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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Investigating the Vulnerabilities of the Direct Transfer Trip Scheme for Network Protector Units in the Secondary Networks of Electric Power Distribution Grids

Network protector units (NPUs) are crucial parts of the protection of secondary networks to effectively isolate faults occurring on the primary feeders. When a fault occurs on the primary feeder, there is a path of the fault current going through the service transformers that causes a negative flow of current on the NPU connected to the faulted feeder. Conventionally, NPUs rely on the direction of current with respect to the voltage to detect faults and make a correct trip decision. However, the conventional NPU logic does not allow the reverse power flow caused by distributed energy resources installed on secondary networks. The communication-assisted direct transfer trip logic for NPUs can be used to address this challenge. However, the communication-assisted scheme is exposed to some vulnerabilities arising from the disruption or corruption of the communicated data that can endanger the reliable operation of NPUs. This paper evaluates the impact of the malfunction of the communication system on the operation of communication-assisted NPU logic. To this end, the impact of packet modification and denial-of-service cyberattacks on the communication-assisted scheme are evaluated. The evaluation was performed using a hardware-in-the-loop (HIL) co-simulation testbed that includes both real-time power system and communication network digital simulators. This paper evaluates the impact of the cyberattacks for different fault scenarios and provides a list of recommendations to improve the reliability of communication-assisted NPU protection.

direct transfer trip↗
DOE OSTI2024

A Large Language Model for Determining Partial Tripping of Distributed Energy Resources

Knowing the status of individual distributed energy resources, i.e., being tripped or not, after a contingency can inform the development of an aggregated DER model. Here, this letter presents a large language model application to determine the partial tripping of distributed energy resources depending on the types, locations, and duration of faults in the transmission network. The large language model, or more specifically BERT-based approach can streamline the fault information into tokenized input, which not only reduces the complexity of the machine learning model but also demonstrates a robust performance with only limited data sets.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2024

EVI-RoadTrip™: Electric Vehicle Infrastructure for Road Trips [SWR-22-17]

The EVI-RoadTrip™ tool offers high-resolution refueling network design and analysis to inform electric vehicle (EV) charging infrastructure development for road trips or long-distance travels. EVI-RoadTrip helps infrastructure planners, analysts, and decision makers evaluate EV energy consumption and corresponding charging demands along the routes-between origin and destination. It considers the projected location and characteristics of charging stations, potential electric grid impacts, and required infrastructure improvements. Strategically located charging stations for long-distance travel are critical to enabling the widespread adoption of EVs by allowing them to travel further beyond city or town boundaries. Sophisticated analysis and planning can identify the points (e.g., corridors) that may require increased availability of EV charging stations to support electrified road trips.

Wood, Eric↗
DOE OSTI2026

Trip Report for Foreign Travel to France to attend IMORN-33, July 2026

This trip report summarizes the activities of a NCSP sponsored trip to the 33rd International Meeting on Reactor Noise (IMORN-33) held at the Laboratory of Subatomic Physics & Cosmology (LPSC) in Grenoble, France the week of July 6th, 2026.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1981

Acquisition of background and technical information and class trip planning

Instructors who are very familiar with a study area, as well as those who are not, find the field trip information acquisition and planning process speeded and made more effective by organizing it in stages. The stage follow a deductive progression: from the associated context region, to the study area, to the specific sample window sites, and from generalized background information on the study region to specific technical data on the environmental and human use systems to be interpreted at each site. On the class trip and in the follow up laboratory, the learning/interpretive process are at first deductive in applying previously learned information and skills to analysis of the study site, then inductive in reading and interpreting the landscape, imagery, and maps of the site, correlating them with information of other samples sites and building valid generalizations about the larger study area, its context region, and other (similar and/or contrasting) regions.

Mackinnon, R. M.↗
NASA NTRS1981

Notes for Brazil sampling frame evaluation trip

Field notes describing a trip conducted in Brazil are presented. This trip was conducted for the purpose of evaluating a sample frame developed using LANDSAT full frame images by the USDA Economic and Statistics Service for the eventual purpose of cropland production estimation with LANDSAT by the Foreign Commodity Production Forecasting Project of the AgRISTARS program. Six areas were analyzed on the basis of land use, crop land in corn and soybean, field size and soil type. The analysis indicated generally successful use of LANDSAT images for purposes of remote large area land use stratification.

Horvath, R.↗
NASA NTRS1990

Development of a two-stream mixing layer from tripped and untripped boundary layers

The effects of the state of the initial boundary layers on the development of a two-stream, plane mixing layer, with a velocity ratio of 0.6 are experimentally investigated. Spanwise-average profiles are compared for the first time. The results indicate that both the near and far-field growth rates for the untripped case are significantly higher than the tripped case. The maximum Reynolds stresses and higher-order products for the two cases behave very differently in the near-field, but asymptote to approximately the same constant levels far downstream. The mean velocity and turbulence profiles in this region also collapse adequately for the two cases when plotted in similarity coordinates. The distance required to achieve self-similarity is distinctly shorter for the tripped case, in contrast to previous observations. The higher growth rate for the untripped case is attributed to the presence of streamwise vortices which result in additional entrainment by the mixing layer.

