bluuebunny/crossref_metadata_2025 huggingface dataset:
The Photoperiod Significantly Influences the Growth Rate, Digestive Efficiency, Immune Response, and Antioxidant Activities in the Juvenile Scalloped Spiny Lobster (Panulirus homarus)
Authors: Wang Yinggang , Yang Rui , Fu Zhengyi , Ma Zhenhua , Bai Zemin
Published: February 2024

This study aimed to elucidate the effects of different photoperiods (0 L:24 D, 6 L:18 D, 12 L:12 D, 18 L:6 D, 24 L:0 D, “Light (L) and Dark (D)”) on the growth performance and physiological responses of the juvenile scalloped spiny lobster (Panulirus homarus). Over a period of 56 days, parameters such as growth rate, digestive enzyme, immune enzyme, and antioxidant enzyme were meticulously evaluated in 90 lobsters subjected to these varying light conditions. The present study found no significant differences in survival rate (SR), molting frequency (MF), and meat yield production (MYP) among the various photoperiod treatments (p > 0.05). Notably, the highest weight gain rate (WGR) and specific growth rate (SGR) were observed under a 12 L:12 D photoperiod. In the continuous dark phase (0 L:24 D), pepsin (PEP) activity remained high in gastric tissues, while trypsin (TRYP) and chymotrypsin (CHT) activities reached the highest in hepatopancreas tissues. The α-amylase (AMS) activity in the hepatopancreas was most elevated under 18 L:6 D, and the optimal lipase (LPS) activity was recorded under 12 L:12 D. The activity of acid phosphatase (ACP) in the hepatopancreas was highest in the absence of light (0 L:24 D), whereas the activities of alkaline phosphatase (AKP) and lysozyme (LZM) were most effective under the 12 L:12 D photoperiod. The total antioxidant capacity (T-AOC), along with catalase (CAT) and superoxide dismutase (SOD) activities of the hepatopancreas reached the highest at 12 L:12 D. The highest activity of glutathione peroxidase (GSH-Px) was seen under 18 L:6 D. The concentration of malondialdehyde (MDA), a marker of oxidative stress, was found to be highest under 12 L:12 D. Consequently, this specific photoperiod is essential for achieving optimal growth and maintaining appropriate physiological balance in the scalloped spiny lobster during aquaculture. These findings provide a foundational guideline for establishing the lighting environment in the farming of the juvenile scalloped spiny lobster.
A Review of Numerical and Physical Methods for Analyzing the Coupled Hydro–Aero–Structural Dynamics of Floating Wind Turbine Systems
Authors: Maali Amiri Mojtaba , Shadman Milad , Estefen Segen F.
Published: February 2024

Recently, more wind turbine systems have been installed in deep waters far from the coast. Several concepts of floating wind turbine systems (FWTS) have been developed, among which, the semi-submersible platform—due to its applicability in different water depths, good hydrodynamic performance, and facility in the installation process—constitutes the most explored technology compared to the others. However, a significant obstacle to the industrialization of this technology is the design of a cost-effective FWTS, which can be achieved by optimizing the geometry, size, and weight of the floating platform, together with the mooring system. This is only possible by selecting a method capable of accurately analyzing the FWTS-coupled hydro–aero–structural dynamics at each design stage. Accordingly, this paper provides a detailed overview of the most commonly coupled numerical and physical methods—including their basic assumptions, formulations, limitations, and costs used for analyzing the dynamics of FWTS, mainly those supported by a semi-submersible—to assist in the choice of the most suitable method at each design phase of the FWTS. Finally, this article discusses possible future research directions to address the challenges in modeling FWTS dynamics that persist to date.
Multi-Parameter Fuzzy-Based Neural Network Sensorless PMSM Iterative Learning Control Algorithm for Vibration Suppression of Ship Rim-Driven Thruster
Authors: Yang Zhi , Yan Xinping , Ouyang Wu , Bai Hongfen , Xiao Jinhua
Published: February 2024

Aiming to reduce motor speed estimation and torque vibration present in the permanent magnet synchronous motors (PMSMs) of rim-driven thrusters (RDTs), a position-sensorless control algorithm using an adaptive second-order sliding mode observer (SMO) based on the super-twisting algorithm (STA) is proposed. In which the sliding mode coefficients can be adaptively tuned. Similarly, an iterative learning control (ILC) algorithm is presented to enhance the robustness of the velocity adjustment loop. By continuously learning and adjusting the difference between the actual speed and given speed of RDT motor through ILC algorithm, online compensation for the q-axis given current of RDT motor is achieved, thereby suppressing periodic speed fluctuations during motor running. Fuzzy neural network (FNN) training can be used to optimize the STA-SMO and ILC parameters of RDT control system, while improving speed tracking accuracy. Finally, simulation and experimental verifications have been conducted on the vector control system based on the conventional PI-STA and modified ILC-STA. The results show that the modified algorithm can effectively suppress the estimated speed and torque ripple of RDT motor, which greatly improves the speed tracking accuracy.
Expendable Conductivity–Temperature–Depth-Assisted Fast Underwater Sound Speed Estimation by Convolutional Neural Network with Reduced Fully Connected Layers
Authors: Li Sijia , Zhang Hao , Lu Jiajun , Wu Pengfei , Huang Wei
Published: February 2024

