Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “evaluation framework”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,801 records · Page 100
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Two-Way Option Contracts That Facilitate Adaptive Water Reallocation in the Western United States

Many water markets in the western United States (U.S.) have the ability to reallocate water temporarily during drought, often as short-term water rights leases from lower value irrigated activities to higher value urban uses. Regulatory approval of water transfers, however, typically takes time and involves high transaction costs that arise from technical and legal analyses, discouraging short-term leasing. This leads municipalities to protect against drought-related shortfalls by purchasing large volumes of infrequently used permanent water rights. High transaction costs also result in municipal water rights rarely being leased back to irrigators in wet or normal years, reducing agricultural productivity. This research explores the development of a multi-year two-way option (TWO) contract that facilitates leasing from agricultural-to-urban users during drought and leasing from urban-to agricultural users during wet periods. The modeling framework developed to assess performance of the TWO contracts includes consideration of the hydrologic, engineered, and institutional systems governing the South Platte River Basin in Colorado where there is growing competition for water between municipalities (e.g., the city of Boulder) and irrigators. The modeling framework is built around StateMod, a network-based water allocation model used by state regulators to evaluate water rights allocations and potential rights transfers. Results suggest that the TWO contracts could allow municipalities to maintain supply reliability with significantly reduced rights holdings at lower cost, while increasing agricultural productivity in wet and normal years. Additionally, the TWO contracts provide irrigators with additional revenues via net payments of option fees from municipalities.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Chapter 10: Economics and Perspectives of Hydrogen Electroproduction Techniques

Techno-economic analysis (TEA) plays a critical role in assessing the cost of a technology relative to the current market, in identifying high impact areas for research and development investment, and in informing relevant stakeholders. In this chapter we discuss three main topics: (1) an overview of TEA, its processes, methods, and considerations for developing a good TEA framework; (2) description of the U.S. Department of Energy's H2A Production Model which is used for evaluating their portfolio of hydrogen production research; and (3) a synopsis of currently published H2A case studies illustrating the application of techno-economic analysis to hydrogen production technologies. These technologies include polymer membrane and solid oxide electrolysis, photo-electrochemical, methane steam reforming, coal gasification and use of biomass (via gasification or bio-derived liquids) and solar thermal routes to hydrogen. From the analyses comparisons between various technological approaches can be made in terms of costs, implementation, investment and versatility.

08 HYDROGEN↗
DOE OSTI2016

Investigation of a microporous iron( III ) porphyrin framework derived cathode catalyst in PEM fuel cells

In Polymer Electrolyte Membrane Fuel Cells (PEMFCs) the thickness, structure and morphology of the electrode layer play an important role in the cell performance. This effect becomes particularly significant when the cathode catalyst is based on a non-precious metal due to the higher catalyst loadings required to compensate for the lower catalytic activity when compared to Pt based catalysts. In this study, an iron( III ) porphyrin framework material was synthesized and pyrolyzed and its catalytic activity towards the oxygen reduction reaction (ORR) was evaluated using rotating disk electrode (RDE) experiments and single cell testing. Single cell performance was evaluated as a function of the electrode catalyst loading (electrode thickness) and oxygen partial pressure. As expected, the ORR kinetic overpotential was the major contributor to the overall voltage loss. However, the mass transport contribution to the voltage loss became more prominent with small increases in the cathode catalyst loading. Finally, the observed performance is discussed in the context of structure and morphology of the catalyst layer (CL), analyzed through scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Metal-promoted Mo 6 S 8 clusters: a platform for probing ensemble effects on the electrochemical conversion of CO 2 and CO to methanol

