bluuebunny/crossref_metadata_2025 huggingface dataset:
An Investigation of the Thermal Properties of LM13- Quartz- Fly-Ash Hybrid Composites
Authors: Murthy B. R. N. , Ambekar Amar Murthy , Hiremath Anupama
Published: March 2024

In the present work, a metal–matrix composite was casted using the LM13 aluminum alloy, which is most widely used for casting automotive components. Such applications require materials to withstand high operating temperatures and perform reliably without compromising their properties. In this regard, particulate-reinforced composites have gained widespread adaptability. The particulate reinforcements used comprise of one of the widely available industrial by-products. which is fly ash, along with the abundantly available quartz. Hybrid composites are fabricated through the economical liquid route that is widely used in mass production. Though there are numerous published research articles investigating the mechanical properties of metal–matrix composites, very few investigated the thermal properties of the composites. In the present work, thermal properties such as thermal conductivity and thermal diffusivity of cast hybrid composites were evaluated. The particulate reinforcements were added in varied weight percentages to the molten LM13 alloy and were dispersed uniformly using a power-driven stirrer. The melt with the dispersed particulate reinforcements was then poured into a thoroughly dried sand mold, and the melt was allowed to solidify. The quality of the castings was ascertained through density evaluation followed by a microstructural examination. It was found that the composites with only the fly ash particles as a reinforcement were less dense in comparison to the composites cast with the quartz particulate reinforcement. However, the hybrid composite, with both particulate reinforcements were dense. The microstructure revealed a refined grain structure. The thermal diffusivity and thermal conductivity values were lower for the composites cast with only the fly ash reinforcement. On the other hand, the composites cast with only quartz as the particulate reinforcement exhibited higher thermal diffusivity and thermal conductivity. The specific heat capacity was found to be lower for the fly ash-reinforced composites and higher for the quartz-reinforced composites in comparison to the LM13 base matrix alloy. However, the highest value of thermal diffusivity and thermal conductivity were reported for the hybrid composites with a 10 wt.% inclusion of both fly ash and quartz particulate reinforcements.
Injectable Micro-Hydrogel for DNA Delivery: A Promising Therapeutic Platform
Authors: Moon Sunghyun , Lee Jong Bum
Published: March 2024

Utilizing the immune system as a strategy for disease prevention and treatment is promising, especially with dendritic cells (DCs) playing a central role in adaptive immune responses. The unique properties of DCs drive interest in developing materials for cell-based therapy and immune modulation. Injectable systems require syringe-compatible scaffolds, while hydrogels, like alginate, known for their programmability and biocompatibility, offer a versatile platform for immune medicine enhancement through easy preparation and room-temperature cross-linking. In this study, we synthesized alginate balls loaded with DCs or cytosine–phosphorothioate–guanine deoxyribonucleotide (CpG DNA) microparticles, aiming for long-term immune cell culture with potential immune stimulation effects. Encapsulated DCs exhibited proliferation within the alginate balls for up to 7 days, and CpG MPs were uniformly dispersed, which can facilitate uptake by DCs. This was supported by the result that DCs effectively phagocytosed CpG microparticles in a 2D environment. After the uptake of CpG MPs, the alginate balls with CpG-MP-uptaken DCs were synthesized successfully. The injectable properties of the alginate balls were easily modulated by adjusting the syringe needle gauges. This innovative strategy holds substantial promise for advancing medical treatments, offering effective and comfortable solutions for controlled immune modulation.
Three-Dimensional Printing Methods for Bioceramic-Based Scaffold Fabrication for Craniomaxillofacial Bone Tissue Engineering
Authors: Sheikh Zeeshan , Nayak Vasudev Vivekanand , Daood Umer , Kaur Anupreet , Moussa Hanan , Canteenwala Abbas , Michaud Pierre-Luc , de Fátima Balderrama Ísis , de Oliveira Sousa Edisa , Tovar Nick , Torroni Andrea , Glogauer Michael , Talib Huzefa , Coelho Paulo G. , Witek Lukasz
Published: March 2024

Three-dimensional printing (3DP) technology has revolutionized the field of the use of bioceramics for maxillofacial and periodontal applications, offering unprecedented control over the shape, size, and structure of bioceramic implants. In addition, bioceramics have become attractive materials for these applications due to their biocompatibility, biostability, and favorable mechanical properties. However, despite their advantages, bioceramic implants are still associated with inferior biological performance issues after implantation, such as slow osseointegration, inadequate tissue response, and an increased risk of implant failure. To address these challenges, researchers have been developing strategies to improve the biological performance of 3D-printed bioceramic implants. The purpose of this review is to provide an overview of 3DP techniques and strategies for bioceramic materials designed for bone regeneration. The review also addresses the use and incorporation of active biomolecules in 3D-printed bioceramic constructs to stimulate bone regeneration. By controlling the surface roughness and chemical composition of the implant, the construct can be tailored to promote osseointegration and reduce the risk of adverse tissue reactions. Additionally, growth factors, such as bone morphogenic proteins (rhBMP-2) and pharmacologic agent (dipyridamole), can be incorporated to promote the growth of new bone tissue. Incorporating porosity into bioceramic constructs can improve bone tissue formation and the overall biological response of the implant. As such, employing surface modification, combining with other materials, and incorporating the 3DP workflow can lead to better patient healing outcomes.
A Comparison of the Structure and Selected Mechanical Properties of Cr/Co Alloys Obtained by Casting and Selective Laser Melting
Authors: Klimek Leszek , Bułhak Barbara , Śmielak Beata
Published: March 2024

