bluuebunny/crossref_metadata_2025 huggingface dataset:
Shake Table Testing of Voltage and Current Transformers and Numerical Derivation of Corresponding Fragility Curves
Authors: Cavalieri Francesco , Donelli Giuseppe , Pinho Rui , Dacarro Filippo , Bernardo Nunzia , de Nigris Michele
Published: December 2022

Damage to devices installed in electric substations, which have shown vulnerable behaviour under strong earthquakes in the last decades, may endanger power delivery in the emergency phases during and after an earthquake. Within seismic risk assessment of power networks, the definition of the fragility functions of electric equipment is paramount. However, in the current literature the availability of such fragility models for some specific electric substation components, including instrument transformers, is relatively limited, this being the reason behind the deployment of the current experimental and numerical research endeavour. Two voltage transformers and two current transformers having different system voltage levels (respectively in the high voltage HV and extra-high voltage EHV ranges) were subjected to shake table tests, and the experimental results were used to calibrate the corresponding 3D numerical models developed in OpenSees. A number of nonlinear dynamic analyses carried out within a multiple-stripe analysis (MSA) framework allowed the derivation of 16 fragility curves for the four transformers in both stand-alone and elevated/supported configurations, considering also two different soil types. Based on the derived curves, one of the voltage transformers is expected to experience light or negligible damage due to earthquake shaking, owing to its high resonance frequencies (and hence stiffness), whilst the remaining three devices may suffer moderate damage under medium to strong shaking intensities; however, their seismic risk is in effect mitigated by the presence of the typically employed supporting column. Comparison against models available in the literature lent valuable reassurance on the adequacy of the employed methodology and the reliability of the derived fragility curves.
Effects of Home-Based Electrical Stimulation on Plasma Cytokines Profile, Redox Biomarkers, and Metalloproteinases in the Heart Failure with Reduced Ejection Fraction: A Randomized Trial
Authors: da Silva Marianne Lucena , de Sousa Neto Ivo Vieira , de Lima Alexandra C. G. B. , Barin Fabrício , de Toledo Nóbrega Otávio , de Cássia Marqueti Rita , Cipriano Graziella F. B. , Durigan João Luiz Quagliotti , Ferreira Eduardo Antônio , Bottaro Martim , Arena Ross , Cahalin Larry P. , Neder José Alberto , Junior Gerson Cipriano
Published: December 2022

Background: Low-frequency electrical stimulation (LFES) is an adjuvant method for heart failure (HF) patients with restrictions to start an exercise. However, the impact on molecular changes in circulating is unknown. We investigated the effects of 10 weeks of home-based LFES on plasma cytokines profile, redox biomarkers, metalloproteinases (MMPs) activity, and exercise performance in HF patients. Methods: Twenty-four HF patients (52.45 ± 9.15 years) with reduced ejection fraction (HFrEF) (EF < 40%), were randomly assigned to a home-based LFES or sham protocol. Plasma cytokines profile was assessed through interleukins, interferon-gamma, and tumor necrosis factor levels. Oxidative stress was evaluated through ferric reducing antioxidant power, thiobarbituric acid-reactive substances, and inducible nitric oxide synthase. The MMPs activity were analyzed by zymography. Cardiorespiratory capacity and muscle strength were evaluated by cardiopulmonary test and isokinetic. Results: LFES was able to increase the active-MMP2 activity post compared to pre-training (0.057 to 0.163, p = 0.0001), while it decreased the active-MMP9 (0.135 to 0.093, p = 0.02). However, it did not elicit changes in cytokines, redox biomarkers, or exercise performance (p > 0.05). Conclusion: LFES protocol is a promising intervention to modulate MMPs activity in HFrEF patients, although with limited functional effects. These preliminary responses may help the muscle to adapt to future mechanical demands dynamically.
Color-Coded Hydrogen: Production and Storage in Maritime Sector
Authors: Panić Ivan , Cuculić Aleksandar , Ćelić Jasmin
Published: December 2022

To reduce pollution from ships in coastal and international navigation, shipping companies are turning to various technological solutions, mostly based on electrification and the use of alternative fuels with a lower carbon footprint. One of the alternatives to traditional diesel fuel is the use of hydrogen as a fuel or hydrogen fuel cells as a power source. Their application on ships is still in the experimental phase and is limited to smaller ships, which serve as a kind of platform for evaluating the applicability of different technological solutions. However, the use of hydrogen on a large scale as a primary energy source on coastal and ocean-going vessels also requires an infrastructure for the production and safe storage of hydrogen. This paper provides an overview of color-based hydrogen classification as one of the main methods for describing hydrogen types based on currently available production technologies, as well as the principles and safety aspects of hydrogen storage. The advantages and disadvantages of the production technologies with respect to their application in the maritime sector are discussed. Problems and obstacles that must be overcome for the successful use of hydrogen as a fuel on ships are also identified. The issues presented can be used to determine long-term indicators of the global warming potential of using hydrogen as a fuel in the shipping industry and to select an appropriate cost-effective and environmentally sustainable production and storage method in light of the technological capabilities and resources of a particular area.
Improved Ship Object Detection in Low-Illumination Environments Using RetinaMFANet
Authors: Ma Ruixin , Bao Kexin , Yin Yong
Published: December 2022

