Future Use Scenarios Research Articles

Avoiding fusion plasma tearing instability with deep reinforcement learning

For stable and efficient fusion energy production using a tokamak reactor, it is essential to maintain a high-pressure hydrogenic plasma without plasma disruption. Therefore, it is necessary to actively control the tokamak based on the observed plasma state, to manoeuvre high-pressure plasma while avoiding tearing instability, the leading cause of disruptions. This presents an obstacle-avoidance problem for which artificial intelligence based on reinforcement learning has recently shown remarkable performance1–4. However, the obstacle here, the tearing instability, is difficult to forecast and is highly prone to terminating plasma operations, especially in the ITER baseline scenario. Previously, we developed a multimodal dynamic model that estimates the likelihood of future tearing instability based on signals from multiple diagnostics and actuators5. Here we harness this dynamic model as a training environment for reinforcement-learning artificial intelligence, facilitating automated instability prevention. We demonstrate artificial intelligence control to lower the possibility of disruptive tearing instabilities in DIII-D6, the largest magnetic fusion facility in the United States. The controller maintained the tearing likelihood under a given threshold, even under relatively unfavourable conditions of low safety factor and low torque. In particular, it allowed the plasma to actively track the stable path within the time-varying operational space while maintaining H-mode performance, which was challenging with traditional preprogrammed control. This controller paves the path to developing stable high-performance operational scenarios for future use in ITER.

Developing an immersive virtual reality medication administration scenario using the nominal group technique

AimThis paper aims to describe how the Nominal Group Technique was applied to obtain focused content to develop medication administration error scenarios for future use to educate practicing RNs with immersive virtual reality simulation. BackgroundIn the United States, medication errors account for up to $46 million in daily loss to hospital operational budgets. Each phase of prescribing, dispensing, administration, monitoring, and reconciliation is crucial in reducing potentially life-threatening outcomes associated with medication errors. Registered Nurses are responsible for safely administering diverse classifications of medications to patients in various healthcare settings. However, human and system factors can contribute to the exposure of hospitalized patients to a medication error. Virtual reality simulation-based education can be a methodology to educate practicing Registered Nurses on safe medication practices. DesignA Nominal Group Technique process was used to generate consensus from participating Registered Nurses on human and system factors that can contribute to medication administration errors. MethodsThe process consisted of (a) preparation, (b) running the group with an introduction of the subject, (c) generation of ideas, (d) listing of ideas, (e) discussion of ideas, (f) ranking of top ideas, (g) voting on top ideas, (h) discussion of the vote outcome, and (i) re-ranking and rating the top items. Human and system factor idea items encompassed medication errors during ordering, prescribing, or administering medications. Both novice and experienced Registered Nurses rank-ordered these factors as those most likely to encounter or which would most likely occur during one working shift. ResultsDescriptive statistics of frequencies and percentages were used to analyze the findings when grouped by human and system factor categories. Non-parametric testing with a Kruskal-Wallis test was conducted to compare the human and system factors by categories and years of Registered Nurse experience. Findings revealed that the factors of Time Management: getting behind, hurried, urgent (KW-H 11.2, df 4, p = .025) and Right Medication: medications have similar look and sound-alike names (KW-H 11.1, df 4, p = .025) impacted safe medication administration for both the novice and experienced nurse. ConclusionThe NGT process identified human and system factors contributing to errors and impacting safe medication administration practices. Findings will support the creation of medication administration scenarios for use with immersive virtual reality simulation.

Establishing Radiological Screening Levels for Defense-related Uranium Mine (DRUM) Sites on BLM Land Using a Recreational Future-use Scenario.

