NASA Experience with Large and Small UAS for Atmospheric Science

NASA's unmanned aerial systems (UAS) have been utilized in many science missions, going all the way back to 1993. Some of these missions have targeted imagery (fire, vegetation) and surface measurements, but many have been applied to atmospheric research, both physical (dynamics, weather, etc.) and chemical (e.g.,composition). NASA's largest UAS, the Global Hawk, has been used to study atmospheric composition at the tropical tropopause in the Airborne Tropical TRopopause EXperiment (ATTREX) mission, where the benefit of the UAS was long range and especially duration of up to 24 hours. Two Global Hawks were used in the Hurricane and Severe Storm Sentinal (HS3) mission to observe hurricane development. Again, long duration at altitude was the significant feature of the UAS. At the smallest scale, NASA has flown DragonEye UAS to measure volcanic gas emissions in both Costa Rica and Hawaii. The small DragonEye could sample gases in hazardous locations where manned aircraft could not fly. At mid-size, the NASA SIERRA UAS has flown imaging payloads and chemical remote sensing instruments in local and international settings. Theseexperiences provide direction for best use of UAS in atmospheric science, which will be presented

Coupling of dislocations and precipitates: impact on the mechanical behavior of Al 7xxx alloys at the submicron length scale

Reducing length scale on precipitation strengthened aluminum alloys leads to improved strength but reduced ductility and nonuniform elongation. Underlying mechanisms are attributed to the interaction between grain boundaries, dislocations, and precipitates. Recent studies revealed that a high volume fraction of grain boundaries provided sinks for structural defects, i.e., vacancies and dislocations, in ultra-fine grained (UFG) Al 7075, and thus the density of defects is relatively low in grain interiors. As a consequence, the precipitate nucleation mechanism is altered. In an effort to investigate how coupling of dislocations and precipitates affects the mechanical behavior of Al 7xxx alloys at a submicron length scale, it is important to develop and sustain a high density of dislocations in the grain interior via deformation. In this study, nanostructured Al 709x alloy powder was fabricated by cryomilling and was subsequently consolidated to form UFG bulk materials through two different processing routes: one with elevated temperature slow strain rate deformation and the other with room temperature high strain rate (HSR) deformation. The latter provides the opportunity to sustain a high density of dislocations in the grain interiors of UFGs. For comparison purposes, coarse grained (CG) counterparts were fabricated via the same consolidation and deformation processes but using gas-atomized CG powder. Results reveal that the coupling effects between dislocations and precipitates in the HSR deformed UFG lead to extreme high strength (UTS 878 MPa) with uniform elongation. Interestingly, T6 temper decreases the strength of the UFG–HSR sample while it improves the ductility. Detailed microstructural characterization is performed to provide insight into the interaction between structural defect evolution and precipitation phenomenon

Economic analysis of large-scale hydrogen storage for renewable utility applications.

The work reported here supports the efforts of the Market Transformation element of the DOE Fuel Cell Technology Program. The portfolio includes hydrogen technologies, as well as fuel cell technologies. The objective of this work is to model the use of bulk hydrogen storage, integrated with intermittent renewable energy production of hydrogen via electrolysis, used to generate grid-quality electricity. In addition the work determines cost-effective scale and design characteristics and explores potential attractive business models

Processing and Microstructure of WC-CO Cermets by Laser Engineering Net Shaping

Submicron-sized tungsten carbide-cobalt (WC-Co) powder and nanostructured WC-Co powder were applied to make thick wall samples by the Laser Engineered Net Shaping (LENS®) process. It was found that decomposition and decarburization of WC was limited during laser deposition because of the features of the LENS® process: high cooling rate, short heating time, and low oxygen concentration. The effects of working distance, as well as laser power, powder feed rate, and traverse speed on microstructure were studied in this paper. Thermal behavior leading to the observed microstructures that result from the variations in the processing parameters was investigated in detailMechanical Engineerin

Supporting NASA Science with High-Altitude Long-Endurance Aircraft

NASA Earth Science and Aeronautics researchers have been involved in development and use of High Altitude Long Endurance (HALE) unmanned aircraft systems (UAS) since the 1990's. The NASA Environmental Research Aircraft Sensor and Technology Program (ERAST) demonstrated the promise of HALE aircraft for providing observations while also proving the importance of triple-redundant avionics to improve system reliability for large unmanned aircraft. Early efforts to develop an operational HALE capability for earth observations languished for nearly two decades owing to insufficient solar panel efficiency, battery power density, and light-weight, yet strong, materials. During this time NASA researchers focused on using the Global Hawk to demonstrate the utility of providing diurnal measurements over severe storms (ie. HS3) and to track stratospheric water vapor transport (ATTREX). Recent significant commercial investments are now leading to the realization of a long-held goal of week- to month-long sustained observations and measurements from the stratosphere. In addition to a historical review of NASA use and interest in HALE aircraft, this paper will present current concepts for exploiting current and planned HALE aircraft capabilities including in situ characterization of atmospheric composition and dynamics as well as imagery collection. NASA researchers anticipate HALE will provide a useful means to test smallsat instruments and components. Observations from HALE-based instruments might also provide useful gap-filler observations to flagship satellite missions where the repeat time doesn't allow for measurements of quickly changing phenomenon. HALE will likely also provide measurements and communications relay to facilitate other aircraft in multi-aircraft campaigns. We will also report on progress towards a NASA-funded flight test planned for summer 2019 of a solar-electric vehicle designed to carry 7kg (15lbs) for 30 days at 20km altitude

Aluminum with dispersed nanoparticles by laser additive manufacturing.

