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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Fusion Imaging Reduces Radiation and Contrast Medium Exposure During Endovascular Revascularization of Iliac Steno-Occlusive Disease

Introduction: To evaluate feasibility, safety and efficacy of fusion imaging in order to guide endovascular revascularization of iliac steno-occlusive disease. Materials and Methods: Retrospectively, we identified twenty-six patients (20 male, mean age 63 ± 8y; Rutherford II-V) who underwent revascularization of a chronic total occlusion (n = 6; 23%) or severe stenosis (n = 20; 77%) of the common and/or external iliac artery. Median lesion length was 33 mm (IQR 20–60). In one group of patients (NEW; n = 11), fusion imaging with 2-D/3-D registration was used to guide revascularization. No baseline digital subtraction angiography (DSA) had been acquired in these patients. In another group of patients (OLD; n = 15), no fusion imaging had been utilized and at least one DSA run had been performed to guide the procedure. In both groups, final DSA of the treated lesions was performed. Number of DSA runs, radiation and contrast medium exposure, technical success (residual stenosis < 30%) and complications were analyzed. Results: Median DSA runs needed in OLD for guidance were n = 2 (IQR 2–3) and in NEW n = 0 (IQR 0–0; p = 0.001). Compared to OLD, median dose area product (DAP) was reduced by 17,118 mGy*cm{sup 2} (IQR 10,407–23,614; p = 0.016) if fusion imaging guidance had been used (NEW). Based on the median DAP of the final angiogram in NEW, median DAP reduction was 6007 mGy*cm{sup 2} (IQR 5012–16,105; p = 0.1). Median total contrast medium volume injected in NEW was 45 ml (IQR 30–90) and in OLD 120 ml (IQR 100–140; p = 0.001). Technical success was 100% for both groups. In 1/27 patients (3.7%) a minor complication (embolism) occurred. Conclusion: Fusion imaging proved to be feasible as well as safe and significantly reduces radiation and contrast medium exposure during endovascular revascularization of iliac steno-occlusive disease.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Innovations in science and scenarios for assessment

Scenarios for the Third National Climate Assessment (NCA3) were produced for physical climate and sea level rise with substantial input from disciplinary and regional experts. These scenarios underwent extensive review and were published as NOAA Technical Reports. For land use/cover and socioeconomic conditions, scenarios already developed by other agencies were specified for use in the NCA3. Efforts to enhance participatory scenario planning as an assessment activity were pursued, but with limited success. Issues and challenges included the timing of availability of scenarios, the need for guidance in use of scenarios, the need for approaches to nest information within multiple scales and sectors, engagement and collaboration of end users in scenario development, and development of integrated scenarios. Future assessments would benefit from an earlier start to scenarios development, the provision of training in addition to guidance documents, new and flexible approaches for nesting information, ongoing engagement and advice from both scientific and end user communities, and the development of consistent and integrated scenarios.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Furthering Precision in Sentinel Node Navigational Surgery for Oral Cancer: a Novel Triple Targeting System

To describe an innovative sentinel lymph node (SLN) guidance approach using a radionuclide tracer, 3D augmented reality-guided imaging, and near infrared (NIR) fluorescence over-lay imaging with hand-held probes to optimize accuracy, efficiency, and precise navigation for sentinel node (SN) localization in head and neck cancer. In a cT1N0M0 squamous cell carcinoma of the tongue, pre-operative radionuclide lymphoscintigraphy was performed with a sentinel node-specific radiolabeled tracer. Intraoperatively, a 3D hand-held augmented reality (AR) scanning SPECT probe assessed concordance of the SN with pre-operative SPECT-CT images. The real-time optical video was linked to the SPECT-CT images for added precision. Final guidance to the SN was performed using ICG fluorescence imaging. Dynamic and SPECT-CT showed bilateral lymphatic drainage from the tumor. The 3D hand-held AR SPECT probe SN localization was concordant with pre-operative imaging. The optical video successfully demonstrated the lymphatic drainage in real-time through a unique overlay fluorescence image. The ICG localized to the same nodes identified by both the SPECT-CT and hand-held SPECT images. The use of dual radiation and fluorescence tracers improved SN detection, especially for SN close to the injection site. The hand-held probes allowed the surgeon to dissect continuously, without needing to change tools. The combination of augmented reality, nuclear medicine, and over-lay fluorescence imaging allowed greater accuracy for matching the preoperative imaging with intraoperative identification and precisely guiding the dissection. This method uniquely permitted the surgeon to efficiently dissect the SN with accurate visualization and optimal precision.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

