bluuebunny/crossref_metadata_2025 huggingface dataset:
Fretting Fatigue Life Prediction of Dovetail Structure Based on Plastic Effect and Sensitivity Analysis of Influencing Factors
Authors: Zhou Jianjun , Yang Bowen , Li Shuaiyuan , Huo Junzhou
Published: May 2023

Micro relative sliding exists on the contact surface of the main primary equipment’s surface structures, resulting in serious fretting fatigue. The plastic effect causes serious fatigue to the structure under alternating loads. Existing fatigue life prediction models fail to fully consider the shortcomings of fretting and plastic effects, which causes the prediction results to be significantly different to real-lifeworld in engineering situations. Therefore, it is urgent to establish a fretting damage fatigue life prediction model of contact structures which considers plastic effects. In this study, a plastic fretting fatigue life prediction model was established according to the standard structural contact theory. The location of dangerous points was evaluated according to a finite element simulation. The cyclic load maximum stress value was compared with the fretting fatigue test data to confirm the error value, and the error between the proposed fretting fatigue life model and the test value was within 15%. Concurrently, we combined this with mass data analysis and research, as it is known that the contact zone parameters have an impact on fretting fatigue and affect the structural lifespan. With the help of ABAQUS, the fretting numerical calculation of the dovetail tenon model was carried out to analyze the sensitive factors affecting the fretting fatigue life of the dovetail tenon structure. By keeping the fretting load unchanged, the contact area parameters such as contact surface form, contact area width and friction coefficient were changed in order to calculate the fretting stress value, σfretting and the dovetail structure was improved to extend its fretting fatigue life. Finally, it was concluded that fretting fatigue was most sensitive to the width and contact form of the contact area. In actual engineering design, multiple factors should be considered comprehensively to determine a more accurate and suitable width and form of the contact area. For the selection of friction coefficient, on the premise of saving costs and meeting the structural strength requirements, the friction coefficient should be as small as possible, and the problem can also be solved through lubrication during processing.
Aspects of Austenitization for the Bearing Steel Induction Quenching Design
Authors: Nachazelova Daniela , Dlouhy Jaromir , Motycka Petr , Kotous Jakub
Published: May 2023

The dissolution of carbides during the heating to the quenching temperature has a significant effect on the martensite oversaturation and the resulting mechanical properties. The kinetics of dissolution can be influenced by various external factors. This work deals with monitoring the carbide dissolution utilizing dilatometer analysis. The austenitization of 100CrMnSi6-4 bearing steel in two initial states was compared—after accelerated spheroidization annealing and conventional soft annealing. The main objective was to determine the amount of undissolved cementite during austenitization in the temperature range where only austenite and cementite are present in the structure. The austenitization temperature determines the degree of cementite dissolution and, consequently, the carbon content in austenite and thus the final properties after quenching. The cementite dissolution was quantified from dilatometric curves and image analysis.
Experimental Study on the Influence of Transverse Crack on Chloride Ingress in Concrete Slab Track of High-Speed Railway
Authors: Liu Xiaochun , Li Haihua , Qi Min , Yang Yiyi , Zhu Zhihui , Yu Zhiwu
Published: May 2023

The concrete track slab and the base slab of the high-speed railway CRTS II track structure are prone to transverse cracks in the initial service period, which are subjected to environmental action and train load. In order to investigate the influence of transverse cracks on chloride ingress of concrete track slab and base slab in a coastal environment, drying-wetting cycle chloride erosion tests were carried out on reinforced concrete track slab and base slab specimens with cracks ranging from 0 mm to 0.6 mm, subjected to continuous bending moment. The chloride ion concentration of concrete along the depth direction was collected during the test process. The experimental results show that the chloride ion concentration of concrete at the crack section is much higher than that at the intact section, and it increases with the increase of crack width in the range of 0.2 mm to 0.6 mm. A chloride diffusion coefficient model of cracked concrete is proposed for slab track based on the experimental results, which can comprehensively consider the effects of surface chloride ion concentration, chloride binding effect, time-varying effect, temperature, relative humidity, and transverse crack width.
Clean H2 Production by Lignin-Assisted Electrolysis in a Polymer Electrolyte Membrane Flow Reactor
Authors: Rodríguez-Fernández José-Enrique , Rojo María , Avilés-Moreno Juan Ramón , Ocón Pilar
Published: May 2023

Biomass-derived products, such as lignin, are interesting resources for energetic purposes. Lignin is a natural polymer that, when added to the anode of an alkaline exchange membrane water electrolyser, enhances H2 production rates and efficiencies due to the substitution of the oxygen evolution reaction. Higher efficiencies are reported when different catalytic materials are employed for constructing the lignin anolyte, demonstrating that lower catalytic loadings for the anode improves the H2 production when compared to higher loadings. Furthermore, when a potential of −1.8 V is applied, higher gains are obtained than when −2.3 V is applied. An increase of 200% of H2 flow rates with respect to water electrolysis is reported when commercial lignin is used coupled with Pt-Ru at 0.09 mg cm−2 and E = −1.8 V is applied at the cathode. This article provides deep information about the oxidation process, as well as an optimisation of the method of the lignin electro-oxidation in a flow-reactor as a pre-step for an industrial implementation.
An Overview of Photocatalytic Membrane Degradation Development
Authors: Binazadeh Mojtaba , Rasouli Jamal , Sabbaghi Samad , Mousavi Seyyed Mojtaba , Hashemi Seyyed Alireza , Lai Chin Wei
Published: May 2023

