bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of the Chemical, Physical and Mechanical Characteristics of Electric Arc Furnace Slags and Environmental Evaluation of the Process for Their Utilization as an Aggregate in Bituminous Mixtures
Authors: Terrones-Saeta Juan María , Suárez-Macías Jorge , Moreno-López Evaristo Rafael , Corpas-Iglesias Francisco Antonio
Published: February 2021

Road construction is an activity that demands a significant amount of aggregates for bituminous mixtures. In addition, these aggregates must be of a suitable quality for use, even more so on high traffic roads. In response to this problem, and in order to avoid the extraction of new raw materials, research is being carried out using industrial waste as a substitute for conventional aggregates. In this way, the extraction of raw materials is reduced and landfilling of waste is avoided. However, these wastes must have certain properties and environmental advantages over natural aggregates. Otherwise, the use of waste would not be environmentally beneficial but would be more damaging to the environment. For this reason, this research evaluates the viability of using electric arc furnace slag as aggregates for bituminous mixtures, the main objectives being the determination of the characteristics of the by-product, the particularities and the critical points to be taken into account for its subsequent use in mixtures. At the same time, the environmental advantages of treating this waste to obtain a usable aggregate are evaluated in comparison with the processing of a natural aggregate. The results showed that electric arc furnace slags have a suitable chemical composition and excellent physical and mechanical properties for use in bituminous mixtures, even on high traffic roads. At the same time, it was determined that their use produces a considerable reduction in environmental afflictions. Therefore, it could be affirmed that the use of electric arc furnace slags in bituminous mixtures is recommendable as a way to develop more sustainable materials for construction.
Damage Analysis of Composite CFRP Tubes Using Acoustic Emission Monitoring and Pattern Recognition Approach
Authors: Šofer Michal , Cienciala Jakub , Fusek Martin , Pavlíček Pavel , Moravec Richard
Published: February 2021

The acoustic emission method has been adopted for detection of damage mechanisms in carbon-fiber-reinforced polymer composite tubes during the three-point bending test. The damage evolution process of the individual samples has been monitored using the acoustic emission method, which is one of the non-destructive methods. The obtained data were then subjected to a two-step technique, which combines the unsupervised pattern recognition approach utilizing the short-time frequency spectra with the boundary curve enabling the already clustered data to be additionally filtered. The boundary curve identification has been carried out on the basis of preliminary tensile tests of the carbon fiber sheafs, where, by overlapping the force versus time dependency by the acoustic emission activity versus time dependency, it was possible to identify the boundary which will separate the signals originating from the fiber break from unwanted secondary sources. The application of the presented two-step method resulted in the identification of the failure mechanisms such as matrix cracking, fiber break, decohesion, and debonding. Besides the comparison of the results with already published research papers, the study presents the comprehensive parametric acoustic emission signal analysis of the individual clusters.
Light and Hydrogels: A New Generation of Antimicrobial Materials
Authors: Pierau Lucie , Versace Davy-Louis
Published: February 2021

Nosocomial diseases are becoming a scourge in hospitals worldwide, and new multidrug-resistant microorganisms are appearing at the forefront, significantly increasing the number of deaths. Innovative solutions must emerge to prevent the imminent health crisis risk, and antibacterial hydrogels are one of them. In addition to this, for the past ten years, photochemistry has become an appealing green process attracting continuous attention from scientists in the scope of sustainable development, as it exhibits many advantages over other methods used in polymer chemistry. Therefore, the combination of antimicrobial hydrogels and light has become a matter of course to design innovative antimicrobial materials. In the present review, we focus on the use of photochemistry to highlight two categories of hydrogels: (a) antibacterial hydrogels synthesized via a free-radical photochemical crosslinking process and (b) chemical hydrogels with light-triggered antibacterial properties. Numerous examples of these new types of hydrogels are described, and some notions of photochemistry are introduced.
A Brief Review on Solvent-Free Synthesis of Zeolites
Authors: Mei Jinlin , Duan Aijun , Wang Xilong
Published: February 2021

The traditional hydrothermal method to prepare zeolite will inevitably use a large amount of water as a solvent, which will lead to higher autogenous pressure, low efficiency, and wastewater pollution. The solvent-free method can be used to synthesize various types of zeolites by mechanical mixing, grinding, and heating of solid raw materials, which exhibits the apparent advantages of high yield, low pollution, and high efficiency. This review mainly introduces the development process of solvent-free synthesis, preparation of hierarchical zeolite, morphology control, synthesis mechanism and applications of solvent-free methods. It can be believed that solvent-free methods will become a research focus and have enormous industrial application potential.
Effects of Ti and Cu Addition on Inclusion Modification and Corrosion Behavior in Simulated Coarse-Grained Heat-Affected Zone of Low-Alloy Steels
Authors: Wang Yuhang , Zhang Xian , Wei Wenzhui , Wan Xiangliang , Liu Jing , Wu Kaiming
Published: February 2021

