bluuebunny/crossref_metadata_2025 huggingface dataset:
Can Entrepreneurs Who Experienced Business Closure Bring Their New Start-Up to a Successful M&A?
Authors: Harel Shai , Solodoha Eliran , Rosenzweig Stav
Published: August 2022

Numerous technology start-ups end up shutting down their operations. The present study aims to answer the following research questions: can entrepreneurs who closed their previous ventures bring their new venture to a successful exit through M&A and to what extent does this positive outcome correspond to whether investors funded their start-up? We examine 9723 technology start-ups established by 19,458 entrepreneurs. About half of the start-ups were funded, and 3463 of them had entrepreneurs with closure or with M&A experience. We find that entrepreneurs with closure experience are negatively associated with the probability of M&A as a main effect, in line with the theory that indicates imprinting. Nevertheless, entrepreneurs with closure experience are positively associated with the probability of M&A when their co-founders have M&A experience. We suggest that entrepreneurs with closure experience can compensate for their lack of M&A experience by learning from their peers who possess this experience. We discuss implications for theory, investors, and entrepreneurs.
A Study of Resident Satisfaction and Factors That Influence Old Community Renewal Based on Community Governance in Hangzhou: An Empirical Analysis
Authors: Gao Hui , Wang Ting , Gu Shifeng
Published: August 2022

In recent years, most Chinese cities have been implementing renewal projects to improve the quality of life in old communities. “How” and “what” to renew has attracted much attention from the government and scholars. “What to renew” is closely related to the needs of a city’s population and should be determined by residents, while renewal effects are influenced by government action and the multiple parties that participate in a renewal project. Resident satisfaction should be used as the key indicator to measure the effects of renewal. Therefore, it is necessary to analyze resident satisfaction with the renewal of an old community and explore the factors that affect satisfaction. To address this question, we utilize an index system to measure resident satisfaction with community renewal on the basis of community governance and explore the impact of community governance on resident satisfaction by constructing an ordinal logistic regression model, based on the data collected in 19 communities in the city of Hangzhou, China. The regression results are analyzed, and corresponding countermeasures are proposed.
Geotrails as a Medium for Education and Geotourism: Recommendations for Quality Improvement Based on the Results of a Research Project in the Swabian Alb UNESCO Global Geopark
Authors: Stolz Julian , Megerle Heidi Elisabeth
Published: August 2022

Geotourism is one of the fastest growing tourism branches. Geoparks feature prominently in geotourism as well as geoeducation. Well-designed geotrails link local geology, geoheritage and geoeducation. Unfortunately many trails do not consider or insufficiently acknowledge recent didactic and touristic findings. As a result, they fail to interest a lay audience in geological phenomena, convey relevant information, and attract tourists to the region. A catalogue of state-of-the-art criteria for the evaluation of existing geotrails based on a case study of the UNESCO Global Geopark Swabian Alb (Germany) was elaborated by a comprehensive literature research and subsequently verified on the basis of selected model trails. Finally, recommendations for model geotrails were derived. The term “model” refers in this case to aspects of geoeducation as well as geotourism. Results showed considerable enhancements, but also the further necessity of improvements such as a stronger consideration of Education for sustainable Development (ESD), a better integration of the criteria of geo-interpretation as well as the opportunities and potentials offered by the to-date too scarcely used new technologies. Our surveys in the UGGp Swabian Alb largely coincide with the results of national and international research. Often it is merely small factors that differentiate an adequate and a model geotrail. Our checklist of criteria offers a good basis for these factors.
Land Management and Rural Development in Northwest China
Authors: Ma Libang , Li Yawei , Cui Xijuan , Tao Tianmin
Published: August 2022

In order to break away from the overreliance on a single industry and the simple supply of agricultural products, rural multifunctional research has gradually received public attention. To a certain extent, multifunctional classification governance paths can enhance rural competitiveness and land use efficiency and alleviate the problems of local poverty and unbalanced development in rural regions. Based on the theory of rural multifunctionality, this paper reveals the spatial characteristics and coordination of rural multifunctionality at the township scale, analyzes the barrier functions of different regions, and clarifies the direction of rural development using the rural assessment method, the trade-off synergy model, and the dysfunctional diagnostic model, taking Yongchang County in the western corridor of China as an example. On this basis, we further discuss the path selection of rural governance in northwest China. The results show that: (1) The spatial distribution of rural functions has pronounced heterogeneity, with better life security functions and ecological background functions, and similar spatial patterns; economic development functions are on the low side, showing the divergent characteristics of enhancement from the township center to the surrounding area. The functions of agricultural production are low, and the spatial distribution is similar to that for the living guarantee function. (2) The living guarantee function has a strong trade-off effect on the ecological background function, and the living guarantee and ecological background functions have a synergistic effect on the agricultural development function. (3) We classified types of villages according to the intensity index of village function trade-offs and clarified the functional development characteristics of each administrative village. The incompatibility of village functions caused by different demands is the root hinderance to the development of villages.
Production–Living–Ecological Risk Assessment and Corresponding Strategies in China’s Provinces under Climate Change Scenario
Authors: Hou Wenjuan , Wu Shaohong , Yang Linsheng , Yin Yunhe , Gao Jiangbo , Deng Haoyu , Wu Maowei , Li Xiaojie , Liu Lulu
Published: August 2022

