Search Results (24,578)

Three-body recombination reactions, in which two particles form a bound state while a third one bounces off after the collision, play significant roles in many fields, such as cold and ultracold chemistry, astrochemistry, atmospheric physics, and plasma physics. In this work, the dynamics of the recombination reaction for the N₃ system over a wide temperature range (5000–20,000 K) are investigated in detail using the quasi-classical trajectory (QCT) method based on recently developed full-dimensional potential energy surfaces. The recombination products are N₂(X) + N(⁴S) in the 1⁴A″ state, N₂(A) + N(⁴S) in the 2⁴A″ state, and N₂(X) + N(²D) in both the 1²A″ and 2²A″ states. A three-body collision recombination model involving two sets of relative translational energies and collision parameters and a time-delay parameter is adopted in the QCT calculations. The recombination process occurs after forming an intermediate with a certain lifetime, which has a great influence on the recombination probability. Recombination processes occurring through a one-step three-body collision mechanism and two distinct two-step binary collision mechanisms are found in each state. And the two-step exchange mechanism is more dominant than the two-step transfer mechanism at higher temperatures. N₂(X) formed in all three related states is always the major recombination product in the temperature range from 5000 K to 20,000 K, with the relative abundance of N₂(A) increasing as temperature decreases. After hyperthermal collisions, the formed N₂(X/A) molecules are distributed in highly excited rotational and vibrational states, with internal energies mainly distributed near the dissociation threshold. Additionally, the rate coefficients for this three-body recombination reaction in each state are determined and exhibit a negative correlation with temperature. The dynamic insights presented in this work might be very useful to further simulate non-equilibrium dynamic processes in plasma physics involving N₃ systems. Full article

Background/Objectives: The present work proposes a mathematical model able to describe the dissolution of poly-disperse drug spherical particles in a solution (Dissolution Rate Test—DRT). DRT is a pivotal test performed in the pharmaceutical field to qualitatively assess drug bioavailability. Methods: The proposed mathematical model relies on the key hallmarks of DRT, such as particle size distribution, solubility, wettability, hydrodynamic conditions in the dissolving liquid of finite dimensions, and possible re-crystallization during the dissolution process. The spherical shape of the drug particles was the only cue simplification applied. Two model drugs were considered to check model robustness: theophylline (both soluble and wettable) and praziquantel (both poorly soluble and wettable). Results: The DRT data analysis within the proposed model allows us to understand that for theophylline, the main resistance to dissolution is due to the boundary layer surrounding drug particles, whereas wettability plays a negligible role. Conversely, the effect of low wettability cannot be neglected for praziquantel. These results are validated by the determination of drug wettability performed while measuring the solid–liquid contact angle on four liquids with decreasing polarities. Moreover, the percentage of drug polarity was determined. Conclusions: The proposed mathematical model confirms the importance of the different physical phenomena leading the dissolution of poly-disperse solid drug particles in a solution. Although a comprehensive mathematical model was proposed and applied, the DRT data of theophylline and praziquantel was successfully fitted by means of just two fitting parameters. Full article

As humans’ additional arms or legs, supernumerary robotic limbs (SRLs) have gained great application prospects in many fields. However, current SRLs lack both rigidity/flexibility adaptability and arm/leg function conversion. Inspired by the muscular hydrostat characteristics of octopus tentacles, fiber-reinforced actuators (FRAs) were employed to develop SRLs simultaneously realizing flexible operation and stable support. In this paper, an SRL with FRAs was designed and implemented. The analytic model of the FRA was established to formulate the movement trajectory and stiffness profile of the SRL. A hierarchical hidden Markov model (HHMM) was proposed to recognize the wearer’s motion intention and control the SRL to complete the specific working mode and motion type. Experiments were conducted to exhibit the feasibility and superiority of the proposed robot. Full article

This article introduces one of the forgotten figures of religious and literary studies: the Italian scholar, philosopher, metaphysician, poet and writer Silvano Panunzio (1918–2010). His contribution has so far been relegated to the margins of academic debate, and, currently, there are no academic studies on his work, in which mysticism plays a pivotal role. Panunzio believed that the transcendental and mystical dimension is fundamental for fully understanding the social, cultural, historical and political events of humanity. Another relevant aspect of his work is the importance he gave to literature and its relationship with mysticism, as in the case of Dante’s Divine Comedy or other European and Eastern writers and poets, such as Goethe, Shakespeare, Ibn Arabi and Dostoevsky. Significantly, Panunzio saved from oblivion the work of a forgotten man of letters of the nineteenth century, Gabriele Rossetti (1783–1854), who proposed the first symbolic and esoteric interpretation of Dante’s literary production and of European medieval love literature. Raising awareness of the intellectual amnesia around the figure of Silvano Panunzio may be a useful contribution to future research, both in the field of religious and literary studies. Full article

