bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Wear and Surface Roughness Characteristics of Polylactic Acid (PLA)—Graphene 3D-Printed Composites by Box–Behnken Method
Authors: Avalappa Manjunath G. , Chate Vaibhav R. , Rangaswamy Nikhil , Avadhani Shriranganath P. , Chate Ganesh R. , Shettar Manjunath
Published: December 2024

The biodegradability and comparatively less harmful degradation of polylectic acid (PLA) make it an appealing material in many applications. The composite material is used as a feed for a 3D printer, consisting of PLA as a matrix and graphene (3 wt.%) as reinforcement. The composite is extruded in the form of wires using a screw-type extruder machine. Thus, prepared wire is used to 3D print the specimens using fused deposition modeling (FDM) type additive manufacturing technology. The specimens are prepared by varying the different process parameters of the FDM machine. This study’s primary objective is to understand the tribological phenomena and surface roughness of PLA reinforced with graphene. Initially, pilot experiments are conducted to screen essential factors of the FDM machine and decide the levels that affect the response variables, such as surface roughness and wear. The three factors, viz., layer height, printing temperature, and printing speed, are considered. Further experiments and analysis are conducted using the Box–Beheken method to study the tribological behavior of 3D-printed composites and the effect of these parameters on surface roughness and wear loss. It is interesting to note that layer height is significant for surface roughness and wear loss. The optimum setting for minimum surface roughness is layer height at 0.16 mm, printing temperature at 180 °C, and printing speed at 60 mm/s. The optimum setting for minimum wear loss is layer height at 0.24 mm, printing temperature at 220 °C, and printing speed at 90 mm/s. The desirability function approach is used to optimize (multiobjective optimization) both surface roughness and wear loss. The layer height of 0.16 mm, printing temperature of 208 °C, and printing speed of 90 mm/s are the optimum levels for a lower surface roughness and wear loss. The SEM images reveal various wear mechanisms, viz., abrasive grooves, micro-fractures, and the presence of wear debris. The work carried out helps to make automobile door panels since they undergo wear due to excessive friction, aging, material degradation, and temperature fluctuations. These are taken care of by graphene addition in PLA with an optimized printing process, and a good surface finish helps with proper assembly.
Benchmarking of Multispectral Pansharpening: Reproducibility, Assessment, and Meta-Analysis
Authors: Alparone Luciano , Garzelli Andrea
Published: December 2024

The term pansharpening denotes the process by which the geometric resolution of a multiband image is increased by means of a co-registered broadband panchromatic observation of the same scene having greater spatial resolution. Over time, the benchmarking of pansharpening methods has revealed itself to be more challenging than the development of new methods. Their recent proliferation in the literature is mostly due to the lack of a standardized assessment. In this paper, we draw guidelines for correct and fair comparative evaluation of pansharpening methods, focusing on the reproducibility of results and resorting to concepts of meta-analysis. As a major outcome of this study, an improved version of the additive wavelet luminance proportional (AWLP) pansharpening algorithm offers all of the favorable characteristics of an ideal benchmark, namely, performance, speed, absence of adjustable running parameters, reproducibility of results with varying datasets and landscapes, and automatic correction of the path radiance term introduced by the atmosphere. The proposed benchmarking protocol employs the haze-corrected AWLP-H and exploits meta-analysis for cross-comparisons among different experiments. After assessment on five different datasets, it was found to provide reliable and consistent results in ranking different fusion methods.
Investigation into the Prediction of Ship Heave Motion in Complex Sea Conditions Utilizing Hybrid Neural Networks
Authors: Liu Yuchen , Cheng Xide , Han Kunyu , Liu Zhechun , Feng Baiwei
Published: December 2024

While navigating at sea, ships are influenced by various factors, including wind, waves, and currents, which can result in heave motion that significantly impacts operations and potentially leads to accidents. Accurate forecasting of ship heaving is essential to guarantee the safety of maritime navigation. Consequently, this paper proposes a hybrid neural network method that combines Convolutional Neural Networks (CNNs), Bidirectional Long Short-Term Memory Networks (BiLSTMs), and an Attention Mechanism to predict the heaving motion of ships in moderate to complex sea conditions. The data feature extraction ability of CNNs, the temporal analysis capabilities of BiLSTMs, and the dynamic adjustment function of Attention on feature weights were comprehensively utilized to predict a ship’s heave motion. Simulations of a standard container ship’s motion time series under complex sea state conditions were carried out. The model training and validation results indicate that, under sea conditions 4, 5, and 6, the CNN-BiLSTM-Attention method demonstrated significant improvements in MAPE, APE, and RMSE when compared to the traditional LSTM, Attention, and LSTM-Attention methods. The CNN-BiLSTM-Attention method could enhance the accuracy of the prediction. Heave displacement, pitch displacement, pitch velocity, pitch acceleration, and incoming wave height were chosen as key input features. Sensitivity analysis was conducted to optimize the prediction performance of the CNN-BiLSTM-Attention hybrid neural network method, resulting in a significant improvement in MAPE and enhancing the accuracy of ship motion prediction. The research presented in this paper establishes a foundation for future studies on ship motion prediction.
Role of the Anaphase-Promoting Complex Activator Cdh1 in the Virulence of Cryptococcus neoformans
Authors: Liao Qiu-Hong , Han Lian-Tao , Guo Meng-Ru , Fan Cheng-Li , Liu Tong-Bao
Published: December 2024

