bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathogenesis and Surgical Treatment of Dextro-Transposition of the Great Arteries (D-TGA): Part II
Authors: Zubrzycki Marek , Schramm Rene , Costard-Jäckle Angelika , Morshuis Michiel , Gummert Jan F. , Zubrzycka Maria
Published: August 2024

Dextro-transposition of the great arteries (D-TGA) is the second most common cyanotic heart disease, accounting for 5–7% of all congenital heart defects (CHDs). It is characterized by ventriculoarterial (VA) connection discordance, atrioventricular (AV) concordance, and a parallel relationship with D-TGA. As a result, the pulmonary and systemic circulations are separated [the morphological right ventricle (RV) is connected to the aorta and the morphological left ventricle (LV) is connected to the pulmonary artery]. This anomaly is included in the group of developmental disorders of embryonic heart conotruncal irregularities, and their pathogenesis is multifactorial. The anomaly’s development is influenced by genetic, epigenetic, and environmental factors. It can occur either as an isolated anomaly, or in association with other cardiac defects. The typical concomitant cardiac anomalies that may occur in patients with D-TGA include ventriculoseptal defects, patent ductus arteriosus, left ventricular outflow tract obstruction (LVOTO), mitral and tricuspid valve abnormalities, and coronary artery variations. Correction of the defect during infancy is the preferred treatment for D-TGA. Balloon atrial septostomy (BAS) is necessary prior to the operation. The recommended surgical correction methods include arterial switch operation (ASO) and atrial switch operation (AtrSR), as well as the Rastelli and Nikaidoh procedures. The most common postoperative complications include coronary artery stenosis, neoaortic root dilation, neoaortic insufficiency and neopulmonic stenosis, right ventricular (RV) outflow tract obstruction (RVOTO), left ventricular (LV) dysfunction, arrhythmias, and heart failure. Early diagnosis and treatment of D-TGA is paramount to the prognosis of the patient. Improved surgical techniques have made it possible for patients with D-TGA to survive into adulthood.
Prediction Analysis of Sea Level Change in the China Adjacent Seas Based on Singular Spectrum Analysis and Long Short-Term Memory Network
Authors: Xie Yidong , Zhou Shijian , Wang Fengwei
Published: August 2024

Considering the nonlinear and non-stationary characteristics of sea-level-change time series, this study focuses on enhancing the predictive accuracy of sea level change. The adjacent seas of China are selected as the research area, and the study integrates singular spectrum analysis (SSA) with long short-term memory (LSTM) neural networks to establish an SSA-LSTM hybrid model for predicting sea level change based on sea level anomaly datasets from 1993 to 2021. Comparative analyses are conducted between the SSA-LSTM hybrid model and singular LSTM neural network model, as well as (empirical mode decomposition) EMD-LSTM and (Complete Ensemble Empirical Mode Decomposition with Adaptive Noise) CEEMDAN-LSTM hybrid models. Evaluation metrics, including the root mean square error (RMSE), mean absolute error (MAE), and the coefficient of determination (R2), are employed for the accuracy assessment. The results demonstrate a significant improvement in prediction accuracy using the SSA-LSTM hybrid model, with an RMSE of 5.26 mm, MAE of 4.27 mm, and R2 of 0.98, all surpassing those of the other models. Therefore, it is reasonable to conclude that the SSA-LSTM hybrid model can more accurately predict sea level change.
Ecology of Intertidal Rocky Shores Related to Examples of Coastal Geology across Phanerozoic Time
Authors: Johnson Markes E.
Published: August 2024

The boundary between land and sea is among the most extensive and extreme ecological barriers on planet Earth. Intertidal organisms living at this junction are subject to potentially lethal conditions related to desiccation, temperature fluctuations, and wave shock. Although difficult to quantify at a global level, rocky coasts account for between a third and three-quarters of all shorelines today. Resistant to coastal erosion, rocky coasts also exhibit adaptations by marine invertebrates and marine algae within intertidal zones that are geographically widespread. Biotic composition is variable depending on the tidal range at any given place and on climatic differences between tropical and more temperate latitudes. Contemporary granite shores having low recession rates with well-established biotic zones are reviewed in three regions: Mount Desert Island in Maine, USA (44° N latitude), Mahé and Praslin islands in Seychelles (4°30′ S Latitude), and Lizard Island off the coast of Queensland, Australia (14°40′ S Latitude). The zonal composition and overall biotic diversity at these locations are compared, as well as the fossilization potential of key biota. Over the Phanerozoic time period during the last 538 million years, the ratio between land and ocean varied as a function of plate tectonics depending on the maximum dispersal or coalescence of continents and on relative changes in global sea level. Fossil biotas from a dozen paleoislands with dominant rocky shores that range from 485 million to 125,000 years in age are reviewed to show diversification through time, taking into account episodic mass extinctions. Relationships between storm tracks and volcanic eruptions that factor into physical disruptions are also considered as means of rapid burial and preservation. Themes related to rocky-shore ecology and paleoecology benefit from the cross-fertilization of ideas by marine biologists and marine paleontologists. It is hoped this review may attract a cohort of new students to these allied fields of study, especially in Asia, Africa, and South America.
Accuracy of Bathymetric Depth Change Maps Using Multi-Temporal Images and Machine Learning
Authors: Lowell Kim , Hermann Joan
Published: August 2024

