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Papers by Michelle Gervasio

2021 Systems and Information Engineering Design Symposium (SIEDS)

Completed in the summer of 2020, Sweet Briar College’s 26,000 square foot greenhouse is home to a... more Completed in the summer of 2020, Sweet Briar College’s 26,000 square foot greenhouse is home to a variety of vegetables, providing fresh food for the campus dining hall as well as giving students the opportunity to learn about food sustainability. The current horticulture practices in the greenhouse are functional, but growth rates and processing could be improved with a hydroponic system. Hydroponics is a subset of horticulture in which plants are rooted in nutrient-rich water rather than soil. A hydroponics system would not only serve as an educational opportunity for Sweet Briar’s environmental science students but would also allow for the experimentation of a variety of new plants and growing methods. Some other benefits of a hydroponic system include a significant decrease in water waste, reduced need for pesticides and herbicides, and more efficient use of space.Through extensive research and compliance with customer specifications, we determined that using a Nutrient Film Technique with an A-frame design would be the best option for the Sweet Briar College greenhouse. The NFT water flow method is one of the most respected in the field of hydroponics, as it is typically extremely reliable and user-friendly. A thin film of nutrient-laden water gently passes over the roots of the system, allowing the plant to absorb as needed. Incorporating this technique with an A-frame design would allow for the best use of space while still allowing each plant to receive optimal sunlight as compared to other vertically designed hydroponic systems. By incorporating microcontrollers and sensors to monitor the water level, pH, and electrical conductivity in the reservoir, our system will be able to dispense nutrient solution and water as needed. We plan to measure and track plant growth and survivability based on both new plant growth as well as fruit/vegetable production with the goal of exceeding that of standard soil-grown plants of the same variety and anticipate having results by April 2021. We would also like to track system water loss, either from leaks, evaporation, or absorption, by monitoring the main water reservoirs with the goal of 75% efficiency over the course of a month. Finally, we would like to measure the amount of light the plants are getting throughout the day, using either a photoresistor and microcontroller or a lux meter, to determine if additional synthetic lighting options would be beneficial to the system. We plan to have the system fully functioning and operable by May 2021.

Journal of The European Ceramic Society, Apr 1, 2019

Advanced theory and simulations, Mar 15, 2019

ACS Applied Materials & Interfaces, Mar 12, 2015

Journal of Materials Science, Apr 24, 2015

Soft Matter, 2017

Imprint lithography has been explored as a method to transfer arrays of patterned features onto p... more Imprint lithography has been explored as a method to transfer arrays of patterned features onto pure polymers and polymer/metallic nanoparticle composites. Despite the success of this method for those materials, it has never been achieved on the sub-micron scale with polymer-oxide particle hybrids. This study patterns ZnO-PMMA (poly(methyl methacrylate)) hybrids via imprint lithography from co-suspensions of PMMA and ZnO nanoparticles in anisole from 1 vol% to 20 vol% ZnO solids loading. ZnO nanoparticles are functionalized with nonanoic acid to disperse the nanoparticles in anisole with dissolved PMMA. The feature fidelity of the patterned arrays decreases with increasing ZnO content, indicating an increase in particle agglomeration as the ZnO particle content increases. Feature size, ZnO content, and ZnO nanoparticle agglomeration are critical factors influencing the photoluminescence (PL) intensity. The ZnO solids loading at a 500 nm feature size needs to be 10 vol% or higher for the enhanced PL response. When the ridge size increases to 1 μm, ZnO solids loading as low as 1 vol% is feasible. This method of lithographic patterning of nanoparticle-polymer suspensions can be applied to a wide variety of hybrid devices and has the potential to open many applications including optical devices and biomedical screening.

Journal of Physical Chemistry C, May 18, 2017

Advanced Theory and Simulations, 2019

This study uses a Monte Carlo simulation method to evaluate the agglomeration behaviors of differ... more This study uses a Monte Carlo simulation method to evaluate the agglomeration behaviors of different ZnO nanoparticle and polymethacrylate hybrid suspensions in an organic solvent. Interaction energies are primarily from the steric layer on the particle surfaces. The effects of nanoparticle size, steric layer thickness, particle content, and total solids loading are evaluated based on the average agglomerate size and agglomeration rate. Smaller particle, thicker steric layer, lower particle content, and higher solids loading are desirable factors to stabilize a suspension. Agglomerate size and agglomeration rate increase continuously with increasing particle content in the hybrids from 1 to 50 vol%. A drastic transition from an unstable suspension to a stable suspension occurs when the total solids loading of the suspension increases to greater than 10 vol%. This work provides important guidance for co‐dispersing nanoparticles and dissolved polymer chains in organic solvents.

