Search Results (37,399)

This study valorizes onion peel, an agro-industrial by-product rich in phenolic compounds and structural carbohydrates, for the development of cassava starch-based biodegradable films. The films were prepared using the solution casting method; a cassava starch matrix was mixed with a 2.5% glycerol solution and heated to 85 °C for 30 min. A separate solution of onion peel powder (OPP) in distilled water was prepared at 25 °C. The two solutions were then combined and stirred for an additional 2 min before 25 mL of the final mixture was cast to form the films. Onion peel powder (OPP) incorporation produced darker and more opaque films, suitable for packaging light-sensitive foods. Film thickness increased with OPP content (0.138–0.218 mm), while moisture content (19.2–32.6%) and solubility (24.0–25.2%) decreased. Conversely, water vapor permeability (WVP) significantly increased (1.69 × 10⁻⁹–2.77 × 10⁻⁹ g·m⁻¹·s⁻¹·Pa⁻¹; p < 0.0001), reflecting the hydrophilic nature of OPP. Thermal analysis (TGA/DSC) indicated stability up to 245 °C, supporting applications as food coatings. Morphological analysis (SEM) revealed OPP microparticles embedded in the starch matrix, with FTIR and XRD suggesting electrostatic and hydrogen–bond interactions. Mechanically, tensile strength improved (up to 2.71 MPa) while elongation decreased (14.1%), indicating stronger but less flexible films. Biodegradability assays showed slightly reduced degradation (29.0–31.8%) compared with the control (38.4%), likely due to antimicrobial phenolics inhibiting soil microbiota. Overall, OPP and cassava starch represent low-cost, abundant raw materials for the formulation of functional biopolymer films with potential in sustainable food packaging. Full article

Digital transformation in higher education necessitates a central role for university faculty, yet there is a lack of comprehensive tools to measure their actual pedagogical use of technology. This study aims to refine the definition of a composite indicator to evaluate mobile technology adoption among social science university teachers. Using the results of the validated MOBILE-APP questionnaire, administered to a sample of N = 295 teachers from various social science degree programs, we employed multilevel structural equation modeling (SEM) to develop and implement a synthetic indicator for assessing mobile technology adoption levels among educators. The analysis of the considered factors (motivation, training, tools, and use) revealed differences in mobile technology adoption based on degree program, age, and previous experience. High motivation, training, use of institutional tools, and propensity for use promote the adoption of mobile technologies. Three levels of mobile technology adoption are identified and characterized. This synthetic indicator can be used both technically and socially to track the evolution of mobile technology adoption, enabling comparative analyses and longitudinal assessments that inform strategic decisions in training, infrastructure, and curriculum development. This research represents a step forward in the development of quantitative indicators and the assessment of research practices. Full article

Expansive agents (CaO, MgO, C₄A₃Š) were incorporated into coal gangue-slag-fly ash based geopolymer (CSFG). The influence of expansive agents on the properties and microstructure of CSFG was investigated by macroscopic tests including setting time, compressive strength, and shrinkage values, along with microstructural tests including XRD, FTIR, SEM-EDS, and BET. Results showed that CaO and MgO added separately and their combination exhibited similar trends, with CaO added separately yielding the most favorable outcome. In comparison to the control group, the sample with 7% CaO reduced initial and final setting times by 43.6% and 52.8%, increased 28 d compressive strength by 12.6%, and decreased 28 d drying shrinkage and autogenous shrinkage values by 43.5% and 29.9%, respectively. Moderate MgO and CaO enhanced dissolution of precursors (e.g., coal gangue, fly ash), promoting formation of C-A-S-H gel, CaCO₃, and periclase. Incorporating 3% C₄A₃Š shortened initial and final setting times by 41.3% and 17.8%, improved 28 d compressive strength by 32.2%, but increased 28 d drying and autogenous shrinkage values by 58.3% and 12.8%. Exceeding 3% content significantly reduced 3 d strength. Excessive C₄A₃Š promoted rapid ettringite (AFt) formation, leading to microcracking. Correction prediction models for drying shrinkage strain and autogenous shrinkage strain of CSFG were developed, demonstrating good agreement between predictive and actual values. Full article