Environmental pollution has become a worldwide issue. Rapid industrial and agricultural practices have increased organic contaminants in water supplies. Hence, many strategies have been developed to address this concern. In order to supply clean water for various applications, high-performance treatment technology is required to effectively remove organic and inorganic contaminants. Utilizing photocatalytic membrane reactors (PMRs) has shown promise as a viable alternative process in the water and wastewater industry due to its efficiency, low cost, simplicity, and low environmental impact. PMRs are commonly categorized into two main categories: those with the photocatalyst suspended in solution and those with the photocatalyst immobilized in/on a membrane. Herein, the working and fouling mechanisms in PMRs membranes are investigated; the interplay of fouling and photocatalytic activity and the development of fouling prevention strategies are elucidated; and the significance of photocatalysis in membrane fouling mechanisms such as pore plugging and cake layering is thoroughly explored.
Novel Graphene-Based Materials as a Tool for Improving Long-Term Storage of Cultural Heritage
Authors: Gorgolis George , Ziemann Steffen , Kotsidi Maria , Paterakis George , Koutroumanis Nikos , Tsakonas Christos , Anders Manfred , Galiotis Costas
Published: May 2023

The very serious problem of temperature and humidity regulation, especially for small and medium-sized museums, galleries, and private collections, can be mitigated by the introduction of novel materials that are easily applicable and of low cost. Within this study, archive boxes with innovative technology are proposed as “smart” boxes that can be used for storage and transportation, in combination with a nanocomposite material consisting of polyvinyl alcohol (PVA) and graphene oxide (GO). The synthesis and characterization of the PVA/GO structure with SEM, Raman, AFM, XRD, Optical Microscopy, and profilometry are fully discussed. It is shown that the composite material can be integrated into the archive box either as a stand-alone film or attached onto fitting carriers, for example, those made of corrugated board. By applying the PVA/GO membrane this way, even with strong daily temperature fluctuations of ΔT = ±24.1 °C, strong external humidity fluctuations can be reduced by −87% inside the box. Furthermore, these humidity regulators were examined as Volatile Organic Compounds (VOCs) adsorbers since gas pollutants like formic acid, formaldehyde, acetic acid, and acetaldehyde are known to exist in museums and induce damages in the displayed or stored items. High rates of VOC adsorption have been measured, with the highest ones corresponding to formic acid (521% weight increase) and formaldehyde (223% weight increase).
High-Temperature Oxidation Behaviour of CrSi Coatings on 316 Austenitic Stainless Steel
Authors: Gurtaran Mikdat , Zhang Zhenxue , Li Xiaoying , Dong Hanshan
Published: May 2023

In this study, a closed-field unbalanced magnetron sputtering system, which is environmentally friendly and has high deposition efficiency, was used to deposit CrSi coatings on 316 austenitic stainless steel. This system utilised separate Cr and Si targets, and the appropriate content of Cr and Si of the coatings was adjusted by changing the currents applied to the targets. A series of CrSi coatings with different Si/Cr ratios were produced, and their oxidation behaviour at elevated temperatures was investigated. By analysing the weight gain, surface morphology and microstructure, composition and phase constituents, the oxidation behaviour at 600 °C, 700 °C and 800 °C was investigated and the optimized coating to protect the stainless steel has been identified. The outcome of the research indicated that a small amount of Si (between 4–7 at.%) in Cr coatings is effective in protecting the austenitic stainless steel against oxidation at high temperatures, while a high Si content (around 10 at.% or more) makes the coating more brittle and prone to cracking or delamination during oxidation at 800 °C.
Editorial: New Advances in Nanomaterials
Authors: Wang Cheng , Yu Xiu , Liu Maning , Deng Zhifeng , Zhang Daohai , Zhang Haichang
Published: May 2023

In the past few years, people have been committed to a variety of properties and functional materials, among which are nanomaterials, which have been gradually developed in-depth [...]
Effect of Natural Aging on Cold Forming Performance of 2219 Aluminum Alloy
Authors: Li Zhi-Xin , Shi Yi-Long , Xu Luo-Peng , Jin Jia-Xin
Published: May 2023

To facilitate the manufacturing of the thin-walled components of 2219 aluminum alloy, the quenching–forming–aging (Q–F–A) process has been increasingly utilized. However, natural aging (NA) after quenching significantly affects the cold forming performance of this alloy. In this study, experiments are conducted to investigate the effect of NA time on the cold forming performance of 2219 aluminum alloy. The results indicate that NA can weaken the Portevin–Le Chatelier (PLC) effect, thereby reducing its influence on the cold forming performance of the alloy. The PLC effect becomes indistinct when the aging time reaches 2 years. The yield strength of 2219 aluminum alloy increases monotonically with aging time, while the elongation first increases rapidly and then decreases. After an aging time of 2 years, the yield strength increases by 28.6% from that of newly quenched alloys. The strain hardening index and hardening coefficient indicate that short-term NA (less than 4 days) increases the work hardening rate, while long-term NA reduces it. Microstructural analysis shows that the strengthening effect of NA on 2219 aluminum alloy is mainly due to the growth of G.P. zones and the precipitation of θ″ phases. The NA precipitation behavior can also cause the aggregation of solute atoms and weaken the PLC effect.
Fabrication of In Situ rGO Reinforced Ni–Al Intermetallic Composite Coatings by Low Pressure Cold Spraying with Desired High Temperature Wear Characteristics
Authors: Liu Zhikai , Lian Weiqi , Liu Cansen , Jie Xiaohua
Published: May 2023