Thousands of former uranium mining sites in the United States, primarily in the southwestern states of Colorado, Arizona, New Mexico, Arizona, and Utah, are being identified and evaluated to assess their potential for causing public and environmental impacts. The common radiological contaminant of concern that characterizes these sites is naturally occurring uranium ore and associated wastes that may have been left behind postmining. The majority of these sites were abandoned and in general, are referred to as abandoned uranium mines, regardless of the government authority currently managing the land or in some cases, assigned responsibility for the oversight of assessment and remediation. The U.S. Department of Energy has identified over 4,000 defense-related uranium mine sites from which uranium ore was purchased by the U.S. government for nuclear defense programs prior to 1970. U.S. Department of Energy has established a program to inventory and perform environmental screening on defense-related uranium mine sites. The focus of this paper is the approximately 2,400 defense-related uranium mine sites located on federal land managed by the Bureau of Land Management and the U.S. Forest Service. This paper presents the results of an analysis to develop radiological screening criteria for U.S. Department of Energy's defense-related uranium mine sites that can be used as input to the overall ranking of these sites for prioritization of additional assessment, reclamation, or remedial actions. For these sites managed by Bureau of Land Management, public access is typically limited to short-term use, primarily for recreational purposes. This is a broad category that can cover a range of possible activities, including camping, hiking, hunting, biking, all-terrain vehicle use, and horseback riding. The radiological screening levels were developed by calculating the radiological dose to future recreational users of defense-related uranium mine sites assuming a future camper spends two weeks per year at the site engaged in recreational activities. Although a number of possible exposure pathways were included in this analysis (inhalation and ingestion of dust and soil, radon and progeny inhalation, and gamma radiation exposure from the soil), it is desirable as a practical matter to determine what gamma exposure rate would ensure that the annual acceptable exposure as determined by the regulatory authority will not be exceeded in the future. Because these sites are generally remote and located in semiarid environments, traditional exposure scenarios often applied in these types of analyses (e.g., subsistent farmers and ranchers), including exposure pathways for the ingestion of locally grown food products and water, were not considered relevant to short-term recreational use.

Surface water risk assessment of pesticides in Ethiopia

Scenarios for future use in the pesticide registration procedure in Ethiopia were designed for 3 separate Ethiopian locations, which are aimed to be protective for the whole of Ethiopia. The scenarios estimate concentrations in surface water resulting from agricultural use of pesticides for a small stream and for two types of small ponds.Seven selected pesticides were selected since they were estimated to bear the highest risk to humans on the basis of volume of use, application rate and acute and chronic human toxicity, assuming exposure as a result of the consumption of surface water. Potential ecotoxicological risks were not considered as a selection criterion at this stage. Estimates of exposure concentrations in surface water were established using modelling software also applied in the EU registration procedure (PRZM and TOXSWA). Input variables included physico-chemical properties, and data such as crop calendars, irrigation schedules, meteorological information and detailed application data which were specifically tailored to the Ethiopian situation.The results indicate that for all the pesticides investigated the acute human risk resulting from the consumption of surface water is low to negligible, whereas agricultural use of chlorothalonil, deltamethrin, endosulfan and malathion in some crops may result in medium to high risk to aquatic species.The predicted environmental concentration estimates are based on procedures similar to procedures used at the EU level and in the USA. Addition of aquatic macrophytes as an ecotoxicological endpoint may constitute a welcome future addition to the risk assessment procedure. Implementation of the methods used for risk characterization constitutes a good step forward in the pesticide registration procedure in Ethiopia.

Use of SOFEA to Predict 1,3‐D Concentrations in Air in High‐Use Regions of California

Methyl bromide, a commonly used soil fumigant, is being phased out per the Montreal Protocol and multiple fumigants are being positioned as replacements. Most effective soil fumigants, including methyl bromide, have the potential for inhalation exposure if the material volatilizes from soil. Chronic exposures for the fumigant 1,3-dichloropropene (1,3-D) are managed in part by the California Department of Pesticide Regulation by limiting the annual amount that can be used within a given township. A stochastic/deterministic numerical system (SOil Fumigant Exposure Assessment system [SOFEA]) was developed using the USEPA air dispersion model ISCST3, field study observations for flux loss, and links to Geographic Information Systems (GIS). SOFEA was used retrospectively to simulate concentrations of 1,3-D in air for direct comparison with monitoring program observations conducted by California Air Resources Board in Fresno County. These results indicated slight overprediction but correct magnitudes for regional air concentrations, especially at the higher percentiles, and provide a performance test. SOFEA was also used, prospectively, to predict air concentrations in potential future-use scenarios. These simulations of chronic air concentrations in two high-use 1,3-D counties of California (Ventura, Merced) consisted of 25 contiguous townships treated either at 1.5 times the current township allocation (40,937 kg) or at the maximum levels of 1,3-D used between 1999 and 2006. Exposure predictions for large regions are necessary to evaluate chronic population-based lifetime exposure and risk to 1,3-D should use patterns change. SOFEA provides a tool to estimate regional air concentrations within high-use areas required for such risk assessments.

