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Sample records for active dust lifting

  1. The Mars Dust Cycle: Investigating the Effects of Radiatively Active Water Ice Clouds on Surface Stresses and Dust Lifting Potential with the NASA Ames Mars General Circulation Model

    NASA Technical Reports Server (NTRS)

    Kahre, Melinda A.; Hollingsworth, Jeffery

    2012-01-01

    The dust cycle is a critically important component of Mars' current climate system. Dust is present in the atmosphere of Mars year-round but the dust loading varies with season in a generally repeatable manner. Dust has a significant influence on the thermal structure of the atmosphere and thus greatly affects atmospheric circulation. The dust cycle is the most difficult of the three climate cycles (CO2, water, and dust) to model realistically with general circulation models. Until recently, numerical modeling investigations of the dust cycle have typically not included the effects of couplings to the water cycle through cloud formation. In the Martian atmosphere, dust particles likely provide the seed nuclei for heterogeneous nucleation of water ice clouds. As ice coats atmospheric dust grains, the newly formed cloud particles exhibit different physical and radiative characteristics. Thus, the coupling between the dust and water cycles likely affects the distributions of dust, water vapor and water ice, and thus atmospheric heating and cooling and the resulting circulations. We use the NASA Ames Mars GCM to investigate the effects of radiatively active water ice clouds on surface stress and the potential for dust lifting. The model includes a state-of-the-art water ice cloud microphysics package and a radiative transfer scheme that accounts for the radiative effects of CO2 gas, dust, and water ice clouds. We focus on simulations that are radiatively forced by a prescribed dust map, and we compare simulations that do and do not include radiatively active clouds. Preliminary results suggest that the magnitude and spatial patterns of surface stress (and thus dust lifting potential) are substantial influenced by the radiative effects of water ice clouds.

  2. Particle Lifting Processes in Dust Devils

    NASA Astrophysics Data System (ADS)

    Neakrase, L. D. V.; Balme, M. R.; Esposito, F.; Kelling, T.; Klose, M.; Kok, J. F.; Marticorena, B.; Merrison, J.; Patel, M.; Wurm, G.

    2016-10-01

    Particle lifting in dust devils on both Earth and Mars has been studied from many different perspectives, including how dust devils could influence the dust cycles of both planets. Here we review our current understanding of particle entrainment by dust devils by examining results from field observations on Earth and Mars, laboratory experiments (at terrestrial ambient and Mars-analog conditions), and analytical modeling. By combining insights obtained from these three methodologies, we provide a detailed overview on interactions between particle lifting processes due to mechanical, thermal, electrodynamical and pressure effects, and how these processes apply to dust devils on Earth and Mars. Experiments and observations have shown dust devils to be effective lifters of dust given the proper conditions on Earth and Mars. However, dust devil studies have yet to determine the individual roles of each of the component processes acting at any given time in dust devils.

  3. Coupling Mars' Dust and Water Cycles: Effects on Dust Lifting Vigor, Spatial Extent and Seasonality

    NASA Technical Reports Server (NTRS)

    Kahre, M. A.; Hollingsworth, J. L.; Haberle, R. M.; Montmessin, F.

    2012-01-01

    The dust cycle is an important component of Mars' current climate system. Airborne dust affects the radiative balance of the atmosphere, thus greatly influencing the thermal and dynamical state of the atmosphere. Dust raising events on Mars occur at spatial scales ranging from meters to planet-wide. Although the occurrence and season of large regional and global dust storms are highly variable from one year to the next, there are many features of the dust cycle that occur year after year. Generally, a low-level dust haze is maintained during northern spring and summer, while elevated levels of atmospheric dust occur during northern autumn and winter. During years without global-scale dust storms, two peaks in total dust loading were observed by MGS/TES: one peak occurred before northern winter solstice at Ls 200-240, and one peak occurred after northern winter solstice at L(sub s) 305-340. These maxima in dust loading are thought to be associated with transient eddy activity in the northern hemisphere, which has been observed to maximize pre- and post-solstice. Interactive dust cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active dust. Although the predicted global dust loadings from these simulations capture some aspects of the observed dust cycle, there are marked differences between the simulated and observed dust cycles. Most notably, the maximum dust loading is robustly predicted by models to occur near northern winter solstice and is due to dust lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in dust loading. Interactive dust cycle studies typically have not included the formation of water ice clouds or their radiative effects. Water ice clouds can influence the dust cycle by scavenging dust from atmosphere and by interacting with solar and infrared radiation

  4. Investigating the Effects of Water Ice Cloud Radiative Forcing on the Predicted Patterns and Strength of Dust Lifting on Mars

    NASA Astrophysics Data System (ADS)

    Kahre, Melinda A.; Hollingsworth, Jeffery L.; Haberle, Robert M.

    2014-11-01

    The dust cycle is critical for the current Mars climate system because airborne dust significantly influences the thermal and dynamical structure of the atmosphere. The atmospheric dust loading varies with season and exhibits variability on a range of spatial and temporal scales. Until recently, interactive dust cycle modeling studies that include the lifting, transport, and sedimentation of radiatively active dust have not included the formation or radiative effects of water ice clouds. While the simulated patterns of dust lifting and global dust loading from these investigations of the dust cycle in isolation reproduce some characteristics of the observed dust cycle, there are also marked differences between the predictions and the observations. Water ice clouds can influence when, where, and how much dust is lifted from the surface by altering the thermal structure of the atmosphere and the character and strength of the general circulation. Using an updated version of the NASA Ames Mars Global Climate Model (GCM), we show that including water ice cloud formation and their radiative effects affect the magnitude and spatial extent of dust lifting, particularly in the northern hemisphere during the pre- and post- winter solstitial seasons. Feedbacks between dust lifting, cloud formation, circulation intensification and further dust lifting are isolated and shown to be important for improving the behavior of the simulated dust cycle.

  5. A solar escalator on Mars: Self-lifting of dust layers by radiative heating

    NASA Astrophysics Data System (ADS)

    Daerden, F.; Whiteway, J. A.; Neary, L.; Komguem, L.; Lemmon, M. T.; Heavens, N. G.; Cantor, B. A.; Hébrard, E.; Smith, M. D.

    2015-09-01

    Dust layers detected in the atmosphere of Mars by the light detection and ranging (LIDAR) instrument on the Phoenix Mars mission are explained using an atmospheric general circulation model. The layers were traced back to observed dust storm activity near the edge of the north polar ice cap where simulated surface winds exceeded the threshold for dust lifting by saltation. Heating of the atmospheric dust by solar radiation caused buoyant instability and mixing across the top of the planetary boundary layer (PBL). Differential advection by wind shear created detached dust layers above the PBL that ascended due to radiative heating and arrived at the Phoenix site at heights corresponding to the LIDAR observations. The self-lifting of the dust layers is similar to the "solar escalator" mechanism for aerosol layers in the Earth's stratosphere.

  6. Simulating Mars' Dust Cycle with a Mars General Circulation Model: Effects of Water Ice Cloud Formation on Dust Lifting Strength and Seasonality

    NASA Technical Reports Server (NTRS)

    Kahre, Melinda A.; Haberle, Robert; Hollingsworth, Jeffery L.

    2012-01-01

    The dust cycle is critically important for the current climate of Mars. The radiative effects of dust impact the thermal and dynamical state of the atmosphere [1,2,3]. Although dust is present in the Martian atmosphere throughout the year, the level of dustiness varies with season. The atmosphere is generally the dustiest during northern fall and winter and the least dusty during northern spring and summer [4]. Dust particles are lifted into the atmosphere by dust storms that range in size from meters to thousands of kilometers across [5]. Regional storm activity is enhanced before northern winter solstice (Ls200 degrees - 240 degrees), and after northern solstice (Ls305 degrees - 340 degrees ), which produces elevated atmospheric dust loadings during these periods [5,6,7]. These pre- and post- solstice increases in dust loading are thought to be associated with transient eddy activity in the northern hemisphere with cross-equatorial transport of dust leading to enhanced dust lifting in the southern hemisphere [6]. Interactive dust cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active dust. Although the predicted global dust loadings from these simulations capture some aspects of the observed dust cycle, there are marked differences between the simulated and observed dust cycles [8,9,10]. Most notably, the maximum dust loading is robustly predicted by models to occur near northern winter solstice and is due to dust lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in dust loading.

  7. A theoretical note on aerodynamic lifting in dust devils

    NASA Astrophysics Data System (ADS)

    Wang, Zhen-Ting

    2016-02-01

    The stress distribution of a known rotating flow near the ground in fluid mechanics indicates that the horizontal aerodynamic entrainment of particles within dust devils is attributed to friction force rather than pressure force. The expression of dust emission rate on Earth was theoretically discussed based on simulated flow field and our current understanding of the physics of aeolian dust. It seems that transition flow is vital to dust devils on Mars.

  8. An assessment of the impact of local processes on dust lifting in martian climate models

    NASA Astrophysics Data System (ADS)

    Mulholland, David P.; Spiga, Aymeric; Listowski, Constantino; Read, Peter L.

    2015-05-01

    Simulation of the lifting of dust from the planetary surface is of substantially greater importance on Mars than on Earth, due to the fundamental role that atmospheric dust plays in the former's climate, yet the dust emission parameterisations used to date in martian global climate models (MGCMs) lag, understandably, behind their terrestrial counterparts in terms of sophistication. Recent developments in estimating surface roughness length over all martian terrains and in modelling atmospheric circulations at regional to local scales (less than O(100 km)) presents an opportunity to formulate an improved wind stress lifting parameterisation. We have upgraded the conventional scheme by including the spatially varying roughness length in the lifting parameterisation in a fully consistent manner (thereby correcting a possible underestimation of the true threshold level for wind stress lifting), and used a modification to account for deviations from neutral stability in the surface layer. Following these improvements, it is found that wind speeds at typical MGCM resolution never reach the lifting threshold at most gridpoints: winds fall particularly short in the southern midlatitudes, where mean roughness is large. Sub-grid scale variability, manifested in both the near-surface wind field and the surface roughness, is then considered, and is found to be a crucial means of bridging the gap between model winds and thresholds. Both forms of small-scale variability contribute to the formation of dust emission 'hotspots': areas within the model gridbox with particularly favourable conditions for lifting, namely a smooth surface combined with strong near-surface gusts. Such small-scale emission could in fact be particularly influential on Mars, due both to the intense positive radiative feedbacks that can drive storm growth and a strong hysteresis effect on saltation. By modelling this variability, dust lifting is predicted at the locations at which dust storms are frequently

  9. Microbial hitchhikers on intercontinental dust: catching a lift in Chad

    PubMed Central

    Favet, Jocelyne; Lapanje, Ales; Giongo, Adriana; Kennedy, Suzanne; Aung, Yin-Yin; Cattaneo, Arlette; Davis-Richardson, Austin G; Brown, Christopher T; Kort, Renate; Brumsack, Hans-Jürgen; Schnetger, Bernhard; Chappell, Adrian; Kroijenga, Jaap; Beck, Andreas; Schwibbert, Karin; Mohamed, Ahmed H; Kirchner, Timothy; de Quadros, Patricia Dorr; Triplett, Eric W; Broughton, William J; Gorbushina, Anna A

    2013-01-01

    Ancient mariners knew that dust whipped up from deserts by strong winds travelled long distances, including over oceans. Satellite remote sensing revealed major dust sources across the Sahara. Indeed, the Bodélé Depression in the Republic of Chad has been called the dustiest place on earth. We analysed desert sand from various locations in Chad and dust that had blown to the Cape Verde Islands. High throughput sequencing techniques combined with classical microbiological methods showed that the samples contained a large variety of microbes well adapted to the harsh desert conditions. The most abundant bacterial groupings in four different phyla included: (a) Firmicutes—Bacillaceae, (b) Actinobacteria—Geodermatophilaceae, Nocardiodaceae and Solirubrobacteraceae, (c) Proteobacteria—Oxalobacteraceae, Rhizobiales and Sphingomonadaceae, and (d) Bacteroidetes—Cytophagaceae. Ascomycota was the overwhelmingly dominant fungal group followed by Basidiomycota and traces of Chytridiomycota, Microsporidia and Glomeromycota. Two freshwater algae (Trebouxiophyceae) were isolated. Most predominant taxa are widely distributed land inhabitants that are common in soil and on the surfaces of plants. Examples include Bradyrhizobium spp. that nodulate and fix nitrogen in Acacia species, the predominant trees of the Sahara as well as Herbaspirillum (Oxalobacteraceae), a group of chemoorganotrophic free-living soil inhabitants that fix nitrogen in association with Gramineae roots. Few pathogenic strains were found, suggesting that African dust is not a large threat to public health. PMID:23254516

  10. Microbial hitchhikers on intercontinental dust: catching a lift in Chad.

    PubMed

    Favet, Jocelyne; Lapanje, Ales; Giongo, Adriana; Kennedy, Suzanne; Aung, Yin-Yin; Cattaneo, Arlette; Davis-Richardson, Austin G; Brown, Christopher T; Kort, Renate; Brumsack, Hans-Jürgen; Schnetger, Bernhard; Chappell, Adrian; Kroijenga, Jaap; Beck, Andreas; Schwibbert, Karin; Mohamed, Ahmed H; Kirchner, Timothy; de Quadros, Patricia Dorr; Triplett, Eric W; Broughton, William J; Gorbushina, Anna A

    2013-04-01

    Ancient mariners knew that dust whipped up from deserts by strong winds travelled long distances, including over oceans. Satellite remote sensing revealed major dust sources across the Sahara. Indeed, the Bodélé Depression in the Republic of Chad has been called the dustiest place on earth. We analysed desert sand from various locations in Chad and dust that had blown to the Cape Verde Islands. High throughput sequencing techniques combined with classical microbiological methods showed that the samples contained a large variety of microbes well adapted to the harsh desert conditions. The most abundant bacterial groupings in four different phyla included: (a) Firmicutes-Bacillaceae, (b) Actinobacteria-Geodermatophilaceae, Nocardiodaceae and Solirubrobacteraceae, (c) Proteobacteria-Oxalobacteraceae, Rhizobiales and Sphingomonadaceae, and (d) Bacteroidetes-Cytophagaceae. Ascomycota was the overwhelmingly dominant fungal group followed by Basidiomycota and traces of Chytridiomycota, Microsporidia and Glomeromycota. Two freshwater algae (Trebouxiophyceae) were isolated. Most predominant taxa are widely distributed land inhabitants that are common in soil and on the surfaces of plants. Examples include Bradyrhizobium spp. that nodulate and fix nitrogen in Acacia species, the predominant trees of the Sahara as well as Herbaspirillum (Oxalobacteraceae), a group of chemoorganotrophic free-living soil inhabitants that fix nitrogen in association with Gramineae roots. Few pathogenic strains were found, suggesting that African dust is not a large threat to public health.

  11. The effect of dust lifting process on the electrical properties of the atmosphere

    NASA Astrophysics Data System (ADS)

    Esposito, Francesca; Molinaro, Roberto; Ionut Popa, Ciprian; Molfese, Cesare; Cozzolino, Fabio; Marty, Laurent; Taj-Eddine, Kamal; Di Achille, Gaetano; Silvestro, Simone; Ori, Gian Gabriele

    2015-04-01

    Airborne dust and aerosol particles affect climate by absorbing and scattering thermal and solar radiation and acting as condensation nuclei for the formation of clouds. So, they strongly influence the atmospheric thermal structure, balance and circulation. On Earth and Mars, this 'climate forcing' is one of the most uncertain processes in climate change predictions. Wind-driven blowing of sand and dust is also responsible for shaping planetary surfaces through the formation of sand dunes and ripples, the erosion of rocks, and the creation and transport of soil particles. These processes are not confined to Earth, but occur also on Mars, Venus and Titan. It is clear that the knowledge of the atmospheric dust properties and the mechanisms of dust settling and raising into the atmosphere are important to understand planetary climate and surface evolution. On Mars the physical processes responsible for dust injection into the atmosphere are still poorly understood, but they likely involve saltation as on Earth. Saltation is a process where large sand grains are forced by the wind to move in ballistic trajectories on the soil surface. During these hops they hit dust particles, that are well bound to the soil due to interparticle cohesive forces, thus transferring to them the momentum necessary to be entrained into the atmosphere. Recently, it has been shown that this process is also responsible to generate strong electric fields in the atmosphere up to 100-150 kV/m. This enhanced electric force acts as a feedback in the dust lifting process, lowering the threshold of the wind friction velocity u* necessary to initiate sand saltation. It is an important aspect of dust lifting process that need to be well characterized and modeled. Even if literature reports several measurements of E-fields in dust devils events, very few reports deal with atmospheric electric properties during dust storms or isolated gusts. We present here preliminary results of an intense field test

  12. Experimental and numerical investigation into the dynamics of dust lifting up from the layer behind the propagating shock wave

    NASA Astrophysics Data System (ADS)

    Klemens, R.; Oleszczak, P.; Zydak, P.

    2013-05-01

    In a number of industrial facilities and factory buildings dust layers cover floors, walls, ceilings and various installations. The dust can be easily dispersed by pressure waves generated by weak explosions or as a result of damage of a compressed gas systems. If the obtained explosive dust-air mixture is ignited, a devastating explosion may occur. The aim of the work was to study the dust lifting process from the layer behind the propagating shock wave and to determine some important parameters, which later could be used for development and validation of the numerical model of the process. The experiments were conducted with the use of a shock tube. For measuring the dust concentration in the mixture with air, a special five-channel optical device was constructed, enabling measurements at five positions located in one vertical plane along the height of the tube. The delay in lifting of the dust from the layer and the vertical velocity of the dust cloud were calculated from the dust concentration measurements. The research was carried out for various initial conditions and for various types of dusts. The results obtained in tests with black coal dust are presented in the paper. Three shock wave velocities: 450, 490 and 518 m/s and three dust layer thicknesses, equal to 1.0, 1.5 and 2.0 mm, were taken into consideration. Measurements results of the mean vertical component of the dust cloud velocity between the layer and the first laser beam were used in a new model, where the dust dispersing process is modeled as an injection of the dust from the layer. The numerical simulations were based on the Euler or Lagrange model of the dust phase. In case of Euler model, the dust layer was replaced by injection of dust from the bottom of the channel. The calculations were performed for two models of the investigated process. In the first model, correlation was worked out for all tested dusts and in the new model, the individual correlations for every tested dust were

  13. Sahelian dust lifting in the inter-tropical discontinuity region: Lidar observations and mesoscale modelling

    NASA Astrophysics Data System (ADS)

    Bou Karam, D.; Flamant, C.; Tulet, P.; Chaboureau, J.; Dabas, A.; Chong, M.; Reitebuch, O.

    2007-12-01

    Airbone lidar observations acquired with the LEANDRE 2 system during 3 flights of the SAFIRE Falcon 20 in the framework of the AMMA Special Observing Period (SOP) 2a1 (July 2006) over western Niger, revealed the existence of desert dust uptakes in the region of the inter-tropical discontinuity (ITD) in the morning hours. Complementary observations provided by dropsondes released from the same platform as well as airborne wind measurements made from another platform (the DLR Falcon 20, flying in coordination with the SAFIRE Falcon 20) evidenced that the lifting was associated with the leading edge of the monsoon low level jet, and to be transported southward by the harmattan, above the monsoon layer. A 10-day numerical simulation, using the mesoscale model Meso-NH (including the dust emission box Dust Entrainment And Deposition model), was conducted to assess the representativity of the observed phenomenon as well as the mechanisms associated with the Sahelian dust emissions. The Meso-NH simulation (initialized by and nudged with ECMWF analyses) was carried out on a 2000 km x 2000 km domain (20-km horizontal resolution) centered at 20°N and 7°E, that included the Falcons flight track, as well as numerous AMMA-related ground-based measurement sites (Tamanrasset, Agadez, Niamey/Banizoumbou, etc..) for validation purposes. In the simulation, large dust uptakes associated with the leading edge of the monsoon flow, with a dust concentration reaching 2000μg/m3, and to be transported southward by the harmattan, above the monsoon layer, were well reproduced. On the other hand, the simulation suggested the existence of dust emissions associated with the harmattan flow which were not observed by airborne lidar measurements. The reason for the discrepancy between the model results and the lidar observations is investigated.

  14. Superficial shoulder muscle co-activations during lifting tasks: Influence of lifting height, weight and phase.

    PubMed

    Blache, Y; Dal Maso, F; Desmoulins, L; Plamondon, A; Begon, M

    2015-04-01

    This study aimed to assess the level of co-activation of the superficial shoulder muscles during lifting movement. Boxes containing three different loads (6, 12, and 18 kg) were lifted by fourteen subjects from the waist to shoulder or eye level. The 3D kinematics and electromyograms of the three deltoids, latissimus dorsi and pectoralis major were recorded. A musculoskeletal model was used to determine direction of the moment arm of these muscles. Finally an index of muscle co-activation named the muscle focus was used to evaluate the effects of lifting height, weight lifted and phase (pulling, lifting and dropping phases) on superficial shoulder muscle coactivation. The muscle focus was lower (more co-contraction) during the dropping phase compared to the two other phases (-13%, p<0.001). This was explained by greater muscle activations and by a change in the direction of the muscle moment arm as a function of glenohumeral joint position. Consequently, the function of the shoulder superficial muscles varied with respect to the glenohumeral joint position. To increase the superficial muscle coactivation during the dropping phase may be a solution to increase glenohumeral joint stiffness.

  15. Dust loading in Gusev crater, Mars: Results from two active dust devil seasons

    NASA Astrophysics Data System (ADS)

    Waller, D. A.; Greeley, R.; Neakrase, L. D.; Landis, G. A.; Whelley, P.; Thompson, S. D.

    2009-12-01

    Dust devils dominate the volcanic plains at the Mars Exploration Rover (MER) landing site within the Low Albedo Zone (LAZ) in Gusev Crater. Previous studies indicate that the inferred pressure drop within the dust devil core allows the vortex to lift large amounts of unconsolidated dust high into the atmosphere which contributes to the atmospheric haze. Previous laboratory results indicate that dust devils are efficient in lifting very fine-grained (<10 μm) material, even when boundary layer winds do not exceed previously predicted threshold wind speeds (~30-35 m/s at 1.5 m above the surface for Mars conditions). Since landing in Gusev crater in January 2004, MER Spirit has obtained data for two dust devil seasons (defined as the period of time when the first and last dust devils were imaged), with a third season currently being analyzed. These seasons typically correspond to southern spring and summer, when winds capable of lifting sediment are determined to be most frequent. All observations for Season One were taken as Spirit neared the summit of Husband Hill. During Season Two Spirit imaged dust devils in the plains as it traversed within the Inner Basin, a low-lying area in the Columbia Hills complex. All results were extrapolated so that they are representative of the entire LAZ. Season One lasted 270 sols (March 2005 to December 2005 corresponding to Ls 173.2 to 339.5 degrees), whereas Season Two lasted 153 sols (January 2007 to June 2007 corresponding to Ls 171.2 to 266.7 degrees) and ended suddenly on sol 1240 just after the dust devil frequency peaked for the season. This abrupt drop in dust devil activity corresponded to atmospheric opacity levels that exceeded 1.0 and the onset of a global dust storm that originated in the southern hemisphere that engulfed Gusev within weeks. Results show a large contrast in activity between the two seasons. An 81% decrease in dust devil frequency across the plains was found in Season Two. 533 dust devils were imaged

  16. Dust Telescopes and Active Dust Collectors: Linking Dust to Their Sources

    NASA Astrophysics Data System (ADS)

    Drake, K. J.; Sternovsky, Z.; Gruen, E.; Srama, R.; Auer, S.; Horanyi, M.; Kempf, S.; Krueger, H.; Postberg, F.

    2010-12-01

    Cosmic dust particles from remote sites and times are treasures of information. By determining the dust particles' source and their elemental properties, we can learn about the environments, where they were formed and processed. Born as stardust in the cool atmospheres of giant stars or in novae and supernovae explosions, the particles are subsequently modified in the interstellar medium. Interplanetary dust that originates from comets and asteroids represents even more processed material at different stages of Solar System evolution. Interstellar and interplanetary dust particles from various sources can be detected and analyzed in the near-Earth space environment. The newly developed instruments Dust Telescope and Active Dust Collector are able to determine the origin of dust particles and provide their elemental composition. A Dust Telescope is a combination of a Dust Trajectory Sensor (DTS) [1] 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 when a charged grain flies through a position sensitive electrode system. A modern DTS can measure dust particles as small as 0.2 µm in radius and dust speeds up to 100 km/s. 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 up to >100 [2]. The advanced Dust Telescope is capable of identifying interstellar and interplanetary grains, and measuring their mass, velocity vector, charge, elemental and isotopic compositions. An Active Dust Collector combines a DTS with an aerogel or other dust collector materials, e.g. like the ones used on the Stardust mission. The combination of a DTS with a dust collector provides not only individual trajectories of the collected particles but also their impact time and position on the collector which proves essential to

  17. Active Tailoring of Lift Distribution to Enhance Cruise Performance

    NASA Technical Reports Server (NTRS)

    Flamm, Jeffrey D. (Technical Monitor); Pfeiffer, Neal J.; Christians, Joel G.

    2005-01-01

    During Phase I of this project, Raytheon Aircraft Company (RAC) has analytically and experimentally evaluated key components of a system that could be implemented for active tailoring of wing lift distribution using low-drag, trailing-edge modifications. Simple systems such as those studied by RAC could be used to enhance the cruise performance of a business jet configuration over a range of typical flight conditions. The trailing-edge modifications focus on simple, deployable mechanisms comprised of extendable small flap panels over portions of the span that could be used to subtly but positively optimize the lift and drag characteristics. The report includes results from low speed wind tunnel testing of the trailing-edge devices, descriptions of potential mechanisms for automation, and an assessment of the technology.

  18. Electrodynamic Dust Shield for Surface Exploration Activities on the Moon and Mars

    NASA Technical Reports Server (NTRS)

    Calle, C. I.; Immer, C. D.; Clements, J. S.; Chen, A.; Buhler, C. R.; Lundeen, P.; Mantovani, J. G.; Starnes, J. W.; Michalenko, M.; Mazumder, M. K.

    2006-01-01

    The Apollo missions to the moon showed that lunar dust can hamper astronaut surface activities due to its ability to cling to most surfaces. NASA's Mars exploration landers and rovers have also shown that the problem is equally hard if not harder on Mars. In this paper, we report on our efforts to develop and electrodynamic dust shield to prevent the accumulation of dust on surfaces and to remove dust already adhering to those surfaces. The parent technology for the electrodynamic dust shield, developed in the 1970s, has been shown to lift and transport charged and uncharged particles using electrostatic and dielectrophoretic forces. This technology has never been applied for space applications on Mars or the moon due to electrostatic breakdown concerns. In this paper, we show that an appropriate design can prevent the electrostatic breakdown at the low Martian atmospheric pressures. We are also able to show that uncharged dust can be lifted and removed from surfaces under simulated Martian environmental conditions. This technology has many potential benefits for removing dust from visors, viewports and many other surfaces as well as from solar arrays. We have also been able to develop a version of the electrodynamic dust shield working under. hard vacuum conditions. This version should work well on the moon.

  19. The role of the atmospheric electric field in the dust-lifting process

    NASA Astrophysics Data System (ADS)

    Esposito, F.; Molinaro, R.; Popa, C. I.; Molfese, C.; Cozzolino, F.; Marty, L.; Taj-Eddine, K.; Di Achille, G.; Franzese, G.; Silvestro, S.; Ori, G. G.

    2016-05-01

    Mineral dust particles represent the most abundant component of atmospheric aerosol in terms of dry mass. They play a key role in climate and climate change, so the study of their emission processes is of utmost importance. Measurements of dust emission into the atmosphere are scarce, so that the dust load is generally estimated using models. It is known that the emission process can generate strong atmospheric electric fields. Starting from the data we acquired in the Sahara desert, here, we show for the first time that depending on the relative humidity conditions, electric fields contribute to increase up to a factor of 10 the amount of particles emitted into the atmosphere. This means that electrical forces and humidity are critical quantities in the dust emission process and should be taken into account in climate and circulation models to obtain more realistic estimations of the dust load in the atmosphere.

  20. Physiological and biomechanical responses to a prolonged repetitive asymmetric lifting activity.

    PubMed

    Mehta, Jay P; Lavender, Steven A; Jagacinski, Richard J

    2014-01-01

    This study investigated the effects of a prolonged repetitive asymmetric lifting task on behavioural adaptations during repetitive lifting activity, measures of tissue oxygenation and spine kinematics. Seventeen volunteers repeatedly lifted a box, normalised to 15% of the participant's maximum lifting strength, at the rate of 10 lifts/min for a period of 60 min. The lifts originated in front of the participants at ankle level and terminated on their left side at waist level. Overall, perceived workload increased during the repetitive lifting task. Erector spinae oxygenation levels, assessed using near-infrared spectroscopy, decreased significantly over time. Behavioural changes observed during the repetitive lifting task included increases in the amount of forward bending, the extension velocity and the lateral bending velocity, and a reduced lateral bending moment on the spine. These changes, with the exception of the reduced lateral bending moment, are associated with increased risk of low back disorder.

  1. Dust activity of Comet Halley's nucleus

    NASA Technical Reports Server (NTRS)

    Keller, H. U.; Delamere, W. A.; Huebner, W. F.; Reitsema, H.; Schmidt, H. U.; Schmidt, W. K. H.; Whipple, Fred L.; Wilhelm, K.

    1986-01-01

    Images obtained by the Halley multicolor camera using the clear filter with a pass band from 300 to 1000 nm were used to study dust activity in the comet nucleus. Comparisons with ground based observations confirm that dust production towards the Sun increases in activity relative to the southern background source while the Giotto spacecraft was approaching. This is in agreement with the assumption that the sunward activity becomes stronger when the source rotates towards the Sun. Estimated dust column density is 90 billion/sqm, with optical thickness less than or = 0.3. Surface reflectivity is less than 1%, indicating a very rough surface with large fractions of shadowed areas.

  2. Regime shift in Arabian dust activity, triggered by persistent Fertile Crescent drought

    NASA Astrophysics Data System (ADS)

    Notaro, Michael; Yu, Yan; Kalashnikova, Olga V.

    2015-10-01

    The Arabian Peninsula has experienced pronounced interannual to decadal variability in dust activity, including an abrupt regime shift around 2006 from an inactive dust period during 1998-2005 to an active period during 2007-2013. Corresponding in time to the onset of this regime shift, the climate state transitioned into a combined La Niña and negative phase of the Pacific Decadal Oscillation, which incited a hiatus in global warming in the 2000s. Superimposed upon a long-term regional drying trend, synergistic interactions between these teleconnection modes triggered the establishment of a devastating and prolonged drought, which engulfed the Fertile Crescent, namely, Iraq and Syria, and led to crop failure and civil unrest. Dried soils and diminished vegetation cover in the Fertile Crescent, as evident through remotely sensed enhanced vegetation indices, supported greater dust generation and transport to the Arabian Peninsula in 2007-2013, as identified both in increased dust days observed at weather stations and enhanced remotely sensed aerosol optical depth. According to backward trajectory analysis of dust days on the Arabian Peninsula, increased dust lifting and atmospheric dust concentration in the Fertile Crescent during this recent, prolonged drought episode supported a greater frequency of dust events across the peninsula with associated northerly trajectories and led to the dust regime shift. These findings are particularly concerning, considering projections of warming and drying for the eastern Mediterranean region and potential collapse of the Fertile Crescent during this century.

  3. Active Dust Control and Mitigation Technology for Lunar and Martian Exploration

    NASA Technical Reports Server (NTRS)

    Calle, C. I.; Buhler, C. R.; Johansen, M. R.; Hogue, M. D.; Immer, C. D.; Ferreira, J.; Snyder, S. J.

    2010-01-01

    Mars is covered with a layer of dust that has been homogenized by global dust storms. Dust, levitated by these storms as well as by the frequent dust devils, is the dominant weather phenomenon on Mars. NASA's Mars exploration rovers have shown that atmospheric dust falling on solar panels can decrease their efficiency to the point of rendering the rover unusable. Dust covering the surface of the moon is expected to be electrostatically charged due to the solar wind, cosmic rays, and the solar radiation itself through the photoelectric effect. Electrostatically charged dust has a large tendency to adhere to surfaces. The Apollo missions to the moon showed that lunar dust adhesion can hinder manned and unmanned exploration activities. In this paper, we report on our efforts to develop and electrodynamic dust shield to prevent the accumulation of dust on surfaces and to remove dust already adhering to those surfaces. The technology uses electrostatic and dielectrophoretic forces to carry dust particles off surfaces and to generate an electrodynamic shield that prevents further accumulation of dust. The concept of the electrodynamic dust shield was introduced by NASA in the late 1960s and later reduced to practice during the 1970s for terrestrial applications. In 2003, our laboratory, in collaboration with several universities, applied this technology to space applications, specifically to remove dust from solar panels on Mars. We show how, with an appropriate design, we can prevent the electrostatic breakdown at the low Martian atmospheric pressures. We are also able to show that uncharged dust can be lifted and removed from surfaces under simulated Martian environmental conditions. We have also been able to develop a version of the electrodynamic dust shield working under hard vacuum conditions that simulate the lunar environment. We have implemented the electrodynamic dust shield on solar arrays, optical systems, spectrometers, viewports, thermal radiators

  4. Active Flow Control of Lifting Surface With Flap-Current Activities and Future Directions

    NASA Technical Reports Server (NTRS)

    Ahmadi, G.; Marzocca, P.; Jha, R.; Alstorm, B.; Obied, S.; Kabir, P.; Shahrabi, A.

    2010-01-01

    The main objective is to develop effective control strategies for separation control of an airfoil with a single hinge flap. The specific objectives are: Develop an active control architecture for flow control around an airfoil with flap. Design, fabricate, a wind tunnel test of a high lift wing (with flap) with integrated actuators and sensors. Design, development and fabrication of synthetic jet actuators. Develop appropriate control strategy for application to the airfoil. Wind tunnel testing of the high lift wing at various angles of attack and flap positions with closed loop control.

  5. Silica dust exposures during selected construction activities.

    PubMed

    Flanagan, Mary Ellen; Seixas, Noah; Majar, Maria; Camp, Janice; Morgan, Michael

    2003-01-01

    This study characterized exposure for dust-producing construction tasks. Eight common construction tasks were evaluated for quartz and respirable dust exposure by collecting 113 personal task period samples for cleanup; demolition with handheld tools; concrete cutting; concrete mixing; tuck-point grinding; surface grinding; sacking and patching concrete; and concrete floor sanding using both time-integrating filter samples and direct-reading respirable dust monitors. The geometric mean quartz concentration was 0.10 mg/m(3) (geometric standard deviation [GSD]=4.88) for all run time samples, with 71% exceeding the threshold limit value. Activities with the highest exposures were surface grinding, tuck-point grinding, and concrete demolition (GM[GSD] of 0.63[4.12], 0.22[1.94], and 0.10[2.60], respectively). Factors recorded each minute were task, tool, work area, respiratory protection and controls used, estimated cross draft, and whether anyone nearby was making dust. Factors important to exposure included tool used, work area configuration, controls employed, cross draft, and in some cases nearby dust. More protective respirators were employed as quartz concentration increased, although respiratory protection was found to be inadequate for 42% of exposures. Controls were employed for only 12% of samples. Exposures were reduced with three controls: box fan for surface grinding and floor sanding, and vacuum/shroud for surface grinding, with reductions of 57, 50, and 71%, respectively. Exposures were higher for sweeping compound, box fan for cleanup, ducted fan dilution, and wetted substrate. Construction masons and laborers are frequently overexposed to silica. The usual protection method, respirators, was not always adequate, and engineering control use was infrequent and often ineffective.

  6. Development of high-lift laminar wing using steady active flow control

    NASA Astrophysics Data System (ADS)

    Clayton, Patrick J.

    Fuel costs represent a large fraction of aircraft operating costs. Increased aircraft fuel efficiency is thus desirable. Laminar airfoils have the advantage of reduced cruise drag and increased fuel efficiency. Unfortunately, they cannot perform adequately during high-lift situations (i.e. takeoff and landing) due to low stall angles and low maximum lift caused by flow separation. Active flow control has shown the ability to prevent or mitigate separation effects, and increase maximum lift. This fact makes AFC technology a fitting solution for improving high-lift systems and reducing the need for slats and flap elements. This study focused on experimentally investigating the effects of steady active flow control from three slots, located at 1%, 10%, and 80% chord, respectively, over a laminar airfoil with 45 degree deflected flap. A 30-inch-span airfoil model was designed, fabricated, and then tested in the Bill James 2.5'x3' Wind Tunnel at Iowa State University. Pressure data were collected along the mid-span of the airfoil, and lift and drag were calculated. Five test cases with varying injection locations and varying Cμ were chosen: baseline, blown flap, leading edge blowing, equal blowing, and unequal blowing. Of these cases, unequal blowing achieved the greatest lift enhancement over the baseline. All cases were able to increase lift; however, gains were less than anticipated.

  7. DUST EMISSION FROM UNOBSCURED ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Thompson, G. D.; Levenson, N. A.; Uddin, S. A.; Sirocky, M. M.

    2009-05-20

    We use mid-infrared (MIR) spectroscopy of unobscured active galactic nuclei (AGNs) to reveal their native dusty environments. We concentrate on Seyfert 1 galaxies, observing a sample of 31 with the Infrared Spectrograph aboard the Spitzer Space Telescope, and compare them with 21 higher luminosity quasar counterparts. Silicate dust reprocessing dominates the MIR spectra, and we generally measure the 10 and 18 {mu}m spectral features weakly in emission in these galaxies. The strengths of the two silicate features together are sensitive to the dust distribution. We present numerical radiative transfer calculations that distinguish between clumpy and smooth geometries, which are applicable to any central heating source, including stars as well as AGNs. In the observations, we detect the obscuring 'torus' of unified AGN schemes, modeling it as compact and clumpy. We also determine that star formation increases with AGN luminosity, although the proportion of the galaxies' bolometric luminosity attributable to stars decreases with AGN luminosity.

  8. Dust Emission from Unobscured Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Thompson, G. D.; Levenson, N. A.; Uddin, S. A.; Sirocky, M. M.

    2009-05-01

    We use mid-infrared (MIR) spectroscopy of unobscured active galactic nuclei (AGNs) to reveal their native dusty environments. We concentrate on Seyfert 1 galaxies, observing a sample of 31 with the Infrared Spectrograph aboard the Spitzer Space Telescope, and compare them with 21 higher luminosity quasar counterparts. Silicate dust reprocessing dominates the MIR spectra, and we generally measure the 10 and 18 μm spectral features weakly in emission in these galaxies. The strengths of the two silicate features together are sensitive to the dust distribution. We present numerical radiative transfer calculations that distinguish between clumpy and smooth geometries, which are applicable to any central heating source, including stars as well as AGNs. In the observations, we detect the obscuring "torus" of unified AGN schemes, modeling it as compact and clumpy. We also determine that star formation increases with AGN luminosity, although the proportion of the galaxies' bolometric luminosity attributable to stars decreases with AGN luminosity.

  9. Electrical Activity in Martian Dust Storms

    NASA Astrophysics Data System (ADS)

    Majid, W.

    2015-12-01

    Dust storms on Mars are predicted to be capable of producing electrostatic fields and discharges, even larger than those in dust storms on Earth. Such electrical activity poses serious risks to any Human exploration of the planet and the lack of sufficient data to characterize any such activity has been identified by NASA's MEPAG as a key human safety knowledge gap. There are three key elements in the characterization of Martian electrostatic discharges: dependence on Martian environmental conditions, frequency of occurrence, and the strength of the generated electric fields. We will describe a proposed program using NASA's Deep Space Network (DSN) to carry out a long term monitoring campaign to search for and characterize the entire Mars hemisphere for powerful discharges during routine tracking of spacecraft at Mars on an entirely non-interfering basis. The resulting knowledge of Mars electrical activity would allow NASA to plan risk mitigation measures to ensure human safety during Mars exploration. In addition, these measurements will also allow us to place limits on presence of oxidants such as H2O2 that may be produced by such discharges, providing another measurement point for models describing Martian atmospheric chemistry and habitability. Because of the continuous Mars telecommunication needs of NASA's Mars-based assets, the DSN is the only instrument in the world that combines long term, high cadence, observing opportunities with large sensitive telescopes, making it a unique asset worldwide in searching for and characterizing electrostatic activity at Mars from the ground.

  10. Local dynamic stability of spine muscle activation and stiffness patterns during repetitive lifting.

    PubMed

    Graham, Ryan B; Brown, Stephen H M

    2014-12-01

    To facilitate stable trunk kinematics, humans must generate appropriate motor patterns to effectively control muscle force and stiffness and respond to biomechanical perturbations and/or neuromuscular control errors. Thus, it is important to understand physiological variables such as muscle force and stiffness, and how these relate to the downstream production of stable spine and trunk movements. This study was designed to assess the local dynamic stability of spine muscle activation and rotational stiffness patterns using Lyapunov analyses, and relationships to the local dynamic stability of resulting spine kinematics, during repetitive lifting and lowering at varying combinations of lifting load and rate. With an increase in the load lifted at a constant rate there was a trend for decreased local dynamic stability of spine muscle activations and the muscular contributions to spine rotational stiffness; although the only significant change was for the full state space muscle activation stability (p < 0.05). With an increase in lifting rate with a constant load there was a significant decrease in the local dynamic stability of spine muscle activations and the muscular contributions to spine rotational stiffness (p ≤ 0.001 for all measures). These novel findings suggest that the stability of motor inputs and the muscular contributions to spine rotational stiffness can be altered by external task demands (load and lifting rate), and therefore are important variables to consider when assessing the stability of the resulting kinematics.

  11. The formation and dust lifting processes associated with a large Saharan meso-scale convective system (MCS)

    NASA Astrophysics Data System (ADS)

    Roberts, Alex; Knippertz, Peter

    2013-04-01

    This work focusses on the meteorology that produced a large Mesoscale Convective System (MCS) and the dynamics of its associated cold pool. The case occurred between 8th-10th June 2010 and was initiated over the Hoggar and Aïr Mountains in southern Algeria and northern Niger respectively. The dust plume created covered parts of Algeria, Mali and Mauritania and was later deformed the by background flow and transported over the Atlantic and Mediterranean. This study is based on: standard surface observations (where available), ERA-Interim reanalysis, Meteosat imagery, MODIS imagery, Tropical Rainfall Measuring Mission (TRMM) rainfall estimates, Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), CloudSat and a high resolution (3.3km) limited area simulation using the Weather Research and Forecasting (WRF) model. A variety of different processes appear to be important for the generation of this MCS and the spreading of the associated dusty cold pool. These include: the presence of a trough on the subtropical jet, the production of a tropical cloud plume, disruption to the structure of the Saharan heat low and the production of a Libyan high. These features produced moistening of the boundary layer and a convergence zone over the region of MCS initiation. Another important factor appears to have been the production of a smaller MCS and cold pool on the evening of the 7th June. This elevated low-level moisture and encouraged convective initiation the following day. Once triggered on the 8th June some cells grew and merged into a single large system that propagated south westward and produced a large cold pool that emanated from its northern edge. The cells on the northern edge of the system over the Hoggar grew and collapsed producing a haboob that spread over a large area. Cells further south continued to develop into the MCS and actively produce a cold pool over the system's lifetime. This undercut the dusty air from the earlier cold pool and

  12. Evaluation of dust activity and climate effects in North China.

    PubMed

    Xia, Xiang-ao; Liang, Feng; Wang, Ming-xing

    2004-01-01

    TOMS/AI data with nearly 20 years are utilized in the paper to evaluate dust activities in North China. Combined with simultaneous NCEP reanalysis climate data, climate effects on dust activities are assessed. The results showed that the whole North China suffers impact by dust aerosols, with three centers standing out in TOMS/AI spring average map that are western three basins, which are characterized by lower annual precipitation and elevation. Gobi deserts in Mongolia Plateau do not attain higher TOMS/AI value due to cloud contamination and relative higher elevation. Spring is the season with the highest TOMS dust aerosol index; within the western three basins, high dust aerosol index appears in both spring and summer, especially in Tarim Basin. Wind speed in spring and precipitation in previous rainy season play important roles in controlling dust activities, higher wind speed and less precipitation than the normal are in favor of dust activities in spring. Temperature in spring and previous winter also affect dust activity to a certain extent, but with contrary spatial distribution. Temperature in winter exert effect principally in west part, contrarily, temperature effect in spring is mainly shown in east part. Both of them have negative correlation with dust activity.

  13. Active Dust Experiment in the Mesosphere

    SciTech Connect

    Norberg, Carol; Pellinen-Wannberg, Asta

    2008-09-07

    The mesosphere stretches from an altitude of about 50 to 90 km above the Earth's surface. Meteors entering the Earth's atmosphere are believed to ablate and hence give rise to a thin layer of dust particles in the upper part of the Earth's mesosphere. It seems that the dust is most dense in a layer that lies between 80 and 90 km. The dust particles are thought to have sizes of a few to tens of nanometers. Efforts have been made to measure these particles using rockets and radar techniques with limited success. We propose to release dust into the mesosphere over northern Sweden at a height of about 90 km and observe the released dust using the EISCAT radar system. The dust will be launched from the Swedish Space Corporation Esrange Space Centre on a single-stage Improved-Orion rocket that will be launched so that its flight path will be in the radar field of view.

  14. Cholinesterase activity in Japanese quail dusted with carbaryl

    USGS Publications Warehouse

    Hill, E.F.

    1979-01-01

    Japanese quail (Coturnix coturnix japonica) were dusted with 5% carbaryl to determine if this topical treatment would alter plasma and brain cholinesterase activities. Within 6 hours after dusting, plasma cholinesterase activity was depressed compared with controls, the depression averaging 20% for females and 27% for males. By 24 hours the cholinesterase activity of females had returned to normal, but the cholinesterase activity of males remained depressed. Brain cholinesterase activity was not affected by the treatment, and there were no overt toxic signs.

  15. New method of neck surface electromyography for the evaluation of tongue-lifting activity.

    PubMed

    Manda, Y; Maeda, N; Pan, Q; Sugimoto, K; Hashimoto, Y; Tanaka, Y; Kodama, N; Minagi, S

    2016-06-01

    Elevation of the posterior part of the tongue is important for normal deglutition and speech. The purpose of this study was to develop a new surface electromyography (EMG) method to non-invasively and objectively evaluate activity in the muscles that control lifting movement in the posterior tongue. Neck surface EMG (N-EMG) was recorded using differential surface electrodes placed on the neck, 1 cm posterior to the posterior border of the mylohyoid muscle on a line orthogonal to the lower border of the mandible. Experiment 1: Three healthy volunteers (three men, mean age 37·7 years) participated in an evaluation of detection method of the posterior tongue lifting up movement. EMG recordings from the masseter, temporalis and submental muscles and N-EMG revealed that i) N-EMG was not affected by masseter muscle EMG and ii) N-EMG activity was not observed during simple jaw opening and tongue protrusion, revealing the functional difference between submental surface EMG and N-EMG. Experiment 2: Seven healthy volunteers (six men and one woman, mean age 27·9 years) participated in a quantitative evaluation of muscle activity. Tongue-lifting tasks were perfor-med, exerting a prescribed force of 20, 50, 100 and 150 gf with visual feedback. For all subjects, a significant linear relationship was observed bet-ween the tongue-lifting force and N-EMG activity (P < 0·01). These findings indicate that N-EMG can be used to quantify the force of posterior tongue lifting and could be useful to evaluate the effect of tongue rehabilitation in future studies.

  16. Mars Orbiter Camera climatology of textured dust storms

    NASA Astrophysics Data System (ADS)

    Guzewich, Scott D.; Toigo, Anthony D.; Kulowski, Laura; Wang, Huiqun

    2015-09-01

    We report the climatology of "textured dust storms", those dust storms that have visible structure on their cloud tops that are indicative of active dust lifting, as observed in Mars Daily Global Maps produced from Mars Orbiter Camera wide-angle images. Textured dust storms predominantly occur in the equinox seasons while both solstice periods experience a planet-wide "pause" in textured dust storm activity. These pauses correspond to concurrent decreases in global atmospheric dust opacity. Textured dust storms most frequently occur in Acidalia Planitia, Chryse Planitia, Arcadia Planitia, and Hellas basin. To examine the nature of the link between textured dust storms and atmospheric dust opacity, we compare the textured dust storm climatology with a record of atmospheric dust opacity and find a peak global correlation coefficient of approximately 0.5 with a lag of 20-40° in solar longitude in the opacity compared to the solar climatology. This implies that textured dust storms observed at 1400 local time by MOC are responsible for a large fraction of atmospheric dust opacity and that other mechanisms (e.g., dust devil lifting or storm-scale lifting not observed in this study) may supply a comparable amount of dust.

  17. Increasing Arabian dust activity and the Indian summer monsoon

    NASA Astrophysics Data System (ADS)

    Solmon, F.; Nair, V. S.; Mallet, M.

    2015-07-01

    Over the past decade, aerosol optical depth (AOD) observations based on satellite and ground measurements have shown a significant increase over Arabia and the Arabian Sea, attributed to an intensification of regional dust activity. Recent studies have also suggested that west Asian dust forcing could induce a positive response of Indian monsoon precipitations on a weekly timescale. Using observations and a regional climate model including interactive slab-ocean and dust aerosol schemes, the present study investigates possible climatic links between the increasing June-July-August-September (JJAS) Arabian dust activity and precipitation trends over southern India during the 2000-2009 decade. Meteorological reanalysis and AOD observations suggest that the observed decadal increase of dust activity and a simultaneous intensification of summer precipitation trend over southern India are both linked to a deepening of JJAS surface pressure conditions over the Arabian Sea. In the first part of the study, we analyze the mean climate response to dust radiative forcing over the domain, discussing notably the relative role of Arabian vs. Indo-Pakistani dust regions. In the second part of the study, we show that the model skills in reproducing regional dynamical patterns and southern Indian precipitation trends are significantly improved only when an increasing dust emission trend is imposed on the basis of observations. We conclude that although interannual climate variability might primarily determine the observed regional pattern of increasing dust activity and precipitation during the 2000-2009 decade, the associated dust radiative forcing might in return induce a critical dynamical feedback contributing to enhancing regional moisture convergence and JJAS precipitations over southern India.

  18. Monitoring atmospheric dust spring activity at high southern latitudes on Mars using OMEGA

    NASA Astrophysics Data System (ADS)

    Douté, S.

    2014-06-01

    This paper presents a monitoring of the atmospheric dust in the south polar region during spring of Martian year 27. Our goal is to contribute to identifying the regions where the dust concentration in the atmosphere shows specific temporal patterns, for instance high, variable, and on the rise due to lifting or transport mechanisms. This identification is performed in relation with the seasonal ice regression. Based on a phenomenological examination of the previous results, hypothesis regarding the origin of aerosol activity of the southern polar region is proposed. This is of paramount importance since local dust storms generated in this region sometimes grow to global proportions. The imaging spectrometer OMEGA on board Mars Express has acquired the most comprehensive set of observations to date in the near-infrared (0.93-5.1 μm) of the southern high latitudes of Mars from mid-winter solstice (Ls=110°, December 2004) to the end of the recession at Ls=320° (November 2005). We use two complementary methods in order to retrieve the optical depth of the atmospheric dust at a reference wavelength of 1 μm. The methods are independently operated for pixels showing mineral surfaces on the one hand and the seasonal cap on the other hand. They are applied on a time series of OMEGA images acquired between LS=220° and LS=280° . As a result the aerosol optical depth (AOD) is mapped and binned at a spatial resolution of 1.0° pixel-1 and with a mean period of AOD sampling ranging from less than two sols for latitudes higher than 80°S to approximately six sols at latitudes in the interval 65-75°S. We then generate and interpret time series of orthographic mosaics depicting the spatio-temporal distribution of the seasonal mean values, the variance and the local time dependence of the AOD. In particular we suspect that two mechanisms play a major role for lifting and transporting efficiently mineral particles and create dust events or storms: (i) nighttime katabatic

  19. Discoveries from Revisiting Apollo Direct Active Measurements of Lunar Dust

    NASA Astrophysics Data System (ADS)

    O'Brien, Brian

    2010-05-01

    New missions to the moon being developed by China, Japan, India, USA, Russia and Europe and possibilities of human missions about 2020 face the reality that 6 Apollo expeditions did not totally manage or mitigate effects of easily-mobilised and very "sticky" lunar dust on humans and hardware. Laboratory and theoretical modelling cannot reliably simulate the complex lunar environments that affect dynamical movements of lunar dust. The only direct active measurements of lunar dust during Apollo were made by matchbox-sized minimalist Dust Detector Experiments (DDEs) deployed to transmit some 30 million digital measurements from Apollo 11, 12, 14 and 15. These were misplaced or relatively ignored until 2009, when a self-funded suite of discoveries (O'Brien Geophys. Research Letters FIX 6 May 2099) revealed unexpected properties of lunar dust, such as the adhesive force being stronger as illumination increased. We give the first reports of contrasting effects, contamination or cleansing, from rocket exhausts of Apollo 11, 12, 14 and 15 Lunar Modules leaving the moon. We further strengthen the importance of collateral dust inadvertently splashed on Apollo hardware by human activities. Dust management designs and mission plans require optimum use of such in situ measurements, extended by laboratory simulations and theoretical modelling.

  20. Lunar Dust Characterization Activity at GRC

    NASA Technical Reports Server (NTRS)

    Street, Kenneth W.

    2008-01-01

    The fidelity of lunar simulants as compared to actual regolith is evaluated using Figures of Merit (FOM) which are based on four criteria: Particle Size, Particle Shape, Composition, and Density of the bulk material. In practice, equipment testing will require other information about both the physical properties (mainly of the dust fraction) and composition as a function of particle size. At Glenn Research Center (GRC) we are involved in evaluating a number of simulant properties of consequence to testing of lunar equipment in a relevant environment, in order to meet Technology Readiness Level (TRL) 6 criteria. Bulk regolith has been characterized for many decades, but surprisingly little work has been done on the dust fraction (particles less than 20 micrometers in diameter). GRC is currently addressing the information shortfall by characterizing the following physical properties: Particle Size Distribution, Adhesion, Abrasivity, Surface Energy, Magnetic Susceptibility, Tribocharging and Surface Chemistry/Reactivity. Since some of these properties are also dependent on the size of the particles we have undertaken the construction of a six stage axial cyclone particle separator to fractionate dust into discrete particle size distributions for subsequent evaluation of these properties. An introduction to this work and progress to date will be presented.

  1. LIFTING THE VEIL OF DUST FROM NGC 0959: THE IMPORTANCE OF A PIXEL-BASED TWO-DIMENSIONAL EXTINCTION CORRECTION

    SciTech Connect

    Tamura, K.; Jansen, R. A.; Windhorst, R. A.; Eskridge, P. B.; Cohen, S. H.

    2010-06-15

    We present the results of a study of the late-type spiral galaxy NGC 0959, before and after application of the pixel-based dust extinction correction described in Tamura et al. (Paper I). Galaxy Evolution Explorer far-UV, and near-UV, ground-based Vatican Advanced Technology Telescope, UBVR, and Spitzer/Infrared Array Camera 3.6, 4.5, 5.8, and 8.0 {mu}m images are studied through pixel color-magnitude diagrams and pixel color-color diagrams (pCCDs). We define groups of pixels based on their distribution in a pCCD of (B - 3.6 {mu}m) versus (FUV - U) colors after extinction correction. In the same pCCD, we trace their locations before the extinction correction was applied. This shows that selecting pixel groups is not meaningful when using colors uncorrected for dust. We also trace the distribution of the pixel groups on a pixel coordinate map of the galaxy. We find that the pixel-based (two-dimensional) extinction correction is crucial for revealing the spatial variations in the dominant stellar population, averaged over each resolution element. Different types and mixtures of stellar populations, and galaxy structures such as a previously unrecognized bar, become readily discernible in the extinction-corrected pCCD and as coherent spatial structures in the pixel coordinate map.

  2. Ice Nucleation Activity of Various Agricultural Soil Dust Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Schiebel, Thea; Höhler, Kristina; Funk, Roger; Hill, Thomas C. J.; Levin, Ezra J. T.; Nadolny, Jens; Steinke, Isabelle; Suski, Kaitlyn J.; Ullrich, Romy; Wagner, Robert; Weber, Ines; DeMott, Paul J.; Möhler, Ottmar

    2016-04-01

    Recent investigations at the cloud simulation chamber AIDA (Aerosol Interactions and Dynamics in the Atmosphere) suggest that agricultural soil dust has an ice nucleation ability that is enhanced up to a factor of 10 compared to desert dust, especially at temperatures above -26 °C (Steinke et al., in preparation for submission). This enhancement might be caused by the contribution of very ice-active biological particles. In addition, soil dust aerosol particles often contain a considerably higher amount of organic matter compared to desert dust particles. To test agricultural soil dust as a source of ice nucleating particles, especially for ice formation in warm clouds, we conducted a series of laboratory measurements with different soil dust samples to extend the existing AIDA dataset. The AIDA has a volume of 84 m3 and operates under atmospherically relevant conditions over wide ranges of temperature, pressure and humidity. By controlled adiabatic expansions, the ascent of an air parcel in the troposphere can be simulated. As a supplement to the AIDA facility, we use the INKA (Ice Nucleation Instrument of the KArlsruhe Institute of Technology) continuous flow diffusion chamber based on the design by Rogers (1988) to expose the sampled aerosol particles to a continuously increasing saturation ratio by keeping the aerosol temperature constant. For our experiments, soil dust was dry dispersed into the AIDA vessel. First, fast saturation ratio scans at different temperatures were performed with INKA, sampling soil dust aerosol particles directly from the AIDA vessel. Then, we conducted the AIDA expansion experiment starting at a preset temperature. The combination of these two different methods provides a robust data set on the temperature-dependent ice activity of various agriculture soil dust aerosol particles with a special focus on relatively high temperatures. In addition, to extend the data set, we investigated the role of biological and organic matter in more

  3. Active Control of Flow Separation on a High-Lift System with Slotted Flap at High Reynolds Number

    NASA Technical Reports Server (NTRS)

    Khodadoust, Abdollah; Washburn, Anthony

    2007-01-01

    The NASA Energy Efficient Transport (EET) airfoil was tested at NASA Langley's Low- Turbulence Pressure Tunnel (LTPT) to assess the effectiveness of distributed Active Flow Control (AFC) concepts on a high-lift system at flight scale Reynolds numbers for a medium-sized transport. The test results indicate presence of strong Reynolds number effects on the high-lift system with the AFC operational, implying the importance of flight-scale testing for implementation of such systems during design of future flight vehicles with AFC. This paper describes the wind tunnel test results obtained at the LTPT for the EET high-lift system for various AFC concepts examined on this airfoil.

  4. An analysis of the history of dust activity on Mars

    NASA Astrophysics Data System (ADS)

    Martin, L. J.; Zurek, R. W.

    1993-02-01

    A comprehensive list of dust storm activity on Mars has been compiled from various published lists and additional data. For uniformity and clarity, each event is classified using a new system that includes a well-defined nomenclature. Maps showing the reported locations of events have been compiled. Detailed commentaries describe the events and/or circumstances of their observation. The seasonal distribution of Martian dust events is diagrammed and discussed together with a seasonal and annual (Mars years) timeline that includes the frequency of photographic coverage. Regional dust storms tend to occur most frequently, and all planet-encircling dust storms have been observed during the southern spring and summer seasons, although there is significant interannual variability.

  5. Drag and lift reduction of a 3D bluff-body using active vortex generators

    NASA Astrophysics Data System (ADS)

    Aider, Jean-Luc; Beaudoin, Jean-François; Wesfreid, José Eduardo

    2010-05-01

    In this study, a passive flow control experiment on a 3D bluff-body using vortex generators (VGs) is presented. The bluff-body is a modified Ahmed body (Ahmed in J Fluids Eng 105:429-434 1983) with a curved rear part, instead of a slanted one, so that the location of the flow separation is no longer forced by the geometry. The influence of a line of non-conventional trapezoïdal VGs on the aerodynamic forces (drag and lift) induced on the bluff-body is investigated. The high sensitivity to many geometric (angle between the trapezoïdal element and the wall, spanwise spacing between the VGs, longitudinal location on the curved surface) and physical (freestream velocity) parameters is clearly demonstrated. The maximum drag reduction is -12%, while the maximum global lift reduction can reach more than -60%, with a strong dependency on the freestream velocity. For some configurations, the lift on the rear axle of the model can be inverted (-104%). It is also shown that the VGs are still efficient even downstream of the natural separation line. Finally, a dynamic parameter is chosen and a new set-up with motorized vortex generators is proposed. Thanks to this active device. The optimal configurations depending on two parameters are found more easily, and a significant drag and lift reduction (up to -14% drag reduction) can be reached for different freestream velocities. These results are then analyzed through wall pressure and velocity measurements in the near-wake of the bluff-body with and without control. It appears that the largest drag and lift reduction is clearly associated to a strong increase of the size of the recirculation bubble over the rear slant. Investigation of the velocity field in a cross-section downstream the model reveals that, in the same time, the intensity of the longitudinal trailing vortices is strongly reduced, suggesting that the drag reduction is due to the breakdown of the balance between the separation bubble and the longitudinal vortices

  6. Saharan Dust, Transport Processes, and Possible Impacts on Hurricane Activities

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Kim, K. M.

    2010-01-01

    In this paper, we present observational evidence of significant relationships between Saharan dust outbreak, and African Easterly wave activities and hurricane activities. We found two dominant paths of transport of Saharan dust: a northern path, centered at 25degN associated with eastward propagating 6-19 days waves over northern Africa, and a southern path centered at 15degN, associated with the AEW, and the Atlantic ITCZ. Seasons with stronger dust outbreak from the southern path are associated with a drier atmosphere over the Maximum Development Region (MDR) and reduction in tropical cyclone and hurricane activities in the MDR. Seasons with stronger outbreak from the northern path are associated with a cooler N. Atlantic, and suppressed hurricane in the western Atlantic basin.

  7. Interlaboratory comparison on 137Cs activity concentration in fume dust

    NASA Astrophysics Data System (ADS)

    Tzika, Faidra; Hult, Mikael; Burda, Oleksiy; Arnold, Dirk; Sibbens, Goedele; Caro Marroyo, Belén; Gómez-Mancebo, Maria Belén; Peyrés, Virginia; Moser, Hannah; Ferreux, Laurent; Šolc, Jaroslav; Dryák, Pavel; Fazio, Aldo; Luca, Aurelian; Vodenik, Branko; Reis, Mario; Tyminski, Zbigniew; Klemola, Seppo

    2015-11-01

    A comparison was conducted, between 11 European National Metrology Institutes and EC-JRC, on measurement of 137Cs activity concentration in fume dust. As test material an activity standard produced from real contaminated fume dust was used. The standard material consisted of 13 cylindrical samples of compressed fume dust. The material contained 137Cs and 60Co of reference activity concentrations of (9.72±0.10) Bq/g and (0.450±0.018) Bq/g, respectively, for the reference date of 1 June 2013, determined using the comparison results. The organization and results of the intercomparison, as well as the process of obtaining reliable reference values are presented.

  8. Dust Eruptions on Mars by Temperature Gradient Induced Forces

    NASA Astrophysics Data System (ADS)

    Kelling, Thorben; Wurm, G.; Reiss, D.; Kocifaj, M.; Klacka, J.; Teiser, J.

    2009-09-01

    Dust lifting processes on Mars are an active field of investigation. Explanations for dust phenomena even on high elevations on Mars have to be found. In general, wind stress is supposed to be the main lifting process but on average wind velocities are too low. We found, that temperature induced forces are capable of procuring dust ejections and even massive dust eruptions from a dust bed. A Mars soil simulant (JSC Mars 1A) was placed within a vacuum chamber which was evacuated to typical martian pressures of some mbar and particle ejections and eruptions were observed. Several different temperature gradient dependend lifting processes are at work. While e.g. photophoretic and thermophoretic forces only result in minor particle ejections, Knudsen Compressor effects cause continuous and major eruptions. These eruptions are even enhanced if a transition from illumination to no illumination occurs. We argue that the massive transition eruptions may be the dominant dust lifting process for e.g. dust devils. Moving dust devils, which are optically thick, induce a fast transition from light to shadow for the underlying dust bed. Even for lower initial radiation intensities, this will result in particle eruptions. As long as the wind eddy exists, dust devils on Mars may be self sustained even at low pressures or high altitudes. This work recieved support by the DFG and DAAD.

  9. Dust Loss from Activated Asteroid P/2015 X6

    NASA Astrophysics Data System (ADS)

    Moreno, F.; Licandro, J.; Cabrera-Lavers, A.; Pozuelos, F. J.

    2016-08-01

    We present observations and dust tail models of activated asteroid P/2015 X6 from deep imaging data acquired at the 10.4 m Gran Telescopio Canarias (GTC) from 2015 mid-December to 2016 late January. The results of the modeling indicate that the asteroid has undergone sustained dust loss over a period of two months or longer. The dust parameters, derived from multidimensional fits of the available images, are compatible with either ice sublimation or rotational instability processes. An impulsive event, as might be associated with an impact with another body, is less likely. A power-law distribution of particles, with minimum and maximum radii of 1 μm and 1 cm and a power index of -3.3, is found to be consistent with the observations. Depending on the model of ejection velocity adopted, the particle velocities are found to be in the range of 0.3-10 m s-1. The activation time was between 18 and 26 days before discovery. The total mass ejected from that time to the most recent observation is in the range 5-9 × 106 kg. No dust features giving indication of past activity earlier than the activation time have been observed.

  10. Dust Loss from Activated Asteroid P/2015 X6

    NASA Astrophysics Data System (ADS)

    Moreno, F.; Licandro, J.; Cabrera-Lavers, A.; Pozuelos, F. J.

    2016-08-01

    We present observations and dust tail models of activated asteroid P/2015 X6 from deep imaging data acquired at the 10.4 m Gran Telescopio Canarias (GTC) from 2015 mid-December to 2016 late January. The results of the modeling indicate that the asteroid has undergone sustained dust loss over a period of two months or longer. The dust parameters, derived from multidimensional fits of the available images, are compatible with either ice sublimation or rotational instability processes. An impulsive event, as might be associated with an impact with another body, is less likely. A power-law distribution of particles, with minimum and maximum radii of 1 μm and 1 cm and a power index of ‑3.3, is found to be consistent with the observations. Depending on the model of ejection velocity adopted, the particle velocities are found to be in the range of 0.3–10 m s‑1. The activation time was between 18 and 26 days before discovery. The total mass ejected from that time to the most recent observation is in the range 5–9 × 106 kg. No dust features giving indication of past activity earlier than the activation time have been observed.

  11. Jovian dust streams: A monitor of Io's volcanic plume activity

    USGS Publications Warehouse

    Kruger, H.; Geissler, P.; Horanyi, M.; Graps, A.L.; Kempf, S.; Srama, R.; Moragas-Klostermeyer, G.; Moissl, R.; Johnson, T.V.; Grun, E.

    2003-01-01

    Streams of high speed dust particles originate from Jupiter's moon Io. After release from Io, the particles collect electric charges in the Io plasma torus, gain energy from the co-rotating electric field of Jupiter's magnetosphere, and leave the Jovian system into interplanetary space with escape speeds over 200 km s-1. The Galileo spacecraft has continuously monitored the dust streams during 34 revolutions about Jupiter between 1996 and 2002. The observed dust fluxes exhibit large orbit-to-orbit variability due to systematic and stochastic changes. After removal of the systematic variations, the total dust emission rate of Io has been calculated. It varies between 10-3 and 10 kg s-1, and is typically in the range of 0.1 to 1 kg s-1. We compare the dust emission rate with other markers of volcanic activity on Io like large-area surface changes caused by volcanic deposits and sightings of volcanic plumes. Copyright 2003 by the American Geophysical Union.

