Search Results (312)

A monolayer metasurface-based Linear Polarizer and Quarter-Wave Plate (LP&QWP) is proposed for compact and precise polarization control in chip-scale atomic clocks (CSACs). Finite-difference time-domain simulations reveal that the designed metasurface efficiently converts linearly polarized light into right-handed circularly polarized light. Experimental characterization of devices fabricated on optical glass substrates confirms the polarization manipulation performance, achieving a polarization extinction ratio (PER) of 4.8 dB and a degree of polarization (DOP) of 74.2%, confirming its ability to effectively control the state of polarization. The short-term frequency stability of the developed CSAC prototype reaches 9.29 × 10⁻¹¹ at 1 s and 1.59 × 10⁻¹¹ at 10,000 s, demonstrating its potential for integration into miniature timing systems. The novelty of this work lies in the specific application to CSACs and the co-optimization with attenuation, as the metasurface simultaneously realizes polarization control and optical power balancing within a single functional layer. This study bridges metasurface photonics and atomic frequency standards, providing a functional route toward polarization control and frequency stability in miniaturized chip-scale atomic clocks. Full article

The living lab Enrekang, established in 2019 in South Sulawesi, Indonesia, was created to strengthen rural communication and support collaborative innovation across agriculture, livestock, environment, and extension services. Its flagship initiative, the Digital Farmer Field School (DFFS), was co-designed as a digital tool to improve farmers’ access to practical and locally adapted information. The early phase of collaboration generated strong momentum, culminating in a functional prototype tested with farmer groups by 2022. However, progress slowed soon after, revealing a gap between the initiative’s early promise and its subsequent stagnation. This qualitative case study, conducted between December 2024 and June 2025, draws on document reviews, focus group discussions, semi-structured interviews, and participant observations to analyze how the slowdown emerged and how it altered communication, coordination, and relational expectations among participating actors. Applying the governance-of-innovation lifecycle and a social capital lens, the study shows that political transitions, leadership turnover, staff rotation, and the absence of policy and budgetary anchoring disrupted coordination routines and reduced cross-sector interaction, even as motivation among farmers and frontline staff remained high. The case also highlights the novelty and complexity of the living lab approach, which introduced coordination demands and institutional unfamiliarity that local systems were not yet equipped to absorb. This study contributes to ongoing debates on collaborative innovation by illustrating the vulnerability of living labs when governance arrangements do not evolve alongside innovation milestones. Sustaining similar efforts requires formal anchoring, adaptive coordination, and mechanisms that protect collaboration across political and institutional transitions. Full article

This paper proposes a novel method for feeding a half-turn quadrifilar helix antenna (QHA) operating in backfire mode. A self-phasing and self-supporting antenna is obtained using a specific method demonstrated numerically. Four straight parallel wires, by which a couple of short-circuited stubs are realized and connected in series with helix loops, constitute both the mast of the QHA and the feeding network. A prototype operating at 1 GHz is designed, realized, and measured. The results show a good axial ratio (measured cross-polar gain is about 25 dB below the co-polar one at the boresight) and good impedance matching over an adequately large frequency band. Full article

This research aims to identify a suitable design solution that models the behavior of a human’s center of mass. This solution can be implemented in an exoskeleton structure that is especially designed for children who require walking assistance and rehabilitation. The primary problem posed by exoskeleton designs is representing the effect of ground–foot contact on exoskeleton behavior under kinematic and dynamic conditions. To mitigate this, our main research objective was to develop a mechanical system that demonstrates the human center of mass (CoM) behavior on an exoskeleton designed for children with Duchenne Muscular Dystrophy. The research focuses on modeling human CoM behavior under kinematic circumstances and transferring this into a mechanical system conceptual design. The obtained results validate the proposed mechanical system through a comparative analysis between numerical processing, virtual prototyping, and experimental specific methods and procedures. Full article

Dementia disrupts communication not only as a cognitive process but as a relational practice, leaving people living with dementia (PLwD) at risk of exclusion when language fragments. This study examines how communication closeness, the felt sense of being understood, emotionally attuned, and socially connected, might be supported through Research in and through Design (Ri&tD). Drawing on formative mixed-reality studies and a participatory co-design workshop with PLwD, caregivers, and stakeholders, we iteratively developed a series of playful artifacts culminating in Neighbourly, a tactile board game designed to support relational interaction through rule-based, multimodal play. Across this design genealogy, prototypes were treated as Living Counter-Maps: participatory mappings that made patterns of gesture, rhythm, shared attention, and material engagement visible and discussable. Through iterative interpretation and synthesis, the study identifies three guiding principles for designing for communication closeness: supporting co-regulation rather than correction, enabling multimodal reciprocity, and providing a shared material focus for joint agency. The paper consolidates these insights in the Living Counter-Maps Framework, which integrates counter-mapping and Ri&tD as a methodological approach for studying and designing relational communication in dementia care. Full article