Along with the rapid economic development that rural Vietnam has experienced since the implementation of the Doi Moi policy, increasing attention is being paid to the widening income inequality among rural households. Although several studies have been conducted to understand the drivers of rural inequality, there is a lack of analysis that considers different household characteristics simultaneously and quantifies their contributions to inequality. Our study aims to fill this gap by applying the Fields’ regression-based decomposition method to household data collected from VARHS 2012 and VARHS 2016. The analysis results show that human capital, indicated by the quantity and quality of working members, and physical capital, indicated by household mobility and access to information, are the main contributors that explain this inequality. Additionally, the decreasing variation in specific characteristics, such as education level, is found to reduce their contribution to inequality over time, consequently preventing these factors from exacerbating overall inequality. Full article

With the advancing development of Advanced Air Mobility (AAM), there is a collaborative effort to increase safety in the airspace. AAM is an advancing field of aviation that aims to contribute to the safe transportation of goods and people using aerial vehicles. When aerial vehicles are operating in high-density locations such as urban areas, it can become crucial to incorporate collision avoidance systems. Currently, there are available pilot advisory systems such as Traffic Collision and Avoidance Systems (TCAS) providing assistance to manned aircraft, although there are currently no collision avoidance systems for autonomous flights. Standards Organizations such as the Institute of Electrical and Electronics Engineers (IEEE), Radio Technical Commission for Aeronautics (RTCA), and General Aviation Manufacturers Association (GAMA) are working to develop cooperative autonomous flights using UAS-to-UAS Communication in structured and unstructured airspaces. This paper presents a new approach for collision avoidance strategies within structured airspace known as “digital traffic lights”. The digital traffic lights are deployed over an area of land, controlling all UAVs that enter a potential collision zone and providing specific directions to mitigate a collision in the airspace. This strategy is proven through the results demonstrated through simulation in a Cesium Environment. With the deployment of the system, collision avoidance can be achieved for autonomous flights in all airspaces. Full article

Background/Objectives: Medical interpreters support communication between medical professionals and foreign patients. However, the communication skills required of medical interpreters in the field are currently unclear. The purpose of this study was to investigate what medical professionals and medical interpreters consider to be most important communication skills of medical interpreters, and whether there are differences in perceptions between medical professionals and medical interpreters. Methods: From December 2023 to February 2024, we interviewed 10 medical professionals and medical interpreters (five medical professionals and five medical interpreters) working throughout Japan and in the United States. The narratives collected in the interviews were analyzed and evaluated in a conceptual framework. Results: Healthcare professionals and medical interpreters exhibited differences in perceptions regarding the most important communication skills for medical interpreters. The narratives of medical professionals and medical interpreters regarding medical interpreters’ communication skills were divided into a 2 × 2 grid consisting of four quadrants with two axes (intervention and perspective). Regarding the communication skills of medical interpreters, medical professionals were primarily concerned with the transmission of medical information and felt that it was necessary for interpreters to understand medical professionals’ perspectives and what they wanted to say in order to convey it accurately. In contrast, medical interpreters emphasized the importance of empathy and communication skills for respecting the other person and understanding the other person’s opinion and perspective. Additionally, to understand the patient’s perspective, medical interpreters reported that it was important to understand the cultural background of the patient and to maintain good relationships with all of the people around the patient. Conclusions: We explored the communication skills of medical interpreters and the characteristics of the perceptions and narratives of medical professionals and medical interpreters. Concepts regarding the communication skills of medical interpreters were divided into two axes (intervention and perspective) and presented as a 2 × 2 grid with four quadrants. The results of our study suggested that medical interpreters should actively intervene in interpretation situations involving foreign patients. Full article