In this study, the surface of aluminum powder was uniformly coated with in situ reduced graphene oxide (r-GO) sheets (Al/r-GO). The Ni powder, Al2O3 powder, and Al/r-GO powders were mixed uniformly in a mass ratio of 20:6:4. In situ rGO-reinforced Ni–Al intermetallic composite coatings were successfully prepared using low-pressure cold spraying and subsequent heat treatment. The microstructure and phase of the composite coatings were characterized using X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). The high-temperature wear test was conducted at 200 °C, 400 °C, and 600 °C to understand the mechanism. The results indicate that the in situ rGO-reinforced Ni–Al intermetallic composite coatings exhibit a 33.3% lower friction coefficient and 26% lower wear rate in comparison to pure Ni–Al intermetallic coatings, which could be attributed to the generation of an easy-shearing transferred film between the coating and grinding ball.
β-Cyclodextrin Nanosponges Inclusion Compounds Associated with Silver Nanoparticles to Increase the Antimicrobial Activity of Quercetin
Authors: Salazar Sandoval Sebastián , Bruna Tamara , Maldonado-Bravo Francisca , Bolaños Karen , Adasme-Reyes Sofía , Riveros Ana , Caro Nelson , Yutronic Nicolás , Silva Nataly , Kogan Marcelo J. , Jara Paul
Published: May 2023

This work aimed to synthesize and characterize a nanocarrier that consisted of a ternary system, namely β-cyclodextrin-based nanosponge (NS) inclusion compounds (ICs) associated with silver nanoparticles (AgNPs) to increase the antimicrobial activity of quercetin (QRC). The nanosystem was developed to overcome the therapeutical limitations of QRC. The host–guest interaction between NSs and QRC was confirmed by field emission scanning electron microscopy (FE–SEM), X-ray powder diffraction (XRPD), thermogravimetric analysis (TGA), and proton nuclear magnetic resonance (1H–NMR). Moreover, the association of AgNPs with the NS–QRC was characterized using FE–SEM, energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), dynamic light scattering (DLS), ζ-potential, and UV–Vis. Finally, the antimicrobial activity of the novel formulations was tested, which depicted that the complexation of QRC inside the supramolecular interstices of NSs increases the inhibitory effects against Escherichia coli ATCC25922, as compared to that observed in the free QRC. In addition, at the same concentrations used to generate an antibacterial effect, the NS–QRC system with AgNPs does not affect the metabolic activity of GES–1 cells. Therefore, these results suggest that the use of NSs associated with AgNPs resulted in an efficient strategy to improve the physicochemical features of QRC.
One-Dimensional Mn5Si3 Nanorods: Fabrication, Microstructure, and Magnetic Properties via a Novel Casting-Extraction Route
Authors: Li Hang , Niu Dongtao , Zhang Zhongtao , Yang Fan , Wang Hongxia , Cheng Weili
Published: May 2023

This study presents a simple and innovative approach for producing one-dimensional Mn5Si3 nanorods through a casting-extraction process. In this technique, the Mn5Si3 nanorods were synthesized by reacting Mn and Si during brass solidification and extracted by electrochemical etching of the brass matrix. The effect of the cooling rate during casting on the nanorods’ dimension, morphology, and magnetic properties was investigated. The results demonstrate that the prepared high-purity Mn5Si3 nanorods had a single-crystal D88 structure and exhibited ferromagnetism at room temperature. The morphology of the nanorods was an elongated hexagonal prism, and their preferred growth was along the [0001] crystal direction. Increasing the cooling rate from 5 K/s to 50 K/s lead to a decrease in the dimension of the nanorods but an increase in their ferromagnetism. At the optimal cooling rate of 50 K/s, the nanorods had a diameter and length range of approximately 560 nm and 2~11 μm, respectively, with a highest saturation magnetization of 7.5 emu/g, and a maximum coercivity of 120 Oe. These properties make the fabricated Mn5Si3 nanorods potentially useful for magnetic storage applications, and this study also provides a new perspective on the preparation of one-dimensional nanomaterials.
Efficient Co-Valorization of Phosphogypsum and Red Mud for Synthesis of Alkali-Activated Materials
Authors: Liu Qingsong , Xue Xiangci , Sun Zengqing , Huang Xiaoxian , Gan Min , Ji Zhiyun , Chen Xuling , Fan Xiaohui
Published: May 2023

