bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Feature Extraction of Ship-Radiated Noise Based on Multiscale Fuzzy Dispersion Entropy
Authors: Li Yuxing , Lou Yilan , Liang Lili , Zhang Shuai
Published: May 2023

In recent years, fuzzy dispersion entropy (FDE) has been proposed and used in the feature extraction of various types of signals. However, FDE can only analyze a signal from a single time scale during practical application and ignores some important information. In order to overcome this drawback, on the basis of FDE, this paper introduces the concept of multiscale process and proposes multiscale FDE (MFDE), based on which an MFDE-based feature extraction method for ship-radiated noise is proposed. The experimental results of the simulated signals show that MFDE can reflect the changes in signal complexity, frequency, and amplitude, which can be applied in signal feature extraction; in addition, the measured experimental results demonstrate that the MFDE-based feature extraction method has a better feature extraction effect on ship-radiated noise, and the highest recognition rate is 99.5%, which is an improvement of 31.9% compared to the recognition rate of a single time scale. All the results show that MFDE can be better applied to the feature extraction and identification classification of ship-radiated noise.
Strain Localisation and Fracture of Nuclear Reactor Core Materials
Authors: Griffiths Malcolm
Published: May 2023

The production of prismatic dislocation loops in nuclear reactor core materials results in hardening because the loops impede dislocation motion. Yielding often occurs by a localised clearing of the loops through interactions with gliding dislocations called channeling. The cleared channels represent a softer material within which most of the subsequent deformation is localized. Channeling is often associated with hypothetical dislocation pileup and intergranular cracking in reactor components although the channels themselves do not amplify stress as one would expect from a pileup. The channels are often similar in appearance to twins leading to the possibility that twins are sometimes mistakenly identified as channels. Neither twins nor dislocation channels, which are bulk shears, produce the same stress conditions as a pileup on a single plane. At high doses, when cavities are produced (either He-stabilised bubbles at low temperatures or voids at high temperatures), there can be reduced ductility because the material is already in an equivalent advanced stage of microscopic necking. He-stabilised cavities form preferentially on grain boundaries and at precipitate or incoherent twin/ε-martensite interfaces. The higher planar density of the cavities, coupled with the incompatibility at the interface, results in a preferential failure known as He embrittlement. Strain localisation and inter- or intragranular failure are dependent on many factors that are ultimately microstructural in nature. The mechanisms are described and discussed in relation to reactor core materials.
Intracranial Aneurysms: Relevance of Superposed Blood Pulse Waves and Tobacco Smoke?
Authors: Barz Ulrich , Schreiber Almut , Barz Helmut
Published: May 2023

Background: Intracranial aneurysms (IAs) are found in around 3–4% of elderly people. The authors attempt to answer why IAs develop exclusively in the circle of Willis (CW) and why IAs in the frontal cerebral arteries are unusually frequent in men. Methods: The location and frequency of IAs were analyzed using relevant publications (MEDLINE and PubMed). Results: It is suggested that superposed blood pulse waves may have an influence on the development of IAs. The superposition of blood pulse waves is caused by the meeting of the bilateral cerebral arteries in the CW. The predominance of IAs in women is striking (about 1.7:1). However, IAs in the anterior cerebral arteries and anterior communicating artery are significantly more common in men than in women (approximately 1.8:1). The authors hypothesize that greater nicotine abuse in men may explain this phenomenon. Cigarette smoke apparently reaches the anterior cerebral arteries via the olfactory pathway. Conclusion: It seems possible that superposed pulse waves are a substantial factor in the occurrence of IAs. The toxic effects of tobacco smoke appear to have greater impact on IA development than the sex-specific influences that are responsible for the predominance of IAs in women.
The Increasing Coastal Urbanization in the Mediterranean Environment: The State of the Art in Italy
Authors: Smiraglia Daniela , Cavalli Alice , Giuliani Chiara , Assennato Francesca
Published: May 2023

This paper describes the state of the art of urbanization in Italian coastal areas in 2021, both at national and regional level. Moreover, we focused on six coastal municipalities, aiming to evaluate land consumption in relation to population dynamics between 2012 and 2021 and assessing per capita consumed land in each municipality. Finally, an analysis of land consumption in specific areas prone to natural risks along the coastline (hydraulic, landslide and seismic, hazard) was provided. We considered areas of medium hydraulic hazard, of high and very high landslide hazard, and of high and very high seismic hazard. The results indicate an intense process of urbanization in the first 1000 m from the coastline at national, regional, and municipal levels, which is also increasing in the presence of stabilization or dwindling inhabitants. Furthermore, urbanization is also affected by geomorphology, leading to the developments of settlements in the most accessible areas, such as coastal plains, without taking into consideration the presence of natural hazards. The study highlights the importance of monitoring land consumption to the understanding of processes related to urbanization in coastal areas, from the perspective of future effective policies and to support sustainable planning.
Multi-Scenario Simulation and Assessment of Ecosystem Service Value at the City Level from the Perspective of “Production–Living–Ecological” Spaces: A Case Study of Haikou, China
Authors: Chen Jie , Fu Hui , Chen Shengtian
Published: May 2023

