SEARCH · Engineering Papers

Results for “Mobile Measuring System”

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.

SourceResearch connectionFrom yearThrough year

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

At least 199 records · Page 11

All sources NASA NTRS DOE OSTI

NASA NTRS2019

Testing and Improving a UAV-Based System Designed for Wetland Methane Source Measurements

Wetlands are the single highest emitting methane source category, but the magnitude of wetland fluxes remains difficult to fully characterize due to their large spatial extent and heterogeneity. Fluxes can vary with land surface conditions, vegetation type, and seasonal changes in environmental conditions. Unmanned aerial vehicles (UAVs) are an emerging platform to better characterize spatial variability in these natural ecosystems. While presenting some advantages over traditional techniques like towers and flux chambers, in that they are mobile vertically and horizontally, their use is still challenging, requiring continued improvement in sensor technology and field measurement approaches. In this work, we employ a small, fast response laser spectrometer on a Matrice 600 hexacopter. The system was previously deployed successfully for 40 flights conducted in a four-day period in 2018 near Fairbanks, Alaska. These flights revealed several potential areas for improvement, including: vertical positioning accuracy, the need for sensor health indicators, and approaches to deal with low wind speeds. An additional set of flights was conducted this year near Antioch in California. Flights were conducted several meters above ground up to 15-25 m in a curtain pattern. These curtains were flown both upwind and downwind of a tower site, allowing us to calculate a mass balance methane flux estimate that can be compared to eddy covariance fluxes from the tower. Testing will better characterize the extent to which altitude drifts in-flight and how GPS values compare with measurements from the onboard LIDAR, as well as the agreement between two-dimensional wind speed and direction on the ground versus measured onboard the UAV. Hardware improvements to the sensor and GPS are being considered to help reduce these sources of uncertainty. Results of this testing and how system performance relates to needs for quantifying wetland fluxes, will be presented.

Golston, Levi↗

NASA NTRS1975

Oxygen tank assemblies

Structural design considerations for O2 tank shells and suspension systems of ground based storage and mobile tank systems are outlined. Safety factors, chemical compatibility, liquid slosh strength, and cryogenic temperature properties are summarized. Finally, costs, quality control measures, and long life characteristics are examined.

Source record↗

NASA NTRS1982

Countercurrent distribution of biological cells

Detailed physiochemical studies of dextran/poly(ethylene glycol) (PEG) two phase systems were carried out to characterize and provide understanding of the properties of the systems which determine cell partition and the electrophoretic behavior of phase drops responsible for electric field driven phase separation. A detailed study of the electrostatic and electrokinetic potentials developed in these systems was carried out. The salt partition was examined both in phase systems and with pure polymer solutions via equilibrium dialysis and mechanism of sulfate, chloride and phosphate partition shown to be exclusion by PEG rather than binding by dextran. Salt partition was shown to have a strong effect on the polymer compositions of the phases as well, an effect which produces large changes in the interfacial tension between them. These effects were characterized and the interfacial tension shown to obey a power law with respect to its dependence on the length of the tie line describing the system composition on a phase diagram. The electrostatic potential differences measured via salt bridges were shown to obey thermodynamic predictions. The electrophoretic mobilities measured were utilized to provide a partial test of Levine's incomplete theory of phase drop electrophoresis. The data were consistent with Levine's expression over a limited range of the variables tested.

Brooks, D. E.↗

NASA NTRS1989

The 32-GHz performance of the DSS-14 70-meter antenna: 1989 configuration

The results of preliminary 32 GHz calibrations of the 70 meter antenna at Goldstone are presented. Measurements were done between March and July 1989 using Virgo A and Venus as the primary efficiency calibrators. The flux densites of theses radio sources at 32 GHz are not known with high accuracy, but were extrapolated from calibrated data at lower frequencies. The measured value of efficiency (0.35) agreed closely with the predicted value (0.32), and the results are very repeatable. Flux densities of secondary sources used in the observations were subsequently derived. These measurements were performed using a beamswitching radiometer that employed an uncooled high-electron mobility transistor (HEMT) low-noise amplifier. This system was installed primarily to determine the performance of the antenna in its 1989 configuration, but the experience will also aid in successful future calibration of the Deep Space Network (DSN) at this frequency.

Gatti, M. S.↗

NASA NTRS2012

Verification of Ares I Liftoff Acoustic Environments via the Ares I Scale Model Acoustic Test

The Ares I Scale Model Acoustic Test (ASMAT) program was implemented to verify the predicted Ares I liftoff acoustic environments and to determine the acoustic reduction gained by using an above deck water sound suppression system. The test article included a 5% scale Ares I vehicle model and Mobile Launcher with tower. Acoustic and pressure data were measured by over 200 instruments. The ASMAT results are compared to Ares I-X flight data.