Cryptococcus neoformans is a globally distributed human fungal pathogen that can cause cryptococcal meningitis with high morbidity and mortality. In this study, we identified an anaphase-promoting complex (APC) activator, Cdh1, and examined its impact on the virulence of C. neoformans. Our subcellular localization analysis revealed that Cdh1 is situated in the nucleus of C. neoformans. Disrupting or overexpressing the CDH1 gene caused abnormal capsule formation in C. neoformans. The cdh1Δ mutant displayed slight sensitivity when grown at 37 °C, indicating that Cdh1 plays a role in maintaining the growth of C. neoformans at 37 °C. A fungal virulence assay showed that Cdh1 is closely associated with the virulence of C. neoformans, and both the cdh1Δ mutant and CDH1OE overexpression strains significantly diminished the virulence of C. neoformans. The Cryptococcus–macrophage interaction assay revealed that both the cdh1∆ mutant and the CDH1OE strains had significantly lower proliferation ability inside macrophages. Furthermore, the infection of the cdh1Δ mutant significantly activated neutrophil recruitment, as well as Th2 and Th17 immune responses, in lung tissue. In summary, our findings indicate that Cdh1 is crucial for producing virulence factors and fungal virulence in C. neoformans. The findings of this study can offer valuable insights and form the basis for further study of the regulatory mechanisms governing the pathogenicity of C. neoformans, potentially leading to the development of novel therapeutic strategies.
Comparative Analysis of Freeze-Dried Pleurotus ostreatus Mushroom Powders on Probiotic and Harmful Bacteria and Its Bioactive Compounds
Authors: Törős Gréta , Béni Áron , Peles Ferenc , Gulyás Gabriella , Prokisch József
Published: December 2024

Pleurotus ostreatus (oyster mushroom) holds excellent promise worldwide, bringing several opportunities and augmenting the tool sets used in the biotechnology field, the food industry, and medicine. Our study explores the antimicrobial and probiotic growth stimulation benefits of freeze-dried P. ostreatus powders (OMP-TF, oyster mushroom powder from the total fresh sample; OMP-CSR, oyster mushroom powder from the cooked solid residue; OMP-CL, oyster mushroom powder from the cooked liquid), focusing on their bioactive compounds and associated activities. Our research examined polysaccharide fractions—specifically total glucans and α- and β-glucans—alongside secondary metabolites, including polyphenols and flavonoids, from freeze-dried mushroom powders. Additionally, carbon nanodots (CNDs) were also characterized. The growth inhibition was tested against Escherichia coli and Staphylococcus epidermidis, while the capacity for stimulating probiotic growth was evaluated using Lactobacillus plantarum and Lactobacillus casei. Evidence indicates that OMP-CL and OMP-CSR exhibit significant antimicrobial properties against S. epidermidis Gram-positive bacteria. OMP-CL notably promoted the growth of L. casei. OMP-CL, containing the most significant number of CNDs, has shown to be a valuable source for gut microbiota modulation, with its antimicrobial and probiotic-stimulating efficacy. However, further in vitro and in vivo studies should be performed to explore CNDs and their behavior in different biological systems.
Assessment of the Chemical Diversity and Functional Properties of Secondary Metabolites from the Marine Fungus Asteromyces cruciatus
Authors: González-Troncoso María Paz , Landeta-Salgado Catalina , Munizaga Javiera , Hornedo-Ortega Ruth , García-Parrilla María del Carmen , Lienqueo María Elena
Published: December 2024

Natural compounds derived from microorganisms, especially those with antioxidant and anticancer properties, are gaining attention for their potential applications in biomedical, cosmetic, and food industries. Marine fungi, such as Asteromyces cruciatus, are particularly promising due to their ability to produce bioactive metabolites through the degradation of marine algal polysaccharides. This study investigates the metabolic diversity of A. cruciatus grown on different carbon sources: glucose, Durvillaea spp., and Macrocystis pyrifera. Crude extracts of fungal biomass were analyzed for total phenolic content (TPC), antioxidant capacity (TAC), toxicity, and phenolic compound identification using ultra-high-performance liquid chromatography coupled with high-resolution electrospray ionization mass spectrometry (UHPLC-MS/MS). The analysis revealed the presence of anthraquinone compounds, including emodin (0.36 ± 0.08 mg/g DW biomass) and citrereosein in glucose medium and citrereosein and endocrocin in M. pyrifera medium. No such compounds were detected in Durvillaea spp. medium. The glucose-grown extract exhibited the highest TPC (3.09 ± 0.04 mg GAE/g DW) and TAC (39.70 ± 1.0 µmol TEq/g biomass). Additionally, no detrimental effects were observed on a neuronal cell line. These findings highlight the influence of carbon sources on the production of bioactive metabolites and their functional properties, providing valuable insights into the biotechnological potential of A. cruciatus.
Dyslipidemia and Development of Chronic Kidney Disease in Non-Diabetic Japanese Adults: A 26-Year, Community-Based, Longitudinal Study
Authors: Okawa Yukari , Mitsuhashi Toshiharu
Published: December 2024