Structural changes in land use caused by urban development are one of the most important threats to ecosystem services. An in-depth study of the impacts that different land use patterns have on ecosystem service value (ESV) can provide guidance for sustainable urban planning and ecological conservation. In this research, we sought to explore the response mechanisms of ecosystem services under different urban development scenarios from the perspective of “production–living–ecological” space (PLES). This study combined the Patch-generating Land Use Simulation (PLUS) model and ESV equivalent factor method to simulate the PLES and ESV of Haikou in 2035 under three scenarios of business as usual (BAU), ecological conservation (EC) and economic development (ED), and used the spatial superposition method, transfer matrix, and optimized cross-sensitivity analysis to explore the influence of the PLES on ecosystem services. The ESV of Haikou showed a declining trend from 2010 to 2020 under the influence of PLES changes and was at risk of further decline in the future. The reduction in the value of the water supply service constituted a major part of the loss of ESV. The simulation results demonstrated that the EC scenario had the most rational and ecologically efficient allocation of PLES, with the highest ESV and the lowest sensitivity to PLES changes. The results of this research can serve as an important reference for optimizing the urban land use structure and maintaining the stability of ecosystem services.
Establishing a Reliable Assessment of the Green View Index Based on Image Classification Techniques, Estimation, and a Hypothesis Testing Route
Authors: Liu Yiming , Pan Xiangxiang , Liu Qing , Li Guicai
Published: May 2023

Sustainable development policies and spatial planning for maintaining greenery are crucial for all major cities in the world, and the measurement of green space indicators in planning practice needs to evolve in response to the demands of the times and technological drivers. This study explores an informal urban green space indicator, the green view index (GVI), which uses the visual perception of an observer to measure the quality of urban space by simulating the pedestrian perspective of the road in street-view image data and then calculating the proportion of vegetation in the road landscape. The GVI is different from macro indicators, such as public recreational green space, forest coverage, and green space rate, which are derived from planning data or remote sensing data in traditional urban planning; it starts from the bottom-up perception of individual residents and is more relevant to their subjective demands. At present, most international cities have made outstanding achievements in controlling public recreational green space, forest coverage, green space rates, and other macrolevel indicators of urban spatial quality; however, with the promotion of the concept of “human-oriented” urban planning, the potential restoration of urban spatial quality at the microlevel is gradually being recognized. To ensure the efficiency and reliability of this study, inspired by computer vision techniques and related GVI studies, a research method based on chromaticity was built to identify the proportions of green vegetation in street view images, and the credibility was improved by eliminating unreliable data. By using this method, we could evaluate a city at an overall scale instead of the previous block scale. The final research result showed that Shenzhen is friendly to human visual senses, and the GVI of the streets in developed areas is generally higher than that in developing areas. The geostatistical analysis of the green viewpoint data provides a more intuitive guide for researchers and planners, and it is believed to inform the planning and design of environmentally friendly, smart, and sustainable future cities.
Simultaneous Bilateral Femoral Osteonecrosis in Gaucher Disease
Authors: Cohen Daniel , Levy Yadin , Bar-Ziv Yaron , Revel-Vilk Shoshana , Zimran Ari , Lebel Ehud
Published: May 2023

Gaucher disease (GD) is one of the most common lysosomal storage disorders. Bone complications are the most critical irreversible consequence of GD. Osteonecrosis (ON) of the femoral head inevitably leads to osteoarthritis and may be managed by hip arthroplasty. The introduction and worldwide use of therapeutic agents (specifically enzyme replacement therapies (ERT)) lowered the prevalence of osteonecrosis events per patient. We present the cases of two female patients who sustained simultaneous bilateral femoral head osteonecrosis after receiving ERT for long periods while exposed to concomitant risk factors related to femoral head ON. Both patients suffered severe pain and deterioration of their daily activity capabilities, and thus, were offered bilateral hip arthroplasty. Surgery was performed in both hip joints during the same procedure. The current report highlights several key aspects of femoral head ON in young patients with GD.
Acute Promyelocytic Leukemia and Severe Differentiation Syndrome in Pregnancy—A Management Challenge
Authors: Droc Gabriela , Stancioaica Maria Camelia , Soare Corina Gabriela , Stefan Mihai-Gabriel , Ingustu Daiana , Martac Cristina , Coriu Daniel , Isac Sebastian , Suciu Nicolae , Andrei Stefan
Published: May 2023

Acute promyelocytic leukemia (APL) is generated by the PML-RARA fusion gene. In patients suffering from APL, the early diagnosis and treatment are essential in the successful management. We reported a case of a 27-year-old 17th-week pregnant patient diagnosed with APL. After an extensive hematological diagnostic panel, the acute promyelocytic leukemia was confirmed, and the patient received all-trans retinoic acid (ATRA), idarubicin (IDA), and dexamethasone, following national guidelines. Due to ATRA-related differentiation syndrome, the therapy was adjusted, and hydroxycarbamide was added with a good outcome. The patient was admitted to the ICU secondary to hypoxemic respiratory failure on the 2nd day after hospital admission. Our patient received an individualized drug combination, adjusted by the clinical response. Furthermore, the drugs used in APL treatment are all teratogenic. Despite various major complications, including severe acute respiratory distress syndrome (ARDS), which needed mechanical ventilation; ICU-acquired myopathy; and spontaneous abortion, the patient had a good outcome and was transferred from the ICU after a total stay of 40 days. APL during pregnancy is a rare entity of intermediate-risk APL. Our study emphasized the need for individualized therapy in a rare case of a pregnant woman diagnosed with a potentially fatal hematologic disease.
Experimental Study on Reinforcement of Reef Limestone by Magnetic Anchoring System
Authors: Liu Jie , Guo Jianxiang , Yu Fan , Li Zheng
Published: May 2023

