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  1. A dual energy harvester based upon the magnetoelectric mechanism is reported. The harvester can generate ∼52.1 mW under simultaneously applied magnetic field and ultrasound in porcine tissue operating under safety limits.

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    Free, publicly-accessible full text available March 19, 2025
  2. Abstract

    The transition of autonomous vehicles into fleets requires an advanced control system design that relies on continuous feedback from the tires. Smart tires enable continuous monitoring of dynamic parameters by combining strain sensing with traditional tire functions. Here, we provide breakthrough in this direction by demonstrating tire-integrated system that combines direct mask-less 3D printed strain gauges, flexible piezoelectric energy harvester for powering the sensors and secure wireless data transfer electronics, and machine learning for predictive data analysis. Ink of graphene based material was designed to directly print strain sensor for measuring tire-road interactions under varying driving speeds, normal load, and tire pressure. A secure wireless data transfer hardware powered by a piezoelectric patch is implemented to demonstrate self-powered sensing and wireless communication capability. Combined, this study significantly advances the design and fabrication of cost-effective smart tires by demonstrating practical self-powered wireless strain sensing capability.

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  3. Abstract

    Energy harvesting from extremely low frequency magnetic fields using magneto‐mechano‐electric (MME) harvesters enables wireless power transfer for operating Internet of Things (IoT) devices. The MME harvesters are designed to resonate at a fixed frequency by absorbing AC magnetic fields through a composite cantilever comprising of piezoelectric and magnetostrictive materials, and a permanent magnetic tip mass. However, this harvester architecture limits power generation because volume of the magnetic end mass is closely coupled with the resonance frequency of the device structure. Here, a method is demonstrated for maintaining the resonance frequency of the MME harvesters under all operating conditions (e.g., 60 Hz, standard frequency of electricity in many countries) while simultaneously enhancing the output power generation. By distributing the magnetic mass over the beam, the output power of the harvester is significantly enhanced at a constant resonance frequency. The MME harvester with distributed forcing shows 280% improvement in the power generation compared with a traditional architecture. The generated power is shown to be sufficient to power eight different onboard sensors with wireless data transmission integrated on a drone. These results demonstrate the promise of MME energy harvesters for powering wireless communication and IoT sensors.

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  4. Abstract

    The rapid enhancement of the thermoelectric (TE) figure‐of‐merit (zT) in the past decade has opened opportunities for developing and transitioning solid state waste heat recovery systems. Here, a segmented TE device architecture is demonstrated in conjunction with heterogeneous material integration that results in high unicouple‐level conversion efficiency of 12% under a temperature difference of 584 K. This breakthrough is the result of success in fabricating bismuth telluride/half‐Heusler segmented TE unicouple modules using a “hot‐to‐cold” fabrication technique that provides significantly reduced electrical and thermal contact resistance. Extensive analytical and finite element modeling is conducted to provide an understanding of the nature of thermal transport and contributions arising from various thermal and physical parameters. Bismuth telluride/half‐Heusler based segmented thermoelectric generators (TEGs) can provide higher practical temperature difference with optimum averagezTacross the whole operating range. These results will have immediate impact on the design and development of TEGs and in the general design of devices based upon heterostructures that take advantage of gradients in the figure of merit.

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  5. Abstract

    Internet of Things (IoT) is driving the development of new generation of sensors, communication components, and power sources. Ideally, IoT sensors and communication components are expected to be powered by sustainable energy source freely available in the environment. Here, a breakthrough in this direction is provided by demonstrating high output power energy harvesting from very low amplitude stray magnetic fields, which exist everywhere, through magnetoelectric (ME) coupled magneto‐mechano‐electric (MME) energy conversion. ME coupled MME harvester comprised of multiple layers of amorphous magnetostrictive material, piezoelectric macrofiber composite, and magnetic tip mass, interacts with an external magnetic field to generate electrical energy. Comprehensive experimental investigation and a theoretical model reveal that both the magnetic torque generated through magnetic loading and amplification of magneto‐mechanical vibration by ME coupling contributes toward the generation of high electrical power from the stray magnetic field around power cables of common home appliances. The generated electrical power from the harvester is sufficient for operating microsensors (gyro, temperature, and humidity sensing) and wireless data transmission systems. These results will facilitate the deployment of IoT devices in emerging intelligent infrastructures.

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