Search Results (1,086)

Endoreversible engine cycles are a cornerstone of finite-time thermodynamics. We show that endoreversible Stirling engines operating with a one-component plasma as a working medium run at maximal power output with the Curzon–Ahlborn efficiency. As a main result, we elucidate that this is actually a consequence of the fact that the caloric equation of state depends only linearly on temperature and only additively on volume. In particular, neither the exact form of the mechanical equation of state nor the full fundamental relation are required. Thus, our findings immediately generalize to a larger class of working plasmas, far beyond simple ideal gases. In addition, we show that for plasmas described by the photonic equation of state, the efficiency is significantly lower. This is in stark contrast to endoreversible Otto cycles, for which photonic engines have an efficiency larger than the Curzon–Ahlborn efficiency. Full article

As yet, no study has investigated the use of a research magnetic resonance imaging (MRI) scanner to support undergraduate medical radiation science (MRS) students in developing their MRI knowledge and practical skills (competences). The purpose of this study was to test an innovative program for a total of 10 s- and third-year students of a MRS course to enhance their MRI competences. The study involved an experimental, two-week MRI learning program which focused on practical MRI scanning of phantoms and healthy volunteers. Pre- and post-program questionnaires and tests were used to evaluate the competence development of these participants as well as the program’s educational quality. Descriptive statistics, along with Wilcoxon signed-rank and paired t-tests, were used for statistical analysis. The program improved the participants’ self-perceived and actual MRI competences significantly (from an average of 2.80 to 3.20 out of 5.00, p = 0.046; and from an average of 34.87% to 62.72%, Cohen’s d effect size: 2.53, p < 0.001, respectively). Furthermore, they rated all aspects of the program’s educational quality highly (mean: 3.90–4.80 out of 5.00) and indicated that the program was extremely valuable, very effective, and practical. Nonetheless, further evaluation should be conducted in a broader setting with a larger sample size to validate the findings of this feasibility study, given the study’s small sample size and participant selection bias. Full article

One of the main motivations of this paper is to construct generating functions for generalization of the Touchard polynomials (or generalization exponential functions) and certain special numbers. Many novel formulas and relations for these polynomials are found by using the Euler derivative operator and functional equations of these functions. Some novel relations among these polynomials, beta polynomials, Bernstein polynomials, related to Binomial distribution from discrete probability distribution classes, are given. Full article

This paper reports findings on the social patterning of dog bite injuries in Scotland and discusses their implications for prevention policies. Previous studies have shown evidence of social inequalities in dog bites in other countries, but this analysis provides new evidence about Scotland. Three sources of health record data are used (NHS 24 (telephone) records, accident and emergency department records, and hospital admissions records). The records span the period of 2007–2019 and combine information on 59,111 health records involving injuries caused by dogs (from 48,599 different individuals). The results are presented, summarising the volume of dog bite injuries across time periods by the age of respondents, the location of the incident, and the Scottish Index of Multiple Deprivation categorisation for their locality. The results suggest consistent patterns of social inequality in injuries caused by dogs. We argue that the most important finding concerns the higher risk for people from more deprived areas, and we discuss mechanisms that might lie behind the patterns and how policies might respond to them. Existing policies focus on the breed of dog and punitive strategies, but we argue that different approaches are more likely to be effective in addressing a socially stratified public health issue. Full article

This study aims to develop and validate a user experience scale to construct an Actual System Use model for online courses based on the Technology Acceptance Model, allowing for a comprehensive assessment of the multidimensional factors affecting Learning Outcomes and Actual System Use in the context of online courses. The scale includes six core dimensions: Interactive Experience, Content Quality, Learning Outcomes, Teaching Quality, Technical Support, and Learning Motivation. Through a literature review, pre-survey, exploratory factor analysis, and confirmatory factor analysis, the reliability and validity of the developed scale were verified. A second-order complex Structural Equation Model was used to measure users’ Actual System Use with respect to online courses. The results demonstrate that the Interactive Experience and Learning Motivation dimensions play crucial roles in enhancing learners’ engagement and learning satisfaction, while Perceived Usefulness and Perceived Ease of Use significantly influence system usage behaviors. This study provides a systematic theoretical basis and empirical data for the design of online courses, offering valuable insights for optimizing course design and enhancing user experiences. Full article

