Gavin Wiggins

Gavin Wiggins

I'm a research scientist at the Oak Ridge National Laboratory. I currently develop computational models to simulate fluidized bed reactors, battery packs, and rotating machinery. I am the former organizer of the KnoxPy Python users group, the Knoxville CocoaHeads group for iOS and macOS developers, and the MacDevs YouTube channel. See the sections below for information about my software development, presentations, and publications.

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BioComp. 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. [URL]

Un1ts. 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. [URL]

WeathrClip. 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.

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

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. [Read]

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. [Read]

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. [Read]

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

MacDevs. The MacDevs YouTube channel was where misfits, rebels, troublemakers, and the ones who think differently shared their knowledge about developing Mac apps. I deleted the channel due to lack of content.


Disadvantages of Julia. Julia for ORNL Science Workshop. Presented at Oak Ridge National Laboratory on July 18, 2022. [PDF]

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

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

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

String formatting in Python. KnoxPy meeting in Knoxville, TN on May 14, 2020. Live demo via Jupyter Notebook.

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

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

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

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

Unit Conversion in Swift. Knoxville CocoaHeads meeting in Knoxville, TN on April 29, 2019. [PDF]

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. [PDF]

Scraping with Selenium. KnoxPy meeting in Knoxville, TN on April 5, 2018. [PDF]

Realm Mobile Database. Knoxville CocoaHeads meeting in Knoxville, TN on April 18, 2017. [PDF]

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. [PDF]

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. [PDF]

Firebase for iOS. Knoxville CocoaHeads meeting in Knoxville, TN on August 16, 2016. [PDF]

NSUserDefaults in Swift. Knoxville CocoaHeads meeting in Knoxville, TN on April 19, 2016. [PDF]

Overview of NumPy in Python. KnoxPy meeting in Knoxville, TN on April 7, 2016. [PDF]

An Introduction to Git and GitHub. Knoxville CocoaHeads meeting in Knoxville, TN on October 20, 2015. [PDF]

Resolution Independence with PaintCode. Knoxville CocoaHeads meeting in Knoxville, TN on June 9, 2015. [PDF]

Modeling Thermochemical Biomass Pyrolysis in Python. PyKnoxville meeting in Knoxville, TN on April 8, 2015. [PDF]

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. [PDF]

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


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.

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

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

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. [URL]

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

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. [URL]

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. [URL]

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. [URL]

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

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

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

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

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

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

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. [URL]

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

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

Updated on April 17, 2023 by Gavin Wiggins.
Made on a Mac. Hosted on GitHub Pages.