Analysis and measurements of low frequency lightning component penetration through aerospace vehicle metal and graphite skins

NASA Technical Reports Server (NTRS)

Robb, J. D.; Chen, T.

1980-01-01

An analysis of the shielding properties of mixed metal and graphite composite structures has illustrated some important aspects of electromagnetic field penetration into the interior. These include: (1) that graphite access doors on metallic structures will attenuate lightning magnetic fields very little; conversely, metal doors on a graphite structure will also attenuate fields from lightning strike currents very little, i.e., homogeneity of the shield is a critical factor in shielding and (2) that continuous conductors between two points inside a graphite skin such as an air data probe metallic tubing connection to an air data computer can allow large current penetrations into a vehicle interior. The true weight savings resulting from the use of composite materials can only be evaluated after the resulting electromagnetic problems such as current penetrations have been solved, and this generally requires weight addition in the form of cable shields, conductor bonding or external metallization.

Solvothermal Synthesis of a Hollow Micro-Sphere LiFePO4/C Composite with a Porous Interior Structure as a Cathode Material for Lithium Ion Batteries

PubMed Central

Liu, Yang; Zhang, Jieyu; Li, Ying; Hu, Yemin; Li, Wenxian; Zhu, Mingyuan; Hu, Pengfei; Chou, Shulei; Wang, Guoxiu

2017-01-01

To overcome the low lithium ion diffusion and slow electron transfer, a hollow micro sphere LiFePO4/C cathode material with a porous interior structure was synthesized via a solvothermal method by using ethylene glycol (EG) as the solvent medium and cetyltrimethylammonium bromide (CTAB) as the surfactant. In this strategy, the EG solvent inhibits the growth of the crystals and the CTAB surfactant boots the self-assembly of the primary nanoparticles to form hollow spheres. The resultant carbon-coat LiFePO4/C hollow micro-spheres have a ~300 nm thick shell/wall consisting of aggregated nanoparticles and a porous interior. When used as materials for lithium-ion batteries, the hollow micro spherical LiFePO4/C composite exhibits superior discharge capacity (163 mAh g−1 at 0.1 C), good high-rate discharge capacity (118 mAh g−1 at 10 C), and fine cycling stability (99.2% after 200 cycles at 0.1 C). The good electrochemical performances are attributed to a high rate of ionic/electronic conduction and the high structural stability arising from the nanosized primary particles and the micro-sized hollow spherical structure. PMID:29099814

Vibrations and structureborne noise in space station

NASA Technical Reports Server (NTRS)

Vaicaitis, R.; Lyrintzis, C. S.; Bofilios, D. A.

1987-01-01

Analytical models were developed to predict vibrations and structureborne noise generation of cylindrical and rectangular acoustic enclosures. These models are then used to determine structural vibration levels and interior noise to random point input forces. The guidelines developed could provide preliminary information on acoustical and vibrational environments in space station habitability modules under orbital operations. The structural models include single wall monocoque shell, double wall shell, stiffened orthotropic shell, descretely stiffened flat panels, and a coupled system composed of a cantilever beam structure and a stiffened sidewall. Aluminum and fiber reinforced composite materials are considered for single and double wall shells. The end caps of the cylindrical enclosures are modeled either as single or double wall circular plates. Sound generation in the interior space is calculated by coupling the structural vibrations to the acoustic field in the enclosure. Modal methods and transfer matrix techniques are used to obtain structural vibrations. Parametric studies are performed to determine the sensitivity of interior noise environment to changes in input, geometric and structural conditions.

Reserving Interior Void Space for Volume Change Accommodation: An Example of Cable-Like MWNTs@SnO2@C Composite for Superior Lithium and Sodium Storage.

PubMed

Zhao, Yi; Wei, Chao; Sun, Shengnan; Wang, Luyuan Paul; Xu, Zhichuan J

2015-06-01

Reserving interior void space in the cable-like structure of multiwalled carbon nanotubes-in-SnO 2 -in-carbon layer (MWNTs@SnO 2 @C) is reported for the first time. Such a design enables the structure performing excellent for Li and Na storage, which benefit from the good electrical conductivity of MWNTs and carbon layer as well as the reserved void space to accommodate the volume changes of SnO 2 .

Transport composite fuselage technology: Impact dynamics and acoustic transmission

NASA Technical Reports Server (NTRS)

Jackson, A. C.; Balena, F. J.; Labarge, W. L.; Pei, G.; Pitman, W. A.; Wittlin, G.

1986-01-01

A program was performed to develop and demonstrate the impact dynamics and acoustic transmission technology for a composite fuselage which meets the design requirements of a 1990 large transport aircraft without substantial weight and cost penalties. The program developed the analytical methodology for the prediction of acoustic transmission behavior of advanced composite stiffened shell structures. The methodology predicted that the interior noise level in a composite fuselage due to turbulent boundary layer will be less than in a comparable aluminum fuselage. The verification of these analyses will be performed by NASA Langley Research Center using a composite fuselage shell fabricated by filament winding. The program also developed analytical methodology for the prediction of the impact dynamics behavior of lower fuselage structure constructed with composite materials. Development tests were performed to demonstrate that the composite structure designed to the same operating load requirement can have at least the same energy absorption capability as aluminum structure.

Outgassing on stagnant-lid super-Earths

NASA Astrophysics Data System (ADS)

Dorn, C.; Noack, L.; Rozel, A. B.

2018-06-01

Aims: We explore volcanic CO2-outgassing on purely rocky, stagnant-lid exoplanets of different interior structures, compositions, thermal states, and age. We focus on planets in the mass range of 1-8 M⊕ (Earth masses). We derive scaling laws to quantify first- and second-order influences of these parameters on volcanic outgassing after 4.5 Gyr of evolution. Methods: Given commonly observed astrophysical data of super-Earths, we identify a range of possible interior structures and compositions by employing Bayesian inference modeling. The astrophysical data comprise mass, radius, and bulk compositional constraints; ratios of refractory element abundances are assumed to be similar to stellar ratios. The identified interiors are subsequently used as input for two-dimensional (2D) convection models to study partial melting, depletion, and outgassing rates of CO2. Results: In total, we model depletion and outgassing for an extensive set of more than 2300 different super-Earth cases. We find that there is a mass range for which outgassing is most efficient ( 2-3 M⊕, depending on thermal state) and an upper mass where outgassing becomes very inefficient ( 5-7 M⊕, depending on thermal state). At small masses (below 2-3 M⊕) outgassing positively correlates with planet mass, since it is controlled by mantle volume. At higher masses (above 2-3 M⊕), outgassing decreases with planet mass, which is due to the increasing pressure gradient that limits melting to shallower depths. In summary, depletion and outgassing are mainly influenced by planet mass and thermal state. Interior structure and composition only moderately affect outgassing rates. The majority of outgassing occurs before 4.5 Gyr, especially for planets below 3 M⊕. Conclusions: We conclude that for stagnant-lid planets, (1) compositional and structural properties have secondary influence on outgassing compared to planet mass and thermal state, and (2) confirm that there is a mass range for which outgassing is most efficient and an upper mass limit, above which no significant outgassing can occur. Our predicted trend of CO2-atmospheric masses can be observationally tested for exoplanets. These findings and our provided scaling laws are an important step in order to provide interpretative means for upcoming missions such as JWST and E-ELT, that aim at characterizing exoplanet atmospheres.

Millimeter Wave Holographical Inspection of Honeycomb Composites

NASA Technical Reports Server (NTRS)

Case, J. T.; Kharkovsky, S.; Zoughi, R.; Stefes, G.; Hepburn, Frank L.; Hepburn, Frank L.

2007-01-01

Multi-layered composite structures manufactured with honeycomb, foam or balsa wood cores are finding increasing utility in a variety of aerospace, transportation, and infrastructure applications. Due to the low conductivity and inhomogeneity associated with these composites standard nondestructive testing (NDT) methods are not always capable of inspecting their interior for various defects caused during the manufacturing process or as a result of in-service loading. On the contrary, microwave and millimeter wave NDT methods are well-suited for inspecting these structures since signals at these frequencies readily penetrate through these structures and reflect from different interior boundaries revealing the presence of a wide range of defects such as disbond, delamination, moisture and oil intrusion, impact damage, etc. Millimeter wave frequency spectrum spans 30 GHz - 300 GHz with corresponding wavelengths of 10 - 1 mm. Due to the inherent short wavelengths at these frequencies, one can produce high spatial resolution images of these composites either using real-antenna focused or synthetic-aperture focused methods. In addition, incorporation of swept-frequency in the latter method (i.e., holography) results in high-resolution three-dimensional images. This paper presents the basic steps behind producing such images at millimeter wave frequencies and the results of two honeycomb composite panels are demonstrated at Q-band (33-50 GHz). In addition, these results are compared to previous results using X-ray computed tomography.

Millimeter Wave Holographical Inspection of Honeycomb Composites

NASA Astrophysics Data System (ADS)

Case, J. T.; Kharkovsky, S.; Zoughi, R.; Steffes, G.; Hepburn, F. L.

2008-02-01

Multi-layered composite structures manufactured with honeycomb, foam, or balsa wood cores are finding increasing utility in a variety of aerospace, transportation, and infrastructure applications. Due to the low conductivity and inhomogeneity associated with these composites, standard nondestructive testing (NDT) methods are not always capable of inspecting their interior for various defects caused during the manufacturing process or as a result of in-service loading. On the contrary, microwave and millimeter wave NDT methods are well-suited for inspecting these structures since signals at these frequencies readily penetrate through these structures and reflect from different interior boundaries revealing the presence of a wide range of defects such as isband, delamination, moisture and oil intrusion, impact damage, etc. Millimeter wave frequency spectrum spans 30 GHz-300 GHz with corresponding wavelengths of 10-1 mm. Due to the inherent short wavelengths at these frequencies, one can produce high spatial resolution images of these composites either using real-antenna focused or synthetic-aperture focused methods. In addition, incorporation of swept-frequency in the latter method (i.e., holography) results in high-resolution three-dimensional images. This paper presents the basic steps behind producing such images at millimeter wave frequencies and the results of two honeycomb composite panels are demonstrated at Q-band (33-50 GHz). In addition, these results are compared to previous results using X-ray computed tomography.

Disturbance, succession, and structural development of an upland hardwood forest on the Interior Low Plateau, Tennessee

Treesearch

Justin L. Hart; Merrit M. Cowden; Scott J. Torreano; J. Patrick R. Vestal

2017-01-01

We quantified species composition, stand structure, canopy disturbance history, and Quercus establishment and canopy accession patterns in an upland hardwood forest in Tennessee. The forest established in the mid-1800s and exhibited structural characteristics that were within the range of what has been reported from other late-successional forests...

Saturn PRobe Interior and aTmosphere Explorer (SPRITE)

NASA Technical Reports Server (NTRS)

Simon, Amy; Banfield, D.; Atkinson, D.; Atreya, S.; Brinckerhoff, W.; Colaprete, A.; Coustenis, A.; Fletcher, L.; Guillot, T.; Hofstadter, M.;

Improvements on the interior structure of Mercury expected from geodesy measurements

NASA Astrophysics Data System (ADS)

Rivoldini, A.; van Hoolst, T.; Verhoeven, O.

2008-09-01

ABSTRACT We assess the improvements on the interior structure of Mercury provided by expected data from geodesy experiments to be performed with the MESSENGER and BepiColombo orbiters. The observation of obliquity will allow estimating the moment of inertia, whereas measurements of libration will determine the moment of inertia of the silicate shell (mantle and crust). Tidal measurements will constrain the Love numbers that characterize the response of Mercury to the solar tidal forcing. Here, we construct depth-dependent interior structure models of Mercury for several plausible chemical compositions of the core and of the mantle using recent data on core and mantle materials. In particular we study the core structure for different mantle mineralogies and two different temperature profiles. We investigate the influence of the core light element concentration, temperature, and melting law on core state and inner core size. We compute libration amplitude, obliquity, tidal deformation, and tidal changes in the external potential for our models.

Composite materials for rail transit systems

NASA Technical Reports Server (NTRS)

Griffin, O. Hayden, Jr.; Guerdal, Zafer; Herakovich, Carl T.

1987-01-01

The potential is explored for using composite materials in urban mass transit systems. The emphasis was to identify specific advantages of composite materials in order to determine their actual and potential usage for carbody and guideway structure applications. The literature was reviewed, contacts were made with major domestic system operators, designers, and builders, and an analysis was made of potential composite application to railcar construction. Composites were found to be in use throughout the transit industry, usually in secondary or auxiliary applications such as car interior and nonstructural exterior panels. More recently, considerable activity has been initiated in the area of using composites in the load bearing elements of civil engineering structures such as highway bridges. It is believed that new and improved manufacturing refinements in pultrusion and filament winding will permit the production of beam sections which can be used in guideway structures. The inherent corrosion resistance and low maintenance characteristics of composites should result in lowered maintenance costs over a prolonged life of the structure.

Historical forest structure, composition, and spatial pattern in dry conifer forests of the western Blue Mountains, Oregon

Treesearch

Derek J. Churchill; Gunnar C. Carnwath; Andrew J. Larson; Sean A. Jeronimo

2017-01-01

In frequent-fire forests of the interior Western United States, historical (prefire suppression) conditions are often used as a reference to set management objectives, guide prescriptions, and monitor treatment effectiveness. We quantified the historical size, density, composition, and spatial patterns of dry mixed-conifer forests in the Blue Mountains of Oregon to...

Internal Characteristics of Phobos and Deimos from Spectral Properties and Density: Relationship to Landforms and Comparison with Asteroids

NASA Technical Reports Server (NTRS)

Murchie, S. L.; Fraeman, A. A.; Arvidson, R. E.; Rivkin, A. S.; Morris, R. V.

2013-01-01

Compositional interpretations of new spectral measurements of Phobos and Deimos from Mars Express/OMEGA and MRO/CRISM and density measurements from encounters by multiple spacecraft support refined estimates of the moons' porosity and internal structure. Phobos' estimated macroporosity of 12-20% is consistent with a fractured but coherent interior; Deimos' estimated macroporosity of 23-44% is more consistent with a loosely consolidated interior. These internal differences are reflected in differences in surface morphology: Phobos exhibits a globally coherent pattern of grooves, whereas Deimos has a surface dominated instead by fragmental debris. Comparison with other asteroids .110 km in diameter shows that this correspondence between landforms and inferred internal structure is part of a pervasive pattern: asteroids interpreted to have coherent interiors exhibit pervasive, organized ridge or groove systems, whereas loosely consolidated asteroids have landforms dominated by fragmental debris and/or retain craters >1.3 body radii in diameter suggesting a porous, compressible interior.

Low density bismaleimide-carbon microballoon composites. [aircraft and submarine compartment safety

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A. (Inventor)

1978-01-01

A process is described for constructing for a composite laminate structure which exhibits a high resistance to heat and flame provides safer interior structures for aircraft and submarine compartments. Composite laminate structures are prepared by the bismaleimide resin preimpregnation of a fiberglass cloth to form a face sheet which is bonded with a bismaleimide hot melt adhesive to a porous core structure selected from the group consisting of polyamide paper and bismaleimide-glass fabric which is filled with carbon microballoons. The carbon microballoons are prepared by pyrolyzing phenolic micro-balloons in the presence of nitrogen. A slurry of the carbon microballoons is prepared to fill the porous core structure. The porous core structure and face sheet are bonded to provide panel structures exhibiting increased mechanical capacities and lower oxygen limit values and smoke density values.

Magnetite Equation of State: Implications for Mars' Interior and Magnetization

NASA Astrophysics Data System (ADS)

Gant, P.; Walsh, J.; Lazarz, J. D.; Jacobsen, S. D.; Jurdy, D. M.

2017-12-01

Mars once had a global magnetic field, although it no longer has an active dynamo. Mars Global Surveyor (MGS) unexpectedly measured a strongly magnetized crust. However, the magnetic carrier as well as the nature and depth of magnetization remain unknown. Downward continuation of the surface magnetization suggests the possibility of great depth of magnetization, as much as 100-200 km, far exceeding that of Earth's. The interior composition and structure of Mars remain unknown. Magnetite offers a likely candidate for Martian magnetization. Experiments with magnetite crystals - one naturally-occurring, the other a laboratory-fabricated single domain crystal, determine its equation of state. NASA's upcoming InSight (INterior Exploration using Seismic Investigations, Geodesy, and Heat Transport) mission to Mars will be the first dedicated to study of the Martian interior. It will land in the Elysium Planitia with a 3-component broadband and short period seismometer, heatflow probe, and a magnetometer to monitor the local, atmospheric, and crustal magnetic field. The planned InSight measurements of Martian heatflow will establish its current temperature gradient. The first step in understanding Mars' magnetization requires knowing both temperature and pressure conditions for its interior, along with the equation of state for magnetite - and other possible magnetic minerals. Laboratory experiments with a range of compositions for the Martian interior could provide critical comparisons with the InSight mission's seismic data.

Historical and current forest and range landscapes in the interior Columbia River basin and portions of the Klamath and Great Basins. Part 1: Linking vegetation patterns and landscape vulnerability to potential insect and pathogen disturbances.

Treesearch

Paul F. Hessburg; Bradley G. Smith; Scott D. Kreiter; Craig A. Miller; R. Brion Salter; Cecilia H. McNicoll; Wendel J. Hann

1999-01-01

Management activities of the 20th century, especially fire exclusion, timber harvest, and domestic livestock grazing, have significantly modified vegetation spatial patterns of forests and ranges in the interior Columbia basin. Compositional patterns as well as patterns of living and dead structure have changed. Dramatic change in vital ecosystem processes such as fire...

Bi-Metallic Composite Structures With Designed Internal Residual Stress Field

NASA Technical Reports Server (NTRS)

Brice, Craig A.

2014-01-01

Shape memory alloys (SMA) have a unique ability to recover small amounts of plastic strain through a temperature induced phase change. For these materials, mechanical displacement can be accomplished by heating the structure to induce a phase change, through which some of the plastic strain previously introduced to the structure can be reversed. This paper introduces a concept whereby an SMA phase is incorporated into a conventional alloy matrix in a co-continuous reticulated arrangement forming a bi-metallic composite structure. Through memory activation of the mechanically constrained SMA phase, a controlled residual stress field is developed in the interior of the structure. The presented experimental data show that the memory activation of the SMA composite component significantly changes the residual stress distribution in the overall structure. Designing the structural arrangement of the two phases to produce a controlled residual stress field could be used to create structures that have much improved durability and damage tolerance properties.

Helioseismology.

ERIC Educational Resources Information Center

Leibacher, John W.; And Others

1985-01-01

Helioseismology (similar to geophysicists' study of seismic waves) makes it possible to penetrate the sun's opaque brilliance by measuring surface oscillations. Their pattern and period hold clues to temperature, structure, composition, and dynamics of the sun's interior. Scientists have used data to build models (evolved mathematically) to…

Bark beetles responses to stand structure and prescribed fire at Black Mountain Experimental Forest, California, USA: 5-year data

Treesearch

C.J. Fettig; S.R. McKelvey

2010-01-01

Highly effective fire suppression and selective harvesting of large-diameter, fire-tolerant tree species, such as ponderosa pine (Pinus ponderosa C. Lawson) and Jeffrey pine (P. jeffreyi Balf.), have resulted in substantial changes to the structure and composition of interior ponderosa pine forests. Mechanical thinning and the...

Properties of the moon and its environment from lunar magnetometer measurements

NASA Technical Reports Server (NTRS)

Parkin, C. W.

1976-01-01

Lunar analysis of data from a total of nine lunar magnetometers is described. Results obtained concerning electromagnetic, compositional, and structural properties of the lunar interior are discussed. Specific topics covered include: lunar magnetic permeability and iron abundance; limits on a highly conducting lunar core; lunar electrical conductivity; and internal structure inferred from conductivity and permeability results.

Prediction and Measurement of the Vibration and Acoustic Radiation of Panels Subjected to Acoustic Loading

NASA Technical Reports Server (NTRS)

Turner, Travis L.; Rizzi, Stephen A.

1995-01-01

Interior noise and sonic fatigue are important issues in the development and design of advanced subsonic and supersonic aircraft. Conventional aircraft typically employ passive treatments, such as constrained layer damping and acoustic absorption materials, to reduce the structural response and resulting acoustic levels in the aircraft interior. These techniques require significant addition of mass and only attenuate relatively high frequency noise transmitted through the fuselage. Although structural acoustic coupling is in general very important in the study of aircraft fuselage interior noise, analysis of noise transmission through a panel supported in an infinite rigid baffle (separating two semi-infinite acoustic domains) can be useful in evaluating the effects of active/adaptive materials, complex loading, etc. Recent work has been aimed at developing adaptive and/or active methods of controlling the structural acoustic response of panels to reduce the transmitted noise1. A finite element formulation was recently developed to study the dynamic response of shape memory alloy (SMA) hybrid composite panels (conventional composite panel with embedded SMA fibers) subject to combined acoustic and thermal loads2. Further analysis has been performed to predict the far-field acoustic radiation using the finite element dynamic panel response prediction3. The purpose of the present work is to validate the panel vibration and acoustic radiation prediction methods with baseline experimental results obtained from an isotropic panel, without the effect of SMA.

Etude des defauts apparaissant dans les amenagements interieurs des avions d'affaires

NASA Astrophysics Data System (ADS)

Charette, Emilie

The evolution of the aeronautic industry led to the development of new materials for these high performance applications. Among other examples, composite sandwich structures are increasingly used for interior body panels of business airplanes. These structures are assembled and fixed to the fuselage using metallic inserts bonded inside the sandwich panels with an epoxy resin adhesive. A thin film of wood veneer covers the visible side of interior furniture in order to bring sophistication and esthetic to the interior design. However, due to multiple factors, surface defects frequently appear on the veneered side of the panel where inserts are located. Moreover the defects tend to appear months after the airplane delivery causing costly reparations. The sources of defects can be mechanical ( deformation due to an excessive tightening), chemical (shrinkage of the epoxy adhesive) or the result of hygrothermal exposition. It is therefore important to understand the source of such surface defects and ultimately prevent or control their appearance. The present thesis deals with defects from chemical and hygrothermal sources appearing on the composite panels used on the interior body of business jets after aging. The main objective was to identify and quantify phenomena causing the defects on the interior panels of business planes. This research project is the first part of a project sponsored by CRIAQ and NSERC. The interaction of several materials can lead to various phenomena causing the apparition of surface defects. The project was thus divided into three parts in order to study an increasingly complex problem. the first study deals with the characterization of the different constitutive materials taken separately. This first part focused on thermal, rheological and mechanical aspects of epoxy adhesives. It was shown that the two adhesives used have different mechanical properties and cure kinetic reactions. In addition, the mechanical properties of sandwich composites panels were studied. The second study focused on the analysis of hygrothermal influence on the adhesive and the composite sandwich panels taken separately. Humidity and temperature can have an important effect on the constitutive materials, it is therefore important to know their influence. Finally, the third part deals with the influence of hygrothermal aging on a structure combining all the different materials. Sample panels including fixing zones (insert and resin) were made at the industrial partner's facility according to the industrial procedure. Subsequently, the samples have undergone an accelerated aging. By using deflectometry system, changes in local curvatures with respect to the aging conditions were observed. A correlation between the material characterization results, the aging effects and the surface defect gravity was performed to evaluate the sources and the occurrence of defects. Recommendations have also been made to ensure the project continuity. This project, carried out in an industrial context with the collaboration of Centre de Recherche Industrielle du Quebec ( CRIQ), 3M Canada and the Chaire de recherche sur les composites hautes performances (CCHP) of the department of mechanical engineering of Ecole Polytechnique de Montreal, highlights the importance of the choice of methods and materials in the manufacturing of composite structures.

Structure and Evolution of the Lunar Interior

NASA Technical Reports Server (NTRS)

Andrews-Hanna, J. C.; Weber, R. C.; Ishihara, Y.; Kamata, S.; Keane, J.; Kiefer, W. S.; Matsuyama, I.; Siegler, M.; Warren, P.

2017-01-01

Early in its evolution, the Moon underwent a magma ocean phase leading to its differentiation into a feldspathic crust, cumulate mantle, and iron core. However, far from the simplest view of a uniform plagioclase flotation crust, the present-day crust of the Moon varies greatly in thickness, composition, and physical properties. Recent significant improvements in both data and analysis techniques have yielded fundamental advances in our understanding of the structure and evolution of the lunar interior. The structure of the crust is revealed by gravity, topography, magnetics, seismic, radar, electromagnetic, and VNIR remote sensing data. The mantle structure of the Moon is revealed primarily by seismic and laser ranging data. Together, this data paints a picture of a Moon that is heterogeneous in all directions and across all scales, whose structure is a result of its unique formation, differentiation, and subsequent evolution. This brief review highlights a small number of recent advances in our understanding of lunar structure.

The interior structure of Ceres as revealed by surface topography

NASA Astrophysics Data System (ADS)

Fu, Roger R.; Ermakov, Anton I.; Marchi, Simone; Castillo-Rogez, Julie C.; Raymond, Carol A.; Hager, Bradford H.; Zuber, Maria T.; King, Scott D.; Bland, Michael T.; Cristina De Sanctis, Maria; Preusker, Frank; Park, Ryan S.; Russell, Christopher T.

2017-10-01

Ceres, the largest body in the asteroid belt (940 km diameter), provides a unique opportunity to study the interior structure of a volatile-rich dwarf planet. Variations in a planetary body's subsurface rheology and density affect the rate of topographic relaxation. Preferential attenuation of long wavelength topography (≥150 km) on Ceres suggests that the viscosity of its crust decreases with increasing depth. We present finite element (FE) geodynamical simulations of Ceres to identify the internal structures and compositions that best reproduce its topography as observed by the NASA Dawn mission. We infer that Ceres has a mechanically strong crust with maximum effective viscosity ∼1025 Pa s. Combined with density constraints, this rheology suggests a crustal composition of carbonates or phyllosilicates, water ice, and at least 30 volume percent (vol.%) low-density, high-strength phases most consistent with salt and/or clathrate hydrates. The inference of these crustal materials supports the past existence of a global ocean, consistent with the observed surface composition. Meanwhile, we infer that the uppermost ≥60 km of the silicate-rich mantle is mechanically weak with viscosity <1021 Pa s, suggesting the presence of liquid pore fluids in this region and a low temperature history that avoided igneous differentiation due to late accretion or efficient heat loss through hydrothermal processes.

The interior structure of Ceres as revealed by surface topography

USGS Publications Warehouse

Fu, Roger R.; Ermakov, Anton; Marchi, Simone; Castillo-Rogez, Julie C.; Raymond, Carol A.; Hager, Bradford; Zuber, Maria; King, Scott D.; Bland, Michael T.; De Sanctis, Maria Cristina; Preusker, Frank; Park, Ryan S.; Russell, Christopher T.

2017-01-01

Ceres, the largest body in the asteroid belt (940 km diameter), provides a unique opportunity to study the interior structure of a volatile-rich dwarf planet. Variations in a planetary body's subsurface rheology and density affect the rate of topographic relaxation. Preferential attenuation of long wavelength topography (≥150 km) on Ceres suggests that the viscosity of its crust decreases with increasing depth. We present finite element (FE) geodynamical simulations of Ceres to identify the internal structures and compositions that best reproduce its topography as observed by the NASA Dawn mission. We infer that Ceres has a mechanically strong crust with maximum effective viscosity ∼1025 Pa s. Combined with density constraints, this rheology suggests a crustal composition of carbonates or phyllosilicates, water ice, and at least 30 volume percent (vol.%) low-density, high-strength phases most consistent with salt and/or clathrate hydrates. The inference of these crustal materials supports the past existence of a global ocean, consistent with the observed surface composition. Meanwhile, we infer that the uppermost ≥60 km of the silicate-rich mantle is mechanically weak with viscosity <1021 Pa s, suggesting the presence of liquid pore fluids in this region and a low temperature history that avoided igneous differentiation due to late accretion or efficient heat loss through hydrothermal processes.

Small cell foams containing a modified dense star polymer or dendrimer as a nucleating agent

DOEpatents

Hedstrand, David M.; Tomalia, Donald A.

1995-01-01

A small cell foam having a modified dense star polymer or dendrimer is described. This modified dense star polymer or dendrimer has a highly branched interior of one monomeric composition and an exterior structure of a different monomeric composition capable of providing a hydrophobic outer shell and a particle diameter of from about 5 to about 1,000 nm with a matrix polymer.

Small cell foams containing a modified dense star polymer or dendrimer as a nucleating agent

DOEpatents

Hedstrand, D.M.; Tomalia, D.A.

1995-02-28

A small cell foam having a modified dense star polymer or dendrimer is described. This modified dense star polymer or dendrimer has a highly branched interior of one monomeric composition and an exterior structure of a different monomeric composition capable of providing a hydrophobic outer shell and a particle diameter of from about 5 to about 1,000 nm with a matrix polymer.

Interior structures and tidal heating in the TRAPPIST-1 planets

NASA Astrophysics Data System (ADS)

Barr, Amy C.; Dobos, Vera; Kiss, László L.

2018-05-01

Context. With seven planets, the TRAPPIST-1 system has among the largest number of exoplanets discovered in a single system so far. The system is of astrobiological interest, because three of its planets orbit in the habitable zone of the ultracool M dwarf. Aims: We aim to determine interior structures for each planet and estimate the temperatures of their rock mantles due to a balance between tidal heating and convective heat transport to assess their habitability. We also aim to determine the precision in mass and radius necessary to determine the planets' compositions. Methods: Assuming the planets are composed of uniform-density noncompressible materials (iron, rock, H2O), we determine possible compositional models and interior structures for each planet. We also construct a tidal heat generation model using a single uniform viscosity and rigidity based on each planet's composition. Results: The compositions for planets b, c, d, and e remain uncertain given the error bars on mass and radius. With the exception of TRAPPIST-1c, all have densities low enough to indicate the presence of significant H2O. Planets b and c experience enough heating from planetary tides to maintain magma oceans in their rock mantles; planet c may have surface eruptions of silicate magma, potentially detectable with next-generation instrumentation. Tidal heat fluxes on planets d, e, and f are twenty times higher than Earth's mean heat flow. Conclusions: Planets d and e are the most likely to be habitable. Planet d avoids the runaway greenhouse state if its albedo is ≳0.3. Determining the planet's masses within 0.1-0.5 Earth masses would confirm or rule out the presence of H2O and/or iron. Understanding the geodynamics of ice-rich planets f, g, and h requires more sophisticated modeling that can self-consistently balance heat production and transport in both rock and ice layers.

Wildlife adaptations and management in eastside interior forests with mixed severity fire regimes.

Treesearch

John F. Lehmkuhl

2004-01-01

Little is known about the effects of mixed severity fire on wildlife, but a population viability analysis framework that considers habitat quantity and quality, species life history, and species population structure can be used to analyze management options. Landscape-scale habitat patterns under a mixed severity fire regime are a mosaic of compositional and structural...

The Internal Structure of Jupiter Family Comet Nuclei: The Talps or Layered Pile Model

NASA Astrophysics Data System (ADS)

Belton, Michael J.; Members of theDeep Impact Science Team

2006-09-01

The characteristics of layered structures seen on the nucleus of Tempel 1 in the Deep Impact images, and also seen on Wild 2 and Borrelly are noted. We consider the implications of the hypothesis that such structures are ubiquitous on Jupiter Family Comets and is an essential element of their internal stucture. If correct this hypothesis implies that the internal structure of JFCs are primordial remnants of the early agglomeration phase and that the physical structure of their interiors, except for possible compositional changes, is essentially as it was when they were formed. This hypothesis has implications for their place of origin and their subsequent collisional evolution. Current models of the latter are in conflict with this hypothesis. Possible resolutions of this conflict are noted. A new conceptual model of the interior of a typical JFC called the Talps or "layered pile" model is presented.

Characterization of the Interior Density Structure of Near Earth Objects with Muons

NASA Astrophysics Data System (ADS)

Prettyman, T. H.; Sykes, M. V.; Miller, R. S.; Pinsky, L. S.; Empl, A.; Nolan, M. C.; Koontz, S. L.; Lawrence, D. J.; Mittlefehldt, D. W.; Reddell, B. D.

2015-12-01

Near Earth Objects (NEOs) are a diverse population of short-lived asteroids originating from the main belt and Jupiter family comets. Some have orbits that are easy to access from Earth, making them attractive as targets for science and exploration as well as a potential resource. Some pose a potential impact threat. NEOs have undergone extensive collisional processing, fragmenting and re-accreting to form rubble piles, which may be compositionally heterogeneous (e.g., like 2008 TC3, the precursor to Almahata Sitta). At present, little is known about their interior structure or how these objects are held together. The wide range of inferred NEO macroporosities hint at complex interiors. Information about their density structure would aid in understanding their formation and collisional histories, the risks they pose to human interactions with their surfaces, the constraints on industrial processing of NEO resources, and the selection of hazard mitigation strategies (e.g., kinetic impactor vs nuclear burst). Several methods have been proposed to characterize asteroid interiors, including radar imaging, seismic tomography, and muon imaging (muon radiography and tomography). Of these, only muon imaging has the potential to determine interior density structure, including the relative density of constituent fragments. Muons are produced by galactic cosmic ray showers within the top meter of asteroid surfaces. High-energy muons can traverse large distances through rock with little deflection. Muons transmitted through an Itokawa-sized asteroid can be imaged using a compact hodoscope placed on or near the surface. Challenges include background rejection and correction for variations in muon production with surface density. The former is being addressed by hodoscope design. Surface density variations can be determined via radar or muon limb imaging. The performance of muon imaging is evaluated for prospective NEO interior-mapping missions.

Edge effects and beta diversity in ground and canopy beetle communities of fragmented subtropical forest

PubMed Central

Catterall, Carla P.; Stork, Nigel E.

2018-01-01

Clearing of dry forests globally creates edges between remnant forest and open anthropogenic habitats. We used flight intercept traps to evaluate how forest beetle communities are influenced by distance from such edges, together with vertical height, spatial location, and local vegetation structure, in an urbanising region (Brisbane, Australia). Species composition (but not total abundance or richness) differed greatly between ground and canopy. Species composition also varied strongly among sites at both ground and canopy levels, but almost all other significant effects occurred only at ground level, where: species richness declined from edge to interior; composition differed between positions near edges (<10 m) and interiors (> 50 m); high local canopy cover was associated with greater total abundance and richness and differing composition; and greater distances to the city centre were associated with increased total abundances and altered composition. Analyses of individual indicator species associated with this variation enabled further biological interpretations. A global literature synthesis showed that most spatially well-replicated studies of edge effects on ground-level beetles within forest fragments have likewise found that positions within tens of metres from edges with open anthropogenic habitats had increased species richness and different compositions from forest interior sites, with fewer effects on abundance. Accordingly, negative edge effects will not prevent relatively small compact fragments (if >10–20 ha) from supporting forest-like beetle communities, although indirect consequences of habitat degradation remain a threat. Retention of multiple spatially scattered forest areas will also be important in conserving forest-dependent beetles, given high levels of between-site diversity. PMID:29494680

Edge effects and beta diversity in ground and canopy beetle communities of fragmented subtropical forest.

PubMed

Stone, Marisa J; Catterall, Carla P; Stork, Nigel E

2018-01-01

Clearing of dry forests globally creates edges between remnant forest and open anthropogenic habitats. We used flight intercept traps to evaluate how forest beetle communities are influenced by distance from such edges, together with vertical height, spatial location, and local vegetation structure, in an urbanising region (Brisbane, Australia). Species composition (but not total abundance or richness) differed greatly between ground and canopy. Species composition also varied strongly among sites at both ground and canopy levels, but almost all other significant effects occurred only at ground level, where: species richness declined from edge to interior; composition differed between positions near edges (<10 m) and interiors (> 50 m); high local canopy cover was associated with greater total abundance and richness and differing composition; and greater distances to the city centre were associated with increased total abundances and altered composition. Analyses of individual indicator species associated with this variation enabled further biological interpretations. A global literature synthesis showed that most spatially well-replicated studies of edge effects on ground-level beetles within forest fragments have likewise found that positions within tens of metres from edges with open anthropogenic habitats had increased species richness and different compositions from forest interior sites, with fewer effects on abundance. Accordingly, negative edge effects will not prevent relatively small compact fragments (if >10-20 ha) from supporting forest-like beetle communities, although indirect consequences of habitat degradation remain a threat. Retention of multiple spatially scattered forest areas will also be important in conserving forest-dependent beetles, given high levels of between-site diversity.

Study of noise reduction characteristics of composite fiber-reinforced panels, interior panel configurations, and the application of the tuned damper concept

NASA Technical Reports Server (NTRS)

Lameris, J.; Stevenson, S.; Streeter, B.

1982-01-01

The application of fiber reinforced composite materials, such as graphite epoxy and Kevlar, for secondary or primary structures developing in the commercial airplane industry was investigated. A composite panel program was initiated to study the effects of some of the parameters that affect noise reduction of these panels. The fiber materials and the ply orientation were chosen to be variables in the test program. It was found that increasing the damping characteristics of a structural panel will reduce the vibration amplitudes at resonant frequencies with attendant reductions in sound reduction. Test results for a dynamic absorber, a tuned damper, are presented and evaluated.

Mechanical properties and production quality of hand-layup and vacuum infusion processed hybrid composite materials for GFRP marine structures

NASA Astrophysics Data System (ADS)

Kim, Sang-Young; Shim, Chun Sik; Sturtevant, Caleb; Kim, Dave (Dae-Wook); Song, Ha Cheol

2014-09-01

Glass Fiber Reinforced Plastic (GFRP) structures are primarily manufactured using hand lay-up or vacuum infusion techniques, which are cost-effective for the construction of marine vessels. This paper aims to investigate the mechanical properties and failure mechanisms of the hybrid GFRP composites, formed by applying the hand lay-up processed exterior and the vacuum infusion processed interior layups, providing benefits for structural performance and ease of manufacturing. The hybrid GFRP composites contain one, two, and three vacuum infusion processed layer sets with consistent sets of hand lay-up processed layers. Mechanical properties assessed in this study include tensile, compressive and in-plane shear properties. Hybrid composites with three sets of vacuum infusion layers showed the highest tensile mechanical properties while those with two sets had the highest mechanical properties in compression. The batch homogeneity, for the GFRP fabrication processes, is evaluated using the experimentally obtained mechanical properties

Ceres’ impact craters: probes of near-surface internal structure and composition

NASA Astrophysics Data System (ADS)

Bland, Michael T.; Raymond, Carol; Park, Ryan; Schenk, Paul; McCord, Tom; Reddy, Vishnu; King, Scott; Sykes, Mark; Russell, Chris

2015-11-01

Dawn Framing Camera images of Ceres have revealed the existence of a heavily cratered surface. Shape models derived from these images indicate that most (though not all) large craters are quite deep: up to 6 km for craters larger than 100 km in diameter. The retention of deep craters is not consistent with a simple differentiated internal structure consisting of an outer layer composed solely of pure water ice (covered with a rocky lag) overlying a rocky core. Here we use finite element simulations to show that, for Ceres’ relatively warm surface temperatures, the timescale required to completely flatten a crater 60-km in diameter (or greater) is less than 100 Myr, assuming a relatively pure outer ice layer (for ice grain sizes ≤ 1 cm). Preserving substantial topography requires that the viscosity of Ceres’ outer-most layer (25-50 km thick) is substantially greater than that of pure water ice. A factor of ten increase in viscosity can be achieved by assuming the layer is a 50/50 ice-rock mixture by volume; however, our simulations show that such an increase is insufficient to prevent substantial relaxation over timescales of 1 Gyr. Only particulate volume fractions greater than 50% provide an increase in viscosity sufficient to prevent large-scale, rapid relaxation. Such volume fractions suggest an outer layer composed of frozen soil/regolith (i.e., more rock than ice by volume), a very salt-rich layer, or both. Notably, while most basins appear quite deep, a few relatively shallow basins have been observed (e.g., Coniraya), suggesting that relaxation may be occurring over very long timescales (e.g., 4 Ga), that Ceres’ interior is compositionally and spatial heterogeneous, and/or that temporal evolution of the interior structure and composition has occurred. If these shallow basins are in fact the result of relaxation, it places an upper limit on the viscosity of Ceres’ outer-most interior layer, implying at least some low-viscosity material is present and likely eliminating the possibility of a purely rocky (homogeneous, low density, high porosity) interior.

Fire severity mediates climate-driven shifts in understorey community composition of black spruce stands of interior Alaska

Treesearch

Emily L. Bernhardt; Teresa N. Hollingsworth; F. Stuart Chapin

2011-01-01

Question: How do pre-fire conditions (community composition and environmental characteristics) and climate-driven disturbance characteristics (fire severity) affect post-fire community composition in black spruce stands? Location: Northern boreal forest, interior Alaska. Methods: We compared plant community composition and environmental stand characteristics in 14...

Separation of airborne and structureborne noise radiated by plates constructed of conventional and composite materials with applications for prediction of interior noise paths in propeller driven aircraft. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Mcgary, M. C.

1986-01-01

The anticipated application of advanced turboprop propulsion systems and use of composite materials in primary structure is expected to increase the interior noise of future aircraft to unacceptability high levels. The absence of technically and economically feasible noise source-path diagnostic tools has been a primer obstacle in the development of efficient noise control treatments for propeller driven aircraft. A new diagnostic method which permits the separation and prediction of the fully coherent airborne and structureborne components of the sound radiated by plates or thin shells has been developed. Analytical and experimental studies of the proposed method were performed on plates constructed of both conventional and composite materials. The results of the study indicate that the proposed method can be applied to a variety of aircraft materials, could be used in flight, and has fewer encumbrances than the other diagnostic tools currently available. The study has also revealed that the noise radiation of vibrating plates in the low frequency regime due to combined airborne and structureborne inputs possesses a strong synergistic nature. The large influence of the interaction between the airborne and structureborne terms has been hitherto ignored by researchers of aircraft interior noise problems.

Jupiter's evolution with primordial composition gradients

NASA Astrophysics Data System (ADS)

Vazan, Allona; Helled, Ravit; Guillot, Tristan

2018-02-01

Recent formation and structure models of Jupiter suggest that the planet can have composition gradients and not be fully convective (adiabatic). This possibility directly affects our understanding of Jupiter's bulk composition and origin. In this Letter we present Jupiter's evolution with a primordial structure consisting of a relatively steep heavy-element gradient of 40 M⊕. We show that for a primordial structure with composition gradients, most of the mixing occurs in the outer part of the gradient during the early evolution (several 107 yr), leading to an adiabatic outer envelope (60% of Jupiter's mass). We find that the composition gradient in the deep interior persists, suggesting that 40% of Jupiter's mass can be non-adiabatic with a higher temperature than the one derived from Jupiter's atmospheric properties. The region that can potentially develop layered convection in Jupiter today is estimated to be limited to 10% of the mass. Movies associated to Figs. 1-3 are available at http://https://www.aanda.org

The Exploration Atmospheres Working Group's Report on Space Radiation Shielding Materials

NASA Technical Reports Server (NTRS)

Barghouty, A. F.; Thibeault, S. A.

2006-01-01

This part of Exploration Atmospheres Working Group analyses focuses on the potential use of nonmetallic composites as the interior walls and structural elements exposed to the atmosphere of the spacecraft or habitat. The primary drive to consider nonmetallic, polymer-based composites as an alternative to aluminum structure is due to their superior radiation shielding properties. But as is shown in this analysis, these composites can also be made to combine superior mechanical properties with superior shielding properties. In addition, these composites can be made safe; i.e., with regard to flammability and toxicity, as well as "smart"; i.e., embedded with sensors for the continuous monitoring of material health and conditions. The analysis main conclusions are that (1) smart polymer-based composites are an enabling technology for safe and reliable exploration missions, and (2) an adaptive, synergetic systems approach is required to meet the missions requirements from structure, properties, and processes to crew health and protection for exploration missions.

Imparting Barely Visible Impact Damage to a Stitched Composite Large-Scale Pressure Box

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.; Przekop, Adam

2016-01-01

The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is a concept that was developed by The Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body (HWB) aircraft configuration, which has been a focus of the NASA Environmentally Responsible Aviation Project. The NASA-Boeing structural development for the HWB aircraft culminated in testing of the multi-bay box, which is an 80%-scale representation of the pressurized center-body section. This structure was tested in the NASA Langley Research Center Combined Loads Test System facility. As part of this testing, barely visible impact damage was imparted to the interior and exterior of the test article to demonstrate compliance with a condition representative of the requirements for Category 1 damaged composite structure as defined by the Federal Aviation Regulations. Interior impacts were imparted using an existing spring-loaded impactor, while the exterior impacts were imparted using a newly designed, gravity-driven impactor. This paper describes the impacts to the test article, and the design of the gravitydriven guided-weight impactor. The guided-weight impactor proved to be a very reliable method to impart barely visible impact damage in locations which are not easily accessible for a traditional drop-weight impactor, while at the same time having the capability to be highly configurable for use on other aircraft structures.

Modeling of exoplanets interiors in the framework of future space missions

NASA Astrophysics Data System (ADS)

Brugger, B.; Mousis, O.; Deleuil, M.

2017-12-01

Probing the interior of exoplanets with known masses and radii is possible via the use of models of internal structure. Here we present a model able to handle various planetary compositions, from terrestrial bodies to ocean worlds or carbon-rich planets, and its application to the case of CoRoT-7b. Using the elemental abundances of an exoplanet’s host star, we significantly reduce the degeneracy limiting such models. This further constrains the type and state of material present at the surface, and helps estimating the composition of a secondary atmosphere that could form in these conditions through potential outgassing. Upcoming space missions dedicated to exoplanet characterization, such as PLATO, will provide accurate fundamental parameters of Earth-like planets orbiting in the habitable zone, for which our model is well adapted.

Interior structure and seasonal mass redistribution of Mars from radio tracking of Mars Pathfinder

NASA Technical Reports Server (NTRS)

Folkner, W. M.; Yoder, C. F.; Yuan, D. N.; Standish, E. M.; Preston, R. A.

1997-01-01

Doppler and range measurements to the Mars Pathfinder lander made using its radio communications system have been combined with similar measurements from the Viking landers to estimate improved values of the precession of Mars' pole of rotation and the variation in Mars' rotation rate. The observed precession of -7576 +/- 35 milliarc seconds of angle per year implies a dense core and constrains possible models of interior composition. The estimated annual variation in rotation is in good agreement with a model of seasonal mass exchange of carbon dioxide between the atmosphere and ice caps.

Interior structure and seasonal mass redistribution of Mars from radio tracking of Mars Pathfinder.

PubMed

Folkner, W M; Yoder, C F; Yuan, D N; Standish, E M; Preston, R A

1997-12-05

Doppler and range measurements to the Mars Pathfinder lander made using its radio communications system have been combined with similar measurements from the Viking landers to estimate improved values of the precession of Mars' pole of rotation and the variation in Mars' rotation rate. The observed precession of -7576 +/- 35 milliarc seconds of angle per year implies a dense core and constrains possible models of interior composition. The estimated annual variation in rotation is in good agreement with a model of seasonal mass exchange of carbon dioxide between the atmosphere and ice caps.

Hybrid passive/active damping for robust multivariable acoustic control in composite plates

NASA Astrophysics Data System (ADS)

Veeramani, Sudha; Wereley, Norman M.

1996-05-01

Noise transmission through a flexible kevlar-epoxy composite trim panel into an acoustic cavity or box is studied with the intent of controlling the interior sound fields. A hybrid noise attenuation technique is proposed which uses viscoelastic damping layers in the composite plate for passive attenuation of high frequency noise transmission, and uses piezo-electric patch actuators for active control in the low frequency range. An adaptive feedforward noise control strategy is applied. The passive structural damping augmentation incorporated in the composite plates is also intended to increase stability robustness of the active noise control strategy. A condenser microphone in the interior of the enclosure functions as the error sensor. Three composite plates were experimentally evaluated: one with no damping layer, the second with a 10 mil damping layer, and the third with a 15 mil damping layer. The damping layer was cocured in the kevlar-epoxy trim panels. Damping in the plates was increased from 1.6% for the plate with no damping layer, to 5.9% for the plate with a 15 mil damping layer. In experimental studies, the improved stability robustness of the controller was demonstrated by improved adaptive feedforward control algorithm convergence. A preliminary analytical model is presented that describes the dynamic behavior of a composite panel actuated by piezoelectric actuators bonded to its surface.

High Resolution 3D Radar Imaging of Comet Interiors

NASA Astrophysics Data System (ADS)

Asphaug, E. I.; Gim, Y.; Belton, M.; Brophy, J.; Weissman, P. R.; Heggy, E.

2012-12-01

Knowing the interiors of comets and other primitive bodies is fundamental to our understanding of how planets formed. We have developed a Discovery-class mission formulation, Comet Radar Explorer (CORE), based on the use of previously flown planetary radar sounding techniques, with the goal of obtaining high resolution 3D images of the interior of a small primitive body. We focus on the Jupiter-Family Comets (JFCs) as these are among the most primitive bodies reachable by spacecraft. Scattered in from far beyond Neptune, they are ultimate targets of a cryogenic sample return mission according to the Decadal Survey. Other suitable targets include primitive NEOs, Main Belt Comets, and Jupiter Trojans. The approach is optimal for small icy bodies ~3-20 km diameter with spin periods faster than about 12 hours, since (a) navigation is relatively easy, (b) radar penetration is global for decameter wavelengths, and (c) repeated overlapping ground tracks are obtained. The science mission can be as short as ~1 month for a fast-rotating JFC. Bodies smaller than ~1 km can be globally imaged, but the navigation solutions are less accurate and the relative resolution is coarse. Larger comets are more interesting, but radar signal is unlikely to be reflected from depths greater than ~10 km. So, JFCs are excellent targets for a variety of reasons. We furthermore focus on the use of Solar Electric Propulsion (SEP) to rendezvous shortly after the comet's perihelion. This approach leaves us with ample power for science operations under dormant conditions beyond ~2-3 AU. This leads to a natural mission approach of distant observation, followed by closer inspection, terminated by a dedicated radar mapping orbit. Radar reflections are obtained from a polar orbit about the icy nucleus, which spins underneath. Echoes are obtained from a sounder operating at dual frequencies 5 and 15 MHz, with 1 and 10 MHz bandwidths respectively. The dense network of echoes is used to obtain global 3D images of interior structure to ~20 m, and to map dielectric properties (related to internal composition) to better than 200 m throughout. This is comparable in detail to modern 3D medical ultrasound, although we emphasize that the techniques are somewhat different. An interior mass distribution is obtained through spacecraft tracking, using data acquired during the close, quiet radar orbits. This is aligned with the radar-based images of the interior, and the shape model, to contribute to the multi-dimensional 3D global view. High-resolution visible imaging provides boundary conditions and geologic context to these interior views. An infrared spectroscopy and imaging campaign upon arrival reveals the time-evolving activity of the nucleus and the structure and composition of the inner coma, and the definition of surface units. CORE is designed to obtain a total view of a comet, from the coma to the active and evolving surface to the deep interior. Its primary science goal is to obtain clear images of internal structure and dielectric composition. These will reveal how the comet was formed, what it is made of, and how it 'works'. By making global yet detailed connections from interior to exterior, this knowledge will be an important complement to the Rosetta mission, and will lay the foundation for comet nucleus sample return by revealing the areas of shallow depth to 'bedrock', and relating accessible deposits to their originating provenances within the nucleus.

Federal Aviation Administration Plan for Research, Engineering & Development, 1998.

DTIC Science & Technology

1998-02-01

release rate. • Improved fracture toughness of non-combustible geopolymer composite fire barriers to enable use as interior and secondary composites ...Fire Resistant, Non-Toxic Interior Panels for Evaluation of Heat Release Rate ♦ Improved Fracture Toughness of Non-Combustible Geopolymer Composite ... composites , atmospheric hazards, crash worthiness, fire safety, and forensics capabilities to support accident investigations. Aviation Security R,E&D

Stand and fuel treatments for restoring old-growth ponderosa pine forests in the interior west (Boise Basin Experimental Forest)

Treesearch

Russell T. Graham; Theresa B. Jain

2007-01-01

Fire exclusion, especially in the dry forests (i.e. those dominated or potentially dominated by ponderosa pine) has most often altered tree and shrub composition and structure and, though often overlooked in many locales, the forest floor from conditions that occurred historically (pre-1900).

A POSSIBLE CARBON-RICH INTERIOR IN SUPER-EARTH 55 Cancri e

DOE Office of Scientific and Technical Information (OSTI.GOV)

Madhusudhan, Nikku; Lee, Kanani K. M.; Mousis, Olivier, E-mail: Nikku.Madhusudhan@yale.edu

Terrestrial planets in the solar system, such as the Earth, are oxygen-rich, with silicates and iron being the most common minerals in their interiors. However, the true chemical diversity of rocky planets orbiting other stars is yet unknown. Mass and radius measurements are used to constrain the interior compositions of super-Earths (exoplanets with masses of 1-10 M{sub Circled-Plus }), and are typically interpreted with planetary interior models that assume Earth-centric oxygen-rich compositions. Using such models, the super-Earth 55 Cancri e (mass 8 M{sub Circled-Plus }, radius 2 R{sub Circled-Plus }) has been suggested to bear an interior composition consisting ofmore » Fe, silicates, and an envelope ({approx}> 10% by mass) of supercritical water. We report that the mass and radius of 55 Cancri e can also be explained by a carbon-rich solid interior made of Fe, C, SiC, and/or silicates and without a volatile envelope. While the data allow Fe mass fractions of up to 40%, a wide range of C, SiC, and/or silicate mass fractions are possible. A carbon-rich 55 Cancri e is also plausible if its protoplanetary disk bore the same composition as its host star, which has been reported to be carbon-rich. However, more precise estimates of the stellar elemental abundances and observations of the planetary atmosphere are required to further constrain its interior composition. The possibility of a C-rich interior in 55 Cancri e opens a new regime of geochemistry and geophysics in extraterrestrial rocky planets, compared to terrestrial planets in the solar system.« less

Vibro-Acoustics Modal Testing at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Pappa, Richard S.; Pritchard, Jocelyn I.; Buehrle, Ralph D.

1999-01-01

This paper summarizes on-going modal testing activities at the NASA Langley Research Center for two aircraft fuselage structures: a generic "aluminum testbed cylinder" (ATC) and a Beechcraft Starship fuselage (BSF). Subsequent acoustic tests will measure the interior noise field created by exterior mechanical and acoustic sources. These test results will provide validation databases for interior noise prediction codes on realistic aircraft fuselage structures. The ATC is a 12-ft-long, all-aluminum, scale model assembly. The BSF is a 40-ft-long, all-composite, complete aircraft fuselage. To date, two of seven test configurations of the ATC and all three test configurations of the BSF have been completed. The paper briefly describes the various test configurations, testing procedure, and typical results for frequencies up to 250 Hz.

Piecewise-Constant-Model-Based Interior Tomography Applied to Dentin Tubules

DOE PAGES

He, Peng; Wei, Biao; Wang, Steve; ...

2013-01-01

Dentin is a hierarchically structured biomineralized composite material, and dentin’s tubules are difficult to study in situ. Nano-CT provides the requisite resolution, but the field of view typically contains only a few tubules. Using a plate-like specimen allows reconstruction of a volume containing specific tubules from a number of truncated projections typically collected over an angular range of about 140°, which is practically accessible. Classical computed tomography (CT) theory cannot exactly reconstruct an object only from truncated projections, needless to say a limited angular range. Recently, interior tomography was developed to reconstruct a region-of-interest (ROI) from truncated data in amore » theoretically exact fashion via the total variation (TV) minimization under the condition that the ROI is piecewise constant. In this paper, we employ a TV minimization interior tomography algorithm to reconstruct interior microstructures in dentin from truncated projections over a limited angular range. Compared to the filtered backprojection (FBP) reconstruction, our reconstruction method reduces noise and suppresses artifacts. Volume rendering confirms the merits of our method in terms of preserving the interior microstructure of the dentin specimen.« less

Deep Interior Mission: Imaging the Interior of Near-Earth Asteroids Using Radio Reflection Tomography

NASA Technical Reports Server (NTRS)

Safaeinili, A.; Asphaug, E.; Rodriquez, E.; Gurrola, E.; Belton, M.; Klaasen, K.; Ostro, S.; Plaut, J.; Yeomans, D.

2005-01-01

Near-Earth asteroids are important exploration targets since they provide clues to the evolution of the solar system. They are also of interest since they present a clear danger to Earth. Our mission objective is to image the internal structure of two NEOs using radio reflection tomography (RRT) in order to explore the record of asteroid origin and impact evolution, and to test the fundamental hypothesis that some NEOs are rubble piles rather than consolidated bodies. Our mission s RRT technique is analogous to doing a CAT scan of the asteroid from orbit. Closely sampled radar echoes are processed to yield volumetric maps of mechanical and compositional boundaries, and to measure interior material dielectric properties. The RRT instrument is a radar that operates at 5 and 15 MHz with two 30-m (tip-to-tip) dipole antennas that are used in a cross-dipole configuration. The radar transmitter and receiver electronics have heritage from JPL's MARSIS contribution to Mars Express, and the antenna is similar to systems used in IMAGE and LACE missions. The 5-MHz channel is designed to penetrate greater than 1 km of basaltic rock, and 15-MHz penetrates a few hundred meters or more. In addition to RRT volumetric imaging, we use redundant color cameras to explore the surface expressions of unit boundaries, in order to relate interior radar imaging to what is observable from spacecraft imaging and from Earth. The camera also yields stereo color imaging for geology and RRT-related compositional analysis. Gravity and high fidelity geodesy are used to explore how interior structure is expressed in shape, density, mass distribution and spin. Ion thruster propulsion is utilized by Deep Interior to enable tomographic radar mapping of multiple asteroids. Within the Discovery AO scheduling parameters we identify two targets, S-type 1999 ND43 (approximately 500 m diameter) and V-type 3908 Nyx (approximately 1 km), asteroids whose compositions bracket the diversity of solar system materials that we are likely to encounter, from undifferentiated to highly evolved. The 5-15 MHz radar is capable of probing more primitive bodies (e.g. comets or C-types) that may be available given other launch schedules. 5 MHz radar easily penetrates, with the required SNR , greater than 1 km of basalt (a good analog for Nyx). Basalt has a greater loss tangent than expected for most asteroids, although iron-rich M-types are probably not appropriate targets. 15 MHz radar penetrates the outer approximately 100 m of rocky 1 km asteroids and the deep interiors of comets. Laboratory studies of the most common NE0 materials expected (S-, C- and V-type meteorite analogs) will commence in 2005.

Design of a composite wing extension for a general aviation aircraft

NASA Technical Reports Server (NTRS)

Adney, P. S.; Horn, W. J.

1984-01-01

A composite wing extension was designed for a typical general aviation aircraft to improve lift curve slope, dihedral effect, and lift to drag ratio. Advanced composite materials were used in the design to evaluate their use as primary structural components in general aviation aircraft. Extensive wind tunnel tests were used to evaluate six extension shapes. The extension shape chosen as the best choice was 28 inches long with a total area of 17 square feet. Subsequent flight tests showed the wing extension's predicted aerodynamic improvements to be correct. The structural design of the wing extension consisted of a hybrid laminate carbon core with outer layers of Kevlar - layed up over a foam interior which acted as an internal support. The laminate skin of the wing extension was designed from strength requirements, and the foam core was included to prevent buckling. A joint lap was recommended to attach the wing extension to the main wing structure.

Sound Transmission Through a Curved Honeycomb Composite Panel

NASA Technical Reports Server (NTRS)

Klos, Jacob; Robinson, Jay H.; Buehrle, Ralph D.

2003-01-01

Composite structures are often used in aircraft because of the advantages offered by a high strength to weight ratio. However, the acoustical properties of these light and stiff structures can often be less than desirable resulting in high aircraft interior noise levels. In this paper, measurements and predictions of the transmission loss of a curved honeycomb composite panel are presented. The transmission loss predictions are validated by comparisons to measurements. An assessment of the behavior of the panel is made from the dispersion characteristics of transverse waves propagating in the panel. The speed of transverse waves propagating in the panel is found to be sonic or supersonic over the frequency range from 100 to 5000 Hz. The acoustical benefit of reducing the wave speed for transverse vibration is demonstrated.

Joining and reinforcing a composite bumper beam and a composite crush can for a vehicle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, Elisabeth; Decker, Leland; Armstrong, Dale

A front bumper beam and crush can (FBCC) system is provided for a vehicle. A bumper beam has an interior surface with a plurality of ribs extending therefrom. The ribs and the interior surface are made of a chopped fiber composite and cooperate to engage a crush can. The chopped fiber composite reinforces the engaging surfaces of the crush can and the interior surface of the bumper beam. The crush can has a tubular body made of a continuous fiber composite. The crush can has outwardly-extending flanges at an end spaced away from the bumper beam. The flanges are atmore » least partially provided with a layer of chopped fiber composite to reinforce a joint between the outwardly-extending flange and the vehicle frame.« less

Evaluation of Lightning Induced Effects in a Graphite Composite Fairing Structure

NASA Technical Reports Server (NTRS)

Trout, Dawn H.; Stanley, James E.; Wahid, Parveen F.

2011-01-01

Defining the electromagnetic environment inside a graphite composite fairing due to near-by lightning strikes is of interest to spacecraft developers. This effort develops a transmission-line-matrix (TLM) model with a CST Microstripes to examine induced voltages. on interior wire loops in a composite fairing due to a simulated near-by lightning strike. A physical vehicle-like composite fairing test fixture is constructed to anchor a TLM model in the time domain and a FEKO method of moments model in the frequency domain. Results show that a typical graphite composite fairing provides adequate shielding resulting in a significant reduction in induced voltages on high impedance circuits despite minimal attenuation of peak magnetic fields propagating through space in near-by lightning strike conditions.

Linking rainforest ecophysiology and microclimate through fusion of airborne LiDAR and hyperspectral imagery

Treesearch

Eben N. Broadbent; Angélica M. Almeyda Zambrano; Gregory P. Asner; Christopher B. Field; Brad E. Rosenheim; Ty Kennedy-Bowdoin; David E. Knapp; David Burke; Christian Giardina; Susan Cordell

2014-01-01

We develop and validate a high-resolution three-dimensional model of light and air temperature for a tropical forest interior in Hawaii along an elevation gradient varying greatly in structure but maintaining a consistent species composition. Our microclimate models integrate high-resolution airborne waveform light detection and ranging data (LiDAR) and hyperspectral...

International Lunar Network (ILN) Anchor Nodes

NASA Technical Reports Server (NTRS)

Cohen, Barbara A.

2009-01-01

This slide presentation reviews the United States' contribution to the International Lunar Network (ILN) project, the Anchor Nodes project. The ILN is an initiative of 9 national space agencies to establish a set of robotic geophysical monitoring stations on the surface of the Moon. The project is aimed at furthering the understanding of the lunar composition, and interior structure.