This review examines the application of the geophysical methods for Transportation Infrastructure Slope Monitoring (TISM). In contrast to existing works, which address geophysical methods for natural landslide monitoring, this study focuses on their application to infrastructure assets. It addresses the key aspects regarding the geophysical methods most employed, the subsurface properties revealed, and the design of monitoring systems, including sensor deployment. It evaluates the benefits and challenges associated with each geophysical approach, explores the potential for integrating geophysical techniques with other methods, and identifies the emerging technologies. Geophysical techniques such as Electrical Resistivity Tomography (ERT), Multichannel Analysis of Surface Waves (MASW), and Fiber Optic Cable (FOC) have proven effective in monitoring slope stability and detecting subsurface features, including soil moisture dynamics, slip surfaces, and material heterogeneity. Both temporary and permanent monitoring setups have been used, with increasing interest in real-time monitoring solutions. The integration of advanced technologies like Distributed Acoustic Sensing (DAS), UAV-mounted sensors, and artificial intelligence (AI) promises to enhance the resolution, accessibility, and predictive capabilities of slope monitoring systems. The review concludes with recommendations for future research, emphasizing the need for integrated monitoring frameworks that combine geophysical data with real-time analysis to improve the safety and efficiency of transportation infrastructure management. Full article

(1) Background: Many mental health conditions either start or become apparent in childhood or adolescence. This paper reports on aspects of a study which explored the perspectives of 12 teachers from independent secondary schools in Western Australia on how the mental health and wellbeing of students exhibiting symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD) can be fostered within classrooms. Specifically, the focus here was on mental health challenges faced by students with ADHD symptoms and the strategies teachers employ to support their mental wellbeing. (2) Methods: A qualitative approach was taken to the study’s design and the data analysis. Teachers responded to a survey with four open-ended questions, and then participated in individual, semi-structured interviews. (3) Results: The analysis led to the generation of four themes relating to students’ mental health challenges, as well as comprehensive strategies used by teachers to address these. (4) Conclusions: The findings indicated that adolescents with ADHD, regardless of a formal diagnosis, experience significant difficulties with their mental health and academic achievement as a result of their ADHD symptoms, but also that the participant teachers employed a wide range of strategies to assist these students, including those that target their specific mental health challenges and those that are holistic and support their wellbeing more generally. Full article

This study investigated the effects of three mulch types (straw, vermicompost and “plastic”) plus an untreated control, and three irrigation regimes (RFD: rainfed conditions; SIF: one supplemental irrigation at the flowering stage; SIVF: two supplemental irrigations at the vegetative and flowering stages) on the growth, seed yield, oil composition, and biochemical status of linseed (Linum usitatissimum L.). Linseed plants were best affected by SIVF and straw mulch in terms of seed yield (300 and 222.4 g m⁻², respectively), biomass yield (887.9 and 703 g m⁻², respectively), and concentration of oleic and linoleic acids. Under rainfed conditions, “plastic” mulch application increased stearic acid concentrations, while SIF increased palmitic acid concentrations. Rainfed conditions promoted the accumulation of proline (10.1 μmol g⁻¹ fresh weight), total phenols (6.68 mg g⁻¹ fresh weight), and DPPH radical scavenging capacity (56.5%). Under RFD, plants grown in straw-mulched soil showed the highest total phenol content and DPPH radical scavenging capacity, while control (unmulched) plants displayed the highest proline concentration at this irrigation regime. Enzyme activities, including catalase and superoxide dismutase, were enhanced under straw and “plastic” mulch compared to control plants under rainfed conditions. Our findings suggest that straw mulch represents an effective, sustainable strategy to successfully manage linseed crops, mitigating the adverse effects of water deficit stress on plant performance. Full article