Most work to date on satellite-derived bathymetry (SDB) depth change estimates water depth at individual times t1 and t2 using two separate models and then differences the model estimates. An alternative approach is explored in this study: a multi-temporal Sentinel-2 image is created by “stacking” the bands of the times t1 and t2 images, geographically coincident reference data for times t1 and t2 allow for “true” depth change to be calculated for the pixels of the multi-temporal image, and this information is used to fit a single model that estimates depth change directly rather than indirectly as in the model-differencing approach. The multi-temporal image approach reduced the depth change RMSE by about 30%. The machine learning modelling method (categorical boosting) outperformed linear regression. Overfitting of models was limited even for the CatBoost models having the maximum number of variables examined. The visible Sentinel-2 spectral bands contributed most to the model predictions. Though the multi-temporal stacked image approach produced clearly superior depth change estimates compared to the conventional approach, it is limited only to those areas for which geographically coincident multi-temporal reference/“true” depth data exist.
Nonlinear Buckling of Flexible Pipe Carcass Considering Residual Stress Due to Deformation
Authors: Tang Minggang , Guo Zepeng , Zheng Wenhui , Wu Fanlei
Published: August 2024

Flexible pipe is one of the most important types of equipment applied in the deep-water development of oil and gas and deep-sea metal mining. The carcass of an unbonded flexible pipe with a typical interlocked structure prevents buckling failure under external hydrostatic pressure. The process and principle of carcass layer deformation are described, and a three-dimensional finite element model with solid-shell elements is developed to simulate the cold forming process of a metal strap subjected to a series of rollers. The deflection and deformation behavior in the bend-rolling and interlocking process are investigated, and the residual stress due to deformation is calculated. Taking the carcass layer of a 4-inch internal diameter flexible pipe as an example, a three-dimensional finite element model of the carcass layer loaded with external hydrostatic pressure is developed. The buckling collapse of the carcass layer is evaluated considering different initial imperfections, including residual stress. The results show that the critical pressure can be 60% less than under ideal conditions when the geometric imperfection, material nonlinearity and residual stress due to deformation are considered, which indicates that the effect of residual stress on buckling collapse cannot be ignored. The numerical model and results provide an efficient method and basis for nonlinear buckling analysis and a collapse-resistant unbonded flexible pipe design for industry.
Investigation of North Atlantic Salinity Long-Term Trends Based on Historical Datasets
Authors: Sukhonos Pavel , Gusev Anatoly , Diansky Nikolay
Published: August 2024

In contrast to fairly good knowledge of seasonal and interannual variability in North Atlantic salinity, its long-term historical changes remain poorly characterized, making it difficult to assess the current state and possible future changes. To fill this gap, we present the results of applying a non-parametric method of regression analysis (quantile regression) to assess long-term changes in North Atlantic salinity (0°–70° N, 8°–80° W) based on multiple datasets. The features of quantile trends in monthly salinity for a median value in two periods (1948–2018 and 1961–2011) are considered. In 1948–2018, salinization was generally detected in North Atlantic tropical and subtropical latitudes, while desalination was found in subpolar latitudes. For the 71-year period under consideration, the median monthly salinity in subtropical latitudes increased by 0.07±0.02 PSU. Over the period 1961–2011, pronounced long-term changes in the North Atlantic salinity are difficult to identify based on the datasets used. A consistency analysis of significant salinity trends across the most used datasets allowed us to detect five small areas with pronounced positive trends in the upper ocean salinity. These include the Guiana Current, the vicinity of 12° N, 48° W, the Canary upwelling area, the region of the Gulf Stream transition to the North Atlantic Current and the western part of the North Atlantic Subpolar Gyre. In these areas, over a 51-year period, salinity in the 10–400 m layer increased by an average of 0.10±0.04 PSU.
Spatial Interaction and Driving Factors between Urban Land Expansion and Population Change in China
Authors: Meng Hao , Liu Qianming , Yang Jun , Li Jianbao , Chuai Xiaowei , Huang Xianjin
Published: August 2024

The rational matching of urban land and population has become an important prerequisite for sustainable urban development. In this paper, the traditional urban land scale elasticity model was improved, and combined with the gravity model, the spatial interaction between land expansion and population change in 618 cities in China during the period 2006–2021 was investigated. The geographical detector method was used to reveal what drives them. The main results were as follows: (1) China’s urban land expansion rate was 1.83 times faster than the population growth rate during 2006–2021. After the implementation of the New-type Urbanisation Plan in 2014, the ratio of land expansion rate to population growth rate dropped from 2.46 to 1.12. (2) Among the six interaction types identified, land rapid expansion is the most significant, accounting for 41.59% of urban samples. (3) The geographical detector method found that the indicators of urban development rights such as the level of administrative hierarchy and the ratio of fiscal revenue to fiscal expenditure were the main factors affecting land expansion and that economic indicators such as gross domestic product and employment opportunities dominated population change. Fortunately, the intervention role of urban development rights has declined, and the constraints of market mechanisms, resources and environment have gradually become the dominant factors in urban land expansion and population change. These findings provide a theoretical basis for alleviating the human–land contradiction and achieving sustainable urban development.
Guardians of the Circassian Heritage Language: Exploring a Teacher’s Agency in the Endeavour of Endangered Language Maintenance
Authors: Schwartz Mila , Shogen Miriam
Published: August 2024