Origin and thermal evolution of Mars

NASA Technical Reports Server (NTRS)

Schubert, G.; Solomon, Sean C.; Turcotte, D. L.; Drake, M. J.; Sleep, N. H.

1993-01-01

The thermal evolution of Mars is governed by subsolidus mantle convection beneath a thick lithosphere. Models of the interior evolution are developed by parameterizing mantle convective heat transport in terms of mantle viscosity, the superadiabatic temperature rise across the mantle and mantle heat production. Geological, geophysical, and geochemical observations of the composition and structure of the interior and of the timing of major events in Martian evolution, such as global differentiation, atmospheric outgassing and the formation of the hemispherical dichotomy and Tharsis, are used to constrain the model computations. Isotope systematics of SNC meteorites suggest core formation essentially contemporaneously with the completion of accretion. Other aspects of this investigation are discussed.

Geophysical Monitoring Station (GEMS)

NASA Astrophysics Data System (ADS)

Banerdt, B.; Dehant, V. M.; Lognonne, P.; Smrekar, S. E.; Spohn, T.; GEMS Mission Team

2011-12-01

GEMS (GEophysical Monitoring Station) is one of three missions undergoing Phase A development for possible selection by NASA's Discovery Program. If selected, GEMS will perform the first comprehensive surface-based geophysical investigation of Mars, filling a longstanding gap in the scientific exploration of the solar system. It will illuminate the fundamental processes of terrestrial planet formation and evolution, providing unique and critical information about the initial accretion of the planet, the formation and differentiation of the core and crust, and the subsequent evolution of the interior. The scientific goals of GEMS are to understand the formation and evolution of terrestrial planets through investigation of the interior structure and processes of Mars and to determine its present level of tectonic activity and impact flux. A straightforward set of scientific objectives address these goals: 1) Determine the size, composition and physical state of the core; 2) Determine the thickness and structure of the crust; 3) Determine the composition and structure of the mantle; 4) Determine the thermal state of the interior; 5) Measure the rate and distribution of internal seismic activity; and 6) Measure the rate of impacts on the surface. To accomplish these objectives, GEMS carries a tightly-focused payload consisting of 3 investigations: 1) SEIS, a 6-component, very-broad-band seismometer, with careful thermal compensation/control and a sensitivity comparable to the best terrestrial instruments across a frequency range of 1 mHz to 50 Hz; 2) HP3 (Heat Flow and Physical Properties Package), an instrumented self-penetrating mole system that trails a string of temperature sensors to measure the thermal gradient and conductivity of the upper several meters, and thus the planetary heat flux; and 3) RISE (Rotation and Interior Structure Experiment), which would use the spacecraft X-band communication system to provide precision tracking for planetary dynamical studies. The two instruments are moved from the lander deck to the martian surface by an Instrument Deployment Arm, with an appropriate location identified using an Instrument Deployment Camera. In order to ensure low risk within the tight Discovery cost limits, GEMS reuses the successful Lockheed Martin Phoenix spacecraft design, with a cruise and EDL system that has demonstrated capability for safe landing on Mars with well-understood costs. To take full advantage of this approach, all science requirements (such as instrument mass and power, landing site, and downlinked data volume) strictly conform to existing, demonstrated capabilities of the spacecraft and mission system. It is widely believed that multiple landers making simultaneous measurements (a network) are required to address the objectives for understanding terrestrial planet interiors. Nonetheless, comprehensive measurements from a single geophysical station are extremely valuable, because observations constraining the structure and processes of the deep interior of Mars are virtually nonexistent. GEMS would utilize sophisticated analysis techniques specific to single-station measurements to determine crustal thickness, mantle structure, core state and size, and heat flow, providing our first real look deep beneath the surface of Mars.

Computing interior eigenvalues of nonsymmetric matrices: application to three-dimensional metamaterial composites.

PubMed

Terao, Takamichi

2010-08-01

We propose a numerical method to calculate interior eigenvalues and corresponding eigenvectors for nonsymmetric matrices. Based on the subspace projection technique onto expanded Ritz subspace, it becomes possible to obtain eigenvalues and eigenvectors with sufficiently high precision. This method overcomes the difficulties of the traditional nonsymmetric Lanczos algorithm, and improves the accuracy of the obtained interior eigenvalues and eigenvectors. Using this algorithm, we investigate three-dimensional metamaterial composites consisting of positive and negative refractive index materials, and it is demonstrated that the finite-difference frequency-domain algorithm is applicable to analyze these metamaterial composites.

Container and method for absorbing and reducing hydrogen concentration

DOEpatents

Wicks, George G.; Lee, Myung W.; Heung, Leung K.

2001-01-01

A method for absorbing hydrogen from an enclosed environment comprising providing a vessel; providing a hydrogen storage composition in communication with a vessel, the hydrogen storage composition further comprising a matrix defining a pore size which permits the passage of hydrogen gas while blocking the passage of gaseous poisons; placing a material within the vessel, the material evolving hydrogen gas; sealing the vessel; and absorbing the hydrogen gas released into the vessel by the hydrogen storage composition. A container for absorbing evolved hydrogen gas comprising: a vessel having an interior and adapted for receiving materials which release hydrogen gas; a hydrogen absorbing composition in communication with the interior, the composition defining a matrix surrounding a hydrogen absorber, the matrix permitting the passage of hydrogen gas while excluding gaseous poisons; wherein, when the vessel is sealed, hydrogen gas, which is released into the vessel interior, is absorbed by the hydrogen absorbing composition.

ATLAS-SOHO: Satellite Arrival and Uncrating, Uncrating of the Propulsion Unit and Electric Module

NASA Technical Reports Server (NTRS)

1995-01-01

The SOHO satellite, part of the International Solar-Terrestrial Physics Program (ISTP), is a solar observatory designed to study the structure, chemical composition, and dynamics of the solar interior. It will also observe the structure (density, temperature and velocity fields), dynamics and composition of the outer solar atmosphere, and the solar wind and its relation to the solar atmosphere. The spacecraft was launched on December 2, 1995. This video shows the unloading of the satellite from the transport plane at the Kennedy Space Station and the lowering to an awaiting flatbed truck. The video also shows the uncrating of the satellite, the propulsion unit and the electric module in a clean room.

Electrical Investigation of Metal-Olivine Systems and Application to the Deep Interior of Mercury

NASA Astrophysics Data System (ADS)

Zhang, Zhou; Pommier, Anne

2017-12-01

We report electrical conductivity measurements on metal-olivine systems at about 5 and 6 GPa and up to 1,675°C in order to investigate the electrical properties of core-mantle boundary (CMB) systems. Electrical experiments were conducted in the multianvil apparatus using the impedance spectroscopy technique. The samples are composed of one metal layer (Fe, FeS, FeSi2, or Fe-Ni-S-Si) and one polycrystalline olivine layer, with the metal:olivine ratio ranging from 1:0.7 to 1:9.2. For all samples, we observe that the bulk electrical conductivity increases with temperature from 10-2.5 to 101.8 S/m, which is higher than the conductivity of polycrystalline olivine but lower than the conductivity of the pure metal phase at similar conditions. In some experiments, a conductivity jump is observed at the temperature corresponding to the melting temperature of the metallic phase. Both the metal:olivine ratio and the metal phase geometry control the electrical conductivity of the two-layer samples. By combining electrical results, textural analyses of the samples, and previous studies of the structure and composition of Mercury's interior, we propose an electrical profile of the deep interior of the planet that accounts for a layered CMB-outer core structure. The electrical model agrees with existing conductivity estimates of Mercury's lower mantle and CMB using magnetic observations and thermodynamic calculations, and thus, supports the hypothesis of a layered CMB-outermost core structure in the present-day interior of Mercury. We propose that the layered CMB-outer core structure is possibly electrically insulating, which may influence the planet's structure and cooling history.

Questionable inheritance: What Processes on Planetesimals Mean for the Bulk Composition of the Earth

NASA Astrophysics Data System (ADS)

Elkins-Tanton, L. T.

2015-12-01

Interrogating Earth's interior is limited to indirect means, such as seismic or magnetic fields, and relies heavily on modeling. A large body of literature either attempts to constrain the composition of the deep mantle by mass balancing the Earth with a chondritic composition, or to demonstrate that the Earth does not have a chondritic composition. These models provide predictions for the composition and density of the ultra-low shear wave provinces and for the D" layer, among others, and compare their results to structures resulting from seismic studies. The bulk composition of the Earth, however, remains an open question. We now know that the planets accreted from embryos that were already differentiated. The complexity of processes that occurred on planetesimals and planetary embryos are just beginning to come to light. Heating by radiogenic 26Al likely produced waves of hydration and dehydration in planetesimals. These free fluids may have carried a wide range of volatiles, moving them from the interior to the lid, or even losing them to space. Simultaneously, the first free fluids may have reacted with metals, producing oxides or sulfides. Further heating is required to reduce these to metals and made core formation possible; or perhaps the earliest cores are not fully metallic. These planetesimals and the embryos they were growing into were subjected to a series of impacts. As the work of Asphaug and his group have demonstrated, some of these are accretionary impacts, and some are hit-and-run, or destructive impacts. These destructive impacts may have reduced the thickness of Mercury's mantle, and stripped the mantle off the metal asteroid Psyche. Where, then would the shattered silicates from such collisions go? Asphuag suggests that at least in part they are added to the growing terrestrial planets. If the planetesimals and planetary embryos were compositionally heterogeneous because of interior fluid and magma movement, then the silicates blown off them by impacts would not have a bulk chondritic composition. The growing planets would not then have a bulk chondritic composition. This talk will discuss the possible ramifications of this model and its application to bulk Earth models.

Validation of an interior noise prediction model for a composite cylinder

NASA Technical Reports Server (NTRS)

Beyer, Todd B.; Grosveld, Ferdinand W.

1987-01-01

An acoustic modal analysis has been performed in the cavity of a composite cylinder model of an aircraft fuselage. The filament wound, composite shell is 12 feet long and 5.5 feet in diameter. A one-half-in. thick plywood floor is attached to the shell 69 deg from the vertical centerline through the bottom of the shell. The acoustic modal frequencies were obtained from a sound pressure level and phase survey conducted throughout the interior volume bounded by the floor, endcaps and stiffened shell, while being excited by white noise from a loudspeaker source. The measured acoustic resonance frequencies and mode shapes compare well with analytical predictions from the Propeller Aircraft Interior Noise (PAIN) model. Details of the theory and derivation of the acoustic characteristics have been included. Reverberation time measurements, using the integrated impulse technique, have been performed to determine acoustic loss factors. These measured loss factors have been input to the PAIN program in order to more accurately predict the space-averaged interior noise of the composite cylinder.

Facile preparation of raisin-bread sandwich-structured magnetic graphene/mesoporous silica composites with C18-modified pore-walls for efficient enrichment of phthalates in environmental water.

PubMed

Huang, Danni; Wang, Xianying; Deng, Chunhui; Song, Guoxin; Cheng, Hefa; Zhang, Xiangmin

2014-01-17

In this study, novel raisin-bread sandwich-structured magnetic graphene/mesoporous silica composites with C18-modified interior pore-walls (mag-graphene@mSiO2-C18) were synthesized by coating mesoporous silica layers onto each side of magnetic graphene through a surfactant-mediated co-condensation sol-gel process. The prepared functionalized nanocomposites possessed marvelous properties of extended plate-like morphology, fine water dispersibility, high magnetic response, large surface area (315.4cm(2)g(-1)), uniform pore size (3.3nm) and C18-modified interior pore-walls. Several kinds of phthalates were selected as model analytes to systematically evaluate the performance of adsorbents in extracting hydrophobic molecules followed by gas chromatography-mass spectrometry analyses. Various extraction parameters, including pH value of sample solution, amounts of adsorbents, adsorption time, species and volume of eluting solvent, and desorption time were optimized. The anti-interference ability to macromolecular proteins was also investigated. Method validations such as linearity, recovery, reproducibility, and limit of detection were also studied. Finally, mag-graphene@mSiO2-C18 composites were successfully applied to analyzing phthalates in environmental water samples. The results indicated that this novel approach offered an attractive alternative for rapid, convenient, efficient and selective magnetic solid-phase extraction for targeted hydrophobic compounds. Copyright © 2013 Elsevier B.V. All rights reserved.

Mixed-conifer forests of central Oregon: Effects of logging and fire exclusion vary with environment

Treesearch

Andrew G. Merschel; Thomas A. Spies; Emily K. Heyerdahl

2014-01-01

Twentieth-century land management has altered the structure and composition of mixed-conifer forests and decreased their resilience to fire, drought, and insects in many parts of the Interior West. These forests occur across a wide range of environmental settings and historical disturbance regimes, so their response to land management is likely to vary across...

Acceleration of vegetation turnover and element cycling by mammalian herbivory in riparian ecosystems

Treesearch

Lem G. Butler; Knut Kielland

2008-01-01

1. We examined the effects of browsing by moose and snowshoe hares on vegetation structure, species composition, plant demography and element cycling in 25 riparian (willow) vegetation stands along the Tanana River, interior Alaska, across a 250-km gradient that represented a fivefold range in moose densities (0.2 to 1.0 km-2). 2. Browsing...

Exploring the Alaskan black spruce ecosystem: variability in species composition, ecosystem function, and fire history

Treesearch

T.N. Hollingsworth

2008-01-01

In this overview, I present extensive studies looking at the structure and function of the black spruce (Picea mariana) ecosystem of the boreal region of interior Alaska. One of the studies provides a classification of black spruce communities, the most abundant forest type in the region. Other studies examine large-scale processes that drive this...

Chapter 15 - Composition and structure of whitebark and limber pine stands in the Interior West and the silvicultural implications (Project INT-EM-B-14-01)

Treesearch

James N. Long; John Shaw; Marcella Windmuller-Campione

2018-01-01

As forest communities continue to experience interactions between climate change and shifting disturbance regimes, there is anincreased need to link ecological understanding to applied management. Whitebark pine (Pinus albicaulis) and limber pine (P. flexilis) are important high-elevation five-needle pines in the...

The compression behavior of blödite at low and high temperature up to ~10GPa: Implications for the stability of hydrous sulfates on icy planetary bodies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Comodi, Paola; Stagno, Vincenzo; Zucchini, Azzurra

Recent satellite inferences of hydrous sulfates as recurrent minerals on the surface of icy planetary bodies link with the potential mineral composition of their interior. Blödite, a mixed Mg-Na sulfate, is here taken as representative mineral of icy satellites surface to investigate its crystal structure and stability at conditions of the interior of icy bodies. To this aim we performed in situ synchrotron angle-dispersive X-ray powder diffraction experiments on natural blödite at pressures up to ~10.4 GPa and temperatures from ~118.8 K to ~490.0 K using diamond anvil cell technique to investigate the compression behavior and establish a low-to-high temperaturemore » equation of state that can be used as reference when modeling the interior of sulfate-rich icy satellites such as Ganymede.« less

Electrical conductivity structure of the mantle derived from inversion of geomagnetic observatory data: implications for lateral variations in temperature, composition and water content.

NASA Astrophysics Data System (ADS)

Munch, Federico; Grayver, Alexander; Khan, Amir; Kuvshinov, Alexey

2017-04-01

As most of Earth's interior remains geochemically unsampled, geophysical techniques based on seismology, geodesy, gravimetry, and electromagnetic studies play prominent roles because of their ability to sense structure at depth. Although seismic tomography maps show a variety of structures, separating thermal and compositional contributions from seismic velocities alone still remains a challenging task. Alternatively, as electrical conductivity is sensitive to temperature, chemical composition, oxygen fugacity, water content, and the presence of melt, it can serve for determining chemistry, mineralogy, and physical structure of the deep mantle. In this work we estimate and invert local C-responses (period range 3-100 days) for a number of worldwide geomagnetic observatories to map lateral variations of electrical conductivity in Earth's mantle (400-1600 km depth). The obtained conductivity profiles are interpreted in terms of basalt fraction in a basalt-harzburgite mixture, temperature structure, and water content variations. Interpretation is based on a self-consistent thermodynamic calculation of mineral phase equilibria, electrical conductivity databases, and probabilistic inverse methods.

Density is not Destiny: Characterizing Terrestrial Exoplanet Geology from Stellar Compositional Abundances

NASA Astrophysics Data System (ADS)

Unterborn, Cayman T.

2018-01-01

A planet’s mass-radius relationship alone is not a good indicator for its potential to be "Earth-like." While useful in coarse characterizations for distinguishing whether an exoplanet is water/atmosphere- or rock/iron-dominated, there is considerable degeneracy in using the mass-radius relation to determine the mineralogy and structure of a purely terrestrial planet like the Earth. The chemical link between host-stars and rocky planets and the utility of this connection in breaking the degeneracy in the mass-radius relationship is well documented. Given the breadth of observed stellar compositions, modeling the complex effects of these compositional variations on a terrestrial planet’s mineralogy, structure and temperature profile, and the potential pitfalls therein, falls within the purview of the geosciences.I will demonstrate here, the utility in adopting the composition of a terrestrial planet’s host star for contextualizing individual systems (e.g. TRAPPIST-1), as well as for the more general case of quantifying the geophysical consequences of stellar compositional diversity. This includes the potential for a host-star to produce planets able to undergo mantle convection, surface-to-interior degassing and long-term plate tectonics. As we search for truly “Earth-like” planets, we must move away from the simple density-driven definition of “Earth-like” and towards a more holistic view that includes both geochemistry and geophysics. Combining geophysical models and those of planetary formation with host-star abundance data, then, is of paramount importance. This will aid not only in our understanding of the mass-radius relationship but also provide foundational results necessary interpreting future atmospheric observations through the lens of surface-interior interactions (e.g. volcanism) and planetary evolution as a whole.

Planetary Magnetism

NASA Technical Reports Server (NTRS)

Connerney, J. E. P.

2007-01-01

The chapter on Planetary Magnetism by Connerney describes the magnetic fields of the planets, from Mercury to Neptune, including the large satellites (Moon, Ganymede) that have or once had active dynamos. The chapter describes the spacecraft missions and observations that, along with select remote observations, form the basis of our knowledge of planetary magnetic fields. Connerney describes the methods of analysis used to characterize planetary magnetic fields, and the models used to represent the main field (due to dynamo action in the planet's interior) and/or remnant magnetic fields locked in the planet's crust, where appropriate. These observations provide valuable insights into dynamo generation of magnetic fields, the structure and composition of planetary interiors, and the evolution of planets.

NICER Packaging for SpaceX CRS-11

NASA Image and Video Library

2017-04-06

Inside the Space Station Processing Facility high bay at NASA's Kennedy Space Center in Florida, technicians prepare the Neutron star Interior Composition Explorer, or NICER, payload for final packaging. NICER will be delivered to the International Space Station aboard the SpaceX Dragon cargo carrier on the company’s 11th commercial resupply services mission to the space station. NICER will study neutron stars through soft X-ray timing. NICER will enable rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft X-ray band with unprecedented sensitivity, probing interior structure, the origins of dynamic phenomena and the mechanisms that underlie the most powerful cosmic particle accelerators known.

NICER Packaging for SpaceX CRS-11

NASA Image and Video Library

2017-04-06

Inside the Space Station Processing Facility high bay at NASA's Kennedy Space Center in Florida, the Neutron star Interior Composition Explorer, or NICER, payload is secured on a special test stand. NICER will be delivered to the International Space Station aboard the SpaceX Dragon cargo carrier on the company’s 11th commercial resupply services mission to the space station. NICER will study neutron stars through soft X-ray timing. NICER will enable rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft X-ray band with unprecedented sensitivity, probing interior structure, the origins of dynamic phenomena and the mechanisms that underlie the most powerful cosmic particle accelerators known.

NICER Packaging for SpaceX CRS-11

NASA Image and Video Library

2017-04-06

Inside the Space Station Processing Facility high bay at NASA's Kennedy Space Center in Florida, a technician prepares the Neutron star Interior Composition Explorer, or NICER, payload for final packaging. NICER will be delivered to the International Space Station aboard the SpaceX Dragon cargo carrier on the company’s 11th commercial resupply services mission to the space station. NICER will study neutron stars through soft X-ray timing. NICER will enable rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft X-ray band with unprecedented sensitivity, probing interior structure, the origins of dynamic phenomena and the mechanisms that underlie the most powerful cosmic particle accelerators known.

NICER Packaging for SpaceX CRS-11

NASA Image and Video Library

2017-04-06

Inside the Space Station Processing Facility high bay at NASA's Kennedy Space Center in Florida, the Neutron star Interior Composition Explorer, or NICER, payload is being prepared for final packaging. NICER will be delivered to the International Space Station aboard the SpaceX Dragon cargo carrier on the company’s 11th commercial resupply services mission to the space station. NICER will study neutron stars through soft X-ray timing. NICER will enable rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft X-ray band with unprecedented sensitivity, probing interior structure, the origins of dynamic phenomena and the mechanisms that underlie the most powerful cosmic particle accelerators known.

The New Jupiter: Results from the Juno Mission

NASA Astrophysics Data System (ADS)

Bolton, Scott

2018-01-01

NASA's Juno mission to Jupiter launched in 2011 and arrived at Jupiter on July 4, 2016. Juno's scientific objectives include the study of Jupiter's interior, atmosphere and magnetosphere with the goal of understanding Jupiter's origin, formation and evolution. An extensive campaign of Earth based observations of Jupiter and the solar wind were orchestrated to complement Juno measurements during Juno's approach to Jupiter and during its orbital mission around Jupiter. This presentation provides an overview of results from the Juno measurements during the early phases of Juno's prime mission. Scientific results include Jupiter's interior structure, magnetic field, deep atmospheric dynamics and composition, and the first in-situ exploration of Jupiter's polar magnetosphere and aurorae.

NICER Transfer (for SpaceX CRS-11)

NASA Image and Video Library

2017-04-12

Inside the Space Station Processing Facility high bay at NASA's Kennedy Space Center in Florida, the Neutron star Interior Composition Explorer, or NICER, payload is secured inside a protective container. NICER will be delivered to the International Space Station aboard the SpaceX Dragon cargo carrier on the company’s 11th commercial resupply services mission to the space station. NICER will study neutron stars through soft X-ray timing. NICER will enable rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft X-ray band with unprecedented sensitivity, probing interior structure, the origins of dynamic phenomena and the mechanisms that underlie the most powerful cosmic particle accelerators known.

Distribution of millipedes (Myriapoda, Diplopoda) along a forest interior - forest edge - grassland habitat complex.

PubMed

Bogyó, Dávid; Magura, Tibor; Nagy, Dávid D; Tóthmérész, Béla

2015-01-01

We studied the distribution of millipedes in a forest interior-forest edge-grassland habitat complex in the Hajdúság Landscape Protection Area (NE Hungary). The habitat types were as follows: (1) lowland oak forest, (2) forest edge with increased ground vegetation and shrub cover, and (3) mesophilous grassland. We collected millipedes by litter and soil sifting. There were overall 30 sifted litter and soil samples: 3 habitat types × 2 replicates × 5 soil and litter samples per habitats. We collected 9 millipede species; the most abundant species was Glomeristetrasticha, which was the most abundant species in the forest edge as well. The most abundant species in the forest interior was Kryphioiulusoccultus, while the most abundant species in the grassland was Megaphyllumunilineatum. Our result showed that the number of millipede species was significantly lower in the grassland than in the forest or in the edge, however there were no significant difference in the number of species between the forest interior and the forest edge. We found significantly the highest number of millipede individuals in the forest edge. There were differences in the composition of the millipede assemblages of the three habitats. The results of the DCCA showed that forest edge and forest interior habitats were clearly separated from the grassland habitats. The forest edge habitat was characterized by high air temperature, high soil moisture, high soil pH, high soil enzyme activity, high shrub cover and low canopy cover. The IndVal and the DCCA methods revealed the following character species of the forest edge habitats: Glomeristetrasticha and Leptoiuluscibdellus. Changes in millipede abundance and composition were highly correlated with the vegetation structure.

Lightweight composites for modular panelized construction

NASA Astrophysics Data System (ADS)

Vaidya, Amol S.

Rapid advances in construction materials technology have enabled civil engineers to achieve impressive gains in the safety, economy, and functionality of structures built to serve the common needs of society. Modular building systems is a fast-growing modern, form of construction gaining recognition for its increased efficiency and ability to apply modern technology to the needs of the market place. In the modular construction technique, a single structural panel can perform a number of functions such as providing thermal insulation, vibration damping, and structural strength. These multifunctional panels can be prefabricated in a manufacturing facility and then transferred to the construction site. A system that uses prefabricated panels for construction is called a "panelized construction system". This study focuses on the development of pre-cast, lightweight, multifunctional sandwich composite panels to be used for panelized construction. Two thermoplastic composite panels are proposed in this study, namely Composite Structural Insulated Panels (CSIPs) for exterior walls, floors and roofs, and Open Core Sandwich composite for multifunctional interior walls of a structure. Special manufacturing techniques are developed for manufacturing these panels. The structural behavior of these panels is analyzed based on various building design codes. Detailed descriptions of the design, cost analysis, manufacturing, finite element modeling and structural testing of these proposed panels are included in this study in the of form five peer-reviewed journal articles. The structural testing of the proposed panels involved in this study included flexural testing, axial compression testing, and low and high velocity impact testing. Based on the current study, the proposed CSIP wall and floor panels were found satisfactory, based on building design codes ASCE-7-05 and ACI-318-05. Joining techniques are proposed in this study for connecting the precast panels on the construction site. Keywords: Modular panelized construction, sandwich composites, composite structural insulated panels (CSIPs).

Interior and Ejecta Morphologies of Impact Craters on Ganymede

NASA Astrophysics Data System (ADS)

Barlow, Nadine G.; Klaybor, K.; Katz-Wigmore, J.

2006-09-01

We are utilizing Galileo SSI imagery of Ganymede to classify impact crater interior and ejecta morphologies. Although we are in the early stages of compiling our Catalog of Impact Craters on Ganymede, some interesting trends are beginning to emerge. Few craters display obvious ejecta morphologies, but 68 craters are classified as single layer ejecta and 3 as double layer ejecta. We see no obvious correlation of layered ejecta morphologies with terrain or latitude. All layered ejecta craters have diameters between 10 and 40 km. Sinuosity ("lobateness") and ejecta extent ("ejecta mobility ratio") of Ganymede layered ejecta craters are lower than for martian layered ejecta craters. This suggests less mobility of ejecta materials on Ganymede, perhaps due to the colder temperatures. Interior structures being investigated include central domes, peaks, and pits. 57 dome craters, 212 central peak craters, and 313 central pit craters have been identified. Central domes occur in 50-100 km diameter craters while peaks are found in craters between 20 and 50 km and central pit craters range between 29 and 74 km in diameter. The Galileo Regio region displays higher concentrations of central dome and central pit craters than other regions we have investigated. 67% of central pit craters studied to date are small pits, where the ratio of pit diameter to crater diameter is <0.2. Craters containing the three interior structures preferentially occur on darker terrain units, suggesting that an ice-silicate composition is more conducive to interior feature formation than pure ice alone. Results of this study have important implications not only for the formation of specific interior and ejecta morphologies on Ganymede but also for analogous features associated with Martian impact craters. This research is funded through NASA Outer Planets Research Program Award #NNG05G116G to N. G. Barlow.

Superconductive wire

DOEpatents

Korzekwa, David A.; Bingert, John F.; Peterson, Dean E.; Sheinberg, Haskell

1995-01-01

A superconductive article is made by inserting a rigid mandrel into an internal cavity of a first metallic tube, said tube having an interior surface and an exterior surface, said interior surface defining the interior cavity, forming a layer of a superconductive material or superconductive precursor upon the exterior surface of said first metallic tube, machining the layer of superconductive material or superconductive precursor to a predetermined diameter to form an intermediate article configured for insertion into a second metallic tube having an interior diameter corresponding to the predetermined diameter, inserting the machined intermediate article into a second metallic tube having an internal diameter corresponding to the predetermined diameter of the intermediate article to form a composite intermediate article, reducing or ironing the composite intermediate article to a predetermined cross-sectional diameter, and sintering the reduced or ironed composite intermediate article at temperatures and for time sufficient for the superconductive material or superconductive precursor to exhibit superconductivity.

Superconductive wire

DOEpatents

Korzekwa, D.A.; Bingert, J.F.; Peterson, D.E.; Sheinberg, H.

1995-07-18

A superconductive article is made by inserting a rigid mandrel into an internal cavity of a first metallic tube, said tube having an interior surface and an exterior surface, said interior surface defining the interior cavity, forming a layer of a superconductive material or superconductive precursor upon the exterior surface of said first metallic tube, machining the layer of superconductive material or superconductive precursor to a predetermined diameter to form an intermediate article configured for insertion into a second metallic tube having an interior diameter corresponding to the predetermined diameter, inserting the machined intermediate article into a second metallic tube having an internal diameter corresponding to the predetermined diameter of the intermediate article to form a composite intermediate article, reducing or ironing the composite intermediate article to a predetermined cross-sectional diameter, and sintering the reduced or ironed composite intermediate article at temperatures and for time sufficient for the superconductive material or superconductive precursor to exhibit superconductivity. 2 figs.

The influence of habitat structure on bird species composition in lowland malaysian rain forests.

PubMed

Mansor, Mohammad Saiful; Sah, Shahrul Anuar Mohd

2012-05-01

Bird surveys were conducted in the Bukit Kepala Gajah limestone area in Lenggong, Perak from July 2010 to January 2011. The study area was divided into three zones: forest edge, forest intermediate and forest interior. A point-count distance sampling method was used in the bird surveys. The study recorded 7789 detections, representing 100 bird species belonging to 28 families. Pycnonotidae, Timaliidae and Nectariniidae were the dominant families overall and showed the highest number of observations recorded in the study area whereas Motacillidae showed the fewest observations. The bird species were grouped into three feeding guilds: insectivores, frugivores and others (omnivores, carnivores, nectarivores and granivores). The species richness of insectivorous birds differed significantly among the forest zones sampled (Kruskal-Wallis: α=0.05, H=10.979, d.f.=2, p=0.004), with more insectivorous birds occurring in the forest interior. No significant differences were found among the zones in the species richness of either the frugivore guild or the composite others guild.

The Influence of Habitat Structure on Bird Species Composition in Lowland Malaysian Rain Forests

PubMed Central

Mansor, Mohammad Saiful; Sah, Shahrul Anuar Mohd

2012-01-01

Bird surveys were conducted in the Bukit Kepala Gajah limestone area in Lenggong, Perak from July 2010 to January 2011. The study area was divided into three zones: forest edge, forest intermediate and forest interior. A point-count distance sampling method was used in the bird surveys. The study recorded 7789 detections, representing 100 bird species belonging to 28 families. Pycnonotidae, Timaliidae and Nectariniidae were the dominant families overall and showed the highest number of observations recorded in the study area whereas Motacillidae showed the fewest observations. The bird species were grouped into three feeding guilds: insectivores, frugivores and others (omnivores, carnivores, nectarivores and granivores). The species richness of insectivorous birds differed significantly among the forest zones sampled (Kruskal-Wallis: α=0.05, H=10.979, d.f.=2, p=0.004), with more insectivorous birds occurring in the forest interior. No significant differences were found among the zones in the species richness of either the frugivore guild or the composite others guild. PMID:24575221

Composite pipe to metal joint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leslie, James C.; Leslie, II, James C.; Heard, James

A method for making a metal to composite tube joint including selecting an elongated interior fitting constructed with an exterior barrel, reduced in exterior diameter to form a distally facing annular shoulder and then projecting still further distally to form an interior sleeve having a radially outwardly facing bonding surface. Selecting an elongated metal outer sleeve formed proximally with a collar constructed for receipt over the barrel and increased in interior diameter and projecting distally to form an exterior sleeve having a radially inwardly facing bonding surface cooperating with the first bonding surface to form an annulus receiving an extremitymore » of a composite tube and a bond bonding the extremity of the tube to the bonding surfaces.« less

Natural Fiber Composite Retting, Preform Manufacture and Molding (Project 18988/Agreement 16313)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmons, Kevin L.; Howe, Daniel T.; Laddha, Sachin

2009-12-31

Plant-based natural fibers can be used in place of glass in fiber reinforced automotive composites to reduce weight, cost and provide environmental benefits. Current automotive applications use natural fibers in injection molded thermoplastics for interior, non-structural applications. Compression molded natural fiber reinforced thermosets have the opportunity to extend natural fiber composite applications to structural and semi-structural parts and exterior parts realizing further vehicle weight savings. The development of low cost molding and fiber processing techniques for large volumes of natural fibers has helped in understanding the barriers of non-aqueous retting. The retting process has a significant effect on the fibermore » quality and its processing ability that is related to the natural fiber composite mechanical properties. PNNL has developed a compression molded fiber reinforced composite system of which is the basis for future preforming activities and fiber treatment. We are using this process to develop preforming techniques and to validate fiber treatment methods relative to OEM provided application specifications. It is anticipated for next fiscal year that demonstration of larger quantities of SMC materials and molding of larger, more complex components with a more complete testing regimen in coordination with Tier suppliers under OEM guidance.« less

The intercrater plains of Mercury and the Moon: Their nature, origin and role in terrestrial planet evolution. Remote sensing and physical data and the Moon. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Leake, M. A.

1982-01-01

Imagery data from Mariner 10 and Lunar Orbiter IV form the major base of observations analyzed. But a variety of other information aids in constraining the composition and structure of the Moon and Mercury, and in particular, provides input to the problem of the nature and origin of their intercrater plains. This information for Mercury is remotely sensed from Earth or from the Mariner 10 spacecraft. Lunar data includes, of course, ground truth information from the Apollo landing sites. Since neither intercrater region was sampled, lunar and Mercurian data are similar in type and limitations. Constraints on surface and interior composition and structure are reviewed.

Teaching the Interior Composition and Rheology of the Earth to Undergraduate Students Using an Inquiry Based Approach

NASA Astrophysics Data System (ADS)

Hayden, T. G.; Callahan, C. N.; Sibert, R. J.; Ewald, S. K.

2011-12-01

Most introductory geology courses include a lesson on the internal layered structure of the Earth. Due to the abstract nature of the content, this topic is difficult to teach using an inquiry-based approach. The challenge is two-fold: first, students cannot directly see the layers from their perspective on the earth's surface, and second, students have trouble grasping the vast scale of the earth, which far exceeds their everyday experiences. In addition, the two separate classification systems for dividing the internal structure of the Earth are often a point of confusion and source of misconceptions. In response to this challenge, we developed an inquiry lesson that scaffolds students' understanding of the compositional and rheological properties of the Earth's interior. The intent is to build students' understanding of the Earth's layers by guiding their attention to the reasons for the separate classification systems and the individual layers. The investigation includes teacher- or material-driven components such as guiding questions and specific hand-samples for analogues as well as student-driven components like collecting data and constructing explanations. The lesson opens with a series of questions designed to elicit students' existing ideas about the Earth's interior. The students are then guided to make observations of hand samples meant to represent examples of the crust and mantle as well as physical materials meant to serve as analogues for the lithosphere and asthenosphere. The lesson concludes with students integrating their observations into a model of the Earth's internal structure that accounts for both the compositional and rheological properties. Although this lesson was originally developed as a roughly 60 minute lesson for a class of 24 students, we also note ways this lesson can be modified for use at a variety of course levels. The lesson was pilot-tested in an introductory Earth Science course for future elementary (K-8) teachers. Data collected includes both pre- and post-instruction drawings as well as responses to multiple-choice test items derived from the Geoscience Content Inventory (GCI).

Neutron Star Interior Composition Explorer (NICE)

NASA Technical Reports Server (NTRS)

Gendreau, Keith C.; Arzoumanian, Zaven

2008-01-01

This viewgraph presentation contains an overview of the mission of the Neutron Star Interior Composition Explorer (NICE), a proposed International Space Station (ISS) payload dedicated ot the study of neutron stars. There are also reviews of the Science Objectives of the payload,the science measurements, the design and the expected performance for the instruments for NICE,

Constraining the interior density profile of a Jovian planet from precision gravity field data

NASA Astrophysics Data System (ADS)

Movshovitz, Naor; Fortney, Jonathan J.; Helled, Ravit; Hubbard, William B.; Thorngren, Daniel; Mankovich, Chris; Wahl, Sean; Militzer, Burkhard; Durante, Daniele

2017-10-01

The external gravity field of a planetary body is determined by the distribution of mass in its interior. Therefore, a measurement of the external field, properly interpreted, tells us about the interior density profile, ρ(r), which in turn can be used to constrain the composition in the interior and thereby learn about the formation mechanism of the planet. Planetary gravity fields are usually described by the coefficients in an expansion of the gravitational potential. Recently, high precision measurements of these coefficients for Jupiter and Saturn have been made by the radio science instruments on the Juno and Cassini spacecraft, respectively.The resulting coefficients come with an associated uncertainty. And while the task of matching a given density profile with a given set of gravity coefficients is relatively straightforward, the question of how best to account for the uncertainty is not. In essentially all prior work on matching models to gravity field data, inferences about planetary structure have rested on imperfect knowledge of the H/He equation of state and on the assumption of an adiabatic interior. Here we wish to vastly expand the phase space of such calculations. We present a framework for describing all the possible interior density structures of a Jovian planet, constrained only by a given set of gravity coefficients and their associated uncertainties. Our approach is statistical. We produce a random sample of ρ(a) curves drawn from the underlying (and unknown) probability distribution of all curves, where ρ is the density on an interior level surface with equatorial radius a. Since the resulting set of density curves is a random sample, that is, curves appear with frequency proportional to the likelihood of their being consistent with the measured gravity, we can compute probability distributions for any quantity that is a function of ρ, such as central pressure, oblateness, core mass and radius, etc. Our approach is also bayesian, in that it can utilize any prior assumptions about the planet's interior, as necessary, without being overly constrained by them.We demonstrate this approach with a sample of Jupiter interior models based on recent Juno data and discuss prospects for Saturn.

Constraining Saturn's interior density profile from precision gravity field measurement obtained during Grand Finale

NASA Astrophysics Data System (ADS)

Movshovitz, N.; Fortney, J. J.; Helled, R.; Hubbard, W. B.; Mankovich, C.; Thorngren, D.; Wahl, S. M.; Militzer, B.; Durante, D.

2017-12-01

The external gravity field of a planetary body is determined by the distribution of mass in its interior. Therefore, a measurement of the external field, properlyinterpreted, tells us about the interior density profile, ρ(r), which in turn can be used to constrain the composition in the interior and thereby learn about theformation mechanism of the planet. Recently, very high precision measurements of the gravity coefficients for Saturn have been made by the radio science instrument on the Cassini spacecraft during its Grand Finale orbits. The resulting coefficients come with an associated uncertainty. The task of matching a given density profile to a given set of gravity coefficients is relatively straightforward, but the question of how to best account for the uncertainty is not. In essentially all prior work on matching models to gravity field data inferences about planetary structure have rested on assumptions regarding the imperfectly known H/He equation of state and the assumption of an adiabatic interior. Here we wish to vastly expand the phase space of such calculations. We present a framework for describing all the possible interior density structures of a Jovian planet constrained by a given set of gravity coefficients and their associated uncertainties. Our approach is statistical. We produce a random sample of ρ(a) curves drawn from the underlying (and unknown) probability distribution of all curves, where ρ is the density on an interior level surface with equatorial radius a. Since the resulting set of density curves is a random sample, that is, curves appear with frequency proportional to the likelihood of their being consistent with the measured gravity, we can compute probability distributions for any quantity that is a function of ρ, such as central pressure, oblateness, core mass and radius, etc. Our approach is also Bayesian, in that it can utilize any prior assumptions about the planet's interior, as necessary, without being overly constrained by them. We apply this approach to produce a sample of Saturn interior models based on gravity data from Grand Finale orbits and discuss their implications.

Macrofaunal Patterns in and around du Couedic and Bonney Submarine Canyons, South Australia

PubMed Central

Dittmann, Sabine; Sorokin, Shirley J.; Hendrycks, Ed

2015-01-01

Two South Australian canyons, one shelf-incising (du Couedic) and one slope-limited (Bonney) were compared for macrofaunal patterns on the shelf and slope that spanned three water masses. It was hypothesized that community structure would (H1) significantly differ by water mass, (H2) show significant regional differences and (H3) differ significantly between interior and exterior of each canyon. Five hundred and thirty-one species of macrofauna ≥1 mm were captured at 27 stations situated in depth stratified transects inside and outside the canyons from 100 to1500 m depth. The macrofauna showed a positive relationship to depth in abundance, biomass, species richness and community composition while taxonomic distinctness and evenness remained high at all depths. Biotic variation on the shelf was best defined by variation in bottom water primary production while sediment characteristics and bottom water oxygen, temperature and nutrients defined biotic variation at greater depth. Community structure differed significantly (p<0.01) among the three water masses (shelf-flowing South Australian current, upper slope Flinders current and lower slope Antarctic Intermediate Water) (H1). Although community differences between the du Couedic and Bonney regions were marginally above significance at p = 0.05 (H2), over half of the species captured were unique to each region. This supports the evidence from fish and megafaunal distributions that the du Couedic and Bonney areas are in different bioregions. Overall, the canyon interiors were not significantly different in community composition from the exterior (H3). However, both canyons had higher abundance and/or biomass, increased species dominance, different species composition and coarser sediments near the canyon heads compared to outside the canyons at the same depth (500 m), suggestive of heightened currents within the canyons that influence community composition there. At 1000–1500 m, the canyon interiors were depauperate, typical of V-shaped canyons elsewhere. The large number of species captured, given the relatively low sampling effort and focus on the larger macrofauna, support previous studies that identify the South Australian coast as a high biodiversity area. PMID:26618354

Manipulating the optical properties of symmetrically branched Au/Pd nanocrystals through interior design.

PubMed

DeSantis, Christopher J; Skrabalak, Sara E

2014-05-25

Au/Pd octopods with hollow, cubic interiors and Oh symmetry were synthesized for the first time by etching core@shell Pd@Au/Pd octopods to selectively remove their Pd interiors. Integration of multiple architectural features - in this case branching symmetry, composition, and interior design - into one nanostructure provides design strategies to new plasmonic colloids.

THERMAL EVOLUTION AND STRUCTURE MODELS OF THE TRANSITING SUPER-EARTH GJ 1214b

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nettelmann, N.; Fortney, J. J.; Kramm, U.

The planet GJ 1214b is the second known super-Earth with a measured mass and radius. Orbiting a quiet M star, it receives considerably less mass-loss driving X-ray and UV radiation than CoRoT-7b, so that the interior may be quite dissimilar in composition, including the possibility of a large fraction of water. We model the interior of GJ 1214b assuming a two-layer (envelope+rock core) structure where the envelope material is either H/He, pure water, or a mixture of H/He and H{sub 2}O. Within this framework, we perform models of the thermal evolution and contraction of the planet. We discuss possible compositionsmore » that are consistent with M{sub p} = 6.55 M{sub +}, R{sub p} = 2.678 R{sub +}, an age {tau} = 3-10 Gyr, and the irradiation level of the atmosphere. These conditions require that if water exists in the interior, it must remain in a fluid state, with important consequences for magnetic field generation. These conditions also require the atmosphere to have a deep isothermal region extending down to 80-800 bar, depending on composition. Our results bolster the suggestion of a metal-enriched H/He atmosphere for the planet, as we find water-world models that lack an H/He atmosphere to require an implausibly large water-to-rock ratio of more than 6:1. We instead favor an H/He/H{sub 2}O envelope with high water mass fraction ({approx}0.5-0.85), similar to recent models of the deep envelope of Uranus and Neptune. Even with these high water mass fractions in the H/He envelope, generally the bulk composition of the planet can have subsolar water:rock ratios. Dry, water-enriched, and pure water envelope models differ to an observationally significant level in their tidal Love numbers k{sub 2} of, respectively, {approx}0.018, {approx}0.15, and {approx}0.7.« less

A Real-Time Microwave Camera at K-Band (24 GHz)

NASA Technical Reports Server (NTRS)

Ghasr, M. T.; Abou-Khousa, M.; Baumgartner, M. A.; Zoughi, R.

2009-01-01

Nondestructive testing (NDT) community has been moving towards effective and robust inspection systems that can provide real-time information about materials, geometrical, structural and mechanical characteristics of composite materials/structures. Moreover, in many applications it is desired to have an image of the structure, after which the information contained in the image is correlated to the above characteristics. Microwave signals penetrate inside of dielectric composite structures and their interaction with the interior of the structure renders critical information for NDT purposes. Subsequently, this information (i.e., magnitude and phase or reflected signal) may be used to produce an image of the interior of the structure revealing potential flaws or anomalies. Image processing and reconstruction techniques may also be incorporated to produce high-resolution images (i.e., synthetic-aperture, back-propagation, etc.). There are several different approaches for designing areal-time microwave camera system. One approach is based on modulated scatterer technique (MST), which is used to tag scattered electric field in a discrete two-dimensional (2D) spatial domain (e.g. a retina) resulting in the 2D magnitude and phase distribution of the scattered electric field which is required for producing an image of a material or structure under inspection. The ability to rapidly modulate resonant slot antennas in such a retina along with using receivers with fast responses provide for real-time image production capability. Design issue and criteria become more challenging at higher frequencies and for a relatively large retina size. This paper presents the basic design and challenges for a microwave camera with a retina size of 6" by 6" operating at a frequency of 24 GHz.

The impact of edge effect on termite community (Blattodea: Isoptera) in fragments of Brazilian Atlantic Rainforest.

PubMed

Almeida, C S; Cristaldo, P F; Florencio, D F; Ribeiro, E J M; Cruz, N G; Silva, E A; Costa, D A; Araújo, A P A

2017-01-01

Habitat fragmentation is considered to be one of the biggest threats to tropical ecosystem functioning. In this region, termites perform an important ecological role as decomposers and ecosystem engineers. In the present study, we tested whether termite community is negatively affected by edge effects on three fragments of Brazilian Atlantic Rainforest. Termite abundance and vegetation structure were sampled in 10 transects (15 × 2 m), while termite richness, activity, and soil litter biomass were measured in 16 quadrants (5 × 2 m) at forest edge and interior of each fragment. Habitat structure (i.e. number of tree, diameter at breast height and soil litter biomass) did not differ between forest edge and interior of fragments. Termite richness, abundance and activity were not affected by edge effect. However, differences were observed in the β diversity between forest edge and interior as well as in the fragments sampled. The β diversity partitioning indicates that species turnover is the determinant process of termite community composition under edge effect. Our results suggest that conservation strategies should be based on the selection of several distinct sites instead of few rich sites (e.g. nesting).

Inert electrode containing metal oxides, copper and noble metal

DOEpatents

Ray, Siba P.; Woods, Robert W.; Dawless, Robert K.; Hosler, Robert B.

2001-01-01

A cermet composite material is made by treating at an elevated temperature a mixture comprising a compound of iron and a compound of at least one other metal, together with an alloy or mixture of copper and a noble metal. The alloy or mixture preferably comprises particles having an interior portion containing more copper than noble metal and an exterior portion containing more noble metal than copper. The noble metal is preferably silver. The cermet composite material preferably includes alloy phase portions and a ceramic phase portion. At least part of the ceramic phase portion preferably has a spinel structure.

Inert electrode containing metal oxides, copper and noble metal

DOEpatents

Ray, Siba P.; Woods, Robert W.; Dawless, Robert K.; Hosler, Robert B.

2000-01-01

A cermet composite material is made by treating at an elevated temperature a mixture comprising a compound of iron and a compound of at least one other metal, together with an alloy or mixture of copper and a noble metal. The alloy or mixture preferably comprises particles having an interior portion containing more copper than noble metal and an exterior portion containing more noble metal than copper. The noble metal is preferably silver. The cermet composite material preferably includes alloy phase portions and a ceramic phase portion. At least part of the ceramic phase portion preferably has a spinel structure.

Vibrations and structureborne noise in space station

NASA Technical Reports Server (NTRS)

Vaicaitis, R.

1985-01-01

Theoretical models were developed capable of predicting structural response and noise transmission to random point mechanical loads. Fiber reinforced composite and aluminum materials were considered. Cylindrical shells and circular plates were taken as typical representatives of structural components for space station habitability modules. Analytical formulations include double wall and single wall constructions. Pressurized and unpressurized models were considered. Parametric studies were conducted to determine the effect on structural response and noise transmission due to fiber orientation, point load location, damping in the core and the main load carrying structure, pressurization, interior acoustic absorption, etc. These analytical models could serve as preliminary tools for assessing noise related problems, for space station applications.

Method of making a composite tube to metal joint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leslie, James C.; Leslie, II, James C.; Heard, James

A method for making a metal to composite tube joint including selecting an elongated interior fitting constructed with an exterior barrel, reduced in exterior diameter to form a distally facing annular shoulder and then projecting still further distally to form an interior sleeve having a radially outwardly facing bonding surface. Selecting an elongated metal outer sleeve formed proximally with a collar constructed for receipt over the barrel and increased in interior diameter and projecting distally to form an exterior sleeve having a radially inwardly facing bonding surface cooperating with the first bonding surface to form an annulus receiving an extremitymore » of a composite tube and a bond bonding the extremity of the tube to the bonding surfaces.« less

Residential Interior Design as Complex Composition: A Case Study of a High School Senior's Composing Process

ERIC Educational Resources Information Center

Smagorinsky, Peter; Zoss, Michelle; Reed, Patty M.

2006-01-01

This research analyzed the composing processes of one high school student as she designed the interiors of homes for a course in interior design. Data included field notes, an interview with the teacher, artifacts from the class, and the focal student's concurrent and retrospective protocols in relation to her design of home interiors. The…

NICER Packaging for SpaceX CRS-11

NASA Image and Video Library

2017-04-06

Inside the Space Station Processing Facility high bay at NASA's Kennedy Space Center in Florida, technicians assist as a crane is used to lift the Neutron star Interior Composition Explorer, or NICER, payload up from its carrier. NICER will be delivered to the International Space Station aboard the SpaceX Dragon cargo carrier on the company’s 11th commercial resupply services mission to the space station. NICER will study neutron stars through soft X-ray timing. NICER will enable rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft X-ray band with unprecedented sensitivity, probing interior structure, the origins of dynamic phenomena and the mechanisms that underlie the most powerful cosmic particle accelerators known.

NICER Transfer (for SpaceX CRS-11)

NASA Image and Video Library

2017-04-12

Inside the Space Station Processing Facility high bay at NASA's Kennedy Space Center in Florida, the Neutron star Interior Composition Explorer, or NICER, payload is secured inside a protective container and loaded onto a truck outside the high bay. NICER will be delivered to the International Space Station aboard the SpaceX Dragon cargo carrier on the company’s 11th commercial resupply services mission to the space station. NICER will study neutron stars through soft X-ray timing. NICER will enable rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft X-ray band with unprecedented sensitivity, probing interior structure, the origins of dynamic phenomena and the mechanisms that underlie the most powerful cosmic particle accelerators known.

Toward a mineral physics reference model for the Moon's core.

PubMed

Antonangeli, Daniele; Morard, Guillaume; Schmerr, Nicholas C; Komabayashi, Tetsuya; Krisch, Michael; Fiquet, Guillaume; Fei, Yingwei

2015-03-31

The physical properties of iron (Fe) at high pressure and high temperature are crucial for understanding the chemical composition, evolution, and dynamics of planetary interiors. Indeed, the inner structures of the telluric planets all share a similar layered nature: a central metallic core composed mostly of iron, surrounded by a silicate mantle, and a thin, chemically differentiated crust. To date, most studies of iron have focused on the hexagonal closed packed (hcp, or ε) phase, as ε-Fe is likely stable across the pressure and temperature conditions of Earth's core. However, at the more moderate pressures characteristic of the cores of smaller planetary bodies, such as the Moon, Mercury, or Mars, iron takes on a face-centered cubic (fcc, or γ) structure. Here we present compressional and shear wave sound velocity and density measurements of γ-Fe at high pressures and high temperatures, which are needed to develop accurate seismic models of planetary interiors. Our results indicate that the seismic velocities proposed for the Moon's inner core by a recent reanalysis of Apollo seismic data are well below those of γ-Fe. Our dataset thus provides strong constraints to seismic models of the lunar core and cores of small telluric planets. This allows us to propose a direct compositional and velocity model for the Moon's core.

Modeling of Structural-Acoustic Interaction Using Coupled FE/BE Method and Control of Interior Acoustic Pressure Using Piezoelectric Actuators

NASA Technical Reports Server (NTRS)

Mei, Chuh; Shi, Yacheng

1997-01-01

A coupled finite element (FE) and boundary element (BE) approach is presented to model full coupled structural/acoustic/piezoelectric systems. The dual reciprocity boundary element method is used so that the natural frequencies and mode shapes of the coupled system can be obtained, and to extend this approach to time dependent problems. The boundary element method is applied to interior acoustic domains, and the results are very accurate when compared with limited exact solutions. Structural-acoustic problems are then analyzed with the coupled finite element/boundary element method, where the finite element method models the structural domain and the boundary element method models the acoustic domain. Results for a system consisting of an isotropic panel and a cubic cavity are in good agreement with exact solutions and experiment data. The response of a composite panel backed cavity is then obtained. The results show that the mass and stiffness of piezoelectric layers have to be considered. The coupled finite element and boundary element equations are transformed into modal coordinates, which is more convenient for transient excitation. Several transient problems are solved based on this formulation. Two control designs, a linear quadratic regulator (LQR) and a feedforward controller, are applied to reduce the acoustic pressure inside the cavity based on the equations in modal coordinates. The results indicate that both controllers can reduce the interior acoustic pressure and the plate deflection.

Present-Day Mars' Seismicity Predicted From 3-D Thermal Evolution Models of Interior Dynamics

NASA Astrophysics Data System (ADS)

Plesa, A.-C.; Knapmeyer, M.; Golombek, M. P.; Breuer, D.; Grott, M.; Kawamura, T.; Lognonné, P.; Tosi, N.; Weber, R. C.

2018-03-01

The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport mission, to be launched in 2018, will perform a comprehensive geophysical investigation of Mars in situ. The Seismic Experiment for Interior Structure package aims to detect global and regional seismic events and in turn offer constraints on core size, crustal thickness, and core, mantle, and crustal composition. In this study, we estimate the present-day amount and distribution of seismicity using 3-D numerical thermal evolution models of Mars, taking into account contributions from convective stresses as well as from stresses associated with cooling and planetary contraction. Defining the seismogenic lithosphere by an isotherm and assuming two end-member cases of 573 K and the 1073 K, we determine the seismogenic lithosphere thickness. Assuming a seismic efficiency between 0.025 and 1, this thickness is used to estimate the total annual seismic moment budget, and our models show values between 5.7 × 1016 and 3.9 × 1019 Nm.

Evolution and structure of Mercury's interior from MESSENGER observations

NASA Astrophysics Data System (ADS)

Tosi, Nicola

2015-04-01

During the past four years, the MESSENGER mission (MErcury Surface, Space Environment, GEochemistry and Ranging) has delivered a wealth of information that has been dramatically advancing the understanding of the geological, chemical, and physical state of Mercury. Taking into account the latest constraints on the interior structure, surface composition, volcanic and tectonic history, we employed numerical models to simulate the thermo-chemical evolution of the planet's interior [1]. Typical evolution scenarios that allow the observational constraints to be satisfied consist of an initial phase of mantle heating accompanied by planetary expansion and the production of a substantial amount of partial melt. The evolution subsequent to 2 Ga is characterised by secular cooling that proceeds approximately at a constant rate and implies that contraction should be still ongoing. Most of the models also predict mantle convection to cease after 3-4 Ga, indicating that Mercury may be no longer dynamically active. In addition, the topography, measured by laser altimetry and the gravity field, obtained from radio-tracking, represent fundamental observations that can be interpreted in terms of the chemical and mechanical structure of the interior. The observed geoid-to-topography ratios at intermediate wavelengths are well explained by the isostatic compensation of the topography associated with lateral variations of the crustal thickness, whose mean value can be estimated to be ~35 km, broadly confirming the predictions of the evolution simulations [2]. Finally, we will show that the degree-2 and 4 of the topography and geoid spectra can be explained in terms of the long-wavelength deformation of the lithosphere resulting from deep thermal anomalies caused by the large latitudinal and longitudinal variations in temperature experienced by Mercury's surface. [1] Tosi N., M. Grott, A.-C. Plesa and D. Breuer (2013). Thermo-chemical evolution of Mercury's interior. Journal of Geophysical Research - Planets, 118, 2474-2487. [2] Padovan S., M. Wieczorek, J.-L. Margot, N. Tosi, and S. Solomon (2015). Thickness of the crust of Mercury from geoid-to-topography ratios. Geophysical Research Letters. In press.

Interior phase transformations and mass-radius relationships of silicon-carbon planets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, Hugh F.; Militzer, Burkhard, E-mail: hughfw@gmail.com

2014-09-20

Planets such as 55 Cancri e orbiting stars with a high carbon-to-oxygen ratio may consist primarily of silicon and carbon, with successive layers of carbon, silicon carbide, and iron. The behavior of silicon-carbon materials at the extreme pressures prevalent in planetary interiors, however, has not yet been sufficiently understood. In this work, we use simulations based on density functional theory to determine high-pressure phase transitions in the silicon-carbon system, including the prediction of new stable compounds with Si{sub 2}C and SiC{sub 2} stoichiometry at high pressures. We compute equations of state for these silicon-carbon compounds as a function of pressure,more » and hence derive interior structural models and mass-radius relationships for planets composed of silicon and carbon. Notably, we predict a substantially smaller radius for SiC planets than in previous models, and find that mass radius relationships for SiC planets are indistinguishable from those of silicate planets. We also compute a new equation of state for iron. We rederive interior models for 55 Cancri e and are able to place more stringent restrictions on its composition.« less

The Interiors of Jupiter and Saturn

NASA Astrophysics Data System (ADS)

Helled, Ravit

2018-05-01

Probing the interiors of the giant planets in our Solar System is not an easy task. This requires a set of observations combined with theoretical models that are used to infer the planetary composition and its depth dependence. The masses of Jupiter and Saturn are 318 and 96 Earth masses, respectively, and since a few decades, we know that they mostly consist of hydrogen and helium. It is the mass of heavy elements (all elements heavier than helium) that is not well determined, as well as its distribution within the planets. While the heavy elements are not the dominating materials in Jupiter and Saturn, they are the key for our understanding of their formation and evolution histories. The planetary internal structure is inferred to fit the available observational constraints including the planetary masses, radii, 1-bar temperatures, rotation rates, and gravitational fields. Then, using theoretical equations of states (EOSs) for hydrogen, helium, their mixtures, and heavier elements (typically rocks and/or ices), a structure model is developed. However, there is no unique solution for the planetary structure, and the results depend on the used EOSs and the model assumptions imposed by the modeler. Standard interior models of Jupiter and Saturn include three main regions: (1) the central region (core) that consists of heavy elements, (2) an inner metallic hydrogen envelope that is helium rich, and (3) an outer molecular hydrogen envelope depleted with helium. The distribution of heavy elements can be either homogenous or discontinuous between the two envelopes. Major model assumptions that can affect the derived internal structure include the number of layers, the heat transport mechanism within the planet (and its entropy), the nature of the core (compact vs. diluted), and the location/pressure where the envelopes are divided. Alternative structure models assume a less distinct division between the layers and/or a less non-homogenous distribution of the heavy elements. The fact that the behavior of hydrogen at high pressures and temperatures in not perfectly known, and that helium separates from hydrogen at the deep interior add sources of uncertainties to the interior model. Today, with accurate measurements of the gravitational fields of Jupiter and Saturn from the Juno and Cassini missions, structure models can be further constrained. At the same time, these measurements introduce new challenges and open question for planetary modelers.

Further Constraints and Uncertainties on the Deep Seismic Structure of the Moon

NASA Technical Reports Server (NTRS)

Lin, Pei-Ying Patty; Weber, Renee C.; Garnero, Ed J.; Schmerr, Nicholas C.

2011-01-01

The Apollo Passive Seismic Experiment (APSE) consisted of four 3-component seismometers deployed between 1969 and 1972, that continuously recorded lunar ground motion until late 1977. The APSE data provide a unique opportunity for investigating the interior of a planet other than Earth, generating the most direct constraints on the elastic structure, and hence the thermal and compositional evolution of the Moon. Owing to the lack of far side moonquakes, past seismic models of the lunar interior were unable to constrain the lowermost 500 km of the interior. Recently, array methodologies aimed at detecting deep lunar seismic reflections found evidence for a lunar core, providing an elastic model of the deepest lunar interior consistent with geodetic parameters. Here we study the uncertainties in these models associated with the double array stacking of deep moonquakes for imaging deep reflectors in the Moon. We investigate the dependency of the array stacking results on a suite of parameters, including amplitude normalization assumptions, polarization filters, assumed velocity structure, and seismic phases that interfere with our desired target phases. These efforts are facilitated by the generation of synthetic seismograms at high frequencies (approx. 1Hz), allowing us to directly study the trade-offs between different parameters. We also investigate expected amplitudes of deep reflections relative to direct P and S arrivals, including predictions from arbitrarily oriented focal mechanisms in our synthetics. Results from separate versus combined station stacking help to establish the robustness of stacks. Synthetics for every path geometry of data were processed identically to that done with data. Different experiments were aimed at examining various processing assumptions, such as adding random noise to synthetics and mixing 3 components to some degree. The principal stacked energy peaks put forth in recent work persist, but their amplitude (which maps into reflector impedance contrast) and timing (which maps into reflector depth) depend on factors that are not well constrained -- most notably, the velocity structure of the overlying lunar interior. Thus, while evidence for the lunar core remains strong, the depths of imaged reflectors have associated uncertainties that will require new seismic data and observations to constrain. These results strongly advocate further investigations on the Moon to better resolve the interior (e.g., Selene missions), for the Moon apparently has a rich history of construction and evolution that is inextricably tied to that of Earth.

The development and manufacture of wood composite wind turbine rotors

NASA Technical Reports Server (NTRS)

Zuteck, M. D.

1982-01-01

The physical properties, operational experience, and construction methods of the wood/epoxy composite MOD 0A wind turbine blades are considered. Blades of this type have accumulated over 10,000 hours of successful operation at the Kahuku, Hawaii and Block Island, Rhode Island test sites. That body of experience is summarized and related to the structural concepts and design drivers which motivated the original design and choice of interior layout. Actual manufacturing experience and associated low first unit costs for these blades, as well as projections for high production rates, are presented. Application of these construction techniques to a wide range of other blade sizes is also considered.

Features of nanostructures sputtering

NASA Astrophysics Data System (ADS)

Kapustin, S. N.; Matveev, V. I.; Eseev, M. K.

