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Regenerated fiber Bragg grating sensing system for ultrasonic detection in a 900 °C environment
摘要： Heat-resistant composites, such as ceramic matrix composites (CMCs) and heat-resistant carbon fiber reinforced plastics (CFRPs), are expected to be used for aircraft engine parts. The development of reliable heat-resistant composite materials requires the use of nondestructive test (NDT) techniques for evaluating the progression of damage during material testing at elevated temperatures. Furthermore, structural health monitoring (SHM) technologies that operate under harsh environments are expected to be realized for monitoring heat-resistant composite structures. To provide potential solutions for the establishment of such technologies, this research developed a heat-resistant ultrasonic sensor based on a regenerated fiber-optic Bragg grating (RFBG). First, we fabricated an RFBG by annealing a normal FBG sensor. Because the RFBG exhibits high heat resistance at temperatures of 1000 °C, the sensor achieved stable ultrasonic detection at an elevated temperature. In addition, we attempted to use a π-phase-shifted FBG (PSFBG) as the seed grating to construct an ultrasonic sensor with enhanced performance. As a result, the R(PS)FBG sensor possessed a very short effective gauge length and achieved a broad frequency response to ultrasonic waves with frequencies greater than 1.5 MHz. The broadband detectability enables the R(PS)FBG sensor to acquire an accurate response to ultrasonic waves. Hence, we believe the regenerated Bragg grating-based ultrasonic sensors can contribute to establishing an effective nondestructive evaluation method for composite materials, thereby enabling a structural health monitoring system for a composite-made structure operating under extreme high-temperature environments.
关键词： structural health monitoring (SHM),ultrasonic detection,nondestructive test (NDT),regenerated fiber-optic Bragg grating (RFBG),high-temperature environment,Heat-resistant composites
更新于2025-09-04 15:30:14
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[ACM Press the 3rd International Conference - Tetouan, Morocco (2018.10.10-2018.10.11)] Proceedings of the 3rd International Conference on Smart City Applications - SCA '18 - Usage of watermarking techniques in medical imaging
摘要： In this paper, we present the usage of watermarking techniques in the medical imaging, watermarking is considered a great solution to protect the personal data of patients during the medical images and telemedicine data exchange. This paper is devised in two parts. The first one is reserved for an overview on image watermarking with a presentation of the most important requirements of watermarking (robustness, imperceptibility and capacity). We offer also the general scheme of watermarking with the two essential phases and different types of attacks. Furthermore, we present a classification of watermarking techniques based on various parameters such as: insertion domain, human perception and detection methods, in the end of the section we display some metrics and benchmarks for analysis the performance of the watermarking technique. The second part is reserved for the usage of watermarking techniques in medical imaging especially for integrity verification, authentication and data hiding, we also discuss a literature review on watermarking techniques for medical image. In addition, we present the concept of telemedicine and telehealth fields and the importance of watermarking in the modern health care.
关键词： telemedicine,e-health,medical imaging,medical image watermarking (MIW),Watermarking
更新于2025-09-04 15:30:14
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[ASME ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - San Francisco, California, USA (Monday 27 August 2018)] ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - Feasibility of PCB-Integrated Vibration Sensors for Condition Monitoring of Electronic Systems
摘要： The increasing complexity of electronics in systems used in safety critical applications, such as for example self-driving vehicles requires new methods to assure the hardware reliability of the electronic assemblies. Prognostics and Health Management (PHM) that uses a combination of data-driven and Physics-of-Failure models is a promising approach to avoid unexpected failures in the field. However, to enable PHM based partly on Physics-of-Failure models, sensor data that measures the relevant environment loads to which the electronics is subjected during its mission life are required. In this work, the feasibility to manufacture and use integrated sensors in the inner layers of a printed circuit board (PCB) as mission load indicators measuring impacts and vibrations has been investigated. A four-layered PCB was designed in which piezoelectric sensors based on polyvinylidenefluoride-co-trifluoroethylene (PVDF-TrFE) were printed on one of the laminate layers before the lamination process. Manufacturing of the PCB was followed by the assembly of components consisting of BGAs and QFN packages in a standard production reflow soldering process. Tests to ensure that the functionality of the sensor material was unaffected by the soldering process were performed. Results showed a yield of approximately 30 % of the sensors after the reflow soldering process. The yield was also dependent on sensor placement and possibly shape. Optimization of the sensor design and placement is expected to bring the yield to 50 % or better. The sensors responded as expected to impact tests. Delamination areas were present in the test PCBs, which requires further investigation. The delamination does not seem to be due to the presence of embedded sensors alone but rather the result of a combination of several factors. The conclusion of this work is that it is feasible to embed piezoelectric sensors in the layers of a PCB.
