Search Results (246)

Biodegradable composite materials enhanced with food waste for tribological applications are proposed in this article. Polymer materials used as matrices included polypropylene and polylactic acid, which, according to the manufacturers’ claims, were made entirely or partially from biodegradable raw materials. Additionally, the matrices were enhanced with three types of waste materials: powders derived from cherry and plum stones, and pomace extracted from flax seeds. The composites differed in the percentage content of filler (15 or 25 wt.%) and particle size (d < 400 µm or d > 400 µm). Thirty-minute block-on-ring friction tests were performed to determine frictional behaviour (when pairing with steel), and the wear mechanisms were analysed using optical microscopy and scanning electron microscopy, supplemented with Raman spectroscopy. A notable effect of cherry and plum stone fillers was observed as a reduction in motion resistance, as measured by the friction coefficient. This reduction was evident across all material configurations in polypropylene-based composites and was significant at the lowest concentrations and granulation in polylactic acid composites. The effect of flaxseed pomace filler was ambiguous for both composite bases. Full article

In this paper, a biologically congruent parallel mechanism (PM) inspired by the masticatory system of human beings has been proposed to recreate complete chewing behaviours in three-dimensional space. The mechanism is featured by direct constraints from the base (DCFB) to its end effector at two higher kinematic pairs (HKPs), which greatly raise its topological complexity. Meanwhile, friction effects occur at HKPs and actuators, causing wear and then reducing motion accuracy. Regarding these, an inverse dynamic model that can raise the computational efficiency and the modelling fidelity is proposed, being prepared to be applied to realise accurate real-time motion and/or force control. In it, Euler parameters are employed to express the motions of the constrained end effector, and Newton–Euler’s law is applied, which can conveniently incorporate friction effects at both HKPs and actuators into the dynamic model. Numerical results show that the time consumption of the model using Euler parameters is only approximately 23% of that of the model using Euler angles, and friction effects significantly increase the model’s nonlinearity. Further, from the comparison between the models of the target PM and its counterpart free of DCFB, these constraints sharply raise the modelling complexity in terms of the transformation between Euler parameters and Euler angles in the end effector and the computational cost of inverse dynamics. Full article

Nickel’s durability and catalytic properties make it essential in the aerospace, automotive, electronics, and fuel cell technology industries. Wastewater analysis typically relies on sensitive but costly techniques such as ICP-MS, AAS, and ICP-AES, which require complex equipment and are unsuitable for on-site testing. This study introduces a novel screen-printed electrode array with 16 chemically and, optionally, electrochemically coated Au electrodes. Its electrochemical response to Ni²⁺ was tested using Na₂SO₃ and ChCl-EG deep eutectic solvents as electrolytes. Ni²⁺ solutions were prepared from NiCl₂·6H₂O, NiSO₄·6H₂O, and dry NiCl₂. In Na₂SO₃, the linear detection ranges were 20–196 mM for NiCl₂·6H₂O and 89–329 mM for NiSO₄·6H₂O. High Ni²⁺ concentrations (10–500 mM) were used to simulate industrial conditions. Two linear ranges were observed, likely due to differences in electrochemical behaviour between NiCl₂·6H₂O and NiSO₄·6H₂O, despite the identical Na₂SO₃ electrolyte. Anion effects (Cl⁻ vs. SO₄²⁻) may influence response via complexation or ion pairing. In ChCl-EG, a linear range of 0.5–10 mM (R² = 0.9995) and a detection limit of 1.6 µM were achieved. With a small electrolyte volume (100–200 µL), nickel detection in the nanomole range is possible. A key advantage is the array’s ability to analyze multiple analytes simultaneously via customizable electrode configurations. Future research will focus on nickel detection in industrial wastewater and its potential in the multiplexed analysis of toxic metals. The array also holds promise for medical diagnostics and food safety applications using thiol/Au-based capture molecules. Full article

Alongside the general growth in gaming and esports, competitive simulated (sim) racing has specifically surged in popularity in recent years, leading to an increased demand for understanding performance. In recent work, braking-related metrics were identified among the key indicators of successful sim racing performance. While load cell sensors currently serve as the industry standard for brake hardware, sensors like the Hall sensor may provide another viable option. No study to date has compared the performance of these braking sensors. The aim of this study was to investigate whether sim racing performance differed when racing using a load cell or Hall brake sensor. Twenty (N = 20) experienced sim racers raced with both the load cell and Hall brake sensors (with load cell behaviour mimicked on the Hall sensor) in a repeated measures design. Paired samples t-tests, Wilcoxon-signed rank tests, and chi-square goodness-of-fit tests were used to test for differences in lap time, driving behaviour metrics, and subjective responses between the two sensors. Results showed that participants achieved faster lap times using the load cell brake sensor (average lap time (p = 0.071); fastest lap time (p = 0.052)) and displayed braking behaviour more aligned with that of a “faster racer”. The differences observed may be potentially attributed to differences in in-game response curves between two brake sensors, which specifically may impact both the initial, and trail braking, phases. Full article