The Role of Multimodality Imaging in Transcatheter Aortic Valve Replacement

Purpose of Review: Multimodality imaging is integral for diagnosis, procedural guidance, and follow-up of patients undergoing transcatheter aortic valve replacement (TAVR). In this review, we provide an overview of the role of each imaging modality and highlight technical considerations and pitfalls. We also address current controversies and new developments in the field. Recent Findings: Echocardiography remains the primary imaging modality for diagnosis of aortic stenosis and intraprocedural guidance for TAVR, but computed tomography (CT) imaging has supplanted echocardiography for annular sizing and access site evaluation. Magnetic resonance imaging (MRI) shows promise in targeted patient populations. Refined parameters and guidelines for valve sizing and paravalvular regurgitation have sought to standardize these complex assessments. Summary: Multimodality imaging remains critical to the success of TAVR, but its role has evolved over time. Understanding the applications, strengths, and limitations of each imaging modality is a crucial skill for the modern structural imager.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2020

A new algae technical standards focus group: Summarizing and guiding the algae state of the art

The value proposition of algae technical metrics was the subject of a recent, industry-led, Focus Group interactive discussion. The interactive platform allowed for real time capturing and priority ranking of the topics that are deemed critical challenges for a future successful algae-based bioeconomy. This work ultimately sets the stage for providing guidance, methods, and standard reference materials tailored to respective algae industry segments for the cultivation, processing and marketing of high-quality and safe algae-based products. The group solicits input from the broader algae community on the value proposition and presents a case here to build a consensus around algae-specific metrics. The value proposition of technical standards to the industry is that guidance obtained through these collaborations builds producers' and consumers' trust that algae and algae-derived products are safe, reliable, and may allow for expanded market access, and increased competitiveness and international trade.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Comprehensive Analysis of Model Parameter Uncertainty Influence on Evaluation of HVAC Operation to Mitigate Indoor Virus: A Case Study for an Office Building in a Cold and Dry Climate

Simulation-based studies of HVAC operation to mitigate indoor virus have been conducted to understand tradeoffs between indoor air quality (IAQ) and energy consumption. However, the influence of model parameter uncertainty in these studies has not been systematically quantified, which is critical when providing guidance to building operators. To address this gap, we identify 20 model parameters for a typical medium office building system in a cold and dry climate that can influence IAQ and energy consumption for indoor virus scenarios. Next, the distributions of the parameter values are estimated from literature and a set of simulation samples for three representative days is generated that simultaneously sample all of the parameters from their distributions. Two HVAC virus mitigation strategies are studied: increased filtration using MERV 13 filters and increased ventilation, via supply of 100% outdoor air into buildings. The model parameter uncertainty leads to significant variability in the results, particularly for the IAQ because of the highly uncertain virus generation rate. Use of 100% outdoor air can be beneficial for some uncertain scenarios on the hot day, but shows less IAQ improvement and/or significant energy increases on the other days. The virus removal efficiency and pressure drop of the HVAC filter, fan efficiency, and internal heat gain are the most important parameters to determining the tradeoffs of the two strategies. Our results demonstrate how this model parameter uncertainty analysis methodology can provide practical guidance to building operators.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Experimental determination of solubilities of magnesium borates: Solubility constants of boracite [Mg 3 B 7 O 13 Cl(cr)] and aksaite [MgB 6 O 7 (OH) 6 ·2H 2 O(cr)]

