bluuebunny/crossref_metadata_2025 huggingface dataset:
Prognosis of Atrial Fibrillation with or without Comorbidities: Analysis of Younger Adults from a Nationwide Database
Authors: Mertz Valentin , Cottin Yves , Bentounes Sid Ahmed , Pastier-Debeaumarché Julie , Didier Romain , Herbert Julien , Zeller Marianne , Lip Gregory Y. H. , Fauchier Laurent
Published: April 2022

Objective: To assess the prognosis of AF patients with or without cardiac or extra-cardiac concomitant conditions. Participants and Methods: All consecutive patients diagnosed with AF admitted to French hospitals between 2011 and 2020 were identified. Patients were classified into four groups: (1) > 60 yo; (2) with known cardiac disease (KCD group); (3) with extra-cardiac comorbidities (ECC); and 4) AF without KCD or ECC (“Lone AF”). Results: Altogether 2,435,541 patients were identified, from which 2,203,702 patients aged >60 years and 231,839 patients aged <60 years (with KCD (55.2%), with ECC (14.7%) and with “Lone AF” (30.1%)). During follow-up, the incidences of all-cause and CV deaths were 13.7%, 5.7%, 6.2%, and 2.3%, and 4.2%, 1.7%, 0.8%, and 0.3% in the older than 60 yo group, KCD group, ECC group and “Lone AF” AF group, respectively. In the age and sex-adjusted analysis (patients < 60 yo), patients with AF and KCD had worse outcomes than patients with “Lone AF” for all major cardiac events. Conclusion: There are three distinct prognostic criteria based on the presence or lack of HD or extra-cardiac concomitant comorbidities. Patients in the so-called “Lone AF” group remain severe in terms of CV events but still with a lower incidence than the patients with associated KCD or ECC. The presence of KCD or ECC makes it possible to distinguish a profile in terms of events that are very different between the patients.
A Novel Inductorless Design Technique for Linear Equalization in Optical Receivers
Authors: Abdelrahman Diaaeldin , Williams Christopher , Liboiron-Ladouceur Odile , Cowan Glenn E. R.
Published: April 2022

To mitigate the trade-off between gain and bandwidth of CMOS multistage amplifiers, a receiver front-end (FE) that employs a high-gain narrowband transimpedance amplifier (TIA) followed by an equalizing main amplifier (EMA) is proposed. The EMA provides a high-frequency peaking to extend the FE’s bandwidth from 25% to 60% of the targeted data rate fbit. The peaking is realized by adding a pole in the feedback paths of an active feedback-based wideband amplifier. By embedding the peaking in the main amplifier (MA), the front-end meets the sensitivity and gain of conventional equalizer-based receivers with better energy efficiency by eliminating the equalizer stages. Simulated in TSMC 65 nm CMOS technology, the proposed front-end achieves 7.4 dB and 6 dB higher gain at 10 Gb/s and 20 Gb/s, respectively, compared to a conventional front-end that is designed for equal bandwidth and dissipates the same power. The higher gain demonstrates the capability of the proposed technique in breaking the gain-bandwidth trade-off. The higher gain also reduces the power penalty incurred by the decision circuit and improves the sensitivity by 1.5 dB and 2.24 dB at 10 Gb/s and 20 Gb/s, respectively. Simulations also confirm that the proposed FE exhibits a robust performance against process and temperature variations and can support large input currents.
Flexural Fatigue Test—A Proposed Method to Characterize the Lifetime of Conductor Tracks on Polymeric Substrates
Authors: Petillon Simon , Knöller Andrea , Bräuer Philipp , Helm David , Grözinger Tobias , Weser Sascha , Eberhardt Wolfgang , Franke Jörg , Zimmermann André
Published: April 2022

High quality and long product life are two fundamental requirements for all circuit carriers, including molded interconnect devices (MID), to find application in various fields, such as automotive, sensor technology, medical technology, and communication technology. When developing a MID for a certain application, not only the design, but also the choice of material as well as the process parameters need to be carefully considered. A well-established method to evaluate the lifetime of such MID, respective of their conductor tracks, is the thermal shock test, which induces thermomechanical stresses upon cycling. Even though this method has numerous advantages, one major disadvantage is its long testing time, which impedes rapid developments. Addressing this disadvantage, this study focuses on the laser direct structuring of thermoplastic LCP Vectra E840i LDS substrates and the subsequent electroless metallization of the commonly used layer system Cu/Ni/Au to force differences in the conductor tracks’ structure and composition. Performing standardized thermal shock tests alongside with flexural fatigue tests, using a customized setup, allows comparison of both methods. Moreover, corresponding thermomechanical simulations provide a direct correlation. The flexural fatigue tests induce equivalent or even higher mechanical stresses at a much higher cycling rate, thus drastically shorten the testing time.
Underwater Absorber for a Remotely Operated Vehicle
Authors: Xu Pengfei , Han Chenbo , Lv Tao , Cheng Hongxia
Published: April 2022

