees in a way that is independent from the likelihood model, our approach opens many avenues for future research into processes of diversification across the life sciences.
Cell atlas of the human ocular anterior segment: Tissue-specific and shared cell types
Authors: van Zyl Tavé , Yan Wenjun , McAdams Alexi M. , Monavarfeshani Aboozar , Hageman Gregory S. , Sanes Joshua R.
Published: July 2022

The anterior segment of the eye consists of the cornea, iris, ciliary body, crystalline lens, and aqueous humor outflow pathways. Together, these tissues are essential for the proper functioning of the eye. Disorders of vision have been ascribed to defects in all of them; some disorders, including glaucoma and cataract, are among the most prevalent causes of blindness in the world. To characterize the cell types that compose these tissues, we generated an anterior segment cell atlas of the human eye using high-throughput single-nucleus RNA sequencing (snRNAseq). We profiled 195,248 nuclei from nondiseased anterior segment tissues of six human donors, identifying >60 cell types. Many of these cell types were discrete, whereas others, especially in the lens and cornea, formed continua corresponding to known developmental transitions that persist in adulthood. Having profiled each tissue separately, we performed an integrated analysis of the entire anterior segment, revealing that some cell types are unique to a single structure, whereas others are shared across tissues. The integrated cell atlas was then used to investigate cell type–specific expression patterns of more than 900 human ocular disease genes identified through either Mendelian inheritance patterns or genome-wide association studies.
Sox9 directs divergent epigenomic states in brain tumor subtypes
Authors: Sardar Debosmita , Chen Hsiao-Chi , Reyes Amanda , Varadharajan Srinidhi , Jain Antrix , Mohila Carrie , Curry Rachel , Lozzi Brittney , Rajendran Kavitha , Cervantes Alexis , Yu Kwanha , Jalali Ali , Rao Ganesh , Mack Stephen C. , Deneen Benjamin
Published: July 2022

Epigenetic dysregulation is a universal feature of cancer that results in altered patterns of gene expression that drive malignancy. Brain tumors exhibit subtype-specific epigenetic alterations; however, the molecular mechanisms responsible for these diverse epigenetic states remain unclear. Here, we show that the developmental transcription factor Sox9 differentially regulates epigenomic states in high-grade glioma (HGG) and ependymoma (EPN). Using our autochthonous mouse models, we found that Sox9 suppresses HGG growth and expands associated H3K27ac states, while promoting ZFTA-RELA (ZRFUS) EPN growth and diminishing H3K27ac states. These contrasting roles for Sox9 correspond with protein interactions with histone deacetylating complexes in HGG and an association with the ZRFUSoncofusion in EPN. Mechanistic studies revealed extensive Sox9 and ZRFUSpromoter co-occupancy, indicating functional synergy in promoting EPN tumorigenesis. Together, our studies demonstrate how epigenomic states are differentially regulated in distinct subtypes of brain tumors, while revealing divergent roles for Sox9 in HGG and EPN tumorigenesis.
Influence of nuclear quantum effects on the electronic properties of amorphous carbon
Authors: Kundu Arpan , Song Yunxiang , Galli Giulia
Published: July 2022

We carry out quantum simulations to study the physical properties of diamond-like amorphous carbon by coupling first-principles molecular dynamics with a quantum thermostat, and we analyze multiple samples representative of different defective sites present in the disordered network. We show that quantum vibronic coupling is critical in determining the electronic properties of the system, in particular its electronic and mobility gaps, while it has a moderate influence on the structural properties. We find that despite localized electronic states near the Fermi level, the quantum nature of the nuclear motion leads to a renormalization of the electronic gap surprisingly similar to that found in crystalline diamond. We also discuss the notable influence of nuclear quantum effects on band-like and variable-hopping mechanisms contributing to electrical conduction. Our calculations indicate that methods often used to evaluate electron–phonon coupling in ordered solids are inaccurate to study the electronic and transport properties of amorphous semiconductors composed of light atoms.
Corpus RLD
Authors: Manteca Ángel Alonso-Cortés , Ayuga Juan Manuel Díaz , Fernández–Pampillón Cesteros Ana María
Published: July 2022

Abstracta

Este artículo explica el corpus RLD, una recopilación de sentencias dictadas por jueces del Tribunal Supremo y del Tribunal Constitucional que han optado por el uso de diccionarios y la gramática del español como autoridad lingüística en la redacción de dichas sentencias judiciales. Las cuatro fases seguidas para la construcción del corpus –(i) diseño, (ii) implementación, (iii) revisión y (iv) publicación– se explican detalladamente. El objetivo del corpus, que incluye 1940 sentencias emitidas entre los años 2012 y 2018, es proporcionar una muestra de datos representativos y empíricamente satisfactorios del empleo de los diccionarios y la gramática como autoridad lingüística en la jurisprudencia española. Este corpus viene a cubrir un vacío en los estudios de lengua y derecho: por una parte, la ausencia de grandes corpus de textos jurídicos compartidos, disponibles para cualquier investigador o grupo de investigación interesado; y, por otra, la necesidad de analizar empíricamente el uso del diccionario y la gramática en las sentencias del Tribunal Supremo y del Tribunal Constitucional.
Phase field crystal simulation of gap healing at nanoscale
Authors: Li Yi-xuan , Gao Ying-Jun , Yi Xiao-Ai , Deng Qian-Qian , Kun Liao , Huang Zong-Ji , Luo Zhi-Rong
Published: July 2022

