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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 1,657 records · Page 92

Practical Challenges and Future Perspectives of All-Solid-State Lithium-Metal Batteries

The fundamental understandings and technological innovations in lithium-ion batteries are essential for delivering high energy density, stable cyclability, and cost-effective energy storages with the growing demands in the applications of electrical vehicles and smart grid. Solid-state electrolytes (SSEs) are more promising than organic liquid electrolyte in terms of excellent safety in developing lithium-metal anode as well as other high-capacity cathode chemistries, such as sulfur and oxygen. Considerable efforts have been made to give birth to the superionic conductors with ionic conductivities higher than 10 –3 S cm –1 at room temperature. Furthermore, the high interfacial impedances from the poor compatibility of SSEs with electrodes limit their practical applications, which are discussed in this review. Furthermore, the recent advances and critical challenges for all-solid-state lithium-metal batteries based on the cathode materials of lithium-intercalation compounds, sulfur, and oxygen are overviewed, and their future developments are also prospected.

25 ENERGY STORAGE↗

Within-host mathematical models of hepatitis B virus infection: Past, present, and future

Mathematical modeling has been instrumental in enhancing our understanding of the viral dynamics of hepatitis B virus (HBV) infection. We give a primer on HBV infection in humans and a brief overview of the development of within-host mathematical models of HBV infection. In the last decade, models have advanced from considering chronic HBV infections under therapy to the pathogenesis of infection. We also summarize estimates of key viral dynamic parameters that have varied greatly among studies, and show that they impact model predictions. Here, future directions for mathematical modeling of HBV infection are proposed to better understand emerging therapies, the HBV life cycle, predicting cure, and the mechanisms involved in the immune response to HBV.

59 BASIC BIOLOGICAL SCIENCES↗

Machine learning in materials research: Developments over the last decade and challenges for the future

The number of studies that apply machine learning (ML) to materials science has been growing at a rate of approximately 1.67 times per year over the past decade. In this review, I examine this growth in various contexts. First, I present an analysis of the most commonly used tools (software, databases, materials science methods, and ML methods) used within papers that apply ML to materials science. The analysis demonstrates that despite the growth of deep learning techniques, the use of classical machine learning is still dominant as a whole. It also demonstrates how new research can effectively build upon past research, particular in the domain of ML models trained on density functional theory calculation data. Next, I present the progression of best scores as a function of time on the matbench materials science benchmark for formation enthalpy prediction. In particular, a dramatic improvement of 7 times reduction in error is obtained when progressing from feature-based methods that use conventional ML (random forest, support vector regression, etc.) to the use of graph neural network techniques. Finally, I provide views on future challenges and opportunities, focusing on data size and complexity, extrapolation, interpretation, access, and relevance.

36 MATERIALS SCIENCE↗

History, present status, and future directions of vanadium alloys for fusion reactors

Since the need for low-activation fusion reactor materials was recognized in the mid-1980s, vanadium alloys have been researched and developed as promising candidates for blanket structural materials. Vanadium alloys are non-ferromagnetic and ductile materials and thus have advantages different from other candidates. However, since vanadium alloys are still at a premature industrial stage, research and development have been carried out not only on issues specific to fusion reactors but also on those related to industrial materials. Blankets using vanadium alloys as structural materials and liquid Li as a tritium breeder and coolant (self-cooled V/Li blankets) have unique characteristics, and research and development of issues specific to V/Li blankets have been conducted in conjunction with the development of vanadium alloys. In this paper, the progress of this research and development is reviewed, and the remaining issues are pointed out. As a result, the future direction of vanadium alloy research and development is discussed, considering recent changes in the environment surrounding fusion energy.

Liquid Li blanket↗

Developing an Integrated History and future of People on Earth (IHOPE)

The challenges of modeling future socio-ecological states numerically suggest that qualitative understanding of system behavior should be further developed. The objective here is to identify and develop general principles of socio-ecological system behavior, supported by empirical evidence drawn from long records of regional environmental change. A few are deduced from historical case studies. But for others, we can take principles (often aphorisms) from theoretical ecology and complexity science and test their validity in the real world by comparison with historical records. Past records not only provide longer timescales than are conventionally available for observations, but also provide a larger array of socio-ecological systems than currently exist. As a basic starting point, here are some principles drawn from the literature and discussions at IHOPE meetings that could be tested (or tested further) with archeological/ palaeoecological/historical records. The bullet points note variants on each theme, further explanations and implications.