Obtaining accurate sound speed profiles (SSPs) in near-real-time is of great significance for ocean exploration, underwater communication and improving the performance of sonar systems. In response to the problem that traditional sound speed estimation methods cannot obtain real-time sound speed distribution or rely too much on sonar observation data, we propose an SSP estimation method based on a convolutional neural network with reduced fully connected layers (RFC-CNN) in this paper. This method utilizes neural networks to extract the complex nonlinear features of various types of data. With the help of the historical SSPs and shallow seawater sound speed and temperature data obtained by expendable conductivity–temperature–depth probes (XCTDs), a more accurate estimation of the regional sound speed distribution can be realized quickly. This approach can save the observation cost and significantly improve the real-time performance of SSP estimation.
Review of Asymmetric Seafloor Spreading and Oceanic Ridge Jumps in the South China Sea
Authors: Wei Jiangong , Dai Shuangling , Cheng Huai , Wang Houjin , Wang Pengcheng , Li Fuyuan , Xie Zhiyuan , Zhu Rongwei
Published: February 2024

Seafloor spreading is an important cornerstone of the theory of plate tectonics. Asymmetric seafloor spreading and oceanic ridge jumps are common phenomena in this process and play important roles in controlling oceanic crust accretion, regional tectonics and geological geometric boundaries. As the largest marginal sea in the western Pacific, the South China Sea is an ideal laboratory for dissecting the Wilson cycle of small marginal sea-type ocean basins restricted by surrounding blocks and exploring the deep dynamic processes of confined small ocean basins. In recent years, a lot of research has been conducted on the spreading history of the South China Sea and has achieved fruitful results. However, the detailed dynamic mechanisms of asymmetric seafloor spreading and ridge jumps are still unclear. Therefore, this paper summarizes the basic understanding about the dynamic mechanisms of global asymmetric seafloor spreading and ridge jumps and reviews the related research results of asymmetric seafloor spreading and ridge jumps in the South China Sea. Previous studies have basically confirmed that seafloor spreading in the South China Sea started between ~32 and 34 Ma in the east sub-basin and ended at ~15 Ma in the northwest sub-basin, with at least once oceanic ridge jump in the east sub-basin. The current research mainly focuses on the age of the seafloor spreading in the South China Sea and the location, time and stage of the ridge jumps, but there are relatively few studies on high-resolution lithospheric structure across these ridges and the dynamic mechanism of oceanic ridge jumps. Based on the current research progress, we propose that further studies should focus on the lithosphere–asthenosphere scale in the future, suggesting that marine magnetotelluric and Ocean Bottom Seismometer (OBS) surveys should be conducted across the residual oceanic ridges to perform a detailed analysis of the tectonics magmatism in the east sub-basin to gain insights into the dynamic mechanisms of oceanic ridge jumps and asymmetric seafloor spreading, which can promote understanding of the tectonic evolution of the South China Sea and improve the classical plate tectonics theory that was constructed based on the open ocean basins.
In-Line Inspection (ILI) Techniques for Subsea Pipelines: State-of-the-Art
Authors: Zhu Hai , Chen Jiawang , Lin Yuan , Guo Jin , Gao Xu , Chen Yuanjie , Ge Yongqiang , Wang Wei
Published: February 2024

Offshore oil and gas resources play a crucial role in supplementing the energy needs of human society. The crisscrossing subsea pipeline network, which serves as vital infrastructure for the storage and transportation of offshore oil and gas, requires regular inspection and maintenance to ensure safe operation and prevent ecological pollution. In-line inspection (ILI) techniques have been widely used in the detection and inspection of potential hazards within the pipeline network. This paper offers an overview of ILI techniques used in subsea pipelines, examining their advantages, limitations, applicable scenarios, and performance. It aims to provide valuable insights for the selection of ILI technologies in engineering and may be beneficial for those involved in pipeline integrity management and planning.
Quantitative and Qualitative Radiological Assessment of Sarcopenia and Cachexia in Cancer Patients: A Systematic Review
Authors: Mortellaro Sveva , Triggiani Sonia , Mascaretti Federica , Galloni Micol , Garrone Ornella , Carrafiello Gianpaolo , Ghidini Michele
Published: February 2024