Follow-up studies evaluating the relationship between dyslipidemia and chronic kidney disease (CKD) in non-diabetic populations are limited. This longitudinal study (1998–2024) examined whether the prevalence of dyslipidemia is associated with the subsequent development of CKD in non-diabetic Japanese adult citizens of Zentsuji, Kagawa Prefecture, Japan. Dyslipidemia was defined as low-density lipoprotein cholesterol concentrations ≥ 140 mg/dL, high-density lipoprotein cholesterol concentrations < 40 mg/dL, and/or triglyceride concentrations ≥ 150 mg/dL. Participants were considered to have developed CKD if their estimated glomerular filtration rate was <60 mL/min/1.73 m2. The proportional hazards assumption was violated. Therefore, the Weibull accelerated failure-time model was selected using the Akaike and Bayesian information criteria. The final cohort included 5970 participants, 41.6% of whom were men. The mean follow-up was 7.09 years. After the follow-up, 1890 (31.7%) participants developed CKD. Participants with dyslipidemia had a 5% shorter survival time (95% confidence interval: 3–7%) to incident CKD compared with those without dyslipidemia in the full model. High-density lipoprotein cholesterol concentrations < 40 mg/dL and triglyceride concentrations ≥ 150 mg/dL also reduced the survival time to CKD onset by 5–6%. Our results indicate that controlling the lipid profile to an appropriate range may contribute to reducing the risk of future onset of CKD.
From Biosafety to National Security: The Evolution and Challenges of Biosafety Laboratories
Authors: Gao Wanying , Wu Zongzhen , Zuo Kunlan , Xiang Qiangyu , Zhang Lu , Chen Xiaoya , Tan Feng , Liu Huan
Published: December 2024

From the perspective of science and technology history, we review the development history and key events of global biosafety laboratories to deepen our understanding of biosafety. The construction history of biosafety laboratories reveals the complex interactions between science, social needs, public health safety, and national security. From the recognition of laboratory infection incidents in the late 19th century to the potential hazards of biological warfare and the development of biotechnology in the mid-20th century, the gradual establishment of a laboratory biosafety level system to the construction of high-level biosafety laboratories in the 21st century to respond to global infectious disease challenges, each stage of development is closely related to the social background, technological progress, public health needs and national security considerations of the times.
Airborne LiDAR Applications at the Medieval Site of Castel Fenuculus in the Lower Valley of the Calore River (Benevento, Southern Italy)
Authors: Corbo Antonio
Published: December 2024

This paper explores the application of Airborne Laser Scanning (ALS) technology in the investigation of the medieval Norman site of Castel Fenuculus, in the lower Calore Valley, Southern Italy. This research aims to assess the actual potential of the ALS dataset provided by the Italian Ministry of the Environment (MATTM) for the detection and visibility of archaeological features in a difficult environment characterised by dense vegetation and morphologically complex terrain. The study focuses on improving the detection and interpretation of archaeological features through a systematic approach that includes the acquisition of ALS point clouds, the implementation of classification algorithms, and the removal of vegetation layers to reveal the underlying terrain and ruined structures. Furthermore, the aim was to test different classification and filtering techniques to identify the best one to use in complex contexts, with the intention of providing a comprehensive and replicable methodological framework. Finally, the Digital Elevation Model (DTM), and various LiDAR-derived models (LDMs), were generated to visualise and highlight topographical features potentially related to archaeological remains. The results obtained demonstrate the significant potential of LiDAR in identifying and documenting archaeological features in densely vegetated and wooded landscapes.
Making Hidden Sustainable Urban Planning and Landscape Knowledge Visual and Multisensorial
Authors: Balsas Carlos J. L.
Published: December 2024

Many cityscapes and landscapes create reactions of awe due to their unexpected characteristics or uniqueness. First glance observations may not reveal or enable the understanding of all natural, social, economic, environmental, and cultural processes taking place at a given moment or, particularly, how those places have evolved and been transformed into being what they are today. Research helps to uncover hidden layers of reality and make sense of relationships among elements, dimensions, and processes. Distinct research styles of variable intensity and comprehensiveness are required to respond to the needs of multiple stakeholders. Quantitative research methods have become increasingly sophisticated, and while they serve to enhance one’s knowledge of complex phenomena, they can also be difficult to understand. To what extent can urban planners and landscape architects utilize visual and multisensorial literacies to bring about more transparency and significance to territorial transformation processes? This paper analyzes how four educational and research programs implemented at the University at Albany built upon visual and multisensorial research methods to augment educational outcomes, bolster scholarly significance, and provide up-to-date knowledge to empower concerned stakeholders to help change unsustainable urbanization practices, social inequities and injustices in cities, car dependence and sedentary lifestyles, protect natural resources and livelihoods, while reducing environmental and social harm. The methods comprised literature reviews, self-reflections on the implemented programs, and analyses of participant evaluations of various outreach activities. The paper concludes with remarks for other researchers interested in making their pedagogical and scholarly activities more effective and rewarding for themselves and their intended beneficiaries.
Spatial Dynamics of Specialized and Sophisticated Small and Medium-Sized Enterprises on New High-Quality Productive Forces from an Evolutionary Economic Geography Perspective
Authors: Zhong Huibo , Chu Mingwei , Xia Yuhang , Zhai Keyu , Gao Xing
Published: December 2024

