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At least 1,099 records · Page 61
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Diabatic error and propagation of Majorana zero modes in interacting quantum dots systems

Motivated by recent experimental progress in realizing Majorana zero modes (MZMs) using quantum dot systems, we investigate the diabatic errors associated with the movement of those MZMs. The movement is achieved by tuning time-dependent gate potentials applied to individual quantum dots, effectively creating a moving potential wall. To probe the optimized movement of MZMs, we calculate the experimentally accessible time-dependent fidelity and local density-of-states using many-body time-dependent numerical methods. Furthermore, our analysis reveals that an optimal potential wall height is crucial to preserve the well-localized nature of the MZM during its movement. Moreover, we analyze diabatic errors in realistic quantum-dot systems, incorporating the effects of repulsive Coulomb interactions and disorder in both hopping and pairing terms. Additionally, we provide a comparative study of diabatic errors arising from the simultaneous versus sequential tuning of multiple gates during the MZMs movement. Finally, we estimate the timescale required for MZM transfer in a six-quantum-dot system, demonstrating that MZM movement is feasible and can be completed well within the qubit's operational lifetime in practical quantum-dot setups.

Density of states↗
DOE OSTI2025

Supporting Information for manuscript: “A latitudinal gradient in S/G lignin monomer ratio driven by laccase in natural poplar variants”

Lignin composition plays a crucial role in plant structural integrity and environmental adaptation. However, the genetic and molecular mechanisms underlying natural variation in lignin composition remain poorly understood. This study investigates the syringyl-to-guaiacyl (S/G) lignin monomer ratio across a natural population of Populus trichocarpa spanning a latitudinal gradient along the Northwest coast of North America. By integrating biochemical, genomic, and geographic analysis, we identify key gene variants associated with S/G ratio differences. These datasets provide valuable insights into the evolutionary and functional genomics of lignin composition and serve as a resource for developing poplar variants optimized for forestry and bioenergy applications.

Poplar, lignin composition, laccases, latitude, ad↗
DOE OSTI2021

How production networks amplify economic growth

Technological improvement is the most important cause of long-term economic growth. In standard growth models, technology is treated in the aggregate, but an economy can also be viewed as a network in which producers buy goods, convert them to new goods, and sell the production to households or other producers. We develop predictions for how this network amplifies the effects of technological improvements as they propagate along chains of production, showing that longer production chains for an industry bias it toward faster price reduction and that longer production chains for a country bias it toward faster growth. These predictions are in good agreement with data from the World Input Output Database and improve with the passage of time. The results show that production chains play a major role in shaping the long-term evolution of prices, output growth, and structural change.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2025

Be₂C as a neutron moderator for molten salt reactors: A first-principles study of structural, electronic, and defect properties

Beryllium carbide (Be 2 C), valued for its high neutron moderation efficiency and low absorption cross section, is a promising high-temperature neutron moderator for molten salt reactors. Its practical adoption, however, demands significant technological maturation, requiring comprehensive theoretical and experimental studies of its response to different conditions, including high temperature and irradiation. Here, we report initial results on the fundamental properties and radiation-induced defects of Be 2 C, focusing on antisites, vacancies, interstitial atoms, and Frenkel pairs in the Be and C sublattices. Using density functional theory (DFT) and ab initio molecular dynamics (AIMD), we calculate the defects formation and binding energies, evaluating their dependence on the supercell size, charge states, and chemical environment. In general, carbon defects exhibit higher formation energies, greater sensitivity to cell size, and stronger impacts on the density of states compared to beryllium defects, with charged state the effects being more pronounced. Static DFT reveals multiple metastable interstitial configurations, while AIMD identifies ground states as C-C <100> dumbbells and octahedral Be interstitials. In conclusion, the diversity of metastable configurations and defect states complicates the diffusion mechanisms, requiring further molecular dynamics analysis to elucidate the mechanisms and rates of radiation-induced atomic transport, as well as the structural stability of Be2C.

