Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “sample environments”

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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Development of a Novel Self-Enclosed Sample Preparation Device for DNA/RNA Isolation in Space

Modern biology techniques present potentials for a wide range of molecular, cellular, and biochemistry applications in space, including detection of infectious pathogens and environmental contaminations, monitoring of drug-resistant microbial and dangerous mutations, identification of new phenotypes of microbial and new life species. However, one of the major technological blockades in enabling these technologies in space is a lack of devices for sample preparation in the space environment. To overcome such an obstacle, we constructed a prototype of a DNA/RNA isolation device based on our novel designs documented in the NASA New Technology Reporting System (MSC-24811-1/3-1). This device is self-enclosed and pipette free, purposely designed for use in the absence of gravity. Our design can also be modified easily for preparing samples in space for other applications, such as flowcytometry, immunostaining, cell separation, sample purification and separation according to its size and charges, sample chemical labeling, and sample purification. The prototype of our DNA/RNA isolation device was tested for efficiencies of DNA and RNA isolation from various cell types for PCR analysis. The purity and integrity of purified DNA and RNA were determined as well. Results showed that our developed DNA/RNA isolation device offers similar efficiency and quality in comparison to the samples prepared using the standard protocol in the laboratory.

Zhang, Ye↗
NASA NTRS1983

Lead isotope systematics of some igneous rocks from the Egyptian Shield

Lead isotope data on whole-rock samples and two feldspar separates for a variety of Pan-African (late Precambrian) igneous rocks for the Egyptian Shield are presented. It is pointed out that the eastern desert of Egypt is a Late Precambrian shield characterized by the widespread occurrence of granitic plutons. The lead isotope ratios may be used to delineate boundaries between Late Precambrian oceanic and continental environments in northeastern Africa. The samples belong to three groups. These groups are related to a younger plutonic sequence of granites and adamellites, a plutonic group consisting of older tonalites to granodiorites, and the Dokhan volcanic suite.

Gillespie, J. G.↗
NASA NTRS2020

Ballooning for Biologists: Mission Essentials for Flying Life Science Experiments to Near Space

Despite centuries of scientific balloon flights, only a handful of experiments have produced biologically-relevant results. Yet unlike orbital spaceflight, it is much faster and cheaper to conduct biology research with balloons, sending specimens to the near space environment of Earth’s stratosphere. Samples can be loaded the morning of a launch and sometimes returned to the laboratory within one day. The National Aeronautics and Space Administration (NASA) flies large, unmanned scientific balloons from all over globe, with missions ranging from hours to weeks in duration. A payload in the middle portion of the stratosphere (~35 km above sea level) will be exposed to an environment similar to the surface of Mars: temperatures as cold as -100 °C, atmospheric pressure at a thin 0.9 kPa, relative humidity levels < 1%, and a harsh illumination of ultraviolet (UV) and cosmic radiation levels (about 100 W/m 2 and 0.07 mGy/d, respectively) that can be obtained nowhere else on the surface of the Earth, including environmental chambers and particle accelerator facilities attempting to simulate space radiation effects. Considering operational advantages of ballooning and the fidelity of space-like stressors in the stratosphere, researchers in aerobiology, astrobiology, and space biology can benefit from balloon flight experiments as an intermediary step on the extraterrestrial continuum (ground, low Earth orbit, and deep space studies). Our review targets biologists with no background or experience in scientific ballooning. We will provide an overview of balloon operations, topics that can be uniquely addressed in the stratosphere, and a roadmap for developing payloads to fly with NASA.

NASA Balloon Program↗
NASA NTRS1978

Technology for return of planetary samples, 1977

Recent progress on the development of a basic warning system (BWS) proposed to assess the biohazard of a Mars sample returned to earth, an earth orbiting spacecraft, or to a moon base was presented. The BWS package consists of terrestrial microorganisms representing major metabolic pathways. A vital processes component of the BWS will examine the effects of a Mars sample at terrestrial atmospheric conditions while a hardy organism component will examine the effects of a Mars sample under conditions approaching those of the Martian environment. Any deleterious insult on terrestrial metabolism effected by the Mars sample could be indicated long before the sample reached earth proximity.