54 ENVIRONMENTAL SCIENCES↗

Human–environment interactions in urban green spaces — A systematic review of contemporary issues and prospects for future research

Scientific papers on landscape planning underline the importance of maintaining and developing green spaces because of their multiple environmental and social benefits for city residents. However, a general understanding of contemporary human–environment interaction issues in urban green space is still incomplete and lacks orientation for urban planners. This review examines 219 publications to (1) provide an overview of the current state of research on the relationship between humans and urban green space, (2) group the different research approaches by identifying the main research areas, methods, and target groups, and (3) highlight important future prospects in urban green space research. - Highlights: • Reviewed literature on urban green pins down a dearth of comparative studies. • Case studies in Africa and Russia are marginalized – the Europe and US dominate. • Questionnaires are used as major tool followed by GIS and quantitative approaches. • Developing countries should contribute in building an urban green space agenda. • Interdisciplinary, adaptable and pluralistic approaches can satiate a knowledge gap.

54 ENVIRONMENTAL SCIENCES↗

Improving social impact assessment of protected areas: A review of the literature and directions for future research

Protected areas are the most widely applied policy tool for biodiversity conservation. However, effective management of protected areas is often obstructed by conflicts mainly associated with the social impacts imposed on local communities and other users by their establishment. Despite the importance of these social impacts they remain significantly under-researched. There is now an increasing need to incorporate social impacts in decision making processes by providing accurate estimations and develop ways to forecast their change in the future. Considering the increase of studies identifying this need, the present paper aims to indicate three main directions that will assist in designing effective tools for measuring and most importantly understanding social impacts: a) perceptions on social impacts of individuals who are directly affected by protected areas need to be incorporated in management evaluation techniques in a meaningful and accurate way and be combined with objective measurements of impact; b) understanding the factors determining the actual and perceived levels of social impacts is a key step for the design of effective management frameworks of protected areas and c) social impacts should not be seen as static concepts but should be seen as a dynamic and long-term factor which needs to be incorporated in decision-making processes.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Impacts of COVID-19 related stay-at-home restrictions on residential electricity use and implications for future grid stability

“Stay-at-home” orders and other health precautions enacted during the COVID-19 pandemic have led to substantial changes in residential electricity usage. Here, we conduct a case study to analyze data from 390 apartments in New York City (NYC) to examine the impacts of two key drivers of residential electricity usage: COVID-19 case-loads and the outdoor temperature. We develop a series of regression models to predict two characteristics of residential electricity usage on weekdays: The average occupied apartment’s consumption (kWh) over a 9am-5pm window and the hourly peak demand (Watt) over a 12pm-5pm window. Via a Monte Carlo simulation, we forecast the two usage characteristics under a possible scenario in which stay-at-home orders in NYC, or a similar metropolitan region, coincide with warm summer weather. Under the scenario, the 9am-5pm residential electricity usage on weekdays is predicted to be 15% – 24% higher than under prior, pre-pandemic conditions. This could lead to substantially higher utility costs for residents. Additionally, we predict that the residential hourly peak demand between 12pm and 5pm on weekdays could be 35% – 53% higher than that under pre-pandemic conditions. We conclude that the projected increase in peak demand - which might arise if stay-at-home guidelines coincided with hot weather conditions - could pose grid management challenges, especially for residential feeders. We also note that, if there is a longer lasting shift towards work and study-from-home, utilities will have to rethink load profile considerations. The applications of our predictive models to managing future smart-grid technology are also highlighted.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Recent trends in power system reliability and implications for evaluating future investments in resiliency

Here, this study examines the relationship between annual changes in electricity reliability reported by a large cross-section of U.S. electricity distribution utilities over a period of 13 years and a broad set of potential explanatory variables, including weather and utility characteristics. We find statistically significant correlations between the average number of power interruptions experienced annually and above average wind speeds, precipitation, lightning strikes, and a measure of population density: customers per line mile. We also find significant relationships between the average number of minutes of power interruptions experienced and above average wind speeds, precipitation, cooling degree-days, and one strategy used to mitigate the impacts of severe weather: the amount of underground transmission and distribution line miles. Perhaps most importantly, we find a significant time trend of increasing annual average number of minutes of power interruptions over time—especially when interruptions associated with extreme weather are included. Lastly, the research method described in this analysis can provide a basis for future efforts to project long-term trends in reliability and the associated benefits of strategies to improve grid resiliency to severe weather—both in the U.S. and abroad.