Sarcopenia, an extremely common condition in cancer patients, is described as a progressive and generalized musculoskeletal disorder that is associated with an increased likelihood of adverse outcomes, including falls, fractures, physical disability, and mortality. By contrast, cachexia is defined as a syndrome characterized by weight loss with the concomitant loss of muscle and/or fat mass. Cancer cachexia leads to functional impairment, reduced physical performance, and decreased survival, and is often accompanied by cancer progression and reduced response to therapy. The literature states that cancer patients with cachexia or sarcopenia have many more complications than patients without these conditions. The interplay between physiologic sarcopenia and cancer cachexia is, in part, responsible for the complexity of studying wasting disorders in the cancer population, particularly in the geriatric population. For these reasons, a comprehensive assessment of the body composition and physical function of these patients is necessary. There are several modalities adapted to measure skeletal muscle mass, such as dual-energy X-ray absorptiometry (DEXA), bioelectrical impedance analysis (BIA), computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US). The gold standard for the measurement of quantitative and qualitative changes in body composition in patients with cancer is the analysis of tissue density using a CT scan. However, this technique remains poorly implemented in clinical practice because of the use of ionizing radiation. Similarly, DEXA, MRI, and US have been proposed, but their use is limited. In this review, we present and compare the imaging techniques that have been developed so far for the nutritional assessment of cancer patients.
Efficacity and Safety of the Fluocinolone Acetonide Implant in Uveitic Macular Edema: A Real-Life Study from the French Uveitis Network
Authors: Jabbour Matthieu , Kodjikian Laurent , Bourdin Alexandre , Rougier Marie-Bénédicte , Serrar Yasmine , Weber Michel , Massé Hélène , Mazhar Driss , Perez-Roustit Sara , Chiquet Christophe , Delyfer Marie Nöelle , Bodaghi Bahram , Touhami Sara
Published: February 2024

Purpose: To evaluate the safety and efficacy of the fluocinolone acetonide implant (FAi, Iluvien® Horus pharma, Nice, France) in non-infectious uveitic macular edema (UME) and to approach the predictive factors of treatment response. Methods: This retrospective, multicenter real-life study included patients with chronic non-infectious UME who received intravitreal FAi after at least two dexamethasone implants (DEXi). Results: Twenty-six eyes from 22 patients (73.1% of females) were included. The mean age was 60.4 ± 16 years. The mean follow-up was 11.4 ± 2 months. The mean baseline best-corrected visual acuity (BCVA) was 0.43 ± 0.36 LogMAR, improving significantly after 1, 3, 6 and 12 months (all p < 0.05 vs. baseline). The mean baseline central macular thickness (CMT) was 429 ± 110 μm, improving significantly after 1, 3, 6 and 12 months (all p < 0.05 vs. baseline). Five eyes (19.2%) developed ocular hypertension during the follow-up, requiring initiation or strengthening of intraocular pressure lowering medication. The majority of eyes (77%) did not require any rescue DEXi during the available 12-month follow-up. The resolution of UME after DEXi seemed to predict the anatomical response after FAi. The baseline presence of a disorganization of the inner retinal layers (DRIL) and hyperreflective foci (HRF) were both associated with a higher likelihood of requiring rescue DEXi injections. Conclusion: FAi implantation led to a significant BCVA and CMT improvement with a good safety profile over the 12-month follow-up. Predictive factors of treatment outcomes seem to include the anatomical response to DEXi and the presence of DRIL and HRF at baseline.
Uncommon Carotid Artery Stenting Complications: A Series by Images
Authors: Vadalà Giuseppe , Sucato Vincenzo , Costa Francesco , Castriota Fausto , Nerla Roberto , Roscitano Giuseppe , Versace Antonio Giovanni , Galassi Alfredo Ruggero , Micari Antonio
Published: February 2024

Aims: To describe through emblematic images rare but clinically relevant carotid artery stenting complications that occurred at two high-volume centres for carotid artery stenting (CAS). Background: CAS is an alternative to carotid endarterectomy (CEA) for the treatment of carotid artery stenosis in patients judged to be at high risk for CEA. CAS complications range between 1 and 9% and are higher in older patients complaining of neurological symptoms at the time of presentation. Besides periprocedural or early-after-procedure stroke, which remains the true Achilles’ heel of CAS, other dramatic complications might compromise the clinical outcomes of this procedure. Methods: Five infrequent complications, out of more than 1000 CAS performed in the years 2016–2021, have been described. Results: Among CAS complications, acute carotid stent thrombosis, rescue retrieval of a disconnected distal cerebral embolic protection device, plaque prolapse after carotid stenting, cerebral hyperperfusion syndrome (CHS), and radial artery long sheath entrapment requiring surgical intervention were found to account for 0.3% of the total number of procedures performed by operators with high CAS volume. Conclusions: Unusual CAS complications may infrequently occur, even in hands of expert operators. To know how to deal with such complications might help interventionalists to improve CAS performance.
Spatial Patterns, Drivers, and Sustainable Utilization of Terrace Abandonment in Mountainous Areas of Southwest China
Authors: Ren Weiying , Yang Aoxi , Wang Yahui
Published: February 2024