Source record↗
NASA NTRS2026

Contamination Control and Assessment Strategy for Martian Moons Exploration (MMX)

Martian Moons eXploration (MMX) is a sample return mission from the Martian moon Phobos. The MMX spacecraft is scheduled for launch in 2026 and return to Earth in 2031. The primary science objective of MMX is to reveal the origin of the Martian moons, thereby advancing the understanding of planetary system formation and material transport in the solar system, as well as to observe processes affecting the circumplanetary and surface environments of Mars. The returned sample will be transported to the curation facility at ISAS/JAXA, and the subsequent curation and sample analysis activity will be conducted. As a sample return mission, MMX requires strict contamination control to prevent the intrusion of terrestrial materials.

H Sugahara↗
NASA NTRS1977

Volatile products in the corrosion of Cr, Mo, Ti and four superalloys exposed to O2 containing H2O and gaseous NaCl

Cooled target collection techniques were used to study the formation of volatile products when samples of Cr, Ti, IN-738, 713C, NASA-TRW VIA and B-1900 were exposed, at elevated temperatures, to oxidizing environments containing H2O(g) and NaCl(g). Samples were heated to 1050 C in one atmosphere of slowly flowing oxygen, saturated with water at 21 C, and containing about 50 ppm NaCl(g). Volatile products were detected for all materials except B-1900 and Ti. High pressure mass spectrometric sampling was used to directly identify volatile products emanating from samples of Cr and IN-738 subject to the above environments.

Fryburg, G. C.↗
NASA NTRS2003

High Voltage Solar Array ARC Testing for a Direct Drive Hall Effect Thruster System

The deleterious effects of spacecraft charging are well known, particularly when the charging leads to arc events. The damage that results from arcing can severely reduce system lifetime and even cause critical system failures. On a primary spacecraft system such as a solar array, there is very little tolerance for arcing. Motivated by these concerns, an experimental investigation was undertaken to determine arc thresholds for a high voltage (200-500 V) solar array in a plasma environment. The investigation was in support of a NASA program to develop a Direct Drive Hall-Effect Thruster (112HET) system. By directly coupling the solar array to a Hall-effect thruster, the D2HET program seeks to reduce mass, cost and complexity commonly associated with the power processing in conventional power systems. In the investigation, multiple solar array technologies and configurations were tested. The cell samples were biased to a negative voltage, with an applied potential difference between them, to imitate possible scenarios in solar array strings that could lead to damaging arcs. The samples were tested in an environment that emulated a low-energy, HET-induced plasma. Short duration "trigger" arcs as well as long duration "sustained" arcs were generated. Typical current and voltage waveforms associated with the arc events are presented. Arc thresholds are also defined in terms of vo!tage, (current and power. The data will be used to propose a new, high-voltage (>300 V) solar array design for which the likelihood of damage from arcing is minimal.

Schneider, T.↗
NASA NTRS2004

High Voltage Solar Array Arc Testing for a Direct Drive Hall Effect Thruster System

The deleterious effects of spacecraft charging are well known, particularly when the charging leads to arc events. The damage that results from arcing can severely reduce system lifetime and even cause critical system failures. On a primary spacecraft system such as a solar array, there is very little tolerance for arcing. Motivated by these concerns, an experimental investigation was undertaken to determine arc thresholds for a high voltage (200-500 V) solar array in a plasma environment. The investigation was in support of a NASA program to develop a Direct Drive Hall-Effect Thruster (D2HET) system. By directly coupling the solar array to a Hall-effect thruster, the D2HET program seeks to reduce mass, cost and complexity commonly associated with the power processing in conventional power systems. In the investigation, multiple solar array technologies and configurations were tested. The cell samples were biased to a negative voltage, with an applied potential difference between them, to imitate possible scenarios in solar array strings that could lead to damaging arcs. The samples were tested in an environment that emulated a low-energy, HET-induced plasma. Short duration trigger arcs as well as long duration sustained arcs were generated. Typical current and voltage waveforms associated with the arc events are presented. Arc thresholds are also defined in terms of voltage, current and power. The data will be used to propose a new, high-voltage (greater than 300 V) solar array design for which the likelihood of damage from arcing is minimal.

