bluuebunny/crossref_metadata_2025 huggingface dataset:
Computer-Aided Diagnosis of Pulmonary Nodules in Rheumatoid Arthritis
Authors: Mușetescu Anca Emanuela , Gherghina Florin Liviu , Florescu Lucian-Mihai , Streba Liliana , Ciurea Paulina Lucia , Florescu Alesandra , Gheonea Ioana Andreea
Published: November 2022

(1) Background: Rheumatoid arthritis (RA) is considered a systemic inflammatory pathology characterized by symmetric polyarthritis associated with extra-articular manifestations, such as lung disease. The purpose of the present study is to use CAD in the detection of rheumatoid pulmonary nodules. In addition, we aim to identify the characteristics and associations between clinical, laboratory and imaging data in patients with rheumatoid arthritis and lung nodules. (2) Methods: The study included a number of 42 patients diagnosed with rheumatoid arthritis according to the 2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) criteria, examined from January 2017 to November 2022 in the Departments of Rheumatology and Radiology and Medical Imaging of the University of Medicine and Pharmacy of Craiova. Medical records were reviewed. A retrospective blinded review of CT for biopsy-proven pulmonary nodules in RA using Veolity LungCAD software was performed (MeVis Medical Solutions AG, Bremen, Germany). Imaging was also reviewed by a senior radiologist. (3) Results: The interobserver agreement proved to be moderate (κ = 0.478) for the overall examined cases. CAD interpretation resulted in false positive results in the case of 12 lung nodules, whereas false negative results were reported in the case of 8 lung nodules. The mean time it took for the detection of lung nodules using CAD was 4.2 min per patient, whereas the detection of lung nodules by the radiologist was 8.1 min per patient. This resulted in a faster interpretation of lung CT scans, almost reducing the detection time by half (p < 0.001). (4) Conclusions: The CAD software is useful in identifying lung nodules, in shortening the interpretation time of the CT examination and also in aiding the radiologist in better assessing all the pulmonary lung nodules. However, the CAD software cannot replace the human eye yet due to the relative high rate of false positive and false negative results.
Evaluation of Surface Roughness, Tool Wear and Chip Morphology during Machining of Nickel-Based Alloy under Sustainable Hybrid Nanofluid-MQL Strategy
Authors: Makhesana Mayur A. , Patel Kaushik M. , Bagga Prashant J.
Published: November 2022

Nickel-based super alloys exhibit high strength, oxidation and corrosion resistance; however, the machining of these alloys is a challenge that can be overcome with effective cooling/lubrication techniques. The use of a minimum quantity lubrication (MQL) technique is limited to lower cutting parameters due to the tremendous heat produced during the machining of Inconel 718. Sustainable and eco-friendly machining of Inconel 718 can be attained using MQL and lubricants based on nanofluids because of their improved heat transfer capabilities. For that purpose, the performance of hybrid nanofluid-MQL is examined. In this novel study, graphene and hexagonal boron nitride (hBN) nanoparticles are reinforced with palm oil and delivered to the machining interface using an MQL setup. The machining experiments are performed under the conditions of dry, wet, MQL and MQL with graphene/hBN deposited in palm oil. The machining performance under selected cutting conditions is assessed by analyzing the surface roughness, tool wear, chip morphology and surface quality of the machined workpiece. A comparison of results showcased the effectiveness of hybrid nanofluid-MQL with improvement in surface finish, reduction in tool wear and favorable chip forms concerning all other machining conditions.
Finite Element Modelling of Wear Behaviors of Composite Laminated Structure
Authors: Abdellah Mohammed Y. , Hassan Mohamed K. , AlMalki Abdel-Aziz , Mohamed Ahmed F. , Backar Ahmed H.
Published: November 2022

Three different laminated composites are used in this study: carbon fiber, woven glass fiber, and glass-fiber-reinforced epoxy. The composite laminate structures were fabricated using the hand lay-up technique at room temperature. The laminates were reinforced with epoxy resin, carbon fibers (CFRP), woven glass fibers (GFRP-W), and random-orientation glass fibers (GFRP-R) to obtain laminates with eight layers. The wear test was performed using a pin-on-disc tribometer with five different loads of 10, 20, 30, 40, and 50 N at room temperature and a constant speed of 3 m/s. In addition, three different surfaces were lubricated: dry, with grease, and with oil. The effect of lubrication on the weight loss of the laminates was measured. The linear elastic finite element model FEM was derived to simulate the pin on the disc and the failure mode in shear mode for the case of dry lubrication. In addition, the FEM allows the friction force to be measured to determine the friction coefficient numerically. For validation, a simple analytical model based on the shear stress induced by the laminates at the interfaces was extracted to measure the friction coefficients. Tensile strength is a characteristic property that is very important for the purpose of material description from FEM and the analytical model. Therefore, it was determined experimentally with a simple tensile test. The results show that the wear rate is better with GFRP-R composites. Moreover, the wear rate with grease is lower than with oil or dry. The FEM showed that the coefficient of friction decreases with normal force to a minimum value of 0.02 for the case of 50 N normal force and for GFRP-R, while the maximum value of the coefficient of friction was 0.55 for CFRP at 10 N normal load and the FEM results were in good agreement with the analytically determined data.
The Tribo-Dynamics Performance of the Lubricated Piston Skirt–Cylinder System Considering the Cylinder Liner Vibration
Authors: Zhao Bo , Wang Shijun , Xiao Peng , Xu Lingji , Hu Xinqing , Si Xiancai , Liu Yonghui
Published: November 2022