Phosphogypsum and red mud are bulk industrial solid wastes that trigger local environmental problems. In the present investigation, an efficient valorization process was developed through which phosphogypsum and red mud can be transformed into a precursor for the synthesis of high-strength, alkali-activated materials with a seawater-bearing sodium silicate solution as the alkaline activator. The effects of the activator modulus and liquid-to-solid ratio on the strength evolution of the synthesized AAMs as well as the microstructure and chemistry of the reaction products were investigated. The results showed that mineral reconstruction between PG and RM took place during calcination at 950 °C, forming ye’elimite, anhydrite and gehlenite, which then took part in the alkali-activation process and generated thenardite and C-A-S-H gel. The mechanical properties of the synthesized AAMs, ranging from 12.9 MPa to 40.6 MPa, were determined with the activator modulus and liquid-to-solid ratio. Results from the present investigation contributed to the facile and efficient valorization of phosphogypsum and red mud into cementitious construction materials.
Basic Analytical Modeling of Creep Strain Curves
Authors: Sandström Rolf
Published: May 2023

Creep strain versus time curves (creep curves) have traditionally been described with the help of empirical models where a number of adjustable parameters are involved. These models are simple to use, but they cannot be applied for prediction. For understanding the general behavior of primary and tertiary creep, they are still useful. In fact, the phi model can represent primary creep, and the Omega model tertiary creep for a number of materials. However, in recent years, basic analytical models have been formulated that can predict and describe creep strain data without using fitting parameters. In the paper, a review of these models is given. A number of applications of the models are also given. It is demonstrated that the basic models can quantitatively predict observations. They also provide derivations of some empirical findings.
Mechanistic Study of Fast Performance Decay of PtCu Alloy-based Catalyst Layers for Polymer Electrolyte Fuel Cells through Electrochemical Impedance Spectroscopy
Authors: Grandi Maximilian , Gatalo Matija , Kamšek Ana Rebeka , Kapun Gregor , Mayer Kurt , Ruiz-Zepeda Francisco , Šala Martin , Marius Bernhard , Bele Marjan , Hodnik Nejc , Bodner Merit , Gaberšček Miran , Hacker Viktor
Published: May 2023

In the past, platinum–copper catalysts have proven to be highly active for the oxygen reduction reaction (ORR), but transferring the high activities measured in thin-film rotating disk electrodes (TF-RDEs) to high-performing membrane electrode assemblies (MEAs) has proven difficult due to stability issues during operation. High initial performance can be achieved. However, fast performance decay on a timescale of 24 h is induced by repeated voltage load steps with H2/air supplied. This performance decay is accelerated if high relative humidity (>60% RH) is set for a prolonged time and low voltages are applied during polarization. The reasons and possible solutions for this issue have been investigated by means of electrochemical impedance spectroscopy and distribution of relaxation time analysis (EIS–DRT). The affected electrochemical sub-processes have been identified by comparing the PtCu electrocatalyst with commercial Pt/C benchmark materials in homemade catalyst-coated membranes (CCMs). The proton transport resistance (Rpt) increased by a factor of ~2 compared to the benchmark materials. These results provide important insight into the challenges encountered with the de-alloyed PtCu/KB electrocatalyst during cell break-in and operation. This provides a basis for improvements in the catalysts’ design and break-in procedures for the highly attractive PtCu/KB catalyst system.
Unified Human Intention Recognition and Heuristic-Based Trajectory Generation for Haptic Teleoperation of Non-Holonomic Vehicles
Authors: Zhang Panhong , Ni Tao , Zhao Zeren , Ren Changan
Published: May 2023

In this paper, a novel bilateral shared control approach is proposed to address the issue of strong dependence on the human, and the resulting burden of manipulation, in classical haptic teleoperation systems for vehicle navigation. A Hidden Markov Model (HMM) is utilized to handle the Human Intention Recognition (HIR), according to the force input by the human—including the HMM solution, i.e., Baum–Welch algorithm, and HMM decoding, i.e., Viterbi algorithm—and the communication delay in teleoperation systems is added to generate a temporary goal. Afterwards, a heuristic and sampling method for online generation of splicing trajectory based on the goal is proposed innovatively, ensuring the vehicle can move feasibly after the change in human intention is detected. Once the trajectory is available, the vehicle velocity is then converted to joystick position information as the haptic cue of the human, which enhances the telepresence. The shared teleoperation control framework is verified in the simulation environment, where its excellent performance in the complex environment is evaluated, and its feasibility is confirmed. The experimental results show that the proposed method can achieve simple and efficient navigation in a complex environment, and can also give a certain situational awareness to the human.
Neural Network Based Control of Four-Bar Mechanism with Variable Input Velocity
Authors: Peón-Escalante R. , Flota-Bañuelos Manuel , Quintal-Palomo Roberto , Ricalde Luis J. , Peñuñuri F. , Jiménez B. Cruz , Viñas J. Avilés
Published: May 2023

For control applications, the angular velocity of the drive crank of a four-bar mechanism is traditionally assumed to be constant. In this paper, we propose control of variable velocity of the drive crank to obtain the desired output motions for the coupler point. To estimate the reference trajectory for the crank velocity, a neural network is trained with data from the kinematic model. The control law is designed from feedback linearization of the tracking error dynamics and a Proportional–Integral–Derivative (PID) controller. The applicability of the proposed scheme is validated through simulations for three variable speed profiles, obtaining excellent results from the system.
Correction: Demidova, L.A. A Novel Approach to Decision-Making on Diagnosing Oncological Diseases Using Machine Learning Classifiers Based on Datasets Combining Known and/or New Generated Features of a Different Nature. Mathematics 2023, 11, 792
Authors: Demidova Liliya A.
Published: May 2023