Journal of the European Ceramic Society, 2019

The Journal of Physical Chemistry C, 2017

Soft matter, Jan 23, 2017

Imprint lithography has been explored as a method to transfer arrays of patterned features onto p... more Imprint lithography has been explored as a method to transfer arrays of patterned features onto pure polymers and polymer/metallic nanoparticle composites. Despite the success of this method for those materials, it has never been achieved on the sub-micron scale with polymer-oxide particle hybrids. This study patterns ZnO-PMMA (poly(methyl methacrylate)) hybrids via imprint lithography from co-suspensions of PMMA and ZnO nanoparticles in anisole from 1 vol% to 20 vol% ZnO solids loading. ZnO nanoparticles are functionalized with nonanoic acid to disperse the nanoparticles in anisole with dissolved PMMA. The feature fidelity of the patterned arrays decreases with increasing ZnO content, indicating an increase in particle agglomeration as the ZnO particle content increases. Feature size, ZnO content, and ZnO nanoparticle agglomeration are critical factors influencing the photoluminescence (PL) intensity. The ZnO solids loading at a 500 nm feature size needs to be 10 vol% or higher for...

ACS applied materials & interfaces, Jan 27, 2015

In this manuscript, natural materials were combined into a single "pot" to produce flex... more In this manuscript, natural materials were combined into a single "pot" to produce flexible, highly fire resistance, and bio-inspired coatings on flexible polyurethane foam (PUF). In one-step, PUF was coated with a fire protective layer constructed of a polysaccharide binder (starch or agar), a boron fire retardant (boric acid or derivative), and a dirt char former (montmorillonite clay). Nearly all the coatings produced a 63% reduction in a critical flammability value, the peak heat release rate (PHRR). One formulation produced a 75% reduction in PHRR. This technology was validated in full-scale furniture fire tests, where a 75% reduction in PHRR was measured. At these PHRR values, this technology could reduce the fire threat of furniture from significant fire damage in and beyond the room of fire origin to being contained to the burning furniture. This flammability reduction was caused by three mechanisms - the gas phase and condensed phase processes of the boron fire re...

Journal of Materials Science, 2015

2021 Systems and Information Engineering Design Symposium (SIEDS)

Completed in the summer of 2020, Sweet Briar College’s 26,000 square foot greenhouse is home to a... more Completed in the summer of 2020, Sweet Briar College’s 26,000 square foot greenhouse is home to a variety of vegetables, providing fresh food for the campus dining hall as well as giving students the opportunity to learn about food sustainability. The current horticulture practices in the greenhouse are functional, but growth rates and processing could be improved with a hydroponic system. Hydroponics is a subset of horticulture in which plants are rooted in nutrient-rich water rather than soil. A hydroponics system would not only serve as an educational opportunity for Sweet Briar’s environmental science students but would also allow for the experimentation of a variety of new plants and growing methods. Some other benefits of a hydroponic system include a significant decrease in water waste, reduced need for pesticides and herbicides, and more efficient use of space.Through extensive research and compliance with customer specifications, we determined that using a Nutrient Film Technique with an A-frame design would be the best option for the Sweet Briar College greenhouse. The NFT water flow method is one of the most respected in the field of hydroponics, as it is typically extremely reliable and user-friendly. A thin film of nutrient-laden water gently passes over the roots of the system, allowing the plant to absorb as needed. Incorporating this technique with an A-frame design would allow for the best use of space while still allowing each plant to receive optimal sunlight as compared to other vertically designed hydroponic systems. By incorporating microcontrollers and sensors to monitor the water level, pH, and electrical conductivity in the reservoir, our system will be able to dispense nutrient solution and water as needed. We plan to measure and track plant growth and survivability based on both new plant growth as well as fruit/vegetable production with the goal of exceeding that of standard soil-grown plants of the same variety and anticipate having results by April 2021. We would also like to track system water loss, either from leaks, evaporation, or absorption, by monitoring the main water reservoirs with the goal of 75% efficiency over the course of a month. Finally, we would like to measure the amount of light the plants are getting throughout the day, using either a photoresistor and microcontroller or a lux meter, to determine if additional synthetic lighting options would be beneficial to the system. We plan to have the system fully functioning and operable by May 2021.