2017-09-01

The research of ion sputtering of nanoparticles is interesting both from the fundamental point of view - for researching the interior structure of nanoobjects, and the economical one - nanostructures often play the role of functional supplements in composite materials under the radiation pressure. This process should be taken into account while creating objects decorated by nanoclusters during ion implantation. Polyatomic clusters obtained as a result of ion bombing could be used as nanodisperse catalysts or quantum points.

Radar observations of asteroid 216 kleopatra

PubMed

Ostro; Hudson; Nolan; Margot; Scheeres; Campbell; Magri; Giorgini; Yeomans

2000-05-05

Radar observations of the main-belt, M-class asteroid 216 Kleopatra reveal a dumbbell-shaped object with overall dimensions of 217 kilometers by 94 kilometers by 81 kilometers (+/-25%). The asteroid's surface properties are consistent with a regolith having a metallic composition and a porosity comparable to that of lunar soil. Kleopatra's shape is probably the outcome of an exotic sequence of collisional events, and much of its interior may have an unconsolidated rubble-pile structure.

Aluminum-Alloy-Matrix/Alumina-Reinforcement Composites

NASA Technical Reports Server (NTRS)

Kashalikar, Uday; Rozenoyer, Boris

2004-01-01

Isotropic composites of aluminum-alloy matrices reinforced with particulate alumina have been developed as lightweight, high-specific-strength, less-expensive alternatives to nickel-base and ferrous superalloys. These composites feature a specific gravity of about 3.45 grams per cubic centimeter and specific strengths of about 200 MPa/(grams per cubic centimeter). The room-temperature tensile strength is 100 ksi (689 MPa) and stiffness is 30 Msi (206 GPa). At 500 F (260 C), these composites have shown 80 percent retention in strength and 95 percent retention in stiffness. These materials also have excellent fatigue tolerance and tribological properties. They can be fabricated in net (or nearly net) sizes and shapes to make housings, pistons, valves, and ducts in turbomachinery, and to make structural components of such diverse systems as diesel engines, automotive brake systems, and power-generation, mining, and oil-drilling equipment. Separately, incorporation of these metal matrix composites within aluminum gravity castings for localized reinforcement has been demonstrated. A composite part of this type can be fabricated in a pressure infiltration casting process. The process begins with the placement of a mold with alumina particulate preform of net or nearly net size and shape in a crucible in a vacuum furnace. A charge of the alloy is placed in the crucible with the preform. The interior of the furnace is evacuated, then the furnace heaters are turned on to heat the alloy above its liquidus temperature. Next, the interior of the furnace is filled with argon gas at a pressure about 900 psi (approximately equal to 6.2 MPa) to force the molten alloy to infiltrate the preform. Once infiltrated, the entire contents of the crucible can be allowed to cool in place, and the composite part recovered from the mold.

Numerical Estimation of Sound Transmission Loss in Launch Vehicle Payload Fairing

NASA Astrophysics Data System (ADS)

Chandana, Pawan Kumar; Tiwari, Shashi Bhushan; Vukkadala, Kishore Nath

2017-08-01

Coupled acoustic-structural analysis of a typical launch vehicle composite payload faring is carried out, and results are validated with experimental data. Depending on the frequency range of interest, prediction of vibro-acoustic behavior of a structure is usually done using the finite element method, boundary element method or through statistical energy analysis. The present study focuses on low frequency dynamic behavior of a composite payload fairing structure using both coupled and uncoupled vibro-acoustic finite element models up to 710 Hz. A vibro-acoustic model, characterizing the interaction between the fairing structure, air cavity, and satellite, is developed. The external sound pressure levels specified for the payload fairing's acoustic test are considered as external loads for the analysis. Analysis methodology is validated by comparing the interior noise levels with those obtained from full scale Acoustic tests conducted in a reverberation chamber. The present approach has application in the design and optimization of acoustic control mechanisms at lower frequencies.

Detection of bondline delaminations in multilayer structures with lossy components

NASA Technical Reports Server (NTRS)

Madaras, Eric I.; Winfree, William P.; Smith, B. T.; Heyman, Joseph H.

1988-01-01

The detection of bondline delaminations in multilayer structures using ultrasonic reflection techniques is a generic problem in adhesively bonded composite structures such as the Space Shuttles's Solid Rocket Motors (SRM). Standard pulse echo ultrasonic techniques do not perform well for a composite resonator composed of a resonant layer combined with attenuating layers. Excessive ringing in the resonant layer tends to mask internal echoes emanating from the attenuating layers. The SRM is made up of a resonant steel layer backed by layers of adhesive, rubber, liner and fuel, which are ultrasonically attenuating. The structure's response is modeled as a lossy ultrasonic transmission line. The model predicts that the acoustic response of the system is sensitive to delaminations at the interior bondlines in a few narrow frequency bands. These predictions are verified by measurements on a fabricated system. Successful imaging of internal delaminations is sensitive to proper selection of the interrogating frequency. Images of fabricated bondline delaminations are presented based on these studies.

The Neutron Star Interior Composition Explorer (NICER): Design and Development

NASA Technical Reports Server (NTRS)

Gendreau, Keith C.; Arzoumanian, Zaven; Adkins, Phillip W.; Albert, Cheryl L.; Anders, John F.; Aylward, Andrew T.; Baker, Charles L.; Balsamo, Erin R.; Bamford, William A.; Benegalrao, Suyog S.;

The Neutron star Interior Composition Explorer (NICER): design and development

NASA Astrophysics Data System (ADS)

Gendreau, Keith C.; Arzoumanian, Zaven; Adkins, Phillip W.; Albert, Cheryl L.; Anders, John F.; Aylward, Andrew T.; Baker, Charles L.; Balsamo, Erin R.; Bamford, William A.; Benegalrao, Suyog S.; Berry, Daniel L.; Bhalwani, Shiraz; Black, J. Kevin; Blaurock, Carl; Bronke, Ginger M.; Brown, Gary L.; Budinoff, Jason G.; Cantwell, Jeffrey D.; Cazeau, Thoniel; Chen, Philip T.; Clement, Thomas G.; Colangelo, Andrew T.; Coleman, Jerry S.; Coopersmith, Jonathan D.; Dehaven, William E.; Doty, John P.; Egan, Mark D.; Enoto, Teruaki; Fan, Terry W.; Ferro, Deneen M.; Foster, Richard; Galassi, Nicholas M.; Gallo, Luis D.; Green, Chris M.; Grosh, Dave; Ha, Kong Q.; Hasouneh, Monther A.; Heefner, Kristofer B.; Hestnes, Phyllis; Hoge, Lisa J.; Jacobs, Tawanda M.; Jørgensen, John L.; Kaiser, Michael A.; Kellogg, James W.; Kenyon, Steven J.; Koenecke, Richard G.; Kozon, Robert P.; LaMarr, Beverly; Lambertson, Mike D.; Larson, Anne M.; Lentine, Steven; Lewis, Jesse H.; Lilly, Michael G.; Liu, Kuochia Alice; Malonis, Andrew; Manthripragada, Sridhar S.; Markwardt, Craig B.; Matonak, Bryan D.; Mcginnis, Isaac E.; Miller, Roger L.; Mitchell, Alissa L.; Mitchell, Jason W.; Mohammed, Jelila S.; Monroe, Charles A.; Montt de Garcia, Kristina M.; Mulé, Peter D.; Nagao, Louis T.; Ngo, Son N.; Norris, Eric D.; Norwood, Dwight A.; Novotka, Joseph; Okajima, Takashi; Olsen, Lawrence G.; Onyeachu, Chimaobi O.; Orosco, Henry Y.; Peterson, Jacqualine R.; Pevear, Kristina N.; Pham, Karen K.; Pollard, Sue E.; Pope, John S.; Powers, Daniel F.; Powers, Charles E.; Price, Samuel R.; Prigozhin, Gregory Y.; Ramirez, Julian B.; Reid, Winston J.; Remillard, Ronald A.; Rogstad, Eric M.; Rosecrans, Glenn P.; Rowe, John N.; Sager, Jennifer A.; Sanders, Claude A.; Savadkin, Bruce; Saylor, Maxine R.; Schaeffer, Alexander F.; Schweiss, Nancy S.; Semper, Sean R.; Serlemitsos, Peter J.; Shackelford, Larry V.; Soong, Yang; Struebel, Jonathan; Vezie, Michael L.; Villasenor, Joel S.; Winternitz, Luke B.; Wofford, George I.; Wright, Michael R.; Yang, Mike Y.; Yu, Wayne H.

2016-07-01

During 2014 and 2015, NASA's Neutron star Interior Composition Explorer (NICER) mission proceeded success- fully through Phase C, Design and Development. An X-ray (0.2-12 keV) astrophysics payload destined for the International Space Station, NICER is manifested for launch in early 2017 on the Commercial Resupply Services SpaceX-11 flight. Its scientific objectives are to investigate the internal structure, dynamics, and energetics of neutron stars, the densest objects in the universe. During Phase C, flight components including optics, detectors, the optical bench, pointing actuators, electronics, and others were subjected to environmental testing and integrated to form the flight payload. A custom-built facility was used to co-align and integrate the X-ray "con- centrator" optics and silicon-drift detectors. Ground calibration provided robust performance measures of the optical (at NASA's Goddard Space Flight Center) and detector (at the Massachusetts Institute of Technology) subsystems, while comprehensive functional tests prior to payload-level environmental testing met all instrument performance requirements. We describe here the implementation of NICER's major subsystems, summarize their performance and calibration, and outline the component-level testing that was successfully applied.

Space Science in the Twenty-First Century: Imperatives for the Decades 1995 to 2015. Mission to Planet Earth

NASA Technical Reports Server (NTRS)

1988-01-01

A unified program is outlined for studying the Earth, from its deep interior to its fluid envelopes. A system is proposed for measuring devices involving both space-based and in-situ observations that can accommodate simultaneously a large range of scientific needs. The scientific objectices served by this integrated infrastructure are cased into a framework of four grand themes. In summary these are: to determine the composition, structure, dynamics, and evolution of the Earth's crust and deeper interior; to establish and understand the structure, dynamics, and chemistry of the oceans, atmosphere, and cryosphere, and their interaction with the solid Earth; to characterize the history and dynamics of living organisms and their interaction with the environment; and to monitor and understand the interaction of human activities with the natural environment. A focus on these grand themes will help to understand the origin and fate of the planet, and to place it in the context of the solar system.

Tracking composition of microbial communities for simultaneous nitrification and denitrification in polyurethane foam.

PubMed

Chen, Yuan; Wang, Li; Ma, Fang; Yang, Ji-xian; Qiu, Shan

2014-01-01

The process of simultaneous nitrification and denitrification (SND) of immobilized microorganisms in polyurethane form is discussed. The effect of different positions within the polyurethane carrier on microbial community response for the SND process is investigated by a combination of denaturing gradient gel electrophoresis profiles of the 16S rRNA gene V3 region and scanning electron microscopy. Results show that polyurethane, which consists of a unique porous structure, is an ideal platform for biofilm stratification of aerobe, anaerobe and facultative microorganisms in regard to the SND process. The community structure diversity response to different positions was distinct. The distributions of various functional microbes, detected from the surface aerobic stratification to the interior anaerobic stratification of polyurethane, were mainly nitrifying and denitrifying bacteria. Meanwhile aerobic denitrifying bacteria such as Paracoccus sp., Agrobacterium rubi and Ochrobactrum sp. were also adhered to the interior and surface of polyurethane. The SND process occurring on polyurethane foam was carried out by two independent processes: nitrogen removal and aerobic denitrification.

Proceedings of the Seventh International Conference on Mars

NASA Technical Reports Server (NTRS)

2007-01-01

The oral and poster sessions of the SEVENTH INTERNATIONAL CONFERENCE ON MARS included; The Distribution and Context of Water-related Minerals on Mars; Poster Session: Mars Geology; Geology of the Martian Surface: Lithologic Variation, Composition, and Structure; Water Through Mars' Geologic History; Poster Session: Mars Water and the Martian Interior; Volatiles and Interior Evolution; The Martian Climate and Atmosphere: Variations in Time and Space; Poster Session: The Martian Climate and Current Processes; Modern Mars: Weather, Atmospheric Chemistry, Geologic Processes, and Water Cycle; Public Lecture: Mars Reconnaissance Orbiter's New View of the Red Planet; The North and South Polar Layered Deposits, Circumpolar Regions, and Changes with Time; Poster Session: Mars Polar Science, Astrobiology, Future Missions/Instruments, and Other Mars Science; Mars Astrobiology and Upcoming Missions; and Martian Stratigraphy and Sedimentology: Reading the Sedimentary Record.

NICER Transfer (for SpaceX CRS-11)

NASA Image and Video Library

2017-04-12

Inside the Space Station Processing Facility high bay at NASA's Kennedy Space Center in Florida, the Neutron star Interior Composition Explorer, or NICER, payload is secured inside a protective container. A technician uses a Hyster forklift to pick up the container and move it outside of the high bay. NICER will be delivered to the International Space Station aboard the SpaceX Dragon cargo carrier on the company’s 11th commercial resupply services mission to the space station. NICER will study neutron stars through soft X-ray timing. NICER will enable rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft X-ray band with unprecedented sensitivity, probing interior structure, the origins of dynamic phenomena and the mechanisms that underlie the most powerful cosmic particle accelerators known.

Study of thermal stability and degradation of fire resistant candidate polymers for aircraft interiors

NASA Technical Reports Server (NTRS)

Hsu, M. T. S.

1976-01-01

The thermochemistry of bismaleimide resins and phenolphthalein polycarbonate was studied. Both materials are fire-resistant polymers and may be suitable for aircraft interiors. The chemical composition of the polymers has been determined by nuclear magnetic resonance and infrared spectroscopy and by elemental analysis. Thermal properties of these polymers have been characterized by thermogravimetric analyses. Qualitative evaluation of the volatile products formed in pyrolysis under oxidative and non-oxidative conditions has been made using infrared spectrometry. The residues after pyrolysis were analyzed by elemental analysis. The thermal stability of composite panel and thermoplastic materials for aircraft interiors was studied by thermogravimetric analyses.

[Studies on the growth and reproduction of bacterial communities on structural materials of the international space station].

PubMed

Rakova, N M; Svistunova, Iu V; Novikova, N D

2005-01-01

Probability of microbial growth and reproduction on the ISS interior and equipment materials varying in chemical composition was studied with the strains of Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus saprophyticus, Pseudomonas putida etc. sampled from the ISS environment. Controls were ground reference strains of same bacterial species. Based on our results, some of the microorganisms are able to survive and proliferate on structural materials; the ability was greater in space isolates as compared with their ground analogs. The greatest ability to grow and proliferate on materials was demonstrated by Bacillus subtilis.

Maritime climate influence on chaparral composition and diversity in the coast range of central California.

PubMed

Vasey, Michael C; Parker, V Thomas; Holl, Karen D; Loik, Michael E; Hiatt, Seth

2014-09-01

We investigated the hypothesis that maritime climatic factors associated with summer fog and low cloud stratus (summer marine layer) help explain the compositional diversity of chaparral in the coast range of central California. We randomly sampled chaparral species composition in 0.1-hectare plots along a coast-to-interior gradient. For each plot, climatic variables were estimated and soil samples were analyzed. We used Cluster Analysis and Principle Components Analysis to objectively categorize plots into climate zone groups. Climate variables, vegetation composition and various diversity measures were compared across climate zone groups using ANOVA and nonmetric multidimensional scaling. Differences in climatic variables that relate to summer moisture availability and winter freeze events explained the majority of variance in measured conditions and coincided with three chaparral assemblages: maritime (lowland coast where the summer marine layer was strongest), transition (upland coast with mild summer marine layer influence and greater winter precipitation), and interior sites that generally lacked late summer water availability from either source. Species turnover (β-diversity) was higher among maritime and transition sites than interior sites. Coastal chaparral differs from interior chaparral in having a higher obligate seeder to facultative seeder (resprouter) ratio and by being dominated by various Arctostaphylos species as opposed to the interior dominant, Adenostoma fasciculatum. The maritime climate influence along the California central coast is associated with patterns of woody plant composition and β-diversity among sites. Summer fog in coastal lowlands and higher winter precipitation in coastal uplands combine to lower late dry season water deficit in coastal chaparral and contribute to longer fire return intervals that are associated with obligate seeders and more local endemism. Soil nutrients are comparatively less important in explaining plant community composition, but heterogeneous azonal soils contribute to local endemism and promote isolated chaparral patches within the dominant forest vegetation along the coast.

Agricultural matrices affect ground ant assemblage composition inside forest fragments

PubMed Central

Dos Santos, Iracenir Andrade; Ramos, Flavio Nunes; Majer, Jonathan David; Vilela, Evaldo Ferreira

2018-01-01

The establishment of agricultural matrices generally involves deforestation, which leads to fragmentation of the remaining forest. This fragmentation can affect forest dynamics both positively and negatively. Since most animal species are affected, certain groups can be used to measure the impact of such fragmentation. This study aimed to measure the impacts of agricultural crops (matrices) on ant communities of adjacent lower montane Atlantic rainforest fragments. We sampled nine forest fragments at locations surrounded by different agricultural matrices, namely: coffee (3 replicates); sugarcane (3); and pasture (3). At each site we installed pitfall traps along a 500 m transect from the interior of the matrix to the interior of the fragment (20 pitfall traps ~25 m apart). Each transect was partitioned into four categories: interior of the matrix; edge of the matrix; edge of the fragment; and interior of the fragment. For each sample site, we measured ant species richness and ant community composition within each transect category. Ant richness and composition differed between fragments and matrices. Each sample location had a specific composition of ants, probably because of the influence of the nature and management of the agricultural matrices. Species composition in the coffee matrix had the highest similarity to its corresponding fragment. The variability in species composition within forest fragments surrounded by pasture was greatest when compared with forest fragments surrounded by sugarcane or, to a lesser extent, coffee. Functional guild composition differed between locations, but the most representative guild was ‘generalist’ both in the agricultural matrices and forest fragments. Our results are important for understanding how agricultural matrices act on ant communities, and also, how these isolated forest fragments could act as an island of biodiversity in an ‘ocean of crops’. PMID:29791493

Agricultural matrices affect ground ant assemblage composition inside forest fragments.

PubMed

Assis, Diego Santana; Dos Santos, Iracenir Andrade; Ramos, Flavio Nunes; Barrios-Rojas, Katty Elena; Majer, Jonathan David; Vilela, Evaldo Ferreira

2018-01-01

The establishment of agricultural matrices generally involves deforestation, which leads to fragmentation of the remaining forest. This fragmentation can affect forest dynamics both positively and negatively. Since most animal species are affected, certain groups can be used to measure the impact of such fragmentation. This study aimed to measure the impacts of agricultural crops (matrices) on ant communities of adjacent lower montane Atlantic rainforest fragments. We sampled nine forest fragments at locations surrounded by different agricultural matrices, namely: coffee (3 replicates); sugarcane (3); and pasture (3). At each site we installed pitfall traps along a 500 m transect from the interior of the matrix to the interior of the fragment (20 pitfall traps ~25 m apart). Each transect was partitioned into four categories: interior of the matrix; edge of the matrix; edge of the fragment; and interior of the fragment. For each sample site, we measured ant species richness and ant community composition within each transect category. Ant richness and composition differed between fragments and matrices. Each sample location had a specific composition of ants, probably because of the influence of the nature and management of the agricultural matrices. Species composition in the coffee matrix had the highest similarity to its corresponding fragment. The variability in species composition within forest fragments surrounded by pasture was greatest when compared with forest fragments surrounded by sugarcane or, to a lesser extent, coffee. Functional guild composition differed between locations, but the most representative guild was 'generalist' both in the agricultural matrices and forest fragments. Our results are important for understanding how agricultural matrices act on ant communities, and also, how these isolated forest fragments could act as an island of biodiversity in an 'ocean of crops'.

22. INTERIOR VIEW WITH INTERIOR VIEW OF MOLDING SANDS CONTROL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. INTERIOR VIEW WITH INTERIOR VIEW OF MOLDING SANDS CONTROL AND TEST LAB FOR UNIT NO. 2 GREY IRON DISAMATIC. SAND CASTING TECHNICIAN, ROY BATES, TESTS THE WEIGHT OF THE SAND, DRYS IT, AND WEIGHT IT AGAINST STANDARDS TO CALCULATE THE CORRECT MOISTURE NEEDED FOR DIFFERENT MOLDS. THE SAND MIX VARY WITH THE SIZE AND COMPOSITION OF THE CASTING. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

Efectos del huracán Georges en la composición de especies y estructura de un bosque secundario en el interior de Puerto Rico

Treesearch

A.E. Lugo; C.M. Domínguez Cristóbal; N. Méndez Irizarry

2005-01-01

From 1995 to 2003 we studied species composition and structure in a secondary subtropical wet forest in Utuado Puerto Rico. During September 21-22, 1998, hurricane Georges passed through the stand with maximum sustained winds of 184 km/h and gusts of 240 km/h. Species richness increased after the hurricane. While native species Miconia prasina reduced its Importance...

Toward a mineral physics reference model for the Moon’s core

PubMed Central

Antonangeli, Daniele; Morard, Guillaume; Schmerr, Nicholas C.; Komabayashi, Tetsuya; Krisch, Michael; Fiquet, Guillaume; Fei, Yingwei

2015-01-01

The physical properties of iron (Fe) at high pressure and high temperature are crucial for understanding the chemical composition, evolution, and dynamics of planetary interiors. Indeed, the inner structures of the telluric planets all share a similar layered nature: a central metallic core composed mostly of iron, surrounded by a silicate mantle, and a thin, chemically differentiated crust. To date, most studies of iron have focused on the hexagonal closed packed (hcp, or ε) phase, as ε-Fe is likely stable across the pressure and temperature conditions of Earth’s core. However, at the more moderate pressures characteristic of the cores of smaller planetary bodies, such as the Moon, Mercury, or Mars, iron takes on a face-centered cubic (fcc, or γ) structure. Here we present compressional and shear wave sound velocity and density measurements of γ-Fe at high pressures and high temperatures, which are needed to develop accurate seismic models of planetary interiors. Our results indicate that the seismic velocities proposed for the Moon’s inner core by a recent reanalysis of Apollo seismic data are well below those of γ-Fe. Our dataset thus provides strong constraints to seismic models of the lunar core and cores of small telluric planets. This allows us to propose a direct compositional and velocity model for the Moon’s core. PMID:25775531

The chemical and isotopic differentiation of an epizonal magma body: Organ Needle pluton, New Mexico

USGS Publications Warehouse

Verplanck, P.L.; Farmer, G.L.; McCurry, M.; Mertzman, S.A.

1999-01-01

Major and trace element, and Nd and Sr isotopic compositions of whole rocks and mineral separates from the Oligocene, alkaline Organ Needle pluton (ONP), southern New Mexico, constrain models for the differentiation of the magma body parental to this compositionally zoned and layered epizonal intrusive body. The data reveal that the pluton is rimmed by lower ??(Nd) (~-5) and higher 87Sr/86Sr (~0.7085) syenitic rocks than those in its interior (??(Nd) ~ 2, 87Sr/86Sr ~0.7060) and that the bulk compositions of the marginal rocks become more felsic with decreasing structural depth. At the deepest exposed levels of the pluton, the ??(Nd)~-5 lithology is a compositionally heterogeneous inequigranular syenite. Modal, compositional and isotopic data from separates of rare earth element (REE)-bearing major and accesory mineral phases (hornblende, titanite, apatite, zircon) demonstrate that this decoupling of trace and major elements in the inequigranular syenite results from accumulation of light REE (LREE)-bearing minerals that were evidently separated from silicic magmas as the latter rose along the sides of the magma chamber. Chemical and isotopic data for microgranular mafic enclaves, as well as for restite xenoliths of Precambrian granite wall rock, indicate that the isotopic distinction between the marginal and interior facies of the ONP probably reflects assimilation of the wall rock by ??(Nd) ~-2 mafic magmas near the base of the magma system. Fractional crystallization and crystal liquid separation of the crystally contaminated magma at the base and along the margins of the chamber generated the highly silicic magmas that ultimately pooled at the chamber top.

Rheology, tectonics, and the structure of the Venus lithosphere

NASA Technical Reports Server (NTRS)

Zuber, M. T.

1994-01-01

Given the absence of ground truth information on seismic structure, heat flow, and rock strength, or short wavelength gravity or magnetic data for Venus, information on the thermal, mechanical and compositional nature of the shallow interior must be obtained by indirect methods. Using pre-Magellan data, theoretical models constrained by the depths of impact craters and the length scales of tectonic features yielded estimates on the thickness of Venus' brittle-elastic lithosphere and the allowable range of crustal thickness and surface thermal gradient. The purpose of this study is to revisit the question of the shallow structure of Venus based on Magellan observations of the surface and recent experiments that address Venus' crustal rheology.

Shielded high-Tc bscco tapes or wires for high field applications

DOEpatents

Balachandran, Uthamalingam; Lelovic, Milan; Eror, Nicholas G.

2002-01-01

A composite superconductor having an interior component of multiple filaments of superconducting Bi-2223 sheathed in a Ag or Ag alloy material, and a RE, TI or Hg based superconductor surrounding the interior component.

Shielded high-TC BSCCO tapes or wires for high field applications

DOEpatents

Balachandran, Uthamalingam; Lelovic, Milan; Eror, Nicholas G.

2001-01-01

A composite superconductor having an interior component of multiple filaments of superconducting Bi-2223 sheathed in a Ag or Ag alloy material, and a RE, TI or Hg based superconductor surrounding the interior component.

Bonding and structure in dense multi-component molecular mixtures

DOE PAGES

Meyer, Edmund R.; Ticknor, Christopher; Bethkenhagen, Mandy; ...

2015-10-30

We have performed finite-temperature density functional theory molecular dynamics simulations on dense methane, ammonia, and water mixtures (CH 4:NH 3:H 2O) for various compositions and temperatures (2000 K ≤ T ≤ 10000 K) that span a set of possible conditions in the interiors of ice-giant exoplanets. The equation-of-state, pair distribution functions, and bond autocorrelation functions (BACF) were used to probe the structure and dynamics of these complex fluids. In particular, an improvement to the choice of the cutoff in the BACF was developed that allowed analysis refinements for density and temperature effects. We note the relative changes in the naturemore » of these systems engendered by variations in the concentration ratios. As a result, a basic tenet emerges from all these comparisons that varying the relative amounts of the three heavy components (C,N,O) can effect considerable changes in the nature of the fluid and may in turn have ramifications for the structure and composition of various planetary layers.« less

Examination of interior surfaces using glow-discharge illumination

DOEpatents

Lord, David E.; Petrini, Richard R.; Carter, Gary W.

1978-01-01

Endoscopic examination of the interior of a hollow structure through a light pipe that is inserted into the structure, the interior being illuminated by means of a glow discharge that is established with a high voltage applied between the structure wall as one electrode and a second electrode that is inserted into the structure, or establishing the glow with two electrodes inserted into the structure.

Incorporation of organometallic Ru complexes into apo-ferritin cage.

PubMed

Takezawa, Yusuke; Böckmann, Philipp; Sugi, Naoki; Wang, Ziyue; Abe, Satoshi; Murakami, Tatsuya; Hikage, Tatsuo; Erker, Gerhard; Watanabe, Yoshihito; Kitagawa, Susumu; Ueno, Takafumi

2011-03-14

Spherical protein cages such as an iron storage protein, ferritin, have great potential as nanometer-scale capsules to assemble and store metal ions and complexes. We report herein the synthesis of a composite of an apo-ferritin cage and Ru(p-cymene) complexes. Ru complexes were efficiently incorporated into the ferritin cavity without degradation of its cage structure. X-Ray crystallography revealed that the Ru complexes were immobilized on the interior surface of the cage mainly by the coordination of histidine residues.

Mineralogy of chondritic interplanetary dust particle impact residues from LDEF

NASA Technical Reports Server (NTRS)

Barrett, R. A.; Zolensky, M. E.; Bernhard, R.

1993-01-01

A detailed structural and compositional analysis of several impactor residues was performed utilizing transmission electron microscopy, energy dispersive spectroscopy, and electron diffraction. Residues from the interior of several craters in gold surfaces were removed with a tungsten needle, mounted in EMBED-812 epoxy, and ultramicrotomed. The presence in these residues of equilibrated ferromagnesian minerals, recrystallization textures, glass, and melted metal and sulfide bodies decorating grain boundaries is indicative of varying degrees of shock metamorphism in all impact residues we have characterized.

VLT observations of the two Fermi pulsars PSR J1357$-$6429 and PSR J1048$-$5832

DOE PAGES

Mignani, R. P.; Shearer, A.; De Luca, A.; ...

2011-09-07

Optical observations of pulsars are crucial to studying the neutron star properties from the structure and composition of the interior to the properties and geometry of the magnetosphere. Historically, X and γ-ray observations have paved the way to pulsar optical identifications. Furthermore, the launch of the Fermi Gamma-ray Space Telescope opened new perspectives in the optical-to-γ-ray studies of neutron stars with the detection of more than 80 γ-ray pulsars.

Structure, composition and morphology of bioactive titanate layer on porous titanium surfaces

NASA Astrophysics Data System (ADS)

Li, Jinshan; Wang, Xiaohua; Hu, Rui; Kou, Hongchao

2014-07-01

A bioactive coating was produced on pore surfaces of porous titanium samples by an amendatory alkali-heat treatment method. Porous titanium was prepared by powder metallurgy and its porosity and average size were 45% and 135 μm, respectively. Coating morphology, coating structure and phase constituents were examined by SEM, XPS and XRD. It was found that a micro-network structure with sizes of <200 nm mainly composed of bioactive sodium titanate and rutile phases of TiO2 covered the interior and exterior of porous titanium cells, and redundant Ca ion was detected in the titanate layer. The concentration distribution of Ti, O, Ca and Na in the coating showed a compositional gradient from the intermediate layer toward the outer surface. These compositional gradients indicate that the coating bonded to Ti substrate without a distinct interface. After immersion into the SBF solution for 3 days, a bone-like carbonate-hydroxylapatite showing a good biocompatibility was detected on the coating surface. And the redundant Ca advanced the bioactivity of the coating. Thus, the present modification is expected to allow the use of the bioactive porous titanium as artificial bones even under load-bearing conditions.

Lunar Global Heat Flow: Predictions and Constraints

NASA Astrophysics Data System (ADS)

Siegler, M.; Williams, J. P.; Paige, D. A.; Feng, J.

2017-12-01

The global thermal state of the Moon provides fundamental information on its bulk composition and interior evolution. The Moon is known to have a highly asymmetric surface composition [e.g. Lawrence et al., 2003] and crustal thickness [Wieczorek et al.,2012], which is suspected to result from interior asymmetries [Wieczorek and Phillips, 2000; Laneuville et al., 2013]. This is likely to cause a highly asymmetric surface heat flux, both past and present. Our understanding the thermal evolution and composition of the bulk moon therefore requires a global picture of the present lunar thermal state, well beyond our two-point Apollo era measurement. As on the on the Earth, heat flow measurements need to be taken in carefully selected locations to truly characterize the state of the planet's interior. Future surface heat flux and seismic observations will be affected by the presence of interior temperature and crustal radiogenic anomalies, so placement of such instruments is critically important for understanding the lunar interior. The unfortunate coincidence that Apollo geophysical measurements lie areas within or directly abutting the highly radiogenic, anomalously thin-crusted Procellarum region highlights the importance of location for in situ geophysical study [e.g. Siegler and Smrekar, 2014]. Here we present the results of new models of global lunar geothermal heat flux. We synthesize data from several recent missions to constrain lunar crustal composition, thickness and density to provide global predictions of the surface heat flux of the Moon. We also discuss implications from new surface heat flux constraints from the LRO Diviner Lunar Radiometer Experiment and Chang'E 2 Microwave Radiometer. We will identify areas with the highest uncertainty to provide insight on the placement of future landed geophysical missions, such as the proposed Lunar Geophysical Network, to better aim our future exploration of the Moon.

43 CFR 1784.2-1 - Composition.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR GENERAL MANAGEMENT (1000) COOPERATIVE RELATIONS Advisory Committees § 1784.2-1... counsel and advice about public land and resource planning, retention, management and disposal. No person...

43 CFR 1784.2-1 - Composition.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR GENERAL MANAGEMENT (1000) COOPERATIVE RELATIONS Advisory Committees § 1784.2-1... counsel and advice about public land and resource planning, retention, management and disposal. No person...

43 CFR 1784.2-1 - Composition.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR GENERAL MANAGEMENT (1000) COOPERATIVE RELATIONS Advisory Committees § 1784.2-1... counsel and advice about public land and resource planning, retention, management and disposal. No person...

Preparation of sandwich-structured graphene/mesoporous silica composites with C8-modified pore wall for highly efficient selective enrichment of endogenous peptides for mass spectrometry analysis.

PubMed

Yin, Peng; Wang, Yuhua; Li, Yan; Deng, Chunhui; Zhang, Xiangmin; Yang, Pengyuan

2012-09-01

In this study, sandwich-structured graphene/mesoporous silica composites (C8-modified graphene@mSiO(2)) were synthesized by coating mesoporous silica onto hydrophilic graphene nanosheets through a surfactant-mediated cocondensation sol-gel process. The newly prepared C8-modified graphene@mSiO(2) nanocomposites possess unique properties of extended plate-like morphology, good water dispersibility, highly open pore structure, uniform pore size (2.8 nm), high surface area (632 m(2)/g), and C8-modified-interior pore walls. The unique structure of the C8-modified graphene@mSiO(2) composite nanosheets not only provide extended planes with hydrophilic surface that prevents aggregation in solution, but also offer a huge number of C8-modified mesopores with high surface area that can ensure an efficient adsorption of peptides through hydrophobic-hydrophobic interaction between C8-moified pore walls and target molecules. The obtained C8-modified graphene@mSiO(2) materials were utilized for size selectively and specifically enriching peptides in standard peptide mixtures and endogenous peptides in real biological samples (mouse brain tissue). © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Responses of Euglossine Bees (Hymenoptera, Apidae, Euglossina) to an Edge-Forest Gradient in a Large Tabuleiro Forest Remnant in Eastern Brazil.

PubMed

Coswosk, J A; Ferreira, R A; Soares, E D G; Faria, L R R

2018-08-01

Euglossine fauna of a large remnant of Brazilian Atlantic forest in eastern Brazil (Reserva Natural Vale) was assessed along an edge-forest gradient towards the interior of the fragment. To test the hypotheses that the structure of assemblages of orchid bees varies along this gradient, the following predictions were evaluated: (i) species richness is positively related to distance from the forest edge, (ii) species diversity is positively related to distance from the edge, (iii) the relative abundance of species associated with forest edge and/or open areas is inversely related to the distance from edge, and (iv) relative abundance of forest-related species is positively related to distance from the edge. A total of 2264 bees of 25 species was assessed at five distances from the edge: 0 m (the edge itself), 100 m, 500 m, 1000 m and 1500 m. Data suggested the existence of an edge-interior gradient for euglossine bees regarding species diversity and composition (considering the relative abundance of edge and forest-related species as a proxy for species composition) but not species richness.

Fundamental studies of structure borne noise for advanced turboprop applications

NASA Technical Reports Server (NTRS)

Eversman, W.; Koval, L. R.

1985-01-01

The transmission of sound generated by wing-mounted, advanced turboprop engines into the cabin interior via structural paths is considered. The structural model employed is a beam representation of the wing box carried into the fuselage via a representative frame type of carry through structure. The structure for the cabin cavity is a stiffened shell of rectangular or cylindrical geometry. The structure is modelled using a finite element formulation and the acoustic cavity is modelled using an analytical representation appropriate for the geometry. The structural and acoustic models are coupled by the use of hard wall cavity modes for the interior and vacuum structural modes for the shell. The coupling is accomplished using a combination of analytical and finite element models. The advantage is the substantial reduction in dimensionality achieved by modelling the interior analytically. The mathematical model for the interior noise problem is demonstrated with a simple plate/cavity system which has all of the features of the fuselage interior noise problem.

Entropy-theory-based study on the relationship between land use structure and industry system: a case study of the eastern Hubei metropolitan area

NASA Astrophysics Data System (ADS)

Su, Lilan; Liu, Yanfang; Gao, Xiaoyong

2009-10-01

During the process of economic growth, the industry structure transforms at different developing sections and that industrial composition as well as each department interior demand for land resources would reflect on land-use structure reform. This paper takes Hubei as the research zone, through a consecutive time sequence of 10 years period (1996-2005) just before and after the 1 plus 8 Eastern Hubei Metropolitan Area project, a quantitative study of the correlation between the industry structure and land-use structure is made based on the entropy theory. According to the classification of industrial composition, the land-use structure here is also redefined into four types as Land Use for Primary Industry, Land Use for Secondary Industry, Land Use for Tertiary Industry, and Land Use for Potential Reserve, in the aim that it should model new methods for researching the relationship of industry structure and land-use structure, and the instinct driving force would be presented more evidently at the same time. The outcomes indicate that the change of land-use structure has close relationship with the structure of industry composition; the trend of information entropy in Hubei mostly keeps increasing during the past 10 years which predicating the symmetrical degree of land-use structure is gradually built; and Eastern Hubei Metropolitan Area is of favorable power far superiority other units within province in promoting regional development, yet land-use structure adjustments are still not stable and a optimal mode of land use needs further approach.

The Ganymede Interior Structure, and Magnetosphere Observer (GISMO) Mission Concept

NASA Technical Reports Server (NTRS)

Lynch, K. L.; Smith, I. B.; Singer, K. N.; Vogt, M. F.; Blackburn, D. G.; Chaffin, M.; Choukroun, M.; Ehsan, N.; DiBraccio, G. A.; Gibbons, L. J.;

Water and the Interior Structure of Terrestrial Planets and Icy Bodies

NASA Astrophysics Data System (ADS)

Monteux, J.; Golabek, G. J.; Rubie, D. C.; Tobie, G.; Young, E. D.

2018-02-01

Water content and the internal evolution of terrestrial planets and icy bodies are closely linked. The distribution of water in planetary systems is controlled by the temperature structure in the protoplanetary disk and dynamics and migration of planetesimals and planetary embryos. This results in the formation of planetesimals and planetary embryos with a great variety of compositions, water contents and degrees of oxidation. The internal evolution and especially the formation time of planetesimals relative to the timescale of radiogenic heating by short-lived 26Al decay may govern the amount of hydrous silicates and leftover rock-ice mixtures available in the late stages of their evolution. In turn, water content may affect the early internal evolution of the planetesimals and in particular metal-silicate separation processes. Moreover, water content may contribute to an increase of oxygen fugacity and thus affect the concentrations of siderophile elements within the silicate reservoirs of Solar System objects. Finally, the water content strongly influences the differentiation rate of the icy moons, controls their internal evolution and governs the alteration processes occurring in their deep interiors.

Correlating structural dynamics and catalytic activity of AgAu nanoparticles with ultrafast spectroscopy and all-atom molecular dynamics simulations.

PubMed

Ferbonink, G F; Rodrigues, T S; Dos Santos, D P; Camargo, P H C; Albuquerque, R Q; Nome, R A

2018-05-29

In this study, we investigated hollow AgAu nanoparticles with the goal of improving our understanding of the composition-dependent catalytic activity of these nanoparticles. AgAu nanoparticles were synthesized via the galvanic replacement method with controlled size and nanoparticle compositions. We studied extinction spectra with UV-Vis spectroscopy and simulations based on Mie theory and the boundary element method, and ultrafast spectroscopy measurements to characterize decay constants and the overall energy transfer dynamics as a function of AgAu composition. Electron-phonon coupling times for each composition were obtained from pump-power dependent pump-probe transients. These spectroscopic studies showed how nanoscale surface segregation, hollow interiors and porosity affect the surface plasmon resonance wavelength and fundamental electron-phonon coupling times. Analysis of the spectroscopic data was used to correlate electron-phonon coupling times to AgAu composition, and thus to surface segregation and catalytic activity. We have performed all-atom molecular dynamics simulations of model hollow AgAu core-shell nanoparticles to characterize nanoparticle stability and equilibrium structures, besides providing atomic level views of nanoparticle surface segregation. Overall, the basic atomistic and electron-lattice dynamics of core-shell AgAu nanoparticles characterized here thus aid the mechanistic understanding and performance optimization of AgAu nanoparticle catalysts.

Constraining the volatile fraction of planets from transit observations

NASA Astrophysics Data System (ADS)

Alibert, Y.

2016-06-01

Context. The determination of the abundance of volatiles in extrasolar planets is very important as it can provide constraints on transport in protoplanetary disks and on the formation location of planets. However, constraining the internal structure of low-mass planets from transit measurements is known to be a degenerate problem. Aims: Using planetary structure and evolution models, we show how observations of transiting planets can be used to constrain their internal composition, in particular the amount of volatiles in the planetary interior, and consequently the amount of gas (defined in this paper to be only H and He) that the planet harbors. We first explore planets that are located close enough to their star to have lost their gas envelope. We then concentrate on planets at larger distances and show that the observation of transiting planets at different evolutionary ages can provide statistical information on their internal composition, in particular on their volatile fraction. Methods: We computed the evolution of low-mass planets (super-Earths to Neptune-like) for different fractions of volatiles and gas. We used a four-layer model (core, silicate mantle, icy mantle, and gas envelope) and computed the internal structure of planets for different luminosities. With this internal structure model, we computed the internal and gravitational energy of planets, which was then used to derive the time evolution of the planet. Since the total energy of a planet depends on its heat capacity and density distribution and therefore on its composition, planets with different ice fractions have different evolution tracks. Results: We show for low-mass gas-poor planets that are located close to their central star that assuming evaporation has efficiently removed the entire gas envelope, it is possible to constrain the volatile fraction of close-in transiting planets. We illustrate this method on the example of 55 Cnc e and show that under the assumption of the absence of gas, the measured mass and radius imply at least 20% of volatiles in the interior. For planets at larger distances, we show that the observation of transiting planets at different evolutionary ages can be used to set statistical constraints on the volatile content of planets. Conclusions: These results can be used in the context of future missions like PLATO to better understand the internal composition of planets, and based on this, their formation process and potential habitability.

Control of Electronic Structures and Phonon Dynamics in Quantum Dot Superlattices by Manipulation of Interior Nanospace.

PubMed

Chang, I-Ya; Kim, DaeGwi; Hyeon-Deuk, Kim

2016-07-20

Quantum dot (QD) superlattices, periodically ordered array structures of QDs, are expected to provide novel photo-optical functions due to their resonant couplings between adjacent QDs. Here, we computationally demonstrated that electronic structures and phonon dynamics of a QD superlattice can be effectively and selectively controlled by manipulating its interior nanospace, where quantum resonance between neighboring QDs appears, rather than by changing component QD size, shape, compositions, etc. A simple H-passivated Si QD was examined to constitute one-, two-, and three-dimensional QD superlattices, and thermally fluctuating band energies and phonon modes were simulated by finite-temperature ab initio molecular dynamics (MD) simulations. The QD superlattice exhibited a decrease in the band gap energy enhanced by thermal modulations and also exhibited selective extraction of charge carriers out of the component QD, indicating its advantage as a promising platform for implementation in solar cells. Our dynamical phonon analyses based on the ab initio MD simulations revealed that THz-frequency phonon modes were created by an inter-QD crystalline lattice formed in the QD superlattice, which can contribute to low energy thermoelectric conversion and will be useful for direct observation of the dimension-dependent superlattice. Further, we found that crystalline and ligand-originated phonon modes inside each component QD can be independently controlled by asymmetry of the superlattice and by restriction of the interior nanospace, respectively. Taking into account the thermal effects at the finite temperature, we proposed guiding principles for designing efficient and space-saving QD superlattices to develop functional photovoltaic and thermoelectric devices.

Structure and Evolution of Kuiper Belt Objects: The Case for Compositional Classes

NASA Astrophysics Data System (ADS)

McKinnon, William B.; Prialnik, D.; Stern, S. A.

2007-10-01

Kuiper belt objects (KBOs) accreted from a mélange of ices, carbonaceous matter, and rock of mixed interstellar and solar nebular provenance. The transneptunian region, where this accretion took place, was likely more radially compact than today. This and the influence of gas drag during the solar nebula epoch argue for more rapid KBO accretion than usually considered. Early evolution of KBOs was largely the result of radiogenic heating, with both short-term and long-term contributions being potentially important. Depending on rock content and porous conductivity, KBO interiors may have reached relatively high temperatures. Models suggest that KBOs likely lost very volatile ices during early evolution, whereas less volatile ices should be retained in cold, less altered subsurface layers; initially amorphous ice may have crystallized in the interior as well, releasing trapped volatiles. Generally, KBOs should be stratified in terms of composition and porosity, albeit subject to impact disruption and collisional stripping. KBOs are thus unlikely to be "the most pristine objects in the Solar System.” Large (dwarf planet) KBOs may be fully differentiated. KBO surface color and compositional classes are usually discussed in terms of "nature vs. nurture,” i.e., a generic primordial composition vs. surface processing, but the true nature of KBOs also depends on how they have evolved. The broad range of albedos now found in the Kuiper belt, deep water-ice absorptions on some objects, evidence for differentiation of Pluto and 2003 EL61, and a range of densities incompatible with a single, primordial composition and variable porosity strongly imply significant, intrinsic compositional differences among KBOs. The interplay of formation zone (accretion rate), body size, and dynamical (collisional) history may yield KBO compositional classes (and their spectral correlates) that recall the different classes of asteroids in the inner Solar System, but whose members are broadly distributed among the KBO dynamical subpopulations.

The Influences of Lamination Angles on the Interior Noise Levels of an Aircraft

NASA Technical Reports Server (NTRS)

Fernholz, Christian M.; Robinson, Jay H.

1996-01-01

The feasibility of reducing the interior noise levels of an aircraft passenger cabin through optimization of the composite lay up of the fuselage is investigated. MSC/NASTRAN, a commercially available finite element code, is used to perform the dynamic analysis and subsequent optimization of the fuselage. The numerical calculation of sensitivity of acoustic pressure to lamination angle is verified using a simple thin, cylindrical shell with point force excitations as noise sources. The thin shell used represents a geometry similar to the fuselage and analytic solutions are available for the cylindrical thin shell equations of motion. Optimization of lamination angle for the reduction of interior noise is performed using a finite element model of an actual aircraft fuselage. The aircraft modeled for this study is the Beech Starship. Point forces simulate the structure borne noise produced by the engines and are applied to the fuselage at the wing mounting locations. These forces are the noise source for the optimization problem. The acoustic pressure response is reduced at a number of points in the fuselage and over a number of frequencies. The objective function is minimized with the constraint that it be larger than the maximum sound pressure level at the response points in the passenger cabin for all excitation frequencies in the range of interest. Results from the study of the fuselage model indicate that a reduction in interior noise levels is possible over a finite frequency range through optimal configuration of the lamination angles in the fuselage. Noise reductions of roughly 4 dB were attained. For frequencies outside the optimization range, the acoustic pressure response may increase after optimization. The effects of changing lamination angle on the overall structural integrity of the airframe are not considered in this study.

Vegetation response to stand structure and prescribed fire in an interior ponderosa pine ecosystem

Treesearch

Jianwei Zhang; Martin W. Ritchie; William W. Oliver

2008-01-01

A large-scale interior ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) study was conducted at the Blacks Mountain Experimental Forest in northeastern California. The primary purpose of the study was to determine the influence of structural diversity on the dynamics of interior pine forests at the landscape scale. High structural...

A Review: Enhanced Anodes of Li/Na-Ion Batteries Based on Yolk-Shell Structured Nanomaterials

NASA Astrophysics Data System (ADS)

Wu, Cuo; Tong, Xin; Ai, Yuanfei; Liu, De-Sheng; Yu, Peng; Wu, Jiang; Wang, Zhiming M.

2018-09-01

Lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) have received much attention in energy storage system. In particular, among the great efforts on enhancing the performance of LIBs and SIBs, yolk-shell (YS) structured materials have emerged as a promising strategy toward improving lithium and sodium storage. YS structures possess unique interior void space, large surface area and short diffusion distance, which can solve the problems of volume expansion and aggregation of anode materials, thus enhancing the performance of LIBs and SIBs. In this review, we present a brief overview of recent advances in the novel YS structures of spheres, polyhedrons and rods with controllable morphology and compositions. Enhanced electrochemical performance of LIBs and SIBs based on these novel YS structured anode materials was discussed in detail. [Figure not available: see fulltext.

Polypyrrole/poly (p-phenylene terephthalamide) composite fibers: Morphology, mechanics, and electrical properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rector, L.P.

1991-01-01

Polypyrrole/poly (p-phenylene terephthalamide) (PPTA) composite fibers were fabricated by the oxidative polymerization of pyrrole within the gel structure of never-dried, dry-jet, wet-spun PPTA fibers. The composites were formed by infiltration of the swollen PPTA fibers with the chemical oxidant FeCl{sub 3}, followed by exposure of the infiltrated fibers to pyrrole vapor at elevated temperatures (100C). The conductive phase volume fraction was controlled by variations in the FeCl{sub 3} infiltration concentration. The temperature dependencies of the composite fiber d.c. conductivities is reasonably well described by the predictions of the three-dimensional variable-range hoping (3DVRH) charge transport model. The composite morphology was examinedmore » with SEM results demonstrating the existence of micron-sized polypyrrole inclusions in the fiber interior, as well as a polypyrrole skin on the fiber surface. The tensile modulii of the composite fibers exhibited a rule-of-mixtures dependence upon PPTA content. The compressive properties of several composite-fiber compositions were evaluated by the elastica loop method. The compressive strengths were found to be 82-151% of the corresponding ultimate tensile strengths.« less

Physics-Based Simulation and Experiment on Blast Protection of Infill Walls and Sandwich Composites Using New Generation of Nano Particle Reinforced Materials

NASA Astrophysics Data System (ADS)

Irshidat, Mohammad

A critical issue for the development of nanotechnology is our ability to understand, model, and simulate the behavior of small structures and to make the connection between nano structure properties and their macroscopic functions. Material modeling and simulation helps to understand the process, to set the objectives that could guide laboratory efforts, and to control material structures, properties, and processes at physical implementation. These capabilities are vital to engineering design at the component and systems level. In this research, experimental-computational-analytical program was employed to investigate the performance of the new generation of polymeric nano-composite materials, like nano-particle reinforced elastomeric materials (NPREM), for the protection of masonry structures against blast loads. New design tools for using these kinds of materials to protect Infill Walls (e.g. masonry walls) against blast loading were established. These tools were also extended to cover other type of panels like sandwich composites. This investigation revealed that polymeric nano composite materials are strain rate sensitive and have large amount of voids distributed randomly inside the materials. Results from blast experiments showed increase in ultimate flexural resistance achieved by both unreinforced and nano reinforced polyurea retrofit systems applied to infill masonry walls. It was also observed that a thin elastomeric coating on the interior face of the walls could be effective at minimizing the fragmentation resulting from blast. More conclusions are provided with recommended future research.

Hot-start Giant Planets Form with Radiative Interiors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berardo, David; Cumming, Andrew, E-mail: david.berardo@mcgill.ca, E-mail: andrew.cumming@mcgill.ca

In the hot-start core accretion formation model for gas giants, the interior of a planet is usually assumed to be fully convective. By calculating the detailed internal evolution of a planet assuming hot-start outer boundary conditions, we show that such a planet will in fact form with a radially increasing internal entropy profile, so that its interior will be radiative instead of convective. For a hot outer boundary, there is a minimum value for the entropy of the internal adiabat S {sub min} below which the accreting envelope does not match smoothly onto the interior, but instead deposits high entropymore » material onto the growing interior. One implication of this would be to at least temporarily halt the mixing of heavy elements within the planet, which are deposited by planetesimals accreted during formation. The compositional gradient this would impose could subsequently disrupt convection during post-accretion cooling, which would alter the observed cooling curve of the planet. However, even with a homogeneous composition, for which convection develops as the planet cools, the difference in cooling timescale will change the inferred mass of directly imaged gas giants.« less

Prediction for the Flow-induced Gravity Field of Saturn: Implications for Cassini’s Grand Finale

NASA Astrophysics Data System (ADS)

Galanti, Eli; Kaspi, Yohai

2017-07-01

The Cassini measurements of Saturn’s gravity field during its Grand Finale might shed light on a long-standing question regarding the flow on Saturn. While the cloud-level winds are well known, little is known about whether these winds are confined to the outer layers of the planet or penetrate deep into the interior. An additional complexity is added by the uncertainty in the exact rotation period of Saturn, a key factor in determining the cloud-level winds, with an effect on the north-south symmetric part of the winds. Using Saturn’s cloud-level winds we relate the flow to the gravity harmonics. We give a prediction for the odd harmonics {J}3,{J}5,{J}7,{and} {J}9 as a function of the flow depth, identifying three ranges of depths. Since the odd harmonics depend solely on the flow, and are not influenced by Saturn’s shape and static density distribution, any measured value of the odd harmonics by Cassini can be used to uniquely determine the depth of the flow. We also discuss the flow-induced even harmonics {{Δ }}{J}2,{{Δ }}{J}4,\\ldots ,{{Δ }}{J}12 that are affected by Saturn’s rotation period. While the high-degree even harmonics might also be used to determine the flow depth, the lower-degree even harmonics serve as uncertainties for analysis of the planet’s interior structure and composition. Thus, the gravity harmonics measured during the Cassini Grand Finale may be used to get a first-order estimate of the flow structure and to better constrain the planet’s density structure and composition.

Continental Scientific Drilling and Exploration Act. Introduced in the Senate, Ninety-Ninth Congress, Second Session, September 19, 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-01-01

The Senate Committee on Energy and Natural Resources report on S. 1026 recommends without amendment the bill which directs the Secretaries of the Interior and the National Science Foundation to cooperate in implementing the Continental Scientific Drilling Program (CSDP). The purpose of the CSDP is to enhance the knowledge and understanding of the composition, structure, dynamics, and evolution of the continental crust, including how such processes affect natural phenomena. The report includes background and the need for the legislation and summarizes the four sections.

Active control of interior noise in model aircraft fuselages using piezoceramic actuators

NASA Technical Reports Server (NTRS)

Fuller, C. R.; Hansen, C. H.; Silcox, R. J.; Snyder, S. D.

1990-01-01

Active control of interior noise in model aircraft fuselages using piezoceramic actuators is experimentally studied. The actuators are bonded directly to the structure and error information is taken from up to two microphones located in the interior acoustic field. The results demonstrate that global attenuation of the order of 10 to 15 dB of interior noise can be achieved with piezoceramic actuators, irrespective of whether the shell system is vibrating at an acoustic or structural resonant frequency. The work also proves that active control using vibration (moment) inputs works well when a floor simulating that of an aircraft is installed in the model. This result suggests that the technique will be successful in controlling interior noise in realistic aircraft structures.

Review of natural fiber composites

NASA Astrophysics Data System (ADS)

Rohan, T.; Tushar, B.; T, Mahesha G.

2018-02-01

Development of new alternative materials to the existing traditional metals, alloys and synthetic materials is the new buzz in recent research activities at the academic and industrial level taking place all over the world. Earning carbon credits by minimizing the atmospheric pollution is getting an increase in attention by industries. One small step to conserve the atmosphere around us is to use natural resources in making fully bio degradable or partially bio degradable composite materials. Such prepared alternative materials can find applications in interior housing, automotive, marine, domestic, and other applications. Composites made by using appropriate natural fibers as reinforcements is a possibility that ensures such a reality as they can be well received in multiple disciplines of engineering. Results published from various research activities illustrates that natural fiber composites can successfully be adapted for non-structural, moderate load bearing indoor applications. Further, the few deficiencies in the natural fibers can be overcome by subjecting them to morphological changes by various physical or chemical treatment methods. The overall objective of this paper is to provide a comprehensive overview of the property profiles of Natural Fiber Composites.

View towards east of interior wall structure with parts of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View towards east of interior wall structure with parts of coffee despulpadora in foreground - Finca Silem, Coffee Processing Structure No. 1, Highway 139, Kilometer 9.3, Maraguez, Ponce Municipio, PR

Self-templated formation of uniform NiCo2O4 hollow spheres with complex interior structures for lithium-ion batteries and supercapacitors.

PubMed

Shen, Laifa; Yu, Le; Yu, Xin-Yao; Zhang, Xiaogang; Lou, Xiong Wen David

2015-02-02

Despite the significant advancement in preparing metal oxide hollow structures, most approaches rely on template-based multistep procedures for tailoring the interior structure. In this work, we develop a new generally applicable strategy toward the synthesis of mixed-metal-oxide complex hollow spheres. Starting with metal glycerate solid spheres, we show that subsequent thermal annealing in air leads to the formation of complex hollow spheres of the resulting metal oxide. We demonstrate the concept by synthesizing highly uniform NiCo2O4 hollow spheres with a complex interior structure. With the small primary building nanoparticles, high structural integrity, complex interior architectures, and enlarged surface area, these unique NiCo2O4 hollow spheres exhibit superior electrochemical performances as advanced electrode materials for both lithium-ion batteries and supercapacitors. This approach can be an efficient self-templated strategy for the preparation of mixed-metal-oxide hollow spheres with complex interior structures and functionalities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Just the Right Amount of Reinforcement

NASA Technical Reports Server (NTRS)

Walton, Greg

1998-01-01

Lockheed Martin Skunk Works, is taking the next step towards economical low-Earth-orbit (LEO) operations with NASA's X-33 technology demonstrator, that uses composite tanks for liquid hydrogen (LH sub2) fuel storage and structural support, The X-33 is a 53% scale model of the VentureStar single-stage-to-orbit (SSTO) reusable launch vehicle(RLV) projected to orbit payloads at a rate, of $1,000 per pound beginning in 2004 In order to make VentureStar completely reusable and economical engineers are using composite materials throughout the spacecrafts structure. The first test of the design comes in 1999 on the X-33 technology demonstrator. Two of the primary structures that engineers will be evaluating are the carbon fiber/epoxy LH2 fuel tanks. The 29-ft long by 18-ft wide tanks, which fill two-thirds of the X-33's interior, serve a dual purpose carrying fuel and providing structural support to the walls of the spacecraft. Fiber placement makes it possible to build the fuel tanks, large, light and strong enough to satisfy X33's requirements. Lockheed Martin choose the fabrication technology to produce the eight sections of each tank because of fiber placement's ability to handle complex surfaces, speed and repeatability.

Facile synthesis of nanorod-assembled multi-shelled Co3O4 hollow microspheres for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Wang, Yaping; Pan, Anqiang; Zhu, Qinyu; Nie, Zhiwei; Zhang, Yifang; Tang, Yan; Liang, Shuquan; Cao, Guozhong

2014-12-01

In this work, we report a novel strategy for the controlled synthesis of nanorod assembled multi-shelled cobalt oxide (Co3O4) hollow microspheres (HSs). The Co2CO3(OH)2 NRs are first vertically grown on the carbon microspheres (CS) to form the core-shelled composites by a low-temperature solution route. The multi-shelled hollow interiors within the Co3O4 microspheres are unconventionally obtained by annealing the as-prepared core-shell structured CS@Co2CO3(OH)2 composite in air. When evaluated for supercapacitive performance, the multi-shelled Co3O4 hollow microspheres exhibit high capacitance of 394.4 and 360 F g-1 at the current densities of 2 A g-1 and 10 A g-1, respectively. The superior electrochemical performance can be attributed to the multi-shelled hollow structures, which facilitate the electrolyte penetration and provide more active sites for the electrochemical reactions.

Surface emission from neutron stars and implications for the physics of their interiors.

PubMed

Ozel, Feryal

2013-01-01

Neutron stars are associated with diverse physical phenomena that take place in conditions characterized by ultrahigh densities as well as intense gravitational, magnetic and radiation fields. Understanding the properties and interactions of matter in these regimes remains one of the challenges in compact object astrophysics. Photons emitted from the surfaces of neutron stars provide direct probes of their structure, composition and magnetic fields. In this review, I discuss in detail the physics that governs the properties of emission from the surfaces of neutron stars and their various observational manifestations. I present the constraints on neutron star radii, core and crust composition, and magnetic field strength and topology obtained from studies of their broadband spectra, evolution of thermal luminosity, and the profiles of pulsations that originate on their surfaces.

Interior view of coffee processing structure No. 1, showing concrete ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior view of coffee processing structure No. 1, showing concrete reservoirs on floor, view towards the west - Finca Silem, Coffee Processing Structure No. 1, Highway 139, Kilometer 9.3, Maraguez, Ponce Municipio, PR

Titan's Interior Chemical Composition: A Thermochemical Assessment*

NASA Astrophysics Data System (ADS)

Howard, Michael; Zaug, J. M.; Khare, B. N.; McKay, C. P.

2007-10-01

We study the interior composition of Titan using thermal chemical equilibrium calculations that are valid to high pressures and temperatures. The equations of state are based on exponential-6 fluid theory and have been validated against experimental data up to a few Mbars in pressure and approximately 20000K in temperature. In addition to CHNO molecules, we account for multi-phases of carbon, water and a variety of metals such as Al and Fe, and their oxides. With these fluid equations of state, chemical equilibrium is calculated for a set of product species. As the temperature and pressure evolves for increasing depth in the interior, the chemical equilibrium shifts. We assume that Titan is initially composed of comet material, which we assume to be solar, except for hydrogen, which we take to be depleted by a factor 1/690. We find that a significant amount of nitrogen is in the form of n2, rather than nh3. Moreover, above 12 kbars, as is the interior pressure of Titan, a significant amount of the carbon is in the form of graphite, rather than co2 and ch4. We discuss the implications of these results for understanding the atmospheric and surface composition of Titan. • This work was performed under the auspices of the U.S. Department of Energy by the University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Titan's Interior Chemical Composition: Possible Important Phase Transitions

NASA Astrophysics Data System (ADS)

Howard, Michael; Fried, L. E.; Khare, B. N.; McKay, C. P.

2008-09-01

We study the interior composition of Titan using thermal chemical equilibrium calculations that are valid to high pressures and temperatures. The equations of state are based on exponential-6 fluid theory and have been validated against experimental data up to a few Mbars in pressure and approximately 20000K in temperature. In addition to CHNO molecules, we account for multi-phases of carbon, water and a variety of metals such as Al and Fe, and their oxides. With these fluid equations of state, chemical equilibrium is calculated for a set of product species. As the temperature and pressure evolves for increasing depth in the interior, the chemical equilibrium shifts. We assume that Titan is initially composed of comet material, which we assume to be solar, except for hydrogen, which we take to be depleted by a factor 1/1000. We find that a significant amount of nitrogen is in the form of N2, rather than NH3. Moreover, above 12 kbars pressure, as is the interior pressure of Titan, a significant amount of the carbon is in the form of graphite, rather than CO2 and CH4. We discuss the implications of these results for understanding the atmospheric and surface composition of Titan. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Geomorphic Terrains and Evidence for Ancient Volcanism within Northeastern South Pole-Aitken Basin

NASA Technical Reports Server (NTRS)

Petro, Noah; Mest, Scott C.; Teich, Yaron

2010-01-01

The interior of the enigmatic South Pole-Aitken Basin has long been recognized as being compositionally distinct from its exterior. However, the source of the compositional anomaly has been subject to some debate. Is the source of the iron-enhancement due to lower-crustal/upper-mantle material being exposed at the surface, or was there some volume of ancient volcanism that covered portions of the basin interior? While several obvious mare basalt units are found within the basin and regions that appear to represent the original basin interior, there are several regions that appear to have an uncertain origin. Using a combination of Clementine and Lunar Orbiter images, several morphologic units are defined based on albedo, crater density, and surface roughness. An extensive unit of ancient mare basalt (cryptomare) is defined and, based on the number of superimposed craters, potentially represents the oldest volcanic materials within the basin. Thus, the overall iron-rich interior of the basin is not solely due to deeply derived crustal material, but is, in part due to the presence of ancient volcanic units.

