Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “recent availability”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 829 records · Page 46

The NASA Biological Institutional Scientific Collection (NBISC): Tissue and Microbe Biospecimens to Advance Space Research

The NASA Biological Institutional Scientific Collection (NBISC) is a biorepository of non-human biospecimens from NASA-funded spaceflight investigations and correlative ground studies. The collection has its roots in the 1960s through collaborations by NASA Ames Research Center with other NASA centers, universities, and international space agencies by sharing non-human biospecimens from spaceflight and space-relevant ground experiments. These collaborations have advanced the field of space exploration by helping to maximize the data gained from spaceflight and other NASA-funded experiments. NBISC coordinates closely with the Biospecimen Sharing Program (BSP) which is responsible for organized sample collection from spaceflight and ground rodent experiments. In 2022 NBISC partnered with HRP’s Biospecimen and Tissue Sharing Collection (BTSC) Program to also archive samples from HRP’s Space Radiation Element-funded studies which primarily involve rodents exposed to various radiation protocols at the NASA Space Radiation Laboratory (NSRL) and other analog facilities. To date, more than fifty thousand biospecimens from BTSC have been transferred to NBISC for distribution to the community. In 2023, NBISC embarked on a new Space Biology funded endeavor to create the Space Microbial Culture Collection (SMCC) which will serve as a central repository for microbial isolates associated with space flight, gravitational, and space radiation research. This presentation will highlight several success stories of analyses carried out using archived NBISC samples received by researchers in recent years and will detail the process for proposing and receiving samples from NBISC, BTSC and SMCC. Making available these 150,000+ unique biospecimens to the scientific research community, NBISC not only serves as a repository for storing and distributing non-human biospecimens, but also acts as a resource to enable new discoveries that will benefit NASA and humankind.

Biospecimen↗

Jemez Pueblo Agriculture: Monitoring Rangeland Conditions to Inform Drought and Land Management in New Mexico

The Jemez Pueblo, a community located in the semi-arid high desert region of northcentral New Mexico, faces challenges with drought mitigation and livestock management. NASA DEVELOP partnered with the Pueblo of Jemez Natural Resources Department and The Nature Conservancy to provide recent and historical rangeland conditions to aid present decision-making, which relies on cultural practices, site familiarity, available resources, and physical data. This partnership offers the opportunity to support management practices by leveraging remote sensing and virtual fencing technologies. Our project explored Rangeland Analysis Platform (RAP) products incorporating NASA Earth observation Landsat 5 TM, Landsat 7 ETM+, Landsat 8 OLI, and Landsat 9 OLI-2 remote-sensed imagery as an agricultural land management tool. We performed linear regression analysis to evaluate RAP data to field data and explored RAP annual herbaceous biomass, ground cover trends, and climatic factors at the pasture level. We then computed study area summary statistics, performed pixel-by-pixel trend analysis across the study period, and evaluated ground cover trends near water sources. Based on available data, RAP was poorly correlated to bare ground and herbaceous biomass, generally underestimating the former and overestimating the latter. To improve the evaluation of RAP products, we suggest increasing the spatiotemporal distribution of the field dataset. According to RAP, from 1986 to 2023, the site became hotter and drier, bare ground increased, and annual forbs and grasses increased while perennials decreased. RAP products did not agree with field-collected data; however, the trends over time may be useful for informing rangeland management actions.

cattle grazing management↗

Imaging Radar in the Mojave Desert-Death Valley Region

The Mojave Desert-Death Valley region has had a long history as a test bed for remote sensing techniques. Along with visible-near infrared and thermal IR sensors, imaging radars have flown and orbited over the area since the 1970's, yielding new insights into the geologic applications of these technologies. More recently, radar interferometry has been used to derive digital topographic maps of the area, supplementing the USGS 7.5' digital quadrangles currently available for nearly the entire area. As for their shorter-wavelength brethren, imaging radars were tested early in their civilian history in the Mojave Desert-Death Valley region because it contains a variety of surface types in a small area without the confounding effects of vegetation. The earliest imaging radars to be flown over the region included military tests of short-wavelength (3 cm) X-band sensors. Later, the Jet Propulsion Laboratory began its development of imaging radars with an airborne sensor, followed by the Seasat orbital radar in 1978. These systems were L-band (25 cm). Following Seasat, JPL embarked upon a series of Space Shuttle Imaging Radars: SIRA (1981), SIR-B (1984), and SIR-C (1994). The most recent in the series was the most capable radar sensor flown in space and acquired large numbers of data swaths in a variety of test areas around the world. The Mojave Desert-Death Valley region was one of those test areas, and was covered very well with 3 wavelengths, multiple polarizations, and at multiple angles. At the same time, the JPL aircraft radar program continued improving and collecting data over the Mojave Desert Death Valley region. Now called AIRSAR, the system includes 3 bands (P-band, 67 cm; L-band, 25 cm; C-band, 5 cm). Each band can collect all possible polarizations in a mode called polarimetry. In addition, AIRSAR can be operated in the TOPSAR mode wherein 2 antennas collect data interferometrically, yielding a digital elevation model (DEM). Both L-band and C-band can be operated in this way, with horizontal resolution of about 5 m and vertical errors less than 2 m. The findings and developments of these earlier investigations are discussed.