Schneider, Todd↗
DOE OSTI2023

Deep reinforcement learning for class imbalance fault diagnosis of equipment in nuclear power plants

In equipment fault diagnosis in nuclear power plants, there may be far more samples in one class (e.g., a health state) than in another class (e.g., a fault state). The distribution of data in each class is highly skewed. Most machine learning algorithms are suitable for balanced training datasets. When faced with imbalanced samples, these algorithms tend to provide good identification for the majority classes and bias for the minority classes. However, the misclassification of minority classes can lead to high costs. To address the above problem, this paper develops a deep reinforcement learning-based diagnosis method that models fault diagnosis as a sequential decision-making process. At each time step, the agent receives the state of the environment represented by the training samples and then takes a diagnosis action guided by a policy. If the action is correct/incorrect, the agent receives a positive/negative reward. The reward for minority classes is higher than that for majority classes. The agent’s goal is to obtain as many cumulative rewards as possible in the process, i.e., to identify the sample as correctly as possible. Six demonstration scenarios are constructed, depending on the selected fault datasets and the designed model structures. Experiments show that the proposed method achieves a higher weighted-averaged F1 score than the classical supervised learning method in most cases of class imbalance. Finally, the proposed method has potential applications in the field of class imbalance fault diagnosis of equipment in nuclear power plants.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
NASA NTRS1992

Intensified array camera imaging of solid surface combustion aboard the NASA Learjet

An intensified array camera was used to image weakly luminous flames spreading over thermally thin paper samples in a low gravity environment aboard the NASA-Lewis Learjet. The aircraft offers 10 to 20 sec of reduced gravity during execution of a Keplerian trajectory and allows the use of instrumentation that is delicate or requires higher electrical power than is available in drop towers. The intensified array camera is a charge intensified device type that responds to light between 400 and 900 nm and has a minimum sensitivity of 10(exp 6) footcandles. The paper sample, either ashless filter paper or a lab wiper, burns inside a sealed chamber which is filled with 21, 18, or 15 pct. oxygen in nitrogen at one atmosphere. The camera views the edge of the paper and its output is recorded on videotape. Flame positions are measured every 0.1 sec to calculate flame spread rates. Comparisons with drop tower data indicate that the flame shapes and spread rates are affected by the residual g level in the aircraft.

Weiland, Karen J.↗
DOE OSTI2023

Galaxy Interactions in Filaments and Sheets: Effects of the Large-scale Structures Versus the Local Density

Abstract Major interactions are known to trigger star formation in galaxies and alter their color. We study the major interactions in filaments and sheets using SDSS data to understand the influence of large-scale environments on galaxy interactions. We identify the galaxies in filaments and sheets using the local dimension and also find the major pairs residing in these environments. The star formation rate (SFR) and color of the interacting galaxies as a function of pair separation are separately analyzed in filaments and sheets. The analysis is repeated for three volume limited samples covering different magnitude ranges. The major pairs residing in the filaments show a significantly higher SFR and bluer color than those residing in the sheets up to the projected pair separation of ∼50 kpc. We observe a complete reversal of this behavior for both the SFR and color of the galaxy pairs having a projected separation larger than 50 kpc. Some earlier studies report that the galaxy pairs align with the filament axis. Such alignment inside filaments indicates anisotropic accretion that may cause these differences. We do not observe these trends in the brighter galaxy samples. The pairs in filaments and sheets from the brighter galaxy samples trace relatively denser regions in these environments. The absence of these trends in the brighter samples may be explained by the dominant effect of the local density over the effects of the large-scale environment.

