Emissivity prediction of functionalized surfaces using artificial intelligence

Tuning surface emissivity has been of great interest in thermal radiation applications, such as thermophotovoltaics and passive radiative cooling. As a low-cost and scalable technique for manufacturing surfaces with desired emissivities, femtosecond laser surface processing (FLSP) has recently drawn enormous attention. Despite the versatility offered by FLSP, there is a knowledge gap in accurately predicting the outcome emissivity prior to fabrication. In this work, we demonstrate the immense advantage of employing artificial intelligence (AI) techniques to predict the emissivity of complex surfaces. For this aim, we used FLSP to fabricate 116 different aluminum samples. A comprehensive dataset was established by collecting surface characteristics, laser operating parameters, and the measured emissivities for all samples. We demonstrate the successful application of AI in two distinct scenarios: (1) effective emissivity classification solely based on 3D surface morphology images, and (2) emissivity prediction based on surface characteristics and FLSP parameters. These findings open new pathways towards extended implementation of AI to predict various surface properties in functionalized samples or extract the required fabrication parameters via reverse engineering

Near-unity broadband omnidirectional emissivity via femtosecond laser surface processing

It is very challenging to achieve near perfect absorption/emission that is both broadband and omnidirectional while utilizing a scalable fabrication process. Femtosecond laser surface processing is an emerging low-cost and large-scale manufacturing technique used to directly and permanently modify the surface properties of a material. The versatility of this technique to produce tailored surface properties has resulted in a rapidly growing number of applications. Here, we demonstrate near perfect, broadband, omnidirectional emissivity from aluminum surfaces by tuning the laser surface processing parameters including fluence, pulse count, and the ambient gas. Full-wave simulations and experimental results prove that the obtained increase in emissivity is mainly a result of two distinct features produced by femtosecond laser surface processing: the introduction of microscale surface features and the thick oxide layer. This technique leads to functionalized metallic surfaces that are ideal for emerging applications, such as passive radiative cooling and thermal management of spacecraft

Tailorable Broadband Wide-angle Emissivity Produced Using Femtosecond Laser Surface Processing

Typically, metals are highly reflective in the visible and deep into the infrared (IR) spectrum. Surfaces with high electromagnetic absorption or emission in the IR spectrum are of great interest due to the wide variety of applications, including passive cooling, thermal solar power generation, and thermal management for spacecraft. The emerging advanced manufacturing technique known as femtosecond laser surface processing (FLSP) is used to directly and permanently alter surfaces on the micro- and nanoscales. By modifying the laser parameters, including fluence (between 0.5 and 4.5 j/cm2), pulse count (200 to 8000 pulses), and the atmospheric environment (nitrogen and air), FLSP produces a wide range of structure morphologies with hierarchical micro- and nanoscale surface features. By controlling these laser processing parameters, the hemispherical emissivity of a metal can be tuned, ranging from nearly zero to unity. In this thesis, a broadband near perfect omnidirectional emissive response is demonstrated for the first time on aluminum and stainless steel using FLSP. Theoretical, statistical, and experimental results prove that the broadband omnidirectional increase in emissivity is mainly due to two interdependent causes: the change in the surface morphology and the growth of a thick, redeposited oxide layer. Femtosecond laser surface processing surfaces that have been optimized for high emissivity show little decrease in emissivity at higher angles in addition to broadband operation in the IR spectrum from 7.5 to 14 μm, making FLSP structures ideal for a wide variety of radiative thermal applications. Advisor: Craig A. Zuhlk

The Lymphoma Epidemiology of Outcomes cohort study: Design, baseline characteristics, and early outcomes

Abstract To address the current and long‐term unmet health needs of the growing population of non‐Hodgkin lymphoma (NHL) patients, we established the Lymphoma Epidemiology of Outcomes (LEO) cohort study (NCT02736357; https://leocohort.org/ ). A total of 7735 newly diagnosed patients aged 18 years and older with NHL were prospectively enrolled from 7/1/2015 to 5/31/2020 at 8 academic centers in the United States. The median age at diagnosis was 62 years (range, 18–99). Participants came from 49 US states and included 538 Black/African‐Americans (AA), 822 Hispanics (regardless of race), 3386 women, 716 age <40 years, and 1513 rural residents. At study baseline, we abstracted clinical, pathology, and treatment data; banked serum/plasma ( N = 5883, 76.0%) and germline DNA ( N = 5465, 70.7%); constructed tissue microarrays for four major NHL subtypes ( N = 1189); and collected quality of life ( N = 5281, 68.3%) and epidemiologic risk factor ( N = 4489, 58.0%) data. Through August 2022, there were 1492 deaths. Compared to population‐based SEER data (2015–2019), LEO participants had a similar distribution of gender, AA race, Hispanic ethnicity, and NHL subtype, while LEO was underrepresented for patients who were Asian and aged 80 years and above. Observed overall survival rates for LEO at 1 and 2 years were similar to population‐based SEER rates for indolent B‐cell (follicular and marginal zone) and T‐cell lymphomas, but were 10%–15% higher than SEER rates for aggressive B‐cell subtypes (diffuse large B‐cell and mantle cell). The LEO cohort is a robust and comprehensive national resource to address the role of clinical, tumor, host genetic, epidemiologic, and other biologic factors in NHL prognosis and survivorship