Farr, Tom G.↗

Multibody dynamics model building using graphical interfaces

In recent years, the extremely laborious task of manually deriving equations of motion for the simulation of multibody spacecraft dynamics has largely been eliminated. Instead, the dynamicist now works with commonly available general purpose dynamics simulation programs which generate the equations of motion either explicitly or implicitly via computer codes. The user interface to these programs has predominantly been via input data files, each with its own required format and peculiarities, causing errors and frustrations during program setup. Recent progress in a more natural method of data input for dynamics programs: the graphical interface, is described.

Macala, Glenn A.↗

Combustion of Interacting Droplet Arrays in a Microgravity Environment

This research program involves the study of single droplets and linear arrays of droplets in weakly-buoyant and non-bouyant environments. The primary purpose of the single droplet work was to (1) provide a data base from which to compare droplet array results and (2) to correlate the effects of buoyancy on flame shape. Traditionally convective effects in droplet combustion are represented in terms of the Reynolds number, Re, for forced convection and the Grashof number, Gr, for natural convection. Typically, corrections to the burning rate constant for convective effects are written in terms of Re or Gr(exp 1). The Stefan velocity is not included in these correlations, even though from purely physical reasons, one would expect it to be important, especially at higher burning rates. The flame distortion due to convective effects is less documented quantitatively. Kumagai and Isoda do predict flame shape in natural and forced convective flow fields. Their focus, however, was to predict the actual flame dimensions. Law and co-workers used reduced pressure, high oxidizer ambients to obtain spherical flames. This implies that buoyant flows were reduced at the low pressures, as indicated by a very small Grashof number. Ross et al, however, using scaling arguments showed that reducing the pressure does not have a large effect on the magnitude of the buoyant velocity. Struk et al showed elongated flame shapes during simulated (porous sphere) droplet combustion. The elongation of the flames was due to residual gravity levels aboard the reduced gravity aircraft on which the experiments were conducted. These flame shapes, as well as some data from the literature were interpreted based on a dimensionless grouping called the sphericity parameter, Sp. Sp is the ratio of a characteristic computed buoyant velocity to the Stefan velocity at the flame front. One purpose of the droplet arrays work is to extend the database and theories that exist for single droplets into the regime where droplet interactions are important. The eventual goal being to use the results of this work as inputs to models on spray combustion where droplets seldom burn individually; instead the combustion history of a droplet is strongly influenced by the presence of the neighboring droplets. Recently, Annamali and Ryan have summarized he current status of droplet array, cloud and spray combustion. A number of simplified theories led numerical studies of droplet vaporization/combustion where multiple droplet effects are present are now available. These theories all neglect the effect of buoyancy. Experimentally, most studies to date suffer the effects of buoyancy. It is the dominant transport mechanism in the problem. Only the works of Law and co-worker and more recently by Mikami et al were performed in an environment where buoyancy effects were small. Law and co-workers were limited to high oxygen index, low pressure ambient environments since there studies were conducted in normal gravity.

Dietrich, Daniel L.↗

Risk of Performance and Behavioral Health Decrements Due to Inadequate Cooperation, Coordination, and Psychosocial Adaptions within a Team

