Publications

Results 601–700 of 99,299

Search results

Jump to search filters

Port Electrification Handbook: A reference to aid U.S. port energy transitions

Mammoli, Andrea A.; Idso, Shannon K.; Tufner, Francis K.; Wang, Dexin; Calkins, Ryan

Port electrification can take many forms, such as electrifying cargo handling equipment or deploying a microgrid to power critical port infrastructure. To help evaluate the growing challenge of increased electrification and its impacts on the system, Pacific Northwest National Laboratory developed this Port Electrification Handbook with support from the U.S. Department of Energy, Office of Electricity’s Microgrids R&D [research and development] program. The goals of this handbook are the following: (1) Help port operators and planners evaluate different electrification technologies; (2) Explain how these technologies could aid and impact ports and surrounding communities; and (3) Provide step-by-step considerations for port electrification.

More Details

Metrological Guidance for the Calibration of Laboratory Glassware

Mackrory, Andrew J.

This report provides technical guidance for the calibration of laboratory glassware to help the practitioner achieve traceability to the International System of Units and meet customer quality requirements. The discussion of traceability uses the National Institute of Standards and Technology’s seven essential elements of traceability as a framework. The guidance also includes how to determine when calibration is necessary, practical tips, and helpful references.

More Details

Performance-based earthquake early warning for tall buildings

Earthquake Spectra

Ghahari, Farid; Sargsyan, Khachik; Parker, Grace A.; Swensen, Daniel; Celebi, Mehmet; Haddadi, Hamid; Taciroglu, Ertugrul

The ShakeAlert Earthquake Early Warning (EEW) system aims to issue an advance warning to residents on the West Coast of the United States seconds before the ground shaking arrives, if the expected ground shaking exceeds a certain threshold. However, residents in tall buildings may experience much greater motion due to the dynamic response of the buildings. Therefore, there is an ongoing effort to extend ShakeAlert to include the contribution of building response to provide a more accurate estimation of the expected shaking intensity for tall buildings. Currently, the supposedly ideal solution of analyzing detailed finite element models of buildings under predicted ground-motion time histories is not theoretically or practically feasible. The authors have recently investigated existing simple methods to estimate peak floor acceleration (PFA) and determined these simple formulas are not practically suitable. Instead, this article explores another approach by extending the Pacific Earthquake Engineering Research Center (PEER) performance-based earthquake engineering (PBEE) to EEW, considering that every component involved in building response prediction is uncertain in the EEW scenario. While this idea is not new and has been proposed by other researchers, it has two shortcomings: (1) the simple beam model used for response prediction is prone to modeling uncertainty, which has not been quantified, and (2) the ground motions used for probabilistic demand models are not suitable for EEW applications. In this article, we address these two issues by incorporating modeling errors into the parameters of the beam model and using a new set of ground motions, respectively. We demonstrate how this approach could practically work using data from a 52-story building in downtown Los Angeles. Using the criteria and thresholds employed by previous researchers, we show that if peak ground acceleration (PGA) is accurately estimated, this approach can predict the expected level of human comfort in tall buildings.

More Details

Pathfinding Process Development for the Realization of Atomic Precision Advanced Manufacturing (APAM)-Based Vertical Tunneling Field Effect Transistors for Enhanced Energy Efficiency

Anderson, Evan M.; Allemang, Christopher R.; Arose, Christopher D.J.; Lu, Tzu M.; Schmucker, Scott W.; Sheridan, Thomas R.; Ivie, Jeffrey A.; Campbell, Deanna M.; Vigil, Ashlyn P.R.; Hawkins, Alisha; Gamache, Phillip; Gao, Xujiao; Weingartner, Thomas A.; Misra, Shashank

Abstract not provided.

Heat Transfer Through a Passive Fire Protective Board from an Impinging Hydrogen Flame

Felipe, Christina; Blaylock, Myra L.; Lafleur, Angela (Chris); Bran Anleu, Gabriela A.

