Search Results (89,902)

Tribological performance is critical for the longevity and efficiency of machined components in industries such as aerospace, automotive, and biomedical. This study investigates whether electrical discharge machining recast layers can serve as a cost-effective and time-efficient alternative to conventional tungsten inert gas cladding coatings for enhancing surface properties. The samples were prepared using electrical discharge machining and tungsten inert gas cladding. For electrical discharge machining, various combinations of electrical and non-electrical parameters were applied using Taguchi’s L18 orthogonal array. Similarly, tungsten inert gas cladding coatings were prepared using a suitable combination of current, voltage, powder size, and speed. The samples were characterized using, scanning electron microscopy, optical microscopy, microhardness testing, tribological testing, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis and profilometry. The electrical discharge machining recast layers exhibited superior tribological performance compared to tungsten inert gas cladding coatings. This improvement is attributed to the formation of carbides, such as TiC and Ti₆C_3.75. The coefficient of friction and specific wear rate were reduced by 11.11% and 1.57%, respectively, while microhardness increased by 10.93%. Abrasive wear was identified as the predominant wear mechanism. This study systematically compares electrical discharge machining recast layers with tungsten inert gas cladding coatings. The findings suggest that optimized electrical discharge machining recast layers can serve as effective coatings, offering cost and time savings. Full article

Background: Growing disparities in development, governance, and logistics performance across countries pose challenges for global policymaking and Sustainable Development Goal (SDG) monitoring. This study proposes a classification of 137 countries based on multiple structural dimensions. The dataset for 2023 includes six components of the Logistics Performance Index (LPI), six dimensions of the Worldwide Governance Indicators (WGIs), and four proxies of the Human Development Index (HDI). Methods: The Uniform Manifold Approximation and Projection (UMAP) technique was used to reduce dimensionality and allow for meaningful clustering. Based on the reduced space, the K-means algorithm was employed to group countries with similar development characteristics. Results: The classification process allowed the identification of three distinct groups of countries, supported by a Hopkins statistic of 0.984 and an explained variance ratio of 87.3%. These groups exhibit structural differences in the quality of governance, logistics capacity, and social development conditions. Internal consistency checks and multivariate statistical analyses (ANOVA and MANOVA) confirmed the robustness and statistical significance of the clustering. Conclusions: The resulting classification offers a practical analytical tool for policymakers to design differentiated strategies aligned with national contexts. Furthermore, it provides a data-driven approach for comparative monitoring of the SDGs from an integrated and empirical perspective. Full article

Hydraulic asphalt concrete (HAC) is susceptible to performance deterioration under long-term water immersion. This study conducted compressive, tensile, and bending tests on HAC under various immersion times (0–96 h), established a multidimensional performance evaluation method, and developed a service-life prediction model for long-term water immersion. The average relative error between test values and predicted values was less than 5%, validating the model’s effectiveness and applicability. Results indicate that the rate of mechanical property degradation exhibits stage-dependent characteristics with immersion time, and the water damage resistance of alkaline aggregate is significantly superior to that of acidic aggregate. The predictive model shows that after 192 h of immersion, the retention rate of key mechanical properties for the alkaline aggregate reaches 92.71%, while that for acidic aggregate was only 73.85%. This study establishes a predictive model that provides a theoretical basis for assessing the lifespan of HAC under long-term immersion conditions. Full article

Soybean (Glycine max (L.) Merrill) is a major oilseed crop rich in phytosterols and tocopherols, compounds associated with functional and nutritional properties of vegetable oils. This study aimed to apply, for the first time, Independent Component Analysis (ICA) to discriminate the composition of phytosterols (β-sitosterol, campesterol, stigmasterol) and tocopherols (α, β, γ, δ) in 20 soybean genotypes—14 non-transgenic and six transgenic—cultivated in two major producing regions of Paraná state, Brazil (Londrina and Ponta Grossa). Lipophilic compounds were extracted from soybean seeds, quantified via gas chromatography and HPLC, and statistically analyzed using ICA with the JADE algorithm. The extracted independent components successfully differentiated soybean varieties based on phytochemical profiles. Notably, transgenic cultivars from Ponta Grossa exhibited higher levels of total tocopherols, including α- and β-tocopherol, while conventional cultivars from both regions showed elevated phytosterol content, particularly campesterol and stigmasterol. ICA proved to be a powerful unsupervised method for visualizing patterns in complex compositional data. These findings highlight the significant influence of genotype and growing region on the nutraceutical potential of soybean, and support the use of multivariate analysis as a strategic tool for cultivar selection aimed at enhancing functional quality in food applications. Full article