Background/Objectives: This study examined how maker-based physical education (PE) lessons, co-designed within a Professional Learning Community (PLC), expanded student participation and supported teacher professional growth. Focus was placed on engaging sport-marginalized students, often excluded due to ability, motivation, or social background. Methods: This qualitative single-case study examined a PE-focused professional learning community (PLC) that collaboratively designed maker-based PE lesson prototypes and partially implemented them in regular PE classes. Data included PLC documents, lesson plans, classroom observations, student work, and semi-structured teacher interviews, and were analyzed using inductive category analysis. Results: Three lesson types emerged: (1) physical data measurement and analysis, (2) performance feedback, and (3) play- and game-based formats. These diversified participation by promoting student roles beyond performers, such as creators and analysts. Sport-marginalized students took on new roles as creators and analysts and, at the same time, showed increased engagement in physical activities and more active participation in lessons as performers. Teachers shifted from skill-focused instruction to reflective, practice-based teaching. The PLC enabled sustained innovation and collective growth. Conclusions: Maker-based PE offers a low-cost, adaptable model for inclusive curriculum reform that promotes creativity, wellbeing, and participation. Future studies should explore its long-term impact, broader implementation, and strategies to support ongoing PLC-based innovation. Full article

Layered transition-metal oxides are among the most promising sodium-ion battery cathodes owing to their high specific capacities and structurally tunable frameworks. However, the prototypical P2-Na_0.67Ni_0.33Mn_0.67O₂ (NM) undergoes an irreversible P2 → O2 phase transition at high voltages, accompanied by severe lattice strain and capacity fade, which hinders practical deployment. Here, we propose a cooperative regulation strategy that couples Zn/Al co-doping with Na enrichment, and successfully synthesize P2-Na_0.80Ni_0.14Zn_0.14Mn_0.58Al_0.14O₂ (NMZA-N14). The optimized NMZA-N14 delivers an initial discharge capacity of 125 mAh g⁻¹ at 0.1C and demonstrates exceptional cycling and rate performance, retaining 98.6% of its capacity after 100 cycles at 0.2C and 93.6% after 200 cycles at 1C. Kinetic analyses indicate a higher Na⁺ diffusion coefficient and a lower charge-transfer resistance in NMZA-N14, evidencing substantially accelerated ion transport. In situ X-ray diffraction further reveals a reversible P2 → OP4 phase transition in the high-voltage regime with a unit-cell volume change of only ~2.27%, thereby avoiding the irreversible structural degradation observed in NM. This synergistic modulation markedly enhances structural stability and electrochemical kinetics, providing a viable pathway for the rational design of high-performance sodium-ion battery cathodes. Full article

Background: Age-related hearing loss (ARHL) is associated with decreased communication, reduced social engagement, cognitive decline and an increased risk of dementia globally. Although increasing studies report the benefits of combing auditory and cognitive training for older adults with ARHL, more evidence is needed to examine its effects. Moreover, existing training programs have been developed with minimal end-user involvement leading to low adherence rates. This study aimed to investigate the role of co-design in the development of an auditory–cognitive training system for older adults with ARHL. Methods: A co-design methodology was employed. Digital recordings of the co-design workshops were transcribed verbatim. An established reflexive thematic analysis methodology was used. Results: Fifteen older adults with ARHL, referred to as “co-researchers”, participated in three co-design workshops until data saturation was achieved. Consultations were held with two key service providers. Three key themes emerged: (1) older adults with ARHL prefer a user-friendly auditory–cognitive training system; (2) clear, localized and colloquial instructions for the training tasks are necessary; and (3) diversified, tailor-made and dual-task training tasks, performed in an interactive and game-like mode, can motivate and sustain usage of the training system. As a result, a prototype of a web-based, gamified, and adaptive auditory–cognitive dual-task training system was co-designed. Conclusions: Our findings affirmed the importance of genuinely listening to the voices of end-users and creating a system that is responsive to their needs and preferences. Future study is recommended to examine the effects of this system on older adults with ARHL. Full article

