qFeature
This package contains statistical routines for extracting features from multivariate time-series data which can then be used for subsequent multivariate statistical analysis to identify patterns and anomalous behavior. It calculates local linear or quadratic regression model fits to moving windows for each series and then summarizes the model coefficients across user-defined time intervals for each series. These methods are domain agnostic—but they have been successfully applied to a variety of domains, including commercial aviation and electric power grid data.
Single-Crystal Technology Holds Promise for Next-Generation Lithium-Ion Batteries
Scientists have created a single-crystal, nickel-rich cathode that is hardier and more efficient than before—important progress on the road to better lithium-ion batteries for electric vehicles.
Affordable, Reliable and Efficient-Energy Research is PNNL Focus at ARPA-E Energy Innovation Summit
New Grid-Forming Inverter Models Help Utilities Plan for a Renewable Future
PNNL and collaborators developed new models—recently approved by the U.S. Western Electricity Coordinating Council (WECC)—to help utilities understand how new grid-forming inverter technology will enhance grid stability.
TOROIDAL MULTIPASS ABSORPTION DEVICE
U.S. Patent No. 7,876,443 and references therein discloses a method of creating a multipass cell having a toroidal configuration in which light is injected into the cavity via a hole or penetration into the wall of the reflective toroidal surface. Subsequent to this, a similar cavity is described in the scientific literature that provides additional design guidance for constructing a typical cell.[i],[ii] Both of the referenced papers also describe an absorbing mask that is placed against the cell wall to suppress unwanted reflections which the authors state contribute to coherent noise, often referred to as 'fringing" as the main laser beam interferes with stray reflections that can occur if the launch angle into the cell does not adhere to the value determined by the design equations. These interference patterns contribute noise to the desired signal and degrade the instrument's sensitivity. We disclose an alternate method of injecting light into a toroidal multipass cell using a small mirror (either plane or with optical power) affixed to the wall of the cell in place of a hole or penetration. This approach simplifies construction and offers a path to reduced construction costs and potential replication methods such as casting, injection molding, 3D printing, electroforming or metal spinning. [i] B. Tuzson, M. Mangold, H. Looser, A. Manninen, and L. Emmenegger, 'Compact multipass optical cell for laser spectroscopy", Opt. Lett., Vol 38 (3), 257-259 (2013) [ii] M. Mangold, B. Tuzson, M. Hundt, J. Jagerska, H. Looser, and L. Emmenegger, 'Circular paraboloid reflection cell for laser spectroscopic gas analysis", JOSA A, Vol. 33 (5), 913-919 (2016). U.S. Patent No. 7,876,443 and references therein discloses a method of creating a multipass cell having a toroidal configuration in which light is injected into the cavity via a hole or penetration into the wall of the reflective toroidal surface. Subsequent to this, a similar cavity is described in the scientific literature that provides additional design guidance for constructing a typical cell.[i],[ii] Both of the referenced papers also describe an absorbing mask that is placed against the cell wall to suppress unwanted reflections which the authors state contribute to coherent noise, often referred to as 'fringing" as the main laser beam interferes with stray reflections that can occur if the launch angle into the cell does not adhere to the value determined by the design equations. These interference patterns contribute noise to the desired signal and degrade the instrument's sensitivity. We disclose an alternate method of injecting light into a toroidal multipass cell using a small mirror (either plane or with optical power) affixed to the wall of the cell in place of a hole or penetration. This approach simplifies construction and offers a path to reduced construction costs and potential replication methods such as casting, injection molding, 3D printing, electroforming or metal spinning. [i] B. Tuzson, M. Mangold, H. Looser, A. Manninen, and L. Emmenegger, 'Compact multipass optical cell for laser spectroscopy", Opt. Lett., Vol 38 (3), 257-259 (2013) [ii] M. Mangold, B. Tuzson, M. Hundt, J. Jagerska, H. Looser, and L. Emmenegger, 'Circular paraboloid reflection cell for laser spectroscopic gas analysis", JOSA A, Vol. 33 (5), 913-919 (2016).
Sensors and Batteries: Never Small Enough?
The world is becoming reliant on increasingly smaller sensors that improve daily life in many ways. A PNNL-led paper takes a closer look at these technologies and their future development for environmental and sensitive species monitoring.
New Energy Storage System Strengthens Air Force Base’s Resilience
PNNL teamed up with multiple agencies to install a battery energy storage system at a South Dakota Air Force base.