The magnetic anchoring system (MAS) for reef limestone reinforcement is proposed in this paper. The mix proportion of the artificial reef limestone was designed, and the parameters of the MAS were determined through orthogonal tests. The effect of the magnetic field on the anchoring materials was analyzed using XRD and the nitrogen adsorption method. The results indicate that the designed artificial reef limestone can be used in place of in situ rock samples for laboratory tests. In air, the bond samples of the anchoring material and reef limestone experienced cohesion failure of the artificial reef limestone. However, in seawater, it was cohesion failure of the reef limestone and interface adhesion failure. During the pull-out test, the reef limestone specimen reinforced by MAS showed interface failure between the anchoring material and the rock mass. The Fe3O4 powder present in the anchoring material has the ability to migrate towards the anchor, thereby enhancing the density of the anchoring material. This, in turn, helps to eliminate the free water present in the anchor hole, and consequently, improves the bonding effect of the interface. The reinforcement effect of MAS is particularly advantageous for rock reinforcement under complex working conditions.
The Effect of Specimen Size on Acoustic Emission Parameters and Approximate Position of Defects Obtained during Destructive Testing of Cementitious and Alkali-Activated Degraded Fine-Grained Materials
Authors: Topolář Libor , Kocáb Dalibor , Hrubý Petr , Jakubka Luboš , Hoduláková Michaela , Halamová Romana
Published: May 2023

Two sizes of test samples were selected to investigate the effect of size on the level of degradation. The smaller test specimens had dimensions of 40 × 40 × 160 mm, and the larger ones had dimensions of 100 × 100 × 400 mm. Both sizes of test specimens were always made of the same mortar. In one case, Blast Furnace Cement was chosen as the binder. In the other case, it was an alkali-activated material as a possibly more environmentally economical substitute. Both types of material were deposited in three degrading solutions: magnesium sulphate, ammonium nitrate and acetic acid. The reference set was stored in a water bath. After six months in the degradation solutions, a static elastic modulus was determined for the specimens during this test, and the acoustic emission was measured. Acoustic emission parameters were evaluated: the number of hits, the amplitude magnitude and a slope from the amplitude magnitude versus time (this slope should correspond to the Kaiser effect). For most of the parameters studied, the size effect was more evident for the more degraded specimens, i.e., those placed in aggressive solutions. The approximate location of emerging defects was also determined using linear localisation for smaller specimens where the degradation effect was more significant. In more aggressive environments (acetic acid, ammonium nitrate), the higher resistance of materials based on alkaline-activated slag was more evident, even in the case of larger test bodies. The experiments show that the acoustic emission results agree with the results of the static modulus of elasticity.
An Analysis of the Influence of Surface Roughness and Clearance on the Dynamic Behavior of Deep Groove Ball Bearings Using Artificial Neural Networks
Authors: Knežević Ivan , Rackov Milan , Kanović Željko , Buljević Anja , Antić Aco , Tica Milan , Živković Aleksandar
Published: May 2023

The deep groove ball bearing is one of the most important components of the rotary motion system and is the research subject in this paper. After factory assembly, new ball bearings need to pass quality control. The conventional approach relies on measuring the vibration amplitudes for each unit and sorting them into classes according to the vibration level. In this paper, based on experimental research, models are created to predict the vibration class and analyze the dynamic behavior of new ball bearings. The models are based on artificial neural networks. A feedforward multilayer perceptron (MLP) was applied, and a backpropagation learning algorithm was used. A specific method of training groups of artificial neural networks was applied, where each network provided an answer to the input within the group, and the final answer was the mean value of the answers of all networks in the group. The models achieved a prediction accuracy of over 90%. The main aim of the research was to construct models that are able to predict the vibration class of a new ball bearing based on the geometric parameters of the bearing rings. The models are also applied to analyze the influence of surface roughness of the raceways and the internal radial clearance on bearing vibrations.
HD-SiO2/SiO2 Sol@PDMS Superhydrophobic Coating with Good Durability and Anti-Corrosion for Protection of Al Sheets
Authors: Xia Ruohan , Zhang Bing , Dong Kousuo , Yan Yao , Guan Zisheng
Published: May 2023

Superhydrophobic coatings with excellent water-repellent properties imply a wide range of application areas. However, improvements are needed in terms of stability and complex processing procedures. In the present study, a superhydrophobic coating on Al sheets was prepared by mixing hexadecyltrimethoxysilane (HDTMS)-modified SiO2 nanoparticles and acid-catalyzed silica sols (HD-SiO2/SiO2 Sol) with polydimethylsiloxane (PDMS) binder. The HD-SiO2 nanoparticles and acid-catalyzed silica sol (SiO2 sol) form a binary graded micro-nanostructure, providing excellent superhydrophobicity (Water Contact Angle = 158.5°, Sliding angle = 0°). Superhydrophobic coatings with excellent water-repellent properties have potential for corrosion prevention. However the commonly used organic resins have poor chemical and mechanical properties. In the present study, the results of outdoor exposure for 30 days, immersion in acid and alkaline solutions for 24 h, grit abrasion, and water impact experiments, respectively, showed that the prepared superhydrophobic coating has good wear resistance. The integrated superhydrophobic coating on the Al sheets exhibited good corrosion inhibition with an efficiency (η) of 98.9%, which is much higher than that of the uncoated sheets. The present study provides a promising approach for producing stable superhydrophobic coatings at a low cost, with the potential to supplant conventional organic resin anti-corrosion coatings.
Study on Reversible Solubilization by Adjusting Surfactant Properties
Authors: Takata Youichi , Uchikura Amu
Published: May 2023

