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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 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Integrity and security in an Ada runtime environment

A review is provided of the Formal Methods group discussions. It was stated that integrity is not a pure mathematical dual of security. The input data is part of the integrity domain. The group provided a roadmap for research. One item of the roadmap and the final position statement are closely related to the space shuttle and space station. The group's position is to use a safe subset of Ada. Examples of safe sets include the Army Secure Operating System and the Penelope Ada verification tool. It is recommended that a conservative attitude is required when writing Ada code for life and property critical systems.

Bown, Rodney L.↗
NASA NTRS2002

Cell prestress. I. Stiffness and prestress are closely associated in adherent contractile cells

The tensegrity hypothesis holds that the cytoskeleton is a structure whose shape is stabilized predominantly by the tensile stresses borne by filamentous structures. Accordingly, cell stiffness must increase in proportion with the level of the tensile stress, which is called the prestress. Here we have tested that prediction in adherent human airway smooth muscle (HASM) cells. Traction microscopy was used to measure the distribution of contractile stresses arising at the interface between each cell and its substrate; this distribution is called the traction field. Because the traction field must be balanced by tensile stresses within the cell body, the prestress could be computed. Cell stiffness (G) was measured by oscillatory magnetic twisting cytometry. As the contractile state of the cell was modulated with graded concentrations of relaxing or contracting agonists (isoproterenol or histamine, respectively), the mean prestress ((t)) ranged from 350 to 1,900 Pa. Over that range, cell stiffness increased linearly with the prestress: G (Pa) = 0.18(t) + 92. While this association does not necessarily preclude other interpretations, it is the hallmark of systems that secure shape stability mainly through the prestress. Regardless of mechanism, these data establish a strong association between stiffness of HASM cells and the level of tensile stress within the cytoskeleton.

NASA Discipline Cell Biology↗
NASA NTRS2005

Irregular Satellites of the Planets

This proposal is directed towards the observational exploration of the irregular satellite systems of the planets. Primarily we use large-format CCD cameras on the world's largest telescopes, on Mauna Kea, to discover new irregular satellites and then to monitor their positions in order to ascertain their orbital characteristics. Separate observations are taken to determine the physical properties of the irregular satellites. The big picture science objective is to determine how these satellites were captures, and to use the properties of the satellites and their orbits to place constraints on early solar system (including formation) processes. Work in the first year has focussed on a major investigation of the Saturn irregular satellite system. We secured observing time on the Subaru and Gemini 8-m diameter telescopes in December 2004, January, February and March 2005 for the conduct of a deep, wide-area survey. This has resulted in the detection and orbit determination for 12 new satellites to be announced in the next week or two. Additional satellites were lost, temporarily, due to unusually poor weather conditions on Mauna Kea. These objects will be recovered and their orbits published next year. A separate survey of the Uranus irregular satellites was published (Sheppard, Jewitt and Kleyna 2005). Away from the telescope, we have discovered the amazing result that the four giant planets possess similar numbers of irregular satellites. This flies in the face of the standard gas-drag model for satellite capture, since only two of the giant planets are gas giants and the others (Uranus and Neptune) formed by a different process and in the absence of much gas. The constancy of the satellite number (each giant holds approximately 100 irregular satellites measured down to the kilometer scale) is either a coincidence, with different capture mechanisms at different planets giving by chance the same total numbers of irregular satellites, or indicates that the satellites were captured by a completely different process. We favor the latter (Jewitt and Sheppard 2005).

Jewitt, David↗
NASA NTRS2011

Schottky Heterodyne Receivers With Full Waveguide Bandwidth

Compact THz receivers with broad bandwidth and low noise have been developed for the frequency range from 100 GHz to 1 THz. These receivers meet the requirements for high-resolution spectroscopic studies of planetary atmospheres (including the Earth s) from spacecraft, as well as airborne and balloon platforms. The ongoing research is significant not only for the development of Schottky mixers, but also for the creation of a receiver system, including the LO chain. The new receivers meet the goals of high sensitivity, compact size, low total power requirement, and operation across complete waveguide bands. The exceptional performance makes these receivers ideal for the broader range of scientific and commercial applications. These include the extension of sophisticated test and measurement equipment to 1 THz and the development of low-cost imaging systems for security applications and industrial process monitoring. As a particular example, a WR-1.9SHM (400-600 GHz) has been developed (see Figure 1), with state-of-the-art noise temperature ranging from 1,000-1,800 K (DSB) over the full waveguide band. Also, a Vector Network Analyzer extender has been developed (see Figure 2) for the WR1.5 waveguide band (500 750 GHz) with 100-dB dynamic range.