  12. Dust transport into Martian polar latitudes

    NASA Technical Reports Server (NTRS)

    Murphy, J. R.; Pollack, J. B.

    1992-01-01

    The presence of suspended dust in the Martian atmosphere, and its return to the planet's surface, is implicated in the formation of the polar layered terrain and the dichotomy in perennial CO2 polar cap retention in the two hemispheres. A three dimensional model was used to study Martian global dust storms. The model accounts for the interactive feedbacks between the atmospheric thermal and dynamical states and an evolving radiatively active suspended dust load. Results from dust storm experiments, as well as from simulations in which there is interest in identifying the conditions under which surface dust lifting occurs at various locations and times, indicate that dust transport due to atmospheric eddy motions is likely to be important in the arrival of suspended dust at polar latitudes. The layered terrain in both polar regions of Mars is interpreted as the reality of cyclical episodes of volatile (CO2, H2O) and dust deposition.

  13. An application of active surface heating for augmenting lift and reducing drag of an airfoil

    NASA Technical Reports Server (NTRS)

    Maestrello, Lucio; Badavi, Forooz F.; Noonan, Kevin W.

    1988-01-01

    Application of active control to separated flow on the RC(6)-08 airfoil at high angle of attack by localized surface heating is numerically simulated by integrating the compressible 2-D nonlinear Navier-Stokes equation solver. Active control is simulated by local modification of the temperature boundary condition over a narrow strip of the upper surface of the airfoil. Both mean and perturbed profiles are favorably altered when excited with the same natural frequency of the shear layer by moderate surface heating for both laminar and turbulent separation. The shear layer is found to be very sensitive to localized surface heating in the vicinity of the separation point. The excitation field at the surface sufficiently altered both the local as well as the global circulation to cause a significant increase in lift and reduction in drag.

  14. Identification of ice nucleation active sites on feldspar dust particles.

    PubMed

    Zolles, Tobias; Burkart, Julia; Häusler, Thomas; Pummer, Bernhard; Hitzenberger, Regina; Grothe, Hinrich

    2015-03-19

    Mineral dusts originating from Earth's crust are known to be important atmospheric ice nuclei. In agreement with earlier studies, feldspar was found as the most active of the tested natural mineral dusts. Here we investigated in closer detail the reasons for its activity and the difference in the activity of the different feldspars. Conclusions are drawn from scanning electron microscopy, X-ray powder diffraction, infrared spectroscopy, and oil-immersion freezing experiments. K-feldspar showed by far the highest ice nucleation activity. Finally, we give a potential explanation of this effect, finding alkali-metal ions having different hydration shells and thus an influence on the ice nucleation activity of feldspar surfaces. PMID:25584435

  15. Identification of Ice Nucleation Active Sites on Feldspar Dust Particles

    PubMed Central

    2015-01-01

    Mineral dusts originating from Earth’s crust are known to be important atmospheric ice nuclei. In agreement with earlier studies, feldspar was found as the most active of the tested natural mineral dusts. Here we investigated in closer detail the reasons for its activity and the difference in the activity of the different feldspars. Conclusions are drawn from scanning electron microscopy, X-ray powder diffraction, infrared spectroscopy, and oil-immersion freezing experiments. K-feldspar showed by far the highest ice nucleation activity. Finally, we give a potential explanation of this effect, finding alkali-metal ions having different hydration shells and thus an influence on the ice nucleation activity of feldspar surfaces. PMID:25584435

  16. Perceived heaviness in the context of Newton's Second Law: Combined effects of muscle activity and lifting kinematics.

    PubMed

    Waddell, Morgan L; Fine, Justin M; Likens, Aaron D; Amazeen, Eric L; Amazeen, Polemnia G

    2016-03-01

    Researchers generally agree that perceived heaviness is based on the actions associated with unsupported holding. Psychophysical research has supported this idea, as has psychophysiological research connecting muscle activity to the perceptions of heaviness and effort. However, the role of muscle activity in the context of the resulting motions has not been investigated. In the present study, perceptions of heaviness were recorded along with the electromyogram (EMG) of the lifting muscle and peak acceleration of the lift. Consistent with predictions derived from Newton's Second Law of motion (Force=Mass × Acceleration), normal and illusory perceptions of heaviness were a function of the ratio of muscle activity to lifting acceleration. These results identify a psychophysiological mechanism for heaviness perception based on the forces and motions associated with unsupported holding.

  17. Lunar Dust and Lunar Simulant Activation and Monitoring

    NASA Technical Reports Server (NTRS)

    Wallace, W. T.; Hammond, D. K.; Jeevarajan, A. S.

    2008-01-01

    Prior to returning to the moon, understanding the effects of lunar dust on both human physiology and mechanical equipment is a pressing concern, as problems related to lunar dust during the Apollo missions have been well documented (J.R. Gaier, The Effects of Lunar Dust on EVA Systems During the Apollo Missions. 2005, NASA-Glenn Research Center. p. 65). While efforts were made to remove the dust before reentering the lunar module, via brushing of the suits or vacuuming, a significant amount of dust was returned to the spacecraft, causing various problems. For instance, astronaut Harrison Schmitt complained of hay fever effects caused by the dust, and the abrasive nature of the material was found to cause problems with various joints and seals of the spacecraft and suits. It is clear that, in order to avoid potential health and performance problems while on the lunar surface, the reactive properties of lunar dust must be quenched. It is likely that soil on the lunar surface is in an activated form, i.e. capable of producing oxygen-based radicals in a humidified air environment, due to constant exposure to meteorite impacts, UV radiation, and elements of the solar wind. An activated silica surface serves as a good example. An oxygen-based radical species arises from the breaking of Si-OSi bonds. This system is comparable to that expected for the lunar dust system due to the large amounts of agglutinic glass and silicate vapor deposits present in lunar soil. Unfortunately, exposure to the Earth s atmosphere has passivated the active species on lunar dust, leading to efforts to reactivate the dust in order to understand the true effects that will be experienced by astronauts and equipment on the moon. Electron spin resonance (ESR) spectroscopy is commonly used for the study of radical species, and has been used previously to study silicon- and oxygen-based radicals, as well as the hydroxyl radicals produced by these species in solution (V. Vallyathan, et al., Am. Rev

  18. Comparative evaluation of six quantitative lifting tools to estimate spine loads during static activities.

    PubMed

    Rajaee, Mohammad Ali; Arjmand, Navid; Shirazi-Adl, Aboulfazl; Plamondon, André; Schmidt, Hendrik

    2015-05-01

    Different lifting analysis tools are commonly used to assess spinal loads and risk of injury. Distinct musculoskeletal models with various degrees of accuracy are employed in these tools affecting thus their relative accuracy in practical applications. The present study aims to compare predictions of six tools (HCBCF, LSBM, 3DSSPP, AnyBody, simple polynomial, and regression models) for the L4-L5 and L5-S1 compression and shear loads in twenty-six static activities with and without hand load. Significantly different spinal loads but relatively similar patterns for the compression (R(2) > 0.87) were computed. Regression models and AnyBody predicted intradiscal pressures in closer agreement with available in vivo measurements (RMSE ≈ 0.12 MPa). Due to the differences in predicted spinal loads, the estimated risk of injury alters depending on the tool used. Each tool is evaluated to identify its shortcomings and preferred application domains.

  19. High-Lift System for a Supercritical Airfoil: Simplified by Active Flow Control

    NASA Technical Reports Server (NTRS)

    Melton, LaTunia Pack; Schaeffler, Norman W.; Lin, John C.

    2007-01-01

    Active flow control wind tunnel experiments were conducted in the NASA Langley Low-Turbulence Pressure Tunnel using a two-dimensional supercritical high-lift airfoil with a 15% chord hinged leading-edge flap and a 25% chord hinged trailing-edge flap. This paper focuses on the application of zero-net-mass-flux periodic excitation near the airfoil trailing edge flap shoulder at a Mach number of 0.1 and chord Reynolds numbers of 1.2 x 10(exp 6) to 9 x 10(exp 6) with leading- and trailing-edge flap deflections of 25 deg. and 30 deg., respectively. The purpose of the investigation was to increase the zero-net-mass-flux options for controlling trailing edge flap separation by using a larger model than used on the low Reynolds number version of this model and to investigate the effect of flow control at higher Reynolds numbers. Static and dynamic surface pressures and wake pressures were acquired to determine the effects of flow control on airfoil performance. Active flow control was applied both upstream of the trailing edge flap and immediately downstream of the trailing edge flap shoulder and the effects of Reynolds number, excitation frequency and amplitude are presented. The excitations around the trailing edge flap are then combined to control trailing edge flap separation. The combination of two closely spaced actuators around the trailing-edge flap knee was shown to increase the lift produced by an individual actuator. The phase sensitivity between two closely spaced actuators seen at low Reynolds number is confirmed at higher Reynolds numbers. The momentum input required to completely control flow separation on the configuration was larger than that available from the actuators used.

  20. The dust covering factor in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Stalevski, Marko; Ricci, Claudio; Ueda, Yoshihiro; Lira, Paulina; Fritz, Jacopo; Baes, Maarten

    2016-05-01

    The primary source of emission of active galactic nuclei (AGNs), the accretion disc, is surrounded by an optically and geometrically thick dusty structure (`the so-called dusty torus'). The infrared radiation emitted by the dust is nothing but a reprocessed fraction of the accretion disc emission, so the ratio of the torus to the AGN luminosity (Ltorus/LAGN) should corresponds to the fraction of the sky obscured by dust, i.e. the covering factor. We undertook a critical investigation of the Ltorus/LAGN as the dust covering factor proxy. Using state-of-the-art 3D Monte Carlo radiative transfer code, we calculated a grid of spectral energy distributions (SEDs) emitted by the clumpy two-phase dusty structure. With this grid of SEDs, we studied the relation between Ltorus/LAGN and the dust covering factor for different parameters of the torus. We found that in the case of type 1 AGNs the torus anisotropy makes Ltorus/LAGN underestimate low covering factors and overestimate high covering factors. In type 2 AGNs Ltorus/LAGN always underestimates covering factors. Our results provide a novel easy-to-use method to account for anisotropy and obtain correct covering factors. Using two samples from the literature, we demonstrated the importance of our result for inferring the obscured AGN fraction. We found that after the anisotropy is properly accounted for, the dust covering factors show very weak dependence on LAGN, with values in the range of ≈0.6-0.7. Our results also suggest a higher fraction of obscured AGNs at high luminosities than those found by X-ray surveys, in part owing to the presence of a Compton-thick AGN population predicted by population synthesis models.

  1. 75 FR 43228 - Bureau of Political-Military Affairs; Lifting of Policy of Denial Regarding Activities of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-23

    .../affiliates imposed on December 18, 2008 (73 FR 77099) pursuant to section 38 of the Arms Export Control Act... of Political-Military Affairs; Lifting of Policy of Denial Regarding Activities of Presidential... Defense Trade Controls Compliance, Bureau of Political-Military Affairs, Department of State (202)...

  2. Active Head Lifting from Supine in Early Infancy: An Indicator for Non-Optimal Cognitive Outcome in Late Infancy

    ERIC Educational Resources Information Center

    van Haastert, Ingrid C.; Groenendaal, Floris; van de Waarsenburg, Maria K.; Eijsermans, Maria J. C.; Koopman-Esseboom, Corine; Jongmans, Marian J.; Helders, Paul J. M.; de Vries, Linda S.

    2012-01-01

    Aim: To explore whether active head lifting from supine (AHLS) in early infancy is associated with cognitive outcome in the second year of life. Method: The presence of AHLS was always recorded in the notes of infants admitted to our tertiary neonatal intensive care unit. Random sampling was used to pair infants with AHLS with two comparison…

  3. Fluorescence-Based Sensor for Monitoring Activation of Lunar Dust

    NASA Technical Reports Server (NTRS)

    Wallace, William T.; Jeevarajan, Antony S.

    2012-01-01

    This sensor unit is designed to determine the level of activation of lunar dust or simulant particles using a fluorescent technique. Activation of the surface of a lunar soil sample (for instance, through grinding) should produce a freshly fractured surface. When these reactive surfaces interact with oxygen and water, they produce hydroxyl radicals. These radicals will react with a terephthalate diluted in the aqueous medium to form 2-hydroxyterephthalate. The fluorescence produced by 2-hydroxyterephthalate provides qualitative proof of the activation of the sample. Using a calibration curve produced by synthesized 2-hydroxyterephthalate, the amount of hydroxyl radicals produced as a function of sample concentration can also be determined.

  4. Effects of lifting the non-paretic foot on muscle activity during the semi-squat exercise in hemiplegic patients.

    PubMed

    Lee, Dong-Kyu; Yu, Il-Young; Jung, In-Gui; Oh, Jae-Seop

    2015-06-01

    [Purpose] This study compared the electromyographic activity of the quadriceps in hemiplegic patients during the downward, maintenance, and upward phases of squat exercises performed with the feet parallel and with the non-paretic foot lifted. [Subjects] A total of 17 hemiplegic patients (9 males and 8 females) volunteered for this study. [Methods] All subjects performed squat exercises with the knees flexed to 30° and with the feet parallel (shoulder-width apart) or with lifting of the non-paretic foot (normalized to 25% of the knee height). [Results] The activity of the rectus femoris, vastus medialis oblique, and vastus lateralis muscles was significantly higher during squat exercises performed with the non-paretic foot lifted than with the feet parallel to each other. The activity of all muscles during the maintenance phase of the exercises was greater than that during the downward and upward phases. [Conclusion] Lifting the non-paretic foot during squats may represent an effective exercise for motor function rehabilitation in hemiplegic patients.

  5. Dust and ionized gas in active radio elliptical galaxies

    NASA Technical Reports Server (NTRS)

    Forbes, D. A.; Sparks, W. B.; Macchetto, F. D.

    1990-01-01

    The authors present broad and narrow bandwidth imaging of three southern elliptical galaxies which have flat-spectrum active radio cores (NGC 1052, IC 1459 and NGC 6958). All three contain dust and extended low excitation optical line emission, particularly extensive in the case of NGC 1052 which has a large H alpha + (NII) luminosity. Both NGC 1052 and IC 1459 have a spiral morphology in emission-line images. All three display independent strong evidence that a merger or infall event has recently occurred, i.e., extensive and infalling HI gas in NGC 1052, a counter-rotating core in IC 1459 and Malin-Carter shells in NGC 6958. This infall event is the most likely origin for the emission-line gas and dust, and the authors are currently investigating possible excitation mechanisms (Sparks et al. 1990).

  6. Active dust devils in Gusev crater, Mars: Observations from the Mars Exploration Rover Spirit

    USGS Publications Warehouse

    Greeley, R.; Whelley, P.L.; Arvidson, R. E.; Cabrol, N.A.; Foley, D.J.; Franklin, B.J.; Geissler, P.G.; Golombek, M.P.; Kuzmin, R.O.; Landis, G.A.; Lemmon, M.T.; Neakrase, L.D.V.; Squyres, S. W.; Thompson, S.D.

    2006-01-01

    A full dust devil "season" was observed from Spirit from 10 March 2005 (sol 421, first active dust devil observed) to 12 December 2005 (sol 691, last dust devil seen); this corresponds to the period Ls 173.2?? to 339.5??, or the southern spring and summer on Mars. Thermal Emission Spectrometer data suggest a correlation between high surface temperatures and a positive thermal gradient with active dust devils in Gusev and that Spirit landed in the waning stages of a dust devil season as temperatures decreased. 533 active dust devils were observed, enabling new characterizations; they ranged in diameter from 2 to 276 m, with most in the range of 10-20 m in diameter, and occurred from about 0930 to 1630 hours local true solar time (with the maximum forming around 1300 hours) and a peak occurrence in southern late spring (Ls ??? 250??). Horizontal speeds of the dust devils ranged from <1 to 21 m/s, while vertical wind speeds within the dust devils ranged from 0.2 to 8.8 m/s. These data, when combined with estimates of the dust content within the dust devils, yield dust fluxes of 3.95 ?? 10-9 to 4.59-4 kg/m2/s. Analysis of the dust devil frequency distribution over the inferred dust devil zone within Gusev crater yields ???50 active dust devils/km2/sol, suggesting a dust loading into the atmosphere of ???19 kg/km2/sol. This value is less than one tenth the estimates by Cantor et al. (2001) for regional dust storms on Mars. Copyright 2006 by the American Geophysical Union.

  7. Active Dust Mitigation Technology for Thermal Radiators for Lunar Exploration

    NASA Technical Reports Server (NTRS)

    Calle, C. I.; Buhler, C. R.; Hogue, M. D.; Johansen, M. R.; Hopkins, J. W.; Holloway, N. M. H.; Connell, J. W.; Chen, A.; Irwin, S. A.; Case, S. O.; VanSuetendael, N. J.; Snyder, S. J.; Clements, J. S.

    2010-01-01

    Dust accumulation on thermal radiator surfaces planned for lunar exploration will significantly reduce their efficiency. Evidence from the Apollo missions shows that an insulating layer of dust accumulated on radiator surfaces could not be removed and caused serious thermal control problems. Temperatures measured at different locations in the magnetometer on Apollo 12 were 38 C warmer than expected due to lunar dust accumulation. In this paper, we report on the application of the Electrodynamic Dust Shield (EDS) technology being developed in our NASA laboratory and applied to thermal radiator surfaces. The EDS uses electrostatic and dielectrophoretic forces generated by a grid of electrodes running a 2 micro A electric current to remove dust particles from surfaces. Working prototypes of EDS systems on solar panels and on thermal radiators have been successfully developed and tested at vacuum with clearing efficiencies above 92%. For this work EDS prototypes on flexible and rigid thermal radiators were developed and tested at vacuum.

  8. Detection of dust aerosol by combining CALIPSO active lidar and passive IIR measurements

    NASA Astrophysics Data System (ADS)

    Chen, B.; Huang, J.; Minnis, P.; Hu, Y.; Yi, Y.; Liu, Z.; Zhang, D.; Wang, X.

    2010-02-01

    The version 2 Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) dust layer detection method, which is based only on lidar measurements, misclassified about 43% dust layers (mainly dense dust layer) as cloud layers over the Taklamakan Desert. To address this problem, a new method was developed by combining the CALIPSO Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and passive Infrared Imaging Radiometer (IIR) measurements. This combined lidar and IR measurement (hereafter, CLIM) method uses the IIR tri-spectral IR brightness temperatures to discriminate between ice cloud and dense dust layers, and lidar measurements alone to detect thin dust and water cloud layers. The brightness temperature difference between 10.60 and 12.05 μm (BTD11-12) is typically negative for dense dust and generally positive for ice cloud, but it varies from negative to positive for thin dust layers, which the CALIPSO lidar correctly identifies. Results show that the CLIM method could significantly reduce misclassification rates to as low as ~7% for the active dust season of spring 2008 over the Taklamakan Desert. The CLIM method also revealed 18% more dust layers having greatly intensified backscatter between 1.8 and 4 km altitude over the source region compared to the CALIPSO version 2 data. These results allow a more accurate assessment of the effect of dust on climate.

  9. Detection of dust aerosol by combining CALIPSO active lidar and passive IIR measurements

    NASA Astrophysics Data System (ADS)

    Chen, B.; Huang, J.; Minnis, P.; Hu, Y.; Yi, Y.; Liu, Z.; Zhang, D.; Wang, X.

    2010-05-01

    The version 2 Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) dust layer detection method, which is based only on lidar measurements, misclassified about 43% dust layers (mainly dense dust layers) as cloud layers over the Taklamakan Desert. To address this problem, a new method was developed by combining the CALIPSO Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and passive Infrared Imaging Radiometer (IIR) measurements. This combined lidar and IR measurement (hereafter, CLIM) method uses the IIR tri-spectral IR brightness temperatures to discriminate between ice cloud and dense dust layers, and lidar measurements alone to detect thin dust and water cloud layers. The brightness temperature difference between 10.60 and 12.05 μm (BTD11-12) is typically negative for dense dust and generally positive for ice cloud, but it varies from negative to positive for thin dust layers, which the CALIPSO lidar correctly identifies. Results show that the CLIM method could significantly reduce misclassification rates to as low as ~7% for the active dust season of spring 2008 over the Taklamakan Desert. The CLIM method also revealed 18% more dust layers having greatly intensified backscatter between 1.8 and 4 km altitude over the source region compared to the CALIPSO version 2 data. These results allow a more accurate assessment of the effect of dust on climate.

  10. Dust Devils Seen by Spirit

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1 Annotated

    At the Gusev site recently, skies have been very dusty, and on its 421st sol (March 10, 2005) NASA's Mars Exploration Rover Spirit spied two dust devils in action. This pair of images is from the rover's rear hazard-avoidance camera. Views of the Gusev landing region from orbit show many dark streaks across the landscape -- tracks where dust devils have removed surface dust to show relatively darker soil below -- but this is the first time Spirit has photographed an active dust devil.

    Scientists are considering several causes of these small phenomena. Dust devils often occur when the Sun heats the surface of Mars. Warmed soil and rocks heat the layer of atmosphere closest to the surface, and the warm air rises in a whirling motion, stirring dust up from the surface like a miniature tornado. Another possibility is that a flow structure might develop over craters as wind speeds increase. As winds pick up, turbulence eddies and rotating columns of air form. As these columns grow in diameter they become taller and gain rotational speed. Eventually they become self-sustaining and the wind blows them down range.

    One sol before this image was taken, power output from Spirit's solar panels went up by about 50 percent when the amount of dust on the panels decreased. Was this a coincidence, or did a helpful dust devil pass over Spirit and lift off some of the dust?

    By comparing the separate images from the rover's different cameras, team members estimate that the dust devils moved about 500 meters (1,640 feet) in the 155 seconds between the navigation camera and hazard-avoidance camera frames; that equates to about 3 meters per second (7 miles per hour). The dust devils appear to be about 1,100 meters (almost three-quarters of a mile) from the rover.

  11. The Correlation between the Muscle Activity and Joint Angle of the Lower Extremity According to the Changes in Stance Width during a Lifting Task

    PubMed Central

    Yoon, Jung-Gyu

    2013-01-01

    [Purpose] This study examined the correlation between the muscle activities and joint angle of the hip and knee according to the changes in stance width during a lifting task. [Subjects and Methods] The subjects of this study were 15 healthy students. A three-dimensional motion analyzer (SMART-E, BTS, Italy) was used to measure the joint angles of hip and knee during lifting. An 8-channel electromyograph (8-EMG) (Pocket EMG, BTS, Italy) was used to measure muscle activities of the erector spinae, gluteus maximus, rectus femoris, and tibialis anterior during lifting. The collected data were analyzed using the Pearson-test and SPSS 18.0. [Result] The muscle activity of the tibialis anterior was significantly decreased by increasing the stance width (r= −0.285). Muscle activity of the erector spinae was significantly decreased by increasing the knee angle (r= −0.444). The muscle activity of the gluteus maximus was significantly increased by increasing the muscle activity of the tibialis anterior (r= 0.295). [Conclusion] Efficient lifting is possible when stance width and knee flexion are increased, which results in reduced muscle activity of the tibialis anterior and the erector spinae. Lifting is facilitated when the muscle activities of the gluteus maximus and tibialis anterior are correlated. PMID:24259908

  12. Climatic controls on the interannual to decadal variability in Saudi Arabian dust activity: Toward the development of a seasonal dust prediction model

    NASA Astrophysics Data System (ADS)

    Yu, Yan; Notaro, Michael; Liu, Zhengyu; Wang, Fuyao; Alkolibi, Fahad; Fadda, Eyad; Bakhrjy, Fawzieh

    2015-03-01

    The observed climatic controls on springtime and summertime Saudi Arabian dust activities during 1975-2012 are analyzed, leading to development of a seasonal dust prediction model. According to empirical orthogonal function analysis, dust storm frequency exhibits a dominantly homogeneous pattern across Saudi Arabia, with distinct interannual and decadal variability. The previously identified positive trend in remotely sensed aerosol optical depth since 2000 is shown to be a segment of the decadal oscillation in dust activity, according to long-duration station record. Regression and correlation analyses reveal that the interannual variability in Saudi Arabian dust storm frequency is regulated by springtime rainfall across the Arabian Peninsula and summertime Shamal wind intensity. The key drivers of Saudi Arabian dust storm variability are identified. Winter-to-spring La Niña enhances subsequent spring dust activity by decreasing rainfall across the country's primary dust source region, the Rub' al Khali Desert. A relatively cool tropical Indian Ocean favors frequent summer dust storms by producing an anomalously anticyclonic circulation over the central Arabian Peninsula, which enhances the Shamal wind. Decadal variability in Saudi Arabian dust storm frequency is associated with North African rainfall and Sahel vegetation, which regulate African dust emissions and transport to Saudi Arabia. Mediterranean sea surface temperatures (SSTs) also regulate decadal dust variability, likely through their influence on Sahel rainfall and Shamal intensity. Using antecedent-accumulated rainfall over the Arabian Peninsula and North Africa, and Mediterranean SSTs, as low-frequency predictors, and tropical eastern Pacific and tropical Indian Ocean SSTs as high-frequency predictors, Saudi Arabia's seasonal dust activity is well predicted.

  13. Activation of aryl hydrocarbon receptor signaling by extracts of teak and other wood dusts.

    PubMed

    Wilson, Mark J; Sabbioni, Gabriele; Rando, Roy; Miller, Charles A

    2015-12-01

    Wood dusts, as a group, are categorized as known human carcinogens, but the risks of exposure to specific types of wood dusts and the carcinogenic chemicals they contain are not well studied. Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that is linked to the carcinogenic action of specific classes of chemicals. Here we examined whether chemicals in various wood dusts had the potential to activate AhR signaling as a potential toxic mechanism of action. We found that methanol extracts of teak, walnut, mahogany, and poplar dusts contained a wide range of AhR ligand activity, whereas extracts of oak, pine, and other softwoods did not contain appreciable activity. Teak dust extract, being particularly potent, was subjected to chemical analysis. The 2-methylanthraquinone (2-MAQ) accounted for the AhR ligand activity and was present at an average concentration of 0.27 parts per hundred in teak dust. Pure 2-MAQ potently induced AhR signaling (EC50 115 nM), confirming that this was the active ligand. Aqueous extracts of teak dust made using yeast or mammalian cell culture medium also contained robust AhR activity, suggesting the 2-MAQ ligand is soluble at bioactive concentrations in physiologically relevant fluids. The high concentration and potency of 2-MAQ in teak wood suggest it may mediate toxic effects through activation of AhR signaling in exposed wood workers.

  14. In-situ measurement of dust devil activity at La Jornada Experimental Range, New Mexico, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We document observations of dust devil vortices using a linear array of 10 miniature pressure- and sunlight-logging stations in summer 2013 at La Jornada Experimental Range in the southwestern USA. These data provide a census of vortex and dust-devil activity at this site. The simultaneous spatial...

  15. Investigating Dust-less Devils at Gale Crater

    NASA Astrophysics Data System (ADS)

    Steakley, Kathryn; Murphy, James R.

    2014-11-01

    Understanding the frequency of and conditions that facilitate dust devil activity on Mars are key questions in determining whether convective vortices that lift dust are the main contributors to background dust opacity. Using pressure data from the Rover Environmental Monitoring Station (REMS) in Gale Crater, we detect approximately 200 convective vortices during the first 583 sols of the Mars Science Lab (MSL) mission. Most of these events do not have corresponding decreases in UV flux, which suggests that they are mainly dustless. Pressure drop magnitudes for the detections range from 0.31 - 2.86 pascals and 0.037 - 0.330% of ambient pressure. A rough approximation of the pressure drop required to lift dust can be made by assuming the vortices are in cyclostrophic balance (Sinclair, J. Atmos. Sci. 30, 1599, 1973) and that the tangential wind velocity threshold for particle lifting on Mars is between 12 and 40 m/s depending on particle size (Greeley et al., JGR 108, 5041, 2003). We estimate that under the right meteorological conditions at Gale Crater, the very smallest pressure drop that could lift particles is around ~2 pascals, suggesting that the majority of our detections are not strong enough for significant lifting. Further investigation of the local climate and drivers of convection within Gale Crater could explain why these vortices are relatively dustless and weak in magnitude.

  16. Serrated-Planform Lifting-Surfaces

    NASA Technical Reports Server (NTRS)

    McGrath, Brian E. (Inventor); Wood, Richard M. (Inventor)

    1999-01-01

    A novel set of serrated-planform lifting surfaces produce unexpectedly high lift coefficients at moderate to high angles-of-attack. Each serration, or tooth, is designed to shed a vortex. The interaction of the vortices greatly enhances the lifting capability over an extremely large operating range. Variations of the invention use serrated-planform lifting surfaces in planes different than that of a primary lifting surface. In an alternate embodiment, the individual teeth are controllably retractable and deployable to provide for active control of the vortex system and hence lift coefficient. Differential lift on multiple serrated-planform lifting surfaces provides a means for vehicle control. The important aerodynamic advantages of the serrated-planform lifting surfaces are not limited to aircraft applications but can be used to establish desirable performance characteristics for missiles, land vehicles, and/or watercraft.

  17. SEASONAL EFFECTS ON COMET NUCLEI EVOLUTION: ACTIVITY, INTERNAL STRUCTURE, AND DUST MANTLE FORMATION

    SciTech Connect

    De Sanctis, M. C.; Capria, M. T.; Lasue, J.

    2010-07-15

    Rotational properties can strongly influence a comet's evolution in terms of activity, dust mantling, and internal structure. In this paper, we investigate the effects of various rotation axis directions on the activity, internal structure, and dust mantling of cometary nuclei. The numerical code developed is able to reproduce different shapes and spin axis inclinations, taking into account both the latitudinal and the longitudinal variations of illumination, using a quasi-three-dimensional approach. The results obtained show that local variations in the dust and gas fluxes can be induced by the different spin axis directions and completely different behaviors of the comet evolution can result in the same cometary shape by using different obliquities of the models. The internal structures of cometary nuclei are also influenced by comet obliquity, as well as dust mantling. Gas and dust production rates show diversities related to the comet seasons.

  18. Understanding the Activation and Solution Properties of Lunar Dust for Future Lunar Habitation

    NASA Technical Reports Server (NTRS)

    Wallace, William T.; Jeevarajan, Antony S.

    2009-01-01

    The decision to return humans to the moon by 2020 makes it imperative to understand the effects of lunar dust on human and mechanical systems.( Bush 2004; Gaier 2005; Mendell 2005) During the Apollo missions, dust was found to cause numerous problems for various instruments and systems. Additionally, the dust may have caused health issues for some of the astronauts.(Gaier 2005; Rowe 2007) It is necessary, therefore, for studies to be carried out in a variety of disciplines in order to mitigate the effects of the dust as completely as possible. Due to the lack of an atmosphere, there is nothing to protect the lunar soil from ultraviolet radiation, solar wind, and meteorite impacts. These processes could all serve to "activate" the soil, or produce reactive surface species. In order to understand the possible toxic effects of the reactive dust, it is necessary to "reactivate" the dust, as samples returned during the Apollo missions were exposed to the atmosphere of the Earth. We have used grinding and exposure to UV radiation in order to mimic some of the processes occurring on the lunar surface. To monitor the reactivity of the dust, we have measured the ability of the dust to produce hydroxyl radicals in solution. These radicals have been measured using a novel fluorescent technique developed in our laboratory,(Wallace et al. 2008) as well as using electron paramagnetic resonance (EPR).

  19. Direct activation of gelatinase B (MMP-9) by hay dust suspension and different components of organic dust.

    PubMed

    Simonen-Jokinen, Terhi; Maisi, Päivi; Tervahartiala, Taina; McGorum, Bruce; Pirie, Scott; Sorsa, Timo

    2006-02-15

    Matrix metalloproteinases (MMPs) are involved in tissue destruction in allergic airway diseases. We studied the ability of various allergenic substances to directly activate recombinant 92kDa proMMP-9. The substances included hay dust suspension (HDS) and its components (supernatant, particulate matter and wash fluid of particulate matter), storage mite extract and two Aspergillus fumigatus extracts. The allergen suspensions were incubated in vitro with proMMP-9. After incubation the conversion of proMMP-9 to 10kDa lower active forms were studied using gelatin zymography and Western immunoblot quantified by computerized densitometry. All studied allergens except HDS significantly and efficiently activated proMMP-9 as compared to a negative control. At the concentrations employed, the most potent activators were A. fumigatus extracts and mite suspension. The greater potency of mite and fungi as proMMP-9 activators suggests that these allergens may be more damaging to airways even at low concentrations. PMID:16181685

  20. Cytotoxic Effects of Re-Activated Lunar Dust Stimulant on Human Lung Cells

    NASA Technical Reports Server (NTRS)

    Upadhyaya, Krishna

    2009-01-01

    Lunar dust has been of significant concern due to various problems observed on the Apollo missions. Reports from astronauts have shown that the dust may have caused eye and nasal irritation as well as possible hay fever like symptoms. As NASA hopes to go to the Moon within the next few years, we hope to understand the possible toxic effects the dust might have. In these studies, we are looking at the effect of "re-activated" lunar dust stimulant on human bronchial cells. A simple grinding analog as a method of simulating micrometeorite crushing on the moon is used to "activate" the dust stimulant, i.e. capable of producing hydroxyl radicals. These radicals could then interact with human cells and may lead to a loss in membrane integrity and cell death. (Castranova, 1994) Cells are exposed to the dust for 6 and 24 hour intervals to assess cytotoxicity. Cytotoxicity is measured by looking at the production of inflammatory cytokines. Cells are exposed to ground and unground stimulant and compared to cytokine production from cells exposed to quartz which have a known toxicity. Here we look at the cytotoxicity of the lunar dust stimulant relative to quartz by measuring the production of inflammatory cytokines.

  1. Combined hydrolysis acidification and bio-contact oxidation system with air-lift tubes and activated carbon bioreactor for oilfield wastewater treatment.

    PubMed

    Guo, Chunmei; Chen, Yi; Chen, Jinfu; Wang, Xiaojun; Zhang, Guangqing; Wang, Jingxiu; Cui, Wenfeng; Zhang, Zhongzhi

    2014-10-01

    This paper investigated the enhancement of the COD reduction of an oilfield wastewater treatment process by installing air-lift tubes and adding an activated carbon bioreactor (ACB) to form a combined hydrolysis acidification and bio-contact oxidation system with air-lift tubes (HA/air-lift BCO) and an ACB. Three heat-resistant bacterial strains were cultivated and subsequently applied in above pilot plant test. Installing air-lift tubes in aerobic tanks reduced the necessary air to water ratio from 20 to 5. Continuous operation of the HA/air-lift BCO system for 2 months with a hydraulic retention time of 36 h, a volumetric load of 0.14 kg COD/(m(3)d) (hydrolysis-acidification or anaerobic tank), and 0.06 kg COD/(m(3)d) (aerobic tanks) achieved an average reduction of COD by 60%, oil and grease by 62%, total suspended solids by 75%, and sulfides by 77%. With a COD load of 0.56 kg/(m(3)d), the average COD in the ACB effluent was 58 mg/L.

  2. Lunar Dust and Lunar Simulant Activation, Monitoring, Solution and Cellular Toxicity Properties

    NASA Technical Reports Server (NTRS)

    Wallace, William; Jeevarajan, A. S.

    2009-01-01

    During the Apollo missions, many undesirable situations were encountered that must be mitigated prior to returning humans to the moon. Lunar dust (that part of the lunar regolith less than 20 microns in diameter) was found to produce several problems with mechanical equipment and could have conceivably produced harmful physiological effects for the astronauts. For instance, the abrasive nature of the dust was found to cause malfunctions of various joints and seals of the spacecraft and suits. Additionally, though efforts were made to exclude lunar dust from the cabin of the lunar module, a significant amount of material nonetheless found its way inside. With the loss of gravity correlated with ascent from the lunar surface, much of the finer fraction of this dust began to float and was inhaled by the astronauts. The short visits tothe Moon during Apollo lessened exposure to the dust, but the plan for future lunar stays of up to six months demands that methods be developed to minimize the risk of dust inhalation. The guidelines for what constitutes "safe" exposure will guide the development of engineering controls aimed at preventing the presence of dust in the lunar habitat. This work has shown the effects of grinding on the activation level of lunar dust, the changes in dissolution properties of lunar simulant, and the production of cytokines by cellular systems. Grinding of lunar dust leads to the production of radicals in solution and increased dissolution of lunar simulant in buffers of different pH. Additionally, ground lunar simulant has been shown to promote the production of IL-6 and IL-8, pro-inflammatory cytokines, by alveolar epithelial cells. These results provide evidence of the need for further studies on these materials prior to returning to the lunar surface.

  3. Total Facelift: Forehead Lift, Midface Lift, and Neck Lift

    PubMed Central

    2015-01-01

    Patients with thick skin mainly exhibit the aging processes of sagging, whereas patients with thin skin develop wrinkles or volume loss. Asian skin is usually thicker than that of Westerners; and thus, the sagging of skin due to aging, rather than wrinkling, is the chief problem to be addressed in Asians. Asian skin is also relatively large in area and thick, implying that the weight of tissue to be lifted is considerably heavier. These factors account for the difficulties in performing a facelift in Asians. Facelifts can be divided into forehead lift, midface lift, and lower face lift. These can be performed individually or with 2-3 procedures combined. PMID:25798381

  4. RADIOLOGICAL RELEASES DUE TO AIR AND SILICA DUST ACTIVATION IN EMPLACEMENT DRIFTS

    SciTech Connect

    J.S. Tang

    2003-05-07

    The purpose of this calculation is to determine the quantity and significance of annual Monitored Geologic Repository (MGR) subsurface normal radiological releases due to neutron activation of air and silica dust in emplacement drifts. This calculation includes the following items: (1) Calculate activation of ventilation airflow through emplacement drifts to quantify radioactive gaseous releases; and (2) Calculate the bounding potential activated silica dust concentration and releases. The sources of silica dust may arise from air supply to emplacement drifts as well as host rock around emplacement drifts. For this calculation, the source of dust is conservatively assumed to be the host rock (Assumption 3.6), which is subject to long-term neutron exposure resulting in saturated radioactivity. The scope of this calculation is limited to releases from activated air and silica dust only, excluding natural radioactive releases such as radon or releases from defective waste packages (breached or contaminated). This work supports the repository ventilation system design and Preclosure Safety Analysis. This includes MGR items classified as Quality Level 1, for example, the Uncanistered Spent Nuclear Fuel Waste Package (CRWMS M&O [Civilian Radioactive Waste Management and Operation Contractor] 1999a, page 7). Therefore, this calculation is subject to the requirements of the ''Quality Assurance Requirements and Description'' (DOE [U.S. Department of Energy] 2003). The performance of the calculation and development of this document are carried out in accordance with AP-3.12Q, ''Design Calculation and Analyses'' and LP-3.30Q-BSC, ''Hazards Analysis System''.

  5. Grain physics and infrared dust emission in active galactic nucleus environments

    SciTech Connect

    Hensley, Brandon S.; Ostriker, Jeremiah P.; Ciotti, Luca

    2014-07-01

    We study the effects of a detailed dust treatment on the properties and evolution of early-type galaxies containing central black holes, as determined by active galactic nucleus (AGN) feedback. We find that during cooling flow episodes, radiation pressure on the dust in and interior to infalling shells of cold gas can greatly impact the amount of gas able to be accreted and therefore the frequency of AGN bursts. However, the overall hydrodynamic evolution of all models, including mass budget, is relatively robust to the assumptions on dust. We find that IR re-emission from hot dust can dominate the bolometric luminosity of the galaxy during the early stages of an AGN burst, reaching values in excess of 10{sup 46} erg s{sup –1}. The AGN-emitted UV is largely absorbed, but the optical depth in the IR does not exceed unity, so the radiation momentum input never exceeds L {sub BH}/c. We constrain the viability of our models by comparing the AGN duty cycle, broadband luminosities, dust mass, black hole mass, and other model predictions to current observations. These constraints force us towards models wherein the dust to metals ratios are ≅ 1% of the Galactic value, and only models with a dynamic dust to gas ratio are able to produce both quiescent galaxies consistent with observations and high obscured fractions during AGN 'on' phases. During AGN outbursts, we predict that a large fraction of the FIR luminosity can be attributed to warm dust emission (≅ 100 K) from dense dusty gas within ≤1 kpc reradiating the AGN UV emission.

  6. Development of weight and cost estimates for lifting surfaces with active controls

    NASA Technical Reports Server (NTRS)

    Anderson, R. D.; Flora, C. C.; Nelson, R. M.; Raymond, E. T.; Vincent, J. H.

    1976-01-01

    Equations and methodology were developed for estimating the weight and cost incrementals due to active controls added to the wing and horizontal tail of a subsonic transport airplane. The methods are sufficiently generalized to be suitable for preliminary design. Supporting methodology and input specifications for the weight and cost equations are provided. The weight and cost equations are structured to be flexible in terms of the active control technology (ACT) flight control system specification. In order to present a self-contained package, methodology is also presented for generating ACT flight control system characteristics for the weight and cost equations. Use of the methodology is illustrated.

  7. Proteases in agricultural dust induce lung inflammation through PAR-1 and PAR-2 activation.

    PubMed

    Romberger, Debra J; Heires, Art J; Nordgren, Tara M; Souder, Chelsea P; West, William; Liu, Xiang-de; Poole, Jill A; Toews, Myron L; Wyatt, Todd A

    2015-08-15

    Workers exposed to aerosolized dust present in concentrated animal feeding operations (CAFOs) are susceptible to inflammatory lung diseases, such as chronic obstructive pulmonary disease. Extracts of dust collected from hog CAFOs [hog dust extract (HDE)] are potent stimulators of lung inflammatory responses in several model systems. The observation that HDE contains active proteases prompted the present study, which evaluated the role of CAFO dust proteases in lung inflammatory processes and tested whether protease-activated receptors (PARs) are involved in the signaling pathway for these events. We hypothesized that the damaging proinflammatory effect of HDE is due, in part, to the proteolytic activation of PARs, and inhibiting the proteases in HDE or disrupting PAR activation would attenuate HDE-mediated inflammatory indexes in bronchial epithelial cells (BECs), in mouse lung slices in vitro, and in a murine in vivo exposure model. Human BECs and mouse lung slice cultures stimulated with 5% HDE released significantly more of each of the cytokines measured (IL-6, IL-8, TNF-α, keratinocyte-derived chemokine/CXC chemokine ligand 1, and macrophage inflammatory protein-2/CXC chemokine ligand 2) than controls, and these effects were markedly diminished by protease inhibition. Inhibition of PARs also blunted the HDE-induced cytokine release from BECs. In addition, protease depletion inhibited HDE-induced BEC intracellular PKCα and PKCε activation. C57BL/6J mice administered 12.5% HDE intranasally, either once or daily for 3 wk, exhibited increased total cellular and neutrophil influx, bronchial alveolar fluid inflammatory cytokines, lung histopathology, and inflammatory scores compared with mice receiving protease-depleted HDE. These data suggest that proteases in dust from CAFOs are important mediators of lung inflammation, and these proteases and their receptors may provide novel targets for therapeutic intervention in CAFO dust-induced airways disease.

  8. Proteases in agricultural dust induce lung inflammation through PAR-1 and PAR-2 activation.

    PubMed

    Romberger, Debra J; Heires, Art J; Nordgren, Tara M; Souder, Chelsea P; West, William; Liu, Xiang-de; Poole, Jill A; Toews, Myron L; Wyatt, Todd A

    2015-08-15

    Workers exposed to aerosolized dust present in concentrated animal feeding operations (CAFOs) are susceptible to inflammatory lung diseases, such as chronic obstructive pulmonary disease. Extracts of dust collected from hog CAFOs [hog dust extract (HDE)] are potent stimulators of lung inflammatory responses in several model systems. The observation that HDE contains active proteases prompted the present study, which evaluated the role of CAFO dust proteases in lung inflammatory processes and tested whether protease-activated receptors (PARs) are involved in the signaling pathway for these events. We hypothesized that the damaging proinflammatory effect of HDE is due, in part, to the proteolytic activation of PARs, and inhibiting the proteases in HDE or disrupting PAR activation would attenuate HDE-mediated inflammatory indexes in bronchial epithelial cells (BECs), in mouse lung slices in vitro, and in a murine in vivo exposure model. Human BECs and mouse lung slice cultures stimulated with 5% HDE released significantly more of each of the cytokines measured (IL-6, IL-8, TNF-α, keratinocyte-derived chemokine/CXC chemokine ligand 1, and macrophage inflammatory protein-2/CXC chemokine ligand 2) than controls, and these effects were markedly diminished by protease inhibition. Inhibition of PARs also blunted the HDE-induced cytokine release from BECs. In addition, protease depletion inhibited HDE-induced BEC intracellular PKCα and PKCε activation. C57BL/6J mice administered 12.5% HDE intranasally, either once or daily for 3 wk, exhibited increased total cellular and neutrophil influx, bronchial alveolar fluid inflammatory cytokines, lung histopathology, and inflammatory scores compared with mice receiving protease-depleted HDE. These data suggest that proteases in dust from CAFOs are important mediators of lung inflammation, and these proteases and their receptors may provide novel targets for therapeutic intervention in CAFO dust-induced airways disease. PMID

  9. Proteases in agricultural dust induce lung inflammation through PAR-1 and PAR-2 activation

    PubMed Central

    Heires, Art J.; Nordgren, Tara M.; Souder, Chelsea P.; West, William; Liu, Xiang-de; Poole, Jill A.; Toews, Myron L.; Wyatt, Todd A.

    2015-01-01

    Workers exposed to aerosolized dust present in concentrated animal feeding operations (CAFOs) are susceptible to inflammatory lung diseases, such as chronic obstructive pulmonary disease. Extracts of dust collected from hog CAFOs [hog dust extract (HDE)] are potent stimulators of lung inflammatory responses in several model systems. The observation that HDE contains active proteases prompted the present study, which evaluated the role of CAFO dust proteases in lung inflammatory processes and tested whether protease-activated receptors (PARs) are involved in the signaling pathway for these events. We hypothesized that the damaging proinflammatory effect of HDE is due, in part, to the proteolytic activation of PARs, and inhibiting the proteases in HDE or disrupting PAR activation would attenuate HDE-mediated inflammatory indexes in bronchial epithelial cells (BECs), in mouse lung slices in vitro, and in a murine in vivo exposure model. Human BECs and mouse lung slice cultures stimulated with 5% HDE released significantly more of each of the cytokines measured (IL-6, IL-8, TNF-α, keratinocyte-derived chemokine/CXC chemokine ligand 1, and macrophage inflammatory protein-2/CXC chemokine ligand 2) than controls, and these effects were markedly diminished by protease inhibition. Inhibition of PARs also blunted the HDE-induced cytokine release from BECs. In addition, protease depletion inhibited HDE-induced BEC intracellular PKCα and PKCε activation. C57BL/6J mice administered 12.5% HDE intranasally, either once or daily for 3 wk, exhibited increased total cellular and neutrophil influx, bronchial alveolar fluid inflammatory cytokines, lung histopathology, and inflammatory scores compared with mice receiving protease-depleted HDE. These data suggest that proteases in dust from CAFOs are important mediators of lung inflammation, and these proteases and their receptors may provide novel targets for therapeutic intervention in CAFO dust-induced airways disease. PMID

  10. The lift-fan powered-lift aircraft concept: Lessons learned

    NASA Technical Reports Server (NTRS)

    Deckert, Wallace H.

    1993-01-01

    This is one of a series of reports on the lessons learned from past research related to lift-fan aircraft concepts. An extensive review is presented of the many lift-fan aircraft design studies conducted by both government and industry over the past 45 years. Mission applications and design integration including discussions on manifolding hot gas generators, hot gas dusting, and energy transfer control are addressed. Past lift-fan evaluations of the Avrocar are discussed. Lessons learned from these past efforts are identified.

  11. Variable Lifting Index (VLI)

    PubMed Central

    Waters, Thomas; Occhipinti, Enrico; Colombini, Daniela; Alvarez-Casado, Enrique; Fox, Robert

    2015-01-01

    Objective: We seek to develop a new approach for analyzing the physical demands of highly variable lifting tasks through an adaptation of the Revised NIOSH (National Institute for Occupational Safety and Health) Lifting Equation (RNLE) into a Variable Lifting Index (VLI). Background: There are many jobs that contain individual lifts that vary from lift to lift due to the task requirements. The NIOSH Lifting Equation is not suitable in its present form to analyze variable lifting tasks. Method: In extending the prior work on the VLI, two procedures are presented to allow users to analyze variable lifting tasks. One approach involves the sampling of lifting tasks performed by a worker over a shift and the calculation of the Frequency Independent Lift Index (FILI) for each sampled lift and the aggregation of the FILI values into six categories. The Composite Lift Index (CLI) equation is used with lifting index (LI) category frequency data to calculate the VLI. The second approach employs a detailed systematic collection of lifting task data from production and/or organizational sources. The data are organized into simplified task parameter categories and further aggregated into six FILI categories, which also use the CLI equation to calculate the VLI. Results: The two procedures will allow practitioners to systematically employ the VLI method to a variety of work situations where highly variable lifting tasks are performed. Conclusions: The scientific basis for the VLI procedure is similar to that for the CLI originally presented by NIOSH; however, the VLI method remains to be validated. Application: The VLI method allows an analyst to assess highly variable manual lifting jobs in which the task characteristics vary from lift to lift during a shift. PMID:26646300

  12. Dust particle dynamics in atmospheric dust devils

    NASA Astrophysics Data System (ADS)

    Izvekova, Yulia; Popel, Sergey

    2016-04-01

    Dust particle dynamics is modeled in the Dust Devils (DDs). DD is a strong, well-formed, and relatively long-lived whirlwind, ranging from small (half a meter wide and a few meters tall) to large (more than 100 meters wide and more than 1000 meters tall) in Earth's atmosphere. We develop methods for the description of dust particle charging in DDs, discuss the ionization processes in DDs, and model charged dust particle motion. Our conclusions are consistent with the fact that DD can lift a big amount of dust from the surface of a planet into its atmosphere. On the basis of the model we perform calculations and show that DDs are important mechanism for dust uplift in the atmospheres of Earth and Mars. Influence of DD electric field on dynamics of dust particles is investigated. It is shown that influence of the electric field on dust particles trajectories is significant near the ground. At some altitude (more then a quarter of the height of DD) influence of the electric field on dust particles trajectories is negligible. For the calculation of the dynamics of dust electric field can be approximated by effective dipole located at a half of the height of DD. This work was supported by the Russian Federation Presidential Program for State Support of Young Scientists (project no. MK-6935.2015.2).

  13. Design of a high-lift experiment in water including active flow control

    NASA Astrophysics Data System (ADS)

    Beutel, T.; Sattler, S.; El Sayed, Y.; Schwerter, M.; Zander, M.; Büttgenbach, S.; Leester-Schädel, M.; Radespiel, R.; Sinapius, M.; Wierach, P.

    2014-07-01

    This paper describes the structural design of an active flow-control experiment. The aim of the experiment is to investigate the increase in efficiency of an internally blown Coanda flap using unsteady blowing. The system uses tailor-made microelectromechanical (MEMS) pressure sensors to determine the state of the oncoming flow and an actuated lip to regulate the mass flow and velocity of a stream near a wall over the internally blown flap. Sensors and actuators are integrated into a highly loaded system that is extremely compact. The sensors are connected to a bus system that feeds the data into a real-time control system. The piezoelectric actuators using the d 33 effect at a comparable low voltage of 120 V are integrated into a lip that controls the blowout slot height. The system is designed for closed-loop control that efficiently avoids flow separation on the Coanda flap. The setup is designed for water-tunnel experiments in order to reduce the free-stream velocity and the system’s control frequency by a factor of 10 compared with that in air. This paper outlines the function and verification of the system’s main components and their development.

  14. Lift truck safety review

    SciTech Connect

    Cadwallader, L.C.

    1997-03-01

    This report presents safety information about powered industrial trucks. The basic lift truck, the counterbalanced sit down rider truck, is the primary focus of the report. Lift truck engineering is briefly described, then a hazard analysis is performed on the lift truck. Case histories and accident statistics are also given. Rules and regulations about lift trucks, such as the US Occupational Safety an Health Administration laws and the Underwriter`s Laboratories standards, are discussed. Safety issues with lift trucks are reviewed, and lift truck safety and reliability are discussed. Some quantitative reliability values are given.

  15. Effect-Directed Analysis of Human Peroxisome Proliferator-Activated Nuclear Receptors (PPARγ1) Ligands in Indoor Dust.

    PubMed

    Fang, Mingliang; Webster, Thomas F; Stapleton, Heather M

    2015-08-18

    Agonism of human peroxisome proliferator-activated nuclear receptor gamma (PPARγ1) was recently observed in 15 of 25 samples of indoor dust extracts at environmentally relevant exposure levels. In this study, an effect-directed analysis approach was used to identify the primary contributors of PPARγ1 activity in the dust extracts. Three dust extracts showing significant PPARγ1 activity were fractionated with normal phase high-performance liquid chromatography (NP-HPLC) and each fraction was tested for PPARγ1 activity. Three dust extracts showed a similar PPARγ1 activity distribution in the NP-HPLC fractions. In most active fractions, fatty acids (FAs), including oleic acid, stearic acid, palmitic acid and myristic acid, were the primary chemicals identified using gas-chromatography mass spectrometry (GC-MS). Chemical measurements of the FAs in house dust extracts revealed a positive and significant correlation with the observed PPARγ1 activity. To test the role of FAs in the activity, a mixture of four FAs was prepared in the ratios measured in the dust samples and tested for activity. The activity of this mixture was 30-50% of the activity observed in the dust extracts, suggesting they were contributing to the observed activity, but also suggesting additional unknown compounds are likely still present in the dust extracts. To tentatively identify sources of FAs in the dust samples, FAs were quantified in human/animal hair, dead skin cells, and cooking oil. FAs were abundant in all samples and our data indicate that all of these may be sources to indoor dust.

  16. Using Spitzer Data To Obtain Dust Distribution Arounfd The Active Galactic Nucleus NGC 4051

    NASA Astrophysics Data System (ADS)

    Pereira, Vincent; Burrell, A.; Chavez, O.; Fawcett, E.; Elias, R.; Lugo, T.; Morillo, E.; Purpura, M.; Sorokin, S.; Gorjian, V.; Adkins, J.; Borders, K.; Kelly, S.; Martin, C.; Mendez, B.; Paradis, J.; Pittman, P.; Sepulveda, B.

    2010-01-01

    We have used the Rees'model of Seyfert I galaxies to make detailed calculations of dust distribution as a function of the slope of the spectral intensity versus frequency curve in the infra-red. From these results and our observations of the active galactic nucleus NGC 4051 with the Spitzer Space Telescope Infrared Array Camera (IRAC) we obtain the dust distribution function for this nucleus. We feel that this research project with its underlying physical concepts serves as a good introduction to the physics of Seyfert galaxies for high school students.

  17. Transparent self-cleaning dust shield

    DOEpatents

    Mazumder, Malay K.; Sims, Robert A.; Wilson, James D.

    2005-06-28

    A transparent electromagnetic shield to protect solar panels and the like from dust deposition. The shield is a panel of clear non-conducting (dielectric) material with embedded parallel electrodes. The panel is coated with a semiconducting film. Desirably the electrodes are transparent. The electrodes are connected to a single-phase AC signal or to a multi-phase AC signal that produces a travelling electromagnetic wave. The electromagnetic field produced by the electrodes lifts dust particles away from the shield and repels charged particles. Deposited dust particles are removed when the electrodes are activated, regardless of the resistivity of the dust. Electrostatic charges on the panel are discharged by the semiconducting film. When used in conjunction with photovoltaic cells, the power for the device may be obtained from the cells themselves. For other surfaces, such as windshields, optical windows and the like, the power must be derived from an external source. One embodiment of the invention employs monitoring and detection devices to determine when the level of obscuration of the screen by dust has reached a threshold level requiring activation of the dust removal feature.

  18. Lunar Dust and Lunar Simulant Activation, Monitoring, Solution and Cellular Toxicity Properties

    NASA Technical Reports Server (NTRS)

    Jeevarajan, A.S.; Wallace, W.T.

    2009-01-01

    During the Apollo missions, many undesirable situations were encountered that must be mitigated prior to returning humans to the moon. Lunar dust (that part of the lunar regolith less than 20 m in diameter) was found to produce several problems with astronaut s suits and helmets, mechanical seals and equipment, and could have conceivably produced harmful physiological effects for the astronauts. For instance, the abrasive nature of the dust was found to cause malfunctions of various joints and seals of the spacecraft and suits. Additionally, though efforts were made to exclude lunar dust from the cabin of the lunar module, a significant amount of material nonetheless found its way inside. With the loss of gravity correlated with ascent of the lunar module from the lunar surface to rendezvous with the command module, much of the major portions of the contaminating soil and dust began to float, irritating the astronaut s eyes and being inhaled into their lungs. Our goal has been to understand some of the properties of lunar dust that could lead to possible hazards for humans. Due to the lack of an atmosphere, there is nothing to protect the lunar soil from ultraviolet radiation, solar wind, and meteorite impacts. These processes could all serve to activate the soil, or produce reactive surface species. In order to understand the possible toxic effects of the reactive dust, it is necessary to reactivate the dust, as samples returned during the Apollo missions were exposed to the atmosphere of the Earth. We have used grinding and UV exposure to mimic some of the processes occurring on the Moon. The level of activation has been monitored using two methods: fluorescence spectroscopy and electron paramagnetic resonance spectroscopy (EPR). These techniques allow the monitoring of hydroxyl radical production in solution. We have found that grinding of lunar dust produces 2-3 times the concentration of hydroxyl radicals as lunar simulant and 10 times that of quartz. Exposure

  19. Are All Active Galactic Nuclei Born Equal? The Silicate Dust Mineralogy Perspective

    NASA Astrophysics Data System (ADS)

    Li, Aigen

    Dust is the cornerstone of the unification theory of active galactic nuclei (AGNs). This theory proposes that all AGNs are essentially the same object or "born equal" but viewed from different lines of sight; much of the observed diversity arises from different viewing angles toward the central engine and a dusty toroidal structure around it. When the dusty torus is viewed face-on, both the central engine and the broad-line regions can be seen directly causing objects to appear as type 1 AGNs; when the dusty torus is viewed edge- on, the anisotropic obscuration created by the torus causes objects to appear as type 2 AGNs. It is this crucial role played by dust in the unified model of AGNs that makes understanding dust properties very important in understanding AGNs. Little is known about the dust in the circumnuclear torus of AGNs. There is evidence suggesting that the size and composition of the dust in AGNs may differ substantially from that of the Galactic interstellar dust, as reflected by the flat or "gray" extinction, and the anomalous silicate emission or absorption features observed respectively in type 1 and type 2 AGNs. The silicate feature profiles of AGNs are rather diverse in peak wavelengths, widths, strengths, and band ratios of the 18 micrometer O--Si--O feature to the 9.7 micrometer Si--O feature, suggesting that the AGN silicate grains are diverse in composition and size (or probably not "born equal"). We propose a two-year project to study the size and composition of the dust in AGNs, with special attention paid to the silicate mineralogy. We will obtain constraints on the silicate composition and size by modeling the Spitzer IRS spectra of >100 AGNs of various types. We will examine whether (and how) the silicate composition and size properties vary with the properties of an AGN (e.g. type, luminosity). This research will improve our understanding of the physical properties of the dust torus and the origin of the observed silicate emission

  20. Spirit Feels Dust Gust

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On sol 1149 (March 28, 2007) of its mission, NASA's Mars Exploration Rover Spirit caught a wind gust with its navigation camera. A series of navigation camera images were strung together to create this movie. The front of the gust is observable because it was strong enough to lift up dust. From assessing the trajectory of this gust, the atmospheric science team concludes that it is possible that it passed over the rover. There was, however, no noticeable increase in power associated with this gust. In the past, dust devils and gusts have wiped the solar panels of dust, making it easier for the solar panels to absorb sunlight.

  1. NARROW DUST JETS IN A DIFFUSE GAS COMA: A NATURAL PRODUCT OF SMALL ACTIVE REGIONS ON COMETS

    SciTech Connect

    Combi, M. R.; Tenishev, V. M.; Rubin, M.; Fougere, N.; Gombosi, T. I.

    2012-04-10

    Comets often display narrow dust jets but more diffuse gas comae when their eccentric orbits bring them into the inner solar system and sunlight sublimates the ice on the nucleus. Comets are also understood to have one or more active areas covering only a fraction of the total surface active with sublimating volatile ices. Calculations of the gas and dust distribution from a small active area on a comet's nucleus show that as the gas moves out radially into the vacuum of space it expands tangentially, filling much of the hemisphere centered on the active region. The dust dragged by the gas remains more concentrated over the active area. This explains some puzzling appearances of comets having collimated dust jets but more diffuse gaseous atmospheres. Our test case is 67P/Churyumov-Gerasimenko, the Rosetta mission target comet, whose activity is dominated by a single area covering only 4% of its surface.

  2. Comet 103P/Hartley 2 at perihelion: gas and dust activity

    NASA Astrophysics Data System (ADS)

    Lara, L. M.; Lin, Z.-Y.; Meech, K.

    2011-08-01

    Context. The comet 103P/Hartley 2, target of the EPOXI mission (NASA), was supposed to be observed for 3 days around its perihelion, from October 27 to 29, 2010, but photometric data were obtained only on October 27 and 29, 2010. On both dates, the comet visibility was not optimal due to its proximity to the Moon, as projected on the plane of the sky, whereas on October 28, the comet could not be observed at all. Aims: The goal of the campaign was to give ground support to the EPOXI mission by establishing a baseline of activity at perihelion to be compared with in situ activity observed by the space mission about 7 days later on Nov. 4, 2010. We aimed to assess gas and dust production rates, to study the gas and dust coma morphology, to investigate the behaviour of the refractory component by analysing the dust colour variations with date and with projected cometocentric distance, ρ, and to determine the slope of the surface brightness profiles, B, as a function of ρ. Methods: Long-slit spectra and optical broad- and narrowband images were acquired with the instrument ACAM mounted on the William Herschel Telescope (WHT) at La Palma Observatory. We investigated the evolution of the dust coma morphology from the images acquired with specific continuum cometary filters (in the blue and red wavelength region) with image-enhancing techniques. We studied (1) the gas and dust production rates; (2) the dust radial brightness profiles; (3) the profiles of the CN, C2, C3 and NH2 column densities, and (4) the CN and C3 coma morphologies. The dust and gas profiles were azimuthally averaged, as well as measured in both the E-W direction (~Sun-antisolar direction) and in a direction defined by the slit orientation at PA 70 to 250 degrees. Results: The morphological analysis of the dust coma reveals only one structure. Aside from the dust tail in the west direction, a bright jet is detected in images acquired on October 27 at 03:00-04:00 UT. This jet turns on and off and it is

  3. Observations of the initiation and evolution of the 2001 Mars global dust storm

    NASA Astrophysics Data System (ADS)

    Strausberg, Melissa J.; Wang, Huiqun; Richardson, Mark I.; Ewald, Shawn P.; Toigo, Anthony D.

    2005-02-01

    A global dust storm occurred on Mars between June and October 2001. The storm began near Hellas just before southern spring equinox (~Ls = 177°). Local storms, likely forced by a combination of slope-flow and ice cap thermal contrasts, were observed to propagate along the northwestern rim of Hellas, apparently triggering the global storm. Cap-edge storm activity for much of late southern winter was similar in 2001 to one Mars year earlier; however, a very large storm propagated into the basin just after Ls = 177°. Subsequently, the total area of storm activity in 2001 was roughly double that of the previous year. For about 10 days, dust lifting was limited to the Hellas region. As additional storms propagated into Hellas, activity built and extended northward into Syrtis and eastward into Hesperia. It is not clear whether transport or spreading of lifting were of greatest importance for expansion. At Ls = 185° the storm began to spread rapidly to the east, along a line from the southern pole to the northern tropics. Essentially no storm propagation to the west occurred, yielding strong zonal asymmetry of expansion. As the dust storm reached the western edge of Tharsis, secondary dust lifting centers developed in Daedalia and Solis (southeastern Tharsis). Subsequently, the storm rapidly encompassed the planet (by Ls = 193°). Once fully global, the Syria/Solis/Daedalia lifting center appeared to dominate (on the basis of cloud top morphology), with Hellas quiescent. By Ls = 212°, lifting could no longer be discerned. Thereafter, dust haze appeared uniform and diffuse, and decay appeared to have set in.

  4. 30526 artificial lift

    SciTech Connect

    Not Available

    1989-01-01

    This book focuses on the four major methods of artificial lift: sucker-rod pumping, gas lift, electrical submersible pumping (ESP) and hydraulic pumping. Though more than 80% of artificially lifted wells worldwide are rod-pumped, the large majority of these wells are low-volume, stripper-type producers. For this reason, sucker-rod pumping papers comprise less than 40% of the 26 SPE papers selected.

  5. Lifting BLS Power Supplies

    SciTech Connect

    Sarychev, Michael

    2007-08-01

    This note describes BLS power supplies lifting techniques and provides stress calculations for lifting plate and handles bolts. BLS power supply weight is about 120 Lbs, with the center of gravity shifted toward the right front side. A lifting plate is used to attach a power supply to a crane or a hoist. Stress calculations show that safety factors for lifting plate are 12.9 (vs. 5 required) for ultimate stress and 5.7 (vs. 3 required) for yield stress. Safety factor for shackle bolt thread shear load is 37, and safety factor for bolts that attach handles is 12.8.

  6. The effect of local exhaust ventilation controls on dust exposures during concrete cutting and grinding activities.

    PubMed

    Croteau, Gerry A; Guffey, Steven E; Flanagan, Mary Ellen; Seixas, Noah S

    2002-01-01

    This study assessed the effectiveness of commercially available local exhaust ventilation (LEV) systems for controlling respirable dust and crystalline silica exposures during concrete cutting and grinding activities. Work activities were performed by union-sponsored apprentices and included tuck-point grinding, surface grinding, paver block and brick cutting (masonry saw), and concrete block cutting (hand-held saw). In a randomized block design, implemented under controlled field conditions, three ventilation rates (0, 30, and 75 cfm) were tested for each tool. Each ventilation treatment was replicated three times in random order for a total of nine 15-min work sessions per study subject. With the exception of the hand-held saw, the use of LEV resulted in a significant (p < 0.05) reduction in respirable dust exposure. Mean exposure levels for the 75 cfm treatments were less than that of the 30 cfm treatments; however, differences between these two treatments were only significant for paver block cutting (p < 0.01). Although exposure reduction was significant (70-90% at the low ventilation rate and 80-95% reduction at the high ventilation rate), personal respirable dust [corrected] exposures remained very high: 1.4-2.8 x PEL (permissible exposure limit) at the low ventilation rate and 0.9-1.7 x PEL at the high ventilation rate. Exposure levels found under actual field conditions would likely be lower due to the intermittent nature of most job tasks. Despite incomplete control LEV has merit, as it would reduce the risk of workers developing disease, allow workers to use a lower level of respiratory protection, protect workers during short duration work episodes reduce exposure to nearby workers, and reduce clean-up associated dust exposures.

  7. Spatio-temporal distribution of Saharan dust source activations inferred from 15-minute MSG-SEVIRI observations and its links to meteorological processes (Invited)

    NASA Astrophysics Data System (ADS)

    Schepanski, K.; Tegen, I.