Selective laser melting (SLM) technologies are becoming increasingly popular. The aim of the work is to compare the metallographic structure, hardness, and selected strength properties of alloys obtained by casting and by SLM, with a particular emphasis on fatigue strength. Twenty Cr/Co alloy bars were made by casting or SLM, and samples of appropriate dimensions were prepared for individual tests. The microstructures of the samples were tested by metallography, and then tested for hardness, impact strength, tensile strength, bending strength, and fatigue strength; they were also subjected to fracture after bending, tensile, fatigue, and impact tests, with the resulting fractures examined by scanning electron microscopy (SEM). Primary dendrites and small amounts of gas bubbles were present in the cast samples ground lengthwise. The SEM samples were more finer grained and uniform. Compared to the casting samples, the SLM samples demonstrated higher hardness, lower mean impact strength and higher tensile strength. The casting samples also displayed lower mean elongation values. The casting samples demonstrated slightly higher fatigue strength. The fractures of the casting samples showed an interdendritic character with clearly visible dendrites at the fracture, while those of the SLM samples were also intergranular, but finer grained. SLM generally results in better strength properties, while casting obtains slightly greater fatigue strength.
Point-to-Point-Based Optimization Method of Ballast Water Allocation for Revolving Floating Cranes with Experimental Verification
Authors: Wang Xiaobang , Yu Yang , Li Siyu , Zhang Jie , Liu Zhijie
Published: March 2024

The Revolving Floating Crane (RFC) is a specialized engineering vessel crucial for offshore lifting operations, such as offshore platform construction and deep-water salvaging. It boasts impressive lifting capacity, good adaptability to various environmental conditions, and high operational efficiency. Conventionally, the safety and stability of RFC operations heavily depend on manual ballast water allocation, which is directly influenced by factors such as personnel status and sea conditions. These manual operations often result in reduced lifting efficiency, higher energy consumption, and compromised operational safety. In response, this paper introduces a ballast water-allocation approach based on the Point-to-Point (PTP) theory for the intelligent operation process of the RFC. The fundamental principles of the PTP theory are analyzed, and a method tailored to optimize ballast water allocation for RFC is proposed. Considering the unique characteristics of the ballast system and the specific requirements of lifting operations, an optimization model for PTP-based ballast water allocation is established. Numerical experiments are conducted to verify the efficacy and reliability of the proposed method. Comparing it to the conventional approaches, the results demonstrate a notable 17.75% reduction in energy consumption and an impressive 73.49% decrease in decision-making time, showcasing the superiority of the proposed approach. Finally, the engineering feasibility of the PTP-based optimization method for ballast water allocation is validated through actual lifting experiments, underscoring its potential to enhance RFC operations.
Editorial of the Special Issue “Novel Oil–Water Separation Technologies Applied in Marine Environmental Science”
Authors: Yang Qiang
Published: March 2024

The marine environment, a vital component of the Earth’s ecosystem, is increasingly threatened by pollution, and notably by oil spills [...]
Numerical Study on Wave Dissipation and Mooring Force of a Horizontal Multi-Cylinder Floating Breakwater
Authors: Zang Zhipeng , Fang Zhuo , Qiao Kuan , Zhao Limeng , Zhou Tongming
Published: March 2024

A three-dimensional numerical model was established based on ANSYS-AQWA (R19.0) software for the purpose of analyzing the hydrodynamic characteristics of a floating breakwater. This study examines three distinct floating breakwaters with different cross-sectional designs in order to evaluate their respective wave dissipation capabilities. It is suggested that the horizontal multi-cylinder floating breakwater exhibits a superior ability to dissipate waves when compared to both the single-cylinder and square pontoon configurations and can be deemed the most advantageous shielding strategy for potential engineering applications. Subsequently, this study examines the effects of influential parameters, including a large cylinder diameter, a small cylinder diameter, the angular position of the small cylinder, and the height and period of the incident wave, on the wave transmission coefficient. An empirical formula for the wave transmission coefficient was derived based on the numerical results. Additionally, the effects of influential parameters, including wind speed, current velocity, incident wave height and period, and water depth, on the maximum total mooring force were investigated. Furthermore, an empirical formula for the maximum total mooring force is proposed for practical implementation in engineering.
A Phase I/IIa Prospective, Randomized, Open-Label Study on the Safety and Efficacy of Nebulized Liposomal Amphotericin for Invasive Pulmonary Aspergillosis
Authors: Fortún Jesús , Gómez-García de la Pedrosa Elia , Martínez-Lorca Alberto , Paredes Patricia , Martín-Dávila Pilar , Gómez-López Alicia , Buitrago María José , López-Jiménez Javier , Gioia Francesca , Escudero Rosa , Alvarez-Alvarez Maria Elena , Soriano Cruz , Moreno-García Javier , San Miguel Diana , Vicente Noelia , Moreno Santiago
Published: March 2024