In this paper, the effects of Ti and Cu addition on inclusion modification and corrosion behavior in the simulated coarse-grained heat-affected zone (CGHAZ) of low-alloy steels were investigated by using in-situ scanning vibration electrode technique (SVET), scanning electron microscope/energy-dispersive X-ray spectroscopy (SEM/EDS), and electrochemical workstation. The results demonstrated that the complex inclusions formed in Cu-bearing steel were (Ti, Al, Mn)-Ox-MnS, which was similar to that in base steel. Hence, localized corrosion was initiated by the dissolution of MnS. However, the main inclusions in Ti-bearing steels were modified into TiN-Al2O3/TiN, and the localized corrosion was initiated by the dissolution of high deformation region at inclusion/matrix interface. With increased interface density of inclusions in steels, the corrosion rate increased in the following order: Base steel ≈ Cu-bearing steel < Ti-bearing steel. Owing to the existence of Cu-enriched rust layer, the Cu-bearing steel shows a similar corrosion resistance with base steel.
Surface Modification of Attapulgite by Grafting Cationic Polymers for Treating Dye Wastewaters
Authors: Guo Huan , Xia Kai , Cao Mingzhao , Zhang Xiaodong
Published: February 2021

In this study, the cationic polymer poly-epichlorohydrin-dimethylamine was immobilized on natural attapulgite to improve the dye adsorption capacities. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, nitrogen adsorption-desorption isotherms, scanning electron microscope (SEM) analysis, zeta potential analysis, and particle size analysis were used to determine the characteristics of modified attapulgite. Results showed that the poly-epichlorohydrin-dimethylamine had been successfully grafted onto the surface of attapulgite without altering its crystal structure. After cationic modification, the specific surface area of attapulgite obviously decreased, and its surface zeta potentials possessed positive values in the pH range from 3 to 11. The cation-modified attapulgite displayed high adsorption capacities for anionic dyes, and its maximum adsorption capacities were 237.4 mg/g for Reactive Black 5 and 228.3 mg/g for Reactive Red 239; this is corroborated by Langmuir’s isotherm studies. It was demonstrated that the two reactive dyes could be 100% removed from effluents when cation-modified attapulgite was used in column operation modes. Its treatment capacities were more than three times larger than that of activated carbon. The regeneration study verified better utilization and stability of the fabricated adsorbent in column operation. This work has conclusively confirmed the potential of the new modified attapulgite for effectively treating dye wastewaters.
Toxic Metals Content in Impacted Third Molars and Adjacent Bone Tissue in Different Groups of Patients
Authors: Bryła Ewelina , Dobrzyński Maciej , Konkol Damian , Kuropka Piotr , Styczyńska Marzena , Korczyński Mariusz
Published: February 2021

The aim of the study was to determine the content of: Pb, Cd, Cr, Ni, Fe, Mn, Cu, Zn in the impacted third molars and a fragment of covering bone. Patients were divided according to following criteria: place of residence, age, gender, anatomical location of the removed tooth. Content of Cd, Pb, and Mn in the samples increases with age of the patient. The content of Cd and Pb in the tooth and bone was higher in patients living in Wroclaw. Residents of the Wroclaw had higher Cu content in the teeth, while they had a lower content in the jawbone. In contrast to Cd and Pb, an average of 68% higher concentration of Zn in the jawbone than in the tooth was noted. The content of Cr in tooth was lower by 33% than in the mandible bone and, similarly to the content of Ni, it decreased with age. In women, the Fe content in bone of the jaw was higher than in the removed tooth. The presence of Pb and Cd aggregates is confirmed in all hard tissues of the tooth and bone, in contrast to bioelements which show a stronger tendency to aggregate, essentially within the dentine.
Characteristics, Mechanism and Criterion of Channel Segregation in NbTi Alloy via Numerical Simulations and Experimental Characterizations
Authors: Zhu Baohui , Chen Zhenzhen , Cao Yanfei , Liu Yanchang , Kang Xiuhong , Chen Yun , Liu Hongwei , Fu Paixian , Luan Yikun , Li Dianzhong
Published: February 2021

Channel segregation (CS) is the most typical defect during solidification of NbTi alloy. Based on numerical simulation and experimental characterizations, we deeply elucidated its characteristics, formation mechanism, effecting factor and prediction criterion. According to acid etching, industrial X-ray transmission imaging, 3D X-ray microtomography and chemical analysis, it was found that in a casing ingot, by He cooling, finer grain size, weaker segregation and slighter CS can be obtained compared with air-cooled ingot. The simulation results of macrosegregation show that CS is caused by the strong natural convection in the mushy zone triggered by the thermo-solutal gradient. Its formation can be divided into two stages including channel initiation and growth. In addition, due to the stronger cooling effect of the He treatment, the interdendritic flow velocity becomes smaller, consequently lowering the positive segregation and CS and improving the global homogenization of the final ingot. Finally, to predict the formation of CS, the Rayleigh number model was proposed and its critical value was found to be 15 in NbTi alloy for the first time. When it is lower than the threshold, CS disappears. It provides an effective tool to evaluate and optimize the solidification parameters to fabricate the homogenized NbTi ingot in engineering practice.
Permanent Deformation and Rutting Resistance of Demolition Waste Triple Blends in Unbound Pavement Applications
Authors: Maghool Farshid , Senanayake Muditha , Arulrajah Arul , Horpibulsuk Suksun
Published: February 2021