Counter, Douglas↗

NASA NTRS2014

The ISRU Field Tests 2010 and 2012 at Mauna Kea, Hawaii: Results from the Miniaturised Mossbauer Spectrometers Mimos II and Mimos IIA

The 2010 and 2012 In-Situ Resource Utilization Analogue Test (ISRU) [1] on the Mauna Kea volcano in Hawai'i was coordinated by the Northern Centre for Advanced Technology (NORCAT) in collaboration with the Canadian Space Agency (CSA), the German Aerospace Center (DLR), and the National Aeronautics and Space Administration (NASA), through the PISCES program. Several instruments were tested as reference candidates for future analogue testing at the new field test site at the Mauna Kea volcano in Hawai'i. The fine-grained, volcanic nature of the material is a suitable lunar and martian analogue, and can be used to test excavation, site preparation, and resource utilization techniques. The 2010 location Pu'u Hiwahine, a cinder cone located below the summit of Mauna Kea (19deg45'39.29" N, 155deg28'14.56" W) at an elevation of ~2800 m, provides a large number of slopes, rock avalanches, etc. to perform mobility tests, site preparation or resource prospecting. Besides hardware testing of technologies and systems related to resource identification, also in situ science measurements played a significant role in integration of ISRU and science instruments. For the advanced Mössbauer instrument MIMOS IIA, the new detector technologies and electronic components increase sensitivity and performance significantly. In combination with the high energy resolution of the SDD it is possible to perform Xray fluorescence analysis simultaneously to Mössbauer spectroscopy. In addition to the Fe-mineralogy, information on the sample's elemental composition will be gathered. The 2010 and 2012 field campaigns demonstrated that in-situ Mössbauer spectroscopy is an effective tool for both science and feedstock exploration and process monitoring. Engineering tests showed that a compact nickel metal hydride battery provided sufficient power for over 12 hr of continuous operation for the MIMOS instruments.

Klingelhoefer, G.↗

NASA NTRS1985

WRAP-RIB antenna technology development

The wrap-rib deployable antenna concept development is based on a combination of hardware development and testing along with extensive supporting analysis. The proof-of-concept hardware models are large in size so they will address the same basic problems associated with the design fabrication, assembly and test as the full-scale systems which were selected to be 100 meters at the beginning of the program. The hardware evaluation program consists of functional performance tests, design verification tests and analytical model verification tests. Functional testing consists of kinematic deployment, mesh management and verification of mechanical packaging efficiencies. Design verification consists of rib contour precision measurement, rib cross-section variation evaluation, rib materials characterizations and manufacturing imperfections assessment. Analytical model verification and refinement include mesh stiffness measurement, rib static and dynamic testing, mass measurement, and rib cross-section characterization. This concept was considered for a number of potential applications that include mobile communications, VLBI, and aircraft surveillance. In fact, baseline system configurations were developed by JPL, using the appropriate wrap-rib antenna, for all three classes of applications.

Freeland, R. E.↗

NASA NTRS1981

ATS-6 engineering performance report. Volume 5: Propagation experiments

Propagation experiments at 1550 MHz to 1650 MHz are reviewed, including the Integrated L-Band Experiments system and results, and the Mobile L-Band Terminals for Satellite Communication system. Experiments at 4 GHz to 6 GHz are reported, including the Radio Frequency Interferometer Measurements system and results, and Earth station antenna evaluations. Experiments above 10 GHz are discussed, including Comsat and ATS-6 millimeter wave propagation/experiments, and communication ATS-6 version at 20 and 30 GHz.

Wales, R. O.↗

NASA NTRS2016

Results of Outdoor to Indoor Propagation Measurements from 5-32GHz

The demand for wireless services has increased exponentially in the last few years and shows no signs of slowing in the near future. In order for the next generation wireless to provide seamless access, whether the user is indoors or out, a thorough understanding and validation of models describing the impact of building entry loss (BEL) is required. This information is currently lacking and presents a challenge for most system designers. For this reason empirical data is needed to assess the impact of BEL at frequencies that are being explored for future mobile broadband applications This paper present the results of measurements of outdoor-to-indoor propagation from 5-32 GHz in three different buildings. The first is a newer building that is similar in construction to modern residential home. The second is an older commercial office building. The last building is a very new commercial office building built using modern green building techniques. These three buildings allow for the measurement of propagation losses through both modern and older materials; such as glass windows and exterior block and siding. Initial results found that at particular spatial locations the BEL could be less than 1dB or more than 70dB with free space losses discounted (this is likely influenced by multipath). Additionally, it was observed that the PDF distributions of a majority of the measurements trended toward log-normal with means and standard deviations ranging from 8-38dB and 6-14dB, respectively.

