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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 109 records · Page 6

Metallic Coating of Cerium Oxide Microspheres

The ability to remove heat is paramount to nuclear fuel performance and longevity. Retaining fission product and separating fuel from reactor coolant and the environment is also necessary to prevent radiological contamination. Conventional nuclear fuel for commercial light water reactors and radioisotope power systems (RPS) is composed of oxide powders pressed into a pellet (cm-scale) and then sealed into a metal cladding to confine the fuel. What typical fuels lack is a method to surround each particle of nuclear fuel in metal, thus providing a more intimate protection layer for accident tolerance and boosting the thermal extraction from the fuel element. In such a way, metal-coated fuel particles increase heat extraction efficiency over clad-pellet designs while increasing the accident tolerance of the fuel. Metal oxide microspheres have wide-ranging applications, including the realm of fuels for nuclear reactors and RPS. Microspheres of uranium oxide/uranium carbide, mixed uranium/plutonium oxides, transuranics, and thorium fuels have been extensively studied. Pacific Northwest National Laboratory has also demonstrated the production of 238 PuO 2 microspheres for RPS applications. Metal-coated oxide microsphere fuels may also be attractive for other applications such as nuclear thermal rockets, future nuclear reactor designs, and catalysts.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Crossroads of Nonproliferation and Safeguarding Technologies for Implementation in Molten Salt Reactors

Idaho National Laboratory (INL) recently conducted a workshop endorsed by the National Nuclear Security Administration (NNSA) under the auspices of the Defense Nuclear Nonproliferation R&D (DNN R&D) Office's Safeguards Portfolio. The workshop's primary objective was to foster an engaging dialogue among researchers, with a specialized emphasis on the safeguards pertaining to molten salt reactors. At INL, the installation of the state-of-the-art Molten Salt Thermophysical Examination Capability (MSTEC) is underway. This shielded argon glovebox facility, designed for both irradiated and non-irradiated actinide materials, represents the cutting edge of research infrastructure. MSTEC is poised to serve as a pivotal research platform in the realm of molten salt technology, with significant implications for safeguards applications. Participants of the workshop had the opportunity to tour the facilities, including the site where MSTEC is being installed, as well as to observe the INL's molten salt and pyroprocessing research hot cells. The event featured insightful presentations delving into molten salt chemistry and the MSTEC project. Each participating laboratory contributed to the discourse with presentations on their respective research efforts addressing safeguards in relation to molten salt reactors. The workshop culminated with a generative brainstorming session, where participants shared their thoughts on strategic integration with partner agencies, aiming to synergize efforts in advancing the field of nuclear safeguards.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Preferred Practices Through a Project Template

In the realm of scientific software development, adherence to best practices is often advocated. However, implementing these can be challenging due to differing opinions. Certain aspects, such as software licenses and naming conventions, are typically left to the discretion of the development team. Our team has established a set of preferred practices, informed by, but not limited to, widely accepted best practices. These preferred practices are derived from our understanding of the specific contexts and user needs we cater to. To facilitate the dissemination of these practices among our team and foster standardization with collaborating domain scientists, we have created a project template for Python projects. This template serves as a platform for discussing the implementation of various decisions. This paper will succinctly delineate the components that constitute an effective project template and elucidate the advantages of consolidating preferred practices in such a manner.

Zhang, Chen↗

Data Driven Approach to Public Opinion Mining on Autonomous Vehicles: Sentiment Analysis of Social Media Comments Using Large Language Models

In the realm of online identity, social media has emerged as a rich and dynamic source of user-generated content, making it an invaluable resource for understanding public sentiment on a wide range of topics. Individuals often share their raw emotions and candid opinions on these platforms without fear of judgment or backlash. In this study, we conduct a sentiment analysis on user comments collected from various online platforms, with a specific focus on discussions surrounding autonomous vehicles. Leveraging the capabilities of large language models (LLMs), we classify each comment into one of five sentiment categories: Very Negative, Negative, Neutral, Positive, and Very Positive. Our approach demonstrates the effectiveness of LLMs in capturing nuanced contextual sentiment, offering a scalable and state-of-the-art alternative to traditional manual annotation methods. The results reveal key trends and insights into public perception, enabling a deeper understanding of how autonomous vehicle technologies are received by the online community. Our findings underscore the dynamic nature of public sentiment, which is shaped not only by advances in autonomous vehicle technology but also by contextual events such as regulatory developments, political adjustment and safety incidents.

24 POWER TRANSMISSION AND DISTRIBUTION↗

LOW-ALTITUDE REPEATER SATELLITES

The new perspective that is forced upon us by the Space Age is oddly evident in the title of this paper. The key adjective is "low-altitude," evoking, perhaps, a picture of objects flying just above the rooftops. In the strange new realm of space, however, we are using a different order of measurement. The low-altitude satellites that I shall discuss will be moving in orbits anywhere from a few hundred to more than ten thousand miles above the Earth.