Virgin quarried materials are becoming increasingly scarce in our environment, and these materials are no longer a viable or economical solution for the construction industry. The construction industry is constantly seeking new markets for recycled waste in civil engineering applications. This research’s primary focus is the optimization of the usage of recycled materials such as recycled glass (RG), crushed brick (CB), and crushed concrete (CC), in pavement base/sub-base applications. Various percentages of RG, up to 40%, were blended with two types of CC in this research. The CC and CB, which were used as triple blends in this research, were utilized for the upper (100% CC) and lower sub-bases (up to 50% CB). This study sought to establish the maximum amount of RG that could be incorporated in the triple blends with CB and CC whilst maintaining an acceptable performance. Thus, a comprehensive series of fundamental and advanced geotechnical laboratory tests, including repeated load triaxial (RLT) and wheel-tracker (WT) tests, were performed to assess the engineering properties and permanent deformation characteristics of these triple blends. The particle-size distribution curve and California Bearing Ratio (CBR) values of all the blends met the minimum requirements. Results of RLT tests confirmed that all the nominated blends were found to provide the resilient modulus value required to be used as pavement materials. The WT results on the triple blend with 15% RG showed that the specimen performed exceptionally well during the test and comfortably met the requirements to be used in pavement applications. Based on the engineering properties and permanent deformation results, up to 15% RG can be suggested for incorporation as an accompanying material in unbound roadwork applications. Subject to the outcomes of future field testing, there might be potential to increase the percentage of RG added in the blends up to 30%.
Challenges in the Forging of Steel-Aluminum Bearing Bushings
Authors: Behrens Bernd-Arno , Uhe Johanna , Petersen Tom , Klose Christian , Thürer Susanne E. , Diefenbach Julian , Chugreeva Anna
Published: February 2021

The current study introduces a method for manufacturing steel–aluminum bearing bushings by compound forging. To study the process, cylindrical bimetal workpieces consisting of steel AISI 4820 (1.7147, 20MnCr5) in the internal diameter and aluminum 6082 (3.2315, AlSi1MgMn) in the external diameter were used. The forming of compounds consisting of dissimilar materials is challenging due to their different thermophysical and mechanical properties. The specific heating concept discussed in this article was developed in order to achieve sufficient formability for both materials simultaneously. By means of tailored heating, the bimetal workpieces were successfully formed to a bearing bushing geometry using two different strategies with different heating durations. A metallurgical bond without any forging defects, e.g., gaps and cracks, was observed in areas of high deformation. The steel–aluminum interface was subsequently examined by optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). It was found that the examined forming process, which utilized steel–aluminum workpieces having no metallurgical bond prior to forming, led to the formation of insular intermetallic phases along the joining zone with a maximum thickness of approximately 5–7 µm. The results of the EDS analysis indicated a prevailing FexAly phase in the resulting intermetallic layer.
Assessment of Titanate Nanolayers in Terms of Their Physicochemical and Biological Properties
Authors: Ehlert Michalina , Radtke Aleksandra , Roszek Katarzyna , Jędrzejewski Tomasz , Piszczek Piotr
Published: February 2021

The surface modification of titanium substrates and its alloys in order to improve their osseointegration properties is one of widely studied issues related to the design and production of modern orthopedic and dental implants. In this paper, we discuss the results concerning Ti6Al4V substrate surface modification by (a) alkaline treatment with a 7 M NaOH solution, and (b) production of a porous coating (anodic oxidation with the use of potential U = 5 V) and then treating its surface in the abovementioned alkaline solution. We compared the apatite-forming ability of unmodified and surface-modified titanium alloy in simulated body fluid (SBF) for 1–4 weeks. Analysis of the X-ray diffraction patterns of synthesized coatings allowed their structure characterization before and after immersing in SBF. The obtained nanolayers were studied using Raman spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and scanning electron microscopy (SEM) images. Elemental analysis was carried out using X-ray energy dispersion spectroscopy (SEM EDX). Wettability and biointegration activity (on the basis of the degree of integration of MG-63 osteoblast-like cells, L929 fibroblasts, and adipose-derived mesenchymal stem cells cultured in vitro on the sample surface) were also evaluated. The obtained results proved that the surfaces of Ti6Al4V and Ti6Al4V covered by TiO2 nanoporous coatings, which were modified by titanate layers, promote apatite formation in the environment of body fluids and possess optimal biointegration properties for fibroblasts and osteoblasts.
Residual Notch Stress Intensity Factors in Welded Joints Evaluated by 3D Numerical Simulations of Arc Welding Processes
Authors: Campagnolo Alberto , Ferro Paolo , Romanin Luca , Meneghetti Giovanni
Published: February 2021

Approaches based on calculating Residual Notch Stress Intensity Factors (R-NSIFs) assume the weld toe to be a sharp V-notch that gives rise to a residual singular stress distribution close to the weld toe. Once R-NSIFs are determined, they might be included in local fatigue criteria for the structural strength assessment of welded joints based on NSIFs due to external cyclic loading. However, the numerical calculation of R-NSIFs through finite element (FE) simulations of the welding process requires extremely refined meshes to properly capture the residual stress singularity. In this context, the Peak Stress Method (PSM) has recently been adopted to estimate R-NSIFs due to residual stresses by means of coarse meshes of 2D 4-node plane or 3D 8-node brick elements. The aim of this work is to investigate the applicability of the PSM to estimate R-NSIFs in a butt-welded joint using coarse meshes of 3D 10-node tetra elements. The R-NSIF distribution at the weld toe line is estimated by applying the PSM to coarse meshes of 3D 10-node tetra elements, and the results are in agreement with those obtained using 3D 8-node brick elements. Accordingly, the PSM based on tetra elements further enhances the rapid estimation of R-NSIFs using coarse meshes and could be effective in analyzing complex 3D joint geometries.
Effect of Aluminium Powder on Kaolin-Based Geopolymer Characteristic and Removal of Cu2+
Authors: Ariffin Nurliyana , Abdullah Mohd Mustafa Al Bakri , Postawa Przemysław , Zamree Abd Rahim Shayfull , Mohd Arif Zainol Mohd Remy Rozainy , Putra Jaya Ramadhansyah , Śliwa Agata , Omar Mohd Firdaus , Wysłocki Jerzy J. , Błoch Katarzyna , Nabiałek Marcin
Published: February 2021