The author wishes to make the following corrections to this paper [...]
Stochastic Simulations of Casual Groups
Authors: Fontanari José F.
Published: May 2023

Free-forming or casual groups are groups in which individuals are in face-to-face interactions and are free to maintain or terminate contact with one another, such as clusters of people at a cocktail party, play groups in a children’s playground or shopping groups in a mall. Stochastic models of casual groups assume that group sizes are the products of natural processes by which groups acquire and lose members. The size distributions predicted by these models have been the object of controversy since their derivation in the 1960s because of the neglect of fluctuations around the mean values of random variables that characterize a collection of groups. Here, we check the validity of these mean-field approximations using an exact stochastic simulation algorithm to study the processes of the acquisition and loss of group members. In addition, we consider the situation where the appeal of a group of size i to isolates is proportional to iα. We find that, for α≤1, the mean-field approximation fits the equilibrium simulation results very well, even for a relatively small population size N. However, for α>1, this approximation scheme fails to provide a coherent description of the distribution of group sizes. We find a discontinuous phase transition at αc>1 that separates the regime where the variance of the group size does not depend on N from the regime where it grows linearly with N. In the latter regime, the system is composed of a single large group that coexists with a large number of isolates. Hence, the same underlying acquisition-and-loss process can explain the existence of small, temporary casual groups and of large, stable social groups.
Extreme Value Statistics for Evolving Random Networks
Authors: Markovich Natalia , Vaičiulis Marijus
Published: May 2023

Our objective is to survey recent results concerning the evolution of random networks and related extreme value statistics, which are a subject of interest due to numerous applications. Our survey concerns the statistical methodology but not the structure of random networks. We focus on the problems arising in evolving networks mainly due to the heavy-tailed nature of node indices. Tail and extremal indices of the node influence characteristics like in-degrees, out-degrees, PageRanks, and Max-linear models arising in the evolving random networks are discussed. Related topics like preferential and clustering attachments, community detection, stationarity and dependence of graphs, information spreading, finding the most influential leading nodes and communities, and related methods are surveyed. This survey tries to propose possible solutions to unsolved problems, like testing the stationarity and dependence of random graphs using known results obtained for random sequences. We provide a discussion of unsolved or insufficiently developed problems like the distribution of triangle and circle counts in evolving networks, or the clustering attachment and the local dependence of the modularity, the impact of node or edge deletion at each step of evolution on extreme value statistics, among many others. Considering existing techniques of community detection, we pay attention to such related topics as coloring graphs and anomaly detection by machine learning algorithms based on extreme value theory. In order to understand how one can compute tail and extremal indices on random graphs, we provide a structured and comprehensive review of their estimators obtained for random sequences. Methods to calculate the PageRank and PageRank vector are shortly presented. This survey aims to provide a better understanding of the directions in which the study of random networks has been done and how extreme value analysis developed for random sequences can be applied to random networks.
Truncated Moments for Heavy-Tailed and Related Distribution Classes
Authors: Paukštys Saulius , Šiaulys Jonas , Leipus Remigijus
Published: May 2023

Suppose that ξ+ is the positive part of a random variable defined on the probability space (Ω,F,P) with the distribution function Fξ. When the moment Eξ+p of order p>0 is finite, then the truncated moment F¯ξ,p(x)=min1,Eξp1I{ξ>x}, defined for all x⩾0, is the survival function or, in other words, the distribution tail of the distribution function Fξ,p. In this paper, we examine which regularity properties transfer from the distribution function Fξ to the distribution function Fξ,p and which properties transfer from the function Fξ,p to the function Fξ. The construction of the distribution function Fξ,p describes the truncated moment transformation of the initial distribution function Fξ. Our results show that the subclasses of heavy-tailed distributions, such as regularly varying, dominatedly varying, consistently varying and long-tailed distribution classes, are closed under this truncated moment transformation. We also show that exponential-like-tailed and generalized long-tailed distribution classes, which contain both heavy- and light-tailed distributions, are also closed under the truncated moment transformation. On the other hand, we demonstrate that regularly varying and exponential-like-tailed distribution classes also admit inverse transformation closures, i.e., from the condition that Fξ,p belongs to one of these classes, it follows that Fξ also belongs to the corresponding class. In general, the obtained results complement the known closure properties of distribution regularity classes.
Feature-Alignment-Based Cross-Platform Question Answering Expert Recommendation
Authors: Tang Bin , Gao Qinqin , Cui Xin , Peng Qinglong , Yu Xu
Published: May 2023