Process engineering of polynanomeric layered and infused composites

NASA Astrophysics Data System (ADS)

Williams, Ebonee Porche Marie

As the application of advanced polymeric composites expands, the continued adaptation of traditional as well as the incorporation and/or implementation of new technologies continue to be at the core of development for engineers. One of these traditional technologies is honeycomb sandwich composites. This technology has been around for more than fifty years and there have been minimal alterations to the materials used to produce the parts and the process used to manufacture the structures. This is where the depth of this work focused. Traditional honeycomb core dip resin systems were modified to incorporate nano scale fillers. This adaptation is one of the defining aspects of polynanomeric systems, the concept of which is that modifications of the nano scale in a polymer system create nano layered structures that emulate the properties of both the polymer and the nano filler, a nano composite. The modified resin systems were characterized to investigate morphology, thermal and mechanical properties as well as electrical characteristics. It was observed that the nano altered resin system exhibited increased mechanical, 50 to 60%, and thermal properties, burn temperatures extended by 30°C, while also demonstrating improved electrical properties. These were significant results given that the main applications of honeycomb sandwich structures are on the interior of aircrafts. These results could open the door to some new applications of the modified resin system. This work also implemented a new processing technique to produce honeycomb sandwich structures. The technique was Vacuum Assisted Resin Transfer Molding, VARTM, which has gained interest over the last decade due to the reduced up front cost to initiate production, the ease of processing, and the overall health benefits. This process was successfully performed to produce sandwich structures by incorporating a permeable scrim layer at the core face sheet interface. This was the first successful production of unfilled honeycomb core sandwich part production. Overall this work is at the tip of implementing new materials and processing techniques into honeycomb core and honeycomb sandwich composite structures.

INTERIOR; DETAIL OF ROOF FRAMING STRUCTURE, LOOKING SOUTHWEST. Naval ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR; DETAIL OF ROOF FRAMING STRUCTURE, LOOKING SOUTHWEST. - Naval Computer & Telecommunications Area Master Station, Eastern Pacific, Radio Transmitter Facility Lualualei, Helix House No. 2, Base of Radio Antenna Structure No. 427, Makaha, Honolulu County, HI

Oxygen Fugacity in Large Metal Capsules

NASA Astrophysics Data System (ADS)

Faul, U.; Cline, C. J., II; Jackson, I.; Berry, A.

2016-12-01

During experiments with iron bearing silicates, equilibration between metal capsules and sample interior depends on diffusion of Fe if the capsule composition is not initially in equilibrium with the sample composition. For example, placing Pt or Ni capsules in contact with Fe-bearing olivine leads to Fe-loss from the olivine. In a fully equilibrated system the Fe contents of coexisting metal capsule and olivine reflect the oxygen fugacity (fO2) of the system. Experiments were conducted with olivine encapsulated or wrapped in four different metals (Fe, Ni70Fe30, Ni and Pt) to determine the fO2 in the cm-sized samples used for deformation and seismic property experiments. Small Pt particles mixed with olivine powder were used as fO2 sensors in the interior of the capsules. The results show an ordering of the fO2 in the interior that is consistent with the enclosing metals, i.e. the fO2 is lowest in a Fe capsule and highest in a Pt capsule. However, fO2 values in the more oxidizing metal capsules are substantially below their respective metal-oxide buffers. For example, solgel olivine encapsulated in Ni has an oxygen fugacity that is more than three orders of magnitude below Ni-NiO at 1200C and 0.3 GPa. The fO2 in a capsule interior is therefore to some extent self-buffering and only moderately influenced by the composition of the capsule. While the Pt particles in the interior are equilibrated, Fe gradients from the interior up to the Pt and Ni sample-capsule interfaces show that Fe loss into the capsules is diffusion limited. The fO2 at the interface also has implications for the water retention in unbuffered capsules. We infer that relatively high fO2 and hence fH2O observed adjacent to Pt capsules enables retention of water in these capsules, but the fO2 adjacent to Ni capsules is too low and water is lost.

High temperature cooling system and method

DOEpatents

Loewen, Eric P.

2006-12-12

A method for cooling a heat source, a method for preventing chemical interaction between a vessel and a cooling composition therein, and a cooling system. The method for cooling employs a containment vessel with an oxidizable interior wall. The interior wall is oxidized to form an oxide barrier layer thereon, the cooling composition is monitored for excess oxidizing agent, and a reducing agent is provided to eliminate excess oxidation. The method for preventing chemical interaction between a vessel and a cooling composition involves introducing a sufficient quantity of a reactant which is reactive with the vessel in order to produce a barrier layer therein that is non-reactive with the cooling composition. The cooling system includes a containment vessel with oxidizing agent and reducing agent delivery conveyances and a monitor of oxidation and reduction states so that proper maintenance of a vessel wall oxidation layer occurs.

Pb-, Sr- and Nd-Isotopic systematics and chemical characteristics of cenozoic basalts, Eastern China

USGS Publications Warehouse

Peng, Z.C.; Zartman, R.E.; Futa, K.; Chen, D.G.

1986-01-01

Forty-eight Paleogene, Neogene and Quaternary basaltic rocks from northeastern and east-central China have been analyzed for major-element composition, selected trace-element contents, and Pb, Sr and Nd isotopic systematics. The study area lies entirely within the marginal Pacific tectonic domain. Proceeding east to west from the continental margin to the interior, the basalts reveal an isotopic transition in mantle source material and/or degree of crustal interaction. In the east, many of the rocks are found to merge both chemically and isotopically with those previously reported from the Japanese and Taiwan island-arc terrains. In the west, clear evidence exists for component(s) of Late Archean continental lithosphere to be present in some samples. A major crustal structure, the Tan-Lu fault, marks the approximate boundary between continental margin and interior isotopic behaviors. Although the isotopic signature of the western basalts has characteristics of lower-crustal contamination, a subcrustal lithosphere, i.e. an attached mantle keel, is probably more likely to be the major contributor of their continental "flavor". The transition from continental margin to interior is very pronounced for Pb isotopes, although Sr and Nd isotopes also combine to yield correlated patterns that deviate strikingly from the mid-ocean ridge basalt (MORB) and oceanic-island trends. The most distinctive chemical attribute of this continental lithosphere component is its diminished U Pb as reflected in the Pb isotopic composition when compared to sources of MORB, oceanic-island and island-arc volcanic rocks. Somewhat diminished Sm Nd and elevated Rb Sr, especially in comparison to the depleted asthenospheric mantle, are also apparent from the Nd- and Sr-isotopic ratios. ?? 1986.

Mosquito communities and disease risk influenced by land use change and seasonality in the Australian tropics.

PubMed

Meyer Steiger, Dagmar B; Ritchie, Scott A; Laurance, Susan G W

2016-07-07

Anthropogenic land use changes have contributed considerably to the rise of emerging and re-emerging mosquito-borne diseases. These diseases appear to be increasing as a result of the novel juxtapositions of habitats and species that can result in new interchanges of vectors, diseases and hosts. We studied whether the mosquito community structure varied between habitats and seasons and whether known disease vectors displayed habitat preferences in tropical Australia. Using CDC model 512 traps, adult mosquitoes were sampled across an anthropogenic disturbance gradient of grassland, rainforest edge and rainforest interior habitats, in both the wet and dry seasons. Nonmetric multidimensional scaling (NMS) ordinations were applied to examine major gradients in the composition of mosquito and vector communities. We captured ~13,000 mosquitoes from 288 trap nights across four study sites. A community analysis identified 29 species from 7 genera. Even though mosquito abundance and richness were similar between the three habitats, the community composition varied significantly in response to habitat type. The mosquito community in rainforest interiors was distinctly different to the community in grasslands, whereas forest edges acted as an ecotone with shared communities from both forest interiors and grasslands. We found two community patterns that will influence disease risk at out study sites, first, that disease vectoring mosquito species occurred all year round. Secondly, that anthropogenic grasslands adjacent to rainforests may increase the probability of novel disease transmission through changes to the vector community on rainforest edges, as most disease transmitting species predominantly occurred in grasslands. Our results indicate that the strong influence of anthropogenic land use change on mosquito communities could have potential implications for pathogen transmission to humans and wildlife.

Thermal properties of composite materials : effective conductivity tensor and edge effects

NASA Astrophysics Data System (ADS)

Matine, A.; Boyard, N.; Cartraud, P.; Legrain, G.; Jarny, Y.

2012-11-01

The homogenization theory is a powerful approach to determine the effective thermal conductivity tensor of heterogeneous materials such as composites, including thermoset matrix and fibres. Once the effective properties are calculated, they can be used to solve a heat conduction problem on the composite structure at the macroscopic scale. This approach leads to good approximations of both the heat flux and temperature in the interior zone of the structure, however edge effects occur in the vicinity of the domain boundaries. In this paper, following the approach proposed in [10] for elasticity, it is shown how these edge effects can be corrected. Thus an additional asymptotic expansion is introduced, which plays the role of a edge effect term. This expansion tends to zero far from the boundary, and is assumed to decrease exponentially. Moreover, the length of the edge effect region can be determined from the solution of an eigenvalue problem. Numerical examples are considered for a standard multilayered material. The homogenized solutions computed with a finite element software, and corrected with the edge effect terms, are compared to a heterogeneous finite element solution at the microscopic scale. The influences of the thermal contrast and scale factor are illustrated for different kind of boundary conditions.

Are anharmonicity corrections needed for temperature-profile calculations of interiors of terrestrial planets

NASA Astrophysics Data System (ADS)

Anderson, O. L.

1982-07-01

The temperature profile of planetary interiors is an important item of information, because many thermodynamic or geodynamic investigations of a planet's interior require an estimate of the temperature profile. Modeling studies of the thermal history or convective processes focus in detail on the thermal profile of the planet. A description is presented of results which show how the present (or equilibrium) interior temperature profile is related to certain constraints placed on the planet, especially the physical properties of the mantle material. These properties depend upon a priori assumptions of chemical composition. The investigation is mainly concerned with experimental and theoretical data appropriate to mantle minerals, in order to justify the use of a simple equation-of-state for planet interiors. It is found that anharmonicity does not seem to be required for calculations of interior properties of the terrestrial planets.

Mitochondrial DNA variation in bull trout (Salvelinus confluentus) from northwestern North America: implications for zoogeography and conservation.

PubMed

Taylor, E B; Pollard, S; Louie, D

1999-07-01

Bull trout, Salvelinus confluentus (Salmonidae), are distributed in northwestern North America from Nevada to Yukon Territory, largely in interior drainages. The species is of conservation concern owing to declines in abundance, particularly in southern portions of its range. To investigate phylogenetic structure within bull trout that might form the basis for the delineation of major conservation units, we conducted a mitochondrial DNA (mtDNA) survey in bull trout from throughout its range. Restriction fragment length polymorphism (RFLP) analysis of four segments of the mtDNA genome with 11 restriction enzymes resolved 21 composite haplotypes that differed by an average of 0.5% in sequence. One group of haplotypes predominated in 'coastal' areas (west of the coastal mountain ranges) while another predominated in 'interior' regions (east of the coastal mountains). The two putative lineages differed by 0.8% in sequence and were also resolved by sequencing a portion of the ND1 gene in a representative of each RFLP haplotype. Significant variation existed within individual sample sites (12% of total variation) and among sites within major geographical regions (33%), but most variation (55%) was associated with differences between coastal and interior regions. We concluded that: (i) bull trout are subdivided into coastal and interior lineages; (ii) this subdivision reflects recent historical isolation in two refugia south of the Cordilleran ice sheet during the Pleistocene: the Chehalis and Columbia refugia; and (iii) most of the molecular variation resides at the interpopulation and inter-region levels. Conservation efforts, therefore, should focus on maintaining as many populations as possible across as many geographical regions as possible within both coastal and interior lineages.

The Star–Planet Connection. I. Using Stellar Composition to Observationally Constrain Planetary Mineralogy for the 10 Closest Stars

NASA Astrophysics Data System (ADS)

Hinkel, Natalie R.; Unterborn, Cayman T.

2018-01-01

The compositions of stars and planets are connected, but the definition of “habitability” and the “habitable zone” only take into account the physical relationship between the star and planet. Planets, however, are made truly habitable by both chemical and physical processes that regulate climatic and geochemical cycling between atmosphere, surface, and interior reservoirs. Despite this, an “Earth-like” planet is often defined as a planet made of a mixture of rock and Fe that is roughly 1 Earth-density. To understand the interior of a terrestrial planet, the stellar abundances of planet-building elements (e.g., Mg, Si, and Fe) can be used as a proxy for the planet’s composition. We explore the planetary mineralogy and structure for fictive planets around the 10 stars closest to the Sun using stellar abundances from the Hypatia Catalog. Although our sample contains stars that are both sub- and super-solar in their abundances, we find that the mineralogies are very similar for all 10 planets—since the error or spread in the stellar abundances create significant degeneracy in the models. We show that abundance uncertainties need to be on the order of [Fe/H] < 0.02 dex, [Si/H] < 0.01 dex, [Al/H] < 0.002 dex, while [Mg/H] and [Ca/H] < 0.001 dex in order to distinguish two unique planetary populations in our sample of 10 stars. While these precisions are high, we believe that they are possible given certain abundance techniques, in addition to methodological transparency, that have recently been demonstrated in the literature. However, without these precisions, the uncertainty in planetary structures will be so high that we will be unable to confidently state that a planet is like the Earth, or unlike anything we have ever seen. We made some cuts and ruled out a number of stars, but these 10 are still rather nearby.

Martian interior structure models with different crustal density

NASA Astrophysics Data System (ADS)

Gudkova, T. V.; Zharkov, V. N.

2007-08-01

The information necessary to construct a model of Mars (observation data, a choice of a chemical model, a cosmogonic aspect of the problem) is discussed. We consider an interior structure model which comprises four submodels - a model of the outer porous layer, a model of the crust, a model of the mantle and a model of the core. The first 10-11 km layer is considered as an averaged transition from regolith to consolidated rock. The mineral composition of the crustal basaltic rock varies with depth because of the gabbro-eclogite phase transition. Mineralogical and seismic models of the Martian crust were constructed by numerical thermodynamic simulation by Babeiko and Zharkov (2000). For the obtained from this simulation densities at the crust-mantle boundary (about 3.3-3.4 g/cm3) a density contrast between the crust and the mantle is low enough. However, the joint interpretation of gravity and topography data assumes that there is a noticeable density jump at the crust-mantle boundary. As discussed by many authors a plausible range of bulk crustal densities is from 2.7 to 3.1 g/ cm3. It can be interpreted as either the composition of rocks at the surface of Mars is somewhat different than those of the Martian basaltic meteorites or a certain amount of crustal porosity might be expected if water (or some other substances) is present in the subsurface. Assuming a range of crustal densities (2.7-3.2 g/cm3) and the average thickness of the martian crust of 50 and 100 km we have recalculated a set of interior structure models of Mars to determine this effect on the other model parameters. The models are stronly constrained by new values of Love number k2 and the mean moment of inertia have been derived by Konopliv et al. (2006). The inferred radius of Martian core (from the Love number k2) is between 1700 and 1800 km. Keeping in mind that the estimated value of the correction introduced to the Love number k2 due to the inelasticity of the interior can be both somewhat higher (~ 0.005) or slightly lower (~ 0.003) we have the inferred model radius of Martian core between 1650 and 1830 km. As the radius of the core is increasing two tendencies are seen: the density of the core is decreasing and the Fe/Si weight ratio is approaching to its chondritic value 1.7. From cosmochemical point of view, it is difficult to assume that the core contains more than 20 wt % of sulfur. The radius of such core is about 1600 km. Therefore, if the core of Mars turns out to be larger, it should contain some light admixture elements.

A comparison of the structureborne and airborne paths for propfan interior noise

NASA Technical Reports Server (NTRS)

Eversman, W.; Koval, L. R.; Ramakrishnan, J. V.

1986-01-01

A comparison is made between the relative levels of aircraft interior noise related to structureborne and airborne paths for the same propeller source. A simple, but physically meaningful, model of the structure treats the fuselage interior as a rectangular cavity with five rigid walls. The sixth wall, the fuselage sidewall, is a stiffened panel. The wing is modeled as a simple beam carried into the fuselage by a large discrete stiffener representing the carry-through structure. The fuselage interior is represented by analytically-derived acoustic cavity modes and the entire structure is represented by structural modes derived from a finite element model. The noise source for structureborne noise is the unsteady lift generation on the wing due to the rotating trailing vortex system of the propeller. The airborne noise source is the acoustic field created by a propeller model consistent with the vortex representation. Comparisons are made on the basis of interior noise over a range of propeller rotational frequencies at a fixed thrust.

Constraining Mass Anomalies Using Trans-dimensional Gravity Inversions

NASA Astrophysics Data System (ADS)

Izquierdo, K.; Montesi, L.; Lekic, V.

2016-12-01

The density structure of planetary interiors constitutes a key constraint on their composition, temperature, and dynamics. This has motivated the development of non-invasive methods to infer 3D distribution of density anomalies within a planet's interior using gravity observations made from the surface or orbit. On Earth, this information can be supplemented by seismic and electromagnetic observations, but such data are generally not available on other planets and inferences must be made from gravity observations alone. Unfortunately, inferences of density anomalies from gravity are non-unique and even the dimensionality of the problem - i.e., the number of density anomalies detectable in the planetary interior - is unknown. In this project, we use the Reversible Jump Markov chain Monte Carlo (RJMCMC) algorithm to approach gravity inversions in a trans-dimensional way, that is, considering the magnitude of the mass, the latitude, longitude, depth and number of anomalies itself as unknowns to be constrained by the observed gravity field at the surface of a planet. Our approach builds upon previous work using trans-dimensional gravity inversions in which the density contrast between the anomaly and the surrounding material is known. We validate the algorithm by analyzing a synthetic gravity field produced by a known density structure and comparing the retrieved and input density structures. We find excellent agreement between the input and retrieved structure when working in 1D and 2D domains. However, in 3D domains, comprehensive exploration of the much larger space of possible models makes search efficiency a key ingredient in successful gravity inversion. We find that upon a sufficiently long RJMCMC run, it is possible to use statistical information to recover a predicted model that matches the real model. We argue that even more complex problems, such as those involving real gravity acceleration data of a planet as the constraint, our trans-dimensional gravity inversion algorithm provides a good option to overcome the problem of non-uniqueness while achieving parsimony in gravity inversions.

A broad look at solar physics adapted from the solar physics study of August 1975

NASA Technical Reports Server (NTRS)

Parker, E.; Timothy, A.; Beckers, J.; Hundhausen, A.; Kundu, M. R.; Leith, C. E.; Lin, R.; Linsky, J.; Macdonald, F. B.; Noyes, R.

1979-01-01

The current status of our knowledge of the basic mechanisms involved in fundamental solar phenomena is reviewed. These include mechanisms responsible for heating the corona, the generation of the solar wind, the particle acceleration in flares, and the dissipation of magnetic energy in field reversal regions, known as current sheets. The discussion covers solar flares and high-energy phenomena, solar active regions; solar interior, convection, and activity; the structure and energetics of the quiet solar atmosphere; the structure of the corona; the solar composition; and solar terrestrial interactions. It also covers a program of solar research, including the special observational requirements for spectral and angular resolution, sensitivity, time resolution, and duration of the techniques employed.

Using the heterogeneity distribution in Earth's mantle to study structure and flow

NASA Astrophysics Data System (ADS)

Rost, S.; Frost, D. A.; Bentham, H. L.

2016-12-01

The Earth's interior contains heterogeneities on many scale-lengths ranging from continent sized structures such as Large-Low Shear Velocity Provinces (LLSVPs) to grain-sized anomalies resolved using geochemistry. Sources of heterogeneity in Earth's mantle are for example the recycling of crustal material through the subduction process as well as partial melting and compositional variations. The subduction and recycling of oceanic crust throughout Earth's history leads to strong heterogeneities in the mantle that can be detected using seismology and geochemistry. Current models of mantle convection show that the subducted crustal material can be long-lived and is transported passively throughout the mantle by convective flows. Settling and entrainment is dependent on the density structure of the heterogeneity. Imaging heterogeneities throughout the mantle therefore allows imaging mantle flow especially in areas of inhibited flow due to e.g. viscosity changes or changes in composition or dynamics. The short-period seismic wavefield is dominated by scattered seismic energy partly originating from scattering at small-scale heterogeneities in Earth's mantle. Using specific raypath configurations we are able to sample different depths throughout Earth's mantle for the existence and properties of heterogeneities. These scattering probes show distinct variations in energy content with frequency indicating dominant heterogeneity length-scales in the mantle. We detect changes in heterogeneity structure both in lateral and radial directions. The radial heterogeneity structure requires changes in mantle structure at depths of 1000 km and 1800 to 2000 km that could indicate a change in viscosity structure in the mid mantle partly changing the flow of subducted crustal material into the deep mantle. Lateral changes in heterogeneity structure close to the core mantle boundary indicate lateral transport inhibited by the compositional anomalies of the LLSVPs.

View northeast; interior structural detail Naval Base PhiladelphiaPhiladelphia Naval ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View northeast; interior structural detail - Naval Base Philadelphia-Philadelphia Naval Shipyard, Foundry-Propeller Shop, North of Porter Avenue, west of Third Street West, Philadelphia, Philadelphia County, PA

Optimization of ceramic strength using elastic gradients

PubMed Central

Zhang, Yu; Ma, Li

2009-01-01

We present a new concept for strengthening ceamics by utilizing a graded structure with a low elastic modulus at both top and bottom surfaces sandwiching a high-modulus interior. Closed-form equations have been developed for stress analysis of simply supported graded sandwich beams subject to transverse center loads. Theory predicts that suitable modulus gradients at the ceramic surface can effectively reduce and spread the maximum bending stress from the surface into the interior. The magnitude of such stress dissipation is governed by the thickness ratio of the beam to the graded layers. We test our concept by infiltrating both top and bottom surfaces of a strong class of zirconia ceramic with an in-house prepared glass of similar coefficient of thermal expansion and Poisson’s ratio to zirconia, producing a controlled modulus gradient at the surface without significant long-range residual stresses. The resultant graded glass/zirconia/glass composite exhibits significantly higher load-bearing capacity than homogeneous zirconia. PMID:20161019

Analysis of selected materials flown on interior locations of the Long Duration Exposure Facility

NASA Technical Reports Server (NTRS)

Smith, H. A.; Nelson, K. M.; Eash, D.; Pippin, H. G.

1994-01-01

This report documents the post-flight condition of selected hardware taken from interior locations on the Long Duration Exposure Facility (LDEF). This hardware was generally in excellent condition. Outgassing data is presented for heat shrink tubing and fiberglass composite shims. Variation in total mass loss (TML) values for heat shrink tubing were correlated with location. Nylon grommets were evaluated for mechanical integrity; slight embrittlement was observed for flight specimens. Multi-layer insulation blankets, wire bundles, and paints in non-exposed interior locations were all in visibly good condition. Silicon-containing contaminant films were observed on silver-coated hex nuts at the space- and Earth-end interior locations.

Using asteroid families to test planetesimal differentiation hypotheses

NASA Astrophysics Data System (ADS)

Jacobson, S.; Campins, H.; Delbo', M.; Michel, P.; Tanga, P.; Hanuš, J.; Morbidelli, A.

2014-07-01

There have been a series of papers (e.g., Weiss et al. 2008, 2010, 2012; Carporzen et al. 2011; Elkins-Tanton et al. 2011) suggesting that large planetesimals should have metamorphic grading within their crusts and possibly fully-differentiated interiors with mantles and cores. This is a very attractive hypothesis consistent with ideas that planetesimals form as large bodies (Johansen et al. 2007, Cuzzi et al. 2008, Morbidelli et al. 2009) and form early in Solar System history when radioactive heating is still important. It is natural to look to the asteroid belt, our prime reservoir of terrestrial planet building blocks (i.e., left-over planetesimals), for confirmation of this idea. Asteroid families, long known to be the debris from catastrophic disruptions (Hirayama 1918, Michel et al. 2003) conveniently expose the interiors of these left-overs. From simulations of the catastrophic disruption process, we know that not all material is ejected equally. Material near the surface is given higher expulsion velocities and divided into smaller pieces (Michel et al. 2004). Furthermore, while catastrophic disruptions appear to be a messy process, the largest remnants, including those formed by re-accumulation of smaller fragments, come from coherent sections of the progenitor body, although the extent and depth of these sections within the progenitor depend on its internal structure (Michel et al. 2014). This suggests that the ejected material should also maintain a coherent compositional structure (Michel et al., 2004). Therefore, compositional gradients within planetesimals should expose themselves within asteroid families. While all asteroid families share a number of common features, there is a large diversity of membership numbers, progenitor masses, collision energy, formation times, and spectroscopic type and sub-type both between and within families (Zappala et al. 1995, Nesvorny 2012). This compositional diversity allows for a thorough exploration of the consequences of the hypothesized compositional radial gradients within the planetesimal population. The circumstantial diversity (membership number, progenitor mass, and collision energy) determines how exposed the interior of the planetesimal is. Using estimates of the progenitor mass and the mass of the largest remnant (Tanga et al. 1999, Durda et al. 2007, Broz et al. 2013), we can assess the exposed nature of different asteroid families. Those with the lowest ratio of largest remnant to planetesimal mass are more exposed since more of their mass is within the asteroid family membership as opposed to being sequestered in the largest remnant. Furthermore, models of the planetesimal differentiation process are strongly size dependent since smaller bodies cool much more effectively. Therefore, progenitor mass is also a proxy for the expected degree of differentiation. Using this set of proxies, we examine a diverse array of asteroid families to test the hypothesis of differentiation or metamorphic grading.

The 3D Reference Earth Model (REM-3D): Update and Outlook

NASA Astrophysics Data System (ADS)

Lekic, V.; Moulik, P.; Romanowicz, B. A.; Dziewonski, A. M.

2016-12-01

Elastic properties of the Earth's interior (e.g. density, rigidity, compressibility, anisotropy) vary spatially due to changes in temperature, pressure, composition, and flow. In the 20th century, seismologists have constructed reference models of how these quantities vary with depth, notably the PREM model of Dziewonski and Anderson (1981). These 1D reference earth models have proven indispensable in earthquake location, imaging of interior structure, understanding material properties under extreme conditions, and as a reference in other fields, such as particle physics and astronomy. Over the past three decades, more sophisticated efforts by seismologists have yielded several generations of models of how properties vary not only with depth, but also laterally. Yet, though these three-dimensional (3D) models exhibit compelling similarities at large scales, differences in the methodology, representation of structure, and dataset upon which they are based, have prevented the creation of 3D community reference models. We propose to overcome these challenges by compiling, reconciling, and distributing a long period (>15 s) reference seismic dataset, from which we will construct a 3D seismic reference model (REM-3D) for the Earth's mantle, which will come in two flavors: a long wavelength smoothly parameterized model and a set of regional profiles. Here, we summarize progress made in the construction of the reference long period dataset, and present preliminary versions of the REM-3D in order to illustrate the two flavors of REM-3D and their relative advantages and disadvantages. As a community reference model and with fully quantified uncertainties and tradeoffs, REM-3D will facilitate Earth imaging studies, earthquake characterization, inferences on temperature and composition in the deep interior, and be of improved utility to emerging scientific endeavors, such as neutrino geoscience. In this presentation, we outline the outlook for setting up advisory community working groups and the community workshop that would assess progress, evaluate model and dataset performance, identify avenues for improvement, and recommend strategies for maximizing model adoption in and utility for the deep Earth community.

Electrical characterization of grain boundaries of CZTS thin films using conductive atomic force microscopy techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muhunthan, N.; Singh, Om Pal; Toutam, Vijaykumar, E-mail: toutamvk@nplindia.org

2015-10-15

Graphical abstract: Experimental setup for conducting AFM (C-AFM). - Highlights: • Cu{sub 2}ZnSnS{sub 4} (CZTS) thin film was grown by reactive co-sputtering. • The electronic properties were probed using conducting atomic force microscope, scanning Kelvin probe microscopy and scanning capacitance microscopy. • C-AFM current flow mainly through grain boundaries rather than grain interiors. • SKPM indicated higher potential along the GBs compared to grain interiors. • The SCM explains that charge separation takes place at the interface of grain and grain boundary. - Abstract: Electrical characterization of grain boundaries (GB) of Cu-deficient CZTS (Copper Zinc Tin Sulfide) thin films wasmore » done using atomic force microscopic (AFM) techniques like Conductive atomic force microscopy (CAFM), Kelvin probe force microscopy (KPFM) and scanning capacitance microscopy (SCM). Absorbance spectroscopy was done for optical band gap calculations and Raman, XRD and EDS for structural and compositional characterization. Hall measurements were done for estimation of carrier mobility. CAFM and KPFM measurements showed that the currents flow mainly through grain boundaries (GB) rather than grain interiors. SCM results showed that charge separation mainly occurs at the interface of grain and grain boundaries and not all along the grain boundaries.« less

Interior Studies with BepiColombo's MPO

NASA Astrophysics Data System (ADS)

Benkhoff, Johannes; Zender, Joe

2017-04-01

NASA's MESSENGER mission has fundamentally changed our view of the innermost planet. Mercury is in many ways a very different planet from what we were expecting. Now BepiColombo has to follow up on answering the fundamental questions that MESSENGER raised and go beyond. BepiColombo is a joint project between ESA and the Japanese Aerospace Exploration Agency (JAXA). The Mission consists of two orbiters, the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). The mission scenario foresees a launch of both spacecraft with an ARIANE V in October 2018 and an arrival at Mercury in 2025. From their dedicated orbits the two spacecraft will be studying the planet and its environment. The MPO scientific payload comprises eleven instruments/instrument packages; several of them dedicated to the study of the interior. Together, these instruments will perform measurements to enhance our knowledge of the planets figure and internal structure and composition. Expected results will provide further clues to the origin and evolution of a planet close to its parent star. In this presentation we will give an overview on the expected science return of BepiColombo with respect to the interior. In addition we give a brief update on the latest development status of the mission. All scientific instruments have been integrated into the spacecraft and both spacecraft are now under final acceptance testing.

Microbial Diversity in a Permanently Cold and Alkaline Environment in Greenland

PubMed Central

Glaring, Mikkel A.; Vester, Jan K.; Lylloff, Jeanette E.; Abu Al-Soud, Waleed; Sørensen, Søren J.; Stougaard, Peter

2015-01-01

The submarine ikaite columns located in the Ikka Fjord in Southern Greenland represent a unique, permanently cold (less than 6°C) and alkaline (above pH 10) environment and are home to a microbial community adapted to these extreme conditions. The bacterial and archaeal community inhabiting the ikaite columns and surrounding fjord was characterised by high-throughput pyrosequencing of 16S rRNA genes. Analysis of the ikaite community structure revealed the presence of a diverse bacterial community, both in the column interior and at the surface, and very few archaea. A clear difference in overall taxonomic composition was observed between column interior and surface. Whereas the surface, and in particular newly formed ikaite material, was primarily dominated by Cyanobacteria and phototrophic Proteobacteria, the column interior was dominated by Proteobacteria and putative anaerobic representatives of the Firmicutes and Bacteroidetes. The results suggest a stratification of the ikaite columns similar to that of classical soda lakes, with a light-exposed surface inhabited by primary producers and an anoxic subsurface. This was further supported by identification of major taxonomic groups with close relatives in soda lake environments, including members of the genera Rhodobaca, Dethiobacter, Thioalkalivibrio and Tindallia, as well as very abundant groups related to uncharacterised environmental sequences originally isolated from Mono Lake in California. PMID:25915866

Microbial diversity in a permanently cold and alkaline environment in Greenland.

PubMed

Glaring, Mikkel A; Vester, Jan K; Lylloff, Jeanette E; Al-Soud, Waleed Abu; Sørensen, Søren J; Stougaard, Peter

2015-01-01

The submarine ikaite columns located in the Ikka Fjord in Southern Greenland represent a unique, permanently cold (less than 6°C) and alkaline (above pH 10) environment and are home to a microbial community adapted to these extreme conditions. The bacterial and archaeal community inhabiting the ikaite columns and surrounding fjord was characterised by high-throughput pyrosequencing of 16S rRNA genes. Analysis of the ikaite community structure revealed the presence of a diverse bacterial community, both in the column interior and at the surface, and very few archaea. A clear difference in overall taxonomic composition was observed between column interior and surface. Whereas the surface, and in particular newly formed ikaite material, was primarily dominated by Cyanobacteria and phototrophic Proteobacteria, the column interior was dominated by Proteobacteria and putative anaerobic representatives of the Firmicutes and Bacteroidetes. The results suggest a stratification of the ikaite columns similar to that of classical soda lakes, with a light-exposed surface inhabited by primary producers and an anoxic subsurface. This was further supported by identification of major taxonomic groups with close relatives in soda lake environments, including members of the genera Rhodobaca, Dethiobacter, Thioalkalivibrio and Tindallia, as well as very abundant groups related to uncharacterised environmental sequences originally isolated from Mono Lake in California.

17. INTERIOR VIEW, LOOKING NORTHWEST, SHOWING STRUCTURAL SYSTEM, POSTS ENCASED ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. INTERIOR VIEW, LOOKING NORTHWEST, SHOWING STRUCTURAL SYSTEM, POSTS ENCASED IN CONCRETE, AND SERVICE PIT - Chesapeake Beach Railroad Engine House, 21 Yost Place, Seat Pleasant, Prince George's County, MD

Prediction of light aircraft interior noise

NASA Technical Reports Server (NTRS)

Howlett, J. T.; Morales, D. A.

1976-01-01

At the present time, predictions of aircraft interior noise depend heavily on empirical correction factors derived from previous flight measurements. However, to design for acceptable interior noise levels and to optimize acoustic treatments, analytical techniques which do not depend on empirical data are needed. This paper describes a computerized interior noise prediction method for light aircraft. An existing analytical program (developed for commercial jets by Cockburn and Jolly in 1968) forms the basis of some modal analysis work which is described. The accuracy of this modal analysis technique for predicting low-frequency coupled acoustic-structural natural frequencies is discussed along with trends indicating the effects of varying parameters such as fuselage length and diameter, structural stiffness, and interior acoustic absorption.

The 3D Reference Earth Model: Status and Preliminary Results

NASA Astrophysics Data System (ADS)

Moulik, P.; Lekic, V.; Romanowicz, B. A.

2017-12-01

In the 20th century, seismologists constructed models of how average physical properties (e.g. density, rigidity, compressibility, anisotropy) vary with depth in the Earth's interior. These one-dimensional (1D) reference Earth models (e.g. PREM) have proven indispensable in earthquake location, imaging of interior structure, understanding material properties under extreme conditions, and as a reference in other fields, such as particle physics and astronomy. Over the past three decades, new datasets motivated more sophisticated efforts that yielded models of how properties vary both laterally and with depth in the Earth's interior. Though these three-dimensional (3D) models exhibit compelling similarities at large scales, differences in the methodology, representation of structure, and dataset upon which they are based, have prevented the creation of 3D community reference models. As part of the REM-3D project, we are compiling and reconciling reference seismic datasets of body wave travel-time measurements, fundamental mode and overtone surface wave dispersion measurements, and normal mode frequencies and splitting functions. These reference datasets are being inverted for a long-wavelength, 3D reference Earth model that describes the robust long-wavelength features of mantle heterogeneity. As a community reference model with fully quantified uncertainties and tradeoffs and an associated publically available dataset, REM-3D will facilitate Earth imaging studies, earthquake characterization, inferences on temperature and composition in the deep interior, and be of improved utility to emerging scientific endeavors, such as neutrino geoscience. Here, we summarize progress made in the construction of the reference long period dataset and present a preliminary version of REM-3D in the upper-mantle. In order to determine the level of detail warranted for inclusion in REM-3D, we analyze the spectrum of discrepancies between models inverted with different subsets of the reference dataset. This procedure allows us to evaluate the extent of consistency in imaging heterogeneity at various depths and between spatial scales.

Crystal structure and equation of state of Fe-Si alloys at super-Earth core conditions

PubMed Central

Fratanduono, Dayne E.; Coppari, Federica; Newman, Matthew G.; Duffy, Thomas S.

2018-01-01

The high-pressure behavior of Fe alloys governs the interior structure and dynamics of super-Earths, rocky extrasolar planets that could be as much as 10 times more massive than Earth. In experiments reaching up to 1300 GPa, we combine laser-driven dynamic ramp compression with in situ x-ray diffraction to study the effect of composition on the crystal structure and density of Fe-Si alloys, a potential constituent of super-Earth cores. We find that Fe-Si alloy with 7 weight % (wt %) Si adopts the hexagonal close-packed structure over the measured pressure range, whereas Fe-15wt%Si is observed in a body-centered cubic structure. This study represents the first experimental determination of the density and crystal structure of Fe-Si alloys at pressures corresponding to the center of a ~3–Earth mass terrestrial planet. Our results allow for direct determination of the effects of light elements on core radius, density, and pressures for these planets. PMID:29707632

Crystal structure and equation of state of Fe-Si alloys at super-Earth core conditions

DOE PAGES

Wicks, June K.; Smith, Raymond F.; Fratanduono, Dayne E.; ...

2018-04-25

In this paper, the high-pressure behavior of Fe alloys governs the interior structure and dynamics of super-Earths, rocky extrasolar planets that could be as much as ten times more massive than Earth. In experiments reaching up to 1300 GPa, we combine laser-driven dynamic ramp compression with in situ X-ray diffraction to study the effect of composition on the crystal structure and density of Fe-Si alloys, a potential constituent of super-Earth cores. We find that Fe-7wt.%Si adopts the hexagonal close packed (hcp) structure over the measured pressure range, whereas Fe-15wt.%Si is observed in a body-centered cubic (bcc) structure. This study representsmore » the first experimental determination of the density and crystal structure of Fe-Si alloys at pressures corresponding to the center of a ~3 Earth-mass terrestrial planet. Our results allow for direct determination of the effects of light elements on core radius, density, and pressures for such planets.« less

Crystal structure and equation of state of Fe-Si alloys at super-Earth core conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wicks, June K.; Smith, Raymond F.; Fratanduono, Dayne E.

In this paper, the high-pressure behavior of Fe alloys governs the interior structure and dynamics of super-Earths, rocky extrasolar planets that could be as much as ten times more massive than Earth. In experiments reaching up to 1300 GPa, we combine laser-driven dynamic ramp compression with in situ X-ray diffraction to study the effect of composition on the crystal structure and density of Fe-Si alloys, a potential constituent of super-Earth cores. We find that Fe-7wt.%Si adopts the hexagonal close packed (hcp) structure over the measured pressure range, whereas Fe-15wt.%Si is observed in a body-centered cubic (bcc) structure. This study representsmore » the first experimental determination of the density and crystal structure of Fe-Si alloys at pressures corresponding to the center of a ~3 Earth-mass terrestrial planet. Our results allow for direct determination of the effects of light elements on core radius, density, and pressures for such planets.« less

Interior view of living area and living porch showing structural ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior view of living area and living porch showing structural system, facing north. - Albrook Air Force Station, Company Officer's Quarters, East side of Canfield Avenue, Balboa, Former Panama Canal Zone, CZ

INTERIOR OF ROOF STRUCTURE LOOKING FROM TOP OF PROJECTION BOOTH, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR OF ROOF STRUCTURE LOOKING FROM TOP OF PROJECTION BOOTH, VIEW FACING SOUTH-SOUTHWEST. - Naval Air Station Barbers Point, Theater, Yorktown Avenue between Wasp & Saipan Streets, Ewa, Honolulu County, HI

A key for predicting postfire successional trajectories in black spruce stands of interior Alaska.

Treesearch

Jill F. Johnstone; Teresa N. Hollingsworth; F. Stuart Chapin

2008-01-01

Black spruce (Picea mariana (Mill) B.S.P) is the dominant forest cover type in interior Alaska and is prone to frequent, stand-replacing wildfires. Through impacts on tree recruitment, the degree of fire consumption of soil organic layers can act as an important determinant of whether black spruce forests regenerate to a forest composition similar...

Compositional evidence regarding the origins of rims on Semarkona chondrules

USGS Publications Warehouse

Grossman, J.N.; Wasson, J.T.

1987-01-01

The compositions of the interiors and abraded surfaces of 7 chondrules from Semarkona (LL3.0) were measured by neutron activation analysis. For nonvolatile elements, the lithophile and siderophile element abundance patterns in the surfaces are generally similar to those in the corresponding interiors. Siderophile and chalcophile concentrations are much higher in the surfaces, whereas lithophile concentrations are similar in both fractions. Most of the similarities in lithophile patterns and some of the similarities in siderophile patterns between surfaces and interiors may reflect incomplete separation of the fractions in the laboratory, but for 3 or 4 chondrules the siderophile resemblance is inherent, implying that the surface and interior metal formed from a single precursor assemblage. Metal and sulfide-rich chondrule rims probably formed when droplets of these phases that migrated to the chondrule surface during melting were reheated and incorporated into matrix-like material that had accreted onto the surface. The moderately-volatile to volatile elements K, As and Zn tend to be enriched in the surfaces compared with other elements of similar mineral affinity; both enrichments and depletions are observed for other moderately volatile elements. A small fraction of chondrules experienced fractional evaporation while they were molten. ?? 1987.

Alteration Of Nutrient Status By Manipulation Of Composition And Density In A Shortleaf Pine-Hardwood Stand

Treesearch

Hal O. Liechty; Valerie L. Sawyer; Michael G. Shelton

2002-01-01

Abstract - Uneven-aged management is used to promote adequate pine reproduction and control species composition of shortleaf pine (Pinus echinata Mill.)-hardwood stands in the Interior Highlands of the southern United States. The modification of pine-hardwood composition in these stands has the potential to alter nutrient pools and availability since...

Engine-induced structural-borne noise in a general aviation aircraft

NASA Technical Reports Server (NTRS)

Unruh, J. F.; Scheidt, D. C.; Pomerening, D. J.

1979-01-01

Structural borne interior noise in a single engine general aviation aircraft was studied to determine the importance of engine induced structural borne noise and to determine the necessary modeling requirements for the prediction of structural borne interior noise. Engine attached/detached ground test data show that engine induced structural borne noise is a primary interior noise source for the single engine test aircraft, cabin noise is highly influenced by responses at the propeller tone, and cabin acoustic resonances can influence overall noise levels. Results from structural and acoustic finite element coupled models of the test aircraft show that wall flexibility has a strong influence on fundamental cabin acoustic resonances, the lightweight fuselage structure has a high modal density, and finite element analysis procedures are appropriate for the prediction of structural borne noise.

Seismology of Giant Planets: General Overview and Results from the Kepler K2 Observations of Neptune

NASA Astrophysics Data System (ADS)

Gaulme, Patrick

2017-10-01

For this invited contribution, I was asked to give an overview about the application of helio and aster-oseismic techniques to study the interior of giant planets, and to specifically present the recent observations of Neptune by Kepler K2. Seismology applied to giant planets could drastically change our understanding of their deep interiors, as it has happened with the Earth, the Sun, and many main-sequence and evolved stars. The study of giant planets' composition is important for understanding both the mechanisms enabling their formation and the origins of planetary systems, in particular our own. Unfortunately, its determination is complicated by the fact that their interior is thought not to be homogeneous, so that spectroscopic determinations of atmospheric abundances are probably not representative of the planet as a whole. Instead, the determination of their composition and structure must rely on indirect measurements and interior models. Giant planets are mostly fluid and convective, which makes their seismology much closer to that of solar-like stars than that of terrestrial planets. Hence, helioseismology techniques naturally transfer to giant planets. In addition, two alternative methods can be used: photometry of the solar light reflected by planetary atmospheres, and ring seismology in the specific case of Saturn. The current decade has been promising thanks to the detection of Jupiter's acoustic oscillations with the ground-based imaging-spectrometer SYMPA and indirect detection of Saturn's f-modes in its rings by the NASA Cassini orbiter. This has motivated new projects of ground-based and space-borne instruments that are under development. The K2 observations represented the first opportunity to search for planetary oscillations with visible photometry. Despite the excellent quality of K2 data, the noise level of the power spectrum of the light curve was not low enough to detect Neptune's oscillations. The main results from the K2 observations are the clear detection of the well-known differential rotation of Neptune, measured for the first time through the rotational modulation of its photometry, and the detection of the Sun's oscillations, for the first time in an indirect way in intensity measurements.

Rocky or Not, Here We Come: Further Revealing the Internal Structures of K2-21b+c Through Transit Timing

NASA Astrophysics Data System (ADS)

Stevenson, Kevin; Bean, Jacob; Dragomir, Diana; Fabrycky, Daniel; Kreidberg, Laura; Mills, Sean; Petigura, Erik

2016-08-01

The provenance of planets 1.5 - 2 times the size of the Earth is one of the biggest unresolved mysteries from the Kepler mission. Determining the nature and origins of these exoplanets relies not only on measuring their radii, but also requires knowledge about their masses, atmospheric compositions, and interior structures. With this information, we can more confidently estimate planet mass distributions from measured radii, distinguish between rocky and non-rocky compositions, and better constrain the occurrence rate of Earth-like planets. Last year, Co-I Petigura announced the discovery of a two-transiting-planet system, K2-21, with bodies of 1.6 and 1.9 Earth-radii. The latter is expected to have a volatile-rich atmosphere, but the former lies squarely on the rocky/non-rocky composition boundary. These exoplanets orbit their relatively bright, nearby M dwarf parent star in a near 5:3 resonance and, based on our successful Spitzer observations, exhibit measurable transit timing variations (TTVs). Complete knowledge about their interactions will reveal constraints on the planets' masses, which is important because significant stellar activity makes RV mass measurements impractical. We propose to continue measuring precise transit times of K2-21b and K2-21c with Spitzer and combine that information with existing K2 timing constraints to determine their masses. Understanding the planets' masses is a critical, first step to ultimately determining their atmospheric compositions and internal structures. These planets will provide an excellent test to current statistical arguments that suggest there is a turning point in composition from rocky, true-to-name super-Earths to volatile-rich sub-Neptunes in the range of 1.5 - 2 Earth-radii.

Understanding divergent evolution of Earth-like planets: The case for a Venus exploration program

NASA Astrophysics Data System (ADS)

Crisp, D.

The planet Venus is our most Earth-like neighbor in size, mass, and solar distance. In spite of these similarities, the Venus surface and atmosphere are characterized by some of the most enigmatic features seen anywhere in the solar system. Here, we propose a Venus exploration program designed to explain the origin and divergent evolution of the interiors, surfaces, and atmospheres of the terrestrial planets in our solar system, and provide greater insight into the conditions that may affect the habitability of terrestrial planets in other solar systems. This program includes: - The Noble Gas and Trace Gas Explorer is the highest priority mission because itsdata are vital to our understanding of the origin of Venus. This Discovery classmission requires a single entry probe that will carry the state-of-the-art instrumentsneeded to complete the noble gas and trace gas inventories between the cloud topsand the surface. - The Global Geological Process Mapping Orbiter is a Discovery class mission. Itwill carry a C- and/or X-band radar designed for stereo or interferometric imaging,to provide global maps of the surface at horizontal resolutions of 25 to 50 metersto identify and characterize the geologic processes that have shaped the Venussurface. - The Atmospheric Composition Orbiter is a Discovery class mission that will carryremote sensing instruments for characterizing clouds and trace gas variationsthroughout the atmosphere. This mission will collect the data needed tocharacterize the radiative, chemical, and dynamical processes that are maintainingthe thermal structure and composition of the present atmosphere. - The Atmospheric Dynamics Explorer is a New Frontiers class mission that willdeploy 12 to 24 long-lived balloons over a range of latitudes and altitudes toidentify the mechanisms responsible for maintaining the atmosphericsuperrotation. - The Surface and Interior Explorer is a New Frontiers class mission that will deploythree or more long-lived landers on the Venus surface. Each lander will carry aseismometer for studies of the interior structure, as well as in situ instruments forcharacterizing the surface mineralogy and elemental composition. This missionrequires significant technology development. - A Sample Return mission will eventually be needed to conduct investigations ofthe Venus surface and atmosphere that cannot be conducted by instruments onremote sensing platforms or on entry probes. This will probably require a largemission and significant technology development. This series of missions will complement and expand on the science objectives of the proposed ESA Venus Express Mission and the ISAS Venus Climate Orbiter.

Effect of rotation on fingering convection in stellar and planetary interiors

NASA Astrophysics Data System (ADS)

Sengupta, Sutirtha; Garaud, Pascale

2018-01-01

We study the effects of global rotation on the growth and saturation of the fingering (double-diffusive) instability at low Prandtl numbers and estimate the compositional transport rates as a function of the relevant non-dimensional parameters - the Taylor number, Ta^* (defined in terms of the rotation rate, Ω, thermal diffusivity κ_T and associated finger length scale d) and density ratio through direct numerical simulations. Within our explored range of parameters, we find rotation to have very little effect on vertical transport apart for an exceptional case where a cyclonic large scale vortex (LSV) is observed at low density ratio and fairly high Taylor number. The LSV leads to significant enhancement in the fingering transport rates by concentrating high composition fluid at its core which moves downward. The formation of such LSVs is of particular interest for solving the missing mixing problem in the astrophysical context of RGB stars though the parameter regime in which we observe the emergence of this LSV seems to be quite far from the stellar scenario. However, understanding the basic mechanism driving such large scale structures as observed frequently in polar regions of planets (e.g. those seen by Juno near the poles of Jupiter) is important in general for studies of rotating turbulence and its applications to stellar and planetary interior studies, and will be investigated in further detail in a forthcoming work.

Ablation properties of inorganic filler modified benzoxazine composite coating irradiated by high-intensity continuous laser

NASA Astrophysics Data System (ADS)

Xu, Feng; Ma, Zhuang; Li, Hezhang; Gao, Lihong; Wang, Fuchi

2017-05-01

Benzoxazine resin with good heat resistance, low combustion heat release and high char yield is a promising thermosetting resin. Meanwhile, research shows that the inorganic filler can effectively improve the thermodynamic property of the resin. It makes that the inorganic filler modified benzoxazine may have a potential application in laser ablation. The benzoxazine coating with and without inorganic filler ammonium polyphosphate, melamine and pentaerythritol (P-BOZ and BOZ) were prepared by brush and thermal curing method. The ablation properties of these coatings irradiated by high-intensity laser were investigated. The scanning electron microscope, Raman spectroscopy and thermal gravimetric analysis were used to characterize the micrographs, carbon layer structure and thermodynamic property of the sample. Results show that the composite coating has excellent thermal protective properties. The back temperature of 20 wt% P-BOZ coating under different parameter laser power (1000W/cm2, 5s; 1000W/cm2, 10s) are 40% lower than these of the BOZ coating and the 20 wt% P-BOZ has higher mass ablation rate. In the surface layer of the irradiated area, dense carbon layer is produced which reduces the absorb of the laser energy of the interior. In the interior of the sample, a large number of closed bell shaped holes are generated which are beneficial to obstruct the heat conduction.

The vibro-acoustic response and analysis of a full-scale aircraft fuselage section for interior noise reduction.

PubMed

Herdic, Peter C; Houston, Brian H; Marcus, Martin H; Williams, Earl G; Baz, Amr M

2005-06-01

The surface and interior response of a Cessna Citation fuselage section under three different forcing functions (10-1000 Hz) is evaluated through spatially dense scanning measurements. Spatial Fourier analysis reveals that a point force applied to the stiffener grid provides a rich wavenumber response over a broad frequency range. The surface motion data show global structural modes (approximately < 150 Hz), superposition of global and local intrapanel responses (approximately 150-450 Hz), and intrapanel motion alone (approximately > 450 Hz). Some evidence of Bloch wave motion is observed, revealing classical stop/pass bands associated with stiffener periodicity. The interior response (approximately < 150 Hz) is dominated by global structural modes that force the interior cavity. Local intrapanel responses (approximately > 150 Hz) of the fuselage provide a broadband volume velocity source that strongly excites a high density of interior modes. Mode coupling between the structural response and the interior modes appears to be negligible due to a lack of frequency proximity and mismatches in the spatial distribution. A high degree-of-freedom finite element model of the fuselage section was developed as a predictive tool. The calculated response is in good agreement with the experimental result, yielding a general model development methodology for accurate prediction of structures with moderate to high complexity.

Evaluation of Materials and Concepts for Aircraft Fire Protection

NASA Technical Reports Server (NTRS)

Anderson, R. A.; Price, J. O.; Mcclure, A. H.; Tustin, E. A.

1976-01-01

Woven fiberglass fluted-core simulated aircraft interior panels were flame tested and structurally evaluated against the Boeing 747 present baseline interior panels. The NASA-defined panels, though inferior on a strength-to-weight basis, showed better structural integrity after flame testing, due to the woven fiberglass structure.

Water, High-altitude Condensates, and Possible Methane Depletion in the Atmosphere of the Warm Super-Neptune WASP-107b

NASA Astrophysics Data System (ADS)

Kreidberg, Laura; Line, Michael R.; Thorngren, Daniel; Morley, Caroline V.; Stevenson, Kevin B.

2018-05-01

The super-Neptune exoplanet WASP-107b is an exciting target for atmosphere characterization. It has an unusually large atmospheric scale height and a small, bright host star, raising the possibility of precise constraints on its current nature and formation history. We report the first atmospheric study of WASP-107b, a Hubble Space Telescope (HST) measurement of its near-infrared transmission spectrum. We determined the planet’s composition with two techniques: atmospheric retrieval based on the transmission spectrum and interior structure modeling based on the observed mass and radius. The interior structure models set a 3σ upper limit on the atmospheric metallicity of 30× solar. The transmission spectrum shows strong evidence for water absorption (6.5σ confidence), and the retrieved water abundance is consistent with expectations for a solar abundance pattern. The inferred carbon-to-oxygen ratio is subsolar at 2.7σ confidence, which we attribute to possible methane depletion in the atmosphere. The spectral features are smaller than predicted for a cloud-free composition, crossing less than one scale height. A thick condensate layer at high altitudes (0.1–3 mbar) is needed to match the observations. We find that physically motivated cloud models with moderate sedimentation efficiency (f sed = 0.3) or hazes with a particle size of 0.3 μm reproduce the observed spectral feature amplitude. Taken together, these findings serve as an illustration of the diversity and complexity of exoplanet atmospheres. The community can look forward to more such results with the high precision and wide spectral coverage afforded by future observing facilities.

Un-Earth-like interiors of the Earth-like planets

NASA Astrophysics Data System (ADS)

Shim, S. H. D.; Nisr, C.; Pagano, M.; Chen, H.; Ko, B.; Noble, S.; Leinenweber, K. D.; Young, P.; Desch, S. J.

2015-12-01

A number of exoplanets have been described as "Earth-like" planets (or even exo-earths) based on the mass-radius relations. Yet, significant variations have been documented in elemental abundances of planet-hosting stars, which will result in very different structures and processes in the interiors of rocky exoplanets. Recent data suggest that the Mg/Si ratio can be as small as less than 1 and as large as more than 2, opening the possibilities for the upper mantles to be dominated by pyroxene and olivine, respectively, and the lower mantles to be dominated by bridgmanite and ferropericlase, respectively. The changes in mineralogy will alter key properties, such as discontinuity structures (and therefore scale of mantle mixing), viscosity, and volatiles storage, of the mantle. Partial melting of such mantles would result in different compositions of the crusts, affecting the tectonics. However, the prediction should be made carefully because oxygen fugacity and contents of volatiles can change the mineralogy even for the same bulk composition. In extremely reducing proto-planetary disks, carbides will form instead of oxides and silicates, and become main constituents of planets in the system. Because carbides have high thermal conductivity and low thermal expansivity, internal heat transport of such planets may be dominated by conduction and mantle mixing would be much more limited than that of the Earth. However, the behaviors and properties of carbides need to be understood better at high pressure and high temperature. Some rocky exoplanets may have very thick layers of water and other icy materials. Interactions between ice (or fluid) and rock at extreme conditions would be the key to understand dynamics and habitability of such exoplanets.

Biodegradable/Compostable Composites From Ligno-Cellulosic Fibers

USDA-ARS?s Scientific Manuscript database

The increased importance of renewable resources for raw materials and recyclabi1ity/biodegradability of the product at the end of the useful life are demanding a shift from petroleum-based synthetics to agro-based natural fibers in automotive interiors. Natural fiber composites can contribute greatl...

Composites

NASA Astrophysics Data System (ADS)

Taylor, John G.

The Composites market is arguably the most challenging and profitable market for phenolic resins aside from electronics. The variety of products and processes encountered creates the challenges, and the demand for high performance in critical operations brings value. Phenolic composite materials are rendered into a wide range of components to supply a diverse and fragmented commercial base that includes customers in aerospace (Space Shuttle), aircraft (interiors and brakes), mass transit (interiors), defense (blast protection), marine, mine ducting, off-shore (ducts and grating) and infrastructure (architectural) to name a few. For example, phenolic resin is a critical adhesive in the manufacture of honeycomb sandwich panels. Various solvent and water based resins are described along with resin characteristics and the role of metal ions for enhanced thermal stability of the resin used to coat the honeycomb. Featured new developments include pultrusion of phenolic grating, success in RTM/VARTM fabricated parts, new ballistic developments for military vehicles and high char yield carbon-carbon composites along with many others. Additionally, global regional market resin volumes and sales are presented and compared with other thermosetting resin systems.

View south; interior structural detail at column A13 south bay ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View south; interior structural detail at column A13 south bay - Naval Base Philadelphia-Philadelphia Naval Shipyard, Foundry-Propeller Shop, North of Porter Avenue, west of Third Street West, Philadelphia, Philadelphia County, PA

Two radars for AIM mission: A direct observation of the asteroid's structure from deep interior to regolith

NASA Astrophysics Data System (ADS)

Herique, A.; Ciarletti, V.

2015-10-01

Our knowledge of the internal structure of asteroids is, so far, indirect - relying entirely on inferences from remote sensing observations of the surface, and theoretical modeling. What are the bulk properties of the regolith and deep interior? And what are the physical processes that shape their internal structures? Direct measurements are needed to provide answers that will directly improve our ability to understand and model the mechanisms driving Near Earth Asteroids (NEA) for the benefit of science as well as for planetary defense or exploration. Radar tomography is the only technique to characterize internal structure from decimetric scale to global scale. This paper reviews the benefits of direct measurement of the asteroid interior. Then the radar concepts for both deep interior and shallow subsurface are presented and the radar payload proposed for the AIDA/AIM mission is outlined.

Exploring the Largest Mass Fraction of the Solar System: the Case for Planetary Interiors

NASA Technical Reports Server (NTRS)

Danielson, L. R.; Draper, D.; Righter, K.; McCubbin, F.; Boyce, J.

2017-01-01

Why explore planetary interiors: The typical image that comes to mind for planetary science is that of a planet surface. And while surface data drive our exploration of evolved geologic processes, it is the interiors of planets that hold the key to planetary origins via accretionary and early differentiation processes. It is that initial setting of the bulk planet composition that sets the stage for all geologic processes that follow. But nearly all of the mass of planets is inaccessible to direct examination, making experimentation an absolute necessity for full planetary exploration.

Synthesis, structural and optical properties of ZnO spindle/reduced graphene oxide composites with enhanced photocatalytic activity under visible light irradiation

NASA Astrophysics Data System (ADS)

Prabhu, S.; Pudukudy, M.; Sohila, S.; Harish, S.; Navaneethan, M.; Navaneethan, D.; Ramesh, R.; Hayakawa, Y.

2018-05-01

In the present work, spindle-shaped ZnO and reduced graphene oxide sheets were successfully synthesized by a hydrothermal method and then ZnO/r-GO composite was prepared by a direct solution mixing method. Various characterization results confirmed the interior and surface decoration of spindle-shaped ZnO on the reduced graphene oxide sheets. The phase formation, crystalline structure, morphology, surface states and optical properties were characterized using Powder X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR) and UV-Vis spectroscopy. The X-ray diffraction analysis showed the formation of the hexagonal wurtzite crystalline structure of ZnO with high crystalline quality. The band gap of the ZnO/r-GO composite was found to be low (3.03eV) compared to the band gap of spindle shaped ZnO (3.13 eV), as calculated from optical studies. The spindle-like morphology of the single crystalline ZnO was clearly shown in the electron microscopic images. The chemical bonding and surface states of the samples were studied using XPS measurement. Moreover, a possible growth mechanism for the ZnO spindle was proposed. The catalytic activity of the as-synthesized samples was evaluated for the photodegradation of methylene blue under visible light irradiation. Among the synthesized samples, the ZnO/r-GO composite showed higher degradation efficiency of 93% and successfully reused for four consecutive run without any activity loss.

Apply 3D model on the customized product color combination for the interior decoration

NASA Astrophysics Data System (ADS)

Chen, Cheih-Ying

2013-03-01

The customized product color interface for the interior decoration is designed to simulate the display of various color combination sofas in the interior of the room. There are 144 color combinations of the spatial image resulted from four the interior rooms and 36 popular color sofas. The image compositing technique is adopted to appear the 144 color combinations of the spatial image on computer screen. This study tests the experience of using the interface by the questionnaire for User Interface Satisfaction (QUIS). The results show that the high grade of evaluation items including wonderful, easy, satisfying, stimulating and flexible for the experience of users. Therefore, the entrepreneur who wants to display the color primarily commodity could using the customized color combination interface with 3D models for consumers to take opportunity to find the appropriate products to meet with the interior room, so as to shorten communication time between entrepreneurs and consumers.