This current work focuses on the synthesis of geopolymer-based adsorbent which uses kaolin as a source material, mixed with alkali solution consisting of 10 M NaOH and Na2SiO3 as well as aluminium powder as a foaming agent. The experimental range for the aluminium powder was between 0.6, 0.8, 1.0 and 1.2wt%. The structure, properties and characterization of the geopolymer were examined using X-Ray Diffraction (XRD), Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Adsorption capacity and porosity were analysed based on various percentages of aluminium powder added. The results indicate that the use of aluminium powder exhibited a better pore size distribution and higher porosity, suggesting a better heavy metal removal. The maximum adsorption capacity of Cu2+ approached approximately 98%. The findings indicate that 0.8% aluminium powder was the optimal aluminium powder content for geopolymer adsorbent. The removal efficiency was affected by pH, adsorbent dosage and contact time. The optimum removal capacity of Cu2+ was obtained at pH 6 with 1.5 g geopolymer adsorbent and 4 h contact time. Therefore, it can be concluded that the increase in porosity increases the adsorption of Cu2+.
Molybdenum Oxide Thin Films Grown on Flexible ITO-Coated PET Substrates
Authors: Marciel Alice , Graça Manuel , Bastos Alexandre , Pereira Luiz , Suresh Kumar Jakka , Borges Joel , Vaz Filipe , Peres Marco , Magalhães Sergio , Lorenz Katharina , Silva Rui
Published: February 2021

Molybdenum oxide thin films were deposited on stiff and flexible substrates by reactive DC magnetron sputtering. Two sets of samples were prepared. The first with different O2/Ar flow rate ratios and the second, fixing the oxygen content, with different time of deposition. As the O2/Ar flow rate ratio varies from 0 up to 0.56, a threshold was found, ranging from crystalline to amorphous nature, and from a nontransparent appearance with metallic-like electrical conductivity to transparent and dielectric behaviour. From the second set, all transparent, the MoOx films present a compact/dense and featureless morphology with thickness from 190 up to 910 nm, depending on the time of deposition. Their structure was corroborated by XPS and Rutherford Backscattering Spectrometry (RBS) and density measurements were performed by RBS and X-ray reflectivity (XRR), revealing a value of 2.4 g/cm3. The surface roughness is in the order of a few nanometers and the maxima optical transmission, in the visible range, is around 89%. Electrochemical cyclic voltammograms showed noticeable color reversibility and reproducibility on the flexible substrates opening new framework possibilities for new electrochomic devices.
Measurements of Density of Liquid Oxides with an Aero-Acoustic Levitator
Authors: Ushakov Sergey V. , Niessen Jonas , Quirinale Dante G. , Prieler Robert , Navrotsky Alexandra , Telle Rainer
Published: February 2021

Densities of liquid oxide melts with melting temperatures above 2000 °C are required to establish mixing models in the liquid state for thermodynamic modeling and advanced additive manufacturing and laser welding of ceramics. Accurate measurements of molten rare earth oxide density were recently reported from experiments with an electrostatic levitator on board the International Space Station. In this work, we present an approach to terrestrial measurements of density and thermal expansion of liquid oxides from high-speed videography using an aero-acoustic levitator with laser heating and machine vision algorithms. The following density values for liquid oxides at melting temperature were obtained: Y2O3 4.6 ± 0.15; Yb2O3 8.4 ± 0.2; Zr0.9Y0.1O1.95 4.7 ± 0.2; Zr0.95Y0.05O1.975 4.9 ± 0.2; HfO2 8.2 ± 0.3 g/cm3. The accuracy of density and thermal expansion measurements can be improved by employing backlight illumination, spectropyrometry and a multi-emitter acoustic levitator.
Enhanced Antiobesity Efficacy of Tryptophan Using the Nanoformulation of Dendropanax morbifera Extract Mediated with ZnO Nanoparticle
Authors: You Wenying , Ahn Jong Chan , Boopathi Vinothini , Arunkumar Lakshminarayanan , Rupa Esrat Jahan , Akter Reshmi , Kong Byoung Man , Lee Geun Sik , Yang Deok Chun , Kang Se Chan , Liu Jingjing
Published: February 2021