Video-based ship object detection has long been a popular research issue that has received attention in the water transportation industry. However, in low-illumination environments, such as at night or in fog, the water environment has a complex variety of light sources, video surveillance images are often accompanied by noise, and information on the details of objects in images is worsened. These problems cause high rates of false detection and missed detection when performing object detection for ships in low-illumination environments. Thus, this paper takes the detection of ship objects in low-illumination environments at night as the research object. The technical difficulties faced by object detection algorithms in low-illumination environments are analyzed, and a dataset of ship images is constructed by collecting images of ships (in the Nanjing section of Yangtze River in China) in low-illumination environments. In view of the outstanding performance of the RetinaNet model in general object detection, a new multiscale feature fusion network structure for a feature extraction module is proposed based on the same network architecture, in such a way that the extraction of more potential feature information from low-illumination images can be realized. In line with the feature detection network, the regression and classification detection network for anchor boxes is improved by means of the attention mechanism, guiding the network structure in the detection of object features. Moreover, the design and optimization of the augmentation of multiple random images and prior bounding boxes in the training process are also carried out. Finally, on the basis of experimental validation analysis, the optimized detection model was able to improve ship detection accuracy by 3.7% with a limited decrease in FPS (frames per second), and has better results in application.
Effects of Different Orthoses on Neuromuscular Activity of Superficial and Deep Shoulder Muscles during Activities of Daily Living and Physiotherapeutic Exercises in Healthy Participants
Authors: Grim Casper , Baumgart Christian , Schlarmann Manuel , Hotfiel Thilo , Javanmardi Sasha , Hoffmann Natalie , Kurz Eduard , Freiwald Jürgen , Engelhardt Martin , Hoppe Matthias W.
Published: December 2022

Background: This study aimed to investigate the effects of different shoulder orthoses on the neuromuscular activity of superficial and deep shoulder muscles during activities of daily living (ADL) and physiotherapeutic exercises. Methods: Ten participants with healthy shoulders (31 ± 3 years, 23.1 ± 3.8 kg/m2) were randomized to receive a “shoulder sling”, an “abduction pillow” and a “variably adjustable orthosis” on the dominant side. With each orthosis, they completed seven ADL with and four physiotherapeutic exercises without wearing the orthoses. An electromyographic system was used to record the neuromuscular activity of three superficial (trapezius, deltoid, pectoralis major) and two deep shoulder muscles (infraspinatus, supraspinatus) using surface and intramuscular fine-wire electrodes. Results: The neuromuscular activity differs between the orthoses during ADL (p ≤ 0.045), whereby the “variably adjustable orthosis” mostly showed the highest activation levels associated with the worst subjective wearing comfort rated on a visual analog scale. In addition, differences exist between the physiotherapeutic exercises (p ≤ 0.006) demonstrating the highest activations of the infra- and supraspinatus muscles for assistive elevation and wipe across a table, middle for pendulum and lowest for continuous passive motion exercises. Conclusions: The neuromuscular activity of superficial and deep shoulder muscles differs between the orthoses during ADL and also between the physiotherapeutic exercises.
A Dynamic Evaluation Method of Urban Ecological Networks Combining Graphab and the FLUS Model
Authors: Li Hao , Chen Hongyu , Wu Minghao , Zhou Kai , Zhang Xiang , Liu Zhicheng
Published: December 2022

Rapid urbanization has led to landscape fragmentation and habitat loss. As an organic structure integrating green space, an urban ecological network can effectively reduce ecological risks and protect biodiversity if its landscape connectivity is maintained. Chaoyang District in Beijing is facing the challenge of transformational development due to excessive urbanization. Taking this district as the study area, this study assessed the environmental impact of different development scenarios on landscape connectivity indices and explored the most relevant strategies for important green space patches by combining ecological network modeling (Graphab) and scenario simulation techniques (FLUS model). The results show that under the urban expansion scenario, the probability of connectivity (PC) decreases by 59.7%, while under the master plan scenario, it increases by 102.1%. Even under the ideal ecological scenario, the ecological network structure of the region faces structural problems. Patches and corridors with high delta probabilities of connectivity (dPC) are concentrated in the north, with no effective connection between the north and south. Finally, planning strategies and priorities for important patches under different urban development goals are proposed through a strategy matrix. Overall, this study proposes a framework for decision-makers to solve planning conflicts between urban expansion and biodiversity conservation, especially for cities in transition.
Investigation of Volumetric Block Proportion (VBP) Effect on Excavation-Induced Ground Response of Talus-like Rock Mass Based on DEM Simulations
Authors: Wang Shuaifeng , Yi Yinlian , Li Xiaochang , Zhang Shaoqiang , Zhang Zixin
Published: December 2022