14. INTERIOR OF ROOM 101 LOOKING NORTHWEST. SIX OVER SIX ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. INTERIOR OF ROOM 101 LOOKING NORTHWEST. SIX OVER SIX LITE WOOD FRAME WINDOWS ARE CENTERED ON NORTHEAST AND NORTHWEST WALLS. ADDED TREATMENT TO WALLS IS A GYPSUM BOARD FINISH WITH WOOD TRIM, BOTH PAINTED. ADDED FLOOR TREATMENT IS VINYL COMPOSITION TILE. - Presidio of San Francisco, Cavalry Stables, Cowles Street, between Lincoln Boulevard & McDowell Street, San Francisco, San Francisco County, CA

Coir fiber reinforced polypropylene composite panel for automotive interior applications

Treesearch

Nadir Ayrilmis; Songklod Jarusombuti; Vallayuth Fueangvivat; Piyawade Bauchongkol; Robert H. White

2011-01-01

In this study, physical, mechanical, and flammability properties of coconut fiber reinforced polypropylene (PP) composite panels were evaluated. Four levels of the coir fiber content (40, 50, 60, and 70 % based on the composition by weight) were mixed with the PP powder and a coupling agent, 3 wt % maleic anhydride grafted PP (MAPP) powder. The water resistance and the...

A suppression of differential rotation in Jupiter’s deep interior

NASA Astrophysics Data System (ADS)

Guillot, T.; Miguel, Y.; Militzer, B.; Hubbard, W. B.; Kaspi, Y.; Galanti, E.; Cao, H.; Helled, R.; Wahl, S. M.; Iess, L.; Folkner, W. M.; Stevenson, D. J.; Lunine, J. I.; Reese, D. R.; Biekman, A.; Parisi, M.; Durante, D.; Connerney, J. E. P.; Levin, S. M.; Bolton, S. J.

2018-03-01

Jupiter’s atmosphere is rotating differentially, with zones and belts rotating at speeds that differ by up to 100 metres per second. Whether this is also true of the gas giant’s interior has been unknown, limiting our ability to probe the structure and composition of the planet. The discovery by the Juno spacecraft that Jupiter’s gravity field is north–south asymmetric and the determination of its non-zero odd gravitational harmonics J3, J5, J7 and J9 demonstrates that the observed zonal cloud flow must persist to a depth of about 3,000 kilometres from the cloud tops. Here we report an analysis of Jupiter’s even gravitational harmonics J4, J6, J8 and J10 as observed by Juno and compared to the predictions of interior models. We find that the deep interior of the planet rotates nearly as a rigid body, with differential rotation decreasing by at least an order of magnitude compared to the atmosphere. Moreover, we find that the atmospheric zonal flow extends to more than 2,000 kilometres and to less than 3,500 kilometres, making it fully consistent with the constraints obtained independently from the odd gravitational harmonics. This depth corresponds to the point at which the electric conductivity becomes large and magnetic drag should suppress differential rotation. Given that electric conductivity is dependent on planetary mass, we expect the outer, differentially rotating region to be at least three times deeper in Saturn and to be shallower in massive giant planets and brown dwarfs.

Global Electromagnetic Imaging of Lithosphere and Upper Mantle from Space and Ground. Recent Results and Challenges

NASA Astrophysics Data System (ADS)

Kuvshinov, A. V.

2016-12-01

Electrical conductivity is one of the characteristic physical parameters of materials making up Earth's interior which is sensitive to variations of temperature, chemical composition, water content, and partial melt. As a consequence, estimating lithosphere and upper mantle (LUM) electrical conductivity structure is a potentially strong tool for mapping their chemistry, mineralogy and physical structure thus presenting a complementary method to seismic studies that focus on LUM elastic properties. Global electromagnetic (EM) studies, which provide information on LUM electrical conductivity, have attracted increasing interest during the last decade, mainly for three reasons. A primary reason is the recent growth in the amount of EM data available, especially from low-Earth orbiting magnetic satellite missions (Oersted, CHAMP, SAC-C, and Swarm). A second reason is the great interest in the characterization of the three-dimensional properties of Earth's interior on a global scale. Finally, the interest has also resulted from the significant methodological progress made during the last years in EM data analysis, forward modelling and inversion. In this talk I will summarize advances and challenges in EM data interpretation, and present recent global and regional models of LUM conductivity derived from satellite and ground-based data. I will also discuss possible topics for future research.

Stabilization of ammonia-rich hydrate inside icy planets.

PubMed

Naden Robinson, Victor; Wang, Yanchao; Ma, Yanming; Hermann, Andreas

2017-08-22

The interior structure of the giant ice planets Uranus and Neptune, but also of newly discovered exoplanets, is loosely constrained, because limited observational data can be satisfied with various interior models. Although it is known that their mantles comprise large amounts of water, ammonia, and methane ices, it is unclear how these organize themselves within the planets-as homogeneous mixtures, with continuous concentration gradients, or as well-separated layers of specific composition. While individual ices have been studied in great detail under pressure, the properties of their mixtures are much less explored. We show here, using first-principles calculations, that the 2:1 ammonia hydrate, (H 2 O)(NH 3 ) 2 , is stabilized at icy planet mantle conditions due to a remarkable structural evolution. Above 65 GPa, we predict it will transform from a hydrogen-bonded molecular solid into a fully ionic phase O 2- ([Formula: see text]) 2 , where all water molecules are completely deprotonated, an unexpected bonding phenomenon not seen before. Ammonia hemihydrate is stable in a sequence of ionic phases up to 500 GPa, pressures found deep within Neptune-like planets, and thus at higher pressures than any other ammonia-water mixture. This suggests it precipitates out of any ammonia-water mixture at sufficiently high pressures and thus forms an important component of icy planets.

Micelle-template synthesis of hollow silica spheres for improving water vapor permeability of waterborne polyurethane membrane

PubMed Central

Bao, Yan; Wang, Tong; Kang, Qiaoling; Shi, Chunhua; Ma, Jianzhong

2017-01-01

Hollow silica spheres (HSS) with special interior spaces, high specific surface area and excellent adsorption and permeability performance were synthesized via micelle-template method using cetyl trimethyl ammonium bromide (CTAB) micelles as soft template and tetraethoxysilane (TEOS) as silica precursor. SEM, TEM, FT-IR, XRD, DLS and BET-BJH were carried out to characterize the morphology and structure of as-obtained samples. The results demonstrated that the samples were amorphous with a hollow structure and huge specific surface area. The growth of HSS was an inward-growth mechanism along template. Notably, we have provided a new and interesting fundamental principle for HSS materials by precisely controlling the ethanol-to-water volume ratio. In addition, the as-obtained HSS were mixed with waterborne polyurethane (WPU) to prepare WPU/HSS composite membrane. Various characterizations (SEM, TEM, FT-IR and TGA) revealed the morphology, polydispersity and adherence between HSS and WPU. Performance tests showed that the introduction of HSS can improve the water vapor permeability of composite membrane, promoting its water resistance and mechanical performance at the same time. PMID:28429740

Micelle-template synthesis of hollow silica spheres for improving water vapor permeability of waterborne polyurethane membrane

NASA Astrophysics Data System (ADS)

Bao, Yan; Wang, Tong; Kang, Qiaoling; Shi, Chunhua; Ma, Jianzhong

2017-04-01

Hollow silica spheres (HSS) with special interior spaces, high specific surface area and excellent adsorption and permeability performance were synthesized via micelle-template method using cetyl trimethyl ammonium bromide (CTAB) micelles as soft template and tetraethoxysilane (TEOS) as silica precursor. SEM, TEM, FT-IR, XRD, DLS and BET-BJH were carried out to characterize the morphology and structure of as-obtained samples. The results demonstrated that the samples were amorphous with a hollow structure and huge specific surface area. The growth of HSS was an inward-growth mechanism along template. Notably, we have provided a new and interesting fundamental principle for HSS materials by precisely controlling the ethanol-to-water volume ratio. In addition, the as-obtained HSS were mixed with waterborne polyurethane (WPU) to prepare WPU/HSS composite membrane. Various characterizations (SEM, TEM, FT-IR and TGA) revealed the morphology, polydispersity and adherence between HSS and WPU. Performance tests showed that the introduction of HSS can improve the water vapor permeability of composite membrane, promoting its water resistance and mechanical performance at the same time.

Micelle-template synthesis of hollow silica spheres for improving water vapor permeability of waterborne polyurethane membrane.

PubMed

Bao, Yan; Wang, Tong; Kang, Qiaoling; Shi, Chunhua; Ma, Jianzhong

2017-04-21

Hollow silica spheres (HSS) with special interior spaces, high specific surface area and excellent adsorption and permeability performance were synthesized via micelle-template method using cetyl trimethyl ammonium bromide (CTAB) micelles as soft template and tetraethoxysilane (TEOS) as silica precursor. SEM, TEM, FT-IR, XRD, DLS and BET-BJH were carried out to characterize the morphology and structure of as-obtained samples. The results demonstrated that the samples were amorphous with a hollow structure and huge specific surface area. The growth of HSS was an inward-growth mechanism along template. Notably, we have provided a new and interesting fundamental principle for HSS materials by precisely controlling the ethanol-to-water volume ratio. In addition, the as-obtained HSS were mixed with waterborne polyurethane (WPU) to prepare WPU/HSS composite membrane. Various characterizations (SEM, TEM, FT-IR and TGA) revealed the morphology, polydispersity and adherence between HSS and WPU. Performance tests showed that the introduction of HSS can improve the water vapor permeability of composite membrane, promoting its water resistance and mechanical performance at the same time.

Thiolated DNA-based chemistry and control in the structure and optical properties of plasmonic nanoparticles with ultrasmall interior nanogap.

PubMed

Oh, Jeong-Wook; Lim, Dong-Kwon; Kim, Gyeong-Hwan; Suh, Yung Doug; Nam, Jwa-Min

2014-10-08

The design, synthesis and control of plasmonic nanostructures, especially with ultrasmall plasmonically coupled nanogap (∼1 nm or smaller), are of significant interest and importance in chemistry, nanoscience, materials science, optics and nanobiotechnology. Here, we studied and established the thiolated DNA-based synthetic principles and methods in forming and controlling Au core-nanogap-Au shell structures [Au-nanobridged nanogap particles (Au-NNPs)] with various interior nanogap and Au shell structures. We found that differences in the binding affinities and modes among four different bases to Au core, DNA sequence, DNA grafting density and chemical reagents alter Au shell growth mechanism and interior nanogap-forming process on thiolated DNA-modified Au core. Importantly, poly A or poly C sequence creates a wider interior nanogap with a smoother Au shell, while poly T sequence results in a narrower interstitial interior gap with rougher Au shell, and on the basis of the electromagnetic field calculation and experimental results, we unraveled the relationships between the width of the interior plasmonic nanogap, Au shell structure, electromagnetic field and surface-enhanced Raman scattering. These principles and findings shown in this paper offer the fundamental basis for the thiolated DNA-based chemistry in forming and controlling metal nanostructures with ∼1 nm plasmonic gap and insight in the optical properties of the plasmonic NNPs, and these plasmonic nanogap structures are useful as strong and controllable optical signal-generating nanoprobes.

3D Rheological Modeling of NW Intraplate Europe, Deciphering Spatial Integrated strength patterns, Mechanical Strong Layering and EET

NASA Astrophysics Data System (ADS)

Beekman, F.; Hardebol, N.; Cloetingh, S.; Tesauro, M.

2006-12-01

Better understanding of 3D rheological heterogeneity of the European Lithosphere provide the key to tie the recorded intraplate deformation pattern to stress fields transmitted into plate interior from plate boundary forces. The first order strain patterns result from stresses transmitted through the European lithosphere that is marked by a patchwork of high strength variability from inherited structural and compositional heterogeneities and upper mantle thermal perturbations. As the lithospheric rheology depends primarily on its spatial structure, composition and thermal estate, the 3D strength model for the European lithosphere relies on a 3D compositional model that yields the compositional heterogeneities and an iteratively calculated thermal cube using Fouriers law for heat conduction. The accurate appraisal of spatial strength variability results from proper mapping and integration of the geophysical compositional and thermal input parameters. Therefore, much attention has been paid to a proper description of first order structural and tectonic features that facilitate compilation of the compositional and thermal input models. As such, the 3D strength model reflects the thermo-mechanical structure inherited from the Europeans polyphase deformation history. Major 3D spatial mechanical strength variability has been revealed. The East-European and Fennoscandian Craton to the NE exhibit high strength (30-50 1012 N/m) from low mantle temperatures and surface heatflow of 35-60 mW/m2 while central and western Europe reflect a polyphase Phanerozoic thermo- tectonic history. Here, regions with high rigidity are formed primarily by patches of thermally stabilized Variscan Massifs (e.g. Rhenish, Armorican, Bohemian, and Iberian Massif) with low heatflow and lithospheric thickness values (50-65 mW/m2; 110-150 km) yielding strengths of ~15-25 1012 N/m. In contrast, major axis of weakened lithosphere coincides with Cenozoic Rift System (e.g. Upper and Lower Rhine Grabens, Pannonian Basin and Massif Central) attributed to the presence of tomographically imaged plumes. This study has elucidated the memory of the present-days Europeans lithosphere induced by compositional and thermal heterogeneities. The resulting lateral strength variations has a clear signature of the pst lithospheres polyphase deformation and also entails active tectonics, tectonically induced topography and surface processes.

On the structure of contact binaries. I - The contact discontinuity

NASA Technical Reports Server (NTRS)

Shu, F. H.; Lubow, S. H.; Anderson, L.

1976-01-01

The problem of the interior structure of contact binaries is reviewed, and a simple resolution of the difficulties which plague the theory is suggested. It is proposed that contact binaries contain a contact discontinuity between the lower surface of the common envelope and the Roche lobe of the cooler star. This discontinuity is maintained against thermal diffusion by fluid flow, and the transition layer is thin to the extent that the dynamical time scale is short in comparison with the thermal time scale. The idealization that the transition layer has infinitesimal thickness allows a simple formulation of the structure equations which are closed by appropriate jump conditions across the discontinuity. The further imposition of the standard boundary conditions suffices to define a unique model for the system once the chemical composition, the masses of the two stars, and the orbital separation are specified.

Educating the Public about Deep-Earth Science

NASA Astrophysics Data System (ADS)

Cronin, V. S.

2010-12-01

The nature of Earth’s interior is an active frontier of scientific research. Much of our current understanding of sub-crustal Earth is based on knowledge acquired in the last 2-3 decades, made possible by public funding and by dense seismic arrays, satellite remote sensing, increases in computer power that enable use of enhanced numerical techniques, improved theoretical and experimental knowledge of high PT mineral physics and chemistry, and a vigorous scientific community that has been trained to take advantage of these opportunities. An essential component of science is effective communication; therefore, providing for public education about science is a responsibility of the research community. Current public understanding of Earth’s interior is meager at best. In pre-college texts and in non-technical mass media, Earth's interior is typically visualized as an onion or baseball of concentric different-colored shells along whose upper surface "crustal" plates move like packages on conveyor belts of convecting mantle. Or the crust is thought to float on a molten mantle, as in the 19th century ideas of William Lowthian Green. Misconceptions about Earth that are brought to the undergraduate classroom must be confronted frankly and replaced by current understanding based on good science. Persistent ignorance has consequences. What do we want the public to know? First, the public should understand that knowledge of Earth's interior is important, not irrelevant. The public should know that deep-Earth processes result in Earth's dynamic magnetic field. Deep-Earth processes affect how radiation from the Sun reaches Earth, consequently affecting the atmosphere, the oceans, and the viability of life on Earth. The composition and differentiated structure of Earth's interior is a result of the early accretionary history of Earth and the Earth-Moon system. The public should also know that lithospheric tectonics, with all of its consequences (dynamic topography, volcanoes, earthquakes, resource concentrations, oceans, atmospheric composition and flow, possibly even life), is made possible by the specific characteristics of Earth's interior. Accepting that knowledge of Earth’s interior is important, the next task is to let the public know what we have learned about the deep Earth, and how we have developed that scientific knowledge. How do we incorporate uncertainty in this work? How do we test hypotheses? What are the current open questions about the deep Earth that we seek to address through ongoing or future scientific research? The cognitive distance between research experts and the public must be bridged -- an interpretive task that requires substantial expertise and collaboration. Reaching the ultimate audience (the general public) requires the education and active involvement of K-12+ teachers, education boards, textbook publishers and mass-media producers. Information must be packaged to suit each intended audience, at the appropriate cognitive level. The effectiveness of the education-and-outreach element of any research enterprise largely determines whether the processes and results of science are transferred successfully to the public consciousness.

Character-Defining Features of Contributing Buildings and Structures in the Fort Gordon, Georgia, Signal School Campus Historic District

DTIC Science & Technology

2016-07-01

conditioning CRM Cultural Resources Manager DPW Directorate of Public Works ERDC- CERL Engineer Research and Development Center – Construction Engineering...the interior character-defining features are unknown, but for undertakings that effect the interior the Cultural Resources Man- ager ( CRM ) should use...to the interior; the interior character-defining features are unknown but for undertakings that effect the interior, the CRM should use examples from

Mesoporous metal oxide microsphere electrode compositions and their methods of making

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parans Paranthaman, Mariappan; Bi, Zhonghe; Bridges, Craig A.

Compositions and methods of making are provided for treated mesoporous metal oxide microspheres electrodes. The compositions include microspheres with an average diameter between about 200 nanometers and about 10 micrometers and mesopores on the surface and interior of the microspheres. The methods of making include forming a mesoporous metal oxide microsphere composition and treating the mesoporous metal oxide microspheres by at least annealing in a reducing atmosphere, doping with an aliovalent element, and coating with a coating composition.

Pickup Ion Mass Spectrometry for Surface Bounded Exospheres and Composition Mapping of Lunar and Planetary Surfaces

NASA Technical Reports Server (NTRS)

Keller, J. W.; Zurbuchen, T. H.; Baragiola, R. A.; Cassidy, T. A.; Chornay, D. J.; Collier, M. R.; Hartle, R. E.; Johnson, R. E.; Killen, R. M.; Koehn, P.

2005-01-01

Many of the small to medium sized objects in the solar system can be characterized as having surface bounded exospheres, or atmospheres so tenuous that scale lengths for inter-particle collisions are much larger than the dimensions of the objects. The atmospheres of these objects are the product of their surfaces, both the surface composition and the interactions that occur on them and also their interiors when gases escape from there. Thus by studying surface bounded exospheres it is possible to develop insight into the composition and processes that are taking place on the surface and interiors of these objects. The Moon and Mercury are two examples of planetary bodies with surface bounded exospheres that have been studied through spectroscopic observations of sodium, potassium, and, on the moon, mass spectrometric measurements of lunar gases such as argon and helium.

Interior view of south and west walls (with instrumentation and ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior view of south and west walls (with instrumentation and equipment) of Oxidizer Conditioning Structure (T-28D) - Air Force Plant PJKS, Systems Integration Laboratory, Oxidizer Conditioning Structure, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

Interior view of west and north walls (with instrumentation and ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior view of west and north walls (with instrumentation and equipment) of Oxidizer Conditioning Structure (T-28D) - Air Force Plant PJKS, Systems Integration Laboratory, Oxidizer Conditioning Structure, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

Exploring Venus Interior Structure by Detection of Infrasonic Waves

NASA Astrophysics Data System (ADS)

Mimoun, D.; Cutts, J.; Stevenson, D.; Garcia, R. F.

2015-04-01

Knowledge of the interior structure of Venus is currently impeded by the limited time that a seismometer can survive in the atmosphere of Venus. We propose to remotely detect quakes by infrasonic measurements at the top of the cloud layer.

7. Interior of Building 1015 (land plane hangar), structural detail, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. Interior of Building 1015 (land plane hangar), structural detail, looking northeast - Naval Air Station Chase Field, Building 1015, Byrd Street, .82 mile South-southeast of intersection of Texas State Highway 202 & Independence Street, Beeville, Bee County, TX

8. Interior of Building 1015 (land plane hangar), structural detail, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. Interior of Building 1015 (land plane hangar), structural detail, looking northeast - Naval Air Station Chase Field, Building 1015, Byrd Street, .82 mile South-southeast of intersection of Texas State Highway 202 & Independence Street, Beeville, Bee County, TX

Theoretical predictions for the phase stability of dense binary mixtures

NASA Astrophysics Data System (ADS)

Macfarlane, J. J.

1983-08-01

A new approach is developed for evaluating the mixing properties of binary solutions at high pressure. This involves solving Poisson's equation throughout three-dimensional cubic lattices, consistent with Thomas-Fermi-Dirac (TFD) theory. Zero temperature calculations are carried out for a variety of compositions and crystal structures in 3 pressure groups relevant to Jovian planetary interiors. Pseudopotentials based on the two-component-plasma model (with a uniform electron background) are fitted to the solid-state results, and are then used in liquid-state calculations using hard-sphere perturbation theory. TFD results if H-He solutions find critical temperatures (above which all compositions are soluble) to be approx. 0.500, and 1500 K at pressures of 10, 100, and 1000 Mbar, respectively. These temperatures are much lower than those obtained using free electron perturbation theory, where Tcrit approx. 10,000 K at 10 Mbar.

Internal constitution and evolution of the moon.

NASA Technical Reports Server (NTRS)

Solomon, S. C.; Toksoz, M. N.

1973-01-01

The composition, structure and evolution of the moon's interior are narrowly constrained by a large assortment of physical and chemical data. Models of the thermal evolution of the moon that fit the chronology of igneous activity on the lunar surface, the stress history of the lunar lithosphere implied by the presence of mascons, and the surface concentrations of radioactive elements, involve extensive differentiation early in lunar history. This differentiation may be the result of rapid accretion and large-scale melting or of primary chemical layering during accretion; differences in present-day temperatures for these two possibilities are significant only in the inner 1000 km of the moon and may not be resolvable.

Predator- and Scavenger-Mediated Ecosystem Services Determined by Distance to Field-Forest Interface in the Maine Lowbush Blueberry Agroecosystem.

PubMed

Jones, Matthew S; Halteman, William A; Drummond, Francis A

2016-10-01

Predators and scavengers play a vital role in regulating insect pests, weeds, and vertebrate scat in perennial agroecosystems. Understanding how farm management practices and surrounding habitat influence these beneficial ecosystem services contributes to our understanding of these complex ecological systems and guides future management decisions. In a mensurative 2-yr study, we determined how different pest management strategies and surrounding forest composition influenced levels of sentinel insect pupae, weed seeds, and deer scat (feces) removal. Removal of these bioresources was measured within 12 commercial lowbush blueberry fields during 2011 and 2012; farms differed in surrounding landscape composition and farm management strategies. Both the removal of sentinel pupae and scat, was significantly higher within field interiors than at field edges and within adjacent forests. Additionally, farm management strategy interacted with field position to result in significantly higher scat removal in conventional field interiors than organic field interiors. Surrounding forest composition had variable effects on removal of materials. Our results indicate higher levels of activity within field centers as opposed to field edges; this is contrary to what has been observed in other perennial cropping agroecosystems. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Laboratory Simulations of Ammonia-Rich Oceans in Icy Worlds

NASA Technical Reports Server (NTRS)

Vance, S. D.; Brown, J. M.

2011-01-01

Improved equations of state for ammonia-water solutions are important for properly understanding the interiors of large icy satellites hosting deep interior oceans. Titan is the primary example of such a world, but water-rich dwarf planets Measurements of solution density are now possible at relevant pressures (above approx. 250 megapascals) using the Simulator for Icy World Interiors. Analysis of sound velocity measurements in aqueous magnesium sulfate obtained in our laboratory, shows a correction on the order of 5% to 700 megapascals (7 kilobar) from -20 to 100 C and to 3 m (approx. 30 percentage by weight) concentration. Accurate prediction of density as a function of pressure, temperature, and ammonia concentration are needed for interpretation of remote observations to address questions of interior liquid layer depth, composition, and fluid dynamics.

Getting Under Mars' Skin: The InSight Mission to the Deep Interior of Mars

NASA Astrophysics Data System (ADS)

Banerdt, W. B.; Asmar, S.; Banfield, D. J.; Christensen, U. R.; Clinton, J. F.; Dehant, V. M. A.; Folkner, W. M.; Garcia, R.; Giardini, D.; Golombek, M. P.; Grott, M.; Hudson, T.; Johnson, C. L.; Kargl, G.; Knapmeyer-Endrun, B.; Kobayashi, N.; Lognonne, P. H.; Maki, J.; Mimoun, D.; Mocquet, A.; Morgan, P.; Panning, M. P.; Pike, W. T.; Spohn, T.; Tromp, J.; Weber, R. C.; Wieczorek, M. A.; Russell, C. T.

2015-12-01

The InSight mission to Mars will launch in March of 2016, landing six months later in Elysium Planitia. In contrast to the 43 previous missions to Mars, which have thoroughly explored its surface features and chemistry, atmosphere, and searched for past or present life, InSight will focus on the deep interior of the planet. InSight will investigate the fundamental processes of terrestrial planet formation and evolution by performing the first comprehensive surface-based geophysical measurements on Mars. It will provide key information on the composition and structure of an Earth-like planet that has gone through most of the evolutionary stages of the Earth up to plate tectonics. The planet Mars can play a key role in understanding early terrestrial planet formation and evolution. Unlike the Earth, its overall structure appears to be relatively unchanged since the first few hundred million years after formation; unlike the Moon, it is large enough that the P-T conditions within the planet span an appreciable fraction of the terrestrial planet range. Thus the large-scale chemical and structural evidence preserved in Mars' interior should tell us a great deal about the processes of planetary differentiation and heat transport. InSight will undertake this investigation using the "traditional" geophysical techniques of seismology, precision tracking (for rotational dynamics), and heat flow measurement. The predominant challenge, in addition to the technical problems of the remote installation and operation of instruments on a distant and harsh planetary surface, comes from the practical limitation of working with data acquired from a single station. We will discuss how we overcome these limitations through the application of single-station seismic analysis techniques, which take advantage of some of the specific attributes of Mars, and global heat flow modeling, which allows the interpretation of a single measurement of a spatially inhomogeneous surface distribution.

Foliar nitrogen metabolism of adult Douglas-fir trees is affected by soil water availability and varies little among provenances.

PubMed

Du, Baoguo; Kreuzwieser, Jürgen; Dannenmann, Michael; Junker, Laura Verena; Kleiber, Anita; Hess, Moritz; Jansen, Kirstin; Eiblmeier, Monika; Gessler, Arthur; Kohnle, Ulrich; Ensminger, Ingo; Rennenberg, Heinz; Wildhagen, Henning

2018-01-01

The coniferous forest tree Douglas-fir (Pseudotsuga menziesii) is native to the pacific North America, and is increasingly planted in temperate regions worldwide. Nitrogen (N) metabolism is of great importance for growth, resistance and resilience of trees. In the present study, foliar N metabolism of adult trees of three coastal and one interior provenance of Douglas-fir grown at two common gardens in southwestern Germany (Wiesloch, W; Schluchsee, S) were characterized in two subsequent years. Both the native North American habitats of the seed sources and the common garden sites in Germany differ in climate conditions. Total and mineral soil N as well as soil water content were higher in S compared to W. We hypothesized that i) provenances differ constitutively in N pool sizes and composition, ii) N pools are affected by environmental conditions, and iii) that effects of environmental factors on N pools differ among interior and coastal provenances. Soil water content strongly affected the concentrations of total N, soluble protein, total amino acids (TAA), arginine and glutamate. Foliar concentrations of total N, soluble protein, structural N and TAA of trees grown at W were much higher than in trees at S. Provenance effects were small but significant for total N and soluble protein content (interior provenance showed lowest concentrations), as well as arginine, asparagine and glutamate. Our data suggest that needle N status of adult Douglas-fir is independent from soil N availability and that low soil water availability induces a re-allocation of N from structural N to metabolic N pools. Small provenance effects on N pools suggest that local adaptation of Douglas-fir is not dominated by N conditions at the native habitats.

Foliar nitrogen metabolism of adult Douglas-fir trees is affected by soil water availability and varies little among provenances

PubMed Central

Du, Baoguo; Kreuzwieser, Jürgen; Dannenmann, Michael; Junker, Laura Verena; Kleiber, Anita; Hess, Moritz; Jansen, Kirstin; Eiblmeier, Monika; Gessler, Arthur; Kohnle, Ulrich; Ensminger, Ingo; Rennenberg, Heinz

2018-01-01

The coniferous forest tree Douglas-fir (Pseudotsuga menziesii) is native to the pacific North America, and is increasingly planted in temperate regions worldwide. Nitrogen (N) metabolism is of great importance for growth, resistance and resilience of trees. In the present study, foliar N metabolism of adult trees of three coastal and one interior provenance of Douglas-fir grown at two common gardens in southwestern Germany (Wiesloch, W; Schluchsee, S) were characterized in two subsequent years. Both the native North American habitats of the seed sources and the common garden sites in Germany differ in climate conditions. Total and mineral soil N as well as soil water content were higher in S compared to W. We hypothesized that i) provenances differ constitutively in N pool sizes and composition, ii) N pools are affected by environmental conditions, and iii) that effects of environmental factors on N pools differ among interior and coastal provenances. Soil water content strongly affected the concentrations of total N, soluble protein, total amino acids (TAA), arginine and glutamate. Foliar concentrations of total N, soluble protein, structural N and TAA of trees grown at W were much higher than in trees at S. Provenance effects were small but significant for total N and soluble protein content (interior provenance showed lowest concentrations), as well as arginine, asparagine and glutamate. Our data suggest that needle N status of adult Douglas-fir is independent from soil N availability and that low soil water availability induces a re-allocation of N from structural N to metabolic N pools. Small provenance effects on N pools suggest that local adaptation of Douglas-fir is not dominated by N conditions at the native habitats. PMID:29566035

Simulating the influences of various fire regimes on caribou winter habitat

USGS Publications Warehouse

Rupp, T. Scott; Olson, Mark; Adams, Layne G.; Dale, Bruce W.; Joly, Kyle; Henkelman, Jonathan; Collins, William B.; Starfield, Anthony M.

2006-01-01

Caribou are an integral component of high‐latitude ecosystems and represent a major subsistence food source for many northern people. The availability and quality of winter habitat is critical to sustain these caribou populations. Caribou commonly use older spruce woodlands with adequate terrestrial lichen, a preferred winter forage, in the understory. Changes in climate and fire regime pose a significant threat to the long‐term sustainability of this important winter habitat. Computer simulations performed with a spatially explicit vegetation succession model (ALFRESCO) indicate that changes in the frequency and extent of fire in interior Alaska may substantially impact the abundance and quality of winter habitat for caribou. We modeled four different fire scenarios and tracked the frequency, extent, and spatial distribution of the simulated fires and associated changes to vegetation composition and distribution. Our results suggest that shorter fire frequencies (i.e., less time between recurring fires) on the winter range of the Nelchina caribou herd in eastern interior Alaska will result in large decreases of available winter habitat, relative to that currently available, in both the short and long term. A 30% shortening of the fire frequency resulted in a 3.5‐fold increase in the area burned annually and an associated 41% decrease in the amount of spruce–lichen forest found on the landscape. More importantly, simulations with more frequent fires produced a relatively immature forest age structure, compared to that which currently exists, with few stands older than 100 years. This age structure is at the lower limits of stand age classes preferred by caribou from the Nelchina herd. Projected changes in fire regime due to climate warming and/or additional prescribed burning could substantially alter the winter habitat of caribou in interior Alaska and lead to changes in winter range use and/or population dynamics.

Interactive controls of herbivory and fluvial dynamics on landscape vegetation patterns on the Tanana River floodplain, interior Alaska.

Treesearch

Lem G. Butler; Knut Kielland; T. Scott Rupp; Thomas A. Hanley

2007-01-01

We examined the interactive effects of mammalian herbivory and fluvial dynamics on vegetation dynamics and composition along the Tanana River in interior Alaska between Fairbanks and Manley Hot Springs. We used a spatially explicit model of landscape dynamics (ALFRESCO) to simulate vegetation changes on a 1-year time-step. The model was run for 250 years and was...

Determining building interior structures using compressive sensing

NASA Astrophysics Data System (ADS)

Lagunas, Eva; Amin, Moeness G.; Ahmad, Fauzia; Nájar, Montse

2013-04-01

We consider imaging of the building interior structures using compressive sensing (CS) with applications to through-the-wall imaging and urban sensing. We consider a monostatic synthetic aperture radar imaging system employing stepped frequency waveform. The proposed approach exploits prior information of building construction practices to form an appropriate sparse representation of the building interior layout. We devise a dictionary of possible wall locations, which is consistent with the fact that interior walls are typically parallel or perpendicular to the front wall. The dictionary accounts for the dominant normal angle reflections from exterior and interior walls for the monostatic imaging system. CS is applied to a reduced set of observations to recover the true positions of the walls. Additional information about interior walls can be obtained using a dictionary of possible corner reflectors, which is the response of the junction of two walls. Supporting results based on simulation and laboratory experiments are provided. It is shown that the proposed sparsifying basis outperforms the conventional through-the-wall CS model, the wavelet sparsifying basis, and the block sparse model for building interior layout detection.

Planning Bepicolombo MPO Science Operations to study Mercury Interior

NASA Astrophysics Data System (ADS)

De La Fuente, Sara; Carasa, Angela; Ortiz, Iñaki; Rodriguez, Pedro; Casale, Mauro; Benkhoff, Johannes; Zender, Joe

2017-04-01

BepiColombo is an Interdisciplinary Cornerstone ESA-JAXA Mission to Mercury, with two orbiters, the ESA Mercury Planetary Orbiter (MPO) and the JAXA Mercury Magnetospheric Orbiter (MMO) dedicated to study of the planet and its magnetosphere. The MPO, is a three-axis-stabilized, nadir-pointing spacecraft which will be placed in a polar orbit, providing excellent spatial resolution over the entire planet surface. The MPO's scientific payload comprises 11 instrument packages, including laser altimeter, cameras and the radio science experiment that will be dedicated to the study of Mercury's interior: structure, composition, formation and evolution. The planning of the science operations to be carried out by the Mercury's interior scientific instruments will be done by the SGS located at the European Space Astronomy Centre (ESAC), in conjunction with the scientific instrument teams. The process will always consider the complete nominal mission duration, such that the contribution of the scheduled science operations to the science objectives, the total data volume generated, and the seasonal interdependency, can be tracked. The heart of the science operations planning process is the Observations Catalogue (OC), a web-accessed database to collect and analyse all science operations requests. From the OC, the SGS will first determine all science opportunity windows compatible with the spacecraft operational constraints. Secondly, only those compatible with the resources (power and data volume) and pointing constraints will be chosen, including slew feasibility.

Dissipation in the deep interiors of Ganymede and Europa

NASA Astrophysics Data System (ADS)

Hussmann, Hauke; Shoji, Daigo; Steinbruegge, Gregor; Stark, Alexander; Sohl, Frank

2017-04-01

Jupiter's satellites are subject to strong tidal forces which result in variations of the gravitational potential and deformations of the satellites' surfaces on the diurnal tidal cycle. Tidal flexing in the deep interiors can be a significant heat source for the satellites' thermal-orbital evolution. Whereas typical structure models of Europa consist of a core, a silicate mantle, an ocean and an outer ice-I shell [1], pressures inside Ganymede are sufficient for high-pressure ice phases to occur between the silicate mantle and the ocean [2]. With current data it is unknown whether the deep interiors (i.e., Europa's silicate shell and Ganymede's silicate mantle and/or high-pressure ice layer) are dissipative. Other possibilities would be that the dissipation rates are in general very low (unlikely at least for Europa due to recent observations) or that dissipative processes are mainly occurring in the ice-I shell and/or ocean. Thus, for evaluations of the heating state of these satellites, it is important to measure the magnitude of the interior dissipation. However, observation of the interior layers such as high-pressure ice layers is more challenging than that of the surface ice-I layer. Here we suggest a method to constrain the dissipation states of the deep interiors of Ganymede and Europa by altimetry and gravity measurements from an orbiting or multi-flyby spacecraft. Tidal variations are generally described by the Love numbers k2 and h2 for the tide-induced potential variation due to internal mass redistribution and the radial surface displacement, respectively. The phase-lags of these complex numbers contain information about the rheological and dissipative states of the satellites. For the satellites we assume a decoupling of the outer ice-shell from the deep interior by a liquid subsurface water ocean. We show that, in this case, the phase-lag difference between the lags of k2 and h2 can provide information on the rheological and thermal state of the deep interiors if the viscosities of the deeper layers are small (the phase-lag difference is almost independent of the dissipation in the surface layer). In case of Ganymede, phase-lag differences can reach values of a few degrees for high-pressure ice viscosities of 1e13-1e14 Pa s (around the lower boundary at its melting temperature) and would indicate a highly dissipative state of the deep interior. In this case, in contrast to the phase lags itself, the phase-lag difference is dominated by dissipation in the high-pressure ice layer rather than dissipation within the ice-I shell. These phase lags would be detectable from spacecraft in orbit around the satellite [3]. For Europa the phase-lag difference could reach values exceeding 20 deg if the silicate mantle contains melt and phase-lag measurements could help distinguish between (1) a hot dissipative (melt-containing) silicate mantle which would in thermal equilibrium correspond to a very thin outer ice-I shell and (2) a cold deep interior implying that dissipation would mainly occur in a thick (several tens of km) outer ice-I shell. These measurements are highly relevant for ESA's Jupiter Icy Moons Explorer (JUICE) and NASA's Europa Multiple Flyby Mission, both targeted for the Jupiter system. References: [1] Schubert, G., F. Sohl and H. Hussmann 2009. Interior of Europa. In: Europa, (R.T. Pappalardo, W.B. McKinnon, K. Khurana, Eds.), University of Arizona Press, pp. 353 - 368. [2] Schubert G., J. D. Anderson, T. Spohn, and W. B. McKinnon 2004. Interior composition, structure, and dynamics of the Galilean satellites. In: F. Bagenal, T. E. Dowling, and W. B. McKinnon (eds.) Jupiter. The Planet, Satellites, and Magnetosphere, pp. 281-306. Cambridge University Press. [3] Hussmann, H., D. Shoji, G. Steinbrügge, A. Stark, F. Sohl 2016. Constraints on dissipation in the deep interiors of Ganymede and Europa from tidal phase-lags. Cel. Mech. Dyn. Astr. 126, 131 - 144.

Geology and impact features of Vargeão Dome, southern Brazil

NASA Astrophysics Data System (ADS)

Crósta, Alvaro P.; Kazzuo-Vieira, César; Pitarello, Lidia; Koeberl, Christian; Kenkmann, Thomas

2012-01-01

Vargeão Dome (southern Brazil) is a circular feature formed in lava flows of the Lower Cretaceous Serra Geral Formation and in sandstones of the Paraná Basin. Even though its impact origin was already proposed in the 1980s, little information about its geological and impact features is available in the literature. The structure has a rim-rim diameter of approximately 12 km and comprises several ring-like concentric features with multiple concentric lineaments. The presence of a central uplift is suggested by the occurrence of deformed sandstone strata of the Botucatu and Pirambóia formations. We present the morphological/structural characteristics of Vargeão Dome, characterize the different rock types that occur in its interior, mainly brecciated volcanic rocks (BVR) of the Serra Geral Formation, and discuss the deformation and shock features in the volcanic rocks and in sandstones. These features comprise shatter cones in sandstone and basalt, as well as planar microstructures in quartz. A geochemical comparison of the target rock equivalents from outside the structure with the shocked rocks from its interior shows that both the BVRs and the brecciated sandstone have a composition largely similar to that of the corresponding unshocked lithologies. No traces of meteoritic material have been found so far. The results confirm the impact origin of Vargeão Dome, making it one of the largest among the rare impact craters in basaltic targets known on Earth.

54. INTERIOR OF APRON SUSPENSION STRUCTURE SHOWING APRON COUNTERWEIGHT SYSTEM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

54. INTERIOR OF APRON SUSPENSION STRUCTURE SHOWING APRON COUNTERWEIGHT SYSTEM OF CABLES AND PULLEYS ABOVE BRIDGE NOS. 12 AND 11. LOOKING NORTH. - Greenville Yard, Transfer Bridge System, Port of New York/New Jersey, Upper New York Bay, Jersey City, Hudson County, NJ

3D radar wavefield tomography of comet interiors

NASA Astrophysics Data System (ADS)

Sava, Paul; Asphaug, Erik

2018-04-01

Answering fundamental questions about the origin and evolution of small planetary bodies hinges on our ability to image their surface and interior structure in detail and at high resolution. The interior structure is not easily accessible without systematic imaging using, e.g., radar transmission and reflection data from multiple viewpoints, as in medical tomography. Radar tomography can be performed using methodology adapted from terrestrial exploration seismology. Our feasibility study primarily focuses on full wavefield methods that facilitate high quality imaging of small body interiors. We consider the case of a monostatic system (co-located transmitters and receivers) operated in various frequency bands between 5 and 15 MHz, from a spacecraft in slow polar orbit around a spinning comet nucleus. Using realistic numerical experiments, we demonstrate that wavefield techniques can generate high resolution tomograms of comets nuclei with arbitrary shape and complex interior properties.

On the Interior of Carbon-Rich Exoplanets: New Insight from Si-C System at Ultra High Pressure

NASA Astrophysics Data System (ADS)

Miozzi Ferrini, F.; Morard, G.; Antonangeli, D.; Clark, A. N.; Edmund, E.; Fiquet, G.; Mezouar, M.

2017-12-01

The variability in the mass/radius ratio of the more than 3200 exoplanets discovered so far, is a direct consequence of the large diversity of their internal composition. Exoplanets with a mass between 1 and 10 times the mass of the Earth are typically referred to as super-Earths, and their mineralogical composition depends on that of the protoplanetary disk. The key variable in determining the chemical makeup of such planets is the C/O ratio. Values of C/O ratio smaller than 0.8 correspond to an interior dominated by silicates (e.g. terrestrial planets), whereas for C/O ratios > 0.8 the interior is enriched in carbon. In these C-rich planets, Si may form carbides instead of silicates (Duffy et al., 2015). The detection of planet 55 Cancri e, with a particularly high C/O ratio, has increased the interest in carbon-rich planets. 55 Cancri e has been modelled as a layered structure made by different assemblages of carbon, silicon and iron (Madhusudan et al., 2012). However, the accuracy of such type of models suffers the lack of experimental data on the Si - C system at extreme conditions of pressure and temperature. Experimental equations of state are limited to 80 GPa (Nisr et al., 2017) and little is known about subsolidus relation, with only one theoretical study from Wilson and Militzer (2004) at multi-megabar pressures. Here we present experiments on SiC samples by synchrotron X-ray diffraction, in laser heated diamond anvil cell between 30-200 GPa and 300-3500 K. The results show evidences of coexistence of SiC with Si or C, without the appearance of intermediate compounds. Moreover, between 60 and 75 GPa, SiC undergoes a phase transition from the zinc blend structure (B3), to the rock salt structure (B1). This phase transition, also reported in previous literature work (e.g. Daviau and Lee, 2017), corresponds to a change in the atoms coordination, and is accompanied by an important volume reduction. Acknowledgements: This work was supported by the ERC PlanetDive advanced grant 670787. ReferencesDuffy T. 2015. Mineralogy of Super-Earth Planets. Treatise on Geophysics. Volume 2. Elsevier Daviau K. & Lee K.K.M. 2017. Physical Review B, 95(13), 134108 Madhusudhan N. et al., 2012. Astrophys. J. 759, L40. Nisr C. et al., 2017. J. Geophys. Res. Planets., 122, 124-133. Wilson H.F. & Militzer B. 2004. Astrophys. J. 793, 34.

Equation of state of iron under core conditions of large rocky exoplanets

NASA Astrophysics Data System (ADS)

Smith, Raymond F.; Fratanduono, Dayne E.; Braun, David G.; Duffy, Thomas S.; Wicks, June K.; Celliers, Peter M.; Ali, Suzanne J.; Fernandez-Pañella, Amalia; Kraus, Richard G.; Swift, Damian C.; Collins, Gilbert W.; Eggert, Jon H.

2018-04-01

The recent discovery of thousands of planets outside our Solar System raises fundamental questions about the variety of planetary types and their corresponding interior structures and dynamics. To better understand these objects, there is a strong need to constrain material properties at the extreme pressures found within planetary interiors1,2. Here we used high-powered lasers at the National Ignition Facility to ramp compress iron over nanosecond timescales to 1.4 TPa (14 million atmospheres)—a pressure four times higher than for previous static compression data. A Lagrangian sound-speed analysis was used to determine pressure, density and sound speed along a continuous isentropic compression path. Our peak pressures are comparable to those predicted at the centre of a terrestrial-type exoplanet of three to four Earth masses3, representing the first absolute equation of state measurements for iron at such conditions. These results provide an experiment-based mass-radius relationship for a hypothetical pure iron planet that can be used to evaluate plausible compositional space for large, rocky exoplanets.

KSC-05PD-0019

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. From a vantage point above, a worker observes the Deep Impact spacecraft exposed after removal of the canister and protective cover. Next the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0075

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. The Deep Impact spacecraft waits inside the mobile service tower on Launch Pad 17-B, Cape Canaveral Air force Station, Fla., for fairing installation. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nosecone, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0079

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. Inside the mobile service tower on Launch Pad 17-B, Cape Canaveral Air force Station, Fla., the partly enclosed Deep Impact spacecraft (background) waits while the second half of the fairing (foreground left) moves toward it. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nosecone, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0076

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. Inside the mobile service tower on Launch Pad 17-B, Cape Canaveral Air force Station, Fla., the first half of the fairing is moved toward the Deep Impact spacecraft for installation. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nosecone, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0078

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. Inside the mobile service tower on Launch Pad 17-B, Cape Canaveral Air force Station, Fla., the first half of the fairing is moved into place around the Deep Impact spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nosecone, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0074

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. The Deep Impact spacecraft waits inside the mobile service tower on Launch Pad 17-B, Cape Canaveral Air force Station, Fla., for fairing installation. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nosecone, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0077

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. Inside the mobile service tower on Launch Pad 17-B, Cape Canaveral Air force Station, Fla., the first half of the fairing is moved into place around the Deep Impact spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nosecone, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0073

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. The Deep Impact spacecraft waits inside the mobile service tower on Launch Pad 17-B, Cape Canaveral Air force Station, Fla., for fairing installation. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nosecone, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0080

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. Inside the mobile service tower on Launch Pad 17-B, Cape Canaveral Air force Station, Fla., workers attach the two halves of the fairing around the Deep Impact spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth nosecone, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

Equation of state of iron under core conditions of large rocky exoplanets

NASA Astrophysics Data System (ADS)

Smith, Raymond F.; Fratanduono, Dayne E.; Braun, David G.; Duffy, Thomas S.; Wicks, June K.; Celliers, Peter M.; Ali, Suzanne J.; Fernandez-Pañella, Amalia; Kraus, Richard G.; Swift, Damian C.; Collins, Gilbert W.; Eggert, Jon H.

2018-06-01

The recent discovery of thousands of planets outside our Solar System raises fundamental questions about the variety of planetary types and their corresponding interior structures and dynamics. To better understand these objects, there is a strong need to constrain material properties at the extreme pressures found within planetary interiors1,2. Here we used high-powered lasers at the National Ignition Facility to ramp compress iron over nanosecond timescales to 1.4 TPa (14 million atmospheres)—a pressure four times higher than for previous static compression data. A Lagrangian sound-speed analysis was used to determine pressure, density and sound speed along a continuous isentropic compression path. Our peak pressures are comparable to those predicted at the centre of a terrestrial-type exoplanet of three to four Earth masses3, representing the first absolute equation of state measurements for iron at such conditions. These results provide an experiment-based mass-radius relationship for a hypothetical pure iron planet that can be used to evaluate plausible compositional space for large, rocky exoplanets.

High Pressure Cosmochemistry of Major Planetary Interiors: Laboratory Studies of the Water-rich Region of the System Ammonia-water

NASA Technical Reports Server (NTRS)

Nicol, M.; Johnson, M.; Koumvakalis, A. S.

1985-01-01

The behavior of gas-ice mixtures in major planets at very high pressures was studied. Some relevant pressure-temperature-composition (P-T-X) regions of the hydrogen (H2)-helium (He)-water (H2O-ammonia (NH3)-methane (CH4) phase diagram were determined. The studies, and theoretical model, of the relevant phases, are needed to interpret the compositions of ice-gas systems at conditions of planetary interest. The compositions and structures of a multiphase, multicomponent system at very high pressures care characterized, and the goal is to characterize this system over a wide range of low and high temperatures. The NH3-H2O compositions that are relevant to planetary problems yet are easy to prepare were applied. The P-T surface of water was examined and the corresponding surface for NH3 was determined. The T-X diagram of ammonia-water at atmospheric pressure was studied and two water-rich phases were found, NH3-2H2O (ammonia dihydrate), which melts incongruently, and NH3.H2O (ammonia monohydrate), which is nonstoichiometric and melts at a higher temperature than the dihydrate. It is suggested that a P-T surface at approximately the monohydrate composition and the P-X surface at room temperature is determined.

Hydrogen isotopes in lunar volcanic glasses and melt inclusions reveal a carbonaceous chondrite heritage.

PubMed

Saal, Alberto E; Hauri, Erik H; Van Orman, James A; Rutherford, Malcolm J

2013-06-14

Water is perhaps the most important molecule in the solar system, and determining its origin and distribution in planetary interiors has important implications for understanding the evolution of planetary bodies. Here we report in situ measurements of the isotopic composition of hydrogen dissolved in primitive volcanic glass and olivine-hosted melt inclusions recovered from the Moon by the Apollo 15 and 17 missions. After consideration of cosmic-ray spallation and degassing processes, our results demonstrate that lunar magmatic water has an isotopic composition that is indistinguishable from that of the bulk water in carbonaceous chondrites and similar to that of terrestrial water, implying a common origin for the water contained in the interiors of Earth and the Moon.

Design Development of a Combined Deployment and Pointing System for the International Space Station Neutron Star Interior Composition Explorer Telescope

NASA Technical Reports Server (NTRS)

Budinoff, Jason; Gendreau, Keith; Arzoumanian, Zaven; Baker, Charles; Berning, Robert; Colangelo, Todd; Holzinger, John; Lewis, Jesse; Liu, Alice; Mitchell, Alissa;

Design Development of a Combined Deployment and Pointing System for the International Space Station Neutron Star Interior Composition Explorer Telescope

NASA Technical Reports Server (NTRS)

Budinoff, Jason; Gendreau, Keith; Arzoumanian, Zaven; Baker, Charles; Berning, Robert; Colangelo, TOdd; Holzinger, John; Lewis, Jesse; Liu, Alice; Mitchell, Alissa;

Develop Critical Profilometers to Meet Current and Future Composite Overwrapped Pressure Vessel (COPV) Interior Inspection Needs

NASA Technical Reports Server (NTRS)

Saulsberry, Regor L.

2010-01-01

The objective of this project is to develop laser profilometer technology that can efficiently inspect and map the inside of composite pressure vessels for flaws such as liner buckling, pitting, or other surface imperfections. The project will also provide profilometers that can directly support inspections of flight vessels during development and qualification programs and subsequently be implemented into manufacturing inspections to screen out vessels with "out of family" liner defects. An example interior scan of a carbon overwrapped bottle is shown in comparison to an external view of the same bottle (Fig. 1). The internal scan is primarily of the cylindrical portion, but extends about 0.15 in. into the end cap area.

Electromagnetic Scattering Analysis of Large Size Asteroids/Comets for Reflection/Transmission Tomography (RTT)

NASA Technical Reports Server (NTRS)

Deshpande, Manohar

2011-01-01

A precise knowledge of the interior structure of asteroids, comets, and Near Earth Objects (NEO) is important to assess the consequences of their impacts with the Earth and develop efficient mitigation strategies. Knowledge of their interior structure also provides opportunities for extraction of raw materials for future space activities. Low frequency radio sounding is often proposed for investigating interior structures of asteroids and NEOs. For designing and optimizing radio sounding instrument it is advantageous to have an accurate and efficient numerical simulation model of radio reflection and transmission through large size bodies of asteroid shapes. In this presentation we will present electromagnetic (EM) scattering analysis of electrically large size asteroids using (1) a weak form formulation and (2) also a more accurate hybrid finite element method/method of moments (FEM/MOM) to help estimate their internal structures. Assuming the internal structure with known electrical properties of a sample asteroid, we first develop its forward EM scattering model. From the knowledge of EM scattering as a function of frequency and look angle we will then present the inverse scattering procedure to extract its interior structure image. Validity of the inverse scattering procedure will be presented through few simulation examples.

Protein-Protein Interaction Site Predictions with Three-Dimensional Probability Distributions of Interacting Atoms on Protein Surfaces

PubMed Central

Chen, Ching-Tai; Peng, Hung-Pin; Jian, Jhih-Wei; Tsai, Keng-Chang; Chang, Jeng-Yih; Yang, Ei-Wen; Chen, Jun-Bo; Ho, Shinn-Ying; Hsu, Wen-Lian; Yang, An-Suei

2012-01-01

Protein-protein interactions are key to many biological processes. Computational methodologies devised to predict protein-protein interaction (PPI) sites on protein surfaces are important tools in providing insights into the biological functions of proteins and in developing therapeutics targeting the protein-protein interaction sites. One of the general features of PPI sites is that the core regions from the two interacting protein surfaces are complementary to each other, similar to the interior of proteins in packing density and in the physicochemical nature of the amino acid composition. In this work, we simulated the physicochemical complementarities by constructing three-dimensional probability density maps of non-covalent interacting atoms on the protein surfaces. The interacting probabilities were derived from the interior of known structures. Machine learning algorithms were applied to learn the characteristic patterns of the probability density maps specific to the PPI sites. The trained predictors for PPI sites were cross-validated with the training cases (consisting of 432 proteins) and were tested on an independent dataset (consisting of 142 proteins). The residue-based Matthews correlation coefficient for the independent test set was 0.423; the accuracy, precision, sensitivity, specificity were 0.753, 0.519, 0.677, and 0.779 respectively. The benchmark results indicate that the optimized machine learning models are among the best predictors in identifying PPI sites on protein surfaces. In particular, the PPI site prediction accuracy increases with increasing size of the PPI site and with increasing hydrophobicity in amino acid composition of the PPI interface; the core interface regions are more likely to be recognized with high prediction confidence. The results indicate that the physicochemical complementarity patterns on protein surfaces are important determinants in PPIs, and a substantial portion of the PPI sites can be predicted correctly with the physicochemical complementarity features based on the non-covalent interaction data derived from protein interiors. PMID:22701576

The Impact of Large Urban Structural Elements on Traffic Flow   a Case Study of Danwei and Xiaoqu in Shanghai

NASA Astrophysics Data System (ADS)

Lyu, H.; Ding, L.; Fan, H.; Meng, L.

2017-09-01

Danwei (working unit) and Xiaoqu (residential community) are two typical and unique structural urban elements in China. The interior roads of Danwei and Xiaoqu are usually not accessible for the public. Recently, there is a call for opening these interior roads to the public to improve road network structure and optimize traffic flow. In this paper we investigate the impact of Danwei and Xiaoqu on their neighbouring traffic quantitatively. By taking into consideration of origins and destinations (ODs) distributions and route selection behaviours (e.g., shortest paths), we propose an extended betweenness centrality to investigate the traffic flow in two scenarios 1) the interior roads of Danwei and Xiaoqu are excluded from urban road network, 2) the interior roads are integrated into road network. A Danwei and a Xiaoqu in Shanghai are used as the study area. The preliminary results show the feasibility of our extended betweenness centrality in investigating the traffic flow patterns and reveal the quantitative changes of the traffic flow after opening interior roads.

General interior view of parking structure in Section A from ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General interior view of parking structure in Section A from level B2 showing "Levinson Steel Co." on exposed beams and diagonal steel supports, looking southeast. (BH) - World Trade Center Site, Bounded by Vesey, Church, Liberty Streets, & Route 9A, New York County, NY

Battery Honeycutt, view from interior of main structure through southwest ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Battery Honeycutt, view from interior of main structure through southwest doorway toward frame, view to southwest - Fort McKinley, Battery Honeycutt Observation Station, East side of East Side Drive, approximately 225 feet south of Cove Side Drive, Great Diamond Island, Portland, Cumberland County, ME

The effects of fire on the thermal stability of permafrost in lowland and upland black spruce forests of interior Alaska in a changing climate

Treesearch

E.E. Jafarov; V.E. Romanovsky; H. Genet; A.D. McGuire; S.S. Marchenko

2013-01-01

Fire is an important factor controlling the composition and thickness of the organic layer in the black spruce forest ecosystems of interior Alaska. Fire that burns the organic layer can trigger dramatic changes in the underlying permafrost, leading to accelerated ground thawing within a relatively short time. In this study, we addressed the following questions. (1)...

Experimental Fractional Crystallization of the Lunar Magma Ocean

NASA Technical Reports Server (NTRS)

Rapp, J. F.; Draper, D. S.

2012-01-01

The current paradigm for lunar evolution is of crystallization of a global scale magma ocean, giving rise to the anorthositic crust and mafic cumulate interior. It is thought that all other lunar rocks have arisen from this differentiated interior. However, until recently this paradigm has remained untested experimentally. Presented here are the first experimental results of fractional crystallization of a Lunar Magma Ocean (LMO) using the Taylor Whole Moon (TWM) bulk lunar composition [1].

The Interior Analysis and 3-D Reconstruction of Internally-Mixed Light-Absorbing Atmospheric Particles

NASA Astrophysics Data System (ADS)

Conny, J. M.; Collins, S. M.; Anderson, I.; Herzing, A.

2010-12-01

Carbon-containing atmospheric particles may either absorb solar or outgoing long-wave radiation or scatter solar radiation, and thus, affect Earth’s radiative balance in multiple ways. Light-absorbing carbon that is common in urban air particles such as industrial coke dust, road dust, and diesel soot, often exists in the same particle with other phases that contain, for example, aluminum, calcium, iron, and sulfur. While the optical properties of atmospheric particles in general depend on overall particle size and shape, the inhomogeneity of chemical phases within internally-mixed particles may also greatly affect particle optical properties. In this study, a series of microscopic approaches were used to identify individual light-absorbing coarse-mode particles and to assess their interior structure and composition. Particle samples were collected in 2004 from one of the U.S. EPA’s Los Angeles Particulate Matter Supersites, and were likely affected substantially by road dust and construction dust. First, bright-field and dark-field light microscopy and computer-controlled scanning electron microscopy (SEM) with energy-dispersive x-ray spectroscopy (EDX) were used to distinguish predominantly light-absorbing carbonaceous particles from other particle types such as mineral dust, sea salt, and brake wear. Second, high-resolution SEM-EDX elemental mapping of individual carbonaceous particles was used to select particles with additional elemental phases that exhibited spatial inhomogeneity. Third, focused ion-beam SEM (FIB-SEM) with EDX was used to slice through selected particles to expose interior surfaces and to determine the spatial distribution of element phases throughout the particles. Fourth, study of the interior phases of a particle was augmented by the transmission electron microscopy (TEM) of a thin section of the particle prepared by FIB-SEM. Here, electron energy loss spectroscopy with TEM was used to study chemical bonding in the carbonaceous phase. Finally, automated serial slicing and imaging in the FIB-SEM generated a stack of secondary electron images of the particles’ interior surfaces that allowed for the 3-D reconstruction of the particles, a process known as FIB tomography. Interior surface of light-absorbing carbonaceous particle from FIB-SEM analysis.

Lather (Interior Systems Mechanic). Occupational Analyses Series.

ERIC Educational Resources Information Center

Chapman, Mike; Chapman, Carol; MacLean, Margaret

This analysis covers tasks performed by a lather, an occupational title some provinces and territories of Canada have also identified as drywall and acoustical mechanic; interior systems installer; and interior systems mechanic. A guide to analysis discusses development, structure, and validation method; scope of the occupation; trends; and…

Modeling the Effects of Fire Frequency and Severity on Forests in the Northwestern United States

USGS Publications Warehouse

Busing, Richard T.; Solomon, Allen M.

2006-01-01

This study used a model of forest dynamics (FORCLIM) and actual forest survey data to demonstrate the effects of various fire regimes on different forest types in the Pacific Northwest. We examined forests in eight ecoregions ranging from wet coastal forests dominated by Pseudotsuga menziesii and other tall conifers to dry interior forests dominated by Pinus ponderosa. Fire effects simulated as elevated mortality of trees based on their species and size did alter forest structure and species composition. Low frequency fires characteristic of wetter forests (return interval >200 yr) had minor effects on composition. When fires were severe, they tended to reduce total basal area with little regard to species differences. High frequency fires characteristic of drier forests (return interval <30 yr) had major effects on species composition and on total basal area. Typically, they caused substantial reductions in total basal area and shifts in dominance toward highly fire tolerant species. With the addition of fire, simulated basal areas averaged across ecoregions were reduced to levels approximating observed basal areas.

Durability of wood-plastic composite lumber

Treesearch

Rebecca E. Ibach

2010-01-01

Wood-plastic composite (WPC) lumber has been marketed as a low-maintenance, high-durability product. Retail sales in the United States were slightly less than $1 billion in 2008. Applications include docking, railing, windows, doors, fencing, siding, moldings, landscape timbers, car interior parts, and furniture. The majority of these products are used outdoors and...

Bumble bees (Hymenoptera: Apidae: Bombus spp.) of interior Alaska: Species composition, distribution, seasonal biology, and parasites

USDA-ARS?s Scientific Manuscript database

Despite the ecological and agricultural significance of bumble bees in Alaska, very little is known and published about this important group at the regional level. The objectives of this study were to provide baseline data on species composition, distribution, seasonal biology, and parasites of the ...

Stream dissolved organic matter bioavailability and composition in watersheds underlain with discontinuous permafrost

Treesearch

Kelly L. Balcarczyk; Jeremy B. Jones; Rudolf Jaffe; Nagamitsu Maie

2009-01-01

We examined the impact of permafrost on dissolved organic matter (DOM) composition in Caribou-Poker Creeks Research Watershed (CPCRW), a watershed underlain with discontinuous permafrost, in interior Alaska. The stream draining the high permafrost watershed had higher DOC and dissolved organic nitrogen (DON) concentrations, higher DOCDON and greater specific...

On ethics and the earthquake resistant interior design of buildings.

PubMed

Hurol, Yonca

2014-03-01

The most common tectonic quality of modern structures, such as frame systems, is their flexibility; they are open for change. Although this characteristic is a big advantage in comparison to the inflexible masonry structures of the past, it might also create some serious problems, such as e.g. the lack of safety in the event of an earthquake, if the flexibility is not used consciously by architects and interior designers. This article attempts to define and establish some rules for the interior design of buildings with reinforced concrete frame systems. The rules for making subtractions from these structures and extending them by making additions to them are contained within this article. The main objective of this article is to derive some ethical values from these rules. Thus, the conclusion of the article focuses on the derivation of some ethical values for achieving earthquake resistant interior design of buildings with reinforced concrete frame systems.