The Circassian language is the heritage language (HL) of a small minority group in Israel. Since its classification as an endangered language around the globe, the focus has been put on effective maintenance programs. Changes in education methods within Circassian communities were inevitable. In Israel, the Circassian Maintenance Program is crucial in primary schools, where formal literacy instruction in the Circassian language begins in fifth grade. This study examined the agentic role of the Circassian literacy teacher in engaging students in learning their heritage language and its maintenance, as expressed in her attitudes, beliefs and knowledge and her classroom strategies. This three-month-long ethnographic data collection was conducted at the teacher’s study centre “Nal” (i.e., a treasure in Circassian). Data was gathered through classroom observations and semi-structured interviews with a Circassian HL teacher to understand her attitudes, beliefs and knowledge and to identify strategies to encourage student engagement in HL learning. In general, the teacher showed expertise in the HL and authentic use of it, as well as cultural and religious competence, adaptability, and flexibility. In addition, she encouraged children’s agency and autonomy and provided individualised support, integration of technology and reflective practice. The results indicated that a sense of identity, unity and belonging to the community are all held together by the pillar of HL knowledge. By engaging her students in translanguaging practices, the teacher promoted their awareness of language patterns, vocabulary and grammar in both Circassian and other languages of their wide linguistic repertoire (Hebrew, Arabic and English).
The Role of Brassinosteroids in Plant Cold Stress Response
Authors: He Zhiqi , Zhou Mengdi , Feng Xiaojie , Di Qinghua , Meng Di , Yu Xianchang , Yan Yan , Sun Mintao , Li Yansu
Published: August 2024

Temperature affects plant growth and geographical distribution. Cold stress occurs when temperatures fall below the physiologically optimal range for plants, causing permanent and irreversible damage to plant growth, development, and production. Brassinosteroids (BRs) are steroid hormones that play an important role in plant growth and various stress responses. Recent studies have shown that low temperatures affect BR biosynthesis in many plant species and that BR signaling is involved in the regulation of plant tolerance to low temperatures, both in the CBF-dependent and CBF-independent pathways. These two regulatory pathways correspond to transient and acclimation responses of low temperature, respectively. The crosstalk between BRs and other hormones is a significant factor in low-temperature tolerance. We provide an overview of recent developments in our knowledge of BRs’ function in plant responses to cold stress and how they interact with other plant hormones in this review.
Gut Microbiota in the Progression of Type 2 Diabetes and the Potential Role of Exercise: A Critical Review
Authors: Deli Chariklia K. , Fatouros Ioannis G. , Poulios Athanasios , Liakou Christina A. , Draganidis Dimitrios , Papanikolaou Konstantinos , Rosvoglou Anastasia , Gatsas Athanasios , Georgakouli Kalliopi , Tsimeas Panagiotis , Jamurtas Athanasios Z.
Published: August 2024

Type 2 diabetes (T2D) is the predominant metabolic epidemic posing a major threat to global health. Growing evidence indicates that gut microbiota (GM) may critically influence the progression from normal glucose tolerance, to pre-diabetes, to T2D. On the other hand, regular exercise contributes to the prevention and/or treatment of the disease, and evidence suggests that a possible way regular exercise favorably affects T2D is by altering GM composition toward health-promoting bacteria. However, research regarding this potential effect of exercise-induced changes of GM on T2D and the associated mechanisms through which these effects are accomplished is limited. This review presents current data regarding the association of GM composition and T2D and the possible critical GM differentiation in the progression from normal glucose, to pre-diabetes, to T2D. Additionally, potential mechanisms through which GM may affect T2D are presented. The effect of exercise on GM composition and function on T2D progression is also discussed.
Material Optimization Method for a Spring-Energized Seal Based on Wear Analysis
Authors: Zhao Xinni , Li Shuangxi , Liu Dengyu , Huang Lele
Published: August 2024

Spring-energized seals demonstrate good sealing performance over a wide range of pressures and temperatures and can compensate for installation eccentricity, high-temperature aging, etc. However, as a contact seal, its polytetrafluoroethylene (PTFE) jacket material is easily worn during the rotation of the end face, which leads to a decline in sealing performance and, ultimately, seal failure. Based on the Archard wear model, a performance prediction model of the spring-energized seal was established by combining tests and numerical analyses. In order to improve the tribological performance of spring-energized seals made of PTFE, varied fillers were added to modify the PTFE, and the tribological and mechanical properties of PTFE composites with varied fillers were measured in experiments. Using a performance prediction model for spring-energized seals, the variation in the friction performance of seals made of these filled PTFEs during the operating cycle was analyzed. The results showed that the performance prediction model can accurately simulate this variation. After a certain amount of wear, the deviation between the simulated data and the experimental data was within ±5%. Compared with spring-energized seals made of pure PTFE, the friction torque of spring-energized seals made of GF/PTFE was reduced by 28.97% at most, and the friction torque reduction rate was lowered by 22.25%.
The Phase Change Heat of Water in the Pore Space of Rocks Based on DSC Studies
Authors: Stępień Piotr , Spychał Edyta , Nartowska Edyta
Published: August 2024