The tribo-dynamics performance of the piston–cylinder system is affected by multiple physical fields. The current work presents a novel multiphysics coupling method to model and analyze the lubricated piston skirt–cylinder interface considering the cylinder liner vibration. This method is implemented by coupling multibody dynamics of the crank-connecting rod–piston–cylinder system, the heat transfer of the cylinder and piston, hydrodynamics lubrication on the skirt–cylinder interface, vibration of the cylinder liner, and thermal as well as elastic deformation in the piston–cylinder system together with rheological characteristics of lubricating oil. The proposed method is adopted into a four-stroke gasoline engine to predict its dynamics and tribological characteristics, with the purpose of revealing the influence of cylinder liner vibration on the tribo-dynamics implementation of the piston–cylinder system. The results indicate that increasing the stiffness and damping coefficient of the cylinder is beneficial to suppress the vibration of the system, but it has little effect on the tribological characteristics of the piston skirt–cylinder interface.
Morphology and Luminescence of Flexible Free-Standing ZnO/Zn Composite Films Grown by Vapor Transport Synthesis
Authors: Zadorozhnaya Ludmila A. , Tarasov Andrey P. , Volchkov Ivan S. , Muslimov Arsen E. , Kanevsky Vladimir M.
Published: November 2022

A method for fabricating flexible free-standing ZnO/Zn composite films from the vapor phase using a regular array of silicon microwhiskers as a substrate is presented. The structural and morphological peculiarities, as well as luminescent properties of the films, were studied. The films have a hybrid structure consisting of two main microlayers. The first layer is formed directly on the tops of Si whiskers and has a thickness up to 10 µm. This layer features a polycrystalline structure and well-developed surface morphology. The second layer, which makes up the front side of the films, is up to 100 µm thick and consists of large microcrystals. The films show good bending strength—in particular, resistance to repeated bending and twisting—which is provided by a zinc metallic part constituting the flexible carrier of the films. ZnO photoluminescence was observed from both surfaces of the films but with conspicuous spectral differences. In particular, a significant weakening of ZnO green luminescence (more than 10 times) at an almost constant intensity of UV near-band edge emission was found for the polycrystalline side of the films as compared to the microcrystalline side. A high degree of homogeneity of the luminescent properties of the films over their area was demonstrated. The results obtained emphasize the relevance of further studies of such ZnO structures—in particular, for application in flexible devices, sensors, photocatalysis and light generation.
A New Insight into the Mechanisms Underlying the Discoloration, Sorption, and Photodegradation of Methylene Blue Solutions with and without BNOx Nanocatalysts
Authors: Matveev Andrei T. , Varlamova Liubov A. , Konopatsky Anton S. , Leybo Denis V. , Volkov Ilia N. , Sorokin Pavel B. , Fang Xiaosheng , Shtansky Dmitry V.
Published: November 2022

Methylene blue (MB) is widely used as a test material in photodynamic therapy and photocatalysis. These applications require an accurate determination of the MB concentration as well as the factors affecting the temporal evolution of the MB concentration. Optical absorbance is the most common method used to estimate MB concentration. This paper presents a detailed study of the dependence of the optical absorbance of aqueous methylene blue (MB) solutions in a concentration range of 0.5 to 10 mg·L−1. The nonlinear behavior of optical absorbance as a function of MB concentration is described for the first time. A sharp change in optical absorption is observed in the range of MB concentrations from 3.33 to 4.00 mg·L−1. Based on the analysis of the absorption spectra, it is concluded that this is due to the formation of MB dimers and trimers in the specific concentration range. For the first time, a strong, thermally induced discoloration effect of the MB solution under the influence of visible and sunlight was revealed: the simultaneous illumination and heating of MB solutions from 20 to 80 °C leads to a twofold decrease in the MB concentration in the solution. Exposure to sunlight for 120 min at a temperature of 80 °C led to the discoloration of the MB solution by more than 80%. The thermally induced discoloration of MB solutions should be considered in photocatalytic experiments when tested solutions are not thermally stabilized and heated due to irradiation. We discuss whether MB is a suitable test material for photocatalytic experiments and consider this using the example of a new photocatalytic material—boron oxynitride (BNOx) nanoparticles—with 4.2 and 6.5 at.% of oxygen. It is shown that discoloration is a complex process and includes the following mechanisms: thermally induced MB photodegradation, MB absorption on BNOx NPs, self-sensitizing MB photooxidation, and photocatalytic MB degradation. Careful consideration of all these processes makes it possible to determine the photocatalytic contribution to the discoloration process when using MB as a test material. The photocatalytic activity of BNOx NPs containing 4.2 and 6.5 at.% of oxygen, estimated at ~440 μmol·g−1·h−1. The obtained results are discussed based on the results of DFT calculations considering the effect of MB sorption on its self-sensitizing photooxidation activity. A DFT analysis of the MB sorption capacity with BNOx NPs shows that surface oxygen defects prevent the sorption of MB molecules due to their planar orientation over the BNOx surface. To enhance the sorption capacity, surface oxygen defects should be eliminated.
Flexible and Polarization Independent Miniaturized Double-Band/Broadband Tunable Metamaterial Terahertz Filter
Authors: Esakkimuthu Manikandan , Jothinayagam Inbarani , Arumugam Karthigeyan , Pravin Sheena Christabel , Jewariya Mukesh
Published: November 2022

