Gavin Wiggins

Gavin Wiggins

Hello, I'm a research scientist at the Oak Ridge National Laboratory involved in various modeling, simulation, and programming activities. I currently work on external instrument control for neutron equipment and interconnected device programming. Previous areas of research include fluidized bed reactors, battery cells and battery packs, rotor dynamics, water treatment, and biomass pyrolysis. I am also creator of the Un1ts macOS app, Chemics Python package, BioComp web app, and the Genja static website generator. I was organizer of the KnoxPy Python users group along with the Knoxville CocoaHeads group for iOS and macOS developers. See the sections below for information about my software projects, presentations, and publications.

Email   /   GitHub   /   Mastodon

GitHub Sponsors   /   Patreon   /   Buy Me A Coffee   /   PayPal


My open-source tools, Mac apps, and programming projects are listed below.

An open-source web tool for estimating biomass composition from ultimate and chemical analysis data. This web app is built in Python using the Streamlit package. It's hosted for free on GitHub so the initial loading time may be slow.

A comprehensive unit converter for the Mac. The original version of the app was written in Objective-C and was temporarily removed from the App Store. I have rereleased Un1ts as a completely new version written in Swift and SwiftUI to support the latest features of macOS.

WeathrClip provided current weather conditions, 5-day forecast, hourly forecast, and precipitation radar for the Mac and iPhone. I discontinued this app because the Weather Underground API is no longer available.

A Python package for chemical reactor engineering. This open-source package contains functions for performing calculations in the field of chemical and fluidization engineering.

Swift Programming for macOS
There are plenty of books, videos, and online resources for developing iOS apps. Despite the fact that iPhone and iPad apps require a Mac for code development, there is little information about actually creating native Mac applications. This website demonstrates various aspects of modern Mac app development using the latest versions of Swift and SwiftUI. Hopefully the examples will provide a useful resource for Mac developers.

Pythonic Programming
There are numerous resources for learning Python but sometimes you just want to see a straightforward example of the language. This website is a collection of code examples using the Python programming language.

Computing with Julia
The Julia programming language is a high-level, high-performance languauge that is suitable for scientific computing applications. This website presents various aspects of the language along with code examples.

C++ Programs
The purpose of this website and accompanying examples is to provide simple C++ programming examples with brief descriptions of the code.


My presentations and posters from conferences and meetups are provided below as PDF documents.

Best practices for documenting a scientific Python project
US-RSE conference in Chicago, IL on October 16-18, 2023.

GPU Programming with Metal
ORNL Software Expo in Oak Ridge, TN on September 25, 2023.

Disadvantages of Julia
Julia for ORNL Science Workshop in Oak Ridge, TN on July 18, 2022.

An open-source one-dimensional model for bubbling fluidized bed reactors
Workshop on Multiphase Flow Science presented online on August 3, 2021.

Using Lists in Python
KnoxPy online meetup in Knoxville, TN on October 1, 2020.

Getting Started with Python
KnoxPy online meetup in Knoxville, TN on September 10, 2020.

String formatting in Python
KnoxPy meetup in Knoxville, TN on May 14, 2020.

Reduced-Order Modeling Techniques for Fluidized-Bed Biomass Pyrolysis
TC Biomass conference in Rosemont, IL on October 7, 2019.

Python Workshop
KnoxPy meeting in Knoxville, TN on September 5, 2019.

A Pythonic Equivalent Circuit Model for Battery Research
SciPy 2019 conference in Austin, TX on July 10, 2019.

Using Python to Model Biomass Pyrolysis Reactors
SciPy 2019 conference in Austin, TX on July 10, 2019.

Unit Conversion in Swift
Knoxville CocoaHeads meetup in Knoxville, TN on April 29, 2019.

Combining high and low-order computational models to simulate biomass fast pyrolysis reactors
AIChE Spring Meeting and 8th World Congress on Particle Technology in Orlando, FL on April 23, 2018.

Scraping with Selenium
KnoxPy meetup in Knoxville, TN on April 5, 2018.

Realm Mobile Database
Knoxville CocoaHeads meetup in Knoxville, TN on April 18, 2017.

Modeling the impact of biomass particle size distribution and shape on heating behavior during fast pyrolysis
TCS 2016 Symposium in Chapel Hill, NC on November 1, 2016.

Modeling the impact of biomass particle residence time on fast pyrolysis yield and composition
AIChE Annual Meeting in San Francisco, CA on November 13, 2016.

Firebase for iOS
Knoxville CocoaHeads meetup in Knoxville, TN on August 16, 2016.