Green synthesis of metal nanoparticles from medicinal plants has provided a broad scope in biomedical research and functional food formulations due to low toxicity. Dendropanax morbifera (DM) is a versatile traditional medicine used for various inflammatory diseases due to its extensive antioxidant activity. We investigated DM as a natural capping agent for Zn2+ ions and coloaded it with tryptophan for its penetration and antiobesity behavior. DM zinc oxide nanoparticles (DM-ZnO NPs) were prepared and then entrapped with tryptophan (DM-ZnO-Try nanoemulsion (NE)) for stable formulation using the O/W nanoemulsion method. The hydrodynamic sizes measured by dynamic light scattering for DM-ZnO NPs and DM-ZnO-Try NE are about 146.26 ± 3.31 and 151.16 ± 3.59 nm, respectively. TEM and SEM reveal its morphology. In vitro analysis on both NPs and NE was non-toxic to RAW 264.7 and 3T3-L1 preadipocyte cell line. It significantly reduced the accumulated lipids through lipolysis performed at 10 ug/mL in 3T3-L1 preadipocyte cells. NE suppresses the differentiation of 3T3-L1 adipocytes and lowers triglycerides. Further, the substantial reduction of lipid content is evident with Oil Red O staining and OD measurement. In this present study, the synergetic effect of DM-ZnO NPs and tryptophan is reported, which provides a way for more detailed research on its efficacy for obesity and obesity-associated disorders.
Microstructure and Mechanical Properties of Alumina Composites with Addition of Structurally Modified 2D Ti3C2 (MXene) Phase
Authors: Cygan Tomasz , Wozniak Jaroslaw , Petrus Mateusz , Lachowski Artur , Pawlak Wojciech , Adamczyk-Cieślak Bogusława , Jastrzębska Agnieszka , Rozmysłowska-Wojciechowska Anita , Wojciechowski Tomasz , Ziemkowska Wanda , Olszyna Andrzej
Published: February 2021

This study presents new findings related to the incorporation of MXene phases into ceramic. Aluminium oxide and synthesised Ti3C2 were utilised as starting materials. Knowing the tendency of MXenes to oxidation and degradation, particularly at higher temperatures, structural modifications were proposed. They consisted of creating the metallic layer on the Ti3C2, by sputtering the titanium or molybdenum. To prepare the composites, powder metallurgy and spark plasma sintering (SPS) techniques were adopted. In order to evaluate the effectiveness of the applied modifications, the emphasis of the research was placed on microstructural analysis. In addition, the mechanical properties of the obtained sinters were examined. Observations revealed significant changes in the MXenes degradation process, from porous areas with TiC particles (for unmodified Ti3C2), to in situ creation of graphitic carbon (in the case of Ti3C2-Ti/Mo). Moreover, the fracture changed from purely intergranular to cracking with high participation of transgranular mode, analogously. In addition, the results obtained showed an improvement in the mechanical properties for composites with Ti/Mo modifications (an increase of 10% and 15% in hardness and fracture toughness respectively, for specimens with 0.5 wt.% Ti3C2-Mo). For unmodified Ti3C2, enormously cracked areas with spatters emerged during tests, making the measurements impossible to perform.
3D Plotting of Silica/Collagen Xerogel Granules in an Alginate Matrix for Tissue-Engineered Bone Implants
Authors: Rößler Sina , Brückner Andreas , Kruppke Iris , Wiesmann Hans-Peter , Hanke Thomas , Kruppke Benjamin
Published: February 2021

Today, materials designed for bone regeneration are requested to be degradable and resorbable, bioactive, porous, and osteoconductive, as well as to be an active player in the bone-remodeling process. Multiphasic silica/collagen Xerogels were shown, earlier, to meet these requirements. The aim of the present study was to use these excellent material properties of silica/collagen Xerogels and to process them by additive manufacturing, in this case 3D plotting, to generate implants matching patient specific shapes of fractures or lesions. The concept is to have Xerogel granules as active major components embedded, to a large proportion, in a matrix that binds the granules in the scaffold. By using viscoelastic alginate as matrix, pastes of Xerogel granules were processed via 3D plotting. Moreover, alginate concentration was shown to be the key to a high content of irregularly shaped Xerogel granules embedded in a minimum of matrix phase. Both the alginate matrix and Xerogel granules were also shown to influence viscoelastic behavior of the paste, as well as the dimensionally stability of the scaffolds. In conclusion, 3D plotting of Xerogel granules was successfully established by using viscoelastic properties of alginate as matrix phase.
Study on Acoustic Emission Characteristics of Low-Temperature Asphalt Concrete Cracking Damage
Authors: Yang Kang , Li Dongxue , He Zhaoyi , Zhou Hanlin , Li Jiaqi
Published: February 2021

In this study, asphalt concrete specimens were subjected to a semicircle bending test at −10 °C to simulate the process of the development of cracks in asphalt concrete at low temperature. The acoustic emission parameters were collected during the test, the variation characteristics of acoustic emission parameters were analyzed, and the peakedness value was introduced to evaluate the damage of asphalt concrete. The dynamic evolution of fracture development was analyzed by periods with acoustic emission source location. The results indicate that the damage of asphalt mixtures shows an obvious brittle characteristic at low temperature, acoustic emission signals mainly originate from the crack damage caused by tensile stress, and the strength and number of signals can reflect the degree of crack development. Based on acoustic emission parameters and load curves, the cracking damage of asphalt concrete at low temperature in this study can be divided into three periods: a calm period, a stable development period, and a rapid fracture period. The crack point occurred and propagated upward rapidly in the rapid fracture period. During this period, acoustic emission parameters such as ringing count, acoustic emission energy, and amplitude increased suddenly; furthermore, the peakedness value reached its peak in this period and corresponded well with the low-temperature damage of asphalt concrete. Acoustic emission source location technology can track position of crack points and the propagation path of cracks, reflecting the dynamic evolution process of asphalt concrete crack damage at low temperature.
Chip Appearance Inspection Method for High-Precision SMT Equipment
Authors: Zhang Huiyan , Sun Hao , Shi Peng
Published: February 2021