In this paper, the design of a double-band terahertz metamaterial filter with broadband characteristics using a single conducting layer is presented. The design uses a structured top metallic layer over a polyimide material. The proposed design has achieved broadband band-pass transmission characteristics at the resonances of 0.5 THz and 1.65 THz, respectively. The 3-dB bandwidths for these two resonances are 350 GHz and 700 GHz, respectively, which indicates that dual-band resonance with broadband transmission characteristics was obtained. The design has achieved the same transmission characteristics for two different orthogonal polarizations, which was confirmed using numerical simulation. The design was tested for a different angle of incidences and it was observed that this results in angle-independent transmission behavior. In addition, for obtaining tunable resonant behavior, the top conductor layer was replaced by graphene material and a silicon substrate was added below the polymer layer. By varying the Fermi level of graphene, modulation in amplitude and phase was observed in numerical simulation. The physical mechanism of double-band behavior was further confirmed by surface current distribution. The proposed design is simple to fabricate, compact, i.e., the size is λ0/8, and obtained dual-band/broadband operation.
Biocarbons Obtained from Fennel and Caraway Fruits as Adsorbents of Methyl Red Sodium Salt from Water System
Authors: Bazan-Wozniak Aleksandra , Paluch Dorota , Wolski Robert , Cielecka-Piontek Judyta , Nosal-Wiercińska Agnieszka , Pietrzak Robert
Published: November 2022

The aim of this study was to prepare biocarbons by biomass activation with carbon(IV) oxide. Fennel and caraway fruits were used as the precursors of bioadsorbents. The impact of the precursor type and temperature of activation on the physicochemical properties of the obtained biocarbons and their interaction with methyl red sodium salt upon adsorption process have been checked. The obtained bioadsorbents were characterized by determination of-low temperature nitrogen adsorption/desorption, elemental analysis, ash content, Boehm titration, and pH of water extracts. The biocarbons have surface area varying from 233–371 m2/g and basic in nature with acidic/basic oxygen-containing functional groups (3.23–5.08 mmol/g). The adsorption capacity varied from 63 to 141 mg/g. The influence of different parameters, such as the effectiveness of methyl red sodium salt adsorption, was evaluated. The adsorption kinetics was well fitted using a pseudo-second-order model. The Freundlich model best represented the equilibrium data. The amount of adsorbed dye was also found to increase with the increasing temperature of the process.
Mechanical Properties and Oxidation Behavior of TaWSiN Films
Authors: Tzeng Chin-Han , Chang Li-Chun , Chen Yung-I
Published: November 2022

This study explored the structural characteristics, mechanical properties, and oxidation behavior of W-enriched TaWSiN films prepared through co-sputtering. The atomic ratios [W/(W + Ta)] of the as-deposited films maintained a range of 0.77–0.81. The TaWSiN films with a Si content of 0–13 at.% were crystalline, whereas the film with 20 at.% Si was amorphous. The hardness and Young’s modulus of crystalline TaWSiN films maintained high levels of 26.5–29.9 GPa and 286–381 GPa, respectively, whereas the hardness and Young’s modulus of the amorphous Ta7W33Si20N40 films exhibited low levels of 18.2 and 229 GPa, respectively. The oxidation behavior of TaWSiN films was investigated after annealing at 600 °C in a 1%O2–Ar atmosphere, and cone-like Ta0.3W0.7O2.85 oxides formed and extruded from the TaWSiN films.
Analysis of Acousto-Optic Figure of Merit in KGW and KYW Crystals
Authors: Yushkov Konstantin B. , Naumenko Natalya F. , Molchanov Vladimir Ya.
Published: November 2022

Monoclinic potassium rare-earth crystals are known as efficient materials for solid-state lasers and acousto-optic modulators. A number of specific configurations for acousto-optic devices based on those crystals have recently been proposed, but the acousto-optic effect of those crystals has only been analyzed fragmentarily for some interaction directions. In this work, we numerically searched for the global maxima of an acousto-optic figure of merit for isotropic diffraction in KGd(WO4)2 and KY(WO4)2 crystals. It was demonstrated that the global maxima of the acousto-optic figure of merit in those crystals occur in the slow optical mode propagating along the crystal’s twofold symmetry axis and in the acoustic wave propagating orthogonally, both for quasi-longitudinal and quasi-shear acoustic modes. The proposed calculation method can be readily used for the optimization of the acousto-optic interaction geometry in crystals with arbitrary symmetry.
In Situ Observation of ZnO Nanoparticle Formation by a Combination of Time-Resolved X-ray Absorption Spectroscopy and X-ray Diffraction
Authors: Eckelt Franz , Rothweiler Patrick , Braun Frederic , Voss Lukas , Šarić Ankica , Vrankić Martina , Lützenkirchen-Hecht Dirk
Published: November 2022