In this work, solubility measurements regarding boracite [Mg 3 B 7 O 13 Cl(cr)] and aksaite [MgB 6 O 7 (OH) 6 ·2H 2 O(cr)] from the direction of supersaturation were conducted at 22.5 ± 0.5 °C. The equilibrium constant (log 10 K 0 ) for boracite in terms of the following reaction, Mg 3 B 7 O 13 Cl(cr) + 15H 2 O(l) ⇌ 3Mg 2+ + 7B(OH) 4 – + Cl – + 2H + is determined as -29.49 ± 0.39 (2σ) in this study. The equilibrium constant for aksaite according to the following reaction, MgB 6 O 7 (OH) 6 •2H 2 O(cr) + 9H 2 O(l) ⇌ Mg 2+ + 6B(OH) 4 – + 4H + is determined as -44.41 ± 0.41 (2σ) in this work. This work recommends a set of thermodynamic properties for aksaite at 25 °C and 1 bar as follows: ΔH$0\atop{f}$ =-6063.70 ± 4.85 kJ·mol -1 , ΔG =-5492.55 ± 2.32 kJ·mol -1 , and S 0 = 344.62 ± 1.85 J·mol -1 ·K -1 . Among them, ΔG$0\atop{f}$ is derived from the equilibrium constant for aksaite determined by this study; ΔH$0\atop{f}$ is from the literature, determined by calorimetry; and S 0 is computed in the present work from ΔG$0\atop{f}$ and ΔH$0\atop{f}$. This investigation also recommends a set of thermodynamic properties for boracite at 25 °C and 1 bar as follows: ΔH$0\atop{f}$ =-6575.02 ± 2.25 kJ·mol -1 , ΔG$0\atop{f}$ =-6178.35 ± 2.25 kJ·mol -1 , and S 0 = 253.6 ± 0.5 J·mol -1 ·K -1 . Among them, ΔG$0\atop{f}$ is derived from the equilibrium constant for boracite determined by this study; S 0 is from the literature, determined by calorimetry; and ΔH$0\atop{f}$ is computed in this work from ΔG$0\atop{f}$ and S 0 . The thermodynamic properties determined in this study can find applications in many fields. For instance, in the field of material science, boracite has many useful properties including ferroelectric and ferroelastic properties. The equilibrium constant of boracite determined in this work will provide guidance for economic synthesis of boracite in an aqueous medium. Similarly, in the field of nuclear waste management, iodide boracite [Mg 3 B 7 O 13 I(cr)] is proposed as a waste form for radioactive 129 I. Therefore, the solubility constant for chloride boracite [Mg 3 B 7 O 13 Cl(cr)] will provide the guidance for the performance of iodide boracite in geological repositories. Boracite/aksaite themselves in geological repositories in salt formations may be solubility-controlling phase(s) for borate. Finally, solubility constants of boracite and aksaite will enable researchers to predict borate concentrations in equilibrium with boracite/aksaite in salt formations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

A computational fluid dynamics modeling study of guide walls for downstream fish passage

A partial-depth, impermeable guidance structure (or guide wall) for downstream fish passage is typically constructed as a series of panels attached to a floating boom and anchored across a water body (e.g. river channel, reservoir, or power canal). The downstream terminus of the wall is generally located nearby to a fish bypass structure. If guidance is successful, the fish will avoid entrainment in a dangerous intake structure (i.e. turbine intakes) while passing from the headpond to the tailwater of a hydroelectric facility through a safer passage route (i.e. the bypass). The goal of this study is to determine the combination of guide wall design parameters that will most likely increase the chance of surface-oriented fish being successfully guided to the bypass. To evaluate the flow field immediately upstream of a guide wall, a parameterized computational fluid dynamics model of an idealized power canal was constructed in © ANSYS Fluent v 14.5 (ANSYS Inc., 2012). The design parameters investigated were the angle and depth of the guide wall and the average approach velocity in the power canal. Results call attention to the importance of the downward to sweeping flow ratio and demonstrate how a change in guide wall depth and angle can affect this important hydraulic cue to out-migrating fish. The key findings indicate that a guide wall set at a small angle (15° is the minimum in this study) and deep enough such that sweeping flow dominant conditions prevail within the expected vertical distribution of fish approaching the structure will produce hydraulic conditions that are more likely to result in effective passage.

42 ENGINEERING↗
DOE OSTI2013

Strategic environmental assessment for sustainability: A review of a decade of academic research