Due to the complexity of the talus-like rock mass with different values of volumetric block proportion (VPB), it is thus crucial to explore the VBP effect on the excavation-induced ground responses. We conduct a series of 2D DEM (discrete element method) simulations on a common circular tunnel excavation in the talus-like rock mass with different VBPs (0%, 15%, 50%, 85% and 100%). For each VBP, two support scenarios, i.e., unsupported and supported by a rigid lining, are considered. The micro characteristics of the excavation-induced ground responses, including the contact force, force chain, coordination number and shear-slip contact, and the stress distribution and ground settlement are elaborated in detail. Accordingly, three types of talus-like rock masses are identified as soil-, hybrid- and rock-types, corresponding to VBP = 0–15%, 50%, and 85–100%, respectively. It is found that the lining support is essential for maintaining the ground stability of a tunnel excavation in the soil- and hybrid-type talus-like rock masses while the backbones formed by rock blocks in the rock-type talus-like rock mass can provide a certain support for the surrounding ground. Our findings have important implications for optimizing the construction scheme of tunnel excavation in different types of talus-like rock masses.
Scattering Analysis of AlGaN/AlN/GaN Heterostructures with Fe-Doped GaN Buffer
Authors: Arteev Dmitri S. , Sakharov Alexei V. , Lundin Wsevolod V. , Zavarin Evgenii E. , Nikolaev Andrey E. , Tsatsulnikov Andrey F. , Ustinov Viktor M.
Published: December 2022

The results of the study of the influence of Fe segregation into the unintentionally doped GaN channel layer in AlGaN/AlN/GaN heterostructures with Fe-doped GaN buffer layer on the electrical properties of two-dimensional electron gas are presented. A set of several samples was grown by metal-organic vapor-phase epitaxy and characterized by the van der Pauw method. The dependence of concentration and mobility of the two-dimensional electron gas on the channel layer thickness was analyzed theoretically by self-consistent solving of 1D Poisson and Schrödinger equations and scattering rate calculations within the momentum relaxation time approximation. It was found that both concentration and mobility decreases were responsible for the increase in the sheet resistance in the structures with a thinner channel layer, with a drop in mobility being not only due to ionized impurity scattering, but also due to a combined effect of weakening of screening, lower carrier energy and change in form-factors on scattering by interface roughness, dislocations and polar optical phonons.
Decoration of Ultramicrotome-Cut Polymers with Silver Nanoparticles: Effect of Post-Deposition Laser Treatment
Authors: Kaimlová Markéta , Pryjmaková Jana , Šlouf Miroslav , Lyutakov Oleksiy , Ceccio Giovanni , Vacík Jiří , Siegel Jakub
Published: December 2022

Today, ultramicrotome cutting is a practical tool, which is frequently applied in the preparation of thin polymeric films. One of the advantages of such a technique is the decrease in surface roughness, which enables an effective recording of further morphological changes of polymeric surfaces during their processing. In view of this, we report on ultramicrotome-cut polymers (PET, PEEK) modified by a KrF excimer laser with simultaneous decoration by AgNPs. The samples were immersed into AgNP colloid, in which they were exposed to polarized laser light. As a result, both polymers changed their surface morphology while simultaneously being decorated with AgNPs. KrF laser irradiation of the samples resulted in the formation of ripple-like structures on the surface of PET and worm-like ones in the case of PEEK. Both polymers were homogeneously covered by AgNPs. The selected area of the samples was then irradiated by a violet semiconductor laser from the confocal laser scanning microscope with direct control of the irradiated area. Various techniques, such as AFM, FEGSEM, and CLSM were used to visualize the irradiated area. After irradiation, the reverse pyramid was formed for both types of polymers. PET samples exhibited thicker transparent reverse pyramids, whereas PEEK samples showed thinner brownish ones. We believe that his technique can be effectively used for direct polymer writing or the preparation of stimuli-responsive nanoporous membranes.
Laser Directed Energy Deposition of an AlMgScZr-Alloy in High-Speed Process Regimes
Authors: Zhao Tong , Chen Teng , Wang Yuhan , Wang Mengjie , Bakir Maha , Dahmen Marius , Cai Wangcan , Hong Chen , Schopphoven Thomas , Pirch Norbert , Brucki Matthias , Gasser Andres , Häfner Constantin Leon
Published: December 2022

Aluminum-magnesium-scandium-zirconium (AlMgScZr) alloys need to be rapidly cooled from the liquid state to obtain a high degree of solute supersaturation that helps to exploit the precipitation hardening potential of the material. While AlMgScZr alloys have been successfully used in laser powder bed fusion (LPBF) processes, there has been little research in the field of laser directed energy deposition (DED) of the material. The limited previous studies have shown that the performance of AlMgScZr parts fabricated with DED only reached about 60% of that of the parts fabricated with LPBF. In view of breaking through the limitation associated with the process conditions of conventional DED, this work demonstrates the DED of AlMgScZr alloys in high-speed process regimes and elucidates the mechanism of enhancing the hardness and tensile strength of AlMgScZr alloys by increasing the cooling rate by one to two orders of magnitudes, as well as reducing the track overlapping and the porosity of the specimens during the process. A maximum average hardness of nearly 150 HV0.1 and a max. tensile strength of 407 MPa are obtained by using an energy per unit length of 5400 J/m and a powder feed rate per unit length of 0.25 g/m.
Prediction Model of VCA Formed by the Packing of Hybrid Lithological Coarse Aggregates Used in SMA
Authors: Jiang Weiliang , Liu Long , Cao Weidong , Yang Shanglei , Liu Shutang , Li Jingchen
Published: December 2022