Although nebulized liposomal amphotericin B (NLAB) is being used in invasive pulmonary aspergillosis (IPA) prophylaxis, no clinical trial has shown its efficacy as a therapeutic strategy. NAIFI is the inaugural randomized, controlled clinical trial designed to examine the safety and effectiveness of NLAB (dosage: 25 mg in 6 mL, three times per week for 6 weeks) against a placebo, in the auxiliary treatment of IPA. Throughout the three-year clinical trial, thirteen patients (six NLAB, seven placebo) were included, with 61% being onco-hematological with less than 100 neutrophils/μL. There were no significant differences noted in their pre- and post-nebulization results of forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and oxygen saturation between the groups. Neither bronchospasm nor serum amphotericin B levels were reported in any patients given NLAB. 18F-Fluorodeoxyglucose positron emission tomography (FDG-PET-TC) was carried out at the baseline and after 6 weeks. A notable decrease in median SUV (standardized uptake value) was observed in NLAB patients after 6 weeks (−3.6 vs. −0.95, p: 0.039, one tail). Furthermore, a reduction in serum substance galactomannan and beta-D-Glucan was identified within NLAB recipients. NLAB is well tolerated and safe for patients with IPA. Encouraging indirect efficacy data have been derived from image monitoring or biomarkers. However, further studies involving more patients are necessary.
Remimazolam for Procedural Sedation in Older Patients: A Systematic Review and Meta-Analysis with Trial Sequential Analysis
Authors: Lee Myeongjong , Lee Cheol , Choi Guen Joo , Kang Hyun
Published: March 2024

This systematic review and meta-analysis with trial sequential analysis (TSA) aimed to evaluate the efficacy and safety of remimazolam compared to other sedatives for procedural sedation in older patients. We registered the protocol of this systematic review and meta-analysis with TSA in the PROSPERO network (CRD42023441209). Two investigators performed a systematic, comprehensive, and independent search of the PubMed, EMBASE, and Cochrane Central Register of Controlled Trials databases to identify randomized controlled trials (RCTs) comparing remimazolam with other sedatives in older patients undergoing procedural sedation. Conventional meta-analysis and TSA were also performed. Seven RCTs (1502 patients) were included. Pooled results demonstrated that remimazolam was associated with a low incidence of hypoxemia, hypotension, bradycardia, respiratory depression, and injection pain. Remimazolam also required a long time to cause loss of consciousness. There were no differences in rates of sedation success, dizziness/headache, postoperative nausea and vomiting, or recovery time. Older patients receiving procedural sedation with remimazolam had a lower risk of hypoxemia, hypotension, bradycardia, respiratory depression, and injection pain than those receiving other sedatives, suggesting that remimazolam may be more suitable for procedural sedation in older patients.
The Promise of Explainable AI in Digital Health for Precision Medicine: A Systematic Review
Authors: Allen Ben
Published: March 2024

This review synthesizes the literature on explaining machine-learning models for digital health data in precision medicine. As healthcare increasingly tailors treatments to individual characteristics, the integration of artificial intelligence with digital health data becomes crucial. Leveraging a topic-modeling approach, this paper distills the key themes of 27 journal articles. We included peer-reviewed journal articles written in English, with no time constraints on the search. A Google Scholar search, conducted up to 19 September 2023, yielded 27 journal articles. Through a topic-modeling approach, the identified topics encompassed optimizing patient healthcare through data-driven medicine, predictive modeling with data and algorithms, predicting diseases with deep learning of biomedical data, and machine learning in medicine. This review delves into specific applications of explainable artificial intelligence, emphasizing its role in fostering transparency, accountability, and trust within the healthcare domain. Our review highlights the necessity for further development and validation of explanation methods to advance precision healthcare delivery.
Long-Term Orientation and Tax Avoidance Regulations
Authors: Bilicka Katarzyna , Clancey-Shang Danjue , Qi Yaxuan
Published: March 2024

In this paper, we explore the relationship between the culture of the country where a multinational corporation (MNC) is headquartered and the MNC’s stock market reaction to tax avoidance regulations. Specifically, we examine the different responses of MNCs following the implementation of the 2010 UK reform that restricted profit shifting for a specific group of firms. We find that, in countries with short-term-oriented cultures, MNCs affected by this reform experienced positive stock market responses relative to their unaffected counterparts. This is not found in long-term-oriented cultures. This difference in response can partly be explained by the differing perceptions of the role tax havens play in tax minimization practices between more long-term-oriented cultures and those oriented towards the short term. We provide evidence that investors from more future-oriented cultures may recognize the short-lived effectiveness of a regulation ex ante, and thus price the quasi-exogenous market shock differently than their more short-term-oriented counterparts.
Emerging Trends in Play-to-Earn (P2E) Games
Authors: Duguleană Andreea Raluca , Tănăsescu Cristina Roxana , Duguleană Mihai
Published: March 2024

This research aims to establish the primary drivers influencing the development and consumers’ decision-making process in web3 games—decentralized games that function according to the play-to-earn paradigm. We observe several types of micro-economies developed within five play-to-earn games and highlight four roles consumers play at any given time. Our study offers a different perspective on rational consumer behaviour in cryptocurrency-based games and paves the way to better understanding their dynamics and evolution. Results shed light on the construction of in-game economies and how individuals of a given type engage in different playing activities. Furthermore, we compare the key features of web3 games with those similar to classic online games and assess if the play-and-earn implementations represent an evolution from previous revenue models. Using our proposed methodology, researchers can compare and classify any P2E games. We conclude by establishing a set of actions that enable consumers to benefit from this new phenomenon.
Public Perception of Online P2P Lending Applications
Authors: Khan Sahiba , Singh Ranjit , Baker H. Kent , Jain Gomtesh
Published: March 2024

