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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

The critical role of soil moisture in compound hazards

Soil moisture regulates the exchange of energy, water, and carbon across land–vegetation–atmosphere interfaces. Extremes in soil moisture can amplify natural hazards through interactions with diverse Earth system processes. Despite its mechanistic importance, soil moisture remains underrepresented in hazard research and predictive frameworks. Here, in this study, we review our current understanding of the role of soil moisture in the evolution and onset of diverse compound hazards by synthesizing the latest findings from observational and modelling studies. We highlight key soil moisture mechanisms, including atmospheric feedbacks that amplify drought–heatwave–wildfire events, precipitation couplings that promote clustered storms, and threshold responses that drive vegetation die-offs, trigger landslides, and induce flooding. Persistent challenges in observational data, model representation and operational implementation have limited the integration of soil moisture into hazard early-warning systems. Addressing these gaps through advances in observations, data assimilation, and physics-based and data-driven modelling will enhance hazard prediction and preparedness in a rapidly changing world.

Li, Chuxuan [University of California, Los Angeles↗
DOE OSTI2018

Tower Illuminance Model (TIM): Interactive Real-Time Flyover Simulation Tool to Evaluate Glare and Avian-Flux Hazards

Solar glare reflections and avian solar-flux hazards are an important concern for concentrating solar installations. Reflected sunlight from 'standby' heliostats has been noted by pilots as potentially hazardous, and reports of birds being singed by concentrated sunlight has created concern. This paper presents the Tower Illuminance Model ('TIM'), a software application developed to investigate glare and avian-flux hazards at concentrating solar power towers in a convenient and interactive manner. TIM simulates a field of heliostats in standby mode, wherein sunlight is not reflected toward the central receiver but at some location in the airspace around the receiver. The user can select a range of aiming strategies and field configurations and can navigate the simulated airspace above the heliostat field in real-time using an interactive 3D interface. As the user 'flies' through the airspace, TIM calculates the irradiance, glare hazard, and potential avian flux hazard. TIM is currently undergoing validation and industry testing.

14 SOLAR ENERGY↗
DOE OSTI2024

Quantifying the compound hazard of freezing rain and wind gusts across CONUS

Abstract The co-occurrence of freezing rain, ice accumulation and wind gusts (FZG) poses a significant hazard to infrastructure and transportation. However, quantification of the frequency and intensity of FZG is challenged by the lack of direct icing measurements. In this work, we evaluate and then apply an energy balance model to high-frequency data collected during 2005–2022 to derive hourly ice accumulation at 883 stations across the contiguous USA. These estimates are combined with wind gust observations to compute time series of hourly FZG hazard magnitude using the Sperry–Piltz Ice Accumulation (SPIA) index. Results are evaluated using Storm Reports of damage and economic disruption. The hourly SPIA estimates are also used to (i) derive a geospatial atlas of the hazard including the 50 yr return period event intensities for each US state derived using superstations, and (ii) describe storylines of significant events in terms of meteorological drivers and socioeconomic impacts. The highest values of SPIA during the 18 yr study period occur in a region extending from the Southern Great Plains over the Midwest into the densely populated Northeast. States in these regions also have high 50 yr return period maximum radial ice accumulation of 3–5 cm and co-occurring wind gusts >30 ms −1 . These values are comparable to past estimates for the 500 yr event which may imply this hazard has been previously underestimated. This atlas can be used to inform optimal FZG hazard mitigation strategies for each state/region.

58 GEOSCIENCES↗
DOE OSTI2017

Evaluation of Heliostat Standby Aiming Strategies to Reduce Avian Flux Hazards and Impacts on Operational Performance

This paper presents a study of alternative heliostat standby aiming strategies and their impact on avian flux hazards and operational performance of a concentrating solar power plant. A mathematical model was developed that predicts the bird-feather temperature as a function of solar irradiance, thermal emittance, convection, and thermal properties of the feather. The irradiance distribution in the airspace above the Ivanpah Unit 2 heliostat field was simulated using a ray-trace model for two different times of the day, four days of the year, and nine different standby aiming strategies. The impact of the alternative aiming strategies on operational performance was assessed by comparing the heliostat slew times from standby position to the receiver for the different aiming strategies. Increased slew times increased a proxy start-up time that reduced the simulated annual energy production. Results showed that spreading the radial aim points around the receiver to a distance of ~150 m or greater reduced the hazardous exposure times that the feather temperature exceeded the hazard metric of 160 degrees C. The hazardous exposure times were reduced by ~23% and 90% at a radial spread of aim points extending to 150 m and 250 m, respectively, but the simulated annual energy production decreased as a result of increased slew times. Single point-focus aiming strategies were also evaluated, but these strategies increased the exposure hazard relative to other aiming strategies.