The Primordial Entropy of Jupiter

NASA Astrophysics Data System (ADS)

Cumming, Andrew; Helled, Ravit; Venturini, Julia

2018-04-01

The formation history of giant planets determines their primordial structure and consequent evolution. We simulate various formation paths of Jupiter to determine its primordial entropy, and find that a common outcome is for proto-Jupiter to have non-convective regions in its interior. We use planet formation models to calculate how the entropy and post-formation luminosity depend on model properties such as the solid accretion rate and opacity, and show that the gas accretion rate and its time evolution play a key role in determining the entropy profile. The predicted luminosity of Jupiter shortly after formation varies by a factor of 2-3 for different choices of model parameters. We find that entropy gradients inside Jupiter persist for ˜10 Myr after formation. We suggest that these gradients should be considered together with heavy-element composition gradients when modeling Jupiter's evolution and internal structure.

Interior Structure of Ceres Artist Concept

NASA Image and Video Library

2016-08-03

This artist's concept shows a diagram of how the inside of Ceres could be structured, based on data about the dwarf planet's gravity field from NASA's Dawn mission. Using information about Ceres' gravity and topography, scientists found that Ceres is "differentiated," which means that it has compositionally distinct layers at different depths. The densest layer is at the core, which scientists suspect is made of hydrated silicates. Above that is a volatile-rich shell, topped with a crust of mixed materials. This research teaches scientists about what internal processes could have occurred during the early history of Ceres. It appears that, during a heating phase early in the history of Ceres, water and other light materials partially separated from rock. These light materials and water then rose to the outer layer of Ceres. http://photojournal.jpl.nasa.gov/catalog/PIA20867

The primordial entropy of Jupiter

NASA Astrophysics Data System (ADS)

Cumming, Andrew; Helled, Ravit; Venturini, Julia

2018-07-01

The formation history of giant planets determines their primordial structure and consequent evolution. We simulate various formation paths of Jupiter to determine its primordial entropy, and find that a common outcome is for proto-Jupiter to have non-convective regions in its interior. We use planet formation models to calculate how the entropy and post-formation luminosity depend on model properties such as the solid accretion rate and opacity, and show that the gas accretion rate and its time evolution play a key role in determining the entropy profile. The predicted luminosity of Jupiter shortly after formation varies by a factor of 2-3 for different choices of model parameters. We find that entropy gradients inside Jupiter persist for ˜10 Myr after formation. We suggest that these gradients should be considered together with heavy-element composition gradients when modelling Jupiter's evolution and internal structure.

Subspecies status and population genetic structure in Piping Plover (Charadrius melodus)

USGS Publications Warehouse

Miller, M.P.; Haig, S.M.; Gratto-Trevor, C. L.; Mullins, T.D.

2010-01-01

Piping Plover (Charadrius melodus) is a migratory shorebird that is listed as endangered in Canada and the U.S. Great Lakes and as threatened throughout the rest of its breeding and winter range. We undertook a comprehensive molecular-genetic investigation to (1) address subspecific taxonomy, (2) characterize population genetic structure, and (3) infer past bottlenecks and demographic processes in this species. Analyses included individuals from 23 U.S. states and Canadian provinces and were based on mitochondrial DNA sequences (580 base pairs, n = 245) and 8 nuclear microsatellite loci (n = 229). Our findings provide support for separate Atlantic and Interior subspecies (C. m. melodus and C. m. circumcinctus, respectively). Birds from the Great Lakes region were allied with the Interior subspecies and should be referred to as C. m. circumcinctus. Population genetic analyses illustrated stronger genetic structure among Atlantic than among Interior birds, which may reflect reduced natal- and breeding-site fidelity of Interior individuals. Furthermore, analyses suggested that Interior birds previously experienced genetic bottlenecks, whereas there was no evidence of such patterns in the Atlantic subspecies. We interpret these results in light of 25 years of range-wide census data. Overall, differences between Interior and Atlantic Piping Plovers may reflect differences in spatiotemporal stability of nesting habitat between regions. ?? 2010 The American Ornithologists' Union.

The composition and origin of the moon

NASA Technical Reports Server (NTRS)

Anderson, D. L.

1972-01-01

A model is presented of the moon as a high temperature condensate from the solar nebula. The Ca, Al, and Ti rich compounds condense first in a cooling nebula. The initial high temperature mineralogy is gehlenite, spinel, perovskite, Ca-Al-rich pyroxenes, and anorthite. Type 3 carbonaceous chondrites such as the Allende meteorite are composed primarily of these minerals and are highly enriched in refractories. These inclusions can yield basalt and anorthosite in the proportions required to eliminate the europium anomaly, leaving a residual spinel-melilite interior. The inferred high U content of the lunar interior, both from the Allende analogy and the high heat flow, indicates a high temperature interior. The model is consistent with extensive early, shallow melting at 3 A.E., and with high deep internal temperatures. It is predicted that the outer 250 km is rich in plagioclase and FeO. The low iron content of the interior raises the interior temperatures estimated from electrical conductivity by some 800 C.

11. Detail of the interior, looking through an interior doorway ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. Detail of the interior, looking through an interior doorway toward the front and east window. Note: This photograph shows that the building had been converted to a residence following its use as a school. In addition, the hazardous condition of the structure's interior is evident. Two ceilings which are visible in the photograph, (the upper, probably original plastered ceiling, and a secondary, adapted ceiling) as well as ceiling joists in the southernmost rooms have collapsed. Because of the dangerous condition of the interior of the building, additional interior photography was not attempted at this time. - Perry Township School No. 3, Middle Mount Vernon & Eickhoff Roads, Evansville, Vanderburgh County, IN

Late-Time Evolution of Composite Supernova Remnants: Deep Chandra Observations and Hydrodynamical Modeling of a Crushed Pulsar Wind Nebula in SNR G327.1-1.1

NASA Technical Reports Server (NTRS)

Temim, Tea; Slane, Patrick; Kolb, Christopher; Blondin, John; Hughes, John P.; Bucciantini, Niccolo

2015-01-01

In an effort to better understand the evolution of composite supernova remnants (SNRs) and the eventual fate of relativistic particles injected by their pulsars, we present a multifaceted investigation of the interaction between a pulsar wind nebula (PWN) and its host SNR G327.1-1.1. Our 350 ks Chandra X-ray observations of SNR G327.1-1.1 reveal a highly complex morphology; a cometary structure resembling a bow shock, prong-like features extending into large arcs in the SNR interior, and thermal emission from the SNR shell. Spectral analysis of the non-thermal emission offers clues about the origin of the PWN structures, while enhanced abundances in the PWN region provide evidence for mixing of supernova ejecta with PWN material. The overall morphology and spectral properties of the SNR suggest that the PWN has undergone an asymmetric interaction with the SNR reverse shock(RS) that can occur as a result of a density gradient in the ambient medium and or a moving pulsar that displaces the PWN from the center of the remnant. We present hydrodynamical simulations of G327.1-1.1 that show that its morphology and evolution can be described by a approx. 17,000 yr old composite SNR that expanded into a density gradient with an orientation perpendicular to the pulsar's motion. We also show that the RSPWN interaction scenario can reproduce the broadband spectrum of the PWN from radio to gamma-ray wavelengths. The analysis and modeling presented in this work have important implications for our general understanding of the structure and evolution of composite SNRs.

Tidal constraints on the interior of Venus

NASA Astrophysics Data System (ADS)

Dumoulin, C.; Tobie, G.; Verhoeven, O.; Rosenblatt, P.; Rambaux, N.

2017-06-01

As a prospective study for a future exploration of Venus, we compute the tidal response of Venus' interior assuming various mantle compositions and temperature profiles representative of different scenarios of Venus' formation and evolution. The mantle density and seismic velocities are modeled from thermodynamical equilibria of mantle minerals and used to predict the moment of inertia, Love numbers, and tide-induced phase lag characterizing the signature of the internal structure in the gravity field. The viscoelasticity of the mantle is parameterized using an Andrade rheology. From the models considered here, the moment of inertia lies in the range of 0.327 to 0.342, corresponding to a core radius of 2900 to 3450 km. Viscoelasticity of the mantle strongly increases the potential Love number relative to previously published elastic models. Due to the anelasticity effects, we show that the possibility of a completely solid metal core inside Venus cannot be ruled out based on the available estimate of k2 from the Magellan mission (Konopliv and Yoder, 1996). A Love number k2 lower than 0.27 would indicate the presence of a fully solid iron core, while for larger values, solutions with an entirely or partially liquid core are possible. Precise determination of the Love numbers, k2 and h2, together with an estimate of the tidal phase lag, are required to determine the state and size of the core, as well as the composition and viscosity of the mantle.

Tidal constraints on the interior of Venus

NASA Astrophysics Data System (ADS)

Dumoulin, C.; Tobie, G.; Verhoeven, O.; Rosenblatt, P.; Rambaux, N.

2017-12-01

As a prospective study for a future exploration of Venus, we compute the tidal response of Venus' interior assuming various mantle compositions and temperature profiles representative of different scenarios of Venus' formation and evolution. The mantle density and seismic velocities are modeled from thermodynamical equilibria of mantle minerals and used to predict the moment of inertia, Love numbers, and tide-induced phase lag characterizing the signature of the internal structure in the gravity field. The viscoelasticity of the mantle is parameterized using an Andrade rheology. From the models considered here, the moment of inertia lies in the range of 0.327 to 0.342, corresponding to a core radius of 2900 to 3450 km. Viscoelasticity of the mantle strongly increases the potential Love number relative to previously published elastic models. Due to the anelasticity effects, we show that the possibility of a completely solid metal core inside Venus cannot be ruled out based on the available estimate of k2 from the Magellan mission (Konopliv and Yoder, 1996). A Love number k2 lower than 0.27 would indicate the presence of a fully solid iron core, while for larger values, solutions with an entirely or partially liquid core are possible. Precise determination of the Love numbers, k2 and h2, together with an estimate of the tidal phase lag, are required to determine the state and size of the core, as well as the composition and viscosity of the mantle.

Preliminary Assessment of the Interior Noise Environment in the Large Civil Tiltrotor (LCTR2)

NASA Technical Reports Server (NTRS)

Grosveld, Ferdinand W.; Cabell, Randolph H.

2011-01-01

The second-generation Large Civil Tiltrotor (LCTR2) serves as a representative vehicle under the NASA Fundamental Aeronautics Program (FAP) Subsonic Rotary Wing (SRW) project with a design goal to transport 90 passengers over a distance of 1800 km at a speed of 550 km/hr. The tiltrotor combines the vertical lift capability of a helicopter with the speed, altitude, and range of a turboprop airplane. The blade-passage frequency of the four-bladed rotor is as low as 6.9 Hz during cruise conditions. The resulting low-frequency acoustic excitation and its harmonics, combined with the anticipated use of lightweight composite and sandwich materials for the fuselage sidewall, may pose a challenge to achieving acceptable interior noise levels. The objective of the present study is to perform a preliminary assessment of the expected interior noise environment in the LCTR2 cabin. The approach includes a combination of semi-empirical, analytical, and statistical energy analysis methods. Because the LCTR2 is a notional vehicle, the prediction approach was also applied to the XV-15 tiltrotor and Bombardier Q400 turobprop aircraft to compare predictions with publicly available experimental data. Guidance for the expected interior noise levels in the LCTR2 was obtained by considering both the predicted exterior noise levels and the transmission loss of a basic fuselage sidewall consisting of a skin, porous layer and a trim panel. Structural and acoustic resonances are expected to coincide with low order harmonics of the blade passage frequency. The estimated sound pressure levels in the LCTR2 may not be acceptable when evaluated against known characteristics of human response to low frequency sound.

Carbon Structural Investigations of Concentric Layers Within Macro-aggregates From Forest and Agricultural Soils

NASA Astrophysics Data System (ADS)

Dria, K. J.; Gamblin, D. E.; Smucker, A. J.; Park, E.; Filley, T. R.

2004-12-01

Much of the current research on the potential of agricultural and forest soils to act as sinks for greenhouse gases focuses on the capacity of the systems to form long-term stabilized fractions of soil organic matter (SOM). One proposed mechanism is that carbon is sequestered within soil aggregate interiors during the aggregation process. Repeated wetting-drying cycles change internal pore geometries and associated microhabitats and create more stable macro-aggregates. Research by Smucker and coworkers (EGU Abstracts, 2004) suggest that the exterior portions of aggregates contain greater concentrations of C and N than their interiors, establishing gradients of \\ä13C values across these aggregates. We present the results of a study to test if there exists molecular evidence of such gradients. Soil samples from forest, conventional tillage (CT) and no tillage (NT) agriculture ecosystems in Hoytville and Wooster LTER sites were gently sieved into various size fractions. Soil macro-aggregates (6.3-9.5mm) were peeled, by mechanical erosion chambers, into concentric layers and separated into exterior, transitional and interior regions. Alkaline CuO oxidation was used to determine the composition of lignin, suberin, and cutin biopolymers to determine changes in source and degradative states of SOM. Preliminary results indicate that both soils show similar relative yields of lignin and hydroxyl fatty acids with a greater abundance of lignin than cutin and suberin acids. Greater abundances (per 100mg organic carbon) of CuO products were observed in the native forest than in either agricultural system. The lignin in the NT agricultural soil was least oxidized, followed by the forest soils, then the CT agricultural soils. For both soils, slight trends in biopolymer concentrations were observed between the exterior, transitional and interior regions of the aggregates from the forest and CT or NT ecosystems.

Hyperdust : An advanced in-situ detection and chemical analysis of microparticles in space

NASA Astrophysics Data System (ADS)

Sternovsky, Z.; Gruen, E.; Horanyi, M.; Kempf, S.; Maute, K.; Srama, R.

2014-12-01

Interplanetary dust that originates from comets and asteroids may be in different stages of Solar System evolution. Atmosphereless planetary bodies, e.g., planetary satellites, asteroids, or Kuiper belt objects are enshrouded in clouds of dust released by meteoroid impacts or by volcanism. The ejecta grains are samples from the surface of these objects and their analysis can be performed from orbit or flyby to determine the surface composition, interior structure and ongoing geochemical processes. Early dust mass spectrometers on the Halley missions had sufficient mass resolution in order to provide important cosmochemical information in the near-comet high dust flux environment. The Ulysses dust detector discovered interstellar grains within the planetary system (Gruen et al. A&A, 1994) and its twin detector on Galileo discovered the tenuous dust clouds around the Galilean satellites (Krueger et al., Icarus, 2003). The similar-sized Cosmic Dust Analyzer onboard the Cassini mission combined a highly sensitive dust detector with a low-mass resolution mass spectrometer. Compositional dust measurements from this instrument probed the deep interior of Saturn's Enceladus satellite (Postberg et al., Nature, 2009). Based on this experience new instrumentation was developed that combined the best attributes of all these predecessors and exceeded their capabilities in accurate trajectory determination. The Hyperdust instrument is a combination of a Dust Trajectory Sensor (DTS) together with an analyzer for the chemical composition of dust particles in space. Dust particles' trajectories are determined by the measurement of induced electric signals. Large area chemical analyzers of 0.1 m2 sensitive area have been tested at a dust accelerator and it was demonstrated that they have sufficient mass resolution to resolve ions with atomic mass number >100. The Hyperdust instrument is capable of distinguishing interstellar and interplanetary grains based on their trajectory composition information. In orbit or flyby near airless planetary bodies the instrument can map the surface compositional down to a spatial resolution of ~10 km. The Hyperdust instrument is currently being developed to TRL 6 funded by NASA's MatISSE program to be a low-mass, high performance instrument for future in-situ exploration.

50. INTERIOR OF BRIDGE SUSPENSION STRUCTURE ABOVE BRIDGE NOS. 10 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

50. INTERIOR OF BRIDGE SUSPENSION STRUCTURE ABOVE BRIDGE NOS. 10 AND 9 SHOWING CABLE COUNTERWEIGHT SYSTEM AND SCREW-TYPE VERTICAL ADJUSTMENT MACHINERY (LIFTING SCREWS). LOOKING NORTH. - Greenville Yard, Transfer Bridge System, Port of New York/New Jersey, Upper New York Bay, Jersey City, Hudson County, NJ

5. Interior of second floor of Dixie Cotton Mill, view ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. Interior of second floor of Dixie Cotton Mill, view facing east. Again note the change in column type and roof structure from the 1913 addition (foreground) to a portion of the original 1895 structure (background). - Dixie Cotton Mill, 710 Greenville Street, La Grange, Troup County, GA

Interior Structure and Habitability of Ocean Worlds

NASA Astrophysics Data System (ADS)

Vance, S.; Bills, B. G.; Cammarano, F.; Panning, M. P.; Stähler, S. C.

2016-12-01

Earth's habitability depends critically on its interior structure and dynamics. Global redox cycles rely on Earth's mantle for continued flux of reduced materials (e.g., Hayes and Waldbauer 2006). Similarly, the habitability of ocean worlds must be understood in terms of their interior structure and evolution (Zolotov and Shock 2004, Hand et al. 2009, Nimmo and Pappalardo 2016, Vance et al. 2016). Combined seismology, gravity, and magnetic investigations may be able to distinguish between a hot active interior and a cold dead one. To evaluate such investigations, we are developing detailed models of interior density, elastic and anelastic structure, and associated seismic sources and signatures, building on prior work (Cammarano et al. 2006). We will present self-consistent 1-D structural models for ocean world interiors that use available thermodynamic data for fluids, ices, and rocks. Cammarano, F., V. Lekic, M. Manga, M. Panning, and B. Romanowicz (2006). Long-period seismology on Europa: 1. Physically consistent interior models. Journal of Geophysical Research, E12009:doi:10.1029/2006JE002710. Hand, K. P., C. Chyba, J. Priscu, R. Carlson, and K. Nealson (2009). Astrobiology and the Potential for Life on Europa, page 589. Arizona University Press. Hayes, J. M. and J. R. Waldbauer (2006). The carbon cycle and associated redox processes through time. Philosophical Transactions of the Royal Society B: Biological Sciences, 361(1470):931-950. Nimmo, F. and R. T. Pappalardo (2016). Ocean Worlds in the Outer Solar System. Journal of Geophysical Research, doi:10.1002/2016JE005081 Vance, S. D., K. P. Hand, and R. T. Pappalardo (2016). Geophysical controls of chemical disequilibria in Europa. Geophysical Research Letters, doi:10.1002/2016GL068547. Zolotov, M. Y. and E. L. Shock (2004). A model for low-temperature biogeochemistry of sulfur, carbon, and iron on Europa. Journal of Geophysical Research-Planets, 109(E6):E06003.

Using in-cell SHAPE-Seq and simulations to probe structure-function design principles of RNA transcriptional regulators.

PubMed

Takahashi, Melissa K; Watters, Kyle E; Gasper, Paul M; Abbott, Timothy R; Carlson, Paul D; Chen, Alan A; Lucks, Julius B

2016-06-01

Antisense RNA-mediated transcriptional regulators are powerful tools for controlling gene expression and creating synthetic gene networks. RNA transcriptional repressors derived from natural mechanisms called attenuators are particularly versatile, though their mechanistic complexity has made them difficult to engineer. Here we identify a new structure-function design principle for attenuators that enables the forward engineering of new RNA transcriptional repressors. Using in-cell SHAPE-Seq to characterize the structures of attenuator variants within Escherichia coli, we show that attenuator hairpins that facilitate interaction with antisense RNAs require interior loops for proper function. Molecular dynamics simulations of these attenuator variants suggest these interior loops impart structural flexibility. We further observe hairpin flexibility in the cellular structures of natural RNA mechanisms that use antisense RNA interactions to repress translation, confirming earlier results from in vitro studies. Finally, we design new transcriptional attenuators in silico using an interior loop as a structural requirement and show that they function as desired in vivo. This work establishes interior loops as an important structural element for designing synthetic RNA gene regulators. We anticipate that the coupling of experimental measurement of cellular RNA structure and function with computational modeling will enable rapid discovery of structure-function design principles for a diverse array of natural and synthetic RNA regulators. © 2016 Takahashi et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

The lunar interior

NASA Technical Reports Server (NTRS)

Anderson, D. L.; Kovach, R. L.

1972-01-01

The compressional velocities are estimated for materials in the lunar interior and compared with lunar seismic results. The lower crust has velocities appropriate for basalts or anorthosites. The high velocities associated with the uppermost mantle imply high densities and a change in composition to a lighter assemblage at depths of the order of 120 km. Calcium and aluminum are probably important components of the upper mantle and are deficient in the lower mantle. Much of the moon may have accreted from material similar in composition to eucrites. The important mineral of the upper mantle is garnet; possible accessory minerals are kyanite, spinel, and rutile. If the seismic results stand up, the high velocity layer in the moon is more likely to be a high pressure form of anorthosite than eclogite, pyroxenite, or dunite. The thickness of the layer is of the order of 50 km. Cosmic abundances can be maintained if the lower mantle is ferromagnesium silicate with minimal amounts of calcium and aluminum. Achondrites such as eucrites and howardites have more of the required characteristics of the lunar interior than carbonaceous chondrites. A density inversion in the moon is a strong possibility.

Active control of turbulent boundary layer sound transmission into a vehicle interior

NASA Astrophysics Data System (ADS)

Caiazzo, A.; Alujević, N.; Pluymers, B.; Desmet, W.

2016-09-01

In high speed automotive, aerospace, and railway transportation, the turbulent boundary layer (TBL) is one of the most important sources of interior noise. The stochastic pressure distribution associated with the turbulence is able to excite significantly structural vibration of vehicle exterior panels. They radiate sound into the vehicle through the interior panels. Therefore, the air flow noise becomes very influential when it comes to the noise vibration and harshness assessment of a vehicle, in particular at low frequencies. Normally, passive solutions, such as sound absorbing materials, are used for reducing the TBL-induced noise transmission into a vehicle interior, which generally improve the structure sound isolation performance. These can achieve excellent isolation performance at higher frequencies, but are unable to deal with the low-frequency interior noise components. In this paper, active control of TBL noise transmission through an acoustically coupled double panel system into a rectangular cavity is examined theoretically. The Corcos model of the TBL pressure distribution is used to model the disturbance. The disturbance is rejected by an active vibration isolation unit reacting between the exterior and the interior panels. Significant reductions of the low-frequency vibrations of the interior panel and the sound pressure in the cavity are observed.

Molecular dynamic simulations of the intergranular films between alumina and silicon nitride crystal grains

NASA Astrophysics Data System (ADS)

Zhang, Shenghong

The intergranular films (IGFs) between the ceramics grains have very important effects on the structure and mechanical properties on the whole ceramics and have been studied for many decades. In the thesis, molecular dynamic (MD) computer simulations were applied to study the IGFs between the alumina and silicon nitride ceramic grains. Preferential adsorption of specific ions from the IGFs to the contacting surfaces of the alumina crystals was observed in the study of calcium-alumino-silicate glassy (CAS) IGFs formed between the combined basal and prism orientations of alpha-Al2O3 crystals. This segregation of specific ions to the interface enables formation of localized, ordered structures between the IGF and the crystals. However, the segregation behavior of the ions is anisotropic, depending on the orientation of the alpha-Al2O 3 crystals. Self-diffusion of calcium ions between these CAS IGFs was also carried out by MD simulations. The results show that the diffusion coefficients adjacent to the interfaces are smaller and the activation energies are much higher than those in the interior of the IGF and in bulk glasses. It was also suggested that Ca transport is mainly though the interior of the IGF and implies that diffusion would be significantly inhibited by sufficiently thin IGFs. The growth of the alumina ceramic grains was simulated in the contacting with IGFs containing high concentrations of aluminum ions. Five different compositions in the IGFs were studied. Results show preferential growth along the [1120] of the (1120) surface in comparison to growth along the [0001] direction on the (0001) surface for compositions near a Ca/Al ratio of 0.5. The simulations also show the mechanism by which Ca ions in the IGF inhibit growth on the basal surface. The simulations provide an atomistic view of attachment onto crystal surfaces, affecting grain growth in alumina. The dissolution of the alumina crystal grains in the silicate melts is another important issue in the application of alumina ceramics. The simulations results showed that alumina grains dissolved into the melts homogeneously at very high temperatures. The orientation of the crystals and the compositions of the melts only take effect at some intermediate temperatures, to make the alumina grains dissolution anisotropic. The fracture phenomena of the pure silica IGFs between the basal silicon nitride crystals were studied by applying the constant tensile strain on the simulated IGF system, as well as for the bulk silica glass for the comparison. The data indicated that the fracture was happened in the interior of the IGFs and the thickness of the IGFs has important effect on the fracture stress/strain relationships.

Frequency-independent radiation modes of interior sound radiation: An analytical study

NASA Astrophysics Data System (ADS)

Hesse, C.; Vivar Perez, J. M.; Sinapius, M.

2017-03-01

Global active control methods of sound radiation into acoustic cavities necessitate the formulation of the interior sound field in terms of the surrounding structural velocity. This paper proposes an efficient approach to do this by presenting an analytical method to describe the radiation modes of interior sound radiation. The method requires no knowledge of the structural modal properties, which are often difficult to obtain in control applications. The procedure is exemplified for two generic systems of fluid-structure interaction, namely a rectangular plate coupled to a cuboid cavity and a hollow cylinder with the fluid in its enclosed cavity. The radiation modes are described as a subset of the acoustic eigenvectors on the structural-acoustic interface. For the two studied systems, they are therefore independent of frequency.

High Speed Research Program Structural Acoustics Multi-Year Summary Report

NASA Technical Reports Server (NTRS)

Beier, Theodor H.; Bhat, Waman V.; Rizzi, Stephen A.; Silcox, Richard J.; Simpson, Myles A.

2005-01-01

This report summarizes the work conducted by the Structural Acoustics Integrated Technology Development (ITD) Team under NASA's High Speed Research (HSR) Phase II program from 1993 to 1999. It is intended to serve as a reference for future researchers by documenting the results of the interior noise and sonic fatigue technology development activities conducted during this period. For interior noise, these activities included excitation modeling, structural acoustic response modeling, development of passive treatments and active controls, and prediction of interior noise. For sonic fatigue, these activities included loads prediction, materials characterization, sonic fatigue code development, development of response reduction techniques, and generation of sonic fatigue design requirements. Also included are lessons learned and recommendations for future work.

Propeller modelling effects on interior noise in cylindrical cavities with application to active control

NASA Technical Reports Server (NTRS)

Silcox, R. J.; Lester, H. C.

1989-01-01

The coupling of a vibrating finite elastic cylinder and its interior cavity, closed with rigid end caps, is examined. Results are presented for several types of excitation including a point force, a single external acoustic monopole, and an array of external monopoles. Modal spectra are examined for a frequency range typical of the harmonic noise produced by advanced turbo-props. The effect of frequency and source distribution on modal content is presented. Significant interface modal filtering, which would have a beneficial impact on an active system for reducing interior noise, was found to occur for all cases. Some preliminary experimental data for a stiffened, composite cylinder are presented and discussed.

Overall interior view of structures shop (11 shop) located on ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Overall interior view of structures shop (11 shop) located on west side of building 57 - looking north; the south end of the structures shop was devoted to welding heavy plate foundations and ship components; the floor is fabricated of case steel and features a grillwork of 1 1/2 fabricated holes which are used as sockets for gripping position pins. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Structure Shop, League Island, Philadelphia, Philadelphia County, PA

Neutron Star Astronomy in the era of the European Extremely Large Telescope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mignani, Roberto P.

About 25 isolated neutron stars (INSs) are now detected in the optical domain, mainly thanks to the HST and to VLT-class telescopes. The European Extremely Large Telescope(E-ELT) will yield {approx}100 new identifications, many of which from the follow-up of SKA, IXO, and Fermi observations. Moreover, the E-ELT will allow to carry out, on a much larger sample, INS observations which still challenge VLT-class telescopes, enabling studies on the structure and composition of the NS interior, of its atmosphere and magnetosphere, as well as to search for debris discs. In this contribution, I outline future perspectives for NS optical astronomy withmore » the E-ELT.« less

Neutrinos from Hell: the Dawn of Neutrino Geophysics

ScienceCinema

Gratta, Giorgio

2018-02-26

Seismic waves have been for long time the only messenger reporting on the conditions deep inside the Earth. While global seismology provides amazing details about the structure of our planet, it is only sensitive to the mechanical properties of rocks and not to their chemical composition. In the last 5 years KamLAND and Borexino have started measuring anti-neutrinos produced by Uranium and Thorium inside the Earth. Such "Geoneutrinos" double the number of tools available to study the Earth's interior, enabling a sort of global chemical analysis of the planet, albeit for two elements only. I will discuss the results of these new measurements and put them in the context of the Earth Sciences.

Europa's differentiated internal structure: inferences from four Galileo encounters.

PubMed

Anderson, J D; Schubert, G; Jacobson, R A; Lau, E L; Moore, W B; Sjogren, W L

1998-09-25

Radio Doppler data from four encounters of the Galileo spacecraft with the jovian moon Europa have been used to refine models of Europa's interior. Europa is most likely differentiated into a metallic core surrounded by a rock mantle and a water ice-liquid outer shell, but the data cannot eliminate the possibility of a uniform mixture of dense silicate and metal beneath the water ice-liquid shell. The size of a metallic core is uncertain because of its unknown composition, but it could be as large as about 50 percent of Europa's radius. The thickness of Europa's outer shell of water ice-liquid must lie in the range of about 80 to 170 kilometers.

The Saturn PRobe Interior and aTmosphere Explorer (SPRITE) Mission Concept

NASA Astrophysics Data System (ADS)

Atkinson, David H.; Simon, Amy; Banfield, Don

2017-04-01

The proposed NASA New Frontiers Saturn PRobe Interior and aTmosphere Explorer (SPRITE) mission would measure the abundance of helium and the other noble gases, elemental and isotopic abundances, the clouds, dynamics, and processes within Saturn's troposphere. In situ measurements of Saturn's atmosphere by SPRITE would provide a significantly improved context for understanding the results from the Galileo Jupiter probe, and the formation and evolution of the gas giant planets, resulting in a paradigm shift in our understanding of the formation, evolution, and ultimately the present day structure of the solar system. The proposed SPRITE concept carries an instrument payload to measure Saturn's atmospheric structure, dynamics, composition, chemistry, and clouds to at least 10 bars. A Quadrupole Mass Spectrometer measures noble gases and noble gas isotopes to accuracies that exceed the Galileo probe measurements at Jupiter and allows for discrimination between competing theories of giant planet formation, evolution, and possible migration. Of particular importance are measurements of helium, key to understanding Saturn's thermal evolution. A Tunable Laser Spectrometer measures molecular abundances and isotope ratios to determine the chemical structure of Saturn's atmosphere, and disequilibrium species such as PH3 and CO which can be used to predict Saturn's deep water abundance. An Atmospheric Structure Instrument provides the pressure/temperature profile of Saturn's atmosphere to determine the altitude profile of static stability, and when combined with cloud measurements from the SPRITE Nephelometer, would elucidate processes that determine the location and structure of Saturn's multiple cloud layers. Coupled with the measurement of atmospheric vertical velocities from the Atmospheric Structure Instrument, a Doppler Wind Experiment provides a measure of the 3-dimensional dynamics of the Saturn atmosphere, including the profile of zonal winds with depth and vertical motions from atmospheric waves. The proposed Science Objectives of the SPRITE mission are to: 1. Constrain competing models of habitable system formation and extent of migration in the early solar system by obtaining a chemical inventory of Saturn's troposphere, 2. Determine if Saturn's in situ atmosphere chemistry agrees with condensation models and remotely observed composition, 3. Constrain Saturn's helium depletion to reconcile observed temperatures with thermal evolution models. 4. Perform in situ characterization of Saturn's tropospheric cloud structure to provide the ground truth basis for cloud retrieval models, and 5. Determine Saturn's in situ 3-dimensional atmospheric dynamics along the probe descent path to inform global circulation and analytical models of the time-variable cloud top motions. To develop an improved understanding of the formation, evolution, and structure of the solar system, it is essential that the role played by the giant planets be well understood, and this cannot be accomplished without in situ measurements of the composition, structure, dynamics, and processes of Saturn's atmosphere. The proposed SPRITE mission would carry a suite of instruments specifically tailored to achieve the science objectives, to provide fundamental ground truth measurements for improved understanding of remote sensing measurements including from Cassini, and to understand the formation, evolution, and structure of the solar system as well as represent key ground truth for understanding exoplanets.

25 CFR 11.200 - What is the composition of the Court of Indian Offenses?

Code of Federal Regulations, 2013 CFR

2013-04-01

... 25 Indians 1 2013-04-01 2013-04-01 false What is the composition of the Court of Indian Offenses? 11.200 Section 11.200 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAW AND ORDER COURTS OF INDIAN OFFENSES AND LAW AND ORDER CODE Courts of Indian Offenses; Personnel; Administration...

25 CFR 11.200 - What is the composition of the Court of Indian Offenses?

Code of Federal Regulations, 2011 CFR

2011-04-01

... 25 Indians 1 2011-04-01 2011-04-01 false What is the composition of the Court of Indian Offenses? 11.200 Section 11.200 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAW AND ORDER COURTS OF INDIAN OFFENSES AND LAW AND ORDER CODE Courts of Indian Offenses; Personnel; Administration...

25 CFR 11.200 - What is the composition of the Court of Indian Offenses?

Code of Federal Regulations, 2012 CFR

2012-04-01

... 25 Indians 1 2012-04-01 2011-04-01 true What is the composition of the Court of Indian Offenses? 11.200 Section 11.200 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAW AND ORDER COURTS OF INDIAN OFFENSES AND LAW AND ORDER CODE Courts of Indian Offenses; Personnel; Administration...

25 CFR 11.200 - What is the composition of the Court of Indian Offenses?

Code of Federal Regulations, 2014 CFR

2014-04-01

... 25 Indians 1 2014-04-01 2014-04-01 false What is the composition of the Court of Indian Offenses? 11.200 Section 11.200 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAW AND ORDER COURTS OF INDIAN OFFENSES AND LAW AND ORDER CODE Courts of Indian Offenses; Personnel; Administration...

43 CFR 15.10 - Operation of watercraft.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Operation of watercraft. 15.10 Section 15.10 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15... or property, no anchor shall be cast or dragged in such a way as to damage any reef structure. ...

43 CFR 15.10 - Operation of watercraft.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Operation of watercraft. 15.10 Section 15.10 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15... or property, no anchor shall be cast or dragged in such a way as to damage any reef structure. ...

43 CFR 15.10 - Operation of watercraft.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Operation of watercraft. 15.10 Section 15.10 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15... or property, no anchor shall be cast or dragged in such a way as to damage any reef structure. ...

43 CFR 15.11 - Explosives and dangerous weapons.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Explosives and dangerous weapons. 15.11 Section 15.11 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE... other kind of weapon potentially harmful to the reef structure. The use of such weapons from beyond the...

43 CFR 15.11 - Explosives and dangerous weapons.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Explosives and dangerous weapons. 15.11 Section 15.11 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE... other kind of weapon potentially harmful to the reef structure. The use of such weapons from beyond the...

43 CFR 15.11 - Explosives and dangerous weapons.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Explosives and dangerous weapons. 15.11 Section 15.11 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE... other kind of weapon potentially harmful to the reef structure. The use of such weapons from beyond the...

43 CFR 15.11 - Explosives and dangerous weapons.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Explosives and dangerous weapons. 15.11 Section 15.11 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE... other kind of weapon potentially harmful to the reef structure. The use of such weapons from beyond the...

43 CFR 15.11 - Explosives and dangerous weapons.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Explosives and dangerous weapons. 15.11 Section 15.11 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE... other kind of weapon potentially harmful to the reef structure. The use of such weapons from beyond the...

43 CFR 15.10 - Operation of watercraft.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Operation of watercraft. 15.10 Section 15.10 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15... or property, no anchor shall be cast or dragged in such a way as to damage any reef structure. ...

43 CFR 15.10 - Operation of watercraft.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Operation of watercraft. 15.10 Section 15.10 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15... or property, no anchor shall be cast or dragged in such a way as to damage any reef structure. ...

Using in-cell SHAPE-Seq and simulations to probe structure–function design principles of RNA transcriptional regulators

PubMed Central

Takahashi, Melissa K.; Watters, Kyle E.; Gasper, Paul M.; Abbott, Timothy R.; Carlson, Paul D.; Chen, Alan A.

2016-01-01

Antisense RNA-mediated transcriptional regulators are powerful tools for controlling gene expression and creating synthetic gene networks. RNA transcriptional repressors derived from natural mechanisms called attenuators are particularly versatile, though their mechanistic complexity has made them difficult to engineer. Here we identify a new structure–function design principle for attenuators that enables the forward engineering of new RNA transcriptional repressors. Using in-cell SHAPE-Seq to characterize the structures of attenuator variants within Escherichia coli, we show that attenuator hairpins that facilitate interaction with antisense RNAs require interior loops for proper function. Molecular dynamics simulations of these attenuator variants suggest these interior loops impart structural flexibility. We further observe hairpin flexibility in the cellular structures of natural RNA mechanisms that use antisense RNA interactions to repress translation, confirming earlier results from in vitro studies. Finally, we design new transcriptional attenuators in silico using an interior loop as a structural requirement and show that they function as desired in vivo. This work establishes interior loops as an important structural element for designing synthetic RNA gene regulators. We anticipate that the coupling of experimental measurement of cellular RNA structure and function with computational modeling will enable rapid discovery of structure–function design principles for a diverse array of natural and synthetic RNA regulators. PMID:27103533

Transmission loss characteristics of aircraft sidewall systems to control cabin interior noise

NASA Astrophysics Data System (ADS)

Yesil, Oktay; Serati, Paul M.; Hofbeck, Eric V.; Glover, Billy M.

We have explored the possibility of using new, light weight, and acoustically effective materials on aircraft interiors to control noise. The sidewall system elements were evaluated for increased TL in the laboratory. Measured TL for a given configuration, relative to a baseline, was used as an indication of the TL change to be expected for modifications. Test data were in good agreement with the predicted levels. The TL contributions due to all sidewall components were important for interior cabin noise control. Polyimide foam insulation was inferior to fiberglass in the mid-frequency range; however, foam was a better performer at high frequencies. Fiberglass/polyimide foam composite blankets, with less weight, provided noise reductions similar to fiberglass. 'Premium' fiberglass was slightly better performer than the standard fiberglass. Solid fiberglass interior trim panel provided adequate noise performance. Production-type trim attachment design could be improved to control flanking path for sound transmission.

Cryomagmatism in the outer solar system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kargel, J.S.

1990-01-01

Assemblages of cryovolcanic, tectonic, and impact structures form varied landscapes quite alien in their collective expression. Many variables can affect the cryovolcanic style of a satellite but none more so than cryolava composition. The compositional variable is examined in considerable detail. Existing knowledge of phase equilibria and physical properties of cosmochemically relevant unary, binary, and multi-component chemical systems are summarized. Where published knowledge was found lacking, measurements of the physical chemistry of volatile mixtures are presented. Cryovolcanic landscapes are briefly toured, and knowledge of the physical chemistry of volatile mixtures is applied to problems of cryovolcanological interest. Aqueous cryolavas maymore » range in composition from salt-water brines to cryogenic ammonia-water-rich multi-components solutions possibly involving methanol, ammonium sulfide, alkali chlorides, and many other potential components. Cryomagmatic distillation can greatly accentuate the importance of trace and minor constituents of icy satellites. The viscosities, densities, and other physical properties of these liquids vary considerably and depend sensitively on their exact compositions. These properties affect everything from cryovolcanic eruptive styles and landforms, to the way cryovolcanic crusts respond to tectonic stress. It is believed that the compositional variable is directly or indirectly implicated in a wide varity of geomorphic aspects of contrast among the icy satellites. Thus, even though as yet any specific morphology can be attributed to a specific composition, there appears to be a powerful link between composition of the ices originally accreted by a satellite and its subsequent interior evolution and exterior geomorphic appearance.« less

Optomechanical stability design of space optical mapping camera

NASA Astrophysics Data System (ADS)

Li, Fuqiang; Cai, Weijun; Zhang, Fengqin; Li, Na; Fan, Junjie

2018-01-01

According to the interior orientation elements and imaging quality requirements of mapping application to mapping camera and combined with off-axis three-mirror anastigmat(TMA) system, high optomechanical stability design of a space optical mapping camera is introduced in this paper. The configuration is a coaxial TMA system used in off-axis situation. Firstly, the overall optical arrangement is described., and an overview of the optomechanical packaging is provided. Zerodurglass, carbon fiber composite and carbon-fiber reinforced silicon carbon (C/SiC) are widely used in the optomechanical structure, because their low coefficient of thermal expansion (CTE) can reduce the thermal sensitivity of the mirrors and focal plane. Flexible and unloading support are used in reflector and camera supporting structure. Epoxy structural adhesives is used for bonding optics to metal structure is also introduced in this paper. The primary mirror is mounted by means of three-point ball joint flexures system, which is attach to the back of the mirror. Then, In order to predict flexural displacements due to gravity, static finite element analysis (FEA) is performed on the primary mirror. The optical performance peak-to-valley (PV) and root-mean-square (RMS) wavefront errors are detected before and after assemble. Also, the dynamic finite element analysis(FEA) of the whole optical arrangement is carried out as to investigate the performance of optomechanical. Finally, in order to evaluate the stability of the design, the thermal vacuum test and vibration test are carried out and the Modulation Transfer Function (MTF) and elements of interior orientation are presented as the evaluation index. Before and after the thermal vacuum test and vibration test, the MTF, focal distance and position of the principal point of optical system are measured and the result is as expected.

The surface and interior of Venus

NASA Technical Reports Server (NTRS)

Masursky, H.; Kaula, W. M.; Russell, C. T.; Schubert, G.; Mcgill, G. E.; Pettengill, G. H.; Shapiro, I. I.; Phillips, R. J.

1977-01-01

The present knowledge of Venus is reviewed with discussions of the nature and history of both the surface, crust and interior. Instrumentation on board the Pioneer Venus Orbiter, including the radar mapper, radio tracking and the fluxgate magnetometer, is described. Topographic, geological, Bouguer gravity, magnetic, and crustal thickness maps will be constructed from Orbiter data. These maps should provide information on composition and thermal history, the major geological or geophysical provinces, the rate of past and present tectonic activity, and evidence of past or present MHD dynamos.

Discovering and measuring a layered Earth: A foundational laboratory for developing students' understanding of Earth's interior structure

NASA Astrophysics Data System (ADS)

Hubenthal, M.; Braile, L. W.; Olds, S. E.; Taber, J.

2010-12-01

Geophysics research is continuously revealing new insights about Earth’s interior structure. Before students can grasp theses new complexities, they first must internalize the 1st order layered structure of Earth and comprehend how seismology contributes to the development of such models. Earth structure is of course covered in most introductory geoscience courses, though all too often instruction of this content is limited to didactic methods that make little effort to inspire or engage the minds of students. In the process, students are expected to blindly accept our understanding of the unseen and abstract. Thus, it is not surprising then that many students can draw a layered Earth diagram, yet not know that knowledge of Earth’s interior is based on information from earthquakes. Cognitive learning theory would suggest that what has been missing from instruction of Earth structure is a feasible method to present students with seismic evidence in a manner that allows students to become minds-on with the content; discovering or dispelling the presence of a layered Earth for themselves. Recent advances in serving seismic data to a non-seismologist audience have made the development of such laboratory investigations possible. In this exercise students use an inquiry approach to examine seismic evidence and determine that the Earth cannot have a homogeneous composition. Further they use the data to estimate the dimensions of Earth’s outer core. To reach these conclusions, students are divided into two teams, theoreticians and seismologists, to test the simplest hypothesis for Earth's internal structure; a homogeneous Earth. The theoreticians create a scale model of a homogeneous Earth and predict when seismic waves should arrive at various points on the model. Simultaneously, seismologists interpret a seismic record section from a recent earthquake noting when seismic waves arrive at various points around Earth. The two groups of students then compare the modeled arrivals to the observed data, and when plotted, a notable discrepancy is found. To help interpret the implications of this anomaly the students transfer the data to a second scale model. By extrapolating their data for additional earthquakes students are able to define and measure a boundary for Earth’s outer core. After completing this exercise, not only do students have an understanding of how we know about the structure of Earth, students are more prepared to understand the basics of seismic tomography and the interpretation and limitations of tomographic models.

A full-spectrum analysis of high-speed train interior noise under multi-physical-field coupling excitations

NASA Astrophysics Data System (ADS)

Zheng, Xu; Hao, Zhiyong; Wang, Xu; Mao, Jie

2016-06-01

High-speed-railway-train interior noise at low, medium, and high frequencies could be simulated by finite element analysis (FEA) or boundary element analysis (BEA), hybrid finite element analysis-statistical energy analysis (FEA-SEA) and statistical energy analysis (SEA), respectively. First, a new method named statistical acoustic energy flow (SAEF) is proposed, which can be applied to the full-spectrum HST interior noise simulation (including low, medium, and high frequencies) with only one model. In an SAEF model, the corresponding multi-physical-field coupling excitations are firstly fully considered and coupled to excite the interior noise. The interior noise attenuated by sound insulation panels of carriage is simulated through modeling the inflow acoustic energy from the exterior excitations into the interior acoustic cavities. Rigid multi-body dynamics, fast multi-pole BEA, and large-eddy simulation with indirect boundary element analysis are first employed to extract the multi-physical-field excitations, which include the wheel-rail interaction forces/secondary suspension forces, the wheel-rail rolling noise, and aerodynamic noise, respectively. All the peak values and their frequency bands of the simulated acoustic excitations are validated with those from the noise source identification test. Besides, the measured equipment noise inside equipment compartment is used as one of the excitation sources which contribute to the interior noise. Second, a full-trimmed FE carriage model is firstly constructed, and the simulated modal shapes and frequencies agree well with the measured ones, which has validated the global FE carriage model as well as the local FE models of the aluminum alloy-trim composite panel. Thus, the sound transmission loss model of any composite panel has indirectly been validated. Finally, the SAEF model of the carriage is constructed based on the accurate FE model and stimulated by the multi-physical-field excitations. The results show that the trend of the simulated 1/3 octave band sound pressure spectrum agrees well with that of the on-site-measured one. The deviation between the simulated and measured overall sound pressure level (SPL) is 2.6 dB(A) and well controlled below the engineering tolerance limit, which has validated the SAEF model in the full-spectrum analysis of the high speed train interior noise.

Interior view, groundfloor room in southeast corner looking south. Masonry ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior view, ground-floor room in southeast corner looking south. Masonry groin and barrel vaulting was used throughout the building in attempt to fireproof the structure, a major advancement in the design of institutional structures during the second quarter of the nineteenth century. - U. S. Naval Asylum, Biddle Hall, Gray's Ferry Avenue, Philadelphia, Philadelphia County, PA

57. INTERIOR VIEW OF VAL BRIDGE STRUCTURE SHOWING LAUNCHING TUBE, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

57. INTERIOR VIEW OF VAL BRIDGE STRUCTURE SHOWING LAUNCHING TUBE, STAIRS AND PORTION OF LAUNCHING DECK. NOTE SUPPORT CARRIAGE ASSEMBLY IN DISTANCE. Date unknown, circa March 1948. (Original photograph in possession of Dave Willis, San Diego, California.) - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Interior of during demolition; the brick structure in the middle ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior of during demolition; the brick structure in the middle housed the electric motors that ran the rolling mill (the motor house and rolling mills date from the early twentieth century) - Bethlehem Steel Corporation, South Bethlehem Works, Rolling Mill, Along Lehigh River, North of Fourth Street, West of Minsi Trail Bridge, Bethlehem, Northampton County, PA

Foam composite structures. [for fire retardant airframe materials

NASA Technical Reports Server (NTRS)

Delano, C. B.; Milligan, R. J.

1976-01-01

The need to include fire resistant foams into state of the art aircraft interior paneling to increase passenger safety in aircraft fires was studied. Present efforts were directed toward mechanical and fire testing of panels with foam inclusions. Skinned foam filled honeycomb and PBI structural foams were the two constructions investigated with attention being directed toward weight/performance/cost trade-off. All of the new panels demonstrated improved performance in fire and some were lighter weight but not as strong as the presently used paneling. Continued efforts should result in improved paneling for passenger safety. In particular the simple partial filling (fire side) of state-of-the-art honeycomb with fire resistant foams with little sacrifice in weight would result in panels with increased fire resistance. More important may be the retarded rate of toxic gas evolution in the fire due to the protection of the honeycomb by the foam.

Hollow Few-Layer Graphene-Based Structures from Parafilm Waste for Flexible Transparent Supercapacitors and Oil Spill Cleanup.

PubMed

Nguyen, Duc Dung; Hsieh, Ping-Yen; Tsai, Meng-Ting; Lee, Chi-Young; Tai, Nyan-Hwa; To, Bao Dong; Vu, Duc Tu; Hsu, Chia Chen

2017-11-22

We report a versatile strategy to exploit parafilm waste as a carbon precursor for fabrication of freestanding, hollow few-layer graphene fiber mesh (HFGM) structures without use of any gaseous carriers/promoters via an annealing route. The freestanding HFGMs possess good mechanical flexibility, tailorable transparency, and high electrical conductivity, consequently qualifying them as promising electrochemical electrodes. Because of the hollow spaces, electrolyte ions can easily access into and contact with interior surfaces of the graphene fibers, accordingly increasing electrode/electrolyte interfacial area. As expected, solid-state supercapacitors based on the HFGMs exhibit a considerable enhancement in specific capacitance (20-30 fold) as compared to those employing chemical vapor deposition compact graphene films. Moreover, the parafilm waste is found to be beneficial for one-step fabrication of nanocarbon/few-layer graphene composite meshes with superior electrochemical performance, outstanding superhydrophobic property, good self-cleaning ability, and great promise for oil spill cleanup.

Physicochemical fingerprinting of thermal waters of Beira Interior region of Portugal.

PubMed

Araujo, A R T S; Sarraguça, M C; Ribeiro, M P; Coutinho, P

2017-06-01

Mineral natural waters and spas have been used for therapeutic purposes for centuries, with Portugal being a very rich country in thermal waters and spas that are mainly distributed by northern and central regions where Beira Interior region is located. The use of thermal waters for therapeutic purposes has always been aroused a continuous interest, being dependent on physicochemical fingerprinting of this type of waters the indication for a treatment in a specific pathological condition. In the present work, besides a literature review about the physicochemical composition of the thermal waters of the Beira Interior region and its therapeutic indications, it was carried out an exhaustive multivariate analysis-principal component analysis and cluster analysis-to assess the correlation between different physicochemical parameters and the therapeutic indications claims described for these spas and thermal waters. These statistical methods used for data analysis enables classification of thermal waters compositions into different groups, regarding to the different variable selected, making possible an interpretation of variables affecting water compositions. Actually, Monfortinho and Longroiva are clearly quite different of the others, and Cró and Fonte Santa de Almeida appear together in all analysis, suggesting a strong resemblance between these waters. Thereafter, the results obtained allow us to demonstrate the role of major components of the studied thermal waters on a particular therapeutic purpose/indication and hence based on compositional and physicochemical properties partially explain their therapeutic qualities and beneficial effects on human health. This classification agreed with the results obtained for the therapeutic indications approved by the Portuguese National Health Authority and proved to be a valuable tool for the regional typology of mineral medicinal waters, constituting an important guide of the therapeutic armamentarium for well and specific-oriented pathological disturbs.

The effect of alkaline treatment and fiber orientation on impact resistant of bio-composites Sansevieria trifasciata fiber/polypropylene as automotive components material

NASA Astrophysics Data System (ADS)

Shieddieque, Apang Djafar; Mardiyati, Suratman, Rochim; Widyanto, Bambang

2018-04-01

The increasing amount of car usage is causing an escalated amount of fuel consumption and CO2 emission. It implicates demand for the automotive industry to increase the efficiency of their products, One of the most effective ways to solve the issue is to find green weight light material for the interior automotive component. The Aim of this research was to investigate the effect of alkaline treatment and fiber orientation on the impact resistant of material bio- composite sansevieiria trifasciata fiber/Polypropylene. In this research, bio-composites sansevieria trifasciata fiber/Polypropylene was prepared with random fiber orientation and unidirectional orientation by using a hot press method with pressure 140 Bar and temperature 240°C. Fiber was taken from Sansevieria trifasciata by using mechanical retting. In this study, Sansevieria fiber was given alkaline treatment (mercerization) with NaOH 3% (w/w) solution at temperature 100°C for an hour. The fraction of fiber volume that were used in this experiment are 0%, 5%, 10%, and 15%. The impact test was conducted based on ASTM D 6110 - 04, and the fracture analysis was investigated by scanning electron microscope (SEM). The best result of impact toughness and fracture analysis were achieved by bio composite untreated and unidirectional sansevieria trifasciata fiber/Polypropylene with fiber volume fraction of 15%, which was 48.092kJ/m2 for impact resistant. As compared to the impact toughness standard, which needed for interior automotive component, the impact toughness of sansevieria trifasciata fiber/Polypropylene has fulfilled the standard of the interior material automotive industry. Therefore, this material can be potentially used as materials on the car exterior component.

New rain shed (Building No. 241) interior showing posts, braces, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

New rain shed (Building No. 241) interior showing posts, braces, and roof structure. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

A C8-Modified Graphene@mSiO2 Composites Based Method for Quantification of Gallic Acid in Rat Plasma after Oral Administration of Changtai Granule and Its Application to Pharmacokinetics.

PubMed

Xu, Chen; Yu, Yingjia; Ling, Li; Wang, Yang; Zhang, Jundong; Li, Yan; Duan, Gengli

2017-01-01

A rapid, effective extraction technique has been established for measuring the gallic acid in rat plasma by using sandwich-structured graphene/mesoporous silica composites with C 8 -modified interior pore-walls as adsorbent. The unique characteristics of the graphene-silica composites excluded large molecules, like proteins, from the mesopore channels as a result of size exclusion effect, leading to a direct extraction of drug molecules from protein-rich biological samples such as plasma without any other pretreatment procedure. Followed by elution and centrifugation, the gallic acid-absorbed composites were rapidly isolated before LC-MS/MS. Serving as a reliable tool for analysis of Traditional Chinese Medicine: Changtai Granule, the newly developed method was fully validated and successfully applied in the pharmacokinetic study of gallic acid in rat plasma. Extraction recovery, matrix effect and stability were satisfactory in rat plasma. According to the results of pharmacokinetic studies, Changtai Granule exhibited greater adsorption, distribution and clearance properties of gallic acid in the treatment of ulcerative colitis. Hence, this study may offer a valuable alternative to simplify and speed up sample preparation, and be useful for clinical studies of related preparations.

Density Of The Continental Roots: Compositional And Thermal Effects

NASA Astrophysics Data System (ADS)

Kaban, M. K.; Schwintzer, P.; Artemieva, I.; Mooney, W. D.

We use gravity, thermal, and seismic data to examine how the density and composi- tion of lithospheric roots vary beneath the cratons. Our interpretation is based on the gravity anomalies calculated by subtracting the gravitational effects of bathymetry, to- pography, and the crust from the observed gravity field, and the residual topography that characterizes the isostatic state of the lithosphere. We distinguish the effects of temperature and compositional variations in producing lithospheric density anomalies using two independent temperature constrains: based on interpretation of the surface heat flow data and estimated from global seismic tomography data. We find that in situ lithospheric density differs significantly between individual cratons, with the most dense values found beneath Eurasia and the least dense values beneath South Africa. This demonstrates that there is not a simple compensation of thermal and composition effects. We present a new gravity anomaly map that was corrected for crustal density structure and lithospheric temperatures. This map reveals differences in lithospheric composition, that are the result of the petrologic processes that have formed and mod- ified the lithosphere. All significant negative gravity anomalies are found in cratonic regions. In contrast, positive gravity anomalies are found in two distinct regions: near ocean-continent and continent-continent subduction zones, and within some continen- tal interiors. The origin of the latter positive anomalies is uncertain.

Discovering the interior of black holes

NASA Astrophysics Data System (ADS)

Brustein, Ram; Medved, A. J. M.; Yagi, K.

2017-12-01

The detection of gravitational waves (GWs) from black hole (BH) mergers provides an inroad toward probing the interior of astrophysical BHs. The general-relativistic description of the BH interior is that of empty spacetime with a (possibly) singular core. Recently, however, the hypothesis that the BH interior does not exist has been gaining traction, as it provides a means for resolving the BH information-loss problem. Here, we propose a simple method for answering the following question: Does the BH interior exist and, if so, does it contain some distribution of matter or is it mostly empty? Our proposal is premised on the idea that, similar to the case of relativistic, ultracompact stars, any BH-like object whose interior has some matter distribution should support fluid modes in addition to the conventional spacetime modes. In particular, the Coriolis-induced Rossby (r-) modes, whose spectrum is mostly insensitive to the composition of the interior matter, should be a universal feature of such BH-like objects. In fact, the frequency and damping time of these modes are determined by only the object's mass and speed of rotation. The r-modes oscillate at a lower frequency, decay at a slower rate, and produce weaker GWs than do the spacetime modes. Hence, they imprint a model-insensitive signature of a nonempty interior in the GW spectrum resulting from a BH merger. We find that future GW detectors, such as Advanced LIGO with its design sensitivity, have the potential of detecting such r-modes if the amount of GWs leaking out quantum mechanically from the interior of a BH-like object is sufficiently large.

Microfossils in Carbonaceous Meteorites

NASA Technical Reports Server (NTRS)

Hoover, Richard B.

2009-01-01

Microfossils of large filamentous trichomic prokaryotes have been detected during in-situ investigations of carbonaceous meteorites. This research has been carried out using the Field Emission Scanning Electron Microscope (FESEM) to examine freshly fractured interior surfaces of the meteorites. The images obtained reveal that many of these remains are embedded in the meteorite rock matrix. Energy Dispersive X-Ray Spectroscopy (EDS) studies establish that the filamentous microstructures have elemental compositions consistent with the meteorite matrix, but are often encased within carbon-rich electron transparent sheath-like structures infilled with magnesium sulfate. This is consistent with the taphonomic modes of fossilization of cyanobacteria and sulphur bacteria, since the life habits and processes of these microorganisms frequently result in distinctive chemical biosignatures associated with the properties of their cell-walls, trichomes, and the extracellular polymeric substances (EPS) of the sheath. In this paper the evidence for biogenicity presented includes detailed morphological and morphometric data consistent with known characteristics of uniseriate and multiseriate cyanobacteria. Evidence for indigeneity includes the embedded nature of the fossils and elemental compositions inconsistent with modern biocontaminants.

Neutron star Interior Composition Explorer (NICER)

NASA Image and Video Library

2017-12-08

Optics Lead Takashi Okajima prepares to align NICER’s X-ray optics. The payload’s 56 mirror assemblies concentrate X-rays onto silicon detectors to gather data that will probe the interior makeup of neutron stars, including those that appear to flash regularly, called pulsars. The Neutron star Interior Composition Explorer (NICER) is a NASA Explorer Mission of Opportunity dedicated to studying the extraordinary environments — strong gravity, ultra-dense matter, and the most powerful magnetic fields in the universe — embodied by neutron stars. An attached payload aboard the International Space Station, NICER will deploy an instrument with unique capabilities for timing and spectroscopy of fast X-ray brightness fluctuations. The embedded Station Explorer for X-ray Timing and Navigation Technology demonstration (SEXTANT) will use NICER data to validate, for the first time in space, technology that exploits pulsars as natural navigation beacons. Credit: NASA/Goddard/ Keith Gendreau NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Passive interior noise reduction analysis of King Air 350 turboprop aircraft using boundary element method/finite element method (BEM/FEM)

NASA Astrophysics Data System (ADS)

Dandaroy, Indranil; Vondracek, Joseph; Hund, Ron; Hartley, Dayton

2005-09-01

The objective of this study was to develop a vibro-acoustic computational model of the Raytheon King Air 350 turboprop aircraft with an intent to reduce propfan noise in the cabin. To develop the baseline analysis, an acoustic cavity model of the aircraft interior and a structural dynamics model of the aircraft fuselage were created. The acoustic model was an indirect boundary element method representation using SYSNOISE, while the structural model was a finite-element method normal modes representation in NASTRAN and subsequently imported to SYSNOISE. In the acoustic model, the fan excitation sources were represented employing the Ffowcs Williams-Hawkings equation. The acoustic and the structural models were fully coupled in SYSNOISE and solved to yield the baseline response of acoustic pressure in the aircraft interior and vibration on the aircraft structure due to fan noise. Various vibration absorbers, tuned to fundamental blade passage tone (100 Hz) and its first harmonic (200 Hz), were applied to the structural model to study their effect on cabin noise reduction. Parametric studies were performed to optimize the number and location of these passive devices. Effects of synchrophasing and absorptive noise treatments applied to the aircraft interior were also investigated for noise reduction.

Pioneer 11's New Saturn.

ERIC Educational Resources Information Center

Science News, 1979

1979-01-01

New findings about the planet, Saturn and its environs, as collected by Pioneer 11 are detailed. Topics discussed include: the composition of the planet's interior, the search for new satellites, and the planet's magnetic field. (BT)

Tidal constraints on the interior of Venus

NASA Astrophysics Data System (ADS)

Dumoulin, Caroline; Tobie, Gabriel; Verhoeven, Olivier; Rosenblatt, Pascal; Rambaux, Nicolas

2017-04-01

As a prospective study for a future exploration of Venus, we compute the tidal response of Venus' interior assuming various mantle compositions and temperature profiles representative of different scenarios of Venus' formation and evolution. The mantle density and seismic velocities are modeled from thermodynamical equilibria of mantle minerals and used to predict the moment of inertia, Love numbers and tidal lag characterizing the signature of the internal structure in the gravity field. The viscoelasticity of the mantle is parameterized using an Andrade rheology. From the models considered here, the moment of inertia lies in the range of 0.327 to 0.342, corresponding to a core radius of 2900 to 3450 km. The potential Love number, k2, varies from 0.25 to 0.36. Viscoelasticity of the mantle strongly increases the Love number relative to previous elastic models : depending on mantle viscosity, k2 is increased by up to 25% using a liquid core. Moreover, once a viscoelastic rheology is assumed for the core, our calculations show that the estimation of k2 from tracking of Magellan and Pioneer Venus Orbiter does not rule out the possibility of a completely solid core. Except if the solid core has a high viscosity (≥ 1018 Pa.s), solutions with both liquid and solid cores are consistent with the present-day estimation of k2. More accurate estimation of the Love number together with estimation of tidal lag by future exploration mission are required to determine the state of Venus' core and to constrain the thermo-compositional evolution of the mantle.

Longevity of Compositionally Stratified Layers in Ice Giants

NASA Astrophysics Data System (ADS)

Friedson, A. J.