Mineral water content strongly depends on the geologic layer characteristics. Therefore, the aim of the present study is to make a comparison between two renowned mineral water sources in Romania, Borsec and Tusnad. Two public springs were selected from each location: Boldizsar (about 6600 L/day) and Lazar (about 500 L/day) from Borsec and Mikes (about 5000 L/day) and Young’s spring (about 600 L/day) from Tusnad. All investigated springs are naturally carbonated. Water properties were measured in situ and in laboratory for the collected samples; the results found that Borsec mineral water has a pH of about 7.5, while Tusnad mineral water is slightly acid (pH = 6.5). TDS strongly depends on the spring’s flow (for instance, Boldizsar has a TDS of about 900 mg/L, while Lazar has a TDS of about 1529 mg/L due to its high mineralization, while Young’s spring has a TDS of 165 mg/L due to its low mineralization, although it has low flow). Borsec mineral water has a lower salinity of about 1.22 PSU, while Tusnad water has a salinity of about 2 PSU, caused by a high amount of Na and Fe ions. Mineral waters dissolve ions from the geological layers, which react with carbonic acid during drying, generating specific crystallized compounds. The crystallized matter was investigated using XRD coupled with mineralogical optical microscopy (MOM); their microstructural features were observed using SEM coupled with elemental spectroscopy. Borsec water generates mainly Ca, Mg, and Na minerals like calcite, aragonite, pseudo-dolomite, natron, and traces of halite. Tusnad mineral waters have significant amounts of Ca, but also have Fe and much more Cl, since calcite and aragonite are mixed up with large amounts of halite and iron compounds. It looks like the presence of iron ions in the Tusnad mineral water collected from Mikes and Young’s spring explains the acidic pH. All these aspects are useful for further investigation regarding specific therapeutic purposes like chronic colitis and biliary lithiasis symptom amelioration (Boldizsar), chronic colitis, and enterocolitis symptoms (Lazar). Tusnad waters, like the water from Mikes spring, are recommended for anemia and neurasthenia, while Young’s spring is recommended for renal lithiasis amelioration. Full article

Although many studies have examined reaction zones in groundwater–seawater mixing areas, little attention has been given to how subsurface processes drive changes in iron (Fe) precipitation over time and space. This gap has limited our understanding of the “iron curtain” phenomenon in coastal aquifers. To address this, this study developed a reactive transport model to investigate how porosity evolves during the oxidative precipitation of Fe(II) in porous media. The model incorporates the dynamic effects of tortuosity, diffusivity, and surface area as minerals accumulate. Validation experiments, conducted with syringe tests that simulated Fe precipitation during freshwater–saltwater mixing, showed that precipitates formed mainly near the inlets, reflecting the development of a geochemical barrier at the groundwater–seawater interface. Scanning electron microscopy confirmed that Fe precipitates coated the surfaces of spherical particles. Numerical simulations further revealed that high Fe(II) concentrations drove pore clogging near the inlet, creating a dense precipitation zone akin to the iron curtain in coastal aquifers. At 10 mmol/L Fe(II), local clogging was observed, while at 100 mmol/L Fe(II), outflow rates (i.e., discharge) were substantially reduced. Together, the experiments and simulations highlight how hydrogeochemical processes influence hydraulic properties during the oxidative precipitation of Fe(II) in mixing zones. Full article

This study presents detailed microstructural observations of the mouthparts and sensory organs of adult cicadomorphan species, obtained using scanning electron microscopy (SEM). Despite microstructural variation, the overall morphology of the mouthparts, comprising a three-segmented labium and a bundle of interlocking stylets (maxillae and mandibles), is highly conserved across species, supporting its evolutionary significance in sap feeding from floem, xylem, or epidermis cells. Variations in the number and shape of mandibular stylet barbs likely reflect adaptations to different host plant tissues. The presence of an identical dual interlocking system between the maxillary stylets, which is found consistently across taxa, enhances functional stability during feeding and indicates a conserved mechanism among cicadomorphans. The species studied exhibit two distinct types of salivary canal closure: hooked and T-shaped. The latter potentially represents a state linked to specialised feeding strategies, such as sap xylem feeding. On the labial tip, there are different shapes of the anterior sensory fields. This area hosts a complex array of sensilla of different numbers, including gustatory (sensilla peg, PS1 and PS2, basiconica, BS3, double basiconica, DB), olfactory (finger–like, FLS) and thermo-hygroreceptive (sensillum dome-shaped, DS, and coeloconicum, CS) types, which facilitate host detection and feeding site selection. In the posterior sensory field, sensilla contact-chemosensory (sensilla basiconica, BS1 and BS2, and sensillum trichoideum, TS) are present. Mechanosensilla chaetica (CH1–CH3) are widely distributed on the last labial segment and may contribute to labium positioning. These findings emphasise the presence of both conserved and specialised morphological traits reflecting evolutionary and ecological diversification within Cicadomorpha. Full article