building entry loss↗

NASA NTRS1984

Severe storm electricity

Severe storms and lightning were measured with a NASA U2 and ground based facilities, both fixed base and mobile. Aspects of this program are reported. The following results are presented: (1) ground truth measurements of lightning for comparison with those obtained by the U2. These measurements include flash type identification, electric field changes, optical waveforms, and ground strike location; (2) simultaneous extremely low frequency (ELF) waveforms for cloud to ground (CG) flashes; (3) the CG strike location system (LLP) using a combination of mobile laboratory and television video data are assessed; (4) continued development of analog-to-digital conversion techniques for processing lightning data from the U2, mobile laboratory, and NSSL sensors; (5) completion of an all azimuth TV system for CG ground truth; (6) a preliminary analysis of both IC and CG lightning in a mesocyclone; and (7) the finding of a bimodal peak in altitude lightning activity in some storms in the Great Plains and on the east coast. In the forms on the Great Plains, there was a distinct class of flash what forms the upper mode of the distribution. These flashes are smaller horizontal extent, but occur more frequently than flashes in the lower mode of the distribution.

Rust, W. D.↗

NASA NTRS1995

Satellite Ka-band propagation measurements in Florida

Commercial growth of interactive, high data rate communication systems is expected to focus on the use of the Ka-band (20/30 GHz) radio spectrum. The ability to form narrow spot beams and the attendant small diameter antennas are attractive features to designers of mobile aeronautical and ground based satellite communication systems. However, Ka-band is strongly affected by weather, particularly rain, and hence systems designs may require a significant link margin for reliable operations. Perhaps the most stressing area in North America, weatherwise, is the Florida sub-tropical climatic region. As part of the NASA Advanced Communications Technology Satellite (ACTS) propagation measurements program, beacon and radiometer data have been recorded since December 1993 at the University of South Florida (USF), Tampa, Florida.

Helmken, Henry↗

DOE OSTI2026

Specific ion effects on ion transport in charged polymer membranes

Selective separation of like-charged ions is a central challenge in applications such as critical mineral recovery. Electrochemical membrane–based separations offer promising pathways to address this need, but a limited fundamental understanding of ion transport in charged polymer membranes hampers the development of highly selective materials. This study elucidates the role of specific ion effects (SIEs) in ion transport through charged polymer membranes by integrating experimental measurements of ion mobility and in situ ion/ion and ion/water interactions in model charged polymer membranes with results from molecular dynamics simulations on analogous systems. We demonstrate that solvent-mediated ion interactions drive pronounced SIEs within the studied membranes, with the ion softness, i.e., the malleability of ion hydration shells, from hard/soft acid/base (HSAB) theory emerging as a key predictor of transport properties. HSAB theory also explains the observed mechanism of solvent-mediated ion interactions. Our findings offer a mechanistic framework for designing membranes with tailored ion selectivity, potentially enabling efficient separations of chemically similar ions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS1986

Accuracy of Lidar Measurements of the Atmosphere

Report reviews sources of systematic error in laser radar (lidar) measurements of particles in atmosphere. Report applies particularly to stationary pulsed carbon dioxide lidars of type used to measure backscatter from aerosols in troposphere. Provides information for calibrating such systems accurately and consistently and interpreting their data correctly. Also useful in calibrating mobile and airborne lidars, lidars operating at wavelengths other than those of carbon dioxide lasers, and continuouswave lidars.

Kavaya, M. J.↗

NASA NTRS1986

MAPM: A coherent dual CO2 laser DIAL system

The Mobile Atmospheric Pollutant Mapping System (MAPM) is a dual CO2 laser DIAL system with heterodyne detection that is being developed for large distance range resolved measurement of organic solvent vapors and aerosol clouds. The components have been chosen to allow measurements to be made to distances of 6 to 7 km in a period of 20 to 30 s. The major components of the system are listed. MAPM is being integrated into a system and will be tested with several organic solvent gases and vapors in a remotely positioned sample chamber and with a free release of ethylene. Experimental results and system performance are discussed.