The bending of topological interlocking (TI) plates under point loading is not smooth; it is accompanied by developing lines of localization commensurate with the symmetry of the interlocking assembly. Furthermore, the developed stage of deflection is characterized by post-peak softening. This paper proposes a new concept that explains these experimentally observed phenomena. A new model considers that due to the absence of bonding between the blocks, they assume independent rotational degrees of freedom; this is missed in the traditional modeling of TI structures. The bending resistance of TI beams relies on the elasticity of the peripheral constraint (frame or post-tensioning cables) resisting the additional loading caused by the relative rotation of blocks—a phenomenon called elbowing. This is independent of the particulars of the shape of interlocking blocks, which makes it possible to model the deflection of the TI beams as the deflection of fragmented beams consisting of parallelepiped blocks with restricted out-of-beam relative displacements. The model demonstrates that the bending of TI beams produces the experimentally observed point deflection, which is considerably different from that of conventional beams. This is a consequence of independent block rotation and elbowing. It is shown that the other consequence of block rotation with elbowing is the force–deflection relationship exhibiting a post-peak softening (apparent negative stiffness). Based on the point deflection model, it is demonstrated that oscillations of TI blocks involve a unidirectional damping with discontinuous velocity dependence. This paper develops a model of such damping. The results are important for designing flexible topological interlocking structures with energy absorption. Full article

The accurate and timely determination of crop leaf area indices (LAIs) assists in making agricultural decisions. The objective of this study was to estimate crop LAIs using C-band RADARSAT-2 synthetic aperture radar (SAR) datasets and a modified water cloud model (MWCM). The WCM was improved through two steps: (1) constructing a vegetation coverage ratio ($f_v$) using normalized difference vegetation indices calculated from Landsat-8 images and introducing it into the traditional WCM, and (2) incorporating field-collected crop height into the vegetation canopy described in the scattering model. The proposed MWCM parameters were calibrated using an iterative optimization algorithm named the Levenberg–Marquardt (LM) algorithm. The model’s performance before and after improvement was systematically calibrated and validated using field data collected from Yigen Farm (Hulunbuir City, Inner Mongolia Autonomous Region, China). The results show that the MWCM performed better than the original WCM in four polarization channels—HH, VV, HV, and VH—for both wheat and rape oilseed LAI inversion. HH polarization showed the best performance using both the MWCM and WCM for wheat, with R² values of 0.4626 and 0.3327, respectively; meanwhile, for oilseed rape, the R² values were 0.4912 and 0.3128, respectively. The RMSEs of the wheat inversion results were reduced from 1.5227 m²m⁻² to 1.4898 m²m⁻², and those for oilseed rape were reduced from 1.0411 m²m⁻² to 0.7968 m²m⁻². This study proved the feasibility and superiority of the MWCM, which provides new technical support for accurate crop growth monitoring. Full article

This study aimed to evaluate the apparent digestibility coefficients (ADCs) for nutrients and energy of seven conventional and alternative feed ingredients (poultry feather meal, fermented feather meal, mealworm meal, defatted black soldier fly, Chlorella, poultry by-product meal, and corn meal) when fed to Sobaity seabream (Sparidentex hasta), with the goal of identifying sustainable, digestible, and nutritionally viable ingredients for aquaculture feed formulations. A reference diet (RF) was formulated to meet the nutrient requirements of Sobaity seabream while test diets were prepared to contain 70% RF and 30% of the test ingredients. Sobaity seabream (200 ± 8.0 g) were fed the diets for seven days before fecal matter was collected by stripping. The whole length of the digestibility trial was 21 days. The ingredient apparent digestibility of dry matter (34.8–70.4%), crude protein (52.8–107.8%), crude lipid (67.7–112.9%), and energy (52.2–86.1%) were affected by test ingredients (p < 0.01). The dry matter digestibility of mealworm meal was the highest (70.4%) compared to other ingredients. Feather meal, Chlorella, and black soldier fly meal had significantly lower values of dry matter digestibility. Dry matter and crude protein were significantly more digestible in fermented feather meal than the feather meal without fermentation. The crude protein digestibility was significantly higher (107.8%) for mealworm meal. However, feather meal has shown a significantly lower value (52.8%) for crude protein digestibility compared to other ingredients. Energy digestibility showed a significant positive correlation with dry matter digestibility (r = 0.870). The energy digestibility of mealworm meal was significantly higher (86.1%, p < 0.05) than other ingredients. Feather meal had the lowest energy digestibility (52.2%) with no statistically significant difference from Chlorella, corn meal, and black soldier fly meal. This study indicates that mealworm meal is the most easily digestible protein source for Sobaity seabream and should be prioritized in their diets. Fermentation enhances the digestibility of feather meal and is recommended when using it. Ingredients with a lower digestibility, like feather meal, chlorella, and black soldier fly meal, should be used in moderation or undergo further processing to improve nutrient availability. Full article