The voids in coarse aggregate (VCA) is an important volumetric index in the mineral aggregate gradation design of stone matrix asphalt (SMA) mixtures. To explore the law of variation for VCA formed by the packing of basalt and lime coarse aggregates, a uniform design method and vibrating compaction tests were used to establish the prediction model. Based on the test results and stepwise regression analysis, a reliable prediction model of VCA was obtained. There is a multiple nonlinear relationship between the VCA and the proportion of each coarse aggregate in the mixture. Regardless of the type of coarse aggregates used, the rule of VCA with different forms of aggregate gradation curves has universal significance. This conclusion can help to determine the aggregate gradation in the design of SMA mixtures.
Flammability of Polymer Compositions Filled with Wheat Bran
Authors: Sasimowski Emil , Samujło Bronisław , Grochowicz Marta , Majewski Łukasz
Published: December 2022

The article presents the results of flammability tests on polymer compositions with wheat bran (WB) as the applied filler, and polyethylene (PE) or poly(butylene succinate) (PBS) as the matrix material. Tests were conducted using samples of compositions containing 10, 30 and 50%wt wheat bran. The test samples were manufactured by injection moulding from compositions previously produced by extrusion pelleting. For comparative purposes, samples made only of the plastics used for the composition matrix were also examined. Flammability tests were carried out in accordance with the recommendations of EN 60695-11-10 Part 11–10 with horizontal and vertical positioning of the sample, using a universal flammability-test-stand. During the flammability tests, changes in the temperature field in the area of the burning sample were also recorded, using a thermal imaging camera. Sample residues after flammability tests were also examined with infrared spectroscopy (FTIR) to assess their thermal destruction. The results of the study showed a significant increase in flammability with bran content for both PE and PBS matrix compositions. Clear differences were also found in the combustion behaviour of the matrix materials alone. Both the burning rate and maximum flame temperature were lower in favour of PBS. PBS compositions with wheat bran also showed lower flammability, compared with their PE matrix counterparts.
Fabrication of CuYO2 Nanofibers by Electrospinning and Applied to Hydrogen Harvest
Authors: Hsu Kai-Chun , Keyan Arjunan Karthi , Hung Chin-Wei , Sakthinathan Subramanian , Yu Chung-Lun , Chiu Te-Wei , Nagaraj Karuppiah , Fan Fang-Yu , Shan Yung-Kang , Chen Po-Chou
Published: December 2022

Hydrogen can be employed as an alternative renewable energy source in response to climate change, global warming, and the energy problem. Methanol gas steam reforming (SRM) is the major method used in industry to produce hydrogen. In the SRM process, the catalyst nature offers benefits such as low cost, simplicity, and quickness. In this work, delafossite copper yttrium oxide (CuYO2) nanofibers were successfully prepared by electrospinning. The prepared CuYO2 nanofibers have different physical and chemical properties including thermoelectric behavior. The electrospinning method was used to produce as-spun fibers and annealed in an air atmosphere to form Cu2Y2O5 fibers; then, Cu2Y2O5 fibers were annealed in a nitrogen atmosphere to form CuYO2 nanofibers. X-ray diffraction studies and thermogravimetric and transmission electron microscope analysis confirmed the formation of CuYO2 nanofibers. The CuYO2 nanofibers were applied to methanol steam reforming for hydrogen production to confirm their catalytic ability. The CuYO2 nanofibers exhibited high catalytic activity and the best hydrogen production rate of 1967.89 mL min−1 g-cat−1 at 500 °C. The highly specific surface area of CuYO2 nanofibers used in steam reforming reactions could have significant economic and industrial implications. The performance of these CuYO2 nanofibers in hydrogen generation could be very important in industries with a global economic impact. Furthermore, the H2 production performance increases at higher reaction temperatures.
Adhesion of Modified Epoxy Resin to a Concrete Surface
Authors: Szewczak Andrzej , Łagód Grzegorz
Published: December 2022

The protection of building elements exposed to the weather using hydrocarbon-based agents is a comprehensive group of analyses. These agents are characterized by very high chemical resistance, waterproofness, as well as adhesion to surfaces made of various materials, i.e., concrete, steel, ceramics and wood. Modification of adhesion, which ultimately leads to an increase in the durability of a protective/face coating made of such a material, can lead to a longer life of these layers and a less frequent need for replacement or restoration. The following paper describes an experimental research program on the possibility of increasing the adhesion and durability of epoxy resin modified with the use of powder fillers. The resin can be used as a protective or top coat on the surface of concretes or mortars. The main objective of the study was to increase the adhesion of the resin to the concrete substrate, modified by grinding and sandblasting to increase the roughness. For the series studied, both the changes in physicochemical parameters, which determine how the resin penetrates the irregularities of the substrate and mechanical parameters, which mainly determine the durability of the layer made in this way, were identified. A modified version of the pull-off test was used as a method to directly evaluate the effectiveness of the modified resins.
Load Distribution and Dynamic Response in Torque Split Applications
Authors: Civan Süleyman Emre , Demir Cihan
Published: December 2022