Ab initio modeling↗
NASA NTRS1992

[NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 18:] Scientific and Technical Information (STI) policy and the competitive position of the US aerospace industry

With its contribution to trade, its coupling with national security, and its symbolism of U.S. technological strength, the U.S. aerospace industry holds a unique position in the Nation's industrial structure. Federal science and technology policy and Federal scientific and technical information (STI) policy loom important as strategic contributions to the U.S. aerospace industry's leading competitive position. However, three fundamental policy problems exist. First, the United States lacks a coherent STI policy and a unified approach to the development of such a policy. Second, policymakers fail to understand the relationship of STI to science and technology policy. Third, STI is treated as a part of general information policy, without any recognition of its uniqueness. This paper provides an overview of the Federal information policy structure as it relates to STI and frames the policy issues that require resolution.

Hernon, Peter↗
NASA NTRS1992

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 18: Scientific and Technical Information (STI) policy and the competitive position of the US aerospace industry

With its contribution to trade, its coupling with national security, and its symbolism of U.S. technological strength, the U.S. aerospace industry holds a unique position in the Nation's industrial structure. Federal science and technology policy and Federal scientific and technical information (STI) policy loom important as strategic contributions to the U.S. aerospace industry's leading competitive position. However, three fundamental policy problems exist. First, the United States lacks a coherent STI policy and a unified approach to the development of such a policy. Second, policymakers fail to understand the relationship of STI to science and technology policy. Third, STI is treated as a part of general information policy, without any recognition of its uniqueness. This paper provides an overview of the Federal information policy structure as it relates to STI and frames the policy issues that require resolution.

Hernon, Peter↗
NASA NTRS1986

The Earth's magnetosphere as a sample of the plasma universe

Plasma processes in the Earth's neighborhood determine the environmental conditions under which space-based equipment for science or technology must operate. These processes are peculiar to a state of matter that is rare on Earth but dominates the universe as whole. The physical, and especially the electrodynamic, properties of this state of matter is still far from well understood. By fortunate circumstances, the magnetosphere-ionosphere system of the Earth provides a rich sample of widely different plasma populations, and, even more importantly, it is the site of a remarkable variety of plasma processes. In different combinations such processes must be important throughout the universe, which is overwhelmingly dominated by matter in the plasma state. Therefore, observations and experiments in the near-Earth plasma serve a multitude of purposes. They will not only (1) clarify the dynamics of the space environment but also (2) widen the understanding of matter, (3) form a basis for interpretating remote observations of astrophysical objects, thereby even (4) help to reconstruct events that led to the evolution of the solar system. Last but not least they will (5) provide know-how required for adapting space-based technology to the plasma environment. Such observations and experiments will require a close mutual interplay between science and technology.

Faelthammar, Carl-Gunne↗
NASA NTRS2005

The 2004 NASA Faculty Fellowship Program Research Reports

This is the administrative report for the 2004 NASA Faculty Fellowship Program (NFFP) held at the George C. Marshall Space Flight Center (MSFC) for the 40th consecutive year. The NFFP offers science and engineering faculty at U.S. colleges and universities hands-on exposure to NASA s research challenges through summer research residencies and extended research opportunities at participating NASA research Centers. During this program, fellows work closely with NASA colleagues on research challenges important to NASA's strategic enterprises that are of mutual interest to the fellow and the Center. The nominal starting and .nishing dates for the 10-week program were June 1 through August 6, 2004. The program was sponsored by NASA Headquarters, Washington, DC, and operated under contract by The University of Alabama, The University of Alabama in Huntsville, and Alabama A&M University. In addition, promotion and applications are managed by the American Society for Engineering Education (ASEE) and assessment is completed by Universities Space Research Association (USRA). The primary objectives of the NFFP are to: Increase the quality and quantity of research collaborations between NASA and the academic community that contribute to the Agency s space aeronautics and space science mission. Engage faculty from colleges, universities, and community colleges in current NASA research and development. Foster a greater public awareness of NASA science and technology, and therefore facilitate academic and workforce literacy in these areas. Strengthen faculty capabilities to enhance the STEM workforce, advance competition, and infuse mission-related research and technology content into classroom teaching. Increase participation of underrepresented and underserved faculty and institutions in NASA science and technology.