Low altitude↗

Conference on Nutrition in Space and Related Waste Problems

As part of a continuing process man constantly seeks new habitats. In the late 1950's, he ventured into a vast and challenging new habitat, extraterrestrial space. Extending the realm of human life has always been a challenge to man, and inherent to all successful extensions of man into new domains is his ability to provide the essentials for life itself, his nutrition and controlled use of metabolic products. The provision of these essential requirements has always been a challenge and a motivating force in maintaining and extending human life on Earth. This challenge has now been extended beyond the Earth. As illustrated in this volume, many men and women of vision who continually devote their energies to feeding man on Earth have accepted the additional challenge of nutrition in space. They have already made inroads into the new problem of nutrition and waste handling in space and have already collected much physiological, psychological, toxicological, and pathological data related to space nutrition, feeding and elimination. They have elucidated man-machine interactions and the effects of these interactions on alimentation and elimination requirements in space. Thus light has been shed on specific research and development programs needed to establish requirements for nutrition and handling of metabolic wastes during manned space missions of 20 days' to 3 years' duration. These initial accomplishments have entailed the considerable efforts of many people and the knowledge and experience in nutrition and feeding gained by the Space Science Board of the National Academy of Sciences. This volume clearly represents the ability of scientists, engineers, and administrators to attack a problem as it arises; it clearly demonstrates the capability of the scientific and engineering communities to combine efforts, mobilize quickly, and devote their talents to a national need

Space environment↗

Biology and the Exploration of Mars

Until recent years the origin of life and its possible occurrence elsewhere in the universe have been matters for speculation only. The rapid growth of molecular biology since 1940 has, to be sure, made it possible to discuss life's origins in far more precise and explicit terms than was possible earlier; and the subject entered a new experimental phase in the 1950's with successful abiogenic synthesis of important biochemical substances in conditions simulating the presumptive environment of the primitive Earth. But the real transformation that the subject has undergone stems from the spectacular growth of space technology in the last decade. The possibility of life's origin and occurrence on planets other than ours is no longer limited to idle speculation: it has entered the realm of the testable, of science in the strict sense. Given the rockets now available, and especially those available by 1969, it has become fully realistic to consider plans for the biological exploration of Mars. The study that this report seeks to interpret was initiated in June, 1964, by the Space Science Board of the National Academy of Sciences to examine this possibility. The working group comprised 36 people representing a broad spectrum of scientific interests: evolutionary biology, genetics, microbiology, biochemistry and molecular biology, animal physiology, soil chemistry, organic chemistry, planetary astronomy, geochemistry, and theoretical physics. The participants included some with considerable prior involvement in problems of space exploration and others with none. Advice was also sought outside the group of immediate participants on the potentialities of selected analytical methods for the experimental study of extraterrestrial life and its environment. More than 30 individuals contributed in this fashion written assessments of techniques in which they were particularly well versed. Our task was to examine the scientific foundations and merits of the proposal to undertake a biological exploration of Mars. What are the potential scientific yields? How valuable, if attained, would they be? What, in fact, is the possibility of life occurring on Mars? And of our detecting it with available and foreseeable technology? What could be achieved by further astronomical work from Earth? by Martian fly-by missions? by Martian orbiters? and Martian Landers? What payloads would we recommend for planetary missions? What timing and over-all strategy would we recommend for Martian exploration were we to consider it worthwhile at all? In brief, the over-all purpose was to recommend to. the government, through the Academy's Space Science Board, whether or not a biological exploration of Mars should be included in the nation's space program over the next few decades; and, further, to outline what that program, if any, should be.

CONFERENCE↗

Rolamite - A new mechanical design concept

Rolamite, a mechanical suspension system, provides substantial reductions in friction in the realm of extremely low bearing pressures. In addition, rolamite devices are easily microminiaturized, are extremely tolerant of production variations and are inherently capable of virtually all functions to construct most electromechanical devices.

Wilkes, D. F.↗

Rocket propulsion by thermonuclear micro-bombs ignited with intense relativistic electron beams.

Discussion of a method for the ignition of a thermonuclear microbomb by means of an intense relativistic electron beam with regard to its potential application to rocket propulsion. With such a system, exhaust velocities up to 1000 km/sec, corresponding to a specific impulse of 100,000 sec, seem to be within the realm of possibility. The rocket is propelled by a chain of thermonuclear microbombs exploded in a concave magnetic mirror produced by superconducting field coils. The magnetic pressure of the field reflects the fireball generated by the explosion. For the large capacitor bank required to generate the intense relativistic electron beam, a desirable lightweight design may be possible through use of ferroelectric materials. Because of the high cost of the T-D and He 3-D thermonuclear material, the system has to be optimized by minimizing the T-D and He 3-D consumption by a proper TD and He 3-D fuel to hydrogen propellant mass ratio, leading to a larger total system mass than would be absolutely necessary.