14 SOLAR ENERGY↗
DOE OSTI2012

Automated design synthesis of robotic/human workcells for improved manufacturing system design in hazardous environments [Slides]

Manufacturing tasks that are deemed too hazardous for workers require the use of automation, robotics, and/or other remote handling tools. The associated hazards may be radiological or non-radiological, and based on the characteristics of the environment and processing, a design may necessitate robotic labor, human labor, or both. There are also other factors such as cost, ergonomics, maintenance, and efficiency that also effect task allocation and other design choices. Handling the tradeoffs of these factors can be complex, and lack of experience can be an issue when trying to determine if and what feasible automation/robotics options exist. To address this problem, we utilize common engineering design approaches adapted more for manufacturing system design in hazardous environments. We limit our scope to the conceptual and embodiment design stages, specifically a computational algorithm for concept generation and early design evaluation. In regard to concept generation, we first develop the functional model or function structure for the process, using the common 'verb-noun' format for describing function. A common language or functional basis for manufacturing was developed and utilized to formalize function descriptions and guide rules for function decomposition. Potential components for embodiment are also grouped in terms of this functional language and are stored in a database. The properties of each component are given as quantitative and qualitative criteria. Operators are also rated for task-relevant criteria which are used to address task compatibility. Through the gathering of process requirements/constraints, construction of the component database, and development of the manufacturing basis and rule set, design knowledge is stored and available for computer use. Thus, once the higher level process functions are defined, the computer can automate the synthesis of new design concepts through alternating steps of embodiment and function structure updates/decomposition. In the process, criteria guide function allocation of components/operators and help ensure compatibility and feasibility. Through multiple function assignment options and varied function structures, multiple design concepts are created. All of the generated designs are then evaluated based on a number of relevant evaluation criteria: cost, dose, ergonomics, hazards, efficiency, etc. These criteria are computed using physical properties/parameters of each system based on the qualities an engineer would use to make evaluations. Nuclear processes such as oxide conversion and electrorefining are utilized to aid algorithm development and provide test cases for the completed program. Through our approach, we capture design knowledge related to manufacturing and other operations in hazardous environments to enable a computational program to automatically generate and evaluate system design concepts.

42 ENGINEERING↗
DOE OSTI2012

Composite Materials for Hazard Mitigation of Reactive Metal Hydrides.