This paper examines the strategic environmental assessment (SEA)–sustainability relationship over the past decade, from 2000 to 2010, focusing in particular on the incorporation of sustainability in SEA. A total of 86 papers from the academic literature containing the terms ‘sustainability’ or ‘sustainable development’ and ‘strategic environmental assessment’ were identified and reviewed. Several common themes emerged by which SEA can support sustainability, including providing a framework to support decision making for sustainability; setting sustainability objectives, ensuring the consideration of ‘more sustainable’ alternatives, and integrating sustainability criteria in PPP development; and promoting sustainability outcomes through tiering and institutional learning. At the same time, our review identified many underlying barriers that challenge SEA for sustainability, including the variable interpretations of the scope of sustainability in SEA; the limited use of assessment criteria directly linked to sustainability objectives; and challenges for decision-makers in operationalizing sustainability in SEA and adapting PPP development decision-making processes to include sustainability issues. To advance SEA for sustainability there is a need to better define the scope of sustainability in SEA; clarify how to operationalize the different approaches to sustainability in SEA, as opposed to simply describing those approaches; provide guidance on how to operationalize broad sustainability goals through assessment criteria in SEA; and understand better how to facilitate institutional learning regarding sustainability through SEA application. -- Highlights: ► There is significant potential for SEA to support sustainability in PPP development. ► However, there are still many barriers in place that challenge SEA for sustainability. ► The scope and approaches to sustainability in SEA must be better defined and described. ► Guidance is needed to link impact assessment criteria to sustainability objectives. ► Focus on how to facilitate institutional learning regarding sustainability is required.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

A protocol for lifetime energy and environmental impact assessment of building insulation materials

This article describes a proposed protocol that is intended to provide a comprehensive list of factors to be considered in evaluating the direct and indirect environmental impacts of building insulation materials, as well as detailed descriptions of standardized calculation methodologies to determine those impacts. The energy and environmental impacts of insulation materials can generally be divided into two categories: (1) direct impact due to the embodied energy of the insulation materials and other factors and (2) indirect or environmental impacts avoided as a result of reduced building energy use due to addition of insulation. Standards and product category rules exist, which provide guidelines about the life cycle assessment (LCA) of materials, including building insulation products. However, critical reviews have suggested that these standards fail to provide complete guidance to LCA studies and suffer from ambiguities regarding the determination of the environmental impacts of building insulation and other products. The focus of the assessment protocol described here is to identify all factors that contribute to the total energy and environmental impacts of different building insulation products and, more importantly, provide standardized determination methods that will allow comparison of different insulation material types. Further, the intent is not to replace current LCA standards but to provide a well-defined, easy-to-use comparison method for insulation materials using existing LCA guidelines. - Highlights: • We proposed a protocol to evaluate the environmental impacts of insulation materials. • The protocol considers all life cycle stages of an insulation material. • Both the direct environmental impacts and the indirect impacts are defined. • Standardized calculation methods for the ‘avoided operational energy’ is defined. • Standardized calculation methods for the ‘avoided environmental impact’ is defined.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Assessing corporate project impacts in changeable contexts: A human rights perspective

Project-level impact assessment was originally conceived as a snapshot taken in advance of project implementation, contrasting current conditions with a likely future scenario involving a variety of predicted impacts. Current best practice guidance has encouraged a shift towards longitudinal assessments from the pre-project stage through the implementation and operating phases. Experience and study show, however, that assessment of infrastructure-intensive projects rarely endures past the project's construction phase. Negative consequences for environmental, social and health outcomes have been documented. Such consequences clarify the pressing need for longitudinal assessment in each of these domains, with human rights impact assessment (HRIA) as an umbrella over, and critical augmentation of, environmental, social and health assessments. Project impacts on human rights are more closely linked to political, economic and other factors beyond immediate effects of a company's policy and action throughout the project lifecycle. Delineating these processes requires an adequate framework, with strategies for collecting longitudinal data, protocols that provide core information for impact assessment and guidance for adaptive mitigation strategies as project-related effects change over time. This article presents general principles for the design and implementation of sustained, longitudinal HRIA, based on experience assessing and responding to human rights impact in a uranium mining project in Malawi. The case study demonstrates the value of longitudinal assessment both for limiting corporate risk and improving human welfare. - Graphical abstract: Assessing changes in human rights condition as affected by both project and context, over time. - Highlights: • Corporate capital projects affect human rights in myriad ways. • Ongoing, longitudinal impact assessment techniques are needed. • We present an approach for conducting longitudinal human rights impact assessment. • Our methodology allows distinguishing corporate impacts from contextual changes. • Promptly observing context changes and impacts enables companies to react nimbly.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Assessment of health risks of policies