This study consists of constructing and analyzing gear mathematical models of torque split systems for contact pressure distribution and dynamic transmission error at different gear positions concerning phase angles. According to the method specified in the AGMA 927 standard, load distribution is calculated by considering shaft torsion and bending deformations. Partial contact loss may occur as a result of shaft bending with asymmetric gear positioning on a long shaft. The contact separation can be decreased by reaction force balancing if the driven gears are in the opposite position with respect to the drive gear. In the calculation of the dynamic transmission error of the torque split model, a parametric phase difference for the gear positions is proposed using gear geometry parameters. The variation of the dynamic response according to the change in the parametric phase angle in the torque split system is analyzed for the same values of each gear. Small changes in the phase values change the system response significantly. To obtain lower dynamic transmission error amplitude, the phase difference and gear positions are examined. The contact pressure distribution is validated by the finite element method, and the dynamic transmission error is compared with the experimental study in the literature.
Stability Analysis of Buoyancy Magneto Flow of Hybrid Nanofluid through a Stretchable/Shrinkable Vertical Sheet Induced by a Micropolar Fluid Subject to Nonlinear Heat Sink/Source
Authors: Khan Umair , Zaib Aurang , Ishak Anuar , Alotaibi Abeer M. , Eldin Sayed M. , Akkurt Nevzat , Waini Iskandar , Madhukesh Javali Kotresh
Published: December 2022

The utilization of hybrid nanofluids (HNs) to boost heat transfer is a promising area of study, and thus, numerous scientists, researchers, and academics have voiced their admiration and interest in this area. One of the main functions of nanofluids is their dynamic role in cooling small electrical devices such as microchips and associated gadgets. The major goal of this study is to perform an analysis of the buoyancy flow of a shrinking/stretching sheet, whilst considering the fascinating and practical uses of hybrid nanofluids. The influence of a nonlinear heat source/sink induced by a micropolar fluid is also inspected. Water-based alumina and copper nanoparticles are utilized to calculate the fine points of the fluid flow and the features of heat transfer. The governing equations are framed with acceptable assumptions and the required similarity transformations are used to turn the set of partial differential equations into ordinary differential equations. The bvp4c technique is used to solve the simplified equations. Dual solutions are presented for certain values of stretching/shrinking parameters as well as the mixed convective parameter. In addition, the shear stress coefficient in the first-branch solution (FBS) escalates and decelerates for the second-branch solution (SBS) with the superior impact of the magnetic parameter, the mass transpiration parameter, and the solid nanoparticles volume fraction, while the contrary behavior is seen in both (FB and SB) solutions for the larger values of the material parameter.
Oil Price Shocks to Foreign Assets and Liabilities in Saudi Arabia under Pegged Exchange Rate
Authors: Samargandi Nahla , Sohag Kazi
Published: December 2022

The Saudi economy ought to maintain a significant amount of foreign exchange reserves due to the pegged exchange rate regime. As a hydrocarbon economy, we measure the dynamic response of external assets and liabilities of banks to the international oil price in Saudi Arabia. In the presence of extreme observations, we apply sophisticated frameworks, including cross-quantilograms, quantile-on-quantile and TVP-VAR approaches, to analyze weekly time-series data from 1993 to 2021. Our results from the cross-quantilogram and quantile-on-quantile frameworks demonstrate that foreign assets and liabilities responded asymmetrically to the volatilities of international oil prices under the bullish and bearish states of the market over different memories. The TVP-VAR results indicate that, during the COVID-19 pandemic, the Saudi economy encountered negative net foreign assets, which occurred mainly as a significant plague of international oil prices. Our findings are robust under different estimators.
Almost Generalized Derivation on Banach Algebras
Authors: Bae Jae-Hyeong , Chang Ick-Soon , Kim Hark-Mahn
Published: December 2022

We take into consideration generalized derivations. First, we study the stability of generalized derivations on Banach algebras under consideration. Then we prove some theorems involving approximate generalized derivations on Banach algebras. These results can be applied to C*-algebras.
Global Stability of Delayed SARS-CoV-2 and HTLV-I Coinfection Models within a Host
Authors: Elaiw Ahmed M. , Shflot Abdulsalam S. , Hobiny Aatef D.
Published: December 2022

The aim of the present paper is to formulate two new mathematical models to describe the co-dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human T-cell lymphotropic virus type-I (HTLV-I) in a host. The models characterizes the interplaying between seven compartments, uninfected ECs, latently SARS-CoV-2-infected ECs, actively SARS-CoV-2-infected ECs, free SARS-CoV-2 particles, uninfected CD4+T cells, latently HTLV-I-infected CD4+T cells and actively HTLV-I-infected CD4+T cells. The models incorporate five intracellular time delays: (i) two delays in the formation of latently SARS-CoV-2-infected ECs and latently HTLV-I-infected CD4+T cells, (ii) two delays in the reactivation of latently SARS-CoV-2-infected ECs and latently HTLV-I-infected CD4+T cells, and (iii) maturation delay of new SARS-CoV-2 virions. We consider discrete-time delays and distributed-time delays in the first and second models, respectively. We first investigate the properties of the model’s solutions, then we calculate all equilibria and study their global stability. The global asymptotic stability is examined by constructing Lyapunov functionals. The analytical findings are supported via numerical simulation. The impact of time delays on the coinfection progression is discussed. We found that, increasing time delays values can have an antiviral treatment-like impact. Our developed coinfection model can contribute to understand the SARS-CoV-2 and HTLV-I co-dynamics and help to select suitable treatment strategies for COVID-19 patients with HTLV-I.
Design and Experimental Verification of a General Single-Switch N-Stage Z-Network High Gain Boost Converter
Authors: Liu Xiaoyi , Yu Samson Shenglong , Zhang Guidong , Lin Weiqun , Liu Tao , Le Weiping
Published: December 2022