Amidst global economic stagnation, China is undergoing a significant economic transformation by fostering new high-quality productive forces (NHPFs). In this transformative context, specialized and sophisticated small and medium-sized enterprises (SpecSof SMEs) play a critical role. This paper develops a framework from an evolutionary economic geography (EEG) perspective to analyze how these SMEs influence NHPFs. The study assesses the impact of specialized and sophisticated SMEs on NHPFs using OLS and addresses potential endogeneity issues through the application of instrumental variables. The results show that the Specialized and Sophistication Index (SSI) positively impacts NHPFs, with its effect strengthening from the company to the municipal level (by about 25%) but weakening at the provincial and national levels (to half of the municipal level), highlighting a clear marginal effect on regional NHPFs. Additionally, the geographically weighted regression (GWR) model was employed to investigate the complex and spatially varied relationships between key characteristics of specialized and sophisticated SMEs and NHPFs. Our findings suggest that while the relationship between SSI and NHPFs is generally positive, it is spatially heterogeneous, arising from variations in regional economic structures, market maturity, and industrial characteristics. This study provides a theoretical framework for understanding regional disparities in NHPF development through SpecSof SMEs and offers empirical evidence to inform region-specific policies and spatial planning strategies.
Linking Plant Diversity and Urban Uses at the City-Block Scale to Inform Urban Planning
Authors: Deparis Muriel , Legay Nicolas , Castellanos Arthur , Duque Chloé , Guilloteau Ulysse , Isselin-Nondedeu Francis , Bonthoux Sébastien
Published: December 2024

A challenge for urban ecology is to reduce biotic homogenisation by promoting plant diversity from local to city scales. As ecological and social components constantly interact in cities, an urban landscape characterisation reflecting socio-spatial functioning seems essential. However, spatially explicit description of cities at a relevant scale for urban planning are uncommon in ecological studies. Here, we explored a new approach based on the city-block scale, common in urban geography and planning, to directly link urban uses and patterns of herbaceous plant communities. We characterised all city blocks of a medium-sized French city (Blois). We inventoried grassland and meadows in 129 city blocks (10% of the whole city) for seven public and private urban uses (collective housing, individual housing, industrial, public service, park, land reserve, and road verge). We measured alpha diversity, community composition, regional originality of urban uses, and beta diversity between them. Urban land reserved for future development and parks harbour unique community composition within the city. Collective and individual housings have the same average alpha diversity, but the variability in community composition was higher for individual housing blocks. School and industrial city blocks have important alpha diversity and regional originality. Road verges have the highest alpha diversity but low regional originality and many common urban and regional species. Large green spaces with original communities should be protected during urban densification. The verticalization of residential housing could be an efficient means of internal urban densification if the lowest level of management intensity is promoted to maintain diversified vegetation. Some little-studied uses (schools, industrial city blocks) present opportunities to impede urban homogenisation.
Liver Stiffness, Not Steatosis, Predicts Mortality in MASLD Patients: An NHANES Analysis
Authors: Huang Yuting , Wang Yichen , Yan Yan , Antwi Samuel O. , Badurdeen Dilhana S. , Yang Liu
Published: December 2024

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) has surged as a major cause of liver transplants in the United States. Existing studies have presented conflicting findings regarding the association between liver characteristics (specifically steatosis and fibrosis) and mortality. This study investigates the relationship between the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) via vibration-controlled transient elastography (VCTE) and all-cause mortality in MASLD patients. Methods: Using the NHANES 2017-2018 database, 3821 individuals representing the United States population with MASLD underwent VCTE for liver stiffness measurement. Exclusion criteria were applied, eliminating ineligible cases, incomplete examinations, underage individuals, and those with hepatitis B or C, along with significant alcohol consumption history. Cox proportional hazard models assessed the hazard ratio (HR) for all-cause mortality in CAP and LSM. Cox regression analysis with interaction terms was employed for deeper exploration. Results: The study unveiled a strong, independent correlation between LSM and all-cause mortality. However, the CAP failed to demonstrate a significant association with mortality in both univariate and adjusted analyses, contrary to recent findings. The analysis underscores the importance of accurately measuring liver stiffness via VCTE in predicting adverse outcomes in MASLD patients, emphasizing the pivotal role of fibrosis in assessing mortality risk. Conclusion: This study reaffirms the robust link between liver fibrosis (measured through VCTE) and mortality among MASLD individuals. The absence of a significant association between steatosis (indicated by CAP) and mortality challenges recent research, urging further comprehensive investigations with larger cohorts to delineate steatosis’ precise impact on MASLD-related mortality.
Recent Studies on Nanomaterials as Additives to Lubricants Under Electrified Conditions for Tribology: Review
Authors: Nasser Khodor , Guimarey María J. G. , Pereira Neuma das Mercês
Published: December 2024