Grant, W. B.↗

NASA NTRS2016

COMMIT in 7-SEAS/BASELInE: Operation of and Observations from a Novel, Mobile Laboratory for Measuring In-Situ Properties of Aerosols and Gases

Trace gases and aerosols (particularly biomass-burning aerosols) have important implications for air quality and climate studies in Southeast Asia (SEA). This paper describes the purpose, operation, and datasets collected from NASA Goddard Space Flight Center's (NASA/GSFC) Chemical, Optical, and Microphysical Measurements of In-situ Troposphere (COMMIT) laboratory, a mobile platform designed to measure trace gases and optical/microphysical properties of naturally occurring and anthropogenic aerosols. More importantly, the laboratory houses a specialized humidification system to characterize hygroscopic growth/enhancement, a behavior that affects aerosol properties and cloud-aerosol interactions and is generally underrepresented in the current literature. A summary of the trace gas and optical/microphysical measurements is provided, along with additional detail and analysis of data collected from the hygroscopic system during the 2015 Seven South-East Asian Studies (7-SEAS) field campaign. The results suggest that data from the platform are reliable and will complement future studies of aerosols and air quality in SEA and other regions of interest.

aerosols↗

NASA NTRS2019

Portable Laser Guided Robotic Metrology (PLGRM) System

This paper introduces the new Portable Laser Guided Robotic Metrology (PLGRM) system at the National Aeronautics and Space Administration's (NASA) Glenn Research Center. Previous work used industrial robots in fixed facilities to characterize antennas and required fixtures that do not lend themselves to portable applications. NASA's PLGRM system is designed for in-situ antenna measurements at a remote site.The system consists of a collaborative robot arm mounted on a vertical lift and a laser tracker, each on a mobile base. Together,they enable scanning a surface larger than the robot's reach.To accomplish this, the robot first collects all points within its reach, then the system is moved and the laser tracker is used to relocate the robot before additional points are captured. The PLGRM implementation will be discussed including how safety and planning are combined to effectively characterize antennas.Software defined triggering is a feature, for flexible integration of vector network analyzers and antenna controllers. Lastly, data will be shown to demonstrate system functionality and accuracy.

Slater, Peter A.↗

NASA NTRS2009

Results and Analysis from Space Suit Joint Torque Testing

A space suit s mobility is critical to an astronaut s ability to perform work efficiently. As mobility increases, the astronaut can perform tasks for longer durations with less fatigue. The term mobility, with respect to space suits, is defined in terms of two key components: joint range of motion and joint torque. Individually these measures describe the path which in which a joint travels and the force required to move it through that path. Previous space suits mobility requirements were defined as the collective result of these two measures and verified by the completion of discrete functional tasks. While a valid way to impose mobility requirements, such a method does necessitate a solid understanding of the operational scenarios in which the final suit will be performing. Because the Constellation space suit system requirements are being finalized with a relatively immature concept of operations, the Space Suit Element team elected to define mobility in terms of its constituent parts to increase the likelihood that the future pressure garment will be mobile enough to enable a broad scope of undefined exploration activities. The range of motion requirements were defined by measuring the ranges of motion test subjects achieved while performing a series of joint maximizing tasks in a variety of flight and prototype space suits. The definition of joint torque requirements has proved more elusive. NASA evaluated several different approaches to the problem before deciding to generate requirements based on unmanned joint torque evaluations of six different space suit configurations being articulated through 16 separate joint movements. This paper discusses the experiment design, data analysis and results, and the process used to determine the final values for the Constellation pressure garment joint torque requirements.

Matty, Jennifer E.↗

NASA NTRS1995

High accuracy time transfer synchronization

In July 1994, the U.S. Naval Observatory (USNO) Time Service System Engineering Division conducted a field test to establish a baseline accuracy for two-way satellite time transfer synchronization. Three Hewlett-Packard model 5071 high performance cesium frequency standards were transported from the USNO in Washington, DC to Los Angeles, California in the USNO's mobile earth station. Two-Way Satellite Time Transfer links between the mobile earth station and the USNO were conducted each day of the trip, using the Naval Research Laboratory(NRL) designed spread spectrum modem, built by Allen Osborne Associates(AOA). A Motorola six channel GPS receiver was used to track the location and altitude of the mobile earth station and to provide coordinates for calculating Sagnac corrections for the two-way measurements, and relativistic corrections for the cesium clocks. This paper will discuss the trip, the measurement systems used and the results from the data collected. We will show the accuracy of using two-way satellite time transfer for synchronization and the performance of the three HP 5071 cesium clocks in an operational environment.

Wheeler, Paul J.↗