In order to meet the defect-detection requirements of chips in high-precision surface mount technology (SMT) equipment widely used in the electronic industry, a chip appearance defect-detection method based on multi-order fractional discrete wavelet packet decomposition (DWPD) is proposed in this paper. First, lead and body regions were extracted from chip images using the image segmentation algorithm with asymmetric Laplace mixture model and connected-component labelling algorithm; then, the texture feature of the region to be inspected was extracted with the multi-order fractional DWPD algorithm and the geometric and gradient features were combined to form image features of the region to be inspected before the subset of features was selected from image features with the feature selection algorithm based on the variational Bayesian Gaussian mixture model; and finally, the support vector machine was used to determine whether the region to be inspected was defective. An experiment was conducted on a data set captured in high-precision SMT equipment. The accuracy of the proposed chip appearance defect-detection method is about 93%, which is more accurate than existing ones.
Human–Machine Interface in Transport Systems: An Industrial Overview for More Extended Rail Applications
Authors: Enjalbert Simon , Gandini Livia Maria , Pereda Baños Alexandre , Ricci Stefano , Vanderhaegen Frederic
Published: February 2021

This paper provides an overview of Human Machine Interface (HMI) design and command systems in commercial or experimental operation across transport modes. It presents and comments on different HMIs from the perspective of vehicle automation equipment and simulators of different application domains. Considering the fields of cognition and automation, this investigation highlights human factors and the experiences of different industries according to industrial and literature reviews. Moreover, to better focus the objectives and extend the investigated industrial panorama, the analysis covers the most effective simulators in operation across various transport modes for the training of operators as well as research in the fields of safety and ergonomics. Special focus is given to new technologies that are potentially applicable in future train cabins, e.g., visual displays and haptic-shared controls. Finally, a synthesis of human factors and their limits regarding support for monitoring or driving assistance is proposed.
Advances and Trends in Non-Conventional, Abrasive and Precision Machining
Authors: Deja Mariusz , Markopoulos Angelos P.
Published: February 2021

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Analytical Study on the Cornering Behavior of an Articulated Tracked Vehicle
Authors: Tota Antonio , Galvagno Enrico , Velardocchia Mauro
Published: February 2021

Articulated tracked vehicles have been traditionally studied and appreciated for the extreme maneuverability and mobility flexibility in terms of grade and side slope capabilities. The articulation joint represents an attractive and advantageous solution, if compared to the traditional skid steering operation, by avoiding any trust adjustment between the outside and inside tracks. This paper focuses on the analysis and control of an articulated tracked vehicle characterized by two units connected through a mechanical multiaxial joint that is hydraulically actuated to allow the articulated steering operation. A realistic eight degrees of freedom mathematical model is introduced to include the main nonlinearities involved in the articulated steering behavior. A linearized vehicle model is further proposed to analytically characterize the cornering steady-state and transient behaviors for small lateral accelerations. Finally, a hitch angle controller is designed by proposing a torque-based and a speed-based Proportional Integral Derivative (PID) logics. The controller is also verified by simulating maneuvers typically adopted for handling analysis.
Field-Induced Single-Molecule Magnets of Dysprosium Involving Quinone Derivatives
Authors: Martyanov Konstantin , Flores Gonzalez Jessica , Norkov Sergey , Lefeuvre Bertrand , Dorcet Vincent , Cherkasov Vladimir , Cador Olivier , Kuropatov Viacheslav , Pointillart Fabrice
Published: February 2021

The coordination reaction of the [Dy(hfac)3(H2O)2] units (hfac− = 1,1,1,5,5,5-hexafluoroacetylacetonate) with the two quinone-based derivatives 4,7-di-tert-butyl-2-(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)benzo[d][1,3]dithiole-5,6-dione (L1) and 7,8-dithiabicyclo[4.2.0]octa-1,5-diene-3,4-dione,2,5bis(1,1-dimethylethyl) (L2) led respectively to the complexes [Dy(hfac)3(H2O)(L1)] (1) and [Dy(hfac)3(H2O) (L2)]⋅(C6H14)(CH2Cl2) (2)⋅(C6H14)(CH2Cl2). X-ray structures on single crystal of 1 and 2⋅(C6H14)(CH2Cl2) revealed the coordination of the DyIII on the bischelating oxygenated quinone site and the formation of dimeric species through hydrogen bonds. Ac magnetic measurements highlighted field-induced single-molecule magnet behavior with magnetic relaxation through a Raman process.
Chassis Influence on the Exposure Assessment of a Compact EV during WPT Recharging Operations
Authors: De Santis Valerio , Giaccone Luca , Freschi Fabio
Published: February 2021