This research investigates the phase change behavior of water within the pore space of Devonian carbonate rock samples using Differential Scanning Calorimetry (DSC) across a temperature range of −80 to 0 °C. This study focuses on dolomite and limestone samples, all with porosities below 3%, an area not extensively covered in previous literature. Significant endothermic effects were observed at temperatures below −2 °C, challenging conventional understanding. The study reveals that the latent heat of phase change in these systems can exceed 334.2 J/g, the known value for bulk water, indicating unique thermodynamic properties of water in confined spaces. For the dolomite rock sample, observed endothermic heat effects below −2 °C were 23.5% and 26.7% of total phase change energy. The cumulative pore volume calculated using the thermoporometry method was found to be higher than expected from water occupancy alone, independent of assumptions about the thickness of the adsorbed unfreezable water layer or pore shape (spherical or cylindrical). This research provides novel insights into unfrozen water content calculations, significantly enhancing frost durability assessments and the geoengineering industry.
Analysis of Chemical Oxygen Demand in Barrel Finishing Based on Reusing Water Resource of Grinding Fluid
Authors: Shi Huiting , Li Xuenan , Yang Shengqiang , Zhao Ruihao , Yuan Xiang
Published: August 2024

To explore the sustainable development of grinding fluid in barrel finishing, the idea of water resource reuse in grinding fluid has been proposed. The influence of the graphene oxide (GO) and the sodium dodecyl benzene sulfonate (SDBS) as main components in the grinding fluid on the chemical oxygen demand (COD) was analyzed. Repreparing new grinding fluids by utilizing the water resources in grinding fluid after finishing will not cause a sharp increase in COD value. GO which absorbs SDBS can be taken away from grinding fluid by physical separation. It will decrease the COD value of grinding fluid. However, SDBS exists in the form of colloids in the grinding fluid and cannot be removed through physical separation, which also affects the COD value. Based on water quality indicators (the COD, pH, total hardness, metal aluminum, anionic surfactants, and total dissolved solids), the water quality index (WQI) of the reusing grinding fluid after finishing by the physical separation is significantly reduced. It indicates that reusing water resources in grinding fluid is a feasible way to reuse grinding fluid.
Simultaneous Necking and Barreling Deformation Behaviors in Bending of Single-Crystal Gold Micro-Cantilever
Authors: Fujita Kazuya , Suzuki Kosuke , Asano Keisuke , Chen Chun-Yi , Kurioka Tomoyuki , Machida Katsuyuki , Ito Hiroyuki , Miyake Yoshihiro , Sone Masato , Chang Tso-Fu Mark
Published: August 2024

Necking and barreling deformation behaviors occurred simultaneously during the bending test of a single-crystal gold micro-cantilever (sample A) with the loading direction parallel to the [1-10] orientation and the neutral plane parallel to the [110] orientation. In contrast, for another single-crystal gold micro-cantilever, sample B, with the loading direction aligned parallel to the [0.37 −0.92 0.05] orientation and the neutral plane parallel to the [0.54 0.28 0.78] orientation, predominant slip band deformation was noted. Sample A exhibited activation of four slip systems, whereas sample B demonstrated activity in only a single-slip system. This difference suggests that the presence of multiple slip systems contributes to the concurrent occurrence of necking and barreling deformations. Furthermore, variations in the thickness of the micro-cantilevers resulted in observable strengthening, indicating that the effect of sample size is intricately linked to the geometry of the cross-section, which we have termed the “sample geometry effect”.
Effects of Rubber Core on the Mechanical Behaviour of the Carbon–Aramid Composite Materials Subjected to Low-Velocity Impact Loading Considering Water Absorption
Authors: Ursache Stefania , Cerbu Camelia , Hadăr Anton , Petrescu Horia Alexandru
Published: August 2024

The large-scale use of composite materials reinforced with carbon–aramid hybrid fabric in various outdoor applications, which ensures increased mechanical resistance including in impact loadings, led to the need to investigate the effects of aggressive environmental factors (moisture absorption, temperature, thermal cycles, ultra-violet rays) on the variation of their mechanical properties. Since the literature is still lacking in research on this topic, this article aims to compare the low-velocity impact behaviour of two carbon–aramid hybrid composite materials (with and without rubber core) and to investigate the effects of water absorption on impact properties. The main objectives of this research were as follows: (i) the investigation of the mechanical behavior in tests for two impact energies of 25 J and 50 J; (ii) comparison of the results obtained in terms of the force, displacement, velocity, and energy related to the time; (iii) analysis of the water absorption data; (iii) low-velocity impact testing of wet specimens after saturation; (iv) comparison between the impact behaviour of the wet specimens with that of the dried ones. One of the main findings was that for the wet specimens without rubber core, absorbed impact energy was 16% less than the one recorded for dried specimens at an impact energy of 50 J. The failure modes of the dried specimens without rubber core are breakage for both carbon and aramid fibres, matrix cracks, and delamination at matrix–fibre interfaces. The degradation for the wet specimens with rubber core is much more pronounced because the decrease in the absorbed impact energy was 53.26% after 10,513 h of immersion in water and all the layers were broken.
Optimization of Dry Sliding Wear in Hot-Pressed Al/B4C Metal Matrix Composites Using Taguchi Method and ANN
Authors: Gajević Sandra , Miladinović Slavica , Güler Onur , Özkaya Serdar , Stojanović Blaža
Published: August 2024