The Risk of Performance and Behavioral Health Decrements Due to Inadequate Cooperation, Coordination, Communication, and Psychosocial Adaptation within a Team (the Team Risk) is primarily performance-focused, with a secondary emphasis on behavioral health outcomes resulting from team performance and interpersonal interactions. Monitoring tools, measures, and countermeasures are aimed at enhancing team processes and team composition configurations to optimize team performance and functioning. Long-duration exploration missions (LDEMs) will include major challenges that could affect team performance, including social isolation, physical confinement, a small and diverse crew, communication delays between crew and ground, limited or no crew rotation or evacuation options, limited or no resupply, and a high-consequence environment. Each of these conditions will affect the crew’s coordination, cooperation, psychological well-being, and performance. Although the International Space Station (ISS) remains important for studies that require spaceflight testing and validation, the current conditions on the ISS do not adequately mimic the exploration environment that is required for National Aeronautics and Space Administration (NASA) teams research, and thus access to terrestrial or ground-based analogs of LDEM conditions is paramount. The emphasis on analogs for research is reflected in this updated evidence review of the Team Risk, and includes data from studies conducted at isolated, confined, extreme (ICE) environments (e.g., Antarctic stations), and from several mission simulation analogs such as the Human Exploration Research Analog (HERA) (HERA Experiment Information Package, 2014), also known as isolated, confined, controlled (ICC) environments. These studies have characterized many team factors regarding LDEMs, and the Team Risk has now matured from risk characterization to focusing more on countermeasure development. Because spaceflight evidence for team-level research is lacking, no reliable data is available to quantify the impact of team-level variables on individual and team-level outcomes during spaceflight missions. Until recently, no systematic attempt had been undertaken to measure the performance effects of team cohesion, team composition, team training, or team-related psychosocial adaptation during spaceflight. The Team Risk is a relatively young research area for NASA, with substantial growth only since the 2000s, and with limited access to spaceflight performance data. As a result, spaceflight evidence is lacking to identify specifically what team composition, level of training, amount of cohesion, or quality of psychosocial adaptation is necessary to reduce the risk of performance errors in space. However, astronaut journals and interviews and reports from spaceflight subject matter experts (SMEs) provide testimonies that team performance during spaceflight is important for mission success and to maintain crew health. Team spaceflight data is now being collected as part of the Spaceflight Standard Measures task (Clement, 2021)—a set of core measurements related to many human spaceflight risks that are collected from astronauts before, during, and after long-duration missions. The team-related standard measures focus on team cohesion, team performance, group living, team climate, and team processes. Collection of standard measures data is ongoing and published data is not yet available. Finally, although spaceflight evidence is lacking, evidence gleaned from ground studies and spaceflight analog studies will help close the gaps outlined in the Team Risk. Ground-based studies provide quantitative evidence for team functioning in ICE environments. Academic research on teams has produced dozens of meta-analyses that can be used to understand the general relationships among team inputs (e.g., team member characteristics and skills, job context), team processes, and emergent states (e.g., coordination, communication, cooperation, cohesion, trust, shared cognition), and team outcomes (e.g., effectiveness, errors, adaptation). Teams are complex, incorporating individual characteristics of team members, but also existing at a level that is greater than the sum of its parts. Therefore, the Team Risk must be integrated with other individual-focused NASA Human Research Program (HRP) risks, including Behavioral Medicine (BMed), Sleep, and Human-Systems Integration Architecture (HSIA), and emerging research indicates more integration may needed between the Team Risk and the physiologically oriented risks. Much of this integration occurs through the Human Systems Risk Board (HSRB). A lack of team functioning may be a stressor in some circumstances, but the team often acts as a countermeasure. For example, support for team leaders and teammates can facilitate individual functioning and encourage psychological and physically healthy behaviors and attitudes. However, more research is needed regarding teams during LDEMs and the remaining gaps in the research are described in the current report.

Lauren Blackwell Landon↗

Shuttle mission plans

Shuttle mission plans recently developed by NASA for the time period 1980-1991 are presented. Standard and optional services, which will be available to users of the Space Transportation System (STS) when it becomes operational in the 1980's, are described. Pricing policies established by NASA to encourage use of the STS by commercial, foreign and other U.S. Government users are explained. The small Self-Contained Payload Program, which will make space flight opportunities available to private citizens and individual experimenters who wish to use the Space Shuttle for investigative research, is discussed.

Visentine, J. T.↗

Modernizing engine displays

The introduction of electronic fuel control to modern turbine engines has a number of advantages, which are related to an increase in engine performance and to a reduction or elimination of the problems associated with high angle of attack engine operation from the surface to 50,000 feet. If the appropriate engine display devices are available to the pilot, the fuel control system can provide a great amount of information. Some of the wealth of information available from modern fuel controls are discussed in this paper. The considered electronic engine control systems in their most recent forms are known as the Full Authority Digital Engine Control (FADEC) and the Digital Electronic Engine Control (DEEC). Attention is given to some details regarding the control systems, typical engine problems, the solution of problems with the aid of displays, engine displays in normal operation, an example display format, a multipage format, flight strategies, and hardware considerations.