The formation of ZnO nanomaterials from different Zn acetylacetonate precursor solutions was studied in situ by employing simultaneous, time-resolved X-ray diffraction (XRD) and X-ray absorption spectroscopy (EXAFS) at the Zn K-edge. The precursor solutions were heated from room temperature to the desired reaction temperatures in a hermetically sealed cell dedicated to X-ray experiments. In general, the first indications for the formation of hexagonal ZnO were found for elevated temperatures of about 80 °C both by XRD and EXAFS, and the contributions increase with temperature and time. However, no reaction intermediates could be proved in addition to the Zn precursors and the formed hexagonal ZnO materials. Furthermore, the results show that the efficiency of the reaction, i.e., the conversion of the precursor material to the ZnO product, strongly depends on the solvent used and the reaction temperature. ZnO formation is accelerated by an increased temperature of 165 °C and the use of 1-octanol, with a conversion to ZnO of more than 80% after only a ca. 35 min reaction time according to a detailed analysis of the EXAFS data. For comparison, an identical concentration of Zn acetylacetonate in water or dilute alkaline NaOH solutions and a reaction temperature of around 90 °C leads to a smaller conversion of approximately 50% only, even after several hours of reaction. The particle size determined from XRD for different orientations shows a preferred orientation along the c-direction of the hexagonal crystal system, as well in accordance with scanning electron microscopy. The LaMer model explained this highly non-uniform growth of needle-like ZnO crystallites.
The Effect of Tool Geometry on the Strength of FSW Aluminum Thin Sheets
Authors: Vairis Achilles , Petousis Markos , Mountakis Nikolaos , Tsarouchidou Charikleia , Vidakis Nectarios
Published: November 2022

Welding tools of different designs have been used to join friction stir welding 2-mm-thick Al 7075 sheets, to investigate the effect of the tool geometry on the weld performance. Five cylindrical tools with different pin geometries were manufactured from heat-treatable low alloy steel WNr 1.6582/DIN 34CrNiMo6. Additionally, the effect of the welding speed was considered in the work, with six different speeds ranging from 80 mm/min to 300 mm/min. The weld tool rotational speed was kept constant at 1000 rpm and all other parameters were also kept constant in the experiments. The tensile strength was measured to investigate the mechanical properties of the weld. Results were processed with statistical analysis tools, which showed that the mechanical strength was affected by tool geometry as well as welding speed. The weld tool with the highest pin diameter achieved the highest tensile strength. The welding speed affected the tensile strength differently in the different weld tool geometries studied. The highest weld efficiency reported in the tests is 72.20%, achieved with a cylindrical pin weld tool at 250 mm/min.
Synthesis, Characteristics, and Effect of Zinc Oxide and Silver Nanoparticles on the In Vitro Regeneration and Biochemical Profile of Chrysanthemum Adventitious Shoots
Authors: Tymoszuk Alicja , Sławkowska Natalia , Szałaj Urszula , Kulus Dariusz , Antkowiak Małgorzata , Wojnarowicz Jacek
Published: November 2022

Studies on nanoparticles’ effects on plants are relevant for horticulture. This study aimed to test the influence of zinc oxide submicron particles (ZnO SMPs), zinc oxide nanoparticles (ZnO NPs), and zinc oxide nanoparticles combined with silver nanoparticles (ZnO+1%Ag NPs) applied at 100 and 500 mg·L−1 on the regeneration and biochemical activity of adventitious shoots in Chrysanthemum × morifolium (Ramat.) Hemsl. ‘UTP Burgundy Gold’ and ‘UTP Pinky Gold’. The original microwave solvothermal synthesis and characteristics of the ZnO samples were described. Internodes were cultured on the MS medium with 0.6 mg∙L−1 6-benzylaminopurine (BAP) and 2 mg∙L−1 indole-3-acetic acid (IAA). In ‘UTP Burgundy Gold’, the highest shoot regeneration efficiency was obtained for 100 mg·L−1 ZnO SMPs and 500 mg·L−1 ZnO NPs treatments (6.50 and 10.33 shoots per explant, respectively). These shoots had high or moderate chlorophyll and carotenoid contents. In ‘UTP Pinky Gold’, the highest shoot number was produced in the control (12.92), for 500 mg·L−1 ZnO SMPs (12.08) and 500 mg·L−1 ZnO NPs (10.42). These shoots had increased chlorophyll (a+b)-to-carotenoid ratios. In ‘UTP Pinky Gold’, the ZnO SMPs and ZnO NPs affected the anthocyanins biosynthesis, whereas ZnO + 1%Ag NPs decreased the phenolics accumulation. These results are important for the improvement of chrysanthemum micropropagation.
Direct Metal Laser Sintering of the Ti6Al4V Alloy from a Powder Blend
Authors: Ramosena Lekhetho Ambition , Dzogbewu Thywill Cephas , du Preez Willie
Published: November 2022

Additively manufactured Ti6Al4V parts have only seen major application in industries such as the aerospace and medical industries, mainly due to the high cost of production of the feedstock powder. In this article, the feasibility of in situ alloying a powder blend of elemental Ti and an Al–V master alloy to produce the Ti6Al4V alloy through direct metal laser sintering is presented and discussed. In a previous study, single track formation from this powder blend was studied and analyzed to determine the optimum principal process parameters suitable for this powder blend. These process parameters were employed in this study to produce single and double layers where the effects of varied hatch distance and the employment of a rescanning strategy on the surface morphology and alloy homogeneity were investigated. Lastly, in the current study, three-dimensional specimens were produced and analyzed to determine the alloy microstructure, homogeneity, part porosity and mechanical properties. The analyses revealed that a Ti6Al4V alloy with a density of up to 99.9% and corresponding tensile strength and ductility values of up to 942.9 MPa and 17% was produced. Furthermore, a minimum Al evaporation value of 7.2% was recorded. Therefore, in situ alloying can indeed be employed to produce high-quality Ti6Al4V parts from an elemental Ti and an Al–V master alloy powder blend.
Aging Characterizations of Modified Asphalt Binders Based on Low Field Nuclear Magnetic Resonance (LF-NMR)
Authors: Wang Lili , Li Xinsheng , Shen Junan , Li Jing , Wang Wei
Published: November 2022