Prospects of solar thermal hydrogen production processes

This article provides a critical discussion of prospects of solar thermal hydrogen production in terms of technological and economic potentials and their possible role for a future hydrogen supply. The study focuses on solar driven steam methane reforming, thermochemical cycles, high temperature water electrolysis and solar methane cracking. Development status and technological challenges of the processes and objectives of ongoing research are described. Estimated hydrogen production costs are shown in comparison to other options. A summary of current discussions and today's scenarios of future use of hydrogen as an energy carrier and a brief overview on the development status of end-use technologies characterise uncertainties whether hydrogen could emerge as important energy carrier until 2050. Another focus is on industrial hydrogen demand in areas with high direct solar radiation which may be the main driver for the further development of solar thermal hydrogen production processes in the coming decades.

GWMR Focus Issue on Vapor Intrusion

The timing of this GWMR special focus issue roughly coincides with the 20th anniversary of the emergence of soil vapor intrusion to indoor air as an exposure pathway of concern for human health risks at sites with contaminated soil and ground water. In 1988, the Indoor Radon Abatement Act was promulgated and chlorinated solvent vapor intrusion was identified in the Hillside School in Needham, Massachusetts. At about the same time, the Johnson and Ettinger screening-level model was being developed to assess vapor intrusion risks at the Rocky Mountain Arsenal. In general, however, this pathway was seldom assessed until vapor intrusion cases in Colorado in the late 1990s gained attention in the press and raised the issue to national prominence. There are now about two dozen state-level guidance documents, a few federal guidance documents, and multiple documents from private companies or nongovernment organizations. Internationally, there is interest in vapor intrusion in several other countries (Canada, UK, EU, and Australia, to name a few). There are significant differences between jurisdictions in approaches, methods, policies, and screening levels (by up to several orders of magnitude). This indicates the limits of our collective understanding of the topic because the laws of physics, building ventilation practices, and human toxicology do not vary much between states or countries. The development of a simple recipe for assessing vapor intrusion has been elusive; regulatory agencies generally would like an assessment approach that minimizes false negatives (falsely concluding that vapor intrusion poses no significant risk), whereas responsible parties generally would like an approach that is practicable and minimizes both false negatives and false positives (falsely concluding that vapor intrusion does pose an unacceptable risk). Assessments can be challenging because typical indoor air concentrations in residences not affected by vapor intrusion approach risk-based target concentrations for several common chemicals. Considering all the attention paid to the vapor intrusion pathway, there has been very little funding for relevant pure or applied research in the past decade. For example, the Indoor Radon Abatement Act of 1988 allocated about $15 million/year of research and technical assistance funding. Recently, federal funding has been extended to a few studies of VOC vapor intrusion through the Environmental Security Technology Certification program (ESTCP) and the Strategic Environmental Research and Development Program (SERDP), although in much smaller amounts. Industry-funded programs have been few and small and largely led by the American Petroleum Institute and its member companies. As a result, much of what has been learned in the past decade has been based on studies conducted on an ad hoc basis with limited resources. Also, much of what has been learned has been shared in conference proceedings, or other non-peer-reviewed literature. This was a stimulus for this focus issue, which started about a year ago with an invitation sent to a large number of individuals active in this field, but with few or no publications in archival journals. The articles in this issue intentionally span a range of topics, including regulatory and public perspectives as well as traditional archival peer-review papers on sampling methods, empirical data variability, mathematical modeling, background concentrations, biodegradation of petroleum compounds, and more. We are grateful to the dozens of authors and coauthors as well as the dozens of peer reviewers for devoting their time to share the information contained herein. Schedule and space constraints prevented some papers from being published in this issue, and they will appear in coming issues. It will be interesting to see how the assessment and management of this exposure pathway progress. We need to develop and demonstrate the use of new data collection methods leading to confident characterization of long-term average exposures, because it is difficult to practicably reduce the uncertainty inherent in current point-in-time and point-in-space sampling methods given the spatial and temporal variations seen at research sites. In addition, we need improved techniques to discriminate between subsurface and indoor sources of indoor air contaminants, and improved predictive capabilities to address future-use scenarios at sites without buildings currently present or buildings where access for monitoring is denied. There are also several policy-related issues to consider, like those leading to screening levels that vary by several orders of magnitude, data sufficiency for reliable assessment, and relations with owners and occupants of potentially affected properties. There are significant challenges to overcome before we can screen and assess VOC vapor intrusion confidently and cost-effectively at all sites; in the meanwhile, there is an amazing opportunity for creative solutions to the current challenges. The readership of GWMR will no doubt be significant contributors to these solutions. We hope you enjoy this issue and look forward to future articles on this challenging and important topic.