Hesler, Jeffrey↗
NASA NTRS2011

Deployment of an Advanced Electrocardiographic Analysis (A-ECG) to Detect Cardiovascular Risk in Career Firefighters

INTRODUCTION: Sudden cardiac death is the leading cause of line of duty death among firefighters, accounting for approximately 45% of fatalities annually. Firefighters perform strenuous muscular work while wearing heavy, encapsulating personal protective equipment in high ambient temperatures, under chaotic and emotionally stressful conditions. These factors can precipitate sudden cardiac events like myocardial infarction, serious dysrhythmias, or cerebrovascular accidents in firefighters with underlying cardiovascular disease. PURPOSE: The purpose of this study was to deploy and then evaluate the contribution of resting advanced ECG (A-ECG) in addition to other screening tools (family history, lipid profiles, and cardiopulmonary exercise tests, XT) in assessment of an individual fs cardiac risk profile. METHODS: Forty-four career firefighters were recruited to perform comprehensive baseline assessments including tests of aerobic performance, fasting lipids and glucose. Five-min resting 12-lead A-ECGs were obtained in a subset of firefighters (n=21) and transmitted over a secure networked system to a NASA physician collaborator. Using myocardial perfusion and other imaging as the gold standard, A-ECG scoring has been proven useful in accurately identifying a number of cardiac pathologies including coronary artery disease (CAD), left ventricular hypertrophy, hypertrophic cardiomyopathy, and non-ischemic and ischemic cardiomyopathy. RESULTS: Subjects f mean (SD) age was 43 (8) years, weight 91 (13) kg, and BMI 28 (3) kg/m2. Fifty-one percent of subjects had .3 cardiovascular risk factors. One subject had ST depression on XT ECG, at least one positive A-ECG score for CAD, and documented CAD based on cardiology referral. While all other subjects, including those with fewer risk factors, higher aerobic fitness, and normal exercise ECGs, were classified as healthy by A-ECG, there was no trend for association between risk factors and any of 20 A-ECG parameters in the grouped data.

Dolezal, B. A.↗
NASA NTRS2018

Important Changes to User Access at the NASA CDDIS

The Crustal Dynamics Data Information System (CDDIS) supports data archiving and distribution activities for the space geodesy and geodynamics community. The main objectives of the system are to make space geodesy and geodynamics related data and derived products available in a central archive, to maintain information about the archival of these data, to disseminate these data and information in a timely manner to a global scientific research community, and to provide user based tools for the exploration and use of the archive. Since its inception, the user community has utilized anonymous ftp for accessing and downloading files from the CDDIS archive. Although this protocol allows users to easily automate file downloads, many organizations, data systems, and users have already migrated from ftp or are actively pursuing a move away from the protocol due to problems from a system and security standpoint. Furthermore, U.S. Government agencies have become increasingly concerned about this legacy protocol and ensuring data integrity for the user community have begun recently to disallow the use of the ftp protocol. The CDDIS, operated by NASA GSFC, must therefore address these concerns and provide alternative methods for access to its archive for continued easy and automated download of its contents. This poster will discuss the upcoming changes at CDDIS and provide examples on transitioning from anonymous ftp.

Noll, Carey E.↗
DOE OSTI2018

Intrinsic use control for system and use controlled component security

An Initialization Unit (IU) initiates an initial secure connection with an Intrinsic Use Control (IUC) Chip based on very large random numbers (VLRNs). The IUC Chip in turn initiates a secondary secure connection between it and one or more Use Controlled Components (UCCs). Polling by the IU allows confirmation of an ongoing secure connection, and also allows the IUC Chip to confirm the secondary secure connection to the UCCs. Removal or improper polling response from one of the UCCs results in a response from the IUC Chip that may include notification of tampering, or temporary or permanent discontinued operation of the offending UCC. Permanent discontinued operation may include destruction of the offending UCC, and cascaded discontinued operation of all other UCCs secured by the IUC Chip. A UCC may in turn be another nested layer of IUC Chips, controlling a corresponding layer of UCCs, ad infinitum.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

Intrinsic use control for system and use controlled component security

An Initialization Unit (IU) initiates an initial secure connection with an Intrinsic Use Control (IUC) Chip based on very large random numbers (VLRNs). The IUC Chip in turn initiates a secondary secure connection between it and one or more Use Controlled Components (UCCs). Polling by the IU allows confirmation of an ongoing secure connection, and also allows the IUC Chip to confirm the secondary secure connection to the UCCs. Removal or improper polling response from one of the UCCs results in a response from the IUC Chip that may include notification of tampering, or temporary or permanent discontinued operation of the offending UCC. Permanent discontinued operation may include destruction of the offending UCC, and cascaded discontinued operation of all other UCCs secured by the IUC Chip. A UCC may in turn be another nested layer of IUC Chips, controlling a corresponding layer of UCCs, ad infinitum.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2020

Intrinsic use control for system and use controlled component security

An Initialization Unit (IU) initiates an initial secure connection with an Intrinsic Use Control (IUC) Chip based on very large random numbers (VLRNs). The IUC Chip in turn initiates a secondary secure connection between it and one or more Use Controlled Components (UCCs). Polling by the IU allows confirmation of an ongoing secure connection, and also allows the IUC Chip to confirm the secondary secure connection to the UCCs. Removal or improper polling response from one of the UCCs results in a response from the IUC Chip that may include notification of tampering, or temporary or permanent discontinued operation of the offending UCC. Permanent discontinued operation may include destruction of the offending UCC, and cascaded discontinued operation of all other UCCs secured by the IUC Chip. A UCC may in turn be another nested layer of IUC Chips, controlling a corresponding layer of UCCs, ad infinitum.

Hart, Mark Miles↗
DOE OSTI2021

Communication system and method for applying security for a time sensitive network

A method includes identifying power connections between plural components of a time sensitive network (TSN) that are interconnected via a predetermined connection plan. The method also includes determining a topology of the components of the TSN based on the power connections. Also, the method includes scheduling flows for the TSN based on the topology determined based on the power connections.

Bush, Stephen Francis↗