In the context of the increasing frequency of natural disasters caused by climate change in recent years, rational territorial spatial planning must pay attention to production–living–ecological (PLE) risks under climate change scenarios. In this study, a method synthesizing the Box–Cox transformation and area weighted averaging is established for characterizing the PLE risks in China’s provinces, which are divided into three zones to cope with PLE risks. Further, targeted strategies from the perspective of the disaster-induced factors and disaster-affected objects are explored for the regions within the different zones. The results show that the regions with a high production risk are mainly distributed in Guangdong, Henan, and Shandong, with an index between 0.80 and 1.00; the regions with a high living risk are concentrated in Jiangsu, Anhui, Guangdong, and Hainan, with an index exceeding 0.72; and the regions with a high ecological risk are concentrated in Guangxi, Ningxia, and Yunnan, with an index exceeding 0.50. The overall PLE risk is high along the southeastern coast, intermediate in central and western China, and low on the Tibetan Plateau. From the A to C zones, the number of risk types and intensity of risks requiring attention gradually decrease. For the category A zone, recommended measures include the construction of disaster risk monitoring and early warning systems for coastal cities and major grain-producing regions, the development of urban ecological protection zones, and the adjustment of economic and energy structures, etc. Production and living risks are central to the category B zone, while ecological and production risks are central to the category C zone. This study can provide theoretical support for China’s scientific development of land planning and the realization of a beautiful China.
Acid Number Prediction Model of Lubricating Oil Based on Mid-Infrared Spectroscopy
Authors: Zhou Fanhao , Yang Kun , Li Dayang , Shi Xinfa
Published: August 2022

The monitoring and replacement of lubricating oil has an important impact on mechanical equipment. In this study, based on the infrared spectroscopy monitoring method, an acid value index prediction model is established. The support vector machine regression method is used to quantitatively analyze the acid number of the oil sample, which verifies the stability and predictive ability of the quantitative prediction model, and we provide a theoretical basis and practical examples for the online monitoring of oil indicators. In addition, a support vector machine regression model is established by observing the changing law of the spectral absorption peak and selecting the dominant wavelength, and it is compared against the prediction algorithm of the long- and short-term memory network. By comparing the deviation relationship between the predicted value and the real chemical value, the feasibility of the infrared spectroscopy prediction model is verified. The experimental results show that the correlation coefficient between the predicted value of the model and the actual measured value reaches 0.98. This proves that the prediction effect of the prediction model based on the infrared spectrum data and the support vector machine regression method is better than that of the long- and short-term memory network trend prediction model, and the predicted results are reliable.
Research on Pneumatic–liquid On-Line Automatic Balance Technology for High-End Turbine Units
Authors: Pan Xin , Ge Dehong , Li Wei , Huo Jiaji
Published: August 2022

Rotor mass imbalance is the main cause of vibration overload of high-end turbine units, which can easily induce a variety of failures such as shaft tile and seal wear, and blade breakage. The online automatic balancing system can solve the problem of imbalance of rotor mass during the operation of the equipment, and at the same time can ensure the long-term stable operation of the equipment. Therefore, a new pneumatic–liquid on-line automatic balance (PLOABS) system is proposed for high-end turbine units, which has the advantages of simple structure, no moving parts in the rotating element, closed action environment, reversible balancing process and can maintain the original state when restarted. Using ANSYS software, the gas driving force and the internal gas–liquid rotating flow field of the actuator are simulated and analyzed, and the actuator structure has been further optimized. At the same time, a set of the PLOABS system is built to conduct automatic balancing experiments. The results showed that the rotor amplitude was reduced from 18.3 to 10.6 μm, which verified the feasibility and effectiveness of the PLOABS technology and laid the foundation for the subsequent engineering application of the PLOABS technology.
Assessment of Industry 4.0 for Modern Manufacturing Ecosystem: A Systematic Survey of Surveys
Authors: Konstantinidis Fotios K. , Myrillas Nikolaos , Mouroutsos Spyridon G. , Koulouriotis Dimitrios , Gasteratos Antonios
Published: August 2022

The rise of the fourth industrial revolution aspires to digitize any traditional manufacturing process, paving the way for new organisation schemes and management principles that affect business models, the environment, and services across the entire value chain. During the last two decades, the generated advancements have been analysed and discussed from a bunch of technological and business perspectives gleaned from a variety of academic journals. With the aim to identify the digital footprint of Industry 4.0 in the current manufacturing ecosystem, a systematic literature survey of surveys is conducted here, based on survey academic articles that cover the current state-of-the-art. The 59 selected high-impact survey manuscripts are analysed using PRISMA principles and categorized according to their technologies under analysis and impact, providing valuable insights for the research and business community. Specifically, the influence Industry 4.0 exerts on traditional business models, small and medium-sized enterprises, decision-making processes, human–machine interaction, and circularity affairs are investigated and brought out, while research gaps, business opportunities, and their relevance to Industry 5.0 principles are pointed out.
Friction-Induced Efficiency Losses and Wear Evolution in Hypoid Gears
Authors: Grabovic Eugeniu , Artoni Alessio , Gabiccini Marco , Guiggiani Massimo , Mattei Lorenza , Di Puccio Francesca , Ciulli Enrico
Published: August 2022