A previous study determined criteria ensuring that a probability distribution supported in positive integers is the limiting conditional law of a subcritical Markov branching process. It is known that there is an close connection between the limiting conditional law and the stationary measure of the transition semigroup. This paper revisits that theme of by seeking tractable criteria ensuring that a sequence on positive integers is the stationary measure of a subcritical or critical Markov branching process. These criteria are illustrated with several examples. The subcritical case motivates consideration of the Sibuya distribution, leading to the demonstration that members of a certain family of complete Bernstein functions, in fact, are Thorin–Bernstein. The critical case involves deriving a notion of the limiting law of population size given that extinction occurs at a precise future time. Examples are given, and some show an interesting relation between stationary measures and Hausdorff moment sequences. Full article

In this paper, we present two symbolic methods, in particular, the method starting from the source identity, umbra identity, for constructing identities of s-Appell polynomials related to Stirling numbers and binomial coefficients. We discuss some properties of s-Appell polynomial sequences related to Riordan arrays, Sheffer matrices, and their q analogs. Full article

Under rainfed Mediterranean-style conditions, crop growth and yield are largely determined by the availability of water. We investigated the role of residue orientation (standing or horizontal) and quantity on temperature, soil water, and wheat growth in two experiments with annual (winter) cropping. In the first trial at Shenton Park, tall (0.3 m) standing residues combined with thick (4 t ha⁻¹) horizontal residues increased the soil water at sowing by more than 100 mm compared with the bare soil control, increasing the wheat yield by about 2 t ha⁻¹. The average soil water storage was linearly related to the total residue quantity (r² = 0.86). Both standing and horizontal residues reduced the daily soil temperature fluctuations, but increased the air temperature fluctuations. Tall-cut residues had higher maximum and lower minimum air temperatures 0.05 m above the ground than short-cut residues with more horizontal material. Under field conditions, more soil water was stored in the growing season with the residues cut relatively tall with less on the ground compared with an equivalent residue amount consisting of shorter residues with more on the ground, although the differences were not great. Tall stubble was also associated with greater green leaf area and PAR interception. At the Cunderdin trial, the residue was greater between the harvester wheel tracks than at the outer edge of the cutting front. Under the very dry seasonal conditions experienced during the trial, greater residue resulted in increased soil water storage, particularly in the top 0.5 m of soil (up to 29 mm), greater green leaf area index, and higher crop yields (up to 300 kg ha⁻¹) behind the harvester, associated with greater spike m⁻², greater spikelets spike⁻¹, and lower root:shoot ratio. These results demonstrate the importance of considering residue orientation to maximise crop water use efficiency and yield. Full article

Nowadays, as a result of the increasing awareness of European societies and new legal regulations, the role of renewable energy sources in individual heating is growing. One of the forms of renewable heat and electricity production is the use of biomass pellet burners coupled with Stirling engines. To ensure high system efficiency, the combustion process of this type of fuel requires an appropriate design of the burners, which can provide high-temperature flue gases. This requirement may be challenging, as the long operation of such a burner may cause the thermal degradation of its components, mainly the upper burner wall. The subject of this analysis was a burner with a nominal power of 10 kW. As the analysis tool, a previously validated CFD model was used. In this work, two ways of thermal degradation prevention are presented. The first one is geometry optimization via secondary air hole distribution. The results show that an appropriate geometrical design of the burner may be an efficient way of shifting the high-temperature zone to the burner axis, which may mitigate the thermal degradation risk. Secondly, the inlet air mass flow is changed to show its impact on the presence and location of the high-temperature zone. Both methods can be treated as interesting ways for solving the challenge of the long-term operation of high-temperature biomass burners by avoiding thermal degradation. Full article