This report documents analysis to determine whether a hydrogen jet flame impinging on a tunnel ceiling structure could result in permanent damage to the Callahan tunnel in Boston, Massachusetts. This tunnel ceiling structure consists of a passive fire protective board supported by stainless steel hangers anchored to the tunnel ceiling with epoxy. Three types of fire protective boards were considered to determine whether heat from the flame could reach the stainless-steel hangers and the epoxy and cause the ceiling structure to collapse. Heat transfer analyses performed showed that the temperature remains constant where the steel hangers are attached to the passive fire protective board. According to these results, the passive fire protective board should provide adequate protection to the tunnel structure in this release scenario. Tunnel structures with similar suspended fire-resistant liner board materials should protect the integrity of the structure against the extremely low probability of an impinging hydrogen jet flame.

More Details

Data Based Shock Test Specification

Gilliam, James S.; Payne, Lloyd R.; Montoya, Angela C.

It is vital that avionic packages used for testing and certifying the reliability and safety of U.S. nuclear weapons with platform aircraft survive exposure to shock environments during transportation and delivery. The objective of this research was to characterize the response to these transportation shock environments delivering accurate shock test specifications in order to set laboratory programming material and device certification rigor. Responses to shock events were analyzed in the frequency domain via the Shock Response Spectrum (SRS). Shocks were then grouped based on respective behavior of maximum response accelerations which were pseudorandomly resampled and compared to test data to form test specifications based on the MinerPalmgren hypothesis. In addition to discovering significant over testing in current shock specifications, a new systematic, data-driven approach to designing shock specifications was formulated.

More Details

Understanding dislocation plasticity of single crystalline Ta micropillars under dynamic loading

Journal of Materials Research and Technology

Aragon, Nicole; Lim, Hojun; Nguyen, Phu C.; Ryu, Ill

Recent experimental findings have shown that tantalum single crystals display strong anisotropy during Taylor impact testing in stark contrast to isotropic deformation in polycrystalline counterparts. In this study, a coupled dislocation dynamics and finite element model was developed to simulate the complex stress field under dynamic loading of a Taylor impact test and track the intricate evolution of the dislocation microstructure. Our model allowed us to investigate detailed motion of dislocations and their mutual interactions and the effect of varying simulation parameters, such as sample size, initial dislocation density, crystallographic orientation, and temperature. Simulation results show good agreement with experimental observations and shed light on the mechanical response at small-scale under extreme loading conditions. In addition, resolved shear stress analysis incorporating the effect of shear stress from impact was performed to quantitatively support and provide a means to understand the model predictions of the impact foot shape.

More Details

Synthesis and crystal structure of 2,9-diamino-5,6,11,12-tetrahydrodibenzo[a,e]cyclooctene

Acta Crystallographica Section E: Crystallographic Communications

Valdez, Nichole R.; Nagel, Eric; Redline, Erica; Rodriguez, Mark A.; Staiger, Chad L.; Dugger, Jason; Foster, Jeffrey

The cis- form of diaminodibenzocyclooctane (DADBCO, C16H18N2) is of interest as a negative coefficient of thermal expansion (CTE) material. The crystal structure was determined through single-crystal X-ray diffraction at 100 K and is presented herein.

More Details

Mid-circuit Measurement & Branching in QSCOUT: A Ping-Pong Teleportation Exemplar Program

Landahl, Andrew J.; Rudinger, Kenneth M.; Russo, Antonio E.; Ruzic, Brandon P.; Yale, Christopher G.; Clark, Susan M.

This document is intended to help users program the new mid-circuit measurement (MCM) and classical branching capabilities of the Quantum Scientific Computing Open User Testbed (QSCOUT). Here, we present and explain an exemplar “ping-pong teleportation” program that makes repeated MCM and branching calls. The program is written in Jaqal, the quantum assembly language used by QSCOUT. This document is intended to accompany a companion Jupyter notebook Exemplar_one_bit_teleportation_pingpong.ipynb.

