Inorganic CsPbIBr2 perovskites have recently attracted enormous attention as a viable alternative... more Inorganic CsPbIBr2 perovskites have recently attracted enormous attention as a viable alternative material for optoelectronic applications due to their higher efficiency, thermal stability, suitable bandgap, and proper optical absorption. However, the CsPbIBr2 perovskite films fabricated using a one-step deposition technique is usually comprised of small grain size with a large number of grain boundaries and compositional defects. In this work, silver iodide (AgI) will be incorporated as an additive into the CsPbIBr2 perovskite precursor solution to prepare the unique perovskite CsI(PbBr2)1-x(AgI)x. The AgI additive in the precursor solution works as a nucleation promoter which will help the perovskite to grow and merge into a continuous film with reduced defects. With detailed characterizations, we found that incorporating AgI additive resulted in a uniform perovskite film with fewer grain boundaries, increased grain size, crystallinity, optical absorption while decreasing carrier ...
The proprietary bio-inspired in-situ triboluminescent optical fiber (ITOF) sensor was developed b... more The proprietary bio-inspired in-situ triboluminescent optical fiber (ITOF) sensor was developed by researchers at the High-Performance Materials Institute. The sensor has capability for in-situ, distributed and real time damage monitoring in large civil and aerospace structures. Unlike other sensors, the ITOF sensor does not require external light source or power for sensing damage and transmitting the signal. The ITOF sensor consists of polymer optical fiber and triboluminescent (TL) composite coating of manganese-doped zinc sulfide (ZnS:Mn), the material with the highest TL emission capability among all inorganic crystals. The optical fiber is consistently coated with the triboluminescent composite by a continuous dip coating process. Over the years, researchers have utilized ITOF sensors for damage monitoring in composites and concrete structures. The sensor can successfully detect damage such as delamination, crack, adhesive bond failure, and barely visible impact damage (BVID) in composites. A new sensor, ITOFPress, consisting of ITOF sensor, is being developed to provide real-time quasi-distributed load information on wind turbine composites blades. These works utilized ITOF sensor of diameter ranges 1450 ~ 1600 μm. For the first time, a smaller diameter ITOF sensor of 570 μm was embedded into the carbon fiber composites and tested under flexural loading for damage monitoring. The results showed that small-sized ITOF sensors can detect shear failure of the flexural beams. The successful fabrication and integration of smaller ITOF sensors into the composites reduce the possibility of the sensor having a negative impact on the properties of the host material.
Composite materials have gained increased usage due to their unique characteristic of a high-stif... more Composite materials have gained increased usage due to their unique characteristic of a high-stiffness-to-weight ratio. High-performing composite materials are produced in the autoclave by applying elevated pressure and temperature. However, the process is characterized by numerous disadvantages, such as long cycle time, massive investment, costly tooling, and excessive energy consumption. As a result, composite manufacturers seek a cheap alternative to reduce cost and increase productivity. The out-of-autoclave (OoA) process manufactures composites by applying vacuum, pressure, and heat outside of the autoclave. This review discusses the common out-of-autoclave processes for various applications. The theoretical and practical merits and demerits are presented, and areas for future research are discussed.
A simple method for locating optimal positions for UV lamps used in the curing of curvilinear com... more A simple method for locating optimal positions for UV lamps used in the curing of curvilinear composite components manufactured with the Resin Infusion between Double Flexible Tooling (RIDFT) process is proposed. A multivariate optimization model, consisting of continuously differentiable and two-dimensional integral domain parts was developed. This model has UV lamps positions, dimensions of the manufactured composite component, and UV power source as the input parameters. The optimum positions of the UV lamps are the output. The two-dimensional integration yields the difference between the required intensity and actual intensity the composite component receives. A Gauss qaudrature numerical integration method was used to numerically evaluate the surface integral, and the Davidon-Fletcher-Powell (DFP) algorithm was used for predicting optimum positions for the lamps. Mechanical and rheological properties of the UV cured laminates were compared with catalytically cured laminates. UV...