This study investigates the influence of technostress (Tech) on the well-being (WB) of employees in manufacturing sectors employing Industry 4.0 in Turkey, examining the effect of work exhaustion (WE) as a mediator in the association between technostress and well-being. How digital leadership (Dg) moderates these relationships is analyzed and discussed accordingly. This article also presents strategies for digital leaders to mitigate employees’ technostress in the digital transformation era and discusses their positive role. Using the Job Demands–Resources (JD-R) framework and Conservation of Resources (COR) theory, data were gathered from 329 workers employed at three manufacturing firms located in Istanbul. Structural equation modeling (SEM) was employed to test this study’s hypothesis. The results indicate that increased technostress notably reduces employee well-being, primarily because it heightens work exhaustion. Moreover, robust digital leadership effectively lessens these negative impacts, underscoring its value in managing technological stress. This research explains the importance of the Sustainable Development Goal (SDG 3) for better health and well-being practices in workplaces. It suggests practical implications for organizations, including developing digital leadership skills, routinely assessing technostress, and applying targeted actions to sustain employee health during digital shifts. Full article

This study investigates hotel employees’ perceptions of AI-driven human resource (HR) management systems within the Accor Group’s properties across three major European cities: Paris, Berlin, and Amsterdam. These diverse urban contexts, spanning a broad portfolio of hotel brands from luxury to economy, provide a rich setting for exploring how AI integration affects employee attitudes and work–life balance. A total of 437 employees participated in the survey, offering a robust dataset for structural equation modeling (SEM) analysis. Exploratory factor analysis identified two primary factors shaping perceptions: AI Perceptions, which encompasses employee views on AI’s impact on job performance, communication, recognition, and retention, and balanced management, reflecting attitudes toward fairness, personal consideration, productivity, and skill development in AI-managed environments. The results reveal a complex but optimistic view, where employees acknowledge AI’s potential to enhance operational efficiency and career optimism but also express concerns about flexibility loss and the need for human oversight. The findings underscore the importance of transparent communication, contextual sensitivity, and continuous training in implementing AI systems that support both organizational goals and employee well-being. This study contributes valuable insights to hospitality management by highlighting the relational and ethical dimensions of algorithmic HR systems across varied organizational and cultural settings. Full article

This study aimed to test the reliability of seven functional performance tests in amateur trail runners, including ankle mobility, balance, hopping, and countermovement jump (CMJ) tests. The sample consisted of 35 runners who were evaluated in two sessions separated by 7 to 14 days, which varied due to participants’ scheduling constraints. Relative reliability was assessed using the Intraclass Correlation Coefficient (ICC, which indicates consistency between repeated measures), the Standard Error of Measurement (SEM, which reflects measurement precision), and the Minimal Detectable Change (MDC, which represents the smallest real change beyond measurement error). The results show high reliability in almost all tests. The Lunge Test obtained an ICC of 0.990 and 0.983 for distance, and 0.941 and 0.958 for angular measurements in both legs. The Hop Tests showed moderate reliability with ICC above 0.7 In contrast, the Y Balance Test demonstrated lower reliability, with ICC values ranging from 0.554 to 0.732. The CMJ test showed good reliability, with an ICC ranging from 0.753 to 0.894, an SEM between 5.79% and 11.3%, and an MDC ranging from 15.54% to 31.44%, making it useful for assessing lower limb explosive strength. Both tests presented comparatively higher error values, which should be considered when interpreting individual changes. These findings support the use of these tests as valid and reliable tools for evaluating ankle dorsiflexion, balance, functional symmetry, and lower limb explosive strength in amateur trail runners, prior to training programs or injury prevention strategies, provided that standardized protocols and validated measuring instruments are used. Full article