The phase field crystal method is used to simulate the healing process of the central gap of three-dimensional bcc crystal material under compressive strain at the atomic level. It is found that during the healing process of the central gap, the gap protrudes at both ends of it, leading to dislocation nucleation and vacancy formation. Through the mechanism of dislocation nucleation and dislocation emission, the thickness of gap is reduced layer by layer, and finally the connection and closure of the lattice atoms on up and down surface of the gap are achieved, and the surface healing of the central gap is realized. According to the sharpening and passivation mechanism of the lattice atomic planes at both ends of the gap, the elliptic shape gap is approximated to calculate and analyze the influence of the change of stress intensity factor during the gap healing, and the critical condition of the gap dislocation emission is determined.
Surface induced melting of long Al nanowires: phase field model and simulations for pressure loading and without it
Authors: Javanbakht Mahdi , Eskandari Shekoofeh Salehi , Silani Mohammad
Published: July 2022

In this paper, melting of long Al nanowires is studied using a phase field model in which deviatoric transformation strain described by a kinetic equation produces a promoting driving force for both melting and solidification and consequently, a lower melting temperature is resolved. The coupled system of the Ginzburg–Landau equation for solidification/melting transformation, the kinetic equation for the deviatoric transformation strain and elasticity equations are solved using the COMSOL finite element code to obtain the evolution of melt solution. A deviatoric strain kinetic coefficient is used which results in the same pressure as that calculated with the Laplace equation in a solid neglecting elastic stresses. The surface and bulk melting temperatures are calculated for different nanowire diameters without mechanical loading which shows a good agreement with existing MD and analytical results. For radii R > 5 nm, a complete surface solid-melt interface is created which propagates to the center. For smaller radii, premelting occurs everywhere starting from the surface and the nanowire melts without creating the interface. The melting rate shows an inverse power relationship with radius for R < 15 nm. For melting under pressure, the model with constant bulk modulus results in an unphysical parabolic variation versus pressure in contrast to the almost linear increase of the melting temperature versus pressure from known MD simulations. Such drawback is resolved by considering the pressure dependence of the bulk modulus through the Murnaghan’s equation due to which an almost linear increase of the melting temperature versus pressure is obtained. Also, a reduction of the interface width and a significant increase of the melting rate versus pressure are found. The presented model and results allow for a better understanding of the premelting and melting of different metallic nanowires with various loading conditions and structural defects.
Computability of topological pressure on compact shift spaces beyond finite type*
Authors: Burr Michael , Das Suddhasattwa , Wolf Christian , Yang Yun
Published: July 2022

We investigate the computability (in the sense of computable analysis) of the topological pressure P
top(ϕ) on compact shift spaces X for continuous potentials

ϕ
:
X
→
R

. This question has recently been studied for subshifts of finite type (SFTs) and their factors (sofic shifts). We develop a framework to address the computability of the topological pressure on general shift spaces and apply this framework to coded shifts. In particular, we prove the computability of the topological pressure for all continuous potentials on S-gap shifts, generalised gap shifts, and particular beta-shifts. We also construct shift spaces which, depending on the potential, exhibit computability and non-computability of the topological pressure. We further prove that the generalised pressure function (X, ϕ) ↦ P
top(X, ϕ|
X
) is not computable for a large set of shift spaces X and potentials ϕ. In particular, the entropy map X ↦ h
top(X) is computable at a shift space X if and only if X has zero topological entropy. Along the way of developing these computability results, we derive several ergodic-theoretical properties of coded shifts which are of independent interest beyond the realm of computability.
Orbital stability of a sum of solitons and breathers of the modified Korteweg–de Vries equation
Authors: Semenov Alexander
Published: July 2022

In this article, we prove that a sum of solitons and breathers of the modified Korteweg–de Vries equation (mKdV) is orbitally stable. The orbital stability is shown inH2. More precisely, we will show that if a solution of mKdV is close enough to a sum of solitons and breathers with distinct velocities att= 0 in theH2sense, then it stays close to this sum of solitons and breathers for any timet⩾ 0 in theH2sense, up to space translations for solitons or space and phase translations for breathers, provided the condition that the considered solitons and breathers are sufficiently decoupled from each other and that the velocities of the considered breathers are all positive, except possibly one. The constants that appear in this stability result do not depend on translation parameters. From this, we deduce the orbital stability of any multi-breather of mKdV, provided the condition that the velocities of the considered breathers are all positive, except possibly one (the condition about the decoupling of the considered solitons and breathers between each other is not required in this setting). The constants that appear in this stability result depend on translation parameters of the considered solitons and breathers.
Partial regularity for an exponential PDE in crystal surface models
Authors: Xu Xiangsheng
Published: July 2022

