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Sample records for dynamics boom splash

  1. Dynamic Analysis of The Intelligent Sprayer Boom

    DEFF Research Database (Denmark)

    Wiggers, Sine Leergaard; Maagaard, Jørgen; Terp, Christian Istjord

    As part of the 3 year project “The intelligent Sprayer Boom”, financed by The Danish National Advanced Technology Foundation, the dynamics of the sprayer boom is to be analysed. In order to minimize the amount of herbicides used to kill the weeds in agriculture a new sprayer boom is being developed...... called “The intelligent sprayer boom”. For the sprayer boom the primary challenge is to hit the weeds with precision from a movable platform. Since the sprayer boom is mounted on a tractor the system will react to bumps in the field. The intelligent sprayer boom has an integrated camera technology...... system to work properly. At the University of Southern Denmark (SDU) a patent for an active damping system of the sprayer boom has been obtained. The subject of this paper is analysis of the dynamics of the Sprayer boom. The analysis is based on a Multibody Dynamics model of the sprayer boom and is made...

  2. Origin and dynamics of vortex rings in drop splashing.

    Science.gov (United States)

    Lee, Ji San; Park, Su Ji; Lee, Jun Ho; Weon, Byung Mook; Fezzaa, Kamel; Je, Jung Ho

    2015-09-04

    A vortex is a flow phenomenon that is very commonly observed in nature. More than a century, a vortex ring that forms during drop splashing has caught the attention of many scientists due to its importance in understanding fluid mixing and mass transport processes. However, the origin of the vortices and their dynamics remain unclear, mostly due to the lack of appropriate visualization methods. Here, with ultrafast X-ray phase-contrast imaging, we show that the formation of vortex rings originates from the energy transfer by capillary waves generated at the moment of the drop impact. Interestingly, we find a row of vortex rings along the drop wall, as demonstrated by a phase diagram established here, with different power-law dependencies of the angular velocities on the Reynolds number. These results provide important insight that allows understanding and modelling any type of vortex rings in nature, beyond just vortex rings during drop splashing.

  3. Splash Dynamics of Watercolors on Dry, Wet, and Cooled Surfaces

    Science.gov (United States)

    Baron, David; Vaidya, Ashwin; Su, Haiyan

    2015-11-01

    In his classic study in 1908, A.M. Worthington gave a thorough account of splashes and their formation through visualization experiments. In more recent times, there has been renewed interest in this subject, and much of the underlying physics behind Worthington's experiments has now been clarified. One specific set of such recent studies, which motivates this paper, concerns the fluid dynamics behind Jackson Pollock's drip paintings. The physical processes and the mathematical structures hidden in his works have received serious attention and made the scientific pursuit of art a compelling area of exploration. Our work explores the interaction of watercolors with watercolor paper. Specifically, we conduct experiments to analyze the settling patterns of droplets of watercolor paint on wet and frozen paper. Variations in paint viscosity, paper roughness, paper temperature, and the height of a released droplet are examined from time of impact, through its transient stages, until its final, dry state. Observable phenomena such as paint splashing, spreading, fingering, branching, rheological deposition, and fractal patterns are studied in detail and classified in terms of the control parameters.

  4. Dynamic modeling of oil boom failure using computational fluid dynamics

    International Nuclear Information System (INIS)

    Goodman, R. H.; Brown, H. M.; An, C. F.; Rowe, R. D.

    1997-01-01

    Oil retention boom failure mechanisms have been identified and studied using computational fluid dynamics (CFD), a powerful modeling tool combining fluid dynamics and mathematics with high speed computer technology. This study utilized a commercially available CFD package, 'Fluent', to simulate the oil-water flow around a barrier. 'Drainage failure', 'droplet entrainment' and 'critical accumulation' were modeled using this software. Flow characteristics were found to be different for different failure mechanisms. In the drainage failure process, the oil slick was compressed against the barrier until the slick was deep enough for the oil to leak under the barrier. During boom failure due to droplet entrainment, the oil-water interface of the oil slick was wavy and unstable. During boom failure due to critical accumulation, the oil remained a single mass and moved under the barrier readily. The most significant observation, however, was that flow patterns around barriers are modified by the presence of oil. Therefore, towing and wave-conformity tests of booms will not be meaningful unless such tests are conducted with oil present. 15 refs., 11 figs

  5. The shape and dynamics of the generation of the splash forms in single-phase systems after drop hitting

    Science.gov (United States)

    Sochan, Agata; Beczek, Michał; Mazur, Rafał; RyŻak, Magdalena; Bieganowski, Andrzej

    2018-02-01

    The splash phenomenon is being increasingly explored with the use of modern measurement tools, including the high-speed cameras. Recording images at a rate of several thousand frames per second facilitates parameterization and description of the dynamics of splash phases. This paper describes the impact of a single drop of a liquid falling on the surface of the same liquid. Three single-phase liquid systems, i.e., water, petrol, and diesel fuel, were examined. The falling drops were characterized by different kinetic energy values depending on the height of the fall, which ranged from 0.1 to 7.0 m. Four forms, i.e., waves, crowns, semi-closed domes, and domes, were distinguished depending on the drop energy. The analysis of the recorded images facilitated determination of the static and dynamic parameters of each form, e.g., the maximum height of each splash form, the width of the splash form at its maximum height, and the rate of growth of the splash form. We, Re, Fr, and K numbers were determined for all analyzed liquid systems. On the basis of the obtained values of dimensionless numbers, the areas of occurrence of characteristic splash forms were separated.

  6. Dynamic simulation of a planar flexible boom for tokamak in-vessel operations

    International Nuclear Information System (INIS)

    Ambrosino, G.; Celentano, G.; Garofalo, F.; Maisonnier, D.

    1991-01-01

    In this paper we present a dynamic model for the analysis of the vibrations of a planar articulated flexible boom to be used for tokamak in-vessel maintenance operations. The peculiarity of the mechanical structure of the boom enables us to consider separately the oscillations in the horizontal and vertical planes so that two separate models can be constructed for describing these phenomena. The results of simulations based on booms like that proposed for NET in-vessel operations are presented. (orig.)

  7. Research on rigid–flexible coupling dynamic characteristics of boom system in concrete pump truck

    Directory of Open Access Journals (Sweden)

    Hongbin Tang

    2015-03-01

    Full Text Available Concrete pump truck plays an important role in infrastructure construction and national economic development. In recent years, its boom system becomes longer, and its dynamic and control become more complicated. In order to study the dynamic characteristics of boom system, three dynamic models such as multi-rigid-body model, rigid–flexible coupling model, and rigid–flexible coupling model with equivalent hydraulic cylinder were built in this work. Simulation analysis and experimental analysis were done, and they show that we should not only consider the large-range motion but also consider the small flexible deformation to study the dynamic characteristics of boom system precisely. It provides the theoretical basis to vibration control, trajectory prediction, and life assessment for boom system and such structures.

  8. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Dynamics of splashing of molten metals during irradiation with single CO2 laser pulses

    Science.gov (United States)

    Arutyunyan, R. V.; Baranov, V. Yu; Bol'shov, Leonid A.; Dolgov, V. A.; Malyuta, D. D.; Mezhevov, V. S.; Semak, V. V.

    1988-03-01

    An experimental investigation was made of the dynamics of the loss of the melt as a result of interaction with single-mode CO2 laser radiation pulses of 5-35 μs duration. The dynamics of splashing of the melt during irradiation with short pulses characterized by a Gaussian intensity distribution differed from that predicted by models in which the distribution of the vapor pressure was assumed to be radially homogeneous.

  9. Method of Obtaining High Resolution Intrinsic Wire Boom Damping Parameters for Multi-Body Dynamics Simulations

    Science.gov (United States)

    Yew, Alvin G.; Chai, Dean J.; Olney, David J.

    2010-01-01

    The goal of NASA's Magnetospheric MultiScale (MMS) mission is to understand magnetic reconnection with sensor measurements from four spinning satellites flown in a tight tetrahedron formation. Four of the six electric field sensors on each satellite are located at the end of 60- meter wire booms to increase measurement sensitivity in the spin plane and to minimize motion coupling from perturbations on the main body. A propulsion burn however, might induce boom oscillations that could impact science measurements if oscillations do not damp to values on the order of 0.1 degree in a timely fashion. Large damping time constants could also adversely affect flight dynamics and attitude control performance. In this paper, we will discuss the implementation of a high resolution method for calculating the boom's intrinsic damping, which was used in multi-body dynamics simulations. In summary, experimental data was obtained with a scaled-down boom, which was suspended as a pendulum in vacuum. Optical techniques were designed to accurately measure the natural decay of angular position and subsequently, data processing algorithms resulted in excellent spatial and temporal resolutions. This method was repeated in a parametric study for various lengths, root tensions and vacuum levels. For all data sets, regression models for damping were applied, including: nonlinear viscous, frequency-independent hysteretic, coulomb and some combination of them. Our data analysis and dynamics models have shown that the intrinsic damping for the baseline boom is insufficient, thereby forcing project management to explore mitigation strategies.

  10. Bouncing, splashing and disintegrating nanodrops

    Science.gov (United States)

    Koplik, Joel; Zhang, Rui

    2012-11-01

    The impact of nanometer-sized drops on solid surfaces is studied by molecular dynamics simulations. The surfaces are atomically smooth, dry and non-wetting, and both volatile and non-volatile liquids are considered. At low impact velocities drops distort on contact but bounce off the surface and relax back to a spherical shape. At higher velocities drops form a prompt splash on impact and subsequently disintegrate, while at still higher velocities drops disintegrate immediately on impact. In contrast to macroscopic drops, the presence or absence of vapor plays no role at all in nanodrop splashing.

  11. The making of a splash

    KAUST Repository

    Thoroddsen, Sigurdur T.