Background/Objectives: Metabolic syndrome (Mets) risk is influenced by both parents’ preconception lifestyle, yet most interventions target individuals rather than couples. True couples-based interventions that engage both partners equally remain rare. This study aimed to assess the feasibility and adherence of a 10-week lifestyle intervention delivered to heterosexual couples in the preconception period. Methods: This was a pre-post mixed-methods study involving eight nulliparous, cohabiting couples (N = 16 participants) planning a pregnancy within three years. Couples received tailored dietary and physical activity advice via remote sessions. Qualitative data were collected through post-intervention dyadic interviews and thematically analysed to explore participants’ experiences and perspectives on feasibility and adherence. Quantitative data on anthropometry, dietary intake (serves from five food groups), and sedentary behaviour were descriptively analysed. Wilcoxon signed-rank tests were used to assess changes in paired outcomes. Results: qualitative findings highlighted shared motivation, mutual accountability, cultural barriers, and the practicality of the intervention structure. All couples completed the intervention (100% retention). Among participants who required change, improvements were observed in all eight individuals for body mass index and in five out of seven individuals for waist-to-hip ratio. Statistically significant improvements were found in BMI (p = 0.027) and grain intake (p = 0.002), while other dietary and anthropometric changes were not significant. Dietary improvements were noted in 43 out of 80 observations across vegetables, fruits, grains, protein, and dairy intake. Sedentary hours were reduced in 12 of 16 participants, though increases in physical activity intensity were limited. Conclusions: A true-couples-based lifestyle intervention is feasible and acceptable in the preconception period. The approach shows potential for improving diet and reducing sedentary behaviour. Future research with a larger sample and longer duration is recommended to assess long-term effectiveness and broader applicability. Full article

We report on the preparation and characterization of a new family of hydrogen-bonded nematogenic liquid crystalline dimers. The dimers are supramolecular complexes that consist of a benzoic acid derivative, acting as the proton donor, featuring a spacer with seven methylene groups and a terminal decyloxy chain, paired with an azopyridine derivative as the proton acceptor. The latter was either fluorinated or nonfluorinated with variable alkoxy chain length. The formation of a hydrogen bond between the individual components was confirmed using FTIR and ¹H NMR spectroscopy. All supramolecules were investigated for their liquid crystalline behaviour via a polarized optical microscope (POM) and differential scanning calorimetry (DSC). All materials exhibit enantiotropic nematic phases as confirmed by X-ray diffraction (XRD) and POM investigations. The nematic phase range depends strongly on the degree and position of fluorine atoms. Additionally, the supramolecules demonstrated a rapid and reversible transition between the liquid crystal phase and the isotropic liquid state because of trans-cis photoisomerization upon light irradiation. Therefore, this study presents a straightforward approach to design photo-responsive nematic materials, which could be of interest for nonlinear optics applications. Full article

In this work, we employ a more thorough contractive condition to examine the stability and convergence behavior of an Jungck-type iterative scheme for a pair of non-self mappings in a Banach space. Our results show that this iterative scheme has a better rate of convergence as compared to all existing Jungck-type iterative schemes. The norm of a Banach space is symmetric with respect to the origin. Symmetry can significantly influence both the theoretical underpinnings and practical convergence behavior of iterative schemes. Furthermore, we show the convergence behaviour of various Jungck-type iterative schemes with an Jungck-KF iterative scheme through an example. We also prove the data-dependence result for our proposed iterative scheme for non-self-mapping. Additionally, we provide an application of the Jungck-KF iterative scheme related to Dynamic Market Equilibrium. Full article

The objective of the proposed work was to investigate the electrical performance of a 250 µm-thick 4H-SiC p-n junction detector after irradiation with DT neutrons (14.1 MeV energy) at high temperature (500 °C). The results showed that the current–voltage (I-V) characteristics of the unirradiated SiC detector were ideal, with an ideality factor close to 1.5. A high electron mobility (µ_n) and built-in voltage (V_bi) were also observed. Additionally, the leakage current remained very low in the temperature range of 298–523 K. High-temperature irradiation caused a deviation from ideal behaviour, leading to an increase in the ideality factor, decreases in the µ_n and V_bi values, and a significant rise in the leakage current. Studying the capacitance–voltage (C-V) characteristics, it was observed that neutron irradiation induced reductions in both Al-doped (p⁺-type) and N-doped (n⁻-type) 4H-SiC carrier concentrations. A comprehensive investigation of the deep defect states and impurities was carried out using deep-level transient spectroscopy (DLTS) in the temperature range of 85–750 K. In particular, high-temperature neutron irradiation influenced the behaviours of both the Z_1/2 and EH_6/7 traps, which were related to carbon interstitials, silicon vacancies, or anti-site pairs. Full article