NSUserDefaults in Swift
Knoxville CocoaHeads meetup in Knoxville, TN on April 19, 2016.

Overview of NumPy in Python
KnoxPy meetup in Knoxville, TN on April 7, 2016.

An Introduction to Git and GitHub
Knoxville CocoaHeads meetup in Knoxville, TN on October 20, 2015.

Resolution Independence with PaintCode
Knoxville CocoaHeads meetup in Knoxville, TN on June 9, 2015.

Modeling Thermochemical Biomass Pyrolysis in Python
PyKnoxville meetup in Knoxville, TN on April 8, 2015.

Low-order modeling of biomass particle mixing and reaction in a bubbling-bed fast pyrolysis reactor
AIChE 2014 Annual Meeting in Atlanta, GA on November 20, 2014.

Particle-scale computational modeling of woody biomass pyrolysis
TCS 2014 Symposium in Denver, CO on September 4, 2014.


My journal articles, conference papers, and other technical articles are listed below. If you do not have access to a publication, please contact me and I will be genuinely delighted to send you a copy of the manuscript. Publications are also listed on my ORCID profile.

Modeling hydrodynamic and biomass pyrolysis effects of recycled product gases in a bubbling fluidized bed reactor
Biomass and Bioenergy, volume 184, pages 107172, 2024.

Best practices for documenting a scientific Python project
US-RSE conference in Chicago, IL on October 16-18, 2023. Also available on Zenodo.

Using Chemical Reactor Models to Predict Fluidized Bed Pyrolysis Yields of Biomass Feedstocks
Oak Ridge National Laboratory, ORNL/TM-2021/2335, 2022.

Liionpack: A Python package for simulating packs of batteries with PyBaMM
Journal of Open Source Software, volume 7, number 70, page 4051, 2022.

Multiscale CFD simulation of biomass fast pyrolysis with a machine learning derived intra-particle model and detailed pyrolysis kinetics
Chemical Engineering Journal, volume 431, page 133853, 2022.

Impacts of Anisotropic Porosity on Heat Transfer and Off-Gassing during Biomass Pyrolysis
Energy and Fuels, volume 35, issue 24, pages 20131-20141, 2021.

Investigating biomass composition and size effects on fast pyrolysis using global sensitivity analysis and CFD simulations
Chemical Engineering Journal, volume 421, part 2, article 127789, 2021.

Assessment of a detailed biomass pyrolysis kinetic scheme in multiscale simulations of a single-particle pyrolyzer and a pilot-scale entrained flow pyrolyzer
Chemical Engineering Journal, volume 418, article 129347, 2021.

Validation and application of a multiphase CFD model for hydrodynamics, temperature field and RTD simulation in a pilot-scale biomass pyrolysis vapor phase upgrading reactor
Chemical Engineering Journal, volume 388, article 124279, 2020.

Integrated Particle- and Reactor-Scale Simulation of Pine Pyrolysis in a Fluidized Bed
Energy and Fuels, volume 32, issue 10, pages 10683-10694, 2018.

Chemics-Reactors: A Preliminary Python Program for Implementing Network Models of Multiphase Reactors
Technical Report, number ORNL/TM-2017/748, 2018.

Simulating Biomass Fast Pyrolysis at the Single Particle Scale
From the book 'Fast Pyrolysis of Biomass', chapter 11, pages 231-253, 2017.

Low-Order Modeling of Internal Heat Transfer in Biomass Particle Pyrolysis
Energy and Fuels, volume 30, issue 6, pages 4960-4969, 2016.

Development of a Low-Order Computational Model for Biomass Fast Pyrolysis: Accounting for Particle Residence Time
Technical Report, number ORNL/TM-2016/69, 2016.

Coupling DAEM and CFD for simulating biomass fast pyrolysis in fluidized beds
Journal of Analytical and Applied Pyrolysis, volume 117, pages 176-181, 2016.

Biomass Particle Models with Realistic Morphology and Resolved Microstructure for Simulations of Intraparticle Transport Phenomena
Energy and Fuels, volume 29, issue 1, pages 242-254, 2015.

Evaluation of Biomass and Coal Briquettes for a Spreader Stoker Boiler Using an Experimental Furnace — Modeling and Test
Thesis, Clemson University, 2011.

System Modeling of ORNL's 20 MW(t) Wood-fired Gasifying Boiler
Conference: American Flame Research Committee, Pacific Rim Combustion Symposium, 2010.

Updated on May 7, 2024 by Gavin Wiggins
Made on a Mac 🍎. Hosted on GitHub Pages.