Solubilization allows us to dissolve hydrophobic materials in water and to carry them to where they are needed. The purpose of this study is to control solubilization, especially the release of solubilized materials, via external stimulation. An amphoteric surfactant, dodecyldimethyl(3-sulfopropyl)ammonium hydroxide inner salt (SB-12), was employed, and a pH change was chosen as the external stimulus. We measured the surface tension of an SB-12 solution via the Wilhelmy method, and the absorbance of a solubilized solution was determined using UV-Vis spectroscopy at various pH values. The surface tension was almost the same at any pH, contrary to our expectations. This result suggests that the adsorption behavior and micelle formation of SB-12 were not affected by pH very much. On the other hand, the solubilization behavior remarkably depended on the pH. In particular, the solubilization ability under the basic condition was much larger than that under the acidic and neutral conditions. Taking advantage of such a difference in solubilization ability under some pH conditions, the solubilized material could be completely removed from the solution. Thus, we clarified the mechanism of release for solubilized materials due to a pH change.
Heterogeneous Catalysts for Glycerol Biorefineries: Hydrogenolysis to 1,2-Propylene Glycol
Authors: Gatti Martín N. , Perez Federico M. , Santori Gerardo F. , Nichio Nora N. , Pompeo Francisco
Published: May 2023

Research on the use of biomass resources for the generation of energy and chemical compounds is of great interest worldwide. The development and growth of the biodiesel industry has led to a parallel market for the supply of glycerol, its main by-product. Its wide availability and relatively low cost as a raw material make glycerol a basic component for obtaining various chemical products and allows for the development of a biorefinery around biodiesel plants, through the technological integration of different production processes. This work proposes a review of one of the reactions of interest in the biorefinery environment: the hydrogenolysis of glycerol to 1,2-propylene glycol. The article reviews more than 300 references, covering literature from about 20 years, focusing on the heterogeneous catalysts used for the production of glycol. In this sense, from about 175 catalysts, between bulk and supported ones, were revised and discussed critically, based on noble metals, such as Ru, Pt, Pd, and non-noble metals as Cu, Ni, Co, both in liquid (2–10 MPa, 120–260 °C) and vapor phase (0.1 MPa, 200–300 °C). Then, the effect of the main operational and decision variables, such as temperature, pressure, catalyst/glycerol mass ratio, space velocity, and H2 flow, are discussed, depending on the reactors employed. Finally, the formulation of several kinetic models and stability studies are presented, discussing the main deactivation mechanisms of the catalytic systems such as coking, leaching, and sintering, and the presence of impurities in the glycerol feed. It is expected that this work will serve as a tool for the development of more efficient catalytic materials and processes towards the future projection of glycerol biorefineries.
Study on the Utilization of Waste Thermoset Glass Fiber-Reinforced Polymer in Normal Strength Concrete and Controlled Low Strength Material
Authors: Li Yeou-Fong , Hsu Yi-Wei , Syu Jin-Yuan , Chen Bian-Yu , Song Bo
Published: May 2023

Thermoset glass fiber-reinforced polymers (GFRP) have been widely used in manufacturing and construction for nearly half a century, but the large amount of waste produced by this material is difficult to dispose of. In an effort to address this issue, this research investigates the reuse of thermoset GFRP waste in normal strength concrete (NSC) and controlled low-strength materials (CLSM). The mechanical performance and workability of the resulting concrete were also evaluated. To prepare the concrete specimens, the thermoset GFRP waste was first pulverized into granular pieces, which were then mixed with cement, fly ash, and water to form cylindrical concrete specimens. The results showed that when the proportion of thermoset GFRP waste aggregate in the concrete increased, the compressive strengths of NSC and CLSM would decrease. However, when incorporating 5% GFRP waste into CLSM, the compressive strength was 7% higher than concrete without GFRP. However, the workability of CLSM could be improved to meet engineering standards by adding an appropriate amount of superplasticizer. This finding suggests that the use of various combinations of proportions in the mixture during production could allow for the production of CLSM with different compressive strength needs. In addition, the use of recycled thermoset GFRP waste as a new aggregate replacement for traditional aggregates in CLSM was found to be a more sustainable alternative to the current CLSM combinations used in the market.
Experimental Study on Ultrasonic Assisted Turning of GH4068 Superalloy
Authors: Kang Renke , Zhang Pengnan , Wei Zhaocheng , Dong Zhigang , Wang Yidan
Published: May 2023