    2009-12-01

    Mineral dust aerosol emitted from arid and semi-arid areas impacts on the weather and climate system by affecting e.g. radiation fluxes and nutrient cycles. The emission of dust particles depend strongly on surface wind velocity and turbulent fluxes as well as on surface characteristics like surface texture and vegetation cover. To estimate the effect of dust aerosol, detailed knowledge on the spatio-temporal distribution of active dust sources is necessary. As dust sources are mostly located over remote areas satellite observations are suitable for localizing active dust sources. Thereby the accuracy of determining dust sources from such an indirect method is limited by the temporal resolution and the ambiguities of the retrieval. A 1°x1° map on the spatial and temporal (3-hourly) distribution of dust source activations (DSA) over North Africa is compiled starting in March 2006. For dust source identification 15-minute Meteosat Second Generation (MSG) infra-red (IR) dust index images are used based on brightness temperature measurements by the Spinning enhanced Visible and Infra-Red Imager (SEVIRI) at 8.7 µm, 10.8 µm and 12.0 µm. This data set has been used (1) to identify most active dust source areas, and (2) to investigate on the temporal distribution of occurring dust source activations. Over the Sahara Desert 65% of dust sources becomes active during 06-09 UTC pointing towards an important role of the break-down of the nocturnal low-level jet (LLJ) for dust mobilization besides other meteorological features like density currents, haboobs, and cyclones. Furthermore the role of the nocturnal LLJ for dust mobilization over the Sahara is investigated by weather observations and a modelling study. DSA observations of the last 3.5 years indicate an interannual variability in frequencies of local dust source activations. The causes of this variability will be analyzed with respect to corresponding atmospheric conditions.

  8. Thermophoresis and dust devils on the planet Mars.

    PubMed

    Gheynani, Babak T; Emami-Razavi, Mohsen; Taylor, Peter A

    2011-11-01

    In the Martian atmosphere dust is abundant and is continuously replenished by the entrainment of materials and sediments from the surface of the planet. The sediment concentrations are particularly high and noticeable in whirlwinds, also known as dust devils. Assuming the thermophoresis force as the main driver of dust particles lifting from the surface, the dust process of the Martian atmosphere and its naturally formed dust devils are investigated for the northern polar region of the planet. Our simulated convective boundary layer shows that it may be unlikely that visible dust devils are formed only due to thermophoresis effects and some other lifting mechanisms are required.

  9. View south; detail of top of lift span and lifting ...

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

    View south; detail of top of lift span and lifting cables. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Lift Bridge, Mouth of Reserve Basin, League Island, Philadelphia, Philadelphia County, PA

  10. Activation of Human Peroxisome Proliferator-Activated Nuclear Receptors (PPARγ1) by Semi-Volatile Compounds (SVOCs) and Chemical Mixtures in Indoor Dust.

    PubMed

    Fang, Mingliang; Webster, Thomas F; Stapleton, Heather M

    2015-08-18

    Recently, we reported that several semi-volatile compounds (SVOCs) were competitive ligands for human peroxisome proliferator-activated nuclear receptor gamma (PPARγ1). We also observed significant binding from chemicals extracted from house dust at a concentration of 3 mg dust/mL in the dosing medium. To follow up on this study, a commercially available reporter gene assay (GeneBLAzer PPARγ1 non-DA Assay, Invitrogen) was used to investigate the PPARγ1 activation by 30 common SVOCs (e.g., brominated flame retardants, organophosphates, and phthalates) and in house dust extracts. Twenty-eight SVOCs or their metabolites were either confirmed or for the first time were found to be weak or moderate PPARγ1 agonists. We also observed activation in 15 of 25 dust extracts examined. In some cases, activation was as high as 50% of the activation of the positive control (rosiglitazone). Furthermore, there was a significant and positive correlation (r = 0.7, p < 0.003) between data collected from this reporter assay and our previous ligand binding assay tested on the same dust extracts. Our results suggest that many SVOCs ubiquitous in house dust, or their metabolites, are possible PPARγ1 agonists. Also, chemical mixtures present in house dust at environmentally relevant levels can activate human PPARγ1 in a transfected cell culture system, and further research is needed to identify the primary chemical(s) driving this activity. PMID:26172262

  11. The location of the dust causing internal reddening of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Heard, Clio Z. P.; Gaskell, C. Martin

    2016-10-01

    We use the Balmer decrements of the broad-line regions (BLRs) and narrow-line regions (NLRs) of active galactic nuclei (AGNs) as reddening indicators to investigate the location of the dust for four samples of AGNs with reliable estimates of the NLR contribution to the Balmer lines. Intercomparison of the NLR and BLR Balmer decrements indicates that the reddening of the NLR sets a lower limit to the reddening of the BLR. Almost no objects have high NLR reddening but low BLR reddening. The reddening of the BLR is often substantially greater than the reddening of the NLR. The BLR reddening is correlated with the equivalent widths of [O III] lines and the intensity of the [O III] lines relative to broad Hβ. We find these relationships to be consistent with the predictions of a simple model where the additional dust reddening the BLR is interior to the NLR. We thus conclude that the dust causing the additional reddening of the accretion disc and BLR is mostly located at a smaller radius than the NLR.

  12. Portable Lifting Seat

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce

    1993-01-01

    Portable lifting machine assists user in rising from seated position to standing position, or in sitting down. Small and light enough to be carried like briefcase. Used on variety of chairs and benches. Upholstered aluminum box houses mechanism of lifting seat. Springs on outer shaft-and-arm subassembly counterbalance part of user's weight to assist motor.

  13. Catwalk grate lifting tool

    DOEpatents

    Gunter, L.W.

    1992-08-11

    A device is described for lifting catwalk grates comprising an elongated bent member with a handle at one end and a pair of notched braces and a hook at the opposite end that act in conjunction with each other to lock onto the grate and give mechanical advantage in lifting the grate. 10 figs.

  14. Portable seat lift

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce (Inventor)

    1994-01-01

    A portable seat lift that can help individuals either (1) lower themselves to a sitting position or (2) raise themselves to a standing position is presented. The portable seat lift consists of a seat mounted on a base with two levers, which are powered by a drive unit.

  15. Understanding Wing Lift

    ERIC Educational Resources Information Center

    Silva, J.; Soares, A. A.

    2010-01-01

    The conventional explanation of aerodynamic lift based on Bernoulli's equation is one of the most common mistakes in presentations to school students and is found in children's science books. The fallacies in this explanation together with an alternative explanation for aerofoil lift have already been presented in an excellent article by Babinsky…

  16. High lift aerodynamics

    NASA Technical Reports Server (NTRS)

    Sullivan, John; Schneider, Steve; Campbell, Bryan; Bucci, Greg; Boone, Rod; Torgerson, Shad; Erausquin, Rick; Knauer, Chad

    1994-01-01

    The current program is aimed at providing a physical picture of the flow physics and quantitative turbulence data of the interaction of a high Reynolds number wake with a flap element. The impact of high lift on aircraft performance is studied for a 150 passenger transport aircraft with the goal of designing optimum high lift systems with minimum complexity.

  17. Risk of miscarriage and occupational activity: a systematic review and meta-analysis regarding shift work, working hours, lifting, standing and physical workload

    PubMed Central

    Bonde, Jens Peter E; Jørgensen, Kristian Tore; Bonzini, Matteo; Palmer, Keith T

    2013-01-01

    Objective Previous studies have indicated that shift work, long working hours and prevalent workplace exposures such as lifting, standing and physical workload increase the risk of miscarriage, but the evidence is conflicting. We conducted a systematic review of original research reports. Methods A search in Medline and EMBASE 1966 - 2012 identified 30 primary papers reporting the relative risk (RR) of miscarriage according to one or more of the five occupational activities of interest. Following an assessment of completeness of reporting, confounding and bias, each risk estimate was characterised as more or less likely to be biased. Studies with equivalent measures of exposure were pooled to obtain a weighted common risk estimate. Sensitivity analyses excluded studies most likely to be biased. Results Working fixed nights was associated with a moderately increased risk of miscarriage [pooled RR 1.51 (95% CI 1.27-1.78, n=5], while working in 3-shift schedules, working for >40 hours weekly, lifting>100 kg/day, standing > 6 hours/day and physical workload were associated with small risk increments, with the pooled RRs ranging from 1.12 (three shift schedule, n=7) to 1.36 (working hours, n=10). RRs for working hours and standing became smaller when analyses were restricted to higher quality studies. Conclusion These largely reassuring findings do not provide a strong case for mandatory restrictions in relation to shift work, long working hours, occupational lifting, standing and physical workload. Considering the limited evidence base, however, it may be prudent to advise women against work entailing high levels of these exposures and women with at-risk pregnancies should receive tailored individual counselling PMID:23235838

  18. Identical full-scale biogas-lift reactors (Blrs) with anaerobic granular sludge and residual activated sludge for brewery wastewater treatment and kinetic modeling.

    PubMed

    Xu, Fu; Huang, Zhenxing; Miao, Hengfeng; Ren, Hongyan; Zhao, Mingxing; Ruan, Wenquan

    2013-10-01

    Two identical full-scale biogas-lift reactors treating brewery wastewater were inoculated with different types of sludge to compare their operational conditions, sludge characteristics, and kinetic models at a mesophilic temperature. One reactor (R1) started up with anaerobic granular sludge in 12 weeks and obtained a continuously average organic loading rate (OLR) of 7.4 kg chemical oxygen demand (COD)/(m3 x day), COD removal efficiency of 80%, and effluent COD of 450 mg/L. The other reactor (R2) started up with residual activated sludge in 30 weeks and granulation accomplished when the reactor reached an average OLR of 8.3 kg COD/(m3 x day), COD removal efficiency of 90%, and effluent COD of 240 mg/L. Differences in sludge characteristics, biogas compositions, and biogas-lift processes may be accounted for the superior efficiency of the treatment performance of R2 over R1. Grau second-order and modified StoverKincannon models based on influent and effluent concentrations as well as hydraulic retention time were successfully used to develop kinetic parameters of the experimental data with high correlation coefficients (R2 > 0.95), which further showed that R2 had higher treatment performance than R1. These results demonstrated that residual activated sludge could be used effectively instead of anaerobic granular sludge despite the need for a longer time.

  19. The "wind of 120 days" and dust storm activity over the Sistan Basin

    NASA Astrophysics Data System (ADS)

    Alizadeh-Choobari, O.; Zawar-Reza, P.; Sturman, A.

    2014-06-01

    Mesoscale features play a critical role in creating the strong "wind of 120 days" common in eastern Iran and western Afghanistan. The Weather Research and Forecasting with Chemistry (WRF/Chem) model is used with the available observations to investigate the "wind of 120 days", dust storm activity over the Sistan Basin, and major sources of dust influencing Iran. The winds are strong from mid-May to mid-September when a persistent high-pressure system over the high mountains of the Hindu Kush in northern Afghanistan, combined with a summertime thermal low over desert lands of eastern Iran and western Afghanistan, produce a strong pressure gradient. The winds become accelerated by the channeling effect of the surrounding orography. A northerly low level jet (LLJ) along the Iran-Afghanistan border has a peak at 300-500 m and is strongest in July with the nighttime monthly averaged wind speed of 20 m s- 1, and extends across a broad latitudinal area along the Iran-Afghanistan border. The strong near-surface wind speed along with the LLJ results in substantial dust emission from the Sistan Basin and subsequent long-range meridional transport. Dried Hamoun Lake in the Sistan Basin contains large amounts of erodible sediment that is required for dust entrainment. The LLJ is persistent throughout the night, but is weakened during the day. A pronounced diurnal cycle in the near-surface wind speed has been identified with a peak in the mid-morning in association with momentum transfer from the jet level down to the surface as the daytime mixed layer evolves.

  20. Spirit Captures Two Dust Devils On the Move

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1 Annotated

    At the Gusev site recently, skies have been very dusty, and on its 421st sol (March 10, 2005) NASA's Mars Exploration Rover Spirit spied two dust devils in action. This is an image from the rover's navigation camera.

    Views of the Gusev landing region from orbit show many dark streaks across the landscape -- tracks where dust devils have removed surface dust to show relatively darker soil below -- but this is the first time Spirit has photographed an active dust devil.

    Scientists are considering several causes of these small phenomena. Dust devils often occur when the Sun heats the surface of Mars. Warmed soil and rocks heat the layer of atmosphere closest to the surface, and the warm air rises in a whirling motion, stirring dust up from the surface like a miniature tornado. Another possibility is that a flow structure might develop over craters as wind speeds increase. As winds pick up, turbulence eddies and rotating columns of air form. As these columns grow in diameter they become taller and gain rotational speed. Eventually they become self-sustaining and the wind blows them down range.

    One sol before this image was taken, power output from Spirit's solar panels went up by about 50 percent when the amount of dust on the panels decreased. Was this a coincidence, or did a helpful dust devil pass over Spirit and lift off some of the dust?

    By comparing the separate images from the rover's different cameras, team members estimate that the dust devils moved about 500 meters (1,640 feet) in the 155 seconds between the navigation camera and hazard-avoidance camera frames; that equates to about 3 meters per second (7 miles per hour). The dust devils appear to be about 1,100 meters (almost three-quarters of a mile) from the rover.

  1. Interior of lift mechanism area of eastern lift span, looking ...

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

    Interior of lift mechanism area of eastern lift span, looking northwest. - Arlington Memorial Bridge, Spanning Potomac River between Lincoln Memorial & Arlington National Cemetery, Washington, District of Columbia, DC

  2. The effect of clay particles on the activity of suspended autotrophic nitrifying bacteria and on the performance of an air-lift reactor.

    PubMed

    Vieira, M J; Pacheco, A P; Pinho, I A; Melo, L F

    2001-02-01

    Clay minerals have some properties, namely a high surface area and the ability of ion exchange that may exert some effects on microbial systems. It is often difficult to know the way the clay is exerting its influence and whether its presence improves a given metabolic process. The present work concerns the study of the effect of the addition of powdered kaolin to autotrophic nitrification systems, and includes the study of the effects of the particles on the activity of a suspended nitrifying bacteria consortium and on the performance of an air-lift biofilm reactor used for tertiary nitrification. Concerning the suspended culture, kaolin particles produced stimulation on the specific endogenous and exogenous respiration rates of the bacteria, probably due to a nutritional effect supplied by the clay. This effect was more pronounced for the ammonia oxidation rates, although nitrite oxidation was also enhanced but to a lesser extent. In respect to the presence of kaolin particles in the air-lift reactor, the results obtained indicate that the clay particles become incorporated in the biofilm pellets, but do not change significantly their thickness or their shape. However, nitrate production decreased when the concentration of particles increased. The low adsorption of ammonia by the kaolin indicated that the clay particles embedded in the biofilm did not probably retain the ions. Although it was not proved, precipitation of salts may have occurred.

  3. Postural control during lifting.

    PubMed

    Kollmitzer, Josef; Oddsson, L; Ebenbichler, G R; Giphart, J E; DeLuca, C J

    2002-05-01

    Any voluntary motion of the body causes an internal perturbation of balance. Load transfer during manual material handling may increase these perturbations. This study investigates effects of stance condition on postural control during lifting. Nineteen healthy subjects repeatedly lifted and lowered a load between a desk and a shelf. The base of support was varied between parallel and step stance. Ground reaction force and segmental kinematics were measured. Load transfer during lifting perturbed balance. In parallel stance postural response consisted of axial movements in the sagittal plane. Such strategy was accompanied by increased posterior shear forces after lift-off. Lifting in step stance provided extended support in anterior/posterior direction. The postural control mechanisms in the sagittal plane are less complex as compared to parallel stance. However, lifting in step stance was asymmetrical and thus accompanied by distinct lateral transfer of the body. Lateral shear forces were larger as compared to parallel stance. Both lifting techniques exhibit positive and negative aspects. We cannot recommend either one as being better in terms of postural control.

  4. PERSPECTIVE: Dust, fertilization and sources

    NASA Astrophysics Data System (ADS)

    Remer, Lorraine A.

    2006-11-01

    Aerosols, tiny suspended particles in the atmosphere, play an important role in modifying the Earth's energy balance and are essential for the formation of cloud droplets. Suspended dust particles lifted from the world's arid regions by strong winds contain essential minerals that can be transported great distances and deposited into the ocean or on other continents where productivity is limited by lack of usable minerals [1]. Dust can transport pathogens as well as minerals great distance, contributing to the spread of human and agricultural diseases, and a portion of dust can be attributed to human activity suggesting that dust radiative effects should be included in estimates of anthropogenic climate forcing. The greenish and brownish tints in figure 1 show the wide extent of monthly mean mineral dust transport, as viewed by the MODerate resolution Imaging Spectroradiometer (MODIS) satellite sensor. The monthly mean global aerosol system for February 2006 from the MODIS aboard the Terra satellite Figure 1. The monthly mean global aerosol system for February 2006 from the MODIS aboard the Terra satellite. The brighter the color, the greater the aerosol loading. Red and reddish tints indicate aerosol dominated by small particles created primarily from combustion processes. Green and brownish tints indicate larger particles created from wind-driven processes, usually transported desert dust. Note the bright green band at the southern edge of the Saharan desert, the reddish band it must cross if transported to the southwest and the long brownish transport path as it crosses the Atlantic to South America. Image courtesy of the NASA Earth Observatory (http://earthobservatory.nasa.gov). Even though qualitatively we recognize the extent and importance of dust transport and the role that it plays in fertilizing nutrient-limited regions, there is much that is still unknown. We are just now beginning to quantify the amount of dust that exits one continental region and the

  5. Measurements of Martian dust devil winds with HiRISE

    USGS Publications Warehouse

    Choi, D.S.; Dundas, C.M.

    2011-01-01

    We report wind measurements within Martian dust devils observed in plan view from the High Resolution Imaging Science Experiment (HiRISE) orbiting Mars. The central color swath of the HiRISE instrument has three separate charge-coupled devices (CCDs) and color filters that observe the surface in rapid cadence. Active features, such as dust devils, appear in motion when observed by this region of the instrument. Our image animations reveal clear circulatory motion within dust devils that is separate from their translational motion across the Martian surface. Both manual and automated tracking of dust devil clouds reveal tangential winds that approach 20-30 m s -1 in some cases. These winds are sufficient to induce a ???1% decrease in atmospheric pressure within the dust devil core relative to ambient, facilitating dust lifting by reducing the threshold wind speed for particle elevation. Finally, radial velocity profiles constructed from our automated measurements test the Rankine vortex model for dust devil structure. Our profiles successfully reveal the solid body rotation component in the interior, but fail to conclusively illuminate the profile in the outer regions of the vortex. One profile provides evidence for a velocity decrease as a function of r -1/2, instead of r -1, suggestive of surface friction effects. However, other profiles do not support this observation, or do not contain enough measurements to produce meaningful insights. Copyright 2011 by the American Geophysical Union.

  6. Metal Ion Removal from Wastewaters by Sorption on Activated Carbon, Cement Kiln Dust, and Sawdust.

    PubMed

    Shaheen, Sabry M; Eissa, Fawzy I; Ghanem, Khaled M; El-Din, Hala M Gamal; Al Anany, Fathia S

    2015-06-01

    This study assessed the efficiency of activated carbon, cement kiln dust (CKD), and sawdust for the removal of cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) from aqueous solutions under mono-metal and competitive sorption systems and the removal of Cd, Cu, and Zn from different industrial wastewaters. Batch equilibrium experiments were conducted in a mono-metal and competitive sorption system. The efficiency of the sorbents in the removal of Cd, Cu, and Zn from industrial wastewaters was also investigated. Cement kiln dust expressed the highest affinity for the metals followed by activated carbon and sawdust. Competition among the metals changed their distribution coefficient (Kd) with the sorbents. Sorption of Pb and Cu was higher than Cd and Zn. The average metal removal from the wastewaters varied from 74, 61, and 60% for Cd, Cu, and Zn, respectively, to nearly 100%. The efficiencies of CKD and activated carbon in removing metals were higher than sawdust, suggesting their potential as low-cost sorbents for the removal of toxic metals from wastewaters.

  7. Metal Ion Removal from Wastewaters by Sorption on Activated Carbon, Cement Kiln Dust, and Sawdust.

    PubMed

    Shaheen, Sabry M; Eissa, Fawzy I; Ghanem, Khaled M; El-Din, Hala M Gamal; Al Anany, Fathia S

    2015-06-01

    This study assessed the efficiency of activated carbon, cement kiln dust (CKD), and sawdust for the removal of cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) from aqueous solutions under mono-metal and competitive sorption systems and the removal of Cd, Cu, and Zn from different industrial wastewaters. Batch equilibrium experiments were conducted in a mono-metal and competitive sorption system. The efficiency of the sorbents in the removal of Cd, Cu, and Zn from industrial wastewaters was also investigated. Cement kiln dust expressed the highest affinity for the metals followed by activated carbon and sawdust. Competition among the metals changed their distribution coefficient (Kd) with the sorbents. Sorption of Pb and Cu was higher than Cd and Zn. The average metal removal from the wastewaters varied from 74, 61, and 60% for Cd, Cu, and Zn, respectively, to nearly 100%. The efficiencies of CKD and activated carbon in removing metals were higher than sawdust, suggesting their potential as low-cost sorbents for the removal of toxic metals from wastewaters. PMID:26459819

  8. A new look at Apollo 17 LEAM data: Nighttime dust activity in 1976

    NASA Astrophysics Data System (ADS)

    Grün, Eberhard; Horányi, Mihály

    2013-12-01

    75% of the periods when LEAM was switched on in 1976. We did not find a systematic correlation between the infrequent heater switches and the occurrence of signals. During the lunar night the temperature was quite stable at approx. -25 °C. One TOF dust impact event and 19 potential dust events were recorded by all three sensors during the periods when the instrument was at moderate temperatures. This corresponds to an average event rate of 0.25/day. While nine events are compatible with a random occurrence the other 10 events occurred in three statistically significant bursts within about 1 h or less after another. Two bursts occurred within the middle of lunar night and one burst of three events was recorded by the West sensor just an hour before sunrise. The background rates are compatible with impact rates recorded by the dust instruments onboard the Pioneer 8 and 9 spacecraft in interplanetary space. Based on our definition of sunrise and sunset, the 1976 LEAM data do not indicate strongly enhanced dust activity at the terminator.

  9. Characterization of dust activity from Martian Year (MY) 27 to MY 32 observed by the Planetary Fourier Spectrometer aboard the Mars Express spacecraft

    NASA Astrophysics Data System (ADS)

    Wolkenberg, Paulina; Giuranna, Marco; Aoki, Shohei; Scaccabarozzi, Diego; Saggin, Bortolino; Formisano, Vittorio

    2016-04-01

    More than 2,500,000 spectra have been collected by the Planetary Fourier Spectrometer aboard Mars Express spacecraft after 12 years of activity. The data span more than six Martian years, from MY26, Ls = 331°, to MY 33, Ls = 78°. This huge dataset has been used to build a new database of atmospheric parameters, including atmospheric and surface temperatures, and dust and water ice opacity. Dust aerosols suspended in the atmosphere affect its thermal structure and are a major driver of the circulation. They are always present in the Martian atmosphere, but the amount varies greatly depending on location and season. We analyze dust opacities at 1075 cm-1 retrieved from the PFS long-wavelength channel spectra to characterize the dust activity on Mars for the relevant period. The dust storm season (Ls= 185° - 310°) is monitored for each Martian year. All dust observations show a seasonal pattern, which is ruled by the occurrence of regional and/or global dust storms. Regional dust storms are observed every year, while a planet encircling dust storm occurred in MY 28, when the highest values of dust opacity are also observed (~ 2.45). We characterize the spatial and temporal evolution of these regional and global dust events and investigate the effect of dust on surface and atmospheric temperatures.

  10. Utilizing an Extraterrestrial Analogue to Predict Sediment Migration on Frenchman Flat due to Convective Vortex (Dust Devil) Activity

    NASA Astrophysics Data System (ADS)

    McGee, B. W.

    2006-12-01

    data from the NTS, and combining them with measurements of sediment loading and erosive strength in terrestrial dust devils, it is possible to both illustrate the potential significance of dust devils to currently-accepted radionuclide residence time on Frenchman Flat playa, as well as predict areas of unexpected radionuclide migration and/or attenuation due to dust devil activity.

  11. Ice nucleation properties of mineral dust particles: Determination of onset RHi, IN active fraction, nucleation time-lag, and the effect of active sites on contact angles

    SciTech Connect

    Kulkarni, Gourihar R.; Dobbie, Steven

    2010-01-08

    A newly developed ice nucleation experimental set up was used to investigate the heterogeneous ice nucleation properties of three Saharan and one Spanish dust particle samples. It is observed that the spread in the onset relative humidities with respect to ice (RHi) for Saharan dust particles varies from 104% to 110%, whereas for the Spanish dust from 106% to 110%. The elemental composition analysis shows a prominent Ca feature in the Spanish dust sample which could potentially explain the differences in nucleation threshold. Although spread in the onset RHi for Saharan dust samples were in agreement, their active fractions and nucleation time-lags calculated at various temperature and RHi conditions, for two Saharan dust samples, were not found to be in complete agreement. This could be because of the subtle variation in the elemental composition of the dust samples, and the surface irregularities like steps, cracks, cavities etc. A combination of classical nucleation theory and active site theory is used to understand the importance of these surface irregularities, expressed in terms of active sites, on the nucleability parameter (contact angle) that is widely used in the ice cloud modeling studies. These calculations show that the surface irregularities reduce the contact angle by approximately 10 degrees.

  12. FREIGHT CONTAINER LIFTING STANDARD

    SciTech Connect

    POWERS DJ; SCOTT MA; MACKEY TC

    2010-01-13

    This standard details the correct methods of lifting and handling Series 1 freight containers following ISO-3874 and ISO-1496. The changes within RPP-40736 will allow better reading comprehension, as well as correcting editorial errors.

  13. Advanced underwater lift device

    NASA Technical Reports Server (NTRS)

    Flanagan, David T.; Hopkins, Robert C.

    1993-01-01

    Flexible underwater lift devices ('lift bags') are used in underwater operations to provide buoyancy to submerged objects. Commercially available designs are heavy, bulky, and awkward to handle, and thus are limited in size and useful lifting capacity. An underwater lift device having less than 20 percent of the bulk and less than 10 percent of the weight of commercially available models was developed. The design features a dual membrane envelope, a nearly homogeneous envelope membrane stress distribution, and a minimum surface-to-volume ratio. A proof-of-concept model of 50 kg capacity was built and tested. Originally designed to provide buoyancy to mock-ups submerged in NASA's weightlessness simulators, the device may have application to water-landed spacecraft which must deploy flotation upon impact, and where launch weight and volume penalties are significant. The device may also be useful for the automated recovery of ocean floor probes or in marine salvage applications.

  14. Wind tower service lift

    DOEpatents

    Oliphant, David; Quilter, Jared; Andersen, Todd; Conroy, Thomas

    2011-09-13

    An apparatus used for maintaining a wind tower structure wherein the wind tower structure may have a plurality of legs and may be configured to support a wind turbine above the ground in a better position to interface with winds. The lift structure may be configured for carrying objects and have a guide system and drive system for mechanically communicating with a primary cable, rail or other first elongate member attached to the wind tower structure. The drive system and guide system may transmit forces that move the lift relative to the cable and thereby relative to the wind tower structure. A control interface may be included for controlling the amount and direction of the power into the guide system and drive system thereby causing the guide system and drive system to move the lift relative to said first elongate member such that said lift moves relative to said wind tower structure.

  15. Aerodynamic Lifting Force.

    ERIC Educational Resources Information Center

    Weltner, Klaus

    1990-01-01

    Describes some experiments showing both qualitatively and quantitatively that aerodynamic lift is a reaction force. Demonstrates reaction forces caused by the acceleration of an airstream and the deflection of an airstream. Provides pictures of demonstration apparatus and mathematical expressions. (YP)

  16. Carbon in intimate contact with quartz reduces the biological activity of crystalline silica dusts.

    PubMed

    Ghiazza, Mara; Tomatis, Maura; Doublier, Sophie; Grendene, Francesca; Gazzano, Elena; Ghigo, Dario; Fubini, Bice

    2013-01-18

    To evaluate the effect of carbonaceous materials on the pathogenic activity of quartz dusts, mixtures of carbon soot (1 and 10%) and quartz (Min-U-Sil) were prepared and then milled so to attain an intimate association of carbon and the quartz surface. Both cellular and cell-free tests show that carbon associated to quartz completely inhibits the typical free radical generation of quartz dusts (through Fenton activity and homolytic cleavage of a C-H bond) and suppresses the oxidative stress and inflammation induced by quartz alone on MH-S murine macrophage cells (lipid peroxidation, nitric oxide release, and tumor necrosis factor-α synthesis). The cytotoxic response to quartz is also largely reduced. An extremely pure quartz milled with 10% of soot showed inactivating effects on the adverse reactions to quartz similar to Min-U-Sil quartz. None of these effects takes place when the same experiments are carried out with mechanically mixed samples, which suggests that carbon acts not just as a radical quencher but because of its association to the quartz surface.

  17. Theory of lifting surfaces

    NASA Technical Reports Server (NTRS)

    Prandtl , L

    1920-01-01

    The general basis of the theory of lifting surfaces is discussed. The problem of the flow of a fluid about a lifting surface of infinite span is examined in terms of the existence of vortexes in the current. A general theory of permanent flow is discussed. Formulas for determining the influence of aspect ratio that may be applied to all wings, whatever their plane form, are given.

  18. GPU-BASED MONTE CARLO DUST RADIATIVE TRANSFER SCHEME APPLIED TO ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Heymann, Frank; Siebenmorgen, Ralf

    2012-05-20

    A three-dimensional parallel Monte Carlo (MC) dust radiative transfer code is presented. To overcome the huge computing-time requirements of MC treatments, the computational power of vectorized hardware is used, utilizing either multi-core computer power or graphics processing units. The approach is a self-consistent way to solve the radiative transfer equation in arbitrary dust configurations. The code calculates the equilibrium temperatures of two populations of large grains and stochastic heated polycyclic aromatic hydrocarbons. Anisotropic scattering is treated applying the Heney-Greenstein phase function. The spectral energy distribution (SED) of the object is derived at low spatial resolution by a photon counting procedure and at high spatial resolution by a vectorized ray tracer. The latter allows computation of high signal-to-noise images of the objects at any frequencies and arbitrary viewing angles. We test the robustness of our approach against other radiative transfer codes. The SED and dust temperatures of one- and two-dimensional benchmarks are reproduced at high precision. The parallelization capability of various MC algorithms is analyzed and included in our treatment. We utilize the Lucy algorithm for the optical thin case where the Poisson noise is high, the iteration-free Bjorkman and Wood method to reduce the calculation time, and the Fleck and Canfield diffusion approximation for extreme optical thick cells. The code is applied to model the appearance of active galactic nuclei (AGNs) at optical and infrared wavelengths. The AGN torus is clumpy and includes fluffy composite grains of various sizes made up of silicates and carbon. The dependence of the SED on the number of clumps in the torus and the viewing angle is studied. The appearance of the 10 {mu}m silicate features in absorption or emission is discussed. The SED of the radio-loud quasar 3C 249.1 is fit by the AGN model and a cirrus component to account for the far-infrared emission.

  19. GPU-based Monte Carlo Dust Radiative Transfer Scheme Applied to Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Heymann, Frank; Siebenmorgen, Ralf

    2012-05-01

    A three-dimensional parallel Monte Carlo (MC) dust radiative transfer code is presented. To overcome the huge computing-time requirements of MC treatments, the computational power of vectorized hardware is used, utilizing either multi-core computer power or graphics processing units. The approach is a self-consistent way to solve the radiative transfer equation in arbitrary dust configurations. The code calculates the equilibrium temperatures of two populations of large grains and stochastic heated polycyclic aromatic hydrocarbons. Anisotropic scattering is treated applying the Heney-Greenstein phase function. The spectral energy distribution (SED) of the object is derived at low spatial resolution by a photon counting procedure and at high spatial resolution by a vectorized ray tracer. The latter allows computation of high signal-to-noise images of the objects at any frequencies and arbitrary viewing angles. We test the robustness of our approach against other radiative transfer codes. The SED and dust temperatures of one- and two-dimensional benchmarks are reproduced at high precision. The parallelization capability of various MC algorithms is analyzed and included in our treatment. We utilize the Lucy algorithm for the optical thin case where the Poisson noise is high, the iteration-free Bjorkman & Wood method to reduce the calculation time, and the Fleck & Canfield diffusion approximation for extreme optical thick cells. The code is applied to model the appearance of active galactic nuclei (AGNs) at optical and infrared wavelengths. The AGN torus is clumpy and includes fluffy composite grains of various sizes made up of silicates and carbon. The dependence of the SED on the number of clumps in the torus and the viewing angle is studied. The appearance of the 10 μm silicate features in absorption or emission is discussed. The SED of the radio-loud quasar 3C 249.1 is fit by the AGN model and a cirrus component to account for the far-infrared emission.

  20. High-rate artificial lift

    SciTech Connect

    Clegg, J.D.

    1988-03-01

    This paper summarizes the major considerations in the selection, design, installation, operation, or repair of high-rate artificial-lift systems. The major types of artificial lift - sucker-rod pumps, gas-lift systems, electrical submersible pumps, hydraulic pumps and jets, and hydraulic turbine-driven pumps - will be discussed. An extensive bibliography of artificial-lift papers is included.

  1. The Subarcsecond Mid-infrared View of Local Active Galactic Nuclei. III. Polar Dust Emission

    NASA Astrophysics Data System (ADS)

    Asmus, D.; Hönig, S. F.; Gandhi, P.

    2016-05-01

    Recent mid-infrared (MIR) interferometric observations have shown that in a few active galactic nuclei (AGNs) the bulk of the infrared emission originates from the polar region above the putative torus, where only a little dust should be present. Here, we investigate whether such strong polar dust emission is common in AGNs. Out of 149 Seyferts in the MIR atlas of local AGNs, 21 show extended MIR emission on single-dish images. In 18 objects, the extended MIR emission aligns with the position angle (PA) of the system axis, established by [O iii], radio, polarization, and maser-based PA measurements. The relative amount of resolved MIR emission is at least 40% and scales with the [O iv] fluxes, implying a strong connection between the extended continuum and [O iv] emitters. These results together with the radio-quiet nature of the Seyferts support the scenario that the bulk of MIR emission is emitted by dust in the polar region and not by the torus, which would demand a new paradigm for the infrared emission structure in AGNs. The current low detection rate of polar dust in the AGNs of the MIR atlas is explained by the lack of sufficient high-quality MIR data and the requirements on the orientation, strength of narrow-line region, and distance of the AGNs. The James Webb Space Telescope will enable much deeper nuclear MIR studies with comparable angular resolution, allowing us to resolve the polar emission and surroundings in most of the nearby AGNs. Based on European Southern Observatory (ESO) observing programmes 60.A-9242, 074.A-9016, 075.B-0182, 075.B-0621, 075.B-0631, 075.B-0727, 075.B-0791, 075.B-0844, 076.B-0194, 076.B-0468, 076.B-0599, 076.B-0621, 076.B-0656, 076.B-0696, 076.B-0743, 077.B-0060, 077.B-0135, 077.B-0137, 077.B-0728, 078.B-0020, 078.B-0173, 078.B-0255, 078.B-0303, 080.B-0240, 080.B-0860, 081.B-0182, 082.B-0299, 083.B-0239, 083.B-0452, 083.B-0536, 083.B-0592, 084.B-0366, 084.B-0606, 084.B-0974, 085.B-0251, 085.B-0639, 086.B-0242, 086.B-0257, 086

  2. LARGE-SCALE CYCLOGENESIS, FRONTAL WAVES AND DUST ON MARS: MODELING AND DIAGNOSTIC CONSIDERATIONS

    NASA Astrophysics Data System (ADS)

    Hollingsworth, J.; Kahre, M.

    2009-12-01

    During late autumn through early spring, Mars’ northern middle and high latitudes exhibit very strong equator-to-pole mean temperature contrasts (i.e., baroclinicity). From data collected during the Viking era and recent observations from both the Mars Global Surveyor (MGS) and Mars Reconnaissance Orbiter (MRO) missions, this strong baroclinicity supports vigorous large-scale eastward traveling weather systems (i.e., transient synoptic-period waves). These systems also have accompanying sub-synoptic scale ramifications on the atmospheric environment through cyclonic/anticyclonic winds, intense deformations and contractions/dilations in temperatures, and sharp perturbations amongst atmospheric tracers (e.g., dust and volatiles/condensates). Mars’ northern-hemisphere frontal waves can exhibit extended meridional structure, and appear to be active agents in the planet’s dust cycle. Their parenting cyclones tend to develop, travel eastward, and decay preferentially within certain geographic regions (i.e., storm zones). We adapt a version of the NASA Ames Mars general circulation model (GCM) at high horizontal resolution that includes the lifting, transport and sedimentation of radiatively-active dust to investigate the nature of cyclogenesis and frontal-wave circulations (both horizontally and vertically), and regional dust transport and concentration within the atmosphere. Near late winter and early spring (Ls ˜ 320-350°), high-resolution simulations indicate that the predominant dust lifting occurs through wind-stress lifting, in particular over the Tharsis highlands of the western hemisphere and to a lesser extent over the Arabia highlands of the eastern hemisphere. The former region also indicates considerable interaction with regards to upslope/downslope (i.e., nocturnal) flows and the synoptic/subsynoptic-scale circulations associated with cyclogenesis whereby dust can be readily “focused” within a frontal-wave disturbance and carried downstream both

  3. Physical activity in people with asbestos related pleural disease and dust-related interstitial lung disease: An observational study.

    PubMed

    Dale, Marita T; McKeough, Zoe J; Munoz, Phillip A; Corte, Peter; Bye, Peter T P; Alison, Jennifer A

    2015-11-01

    This study aimed to measure the levels of physical activity (PA) in people with dust-related pleural and interstitial lung diseases and to compare these levels of PA to a healthy population. There is limited data on PA in this patient population and no previous studies have compared PA in people with dust-related respiratory diseases to a healthy control group. Participants with a diagnosis of a dust-related respiratory disease including asbestosis and asbestos related pleural disease (ARPD) and a healthy age- and gender-matched population wore the SenseWear(®) Pro3 armband for 9 days. Six-minute walk distance, Medical Outcomes Study 36-item short-form health survey and the Hospital Anxiety and Depression Scale were also measured. Fifty participants were recruited and 46 completed the study; 22 with ARPD, 10 with dust-related interstitial lung disease (ILD) and 14 healthy age-matched participants. The mean (standard deviation) steps/day were 6097 (1939) steps/day for dust-related ILD, 9150 (3392) steps/day for ARPD and 10,630 (3465) steps/day for healthy participants. Compared with the healthy participants, dust-related ILD participants were significantly less active as measured by steps/day ((mean difference 4533 steps/day (95% confidence interval (CI): 1888-7178)) and energy expenditure, ((mean difference 512 calories (95% CI: 196-827)) and spent significantly less time engaging in moderate, vigorous or very vigorous activities (i.e. >3 metabolic equivalents; mean difference 1.2 hours/day (95% CI: 0.4-2.0)). There were no differences in levels of PA between healthy participants and those with ARPD. PA was reduced in people with dust-related ILD but not those with ARPD when compared with healthy age and gender-matched individuals.

  4. The Covering Factor of Warm Dust in Weak Emission-line Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Zhang, Xudong; Liu, Yuan

    2016-10-01

    Weak emission-line active galactic nuclei (WLAGNs) are radio-quiet active galactic nuclei (AGNs) that have nearly featureless optical spectra. We investigate the ultraviolet to mid-infrared spectral energy distributions of 73 WLAGNs (0.4 < z < 3) and find that most of them are similar to normal AGNs. We also calculate the covering factor of warm dust of these 73 WLAGNs. No significant difference is indicated by a KS test between the covering factor of WLAGNs and normal AGNs in the common range of bolometric luminosity. The implication for several models of WLAGNs is discussed. The super-Eddington accretion is unlikely to be the dominant reason for the featureless spectrum of a WLAGN. The present results are still consistent with the evolution scenario, i.e., WLAGNs are in a special stage of AGNs.

  5. Effect of coal mine dust and clay extracts on the biological activity of the quartz surface.

    PubMed

    Stone, V; Jones, R; Rollo, K; Duffin, R; Donaldson, K; Brown, D M

    2004-04-01

    Modification of the quartz surface by aluminium salts and metallic iron have been shown to reduce the biological activity of quartz. This study aimed to investigate the ability of water soluble extracts of coal mine dust (CMD), low aluminium clays (hectorite and montmorillonite) and high aluminium clays (attapulgite and kaolin) to inhibit the reactivity of the quartz surface. DQ12 induced significant haemolysis of sheep erythrocytes in vitro and inflammation in vivo as indicated by increases in the total cell numbers, neutrophil cell numbers, MIP-2 protein and albumin content of bronchoalveolar lavage (BAL) fluid. Treatment of DQ12 with CMD extract prevented both haemolysis and inflammation. Extracts of the high aluminium clays (kaolin and attapulgite) prevented inhibition of DQ12 induced haemolysis, and the kaolin extract inhibited quartz driven inflammation. DQ12 induced haemolysis by coal mine dust and kaolin extract could be prevented by pre-treatment of the extracts with a cation chellator. Extracts of the low aluminium clays (montmorillonite and hectorite) did not prevent DQ12 induced haemolysis, although the hectorite extract did prevent inflammation. These results suggest that CMD, and clays both low and rich in aluminium, all contain soluble components (possibly cations) capable of masking the reactivity of the quartz surface. PMID:15093271

  6. Intermittent dust mass loss from activated asteroid P/2013 P5 (PANSTARRS)

    SciTech Connect

    Moreno, F.; Pozuelos, F.

    2014-02-01

    We present observations and models of the dust environment of activated asteroid P/2013 P5 (PANSTARRS). The object displayed a complex morphology during the observations, with the presence of multiple tails. We combined our own observations, all made with instrumentation attached to the 10.4 m Gran Telescopio Canarias on La Palma, with previously published Hubble Space Telescope images to build a model aimed at fitting all the observations. Altogether, the data cover a full three month period of observations which can be explained by intermittent dust loss. The most plausible scenario is that of an asteroid rotating with the spinning axis oriented perpendicular to the orbit plane and losing mass from the equatorial region, consistent with rotational break-up. Assuming that the ejection velocity of the particles (v ∼ 0.02-0.05 m s{sup –1}) corresponds to the escape velocity, the object diameter is constrained to ∼30-130 m for bulk densities 3000-1000 kg m{sup –3}.

  7. Submillimeter recombination lines in dust-obscured starbursts and active galactic nuclei

    SciTech Connect

    Scoville, N.; Murchikova, L.

    2013-12-10

    We examine the use of submillimeter (submm) recombination lines of H, He, and He{sup +} to probe the extreme ultraviolet (EUV) luminosity of starbursts (SBs) and active galactic nuclei (AGNs). We find that the submm recombination lines of H, He, and He{sup +} are in fact extremely reliable and quantitative probes of the EUV continuum at 13.6 eV to above 54.6 eV. At submm wavelengths, the recombination lines originate from low energy levels (n = 20-50). The maser amplification, which poses significant problems for quantitative interpretation of the higher n, radio frequency recombination lines, is insignificant. Lastly, at submm wavelengths, the dust extinction is minimal. The submm line luminosities are therefore directly proportional to the emission measures (EM{sub ION} = n{sub e} × n {sub ion} × volume) of their ionized regions. We also find that the expected line fluxes are detectable with ALMA and can be imaged at ∼0.''1 resolution in low redshift ultraluminous infrared galaxies. Imaging of the H I lines will provide accurate spatial and kinematic mapping of the star formation distribution in low-z IR-luminous galaxies, and the relative fluxes of the H I and He II recombination lines will strongly constrain the relative contributions of SBs and AGNs to the luminosity. The H I lines should also provide an avenue to constraining the submm dust extinction curve.

  8. DUST IN ACTIVE GALACTIC NUCLEI: ANOMALOUS SILICATE TO OPTICAL EXTINCTION RATIOS?

    SciTech Connect

    Lyu, Jianwei; Hao, Lei; Li, Aigen

    2014-09-01

    Dust plays a central role in the unification theory of active galactic nuclei (AGNs). However, little is known about the nature (e.g., size, composition) of the dust that forms a torus around the AGN. In this Letter, we report a systematic exploration of the optical extinction (A{sub V} ) and the silicate absorption optical depth (Δτ{sub 9.7}) of 110 type 2 AGNs. We derive A{sub V} from the Balmer decrement based on the Sloan Digital Sky Survey data, and Δτ{sub 9.7} from the Spitzer/InfraRed Spectrograph data. We find that with a mean ratio of (A{sub V} /Δτ{sub 9.7}) ≲ 5.5, the optical-to-silicate extinction ratios of these AGNs are substantially lower than that of the Galactic diffuse interstellar medium (ISM) for which A{sub V} /Δτ{sub 9.7} ≈ 18.5. We argue that the anomalously low A{sub V} /Δτ{sub 9.7} ratio could be due to the predominance of larger grains in the AGN torus compared to that in the Galactic diffuse ISM.

  9. HOT-DUST-POOR TYPE 1 ACTIVE GALACTIC NUCLEI IN THE COSMOS SURVEY

    SciTech Connect

    Hao Heng; Elvis, Martin; Civano, Francesca; Lanzuisi, Giorgio; Brusa, Marcella; Bongiorno, Angela; Lusso, Elisabeta; Zamorani, Gianni; Comastri, Andrea; Impey, Chris D.; Trump, Jonathan R.; Koekemoer, Anton M.; Le Floc'h, Emeric; Sanders, David; Salvato, Mara; Vignali, Cristian E-mail: elvis@cfa.harvard.ed

    2010-11-20

    We report a sizable class of type 1 active galactic nuclei (AGNs) with unusually weak near-infrared (1-3 {mu}m) emission in the XMM-COSMOS type 1 AGN sample. The fraction of these 'hot-dust-poor' AGNs increases with redshift from 6% at low redshift (z < 2) to 20% at moderate high redshift (2 < z < 3.5). There is no clear trend of the fraction with other parameters: bolometric luminosity, Eddington ratio, black hole mass, and X-ray luminosity. The 3 {mu}m emission relative to the 1 {mu}m emission is a factor of 2-4 smaller than the typical Elvis et al. AGN spectral energy distribution (SED), which indicates a 'torus' covering factor of 2%-29%, a factor of 3-40 smaller than required by unified models. The weak hot dust emission seems to expose an extension of the accretion disk continuum in some of the source SEDs. We estimate the outer edge of their accretion disks to lie at (0.3-2.0) x 10{sup 4} Schwarzschild radii, {approx}10-23 times the gravitational stability radii. Formation scenarios for these sources are discussed.

  10. Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

    DOE PAGES

    DeMott, P. J.; Prenni, A. J.; McMeeking, G. R.; Sullivan, R. C.; Petters, M. D.; Tobo, Y.; Niemand, M.; Möhler, O.; Snider, J. R.; Wang, Z.; et al

    2014-06-27

    Data from both laboratory studies and atmospheric measurements are used to develop a simple parametric description for the immersion freezing activity of natural mineral dust particles. Measurements made with the Colorado State University (CSU) continuous flow diffusion chamber (CFDC) when processing mineral dust aerosols at a nominal 105% relative humidity with respect to water (RHw) are taken to approximate the immersion freezing nucleation activity of particles. Ice active frozen fractions vs. temperature for dusts representative of Saharan and Asian desert sources were consistent with similar measurements in atmospheric dust plumes for a limited set of comparisons available. The parameterization developedmore » follows the form of one suggested previously for atmospheric particles of non-specific composition in quantifying ice nucleating particle concentrations as functions of temperature and the total number concentration of particles larger than 0.5 μm diameter. Such an approach does not explicitly account for surface area and time dependencies for ice nucleation, but sufficiently encapsulates the activation properties for potential use in regional and global modeling simulations, and possible application in developing remote sensing retrievals for ice nucleating particles. A correction factor is introduced to account for the apparent underestimate (by approximately 3, on average) of the immersion freezing fraction of mineral dust particles for CSU CFDC data processed at an RHw of 105% vs. maximum fractions active at higher RHw. Instrumental factors that affect activation behavior vs. RHw in CFDC instruments remain to be fully explored in future studies. Nevertheless, the use of this correction factor is supported by comparison to ice activation data obtained for the same aerosols from Aerosol Interactions and Dynamics of the Atmosphere (AIDA) expansion chamber cloud parcel experiments. Further comparison of the new parameterization to the immersion

  11. Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

    DOE PAGES

    DeMott, P. J.; Prenni, A. J.; McMeeking, G. R.; Sullivan, R. C.; Petters, M. D.; Tobo, Y.; Niemand, M.; Möhler, O.; Snider, J. R.; Wang, Z.; et al

    2015-01-13

    Data from both laboratory studies and atmospheric measurements are used to develop an empirical parameterization for the immersion freezing activity of natural mineral dust particles. Measurements made with the Colorado State University (CSU) continuous flow diffusion chamber (CFDC) when processing mineral dust aerosols at a nominal 105% relative humidity with respect to water (RHw) are taken as a measure of the immersion freezing nucleation activity of particles. Ice active frozen fractions vs. temperature for dusts representative of Saharan and Asian desert sources were consistent with similar measurements in atmospheric dust plumes for a limited set of comparisons available. The parameterizationmore » developed follows the form of one suggested previously for atmospheric particles of non-specific composition in quantifying ice nucleating particle concentrations as functions of temperature and the total number concentration of particles larger than 0.5 μm diameter. Such an approach does not explicitly account for surface area and time dependencies for ice nucleation, but sufficiently encapsulates the activation properties for potential use in regional and global modeling simulations, and possible application in developing remote sensing retrievals for ice nucleating particles. A calibration factor is introduced to account for the apparent underestimate (by approximately 3, on average) of the immersion freezing fraction of mineral dust particles for CSU CFDC data processed at an RHw of 105% vs. maximum fractions active at higher RHw. Instrumental factors that affect activation behavior vs. RHw in CFDC instruments remain to be fully explored in future studies. Nevertheless, the use of this calibration factor is supported by comparison to ice activation data obtained for the same aerosols from Aerosol Interactions and Dynamics of the Atmosphere (AIDA) expansion chamber cloud parcel experiments. Further comparison of the new parameterization, including calibration

  12. Climatic controls of the interannual to decadal variability in Saudi Arabian dust activity: Towards the development of a seasonal prediction tool

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Notaro, M.; Liu, Z.; Alkolibi, F.; Fadda, E.; Bakhrjy, F.

    2013-12-01

    Atmospheric dust significantly influences the climate system, as well as human life in Saudi Arabia. Skillful seasonal prediction of dust activity with climatic variables will help prevent some negative social impacts of dust storms. Yet, the climatic regulators on Saudi Arabian dust activity remain largely unaddressed. Remote sensing and station observations show consistent seasonal cycles in Saudi Arabian dust activity, which peaks in spring and summer. The climatic controls on springtime and summertime Saudi Arabian dust activity during 1975-2010 are studied using observational and reanalysis data. Empirical Orthogonal Function (EOF) of the observed Saudi Arabian dust storm frequency shows a dominant homogeneous pattern across the country, which has distinct interannual and decadal variations, as revealed by the power spectrum. Regression and correlation analyses reveal that Saudi Arabian dust activity is largely tied to precipitation on the Arabian Peninsula in spring and northwesterly (Shamal) wind in summer. On the seasonal-interannual time scale, warm El Niño-Southern Oscillation (ENSO) phase (El Niño) in winter-to-spring inhibits spring dust activity by increasing the precipitation over the Rub'al Khali Desert, a major dust source region on the southern Arabian Peninsula; warm ENSO and warm Indian Ocean Basin Mode (IOBM) in winter-to-spring favor less summer dust activity by producing anomalously low sea-level pressure over eastern north Africa and Arabian Peninsula, which leads to the reduced Shamal wind speed. The decadal variation in dust activity is likely associated with the Atlantic Multidecadal Oscillation (AMO), which impacts Sahel rainfall and North African dust, and likely dust transport to Saudi Arabia. The Pacific Decadal Oscillation (PDO) and tropical Indian Ocean SST also have influence on the decadal variation in Saudi Arabian dust activity, by altering precipitation over the Arabian Peninsula and summer Shamal wind speed. Using eastern

  13. Triton's streaks as windblown dust

    NASA Technical Reports Server (NTRS)

    Sagan, Carl; Chyba, Christopher

    1990-01-01

    Explanations for the surface streaks observed by Voyager 2 on Triton's southern hemisphere are discussed. It is shown that, despite Triton's tenuous atmosphere, low-cohesion dust trains with diameters of about 5 micron or less may be carried into suspension by aeolian surface shear stress, given expected geostrophic wind speeds of about 10 m/s. For geyser-like erupting dust plumes, it is shown that dust-settling time scales and expected wind velocities can produce streaks with length scales in good agreement with those of the streaks. Thus, both geyserlike eruptions or direct lifting by surface winds appear to be viable mechanisms for the origin of the streaks.

  14. Dust Grains and the Luminosity of Circumnuclear Water Masers in Active Galaxies

    NASA Technical Reports Server (NTRS)

    Collison, Alan J.; Watson, William D.

    1995-01-01

    In previous calculations for the luminosities of 22 GHz water masers, the pumping is reduced and ultimately quenched with increasing depth into the gas because of trapping of the infrared (approximately equals 30-150 micrometers), spectral line radiation of the water molecule. When the absorption (and reemission) of infrared radiation by dust grains is included, we demonstrate that the pumping is no longer quenched but remains constant with increasing optical depth. A temperature difference between the grains and the gas is required. Such conditions are expected to occur, for example, in the circumnuclear masing environments created by X-rays in active galaxies. Here, the calculated 22 GHz maser luminosities are increased by more than an order of magnitude. Application to the well-studied, circumnuclear masing disk in the galaxy NGC 4258 yields a maser luminosity near that inferred from observations if the observed X-ray flux is assumed to be incident onto only the inner surface of the disk.

  15. Waste Package Lifting Calculation

    SciTech Connect

    H. Marr

    2000-05-11

    The objective of this calculation is to evaluate the structural response of the waste package during the horizontal and vertical lifting operations in order to support the waste package lifting feature design. The scope of this calculation includes the evaluation of the 21 PWR UCF (pressurized water reactor uncanistered fuel) waste package, naval waste package, 5 DHLW/DOE SNF (defense high-level waste/Department of Energy spent nuclear fuel)--short waste package, and 44 BWR (boiling water reactor) UCF waste package. Procedure AP-3.12Q, Revision 0, ICN 0, calculations, is used to develop and document this calculation.

  16. The physics of wind-blown sand and dust.

    PubMed

    Kok, Jasper F; Parteli, Eric J R; Michaels, Timothy I; Karam, Diana Bou

    2012-10-01

    The transport of sand and dust by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This paper presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.

  17. 4. DETAIL OF VERTICAL LIFT SPAN SHOWING CONCRETE PIERS, LIFT ...

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

    4. DETAIL OF VERTICAL LIFT SPAN SHOWING CONCRETE PIERS, LIFT TOWERS, AND THROUGH TRUSS, LOOKING SOUTHEAST. - Shippingsport Bridge, Spanning Illinois River at State Route 51, La Salle, La Salle County, IL

  18. Interior view of lift mechanism area of eastern lift span ...

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

    Interior view of lift mechanism area of eastern lift span looking south, showing trunion gears at left and right, and counterweight above. - Arlington Memorial Bridge, Spanning Potomac River between Lincoln Memorial & Arlington National Cemetery, Washington, District of Columbia, DC

  19. Interior view of lift mechanism area of eastern lift span, ...

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

    Interior view of lift mechanism area of eastern lift span, showing trunion gears at left and right, and counterweight above. - Arlington Memorial Bridge, Spanning Potomac River between Lincoln Memorial & Arlington National Cemetery, Washington, District of Columbia, DC

  20. Dust, Climate, and Human Health

    NASA Technical Reports Server (NTRS)

    Maynard, Nancy G.

    2003-01-01

    Air pollution from both natural and anthropogenic causes is considered to be one of the most serious world-wide environment-related health problems, and is expected to become worse with changes in the global climate. Dust storms from the atmospheric transport of desert soil dust that has been lifted and carried by the winds - often over significant distances - have become an increasingly important emerging air quality issue for many populations. Recent studies have shown that the dust storms can cause significant health impacts from the dust itself as well as the accompanying pollutants, pesticides, metals, salt, plant debris, and other inorganic and organic materials, including viable microorganisms (bacteria, viruses and fungi). For example, thousands of tons of Asian desert sediments, some containing pesticides and herbicides from farming regions, are commonly transported into the Arctic during dust storm events. These chemicals have been identified in animal and human tissues among Arctic indigenous populations. Millions of tons of airborne desert dust are being tracked by satellite imagery, which clearly shows the magnitude as well as the temporal and spatial variability of dust storms across the "dust belt" regions of North Africa, the Middle East, and China. Ths paper summarizes the most recent findings on the effects of airborne desert dust on human health as well as potential climate influences on dust and health.

  1. Dust, Climate, and Human Health

    NASA Technical Reports Server (NTRS)

    Maynard, Nancy G.

    2003-01-01

    Air pollution from both natural and anthropogenic causes is considered to be one of the most serious world-wide environment-related health problems, and is expected to become worse with changes in the global climate. Dust storms from the atmospheric transport of desert soil dust that has been lifted and carried by the winds - often over significant distances - have become an increasingly important emerging air quality issue for many populations. Recent studies have shown that the dust storms can cause significant health impacts from the dust itself as well as the accompanying pollutants, pesticides, metals, salt, plant debris, and other inorganic and organic materials, including viable microorganisms (bacteria, viruses and fungi). For example, thousands of tons of Asian desert sediments, some containing pesticides and herbicides from farming regions, are commonly transported into the Arctic during dust storm events. These chemicals have been identified in animal and human tissues among Arctic indigenous populations. Millions of tons of airborne desert dust are being tracked by satellite imagery, which clearly shows the magnitude as well as the temporal and spatial variability of dust storms across the "dust belt" regions of North Africa, the Middle East, and China. This paper summarizes the most recent findings on the effects of airborne desert dust on human health as well as potential climate influences on dust and health.

  2. Dust, Climate, and Human Health

    NASA Astrophysics Data System (ADS)

    Maynard, N. G.

    2003-12-01

    Air pollution from both natural and anthropogenic causes is considered to be one of the most serious world-wide environment-related health problems, and is expected to become worse with changes in the global climate. Dust storms from the atmospheric transport of desert soil dust that has been lifted and carried by the winds - often over significant distances - have become an increasingly important emerging air quality issue for many populations. Recent studies have shown that the dust storms can cause significant health impacts from the dust itself as well as the accompanying pollutants, pesticides, metals, salt, plant debris, and other inorganic and organic materials, including viable microorganisms (bacteria, viruses and fungi). For example, thousands of tons of Asian desert sediments, some containing pesticides and herbicides from farming regions, are commonly transported into the Arctic during dust storm events. These chemicals have been identified in animal and human tissues among Arctic indigenous populations. Millions of tons of airborne desert dust are being tracked by satellite imagery, which clearly shows the magnitude as well as the temporal and spatial variability of dust storms across the "dust belt" regions of North Africa, the Middle East, and China. This paper summarizes the most recent findings on the effects of airborne desert dust on human health as well as potential climate influences on dust and health

  3. Star and Dust Formation Activities in AzTEC-3: A Starburst Galaxy at z=5.3

    NASA Technical Reports Server (NTRS)

    Dwek, Eliahu

    2011-01-01

    Analyses of of high-redshift ultraluminous infrared (IR) galaxies traditionally use the observed optical to submillimeter spectral energy distribution (SED) and estimates of the dynamical mass as observational constraints to derive the star formation rate (SFR), the stellar mass, and age of these objects. In this lecture we add this constraint to the analysis of AzTEC-3, a starburst galaxy at z=5.3. We construct different stellar and chemical evolutionary scenarios, constrained to produce the inferred dust mass and observed luminosity before the associated stellar mass exceeds the observational limit. A robust result of our models is that all scenarios require most of the radiating dust mass to have been accreted in molecular clouds. Our new procedure highlights the importance of a multiwavelength approach, and of the use of dust evolution models in constraining the age and the star formation activity and history in galaxies.

  4. Star and Dust Formation Activities in AzTEC-3: A Starburst Galaxy at z equals 5.3

    NASA Technical Reports Server (NTRS)

    Dwek, Eliahu

    2011-01-01

    Analyses of of high-redshift ultraluminous infrared (IR) galaxies traditionally use the observed optical to submillimeter spectral energy distribution (SED) and estimates of the dynamical mass as observational constraints to derive the star formation rate (SFR), the stellar mass, and age of these objects. In this lecture we add this constraint to the analysis of AzTEC-3, a starburst galaxy at z=5.3. We construct different stellar and chemical evolutionary scenarios, constrained to produce the inferred dust mass and observed luminosity before the associated stellar mass exceeds the observational limit. A robust result of our models is that all scenarios require most of the radiating dust mass to have been accreted in molecular clouds. Our new procedure highlights the importance of a multi wavelength approach, and of the use of dust evolution models in constraining the age and the star formation activity and history in galaxies.

  5. Star Dust Formation Activities in AzTEC-3: A Starburst Galaxy at z=5.3

    NASA Technical Reports Server (NTRS)

    Dwek, Eliahu

    2011-01-01

    Analyses of of high-redshift ultraluminous infrared OR) galaxies traditionally use the observed optical to submillimeter spectral energy distribution (SED) and estimates of the dynamical mass as observational constraints to derive the star formation rate (SFR), the stellar mass, and age of these objects. In this lecture we add this constraint to the analysis of AzTEC-3, a starburst galaxy at z=5.3. We construct different stellar and chemical evolutionary scenarios, constrained to produce the inferred dust mass and observed luminosity before the associated stellar mass exceeds the observational limit. A robust result of our models is that all scenarios require most of the radiating dust mass to have been accreted in molecular clouds. Our new procedure highlights the importance of a multi wavelength approach, and of the use of dust evolution models in constraining the age and the star formation activity and history in galaxies.

  6. Acaricidal activities against house dust mites of spearmint oil and its constituents.

    PubMed

    Yang, Ji-Yeon; Kim, Min-Gi; Lee, Sung-Eun; Lee, Hoi-Seon

    2014-02-01

    The aim of this study was to evaluate the acaricidal activities of spearmint oil and carvone derivatives against house dust mites using contact and fumigant toxicity bioassays to replace benzyl benzoate as a synthetic acaricide. Based on the LD50 values, the contact toxicity bioassay revealed that dihydrocarvone (0.95 and 0.88 µg/cm2) was 7.7 and 6.8 times more toxic than benzyl benzoate (7.33 and 6.01 µg/cm2) against Dermatophagoides farinae and Dermatophagoides pteronyssinus, respectively, followed by carvone (3.78 and 3.23 µg/cm2), spearmint oil (5.16 and 4.64 µg/cm2), carveol (6.00 and 5.80 µg/cm2), and dihydrocarveol (8.23 and 7.10 µg/cm2). Results of the fumigant toxicity bioassay showed that dihydrocarvone (2.73 and 2.16 µg/cm2) was approximately 4.0 and 4.8 times more effective than benzyl benzoate (11.00 and 10.27 µg/cm2), followed by carvone (6.63 and 5.78 µg/cm2), carveol (7.58 and 7.24 µg/cm2), spearmint oil (9.55 and 8.10 µg/cm2), and dihydrocarveol (9.79 and 8.14 µg/cm2). Taken together, spearmint oil and carvone derivatives are a likely viable alternative to synthetic acaricides for managing house dust mites.

  7. Hydraulic lifting device

    NASA Technical Reports Server (NTRS)

    Terrell, Kyle (Inventor)

    1990-01-01

    A piston and cylinder assembly is disclosed which is constructed of polyvinyl chloride that uses local water pressure to perform small lifting tasks. The chamber is either pressurized to extend the piston or depressurized to retract the piston. The present invention is best utilized for raising and lowering toilet seats.

  8. Lifting as You Climb

    ERIC Educational Resources Information Center

    Sullivan, Debra R.

    2009-01-01

    This article addresses leadership themes and answers leadership questions presented to "Exchange" by the Panel members who attended the "Exchange" Panel of 300 Reception in Dallas, Texas, last November. There is an old proverb that encourages people to lift as they climb: "While you climb a mountain, you must not forget others along the way." With…

  9. SYMPOSIUM #127 – ARE POLYBROMINATED DIPHENYL ETHERS FROM HOUSEHOLD DUST BIOAVAILABLE AND BIOLOGICALLY ACTIVE?

    EPA Science Inventory

    Recently, household dust has been implicated as a major source of polybrominated diphenyl ether (PBDE) exposure in humans. This finding may have important implications for young children, who are thought to ingest more dust than adults and may be more susceptible to some of the ...

  10. [A method of mutagenic activity testing for coal tar in atmospheric dust].

    PubMed

    Krogulski, A; Borkowska, M

    1996-01-01

    For assessing of the environmental contamination with potentially carcinogenic mutagens the possibility of the measurement of the mutagenic activity of the substances absorbed on dust suspended in air would be important. These substances include at least several hundreds of organic compounds. Only a small part of them have been studied in detail, and, on the other hand, it is known that at least a score of them are carcinogenic. Additionally, the presence of some of them can change significantly the action of other ones. Because of that, the effects of a mixture of these substances should be studied as a whole. The fact that the discussed contaminants are present in the air and can be transported over great distances causes that they are dangerous to man both directly (when inhaled) and trough contamination of water, soil and food. Parallel use in the described method of two cross-bred strains of fruit flies made possible separate assessment of the activity of mutagens and promutagens requiring activation in presence of cytochrome P 450. The use of the eukaryotic organism in which mutations are observed in many cells in one individual (about 2500) enables reliable data to be obtained about the degree of human health risk.

  11. Helicopter Toy and Lift Estimation

    ERIC Educational Resources Information Center

    Shakerin, Said

    2013-01-01

    A $1 plastic helicopter toy (called a Wacky Whirler) can be used to demonstrate lift. Students can make basic measurements of the toy, use reasonable assumptions and, with the lift formula, estimate the lift, and verify that it is sufficient to overcome the toy's weight. (Contains 1 figure.)

  12. Helicopter Toy and Lift Estimation

    NASA Astrophysics Data System (ADS)

    Shakerin, Said

    2013-05-01

    A1 plastic helicopter toy (called a Wacky Whirler) can be used to demonstrate lift. Students can make basic measurements of the toy, use reasonable assumptions and, with the lift formula, estimate the lift, and verify that it is sufficient to overcome the toy's weight.

  13. Towards a physical model of dust tori in Active Galactic Nuclei. Radiative transfer calculations for a hydrostatic torus model

    NASA Astrophysics Data System (ADS)

    Schartmann, M.; Meisenheimer, K.; Camenzind, M.; Wolf, S.; Henning, Th.