Smartphones are intricately connected to the modern society. The two widely used mobile phone operating systems, iOS and Android, profoundly affect the lives of millions of people. Android presently holds a market share of close to 71% among these two. As a result, if personal information is not securely protected, it is at tremendous risk. On the other hand, mobile malware has seen a year-on-year increase of more than 42% globally in 2022 mid-year. Any group of human professionals would have a very tough time detecting and removing all of this malware. For this reason, deep learning in particular has been used recently to overcome this problem. Deep learning models, however, were primarily created for picture analysis. Despite the fact that these models have shown promising findings in the field of vision, it has been challenging to fully comprehend what the characteristics recovered by deep learning models are in the area of malware. Furthermore, the actual potential of deep learning for malware analysis has not yet been fully realized due to the translation invariance trait of well-known models based on CNN. In this paper, we present ViTDroid, a novel model based on vision transformers for the deep learning-based analysis of opcode sequences of Android malware samples from large real-world datasets. We have been able to achieve a false positive rate of 0.0019 as compared to the previous best of 0.0021. However, this incremental improvement is not the major contribution of our work. Our model aims to make explainable predictions, i.e., it not only performs the classification of malware with high accuracy, but it also provides insights into the reasons for this classification. The model is able to pinpoint the malicious behavior-causing instructions in the malware samples. This means that our model can actually aid in the field of malware analysis itself by providing insights to human experts, thus leading to further improvements in this field. Full article

Imbalanced data situations exist in most fields of endeavor. The problem has been identified as a major bottleneck in machine learning/data mining and is becoming a serious issue of concern in food processing applications. Inappropriate analysis of agricultural and food processing data was identified as limiting the robustness of predictive models built from agri-food applications. As a result of rare cases occurring infrequently, classification rules that detect small groups are scarce, so samples belonging to small classes are largely misclassified. Most existing machine learning algorithms including the K-means, decision trees, and support vector machines (SVMs) are not optimal in handling imbalanced data. Consequently, models developed from the analysis of such data are very prone to rejection and non-adoptability in real industrial and commercial settings. This paper showcases the reality of the imbalanced data problem in agri-food applications and therefore proposes some state-of-the-art artificial intelligence algorithm approaches for handling the problem using methods including data resampling, one-class learning, ensemble methods, feature selection, and deep learning techniques. This paper further evaluates existing and newer metrics that are well suited for handling imbalanced data. Rightly analyzing imbalanced data from food processing application research works will improve the accuracy of results and model developments. This will consequently enhance the acceptability and adoptability of innovations/inventions. Full article

This paper presents a comprehensive study on the design and performance of a high-power amplifier (PA) covering a broad frequency band from 0.1 to 4.8 GHz. Leveraging a 10 W GaN device, the amplifier achieves output power levels surpassing 10 W across the entire frequency band. Furthermore, the power-added efficiency (PAE) of the amplifier ranges from 47% to 59%, indicating its energy-efficient operation. With consistent gain characteristics varying between 7 and 15 dB, the design ensures reliable signal amplification for diverse applications. Notably, the approach introduces a simplified output matching network based on an LC network, prioritizing practicality without sacrificing performance. Additionally, comprehensive guidance is provided on utilizing the Smith chart for streamlined amplifier design, enabling engineers with an accessible methodology. Through a meticulous analysis, this work contributes to advancing the field of high-power amplification, offering enhanced performance and usability for next-generation wireless communication systems. Full article

Oil is one of the main resources used by all countries in the world. The ever-growing demand for oil and oil products forces oil companies to increase production and refining. In order to increase net profit, oil producing companies are constantly upgrading equipment, improving oil production technologies, and preparing oil for further processing. When considering the elements of primary oil refining in difficult conditions, such as hard-to-reach or in remote locations, developers face strict limitations in energy resources and dimensions. Therefore, the use of traditional systems causes a number of difficulties, significantly reducing production efficiency. In this study, the authors solve the problem of improving the characteristics of the oil separation process. In their work, the authors analyzed the separation columns of primary oil distillation, identified the shortcomings of the technological process, and searched for technological solutions. Having identified the lack of technical solutions for monitoring the state of the temperature field of the separation column, the authors developed their own hardware–software complex for monitoring the separation column (RF patents No. 2020665473, No. 2021662752 were received). The complex was tested and successfully implemented into production. The study provides an assessment of the economic efficiency of implementation for a year and a forecast of the economic effect for 10 years. Full article

