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Enhancing Photophoretic Levitation U...

Celenza, Thomas,

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Enhancing Photophoretic Levitation Using Three-Dimensional Structures for Flight in the Mesosphere and on Mars /

Record Type:	Electronic resources : Monograph/item
Title/Author:	Enhancing Photophoretic Levitation Using Three-Dimensional Structures for Flight in the Mesosphere and on Mars // Thomas Celenza.
Author:	Celenza, Thomas,
Description:	1 electronic resource (201 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 86-07, Section: B.
Contained By:	Dissertations Abstracts International86-07B.
Subject:	Mechanical engineering. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31560842
ISBN:	9798302182494

Enhancing Photophoretic Levitation Using Three-Dimensional Structures for Flight in the Mesosphere and on Mars /
Celenza, Thomas,

Enhancing Photophoretic Levitation Using Three-Dimensional Structures for Flight in the Mesosphere and on Mars /Thomas Celenza. - 1 electronic resource (201 pages)

Source: Dissertations Abstracts International, Volume: 86-07, Section: B.

Current propulsion and flight mechanisms limit atmospheric observations. The mesosphere is too dense for satellites and too thin for typical planes and balloons, with similar conditions found in the Martian atmosphere, especially at Olympus Mons. Photophoresis, the movement of gas molecules due to light, has been studied for microscale objects like aerosols. When applied to ultrathin, ultralight macroscale objects, levitation occurs. These objects, such as plates and disks with microstructures, absorb visible light and heat up. The resulting temperature changes pump gas molecules through microchannels and cause a recoil force from molecules striking the hotter surface. These combined effects produce enough force to levitate centimeter-scale objects with no moving parts, especially at air pressures in the mesosphere. We designed photophoretic aircraft with 3D hollow geometries to pump ambient air through sidewalls, creating a high-speed jet. Simulations and parametric studies optimized these geometries, showing potential for kilogram-scale payloads for meter-scale aircraft 50 to 80 km above Earth's surface. We fabricated millimeter-scale structures using microfabrication methods to experimentally investigate levitation and enhance the photophoretic force. This included developing a scalable manufacturing method for enhanced temperature gradient-induced levitation of 3D geometries and a new experimental method to measure and compare photophoretic forces of solid versus porous objects. Finally, we explored solar buoyancy to transport the structures to the mesosphere and discussed their potential applications for carrying sensors to measure GPS and state properties in situ.

English

ISBN: 9798302182494Subjects--Topical Terms:

649730
Mechanical engineering.
Subjects--Index Terms:

Photophoresis

Enhancing Photophoretic Levitation Using Three-Dimensional Structures for Flight in the Mesosphere and on Mars /
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502 $b Ph.D. $c University of Pennsylvania $d 2024.
520 $a Current propulsion and flight mechanisms limit atmospheric observations. The mesosphere is too dense for satellites and too thin for typical planes and balloons, with similar conditions found in the Martian atmosphere, especially at Olympus Mons. Photophoresis, the movement of gas molecules due to light, has been studied for microscale objects like aerosols. When applied to ultrathin, ultralight macroscale objects, levitation occurs. These objects, such as plates and disks with microstructures, absorb visible light and heat up. The resulting temperature changes pump gas molecules through microchannels and cause a recoil force from molecules striking the hotter surface. These combined effects produce enough force to levitate centimeter-scale objects with no moving parts, especially at air pressures in the mesosphere. We designed photophoretic aircraft with 3D hollow geometries to pump ambient air through sidewalls, creating a high-speed jet. Simulations and parametric studies optimized these geometries, showing potential for kilogram-scale payloads for meter-scale aircraft 50 to 80 km above Earth's surface. We fabricated millimeter-scale structures using microfabrication methods to experimentally investigate levitation and enhance the photophoretic force. This included developing a scalable manufacturing method for enhanced temperature gradient-induced levitation of 3D geometries and a new experimental method to measure and compare photophoretic forces of solid versus porous objects. Finally, we explored solar buoyancy to transport the structures to the mesosphere and discussed their potential applications for carrying sensors to measure GPS and state properties in situ.
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710 2 $a University of Pennsylvania. $b Mechanical Engineering and Applied Mechanics. $e degree granting institution. $3 3821391
720 1 $a Bargatin, Igor $e degree supervisor.
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