Smart furniture represents a growing field that integrates Internet of Things (IoT), embedded systems and assistive technologies, yet lacks a comprehensive synthesis of its components and applications. This PRISMA-guided systematic review analysed 35 studies published between 2014 and 2024, sourced from PubMed, Web of Science and Scopus. The included studies presented prototypes of smart furniture that used IoT, sensors or automation. The focus was on extracting data related to technological configurations, functional uses, validation methods, maturity levels and commercialisation. Three technological pillars emerged, data collection (n = 31 studies), transmission/processing (n = 30), and actuation (n = 22), often combined into multifunctional systems (n = 14). Health monitoring was the dominant application (n = 15), followed by environmental control (n = 8) and assistive functions for older adults (n = 8). Validation methods varied; 37% relied solely on laboratory testing, while 20% only involved end-users. Only one solution surpassed Technology Readiness Level (TRL) 7 and is currently on the market. Current research remains pre-commercial, with gaps in AI integration, long-term validation, and participatory design. Smart furniture shows promise for healthcare and independent living, but requires standardised evaluation, ethical data practices, and co-creation to achieve market readiness. Full article

The rapid expansion of Low Earth Orbit (LEO) satellite constellations necessitates the development of multi-band antennas that are not only high-performing but also low-cost, lightweight, and highly reliable for mass production. This paper addresses this need by proposing a novel shared-aperture reflectarray antenna for simultaneous S-band and X-band operation. The design is based on a single-layer architecture that co-integrates two electromagnetically distinct resonant elements—a cross-dipole for the S-band and a diamond-ring slotted patch for the X-band—onto a single 1.52 mm thick Rogers RO3003 substrate. This approach achieves a high frequency ratio of 4:1 while ensuring independent phase control and high isolation for each band through an optimized geometry, circumventing the complexity and reliability issues of conventional multilayer systems. A prototype with dimensions of 260 × 364 mm² was fabricated and experimentally validated in an anechoic chamber. It achieved a measured peak gain of 7.99 dBi at 1.996 GHz for the S-band and 17.99 dBi at 7.94 GHz for the X-band, respectively. The results confirm the viability of the proposed design, demonstrating a structurally simple, easily manufacturable, and cost-effective alternative to complex multilayer systems, making it a promising candidate for next-generation LEO satellite communication platforms. Full article

In this paper, we present the design, prototyping, and working of a cost-effective, energy-efficient, and scalable air quality monitoring system (AQMS), enabled by a Low-power, long-Range Wide-Area Network (LoRaWAN), an Internet of Things (IoT) technology designed to provide connectivity for massive machine-type communication applications. The growing threat of air pollution necessitates outdoor and mobile environmental monitoring systems to provide real-time, location-specific data, which is unfortunately not possible using fixed monitoring devices. For our AQMS, we have developed two custom-built sensor nodes. The first node is equipped with a Nucleo-WL55JC1 microcontroller and sensors to measure temperature, humidity, and carbon dioxide (CO₂), while the other node is equipped with an Arduino MKR WAN 1310 controller with sensors to measure carbon monoxide (CO), ammonia (NH₃), and particulate matter (PM2.5 and PM10). These sensor nodes connect to a WisGate Edge LoRaWAN gateway, which aggregates and forwards the sensor data to The Things Network (TTN) for processing and cloud storage. The final visualization is handled via the Ubidots IoT platform, allowing for real-time visualization of environmental data. Besides environmental data, we were able to acquire a received signal strength indicator, signal-to-noise ratio, as well as a frame counter, which shows the number of packets received by the gateway. We performed laboratory testing, which confirmed reliable communication, with a packet delivery rate of 98% and a minimal average latency of 2.5 s. Both nodes operated efficiently on battery power, with the Nucleo-WL55JC1 consuming an average of 20 mA in active mode, while the Arduino MKR WAN 1310 operated at 15 mA. These values ensured extended operation for remote deployment. The system’s low power consumption and modular architecture make it viable for smart city applications and large-scale deployments in resource-constrained areas. Full article