We study regularity properties of weak solutions to the boundary value problem for the equation −Δρ + au = f in a bounded domain

Ω
⊂

R

N

, where

ρ
=

e

−
div

|
∇
u

|

p
−
2

∇
u
+

β

0

|
∇
u

|

−
1

∇
u

. This problem is derived from the mathematical modelling of crystal surfaces. It is known that the exponential term can be a measure-valued function. In this paper we obtain a partial regularity result, which asserts that there exists an open subset Ω0 ⊂ Ω such that |Ω\Ω0| = 0 and the exponential term is locally bounded in Ω0. Furthermore, if x
0 ∈ Ω\Ω0, then ρ vanishes of N + 2 − ɛ order at x
0 for each ɛ ∈ (0, 2).
Nonlinear dynamic buckling and vibration of thermally post-buckled temperature-dependent FG porous nanobeams based on the nonlocal theory
Authors: Salari E , Ashoori A R , Sadough Vanini S A , Akbarzadeh A H
Published: July 2022

In this paper, nonlinear dynamic snap-through buckling and vibration behavior of the thermally post-buckled functionally graded (FG) porous nanobeams subjected to static and sudden mechanical loads are investigated utilizing the nonlocal elasticity theory. The physical properties of the nanobeam are considered to be functions of temperature based on the Touloukian model. In addition, to describe the FG porous materials, two different patterns of porosity distribution are adopted using trigonometric functions through the thickness of the nanobeam. The equations of motion in conjunction with the von-Kármán nonlinear assumption are established in the framework of Hamilton’s principle. By employing the Chebyshev-Ritz procedure, the nonlinear equations are discretized for three types of edge supports. Following that, the cylindrical arc-length technique is employed to assess the vibrational responses of the post-buckled nanobeam during static snap-through buckling. To evaluate the nonlinear dynamic buckling of the graded nanobeam under a sudden dynamic load, the Newmark time integration scheme together with the Newton-Raphson iterative method are utilized. Next, by means of the Budiansky-Roth criterion and the phase-plane approach, the dynamic snap-through loads are identified. After validating the developed mathematical model, a comprehensive investigation is carried out to determine the role of various physical and geometrical parameters on the dynamic snap-through buckling and vibration characteristics of the post-buckled FG nanobeams.
Study of the structural, electronic, mechanical, electro-thermal and optical properties of double perovskite structures Cs2SbAgX6, (X = I, Br, or Cl)
Authors: Jafar Aqel Mashot , Khalaph Kawther A , Al Husseini Hussein B
Published: July 2022

In the double perovskites structures, Cs2SbAgX6, X is I, Br, or Cl, the structural, electronic, thermodynamic, thermoelectric and optical, properties have been investigated by using the density functional theory (DFT) correction method. The XRD structural study exhibits that the double perovskite structures are stable in the cubic phase structures. Elastic parameters reveal all structures to be very hard and ductile in nature. The energy band profiles display indirect band-gap of semiconductor behavior for the structures Cs2SbAgX6; X is Cl or Br, while exhibiting metallic behavior of the structure Cs2SbAgI6. The thermoelectric transport properties were verified in the temperature range (5–1000) K, which includes electrical conductivity, thermal conductivity, Seebeck coefficients, and the figure of merit, ZT, for Cs2SbAgX6 structures. These structures exhibit high thermal conductivity with good Seebeck coefficients at room temperature. The semiconducting structure, Cs2SbAgBr6, has appropriate band gaps and best Seebeck coefficients; therefore, it has the best values of ZT reached 0.000 16 at 1000 K, which means the suitable structure for employment in thermoelectric and spintronic devices applications. The optical properties of these structures exhibit that the absorption effective region at the Visible-Ultraviolet region, therefore these materials are suitable in the applications of solar cells and optoelectronic devices.
CW and Q-switched operations of a Tm3+:YAP laser at 1892–1994 nm In-band fiber-laser pumped at 1670 nm
Authors: Antipov O L , Dobrynin A A , Getmanovskiy Yu A , Sharkov V V , Shestakova I A , Balabanov S S , Larin S V
Published: July 2022