2017-12-01

In the hydrogen-rich atmospheres of gas giants, a decrease with radius in the mixing ratio of a heavy species (e.g. He, CH4, H2O) has the potential to produce a density stratification that is convectively stable if the heavy species is sufficiently abundant. Formation of stable layers in the interiors of these planets has important implications for their internal structure, chemical mixing, dynamics, and thermal evolution, since vertical transport of heat and constituents in such layers is greatly reduced in comparison to that in convecting layers. Various processes have been suggested for creating compositionally stratified layers. In the interiors of Jupiter and Saturn, these include phase separation of He from metallic hydrogen and dissolution of dense core material into the surrounding metallic-H envelope. Condensation of methane and water has been proposed as a mechanism for producing stable zones in the atmospheres of Saturn and the ice giants. However, if a stably stratified layer is formed adjacent to an active region of convection, it may be susceptible to progressive erosion as the convection intrudes and entrains fluid into the unstable envelope. We discuss the principal factors that control the rate of entrainment and associated erosion and present a specific example concerning the longevity of stable layers formed by condensation of methane and water in Uranus and Neptune. We also consider whether the temporal variability of such layers may engender episodic behavior in the release of the internal heat of these planets. This research is supported by a grant from the NASA Solar System Workings Program.

High-mass twins & resolution of the reconfinement, masquerade and hyperon puzzles of compact star interiors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blaschke, David; Instytut Fizyki Teoretycznej, Uniwersytet Wroclawski, 50-204 Wroclaw; Alvarez-Castillo, David E.

2016-01-22

We aim at contributing to the resolution of three of the fundamental puzzles related to the still unsolved problem of the structure of the dense core of compact stars (CS): (i) the hyperon puzzle: how to reconcile pulsar masses of 2 M{sub ⊙} with the hyperon softening of the equation of state (EoS); (ii) the masquerade problem: modern EoS for cold, high density hadronic and quark matter are almost identical; and (iii) the reconfinement puzzle: what to do when after a deconfinement transition the hadronic EoS becomes favorable again? We show that taking into account the compositeness of baryons (bymore » excluded volume and/or quark Pauli blocking) on the hadronic side and confining and stiffening effects on the quark matter side results in an early phase transition to quark matter with sufficient stiffening at high densities which removes all three present-day puzzles of CS interiors. Moreover, in this new class of EoS for hybrid CS falls the interesting case of a strong first order phase transition which results in the observable high mass twin star phenomenon, an astrophysical observation of a critical endpoint in the QCD phase diagram.« less

Analytical study of interior noise control by fuselage design techniques on high-speed, propeller-driven aircraft

NASA Technical Reports Server (NTRS)

Revell, J. D.; Balena, F. J.; Koval, L. R.

1980-01-01

The acoustical treatment mass penalties required to achieve an interior noise level of 80 dBA for high speed, fuel efficient propfan-powered aircraft are determined. The prediction method used is based on theory developed for the outer shell dynamics, and a modified approach for add-on noise control element performance. The present synthesis of these methods is supported by experimental data. Three different sized aircraft are studied, including a widebody, a narrowbody and a business sized aircraft. Noise control penalties are calculated for each aircraft for two kinds of noise control designs: add-on designs, where the outer wall structure cannot be changed, and advanced designs where the outer wall stiffness level and the materials usage can be altered. For the add-on designs, the mass penalties range from 1.7 to 2.4 percent of the takeoff gross weight (TOGW) of the various aircraft, similar to preliminary estimates. Results for advanced designs show significant reductions of the mass penalties. For the advanced aluminum designs the penalties are 1.5% of TOGW, and for an all composite aircraft the penalties range from 0.74 to 1.4% of TOGW.

KSC-05PD-0013

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. The Deep Impact spacecraft is lifted from its transporter into the mobile service tower on Launch Pad 17-B at Cape Canaveral Air Force Station, Fla. the spacecraft will be attached to the second stage of the Boeing Delta II rocket. Next the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0010

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. At Astrotech Space Operations in Titusville, Fla., the Deep Impact spacecraft is secure in the canister for its move to Launch Pad 17-B on Cape Canaveral Air Force Station, Fla. Then, in the mobile service tower, the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0012

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. The Deep Impact spacecraft arrives before dawn at the mobile service tower on Launch Pad 17-B at Cape Canaveral Air Force Station, Fla. The spacecraft will be attached to the second stage of the Boeing Delta II rocket. Next the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0017

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. In the mobile service tower on Launch Pad 17-B at Cape Canaveral Air Force Station, Fla., workers stand by as the canister is lifted away from the Deep Impact spacecraft. Next the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0018

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. In the mobile service tower on Launch Pad 17-B at Cape Canaveral Air Force Station, Fla., workers watch as the protective cover surrounding the Deep Impact spacecraft is lifted away. Next the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0015

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. In the mobile service tower on Launch Pad 17-B at Cape Canaveral Air Force Station, Fla., workers begin lowering the Deep Impact spacecraft toward the second stage of the Boeing Delta II launch vehicle below for mating. Next the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0016

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. In the mobile service tower on Launch Pad 17-B at Cape Canaveral Air Force Station, Fla., workers attach the third stage motor, connected to the Deep Impact spacecraft, to the spin table on the second stage of the Boeing Delta II launch vehicle below. Next the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0014

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. The Deep Impact spacecraft is lifted into the top of the mobile service tower on Launch Pad 17-B at Cape Canaveral Air Force Station, Fla. the spacecraft will be attached to the second stage of the Boeing Delta II rocket. Next the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

A hybrid SEA/modal technique for modeling structural-acoustic interior noise in rotorcraft.

PubMed

Jayachandran, V; Bonilha, M W

2003-03-01

This paper describes a hybrid technique that combines Statistical Energy Analysis (SEA) predictions for structural vibration with acoustic modal summation techniques to predict interior noise levels in rotorcraft. The method was applied for predicting the sound field inside a mock-up of the interior panel system of the Sikorsky S-92 helicopter. The vibration amplitudes of the frame and panel systems were predicted using a detailed SEA model and these were used as inputs to the model of the interior acoustic space. The spatial distribution of the vibration field on individual panels, and their coupling to the acoustic space were modeled using stochastic techniques. Leakage and nonresonant transmission components were accounted for using space-averaged values obtained from a SEA model of the complete structural-acoustic system. Since the cabin geometry was quite simple, the modeling of the interior acoustic space was performed using a standard modal summation technique. Sound pressure levels predicted by this approach at specific microphone locations were compared with measured data. Agreement within 3 dB in one-third octave bands above 40 Hz was observed. A large discrepancy in the one-third octave band in which the first acoustic mode is resonant (31.5 Hz) was observed. Reasons for such a discrepancy are discussed in the paper. The developed technique provides a method for modeling helicopter cabin interior noise in the frequency mid-range where neither FEA nor SEA is individually effective or accurate.

Mass transfer in the Earth's interior: fluid-melt interaction in aluminosilicate-C-O-H-N systems at high pressure and temperature under oxidizing conditions

NASA Astrophysics Data System (ADS)

Mysen, Bjorn

2018-12-01

Understanding what governs the speciation in the C-O-H-N system aids our knowledge of how volatiles affect mass transfer processes in the Earth's interior. Experiments with aluminosilicate melt + C-O-H-N volatiles were, therefore, carried out with Raman and infrared spectroscopy to 800 °C and near 700 MPa in situ in hydrothermal diamond anvil cells. The measurements were conducted in situ with the samples at the desired temperatures and pressures in order to avoid possible structural and compositional changes resulting from quenching to ambient conditions prior to analysis. Experiments were conducted without any reducing agent and with volatiles added as H2O, CO2, and N2 because both carbon and nitrogen can occur in different oxidation states. Volatiles dissolved in melt comprise H2O, CO3 2-, HCO3 -, and molecular N2, whereas in the coexisting fluid, the species are H2O, CO2, CO3 2-, and N2. The HCO3 -/CO3 2- equilibrium in melts shift toward CO3 2- groups with increasing temperature with ΔH = 114 ± 22 kJ/mol. In fluids, the CO2 abundance is essentially invariant with temperature and pressure. For fluid/melt partitioning, those of H2O and N2 are greater than 1 with temperature-dependence that yields ΔH values of - 6.5 ± 1.5 and - 19.6 ± 3.7 kJ/mol, respectively. Carbonate groups, CO3 2- are favored by melt over fluid. Where redox conditions in the Earth's interior exceed that near the QFM oxygen buffer (between NNO and MW buffers), N2 is the stable nitrogen species and as such acts as a diluent of both fluids and melts. For fluids, this lower silicate solubility, in turn, enhances alkalinity. This means that in such environments, the transport of components such as high field strength cations, will be enhanced. Effects of dissolved N2 on melt structure are considerably less than on fluid structure.[Figure not available: see fulltext.

Vital Signs: Seismology of Europa and Other Ocean World

NASA Astrophysics Data System (ADS)

Kedar, S.; Vance, S.; Anandakrishnan, S.; Banerdt, W. B.; Bills, B. G.; Castillo, J. C.; Huang, H. H.; Jackson, J. M.; Lognonne, P. H.; Lorenz, R. D.; Panning, M. P.; Pike, W. T.; Stähler, S. C.; Tsai, V. C.

2016-12-01

Seismic investigations offer the most comprehensive view into the deep interiors of planetary bodies. The InSight mission and concepts for a Europa Lander and a Lunar Geophysical Network present unique opportunies for seismology to play a critical role in constraining interior structure and thermal state. In oceanic icy worlds, measuring the radial depths of compositional interfaces using seismology in a broad frequency range can sharpen inferences of interior structures deduced from gravity and magnetometry studies, such as those planned for NASA's proposed Europa Mission and ESA's JUICE mission. Seismology may also offer information about fluid motions within or beneath ice, which complements magnetic studies; and can record the dynamics of ice layers, which would reveal mechanisms and spatiotemporal occurrence of crack formation and propagation. Investigating these structures and processes in the future calls for detailed modeling of seismic sources and signatures, in order to develop the most suitable instrumentation. We will present results of simulations of plausible seismic sources and wave-field propagation in Europa, with extension to other oceanic icy worlds, building on prior studies (Kovach and Chyba 2001, Lee et al. 2003, Cammarano et al. 2006, Panning et al. 2006, Leighton et al. 2008). We also consider additional sources: gravitationally forced librations, which will create volume-filling turbulent flow, a possible seismic source similar to that seen from turbulent flow in terrestrial rivers; downflow of dense brines from chaos regions on Europa into its underlying ocean, which possibly resemble riverine flows and flows through glacial channels and ocean acoustic signals that couple with the overlying ice to produce seismic waves, by analogy with Earth's ocean-generated seismic hum. Cammarano, F., Lekic, V., Manga, M., Panning, M., and Romanowicz, B. (2006). JGR, E12009:doi:10.1029/2006JE002710. Kovach, R. L. and Chyba, C. F. (2001). Icarus, 150(2):279-287. Lee, S. W., Zanolin, M., Thode, A. M., Pappalardo, R. T., and Makris, N. C. (2003). Icarus, 165(1):144-167. Leighton, T. G., Finfer, D. C., and White, P. R. (2008). Icarus, 193(2):649-652. Panning, M., Lekic, V., Manga, M., and Romanowicz, B. (2006). Journal of Geophysical Research, E12008:doi:10.1029/2006JE002712.

Methods, Systems and Apparatuses for Radio Frequency Identification

NASA Technical Reports Server (NTRS)

Fink, Patrick W. (Inventor); Chu, Andrew W. (Inventor); Lin, Gregory Y. (Inventor); Kennedy, Timothy F. (Inventor); Ngo, Phong H. (Inventor); Brown, Dewey T. (Inventor); Byerly, Diane (Inventor)

2016-01-01

A system for radio frequency identification (RFID) includes an enclosure defining an interior region interior to the enclosure, and a feed for generating an electromagnetic field in the interior region in response to a signal received from an RFID reader via a radio frequency (RF) transmission line and, in response to the electromagnetic field, receiving a signal from an RFID sensor attached to an item in the interior region. The structure of the enclosure may be conductive and may include a metamaterial portion, an electromagnetically absorbing portion, or a wall extending in the interior region. Related apparatuses and methods for performing RFID are provided.

Methods, Systems and Apparatuses for Radio Frequency Identification

NASA Technical Reports Server (NTRS)

Fink, Patrick W. (Inventor); Chu, Andrew W. (Inventor); Lin, Gregory Y. (Inventor); Kennedy, Timothy F. (Inventor); Ngo, Phong H. (Inventor); Brown, Dewey T. (Inventor); Byerly, Diane (Inventor); Boose, Haley C. (Inventor)

2015-01-01

A system for radio frequency identification (RFID) includes an enclosure defining an interior region interior to the enclosure, and a feed for generating an electromagnetic field in the interior region in response to a signal received from an RFID reader via a radio frequency (RF) transmission line and, in response to the electromagnetic field, receiving a signal from an RFID sensor attached to an item in the interior region. The structure of the enclosure may be conductive and may include a metamaterial portion, an electromagnetically absorbing portion, or a wall extending in the interior region. Related apparatuses and methods for performing RFID are provided.

Methods, Systems and Apparatuses for Radio Frequency Identification

NASA Technical Reports Server (NTRS)

Brown, Dewey T. (Inventor); Lin, Gregory Y. (Inventor); Kennedy, Timothy F. (Inventor); Byerly, Diane (Inventor); Fink, Patrick W. (Inventor); Chu, Andrew W. (Inventor); Ngo, Phong H. (Inventor)

2017-01-01

A system for radio frequency identification (RFID) includes an enclosure defining an interior region interior to the enclosure, and a feed for generating an electromagnetic field in the interior region in response to a signal received from an RFID reader via a radio frequency (RF) transmission line and, in response to the electromagnetic field, receiving a signal from an RFID sensor attached to an item in the interior region. The structure of the enclosure may be conductive and may include a metamaterial portion, an electromagnetically absorbing portion, or a wall extending in the interior region. Related apparatuses and methods for performing RFID are provided.

A feature refinement approach for statistical interior CT reconstruction

NASA Astrophysics Data System (ADS)

Hu, Zhanli; Zhang, Yunwan; Liu, Jianbo; Ma, Jianhua; Zheng, Hairong; Liang, Dong

2016-07-01

Interior tomography is clinically desired to reduce the radiation dose rendered to patients. In this work, a new statistical interior tomography approach for computed tomography is proposed. The developed design focuses on taking into account the statistical nature of local projection data and recovering fine structures which are lost in the conventional total-variation (TV)—minimization reconstruction. The proposed method falls within the compressed sensing framework of TV minimization, which only assumes that the interior ROI is piecewise constant or polynomial and does not need any additional prior knowledge. To integrate the statistical distribution property of projection data, the objective function is built under the criteria of penalized weighed least-square (PWLS-TV). In the implementation of the proposed method, the interior projection extrapolation based FBP reconstruction is first used as the initial guess to mitigate truncation artifacts and also provide an extended field-of-view. Moreover, an interior feature refinement step, as an important processing operation is performed after each iteration of PWLS-TV to recover the desired structure information which is lost during the TV minimization. Here, a feature descriptor is specifically designed and employed to distinguish structure from noise and noise-like artifacts. A modified steepest descent algorithm is adopted to minimize the associated objective function. The proposed method is applied to both digital phantom and in vivo Micro-CT datasets, and compared to FBP, ART-TV and PWLS-TV. The reconstruction results demonstrate that the proposed method performs better than other conventional methods in suppressing noise, reducing truncated and streak artifacts, and preserving features. The proposed approach demonstrates its potential usefulness for feature preservation of interior tomography under truncated projection measurements.

A feature refinement approach for statistical interior CT reconstruction.

PubMed

Hu, Zhanli; Zhang, Yunwan; Liu, Jianbo; Ma, Jianhua; Zheng, Hairong; Liang, Dong

2016-07-21

Interior tomography is clinically desired to reduce the radiation dose rendered to patients. In this work, a new statistical interior tomography approach for computed tomography is proposed. The developed design focuses on taking into account the statistical nature of local projection data and recovering fine structures which are lost in the conventional total-variation (TV)-minimization reconstruction. The proposed method falls within the compressed sensing framework of TV minimization, which only assumes that the interior ROI is piecewise constant or polynomial and does not need any additional prior knowledge. To integrate the statistical distribution property of projection data, the objective function is built under the criteria of penalized weighed least-square (PWLS-TV). In the implementation of the proposed method, the interior projection extrapolation based FBP reconstruction is first used as the initial guess to mitigate truncation artifacts and also provide an extended field-of-view. Moreover, an interior feature refinement step, as an important processing operation is performed after each iteration of PWLS-TV to recover the desired structure information which is lost during the TV minimization. Here, a feature descriptor is specifically designed and employed to distinguish structure from noise and noise-like artifacts. A modified steepest descent algorithm is adopted to minimize the associated objective function. The proposed method is applied to both digital phantom and in vivo Micro-CT datasets, and compared to FBP, ART-TV and PWLS-TV. The reconstruction results demonstrate that the proposed method performs better than other conventional methods in suppressing noise, reducing truncated and streak artifacts, and preserving features. The proposed approach demonstrates its potential usefulness for feature preservation of interior tomography under truncated projection measurements.

On the spottedness, magnetism and internal structure of stars

NASA Astrophysics Data System (ADS)

Gershberg, R. E.

Kinematical structures within stellar interiors that are the result of a self-organization of these interiors as thermodynamically open nonlinear systems are proposed as the physical basis for stellar magnetism. It is noted that the ubiquitousness of stellar magnetism that follows from the hypothesis is not in contradiction with observations. These kinematical structures may be energy reservoirs, and changes in these structures may be connected with variations of an energy flux emergent from a stellar surface, while its internal energy sources remain constant, explaining the radiation deficit from sunspots and starspots.

Deep Interior: Probing the Structure of Primitive Bodies

NASA Astrophysics Data System (ADS)

Asphaug, Erik; Scheeres, Daniel; Safaeinili, Ali

Deep Interior is a mature Discovery-class mission concept focused on probing the geophysical behavior of primitive bodies, from the mechanics of their exterior materials to the structures of their interiors. Its theme is to discover how small bodies work - to learn the natural origin and evolution of asteroids, comets and other primitive bodies through radar reflection tomography and through detailed observations of the local and global effects of cratering. Learning the structure and mechanical response of asteroids and comets is also a precursor to resource utilization and hazardous asteroid mitigation. Overall the mission is aligned with NASA strategic sub-goal 3C, to advance scientific knowledge of the origin and history of the solar system ... and the hazards and resources present as humans explore space. Deep Interior deploys no complex landers or sub-spacecraft; the scientific instruments are a radar and a camera. A blast cratering experiments triggered by grenades leads to a low cost seismological investigation which complements the radar investigation. A desired addition is an imaging spectrometer. The science instruments are high heritage, as are the navigation techniques for orbiting and station-keeping. The mission conducts the following investigations at one or more asteroids: Radar Reflection Tomography (RRT). The first science phase is to operate a penetrating radar during each several-month rendezvous, deployed in reflection mode in the manner of ongoing radar investigations underway by Mars Express, Mars Reconnaissance Orbiter, and Kaguya. The RRT technique (Safaeinili et al., MAPS 2002) is analogous to performing a "CAT scan" from orbit: closely sampled radar echoes are processed to yield volumetric maps of mechanical and compositional boundaries, and to measure interior dielectric properties. Deep Interior utilizes a polar orbit (or station keeping) while the asteroid spins underneath; the result is to "peel the apple" with thousands of unique radar returns, providing global interior coverage. Camera images allow for the accurate reconstruction of spacecraft position at each radar acquisition. Radar flight heritage has been demonstrated by the MARSIS radar on Mars Express (Picardi et al., Science 2005; Plaut et al., Science 2007), the SHARAD radar onboard the Mars Reconnaissance Orbiter (Seu et al., JGR 2007), and the LRS radar onboard Kaguya (Ono et al, EPS 2007). The Mars radars have discovered detailed subsurface structure to km depths in a variety of terrains; early results from Kaguya demonstrate its ability to detect structure to km depths in basaltic materials on the Moon. A reflection radar deployed in orbit about a primitive body will enjoy significant simplifying benefits compared to using the same instrument for Mars or lunar radar science: (1) The proximity of operations leads to a much higher signal to noise, +30 dB or more. (2) The lack of an ionosphere makes for far simpler data modeling and analysis, compared with what is being required at Mars. (3) The body is globally illuminated during every data acquisition and since the final processing is a fully coherent focused processing based on all available observations, it will remove any "clutter" ambiguities. Laboratory measurements of dielectric properties for a suite of meteorite materials (Heggy et al., LPSC 2007) show that a 10 MHz radar can penetrate a chondritic asteroid up to 5 km diameter, and a 100 MHz radar can penetrate a chondritic asteroid up to 1 km diameter. The dielectric properties of different meteorite types can be discriminated, allowing radar to be used for interior compositional analysis. The primary trade is higher definition navigation for higher-resolution imaging, presuming that penetration requirements are met. It appears reliable that a SHARAD-type radar can image the global interior of a chondritic asteroid up to several km diameter. Radar imaging might leave a number of key questions unanswered, and to directly probe the mechanical behavior of an asteroid we conclude each rendezvous by observing one or more explosion cratering experiments. Cratering (CRT). Cratering is the primary mode of geologic evolution of asteroids, and meteoroid impacts can trigger outbursts on cometary nuclei. The process is important to study for its own sake, and a cratering experiment offers three additional science benefits: (1) final crater diameter and morphology indicates the mechanical behavior of regolith and other exterior materials; (2) cratering exposes the subsurface for analysis of interior materials; and (3) cratering might trigger global reverberations that can be detected using before-and-after image comparisons of toppled boulders and landslides. Small cratering events may be of global consequence on small asteroids (Asphaug, MAPS, in press) and thus a grenade of only a few kg is likely to send a detectable resurfacing reverberation spanning the asteroid. This experiment thus serves as a low cost proxy for primitive body seismology. Global seismic response is quantified using techniques that have been developed on Earth based on estimates for the dynamical acceleration of preciariously balanced rocks (Brune et al., JGR 2003). Ideally the mission would have two cratering charges per rendezvous target, differing by ˜2 orders of magnitude in yield, to bracket local to global response. Cratering and landslide physics will also be studied in this novel microgravity setting, for the purpose of establishing scaling rules and addressing fundamental problems of dense granular flow. Moreover, many cubic meters of ejected regolith are exposed for analysis of size distribution, clast shape, spectral heterogeneity, and dynamics. In the case that the asteroid is metastable (e.g. a rapid rotator), the small cratering event might trigger a global avalanche, in which case Deep Interior will observe the formation of transitory debris disks or small moons (e.g. Scheeres et al., Science 2007). Hazards to the spacecraft from these blast events have been computed from scaling laws for crater ejecta mass-velocity distributions, and are found to be minimal when the spacecraft is a few km away. This hazard drops to zero if the spacecraft is below the horizon of the blast, because dust is cleared out by the solar wind in about a day. Long term debris (moonlets and rings) are easily avoided since stable orbits are dynamically constrained (Scheeres et al., Icarus 1996). Unforeseen impacts with orbiting debris would occur at only a few cm/s.

Portable automated imaging in complex ceramics with a microwave interference scanning system

NASA Astrophysics Data System (ADS)

Goitia, Ryan M.; Schmidt, Karl F.; Little, Jack R.; Ellingson, William A.; Green, William; Franks, Lisa P.

2013-01-01

An improved portable microwave interferometry system has been automated to permit rapid examination of components with minimal operator attendance. Functionalities include stereo and multiplexed, frequency-modulated at multiple frequencies, producing layered volumetric images of complex ceramic structures. The technique has been used to image composite ceramic armor and ceramic matrix composite components, as well as other complex dielectric materials. The system utilizes Evisive Scan microwave interference scanning technique. Validation tests include artificial and in-service damage of ceramic armor, surrogates and ceramic matrix composite samples. Validation techniques include micro-focus x-ray and computed tomography imaging. The microwave interference scanning technique has demonstrated detection of cracks, interior laminar features and variations in material properties such as density. The image yields depth information through phase angle manipulation, and shows extent of feature and relative dielectric property information. It requires access to only one surface, and no coupling medium. Data are not affected by separation of layers of dielectric material, such as outer over-wrap. Test panels were provided by the US Army Research Laboratory, and the US Army Tank Automotive Research, Development and Engineering Center (TARDEC), who with the US Air Force Research Laboratory have supported this work.

Delivery of Cisplatin Anti-Cancer Drug from Carbon, Boron Nitride, and Silicon Carbide Nanotubes Forced by Ag-Nanowire: A Comprehensive Molecular Dynamics Study.

PubMed

Mehrjouei, Esmat; Akbarzadeh, Hamed; Shamkhali, Amir Nasser; Abbaspour, Mohsen; Salemi, Sirous; Abdi, Pooya

2017-07-03

In this work, liberation of cisplatin molecules from interior of a nanotube due to entrance of an Ag-nanowire inside it was simulated by classical molecular dynamics method. The aim of this simulation was investigation on the effects of diameter, chirality, and composition of the nanotube, as well as the influence of temperature on this process. For this purpose, single walled carbon, boron nitride, and silicon carbide nanotube were considered. In order for a more concise comparison of the results, a new parameter namely efficiency of drug release, was introduced. The results demonstrated that the efficiency of drug release is sensitive to its adsorption on outer surface of the nanotube. Moreover, this efficiency is also sensitive to the nanotube composition and its diameter. For the effect of nanotube composition, the results indicated that silicon carbide nanotube has the least efficiency for drug release, due to its strong drug-nanotube. Also, the most important acting forces on drug delivery are van der Waals interactions. Finally, the kinetic of drug release is fast and is not related to the structural parameters of the nanotube and temperature, significantly.

Design/Analysis of Metal/Composite Bonded Joints for Survivability at Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

Bartoszyk, Andrew E.

2004-01-01

A major design and analysis challenge for the JWST ISM structure is the metal/composite bonded joints that will be required to survive down to an operational ultra-low temperature of 30K (-405 F). The initial and current baseline design for the plug-type joint consists of a titanium thin walled fitting (1-3mm thick) bonded to the interior surface of an M555/954-6 composite truss square tube with an axially stiff biased lay-up. Metallic fittings are required at various nodes of the truss structure to accommodate instrument and lift-point bolted interfaces. Analytical experience and design work done on metal/composite bonded joints at temperatures below liquid nitrogen are limited and important analysis tools, material properties, and failure criteria for composites at cryogenic temperatures are virtually nonexistent. Increasing the challenge is the difficulty in testing for these required tools and parameters at 30K. A preliminary finite element analysis shows that failure due to CTE mismatch between the biased composite and titanium or aluminum is likely. Failure is less likely with Invar, however an initial mass estimate of Invar fittings demonstrates that Invar is not an automatic alternative. In order to gain confidence in analyzing and designing the ISM joints, a comprehensive joint development testing program has been planned and is currently running. The test program is designed for the correlation of the analysis methodology, including tuning finite element model parameters, and developing a composite failure criterion for the effect of multi-axial composite stresses on the strength of a bonded joint at 30K. The testing program will also consider stress mitigation using compliant composite layers and potential strength degradation due to multiple thermal cycles. Not only will the finite element analysis be correlated to the test data, but the FEA will be used to guide the design of the test. The first phase of the test program has been completed and the preliminary analysis has been revisited based on the test data In this work, we present an overview of the test plan, results today, and resulting design improvements.

Titan's interior from its rotation axis orientation and its Love number

NASA Astrophysics Data System (ADS)

Baland, Rose-Marie; Gabriel, Tobie; Axel, Lefèvre

2013-04-01

The tidal Love number k2 of Titan has been recently estimated from Cassini flybys radio-tracking and is consistent with the presence of a global ocean in Titan's interior, located between two ice layers (Iess et al. 2012), in accordance with prediction from interior and evolutionary models for Titan. Previously, the orientation of the rotation axis of Titan has been measured on the basis of radar images from Cassini (Stiles et al. 2008). Titan's obliquity, is about 0.3. The measured orientation is more consistent with the presence of a global internal liquid ocean than with an entirely solid Titan (Baland et al. 2011). The global topography data of Titan seem to indicate some departure from the hydrostatic shape expected for a synchronous satellite under the influence of its rotation and the static tides raised by the central planet (Zebker et al. 2009). This may be explained by a differential tidal heating in the ice shell which flattens the poles (Nimmo and Bills 2010). A surface more flattened than expected implies compensation in depth to explain the measured gravity coefficients C20 and C22 of Iess et al. (2012). Here, all layers are assumed to have a tri-axial ellipsoid shape, but with polar and equatorial flattenings that differ from the hydrostatic expected ones. We assess the influence of this non-hydrostatic shape on the conclusions of Baland et al. (2011), which developped a Cassini state model for the orientation of the rotation axis of a synchronous satellite having an internal liquid layer. We assess the possibility to constrain Titan's interior (and particularly the structure of the water/ice layer) from both the rotation axis orientation and the Love number. We consider a range of internal structure models consistent with the mean density and the mean radius of Titan, and made of a shell, an ocean, a mantle, and a core, from the surface to the center, with various possible compositions (e.g. ammonia mixed with water for the ocean). The internal structure models consistent with the measured orientation of the rotation axis and Love number still have to be examined with respect to other constrains, such as the shell thickness estimation derived from electric-field measurement of the Huyges probe (Béghin et al. 2012) and the expected temperature profile of the water/ice layer. For instance, a thin shell would imply a rather thick ocean, based on water (or water/ammonia) phase diagram.

Interior noise control ground test studies for advanced turboprop aircraft applications

NASA Technical Reports Server (NTRS)

Simpson, Myles A.; Cannon, Mark R.; Burge, Paul L.; Boyd, Robert P.

1989-01-01

The measurement and analysis procedures are documented, and the results of interior noise control ground tests conducted on a DC-9 aircraft test section are summarized. The objectives of these tests were to study the fuselage response characteristics of treated and untreated aircraft with aft-mount advanced turboprop engines and to analyze the effectiveness of selected noise control treatments in reducing passenger cabin noise on these aircraft. The results of fuselage structural mode surveys, cabin cavity surveys and sound intensity surveys are presented. The performance of various structural and cabin sidewall treatments is assessed, based on measurements of the resulting interior noise levels under simulated advanced turboprop excitation.

Advanced risk assessment of the effects of graphite fibers on electronic and electric equipment

NASA Technical Reports Server (NTRS)

Pocinki, L.; Cornell, M.; Kaplan, L.

1980-01-01

An assessment of the risk associated with accidents involving aircraft with carbon fiber composite structural components is examined. The individual fiber segments cause electrical and electronic equipment to fail under certain operating conditions. A Monte Carlo simulation model was used to computer the risk. Aircraft accidents with fire, release of carbon fiber material, entrainment of carbon fibers in a smoke plume transport of fibers downwind, transfer of some fibers/into the the interior of buildings, failures of electrical and electronic equipment, and economic impact of failures are discussed. Risk profiles were prepared for individual airports and the Nation. The vulnerability of electrical transmission equipment to carbon fiber incursion and aircraft accident total costs is investigated.

Efficient sulfur host based on NiCo2O4 hollow microtubes for advanced Li-S batteries

NASA Astrophysics Data System (ADS)

Iqbal, Azhar; Ali Ghazi, Zahid; Muqsit Khattak, Abdul; Ahmad, Aziz

2017-12-01

High energy density and cost effectiveness make lithium-sulfur battery a promising candidate for next-generation electrochemical energy storage technology. Here, we have synthesized a highly efficient sulfur host namely NiCo2O4 hollow microtubes/sulfur composite (NiCo2O4/S). The hollow interior cavity providing structural integrity while sufficient self-functionalized surfaces of NiCo2O4 chemically bind polysulfides to prevent their dissolution in the organic electrolyte. When used in lithium-sulfur batteries, the synthesized NiCo2O4/S cathode delivers high specific capacity (1274 mAh g-1 at 0.2 C), long cycling performance at 0.5 C, and good rate capability at high current rates.

Titan exploration with advanced systems. A study of future mission concepts

NASA Technical Reports Server (NTRS)

1983-01-01

The requirements, capabilities, and programmatic issues associated with science-intensive mission concepts for the advanced exploration of Saturn's largest satellite are assessed. The key questions to be answered by a Titan exploratory mission are: (1) the atmospheric composition; (2) the atmospheric structure; (3) the nature of the surface; and (4) the nature of the interior of Titan. Five selected mission concepts are described in terms of their design requirements. Mission hardware concepts include balloons and/or blimps which will allow both atmospheric and surface observations for a long period of time. Key aspects of performance analysis are presented. Mission profiles and cost summaries are given. Candidate payloads are identified for imaging and nonimaging orbiters, a buoyant station, a haze probe, and a penetrator.

Preparation of ZnS@In2S3 Core@shell Composite for Enhanced Photocatalytic Degradation of Gaseous o-Dichlorobenzene under Visible Light.

PubMed

Liu, Baojun; Hu, Xia; Li, Xinyong; Li, Ying; Chen, Chang; Lam, Kwok-Ho

2017-11-27

In this study, novel ZnS@In 2 S 3 core@shell hollow nanospheres were fabricated by a facile refluxing method for the first time, and the formation mechanism of hollow structure with interior architecture was discussed based on ion-exchange Ostwald ripening. As the photocatalytic material for degradation of gaseous o-Dichlorobenzene (o-DCB), the as-synthesized core@shell hollow nanospheres were found to show significantly enhanced catalytic performance for effective separation of photo-generated charges. Moreover, the mechanisms of enhanced activity were elucidated by band alignment and unique configuration. Such photocatalyst would meet the demands for the control of persistent organic pollutant (POPs) in the atmospheric environment.

Microbiology of Low Temperature Seafloor Deposits Along a Geochemical Gradient in Lau Basin

NASA Astrophysics Data System (ADS)

sylvan, J. B.; Sia, T. Y.; Haddad, A.; Briscoe, L. J.; Girguis, P. R.; Edwards, K. J.

2011-12-01

The East Lau Spreading Center (ELSC) and Valu Fa Ridge comprise a ridge segment in the southwest Pacific Ocean where rapid transitions in the underlying mantle lenses manifest themselves by gradients in seafloor rock geochemistry. At the spreading center in the north, basaltic host rock extrudes while the influence of subduction in the south creates mainly basaltic andesite host rock. A contuous gradient between these two end members exists along the spreading center. We studied the geology and microbial diversity of three silicate rock samples and three inactive sulfide chimney samples collected along the ELSC and Valu Fa Ridge by X-ray diffraction, elemental analysis, thin section analysis and construction of bacterial 16S rRNA clone libraries. Here, we discuss the geological and biological differences between the collected rocks. We found that the bacterial community composition changed as the host rock mineralogy and chemistry changed from north to south. Also, the bacterial community composition on the silicates is distinct from those on the inactive chimneys, and the interior conduit of an inactive chimney hosts a very different community from the exterior. Basalt from the northern end of the ELSC had high proportions of Alphaproteobacteria and Bacteroidetes. These proportions decreased on the silicates collected further south. Epsilonproteobacteria were also present on the basalt, decreased further south and were absent on the basaltic andesite. Conversely, basaltic andesite rocks from the southern end had high proportions of Chloroflexi, which decreased further north and were absent on basalt. The exterior of inactive sulfide structures were dominated by lineages of sulfur oxidizing Gammaproteobacteria and Epsilonproteobacteria and were less diverse than those on the silicates. The interior of one chimney was dominated by sulfate-reducing Deltaproteobacteria and was the least diverse of all samples. These results support the Mantle to Microbe hypothesis in that different types of Bacteria are selected by the composition of the host rock as determined by the melt lens underlying the hydrothermal vent field.

Interior Noise

NASA Technical Reports Server (NTRS)

Mixson, John S.; Wilby, John F.

1991-01-01

The generation and control of flight vehicle interior noise is discussed. Emphasis is placed on the mechanisms of transmission through airborne and structure-borne paths and the control of cabin noise by path modification. Techniques for identifying the relative contributions of the various source-path combinations are also discussed along with methods for the prediction of aircraft interior noise such as those based on the general modal theory and statistical energy analysis.

Martian impact craters - Correlations of ejecta and interior morphologies with diameter, latitude, and terrain

NASA Technical Reports Server (NTRS)

Barlow, Nadine G.; Bradley, Tracy L.

1990-01-01

An effort is made to establish the ability of a correlation between crater morphology and latitude, diameter, and terrain, to discriminate among the effects of impact energy, atmosphere, and subsurface volatiles in 3819 larger-than-8 km diameter craters distributed over the Martian surface. It is noted that changes in ejecta and interior morphology correlate with increases in crater diameter, and that while many of the interior structures exhibit distributions interpretable as terrain-dependent, central peak and peak ring interior morphologies exhibit minimal relationships with planetary properties.

A composite system approach to aircraft cabin fire safety

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.; Gilwee, W. J., Jr.; Lerner, N. R.; Hilado, C. J.; Labossiere, L. A.; Hsu, M.-T.

1976-01-01

The thermochemical and flammability characteristics of two polymeric composites currently in use and seven others being considered for use as aircraft interior panels are described. The properties studied included: (1) limiting oxygen index of the composite constituents; (2) fire containment capability of the composite; (3) smoke evolution from the composite; (4) thermogravimetric analysis; (5) composition of the volatile products of thermal degradation; and (6) relative toxicity of the volatile products of pyrolysis. The performance of high-temperature laminating resins such as bismaleimides is compared with the performance of phenolics and epoxies. The relationship of increased fire safety with the use of polymers with high anaerobic char yield is shown. Processing parameters of one of the bismaleimide composites is detailed.

A composite system approach to aircraft cabin fire safety

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.; Gilwee, W. J., Jr.; Lerner, N. R.; Hilado, C. J.; Labossiere, L. A.; Hsu, M. T. S.

1976-01-01

The thermochemical and flammability characteristics of two polymeric composites currently in use and seven others being considered for use as aircraft interior panels are described. The properties studied included: (1) limiting oxygen index of the composite constituents; (2) fire containment capability of the composite; (3) smoke evolution from the composite; (4) thermogravimetric analysis; (5) composition of the volatile products of thermal degradation; and (6) relative toxicity of the volatile products of pyrolysis. The performance of high temperature laminating resins such as bismaleimides is compared with the performance of phenolics and epoxies. The relationship of increased fire safety with the use of polymers with high anaerobic char yield is shown. Processing parameters of one of the baremaleimide composites are detailed.

Compound-specific isotopic analyses: a novel tool for reconstruction of ancient biogeochemical processes

NASA Technical Reports Server (NTRS)

Hayes, J. M.; Freeman, K. H.; Popp, B. N.; Hoham, C. H.

1990-01-01

Patterns of isotopic fractionation in biogeochemical processes are reviewed and it is suggested that isotopic fractionations will be small when substrates are large. If so, isotopic compositions of biomarkers will reflect those of their biosynthetic precursors. This prediction is tested by consideration of results of analyses of geoporphyrins and geolipids from the Greenhorn Formation (Cretaceous, Western Interior Seaway of North America) and the Messel Shale (Eocene, lacustrine, southern Germany). It is shown (i) that isotopic compositions of porphyrins that are related to a common source, but which have been altered structurally, cluster tightly and (ii) that isotopic differences between geolipids and porphyrins related to a common source are equal to those observed in modern biosynthetic products. Both of these observations are consistent with preservation of biologically controlled isotopic compositions during diagenesis. Isotopic compositions of individual compounds can thus be interpreted in terms of biogeochemical processes in ancient depositional environments. In the Cretaceous samples, isotopic compositions of n-alkanes are covariant with those of total organic carbon, while delta values for pristane and phytane are covariant with those of porphyrins. In this unit representing an open marine environment, the preserved acyclic polyisoprenoids apparently derive mainly from primary material, while the extractable, n-alkanes derive mainly from lower levels of the food chain. In the Messel Shale, isotopic compositions of individual biomarkers range from -20.9 to -73.4% vs PDB. Isotopic compositions of specific compounds can be interpreted in terms of origin from methylotrophic, chemautotrophic, and chemolithotrophic microorganisms as well as from primary producers that lived in the water column and sediments of this ancient lake.

Analytical model of the structureborne interior noise induced by a propeller wake

NASA Technical Reports Server (NTRS)

Junger, M. C.; Garrelick, J. M.; Martinez, R.; Cole, J. E., III

1984-01-01

The structure-borne contribution to the interior noise that is induced by the propeller wake acting on the wing was studied. Analytical models were developed to describe each aspect of this path including the excitation loads, the wing and fuselage structures, and the interior acoustic space. The emphasis is on examining a variety of parameters, and as a result different models were developed to examine specific parameters. The excitation loading on the wing by the propeller wake is modeled by a distribution of rotating potential vortices whose strength is related to the thrust per blade. The response of the wing to this loading is examined using beam models. A model of a beam structurally connected to a cylindrical shell with an internal acoustic fluid was developed to examine the coupling of energy from the wing to the interior space. The model of the acoustic space allows for arbitrary end conditions (e.g., rigid or vibrating end caps). Calculations are presented using these models to compare with a laboratory test configuration as well as for parameters of a prop-fan aircraft.

SiO{sub 2} nanospheres with tailorable interiors by directly controlling Zn{sup 2+} and NH{sub 3}.H{sub 2}O species in an emulsion process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liao Yuchao; Graduate University of Chinese Academy of Sciences, Beijing 100049; Wu Xiaofeng

2011-07-15

SiO{sub 2} nanospheres with tailorable interiors were synthesized by a facile one-spot microemulsion process using TEOS as silica source, wherein cyclohexane including triton X-100 and n-octanol as oil phase and Zn{sup 2+} or NH{sub 3}.H{sub 2}O aqueous solution as dispersive phase, respectively. The products were characterized by Scanning Electron Microscopy, Transmission Electron Microscopy and X-ray Powder Diffraction. It was suggested that the as-synthesized silica nanospheres possessed grape-stone-like porous or single hollow interior, and also found that the ammonia dosage and aging time played key roles in controlling the size and structure of silica nanospheres. Furthermore, the comparative results confirmed thatmore » in-situ zinc species [ZnO/Zn(OH){sub 2}] acted as the temporary templates to construct grape-stone-like interior, and a simultaneously competing etching process occurred owing to the soluble Zn(NH{sub 3}){sub 4}{sup 2+} complex formation while the additional excessive ammonia was introduced. With the aging time being extended, the in-situ nanocrystals tended to grow into bigger ones by Ostwald Ripening, producing single hollow interior. - Graphical Abstract: Formation process of SiO{sub 2} nanospheres with porous and single hollow interior. Highlights: > ZnO/Zn(OH){sub 2} nanocrystals as the temporary templates shape the interior structures of SiO{sub 2} nanospheres. > Fabrication of porous and single hollow interiors needs no additional processes such as roasting or dissolving. > Tailorable interiors can be easily obtained through adjusting the aging time of temporary templates.« less

Interior view of living and dining areas showing china dresser ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior view of living and dining areas showing china dresser and structural system, facing northeast. - Albrook Air Force Station, Field Officer's Quarters, West side of Dargue Avenue Circle, Balboa, Former Panama Canal Zone, CZ

INTERIOR; DETAIL OF ANTENNA TRUNK OPENING, LOOKING EAST. Naval ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR; DETAIL OF ANTENNA TRUNK OPENING, LOOKING EAST. - Naval Computer & Telecommunications Area Master Station, Eastern Pacific, Radio Transmitter Facility Lualualei, Helix House No. 2, Base of Radio Antenna Structure No. 427, Makaha, Honolulu County, HI

Structure and Evolution of Kuiper Belt Objects and Dwarf Planets

NASA Astrophysics Data System (ADS)

McKinnon, W. B.; Prialnik, D.; Stern, S. A.; Coradini, A.

Kuiper belt objects (KBOs) accreted from a mélange of volatile ices, carbonaceous matter, and rock of mixed interstellar and solar nebular provenance. The transneptunian region, where this accretion took place, was likely more radially compact than today. This and the influence of gas drag during the solar nebula epoch argue for more rapid KBO accretion than usually considered. Early evolution of KBOs was largely the result of heating due to radioactive decay, the most important potential source being 26Al, whereas long-term evolution of large bodies is controlled by the decay of U, Th, and 40K. Several studies are reviewed dealing with the evolution of KBO models, calculated by means of one-dimensional numerical codes that solve the heat and mass balance equations. It is shown that, depending on parameters (principally rock content and porous conductivity), KBO interiors may have reached relatively high temperatures. The models suggest that KBOs likely lost ices of very volatile species during early evolution, whereas ices of less-volatile species should be retained in cold, less-altered subsurface layers. Initially amorphous ice may have crystallized in KBO interiors, releasing volatiles trapped in the amorphous ice, and some objects may have lost part of these volatiles as well. Generally, the outer layers are far less affected by internal evolution than the inner part, which in the absence of other effects (such as collisions) predicts a stratified composition and altered porosity distribution. Kuiper belt objects are thus unlikely to be "the most pristine objects in the solar system," but they do contain key information as to how the early solar system accreted and dynamically evolved. For large (dwarf planet) KBOs, long-term radiogenic heating alone may lead to differentiated structures -- rock cores, ice mantles, volatile-ice-rich "crusts," and even oceans. Persistence of oceans and (potential) volcanism to the present day depends strongly on body size and the melting-point depression afforded by the presence of salts, ammonia, etc. (we review the case for Charon in particular). The surface color and compositional classes of KBOs are usually discussed in terms of "nature vs. nurture," i.e., a generic primordial composition vs. surface processing, but the true nature of KBOs also depends on how they have evolved. The broad range of albedos now found in the Kuiper belt, deep water-ice absorptions on some objects, evidence for differentiation of Pluto and 2003 EL61, and a range of densities incompatible with a single, primordial composition and variable porosity strongly imply significant, intrinsic compositional differences among KBOs. The interplay of formation zone (accretion rate), body size, and dynamical (collisional) history may yield KBO compositional classes (and their spectral correlates) that recall the different classes of asteroids in the inner solar system, but whose members are broadly distributed among the KBO dynamical subpopulations.

Feasibility of using piezoelectric actuators to control launch vehicle acoustics and structural vibrations

NASA Astrophysics Data System (ADS)

Niezrecki, Christopher; Cudney, Harley H.

2000-06-01

Future launch vehicle payload fairings will be manufactured form advanced lightweight composite materials. The loss of distributed mass causes a significant increase in the internal acoustic environment, causing a severe threat to the payload. Using piezoelectric actuators to control the fairing vibration and the internal acoustic environment has been proposed. To help determine the acoustic control authority of piezoelectric actuators mounted on a rocket fairing, the internal acoustic response created by the actuators needs to be determined. In this work, the internal acoustic response of a closed simply-supported (SS) cylinder actuated by piezoelectric (PZT) actuators is determined using a n impedance model for the actuator and boundary element analysis. The experimentally validated model is used to extrapolate results for a SS cylinder that emulates a Minotaur payload fairing. The internal cylinder acoustic levels are investigated for PZT actuation between 35 and 400 Hz. Significant reductions in the structural response due to increased damping do not equate to similar reductions in the acoustic SPLs for the cylinder. The sound levels at the acoustic resonant frequencies are essentially unaffected by the significant increase in structural damping while the acoustic level sat the structural resonant frequencies are mildly reduced. The interior acoustic response of the cylinder is dominated by the acoustic modes and therefore significant reductions in the overall interior acoustic levels will not be achieved if only the structural resonances are controlled. As the actuation frequency is reduced, the number of actuators required to generate acoustic levels commensurate to that found in the fairing increases to impractical values. Below approximately 100 Hz, the current demands reach levels that are extremely difficult to achieve with a practical system. The results of this work imply that PZT actuators do not have the authority to control the payload fairing internal acoustics below approximately 100 Hz.

Amino acids in the Yamato carbonaceous chrondrite from Antarctica

NASA Technical Reports Server (NTRS)

Shimoyama, A.; Ponnamperuma, C.; Yanai, K.

1979-01-01

Evidence for the presence of amino acids of extraterrestrial origin in the Antarctic Yamato carbonaceous chrondrite is presented. Hydrolyzed and nonhydrolyzed water-extracted amino acid samples from exterior, middle and interior portions of the meteorite were analyzed by an amino acid analyzer and by gas chromatography of N-TFA-isopropyl amino acid derivatives. Nine protein and six nonprotein amino acids were detected in the meteorite at abundances between 34 and less than one nmole/g, with equal amounts in interior and exterior portions. Nearly equal abundances of the D and L enantiomers of alanine, aspartic acid and glutamic acid were found, indicating the abiotic, therefore extraterrestrial, origin of the amino acids. The Antarctic environment and the uniformity of protein amino acid abundances are discussed as evidence against the racemization of terrestrially acquired amino acids, and similarities between Yamato amino acid compositions and the amino acid compositions of the Murchison and Murray type II carbonaceous chrondrites are indicated.

The Neutron Star Interior Composition Explorer (NICER)

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.; Gendreau, K.; Arzoumanian, Z.

2014-01-01

The Neutron Star Interior Composition Explorer (NICER) is an approved NASA Explorer Mission of Opportunity dedicated to the study of the extraordinary gravitational, electromagnetic, and nuclear-physics environments embodied by neutron stars. Scheduled to be launched in 2016 as an International Space Station payload, NICER will explore the exotic states of matter, using rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft (0.2-12 keV) X-ray band. Grazing-incidence "concentrator" optics coupled with silicon drift detectors, actively pointed for a full hemisphere of sky coverage, will provide photon-counting spectroscopy and timing registered to GPS time and position, with high throughput and relatively low background. The NICER project plans to implement a Guest Observer Program, which includes competitively selected user targets after the first year of flight operations. I will describe NICER and discuss ideas for potential Be/X-ray binary science.

High D/H ratios of water in magmatic amphiboles in Chassigny: Possible constraints on the isotopic composition of magmatic water on Mars

NASA Technical Reports Server (NTRS)

Watson, L. L.; Hutcheon, I. D.; Epstein, S.; Stolper, E. M.

1993-01-01

The D/H ratios of kaersutitic amphiboles contained in magmatic inclusions in the Shergottites Nakhlites Chassignites (SNC) meteorite Chassigny using the ion microprobe were measured. A lower limit on the delta(D(sub SMOW)) of the amphiboles is +1420 +/- 47 percent. Assuming Chassigny comes from Mars and the amphiboles have not been subject to alteration after their crystallization, this result implies either that recycling of D-enriched Martian atmosphere-derived waters into the planetary interior has taken place, or that the primordial hydrogen isotopic composition of the interior of Mars differs significantly from that of the Earth (delta(D(sub SMOW)) approximately 0 percent). In addition, the measurements indicate that the amphiboles contain less than 0.3 wt. percent water. This is much lower than published estimates, and indicates a less-hydrous Chassigny parent magma than previously suggested.

Special aspects for forming the interiors of thai shopping malls through the use of the biological approach

NASA Astrophysics Data System (ADS)

Kuznetsova, Iryna O.; Rosliakova, Ljubov V.; Zakharchuk, Viktorija L.; Samosudova, Natalia

2017-10-01

This study reviews the biological approach to Thai shopping mall’s interior design planning. The authors defined the principles of the mall’s design optimization in Thailand on the basis of the imitation of biological samples at constructive, art-compositional, organizational and ecological levels. The analysis of forming the shopping malls interiors and space-planning solutions is based on the imitation of eight basic levels of organization of living things: molecules, cells, tissues, organs, organisms, populations, ecosystem and biosphere. The examples of the direct and implicit application of biological analogues were demonstrated in the architecture and design of Thai shopping malls. In the study, the shopping mall is regarded as an open self-sufficient system with a high level of autonomy and a fortified structural organization that includes various functional components. On the basis of the analysis of existing Thai shopping malls, a list of the basic requirements for the design of the malls was compiled. This corresponds to the needs and desires of the modern customer and ensures the competitiveness of the establishment. The phenomenon of multisensory design approach that enhances the psychophysical comfort of the shopping mall visitors is described. Socio-cultural and geographical factors were identified which determine the development of biodesign in Thailand. The article reveals the potential for a combination of biology and design to enhance the aesthetics, ergonomics and efficiency of the shopping malls. The prospects within the development of this field and the possibility of applying the solutions in practice were explored.

The Architectural and Interior Design Planning Process.

ERIC Educational Resources Information Center

Cohen, Elaine

1994-01-01

Explains the planning process in designing effective library facilities and discusses library building requirements that result from electronic information technologies. Highlights include historical structures; Americans with Disabilities Act; resource allocation; electrical power; interior spaces; lighting; design development; the roles of…

26. INTERIOR VIEW SHOWING ROW OF TIMBER SUPPORT TOWERS BUILT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. INTERIOR VIEW SHOWING ROW OF TIMBER SUPPORT TOWERS BUILT AS TEMPORARY TRUSS REINFORCEMENT (NOTE STEEL STRUCTURES ATOP TIMBER BRACING) - Oakland Army Base, Transit Shed, East of Dunkirk Street & South of Burma Road, Oakland, Alameda County, CA

Methane related authigenic carbonates, chimneys and crusts from the Gulf of Cadiz

NASA Astrophysics Data System (ADS)

Magalhães, V.; Vasconcelos, C.; Gaspar, L.; Monteiro, H.; Pinheiro, L.; Ivanov, M.; Díaz-del-Río, V.; Somoza, L.

2003-04-01

During the TTR 11 and TTR 12 cruises (2001 and 2002), the area south and southwest of the Guadalquivir Diapiric Ridge was intensely surveyed with seismics, side scan sonar (MAK), underwater TV and sampling. This area is characterized by a very strong backscatter on the available side scan sonar images and a very irregular seafloor, with morphological and sedimentological features evidencing fluid escape structures (mud diapirs and mud volcanoes); and sedimentary structures associated with the outflow of the Mediterranean water (MOW). Based on the data and samples collected during the TTR11 and TTR12 cruises, complemented with data from the ANASTYA 2000 and 2001 cruises, it seems that this area corresponds to a large field of carbonate chimneys and crusts. Dredge profiles on the Iberico dome and west of this structure, on the main channel of the MOW, yielded a large amount of carbonate slabs and chimneys. These consist essentially of intrapelbiomicrite. Petrographic and XRD shows that their mineralogical composition consists mainly of dolomite, high magnesium calcite, quartz, feldspar and clays. Bioclasts of plantonic foraminifera (globigerinoids), ostracods and peletts are observed. Iron and manganese oxides are present and the cement is essentially biomicrite. In different samples from the same chimney a variation on the dolomite/calcite ratio is observed from the interior to the external part of the chimney. Values of dolomite show a variation from 47% in the interior to 17 % in the exterior. As regards Si02 (19-16%), Al2O3 (4-3%) and Fe2O3 (5-7%), the variations observed are not significant. Stable isotopic analysis of Carbon shown low d13C values (down to -46.88 per mil vs. PDB) and d18O up to + 4.90 per mil vs.

Olivine anisotropy suggests Gutenberg discontinuity is not the base of the lithosphere

PubMed Central

Qi, Chao; Warren, Jessica M.

2016-01-01

Tectonic plates are a key feature of Earth’s structure, and their behavior and dynamics are fundamental drivers in a wide range of large-scale processes. The operation of plate tectonics, in general, depends intimately on the manner in which lithospheric plates couple to the convecting interior. Current debate centers on whether the transition from rigid lithosphere to flowing asthenosphere relates to increases in temperature or to changes in composition such as the presence of a small amount of melt or an increase in water content below a specified depth. Thus, the manner in which the rigid lithosphere couples to the flowing asthenosphere is currently unclear. Here we present results from laboratory-based torsion experiments on olivine aggregates with and without melt, yielding an improved database describing the crystallographic alignment of olivine grains. We combine this database with a flow model for oceanic upper mantle to predict the structure of the seismic anisotropy beneath ocean basins. Agreement between our model and seismological observations supports the view that the base of the lithosphere is thermally controlled. This model additionally supports the idea that discontinuities in velocity and anisotropy, often assumed to be the base of the lithosphere, are, instead, intralithospheric features reflecting a compositional boundary established at midocean ridges, not a rheological boundary. PMID:27606485

Effect of boundary conditions on the numerical solutions of representative volume element problems for random heterogeneous composite microstructures

NASA Astrophysics Data System (ADS)

Cho, Yi Je; Lee, Wook Jin; Park, Yong Ho

2014-11-01

Aspects of numerical results from computational experiments on representative volume element (RVE) problems using finite element analyses are discussed. Two different boundary conditions (BCs) are examined and compared numerically for volume elements with different sizes, where tests have been performed on the uniaxial tensile deformation of random particle reinforced composites. Structural heterogeneities near model boundaries such as the free-edges of particle/matrix interfaces significantly influenced the overall numerical solutions, producing force and displacement fluctuations along the boundaries. Interestingly, this effect was shown to be limited to surface regions within a certain distance of the boundaries, while the interior of the model showed almost identical strain fields regardless of the applied BCs. Also, the thickness of the BC-affected regions remained constant with varying volume element sizes in the models. When the volume element size was large enough compared to the thickness of the BC-affected regions, the structural response of most of the model was found to be almost independent of the applied BC such that the apparent properties converged to the effective properties. Finally, the mechanism that leads a RVE model for random heterogeneous materials to be representative is discussed in terms of the size of the volume element and the thickness of the BC-affected region.

Olivine anisotropy suggests Gutenberg discontinuity is not the base of the lithosphere.

PubMed

Hansen, Lars N; Qi, Chao; Warren, Jessica M

2016-09-20

Tectonic plates are a key feature of Earth's structure, and their behavior and dynamics are fundamental drivers in a wide range of large-scale processes. The operation of plate tectonics, in general, depends intimately on the manner in which lithospheric plates couple to the convecting interior. Current debate centers on whether the transition from rigid lithosphere to flowing asthenosphere relates to increases in temperature or to changes in composition such as the presence of a small amount of melt or an increase in water content below a specified depth. Thus, the manner in which the rigid lithosphere couples to the flowing asthenosphere is currently unclear. Here we present results from laboratory-based torsion experiments on olivine aggregates with and without melt, yielding an improved database describing the crystallographic alignment of olivine grains. We combine this database with a flow model for oceanic upper mantle to predict the structure of the seismic anisotropy beneath ocean basins. Agreement between our model and seismological observations supports the view that the base of the lithosphere is thermally controlled. This model additionally supports the idea that discontinuities in velocity and anisotropy, often assumed to be the base of the lithosphere, are, instead, intralithospheric features reflecting a compositional boundary established at midocean ridges, not a rheological boundary.

Chamber-core structures for fairing acoustic mitigation

NASA Astrophysics Data System (ADS)

Ardelean, Emil; Williams, Andrew; Korshin, Nicholas; Henderson, Kyle; Lane, Steven; Richard, Robert

2005-05-01

Extreme noise and vibration levels at lift-off and during ascent can damage sensitive payload components. Recently, the Air Force Research Laboratory, Space Vehicles Directorate has investigated a composite structure fabrication approach, called chamber-core, for building payload fairings. Chamber-core offers a strong, lightweight structure with inherent noise attenuation characteristics. It uses one-inch square axial tubes that are sandwiched between inner and outer face-sheets to form a cylindrical fairing structure. These hollow tubes can be used as acoustic dampers to attenuate the amplitude response of low frequency acoustic resonances within the fairing"s volume. A cylindrical, graphite-epoxy chamber-core structure was built to study noise transmission characteristics and to quantify the achievable performance improvement. The cylinder was tested in a semi-reverberant acoustics laboratory using bandlimited random noise at sound pressure levels up to 110 dB. The performance was measured using external and internal microphones. The noise reduction was computed as the ratio of the spatially averaged external response to the spatially averaged interior response. The noise reduction provided by the chamber-core cylinder was measured over three bandwidths, 20 Hz to 500 Hz, 20 Hz to 2000 Hz, and 20 Hz to 5000 Hz. For the bare cylinder with no acoustic resonators, the structure provided approximately 13 dB of attenuation over the 20 Hz to 500 Hz bandwidth. With the axial tubes acting as acoustic resonators at various frequencies over the bandwidth, the noise reduction provided by the cylinder increased to 18.2 dB, an overall increase of 4.8 dB over the bandwidth. Narrow-band reductions greater than 10 dB were observed at specific low frequency acoustic resonances. This was accomplished with virtually no added mass to the composite cylinder.

Realization of FRC interior and exterior furniture

NASA Astrophysics Data System (ADS)

Šonka, Š.; Frantová, M.; Štemberk, P.; Havrda, J.; Janouch, P.

2017-09-01

This article deals with the implementation of fibre reinforced concrete for interior and exterior furniture. The use of fibre reinforced concrete for non-traditional and small structures brings some specifics in design and realization. These are, in particular, the design of a suitable mixture, the choice of the shape of the structure in relation to the technological possibilities of realization, the static effects and finally the actual production of the element.

4. Interior of second floor of Dixie Cotton Mill, view ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. Interior of second floor of Dixie Cotton Mill, view facing west. This area is now designated the upstairs yarn storage room. Note the change of column type and roof structure from the first to second column in foreground of photograph. The round columns were used in the 1913 addition to the original 1895 structure. - Dixie Cotton Mill, 710 Greenville Street, La Grange, Troup County, GA

Argon dye photocoagulator for microsurgery of the interior structure of the eye

NASA Astrophysics Data System (ADS)

Wolinski, Wieslaw L.; Kazmirowski, Antoni; Kesik, Jerzy; Korobowicz, Witold; Spytkowski, Wojciech

1991-08-01

Argon-dye laser photocoagulator for the microsurgery of the interior structure of the eye is described. Some technical specifications like power stability shape of the spots and the dependence of the power on the tissue vs. wavelenght for dye laser are given. Argon-dye photocoagulator was designed and constructed including argon laser tube and dye laser in Institute of Microelectronics and Optoelectronics Technical University of Warsaw.

Hemp as an Agricultural Commodity

DTIC Science & Technology

2014-02-14

yarns and raw or processed spun fibers, paper, carpeting, home furnishings, construction and insulation materials, auto parts, and composites. The...interior stalk (hurd) is used in various applications such as animal bedding, raw material inputs, low-quality papers, and composites. Hemp seed and...oilcake are used in a range of foods and beverages, and can be an alternative food protein source. Oil from the crushed hemp seed is an ingredient in a

Erosive Burning of Composite Solid Propellants: Experimental and Modeling Studies

DTIC Science & Technology

1978-08-01

of Crossflow on Solid Pro- appears that an additional mechanism(s) of erosive pallant Combustion: Interior Ballistic Design burning will have to be...Orlondo, Florida, July , 1977, AIAA Paper 77-930. 14. Lengelle,G., "Model Describing the Erosive Com- bustion and Velocity Response of Composite Pro...Propulsion Conference, Orlando, Florida, July , 1977. 17. Beddini, R.A., A Reacting Turbulent Boundary Layer Approach to Solid Propellant Erosive Burning, AFOSR

Insert Tidal Here: Finding Stability of Galilean Satellite Interiors

NASA Astrophysics Data System (ADS)

Walker, M.; Bills, B. G.; Mitchell, J.; Rhoden, A.

