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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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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Influence of the Vapor Channel in Deep Laser Welding

The physical processes associated with deep welding are analyzed. A two-dimensional numerical model is proposed for the interaction of the laser beam with the medium in the vapor channel. The following processes are considered: heat and mass transfer; absorption and reradiation of the beam’s energy by the plasma; interaction of the plasma with the channel walls; and heat transfer to the cold sample. The model establishes a quantitative relation between the welding conditions and the results of butt welding. That decreases the expenditures in the development of laser-welding processes.

42 ENGINEERING↗
DOE OSTI2011

Mountaineer Commercial Scale Carbon Capture and Storage Project Topical Report: Preliminary Public Design Report

This Preliminary Public Design Report consolidates for public use nonproprietary design information on the Mountaineer Commercial Scale Carbon Capture & Storage project. The report is based on the preliminary design information developed during the Phase I - Project Definition Phase, spanning the time period of February 1, 2010 through September 30, 2011. The report includes descriptions and/or discussions for: (1) DOE's Clean Coal Power Initiative, overall project & Phase I objectives, and the historical evolution of DOE and American Electric Power (AEP) sponsored projects leading to the current project; (2) Alstom's Chilled Ammonia Process (CAP) carbon capture retrofit technology and the carbon storage and monitoring system; (3) AEP's retrofit approach in terms of plant operational and integration philosophy; (4) The process island equipment and balance of plant systems for the CAP technology; (5) The carbon storage system, addressing injection wells, monitoring wells, system monitoring and controls logic philosophy; (6) Overall project estimate that includes the overnight cost estimate, cost escalation for future year expenditures, and major project risks that factored into the development of the risk based contingency; and (7) AEP's decision to suspend further work on the project at the end of Phase I, notwithstanding its assessment that the Alstom CAP technology is ready for commercial demonstration at the intended scale.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2011

The Technical and Economic Feasibility of Siting Synfuels Plants in Wyoming

A comprehensive study has been completed to determine the feasibility of constructing and operating gasification and reforming plants which convert Wyoming fossil resources (coal and natural gas) into the higher value products of power, transportation fuels, and chemical feedstocks, such as ammonia and methanol. Detailed plant designs, simulation models, economic models and well-to-wheel greenhouse gas models were developed, validated by national-level engineering firms, which were used to address the following issues that heretofore have prevented these types of projects from going forward in Wyoming, as much as elsewhere in the United States: 1. Quantification of plant capital and operating expenditures 2. Optimization of plant heat integration 3. Quantification of coal, natural gas, electricity, and water requirements 4. Access to raw materials and markets 5. Requirements for new infrastructure, such as electrical power lines and product pipelines 6. The possible cost-benefit tradeoffs of using natural gas reforming versus coal gasification 7. The extent of labor resources required for plant construction and for permanent operations 8. Options for managing associated CO2 emissions, including capture and uses in enhanced oil recovery and sequestration 9. Options for reducing water requirements such as recovery of the high moisture content in Wyoming coal and use of air coolers rather than cooling towers 10. Permitting requirements 11. Construction, and economic impacts on the local communities This paper will summarize the analysis completed for two major synfuels production pathways, methanol to gasoline and Fischer-Trosph diesel production, using either coal or natural gas as a feedstock.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2012

Benchmarking Soft Costs for PV Systems in the United States (Presentation)

This paper presents results from the first U.S. based data collection effort to quantify non-hardware, business process costs for PV systems at the residential and commercial scales, using a bottom-up approach. Annual expenditure and labor hour productivity data are analyzed to benchmark business process costs in the specific areas of: (1) customer acquisition; (2) permitting, inspection, andinterconnection; (3) labor costs of third party financing; and (4) installation labor.