This study examines significant topics and customer sentiments conveyed in reviews of P2P lending applications (apps) in India by employing topic modeling and sentiment analysis. The apps considered are LenDenClub, Faircent, i2ifunding, India Money Mart, and Lendbox. Using Latent Dirichlet Allocation, we identified and labeled 11 topics: application, document, default, login, reject, service, CIBIL, OTP, returns, interface, and withdrawal. The sentiment analysis tool VADER revealed that most users have positive attitudes toward these apps. We also compared the five apps overall and on specific topics. Overall, LenDenClub had the highest proportion of positive reviews. We also compared the prediction abilities of six machine-learning models. Logistic Regression demonstrates high accuracy with all three feature extraction techniques: bag of words, term frequency-inverse document frequency, and hashing. The study assists borrowers and lenders in choosing the most appropriate application and supports P2P lending platforms in recognizing their strengths and weaknesses.
Correction: Wang et al. Microarray Profile of Long Noncoding RNA and Messenger RNA Expression in a Model of Alzheimer’s Disease. Life 2020, 10, 64
Authors: Wang Linlin , Zeng Li , Jiang Hailun , Li Zhuorong , Liu Rui
Published: March 2024

We have updated the email addresses of Li Zeng and Hailun Jiang as the two authors’ previous email addresses are no longer in use [...]
Time to Recovery from Systolic Dysfunction Correlates with Left Ventricular Fibrosis in Arrhythmia-Induced Cardiomyopathy
Authors: Schach Christian , Lavall Daniel , Voßhage Nicola , Körtl Thomas , Meindl Christine , Ücer Ekrem , Hamer Okka , Maier Lars S. , Wachter Rolf , Sossalla Samuel
Published: March 2024

Background: Arrhythmia-induced cardiomyopathy (AIC) is characterized by the reversibility of left ventricular (LV) systolic dysfunction (LVSD) after rhythm restoration. This study is a cardiac magnetic resonance tomography substudy of our AIC trial with the purpose to investigate whether left ventricular fibrosis affects the time to recovery (TTR) in patients with AIC. Method: Patients with newly diagnosed and otherwise unexplainable LVSD and tachyarrhythmia were prospectively recruited. LV ejection fraction (LVEF) was measured by echocardiography at baseline and 2, 4, and 6 months after rhythm control, and stress markers were assessed. After initial rhythm control, LV fibrosis was assessed through late gadolinium enhancement (LGE). Patients were diagnosed with AIC if their LVEF improved by ≥15% (or ≥10% when LVEF reached ≥50%). Non-responders served as controls (non-AIC). Results: The LGE analysis included 39 patients, 31 of whom recovered (AIC). LV end-systolic diameters decreased and LVEF increased during follow-up. LV LGE content correlated positively with TTR (r = 0.63, p = 0.003), with less LGE favoring faster recovery, and negatively with ΔLVEF (i.e., LVEF at month 2 compared to baseline) as a marker of fast recovery (r = −0.55, p = 0.012), suggesting that LV fibrosis affects the speed of recovery. Conclusion: LV fibrosis correlated positively with the time to recovery in patients with AIC. This correlation may help in the estimation of the recovery period and in the optimization of diagnostic and therapeutic strategies for patients with AIC.
An Exercise Prescription for Patients with Stroke and Sarcopenia Based on the Modified Delphi Study
Authors: Yoo Jae Wan , Park Geun-Young , Park Hae-Yeon , Yoo Yeun Jie , Yoon Mi-Jeong , Song SeungYup , Park Kyung Hyun , Lee Hooman , Choi Sangui , Im Sun , Lim Seong Hoon
Published: March 2024

Background: We aimed to develop a consensus on the need for and priorities of exercise to treat preexisting sarcopenia with hemiplegic stroke. Methods: A modified three-round Delphi study was conducted. The panelists responded to the questionnaire on a 7-point Likert scale. Responses were returned with descriptive statistics in the next round. Consensus was defined as >75% agreement (score of 5–7) with a median > 5. The percentage of strong agreement (score of 6–7) and Kendall’s coefficient of concordance were calculated to demonstrate a more refined interpretation of the consensus. Results: Fifteen panelists contributed to all rounds. The need for exercise was demonstrated. The consensus was reached on 53 of 58 items in the first round and all items in the second and final rounds. The percentage of strong agreement was high for all but eight items. Conclusions: This study is the first Delphi study to investigate the need for and priorities of exercise for treating preexisting sarcopenia in stroke hemiplegia. We present a standard recommendation including 57 priorities and a strong recommendation including 49 priorities. The eight items that were excluded reflected factors that are less important to hemiplegic patients with poor balance, cognitive decline, or mental vulnerability.
Synthesis of (Z)-3-Allyl-5-(4-nitrobenzylidene)-2-sulfanylidene-1,3-thiazolidin-4-one and Determination of Its Crystal Structure
Authors: Moreno Bastien , Jourdain Isabelle , Knorr Michael , Boudriga Sarra , Strohmann Carsten , Schrimpf Tobias
Published: March 2024