Pruitt, J. R.↗
DOE OSTI2020

Career Decisions and Los Alamos National Laboratory [Slides]

At Los Alamos, we deliver science and technology to protect our nation and promote world stability Los Alamos National Laboratory. Our mission began by applying science and technology to address an international crisis. Today, we are responsible for the design, engineering, and sustainment of the majority of the United States’ nuclear weapons capabilities. We also work to assess & reduce global nuclear danger. We offer unparalleled career opportunities in science, engineering, manufacturing, business, and more

99 GENERAL AND MISCELLANEOUS↗
NASA NTRS2001

X-traktor: A Rookie Robot, Simple, Yet Complex, Impeccably Designed, a Very Innovative Multidisciplinary Engineering Masterpiece

FIRST is the acronym of For Inspiration and Recognition of Science and Technology. FIRST is a 501.C.3 non-profit organization whose mission is to generate an interest in science and engineering among today's young adults and youth. This mission is accomplished through a robot competition held annually in the spring of each year. NASAs Marshall Space Flight Center, Education Programs Department, awarded a grant to Lee High School, the sole engineering magnet school in Huntsville, Alabama. MSFC awarded the grant in hopes of fulfilling its goal of giving back invaluable resources to its community and engineers, as well as educating tomorrow's work force in the high-tech area of science and technology. Marshall engineers, Lee High School students and teachers, and a host of other volunteers and parents officially initiated this robot design process and competitive strategic game plan. The FIRST Robotics Competition is a national engineering contest, which immerses high school students in the exciting world of science and engineering. Teaming with engineers from government agencies, businesses, and universities enables the students to learn about the engineering profession. The students and engineers have six weeks to work together to brainstorm, design, procure, construct, and test their robot. The team then competes in a spirited, 'no-holds barred' tournament, complete with referees, other FIRST-designed robots, cheerleaders, and time clocks. The partnerships developed between schools, government agencies, businesses, and universities provide an exchange of resources and talent that build cooperation and expose students to new and rewarding career options. The result is a fun, exciting, and stimulating environment in which all participants discover the important connections between classroom experiences and real-world applications. This paper will highlight the story, engineering development, and evolutionary design of Xtraktor, the rookie robot, a manufacturing marvel and engineering achievement.

Henderson, A. J., Jr.↗
NASA NTRS2002

Pittsburgh Public School District / Carnegie Mellon University Robotics Team Participation in the US First Competition

FIRST, For Inspiration and Recognition of Science and Technology, is an international program designed to encourage junior and senior high school students to participate in science and technology related activities. FIRST attempts to increase enthusiasm for technology by providing a competitive environment in which to demonstrate robotics technology designed for a particular set of tasks. Carnegie Mellon University provided student members of the project the opportunity to complete the design, construction, testing, and operation of a robot. Electrical, mechanical, and programming skills were stressed, with both adult and senior students acting as mentors for more junior members. Teamwork and integration was also stressed in order to provide students with a realistic feel for project-based work. Finally, an emphasis was placed on recruiting students with greater difficulty in entering technological fields: girls and ethnic minorities and students leaning toward humanities (especially art). Carnegie Mellon built a relationship with Taylor Allderdice High School that lasted four years. For four years, the success of the project increased each year. Each term, the students successfully designed and built a working robot that could fully participate in the competition. The enthusiasm of the students has been the cornerstone of the recruit of new students, keeping the project growing and vital. Carnegie Mellon's participation with Allderdice has been an overall great success.