关键词： PVDF-TrFE,piezoelectric sensors,Prognostics and Health Management (PHM),condition monitoring,electronic systems,PCB-integrated vibration sensors
更新于2025-09-04 15:30:14
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Nonlinearities Associated with Impaired Sensors in a Typical SHM Experimental Set-Up
摘要： Structural Health Monitoring (SHM) gives a diagnosis of a structure assessing the structural integrity and predicting the residual life through appropriate data processing and interpretation. A structure must remain in the design domain, although it can be subjected to normal aging due to usage, action of the environment, and accidental events. SHM involves the integration of electronic devices in the inspected structure that sometimes are Piezoelectric Transducers (PZT). These are lightweight and small and can be produced in different geometries. They are used both in guided wave-based and electromechanical impedance-based methods. The PZT bonding requires essential steps such as preparation of the surfaces, application of the adhesive, and assembly that make the bonding process not so easy to be realised. Furthermore, adhesives are susceptible to environmental degradation. Transducer debonding or non-uniform distributed glue underneath the sensor causes the reduction of the performance and can affect the reliability of the SHM system. In this paper, a sensor diagnostic method for the monitoring of the PZT operational status is proposed in order to detect bonding defect/damage between a PZT patch and a host structure. The authors propose a method based on the nonlinear behaviour of the contact PZT/structure that allows the identification of the damaged PZT and the geometrical characterization of the debonding. The feasibility of the diagnostic procedure is demonstrated by numerical studies and experiments, where disbonds were created by inhibiting the adhesive action on a part of the interface through Te?on ?lm. The proposed method can be used to evaluate the sensor functionality after an extreme loading event or over a long period of service time.
关键词： impaired sensor,Structural Health Monitoring,Time of Flight,subharmonics
更新于2025-09-04 15:30:14
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Solar powered oxygen systems in remote health centers in Papua New Guinea: a large scale implementation effectiveness trial
摘要： Background Pneumonia is the largest cause of child deaths in Papua New Guinea (PNG), and hypoxaemia is the major complication causing death in childhood pneumonia, and hypoxaemia is a major factor in deaths from many other common conditions, including bronchiolitis, asthma, sepsis, malaria, trauma, perinatal problems, and obstetric emergencies. A reliable source of oxygen therapy can reduce mortality from pneumonia by up to 35%. However, in low and middle income countries throughout the world, improved oxygen systems have not been implemented at large scale in remote, difficult to access health care settings, and oxygen is often unavailable at smaller rural hospitals or district health centers which serve as the first point of referral for childhood illnesses. These hospitals are hampered by lack of reliable power, staff training and other basic services. Methods We report the methodology of a large implementation effectiveness trial involving sustainable and renewable oxygen and power systems in 36 health facilities in remote rural areas of PNG. The methodology is a before–and after evaluation involving continuous quality improvement, and a health systems approach. We describe this model of implementation as the considerations and steps involved have wider implications in health systems in other countries. Results The implementation steps include: defining the criteria for where such an intervention is appropriate, assessment of power supplies and power requirements, the optimal design of a solar power system, specifications for oxygen concentrators and other oxygen equipment that will function in remote environments, installation logistics in remote settings, the role of oxygen analyzers in monitoring oxygen concentrator performance, the engineering capacity required to sustain a program at scale, clinical guidelines and training on oxygen equipment and the treatment of children with severe respiratory infection and other critical illnesses, program costs, and measurement of processes and outcomes to support continuous quality improvement. Conclusions This study will evaluate the feasibility and sustainability issues in improving oxygen systems and providing reliable power on a large scale in remote rural settings in PNG, and the impact of this on child mortality from pneumonia over 3 years post–intervention. Taking a continuous quality improvement approach can be transformational for remote health services.
关键词： Pneumonia,Papua New Guinea,oxygen therapy,hypoxaemia,solar power,remote health centers
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE Workshop on Augmented and Virtual Realities for Good (VAR4Good) - Reutlingen, Germany (2018.3.18-2018.3.18)] 2018 IEEE Workshop on Augmented and Virtual Realities for Good (VAR4Good) - Augmented Visual Instruction for Surgical Practice and Training
摘要： This paper presents two positions about the use of augmented reality (AR) in healthcare scenarios, informed by the authors’ experience as an interdisciplinary team of academics and medical practicioners who have been researching, implementing, and validating an AR surgical telementoring system. First, AR has the potential to greatly improve the areas of surgical telementoring and of medical training on patient simulators. In austere environments, surgical telementoring that connects surgeons with remote experts can be enhanced with the use of AR annotations visualized directly in the surgeon’s field of view. Patient simulators can gain additional value for medical training by overlaying the current and future steps of procedures as AR imagery onto a physical simulator. Second, AR annotations for telementoring and for simulator-based training can be delivered either by video see-through tablet displays or by AR head-mounted displays (HMDs). The paper discusses the two AR approaches by looking at accuracy, depth perception, visualization continuity, visualization latency, and user encumbrance. Specific advantages and disadvantages to each approach mean that the choice of one display method or another must be carefully tailored to the healthcare application in which it is being used.
关键词： Human-centered computing—Mixed / augmented reality,Applied computing—Health care information systems
更新于2025-09-04 15:30:14