To extend the existing library of arylidenerhodanines which display a potential biological activity, 3-N-allylrhodanine 1 was condensed under Knoevenagel conditions with p-nitrobenzaldehyde in acetic acid to afford the π-conjugated heterocyclic compound 3-allyl-5-(4-nitrobenzylidene)-2-sulfanylidene-1,3-thiazolidin-4-one 2. Compound 2 was characterized by IR and NMR spectroscopy, and its UV-vis spectrum was compared with that of compound 3-allyl-5-(4-methoxybenzylidene)-2-sulfanylidene-1,3-thiazolidin-4-one 3. The molecular structure is ascertained by a single-crystal X-ray diffraction study performed at 100 K.
Comparison of Linear and Nonlinear Twist Extrusion Processes with Crystal Plasticity Finite Element Analysis
Authors: Şimşek Ülke , Davut Kemal , Miyamoto Hiroyuki , Yalçinkaya Tuncay
Published: March 2024

The mechanical characteristics of polycrystalline metallic materials are influenced significantly by various microstructural parameters, one of which is the grain size. Specifically, the strength and the toughness of polycrystalline metals exhibit enhancement as the grain size is reduced. Applying severe plastic deformations (SPDs) has a noticeable result in obtaining metallic materials with ultrafine-grained (UFG) microstructure. SPD, executed through conventional shaping methods like extrusion, plays a pivotal role in the evolution of the texture, which is closely related to the plastic behavior and ductility. A number of SPD processes have been developed to generate ultrafine-grained materials, each having a different shear deformation mechanism. Among these methods, linear twist extrusion (LTE) presents a non-uniform and non-monotonic form of severe plastic deformation, leading to significant shifts in the microstructure. Prior research demonstrates the capability of the LTE process to yield consistent, weak textures in pre-textured copper. However, limitations in production efficiency and the uneven distribution of grain refinement have curbed the widespread use of LTE in industrial settings. This has facilitated the development of an improved novel method, that surpasses the traditional approach, known as the nonlinear twist extrusion procedure (NLTE). The NLTE method innovatively adjusts the channel design of the mold within the twist section to mitigate strain reversal and the rotational movement of the workpiece, both of which have been identified as shortcomings of twist extrusion. Accurate anticipation of texture changes in SPD processes is essential for mold design and process parameter optimization. The performance of the proposed extrusion technique should still be studied. In this context, here, a single crystal (SC) of copper in billet form, passing through both LTE and NLTE, is analyzed, employing a rate-dependent crystal plasticity finite element (CPFE) framework. CPFE simulations were performed for both LTE and NLTE of SC copper specimens having <100> or <111> directions parallel to the extrusion direction initially. The texture evolution as well as the cross-sectional distribution of the stress and strain is studied in detail, and the performance of both processes is compared.
A Study on the Nanostructural Evolution of Bi/C Anode Materials during Their First Charge/Discharge Processes
Authors: Zhao Mengyuan , Cheng Weidong , Wang Xin , Liu Huanyan , Chen Xiang , Wang Chaohui , You Yuan , Wu Zhaojun , Wang Bing , Wu Zhonghua , Xing Xueqing
Published: March 2024

As a candidate anode material for Li-ion batteries, Bi-based materials have attracted extensive attention from researchers due to their high specific capacity, environmental friendliness, and simple synthesis methods. However, Bi-based anode materials are prone to causing large volume changes during charging and discharging processes, and the effect of these changes on lithium storage performance is still unclear. This work introduces that Bi/C nanocomposites are prepared by the Bi-based MOF precursor calcination method, and that the Bi/C nanocomposite maintains a high specific capacity (931.6 mAh g−1) with good multiplicative performance after 100 cycles at a current density of 100 mA g−1. The structural evolution of Bi/C anode material during the first cycle of charging and discharging is investigated using in situ synchrotron radiation SAXS. The SAXS results indicate that the multistage scatterers of Bi/C composite, used as an anode material during the first lithiation, can be classified into mesopores, interspaces, and Bi nanoparticles. The different nanostructure evolutions of three types of Bi nanoparticles were observed. It is believed that this result will help to further understand the complex reaction mechanism of Bi-based anode materials in Li-ion batteries.
Data Augmentation of a Corrosion Dataset for Defect Growth Prediction of Pipelines Using Conditional Tabular Generative Adversarial Networks
Authors: Ma Haonan , Geng Mengying , Wang Fan , Zheng Wenyue , Ai Yibo , Zhang Weidong
Published: March 2024

Due to corrosion characteristics, there are data scarcity and uneven distribution in corrosion datasets, and collecting high-quality data is time-consuming and sometimes difficult. Therefore, this work introduces a novel data augmentation strategy using a conditional tabular generative adversarial network (CTGAN) for enhancing corrosion datasets of pipelines. Firstly, the corrosion dataset is subjected to data cleaning and variable correlation analysis. The CTGAN is then used to generate external environmental factors as input variables for corrosion growth prediction, and a hybrid model based on machine learning is employed to generate corrosion depth as an output variable. The fake data are merged with the original data to form the synthetic dataset. Finally, the proposed data augmentation strategy is verified by analyzing the synthetic dataset using different visualization methods and evaluation indicators. The results show that the synthetic and original datasets have similar distributions, and the data augmentation strategy can learn the distribution of real corrosion data and sample fake data that are highly similar to the real data. Predictive models trained on the synthetic dataset perform better than predictive models trained using only the original dataset. In comparative tests, the proposed strategy outperformed other data generation methods.
Corrosion of Stainless Steel in Simulated Nuclear Reactor Primary Coolant—Experiments and Modeling
Authors: Bojinov Martin , Betova Iva , Karastoyanov Vasil , Avdeev Georgi
Published: March 2024