    2005-07-01

    We explore physically self-consistent models of dusty molecular tori in Active Galactic Nuclei (AGN) with the goal of interpreting VLTI observations and fitting high resolution mid-IR spectral energy distributions (SEDs). The input dust distribution is analytically calculated by assuming hydrostatic equilibrium between pressure forces - due to the turbulent motion of the gas clouds - and gravitational and centrifugal forces as a result of the contribution of the nuclear stellar distribution and the central black hole. For a fully three-dimensional treatment of the radiative transfer problem through the tori we employ the Monte Carlo code MC3D. We find that in homogeneous dust distributions the observed mid-infrared emission is dominated by the inner funnel of the torus, even when observing along the equatorial plane. Therefore, the stratification of the distribution of dust grains - both in terms of size and composition - cannot be neglected. In the current study we only include the effect of different sublimation radii which significantly alters the SED in comparison to models that assume an average dust grain property with a common sublimation radius, and suppresses the silicate emission feature at 9.7~μm. In this way we are able to fit the mean SED of both type I and type II AGN very well. Our fit of special objects for which high angular resolution observations (≤0.3´´) are available indicates that the hottest dust in NGC 1068 reaches the sublimation temperature while the maximum dust temperature in the low-luminosity AGN Circinus falls short of 1000 K.

  14. Determining safe limits for significant task parameters during manual lifting.

    PubMed

    Singh, Ravindra Pratrap; Batish, Ajay; Singh, Tejinder Pal

    2014-04-01

    This experimental study investigated the effect of lifting task parameters (i.e., lifting weight, frequency, coupling, asymmetric angle, and vertical, horizontal, and travel distances) for various dynamic human lifting activities on the ground reaction forces of workers. Ten male workers loaded containers from different levels asymmetrically during experimental trials. The experimental design evolved using Taguchi's Fractional Factorial Experiments. Three factors (lifting weight, frequency, and vertical distance) were observed to be significant. The results showed that vertical reaction forces increase when workers lift weight from floor to shoulder height frequently. It was also observed that instantaneous loading rate increases with more weight, vertical distance, and frequency; a significant extra loading rate is required to change the lower level of load, frequency, and vertical distance to higher levels. Safe limits for significant factors were determined to result in optimal performance of the manual lifting task.

  15. Lift performance and lumbar loading in standing and seated lifts.

    PubMed

    Middleton, Kane J; Carstairs, Greg L; Ham, Daniel J

    2016-09-01

    This study investigated the effect of posture on lifting performance. Twenty-three male soldiers lifted a loaded box onto a platform in standing and seated postures to determine their maximum lift capacity and maximum acceptable lift. Lift performance, trunk kinematics, lumbar loads, anthropometric and strength data were recorded. There was a significant main effect for lift effort but not for posture or the interaction. Effect sizes showed that lumbar compression forces did not differ between postures at lift initiation (Standing 5566.2 ± 627.8 N; Seated 5584.0 ± 16.0) but were higher in the standing posture (4045.7 ± 408.3 N) when compared with the seated posture (3655.8 ± 225.7 N) at lift completion. Anterior shear forces were higher in the standing posture at both lift initiation (Standing 519.4 ± 104.4 N; Seated 224.2 ± 9.4 N) and completion (Standing 183.3 ± 62.5 N; Seated 71.0 ± 24.2 N) and may have been a result of increased trunk flexion and a larger horizontal distance of the mass from the L5-S1 joint. Practitioner Summary: Differences between lift performance and lumbar forces in standing and seated lifts are unclear. Using a with-in subjects repeated measures design, we found no difference in lifted mass or lumbar compression force at lift initiation between standing and seated lifts.

  16. HiRISE Wind Measurements of Martian Dust Devils

    NASA Astrophysics Data System (ADS)

    Choi, D. S.; Dundas, C. M.

    2011-12-01

    We report direct measurements of the winds within Martian dust devils from HiRISE imagery. The central color swath of the HiRISE instrument has three separate CCDs and color filters that observe the surface in rapid cadence. Active features, such as dust devils, appear in motion when serendipitously captured by this region of the instrument. Though apparent movement of cloud features can be attributed to parallax from the spacecraft's motion, we determine that this is a relatively minor effect in our observations. Our image animations reveal clear circulatory motion within dust devils separate from their tangential motion across the Martian surface. Both manual and automated tracking of dust devil clouds reveal tangential winds that approach 20-30 m/s in some cases. These winds are sufficient to induce a ˜1% decrease in atmospheric pressure within the dust devil core relative to ambient, facilitating the lifting of dust particles into the Martian atmosphere. Finally, radial velocity profiles of dust devils constructed from our automated measurements test the Rankine vortex model for dust devil dynamics: the vortex consists of an interior region in solid body rotation and an outer region where tangential velocity decreases as a function of r-1. Our profiles successfully reveal the solid body rotation component in the interior, but fail to conclusively illuminate the profile in the outer regions of the vortex. One profile provides evidence for a velocity decrease as a function of r-1/2, instead of r-1, suggestive of surface friction effects. However, other profiles do not support this observation, or do not contain enough measurements to produce meaningful insights.

  17. long duration dust storm sequences on Mars

    NASA Astrophysics Data System (ADS)

    Wang, H.

    2012-12-01

    The Mars Global Surveyor (MGS) Mars Observer Camera (MOC) and Mars Reconnaissance Orbiter (MRO) Mars Color Imager (MARCI) Mars daily global maps have revealed new characteristics for long duration dust storm sequences. These dust storm sequences have long histories of more than a week, travel long distances out of their origination region, and influence large areas in different regions of the planet. During the Ls = 180 - 360 season, except for global dust storms which involve multiple remote dust lifting centers and generally expand explosively from the southern hemisphere northward, other long-lived dust storm sequences usually travel southward through the Acidalia-Chryse, Utopia-Isidis or Arcadia-Amazonis channels with subsequent dust lifting along the way. Sometimes, they penetrate remarkably deep to the southern high latitudes, producing fantastic display of dust band. During the rest of the year, long duration dust storm sequences usually originate from the Argyre/Solis, Hellas/Noachis, or Cimmeria/Sirenum area and travel northward toward the southern low latitudes. Each route exhibits its own peculiar characteristics. We will present our results about these long duration dust storm sequences summarized from the complete archive of MGS MOC daily global maps and two years of MRO MARCI daily global maps. The systematic daily nearly global coverage of these maps makes it feasible to reconstruct the history of long duration dust storm sequences with detail.

  18. Armature lift windmill

    SciTech Connect

    Willmouth, R. W.

    1985-04-02

    Airfoils are secured to the frame of a vertical axis windmill to provide vertical lift to a rotatable vertical shaft and to armatures of electrical generators, thereby eliminating friction between each armature and its end bearing as well as between the vertical shaft and its end bearing. An indicator provides an indication that the generators of the windmill are generating an alternating electrical current having at least a predetermined voltage magnitude.

  19. Enhanced Rescue Lift Capability

    NASA Technical Reports Server (NTRS)

    Young, Larry A.

    2007-01-01

    The evolving and ever-increasing demands of emergency response and disaster relief support provided by rotorcraft dictate, among other things, the development of enhanced rescue lift capability for these platforms. This preliminary analysis is first-order in nature but provides considerable insight into some of the challenges inherent in trying to effect rescue using a unique form of robotic rescue device deployed and operated from rotary-wing aerial platforms.

  20. Powered-lift aircraft technology

    NASA Technical Reports Server (NTRS)

    Deckert, W. H.; Franklin, J. A.

    1989-01-01

    Powered lift aircraft have the ability to vary the magnitude and direction of the force produced by the propulsion system so as to control the overall lift and streamwise force components of the aircraft, with the objective of enabling the aircraft to operate from minimum sized terminal sites. Power lift technology has contributed to the development of the jet lift Harrier and to the forth coming operational V-22 Tilt Rotor and the C-17 military transport. This technology will soon be expanded to include supersonic fighters with short takeoff and vertical landing capability, and will continue to be used for the development of short- and vertical-takeoff and landing transport. An overview of this field of aeronautical technology is provided for several types of powered lift aircraft. It focuses on the description of various powered lift concepts and their operational capability. Aspects of aerodynamics and flight controls pertinent to powered lift are also discussed.

  1. The Dust Content and Opacity of Actively Star-Forming Galaxies

    NASA Technical Reports Server (NTRS)

    Calzetti, Daniela; Armus, Lee; Bohlin, Ralph C.; Kinney, Anne L.; Koornneef, Jan; Storchi-Bergmann, Thaisa

    2000-01-01

    We present far-infrared (FIR) photometry at 150 and 205 micron(s) of eight low-redshift starburst galaxies obtained with the Infrared Space Observatory (ISO) ISOPHOT. Five of the eight galaxies are detected in both wave bands, and these data are used, in conjunction with IRAS archival photometry, to model the dust emission at lambda approximately greater than 40 microns. The FIR spectral energy distributions (SEDs) are best fitted by a combination of two modified Planck functions, with T approx. 40 - 55 K (warm dust) and T approx. 20-23 K (cool dust) and with a dust emissivity index epsilon = 2. The cool dust can be a major contributor to the FIR emission of starburst galaxies, representing up to 60% of the total flux. This component is heated not only by the general interstellar radiation field, but also by the starburst itself. The cool dust mass is up to approx. 150 times larger than the warm dust mass, bringing the gas-to-dust ratios of the starbursts in our sample close to Milky Way values, once resealed for the appropriate metallicity. The ratio between the total dust FIR emission in the range 1-1000 microns and the IRAS FIR emission in the range 40 - 120 microns is approx. 1.75, with small variations from galaxy to galaxy. This ratio is about 40% larger than previously inferred from data at millimeter wavelengths. Although the galaxies in our sample are generally classified as "UV bright," for four of them the UV energy emerging shortward of 0.2 microns is less than 15% of the FIR energy. On average, about 30% of the bolometric flux is coming out in the UV-to-near-IR wavelength range; the rest is emitted in the FIR. Energy balance calculations show that the FIR emission predicted by the dust reddening of the UV-to-near-IR stellar emission is within a factor of approx. 2 of the observed value in individual galaxies and within 20% when averaged over a large sample. If our sample of local starbursts is representative of high-redshift (z approx. greater than 1

  2. Warm dust and aromatic bands as quantitative probes of star-formation activity

    NASA Astrophysics Data System (ADS)

    Förster Schreiber, N. M.; Roussel, H.; Sauvage, M.; Charmandaris, V.

    2004-05-01

    We combine samples of spiral galaxies and starburst systems observed with ISOCAM on board ISO to investigate the reliability of mid-infrared dust emission as a quantitative tracer of star formation activity. The total sample covers very diverse galactic environments and probes a much wider dynamic range in star formation rate density than previous similar studies. We find that both the monochromatic 15 μm continuum and the 5-8.5 μm emission constitute excellent indicators of the star formation rate as quantified by the Lyman continuum luminosity LLyc, within specified validity limits which are different for the two tracers. Normalized to projected surface area, the 15 μm continuum luminosity Σ15 μm,ct is directly proportional to ΣLyc over several orders of magnitude. Two regimes are distinguished from the relative offsets in the observed relationship: the proportionality factor increases by a factor of ≈5 between quiescent disks in spiral galaxies, and moderate to extreme star-forming environments in circumnuclear regions of spirals and in starburst systems. The transition occurs near ΣLyc ˜ 102 L⊙ pc-2 and is interpreted as due to very small dust grains starting to dominate the emission at 15 μm over aromatic species above this threshold. The 5-8.5 μm luminosity per unit projected area is also directly proportional to the Lyman continuum luminosity, with a single conversion factor from the most quiescent objects included in the sample up to ΣLyc ˜ 104 L⊙ pc-2, where the relationship then flattens. The turnover is attributed to depletion of aromatic band carriers in the harsher conditions prevailing in extreme starburst environments. The observed relationships provide empirical calibrations useful for estimating star formation rates from mid-infrared observations, much less affected by extinction than optical and near-infrared tracers in deeply embedded H II regions and obscured starbursts, as well as for theoretical predictions from evolutionary

  3. A SUBSTANTIAL DUST DISK SURROUNDING AN ACTIVELY ACCRETING FIRST-ASCENT GIANT STAR

    SciTech Connect

    Melis, C.; Zuckerman, B.; Rhee, Joseph H.; Metchev, Stanimir; Song, Inseok

    2009-05-10

    We report identification of the first unambiguous example of what appears to be a new class of first-ascent giant stars that are actively accreting gas and dust and that are surrounded by substantial dusty disks. These old stars, who are nearing the end of their lives, are experiencing a rebirth into characteristics typically associated with newborn stars. The F2-type first-ascent giant star TYC 4144 329 2 is in a wide separation binary system with an otherwise normal G8 IV star, TYC 4144 329 1. From Keck near-infrared imaging and high-resolution spectroscopy, we are able to determine that these two stars are {approx}1 Gyr old and reside at a distance of {approx}550 pc. One possible explanation for the origin of the accreting material is common-envelope interaction with a low-mass stellar or substellar companion. The gaseous and dusty material around TYC 4144 329 2, as it is similar to the primordial disks observed around young classical T Tauri stars, could potentially give rise to a new generation of planets and/or planetesimals.

  4. Comparative performance of cement kiln dust and activated carbon in removal of cadmium from aqueous solutions.

    PubMed

    El-Refaey, Ahmed A

    2016-01-01

    This study compared the performance of cement kiln dust (CKD) as industrial byproduct and commercially activated carbon (AC) as adsorbent derived from agricultural waste for the removal of cadmium (Cd(2+)) from aqueous solutions. CKD and AC were characterized by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) and surface areas demonstrate the differences of physicochemical properties. Batch equilibrium experiments were conducted for various intervals extended to 96 h at 20, 25 and 30°C to investigate the efficiency of the sorbents in the removal of Cd(2+). CKD expressed high affinity for removal of Cd(2+) and was not affected by temperature, while AC was significantly affected, which reflects dissimilarity in the retention mechanisms defendant in CKD and those pursued by AC. The results were explained by changes of FTIR and SEM images before and after sorption experiments. The suggestion is that electrostatic ion exchange and complex reactions are the main mechanisms for Cd(2+) removal. The kinetic data were evaluated by fractional power, Elovich, pseudo-first order and pseudo-second-order kinetic models. The pseudo-second-order kinetic model was found to correlate with the experimental data well. These results revealed that CKD can be used as a cost-effective and efficient sorbent for Cd(2+) removal in comparison with AC.

  5. Comparative performance of cement kiln dust and activated carbon in removal of cadmium from aqueous solutions.

    PubMed

    El-Refaey, Ahmed A

    2016-01-01

    This study compared the performance of cement kiln dust (CKD) as industrial byproduct and commercially activated carbon (AC) as adsorbent derived from agricultural waste for the removal of cadmium (Cd(2+)) from aqueous solutions. CKD and AC were characterized by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) and surface areas demonstrate the differences of physicochemical properties. Batch equilibrium experiments were conducted for various intervals extended to 96 h at 20, 25 and 30°C to investigate the efficiency of the sorbents in the removal of Cd(2+). CKD expressed high affinity for removal of Cd(2+) and was not affected by temperature, while AC was significantly affected, which reflects dissimilarity in the retention mechanisms defendant in CKD and those pursued by AC. The results were explained by changes of FTIR and SEM images before and after sorption experiments. The suggestion is that electrostatic ion exchange and complex reactions are the main mechanisms for Cd(2+) removal. The kinetic data were evaluated by fractional power, Elovich, pseudo-first order and pseudo-second-order kinetic models. The pseudo-second-order kinetic model was found to correlate with the experimental data well. These results revealed that CKD can be used as a cost-effective and efficient sorbent for Cd(2+) removal in comparison with AC. PMID:27054742

  6. Video based lifting technique coding system.

    PubMed

    Hsiang, S M; Brogmus, G E; Martin, S E; Bezverkhny, I B

    1998-03-01

    Despite automation and improved working conditions, many materials in industry are still handled manually. Among the basic activities involved in manual materials handling, lifting is the one most frequently associated with low-back pain (LBP). Biomechanical analysis techniques have been used to better understand the risk factors associated with manual handling, but because these techniques require specialized equipment, highly trained personnel, and interfere with normal business operations, they are limited in their usefulness. A video based lifting technique analysis system (the VidLiTeCTM System) is presented that provides for quantifiable non-invasive biomechanical analysis of the dynamic features of lifting with high inter-coder reliability and low sensitivity to absolute errors. Analysis of results from a laboratory experiment and from field-collected videotape are described that support the reliability, sensitivity, and accuracy claims of the VidLiTeCTM System. The VidLiTeCTM System allows technicians with minimal training and low-tech equipment (a camcorder) to collect large sets of lifting data without interfering with normal business operations. A reasonably accurate estimate of the peak compressive force on the L5/S1 joint can be made from the data collected. Such a system can be used to collect quantified data on lifting techniques that can be related to LBP reporting.

  7. TMI-2 reactor vessel plenum final lift

    SciTech Connect

    Wilson, D C

    1986-01-01

    Removal of the plenum assembly from the TMI-2 reactor vessel was necessary to gain access to the core region for defueling. The plenum was lifted from the reactor vessel by the polar crane using three specially designed pendant assemblies. It was then transferred in air to the flooded deep end of the refueling canal and lowered onto a storage stand where it will remain throughout the defueling effort. The lift and transfer were successfully accomplished on May 15, 1985 in just under three hours by a lift team located in a shielded area within the reactor building. The success of the program is attributed to extensive mockup and training activities plus thorough preparations to address potential problems. 54 refs.

  8. Acaricidal activities of some essential oils and their monoterpenoidal constituents against house dust mite, Dermatophagoides pteronyssinus (Acari: Pyroglyphidae)

    PubMed Central

    Saad, El-Zemity; Hussien, Rezk; Saher, Farok; Ahmed, Zaitoon

    2006-01-01

    The acaricidal activities of fourteen essential oils and fourteen of their major monoterpenoids were tested against house dust mites Dermatophagoides pteronyssinus. Five concentrations were used over two different time intervals 24 and 48 h under laboratory conditions. In general, it was noticed that the acaricidal effect based on LC 50 of either essential oils or monoterpenoids against the mite was time dependant. The LC 50 values were decreased by increasing of exposure time. Clove, matrecary, chenopodium, rosemary, eucalyptus and caraway oils were shown to have high activity. As for the monoterpenoids, cinnamaldehyde and chlorothymol were found to be the most effective followed by citronellol. This study suggests the use of the essential oils and their major constituents as ecofriendly biodegradable agents for the control of house dust mite, D. pteronyssinus. PMID:17111463

  9. Detail of lift wire rope attachment to lift span at ...

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

    Detail of lift wire rope attachment to lift span at southeast corner. Note rope-adjustment turnbuckle with strap keepers to prevent its rotation, which could pull the bridge out of alignment. A single rope and light-gauge attachment at each corner were adequate for lifting the span because most of its weight was balanced by the two counterweights. - Potomac Edison Company, Chesapeake & Ohio Canal Bridge, Spanning C & O Canal South of U.S. 11, Williamsport, Washington County, MD

  10. Mite-control activities of active constituents isolated from Pelargonium graveolens against house dust mites.

    PubMed

    Jeon, Ju-Hyun; Kim, Hyung-Wook; Kim, Min-Gi; Lee, Hoi-Seon

    2008-10-01

    The mite-control activities of materials obtained from Pelargonium graveolens oil against Dermatophagoides farinae and D. pteronyssinus were examined using an impregnated fabric disk bioassay and were compared with those shown by commercial benzyl benzoate and N,N-diethylm- toluamide (DEET). Purification of the biologically active constituents from P. graveolens oil was done by silica gel chromatography and high performance liquid chromatography. The structures of the active components were analyzed by EI/MS, (1)H-NMR, (13)C-NMR, (1)H-(13)C COSYNMR, and DEPT-NMR spectra, and were identified as geraniol (C(10)H(18)O, MW 154.25, trans-3,7-dimethyl-2,6- octadien-1-ol) and beta-citronellol (C(10)H(20)O, MW 156.27, 3,7-dimethyl-6-octen-1-ol). Based on the LD50 values, the most toxic compound was geraniol (0.26 microg/cm(2)), followed by beta-citronellol (0.28 microg/cm(2)), benzyl benzoate (10.03 microg/ cm(2)), and DEET (37.12 microg/cm(2)) against D. farinae. In the case of D. pteronyssinus, geraniol (0.28 microg/cm(2)) was the most toxic, followed by beta-citronellol (0.29 microg/cm(2)), benzyl benzoate (9.58 microg/cm(2)), and DEET (18.23 microg/cm(2)). These results suggest that D. farinae and D. pteronyssinus may be controlled more effectively by the application of geraniol and beta-citronellol than benzyl benzoate and DEET. Furthermore, geraniol and beta-citronellol isolated from P. graveolens could be useful for managing populations of D. farinae and D. pteronyssinus.

  11. Observational support for dust grain emission by electrostatic forces

    NASA Astrophysics Data System (ADS)

    Silen, Johan; Hilchenbach, Martin; Hornung, Klaus; Merouane, Sihane; Schulz, Rita

    2015-04-01

    Dust collected close to the comet 67P by the COSIMA instrument, indicates that fluffy grains up to sizes of several 100 um are lifted off the comet surface and transported to the instrument substrate several tens of kilometers away. The temperature of the surface and the detected gas densities are too low to properly explain lifting grains from the cometary surface. We investigate grain dynamics using electrostatic forces. Comet surface lighting conditions create small scale multi pole electric fields by photons. These fields create forces on both charged and neutral dust grains and may serve as "active regions". The forces acting on the grain, scale as D3 with grain size and therefore large grains are proportionally simpler to elevate, provided the mass is not increasing at the same rate. The fluffy structure of the grains seem to fulfill this requirement. The limiting factor of this mechanism is set by the tensile strength of the grains. If the electrostatic force created exceeds the tensile strength, the grain will disintegrate through Coulomb explosion. The mechanism would favor lifting large fluffy grains off the surface because they have a capability of most easily creating mobile charges which interact in a favorable manner with the multi pole fields. Because of the conglomerate nature of the grains, a splitting of a grain may trigger a Coulomb explosion setting free the bulk dust distribution of small grains detected. The measured elongated impacts also suggest that disintegration is taking place close to the spacecraft. This would also be supported by the proposed model as the space craft charging represents a small scale field anomaly where grain splitting could become enhanced. The observed grains seem to fulfill all requirements of this tentative model.

  12. Plunger lift comes of age

    SciTech Connect

    Christian, J.; Lea, J.F.; Bishop, B.

    1995-11-01

    In the never-ending search to cut production costs while maintaining output and maximizing profits, operators are giving plunger lift a closer look. This is particularly true for marginal wells that might otherwise be shut in. Plunger lift is a cost-efficient method of artificially lifting low-liquid-volume oil wells that increase their profits. Some wells would have to be shut in if they remained on beam lit, due to high costs. With the plunger lift system, they are profitable. Field studies show plunger lift to be a cost-efficient, low-maintenance method of sustaining or improving output from low-volume wells. Not all wells are good candidates, so proper evaluation is essential. This paper reviews the optimal well environment for plunger lifts, their design, and cost benefit analysis.

  13. Selection of artificial lift method

    SciTech Connect

    Neely, B.; Gipson, F.; Clegg, J.; Capps, B.; Wilson, P.

    1981-01-01

    This paper summarizes the opening remarks of the panel members on a panel discussion of 'Selection of Artificial Lift Method' held at the 56th annual Fall Technical Conference and Exhibition of the Society of Petroleum Engineers of AIME in San Antonio, Texas, October 5-7, 1981. The topics discussed include: (1) reservoir and well considerations involved in artificial lift design; (2) sucker rod pumping; (3) gas lift; (4) submersible pumping; and, (5) hydraulic pumping. Advantages and limitations of each lift method are considered.

  14. Tobacco alkaloids and tobacco-specific nitrosamines in dust from homes of smokeless tobacco users, active smokers, and nontobacco users.

    PubMed

    Whitehead, Todd P; Havel, Christopher; Metayer, Catherine; Benowitz, Neal L; Jacob, Peyton

    2015-05-18

    Smokeless tobacco products, such as moist snuff or chewing tobacco, contain many of the same carcinogens as tobacco smoke; however, the impact on children of indirect exposure to tobacco constituents via parental smokeless tobacco use is unknown. As part of the California Childhood Leukemia Study, dust samples were collected from 6 homes occupied by smokeless tobacco users, 6 homes occupied by active smokers, and 20 tobacco-free homes. To assess children's potential for exposure to tobacco constituents, vacuum-dust concentrations of five tobacco-specific nitrosamines, including N'-nitrosonornicotine [NNN] and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone [NNK], as well as six tobacco alkaloids, including nicotine and myosmine, were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). We used generalized estimating equations derived from a multivariable marginal model to compare levels of tobacco constituents between groups, after adjusting for a history of parental smoking, income, home construction date, and mother's age and race/ethnicity. The ratio of myosmine/nicotine was used as a novel indicator of the source of tobacco contamination, distinguishing between smokeless tobacco products and tobacco smoke. Median dust concentrations of NNN and NNK were significantly greater in homes with smokeless tobacco users compared to tobacco-free homes. In multivariable models, concentrations of NNN and NNK were 4.8- and 6.9-fold higher, respectively, in homes with smokeless tobacco users compared to tobacco-free homes. Median myosmine/nicotine ratios were lower in homes with smokeless tobacco users (1.8%) compared to homes of active smokers (7.7%), confirming that cigarette smoke was not the predominant source of tobacco constituents in homes with smokeless tobacco users. Children living with smokeless tobacco users may be exposed to carcinogenic tobacco-specific nitrosamines via contact with contaminated dust and household surfaces.

  15. Sensorimotor Memory Biases Weight Perception During Object Lifting.

    PubMed

    van Polanen, Vonne; Davare, Marco

    2015-01-01

    When lifting an object, the brain uses visual cues and an internal object representation to predict its weight and scale fingertip forces accordingly. Once available, tactile information is rapidly integrated to update the weight prediction and refine the internal object representation. If visual cues cannot be used to predict weight, force planning relies on implicit knowledge acquired from recent lifting experience, termed sensorimotor memory. Here, we investigated whether perception of weight is similarly biased according to previous lifting experience and how this is related to force scaling. Participants grasped and lifted series of light or heavy objects in a semi-randomized order and estimated their weights. As expected, we found that forces were scaled based on previous lifts (sensorimotor memory) and these effects increased depending on the length of recent lifting experience. Importantly, perceptual weight estimates were also influenced by the preceding lift, resulting in lower estimations after a heavy lift compared to a light one. In addition, weight estimations were negatively correlated with the magnitude of planned force parameters. This perceptual bias was only found if the current lift was light, but not heavy since the magnitude of sensorimotor memory effects had, according to Weber's law, relatively less impact on heavy compared to light objects. A control experiment tested the importance of active lifting in mediating these perceptual changes and showed that when weights are passively applied on the hand, no effect of previous sensory experience is found on perception. These results highlight how fast learning of novel object lifting dynamics can shape weight perception and demonstrate a tight link between action planning and perception control. If predictive force scaling and actual object weight do not match, the online motor corrections, rapidly implemented to downscale forces, will also downscale weight estimation in a proportional manner.

  16. AFC-Enabled Simplified High-Lift System Integration Study

    NASA Technical Reports Server (NTRS)

    Hartwich, Peter M.; Dickey, Eric D.; Sclafani, Anthony J.; Camacho, Peter; Gonzales, Antonio B.; Lawson, Edward L.; Mairs, Ron Y.; Shmilovich, Arvin

    2014-01-01

    The primary objective of this trade study report is to explore the potential of using Active Flow Control (AFC) for achieving lighter and mechanically simpler high-lift systems for transonic commercial transport aircraft. This assessment was conducted in four steps. First, based on the Common Research Model (CRM) outer mold line (OML) definition, two high-lift concepts were developed. One concept, representative of current production-type commercial transonic transports, features leading edge slats and slotted trailing edge flaps with Fowler motion. The other CRM-based design relies on drooped leading edges and simply hinged trailing edge flaps for high-lift generation. The relative high-lift performance of these two high-lift CRM variants is established using Computational Fluid Dynamics (CFD) solutions to the Reynolds-Averaged Navier-Stokes (RANS) equations for steady flow. These CFD assessments identify the high-lift performance that needs to be recovered through AFC to have the CRM variant with the lighter and mechanically simpler high-lift system match the performance of the conventional high-lift system. Conceptual design integration studies for the AFC-enhanced high-lift systems were conducted with a NASA Environmentally Responsible Aircraft (ERA) reference configuration, the so-called ERA-0003 concept. These design trades identify AFC performance targets that need to be met to produce economically feasible ERA-0003-like concepts with lighter and mechanically simpler high-lift designs that match the performance of conventional high-lift systems. Finally, technical challenges are identified associated with the application of AFC-enabled highlift systems to modern transonic commercial transports for future technology maturation efforts.

  17. Sensorimotor Memory Biases Weight Perception During Object Lifting

    PubMed Central

    van Polanen, Vonne; Davare, Marco

    2015-01-01

    When lifting an object, the brain uses visual cues and an internal object representation to predict its weight and scale fingertip forces accordingly. Once available, tactile information is rapidly integrated to update the weight prediction and refine the internal object representation. If visual cues cannot be used to predict weight, force planning relies on implicit knowledge acquired from recent lifting experience, termed sensorimotor memory. Here, we investigated whether perception of weight is similarly biased according to previous lifting experience and how this is related to force scaling. Participants grasped and lifted series of light or heavy objects in a semi-randomized order and estimated their weights. As expected, we found that forces were scaled based on previous lifts (sensorimotor memory) and these effects increased depending on the length of recent lifting experience. Importantly, perceptual weight estimates were also influenced by the preceding lift, resulting in lower estimations after a heavy lift compared to a light one. In addition, weight estimations were negatively correlated with the magnitude of planned force parameters. This perceptual bias was only found if the current lift was light, but not heavy since the magnitude of sensorimotor memory effects had, according to Weber’s law, relatively less impact on heavy compared to light objects. A control experiment tested the importance of active lifting in mediating these perceptual changes and showed that when weights are passively applied on the hand, no effect of previous sensory experience is found on perception. These results highlight how fast learning of novel object lifting dynamics can shape weight perception and demonstrate a tight link between action planning and perception control. If predictive force scaling and actual object weight do not match, the online motor corrections, rapidly implemented to downscale forces, will also downscale weight estimation in a proportional manner

  18. Dust Assimilation in a Martian Global Climate Model

    NASA Astrophysics Data System (ADS)

    Ruan, Tao; Montabone, Luca; Read, Peter; Lewis, Stephen

    2013-04-01

    With spacecraft, including Mars Global Surveyor (MGS), Odyssey and Mars Reconnaissance Orbiter (MRO), in orbit about Mars in sequence since 1997, there are now measurements of atmospheric temperature and dust extending over nearly 7 Martian years with unprecedented spatial coverage. Although those observations have greatly developed our understanding of the evolution, structure and climate of the Red Planet, the intermittent nature of the measurements still limits our ability to study the full details of the circulation, especially relating to dust activity. A numerical model, on the other hand, can provide continuous simulated data with high temporal and spatial resolutions, but typically fails to produce some significant features of dust storms, as well as their interannual variability. In this context, we make use of data assimilation into a Martian Global Climate Model (MGCM). This approach is able to provide a complete, four-dimensional solution consistent with both observations and with physical constraints and balances represented by the numerical model. The MGCM we use combines a spectral dynamical solver, a tracer transport scheme and dust lifting routines developed in the UK and the Laboratoire de Météorologie Dynamique (LMD; Paris, France) Mars GCM physics package, developed in collaboration with Oxford, The Open University and Instituto de Astrofisica de Andalucia (Granada, Spain). Previous attempts at data assimilation for Mars have been conducted without explicitly advecting a dust tracer field, mainly because the Mars Global Surveyor/Thermal Emission Spectrometer (MGS/TES) did not provide information on the dust distribution in the vertical direction. The newly-available Mars Climate Sounder (MCS) data, however, provides relatively detailed information in the vertical direction, and accordingly here we describe a new data assimilation scheme with full assimilation of both temperature and dust measurements. The resulting assimilated reanalysis is

  19. Mineral magnetism of atmospheric dust over southwest coast of India: Impact of anthropogenic activities and implications to public health

    NASA Astrophysics Data System (ADS)

    Warrier, Anish Kumar; Shankar, R.; Manjunatha, B. R.; Harshavardhana, B. G.

    2014-03-01

    We have used rock magnetic techniques in this study to assess atmospheric pollution at five stations in and around Mangalore city on the southwestern coast of India. Samples of dust were collected from two suburban areas (Thokkottu and Pumpwell located respectively ~ 10 km and 3 km from the city center), the city center itself (Milagres) and industrial/port areas (Panambur and Mangalore Refinery and Petrochemicals Limited (MRPL)). Low-frequency magnetic susceptibility (χlf), frequency-dependent susceptibility (χfd), susceptibility of anhysteretic remanent magnetization (χARM) and isothermal remanent magnetization (IRM 20 to 1000 mT) were determined on 23 dust samples and inter-parametric ratios calculated. Results show that samples from suburban areas (particularly Thokkottu) are characterized by low χlf (< 314.1 × 10- 8 m3 kg- 1) and up to 6% χfd, suggesting low levels of pollution and the presence of pedogenic magnetite possibly derived from soils by wind erosion. However, the average χlf of Milagres, Panambur and MRPL dust samples is high by factors of 9.2, 3.3 and 2.6 compared to that of the Thokkottu sample. The Milagres sample contains magnetically "soft" minerals like magnetite, possibly indicating its derivation from motor vehicle exhaust. In contrast, the Panambur dust sample is characterized by magnetically "hard" minerals such as hematite and goethite as it has an 8-fold higher HIRM value compared to the Thokkottu sample. This magnetic signature is perhaps the result of dust particles derived from the grinding of hematite-rich iron ore by the Kudremukh Iron Ore Company Limited (KIOCL) at Panambur and its storage and export through the nearby New Mangalore Port. However, the dust sample from MRPL has magnetically "soft" minerals like magnetite. This magnetic mineral may have originated from petroleum refining processes at MRPL. Particulate pollution from industrial activities and motor vehicle exhaust is a threat to human health and is known to

  20. Dust Detector

    NASA Technical Reports Server (NTRS)

    Kelley, M. C.

    2001-01-01

    We discuss a recent sounding rocket experiment which found charged dust in the Earth's tropical mesosphere. The dust detector was designed to measure small (5000 - 10000 amu.) charged dust particles, most likely of meteoric origin. A 5 km thick layer of positively charged dust was found at an altitude of 90 km, in the vicinity of an observed sporadic sodium layer and sporadic E layer. The observed dust was positively charged in the bulk of the dust layer, but was negatively charged near the bottom.

  1. 77 FR 12080 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Cotton Dust...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-28

    ... Register on October 5, 2011 (76 FR 61752). Interested parties are encouraged to send comments to the OMB...; Cotton Dust Standard ACTION: Notice. SUMMARY: The Department of Labor (DOL) is submitting the Occupational Safety and Health Administration sponsored information collection request (ICR) titled,...

  2. Interplanetary dust - Trace element analysis of individual particles by neutron activation

    NASA Technical Reports Server (NTRS)

    Ganapathy, R.; Brownlee, D. E.

    1979-01-01

    Although micrometeorites of cometary origin are thought to be the dominant component of interplanetary dust, it has never been possible to positively identify such micrometer-sized particles. Two such particles have been identified as definitely micrometeorites since their abundances of volatile and nonvolatile trace elements closely match those of primitive solar system material.

  3. Activation of the components of an explosion using sorption on the surface of coal dust

    SciTech Connect

    Iskhakov, K.A.; Egoshin, V.V.; Zaostrovskii, A.N.

    2006-05-15

    The components of an explosion are under consideration. It is established that methane, hydrogen, oxygen and water steams, when sorbing on surface of coal dust, generate ion-radical forms. These forms promote fast chain-type reactions; mineral constituents of coals and fusinite group ingredients perform a role of catalysts.

  4. Aryl hydrocarbon receptor mediated activities in road dust from a metropolitan area, Hanoi-Vietnam: contribution of polycyclic aromatic hydrocarbons (PAHs) and human risk assessment.

    PubMed

    Tuyen, Le Huu; Tue, Nguyen Minh; Suzuki, Go; Misaki, Kentaro; Viet, Pham Hung; Takahashi, Shin; Tanabe, Shinsuke

    2014-09-01

    Dioxin-Responsive Chemical-Activated LUciferase gene eXpression assay (DR-CALUX) was applied to assess the total toxic activity of the mixture of PAHs and related compounds as well as dioxin-related compounds in road dust from urban areas of Hanoi, Vietnam. Road dust from Hanoi contained significantly higher DR-CALUX activities (3 to 39, mean 20 ng CALUX-TEQ/g dw) than those from a rural site (2 to 13, mean 5 ng CALUX-TEQ/g dw). The total concentrations of 24 major PAHs (Σ24PAHs) in urban road dust (0.1 to 5.5, mean 2.5 μg/g dw) were also 6 times higher than those in rural road dust (0.08 to 1.5, mean 0.4 μg/g dw). Diagnostic ratios of PAHs indicated vehicular engine combustion as the major PAH emission source in both sites. PAHs accounted for 0.8 to 60% (mean 10%) and 2 to 76% (mean 20%) of the measured CALUX-TEQs in road dust for Hanoi the rural site, respectively. Benzo[b]-/benzo[k]fluoranthenes were the major TEQ contributors among PAHs, whereas DRCs contributed <0.1% to CALUX-TEQs for both rural and urban sites. These results suggest TEQ contribution of other aryl hydrocarbon receptor agonists in road dust. Significant PAH concentrations in urban dust indicated high mutagenic and carcinogenic potencies. Estimated results of incremental life time cancer risk (ILCR) indicated that Vietnamese populations, especially those in urban areas such as Hanoi, are potentially exposed to high cancer risk via both dust ingestion and dermal contact. This is the first study on the exposure risk of AhR agonists, including PAHs and DRCs, in urban road dust from a developing country using a combined bio-chemical analytical approach.

  5. Dust Charging and Transport on Surfaces

    SciTech Connect

    Wang, X.; Robertson, S.; Horanyi, M.

    2011-11-29

    In this paper, we review laboratory studies of dust transport on surfaces in plasmas, performed for a number of different mechanisms: 1) Dust particles were levitated in plasma sheaths by electrostatic forces balancing the gravitational force. 2) Dust was observed to spread over and lift off a surface that repels electrons in a plasma. 3) Dust was transported on surfaces having different secondary electron yields in plasma with an electron beam as a consequence of differential charging. 4) We also report a mechanism of dust transport by electric fields occurring at electron beam impact/shadow boundaries. These processes are candidates to explain the formation of dust ponds that were recently observed in craters on the asteroid Eros by the NEAR Shoemaker spacecraft.

  6. Dust observations at orbital altitudes surrounding Mars.

    PubMed

    Andersson, L; Weber, T D; Malaspina, D; Crary, F; Ergun, R E; Delory, G T; Fowler, C M; Morooka, M W; McEnulty, T; Eriksson, A I; Andrews, D J; Horanyi, M; Collette, A; Yelle, R; Jakosky, B M

    2015-11-01

    Dust is common close to the martian surface, but no known process can lift appreciable concentrations of particles to altitudes above ~150 kilometers. We present observations of dust at altitudes ranging from 150 to above 1000 kilometers by the Langmuir Probe and Wave instrument on the Mars Atmosphere and Volatile Evolution spacecraft. Based on its distribution, we interpret this dust to be interplanetary in origin. A comparison with laboratory measurements indicates that the dust grain size ranges from 1 to 12 micrometers, assuming a typical grain velocity of ~18 kilometers per second. These direct observations of dust entering the martian atmosphere improve our understanding of the sources, sinks, and transport of interplanetary dust throughout the inner solar system and the associated impacts on Mars's atmosphere.

  7. Dust observations at orbital altitudes surrounding Mars.

    PubMed

    Andersson, L; Weber, T D; Malaspina, D; Crary, F; Ergun, R E; Delory, G T; Fowler, C M; Morooka, M W; McEnulty, T; Eriksson, A I; Andrews, D J; Horanyi, M; Collette, A; Yelle, R; Jakosky, B M

    2015-11-01

    Dust is common close to the martian surface, but no known process can lift appreciable concentrations of particles to altitudes above ~150 kilometers. We present observations of dust at altitudes ranging from 150 to above 1000 kilometers by the Langmuir Probe and Wave instrument on the Mars Atmosphere and Volatile Evolution spacecraft. Based on its distribution, we interpret this dust to be interplanetary in origin. A comparison with laboratory measurements indicates that the dust grain size ranges from 1 to 12 micrometers, assuming a typical grain velocity of ~18 kilometers per second. These direct observations of dust entering the martian atmosphere improve our understanding of the sources, sinks, and transport of interplanetary dust throughout the inner solar system and the associated impacts on Mars's atmosphere. PMID:26542578

  8. Operational Dust Prediction

    NASA Technical Reports Server (NTRS)

    Benedetti, Angela; Baldasano, Jose M.; Basart, Sara; Benincasa, Francesco; Boucher, Olivier; Brooks, Malcolm E.; Chen, Jen-Ping; Colarco, Peter R.; Gong, Sunlin; Huneeus, Nicolas; Jones, Luke; Lu, Sarah; Menut, Laurent; Morcrette, Jean-Jacques; Mulcahy, Jane; Nickovic, Slobodan; Garcia-Pando, Carlos P.; Reid, Jeffrey S.; Sekiyama, Thomas T.; Tanaka, Taichu Y.; Terradellas, Enric; Westphal, Douglas L.; Zhang, Xiao-Ye; Zhou, Chun-Hong

    2014-01-01

    Over the last few years, numerical prediction of dust aerosol concentration has become prominent at several research and operational weather centres due to growing interest from diverse stakeholders, such as solar energy plant managers, health professionals, aviation and military authorities and policymakers. Dust prediction in numerical weather prediction-type models faces a number of challenges owing to the complexity of the system. At the centre of the problem is the vast range of scales required to fully account for all of the physical processes related to dust. Another limiting factor is the paucity of suitable dust observations available for model, evaluation and assimilation. This chapter discusses in detail numerical prediction of dust with examples from systems that are currently providing dust forecasts in near real-time or are part of international efforts to establish daily provision of dust forecasts based on multi-model ensembles. The various models are introduced and described along with an overview on the importance of dust prediction activities and a historical perspective. Assimilation and evaluation aspects in dust prediction are also discussed.

  9. THE ROLE OF THE ACCRETION DISK, DUST, AND JETS IN THE IR EMISSION OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Mason, R. E.; Ramos Almeida, C.; Alonso-Herrero, A.

    2013-11-10

    We use recent high-resolution infrared (IR; 1-20 μm) photometry to examine the origin of the IR emission in low-luminosity active galactic nuclei (LLAGN). The data are compared with published model fits that describe the spectral energy distribution (SED) of LLAGN in terms of an advection-dominated accretion flow, truncated thin accretion disk, and jet. The truncated disk in these models is usually not luminous enough to explain the observed IR emission, and in all cases its spectral shape is much narrower than the broad IR peaks in the data. Synchrotron radiation from the jet appears to be important in very radio-loud nuclei, but the detection of strong silicate emission features in many objects indicates that dust must also contribute. We investigate this point by fitting the IR SED of NGC 3998 using dusty torus and optically thin (τ{sub mid-IR} ∼ 1) dust shell models. While more detailed modeling is necessary, these initial results suggest that dust may account for the nuclear mid-IR emission of many LLAGN.

  10. What is a safe lift?

    PubMed

    Espinoza, Kathy

    2013-09-01

    In a perfect world, a "safe" lift would be 51 pounds if the object is within 7 inches from the front of the body, if it is at waist height, if it is directly in front of the person, if there is a handle on the object, and if the load inside the box/bucket doesn't shift once lifted. If the load to be lifted does not meet all of these criteria, then it is an unsafe lift, and modifications must be made. Modifications would include lightening the load, getting help, or using a mechanical lifting device. There is always a way to turn an unsafe lift into a safer lift. An excellent resource for anyone interested in eliminating some of the hazards associated with lifting is the "Easy Ergonomics" publication from Cal/OSHA. This booklet offers practical advice on how to improve the workplace using engineering and administrative controls, problem-solving strategies and solutions, and a vast amount of ergonomics information and resources. "Easy Ergonomics" can be obtained by calling Cal/OSHA's education and training unit in Sacramento at 800-963-9424. A free copy can be obtained via www.dir.ca.gov/dosh/puborder.asp.

  11. Project LIFT: Year 1 Report

    ERIC Educational Resources Information Center

    Norton, Michael; Piccinino, Kelly

    2014-01-01

    Research for Action (RFA) is currently in the second year of a five-year external evaluation of the Project Leadership and Investment for Transformation (LIFT) Initiative in the Charlotte-Mecklenburg School District (CMS). Project LIFT is a public-private partnership between CMS and the local philanthropic and business communities in Charlotte,…

  12. A GENERALIZED POWER-LAW DIAGNOSTIC FOR INFRARED GALAXIES AT z > 1: ACTIVE GALACTIC NUCLEI AND HOT INTERSTELLAR DUST

    SciTech Connect

    Caputi, K. I.

    2013-05-10

    I present a generalized power-law (PL) diagnostic which allows one to identify the presence of active galactic nuclei (AGNs) in infrared (IR) galaxies at z > 1, down to flux densities at which the extragalactic IR background is mostly resolved. I derive this diagnostic from the analysis of 174 galaxies with S{sub {nu}}(24 {mu}m)>80 {mu}Jy and spectroscopic redshifts z{sub spec} > 1 in the Chandra Deep Field South, for which I study the rest-frame UV/optical/near-IR spectral energy distributions (SEDs), after subtracting a hot-dust, PL component with three possible spectral indices {alpha} = 1.3, 2.0, and 3.0. I obtain that 35% of these 24 {mu}m sources are power-law composite galaxies (PLCGs), which I define as those galaxies for which the SED fitting with stellar templates, without any previous PL subtraction, can be rejected with >2{sigma} confidence. Subtracting the PL component from the PLCG SEDs produces stellar mass correction factors <1.5 in >80% of cases. The PLCG incidence is especially high (47%) at 1.0 < z < 1.5. To unveil which PLCGs host AGNs, I conduct a combined analysis of 4 Ms X-ray data, galaxy morphologies, and a graybody modeling of the hot dust. I find that (1) 77% of all the X-ray AGNs in my 24 {mu}m sample at 1.0 < z < 1.5 are recognized by the PLCG criterion; (2) PLCGs with {alpha} = 1.3 or 2.0 have regular morphologies and T{sub dust} {approx}> 1000 K, indicating nuclear activity. Instead, PLCGs with {alpha} = 3.0 are characterized by disturbed galaxy dynamics, and a hot interstellar medium can explain their dust temperatures T{sub dust} {approx} 700-800 K. Overall, my results indicate that the fraction of AGNs among 24 {mu}m sources is between {approx}30% and 52% at 1.0 < z < 1.5.

  13. What's happening in artificial lift

    SciTech Connect

    Lea, J.F. ); Winkler, H.W.

    1991-05-01

    New developments reported this year are primarily in the areas of electrical submersible pumps (ESPs), beam pumps, and gas lift. The available information includes new products, techniques for extending run life, controllers, monitors and various other products. Specific topics in this article include: ESP turn key leases for temporary lifting; Horizontal pumps; Gas diffusion coatings for ESP bushings and sleeves; ESP variable rate current-voltage recording monitor; Power tubing ESP status; Low volume, high efficiency ESP stage; ESP improvements for horizontal and abrasive conditions; ESP computer design program effort; Well analyzer; Beam pump controller with variable frequency drive; Hydraulic pumping units; Mobile swab unit for marginal wells; Device for unseating downhole pumps; Gas lift valve test stand; Plunger lift controllers; Resettable ESP packer; Power generation from wellhead gas; and Artificial lift PC design program.

  14. Dust Storm

    Atmospheric Science Data Center

    2013-04-16

    article title:  Massive Dust Storm over Australia     View ... at JPL September 22, 2009 - Massive dust storm over Australia. project:  MISR category:  ... Sep 22, 2009 Images:  Dust Storm location:  Australia and New Zealand ...

  15. Dust activities near the dawn terminator on 67P/Churyumov-Gerasimenko observed by Rosetta/OSIRIS

    NASA Astrophysics Data System (ADS)

    Shi, Xian; Hu, Xuanyu; Sierks, Holger; Kührt, Ekkehard; Güttler, Carsten; Knollenberg, Jörg; Oklay, Nilda

    2016-04-01

    High-resolution images obtained by the OSIRIS camera on board Rosetta spacecraft have revealed dust activities happening close to terminators on the nucleus of comet 67P/Churyumov-Gerasimenko. While activities observed beyond dusk terminator in the night side are considered being sustained by subsurface thermal lag [1], those observed by the dawn terminator might be connected to the sublimation of water ice accumulated on the surface through re-condensation process during night [2,3]. In this study we present pre-perihelion observations of dust emission observed shortly after local sunrise. We investigate the location of these activities as well as their relation with local topography. A generic thermal-physical model will be applied to examine the feasibility of re-condensed ice on the surface being the source of such activities. [1] Shi, X., Hu, X., Sierks, H. et al., 2015, Sunset jets observed on comet 67P/Churyumov-Gerasimenko sustained by subsurface thermal lag, A&A, accepted. [2] Prialnik, D., A'Hearn, M. F., & Meech, K. J., 2008, A mechanism for short-lived cometary outbursts at sunrise as observed by Deep Impact on 9P/Tempel 1, MNRAS, 388, L20. [3] De Sanctis, M. C., Capaccioni, F., Ciarniello, M. et al., 2015, The diurnal cycle of water ice on comet 67P/Churyumov-Gerasimenko, Nature, 525, 500-503.

  16. Infrared spectra of obscuring dust tori around active galactic nuclei. I - Calculational method and basic trends

    NASA Technical Reports Server (NTRS)

    Pier, Edward A.; Krolik, Julian H.

    1992-01-01

    Using a new 2D radiative transfer algorithm, we have calculated the thermally reradiated infrared spectra of the compact dust tori which are thought to surround many AGN. These tori radiate anisotropically. Face-on tori may be from one-half to a few orders of magnitude brighter than edge-on tori throughout the infrared. Their spectra at nearly all viewing angles are basically 'bumps' which are about 50 percent wider than blackbodies and peak in the mid-infrared at a wavelength determined mainly by the flux of nuclear radiation on the inner edge of the torus. The infrared color temperatures are hotter for face-on tori than edge-on tori by about 100 K. The 10 micron silicate feature often associated with dust can appear in absorption, emission, or not at all. There is a rough tendency for absorption features to be more prominent for edge-on tori than for face-on tori.

  17. Weather and Large-Scale Dust Activity during Martian Northern Spring and Summer

    NASA Astrophysics Data System (ADS)

    Kass, David M.; Kleinboehl, Armin; McCleese, Daniel J.; Schofield, John Tim; Smith, Michael D.; Heavens, Nicholas

    2016-10-01

    Observations from MCS, TES and THEMIS now span the northern spring and summer seasons (Ls 0° to 180°) of 10 consecutive Mars Years (MY 24 through MY 33). These observations show very similar behavior each year. However, there are also noticeable differences and clear signs of inter-annual variability. To best study the three datasets, we examine zonal mean observations of the lower atmosphere (50 Pa, or ~25 km). This region was selected to provide the best quality from all three instruments. We separate the daytime (afternoon) and nighttime (early morning) data in the analysis.The climate at these seasons is dominated by the aphelion cloud belt, and 50 Pa is often close to the peak opacities in the clouds. There is also a strong diurnal thermal tide signature throughout the season at this altitude. The overall behavior is a rapid cooling at the start of the year (as the dust from the dusty season sediments out of the atmosphere) over the the first ~30° of Ls. The coldest temperatures then last until about the solstice and are followed by a slow warming trend through most of the rest of the season. The last ~30° prior to the fall equinox show a more rapid warming trend and significant inter-annual variability. In about half of the years, there is a warming event of the 50 Pa temperatures in the second half of northern summer. The warming is the signature of dust being lofted above the boundary layer, into the lower atmosphere. Due to the relatively clear atmosphere overall, even modest amounts of dust will create noticeable temperature changes. The temperature signature of the dust is more pronounced in the northern hemisphere.

  18. Summary of Lift and Lift/Cruise Fan Powered Lift Concept Technology

    NASA Technical Reports Server (NTRS)

    Cook, Woodrow L.

    1993-01-01

    A summary is presented of some of the lift and lift/cruise fan technology including fan performance, fan stall, ground effects, ingestion and thrust loss, design tradeoffs and integration, control effectiveness and several other areas related to vertical short takeoff and landing (V/STOL) aircraft conceptual design. The various subjects addressed, while not necessarily pertinent to specific short takeoff/vertical landing (STOVL) supersonic designs being considered, are of interest to the general field of lift and lift/cruise fan aircraft designs and may be of importance in the future. The various wind tunnel and static tests reviewed are: (1) the Doak VZ-4 ducted fan, (2) the 0.57 scale model of the Bell X-22 ducted fan aircraft, (3) the Avrocar, (4) the General Electric lift/cruise fan, (5) the vertical short takeoff and landing (V/STOL) lift engine configurations related to ingestion and consequent thrust loss, (6) the XV-5 and other fan-in-wing stall consideration, (7) hybrid configurations such as lift fan and lift/cruise fan or engines, and (8) the various conceptual design studies by air-frame contractors. Other design integration problems related to small and large V/STOL transport aircraft are summarized including lessons learned during more recent conceptual design studies related to a small executive V/STOL transport aircraft.

  19. Refined AFC-Enabled High-Lift System Integration Study

    NASA Technical Reports Server (NTRS)

    Hartwich, Peter M.; Shmilovich, Arvin; Lacy, Douglas S.; Dickey, Eric D.; Scalafani, Anthony J.; Sundaram, P.; Yadlin, Yoram

    2016-01-01

    A prior trade study established the effectiveness of using Active Flow Control (AFC) for reducing the mechanical complexities associated with a modern high-lift system without sacrificing aerodynamic performance at low-speed flight conditions representative of takeoff and landing. The current technical report expands on this prior work in two ways: (1) a refined conventional high-lift system based on the NASA Common Research Model (CRM) is presented that is more representative of modern commercial transport aircraft in terms of stall characteristics and maximum Lift/Drag (L/D) ratios at takeoff and landing-approach flight conditions; and (2) the design trade space for AFC-enabled high-lift systems is expanded to explore a wider range of options for improving their efficiency. The refined conventional high-lift CRM (HL-CRM) concept features leading edge slats and slotted trailing edge flaps with Fowler motion. For the current AFC-enhanced high lift system trade study, the refined conventional high-lift system is simplified by substituting simply-hinged trailing edge flaps for the slotted single-element flaps with Fowler motion. The high-lift performance of these two high-lift CRM variants is established using Computational Fluid Dynamics (CFD) solutions to the Reynolds-Averaged Navier-Stokes (RANS) equations. These CFD assessments identify the high-lift performance that needs to be recovered through AFC to have the CRM variant with the lighter and mechanically simpler high-lift system match the performance of the conventional high-lift system. In parallel to the conventional high-lift concept development, parametric studies using CFD guided the development of an effective and efficient AFC-enabled simplified high-lift system. This included parametric trailing edge flap geometry studies addressing the effects of flap chord length and flap deflection. As for the AFC implementation, scaling effects (i.e., wind-tunnel versus full-scale flight conditions) are addressed

  20. Dust Devil Populations and Statistics

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.; Jackson, Brian K.

    2016-08-01

    The highly-skewed diameter and pressure drop distributions of dust devils on Earth and Mars are noted, and challenges of presenting and comparing different types of observations are discussed. The widely-held view that Martian dust devils are larger than Earth's is critically assessed: the question is confounded somewhat by different observation techniques, but some indication of a {˜} 3x larger population on Mars is determined. The largest and most intense (in a relative pressure sense) devils recorded are on Mars, although the largest reported number density is on Earth. The difficulties of concepts used in the literature of `average' diameter, pressure cross section, and area fraction are noted in the context of estimating population-integral effects such as dust lifting.

  1. Orbit-Spin Coupling Accelerations and the 2007 Global-Scale Dust Storm on Mars

    NASA Astrophysics Data System (ADS)

    Shirley, James H.; Mischna, Michael A.

    2016-10-01

    Global-scale dust storms (GDS) occasionally occur during the southern summer season on Mars. The most recent such storm occurred in 2007 (Mars year 28). We employ a modified version of the MarsWRF global circulation model to simulate atmospheric conditions on Mars leading up to this event. Accelerations due to orbit-spin coupling (arxiv.org/abs/1605.02707) have been incorporated within the dynamical core of the MarsWRF GCM (arxiv.org/abs/1602.09137). We have previously documented an "intensification" of the large scale circulation (as represented in the GCM) due to these accelerations during the dust storm season of MY 28. In this presentation we look more closely at the differences between GCM outcomes for runs performed both with and without the "coupling term accelerations" for this important year. The current version of the GCM has a number of shortcomings; most significantly, we do not yet include radiatively active dust within our simulations. The GCM thus cannot replicate the rapid warming and inflation of the atmosphere that occurs soon after significant dust lifting has commenced; and we do not address specific mechanisms of dust lifting. Nonetheless our model outcomes provide some insight into phenomena such as the variability of global wind systems during intervals leading up to the inception of the global storm. The phasing and amplitude of the orbit-spin coupling accelerations (arxiv.org/abs/1605.01452) for the current Mars year (MY 33) are in some ways similar to those calculated for MY 28. Thus we will also examine and describe MarsWRF model outcomes for the current dust storm season.

  2. Lifting strength in two-person teamwork.

    PubMed

    Lee, Tzu-Hsien

    2016-01-01

    This study examined the effects of lifting range, hand-to-toe distance, and lifting direction on single-person lifting strengths and two-person teamwork lifting strengths. Six healthy males and seven healthy females participated in this study. Two-person teamwork lifting strengths were examined in both strength-matched and strength-unmatched groups. Our results showed that lifting strength significantly decreased with increasing lifting range or hand-to-toe distance. However, lifting strengths were not affected by lifting direction. Teamwork lifting strength did not conform to the law of additivity for both strength-matched and strength-unmatched groups. In general, teamwork lifting strength was dictated by the weaker of the two members, implying that weaker members might be exposed to a higher potential danger in teamwork exertions. To avoid such overexertion in teamwork, members with significantly different strength ability should not be assigned to the same team.

  3. Comparison of Infant Car Seat grip orientations and lift strategies.

    PubMed

    Clamann, Michael; Zhu, Biwen; Beaver, Leah; Taylor, Kinley; Kaber, David

    2012-07-01

    The rear-facing Infant Car Seat (ICS) is designed to meet federal requirements for transporting children less than 1 year old. Typical use includes transfer in and out of a vehicle, which is shown to be a difficult lift. Despite the frequency of this lift, manufacturers provide little guidance for users. Review of relevant literature suggested an ICS featuring an angled handle, promoting a neutral wrist posture, would increase grip stability and decrease lifting effort. Popular press suggested a foot-in-car stance for the ICS lift would do the same. An experiment was conducted in which wrist deviations from neutral posture were recorded along with lifting muscle activation levels (multiple flexor muscles and biceps brachii) and overall perceived exertion for straight versus a new bent handle design and conventional stance versus foot-in-car. Foot position was examined to test the recommendations in the popular press. Surprisingly, wrist deviation was not significantly affected by the new bent handle design (due to compensatory behavior with the straight handle) but was related to foot placement (p=0.04). Results revealed the bent handle to significantly reduce flexor activation compared with the straight handle (p=0.0003); however, the level of biceps activation increased. Biceps activation also significantly increased for foot-in-car stance (p=0.035) but not flexor activation. In general, the bent handle enabled the user to lift the ICS with a steadier grip and less effort.

  4. Heavy Lift Launch Vehicle Concept

    NASA Technical Reports Server (NTRS)

    2004-01-01

    During the Space Shuttle development phase, Marshall plarners concluded a Heavy Lift Launch Vehicle (HLLV) would be needed for successful Space Industrialization. Shown here in this 1976's artist's conception is an early version of the HLLV during launch.

  5. Impact-Mobilized Dust in the Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Nemtchinov, I. V.; Shuvalov, V. V.; Greeley, R.

    2002-01-01

    We consider dust production and entrainment into the atmosphere of Mars by impacts. Numerical simulations based on the multidimensional multimaterial hydrocode were conducted for impactors 1 to 100 m in size and velocities 11 and 20 kilometers per second. The size distribution of particles was based on experimentrr wing TNT explosions. Dust can be mobilized even when the impactor does not reach the ground through the release of energy in the atmosphere, We found that the blast produced winds entrained dust by a mechanism similar to boundary layer winds as determined from the wind-tunnel tests. For a l-m radius stony asteroid releasing its energy in the atmosphere the lifted mass of dust is larger than that in a typical dust devil and could trigger local dust storms, For a 100-m-radius meteoroid the amount of injected dust is comparable with the tota! mass of a global dust storm.

  6. Face lift postoperative recovery.

    PubMed

    Mottura, A Aldo

    2002-01-01

    The purpose of this paper is to describe what I have studied and experienced, mainly regarding the control and prediction of the postoperative edema; how to achieve an agreeable recovery and give positive support to the patient, who in turn will receive pleasant sensations that neutralize the negative consequences of the surgery.After the skin is lifted, the drainage flow to the flaps is reversed abruptly toward the medial part of the face, where the flap bases are located. The thickness and extension of the flap determines the magnitude of the post-op edema, which is also augmented by medial surgeries (blepharo, rhino) whose trauma obstruct their natural drainage, increasing the congestion and edema. To study the lymphatic drainage, the day before an extended face lift (FL) a woman was infiltrated in the cheek skin with lynfofast (solution of tecmesio) and the absorption was observed by gamma camera. Seven days after the FL she underwent the same study; we observed no absorption by the lymphatic, concluding that a week after surgery, the lymphatic network was still damaged. To study the venous return during surgery, a fine catheter was introduced into the external jugular vein up to the mandibular border to measure the peripheral pressure. Following platysma plication the pressure rose, and again after a simple bandage, but with an elastic bandage it increased even further, diminishing considerably when it was released. Hence, platysma plication and the elastic bandage on the neck augment the venous congestion of the face. There are diseases that produce and can prolong the surgical edema: cardiac, hepatic, and renal insufficiencies, hypothyroidism, malnutrition, etc. According to these factors, the post-op edema can be predicted, the surgeon can choose between a wide dissection or a medial surgery, depending on the social or employment compromises the patient has, or the patient must accept a prolonged recovery if a complex surgery is necessary. Operative

  7. Protoplanetary Dust

    NASA Astrophysics Data System (ADS)

    Apai, Dániel; Lauretta, Dante S.

    2010-01-01

    Preface; 1. Planet formation and protoplanetary dust Daniel Apai and Dante Lauretta; 2. The origins of protoplanetary dust and the formation of accretion disks Hans-Peter Gail and Peter Hope; 3. Evolution of protoplanetary disk structures Fred Ciesla and Cornelius P. Dullemond; 4. Chemical and isotopic evolution of the solar nebula and protoplanetary disks Dmitry Semenov, Subrata Chakraborty and Mark Thiemens; 5. Laboratory studies of simple dust analogs in astrophysical environments John R. Brucato and Joseph A. Nuth III; 6. Dust composition in protoplanetaty dust Michiel Min and George Flynn; 7. Dust particle size evolution Klaus M. Pontoppidan and Adrian J. Brearly; 8. Thermal processing in protoplanetary nebulae Daniel Apai, Harold C. Connolly Jr. and Dante S. Lauretta; 9. The clearing of protoplanetary disks and of the protosolar nebula Ilaira Pascucci and Shogo Tachibana; 10. Accretion of planetesimals and the formation of rocky planets John E. Chambers, David O'Brien and Andrew M. Davis; Appendixes; Glossary; Index.

  8. Protoplanetary Dust

    NASA Astrophysics Data System (ADS)

    Apai, D.´niel; Lauretta, Dante S.

    2014-02-01

    Preface; 1. Planet formation and protoplanetary dust Daniel Apai and Dante Lauretta; 2. The origins of protoplanetary dust and the formation of accretion disks Hans-Peter Gail and Peter Hope; 3. Evolution of protoplanetary disk structures Fred Ciesla and Cornelius P. Dullemond; 4. Chemical and isotopic evolution of the solar nebula and protoplanetary disks Dmitry Semenov, Subrata Chakraborty and Mark Thiemens; 5. Laboratory studies of simple dust analogs in astrophysical environments John R. Brucato and Joseph A. Nuth III; 6. Dust composition in protoplanetaty dust Michiel Min and George Flynn; 7. Dust particle size evolution Klaus M. Pontoppidan and Adrian J. Brearly; 8. Thermal processing in protoplanetary nebulae Daniel Apai, Harold C. Connolly Jr. and Dante S. Lauretta; 9. The clearing of protoplanetary disks and of the protosolar nebula Ilaira Pascucci and Shogo Tachibana; 10. Accretion of planetesimals and the formation of rocky planets John E. Chambers, David O'Brien and Andrew M. Davis; Appendixes; Glossary; Index.

  9. Lift enhancement in flying snakes

    NASA Astrophysics Data System (ADS)

    Krishnan, Anush; Socha, John; Vlachos, Pavlos; Barba, Lorena

    2013-11-01

    Flying snakes use a unique method of aerial locomotion: they jump from tree branches, flatten their bodies and undulate through the air to produce a glide. The shape of their body cross-section during the glide plays an important role in generating lift. We present a computational investigation of the aerodynamics of the cross-sectional shape. We performed two-dimensional simulations of incompressible flow past the anatomically correct cross-section of the species Chrysopelea paradisi, which show that a significant enhancement in lift appears at an angle of attack of 35 degrees, for Reynolds numbers 2000 and above. Previous experiments on physical models also demonstrated an increased lift and at the same angle of attack. The simulations point to the lift enhancement arising from the early separation of the boundary layer on the dorsal surface of the snake profile, without stall. The separated shear layer rolls up and interacts with secondary vorticity in the near-wake, inducing the primary vortex to remain closer to the body and thus cause enhanced suction, resulting in higher lift. In physical experiments, the flow is inherently 3-D due to fluid instabilities, and it is intriguing that the enhanced lift also appears in the two-dimensional simulations.

  10. Intergalactic Dust

    NASA Astrophysics Data System (ADS)

    Li, A.

    2002-12-01

    We study the composition and sizes of intergalactic dust based on the expulsion of interstellar dust from the galactic disk. Interstellar grains in the Galactic disk are modelled as a mixture of amorphous silicate dust and carbonaceous dust consisting of polycyclic aromatic hydrocarbon (PAH) molecules and larger graphitic grains (Li & Draine 2001) with size distributions like those of the Milky Way dust (Weingartner & Draine 2001). We model their dynamic evolution in terms of the collective effects caused by (1) radiative acceleration, (2) gravitational attraction, (3) gas drag, (4) thermal sputtering, and (5) Lorenz force from the galactic magnetic field (Ferrara et al. 1991). Radiation pressure from the stellar disk exerts an upward force on dust grains and may ultimately expel them out of the entire galaxy. Gravitational force from the stellar, dust and gas disk as well as the dark matter halo exerts a downward force. Thermal sputtering erodes all grains to some degree but more efficiently destroys small grains. This, together with the fact that (1) very small grains (with small radiation pressure efficiencies) are not well coupled to starlight; (2) for large grains the radiative force to the gravitational force is approximately inversely proportional to grain size, acts as a size ``filter'' for dust leaking into the intergalactic space. Since the radiation pressure efficiency and the grain destruction rate are sensitive to dust composition, the relative importance of carbon dust compared to silicate dust expelled into the intergalactic space differs from that in the galactic plane. We derive the size distributions of both silicate and carbonaceous dust finally getting into the intergalactic space and obtain an intergalactic extinction curve. The predicted intergalactic infrared emission spectrum is calculated. References: Ferrara, A., Ferrini, F., Franco, J., & Barsella, B. 1991, ApJ, 381, 137 Li, A., & Draine, B.T. 2001, ApJ, 554, 778 Weingartner, J

  11. Dust storms: recent developments.

    PubMed

    Goudie, Andrew S

    2009-01-01

    Dust storms have a number of impacts upon the environment including radiative forcing, and biogeochemical cycling. They transport material over many thousands of kilometres. They also have a range of impacts on humans, not least on human health. In recent years the identification of source areas for dust storms has been an important area or research, with the Sahara (especially Bodélé) and western China being recognised as the strongest sources globally. Another major development has been the recognition of the degree to which dust storm activity has varied at a range of time scales, millennial, century, decadal, annual and seasonal.