Scenarios for Future Use of E-Democracy Tools in Europe

Many ICT-based tools for supporting democratic participation that have been developed with public funds and applied in pilot projects have not yet achieved large-scale outreach. Optimists still believe this will happen; sceptics doubt. This paper starts from the assumption that technological development and diffusion are largely influenced by socioeconomic conditions. It develops a contingency model for e-democracy tools and applies the scenario method for differentiating the future context of these tools. It is based on the results of a research project that described possible futures of European e-government in general and e-democracy in particular on a 10-year time horizon by using the scenario method and inputs from European experts on e-government. Out of three different scenarios, possible and plausible futures of e-democracy are described in order to analyse robust technologies that are expected to be used in all three scenarios.

04/01252 Hydrogen as an energy carrier: scenarios for future use of hydrogen in the Danish energy system: Sørensen, B. et al. International Journal of Hydrogen Energy, 2004, 29, (1), 23–32

04/01252 Hydrogen as an energy carrier: scenarios for future use of hydrogen in the Danish energy system: Sørensen, B. et al. International Journal of Hydrogen Energy, 2004, 29, (1), 23–32

Hydrogen as an energy carrier: scenarios for future use of hydrogen in the Danish energy system

Scenarios for a transition to a hydrogen society are constructed for Denmark. The physical basis for the scenarios is the exploitation of renewable energy resources already in progress in Denmark. Hydrogen is proposed as a convenient energy carrier due to its versatility in use, transmission and as an energy storage medium. Two main scenarios are constructed, differing in the degree of decentralisation of energy production and management: one resembles the current system with centralised facilities and commercial management, the other being based upon a projected scale-independent cost structure of energy producing and handling equipment, that will allow extreme decentralisation of the physical energy conversion system, possibly accompanied by a similar decentralisation of ownership and control. The simulation studies show that both scenarios are technically feasible, and that the storage problems arising from the mismatch between demand and intermittent sources can be solved in both a centralised and a decentralised fashion.

Influence of Soil Half-Life on Risk Assessment of Carcinogens

Risk estimates for contaminants in soil are currently calculated assuming that concentrations remain unchanged over time. In reality, biological and physicochemical processes can substantially diminish contaminant concentrations in soil. For exposure periods typically evaluated in USEPA risk assessments, failure to consider the decline in contaminant levels from environmental transport and degradation can result in a significant overestimation of the average daily dose of toxicant. This overestimation may be up to 2- to 3-fold for compounds with long half-lives (15-20 years) in soil and as much as 40-fold for compounds with short half-lives (0.5 years). Overestimation of dosages affects estimation of cancer risks because of the assumption that the probability of cancer increases directly with the cumulative dose of carcinogen. Thus, assuming static contaminant concentrations in soil adds unacknowledged conservatism to cancer risk estimates and target concentration limits. Furthermore, as significant time may elapse before future-use scenarios could possibly occur, soil half-life can affect the estimation of noncarcinogenic health hazards as well. Therefore, an increase in target concentration limits for some compounds could be allowed and corresponding remediation costs reduced by considering how soil half-life changes the dosage calculation. Specific examples of the influence of soil degradation rates on estimates of cancer risk are presented and the degree of added conservatism imparted to risk assessments through assumption of static site contaminant levels is discussed. Considering the potential importance of this parameter for risk assessment and risk management decisions, soil degradation of contaminants under site-specific conditions should be performed whenever possible and incorporated into the risk assessment exercise. When the soil degradation rate cannot be measured or reliably predicted, an estimate of the degree of conservatism should be made to provide risk managers with an appreciation of the degree of uncertainty in the calculation of risk.