Here we report a highly sensitive and robust flexible thin film pressure sensor realized through ... more Here we report a highly sensitive and robust flexible thin film pressure sensor realized through the novel combination of mechanoluminescent (ML) material with perovskite. This thin film sensor is constructed through a low-cost and simple manufacturing technique. In this work, we adopted a lateral type design of a thin pressure sensor primarily consisting (i) a sensing layer of copper-doped zinc sulfide (ZnS:Cu)/polydimethylsiloxane (PDMS) composite and (ii) a light absorbing layer of perovskite. Atop the perovskite layer lies a thin Au layer acting as the electrodes. ZnS:Cu is one of the highest intensity light emitting material among all inorganic ML crystals. The ML intensity increases with the increase of applied pressure without requiring any irradiation for ML recovery, which indicates that the self-recovery of the ML in crystals takes place by trapping of drifting charge carriers in the presence of a piezoelectric field. As such, this crystal can be suitable for durable senso...
1.0 Introduction Over the past five decades, the utilization of advanced composites has shown inc... more 1.0 Introduction Over the past five decades, the utilization of advanced composites has shown increasing promise with their well documented advantages of high stiffness to weight rations, corrosion resistance, and functional integration. As such, the market share of structural composites has continued to experience exponential growth. Traditional fiber reinforced composites (FRCs) have matured with respect to their material properties. For instance, their in-plane, fiber-dominant properties make them highly desirable compared to metals, but their throughthickness or z-axis properties are matrix-dominant and, thus, have limited their use. [1-2].
Inorganic cesium lead halide CsPbIxBr3-x (x=0, 1, 2, 3) perovskites have recently gained consider... more Inorganic cesium lead halide CsPbIxBr3-x (x=0, 1, 2, 3) perovskites have recently gained considerable attention as semiconductor materials for the fabrication of photodetectors due to their high th...
Recent developments in sensing technologies have triggered a lot of research interest in explorin... more Recent developments in sensing technologies have triggered a lot of research interest in exploring novel self-powered, inexpensive, compact and flexible pressure sensors with the potential for structural health monitoring (SHM) applications. Herein, we assessed the performance of an embedded mechanoluminescent (ML) and perovskite pressure sensor that integrates the physical principles of mechanoluminescence and perovskite materials. For a continuous in-situ SHM, it is crucial to evaluate the capabilities of the sensing device when embedded into a composite structure. An experimental study of how the sensor is affected by the embedment process into a glass fiber-reinforced composite has been conducted. A series of devices with and without ML were embedded within a composite laminate, and the signal responses were collected under different conditions. We also demonstrated a successful encapsulation process in order for the device to withstand the composite manufacturing conditions. Th...
Inorganic CsPbIBr2 perovskites have recently attracted enormous attention as a viable alternative... more Inorganic CsPbIBr2 perovskites have recently attracted enormous attention as a viable alternative material for optoelectronic applications due to their higher efficiency, thermal stability, suitable bandgap, and proper optical absorption. However, the CsPbIBr2 perovskite films fabricated using a one-step deposition technique is usually comprised of small grain size with a large number of grain boundaries and compositional defects. In this work, silver iodide (AgI) will be incorporated as an additive into the CsPbIBr2 perovskite precursor solution to prepare the unique perovskite CsI(PbBr2)1-x(AgI)x. The AgI additive in the precursor solution works as a nucleation promoter which will help the perovskite to grow and merge into a continuous film with reduced defects. With detailed characterizations, we found that incorporating AgI additive resulted in a uniform perovskite film with fewer grain boundaries, increased grain size, crystallinity, optical absorption while decreasing carrier ...
The proprietary bio-inspired in-situ triboluminescent optical fiber (ITOF) sensor was developed b... more The proprietary bio-inspired in-situ triboluminescent optical fiber (ITOF) sensor was developed by researchers at the High-Performance Materials Institute. The sensor has capability for in-situ, distributed and real time damage monitoring in large civil and aerospace structures. Unlike other sensors, the ITOF sensor does not require external light source or power for sensing damage and transmitting the signal. The ITOF sensor consists of polymer optical fiber and triboluminescent (TL) composite coating of manganese-doped zinc sulfide (ZnS:Mn), the material with the highest TL emission capability among all inorganic crystals. The optical fiber is consistently coated with the triboluminescent composite by a continuous dip coating process. Over the years, researchers have utilized ITOF sensors for damage monitoring in composites and concrete structures. The sensor can successfully detect damage such as delamination, crack, adhesive bond failure, and barely visible impact damage (BVID) in composites. A new sensor, ITOFPress, consisting of ITOF sensor, is being developed to provide real-time quasi-distributed load information on wind turbine composites blades. These works utilized ITOF sensor of diameter ranges 1450 ~ 1600 μm. For the first time, a smaller diameter ITOF sensor of 570 μm was embedded into the carbon fiber composites and tested under flexural loading for damage monitoring. The results showed that small-sized ITOF sensors can detect shear failure of the flexural beams. The successful fabrication and integration of smaller ITOF sensors into the composites reduce the possibility of the sensor having a negative impact on the properties of the host material.
