Examinando por Autor "Ao, Xiang"

Mostrando 1 - 3 de 3

All-Fabric Triboelectric Nanogenerator (AF-TENG) Smart Face Mask: Remote Long-Rate Breathing Monitoring and Apnea Alarm
(ACS, 2023-03-28) Vázquez-López, Antonio; Sánchez del Río Saez, José; de la Vega, Jimena; Ao, Xiang; Wang, De-Yi
Since the beginning of the COVID-19 pandemic, the use of face masks has become not only mandatory in several countries but also an acceptable approach for combating the pandemic. In the quest for designing an effective and useful face mask, triboelectric nanogenerators (TENGs) have been recently proposed. Novel functionalities are provided with the use of TENGs in face masks due to the induced triboelectrification generated by the exhaled and inhaled breath, allowing their use as an energy sensor. Nonetheless, within the face mask, the presence of nontextile plastics or other common triboelectric (TE) materials can be undesired. Herein, we propose the use of an all-fabric TENG (AF-TENG) with the use of high molecular weight polyethylene (UHMWPE) and cotton fabric as negative and positive triboelectric layers, respectively. With these materials, it is possible to detect the breathing of the patient, which in the case of not detecting a signal over a few minutes can trigger an alarm locally, providing valuable time. Also, in this article, we have sent breathing signals locally and remotely to distances up to 20 km via Wi-Fi and LoRa, the same as warning signals in the case of detecting anomalies. This work reveals the use of TENGs in smart face masks as an important tool to be used in difficult epidemiological periods to the general public, bringing much more comfort and relaxation to patients and elderly in today’s society, and based on pristine eco-friendly materials.
Eco-friendly functional cellulose paper as a fire alarming via wireless warning transmission for indoor fireproofing
(Elsevier, 2023-06-09) Li, Xiaolu; Sánchez del Río Saez, José; Vázquez-López, Antonio; Ao, Xiang; Sánchez Díaz, Raquel; Wang, De-Yi
Herein, a strategy for fabricating wallpaper-based smart fire-warning systems to monitor and mitigate indoor fires is proposed. The fire-warning system, based on eco-friendly cellulose paper (CP), is produced via a simple dip-coating technique and provides flexibility, rapid low-temperature warning, and novel local and remote wireless signal conversion capability. Specifically, this fire-warning system can balance flexibility and flame retardancy, reducing the negative impact on the mechanical properties after adding flame retardants. Furthermore, the proposed fire-warning system meets the critical requirement of a fast low-temperature warning, showing warning messages within 2 s under 250 ºC, decreasing the response temperature below the combustion temperature of common materials (＞300 ºC). Moreover, the luminosity and temperature data collected can be sent to local and remote computers by wireless conversion. This work gives insight into the new generation of low-temperature smart fire-warning systems, including the contribution of wireless warning signal transmission to achieve smart and efficient fire detection.
MXene multi-functionalization of polyrotaxane based PCMs and the applications in electronic devices thermal management
(Elsevier, 2024-10-01) Yin, Guangzhong; López, Alba Marta; Collado, Ignacio; Vázquez-López, Antonio; Ao, Xiang; Hobson, Jose; Prolongo, Silvia G.; Wang, De-Yi
The aim of this work was to improve the thermal conductivity and electromagnetic shielding of the leakage proof phase change materials (PCMs), in which a polyrotaxane (PLR) was used as a support material to encapsulate PEG 1k or PEG 6k and MXene as multi-functional filler. The PCMs can be processed conveniently by a hot press and the PEG 1k containing samples showed excellent flexibility. We conducted a systematic evaluation of the phase transition behavior of the material, thermal conductivity and electromagnetic shielding performance tests. Notably, the PCMs achieved a high enthalpy values (123.9–159.6 J/g). The PCMs exhibited an increase of 44.3 %, and 137.5 % in thermal conductivity values with higher MXene content (5 wt%) for PLR-PEG6k and PLR-PEG1k, respectively, and show high shape stability and no leakage during and after phase transition. The introduction of MXene can significantly improve the electromagnetic shielding performance of PCM composites. Typically, higher conductive samples (samples which contain high MXene contents) offer a higher EMI SE shielding, reaching a maximum of 4.67 dB at 5.6 GHz for PLR-1K-MX5. These improvements solve the main problems of organic PEG based PCMs, thus making PLR-PEG-MXene based PCMs good candidates for thermoregulators of both solid-state disks and smart phone. It is worth pointing out that the sample PLR-1k-MX5 can decrease 4.3 °C of the reference temperature during cellphone running. Moreover, the temperature of the protecting sheet in the simulated solid state disk with PCM was significantly lower (showing a decreasing of 7.9 °C) compared with the blank sample.