In an attempt to mitigate the hazards associated with storing large quantities of reactive metal hydrides, polymer composite materials were synthesized and tested under simulated usage and accident conditions. The composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride. Composites with vinyl-containing siloxane oligomers were also polymerized with and without added styrene and divinyl benzene. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride reduced the inherent hydrogen storage capacity of the material. The composites were found to be initially effective at reducing the amount of heat released during oxidation. However, upon cycling the composites, the mitigating behavior was lost. While the polymer composites we investigated have mitigating potential and are physically robust, they undergo a chemical change upon cycling that makes them subsequently ineffective at mitigating heat release upon oxidation of the metal hydride. Acknowledgements The authors would like to thank the following people who participated in this project: Ned Stetson (U.S. Department of Energy) for sponsorship and support of the project. Ken Stewart (Sandia) for building the flow-through calorimeter and cycling test stations. Isidro Ruvalcaba, Jr. (Sandia) for qualitative experiments on the interaction of sodium alanate with water. Terry Johnson (Sandia) for sharing his expertise and knowledge of metal hydrides, and sodium alanate in particular. Marcina Moreno (Sandia) for programmatic assistance. John Khalil (United Technologies Research Corp) for insight into the hazards of reactive metal hydrides and real-world accident scenario experiments. Summary In an attempt to mitigate and/or manage hazards associated with storing bulk quantities of reactive metal hydrides, polymer composite materials (a mixture of a mitigating polymer and a metal hydride) were synthesized and tested under simulated usage and accident conditions. Mitigating the hazards associated with reactive metal hydrides during an accident while finding a way to keep the original capability of the active material intact during normal use has been the focus of this work. These composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride, in this case a prepared sodium alanate (chosen as a representative reactive metal hydride). It was found that the polymerization of styrene and divinyl benzene could be initiated using AIBN in toluene at 70°C. The resulting composite materials can be either hard or brittle solids depending on the cross-linking density. Thermal decomposition of these styrene-based composite materials is lower than neat polystyrene indicating that the chemical nature of the polymer is affected by the formation of the composite. The char-forming nature of cross-linked polystyrene is low and therefore, not an ideal polymer for hazard mitigation. To obtain composite materials containing a polymer with higher char-forming potential, siloxane-based monomers were investigated. Four vinyl-containing siloxane oligomers were polymerized with and without added styrene and divinyl benzene. Like the styrene materials, these composite materials exhibited thermal decomposition behavior significantly different than the neat polymers. Specifically, the thermal decomposition temperature was shifted approximately 100 °C lower than the neat polymer signifying a major chemical change to the polymer network. Thermal analysis of the cycled samples was performed on the siloxane-based composite materials. It was found that after 30 cycles the siloxane-containing polymer composite material has similar TGA/DSC-MS traces as the virgin composite material indicating that the polymer is physically intact upon cycling. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride in the form of a composite material reduced the inherent hydrogen storage capacity of the material. This reduction in capacity was observed to be independent of the amount of charge/discharge cycles except for the composites containing siloxane, which showed less of an impact on hydrogen storage capacity as it was cycled further. While the reason for this is not clear, it may be due to a chemically stabilizing effect of the siloxane on the metal hydride. Flow-through calorimetry was used to characterize the mitigating effectiveness of the different composites relative to the neat (no polymer) material. The composites were found to be initially effective at reducing the amount of heat released during oxidation, and the best performing material was the siloxane-containing composite which reduced the heat release to less than 50% of the value of the neat material. However, upon cycling the composites, all mitigating behavior was lost. The combined results of the flow-through calorimetry, hydrogen capacity, and thermogravimetric analysis tests lead to the proposed conclusion that while the polymer composites have mitigating potential and are physically robust under cycling, they undergo a chemical change upon cycling that makes them ineffective at mitigating heat release upon oxidation of the metal hydride.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Los Alamos National Laboratory Permit Modification Request for Technical Area 63 Transuranic Waste Facility Hazardous Waste Container Storage Unit (Rev. 3)

This Class 3 permit modification requests the addition of a hazardous waste management unit, the Transuranic Waste Facility (TWF), to the Los Alamos National Laboratory Hazardous Waste Facility Permit (November 2010), (hereinafter referred to as “the Permit”). The Permit was issued by the New Mexico Environment Department (NMED) in November, 1989 and renewed in 2010 (NMED 2010). The Los Alamos National Laboratory (LANL) Environmental Protection Agency (EPA) Identification Number is NM0890010515. The facility is owned by the National Nuclear Security Administration (NNSA) of the Department of Energy (DOE), and is operated jointly by NNSA-DOE and by Los Alamos National Security, LLC (LANS). This permit modification request has been prepared to address requirements in the New Mexico Administrative Code, Title 20, Chapter 4, Part 1 (20.4.1 NMAC), as revised October 2009, that are specific for the proposed new hazardous waste storage operations at the TWF. The renewed Permit contains many of the conditions addressing the requirements of the New Mexico Hazardous Waste Act (NMHWA) and implementing regulations, specifically 40 CFR, that are common to all LANL hazardous waste management units. The relevant sections of the Permit are referenced throughout this document. Together, information provided in this document and in the Permit will meet the applicable requirements specified in 40 CFR Parts 264 and 270 for the proposed unit.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Results of Testing the Relative Oxidizing Hazard of Wipes and KMI Zeolite

This report includes the results from testing performed on the relative oxidizing hazard of a number of organic sorbing wipe materials, as well as KMI zeolite. These studies were undertaken to address a need by the Los Alamos National Laboratory (LANL) Hazardous Materials Management group, which requires a material that can sorb small spills in a glovebox without creating a disposal hazard due to the potential for oxidation reactions, as requested in Request for Testing of Wipes and Zeolite for Los Alamos National Laboratory Hazardous Materials Group (NPl-7) (NPl-7-17-002) and Request for Testing of Chamois Material for Los Alamos National Laboratory Hazardous Materials Group (NPl-7) (NPl-7-17-005). This set oftests is a continuation of previous testing described in Results from Preparation and Testing of Sorbents Mixed with (DWT-RPT-003), which provided data for the Waste Isolation Pilot Plant's Basis of Knowledge. The Basis of Knowledge establishes criteria for evaluating transuranic (TRU) waste that contains oxidizing chemicals.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Studies for the requirements of automatic and remotely controlled shutoff valves on hazardous liquids and natural gas pipelines with respect to public and environmental safety