The tribological performance of nanolubricants in electric drivetrains has gained attention due to the rapid growth of electric vehicles. Nanomaterials, especially those with high thermal conductivity and low electrical conductivity, are favored as lubricant additives for use in electrical conditions. Low-viscosity lubricants, known for their good thermal conductivity, are increasingly being considered for electric powertrains. Combining appropriate nanomaterials with lubricants can optimize nanolubricants for electric drivetrains, with stability, tribocorrosion, and electro-viscosity being key factors. Traditional tribometers, when modified to apply external electrical power, allow testing of nanolubricants under electrical conditions, providing insights into their behavior with positive and/or negative electrical charges. To achieve accurate and stable results, tribological test systems must be adapted, requiring well-isolated rigs for controlled data collection. This adaptation enables a better understanding of the interaction between nanomaterials and surfaces under lubrication. This paper reviews studies that use modified tribometers to analyze nanolubricant performance under mechanical and electrical conditions and explores the effects of electrical and thermal factors on lubricant properties, nanomaterials, and their mechanisms under triboelectric conditions.
From Dienophiles to Dienes: Catalysis by Polystyrene-Supported Triphenylphosphine with Pentane-2,4-dione as Co-Catalyst
Authors: Espeland Ludvik O. , Sydnes Leiv K.
Published: December 2024

Three 1,1-diethoxyalk-3-yn-2-ones underwent isomerization and gave only the corresponding (3E,5E)-alkadienones in 72–87% yield when subjected to polystyrene-supported triphenylphosphine at 60 °C using acetylacetone as a co-catalyst. As a first step to make the dienes electron richer, the diethoxyacetyl moiety was reduced with sodium borohydride under Luche conditions and afforded the corresponding alcohols, with a 92% yield in the best case.
Corrosion Resistance Analysis in Nickel Coatings by Electrodeposition with Different Layers and Waveform Combinations
Authors: Yan Liang , Zhang Tao , Zhang Huajin , Liu Huan
Published: December 2024

Nickel (Ni) single-layer coatings were electrodeposited under varying pulse periods (T), duty cycles (θ), and average current densities (iav) using four distinct pulse current waveforms: rectangular (Rec), triangular (Tri), ramp-up triangular (Rup), and ramp-down triangular (Rdn). This study demonstrated, through dynamic polarization curves and surface morphology analysis, that single-layer coatings showed relatively good corrosion resistance when deposited at shorter pulse periods, larger duty cycles, and higher average current densities. Moreover, compared with other pulse current waveforms, single-layer coatings electrodeposited at T = 10 ms, θ = 0.5, and iav = 10 mA/cm2, 20 mA/cm2, and 40 mA/cm2 with Rdn had similar dynamic polarization curves and relatively good corrosion resistance. Consequently, two pulse current combinations, the descending gradient and convex gradient, were introduced for electrodepositing Ni multilayer coatings. Analysis revealed that the corrosion resistance of coatings deposited with the convex gradient current was further enhanced.
Research on Quantitative Characterization Model of Compressive Strength or Elastic Modulus of Recycled Concrete Based on Pore Grading
Authors: Xu Fuwei , Pan Hongke
Published: December 2024

The influence of different pore sizes on the compressive strength and elastic modulus of recycled concrete is an important issue in the academic circle. Aiming at this problem, a quantitative characterization model of the compressive strength and elastic modulus of recycled concrete based on pore grading was established in this paper. The compressive strength, elastic modulus, porosity and distribution of pore size of recycled concrete were measured by a concrete test and nuclear magnetic resonance technology, and the influences of different pore sizes on the compressive strength and elastic modulus of recycled concrete were analyzed, and the rationality of the quantitative characterization model was verified. The results showed that the compressive strength and elastic modulus of recycled concrete decreased with the increase in the recycled coarse aggregate replacement rate, and the decrease was more obvious with the increase in the substitution rate. The peak pore diameter in the distribution curve of porosity and pore diameter of recycled concrete increased, and the proportion of pore diameter above 50~200 nm and 200 nm also increased. The pore sizes, including those below 20 nm and 20~50 nm, had a positive correlation with the compressive strength and elastic modulus of recycled concrete, while the pore sizes, including those above 50~200 nm and 200 nm, had a negative correlation with the compressive strength and elastic modulus of recycled concrete. The test results of recycled concrete verify that the quantitative characterization model could better characterize the compressive strength and elastic modulus of recycled concrete.
Design of Self-Compacting Concrete with Reduced Cement Content by Aggregate Packing Method
Authors: Rudnicki Tomasz
Published: December 2024