Schneider, E. T.↗

LIMS HNO3 data above 5 mbar - Corrections based on simultaneous observations of other species

The Limb Infrared Monitor of the Stratosphere (LIMS) instrument monitored four trace gases (O3, H2O, HNO3, and NO2) and the temperature in the stratosphere and mesosphere. Recently, the seven months LIMS data, including the time from Oct. 25, 1978 to May 29, 1979, have become available to the scientific community. It is pointed out that the measurements are of great use in studying the dynamics and chemistry of the stratosphere. The LIMS HNO3 data appear to show a realistic behavior below 5 mbar, but above 5 mbar, the data appear to be too high. In the present paper, the LIMS HNO3 behavior is discussed, taking into account the reason for the unrealistic appearance of the data. Other LIMS data are used to derive HNO3 above 5 mbar through the intermediate species OH.

Jackman, C. H.↗

Improved isoparametric solid and membrane elements

Improvements that were made to the COSMIC NASTRAN elements CIHEX1 and QDMEM1 are described. These elements are isoparametric representations of solid and membrane elastic behavior. Recent papers by the authors have shown the official COSMIC versions of these elements to be inferior to those available in the MacNeal-Schwendler Corporation (MSC) version of NASTRAN in that they are overly stiff for some loadings. Modifications were made to these elements which reduce the order of integration for shear terms and, for the eight-mode solid element, add additional strain functions. The resulting element formulations give behavior similar to that of the MSC elements. The changes made in the element formulations are discussed and results of test problems are compared with results from the official COSMIC elements and with the MSC elements.

Case, W. R.↗

Deceit: A flexible distributed file system

Deceit, a distributed file system (DFS) being developed at Cornell, focuses on flexible file semantics in relation to efficiency, scalability, and reliability. Deceit servers are interchangeable and collectively provide the illusion of a single, large server machine to any clients of the Deceit service. Non-volatile replicas of each file are stored on a subset of the file servers. The user is able to set parameters on a file to achieve different levels of availability, performance, and one-copy serializability. Deceit also supports a file version control mechanism. In contrast with many recent DFS efforts, Deceit can behave like a plain Sun Network File System (NFS) server and can be used by any NFS client without modifying any client software. The current Deceit prototype uses the ISIS Distributed Programming Environment for all communication and process group management, an approach that reduces system complexity and increases system robustness.

Siegel, Alex↗

Applied high-speed imaging for the icing research program at NASA Lewis Research Center

The Icing Research Tunnel at NASA Lewis Research Center provides scientists a scaled, controlled environment to simulate natural icing events. The closed-loop, low speed, refrigerated wind tunnel offers the experimental capability to test for icing certification requirements, analytical model validation and calibration techniques, cloud physics instrumentation refinement, advanced ice protection systems, and rotorcraft icing methodology development. The test procedures for these objectives all require a high degree of visual documentation, both in real-time data acquisition and post-test image processing. Information is provided to scientific, technical, and industrial imaging specialists as well as to research personnel about the high-speed and conventional imaging systems will be on the recent ice protection technology program. Various imaging examples for some of the tests are presented. Additional imaging examples are available from the NASA Lewis Research Center's Photographic and Printing Branch.

Slater, Howard↗

Applied high-speed imaging for the icing research program at NASA Lewis Research Center

The Icing Research Tunnel at NASA Lewis Research Center provides scientists a scaled, controlled environment to simulate natural icing events. The closed-loop, low speed, refrigerated wind tunnel offers the experimental capability to test for icing certification requirements, analytical model validation and calibration techniques, cloud physics instrumentation refinement, advanced ice protection systems, and rotorcraft icing methodology development. The test procedures for these objectives all require a high degree of visual documentation, both in real-time data acquisition and post-test image processing. Information is provided to scientific, technical, and industrial imaging specialists as well as to research personnel about the high-speed and conventional imaging systems will be on the recent ice protection technology program. Various imaging examples for some of the tests are presented. Additional imaging examples are available from the NASA Lewis Research Center's Photographic and Printing Branch.

Slater, Howard↗

Application of CFD in aeronautics at NASA Ames Research Center

The role of Computational Fluid Dynamics (CFD) at Ames Research Center has expanded to address a broad range of aeronautical problems, including wind tunnel support, flight test support, design, and analysis. Balancing the requirements of each new problem against the available resources - software, hardware, time, and expertise - is critical to the effective use of CFD. Several case studies of recent applications highlight the depth of CFD capability at Ames, the tradeoffs involved in various approaches, and lessons learned in the use of CFD as an engineering tool.

