Search Results (1,350)

Background and Objectives: Rumors, disinformation, and fake news are problems of contemporary society. We live in a world where the truth no longer holds much importance, and the line that divides the truth from lies, between real news and disinformation, becomes increasingly blurred and difficult to identify. The purpose of this study is to describe this concept, to draw attention to one of the “pandemics” of the 21st-century world, and to find methods by which we can defend ourselves against them. Materials and methods. A cross-sectional study was conducted based on a sample of 442 respondents. Results. For 77.8% of the people surveyed, the concept of “fake news” is important in Romania. Regarding trust in the mass media, a clear dominance (72.4%) was observed among participants who have little trust in the mass media. Although 98.2% of participants detect false information found on the internet, 78.5% are occasionally deceived by the information provided. Of the participants, 47.3% acknowledged their vulnerability to disinformation. The main source of disinformation is the internet, as 59% of the interviewed subjects believed. As the best measure against disinformation, the study group was divided almost equally according to the three possible answers, all of which were considered to be equally important: imposing legal restrictions and blocking the posting of certain news (35.4%), imposing stricter measures for authors (33.9%), and increasing vigilance among people (30.5%). Conclusions. According to the statistics based on the participants’ responses, the main purposes of disinformation are propaganda, manipulation, distracting attention from the truth, making money, and misleading the population. It can be observed that the main intention of disinformation, in the perception of the study participants, is manipulation. Full article

We propose a single-phase chiral elastic metamaterial capable of simultaneously exhibiting negative effective mass density and negative bulk modulus in the ultrasonic frequency range. The unit cell consists of a regular hexagonal frame connected to a central circular mass through six obliquely oriented, slender aluminum beams. The design avoids the manufacturing complexity of multi-phase systems by relying solely on geometric topology and chirality to induce dipolar and rotational resonances. Dispersion analysis and effective parameter retrieval confirm a double-negative frequency region from 30.9 kHz to 34 kHz. Finite element simulations further demonstrate negative refraction behavior when the metamaterial is immersed in water and subjected to 32 kHz and 32.7 kHz incident plane wave. Equifrequency curves (EFCs) analysis shows excellent agreement with simulated refraction angles, validating the material’s double-negative performance. This study provides a robust, manufacturable platform for elastic wave manipulation using a single-phase metallic metamaterial design. Full article

The microstructure and mechanical properties of welded joints of API 5L X-52 steel plates cladded with AISI 316L-Si austenitic stainless steel were evaluated. The gas metal arc welding process with pulsed arc (GMAW-P) and controlled arc oscillation were used to join the bimetallic plates. After the root welding pass, buttering with an ERNiCrMo-3 filler wire was performed and multi-pass welding followed using an ER70S-6 electrode. The results obtained by optical and scanning electron microscopy indicated that the shielding atmosphere, welding parameters, and electric arc oscillation enabled good arc stability and proper molten metal transfer from the filler wire to the sidewalls of the joint during welding. Vickers microhardness (HV) and tensile tests were performed for correlating microstructural and mechanical properties. The mixture of ERNiCrMo-3 and ER70S-6 filler materials presented fine interlocked grains with a honeycomb network shape of the Ni–Fe mixture with Ni-rich grain boundaries and a cellular-dendritic and equiaxed solidification. Variation of microhardness at the weld metal (WM) in the middle zone of the bimetallic welded joints (BWJ) is associated with the manipulation of the welding parameters, promoting precipitation of carbides in the austenitic matrix and formation of martensite during solidification of the weld pool and cooling of the WM. The BWJ exhibited a mechanical strength of 380 and 520 MPa for the yield stress and ultimate tensile strength, respectively. These values are close to those of the as-received API 5L X-52 steel. Full article

This research proposes optimizing the thermal pattern in the sintering bed by manipulating the air supply. The impact of the air supply on the distribution of heat in the upper and lower layers of the material bed is investigated based on a numerical simulation model. An optimized air supply scheme is proposed to enhance the thermal distribution of the sintering bed. The simulation results suggest that decreasing the air supply during sintering in the upper layer leads to an increase in bed temperature and an extension of the melting zone thickness from 5 mm to 16 mm. Similarly, reducing the air supply during sintering of the lower layer prevents over-melting of the sintering material by reducing heat accumulation. However, both decrease the speed of vertical sintering. To optimize the sintering process, it is suggested to decrease the air supply during the early and late stages and increase it during the middle stage. This optimized air supply leads to a uniform temperature distribution, with a 30 °C decrease in the gap between the highest temperatures. Additionally, the melting zone thickness in the early sintering stage increases from 0 mm to 14 mm, and the average vertical sintering speed remains comparable. Full article