In this study, the external magnetic field emitted by a wireless power transfer (WPT) system and the internal electric field induced in human body models during recharging operations of a compact electric vehicle (EV) are evaluated. The magneticfield is calculated with a hybrid scheme coupling the boundary element method with the surface impedance boundary conditions in order to fit the multiscale open-boundary characteristics of the problem. A commercial software is then used to perform numerical dosimetry. Specifically, two realistic anatomical models, both in a driving position and in a standing posture, are considered, and the chassis of the EV is modeled either as a currently employed aluminum alloy and as a futuristic carbon fiber composite panel. Aligned and misaligned coil configurations of the WPT system are considered as well. The analysis of the obtained results shows that the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels are exceeded in the driving position, especially for the carbon fiber chassis, whereas the system is compliant with the basic restrictions, at least for the considered scenarios.
Optimization of Energy Consumption in Chemical Production Based on Descriptive Analytics and Neural Network Modeling
Authors: Shinkevich Alexey I. , Malysheva Tatiana V. , Vertakova Yulia V. , Plotnikov Vladimir A.
Published: February 2021

Improving the energy efficiency of chemical industries and increasing their environmental friendliness requires an assessment of the parameters of consumption and losses of energy resources. The aim of the study is to develop and test a method for solving the problem of optimizing the use of energy resources in chemical production based on the methodology of descriptive statistics and training of neural networks. Research methods: graphic and tabular tools for descriptive data analysis to study the dynamics of the structure of energy carriers and determine possible reserves for reducing their consumption; correlation analysis with the construction of scatter diagrams to identify the dependences of the range of limit values of electricity consumption on the average rate of energy consumption; a method for training neural networks to predict the optimal values of energy consumption; methods of mathematical optimization and standardization. The authors analyzed the trends in the energy intensity of chemical industries with an assessment of the degree of transformation of the structure of the energy portfolio and possible reserves for reducing the specific weight of electrical and thermal energy; determined the dynamics of energy losses at Russian industrial enterprises; established the correlation dependence of the range of limiting values of power consumption on the average rate of power consumption; determined the optimal limiting limits of the norms for the loss of electrical energy by the example of rubbers of solution polymerization. The results of the study can be used in the development of software complexes for intelligent energy systems that allow tracking the dynamics of consumption and losses of energy resources. Using the results allows you to determine the optimal parameters of energy consumption and identify reserves for improving energy efficiency.
Biophysics and Modeling of Mechanotransduction in Neurons: A Review
Authors: Nicoletti Martina , Chiodo Letizia , Loppini Alessandro
Published: February 2021

Mechanosensing is a key feature through which organisms can receive inputs from the environment and convert them into specific functional and behavioral outputs. Mechanosensation occurs in many cells and tissues, regulating a plethora of molecular processes based on the distribution of forces and stresses both at the cell membrane and at the intracellular organelles levels, through complex interactions between cells’ microstructures, cytoskeleton, and extracellular matrix. Although several primary and secondary mechanisms have been shown to contribute to mechanosensation, a fundamental pathway in simple organisms and mammals involves the presence of specialized sensory neurons and the presence of different types of mechanosensitive ion channels on the neuronal cell membrane. In this contribution, we present a review of the main ion channels which have been proven to be significantly involved in mechanotransduction in neurons. Further, we discuss recent studies focused on the biological mechanisms and modeling of mechanosensitive ion channels’ gating, and on mechanotransduction modeling at different scales and levels of details.
Fuzzy Set Qualitative Comparative Analysis of Factors Influencing the Use of Cryptocurrencies in Spanish Households
Authors: Arias-Oliva Mario , de Andrés-Sánchez Jorge , Pelegrín-Borondo Jorge
Published: February 2021

This paper assesses the variables influencing the expansion of cryptocurrency (crypto for short) use in households. To carry on the study we apply a consumer-behavior focus and so-called fuzzy set Qualitative Comparative Analysis (fsQCA). In a previous research, that was grounded on Unified Theory of Acceptance and Use of Technology (UTAUT) and Partial Least Squares (PLS), we found that main factors to explain the intention to use of cryptos by individuals were performance expectancy (in fact, it was the main factor), effort expectancy and facilitating conditions. We did not found evidences about the relevance of social influence, perceived risk and financial literacy. This study revisits these results by applying fsQCA instead PLS. Empirical research on factors influencing cryto use is relatively scarce due to the novelty of blockchain techs, so the present paper expands the literature on this topic by using an original analytical tool in this context. The main contribution of this paper consists in showing empirically that fsQCA provides a complementary and enriching perspective to interpret data about the use of cryptos. We obtain again that the most relevant factor to explain the intention of using cryptocurrencies is perceived expectancy and that also effort expectancy and facilitation conditions are relevant. But also fsQCA has allowed us discovering that despite social influence, perceived risk and financial literacy were not significant in the PLS model, they impact on the intention to use cryptocurrencies when are combined with other factors. Social influence acts as an “enable factor” for the rest of explanatory variables and it is linked positively with intention to use cryptos. Also financial literacy is relevant because its lack is a sufficient condition for the non-acceptance of that blockchain tech. Likewise we have checked that perceived risk influences the intention of using cryptos. However, this influence may be positive or negative depending of the circumstances.
Dynamics of Fourier Modes in Torus Generative Adversarial Networks
Authors: González-Prieto Ángel , Mozo Alberto , Talavera Edgar , Gómez-Canaval Sandra
Published: February 2021