This article presents the procedure for designing self-compacting cement concrete characterized by minimal free space and a maximally compacted mineral skeleton. Such a designed mix allows for lower cement consumption and an increased amount of mineral additives. The paper presents a broad analysis of the influence of different aggregate proportions (36 recipes) and verification of the properties of the concrete mix using CEM I 42.5 R cements and fly ash. As a result of the appropriately compacted mineral skeleton, only 17% free space was obtained, which will allow the amount of cement to be reduced from 500 kg/m3 to 350 kg/m3 while fully maintaining the properties of the mix and hardened concrete. After 90 days of curing, SCC concrete was characterized by a compressive strength above 68 MPa and a small 2.1% decrease in compressive strength after 100 freeze–thaw cycles.
Cost-Effective Laser Powder Bed Fusion of Ti-6Al-4V Grade 5: The Effect of Expanding Powder Size Distribution on Mechanical Performance
Authors: Kim Min , Kim Ohseop , Song Youngwon , Ko Chanyoung , Kim Jonggun , Habibnejad-korayem Mahdi , Kim Jeong
Published: December 2024

This study aims to assess the feasibility of expanding the powder size distribution (PSD) of Ti-6Al-4V grade 5 powder for LPBF to achieve cost reduction. Parameter optimization to minimize the degradation of mechanical properties due to the expanded particle size distribution was conducted. Mechanical tests for specimens built using optimized parameters revealed minor reductions in strength: 3.9% in tensile yield strength, 1.1% in compressive strength, 5.5% in shear strength, and 4.5% in bearing yield strength—all of which complied with MMPDS standards. Statistical analysis, using the Anderson–Darling test, demonstrated stable mechanical performance and minimal variation between the original and expanded PSDs. These results highlight the potential of an expanded PSD to achieve cost reductions while maintaining compliance with industry standards, offering a practical solution for LPBF applications in cost-sensitive and high-performance industries.
The Effect of the Chamber-Filling Ratio in Vibratory Shot Peening on Selected Surface Layer Properties of 30HGSA
Authors: Skoczylas Agnieszka , Zaleski Kazimierz
Published: December 2024

This study investigated the influence of the filling ratio of the working chamber and ball diameter in vibratory shot peening (VSP) on select properties of the surface layer. The tested material was 30HGSA steel, which is effectively used in the aviation industry. The following were analyzed: the surface roughness parameters, the shape of the Abbott–Firestone curve, the bearing area ratio Smr(c=50%), the microhardness distribution, the microhardness on the surface, and the residual stress σ on the surface. A change in the ratio of peaks and valleys in the maximum height of the profile was observed. After VSP, the valleys were dominant over the peaks. The most favorable values of the analyzed roughness parameters (Sz, Sp, and Sv) were obtained for d = 9.4 mm and kd = 33%. The bearing area ratio Smr(c=50%) was approximately 50 times higher than before VSP (the most favorable for d = 9.4 mm and kd = 33%). The largest thickness of the strengthened layer of 200 μm and the greatest increase in the microhardness equal to ΔHV 0.05 = 109 were obtained after VSP was conducted using the ball diameter d = 14.3 mm kd = 33%. Regardless of the VSP conditions, the absolute value of compressive stresses increased; the highest σ stresses were obtained for d = 3.0 mm and kd = 33%, and they were 88% higher than before the treatment. It was concluded that the recommended chamber-filling ratio for beneficial properties is kd = 33%.
Discussion on the Gradation and Interface Effects on the Dynamic Mechanical Behaviors of Hydraulic Concrete Based on Meso-Mechanical Simulation
Authors: Wang Chao , Zhou Xinyu , Deng Zhaopeng , Wang Xiaohua , Zhang Sherong , Wang Gaohui , Wei Peiyong
Published: December 2024

Hydraulic concrete is quite different from normal concrete in the terms of aggregate gradation and construction-induced interfaces. To explore their influences on the dynamic mechanical behaviors of hydraulic concrete, several mesoscale numerical models with different aggregate gradations and interfaces were established and subjected to dynamic compressive or tensile loadings. The results show that aggregate gradation significantly affected hydraulic concrete failure patterns under dynamic loads, but interface effects were less obvious, and stressing uniformity improved with an increasing loading rate. The dynamic compressive and tensile strengths of hydraulic concrete showed a strain rate effect independent of gradation, but decreased with larger coarse aggregates, especially at higher rates. Weak-bonding interfaces significantly reduced strength at low loading rates, with a more pronounced effect on tensile strength than compressive strength. The results of this study provide a theoretical basis for the application of hydraulic concrete containing large-size aggregates in practical engineering.
Tribological Properties of Selected Ionic Liquids in Lubricated Friction Nodes
Authors: Madej Monika , Kowalczyk Joanna , Kowalski Marcin , Grabowski Paweł , Wernik Jacek
Published: December 2024