A correct methodology to evaluate the friction coefficient in lubricated gear pairs is paramount for both the estimation of energy losses and the prediction of wear. In the first part of the paper, a methodology for estimating the coefficient of friction with a semi-empirical formulation is presented, and its results are also employed to analyze mechanical efficiency losses in a hypoid gearset. Hypoid gears have complex tooth surface geometries, and the entraining kinematics of the lubricant is quite involved. The second part of the paper showcases a simulated wear investigation based on the Archard model. The main focus is on the impact of the frequency adopted for updating the worn geometry of the gear and pinion teeth on the fidelity and consistency of the tribological outcomes. These are measured in terms of overall quantity of material removed and characteristics of the loaded contact pattern. More in detail, a sensitivity analysis is presented that compares the total wear of a hypoid gearset after 30 million cycles estimated using different geometry update steps. Contact pressures, which are necessary to perform the aforementioned analyses, are calculated through an accurate, state-of-the-art loaded tooth contact analysis solver.
Optimized Deep-Learning-Based Method for Cattle Udder Traits Classification
Authors: Afridi Hina , Ullah Mohib , Nordbø Øyvind , Cheikh Faouzi Alaya , Larsgard Anne Guro
Published: August 2022

We propose optimized deep learning (DL) models for automatic analysis of udder conformation traits of cattle. One of the traits is represented by supernumerary teats that is in excess of the normal number of teats. Supernumerary teats are the most common congenital heritable in cattle. Therefore, the major advantage of our proposed method is its capability to automatically select the relevant images and thereafter perform supernumerary teat classification when limited data are available. For this purpose, we perform experimental analysis on the image dataset that we collected using a handheld device consisting of a combined depth and RGB camera. To disclose the underlying characteristics of our data, we consider the uniform manifold approximation and projection (UMAP) technique. Furthermore, for comprehensive evaluation, we explore the impact of different data augmentation techniques on the performances of DL models. We also explore the impact of only RGB data and the combination of RGB and depth data on the performances of the DL models. For this purpose, we integrate the three channels of RGB data with the depth channel to generate four channels of data. We present the results of all the models in terms of four performance metrics, namely accuracy, F-score, precision, and sensitivity. The experimental results reveal that a higher level of data augmentation techniques improves the performances of the DL models by approximately 10%. Our proposed method also outperforms the reference methods recently introduced in the literature.
Optimal Harvesting of Stochastically Fluctuating Populations Driven by a Generalized Logistic SDE Growth Model
Authors: Brites Nuno M.
Published: August 2022

We describe the growth dynamics of a stock using stochastic differential equations with a generalized logistic growth model which encompasses several well-known growth functions as special cases. For each model, we compute the optimal variable effort policy and compare the expected net present value of the total profit earned by the harvester among policies. In addition, we further extend the study to include parameters sensitivity, such as the costs and volatility, and present an explicitly Crank–Nicolson discretization scheme necessary to obtain optimal policies.
Electric-Vehicle Routing Planning Based on the Law of Electric Energy Consumption
Authors: Ding Nan , Yang Jingshuai , Han Zhibin , Hao Jianming
Published: August 2022

In this paper, we establish the Electric Vehicle Routing Problem with Time Windows Based on Driving Cycles (EVRPTW-DC) to optimize the delivery routing of electric vehicles (EVs). As energy consumption may affect the maximal driving range and the recharging behavior of EVs, we first develop a nonlinear electric energy consumption model based on typical driving cycles of suburban and urban areas, with consideration of vehicle load, travel distance, and speed. An adaptive particle swarm optimization algorithm is then designed to solve the problem. Moreover, we study cases built from the actual operational data of Company J and compare the optimal delivery schemes of EVRPTW-DC and EVRPTW under the traditional linear electric energy consumption law. The results show that our nonlinear energy consumption model, which provides a better simulation of energy consumption, can lead to a more realistic delivery plan. Finally, we explore the applicability of the proposed EVPRTW-DC and discuss the conditions of using a linear electric energy consumption coefficient.
A Target Damage Assessment Mathematical Model and Calculation Method Based on the Intersection of Warhead Fragment and Target Mechanism
Authors: Zhang Xiaoqian , Li Hanshan
Published: August 2022

