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Combining Discrete Element Modeling, Finite Element Analysis, and Experimental Calibrations for Modeling of Granular Material Systems Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:43:27.000ZThe current state-of-the-art in DEM modeling has two major limitations which must be overcome to ensure that the technique can be useful to NASA engineers and the commercial sector: the computational intensive nature of the software, and the lack of an established methodology to determine the particle properties to best accurately model a given physical system. The proposed work will address both of these limitations. We will look at two approaches to overcome the particle count limitations of DEM: investigate the scaling up of particle size; and combine FEA and DEM to look at problems of densely packed solids. We will explore regimes where DEM and FEA are applicable and establish a coupling methodology that can be further developed during phase II. To address the lack of an established methodology to determine the particle properties to best accurately model a given physical system, we will investigate several small scale experiments that can be used to characterize DEM models. The proposed work will advance the state-of-the-art in DEM. At the end of phase I we will show the feasibility of developing modeling approaches to overcome the main limitations of DEM.
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Robust Optimal Fragmentation and Dispersion of Near-Earth Objects Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:31:30.000Z<p> During the past 2 decades, various concepts for mitigating the impact threats from NEOs have been proposed, but many of these concepts were impractical and not technically credible. In particular, all non-nuclear techniques require mission lead times larger than 10 years. However, for the most probable impact threat with a warning time less than 10 years, the use of high-energy nuclear explosives in space becomes inevitable for proper fragmentation and dispersion of an NEO in a collision course with Earth. However, the existing nuclear subsurface penetrator technology limits the impact velocity to less than 300m/s because higher impact velocities destroy prematurely the detonation electronic equipment. Thus, an innovative space system architecture utilizing high-energy nuclear explosives must be developed for a worst-case intercept mission resulting in relative closing velocities as high as 5-30km/s. An advanced system concept is proposed for nuclear subsurface explosion missions. The concept blends a hypervelocity kinetic-energy impactor with nuclear subsurface explosion, and exploits a 2-body space vehicle consisting of a fore body and an aft body. These 2 spacecraft bodies may be connected by a deployable boom. The fore body provides proper kinetic impact crater conditions for an aft body carrying nuclear explosives to make a deeper penetration into an asteroid body. For such a complex mission architecture design study, non-traditional, multidisciplinary research efforts in the areas of hypervelocity impact dynamics, nuclear explosion modeling, high-temperature thermal shielding, shock-resistant electronic systems, and advanced space system technologies are required. Expanding upon the current research activities, the Iowa State Asteroid Deflection Research Center will develop an innovative, advanced space system architecture that provides the planetary defense capabilities needed to enable a future real space mission more efficient, affordable, and reliable.</p>
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Rapid Electrochemical Detection and Identification of Microbiological and Chemical Contaminants for Manned Spaceflight Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:40:47.000Z<p>A great deal of effort has gone into the development of point-of-use methods to meet the challenge of rapid bacterial identification for both environmental monitoring and clinical applications.&nbsp; Unfortunately, most of the methods developed rely on Preliminary Chain Reaction (PCR) and face inherent limitations because of the requirement for enzymatic components and thermal control.&nbsp; Other methods based on surface plasmon resonance, quartz crystal microbalance, and fluorescence has been reported with good detection limits, but, these methods are immunological and cannot provide genetic-level information.&nbsp; Further, they require labeled markers, complicated fluid handling systems, and sensitive optics that drive up cost and complexity and preclude them from outside the laboratory.&nbsp; Recent work by a group at the University of Toronto has focused on developing an electrochemical platform that combines ultrasensitive detection, straightforward sample processing, and inexpensive components to create a cost-effective, user-friendly device for detection and identification of microorganisms.&nbsp; The platform combines an electrical cell lysis chamber, and electrochemical reporter system, and nanostructured microelectrodes (NMEs) to detect specific nucleic acid sequences.&nbsp; The nucleic acid sequences are unique to a given type of microorganism and can be used to identify the microorganisms present in a sample.</p><p>From the perspective of the anticipated prototype device &nbsp;(Lam, et al. 2012. <em>Polymerase Chain Reaction-Free, Sample-to-Answer Bacterial Detection in 30 Minutes with Integrated Cell Lysis</em>. Anal. Chem. <strong>84(1)</strong>: 21-5), detection of microbial contaminants will begin with a lysis chamber designed to release DNA and RNA from microorganisms present in the sample using ultrasonic or electrochemical technology.&nbsp; The DNA and RNA mixture is then passed into an analysis chamber containing an array of nanostructured microelectrodes (NMEs).&nbsp; The surface of the NMEs will be functionalized with probe molecules for DNA or RNA sequences specific to the bacteria being targeted.