This article compares the rheological and tribological properties of three ionic liquids: Tributyl(methyl)phosphonium dimethyl phosphate 97%—MFCD, 1-Butyl-3-methylimidazolium hexafluorophosphate 97%—BMIMPF6, and 1-Butyl-3-methylimidazolium tetrafluoroborate 98%—BMIMBF4. Their density and kinematic viscosity at 20 °C and 40 °C were investigated, and tribological tests were carried out at the same temperatures with ball-on-disc contact. The test materials were made of 100Cr6 steel. A scanning electron microscope was used to image the wear tracks, while an EDS analyzer was employed to determine the chemical composition at the points of wear on the samples. A confocal microscope was used to analyze the geometric structure of the samples before and after the tribological tests. The results of the tests indicated that an increase in temperature reduced the dynamic viscosity of all the ionic liquids tested. At the same time, an increase in the MFCD and BMIMBF4 ionic liquid density and a decrease in the density of the BMIMPF6 ionic liquid were observed. The BMIMPF6 ionic liquid used for this study provided the lowest value of linear wear at both temperatures, ambient and 40 °C. However, for the BMIMBF4 ionic liquid, significant wear was observed for the tested discs and balls, with corrosive pitting on their surfaces.
Development of Digital Flow Valve Applied to Aero-Engine Fuel Control and Research on Performance of Its Flow Characteristics
Authors: Li Yuesong
Published: December 2024

Digital valves have strong anti-pollution ability and good linearity, so they are more suitable for aero-engine fuel control. However, for high-precision flow control, incremental digital valves require a high-precision, high-dynamic servomotor drive; binary-coded digital valves require many on/off valves; and high-speed switching digital valves can cause flow shock and pulsation. In this study, an aero-engine fuel control decimal-coded digital flow valve was developed, which not only has the advantages of digital valves but also avoids the above problems. Firstly, the structure and operation principle of the decimal-coded digital flow valve is introduced; then, its model is established based on Simulink/Simcape, and its flow characteristics are simulated and analyzed. Then, experiments on the flow characteristics are presented. The simulation and experiment show that under a supply pressure of 1 MPa, 2 MPa, and 3 MPa, the maximum flow of the decimal-coded digital valve is 11.4457 L/min, 16.3719 L/min, and 19.3733 L/min, and the control accuracy is 0.0775 L/min, 0.1086 L/min, and 0.1294 L/min, respectively. In addition, it has very good linearity, and the settling time is less than 0.09s.
Research on the Strain and Stress of Powered Roof Support Construction to Limit Damage
Authors: Szurgacz Dawid
Published: December 2024

A powered roof support in a mining complex comprises a set of sections positioned side by side. Thus, it creates space for the mining longwall shearer and the excavated material haulage conveyor. The main role of the powered roof support is to secure the machinery and equipment, as well as the working crew. This roof support also takes over the load from the rock mass during operation. The loads and phenomena that cause damage to the powered roof support construction in real conditions became the basis for conducting a series of studies and analyses of the stresses and strains that occur. This study aimed to obtain the results of research and analysis on the damage to the floor base, which is the most important part of the entire powered roof support construction. The actual pressure measurements carried out in the space under the piston leg of the powered roof support under real conditions indicated an excessive load on the powered roof support construction. This load was mainly due to the ceiling conditions, while the floor conditions for providing the construction were difficult to determine due to the too-soft floor substrate. The Finite Element Method (FEM) was used to solve the problem. The construction of the two powered roof support bases was subjected to numerical analysis in order to propose structural changes. The obtained numerical test results indicated a solution to the problem of damage and significant structural changes.
Machinery Regulation and Remanufacturing: A Link Between Machinery Safety and Sustainability
Authors: Beneduce Stefano , Vita Leonardo , Cantone Luciano , Caputo Francesco
Published: December 2024

On 14 June 2023, the European Parliament adopted Regulation (EU) 2023/1230 on machinery, which entered into force on 19 July 2023 (with some exceptions as per art. 54, according to a corrigendum issued to address a clerical error as regards the application dates in the original version) and shall apply from 20 January 2027, replacing the Machinery Directive 2006/42/EC. The main innovations/differences introduced by the Machinery Regulation (MR) compared to the Machinery Directive (MD) are critically analysed here, with a focus on sustainability issues. Some of these issues are covered by several international standards (such as BS 8887, ISO 10987 or DIN 91472), which also define the criteria and requirements for the remanufacturing process, although some technical gaps remain. Using the example of agricultural machinery, this paper proposes a methodology for determining the areas of acceptability for remanufactured products: these are expressed in terms of structural performance (e.g., the number of cycles ahead to failure expressed as the mutual of damage 1−D=0.625) and the functional and safety requirements of the original machine. In this way, the issue of “substantial modification of machinery” is explored in terms of the safety obligations that the remanufactured machinery must fulfil. The paper is therefore a contribution to circular design by providing general criteria for the extension of the service life of machinery while at the same time considering safety issues.
Electrical and Thermal Anisotropy in Additively Manufactured AlSi10Mg and Fe-Si Samples
Authors: Sarap Martin , Tiismus Hans , Kallaste Ants , Saarna Mart , Kolnes Märt , Shams Ghahfarokhi Payam , Vaimann Toomas
Published: December 2024