    2011-12-20

    The splash resulting from the impact of a drop onto a pool is a particularly beautiful manifestation of a canonical problem, where a mass of fluid breaks up into smaller pieces. Despite over a century of experimental study, the splashing mechanics have eluded full description, the details often being obscured by the very rapid motions and small length scales involved. Zhang et al. (J. Fluid Mech., vol. 690, 2012, pp. 515) introduce a powerful new tool to the experimental arsenal, when they apply X-ray imaging to study the fine ejecta sheets which emerge during the earliest contact of the drop. Their images reveal hidden details and complex underlying dynamics, which will directly affect the size and velocity of the splashing droplets. © 2011 Cambridge University Press.

  12. SPLASH'13 workshops summary

    DEFF Research Database (Denmark)

    Balzer, S.; Schultz, U. P.

    2013-01-01

    Following its long-standing tradition, SPLASH 2013 will host 19 high-quality workshops, allowing their participants to meet and discuss research questions with peers, to mature new and exciting ideas, and to build up communities and start new collaborations. SPLASH workshops complement the main t...

  13. Thermal shock induced dynamics of a spacecraft with a flexible deploying boom

    Science.gov (United States)

    Shen, Zhenxing; Li, Huijian; Liu, Xiaoning; Hu, Gengkai

    2017-12-01

    The dynamics in the process of deployment of a flexible extendible boom as a deployable structure on the spacecraft is studied. For determining the thermally induced vibrations of the boom subjected to an incident solar heat flux, an axially moving thermal-dynamic beam element based on the absolute nodal coordinate formulation which is able to precisely describe the large displacement, rotation and deformation of flexible body is presented. For the elastic forces formulation of variable-length beam element, the enhanced continuum mechanics approach is adopted, which can eliminate the Poisson locking effect, and take into account the tension-bending-torsion coupling deformations. The main body of the spacecraft, modeled as a rigid body, is described using the natural coordinates method. In the derived nonlinear thermal-dynamic equations of rigid-flexible multibody system, the mass matrix is time-variant, and a pseudo damping matrix which is without actual energy dissipation, and a heat conduction matrix which is relative to the moving speed and the number of beam element are arisen. Numerical results give the dynamic and thermal responses of the nonrotating and spinning spacecraft, respectively, and show that thermal shock has a significant influence on the dynamics of spacecraft.

  14. Standardization of splash device

    Science.gov (United States)

    Fernández Raga, María; Peters, Piet

    2017-04-01

    The erosion is a complex process that has been studied extensively by numerous researchers, requiring a prolongued time effort and a large economic investment. To be effective, the measurements of erosion should be precise, controlled and replicable, and to assure efectiveness, measurement devices of erosion should be properly designed, constructed, well calibrated and also they should be operated by a trained person (Stroosnijder, 2005). Because researchers try to improve old devices, the equipment is constantly being redesigned, making the measurements not comparable and furthermore, producing a lack of available standarized device. The lack of standardization of erosion equipment is more obvious in the case of the local splash erosion, where the nature of the process makes very difficult to isolate its effects. In this article we compare the results obtained from five of the most common splash erosion devices (selected from more than 16 different currently types), under the same rain conditions, with the objective of facilitate the standardization of the method that will be more easy to build, minimizing the error. A set of six splash devices were setted in well known positions under simulated rain, to measured the differences, among devices and the accuracy of the data recovered after 10 minutes of rainfall simulation under different intensities (from 60 to 130 mm/h). The rainfall simulator of Wageningen was used, using sand as splash erosion source. Differences in the infiltration were also measured, and a calibration of sizes and speeds of the raindrops was done using the photography method (Hamidreza-Sadeghi et al., 2013). The splash devices selected for this study were unbounded splash devices (like the funnel, the cup (Fernandez-Raga et al., 2010) and the splash flume (Jomaa et al., 2010)), and bounded devices that allow the calculation of splash rate, (like the new cup (Scholten et al., 2011) and the Morgan tray). The behaviour of different splash devices

  15. Splash erosion. A bibliometric Review

    Science.gov (United States)

    Fernández Raga, M. B.

    2012-04-01

    Ellison (1944) developed the splash board as a system for measuring splash erosion that was both cheap and reliable. Bollinne (1975), Morgan (1978, 1981). Mutchler (1967) described another different type of splash detectors according to whether they were passive or could register data. In the study mentioned above these authors included bottles, funnels, glasses, photography, markers. After that several devices has been made up like the splash sampler (Leguedois et al., 2005), soil tray (Van Dijk et al., 2002), splash funnel (Terry, 1989) and several rain cups (Fernandez-Raga et al., 2010; Molina and Llinares, 1996; Torri et al., 1987). Splash erosion research has materialized in the form of a number of papers published in international journals. The database of bibliographic references employed has been one of the most prestigious ones: theWeb of Science (ISI). The search was carried out on January 27th 2012. Among the 3x10^8 scholarly documents included in the Science Citation Index Expanded (SCI-EXPANDED) 1899 to present , the searching engine located 439 containing the word "splash erosion*", where the asterisk acts as a wildcard for any letter or group of letters. Of these, 383 were classified as articles, 87 as proceeding papers, 5 as editorial material, 2 as notes and 1 as correction. These documents have been published in 163 different journals, although four are particularly recurrent: Earth surface processes and Landforms, Catena, Soil Science Society of America Journal and Hydrological processes, with 41, 35, 35 and 26 published documents respectively. A geographic analysis of these articles has been carried out in an attempt to determine in what parts of the world research projects were making use of splash erosion. The results are that anglo-saxon countries, as USA, England and Australia dominate, particularly USA, with 130 articles. China and Japan are large communities of researches too, and some Central European countries as Belgium, France Germany

  16. Prototype Development and Dynamic Characterization of Deployable CubeSat Booms

    Science.gov (United States)

    2010-03-01

    from a CubeSat and provide a proper footing for those individuals who follow. 3.8 SLiMSat Design and Downselect Notionally, the design of SLiMSat...all the nodes on one end of the beam. This constraint is somewhat unrealistic as the actual fixation of the physical boom utilizes friction fit...as in Figure 37. The resultant structure was then anchored to the top of the cinder block lab wall with eight large lag screws providing a rigid

  17. Boom or bust? A comparative analysis of transient population dynamics in plants

    DEFF Research Database (Denmark)

    Stott, Iain; Franco, Miguel; Carslake, David

    2010-01-01

    a population must become before reaching its maximum possible transient amplification following a disturbance) and the extension of this and other transient indices to simultaneously describe both amplified and attenuated transient dynamics. We apply the Kreiss bound and other transient indices to a data base......Population dynamics often defy predictions based on empirical models, and explanations for noisy dynamics have ranged from deterministic chaos to environmental stochasticity. Transient (short-term) dynamics following disturbance or perturbation have recently gained empirical attention from...... succession have the highest potential for transient amplification and attenuation, whereas species with intermediate life history complexity have the lowest potential. We find ecological relationships between transients and asymptotic dynamics: faster-growing populations tend to have greater potential...

  18. Boom-bust dynamics in biological invasions: towards an improved application of the concept

    Czech Academy of Sciences Publication Activity Database

    Strayer, D.L.; D'Antonio, C. M.; Essl, F.; Fowler, M. S.; Geist, J.; Hilt, S.; Jaric, I.; Jöhnk, K.; Jones, C. G.; Lambin, X.; Latzka, A. W.; Pergl, Jan; Pyšek, Petr; Robertson, P.; von Schmalensee, M.; Stefansson, R. A.; Wright, J.; Jeschke, J.M.

    2017-01-01

    Roč. 20, č. 10 (2017), s. 1337-1350 ISSN 1461-023X R&D Projects: GA ČR GA17-19025S; GA ČR GB14-36079G Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : invasions * population dynamics * alien species Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 9.449, year: 2016

  19. Drop impact splashing and air entrapment

    KAUST Repository

    Thoraval, Marie-Jean

    2013-03-01

    Drop impact is a canonical problem in fluid mechanics, with numerous applications in industrial as well as natural phenomena. The extremely simple initial configuration of the experiment can produce a very large variety of fast and complex dynamics. Scientific progress was made in parallel with major improvements in imaging and computational technologies. Most recently, high-speed imaging video cameras have opened the exploration of new phenomena occurring at the micro-second scale, and parallel computing allowed realistic direct numerical simulations of drop impacts. We combine these tools to bring a new understanding of two fundamental aspects of drop impacts: splashing and air entrapment. The early dynamics of a drop impacting on a liquid pool at high velocity produces an ejecta sheet, emerging horizontally in the neck between the drop and the pool. We show how the interaction of this thin liquid sheet with the air, the drop or the pool, can produce micro-droplets and bubble rings. Then we detail how the breakup of the air film stretched between the drop and the pool for lower impact velocities can produce a myriad of micro-bubbles.

  20. Drop splashing is independent of substrate wetting

    Science.gov (United States)

    Latka, Andrzej; Boelens, Arnout M. P.; Nagel, Sidney R.; de Pablo, Juan J.

    2018-02-01

    A liquid drop impacting a dry solid surface with sufficient kinetic energy will splash, breaking apart into numerous secondary droplets. This phenomenon shows many similarities to forced wetting, including the entrainment of air at the contact line. Because of these similarities and the fact that forced wetting has been shown to depend on the wetting properties of the surface, existing theories predict splashing to depend on wetting properties as well. However, using high-speed interference imaging, we observe that at high capillary numbers wetting properties have no effect on splashing for various liquid-surface combinations. Additionally, by fully resolving the Navier-Stokes equations at length and time scales inaccessible to experiments, we find that the shape and motion of the air-liquid interface at the contact line/edge of the droplet are independent of wettability. We use these findings to evaluate existing theories and to compare splashing with forced wetting.

  1. Impact splash chondrule formation during planetesimal recycling

    Science.gov (United States)

    Lichtenberg, Tim; Golabek, Gregor J.; Dullemond, Cornelis P.; Schönbächler, Maria; Gerya, Taras V.; Meyer, Michael R.