Fixed-point underwater hovering is a key technology for the reliable operation of a remotely operated vehicle in the ocean to inspect the surfaces of a variety of underwater structures, such as ports and offshore wind power facilities. This study proposes an underwater wall absorber that can be used in remotely operated vehicles. First, we explain the working principle of the underwater absorber. Second, we analyze the main factors affecting its adsorption performance by using numerical simulations. Finally, we show the results of a tested prototype of the proposed absorber, whose performance was consistent with the results of numerical calculations. The proposed absorber may have important technical prospects for use in remotely operated underwater vehicles.
Digitalization in Maritime Transport and Seaports: Bibliometric, Content and Thematic Analysis
Authors: Jović Marija , Tijan Edvard , Brčić David , Pucihar Andreja
Published: April 2022

In this paper, a bibliometric, content and thematic analysis of digitalization in maritime transport and seaports was performed. The research was primarily motivated by the scarcity of similar works offering a comprehensive and recent literature analysis, the advancements of the maritime digitalization itself, and its influence on all related processes. The initial investigation phase considered 8178 publications, leading through the research steps to the final inclusion of 280 papers, the thematic and content analysis of which were performed using various bibliometric tools. The research encompassed various criteria, ranging through databases, keywords, topics, research areas and others. The resulting concept map emphasized the main concepts that digitalization in maritime transport relies on, or strives towards. The aim of the study was to address the fundamental research questions, with the tendency to define the main key points in the current maritime transport and seaport digitalization process. It can be concluded that an increasing number of authors recognize the importance of new digital technologies in maritime transport and seaports. However, with new digital technologies come specific risks such as spoofing or data manipulation that need to be further analyzed.
Do Rock Design Formulas Based on Wave Flume Experiments Reliably Model Their Performance at Sea?
Authors: Losada Miguel A. , Díaz-Carrasco Pilar , Clavero María
Published: April 2022

The mean sea level rising predicted for this century and the following centuries will make necessary to protect most of the human properties located on the coast. One of the alternatives is the construction of slope breakwaters along hundreds of kilometers of coastline. For coastal engineering this task is a social/environmental and economic/financial challenge, in particular the optimization of the total costs of the structure during its useful life. It is common to design these structures with the Van der Meer stability formula, assuming that the uncertainty of the project is due to maritime agents. Today, this approach is no longer valid and must be reconsidered to adapt to the social and environmental demands. The main source of uncertainty of the Van der Meer formula is epistemic, associated with its ability to predict the progression of failure modes of the structure. This study analyses the actual formula of design coastal structures and discusses the limitations for predicting damage progression, which directly affects designing strategies and total lifetime conservation and repair costs of the structure. It is shown that these limitations derive from: (1) design and experimental technique of the wave flume to propose the formula; (2) non-dimensional variables and parameters included in the formula; and (3) the method of application. It seems desirable and urgent to review and update the state of knowledge and tools for slope breakwater design to meet the demand for protection of human properties on the coast.
EE-UWSNs: A Joint Energy-Efficient MAC and Routing Protocol for Underwater Sensor Networks
Authors: Alablani Ibtihal Ahmed , Arafah Mohammed Amer
Published: April 2022

In Underwater Sensor Networks (UWSNs), the energy sources of sensor nodes are limited and difficult to recharge and solar energy cannot be used in that environment. The power issue is one of the most significant constraints in underwater sensor networks and energy balancing is essential to prolong the network lifetime. The MAC/routing protocols that are used in other types of networks may not be suitable for UWSNs due to their unique characteristics. This paper aims to overcome the energy problem by developing a new MAC/routing protocol for UWSNs called the Energy-Efficient protocol for UWSNs (EE-UWSNs). It is based on five principles to save sensor energy and to prolong the lifetime of UWSNs. These principles are using finite levels of power, applying the multi-hops transmission, narrowing the scope of transmission, applying inactivation mode, and balancing energy consumption. Using the AUVNetSim simulator, which is a Python project developed by the Massachusetts Institute of Technology (MIT), the proposed EE-UWSNs protocol was compared with well-known protocols. Simulation results proved that the proposed protocol reduces the average energy consumption of sensors by up to 68.49% compared with the other protocols. Furthermore, the average number of collisions and the end-to-end delay are enhanced.
Deep versus Moderate Neuromuscular Blockade in Gynecologic Laparoscopic Operations: Randomized Controlled Trial
Authors: Kathopoulis Nikolaos , Protopapas Athanasios , Stamatakis Emmanouil , Chatzipapas Ioannis , Zacharakis Dimitrios , Grigoriadis Themos , Athanasiou Stavros , Valsmidis Dimitrios
Published: April 2022

Background: To investigate whether deep neuromuscular blockade (NMB) improves surgical conditions and postoperative pain compared to moderate block, in patients undergoing gynecologic laparoscopic surgery. Methods: A single blind, randomized, controlled trial was undertaken with laparoscopic gynecologic surgical patients, who were randomly assigned to one of the following two groups: patients in the first group received deep NMB (PTC 0-1) and in the other, moderate NMB (TOF 0-1). Primary outcomes included assessing the surgical conditions using a four-grade scale, ranging from 0 (extremely poor) to 3 (optimal), and patients’ postoperative pain was evaluated with a five-grade Likert scale and the analgesic consumption. Results: 144 patients were analyzed as follows: 73 patients received deep NMB and 71 moderate NMB. Mean surgical field scores were comparable between the two groups (2.44 for moderate vs. 2.68 for deep NMB). Regarding postoperative pain scores, the patients in the deep NMB experienced significantly less pain than in the group of moderate NMB (0.79 vs. 1.58, p < 0.001). Moreover, when the consumption of analgesic drugs was compared, the moderate NMB group needed more extra opioid analgesia than the deep NMB group (18.3% vs. 4.1%, p = 0.007). From the secondary endpoints, an interesting finding of the study was that patients on deep NMB had significantly fewer incidents of subcutaneous emphysema. Conclusions: Our data show that, during the performance of gynecologic laparoscopic surgery, deep NMB offers no advantage of operating filed conditions compared with moderate NMB. Patients may benefit from the deep block as it may reduce postoperative pain.
Family Risk Factors That Jeopardize Child Development: Scoping Review
Authors: Simões Aida , Lopes Saudade , dos Anjos Dixe Maria , Fernandes Júlio Belo
Published: April 2022