  12. Induction factor optimization through variable lift control

    NASA Astrophysics Data System (ADS)

    Cooney, John; Corke, Thomas; Nelson, Robert; Williams, Theodore

    2011-11-01

    Due to practical design limitations coupled with the detrimental effects posed by complex wind regimes, modern wind turbines struggle to maintain or even reach ideal operational states. With additional gains through traditional approaches becoming more difficult and costly, active lift control represents a more attractive option for future designs. Here, plasma actuators have been explored experimentally in trailing edge applications for use in attached flow regimes. This authority would be used to drive the axial induction factor toward the ideal given by the Betz limit through distributed lift control thereby enhancing energy capture. Predictions of power improvement achievable by this methodology are made with blade - element momentum theory but will eventually be demonstrated in the field at the Laboratory for Enhanced Wind Energy Design, currently under construction at the University of Notre Dame.

  13. Changes in Activities of Respiratory Enzymes in Lungs of Guinea-pigs Exposed to Silica Dust: II. Comparison of the Effects of Quartz Dust and Lampblack on the Succinate Oxidase System

    PubMed Central

    Breyer, Maria G.; Kilroe-Smith, T. A.; Prinsloo, H.

    1964-01-01

    Kilroe-Smith and Breyer (1963) reported that in the early stages of silicosis in guinea-pigs exposed to the inhalation of quartz dust, before the formation of collagen, there were increases in the specific activities of the complete succinate oxidase system and succinate dehydrogenase. The effects on these enzymes of quartz dust have now been compared with the effects of the fibrogenically `inert' lampblack. Lampblack causes a slight increase in the specific activities of these enzymes but the effects are small compared to those caused by quartz. Lampblack also causes a much smaller increase in lung weight than quartz, thus the enzyme increases are roughly parallel to the rise in lung weight. It appears that the effects observed on the enzymes are part of the general pattern associated with the early stages of the development of silicosis. PMID:14106132

  14. Understanding the Transport of Patagonian Dust and Its Influence on Marine Biological Activity in the South Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Johnson, Matthew; Meskhidze, Nicholas; Kiliyanpilakkil, Praju; Gasso, Santiago

    2010-01-01

    Modeling and remote sensing techniques were applied to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of soluble-iron- laden mineral dust deposition on marine primary productivity in the South Atlantic Ocean (SAO) surface waters. The global chemistry transport model GEOS-Chem, implemented with an iron dissolution scheme, was applied to evaluate the atmospheric transport and deposition of mineral dust and bioavailable iron during two dust outbreaks originating in the source regions of Patagonia. In addition to this "rapidly released" iron, offline calculations were also carried out to estimate the amount of bioavailable iron leached during the residence time of dust in the ocean mixed layer. Model simulations showed that the horizontal and vertical transport pathways of Patagonian dust plumes were largely influenced by the synoptic meteorological patterns of high and low pressure systems. Model-predicted horizontal and vertical transport pathways of Patagonian dust over the SAO were in reasonable agreement with remotely-sensed data. Comparison between remotely-sensed and offline calculated ocean surface chlorophyll-a concentrations indicated that, for the two dust outbreaks examined in this study, the deposition of bioavailable iron in the SAO through atmospheric pathways was insignificant. As the two dust transport episodes examined here represent typical outflows of mineral dust from South American sources, our study suggests that the atmospheric deposition of mineral dust is unlikely to induce large scale marine primary productivity and carbon sequestration in the South Atlantic sector of the Southern Ocean.

  15. Airborne Dust, "The Good Guy or the Bad Guy": How Much do We Know?

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee

    2010-01-01

    Processes in generating, transporting, and dissipating the airborne dust particles are global phenomena -African dust regularly reaching the Alps; Asian dust seasonally crossing the Pacific into North America, and ultimately the Atlantic into Europe. One of the vital biogeochemical roles dust storms play in Earth's ecosystem is routinely mobilizing mineral dust, as a source of iron, from deserts into oceans for fertilizing the growth of phytoplankton -the basis of the oceanic food chain. Similarly, these dust-laden airs also supply crucial nutrients for the soil of tropical rain forests, the so-called womb of life that hosts 50-90% of the species on Earth. With massive amounts of dust lifted from desert regions and injected into the atmosphere, however, these dust storms often affect daily activities in dramatic ways: pushing grit through windows and doors, forcing people to stay indoors, causing breathing problems, reducing visibility and delaying flights, and by and large creating chaos. Thus, both increasing and decreasing concentrations of doses result in harmful biological effects; so do the airborne dust particles to our Living Earth. Since 1997 NASA has been successfully launching a series of satellites - the Earth Observing System - to intensively study, and gain a better understanding of, the Earth as an integrated system. Through participation in many satellite remote-sensing/retrieval and validation projects over the years, we have gradually developed and refined the SMART (Surface-sensing Measurements for Atmospheric Radiative Transfer) and COMMIT (Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile observatories, a suite of surface remote sensing and in-situ instruments that proved to be vital in providing high temporal measurements, which complement the satellite observations. In this talk, we will present SMART-COMMIT which has played key roles, serving as network or supersite, in major international research projects such

  16. Synoptic conditions favouring the occurrence of dust transport from Africa toward Sardinia Island.

    NASA Astrophysics Data System (ADS)

    Canu, Annalisa; Pellizzaro, Grazia; Pintus, Gabriella; Duce, Pierpaolo

    2016-04-01

    Dust events that reach Italy have usually origin in the Sahara and Sahel regions (north-western part of Africa), which represent the dust sources nearest to Italy. In those regions the dust-lifting activity occurs in a remarkable way. Every dust event is different from the others; in fact dust transport and dust concentration in the air can vary remarkably depending on the synoptic situation. In Sardinia, dust events are more frequent in the May-November period, but they can also take place in the December-April period. The main aim of this work was to describe dust outbreaks in Sardinia and to identify the main meteorological scenarios that originate the transport of dust towards the central and western Mediterranean Basin. The evaluation of the geographical dispersion of Saharan dust was performed by using MODIS satellite data and Meteosat imagery combined with SKIRON forecasting model. The origin and the trajectory of the dust carried by winds towards Italy were inferred by the NOAA HYSPLIT model (Hybrid Single Particle Lagrangian Integrated Trajectory Model). In addition, PM10 (particulate matter with a diameter of less than 10 μm) and meteorological data registered by the ARPAS (Regional Environmental Protection Agency of Sardinia) monitoring stations were used to highlight the arrival of African air masses in Sardinia. The study was carried out during the 2014. A total of five events occurred during the year (two in spring and three in autumn) were analyzed. The origin of air masses loaded with dust from North Africa was confirmed by satellite imagery and 3-days air mass backward trajectories calculated by the NOAA HYSPLIT model. The analysis of the PM10 daily pattern registered at northern and southern Sardinia sites showed a rising of values during the dust event. The arrival of air masses from Africa caused the daily mean air temperature to rise whereas relative humidity values decreased. Finally, the results showed that all the event analyzed were

  17. Lifted turbulent jet flames

    NASA Astrophysics Data System (ADS)

    Hammer, Jay A.

    Experiments were conducted on lifted, turbulent jet diffusion flames. An automated technique using a linear photodiode array was implemented to measure the temporal history of the liftoff height h. The measurements enabled accurate determination of the mean liftoff height [...] under a wide range of flow conditions, including several fuels, nozzle diameters, and exit velocities [...]. The results showed an approximately linear relationship between [...] and [...], with a slight dependence on Reynolds number. A strain-rate model for liftoff, based on far-field scaling of turbulent jets, provides an explanation for the linear dependence of [...] on [...]. Measurements were also made in which the nozzle fluid contained varying amounts of air, where it was found that the slope of the [...] vs. [...] line increases faster than predicted by far-field scaling of turbulent jets. The discrepancy is attributed to near-field effects.The amplitudes of the fluctuations in h were found to be of the order of the local large scale of the jet. There is a slight increase in normalized fluctuation level [...] with [...], and there is some variation of [...] with fuel type. The time scales of the fluctuations of h were found to be considerably longer than the local large-scale time of the turbulence [...]. By using fuels of different chemical times to vary [...], the measured correlation time [...] normalized by [...] was found to collapse with Richardson number [...]. Experiments in which the nozzles were oriented horizontally showed no change in [...], however. Additional experiments were conducted to investigate alternative explanations for the variation of [...] with [...]. These experiments included measuring the flame length L simultaneously with h, and measuring the visible radiation I simultaneously with h. L(t) was found to be nearly uncorrelated with h(t), dismissing the possibility that a feedback mechanism from L to h controls the fluctuations of h. Although I(t) is highly

  18. Metal dusting

    SciTech Connect

    Edited by K. Natesan

    2004-01-01

    This workshop was held soon after the September 11th incident under a climate of sorrow and uncertainty among the people of the world, in particular the Workshop participants and their host organizations. With considerable help from the partiicpants, the Workshop was conducted as planed and we had excellent participation in spite of the circumstances. A good fraction of the attendees in the Workshop were from abroad and from several industries, indicating the importance and relevance of the subject for the chemical process industry. Degradation of structural metallic alloys by metal dusting has been an issue for over 40 years in the chemical, petrochemical, syngas, and iron ore reduction plants. However, the fundamental scientific reasons for the degradation of complex alloys in high carbon activity environments are not clear. one of the major parameters of importance is the variation in gas chemistry in both the laboratory experiments and in the plant-service environments. the industry has questioned the applicability of the laboratory test data, obtained in low steam environments, in assessment and life prediction for the materials in plant service where the environments contain 25-35% steam. Several other variables such as system pressure, gas flow velocity, incubation time, alloy chemistry, surface finish, and weldments, were also identified in the literature as to having an effect on the initiatino and propagation of metal dusting attack. It is the purpose of this Workshop to establish a forum in which the researchers from scientific and industrial laboratories, alloy manufacturers, end users, and research and development sponsors can exchange information, discuss different points of view, prioritize the issues, and to elaborate on the trends in industry for the future. We believe that we accomplished these goals successfully and sincerely thank the participants for their contributions.

  19. Numerical Prediction of Dust. Chapter 10

    NASA Technical Reports Server (NTRS)

    Benedetti, Angela; Baldasano, J. M.; Basart, S.; Benincasa, F.; Boucher, O.; Brooks, M.; Chen, J. P.; Colarco, P. R.; Gong, S.; Huneeus, N.; Jones, L; Lu, S.; Menut, L.; Mulcahy, J.; Nickovic, S.; Morcrette, J.-J.; Perez, C.; Reid, J. S.; Sekiyama, T. T.; Tanaka, T.; Terradellas, E.; Westphal, D. L.; Zhang, X.-Y.; Zhou, C.-H.

    2013-01-01

    Covers the whole breadth of mineral dust research, from a scientific perspective Presents interdisciplinary work including results from field campaigns, satellite observations, laboratory studies, computer modelling and theoretical studies Explores the role of dust as a player and recorder of environmental change This volume presents state-of-the-art research about mineral dust, including results from field campaigns, satellite observations, laboratory studies, computer modelling and theoretical studies. Dust research is a new, dynamic and fast-growing area of science and due to its multiple roles in the Earth system, dust has become a fascinating topic for many scientific disciplines. Aspects of dust research covered in this book reach from timescales of minutes (as with dust devils, cloud processes, and radiation) to millennia (as with loess formation and oceanic sediments), making dust both a player and recorder of environmental change. The book is structured in four main parts that explore characteristics of dust, the global dust cycle, impacts of dust on the Earth system, and dust as a climate indicator. The chapters in these parts provide a comprehensive, detailed overview of this highly interdisciplinary subject. The contributions presented here cover dust from source to sink and describe all the processes dust particles undergo while travelling through the atmosphere. Chapters explore how dust is lifted and transported, how it affects radiation, clouds, regional circulations, precipitation and chemical processes in the atmosphere, and how it deteriorates air quality. The book explores how dust is removed from the atmosphere by gravitational settling, turbulence or precipitation, how iron contained in dust fertilizes terrestrial and marine ecosystems, and about the role that dust plays in human health. We learn how dust is observed, simulated using computer models and forecast. The book also details the role of dust deposits for climate reconstructions

  20. China Dust

    Atmospheric Science Data Center

    2013-04-16

    ... SpectroRadiometer (MISR) nadir-camera images of eastern China compare a somewhat hazy summer view from July 9, 2000 (left) with a ... arid and sparsely vegetated surfaces of Mongolia and western China pick up large quantities of yellow dust. Airborne dust clouds from the ...

  1. Dust Storm

    Atmospheric Science Data Center

    2013-04-16

    ... April 11, 2004 (top panels) contrast strongly with the dust storm that swept across Iraq and Saudi Arabia on May 13, 2004 (bottom panels). ... Apr 11 and May 13, 2004 Images:  Dust Storm location:  Middle East thumbnail:  ...

  2. Mist lift analysis summary report

    SciTech Connect

    Davenport, R.L.

    1980-09-01

    The mist flow open-cycle OTEC concept proposed by S.L. Ridgway has much promise, but the fluid mechanics of the mist flow are not well understood. The creation of the mist and the possibility of droplet growth leading to rainout (when the vapor can no longer support the mist) are particularly troublesome. This report summarizes preliminary results of a numerical analysis initiated at SERI in FY79 to study the mist-lift process. The analysis emphasizes the mass transfer and fluid mechanics of the steady-state mist flow and is based on one-dimensional models of the mist flow developed for SERI by Graham Wallis. One of Wallis's models describes a mist composed of a single size of drops and another considers several drop sizes. The latter model, further developed at SERI, considers a changing spectrum of discrete drop sizes and incorporates the mathematics describing collisions and growth of the droplets by coalescence. The analysis results show that under conditions leading to maximum lift in the single-drop-size model, the multigroup model predicts significantly reduced lift because of the growth of droplets by coalescence. The predicted lift height is sensitive to variations in the mass flow rate and inlet pressure. Inclusion of a coasting section, in which the drops would rise ballistically without change in temperature, may lead to increased lift within the existing range of operation.

  3. Normalized lift: an energy interpretation of the lift coefficient simplifies comparisons of the lifting ability of rotating and flapping surfaces.

    PubMed

    Burgers, Phillip; Alexander, David E

    2012-01-01

    For a century, researchers have used the standard lift coefficient C(L) to evaluate the lift, L, generated by fixed wings over an area S against dynamic pressure, ½ρv(2), where v is the effective velocity of the wing. Because the lift coefficient was developed initially for fixed wings in steady flow, its application to other lifting systems requires either simplifying assumptions or complex adjustments as is the case for flapping wings and rotating cylinders.This paper interprets the standard lift coefficient of a fixed wing slightly differently, as the work exerted by the wing on the surrounding flow field (L/ρ·S), compared against the total kinetic energy required for generating said lift, ½v(2). This reinterpreted coefficient, the normalized lift, is derived from the work-energy theorem and compares the lifting capabilities of dissimilar lift systems on a similar energy footing. The normalized lift is the same as the standard lift coefficient for fixed wings, but differs for wings with more complex motions; it also accounts for such complex motions explicitly and without complex modifications or adjustments. We compare the normalized lift with the previously-reported values of lift coefficient for a rotating cylinder in Magnus effect, a bat during hovering and forward flight, and a hovering dipteran.The maximum standard lift coefficient for a fixed wing without flaps in steady flow is around 1.5, yet for a rotating cylinder it may exceed 9.0, a value that implies that a rotating cylinder generates nearly 6 times the maximum lift of a wing. The maximum normalized lift for a rotating cylinder is 1.5. We suggest that the normalized lift can be used to evaluate propellers, rotors, flapping wings of animals and micro air vehicles, and underwater thrust-generating fins in the same way the lift coefficient is currently used to evaluate fixed wings.

  4. Seasonally active frost-dust avalanches on a north polar scarp of Mars captured by HiRISE

    USGS Publications Warehouse

    Russell, P.; Thomas, N.; Byrne, S.; Herkenhoff, K.; Fishbaugh, K.; Bridges, N.; Okubo, C.; Milazzo, M.; Daubar, I.; Hansen, C.; McEwen, A.

    2008-01-01

    North-polar temporal monitoring by the High Resolution Imaging Science Experiment (HiRISE) orbiting Mars has discovered new, dramatic examples that Mars1 CO2-dominated seasonal volatile cycle is not limited to quiet deposition and sublimation of frost. In early northern martian spring, 2008, HiRISE captured several cases of CO2 frost and dust cascading down a steep, polar scarp in discrete clouds. Analysis of morphology and process reveals these events to be similar to terrestrial powder avalanches, sluffs, and falls of loose, dry snow. Potential material sources and initiating mechanisms are discussed in the context of the Martian polar spring environment and of additional, active, aeolian processes observed on the plateau above the scarp. The scarp events are identified as a trigger for mass wasting of bright, fractured layers within the basal unit, and may indirectly influence the retreat rate of steep polar scarps in competing ways. Copyright 2008 by the American Geophysical Union.

  5. DUST IN THE POLAR REGION AS A MAJOR CONTRIBUTOR TO THE INFRARED EMISSION OF ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Hoenig, S. F.; Antonucci, R.; Kishimoto, M.; Tristram, K. R. W.; Asmus, D.; Weigelt, G.; Prieto, M. A.; Gandhi, P.; Burtscher, L.; Duschl, W. J.

    2013-07-10

    Dust around active galactic nuclei (AGNs) is distributed over a wide range of spatial scales and can be observed in the infrared (IR). It is generally assumed that the distribution on parsec scales forms a geometrically and optically thick entity in the equatorial plane around the accretion disk and broad-line region-dubbed {sup d}ust torus{sup -}that emits the bulk of the subarcsecond-scale IR emission and gives rise to orientation-dependent obscuration. However, recent IR interferometry studies with unprecedented position angle (P.A.) and baseline coverage on these small scales in two obscured (type 2) AGNs have revealed that the majority of the mid-IR emission in these objects is elongated in the polar direction. These observations are difficult to reconcile with the standard interpretation that most of the parsec-scale mid-IR emission in AGNs originate from the torus and challenges the justification of using simple torus models to model the broadband IR emission. Here, we report detailed interferometry observations of the unobscured (type 1) AGN in NGC 3783 that allow us to constrain the size, elongation, and direction of the mid-IR emission with high accuracy. The mid-IR emission is characterized by a strong elongation toward position angle P.A. -52 Degree-Sign , closely aligned with the polar axis (P.A. -45 Degree-Sign ). We determine half-light radii along the major and minor axes at 12.5 {mu}m of (20.0 {+-} 3.0) mas Multiplication-Sign (6.7 {+-} 1.0) mas or (4.23 {+-} 0.63) pc Multiplication-Sign (1.42 {+-} 0.21) pc, which corresponds to intrinsically scaled sizes of (69.4 {+-} 10.8) r{sub in} Multiplication-Sign (23.3 {+-} 3.5) r{sub in} for the inner dust radius of r{sub in} = 0.061 pc as inferred from near-IR reverberation mapping. This implies an axis ratio of 3:1, with about 60%-90% of the 8-13 {mu}m emission associated with the polar-elongated component. It is quite likely that the hot-dust emission as recently resolved by near-IR interferometry is

  6. Pallet loading dust control system

    SciTech Connect

    Cecala, A.B.; Covelli, A.

    1987-01-01

    This paper presents a pallet loading dust control system designed to lower the dust exposure of workers during the bag stacking process at mineral processing facilities. The system makes bag stacking much easier because the pallet height remains constant throughout the entire bag stacking cycle through the use of a hydraulic lift table. The system uses a push-pull ventilation technique to capture the dust generated during bag stacking. A low-volume, high-velocity blower system operating at approximately 150 cfm blows a stream of air over the top layer of bags on the pallet. The blower system is composed of two 3-in air jets (approximately 1,200-ft/min velocity) directed toward an exhaust system on the opposite side of the pallet. As these air jets travel across the pallet, they entrain the dust generated during bag stacking. The exhaust ventilation system pulls approximately 2,500 cfm of air and dust through the exhaust hood. This exhaust air can then be dumped into a bag-house ventilation system, or filtered before being discharged outside the mill.

  7. Study of Electrical Activity in Martian Dust Storms with the Deep Space Network antennas

    NASA Astrophysics Data System (ADS)

    Martinez, S.; Kuiper, T. B. H.; Majid, W. A.; Garcia-Miro, C.; Tamppari, L. K.; Renno, N. O.; Ruf, C.; Trinh, J. T.

    2012-09-01

    Evidence for non-thermal emission produced by electrostatic discharges in a deep Martian dust storm has been reported by Ruf et al. 2009 [1]. Such discharges had been detected with an innovative kurtosis detector installed in a 34m radio telescope of the Deep Space Network (DSN) in June of 2006. The kurtosis (the fourth central moment of the signal normalized by the square of the second central moment) is extremely sensitive to the presence of non-thermal radiation, but is insensitive to variations in the intensity of the thermal radiation and instrument gain. The non-thermal radiation was detected while a 35 Km deep Martian dust storm was within the field of view of the radio telescope and presented signatures of modulation by the Martian Schumann Resonance. Encouraged by this discovery, several attempts have been made within the DSN to confirm the detection using the R&D antenna (DSS-13) and other antennas in the Madrid and Goldstone complexes, but using a very limited receiver, in terms of recorded data rates, the Very Long Baseline Interferometry (VLBI) Science Receiver (VSR). We are planning to initiate an extensive monitoring of Mars emission in a noninterfering basis while our antennas are tracking various Mars probes, using the Wideband Very Long Baseline Interferometry (VLBI) Science Receiver (WVSR). The WVSR is a very flexible open-loop digital backend that is used for radio science and spacecraft navigation support in the DSN. This instrument allows us to sample a larger bandwidth than with previously used detectors. The processing to look for the kurtosis signature will be performed in software, limited only by the computer capacity. Additionally there are plans to develop an even more powerful custom-built detector based in CASPER technology and Graphic Processing Units for enhance computational power. This contribution will describe how we plan to select the target Mars tracking passes from the DSN schedule. An automated process will generate

  8. Slug bucket lifting yoke analysis

    SciTech Connect

    McElfresh, A.J.

    1994-11-14

    There are baskets of fuel in the storage pools in the Purex facility (202-A). These baskets (called slug buckets) need to be removed from Purex and taken to the K-Basins. The current slug bucket lifting yoke is of sufficient age to be in question structurally. Therefore new yokes need to be fabricated. Prior to fabricating new yokes, the slug bucket lifting yoke DWG needs to be updated for fabrication. However, the design needs to be refined so that the yoke will be easier to fabricate. These calculations are prepared to demonstrate the adequacy of the new design. The objective of these calculations is to select appropriately sized structural members and weld sizes to serve as components in the slug bucket lifting yoke.

  9. Modeling Mars Cyclogenesis and Frontal Waves: Seasonal Variations and Implications on Dust Activity

    NASA Technical Reports Server (NTRS)

    Hollingsworth, J. L.; Kahre, M. A.

    2014-01-01

    Between late autumn through early spring,middle and high latitudes onMars exhibit strong equator-to-polemean temperature contrasts (i.e., "baroclinicity"). Data collected during the Viking era and observations from both the Mars Global Surveyor (MGS) and Mars Reconnaissance Orbiter (MRO) indicate that such strong baroclinicity supports vigorous, large-scale eastward traveling weather systems (i.e., transient synoptic period waves) [1, 2]. For a rapidly rotating, differentially heated, shallow atmosphere such as on Earth and Mars, these large-scale, extratropical weather disturbances are critical components of the global circulation. The wave-like disturbances serve as agents in the transport of heat and momentum between low and high latitudes of the planet. Through cyclonic/anticyclonic winds, intense shear deformations, contractions-dilatations in temperature and density, and sharp perturbations amongst atmospheric tracers (i.e., dust, volatiles (e.g., water vapor) and condensates (e.g., water-ice cloud particles)), Mars' extratropical weather systems have significant sub-synoptic scale ramifications by supporting atmospheric frontal waves (Fig. 1).

  10. Endoscopic brow lifts uber alles.

    PubMed

    Patel, Bhupendra C K

    2006-12-01

    Innumerable approaches to the ptotic brow and forehead have been described in the past. Over the last twenty-five years, we have used all these techniques in cosmetic and reconstructive patients. We have used the endoscopic brow lift technique since 1995. While no one technique is applicable to all patients, the endoscopic brow lift, with appropriate modifications for individual patients, can be used effectively for most patients with brow ptosis. We present the nuances of this technique and show several different fixation methods we have found useful.

  11. MicroMED: a dust particle counter for the characterization of airborne dust close to the surface of Mars

    NASA Astrophysics Data System (ADS)

    Cozzolino, Fabio; Esposito, Francesca; Molfese, Cesare; Cortecchia, Fausto; Saggin, Bortolino; D'amato, Francesco

    2015-04-01

    Monitoring of airborne dust is very important in planetary climatology. Indeed, dust absorbs and scatter solar and thermal radiation, severely affecting atmospheric thermal structure, balance and dynamics (in terms of circulations). Wind-driven blowing of sand and dust is also responsible for shaping planetary surfaces through the formation of sand dunes and ripples, the erosion of rocks, and the creation and transport of soil particles. Dust is permanently present in the atmosphere of Mars and its amount varies with seasons. During regional or global dust storms, more than 80% of the incoming sunlight is absorbed by dust causing an intense atmospheric heating. Airborne dust is therefore a crucial climate component on Mars which impacts atmospheric circulations at all scales. Main dust parameters influencing the atmosphere heating are size distribution, abundance, albedo, single scattering phase function, imaginary part of the index of refraction. Moreover, major improvements of Mars climate models require, in addition to the standard meteorological parameters, quantitative information about dust lifting, transport and removal mechanisms. In this context, two major quantities need to be measured for the dust source to be understood: surface flux and granulometry. While many observations have constrained the size distribution of the dust haze seen from the orbit, it is still not known what the primary airborne dust (e.g. the recently lifted dust) is made of, size-wise. MicroMED has been designed to fill this gap. It will measure the abundance and size distribution of dust, not in the atmospheric column, but close to the surface, where dust is lifted, so to be able to monitor dust injection into the atmosphere. This has never been performed in Mars and other planets exploration. MicroMED is an Optical Particle Counter, analyzing light scattered from single dust particles to measure their size and abundance. A proper fluid-dynamic system, including a pump and a

  12. Provisional Recommended Weight Limits for Manual Lifting During Pregnancy

    PubMed Central

    Waters, Thomas R.; MacDonald, Leslie A.; Hudock, Stephen D.; Goddard, Donald E.

    2015-01-01

    Objective The National Institute for Occupational Safety and Health (NIOSH) Revised Lifting Equation (RNLE) was adapted to derive recommended weight limits (RWLs) for pregnant workers and to develop corresponding guidelines for clinicians. Background In the past three decades there has been a large increase in the number of women employed outside the home and remaining in the workforce during pregnancy. Practical authoritative guidelines based on accumulated evidence are needed to inform allowable work activity levels for healthy pregnant workers. Method Empirically based lifting criteria established by NIOSH to reduce the risk of overexertion injuries in the general U.S. working population were evaluated for application to pregnant workers. Our evaluation included an extensive review of the literature linking occupational lifting to maternal and fetal health. Decision logic and supporting literature are presented, along with computational details. Results Provisional RWLs for pregnant workers were derived from the RNLE, along with guidelines for clinicians. The guidelines advise against pregnant workers lifting below midshin and overhead. Conclusion Based on our review of the available evidence, we present lifting thresholds that most pregnant workers with uncomplicated pregnancies should be able to perform without increased risk of adverse maternal and fetal health consequences. Except for restrictions involving lifting from the floor and overhead, the provisional guidelines presented are compatible with NIOSH lifting recommendations adopted in the early 1990s for the general working population. Application Implementation of these provisional guidelines could protect millions of female workers in the work-place from fetal and maternal lifting-related health problems. PMID:24669554

  13. Searching for ski-lift injury: an uphill struggle?

    PubMed

    Smartt, Pam; Chalmers, David

    2010-03-01

    Injuries arising from ski-lift malfunction are rare. Most arise from skier error when embarking or disembarking, or from improper lift operation. A search of the literature failed to uncover any studies focusing specifically on ski-lift injuries. The purpose of this study was to identify and characterise ski-lift injury resulting in hospitalisation and comment on barriers to reporting and reporting omissions. New Zealand hospitalised injury discharges 2000-2005 formed the primary dataset. To aid case identification these data were linked to ACC compensated claims for the same period and the data searched for all hospitalised cases of injury arising from ski-lifts. 44 cases were identified representing 2% of snow-skiing/snowboarding cases. 28 cases (64%) were male and 16 (36%) female, the average age was 32 yrs (range 5-73 yrs). The majority of cases were snow-skiers (35 cases, 80%). Most of the injuries were serious, or potentially so, with 1 case of traumatic pneumothorax, one of pulmonary embolism (after jumping from a ski-lift) and 28 cases sustaining fractures (six to the neck-of-femur, one to the lumbar spine and one to the pubis). ICISS scores for all cases ranged from 1.00 to 0.8182 (probability of dying in hospital 0-18.18%). Only 14 (32%) cases could be easily identified from ICD-10-AM e-codes and activity codes in the discharge summary. The ICD-10-AM external cause code for ski-lift injury V98 ("other specified transport accidents") was only assigned to 39% of cases. The type of ski-lift could only be determined in 24 cases (55%).

  14. The Role of African Easterly Wave on Dust Transport and the Interaction Between Saharan Dust Layer and Atlantic ITCZ During Boreal Summer

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Kim, Kyu-Myong

    2012-01-01

    In this paper, we investigate the relationships among Saharan dust outbreak and transport, African easterly waves (AEW), African easterly jet (AEJ) and associated convective activities of Atlantic Intertropical Convergence Zone (ITCZ) using Cloudsat-Calipso, MODIS and MERRA data. We find that a major Saharan dust outbreak is associated with the formation of a westward propagating strong cyclone around 15-25N over the western part northern Saharan. The strong cyclonic flow mobilizes and lifts the dust from the desert surface to a high elevation. As the cyclone propagate westward, it transports a thick elevated dust layer between 900 -500 hPa from the African continent to the eastern Atlantic. Cloudiness is reduced within the warm, dry dusty layer, but enhanced underneath it, possibly due to the presence of a shallow inversion layer over the marine boundary layer. The dust outbreak is linked to enhanced deep convection in the northern part of Atlantic ITCZ, abutting the southern flank of the dust layer, and a strengthening of the northward flank of the AEJ. As the dust layer spreads westward, it loses elevation and becomes increasing diffused as it reaches the central and western Atlantic. Using band pass filtered EOF analysis of MERRA winds, we find that AEWs propagating westward along two principal tracks, centered at 15-25N and 5-10N respectively. The easterly waves in the northern track are highly correlated with major dust outbreak over North Africa and associated with slower moving systems, with a quasi-periodicity of 6-9 day. On the other hand, easterly waves along the southern track are faster, with quasi-periodicity of 3-5 days. These faster easterly waves are closely tied to rainfall/cloud variations along the Atlantic ITCZ. Dust transport along the southern track by the faster waves generally leads rainfall/cloud anomalies in the same region by one or two days, suggesting the southern tracks of dust outbreak are regions of strong interaction between

  15. Proof-of-principle results for identifying the composition of dust particles and volcanic ash samples through the technique of photon activation analysis at the IAC

    NASA Astrophysics Data System (ADS)

    Mamtimin, Mayir; Cole, Philip L.; Segebade, Christian

    2013-04-01

    Instrumental analytical methods are preferable in studying sub-milligram quantities of airborne particulates collected in dust filters. The multi-step analytical procedure used in treating samples through chemical separation can be quite complicated. Further, due to the minute masses of the airborne particulates collected on filters, such chemical treatment can easily lead to significant levels of contamination. Radio-analytical techniques, and in particular, activation analysis methods offer a far cleaner alternative. Activation methods require minimal sample preparation and provide sufficient sensitivity for detecting the vast majority of the elements throughout the periodic table. In this paper, we will give a general overview of the technique of photon activation analysis. We will show that by activating dust particles with 10- to 30-MeV bremsstrahlung photons, we can ascertain their elemental composition. The samples are embedded in dust-collection filters and are irradiated "as is" by these photons. The radioactivity of the photonuclear reaction products is measured with appropriate spectrometers and the respective analytes are quantified using multi-component calibration materials. We shall provide specific examples of identifying the elemental components of airborne dust particles and volcanic ash by making use of bremsstrahlung photons from an electron linear accelerator at the Idaho Accelerator Center in Pocatello, Idaho.

  16. Dust Devils : How many, how big, and how deadly ?

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    2015-12-01

    Dust devils are significant agents of dust-lifting on Mars, but their importance on Earth has been debated. Accurate quantification of the amount of dust-lifting by devils on Earth requires an understanding of the population of devils (i.e. the formation rate of devils of different diameters as a function of meteorological conditions, their longevity and their dust-lifting intensity). Correlation among these parameters (e.g. large devils last longer) means great care must be taken in evaluating the population integral - the contribution of 'average' devils may be dwarfed by the few largest ones, but large area-time surveys are needed to detect the rare giants. Significant progress has been made in quantifying the vortex population in the field using new pressure-logging instrumentation to generate robust statistics which appear also consistent with Large Eddy Simulations, and the vortex population can be reconciled with visual dust devil counts using Monte Carlo modeling, where core pressure drop is a useful intensity metric, and a threshold of about 0.3 hPa corresponds to visible dust lifting. Further field measurements are exploring the parameter correlation, and vortex model-fitting is being use to estimate diameter and core pressure drop by combining pressure and wind speed/direction data at a single station, a technique that may be useful in the upcoming InSight mission at Mars, where dust devils may be a useful seismic source to probe the near-surface regolith structure. Array measurements with multiple stations are also yielding powerful results. The core pressure drop can also be related to the weight-loading of structures for the quantification of dust devils as a hazard. In fact, dust devils are responsible for a number of deaths on the ground (in addition to aircraft and parachuting accidents) which will be briefly reviewed.

  17. "Dust Devils": Gardening Agents on the Surface of Mars, and Hidden Hazards to Human Exploration?

    NASA Technical Reports Server (NTRS)

    Marshall, J.; Smith, P.; White, B.; Farrell, W.

    1999-01-01

    dust devils are to be expected in reasonable abundance. First, from a geological perspective, the vortices will act as "gardening" agents for the top few centimeters of entrainable material. Over time (hundreds of millions, or billions of years being available), they will cover the surface with scouring paths, and the grain sizes that can be lofted by a vortex probably extends over the whole sand to dust range. The depositional paths are, of course, much larger, so that vortex-induced deposition is more widespread than vortex-induced erosion, and will without doubt, affect the whole region in which the dust devils occur (this might explain why rocks at the Viking site seemed oddly capped with dust in a region apparently subject to general aeolian scouring). On Mars, the lift forces in dust devils might be less than on earth owing to the much thinner atmosphere, but this may be counterbalanced by lower gravity and greater vortex velocities. Certainly, when active, other aeolian phenomena on Mars --sand motion and dust storms, seem no less energetic and no less capable of lofting sediments than equivalent terrestrial aeolian phenomena. Every several years, within the current climatic regime, the surface of Mars is subject to light dust fall from global dust storms. Over time, this should develop a very uniform surface layer, with commensurate uniformity in grain size, mineralogy, albedo, color, and general spectroscopic properties. Dust devils will disturb this situation by continually mixing the surface dust with underlying layers, perhaps composed of silt and sand. This size mixing will also involve compositional mixing. After some years, the thin layer of dust that may be difficult to entrain alone, becomes progressively mixed with coarser materials that could reduce the general aeolian threshold of the soil. Certainly the continual disturbance by vorticity will prevent surface stabilization that may bind or indurate grains (caused by slow cementation or ice welding

  18. "Dust Devils": Gardening Agents on the Surface of Mars, and Hidden Hazards to Human Exploration?

    NASA Astrophysics Data System (ADS)

    Marshall, J.; Smith, P.; White, B.; Farrell, W.

    1999-09-01

    dust devils are to be expected in reasonable abundance. First, from a geological perspective, the vortices will act as "gardening" agents for the top few centimeters of entrainable material. Over time (hundreds of millions, or billions of years being available), they will cover the surface with scouring paths, and the grain sizes that can be lofted by a vortex probably extends over the whole sand to dust range. The depositional paths are, of course, much larger, so that vortex-induced deposition is more widespread than vortex-induced erosion, and will without doubt, affect the whole region in which the dust devils occur (this might explain why rocks at the Viking site seemed oddly capped with dust in a region apparently subject to general aeolian scouring). On Mars, the lift forces in dust devils might be less than on earth owing to the much thinner atmosphere, but this may be counterbalanced by lower gravity and greater vortex velocities. Certainly, when active, other aeolian phenomena on Mars --sand motion and dust storms, seem no less energetic and no less capable of lofting sediments than equivalent terrestrial aeolian phenomena. Every several years, within the current climatic regime, the surface of Mars is subject to light dust fall from global dust storms. Over time, this should develop a very uniform surface layer, with commensurate uniformity in grain size, mineralogy, albedo, color, and general spectroscopic properties. Dust devils will disturb this situation by continually mixing the surface dust with underlying layers, perhaps composed of silt and sand. This size mixing will also involve compositional mixing. After some years, the thin layer of dust that may be difficult to entrain alone, becomes progressively mixed with coarser materials that could reduce the general aeolian threshold of the soil. Certainly the continual disturbance by vorticity will prevent surface stabilization that may bind or indurate grains (caused by slow cementation or ice welding

  19. Near-surface meteorological conditions associated with active resuspension of dust by wind erosion

    SciTech Connect

    Hodgin, C.R.

    1982-01-01

    The meteorological conditions associated with extreme winds in the lee of the Colorado Rocky Mountains were studied from the viewpoint of dust resuspension and dispersion. Wind, dispersion, temperature, and dew point conditions occurring near the surface were discussed in detail for a selected event. Near-surface wind speeds were compared to observations made at a standard sampling height. These field data were developed to aid in validation and interpretation of wind tunnel observations and application of dispersion models to wind erosion resuspension. Three conclusions can immediately be drawn from this investigation. First, wind storms in nature are quite gusty, with gusts exceeding the mean speed by 50 percent or more. However, wind direction variations are small by comparison. Thus, wind tunnel studies should be able to simulate the large along-flow turbulence, while keeping cross-flow turbulence to a moderate level. This also has an application to the puff modeling of high winds. Puff models normally assume that the along-flow dispersion coefficient is equal to the cross-flow value. This study suggests that the along-flow coefficient should be much larger than its cross-flow counterpart. Another conclusion involves the usual assumption of Pasquill-Gifford stability class D. In the event studied here, the atmosphere was well mixed with near-neutral thermal stability, yet the horizontal dispersion stability class varied from G to A. Thus, an assumption of Class D horizontal dispersion during high winds would not have been valid during this case. A final conclusion involves the widely applied assumption of a logarithmic wind speed profile during high wind events. This study has indicated that such an assumption is appropriate.

  20. Sahara Dust

    Atmospheric Science Data Center

    2013-04-15

    article title:  Casting Light and Shadows on a Saharan Dust Storm   ... CA, for NASA's Science Mission Directorate, Washington, D.C. The Terra spacecraft is managed by NASA's Goddard Space Flight Center, ...

  1. Immersion freezing of supermicron mineral dust particles: freezing results, testing different schemes for describing ice nucleation, and ice nucleation active site densities.

    PubMed

    Wheeler, M J; Mason, R H; Steunenberg, K; Wagstaff, M; Chou, C; Bertram, A K

    2015-05-14

    Ice nucleation on mineral dust particles is known to be an important process in the atmosphere. To accurately implement ice nucleation on mineral dust particles in atmospheric simulations, a suitable theory or scheme is desirable to describe laboratory freezing data in atmospheric models. In the following, we investigated ice nucleation by supermicron mineral dust particles [kaolinite and Arizona Test Dust (ATD)] in the immersion mode. The median freezing temperature for ATD was measured to be approximately -30 °C compared with approximately -36 °C for kaolinite. The freezing results were then used to test four different schemes previously used to describe ice nucleation in atmospheric models. In terms of ability to fit the data (quantified by calculating the reduced chi-squared values), the following order was found for ATD (from best to worst): active site, pdf-α, deterministic, single-α. For kaolinite, the following order was found (from best to worst): active site, deterministic, pdf-α, single-α. The variation in the predicted median freezing temperature per decade change in the cooling rate for each of the schemes was also compared with experimental results from other studies. The deterministic model predicts the median freezing temperature to be independent of cooling rate, while experimental results show a weak dependence on cooling rate. The single-α, pdf-α, and active site schemes all agree with the experimental results within roughly a factor of 2. On the basis of our results and previous results where different schemes were tested, the active site scheme is recommended for describing the freezing of ATD and kaolinite particles. We also used our ice nucleation results to determine the ice nucleation active site (INAS) density for the supermicron dust particles tested. Using the data, we show that the INAS densities of supermicron kaolinite and ATD particles studied here are smaller than the INAS densities of submicron kaolinite and ATD particles

  2. Immersion freezing of supermicron mineral dust particles: freezing results, testing different schemes for describing ice nucleation, and ice nucleation active site densities.

    PubMed

    Wheeler, M J; Mason, R H; Steunenberg, K; Wagstaff, M; Chou, C; Bertram, A K

    2015-05-14

    Ice nucleation on mineral dust particles is known to be an important process in the atmosphere. To accurately implement ice nucleation on mineral dust particles in atmospheric simulations, a suitable theory or scheme is desirable to describe laboratory freezing data in atmospheric models. In the following, we investigated ice nucleation by supermicron mineral dust particles [kaolinite and Arizona Test Dust (ATD)] in the immersion mode. The median freezing temperature for ATD was measured to be approximately -30 °C compared with approximately -36 °C for kaolinite. The freezing results were then used to test four different schemes previously used to describe ice nucleation in atmospheric models. In terms of ability to fit the data (quantified by calculating the reduced chi-squared values), the following order was found for ATD (from best to worst): active site, pdf-α, deterministic, single-α. For kaolinite, the following order was found (from best to worst): active site, deterministic, pdf-α, single-α. The variation in the predicted median freezing temperature per decade change in the cooling rate for each of the schemes was also compared with experimental results from other studies. The deterministic model predicts the median freezing temperature to be independent of cooling rate, while experimental results show a weak dependence on cooling rate. The single-α, pdf-α, and active site schemes all agree with the experimental results within roughly a factor of 2. On the basis of our results and previous results where different schemes were tested, the active site scheme is recommended for describing the freezing of ATD and kaolinite particles. We also used our ice nucleation results to determine the ice nucleation active site (INAS) density for the supermicron dust particles tested. Using the data, we show that the INAS densities of supermicron kaolinite and ATD particles studied here are smaller than the INAS densities of submicron kaolinite and ATD particles

  3. Prosthetic Hand Lifts Heavy Loads

    NASA Technical Reports Server (NTRS)

    Carden, James R.; Norton, William; Belcher, Jewell G.; Vest, Thomas W.

    1991-01-01

    Prosthetic hand designed to enable amputee to lift diverse heavy objects like rocks and logs. Has simple serrated end effector with no moving parts. Prosthesis held on forearm by system of flexible straps. Features include ruggedness, simplicity, and relatively low cost.

  4. Experiments on dust transport in plasma to investigate the origin of the lunar horizon glow

    NASA Astrophysics Data System (ADS)

    Wang, X.; Horányi, M.; Robertson, S.

    2009-05-01

    Dust grains on the lunar surface are exposed to UV radiation and solar wind plasma and can collect electrical charges, leading to their possible lift-off and transport in the presence of near-surface electric fields. Motivated by the long-standing open questions about the physics of electrostatic lunar dust transport, we investigated the dynamics of dust grains on a conducting surface in a laboratory plasma. The dust used in these experiments was a nonconducting JSC-Mars-1 sample with particle size of less than 25 microns. We found that dust grains placed on a conducting surface, which is biased more negatively than its floating potential, charge positively, and an initial pile spreads to form a dust ring. Dust particles were observed to land on insulating blocks, indicating the height of their hopping motion. The measured electrostatic potential distribution above the dust pile shows that an outward pointing electric field near the edge of the pile is responsible for spreading the positively charged grains. A nonmonotonic potential dip was measured in the sheath above an insulating patch, indicating a localized upward electric field causing the dust lift-off from the surface. Faraday cup measurements showed that the grains near the boundary of the dust pile collect more charge than those closer to the center of the dust pile and can be more readily lifted and moved in the radial direction, leading to the formation of a spreading ring.

  5. Powered-Lift Aerodynamics and Acoustics. [conferences

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Powered lift technology is reviewed. Topics covered include: (1) high lift aerodynamics; (2) high speed and cruise aerodynamics; (3) acoustics; (4) propulsion aerodynamics and acoustics; (5) aerodynamic and acoustic loads; and (6) full-scale and flight research.

  6. Actively accumulating dust changes phosphorus abundance and fractionation in soils and tree foliage in a super-humid, high leaching environment, West Coast, New Zealand

    NASA Astrophysics Data System (ADS)

    Eger, A.; Almond, P. C.; Condron, L.; Turner, B. L.

    2011-12-01

    Pedogenesis in humid climates, as found in chronosequence studies, ultimately leads to nutrient depletion and enhanced formation of secondary, less plant-available forms of nutrients with progressing time. Deposition of mineral dust has been shown to be an important process to mitigate such depletion in soils and ecosystems (e.g. Hawaii, Amazon Basin). However, the magnitude of its effect has hardly been quantified and little is known about the accession pathways. This study exploits a unique geomorphic setting of a Holocene sequence of sand dune ridges. This sequence combines an active dust flux gradient along the dunes downwind of a braided riverbed and, distal from the dust source, a chronosequence across the dunes (170-6500 y). Pedogenesis is very rapid with Spodosols developing after 1000 y under a thick organic root mat. Comparison of soil and ecosystem phosphorus (P) across the chronosequence and along the dust gradient on the 6500 y dune allows us to quantify the capacity of active dust deposition to alter the P pool and to determine the biogeochemical pathways by which P fluxes are assimilated under super-humid, high leaching conditions. Across both gradients, we quantified the P concentrations in tree foliage and the P fractions in the upper 50 cm of the soils (total P, organic P, apatite P, occluded P, non-occluded P), including solution 31P NMR spectroscopy of organic P in selected profiles. Soil P across the chronosequence follows the P evolution model of Walker and Syers (1976) - a 75% decline of total P within 6500 y due to strong leaching losses of apatite P (82% loss) coinciding with an increase in secondary P forms. Along the dust gradient, increasing eolian deposition towards the river from ~1000 m distance is associated with a decline of apatite P and an increase of organic P. Foliar P mirrors the total P and apatite P decline of the soils across the chronosequence with a steep decrease after 1000 y. Along the dust gradient, foliar P correlates

  7. Cognitive attribution of the source of an error in object-lifting results in differences in motor generalization.

    PubMed

    Fercho, Kelene; Baugh, Lee A

    2016-09-01

    To lift an object, the motor system must predict the weight of the object and use this information to program appropriate lifting forces. If this prediction is erroneous, people may assign blame for the error to either themselves or an external source-a process called credit assignment. In the present study, we explored the role of credit assignment on weight predictions during a lifting task. Participants were told that the EMG surface electrodes attached to their lifting hand were either part of a "passive" system that recorded muscular activity, or part of an "active" system that would apply energy to the muscle, influencing weight perception. Participants performed 90 lifts of the training blocks, followed by 10 lifts of a newly encountered larger test block. In between training and test trials, the experimenter turned off the recording system and removed the surface electrodes for participants in the "active" group. For each lift, we determined the initial peak rate of change of vertical load force rate and load-phase duration, estimates of predicted object weight. Analysis of the first 10 training lifts and the last 10 training lifts revealed no effect of Active versus Passive EMG on weight predictions. However, after removing the EMG equipment, participants in the "active" group failed to scale their predictive load forces in the same manner as those in the "passive" condition when lifting a novel block. We conclude that cognitive information may play a role in credit assignment, influencing weight prediction when lifting novel objects.

  8. Shape memory alloy resetable spring lift for pedestrian protection

    NASA Astrophysics Data System (ADS)

    Barnes, Brian M.; Brei, Diann E.; Luntz, Jonathan E.; Strom, Kenneth; Browne, Alan L.; Johnson, Nancy

    2008-03-01

    Pedestrian protection has become an increasingly important aspect of automotive safety with new regulations taking effect around the world. Because it is increasingly difficult to meet these new regulations with traditional passive approaches, active lifts are being explored that increase the "crush zone" between the hood and rigid under-hood components as a means of mitigating the consequences of an impact with a non-occupant. Active lifts, however, are technically challenging because of the simultaneously high forces, stroke and quick timing resulting in most of the current devices being single use. This paper introduces the SMArt (Shape Memory Alloy ReseTable) Spring Lift, an automatically resetable and fully reusable device, which couples conventional standard compression springs to store the energy required for a hood lift, with Shape Memory Alloys actuators to achieve both an ultra high speed release of the spring and automatic reset of the system for multiple uses. Each of the four SMArt Device subsystems, lift, release, lower and reset/dissipate, are individually described. Two identical complete prototypes were fabricated and mounted at the rear corners of the hood, incorporated within a full-scale vehicle testbed at the SMARTT (Smart Material Advanced Research and Technology Transfer) lab at University of Michigan. Full operational cycle testing of a stationary vehicle in a laboratory setting confirms the ultrafast latch release, controlled lift profile, gravity lower to reposition the hood, and spring recompression via the ratchet engine successfully rearming the device for repeat cycles. While this is only a laboratory demonstration and extensive testing and development would be required for transition to a fielded product, this study does indicate that the SMArt Lift has promise as an alternative approach to pedestrian protection.

  9. 49 CFR 37.203 - Lift maintenance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Lift maintenance. 37.203 Section 37.203... DISABILITIES (ADA) Over-the-Road Buses (OTRBs) § 37.203 Lift maintenance. (a) The entity shall establish a system of regular and frequent maintenance checks of lifts sufficient to determine if they are...

  10. 30 CFR 57.16016 - Lift trucks.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Lift trucks. 57.16016 Section 57.16016 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... § 57.16016 Lift trucks. Fork and other similar types of lift trucks shall be operated with the:...

  11. 30 CFR 57.16016 - Lift trucks.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Lift trucks. 57.16016 Section 57.16016 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... § 57.16016 Lift trucks. Fork and other similar types of lift trucks shall be operated with the:...

  12. 30 CFR 56.16016 - Lift trucks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Lift trucks. 56.16016 Section 56.16016 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....16016 Lift trucks. Fork and other similar types of lift trucks shall be operated with the— (a)...

  13. 30 CFR 57.16016 - Lift trucks.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Lift trucks. 57.16016 Section 57.16016 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... § 57.16016 Lift trucks. Fork and other similar types of lift trucks shall be operated with the:...

  14. 30 CFR 56.16016 - Lift trucks.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Lift trucks. 56.16016 Section 56.16016 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....16016 Lift trucks. Fork and other similar types of lift trucks shall be operated with the— (a)...

  15. 30 CFR 57.16016 - Lift trucks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Lift trucks. 57.16016 Section 57.16016 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... § 57.16016 Lift trucks. Fork and other similar types of lift trucks shall be operated with the:...

  16. 30 CFR 57.16016 - Lift trucks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Lift trucks. 57.16016 Section 57.16016 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... § 57.16016 Lift trucks. Fork and other similar types of lift trucks shall be operated with the:...

  17. 49 CFR 37.203 - Lift maintenance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Lift maintenance. 37.203 Section 37.203... DISABILITIES (ADA) Over-the-Road Buses (OTRBs) § 37.203 Lift maintenance. (a) The entity shall establish a system of regular and frequent maintenance checks of lifts sufficient to determine if they are...

  18. 30 CFR 56.16016 - Lift trucks.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Lift trucks. 56.16016 Section 56.16016 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....16016 Lift trucks. Fork and other similar types of lift trucks shall be operated with the— (a)...

  19. 30 CFR 56.16016 - Lift trucks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Lift trucks. 56.16016 Section 56.16016 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....16016 Lift trucks. Fork and other similar types of lift trucks shall be operated with the— (a)...

  20. 30 CFR 56.16016 - Lift trucks.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Lift trucks. 56.16016 Section 56.16016 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....16016 Lift trucks. Fork and other similar types of lift trucks shall be operated with the— (a)...

  1. Vertical Lift - Not Just For Terrestrial Flight

    NASA Technical Reports Server (NTRS)

    Young, Larry A

    2000-01-01

    Autonomous vertical lift vehicles hold considerable potential for supporting planetary science and exploration missions. This paper discusses several technical aspects of vertical lift planetary aerial vehicles in general, and specifically addresses technical challenges and work to date examining notional vertical lift vehicles for Mars, Titan, and Venus exploration.

  2. 49 CFR 37.203 - Lift maintenance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... DISABILITIES (ADA) Over-the-Road Buses (OTRBs) § 37.203 Lift maintenance. (a) The entity shall establish a system of regular and frequent maintenance checks of lifts sufficient to determine if they are operative... 49 Transportation 1 2013-10-01 2013-10-01 false Lift maintenance. 37.203 Section...

  3. Bench-scale study of active mine water treatment using cement kiln dust (CKD) as a neutralization agent.

    PubMed

    Mackie, Allison L; Walsh, Margaret E

    2012-02-01

    The overall objective of this study was to investigate the potential impact on settled water quality of using cement kiln dust (CKD), a waste by-product, to replace quicklime in the active treatment of acidic mine water. Bench-scale experiments were conducted to evaluate the treatment performance of calcium hydroxide (Ca(OH)(2)) slurries generated using four different CKD samples compared to a control treatment with quicklime (CaO) in terms of reducing acidity and metals concentrations in acid mine drainage (AMD) samples taken from the effluent of a lead/zinc mine in Atlantic Canada. Results of the study showed that all of the CKD samples evaluated were capable of achieving greater than 97% removal of total zinc and iron. The amount of solid alkaline material required to achieve pH targets required for neutralization of the AMD was found to be higher for treatment with the CKD slurries compared to the quicklime slurry control experiments, and varied linearly with the free lime content of the CKD. The results of this study also showed that a potential benefit of treating mine water with CKD could be reduced settled sludge volumes generated in the active treatment process, and further research into the characteristics of the sludge generated from the use of CKD-generated calcium hydroxide slurries is recommended.

  4. Forensic Analysis of Lunar Dust and Spacesuit Mitigation

    NASA Astrophysics Data System (ADS)

    Anneliese Lawrence, J.; Lindsay, John; Noble, Sarah

    2008-03-01

    A study was performed by authors to analyze dust lifted from Jack Schmitt's EVA space suit from Apollo 17 for mineralogy and grain size distributions for the 1,200 sampled particles. The grains were viewed through an SEM, photographed and analyzed using EDS equipment and mathematical computations. This study yielded counterintuitive results to be discussed in this presentation. Also discussed are magnetic properties of lunar dust.

  5. The global transport of dust

    USGS Publications Warehouse

    Griffin, Dale W.; Kellogg, C.A.; Garrison, V.H.; Shinn, E.A.

    2002-01-01

    By some estimates as much as two billion metric tons of dust are lifted into the Earth's atmosphere every year. Most of this dust is stirred up by storms, the more dramatic of which are aptly named dust storms. But more than mere dirt is carried aloft. Drifting with the suspended dust particles are soil pollutants such as herbicides and pesticides and a significant number of microorganisms-bacteria, viruses and fungi. We can gain some appreciation of how much microbial life is actually floating in our atmosphere by performing a quick calculation. There are typically about one million bacteria per gram of soil, but let's be conservative and suppose there are only 10,000 bacteria per gram of airborne sediment. Assuming a modest one billion metric tons of sediment in the atmosphere, these numbers translate into a quintillion (1018) sediment-borne bacteria moving around the planet each year-enough to form a microbial bridge between Earth and Jupiter. Here we consider what we've learned about the airborne transport of sediment across the globe, and review some of the remarkable studies in this reemerging field that had it origins more than 100 years ago.

  6. Serrated trailing edges for improving lift and drag characteristics of lifting surfaces

    NASA Technical Reports Server (NTRS)

    Vijgen, Paul M. H. W. (Inventor); Howard, Floyd G. (Inventor); Bushnell, Dennis M. (Inventor); Holmes, Bruce J. (Inventor)

    1992-01-01

    An improvement in the lift and drag characteristics of a lifting surface is achieved by attaching a serrated panel to the trailing edge of the lifting surface. The serrations may have a saw-tooth configuration, with a 60 degree included angle between adjacent serrations. The serrations may vary in shape and size over the span-wise length of the lifting surface, and may be positioned at fixed or adjustable deflections relative to the chord of the lifting surface.

  7. Numerical simulation of lifting mechanism

    NASA Astrophysics Data System (ADS)

    Gebel, E. S.; Zhursenbaev, B. I.; Solomin, V. Yu.

    2012-11-01

    The article presents a method of kinematical synthesis of planar multilink linkage with adjustable closed loop, which is designed for a plane-parallel motion of the output lever and can be used as an actuator for lifting mechanism. Methods of kinematical synthesis and analysis are developed in this paper allow to design the scheme of mechanism that performs the given function of displacement of the output link, and to evaluate the kinematical characteristics of the designed layout.

  8. Quiet powered-lift propulsion

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Latest results of programs exploring new propulsion technology for powered-lift aircraft systems are presented. Topics discussed include results from the 'quiet clean short-haul experimental engine' program and progress reports on the 'quiet short-haul research aircraft' and 'tilt-rotor research aircraft' programs. In addition to these NASA programs, the Air Force AMST YC 14 and YC 15 programs were reviewed.

  9. THE AKARI 2.5-5.0 μm SPECTRAL ATLAS OF TYPE-1 ACTIVE GALACTIC NUCLEI: BLACK HOLE MASS ESTIMATOR, LINE RATIO, AND HOT DUST TEMPERATURE

    SciTech Connect

    Kim, Dohyeong; Im, Myungshin; Kim, Ji Hoon; Jun, Hyunsung David; Lee, Seong-Kook; Woo, Jong-Hak; Lee, Hyung Mok; Lee, Myung Gyoon; Nakagawa, Takao; Matsuhara, Hideo; Wada, Takehiko; Takagi, Toshinobu; Oyabu, Shinki; Ohyama, Youichi E-mail: mim@astro.snu.ac.kr

    2015-01-01

    We present 2.5-5.0 μm spectra of 83 nearby (0.002 < z < 0.48) and bright (K < 14 mag) type-1 active galactic nuclei (AGNs) taken with the Infrared Camera on board AKARI. The 2.5-5.0 μm spectral region contains emission lines such as Brβ (2.63 μm), Brα (4.05 μm), and polycyclic aromatic hydrocarbons (3.3 μm), which can be used for studying the black hole (BH) masses and star formation activity in the host galaxies of AGNs. The spectral region also suffers less dust extinction than in the ultra violet (UV) or optical wavelengths, which may provide an unobscured view of dusty AGNs. Our sample is selected from bright quasar surveys of Palomar-Green and SNUQSO, and AGNs with reverberation-mapped BH masses from Peterson et al. Using 11 AGNs with reliable detection of Brackett lines, we derive the Brackett-line-based BH mass estimators. We also find that the observed Brackett line ratios can be explained with the commonly adopted physical conditions of the broad line region. Moreover, we fit the hot and warm dust components of the dust torus by adding photometric data of SDSS, 2MASS, WISE, and ISO to the AKARI spectra, finding hot and warm dust temperatures of ∼1100 K and ∼220 K, respectively, rather than the commonly cited hot dust temperature of 1500 K.

  10. [Lifting procedures in cosmetic facial surgery].

    PubMed

    Jansma, J; Schepers, R H; Vissink, A

    2014-10-01

    A prominent characteristic of the aging face is the descent of skin and subcutaneous tissues. In order to reduce this and create a more youthful appearance, several lifting procedures can be employed. In the forehead and eyebrow region the transblepharoplastic brow lift, the direct brow lift, the temporal brow lift, the coronal brow lift and the endoscopic brow lift can be distinguished. For the mid-face, the facelift is known to be an effective treatment for aging characteristics. Classic facelifts can be divided into the one layer-, two layer- and the deep plane facelift. Nowadays the minimal access cranial suspension lift is popular. The lifting capacity of this lift may be less, but the risk of complications is lower and the result is often more natural. A neck lift improves the chin-neck angle and a submental liposuction/lipectomy can contribute to this. Complications in lifting procedures are rare. Hematoma is the most frequent complication. Skin necrosis of the wound edges and laceration of the end branches of the facial nerve can also occur. There is a tendency towards minimally invasive procedures with smaller risk of complications and shorter recovery periods.

  11. Allometry of hummingbird lifting performance

    PubMed Central

    Altshuler, D. L.; Dudley, R.; Heredia, S. M.; McGuire, J. A.

    2010-01-01

    Vertical lifting performance in 67 hummingbird species was studied across a 4000 m elevational gradient. We used the technique of asymptotic load-lifting to elicit maximum sustained muscle power output during loaded hovering flight. Our analysis incorporated direct measurements of maximum sustained load and simultaneous wingbeat kinematics, together with aerodynamic estimates of mass-specific mechanical power output, all within a robust phylogenetic framework for the Trochilidae. We evaluated key statistical factors relevant to estimating slopes for allometric relationships by performing analyses with and without phylogenetic information, and incorporating species-specific measurement error. We further examined allometric relationships at different elevations because this gradient represents a natural experiment for studying physical challenges to animal flight mechanics. Maximum lifting capacity (i.e. vertical force production) declined with elevation, but was either isometric or negatively allometric with respect to both body and muscle mass, depending on elevational occurrence of the corresponding taxa. Maximum relative muscle power output exhibited a negative allometry with respect to muscle mass, supporting theoretical predictions from muscle mechanics. PMID:20154187

  12. Lift enhancement by bats' dynamically changing wingspan.

    PubMed

    Wang, Shizhao; Zhang, Xing; He, Guowei; Liu, Tianshu

    2015-12-01

    This paper elucidates the aerodynamic role of the dynamically changing wingspan in bat flight. Based on direct numerical simulations of the flow over a slow-flying bat, it is found that the dynamically changing wingspan can significantly enhance the lift. Further, an analysis of flow structures and lift decomposition reveal that the elevated vortex lift associated with the leading-edge vortices intensified by the dynamically changing wingspan considerably contributed to enhancement of the time-averaged lift. The nonlinear interaction between the dynamically changing wing and the vortical structures plays an important role in the lift enhancement of a flying bat in addition to the geometrical effect of changing the lifting-surface area in a flapping cycle. In addition, the dynamically changing wingspan leads to the higher efficiency in terms of generating lift for a given amount of the mechanical energy consumed in flight. PMID:26701882

  13. Lift enhancement by bats' dynamically changing wingspan.

    PubMed

    Wang, Shizhao; Zhang, Xing; He, Guowei; Liu, Tianshu

    2015-12-01

    This paper elucidates the aerodynamic role of the dynamically changing wingspan in bat flight. Based on direct numerical simulations of the flow over a slow-flying bat, it is found that the dynamically changing wingspan can significantly enhance the lift. Further, an analysis of flow structures and lift decomposition reveal that the elevated vortex lift associated with the leading-edge vortices intensified by the dynamically changing wingspan considerably contributed to enhancement of the time-averaged lift. The nonlinear interaction between the dynamically changing wing and the vortical structures plays an important role in the lift enhancement of a flying bat in addition to the geometrical effect of changing the lifting-surface area in a flapping cycle. In addition, the dynamically changing wingspan leads to the higher efficiency in terms of generating lift for a given amount of the mechanical energy consumed in flight.

  14. Generalised Eisenhart lift of the Toda chain

    SciTech Connect

    Cariglia, Marco; Gibbons, Gary

    2014-02-15

    The Toda chain of nearest neighbour interacting particles on a line can be described both in terms of geodesic motion on a manifold with one extra dimension, the Eisenhart lift, or in terms of geodesic motion in a symmetric space with several extra dimensions. We examine the relationship between these two realisations and discover that the symmetric space is a generalised, multi-particle Eisenhart lift of the original problem that reduces to the standard Eisenhart lift. Such generalised Eisenhart lift acts as an inverse Kaluza-Klein reduction, promoting coupling constants to momenta in higher dimension. In particular, isometries of the generalised lift metric correspond to energy preserving transformations that mix coordinates and coupling constants. A by-product of the analysis is that the lift of the Toda Lax pair can be used to construct higher rank Killing tensors for both the standard and generalised lift metrics.

  15. Radioactively contaminated electric arc furnace dust as an addition to the immobilization mortar in low- and medium-activity repositories.

    PubMed

    Castellote, Marta; Menéndez, Esperanza; Andrade, Carmen; Zuloaga, Pablo; Navarro, Mariano; Ordóñez, Manuel

    2004-05-15

    Electric arc furnace dust (EAFD), generated by the steel-making industry, is in itself an intrinsic hazardous waste; however, the case may also be that scrap used in the process is accidentally contaminated by radioactive elements such as cesium. In this case the resulting EAFD is to be handled as radioactive waste, being duly confined in low- and medium-activity repositories (LMAR). What this paper studies is the reliability of using this radioactive EAFD as an addition in the immobilization mortar of the containers of the LMAR, that is, from the point of view of the durability. Different mixes of mortar containing different percentages of EAFD have been subjected to flexural and compressive strength, initial and final setting time, XRD study, total porosity and pore size distribution, determination of the chloride diffusion coefficient, dimensional stability tests, hydration heat, workability of the fresh mix, and leaching behavior. What is deduced from the results is that for the conditions used in this research, (cement + sand) can be replaced by EAFD upto a ratio [EAFD/(cement + EAFD)] of 46% in the immobilization mortar of LMAR, apparently without any loss in the long-term durability properties of the mortar.

  16. PARP is activated in human asthma and its inhibition by olaparib blocks house dust mite-induced disease in mice

    PubMed Central

    Ghonim, Mohamed A.; Pyakurel, Kusma; Ibba, Salome V.; Wang, Jeffrey; Rodriguez, Paulo; Al-Khami, Amir A.; Lammi, Matthew R.; Kim, Hogyoung; Zea, Arnold H.; Davis, Christian; Okpechi, Samuel; Wyczechowska, Dorota; Al-Ghareeb, Kamel; Mansy, Moselhy S.; Ochoa, Augusto; Naura, Amarjit S.