Community question answering (CQA), with its flexible user interaction characteristics, is gradually becoming a new knowledge-sharing platform that allows people to acquire knowledge and share experiences. The number of questions is rapidly increasing with the open registration of communities and the massive influx of users, which makes it impossible to match many questions to suitable question answering experts (noted as experts) in a timely manner. Therefore, it is of great importance to perform expert recommendation in CQA. Existing expert recommendation algorithms only use data from a single platform, which is not ideal for new CQA platforms with sparse historical interaction and a small number of questions and users. Considering that many mature CQA platforms (source platforms) have rich historical interaction data and a large amount of questions and experts, this paper will fully mine the information and transfer it to new platforms with sparse data (target platform), which can effectively alleviate the data sparsity problem. However, the feature composition of questions and experts in different platforms is inconsistent, so the data from the source platform cannot be directly transferred for training in the target platform. Therefore, this paper proposes feature-alignment-based cross-platform question answering expert recommendation (FA-CPQAER), which can align expert and question features while transferring data. First, we use the rating predictor composed by the BP network for expert recommendation within the domains, and then the feature matching of questions and experts between two domains by similarity calculation is achieved for the purpose of using the information in the source platform to assist expert recommendation in the target platform. Meanwhile, we train a stacked denoising autoencoder (SDAE) in both domains, which can map user and question features to the same dimension and align the data distributions. Extensive experiments are conducted on two real CQA datasets, Toutiao and Zhihu datasets, and the results show that compared to the other advanced expert recommendation algorithms, this paper’s method achieves better results in the evaluation metrics of MAE, RMSE, Accuracy, and Recall, which fully demonstrates the effectiveness of the method in this paper to solve the data sparsity problem in expert recommendation.
On Weak Variational Control Inequalities via Interval Analysis
Authors: Treanţă Savin , Saeed Tareq
Published: May 2023

This paper deals with the connections between the interval-valued optimal control problem and the associated weak variational control inequality. More precisely, by considering the (strictly) LU-convexity and path independence properties of the involved curvilinear integral functionals, we establish a result on the existence of LU-optimal solutions for the interval-valued optimal control problem under study, and a result on the existence of solutions for the associated weak variational control inequality.
A Novel Imputation Model for Missing Concrete Dam Monitoring Data
Authors: Cui Xinran , Gu Hao , Gu Chongshi , Cao Wenhan , Wang Jiayi
Published: May 2023

To ensure the safety of concrete dams, a large number of monitoring instruments are embedded in the bodies and foundations of the dams. However, monitoring data are often missing due to failure of monitoring equipment, human error and other factors that cause difficulties in diagnosis of dam safety and failure to precisely predict their deformation. In this paper, a new method for imputing missing deformation data is proposed. First, since the traditional deformation increment speed distance index of the deformation similarity index does not take into account the fact that there is little change in deformations occurring in two consecutive days, the denominator of the index tends to be equal to zero. In this paper, an improved index for solving this problem is proposed. A combined weighting method for calculating the deformation similarity comprehensive index and the k-means clustering method is then proposed and used to classify deformation monitoring points. Subsequently, a panel data model that imputes different types of missing data is established. The method proposed in this paper can impute missing concrete dam deformation data more accurately; therefore, it can effectively solve the missing deformation monitoring data problem.
Clinicopathological Features of Invasive Breast Cancer: A Five-Year Retrospective Study in Southern and South-Western Ethiopia
Authors: Belachew Esmael Besufikad , Desta Adey Feleke , Deneke Dinksira Bekele , Fenta Bizunesh Dires , Alem Alemwosen Teklehaymanot , Abafogi Abdo Kedir , Lukas Fekade Yerakly , Bezabih Mesele , Sewasew Dareskedar Tsehay , Kantelhardt Eva J. , Tessema Tesfaye Sisay , Howe Rawleigh
Published: May 2023

Background: Breast cancer (BC) is the most common type of cancer in Ethiopia. The incidence of BC is also rising, but the exact figure is still poorly known. Therefore, this study was conducted to address the gap in epidemiological data on BC in southern and southwestern Ethiopia. Materials and Methods: This is a five-year (2015–2019) retrospective study. The demographic and clinicopathological data were collected from biopsy reports of different kinds of breast carcinomas in the pathology department of Jimma University Specialized Hospital and Hawassa University Specialized Referral Hospital. Histopathological grades and stages were conducted using Nottingham grading and TNM staging system, respectively. Collected data were entered and analyzed using SPSS Version-20 software. Results: The mean age of patients at diagnosis was 42.27 (SD = 13.57) years. The pathological stage of most BC patients was stage III, and most of them had tumor sizes greater than 5 cm. Most patients had moderately differentiated tumor grade, and mastectomy was the most common type of surgery at the time of diagnosis. Invasive ductal carcinoma was the most common histological type of BC, followed by invasive lobular carcinoma. Lymph node involvement was seen in 60.5% of cases. Lymph node involvement was associated with tumor size (χ2 = 8.55, p = 0.033) and type of surgery (χ2 = 39.69, p < 0.001). Conclusions: This study showed that BC patients in southern and southwestern Ethiopia displayed advanced pathological stages, relatively young age at diagnosis, and predominant invasive ductal carcinoma histological patterns.
Powder Metallurgy Fabrication and Characterization of Ti6Al4V/xCu Alloys for Biomedical Applications
Authors: Vergara-Hernández Hector Javier , Olmos Luis , Solorio Victor Manuel , Bouvard Didier , Villalobos-Brito Julio , Chávez Jorge , Jimenez Omar
Published: May 2023