The obligation to protect children is defined by law. However, there is fragility in identifying actual or potential situations that jeopardize their development. This review aims to identify the family risk factors that jeopardize child development. A scoping review was conducted following the Joanna Briggs Institute for Evidence-Based Practice framework and the 2020 Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. The research was carried out on the electronic databases PubMed, CINAHL, Nursing & Allied Health Collection: Comprehensive, MEDLINE Complete, and MedicLatina, with a time limit of 2010 to 2021. The search was restricted to documents written in Portuguese, English, and French. A total of 3998 articles were initially identified. After selecting and analysing, 28 risk factors were extracted from 29 articles. Four categories of risk factors were identified—namely, patterns of social and economic interaction, family characteristics, caregiver’s characteristics, and parenting. The results of this review allow the identification of family risk factors that jeopardize child development. This is significant for Child Protective Services workers as they carry out their risk assessments. This assessment is the first step in avoiding an accumulation of harm to at-risk children and allowing the development of interventions for minimising harm’s impact on children’s development.
Mean Reversions in Major Developed Stock Markets: Recent Evidence from Unit Root, Spectral and Abnormal Return Studies
Authors: Nguyen James , Li Wei-Xuan , Chen Clara Chia-Sheng
Published: April 2022

We revisited the issue of return predictability in three major developed markets (USA, UK and Japan) using a unique dataset from the Wharton Research Data Services database and a comprehensive set of traditional and recent statistical methods. We specifically employed a variety of traditional linear and nonlinear tests, latest multiple-break unit root tests and spectral analysis to test the efficient market hypothesis. Our results show that these stock markets generally are inefficient. We further explored whether the departure from market efficiency can be used to generate profitable trades and found that abnormal returns exist in all three markets. We found evidence of abnormal returns associated with the break dates identified in the models which are correlated with major historical events around the world. Our findings have important implications for investors and policymakers.
Ideal Sodium Dialysate Concentration: A Brazilian Perspective
Authors: Pecoits-Filho Roberto
Published: April 2022

The current interpretation of the controversial and dynamic nature of the literature reports in this area leads me to lean towards the preference of a standard DNa+ in the upper range (138 mEq/L) of the current international utilization and preference of clinical directors in Brazil. My opinion to individualize (plus and minus 2 mmol/L of DNa+ prescription) would be based on clinically relevant signals of excessive interdialytic weight gain and uncontrolled hypertension (to decrease DNa+ concentration), or intradialytic hypotension episodes (to increase DNa+ concentration). In my experience, the individualization, based on this approach, would be applicable to a minority (less than 15%) of patients. As new data from randomized clinical trials emerge (particularly the robust RESOLVE trial), I would certainly need (and would be happy) to revise my point of view on this issue.
Landscape Conservation Assessment in the Latin American Tropics: Application and Insights from Costa Rica
Authors: Vlami Vassiliki , Morera Beita Carlos , Zogaris Stamatis
Published: April 2022

Landscape quality is an important aspect of conservation and sustainable development, yet holistic assessments of landscapes in the Latin American tropics are scarce. Here we employ an onsite survey across Costa Rica using the Landscape Assessment Protocol (LAP), a rapid assessment method, to assess the conservation condition of landscape views. In a survey of 50 landscape view sites in different parts of the country, LAP’s 15 metrics (evaluation criteria) were effective in providing an index for landscape quality showing a gradient of degradation in response to various modern anthropogenic pressures. The response of the index over a variety of landscape types correlates well with the Human Footprint anthropogenic pressure assessment, an independent land degradation index. Urban and peri-urban landscape types showed the most degraded conditions relative to flatland, coastal, and upland types on all metrics. Despite certain subjective attributes, the assessment method seems effective in providing a quality condition index that may assist in quality characterization and in promoting participation in landscape interpretation, landscape literacy, and landscape-scale conservation initiatives, especially in a region where landscape views (scenic resources) are threatened by widespread land-use changes. Finally, recommendations are made for the further application and testing of LAP, specifically for use in the neotropics.
Analyzing the Interrelationships among Various Ecosystem Services from the Perspective of Ecosystem Service Bundles in Shenyang, China
Authors: Gan Shuang , Xiao Yu , Qin Keyu , Liu Jingya , Xu Jie , Wang Yangyang , Niu Yingnan , Huang Mengdong , Xie Gaodi
Published: April 2022