This paper proposes a target damage calculation method based on the profit-loss value of a warhead fragment group. The group is discretized into a fan-shaped column warhead fragment dispersion arrangement model, and the angle of its intersection with the target is combined to establish the dynamic dispersion density model of the warhead fragment group. In addition, the function to calculate the number of warhead fragments hitting the target’s surface is devised. The capability matrix of the warhead fragment group is constructed according to the quality, quantity, and storage velocity of the warhead fragments, and then, the profit-loss value of the warhead fragment group is established. Combining the intersection probability of the target and the warhead fragment of the dispersion area, the model to calculate the probability of damage caused to the target by the warhead fragment group formation is deduced. The calculation and experimental analysis verifies that the dispersion angle of warhead fragments, the intersection angle of projectile and target, and the intersection distance of projectile and target significantly influence the impact of target damage.
A Comprehensive Optimization Model of Tooth Surface Parameters for the Minimization of Contact Stress of Helical Face Gears by Considering the Avoidance of Edge Contact
Authors: Wang Shenghui , Hu Bo , Wu Zhenyu , Zhou Yuansheng , Tang Jinyuan
Published: August 2022

Optimization with edge contact avoidance and contact stress minimization is essential for gear design. Due to the complex geometry of modified helical face gear drives, it is complicated to find the optimal design parameters with the consideration of issues including loading, assembly errors, and edge contact. As the finite element method is tedious and time-consuming, an optimization model with a simplified algorithm of the loaded tooth contact analysis with errors (ELTCA) for modified helical face gears is presented, and it can programmatically optimize the contact stress with edge contact avoidance. Firstly, a simplified ETCA algorithm is introduced, which reduces the five unknowns in the traditional contact equations to three. Secondly, the LTCA is analytically implemented according to the Hertz theory. Subsequently, an optimization model with the objective function of avoiding edge contact and reducing maximum contact stress is proposed. Furthermore, the proposed model is applied to reveal the effects of design parameters and assembly errors on the optimized contact path and stress. The results show that the optimization model is accurate and efficient; the design parameters and assembly errors have great effects on the meshing of modified helical face gears.
Quantum Tree Search with Qiskit
Authors: Wichert Andreas
Published: August 2022

We indicate the quantum tree search qiskit implementation by popular examples from symbolical artificial intelligence, the 3-puzzle, 8-puzzle and the ABC blocks world. Qiskit is an open-source software development kit (SDK) for working with quantum computers at the level of circuits and algorithms from IBM. The objects are represented by symbols and adjectives. Two principles are presented. Either the position description (adjective) is fixed and the class descriptors moves (is changed) or, in the reverse interpretation, the class descriptor is fixed and the position descriptor (adjective) moves (is changed). We indicate how to decompose the permutation operator that executes the rules by the two principles. We demonstrate that the the branching factor is reduced by Grover’s amplification to the square root of the average branching factor and not to the maximal branching factor as previously assumed.
Bounds for Incomplete Confluent Fox–Wright Generalized Hypergeometric Functions
Authors: Pogány Tibor K.
Published: August 2022

We establish several new functional bounds and uniform bounds (with respect to the variable) for the lower incomplete generalized Fox–Wright functions by means of the representation formulae for the McKay Iν Bessel probability distribution’s cumulative distribution function. New cumulative distribution functions are generated and expressed in terms of lower incomplete Fox–Wright functions and/or generalized hypergeometric functions, whilst in the closing part of the article, related bounding inequalities are obtained for them.
Fast Image Restoration Method Based on the L0, L1, and L2 Gradient Minimization
Authors: Wang Jin , Xia Qing , Xia Binhu
Published: August 2022

In this paper, we propose a novel image denoising method by coupling with L0, L1 and L2 gradient minimization. Our proposed method smoothes the gradient difference between image pixels and noise pixels and sharpens the edges by increasing the steepness of transition. We focus on global noise processing rather than local features and adaptively process noise signals with different characteristics. Based on the half-quadratic splitting method, we perform a smoothing step realized by a Poisson approach and two edge-preserving steps through an optimization formulation. This iterative method is fast, simple, and easy to implement. The proposed numerical scheme can be performed to a discrete cosine transform implementation, which can be applied with parallel GPUs computing in a straightforward manner. Various tests are presented, including both qualitative and quantitative tests, to demonstrate that the proposed method is efficient and robust for producing image processing results with good quality.
The Use of Biocompatible Membranes in Oral Surgery: The Past, Present & Future Directions. A Narrative Review
Authors: Kormas Ioannis , Pedercini Alessandro , Alassy Hatem , Wolff Larry F.
Published: August 2022

The use of biocompatible membranes in periodontal and oral surgery is an important part of regeneration. Over the years, several different membranes have been developed, ranging from non-resorbable membranes that have to be removed in a separate procedure, to collagen membranes that completely resorb on their own, thus avoiding the need for a second surgery. Autogenous membranes are becoming increasingly popular in more recent years. These membranes can be used with a great variety of techniques in the four main hard tissue regenerative procedures: guided tissue regeneration, alveolar ridge preservation, guided bone regeneration and sinus floor augmentation. A review of the literature was conducted in order to identify the most commonly used membranes in clinical practice, as well as the most promising ones for regeneration procedures in the future. The information provided in this review may serve as a guide to clinicians, in order to select the most applicable membrane for the clinical case treated as the correct choice of materials may be critical in the procedure’s success.
Membrane Fouling Diagnosis of Membrane Components Based on MOJS-ADBN
Authors: Shi Yaoke , Wang Zhiwen , Du Xianjun , Gong Bin , Lu Yanrong , Li Long , Ling Guobi
Published: August 2022