24 POWER TRANSMISSION AND DISTRIBUTION↗

The role of nuclear in China’s energy future: insights from integrated assessment

China, the world’s largest electricity consumer, has strong motivations to deploy nuclear power due to increasing electricity demand and environmental concerns. However, there are social, institutional, and technical barriers to future nuclear expansion. This paper provides an updated assessment of nuclear energy potential in China with analyses at both national and provincial levels and compares results with studies previously conducted. Using an integrated assessment model, this paper considers the interactions among different socioeconomic development pathways, technology options, climate policies, and social/political concerns on inland siting. Among all factors explored, climate policies have the most significant impact on accelerating the deployment of nuclear technologies. Inland siting of nuclear power plants increases total capacity, but the impact is limited without climate policy. The amount of annual nuclear generation across scenarios and studies is unlikely to rise above 11% by 2030 and 30% by 2050 of total Chinese electricity generation. A dramatic increase in total Chinese nuclear energy generating capacity – around 3900 TWh of nuclear generation by 2050 – is only possible in scenarios where China sees electricity demand increase substantially, sticks to and tightens its current Paris Accord commitments, achieves low costs of nuclear technologies, and allows inland siting of nuclear power plants.

China, integrated assesment, Nuclear Power Plants↗

The Future of Sensitivity Analysis: An essential discipline for systems modeling and policy support

Sensitivity analysis (SA) is en route to becoming an integral part of mathematical modeling. The tremendous potential benefits of SA are, however, yet to be fully realized, both for advancing mechanistic and data-driven modeling of human and natural systems, and in support of decision making. In this perspective paper, a multidisciplinary group of researchers and practitioners revisit the current status of SA, and outline research challenges in regard to both theoretical frameworks and their applications to solve real-world problems. Six areas are discussed that warrant further attention, including (1) structuring and standardizing SA as a discipline, (2) realizing the untapped potential of SA for systems modeling, (3) addressing the computational burden of SA, (4) progressing SA in the context of machine learning, (5) clarifying the relationship and role of SA to uncertainty quantification, and (6) evolving the use of SA in support of decision making. An outlook for the future of SA is provided that underlines how SA must underpin a wide variety of activities to better serve science and society.

54 ENVIRONMENTAL SCIENCES↗

Challenges of future high power wireless power transfer for light-duty electric vehicles----technology and risk management

Wireless power transfer is a state-of-the-art technology with the advantage of convenience and flexibility, as well as the capability of enabling fully automated charging. With power transfer levels increasing beyond 100 kW, many technical and risk management challenges emerge. Here, instead of focusing on the progress review of wireless power transfer technology, this paper discusses the future challenges and risks for high power wireless charging for light-duty electric vehicles. Aiming at 200 kW or higher wireless power transfer, we discuss technology and risk management challenges in the area of electromagnetic safety, resonant frequency determination, and cybersecurity risks in detail. As potential solutions to overcome these challenges, the latest technologies with an emphasis on advanced shielding solutions and recent progress on SiC converters from both industrial and academic institutions are reviewed, and some perspectives and propositions are provided.

25 ENERGY STORAGE↗

Future air pollution in the Shared Socio-economic Pathways

Emissions of air pollutants such as sulfur and nitrogen oxides and particulates have significant health impacts as well as effects on natural and anthropogenic ecosystems. These same emissions also can change atmospheric chemistry and the planetary energy balance, thereby impacting global and regional climate. Long-term scenarios for air pollutant emissions are needed as inputs to global climate and chemistry models, and for analysis linking air pollutant impacts across sectors. In this paper we present methodology and results for air pollutant emissions in Shared Socioeconomic Pathways (SSP) scenarios. We first present a set of three air pollution narratives that describe high, central, and low pollution control ambitions over the 21 st century. These narratives are then translated into quantitative guidance for use in integrated assessment models. We provide an overview of pollutant emission trajectories under the SSP scenarios. Pollutant emissions in these scenarios cover a wider range than the scenarios used in previous international climate model comparisons. Furthermore, the SSP scenarios provide the opportunity to access a more comprehensive range of future global and regional air quality outcomes.