The presented study investigates the effects of weight percentages of boron carbide reinforcement on the wear properties of aluminum alloy composites. Composites were fabricated via ball milling and the hot extrusion process. During the fabrication of composites, B4C content was varied (0, 5, and 10 wt.%), as well as milling time (0, 10, and 20 h). Microstructural observations with SEM microscopy showed that with an increase in milling time, the distribution of B4C particles is more homogeneous without agglomerates, and that an increase in wt.% of B4C results in a more uniform distribution with distinct grain boundaries. Taguchi and ANOVA analyses are applied in order to investigate how parameters like particle content of B4C, normal load, and milling time affect the wear properties of AA2024-based composites. The ANOVA results showed that the most influential parameters on wear loss and coefficient of friction were the content of B4C with 51.35% and the normal load with 45.54%, respectively. An artificial neural network was applied for the prediction of wear loss and the coefficient of friction. Two separate networks were developed, both having an architecture of 3-10-1 and a tansig activation function. By comparing the predicted values with the experimental data, it was demonstrated that the well-trained feed-forward-back propagation ANN model is a powerful tool for predicting the wear behavior of Al2024-B4C composites. The developed models can be used for predicting the properties of Al2024-B4C composite powders produced with different reinforcement ratios and milling times.
Flexible Transparent Films of Oriented Silver Nanowires for a Stretchable Strain Sensor
Authors: Wang Xiaoguang , Song Chengjun , Wang Yangyang , Feng Shaoxuan , Xu Dong , Hao Tingting , Xu Hongbo
Published: August 2024

The potential applications of stretchable strain sensors in wearable electronics have garnered significant attention. However, developing susceptible stretchable strain sensors for practical applications still poses a considerable challenge. The present study introduces a stretchable strain sensor that utilizes silver nanowires (AgNWs) embedded into a polydimethylsiloxane (PDMS) substrate. The AgNWs have high flexibility and electrical conductivity. A stretchable AgNW/Pat-PDMS conductive film was prepared by arranging nanowires on the surface of PDMS using a simple rod coating method. Depending on the orientation angle, the overlap area between nanowires varies, resulting in different levels of separation under a given strain. Due to the separation of the nanowire and the change in current path geometry, the variation in strain resistance of the sensor can be primarily attributed to these factors. Therefore, precision in strain regulation can be adjusted by altering the angle θ (0°, 60°, or 90°) of the nanowire. At the same time, the stability of the AgNW/Pattern-PDMS (AgNW/Pat-PDMS) conductive film application was verified by preparing a sandwich structure PDMS/AgNW/Pat-PDMS stretchable strain sensor. The sensor exhibited high sensitivity within the operating sensing range (gauge factor (GF) of 15 within ~120% strain), superior durability (20,000 bending cycles and 5000 stretching cycles), and excellent response toward bending.
Quantitative Evaluation of Blending Behavior between Virgin Asphalt and Aged Asphalt Incorporating a New Bio-Based Warm-Mix Rejuvenator
Authors: Yu Le , You Shiyuan , He Zhaoyi , Wei Dingbang , Kong Lin
Published: August 2024

The blending degree between virgin asphalt and aged asphalt has a significant effect on road performance of reclaimed asphalt mixture. This study presented an innovative examination of blending behavior between virgin asphalt and aged asphalt incorporating a new bio-based warm-mix rejuvenator (BWR) by utilizing Atomic Force Microscopy (AFM). Through analyzing the variation of several micro-morphology parameters between virgin asphalt and aged asphalt (or recycled asphalt) after blending, an index of regenerative blending degree (RBD) was proposed to quantitatively evaluate their blending behavior, and the effect of various blending temperatures and durations on regenerative blending degree was investigated. The results show that the regenerative blending degree between virgin asphalt and aged asphalt was higher than that between virgin asphalt and recycled asphalt under the same blending condition. A clear linear correlation was observed between the regenerative blending degree calculated by 3D micro-morphology parameters and the dosage of bio-based warm-mix rejuvenator in recycled asphalt, with a correlation coefficient of 0.98. With the increase in blending duration, the regenerative blending degree between virgin asphalt and recycled asphalt increased first and then decreased, but continued to improve with the increase in blending temperature, which indicates that a higher blending temperature and prolonging the blending duration properly have a positive effect on the blending processing between virgin asphalt and recycled asphalt. Compared with the regenerative blending degree calculated by 2D micro-morphology parameters, the regenerative blending degree calculated by 3D micro-morphology parameters is more reasonable to quantify the blending behavior between virgin asphalt and recycled asphalt.
Dielectric Response of ZnO/PMMA Nanocomposites with Atmospheric Pressure Plasma-Modified Surfaces
Authors: Patsidis Anastasios C. , Dimitrakellis Panagiotis , Gogolides Evangelos , Psarras Georgios C.
Published: August 2024