Astronomy & Astrophysics↗
DOE OSTI2020

The Nature and State of Groundwater Contamination at the Nevada National Security Site: What Have We Learned from Decades of Groundwater Analysis? - 20337

The regulatory framework for remediating radionuclide contamination from underground nuclear testing at the Nevada National Security Site (NNSS) is based on a combination of characterization and modeling studies, monitoring, and institutional controls [1]. Currently, tritium is the largest contributor (∼90%) to the estimated 44.6 million-curie radionuclide inventory resulting from underground testing [2]. Because of its short half-life (12.32 years), its relative contribution reduces below 10% of the total radiologic inventory over the next 120 years as a result of radioactive decay. Although tritium levels are observed well above the Safe Drinking Water Act (SDWA) maximum contaminant levels (MCLs) in groundwater, other radionuclides are well below their MCLs except within the nuclear test near-field (nuclear test cavity and chimney) environment. In fact, most device-derived radionuclides are below their MCL in groundwater even in samples collected from this near-field environment. The distribution of radionuclides following the nuclear detonation greatly influences the availability of potential contaminants for groundwater transport. Tritium is initially distributed in the gas phase, later as tritiated water in steam, and finally as liquid water, and is available to groundwater transport away from the near-field environment. Other radionuclides that are mobile in groundwater are {sup 14}C, {sup 36}Cl, {sup 99}Tc, and {sup 129}I though their radiologic inventory is small when compared to tritium. Many radionuclides (e.g. U, Pu, Am) are incorporated to a significant extent into the melt glass at the bottom of the cavity and are accessible to groundwater primarily through the slow process of glass dissolution. These radionuclides are also adsorbed to the surfaces of the crushed rock within the cavity and chimney which limits their migration in groundwater. Although colloid facilitated transport of radionuclides at the NNSS has been observed [3], radionuclide concentrations decrease with time and migration distances due to desorption and colloid filtration processes. Current studies indicate that radionuclides associated with colloids are unlikely to migrate downgradient from NNSS underground nuclear tests at concentrations above the SDWA MCL [4][5]. The results of over 50 years of sampling, along with an understanding of these post detonation processes, indicate that tritium is the only contaminant of concern downgradient of testing and that even tritium will not exceed its MCL in groundwater after ∼120 years. Although other longer-lived radionuclides may continue to be released slowly from the near-field environment they will likely never reach levels exceeding their MCLs in groundwater downgradient of the NNSS. Groundwater monitoring will continue to verify these observations. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2024

Contamination Results of MISSE 8 Wake and Nadir Samples After 2 Years of Space Exposure on the International Space Station

Spacecraft in low Earth orbit (LEO) are subjected to harsh environmental conditions, including radiation (cosmic rays, ultraviolet, x-ray and charged particle radiation), micrometeoroids and orbital debris, temperature extremes, thermal cycling, and atomic oxygen. In addition, on-orbit spacecraft contamination is a serious spaceflight issue, with silicone contamination being a particular concern. In an effort to understand on-orbit contamination of Materials International Space Station Experiment 8 (MISSE 8) flight samples and other International Space Station (ISS) payloads, contamination studies were conducted post-flight on retrieved Teflon fluorinated ethylene propylene (FEP) samples flown in the wake and nadir orientations on MISSE 8. The wake sample was Teflon FEP (M8-W11) flown as part of the Glenn MISSE 8 Polymers Experiment on the Optical Reflector Materials Experiment-III Ram/Wake (ORMatE-III R/W) tray and exposed to the LEO wake environment for 2.0 years. The nadir samples were silver-Teflon FEP radiator pieces taken from the MISSE 8 Single Events Upset Xilinx-Sandia Experiment II (SEUXSE II) Power Box and exposed to the LEO nadir environment for 2.14 years. The Teflon FEP flight materials were analyzed for changes in surface morphology and chemistry as compared to pristine control samples. The wake samples were also analyzed for changes in optical properties. There was no evidence of a molecular contamination layer present on the surface of the MISSE 8 wake or nadir facing Teflon FEP flight samples, although both the wake and nadir flight samples contained particulate contamination in some regions. The analyzed nadir particles were primarily zinc rich. The majority of analyzed wake particles were comprised of oxidized aluminum with small amounts of zinc and magnesium. The wake particles appear to have arrived early in the mission (or pre-flight) during a single event. This paper provides details of the MISSE 8 sample contamination analyses.