Styrene-butadiene-styrene block copolymer (SBS) and crumb rubber modifier (CRM) are commonly used modifiers to modify asphalt binders. The aging of modified asphalt binders is an important factor affecting their performance. In this paper, the effects of the two modifiers (i.e., SBS, CRM) on the aging of modified asphalt binders were studied by using low field nuclear magnetic resonance (LF-NMR) technology and dynamic shear rheological (DSR) tests. Test results showed that when T2, a parameter of relaxation time from NMR test, was within 2.2 milliseconds, the relaxation peak of both modified and unmodified asphalt binders tested showed two peaks (i.e., “M” shape), and when it was greater than 2 milliseconds, extra peaks appeared only in the modified asphalts. These extra peaks gradually disappeared with increased aging; the modifiers carried signal intensities of their own. The addition of a modifier changes the law of “the greater the viscosity of asphalt, the shorter the T2 relaxation time”. With the aging process, the normalized peak area (NPA) from NMR decreased, and rutting resistance factor from DSR increased. However, the NPA of modified asphalt increased after the PAV test, which may be related to the change of H semaphore. The rheological properties of the asphalt binders before and after aging were well-correlated with the NPA of T2.
Active Control Method for Rotor Eccentric Vibration of High-Speed Motor Based on Least Squares Support Vector Machine
Authors: Wang Liheng , Zhuang Ming , Yuan Kai
Published: November 2022

Aiming at the problems of large active control errors and long control times in the active control method for high-speed motor rotor eccentric vibration, an active control method for high-speed motor rotor eccentric vibration based on a least squares support vector machine was proposed. Firstly, the overall structure of the system and its high-speed rotor were designed. Secondly, by calculating the centrifugal force of the eccentric rotor, the vibration of the relative phase of the rotor position, and the width of the air gap between the rotor and the stator, a mathematical model of the eccentric vibration of the high-speed motor rotor was established. Then, the basic principle of the least squares support vector machine was analyzed, and the control parameters of the eccentric vibration of the high-speed motor rotor were set and filtered. Finally, an active control model of high-speed motor rotor eccentric vibration was constructed, and the optimal solution of the model was obtained by regression algorithm. The experimental results show that the method is effective for the active control of high-speed motor rotor eccentric vibration, the control effect is consistent with the ideal effect, and the control time is short—the longest is only 0.13 s.
Preference and Stability Regions for Semi-Implicit Composition Schemes
Authors: Fedoseev Petr , Karimov Artur , Legat Vincent , Butusov Denis
Published: November 2022

A numerical stability region is a valuable tool for estimating the practical applicability of numerical methods and comparing them in terms of stability. However, only a little information can be obtained from the stability regions when their shape is highly irregular. Such irregularity is inherent to many recently developed semi-implicit and semi-explicit methods. In this paper, we introduce a new tool for analyzing numerical methods called preference regions. This allows us to compare various methods and choose the appropriate stepsize for their practical implementation, such as stability regions, but imposes stricter conditions on the methods, and therefore is more accurate. We present a thorough stability and preference region analysis for a new class of composition methods recently proposed by F. Casas and A. Escorihuela-Tomàs. We explicitly show how preference regions, plotted for an arbitrary numerical integration method, complement the conventional stability analysis and offer better insights into the practical applicability of the method.
High-Enthalpy Geothermal Simulation with Continuous Localization in Physics
Authors: Wang Yang , Voskov Denis
Published: November 2022

Simulation of heat production in high-enthalpy geothermal systems is associated with a complex physical process in which cold water invades steam-saturated control volumes. The fully implicit, fully coupled numerical strategy is commonly adopted to solve the governing system composed of mass and energy conservation equations. A conventional nonlinear solver is generally challenged by the strong nonlinearity present during phase transition because of a huge contrast of thermodynamics between hot steam and cool water. In the process of solution, due to the steam condensation, the reduction in fluid volume reduces the pressure in the control volume. This generates multiple local minima in the physical parameter space, which indicates the Newton initial guess should be carefully selected to guarantee the nonlinear convergence. Otherwise, the Newton iteration will approach a local minimum and the solution based on Newton’s update cannot converge and needs to be repeated for a smaller timestep. This problem brings simulation to the stalling behavior where a nonlinear solver wastes a lot of computations and performs at a very small timestep. To tackle this problem, we formulated continuous localization of Newton’s method based on an Operator-Based Linearization (OBL) approach. In OBL, the physical space can be parameterized in terms of operators with supporting points at different levels of resolution. During the simulation, the operator values at supporting points are obtained through reference physics and the remaining part of the space is interpolated. In this way, the nonlinear physical parameter space can be flexibly characterized with different degrees of accuracy. In our proposed approach, the nonlinear Newton iterations are performed in parameter space with different resolutions from coarse to fine. Specifically, the Newton solution under coarser resolution is taken as the initial guess for that under finer resolution. A coarser parameter space represents more linear physics, under which the nonlinear solver quickly converges to a localized solution near the true solution. With refinement in physics, the Newton iteration will approach the true solution and the stalling behaviour in the simulation is avoided. Therefore, a larger timestep can be utilized in the simulation compared with the conventional nonlinear solvers.
A Hybrid Delay Aware Clustered Routing Approach Using Aquila Optimizer and Firefly Algorithm in Internet of Things
Authors: Hosseinzadeh Mehdi , Ionescu-Feleaga Liliana , Ionescu Bogdan-Ștefan , Sadrishojaei Mahyar , Kazemian Faeze , Rahmani Amir Masoud , Khan Faheem
Published: November 2022