Journal of The European Ceramic Society, Apr 1, 2019

Advanced theory and simulations, Mar 15, 2019

ACS Applied Materials & Interfaces, Mar 12, 2015

Journal of Materials Science, Apr 24, 2015

Soft Matter, 2017

Imprint lithography has been explored as a method to transfer arrays of patterned features onto p... more Imprint lithography has been explored as a method to transfer arrays of patterned features onto pure polymers and polymer/metallic nanoparticle composites. Despite the success of this method for those materials, it has never been achieved on the sub-micron scale with polymer-oxide particle hybrids. This study patterns ZnO-PMMA (poly(methyl methacrylate)) hybrids via imprint lithography from co-suspensions of PMMA and ZnO nanoparticles in anisole from 1 vol% to 20 vol% ZnO solids loading. ZnO nanoparticles are functionalized with nonanoic acid to disperse the nanoparticles in anisole with dissolved PMMA. The feature fidelity of the patterned arrays decreases with increasing ZnO content, indicating an increase in particle agglomeration as the ZnO particle content increases. Feature size, ZnO content, and ZnO nanoparticle agglomeration are critical factors influencing the photoluminescence (PL) intensity. The ZnO solids loading at a 500 nm feature size needs to be 10 vol% or higher for the enhanced PL response. When the ridge size increases to 1 μm, ZnO solids loading as low as 1 vol% is feasible. This method of lithographic patterning of nanoparticle-polymer suspensions can be applied to a wide variety of hybrid devices and has the potential to open many applications including optical devices and biomedical screening.

Journal of Physical Chemistry C, May 18, 2017

Advanced Theory and Simulations, 2019

This study uses a Monte Carlo simulation method to evaluate the agglomeration behaviors of differ... more This study uses a Monte Carlo simulation method to evaluate the agglomeration behaviors of different ZnO nanoparticle and polymethacrylate hybrid suspensions in an organic solvent. Interaction energies are primarily from the steric layer on the particle surfaces. The effects of nanoparticle size, steric layer thickness, particle content, and total solids loading are evaluated based on the average agglomerate size and agglomeration rate. Smaller particle, thicker steric layer, lower particle content, and higher solids loading are desirable factors to stabilize a suspension. Agglomerate size and agglomeration rate increase continuously with increasing particle content in the hybrids from 1 to 50 vol%. A drastic transition from an unstable suspension to a stable suspension occurs when the total solids loading of the suspension increases to greater than 10 vol%. This work provides important guidance for co‐dispersing nanoparticles and dissolved polymer chains in organic solvents.

Journal of the European Ceramic Society, 2019

The Journal of Physical Chemistry C, 2017

Soft matter, Jan 23, 2017

Imprint lithography has been explored as a method to transfer arrays of patterned features onto p... more Imprint lithography has been explored as a method to transfer arrays of patterned features onto pure polymers and polymer/metallic nanoparticle composites. Despite the success of this method for those materials, it has never been achieved on the sub-micron scale with polymer-oxide particle hybrids. This study patterns ZnO-PMMA (poly(methyl methacrylate)) hybrids via imprint lithography from co-suspensions of PMMA and ZnO nanoparticles in anisole from 1 vol% to 20 vol% ZnO solids loading. ZnO nanoparticles are functionalized with nonanoic acid to disperse the nanoparticles in anisole with dissolved PMMA. The feature fidelity of the patterned arrays decreases with increasing ZnO content, indicating an increase in particle agglomeration as the ZnO particle content increases. Feature size, ZnO content, and ZnO nanoparticle agglomeration are critical factors influencing the photoluminescence (PL) intensity. The ZnO solids loading at a 500 nm feature size needs to be 10 vol% or higher for...

ACS applied materials & interfaces, Jan 27, 2015

In this manuscript, natural materials were combined into a single "pot" to produce flex... more In this manuscript, natural materials were combined into a single "pot" to produce flexible, highly fire resistance, and bio-inspired coatings on flexible polyurethane foam (PUF). In one-step, PUF was coated with a fire protective layer constructed of a polysaccharide binder (starch or agar), a boron fire retardant (boric acid or derivative), and a dirt char former (montmorillonite clay). Nearly all the coatings produced a 63% reduction in a critical flammability value, the peak heat release rate (PHRR). One formulation produced a 75% reduction in PHRR. This technology was validated in full-scale furniture fire tests, where a 75% reduction in PHRR was measured. At these PHRR values, this technology could reduce the fire threat of furniture from significant fire damage in and beyond the room of fire origin to being contained to the burning furniture. This flammability reduction was caused by three mechanisms - the gas phase and condensed phase processes of the boron fire re...

Journal of Materials Science, 2015