Erosion↗
NASA NTRSDate not supplied

Ground Testing of the MISSE-16 Materials

The harsh space environment imposes very stringent requirements upon spacecraft materials, especially those located on exterior surfaces of space objects in low Earth orbit (LEO). As humankind moves from space exploration to space commercialization, these materials may have to last for 15–20 years without considerable degradation of their optical, electrical, mechanical, and thermal properties. Operational requirements dictate that these materials continue to function according to expectations. Hence, we must understand the effects of the space environment on materials currently in use as well as on untested materials. For the years, the Materials International Space Station Experiment Flight Facility (MISSE-FF) have flown many different materials to investigate the effect of LEO space weather exposure on the performance and durability of materials and devices. The MISSE-16 scientific team members plan to launch fifteen different novel and well-characterized spacecraft-relevant materials to the LEO environment for a duration of six months during the MISSE-16 mission. Changes in spectral reflectivity will be measured throughout the mission as the samples are exposed to the space environment. The same chemical damage the produces changes in optical reflectance also causes changes in numerous other physical properties such as electrical conductivity, mechanical strength, and chemical reactivity. Correlation of the changes in each of these properties as a function of radiation type, flux, and fluence allows various material properties to be inferred from one experimentally tractable measurement: color change. Flying identical test fixtures on the ram, zenith, and wake positions of the MISSE-FF, collecting spectrally resolved images of the materials, and concomitantly measuring the ambient space environment allows deconvolution of the material effects which occur as a result of exposure to neutral atomic oxygen (AO), unfiltered solar ultraviolet (UV) radiation, and electrons. The flight experiment will function as a ground truth reference for our team’s ongoing laboratory-based space weather-material interactions experiments. Comparison of the MISSE-16 data with extensive testing of “flight-duplicate” samples under simulated space weather conditions will enable development of chemical models for prediction of material degradation. This paper discusses preliminary results from the ground test campaign including measurements of UV/VIS/IR reflectance spectra, bidirectional reflectance distribution function (BRDF), surface potential decay, and surface morphology under electron and AO exposure.

Elena A. Plis↗
NASA NTRS2007

Liquid Metering Centrifuge Sticks (LMCS): A Centrifugal Approach to Metering Known Sample Volumes for Colorimetric Solid Phase Extraction (C-SPE)

Phase separation is one of the most significant obstacles encountered during the development of analytical methods for water quality monitoring in spacecraft environments. Removing air bubbles from water samples prior to analysis is a routine task on earth; however, in the absence of gravity, this routine task becomes extremely difficult. This paper details the development and initial ground testing of liquid metering centrifuge sticks (LMCS), devices designed to collect and meter a known volume of bubble-free water in microgravity. The LMCS uses centrifugal force to eliminate entrapped air and reproducibly meter liquid sample volumes for analysis with Colorimetric Solid Phase Extraction (C-SPE). C-SPE is a sorption-spectrophotometric platform that is being developed as a potential spacecraft water quality monitoring system. C-SPE utilizes solid phase extraction membranes impregnated with analyte-specific colorimetric reagents to concentrate and complex target analytes in spacecraft water samples. The mass of analyte extracted from the water sample is determined using diffuse reflectance (DR) data collected from the membrane surface and an analyte-specific calibration curve. The analyte concentration can then be calculated from the mass of extracted analyte and the volume of the sample analyzed. Previous flight experiments conducted in microgravity conditions aboard the NASA KC-135 aircraft demonstrated that the inability to collect and meter a known volume of water using a syringe was a limiting factor in the accuracy of C-SPE measurements. Herein, results obtained from ground based C-SPE experiments using ionic silver as a test analyte and either the LMCS or syringes for sample metering are compared to evaluate the performance of the LMCS. These results indicate very good agreement between the two sample metering methods and clearly illustrate the potential of utilizing centrifugal forces to achieve phase separation and metering of water samples in microgravity.