Given the strong nonlinearity and large time-varying characteristics of membrane component fouling in the membrane water treatment process, a membrane component-membrane fouling diagnosis method based on the multi-objective jellyfish search adaptive deep belief network (MOJS-ADBN) is proposed. Firstly, the adaptive learning rate is introduced into the unsupervised pre-training phase of DBN to improve the convergence speed of the network. Secondly, the MOJS method is used to replace the gradient-based layer-by-layer weight fine-tuning method in traditional DBN to improve the ability of network feature extraction. At the same time, the convergence of the MOJS-ADBN learning process is proven by constructing the Lyapunov function. Finally, MOJS-ADBN is used in the membrane packaging diagnosis to verify the performance of the model diagnosis. The experimental results show that MOJS-ADBN has a fast convergence speed and a high diagnostic accuracy, and can provide a theoretical basis for membrane fouling diagnosis in the actual operation of membrane water treatment.
Applications of Molecular Dynamics Simulation in Protein Study
Authors: Sinha Siddharth , Tam Benjamin , Wang San Ming
Published: August 2022

Molecular Dynamics (MD) Simulations is increasingly used as a powerful tool to study protein structure-related questions. Starting from the early simulation study on the photoisomerization in rhodopsin in 1976, MD Simulations has been used to study protein function, protein stability, protein–protein interaction, enzymatic reactions and drug–protein interactions, and membrane proteins. In this review, we provide a brief review for the history of MD Simulations application and the current status of MD Simulations applications in protein studies.
Disulfiram Oxy-Derivatives Suppress Protein Retrotranslocation across the ER Membrane to the Cytosol and Initiate Paraptosis-like Cell Death
Authors: Solovieva Marina , Shatalin Yuri , Odinokova Irina , Krestinina Olga , Baburina Yulia , Lomovskaya Yana , Pankratov Anton , Pankratova Natalia , Buneeva Olga , Kopylov Arthur , Medvedev Alexei , Akatov Vladimir
Published: August 2022

Disulfiram (DSF) and its derivatives were here investigated as antineoplastic agents, and their important feature is the ability to influence the UPS. We have recently shown that hydroxocobalamin catalyzes the aerobic oxidation of diethyldithiocarbamate to form disulfiram and its oxy-derivatives (DSFoxy; i.e., sulfones and sulfoxides), which induce cytoplasm vacuolization and paraptosis-like cancer cell death. We used LC-MS/MS and bioinformatics analysis to determine the key points in these processes. DSFoxy was found to induce an increase in the number of ubiquitinated proteins, including oxidized ones, and a decrease in the monomeric ubiquitin. Enhanced ubiquitination was revealed for proteins involved in the response to exogenous stress, regulation of apoptosis, autophagy, DNA damage/repair, transcription and translation, folding and ubiquitination, retrograde transport, the MAPK cascade, and some other functions. The results obtained indicate that DSF oxy-derivatives enhance the oxidation and ubiquitination of many proteins regulating proteostasis (including E3 ligases and deubiquitinases), which leads to inhibition of protein retrotranslocation across the ER membrane into the cytosol and accumulation of misfolded proteins in the ER followed by ER swelling and initiates paraptosis-like cell death. Our results provide new insight into the role of protein ubiquitination/deubiquitination in regulating protein retrotranslocation across the ER membrane into the cytosol and paraptosis-like cell death.
Wear and Corrosion Resistance of FeCoCrxNiAl High-Entropy Alloy Coatings Fabricated by Laser Cladding on Q345 Welded Joint
Authors: Ben Qiang , Zhang Yumeng , Sun Longxiang , Wang Leilei , Wang Yanni , Zhan Xiaohong
Published: August 2022

High-entropy alloy (HEA) coatings on the surface of low-alloy steel by laser cladding can improve the corrosion and wear resistance, and the performance can be further improved by adding the Cr element. However, the effect of Cr content on the microstructure, hardness, wear and corrosion resistance of the coatings on the welded joint has not been completely understood in the literature. This paper aims at revealing the influence of Cr content on the microstructure and properties of laser-cladded FeCoCrxNiAl HEA on different regions of Q345 welded structure. The results indicate that FeCoCrxNiAl HEA coating has good metallurgical bonding with the Q345 welded surface. The increase of Cr element content in the powder plays an important role in energy absorption of powder and substrate, affecting the dilution rate and diffusion of Fe from the substrate to HEA coating. The HEA coating is mainly composed of the face-centered cubic phase (FCC) and body-centered cubic phase (BCC). When x = 1.5, the actual Cr element content of coating is the highest, which promotes the formation of hard brittle phase BCC, and subsequently affects the hardness and wear resistance of the sample. Meanwhile, the corrosion resistance increases and then decreases, and reaches the highest when x = 1.5. Due to the existence of Cr and other elements with good corrosion resistance in the HEA coating, a dense oxide film can be formed in 3.5 wt.% NaCl solution and neutral salt spray environment to prevent the corrosion from continuing, which can effectively improve the corrosion resistance of each region of the welded joint, and the protective efficiencies on the weld bead (WB), heat-affected zone (HAZ) and base metal (BM) are 99.1, 98.4 and 96.6%, respectively.
Strain-Rate Effect on Anisotropic Deformation Characterization and Material Modeling of High-Strength Aluminum Alloy Sheet
Authors: Zhang Feifei , He Kai , Li Zheng , Huang Bo
Published: August 2022