The assessment of health risks of policies is an inevitable, although challenging prerequisite for the inclusion of health considerations in political decision making. The aim of our project was to develop a so far missing methodological guide for the assessment of the complex impact structure of policies. The guide was developed in a consensual way based on experiences gathered during the assessment of specific national policies selected by the partners of an EU project. Methodological considerations were discussed and summarized in workshops and pilot tested on the EU Health Strategy for finalization. The combined tool, which includes a textual guidance and a checklist, follows the top-down approach, that is, it guides the analysis of causal chains from the policy through related health determinants and risk factors to health outcomes. The tool discusses the most important practical issues of assessment by impact level. It emphasises the transparent identification and prioritisation of factors, the consideration of the feasibility of exposure and outcome assessment with special focus on quantification. The developed guide provides useful methodological instructions for the comprehensive assessment of health risks of policies that can be effectively used in the health impact assessment of policy proposals. - Highlights: • Methodological guide for the assessment of health risks of policies is introduced. • The tool is developed based on the experiences from several case studies. • The combined tool consists of a textual guidance and a checklist. • The top-down approach is followed through the levels of the full impact chain. • The guide provides assistance for the health impact assessment of policy proposals.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Is the ecosystem service concept improving impact assessment? Evidence from recent international practice

Considering ecosystem services (ES) could foster innovation and improve environmental and social impact assessment (ESIA) practice, but is the potential being fulfilled? In order to investigate how ES have been treated in recent international practice, three questions are asked: (i) were the tasks of an ES analysis carried out? (ii) how is such analysis integrated with other analysis presented in the ESIA? (iii) does ES analysis result in additional or improved mitigation or enhancement measures? These research questions were unfolded into 15 auxiliary questions for reviewing five ESIA reports prepared for mining, hydroelectric and transportation infrastructure projects in Africa, Asia and South America. All cases incorporated ES into ESIA to meet a requirement of the International Finance Corporation's Performance Standards on Environmental and Social Sustainability. It was found that: (i) in only three cases most tasks recommended by current guidance were adopted (ii) all reports feature a dedicated ES chapter or section, but in three of them no evidence was found that the ES analysis was integrated within impact assessment (iii) in the two ESIAs that followed guidance, ES analysis resulted in specific mitigation measures. Few evidence was found that the ES concept is improving current ESIA practice. Key challenges are: (i) integrating ES analysis in such a way that it does not duplicate other analysis; (ii) adequately characterizing the beneficiaries of ES; and (iii) quantifying ES supply for impact prediction. - Highlights: • Incorporating ecosystem services analysis in impact assessment can improve results. • Additional impacts and mitigation were identified. • Challenges include developing appropriate indicators for impact prediction. • A key challenge is integrating the concept in such a way that it does not duplicate other analysis.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Stakeholder perceptions of Environmental Management Plans as an environmental protection tool for major developments in the UK

Insufficient implementation and the lack of legislative requirements for follow-up measures following the approval of projects are consistently highlighted as major shortcomings of Environmental Impact Assessment (EIA). Although adopted over 15 years ago by the World Bank, Environmental Management Plans (EMPs) were only semi-formalised in the UK in 2008 and arguably provide a continuous link or ‘bridge’ between the EIA process pre-consent and an Environmental Management System (EMS) post-consent. Drawing on twenty-one semi-structured interviews with stakeholders and thematic analysis of their responses, and a broad-scale practitioner survey, this study aimed to assess the effectiveness of EMPs as an environmental protection tool across the project lifecycle for major developments. The findings revealed a mixed picture of EMP effectiveness in practice, with EMPs only partially fulfilling a bridging role between EIA and EMS. There is no ‘gold standard’ terminology for EMPs, all having slightly different uses, thus presenting different focuses to different stakeholders and further enhancing variation in practice. For many stakeholders, the effectiveness was simply not known, due to the lack of communication and follow-up that still exists. EMP–EMS linkages were shown to be effective from the developer's perspective when a single organisation has involvement across all project phases, though weaknesses occur when multiple parties are involved. Among other stakeholders, knowledge varied significantly; whilst some were in agreement that the linkages worked, many were unaware of the connections and thought of them as two quite separate tools. Stakeholders advocated for the need to make EMPs a legal requirement; for improved communication between stakeholders during EMP implementation and increased documentation of project outcomes; and for EMPs to be consistently written by environmental professionals. Furthermore, weak links in the current process may be improved by providing detailed guidance for organisations on the potential for EMP–EMS linkages, with the additional aim of encouraging stakeholders to broaden their current specialist knowledge on environmental protection tools. - Highlights: • We assessed the effectiveness of Environmental Management Plans (EMPs) for major developments, focusing on delivery of mitigation and monitoring. • EIA and Environmental Management Systems (EMS) post-consent are weakly linked. • The use of EMPs varies significantly in practise, partly due to the range of terminology used. • Linkages are hampered by poor communication and follow-up • More detailed guidance on how EMPs can successfully link with EMS is required.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