A single-switch N-stage Z-network high-gain boost converter is proposed in this study, which can be applied in the field of chip etching for bias provision. The circuit topology, operation mode, voltage gain and the control strategy are analyzed. Thereafter, the steady-state performance of the circuit is analyzed with small signal stability modeling. A simulation model is built using Simulink and compared with the traditional quadratic circuit. Combined with the control strategy, the circuit can obtain better steady-state performance by controlling the number of working N-networks and adjusting the duty ratio in the case of high voltage, wide range of voltage output and dynamic voltage output. The simulation model and hardware prototype of the single-switch four-stage Z-network high-gain boost circuit are built and tested, which have verified the effectiveness of the proposed design.
Advances in Singular and Degenerate PDEs
Authors: Fragapane Salvatore
Published: December 2022

This review was written with a dual purpose; on the one hand, to collect all the topics dealt with during the conference “Advances in Singular and Degenerate PDEs”. For this reason, in the first part of this work, the abstracts of the lectures during the workshop are shown. On the other hand, as well as the workshop, this work is a way to celebrate the career of Professor Maria Agostina Vivaldi. Professor Vivaldi’s long career and her work are hence highlighted in this work; moreover, some of the more recent results obtained by Professor Vivaldi about problems involving p-Laplace-type operators in fractal and pre-fractal boundary domains are here illustrated and discussed. In conclusion, some new recent outcomes and new perspectives are outlined.
Collaborative Screening of COVID-19-like Disease from Multi-Institutional Radiographs: A Federated Learning Approach
Authors: Abdel-Basset Mohamed , Hawash Hossam , Abouhawwash Mohamed
Published: December 2022

COVID-19-like pandemics are a major threat to the global health system have the potential to cause high mortality across age groups. The advance of the Internet of Medical Things (IoMT) technologies paves the way toward developing reliable solutions to combat these pandemics. Medical images (i.e., X-rays, computed tomography (CT)) provide an efficient tool for disease detection and diagnosis. The cost, time, and efforts for acquiring and annotating, for instance, large CT datasets make it complicated to obtain large numbers of samples from a single institution. However, owing to the necessity to preserve the privacy of patient data, it is challenging to build a centralized dataset from many institutions, especially during a pandemic. Moreover, heterogeneity between institutions presents a barrier to building efficient screening solutions. Thus, this paper presents a fog-based federated generative domain adaption framework (FGDA), where fog nodes aggregate patients’ data necessary to collaboratively train local deep-learning models for disease screening in medical images from different institutions. Local differential privacy is presented to protect the local gradients against attackers during the global model aggregation. In FGDA, the generative domain adaptation (DA) method is introduced to handle data discrepancies. Experimental evaluation on a case study of COVID-19 segmentation demonstrated the efficiency of FGDA over competing learning approaches with statistical significance.
Application of the ADMM Algorithm for a High-Dimensional Partially Linear Model
Authors: Feng Aifen , Chang Xiaogai , Shang Youlin , Fan Jingya
Published: December 2022

This paper focuses on a high-dimensional semi-parametric regression model in which a partially linear model is used for the parametric part and the B-spline basis function approach is used to estimate the unknown function for the non-parametric part. Within the framework of this model, the constrained least squares estimation is investigated, and the alternating-direction multiplier method (ADMM) is used to solve the model. The convergence is proved under certain conditions. Finally, numerical simulations are performed and applied to workers’ wage data from CPS85. The results show that the ADMM algorithm is very effective in solving high-dimensional partially linear models.
Microstructure and Properties of Press-Bonded Dissimilar Stainless Steel and Mild Carbon Steel Ingots
Authors: Huang Xuqiang , Lu Zhaoyang
Published: December 2022

Dissimilar steel welds between stainless and mild steels are necessary for the efficient utilization of stainless steels in construction. In the present work, a dissimilar large-sized steel ingot was fabricated by press bonding a Q235 steel to a SUS 304 steel at 1100–500 °C. The microstructure of bonded interfaces has been characterized by scanning electron microscopy, electron probe microanalysis, and transmission electron microscopy, together with tensile tests to evaluate the bonding strength. It has been demonstrated that a strong-bonded, high-quality, dissimilar steel ingot could be fabricated by press bonding. The (Fe, Cr)3C carbide is present in the narrow zone of diffusion-bonded stainless steel and mild steel. Interestingly, the maximum hardness is not too high to make the transition zone brittle but enough to constrain the narrow soft ferrite during tensile and fatigue tests, causing the final fracture to occur in the mild steel region rather than the bonding interface.
Duplex Stainless Steels for Thermal Energy Storage: Characterization of Oxide Scales Formed in Carbonate Salts at 500 °C
Authors: Morales Miguel , Gordon Sandra , Fernández-Arana Óscar , García-Marro Fernando , Mateo Antonio , Llanes Luis , Fargas Gemma
Published: December 2022