An understanding of the relationships among multiple ecosystem services (ES) facilitates ecosystem management and decision-making. The study of ES bundles can well explain the complex interactions between different ES in a region. Shenyang is a significant economic development and food production area in Northeast China, with a diverse range of ES types. In this study, we quantified eleven ES from Shenyang, China (two provisioning services, eight regulating services, and one cultural service). The trade-offs and synergies among ES were analyzed by Spearman’s correlation analysis. The ES bundles were identified using principal component analysis and k-means cluster analysis. Finally, the random forest method was employed to identify the driving factors affecting the ES bundles. The results showed: (1) all ES in Shenyang improved between 2000 and 2019; (2) the most obvious trade-off was found between sand fixation and water conservation; (3) the ES in the study region could be clustered into five different ES bundles which were primarily affected by land-use type; and (4) social-ecological factors largely explained and predicted the formation and distribution of ES bundles. The study provides reference information for the management and optimization of Shenyang’s ecosystems and land use regulation.
Moving from Industry 4.0 to Industry 5.0: What Are the Implications for Smart Logistics?
Authors: Jefroy Niloofar , Azarian Mathew , Yu Hao
Published: April 2022

Background: Given the importance of human centricity, resilience, and sustainability, the emerging concept of Industry 5.0 has pushed forward the research frontier of the technology-focused Industry 4.0 to a smart and harmonious socio-economic transition driven by both humans and technologies, where the role of the human in the technological transformation is predominantly focused on. Several studies discuss the impacts of disruptive technologies on smart logistics operations in Industry 4.0. However, since Industry 5.0 is a new concept and still in its infancy, its implications for smart logistics have not been discussed. Methods: To fill this gap, this paper presents a comparative bibliometric analysis to show the connection and differences between Industry 4.0 and Industry 5.0 and their implications for smart logistics. A thorough content analysis is then given to illustrate the features of smart logistics in Industry 5.0 concerning four areas, namely intelligent automation, intelligent devices, intelligent systems, and intelligent materials. Results: The results show that, compared with Industry 4.0, the research of smart logistics in Industry 5.0 puts more focus on the interaction between humans and technology in the digital transition, with the increasing adoption of collaborative technologies, e.g., human-machine systems, collaborative robots, and human-robot collaboration. Conclusions: Finally, a research agenda is proposed for identifying future research directions of smart logistics in Industry 5.0.
Rheological and Frictional Properties of Lithium Complex Grease with Graphene Additives
Authors: Wang Yanshuang , Gao Xudong , Lin Jianghai , Zhang Pu
Published: April 2022

Few-layer graphene (FLG) was added as a nano-additive to lithium complex grease (LCG) to explore the influence of FLG on the microstructure, viscoelasticity, friction and wear properties of LCG. Studies have found that the addition of FLG makes the microstructure of the thickener more compact, which in turn leads to an increase in the viscoelasticity of LCG. FLG additives can improve the viscosity-temperature properties of the grease and change the elastic deformation response to temperature changes. Among the temperatures selected in this article, the effect of graphene is more obvious at 70 °C. During the friction process, a proper amount of FLG can quickly form a boundary film and is not easily damaged, thereby optimizing the friction and wear performance of LCG.
Effect of Tempering Temperature on Microstructure and Sulfide Stress Cracking of 125 Ksi Grade Casing Steel
Authors: Luo Ming , Zhou Gao-Yang , Shen Han , Wang Xin-Tian , Li Mou-Cheng , Zhang Zhong-Hua , Cao Guang-Hui
Published: April 2022

The influence of tempering temperature on the microstructure of 0.5Cr0.4W steels was investigated by scanning electron microscope, and the roles of grain boundary character, dislocation, and Taylor factor in sulfide stress cracking (SSC) resistance were interpreted using the election backscattered diffraction technique. The 0.5Cr0.4W steels tempered at 690 °C, 700 °C, and 715 °C all showed tempered martensites. The specimen tempered at 715 °C exhibited a higher critical stress intensity factor (KISSC) of 34.58 MPa·m0.5, but the yield strength of 800 MPa did not meet the criterion of 125 ksi (862 MPa) grade. When the specimen was tempered at 690 °C, the yield strength reached 960 MPa and the KISSC was only 21.36 MPa·m0.5, displaying poorer SSC resistance. The 0.5Cr0.4W steel tempered at 700 °C showed a good combination of yield strength (887 MPa) and SSC resistance (KISSC: 31.16 MPa·m0.5). When increasing the tempering temperature, the local average misorientation and Taylor factor of the 0.5Cr0.4W steels were decreased. The reduced dislocation density, and greater number of grains amenable to slippage, produced less hydrogen transport and a lower crack sensitivity. The SSC resistance was, thus, increased, owing to the minor damage to hydrogen aggregation. Therefore, 700 °C is a suitable tempering temperature for 0.5Cr0.4W casing steel.
Application of Graphite Electrode Plasma Heating Technology in Continuous Casting
Authors: Wang Yong , Song Jingxin , Cheng Nailiang , Guo Zhenhe , Li Jingshe , Yang Shufeng , Zhao Mengjing , Wang Cun
Published: April 2022