Obtaining the echo of individual fish is an important prerequisite for fisheries acoustic applications, such as in situ measurement of fish target strength and assessment of fish abundance using the counting method. It is also the foundation for evaluating the growth status of farmed fish and managing aquaculture risks. The density of farmed fish populations is typically higher, and such high-density aquaculture further increases the difficulty of obtaining individual fish echoes in practical applications. Building upon previous research and considering the behavioral characteristics of fish in aquaculture settings, this study conducted performance simulations, live fish experiments in simulated aquaculture cages, and comparative evaluations of three individual fish broadband echo detection methods based on a broadband signal system: the amplitude pulse width method (APM) based on echo envelopes, the peak detection and time delay estimation method (PDM), and the peak time delay combined with instantaneous frequency method (PDIM). This study assumed a dorsolateral fish orientation, which limits its research scope and applicability. The results showed that the PDIM achieved a detection accuracy of 78.34% and a false recognition rate of 1.32%. The APM based on echo envelopes was insensitive to individual fish echoes and had lower recognition accuracy. The PDM exhibited better individual fish echo capture capabilities, while the PDIM demonstrated superior overlapping echo rejection capabilities. Full article

This study investigated the cognitive profiles of Italian university students with dyslexia using the WAIS-IV, comparing them to peers without specific learning disorders. Seventy-one participants took part: 36 with a diagnosis of dyslexia and 35 matched controls. While dyslexic adults showed lower Full Scale IQ (FSIQ) scores compared to controls, their scores remained within the average range. They showed deficits in Working Memory Index (WMI) and Processing Speed Index (PSI) but performed similarly to controls in Verbal Comprehension Index (VCI) and Perceptual Reasoning Index (PRI). Significant group differences also emerged in Arithmetic Reasoning, Symbol Search, and Coding subtests. Logistic regression identified WMI and PSI as the most reliable predictors of dyslexia, showing a good predictive value in discriminating between adults with and without dyslexia. Additionally, dyslexic adults displayed lower Cognitive Proficiency Index (CPI) scores relative to their General Ability Index (GAI), and lower FSIQ scores compared to controls. Overall, dyslexic adults exhibit a distinctive cognitive profile with strengths and weaknesses. This pattern can aid in dyslexia diagnosis, particularly in individuals who have compensated through extensive reading experience in a highly regular orthography. Full article

Introduction: Vitamin D deficiency, a reversible cause of osteoporosis, is increasingly prevalent, showing varying degrees of severity that are notably pronounced among the growing population of multimorbid elderly patients. Given that the aging pancreas undergoes senescent processes leading to impaired function—which negatively impacts enteral vitamin D absorption and, consequently, elderly bone metabolism—a specific diagnostic and treatment approach is crucial. Our study aimed to determine the prevalence of vitamin D deficiency and exocrine pancreatic insufficiency (EPI) in orthogeriatric patients. We also evaluated differences in vitamin D deficiency severity between patients with normal and impaired pancreatic function. Furthermore, a short-term monitoring of vitamin D level increases after 12 days of substitution therapy in both groups aimed to inform osteoanabolic therapy for specific high-fracture-risk patients, assessing the influence of pancreatic function on substitution efficacy. Methods: We conducted a retrospective, monocentric cohort study, evaluating data from all patients hospitalized with manifest osteoporosis in an orthogeriatric department during a six-month spring/summer period. Demographic data, relevant comorbidities, the type of fracture, the amount of faecal elastase 1 (CALEX^® Cap Bühlmann), and the serum levels of 25-hydroxyvitamin D (25(OH)D) were assessed. Results: We found a high prevalence (70.6%) of vitamin D deficiency (25(OH)D < 30 µg/L) among all orthogeriatric patients. Of these, 16% met the criteria for mild to severe EPI. The group with normal exocrine pancreatic function showed a higher average vitamin D value, and their increase in vitamin D levels following short-term substitution was up to 100% greater compared to the group with impaired pancreatic function. Notably, 69% of women and 20% of men met the therapeutic threshold for specific osteoanabolic osteoporosis therapy, even without a T-score. Conclusions: Our findings reveal a very high prevalence of vitamin D deficiency and a high prevalence of EPI in orthogeriatric patients. Those with impaired exocrine pancreatic function exhibit lower baseline vitamin D levels and a diminished capacity for vitamin D absorption during short-term monitoring. These results have significant clinical implications for osteoporotic therapy, given that a substantial proportion of patients, particularly women, meet the criteria for specific osteoanabolic treatment. Full article