    2018-03-01

    Chondrules, mm-sized igneous-textured spherules, are the dominant bulk silicate constituent of chondritic meteorites and originate from highly energetic, local processes during the first million years after the birth of the Sun. So far, an astrophysically consistent chondrule formation scenario explaining major chemical, isotopic and textural features, in particular Fe,Ni metal abundances, bulk Fe/Mg ratios and intra-chondrite chemical and isotopic diversity, remains elusive. Here, we examine the prospect of forming chondrules from impact splashes among planetesimals heated by radioactive decay of short-lived radionuclides using thermomechanical models of their interior evolution. We show that intensely melted planetesimals with interior magma oceans became rapidly chemically equilibrated and physically differentiated. Therefore, collisional interactions among such bodies would have resulted in chondrule-like but basaltic spherules, which are not observed in the meteoritic record. This inconsistency with the expected dynamical interactions hints at an incomplete understanding of the planetary growth regime during the lifetime of the solar protoplanetary disk. To resolve this conundrum, we examine how the observed chemical and isotopic features of chondrules constrain the dynamical environment of accreting chondrite parent bodies by interpreting the meteoritic record as an impact-generated proxy of early solar system planetesimals that underwent repeated collision and reaccretion cycles. Using a coupled evolution-collision model we demonstrate that the vast majority of collisional debris feeding the asteroid main belt must be derived from planetesimals which were partially molten at maximum. Therefore, the precursors of chondrite parent bodies either formed primarily small, from sub-canonical aluminum-26 reservoirs, or collisional destruction mechanisms were efficient enough to shatter planetesimals before they reached the magma ocean phase. Finally, we outline the

  2. Boundary-layer effects in droplet splashing

    Science.gov (United States)

    Riboux, Guillaume; Gordillo, Jose Manuel

    2017-11-01

    A drop falling onto a solid substrate will disintegrate into smaller parts when its impact velocity exceeds the so called critical velocity for splashing. Under these circumstances, the very thin liquid sheet ejected tangentially to the solid after the drop touches the substrate, lifts off as a consequence of the aerodynamic forces exerted on it and finally breaks into smaller droplets, violently ejected radially outwards, provoking the splash. Here, the tangential deceleration experienced by the fluid entering the thin liquid sheet is investigated making use of boundary layer theory. The velocity component tangent to the solid, computed using potential flow theory provides the far field boundary condition as well as the pressure gradient for the boundary layer equations. The structure of the flow permits to find a self similar solution of the boundary layer equations. This solution is then used to calculate the boundary layer thickness at the root of the lamella as well as the shear stress at the wall. The splash model presented in, which is slightly modified to account for the results obtained from the boundary layer analysis, provides a very good agreement between the measurements and the predicted values of the critical velocity for the splash.

  3. X-Boom, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed X-Boom is an innovation on rollable boom design directly relevant to NASA SBIR topic H5.01, Deployable Structures. The X-boom is a rollable Carbon Fiber...

  4. Booming Sand Dunes

    Science.gov (United States)

    Vriend, Nathalie

    "Booming" sand dunes are able to produce low-frequency sound that resembles a pure note from a music instrument. The sound has a dominant audible frequency (70-105 Hz) and several higher harmonics and may be heard from far distances away. A natural or induced avalanche from a slip face of the booming dune triggers the emission that may last for several minutes. There are various references in travel literature to the phenomenon, but to date no scientific explanation covered all field observations. This thesis introduces a new physical model that describes the phenomenon of booming dunes. The waveguide model explains the selection of the booming frequency and the amplification of the sound in terms of constructive interference in a confined geometry. The frequency of the booming is a direct function of the dimensions and velocities in the waveguide. The higher harmonics are related to the higher modes of propagation in the waveguide. The experimental validation includes quantitative field research at the booming dunes of the Mojave Desert and Death Valley National Park. Microphone and geophone recordings of the acoustic and seismic emission show a variation of booming frequency in space and time. The analysis of the sensor data quantifies wave propagation characteristics such as speed, dispersion, and nonlinear effects and allows the distinction between the source mechanism of the booming and the booming itself. The migration of sand dunes results from a complicated interplay between dune building, wind regime, and precipitation. The morphological and morphodynamical characteristics of two field locations are analyzed with various geophysical techniques. Ground-penetrating radar images the subsurface structure of the dunes and reveal a natural, internal layering that is directly related to the history of dune migration. The seismic velocity increases abruptly with depth and gradually increases with downhill position due to compaction. Sand sampling shows local

  5. Boundary-layer effects in droplet splashing

    Science.gov (United States)

    Riboux, Guillaume; Gordillo, José Manuel

    2017-07-01

    A drop falling onto a solid substrate will disintegrate into smaller parts when its impact velocity V exceeds the so-called critical velocity for splashing, i.e., when V >V* . Under these circumstances, the very thin liquid sheet, which is ejected tangentially to the solid after the drop touches the substrate, lifts off as a consequence of the aerodynamic forces exerted on it. Subsequently, the growth of capillary instabilities breaks the toroidal rim bordering the ejecta into smaller droplets, violently ejected radially outward, provoking the splash [G. Riboux and J. M. Gordillo, Phys. Rev. Lett. 113, 024507 (2014)], 10.1103/PhysRevLett.113.024507. In this contribution, the effect of the growth of the boundary layer is included in the splash model presented in Phys. Rev. Lett. 113, 024507 (2014), 10.1103/PhysRevLett.113.024507, obtaining very good agreement between the measured and the predicted values of V* for wide ranges of liquid and gas material properties, atmospheric pressures, and substrate wettabilities. Our description also modifies the way at when the liquid sheet is first ejected, which can now be determined in a much more straightforward manner than that proposed in Phys. Rev. Lett. 113, 024507 (2014), 10.1103/PhysRevLett.113.024507.

  6. Splash of a liquid drop on a dry solid surface

    Science.gov (United States)

    Mishra, Shruti; Mandre, Shreyas; Rycroft, Chris; Brenner, Michael

    2015-11-01

    We study the early-time fluid mechanical phenomena of the splash of a liquid drop on a solid surface, focusing on the dynamics before contact through the intervening air layer. Previous theoretical work (e.g. Mani, Mandre and Brenner) on this problem neglected viscous effects in the liquid. However, a set of recent experiments show definitively that even at early times viscous effects in the liquid are important, and in particular have the ability to dramatically change the shape of the interface before contact. We describe a set of computations aimed to reproduce these experimental features. The simulations couple lubrication flow in the gas layer with nonsteady Stokes flow in the liquid, and surface tension at the liquid-air interface.

  7. Managing Credit Booms and Busts : A Pigouvian Taxation Approach

    NARCIS (Netherlands)

    Jeanne, O.; Korinek, A.

    2010-01-01

    We study a dynamic model in which the interaction between debt ac- cumulation and asset prices magni es credit booms and busts. We find that borrowers do not internalize these feedback e¤ects and therefore suf- fer from excessively large booms and busts in both credit flows and asset prices. We show

  8. ATLAS Splash event - 6 April 2018

    CERN Multimedia

    ATLAS Collaboration

    2018-01-01

    The image shows a visualization of experimental data coming from the 'beam splash' tests run in April 2018 as part of the restart process of the LHC accelerator, after the winter break for maintenance. The image shows the hits of part of the tracking detector (in red, at the center), the energy deposits in the electromagnetic calorimeter (in green), and those in the hadronic calorimeter (in yellow). The semi-transparent azure volumes are part of the hadronic calorimeter, while the grey outer structure is part of the muon spectrometer.

  9. Effects of Crop Canopies on Rain Splash Detachment

    Science.gov (United States)

    Ma, Bo; Yu, Xiaoling; Ma, Fan; Li, Zhanbin; Wu, Faqi

    2014-01-01

    Crops are one of the main factors affecting soil erosion in sloping fields. To determine the characteristics of splash erosion under crop canopies, corn, soybean, millet, and winter wheat were collected, and the relationship among splash erosion, rainfall intensity, and throughfall intensity under different crop canopies was analyzed through artificial rainfall experiments. The results showed that, the mean splash detachment rate on the ground surface was 390.12 g/m2·h, which was lower by 67.81% than that on bare land. The inhibiting effects of crops on splash erosion increased as the crops grew, and the ability of the four crops to inhibit splash erosion was in the order of winter wheat>corn>soybeans>millet. An increase in rainfall intensity could significantly enhance the occurrence of splash erosion, but the ability of crops to inhibit splash erosion was 13% greater in cases of higher rainfall intensity. The throughfall intensity under crop canopies was positively related to the splash detachment rate, and this relationship was more significant when the rainfall intensity was 40 mm/h. Splash erosion tended to occur intensively in the central row of croplands as the crop grew, and the non-uniformity of splash erosion was substantial, with splash erosion occurring mainly between the rows and in the region directly under the leaf margin. This study has provided a theoretical basis for describing the erosion mechanisms of cropland and for assisting soil erosion prediction as well as irrigation and fertilizer management in cultivated fields. PMID:24992386

  10. Influence of surface structure and chemistry on water droplet splashing.

    Science.gov (United States)

    Koch, Kerstin; Grichnik, Roland

    2016-08-06

    Water droplet splashing and aerosolization play a role in human hygiene and health systems as well as in crop culturing. Prevention or reduction of splashing can prevent transmission of diseases between animals and plants and keep technical systems such as pipe or bottling systems free of contamination. This study demonstrates to what extent the surface chemistry and structures influence the water droplet splashing behaviour. Smooth surfaces and structured replicas of Calathea zebrina (Sims) Lindl. leaves were produced. Modification of their wettability was done by coating with hydrophobizing and hydrophilizing agents. Their wetting was characterized by contact angle measurement and splashing behaviour was observed with a high-speed video camera. Hydrophobic and superhydrophilic surfaces generally showed fewer tendencies to splash than hydrophobic ones. Structuring amplified the underlying behaviour of the surface chemistries, increasing hydrophobic surfaces' tendency to splash and decreasing splash on hydrophilic surfaces by quickly transporting water off the impact point by capillary forces. The non-porous surface structures found in C. zebrina could easily be applied to technical products such as plastic foils or mats and coated with hydrophilizing agents to suppress splash in areas of increased hygiene requirements or wherever pooling of liquids is not desirable.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. © 2016 The Author(s).