In this work, the effect of etching the surface of polymer matrix nanocomposites with atmospheric pressure plasma targeting to achieve enhanced dielectric properties was investigated. Polymer nanocomposites, with varying reinforcing phase content, were modified by atmospheric-pressure plasma resulting in an increase in the surface filler’s concentration. Polymethyl methacrylate (PMMA) matrix nanocomposites reinforced with zinc oxide (ZnO) nanoparticles were prepared and dielectrically studied as a function of the nanoparticle content and the plasma modified surfaces. The electrical response of the composite systems was studied by means of Broadband Dielectric Spectroscopy (BDS) over a wide range of temperatures and frequencies. The dielectric permittivity increased with the embedded phase content and with plasma surface treatment. Energy density followed the same trend as dielectric permittivity, and the plasma-treated nanocomposite with the higher ZnO content exhibited approximately 27% higher energy density compared to the unreinforced matrix.
Ni50Mn37.5Sn12.5 Heusler Alloy: Influence of Co Addition on the Structure, Martensitic Transition, and Magnetic Properties
Authors: Bekhouche Ahlem , Alleg Safia , Dadda Karima , Costa Benilde F. O. , Wederni Asma , Suñol Joan-Josep
Published: August 2024

The impact of Co-addition (x = 0, 2, 4, and 6 at. %) in the as-cast and annealed Ni50Mn37.5Sn12.5 Heusler alloy at 900 °C for 24 h on the microstructure, magnetic properties, and the martensitic transition was studied using X-ray diffraction (XRD), scanning electron microscopy, vibrating sample magnetometry, and differential scanning calorimetry. The crystal structure of as-cast samples consists of a 14M modulated martensite structure, a face-centered (FCC) γ phase, and a face-centered tetragonal (FCT) MnNi-type phase L10. The as-cast samples show a dendritic microstructure with different contrasts and non-uniform distribution. The annealed samples exhibit dual 14M and γ phases for the Co0 and Co2, but 14M + γ + MnNi for the Co4 and Co6. The appearance of the martensitic transformation in the annealed Co0 and Co2 samples can be due to the disappearance of the dendritic microstructure. The characteristic temperatures (martensite start, Ms; martensite finish, Mf; austenite start, As; and austenite finish, Af) decrease with Co addition. A ferromagnetic-like order exists at a lower temperature of 1.8 K for the as-cast and annealed samples and decreases at 300 K. The annealing increases the fraction of the AFM contributions at 300 K. The exchange bias values of the Co0, An-Co2, and An-Co6 are 146.7 Oe, 24 O2, and 32.6 Oe, respectively, at 300 K.
Finite Element Method for a Fractional-Order Filtration Equation with a Transient Filtration Law
Authors: Alimbekova Nurlana , Berdyshev Abdumauvlen , Madiyarov Muratkan , Yergaliyev Yerlan
Published: August 2024

In this article, a numerical method is proposed and investigated for an initial boundary value problem governed by a fractional differential generalization of the nonlinear transient filtration law which describes fluid motion in a porous medium. This type of equation is widely used to describe complex filtration processes such as fluid movement in horizontal wells in fractured geological formations. To construct the numerical method, a high-order approximation formula for the fractional derivative in the sense of Caputo is applied, and a combination of the finite difference method with the finite element method is used. The article proves the uniqueness and continuous dependence of the solution on the input data in differential form, as well as the stability and convergence of the proposed numerical scheme. The linearization of nonlinear terms is carried out by the Newton method, which allows for achieving high accuracy in solving complex problems. The research results are confirmed by a series of numerical tests that demonstrate the applicability of the developed method in real engineering problems. The practical significance of the presented approach lies in its ability to accurately and effectively model filtration processes in shale formations, which allows engineers and geologists to make more informed decisions when designing and operating oil fields.
Intracoronary Imaging for Changing Therapeutic Decisions in Patients with Multivascular Coronary Artery Disease
Authors: Pasaroiu Dan , Benedek Imre , Popa Teodora , Tolescu Constantin , Chitu Monica , Benedek Theodora
Published: August 2024