Tm3+:YAP lasers in-band fiber-laser pumped at 1670 nm with a linear or L-shaped cavity were studied in CW, actively and passively Q-switched regimes. High-efficiency CW and repetitively-pulsed operations were registered at three spectral regions: 1987–1994 nm, 1935–1941 nm and 1892–1897 nm. The transition between these three spectral regions was achieved by controlling the pump power and the output mirror in a laser cavity. The highest CW output power that was achieved without degrading the beam quality was 12.2 W at the 52% slope efficiency with respect to the incident pump. Acousto-optically Q-switched operation with the average power of 9.8 W at the 20 kHz pulse repetition rate (PRR) and 6 W at 3 kHz PRR was achieved, the pulse energy was scaled up to 2.7 mJ at 0.5 kHz PRR. The passive Q-switch operation at 1935–1938 nm was obtained using a Cr2+:ZnSe saturable absorber; the pulse energy reached 150 µJ at the 20 kHz PRR
Nuclear data libraries for IFMIF-DONES neutronic calculations
Authors: Mendoza E. , Cano-Ott D. , Ibarra A. , Mota F. , Podadera I. , Qiu Y. , Simakov S.P.
Published: July 2022

International Fusion Materials Irradiation Facility-DEMO Oriented NEutron Source (IFMIF-DONES) is an installation aimed to irradiate with a high neutron flux materials relevant for the construction of the DEMOnstration fusion power plant (DEMO), in order to study the damage due to irradiation. Neutrons are generated using a 40 MeV and 125 mA deuteron beam impinging on a thick liquid lithium target. With these characteristics, damage due to irradiation comparable to that in the first wall of a fusion power reactor is achieved. In this paper we investigate the differences in the neutronic calculations of the IFMIF-DONES design when using different nuclear data libraries. We first studied the differences in neutron production due to Li(d, xn) reactions between different models and evaluations, comparing the different results with experimental data. Additionally, we tested the performance of the MCNP6.2 and Geant4 Monte Carlo codes when using deuteron incident data libraries. Then, we performed neutronic calculations of the IFMIF-DONES design using the most reliable Li(d, xn) neutron production models available, which are the FZK-2005 and JENDL/DEU-2020 evaluations according to the results obtained in the first part of the study. Thus, the differences in these evaluations are propagated to different neutronic calculation results: neutron flux, primary displacement damage, gas production, and heating in the materials to be irradiated. Finally, we also carried out these same neutronic calculations while using different nuclear data libraries for the neutron transport.
Symmetry-driven network reconstruction through pseudobalanced coloring optimization
Authors: Leifer Ian , Phillips David , Sorrentino Francesco , Makse Hernán A
Published: July 2022

Symmetries found through automorphisms or graph fibrations provide important insights in network analysis. Symmetries identify clusters of robust synchronization in the network which improves the understanding of the functionality of complex biological systems. Network symmetries can be determined by finding a balanced coloring of the graph, which is a node partition in which each cluster of nodes receives the same information (color) from the rest of the graph. In recent work we saw that biological networks such as gene regulatory networks, metabolic networks and neural networks in organisms ranging from bacteria to yeast and humans are rich in fibration symmetries related to the graph balanced coloring. Networks based on real systems, however, are built on experimental data which are inherently incomplete, due to missing links, collection errors, and natural variations within specimens of the same biological species. Therefore, it is fair to assume that some of the existing symmetries were not detected in our analysis. For that reason, a method to find pseudosymmetries and repair networks based on those symmetries is important when analyzing real world networks. In this paper we introduce the pseudobalanced coloring (PBCIP) problem, and provide an integer programming formulation which (a) calculates a PBCIP of the graph taking into account the missing data, and (b) optimally repairs the graph with the minimal number of added/removed edges to maximize the symmetry of the graph. We apply our formulation to the C. elegans connectome to find pseudocoloring and the optimal graph repair. Our solution compares well with a manually curated ground-truth C. elegans graph as well as solutions generated by other methods of missing link prediction. Furthermore, we provide an extension of the algorithm using Bender’s decomposition that allows our formulation to be applied to larger networks.
Design optimization of engine mounting system for a modular electric vehicle platform with different powertrain characteristics
Authors: Hazra Sandip , Janardhan Reddy K
Published: July 2022

In recent days, there is much focus on the modularity of the platform to reduce the cost and improve the system-level design efficiency. In this paper, a study has been done for various non-linear input torque (different powertrain) and optimization with a modular powertrain mounting system where only stiffness is varied to achieve the optimization goal. Here, the optimization goals are maximization of kinetic energy distribution to improve the decoupling rate and minimization of powertrain CoG movement under torque. HEEDS and MATLAB optimization tools are used for analysis. First, three different powertrains are considered individually for optimization. Then, all three powertrains for a particular location on the modular platform are optimized with different mount stiffness. Different mount stiffnesses are chosen in such a way that the stiffness can be achieved only by hardness adjustment or minimum design modification without any change in complete mount design. Proposed results show that a properly chosen mounting system can address the platform modularity quite quickly.
Integrated artificial intelligence and life cycle assessment to predict environmental and economic impacts for natural gas hybrid electric vehicle with multi-dimension
Authors: Miao Yang , Qiu Zaihui , Zhang Meng , He Baofeng , Zhang Xiaolu , Li Miao
Published: July 2022