The present study explores the application of RNNs for the prediction and propagation of flood waves along a section of the Bârsa River, Romania, as a fast alternative to classical hydraulic models, aiming to identify new ways to alert the population. Five neural architectures were analyzed as follows: S-RNN, LSTM, GRU, Bi-LSTM, and Bi-GRU. The input data for the neural networks were derived from 2D hydraulic simulations conducted using HEC-RAS software, which provided the necessary training data for the models. It should be mentioned that the input data for the hydraulic model are synthetic hydrographs, derived from the statistical processing of recorded floods. Performance evaluation was based on standard metrics such as NSE, $R^2$ MSE, and RMSE. The results indicate that all studied networks performed well, with NSE and $R^2$ values close to 1, thus validating their capacity to reproduce complex hydrological dynamics. Overall, all models yielded satisfactory results, making them useful tools particularly the GRU and Bi-GRU architectures, which showed the most balanced behavior, delivering low errors and high stability in predicting peak discharge, water level, and flood wave volume. The GRU and Bi-GRU networks yielded the best performance, with RMSE values below 1.45, MAE under 0.3, and volume errors typically under 3%. On the other hand, LSTM architecture exhibited the most significant instability and errors, especially in estimating the flood wave volume, often having errors exceeding 9% in some sections. The study concludes by identifying several limitations, including the heavy reliance on synthetic data and its local applicability, while also proposing solutions for future analyses, such as the integration of real-world data and the expansion of the methodology to diverse river basins thus providing greater significance to RNN models. The final conclusions highlight that RNNs are powerful tools in flood risk management, contributing to the development of fast and efficient early warning systems for extreme hydrological and meteorological events. Full article

The stability of nitrogen gas foam hinders its applicability in petroleum applications. Fly ash nanoparticles and clay improve the N₂ foam stability, and flue gas foams provide a cost-effective solution for carbon capture, utilization, and storage (CCUS). This study examines the stability, volume, and bubble structure of foams formed using two anionic surfactants, sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS), along with the cationic surfactant cetyltrimethylammonium bromide (CTAB), selected for their comparable interfacial tension properties. Analysis of foam stability and volume and bubble structure was conducted under different CO₂/N₂ mixtures, with half-life and initial foam volume serving as the evaluation criteria. The impact of fly ash and clay on SDS-N₂ foam was also evaluated. The results showed that foams created with CTAB, SDBS, and SDS exhibit the greatest stability in pure nitrogen, attributed to low solubility in water and limited gas diffusion. SDS showed the highest foam strength attributable to its comparatively low surface tension. The addition of fly ash and clay significantly improved foam stability by migrating to the gas–liquid interface, creating a protective barrier that reduced drainage. Both nano fly ash and clay improved the half-life of nitrogen foam by 11.25 times and increased the foam volume, with optimal concentrations identified as 5.0 wt% for fly ash and 3.0 wt% for clay. This research emphasizes the importance of fly ash nanoparticles in stabilizing foams, therefore optimizing a foam system for enhanced oil recovery (EOR). Full article