Sloping farmland abandonment has become a typical land use pattern worldwide. Along with the aggravation of sloping farmland abandonment, terrace abandonment is also showing an increasing trend. Systematically clarifying the pattern and mechanism of terrace abandonment is a prerequisite for effective management. Based on the survey data of 145 villages, 697 rural households, and satellite remote sensing in Southwest China, this study uses spatial analysis and the Logit model to reveal the scale, pattern, and driving mechanism of terrace abandonment in the study area to provide scientific references for the sustainable utilization of terrace resources in mountainous areas. This study found that in the study area, 63% of the villages had experienced terrace abandonment, and nearly one-fifth of the rural households had abandoned terraces. The area of abandoned terraces accounted for 7.65% of the total area, and the scale of abandoned terraces reached 449,360 hectares, of which Chongqing has the highest proportion of terrace abandonment (11.5%), while Yunnan Province has the lowest (5.1%); the overall abandoned terraces show a pattern of higher in the east and lower in the west. Terrace abandonment is influenced by multiple factors. The rise in non-agricultural wages attracts rural labor migration as an external force, while the rising operating costs of mountain agriculture serve as internal drivers. Under the combined influence of internal and external factors, the abandonment of terraces in southwest mountainous areas is intensifying. The government should actively conduct assessments of terrace resources within the region and implement targeted measures to address terrace abandonment.
The Mechanism of Street Markets Fostering Supportive Communities in Old Urban Districts: A Case Study of Sham Shui Po, Hong Kong
Authors: Tan Yueyi , Song Jusheng , Yu Lei , Bai Yunxi , Zhang Jianfeng , Chan Man-Ha (Sylvia) , van Ameijde Jeroen van
Published: February 2024

In old urban districts with tenement buildings, street markets address the working class’s social and economic needs. They are pivotal in fostering supportive communities, in particular for low-income residents in sub-standard housing. However, their outdated overall environment impedes the delivery of adequate support to residents. Prior research on street markets has focused on those in the Americas and Europe, and has revealed the societal support values of these markets. However, studies on street markets in high-density cities like Hong Kong are lacking. This study introduces an evaluation framework to assess the impact of street markets on the development of supportive communities for Hong Kong’s sub-divided apartment residents. Employing the Pei Ho Street market in Sham Shui Po as a case study, an importance-performance analysis highlights critical but underperforming factors including public facilities, activity venues, commerce, and employment. Based on these findings, the study proposes four improvement strategies for the renewal of street markets in high-density communities, which could apply to other cities with similar high-density urban environments. It concludes that street markets in Hong Kong display unique spatial characteristics shaped by low-income lifestyles in a high-density urban environment, enriching daily social life and promoting sustainable community development.
Study on the Coupling Coordination Development between the Digital Economy and Innovation Efficiency: Evidence from the Urban Agglomeration in the Middle Reaches of the Yangtze River
Authors: Jiang Min , Yang Shuwang , Zhou Guohua
Published: February 2024

The urban agglomeration in the middle reaches of the Yangtze River holds a crucial strategic position in China’s economic and social development landscape. Exploring the coordinated development effects within the digital economy and innovation in this area is conducive to promoting the development of the central region of China and the Yangtze River Economic Belt. This paper uses the 28 sample cities in urban agglomeration in the middle reaches of the Yangtze River as the study sample, and constructs a digital economy indicator system and an urban innovation efficiency indicator system. Based on the coupling coordination degree model, we use kernel density estimation, the Markov chain algorithm, and the Dagum Gini coefficient decomposition method to empirically investigate the dynamic trends in coupling coordination development between the digital economy and urban innovation efficiency from 2012 to 2021. The research results reveal an overall upward trend in the digital economy, innovation efficiency, and coupling coordination development stages. However, the upward trend is accompanied by the risk of recession. Moreover, there are significant differences between cities, as highlighted by the differences between Wuhan and other cities. In the light of the findings, it is recommended that government departments take measures, including being alert to the risk of regressive development, developing cities in a realistic manner, and drawing on the experiences of outstanding cities in development. This research can provide new insights and empirical references for government entities to take measures for a more coordinated development of the digital economy and innovation efficiency in the urban agglomeration in the middle reaches of the Yangtze River.
Can a Crop Rotation and Fallow System Reduce the Carbon Emission Intensity of Agriculture?
Authors: Zhang Xuefeng , Sun Hui , Xia Xuechao , Yang Zedong , Zhu Shusen
Published: February 2024

Under the carbon emission pattern of “peak carbon and carbon neutrality”, the policy of crop rotation and fallow system (CRFS) is regarded as an important initiative to promote the green, low-carbon, and high-quality development of agriculture. Focusing on balanced panel data from 30 provinces in China from 2010 to 2021, this paper empirically examines the impact of CRFS on agricultural carbon emissions (ACEI) and its internal mechanism using a multi-temporal difference-in-differences model. The benchmark regression results show that CRFS can significantly reduce ACEI, and the results remain robust after validation by multiple methods. Mechanism results show that CRFS is able to reduce ACEI by reducing factor mismatch and promoting the level of agricultural services. Heterogeneity analysis results show that the arable land fallow rotation system is more conducive to promoting the reduction in agricultural carbon emission intensity in the main grain producing areas, main grain marketing areas, high land transfer areas, and plantation areas than in the grain production and marketing balanced areas, low land transfer, and animal husbandry areas. This study demonstrates the effectiveness of the CRFS policy implementation, provides a doctrinal basis for expanding the scope of CRFS implementation, and provides policy recommendations for relevant departments to improve the CRFS policy.
Taste and Smell Disorders: A Critical Look at Olfactory and Gustatory Dysfunction
Authors: Maniaci Antonino , Lechien Jérome R. , Vaira Luigi Angelo , La Via Luigi
Published: February 2024