  11. The effectiveness of detection of splashed particles using a system of three integrated high-speed cameras

    Science.gov (United States)

    Ryżak, Magdalena; Beczek, Michał; Mazur, Rafał; Sochan, Agata; Bieganowski, Andrzej

    2017-04-01

    The phenomenon of splash, which is one of the factors causing erosion of the soil surface, is the subject of research of various scientific teams. One of efficient methods of observation and analysis of this phenomenon are high-speed cameras to measure particles at 2000 frames per second or higher. Analysis of the phenomenon of splash with the use of high-speed cameras and specialized software can reveal, among other things, the number of broken particles, their speeds, trajectories, and the distances over which they were transferred. The paper presents an attempt at evaluation of the efficiency of detection of splashed particles with the use of a set of 3 cameras (Vision Research MIRO 310) and software Dantec Dynamics Studio, using a 3D module (Volumetric PTV). In order to assess the effectiveness of estimating the number of particles, the experiment was performed on glass beads with a diameter of 0.5 mm (corresponding to the sand fraction). Water droplets with a diameter of 4.2 mm fell on a sample from a height of 1.5 m. Two types of splashed particles were observed: particle having a low range (up to 18 mm) splashed at larger angles and particles of a high range (up to 118 mm) splashed at smaller angles. The detection efficiency the number of splashed particles estimated by the software was 45 - 65% for particles with a large range. The effectiveness of the detection of particles by the software has been calculated on the basis of comparison with the number of beads that fell on the adhesive surface around the sample. This work was partly financed from the National Science Centre, Poland; project no. 2014/14/E/ST10/00851.

  12. Modification of booming level for higher correlation with booming sensation; Booming level no koseidoka

    Energy Technology Data Exchange (ETDEWEB)

    Hatano, S.; Hashimoto, T. [Seikei University, Tokyo (Japan)

    1997-10-01

    In our previous study, we proposed a objective measure, i.e., Booming Level for quantifying booming sensation caused by car interior noise. In this paper, Booming Level was modified with its weighting function and within the process of calculation 1/3 octave band level was modified for the best match with subjective result. These modifications were conducted through a subjective experiment rating booming sensation with sounds having much lower frequency contents below 63Hz. With this modified Booming Level, we have obtained higher correlation for rating booming sensation with sounds having prominent low frequency components. 1 ref., 10 figs.

  13. Droplet Splashing by a Slingshot Mechanism

    KAUST Repository

    Thoroddsen, Sigurdur T.

    2011-01-18

    When a drop impacts onto a liquid pool, it ejects a thin horizontal sheet of liquid, which emerges from the neck region connecting the two liquid masses. The leading section of this ejecta bends down to meet the pool liquid. When the sheet touches the pool, at an “elbow,” it ruptures and sends off microdroplets by a slingshot mechanism, driven by surface tension. High-speed imaging of the splashing droplets suggests the liquid sheet is of submicron thickness, as thin as 300 nm. Experiments in partial vacuum show that air resistance plays the primary role in bending the sheet. We identify a parameter regime where this slingshot occurs and also present a simple model for the sheet evolution, capable of reproducing the overall shape.

  14. Micro-splashing by drop impacts

    KAUST Repository

    Thoroddsen, Sigurdur T.

    2012-07-18

    We use ultra-high-speed video imaging to observe directly the earliest onset of prompt splashing when a drop impacts onto a smooth solid surface. We capture the start of the ejecta sheet travelling along the solid substrate and show how it breaks up immediately upon emergence from the underneath the drop. The resulting micro-droplets are much smaller and faster than previously reported and may have gone unobserved owing to their very small size and rapid ejection velocities, which approach 100 m s-1, for typical impact conditions of large rain drops. We propose a phenomenological mechanism which predicts the velocity and size distribution of the resulting microdroplets. We also observe azimuthal undulations which may help promote the earliest breakup of the ejecta. This instability occurs in the cusp in the free surface where the drop surface meets the radially ejected liquid sheet. © 2012 Cambridge University Press.

  15. First beam splashes at the LHC

    CERN Multimedia

    CERN Bulletin

    2015-01-01

    After a two-year shutdown, the first beams of Run 2 circulated in the LHC last Sunday. On Tuesday, the LHC operators performed dedicated runs to allow some of the experiments to record their first signals coming from particles splashed out when the circulating beams hit the collimators. Powerful reconstruction software then transforms the electronic signals into colourful images.     “Splash” events are used by the experiments to test their numerous subdetectors and to synchronise them with the LHC clock. These events are recorded when the path of particles travelling in the LHC vacuum pipe is intentionally obstructed using collimators – one-metre-long graphite or tungsten jaws that are also used to catch particles that wander too far from the beam centre and to protect the accelerator against unavoidable regular and irregular beam losses. The particles sprayed out of the collision between the beam and the collimators are mostly muons. ATLAS and CMS&...

  16. Two mechanisms of droplet splashing on a solid substrate

    KAUST Repository

    Jian, Zhen

    2017-11-29

    We investigate droplet impact on a solid substrate in order to understand the influence of the gas in the splashing dynamics. We use numerical simulations where both the liquid and the gas phases are considered incompressible in order to focus on the gas inertial and viscous contributions. We first confirm that the dominant gas effect on the dynamics is due to its viscosity through the cushioning of the gas layer beneath the droplet. We then describe an additional inertial effect that is directly related to the gas density. The two different splashing mechanisms initially suggested theoretically are observed numerically, depending on whether a jet is created before or after the impacting droplet wets the substrate. Finally, we provide a phase diagram of the drop impact outputs as the gas viscosity and density vary, emphasizing the dominant effect of the gas viscosity with a small correction due to the gas density. Our results also suggest that gas inertia influences the splashing formation through a Kelvin–Helmholtz-like instability of the surface of the impacting droplet, in agreement with former theoretical works.

  17. Preventive medicine oversight of splash pads on military installations.

    Science.gov (United States)

    Hardcastle, Lisa Raysby; Perry, Matthew; Browne, Ashley

    2015-01-01

    Over the past several years, an increasing number of military installations have installed splash pads that provide fun, recreational water entertainment for Soldiers and their families. The addition of splash pads brings added responsibilities for medical treatment facility preventive medicine oversight and installation facilities maintenance to ensure a safe and healthy environment. Currently, there are no consistent standards or detailed guidance for military installations to follow when installing and maintaining splash pads. The central issues associated with splash pads on military installations are water quality and risk for waterborne illnesses, responsibility for safety and health oversight, and federal energy and water sustainability mandates. This article examines the importance of implementing a standard for design and oversight to ensure the health and safety of Soldiers and their families.

  18. Drop splashing: the role of surface wettability and liquid viscosity

    Science.gov (United States)

    Almohammadi, Hamed; Amirfazli, Alidad; -Team

    2017-11-01

    There are seemingly contradictory results in the literature about the role of surface wettability and drop viscosity for the splashing behavior of a drop impacting onto a surface. Motivated by such issues, we conducted a systematic experimental study where splashing behavior for a wide range of the liquid viscosity (1-100 cSt) and surface wettability (hydrophilic to hydrophobic) are examined. The experiments were performed for the liquids with both low and high surface tensions ( 20 and 72 mN/m). We found that the wettability affects the splashing threshold at high or low contact angle values. At the same drop velocity, an increase of the viscosity (up to 4 cSt) promotes the splashing; while, beyond such value, any increase in viscosity shows the opposite effect. It is also found that at a particular combination of liquid surface tension and viscosity (e.g. silicone oil, 10 cSt), an increase in the drop velocity changes the splashing to spreading. We relate such behaviors to the thickness, shape, and the velocity of the drop's lamella. Finally, to predict the splashing, we developed an empirical correlation which covers all of the previous reported data, hence clarifying the ostensible existing contradictions.

  19. Splash Safety During Dermatologic Procedures Among US Dermatology Residents.

    Science.gov (United States)

    Korta, Dorota Z; Chapman, Lance W; Lee, Patrick K; Linden, Kenneth G

    2017-07-01

    Dermatologists are at potential risk of acquiring infections from contamination of the mucous membranes by blood and body fluids. However, there are little data on splash safety during procedural dermatology. To determine dermatology resident perceptions about splash risk during dermatologic procedures and to quantify the rate of protective equipment use. An anonymous on-line survey was sent to 108 United States ACGME-approved dermatology residency programs assessing frequency of facial protection during dermatologic procedures, personal history of splash injury, and, if applicable, reasons for not always wearing facial protection. A total of 153 dermatology residents responded. Rates of facial protection varied by procedure, with the highest rates during surgery and the lowest during local anesthetic injection. Over 54% of respondents reported suffering facial splash while not wearing facial protection during a procedure. In contrast, 88.9% of respondents correctly answered that there is a small risk of acquiring infection from mucosal splash. Residency program recommendations for facial protection seem to vary by procedure. The authors' results demonstrate that although facial splash is a common injury, facial protection rates and protective recommendations vary significantly by procedure. These data support the recommendation for enhanced facial protection guidelines during procedural dermatology.

  20. State of the art of sonic boom modeling.

    Science.gov (United States)

    Plotkin, Kenneth J

    2002-01-01

    Based on fundamental theory developed through the 1950s and 1960s, sonic boom modeling has evolved into practical tools. Over the past decade, there have been requirements for design tools for an advanced supersonic transport, and for tools for environmental assessment of various military and aerospace activities. This has resulted in a number of advances in the understanding of the physics of sonic booms, including shock wave rise times, propagation through turbulence, and blending sonic boom theory with modern computational fluid dynamics (CFD) aerodynamic design methods. This article reviews the early fundamental theory, recent advances in theory, and the application of these advances to practical models.