Generative Adversarial Networks (GANs) are powerful machine learning models capable of generating fully synthetic samples of a desired phenomenon with a high resolution. Despite their success, the training process of a GAN is highly unstable, and typically, it is necessary to implement several accessory heuristics to the networks to reach acceptable convergence of the model. In this paper, we introduce a novel method to analyze the convergence and stability in the training of generative adversarial networks. For this purpose, we propose to decompose the objective function of the adversary min–max game defining a periodic GAN into its Fourier series. By studying the dynamics of the truncated Fourier series for the continuous alternating gradient descend algorithm, we are able to approximate the real flow and to identify the main features of the convergence of GAN. This approach is confirmed empirically by studying the training flow in a 2-parametric GAN, aiming to generate an unknown exponential distribution. As a by-product, we show that convergent orbits in GANs are small perturbations of periodic orbits so the Nash equillibria are spiral attractors. This theoretically justifies the slow and unstable training observed in GANs.
Barrier Lyapunov Function-Based Adaptive Back-Stepping Control for Electronic Throttle Control System
Authors: Wang Dapeng , Liu Shaogang , He Youguo , Shen Jie
Published: February 2021

This paper presents an adaptive constraint control approach for Electronic Throttle Control System (ETCS) with asymmetric throttle angle constraints. The adaptive constraint control method, which is based on barrier Lyapunov function (BLF), is designed not only to track the desired throttle angle but also to guarantee no violation on the throttle angle constraints. An ETC mathematic model with complex non-linear system is considered and the asymmetric barrier Lyapunov function (ABLF) is introduced into the design of the controller. Based on Lyapunov stability theory, it can be concluded that the proposed controller can guarantee the stability of the whole system and uniformly converge the state error to track the desired throttle angle. The results of simulations show that the proposed controller can ensure that there is no violation on the throttle angle constraints.
An SVEIRE Model of Tuberculosis to Assess the Effect of an Imperfect Vaccine and Other Exogenous Factors
Authors: Sulayman Fatima , Abdullah Farah Aini , Mohd Mohd Hafiz
Published: February 2021

This study extends a deterministic mathematical model for the dynamics of tuberculosis transmission to examine the impact of an imperfect vaccine and other exogenous factors, such as re-infection among treated individuals and exogenous re-infection. The qualitative behaviors of the model are investigated, covering many distinct aspects of the transmission of the disease. The proposed model is observed to show a backward bifurcation, even when Rv<1. As such, we assume that diminishing Rv to less than unity is not effective for the elimination of tuberculosis. Furthermore, the results reveal that an imperfect tuberculosis vaccine is always effective at reducing the spread of infectious diseases within the population, though the general effect increases with the increase in effectiveness and coverage. In particular, it is shown that a limited portion of people being vaccinated at steady-state and vaccine efficacy assume a equivalent role in decreasing disease burden. From the numerical simulation, it is shown that using an imperfect vaccine lead to effective control of tuberculosis in a population, provided that the efficacy of the vaccine and its coverage are reasonably high.
Delay Equivalences in Tuning PID Control for the Double Integrator Plus Dead-Time
Authors: Huba Mikulas , Vrancic Damir
Published: February 2021

The paper investigates and explains a new simple analytical tuning of proportional-integrative-derivative (PID) controllers. In combination with nth order series binomial low-pass filters, they are to be applied to the double-integrator-plus-dead-time (DIPDT) plant models. With respect to the use of derivatives, it should be understood that the design of appropriate filters is not only an implementation problem. Rather, it is also critical for the resulting performance, robustness and noise attenuation. To simplify controller commissioning, integrated tuning procedures (ITPs) based on three different concepts of filter delay equivalences are presented. For simultaneous determination of controller + filter parameters, the design uses the multiple real dominant poles method. The excellent control loop performance in a noisy environment and the specific advantages and disadvantages of the resulting equivalences are discussed. The results show that none of them is globally optimal. Each of them is advantageous only for certain noise levels and the desired degree of their filtering.
A New Method of Measurement Matrix Optimization for Compressed Sensing Based on Alternating Minimization
Authors: Yi Renjie , Cui Chen , Wu Biao , Gong Yang
Published: February 2021

In this paper, a new method of measurement matrix optimization for compressed sensing based on alternating minimization is introduced. The optimal measurement matrix is formulated in terms of minimizing the Frobenius norm of the difference between the Gram matrix of sensing matrix and the target one. The method considers the simultaneous minimization of the mutual coherence indexes including maximum mutual coherence μmax, t-averaged mutual coherence μave and global mutual coherence μall, and solves the problem that minimizing a single index usually results in the deterioration of the others. Firstly, the threshold of the shrinkage function is raised to be higher than the Welch bound and the relaxed Equiangular Tight Frame obtained by applying the new function to the Gram matrix is taken as the initial target Gram matrix, which reduces μave and solves the problem that μmax would be larger caused by the lower threshold in the known shrinkage function. Then a new target Gram matrix is obtained by sequentially applying rank reduction and eigenvalue averaging to the initial one, leading to lower. The analytical solutions of measurement matrix are derived by SVD and an alternating scheme is adopted in the method. Simulation results show that the proposed method simultaneously reduces the above three indexes and outperforms the known algorithms in terms of reconstruction performance.