An experimental study on fish attraction using a fish barge model

Fish-collection and transportation systems (FCTS) have been introduced and applied as innovative approaches to facilitate fish passage in China for several years. The efficacy of FCTSs depends directly on the efficiency of the fish-guidance measures employed. In this study, the effects of three parameters—water flow, artificial lighting, and bubble curtains—on the attraction of mosquitofish ( Gambusia affinis ) was investigated using a fish barge model in a large pond. The experiment was conducted in two steps. First, a univariate experiment was performed, and then, a multivariate experiment using an orthogonal design was performed. Four different colors of light were tested: 1) yellow light (570 nm), 2) blue light (460 nm), 3) warm white light (3000 K), and 4) a weak light control group, whose illuminance belongs to the interval 0.001 lx to 0.3 lx. Supplementing water flow within the barge decreased the number of attracted fish (i.e., the number of the targeted fish species that appeared within 1.5m of the barge model’s entrance) but increased the fish-collection ratio of the fish-collecting platform (i.e., the ratio of the number of attracted fish to the number of collected fish). Warm white light was shown to be significantly effective in attracting fish, while no obvious effect was observed in terms of the fish collection ratio. The bubble curtain exhibited excellent fish-attraction efficacies, but also had no significant effect on the attraction and collection efficacy of the fish-collecting platform. During the day, the optimal combination for fish attraction was to have no water flow with a bubble curtain, while the optimal combination for fish collection was to have no water flow and no bubble curtain. During the night, the optimal combination for fish attraction was to have no water flow, no bubble curtain, and a warm white light, while the optimal combination for fish collection was to have water flow, no bubble curtain, and a weak light. This study tested the combined efficacies of various fish-guidance measures on a fish-collecting platform, thus providing experimental support for optimizing various fish-attraction measures and the application of these measures in FCTS projects.

Lin, Chenyu↗
DOE OSTI2026

Modeling and Experimental Validation of a Direct-Contact Counter-Flow Fluidized Bed Heat Exchanger for Thermal Energy Storage (TES) Applications

Particle-based thermal energy storage (TES) systems are an emerging energy storage technology. The technological advances have reduced costs, making TES more competitive and reliable in the marketplace but an efficient and reliable operation is heavily dependent on coherent heat transfer between air to particles or vice versa. The particle-based TES technologies provide an intermediate system that can store energy for short (0-10 h), long (10-200 h) and seasonal (> 200 h) timescales. The TES systems store energy by converting electricity to thermal energy; electricity can be directly sourced intermittent generation technologies and/or the grid, helping manage peak loads and other mismatches in supply and demand. The overall efficiency of the TES system depends on the performance of system components (particle storage silos and particle transfer mechanism etc.). The particle heat exchanger is one of the key system components that affects the system efficiency. The pressurized fluidized bed heat exchanger (PFB HX) performance is challenging to predict due to the chaotic behavior of particle and fluid interaction. This research presents a computational study of a novel direct-contact, counter-flow and air-to-particles PFB HX, that contributes in advancing the particle-based long-duration TES technologies. For the current analysis an unsteady Eulerian-Eulerian CFD model was developed and validated against experiments performed at the National Laboratory of the Rockies for two particle sizes (600 ..mu..m and 825 ..mu..m ). Following validation, parametric simulations were conducted to evaluate the effects of interphase drag models (Syamlal-O'Brien and Gidaspow), particle size, bed height and the influence of a frictional-viscosity term on hydrodynamics and heat transfer between the air & particles. The key findings from the analysis are: (1) for the studied operating window Syamlal-O'Brien provides superior agreement with measured gas temperatures (errors generally < 10%) while Gidaspow shows large deviations for the coarse particle case; (2) model predictions are most sensitive in the lower 0.2 m above the air distributor where bubble initiation and local mixing dominate interphase heat transfer; (3) representation of the distributor (number of inlet ports) materially affects predicted local mixing and temperature stratification; and (4) the Eulerian-Eulerian framework reproduces bulk thermal trends but shows regime dependent limitations for coarse particles, motivating mesoscale informed closures for scale-up analysis for future studies. These results provide validated guidance for drag selection and distributor design in particle-based thermal energy storage applications. Collectively, the validated model and parametric results quantify key drivers of PHB-HX performance and provide practical guidance for design and optimization. The results provide confidence in the model predictability and provide a step forward to improve on heat exchange performance. The demonstrated performance and modeling approach support the deployment and further development of this novel PHB-HX concept for robust, particle-based long-duration thermal energy storage systems.