The automotive industry plays very significant role in Chinese industry. but higher energy consumption and higher pollution accompanying with the vehicle’s industry chain as well. natural gas for vehicles has the characteristics of cleanness, economy and reliability. Therefore, the hybrid vehicle with both advantages of natural gas and electricity has great potential. However, it is unclear that the promotion of natural gas / electric hybrid vehicles (NGEHV) could really achieve energy saving and emission reduction. In this paper, consider all stages vehicle production, transportation, use, maintenance and scrap recovery, the possession is decomposed into three aspects: resource attributes, energy attributes and environmental attributes. An composition analysis method of NGEHV is constructed. A life cycle assessment(LCA), in the view of Cradle-to-Grave, of environmental impact for natural gas / electric hybrid vehicles is established. Based on BP neural network, prediction information of traditional vehicles and NGEHV on various environmental factors and costs are obtained. It could provide scientific basis for the sustainable advancement and decision-making for government.
Eddy Current Mapping Technology for Residual Stress and Surface Hardness Evaluation in Laser Hardened Steels
Authors: Wang N , He C F , Liu X C
Published: July 2022

Laser quenching can achieve surface hardening with narrow heat affected zone while without affecting the surface roughness of the material. Therefore, the laser quenching technique is increasingly applied for surface hardening in key components such as precision gear, guide rail, etc. Phase transformation and thermal diffusion occur in the process of laser quenching, resulting in change of microstructures and residual stress distribution in the surface layer material. To evaluate the quality of the laser-hardened material of 45and 30Cr steel, eddy current mapping technology is employed in this study to characterize the residual stress and surface hardness. First, C-scan eddy current inspection was performed to the laser hardened region. The mapping results of the impedance parameters clearly show the boundary between the hardened zone and the matrix. Second, X-ray diffraction system and Vickers hardness tester were alternatively used to analyze the distribution of surface hardness and residual stress. Third, the correlation between the individual eddy current parameter and the surface hardness (or residual stress) is investigated by simple linear regression tool. The impedance amplitude demonstrates good linear dependencies on both the surface hardness and residual stress. Therefore, the proposed eddy current mapping technology is capable of mapping the distribution of surface hardness (related with microstructures) or the residual stress in laser hardened ferromagnetic components.
Design of advanced micro-magnetic sensors for various applications
Authors: Wang Xianxian , Liu Xiucheng , Liu Xin , Shang Wanli , Wang Shanshan , He Cunfu
Published: July 2022

The state of the microstructures determines both the mechanical properties (hardness, yield strength, elongation, etc.) and micro-magnetic properties (magnetic Barkhausen noise (MBN), incremental permeability (IP), etc.). The non-destructive nature of the micro-magnetic testing technology facilitate it be a valuable tool for quality control in the manufacturing of ferromagnetic components. In the implementation of micro-magnetic testing, the functions and the geometry of the sensors need be customized for specific target properties and components. In this paper, four types of advanced or multifunctional sensors are presented and applied for micro-magnetic testing. First, a multifunctional sensor is developed for flat surface. Unique intermittent magnetizing method using superimposed magnetic fields of high and low frequencies enable the sensor to measure the magnetic Barkhausen noise, incremental permeability, eddy currents, tangential magnetic field and main flux. Second, to conduct magnetic Barkhausen noise testing at the inner corner of V-shape bending plate, a miniaturized sensor with U-shape roller magnetizer is designed to perfect contact with the corner region. Third, read head of a magnetic tape player is revised to act as high-lateral-resolution (up to 500μm) sensor for magnetic Barkhausen noise measurement in ferromagnetic film. Fourth, a slender probe is developed and embedded into an anti-bulking fixture that is clamped onto the flat specimen. With the slender probe together with the special fixture, the dependency of the magnetic Barkhausen noise on the compressive and tensile stress is first experimentally observed in a single flat specimen under continuous load.
CNC Machining Centre Thermal Error Prediction from Temperature Sensors Using Autoencoder-Augmented Long Short Term Memory Networks
Authors: Marei Mohamed , Li Weidong
Published: July 2022

To counteract thermal error due to material deformation in multi-axis heavy-duty CNC machining applications, this paper presents an approach based on Autoencoder-Augmented Long Short Term Memory deep learning models. The model predicts the z-axis offset of machine tools, in an idle state, with up to 96% accuracy, from ambient temperature sensor readings. By enabling a Long Short-Term Memory (LSTM) algorithm to learn time dependencies across input features and past output values with a fifth-order lag, a sequence-to-sequence regression problem is formulated. The model objective is to predict the z-axis thermal offset as an output from temperature sensor inputs. To reduce input data redundancy, the algorithm also leverages an Autoencoder to learn a reduced dimension feature representation for the input data. The reduction in input dimensionality achieves a considerable reduction in computation effort, measured in units of time, without compromising the prediction accuracy. The performance of the proposed technique is evaluated on a subset of the recorded data, and the model is benchmarked against several techniques from the literature. The results and qualitative evaluation demonstrate the superiority of the proposed approach at generating accurate predictions of the z-axis error of the system and, consequently, reducing the control error.
The Design of Large-aperture HFCVD Diamond-coated Drawing Die Preparation System and Experimental Study on Its Application
Authors: Fang Shanxiang , Zhang Qinjian , Ji Shizhe
Published: July 2022