Maksymiuk, Catherine M.↗

Remote Sensing of Global Fire Patterns, Aerosol Optical Thickness, and Carbon Monoxide During April 1994

Fires play a crucial role in several ecosystems. They are routinely used to burn forests in order to accommodate the needs of the expanding population, clear land for agricultural purposes, eliminate weeds and pests, regenerate nutrients in grazing and crop lands and produce energy for cooking and heating purposes. Most of the fires on earth are related to biomass burning in the tropics, although they are not confined to these latitudes. The boreal and tundra regions also experience fires on a yearly basis. The current study examines global fire patterns, Aerosol Optical Thickness (AOT) and carbon monoxide concentrations during April 9-19, 1994. Recently, global Advanced Very High Resolution Radiometer (AVHRR) data at nadir ground spatial resolution of 1 km are made available through the NASA/NOAA Pathfinder project. These data from April 9-19, 1994 are used to map fires over the earth. In summary, our analysis shows that fires from biomass burning appear to be the dominant factor for increased tropospheric CO concentrations as measured by the MAPS. The vertical transport of CO by convective activities, along with horizontal transport due to the prevailing winds, are responsible for the observed spatial distribution of CO.

Christopher, Sundar A.↗

Validation of the AMSU-B Bias Corrections Based on Satellite Measurements from SSM/T-2

The NOAA-15 Advanced Microwave Sounding Unit-B (AMSU-B) was designed in the same spirit as the Special Sensor Microwave Water Vapor Profiler (SSM/T-2) on board the DMSP F11-14 satellites, to perform remote sensing of spatial and temporal variations in mid and upper troposphere humidity. While the SSM/T-2 instruments have a 48 km spatial resolution at nadir and 28 beam positions per scan, AMSU-B provides an improvement with a 16 km spatial resolution at nadir and 90 beam positions per scan. The AMSU-B instrument, though, has been experiencing radio frequency interference (RFI) contamination from the NOAA-15 transmitters whose effect is dependent upon channel, geographic location, and current spacecraft antenna configuration. This has lead to large cross-track biases reaching as high as 100 Kelvin for channel 17 (150 GHz) and 50 Kelvin for channel 19 (183 +/-3 GHz). NOAA-NESDIS has recently provided a series of bias corrections for AMSU-B data starting from March, 1999. These corrections are available for each of the five channels, for every third field of view, and for three cycles within an eight second period. There is also a quality indicator in each data record to indicate whether or not the bias corrections should be applied. As a precursor to performing retrievals of mid and upper troposphere humidity, a validation study is performed by statistically analyzing the differences between the F14 SSM/T-2 and the bias corrected AMSU-B brightness temperatures for three months in the spring of 1999.

Kolodner, Marc A.↗

Radiation Effects on Advanced Flash Memories

Flash memories have evolved very rapidly in recent ears. New design techniques such as multilevel storage have been proposed to increase storage density, and are now available commercially. Threshold voltage distributions for single- and three-level technologies are compared. In order to implement this technology special circuitry must be added to allow the amount of charge stored in the floating gate to be controlled within narrow limits during the writing and also to detect the different amounts of charge during reading.

Nguyen, D. N.↗

Non-Invasive Measurement of Intracranial Pressure Pulsation using Ultrasound

Exposure to microgravity causes a cephalad fluid shift which may elevate intracranial pressure (ICP). Elevation in ICP may affect cerebral hemodynamics in astronauts during space flight. ICP is, however, a difficult parameter to measure due to the invasiveness of currently available techniques. We already reported our development of a non-invasive ultrasound device for measurement of ICP. We recently modified the device so that we might reproducibly estimate ICP changes in association with cardiac cycles. In the first experiment, we measured changes in cranial distance with the ultrasound device in cadavera while changing ICP by infusing saline into the lateral ventricle. In the second experiment, we measured changes in cranial distance in five healthy volunteers while placing them in 60 deg, 30 deg head-up tilt, supine, and 10 deg head-down tilt position. In the cadaver study, fast Fourier transformation revealed that cranial pulsation is clearly associated with ICP pulsation. The ratio of cranial distance and ICP pulsation is 1.3microns/mmHg. In the tilting study, the magnitudes of cranial pulsation are linearly correlated to tilt angles (r=0.87). The ultrasound device has sufficient sensitivity to detect cranial pulsation in association with cardiac cycles. By analyzing the magnitude of cranial pulsation, estimates of ICP during space flight are possible.

Ueno, Toshiaki↗