More Details

Quantifying the impact of inverter clipping on photovoltaic performance and soiling losses

Renewable Energy

Micheli, Leonardo; Muller, Matthew; Theristis, Marios; Smestad, Greg P.; Almonacid, Florencia; Fernandez, Eduardo F.

It is commonly assumed that cleaning photovoltaic (PV) modules is unnecessary when the inverter is undersized because clipping will sufficiently mask the soiling losses. Clipping occurs when the inverter's AC size is smaller than the overall modules' DC capacity and leads to the conversion of only part of the PV-generated DC energy into AC. This study evaluates the validity of this assumption, theoretically investigating the current magnitude of clipping and its effect on soiling over the contiguous United States. This is done by modelling energy yield, clipping and soiling across a grid of locations. The results show that in reality, under the current deployment trends, inverter undersizing minimally affects soiling, as it reduces these losses by no more than 1%absolute. Indeed, clipping masks soiling in areas where losses are already low, whereas it has a negligible effect where soiling is most significant. However, the mitigation effects might increase under conditions of lower performance losses or more pronounced inverter undersizing. In any case, one should take into account that degradation makes clipping less frequent as systems age, also decreasing its masking effect on soiling. Therefore, even if soiling was initially mitigated by the inverter undersizing, its effect would become more visible with time.

More Details

Convergence in simulating global soil organic carbon by structurally different models after data assimilation

Global Change Biology

Mishra, Umakant; Tao, Feng; Houlton, Benjamin Z.; Huang, Yuanyuan; Wang, Ying P.; Manzoni, Stefano; Ahrens, Bernhard; Jiang, Lifen; Huang, Xiaomeng; Luo, Yiqi

Current biogeochemical models produce carbon–climate feedback projections with large uncertainties, often attributed to their structural differences when simulating soil organic carbon (SOC) dynamics worldwide. However, choices of model parameter values that quantify the strength and represent properties of different soil carbon cycle processes could also contribute to model simulation uncertainties. Here, we demonstrate the critical role of using common observational data in reducing model uncertainty in estimates of global SOC storage. Two structurally different models featuring distinctive carbon pools, decomposition kinetics, and carbon transfer pathways simulate opposite global SOC distributions with their customary parameter values yet converge to similar results after being informed by the same global SOC database using a data assimilation approach. The converged spatial SOC simulations result from similar simulations in key model components such as carbon transfer efficiency, baseline decomposition rate, and environmental effects on carbon fluxes by these two models after data assimilation. Moreover, data assimilation results suggest equally effective simulations of SOC using models following either first-order or Michaelis–Menten kinetics at the global scale. Nevertheless, a wider range of data with high-quality control and assurance are needed to further constrain SOC dynamics simulations and reduce unconstrained parameters. New sets of data, such as microbial genomics-function relationships, may also suggest novel structures to account for in future model development. Overall, our results highlight the importance of observational data in informing model development and constraining model predictions.

More Details

Direction-dependent elastic wave scattering and mode coupling in elastic plates

Haberman, Michael; Parker, Samuel D.

Asymmetric scattering is a phenomenon in which the field scattered from a discontinuity is dependent on the direction of incidence. In waveguide systems such as elastic plates, the existence of multiple propagating modes provides a platform to explore asymmetric scattering through direction-dependent mode coupling. This paper describes this concept in the context of reciprocal systems and how to utilize it in a general manner.

More Details

Autonomous Emergency Landing for Fixed-Wing Aircraft with Energy-Constrained Closed-Loop Prediction

Journal of Aerospace Information Systems

Mazumdar, Anirban; Deal, Samuel J.; Nichols, Hayden L.