This study assesses the effectiveness of block valve closure swiftness in mitigating the consequences of natural gas and hazardous liquid pipeline releases on public and environmental safety. It also evaluates the technical, operational, and economic feasibility and potential cost benefits of installing automatic shutoff valves (ASVs) and remote control valves (RCVs) in newly constructed and fully replaced transmission lines. Risk analyses of hypothetical pipeline release scenarios are used as the basis for assessing: (1) fire damage to buildings and property in Class 1, Class 2, Class 3, and Class 4 high consequence areas (HCAs) caused by natural gas pipeline releases and subsequent ignition of the released natural gas; (2) fire damage to buildings and property in HCAs designated as high population areas and other populated areas caused by hazardous liquid pipeline releases and subsequent ignition of the released propane; and (3) socioeconomic and environmental damage in HCAs caused by hazardous liquid pipeline releases of crude oil. These risk analyses use engineering principles and fire science practices to characterize thermal radiation effects on buildings and humans and to quantify the total damage cost of socioeconomic and environmental impacts. The risk analysis approach used for natural gas pipelines is consistent with risk assessment standards developed by industry and incorporated into Federal pipeline safety regulations. Feasibility evaluations for the hypothetical pipeline release scenarios considered in this study show that installation of ASVs and RCVs in newly constructed and fully replaced natural gas and hazardous liquid pipelines is technically, operationally, and economically feasible with a positive cost benefit. However, these results may not apply to all newly constructed and fully replaced pipelines because site-specific parameters that influence risk analyses and feasibility evaluations often vary significantly from one pipeline segment to another and may not be consistent with those considered in this study. Consequently, the technical, operational, and economic feasibility and potential cost benefits of installing ASVs and RCVs in newly constructed or fully replaced pipelines need to be evaluated on a case-by-case basis. In theory, installing ASVs and RCVs in pipelines can be an effective strategy for mitigating potential consequences of unintended releases because decreasing the total volume of the release reduces overall impacts on the public and to the environment. However, block valve closure has no effect on preventing pipeline failure or stopping the product that remains inside the isolated pipeline segments from escaping into the environment. The benefits in terms of cost avoidance attributed to block valve closure swiftness increase as the time required to isolate the damaged transmission pipeline segment decreases. Block valve closure swiftness is most effective in mitigating damage resulting from a pipeline release and subsequent fire when the damaged pipeline segment is isolated and the thermal radiation produced by the fire declines in time so that emergency responders can safely begin fire fighting activities immediately upon arrival at the scene. Similarly, the avoided cost of socioeconomic and environmental damage for hazardous liquid pipeline releases without ignition increase as time required to isolate the damaged pipeline segment decreases.

03 NATURAL GAS↗
DOE OSTI2017

Final Hazard Classification Request for Not More Than 5 Percent Explosives in Solvent Mixtures

This report requests a non-explosive hazard classification of trace explosives in solution. UN Series 1 and 2 explosive hazard classification tests were performed on a simulated worst-case waste stream of five (5) percent by weight of explosive (CL-20) dissolved in a solvent solution (acetone) for transport and storage. The explosive hazard classification test results reported the sample to be non-explosive and the report provides the necessary data for the Department of Transportation to determine and assign the appropriate hazard class for five (5) percent or less of trace explosive in solvent solutions when being shipped and/or stored. Based on the test results, this report requests that the Department of Transportation assign a hazard class of 3, Desensitized explosive liquid, n.o.s. for this type of substance.