In an era where modern medicine has made remarkable advances in managing diseases in the head and neck region, we present this Special Issue to provide a spotlight on the new research advances on olfactory and gustatory disorders [...]
Pulmonary Hypertension and Hypothyroidism—Still an Important Clinical Coincidence in Paediatric Population, an Endocrinologist’s Point of View
Authors: Lecka-Ambroziak Agnieszka , Kot Karolina
Published: February 2024

There is limited data on hypotheses linking autoimmune thyroid diseases (AITD) and hypothyroidism with pulmonary hypertension (PH). Moreover, the prevalence of this coincidence, as well as the possible common pathogenic mechanisms, are even less explicit in paediatric population. We present a review of recently published articles regarding relatively large cohorts of children with PH, coming from paediatric PH registries, aiming to clarify the coincidence of PH and AITD, especially hypothyroidism, and discuss its possible mutual impact. Although thyroid disorders have been excluded from the latest PH classification, it is still important to remember the possibility of this coincidence as it may significantly influence patients’ clinical outcome. Moreover, children with PH may need multidisciplinary care due to the relatively frequent coexistence with not only hormonal abnormalities but also growth impairment, genetic disorders, and mental delay. Further specific paediatric studies are needed to improve the care in this rare disease, especially in patients with other comorbidities present.
Simulation Analysis and Experimental Research on Electric Thermal Coupling of Current Bearing
Authors: Wang Zhiwei , Mao Shuanglong , Tian Heng , Su Bing , Cui Yongcun
Published: February 2024

With the advancement of industries such as high-speed railways, new energy vehicles, and wind power, bearings are frequently exposed to various electric field environments, leading to the need for lubricating oil films of bearings to withstand voltage. One of the major issues caused by the breakdown discharge process of the lubricating oil film in bearings is the generation of local instantaneous high temperatures. This temperature rise is a key factor contributing to problems such as high operating temperature of bearings, surface damage in the contact area, and degradation of lubrication performance. This research article focuses on the comprehensive influence of bearing friction and electrical factors. It establishes a heat source calculation model and a temperature field simulation model specifically for current-carrying bearings. This study analyzes both the overall temperature rise of bearings and the local temperature rise resulting from breakdown discharge. Furthermore, the accuracy of the simulation analysis is verified through experiments. The temperature field simulation and experimental results consistently indicate that electrical environmental factors can cause an increase in the overall temperature rise of a bearing. Additionally, the breakdown and discharge of the lubricating oil film generate local instantaneous high temperatures in the contact area of the bearing.
Preparation of Aminated Sodium Lignosulfonate and Efficient Adsorption of Methyl Blue Dye
Authors: Huo Li-Zhu , Guo Chao-Fei , Gong Zhu-Xiang , Xu Hao , Yang Xue-Juan , Wang Yu-Xuan , Luo Xi-Ping
Published: February 2024

The aminated sodium lignosulfonate (AELS) was prepared through a Mannich reaction and characterized via FT-IR, TG, SEM and XPS in this study. Subsequently, the adsorption capacity of AELS for methyl blue (MB) was evaluated under various conditions such as pH, adsorbent dosage, contact time, initial concentration and temperature. The adsorption kinetics, isotherms and thermodynamics of AELS for methyl blue were investigated and analyzed. The results were found to closely adhere to the pseudo-second-order kinetic model and Langmuir isotherm model, suggesting a single-molecular-layer adsorption process. Notably, the maximum adsorption capacity of AELS for methyl blue (153.42 mg g−1) was achieved under the specified conditions (T = 298 K, MAELS = 0.01 g, pH = 6, VMB = 25 mL, C0 = 300 mg L−1). The adsorption process was determined to be spontaneous and endothermic. Following five adsorption cycles, the adsorption capacity exhibited a minimal reduction from 118.99 mg g−1 to 114.33 mg g−1, indicating good stability. This study contributes to the advancement of utilizing natural resources effectively and sustainably.
Electro-Mechanical Characterisation and Damage Monitoring by Acoustic Emission of 3D-Printed CB/PLA
Authors: Roumy Laurane , Truong-Hoang Thuy-Quynh , Touchard Fabienne , Robert Colin , Martinez-Hergueta Francisca
Published: February 2024

Even though the influence of the printing direction on the mechanical properties of 3D-printed samples by fused filament fabrication is established in the literature, very little is known about mechanical and electrical coupling. In this study, electrically conductive polylactic acid filled with carbon black particles undergoes monotonic and repeated progressive tensile loading to better understand the influence of the printing direction on the electro-mechanical properties of three-dimensional-printed samples. The objective is to analyse the electro-mechanical behaviour of this composite for its potential application as an actuator. The classical laminate theory is also applied to evaluate the relevance of this theory in predicting the mechanical characteristics of this material. In addition, a comprehensive damage analysis is performed using acoustic emission, infrared thermography, scanning electron microscopy, and X-ray microcomputed tomography imaging. Results show that the degradation of the mechanical and electrical properties is highly influenced by the printing direction. The appearance and development of crazes in 0° filaments are highlighted and quantified. The conclusions drawn by this study underline the interest in using longitudinal and unidirectional printing directions to improve the conductive path within the samples. Furthermore, the evolution of the resistance throughout the experiments emphasizes the need to control the implemented voltage in the design of future electro-thermally triggered actuators.
The Influence of Contemporary Denture Base Fabrication Methods on Residual Monomer Content, Flexural Strength and Microhardness
Authors: Vuksic Josip , Pilipovic Ana , Poklepovic Pericic Tina , Kranjcic Josip
Published: February 2024