Winterberg, F.↗

Processor for high-density digital tape-recorded signals

Linear filter and detection theory can bear on problem of reconstructing recorded bit stream. Problem can be taken from realm of nonlinear problems even though basic record process is still recognized as highly nonlinear. Digital tape recorder can be modeled as particular type of linear communication channel with intersymbol interference.

Ashlock, J. C.↗

Application of sonic-boom minimization concepts in supersonic transport design

The applicability of sonic boom minimization concepts in the design of large supersonic transport airplanes capable of a 2500-nautical-mile range at a cruise Mach number of 2.7 is considered. Aerodynamics, weight and balance, and mission performance as well as sonic boom factors, have been taken into account. The results indicate that shock-strength nominal values of somewhat less than 48 newtons/sq m during cruise are within the realm of possibility. Because many of the design features are in direct contradiction to presently accepted design practices, further study of qualified airplane design teams is required to ascertain sonic boom shock strength levels actually attainable for practical supersonic transports.

Carlson, H. W.↗

Digital interactive image analysis by array processing

An attempt is made to draw a parallel between the existing geophysical data processing service industries and the emerging earth resources data support requirements. The relationship of seismic data analysis to ERTS data analysis is natural because in either case data is digitally recorded in the same format, resulting from remotely sensed energy which has been reflected, attenuated, shifted and degraded on its path from the source to the receiver. In the seismic case the energy is acoustic, ranging in frequencies from 10 to 75 cps, for which the lithosphere appears semi-transparent. In earth survey remote sensing through the atmosphere, visible and infrared frequency bands are being used. Yet the hardware and software required to process the magnetically recorded data from the two realms of inquiry are identical and similar, respectively. The resulting data products are similar.

Sabels, B. E.↗

Nonlinear response of plates subjected to inplane and lateral pressure pulses.

The nonlinear response of a rectangular plate exposed to a far-field sonic boom disturbance is studied. The plate is subjected to both lateral and in-plane disturbances. The lateral disturbance is in the form of an N-shaped pressure pulse, and the in-plane disturbance is represented by a sinusoidal pulse. The equations of motion are reduced to a set of nonlinear coupled ordinary differential equations using Galerkin's method. These equations are solved numerically using Hamming's (1959) modified predictor-corrector integration method. The effects of in-plane boundary conditions and in-plane inertia are investigated. The nonlinear results, when compared to the linear theory, serve to delineate the realm of validity of the linear theory.

Knapp, L. J.↗

Synthesis of oscillating adaptive feedback systems

A synthesis theory is developed which allows system design to proceed from practical specifications on system command and/or disturbance response to a design which is very nearly optimal in terms of feedback sensor noise effects. The approach taken is to replace the nonlinear element by a mean square error minimizing approximation (dual-input describing function), and then use linear frequency domain synthesis techniques subject to additional constraints imposed by the limit cycle and the approximator. Synthesis techniques are also developed for a similar system using an externally excited oscillating signal with the above approach. The results remove the design of the systems considered from the realm of simulation and experimentation, permitting true synthesis and the optimization that accompanies it.

Smay, J. W.↗

Evolution of the Moon's orbit and the origin of life

Indications about the past history of the lunar orbit that are yielded by palaeontological data derived from periodicities in fossil corals are shown to suggest that the moon approached the earth 2,850 plus or minus 250 Myr BP. Convergent evidence in the geological record indicates that a pulse of high temperature volcanism occurred about 2800 Myr BP. The implied catastrophe roughly coincides with the first records of life. It seems within the realm of possibility that a global thermal event might have been involved in the origin of life.

Turcotte, D. L.↗

Multiple rendezvous maneuvers at synchronous altitude

Rendezvous techniques between synchronous satellites were found using a cotangential elliptic phasing (CEP) transfer. This transfer is a closed elliptic orbit which is cotangent to the synchronous orbits of the chase vehicle and target satellite. The cotangent point lies on the line of apsides of the transfer orbit which coincides with the line of intersection of the synchronous orbits. The rendezvous maneuvers accomplish plane changes and phase shifts simultaneously, and these maneuvers are found to be optimal when the plane change is split equally between the velocity increments. The CEP transfer can be extended to several revolutions for a further reduction of fuel usage. A set of synchronous satellites was used in a simulated mission. An optimal sequence for rendezvous among these satellites was established such that the total sum of velocity increments is within the realm of estimated 1980 technology.

Creehan, E. J., Jr.↗

Symbol synchronizer assembly instability study, part 2

Data processing to develop a third-order phase model and to translate all such processed data to the frequency realm for further analysis was described. The frequency study yields a long frequency modulation (FM) drift sinusoid (1600-sec period), an impressed secondary drift wave with a period of about 116 sec, and a set of even harmonics of twice the ramp period-the latter arising from, and used to modify, the phase detector model. The result is applied secondarily to estimate the strong-signal SSA phase detector response "out-of-lock." Finally, the main drift components are verified against all available data, and the result is used to estimate minimum lock conditions and the SSA drift effect under normal operating modes. The instability problem appears marginally resolvable if the acquisition technique is modified.

Bunce, R. C.↗