GH4068 superalloy is a new type of nickel-based superalloy in the aerospace field. It is an important alloy material for the manufacture of aircraft tubular components and aero-engine hot-end components. These components need to be machined with good surface quality to meet their use requirements. New hybrid machining processes can improve the quality of surface finish compared to conventional machines. In this paper, ultrasonic assisted turning (UAT) technology was applied to the machining of GH4068 superalloy. The experimental system of UAT was established. Experiments of UAT and conventional turning (CT) of GH4068 superalloy were carried out to study the effects of cutting speed, feed speed, cutting depth and vibration amplitude on cutting force and surface roughness. The surface morphology of the workpiece and chip were observed. The experimental results show that Fx and Fy can be reduced by a maximum of 44% and 63%, respectively, and the surface roughness can be reduced by a maximum of 31% after adding ultrasonic vibration. Compared with CT, the UAT has a better machining quality, a more obvious chip-breaking effect, and a smaller chip bending radius, which guides the high-quality processing of the GH4068 superalloy.
Comparison of Continuous and Pulsating Water Jet during Piercing of Ductile Material
Authors: Nag Akash , Srivastava Madhulika , Petrů Jana , Váňová Petra , Srivastava Ashish Kumar , Hloch Sergej
Published: May 2023

More efficient ways to process materials are constantly being sought, even in the case of continuous water flow technology, which acts on materials mainly by stagnant pressure. An alternative method is an ultrasound-stimulated pulsating water jet, the basis of which is the repeated use of impact pressure, which reduces the time interval for mechanical relaxation. This article focuses on a comparative study from the point of view of water mass flow rate on material penetration and its integrity. Relatively low pressures (p = 20, 30, and 40 MPa) with varying nozzle diameters (d = 0.4 and 0.6 mm) were used to identify the effectiveness of the pulsating water jet. The time exposure of the jet at a fixed place was varied from t = 0.5 to 5 s for each experimental condition. The results showed that with an increase in the pressure and diameter values, the disintegration depth increased. In addition, the surface topography and morphology images showed signs of ductile erosion in the form of erosion pits, upheaved surfaces, and crater formation. The microhardness study showed an increase of 10% subsurface microhardness after the action of the pulsating water jet as compared to the original material.
A Dynamic Analysis of Smart and Nanomaterials for New Approaches to Structural Control and Health Monitoring
Authors: Altabey Wael A. , Noori Mohammad
Published: May 2023

During recent years, remarkable progress has been made in the development of new materials [...]
Ultrafast Infrared Laser Crystallization of Amorphous Si/Ge Multilayer Structures
Authors: Bulgakov Alexander V. , Beránek Jiří , Volodin Vladimir A. , Cheng Yuzhu , Levy Yoann , Nagisetty Siva S. , Zukerstein Martin , Popov Alexander A. , Bulgakova Nadezhda M.
Published: May 2023

Silicon–germanium multilayer structures consisting of alternating Si and Ge amorphous nanolayers were annealed by ultrashort laser pulses at near-infrared (1030 nm) and mid-infrared (1500 nm) wavelengths. In this paper, we investigate the effects of the type of substrate (Si or glass), and the number of laser pulses (single-shot and multi-shot regimes) on the crystallization of the layers. Based on structural Raman spectroscopy analysis, several annealing regimes were revealed depending on laser fluence, including partial or complete crystallization of the components and formation of solid Si–Ge alloys. Conditions for selective crystallization of germanium when Si remains amorphous and there is no intermixing between the Si and Ge layers were found. Femtosecond mid-IR laser annealing appeared to be particularly favorable for such selective crystallization. Similar crystallization regimes were observed for both single-shot and multi-shot conditions, although at lower fluences and with a lower selectivity in the latter case. A theoretical analysis was carried out based on the laser energy absorption mechanisms, thermal stresses, and non-thermal effects.
Highly Efficient NO2 Sensors Based on Al-ZnOHF under UV Assistance
Authors: Yao Xingyu , Wang Rutao , Wu Lili , Song Haixiang , Zhao Jinbo , Liu Fei , Fu Kaili , Wang Zhou , Wang Fenglong , Liu Jiurong
Published: May 2023

Zinc hydroxyfluoride (ZnOHF) is a newly found resistive semiconductor used as a gas-sensing material with excellent selectivity to NO2 because of its unique energy band structure. In this paper, Al3+ doping and UV radiation were used to further improve the gas-sensing performance of ZnOHF. The optimized 0.5 at.% Al-ZnOHF sample exhibits improved sensitivity to 10 ppm NO2 at a lower temperature (100 °C) under UV assistance, as well as a short response/recovery time (35 s/96 s). The gas-sensing mechanism demonstrates that Al3+ doping increases electron concentration and promotes electron transfer of the nanorods by reducing the bandgap of ZnOHF, and the photogenerated electrons and holes with high activity under UV irradiation provide new reaction routes in the gas adsorption and desorption process, effectively promoting the gas-sensing process. The synergistic effect of Al3+ and UV radiation contribute to the enhanced performance of Al-ZnOHF.
Effect of Sodium Gluconate on Properties and Microstructure of Ultra-High-Performance Concrete (UHPC)
Authors: Wu Yonghua , Yuan Yibing , Niu Mengdie , Kuang Yufeng
Published: May 2023