Presented in this paper is an investigation of a promising ternary metal sulfide catalyst that is capable of electrochemically converting CO 2 to liquid and gas fuels such as methanol and hydrogen. When promoted by copper, an extended structure of Chevrel-phase Mo 6 S 8 clusters is capable of reducing CO 2 and CO to methanol in aqueous conditions with an overpotential of –0.4 V vs. RHE. H 2 gas is simultaneously and preferentially evolved during this process, contributing to total current densities as high as 35 mA cm –2 . It has been observed that Cu 2 Mo 6 S 8 displays unique catalytic activity in terms of product selectivity, and we attribute this activity to molybdenum sulfide cluster units based on the results of structural, electronic, and electroanalytical characterization. Also discussed is the formulation of an interesting electronic structure–function correlation founded on the basis of X-ray absorption spectroscopic analyses and corroborated by the results of electroanalytical evaluation, where it has been observed that introduction of metal promoting species into the Chevrel-phase framework encourages charge transfer into cluster chalcogen sites.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Mathematical solutions in internal dose assessment: A comparison of Python-based differential equation solvers in biokinetic modeling

Abstract In biokinetic modeling systems employed for radiation protection, biological retention and excretion have been modeled as a series of discretized compartments representing the organs and tissues of the human body. Fractional retention and excretion in these organ and tissue systems have been mathematically governed by a series of coupled first-order ordinary differential equations (ODEs). The coupled ODE systems comprising the biokinetic models are usually stiff due to the severe difference between rapid and slow transfers between compartments. In this study, the capabilities of solving a complex coupled system of ODEs for biokinetic modeling were evaluated by comparing different Python programming language solvers and solving methods with the motivation of establishing a framework that enables multi-level analysis. The stability of the solvers was analyzed to select the best performers for solving the biokinetic problems. A Python-based linear algebraic method was also explored to examine how the numerical methods deviated from an analytical or semi-analytical method. Results demonstrated that customized implicit methods resulted in an enhanced stable solution for the inhaled 60 Co (Type M) and 131 I (Type F) exposure scenarios for the inhalation pathway of the International Commission on Radiological Protection (ICRP) Publication 130 Human Respiratory Tract Model (HRTM). The customized implementation of the Python-based implicit solvers resulted in approximately consistent solutions with the Python-based matrix exponential method ( expm ). The differences generally observed between the implicit solvers and expm are attributable to numerical precision and the order of numerical approximation of the numerical solvers. This study provides the first analysis of a list of Python ODE solvers and methods by comparing their usage for solving biokinetic models using the ICRP Publication 130 HRTM and provides a framework for the selection of the most appropriate ODE solvers and methods in Python language to implement for modeling the distribution of internal radioactivity.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2011

Possibility of narrow resonances in nucleon-nucleon channels

Compound states manifest themselves as bound states, resonances, or primitives, and their character is determined by their interaction with the continuum. If the interaction experiences a perturbation, a compound state can change its manifestation. Phase analysis of nucleon-nucleon scattering indicates the existence of primitives in the {sup 3}S{sub 1}, {sup 1}S{sub 0}, and {sup 3}P{sub 0} channels. Electromagnetic interaction can shift primitives from the unitary cut, turning them into narrow resonances. We evaluate this effect on the {sup 1}S{sub 0} proton-proton scattering channel in the framework of the Simonov-Dyson model. We show that electromagnetic interaction turns a primitve with a mass of 2 000 MeV into a dibaryon resonance of approximately the same mass and a width of 260 keV. Narrow resonances of a similar nature may occur in other nucleon-nucleon channels. Experimental confirmation of the existence of narrow resonances would have important implications for the theory of nucleon-nucleon interaction.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Light-front spin-dependent spectral function and nucleon momentum distributions for a three-body system

Poincare covariant definitions for the spin-dependent spectral function and for the momentum distributions within the light-front Hamiltonian dynamics are proposed for a three-fermion bound system, starting from the light-front wave function of the system. The adopted approach is based on the Bakamjian–Thomas construction of the Poincaré generators, which allows one to easily import the familiar and wide knowledge on the nuclear interaction into a light-front framework. The proposed formalism can find useful applications in refined nuclear calculations, such as those needed for evaluating the European Muon Collaboration effect or the semi-inclusive deep inelastic cross sections with polarized nuclear targets, since remarkably the light-front unpolarized momentum distribution by definition fulfills both normalization and momentum sum rules. As a result, also shown is a straightforward generalization of the definition of the light-front spectral function to an A -nucleon system.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Technoeconomic Analysis of Photovoltaics Module Manufacturing with Thin Silicon Wafers