As a new type of die, HFCVD diamond-coated drawing die registers a great application prospects and market potential because of its performance advantages. This study mainly focuses on the preparation system of diamond coating for large-aperture drawing die. According to the finite element analysis of the temperature field of the die base on HFCVD process, hot filament parameters on the temperature distribution of the die base is studied. And on the basis of the sdudy, a new HFCVD coating mold preparation system with rotating U-shape groove is designed, which can produce more uniform coating. The deposition experiments were carried out on the inner wall of the drawing die by the HFCVD coating mold preparation system. The cross-sectional morphology, surface morphology and Raman spectrogram of the diamond coating show that the thickness of the diamond coating is uniform and the quality is satisfactory. This provides reference for the application of the large-aperture diamond-coated drawing die.
An Adsorption Robot for Pipeline Inspection of Gas Insulation Switchgear
Authors: Wensheng Li , Kaixuan Li , Ming Nie , Wei Wang , Liqiang Zhong , Xiaoming Mai , Hao Wu , Hao Mo
Published: July 2022

In order to enable a robot to do the omni-directional mobility for inspection in the pipeline of Gas Insulation Switchgear, a negative pressure adsorption pipeline robot is designed. Firstly, the mechanical structure was designed for the omni-directional mobility based on the negative pressure adsorption. The internal surface motion model of the pipeline robot was built, and a variable adsorption control method was proposed by mechanical analysis. Simulations and experiments showed that the robot could steadily adsorb on any position of the pipeline, which validated the capability of omni-directional mobility for the designed robot. This robot can be used for inspection of the Gas Insulation Switchgear in electric power industry in the near future.
Selection of measurement parameters using the DiagBelt magnetic system on the test conveyor
Authors: Olchówka D , Blażej R , Jurdziak L
Published: July 2022

The DiagBelt system is the diagnostics device for assessment of a technical condition of conveyor belts. The following paper concerns the magnetic module dedicated for monitoring of belts with steel cords. The system allows scanning of belts with different cord diameters and their density. The speed of the belt also may vary depending on the operating conveyor. Additionally, the system user can change measurement sensitivity and the distance between the measuring probe and the cord. The measurement allowed to determine values of these parameters of which test results are the most reliable. In practice, this enables faster and more accurate assessment of a belt condition, which plays a significant role in the planning maintenance operations. It has a good impact on the continuity of belt operation and belt conveyors reliability. Therefore, it improves the reliability of the whole mining transport system.
The smart design process of seats mounting for public transport vehicles
Authors: Zawadzki P , KŻywicki  , Krajanowski-Kaleta J , Promiński R , Jankowiak T , Szymański S , Szymański M , Mróz A
Published: July 2022

The paper presents a semi-automatic method supporting designers in the process of designing interior construction elements for mass communication vehicles. The use of special, generative CAD models, as well as the recording and implementation of engineering knowledge within KBE methods, has enabled the development of a new way of designing dedicated seat attachments. The new solution has allowed to shorten the design time, increase the standardization of manufactured components and limit the possibility of making mistakes by designers. The example described in the work was developed in the 3DExperience environment with Catia software.
Numerical modelling of concrete-filled aluminium alloy 6082-T6 columns under axial compression
Authors: Georgantzia Evangelia , Ali Shafayat Bin , Gkantou Michaela , Kamaris George S , Kot Patryk , Hashim Khalid
Published: July 2022

Aluminium alloys are characterised by numerous benefits, such as ease of fabrication, good strength-to-weight ratio, attractive appearance and high corrosion resistance. On the other hand, aluminium has low Young’s Modulus and as a result, it is susceptible to structural instability phenomena that can subsequently affect the structural integrity. Improved strength and stiffness can be achieved by combining aluminium alloys with concrete. The present work investigates numerically the response of concrete-filled aluminium tubular members under axial compression. In particular, 6082-T6 extruded aluminium alloy rectangular and square hollow sections filled with C30 concrete are examined. Finite element models are developed accounting for geometric and material non-linearities. Upon validation against experimental data, the finite element models are used to conduct a thorough parametric study over a wide range of structural members likely to occur in practice to investigate their structural behaviour under axial compression. The obtained load capacities are discussed and remarks on the structural response and on the buckling behaviour are reported. Design recommendations for the buckling strength of concrete-filled aluminium tubular columns on the basis of the numerical analyses are also made.
Study on the effects of laser quenching power and scanning speed on the property of cast iron
Authors: Wang S , Yan S , Lin J , Batako A D
Published: July 2022