&nbsp; Binding of the DNA or RNA to the appropriate detection probe on the NME surface in the presence of an electrochemical reporter system will change the electrochemical properties of the NMEs.&nbsp; A potentiostat is used to measure the current at each individual electrode before and after addition of the DNA and RNA mixture.&nbsp; The difference in current before and after addition of the mixture to the NMEs is compared against a pre-determined threshold to check for the presence of target bacteria in the sample.&nbsp; The process for detection of chemical contaminants is very similar.&nbsp; The lysis chamber would be bypassed and the sample would flow directly into the analysis chamber.&nbsp; The NMEs will be functionalized with molecules to selectively bind the desired targets (analytes) and the change in the electrochemical response of each NME can again be used to detect and quantify the contaminants.&nbsp; Depending on the analyte of interest, it may be possible to directly measure analyte binding on the surface of the NMEs without the use of an electrochemical reporter system. The overall project will focus on optimization of the individual aspects of the detection platform in preparation for construction of a prototype for a flight experiment.&nbsp; The scope of the work in this proposal is limited to characterization and optimization of the lysis step/sample preparation, probe selection, and NME structure.&nbsp; Lysis conditions will be optimized by evaluating parameters associated with the oscillation frequency and lysis time for ultrasonic techniques and applied voltage for the electrochemical techniques.&nbsp; Cell viability, as determined by fluorescent detection of DNA or R
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ESPA Based Secondary Payload Orbit Maneuvering System Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:16:25.000ZBusek proposes to develop an integrated propulsion, power, ACS, (ProPACS) system for micro-spacecraft deployed from the ESPA ring secondary payload ports. The standardized ProPACS system integrates the essential elements needed for highly capable micro-spacecraft bus including; 1) 600 W Hall effect thruster system for primary propulsion, 2) Xe cold gas thrusters for propulsive ACS, 3) articulated solar array, batteries and power management and distribution (PMAD) system with steady state power of 700W available to the payload when propulsion is off and 4) an integral structure that supports the payload and a LightBand separation mechanism for the ESPA ring. The ProPACS can provide over 1,800 m/sec deltaV to a 181 kg spacecraft with a 80kg payload. In Phase 1 ProPACS system architecture design was completed and all major components were identified. Mass, power, data budgets were developed and major interfaces were specified. Phase 2 focus will be on the ProPACS elements with lower TRL to achieve system wide TRL6 at the end of the program. The thruster will be advanced to near flight level, two PMAD systems will be evaluated and one selected and the ProPACS integral structure supporting the payload and separation ring will be designed and built.
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Hall-Effect Thruster Modifications for Dual-Mode Electric Propulsion Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:08:18.000ZThe integrated NASA/DoD electric propulsion objectives are for a specific mass less than 3 kg/kW while demonstrating a throttlable thrust-to-power ratio of 100:1 at a specific impulse of 1,000 sec down to 40:1 at 4,000 sec with an operational lifetime exceeding 20,000 hours. Modern Hall-effect thrusters (HETs) are a proven technology with flight heritage, established manufacturing readiness and testing channels that nearly meet the desired specifications (as shown in Figure 1). However, the major limitation is that HETs fail to achieve all four of objectives simultaneously. This Phase I feasibility study is focused on a proof-of-concept experiment to alleviate the HET dual-mode operational envelope limitation for both high thrust-to-power and high specific impulse. Starfire Industries believes that a &quot;low hanging fruit&quot; modification to HETs exists, and such an improvement would be evolutionary to enable multi-mission EP systems for NASA's Science Mission Directorate and DoD platforms. Towards this end, Starfire has partnered with Aerojet Corporation to rapidly demonstrate feasibility in Phase I through experimental modification to an existing HET system. If results are confirmed, a Phase II design can be driven to yield immediate upgrades for flight-qualified HET systems for near-term payback.
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Ullage Compatible Optical Sensor for Monitoring Safety Significant Malfunctions Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:33:20.000ZSignificant emphasis has been placed on aircraft fuel tank safety following the TWA Flight 800 accident in July 1996. Upon investigation, the National Transportation Safety Board (NTSB) determined that the explosion of the center wing tank (CWT) resulted most likely from ignition of the flammable fuel/air mixture. The growing concern of aircraft fuel tank safety has taken an added dimension in the post 9/11 world where both commercial and military aircrafts are vulnerable to terrorist attacks utilizing MANPADS (MAN-Portable Air Defense Systems), explosives in shoe/socks, and small arms fire. Fuel tanks also need protection from explosions caused by ballistic impact, lightning, and other sources of ignition. In Phase I, InnoSense LLC has demonstrated the feasibility of an all-optical oxygen sensor capable of detecting oxygen at 40,000 feet elevation down to the ambient level. This Phase II proposal discusses how InnoSense LLC would develop a prototype and perform field testing. The project team possesses seventy person-years of optical sensor related hardware and software expertise. InnoSense has attracted $300,000 in Phase III follow-on funding for further engineering. Innosense will deliver the prototype to NASA, complete with software, manuals, and schematics.