14 SOLAR ENERGY↗
DOE OSTI2023

Cost‐benefit assessment framework for robotics‐driven inspection of floating offshore wind farms

Abstract Operations and maintenance (O&M) of floating offshore wind farms (FOWFs) poses various challenges in terms of greater distances from the shore, harsher weather conditions, and restricted mobility options. Robotic systems have the potential to automate some parts of the O&M leading to continuous feature‐rich data acquisition, operational efficiency, along with health and safety improvements. There remains a gap in assessing the techno‐economic feasibility of robotics in the FOWF sector. This paper investigates the costs and benefits of incorporating robotics into the O&M of a FOWF. A bottom‐up cost model is used to estimate the costs for a proposed multi‐robot platform (MRP). The MRP houses unmanned aerial vehicle (UAV) and remotely operated vehicle (ROV) to conduct the inspection of specific FOWF components. Emphasis is laid on the most conducive O&M activities for robotization and the associated technical and cost aspects. The simulation is conducted in Windfarm Operations and Maintenance cost‐Benefit Analysis Tool (WOMBAT), where the metrics of incurred operational expenditure (OPEX) and the inspection time are calculated and compared with those of a baseline case consisting of crew transfer vessels, rope‐access technicians, and divers. Results show that the MRP can reduce the inspection time incurred, but this reduction has dependency on the efficacy of the robotic system and the associated parameterization e.g., cost elements and the inspection rates. Conversely, the increased MRP day rate results in a higher annualized OPEX. Residual risk is calculated to assess the net benefit of incorporating the MRP. Furthermore, sensitivity analysis is conducted to find the key parameters influencing the OPEX and the inspection time variation. A key output of this work is a robust and realistic framework which can be used for the cost‐benefit assessment of future MRP systems for specific FOWF activities.

17 WIND ENERGY↗
DOE OSTI2023

Digital Twins for Nuclear Power Plants and Facilities

The nuclear digital twin (DT) is the virtual representation of a nuclear energy system across its lifecycle. The nuclear DT uses real-time information and other data sources to improve the process of design, licensing, construction, security, O&M, decommissioning, and waste disposal. By leveraging the knowledge base and experience from the past 40 years of LWR operation, the nuclear DT is helping to accelerate the development and deployment of advanced nuclear technology in areas of passive safety, new fuel forms, instrumentation, and reactor control. For the currently operating nuclear fleet, DTs are reducing the operational risks, increasing plant availability, increasing energy capability, and reducing electricity production costs. For advanced fission and fusion reactors, DTs are being used to design for passive safety and built-in security-by-design. Rapidly deployable small modular reactor (SMR) and microreactor designs compatible with modular construction techniques and advanced manufacturing will be the new normal, reducing the need for large capital expenditures and compressing construction schedules. In addition, lower operational and maintenance costs will be realized by reducing the complexity of operations, staffing needs, and maintenance-related activities.

Kropaczek, Dave↗
DOE OSTI2016

The Impact of Tunneled Catheters for Ascites and Peritoneal Carcinomatosis on Patient Rehospitalizations

PurposeThe aim of the study is to assess patient outcomes, complications, impact on rehospitalizations, and healthcare costs in patients with malignant ascites treated with tunneled catheters.Materials and MethodsA total of 84 patients with malignant ascites (mean age, 60 years) were treated with tunneled catheters. Patients with peritoneal carcinomatosis and malignant ascites treated with tunneled drain catheter placement over a 3-year period were studied. Overall survival from the time of ascites and catheter placement were stratified by primary cancer and analyzed using the Kaplan–Meier method. Complications were graded by the Common Terminology Criteria for Adverse Events v3.0 (CTCAE). The differences between pre- and post-catheter admissions, hospitalizations, and Emergency Department (ED) visits, as well as related inpatient expenses were compared using paired t tests.ResultsThere were no significant differences in gender, age, or race between different primary cancer subgroups. One patient (1 %) developed bleeding (CTCAE-2). Four patients (5 %) developed local cellulitis (CTCAE-2). Three patients (4 %) had prolonged hospital stay (between 7 and 10 days) to manage ascites-related complications such as abdominal distention, discomfort, or pain. Comparison between pre- and post-catheter hospitalizations showed significantly lower admissions (−1.4/month, p < 0.001), hospital stays (−4.2/month, p = 0.003), and ED visits (−0.9/month, p = 0.002). The pre- and post-catheter treatment health care cost was estimated using MS-DRG IPPS payment system and it demonstrated significant cost savings from decreased inpatient admissions in post-treatment period (−$9535/month, p < 0.001).ConclusionsTunneled catheter treatment of malignant ascites is safe, feasible, well tolerated, and cost effective. Tunneled catheter treatment may play an important role in improving patients’ quality of life and outcomes while controlling health care expenditures.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2020

