Graphene/SiC-coated textiles with excellent electromagnetic interference shielding,Joule heating,high-temperature resistance,and pressure-sensing performances

Multifunctional,wearable,and durable textiles integrated with smart electronics have attracted tremendous attention.However,it remains a great challenge to balance new functionalities with high-temperature stability.Herein,textile-based pressure sensors with excellent electromagnetic interference(EMI)shielding,Joule heating,and high-temperature resistance were fabricated by constructing graphene/SiC(G/SiC)heterostructures on carbon cloth via laser chemical vapor deposition(LCVD).The resultant textiles exhibited excellent EMI efficiency of 74.2 dB with a thickness of 0.45 mm,Joule heating performance within a low working voltage(V)range of 1-3 V,and fast response time within 20 s.These properties arose from multiple reflections,interfacial polarization,and high conductivity due to the numerous amounts of nanoscale G/SiC heterostructures.More importantly,G/SiC/carbon fibers(CFs)demonstrated well high-temperature resistance with a heat resistance index(THri)of 380.2 C owing to the protection of a coating layer on the CFs upon oxidation.Meanwhile,the G/SiC/CFs presented good pressure-sensing performance with high sensitivity(S)of 52.93 kPal,fast response time of 85 ms,and a wide pressure range of up to 186 kPa.These features imply the potential of the G/SiC/CFs as efficient EMI shielding,electrical heater,and piezoresistive sensor textiles.

Dual emission of singlet and triplet states boost the sensitivity of pressure-sensing

Pressure-related sensing materials in mechanochromic luminescent materials have received wide attention.However,at present,most piezochromic luminescence(PCL)materials have problems such as aggregation-caused quenching(ACQ)effect due to the presence of powder form,complicated preparation methods and fluorescence quenching effect under high pressure.To solve these problems,we employ three components containing carbon dots(CDs),layered double hydroxides(LDHs)and polyvinyl alcohol(PVA)to construct the CDs-LDHs/PVA film.The LDHs can provide a rigid environment for CDs and improve the luminescent efficiency of CDs.The film shows high sensitivity,stability and reversibility.Moreover,the compressed film can recover to its original state by heating.Therefore,the PCL film with dual emission(fluorescence and phosphorescence)characteristic is constructed,which boosts the sensitivity of pressure-sensing.

The Third-Order Viscoelastic Acoustic Model Enables an Ice-Detection System for a Smart Deicing of Wind-Turbine Blade Shells

The present work is based on the third-order partial differential equation (PDE) of acoustics of viscoelastic solids for the quasi-equilibrium (QE) component of the average normal stress. This PDE includes the stress-relaxation time (SRT) for the material and is applicable at any value of the SRT. The notion of a smart deicing system (SDS) for blade shells (BSs) of a wind turbine is specified. The work considers the stress in a BS as the one caused by the operational load on the BS. The work develops key design issues of a prospective ice-detection system (IDS) able to supply an array of the heating elements of an SDS with the element-individual spatiotemporal data and procedures for identification of the material parameters of atmospheric-ice (AI) layer accreted on the outer surfaces of the BSs. Both the SDS and IDS flexibly allow for complex, curvilinear and space-time-varying shapes of BSs. The proposed IDS presumes monitoring of the QE components of the normal stresses in BSs. The IDS is supposed to include an array of pressure-sensing resistors, also known as force-sensing resistors (FSRs), and communication hardware, as well as the parameter-identification software package (PISP), which provides the identification on the basis of the aforementioned PDE and the data measured by the FSRs. The IDS does not have hardware components located outside the outer surfaces of, or implanted in, BSs. The FSR array and communication hardware are reliable, and both cost- and energy-efficient. The present work extends methods of structural-health/operational-load monitoring (SH/OL-M) with measurements of the operational-load-caused stress in closed solid shells and, if the prospective PISP is used, endows the methods with identification of material parameters of the shells. The identification algorithms that can underlie the PISP are computationally efficient and suitable for implementation in the real-time mode. The identification model and algorithms can deal with not only the single-layer systems such as the BS layer without the AI layer or two-layer systems but also multi-layer systems. The outcomes can be applied to not only BSs of wind turbines but also non-QE closed single- or multi-layer deformable solid shells of various engineering systems (e.g., the shells of driver or passenger compartments of ships, cars, busses, airplanes, and other vehicles). The proposed monitoring of the normal-stress QE component in the mentioned shells extends the methods of SH/OL-M. The topic for the nearest research is a better adjustment of the settings for the FSR-based measurement of the mentioned components and a calibration of the parameter-identification model and algorithms, as well as the resulting improvement of the PISP.