Accelerated artificial aging of zinc oxide (ZnO)-based acrylic artists’ paint, filled with calcium carbonate (CaCO₃) as an extender, was carried out for a total of 1963 h (~8 × 10⁷ lux·h), with assessments at specific intervals. The total color difference ΔE* was <2 (CIELab-76 system) over 1725 h of aging, while the human eye notices color change at ΔE* > 2. Oxidative degradation of organic components in the paint to form volatile products was revealed by attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy, micro-Raman spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). It appears that deep oxidation of organic intermediates and volatilization of organic matter may be responsible for the relatively small value of ΔE* color difference during aging of the samples. To elucidate the degradation pathways, principal component analysis (PCA) was applied to the spectral data, revealing: (1) the catalytic role of ZnO in accelerating photodegradation, (2) the Kolbe photoreaction, (3) the decomposition of the binder to form volatile degradation products, and (4) the relative photoinactivity of CaCO₃ compared with ZnO, showing slower degradation in areas with a higher CaCO₃ content compared with those dominated by ZnO. These results provide fundamental insights into formulation-specific degradation processes, offering practical guidance for the development of more durable artist paints and conservation strategies for acrylic artworks. Full article

We evaluated for the morphology and growth behavior of IMC grain according to number of reflows of solder cap pure Sn microbumps. In the structure of Ni barrier/Cu layer between Cu pillar and pure Sn, solder cap pure Sn on the top layer was analyzed for the behavior change of IMC grain according to the number of reflows. The height and diameter of the bumps on the wafer were designed to be 40 μm and 30 μm, respectively. The vertical structure of the microbump consisted of Ti/Cu (1000 Å/2000 Å), Cu pillar (20 µm), Ni barrier (3 µm), and Cu (1 µm). The overall height of the bump is about 40 μm. Additionally, the height of the solder cap pure Sn as the last layer is 20 μm. The diameter of the bump is 30 μm. It was formed using plating. After plating to solder cap Sn, it was finally formed for the microbump using reflow. Samples were prepared according to the number of reflows (1, 3, 5, 7, and 9). To observe the grain morphology of the IMC, the pure Sn on the upper layer (solder cap) was removed using SupraBond RO-22 etchant. In the removed state, the morphology of the IMC grain was evaluated to the inside surface of bump using SEM and a 3D scope. The average number of IMC grains decreased linearly during reflow cycles 1 to 5 and then gradually decreased during reflow cycles 7 to 10. The average surface area of IMC grains was 18.243 μm when reflow was performed once. The average surface area of IMC grains increased proportionally for reflow cycles 1 to 10. Based on the experimental results, when the count of reflow was performed more than 10 times, it was confirmed that the solder cap pure Sn was reduced by more than 50% due to the increase in the area of IMC grain. Full article

Due to the rising atmospheric carbon dioxide levels driven by human activity, extensive scientific efforts have been dedicated to developing methods aimed at reducing its concentration in the atmosphere. A novel approach involves using hydrates as a long-lasting reservoir of CO₂ sequestration. This review provides an initial overview of hydrate characteristics, their formation mechanisms, and the experimental techniques commonly employed for their characterization, including X-ray, Raman spectroscopy, cryoSEM, DSC, and molecular dynamic simulation. One of the main challenges in CO₂ sequestration via hydrates is the requirement of high pressures and low temperatures to stabilize CO₂ molecules within the hydrate crystalline cavities. However, deviations from classical temperature-pressure phase diagrams observed in natural and engineered environments can be explained by considering that hydrate stability and formation are primarily governed by chemical potentials, not just temperature and pressure. Activity, which reflects concentration and non-ideal interactions, greatly influences chemical potentials, emphasizing the importance of solution composition, salinity, and additives. In this context the role of promoters and inhibitors in facilitating or hindering hydrate formation is discussed. Furthermore, the review presents an overview of the impact of marine sediments and naturally occurring compounds on CO₂ hydrate formation, along with the sampling methodologies used in sediments to determine the composition of these natural compounds. Special attention is given to the effect and chemical characterization of dissolved organic matter (DOM) in marine aquatic environments. The focus is placed on the key roles of various natural occurring molecules, such as amino acids, protein derivatives, and humic substances, along with the analytical techniques employed for their chemical characterization, highlighting their central importance in the CO₂ gas hydrates formation. Full article