Bounded motion design in the Earth zonal problem using differential algebra based normal form methods

Establishing long-term relative bounded motion between orbits in perturbed dynamics is a key challenge in astrodynamics to enable cluster flight with minimum propellant expenditure. Herein, we present an approach that allows for the design of long-term relative bounded motion considering a zonal gravitational model. Entire sets of orbits are obtained via high-order Taylor expansions of Poincarè return maps about reference fixed points. The high-order normal form algorithm is used to determine a change in expansion variables of the map into normal form space, in which the phase space behavior is circular and can be easily parameterized by action–angle coordinates. The action–angle representation of the normal form coordinates is then used to parameterize the original Poincarè return map and average it over a full phase space revolution by a path integral along the angle parameterization. As a result, the averaged nodal period and drift in the ascending node are obtained, for which the bounded motion conditions are straightforwardly imposed. Sets of highly accurate bounded orbits are obtained, extending over several thousand kilometers, and valid for decades.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

Fossil resource and energy security dynamics in conventional and carbon-constrained worlds

Fossil resource endowments and the future development of fossil fuel prices are important factors that will critically influence the nature and direction of the global energy system. In this paper we analyze a multi-model ensemble of long-term energy and emissions scenarios that were developed within the framework of the EMF27 integrated assessment model inter-comparison exercise. The diverse nature of these models highlights large uncertainties in the likely development of fossil resource (coal, oil, and natural gas) consumption, trade, and prices over the course of the twenty-first century and under different climate policy frameworks. We explore and explain some of the differences across scenarios and models and compare the scenario results with fossil resource estimates from the literature. A robust finding across the suite of IAMs is that the cumulative fossil fuel consumption foreseen by the models is well within the bounds of estimated recoverable reserves and resources. Hence, fossil resource constraints are, in and of themselves, unlikely to limit future GHG emissions. Our analysis also shows that climate mitigation policies could lead to a major reallocation of financial flows between regions, in terms of expenditures on fossil fuels and carbon, and can help to alleviate near-term energy security concerns via the reductions in oil imports and increases in energy system diversity they will help to motivate.

McCollum, David↗
DOE OSTI2021

On the modeling paradigm of plant root nutrient acquisition

Plant root nutrient acquisition, and to a lesser extent foliar nutrient uptake, maintain plant metabolism and strongly regulate terrestrial biogeochemistry and carbon-climate feedbacks. However, terrestrial biogeochemical models differ in their representations of plant root nutrient acquisition, leading to significantly different, and uncertain, carbon cycle and future climate projections. Here we first review biogeochemical principles and observations relevant to three essential plant root nutrient acquisition mechanisms: activity of nutrient acquiring proteins, maintenance of nutrient stoichiometry, and energy expenditure for these processes. We next examine how these mechanisms are considered in three existing modeling paradigms, and conclude by recommending the capacity-based approach, the need for observations, and necessary modeling developments of plant root nutrient acquisition to improve carbon-climate feedback projections.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Energy cost savings and expected payback for Re-tuning the controls of US Army buildings

