2020
Rachel Moglen, Pattanun Chanpiwat, Steven Gabriel
A dynamic programming formulation designed to optimally schedule demand response events to maximize savings for retail electric providers. Also considers the effects of price uncertainty on savings through the use of stochastic dynamic programming.
Energy Systems
Billy Champion, Steven Gabriel, Ahti Salo
A risk-based, stochastic multi-period model with binary decision variables at each stage has usefulness for planning the retrofitting of buildings for energy conservation.
Energy Systems
Simon Risanger, Stein-Erik Fleten, Steven A. Gabriel
Inverse equilibrium modeling is a data-driven method that fit parameters of an equilibrium model in order to minimize the deviation from an observation. This paper shows how to use Karush-Kuhn-Tucker (KKT)conditions to invert equilibrium problems.
IEEE Transactions on Power Systems
Steven A. Gabriel, Marina Leal, Martin Schmidt
This work presents different continuous reformulations of the binary constrained mixed complementarity problem, common in many real-world engineering-economic systems such as energy markets, transportation networks, or supply chains. The main idea is to obtain purely continuous reformulations so that local NLP solvers can be applied that are usually faster compared to mixed-integer solvers.
opus4.kobv.de
2019
Pattanun Chanpiwat , Steven A. Gabriel , Rachel L. Moglen , Michael J. Siemann
A practical means to analyze and cluster residential households into homogeneous groups based on electricity load, a top priority for retail electric providers so that they can effectively plan and conduct demand response.
ASME Journal of Engineering for Sustainable Buildings and Cities
2020
Ramsay Blake Nuwayhid, Angelique Jarry, Keith Gregorczyk, Gary W. Rubloff
Demonstrates a thermal atomic layer deposition process for sodium phosphorus oxynitride (NaPON), a thin-film solid-state electrolyte for sodium-ion batteries. NaPON could become a viable solid-state electrolyte or passivation layer for solid-state sodium-ion batteries.
ACS Applied Materials and Interfaces
Emily Sahadeo, Yang Wang, Chuan-Fu Lin, Yue Li, Gary W. Rubloff, Sang Bok Lee
The polymerization behavior of DOL with multivalent Mg and Al salts is investigated. The researchers conclude that strong Lewis acid cations such as Al3+ and Mg2+ can catalyze DOL polymerization and their Lewis acidity, and ability to catalyze the reaction, is influenced by the associated anion. These discoveries could help expand the applications of Lewis acid catalysts in polymerization reactions and give insight into the importance of the properties of metal salts. These insights may also be critical in deciding whether to utilize DOL as a solvent for Mg battery systems and what electrolyte compositions may be ideal.
Chemical Communications
Matthew Widstrom, Kyle Ludwig, Jesse Matthews, Angelique Jarry, Metecan Erdi, Arthur Cresce, Gary Rubloff, Peter Kofinas
Ionic conductivity needs to be improved significantly for solid polymer electrolytes to be considered competitive alternatives to organic liquid electrolytes for battery technology. The strategy employed in this paper is to promote polymer microstructures that facilitate ion transport by developing an amorphous rather than crystalline polymer matrix.
Electrochimica Acta
Haotian Wang, Keith E. Gregorczyk, Sang Bok Lee, Gary W. Rubloff, Chuan-Fu Lin
In combining organometallic with organic precursors, molecular layer deposition (MLD) offers not only an expanded portfolio of molecular combinations but specifically the possibility of tuning mechanical properties for more robust functionality. This is appealing for applications in energy storage, where ion transport in and out of electrodes causes significant stress/strain cycling. It is particularly opportune for Li ion solid state batteries (LISSBs), where electrode and solid electrolyte structures are usually arranged densely for high power and energy. Despite diverse MLD applications to date, little prior research has been aimed at Li-containing MLD materials and processes. This work demonstrates the synthesis of a Li-containing organic thin film using organic-inorganic MLD reaction between LiOtBu and PD.
The Journal of Physical Chemistry C
2019
Angelique Jarry, Emily Hitz, Jake Ballard, Carine L Margez, Joong Sun Park, Thomas A Greszler, Chuan-Fu Lin, Gary W. Rubloff
Among the different rechargeable battery technologies available, Co/Ni/Mn-based Li-ion systems appear to be a leading contender for automotive applications as a result of their high specific energy. However, the high operating potential of this system is outside the thermodynamic stability window of standard organic carbonate-based electrolytes. This results in electrolyte oxidation with transition metal dissolution and gas formation at the electrode/electrolyte interface during cycling, which leads to severe loss of electrochemical performance. To address these challenges, many strategies are currently being investigated, ranging from the development of new electrodes and electrolytes to the improvement of commercial Li-ion systems by surface engineering of the interfaces.
In this work, we mitigate parasitic interfacial processes in start/stop batteries by atomic layer deposition (ALD). We develop an Al2O3 or LiPON conformal artificial SEI layer on LMO and LTO electrodes and study its effect on the Li-ion batteries failure modes with differential electrochemical mass spectroscopy (DEMS), X-ray Photoelectron Spectroscopy (XPS) and ICP measurements. The beneficial impact of the protection layer on the kinetics of the gassing, metal dissolution and associated chemical cross-talk was clearly identified. The presence of a protection layer at the LMO surface, in particular of a 10 nm LiPON conformal layer, mitigate the electrolyte oxidation at high voltage at 60°C with a significant reduction of the amount of H2 produced. The formation of metal complexes and subsequent poisoning of the SEI is also attenuated. Interestingly, counter intuitively, the ratio of the inorganic to organic components of the SEI is lowered by the presence of an inorganic protection layer. The correlation between the nature of the electrode protection layer, the electrode's surface activity, and associated organic electrolyte oxidation pathways will be presented and discussed.
Electrochemical Society Meeting Abstracts
2020
Liuxian Zhao, Miao Yu
A flattened structural Luneburg lens (FSLL) based on structural thickness variations is designed by using the quasi-conformal transformation (QCT)technique.
Journal of the Acoustical Society of America
Liuxian Zhao, Changquan Lai, Miao Yu
An alternative structural Luneburg lens which has a refractive index that varies smoothly with its radial distance as a result of a changing thickness.
Mechanical Systems and Signal Processing
Liuxian Zhao, Miao Yu
The paper explores the concept of a structural Luneburg Lens as a design framework for performing dynamic structural tailoring to obtain a structural wave cloak and a structural waveguide.
Nature Scientific Reports
Liuxian Zhao, Changquan Lai, Miao Yu
The paper proposes an alternative structural Luneburg lens with a refractive index that varies smoothly with its radial distance as a result of a changing thickness. This simple lens design enables a continuous gradient of refractive index, which allows flexural wave propagation to be manipulated and overcomes limitations in existing wave manipulation devices.
arXiv.org