The blended system of solid waste micro-powders is of great significance for the efficient utilization of recycled micro-powder. In this study, a ternary blended cementitious system composed of fly ash, slag, and recycled micro-powder was constructed, and its effects on the workability, mechanical properties, shrinkage performance, and microstructure of recycled mortar were systematically investigated. The experimental results show that with the increasing dosage of slag and recycled micro-powder (partially replacing cement and fly ash), the standard consistency water demand of the cementitious system decreases and the setting time is prolonged. When the replacement levels of recycled micro-powder and slag are both 10%, the 3-day, 7-day, and 28-day mechanical strengths of the mortar specimens are comparable to those of the reference group, with an increased flexural-to-compressive strength ratio and improved brittleness. SEM and mercury intrusion porosimetry (MIP) analyses revealed that systems incorporating low addition levels of recycled micro powder and slag powder exhibit calcium silicate hydrate (C-S-H) gel, acicular ettringite crystals, and a denser pore structure. However, at higher dosages (>10%), the porosity increases significantly and the pore structure deteriorates, resulting in reduced shrinkage performance. Overall, when the replacement rate of cement–fly ash by recycled micro-powder and slag is 10%, the ternary blended system exhibits optimal macroscopic performance and microstructure, providing a scientific basis for the resource utilization of solid waste. Full article

Euterpe precatoria Mart. is an increasingly important palm for subsistence and income generation in central and western Amazonia with growing demand for its fruit pulp, which is an alternative source of açaí juice for domestic and international markets. This study synthesizes current knowledge on its systematics, ecology, fruit production in natural populations, fruit quality, uses, population management, and related areas, identifying critical research gaps. A systematic literature survey was conducted across databases including Web of Science, Scopus, Scielo, CAPES, and Embrapa. Of 1568 studies referencing Euterpe, 273 focused on E. precatoria, with 90 addressing priority themes. Genetic diversity studies suggest the E. precatoria may represent a complex of species. Its population abundance varies across habitats: the highest variability occurs in terra firme, followed by baixios and várzeas. Várzeas exhibit greater productivity potential, with more bunches per plant and higher fruit weight than baixios; no production data exist for terra firme. Additionally, E. precatoria has higher anthocyanin content than E. oleracea, the primary commercial açaí species. Management of natural populations and cultivation practices are essential for sustainable production; however, studies in these fields are still limited. The information is crucial to inform strategies aiming to promote the sustainable production of the species. Full article

In recent years, most proposed digital image encryption algorithms have primarily focused on encrypting raw pixel data, often neglecting the integration with image compression techniques. Image compression algorithms, such as JPEG, are widely utilized in internet applications, highlighting the need for encryption methods that are compatible with compression processes. This study introduces an innovative color image encryption algorithm integrated with JPEG compression, designed to enhance the security of images susceptible to attacks or tampering during prolonged transmission. The research addresses critical challenges in achieving an optimal balance between encryption security and compression efficiency. The proposed encryption algorithm is structured around three key compression phases: Discrete Cosine Transform (DCT), quantization, and entropy coding. At each stage, the algorithm incorporates advanced techniques such as block segmentation, block replacement, DC coefficient confusion, non-zero AC coefficient transformation, and RSV (Run/Size and Value) pair recombination. Extensive simulations and security analyses demonstrate that the proposed algorithm exhibits strong robustness against noise interference and data loss, effectively meeting stringent security performance requirements. Full article