54 ENVIRONMENTAL SCIENCES↗

Localized Low-Dose Radiotherapy for Follicular Lymphoma: History, Clinical Results, Mechanisms of Action, and Future Outlooks

The extreme radiosensitivity of indolent lymphomas was reported in the early years of radiotherapy (RT). The efficacy of low-dose total body irradiation (1.5-2 Gy) was particularly demonstrative. Higher doses were considered appropriate for localized disease. The optimal (or conventional) dose of curative RT derived from the early studies was determined to be 30-35 Gy. Nevertheless, in older series addressing the tumoricidal radiation dose in non-Hodgkin's lymphomas, investigators noted that a significant number of 'nodular' lymphomas were controlled with a dose of <22 Gy for >3 years. The idea of reintroducing localized low-dose radiotherapy (LDRT) for indolent non-Hodgkin's lymphomas came from a clinical observation. The first study showing the high efficacy of LDRT (4 Gy in two fractions of 2 Gy within 3 days) in selected patients with chemoresistant, indolent, non-Hodgkin's lymphomas was published in 1994. Since this first report, at least eight series of patients treated with localized LDRT have been published, showing a 55% complete response rate in irradiated sites, with a median duration of 15-42 months. How LDRT induces lymphoma cell death remains partly unknown. However, some important advances have recently been reported. Localized LDRT induces an apoptosis of follicular lymphoma cells. This apoptotic cell death elicits an immune response mediated by macrophages and dendritic cells. Follicular lymphoma is probably an ideal model to explore these mechanisms. This review also discusses the future of LDRT for follicular lymphoma.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Surgical Management of Early-Stage Non-small Cell Lung Carcinoma and the Present and Future Roles of Adjuvant Therapy: A Review for the Radiation Oncologist

We review the evidence for optimal surgical management and adjuvant therapy for patients with stages I and II non-small cell lung cancer (NSCLC) along with factors associated with increased risks of recurrence. Based on the current evidence, we recommend optimal use of mediastinal lymph node dissection, adjuvant chemotherapy, and post-operative radiation therapy, and make suggestions for areas to explore in future prospective randomized clinical trials.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Hepatocellular Carcinoma Radiation Therapy: Review of Evidence and Future Opportunities

Hepatocellular carcinoma (HCC) is a leading cause of global cancer death. Curative therapy is not an option for most patients, often because of underlying liver disease. Experience in radiation therapy (RT) for HCC is rapidly increasing. Conformal RT can deliver tumoricidal doses to focal HCC with low rates of toxicity and sustained local control in HCC unsuitable for other locoregional treatments. Stereotactic body RT and particle therapy have been used with long-term control in early HCC or as a bridge to liver transplant. RT has also been effective in treating HCC with portal venous thrombosis. Patients with impaired liver function and extensive disease are at increased risk of toxicity and recurrence. More research on how to combine RT with other standard and novel therapies is warranted. Randomized trials are also needed before RT will be generally accepted as a treatment option for HCC. This review discusses the current state of the literature and opportunities for future research.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

The Older Adult With Locoregionally Advanced Head and Neck Squamous Cell Carcinoma: Knowledge Gaps and Future Direction in Assessment and Treatment

Older adults with head and neck squamous cell carcinoma (HNSCC) pose unique treatment and supportive care challenges to oncologists and other cancer care providers. The majority of patients with HNSCC present with locoregionally advanced disease, for which combined-modality treatment integrating chemotherapy and radiation therapy is often necessary to maximize tumor control. However, applying these approaches to an older population with concomitant comorbidities and a higher risk of functional impairments remains challenging and is exacerbated by the paucity of studies involving older adults. The purpose of this article is to identify knowledge gaps in the evaluation and management of older adults with HNSCC—particularly those undergoing concurrent chemoradiation therapy—and their caregivers through a review of the literature conducted by clinicians, researchers, and patient advocates. The findings highlight the importance of a geriatric assessment and the therapeutic paradigms and challenges relevant to this population. Furthermore, we identify the need for additional research and interventions related to key supportive care issues that arise during and after treatment in older adults with locoregionally advanced HNSCC. On the basis of our findings, we prioritize these issues to guide future patient-oriented research endeavors to address these knowledge gaps and thus better serve this growing patient population.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Modeling nuclear energy’s future role in decarbonized energy systems

Increased attention has been focused on the potential role of nuclear energy in future electricity markets and energy systems as stakeholders target rapid and deep decarbonization and reductions in fossil fuel use. This paper examines models of electric sector planning and broader energy systems optimization to understand the prospective roles of nuclear energy and other technologies. In this perspective, we survey modeling challenges in this environment, illustrate opportunities to propagate best practices, and highlight insights from the deep decarbonization literature on the range of visions for nuclear energy's role. Nuclear energy deployment is highest with combinations of stringent emissions policies, nuclear cost reductions, and constraints on the deployment of other technologies, which underscores model dimensions related to these areas. New modeling capabilities are needed to adequately address emerging issues, including representing characteristics and applications of nuclear energy in systems models, and to ensure the relevance of models for policy and planning as deeper decarbonization is explored.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