Composite materials have gained increased usage due to their unique characteristic of a high-stif... more Composite materials have gained increased usage due to their unique characteristic of a high-stiffness-to-weight ratio. High-performing composite materials are produced in the autoclave by applying elevated pressure and temperature. However, the process is characterized by numerous disadvantages, such as long cycle time, massive investment, costly tooling, and excessive energy consumption. As a result, composite manufacturers seek a cheap alternative to reduce cost and increase productivity. The out-of-autoclave (OoA) process manufactures composites by applying vacuum, pressure, and heat outside of the autoclave. This review discusses the common out-of-autoclave processes for various applications. The theoretical and practical merits and demerits are presented, and areas for future research are discussed.
A simple method for locating optimal positions for UV lamps used in the curing of curvilinear com... more A simple method for locating optimal positions for UV lamps used in the curing of curvilinear composite components manufactured with the Resin Infusion between Double Flexible Tooling (RIDFT) process is proposed. A multivariate optimization model, consisting of continuously differentiable and two-dimensional integral domain parts was developed. This model has UV lamps positions, dimensions of the manufactured composite component, and UV power source as the input parameters. The optimum positions of the UV lamps are the output. The two-dimensional integration yields the difference between the required intensity and actual intensity the composite component receives. A Gauss qaudrature numerical integration method was used to numerically evaluate the surface integral, and the Davidon-Fletcher-Powell (DFP) algorithm was used for predicting optimum positions for the lamps. Mechanical and rheological properties of the UV cured laminates were compared with catalytically cured laminates. UV...
Here we report a highly sensitive and robust flexible thin film pressure sensor realized through ... more Here we report a highly sensitive and robust flexible thin film pressure sensor realized through the novel combination of mechanoluminescent (ML) material with perovskite. This thin film sensor is constructed through a low-cost and simple manufacturing technique. In this work, we adopted a lateral type design of a thin pressure sensor primarily consisting (i) a sensing layer of copper-doped zinc sulfide (ZnS:Cu)/polydimethylsiloxane (PDMS) composite and (ii) a light absorbing layer of perovskite. Atop the perovskite layer lies a thin Au layer acting as the electrodes. ZnS:Cu is one of the highest intensity light emitting material among all inorganic ML crystals. The ML intensity increases with the increase of applied pressure without requiring any irradiation for ML recovery, which indicates that the self-recovery of the ML in crystals takes place by trapping of drifting charge carriers in the presence of a piezoelectric field. As such, this crystal can be suitable for durable senso...
1.0 Introduction Over the past five decades, the utilization of advanced composites has shown inc... more 1.0 Introduction Over the past five decades, the utilization of advanced composites has shown increasing promise with their well documented advantages of high stiffness to weight rations, corrosion resistance, and functional integration. As such, the market share of structural composites has continued to experience exponential growth. Traditional fiber reinforced composites (FRCs) have matured with respect to their material properties. For instance, their in-plane, fiber-dominant properties make them highly desirable compared to metals, but their throughthickness or z-axis properties are matrix-dominant and, thus, have limited their use. [1-2].
Inorganic cesium lead halide CsPbIxBr3-x (x=0, 1, 2, 3) perovskites have recently gained consider... more Inorganic cesium lead halide CsPbIxBr3-x (x=0, 1, 2, 3) perovskites have recently gained considerable attention as semiconductor materials for the fabrication of photodetectors due to their high th...
Recent developments in sensing technologies have triggered a lot of research interest in explorin... more Recent developments in sensing technologies have triggered a lot of research interest in exploring novel self-powered, inexpensive, compact and flexible pressure sensors with the potential for structural health monitoring (SHM) applications. Herein, we assessed the performance of an embedded mechanoluminescent (ML) and perovskite pressure sensor that integrates the physical principles of mechanoluminescence and perovskite materials. For a continuous in-situ SHM, it is crucial to evaluate the capabilities of the sensing device when embedded into a composite structure. An experimental study of how the sensor is affected by the embedment process into a glass fiber-reinforced composite has been conducted. A series of devices with and without ML were embedded within a composite laminate, and the signal responses were collected under different conditions. We also demonstrated a successful encapsulation process in order for the device to withstand the composite manufacturing conditions. Th...
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