Gazda, Daniel B.↗
NASA NTRS1992

Effects of long term exposure on optical substrates and coatings (SOO50-2)

Kodak included 12 substrate and coating samples on the Long Duration Exposure Facility (LDEF) structure. There were 3 fused silica and 3 ultra low expansion (ULE(tm)) uncoated glass samples, 2 ULE(tm) samples with a high reflectance silver coating, 2 fused silica samples with an antireflectance coating, and 2 fused silica samples with a solar rejection coating. The sample dimensions were 32 mm diameter by 1 mm thick. A set of duplicate control samples was also manufactured and stored in a controlled environment for comparison purposes. A preliminary evaluation of the flight samples for effects from the 5 year mission showed that a contaminant was deposited on the samples, a micrometeroid impact occurred on one of the samples, and the radiation darkening which was expected for the glass did not occur. The results are presented in more detail.

John Vallimont↗
NASA NTRSDate not supplied

Developing Mass Spectrometry for Water Quantitation and Volatiles Analysis from In-Situ Regolith

With a revived focus to create a sustainable hu-man presence on the moon, and in preparation for future Mars exploration, it is imperative that all resources are utilized to their fullest potential [1]. In-Situ Resource Utilization (ISRU) will be critical for future mission success as it would enable in-dependent operation of missions while reducing the dependence on the complex supply chain created between the Earth, the moon and Mars. One of the most critical resources that has been identified for ISRU on the lunar surface is water [2]. Water is a versatile resource that can be used in various space operations, such as ra-diation shielding and conversion to oxygen (O2) for propellant [3,4]. One of the most water rich resources is thought to be within the regolith lo-cated in the permanently shadowed regions (PSR) of the Moon; several upcoming missions, such as PRIME-1 and VIPER, are already sched-uled to confirm this hypothesis [5,6]. However, there are currently no missions planned to quanti-fy the abudance of water at these regions. The quantity of water contained in the ice will inform and help the development of future ISRU plants and operation. Water and other volatile gases can be detect-ed upon controlled heating of icy lunar regolith for an accurate quantification of water. This method is similar to thermogravimetric analysis, which was used to analyze Apollo lunar regolith sam-ples. However, losses via sublimation/evaporation or contamination may have occurred with the samples due to the transit and exposure to the terrestrial environment. Furthermore, water would not be expected for these samples since they were not collected from a PSR. Thus, for more accurate results, icy lunar regolith should be ana-lyzed in situ to provide the most representative composition of both water and other volatile gas-es. The Light Water Analysis and Volatile Extract (LightWAVE) project aims to address this knowledge gap. A system has been developed to collect, heat and analyze evolved gases from lu-nar regolith on the lunar surface. The gases will be analyzed by a modified commercial off the shelf (COTS) residual gas analyzer (RGA) quad-rupole mass spectrometer. Evolved gases from heated regolith samples can be identified by the observed mass-to-charge (m/z) ratios, and the peak intensities correlate to the abundances of the observed gases for quantitation. Therefore, our group is developing a calibration methodology utilizing a COTS RGA to quantitate water from in-situ regolith samples on the lunar surface. The partial pressure of water and ideal gas law will be used to quantify the total water evolved from a regolith sample. Here we present our methodol-ogy for the design and calibration for water quan-titation using a COTS RGA.

Nilab Azim↗
NASA NTRS2005

Cleanroom Robotics: Appropriate Technology for a Sample Receiving Facility?

NASA is currently pursuing a vigorous program that will collect samples from a variety of solar system environments. The Mars Exploration Program is expected to launch spacecraft that are designed to collect samples of martian soil, rocks, and atmosphere and return them to Earth, perhaps as early as 2016. International treaty obligations mandate that NASA conduct such a program in a manner that avoids cross-contamination both Earth and Mars. Because of this requirement, Mars sample curation will require a high degree biosafety, combined with extremely low levels inorganic, organic, and biological contamination.

Bell, M. S.↗