In the present paper, the effect of the evolution of primary water chemistry during power operation on the corrosion rate and conduction mechanism of oxide films on stainless steel is studied by in situ impedance spectroscopy at 300 °C/9 MPa during 1-week exposure periods in an autoclave connected to a recirculation loop. At the end of the exposure period, the samples were anodically polarized in a wide range of potentials to evaluate the stability of the passive oxide. Separate samples of the same steel were simultaneously exposed to the coolant and subsequently analyzed by glow discharge optical emission spectroscopy (GDOES) in order to estimate the thickness and the in-depth composition of the formed oxides. Impedance data were quantitatively interpreted using the mixed-conduction model for oxide films (MCM) to estimate the rates of metal oxidation at the alloy/oxide interface, oxide dissolution and restructuring at the film/coolant interface, and ion transport in the protective corrosion layer.
Anisotropic Hardening and Plastic Evolution Characterization on the Pressure-Coupled Drucker Yield Function of ZK61M Magnesium Alloy
Authors: You Jianwei , Liu Jiangnan , Zhou Can , Gao Wei , Yao Yuhong
Published: March 2024

This paper studies the plastic behavior of the ZK61M magnesium alloy through a combination method of experiments and theoretical models. Based on a dog-bone specimen under different loading directions, mechanical tests under uniaxial tension were carried out, and the hardening behavior was characterized by the Swift–Voce hardening law. The von Mises yield function and the pressure-coupled Drucker yield function were used to predict the load–displacement curves of the ZK61M magnesium alloy under various conditions, respectively, where the material parameters were calibrated by using inverse engineering. The experimental results show that the hardening behavior of the ZK61M magnesium alloy has obvious anisotropy, but the effect of the stress state is more important on the strain hardening behavior of the alloy. Compared with the von Mises yield function, the pressure-coupled Drucker yield function is more accurate when characterizing the plastic behavior and strain hardening in different stress states of shear, uniaxial tension, and plane strain tension for the ZK61M alloy.
Effect of K+ Diffusion on Hydration of Magnesium Potassium Phosphate Cement with Different Mg/P Ratios: Experiments and Molecular Dynamics Simulation Calculations
Authors: Leng Difei , Fu Qiuyan , Ge Yunlu , He Chenhao , Lv Yang , Li Xiangguo
Published: March 2024

Magnesium potassium phosphate cement (MKPC) is formed on the basis of acid–base reaction between dead burnt MgO and KH2PO4 in aqueous solution with K-struvite as the main cementitious phase. Due to the unique characteristics of these cements, they are suitable for special applications, especially the immobilization of radioactive metal cations and road repair projects at low temperature. However, there are few articles about the hydration mechanism of MKPC. In this study, the types, proportions and formation mechanism of MKPC crystalline phases under different magnesium to phosphorus (Mg/P) ratios were studied by means of AAS, ICP-OES, SEM, EDS and XRD refinement methods. Corresponding MD simulation works were used to explain the hydration mechanism. This study highlights the fact that crystalline phases distribution of MKPC could be adjusted and controlled by different Mg/P ratios for the design of the MKPC, and the key factor is the kinetic of K+.
Investigation of Flexural Bearing Behavior of Corroded RC Strengthened with U-Type TRC
Authors: Xie Wei , Sheng Jie , Yu Zongjian , Zhu Jiong , Zhou Binbin , Chen Ke
Published: March 2024

In this study, the flexural bearing behavior of corroded reinforced concrete (RC) beams reinforced with U-type Textile Reinforced Concrete (TRC) was investigated using a four-point bending loading method. Nine test beams were produced: one original beam, three RC beams with corrosion alone, and five corroded beams strengthened with U-type TRC. The analysis focuses on assessing the impacts of the steel corrosion degree and the number of textile layers on various aspects of the bending behavior, such as failure modes, bearing capacity, and load displacement curves, in U-type TRC-strengthened corroded beams. The experimental results revealed three distinct failure modes in the U-type TRC-strengthened corroded beams. TRC effectively enhanced the bearing capacity. With sufficient textile layers, it can be restored to the level of the original RC beams. Moreover, in the cases of severe corrosion in RC beams, the bearing capacity increased more significantly. The TRC also enhanced the ductility. Finally, a calculation equation for the ultimate bearing capacity of U-type TRC-strengthened corroded beams was presented and validated, demonstrating consistent alignment with the experimental data.
Mechanical Properties of Fully Recycled Aggregate Concrete Reinforced with Steel Fiber and Polypropylene Fiber
Authors: Zhang Lijuan , Li Xiang , Li Changbin , Zhao Jun , Cheng Shengzhao
Published: March 2024