  1. Numerical Study of Splash Detail Due to Grain Impact on Granular Bed

    Science.gov (United States)

    Tanabe, Takahiro; Niiya, Hirofumi; Awazu, Akinori; Nishimori, Hiraku

    2017-04-01

    Massive sediment transport phenomena, such as sand storm and drifting snow, pose a considerable threat to human life. Further, the formation of geomorphological patterns on sand-desert and snowfield surfaces as a result of sediment transport, such as dunes and ripples, is of considerable research interest. Because the major component of the grain entrainment into the air is caused by both the collision and ejection, it is necessary to focus on the collisions between wind-blown grains and surface of sand field along with the resultant ejection grains from the surfaces, which processes are, as a whole, called a splash process. However, because of complexity of jumping grains over the ground surface, detailed measurement is very hard. Therefore, to investigate the splash process, we simulate detailed process of splash caused by 1-grain impact onto a randomly packed granular bed using discrete element method. As a result, we obtained good correspondence between our numerical results and the findings of previous experiments for the movement of ejected grains. Furthermore, the distributions of the ejection angle and the vertical ejection speed for individual grains vary depending on the relative timing at which the grains are ejected after the initial impact. Obvious differences are observed between the distributions of grains ejected during the earlier and later splash periods: the form of the vertical ejection-speed distribution varies from a power-law form to a lognormal form with time, and this difference is related to the grain trajectory after ejection [1]. In addition, we focus on the bulk dynamics inside the granular bed to relate the ejected grains behavior to the force propagations from the first impact to the ejection of each grain. [1] T. Tanabe, T. Shimada, N. Ito, and, H. Nishimori, (submitted)

  2. Bust without boom.

    Science.gov (United States)

    Goldzieher, J W

    2000-01-01

    Just like injectables, oral contraceptives (OCs), including progestin-only ¿minipill¿ and ¿morning-after¿ pill regimens, have experienced a bust without a boom. Fear of political and religious backlash over emergency contraceptives containing estrogen and progestin prompted large companies not to market these regimens. Another major factor in the bust phase of OC use and acceptance has been a small coterie of English and American epidemiologists focused on the adverse effects of Ocs, including risks of thrombotic events, heart attacks, and strokes. The media played a crucial role in the bust phase of these OCs. In the UK, the alleged increase of cancer risk with pill use, which leaked before publication in London newspapers, resulted in 50,000 additional unintended pregnancies. Nevertheless, there is no doubt that boom-and-bust cycles will continue simply because many of the actors in this drama have too great a vested interest to desist. Groups involved in this field must recognize the hazards that come with the territory and be proactive, anticipatory, and well armed with facts--and get good with media access. Drug companies should think on a long-term basis the potential effects of leaving the field, as they have done, or shooting down competitive innovations.

  3. Using CFD Surface Solutions to Shape Sonic Boom Signatures Propagated from Off-Body Pressure

    Science.gov (United States)

    Ordaz, Irian; Li, Wu

    2013-01-01

    The conceptual design of a low-boom and low-drag supersonic aircraft remains a challenge despite significant progress in recent years. Inverse design using reversed equivalent area and adjoint methods have been demonstrated to be effective in shaping the ground signature propagated from computational fluid dynamics (CFD) off-body pressure distributions. However, there is still a need to reduce the computational cost in the early stages of design to obtain a baseline that is feasible for low-boom shaping, and in the search for a robust low-boom design over the entire sonic boom footprint. The proposed design method addresses the need to reduce the computational cost for robust low-boom design by using surface pressure distributions from CFD solutions to shape sonic boom ground signatures propagated from CFD off-body pressure.

  4. Seismic detection of sonic booms.

    Science.gov (United States)

    Cates, Joseph E; Sturtevant, Bradford

    2002-01-01

    The pressure signals from a sonic boom will produce a small, but detectable, ground motion. The extensive seismic network in southern California, consisting of over 200 sites covering over 50000 square kilometers, is used to map primary and secondary sonic boom carpets. Data from the network is used to analyze three supersonic overflights in the western United States. The results are compared to ray-tracing computations using a realistic model of the stratified atmospheric at the time of the measurements. The results show sonic boom ground exposure under the real atmosphere is much larger than previously expected or predicted by ray tracing alone. Finally, seismic observations are used to draw some inferences on the origin of a set of "mystery booms" recorded in 1992-1993 in southern California.

  5. Dispersal of seeds from splash-cup plants

    Science.gov (United States)

    Pepper, Rachel

    2017-11-01

    Splash cup plants disperse their seeds with the help of raindrops. The seeds sit in a small (mm-scale) conical cup and are ejected upon drop impact. The seeds are ejected at velocities up to five times the impact speed of the raindrop, and are dispersed up to 1 m away from the parent plant, which is only a few cm high. Previous work investigating the mechanism of this remarkable dispersal predicted an optimum cup opening angle of around 40°, which matched reasonably well with experiments performed with 3D-printed splash cup models. Those experiments were done with off-center drop impacts on initially empty cups with no seeds. We discuss similar experiments for cups that are not initially empty, but rather contain seed mimics, water, or both seeds and water. For some of these realistic initial states results are strikingly different from empty cups. Connections to theory will also be discussed.

  6. Are splash plumes the origin of minor hotspots?

    Science.gov (United States)

    Davies, J. H.; Bunge, H.-P.

    2006-05-01

    It has been claimed that focused hot cylindrical upwelling plumes cause many of the surface volcanic hotspots on Earth. It has also been argued that they must originate from thermal boundary layers. In this paper, we present spherical simulations of mantle circulation at close to Earth-like vigor with significant internal heating. These show, in addition to thermal boundary layer plumes, a new class of plumes that are not rooted in thermal boundary layers. These plumes develop as instabilities from the edge of bowls of hot mantle, which are produced by cold downwelling material deforming hot sheets of mantle. The resulting bowl and plume structure can look a bit like the “splash” of a water droplet. These splash plumes might provide an explanation for some hotspots that are not underlain by thermal boundary layer sourced plumes and not initiated by large igneous provinces. We suggest that in Earth's mantle, lithospheric instabilities or small pieces of subducting slab could play the role of the model downwelling material in initiating splash plumes. Splash plumes would have implications for interpreting ocean-island basalt geochemistry, plume fixity, excess plume temperature, and estimating core heat flux. Improved seismic imaging will ultimately test this hypothesis.

  7. User manual for SPLASH (Single Panel Lamp and Shroud Helper).

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Marvin Elwood

    2006-02-01

    The radiant heat test facility develops test sets providing well-characterized thermal environments, often representing fires. Many of the components and procedures have become standardized to such an extent that the development of a specialized design tool to determine optimal configurations for radiant heat experiments was appropriate. SPLASH (Single Panel Lamp and Shroud Helper) is that tool. SPLASH is implemented as a user-friendly, Windows-based program that allows a designer to describe a test setup in terms of parameters such as number of lamps, power, position, and separation distance. This document is a user manual for that software. Any incidental descriptions of theory are only for the purpose of defining the model inputs. The theory for the underlying model is described in SAND2005-2947 (Ref. [1]). SPLASH provides a graphical user interface to define lamp panel and shroud designs parametrically, solves the resulting radiation enclosure problem for up to 2500 surfaces, and provides post-processing to facilitate understanding and documentation of analyzed designs.

  8. Effect of Seed Density on Splash Cup Seed Dispersal

    Science.gov (United States)

    Wigger, Patrick; Pepper, Rachel

    2017-11-01

    Splash cup plants are plants that utilize a small, mm-sized cup filled with seeds as a method of seed dispersal. The cup uses kinetic energy of an incident raindrop in order to project the seeds away from the plant up to 1 meter. The dispersal distance is important to ensure the offspring are not clustered too tightly to the parent plant. It has previously been found that a cup angle of 40 degrees to the horizontal is optimal for maximum dispersal of water from cups with no seeds. In this study we examine if the 40 degree cup is optimal for cups containing seeds with varying densities. We released uniform water drops above 5.0 mm 3D printed models of splash cups, using 1.0 mm plastic and glass microspheres of varying densities to simulate seeds. We observed the dispersal characteristics of each bead type by measuring the final seed locations after each splash, and by recording high speed video to determine the angle and velocity of the seeds as they exited the cup.

  9. Roughness influence on human blood drop spreading and splashing

    Science.gov (United States)

    Smith, Fiona; Buntsma, Naomi; Brutin, David

    2017-11-01

    The impact behaviour of complex fluid droplets is a topic that has been extensively studied but with much debate. The Bloodstain Pattern Analysis (BPA) community is encountering this scientific problem with daily practical cases since they use bloodstains as evidence in crime scene reconstruction. We aim to provide fundamental explanations in the study of blood drip stains by investigating the influence of surface roughness and wettability on the splashing limit of droplets of blood, a non-Newtonian colloidal fluid. Droplets of blood impacting perpendicularly different surfaces at different velocities were recorded. The recordings were analysed as well as the surfaces characteristics in order to find an empirical solution since we found that roughness plays a major role in the threshold of the splashing/non-splashing behaviour of blood compared to the wettability. Moreover it appears that roughness alters the deformation of the drip stains. These observations are key in characterising features of drip stains with the impacting conditions, which would answer some forensic issues.

  10. Research of low boom and low drag supersonic aircraft design

    Directory of Open Access Journals (Sweden)

    Feng Xiaoqiang

    2014-06-01

    Full Text Available Sonic boom reduction will be an issue of utmost importance in future supersonic transport, due to strong regulations on acoustic nuisance. The paper describes a new multi-objective optimization method for supersonic aircraft design. The method is developed by coupling Seebass–George–Darden (SGD inverse design method and multi-objective genetic algorithm. Based on the method, different codes are developed. Using a computational architecture, a conceptual supersonic aircraft design environment (CSADE is constructed. The architecture of CSADE includes inner optimization level and out optimization level. The low boom configuration is generated in inner optimization level by matching the target equivalent area distribution and actual equivalent area distribution. And low boom/low drag configuration is generated in outer optimization level by using NSGA-II multi-objective genetic algorithm to optimize the control parameters of SGD method and aircraft shape. Two objective functions, low sonic boom and low wave drag, are considered in CSADE. Physically reasonable Pareto solutions are obtained from the present optimization. Some supersonic aircraft configurations are selected from Pareto front and the optimization results indicate that the swept forward wing configuration has benefits in both sonic boom reduction and wave drag reduction. The results are validated by using computational fluid dynamics (CFD analysis.