Acoustic coupling agents serve as critical interfacial materials connecting piezoelectric transducers with microfluidic chips in acoustofluidic systems. Their performance directly impacts acoustic wave transmission efficiency, device reusability, and reliability in biomedical applications. Considering the rapidly growing body of research in the field of acoustic microfluidics, this review aims to serve as an all-in-one reference on the role of acoustic coupling agents and relevant considerations pertinent to acoustofluidic devices for anyone working in or seeking to enter the field of disposable acoustofluidic devices. To this end, this review seeks to summarize and categorize key aspects of acoustic couplants in the implementation of acoustofluidic devices by examining their underlying physical mechanisms, material classifications, and core applications of coupling agents in acoustofluidics. Gel-based coupling agents are particularly favored for their long-term stability, high coupling efficiency, and ease of preparation, making them integral to acoustic flow control applications. In practice, coupling agents facilitate microparticle trapping, droplet manipulation, and biosample sorting through acoustic impedance matching and wave mode conversion (e.g., Rayleigh-to-Lamb waves). Their thickness and acoustic properties (sound velocity, attenuation coefficient) further modulate sound field distribution to optimize acoustic radiation forces and thermal effects. However, challenges remain regarding stability (evaporation, thermal degradation) and chip compatibility. Further aspects of research into gel-based agents requiring attention include multilayer coupled designs, dynamic thickness control, and enhancing biocompatibility to advance acoustofluidic technologies in point-of-care diagnostics and high-throughput analysis. Full article

With the rapid advancement of high-precision optical systems, increasingly stringent demands are imposed on the surface figure accuracy of optical components. The magnitude of residual stress in multilayer films directly influences the post-coating surface figure stability of these components, making the control of multilayer film stress a critical factor in enhancing optical surface figure accuracy. In this study, which addresses the process constraints and substrate damage risks associated with conventional annealing-based stress compensation for large-aperture optical components, we introduce an active stress engineering strategy rooted in in situ deposition process optimization. By systematically tailoring film deposition parameters and adjusting the thickness modulation ratio of TiO₂ and SiO₂, we achieve dynamic compensation of residual stress in multilayer structures. This approach demonstrates broad applicability across diverse optical coatings, where it effectively mitigates stress-induced surface distortions. Unlike annealing methods, this intrinsic stress polarity manipulation strategy obviates the need for high-temperature post-processing, eliminating risks of material decomposition or substrate degradation. By enabling precise nanoscale stress regulation in large-aperture films through controlled process parameters, it provides essential technical support for manufacturing ultra-precision optical devices, such as next-generation laser systems and space-based stress wave detection instruments, where minimal stress-induced deformation is paramount to functional performance. Full article

Soft continuum robots are constructed from soft and compliant materials and can provide high flexibility and adaptability to various applications. They have theoretically infinite degrees of freedom (DOFs) and can generate highly nonlinear behaviors, which leads to challenges in accurately modeling and controlling their deformation, compliance, and behaviors. Inspired by animals, embodied intelligence utilizes physical bodies as an intelligent resource for information processing and task completion and offloads the computational cost of central control, which provides a unique approach to understanding and modeling soft robotics. In this study, we propose a theoretical framework to explain and guide distributed sensing enabled embodied intelligence for soft finger manipulation from a physics-based perspective. Specifically, we aim to provide a theoretical foundation to guide future sensor design and placement by addressing two key questions: (1) whether and why the state of a specific material point such as the tip trajectory of a soft finger can be predicted using distributed sensing, and, (2) how many sensors are sufficient for accurate prediction. These questions are critical for the design of soft and compliant robotic systems with embedded sensing for embodied intelligence. In addition to theoretical analysis, the study presents a feasible approach for real-time trajectory prediction through optimized sensor placement, with results validated through both simulation and experiment. The results showed that the tip trajectory of a soft finger can be predicted with a finite number of sensors with proper placement. While the proposed method is demonstrated in the context of soft finger manipulation, the framework is theoretically generalizable to other compliant soft robotic systems. Full article