Reducing silicon usage by adopting thinner wafers can significantly reduce capital expenditure (capex) and cost, and thus accelerate the growth of manufacturing capacity and deployment. In this work, we evaluated potential benefits of thin Si wafers for current and future PV modules. We apply a technoeconomic framework that couples bottom-up cost model, and a cash-flow growth model to analyze PV modules with thin wafers. First, we show that, comparing the current PERC with 160 um thick wafers to the high-efficiency concept with 50 um thin wafers, the capex is reduced from 0.39 to 0.2 $/(W/year) while the cost is from 0.32 to 0.2 $/W. Second, the potential of accelerated deployment is analyzed for the highefficiency thin wafer concept. We found the significant advantages of higher growth rate (~20% relative) and higher deployment plateau (~3 times) than the current PERC modules. modules with thin wafers. First, we show that, comparing the current PERC with 160 um thick wafers to the high-efficiency concept with 50 um thin wafers, the capex is reduced from 0.39 to 0.2 $/(W/year) while the cost is from 0.32 to 0.2 $/W. Second, the potential of accelerated deployment is analyzed for the highefficiency thin wafer concept. We found the significant advantages of higher growth rate (~20% relative) and higher deployment plateau (~3 times) than the current PERC modules.

14 SOLAR ENERGY↗
DOE OSTI2023

VDiSC: An Open Source Framework for Distributed Smart City Vision and Biometric Surveillance Networks

Recent global growth in the interest of smart cities has led to trillions of dollars of investment toward research and development. These connected cities have the potential to create a symbiosis of technology and society and revolutionize the cost of living, safety, ecological sustainability, and quality of life of societies on a world-wide scale. Some key components of the smart city construct are connected smart grids, self-driving cars, federated learning systems, smart utilities, large-scale public transit, and proactive surveillance systems. While exciting in prospect, these technologies and their subsequent integration cannot be attempted without addressing the potential societal impacts of such a high degree of automation and data sharing. Additionally, the feasibility of coordinating so many disparate tasks will require a fast, extensible, unifying framework. To that end, we propose the Distributed Smart City framework for Vision, or VDiSC. VDiSC serves as a unified biometric API harness that allows for seamless evaluation, deployment, and simple pipeline creation for heterogeneous biometric software. VDiSC additionally provides a fully declarative capability for defining and coordinating custom machine learning and sensor pipelines, allowing the distribution of processes across otherwise incompatible hardware and networks. VDiSC ultimately provides a way to quickly configure, hot-swap, and expand large coordinated or federated systems online without interruptions for maintenance. Because much of the data collected in a smart city contains Personally Identifying Information (PII), VDiSC also provides built-in tools and layers to ensure secure and encrypted streaming, storage, and access of PII data across distributed systems.

Brogan, Joel↗
DOE OSTI2013

Reuse of low specific activity material as part of LLWR design optimisation

A final cap will be emplaced over the disposed waste as part of the closure engineering for the UK's Low Level Waste Repository (LLWR). Additional profiling material will be required above the waste to obtain the required land-form. Consideration has been given to the potential opportunity to reuse Low Specific Activity Material (LSAM, defined as up to 200 Bq g{sup -1}) imported from other sites as a component of the necessary profiling material for the final repository cap. Justification of such a strategy would ultimately require a demonstration that the solution is optimal with respect to other options for the long-term management of such materials. The proposal is currently at the initial evaluation stage and seeks to establish how LSAM reuse within the cap could be achieved within the framework of an optimised safety case for the LLWR, should such a management approach be pursued. The key considerations include the following: The LSAM must provide the same engineering function as the remainder of the profiling material. The cap design must ensure efficient leachate collection, drainage and control for Low Level Waste (LLW) (and, by extension, LSAM) during the Period of Authorisation. In the longer term the engineering design must passively direct any accumulating waters preferentially away from surface water systems. An initial design has been developed that would allow the placement of around 220,000 m{sup 3} of LSAM. The potential impact of the proposal has been assessed against the current Environmental Safety Case. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Building water resilience in the face of cascading wildfire risks