Ti6Al4V (Ti64) alloy is the most used metal material for bone implants because of its good biocompatibility and adapted mechanical properties. Nevertheless, it shows low antibacterial activity, which may favor its failure. Addition of antibacterial elements such as copper should avoid this drawback. This work studies the addition of Cu into a Ti64 matrix resulting in Ti64/xCu composites. Powder mixtures of Ti64/xCu were compacted in a die and then sintered at 1100 °C. Sintering kinetics indicate that densification is achieved by pore filling due to eutectic liquid formed by the reaction of Ti and Cu. The microstructure of the sintered samples is composed mainly of α-Ti and Ti2Cu phases, but TixCuy intermetallics were also found. Microhardness is increased by the addition of Cu due to densification and the formation of harder phases such as Ti2Cu. However, the stiffness and compression strength are barely the same for all composites. The corrosion resistance is significantly improved by the addition of Cu. Finally, the material with 15 wt% of copper showed the best compromise.
Investigation of the LME Susceptibility of Dual Phase Steel with Different Zinc Coatings
Authors: El-Sari Bassel , Biegler Max , Rethmeier Michael
Published: May 2023

The application of anti-corrosion coated, high-strength steels in the automotive industry has increased in recent years. In combination with various zinc-based surface coatings, liquid metal embrittlement cracking can be observed in some of these materials. A high-quality, crack-free spot-welded joint is essential to realize the lightweight potential of the materials. In this work, the LME susceptibility of different coatings, which will be determined by the crack length and the occurrence rate, will be investigated using a welding under external load setup. The uncoated specimens did not show any LME. EG, GI and GA showed significantly less LME than ZM coatings. The latter coatings showed much larger crack lengths than the EG, GI and GA coatings. Furthermore, two mechanisms regarding the LME occurrence rate were observed: the occurrence of LME in zinc–magnesium coatings was theorized to be driven by the material properties of the coatings, whereas the occurrence of LME at EG, GI and GA samples was forced mainly by the application of the external tensile load. In the experimental setup of this work, the materials were exposed to unusually high mechanical loads (up to 80% of their yield strength) to evoke LME cracks.
Re-Synthesis of CIGS Nanocrystallites Using Oxidation Roasting Pretreatment from Spent CIGS Targets
Authors: Hsiang Hsing-I , Chen Chih-Cheng , Chiang Chung-Yen
Published: May 2023

The CIGS (Cu(In, Ga)Se2) thin film solar cell sputtering process utilizes only 30% of the original target. The remaining 70% of the target must be recycled to achieve In, Ga, and Se rare metal sustainable use. It is, therefore, very important to establish spent CIGS target recycling technology to reduce environmental damage. CIGS is a tetrahedrally bonded semiconductor with a chalcopyrite crystal structure. Chalcopyrite is resistant to attack by the oxidants used in dissolution due to forming a passivation surface layer. Therefore, increasing the reaction temperature, lixiviating agent, and oxidant concentrations is necessary to enhance CIGS dissolution. The oxidation roasting pretreatment effects on the recovery and leaching of spent CIGS targets are investigated in this study. The results indicated that the proper oxidation roasting pretreatment process could significantly enhance CIGS leaching, reducing costs and increasing the reaction rate. This can be explained by the fact that the chalcopyrite structure was decomposed and transformed into easier dissolvable Cu2SeO4, In2O3, and amorphous Ga2O3 after roasting in the air. Cu, In, and Ga recoveries can reach above 99.9% by leaching CIGS roasted at 500 °C in 1 M H2SO4 at 60 °C for 1 h. As the roasting temperature was increased to 600 °C, the Ga recovery rate decreased due to the formation of difficult dissolvable β-Ga2O3. Mono-dispersed, near-stoichiometric CIGS nanoparticles with a mean crystallite size of 9 nm can be obtained using a direct recycling process combining oxidation, leaching, and re-synthesis processes.
Anti-Allergic Effect of Dietary Polyphenols Curcumin and Epigallocatechin Gallate via Anti-Degranulation in IgE/Antigen-Stimulated Mast Cell Model: A Lipidomics Perspective
Authors: Zeng Jun , Hao Jingwen , Yang Zhiqiang , Ma Chunyu , Gao Longhua , Chen Yue , Li Guiling , Li Jia
Published: May 2023

Polyphenol-rich foods exhibit anti-allergic/-inflammatory properties. As major effector cells of allergies, mast cells undergo degranulation after activation and then initiate inflammatory responses. Key immune phenomena could be regulated by the production and metabolism of lipid mediators by mast cells. Here, we analyzed the antiallergic activities of two representative dietary polyphenols, curcumin and epigallocatechin gallate (EGCG), and traced their effects on cellular lipidome rewiring in the progression of degranulation. Both curcumin and EGCG significantly inhibited degranulation as they suppressed the release of β-hexosaminidase, interleukin-4, and tumor necrosis factor-α from the IgE/antigen-stimulated mast cell model. A comprehensive lipidomics study involving 957 identified lipid species revealed that although the lipidome remodeling patterns (lipid response and composition) of curcumin intervention were considerably similar to those of EGCG, lipid metabolism was more potently disturbed by curcumin. Seventy-eight percent of significant differential lipids upon IgE/antigen stimulation could be regulated by curcumin/EGCG. LPC-O 22:0 was defined as a potential biomarker for its sensitivity to IgE/antigen stimulation and curcumin/EGCG intervention. The key changes in diacylglycerols, fatty acids, and bismonoacylglycerophosphates provided clues that cell signaling disturbances could be associated with curcumin/EGCG intervention. Our work supplies a novel perspective for understanding curcumin/EGCG involvement in antianaphylaxis and helps guide future attempts to use dietary polyphenols.
Si Photonics FMCW LiDAR Chip with Solid-State Beam Steering by Interleaved Coaxial Optical Phased Array
Authors: Lei Yufang , Zhang Lingxuan , Yu Zhiyuan , Xue Yulong , Ren Yangming , Sun Xiaochen
Published: May 2023