Stroupe, Ashley↗
NASA NTRS2005

Organizing to Implement Technology in the NASA Science Organization

As part of a NASA reorganization to support the new Vision for Space Exploration, a number of space and Earth science activities were combined into a single organization. This merger provided an opportunity to review and revise technology development within the new entity. While this process has yet to be finalized, an overview . of some of the options and considerations is provided. Examples from one portion of the new entity, the Earth-Sun System Technology program, are used as illustrations.

Bauer, Robert↗
NASA NTRS1991

Evolution: bats, radar, and science (The Remote Sensing Award Lecture)

A parallel is drawn between the evolution of the bat and the evolution of the science and technology of radar and remote sensing to illustrate the importance of the role of Darwinian processes in the culture and practice of science and technology, and thus in the survival of their vitality. The lecture touches on several themes of interest to the science community, such as the relation between basic and applied science and engineering; research in academia, industry, and government laboratories; elite scientists; and the survival of a scientific institution.

Atlas, David↗
NASA NTRS1991

The National Space Grant College and Fellowship Program

This paper outlines the development of NASA's National Space Grant College and Fellowship Program. The program was introduced by Senator Bentsen (D-TX) and passed into law on October 30, 1987. NASA consulted with professional higher education associations in translating the law's provisions into program objectives. The objectives include the establishment of a national network of universities with interests and capabilities in aeronautics, space and related fields; the formation of cooperative programs among universities, aerospace industry, and federal, state and local governments; the broadening of interdisciplinary training, research and public-service programs related to aerospace; the recruiting and training of professionals, especially women and underrepresented minorities, for careers in aerospace science, and technology and allied fields; and, the development of a strong science, mathematics and technology base from elementary school through university levels.

Schwartz, Elaine T.↗
NASA NTRS2000

The University of Nebraska at Omaha Center for Space Data Use in Teaching and Learning

Within the context of innovative coursework and other educational activities, we are proposing the establishment of a University of Nebraska at Omaha (UNO) Center for the Use of Space Data in Teaching and Learning. This Center will provide an exciting and motivating process for educators at all levels to become involved in professional development and training which engages real life applications of mathematics, science, and technology. The Center will facilitate innovative courses (including online and distance education formats), systematic degree programs, classroom research initiatives, new instructional methods and tools, engaging curriculum materials, and various symposiums. It will involve the active participation of several Departments and Colleges on the UNO campus and be well integrated into the campus environment. It will have a direct impact on pre-service and in-service educators, the K12 (kindergarten through 12th grade) students that they teach, and other college students of various science, mathematics, and technology related disciplines, in which they share coursework. It is our belief that there are many exciting opportunities represented by space data and imagery, as a context for engaging mathematics, science, and technology education. The UNO Center for Space Data Use in Teaching and Learning being proposed in this document will encompass a comprehensive training and dissemination strategy that targets the improvement of K-12 education, through changes in the undergraduate and graduate preparation of teachers in science, mathematics and technology education.

Grandgenett, Neal↗
NASA NTRS1977

Advances in laser technology for the atmospheric sciences; Proceedings of the Seminar, San Diego, Calif., August 25, 26, 1977

These papers deal with recent research, developments, and applications in laser and electrooptics technology, particularly with regard to atmospheric effects in imaging and propagation, laser instrumentation and measurements, and particle measurement. Specific topics include advanced imaging techniques, image resolution through atmospheric turbulence over the ocean, an efficient method for calculating transmittance profiles, a comparison of a corner-cube reflector and a plane mirror in folded-path and direct transmission through atmospheric turbulence, line-spread instrumentation for propagation measurements, scaling laws for thermal fluctuations in the layer adjacent to ocean waves, particle sizing by laser photography, and an optical Fourier transform analysis of satellite cloud imagery. Other papers discuss a subnanosecond photomultiplier tube for laser application, holography of solid propellant combustion, diagnostics of turbulence by holography, a camera for in situ photography of cloud particles from a hail research aircraft, and field testing of a long-path laser transmissometer designed for atmospheric visibility measurements.

Trolinger, J. D.↗