In this study, the industrial, experimental effect of a plasma heating system in the form of graphite electrode in the tundish of double-strand slab caster was evaluated for the first time. The system uses three graphite electrodes, two of which are cathodes and one of which is an anode, to form a conductive loop through molten steel in the tundish. The system is built on an old two-strand slab caster and is installed on the premise that the original ladle tundish equipment remains unchanged. The normal working power of the system is up to 1500 kW, and the heating rate of molten steel in the tundish can reach 1.0 °C/min under conditions of 5 t/min total steel throughput and a tundish capacity of 50 t. After the system was put into operation, the purity of molten steel undergoing heating was investigated. The sample analysis of low carbon steel and ultra-low carbon steel before and after heating showed that the contents of N and O in the steel did not increase, while the size of the oxide inclusions near the heating point increased but showed little change in terms of the overall quantity. This process benefited from the addition of inert gas during the heating process to control the atmosphere in the heating area, which prevents reoxidation. The sample analysis also showed that there is no obvious carbon absorption phenomenon after heating, and the fluctuation in C content is within 0.0001%, which is consistent with the general production results. By using this system, the temperature of molten steel in the steelmaking process can be reduced by 10~15 °C, allowing continuous low superheat casting to be supported, which is helpful for reducing production costs and improving the solidified structure inside the slab. The results of the study show that the plasma heating technology can be applied to the continuous casting of low carbon–nitrogen steel slabs, which shows the benefits of reducing emissions and improving production efficiency.
Nanoengineering of N-doped Mesoporous Carbon Nanoparticles with Adjustable Internal Cavities via Emulsion-Induced Assembly
Authors: Wang Cong , Zhao Xiaoxi , Wang Xiufang , Tian Yong
Published: April 2022

The preparation of mesoporous carbonaceous materials with particularly adjustable morphology is currently a hot area of research in mesoporous materials. Herein, a novel approach is reported for the construction of N-doped multicavity mesoporous carbon nanoparticles (NMMCNs) based on the “emulsion swelling–acid curing mechanism” using a nanoemulsion assembly method under a high-speed shearing force. Intriguingly, this approach adopted a novel acid (HCl) curing procedure. Impressively, the morphology evolution from an internal multicavity to a single cavity and then to a non-cavity interior structure could be accomplished by simply varying the synthesis parameters. Additionally, this synthesis approach ingeniously overcame the following problems: (i) technically, the employment of high temperatures and high pressures in traditional hydrothermal reaction curing environments is avoided; (ii) this approach removes the requirement for silicon coating, which provides a limited pyrolysis condition, to obtain a multi-chamber structure. Resveratrol (Res) is an insoluble natural medicine and was successfully loaded into NMMCNs, thereby the Res–NMMCNs delivery system was constructed. Importantly, the Res–NMMCNs delivery system could still retain the antitumor and antioxidant activity of Res in vitro.
Modification of Hydrogenation and Corrosion Properties of Hydrogen Storage Material by Amorphous TiCrFeCoNi HEA Layer
Authors: Giemza Agnieszka , Sozańska Maria , Bala Henryk
Published: April 2022

The effect of encapsulation of LaNi4.5Co0.5 powdered hydrogen storage material with ≈0.5 µm thick, magnetron-sputtered amorphous film of TiCrFeCoNi high-entropy alloy (HEA) on functional hydrogenation parameters of the hydride electrode is discussed. The multicycle galvanostatic charge/discharge tests carried out in deaerated, 6 M KOH solution allow for determining specific capacity decrease, exchange current density of the H2O/H2 system, and high rate discharge ability (HRD) of the hydride electrodes. Concentrations of individual constituents of the HEA in the particle coating determined by EDS analysis were practically the same (≈20 at.%) as in the applied TiCrFeCoNi target material. The XRD phase analysis pointed out the amorphous structure of the HEA coating. The presence of HEA coating decreases capacity by 10–15 per cent, but increases exchange current density for H2O/H2 system. The effect of HEA on capacity fade is ambiguous: low for 10–25 cycles (most probably due to effective corrosion inhibition) and distinct at long-term cycling (most probably due to galvanic effects resulting from mechanical degradation of particle surface). The presence of HEA coating considerably improves the HRD of the electrode material: for a discharge rate of 5C, the HRD coefficient becomes 4.6 times greater for HEA modified storage material.
Research on the Mechanism and Prevention Methods of the Drying Shrinkage Effect of Earthen Sites
Authors: Zhang Zehuan , Yang Jianzhong , Yue Jianwei , Li Wenhao , Gao Huijie
Published: April 2022

In view of the fact that it is easy for the ancient city soil site of Cai Kingdom to expand and crack when encountering water, this paper explores the methods to improve the expansion and shrinkage deformation, dry shrinkage cracks and easy water absorption characteristics of the expanded site soil based on a lime and silicone hydrophobic agent. In this paper, the expansive clay in the old city site of Cai Kingdom in Zhumadian was taken as the research object, and the dry-shrinkage fissure test of saturated expansive soil was carried out, to study the influencing factors of the dry-shrinkage cracking of expansive soil in this area. The site soil was modified with lime and glue powder, and the fissure image was quantitatively analyzed by MATLAB. The test shows that the smaller the particle size, the faster the evaporation of water and the smaller the surface fissure rate; the thicker the thickness of the soil sample, the greater the surface fissure rate and the greater the crack width; and with the increase in the number of drying and wetting cycles, the surface fissure rate of the soil sample increases. In this paper, lime and waterproof materials are used to improve the expansive soil. This not only reduces the dry shrinkage crack rate, but also improves the waterproof performance and durability of expansive soil.
Enhancing the Impact Strength of Prepacked Aggregate Fibrous Concrete Using Asphalt-Coated Aggregates
Authors: Vatin Nikolai Ivanovich , Murali Gunasekaran , Abid Sallal R. , de Azevedo Afonso Rangel Garcez , Tayeh Bassam A. , Dixit Saurav
Published: April 2022