Severe wildfire is altering the natural and the built environment and posing risks to environmental and societal health and well-being, including cascading impacts to water systems and built water infrastructure. Research on wildfire-resilient water systems is growing but not keeping pace with the scale and severity of wildfire impacts, despite their intensifying threat. In this study, we evaluate the state of knowledge regarding wildfire-related hazards to water systems. We propose a holistic framework to assess interactions and feedback loops between water quality, quantity, and infrastructure hazards as determinants of post-fire water availability and access. Efforts to address the evolving threat of wildfires to water systems will require more interdisciplinary research on the complex relationships shaping wildfire’s threat to water availability and access. To support this, we need reliable long-term data availability, consistent metrics, greater research in shared contexts, more extensive research beyond the burn area, and multistakeholder collaboration on wildfire risks to water systems.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Toadstool Deep Learning Framework

SAND2025-11741O Toadstool is a deep learning framework and support library that provides PyTorch boiler plate training and testing loops. This enables the user to remember parts and customize a callback interface. Toadstool also provides useful callbacks and other methods for deep learning experimentation. The framework also implements publicly available temperature and calibration methods, model initialization methods, learning rate schedulers, and model evaluation methods. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Heidbrink, Scott↗
DOE OSTI2015

Guided design of copper oxysulfide superconductors

We describe a framework for designing novel materials, combining modern first-principles electronic-structure tools, materials databases, and evolutionary algorithms capable of exploring large configurational spaces. Guided by the chemical principles introduced by Antipov et al., for the design and synthesis of the Hg-based high-temperature superconductors, we apply our framework to screen 333 proposed compositions to design a new layered copper oxysulfide, Hg(CaS)2CuO2. We evaluate the prospects of superconductivity in this oxysulfide using theories based on charge-transfer energies, orbital distillation and uniaxial strain.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Shockley-Queisser analysis of the temperature-efficiency correlation of solar cells in the presence of non-radiative heat transfer

An empirical negative T cell − η correlation has been widely applied, without careful justifications, to evaluate the efficiency ( η ) increase of solar cells due to their temperature ( T cell ) decrease. Here, a framework is introduced to simultaneously compute T cell and η . This model confirms the negative T cell − η correlation if the above-bandgap absorptivity ( α I ) is not suppressed in the optimization of the sub-bandgap reflectivity ( ρ II ) or the infrared emissivity, otherwise it may suggest a positive correlation. It further gives a guideline to enhance η of silicon cells under typical conditions: every 1% increase of α I is equivalent to a 57% increase of ρ II .

14 SOLAR ENERGY↗
DOE OSTI2016

Assessing The Energy Impact Of Traffic Management and Vehicle Hybridization

We provide a review of methodologies previously used to evaluate impacts of transportation systems and changes in transportation infrastructure on energy consumption. We present a new framework that allows estimating the energy impacts of managed traffic lanes in the context of vehicle automation. The presented framework relies on two major components, an integrated transportation system simulator and a powertrain simulator. For the transportation system simulator we propose using integrated transportation system simulator POLARIS. For the powertrain simulator we use AUTONOMIE, a tool funded by the U.S. Department of Energy. Both tools are developed at Argonne National Laboratory. We demonstrate our approach by modelling a transportation corridor along a major highway. Two scenarios are considered, unmanaged, when both trucks and cars use all the lanes of the highway and managed, under which one of the highway lanes is a dedicated lane for truck traffic and trucks are forming platoons using adaptive cruise control technology. We provide the numerical results of the experiment at the end of the paper. We also present the impact of vehicle hybridisation combined with automation on the energy consumption.