This paper introduces innovative approaches to the design of railway point machines, with particular emphasis on the implementation of multi-component AlNiCoFe alloys, classified as semi-hard magnetic materials. A comprehensive review of existing mechanisms for mechanical force transmission—from the electric motor to the throwing bar—was conducted. The inherent limitations of conventional dry friction clutches, commonly used in current point machine designs, are critically analyzed. Furthermore, the feasibility of employing multi-component AlNiCoFe alloys as functional materials in hysteresis magnetic clutches is examined, with a view toward enhancing the reliability and performance of railway point actuation systems. A review of diagnostic methods for railway point machines was conducted to evaluate the potential application of a novel magnetic torque limiter as a means to eliminate maintenance activities typically required for systems utilizing dry friction clutches. Experimental research was performed on AlNiCoFe alloys employed as the hysteresis layer in the proposed torque limiter. Microstructural and compositional analyses were carried out using scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD) to determine the crystallographic structure, chemical composition, and selected physical properties of the tested materials. The hysteresis loops of the tested materials were measured using a Vibrating Sample Magnetometer (VSM) over a wide temperature range. A prototype magnetic clutch, functioning as a torque limiter in a railway point machine, was developed and presented. The operational characteristics—specifically the throwing force as a function of time—were recorded for a railway point machine equipped with an electromechanical module incorporating the new magnetic torque limiter. The advantages of the proposed solution in terms of force transmission and overall system performance in railway point machine design were analyzed and discussed. Full article

The increasing adoption of high-performance DC motor control in embedded systems has driven the development of cost-effective solutions that extend beyond traditional software-based optimization techniques. This work presents a refined hardware-centric approach implementing real-time particle swarm optimization (PSO) directly executed on STM32 microcontroller for DC motor speed control, departing from conventional simulation-based parameter-tuning methods. Novel hardware-optimized composition of an interval type-2 fuzzy logic controller (FLC) and a PID controller is developed, designed for resource-constrained embedded systems and accounting for processing delays, memory limitations, and real-time execution constraints typically overlooked in non-experimental studies. The hardware-in-the-loop implementation enables real-time parameter optimization while managing actual system uncertainties in controlling DC micro-motors. Comprehensive experimental validation against conventional PI, PID, and PIDF controllers, all optimized using the same embedded PSO methodology, reveals that the proposed FT2-PID controller achieves superior performance with 28.3% and 56.7% faster settling times compared to PIDF and PI controllers, respectively, with significantly lower overshoot at higher reference speeds. The proposed hardware-oriented methodology bridges the critical gap between theoretical controller design and practical embedded implementation, providing detailed analysis of hardware–software co-design trade-offs through experimental testing that uncovers constraints of the low-cost microcontroller platform. Full article

Manual pea shelling is a labor-intensive task facing small-scale farmers in rural areas, requiring substantial physical effort and limiting productivity. This study employed a Design Thinking methodology to co-design an affordable, automatic pea sheller addressing the specific needs of resource-constrained farmers. The methodology comprised five phases: empathizing with farmers through interviews, defining technical specifications from user requirements and benchmarking analysis, ideating preliminary concepts through collaborative brainstorming, prototyping using 3D-printed food-grade materials, and testing with end-users under real operating conditions. The developed sheller features counter-rotating rollers operating at optimized speed with dual compartments for grain and shell separation. Experimental validation demonstrated good extraction efficiency with minimal grain damage, while field testing confirmed substantial time reduction compared to manual shelling and strong user acceptance. The fully 3D-printable design enables affordable, customizable production suitable for small-scale operations, demonstrating how user-centered co-design can create accessible agricultural technology that addresses both technical performance and socioeconomic constraints in rural communities. Full article

Finite element analysis (FEA) is common in biomedical engineering for combining design and material development, with model validation crucial for accurate prediction of material behavior. Simplified geometries are commonly needed in stent development due to high effort in prototype manufacturing. This study outlines a methodology for FEA validation related to stent development-related FEA validation using injection-molded planar 2D substructures from a stent design with two types of polymers: poly(l-lactide) (PLLA) and poly(glycolide-co-trimethylene carbonate) (PGA-co-TMC). Specimens underwent quasi-static and cyclic testing, including loading, stress relaxation, unloading, and strain recovery. The material model coefficients for FEA were calibrated for three different constitutive models: linear elastic–plastic (LEP), Parallel Rheological Framework (PRF), and Three-Network (TN) model. The validation of planar stent segment expansion (PSSE) showed strong agreement with the experiments in deformation patterns, with varying force–displacement responses. The PRF and TN models provided better fits for behavioral predictions, with the PRF model being especially favorable for PLLA, while all models exhibited limitations for PGA-co-TMC. This study proposes a robust approach for the material modeling in stent development, enabling efficient material screening and stent design optimization through a simplified 2D validation setup. Material model accuracy depends strongly on calibration–load case congruence, while phenomenological approaches (PRF) show enhanced model robustness against load case variations compared to physically coupled models (TN). Full article