    2015-01-01

    Our laboratory established a role for poly(ADP-ribose)polymerase (PARP) in asthma. To increase the clinical significance of our studies, it is imperative to demonstrate that PARP is actually activated in human asthma, to examine whether a PARP inhibitor approved for human testing such as olaparib blocks already-established chronic asthma traits in response to house dust mite (HDM), a true human allergen, in mice and to examine whether the drug modulates human cluster of differentiation type 4 (CD4+) T-cell function. To conduct the study, human lung specimens and peripheral blood mononuclear cells (PBMCs) and a HDM-based mouse asthma model were used. Our results show that PARP is activated in PBMCs and lung tissues of asthmatics. PARP inhibition by olaparib or gene knockout blocked established asthma-like traits in mice chronically exposed to HDM including airway eosinophilia and hyper-responsiveness. These effects were linked to a marked reduction in T helper 2 (Th2) cytokine production without a prominent effect on interferon (IFN)-γ or interleukin (IL)-10. PARP inhibition prevented HDM-induced increase in overall cellularity, weight and CD4+ T-cell population in spleens of treated mice whereas it increased the T-regulatory cell population. In CD3/CD28-stimulated human CD4 +T-cells, olaparib treatment reduced Th2 cytokine production potentially by modulating GATA binding protein-3 (gata-3)/IL-4 expression while moderately affecting T-cell proliferation. PARP inhibition inconsistently increased IL-17 in HDM-exposed mice and CD3/CD28-stimulated CD4+ T cells without a concomitant increase in factors that can be influenced by IL-17. In the present study, we provide evidence for the first time that PARP-1 is activated in human asthma and that its inhibition is effective in blocking established asthma in mice. PMID:26205779

  17. The relationship between maximal lifting capacity and maximum acceptable lift in strength-based soldiering tasks.

    PubMed

    Savage, Robert J; Best, Stuart A; Carstairs, Greg L; Ham, Daniel J

    2012-07-01

    Psychophysical assessments, such as the maximum acceptable lift, have been used to establish worker capability and set safe load limits for manual handling tasks in occupational settings. However, in military settings, in which task demand is set and capable workers must be selected, subjective measurements are inadequate, and maximal capacity testing must be used to assess lifting capability. The aim of this study was to establish and compare the relationship between maximal lifting capacity and a self-determined tolerable lifting limit, maximum acceptable lift, across a range of military-relevant lifting tasks. Seventy male soldiers (age 23.7 ± 6.1 years) from the Australian Army performed 7 strength-based lifting tasks to determine their maximum lifting capacity and maximum acceptable lift. Comparisons were performed to identify maximum acceptable lift relative to maximum lifting capacity for each individual task. Linear regression was used to identify the relationship across all tasks when the data were pooled. Strong correlations existed between all 7 lifting tasks (rrange = 0.87-0.96, p < 0.05). No differences were found in maximum acceptable lift relative to maximum lifting capacity across all tasks (p = 0.46). When data were pooled, maximum acceptable lift was equal to 84 ± 8% of the maximum lifting capacity. This study is the first to illustrate the strong and consistent relationship between maximum lifting capacity and maximum acceptable lift for multiple single lifting tasks. The relationship developed between these indices may be used to help assess self-selected manual handling capability through occupationally relevant maximal performance tests.

  18. Validation of the plate-out model in the RADAX code used for plate-out and dust activity calculations at PBMR

    SciTech Connect

    Stassen, L.

    2006-07-01

    The two main sources of deposited activities in the Pebble Bed Modular Reactor's (PBMR) Main Power System (MPS), are plate-out of the small fraction of fission product activities released from the PBMR core, and deposition of these activities adsorbed on graphite dust generated during abrasion of the fuel spheres. PBMR uses the German code RADAX for the calculation of fission product transport, plate-out and dust deposition. In this paper a brief overview is given of the plate-out and dust deposition models implemented in the RADAX code. The results of testing activities that were performed for validation of the plate-out model in the RADAX code are also described. These tests form only part of the overall effort to fully verify and validate RADAX. For validation of the plate-out model, results from past experiments in the out-of-pile loop experiment LAMINAR, as well as the two reactor bypass loop experiments VAMPYR-II of the AVR and the DRAGON Hot Gas Duct, were used as test cases. In this paper, the approach used to set up and execute the test cases is briefly described, examples of the test results are given and discussed, and an evaluation of the ability of the results to validate the RADAX code is provided. (authors)

  19. Exploring the effects of seated whole body vibration exposure on repetitive asymmetric lifting tasks.

    PubMed

    Mehta, Jay P; Lavender, Steven A; Jagacinski, Richard J; Sommerich, Carolyn M

    2015-01-01

    This study investigated changes in the physiological and behavioral responses to repetitive asymmetric lifting activity after exposure to whole body vibrations. Seventeen healthy volunteers repeatedly lifted a box (15% of lifter's capacity) positioned in front of them at ankle level to a location on their left side at waist level at the rate of 10 lifts/min for a period of 60 minutes. Prior to lifting, participants were seated on a vibrating platform for 60 minutes; in one of the two sessions the platform did not vibrate. Overall, the physiological responses assessed using near-infrared spectroscopy signals for the erector spinae muscles decreased significantly over time during the seating and the lifting tasks (p < 0.001). During repetitive asymmetric lifting, behavioral changes included increases in peak forward bending motion, twisting movement, and three-dimensional movement velocities of the spine. The lateral bending movement of the spine and the duration of each lift decreased significantly over the 60 minutes of repetitive lifting. With exposure to whole body vibration, participants twisted farther (p = 0.046) and twisted faster (p = 0.025). These behavioral changes would suggest an increase in back injury risk when repetitive lifting tasks are preceded by whole body vibration exposure.

  20. Exploring the effects of seated whole body vibration exposure on repetitive asymmetric lifting tasks.

    PubMed

    Mehta, Jay P; Lavender, Steven A; Jagacinski, Richard J; Sommerich, Carolyn M

    2015-01-01

    This study investigated changes in the physiological and behavioral responses to repetitive asymmetric lifting activity after exposure to whole body vibrations. Seventeen healthy volunteers repeatedly lifted a box (15% of lifter's capacity) positioned in front of them at ankle level to a location on their left side at waist level at the rate of 10 lifts/min for a period of 60 minutes. Prior to lifting, participants were seated on a vibrating platform for 60 minutes; in one of the two sessions the platform did not vibrate. Overall, the physiological responses assessed using near-infrared spectroscopy signals for the erector spinae muscles decreased significantly over time during the seating and the lifting tasks (p < 0.001). During repetitive asymmetric lifting, behavioral changes included increases in peak forward bending motion, twisting movement, and three-dimensional movement velocities of the spine. The lateral bending movement of the spine and the duration of each lift decreased significantly over the 60 minutes of repetitive lifting. With exposure to whole body vibration, participants twisted farther (p = 0.046) and twisted faster (p = 0.025). These behavioral changes would suggest an increase in back injury risk when repetitive lifting tasks are preceded by whole body vibration exposure. PMID:25264920

  1. Amplification of dust loading in Martian dust devils by self-shadowing

    NASA Astrophysics Data System (ADS)

    Kuepper, M.; Wurm, G.

    2016-08-01

    Insolation of the Martian soil leads to a sub-surface overpressure due to thermal creep gas flow. This could support particle entrainment into the atmosphere. Short time shadowing e.g. by the traverse of a larger dust devil would enhance this effect. We find in microgravity experiments that mass ejection rates are increased by a factor of 10 for several seconds if a light source of 12.6 kW/m2 is turned off. Scaled to Mars this implies that self-shadowing of a partially opaque dust devil might lead to a strongly amplified flux of lifted material. We therefore suggest that self-shadowing might be a mechanism on Mars to increase the total dust loading of a dust devil and keep it self-sustained.

  2. Electrodynamic Dust Shield Demonstrator

    NASA Technical Reports Server (NTRS)

    Stankie, Charles G.

    2013-01-01

    The objective of the project was to design and manufacture a device to demonstrate a new technology developed by NASA's Electrostatics and Surface Physics Laboratory. The technology itself is a system which uses magnetic principles to remove regolith dust from its surface. This project was to create an enclosure that will be used to demonstrate the effectiveness of the invention to The Office of the Chief Technologist. ONE of the most important challenges of space exploration is actually caused by something very small and seemingly insignificant. Dust in space, most notably on the moon and Mars, has caused many unforeseen issues. Dirt and dust on Earth, while a nuisance, can be easily cleaned and kept at bay. However, there is considerably less weathering and erosion in space. As a result, the microscopic particles are extremely rough and abrasive. They are also electrostatically charged, so they cling to everything they make contact with. This was first noted to be a major problem during the Apollo missions. Dust would stick to the spacesuits, and could not be wiped off as predicted. Dust was brought back into the spacecraft, and was even inhaled by astronauts. This is a major health hazard. Atmospheric storms and other events can also cause dust to coat surfaces of spacecraft. This can cause abrasive damage to the craft. The coating can also reduce the effectiveness of thermal insulation and solar panels.' A group of engineers at Kennedy Space Center's Electrostatics and Surface Physics Laboratory have developed a new technology, called the Electrodynamic Dust Shield, to help alleviate these problems. It is based off of the electric curtain concept developed at NASA in 1967. "The EDS is an active dust mitigation technology that uses traveling electric fields to transport electrostatically charged dust particles along surfaces. To generate the traveling electric fields, the EDS consists of a multilayer dielectric coating with an embedded thin electrode grid

  3. Dust in the western U.S.: how biological, physical and human activities at the local scale interact to affect hydrologic function at the landscape scale (Invited)

    NASA Astrophysics Data System (ADS)

    Belnap, J.; Reheis, M. C.; Munson, S. M.

    2009-12-01

    Dryland regions constitute over 35% of terrestrial lands around the globe. Limited rainfall in these regions restricts plant growth and the spaces between vascular plants are often large. Most interspace soils are protected from wind erosion by the cover of rocks, physical crusts, and biological crusts (cyanobacteria, lichens, and mosses). However, disturbance of the soil surface in dryland regions (e.g., recreation, livestock, mining and energy exploration, military exercises, fire) reduces or eliminates the protective cover of the soils. Rising temperatures will reduce soil moisture and thus plant cover. Wind tunnel data show that most desert surfaces produce little sediment under typical wind speeds. However, disturbing the soil surface with vehicles, humans, or animals resulted in much higher sediment production from all surfaces tested, regardless of parent material, texture, or age of the soil surface. Synergist effects, such as surface disturbance occurring during drought periods in annualized plant communities, can create very large dust events. As surface disturbance, invasion, and drought are expected to increase in the future, an increase in dust production can be expected as well. Increased particulates in the air threaten human well-being through disease, highway accidents, and economic losses. Where dust losses are greater than the inputs, the source areas lose carbon and nutrients. These compounds are transferred to high elevation regions, where such fertilization likely impacts ecosystem function. Deposition of dust on the snowpack darkens the surface, increasing snowmelt by 30 days or more and exposing soils to evaporation, all of which decrease the quantity and quality of water in major streams and rivers. As increases occur in temperature, pumping of shallow aquifers, human activities, and invasion of exotic annual plants in dryland regions, the frequency, severity, and negative impact of dust storms is expected to increase as well. The

  4. Study of the Microphysical and Optical Properties of Ice Clouds and Dust Aerosols using observations made by active and passive satellite sensors in conjunction with modeling capabilities

    NASA Astrophysics Data System (ADS)

    Yang, P.; Dessler, A. E.

    2011-12-01

    Ice clouds and airborne dust aerosols are two unique and important components of atmospheric constituents. The passive sensors (e.g., MODIS, POLDER, and MISR) and active senor (CALIPSO-CALIOP) from the A-train constellation provide an unprecedented opportunity to investigate the microphysical and optical properties of ice clouds and dust aerosols. In this talk, we will demonstrate how to use the CALIPSO-CALIOP observations in conjunction with modeling capabilities to quantify the percentage of horizontally oriented ice crystals in ice clouds. At present, in remote sensing applications and radiative parameterizations involving ice clouds, ice crystals are assumed to be randomly oriented. Because the optical properties of horizontally and randomly oriented ice crystals are quite different, it is necessary to estimate the percentage of horizontally oriented ice crystals for a better understanding of the radiative properties of ice clouds. To infer the percentage of horizontally oriented particles, we have developed new modeling capabilities to simulate the single-scattering and multiple scattering (i.e., radiative transfer) processes involving these particles. Furthermore, we will demonstrate how to use the polarization measurements by CALIOP and POLDER to infer the morphologies of ice crystals and dust aerosols. Specifically, by minimizing the differences between radiative transfer simulations and observations, an optimal mixture of various ice crystal habits and the mean aspect ratio of dust aerosols are inferred. The outcomes of this effort may be potentially useful for more accurate parameterizations of the bulk radiative properties of ice clouds and dust aerosols for applications to radiative transfer simulations involved in climate models.

  5. Dust grains in the coma of 67P/Churyumov-Gerasimenko – link with surface properties and cometary activity

    NASA Astrophysics Data System (ADS)

    Capria, Maria Teresa; Ivanovski, Stavro; Zakharov, Vladimir; Capaccioni, Fabrizio; Filacchione, Gianrico; De Sanctis, Maria Cristina; rotundi, alessandra; della corte, vincenzo; Longobardo, Andrea; Palomba, Ernesto; colangeli, luigi; Bockelee-Morvan, Dominique; Érard, Stéphane; Leyrat, Cedric; VIRTIS, GIADA

    2016-10-01

    The imaging spectrometer VIRTIS and the dust analyzer GIADA, onboard Rosetta, made an extensive observation of the dust particles in the coma of the comet 67P/Churyumov-Gerasimenko. From the analysis of GIADA data, two different kind of particles have been revealed, compact and fluffy with different compositions and dynamical properties. Compact particles are characterized by densities of about 103 kg/m3, while fluffy particles have an almost fractal nature, with densities less than 1 kg/m3.In this work we present the initial results of a model linking the dust flux distribution, as obtained from a theoretical thermal nucleus model, with a model describing the dynamics of aspherical grains in the coma. The results are discussed in the context of the latest observations from VIRTIS and GIADA instruments.The 2D nucleus thermal model, when applied to the real shape of the comet, provides the size distribution and physical properties of the emitted grains at different times and location on the surface. The thermal model can simulate grains of various size distribution, composition and physical properties. This information is used as an input for the dust dynamical model that follows the emitted particles in the coma. The main source of heating is the solar illumination. In the dust dynamical model, the grain trajectory of emitted particles remains in a plane perpendicular to the rotational axis and the direction of illumination is taken to be in the same plane (i.e. does not cause transversal forces). The dust particles are assumed to be isothermal convex bodies and temperature changes only induce modest changes in the aerodynamic force (twice higher temperature changes aerodynamic force less than ~30%). This study reviews the theoretical values at which temperature difference starts to play a role on the dynamics. We discuss to what extent the particle's temperature affects the terminal velocities of the dust grains in the 67P coma in dependence on their mass and

  6. Dust Devils on Mars: Effects of Surface Roughness on Particle Threshold

    NASA Technical Reports Server (NTRS)

    Neakrase, Lynn D.; Greeley, Ronald; Iversen, James D.; Balme, Matthew L.; Foley, Daniel J.; Eddlemon, Eric E.

    2005-01-01

    Dust devils have been proposed as effective mechanisms for lofting large quantities of dust into the martian atmosphere. Previous work showed that vortices lift dust more easily than simple boundary layer winds. The aim of this study is to determine experimentally the effects of non-erodable roughness elements on vortex particle threshold through laboratory simulations of natural surfaces. Additional information is included in the original extended abstract.

  7. New and expected developments in artificial lift

    SciTech Connect

    Lea, J.F.; Winkler, H.W.

    1994-12-31

    Artificial lift is a broad subject. This paper discusses some of the new developments in the major areas of artificial lift. These are (1) beam lift, (2) electrical submersible pumping, (3) gas lift, (4) hydraulic pumping and (5) miscellaneous topics. The beam lift discussion concerns a new rod material, downhole measurements for rod loading, unit design and some miscellaneous topics. The ESP (Electrical Submersible Pump) section includes a discussion on solids handling, downhole sensor technology, new motor temperature limitations, motor efficiency, and other topics. The gas lift discussion includes mention of coiled tubing with gas lift valves internal, a surface controlled gas lift valve concept, and gas lift valve testing and modeling. Hydraulic pumping is used in many locations with deep pay and fairly small production rates. New hydraulic developments include a wider availability of power fluid pumps other than positive displacement pumps, and small jet pumps specifically designed for de-watering gas wells. Some miscellaneous developments include an insertable PC (progressing cavity) pump and improved plunger lift algorithms and equipment.

  8. Dust devils as observed by Mars Pathfinder

    NASA Astrophysics Data System (ADS)

    Ferri, Francesca; Smith, Peter H.; Lemmon, Mark; Rennó, Nilton O.

    2003-12-01

    Dust devils are localized meteorological phenomena frequently observed in terrestrial dry lands and desert landscapes as well as on Mars. They are low-pressure, warm core vortices that form at the bottom of convective plumes and loft dust from the surface. They move with the speed of the ambient wind and are tilted by wind shears. The Mars Pathfinder detected dust devils as dust plumes in the Imager for Mars Pathfinder images and as low-pressure convective vortices in the meteorological Mars Pathfinder Atmospheric Structure Investigation/Meteorology (ASI/MET) experiment data. The Pathfinder data have been analyzed in terms of dust devil size, spatial distribution, and frequency of occurrence. The results show that the Pathfinder imaging and MET observations are consistent with each other and with the observations made by the Viking 1 Orbiter and Mars Global Surveyor. The dust devil's ability to loft dust into the atmosphere has been investigated and a thermodynamic theory for dust devils has been used to calculate their physical parameters relevant to dust transport. The dust devils observed in an active day provide a pumping rate larger than the dust-settling rate derived from the optical obscuration of the Pathfinder rover solar panels. Therefore dust devils are a major factor in transporting dust from the surface to the atmosphere at the Pathfinder site.

  9. The fertilizing effect of actively accumulating dust - fractionation and within-soil distribution of soil phosphorus matters in a super-humid, high leaching environment, West Coast, New Zealand

    NASA Astrophysics Data System (ADS)

    Eger, A.; Almond, P. C.; Condron, L.

    2012-12-01

    Pedogenesis in humid climates, as found in chronosequence studies, ultimately leads to nutrient depletion and enhanced formation of secondary, less plant-available forms of nutrients with progressing time. Deposition of mineral dust has been shown to be an important process to mitigate such depletion in soils and ecosystems (e.g. Hawaii, Amazon Basin). However, the magnitude of its effect has hardly been quantified and little is known about the accession pathways. This study exploits a unique geomorphic setting of a Holocene sequence of sand dune ridges. This sequence combines an active dust flux gradient along a 6500 y-old dune downwind of a braided riverbed and, distal from the dust source, a chronosequence across the dunes (170-6500 y B.P.). Across the chronosequence, pedogenesis is very rapid with Spodosols developing after 1000 y under a thick organic root mat. Total soil phosphorus (P) across the chronosequence declined by 75% within 6500 y due to strong leaching losses of apatite P (82% loss). This decline was mirrored by a similar rapid decrease of foliar P concentrations across the chronosequence. Along the dust gradient we investigated the potential mitigation of soil P loss through dust deposition. We quantified the dust flux (from soil silt content and dust traps), dust P content, soil P fractions (total P, organic P, apatite P, occluded P, non-occluded P), and foliar P concentrations. Dust deposition rates decreased following a negative logarithmic model (R2=0.90, P< 0.001) from 28.4 to 11.7 g m-2 y-1 within 600 m from the river bed, reaching detection limit beyond 900 m. Dust, approximated by sampling river silts, showed an average P concentration of 1114 mg kg-1 compared to the 410 mg kg-1 P of the unweathered dune sand. Despite supplying up to 205 g m-2 of P to parts of dune ridge over the last 6500 y, no predictable increase of soil total P or mineral P with increasing dust flux was observed for the upper 50 cm of the soils along the dust gradient

  10. El Niño-Southern Oscillation influence on the dust storm activity in Australia: Can the past provide a key to the future?

    NASA Astrophysics Data System (ADS)

    Pudmenzky, C.; Stone, R.; Allan, R.; Butler, H.

    2011-12-01

    Wind erosion is an internationally recognised land degradation problem and affects approximately 28% of the global land area. The Australian continent is the largest dust source in the Southern Hemisphere with an emission rate of around 100 Tg yr-1 or approximate 5% of the global total. The climate (especially eastern Australian climate) is greatly influenced by the El Niño-Southern Oscillation (ENSO) which is the strongest natural fluctuation of climate on interannual time-scales and also affects climate conditions globally. ENSO is the core driver of extreme weather events such as drought, flooding, bushfires, dust storms and tropical cyclones and up to 50% of annual rainfall variability in northern and eastern Australia is linked to ENSO. These drier conditions will reduce vegetation cover and result in an increased dust storm activity in the future in central eastern Australia during dry El Niño phases of the Southern Oscillation. The Lake Eyre Basin, Channel Country and the Mallee region are the main dust source areas and severe dust storms have the potential to transport millions of tonnes of fertile topsoil from inland Australia to places as far as New Zealand, New Caledonia and Antarctic. The research project will investigate the influence of the ENSO on dust storm activity in Australia. This will be achieved through major reanalysis of past climate conditions for the past 150 years or more using the global 'Atmospheric Circulation Reconstruction over the Earth' (ACRE) project outputs which will reconstruct both upper-air dynamics, surface conditions and then all major dust storm events of the past. Australia has one of the most variable rainfall climates in the world and observational and modelling results suggest that more frequent or stronger ENSO events are possible in the future. Drought in Australia is probably the most economically costly climate event and has environmental and social impacts by reducing agricultural output and having social

  11. Road dust contribution to PM levels - Evaluation of the effectiveness of street washing activities by means of Positive Matrix Factorization

    NASA Astrophysics Data System (ADS)

    Karanasiou, Angeliki; Moreno, Teresa; Amato, Fulvio; Lumbreras, Julio; Narros, Adolfo; Borge, Rafael; Tobías, Aurelio; Boldo, Elena; Linares, Cristina; Pey, Jorge; Reche, Cristina; Alastuey, Andrés; Querol, Xavier

    2011-04-01

    The primary aim of this study was to quantify the contribution of road dust to airborne particulate matter (PM 10) and evaluate the effects of street washing on the mitigation of resuspension. With this purpose an intensive campaign was carried out in a heavily trafficked central road of Madrid (Spain) including PM 10 sampling and chemical analysis. PM 10 daily levels during dry, unwashed conditions were 2-15% higher than those present during the day after nightly street washing. However, this reduction is lower than the standard deviation of the PM 10 measurements. The diurnal variation of PM 10 revealed that a reduction in PM 10 was noticeable only during the morning hours. The emission sources for the urban area of Madrid were resolved by means of a receptor model, Positive Matrix Factorization, PMF. The results showed that the main sources were vehicle emissions, road dust, secondary aerosol including sulphate and nitrate, and soil. Vehicle emissions and road dust were the major contributor to PM 10 particle mass with similar average contributions of 31% and 29% respectively. The effect of street washing was also evaluated by examining the daily variation of the road dust source contribution between days with and without street washing. The mass contribution from the road dust source was ˜2 μg m -3 lower during the days that street washing was implemented with this corresponding to a reduction of 15% of its mass contribution during the days that the road surface was left untreated.

  12. A sensitive fluorescent assay for measuring the cysteine protease activity of Der p 1, a major allergen from the dust mite Dermatophagoides pteronyssinus.

    PubMed Central

    Schulz, O; Sewell, H F; Shakib, F

    1998-01-01

    The potent allergenicity of Der p 1, a major allergen of the house dust mite Dermatophagoides pteronyssinus, is thought to be related to its cysteine protease activity. Therefore, there is considerable interest in developing a sensitive assay for measuring Der p 1 activity to screen for specific inhibitors. This study demonstrates for the first time that the activity of Der p 1 can be measured conveniently in a continuous rate assay with the fluorogenic substrate Boc-Gln-Ala-Arg-AMC (K(m) = 280 microM and kcat/K(m) = 4.6 x 10(3)/M/s). PMID:9893750

  13. Cracked lifting lug welds on ten-ton UF{sub 6} cylinders

    SciTech Connect

    Dorning, R.E.

    1991-12-31

    Ten-ton, Type 48X, UF{sub 6} cylinders are used at the Portsmouth Gaseous Diffusion Plant to withdraw enriched uranium hexafluoride from the cascade, transfer enriched uranium hexafluoride to customer cylinders, and feed enriched product to the cascade. To accomplish these activities, the cylinders are lifted by cranes and straddle carriers which engage the cylinder lifting lugs. In August of 1988, weld cracks on two lifting lugs were discovered during preparation to lift a cylinder. The cylinder was rejected and tagged out, and an investigating committee formed to determine the cause of cracking and recommend remedial actions. Further investigation revealed the problem may be general to this class of cylinder in this use cycle. This paper discusses the actions taken at the Portsmouth site to deal with the cracked lifting lug weld problem. The actions include inspection activities, interim corrective actions, metallurgical evaluation of cracked welds, weld repairs, and current monitoring/inspection program.

  14. Proteolytic Activity Present in House-Dust-Mite Extracts Degrades ENA-78/CXCL5 and Reduces Neutrophil Migration.

    PubMed

    Keglowich, Laura; Tamm, Michael; Zhong, Jun; Miglino, Nicola; Borger, Pieter

    2014-01-01

    Background. Bronchial smooth muscle cells (BSMC) are a major source of proinflammatory and proangiogenic cytokines and chemokines, including VEGF and CXC-chemokines. CXC-chemokines act primarily on neutrophils, mediating their recruitment to and activation at the site of inflammation. In humans, house-dust mite (HDM) allergens can cause asthmatic exacerbations and trigger an inflammatory response through protease-dependent mechanisms. Objective. We investigated the effect HDM extract on the release of pro-angiogenic and proinflammatory cytokines from BSMC. Methods. Human primary BSMC were stimulated with HDM extract in the absence or presence of fetal calf serum (FCS). Twenty angiogenic cytokines were detected by a specific antibody array and modified protein levels were confirmed by ELISA. Neutrophil migration was measured using a 96-well Boyden chamber. Results. ENA-78/CXCL5 protein levels in conditioned medium of BSMC stimulated with HDM extract were significantly reduced (n = 10, P < 0.05) but restored in the presence of 5% FCS. HDM extracts did not affect ENA-78/CXCL5 mRNA levels. Recombinant ENA-78/CXCL5 was degraded after incubation with HDM extracts (n = 7, P < 0.05) but restored after the addition of the serine protease AEBSF. Neutrophil migration towards recombinant ENA-78/CXCL5 was also reduced in the presence of HDM extract. Conclusion. HDM proteases degrade ENA-78/CXCL5. Thus exposure to HDM allergens may alter ENA-78/CXCL5 levels in the lungs and may affect angiogenesis and the inflammatory response in the airways of asthma patients.

  15. Immunomodulation of airway epithelium cell activation by mesenchymal stromal cells ameliorates house dust mite-induced airway inflammation in mice.

    PubMed

    Duong, Khang M; Arikkatt, Jaisy; Ullah, M Ashik; Lynch, Jason P; Zhang, Vivian; Atkinson, Kerry; Sly, Peter D; Phipps, Simon

    2015-11-01

    Allergic asthma is underpinned by T helper 2 (Th2) inflammation. Redundancy in Th2 cytokine function and production by innate and adaptive immune cells suggests that strategies aimed at immunomodulation may prove more beneficial. Hence, we sought to determine whether administration of mesenchymal stromal cells (MSCs) to house dust mite (HDM) (Dermatophagoides pteronyssinus)-sensitized mice would suppress the development of Th2 inflammation and airway hyperresponsiveness (AHR) after HDM challenge. We report that the intravenous administration of allogeneic donor MSCs 1 hour before allergen challenge significantly attenuated the features of allergic asthma, including tissue eosinophilia, Th2 cytokine (IL-5 and IL-13) levels in bronchoalveolar lavage fluid, and AHR. The number of infiltrating type 2 innate lymphoid cells was not affected by MSC transfer, suggesting that MSCs may modulate the adaptive arm of Th2 immunity. The effect of MSC administration was long lasting; all features of allergic airway disease were significantly suppressed in response to a second round of HDM challenge 4 weeks after MSC administration. Further, we observed that MSCs decreased the release of epithelial cell-derived alarmins IL-1α and high mobility group box-1 in an IL-1 receptor antagonist-dependent manner. This significantly decreased the expression of the pro-Th2 cytokine IL-25 and reduced the number of activated and antigen-acquiring CD11c(+)CD11b(+) dendritic cells in the lung and mediastinal lymph nodes. Our findings suggest that MSC administration can ameliorate allergic airway inflammation by blunting the amplification of epithelial-derived inflammatory cytokines induced by HDM exposure and may offer long-term protection against Th2-mediated allergic airway inflammation and AHR.

  16. Dust Impact Monitor (SESAME-DIM) measurements at comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Krüger, Harald; Seidensticker, Klaus J.; Fischer, Hans-Herbert; Albin, Thomas; Apathy, Istvan; Arnold, Walter; Flandes, Alberto; Hirn, Attila; Kobayashi, Masanori; Loose, Alexander; Péter, Attila; Podolak, Morris

    2015-11-01

    Context. The Rosetta lander Philae successfully landed on the nucleus of comet 67P/Churyumov-Gerasimenko on 12 November 2014. Philae carries the Dust Impact Monitor (DIM) on board, which is part of the Surface Electric Sounding and Acoustic Monitoring Experiment (SESAME). DIM employs piezoelectric PZT sensors to detect impacts by submillimeter- and millimeter-sized ice and dust particles that are emitted from the nucleus and transported into the cometary coma. Aims: The DIM sensor measures dynamical data such as flux and the directionality of the impacting particles. Mass and speed of the particles can be constrained assuming density and elastic particle properties. Methods: DIM was operated during three mission phases of Philae at the comet: (1) before the separation of Philae from Rosetta at distances of about 9.6 km, 11.8 km, and 25.3 km from the nucleus barycenter. In this mission phase particles released from the nucleus on radial trajectories remained undetectable because of significant obscuration by the structures of Rosetta, and no dust particles were indeed detected; (2) during Philae's descent to its nominal landing site Agilkia, DIM detected one approximately millimeter-sized particle at a distance of 5.0 km from the nucleus' barycenter, corresponding to an altitude of 2.4 km from the surface. This is the closest ever dust detection at a cometary nucleus by a dedicated in situ dust detector; and (3) at Philae's final landing site, Abydos, DIM detected no dust impact which may be due to low cometary activity in the vicinity of Philae or due to shading by obstacles close to Philae, or both. Results: Laboratory calibration experiments showed that the material properties of the detected particle are compatible with a porous particle having a bulk density of approximately 250 kg m-3. The particle could have been lifted off the comet's surface by sublimating water ice.

  17. Influence of Lift Offset on Rotorcraft Performance

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2008-01-01

    The influence of lift offset on the performance of several rotorcraft configurations is explored. A lift-offset rotor, or advancing blade concept, is a hingeless rotor that can attain good efficiency at high speed, by operating with more lift on the advancing side than on the retreating side of the rotor disk. The calculated performance capability of modern-technology coaxial rotors utilizing a lift offset is examined, including rotor performance optimized for hover and high-speed cruise. The ideal induced power loss of coaxial rotors in hover and twin rotors in forward flight is presented. The aerodynamic modeling requirements for performance calculations are evaluated, including wake and drag models for the high speed flight condition. The influence of configuration on the performance of rotorcraft with lift-offset rotors is explored, considering tandem and side-by-side rotorcraft as well as wing-rotor lift share.

  18. Influence of Lift Offset on Rotorcraft Performance

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2009-01-01

    The influence of lift offset on the performance of several rotorcraft configurations is explored. A lift-offset rotor, or advancing blade concept, is a hingeless rotor that can attain good efficiency at high speed by operating with more lift on the advancing side than on the retreating side of the rotor disk. The calculated performance capability of modern-technology coaxial rotors utilizing a lift offset is examined, including rotor performance optimized for hover and high-speed cruise. The ideal induced power loss of coaxial rotors in hover and twin rotors in forward flight is presented. The aerodynamic modeling requirements for performance calculations are evaluated, including wake and drag models for the high-speed flight condition. The influence of configuration on the performance of rotorcraft with lift-offset rotors is explored, considering tandem and side-by-side rotorcraft as well as wing-rotor lift share.

  19. Dynamic analysis of plunger lift operations

    SciTech Connect

    Lea, J.F.

    1982-11-01

    Plunger lift is a method of artificial lift that uses a free piston traveling up and down inside the tubing in a cyclic manner. The piston serves to increase the efficiency of lifting liquids in gas/liquid production by reducing liquid fallback through the gas. Presented here is a description of a dynamic model of plunger lift operations that, as opposed to previous methods of analysis, includes calculation of the plunger velocity as the plunger and liquid slug travel up the tubing. Also, an analysis of plunger cycles in a high gas/liquid ratio (GLR) well is presented to indicate the maximum rate of slug buildup and the maximum casing pressure necessary to lift the plunger and accumulated liquids. The information presented allows a more detailed engineering approach to analyzing the performance of a plunger-lifted well.

  20. Lift-off of large-scale ultrathin nanomembranes

    NASA Astrophysics Data System (ADS)

    Miller, Joshua J.; Carter, Robert N.; McNabb, Kelly B.; DesOrmeaux, Jon-Paul S.; Striemer, Christopher C.; Winans, Joshua D.; Gaborski, Thomas R.

    2015-01-01

    Ultrathin silicon-based nanomembranes hold significant promise for advancements in applications ranging from separations to tissue engineering. Widespread application of these membranes has been hindered by their small active area, which typically ranges from square micrometers to square millimeters. These membranes are typically supported on silicon chips as small windows as a result of a time-consuming through-wafer etch process. This approach results in a relatively low active area and can be challenging to integrate into devices because of the rigid silicon support. In this paper, a lift-off approach is demonstrated wherein the membrane is supported by a polymeric scaffold and separated from the wafer to enable fabrication of membrane sheets (>75 cm2) with >80% active area. The wafer-scale lift-off process is demonstrated with 50 nm thick microporous and nanoporous silicon nitride (SiN) membranes. Release of large-scale SiN membranes is accomplished with both wet and dry lift-off techniques. The dry approach uses XeF2 gas to etch a sacrificial silicon film, while the wet etch uses buffered oxide etchant to remove a silicon dioxide sacrificial layer. Finally, it is demonstrated that lift-off membranes have excellent optical properties and can be used to support cell culture on a conventional scale.

  1. Dust storm simulation over Iran using HYSPLIT.

    PubMed

    Ashrafi, Khosro; Shafiepour-Motlagh, Majid; Aslemand, Alireza; Ghader, Sarmad

    2014-01-01

    Particulate matters have detrimental effects on human health, environment and economic. This pollutant may emit from anthropogenic or natural sources. On global scale, main proportion of natural particulate matter release to the atmosphere because of wind erosion from arid and semi-arid regions. Recently, the amount of dust coming from Arabian countries has dramatically increased, especially dust storms that are affecting western and even central parts of Iran. This phenomenon has caused a lot of environmental problems. Dust source identification and trajectory simulation using numerical techniques are the main aims of this study. HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model dust module and trajectory simulation are utilized in this research and two case studies are investigated (in May and June 2010). The base of the HYSPLIT dust module is the PM10 dust storm emission algorithm for desert land use. This methodology is applied to estimate hotspots and trajectories. Due to the results, dust storms started on May 17th and June 7th because of high wind shear (>8.5 m/s) from the western Syrian Desert. The source region limited to 32.50 °N to 33.80 °N and 38.00 °E to 38.80 °E coordinates. Dust plumes lifted and dispersed towards the east and southeast of the sources and reached Ahvaz on May 18th and June 8th. The average of PM10 concentration in these dates reached 625 and 494 μgm3 on Ahvaz monitoring stations, respectively. Moreover, the results gained from the model for dust motion simulation are similar to the MODIS satellite images. PMID:24397928

  2. Dust storm simulation over Iran using HYSPLIT

    PubMed Central

    2014-01-01

    Particulate matters have detrimental effects on human health, environment and economic. This pollutant may emit from anthropogenic or natural sources. On global scale, main proportion of natural particulate matter release to the atmosphere because of wind erosion from arid and semi-arid regions. Recently, the amount of dust coming from Arabian countries has dramatically increased, especially dust storms that are affecting western and even central parts of Iran. This phenomenon has caused a lot of environmental problems. Dust source identification and trajectory simulation using numerical techniques are the main aims of this study. HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model dust module and trajectory simulation are utilized in this research and two case studies are investigated (in May and June 2010). The base of the HYSPLIT dust module is the PM10 dust storm emission algorithm for desert land use. This methodology is applied to estimate hotspots and trajectories. Due to the results, dust storms started on May 17th and June 7th because of high wind shear (>8.5 m/s) from the western Syrian Desert. The source region limited to 32.50 °N to 33.80 °N and 38.00 °E to 38.80 °E coordinates. Dust plumes lifted and dispersed towards the east and southeast of the sources and reached Ahvaz on May 18th and June 8th. The average of PM10 concentration in these dates reached 625 and 494 μgm3 on Ahvaz monitoring stations, respectively. Moreover, the results gained from the model for dust motion simulation are similar to the MODIS satellite images. PMID:24397928

  3. Dust storm simulation over Iran using HYSPLIT.

    PubMed

    Ashrafi, Khosro; Shafiepour-Motlagh, Majid; Aslemand, Alireza; Ghader, Sarmad

    2014-01-07

    Particulate matters have detrimental effects on human health, environment and economic. This pollutant may emit from anthropogenic or natural sources. On global scale, main proportion of natural particulate matter release to the atmosphere because of wind erosion from arid and semi-arid regions. Recently, the amount of dust coming from Arabian countries has dramatically increased, especially dust storms that are affecting western and even central parts of Iran. This phenomenon has caused a lot of environmental problems. Dust source identification and trajectory simulation using numerical techniques are the main aims of this study. HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model dust module and trajectory simulation are utilized in this research and two case studies are investigated (in May and June 2010). The base of the HYSPLIT dust module is the PM10 dust storm emission algorithm for desert land use. This methodology is applied to estimate hotspots and trajectories. Due to the results, dust storms started on May 17th and June 7th because of high wind shear (>8.5 m/s) from the western Syrian Desert. The source region limited to 32.50 °N to 33.80 °N and 38.00 °E to 38.80 °E coordinates. Dust plumes lifted and dispersed towards the east and southeast of the sources and reached Ahvaz on May 18th and June 8th. The average of PM10 concentration in these dates reached 625 and 494 μgm3 on Ahvaz monitoring stations, respectively. Moreover, the results gained from the model for dust motion simulation are similar to the MODIS satellite images.

  4. Optimizing production with artificial lift systems

    SciTech Connect

    Patton, L.D. )

    1989-07-01

    There are four basic artificial lift systems in use today; gas-lift (GL), sucker rod pumping (SRP), electric subsurface centrifugal pumps (ESP), and subsurface hydraulic (SSHP). All of these systems are time proven and will satisfactorily perform the task for which they were designed. Once the factors that will influence the operation of a lift system have been defined, the design engineer must consider the advantages of the basic systems. The more common oil field problems which affect artificial lift are listed. The {ital relative} merits of each system with these problems are noted; however, the severity of any one of the adverse conditions may dictate the optimum system.

  5. The lift-fan aircraft: Lessons learned

    NASA Technical Reports Server (NTRS)

    Deckert, Wallace H.

    1995-01-01

    This report summarizes the highlights and results of a workshop held at NASA Ames Research Center in October 1992. The objective of the workshop was a thorough review of the lessons learned from past research on lift fans, and lift-fan aircraft, models, designs, and components. The scope included conceptual design studies, wind tunnel investigations, propulsion systems components, piloted simulation, flight of aircraft such as the SV-5A and SV-5B and a recent lift-fan aircraft development project. The report includes a brief summary of five technical presentations that addressed the subject The Lift-Fan Aircraft: Lessons Learned.

  6. Aerodynamic lift effect on satellite orbits

    NASA Technical Reports Server (NTRS)

    Karr, G. R.; Cleland, J. G.; Devries, L. L.

    1975-01-01

    Numerical quadrature is employed to obtain orbit perturbation results from the general perturbation equations. Both aerodynamic lift and drag forces are included in the analysis of the satellite orbit. An exponential atmosphere with and without atmospheric rotation is used. A comparison is made of the perturbations which are caused by atmospheric rotation with those caused by satellite aerodynamic effects. Results indicate that aerodynamic lift effects on the semi-major axis and orbit inclination can be of the same order as the effects of atmosphere rotation depending upon the orientation of the lift vector. The results reveal the importance of including aerodynamic lift effects in orbit perturbation analysis.

  7. Flow Control Research at NASA Langley in Support of High-Lift Augmentation

    NASA Technical Reports Server (NTRS)

    Sellers, William L., III; Jones, Gregory S.; Moore, Mark D.

    2002-01-01

    The paper describes the efforts at NASA Langley to apply active and passive flow control techniques for improved high-lift systems, and advanced vehicle concepts utilizing powered high-lift techniques. The development of simplified high-lift systems utilizing active flow control is shown to provide significant weight and drag reduction benefits based on system studies. Active flow control that focuses on separation, and the development of advanced circulation control wings (CCW) utilizing unsteady excitation techniques will be discussed. The advanced CCW airfoils can provide multifunctional controls throughout the flight envelope. Computational and experimental data are shown to illustrate the benefits and issues with implementation of the technology.

  8. Facial emphysema after sinus lift.

    PubMed

    Sakakibara, Akiko; Suzuki, Hiroaki; Yamashita, Atsuya; Hasegawa, Takumi; Minamikawa, Tsutomu; Furudoi, Shungo; Komori, Takahide

    2015-01-01

    An 80-year-old man with a history of en bloc resection of squamous cell carcinoma of the hard palate (T4aN0M0) was performed a lateral-window sinus lift of the edentulous area of the left maxillary molar region to facilitate future placement of dental implants.Two hours after the surgery, the patient complained of sudden malar swelling. Marked swelling was present from the left infraorbital region to the buccal region. The swelling was associated with air pockets at the alar base and in the angulus oculi medialis region and subcutaneous malar tissue. Emphysema appeared after the patient blew his nose. Therefore, the mucous membrane of the maxillary sinus might have had a small hole, and air might have entered the subcutaneous tissue via the bone window when the air pressure in the maxillary sinus increased with nose blowing. It is important to advise patients to avoid increasing the intraoral pressure after sinus-lift procedure. PMID:26088054

  9. Fuel Cell Powered Lift Truck

    SciTech Connect

    Moulden, Steve

    2015-08-20

    This project, entitled “Recovery Act: Fuel Cell-Powered Lift Truck Sysco (Houston) Fleet Deployment”, was in response to DOE funding opportunity announcement DE-PS36-08GO98009, Topic 7B, which promotes the deployment of fuel cell powered material handling equipment in large, multi-shift distribution centers. This project promoted large-volume commercialdeployments and helped to create a market pull for material handling equipment (MHE) powered fuel cell systems. Specific outcomes and benefits involved the proliferation of fuel cell systems in 5-to 20-kW lift trucks at a high-profile, real-world site that demonstrated the benefits of fuel cell technology and served as a focal point for other nascent customers. The project allowed for the creation of expertise in providing service and support for MHE fuel cell powered systems, growth of existing product manufacturing expertise, and promoted existing fuel cell system and component companies. The project also stimulated other MHE fleet conversions helping to speed the adoption of fuel cell systems and hydrogen fueling technology. This document also contains the lessons learned during the project in order to communicate the successes and difficulties experienced, which could potentially assist others planning similar projects.

  10. Dust formation in Milky Way-like galaxies

    NASA Astrophysics Data System (ADS)

    McKinnon, Ryan; Torrey, Paul; Vogelsberger, Mark

    2016-04-01

    We introduce a dust model for cosmological simulations implemented in the moving-mesh code AREPO and present a suite of cosmological hydrodynamical zoom-in simulations to study dust formation within galactic haloes. Our model accounts for the stellar production of dust, accretion of gas-phase metals on to existing grains, destruction of dust through local supernova activity, and dust driven by winds from star-forming regions. We find that accurate stellar and active galactic nuclei feedback is needed to reproduce the observed dust-metallicity relation and that dust growth largely dominates dust destruction. Our simulations predict a dust content of the interstellar medium which is consistent with observed scaling relations at z = 0, including scalings between dust-to-gas ratio and metallicity, dust mass and gas mass, dust-to-gas ratio and stellar mass, and dust-to-stellar mass ratio and gas fraction. We find that roughly two-thirds of dust at z = 0 originated from Type II supernovae, with the contribution from asymptotic giant branch stars below 20 per cent for z ≳ 5. While our suite of Milky Way-sized galaxies forms dust in good agreement with a number of key observables, it predicts a high dust-to-metal ratio in the circumgalactic medium, which motivates a more realistic treatment of thermal sputtering of grains and dust cooling channels.

  11. A note on the stochastic nature of particle cohesive force and implications to threshold friction velocity for aerodynamic dust entrainment

    NASA Astrophysics Data System (ADS)

    Shao, Yaping; Klose, Martina

    2016-09-01

    There is considerable interest to determine the threshold for aeolian dust emission on Earth and Mars. Existing schemes for threshold friction velocity are all deterministic in nature, but observations show that in the dust particle size range the threshold friction velocity scatters strongly due to stochastic inter-particle cohesion. In the real world, there always exists a certain amount of free dust which can be easily lifted from the surface by weak winds or even turbulence, as exemplified by dust devils. It has been proposed in the dust-devil research community, that the pressure drop at dust-devil center may be a major mechanism for dust-devil dust emission, known as the Δp effect. It is questioned here whether the Δp effect is substantial or whether the elevated dust concentration in dust devils is due to free dust emission. A simple analysis indicates that the Δp effect appears to be small and the dust in dust devils is probably due to free dust emission and dust convergence. To estimate free dust emission, it is useful to define a lower limit of dust-particle threshold friction velocity. A simple expression for this velocity is proposed by making assumptions to the median and variance of inter-particle cohesive force. The simple expression is fitted to the data of the Arizona State University Vortex Generator. While considerable uncertainty remains in the scheme, this note highlights the need for additional research on the stochastic nature of dust emission.

  12. Diagnostics for Dust Monitoring in Tokamak Environment

    SciTech Connect

    Rosanvallon, S.; Grisolia, C.; Hong, S. H.; Worms, J.

    2008-03-12

    During ITER lifetime, dusts and flakes will be produced due to the interaction of plasmas with the in-vessel materials or due to maintenance. They will be made of carbon, beryllium and tungsten and will be activated, tritiated and chemically reactive and toxic. Safety limits have been set in order to reduce dust hazards. Thus dust diagnostics and removal methods need to be developed for ITER within the constraints linked to magnetic field, radiation, vacuum and temperature. This paper reviews potential diagnostics to monitor the dust content using techniques already used for erosion or deposition monitoring or techniques specially developed for measuring dust in suspension.

  13. Computation of aerodynamic interference between lifting surfaces and lift- and cruise-fans

    NASA Technical Reports Server (NTRS)

    Dillenius, M. F. E.; Mendenhall, M. R.; Spangler, S. B.

    1974-01-01

    Sequence of three computer programs predicts aerodynamic interference on lifting surfaces of transport-type aircraft which are equipped with lift and cruise fans; for example, high-bypass-ratio engine and wing-pylon tail configuration or fuselage-mounted lift-fan and wing-tail configuration.

  14. Identifying errors in dust models from data assimilation

    NASA Astrophysics Data System (ADS)

    Pope, R. J.; Marsham, J. H.; Knippertz, P.; Brooks, M. E.; Roberts, A. J.

    2016-09-01

    Airborne mineral dust is an important component of the Earth system and is increasingly predicted prognostically in weather and climate models. The recent development of data assimilation for remotely sensed aerosol optical depths (AODs) into models offers a new opportunity to better understand the characteristics and sources of model error. Here we examine assimilation increments from Moderate Resolution Imaging Spectroradiometer AODs over northern Africa in the Met Office global forecast model. The model underpredicts (overpredicts) dust in light (strong) winds, consistent with (submesoscale) mesoscale processes lifting dust in reality but being missed by the model. Dust is overpredicted in the Sahara and underpredicted in the Sahel. Using observations of lighting and rain, we show that haboobs (cold pool outflows from moist convection) are an important dust source in reality but are badly handled by the model's convection scheme. The approach shows promise to serve as a useful framework for future model development.

  15. Dust eruptions by photophoresis and solid state greenhouse effects.

    PubMed

    Wurm, Gerhard; Krauss, Oliver

    2006-04-01

    We carried out experiments that show a gas pressure dependent ability of light to eject particles from a dust bed. Dust eruptions also occur upon removal of the light source. This can be attributed to a solid state greenhouse effect and photophoretic forces. This ejection mechanism works at light intensities larger than 6 kW/m2 but in extreme cases might work as low as 1 kW/m2. It can be applied to sunlit dust on Mars where it aids or triggers dust lift-off from the surface into the atmosphere. It is of importance for dusty bodies at the inner edge of protoplanetary disks where it leads to light induced erosion. The effect also offers a base for technical applications of dust removal in low pressure environments. PMID:16711990

  16. 33 CFR 118.85 - Lights on vertical lift bridges.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of...

  17. 33 CFR 118.85 - Lights on vertical lift bridges.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of...

  18. 33 CFR 118.85 - Lights on vertical lift bridges.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of...

  19. The Selection of a Van Lift or a Scooter.

    ERIC Educational Resources Information Center

    Stevens, John H.

    1990-01-01

    This newsletter issue describes 3-wheeled scooters and van lifts that can assist a person with a disability to drive independently or have access to transportation. The section on van lifts compares hydraulic lifts and electric lifts, lists manufacturers, and offers an "assessment quiz" outlining factors to consider in selecting a van lift. In the…

  20. A new method based on low background instrumental neutron activation analysis for major, trace and ultra-trace element determination in atmospheric mineral dust from polar ice cores.

    PubMed

    Baccolo, Giovanni; Clemenza, Massimiliano; Delmonte, Barbara; Maffezzoli, Niccolò; Nastasi, Massimiliano; Previtali, Ezio; Prata, Michele; Salvini, Andrea; Maggi, Valter

    2016-05-30

    Dust found in polar ice core samples present extremely low concentrations, in addition the availability of such samples is usually strictly limited. For these reasons the chemical and physical analysis of polar ice cores is an analytical challenge. In this work a new method based on low background instrumental neutron activation analysis (LB-INAA) for the multi-elemental characterization of the insoluble fraction of dust from polar ice cores is presented. Thanks to an accurate selection of the most proper materials and procedures it was possible to reach unprecedented analytical performances, suitable for ice core analyses. The method was applied to Antarctic ice core samples. Five samples of atmospheric dust (μg size) from ice sections of the Antarctic Talos Dome ice core were prepared and analyzed. A set of 37 elements was quantified, spanning from all the major elements (Na, Mg, Al, Si, K, Ca, Ti, Mn and Fe) to trace ones, including 10 (La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu) of the 14 natural occurring lanthanides. The detection limits are in the range of 10(-13)-10(-6) g, improving previous results of 1-3 orders of magnitude depending on the element; uncertainties lies between 4% and 60%.

  1. A new method based on low background instrumental neutron activation analysis for major, trace and ultra-trace element determination in atmospheric mineral dust from polar ice cores.

    PubMed

    Baccolo, Giovanni; Clemenza, Massimiliano; Delmonte, Barbara; Maffezzoli, Niccolò; Nastasi, Massimiliano; Previtali, Ezio; Prata, Michele; Salvini, Andrea; Maggi, Valter

    2016-05-30

    Dust found in polar ice core samples present extremely low concentrations, in addition the availability of such samples is usually strictly limited. For these reasons the chemical and physical analysis of polar ice cores is an analytical challenge. In this work a new method based on low background instrumental neutron activation analysis (LB-INAA) for the multi-elemental characterization of the insoluble fraction of dust from polar ice cores is presented. Thanks to an accurate selection of the most proper materials and procedures it was possible to reach unprecedented analytical performances, suitable for ice core analyses. The method was applied to Antarctic ice core samples. Five samples of atmospheric dust (μg size) from ice sections of the Antarctic Talos Dome ice core were prepared and analyzed. A set of 37 elements was quantified, spanning from all the major elements (Na, Mg, Al, Si, K, Ca, Ti, Mn and Fe) to trace ones, including 10 (La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu) of the 14 natural occurring lanthanides. The detection limits are in the range of 10(-13)-10(-6) g, improving previous results of 1-3 orders of magnitude depending on the element; uncertainties lies between 4% and 60%. PMID:27154827

  2. Spectral Energy Distributions of QSOs at z > 5: Common Active Galactic Nucleus-heated Dust and Occasionally Strong Star-formation

    NASA Astrophysics Data System (ADS)

    Leipski, C.; Meisenheimer, K.; Walter, F.; Klaas, U.; Dannerbauer, H.; De Rosa, G.; Fan, X.; Haas, M.; Krause, O.; Rix, H.-W.

    2014-04-01

    We present spectral energy distributions (SEDs) of 69 QSOs at z > 5, covering a rest frame wavelength range of 0.1 μm to ~80 μm, and centered on new Spitzer and Herschel observations. The detection rate of the QSOs with Spitzer is very high (97% at λrest <~ 4 μm), but drops toward the Herschel bands with 30% detected in PACS (rest frame mid-infrared) and 15% additionally in the SPIRE (rest frame far-infrared; FIR). We perform multi-component SED fits for Herschel-detected objects and confirm that to match the observed SEDs, a clumpy torus model needs to be complemented by a hot (~1300 K) component and, in cases with prominent FIR emission, also by a cold (~50 K) component. In the FIR-detected cases the luminosity of the cold component is of the order of 1013 L ⊙ which is likely heated by star formation. From the SED fits we also determine that the active galactic nucleus (AGN) dust-to-accretion disk luminosity ratio declines with UV/optical luminosity. Emission from hot (~1300 K) dust is common in our sample, showing that nuclear dust is ubiquitous in luminous QSOs out to redshift 6. However, about 15% of the objects appear under-luminous in the near infrared compared to their optical emission and seem to be deficient in (but not devoid of) hot dust. Within our full sample, the QSOs detected with Herschel are found at the high luminosity end in L UV/opt and L NIR and show low equivalent widths (EWs) in Hα and in Lyα. In the distribution of Hα EWs, as determined from the Spitzer photometry, the high-redshift QSOs show little difference to low-redshift AGN.

  3. The 60-μm extragalactic background radiation intensity, dust-enshrouded active galactic nuclei and the assembly of groups and clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Blain, A. W.; Phillips, T. G.

    2002-06-01

    Submillimetre- (submm-) wave observations have revealed a cosmologically significant population of high-redshift dust-enshrouded galaxies. The form of evolution inferred for this population can be reconciled easily with COBE FIRAS and DIRBE measurements of the cosmic background radiation (CBR) intensity at wavelengths longer than ~100μm. At shorter wavelengths, however, the 60-μm CBR intensity reported by Finkbeiner, Davis & Schlegel is less easily accounted for. Lagache et al. have proposed that this excess CBR emission is a warm Galactic component, and the detection of the highest-energy γ-rays from blazars limits the CBR intensity at these wavelengths, but here we investigate possible sources of this excess CBR emission, assuming that it has a genuine extragalactic origin. We propose and test three explanations, each involving additional populations of luminous, evolving galaxies not readily detected in existing submm-wave surveys. First, an additional population of dust-enshrouded galaxies with hot dust temperatures, perhaps dust-enshrouded, Compton-thick active galactic nuclei (AGN) as suggested by recent deep Chandra surveys. Secondly, a population of dusty galaxies with temperatures more typical of the existing submm-selected galaxies, but at relatively low redshifts. These could plausibly be associated with the assembly of groups and clusters of galaxies. Thirdly, a population of low-luminosity, cool, quiescent spiral galaxies. Hot AGN sources and the assembly of galaxy groups can account for the excess 60-μm background. There are significant problems with the cluster assembly scenario, in which too many bright 60-μm IRAS sources are predicted. Spiral galaxies have the wrong spectral energy distributions to account for the excess. Future wide-field far-infrared (IR) surveys at wavelengths of 70 and 250μm using the SIRTF and Herschel space missions will sample representative volumes of the distant Universe, allowing any hot population of dusty AGNs and

  4. Spectral energy distributions of QSOs at z > 5: Common active galactic nucleus-heated dust and occasionally strong star-formation

    SciTech Connect

    Leipski, C.; Meisenheimer, K.; Walter, F.; Klaas, U.; Krause, O.; Rix, H.-W.; Dannerbauer, H.; De Rosa, G.; Fan, X.; Haas, M.

    2014-04-20

    We present spectral energy distributions (SEDs) of 69 QSOs at z > 5, covering a rest frame wavelength range of 0.1 μm to ∼80 μm, and centered on new Spitzer and Herschel observations. The detection rate of the QSOs with Spitzer is very high (97% at λ{sub rest} ≲ 4 μm), but drops toward the Herschel bands with 30% detected in PACS (rest frame mid-infrared) and 15% additionally in the SPIRE (rest frame far-infrared; FIR). We perform multi-component SED fits for Herschel-detected objects and confirm that to match the observed SEDs, a clumpy torus model needs to be complemented by a hot (∼1300 K) component and, in cases with prominent FIR emission, also by a cold (∼50 K) component. In the FIR-detected cases the luminosity of the cold component is of the order of 10{sup 13} L {sub ☉} which is likely heated by star formation. From the SED fits we also determine that the active galactic nucleus (AGN) dust-to-accretion disk luminosity ratio declines with UV/optical luminosity. Emission from hot (∼1300 K) dust is common in our sample, showing that nuclear dust is ubiquitous in luminous QSOs out to redshift 6. However, about 15% of the objects appear under-luminous in the near infrared compared to their optical emission and seem to be deficient in (but not devoid of) hot dust. Within our full sample, the QSOs detected with Herschel are found at the high luminosity end in L {sub UV/opt} and L {sub NIR} and show low equivalent widths (EWs) in Hα and in Lyα. In the distribution of Hα EWs, as determined from the Spitzer photometry, the high-redshift QSOs show little difference to low-redshift AGN.

  5. Unraveling Local Dust Storm Structure on Mars: The Case of Northern Amazonis During Mars Year 24

    NASA Astrophysics Data System (ADS)

    Heavens, N. G.

    2015-12-01

    On an average Martian afternoon, two or three local dust storms are taking place somewhere on the planet. By definition, these storms range in area from a few square kilometers to hundreds of thousands, rarely surviving from sol to the next. After more than 40 years of observation, a great deal is known about where and when they occur, but very little is known about the structure and dynamics of individual storms. This contrast in our knowledge about local dust storms results from how they are observed. Daily global mapping of Mars in the visible has enabled an accurate census of storms as well as observation of their morphological diversity. However, even under ideal conditions, an individual storm is only observed by sounder-type instrumentation once or twice (if it is a large enough), providing an incomplete picture of structure of an individual storm. Early studies of cyclogenesis on Earth had a similar problem. Cyclones were many, but observations of individual cyclones, especially over the ocean, were sparse. The structure and dynamics of cyclones was unraveled by noting similarities in properties between certain classes of cyclones and using observational data to generate composite cyclones that could be analyzed and modeled. Variability within the composite also could be studied. Here I establish the existence of a well-defined class of Martian local dust storms defined by: (1) occurrence along the axis of the dark albedo feature in northern Amazonis Planitia (36 N, 155 W); (2) not being associated with lifting or cloudiness due to a baroclinic wave/frontal boundary at higher latitude; (3) being textured, that is, having dust clouds with sharp, well-defined features that are thought to indicate their clouds are supplied by the active lifting of dust; (4) having dust clouds organized in well-defined streets indicative of convective rolls. In Mars Year 24, such storms developed on thirteen occasions in northern fall and autumn. Using data from the Mars

  6. Interactive Soil Dust Aerosol Model in the GISS GCM. Part 1; Sensitivity of the Soil Dust Cycle to Radiative Properties of Soil Dust Aerosols

    NASA Technical Reports Server (NTRS)

    Perlwitz, Jan; Tegen, Ina; Miller, Ron L.

    2000-01-01

    The sensitivity of the soil dust aerosol cycle to the radiative forcing by soil dust aerosols is studied. Four experiments with the NASA/GISS atmospheric general circulation model, which includes a soil dust aerosol model, are compared, all using a prescribed climatological sea surface temperature as lower boundary condition. In one experiment, dust is included as dynamic tracer only (without interacting with radiation), whereas dust interacts with radiation in the other simulations. Although the single scattering albedo of dust particles is prescribed to be globally uniform in the experiments with radiatively active dust, a different single scattering albedo is used in those experiments to estimate whether regional variations in dust optical properties, corresponding to variations in mineralogical composition among different source regions, are important for the soil dust cycle and the climate state. On a global scale, the radiative forcing by dust generally causes a reduction in the atmospheric dust load corresponding to a decreased dust source flux. That is, there is a negative feedback in the climate system due to the radiative effect of dust. The dust source flux and its changes were analyzed in more detail for the main dust source regions. This analysis shows that the reduction varies both with the season and with the single scattering albedo of the dust particles. By examining the correlation with the surface wind, it was found that the dust emission from the Saharan/Sahelian source region and from the Arabian peninsula, along with the sensitivity of the emission to the single scattering albedo of dust particles, are related to large scale circulation patterns, in particular to the trade winds during Northern Hemisphere winter and to the Indian monsoon circulation during summer. In the other regions, such relations to the large scale circulation were not found. There, the dependence of dust deflation to radiative forcing by dust particles is probably

  7. Current Status of NASA's Heavy Lift Plans

    NASA Technical Reports Server (NTRS)

    Creech, Steve

    2010-01-01

    flighhe ability to assemble, prepare, launch, control and recover the Ares I configuration and compare performance to computer models. Component tests continue on the J-2X engine, which will put both the Ares I and Ares V upper stages into orbit. In addition, more than 100,000 parts have been manufactured or on the assembly line for the first J-2X powerpack and the first two development engines, with hot fire tests to begin in 2011. This paper will further detail the progress to date on the Ares V and planned activities for the remainder of 2010. In addition, the Ares V team has continued its outreach to potential user communities in science and national security. Through the Constellation Program, NASA has amassed an enormous knowledge base in the design, technologies, and operations of heavy lift launch vehicles that will be a national asset for any future launch vehicle decision. This early phase of the design presents the best opportunity to incorporate where possible the insights and needs of other users.

  8. Soccer Ball Lift Coefficients via Trajectory Analysis

    ERIC Educational Resources Information Center

    Goff, John Eric; Carre, Matt J.

    2010-01-01

    We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin…

  9. Improving Grading Consistency through Grade Lift Reporting

    ERIC Educational Resources Information Center

    Millet, Ido

    2010-01-01

    We define Grade Lift as the difference between average class grade and average cumulative class GPA. This metric provides an assessment of how lenient the grading was for a given course. In 2006, we started providing faculty members individualized Grade Lift reports reflecting their position relative to an anonymously plotted school-wide…

  10. 29 CFR 1926.453 - Aerial lifts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from the American National... 29 Labor 8 2011-07-01 2011-07-01 false Aerial lifts. 1926.453 Section 1926.453 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Scaffolds § 1926.453 Aerial lifts. (a)...

  11. 29 CFR 1926.453 - Aerial lifts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from the American National... 29 Labor 8 2014-07-01 2014-07-01 false Aerial lifts. 1926.453 Section 1926.453 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Scaffolds § 1926.453 Aerial lifts. (a)...

  12. 29 CFR 1926.453 - Aerial lifts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from the American National... 29 Labor 8 2010-07-01 2010-07-01 false Aerial lifts. 1926.453 Section 1926.453 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Scaffolds § 1926.453 Aerial lifts. (a)...

  13. Gas lift systems make ideal offshore workers

    SciTech Connect

    1999-05-01

    With a low initial installation cost and small footprint, gas lift systems are well suited for offshore installations where compressed gas is usually already available. These systems are used on multiple and slimhole completions and handle sandy conditions well. They are also used to kick off wells that will flow naturally once the heavier completion fluids leave the production string. Gas lift itself is a mature workaday technology. Measurement and control of gas flow is an area of intense development in gas lift technology. One new control method involves production of multiple completions through a single wellbore. Typically, gas lift valves are opened and closed through tubing pressure. But downhole measurement technology does not yet yield information good enough for stable gas lift control of multiple completions. Gas lift is proving to be a useful AL technique in conjunction with electric submersible pumps (ESP). Located above the ESP pump, the gas lift can reduce the head and allow greater flow. This is helpful when small casing restricts the size of the downhole ESP pump. Wells can usually be produced by the gas lift alone in case of ESP failure, or by replacing the ESP where schedules, high repair costs or low prices rule out repair.

  14. 49 CFR 37.203 - Lift maintenance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Lift maintenance. 37.203 Section 37.203 Transportation Office of the Secretary of Transportation TRANSPORTATION SERVICES FOR INDIVIDUALS WITH DISABILITIES (ADA) Over-the-Road Buses (OTRBs) § 37.203 Lift maintenance. (a) The entity shall establish...

  15. 49 CFR 37.203 - Lift maintenance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Lift maintenance. 37.203 Section 37.203 Transportation Office of the Secretary of Transportation TRANSPORTATION SERVICES FOR INDIVIDUALS WITH DISABILITIES (ADA) Over-the-Road Buses (OTRBs) § 37.203 Lift maintenance. (a) The entity shall establish...

  16. Training Guidelines: Fork Lift Truck Driving.

    ERIC Educational Resources Information Center

    Ceramics, Glass, and Mineral Products Industry Training Board, Harrow (England).

    This manual of operative training guidelines for fork lift truck driving has been developed by the Ceramics, Glass and Mineral Products Industry Training Board (Great Britain) in consultation with a number of firms which manufacture fork lift trucks or which already have training--programs for their use. The purpose of the guidelines is to assist…

  17. What's new in artificial lift

    SciTech Connect

    Lea, J.F.; Winker, H.W.

    1989-05-01

    New developments might be expected to decline as oil, and thus equipment and service, prices decrease. However, there is no indication that this is occurring. In fact, several new and innovative developments are covered in this article. Of the more unique are a new geometry pumping unit and a hydraulic powered sucker and rod system. Other items described in this article include: New pump-off controller; Automatic balancing for air balanced pumping units; New rod couplings; New pump plunger; Sucker rod pulsation dampener; Stripper type BOP; Rod coupling tool; ESP cable protectors; New ESP motor; VSD communications interface; ESP gas separator; Portable hydraulic production test unit; Casing gas lift plunger; Production shut-of valve; Ceramic material for pump parts; Pressure transmitter; and New versatile packer.

  18. High-lift aerodynamics: Prospects and plans

    NASA Technical Reports Server (NTRS)

    Olson, Lawrence E.

    1992-01-01

    The emergence of high-lift aerodynamics is reviewed as one of the key technologies to the development of future subsonic transport aircraft. Airport congestion, community noise, economic competitiveness, and safety - the drivers that make high-lift an important technology - are discussed. Attention is given to the potentially synergistic integration of high-lift aerodynamics with two other advanced technologies: ultra-high bypass ratio turbofan engines and hybrid laminar flow control. A brief review of the ongoing high-lift research program at Ames Research Center is presented. Suggestions for future research directions are made with particular emphasis on the development and validation of computational codes and design methods. It is concluded that the technology of high-lift aerodynamics analysis and design should move boldly into the realm of high Reynolds number, three-dimensional flows.