In the context of rising power densities in electrical machines, additive manufacturing presents an opportunity to develop more powerful thermal solutions. However, the physical properties of objects manufactured using this process remain unclear. This research examines the directional thermal and electrical conductivities of aluminum alloy (AlSi10Mg) and silicon steel (Fe-3.7%wt. Si) samples produced via laser powder bed fusion (LPBF), both prior to and following heat treatment. The findings indicate that the as-built aluminum samples exhibit higher conductivities in the orientation parallel to the LPBF build direction, while annealing results in higher conductivities overall and an absence of anisotropy. On the other hand, the silicon steel samples show constant conductivities and lack of anisotropy both before and after heat treatment. These results have practical applications in the design of additively manufactured electrical machines, where the thermal and electrical resistance of the materials have a major impact on thermal and electromagnetic performance.
A Dynamic Scheduling Method Combining Iterative Optimization and Deep Reinforcement Learning to Solve Sudden Disturbance Events in a Flexible Manufacturing Process
Authors: Yan Jun , Zhao Tianzuo , Zhang Tao , Chu Hongyan , Yang Congbin , Zhang Yueze
Published: December 2024

Unpredictable sudden disturbances such as machine failure, processing time lag, and order changes increase the deviation between actual production and the planned schedule, seriously affecting production efficiency. This phenomenon is particularly severe in flexible manufacturing. In this paper, a dynamic scheduling method combining iterative optimization and deep reinforcement learning (DRL) is proposed to address the impact of uncertain disturbances. A real-time DRL production environment model is established for the flexible job scheduling problem. Based on the DRL model, an agent training strategy and an autonomous decision-making method are proposed. An event-driven and period-driven hybrid dynamic rescheduling trigger strategy (HDRS) with four judgment mechanisms has been developed. The decision-making method and rescheduling trigger strategy solve the problem of how and when to reschedule for the dynamic scheduling problem. The data experiment results show that the trained DRL decision-making model can provide timely feedback on the adjusted scheduling arrangements for different-scale order problems. The proposed dynamic-scheduling decision-making method and rescheduling trigger strategy can achieve high responsiveness, quick feedback, high quality, and high stability for flexible manufacturing process scheduling decision making under sudden disturbance.
A Privacy-Preserving Reputation Evaluation System with Compressed Revocable One-Time Ring Signature (CRORS)
Authors: Han Xu , Zhang Dawei
Published: December 2024

Reputation evaluation systems are vital for online platforms, helping users make informed choices based on the trustworthiness of products, services, or individuals. Ensuring privacy and trust in these systems is critical to allow users to provide feedback without fear of retribution or identity exposure. The ring signature (RS), enabling anonymous group-based signing, has garnered attention for building secure and private reputation systems. However, RS-based systems face significant challenges, including the inability to identify malicious users who repeatedly sign the same message, the lack of mechanisms to reveal identities involved in unlawful activities, and a linear growth in signature size with the number of ring members, which poses storage challenges for certain applications. Addressing these limitations, we propose a compressed revocable one-time ring signature (CRORS) scheme leveraging compressible proofs under the Diffie–Hellman Decision and Discrete Logarithm assumptions in the random oracle model. CRORS ensures anonymity, unforgeability, one-time linkability, non-slanderability, and revocability. The one-time linkability feature prevents double-signing, while revocability enables identity disclosure for regulatory enforcement. Additionally, the signature size is reduced to O(logn), significantly enhancing storage efficiency. These improvements make CRORS particularly suitable for blockchain-based reputation systems with ever-growing storage demands. Theoretical analysis validates its effectiveness and practicality.
Mathematical Dimensional Synthesis of Four-Bar Linkages Based on Cognate Mechanisms
Authors: Soriano-Heras Enrique , Pérez-Carrera Carlos , Rubio Higinio
Published: December 2024

In the field of mechanical engineering, understanding mechanisms is essential for designing and developing devices and systems. Mechanisms, composed of interconnected elements, transform the energy applied to the input link into motion or force in the output link. Mechanisms are found in a wide variety of machines, from industrial machines to household machines. In this paper, a mechanism synthesis method is developed that can model four-bar linkages and build their cognate mechanisms to be able to select the mechanism that best suits the required work. Studying four-bar mechanisms offers a strong foundation for grasping more complex mechanical systems. The concepts and principles learned from four-bar mechanisms are widely applicable to advanced mechanical systems, making them a crucial starting point in mechanical engineering education and research. The mechanism synthesis method proposed in this article is organized into three main sections. The first section provides a comprehensive overview of the theoretical and mathematical foundations required for modeling mechanisms, laying the groundwork for understanding the subsequent calculations. The second section delves into the process of obtaining and analyzing the initial mechanism and constructing cognate mechanisms, detailing the procedures and algorithms used for modeling and calculating the coupling curve. Finally, the third section discusses the practical implementation of the method, including the graphical representation of mechanisms and a comparative analysis of the solutions obtained, assessing dimensional differences, design and manufacturing efficiency, and their suitability for various practical applications. The proposed four-bar mechanism synthesis method serves as a valuable tool for mechanism design, offering versatile and adaptable solutions that can optimize both technical performance and economic viability across a wide range of engineering applications.