LiDAR has attracted increasing attention because of its strong anti-interference ability and high resolution. Traditional LiDAR systems rely on discrete components and face the challenges of high cost, large volume, and complex construction. Photonic integration technology can solve these problems and achieve high integration, compact dimension, and low-cost on-chip LiDAR solutions. A solid-state frequency-modulated continuous-wave LiDAR based on a silicon photonic chip is proposed and demonstrated. Two sets of optical phased array antennas are integrated on an optical chip to form a transmitter–receiver interleaved coaxial all-solid-state coherent optical system which provides high power efficiency, in principle, compared with a coaxial optical system using a 2 × 2 beam splitter. The solid-state scanning on the chip is realized by optical phased array without a mechanical structure. A 32-channel transmitter–receiver interleaved coaxial all-solid-state FMCW LiDAR chip design is demonstrated. The measured beam width is 0.4° × 0.8°, and the grating lobe suppression ratio is 6 dB. Preliminary FMCW ranging of multiple targets scanned by OPA was performed. The photonic integrated chip is fabricated on a CMOS-compatible silicon photonics platform, providing a steady path to the commercialization of low-cost on-chip solid-state FMCW LiDAR.
Impacts of Temperature and Water Activity Interactions on Growth, Aflatoxin B1 Production and Expression of Major Biosynthetic Genes of AFB1 in Aspergillus flavus Isolates
Authors: Al-Zaban Mayasar I.
Published: May 2023

The contamination of peanuts, with Aspergillus flavus and subsequent aflatoxins (AFs) is considered to be one of the most serious, safety problems in the world. Water activity (aw) and temperature are limiting, factors for fungal growth and aflatoxin production during storage. The objectives of this study were to integrate data on the effects of temperature (34, 37, and 42 °C) and water activity (aw; 0.85, 0.90, and 0.95) on growth rate aflatoxin B1 (AFB1) production and up- or-downregulation of the molecular expression of biosynthetic AFB1 genes divided into three types based on their A. flavus isolate composition and AFB1 capacity in vitro: A. flavus KSU114 (high producer), A. flavus KSU114 (low producer), and A. flavus KSU121 (non-producer). The A. flavus isolates were shown to be resilient in terms of growth on yeast extract sucrose agar media when exposed to temperature and water activity as pivotal environmental factors. The optimal conditions for the fungal growth of three isolates were a temperature of 34 °C and water activity of 0.95 aw; there was very slow fungal growth at the highest temperature of 42 °C, with different aw values causing inhibited fungal growth. The AFB1 production for the three isolates followed the same pattern with one exception: A. flavus KSU114 failed to produce any AFB1 at 42 °C with different aw values. All tested genes of A. flavus were significantly up- or downregulated under three levels of interaction between temperature and aw. The late structural genes of the pathway were significantly upregulated at 34 °C under aw 0.95, although aflR, aflS and most of the early structural genes were upregulated. Compared to 34 °C with an aw value of 0.95, most of the expressed genes were significantly downregulated at 37 and 42 °C with aw values of 0.85 and 0.90. Additionally, two regulatory genes were downregulated under the same conditions. The expression level of laeA was also completely associated with AFB1 production, while the expression level of brlA was linked to A. flavus colonization. This information is required to forecast the actual effects of climate change on A. flavus. The findings can be applied to improve specific food technology processes and create prevention strategies to limit the concentrations of potential carcinogenic substances in peanuts and their derivatives.
Relative Abundance and Detection of Pseudomonas aeruginosa from Chronic Wound Infections Globally
Authors: Phan Sang , Feng Cafrey He , Huang Raymond , Lee Zeng X. , Moua Yer , Phung Olivia J. , Lenhard Justin R.
Published: May 2023

Pseudomonas aeruginosa is a difficult-to-treat pathogen that is frequently involved with chronic wound infections. Here, we conducted a literature search of world-wide studies published between 2005 and 2022 that described the microbiological profiles of chronic wound infections. For each continent, a hierarchy of pathogens was created to define the organisms that were most frequently isolated in each region. Except for South America, P. aeruginosa was the second most common organism in each major continent, with Staphylococcus aureus being the most abundant pathogen overall. When individual countries were evaluated, P. aeruginosa was the most frequently isolated organism in several Southeast Asia nations including India and Malaysia. P. aeruginosa was less commonly isolated from diabetic foot infections in North America, Europe, and Africa in comparison to other types of chronic wound infections. Additionally, the Levine wound swab technique may be a quick and painless way to isolate P. aeruginosa from wound infections, but the isolation of P. aeruginosa does not seem to be an informative predictor of the patient’s clinical course. A multivariate risk assessment that accounts for the regional frequency of P. aeruginosa isolation may be an appropriate way to guide empiric management of chronic wound infections.