Protocols for clustering and routing in the Internet of Things ecosystem should consider minimizing power consumption. Existing approaches to cluster-based routing issues in the Internet of Things environment often face the challenge of uneven power consumption. This study created a clustering method utilising swarm intelligence to obtain a more even distribution of cluster heads. In this work, a firefly optimization method and an aquila optimizer algorithm are devised to select the intermediate and cluster head nodes required for routing in accordance with the NP-Hard nature of clustered routing. The effectiveness of this hybrid clustering and routing approach has been evaluated concerning the following metrics: remaining energy, mean distances, number of hops, and node balance. For assessing Internet of things platforms, metrics like network throughput and the number of the living node are crucial, as these systems rely on battery-operated equipment to regularly capture environment data and transmit specimens to a base station. Proving effective, the suggested technique has been found to improve system energy usage by at least 18% and increase the packet delivery ratio by at least 25%.
A New Zero-Inflated Negative Binomial Multilevel Model for Forecasting the Demand of Disaster Relief Supplies in the State of Sao Paulo, Brazil
Authors: Yale Camila Pareja , Yoshizaki Hugo Tsugunobu Yoshida , Fávero Luiz Paulo
Published: November 2022

This article presents the results of the implementation of a forecasting model, to predict the relief materials needed for assisting in decisions prior to natural disasters, thus filling a gap in the exploration of Generalized Linear Mixed Models (GLMM) in a humanitarian context. Demand information from the State of Sao Paulo, Brazil was used to develop the Zero Inflated Negative Binomial Multilevel (ZINBM) model, which gets to handle the excess of zeros in the count data and considers the nested structure of the data set. Strategies for selecting predictor variables were based on the understanding of the needs for relief supplies; consequently, they were derived from vulnerability indicators, demographic factors, and occurrences of climatic anomalies. The model presents coefficients that are statistically significant, and the results show the importance of considering the nested structure of the data and the zero-inflated nature of the outcome variable. To validate the fitness of the ZINBM model, it was compared against the Poisson, Negative Binomial (NB), Zero Inflated Poisson (ZIP), and Zero Inflated Negative Binomial (ZINB) models.
Wavelet Density and Regression Estimators for Continuous Time Functional Stationary and Ergodic Processes
Authors: Didi Sultana , Bouzebda Salim
Published: November 2022

In this study, we look at the wavelet basis for the nonparametric estimation of density and regression functions for continuous functional stationary processes in Hilbert space. The mean integrated squared error for a small subset is established. We employ a martingale approach to obtain the asymptotic properties of these wavelet estimators. These findings are established under rather broad assumptions. All we assume about the data is that they are ergodic, but beyond that, we make no assumptions. In this paper, the mean integrated squared error findings in the independence or mixing setting were generalized to the ergodic setting. The theoretical results presented in this study are (or will be) valuable resources for various cutting-edge functional data analysis applications. Applications include conditional distribution, conditional quantile, entropy, and curve discrimination.
Throughput Optimization for NOMA Cognitive Relay Network with RF Energy Harvesting Based on Improved Bat Algorithm
Authors: Luo Yi , Wu Chenyang , Leng Yi , Huang Nüshan , Mao Lingxi , Tang Junhao
Published: November 2022

Due to the shortcomings of the standard bat algorithm (BA) for multi-parameter optimization, an improved bat algorithm is proposed. The benchmark function test shows that the proposed algorithm has better realization of high-dimensional function optimization by introducing multiple flight modes, adopting adaptive strategy based on group trend, and employing loudness mutation flight selection strategy based on Brownian motion. Aiming at the characteristics of complex networks structure and multiple design variables of energy harvesting non-orthogonal multiple access cognitive relay networks (EH-NOMA-CRNs), we utilize the proposed hybrid strategy improved bat algorithm (HSIBA) to optimize the performance of EH-NOMA-CRNs. At first, we construct a novel two-hop underlay power beacon assisted EH-NOMA-CRN, and derive the closed-form expressions of secondary network’s outage probability and throughput. Then, the secondary network performance optimization is formulated as the throughput maximation problem with regard to EH ratio and power allocation factors. Subsequently, the HSIBA is employed to optimize the above parameters. Numerical results show that the proposed HSIBA can achieve optimization to the constructed EH-NOMA-CRN with faster convergence speed and higher stability.
Artificial Intelligence-Based Prediction of Crude Oil Prices Using Multiple Features under the Effect of Russia–Ukraine War and COVID-19 Pandemic
Authors: Jahanshahi Hadi , Uzun Süleyman , Kaçar Sezgin , Yao Qijia , Alassafi Madini O.
Published: November 2022