Aluminum alloy sheets are widely applied as structure components in automotive, aircraft and other industries to realize lightweight. Nowadays, many high strain rate forming techniques have been developed to improve their formability and widen their application. To ensure the reliability of the aluminum alloy structure components under high strain rate conditions, it is imperative to develop a thorough understanding of the alloy’s mechanical properties. In this paper, taking high-strength 6XXX aluminum alloy sheet as an example, the anisotropic deformation characterization and corresponding material models at various strain-rate conditions are investigated systematically. The material hardening curves and anisotropic plastic yielding stresses were achieved based on the quasi-static uniaxial tensile test and the split Hopkinson tensile bar tests. In this study, the Johnson–Cook hardening model and two anisotropic yield functions are applied to well describe the strain-rate-dependent anisotropic plastic deformation behavior. In addition, the fractographic characterization of the fractured samples at various strain-rate conditions are measured and compared. The study systematically investigates the influence of strain rate on the anisotropic deformation behavior of the high-strength aluminum alloy sheets and gives the basic experimental data for their application in engineering fields in the future.
Activation Behavior of {10-12}-{10-12} Secondary Twins by Different Strain Variables and Different Loading Directions during Fatigue Deformation of AZ31 Magnesium Alloy
Authors: Tan Li , Huang Xingyu , Wang Yizhi , Sun Qi , Zhang Yanbin , Tu Jian , Zhou Zhiming
Published: August 2022

The tensile and compression fatigue deformation tests of AZ31 magnesium alloy were carried out at room temperature, and the activation behavior of {10-12}-{10-12} secondary twins in different loading directions (ND normal direction, RD rolling direction) and different strain amplitude (0.5%, 1%) was studied. The results showed that {10-12}-{10-12} secondary twins were observed on the fracture surface of the fatigue samples in the ND at the strain of 1%. In contrast, no secondary twins were observed in the ND at the strain of 0.5% nor in the RD at the strain of 1% and 0.5%, and the fatigue life in the ND was greater than that in the RD. The analysis showed that the generation of {10-12}-{10-12} secondary twins was associated with the grain size and loading direction and that the fatigue deformation at 1% strain was more likely to generate {10-12}-{10-12} secondary twins due to the large lamellar thickness of the primary twins generated at relatively large strain conditions. The fatigue deformation along the ND tension was more favorable for the activation of multiple {10-12} primary twins, and the interaction of multiple twin variants was more favorable to activate {10-12}-{10-12} secondary twins.
Effects of Electroshock Treatment on Residual Stress and the Geometric Dimensions of Components Fabricated with Wire Arc Additive Manufacturing
Authors: Wu Min , Hu Zeqi , Qin Xunpeng
Published: August 2022

In wire arc additive manufacturing, residual stress is generated from a nonuniform thermal distribution, resulting in the fabricated component demonstrating large deformation. This study explored the effects of electroshock treatment (EST) on the residual stress and geometric dimensions of additive manufacturing components. A special and innovative stress frame was built with wire arc additive manufacturing, on which the EST was conducted. Changes in the residual stress, geometric dimensions, temperature, microstructure, and dislocation distribution on the stress frame during processing were investigated. According to the experimental results, it was concluded that the dislocation density decreased and that the distribution was more homogeneous after EST, which was affected by electron wind force. Finally, the residual stress was reduced, and the geometric dimensions were improved on the substrate.
Effect of Pressure on Densification and Microstructure of W-Cr-Y-Zr Alloy during SPS Consolidated at 1000 °C
Authors: Zhu Huijuan , Tan Xiaoyue , Tu Qingbo , Mao Yiran , Shu Zelin , Chen Jie , Luo Laima , Litnovsky Andrey , Coenen Jan Willem , Linsmeier Christian , Wu Yucheng
Published: August 2022

During the spark plasma sintering (SPS) consolidation process, the pressure affects the densification and microstructure evolution of the sintered body. In this paper, the W-Cr-Y-Zr alloy powder was heated to 1000 °C under different applied pressure conditions using spark plasma sintering process, and the effect of pressure on the densification process and microstructure was analyzed. Due to the low sintering temperature, the crystalline size of all the produced W-Cr-Y-Zr alloy is less than 10 nm, which is close to that of the original powders. Cr-rich phase can be detected in the sintered samples due to spinodal decomposition. It is found in this work that the external pressure will increase the contact area between the powder particles, resulting in a higher local pressure at the particle contact, which promotes densification by sliding between the particles under the condition of softening of the particle surface. Additionally, according to the viscous flow theory, the viscous flow activation energy decreases with the increase of pressure. This is because the pressure provides additional driving force to the powder viscous flow process and accelerates the powder shrinkage.
Correction: Mugume et al. Complex Changes in Membrane Lipids Associated with the Modification of Autophagy in Arabidopsis. Metabolites 2022, 12, 190
Authors: Mugume Yosia , Ding Geng , Dueñas Maria , Liu Meiling , Lee Young-Jin , Nikolau Basil , Bassham Diane
Published: August 2022