Bell, James H.↗
NASA NTRS1992

Minimum impulse trajectories for Mars round trip missions

Data are presented for minimum-impulse earth-Mars round-trip trajectories for the 2010 to 2027 Mars launch opportunities. Round-trip mission times from 120 to 600 days, including a 30-day rendezvous at Mars, for direct trajectories and trajectories utilizing a Venus gravitational assist are considered. Optimal planetary launch and arrival dates and total impulse requirements are based on all maneuvers being performed propulsively with no finite burn or other losses. Direct trajectories have the lowest impulse requirements for shorter mission times and Venus gravitational assist trajectories have the lowest impulse requirements for longer mission times. It is shown that one can depart on trajectories to Mars, beginning with lower energy trajectories to the moon. The fuel savings varies, depending on the final energy level required and on the swingby procedure used. Procedures discussed include single lunar swingbys, double-powered or unpowered lunar swingbys, third lunar flybys a year later, and gravity assists by Venus and earth after the final lunar swingby.

Horvat, Glen M.↗
NASA NTRS1993

Fast Overcurrent Tripping Circuit

Fast overcurrent tripping circuit designed for incorporation into power metal oxide/semiconductor field-effect transistor (MOSFET) switching circuit. Serves as fast electronic circuit breaker by sensing voltage across MOSFET's during conduction and switching MOSFET's off within 1 microsecond after voltage exceeds reference value corresponding to tripping current. Acts more quickly than Hall-effect current sensor and, in comparison with shunt current-measuring circuits, smaller and consumes less power. Also ignores initial transient overcurrents during first 5 microseconds of switching cycle.

Sullender, Craig C.↗
NASA NTRS1993

Heat transfer in rotating serpentine passages with selected model orientation for smooth or skewed trip walls

Experiments were conducted to determine the effects of model orientation as well as buoyancy and Coriolis forces on heat transfer in turbine blade internal coolant passages. Turbine blades have internal coolant passage surfaces at the leading and trailing edges of the airfoil with surfaces at angles which are as large as +/- 50 to 60 degrees to the axis of rotation. Most of the previously-presented, multiple-passage, rotating heat transfer experiments have focused on radial passages aligned with the axis of rotation. Results from serpentine passages with orientations 0 and 45 degrees to the axis of rotation which simulate the coolant passages for the mid chord and trailing edge regions of the rotating airfoil are compared. The experiments were conducted with rotation in both directions to simulate serpentine coolant passages with the rearward flow of coolant or with the forward flow of coolant. The experiments were conducted for passages with smooth surfaces and with 45 degree trips adjacent to airfoil surfaces for the radial portion of the serpentine passages. At a typical flow condition, the heat transfer on the leading surfaces for flow outward in the first passage with smooth walls was twice as much for the model at 45 degrees compared to the model at 0 degrees. However, the differences for the other passages and with trips were less. In addition, the effects of buoyancy and Coriolis forces on heat transfer in the rotating passage were decreased with the model at 45 degrees, compared to the results at 0 degrees. The heat transfer in the turn regions and immediately downstream of the turns in the second passage with flow inward and in the third passage with flow outward was also a function of model orientation with differences as large as 40 to 50 percent occurring between the model orientations with forward flow and rearward flow of coolant.

Johnson, B. V.↗
NASA NTRS1995

Mars Pathfinder Landing Site Workshop 2: Characteristics of the Ares Vallis Region and Field Trips in the Channeled Scabland, Washington

This volume, the first of two comprising the technical report for this workshop, contains papers that have been accepted for presentation at the Mars Pathfinder Landing Site Workshop 2: Characteristics of the Ares Vallis Region, September 24-30, 1995, in Spokane, Washington. The Mars Pathfinder Project received a new start in October 1993 as one of the next missions in NASA's long-term Mars exploration program. The mission involves landing a single vehicle on the surface of Mars in 1997. The project is one of the first Discovery-class missions and is required to be a quick, low-cost mission and achieve a set of significant but focused engineering, science, and technology objectives. The primary objective is to demonstrate a low-cost cruise, entry, descent, and landing system required to place a payload on the martian surface in a safe, operational configuration. Additional objectives include the deployment and operation of various science instruments and a microrover. Pathfinder paves the way for a cost-effective implementation of future Mars lander missions. Also included in this volume is the field trip guide to the Channeled Scabland and Missoula Lake Break-out. On July 4, 1997, Mars Pathfinder is scheduled to land near 19.5 deg N, 32.8 deg W, in a portion of Ares Vallis. The landing ellipse covers a huge (100 x 200 km) area that appears to include both depositional and erosional landforms created by one or more giant, catastrophic floods. One of the best known terrestrial analogs to martian outflow channels (such as Ares Vallis) is the region known as the Channeled Scabland. The field trip guide describes some of the geomorphological features of the Channeled Scabland and adjacent Lake Missoula break-out area near Lake Pend Oreille, Idaho.

