Solar cookers are an alternative to the traditional cooking systems; they are clean and sustainable; however, the practical use of solar cookers is still limited by the intermittency of the sun and the lack of sufficient amount of heat during the sunset. The lack of successful thermal energy storage (TES) implementation ends up in the lack of consistent cooking performance and lower reliability in domestic application. In dealing with this challenge, the current review critically reviews solar cookers that have sensible and latent heat storage materials to improve effectiveness, reliability, and off-sunshine cooking abilities. The aims of this review are to: (i) determine the performance of solar cookers that use sensible, latent and hybrid TES systems; (ii) analyse thermo-physical characteristics and applicability of widely used phase change material (PCM), e.g. acetanilide and stearic acid and binary salt mixtures; (iii) determine the effectiveness of sensible heat storage materials such as granite, sand and thermal oils; and (iv) determine critical advancements in technology, limitations and gaps in research associated with heat transfer enhancement, system integration and long-term stability. Research literature shows that the latent heat storage with the help of PCMs significantly increases the thermal retention that allows cooking several hours after dark and increases the efficiency of the entire cooker by about 20-40% in comparison with traditional solar cookers. Sensible storage of heat utilizes reliable short term heat availability of three to five hours, as compared to hybrid storage systems that combine high heat storage capabilities and predictable heat output. Overall, the combination of sensible and latent TES resources improves the work of the solar cookers and encourages the use of energy resources in the households in a more sustainable way. The research in the future ought to concentrate on high-end storage materials, cost-efficient designs, and scalable systems to enhance efficiency and acceptance by the users.
Delamination is an important failure mode of composite materials and can cause structural failure without visible signs. Early and reliable detection is crucial, especially in safety related sectors such as aerospace, automotive or wind energy. Fiber Bragg grating (FBG) sensors have gained widespread popularity for structural health monitoring (SHM), thanks to their high sensitivity, immunity to electromagnetic interference, compactness, and multiplexing ability. This paper reviews the use of FBG sensors for acoustic signal-based delamination detection. The paper categorizes sensor configurations (embedded, surface mounted, hybrid), methods for obtaining signals estimation and extracting features. Time Frequency analysis techniques, including Short Time Fourier Transform (STFT), wavelet transforms, and Fast Fourier Transfer (FFT) are discussed together with machine learning and deep leaning techniques such as support vector machines (SVM), Convolutional Neural Networks (CNNs), long short-term memory models. Their performance of detecting and categorizing delamination events is indeed critically scrutinized. Hybrid systems between FBG and acoustic emission (AE) or piezoelectric sensors are described as a result of their improved detectability. Recent advancements are also discussed including nano enhanced coatings that aid in increasing sensor sensitivity and environmental hardiness. Environmental effects, signal loss and sensor location problems and cost of the system are considered. The review wraps up with discussion on the significant limitations that need to be addressed and suggestions for future directions, such as adaptive signal processing, integration of AI and field ready interrogation units. The extensive evaluation presented here establishes the ground for further development of FBG based SHM methods into real time delamination inspection tools for composite structures.
Coastal zones in Southeast Asia face escalating threats from climate change, necessitating robust monitoring techniques for effective management; however, a fragmented understanding of the methodologies used over the past decade persists. This study addresses this gap by conducting a systematic literature review, guided by the PRISMA (Preferred Reporting Items for Systematic review and Meta analysis), to comprehensively catalogue and analyse the techniques and methodologies for mapping coastal edge and zone dynamics in Southeast Asia from 2014 to 2024. The review was driven by the central research question: “What are the most commonly used techniques and methodologies for mapping coastal edge in Southeast Asia over the past decade?” Following a rigorous screening and quality appraisal process of 437 identified records, 48 high-quality articles were synthesized. The findings reveal four dominant themes: (1) the evolution and synergistic use of data sources, primarily Landsat and Sentinel constellations; (2) prevalent techniques for shoreline extraction and change analysis, notably the Digital Shoreline Analysis System (DSAS); (3) the adoption of advanced methodologies, including machine learning and integrated modeling; and (4) a synthesis of integrated workflows and a distinct geographical research bias. The study’s significance lies in providing a consolidated methodological framework for researchers and a critical evidence base for policymakers, while its primary recommendation is the urgent need to address the identified geographical research gaps in under-studied Southeast Asian nations to foster equitable and informed coastal governance.
Long waiting times refer to the prolonged length of time patients spend waiting for medical treatment. This is due to a lack of human resources or equipments such as doctors, nurses or treatment rooms. This study investigates the optimization of resources allocation in private specialist centre to address long waiting times and enhance operational efficiency. A simulation model was developed by using Discrete Event Simulation (DES) approach to represent the actual patient flow in the centre and identify system bottlenecks that contributed to the prolonged waiting times. To determine the most effective resource configuration, the DES model was optimized using the Simulation-Optimization capabilities of OptQuest in Arena software. The optimization process focused on minimizing the Total Average Waiting Time (TAWT) while adhering to operational constraints such as limited staff and equipment. The results significantly improved the Total Average Waiting Time (TAWT) by 52.74%, reduction from 234.26 minutes to 110.71 minutes. This finding highlights the effectiveness of Simulation-Optimization approach in healthcare resource planning and offers valuable insights for optimizing operations in private specialist centres as well as reducing the congestion.
Space missions require reliable and safe physiological monitoring systems, as well as capable of continuous operation, as microgravity affects cardiovascular function and heart rhythm stability. This study develops and validates an intelligent in-ear photoplethysmography (PPG) system for continuous cardiac rhythm monitoring and real-time arrhythmia detection. A total of 2,926 PPG signal segments were collected, covering both normal and arrhythmic conditions. Signals were recorded at 75 Hz and upsampled to 256 Hz, then preprocessed using a 0.56 Hz Butterworth filter, artifact detection, and segmentation into 2,560 data points (≈10 s). A hybrid ResNet–LSTM–Attention model was developed to extract morphological and temporal features, while performance was evaluated using 5-fold crossvalidation. The results demonstrated consistent and robust performance with accuracy 0.7138 ± 0.1115, AUC 0.8078 ± 0.0492, and F1-Score 0.7198 ± 0.0788, confirming the model’s capability to detect cardiac rhythm abnormalities from in-ear PPG signals. These findings highlight the potential of this technology as a continuous cardiovascular monitoring platform, suitable for integration into wearable devices and mobile health applications, as well as for use in extreme environments such as space, where conventional electrocardiography is less practical.