The properties of concrete can be significantly affected by sodium gluconate (SG) at very small dosages. In this paper, the effects of SG on the fluidity, setting time, heat of hydration, and strength of ultra-high-performance concrete (UHPC) were studied. The results show that (1) in the plastic stage, SG inhibited the formation of early ettringite (AFt) and delayed the hydration of tricalcium silicate (C3S) and dicalcium silicate (C2S). SG increased the initial fluidity of UHPC without decreasing within 1 h. When the SG dosage was ≥0.06%, the slumps at 30 min and 60 min increased slightly. (2) In the setting hardening stage, the addition of SG inhibited the formation of calcium hydroxide (CH), which significantly extended the setting time of UHPC. When the dosage of SG was 0.15%, the initial and final setting times were 5.0 times and 4.5 times that of the blank group, respectively. SG had no obvious effect on the hydration rate of cement in the accelerated period, but the peak hydration temperature of UHPC was increased when the SG dosage was 0.03~0.12%. (3) In the strength development stage, the 1 d and 3 d strength of UHPC decreased significantly with the increase in the SG dosage. However, SG could promote the formation of AFt at the pores and aggregate interface in the later stage, reduce the porosity of cementite, and improve the compressive strength of UHPC in 28 d, 60 d, and 90 d. When the SG dosage was 0.12%, the 90d strength increased by 13%.
Effect of an External Magnetic Field on the Hydrogen Reduction of Magnetite Nanoparticles in a Polymer Matrix
Authors: Chernavskii Petr , Ozkan Sveta , Karpacheva Galina , Pankina Galina , Perov Nikolai
Published: May 2023

A hybrid electromagnetic nanomaterial, which is a matrix based on a conjugated polymer of poly-3-amine-7-methylamine-2-methylphenazine with dispersed magnetite nanoparticles immobilized on multi-walled carbon nanotubes, has been synthesized. In situ magnetometry was used to study the kinetics of the hydrogen reduction of Fe3O4 immobilized in the structure of a ternary nanocomposite in magnetic fields of different intensities. An increase in the magnetite reduction reaction rate with the formation of metallic iron nanoparticles at T=420∘C and at a magnetic field strength in the range of 60–3000 Oe was observed. The dependence of the degree of conversion of Fe3O4 on the magnetic field strength was established.
Finite-Time Adaptive Fuzzy Control for Unmodeled Dynamical Systems with Actuator Faults
Authors: Liu Ruixia , Xing Lei , Deng Hong , Zhong Weichao
Published: May 2023

This article concentrates upon the issue of finite-time tracking control for a category of nonlinear systems in pure-feedback form with actuator faults and unmodeled dynamics, where the loss of effectiveness and bias fault are considered. Meanwhile, the function approximation method utilizing fuzzy logic systems and dynamic surface control approach with first-order filter are implemented to model the unknown nonlinear terms induced from the proposed controller procedure and tackle the “explosion of complexity” issue of the classic backstepping method. The use of the maximal norm of the weight vector estimation method and adaptive approach reduces the computation load induced by fuzzy logic systems. Within the framework of backstepping control, a finite-time adaptive fuzzy fault-tolerant control protocol is derived to guarantee the boundedness of all signals and tracking error of the controlled system within a finite-time. Simulation studies are offered to show the validity of the derived theoretical results of the finite-time control protocol.
Correction: Ali et al. A Feature Selection Based on Improved Artificial Hummingbird Algorithm Using Random Opposition-Based Learning for Solving Waste Classification Problem. Mathematics 2022, 10, 2675
Authors: Ali Mona A. S. , P. P. Fathimathul Rajeena , Salama Abd Elminaam Diaa
Published: May 2023

Additional Affiliation(s) [...]
Three-Dimensional Lidar Localization and Mapping with Loop-Closure Detection Based on Dense Depth Information
Authors: Yang Liang , Yu Zhenbiao , Deng Chunjian , Lai Guanyu
Published: May 2023

This paper presents a novel lidar SLAM system for localizing a mobile robot to build a map of the environment. To identify the unknown transform matrix, we design a new scan-matching approach, in which a point cloud segmentation algorithm is additionally integrated. Different from the traditional normal distribution transform algorithm for point cloud registration, our newly proposed one additionally incorporates a ground point remover and a point cloud segmentation method. By employing the point cloud segmentation algorithm to divide the point cloud space into different cells, the newly proposed algorithm can guarantee the continuity and convergence of the cost function. To tackle the recognition difficulties that the camera-based loop-closure detection heavily depends on the environment’s appearance, a depth-completion algorithm is introduced to fuse sensor data to ensure the robustness of the algorithm. Moreover, the bags of binary words (DBoW) are adopted to improve the image-matching quality. Finally, experimental results are presented to illustrate the effectiveness of the proposed system.
Impact of the Emergency Procedure Zone on Emergency Care
Authors: Lin I-Chen , Chiu Po-Wei , Lin Chih-Hao
Published: May 2023

Background: Emergency department (ED) overcrowding is a public health crisis that affects patient care quality. Space management in the ED can affect patient flow dynamics and clinical practice. We proposed a novel design of the “emergency procedure zone” (EPZ). The purpose of the EPZ was to provide an isolated area for clinical practice and procedure teaching, to ensure a secure area with adequate equipment and monitors, and safeguard patient privacy and safety. This study aimed to analyze the impact of the EPZ on procedural practice and patient flow dynamics. Methods: This study was conducted at the ED of a tertiary teaching hospital in Taiwan. Data were collected from 1 March 2019 to 31 August 2020 (pre-EPZ period) and from 1 November 2020 to 30 April 2022 (post-EPZ period). Statistical analyses were performed using IBM SPSS Statistics software. This study focused on the number of procedures and length of stay in the emergency department (LOS-ED). Variables were analyzed using the chi-square test and Mann–Whitney U test. Statistical significance was defined as p < 0.05. Results: There were 137,141 (pre-EPZ period) and 118,386 (post-EPZ period) ED visits recorded during this period. The post-EPZ period showed a significant increase in central venous catheter insertion, chest tube or pigtail placement, arthrocentesis, lumbar puncture, and incision and drainage procedures (p < 0.001). For patients who were directly discharged from the ED, the post-EPZ period also had a higher percentage of ultrasound studies performed in the ED and a shorter LOS-ED for patients who were directly discharged from the ED (p < 0.001). Conclusions: The establishment of an EPZ in the ED has a positive impact on procedural efficiency. The EPZ improved diagnosis and disposition efficiency, shortened the length of stay, and provided benefits such as improved management, patient privacy, and teaching opportunities.
A Facile and Surfactant-Free Electrochemical Synthesis of PtIr Nanocubes towards Ammonia Electro-Oxidation
Authors: Tang Yusu , Geng Dinglei , Cheng Zhihao , Han Xin , Han Liying , Zhang Jinfeng , Xia Dahai , Liu Jie
Published: May 2023

