Unit cell estimation of volumetrically-varying permittivity in additively-manufactured ceramic lattices with X-ray computed tomography

Burden, Edward; Oh, Yongduk; Mummareddy, Bhargavi; Negro, Dylan; Cortes, Pedro; Plessis, Anton du; MacDonald, Eric; Adams, Jack A.; Li, Frank; Rojas, R.G.

doi:10.1016/j.matdes.2021.110032

Cited by 9 publications

(9 citation statements)

References 55 publications

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“…At present however, the unit cell structures used in AM graded index components do not seem to obey the MG mixing law [5]. Rather, they more closely follow the Bruggeman and Capacitive model, which are both better approximated by the Linear mixing rule [25]. To maximize gain, research into producing unit cell arrangements that follow the MG mixing law is therefore still needed.…”

Section: Discussionmentioning

confidence: 99%

An Empirical Loss Model for an Additively Manufactured Luneburg Lens Antenna

LaRocca

Mirotznik

2022

ACES Journal

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This research applies Effective Medium Theory and 3D Finite Element Analysis to model the transmissive loss through a waveguide fed additively manufactured Luneburg lens. New results are presented that provide rational function approximations for accurately modeling the aperture, beam, and radiation loss factors of the antenna. It introduces a normalized loss tangent and shows that the loss factors are dependent on the product of this parameter and the lens radius. Applying the constraint that the main beam of the radiation pattern contains 50% of accepted power, a maximum useful radius is tabulated for common polymers used in additive manufacturing.

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Section: Discussionmentioning

confidence: 99%

An Empirical Loss Model for an Additively Manufactured Luneburg Lens Antenna

LaRocca

Mirotznik

2022

ACES Journal

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“…Similar concepts and ways of thinking has been championed by South African researchers and partnering institutions globally [2,51,123,[219][220][221][222][223][224][225][226][227][228][229][230][231][232]. Through these efforts more than a dozen publications have emanated focusing on extrusion-based 3D concrete structures [51,229,230,232], X-ray tomography [219,222,225-227, 233,234], biomimicry in additive manufacturing [51,222,223,231] and critical reviews of AM applications in various industries [2,224].…”

Section: Additive Manufacturing In Building and Constructionmentioning

confidence: 99%

“…The RAPDASA team also forge strong international collaboration with entities such as Global Alliance of Rapid Prototyping Associations (GARPA) [25,33]. These activities are augmented by universities and research councils across South Africa [2,51,123,[219][220][221][222][223][224][225][226][227][228][229][230][231][232][263][264][265][266]. These institutions have additive manufacturing research groupings with medium to highend 3D printers for polymers and metals.…”

Section: Additive Manufacturing Awareness In South Africamentioning

confidence: 99%

“…The rest of the African continent has much to learn from South Africa especially in areas of AM research [2,51,123,[219][220][221][222][223][224][225][226][227][228][229][230][231][232]244,269,270]. The increasing funding programs through the Collaborative Program in Additive Manufacturing is commendable and a case in point.…”

Section: Additive Manufacturing Awareness In South Africamentioning

confidence: 99%

“…The increasing funding programs through the Collaborative Program in Additive Manufacturing is commendable and a case in point. This has brought about cooperation between many research institutions and centres of higher learning to drive fundamental and applied research, resource sharing, robust scholarly engagement, cross pollination and co-creation of knowledge and products in ways that could beneficiate and add value to the mineral wealth of the continent [2,51,123,[219][220][221][222][223][224][225][226][227][228][229][230][231][232]244,269,270]. This has also led to a vibrant AM ecosystem bridging the gap between the academy and industry.…”

Section: Additive Manufacturing Awareness In South Africamentioning

confidence: 99%

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Global perspective and African outlook on additive manufacturing research − an overview

et al. 2022

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Additive manufacturing (AM) technologies and advances made globally in medicine, construction, aerospace, and energy sectors are discussed. The paper further explores the current state of AM innovation and development landscape in Africa as a late comer to this area of smart manufacturing. Peer-reviewed and published literature were retrieved from Scopus database from 2005 to 2021 and analysed. In Africa, out of 500 published articles, South Africa has the highest research throughput, whereas about two-thirds of the continent is not actively participating in this burgeoning field. The main AM techniques most widely used are selective laser melting, fused deposition modelling, and direct energy deposition. Globally, there is an interplay of computational (machine learning and mechanistic models) and experimental approaches to understanding the physical metallurgy of AM techniques and processes. Though this trend is consistent with global practices, Africa lags the world in AM technologies, a niche that could leapfrog the manufacturing sector. Thus, Africa need to foster collaborative partnership within and globally to become an active global player in this industry.

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Thermoelectric properties of polyvinylpyrrolidone/polyaniline‐mixed Bi₂Te₃ composites prepared by electrospinning

et al. 2023

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Composite fibers of bismuth telluride (Bi 2 Te 3 ) with polyaniline (PANI) and polyvinylpyrrolidone (PVP), synthesized via electrospinning in different ratios, were studied. Initially, three solutions were synthesized in different ratios of PVP and composite (Bi 2 Te 3 and PANI). However, due to the loading capacity of polymer only two samples were successfully synthesized. The formation and surface morphology of as-prepared and compacted fibers were studied by scanning electron microscopy. The X-ray diffraction confirmed the increase in crystalline phase of the composites after compaction. The influence of functional groups on the thermal and electrical conductivity as well as the existence of various polymer functional groups in pure and composite samples were revealed by Fourier transform infrared spectroscopy. Thermogravimetric analysis and differential scanning calorimetric were carried out simultaneously up to 800 K, which revealed the thermal stability of composite up-to 473 K and a glass transition temperature (T g ) of $412 K for the composites. Diffuse reflectance spectroscopy confirmed the decrease in the bandgap from $3 to $1.2 eV of the compacted fibers. The thermopower of the as-prepared and compacted fibers increased significantly compared with pure Bi 2 Te 3 and PANI, while the thermal conductivity decreased to 0.45 Wm À1 K À1 . As a result, zT was enhanced from 1.7 Â 10 À10 to 1.7 Â 10 À1 in the composite samples near room temperature.

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Unit cell estimation of volumetrically-varying permittivity in additively-manufactured ceramic lattices with X-ray computed tomography

Cited by 9 publications

References 55 publications

An Empirical Loss Model for an Additively Manufactured Luneburg Lens Antenna

An Empirical Loss Model for an Additively Manufactured Luneburg Lens Antenna

Global perspective and African outlook on additive manufacturing research − an overview

Thermoelectric properties of polyvinylpyrrolidone/polyaniline‐mixed Bi₂Te₃ composites prepared by electrospinning

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Unit cell estimation of volumetrically-varying permittivity in additively-manufactured ceramic lattices with X-ray computed tomography

Cited by 9 publications

References 55 publications

An Empirical Loss Model for an Additively Manufactured Luneburg Lens Antenna

An Empirical Loss Model for an Additively Manufactured Luneburg Lens Antenna

Global perspective and African outlook on additive manufacturing research − an overview

Thermoelectric properties of polyvinylpyrrolidone/polyaniline‐mixed Bi2Te3 composites prepared by electrospinning

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Product

Resources

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Thermoelectric properties of polyvinylpyrrolidone/polyaniline‐mixed Bi₂Te₃ composites prepared by electrospinning