The study and utilization of fully recycled aggregate concrete (FRAC), in which coarse and fine aggregates are completely replaced by recycled aggregates, are of great significance in improving the recycling rate of construction waste, reducing the carbon emission of construction materials, and alleviating the ecological degradation problems currently faced. In this paper, investigations were carried out to study the effects of steel fiber (0.5%, 1.0%, and 1.5%) and polypropylene fiber (0.9 kg/m3, 1.2 kg/m3 and 1.5 kg/m3) on the properties of FRAC, including compressive strength, splitting tensile strength, the splitting tensile load–displacement curve, the tensile toughness index, flexural strength, the load–deflection curve, and the flexural toughness index. The results show that the compressive strength, splitting tensile strength, and flexural strength of fiber-reinforced FRAC were remarkably enhanced compared with those of ordinary FRAC, and the maximum increase was 56.9%, 113.3%, and 217.0%, respectively. Overall, the enhancement effect of hybrid steel–polypropylene fiber is more significant than single-mixed fiber. Moreover, the enhancement of the crack resistance, tensile toughness, and flexural toughness obtained by adding steel fiber to the FRAC is more significant than that obtained by adding polypropylene fiber. Furthermore, adding polypropylene fiber alone and mixing it with steel fiber showed different FRAC splitting tensile and flexural properties.
Crevice Corrosion Behavior of 201 Stainless Steel in NaCl Solutions with Different pH Values by In Situ Monitoring
Authors: Zhu Zejie , Zhang Hang , Bai Yihan , Liu Pan , Yuan Haoran , Wang Jiangying , Cao Fahe
Published: March 2024

Crevice corrosion (CC) behavior of 201 stainless steel (SS) in 1 M NaCl + x M HCl/y M NaOH solutions with various pH was investigated using SECM and optical microscopic observations. Results show that the CC was initiated by the decrease in pH value within the crevice. The pH value near the crevice mouth falls rapidly to 1.38 in the first 2 h in the strongly acidic solution, while the pH value was observed to rise firstly and then decrease in the neutral and alkaline solutions. It indicates there is no incubation phase in the CC evolution of 201-SS in a pH = 2.00 solution, while an incubation phase was observed in pH = 7.00 and 11.00 solutions. Additionally, there appeared to be a radial pH variation within the gap over time. The pH value is the lowest at the gap mouth, which is in line with the in situ optical observation result that the severely corroded region is at the mouth of the gap. The decrease in pH value inside results in the negative shift of open circuit potential (OCP) and the initiation of CC of 201-SS. The increased anodic dissolution rate in the acidic solution accelerates the breakdown of passive film inside, reducing the initiation time and stimulating the spread of CC.
Formation of Grown-In Nitrogen Vacancies and Interstitials in Highly Mg-Doped Ammonothermal GaN
Authors: Zajac Marcin , Kaminski Paweł , Kozlowski Roman , Litwin-Staszewska Elzbieta , Piotrzkowski Ryszard , Grabianska Karolina , Kucharski Robert , Jakiela Rafal
Published: March 2024

The formation of intrinsic point defects in the N-sublattice of semi-insulating Mg-doped GaN crystals grown by the ammonothermal method (SI AT GaN:Mg) was investigated for the first time. The grown-in defects produced by the displacement of nitrogen atoms were experimentally observed as deep traps revealed by the Laplace transform photoinduced transient spectroscopy in the compensated p-type crystals with the Mg concentrations of 6 × 1018 and 2 × 1019 cm−3 and resistivities of ~1011 Ωcm and ~106 Ωcm, respectively. In both kinds of materials, three closely located traps with activation energies of 430, 450, and 460 meV were revealed. The traps, whose concentrations in the stronger-doped material were found to be significantly higher, are assigned to the (3+/+) and (2+/+) transition levels of nitrogen vacancies as well as to the (2+/+) level of nitrogen split interstitials, respectively. In the material with the lower Mg concentration, a middle-gap trap with the activation energy of 1870 meV was found to be predominant. The results are confirmed and quantitatively described by temperature-dependent Hall effect measurements. The mechanism of nitrogen atom displacement due to the local strain field arising in SI AT GaN:Mg is proposed and the effect of the Mg concentration on the charge compensation is discussed.
The Fabrication of Ultrahigh-Strength Steel with a Nanolath Structure via Quenching–Partitioning–Tempering
Authors: Xu Wenting , Xie Li , Liu Xiaoying , Wang Jiangnan , Xu Yuxuan , He Mingtao , Hu Kejun , Liu Chang , Yu Wei
Published: March 2024

A novel low-alloy ultrahigh-strength steel featuring excellent mechanical properties and comprising a nanolath structure was fabricated in this work using a quenching–partitioning–tempering (Q-P-T) process. The Q-P-T process comprised direct quenching and an isothermal bainitic transformation for partitioning after thermo-mechanical control processing (online Q&P) and offline tempering (reheating and tempering). The ultrafine nanolath martensite/bainite mixed structure, combined with residual austenite in the form of a thin film between the nanolaths, was formed, thereby conferring excellent mechanical properties to the steel structures. After the Q-P-T process, the yield and tensile strengths of the steels reached 1450 MPa and 1726 MPa, respectively. Furthermore, the Brinell hardness and elongation rate were 543 HB and 11.5%, respectively, with an average impact energy of 20 J at room temperature.
Structural Parameters and Behavior in Simulated Body Fluid of High Entropy Alloy Thin Films
Authors: Craciun Doina , Laszlo Edwin A. , Mirza-Rosca Julia C. , Dorcioman Gabriela , Geanta Victor , Voiculescu Ionelia , Craciun Gabriel , Badea Liviu , Craciun Valentin
Published: March 2024