2017-12-01

The tidal environment is often hypothesized as a cause of surface expression in the satellites of the outer solar system. In two notable cases, Io's volcanism is thought to be driven by tidal heating of its mantle while the shattered surface of Europa's ice shell is said to be generated by tidal stresses in that ice. Being adjacent moons of Jupiter, these satellites give us a unique opportunity to apply a single set of general coupled models at each body to predict how one model can predict the heat generation and flow, strain and stress states, and structural parameters for each body. We include the effects of interior evolution into the tidal environment in addition to an evolving orbit. We find that the interiors of Io and Europa will evolve, as a consequence of the heat transfer from interior to surface, and stable structural and heat flow conditions are found. Then as their orbits evolve, perturbed by the mutual interactions of the Laplace mean motion resonance, those conditions of structural and heat stability also change. In particular, we find that at current orbital conditions there is sufficient heat to completely melt Io models for which a convecting interior is capped by a conducting lid. This argues for the presence of a non dissipating (or barely dissipating) core below the mantle, which future Io structure models should include. For the Europa model at current orbit, we use a silicate interior under an ocean capped by a two layer ice; convecting below with a conducting surface. We find stability in heat and structure occurs when the lower ice melts and recedes until the shell is roughly 50km thick. We present a variety of plausible structures for these bodies, and track how the stability of those structures trend as the orbit (in particular the orbital eccentricity, mean motion, and obliquity) change. We show how the Love numbers, layer thicknesses, surface heat flow, and orbital parameters are all linked. For Europa, upcoming measurements from Clipper should provide the necessary constraints to tune our model for the present day. This will also allow us to use today's initial conditions so that we can predict the history of the Galilean satellite's evolution as well as the changes we expect for their future.

Propeller aircraft interior noise model

NASA Technical Reports Server (NTRS)

Pope, L. D.; Wilby, E. G.; Wilby, J. F.

1984-01-01

An analytical model was developed to predict the interior noise of propeller-driven aircraft. The fuselage model is that of a cylinder with a structurally-integral floor. The cabin sidewall is stiffened by stringers and ring frames, and the floor by longitudinal beams. The cabin interior is covered with a sidewall treatments consisting of layers of porous material and an impervious trim septum. Representation of the propeller pressure field is utilized as input data in the form of the propeller noise signature at a series of locations on a grid over the fuselage structure. Results obtained from the analytical model are compared with test data measured by NASA in a scale model cylindrical fuselage excited by a model propeller.

Seismometers on Europa: Insights from Modeling and Antarctic Ice Shelf Analogs (Invited)

NASA Astrophysics Data System (ADS)

Schmerr, N. C.; Brunt, K. M.; Cammarano, F.; Hurford, T. A.; Lekic, V.; Panning, M. P.; Rhoden, A.; Sauber, J. M.

2013-12-01

The outer satellites of the Solar System are a diverse suite of objects that span a large spectrum of sizes, compositions, and evolutionary histories; constraining their internal structures is key for understanding their formation, evolution, and dynamics. In particular, Jupiter's icy satellite Europa has compelling evidence for the existence of a global subsurface ocean beneath a surface layer of water ice. This ocean decouples the ice shell from the solid silicate mantle, and amplifies tidally driven large-scale surface deformation. The complex fissures and cracks seen by orbital flybys suggest brittle failure is an ongoing and active process in the ice crust, therefore indicating a high level of associated seismic activity. Seismic probing of the ice, oceanic, and rocky layers would provide altogether new information on the structure, evolution, and even habitability of Europa. Any future missions (penetrators, landers, and rovers) planning to take advantage of seismometers to image the Europan interior would need to be built around predictions for the expected background noise levels, seismicity, wavefields, and elastic properties of the interior. A preliminary suite of seismic velocity profiles for Europa has been calculated using moment of inertia constraints, planetary mass and density, estimates of moon composition, thermal structure, and experimentally determined relationships of elastic properties for relevant materials at pressure, temperature and depth. While the uncertainties in these models are high, they allow us to calculate a first-order seismic response using 1-D and 3-D high frequency wave propagation codes for global and regional scale structures. Here, we show how future seismic instruments could provide detailed elastic information and reduced uncertainties on the internal structure of Europa. For example, receiver functions and surface wave orbits calculated for a single seismic instrument would provide information on crustal thickness and the depth of an ocean layer. Likewise, evaluation of arrival times of reflected wave multiples observed at a single seismic station would record properties of the mantle and core of Europa. Cluster analysis of waveforms from various seismic source mechanisms could be used to classify different types of seismicity originating from the ice and rocky parts of the moon. We examine examples of single station results for analogous seismic experiments on Earth, e.g., where broadband, 3-component seismometers have been placed upon the Ross Ice Shelf of Antarctica. Ultimately this work reveals that seismometer deployments will be essential for understanding the internal dynamics, habitability, and surface evolution of Europa, and that seismic instruments need to be a key component of future missions to surface of Europa and outer satellites.

Biomimetic composite coating on rapid prototyped scaffolds for bone tissue engineering.

PubMed

Arafat, M Tarik; Lam, Christopher X F; Ekaputra, Andrew K; Wong, Siew Yee; Li, Xu; Gibson, Ian

2011-02-01

The objective of this present study was to improve the functional performance of rapid prototyped scaffolds for bone tissue engineering through biomimetic composite coating. Rapid prototyped poly(ε-caprolactone)/tri-calcium phosphate (PCL/TCP) scaffolds were fabricated using the screw extrusion system (SES). The fabricated PCL/TCP scaffolds were coated with a carbonated hydroxyapatite (CHA)-gelatin composite via biomimetic co-precipitation. The structure of the prepared CHA-gelatin composite coating was studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Compressive mechanical testing revealed that the coating process did not have any detrimental effect on the mechanical properties of the scaffolds. The cell-scaffold interaction was studied by culturing porcine bone marrow stromal cells (BMSCs) on the scaffolds and assessing the proliferation and bone-related gene and protein expression capabilities of the cells. Confocal laser microscopy and SEM images of the cell-scaffold constructs showed a uniformly distributed cell sheet and accumulation of extracellular matrix in the interior of CHA-gelatin composite-coated PCL/TCP scaffolds. The proliferation rate of BMSCs on CHA-gelatin composite-coated PCL/TCP scaffolds was about 2.3 and 1.7 times higher than that on PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds, respectively, by day 10. Furthermore, reverse transcription polymerase chain reaction and Western blot analysis revealed that CHA-gelatin composite-coated PCL/TCP scaffolds stimulate osteogenic differentiation of BMSCs the most, compared with PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds. These results demonstrate that CHA-gelatin composite-coated rapid prototyped PCL/TCP scaffolds are promising for bone tissue engineering. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Thermal Profile of the Lunar Interior Constrained by Revised Estimates of Concentrations of Heat Producing Elements

NASA Astrophysics Data System (ADS)

Fuqua-Haviland, H.; Panovska, S.; Mallik, A.; Bremner, P. M.; McDonough, W. F.

2017-12-01

Constraining the heat producing element (HPE) concentrations of the Moon is important for understanding the thermal state of the interior. The lunar HPE budget is debated to be suprachondritic [1] to chondritic [2]. The Moon is differentiated, thus, each reservoir has a distinct HPE signature complicating this effort. The thermal profile of the lunar interior has been constructed using HPE concentrations of an ordinary chondrite (U = 0.0068 ppm; Th = 0.025 ppm; K = 17 ppm) which yields a conservative low estimate [2, 3, 4]. A later study estimated the bulk lunar mantle HPE concentrations (U = 0.039 ppm; Th = 0.15 ppm; K = 212 ppm) based on measurements of Apollo pyroclastic glasses [5] assuming that these glasses represent the least fractionated, near-primary lunar mantle melts, hence, are the best proxies for capturing mantle composition. In this study, we independently validate the revised estimate by using HPE concentrations [5] to construct a conductive lunar thermal profile, or selenotherm. We compare our conductive profile to the range of valid temperatures. We demonstrate the HPE concentrations reported by [5], when used in a simple 1D spherical thermal conduction equation, yield an impossibly hot mantle with temperatures in excess of 4,000 K (Fig 1). This confirms their revised estimate is not representative of the bulk lunar mantle, and perhaps only representative of a locally enriched mantle domain. We believe that their Low-Ti avg. source estimate (Th = 0.055 ppm, Th/U=4; K/U=1700), with the least KREEP assimilation is the closest representation of the bulk lunar mantle, producing 3E-12 W/kg of heat. This estimate is close to that of the Earth (5E-12 W/kg), indicating that the bulk Earth and lunar mantles are similar in their HPE constituents. We have used the lunar mantle heat production, in conjunction with HPE estimates of the Fe-Ti-rich cumulates (high Ti-source estimate from [5]) and measurements of crustal ferroan anorthite [6], to capture the present-day lunar interior thermal state. We also present plausible internal structures that best match the mass, moment of inertia and bulk silicate Moon composition along this conductive selenotherm. [1] Wanke et al (1973) LPSC; [2] Warren et al (1979) Rev Geophy; [3] Wieczorek et al (2000) JGR; [4] Grimm (2013) JGRP; [5] Hagerty et al (2006) GCA; [6] Peplowski et al (2016) JGR.

Planetary Magnetic Fields: Planetary Interiors and Habitability W. M. Keck Institute for Space Studies Report

NASA Astrophysics Data System (ADS)

Lazio, T. Joseph; Shkolnik, Evgenya; Hallinan, Gregg

2017-05-01

The W. M. Keck Institute for Space Studies (KISS) sponsored the "Planetary Magnetic Fields: Planetary Interiors and Habitability" study to review the state of knowledge of extrasolar planetary magnetic fields and the prospects for their detection.There were multiple motivations for this Study. Planetary-scale magnetic fields are a window to a planet's interior and provide shielding of the planet's atmosphere. The Earth, Mercury, Ganymede, and the giant planets of the solar system all contain internal dynamo currents that generate planetary-scale magnetic fields. In turn, these internal dynamo currents arise from differential rotation, convection, compositional dynamics, or a combination of these in objects' interiors. If coupled to an energy source, such as the incident kinetic or magnetic energy from the solar wind or an orbiting satellite, a planet's magnetic field can produce intense electron cyclotron masers in its magnetic polar regions. The most well known example of this process in the solar system is the Jovian decametric emission, but all of the giant planets and the Earth contain similar electron cyclotron masers within their magnetospheres. Extrapolated to extrasolar planets, the remote detection of the magnetic field of an extrasolar planet would provide a means of obtaining constraints on the thermal state, composition, and dynamics of its interior--all of which will be difficult to determine by other means--as well as improved understanding of the basic planetary dynamo process.We review the findings from the Study, including potential mission concepts that emerged and recent developments toward one of the mission concepts, a space-based radio wavelength array. There was an identification of that radio wavelength observations would likely be key to making significant progress in this field.We acknowledge ideas and advice from the participants in the "Planetary Magnetic Fields: Planetary Interiors and Habitability" study organized by the W. M. Keck Institute for Space Studies. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Morphology and deformational history of Tellus Regio, Venus: Evidence for assembly and collision

NASA Astrophysics Data System (ADS)

Gilmore, M. S.; Head, J. W.

2018-05-01

Tessera terrain is the oldest stratigraphic unit on Venus, but its origin and evolution are inadequately understood. Here we have performed detailed mapping of Tellus Regio, the third largest tessera plateau on Venus. Tellus Regio is shown to have distinct marginal and interior facies. The east and west margins of Tellus rise up to 2 km above the interior and include ridges and troughs ∼5-20 km across, oriented parallel to the present plains-tessera boundary. Structures characteristic of the interior of Tellus are found within the eastern and western margins and are deformed by the margin-parallel ridges indicating their presence during the time of the formation of the current margins. These relationships suggest that the margins formed by the application of external horizontal compressional stresses at the edges of an already-existing tessera interior. Structural and stratigraphic relationships in southwest Tellus show the assembly of three structurally distinct tessera regions and intervening plains that are consistent with the collision of the southwest margin into the plateau interior. This requires that tessera terrain was formed regionally and collected into the present day Tellus plateau. The latest stages of activity in Tellus include volcanism and pervasive, distributed, 1-2 km wide graben, which may have been formed due to large-scale gravitational relaxation of the plateau topography. A large intratessera plains unit may have formed via crustal delamination. The collisional oroclinal deformation of the margins are most consistent with models that invoke mantle downwelling for the origin of Tellus Regio and other tessera plateaus with similar structural relationships.

A wet, heterogeneous lunar interior: Lower mantle and core dynamo evolution

NASA Astrophysics Data System (ADS)

Evans, A. J.; Zuber, M. T.; Weiss, B. P.; Tikoo, S. M.

2014-05-01

While recent analyses of lunar samples indicate the Moon had a core dynamo from at least 4.2-3.56 Ga, mantle convection models of the Moon yield inadequate heat flux at the core-mantle boundary to sustain thermal core convection for such a long time. Past investigations of lunar dynamos have focused on a generally homogeneous, relatively dry Moon, while an initial compositionally stratified mantle is the expected consequence of a postaccretionary lunar magma ocean. Furthermore, recent re-examination of Apollo samples and geophysical data suggests that the Moon contains at least some regions with high water content. Using a finite element model, we investigate the possible consequences of a heterogeneously wet, compositionally stratified interior for the evolution of the Moon. We find that a postoverturn model of mantle cumulates could result in a core heat flux sufficiently high to sustain a dynamo through 2.5 Ga and a maximum surface, dipolar magnetic field strength of less than 1 μT for a 350-km core and near ˜2 μT for a 450-km core. We find that if water was transported or retained preferentially in the deep interior, it would have played a significant role in transporting heat out of the deep interior and reducing the lower mantle temperature. Thus, water, if enriched in the lower mantle, could have influenced core dynamo timing by over 1.0 Gyr and enhanced the vigor of a lunar core dynamo. Our results demonstrate the plausibility of a convective lunar core dynamo even beyond the period currently indicated by the Apollo samples.

Numerical modeling of the exterior-to-interior transmission of impulsive sound through three-dimensional, thin-walled elastic structures

NASA Astrophysics Data System (ADS)

Remillieux, Marcel C.; Pasareanu, Stephanie M.; Svensson, U. Peter

2013-12-01

Exterior propagation of impulsive sound and its transmission through three-dimensional, thin-walled elastic structures, into enclosed cavities, are investigated numerically in the framework of linear dynamics. A model was developed in the time domain by combining two numerical tools: (i) exterior sound propagation and induced structural loading are computed using the image-source method for the reflected field (specular reflections) combined with an extension of the Biot-Tolstoy-Medwin method for the diffracted field, (ii) the fully coupled vibro-acoustic response of the interior fluid-structure system is computed using a truncated modal-decomposition approach. In the model for exterior sound propagation, it is assumed that all surfaces are acoustically rigid. Since coupling between the structure and the exterior fluid is not enforced, the model is applicable to the case of a light exterior fluid and arbitrary interior fluid(s). The structural modes are computed with the finite-element method using shell elements. Acoustic modes are computed analytically assuming acoustically rigid boundaries and rectangular geometries of the enclosed cavities. This model is verified against finite-element solutions for the cases of rectangular structures containing one and two cavities, respectively.

Materials research for aircraft fire safety

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.; Bricker, R. W.

1976-01-01

The thermochemical and flammability characteristics of two polymeric composites currently in use and seven others being considered for use as aircraft interior panels are described. The properties studied included: (1) limiting oxygen index of the composite constituents; (2) fire containment capability of the composite; (3) smoke evolution from the composite; (4) thermogravimetric analysis; (5) composition of the volatile products of thermal degradation; and (6) relative toxicity of the volatile products of pyrolysis. The performance of high-temperature laminating resins such as bismaleimides is compared with the performance of phenolics and epoxies. The relationship of increased fire safety with the use of polymers with high anaerobic char yield is shown. Processing parameters of the state-of-the-art and the advanced bismaleimide composites are detailed.

INTERIOR; VIEW OF ANTENNA TRUNK OPENING AND ENTRY DOOR, LOOKING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR; VIEW OF ANTENNA TRUNK OPENING AND ENTRY DOOR, LOOKING EAST SOUTHEAST. - Naval Computer & Telecommunications Area Master Station, Eastern Pacific, Radio Transmitter Facility Lualualei, Helix House No. 2, Base of Radio Antenna Structure No. 427, Makaha, Honolulu County, HI

Looking west, this interior photograph, taken in the second floor ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Looking west, this interior photograph, taken in the second floor of E Building, demonstrates one of the typical corridors of the structure - Department of Energy, Mound Facility, Electronics Laboratory Building (E Building), One Mound Road, Miamisburg, Montgomery County, OH

Interior detail of south wall with shed roofs showing steel ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior detail of south wall with shed roofs showing steel structure, paint room on lower right, view facing west-southwest - U.S. Naval Base, Pearl Harbor, Boat Shop, Seventh Street near Avenue E, Pearl City, Honolulu County, HI

Neutron star Interior Composition Explorer (NICER)

NASA Image and Video Library

2017-12-08

NICER’s X-ray concentrator optics are inspected under a black light for dust and foreign object debris that could impair functionality once in space. The payload’s 56 mirror assemblies concentrate X-rays onto silicon detectors to gather data that will probe the interior makeup of neutron stars, including those that appear to flash regularly, called pulsars. The Neutron star Interior Composition Explorer (NICER) is a NASA Explorer Mission of Opportunity dedicated to studying the extraordinary environments — strong gravity, ultra-dense matter, and the most powerful magnetic fields in the universe — embodied by neutron stars. An attached payload aboard the International Space Station, NICER will deploy an instrument with unique capabilities for timing and spectroscopy of fast X-ray brightness fluctuations. The embedded Station Explorer for X-ray Timing and Navigation Technology demonstration (SEXTANT) will use NICER data to validate, for the first time in space, technology that exploits pulsars as natural navigation beacons. Credit: NASA/Goddard/ Keith Gendreau NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Neutron star Interior Composition Explorer (NICER)

NASA Image and Video Library

2017-12-08

NICER engineer Steven Kenyon prepares seven of the 56 X-ray concentrators for installation in the NICER instrument. The payload’s 56 mirror assemblies concentrate X-rays onto silicon detectors to gather data that will probe the interior makeup of neutron stars, including those that appear to flash regularly, called pulsars. The Neutron star Interior Composition Explorer (NICER) is a NASA Explorer Mission of Opportunity dedicated to studying the extraordinary environments — strong gravity, ultra-dense matter, and the most powerful magnetic fields in the universe — embodied by neutron stars. An attached payload aboard the International Space Station, NICER will deploy an instrument with unique capabilities for timing and spectroscopy of fast X-ray brightness fluctuations. The embedded Station Explorer for X-ray Timing and Navigation Technology demonstration (SEXTANT) will use NICER data to validate, for the first time in space, technology that exploits pulsars as natural navigation beacons. Credit: NASA/Goddard/ Keith Gendreau NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Hematite Spherules of Meridiani Planum: Implications for Aqueous History at the Site

NASA Astrophysics Data System (ADS)

Calvin, W. M.

2004-12-01

The thermal infrared spectral signature of bulk, grey hematite was the chemical "beacon" that focused the selection of Meridiani Planum as the landing site for the Mars Exploration Rover Opportunity, and aqueous processes were favored for its formation. Orbital data suggesting more bound water in accessory minerals at this location also supported this interpretation. After landing January 24, 2004, the Mini-TES instrument rapidly confirmed the thermal spectral signature of bulk hematite in soils on the plains surrounding Eagle crater and unevenly distributed within the crater. Observations within Eagle crater soon uncovered unusual spherical grains in abundance surrounding the outcrop and Microscopic Imager (MI) showed these grains eroding from within these rocks. They were dubbed "blueberries" by the team due to their spherical nature and their grey or blue appearance compared to their surroundings in various color composites of Pancam images. Extensive observations with the Mössbauer, Alpha-Particle X-ray Spectrometer (APXS) and Mini-TES instruments, especially of the "Berry Bowl" (i.e. with berries and adjacent berry-free rock), confirmed that these spherules are dominantly composed of hematite. Pancam spectra of individual spheres also match laboratory spectra of hematite. These spheres are found within and around outcrop rocks, across the plains of Meridiani, and rolling into the interior of Endurance crater. They are ubiquitous and remarkably even in size and tone. Grains are spherical to subspherical typically 2 to 6 mm in diameter. Opportunity has performed numerous operations with the Rock Abrasion Tool (RAT), and has sliced through individual spherules. The appearance after ratting shows limited or no interior structure and they remain uniformly grey in color. They can preserve scratches from the grinding wheel or become dislodged by ratting, indicating they are harder than the host rock. Several lines of evidence suggest the spheres are post-depositional diagenetic products. On Earth, oolitic iron occurs as concretions in Utah and in the Clinton Formation outcropping from New York into Alabama. Ferromanganese nodules occur in abundance on the modern sea floor and are found in the Great Lakes. Although diagenetic in origin, these terrestrial analogs have strong contrasts with what is observed on Mars, including diverse size, shape and composition of terrestrial samples, significant interior lamination and presence of nucleation centers that are lacking in the Martian spheres. The uniformity of composition and size of the Martian examples provide clues to the redox state of fluids at the time of formation and by analogy with seafloor nodules a rough estimate of the time required for growth.

Structured copolymers and their use as absorbents, gels and carriers of metal ions

DOEpatents

Hedstrand, David M.; Helmer, Bradley J.; Tomalia, Donald A.

1996-01-01

Dense star polymers or dendrimers having a highly branched interior structure capable of associating or chelating with metal ions are modified by capping with a hydrophobic group capable of providing a hydrophobic outer shell. The modified dendrimers are useful for dispersing metal ions in a non-aqueous polymer matrix. Also dense star polymers or dendrimers having a highly branched hydrophilic interior structure are modified by capping with a hydrophobic group capable of providing a hydrophobic outer shell, which modified polymers are useful as gels and surfactants.

Structured copolymers and their use as absorbents, gels and carriers of metal ions

DOEpatents

Hedstrand, D.M.; Helmer, B.J.; Tomalia, D.A.

1996-10-01

Dense star polymers or dendrimers having a highly branched interior structure capable of associating or chelating with metal ions are modified by capping with a hydrophobic group capable of providing a hydrophobic outer shell. The modified dendrimers are useful for dispersing metal ions in a non-aqueous polymer matrix. Also dense star polymers or dendrimers having a highly branched hydrophilic interior structure are modified by capping with a hydrophobic group capable of providing a hydrophobic outer shell, which modified polymers are useful as gels and surfactants.

Characterization of Thermal Behavior of Epoxy Composites Reinforced with Curaua Fibers by Differential Scanning Calorimetry

NASA Astrophysics Data System (ADS)

Barcelos, Mariana A.; Ribeiro, Carolina Gomes D.; Ferreira, Jordana; Vieira, Janaina da S.; Margem, Frederico M.; Monteiro, Sergio N.

Epoxy composites reinforced with natural lignocellulosic fibers have, in recent times, been gaining attention in engineering areas as lighter and cheaper alternatives for traditional composites such as the "fiberglass". The curaua fiber is the one strongest today being considered as reinforcement of composites for automobile interior parts. In fact, several studies are currently being dedicated to curaua fiber composites since physical and mechanical properties are required for practical uses. In this work, the thermal behavior of epoxy composites reinforced with up to 30 % in volume of curaua fibers was investigated by differential scanning calorimetry, DSC. The results showed endothermic and exothermic events associated with water release and possible molecular chain amorphous transformation. Comparison with similar composites permitted to propose mechanism that explains this DSC thermal behavior.

Formation and composition of the moon

NASA Technical Reports Server (NTRS)

Anderson, D. L.

1977-01-01

Many of the properties of the Moon, including the enrichment in Ca, Al, Ti, U, Th, Ba, Sr, and the REE and the depletion in Fe, Rb, K, Na, and other volatiles can be understood if the Moon represents a high-temperature condensate from the solar nebula. Thermodynamic calculations show that Ca-, Al-, and Ti-rich compounds condense first in a cooling nebula. The initial high temperature mineralogy is gehlenite, spinel, perovskite, Ca-Al-rich pyroxenes, and anorthite. Inclusions in carbonaceous chondrites such as the Allende meteorite are composed primarily of these minerals and, in addition, are highly enriched in refractories such as REE relative to carbonaceous chondrites. These inclusions can yield basalt and anorthosite in the proportions required to eliminate the europium anomaly, leaving a residual spinel-melilite interior. A deep interior high in Ca-Al does not imply an unacceptable mean density or moment of inertia for the Moon. The inferred high-U content of the lunar interior, both from the Allende analog and the high heat flow, indicates a high-temperature interior. The model is consistent with extensive early melting, with shallow melting at 3 AE, and with presently high deep internal temperatures. It is predicted that the outer 250 km is rich in plagioclase and FeO. The low iron content of the interior in this model raises the interior temperatures estimated from electrical conductivity by some 800 C.

Metal-silicate Partitioning and Its Role in Core Formation and Composition on Super-Earths

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schaefer, Laura; Petaev, M. I.; Sasselov, Dimitar D.

We use a thermodynamic framework for silicate-metal partitioning to determine the possible compositions of metallic cores on super-Earths. We compare results using literature values of the partition coefficients of Si and Ni, as well as new partition coefficients calculated using results from laser shock-induced melting of powdered metal-dunite targets at pressures up to 276 GPa, which approaches those found within the deep mantles of super-Earths. We find that larger planets may have little to no light elements in their cores because the Si partition coefficient decreases at high pressures. The planet mass at which this occurs will depend on themore » metal-silicate equilibration depth. We also extrapolate the equations of state (EOS) of FeO and FeSi alloys to high pressures, and present mass–radius diagrams using self-consistent planet compositions assuming equilibrated mantles and cores. We confirm the results of previous studies that the distribution of elements between mantle and core will not be detectable from mass and radius measurements alone. While observations may be insensitive to interior structure, further modeling is sensitive to compositionally dependent properties, such as mantle viscosity and core freeze-out properties. We therefore emphasize the need for additional high pressure measurements of partitioning as well as EOSs, and highlight the utility of the Sandia Z-facilities for this type of work.« less

3D high-resolution radar imaging of small body interiors

NASA Astrophysics Data System (ADS)

Sava, Paul; Asphaug, Erik

2017-10-01

Answering fundamental questions about the origin and evolution of small planetary bodies hinges on our ability to image their interior structure in detail and at high resolution (Asphaug, 2009). We often infer internal structure from surface observations, e.g. that comet 67P/Churyumov-Gerasimenko is a primordial agglomeration of cometesimals (Massironi et al., 2015). However, the interior structure is not easily accessible without systematic imaging using, e.g., radar transmission and reflection data, as suggested by the CONSERT experiment on Rosetta. Interior imaging depends on observations from multiple viewpoints, as in medical tomography.We discuss radar imaging using methodology adapted from terrestrial exploration seismology (Sava et al., 2015). We primarily focus on full wavefield methods that facilitate high quality imaging of small body interiors characterized by complex structure and large contrasts of physical properties. We consider the case of a monostatic system (co-located transmitters and receivers) operated at two frequency bands, centered around 5 and 15 MHz, from a spacecraft in slow polar orbit around a spinning comet nucleus. Assuming that the spin period is significantly (e.g. 5x) faster than the orbital period, this configuration allows repeated views from multiple directions (Safaeinili et al., 2002)Using realistic numerical experiments, we argue that (1) the comet/asteroid imaging problem is intrinsically 3D and conventional SAR methodology does not satisfy imaging, sampling and resolution requirements; (2) imaging at different frequency bands can provide information about internal surfaces (through migration) and internal volumes (through tomography); (3) interior imaging can be accomplished progressively as data are being acquired through successive orbits around the studied object; (4) imaging resolution can go beyond the apparent radar frequency band by deconvolution of the point-spread-function characterizing the imaging system; and (5) exploiting the known (and complex) exterior shape of the studied body facilitates high-resolution imaging and tomography comparable with what could be accomplished by bi/multi-static systems.

Molluscan extinction patterns across the Cenomanian-Turonian stage boundary in the western interior of the United States

USGS Publications Warehouse

Elder, W.P.

1989-01-01

High-resolution stratigraphic analysis of 18 sections spanning the Cenomanian-Turonian Stage boundary in the western interior of the United States has allowed determination of the magnitude and pattern of molluscan extinction and disruption. Composite range data from all sections show that the faunal turnover across the stage boundary occurs in a series of narrow stratigraphic zones, defined by multiple first and last occurrences, separated by intervals displaying little or no taxonomic turnover. Two of the apparent extinction steps (bottom and top of the Neocardioceras juddii Zone) may be intercontinentally developed. The additional steps apparently reflect cyclic changes in water mass and substrate characteristics in the western interior basin produced in response to orbital forcing of climate. The most affected mollusks were those having intercontinental distributions. -Author

Aircraft Interior Noise Control Using Distributed Piezoelectric Actuators

NASA Technical Reports Server (NTRS)

Sun, Jian Q.

1996-01-01

Developing a control system that can reduce the noise and structural vibration at the same time is an important task. This talk presents one possible technical approach for accomplishing this task. The target application of the research is for aircraft interior noise control. The emphasis of the present approach is not on control strategies, but rather on the design of actuators for the control system. In the talk, a theory of distributed piezoelectric actuators is introduced. A uniform cylindrical shell is taken as a simplified model of fuselage structures to illustrate the effectiveness of the design theory. The actuators developed are such that they can reduce the tonal structural vibration and interior noise in a wide range of frequencies. Extensive computer simulations have been done to study various aspects of the design theory. Experiments have also been conducted and the test results strongly support the theoretical development.

Genetic structure of tree and shrubby species among anthropogenic edges, natural edges, and interior of an atlantic forest fragment.

PubMed

Ramos, Flavio Nunes; de Lima, Paula Feliciano; Zucchi, Maria Imaculada; Colombo, Carlos Augusto; Solferini, Vera Nisaka

2010-04-01

Two species, Psychotria tenuinervis (shrub, Rubiaceae) and Guarea guidonia (tree, Meliaceae), were used as models to compare the genetic structure of tree and shrubby species among natural edges, anthropogenic edges, and a fragment interior. There were significant differences between two genetic markers. For isozymes, P. tenuinervis presented greater heterozygosity (expected and observed) and a higher percentage of polymorphic loci and median number of alleles than G. guidonia. For microsatellites, there was no difference in genetic variability between the species. Only P. tenuinervis, for isozymes, showed differences in genetic variability among the three habitats. There was no genetic structure (F (ST) < 0.05) among habitats in both plant species for both genetic markers. Isozymes showed great endogamy for both plant species, but not microsatellites. The forest fragmentation may have negative effects on both spatial (among edges and interior) and temporal genetic variability.

Design of PdAg Hollow Nanoflowers through Galvanic Replacement and Their Application for Ethanol Electrooxidation.

PubMed

Bin, Duan; Yang, Beibei; Zhang, Ke; Wang, Caiqin; Wang, Jin; Zhong, Jiatai; Feng, Yue; Guo, Jun; Du, Yukou

2016-11-07

In this study, galvanic replacement provides a simple route for the synthesis of PdAg hollow nanoflower structures by using the Ag-seeds as sacrificial templates in the presence of l-ascorbic acid (reductant) and CTAC (capping agent). Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and EDS mapping were used to characterize the as-prepared PdAg hollow nanoflower catalysts, where they were alloyed nanoflower structures with hollow interiors. By maneuvering the Pd/Ag ratio, we found that the as-prepared Pd 1 Ag 3 hollow nanoflower catalysts had the optimized performance for catalytic activity toward ethanol oxidation reaction. Moreover, these as-prepared PdAg hollow nanoflower catalysts exhibited noticeably higher electrocatalytic activity as compared to pure Pd and commercial Pd/C catalysts due to the alloyed Ag-Pd composition as well as the hollow nanoflower structures. It is anticipated that this work provides a rational design of other architecturally controlled bimetallic nanocrystals for application in fuel cells. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Iraqi Army: A Year of Progress - U.S. Department of Defense Official

Science.gov Websites

Ministry of Defense and Iraqi Ministry of the Interior intelligence structure must support the Iraqi Police activities in conjunction with the policies of the Iraqi Ministry of Interior and Iraqi Ministry of Defense

Corrosion of Aluminum Alloys in the Presence of Fire-Retardant Aircraft Interior Materials

DOT National Transportation Integrated Search

1995-10-01

This research project was to evaluate the potential for fire-retardant materials used in aircraft interiors to cause corrosion of aluminum structural alloys. Service Difficulty Reports (SDR's) were reviewed for several aircraft types, and the most fr...

On the mechanics of stress analysis of fiber-reinforced composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, V.G.

A general mathematical formulation is developed for the three-dimensional inclusion and inhomogeneity problems, which are practically important in many engineering applications such as fiber pullout of reinforced composites, load transfer behavior in the stiffened structural components, and material defects and impurities existing in engineering materials. First, the displacement field (Green's function) for an elastic solid subjected to various distributions of ring loading is derived in closed form using the Papkovich-Neuber displacement potentials and the Hankel transforms. The Green's functions are used to derive the displacement and stress fields due to a finite cylindrical inclusion of prescribed dilatational eigenstrain such asmore » thermal expansion caused by an internal heat source. Unlike an elliptical inclusion, the interior stress field in the cylindrical inclusion is not uniform. Next, the three-dimensional inhomogeneity problem of a cylindrical fiber embedded in an infinite matrix of different material properties is considered to study load transfer of a finite fiber to an elastic medium. By using the equivalent inclusion method, the fiber is modeled as an inclusion with distributed eigenstrains of unknown strength, and the inhomogeneity problem can be treated as an equivalent inclusion problem. The eigenstrains are determined to simulate the disturbance due to the existing fiber. The equivalency of elastic field between inhomogeneity and inclusion problems leads to a set of integral equations. To solve the integral equations, the inclusion domain is discretized into a finite number of sub-inclusions with uniform eigenstrains, and the integral equations are reduced to a set of algebraic equations. The distributions of eigenstrains, interior stress field and axial force along the fiber are presented for various fiber lengths and the ratio of material properties of the fiber relative to the matrix.« less

Scientific rationale for Uranus and Neptune in situ explorations

NASA Astrophysics Data System (ADS)

Mousis, O.; Atkinson, D. H.; Cavalié, T.; Fletcher, L. N.; Amato, M. J.; Aslam, S.; Ferri, F.; Renard, J.-B.; Spilker, T.; Venkatapathy, E.; Wurz, P.; Aplin, K.; Coustenis, A.; Deleuil, M.; Dobrijevic, M.; Fouchet, T.; Guillot, T.; Hartogh, P.; Hewagama, T.; Hofstadter, M. D.; Hue, V.; Hueso, R.; Lebreton, J.-P.; Lellouch, E.; Moses, J.; Orton, G. S.; Pearl, J. C.; Sánchez-Lavega, A.; Simon, A.; Venot, O.; Waite, J. H.; Achterberg, R. K.; Atreya, S.; Billebaud, F.; Blanc, M.; Borget, F.; Brugger, B.; Charnoz, S.; Chiavassa, T.; Cottini, V.; d'Hendecourt, L.; Danger, G.; Encrenaz, T.; Gorius, N. J. P.; Jorda, L.; Marty, B.; Moreno, R.; Morse, A.; Nixon, C.; Reh, K.; Ronnet, T.; Schmider, F.-X.; Sheridan, S.; Sotin, C.; Vernazza, P.; Villanueva, G. L.

2018-06-01

The ice giants Uranus and Neptune are the least understood class of planets in our solar system but the most frequently observed type of exoplanets. Presumed to have a small rocky core, a deep interior comprising ∼70% heavy elements surrounded by a more dilute outer envelope of H2 and He, Uranus and Neptune are fundamentally different from the better-explored gas giants Jupiter and Saturn. Because of the lack of dedicated exploration missions, our knowledge of the composition and atmospheric processes of these distant worlds is primarily derived from remote sensing from Earth-based observatories and space telescopes. As a result, Uranus's and Neptune's physical and atmospheric properties remain poorly constrained and their roles in the evolution of the Solar System not well understood. Exploration of an ice giant system is therefore a high-priority science objective as these systems (including the magnetosphere, satellites, rings, atmosphere, and interior) challenge our understanding of planetary formation and evolution. Here we describe the main scientific goals to be addressed by a future in situ exploration of an ice giant. An atmospheric entry probe targeting the 10-bar level, about 5 scale heights beneath the tropopause, would yield insight into two broad themes: i) the formation history of the ice giants and, in a broader extent, that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. In addition, possible mission concepts and partnerships are presented, and a strawman ice-giant probe payload is described. An ice-giant atmospheric probe could represent a significant ESA contribution to a future NASA ice-giant flagship mission.

Optimization of aircraft interior panels

NASA Technical Reports Server (NTRS)

Kourtides, Demetrius A.; Roper, Willard D.

1986-01-01

Eight different graphite composite panels were fabricated using four different resin matrices. The resin matrices included Hercules 71775, a blend of vinylpolystyrpyridine and bismaleimide, H795, a bismaleimide, Cycom 6162, a phenolic, and PSP 6022M, a polystyrylpyridine. Graphite panels were fabricated using fabric or unidirectional tape. This report describes the processes for preparing these panels and some of their mechanical, thermal and flammability properties. Panel properties are compared with state-of-the-art epoxy fiberglass composite panels.

Influence of skid trails and haul roads on understory plant richness and composition in managed forest landscapes in Upper Michigan, USA

Treesearch

David S. Buckley; Thomas R. Crow; Elizabeth A. Nauertz; Kurt E. Schulz

2003-01-01

We evaluated impacts of disturbance in interior haul roads and skid trails on understory vegetation by documenting the areal extent of these features and plant composition along 10 m x 100 m belt transects. Ten belt transects were sampled in each of three comparable northern hardwood forests under even-aged management. These forests were approximately 80 years old and...

Parameter estimation in a structural acoustic system with fully nonlinear coupling conditions

NASA Technical Reports Server (NTRS)

Banks, H. T.; Smith, Ralph C.

1994-01-01

A methodology for estimating physical parameters in a class of structural acoustic systems is presented. The general model under consideration consists of an interior cavity which is separated from an exterior noise source by an enclosing elastic structure. Piezoceramic patches are bonded to or embedded in the structure; these can be used both as actuators and sensors in applications ranging from the control of interior noise levels to the determination of structural flaws through nondestructive evaluation techniques. The presence and excitation of patches, however, changes the geometry and material properties of the structure as well as involves unknown patch parameters, thus necessitating the development of parameter estimation techniques which are applicable in this coupled setting. In developing a framework for approximation, parameter estimation and implementation, strong consideration is given to the fact that the input operator is unbonded due to the discrete nature of the patches. Moreover, the model is weakly nonlinear. As a result of the coupling mechanism between the structural vibrations and the interior acoustic dynamics. Within this context, an illustrating model is given, well-posedness and approximations results are discussed and an applicable parameter estimation methodology is presented. The scheme is then illustrated through several numerical examples with simulations modeling a variety of commonly used structural acoustic techniques for systems excitations and data collection.

Molecular Population Genetic Structure in the Piping Plover

USGS Publications Warehouse

Miller, Mark P.; Haig, Susan M.; Gratto-Trevor, Cheri L.; Mullins, Thomas D.

2009-01-01

The Piping Plover (Charadrius melodus) is a migratory shorebird currently listed as Endangered in Canada and the U.S. Great Lakes, and threatened throughout the remainder of its U.S. breeding and winter range. In this study, we undertook the first comprehensive molecular genetic-based investigation of Piping Plovers. Our primary goals were to (1) address higher level subspecific taxonomic issues, (2) characterize population genetic structure, and (3) make inferences regarding past bottlenecks or population expansions that have occurred within this species. Our analyses included samples of individuals from 23 U.S. States and Canadian Provinces, and were based on mitochondrial DNA sequences (580 bp, n = 245 individuals) and eight nuclear microsatellite loci (n = 229 individuals). Our findings illustrate strong support for separate Atlantic and Interior Piping Plover subspecies (C. m. melodus and C. m. circumcinctus, respectively). Birds from the Great Lakes region were allied with the Interior subspecies group and should be taxonomically referred to as C. m. circumcinctus. Population genetic analyses suggested that genetic structure was stronger among Atlantic birds relative to the Interior group. This pattern indicates that natal and breeding site fidelity may be reduced among Interior birds. Furthermore, analyses suggested that Interior birds have previously experienced genetic bottlenecks, whereas no evidence for such patterns existed among the Atlantic subspecies. Likewise, genetic analyses indicated that the Great Lakes region has experienced a population expansion. This finding may be interpreted as population growth following a previous bottleneck event. No genetic evidence for population expansions was found for Atlantic, Prairie Canada, or U.S. Northern Great Plains individuals. We interpret our population history insights in light of 25 years of Piping Plover census data. Overall, differences observed between Interior and Atlantic birds may reflect differences in spatiotemporal stability of Piping Plover nesting habitat between regions.

Interstellar grains within interstellar grains

NASA Technical Reports Server (NTRS)

Bernatowicz, Thomas J.; Amari, Sachiko; Zinner, Ernst K.; Lewis, Roy S.

1991-01-01

Five interstellar graphite spherules extracted from the Murchison carbonaceous meteorite are studied. The isotopic and elemental compositions of individual particles are investigated with the help of an ion microprobe, and this analysis is augmented with structural studies of ultrathin sections of the grain interiors by transmission electron microscopy. As a result, the following procedure for the formation of the interstellar graphite spherule bearing TiC crystals is inferred: (1) high-temperature nucleation and rapid growth of the graphitic carbon spherule in the atmosphere of a carbon-rich star, (2) nucleation and growth of TiC crystals during continued growth of the graphitic spherule and the accretion of TiC onto the spherule, (3) quenching of the graphite growth process by depletion of C or by isolation of the spherule before other grain types could condense.

Earth survey applications division: Research leading to the effective use of space technology in applications relating to the Earth's surface and interior

NASA Technical Reports Server (NTRS)

Carpenter, L. (Editor)

1980-01-01

Accomplishments and future plans are described for the following areas: (1) geology - geobotanical indicators and geopotential data; (2) modeling magnetic fields; (3) modeling the structure, composition, and evolution of the Earth's crust; (4) global and regional motions of the Earth's crust and earthquake occurrence; (5) modeling geopotential from satellite tracking data; (6) modeling the Earth's gravity field; (7) global Earth dynamics; (8) sea surface topography, ocean dynamics; and geophysical interpretation; (9) land cover and land use; (10) physical and remote sensing attributes important in detecting, measuring, and monitoring agricultural crops; (11) prelaunch studies using LANDSAT D; (12) the multispectral linear array; (13) the aircraft linear array pushbroom radiometer; and (14) the spaceborne laser ranging system.

An initial perspective of S-asteroid subtypes within asteroid families

NASA Technical Reports Server (NTRS)

Kelley, M. S.; Gaffey, M. J.

1993-01-01

Many main belt asteroids cluster around certain values of semi-major axis (a), inclination (i), and eccentricity (e). Hirayama was the first to notice these concentrations which he interpreted as evidence of disruptions of larger parent bodies. He called these clusters 'asteroid families'. The term 'families' is increasingly reserved for genetic associations to distinguish them from clusters of unknown or purely dynamical origin (e.g. the Phocaea cluster). Members of a genetic asteroid family represent fragments derived from various depths within the original parent planetesimal. Thus, family members offer the potential for direct examination of the interiors of parent bodies which have undergone metamorphism and differentiation similar to that occurring in the inaccessible interiors of terrestrial planets. The differentiation similar to that occurring in the inaccessible interiors of terrestrial planets. The condition that genetic family members represent the fragments of a parent object provides a critical test of whether an association (cluster in proper element space) is a genetic family. Compositions (types and relative abundances of materials) of family members must permit the reconstruction of a compositionally plausible parent body. The compositions of proposed family members can be utilized to test the genetic reality of the family and to determine the type and degree of internal differentiation within the parent planetesimal. The interpretation of the S-class mineralogy provides a preliminary evaluation of family memberships. Detailed mineralogical and petrological analysis was done based on the reflectance spectra of 39 S-type asteroids. The result is a division of the S-asteroid class into seven subtypes based on compositional differences. These subtypes, designated S(I) to S(VII), correspond to surface silicate assemblages ranging from monomineralic olivine (dunites) through olivine-pyroxene mixtures to pure pyroxene or pyroxene-feldspar mixtures (basalts). The most general conclusion is that the S-asteroids cannot be treated as a single group of objects without greatly oversimplifying their properties. Each S-subtype needs to be treated as an independent group with a distinct evolutionary history.

Preliminary Results on Lunar Interior Properties from the GRAIL Mission

NASA Technical Reports Server (NTRS)

Williams, James G.; Konopliv, Alexander S.; Asmar, Sami W.; Lemoine, H. Jay; Melosh, H. Jay; Neumann, Gregory A.; Phillips, Roger J.; Smith, David E.; Solomon, Sean C.; Watkins, Michael M.;

On implementation of the extended interior penalty function. [optimum structural design

NASA Technical Reports Server (NTRS)

Cassis, J. H.; Schmit, L. A., Jr.

1976-01-01

The extended interior penalty function formulation is implemented. A rational method for determining the transition between the interior and extended parts is set forth. The formulation includes a straightforward method for avoiding design points with some negative components, which are physically meaningless in structural analysis. The technique, when extended to problems involving parametric constraints, can facilitate closed form integration of the penalty terms over the most important parts of the parameter interval. The method lends itself well to the use of approximation concepts, such as design variable linking, constraint deletion and Taylor series expansions of response quantities in terms of design variables. Examples demonstrating the algorithm, in the context of planar orthogonal frames subjected to ground motion, are included.

Observations of Pre-Stellar Cores

NASA Astrophysics Data System (ADS)

Tafalla, M.

2005-08-01

Our understanding of the physical and chemical structure of pre-stellar cores, the simplest star-forming sites, has significantly improved since the last IAU Symposium on Astrochemistry (South Korea, 1999). Research done over these years has revealed that major molecular species like CO and CS systematically deplete onto dust grains in the interior of pre-stellar cores, while species like N2H+ and NH3 survive in the gas phase and can usually be detected toward the core centers. Such a selective behavior of molecular species gives rise to a differentiated (onion-like) chemical composition, and manifests itself in molecular maps as a dichotomy between centrally peaked and ring-shaped distributions. From the point of view of star-formation studies, the identification of molecular inhomogeneities in cores helps to resolve past discrepancies between observations made using different tracers, and brings the possibility of self-consistent modelling of the core internal structure. Here I present recent work on determining the physical and chemical structure of two pre-stellar cores, L1498 and L1517B, using observations in a large number of molecules and Monte Carlo radiative transfer analysis. These two cores are typical examples of the pre-stellar core population, and their chemical composition is characterized by the presence of large `freeze out holes' in most molecular species. In contrast with these chemically processed objects, a new population of chemically young cores has begun to emerge. The characteristics of its most extreme representative, L1521E, are briefly reviewed.

Prediction Model for Impulsive Noise on Structures

DTIC Science & Technology

2012-09-01

construction usually have an interior wall finish of: a) gypsum wallboard (also called plasterboard or drywall), b) plaster or c) wood paneling... Gypsum Plaster , Wall Board 11,67 0.04 NA For simply-supported beams vibrating in their fundamental mode, the value of KS is needed for...Dev of log10(f0) for wood panel interior to be average for wood walls with plaster or gypsum board interior. (8) L(w) based on estimated standard

InSight: Single Station Broadband Seismology for Probing Mars' Interior

NASA Technical Reports Server (NTRS)

Panning, Mark P.; Banerdt, W. Bruce; Beucler, Eric; Boschi, Lapo; Johnson, Catherine; Lognonne, Philippe; Mocquet, Antoine; Weber, Renee C.

2012-01-01

InSight is a proposed Discovery mission which will deliver a lander containing geophysical instrumentation, including a heat flow probe and a seismometer package, to Mars. The aim of this mission is to perform, for the first time, an in-situ investigation of the interior of a truly Earth- like planet other than our own, with the goal of understanding the formation and evolution of terrestrial planets through investigation of the interior structure and processes of Mars.

24 CFR 982.401 - Housing quality standards (HQS).

Code of Federal Regulations, 2010 CFR

2010-04-01

...) Elevators must be working and safe. (h) Interior air quality—(1) Performance requirement. The dwelling unit... environment; (E) Illumination and electricity; (F) Structure and materials; (G) Interior air quality; (H... dwelling unit. (e) Thermal environment—(1) Performance requirement. The dwelling unit must have and be...

Recent advances in active noise and vibration control at NASA Langley Research Center

NASA Astrophysics Data System (ADS)

Gibbs, Gary P.; Cabell, Randolph H.; Palumbo, Daniel L.; Silcox, Richard J.; Turner, Travis L.

2002-11-01

Over the past 15 years NASA has investigated the use of active control technology for aircraft interior noise. More recently this work has been supported through the Advanced Subsonic Technology Noise Reduction Program (1994-2001), High Speed Research Program (1994-1999), and through the Quiet Aircraft Technology Program (2000-present). The interior environment is recognized as an important element in flight safety, crew communications and fatigue, as well as passenger comfort. This presentation will overview research in active noise and vibration control relating to interior noise being investigated by NASA. The research to be presented includes: active control of aircraft fuselage sidewall transmission due to turbulent boundary layer or jet noise excitation, active control of interior tones due to propeller excitation of aircraft structures, and adaptive stiffening of structures for noise, vibration, and fatigue control. Work on actuator technology ranging from piezoelectrics, shape memory actuators, and fluidic actuators will be described including applications. Control system technology will be included that is experimentally based, real-time, and adaptive.

Mercury. [Mariner 10 observations and planetary properties

NASA Technical Reports Server (NTRS)

Gault, D. E.; Cassen, P.; Burns, J. A.; Strom, R. G.

1977-01-01

Information about Mercury obtained with the Mariner 10 spacecraft is summarized together with results of theoretical studies and ground-based observations. It is shown that Mercury is very likely a differentiated body, probably contains a large earthlike iron-rich core, and displays a surface similar to the moon's, which suggests a similar evolutionary history. The size and mass of Mercury are discussed along with its orbit, rotation, atmosphere, magnetic field, and magnetosphere. Surface features of Mercury are described on the basis of Mariner 10 pictures, with detailed attention given to the major physiographic provinces, the structure of the Caloris basin, the tectonic framework of the planet, crater morphology, the planet's optical and thermal properties, and cartography. The composition and structure of the interior are examined, and the thermal history of Mercury is considered. The planet's geologic history is divided into five stages or epochs: (1) accretion and differentiation, (2) terminal heavy bombardment, (3) Caloris basin formation, (4) basin flooding, and (5) postfilling lighter bombardment.

Structure Property Studies for Additively Manufactured Parts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milenski, Helen M; Schmalzer, Andrew Michael; Kelly, Daniel

2015-08-17

Since the invention of modern Additive Manufacturing (AM) processes engineers and designers have worked hard to capitalize on the unique building capabilities that AM allows. By being able to customize the interior fill of parts it is now possible to design components with a controlled density and customized internal structure. The creation of new polymers and polymer composites allow for even greater control over the mechanical properties of AM parts. One of the key reasons to explore AM, is to bring about a new paradigm in part design, where materials can be strategically optimized in a way that conventional subtractivemore » methods cannot achieve. The two processes investigated in my research were the Fused Deposition Modeling (FDM) process and the Direct Ink Write (DIW) process. The objectives of the research were to determine the impact of in-fill density and morphology on the mechanical properties of FDM parts, and to determine if DIW printed samples could be produced where the filament diameter was varied while the overall density remained constant.« less

Elasticity of Deep-Earth Materials at High P and T: Implication for Earths Lower Mantle

NASA Astrophysics Data System (ADS)

Bass, Jay; Sinogeikin, S. V.; Mattern, Estelle; Jackson, J. M.; Matas, J.; Wang, J.; Ricard, Y.

2005-03-01

Brillouin spectroscopy allows measurements of sound velocities and elasticity on phases of geophysical interest at high Pressures and Temperatures. This technique was used to measure the properties of numerous important phases of Earths deep interior. Emphasis is now on measurements at elevated P-T conditions, and measurements on dense polycrystals. Measurements to 60 GPa were made using diamond anvil cells. High temperature is achieved by electrical resistance and laser heating. Excellent results are obtained for polycrystalline samples of dense oxides such as silicate spinels, and (Mg,Al)(Si,Al)O3 --perovskites. A wide range of materials can now be characterized. These and other results were used to infer Earths average lower mantle composition and thermal structure by comparing mineral properties at lower mantle P-T conditions to global Earth models. A formal inversion procedure was used. Inversions of density and bulk sound velocity do not provide robust compositional and thermal models. Including shear properties in the inversions is important to obtain unique solutions. We discuss the range of models consistent with present lab results, and data needed to further refine lower mantle models.

Engineering CNDP's of dendrimers containing phosphorous interior compositions to produce new emerging properties

NASA Astrophysics Data System (ADS)

Caminade, Anne-Marie; Majoral, Jean-Pierre

2018-03-01

Phosphorus-containing dendrimers are defined as dendrimers having at least one phosphorus atom at each branching point. In this review, we will show how phosphorhydrazone dendrimers can be modified at will at the level of the core and of the branches, to afford specific properties, such as fluorescence to image biological events. Accelerated methods of synthesis of phosphorus (one step for one generation) will be also displayed, as well as the specific reactivity of P=N-P=S linkages obtained in most of these accelerated method of synthesis, which has led to particularly original dendritic architectures, such as dendrons included in dendrimers. Finally, we will display how modifications of the internal structure of a series of dendrimers having the same type and number of terminal functions can deeply modify their biological anti-inflammatory properties. Among the six critical nanoscale design parameters (CNDP), we will show how two of them, i.e., architecture and elemental composition, have been particularly engineered to modify phosphorus-containing dendrimers, in order to fulfill the desired properties.

KSC-05PD-0001

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. The Deep Impact spacecraft waits at Astrotech Space Operations in Titusville, Fla., for placement of a protective cover before the canister is installed around it. Once the spacecraft is completely covered, it will be transferred to Launch Pad 17-B on Cape Canaveral Air Force Station, Fla. Then, in the mobile service tower, the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0004

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. At Astrotech Space Operations in Titusville, Fla., Boeing technicians place the lower segments of a protective canister around the Deep Impact spacecraft. Once the spacecraft is completely covered, it will be transferred to Launch Pad 17-B on Cape Canaveral Air Force Station, Fla. Then, in the mobile service tower, the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0007

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. At Astrotech Space Operations in Titusville, Fla., technicians lower the upper canister toward the Deep Impact spacecraft. It will be attached to the lower segments already surrounding the spacecraft. Once the spacecraft is completely covered, it will be transferred to Launch Pad 17-B on Cape Canaveral Air Force Station, Fla. Then, in the mobile service tower, the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0005

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. At Astrotech Space Operations in Titusville, Fla., Boeing technicians roll the Deep Impact spacecraft into another area where the upper canister can be lowered around it. Once the spacecraft is completely covered, it will be transferred to Launch Pad 17-B on Cape Canaveral Air Force Station, Fla. Then, in the mobile service tower, the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0002

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. At Astrotech Space Operations in Titusville, Fla., a protective cover is being lowered over the Deep Impact spacecraft to protect it before the canister is installed around it. Once the spacecraft is completely covered, it will be transferred to Launch Pad 17-B on Cape Canaveral Air Force Station, Fla. Then, in the mobile service tower, the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0011

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. The Deep Impact spacecraft leaves Astrotech Space Operations in Titusville, Fla., in the pre-dawn hours on a journey to Launch Pad 17-B at Cape Canaveral Air Force Station, Fla. There the spacecraft will be attached to the second stage of the Boeing Delta II rocket. Next the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch and ascent. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0003

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. At Astrotech Space Operations in Titusville, Fla., Boeing technicians lower a protective cover over the Deep Impact spacecraft to protect it before the canister is installed around it. Once the spacecraft is completely covered, it will be transferred to Launch Pad 17-B on Cape Canaveral Air Force Station, Fla. Then, in the mobile service tower, the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3- foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0006

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. At Astrotech Space Operations in Titusville, Fla., technicians install a crane onto the upper canister before lifting it to install around the Deep Impact spacecraft. Once the spacecraft is completely covered, it will be transferred to Launch Pad 17-B on Cape Canaveral Air Force Station, Fla. Then, in the mobile service tower, the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0009

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. At Astrotech Space Operations in Titusville, Fla., Boeing technicians attach the upper canister with the lower segments surrounding the Deep Impact spacecraft. Once the spacecraft is completely covered, it will be transferred to Launch Pad 17-B on Cape Canaveral Air Force Station, Fla. Then, in the mobile service tower, the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0008

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. At Astrotech Space Operations in Titusville, Fla., technicians lower the upper canister toward the Deep Impact spacecraft. It will be attached to the lower segments already surrounding the spacecraft. Once the spacecraft is completely covered, it will be transferred to Launch Pad 17-B on Cape Canaveral Air Force Station, Fla. Then, in the mobile service tower, the fairing will be installed around the spacecraft. The fairing is a molded structure that fits flush with the outside surface of the Delta II upper stage booster and forms an aerodynamically smooth joint, protecting the spacecraft during launch. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will reveal the secrets of its interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

Kuiper Belt Objects of different sizes and average densities: thermal evolution scenarios and modern structure of matter

NASA Astrophysics Data System (ADS)

Shchuko, O. B.; Shchuko, S. D.; Kartashov, D.; Orosei, R.

2012-04-01

Thermal evolution of accretion-formed Kuiper Belt Objects (KBOs) with modern sizes from 200 to 2000 km and average densities from 1100 to 3200 kg/m3 has been studied by mathematical simulation methods. The values range of physical parameters of the accretion material and ultimate radionuclide content, securing KBO existence at present, have been found. The solid dust material of protosolar cloud fringe regions and fine-fractured H2O condensate in the form of amorphous ice are considered to have been the building matter for these objects. This material was represented by small dust particles of different chemical and mineralogical composition, embedded with radionuclides 238U, 235U, 232Th, 40K providing the sources of radiogenic heat. H2O condensate secured the presence of amorphous ice in the forming body's matter. Radiogenic heat leads to H2O phase transitions which define a body's interior matter differentiation. The radionuclide content at the initial time of the body formation determined the dynamically changing degree of the interior matter differentiation at different KBO depths for the whole period from the initial up to the present time. For the models of the celestial objects considered, the dynamically changing boundaries of spherically symmetric regions with different degree of matter differentiation have been determined.

State-of-the-art of the Space Shuttle External Tank

NASA Astrophysics Data System (ADS)

Ronquillo, L.

The designation, structure and environment of the External Tank (ET) of the Space Shuttle as well as plans for increasing the facilities and tooling to meet the required production rate capability of 40 or more ETs per year in 1992 are described. Special attention is given to the weight reduction of ET, since 1.0 lb of weight saved on the empty structure translates into about 0.9 lb of additional payload. To determine the potentiality of the weight reduction, structural tests were conducted. It was found that the tank could function properly with interior support structures reduced, and selected stringers eliminated. It is reported that an alternate sprayable polyisocyanurate foam capable of replacing a foam insulation over ablator bilayer thermoprotective composite on the aft-dome of the tank was developed: a commercially available material was modified to adhere to the -423 F aluminum substrate in the 2000 F engine-plume radiant-heat environment. It is mentioned that the weight savings program which started in Oct. 1975 saved 6000 lb by Jan. 1979. To reduce weld testing time and gain 100 times the accuracy, an electromechanical check system was developed. Problems of using robots are discussed.

Mould design and manufacturing considerations of honeycomb biocomposites with transverse fibre direction for aerospace application

NASA Astrophysics Data System (ADS)

Manan, N. H.; Majid, D. L.; Romli, F. I.

2016-10-01

Sandwich structures with honeycomb core are known to significantly improve stiffness at lower weight and possess high flexural rigidity. They have found wide applications in aerospace as part of the primary structures, as well as the interior paneling and floors. High performance aluminum and aramid are the typical materials used for the purpose of honeycomb core whereas in other industries, materials such as fibre glass, carbon fibre, Nomex and also Kevlar reinforced with polymer are used. Recently, growing interest in developing composite structures with natural fibre reinforcement has also spurred research in natural fibre honeycomb material. The majority of the researches done, however, have generally emphasized on the usage of random chopped fibre and only a few are reported on development of honeycomb structure using unidirectional fibre as the reinforcement. This is mainly due to its processing difficulties, which often involve several stages to account for the arrangement of fibres and curing. Since the use of unidirectional fibre supports greater strength compared to random chopped fibre, a single-stage process in conjunction with vacuum infusion is suggested with a mould design that supports fibre arrangement in the direction of honeycomb loading.

Paleozoic-involving thrust array in the central Sierras Interiores (South Pyrenean Zone, Central Pyrenees): regional implications

NASA Astrophysics Data System (ADS)

Rodriguez, L.; Cuevas, J.; Tubía, J. M.

2012-04-01

This work deals with the structural evolution of the Sierras Interiores between the Tena and Aragon valleys. The Sierras Interiores is a WNW-trending mountain range that bounds the South Pyrenean Zone to the north and that is characterized by a thrust-fold system with a strong lithological control that places preferably decollements in Triassic evaporites. In the studied area of the Sierras Interiores Cenomanian limestones cover discordantly the Paleozoic rocks of the Axial Zone because there is a stratigraphic lacuna developed from Triassic to Late Cretaceous times. A simple lithostratigraphy of the study area is made up of Late Cenomanian to Early Campanian limestones with grey colour and massive aspect in landscape (170 m, Lower calcareous section), Campanian to Maastrichtian brown coloured sandstones (400-600 m, Marboré sandstones) and, finally, Paleocene light-coloured massive limestones (130-230 m), that often generate the higher topographic levels of the Sierras Interiores due to their greater resistance to erosion. Above the sedimentary sequence of the Sierras Interiores, the Jaca Basin flysch succession crops out discordantly. Based on a detailed mapping of the studied area of the Sierras Interiores, together with well and structural data of the Jaca Basin (Lanaja, 1987; Rodríguez and Cuevas, 2008) we have constructed a 12 km long NS cross section, approximately parallel to the movement direction deduced for this region (Rodríguez et al., 2011). The main structure is a thrust array made up of at least four Paleozoic-involving thrusts (the deeper thrust system) of similar thickness in a probably piggyback sequence, some of which are blind thrusts that generate fold-propagation-folds in upper levels. The higher thrust of the thrust array crops out duplicating the lower calcareous section all over the Sierras Interiores. The emplacement of the deeper thrust system generated the tightness of previous structures: south directed piggyback duplexes (the upper thrust system) affecting the Marboré sandstones and the Paleocene limestones, deformed by angular south-vergent folds and their related axial plane foliation. The transect explained above clearly summarizes the alpine evolution of northern part of the Sierras Interiores. Moreover, well data available indicate the presence of two thrust soled in the lower calcareous section covering Triassic evaporites at 5 km depth and 8 km to the south of the Sierras Interiores. Because the Triassic evaporites constitute a main decollement level in the South Pyrenean Zone, the deeper thrust system is associated to the emplacement of the Gavarnie nappe. Lanaja, J.M., 1987, Contribución de la exploración petrolífera al conocimiento de la Geología de España, IGME, Madrid, 465 p. Rodríguez, L., Cuevas, J., 2008. Geogaceta 44, 51-54. Rodríguez, L., Cuevas, J., Tubia, J.M., 2011. Geophysical Research Abstracts 13, 2273.