The brittleness of plain concrete represents a significant issue to the integrity of concrete structures when subjected to impact loading. Recent rapid industrialization has attracted researchers to find a solution for concrete brittleness and enhance its ductility. In light of this, the prepacked aggregate fibrous concrete (PAFC) with single and double precoated coarse aggregates using asphalt is proposed and examined. Nine different mixtures were designed using polypropylene and steel fibre of 3% dosage with single and double asphalt-coated aggregates. Specimens were prepared with natural aggregate and 100% C-graded asphalt-coated aggregate to evaluate their impact strength. The ACI Committee 544 drop-weight impact standard was followed in the testing of all specimens. Results indicated that using asphalt-coated aggregate can improve the impact energies of concrete. The impact energy at cracking and failure of the single asphalt-coated aggregate specimen was 1.55 and 2.11 times higher, while the double-coated aggregate specimens exhibited 1.73 and 2.56 times greater than the natural aggregate specimen, respectively. The contribution of fibres in enhancing the impact resistance is remarkable compared to the single- and double-coated aggregates used in PAFC.
Mechanical Characteristics of the Flebogrif System—The New System of Mechano-Chemical Endovenous Ablation
Authors: Terlecki Piotr , Boryga Marek , Kołodziej Paweł , Gołacki Krzysztof , Stropek Zbigniew , Janczak Dariusz , Antkiewicz Maciej , Zubilewicz Tomasz
Published: April 2022

Non-thermal endovenous ablations, due to the lowest probability of complications, are the new method of treating chronic venous insufficiency—one of the most common diseases globally. The Flebogrif system (Balton Sp. z o.o., Warsaw, Poland) is a new mechano-chemical ablation system causing the mechanical damage of endothelium that allows for better sclerosant penetration into its wall. The purpose of the article is to provide mechanical characteristics in the form of force–displacement dependence for a single cutting element, and a bundle of cutting elements of Flebogrif as a whole for different levels of protrusion of the bundle of cutting elements. A TA.HD plus (Stable Micro Systems, Godalming, UK) analyzer equipped with special handles, was used for characteristics testing. The head movement speed used was 5 mm·s−1. The Flebogrif system was tested for three cutting element protrusion levels: L = Lmax, L = 0.9·Lmax, and L = 0.8·Lmax. Before testing, geometric measurement of the spacing of the cutting elements for three proposed protrusions was performed. It was established that decreasing the working length of the cutting elements will increase their rigidity, and, as a result, increase the force exerted on the internal surface of the vein wall. The obtained characteristics will allow for specifying contact force variability ranges and the corresponding diameter ranges of operated veins.
Study on the Tribological Behaviour of Nanolubricants during Micro Rolling of Copper Foils
Authors: Ma Linan , Zhao Jingwei , Zhang Mingya , Jiang Zhengyi , Zhou Cunlong , Ma Xiaoguang
Published: April 2022

Water-based lubricants with different fractions of TiO2 nanoparticles ranging from 1.0 to 9.0 wt.% were utilized to study the lubrication mechanisms during micro rolling tests and the tribological behaviour of nanolubricants during the micro rolling of copper foils. The results indicate that the application of TiO2 nanolubricants remarkably improves the surface quality of rolled copper foils during rolling processes. For lubricants with inadequate TiO2 nanoparticles, it is found that few TiO2 nanoparticles enter the contact regions between the rolls and foils, causing insufficient lubrication during rolling processes. Instead, for lubricants with excessive TiO2 nanoparticles, obvious agglomeration occurs at the contact regions and promotes the generation of voids on the surface of the rolled foils, thereby deteriorating the surface quality of the rolled copper foils. In addition, it is found that the surface quality of rolled foils is improved by utilizing a large reduction ratio. Overall, the fraction of 3.0 wt.% TiO2 nanolubricants is optimal to improve the lubrication conditions at the contact regions, thereby improving the surface quality of the rolled copper foils.
Magnetite Nanoparticles: Synthesis and Applications in Optics and Nanophotonics
Authors: Dudchenko Nataliia , Pawar Shweta , Perelshtein Ilana , Fixler Dror
Published: April 2022

Magnetite nanoparticles with different surface coverages are of great interest for many applications due to their intrinsic magnetic properties, nanometer size, and definite surface morphology. Magnetite nanoparticles are widely used for different medical-biological applications while their usage in optics is not as widespread. In recent years, nanomagnetite suspensions, so-called magnetic ferrofluids, are applied in optics due to their magneto-optical properties. This review gives an overview of nanomagnetite synthesis and its properties. In addition, the preparation and application of magnetic nanofluids in optics, nanophotonics, and magnetic imaging are described.
Low-Pressure Plasma-Processed Ruthenium/Nickel Foam Electrocatalysts for Hydrogen Evolution Reaction
Authors: Liu Chen , Tseng Chia-Yun , Wang Ying-Chyi , Cheng I-Chun , Chen Jian-Zhang
Published: April 2022