Noble metal Pt catalyst has been identified as excellent electrocatalysts for the ammonia oxidation reaction (AOR). However, Pt’s scarcity, expensiveness, and toxicity hinder its large-scale commercial application. Herein, we report a facile and surfactant-free electrochemical synthesis method for the production of PtIr nanocubes. The PtIr nanocubes were in situ synthesized on carbon paper, and no organic additives were used at any stage in the synthesis of the catalyst. The formation of PtIr nanocubes was attributed to the synergy of the electro-adsorption/desorption of O-containing species and the preferential adsorption of hydrogen adatoms on PtIr(100) with a lower surface free energy. The obtained PtIr nanocubes exhibit an outstanding specific activity (SA) value of 1.34 mA cm−2, which is 1.5 and 3.8 times higher than Pt nanocubes (0.90 mA cm−2) and PtIr nanospheres (0.35 mA cm−2), respectively. The enhanced SA of the PtIr nanocubes can be ascribed to the synergic effects of multiple factors, including the (100) sites of the PtIr nanocubes, the dehydrogenation ability of Ir with respect to ammonia molecules, the electronic effects, and the clean surface of the catalyst due to the use of a “green” synthesis method. This work provides an effective strategy for the “green” synthesis of high-efficiency Pt-based metal catalysts with controllable shapes.
Novel Approach to Prepare Magnesium and Mg-Al Alloy from Magnesia by Using the Closed Microwave Aluminothermic Method
Authors: Zhang Teng , Wang Miao , Niu Libin , Zhang Jumei , Zhang Huihui , Zhang Mengchun
Published: May 2023

Herein, we report a novel approach to obtaining magnesium and nanocrystal Mg-Al alloy from magnesia using a closed microwave aluminothermic method in order to solve the problems of high energy consumption, high pollution, and low productivity in the process of magnesium and its alloy production. The main idea of the paper is to design a technique for the preparation of magnesium–aluminum alloy during the reduction process of MgO directly under atmospheric pressure. Based on this experimental idea, we have established a closed microwave aluminothermic reduction reactor. The great advantage of the reaction device is that it can make the reaction material heat up quickly to the reaction temperature in the microwave heating process and produce high-pressure magnesium vapor, which reacts with aluminum dramatically to form Mg-Al alloy under microwave irradiation. By the calculation of the electromagnetic field of the reaction device and sample using ANSYS electronics desktop 2018, the optimum microwave heating conditions for samples have been established. Based on the calculation results, we demonstrate that magnesium and its alloy are prepared successfully by using this method. In addition, the reduction rate of MgO is greatly improved, which is higher up to 79.97 Wt% when the reduction time is 30 min, at 1273 K, and the Mg2Al3 and MgAl alloy is formed during the reduction process as well. Moreover, the formation mechanism of Mg-Al alloy during the reduction process under microwave irradiation was discussed further. Our findings could provide a new approach, insights, and research directions to obtain magnesium and Mg-Al alloy directly from magnesia under normal pressure.
Ultrasonic Assisted Machining Overview: Accessing Feasibility and Overcoming Challenges for Milling Applications
Authors: Martins Henrique , Puga Hélder
Published: May 2023

Machinability, along with its associated facets, is a critical parameter that ultimately determines the cost of machining. Its optimization, however, is inherently limited by the current technology. To surmount such limitations, novel alternative machining technologies, such as Ultrasonic Assisted Machining (UAM), have emerged. The present study introduces UAM, the technology’s underlying principles, and general considerations for vibration application (harmonic waves, eigenfrequencies, resonance). The influence of ultrasonic application on the key parameters of conventional machining processes is studied and relevant research data are presented to support UAM benefits. Following, a comprehensive kinematic examination of vibration application to the milling process is conducted, accounting for various possible vibration modes. A detailed analysis of the requisite system components and their technical specifications is presented, followed by identifying common issues within such systems. Solutions for the identified limitations are proposed, acting as design guidelines for future technological advancements. Finally, based on the conducted research, conclusions are drawn and future directions for UAM are suggested.
Novel Cast and Wrought Al-3Zn-3Mg-3Cu-Zr-Y(Er) Alloys with Improved Heat Resistance
Authors: Glavatskikh Maria V. , Barkov Ruslan Yu. , Gorlov Leonid E. , Khomutov Maxim G. , Pozdniakov Andrey V.
Published: May 2023