While laser-printed metals do not tend to match the mechanical properties and thermal stability of conventionally-processed metals, incorporating and dispersing nanoparticles in them should enhance their performance. However, this remains difficult to do during laser additive manufacturing. Here, we show that aluminum reinforced by nanoparticles can be deposited layer-by-layer via laser melting of nanocomposite powders, which enhance the laser absorption by almost one order of magnitude compared to pure aluminum powders. The laser printed nanocomposite delivers a yield strength of up to 1000 MPa, plasticity over 10%, and Young's modulus of approximately 200 GPa, offering one of the highest specific Young's modulus and specific yield strengths among structural metals, as well as an improved specific strength and thermal stability up to 400 °C compared to other aluminum-based materials. The improved performance is attributed to a high density of well-dispersed nanoparticles, strong interfacial bonding between nanoparticles and Al matrix, and ultrafine grain sizes

Enhancing the Safety of Medication Administration: The Synergistic Role of Closed Loop Electronic Medication Management and IV Medication Administration

The high acuity of patients in the ICU results in numerous medications being administered, increasing the risk of medication errors. The purpose of this project is to investigate the impact of integrating consistent closed loop electronic medication management (CLEMM) to decrease medication errors in the ICU for bedside nurses who use electronic health records (EHRs). The project type is a comprehensive literature review, with studies that included a single prospective cohort study, case report, single non-randomized trial, quasi experimental study, single cross-sectional studies, and systematic reviews. The importance of this project is to address the break in the loop of communication between healthcare professionals that consequently lead to medication errors and poor patient outcomes. Multiple databases, specifically CINAHL, PubMed, Medline, and Google Scholar, were utilized to explore the literature. The findings suggest that multiple interventions must be incorporated to decrease the rate of medication errors and reduce patient harm. The findings also show that CLEMM, BCMA, and smart IV pumps are interventions that would be effective in reducing the amount of medication errors made in the ICU setting. While published literature displays the benefits of these implementations, further research must be conducted on the specific communication techniques, breaking all communication barriers in order to reduce the overall percentage of medication errors. Implementing CLEMM framework as well as BCMA in hospitals that use EHRs decreases the rate of medication errors in the ICU and ultimately reduces patient harm. Keywords: Closed loop electronic medication management, barcode medication administration, medication errors, IV smart pumps

Characteristics and Technologies for Long- vs. Short-Term Energy Storage: A Study by the DOE Energy Storage Systems Program

This report describes the results of a study on stationary energy storage technologies for a range of applications that were categorized according to storage duration (discharge time): long or short. The study was funded by the U.S. Department of Energy through the Energy Storage Systems Program. A wide variety of storage technologies were analyzed according to performance capabilities, cost projects, and readiness to serve these many applications, and the advantages and disadvantages of each are presented

Nucleation and growth behavior of multicomponent secondary phases in entropy-stabilized oxides

The rocksalt structured (Co,Cu,Mg,Ni,Zn)O entropy-stabilized oxide (ESO) exhibits a reversible phase transformation that leads to the formation of Cu-rich tenorite and Co-rich spinel secondary phases. Using atom probe tomography, kinetic analysis, and thermodynamic modeling, we uncover the nucleation and growth mechanisms governing the formation of these two secondary phases. We find that these phases do not nucleate directly, but rather they first form Cu-rich and Co-rich precursor phases, which nucleate in regions rich in Cu and cation vacancies, respectively. These precursor phases then grow through cation diffusion and exhibit a rocksalt-like crystal structure. The Cu-rich precursor phase subsequently transforms into the Cu-rich tenorite phase through a structural distortion-based transformation, while the Co-rich precursor phase transforms into the Co-rich spinel phase through a defect-mediated transformation. Further growth of the secondary phases is controlled by cation diffusion within the primary rocksalt phase, whose diffusion behavior resembles other common rocksalt oxides

Long- vs. short-term energy storage technologies analysis : a life-cycle cost study : a study for the DOE energy storage systems program.

This report extends an earlier characterization of long-duration and short-duration energy storage technologies to include life-cycle cost analysis. Energy storage technologies were examined for three application categories--bulk energy storage, distributed generation, and power quality--with significant variations in discharge time and storage capacity. More than 20 different technologies were considered and figures of merit were investigated including capital cost, operation and maintenance, efficiency, parasitic losses, and replacement costs. Results are presented in terms of levelized annual cost, $/kW-yr. The cost of delivered energy, cents/kWh, is also presented for some cases. The major study variable was the duration of storage available for discharge