The laser surface quenching power, scanning speed, and spot area have significant effect on the properties of the laser quenched materials. The effects of laser quenching power and scanning speed on the tribological, vibration, and noise performance of gray cast iron (HT250) are studied in this paper. Keeping the laser quenching spot constant, 12 cast iron discs are laser quenched by changing the laser quenching power and scanning speed. Various mechanical, tribological, and dynamical testing equipment are used to characterize the properties of the laser quenched cast iron discs, in terms of the surface hardness, residual stress, friction coefficient, and frictional vibrations and noise of the cast iron discs. The experimental results show that after laser surface quenching, the surface hardness of the cast iron disc has been increased more than 4 times, the residual stress on the disc surface is changed from tensile stress to compressive stress, the friction coefficients of the laser quenched cast iron discs have been significantly increased, and the vibration and noise generated from the laser quenched cast iron discs have been significantly changed. This research has significance to the improvement of the surface performance of automotive brake discs and the control of braking frictional vibrations and noise.
Surface Finish and Property Evaluation of Direct Metal Laser Sintered (DMLS) Al-Si-10Mg alloy
Authors: Ashwath P. , Anthony Xavior M. , Jeyapandiarajan P. , Joel J. , Batako Andre
Published: July 2022

Recently, Additive Manufacturing (AM) technique is widely recognized by engineering sectors for its novel capability to manufacture components directly from a Computer-Aided Model (CAM). Direct Metal Laser Sintering (DMLS) is an upcoming modernization among different AM techniques. DMLS is one of the AM techniques attuned to produce the three-dimensional components or expensive component by layer-by-layer powder deposition and laser sintering avoiding utilization of any alternative additional processes. Current research work focus on fabricating an Al-Si-10Mg aluminium alloy by DMLS process which is studied for the influence of specimen geometry, surface finish and build orientation on the mechanical strength. The importance of the sample studied for the geometry and surface finish is quite necessary specifically for dynamic applications.
The properties of stainless steel 17-4PH produced by a low-cost additive manufacturing technique, the Markforged MetalX™
Authors: Burgess A , Dodd R , Radwani M , Opoz T T , Tammas-Williams S
Published: July 2022

The lower capital and running cost of the Markforged Metal X™ platform, in comparison to competing metal additive manufacturing systems, makes it a highly attractive proposition for several industries. The unusual print, then sinter, process also has the potential to avoid many of the metallurgy issues that can arise using more typical additive manufacturing, which relies on melting to bind the material. However, the mechanical properties of the material produced must be well understood. In this paper, the properties of 17-4PH stainless steel samples produced by the Metal X™ are documented following a systematic testing program, involving standard mechanical testing as well as material characterisation techniques. Significant differences were observed between the samples tested in differing orientations. This is thought to be due to the deposition process used to lay the material prior to sintering, which results in voids and surface stress concentrations that reduce the strength of the material. Heat treatments and surface machining were both found to improve the tensile properties of the material.
Modelling and automation of a process for obtaining coagulum in treatment of industrial
Authors: Safonyk A , Tarhonii I , Burduk A , Batako A
Published: July 2022

This paper present the development a model for obtaining a coagulant for the process of cleaning and discoloration of industrial waste water and the development of a PID automated system for wastewater treatment. The description of the processes taking place in an electro-coagulator is given along with the solution obtained by model. The influence of current on the concentration of divalent iron water temperature is investigated. The algorithm of two-circuit regulation of concentration of pollution in sewage with the feedback current between the coagulator plates and the concentration pollutants in the water entering the automated purification system is developed. The automated control system for wastewater treatment process with the implementation of the coagulant forecasting algorithm in relation to the input pollution concentration is developed. The control of current magnitude in the electro-coagulator with minimal electricity consumption was realized. It is planned to manage the system with the ability to change the performance of the entire installation in real time using the SCADA - system.
A LN2-based cryogenic system prototype for future PandaX experiment
Authors: Jiang Xinbei , Zhao Li , Wang Shaobo , Fu Jia , Wu Tianjie , Liu Jianglai
Published: July 2022

This paper describes results on R&D of an economical and
efficient cryogenic system prototype for future liquid xenon
detector. The test module of the prototype has a “coldhead”
attached to a copper rod, which is specially designed to transport
heat loads to a free-boiling liquid nitrogen bath. The performance
of the test module and commercial refrigerators is compared. The
module with an optimized copper rod has demonstrated more than
1500 W cooling power at 178 K. The temperature of the “cold
head” can be kept stable with an error of 0.02 K, its fluctuation
is within 0.1 K.
Monte Carlo study of the BSS2 calibration system using the PTW 23392 extrapolation chamber
Authors: Araújo L.F. , Behrens R. , Fonseca T.C.F.
Published: July 2022