  11. Modeling and simulation of the agricultural sprayer boom leveling system

    KAUST Repository

    Sun, Jian

    2011-01-01

    According to the agricultural precision requirements, the distance from sprayer nozzles to the corps should be kept between 50 cm to 70 cm. The sprayer boom also needs to be kept parallel to the field during the application process. Thus we can guarantee the quality of the chemical droplets distribution on the crops. In this paper we design a sprayer boom leveling system for agricultural sprayer vehicles combined with a four-rod linkage self-leveling suspension and electro-hydraulic auto-leveling system. The dynamic analysis shows that the suspension can realize an excellent self-leveling in a comparative small inclination range. In addition we build compensation controller for the electro-hydraulic system based on the mathematical model. With simulations we can optimize the performance of this controller to make sure a fast leveling response to the inclined sprayer boom. © 2011 IEEE.

  12. Numerical analysis of splashing fluid using hybrid method of mesh-based and particle-based modelings

    International Nuclear Information System (INIS)

    Tanaka, Nobuatsu; Ogawara, Takuya; Kaneda, Takeshi; Maseguchi, Ryo

    2009-01-01

    In order to simulate splashing and scattering fluid behaviors, we developed a hybrid method of mesh-based model for large-scale continuum fluid and particle-based model for small-scale discrete fluid particles. As for the solver of the continuum fluid, we adopt the CIVA RefIned Multiphase SimulatiON (CRIMSON) code to evaluate two phase flow behaviors based on the recent computational fluid dynamics (CFD) techniques. The phase field model has been introduced to the CRIMSON in order to solve the problem of loosing phase interface sharpness in long-term calculation. As for the solver of the discrete fluid droplets, we applied the idea of Smoothed Particle Hydrodynamics (SPH) method. Both continuum fluid and discrete fluid interact each other through drag interaction force. We verified our method by applying it to a popular benchmark problem of collapse of water column problems, especially focusing on the splashing and scattering fluid behaviors after the column collided against the wall. We confirmed that the gross splashing and scattering behaviors were well reproduced by the introduction of particle model while the detailed behaviors of the particles were slightly different from the experimental results. (author)

  13. Sonic boom research: TsAGI approach

    OpenAIRE

    Chernyshev, S. L.; Ivanteeva, L. G.; Kovalenko, V. V.; Teperin, L. L.; Chernyshev, S. L.; Ivanteeva, L. G.; Kovalenko, V. V.; Teperin, L. L.

    2000-01-01

    Research into sonic booms is indispensable for the future supersonic flight. In particular, the issue of sonic boom becomes a crucial problem when supersonic flights are over thickly populated areas. The TsAGI (Russia Central Aerohydrodynamic Institute) has been studying the sonic boom problem theoretically, experimentally and numerically since 1960. Prof. Zhirin of this institute has developed a theory of sonic boom by aircraft flying along any specified trajectory in non-homogeneous atmosph...

  14. Sonic boom predictions using a modified Euler code

    Science.gov (United States)

    Siclari, Michael J.

    1992-04-01

    The environmental impact of a next generation fleet of high-speed civil transports (HSCT) is of great concern in the evaluation of the commercial development of such a transport. One of the potential environmental impacts of a high speed civilian transport is the sonic boom generated by the aircraft and its effects on the population, wildlife, and structures in the vicinity of its flight path. If an HSCT aircraft is restricted from flying overland routes due to excessive booms, the commercial feasibility of such a venture may be questionable. NASA has taken the lead in evaluating and resolving the issues surrounding the development of a high speed civilian transport through its High-Speed Research Program (HSRP). The present paper discusses the usage of a Computational Fluid Dynamics (CFD) nonlinear code in predicting the pressure signature and ultimately the sonic boom generated by a high speed civilian transport. NASA had designed, built, and wind tunnel tested two low boom configurations for flight at Mach 2 and Mach 3. Experimental data was taken at several distances from these models up to a body length from the axis of the aircraft. The near field experimental data serves as a test bed for computational fluid dynamic codes in evaluating their accuracy and reliability for predicting the behavior of future HSCT designs. Sonic boom prediction methodology exists which is based on modified linear theory. These methods can be used reliably if near field signatures are available at distances from the aircraft where nonlinear and three dimensional effects have diminished in importance. Up to the present time, the only reliable method to obtain this data was via the wind tunnel with costly model construction and testing. It is the intent of the present paper to apply a modified three dimensional Euler code to predict the near field signatures of the two low boom configurations recently tested by NASA.

  15. Real Time Sonic Boom Display

    Science.gov (United States)

    Haering, Ed

    2014-01-01

    This presentation will provide general information about sonic boom mitigation technology to the public in order to supply information to potential partners and licensees. The technology is a combination of flight data, atmospheric data and terrain information implemented into a control room real time display for flight planning. This research is currently being performed and as such, any results and conclusions are ongoing.

  16. Realism Assessment of Sonic Boom Simulators

    Science.gov (United States)

    Sullivan, Brenda M.; Davies, Patrica; Hodgdon, Kthleen K.; Salamone, Joseph A., III; Pilon, Anthony

    2008-01-01

    Developments in small supersonic aircraft design are predicted to result in low-intensity sonic booms. Booms generated by current aircraft are similar to those that led to the ban on commercial supersonic fli ght over the US, so are unsuitable for parametric studies of psychoac oustic response to low-intensity booms. Therefore, simulators have be en used to study the impact of predicted low-intensity sonic booms. H owever, simulators have been criticized because, when simulating conv entional-level booms, the sounds were observed to be unrealistic by p eople experienced in listening to sonic booms. Thus, two studies were conducted to measure the perceived realism of three sonic boom simul ators. Experienced listeners rated the realism of conventional sonic boom signatures when played in these simulators. The effects on percei ved realism of factors such as duration of post-boom noise, exclusion of very low frequency components, inclusion of ground reflections, a nd type of simulator were examined. Duration of post-boom noise was f ound to have a strong effect on perceived realism, while type of simu lator had a weak effect. It was determined that post-boom noise had t o be at least 1.5 seconds long for the sound to be rated very realist ic. Loudness level did not affect realism for the range of sounds pla yed in the tests (80-93 dB ASEL).

  17. SPLASH-SXDF Multi-wavelength Photometric Catalog

    Science.gov (United States)

    Mehta, Vihang; Scarlata, Claudia; Capak, Peter; Davidzon, Iary; Faisst, Andreas; Hsieh, Bau Ching; Ilbert, Olivier; Jarvis, Matt; Laigle, Clotilde; Phillips, John; Silverman, John; Strauss, Michael A.; Tanaka, Masayuki; Bowler, Rebecca; Coupon, Jean; Foucaud, Sébastien; Hemmati, Shoubaneh; Masters, Daniel; McCracken, Henry Joy; Mobasher, Bahram; Ouchi, Masami; Shibuya, Takatoshi; Wang, Wei-Hao

    2018-04-01

    We present a multi-wavelength catalog in the Subaru/XMM-Newton Deep Field (SXDF) as part of the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH). We include the newly acquired optical data from the Hyper-Suprime-Cam Subaru Strategic Program, accompanied by IRAC coverage from the SPLASH survey. All available optical and near-infrared data is homogenized and resampled on a common astrometric reference frame. Source detection is done using a multi-wavelength detection image including the u-band to recover the bluest objects. We measure multi-wavelength photometry and compute photometric redshifts as well as physical properties for ∼1.17 million objects over ∼4.2 deg2, with ∼800,000 objects in the 2.4 deg2 HSC-Ultra-Deep coverage. Using the available spectroscopic redshifts from various surveys over the range of 0 catalog is a valuable, publicly available resource, perfectly suited for studying galaxies in the early universe and tracing their evolution through cosmic time.

  18. Splash-like marine biodiversity additions after the cambrian

    Directory of Open Access Journals (Sweden)

    Ruban Dmitry A.

    2015-01-01

    Full Text Available Some Phanerozoic biotic radiations in the marine realm led to marine biodiversity additions, i.e., increases in the global number of genera to unprecedented levels. Each of the two alternative biodiversity curves implies five post-Cambrian events of this kind, which coincided with parts of the biotic radiations. However, differences between these curves do not allow to find coherent marine biodiversity additions with the only exception of those occurred at the interval of the Great Ordovician Biodiversification. The attempted interpretations indicate that the marine biodiversity additions increased the number of marine genera by 10-30 % (from the previous unprecedented level to that new. All additions were relatively brief and occurred as splashes throughout the Phanerozoic. Peculiar intrinsic and extrinsic factors, as well as the speed of diversification should be considered when triggers of these events are looked for. Undoubtedly, splash-like marine biodiversity additions played an important role in the evolution of life in the sea, but a lot of research is required in order to understand their true nature.

  19. Investigation of the pathway of contaminated soil transported to plant surfaces by raindrop splash

    International Nuclear Information System (INIS)

    Dreicer, M.; Hakonson, T.E.; Whicker, F.W.; White, G.C.

    1983-01-01

    The environmental transport pathway of soil-borne radioisotopes to vegetation surfaces via raindrop splash was studied. The data show that soil can significantly contribute to the contamination found on plants. Further detailed study is needed to calculate the rate constant for the raindrop splash and retention pathways. 8 references, 1 figure

  20. Health risk assessment for splash parks that use rainwater as source water

    NARCIS (Netherlands)

    De Man, H.; Bouwknegt, M.; van Heijnsbergen, E.; Leenen, E. J T M; van Knapen, F.; de Roda Husman, A. M.