(1) Background: Digital technologies are available for denture base fabrication, but there is a lack of scientific data on the mechanical and chemical properties of the materials produced in this way. Therefore, the aim of this study was to investigate the residual monomer content, flexural strength and microhardness of denture base materials as well as correlations between investigated parameters. (2) Methods: Seven denture base materials were used: one conventional heat cured polymethyl methacrylate, one polyamide, three subtractive manufactured materials and two additive manufactured materials. High-performance liquid chromatography was used to determine residual monomer content and the test was carried out in accordance with the specification ISO No. 20795-1:2013. Flexural strength was also determined according to the specification ISO No. 20795-1:2013. The Vickers method was used to investigate microhardness. A one-way ANOVA with a Bonferroni post-hoc test was used for the statistical analysis. The Pearson correlation test was used for the correlation analysis. (3) Results: There was a statistically significant difference between the values of residual monomer content of the different denture base materials (p < 0.05). Anaxdent pink blank showed the highest value of 3.2% mass fraction, while Polident pink CAD-CAM showed the lowest value of 0.05% mass fraction. The difference between the flexural strength values of the different denture base materials was statistically significant (p < 0.05), with values ranging from 62.57 megapascals (MPa) to 103.33 MPa. The difference between the microhardness values for the different denture base materials was statistically significant (p < 0.05), and the values obtained ranged from 10.61 to 22.86 Vickers hardness number (VHN). A correlation was found between some results for the material properties investigated (p < 0.05). (4) Conclusions: The selection of contemporary digital denture base manufacturing techniques may affect residual monomer content, flexural strength and microhardness but is not the only criterion for achieving favourable properties.
Influence of Exposure to a Wet Atmosphere on the UV-Sensing Characteristics of ZnO Nanorod Arrays
Authors: Evstafieva Maria , Redkin Arcady , Roshchupkin Dmitry , Rudneva Tatyana , Yakimov Eugene
Published: February 2024

Zinc oxide is a promising material for the creation of various types of sensors, in particular UV detectors. In this work, arrays of ordered nanorods were grown by chemical vapor deposition. The effect of environmental humidity on the sensing properties of zinc oxide nanorod arrays was investigated, and a prototype UV sensor using indium as an ohmic contact was developed. UV photoresponses were measured for the samples stored in dry and wet atmospheres. The increase in sensitivity and response of the ZnO nanorod arrays was observed after prolonged exposure to a wet atmosphere. A model was proposed to explain this effect. This is due to the formation of hydroxyl groups on the surface of zinc oxide nanorods, which is confirmed by FTIR spectroscopy data. For the first time, it has been shown that after storage in a wet atmosphere, the sensory properties of the structure remain stable regardless of the ambient humidity.
Study on the Effect of Polyamine Water Treatment Agent on Metal Corrosion Inhibition in Boiler Steam–Water System
Authors: Zhao Zhijuan , Cao Bingqing , Zhao Bo , Chen Sheng , Jin Dong
Published: February 2024

A polyamine water treatment agent was prepared with the film-forming amine (N-oleyl-1,3-propylenediamine) and the neutralizing amine (cyclohexanamine) under optimal conditions. The copper sulfate liquid drop experiment showed that a protective film was formed by the polyamine water treatment agent on carbon steel. The analyses of the polarization curve and electrochemical impedance spectroscopy of carbon steel indicated that the polyamine water treatment agent exhibited geometric effects, which could inhibit both anode and cathode reactions of carbon steel, and the corrosion inhibition effect of the polyamine water treatment agent showed an extreme-concentration phenomenon. A metal corrosion experiment in a simulated boiler steam–water system indicated that the polyamine water treatment agent mitigated the corrosion of carbon steel at different temperatures, and the corrosion inhibition rates of the polyamine water treatment agent in liquid and gas environments at 150 °C were 53.84% and 67.43%, respectively, better than that at 350 °C. SEM-EDS characterization indicated that the formation of the corrosion product, iron oxide, on the carbon steel was reduced with the addition of the polyamine water treatment agent in the simulated boiler steam–water system.
Effect of Low-Temperature Oxygen Plasma Treatment of Titanium Alloy Surface on Tannic Acid Coating Deposition
Authors: Winiecki Mariusz , Stepczyńska Magdalena , Moraczewski Krzysztof , Skowronski Lukasz , Trzcinski Marek , Rerek Tomasz , Malinowski Rafał
Published: February 2024