By employing thin section analysis, scanning electron microscopy (SEM), homogenization temperatures of fluid inclusions, and carbon–oxygen isotope analysis of carbonate cements, this study conducted a temporal-quantitative investigation into the porosity evolution of relatively high-quality reservoirs in the Second Member of the Xujiahe Formation (Xu-2 Member) in the Xinchang area of western Sichuan. The analysis focused on quantifying porosity loss due to compaction, cementation, and porosity enhancement from dissolution. Results indicate that compaction exerted the most significant impact on reservoir quality in the Xu-2 Member, causing over 70% of total porosity loss. Cementation processes, including carbonate cements, silica cements, and authigenic chlorite, further degraded reservoir properties. Authigenic chlorite precipitated earliest at burial depths of 600–800 m, while authigenic quartz and carbonate cements persistently affected the reservoir at depths of 2000–5000 m, reducing porosity by at least 10% (up to 21%). Dissolution processes initiated at approximately 3500 m burial depth, generating secondary porosity of ≥2%, with a maximum increase of 16%. Integrating these findings with the natural gas accumulation history, the coupling relationship between pore evolution and gas accumulation was elucidated. The study reveals that reservoir tightness in the Xu-2 Member developed at burial depths of 4050–5300 m, with large-scale gas accumulation predominantly occurring prior to reservoir densification. The findings provide critical guidance for identifying high-quality tight sandstone reservoirs and optimizing exploration targets in the Xu-2 Member of the Xinchang area, Western Sichuan Basin, thereby supporting efficient development of regional tight gas resources. Full article

Fe-CNT composites were synthesized via mechanical ball milling, incorporating varying amounts of carbon nanotubes (CNTs) into iron powder at concentrations of 1wt%, 2wt%, and 3wt%. The impact of different CNT contents on the phase structure, microstructure, and magnetic properties of the composites was examined. Raman spectroscopy and X-ray diffraction (XRD) analyses revealed that despite some damage, CNTs retained a predominantly one-dimensional nanostructure post-ball milling. Moreover, an increase in CNT content led to a gradual rise in grain size and lattice strain of the iron powder, attributed to the formation of solid solutions and iron–carbon compounds. Scanning electron microscopy (SEM) observations demonstrated that the majority of CNTs were integrated within the iron matrix particles, with a minority either partially embedded or entirely unembedded on the iron powder surface. With higher CNT concentrations, local CNT agglomeration emerged and intensified. Vibrating sample magnetometer (VSM) measurements indicated that Fe-CNT composites exhibited enhanced saturation magnetization (2.25%) and reduced coercivity (91.74%) compared to pure iron, underscoring the potential of CNTs in enhancing the magnetic properties of iron powder. Full article

This study distinguished male and female individuals by wing morphology (males with long wings, females with short wings) and investigated sexual dimorphism in the chemosensory system of Blaptica dubia through integrated ultrastructural and transcriptomic analyses. Scanning electron microscopy (SEM) was used to characterize the type, number, and distribution of antennal sensilla, while Illumina HiSeq sequencing, Gene Ontology/Kyoto Encyclopedia of Genes and Genomes (GO/KEGG) annotation, and Quantitative Real-time Reverse Transcription Polymerase Chain Reaction (qRT-PCR) validation were employed to analyze sex-specific gene expression profiles. Both sexes exhibited Böhm’s bristles, chaetic, trichoid, and basiconic sensilla. Males showed significantly more chaetic sensilla on the pedicel and longer type I/II chaetic sensilla on the flagellum, whereas females had longer ST2 sensilla. Basiconic sensilla were predominantly flagellar-distributed and more abundant/longer in males. No sexual differences were observed in Böhm’s bristles. Transcriptomics revealed 5664 differentially expressed genes (DEGs) (2541 upregulated; 3123 downregulated), enriched in oxidation-reduction, extracellular space, lysosome, and glutathione metabolism. KEGG analysis identified five key pathways: lysosome, glutathione metabolism, cytochrome P450-mediated xenobiotic/drug metabolism, and ascorbate/aldarate metabolism. Among 11 chemosensory-related DEGs, chemosensory proteins (CSPs) and odorant binding proteins (OBPs) were downregulated in males, while gustatory receptors (GRs), olfactory receptors (Ors), and ionotropic receptors (IRs) were upregulated. These results demonstrate profound sexual dimorphism in both antennal sensilla morphology and chemosensory gene expression, suggesting divergent sex-specific chemical communication strategies in Blaptica dubia, with implications for understanding adaptive evolution in Blattodea. Full article