The role of veterinary doctors, particularly those dedicated to Zoological Medicine, is becoming increasingly relevant and essential within the One Health framework. Educational and employment opportunities in this field vary widely across Europe, prompting us to characterise the sector in Portugal and Spain. A survey was conducted, resulting in 169 valid responses from veterinarians. Respondents were characterised based on gender, age, work environment, the highest level of education, additional training, whether they attended zoological medicine classes at university and their perception of the adequacy of that training. Further factors included years of experience, the percentage of their work involving zoological medicine, sectors they work in, the types of animals they treat, their confidence in treating these animals, sources of information they use, and membership in relevant professional associations. Relationships between these variables were examined. The results describe Iberian professionals working with non-traditional pets, wildlife, and zoo animals. Notably, only half of these professionals had taken zoological medicine classes at university; among those, the majority felt they inadequately prepared them for their work. Given the findings, enhancing the training and resources available to these professionals is crucial to prepare them for their roles better. Full article

This paper presents a novel parallel manipulator capable of generating two translations (2T), inside a vertical plane, and two rotations (2R), about horizontal axes, which are required in aerospace, manufacturing and rehabilitation fields. These four degrees of freedom are reached by means of a unique RRU and three RSS kinematic chains connected to a rhomboid-shaped mobile platform. The kinematic analysis of the new manipulator is provided, which includes the resolution of the inverse position problem and the velocity equations relating to input and output variables. Additionally, a methodology is proposed for obtaining the workspace free of singularities, collisions and kinematic joint range limitation. This systematic methodology allows designers to identify the critical factors affecting the workspace and, thus, to rearrange the mechanical design accordingly for optimum path planning. We represent the workspace using its two-dimensional subspaces (i.e., translational and rotational workspace). The results are analyzed for different working modes of the manipulator to see its potential use in applications wherein 2T2R motion is necessary. Full article

As a propulsor with a good application prospect, the flapping foil has been a hot research topic in the past decade. Although the research results of flapping foils have been very abundant, the performance-influencing mechanism of flapping foils is still not perfect, and the research considering three-dimensional (3D) effects for engineering applications is still very limited. Based on the above considerations, a systematic and parametric analysis of a small aspect ratio flapping foil is conducted to correlate the influencing factors including angle of attack (AoA) characteristics and wake vortex on the propulsive efficiency. Three-dimensional numerical analyses of full-active and semi-active flapping foils are carried out in this paper, in which the former focuses on different heave amplitudes and pitch amplitudes, and the latter concentrates on different spring stiffnesses. The analysis covers the full range of advance coefficient, which starts around 0 and ends at a thrust drop of 0. Firstly, the influence of the maximum AoA (α_max) on the efficiency and thrust coefficient of these two kinds of flapping foils is analyzed. The results show that for the small aspect ratio flapping foil in this paper, regardless of the full-active or semi-active form, the peak efficiency as high as 75% for both generally appears around α_max = 0.2 rad, while the peak thrust coefficient of 0.5 occurs near α_max = 0.3 rad. Then, by analyzing the wake flow field, it is found that the lower efficiency of larger α_max working points is mainly due to the larger vortex dissipation loss, while the lower efficiency of smaller α_max working points is mainly due to the larger friction loss of the foil surface. Furthermore, the plumpness of different AoA curves is compared and analyzed. It was found that, unlike the results of full-active flapping foils, the shape of the AoA curve of semi-active flapping foils with different spring stiffnesses is similar, and the relationship with efficiency is not strictly corresponding. This study is expected to provide guidance on both academics and industries in relevant fields. Full article

Women’s participation and leadership in technology and entrepreneurship are crucial for advancing innovation and ensuring inclusive economic development. Despite progress in gender equality, women in tech face challenges like under-representation and systemic biases. This research delves into the multifaceted experiences of women in tech innovation and entrepreneurship, highlighting the barriers they face and the strategies they use to overcome them. This study used a qualitative, observational design with semi-structured interviews and thematic analysis to explore the experiences and perceptions of entrepreneurial women in the Science, Technology, Engineering, and Mathematics (STEM) field. It was possible to conclude that entrepreneurial women exhibit a strong sense of autonomy, competence, and leadership, enabling them to manage their ventures independently and effectively. Also, the success of entrepreneurial women is multifaceted, combining personal fulfilment, professional achievements, and financial stability, with positive feedback and recognition playing a key role. Building strong social and supportive relationships is vital for entrepreneurial women, providing a sense of belonging, community, and emotional support. In this context, to empower women in STEM and entrepreneurship, Higher Education Institutions (HEIs) should promote entrepreneurship as a career path, provide practical and value-based education, and foster a work environment of trust, communication, and continuous learning. Full article