The structure, composition and corrosion properties of thin films synthesized using the Pulsed Laser Deposition (PLD) technique starting from a three high entropy alloy (HEA) AlCoCrFeNix produced by vacuum arc remelting (VAR) method were investigated. The depositions were performed at room temperature on Si and mirror-like polished Ti substrates either under residual vacuum (low 10−7 mbar, films denoted HEA2, HEA6, and HEA10, which were grown from targets with Ni concentration molar ratio, x, equal to 0.4, 1.2, and 2.0, respectively) or under N2 (10−4 mbar, films denoted HEN2, HEN6, and HEN10 for the same Ni concentration molar ratios). The deposited films’ structures, investigated using Grazing Incidence X-ray Diffraction, showed the presence of face-centered cubic and body-centered cubic phases, while their surface morphology, investigated using scanning electron microscopy, exhibited a smooth surface with micrometer size droplets. The mass density and thickness were obtained from simulations of acquired X-ray reflectivity curves. The films’ elemental composition, estimated using the energy dispersion X-ray spectroscopy, was quite close to that of the targets used. X-ray Photoelectron Spectroscopy investigation showed that films deposited under a N2 atmosphere contained several percentages of N atoms in metallic nitride compounds. The electrochemical behavior of films under simulated body fluid (SBF) conditions was investigated by Open Circuit Potential (OCP) and Electrochemical Impedance Spectroscopy measurements. The measured OCP values increased over time, implying that a passive layer was formed on the surface of the films. It was observed that all films started to passivate in SBF solution, with the HEN6 film exhibiting the highest increase. The highest repassivation potential was exhibited by the same film, implying that it had the highest stability range of all analyzed films. Impedance measurements indicated high corrosion resistance values for HEA2, HEA6, and HEN6 samples. Much lower resistances were found for HEN10 and HEN2. Overall, HEN6 films exhibited the best corrosion behavior among the investigated films. It was noticed that for 24 h of immersion in SBF solution, this film was also a physical barrier to the corrosion process, not only a chemical one.
Investigation and Validation of a Shape Memory Alloy Material Model Using Interactive Fibre Rubber Composites
Authors: Annadata Achyuth , Acevedo-Velazquez Aline , Woodworth Lucas , Gereke Thomas , Kaliske Michael , Röbenack Klaus , Cherif Chokri
Published: March 2024

The growing demand for intelligent systems with improved human-machine interactions has created an opportunity to develop adaptive bending structures. Interactive fibre rubber composites (IFRCs) are created using smart materials as actuators to obtain any desired application using fibre-reinforced elastomer. Shape memory alloys (SMAs) play a prominent role in the smart material family and are being used for various applications. Their diverse applications are intended for commercial and research purposes, and the need to model and analyse these application-based structures to achieve their maximum potential is of utmost importance. Many material models have been developed to characterise the behaviour of SMAs. However, there are very few commercially developed finite element models that can predict their behaviour. One such model is the Souza and Auricchio (SA) SMA material model incorporated in ANSYS, with the ability to solve for both shape memory effect (SME) and superelasticity (SE) but with a limitation of considering pre-stretch for irregularly shaped geometries. In order to address this gap, Woodworth and Kaliske (WK) developed a phenomenological constitutive SMA material model, offering the flexibility to apply pre-stretches for SMA wires with irregular profiles. This study investigates the WK SMA material model, utilizing deformations observed in IFRC structures as a reference and validating them against simulated models using the SA SMA material model. This validation process is crucial in ensuring the reliability and accuracy of the WK model, thus enhancing confidence in its application for predictive analysis in SMA-based systems.
Bending Behavior of Hybrid Timber–Steel Beams
Authors: Haase Peter , Aurand Simon , Boretzki Jakob , Albiez Matthias , Sandhaas Carmen , Ummenhofer Thomas , Dietsch Philipp
Published: March 2024

Driven by climate change and the need for a more sustainable construction sector, policy is increasingly demanding and promoting timber hybrid construction methods. In the German state of Baden-Württemberg, every new public building has to be of timber or timber hybrid construction (Holzbauoffensive BW). The objective of multi-story buildings with large floor spans can only be achieved in a resource-efficient way by hybrid constructions combining timber and steel components. A research project recently completed at the Karlsruhe Institute of Technology was aimed at the development and systematic investigation of hybrid bending beams in which an advantageous combination of the materials steel and timber is used. For this purpose, steel profiles are integrated into timber cross-sections in a shear-resistant manner by adhesive bonding. As part of the experimental, numerical and analytical investigations, different cross-sections of steel and timber, as well as different construction materials, were considered (GL24h, LVL48p, LVL80p, S355 and S420). The results of large-scale four-point bending tests illustrate the potential of this new hybrid construction method. Depending on the geometry and material combinations tested, the bending stiffness could be increased by up to 250%, and the load-carrying capacity by up to 120%, compared to a glulam beam with identical dimensions.