The Headquarters Department of the Army (HQDA) sponsored a study to determine the national impact of deploying the Re-tuning™ methodology in 5 buildings types that account for over 40% of the Army’s conditioned building stock. Re-tuning is a systematic process that improves operational efficiency and reduces energy consumption at no- or low-cost through the building automation system (BAS) by correcting operational problems that plague buildings. The study relied on successful demonstration of the re-tuning methodology at 4 pilot US Army installations that informed a holistic effort that included simulating 12 individual re-tuning energy efficiency measures (EEMs) and 6 packages of EEMs in 5 selected Army building prototype models that represent 311 million ft2 (28.9 million m2) of the Army’s conditioned floor space. Both the baseline buildings and the packages were customized to capture the expected outcomes of re-tuning a diverse set of buildings. The study highlighted the benefit of individual re-tuning EEMs and economics of implementing packages of EEMs in applicable Army buildings across 16 climates and 2 building vintages. The average whole-building energy savings ranged from 10.8% to 40.5% by building type, with the company operations facility (COF) building having the highest value proposition from re-tuning. In addition, the study reveals that all large office (LO) buildings in the Army are economical to re-tune. The total modeled cost savings potential for re-tuning the five building types across the US Army is $204/1,000 sf ($220/100 m2), or $64M annually. This cost savings represents 5.6% of all the Army’s energy expenditures.

Fernandez, Nicholas EP↗
DOE OSTI2021

Cross-national analysis of food security drivers: comparing results based on the Food Insecurity Experience Scale and Global Food Security Index

Abstract The second UN Sustainable Development Goal establishes food security as a priority for governments, multilateral organizations, and NGOs. These institutions track national-level food security performance with an array of metrics and weigh intervention options considering the leverage of many possible drivers. We studied the relationships between several candidate drivers and two response variables based on prominent measures of national food security: the 2019 Global Food Security Index (GFSI) and the Food Insecurity Experience Scale’s (FIES) estimate of the percentage of a nation’s population experiencing food security or mild food insecurity (FI ). We compared the contributions of explanatory variables in regressions predicting both response variables, and we further tested the stability of our results to changes in explanatory variable selection and in the countries included in regression model training and testing. At the cross-national level, the quantity and quality of a nation’s agricultural land were not predictive of either food security metric. We found mixed evidence that per-capita cereal production, per-hectare cereal yield, an aggregate governance metric, logistics performance, and extent of paid employment work were predictive of national food security. Household spending as measured by per-capita final consumption expenditure (HFCE) was consistently the strongest driver among those studied, alone explaining a median of 92% and 70% of variation (based on out-of-sample R 2 ) in GFSI and FI , respectively. The relative strength of HFCE as a predictor was observed for both response variables and was independent of the countries used for model training, the transformations applied to the explanatory variables prior to model training, and the variable selection technique used to specify multivariate regressions. The results of this cross-national analysis reinforce previous research supportive of a causal mechanism where, in the absence of exceptional local factors, an increase in income drives increase in food security. However, the strength of this effect varies depending on the countries included in regression model fitting. We demonstrate that using multiple response metrics, repeated random sampling of input data, and iterative variable selection facilitates a convergence of evidence approach to analyzing food security drivers.

42 ENGINEERING↗
DOE OSTI2018

Group purchasing organization design: a clustering approach

Supply chain management is monitoring of activities involved in supply chain, for integrating and coordinating between suppliers, manufacturing, inventory and transportation both within and among members. The ultimate aim of supply chains is to reduce costs and increase market coverage. Procuring and purchasing requested items in a timely manner are the two most important issues for supply chain stockholders. Group purchasing is one of the purchasing strategies in supply chains. It offers great potential by ordering large volumes to decrease expenses which can increase services to customers. A clustering optimization approach is employed to model group purchasing for a set of pharmacies in the field of healthcare. The proposed model determines a cooperation strategy based on factors such as distance between pharmacies and procurement expenditure in this network. Moreover, the proposed multi-objective group purchasing model is optimized using both goal programming and non-dominated sorting genetic algorithm. To illustrate the application of the proposed model, designing a purchasing group organization for Chalus city pharmacies is investigated. Purchasing groups are established in the way that sum of pharmacies ordering quantity has been located in the second or the third level of discount rate. Thus, the results show that GPOs can take the advantage of this cooperation.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2026

A time-parallel method for scalable heat transfer simulations of additive manufacturing