  19. E ring dust sources: Implications from Cassini's dust measurements

    NASA Astrophysics Data System (ADS)

    Spahn, Frank; Albers, Nicole; Hörning, Marcel; Kempf, Sascha; Krivov, Alexander V.; Makuch, Martin; Schmidt, Jürgen; Seiß, Martin; Miodrag Sremčević

    2006-08-01

    The Enceladus flybys of the Cassini spacecraft are changing our understanding of the origin and sustainment of Saturn's E ring. Surprisingly, beyond the widely accepted dust production caused by micrometeoroid impacts onto the atmosphereless satellites (the impactor-ejecta process), geophysical activities have been detected at the south pole of Enceladus, providing an additional, efficient dust source. The dust detector data obtained during the flyby E11 are used to identify the amount of dust produced in the impactor-ejecta process and to improve related modeling [Spahn, F., Schmidt, J., Albers, N., Hörning, M., Makuch, M., Seiß, M., Kempf, S., Srama, R., Dikarev, V.V., Helfert, S., Moragas-Klostermeyer, G., Krivov, A.V., Sremčević, M., Tuzzolino, A., Economou, T., Grün, E., 2006. Cassini dust measurements at Enceladus: implications for Saturn's E ring. Science, in press]. With this, we estimate the impact-generated dust contributions of the other E ring satellites and find significant differences in the dust ejection efficiency by two projectile families - the E ring particles (ERPs) and the interplanetary dust particles (IDPs). Together with the Enceladus south-pole source, the ERP impacts play a crucial role in the inner region, whereas the IDP impacts dominate the particle production in the outer E ring, possibly accounting for its large radial extent. Our results can be verified in future Cassini flybys of the E ring satellites. In this way poorly known parameters of the dust particle production in hypervelocity impacts can be constrained by comparison of the data and theory.

  20. Assessment of Iceland as a dust source

    NASA Astrophysics Data System (ADS)

    Arnalds, Ólafur; Ólafsson, Haraldur; Dagsson-Waldhauserova, Pavla

    2016-04-01

    Iceland has extremely active dust sources that result in large-scale emissions and deposition on land and at sea. The dust has a volcanogenic origin of basaltic composition with about 10% Fe content. We used two independent methods to quantify dust emission from Iceland and dust deposition at sea. Firstly, the aerial extent (map) of deposition on land was extended to ocean areas around Iceland. Secondly, surveys of the number of dust events over the past decades and calculations of emissions and sea deposition for the dust storms were made. The results show that total emissions range from 30.5 (dust-event-based calculation) to 40.1 million t yr

  1. Lunar Dust: Characterization and Mitigation

    NASA Technical Reports Server (NTRS)

    Hyatt. Mark J.; Feighery, John

    2007-01-01

    Lunar dust is a ubiquitous phenomenon which must be explicitly addressed during upcoming human lunar exploration missions. Near term plans to revisit the moon as a stepping stone for further exploration of Mars, and beyond, places a primary emphasis on characterization and mitigation of lunar dust. Comprised of regolith particles ranging in size from tens of nanometers to microns, lunar dust is a manifestation of the complex interaction of the lunar soil with multiple mechanical, electrical, and gravitational effects. The environmental and anthropogenic factors effecting the perturbation, transport, and deposition of lunar dust must be studied in order to mitigate it's potentially harmful effects on exploration systems. The same hold true for assessing the risk it may pose for toxicological health problems if inhaled. This paper presents the current perspective and implementation of dust knowledge management and integration, and mitigation technology development activities within NASA's Exploration Technology Development Program. This work is presented within the context of the Constellation Program's Integrated Lunar Dust Management Strategy. This work further outlines the scientific basis for lunar dust behavior, it's characteristics and potential effects, and surveys several potential strategies for its control and mitigation both for lunar surface operations and within the working volumes of a lunar outpost. The paper also presents a perspective on lessons learned from Apollo and forensics engineering studies of Apollo hardware.

  2. Respiratory Toxicity of Lunar Highland Dust

    NASA Technical Reports Server (NTRS)

    James, John T.; Lam, Chiu-wing; Wallace, William T.

    2009-01-01

    Lunar dust exposures occurred during the Apollo missions while the crew was on the lunar surface and especially when microgravity conditions were attained during rendezvous in lunar orbit. Crews reported that the dust was irritating to the eyes and in some cases respiratory symptoms were elicited. NASA s vision for lunar exploration includes stays of 6 months on the lunar surface hence the health effects of periodic exposure to lunar dust need to be assessed. NASA has performed this assessment with a series of in vitro and in vivo tests on authentic lunar dust. Our approach is to "calibrate" the intrinsic toxicity of lunar dust by comparison to a nontoxic dust (TiO2) and a highly toxic dust (quartz) using intratrachael instillation of the dusts in mice. A battery of indices of toxicity is assessed at various time points after the instillations. Cultures of selected cells are exposed to test dusts to assess the adverse effects on the cells. Finally, chemical systems are used to assess the nature of the reactivity of various dusts and to determine the persistence of reactivity under various environmental conditions that are relevant to a space habitat. Similar systems are used to assess the dissolution of the dust. From these studies we will be able to set a defensible inhalation exposure standard for aged dust and predict whether we need a separate standard for reactive dust. Presently-available data suggest that aged lunar highland dust is slightly toxic, that it can adversely affect cultured cells, and that the surface reactivity induced by grinding the dust persists for a few hours after activation.

  3. Method for calculating wing characteristics by lifting-line theory using nonlinear section lift data

    NASA Technical Reports Server (NTRS)

    Sivells, James C; Neely, Robert H

    1947-01-01

    A method is presented for calculating wing characteristics by lifting-line theory using nonlinear section lift data. Material from various sources is combined with some original work into the single complete method described. Multhopp's systems of multipliers are employed to obtain the induced angle of attack directly from the spanwise lift distribution. Equations are developed for obtaining these multipliers for any even number of spanwise stations, and values are tabulated for 10 stations along the semispan for asymmetrical, symmetrical, and antisymmetrical lift distributions. In order to minimize the computing time and to illustrate the procedures involved, simplified computing forms containing detailed examples are given for symmetrical lift distributions. Similar forms for asymmetrical and antisymmetrical lift distributions, although not shown, can be readily constructed in the same manner as those given. The adaptation of the method for use with linear section lift data is also illustrated. The adaptation has been found to require less computing time than most existing methods.

  4. Canyon Dust

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03682 Canyon Dust

    These dust slides are located on the wall of Thithonium Chasma.

    Image information: VIS instrument. Latitude -4.1N, Longitude 275.7E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  5. Dust Slides

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03677 Linear Clouds

    Dust slides are common in the dust covered region called Lycus Sulci. A large fracture is also visible in this image.

    Image information: VIS instrument. Latitude 28.1N, Longitude 226.3E. 18 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  6. Dust agglomeration

    NASA Technical Reports Server (NTRS)

    2000-01-01

    John Marshall, an investigator at Ames Research Center and a principal investigator in the microgravity fluid physics program, is studying the adhesion and cohesion of particles in order to shed light on how granular systems behave. These systems include everything from giant dust clouds that form planets to tiny compressed pellets, such as the ones you swallow as tablets. This knowledge should help us control the grains, dust, and powders that we encounter or use on a daily basis. Marshall investigated electrostatic charge in microgravity on the first and second U.S. Microgravity Laboratory shuttle missions to see how grains aggregate, or stick together. With gravity's effects eliminated on orbit, Marshall found that the grains of sand that behaved ever so freely on Earth now behaved like flour. They would just glom together in clumps and were quite difficult to disperse. That led to an understanding of the prevalence of the electrostatic forces. The granules wanted to aggregate as little chains, like little hairs, and stack end to end. Some of the chains had 20 or 30 grains. This phenomenon indicated that another force, what Marshall believes to be an electrostatic dipole, was at work.(The diagram on the right emphasizes the aggregating particles in the photo on the left, taken during the USML-2 mission in 1995.)

  7. View of West end of central lift span truss web ...

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

    View of West end of central lift span truss web of Tensaw River Bridge, showing web brace of lift girder superstructure, looking west - Tensaw River Lift Bridge, Spanning Tensaw River at U.S. Highway 90, Mobile, Mobile County, AL

  8. View north; detail of lifting points at south end of ...

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

    View north; detail of lifting points at south end of lift span. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Lift Bridge, Mouth of Reserve Basin, League Island, Philadelphia, Philadelphia County, PA

  9. 9. VIEW LOOKING SOUTHWEST SHOWING TOP OF LIFT SPAN AND ...

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

    9. VIEW LOOKING SOUTHWEST SHOWING TOP OF LIFT SPAN AND MACHINERY HOUSE; ADJACENT RAILROAD LIFT-BRIDGE TO THE RIGHT. - Carter Road Lift Bridge, Spanning Cuyahoga River at Carter Road, Cleveland, Cuyahoga County, OH

  10. CALIPSO observations of changes in dust properties during transatlantic transport

    NASA Astrophysics Data System (ADS)

    Marshak, A.; Yang, W.; Varnai, T.; Kostinski, A. B.

    2015-12-01

    The vertical distribution of dust shape and size is highly important for understanding and estimating dust radiative forcing. We used CALIPSO nighttime datasets to examine the vertical structure and evolution of Saharan dust during transatlantic transport. The results show that most Saharan dust is lifted to high altitude and descends after traveling thousands of km-s. Initially, the depolarization ratio and color ratio of Saharan dust are uniformly distributed along altitude, suggesting vertically constant particle size and shape distributions. During transport, the depolarization ratio of Saharan dust drops at lower altitudes, suggesting that particle shapes become less irregular; while at relatively high altitudes, the depolarization ratio of dust increases during transport. The changes observed during transport likely come from the effects of gravitational sorting caused by variations in particle shape and size. A simple model with only two shapes qualitatively captures these features and confirms that shape-induced differential settling contribute significantly to the observed vertical stratification of dust properties. In addition, the effect of clouds on dust properties will be also discussed.

  11. Interstellar Dust: Contributed Papers

    NASA Technical Reports Server (NTRS)

    Tielens, Alexander G. G. M. (Editor); Allamandola, Louis J. (Editor)

    1989-01-01

    A coherent picture of the dust composition and its physical characteristics in the various phases of the interstellar medium was the central theme. Topics addressed included: dust in diffuse interstellar medium; overidentified infrared emission features; dust in dense clouds; dust in galaxies; optical properties of dust grains; interstellar dust models; interstellar dust and the solar system; dust formation and destruction; UV, visible, and IR observations of interstellar extinction; and quantum-statistical calculations of IR emission from highly vibrationally excited polycyclic aromatic hydrocarbon (PAH) molecules.

  12. Roles of MAPK pathway activation during cytokine induction in BEAS-2B cells exposed to fine World Trade Center (WTC) dust.

    PubMed

    Wang, Shang; Prophete, Colette; Soukup, Joleen M; Chen, Lung-Chi; Costa, Max; Ghio, Andrew; Qu, Qingshan; Cohen, Mitchell D; Chen, Haobin

    2010-01-01

    The World Trade Center (WTC) collapse on September 11, 2001 released copious amounts of particulate matter (PM) into the atmosphere of New York City. Follow-up studies on persons exposed to the dusts have revealed a severely increased rate for asthma and other respiratory illnesses. There have only been a few studies that have sought to discern the possible mechanisms underlying these untoward pathologies. In one study, an increased cytokine release was detected in cells exposed to WTC fine dusts (PM₂.₅ fraction or WTC₂.₅). However, the mechanism(s) for these increases has yet to be fully defined. Because activation of the mitogen-activated protein kinase (MAPK) signaling pathways is known to cause cytokine induction, the current study was undertaken to analyze the possible involvement of these pathways in any increased cytokine formation by lung epithelial cells (as BEAS-2B cells) exposed to WTC₂.₅. Our results showed that exposure to WTC₂.₅ for 5 hr increased interleukin-6 (IL-6) mRNA expression in BEAS-2B cells, as well as its protein levels in the culture media, in a dose-dependent manner. Besides IL-6, cytokine multiplex analyses revealed that formation of IL-8 and -10 was also elevated by the exposure. Both extracellular signal-regulated kinase (ERK) and p38, but not c-Jun N-terminal protein kinase, signaling pathways were found to be activated in cells exposed to WTC₂.₅. Inactivation of ERK signaling pathways by PD98059 effectively blocked IL-6, -8, and -10 induction by WTC₂.₅; the p38 kinase inhibitor SB203580 significantly decreased induction of IL-8 and -10. Together, our data demonstrated activation of MAPK signaling pathway(s) likely played an important role in the WTC₂.₅-induced formation of several inflammatory (and, subsequently, anti-inflammatory) cytokines. The results are important in that they help to define one mechanism via which the WTC dusts may have acted to cause the documented increases in asthma and other

  13. News and Views: Betelgeuse bubbles up dust; Hydrothermal activity on early asteroids; Is this a record? Galaxy evolution in 3D; LOFAR looks farther; IOPD makes plans

    NASA Astrophysics Data System (ADS)

    2011-08-01

    Red supergiant star Betelgeuse is surrounded by a vast halo of silicate and aluminium dust, visible in false colour in this infrared image from the European Southern Observatory's Very Large Telescope. This material may eventually form planets around a new star. Biochemical analysis of the Tagish Lake meteorites, some of the most pristine samples of carbonaceous chondrites known, suggests that much of the variation in organic matter between different meteorite samples can be ascribed to hydrothermal activity on meteorite parent bodies. European Southern Observatory astronomers have discovered the most distant quasar yet - and reckon it is one of the brightest objects in the early universe.

  14. Status and Future of Dust Storm Forecasting

    NASA Astrophysics Data System (ADS)

    Westphal, D. L.

    2002-12-01

    In recent years, increased attention has been given to the large amounts of airborne dust derived from the deserts and desertified areas of the world and transported over scales ranging from local to global. This dust can have positive and negative impacts on human activities and the environment, including modifying cloud formation, fertilizing the ocean, degrading air quality, reducing visibility, transporting pathogens, and inducing respiratory problems. The atmospheric radiative forcing by the dust has implications for global climate change and presently is one of the largest unknowns in climate models. These uncertainties have lead to much of the funding for research into the sources, properties, and fate of atmospheric dust. As a result of advances in numerical weather prediction over the past decades and the recent climate research, we are now in a position to produce operational dust storm forecasts. International organizations and national agencies are developing programs for dust forecasting. The approaches and applications of dust detection and forecasting are as varied as the nations that are developing the models. The basic components of a dust forecasting system include atmospheric forcing, dust production, and dust microphysics. The forecasting applications include air and auto traffic safety, shipping, health, national security, climate and weather. This presentation will summarize the methods of dust storm forecasting and illustrate the various applications. The major remaining uncertainties (e.g. sources and initialization) will be discussed as well as approaches for solving those problems.

  15. Chemical constituents of fugitive dust.

    PubMed

    Van Pelt, R Scott; Zobeck, Ted M

    2007-07-01

    Wind erosion selectively winnows the fine, most chemically concentrated portions of surface soils and results in the inter-regional transport of fugitive dust containing plant nutrients, trace elements and other soil-borne contaminants. We sampled and analyzed surface soils, sediments in transport over eroding fields, and attic dust from a small area of the Southern High Plains of Texas to characterize the physical nature and chemical constituents of these materials and to investigate techniques that would allow relatively rapid, low cost techniques for estimating the chemical constituents of fugitive dust from an eroding field. From chemical analyses of actively eroding sediments, it would appear that Ca is the only chemical species that is enriched more than others during the process of fugitive dust production. We found surface soil sieved to produce a sub-sample with particle diameters in the range of 53-74 microm to be a reasonably good surrogate for fugitive dust very near the source field, that sieved sub-samples with particle diameters <10 microm have a crustal enrichment factor of approximately 6, and that this factor, multiplied by the chemical contents of source soils, may be a reasonable estimator of fugitive PM(10) chemistry from the soils of interest. We also found that dust from tractor air cleaners provided a good surrogate for dust entrained by tillage and harvesting operations if the chemical species resulting from engine wear and exhaust were removed from the data set or scaled back to the average of enrichment factors noted for chemical species with no known anthropogenic sources. Chemical analyses of dust samples collected from attics approximately 4 km from the nearest source fields indicated that anthropogenic sources of several environmentally important nutrient and trace element species are much larger contributors, by up to nearly two orders of magnitude, to atmospheric loading and subsequent deposition than fugitive dust from eroding

  16. Lunar Dust Mitigation Technology Development

    NASA Technical Reports Server (NTRS)

    Hyatt, Mark J.; Deluane, Paul B.

    2008-01-01

    NASA s plans for implementing the Vision for Space Exploration include returning to the moon as a stepping stone for further exploration of Mars, and beyond. Dust on the lunar surface has a ubiquitous presence which must be explicitly addressed during upcoming human lunar exploration missions. While the operational challenges attributable to dust during the Apollo missions did not prove critical, the comparatively long duration of impending missions presents a different challenge. Near term plans to revisit the moon places a primary emphasis on characterization and mitigation of lunar dust. Comprised of regolith particles ranging in size from tens of nanometers to microns, lunar dust is a manifestation of the complex interaction of the lunar soil with multiple mechanical, electrical, and gravitational effects. The environmental and anthropogenic factors effecting the perturbation, transport, and deposition of lunar dust must be studied in order to mitigate it s potentially harmful effects on exploration systems. This paper presents the current perspective and implementation of dust knowledge management and integration, and mitigation technology development activities within NASA s Exploration Technology Development Program. This work is presented within the context of the Constellation Program s Integrated Lunar Dust Management Strategy. The Lunar Dust Mitigation Technology Development project has been implemented within the ETDP. Project scope and plans will be presented, along with a a perspective on lessons learned from Apollo and forensics engineering studies of Apollo hardware. This paper further outlines the scientific basis for lunar dust behavior, it s characteristics and potential effects, and surveys several potential strategies for its control and mitigation both for lunar surface operations and within the working volumes of a lunar outpost.

  17. Rocket dust storms and detached dust layers in the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Spiga, Aymeric; Faure, Julien; Madeleine, Jean-Baptiste; Määttänen, Anni; Forget, François

    2013-04-01

    Airborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modeling that includes the transport of radiatively active dust to predict the evolution of a local dust storm monitored by OMEGA on board Mars Express. We show that the evolution of this dust storm is governed by deep convective motions. The supply of convective energy is provided by the absorption of incoming sunlight by dust particles, rather than by latent heating as in moist convection on Earth. We propose to use the terminology "rocket dust storm," or conio-cumulonimbus, to describe those storms in which rapid and efficient vertical transport takes place, injecting dust particles at high altitudes in the Martian troposphere (30-50 km). Combined to horizontal transport by large-scale winds, rocket dust storms produce detached layers of dust reminiscent of those observed with Mars Global Surveyor and Mars Reconnaissance Orbiter. Since nighttime sedimentation is less efficient than daytime convective transport, and the detached dust layers can convect during the daytime, these layers can be stable for several days. The peak activity of rocket dust storms is expected in low-latitude regions at clear seasons (late northern winter to late northern summer), which accounts for the high-altitude tropical dust maxima unveiled by Mars Climate Sounder. Dust-driven deep convection has strong implications for the Martian dust cycle, thermal structure, atmospheric dynamics, cloud microphysics, chemistry, and robotic and human exploration.

  18. Estimation of global anthropogenic dust aerosol using CALIOP satellite

    NASA Astrophysics Data System (ADS)

    Chen, B.; Huang, J.; Liu, J.

    2014-12-01

    Anthropogenic dust aerosols are those produced by human activity, which mainly come from cropland, pasture, and urban in this paper. Because understanding of the emissions of anthropogenic dust is still very limited, a new technique for separating anthropogenic dust from natural dustusing CALIPSO dust and planetary boundary layer height retrievalsalong with a land use dataset is introduced. Using this technique, the global distribution of dust is analyzed and the relative contribution of anthropogenic and natural dust sources to regional and global emissions are estimated. Local anthropogenic dust aerosol due to human activity, such as agriculture, industrial activity, transportation, and overgrazing, accounts for about 22.3% of the global continentaldust load. Of these anthropogenic dust aerosols, more than 52.5% come from semi-arid and semi-wet regions. On the whole, anthropogenic dust emissions from East China and India are higher than other regions.

  19. Influences of the position of the head on posture while lifting.

    PubMed

    Ishida, H; Watanabe, S; Eguchi, A; Kobara, K

    2008-01-01

    In clinical training of some lower back pain patients, teaching them to control their lumbar lordosis during lifting may be difficult. Therefore, another effective method for lifting technique is required. In standing, head cannot move without some compensating postural adjustment. The purpose of this study was to examine the influence of head position on lifting posture. Fourteen healthy male volunteers (22.6 +/- 4.4 years old) lifted a case while maintaining two different head positions; a downward position and an upright position. In the upright position, activities of the latissimus dorsi and vastus lateralis significantly increased, and these of the biceps femoris significantly decreased during the initial 100 msec phase of lifting. There were no differences in the activities of the upper trapezius, lumbar extensor muscles (L3, L5), and obliquus abdominis under the two conditions. There were also no differences in the lumbar angle when the case was lifted. The flexion angles of the hip, knee, and ankle significantly increased, and the lumbar spine moved closer to the case. Lifting posture was influenced by the head position. Advantages included being able to shift loads on the body from the lower back to the legs, to move the lumbar spine closer to the case, and to relatively increase the moment of lumbar extension. The weight of the head as it moved upward and back, and the weight of the rear part of the body as it moved downward and forward helped to maintain balance.

  20. Influences of the position of the head on posture while lifting.

    PubMed

    Ishida, H; Watanabe, S; Eguchi, A; Kobara, K

    2008-01-01

    In clinical training of some lower back pain patients, teaching them to control their lumbar lordosis during lifting may be difficult. Therefore, another effective method for lifting technique is required. In standing, head cannot move without some compensating postural adjustment. The purpose of this study was to examine the influence of head position on lifting posture. Fourteen healthy male volunteers (22.6 +/- 4.4 years old) lifted a case while maintaining two different head positions; a downward position and an upright position. In the upright position, activities of the latissimus dorsi and vastus lateralis significantly increased, and these of the biceps femoris significantly decreased during the initial 100 msec phase of lifting. There were no differences in the activities of the upper trapezius, lumbar extensor muscles (L3, L5), and obliquus abdominis under the two conditions. There were also no differences in the lumbar angle when the case was lifted. The flexion angles of the hip, knee, and ankle significantly increased, and the lumbar spine moved closer to the case. Lifting posture was influenced by the head position. Advantages included being able to shift loads on the body from the lower back to the legs, to move the lumbar spine closer to the case, and to relatively increase the moment of lumbar extension. The weight of the head as it moved upward and back, and the weight of the rear part of the body as it moved downward and forward helped to maintain balance. PMID:18551836

  1. Lift-Enhancing Tabs on Multielement Airfoils

    NASA Technical Reports Server (NTRS)

    Ross, James C.; Storms, Bruce L.; Carrannanto, Paul G.

    1995-01-01

    The use of flat-plate tabs (similar to Gurney flaps) to enhance the lift of multielement airfoils is extended here by placing them on the pressure side and near the trailing edge of the main element rather than just on the furthest downstream wing element. The tabs studied range in height from 0.125 to 1.25% of the airfoil reference chord. In practice, such tabs would be retracted when the high-lift system is stowed. The effectiveness of the concept was demonstrated experimentally and computationally on a two-dimensional NACA 63(sub 2)-215 Mod B airfoil with a single-slotted, 30%-chord flap. Both the experiments and computations showed that the tabs significantly increase the lift at a given angle of attack and the maximum lift coefficient of the airfoil. The computational results showed that the increased lift was a result of additional turning of the flow by the tab that reduced or eliminated now separation on the flap. The best configuration tested, a 0.5%-chord tab placed 0.5% chord upstream of the trailing edge of the main element, increased the maximum lift coefficient of the airfoil by 12% and the maximum lift-to-drag ratio by 40%.

  2. Rotating cylinder design as a lifting generator

    NASA Astrophysics Data System (ADS)

    Asrokin, Azharrudin; Rizal Ramly, Mohammad; Halim Ahmad, Abdul

    2013-12-01

    The airfoil shape of a wing has always been the design to generate lift. But few realized that a simple rotating cylinder can also create lift. However, the explanation and study of how a rotating cylinder creates lift are still complex. In remote area where it is difficult for air vehicle to access, the exploration and discovery of different configuration for design concept is rather important. Due to this reason, there is a need to think of a lift generator that can produce better lift (few fold better than conventional airfoil) at lower speed to take off in a short distance of time. This paper will explain the conditions and the design of such a wing using the rotating cylinder concept that will take off in a short time and requires little takeoff and landing strip. Spokes will be attached to the cylinder to force the surrounding air to rotate along with the cylinder. This will create a vortex that hastens the speed of the air on top of the cylinder and at the same time retarding the speed of air below the cylinder. From the results, the rougher surface cylinder produces more lift when rotating and also, higher speed rotation of the cylinder greatly changes the speed of the surrounding air, thus better lift.

  3. Roles of MAPK Pathway Activation During Cytokine Induction in BEAS-2B Cells Exposed to Fine World Trade Center (WTC) Dust

    PubMed Central

    Wang, Shang; Prophete, Colette; Soukup, Joleen M.; Chen, Lung-chi; Costa, Max; Ghio, Andrew; Qu, Qingshan; Chen, Haobin

    2014-01-01

    The World Trade Center (WTC) collapse on September 11, 2001 released copious amounts of particulate matter into the atmosphere of New York City. Follow-up studies on persons exposed to the dusts have revealed a severely increased rate for asthma and other respiratory illnesses. There have only been a few studies that have sought to discern the possible mechanisms underlying these untoward pathologies. In one study, an increased cytokine release was detected in cells exposed to WTC fine dusts (PM2.5 fraction or WTC2.5). However, the mechanism(s) for these increases has yet to be fully defined. Because activation of the MAPK signaling pathways is known to cause cytokine induction, the current study was undertaken to analyze the possible involvement of these pathways in any increased cytokine formation by lung epithelial cells (as BEAS-2B cells) exposed to WTC2.5. Our results showed that exposure to WTC2.5 for 5 hr increased IL-6 mRNA expression in BEAS-2B cells, as well as its protein levels in the culture media, in a dose-dependent manner. Besides IL-6, Cytokine Multiplex analyses revealed that formation of IL-8 and -10 was also elevated by the exposure. Both ERK and p38, but not JNK, signaling pathways were found to be activated in cells exposed to WTC2.5. Inactivation of ERK signaling pathways by PD98059 effectively blocked IL-6, -8, and -10 induction by WTC2.5; the p38 kinase inhibitor SB203580 significantly decreased induction of IL-8 and -10. Together, our data demonstrated activation of MAPK signaling pathway(s) likely played an important role in the WTC2.5-induced formation of several inflammatory (and, subsequently, anti-inflammatory) cytokines. The results are important in that they help to define one mechanism via which the WTC dusts may have acted to cause the documented increases in asthma and other inflammation-associated respiratory dysfunctions in the individuals exposed to the dusts released from the WTC collapse. PMID:20731619

  4. Electrostatic dust transport on the surfaces of airless bodies

    NASA Astrophysics Data System (ADS)

    Wang, X.; Schwan, J.; Hsu, H. W.; Horanyi, M.

    2015-12-01

    The surfaces of airless bodies are charged due to the exposure to solar wind plasma and UV radiation. Dust particles on the regolith of these surfaces can become charged, and may move and even get lofted due to electrostatic force. Electrostatic dust transport has been a long-standing problem that may be related to many observed phenomena on the surfaces of airless planetary bodies, including the lunar horizon glow, the dust ponds on asteroid Eros, the spokes in Saturn's rings, and more recently, the collection of dust particles ejected off Comet 67P, observed by Rosetta. In order to resolve these puzzles, a handful of laboratory experiments have been performed in the past and demonstrated that dust indeed moves and lifts from surfaces exposed to plasma. However, the exact mechanisms for the mobilization of dust particles still remain a mystery. Current charging models, including the so-called "shared charge model" and the charge fluctuation theory, will be discussed. It is found that neither of these models can explain the results from either laboratory experiments or in-situ observations. Recently, single dust trajectories were captured with our new dust experiments, enabling novel micro-scale investigations. The particles' initial launch speeds and size distributions are analyzed, and a new so-called "patched charge model" is proposed to explain our findings. We identify the role of plasma micro-cavities that are formed in-between neighboring dust particles. The emitted secondary or photo- electrons are proposed to be absorbed inside the micro-cavities, resulting in significant charge accumulation on the exposed patches of the surfaces of neighboring particles. The resulting enhanced Coulomb force (repulsion) between particles is likely the dominant force to mobilize and lift them off the surface. The role of other properties, including surface morphology, cohesion and photoelectron charging, will also be discussed.

  5. Uranium mill ore dust characterization

    SciTech Connect

    Knuth, R.H.; George, A.C.

    1980-11-01

    Cascade impactor and general air ore dust measurements were taken in a uranium processing mill in order to characterize the airborne activity, the degree of equilibrium, the particle size distribution and the respirable fraction for the /sup 238/U chain nuclides. The sampling locations were selected to limit the possibility of cross contamination by airborne dusts originating in different process areas of the mill. The reliability of the modified impactor and measurement techniques was ascertained by duplicate sampling. The results reveal no significant deviation from secular equilibrium in both airborne and bulk ore samples for the /sup 234/U and /sup 230/Th nuclides. In total airborne dust measurements, the /sup 226/Ra and /sup 210/Pb nuclides were found to be depleted by 20 and 25%, respectively. Bulk ore samples showed depletions of 10% for the /sup 226/Ra and /sup 210/Pb nuclides. Impactor samples show disequilibrium of /sup 226/Ra as high as +-50% for different size fractions. In these samples the /sup 226/Ra ratio was generally found to increase as particle size decreased. Activity median aerodynamic diameters of the airborne dusts ranged from 5 to 30 ..mu..m with a median diameter of 11 ..mu..m. The maximum respirable fraction for the ore dusts, based on the proposed International Commission on Radiological Protection's (ICRP) definition of pulmonary deposition, was < 15% of the total airborne concentration. Ore dust parameters calculated for impactor duplicate samples were found to be in excellent agreement.

  6. Modeling Europa's dust plumes

    NASA Astrophysics Data System (ADS)

    Southworth, B. S.; Kempf, S.; Schmidt, J.

    2015-12-01

    The discovery of Jupiter's moon Europa maintaining a probably sporadic water vapor plume constitutes a huge scientific opportunity for NASA's upcoming mission to this Galilean moon. Measuring properties of material emerging from interior sources offers a unique chance to understand conditions at Europa's subsurface ocean. Exploiting results obtained for the Enceladus plume, we simulate possible Europa plume configurations, analyze particle number density and surface deposition results, and estimate the expected flux of ice grains on a spacecraft. Due to Europa's high escape speed, observing an active plume will require low-altitude flybys, preferably at altitudes of 5-100 km. At higher altitudes a plume may escape detection. Our simulations provide an extensive library documenting the possible structure of Europa dust plumes, which can be quickly refined as more data on Europa dust plumes are collected.

  7. Dust Storm, Aral Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Aral Sea has shrunk to less than half its size since 1985. The Aral Sea receives little water (sometimes no water) from the two major rivers that empty into it-the Syr Darya and Amu Darya. Instead, the river water is diverted to support irrigation for the region's extensive cotton fields. Recently, water scarcity has increased due to a prolonged drought in Central Asia. As the Aral Sea recedes, its former sea bed is exposed. The Aral's sea bed is composed of fine sediments-including fertilizers and other agricultural chemicals-that are easily picked up by the region's strong winds, creating thick dust storms. The International Space Station crew observed and recorded a large dust storm blowing eastward from the Aral Sea in late June 2001. This image illustrates the strong coupling between human activities (water diversions and irrigation), and rapidly changing land, sea and atmospheric processes-the winds blow across the

  8. Dust Measurements in Tokamaks

    SciTech Connect

    Rudakov, D; Yu, J; Boedo, J; Hollmann, E; Krasheninnikov, S; Moyer, R; Muller, S; Yu, A; Rosenberg, M; Smirnov, R; West, W; Boivin, R; Bray, B; Brooks, N; Hyatt, A; Wong, C; Fenstermacher, M; Groth, M; Lasnier, C; McLean, A; Stangeby, P; Ratynskaia, S; Roquemore, A; Skinner, C; Solomon, W M

    2008-04-23

    Dust production and accumulation impose safety and operational concerns for ITER. Diagnostics to monitor dust levels in the plasma as well as in-vessel dust inventory are currently being tested in a few tokamaks. Dust accumulation in ITER is likely to occur in hidden areas, e.g. between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering resolves size of particles between 0.16-1.6 {micro}m in diameter; the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast-framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in 2D with a single camera or 3D using multiple cameras, but determination of particle size is problematic. In order to calibrate diagnostics and benchmark dust dynamics modeling, pre-characterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase of carbon atomic, C2 dimer, and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.

  9. Secondary lift for magnetically levitated vehicles

    DOEpatents

    Cooper, Richard K.

    1976-01-01

    A high-speed terrestrial vehicle that is magnetically levitated by means of magnets which are used to induce eddy currents in a continuous electrically conductive nonferromagnetic track to produce magnetic images that repel the inducing magnet to provide primary lift for the vehicle. The magnets are arranged so that adjacent ones have their fields in opposite directions and the magnets are spaced apart a distance that provides a secondary lift between each magnet and the adjacent magnet's image, the secondary lift being maximized by optimal spacing of the magnets.

  10. Dynamic analysis of plunger lift operations

    SciTech Connect

    Lea, J.F.

    1981-01-01

    Presented is a description of a dynamic model of plunger lift operations which, as opposed to previous methods of analysis. includes calculation of the plunger velocity as the plunger and liquid slug travel up the tubing. Also an analysis of plunger cycles in a high gas-liquid ratio well is presented to indicate the maximum rate of slug buildup, and the maximum casing pressure necessary to lift the plunger and accumulated liquids. The information presented allows a more detailed engineering approach to analyzing the performance of a plunger lifted well. Refs.

  11. Geometry program for aerodynamic lifting surface theory

    NASA Technical Reports Server (NTRS)

    Medan, R. T.

    1973-01-01

    A computer program that provides the geometry and boundary conditions appropriate for an analysis of a lifting, thin wing with control surfaces in linearized, subsonic, steady flow is presented. The kernel function method lifting surface theory is applied. The data which is generated by the program is stored on disk files or tapes for later use by programs which calculate an influence matrix, plot the wing planform, and evaluate the loads on the wing. In addition to processing data for subsequent use in a lifting surface analysis, the program is useful for computing area and mean geometric chords of the wing and control surfaces.

  12. Wingless Flight: The Lifting Body Story

    NASA Technical Reports Server (NTRS)

    Reed, R. Dale; Lister, Darlene (Editor); Huntley, J. D. (Editor)

    1997-01-01

    Wingless Flight tells the story of the most unusual flying machines ever flown, the lifting bodies. It is my story about my friends and colleagues who committed a significant part of their lives in the 1960s and 1970s to prove that the concept was a viable one for use in spacecraft of the future. This story, filled with drama and adventure, is about the twelve-year period from 1963 to 1975 in which eight different lifting-body configurations flew. It is appropriate for me to write the story, since I was the engineer who first presented the idea of flight-testing the concept to others at the NASA Flight Research Center. Over those twelve years, I experienced the story as it unfolded day by day at that remote NASA facility northeast of los Angeles in the bleak Mojave Desert. Benefits from this effort immediately influenced the design and operational concepts of the winged NASA Shuttle Orbiter. However, the full benefits would not be realized until the 1990s when new spacecraft such as the X-33 and X-38 would fully employ the lifting-body concept. A lifting body is basically a wingless vehicle that flies due to the lift generated by the shape of its fuselage. Although both a lifting reentry vehicle and a ballistic capsule had been considered as options during the early stages of NASA's space program, NASA initially opted to go with the capsule. A number of individuals were not content to close the book on the lifting-body concept. Researchers including Alfred Eggers at the NASA Ames Research Center conducted early wind-tunnel experiments, finding that half of a rounded nose-cone shape that was flat on top and rounded on the bottom could generate a lift-to-drag ratio of about 1.5 to 1. Eggers' preliminary design sketch later resembled the basic M2 lifting-body design. At the NASA Langley Research Center, other researchers toyed with their own lifting-body shapes. Meanwhile, some of us aircraft-oriented researchers at the, NASA Flight Research Center at Edwards Air

  13. Wind tunnel investigation of a high lift system with pneumatic flow control

    NASA Astrophysics Data System (ADS)

    Victor, Pricop Mihai; Mircea, Boscoianu; Daniel-Eugeniu, Crunteanu

    2016-06-01

    Next generation passenger aircrafts require more efficient high lift systems under size and mass constraints, to achieve more fuel efficiency. This can be obtained in various ways: to improve/maintain aerodynamic performance while simplifying the mechanical design of the high lift system going to a single slotted flap, to maintain complexity and improve the aerodynamics even more, etc. Laminar wings have less efficient leading edge high lift systems if any, requiring more performance from the trailing edge flap. Pulsed blowing active flow control (AFC) in the gap of single element flap is investigated for a relatively large model. A wind tunnel model, test campaign and results and conclusion are presented.

  14. Dust Devil Sediment Transport: From Lab to Field to Global Impact

    NASA Astrophysics Data System (ADS)

    Klose, Martina; Jemmett-Smith, Bradley C.; Kahanpää, Henrik; Kahre, Melinda; Knippertz, Peter; Lemmon, Mark T.; Lewis, Stephen R.; Lorenz, Ralph D.; Neakrase, Lynn D. V.; Newman, Claire; Patel, Manish R.; Reiss, Dennis; Spiga, Aymeric; Whelley, Patrick L.

    2016-07-01

    The impact of dust aerosols on the climate and environment of Earth and Mars is complex and forms a major area of research. A difficulty arises in estimating the contribution of small-scale dust devils to the total dust aerosol. This difficulty is due to uncertainties in the amount of dust lifted by individual dust devils, the frequency of dust devil occurrence, and the lack of statistical generality of individual experiments and observations. In this paper, we review results of observational, laboratory, and modeling studies and provide an overview of dust devil dust transport on various spatio-temporal scales as obtained with the different research approaches. Methods used for the investigation of dust devils on Earth and Mars vary. For example, while the use of imagery for the investigation of dust devil occurrence frequency is common practice for Mars, this is less so the case for Earth. Modeling approaches for Earth and Mars are similar in that they are based on the same underlying theory, but they are applied in different ways. Insights into the benefits and limitations of each approach suggest potential future research focuses, which can further reduce the uncertainty associated with dust devil dust entrainment. The potential impacts of dust devils on the climates of Earth and Mars are discussed on the basis of the presented research results.

  15. SMART-COMMIT Observations and Deep-Blue Retrievals of Saharan Dust Properties during NAMMA

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee; Hsu, N. Christina; Ji, Qiang; Jeong, Myeong-Jae

    2007-01-01

    Monsoon rainfalls sustain the livelihood of more than half of the world's population. The interaction between natural/anthropogenic aerosols, clouds, and precipitation is a critical mechanism that drives the water cycle and fresh water distribution. Analyses of the longterm trend of July-August precipitation anomaly for the last 50 years in the 20" century depict that the largest regional precipitation deficit occurs over the Sahel, where the monsoon water cycle plays an important role. Thus, it is of paramount importance to study how dust aerosols, as well as air pollution and smoke, influence monsoon variability. The NASA African Monsoon Multidisciplinary Activities (NAMMA) was conducted during the international AMMA Special Observation Period (SOP-3) of September 2006 to better comprehend the key attributes of the Saharan Air Layer (SAL) and how they evolve from the source regions to the Atlantic Ocean. The SAL occurs during the late spring through early fall and originates as a result of low-level convergence induced by heat lows over the Sahara that lifts hot, dry, dust laden air aloft into a well mixed layer that extends up to 500mb. This is crucial for understanding the impact of SAL on the key atmospheric processes that determine precipitation over West Africa and tropical cyclogenesis. Results obtained from the synergy of satellite (Deep- Blue) and surface (SMART-COMMIT) observations will be presented and discussed how the physical, optical and radiative properties of the dust in the SAL evolve from the continental to the marine environment.

  16. DUST TRANSPORT IN PROTOSTELLAR DISKS THROUGH TURBULENCE AND SETTLING

    SciTech Connect

    Turner, N. J.; Carballido, A.; Sano, T.

    2010-01-01

    We apply ionization balance and magnetohydrodynamical (MHD) calculations to investigate whether magnetic activity moderated by recombination on dust grains can account for the mass accretion rates and the mid-infrared spectra and variability of protostellar disks. The MHD calculations use the stratified shearing-box approach and include grain settling and the feedback from the changing dust abundance on the resistivity of the gas. The two-decade spread in accretion rates among solar-mass T Tauri stars is too large to result solely from variations in the grain size and stellar X-ray luminosity, but can plausibly be produced by varying these parameters together with the disk magnetic flux. The diverse shapes and strengths of the mid-infrared silicate bands can come from the coupling of grain settling to the distribution of the magnetorotational turbulence, through the following three effects. First, recombination on grains 1 mum or smaller yields a magnetically inactive dead zone extending more than two scale heights from the midplane, while turbulent motions in the magnetically active disk atmosphere overshoot the dead zone boundary by only about one scale height. Second, grains deep in the dead zone oscillate vertically in wave motions driven by the turbulent layer above, but on average settle at the rates found in laminar flow, so that the interior of the dead zone is a particle sink and the disk atmosphere will become dust-depleted unless resupplied from elsewhere. Third, with sufficient depletion, the dead zone is thinner and mixing dredges grains off the midplane. The last of these processes enables evolutionary signatures such as the degree of settling to sometimes decrease with age. The MHD results also show that the magnetic activity intermittently lifts clouds of small grains into the atmosphere. Consequently the photosphere height changes by up to one-third over timescales of a few orbits, while the extinction along lines of sight grazing the disk surface

  17. A Dynamic Fountain Model for Lunar Dust

    NASA Technical Reports Server (NTRS)

    Stubbs, T. J.; Vondrak, R. R.; Farrell, W. M.

    2005-01-01

    During the Apollo era of exploration it was discovered that sunlight was scattered at the terminators giving rise to horizon glow and streamers above the lunar surface. This was observed from the dark side of the Moon during sunset and sunrise by both surface landers and astronauts in orbit. These observations were quite unexpected, as the Moon was thought to be a pristine environment with a negligible atmosphere or exosphere. Subsequent investigations have shown that the sunlight was most likely scattered by electrostatically charged dust grains originating from the surface. It has since been demonstrated that this dust population could have serious implications for astronomical observations from the lunar surface. The lunar surface is electrostatically charged by the Moon s large-scale interaction with the local plasma environment and the photoemission of electrons due to solar ultra-violet (UV) light and X-rays. The like-charged surface and dust grains then act to repel each other, such that under certain conditions the dust grains are lifted above the surface. We present a dynamic fountain model which can explain how sub-micron dust is able to reach altitudes of up to approximately 100 km above the lunar surface. Previous static dust levitation models are most applicable to the heavier micron-sized grains in close proximity proximity to the surface, but they cannot explain the presence of extremely light grains at high altitudes. If we relax the static constraint applied to previous models, and instead assume that the grains are in constant motion (under the action of dynamic forces), a new picture emerges for the behavior of sub-micron lunar dust.

  18. Dust feed mechanism

    DOEpatents

    Milliman, Edward M.

    1984-01-01

    The invention is a dust feed device for delivery of a uniform supply of dust for long periods of time to an aerosolizing means for production of a dust suspension. The device utilizes at least two tandem containers having spiral brushes within the containers which transport the dust from a supply to the aerosolizer means.

  19. Dusty Structure Around Type-I Active Galactic Nuclei: Clumpy Torus Narrow-line Region and Near-nucleus Hot Dust

    NASA Astrophysics Data System (ADS)

    Mor, Rivay; Netzer, Hagai; Elitzur, Moshe

    2009-11-01

    We fitted Spitzer/IRS ~ 2-35 μm spectra of 26 luminous quasi-stellar objects in an attempt to define the main emission components. Our model has three major components: a clumpy torus, dusty narrow-line region (NLR) clouds, and a blackbody-like dust. The models utilize the clumpy torus of Nenkova et al. and are the first to allow its consistent check in type-I active galactic nuclei (AGNs). Single torus models and combined torus-NLR models fail to fit the spectra of most sources, but three-component models adequately fit the spectra of all sources. We present torus inclination, cloud distribution, covering factor, and torus mass for all sources and compare them with bolometric luminosity, black hole mass, and accretion rate. The torus mass is found to be correlated with the bolometric luminosity of the sources. Torus-covering factor may also be (anti-)correlated, if some possibly anomalous points are omitted. We find that a substantial amount of the ~2-7 μm radiation originates from a hot dust component, which is likely situated in the innermost part of the torus. The luminosity radiated by this component and its covering factor are comparable to those of the torus. We quantify the emission by the NLR clouds and estimate their distance from the center. The distances are ~700 times larger than the dust sublimation radius, and the NLR-covering factor is about 0.07. The total covering factor by all components is in good agreement with the known AGN type-I:type-II ratio.

  20. On the dust environment of comet C/2012 S1 (ISON) from 12 AU pre-perihelion to the end of its activity around perihelion

    SciTech Connect

    Moreno, F.; Pozuelos, F.; Aceituno, F. [Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s and others

    2014-08-20

    A Monte Carlo dust tail model has been applied to extract the dust environment parameters of the comet C/2012 S1 (ISON) from both Earth-based and SOHO LASCO C3 observations, performed from about six astronomical units (AU) inbound, to just after perihelion passage, when only a small portion of the original comet nucleus has survived in the form of a cloud of tiny particles. The early Afρ and image data are consistent with particle ejection from an extended active area located at latitudes 35°N to 90°N (for a prograde rotating nucleus), with the spin axis having a large obliquity (I ∼ 70°). This configuration nicely fits the early images and Afρ data until 3.9 AU inbound, when the emission should become isotropic in order to fit the data. The analysis of LASCO images reveals that, assuming an original nucleus of R{sub N} = 500 m with ρ = 1000 kg m{sup –3}, at least half of its mass was vaporized when the comet was at about 17 R {sub ☉} inbound. We conclude that at that time the nucleus suffered a cataclysmic fragmentation releasing a huge amount of material of 2.3 ×10{sup 11} kg, equivalent to a sphere of 380 m in radius with density 1000 kg m{sup –3}. The surviving material after perihelion passage consists of very small dust particles of 0.1-50 μm in radius with a total mass of just 6.7×10{sup 8} kg.

  1. Experimental determination of baseball spin and lift.

    PubMed

    Alaways, L W; Hubbard, M

    2001-05-01

    The aim of this study was to develop a new method for the determination of lift on spinning baseballs. Inertial trajectories of (a) ball surface markers during the first metre of flight and (b) the centre of mass trajectory near home-plate were measured in a pitch using high-speed video. A theoretical model was developed, incorporating aerodynamic Magnus-Robins lift, drag and cross forces, which predicts the centre of mass and marker trajectories. Parameters including initial conditions and aerodynamic coefficients were estimated iteratively by minimizing the error between predicted and measured trajectories. We compare the resulting lift coefficients and spin parameter values with those of previous studies. Lift on four-seam pitches can be as much as three times that of two-seam pitches, although this disparity is reduced for spin parameters greater than 0.4.

  2. Heavy Lift & Propulsion Technology (HL&PT)

    NASA Video Gallery

    Cris Guidi delivers a presentation from the Heavy Lift & Propulsion Technology (HL&PT) study team on May 25, 2010, at the NASA Exploration Enterprise Workshop held in Galveston, TX. The purpose of ...

  3. A Dust Devil Playground

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA02185 A Dust Devil Playground

    Dust Devil activity in this region between Brashear and Ross Craters is very common. Large regions of dust devil tracks surround the south polar region of Mars.

    Image information: VIS instrument. Latitude -55.2N, Longitude 244.2E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  4. Lifted Partially Premixed Flames in Microgravity

    NASA Technical Reports Server (NTRS)

    Lock, Andrew J.; Ganguly, Ranjan; Puri, Ishwar K.; Aggarwal, Suesh K.; Hegde, Uday

    2004-01-01

    Lifted Double and Triple flames are established in the UIC-NASA Partially Premixed microgravity rig. The flames examined in this paper are established above a coannular burner because its axisymmetric geometry allows for future implementation of other non-intrusive optical diagnostic techniques easily. Both burner-attached stable flames and lifted flames are established at normal and microgravity conditions in the drop tower facility.

  5. Liftings and stresses for planar periodic frameworks

    PubMed Central

    Borcea, Ciprian; Streinu, Ileana

    2015-01-01

    We formulate and prove a periodic analog of Maxwell’s theorem relating stressed planar frameworks and their liftings to polyhedral surfaces with spherical topology. We use our lifting theorem to prove deformation and rigidity-theoretic properties for planar periodic pseudo-triangulations, generalizing features known for their finite counterparts. These properties are then applied to questions originating in mathematical crystallography and materials science, concerning planar periodic auxetic structures and ultrarigid periodic frameworks. PMID:26973370

  6. Dust charging and transport on airless planetary bodies

    NASA Astrophysics Data System (ADS)

    Wang, X.; Schwan, J.; Hsu, H.-W.; Grün, E.; Horányi, M.

    2016-06-01

    We report on laboratory experiments to shed light on dust charging and transport that have been suggested to explain a variety of unusual phenomena on the surfaces of airless planetary bodies. We have recorded micron-sized insulating dust particles jumping to several centimeters high with an initial speed of ~0.6 m/s under ultraviolet illumination or exposure to plasmas, resulting in an equivalent height of ~0.11 m on the lunar surface that is comparable to the height of the so-called lunar horizon glow. Lofted large aggregates and surface mobilization are related to many space observations. We experimentally show that the emission and re-absorption of photoelectron and/or secondary electron at the walls of microcavities formed between neighboring dust particles below the surface are responsible for generating unexpectedly large negative charges and intense particle-particle repulsive forces to mobilize and lift off dust particles.

  7. Novice lifters exhibit a more kyphotic lifting posture than experienced lifters in straight-leg lifting.

    PubMed

    Riley, A E; Craig, T D; Sharma, N K; Billinger, S A; Wilson, S E

    2015-07-16

    As torso flexion and repetitive lifting are known risk factors for low back pain and injury, it is important to investigate lifting techniques that might reduce injury during repetitive lifting. By normalizing lumbar posture to a subject's range of motion (ROM), as a function of torso flexion, this research examined when subjects approached their range of motion limits during dynamic lifting tasks. For this study, it was hypothesized that experienced lifters would maintain a more neutral lumbar angle relative to their range of motion, while novice lifters would approach the limits of their lumbar ROM during the extension phase of a straight-leg lift. The results show a statistically significant difference in lifting patterns for these two groups supporting this hypothesis. The novice group maintained a much more kyphotic lumbar angle for both the flexion (74% of the lumbar angle ROM) and extension phases (86% of the lumbar angle ROM) of the lifting cycle, while the experienced group retained a more neutral curvature throughout the entire lifting cycle (37% of lumbar angle ROM in flexion and 48% of lumbar angle ROM in extension). By approaching the limits of their range of motion, the novice lifters could be at greater risk of injury by placing greater loads on the supporting soft tissues of the spine. Future research should examine whether training subjects to assume more neutral postures during lifting could indeed lower injury risks.

  8. Numerical modeling of the gas lift process in gas lift wells

    NASA Astrophysics Data System (ADS)

    Temirbekov, N. M.; Turarov, A. K.; Baigereyev, D. R.

    2016-06-01

    In this paper, one-dimensional and two-dimensional axisymmetric motion of gas, liquid and a gas-liquid mixture in a gas-lift well is studied. Numerical simulation of the one-dimensional model of gas-lift process is considered where the movement in a gas-lift well is described by partial differential equations of hyperbolic type. Difference schemes for the gas-lift model of the process are developed on a nonuniform grid condensing in subdomains with big gradients of the solution. The results of the proposed algorithm are illustrated on the example of a real well.

  9. Novice Lifters Exhibit A More Kyphotic Lifting Posture Than Experienced Lifters In Straight-Leg Lifting

    PubMed Central

    Riley, A.E.; Craig, T.D.; Sharma, N.K.; Billinger, S.A.; Wilson, S.E.

    2015-01-01

    As torso flexion and repetitive lifting are known risk factors for low back pain and injury, it is important to investigate lifting techniques that might reduce injury during repetitive lifting. By normalizing lumbar posture to a subject’s range of motion (ROM), as a function of torso flexion, this research examined when subjects approached their range of motion limits during dynamic lifting tasks. For this study, it was hypothesized that experienced lifters would maintain a more neutral lumbar angle relative to their range of motion, while novice lifters would approach the limits of their lumbar ROM during the extension phase of a straight-leg lift. The results show a statistically significant difference in lifting patterns for these two groups supporting this hypothesis. The novice group maintained a much more kyphotic lumbar angle for both the flexion (74% of the lumbar angle ROM) and extension phases (86% of the lumbar angle ROM) of the lifting cycle, while the experienced group retained a more neutral curvature throughout the entire lifting cycle (37% of lumbar angle ROM in flexion and 48% of lumbar angle ROM in extension). By approaching the limits of their range of motion, the novice lifters could be at greater risk of injury by placing greater loads on the supporting soft tissues of the spine. Future research should examine whether training subjects to assume more neutral postures during lifting could indeed lower injury risks. PMID:26077846

  10. A Method for Calculation of Hydrodynamic Lift for Submerged and Planing Rectangular Lifting Surfaces

    NASA Technical Reports Server (NTRS)

    Wadlin, Kenneth L.; Christopher, Kenneth W.

    1959-01-01

    A method is presented for the calculation of lift coefficients for rectangular lifting surfaces of aspect ratios from 0.125 to 10 operating at finite depths beneath the water surface, including the zero depth or planing condition. Theoretical values are compared with experimental values obtained at various depths of submergence with lifting surfaces of aspect ratios from 0.125 to 10. The method can also be applied to hydrofoils with dihedral. Lift coefficients computed by this method are in good agreement with existing experimental data for aspect ratios from 0.125 to 10 and dihedral angles up to 30 deg.

  11. A Method for Calculation of Hydrodynamic Lift for Submerged and Planing Rectangular Lifting Surfaces

    NASA Technical Reports Server (NTRS)

    Wadlin, Kenneth L; Christopher, Kenneth W

    1958-01-01

    A method is presented for the calculation of lift coefficients for rectangular lifting surfaces of aspect ratios from 0.125 to 10 operating at finite depths beneath the water surface, including the zero depth or planing condition. Theoretical values are compared with experimental values obtained at various depths of submergence with lifting surfaces of aspect ratios from 0.125 to 10. The method can also be applied to hydrofoils with dihedral. Lift coefficients computed by this method are in good agreement with existing experimental data for aspect ratios from 0.125 to 10 and dihedral angles up to 10 degrees.

  12. Lift and wakes of flying snakes

    NASA Astrophysics Data System (ADS)

    Krishnan, Anush; Socha, John J.; Vlachos, Pavlos P.; Barba, L. A.

    2014-03-01

    Flying snakes use a unique method of aerial locomotion: they jump from tree branches, flatten their bodies, and undulate through the air to produce a glide. The shape of their body cross-section during the glide plays an important role in generating lift. This paper presents a computational investigation of the aerodynamics of the cross-sectional shape. Two-dimensional simulations of incompressible flow past the anatomically correct cross-section of the species Chrysopelea paradisi show that a significant enhancement in lift appears at a 35° angle of attack, above Reynolds numbers 2000. Previous experiments on physical models also obtained an increased lift, at the same angle of attack. The flow is inherently three-dimensional in physical experiments, due to fluid instabilities, and it is thus intriguing that the enhanced lift also appears in the two-dimensional simulations. The simulations point to the lift enhancement arising from the early separation of the boundary layer on the dorsal surface of the snake profile, without stall. The separated shear layer rolls up and interacts with secondary vorticity in the near-wake, inducing the primary vortex to remain closer to the body and thus cause enhanced suction, resulting in higher lift.

  13. Survey of lift-fan aerodynamic technology

    NASA Technical Reports Server (NTRS)

    Hickey, David H.; Kirk, Jerry V.

    1993-01-01

    Representatives of NASA Ames Research Center asked that a summary of technology appropriate for lift-fan powered short takeoff/vertical landing (STOVL) aircraft be prepared so that new programs could more easily benefit from past research efforts. This paper represents one of six prepared for that purpose. The authors have conducted or supervised the conduct of research on lift-fan powered STOVL designs and some of their important components for decades. This paper will first address aerodynamic modeling requirements for experimental programs to assure realistic, trustworthy results. It will next summarize the results or efforts to develop satisfactory specialized STOVL components such as inlets and flow deflectors. It will also discuss problems with operation near the ground, aerodynamics while under lift-fan power, and aerodynamic prediction techniques. Finally, results of studies to reduce lift-fan noise will be presented. The paper will emphasize results from large scale experiments, where available, for reasons that will be brought out in the discussion. Some work with lift-engine powered STOVL aircraft is also applicable to lift-fan technology and will be presented herein. Small-scale data will be used where necessary to fill gaps.

  14. Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Crater wall dust avalanches in southern Arabia Terra.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 10.3, Longitude 24.5 East (335.5 West). 19 meter/pixel resolution.

  15. 14 CFR 25.697 - Lift and drag devices, controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Lift and drag devices, controls. 25.697....697 Lift and drag devices, controls. (a) Each lift device control must be designed so that the pilots....101(d). Lift and drag devices must maintain the selected positions, except for movement produced by...

  16. 14 CFR 25.697 - Lift and drag devices, controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Lift and drag devices, controls. 25.697....697 Lift and drag devices, controls. (a) Each lift device control must be designed so that the pilots....101(d). Lift and drag devices must maintain the selected positions, except for movement produced by...

  17. 49 CFR 178.812 - Top lift test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Top lift test. 178.812 Section 178.812... Top lift test. (a) General. The top lift test must be conducted for the qualification of all IBC... preparation for the top lift test. (1) Metal, rigid plastic, and composite IBC design types must be loaded...

  18. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or...

  19. 49 CFR 178.975 - Top lift test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Top lift test. 178.975 Section 178.975... Packagings § 178.975 Top lift test. (a) General. The top lift test must be conducted for the qualification of... the side. (b) Special preparation for the top lift test. (1) Metal and rigid plastic Large...

  20. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or...

  1. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or...

  2. 49 CFR 178.975 - Top lift test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Top lift test. 178.975 Section 178.975... Packagings § 178.975 Top lift test. (a) General. The top lift test must be conducted for the qualification of... the side. (b) Special preparation for the top lift test. (1) Metal and rigid plastic Large...

  3. 49 CFR 178.975 - Top lift test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Top lift test. 178.975 Section 178.975... Packagings § 178.975 Top lift test. (a) General. The top lift test must be conducted for the qualification of... the side. (b) Special preparation for the top lift test. (1) Metal and rigid plastic Large...

  4. 49 CFR 178.812 - Top lift test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Top lift test. 178.812 Section 178.812... Top lift test. (a) General. The top lift test must be conducted for the qualification of all IBC... preparation for the top lift test. (1) Metal, rigid plastic, and composite IBC design types must be loaded...

  5. 49 CFR 178.1050 - Top lift test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Top lift test. 178.1050 Section 178.1050... Containers § 178.1050 Top lift test. (a) General. The top lift test must be conducted for the qualification... for the top lift test. Flexible Bulk Container design types must be filled to six times the...

  6. 21 CFR 880.5500 - AC-powered patient lift.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false AC-powered patient lift. 880.5500 Section 880.5500... Devices § 880.5500 AC-powered patient lift. (a) Identification. An AC-powered lift is an electrically powered device either fixed or mobile, used to lift and transport patients in the horizontal or...

  7. 49 CFR 178.812 - Top lift test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Top lift test. 178.812 Section 178.812... Top lift test. (a) General. The top lift test must be conducted for the qualification of all IBC... preparation for the top lift test. (1) Metal, rigid plastic, and composite IBC design types must be loaded...

  8. 49 CFR 178.975 - Top lift test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... load being evenly distributed. (c) Test method. (1) A Large Packaging must be lifted in the manner for... opposite lifting devices, so that the hoisting forces are applied vertically for a period of five minutes; and (ii) Lifted by each pair of diagonally opposite lifting devices so that the hoisting forces...

  9. Plunger lift with wellhead compression boosts gas well production

    SciTech Connect

    Phillips, D.; Listiak, S.

    1996-10-01

    As gas wells are produced and reservoir pressures decline, it is often necessary to install wellhead compression to maintain production. As well decline continues, gas rate and velocity in the tubing will decrease to the point at which liquids cannot be lifted out of the wellbore. Even on compression, liquid loading will become a problem and production impairments will result. One remedy to the liquid loading problem is to install a plunger lift system coupled with compression. With new smart controllers, the plunger/compressor combination has been successfully installed on a number of wells. Following is a description of this type of system, and case histories of active installations in the San Juan basin.

  10. Incremental wind tunnel testing of high lift systems

    NASA Astrophysics Data System (ADS)

    Victor, Pricop Mihai; Mircea, Boscoianu; Daniel-Eugeniu, Crunteanu

    2016-06-01

    Efficiency of trailing edge high lift systems is essential for long range future transport aircrafts evolving in the direction of laminar wings, because they have to compensate for the low performance of the leading edge devices. Modern high lift systems are subject of high performance requirements and constrained to simple actuation, combined with a reduced number of aerodynamic elements. Passive or active flow control is thus required for the performance enhancement. An experimental investigation of reduced kinematics flap combined with passive flow control took place in a low speed wind tunnel. The most important features of the experimental setup are the relatively large size, corresponding to a Reynolds number of about 2 Million, the sweep angle of 30 degrees corresponding to long range airliners with high sweep angle wings and the large number of flap settings and mechanical vortex generators. The model description, flap settings, methodology and results are presented.

  11. Weight lifting and appendicular skeletal muscle mass among breast cancer survivors: a randomized controlled trial.

    PubMed

    Brown, Justin C; Schmitz, Kathryn H

    2015-06-01

    Low appendicular skeletal muscle mass (ASMM) is associated with premature mortality, hyperinsulinemia, frailty, disability, and low bone mineral density. We explored the potential efficacy of slowly progressive weight lifting to attenuate the decline of ASMM among breast cancer survivors by conducting a post hoc analysis of data from the Physical Activity and Lymphedema trial. Between October 2005 and August 2008, we conducted a single-blind, randomized controlled trial of twice weekly slowly progressive weight lifting or standard care among 295 non-metastatic breast cancer survivors. ASMM was quantified using dual-energy X-ray absorptiometry. Changes in ASMM were evaluated from baseline to 12 months between the weight lifting and control groups using repeated measures linear mixed effects regression models. Over 12 months, participants in the weight lifting group experienced attenuated declines in muscle mass compared to the control group, as reflected by relative ASMM (-0.01 ± 0.02 kg/m(2) vs -0.08 ± 0.03 kg/m(2); P = 0.041) and absolute ASMM (-0.02 ± 0.06 kg vs -0.22 ± 0.07 kg; P = 0.038), respectively. Weight lifting did not alter other body composition outcomes including body mass index, total body mass, body fat percentage, and fat mass compared to the control group. Weight lifting significantly increased upper and lower body muscle strength compared to the control group. The intervention was well tolerated with no serious adverse events related to weight lifting. Slowly progressive weight lifting attenuated the decline of ASMM among breast cancer survivors compared to standard care over 12 months. These data are hypothesis generating. Future studies should examine the efficacy of weight lifting to improve distal health outcomes among breast cancer survivors. PMID:25935584

  12. Weight Lifting and Appendicular Skeletal Muscle Mass among Breast Cancer Survivors: A Randomized Controlled Trial

    PubMed Central

    Brown, Justin C.; Schmitz, Kathryn H.

    2015-01-01

    Purpose Low appendicular skeletal muscle mass (ASMM) is associated with premature mortality, hyperinsulinemia, frailty, disability, and low bone mineral density. We explored the potential efficacy of slowly-progressive weight lifting to attenuate the decline of ASMM among breast cancer survivors by conducting a post hoc analysis of data from the Physical Activity and Lymphedema trial. Methods Between October 2005 and August 2008 we conducted a single-blind, randomized controlled trial of twice-weekly slowly-progressive weight lifting or standard care among 295 non-metastatic breast cancer survivors. ASMM was quantified using dual-energy x-ray absorptiometry. Changes in ASMM were evaluated from baseline to 12-months between the weight lifting and control groups using repeated-measures linear mixed-effects regression models. Results Over 12-months, participants in the weight lifting group experienced attenuated declines in muscle mass compared to the control group, as reflected by relative ASMM (−0.01±0.02 kg/m2 versus −0.08±0.03 kg/m2; P=0.041) and absolute ASMM (−0.02±0.06 kg versus −0.22±0.07 kg; P=0.038), respectively. Weight lifting did not alter other body composition outcomes including body mass index, total body mass, body fat percentage, and fat mass compared to the control group. Weight lifting significantly increased upper- and lower-body muscle strength compared to the control group. The intervention was well-tolerated with no serious adverse events related to weight lifting. Conclusions Slowly-progressive weight lifting attenuated the decline of ASMM among breast cancer survivors compared to standard care over 12-months. These data are hypothesis generating. Future studies should examine the efficacy of weight lifting to improve distal health outcomes among breast cancer survivors. PMID:25935584

  13. Automation of Workplace Lifting Hazard Assessment for Musculoskeletal Injury Prevention

    PubMed Central

    2014-01-01

    Objectives Existing methods for practically evaluating musculoskeletal exposures such as posture and repetition in workplace settings have limitations. We aimed to automate the estimation of parameters in the revised United States National Institute for Occupational Safety and Health (NIOSH) lifting equation, a standard manual observational tool used to evaluate back injury risk related to lifting in workplace settings, using depth camera (Microsoft Kinect) and skeleton algorithm technology. Methods A large dataset (approximately 22,000 frames, derived from six subjects) of simultaneous lifting and other motions recorded in a laboratory setting using the Kinect (Microsoft Corporation, Redmond, Washington, United States) and a standard optical motion capture system (Qualysis, Qualysis Motion Capture Systems, Qualysis AB, Sweden) was assembled. Error-correction regression models were developed to improve the accuracy of NIOSH lifting equation parameters estimated from the Kinect skeleton. Kinect-Qualysis errors were modelled using gradient boosted regression trees with a Huber loss function. Models were trained on data from all but one subject and tested on the excluded subject. Finally, models were tested on three lifting trials performed by subjects not involved in the generation of the model-building dataset. Results Error-correction appears to produce estimates for NIOSH lifting equation parameters that are more accurate than those derived from the Microsoft Kinect algorithm alone. Our error-correction models substantially decreased the variance of parameter errors. In general, the Kinect underestimated parameters, and modelling reduced this bias, particularly for more biased estimates. Use of the raw Kinect skeleton model tended to result in falsely high safe recommended weight limits of loads, whereas error-corrected models gave more conservative, protective estimates. Conclusions Our results suggest that it may be possible to produce reasonable estimates of

  14. Project Plan for Vertical Lift Machine

    SciTech Connect

    Ellsworth, G F

    2002-08-05

    This document describes the Project Plan for the development and manufacture of a Vertical Lift Machine. It is assumed by this project plan that the Vertical Lift Machine will be developed, designed, manufactured, and tested by a qualified vendor. LLNL will retain review and approval authority for each step given in this project plan. The Vertical Lift Machine is a single linear axis positioning device capable of lifting objects vertically at controlled rates and positioning them repeatedly at predetermined heights, in relation to other objects suspended from above, for high neutron multiplication experiments. Operation of the machine during the experiments is done remotely. The lift mechanism shall accommodate various platforms (tables) that support the objects to be raised. A frame will support additional subassemblies from above such that the lower subassembly can be raised close to and/or interface with those above. The structure must be stiff and motion of the table linear such that radial alignment is maintained (e.g. concentricity). The safe position for the Vertical Lift Machine is the lift mechanism fully retracted with the subassemblies fully separated. The machine shall reside in this position when not in use. It must return to this safe condition from any position upon failure of power sources, open safety interlocks, or operator initiated SCRAM. The Vertical Lift Machine shall have the capability of return to the safe position with no externally applied power. The Vertical Lift Machine shall have dual operator interfaces, one near the machine and another located in a remote control room. Conventional single key, key-lock switching shall be implemented to lock out the control interface not in use. The interface at the machine will be used for testing and ''dry running'' experimental setup(s) with inert subassemblies (i.e. Setup Mode). The remote interface shall provide full control and data recording capability (i.e. Assembly Mode). The control system

  15. Dust events, pulmonary diseases and immune system

    PubMed Central

    Esmaeil, Nafiseh; Gharagozloo, Marjan; Rezaei, Abbas; Grunig, Gabriele

    2014-01-01

    Incidences of sand storms have increased in recent years and there is evidence that these dusts can move across long distances. Sand dusts have different adverse effects on health, but one of the most important of them is pulmonary disease. After inhalation of dust, many dust particles are moved to the airways. Dust particles can be sensed by airways epithelial cells, activate macrophages, dendritic cells and innate immune cells and then initiate responses in various populations of specific immune cells such as T helper cells subsets (Th1, Th2, Th17), T cytotoxic cells and B cells. Initiation of inflammatory immune responses, activation of immune cells and releases of many cytokines, chemokines and other inflammatory molecules, have variable pathologic affects on lung in different respiratory diseases. Unfortunately control of desert dusts is more difficult than control of air pollution. For prevention and treatment of respiratory diseases that are caused by desert dusts, researchers need well-designed epidemiological studies, combined with analysis of the precise composition of sand dusts, and the precise mechanisms of the immune responses. Recognizing the exact cellular and molecular immune mechanisms would be very useful to find new approaches for treatment of desert dust associated pulmonary diseases. PMID:24660118

  16. Dynamics of Charged Dust Near Surfaces in Space

    NASA Astrophysics Data System (ADS)

    Colwell, Joshua; Horanyi, Mihaly; Sickafoose, Amanda; Robertson, Scott

    2002-11-01

    Objects in plasma, such as planetary bodies in the solar wind, charge to a floating potential determined by the balance between charging currents in the local plasma environment. In cases where secondary electron emission and photoemission are weak, objects will become negatively charged due to electron collection and will be surrounded by a plasma sheath. Solar ultraviolet radiation can produce a photoelectron sheath above the sunlit surface of airless planetary bodies. In both cases an electric field is present near the surface that can accelerate charged dust particles near the surface. Dust may be stably levitated if the electric force balances the gravitational force. Experiments in a plasma sheath have shown that particles can be stably levitated with surface potentials consistent with those expected on planetary surfaces. Our experiments have also shown that particles can be lifted off the surface by the electric field without any additional disturbance. This may explain the separation of dust from the surfaces of larger particles in Saturn's rings observed as 'spokes' by local plasma presumably generated by an impact. Observations of smooth deposits of regolith in crater bottoms on the asteroid 433 Eros by the NEAR spacecraft suggest a transport mechanism for regolith. Levitation of charged dust and transport in an inhomogeneous electric field is a possible explanation for the distribution of regolith on Eros and other asteroids. More generally, acceleration of charged dust in the near-surface sheath can lead to loss of fine-grained particles from objects with weak gravitational accelerations. We have carried out experiments on charging, levitation, and transport of dust in plasma and photoelectron sheaths. A tungsten filament beneath the surface plate creates the primary electrons that ionize gas in the chamber. When the surface is biased to a sufficiently high voltage (-40V to -80V), dust particles are lifted off the surface. Some of these particles

  17. Ice nucleation by soil dust compared to desert dust aerosols

    NASA Astrophysics Data System (ADS)

    Moehler, O.; Steinke, I.; Ullrich, R.; Höhler, K.; Schiebel, T.; Hoose, C.; Funk, R.