Next generation concentrated solar power (CSP) plants promise a higher operating temperature and better efficiency. However, new issues related to the corrosion against protection of the construction alloys need to be solved. In this work, two different duplex stainless steels grades, namely 2205 (DS2205) and 2507 (DS2507), were evaluated for their compatibility with the eutectic molten salt mixture of Li2CO3-K2CO3-Na2CO3 at 500 °C in air for thermal energy storage applications. Corrosion tests combined with complementary microscopy, microanalysis and mechanical techniques were employed to study the oxide scales formed on the surface of the duplex steels. The corrosion tests evidenced that the attack morphology in both duplex steels was a uniform oxidative process without localized corrosion. DS2507 presented a better corrosion resistance than DS2205, due to the formation of thinner, compact and continuous oxide layers with higher compositional content in Cr, Ni and Mo than DS2205. The oxide scales of DS2507 showed more remarkable mechanical integrity and adhesion to the metallic substrate.
Research on Wear Resistance of AISI 9310 Steel with Micro-Laser Shock Peening
Authors: Li Xianhao , Zhou Liucheng , Zhao Tianxiao , Pan Xinlei , Liu Ping
Published: December 2022

Improving the wear resistance of turbine engine drive components is crucial. This study presented a new Laser Shock Peening (LSP) technique: Micro-Laser Shock Peening (Micro-LSP) technology for surface modification and strengthening of AISI 9310 steel. The effects of different pulse energies (50 mJ, 150 mJ, 200 mJ) on surface morphology, mechanical properties, and wear behavior were investigated. The results showed that the Micro-LSP treatment reduced the wear rate by 56% to 74%. The dimpled structure induced during the strengthening process increased the surface roughness and reduced the contact area; moreover, the coefficient of friction (COF) was reduced. The treatment also had the effect of reducing the wear rate by collecting abrasive debris and changing some of the sliding wear into rolling wear. The reduced wear rate was a result of the combined effect of the dimpled structure and the hardened layer. In addition, a deeper hardened layer also slows down the onset of wear behavior. Micro-LSP technology offers completely new methods and possibilities for wear reduction.
A High-Sensitivity Bowel Sound Electronic Monitor Based on Piezoelectric Micromachined Ultrasonic Transducers
Authors: Ding Xiaoxia , Wu Zhipeng , Gao Mingze , Chen Minkan , Li Jiawei , Wu Tao , Lou Liang
Published: December 2022

Bowel sounds contain some important human physiological parameters which can reflect information about intestinal function. In this work, in order to realize real-time monitoring of bowel sounds, a portable and wearable bowel sound electronic monitor based on piezoelectric micromachined ultrasonic transducers (PMUTs) is proposed. This prototype consists of a sensing module to collect bowel sounds and a GUI (graphical user interface) based on LabVIEW to display real-time bowel sound signals. The sensing module is composed of four PMUTs connected in parallel and a signal conditioning circuit. The sensitivity, noise resolution, and non-linearity of the bowel sound monitor are measured in this work. The result indicates that the designed prototype has high sensitivity (−142.69 dB), high noise resolution (50 dB at 100 Hz), and small non-linearity. To demonstrate the characteristic of the designed electronic monitor, continuous bowel sound monitoring is performed using the electronic monitor and a stethoscope on a healthy human before and after a meal. Through comparing the experimental results and analyzing the signals in the time domain and frequency domain, this bowel sound monitor is demonstrated to record bowel sounds from the human intestine. This work displays the potential of the sensor for the daily monitoring of bowel sounds.
A Review of Converter Circuits for Ambient Micro Energy Harvesting
Authors: Lian Qian , Han Peiqing , Mei Niansong
Published: December 2022

The Internet of Things (IoT) has a great number of sensor nodes distributed in different environments, and the traditional approach uses batteries to power these nodes: however, the resultant huge cost of battery replacement means that the battery-powered approach is not the optimal solution. Micro energy harvesting offers the possibility of self-powered sensor nodes. This paper provides an overview of energy harvesting technology, and describes the methods for extracting energy from various sources, including photovoltaic, thermoelectric, piezoelectric, and RF; in addition, the characteristics of the four types of energy sources and the applicable circuit structures are summarized. This paper gives the pros and cons of the circuits, and future directions. The design challenges are the efficiency and size of the circuit. MPPT, as an important method of improving the system efficiency, is also highlighted and compared.
Heat Transfer Performance of Gel Foam Layer with Nanoparticles Doping under a Radiative Heat Flux
Authors: Zhou Rifeng , Cui Pengyu , Cheng Qingli , Lang Xuqing , Zhang Yong , Sun Qie , Du Mu
Published: December 2022

The risk of fire in the chemical industry’s production process is fatal. Gel foam has been widely employed in petroleum storage tanks, oil pools, and other petrochemical equipment for fire extinguishing and thermal protection. Recently, nanoparticles have been doped into gel foam to enhance thermal stability and insulation. However, heat transfer behaviors of the gel foam layer containing nanoparticles are still missing. In this study, a numerical heat transfer model of a gel foam layer containing silica nanoparticles under a radiative heat flux was established. Through simulation, the changes in foam thickness and temperature distribution were analyzed. The effects of the maximum heating temperature, initial gas content, nanoparticle size, and concentration on the thermal insulation behavior of the gel foam layer were systematically studied. The results showed that the thermal stability and insulation performance of the three-phase gel foam layer decreased with the increase in the initial gas content and particle size. Increasing the nanoparticle concentration could enhance the foam’s thermal stability and insulation performance. The results provide guidance for a designing gel foam with high thermal protection performance.
Study of Copper Electrodeposition at a Very Low Temperature near the Freezing Point of Electrolyte
Authors: Mo Yu , Shen Chunjian , Zhu Di
Published: December 2022