The effect of the COVID-19 pandemic on crude oil prices just faded; at this moment, the Russia–Ukraine war brought a new crisis. In this paper, a new application is developed that predicts the change in crude oil prices by incorporating these two global effects. Unlike most existing studies, this work uses a dataset that involves data collected over twenty-two years and contains seven different features, such as crude oil opening, closing, intraday highest value, and intraday lowest value. This work applies cross-validation to predict the crude oil prices by using machine learning algorithms (support vector machine, linear regression, and rain forest) and deep learning algorithms (long short-term memory and bidirectional long short-term memory). The results obtained by machine learning and deep learning algorithms are compared. Lastly, the high-performance estimation can be achieved in this work with the average mean absolute error value over 0.3786.
Mathematical Properties of a Novel Graph-Theoretic Irregularity Index with Potential Applicability in QSPR Modeling
Authors: Hayat Sakander , Arif Amina , Zada Laiq , Khan Asad , Zhong Yubin
Published: November 2022

Irregularity indices are graph-theoretic parameters designed to quantify the irregularity in a graph. In this paper, we study the practical applicability of irregularity indices in QSPR modeling of the physicochemical and quantum-theoretic properties of compounds. Our comparative testing shows that the recently introduced IRA index has significant priority in applicability over other irregularity indices. In particular, we show that the correlation potential of the IRA index with certain physicochemical and quantum-theoretic properties such as the enthalpy of formation, boiling point, and π-electron energies is significant. Our QSPR modeling suggests that the regression models with the aforementioned characteristics such as strong curve fitting are, in fact, linear. Considering this the motivation, the IRA index was studied further, and we provide analytically explicit expressions of the IRA index for certain graph operations and compositions. We conclude the paper by reporting the conclusions, implications, limitations, and future scope of the current study.
Effects of Alcohol Consumption on Oxidative Stress in a Sample of Patients Recruited in a Dietary Center in a Southern University Hospital: A Retrospective Study
Authors: Metro Daniela , Corallo Francesco , Fedele Francesco , Buda Martina , Manasseri Luigi , Buono Viviana Lo , Quartarone Angelo , Bonanno Lilla
Published: November 2022

Background and objectives: The aim of this retrospective study was to evaluate the effects of alcohol consumption on oxidative stress. Materials and Methods: The study was conducted by analyzing the increase in lipid peroxidation, the reduction of antioxidant defenses and the alteration of the oxidation/antioxidant balance after the administration of ethanol in 25% aqueous solution (v/v) at a concentration of 0.76 g/kg of body weight daily in two doses for 3 days. The changes in oxidative stress indices were investigated by standard methods previously described. Results: Ethanol administration has determined a significant increase in plasma levels of lipid hydroperoxide (LOOH), malonilaldehyde (MDA) and oxidized glutathione (GSSH), and a decrease in total antioxidant capacity (TAC), reduced glutathione (GSH) and GSH/GSSH ratio. Conclusions: In the proposed experimental condition, the excessive and repeated consumption of ethanol causes oxidative damage, as shown by the increase in lipid peroxidation, the reduction of antioxidant defenses and the alteration of the oxidation/antioxidant balance, which, at least in part, are responsible for the harmful effects of excess ethanol.
Assessing Whether Morphological Changes in Axillary Lymph Node Have Already Occurred Prior to Metastasis in Breast Cancer Patients by Ultrasound
Authors: Guo Qiang , Dong Zhiwu , Jiang Lixin , Zhang Lei , Li Ziyao , Wang Dongmo
Published: November 2022

Background and Objectives: Whether the morphological changes in axillary lymph node (ALN) have occurred prior to metastasis remains unclear in breast cancer (BC) patients. The aim of this study is to investigate the influence of BC for the morphology of non-metastasis ALN (N−) and, further, to improve the performance of ultrasound (US) examination for metastasis ALN (N+). Materials and Methods: In this retrospective study, 653 patients with breast mass were enrolled and divided into normal group of 202 patients with benign breast tumor, N− group of 233 BC patients with negative ALN and N+ group of 218 BC patients with positive ALN. US features of ALN were evaluated and analyzed according to long (L) and short (S) diameter, the (L/S) axis ratio, cortical thickness, lymph node edge, replaced hilum and color Doppler flow imaging (CDFI). Results: ALN US features of short diameter, replaced hilum, cortical thickness and CDFI have significant statistical differences in N− group comparing with normal group and N+ group, respectively (p < 0.05). Conclusions: Therefore, BC can affect ALN and lead to US morphological changes whether lymph node metastasis is present, which reduces the sensitivity of axillary US. The combination of US and other examination methods should be applied to improve the diagnostic performance of N+.
Atrial Fibrillation and Transvenous Lead Extraction—A Comprehensive Subgroup Analysis of the GermAn Laser Lead Extraction RegistrY (GALLERY)
Authors: Chung Da-Un , Pecha Simon , Burger Heiko , Anwar Omar , Eickholt Christian , Nägele Herbert , Reichenspurner Hermann , Gessler Nele , Willems Stephan , Butter Christian , Hakmi Samer
Published: November 2022