This paper presents a new approach for autonomous motion planning for aircraft suffering from a loss-of-thrust emergency. Specifically, we show how modifications to the Closed-Loop Rapidly exploring Random Trees (CL-RRT) framework combined with controlled energy dissipation can enable rapid and effective kinodynamic motion planning. This CL-RRT Glide algorithm uses closed-loop prediction not only for node connections but also to estimate the remaining energy and prune infeasible paths. This greatly speeds up the search process, which is essential for emergency situations. In addition, we improve the ability of the gliding aircraft to reach a goal position and energy state. We do so by creating a Dissipative Total Energy Control Scheme (TECS). Dissipative TECS enables the glider to lose excess altitude in order to reach a desired energy level. Simulation results illustrate how the proposed methods enable faster motion planning. We also integrate the system into a small unmanned aerial vehicle system and experimentally demonstrate autonomous glide planning and execution during a motor-failure event. This type of algorithm can primarily benefit unmanned aircraft but can also serve to assist pilots in stressful emergency situations.

More Details

Review of the second charged-particle transport coefficient code comparison workshop

Physics of Plasmas

Stanek, Lucas J.; Hansen, Stephanie B.; Kononov, Alina K.; Cochrane, Kyle; Clay III, Raymond C.; Townsend, Joshua P.; Dumi, Amanda; Lentz, Meghan; Melton, Cody A.; Baczewski, Andrew D.; Knapp, Patrick F.; Haines, Brian M.; Hu, S.X.; Murillo, Michael S.; Stanton, Liam G.; Whitley, Heather D.; Baalrud, Scott D.; Babati, Lucas J.; Bethkenhagen, Mandy; Blanchet, Augustin; Collins, Lee A.; Faussurier, Gerald; French, Martin; Johnson, Zachary A.; Karasiev, Valentin V.; Kumar, Shashikant; Nichols, Katarina A.; Petrov, George M.; Recoules, Vanina; Redmer, Ronald; Ropke, Gerd; Schorner, Maximilian; Shaffer, Nathaniel R.; Sharma, Vidushi; Silvestri, Luciano G.; Soubiran, Francois; Suryanarayana, Phanish; Tacu, Mikael; White, Alexander J.

We report the results of the second charged-particle transport coefficient code comparison workshop, which was held in Livermore, California on 24-27 July 2023. This workshop gathered theoretical, computational, and experimental scientists to assess the state of computational and experimental techniques for understanding charged-particle transport coefficients relevant to high-energy-density plasma science. Data for electronic and ionic transport coefficients, namely, the direct current electrical conductivity, electron thermal conductivity, ion shear viscosity, and ion thermal conductivity were computed and compared for multiple plasma conditions. Additional comparisons were carried out for electron-ion properties such as the electron-ion equilibration time and alpha particle stopping power. Overall, 39 participants submitted calculated results from 18 independent approaches, spanning methods from parameterized semi-empirical models to time-dependent density functional theory. In the cases studied here, we find significant differences—several orders of magnitude—between approaches, particularly at lower temperatures, and smaller differences—roughly a factor of five—among first-principles models. We investigate the origins of these differences through comparisons of underlying predictions of ionic and electronic structure. The results of this workshop help to identify plasma conditions where computationally inexpensive approaches are accurate, where computationally expensive models are required, and where experimental measurements will have high impact.

More Details

Gasb-to-Si Direct Wafer Bonding and Thermal Budget Considerations for Photonic Applications

Martinez, William M.; Anderson, Evan M.; Wood, Michael G.; Friedmann, Thomas A.; Arterburn, Shawn C.; Reyna, Robert; Gutierrez, Jordan E.; Harris, Christian A.; Kotula, Paul G.; Cummings, Damion P.; Bahr, Matthew N.; Patel, Victor J.; Muhowski, Aaron; Hawkins, Samuel D.; Long, Christopher M.; Klem, John F.; Shank, Joshua; Wygant, Melissa L.

Abstract not provided.

Results 601–700 of 99,299
Results 601–700 of 99,299