    2014-01-01

    In the Netherlands, rainwater becomes more and more popular as an economic and environmentally sustainable water source for splash parks, however, the associated public health risk and underlying risk factors are unknown. Since splash parks have been associated with outbreaks of infectious diseases,

  1. Risk of blood splashes to the eye during surgery | De Silva | South ...

    African Journals Online (AJOL)

    Background. With the advent of a new infectious era involving the HIV and hepatitis B and C viruses, concern has arisen about transmission of these viruses through ocular blood splashes during surgery. The purpose of the study was to determine the risk of ocular blood splashes to surgeons and their assistants during ...

  2. Sonic boom propagation through atmospheric turbulence

    OpenAIRE

    Yamashita, Hiroshi; Obayashi, Shigeru; 山下, 博; 大林, 茂

    2009-01-01

    The effect of the homogeneous atmospheric turbulence on the sonic boom propagation has been investigated. The turbulence field is represented by a finite sum of discrete Fourier modes based on the von Karman and Pao energy spectrum. The sonic boom signature is calculated by the modified Waveform Parameter Method, considering the turbulent velocities. The results show that in 59 % of the cases, the intensity of the sonic boom had decreased, and in other 41 % of the cases had increased the soni...

  3. Low Sonic Boom Design Activities at Boeing

    Science.gov (United States)

    Haglund, George T.

    1999-01-01

    Low sonic boom studies have continued during the last year with the goal of exploring the ability of practical airplane designs to achieve significantly reduced sonic boom-loudness with reasonable performance penalties. At the 1993 Sonic Boom Workshop, improvements to the low-boom design methods were described and early results of two low-boom configurations -935 and -936) were presented. Now that the low boom design methods are reasonably mature, recent design activities have broadened somewhat to explore refinements to the -935 and -936 designs. In this paper the results are reported of a detailed systems study and performance sizing of the -935 (Hybrid sonic boom waveform) and the -936 (Flat-top waveform). This analysis included a second design cycle for reduced cruise drag and balance considerations. Another design study was of a small-wing version of the -935. Finally, some preliminary results of the recent LARC UPWT test of the -935 configuration are given, along with a proposed alternative method for extrapolating wind tunnel pressure signatures to the ground. The various configurations studied is also summarized. The topics covered by this paper are as follows: Systems study results of the Baseline -939 and low boom configurations -935 and -936, Small wing derivative of the -935, Wind tunnel test results of the -935, Test-derived F-function and propagation to the ground, and Future considerations (boom-softened baseline, overwater issues, and operations).

  4. Bearings for the biomass boom

    Energy Technology Data Exchange (ETDEWEB)

    MacQueen, Duncan

    2011-03-15

    Biomass energy is booming –– more than two billion people depend on biomass for their energy and the International Energy Agency predicts that biomass' share of the global energy supply will treble by 2050. But in many developing countries it is still regarded as a traditional and dirty solution that is often criminalised, unsustainable and poorly paid. A more sophisticated approach that legalises and secures sustainable production by and for local people could help improve energy security, cut carbon emissions, protect forests and reduce poverty.

  5. Modeling and Analysis of Truck Mounted Concrete Pump Boom by Virtual Prototyping

    Directory of Open Access Journals (Sweden)

    Wu Ren

    2017-01-01

    Full Text Available By far there is lack of research on different working conditions between rigid and flexible dynamics of truck mounted concrete pump booms. First a 3D model has been established by using virtual prototyping technology of a 37 m long boom in Pro/Engineering software. Then the rigid body simulation model has been built. Next modal superimposition method is adopted to change the 4 rigid body booms into flexible ones. Kinematics law and dynamic characteristics of 4 common working conditions had been studied then. Next tip displacement and the first boom hydraulic cylinder force of the 4 working conditions between rigid and flexible models have been researched. Furthermore the first natural frequencies of the structure have been calculated. The results show that the frequency of the horizontal condition has the lowest of all and the roof condition has the largest of all. Besides the cylinder forces of the flexible model are larger than the corresponding rigid ones because of the flexible boom vibration. Finally an experiment has been done on a boom test rig which proved that the established simulation model is reasonable and the frequency results are correct. All of these provide design reference to mechanical manipulator as well as reducing product development cost of such mechanism.

  6. SWFSC/MMTD/AK: Structure of Populations, Level of Abundance, and Status of Humpbacks (SPLASH) 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This project was part of a larger international project (SPLASH) designed to estimate the abundance and determine the population structure for humpback whales...

  7. Kelvin-Helmholtz instability in an ultrathin air film causes drop splashing on smooth surfaces.

    Science.gov (United States)

    Liu, Yuan; Tan, Peng; Xu, Lei

    2015-03-17

    When a fast-moving drop impacts onto a smooth substrate, splashing will be produced at the edge of the expanding liquid sheet. This ubiquitous phenomenon lacks a fundamental understanding. Combining experiment with model, we illustrate that the ultrathin air film trapped under the expanding liquid front triggers splashing. Because this film is thinner than the mean free path of air molecules, the interior airflow transfers momentum with an unusually high velocity comparable to the speed of sound and generates a stress 10 times stronger than the airflow in common situations. Such a large stress initiates Kelvin-Helmholtz instabilities at small length scales and effectively produces splashing. Our model agrees quantitatively with experimental verifications and brings a fundamental understanding to the ubiquitous phenomenon of drop splashing on smooth surfaces.

  8. Beam Splashes seen by the CMS detector #RestartLHC 2017 (end of April 2017)

    CERN Multimedia

    Mc Cauley, Thomas; Zevi Della Porta, Giovanni

    2017-01-01

    CMS event display from LHC beam splash on Saturday, 29th April 2017. This is the first time the full detector has seen particles produced since the beginning of the Extended Year-End Technical Stop (EYETS) 2017. In contrast to proton-proton collisions where the particles come from the center of the detector, in splash events, particles traverse the detector horizontally from one side to the other.

  9. Beam Splashes seen by the CMS detector #RestartLHC 2018 (end of Mar 2018)

    CERN Multimedia

    Mc Cauley, Thomas; Olivito, Dominick

    2018-01-01

    CMS event displays from LHC beam splash on Friday, 30th March 2018. In contrast to proton-proton collisions where the particles come from the center of the detector, in splash events, particles traverse the detector horizontally from one side to the other. The time sampling for the picture, which is optimized for collisions at the center of the detector, amplifies the appearance of an asymmetric energy deposit in the end that the particles traverse last.

  10. Sonic Boom: Six Decades of Research

    Science.gov (United States)

    Maglieri, Domenic J.; Bobbitt, Percy J.; Plotkin, Kenneth J.; Shepherd, Kevin P.; Coen, Peter G.; Richwine, David M.

    2014-01-01

    Sonic booms generated by aircraft traveling at supersonic speeds have been the subject of extensive aeronautics research for over 60 years. Hundreds of papers have been published that document the experimental and analytical research conducted during this time period. The purpose of this publication is to assess and summarize this work and establish the state-of-the-art for researchers just entering the field, or for those interested in a particular aspect of the subject. This publication consists of ten chapters that cover the experimental and analytical aspects of sonic boom generation, propagation and prediction with summary remarks provided at the end of each chapter. Aircraft maneuvers, sonic boom minimization, simulation techniques and devices as well as human, structural, and other responses to sonic booms are also discussed. The geometry and boom characteristics of various low-boom concepts, both large civil transports and smaller business-jet concepts, are included. The final chapter presents an assessment of civilian supersonic overland flight and highlights the need for continued research and a low-boom demonstrator vehicle. Summary remarks are provided at the end of each chapter. The studies referenced in this publication have been drawn from over 500 references.

  11. Ash wettability conditions splash erosion in the postfire

    Science.gov (United States)

    Gordillo-Rivero, Ángel J.; de Celis, Reyes; García-Moreno, Jorge; Jiménez-Compán, Elizabeth; Alanís, Nancy; Cerdà, Artemi; Pereira, Paulo; Zavala, Lorena M.; Jordán, Antonio

    2015-04-01

    à and Doerr, 2008; Woods and Balfour, 2008; Zavala et al., 2009). The presence of an ash layer may be ephemeral, as it often is quickly removed or redistributed by water and wind erosion, animals or traffic (Zavala et al., 2009a). Many authors have observed that the capacity of ash to protect soil depends on properties as the topography, the meteorological conditions and the thickness of ash coverage (Cerdà and Doerr, 2008; Pereira et al., 2013; Woods and Balfour, 2010; Zavala et al., 2009). Taking this into account, in this study we hypothesized that the wettability / hydrophobicity of the ash layer may have a significant effect on the soil response to splash erosion. Therefore, the aim of this study is to evaluate the dispersion of sediments produced by the impact of raindrops in function of ash wettability after a prescribed fire at plot scale. 2. MATERIAL AND METHODS In 20 November 2012, a prescribed fire was carried out in an area located in the public mount "Las Navas", near Almaden de la Plata, Sevilla (approx. 37° 50' 44.44'' N / 6° 3' 7.44''W and 428 masl). Soils are acidic and shallow, developed from acidic metamorphic rocks (schists, slates and pyrophyllites). Vegetation is dominated by shrub legumes (Calicotome villosa and several species of Ulex and Genista). The experimental area was framed and plowed to eliminate the risk of fire spreading during the experiment. Previously to burn, level staffs were installed for determination of flame height. The temperature reached in the soil was monitored during the fire by a set of six thermocouples which were buried in soil (2 cm depth) and connected to a data-logger for monitoring the topsoil temperature every 60 s. The environmental conditions were also monitored during the experiment by a mobile weather station. At the moment of the ignition, the temperature was around 20 °C and the wind speed was near 0.0 m/s. After ignition, the experimental area was allowed to burn during 2.5 h. During burning, flames

  12. Negatively charged nanoparticles produced by splashing of water

    Directory of Open Access Journals (Sweden)

    H. Tammet

    2009-01-01

    Full Text Available The production of splashing-generated balloelectric intermediate ions was studied by means of mobility spectrometry in the atmosphere during the rain and in a laboratory experiment simulating the heavy rain. The partial neutralization of intermediate ions with cluster ions generated by beta rays suppressed the space charge of intermediate ions but preserved the shape of the mobility distribution. The balloelectric ions produced from the waterworks water of high TDS (Total Dissolved Solids had about the same mobilities as the ions produced from the rainwater of low TDS. This suggests that the balloelectric ions can be considered as singly charged water nanoparticles. By different measurements, the diameter mode of these particles was 2.2–2.7 nm, which is close to the diameter of 2.5 nm of the Chaplin's 280-molecule magic icosahedron superclusters. The measurements can be explained by a hypothesis that the pressure of saturated vapor over the nanoparticle surface is suppressed by a number of magnitudes due to the internal structure of the particles near the size of 2.5 nm. The records of the concentration bursts of balloelectric ions in the atmosphere are formally similar to the records of the nucleation bursts but they cannot be qualified as nucleation bursts because the particles are not growing but shrinking.