25 ENERGY STORAGE↗
DOE OSTI2019

Risk-based monitoring designs for detecting CO 2 leakage through abandoned wellbores: An application of NRAP’s WLAT and DREAM tools

We report that one suggested approach to managing the risk of geologic CO 2 storage projects is to perform risk-based subsurface monitoring targeting early leak detection. The challenge in risk-based monitoring is that leakage impacts are expected to be small in comparison with the footprint of the stored CO 2 plume and could be at depths ranging from the depth of storage (often ~1 km bgs) up to surficial aquifers. Addressing this challenge requires a multidisciplinary effort capable of characterizing potential subsurface leakage in terms of likelihood, location, magnitude, impacts to overlying aquifers, and uncertainty as well as innovative monitoring technology design and implementation. The National Risk Assessment Partnership (NRAP) was established to develop related risk assessment tools to provide guidance on such assessments. Here we demonstrate the application workflow of two of the NRAP computational tools, WLAT (Wellbore Leakage Analysis Tool) and DREAM (Designs for Risk Evaluation and Management), to a hypothetical CO 2 storage site based on a study area in the Midwestern United States. This workflow shows how CO 2 leakage may be estimated, evaluated, and monitored in terms of risk. Results provide guidance on monitoring configurations and technologies which minimize the time to leak detection, maximize the probability detection, and provide cost considerations.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Intrafraction Bladder Motion in Radiation Therapy Estimated From Pretreatment and Posttreatment Volumetric Imaging

Purpose: The use of image guidance protocols using soft tissue anatomy identification before treatment can reduce interfractional variation. This makes intrafraction clinical target volume (CTV) to planning target volume (PTV) changes more important, including those resulting from intrafraction bladder filling and motion. The purpose of this study was to investigate the required intrafraction margins for soft tissue image guidance from pretreatment and posttreatment volumetric imaging. Methods and Materials: Fifty patients with muscle-invasive bladder cancer (T2-T4) underwent an adaptive radiation therapy protocol using daily pretreatment cone beam computed tomography (CBCT) with weekly posttreatment CBCT. A total of 235 pairs of pretreatment and posttreatment CBCT images were retrospectively contoured by a single radiation oncologist (CBCT-CTV). The maximum bladder displacement was measured according to the patient's bony pelvis movement during treatment, intrafraction bladder filling, and bladder centroid motion. Results: The mean time between pretreatment and posttreatment CBCT was 13 minutes, 52 seconds (range, 7 min 52 sec to 30 min 56 sec). Taking into account patient motion, bladder centroid motion, and bladder filling, the required margins to cover intrafraction changes from pretreatment to posttreatment in the superior, inferior, right, left, anterior, and posterior were 1.25 cm (range, 1.19-1.50 cm), 0.67 cm (range, 0.58-1.12 cm), 0.74 cm (range, 0.59-0.94 cm), 0.73 cm (range, 0.51-1.00 cm), 1.20 cm (range, 0.85-1.32 cm), and 0.86 cm (range, 0.73-0.99), respectively. Small bladders on pretreatment imaging had relatively the largest increase in pretreatment to posttreatment volume. Conclusion: Intrafraction motion of the bladder based on pretreatment and posttreatment bladder imaging can be significant particularly in the anterior and superior directions. Patient motion, bladder centroid motion, and bladder filling all contribute to changes between pretreatment and posttreatment imaging. Asymmetric expansion of CTV to PTV should be considered. Care is required in using image-guided radiation therapy protocols that reduce CTV to PTV margins based only on daily pretreatment soft tissue position.

62 RADIOLOGY AND NUCLEAR MEDICINE↗