A significant development in pedagogical strategies which make use of the principles of embodied cognition can be found within the implementation of Immersive Virtual Reality (IVR) into art and design education. This theoretical study investigates how IVR-mediated embodiment enhances spatial thinking and creative problem-solving in art and design education by examining the taxonomy of embodied learning and principles of embodied cognition. The pedagogical affordances and limitations of IVR for creative learning are analyzed through a combination of empirical research and case studies, such as the Tangible and Embodied Spatial Cognition (TASC) system and Tilt Brush studies. Through gesture, spatial navigation, and environmental manipulation, IVR provides numerous possibilities for externalizing creative ideation; however, its implementation requires negotiating contradictions between virtual and physical materiality. IVR-based educational technologies have the potential to revolutionize teaching and learning. The goal of this paper is to provide educators with a theoretically grounded framework for applying embodied practices in IVR-based learning environments, while also acknowledging the current limitations of this technology. Full article

The mechanics of an elastic sheet reinforced with fiber mesh is investigated when undergoing bilateral in-plane bending and stretching. The strain energy of FRC is formulated by accounting for the matrix strain energy contribution and the fiber network deformations of extension, flexure, and torsion, where the strain energy potential of the matrix material is characterized via the Mooney–Rivlin strain energy model and the fiber kinematics is computed via the first and second gradient of deformations. By applying the variational principle on the strain energy of FRC, the Euler–Lagrange equilibrium equations are derived and then solved numerically. The theoretical results highlight the matrix and meshwork deformations of FRC subjected to bilateral bending and stretching simultaneously, and it is found that the interaction between bilateral extension and bending manipulates the matrix and network deformation. It is theoretically observed that the transverse Lagrange strain peaks near the bilateral boundary while the longitudinal strain is intensified inside the FRC domain. The continuum model further demonstrates the bidirectional mesh network deformations in the case of plain woven, from which the extension and flexure kinematics of fiber units are illustrated to examine the effects of fiber unit deformations on the overall deformations of the fiber network. To reduce the observed matrix-network dislocation in the case of plain network reinforcement, the pantographic network reinforcement is investigated, suggesting that the bilateral stretch results in the reduced intersection angle at the mesh joints in the FRC domain. For validation of the continuum model, the obtained results are cross-examined with the existing experimental results depicting the failure mode of conventional fiber-reinforced composites to demonstrate the practical utility of the proposed model. Full article

This paper presents the design and implementation of an autonomous robotic facility for textile sorting and recycling, leveraging advanced computer vision and machine learning technologies. The system enables real-time textile classification, localization, and sorting on a dynamically moving conveyor belt. A custom-designed pneumatic gripper is developed for versatile textile handling, optimizing autonomous picking and placing operations. Additionally, digital simulation techniques are utilized to refine robotic motion and enhance overall system reliability before real-world deployment. The multi-threaded architecture facilitates the concurrent and efficient execution of textile classification, robotic manipulation, and conveyor belt operations. Key contributions include (a) dynamic and real-time textile detection and localization, (b) the development and integration of a specialized robotic gripper, (c) real-time autonomous robotic picking from a moving conveyor, and (d) scalability in sorting operations for recycling automation across various industry scales. The system progressively incorporates enhancements, such as queuing management for continuous operation and multi-thread optimization. Advanced material detection techniques are also integrated to ensure compliance with the stringent performance requirements of industrial recycling applications. Full article

The equipment has been developed and the process of granulation of liquid selenium into water has been implemented. The process of selenium granulation is implemented at a temperature of 225–250 °C through unheated sieves with a diameter of holes of 1–2 mm at a density of perforation from 279 to 417 holes/dm². The specific productivity reaches 180 kg/(dm² × h), which corresponds to industrial-scale production. Electron microscopy studies revealed the localization of impurity elements in both the raw and granulated selenium. The composition and concentration of elements in localized areas were found to be random. For example, one area contained (by mass %) C—7.64; S—6.04; As—4.85; and Pb—40.72. Another, located nearby, contained C—4.68; Te—45.42; and Pb—12.67. In granulated selenium there was a noted increase in the number of spherical or close to spherical in shape voids, on the boundaries of which impurity elements were concentrated. The change in chemical composition of granules in comparison with the initial selenium was not established. The use of a granulated element is accompanied by simplification of manipulations with dispersed material and improvement of dosing conditions in technological processes using selenium. Full article