Background and Objectives: Atherosclerotic disease is a major contributor to heart failure, stroke, and myocardial infarction, significantly lowering the quality of life and life expectancy and placing a significant burden on healthcare. Not all lesions deemed non-significant are benign, and conversely, not all significant lesions are causative of ischemia. Fractional flow reserve (FFR) provides a functional assessment of coronary lesions, while optical coherence tomography (OCT) offers detailed imaging of plaque morphology, aiding in therapeutic decision-making. The objective of this study was to evaluate the utility of OCT and FFR as adjunctive tools in the catheterization laboratory for guiding therapeutic decisions in patients with multivessel disease for non-culprit vessels. Specifically, we aimed to assess how OCT and FFR influence therapeutic decision-making in patients with multivessel coronary artery disease. Materials and Methods: A total of 36 patients with acute coronary syndrome (ACS) and multivessel disease were randomized 1:1 into two groups: one guided by FFR alone and the other by a combination of FFR and OCT. For the FFR group, revascularization decisions for non-culprit lesions were based solely on FFR measurements. If the FFR was >0.8, the procedure was concluded, and the patient received maximal medical treatment. If the FFR was ≤0.8, a stent was placed. For the FFR + OCT group, if the FFR was >0.8, the revascularization decision was based on OCT findings. If there were no vulnerable plaques (VP), the procedure was concluded, and the patient received maximal medical treatment. If OCT imaging indicated VP, then the patient underwent revascularization. If the FFR was ≤0.8, the patient underwent revascularization regardless of OCT findings. Results: OCT imaging altered the therapeutic decision in 11 cases where FFR measurements were above 0.8, but the lesions were characterized as VP. Analyzing the total change in the decision to stent, 4 cases in the FFR group and 15 cases in the FFR and OCT groups (4 based on FFR and 11 on OCT) revealed a statistically significant difference (p = 0.0006; Relative Risk = 0.2556; 95% CI: 0.1013 to 0.5603). When analyzing the change in the total decision both to stent and not to stent, we observed a statistically significant difference, with Group 1 having 7 cases and Group 2 having 15 cases (p = 0.0153; Relative Risk = 0.4050; 95% CI: 0.2004 to 0.7698. Conclusions: Based on the findings of this study, OCT significantly increases the percentage of stenting procedures by identifying vulnerable lesions. The use of intracoronary imaging facilitates the timely identification and treatment of these vulnerable lesions. This underscores the crucial role of OCT in enhancing the precision of coronary interventions by ensuring timely intervention for vulnerable lesions, thereby potentially improving patient outcomes.
Cardiac Angiosarcoma in the Right Atrium Treated by Surgical Resection
Authors: Dragicevic-Antonic Milica , Rankovic-Nicic Ljiljana , Stamenkovic Gordana , Petrovic Masa , Loncar Goran , Markovic Nikola , Dimitrijevic Ana , Bulatovic Sulin , Cirkovic Milan , Borzanovic Branislava , Antonic Zelimir , Pirnat Maja , Manka Robert , Bojic Milovan
Published: August 2024

We present the case of a 49-year-old female of Caucasian European descent with chest tightness, fatigue, and palpitations, ultimately diagnosed with primary intracardiac angiosarcoma. Initial echocardiography revealed a significant mass within the right atrium, infiltrating the free wall. Surgical intervention included tumor excision and partial resection of the superior vena cava. Histopathological examination confirmed a high-grade angiosarcoma. Postoperative imaging identified a recurrent mass in the right atrium, suggestive of thrombus, alongside Takotsubo cardiomyopathy. Considering the elevated surgical risks and the presence of cardiomyopathy, management included anticoagulation therapy with Warfarin and adjuvant chemotherapy with Paclitaxel. Follow-up cardiac magnetic resonance imaging demonstrated a recurrent angiosarcoma with superimposed thrombus. This case presents the complex diagnostic and therapeutic landscape of angiosarcoma, highlighting the critical importance of early surgical intervention, advanced imaging techniques, and vigilant postoperative monitoring.
Effect of Heat Treatment on Microstructures and Mechanical Properties of Graphene/Aluminum Composites: Insights from Atomic Simulations
Authors: Shen Zixuan , Chen Lei , Wang Liya , Xia Jun , Wang Ruijie , Tang Chun
Published: August 2024

Graphene nanoplatelets (GNPs) have significant potential as reinforcement agents in metallic materials. Understanding the interfacial structure between GNPs and an aluminum matrix (AlM) is crucial for this composite (GNPs/AlMC) design and application. Studies on the effects of heat treatment on the interfacial character and its influence on mechanical properties at the atomic scale are, therefore, of high importance. This study presents molecular dynamics simulations investigating the effects of heat treatment on the interfacial structural evolution between GNPs and AlM and how such behavior tunes mechanical performance. The results show that the number of interfacial bonds increases significantly when the heat treatment temperature reaches 900 K, below which it stays at low level. Compared with the heat treatment temperature, the pressure has less effect on the interfacial bonds of GNPs/AlMCs. Moreover, defective GNPs with pores at certain heat treatment temperatures promote the formation of Al-C bonds at the interface and improve the mechanical properties of GNPs/AlMCs. These findings underscore the potential for utilizing heat treatment and defect engineering to improve interfacial bonding and achieve improved mechanical performance in GNPs/AlMCs.
Effect of Corrosion Environment on Mechanical Behavior of 5083/6005A Welded Joints
Authors: Wu Hailiang , Chen Yuqiang , Lu Dingding , He Guanqiang
Published: August 2024