In this study, the effect of low-temperature oxygen plasma treatment with various powers of a titanium alloy surface on the structural and morphological properties of a substrate and the deposition of a tannic acid coating was investigated. The surface characteristics of the titanium alloy were evaluated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle measurements. Following this, the tannic acid coatings were deposited on the titanium alloy substrates and the structural and morphological properties of the tannic acid coatings deposited were subject to characterization by XPS, SEM, and spectroscopic ellipsometry (SE) measurements. The results show that the low-temperature oxygen plasma treatment of titanium alloys leads to the formation of titanium dioxides that contain –OH groups on the surface being accompanied by a reduction in carbon, which imparts hydrophilicity to the titanium substrate, and the effect increases with the applied plasma power. The performed titanium alloy substrate modification translates into the quality of the deposited tannic acid coating standing out by higher uniformity of the coating, lower number of defects indicating delamination or incomplete bonding of the coating with the substrate, lower number of cracks, thinner cracks, and higher thickness of the tannic acid coatings compared to the non-treated titanium alloy substrate. A similar effect is observed as the applied plasma power increases.
Process Study of Selective Laser Sintering of PS/GF/HGM Composites
Authors: Liu Lijian , Zhu Shouxiao , Zhang Yongkang , Ma Shaobo , Wu Shuxuan , Wei Bin , Yang Guang
Published: February 2024

To address the issues of insufficient strength and poor precision in polystyrene forming parts during the selective laser sintering process, a ternary composite of polystyrene/glass fiber/hollow glass microbeads was prepared through co-modification by incorporating glass fiber and hollow glass microbeads into polystyrene using a mechanical mixing method. The bending strength and dimensional accuracy of the sintered composites were investigated by conducting an orthogonal test and analysis of variance to study the effects of laser power, scanning speed, scanning spacing, and delamination thickness. The process parameters were optimized and selected to determine the optimal combination. The results demonstrated that when considering bending strength and Z-dimensional accuracy as evaluation criteria for terpolymer sintered parts, the optimum process parameters are as follows: laser power of 24 W, scanning speed of 1600 mm/s, scanning spacing of 0.24 mm, and delamination thickness of 0.22 mm. Under these optimal process parameters, the bending strength of sintered parts reaches 6.12 MPa with a relative error in the Z-dimension of only 0.87%. The bending strength of pure polystyrene sintered parts is enhanced by 15.69% under the same conditions, while the relative error in the Z-dimension is reduced by 63.45%. It improves the forming strength and precision of polystyrene in the selective laser sintering process and achieves the effect of enhancement and modification, which provides a reference and a new direction for exploring polystyrene-based high-performance composites and expands the application scope of selective laser sintering technology.
Research on Utilizable Calcium from Calcium Carbide Slag with Different Extractors and Its Effect on CO2 Mineralization
Authors: Ma Yantao , Zhang Xiang , Du Zhengyu , Hou Haobo , Zheng Yiguang
Published: February 2024

With the increasing accumulation of alkaline industrial solid waste, the mineralization of CO2 using alkaline industrial solid waste has broad application prospects. Carbide slag is highly alkaline and contains a large amount of calcium elements, making it an excellent material for CO2 mineralization. Our idea was to acquire qualified products and fast kinetics by integrating carbide slag utilization and carbon reduction. The reaction route was divided into two steps: calcium extraction and carbonization. In order to achieve efficient extraction of utilizable calcium, we selected NH4Ac as the extraction agent, which has the advantage of buffer protection and environmental friendliness due to being an acetate radical. The extraction efficiency of utilizable calcium exceeded 90% under the conditions of L/S 20:1 and NH4+/Ca2+ 2:1. In the carbonization process, the crystal forms of CaCO3 synthesized by direct carbonation, acid extraction, and ammonium salt were characterized. The formation mechanism of vaterite in ammonium solution and the influence of impurities (Al3+, Mg2+) on the crystal transformation were revealed. This study provides technical support for using alkaline industrial waste to prepare high-purity vaterite. Therefore, alkaline industrial waste can be efficiently and sustainably utilized through CO2 mineralization.
Study on Forming Mechanism of the Recast Layer on the Workpiece Surface during Micro EDM
Authors: Wang Chunmei , Wang Hao , Chu Xuyang , Lu Yunxiang , He Haifeng
Published: February 2024

In comparison to conventional EDM, micro EDM distinguishes itself through its brief discharge duration, narrow discharge channel radius, and concentrated energy density. However, there remains a paucity of comprehensive research on the surface formation characteristics in this domain. This paper delves into the formation mechanism of the recast layer in micro EDM workpieces, scrutinizing the primary factors that influence the formation process and the morphological attributes of the recast layer. We conducted a series of single-pulse experiments and micro EDM trials. Utilizing surface fitting tools, our experimental findings facilitated the derivation of a relational expression between the recast layer thickness of high-speed steel and the discharge parameters in micro EDM. Notably, when the energy is below 100 μJ, the recast layer thickness remains under 10 μm. Specifically, at an energy level of 16 μJ, opting for a smaller capacitance of 2200 pf and a higher voltage of 120 V in micro EDM results in a thinner recast layer. This study serves as a cornerstone for future efforts aimed at controlling and assessing the surface morphology of micro EDM.
Plasticity-Induced Heating: Revisiting the Energy-Based Variational Model
Authors: Hartmann Christoph , Obermeyer Michael
Published: February 2024