    2015-12-01

    A minor fraction of atmospheric aerosol particles, so-called ice-nucleating particles (INPs), initiates the formation of the ice phase in tropospheric clouds and thereby markedly influences the Earth's weather and climate systems. Whether an aerosol particle acts as an INP depends on its size, morphology and chemical compositions. The INP fraction of certain aerosol types also strongly depends on the temperature and the relative humidity. Because both desert dust and soil dust aerosols typically comprise a variety of different particles, it is difficult to assess and predict their contribution to the atmospheric INP abundance. This requires both accurate modelling of the sources and atmospheric distribution of atmospheric dust components and detailed investigations of their ice nucleation activities. The latter can be achieved in laboratory experiments and parameterized for use in weather and climate models as a function of temperature and particle surface area, a parameter called ice-nucleation active site (INAS) density. Concerning ice nucleation activity studies, the soil dust is of particular interest because it contains a significant fraction of organics and biological components, both with the potential for contributing to the atmospheric INP abundance at relatively high temperatures compared to mineral components. First laboratory ice nucleation experiments with a few soil dust samples indicated their INP fraction to be comparable or slightly enhanced to that of desert dust. We have used the AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud simulation chamber to study the immersion freezing ability of four different arable soil dusts, sampled in Germany, China and Argentina. For temperatures higher than about -20°C, we found the INP fraction of aerosols generated from these samples by a dry dispersion technique to be significantly higher compared to various desert dust aerosols also investigated in AIDA experiments. In this contribution, we

  18. In-situ dust measurements by a lunar lander

    NASA Astrophysics Data System (ADS)

    Srama, Ralf; Sternovsky, Zoltan; Horanyi, Mihaly; Gruen, Eberhard; Krueger, Harald; Laufer, Rene; Roeser, Hans-Peter; Postberg, Frank; Kempf, Sascha; Moragas-Klostermeyer, Georg; Mocker, Anna; Fiege, Katherina; Li, Yanwei

    2012-07-01

    Charged dust grains on the lunar surface impact our future exploration of the moon. Serious problems for exploration activities were revealed by the Apollo missions. Dust shows strong adhesion to equipment and clothes and makes breathing difficult within a spacecraft. The micron- and submicron sized grains are embedded in the lunar plasma environment and their physical properties determine their dynamics. The solar wind, UV light and shadows lead to temporal effects in plasma densities and dust grain charging states. The dust populations relevant for the processes on the surface are: interplanetary and interstellar dust, levitated dust and, especially, dust ejecta generated by primary impacts on the surface. A dust instrument on the surface shall distinguish the three populations and characterize their charging state, size, speed and directionality distribution. Dust measurements shall be performed in conjunction with surface plasma and surface electric field characterizations.

  19. Detection of anthropogenic dust using CALIPSO lidar measurements

    NASA Astrophysics Data System (ADS)

    Huang, J. P.; Liu, J. J.; Chen, B.; Nasiri, S. L.

    2015-10-01

    Anthropogenic dusts are those produced by human activities on disturbed soils, which are mainly cropland, pastureland, and urbanized regions, and are a subset of the total dust load which includes natural sources from desert regions. Our knowledge of anthropogenic dusts is still very limited due to a lack of data. To understand the contribution of anthropogenic dust to the total global dust load, it is important to identify it apart from total dust. In this study, a new technique for distinguishing anthropogenic dust from natural dust is proposed by using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) dust and planetary boundary layer (PBL) height retrievals along with a land use data set. Using this technique, the global distribution of dust is analyzed and the relative contribution of anthropogenic and natural dust sources to regional and global emissions are estimated. Results reveal that local anthropogenic dust aerosol due to human activity, such as agriculture, industrial activity, transportation, and overgrazing, accounts for about 25 % of the global continental dust load. Of these anthropogenic dust aerosols, more than 53 % come from semi-arid and semi-wet regions. Annual mean anthropogenic dust column burden (DCB) values range from 0.42 g m-2, with a maximum in India, to 0.12 g m-2, with a minimum in North America. A better understanding of anthropogenic dust emission will enable us to focus on human activities in these critical regions and with such knowledge we will be more able to improve global dust models and to explore the effects of anthropogenic emission on radiative forcing, climate change, and air quality in the future.

  20. Detection of anthropogenic dust using CALIPSO lidar measurements

    NASA Astrophysics Data System (ADS)

    Huang, J.; Liu, J.; Chen, B.; Nasiri, S. L.

    2015-04-01

    Anthropogenic dusts are those produced by human activities on disturbed soils, which are mainly cropland, pasture, and urbanized regions and are a subset of the total dust load which includes natural sources from desert regions. Our knowledge of anthropogenic dusts is still very limited due to a lack of data on source distribution and magnitude, and on their effect on radiative forcing which may be comparable to other anthropogenic aerosols. To understand the contribution of anthropogenic dust to the total global dust load and its effect on radiative transfer and climate, it is important to identify them from total dust. In this study, a new technique for distinguishing anthropogenic dust from natural dust is proposed by using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) dust and planetary boundary layer (PBL) height retrievals along with a land use dataset. Using this technique, the global distribution of dust is analyzed and the relative contribution of anthropogenic and natural dust sources to regional and global emissions are estimated. Results reveal that local anthropogenic dust aerosol due to human activity, such as agriculture, industrial activity, transportation, and overgrazing, accounts for about 25% of the global continental dust load. Of these anthropogenic dust aerosols, more than 53% come from semi-arid and semi-wet regions. Annual mean anthropogenic dust column burden (DCB) values range from 0.42 g m-2 with a maximum in India to 0.12 g m-2 with a minimum in North America. A better understanding of anthropogenic dust emission will enable us to focus on human activities in these critical regions and with such knowledge we will be better able to improve global dust models and to explore the effects of anthropogenic emission on radiative forcing, climate change and air quality in the future.

  1. Heavy Lift for Exploration: Options and Utilization

    NASA Technical Reports Server (NTRS)

    Creech, Steve; Sumrall, Phil

    2010-01-01

    Every study of exploration capabilities since the Apollo Program has recommended the renewal of a heavy lift launch capability for the United States. NASA is aggressively pursuing that capability. This paper will discuss several aspects of that effort and the potential uses for that heavy lift capability. The need for heavy lift was cited most recent in the findings of the Review of U.S. Human Space Flight Plans Committee. Combined with considerations of launch availability and on-orbit operations, the Committee finds that exploration will benefit from the availability of a heavy-lift vehicle, the report said. In addition, heavy lift would enable the launching of large scientific observatories and more capable deep-space missions. It may also provide benefit in national security applications. The most recent focus of NASA s heavy lift effort is the Ares V cargo launch vehicle, which is part of the Constellation Program architecture for human exploration beyond low Earth orbit (LEO). The most recent point-of-departure configuration of the Ares V was approved during the Lunar Capabilities concept Review (LCCR) in 2008. The Ares V first stage propulsion system consists of a core stage powered by six commercial liquid hydrogen/liquid oxygen (LH2/LOX) RS-68 engines, flanked by two 5.5-segment solid rocket boosters (SRBs) based on the 5-segment Ares I first stage. The boosters use the same Polybutadiene Acrylonitrile (PBAN) propellant as the Space Shuttle. Atop the core stage is the Earth departure stage (EDS), powered by a single J-2X upper stage engine based on the Ares I upper stage engine. The 33-foot-diameter payload shroud can enclose a lunar lander, scientific instruments, or other payloads. Since LCCR, NASA has continued to refine the design through several successive internal design cycles. In addition, NASA has worked to quantify the broad national consensus for heavy lift in ways that, to the extent possible, meet the needs of the user community.

  2. Recovery of DNA from latent fingerprint tape lifts archived against matte acetate.

    PubMed

    Steadman, Shelly A; Hoofer, Steven R; Geering, Sarah C; King, Stephanie; Bennett, Marc A

    2015-05-01

    This study was driven by court order to examine methods to remove, extract, and STR-type potential DNA entrapped between latent fingerprint lifting tape and matte acetate that was collected from a 1977 crime scene. Results indicate that recovery of appreciable quantities of DNA is more challenging once adhesive is attached to matte acetate cards and even more difficult when fixed following black powder enhancement. STR amplification of extracts from entrapped fingermarks collected following the dusting/lifting procedure did not produce robust profiles, and extraneous peaks not expressed by print donors were detected for some samples. A hearing was set to argue whether there was DNA remaining to be tested, and if so, whether that DNA could be exculpatory in this postconviction matter. The studies herein provided the basis for the court's decision to not require the testing.

  3. Biological activity of recombinant Der p 2, Der p 5 and Der p 7 allergens of the house-dust mite Dermatophagoides pteronyssinus.

    PubMed

    Lynch, N R; Thomas, W R; Garcia, N M; Di Prisco, M C; Puccio, F A; L'opez, R I; Hazell, L A; Shen, H D; Lin, K L; Chua, K Y

    1997-09-01

    Der p 2, Der p 5 and Der p 7 are three allergens of the house-dust mite Dermatophagoides pteronyssinus that have been cloned and expressed in Escherichia coli as fusion proteins with glutathione-S-transferase (GST). We showed that these recombinant allergens produced immediate hypersensitivity skin-test reactions in 70, 60 and 52% respectively of a group of mite-sensitive allergic patients who were strongly positive to whole mite extract (WME). Comparable positivities were found for serum levels of specific IgE antibody against these allergens, as measured by the radioallergosorbant test (RAST). Overall, for the group of allergic patients that we evaluated, the serum IgE antibody concentrations against Der p 2, 5 and 7 were calculated to represent about one third, one quarter and one fifth respectively of the levels measured against the WME. However, for some patients the activity determined against the separate allergens was far higher than that detected against the WME, thus indicating that the concentration of these can be limiting in the WME. We found no significant correlations between the RAST levels against Derp 2 and either Derp 5 or 7, and RAST-inhibition tests indicated a lack of cross-reactivity between Der p 2 and the other two allergens. In contrast, the RAST results revealed the existence of a significant immunological relationship between Der p 5 and 7. Although a certain degree of reactivity against the GST fusion partner was found in the allergic patients studied, this was not a significant influence in determining the positivity against the recombinant allergens. These results confirm the in vivo biological activity of recombinant Der p 2, 5 and 7, and indicate that whilst Der p 2 is undoubtedly a major mite allergen, both Der p 5 and 7 make important contributions toward the overall allergenic activity of house-dust mites. PMID:9303332

  4. Modeling Europa's Dust Plumes

    NASA Astrophysics Data System (ADS)

    Southworth, B.; Kempf, S.; Schmidt, J.

    2015-12-01

    The discovery of Europa maintaining a probably sporadic water vapor plume constitutes a huge scientific opportunity for NASA's upcoming mission to this Galilean moon. Measuring the properties of material emerging from interior sources offers a unique chance to understand conditions at Europa's subsurface ocean. Exploiting results obtained for the Enceladus plume, we adjust the ejection model by Schmidt et al. [2008] to the conditions at Europa. In this way, we estimate properties of a possible, yet unobserved dust component of the Europa plume. For a size-dependent speed distribution of emerging ice particles we use the model from Kempf et al. [2010] for grain dynamics, modified to run simulations of plumes on Europa. Specifically, we model emission from the two plume locations determined from observations by Roth et al. [2014] and also from other locations chosen at the closest approach of low-altitude flybys investigated in the Europa Clipper study. This allows us to estimate expected fluxes of ice grains on the spacecraft. We then explore the parameter space of Europa dust plumes with regard to particle speed distribution parameters, plume location, and spacecraft flyby elevation. Each parameter set results in a 3-dimensional particle density structure through which we simulate flybys, and a map of particle fallback ('snowfall') on the surface of Europa. Due to the moon's high escape speed, a Europa plume will eject few to no particles that can escape its gravity, which has several further consequences: (i) For given ejection velocity a Europa plume will have a smaller scale height, with a higher particle number densities than the plume on Enceladus, (ii) plume particles will not feed the diffuse Galilean dust ring, (iii) the snowfall pattern on the surface will be more localized about the plume location, and will not induce a global m = 2 pattern as seen on Enceladus, and (iv) safely observing an active plume will require low altitude flybys, preferably at 50

  5. Blade design trade-offs using low-lift airfoils for stall-regulated HAWTs

    SciTech Connect

    Giguere, P.; Selig, M.S.; Tangler, J.L.

    1999-11-01

    A systematic blade design study was conducted to explore the trade-offs in using low-lift airfoils for a 750-kilowatt stall-regulated wind turbine. Tip-region airfoils having a maximum-lift coefficient ranging from 0.7--1.2 were considered in this study, with the main objective of identifying the practical lower limit for the maximum-life coefficient. Blades were optimized for both maximum annual energy production and minimum cost of energy using a method that takes into account aerodynamic and structural considerations. The results indicate that the effect of the maximum-lift coefficient on the cost of energy is small with a slight advantage to the highest maximum lift coefficient airfoils for the tip-region of the blade become more desirable as machine size increases, provided the airfoils yield acceptable stall characteristics. The conclusions are applicable to large wind turbines that use passive or active stall to regulate peak power.

  6. Dust near luminous ultraviolet stars

    NASA Technical Reports Server (NTRS)

    Henry, Richard C.

    1993-01-01

    This report describes research activities related to the Infrared Astronomical Satellite (IRAS) sky survey. About 745 luminous stars were examined for the presence of interstellar dust heated by a nearby star. The 'cirrus' discovered by IRAS is thermal radiation from interstellar dust at moderate and high galactic latitudes. The IRAS locates the dust which must (at some level) scatter ultraviolet starlight, although it was expected that thermal emission would be found around virtually every star, most stars shown no detectable emission. And the emission found is not uniform. It is not that the star is embedded in 'an interstellar medium', but rather what is found are discrete clouds that are heated by starlight. An exception is the dearth of clouds near the very hottest stars, implying that the very hottest stars play an active role with respect to destroying or substantially modifying the dust clouds over time. The other possibility is simply that the hottest stars are located in regions lacking in dust, which is counter-intuitive. A bibliography of related journal articles is attached.

  7. Dust-induced radiative feedbacks in north China: A dust storm episode modeling study using WRF-Chem

    NASA Astrophysics Data System (ADS)

    Liu, Lixia; Huang, Xin; Ding, Aijun; Fu, Congbin

    2016-03-01

    Radiative forcing of dust aerosol and the radiative feedbacks on the planetary boundary layer (PBL) in North China during a typical Asian dust storm in the early April of 2011 was investigated by an online coupled meteorology-chemistry-aerosol model WRF-Chem. Dust-induced daily mean radiative forcing (RF) at the ground surface and in the atmosphere were estimated to be -21.1 W m-2 and 12.7 W m-2, respectively, over Gobi desert, and -13.1 W m-2 and 4.8 W m-2, respectively, in downwind region over the North China Plain (NCP). Comparatively, radiative perturbation on short-wave radiation was approximately twice that on long-wave radiation in magnitude. In the daytime, when solar radiation dominated, the surface cooling and atmospheric heating due to dust increased PBL stability, leading to reductions of PBL height (PBLH) about 90 m and decreases in wind speed up to 0.4 m s-1. On the contrary, the radiative forcing in terrestrial radiation caused an opposite response at night, especially in the downwind region. Although dust emission was repressed by weakened wind speed during daytime, the elevated PBLH along with larger deflation at night lifted more dust particles to higher altitude (by up to 75 m in average), which prolonged dust residence time in the atmosphere and further intensified dust loading in downwind areas. Taking dust radiative feedbacks into consideration notably narrowed gaps between model-predicted air temperature vertical profiles with corresponding observations, suggesting a significant importance of dust-radiation interaction in PBL meteorology during dust storms.

  8. Design of a portable powered seat lift

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce

    1993-01-01

    People suffering from degenerative hip or knee joints find sitting and rising from a seated position very difficult. These people can rely on large stationary chairs at home, but must ask others for assistance when rising from any other chair. An orthopedic surgeon identified to the MSFC Technology Utilization Office the need for development of a portable device that could perform a similar function to the stationary lift chairs. The MSFC Structural Development Branch answered the Technology Utilization Office's request for design of a portable powered seat lift. The device is a seat cushion that opens under power, lifting the user to near-standing positions. The largest challenge was developing a mechanism to provide a stable lift over the large range of motion needed, and fold flat enough to be comfortable to sit on. CAD 3-D modeling was used to generate complete drawings for the prototype, and a full-scale working model of the Seat lift was made based on the drawings. The working model is of low strength, but proves the function of the mechanism and the concept.

  9. Dust storm events over Delhi: verification of dust AOD forecasts with satellite and surface observations

    NASA Astrophysics Data System (ADS)

    Singh, Aditi; Iyengar, Gopal R.; George, John P.

    2016-05-01

    Thar desert located in northwest part of India is considered as one of the major dust source. Dust storms originate in Thar desert during pre-monsoon season, affects large part of Indo-Gangetic plains. High dust loading causes the deterioration of the ambient air quality and degradation in visibility. Present study focuses on the identification of dust events and verification of the forecast of dust events over Delhi and western part of IG Plains, during the pre-monsoon season of 2015. Three dust events have been identified over Delhi during the study period. For all the selected days, Terra-MODIS AOD at 550 nm are found close to 1.0, while AURA-OMI AI shows high values. Dust AOD forecasts from NCMRWF Unified Model (NCUM) for the three selected dust events are verified against satellite (MODIS) and ground based observations (AERONET). Comparison of observed AODs at 550 nm from MODIS with NCUM predicted AODs reveals that NCUM is able to predict the spatial and temporal distribution of dust AOD, in these cases. Good correlation (~0.67) is obtained between the NCUM predicted dust AODs and location specific observations available from AERONET. Model under-predicted the AODs as compared to the AERONET observations. This may be mainly because the model account for only dust and no anthropogenic activities are considered. The results of the present study emphasize the requirement of more realistic representation of local dust emission in the model both of natural and anthropogenic origin, to improve the forecast of dust from NCUM during the dust events.

  10. "Dust Devils": Gardening Agents on the Surface of Mars, and Hidden Hazards to Human Exploration?

    NASA Technical Reports Server (NTRS)

    Marshall, J.; Smith, P.; White, B.; Farrell, W.

    1999-01-01

    dust devils are to be expected in reasonable abundance. First, from a geological perspective, the vortices will act as "gardening" agents for the top few centimeters of entrainable material. Over time (hundreds of millions, or billions of years being available), they will cover the surface with scouring paths, and the grain sizes that can be lofted by a vortex probably extends over the whole sand to dust range. The depositional paths are, of course, much larger, so that vortex-induced deposition is more widespread than vortex-induced erosion, and will without doubt, affect the whole region in which the dust devils occur (this might explain why rocks at the Viking site seemed oddly capped with dust in a region apparently subject to general aeolian scouring). On Mars, the lift forces in dust devils might be less than on earth owing to the much thinner atmosphere, but this may be counterbalanced by lower gravity and greater vortex velocities. Certainly, when active, other aeolian phenomena on Mars --sand motion and dust storms, seem no less energetic and no less capable of lofting sediments than equivalent terrestrial aeolian phenomena. Every several years, within the current climatic regime, the surface of Mars is subject to light dust fall from global dust storms. Over time, this should develop a very uniform surface layer, with commensurate uniformity in grain size, mineralogy, albedo, color, and general spectroscopic properties. Dust devils will disturb this situation by continually mixing the surface dust with underlying layers, perhaps composed of silt and sand. This size mixing will also involve compositional mixing. After some years, the thin layer of dust that may be difficult to entrain alone, becomes progressively mixed with coarser materials that could reduce the general aeolian threshold of the soil. Certainly the continual disturbance by vorticity will prevent surface stabilization that may bind or indurate grains (caused by slow cementation or ice welding

  11. Allergies, asthma, and dust

    MedlinePlus

    ... much dust. Dust particles collect in fabrics and carpets. If you can, get rid of fabric or ... are covered in cloth. Replace wall-to-wall carpet with wood or other hard flooring. Since mattresses, ...

  12. Characterization of surface properties affecting the activity of the 'free silica' fraction of respirable dusts. Final report

    SciTech Connect

    Wallace, W.E.; Keane, M.J.

    1988-01-01

    A two-part study was conducted to investigate the surface properties of the quartz or 'free silica' fraction of respirable mine dusts. The degree of surface contamination of respirable quartz particles was studied using scanning electron microscopy with energy-dispersive x-ray analysis (SEM-EDX) to distinguish alumino/silicate and magnesium silicate surface occlusions from the silicate particles. By varying the electron-beam accelerating voltage, the depth of penetration could be reduced, so that the surface layer could be distinguished from the substrate material. Experiments were conducted on the relationship of measured SEM-EDX signal coming from the substrate to coating thickness and electron-beam accelerating voltage. In the second part, modifications were made of respirable-quartz-particle cytotoxicity by surface treatment. As measured by erythrocyte hemolysis and pulmonary macrophage release of lactate dehydrogenase in-vitro, respirable quartz cytotoxicity was neutralized by boiling in water in glass test tubes for 10 to 40 minutes. The membranolytic potential was reduced to near zero by boiling up to 10 milligrams of quartz per milliliter of water. Replacing the medium with fresh water midway through the boiling resulted in full detoxification. Preboiling the medium with silica reduced the effect. Detoxification persisted after mild drying at 110 C for 8 hours and persisted after 3 days of resuspension in water at room temperature.

  13. Unsteady lifting-line theory with applications

    NASA Technical Reports Server (NTRS)

    Ahmadi, A. R.; Widnall, S. E.

    1982-01-01

    Unsteady lifting-line theory is developed for a flexible unswept wing of large aspect ratio oscillating at low frequency in inviscid incompressible flow. The theory is formulated in terms of the acceleration potential and treated by the method of matched asymptotic expansions. The wing displacements are prescribed and the pressure field, airloads, and unsteady induced downwash are obtained in closed form. Sample numerical calculations are presented. The present work identifies and resolves errors in the unsteady lifting-line theory of James and points out a limitation in that of Van Holten. Comparison of the results of Reissner's approximate unsteady lifting-surface theory with those of the present work shows favorable agreement. The present work thus provides some formal justification for Reissner's ad hoc theory. For engineering purposes, the region of applicability of the theory in the reduced frequency-aspect ratio domain is identified approximately and found to cover most cases of practical interest.

  14. Coriolis effects enhance lift on revolving wings.

    PubMed

    Jardin, T; David, L

    2015-03-01

    At high angles of attack, an aircraft wing stalls. This dreaded event is characterized by the development of a leading edge vortex on the upper surface of the wing, followed by its shedding which causes a drastic drop in the aerodynamic lift. At similar angles of attack, the leading edge vortex on an insect wing or an autorotating seed membrane remains robustly attached, ensuring high sustained lift. What are the mechanisms responsible for both leading edge vortex attachment and high lift generation on revolving wings? We review the three main hypotheses that attempt to explain this specificity and, using direct numerical simulations of the Navier-Stokes equations, we show that the latter originates in Coriolis effects. PMID:25871040

  15. NASA Heavy Lift Rotorcraft Systems Investigation

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Yamauchi, Gloria K.; Watts, Michael E.

    2005-01-01

    The NASA Heavy Lift Rotorcraft Systems Investigation examined in depth several rotorcraft configurations for large civil transport, designed to meet the technology goals of the NASA Vehicle Systems Program. The investigation identified the Large Civil Tiltrotor as the configuration with the best potential to meet the technology goals. The design presented was economically competitive, with the potential for substantial impact on the air transportation system. The keys to achieving a competitive aircraft were low drag airframe and low disk loading rotors; structural weight reduction, for both airframe and rotors; drive system weight reduction; improved engine efficiency; low maintenance design; and manufacturing cost comparable to fixed-wing aircraft. Risk reduction plans were developed to provide the strategic direction to support a heavy-lift rotorcraft development. The following high risk areas were identified for heavy lift rotorcraft: high torque, light weight drive system; high performance, structurally efficient rotor/wing system; low noise aircraft; and super-integrated vehicle management system.

  16. Coriolis effects enhance lift on revolving wings.

    PubMed

    Jardin, T; David, L

    2015-03-01

    At high angles of attack, an aircraft wing stalls. This dreaded event is characterized by the development of a leading edge vortex on the upper surface of the wing, followed by its shedding which causes a drastic drop in the aerodynamic lift. At similar angles of attack, the leading edge vortex on an insect wing or an autorotating seed membrane remains robustly attached, ensuring high sustained lift. What are the mechanisms responsible for both leading edge vortex attachment and high lift generation on revolving wings? We review the three main hypotheses that attempt to explain this specificity and, using direct numerical simulations of the Navier-Stokes equations, we show that the latter originates in Coriolis effects.

  17. Coriolis effects enhance lift on revolving wings

    NASA Astrophysics Data System (ADS)

    Jardin, T.; David, L.

    2015-03-01

    At high angles of attack, an aircraft wing stalls. This dreaded event is characterized by the development of a leading edge vortex on the upper surface of the wing, followed by its shedding which causes a drastic drop in the aerodynamic lift. At similar angles of attack, the leading edge vortex on an insect wing or an autorotating seed membrane remains robustly attached, ensuring high sustained lift. What are the mechanisms responsible for both leading edge vortex attachment and high lift generation on revolving wings? We review the three main hypotheses that attempt to explain this specificity and, using direct numerical simulations of the Navier-Stokes equations, we show that the latter originates in Coriolis effects.

  18. Another solid rocket booster is lifted at the tower at LP17A, CCAS

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A fourth and final Solid Rocket Booster, to be mated with a Boeing Delta II rocket, starts its lift up the tower at Pad 17A, Cape Canaveral Air Station. The rocket will carry the Stardust satellite into space for a close encounter with the comet Wild 2 in January 2004. Using a medium called aerogel, Stardust will capture comet particles flying off the nucleus of the comet, plus collect interstellar dust for later analysis. The collected samples will return to Earth in a Sample Return Capsule to be jettisoned as Stardust swings by Earth in January 2006. Stardust is scheduled to be launched on Feb. 6, 1999.

  19. Evaluation of dioxin-like activities in settled house dust from Vietnamese E-waste recycling sites: relevance of polychlorinated/brominated dibenzo-p-dioxin/furans and dioxin-like PCBs.

    PubMed

    Tue, Nguyen M; Suzuki, Go; Takahashi, Shin; Isobe, Tomohiko; Trang, Pham T K; Viet, Pham H; Tanabe, Shinsuke

    2010-12-01

    Few studies have investigated the human exposure to the ensemble of dioxin-related compounds (DRCs) released from uncontrolled e-waste recycling, especially from a toxic effect standpoint. This study evaluated the TCDD toxic equivalents (TEQs) in persistent extracts of settled house dust from two Vietnamese e-waste recycling sites (EWRSs) using the Dioxin-Responsive Chemically Activated LUciferase gene eXpression assay (DR-CALUX), combined with chemical analysis of PCDD/Fs, DL-PCBs, PBDD/Fs, and monobromo PCDD/Fs to determine their TEQ contribution. The CALUX-TEQ levels in house dust ranged from 370 to 1000 pg g(-1) in the EWRSs, approximately 3.5-fold higher than in the urban control site. In EWRS house dust, the concentrations of the unregulated PBDFs were 7.7-63 ng g(-1), an order of magnitude higher than those of regulated DRCs (PCDD/Fs and DL-PCBs), and PBDFs were also principal CALUX-TEQ contributors (4.2-22%), comparable to PCDD/Fs (8.1-29%). The CALUX-TEQ contribution of DRCs varied, possibly depending on thermal processing activities (higher PCDD/F-TEQs) and PBDE content in the waste (higher PBDF-TEQs). However, the percentage of unknown dioxin-like activities was high in all dust samples, indicating large contribution from unidentified DRCs and/or synergy among contaminants. Estimates of TEQ intake from dust ingestion suggest that children in the EWRSs may be adversely affected by DRCs from dust.

  20. What Are the Origins of Detached Layers of Dust on Mars ? Investigation with Global Climate Model

    NASA Astrophysics Data System (ADS)

    Bertrand, T.; Spiga, A.; Forget, F.

    2014-12-01

    The climate on Mars is strongly controlled by the amount of dust lifted and transported in the atmosphere, which causes fluctuations of air opacity and affects temperatures and winds. Recently, observations of the vertical dust distribution of the Martian atmosphere by the Mars Climate Sounder on board the Mars Reconnaissance Orbiter revealed a phenomenon which is still poorly understood: the formation of detached layers of dust. These detached layers, also confirmed by the Thermal Emission Spectrometer on-board the Mars Global Surveyor, reside above the planetary boundary layer typically at altitudes between 20 and 40 km and have been mostly observed at low latitudes. These detached layers of dust are not reproduced by Global Climate Models (GCM) and different atmospheric processes are discussed and can be combined to explain their origin, such as small-scale lifting, upslope topographic winds, scavenging by water ice clouds, dust storms… Here we use the Martian GCM developed at the Laboratoire de Météorologie Dynamique (LMD) to simulate the formation of detached layers of dust. To start, we developed a new implementation of the water cycle, taking into account nucleation on dust particles, ice particle growth, and scavenging of dust particles due to the condensation of ice. However, this method didn't yield to satisfying results in the GCM. Then, we performed the parameterization in the GCM of the so-called "rocket dust storms", governed by deep convection and able to inject dust at high altitudes in the Martian troposphere. By coupling this new parameterization with general circulation of the GCM, we succeed to model detached layers of dust. Here we present this parameterization and we discuss about the spatial and temporal variability of the detached layers of dust, in comparison with observations.

  1. Coupling the Mars Dust and Water Cycles: Investigating the Role of Clouds in Controlling the Vertical Distribution of Dust During N. H. Summer

    NASA Technical Reports Server (NTRS)

    Kahre, M. A.; Haberle, R. M.; Hollingsworth, J. L.; Wilson, R. J.

    2014-01-01

    The dust cycle is critically important for the current climate of Mars. The radiative effects of dust impact the thermal and dynamical state of the atmosphere (Gierasch and Goody, 1968; Haberle et al., 1982; Zurek et al., 1992). Although dust is present in the Martian atmosphere throughout the year, the level of dustiness varies with season. The atmosphere is generally the dustiest during northern fall and winter and the least dusty during northern spring and summer (Smith, 2004). Dust particles are lifted into the atmosphere by dust storms that range in size from meters to thousands of kilometers across (Cantor et al., 2001). During some years, regional storms combine to produce hemispheric or planet encircling dust clouds that obscure the surface and raise atmospheric temperatures by as much as 40 K (Smith et al., 2002). Key recent observations of the vertical distribution of dust indicate that elevated layers of dust exist in the tropics and sub-tropics throughout much of the year (Heavens et al., 2011). These observations have brought particular focus on the processes that control the vertical distribution of dust in the Martian atmosphere. The goal of this work is to further our understanding of how clouds in particular control the vertical distribution of dust, particularly during N. H. spring and summer

  2. Frequency response of lift control in Drosophila.

    PubMed

    Graetzel, Chauncey F; Nelson, Bradley J; Fry, Steven N

    2010-11-01

    The flight control responses of the fruitfly represent a powerful model system to explore neuromotor control mechanisms, whose system level control properties can be suitably characterized with a frequency response analysis. We characterized the lift response dynamics of tethered flying Drosophila in presence of vertically oscillating visual patterns, whose oscillation frequency we varied between 0.1 and 13 Hz. We justified these measurements by showing that the amplitude gain and phase response is invariant to the pattern oscillation amplitude and spatial frequency within a broad dynamic range. We also showed that lift responses are largely linear and time invariant (LTI), a necessary condition for a meaningful analysis of frequency responses and a remarkable characteristic given its nonlinear constituents. The flies responded to increasing oscillation frequencies with a roughly linear decrease in response gain, which dropped to background noise levels at about 6 Hz. The phase lag decreased linearly, consistent with a constant reaction delay of 75 ms. Next, we estimated the free-flight response of the fly to generate a Bode diagram of the lift response. The limitation of lift control to frequencies below 6 Hz is explained with inertial body damping, which becomes dominant at higher frequencies. Our work provides the detailed background and techniques that allow optomotor lift responses of Drosophila to be measured with comparatively simple, affordable and commercially available techniques. The identification of an LTI, pattern velocity dependent, lift control strategy is relevant to the underlying motion computation mechanisms and serves a broader understanding of insects' flight control strategies. The relevance and potential pitfalls of applying system identification techniques in tethered preparations is discussed. PMID:20462877

  3. Frequency response of lift control in Drosophila.

    PubMed

    Graetzel, Chauncey F; Nelson, Bradley J; Fry, Steven N

    2010-11-01

    The flight control responses of the fruitfly represent a powerful model system to explore neuromotor control mechanisms, whose system level control properties can be suitably characterized with a frequency response analysis. We characterized the lift response dynamics of tethered flying Drosophila in presence of vertically oscillating visual patterns, whose oscillation frequency we varied between 0.1 and 13 Hz. We justified these measurements by showing that the amplitude gain and phase response is invariant to the pattern oscillation amplitude and spatial frequency within a broad dynamic range. We also showed that lift responses are largely linear and time invariant (LTI), a necessary condition for a meaningful analysis of frequency responses and a remarkable characteristic given its nonlinear constituents. The flies responded to increasing oscillation frequencies with a roughly linear decrease in response gain, which dropped to background noise levels at about 6 Hz. The phase lag decreased linearly, consistent with a constant reaction delay of 75 ms. Next, we estimated the free-flight response of the fly to generate a Bode diagram of the lift response. The limitation of lift control to frequencies below 6 Hz is explained with inertial body damping, which becomes dominant at higher frequencies. Our work provides the detailed background and techniques that allow optomotor lift responses of Drosophila to be measured with comparatively simple, affordable and commercially available techniques. The identification of an LTI, pattern velocity dependent, lift control strategy is relevant to the underlying motion computation mechanisms and serves a broader understanding of insects' flight control strategies. The relevance and potential pitfalls of applying system identification techniques in tethered preparations is discussed.

  4. Pulmonary retention of coal dusts

    SciTech Connect

    Morrow, P.E.; Gibb, F.R.; Beiter, H.; Amato, F.; Yuile, C.; Kilpper, R.W.

    1980-01-01

    The principal objectives of this study were: to determine, quantitatively, coal dust retention times in the dog lung; to test the appropriateness of a pulmonary retention model which incorporates first order rate coefficients obtained from in vitro and in vivo experiments on neutron-activated coal; to acquire a temporal description of the pulmonary disposition of the retained coal dust, and to compare the behavior of two different Pennsylvania coals in the foregoing regards. The principal findings include: retention half-times for both coals of approximately 2 years following single, hour-long exposures; a vivid association of the retained coal dust with the pulmonic lymphatics; and a general validation of the retention model.

  5. Desert Dust and Monsoon Rain

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Kim, Kyu-Myong

    2014-01-01

    For centuries, inhabitants of the Indian subcontinent have know that heavy dust events brought on by strong winds occur frequently in the pre-monsoon season, before the onset of heavy rain. Yet scientists have never seriously considered the possibility that natural dust can affect monsoon rainfall. Up to now, most studies of the impacts of aerosols on Indian monsoon rainfall have focused on anthropogenic aerosols in the context of climate change. However, a few recent studies have show that aerosols from antropogenic and natural sources over the Indian subcontinent may affect the transition from break to active monsoon phases on short timescales of days to weeks. Writing in Nature Geoscience, Vinoj and colleagues describe how they have shown that desert dust aerosols over the Arabian Sea and West Asia can strenghten the summer monsoon over the Indial subcontinent in a matter of days.

  6. [Anesthetic maintenance during circular face lifting].

    PubMed

    Parshin, V I; Pastukhova, N K

    2010-01-01

    The paper deals with the specific features of anesthetic maintenance (ketamine, diprivan, dormicum, perfalgan, promedol) during circular face lifting without artificial ventilation. All intravenous anesthesia procedures have yielded good results. Narcotic analgesics may be removed from the anesthetic maintenance scheme, ruling out the necessity of their licensing, storing, and recording. The use of perfalgan causes no hallucinogenic reactions and offers the optimum level of anesthesia. During face lifting, 2.3 +/- 0.6-hour anesthesia with spontaneous breathing is possible, safe, and warranted. PMID:20524331

  7. Feasibility study of the dual-chamber SMART (SMA ReseTtable) lift device

    NASA Astrophysics Data System (ADS)

    Luntz, Jonathan E.; Brei, Diann; Ypma, Joe; Young, Jonathan R.; Radice, Joshua; Johnson, Nancy L.; Browne, Alan L.; Strom, Kenneth A.

    2007-04-01

    Pedestrian protection is a major focus of automotive crashworthiness with new regulations taking effect worldwide. While there are many approaches to reducing the head-injury-criteria (HIC), a leading approach is to actively lift the hood to increase the crush distance to rigid underhood components. Most current lift devices are single-use, requiring the hood to be manually returned to a drivable position, and may damage the hood during lift due to inappropriate lift rates. This paper addresses these issues with an alternative approach using stored energy marrying conventional (pneumatic) and smart materials (Shape Memory Alloy) actuation. The SMART (SMA ReseTtable) hood lift device comprises a dual chamber cylinder which releases stored pneumatic energy via an ultra-fast SMA exhaust valve, raising a piston attached to the hood. The device can be automatically reset and rearmed through pressurization of the chambers and the energy dissipated for service by evacuating both chambers. This approach is unique in that several design parameters such as pressure and valve opening/timing profile can be altered in the field to compensate for temperature, added mass (such as snow) or platform changes. This paper presents the concept of this device and the parametric design of the pneumatic cylinder and valve orifice based on an analytical performance model. Two valve concepts are presented: direct and indirect, where the direct valve is simpler and more controllable, but the indirect valve can provide larger orifices (and therefore faster lift times) with reduced actuation requirements. Using a combination of analytical model-based and experimental methods, the SMART lift device with each valve approach was designed, and a full-scale prototype built and experimentally characterized validating the model and successfully demonstrating feasibility of each system to meet and exceed the pedestrian protection specifications. This new set of technologies enables the hood lift

  8. Lower-limb extensor power and lifting characteristics in disabled elders.

    PubMed

    Dancewicz, Teresa M; Krebs, David E; McGibbon, Chris A

    2003-01-01

    Few reports address lifting in disabled elders. Resistance training may facilitate function by improving coordination and muscular recruitment in common lifting tasks. Subjects were considered "functionally limited" if they reported a limitation in at least 1 of 9 possible functional areas listed on the Short-Form Health Survey physical function scale (SF-36), excluding the vigorous activity item. Eighty-nine functionally limited elders (60.3 to 89.8 years old) consented to participate in an intervention trial consisting of a 6-month in-home video-facilitated resistance exercise program using elastic bands. Biomechanical variables (leg extensor power, work, squared jerk), temporal outcomes (lift time and time to peak leg powers), and leg extensor strength were analyzed with the use of analysis of variance (ANOVA) between the (1) experimental group versus control group and the (2) subgroup of the weakest third of subjects (pretest leg extensor strength as percent of body weight [BW]). The experimental group had significant improvements in strength in knee extension (16.7%) and hip extension (20.5%). Resistance-trained weak subjects significantly increased hip extension strength compared to controls. A trend toward improved performance in lifting--decreased total lift time--was noted in the resistance-trained subjects. Significant correlations were found between total leg extension power, total leg extension strength, total work, and lift time. Resistance-trained disabled elders demonstrated strength benefits and several trends consistent with improved coordination and more efficient lifting. Leg-muscle power was related to better functional performance in lifting.

  9. Niamey Dust Observations

    DOE Data Explorer

    Flynn, Connor

    2008-10-01

    Niamey aerosol are composed of two main components: dust due to the proximity of the Sahara Desert, and soot from local and regional biomass burning. The purpose of this data product is to identify when the local conditions are dominated by the dust component so that the properties of the dust events can be further studied.

  10. Middle East Dust

    Atmospheric Science Data Center

    2013-04-16

    ... (nadir) camera. Here only some of the dust over eastern Syria and southeastern Turkey can be discerned. The dust is much more obvious ... October 18, 2002 - A large dust plume extends across Syria and Turkey. project:  MISR category:  ...

  11. China Dust and Sand

    Atmospheric Science Data Center

    2013-04-16

    ... article title:  Dust and Sand Sweep Over Northeast China     View Larger Image ... these views of the dust and sand that swept over northeast China on March 10, 2004. Information on the height of the dust and an ...

  12. Dust in the Universe

    ERIC Educational Resources Information Center

    Hemenway, Mary Kay; Armosky, Brad J.

    2004-01-01

    Space is seeming less and less like empty space as new discoveries and reexaminations fill in the gaps. And, ingenuity and technology, like the Spitzer Space Telescope, is allowing examination of the far reaches of the Milky Way and beyond. Even dust is getting its due, but not the dust everyone is familiar with. People seldom consider the dust in…

  13. Saharan dust deposition in the Carpathian Basin and its possible effects on interglacial soil formation

    NASA Astrophysics Data System (ADS)

    Varga, György; Cserháti, Csaba; Kovács, János; Szalai, Zoltán

    2016-09-01

    Several hundred tons of windblown dust material are lifted into the atmosphere and are transported every year from Saharan dust source areas towards Europe having an important climatic and other environmental effect also on distant areas. According to the systematic observations of modern Saharan dust events, it can be stated that dust deflated from North African source areas is a significant constituent of the atmosphere of the Carpathian Basin and Saharan dust deposition events are identifiable several times in a year. Dust episodes are connected to distinct meteorological situations, which are also the determining factors of the different kinds of depositional mechanisms. By using the adjusted values of dust deposition simulations of numerical models, the annual Saharan dust flux can be set into the range of 3.2-5.4 g/m2/y. Based on the results of past mass accumulation rates calculated from stratigraphic and sedimentary data of loess-paleosol sequences, the relative contribution of Saharan dust to interglacial paleosol material was quantified. According to these calculations, North African exotic dust material can represent 20-30% of clay and fine silt-sized soil components of interglacial paleosols in the Carpathian Basin. The syngenetic contribution of external aeolian dust material is capable to modify physicochemical properties of soils and hereby the paleoclimatic interpretation of these pedogene stratigraphic units.

  14. Observing object lifting errors modulates cortico-spinal excitability and improves object lifting performance.

    PubMed

    Buckingham, Gavin; Wong, Jeremy D; Tang, Minnie; Gribble, Paul L; Goodale, Melvyn A

    2014-01-01

    Observing the actions of others has been shown to modulate cortico-spinal excitability and affect behaviour. However, the sensorimotor consequences of observing errors are not well understood. Here, participants watched actors lift identically weighted large and small cubes which typically elicit expectation-based fingertip force errors. One group of participants observed the standard overestimation and underestimation-style errors that characterise early lifts with these cubes (Error video--EV). Another group watched the same actors performing the well-adapted error-free lifts that characterise later, well-practiced lifts with these cubes (No error video--NEV). We then examined actual object lifting performance in the subjects who watched the EV and NEV. Despite having similar cognitive expectations and perceptions of heaviness, the group that watched novice lifters making errors themselves made fewer overestimation-style errors than those who watched the expert lifts. To determine how the observation of errors alters cortico-spinal excitability, we measured motor evoked potentials in separate group of participants while they passively observed these EV and NEV. Here, we noted a novel size-based modulation of cortico-spinal excitability when observing the expert lifts, which was eradicated when watching errors. Together, these findings suggest that individuals' sensorimotor systems are sensitive to the subtle visual differences between observing novice and expert performance.

  15. Dust and Ocean Plants

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Adding iron to the diet of marine plant life has been shown in shipboard experiments to boost the amount of carbon-absorbing phytoplankton in certain parts of the world's oceans. A new study promises to give scientists their first global picture of the extent of these unique 'iron-limited' ocean regions, an important step in understanding how the ocean's biology controls the flow of carbon between the atmosphere and the ocean. The new study by researchers at NASA's Goddard Space Flight Center and the Department of Energy's Oak Ridge National Laboratory was presented at the American Geophysical Union's annual meeting in San Francisco on Friday, Dec. 15, 2000. Oceanic phytoplankton remove nearly as much carbon from the atmosphere each year as all land-based plants. Identifying the location and size of nutrient-limited areas in the open ocean has challenged oceanographers for nearly a century. The study pinpointed iron-limited regions by seeing which phytoplankton-rich areas of the world's oceans were also areas that received iron from wind-blown dust. In this map, areas with high levels of chlorophyll from phytoplankton and high levels of dust deposition (high correlation coefficients) are indicated in dark brown. Dust deposition was calculated by a 3-year modelled climatology for the years 1996-1998. The chlorophyll measurements are from 1998 observations from the SeaWiFS (Sea-viewing Wide Field-of-view Sensor) instrument on the OrbView-2 satellite. 'Global, satellite-based analyses such as this gives us insight into where iron deposition may be limiting ocean biological activity,' says lead author David Erickson of Oak Ridge National Laboratory's Computer Science and Mathematics Division. 'With this information we will be able to infer how the ocean productivity/iron deposition relationship might shift in response to climate change.' Map Source: David Erickson, Oak Ridge National Laboratory's Computer Science and Mathematics Division

  16. Lift and Drag of Wings with Small Span

    NASA Technical Reports Server (NTRS)

    Weinig, F.

    1947-01-01

    The lift coefficient of!a wing of small span at first shows a linear increase for the increasing angle of attack, but to a lesser degree then was to be expected according to the theory of the lifting line; thereafter the lift coefficient increases more rapidly than linearity, as contrasted with the the theory of the lifting line. The induced drag coefficient for a given lift coefficient, on the other hand, is obviously much smaller than it would be according to the theory. A mall change in the theory of the lifting line will cover these deviations.

  17. Spatial and temporal distributions of Martian north polar cold spots before, during, and after the global dust storm of 2001

    USGS Publications Warehouse

    Cornwall, C.; Titus, T.N.

    2009-01-01

    In the 1970s, Mariner and Viking observed features in the Mars northern polar region that were a few hundred kilometers in diameter with 20 fj,m brightness temperatures as low as 130 K (considerably below C02 ice sublimation temperatures). Over the past decade, studies have shown that these areas (commonly called "cold spots") are usually due to emissivity effects of frost deposits and occasionally to active C02 snowstorms. Three Mars years of Mars Global Surveyor Thermal Emission Spectrometer data were used to observe autumn and wintertime cold spot activity within the polar regions. Many cold spots formed on or near scarps of the perennial cap, probably induced by adiabatic cooling due to orographic lifting. These topographically associated cold spots were often smaller than those that were not associated with topography. We determined that initial grain sizes within the cold spots were on the order of a few millimeters, assuming the snow was uncontaminated by dust or water ice. On average, the half-life of the cold spots was 5 Julian days. The Mars global dust storm in 2001 significantly affected cold spot activity in the north polar region. Though overall perennial cap cold spot activity seemed unaffected, the distribution of cold spots did change by a decrease in the number of topographically associated cold spots and an increase in those not associated with topography. We propose that the global dust storm affected the processes that form cold spots and discuss how the global dust storm may have affected these processes. ?? 2009 by the American Geophysical Union.

  18. Should precipitation influence dust emission in global dust models?

    NASA Astrophysics Data System (ADS)

    Okin, Gregory

    2016-04-01

    Soil moisture modulates the threshold shear stress required to initiate aeolian transport and dust emission. Most of the theoretical and laboratory work that has confirmed the impact of soil moisture has appropriately acknowledged that it is the soil moisture of a surface layer a few grain diameters thick that truly controls threshold shear velocity. Global and regional models of dust emission include the effect of soil moisture on transport threshold, but most ignore the fact that only the moisture of the very topmost "active layer" matters. The soil moisture in the active layer can differ greatly from that integrated through the top 2, 5, 10, or 100 cm (surface layers used by various global models) because the top 2 mm of heavy texture soils dries within ~1/2 day while sandy soils dry within less than 2 hours. Thus, in drylands where dust emission occurs, it is likely that this top layer is drier than the underlying soil in the days and weeks after rain. This paper explores, globally, the time between rain events in relation to the time for the active layer to dry and the timing of high wind events. This analysis is carried out using the same coarse reanalyses used in global dust models and is intended to inform the soil moisture controls in these models. The results of this analysis indicate that the timing between events is, in almost all dust-producing areas, significantly longer than the drying time of the active layer, even when considering soil texture differences. Further, the analysis shows that the probability of a high wind event during the period after a rain where the surface is wet is small. Therefore, in coarse global models, there is little reason to include rain-derived soil moisture in the modeling scheme.

  19. Urban dust in the Guanzhong basin of China, part II: A case study of urban dust pollution using the WRF-Dust model.

    PubMed

    Li, Nan; Long, Xin; Tie, Xuexi; Cao, Junji; Huang, Rujin; Zhang, Rong; Feng, Tian; Liu, Suixin; Li, Guohui

    2016-01-15

    We developed a regional dust dynamical model (WRF-Dust) to simulate surface dust concentrations in the Guanzhong (GZ) basin of China during two typical dust cases (19th Aug. and 26th Nov., 2013), and compared model results with the surface measurements at 17 urban and rural sites. The important improvement of the model is to employ multiple high-resolution (0.5-500 m) remote sensing data to construct dust sources. The new data include the geographic information of constructions, croplands, and barrens over the GZ basin in summer and winter of 2013. For the first time, detailed construction dust emissions have been introduced in a regional dust model in large cities of China. Our results show that by including the detailed dust sources, model performance at simulating dust pollutions in the GZ basin is significantly improved. For example, the simulated dust concentration average for the 17 sites increases from 28 μg m(-3) to 59 μg m(-3), closing to the measured concentration of 66 μg m(-3). In addition, the correlation coefficient (r) between the calculated and measured dust concentrations is also improved from 0.17 to 0.57, suggesting that our model better presents the spatial variation. Further analysis shows that urban construction activities are the crucial source in controlling urban dust pollutions. It should be considered by policy makers for mitigating particulate air pollution in many Chinese cities.

  20. Dust and Planetary Rings

    NASA Astrophysics Data System (ADS)

    Siddiqui, Muddassir

    ABSTRACT Space is not empty it has comic radiations (CMBR), dust etc. Cosmic dust is that type of dust which is composed of particles in space which vary from few molecules to 0.1micro metres in size. This type of dust is made up of heavier atoms born in the heart of stars and supernova. Mainly it contains dust grains and when these dust grains starts compacting then it turns to dense clouds, planetary ring dust and circumstellar dust. Dust grains are mainly silicate particles. Dust plays a major role in our solar system, for example in zodiacal light, Saturn's B ring spokes, planetary rings at Jovian planets and comets. Observations and measurements of cosmic dust in different regions of universe provide an important insight into the Universe's recycling processes. Astronomers consider dust in its most recycled state. Cosmic dust have radiative properties by which they can be detected. Cosmic dusts are classified as intergalactic dusts, interstellar dusts and planetary rings. A planetary ring is a ring of cosmic dust and other small particles orbiting around a planet in flat disc shape. All of the Jovian planets in our solar system have rings. But the most notable one is the Saturn's ring which is the brightest one. In March 2008 a report suggested that the Saturn's moon Rhea may have its own tenuous ring system. The ring swirling around Saturn consists of chunks of ice and dust. Most rings were thought to be unstable and to dissipate over course of tens or hundreds of millions of years but it now appears that Saturn's rings might be older than that. The dust particles in the ring collide with each other and are subjected to forces other than gravity of its own planet. Such collisions and extra forces tend to spread out the rings. Pluto is not known to have any ring system but some Astronomers believe that New Horizons probe might find a ring system when it visits in 2015.It is also predicted that Phobos, a moon of Mars will break up and form into a planetary ring

  1. Saltation Impact as a Means for Raising Dust on Mars

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald

    2002-01-01

    Experiments were conducted under atmospheric pressures appropriate for Earth and Mars to determine the efficiency of sand in saltation as a means for raising dust into the atmosphere under wind speeds which would otherwise be too low for dust entrainment. Experiments involving intimate mixtures of sand and dust (1:1 ratio by mass) showed that after an initial flurry of activity of a few seconds duration, the bed stabilized with little movement of either sand or dust. In contrast, sands set into saltation upwind fro= dust beds were efficient in injecting the dust into suspension, with low-pressure Martian conditions being some five times more efficient than terrestrial conditions. This result is attributed to the higher kinetic energies of the saltating grains on Mars, which is a consequence of the higher velocities of the grains. These results suggest that sands saltating across dust beds on Mars are an effective means for setting dust into suspension.

  2. Lofting of dust by very large explosions

    SciTech Connect

    Mason, A.S.; Finnegan, D.L.; Hagan, R.C.; Raymond, R. Jr.; Cocks, G.G.; Zoller, W.H.; Peach, C.L.

    1987-08-01

    One of the goals of the Minor Scale test was to determine the quantity, form, and composition of dust lofted by a large detonation of a conventional high explosive at ground level. The explosive charge was 4427 tonnes of ammonium nitrate-fuel oil (ANFO), whose blast effect is approximately equal to that of an 8 kT nuclear device. The experimental techniques used to determine the amount of dust were (1) use of elements in soil as natural tracers, (2) inclusion of tracer elements in the ANFO charge and the immediate surroundings, (3) airborne collection of the lofted dust on filter media, and (4) analysis of the samples for both tracers and dust. The tracer content of the sample can then relate the dust collected to the total amount lofted and to the location of its origin within the experimental setup. Indium, in the oxide form, was placed within the explosive charge, and tantalum as very fine dust, was placed near the soil surface immediately adjacent to the charge container. The amounts of the tracers and of dust collected by each filter were measured by instrumental neutron activation analysis. A research aircraft equipped with well-characterized high-volume filter samplers was flown through the dust cloud at 10 levels between the top at 4.6 km and the bottom at 1.7 km above ground level. The cloud dust density was distinctly biomodal; its maxima were at 4.1 and 2.9 km. The majority of the indium was associated with the dust in the upper part of the cloud, and the majority of the tantalum was in the lower part. The estimate of the total dust lofted by use of the naturally occurring tracers was 3.0 x 10/sup 9/ g. Samples are being studied by scanning electron microscopy to determine their particle size and composition distributions as functions of location within the cloud.

  3. Integration of multi-source measurements to monitor sand-dust storms over North China: A case study

    NASA Astrophysics Data System (ADS)

    Guo, Jianping; Niu, Tao; Wang, Fu; Deng, Minjun; Wang, Yaqiang

    2013-08-01

    The aerosol optical depth (AOD) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Satellite Aqua, along with the altitude-resolved aerosol subtypes product from the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP), as well as surface PM10 measurements, were utilized to investigate the dust activities common in springtime of northern China. Specifically, a dust storm episode that occurred over the North China Plain (NCP) during 17-21 March 2010 was identified. The PM10 concentration at Beijing (39.8°N, 116.47°E) reached the peak value of 283 µg m-3 on 20 March 2010 from the background value of 15 µg m-3 measured on 17 March 2010, then dropped to 176 µg m-3 on 21 March 2010. Analysis of the CALIOP aerosol subtypes product showed that numerous large dust plumes floated over northern China, downwind of main desert source regions, and were lifted to altitudes as high as 3.5 km during this time period. The MODIS AOD data provided spatial distributions of dust load, broadly consistent with ground-level PM10, especially in cloud free areas. However, inconsistency between the MODIS AOD and surface PM10 measurements under cloudy conditions did exist, further highlighting the unique capability of the CALIOP lidar. CALIOP can penetrate the cloud layer to give unambiguous and altitude-resolved dust measurements, albeit a relatively long revisit period (16 days) and narrower swath (90 m). A back trajectory simulation using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model was performed, and it was found that the sand-dust storm originated from the Gobi Desert on 18 March 2010 travelled approximately 1200-1500 km day-1 eastward and passed over the NCP on 19 March 2010, in good agreement with previous findings. In addition, the multi-sensor measurements integrated with the HYSPLIT model output formed a three-dimensional view of the transport pathway for this dust episode, indicating that this episode was largely

  4. The Monoplane as a Lifting Vortex Surface

    NASA Technical Reports Server (NTRS)

    Blenk, Hermann

    1947-01-01

    In Prandtl's airfoil theory the monoplane was replaced by a single lifting vortex line and yielded fairly practical results. However, the theory remained restricted to the straight wing. Yawed wings and those curved in flight direction could not be computed with this first approximation; for these the chordwise lift distribution must be taken into consideration. For the two-dimensional problem the transition from the lifting line to the lifting surface has been explained by Birnbaum. In the present report the transition to the three-dimensional problem is undertaken. The first fundamental problem involves the prediction of flow, profile, and drag for prescribed circulation distribution on the straight rectangular wing, the yawed wing for lateral boundaries parallel to the direction of flight, the swept-back wing, and the rectangular wing in slipping, with the necessary series developments for carrying through the calculations, the practical range of convergence of which does not comprise the wing tips or the break point of the swept-back wing. The second problem concerns the calculation of the circulation distribution with given profile for a slipping rectangular monoplane with flat profile and aspect ratio 6, and a rectangular wing with cambered profile and variable aspect ratio-the latter serving as check of the so-called conversion formulas of the airfoil theory.

  5. Measuring Lift with the Wright Airfoils

    ERIC Educational Resources Information Center

    Heavers, Richard M.; Soleymanloo, Arianne

    2011-01-01

    In this laboratory or demonstration exercise, we mount a small airfoil with its long axis vertical at one end of a nearly frictionless rotating platform. Air from a leaf blower produces a sidewise lift force L on the airfoil and a drag force D in the direction of the air flow (Fig. 1). The rotating platform is kept in equilibrium by adding weights…

  6. 29 CFR 1926.453 - Aerial lifts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ground: (i) Extensible boom platforms; (ii) Aerial ladders; (iii) Articulating boom platforms; (iv... articulating boom platforms. (i) Lift controls shall be tested each day prior to use to determine that such... when outriggers are used, they shall be positioned on pads or a solid surface. Wheel chocks shall...

  7. 29 CFR 1926.453 - Aerial lifts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ground: (i) Extensible boom platforms; (ii) Aerial ladders; (iii) Articulating boom platforms; (iv... articulating boom platforms. (i) Lift controls shall be tested each day prior to use to determine that such... when outriggers are used, they shall be positioned on pads or a solid surface. Wheel chocks shall...

  8. Coke dust enhances coke plant wastewater treatment.

    PubMed

    Burmistrz, Piotr; Rozwadowski, Andrzej; Burmistrz, Michał; Karcz, Aleksander

    2014-12-01

    Coke plant wastewater contain many toxic pollutants. Despite physico-chemical and biological treatment this specific type of wastewater has a significant impact on environment and human health. This article presents results of research on industrial adsorptive coke plant wastewater treatment. As a sorbent the coke dust, dozen times less expensive than pulverized activated carbon, was used. Treatment was conducted in three scenarios: adsorptive after full treatment with coke dust at 15 g L(-1), biological treatment enhanced with coke dust at 0.3-0.5 g L(-1) and addition of coke dust at 0.3 g L(-1) prior to the biological treatment. The enhanced biological treatment proved the most effective. It allowed additional removal of 147-178 mg COD kg(-1) of coke dust.

  9. Rocket dust storms and detached layers in the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Spiga, A.; Faure, J.; Madeleine, J.; Maattanen, A. E.; Forget, F.

    2012-12-01

    Airborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modeling with radiatively-active transported dust to predict the evolution of a local dust storm monitored by OMEGA onboard Mars Express. We show that the evolution of this dust storm is governed by deep convective motions. The supply of convective energy is provided by the absorption of incoming sunlight by dust particles, in lieu of latent heating in moist convection on Earth. We propose to use the terminology "rocket dust storm", or conio-cumulonimbus, to describe those storms in which rapid and efficient vertical transport takes place, injecting dust particles at high altitudes in the Martian troposphere (30 to 50 km). Combined to horizontal transport by large-scale winds, rocket dust storms form detached layers of dust reminiscent of those observed with instruments onboard Mars Global Surveyor and Mars Reconnaissance Orbiter. Detached layers are stable over several days owing to nighttime sedimentation being unable to counteract daytime convective transport, and to the resupply of convective energy at sunrise. The peak activity of rocket dust storms is expected in low-latitude regions at clear season, which accounts for the high-altitude tropical dust maximum unveiled by Mars Climate Sounder. Our findings on dust-driven deep convection have strong implications for the Martian dust cycle, thermal structure, atmospheric dynamics, cloud microphysics, chemistry, and robotic and human exploration.ensity-scaled dust optical depth at local times 1400 1600 and 1800 (lat 2.5°S, Ls 135°) hortwave heating rate at local time 1500 and latitude 2.5°S.

  10. View of lifting girder and tower support superstructure on Tensaw ...

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

    View of lifting girder and tower support superstructure on Tensaw River Bridge truss No. 2, looking northwest. Showing rope connectors and deflector sheaves. - Tensaw River Lift Bridge, Spanning Tensaw River at U.S. Highway 90, Mobile, Mobile County, AL

  11. 39. DETAIL AERIAL VIEW LOOKING AT 210' 9' LIFT SPAN ...

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

    39. DETAIL AERIAL VIEW LOOKING AT 210' 9' LIFT SPAN TOWER SHEAVES SHOWING 1 SET WITH AND 1 SET WITHOUT SHEAVE HOODS - Central Railroad of New Jersey, Newark Bay Lift Bridge, Spanning Newark Bay, Newark, Essex County, NJ

  12. Interior view of eastern lift span, with decking above, looking ...

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

    Interior view of eastern lift span, with decking above, looking back from center of span, toward lift mechanism area. - Arlington Memorial Bridge, Spanning Potomac River between Lincoln Memorial & Arlington National Cemetery, Washington, District of Columbia, DC

  13. 2. AERIAL VIEW OF ROLLING LIFT BRIDGE. DORCHESTER AVENUE IN ...

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

    2. AERIAL VIEW OF ROLLING LIFT BRIDGE. DORCHESTER AVENUE IN BACKGROUND. SOUTH STATION VISIBLE AT TOP LEFT. - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  14. View of central lift span truss web of Tensaw River ...

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

    View of central lift span truss web of Tensaw River Bridge, showing support girders for life house, looking east - Tensaw River Lift Bridge, Spanning Tensaw River at U.S. Highway 90, Mobile, Mobile County, AL

  15. GENERAL VIEW LOOKING WEST SHOWING LIFT BRIDGE. COUNTER WEIGHTS ARE ...

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

    GENERAL VIEW LOOKING WEST SHOWING LIFT BRIDGE. COUNTER WEIGHTS ARE LARGE SQUARES VISIBLE ABOVE BRIDGE - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  16. 3. GENERAL VIEW LOOKING WEST, SHOWING LIFT BRIDGE. COUNTER WEIGHTS ...

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

    3. GENERAL VIEW LOOKING WEST, SHOWING LIFT BRIDGE. COUNTER WEIGHTS ARE LARGE SQUARES VISIBLE ABOVE BRIDGE. - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  17. 6. DETAIL OF VERTICAL LIFT SPAN AND FIXED SPAN IMMEDIATELY ...

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

    6. DETAIL OF VERTICAL LIFT SPAN AND FIXED SPAN IMMEDIATELY NORTH OF VERTICAL LIFT SPAN, LOOKING SOUTHEAST. - Shippingsport Bridge, Spanning Illinois River at State Route 51, La Salle, La Salle County, IL

  18. 6. DETAIL VIEW OF 210' 9' LIFT SPAN TOWER SHEAVES ...

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

    6. DETAIL VIEW OF 210' 9' LIFT SPAN TOWER SHEAVES AND BEARINGS WITH HOUSING AND SHEAVE HOODS REMOVED - Central Railroad of New Jersey, Newark Bay Lift Bridge, Spanning Newark Bay, Newark, Essex County, NJ

  19. 2. DETAIL OF CONTROL GATE ADJACENT TO LIFT LOCK NO. ...

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

    2. DETAIL OF CONTROL GATE ADJACENT TO LIFT LOCK NO. 7; THIS CONTROL GATE IS A 1980s RECONSTRUCTION. - Illinois & Michigan Canal, Lift Lock No. 7 & Control Gate, East side of DuPage River, Channahon, Will County, IL

  20. 1. VIEW OF LIFT STATION (#1774), AND SHED (#1775) BEYOND ...

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

    1. VIEW OF LIFT STATION (#1774), AND SHED (#1775) BEYOND AT LEFT, LOOKING SOUTHWEST - Presidio Water Treatment Plant, Lift Station, East of Lobos Creek at Baker Beach, San Francisco, San Francisco County, CA