Machine-learning-assisted long-term G functions for bidirectional aquifer thermal energy storage system operation
Not Available
25 ENERGY STORAGE↗
SEARCH · Engineering Papers
Results for “long term”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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The convergence of lactic acid microbiomes and metabolites in long-term electrofermentation
Not Available
Leininger, Aaron↗
Evaluating long-term model-based scenarios of the energy system
Energy-economic models are used to provide science-based decision support in a variety of contexts. Analyses using these tools often involve defining a “reference” scenario, which serves as a counterfactual against which alternative scenarios are compared. Evaluating scenarios, including reference scenarios, is critical for establishing the credibility of the analyses these models support. We propose a framework for evaluating energy system scenarios which consists of three parts – a qualitative storyline, quantitative metrics, and evaluation criteria. We apply this framework to the reference scenario for GCAM-USA, a version of the global human-Earth system model GCAM (Global Change Assessment Model) with state-level detail in the United States, focusing on the evolution of the electric power sector. We develop new visual analytic tools to facilitate the evaluation of model outcomes in 51 sub-national regions, and demonstrate how scenario performance can be tracked and compared across four quantifications of the GCAM-USA reference scenario.
29 ENERGY PLANNING, POLICY, AND ECONOMY↗
Thermal energy storage composites with preformed expanded graphite matrix and paraffin wax for long-term cycling stability and tailored thermal properties
Harvesting solar energy, preventing hot spots in electronics, transport of temperature-sensitive materials, and capture and repurposing of thermal energy require a latent heat thermal energy storage (TES) system to store/discharge heat repeatedly. For the practical application of phase change material (PCM) composites within TES systems, reliable thermal performance throughout its operational lifetime is essential. Nevertheless, the reliability of thermal conductivity in multi-phase composites over relevant numbers (>10 3 ) of melt/freeze cycles has barely been studied, particularly for composites containing fillers for thermal conductivity enhancement. Here, we introduce a preform-type expanded graphite (EG)/paraffin wax composite possessing highly robust heat transfer and storage properties even after 10,000 melt/freeze cycles. To achieve such excellent reliability, comparative studies on the combined influence of fabrication process, particle size, EG vol%, binder amount, and compaction on both magnitude and robustness of thermal conductivity were undertaken. Our parametric study has yielded a trade-off between thermal conductivity and latent heat. Based on our modeling, 20 vol% EG approaches the case where all EG particles are well-connected thermally while 10 vol% EG is close to loosely connected fillers in the matrix. Thermal conductivity of our paraffin composites containing 20 vol% EG (25.1 W·m -1 ·K -1 ) is highest among other EG/paraffin composites without aligned EG in the literature. After 10,000 thermal cycling, negligible conductivity fading was observed for the 10 vol% EG composite, while reduction in latent heat remained within 10% for all 10, 14, 17 and 20 vol% EG samples. Here we anticipate this work provides insight on suitable recipe for desirable magnitude and robustness of thermal conductivity of EG/paraffin composites.
25 ENERGY STORAGE↗
Long-term tree and stand growth dynamics after thinning of various intensities in a temperate mixed forest
Not Available
Moreau, Guillaume↗
The World-wide Randomized Antibiotic Envelope Infection Prevention (WRAP-IT) trial: Long-term follow-up
Not Available
Mittal, Suneet↗
An environment-adaptive protection scheme with long-term reward for distribution networks
Not Available
Cui, Qiushi↗
Transmission-distribution long-term volt-var planning considering reactive power support capability of distributed PV
High penetration of grid-edge, inverter-based photovoltaic (PV) can cause significant voltage fluctuations not only at the distribution but also at the sub-transmission levels due to PV output intermittency. Traditional reactive power planning approaches do not consider intermittency, nor the possibility of coordinating the control of existing and future volt-ampere reactive resources. This paper proposes a reactive power planning tool for sub-transmission systems to mitigate voltage violations and fluctuations caused by high PV penetration and intermittency with a minimum investment cost. The planning tool coordinates with an optimization-based volt-var operational tool for: a) modeling the coordination of all existing var assets in both sub-transmission and distribution systems to reduce the need of new equipment, and b)selecting a set of scenarios with voltage violations, derived from PV intermittency c) testing the final investment decision. The tool obtains an investment need for each intermittency scenario with a proposed optimal power-flow framework with efficient techniques to handle a high number of discrete variables. Two options are provided for final planning decision: i) a conservative direct combination of investment need solutions and ii) a machine learning-based selection of representative investment needs at most time steps. The final investment decision options are verified using a realistic large-scale sub-transmission system and 5-minute PV and load data. The results show a significant voltage performance improvement with a lower investment cost for additional var equipment compared to conventional approaches.
14 SOLAR ENERGY↗
Deep Probabilistic Koopman: Long-term time-series forecasting under periodic uncertainties
Not Available
Mallen, Alex T. (ORCID:0000000251201350)↗
High-performance and cost-effective membrane electrode assemblies for advanced proton exchange membrane water electrolyzers: Long-term durability assessment
In this work, improved activity and durability performance of a two-cell (86 cm 2 ) proton exchange membrane water electrolyzer (PEMWE) stack is reported for the first time. Both membrane electrode assemblies (MEAs) contain one order of magnitude lower platinum group metal (PGM) loadings compared to the state-of-the-art PEMWEs and incorporate novel Pt recombination layers. The high-performance and cost-effective MEAs are fabricated by the unique reactive spray deposition technology (RSDT). This advanced methodology allows for one-step fabrication of MEAs and ensures precise control and distribution of the catalyst composition and loading. The RSDT-fabricated MEAs contain only 0.2 and 0.3 mg PGM cm –2 loading in the cathode and anode electrodes, respectively, and demonstrate excellent activity and durability for over 3000 h of operation at industrially-relevant operating conditions without showing significant loss in performance. This novel work shows that a significant cost reduction for PEMWEs is achieved while maintaining excellent durability, high catalysts activities, and low hydrogen cross-over.
Proton exchange membrane water electrolyzer↗
Long-Term Maintenance of Acinar Cells in Human Submandibular Glands After Radiation Therapy
In a combined retrospective and prospective study, human salivary glands were investigated after radiation treatment for head and neck cancers. The aim was to assess acinar cell loss and morphologic changes after radiation therapy and to determine whether irradiated salivary glands have regenerative potential.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Long-Term Outcomes of Patients With Early Stage Nonbulky Hodgkin Lymphoma Treated With Combined Modality Therapy in the Stanford V Trials (the G4 and G5 Studies)
Combined modality therapy (CMT) is standard therapy for early-stage Hodgkin lymphoma (ESHL). We previously reported excellent outcomes with the abbreviated Stanford V regimen. Herein we report updated results with median follow-up >10 years on survival, therapy-related late effects, and impact of disease risk factors on patient outcomes.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Radiation-Induced Myocardial Fibrosis in Long-Term Esophageal Cancer Survivors
Radiation-induced cardiac toxicity is a potential lethal complication. The aim of this study was to assess whether there is a dose-dependent relationship between radiation dose and myocardial fibrosis in patients who received neoadjuvant chemoradiation (nCRT) for esophageal cancer (EC).
62 RADIOLOGY AND NUCLEAR MEDICINE↗