At or above room temperature, metal electrodeposits often feature coarse grains, uneven microstructure and high roughness with abnormal bulges. In this study, copper electrodeposits with abnormal properties were prepared in a sulfate bath at a low temperature near the freezing point of the electrolyte. The results showed that the average grain size of the copper featured an “increase-decrease” trend while decreasing the temperature form 5 °C to −5 °C, yielding a trend from 0.25 μm to 1 μm and then to 0.6 μm. In the early stage, the temperature does not change the three-dimensional continuous nucleation mode of deposited copper. When the nucleus density reaches saturation, the polarization caused by overpotential will act on the respective nucleation and crystal growth process twice, and finally exhibit a completely different trend than that at room temperature. This study may provide insights for breakthroughs in material properties from a temperature perspective.
Exploring the Diversity of Biofilm Formation by the Food Spoiler Brochothrix thermosphacta
Authors: Gaillac Antoine , Briandet Romain , Delahaye Elodie , Deschamps Julien , Vigneau Evelyne , Courcoux Philippe , Jaffrès Emmanuel , Prévost Hervé
Published: December 2022

Brochothrix thermosphacta is considered as a major spoiler of meat and seafood products. This study explores the biofilm formation ability and the biofilm structural diversity of 30 multi-origin B. thermosphacta strains using a set of complementary biofilm assays (biofilm ring test, crystal violet staining, and confocal laser scanning microscopy). Two major groups corresponding to low and high biofilm producers were identified. High biofilm producers presented flat architectures characterized by high surface coverage, high cell biovolume, and high surface area.
Investigating the Biocontrol Potential of the Natural Microbiota of the Apple Blossom
Authors: Schnyder Anya , Eberl Leo , Agnoli Kirsty
Published: December 2022

Erwinia amylovora, the causative agent of fire blight, leads to important economic losses of apple and pear crops worldwide. This study aimed to investigate the potential of the resident microbiota of the apple blossom in combatting plant disease-causing organisms, with a focus on controlling fire blight. We obtained 538 isolates from sites around Canton Zurich, which we tested for activity against Pectobacterium carotovorum and E. amylovora. We also evaluated the isolates’ activity against oomycete and fungal pathogens. Nine isolates showed activity against P. carotovorum, and eight of these against E. amylovora. Furthermore, 117 showed antifungal, and 161 anti-oomycete, activity. We assigned genera and in some cases species to 238 of the isolates by sequencing their 16S RNA-encoding gene. Five strains showed activity against all pathogens and were tested in a detached apple model for anti-E. amylovora activity. Of these five strains, two were able to antagonize E. amylovora, namely Bacillus velezensis #124 and Pantoea agglomerans #378. We sequenced the P. agglomerans #378 genome and analyzed it for secondary metabolite clusters using antiSMASH, revealing the presence of a putative bacteriocin cluster. We also showed that B. velezensis #124 exhibits strong activity against three different fungi and two oomycetes in vitro, suggesting a broader capacity for biocontrol. Our results showcase the protective potential of the natural apple blossom microbiota. We isolated two candidate biocontrol strains from apple blossoms, suggesting that they might persist at the most common entry point for the causative agent of fire blight. Furthermore, they are probably already part of the human diet, suggesting they might be safe for consumption, and thus are promising candidates for biocontrol applications.
One-Pot Synthesis of Pt High Index Facets Catalysts for Electrocatalytic Oxidation of Ethanol
Authors: Guo Ruihua , An Na , Huang Yarong , Guan Lili , Zhang Guofang , Zhu Guofu , Liu Zhaogang
Published: December 2022

Direct ethanol fuel cell (DEFC) has attracted wide attention due to its wide range of fuel sources, cleanliness, and high efficiency. However, the problems of low catalytic efficiency and poor catalyst stability still exist in DEFC catalysts, which restrict its rapid development. With chloroplatinic acid (H2PtCl6·6H2O) as the precursor, Polyvinylpyrrolidone (PVP) plays the role of surfactant, stabilizer, and reducing agent in the experiment. Glycine is the surface control agent and co-reducing agent. Pt high-index facets nanocatalyst was prepared with the one-pot hydrothermal method by adjusting the amount of PVP and glycine. X-Ray Diffraction (XRD), transmission electron microscope (TEM), and scanning electron microscope (SEM) were used to characterize the micro-structure of the nanocatalyst, and the influence of PVP and glycine on the synthesis of high-index facets catalyst was studied. The electrocatalytic performance of the catalyst was tested with an electrochemical workstation, and it was found that the performance of the prepared catalyst was better than that of the commercial catalyst. When the mass ratio of PVP and Pt was 50:1 and the molar ratio of glycine and Pt was 24:1, Pt nanocatalysts with {310}, {520} and {830} high exponential facets were prepared. The electrochemical test results showed that the peak current density of ethanol oxidation was 2.194 m2/g, and the steady-state current density was 0.241 mA/cm2, which was 5.7 times higher than that of commercial catalyst. The results of this paper show that due to the defects such as steps and kinks on the surface of the high-index facets, the active sites are increased, thus showing excellent electrocatalytic performance. This study provides a theoretical basis for the development and commercial application of high index facets nanocatalysts.