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

Probabilistic Seismic Hazard Assessment for Georgia

Probabilistic Seismic Hazard Assessments (PSHA) form the basis for most contemporary seismic provisions in building codes around the world. The current building code of Georgia (2009) is not fully compatible with seismic hazard and design concepts of modern codes. The Ministry of Economy and Sustainable Development of Georgia is currently undertaking an update to the building code to align it with EuroCode. In conjunction with EuroCode, a National Annex specific to Georgia is needed, including seismic hazard values for the territory of Georgia. A comprehensive earthquake catalogue is fundamental to a robust PSHA in the region. The Caucasus has had an uneven seismic recording and reporting history both temporally and spatially. Therefore, there has been a strong regional effort to bring together data from all the countries in the Caucasus, to digitize and standardize paper-based data from the Soviet era, and to re-examine magnitude and location calculations. The earthquake catalogue resulting from this effort forms the basis for a reliable seismic hazard assessment. Recognizing these needs, the U.S. Department of Energy through Lawrence Livermore National Laboratory (LLNL) initiated a project in 2015 to engage and train local scientists in the Caucasus to install new equipment, to enhance the quality of seismic monitoring and reporting, and to improve and harmonize the regional earthquake catalogue. In 2016, the project scope was expanded to include the modernization of seismic hazard assessments. To this end, a series of workshops were held in Georgia, the first one of which presented an overview of PSHA and its components to various participants from the universities and other research organizations in the region. This kick-off workshop was followed by numerous hands-on training workshops in 2017 and 2018, covering all aspects of PSHA. In addition to their training goals, the workshops brought together existing and new information relevant to PSHA studies in the region, providing a platform for local scientists/engineers and experts from other parts of the world to interact, cooperate and discuss various pieces of the PSHA input. This report outlines the aspects of the earthquake catalogue development and PSHA project that were specifically undertaken to form the basis for the building code update in Georgia. Georgia straddles the Greater Caucasus and Lesser Caucasus Fold and Thrust belts, where the convergent tectonic setting generates significant earthquake activity. To the east of the country, evidence indicates the possibility of a remnant subducting slab that causes earthquakes deeper than 40km. This study systematically compiles and improves all available data on local seismicity, active faults, and ground motion attenuation characteristics of the region; and builds a framework to enable a contemporary PSHA to be carried out with the engagement of local scientists. To this end, six regional workshops were organized in total over a three-year period of time, with participation from the United States, Canada and Hungary as well as countries in the Caucasus: Georgia, Armenia, Azerbaijan and Turkey. The workshops served multiple purposes such as training, data collection, interactions between local earth scientists and engineers, and brainstorming and knowledge exchange among local and international experts.

Geosciences↗
DOE OSTI2020

Evaluation of the lgnitability Hazards in Remediated Nitrate Salt Waste

The hazards associated with the characteristic of ignitability in remediated nitrate salt (RNS) waste containing nitric acid (HNO 3 ) and metal nitrate salts, currently stored at the Waste Control Specialists (WCS) facility near Andrews, Texas have been evaluated. For these waste drums there are two ignitability hazards that may apply, each separately distinguished from the other and uniquely correlated to one of two competing reaction mechanisms. One ignitability hazard, designated the autocatalytic thermal runway, is uniquely correlated to an acid/base reaction of hydrolysis of a hydrated metal nitrate salt. The other applicable ignitability hazard, designated the oxidizer property, is uniquely correlated to a redox disproportionation reaction involving an anhydrous metal nitrate salt. Which reaction mechanism pathway is accessible to a given metal nitrate, and therefore which ignitability hazard may apply, depends on the acidity of the metal ion and its corresponding capacity to maintain coordination with water.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Multi-Mechanism Flood Hazard Assessment: Example Use Case Studies

Multi-mechanism flood (MMF) events are caused by the combined effects of more than one flooding mechanism. Although floods can result from the occurrence of individual flood mechanisms, they can (and often do) result from multiple flooding mechanisms. MMF events may be more severe than single mechanism events, or they may differ in characteristics. To facilitate comprehensive risk-informed decision-making to protect against and mitigate the effects of flood events, understanding the hazard contributions from MMFs is important. Nevertheless, conventional probabilistic flood hazard assessment approaches typically focus on individual flood hazard mechanisms. This report is part of a research project funded by the US Nuclear Regulatory Commission (NRC) intended to assist NRC in developing the technical basis for guidance on developing probabilistic estimates of flood hazards for combinations of flood mechanisms. Specifically, the purpose of this report is to document two case studies to illustrate approaches for quantifying MMF hazards for inland and coastal flooding scenarios.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

The Value of Sharing and Consolidating Critical Community, Electricity, and Natural Hazard Information