In the original article [...]
Stability of Metabolomic Content during Sample Preparation: Blood and Brain Tissues
Authors: Fomenko Maxim V. , Yanshole Lyudmila V. , Tsentalovich Yuri P.
Published: August 2022

Thermal and enzymatic reactions can significantly change the tissue metabolomic content during the sample preparation. In this work, we evaluated the stability of metabolites in human whole blood, serum, and rat brain, as well as in metabolomic extracts from these tissues. We measured the concentrations of 63 metabolites in brain and 52 metabolites in blood. We have shown that metabolites in the extracts from biological tissues are stable within 24 h at 4 °C. Serum and whole blood metabolomes are also rather stable, changes in metabolomic content of the whole blood homogenate become apparent only after 1–2 h of incubation at 4 °C, and become strong after 24 h. The most significant changes correspond to energy metabolites: the concentrations of ATP and ADP decrease fivefold, and the concentrations of NAD, NADH, and NADPH decrease below the detectable level. A statistically significant increase was observed for AMP, IMP, hypoxanthine, and nicotinamide. The brain tissue is much more metabolically active than human blood, and significant metabolomic changes occur already within the first several minutes during the brain harvest and sample homogenization. At a longer timescale (hours), noticeable changes were observed for all classes of compounds, including amino acids, organic acids, alcohols, amines, sugars, nitrogenous bases, nucleotides, and nucleosides.
Diffusion-Slip Boundary Conditions for Isothermal Flows in Micro- and Nano-Channels
Authors: Tomy Alwin Michael , Dadzie S. Kokou
Published: August 2022

Continuum description of flows in micro- and nano-systems requires ad hoc addition of effects such as slip at walls, surface diffusion, Knudsen diffusion and others. While all these effects are derived from various phenomenological formulations, a sound theoretical ground unifying these effects and observations is still lacking. In this paper, adopting the definition and existence of various type of flow velocities beyond that of the standard mass velocity, we suggest derivation of model boundary conditions that may systematically justify various diffusion process occurring in micro- and nano-flows where the classical continuum model breaks down. Using these boundary conditions in conjunction with the classical continuum flow equations we present a unified derivation of various expressions of mass flow rates and flow profiles in micro- and nano-channels that fit experimental data and provide new insights into these flow profiles. The methodology is consistent with recasting the Navier–Stokes equations and appears justified for both gas and liquid flows. We conclude that these diffusion type of boundary conditions may be more appropriate to use in simulating flows in micro- and nano-systems and may also be adapted as boundary condition models in other interfacial flow modelling.
Effect of Scanning Speed on Properties of Laser Surface Remelted 304 Stainless Steel
Authors: Chen Yuanlong , Li Xiang , Liu Jinyang , Zhang Yichi , Chen Xuehui
Published: August 2022

In order to study the microstructure and properties of stainless steel after laser surface remelting, based on the theory of laser surface remelting, a simulation model of nanosecond-pulsed laser surface remelted stainless steel was established to study the evolution law of the Marangoni force of the molten pool during laser surface remelting. A single-lane laser remelting experiment was performed to study the variation of the scanning speed on the remelting width, roughness, and layer microtopography. The “S” scanning path was used to remelt the stainless steel surface to investigate the bonding force between the remelted layer and the substrate, the hardness, microscopic morphology, and corrosion resistance. The results show that the viscosity of the liquid metal in the molten pool increases with the increase of the scanning speed. Larger liquid viscosity and smaller surface tension temperature gradients promote a weaker flow of liquid metal, which reduces the velocity of the liquid metal flow in the molten pool. With the increase of scanning speed, the remelting width gradually decreases, but the roughness gradually increases. When the element content of Cr increases, the element content of Fe and O decreases. The surface is covered with an oxide film, the main components of which are oxides of Cr and Fe, the remelted layer is greater than that of the substrate, and the corrosion resistance is improved. Laser surface remelting technology can improve the structure and properties of 304 stainless steel.
Effect of Site and Phenological Status on the Potato Bacterial Rhizomicrobiota
Authors: Cangioli Lisa , Mancini Marco , Baldi Ada , Fagorzi Camilla , Orlandini Simone , Vaccaro Francesca , Mengoni Alessio
Published: August 2022