In avian behavioural and spatial ecology, issues related to population density, territoriality, and philopatry are especially important. These are often interrelated. The aim of this study was to analyse these behaviours in shrikes inhabiting an acacia savanna in northern Namibia (400 ha). Population densities of one shrike and four bushshrike species were studied by means of the territory mapping method. About half of the study area had been modified by humans into cultivated fields, orchards, sport fields, and human settlements. This study was conducted in 2012/2013, 2017/2018, and 2019/2020. The most common species were the Black-backed Puffback (2.5 pairs/100 ha) and Crimson-breasted Shrike (1.9); the least common were the Southern White-crowned Shrike (0.8) and Brubru (1.0). Statistics for the Brown-crowned Tchagra indicated a density of 1.5 pairs/100 ha. While the density of the Brown-crowned Tchagra and Brubru remained stable over the years, the population densities of the Black-backed Shrike, Crimson-breasted Shrike, and Southern White-crowned Shrike showed a remarkable increase over the years 2012–2020. All bushshrike species showed a preference for patches of natural savanna vegetation. This was especially evident in the Crimson-breasted Shrike and the Brubru. However, the Southern White-crowned Shrike from the shrike family did not show this preference. The presented studies showed marked interspecific differences in territoriality and philopatry. Furthermore, even within the same species, marked temporal differences were shown in population density, probably also in philopatry. Within families, these behaviours may shape both resource competition and mate competition, while between families, these behaviours only shape resource competition. Full article

Understanding how organisms respond to temperature variation is essential for assessing and predicting their resilience and vulnerability to environmental and climate changes. Here, using a biparental care burying beetle (Nicrophorus vespilloides), we tested whether and how parental investment in carcass preparation and ambient temperature interact to influence subsequent parental care behaviour and reproductive success. We employed a 3 × 2 factorial experiment, manipulating the levels of parental investment in carcass preparation (Reduced, Control, and Elevated) and ambient temperatures (benign: 20 °C and harsh: 23 °C) in breeding pairs. We found the following: (1) Irrespective of ambient temperature, males in the Reduced group decreased their pre-hatching care. (2) Across all investment groups, both sexes under higher temperature reduced post-hatching care. (3) Carcass-preparation investment and ambient temperature interactively influenced reproductive success. Overall, the harsh temperature decreased reproductive success. Furthermore, beetle pairs experiencing reduced carcass-preparation investment produced fewer eggs and lighter broods, while those experiencing elevated carcass-preparation investment produced smaller and lighter broods. Our findings provide new insights into how temperature variation affects parental investment strategies and enhance our understanding of the phenotypic plasticity in reproductive strategies that animals employ to cope with climate change. Full article

Identifying illegal fishing activities from Automatic Identification System (AIS) data is difficult since AIS messages are broadcast cooperatively, the ship’s master controls the timing, and the content of the transmission and the activities of interest usually occur far away from the shore. This paper presents our work to predict ship types using AIS data from satellites: in such data, there is a pronounced imbalance between the data for different types of ships, the refresh rate is relatively low, and there is a misreporting of information. To mitigate these issues, our prediction algorithm only uses the sequence of ports the ships visited, as inferred from the positions reported in AIS messages. Experiments involving multiple machine learning algorithms showed that such port visits are informative features when inferring ship type. In particular, this was shown to be the case for the fishing vessels, which is the focus of this paper. We then applied a KD-tree to efficiently identify pairs of ships that are close to one another. As this activity is usually dangerous, multiple occurrences of such encounters that are linked to one ship sensibly motivate extra attention. As a result of applying the analysis approach to a month of AIS data related to a large area in Southeast Asia, we identified 17 cases of potentially illegal behaviours. Full article