Magnetic levitation enables the confinement and melting of conductive metals using alternating magnetic fields, eliminating the need for a crucible or other contact supports. This makes the technology particularly suitable for applications where container use is impractical, such as preventing contamination between the melt and the crucible, handling high-purity materials, or facilitating in-orbit operations. For a given coil design and load, selecting the appropriate feeding parameters, such as the current and frequency, is crucial to ensure the correct operation of the device. This study investigates the optimal current and frequency values required to levitate an aluminum billet using a proposed longitudinal electromagnetic levitator, which represents an initial prototype of a more complex system for automated material manipulation. The analysis was conducted through 2D and 3D finite element method (FEM) simulations, assessing the equilibrium position and stability with respect to translations and rotations under various operating conditions. The study identifies an operating configuration that ensures vertical stability while minimizing excessive heating, in order to obtain a sufficiently long confinement time before the melting point is reached. A fully coupled 2D thermal simulation was then performed to assess the billet’s heating rate under the selected operating conditions. Finally, an experiment was conducted on a prototype to confirm billet levitation. Full article

Bone repair and regeneration following an injury still present challenges worldwide. Three-dimensional (3D) scaffolds made from various materials are used for bone tissue engineering (BTE) applications. Polymers, minerals and nanotechnology are now being used in combination to achieve specific goals for BTE, including the delivery of antimicrobials through the scaffolds to prevent post-surgical infection. While several materials are utilised for BTE, natural polymers present a unique set of materials that can be manipulated to formulate scaffolds for BTE applications. They have been found to demonstrate higher biocompatibility, biodegradability and lower toxicity. Some even naturally mimic the bone microarchitecture, providing inherent structural support for BTE. Natural polymers may be simply classified as those from plant and animal sources. From both sources, there are different types of proteins, polysaccharides and other specialised materials that are already in use for research in BTE. Interestingly, these have the potential to revolutionise the field of BTE with a sustainable approach. In this review, we first discuss the different natural polymers used in BTE from plant sources, followed by animal sources. We then explore novel materials that are aimed at sustainable approaches, focusing on innovation from the last decade. In these sections, we outline studies of these materials with different types of bone cells, including bone marrow mesenchymal stromal cells (MSCs), which are the progenitors of bone. We finally outline the limitations, conclusions and future directions from our perspective in this dynamic field of polymers in BTE. With this review, we hope to bring together the updated existing knowledge and the potential future of innovation and sustainability in natural polymers for biomimetic BTE applications for fellow scientists, researchers and surgeons in the field. Full article

Conventional all-optical modulators based on surface plasmon polaritons (SPPs) primarily utilize the nonlinear effect of a given material for modulation. Their performance is heavily dependent on the optical properties of the dielectric materials used and requires high pumping power. However, manipulating SPPs by controlling electron concentrations offers a material-independent approach suitable for all-optical modulators. In this paper, we propose a hybrid gold–ITO–silver block structure integrated within a Mach–Zehnder interferometer configuration to address this problem. The gold–ITO interface effectively localizes propagating SPPs. The pump light excites localized surface plasmons (LSPs) in the silver block, generating surface electric fields that modulate the electron concentration in the adjacent ITO layer. The extinction ratio is 50.8 dB when the electron concentration changes by 3.3 × 10²⁰ cm⁻³, indicating that this structure is an all-optical modulator with a high extinction ratio. This approach shows significant promise for reducing pump power and enhancing the performance of all-optical modulators. Full article

Structural symmetry preservation and breaking play important roles in optical manipulation at subwavelength scales. By precisely engineering the symmetry of the nanostructures, metasurfaces can effectively realize various optical functions such as polarization control, wavefront shaping, and on-chip optical integration, with promising applications in information photonics, bio-detection, and flexible devices. In this article, we review the recent advances in chiral and achiral metasurfaces based on symmetry manipulation. We first introduce the fundamental principles of chiral and achiral metasurfaces, including methods for characterizing chirality and mechanisms for phase modulation. Then, we review the research on chiral metasurfaces based on material type and structural dimensions and related applications in high-sensitivity chiral sensing, reconfigurable chiral modulation, and polarization-selective imaging. We then describe the developments in the application of achiral metasurfaces, particularly in polarization-multiplexed holography, phase-gradient imaging, and polarization-insensitive metalenses. Finally, we provide an outlook on the future development of chiral and achiral metasurfaces. Full article