In this paper, low-pressure 95%Ar–5%H2, pure Ar, and 95%Ar–5%O2 plasmas were used for post-treatment of ruthenium (Ru) deposited on nickel foam (NF) (Ru/NF). Ru/NF was then tested as a catalyst for a hydrogen evolution reaction. Significant improvement in electrocatalytic activity with the lowest overpotential and Tafel slope was observed in an alkaline electrolyte (1 M KOH) with 95%Ar–5%O2 plasma processing on Ru/NF. Linear scanning electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) also indicate the lowest interfacial impedance and largest electrical double layer capacitance. Experimental results with 0.1 M phosphate buffered saline (PBS) and 0.5 M H2SO4 electrolytes were also demonstrated and compared.
Experimental Study of Flexural Performance of UHPC–NC Laminated Beams Exposed to Fire
Authors: Zhou Tieming , Sheng Xingwang
Published: April 2022

In recent decades, reinforced-concrete bridges have experienced premature deterioration and other problems during service due to severe environmental effects such as fire and corrosion. Previous studies have shown that the use of ultra-high-performance concrete (UHPC) can improve the durability of bridge structures. In this study, four-point bending tests were conducted on twelve UHPC–NC laminated beams with different UHPC-layer heights and at different temperatures in order to evaluate their flexural performance under fire conditions. The test variables were the UHPC heights (20 mm, 50 mm, 80 mm) and temperatures (20 °C, 200 °C, 400 °C, 600 °C), and the effects on the flexural load capacity of UHPC–NC laminated beams under the influence of these factors were investigated. The test results show that the increase in temperature causes the concrete color to change from grayish blue to white and leads to a significant decrease in the flexural load capacity of the stacked beams. The height of the UHPC layer has an important effect on the stiffness of the stacked beams and delays the formation of local cracks, thus improving the durability of the stacked beams.
Effect of Graphene Addition on the Thermal and Persistent Luminescence Properties of Gd2.994Ce0.006Ga3Al2O12 and Gd2.964Ce0.006Dy0.03Ga3Al2O12 Ceramics
Authors: Kujawa Daniela , Szewczyk Daria , Boiko Vitalii , Bęben Damian , Głuchowski Paweł
Published: April 2022

The gadolinium, gallium, aluminum garnet doped with cerium and co-doped with dysprosium ions were prepared using sol gel method. The SEM images show that after synthesis, the grains are below 100 nm. The powders were ultrasonically mixed with graphene nanoflakes and ceramics were prepared using the high pressure low temperature sintering technique. A series of the ceramics was prepared using different graphene content. The structure of the samples was examined using X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman techniques. The spectroscopic properties were checked using conventional and persistent luminescence spectra measurements. The thermoluminescence glow curves and fading time of persistent luminescence measurements were performed to check how the graphene presence affects the electron traps number and depth. It was found that the addition of graphene improved the thermal conductivity of co-doped samples. This resulted in faster release of deeper traps and an increase in fading of persistent luminescence. The possibility of releasing energy from deep traps without additional stimulation may allow the use in different applications, the matrices and luminescent ions, which so far did not show persistent luminescence at room temperature.
Explosion Test and Numerical Simulation of Coated Reinforced Concrete Slab Based on BLAST Mitigation Polyurea Coating Performance
Authors: Lyu Ping , Fang Zhiqiang , Wang Xu , Huang Weibo , Zhang Rui , Sang Yingjie , Sun Pengfei
Published: April 2022

The mechanical strength, thermal stability, thermal performance, and microstructure of Qtech T26 blast mitigation polyurea (T26 polyurea) were studied using quasi-static and dynamic mechanical experiments, thermogravimetric experiments, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) experiments, and contact explosion and non-contact explosion experiments with polyurea-coated reinforced concrete slabs. Additionally, the energy dissipation mechanism of the coating was analyzed. The blast mitigation ability and blast mitigation mechanism of T26 polyurea-coated reinforced concrete slabs were investigated by analyzing the macroscopic morphology of reinforced concrete slabs with or without coatings and the contact explosion simulation of polyurea-coated reinforced concrete slabs. The results showed that T26 polyurea exhibited a certain strain rate effect. Its initial thermal decomposition temperature reached 286 °C, and its thermal stability was good. After carbonization, carbon slag can form and adhere to the structural surface. The glass transition temperature Tgs of the soft segment was −44.9 °C, and the glass transition temperature Tgh of the hard segment was 36.5 °C, showing a certain amount of microphase separation morphology. After the explosion test, there was a small pit on the front surface of the coated reinforced concrete plate, and there was no damage on the back surface. The integrity of the plate was good. The uncoated reinforced concrete slab had a large crater on the front of the explosion surface, and the back of the explosion surface experienced explosion collapse, concrete crushing, and an overall loss of stability. The numerical simulation results showed that the failure mode of the coated plate was consistent with the test. The kinetic energy conversion rate of the uncoated reinforced concrete plate was 87.27%, and the kinetic energy conversion rate of the coated reinforced concrete plate was 95.36%. The T26 coating improved the kinetic energy conversion rate of the structure and improved the blast mitigation ability of the reinforced concrete plate structure.
Spring Back Behavior of Large Multi-Feature Thin-Walled Part in Rigid-Flexible Sequential Loading Forming Process
Authors: Zhang Yanfeng , Lang Lihui , Wang Yao , Chen Haizhou , Du Jianning , Jiao Zhihui , Wang Lin
Published: April 2022