Background: Atrial fibrillation is the most common arrhythmia and has been described as driver of cardiovascular morbidity and risk factor for cardiac device-related complications, as well as in transvenous lead extraction (TLE). Objectives: Aim of this study was to characterize the procedural outcome and risk-factors of patients with atrial fibrillation (AF) undergoing TLE. Methods: We performed a subgroup analysis of all AF patients in the GALLERY (GermAn Laser Lead Extraction RegistrY) database. Predictors for all-cause mortality were assessed. Results: A total number of 510 patients with AF were identified with a mean age of 74.0 ± 10.3 years. Systemic infection (38.4%) was the leading cause for TLE, followed by local infection (37.5%) and lead dysfunction (20.4%). Most of the patients (45.9%) presented with pacemaker systems to be extracted. The total number of leads was 1181 with a 2.3 ± 0.96 leads/patient. Clinical procedural success was achieved in 97.1%. Occurrence of major complications was 1.8% with a procedure-related mortality of 1.0%. All-cause mortality was high with 5.9% and septic shock being the most common cause. Systemic device infection (OR: 49.73; 95% CI: 6.56–377.09, p < 0.001), chronic kidney disease (CKD; OR: 2.67; 95% CI: 1.01–7.03, p = 0.048) and a body mass index < 21 kg/m2 (OR: 6.6; 95% CI: 1.68–25.87, p = 0.007) were identified as independent predictors for all-cause mortality. Conclusions: TLE in AF patients is effective and safe, but in patients with systemic infection the mortality due to septic shock is high. Systemic infection, CKD and body mass index <21 kg/m2 are risk factors for death in patient with AF undergoing TLE.
Improved Hydrolytic and Mechanical Stability of Sulfonated Aromatic Proton Exchange Membranes Reinforced by Electrospun PPSU Fibers
Authors: Pasquini Luca , Sauvan Maxime , Narducci Riccardo , Sgreccia Emanuela , Knauth Philippe , Di Vona Maria Luisa
Published: November 2022

The hydrolytic stability of ionomer membranes is a matter of concern for the long-term durability of energy storage and conversion devices. Various reinforcement strategies exist for the improvement of the performances of the overall membrane. We propose in this article the stabilization of membranes based on aromatic ion conducting polymers (SPEEK and SPPSU) by the introduction of an electrospun mat of inexpensive PPSU polymer. Characterization data from hydrolytic stability (mass uptake and dimension change) and from mechanical and conductivity measurements show an improved stability of membranes in phosphate buffer, used for enzymatic fuel cells, and in distilled water. The synergistic effect of the reinforcement, together with the casting solvent and the thermal treatment or blending polymers, is promising for the realization of high stability ionomer membranes.
Revealing the Origin of Heterogeneous Phase Transition and Deformation Behavior in Au-Ag-Cu-Based Multicomponent Alloys
Authors: Zhang Boning , Fu Li , Ge Hualong , Rong Xuequan , Xiong Kai , He Junjie , Mao Yong
Published: November 2022

Local chemical heterogeneity of highly-concentrated multicomponent alloys has drawn much attention as it can produce novel material behaviors and remarkable properties. In Au-Ag-Cu-based multicomponent alloys, phase separation and ordering have long been recognized to correlate with grain boundaries (GBs), but there is still a lack of atomic-scale understanding of the heterogeneous phase transition and how the microstructures respond to deformation. In this paper, a joint experimental and theoretical study was conducted on a medium-entropy polycrystalline model alloy, which is a representative Au-Ag-Cu-based multicomponent alloy with important applications in fields such as photocatalyst and micro-/nano-electromechanical systems. The GB regions are observed to preferentially nucleate two-phase lamellar structures, which are softer than grain interiors featuring short-range-order and modulated morphologies. First-principles calculations suggest the GB segregation of Ag and depletion of Cu are energetically favorable, consequently creating compositions that facilitate phase separation and impede ordering. Calculations of elasticity-based mechanical properties, stacking fault and surface energies reveal the GB lamellar structures are intrinsically soft with heterogeneous deformation capabilities. Furthermore, design strategies based on GB segregation engineering and tuning the dual-phase compositions are proposed to control heterogeneities. The results provide new insights into GB segregation, phase nucleation precursor and mechanical properties of noble-metal multicomponent alloys.
Effects of Build Orientations on Microstructure Evolution, Porosity Formation, and Mechanical Performance of Selective Laser Melted 17-4 PH Stainless Steel
Authors: Aripin Mohammad Azlan , Sajuri Zainuddin , Jamadon Nashrah Hani , Baghdadi Amir Hossein , Syarif Junaidi , Mohamed Intan Fadhlina , Aziz Ahmad Muhammad
Published: November 2022

In this study, the effect of phase, microstructure, and porosity in Selective Laser Melting (SLM) on hardness, tensile, and fracture behavior of 17-4 PH was investigated. The increasing interest in SLM in producing complex parts has encouraged the industry to produce performance parts, such as martensitic 17-4 PH stainless steel. However, the microstructure and mechanical behavior of SLM 17-4PH is not fully understood by researchers. Understanding the microstructure profile is complex because it is driven by thermal history and porosity. Both elements vary, based on the build directions, further hindering researchers from fully understanding the mechanical properties. To fabricate specimens in three different building orientations (0°, 45°, and 90°), 17-4 powder was used. Two phases, namely, austenite and martensite, with 90° build direction, retained more austenite, due to the reheating process on a smaller base area. The optical microstructure revealed several elements that were distinct for SLM processing, including circular, columnar lath, wave melt pool, and porosity. Columnar lath was found to grow continuously across different melt pools. Hardness was found to be higher for 0° than for 90°, due to higher martensite content. Tensile strength was highest for 0°, at 958 MPa, higher than at 45° and 90° at 743 and 614 MPa, respectively. Porosity analysis validated that 90° had all three types of porosities and, specifically, the crescent type, which held un-melted powders. All types of porosities were found in fractography analysis.