Introduction: Sustainable nutrition is integral to environmental health and conservation. Gender and age differences influence dietary patterns, but their impact on the adoption of sustainable diets remains unclear. This study investigates the effects of a Mediterranean diet intervention on diet sustainability, focusing on gender and age differences. Methods: A cross-sectional study was conducted on 1666 participants (58.2% women) aged 18–75 years. Dietary preferences were assessed through food diaries and sustainability indices before and after the intervention. Participants followed a low-calorie Mediterranean diet for two months, with food diaries tracking their weekly consumption. Changes in sustainable and non-sustainable food consumption were analysed using paired t-tests and stratified by gender and age groups. Results: Men consumed significantly more meat and processed meat (p < 0.001), while women preferred low-fat yoghurt and whole grains (p < 0.01). Despite an increase in legume consumption (3.2%, p < 0.001), the overall sustainability index decreased due to a compensatory rise in meat consumption among men (p < 0.001), particularly in younger (<30) and older (>50) participants. Gender-related differences were observed, with female participants reporting a higher intake of foods classified as sustainable. However, significant cultural and palatability barriers limited the uptake of some sustainable foods such as tofu. Discussion: The intervention highlighted the challenges in promoting sustainable eating habits. Gender-targeted and age-specific strategies are critical to overcome barriers and support dietary improvements. Future interventions should incorporate cultural preferences and provide long-term support to achieve significant changes in behaviour. Conclusions: The Mediterranean diet intervention, conducted within an Italian cohort, highlighted both opportunities and challenges in promoting sustainable dietary transitions. Tailor-made approaches are essential to meet the different needs of various demographic groups. However, the effectiveness of nutrition programmes focusing on sustainability may depend on local food availability, cultural acceptance and dietary traditions. Full article

The oxidation behaviour of Ti alloys is a crucial aspect for structural components operating at high service temperature. The aim of this study is to identify the oxidation kinetics and mechanism of binary Ti-Cu alloys with a progressively higher amount of Cu with the alloys having a α + β lamellar structure. It is found that all the alloys followed a non-ideal (i.e., n ≠ 2) parabolic relationship, as controlled by anionic oxygen diffusion, with a distinct effect from both oxidation temperature and alloy chemistry. Specifically, faster oxidation kinetics are found both at higher temperatures and for higher Cu contents, resulting in the formation of thicker oxide scale layers. The oxidation mechanism primarily entails the formation of the stable TiO₂ rutile polymorph. However, transitions through metastable phases (e.g., anatase) and texturing of rutile are also revealed as dictated by the composition of the alloy at specific oxidation temperature/time pairs. Full article

This paper presents a comprehensive study on the vibration-based wear evolution characterisation by coupling the dynamic behaviour, surface roughness, and lubrication effects under rolling-sliding contact. Initially, a dynamic model is developed to examine the contact vibration characteristics induced by a randomly rough surface. A contact resonance frequency (CRF) can be obtained, and it is only positively correlated with the load, while the amplitude of CRF (CRFA) negatively correlates with the load and positively correlates with the velocity and surface profile height. Thereafter, a mixed-EHL model is employed to simulate the wear and lubrication progression of rolling-sliding contact. The surface roughness, contact load ratio (CLR), and contact area ratio (CAR) within this process are assigned specific physical interpretations and incorporated into the dynamic model. Given the nonlinear and coupled interactions of these three factors, the CRF and CRFA can distinguish the normal wear and severe wear stages. When the tribo-pair is in a normal wear stage, the CRF and CRFA show an increasing trend with the increase in surface roughness. Upon reaching a severe wear stage, the CRF gradually stabilises while the CRFA exhibits noticeable irregular fluctuations as the roughness increases. Finally, experiments are conducted to demonstrate the effectiveness of this method. Full article

Background/Objectives: The wellness profile of healthcare professionals is of crucial importance since it can affect the quality of healthcare services. This study created a comprehensive profile of health, functional capacity, physical fitness, and lifestyle behaviours in hospital healthcare professionals. Methods: A hundred female (age: 45.53 ± 2 yrs) professionals underwent assessments of their health (respiratory function/blood pressure/body circumference/body fat/body mass index/musculoskeletal pains), functional capacity (flexibility/balance), physical fitness (strength/aerobic capacity), and daily habits (smoking/alcohol/caffeinated beverages/screen time/physical activity). Results: According to data analysis (descriptive statistics, paired t-tests to analyze possible differences between the right and left sides), (a) 39% of the participants were overweight and 28% obese, (b) 40–44% of the participants showed higher values than normal in waist circumference and systolic blood pressure, and (c) 96% of the participants showed musculoskeletal pains. Functional capacity and physical fitness demonstrated significant differences in balance and flexibility (p < 0.05) between sides (right/left) and low levels of strength and dynamic balance-agility. Moreover, 67% of the sample did not participate in physical activities, while a significant percentage showed increased screen time on weekdays (44%) and weekends (61%). Finally, 36% of the sample smoked, 62% consumed alcohol, and 92% consumed caffeinated beverages (the majority were within permissible limits). Conclusions: In conclusion, this study contributes valuable insights into the wellness profile of healthcare professionals to ensure optimal care for this population. Full article