The potato is the fourth major food crop in the world. Its cultivation can encounter problems, resulting in poor growth and reduced yield. Plant microbiota has shown an ability to increase growth and resistance. However, in the development of effective microbiota manipulation strategies, it is essential to know the effect of environmental variables on microbiota composition and function. Here, we aimed to identify the differential impact of the site of cultivation and plant growth stage on potato rhizosphere microbiota. We performed a 16S rRNA gene amplicon sequencing analysis of rhizospheric soil collected from potato plants grown at four sites in central Italy during two phenological stages. Rhizomicrobiota was mainly composed of members of phyla Acidobacteriota, Actinobacteriota, Chloroflexi, and Proteobacteria and was affected by both the site of cultivation and the plant stages. However, cultivation sites overcome the effect of plant phenological stages. The PiCRUST analysis suggested a high abundance of functions related to the biosynthesis of the siderophore enterobactin. The presence of site-specific taxa and functional profiling of the microbiota could be further exploited in long-term studies to evaluate the possibility of developing biomarkers for traceability of the products and to exploit plant growth-promoting abilities in the native potato microbiota.
Differential Presence of Microplastics and Mesoplastics in Coral Reef and Mangrove Fishes in Isla Grande, Colombia
Authors: Jimenez-Cárdenas Valeria , Luna-Acosta Andrea , Gómez-Méndez Luis David
Published: August 2022

This study aims to determine whether differences exist between the presence of microplastics and mesoplastics in fishes of coral reef and mangrove ecosystems, in Isla Grande, Colombian Caribbean. The collection of three species of coral reef (Centropomus undecimalis, Caranx hippos, and Lutjanus synagris) and three species of mangrove from coral reef (Centropomus undecimalis, Eugerres plumieri, and Archosargus rhomboidalis) were found to have ingested microplastics and mesoplastics, with a significantly higher in the mangrove species than in the coral reef species (1.9 vs. 1.6 items/individual). Furthermore, the average abundance and weight of microplastics and mesoplastics were significantly higher in females than in males (p < 0.05) and the abundance of microplastics and mesoplastics in the intestines was significantly higher than in the stomach (p < 0.05). PE, polyester, PVC, and PET were the most abundant polymers among common plastics found in species of the two habitats. Our findings highlight the importance of more rigorous plastic waste management strategies in areas nearby the coast and mangrove habitats.
Crystal Growth of Osmium(IV) Dioxide in Chlorine-Bearing Hydrothermal Fluids
Authors: Yan Haibo , Liu Zhuoyu , Di Jian , Ding Xing
Published: August 2022

A mineral’s morphology is usually related to its growth process and environment. This study reported crystal growth of OsO2 through hydrolysis experiments of K2OsCl6 at 150–550 °C and 100 MPa to investigate the growth mechanism of OsO2 and the transport and enrichment of Os in chlorine-bearing hydrothermal fluids. Time-series experimental results showed that the OsO2 crystals grow from 40–150 nm irregular nanoparticles to 150–450 nm nanospheres with time. As the temperature and initial solution concentrations increase, OsO2 can form more uniform and larger OsO2 nanosphere crystals, suggesting a positive effect of temperature and initial solution concentration on the crystal growth of OsO2. The results indicate that the nucleation and aggregate growth driven by the hydrolysis of Os–chloride complex controls the early growth of OsO2 crystals for a short duration; however, after the hydrolysis reaches equilibrium, the growth process of OsO2 nanosphere crystals is dominated mostly by the Ostwald ripening, where the diffusion of Os ions along the fluid–nanocrystal boundary facilitates the coarsening. Given that the transport and cycle of Os from the lithosphere to the hydrosphere is controlled mainly by the stability of the Os–chloride complex, OsO2 nanosphere crystals could occur in seafloor hydrothermal vent systems.
Effect of Heat Transfer Driving Force and Ice Seed Loading on the Production of Ice and Salt from a Dilute Brine Treated Using Eutectic Freeze Crystallization
Authors: Spencer Anotidaishe , Chivavava Jemitias , Lewis Alison Emslie
Published: August 2022

Eutectic Freeze Crystallization (EFC) is a separation technology that separates solute from solvent by cooling the brine to a temperature below its eutectic point, such that ice and salt simultaneously crystallize out of the solution. Achieving consistent production of ice and salt at high production rates has been a challenge for EFC. This is due to heat transfer limitations, which are more severe when EFC is applied to dilute brines. This work investigated the effect of the heat transfer driving force, ΔTLMTD, and ice seed loading (SL) on the production of ice and salt from a dilute brine. A 1.45 L stirred crystallizer was used for the experiments at varying coolant temperatures to investigate the effect of ΔTLMTD, and at varying seed masses to investigate the effect of seed loading. It was found that, as the ΔTLMTD increased, the yield of ice and salt increased. This was attributed to the increase in the heat transfer rate as ΔTLMTD and heat transfer rate are directly related. The ice yield was divided between ice in suspension and ice formed on the wall (scale layer), with a majority of the total ice yield being scale ice. Increasing the seed loading (SL) increased the yield of ice in suspension and decreased the yield of scale ice. The seeds allowed for increased surface area for crystallization in the bulk. This allowed for most of the supersaturation to be consumed in the bulk, leaving little supersaturation for crystallization at the wall. This reduced the propensity for scale formation. The reduction in the scale layer increased the heat transfer rate between the bulk and the coolant, allowing for more ice to be formed in suspension.