The objective of the present work was to develop and validate a computational model of the Beta Secondary Standard type 2 (BSS2) system, with sources, filters and the PTW 23392 extrapolation chamber using MCNPx code. Simulations were performed to calculate the absorbed dose rate to tissue at null depth and 0.07 mm for the 85Kr, 90Sr/90Y and 147Pm beta radiation sources. The response curve was calculated by computing the energy deposited, at different depths, to the sensitive volume of the chamber. The deviations in the absorbed dose rate obtained using the MCNPx code compared to the calibration certificate data were found to be up to 2 %. Deviations up to 10 % were observed for the transmission factor calculated for all three beta sources. This work describes in detail the main parameters and common issues seeing when modelling an extrapolation chamber and three different beta standard sources.
Unprecedented climate extremes in South Africa and implications for maize production
Authors: Bradshaw Catherine D , Pope Edward , Kay Gillian , Davie Jemma C S , Cottrell Andrew , Bacon James , Cosse Adriana , Dunstone Nick , Jennings Stewart , Challinor Andrew , Chapman Sarah , Birch Cathryn , Sallu Susannah M , King Richard , Macdiarmid Jennie
Published: July 2022

Maize is the most important crop grown in South Africa, but yields can be severely reduced by extreme high summer average temperatures and low precipitation, potentially adversely affecting both domestic consumption and regional food security exports. To help understand and manage climate risks to food security in Southern Africa it is essential to quantify the present-day likelihood and magnitude of climate extremes in South Africa’s maize-growing region and explore the potential for unprecedented climate conditions which would likely result in record low maize yields. We analyse a large ensemble of initialised climate model simulations, which provides almost 100 times as many plausible present-day summers as the equivalent observational dataset. We quantify the risk of unprecedented climate extremes affecting maize production in South Africa and examine the role of the El Niño-Southern Oscillation. We find that the South African maize region is at risk of experiencing record-breaking hot, cold, dry or wet events under current climatic conditions. We find that the annual chance of unprecedented high temperatures in South Africa is approximately 4%, increasing to 62% during very strong El Niño years. We also find that the chance of exceeding the present day seasonal high temperature record has increased across the 1979–2018 period, being five times more likely now than it was in 1980. These extreme events could result in a record-breaking number of days above the optimum, or even the maximum, temperature for maize production, and lead to more severe floods or droughts. Under climate change scenarios, the magnitude and frequency of climate extremes is projected to increase meaning that the unprecedented extremes studied here could become commonplace in the future. This suggests that significant investment is needed to develop adaptations that manage the climate-related risks to food systems now and build resilience to the projected impacts of climate change.
Universal fluctuations and ergodicity of generalized diffusivity on critical percolation clusters
Authors: Pacheco-Pozo Adrian , Sokolov Igor M
Published: July 2022

Despite a long history and a clear overall understanding of properties of random walks on an incipient infinite cluster in percolation, some important information on it seems to be missing in the literature. In the present work, we revisit the problem by performing massive numerical simulations for (sub)diffusion of particles on such clusters. Thus, we discuss the shape of the probability density function of particles’ displacements, and the way it converges to its long-time limiting scaling form. Moreover, we discuss the properties of the mean squared displacement (MSD) of a particle diffusing on the infinite cluster at criticality. This one is known not to be self-averaging. We show that the fluctuations of the MSD in different realizations of the cluster are universal, and discuss the properties of the distribution of these fluctuations. These strong fluctuations coexist with the ergodicity of subdiffusive behavior in the time domain. The dependence of the relative strength of fluctuations in time-averaged MSD on the total trajectory length (total simulation time) is characteristic for diffusion in a percolation system and can be used as an additional test to distinguish this process with disorder-induced memory from processes with otherwise similar behavior, like fractional Brownian motion with the same value of the Hurst exponent.
The SAGEX review on scattering amplitudes Chapter 6: Ambitwistor Strings and Amplitudes from the Worldsheet
Authors: Geyer Yvonne , Mason Lionel
Published: July 2022

Starting with Witten’s twistor string, chiral string theories have emerged that describe field theory amplitudes without the towers of massive states of conventional strings. These models are known as ambitwistor strings due to their target space; the space of complexified null geodesics, also called ambitwistor space. Correlators in these string theories directly yield compact formulæ for tree-level amplitudes and loop integrands, in the form of worldsheet integrals fully localized on solutions to constraints known as the scattering equations. In this chapter, we discuss two incarnations of the ambitwistor string: a ‘vector representation’ starting in space–time and structurally resembling the Ramond Neveu–Schwarz (RNS) superstring, and a four-dimensional twistorial version closely related to, but distinct from Witten’s original model. The RNS-like models exist for several theories, with ‘heterotic’ and type II models describing super-Yang–Mills and 10d supergravities respectively, and they manifest the double copy relations directly at the level of the worldsheet models. In the second half of the chapter, we explain how the underlying models lead to diverse applications, ranging from extensions to new sectors of theories, loop amplitudes and to scattering on curved backgrounds. We conclude with a brief discussion of connections to conventional strings and celestial holography.