Municipal wastewaters pose a severe risk to the environment and human health when discharged untreated. This is due to their high content of pathogens, such as viruses and bacteria, which can cause diseases like cholera. Herein, the research and development of porphyrin-modified polyethersulfone (PES) ultrafiltration (UF) membranes was conducted to improve bacterial inactivation in complex municipal wastewater and enhance the fouling resistance and filtration performance. The synthesis and fabrication of porphyrin nanofillers and the resultant membrane characteristics were studied. The incorporation of porphyrin-based nanofillers improved the membrane’s hydrophilicity, morphology, and flux (247 Lm⁻² h⁻¹), with the membrane contact angle (CA) decreasing from 90° to ranging between 58° and 50°. The membrane performance was monitored for its flux, antifouling properties, reusability potential, municipal wastewater, and humic acid. The modified membranes demonstrated an effective application in wastewater treatment, achieving notable antibacterial activity, particularly under light exposure. The In-BP@SW/PES membrane demonstrated effective antimicrobial photodynamic effects against both Gram-positive S. aureus and Gram-negative E. coli. It achieved at least a 3-log reduction in bacterial viability, meeting Food and Drug Administration (FDA) standards for efficient antimicrobial materials. Among the variants tested, membranes modified with In-PB@SW nanofillers exhibited superior antifouling properties with flux recovery ratios (FRRs) of 78.9% for the humic acid (HA) solution and 85% for the municipal wastewater (MWW), suggesting a strong potential for long-term filtration use. These results highlight the promise of porphyrin-functionalized membranes as multifunctional tools in advanced water treatment technologies. Full article

Rhabditis (Rhabditella) axei is a predominantly free-living nematode commonly found in sewage systems and decomposing organic matter. While primarily saprophytic, it has been documented as an opportunistic pathogen in human urinary and gastrointestinal tracts. The Chinese red panda (Ailurus styani), a rare and protected species in China, has not previously been reported as a host for Rhabditis (Rhabditella) spp. infections. This study reports the first documented occurrence of R. axei in red panda feces, unambiguously confirmed through integrative taxonomic approaches combining morphological and molecular analyses. The nematodes exhibited key morphological features consistent with R. axei, including a cylindrical rhabditiform esophagus, sexually dimorphic tail structures, and diagnostic spicule morphology. Molecular analysis based on 18S-ITS-28S rDNA sequencing confirmed their identity, showing >99% sequence similarity to R. axei reference strains (GenBank: PP135624.1, PP135622.1). Phylogenetic reconstruction using 18S rDNA and ITS rDNA sequences placed the isolate within a well-supported R. axei clade, clearly distinguishing it from related species such as R. blumi and R. brassicae. The findings demonstrate the ecological plasticity of R. axei as a facultative parasite capable of infecting non-traditional hosts and further highlight potential zoonotic risks associated with environmental exposure in captive wildlife populations. Our results emphasize the indispensable role of molecular diagnostics in accurately distinguishing morphologically similar nematodes within the Rhabditidae family, while providing essential baseline data for health monitoring in both in situ and ex situ conservation programs for this endangered species. Full article

To address the central cracking problem in continuous casting slabs of 38CrMoAl steel, high-temperature tensile tests were performed using a Gleeble-3800 thermal simulator to characterize the hot ductility of the steel within the temperature range of 600–1200 °C. The phase transformation behavior was computationally analyzed via the Thermo-Calc software, while the microstructure, fracture morphology, and precipitate characteristics were systematically investigated using a metallographic microscope (MM), a field-emission scanning electron microscope (FE-SEM), and transmission electron microscopy (TEM). Additionally, the effects of different holding times and cooling rates on the microstructure and precipitates of 38CrMoAl steel were also studied. The results show that the third brittle temperature region of 38CrMoAl steel is 645–1009 °C, and the fracture mechanisms can be classified into three types: (I) in the α single-phase region, the thickness of intergranular proeutectoid ferrite increases with rising temperature, leading to reduced hot ductility; (II) in the γ single-phase region, the average size of precipitates increases while the number density decreases with increasing temperature, thereby improving hot ductility; and (III) in the α + γ two-phase region, the precipitation of proeutectoid ferrite promotes crack propagation and the dense distribution of precipitates at grain boundaries causes stress concentration, further deteriorating hot ductility. Heat treatment experiments indicate that the microstructures of the specimen transformed under water cooling, air cooling, and furnace cooling conditions as follows: martensite + proeutectoid ferrite → bainite + ferrite → ferrite. The average size of precipitates first decreased, then increased, and finally decreased again with increasing holding time, while the number density exhibited the opposite trend. Therefore, when the holding time was the same, reducing the cooling rate could increase the average size of the precipitates and decrease their number density, thereby improving the hot ductility of 38CrMoAl steel. Full article