Energy Assessment↗
DOE OSTI2023

JetNet: A Python package for accessing open datasets and benchmarking machine learning methods in high energy physics

JetNet is a Python package that aims to increase accessibility and reproducibility for machinelearning (ML) research in high energy physics (HEP), primarily related to particle jets. Basedon the popular PyTorch ML framework, it provides easy-to-access and standardized interfacesfor multiple heterogeneous HEP datasets and implementations of evaluation metrics, lossfunctions, and more general utilities relevant to HEP.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2019

Assessment of the Geomechanical Risks Associated with CO 2 Injection at the FutureGen 2.0 Site: Application of the State of Stress Assessment Tool (SOSAT)

This report presents the results of the application of the State of Stress Assessment Tool (SOSAT) on the FutureGen 2.0 data set. SOSAT was developed as part of the National Risk Assessment Partnership (NRAP) project and provides a unique integrated framework for estimating the state of stress probability distribution at a given depth in the subsurface and evaluating the risk of induced shear and tensile failure resulting from the injection of carbon dioxide (CO 2 ). The approach implemented by SOSAT is based on two deterministic and widely used methods of determining the state of stress (i.e., stress polygon and one-dimensional tectonic-elastic approach). These methods have been modified using a probabilistic approach to account for uncertainties in the input parameters. The methodology proposed in SOSAT was demonstrated using the data obtained for the FutureGen 2.0 project located in the Illinois Basin. Although the FutureGen 2.0 project was suspended by the U.S. Department of Energy prior to the start of injection operations, the extensive characterization efforts undertaken at the storage site have yielded a considerable amount of valuable data about this part of the sedimentary basin. The FutureGen 2.0 storage site was designed to accommodate the injection of 1.1 million metric tons of CO 2 per year over a 20-year period. The injection of CO 2 and the associated pressure buildup in the reservoir is expected to alter the state of stress over the course of the injection. These changes in the initial stress state may affect fault stability and potentially lead to the unintentional creation of hydraulic fractures, which could pose a leakage risk if not contained within the reservoir. Assessing these risks is critical to making informed decisions about the characterization, management of the injection operation, and monitoring of the storage site. The data required by SOSAT for the geomechanical assessment of the FutureGen 2.0 site were identified, and the methodology proposed in SOSAT was followed to evaluate the probability of reactivating critically oriented faults or potentially creating hydraulic fractures in the reservoir. The results of the geomechanical analysis performed using the SOSAT led to the following conclusions. 1. The probability distribution of the state of stress indicates significant uncertainties in the magnitude of the maximum horizontal stress S Hmax , while the minimum horizontal stress S hmin is well constrained by the stress measurements conducted during the characterization efforts at the storage site. This uncertainty in the magnitude of S Hmax is a common challenge and has significant implications for geomechanical risk at sites like FutureGen 2.0 where a strike-slip tectonic regime exists. 2. The probability that the Mount Simon reservoir was initially critically stressed is relatively high—25%. When the pore pressure increases to the maximum allowable pressure permitted under the Underground Injection Control Class VI regulation of the FutureGen 2.0 project, the risk of shear failure approaches a probability of 43%. These relatively high probabilities reflect the current state of information about the geomechanical conditions in this part of the Illinois Basin. For future operations in this basin this should be a high characterization priority because it could significantly lower the risk of operations. 3. Based on the maximum injection pressure allowed in the UIC Class VI, the risk of unintentional hydraulic fracturing is limited. The risk of shear failure as determined by SOSAT is based on a very conservative approach assuming that critically oriented faults exist in the subsurface. While no faults have been formally identified at the FutureGen 2.0 site, the results obtained with SOSAT using the FutureGen 2.0 data set highlight the importance of integrating uncertainties in critical parameters to quantify geomechanical risks in a defensible way. Should SOSAT have been available at the time the characterization activities were being planned, more characterization efforts would have been implemented to reduce the uncertainties on the magnitude of the maximum horizontal stress, and to dismiss with confidence the potential existence of a critically-oriented fault in the reservoir (e.g., 3D seismic survey).

54 ENVIRONMENTAL SCIENCES↗

Refine your search to explore more results.