Browsing by Author "Shveda, Rachel A."

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    A predictive model of the temperature-dependent inactivation of coronaviruses
    (AIP, 2020) Yap, Te Faye; Liu, Zhen; Shveda, Rachel A.; Preston, Daniel J.
    The COVID-19 pandemic has stressed healthcare systems and supply lines, forcing medical doctors to risk infection by decontaminating and reusing single-use personal protective equipment. The uncertain future of the pandemic is compounded by limited data on the ability of the responsible virus, SARS-CoV-2, to survive across various climates, preventing epidemiologists from accurately modeling its spread. However, a detailed thermodynamic analysis of experimental data on the inactivation of SARS-CoV-2 and related coronaviruses can enable a fundamental understanding of their thermal degradation that will help model the COVID-19 pandemic and mitigate future outbreaks. This work introduces a thermodynamic model that synthesizes existing data into an analytical framework built on first principles, including the rate law for a first-order reaction and the Arrhenius equation, to accurately predict the temperature-dependent inactivation of coronaviruses. The model provides much-needed thermal decontamination guidelines for personal protective equipment, including masks. For example, at 70 °C, a 3-log (99.9%) reduction in virus concentration can be achieved, on average, in 3 min (under the same conditions, a more conservative decontamination time of 39 min represents the upper limit of a 95% interval) and can be performed in most home ovens without reducing the efficacy of typical N95 masks as shown in recent experimental reports. This model will also allow for epidemiologists to incorporate the lifetime of SARS-CoV-2 as a continuous function of environmental temperature into models forecasting the spread of the pandemic across different climates and seasons.
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    A Soft Textile-Based System to Harvest Walking Energy for Rehabilitative and Assistive Devices
    (2021-04-28) Shveda, Rachel A.; Preston, Daniel J.
    Wearable assistive, rehabilitative, and augmentative devices require bulky and heavy power supplies, often making these tools more of a burden than an asset. This work demonstrates a soft, low-profile, and comfortable textile-based energy harvesting system. Pneumatic energy is harvested with a textile device integrated into a shoe insole, and pneumatic energy is stored in a flexible textile wearable, enabling users to produce and store the power needed to operate a range of pneumatic actuators. A maximum average power of nearly 3 W with a remarkably high efficiency (recovering more than 20% of the mechanical energy expended during walking) was harvested. The system was fabricated using a state-of-the-art stacked laminate assembly of textiles. To optimize our system, a mechano-fluidic model was developed and validated against experimental results. The use of our system is demonstrated in powering a textile-based assistive device as well as a supernumerary arm used to augment human capability.
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    A wearable textile-based pneumatic energy harvesting system for assistive robotics
    (AAAS, 2022) Shveda, Rachel A.; Rajappan, Anoop; Yap, Te Faye; Liu, Zhen; Bell, Marquise D.; Jumet, Barclay; Sanchez, Vanessa; Preston, Daniel J.
    Wearable assistive, rehabilitative, and augmentative devices currently require bulky power supplies, often making these tools more of a burden than an asset. This work introduces a soft, low-profile, textile-based pneumatic energy harvesting system that extracts power directly from the foot strike of a user during walking. Energy is harvested with a textile pump integrated into the insole of the user’s shoe and stored in a wearable textile bladder to operate pneumatic actuators on demand, with system performance optimized based on a mechano-fluidic model. The system recovered a maximum average power of nearly 3 W with over 20% conversion efficiency—outperforming electromagnetic, piezoelectric, and triboelectric alternatives—and was used to power a wearable arm-lift device that assists shoulder motion and a supernumerary robotic arm, demonstrating its capability as a lightweight, low-cost, and comfortable solution to support adults with upper body functional limitations in activities of daily living.