The California Public Utilities Commission (CPUC) sought support for the development of database schema specifications for a bi-directional data portal that would foster cross-jurisdictional collaboration necessary to improve resilient energy infrastructure planning processes. This technical assistance activity involved Berkeley Lab researchers reviewing 34 local/tribal government hazard mitigation plans to assess (1) the natural hazards that communities are most concerned about; (2) the variety of–and terminology used to describe–critical community infrastructure; and (3) the availability of GIS information that could be incorporated into CPUC-mandated "Microgrid Planning Portals". In addition, we develop a common, but generic data taxonomy showing what fields to collect to encourage consolidating and sharing of this information in the future. Finally, we partnered with the Bishop Paiute tribal government to demonstrate the value of combining electricity infrastructure, natural hazard layers, and critical community infrastructure into a series of maps. The project demonstrated that a single system containing both electric utility and community infrastructure data—as well as information about natural hazards—will help the state of California, the IOUs, first responders, and long-term planners better prepare for—and thus lower their exposure to these ongoing and emerging hazards. The project also identified a number of challenges that will need to be overcome before it is possible to stand up a single system to display this information.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2023

A mechanistic model of a PWR-based nuclear power plant in response to external hazard-induced station blackout accidents

Natural hazard-induced nuclear accidents, such as the Fukushima Daiichi Accident that occurred in Japan in 2011, have significantly increased reactor safety studies in understanding nuclear power plant (NPP) responses to external hazard events such as earthquakes and floods. Natural hazards could cause the loss of offsite power in nuclear power plants, potentially leading to a Station Blackout (SBO) accident that significantly contributes to the overall risk of nuclear power plant accidents. Despite the fact that extensive research has been conducted on the station blackout accident for nuclear power plant, further understanding of these events is needed, particularly in the context of the dynamic nature of external hazards such as external flooding. This paper estimates the progression of station blackout events for a generic pressurized water reactor (PWR) in response to external flooding events. The original RELAP5-3D model of the Westinghouse four-loop design pressurized water reactor was adopted and modified to simulate the external flood-induced station blackout accident, including the short-term and long-term station blackout scenarios. A sensitivity analysis of long-term station blackout, examining reactor operation times and analyzing key parameters over time, was also conducted in this work. The results of the analyses, especially the critical timing parameters of key event sequences, provide useful insights about the time during the external flooding event, which is important for plant operators to make timely decisions to prevent potential core damage. This paper represents significant progress toward developing an integrated risk assessment framework for further identifying and assessing the effects of the critical sources of uncertainties of nuclear power plant under external hazard-induced events.

Liu, Tao↗
NASA NTRS1976

Wake vortex encounter hazards criteria for two aircraft classes

An investigation was conducted using a piloted, motion-base simulator to determine wake vortex hazard criteria for two classes of jet transport aircraft. A light business jet and a large multiengine jet transport were represented respectively. The hazard boundaries were determined in terms of the maximum bank angle due to the vortex encounter. Upsets as small as 7 deg in bank angle were considered to be hazardous at breakout altitude (200 ft (61.0 m)) for Instrument Flight Rule (IFR) and at 50 ft (15.2 m) for Visual Flight Rule (VFR) for both aircraft classes. Proximity to the ground was the primary reason for a hazardous rating. This was reflected in the reduction in the maximum bank angle at the hazard boundary and in more consistent ratings as altitude was decreased.

Sammonds, R. I.↗
NASA NTRS1981

Operational evaluation of thunderstorm penetration test flights during project Storm Hazards '80

The National Aeronautics and Space Administration is conducting a research project called Storm Hazards '80 in order to study the prediction, detectability and avoidance of the hazards of severe storms for aircraft operations. The project, using a highly instrumented NASA F-106B airplane to penetrate thunderstorms, gathered and correlated data from both airborne and ground based instrumentation. The objectives of this project are to determine the effects of lightning on the design and operation of aircraft composite structures and digital electronic systems. The data will be used to determine the correlation of lightning hazards with other severe storm hazards, such as heavy precipitation, hail, turbulence and wind-shear, in order to develop an initial data base for use in design and avoidance. The NASA F-106B was equipped with a weather radar, stormscope, lightning measurement instrumentation and air sampling equipment. This paper will focus on the operational aspects of thunderstorm penetrations and the pilot techniques used to avoid the extremely hazardous portions of the storm such as the tornadoes and hail. It will deal with the effects of the storm elements on the aircraft hardware, avionics and the crew.

Keyser, G. L., Jr.↗
NASA NTRS1986

A comparison of the explosion hazards of hydrazine and methylhydrazine in aerospace environments

A comparison of the explosion hazards of hydrazine and methylhydrazine fuels in aerospace environments is presented. Hazards are divided into three broad areas: hazards resulting from incompatibility of the fuels with materials they might contact, hazards resulting from ignition of the fuels, and unusual hazards resulting from the wide range of pressures to which these fuels are exposed in aerospace applications.

Benz, F. J.↗