Here, a major challenge in simulating the thermal behavior in additive manufacturing processes is the disparate length and time scales between transport phenomena occurring in the melt pool and the component. A common simulation approach relies on spatial decomposition for parallel computing, but due to the nature of heat transfer in AM, where most of the computational expenditure is localized near the melt pool, the computational speedup from spatial parallelization saturates quickly. Therefore, additional parallelism by means of time-domain decomposition is needed to fully take advantage of high-performance computing (HPC) resources. This work introduces a time-parallel method to improve the computational scalability of additive manufacturing simulations on HPC systems, while maintaining high temporal resolution of heat transfer near the melt pool. The method, inspired by the nonlinear paraexp formalism, performs an iterative superposition of nonlinear solutions to the initial value problem, integrating the heat equation across overlapping time-parallel intervals. For a single layer of the NIST AMB2018–01 L7 benchmark problem, the method achieves a 38.51x speedup in wall-clock time with a maximum error in the global temperature solution of 0.99%. This reduces the total solution time from 196.72 min to 5.11 min on 128 nodes of the ORNL Frontier supercomputer. The tradeoff between accuracy and total wall-clock time is investigated and recommendations for time-parallel deployment for AM problems are made.

Additive manufacturing↗
DOE OSTI2021

Achieving high ethylene yield in non-oxidative ethane dehydrogenation

Steam cracking of ethane, a non-catalytic thermochemical process, remains the dominant means of ethylene production. The severe reaction conditions and energy expenditure involved in this process incentivize the search for alternative reaction pathways and reactor designs which maximize ethylene yield while minimizing cost and energy input. Herein, we report a comparison of catalytic and non-catalytic non-oxidative dehydrogenation of ethane. We achieve ethylene yields as high as 67 % with an open tube quartz reactor without the use of a catalyst at residence times ~4 s. The open tube reactor design promotes simplicity, low cost, and negligible coke formation. Pristine quartz tubes were most effective, since coke formation was detected when defects were introduced by scratching the surface of the quartz. Surprisingly, the addition of solids to the quartz tube, such as quartz sand, alumina powder, or even Pt-based intermetallic catalysts, led to lower ethylene yield. Pt alloy catalysts are effective at lower temperatures, such as at 575 °C, but conversion is limited due to thermodynamic constraints. When operated at industrially relevant temperatures, such as 700 °C and above, these catalysts were not stable in our tests, causing ethylene yield to drop below that of the open tube. Furthermore, these results suggest that future research on non-oxidative dehydrogenation should be directed at optimizing reactor designs to improve the conversion of ethane to ethylene, since this approach shows promise for decentralized production of ethylene from natural gas deposits.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Power-traffic coordinated operation for bi-peak shaving and bi-ramp smoothing – A hierarchical data-driven approach

The power distribution system and urban transportation system are two networked system bare their own operation constraints, such peak load in power systems and traffic congestion in transportation system. With the increasing number of electrical vehicles and charging/discharging stations, two systems are become tightly coupled. However, to optimize the two systems target using electrical vehicles as decision control variables cannot be easily solved using a uniformed optimization frame work. Thus we propose a hierarchical optimization approach to address this problem, which consists of a higher and a lower level. In the higher level, the power distribution system and urban transportation system are treated together to minimize the social cost. Meanwhile, the electrical vehicles and the charging/discharging stations are treated as customers to minimize their own expenditures. Then, an equilibrium is designed to determine the optimal charging/discharging price. In the lower level, the models of power distribution system and urban transportation system are developed to provide a detailed analysis. Specifically, in power distribution system, the three-phase unbalanced optimal power flow problem is relaxed with the semidefinite relaxation programming, and solved with alternating direction method of multiplier. A dynamic user equilibrium problem is formulated for the urban transportation system. For electrical vehicles, the state of charge is considered to optimize the charging/discharging schedule and reduce the impacts of power distribution systems. We conducted the simulation and numerical analysis using the IEEE 8500-bus distribution system and the Sioux Falls system with about 10,000 cars. The results demonstrate the feasibility and effectiveness of the proposed approach.

24 POWER TRANSMISSION AND DISTRIBUTION↗