The corrosion fatigue behavior of welded joints is a critical concern in the transportation industry, which shortens their service life. In this paper, the corrosion damage of 5083/6005A welded joints exposed to different conditions (3.5% NaCl + 0.01 mol/L NaHSO3, 3.5% NaCl, 0.6 mol/L NaHSO3, and 3.5% NaCl + 0.01 mol/L NaHSO3-75 MPa) was investigated by using tensile and fatigue tests, polarization curves, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The findings indicate that elongation and fatigue life were most adversely affected by exposure to 3.5% NaCl + 0.01 mol/L NaHSO3-75 MPa. This was followed by the exposure to 3.5% NaCl + 0.01 mol/L NaHSO3, then 3.5% NaCl, with the mildest effects observed under 0.6 mol/L NaHSO3. The corrosion mechanisms were elucidated and the corrosion model was established through the analysis of corrosion morphologies and corrosion products. The corrosion fatigue fracture model was developed by analyzing the fracture surfaces. These findings provide references for preventing the corrosion-fatigue fractures of 5083/6005A welded joints, extending their service life, and enhancing the operational safety and reliability of trains.
Exploring the Impact of Pre-Mechanical Activation of Nickel Powder on the Structure of Deposited Metal: A Deep Neural Network Perspective
Authors: Malashin Ivan , Kobernik Nikolay , Pankratov Alexandr , Andriyanov Yuri , Aleksandrova Vitalina , Tynchenko Vadim , Nelyub Vladimir , Borodulin Aleksei , Gantimurov Andrei , Martysyuk Dmitry , Galinovsky Andrey
Published: August 2024

This study explores the potential application of the mechanical activation (MA) of nickel powder for incorporation into the composition of powder wire blends for the deposition of wear-resistant coatings. Nickel powder of PNE-1 grade was processed in a vibrational mill for various durations (4 to 16 min) with different combinations of grinding media. The influence of MA parameters on the bulk density and apparent particle size of nickel powder was investigated. The greatest effect was observed at the maximum processing time of 16 min, where electron microscopy revealed significant deformation and an increase in discoid particles, leading to enhanced energy accumulation. Nickel powder processed with a combination of 6 balls that are 20 mm in diameter and 8 balls that are 10 mm in diameter showed significant changes, though no major alteration in chemical composition was noted. XRMA indicated that the powder’s surface was partially covered with oxides, with a composition of 96.8–98.4% Ni and 0.8–1.7% O2. Additionally, the effect of nickel powders after the treatment on the structure of deposited metal was determined, demonstrating alterations in the morphology and a slight increase in hardness. Furthermore, a convolutional neural network (CNN)-based approach was proposed to discern fragments within images depicting surface microstructures, both with and without MA.
A Droplet-Based Microfluidic Platform for High-Throughput Culturing of Yeast Cells in Various Conditions
Authors: Yu Min-Chieh , Sun Yung-Shin
Published: August 2024

Yeast plays a significant role in a variety of fields. In particular, it is extensively used as a model organism in genetics and cellular biology studies, and is employed in the production of vaccines, pharmaceuticals, and biofuels. Traditional “bulk”-based studies on yeast growth often overlook cellular variability, emphasizing the need for single-cell analysis. Micro-droplets, tiny liquid droplets with high surface-area-to-volume ratios, offer a promising platform for investigating single or a small number of cells, allowing precise control and monitoring of individual cell behaviors. Microfluidic devices, which facilitate the generation of micro-droplets, are advantageous due to their reduced volume requirements and ability to mimic in vivo micro-environments. This study introduces a custom-designed microfluidic device to encapsulate yeasts in micro-droplets under various conditions in a parallel manner. The results reveal that optimal glucose concentrations promoted yeast growth while cycloheximide and Cu2+ ions inhibited it. This platform enhances yeast cultivation strategies and holds potential for high-throughput single-cell investigations in more complex organisms.
Study on the Performance of Deep Red to Near-Infrared pc-LEDs by the Simulation Method Considering the Distribution of Phosphor Particles
Authors: Li Chenghang , Fang Zikeng , Yan Ying , Li Henan , Luo Xiang , Wang Xuyue , Zhou Ping
Published: August 2024

Effectively utilizing deep red to near-infrared (DR-NIR) phosphors to achieve the optimal performance of NIR phosphor-converted white LEDs (DR-NIR pc-wLEDs) is currently a research hotspot. In this study, an optical model of DR-NIR pc-wLEDs with virtual multilayer fluorescent films was established based on the Monte Carlo ray-tracing method. Different gradient distributions of the particles were assigned within the fluorescent film to explore their impact on the optical performance of pc-LEDs. The results show that, for the case with single-type particles, distributing more DR-NIR particles far from the blue LED chip increased the overall radiant power. The distribution of more DR-NIR particles near the chip increased the conversion ratio from blue to DR-NIR light. The ratio of the 707 nm fluorescence emission intensity to the 450 nm excitation light intensity increased from 1:0.51 to 1:0.28. For multiple-type particles, changes in the gradient distribution resulted in dual-nature changes, leading to a deterioration in the color rendering index and an increase in the correlated color temperature, while also improving the DR-NIR band ratio. The reabsorption caused by the partial overlap between the excitation band of the DR-NIR particles and the emission band of the other particles enhanced the radiant power at 707 nm. Distributing DR-NIR phosphor particles closer to the chip effectively amplified this effect. The proposed model and its results provide a solution for the forward design of particle distributions in fluorescent films to improve the luminous performance of DR-NIR pc-wLEDs.