Golombek, M. P.↗
NASA NTRS2006

A Quick Method for Estimating Vehicle Characteristics Appropriate for Continuous Thrust Round Trip Missions Within the Solar System

A simple method of estimating vehicle parameters appropriate for interplanetary travel can provide a useful tool for evaluating the suitability of particular propulsion systems to various space missions. Although detailed mission analyses for interplanetary travel can be quite complex, it is possible to derive hirly simple correlations which will provide reasonable trip time estimates to the planets. In the present work, it is assumed that a constant thrust propulsion system propels a spacecraft on a round trip mission having equidistant outbound and inbound legs in which the spacecraft accelerates during the first portion of each leg of the journey and decelerates during the last portion of each leg of the journey. Comparisons are made with numerical calculations from low thrust trajectory codes to estimate the range of applicability of the simplified correlations.

Emrich, Bill↗
NASA NTRS2009

Aerothermodynamic Characteristics of Boundary Layer Transition and Trip Effectiveness of the HIFiRE Flight 5 Vehicle

An experimental wind tunnel test was conducted in the NASA Langley Research Center s 20-Inch Mach 6 Tunnel in support of the Hypersonic International Flight Research Experimentation Program. The information in this report is focused on the Flight 5 configuration, one in a series of flight experiments. This report documents experimental measurements made over a range of Reynolds numbers and angles of attack on several scaled ceramic heat transfer models of the Flight 5 vehicle. The heat transfer rate was measured using global phosphor thermography and the resulting images and heat transfer rate distributions were used to infer the state of the boundary layer on the windside, leeside and side surfaces. Boundary layer trips were used to force the boundary layer turbulent, and a study was conducted to determine the effectiveness of the trips with various heights. The experimental data highlighted in this test report were used determine the allowable roughness height for both the windside and side surfaces of the vehicle as well as provide for future tunnel-to-tunnel comparisons.

Berger, Karen T.↗
NASA NTRS2013

Aeroheating Measurement of Apollo Shaped Capsule with Boundary Layer Trip in the Free-piston Shock Tunnel HIEST

An aeroheating measurement test campaign of an Apollo capsule model with laminar and turbulent boundary layer was performed in the free-piston shock tunnel HIEST at JAXA Kakuda Space Center. A 250mm-diameter 6.4%-scaled Apollo CM capsule model made of SUS-304 stainless steel was applied in this study. To measure heat flux distribution, the model was equipped with 88 miniature co-axial Chromel-Constantan thermocouples on the heat shield surface of the model. In order to promote boundary layer transition, a boundary layer trip insert with 13 "pizza-box" isolated roughness elements, which have 1.27mm square, were placed at 17mm below of the model geometric center. Three boundary layer trip inserts with roughness height of k=0.3mm, 0.6mm and 0.8mm were used to identify the appropriate height to induce transition. Heat flux records with or without roughness elements were obtained for model angles of attack 28º under stagnation enthalpy between H(sub 0)=3.5MJ/kg to 21MJ/kg and stagnation pressure between P(sub 0)=14MPa to 60MPa. Under the condition above, Reynolds number based on the model diameter was varied from 0.2 to 1.3 million. With roughness elements, boundary layer became fully turbulent less than H(sub 0)=9MJ/kg condition. However, boundary layer was still laminar over H(sub 0)=13MJ/kg condition even with the highest roughness elements. An additional experiment was also performed to correct unexpected heat flux augmentation observed over H(sub 0)=9MJ/kg condition.

Hideyuki, TANNO↗
NASA NTRS2014

Round-Trip Solar Electric Propulsion Missions for Mars Sample Return

Mars Sample Return (MSR) missions could benefit from the high specific impulse of Solar Electric Propulsion (SEP) to achieve lower launch masses than with chemical propulsion. SEP presents formulation challenges due to the coupled nature of launch vehicle performance, propulsion system, power system, and mission timeline. This paper describes a SEP orbiter-sizing tool, which models spacecraft mass & timeline in conjunction with low thrust round-trip Earth-Mars trajectories, and presents selected concept designs. A variety of system designs are possible for SEP MSR orbiters, with large dry mass allocations, similar round-trip durations to chemical orbiters, and reduced design variability between opportunities.

Solar Electric Propulsion↗