The spring back behavior of large complex multi-feature parts in the rigid-flexible sequential forming process has certain special characteristics. The hydraulic pressure loading locus has a significant influence on the spring back of small features of the part, and the applicability of the spring back prediction model to the process needs further research. Therefore, this paper takes the large aluminum alloy inner panel of an automobile as the research object, and the spring back model and the influence laws of the hydraulic pressure loading locus are revealed by combining the theoretical analysis and numerical simulation with the process tests. Meanwhile, based on the theoretical prediction and experimental results, the spring back compensation of the complex inner panel is carried out. Results show that the hardening model has a greater impact on the accuracy of spring back prediction than the yield criterion does, and the prediction accuracy of Barlat’89 + Yoshida–Uemori mixed hardening model is the highest. Finally, the optimized loading locus of hydraulic pressure is obtained, and the accuracy results of the compensated parts verify the accuracy of the analysis model.
Bending and Straightening of a Medium Carbon Steel Continuous Casting Slab with Low Temperature End Plastic Groove
Authors: Yang Jingbo , Zhang Fujun , Li Jingshe , Liu Wei , Wang Tiantian , Yuan Hang , Cang Daqiang
Published: April 2022

The high temperature brittleness range of medium carbon microalloyed steel under an actual continuous casting process was determined by the high temperature tensile test. The test results revealed that only a third of the brittle temperature range from 650–825 °C was due to intergranular ferrite in the experimental steel. In addition, it was found that the plastic recovery was fast and stable when the temperature was lower than 725 °C (the lowest plastic temperature). Bending/straightening operation in this temperature range was conducive to controlling the generation of corner cracks. In order to keep the corner temperature at the low temperature end of the plastic curve when the slab was bent/straightened, the cooling water scheme of the secondary cooling zone of the continuous caster was formulated by numerical calculation. By appropriately increasing the cooling water flow in the foot roll and the secondary cooling zones 1–5, the corner temperature of slab during bending operation was 600–700 °C, avoiding the brittle temperature range. The industrial test was then carried out. The results showed that after using the optimized water volume, the corner grains of the slab were uniform and the microstructure was mainly pearlite + ferrite. In addition, the abnormally large grain size was reduced, and a large amount of ferrite was generated inside the grain, which avoided stress concentration at the corner of the slab during bending/straightening operation, and basically eliminated the corner crack of the slab.
New Composite Hydrogel Based on Whey and Gelatin Crosslinked with Copper Sulphate
Authors: Purcea Lopes Pompilia Mioara , Moldovan Dumitriţa , Moldovan Marioara , Carpa Rahela , Saroşi Codruţa , Păşcuţă Petru , Mazilu Moldovan Amalia , Fechete Radu , Popescu Violeta
Published: April 2022

By-products from the meat and dairy industries are important sources of high biological value proteins. This paper explores possibilities for improving the swelling and integrity of a cross-linked whey and gelatin hydrogel with different amounts of CuSO4 × 5H2O. Overall, swelling tests demonstrate that cross-linked samples show a better hydration capacity and stability in the hydration medium, but different copper concentrations lead to different swelling behavior. At concentrations smaller than 0.39%, the sample lasts for 75 h in a water environment before beginning to disintegrate. At a concentration of copper sulphate higher than 0.55%, the stability of the sample increased substantially. The swelling kinetics has been investigated. The diffusion constant values increased with the increase in copper concentration, but, at the highest concentration of copper (0.86%), its value has decreased. Spectroscopy analyses such as Fourier transform infrared (FT-IR), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-VIS), and nuclear magnetic resonance (NMR) relaxometry analyses revealed changes in the secondary and tertiary structure of proteins as a result of the interaction of Cu2+ ions with functional groups of protein chains. In addition to its cross-linking ability, CuSO4 × 5H2O has also shown excellent antibacterial properties over common bacterial strains responsible for food spoilage. The result of this research demonstrates the potential of this hydrogel system as a unique material for food packaging.
Broadband Perfect Absorber in the Visible Range Based on Metasurface Composite Structures
Authors: Wang Ran , Yue Song , Zhang Zhe , Hou Yu , Zhao Hongda , Qu Shitian , Li Man , Zhang Zichen
Published: April 2022

The broadband perfect absorption of visible light is of great significance for solar cells and photodetectors. The realization of a two-dimensional broadband perfect absorber in the visible range poses a formidable challenge with regard to improving the integration of optical systems. In this paper, we numerically demonstrate a broadband perfect absorber in the visible range from 400 nm to 700 nm based on metasurface composite structures. Simulation results show that the average absorptance is ~95.7% due to the combination of the intrinsic absorption of the lossy metallic material (Au) and the coupling resonances of the multi-sized resonators. The proposed perfect absorber may find potential applications in photovoltaics and photodetection.