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Individualized Stress Detection System Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:10:11.000ZGiven the extended duration of future missions and the isolated, extreme, and confined environments, there is the possibility that stress-related behavioral conditions and mental disorders (DSM-IV-TR) will develop. The overarching goal of this project is to deliver an integrated system that will track physiological signals (heart rate and heart rate variability) and behavioral signals (sleep wake patterns) to detect chronic stress, hyperarousal, and insomnia during space missions. This project will deliver both the sensor hardware and signal processing software needed for the real-time data collection and integration with other behavioral health monitoring systems (e.g., Individualized Fatigue Meter and Individualized Behavioral Health Meter). The result of Phase II will be a system that can be deployed in space analog environments for validation testing and ultimately deployed on ISS to assist astronauts and mission support personnel in the detection of astronaut chronic stress, hyperarousal, and insomnia. The critical need for an Individualized Stress Detection System has been identified as a priority outlined in the BHP IRP Gap BMED2. The Technology Readiness Level at the end of Phase II will be TRL 5.
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Millennium Ecosystem Assessment: MA Population
nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T09:21:29.000ZThe Millennium Ecosystem Assessment: MA Population data sets provide baseline population information as one of the drivers of ecosystem change. The data helped in estimating the magnitude of regional pressures on ecosystems. The MA Population data sets include Gridded Population of the World (GPW) version 3, population grids from the Global Rural-Urban Mapping Project (GRUMP) (alpha version), Global Subnational Infant Mortality Rates (alpha version), and Global Subnational Prevalence of Child Malnutrition (alpha version) data. (Suggested Usage: To preserve access to the original global and regional population data used by the Millennium Ecosystem Assessment (MA) and other related research.)
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Micromechanical Models for Composite NDE and Diagnostics Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:13:55.000ZModern aircraft (and next generation spacecraft) increasingly rely on composite components due to their excellent specific strength and stiffness, as well as improvements in costs and manufacturing quality. However, life management for composites is in its infancy compared to life management for metal structures. Limitations in the ability of standard nondestructive evaluation (NDE) methods to observe manufacturing quality and in-service damage evolution of composite structures may prevent designers from realizing their full potential. Current NDE practices are incapable of overcoming these limitations. Thus, a new framework and methodology is needed for high resolution imaging and tracking of manufacturing quality and damage evolution. The goal of this program is to enable assessment of the matrix, fiber, and bonding conditions for composites using a combination of detailed physics-based models, high resolution imaging, and controlled loading sources to isolate the composite characteristic of interest. Micromechanical models allow quantitative determination of composite constituent properties. This program focuses on magnetic field sensing (i.e., eddy-current) methods that can be combined with structural analysis to enhance the diagnostic capabilities of these NDE methods. JENTEK and MR&D are well-positioned to deliver this methodology in the form of commercial software and NDE equipment. We will also work with a major aircraft OEM to maintain our focus on practical solutions to high priority needs.
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NACP MsTMIP: Global and North American Driver Data for Multi-Model Intercomparison
nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T08:26:40.000ZABSTRACT: This data set provides environmental data that have been standardized and aggregated for use as input to carbon cycle models at global (0.5-degree resolution) and regional (North America at 0.25-degree resolution) scales. The data were compiled from selected sources (Table 2) and integrated into gridded global and regional collections of climatology variables (precipitation, air temperature, air specific humidity, air relative humidity (NA only), pressure, downward longwave radiation, downward shortwave radiation, and wind speed), time-varying atmospheric CO2 concentrations, time-varying nitrogen deposition, biome fraction and type, land-use and land-cover change, C3/C4 grasses fractions, major crop distribution, phenology, multiple soil characteristics, and a land-water mask. The temporal ranges of the data are sufficient for carbon cycle model simulations from 1801 to 2010. These data were compiled specifically for the North American Carbon Program (NACP) Multi-Scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) as the prescribed model input driver data (Huntzinger et al., 2013). The driver data were used by 22 terrestrial biosphere models to run baseline and sensitivity simulations. The standardized data provided consistent model inputs to minimize the inter-model variability caused by differences in environmental drivers and initial conditions. Together with the sensitivity simulations, the standardized input data enable better interpretation and quantification of structural and parameter uncertainties of model estimates. Data are provided in Climate and Forecast (CF) metadata convention compliant (version 1.4) netCDF-4 file formats. There are 3,152 *.nc4 data files with this data set.