Temperature evolution during plastic deformation is of great importance for the design of manufacturing processes, as well as for the analysis and prediction of tool wear. However, the results from experimental- and numerical-type research are still often contradictory. In this paper, we analyze methods for estimating plasticity-induced heating directly from displacement fields that can be recorded during experiments or extracted from simulation results. In terms of computational methodology, the thermodynamically motivated energy-based variational formulation of the coupled thermo-mechanical boundary-value problem is adapted to the problem at hand. Since an analysis of this variational formulation exhibits challenges and distinct inconsistencies with respect to the problem at hand, an alternative approach is proposed. This alternative approach is essentially a purely thermal finite element simulation, and it is conducted using a heat source term that is empirically based on the fraction of irreversible deformation work converted to heat. Our approach estimates plasticity-induced heating based on the strain and strain rate data derived from displacement fields. We therefore incorporate thermo-visco-plastic constitutive behavior (Johnson–Cook) with a thermodynamically motivated model that specifies the fraction of plastic work converted to heat (the Taylor–Quinney coefficient).
Assembly Function Recognition in Embedded Systems as an Optimization Problem
Authors: Avitan Matan , Ravve Elena V. , Volkovich Zeev
Published: February 2024

Many different aspects of software system development and verification rely on precise function identification in binary code. Recognition of the source Assembly functions in embedded systems is one of the fundamental challenges in binary program analysis. While numerous approaches assume that the functions are given a priori, correct identification of the functions in binaries remains a great issue. This contribution addresses the problem of uncertainty in binary code in identification of functions, which were optimized during compilation. This paper investigates the difference between debug and optimized functions via modeling of these functions. To do so, we introduce an extensible model-centred hands-on approach for examining similarities between binary functions. The main idea is to model each function using a set of predetermined, experimentally discovered features, and then find a suitable weight vector that could give impact factor to each such a feature. After finding the weight vector, the introduced models of such desired functions can be identified in binary software packages. It means that we reduce the similarity identification problem of the models to a classical version of optimization problems with one optimization criterion. Using our implementation, we found that the proposed approach works smoothly for functions, which contain at least ten Assembly instructions. Our tool guarantees success at a very high level.
Energy Management for Hybrid Electric Vehicles Using Safe Hybrid-Action Reinforcement Learning
Authors: Xu Jinming , Lin Yuan
Published: February 2024

Reinforcement learning has shown success in solving complex control problems, yet safety remains paramount in engineering applications like energy management systems (EMS), particularly in hybrid electric vehicles (HEVs). An effective EMS is crucial for coordinating power flow while ensuring safety, such as maintaining the battery state of charge within safe limits, which presents a challenging task. Traditional reinforcement learning struggles with safety constraints, and the penalty method often leads to suboptimal performance. This study introduces Lagrangian-based parameterized soft actor–critic (PASACLag), a novel safe hybrid-action reinforcement learning algorithm for HEV energy management. PASACLag utilizes a unique composite action representation to handle continuous actions (e.g., engine torque) and discrete actions (e.g., gear shift and clutch engagement) concurrently. It integrates a Lagrangian method to separately address control objectives and constraints, simplifying the reward function and enhancing safety. We evaluate PASACLag’s performance using the World Harmonized Vehicle Cycle (901 s), with a generalization analysis of four different cycles. The results indicate that PASACLag achieves a less than 10% increase in fuel consumption compared to dynamic programming. Moreover, PASACLag surpasses PASAC, an unsafe counterpart using penalty methods, in fuel economy and constraint satisfaction metrics during generalization. These findings highlight PASACLag’s effectiveness in acquiring complex EMS for control within a hybrid action space while prioritizing safety.
Event-Triggered Relearning Modeling Method for Stochastic System with Non-Stationary Variable Operating Conditions
Authors: Liu Jiyan , Zhang Yong , Zhou Yuyang , Chen Jing
Published: February 2024

This study presents a novel event-triggered relearning framework for neural network modeling, designed to improve prediction precision in dynamic stochastic complex industrial systems under non-stationary and variable conditions. Firstly, a sliding window algorithm combined with entropy is applied to divide the input and output datasets across different operational conditions, establishing clear data boundaries. Following this, the prediction errors derived from the neural network under different operational states are harnessed to define a set of event-triggered relearning criteria. Once these conditions are triggered, the relevant dataset is used to recalibrate the model to the specific operational condition and predict the data under this operating condition. When the predicted data fall within the training input range of a pre-trained model, we switch to that model for immediate prediction. Compared with the conventional BP neural network model and random vector functional-link network, the proposed model can produce a better estimation accuracy and reduce computation costs. Finally, the effectiveness of our proposed method is validated through numerical simulation tests using nonlinear Hammerstein models with Gaussian noise, reflecting complex stochastic industrial processes.