The main weaknesses of commercial high-strength Al-Zn-Mg-Cu-based alloys are the low casting properties, corrosion and heat resistance. Al-Zn-Mg-Cu-based alloys with Zn/Mg ratio equal to 1 combine good strength, corrosion and heat resistance. Al alloys with atomic ratio Cu/Y(Er) equal to 4 have a narrow solidification range and high solidus temperature. Two basic principles were taken into consideration to develop novel heat-resistant Al-Zn-Mg-Cu-based alloys with improved casting properties: 1—mass ratio of Zn/Mg = 1, and 2—atomic ratio of Cu/Y(Er) = 4. The microstructure, phase transformation and tensile properties of the novel cast and wrought Al–3Zn–3Mg–3Cu–0.2Zr–Y(Er) alloys were investigated. The structure and phase composition were investigated via thermodynamic calculation, optical and scanning electron microscopy and X-ray diffraction methods. A two-step solution treatment with higher temperature in the second step provides a microstructure with better elongation, making possible to increase the hot rolling temperature of the Y or Er-containing alloys. The yield strength (YS) of the alloys decreased insignificantly from 270 to 290 MPa at room temperature to 225 to 260 MPa at 200 °C after casting, solution treatment, water quenching and aging. A better combination of the YS = 291–345 MPa and elongation (El.) (11–14.8%) was achieved in the Al3Zn3Mg3CuY and Al3Zn3Mg3CuEr alloys after solution treatment, rolling, recrystallization annealing, water quenching and aging compared with the Al3Zn3Mg3Cu alloy with YS = 245–340 MPa and El. = 6.8–12.5%.
Reorientation Mechanisms of Graphene Coated Copper {001} Surfaces
Authors: Song Jian , Yao Songsong , Li Quan , Ni Jiamiao , Yan Zhuoxin , Yang Kunming , Liu Guisen , Liu Yue , Wang Jian
Published: May 2023

Engineering the surface orientation of face-centered cubic (fcc) metals to the close-packed {111} plane can significantly enhance their oxidation resistance. However, owing to the synergetic effect of surface energy density (γ˙) and strain energy density (ω), such close-packed surface orientation can currently only be achieved by atomic-level thin film epitaxy or monocrystallization of polycrystalline metals. In this study, we characterized the microstructures of pure copper (Cu) foil and two types of graphene-coated Cu (Gr/Cu) foils and observed a 12~14 nm thick reconstructed surface layer with the {111} orientation in the high-temperature deposited Gr/{001} Cu surface. Combining the statistical results with thermodynamic analysis, we proposed a surface melting-solidification mechanism for the reconstruction of the Cu surface from {001} orientation to {111} orientation. This process is dominated by Gr/Cu interfacial energy and is particularly promoted by high-temperature surface melting. We also validated such a mechanism by examining Cu surfaces coated by h-BN (hexagonal boron nitride) and amorphous carbon. Our findings suggest a possible strategy to enhance the surface properties of fcc metals via engineering surface crystallography.
Particle Size Distribution and Its Impacts on Ash Deposition and Radiative Transfer during Oxy-Combustion of Rice Husk–Natural Gas
Authors: Krishnamoorthy Gautham
Published: May 2023

Rice husk (RH) co-combustion with natural gas in highly oxygen-enriched concentrations presents a net carbon-negative energy production opportunity while minimizing flue gas recycling. However, recent experiments have shown enhanced ash deposition rates in oxygen-enriched conditions, with deposition/shedding also being dependent on the particle size distribution (PSD) of the parent RH fuel. To uncover the causative mechanisms behind these observations, add-on models for ash deposition/shedding and radiative properties were employed in computational fluid dynamics simulations. The combustion scenarios investigated encompassed two types of RH (US RH, Chinese RH) with widely varying ash contents (by % mass) and inlet fuel PSD with air and O2/CO2 (70/30 vol %, OXY70) as oxidizers. Utilizing the measured fly-ash PSDs near the deposit surface and modeling the particle viscosity accurately, particle kinetic-energy (PKE)-based capture and shedding criteria were identified as the keys to accurate deposition/shedding rate predictions. The OXY70 scenarios showed higher ash-capturing propensities due to their lower PKE. Conversely, higher erosion rates were predicted in the AIR firing scenarios. In addition, the radiative characteristics across all the scenarios were dominated by the gases and were not sensitive to the fly-ash PSD. Therefore, the higher particle concentrations in the OXY70 conditions did not negatively impact the heat extraction.
Assessment of Pharmaco-Technological Parameters of Solid Lipid Nanoparticles as Carriers for Sinapic Acid
Authors: Russo Stefano , Greco Giuliana , Sarpietro Maria Grazia
Published: May 2023

Sinapic acid, 3,5-dimethoxyl-4-hydroxycinnamic acid, belonging to the class of hydroxycinnamic acids, shows antioxidant, anti-inflammatory, anticancer, hepatoprotective, cardioprotective, renoprotective, neuroprotective, antidiabetic, anxiolytic, and antibacterial activity. The aim of this work was to incorporate sinapic acid into solid lipid nanoparticles in order to improve its bioavailability. SLNs were prepared using the hot high-speed homogenization method. The pharmaco-technological properties and thermotropic profile of SLNs encapsulated with sinapic acid, as well as their interaction with biomembrane models, were evaluated. SLNs showed promising physicochemical properties and encapsulation efficiency, as well as a desirable release profile; moreover, they facilitated the interaction of sinapic acid with a biomembrane model made of multilamellar vesicles. In conclusion, this formulation can be used in further studies to assess its suitability to improve sinapic acid activity.