  13. ACCURATE OH MASER POSITIONS FROM THE SPLASH PILOT REGION

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Hai-Hua; Shen, Zhi-Qiang [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai, 200030 (China); Walsh, Andrew J.; Jordan, Christopher H. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth WA 6845 (Australia); Green, James A. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, PO Box 76, Epping, NSW 2121 (Australia); Breen, Shari L. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Dawson, J. R. [Department of Physics and Astronomy and MQ Research Centre in Astronomy, Astrophysics and Astrophotonics, Macquarie University, NSW 2109 (Australia); Ellingsen, Simon P. [School of Physical Sciences, Private Bag 37,University of Tasmania, Hobart 7001, TAS (Australia); Gómez, José F. [Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, E-18008, Granada (Spain); Lowe, Vicki; Jones, Paul A., E-mail: qiaohh@shao.ac.cn [Department of Astrophysics and Optic, School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia)

    2016-12-01

    We report on high spatial resolution observations, using the Australia Telescope Compact Array (ATCA), of ground-state OH masers. These observations were carried out toward 196 pointing centers previously identified in the Southern Parkes Large-Area Survey in Hydroxyl (SPLASH) pilot region, between Galactic longitudes of 334° and 344° and Galactic latitudes of −2° and +2°. Supplementing our data with data from the MAGMO (Mapping the Galactic Magnetic field through OH masers) survey, we find maser emission toward 175 of the 196 target fields. We conclude that about half of the 21 nondetections were due to intrinsic variability. Due to the superior sensitivity of the followup ATCA observations, and the ability to resolve nearby sources into separate sites, we have identified 215 OH maser sites toward the 175 fields with detections. Among these 215 OH maser sites, 111 are new detections. After comparing the positions of these 215 maser sites to the literature, we identify 122 (57%) sites associated with evolved stars (one of which is a planetary nebula), 64 (30%) with star formation, two sites with supernova remnants, and 27 (13%) of unknown origin. The infrared colors of evolved star sites with symmetric maser profiles tend to be redder than those of evolved star sites with asymmetric maser profiles, which may indicate that symmetric sources are generally at an earlier evolutionary stage.

  14. Real estate boom and export performance bust in Croatia

    Directory of Open Access Journals (Sweden)

    Marina Tkalec

    2014-06-01

    Full Text Available The goal of this research is to estimate the effect of resource reallocation from the manufacturing to the real estate economic sector on exporting activity in Croatia, a small open post-transition country that experienced a real estate boom during the previous decade. This paper follows the work by Égert and Kierzenkowski (2014 as we test the hypothesis that the real estate boom had an adverse impact on country’s export performance. For that purpose we use quarterly data ranging from 1Q1998 to 3Q2013, and estimate export equations using maximum likelihood and dynamic ordinary least squares estimators of cointegration. Our results indicate that the distortion of relative prices in favor of non-tradable sectors (construction and real estate, which is a direct by-product of the real estate boom, has had stifling effects on export performance. Our results also suggest that ailing cost competitiveness and governments’ inability to implement policies promoting private sector economic development adversely influenced export performance during the period analyzed. The basic conclusion of our research is that the expansion of a non-tradable sector in a country with limited supply of production factors can have a detrimental effect on the ability of the tradable sector to increase its output and compete in international markets.

  15. Internal Stellar Kinematics of M32 from the SPLASH Survey: Dark Halo Constraints

    Science.gov (United States)

    Howley, K. M.; Guhathakurta, P.; van der Marel, R.; Geha, M.; Kalirai, J.; Yniguez, B.; Kirby, E.; Cuillandre, J.-C.; Gilbert, K.

    2013-03-01

    As part of the SPLASH survey of the Andromeda (M31) system, we have obtained Keck/DEIMOS spectra of the compact elliptical (cE) satellite M32. This is the first resolved-star kinematical study of any cE galaxy. In contrast to most previous kinematical studies that extended out to r information to account statistically for M31 contamination. The rotation curve and velocity dispersion profile extend well beyond the radius (r ~ 150'') where the isophotes are distorted. Unlike NGC 205, another close dwarf companion of M31, M32's kinematics appear regular and symmetric and do not show obvious sharp gradients across the region of isophotal elongation and twists. We interpret M31's kinematics using three-integral axisymmetric dynamical equilibrium models constructed using Schwarzschild's orbit superposition technique. Models with a constant mass-to-light ratio can fit the data remarkably well. However, since such a model requires an increasing tangential anisotropy with radius, invoking the presence of an extended dark halo may be more plausible. Such an extended dark halo is definitely required to bind a half-dozen fast-moving stars observed at the largest radii, but these stars may not be an equilibrium component of M32. Data herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  16. Del Boom y otras onomatopeyas literarias

    Directory of Open Access Journals (Sweden)

    Jorge Iván Parra Londoño

    2016-03-01

    Full Text Available Este artículo trata de examinar los alcances literarios del llamado Boom latinoamericano, a medio siglo de su estallido, las cuatro obras más representativas y sus respectivos autores, además de proponer un quinto autor, según la invitación que hiciera en su momento el crítico Ángel Rama. Por otro lado, evalua la respuesta literaria por parte del Post Boom, analizando sus características y su vigencia y, de manera concomitante, los movimientos anejos o posteriores a dicho movimiento, como el Crack y la Generación Granta. A manera de propuesta, se pondrán a consideración treinta autores como integrantes del Post Boom y una novela de Carlos Fuentes como el “crash” del Boom. Por último, presenta un breve vistazo a la narrativa española paralela a los mencionados movimientos.

  17. Structural Analysis of Field Sprayer Booms

    OpenAIRE

    KOÇ, Caner

    2017-01-01

    In this paper, structural analysis of a 21 meters wide field sprayer boom, designed for precision agricultureapplications, was conducted with finite element analysis. G-programming language, a data acquisition board andan inductive force transducer were used to measure the forces acting on the boom arms. An experimental setup,developed in a laboratory environment, was able to measure and record various forces in 5 miliseconds intervals.An ANSYS model was developed to analyze the forces record...

  18. Aerial Refueling Boom/Receptacle Guide

    Science.gov (United States)

    2017-07-28

    proprietary , sensitive, classified or otherwise restricted information. ARSAG documents, as prepared, are not DOD, MOD or NATO standards, but provide...Equipment Characteristics 20. NATO STANAG 7191 Air-to-Air Refuelling Equipment: Boom-Receptacle System and Interface Requirements, Edition 1, 3 June 2013...Aerial Refueling Boom Feasibility Study, Dated Jan 1972, Contractor: The Boeing Company , Wichita Division. 28. Specification Number ZA015800, “KC-10A

  19. Sleipner mishap jolts booming Norway

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This paper reports on Norway's buoyant offshore industry that was stunned when the concrete substructure for Sleipner natural gas field's main production platform sank in the Grandsfjord off Stavanger late last month. The accident, a blow to Norway's gas sales program in Europe, came with offshore activity in the Norwegian North Sea moving into a new boom period. Currently, 10 oil and gas fields are under development, and several projects are on the drawing board. Aker Oil and Gas, a leading offshore firm, says the country's construction industry will be working at capacity for the next 4 years. Norwegian oil production has been hovering just below 2 million b/d since the beginning of this year, making Norway the North Sea's largest producer, a position formerly held by the U.K. Gas production averages about 3 bcfd. With European gas demand sharply increasing, Norway is under pressure to increase output from new fields in the mid to late 1990s. The Sleipner setback forces state owned Den norske stats oljeselskap AS (Statoil) to cast around for supplies. Sleipner was to have begun deliveries to a consortium of continental gas companies in October 1993. Statoil believes it can fill the gap from existing fields in Norwegian waters

  20. FORMING CHONDRULES IN IMPACT SPLASHES. II. VOLATILE RETENTION

    Energy Technology Data Exchange (ETDEWEB)

    Dullemond, Cornelis Petrus; Harsono, Daniel; Stammler, Sebastian Markus [Institute for Theoretical Astrophysics, Heidelberg University, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany); Johansen, Anders [Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, SE-22100 Lund (Sweden)

    2016-11-20

    Solving the mystery of the origin of chondrules is one of the most elusive goals in the field of meteoritics. Recently, the idea of planet(esimal) collisions releasing splashes of lava droplets, long considered out of favor, has been reconsidered as a possible origin of chondrules by several papers. One of the main problems with this idea is the lack of quantitative and simple models that can be used to test this scenario by directly comparing to the many known observables of chondrules. In Paper I of this series, we presented a simple thermal evolution model of a spherically symmetric expanding cloud of molten lava droplets that is assumed to emerge from a collision between two planetesimals. The production of lava could be either because the two planetesimals were already in a largely molten (or almost molten) state due to heating by {sup 26}Al, or due to impact jetting at higher impact velocities. In the present paper, number II of this series, we use this model to calculate whether or not volatile elements such as Na and K will remain abundant in these droplets or whether they will get depleted due to evaporation. The high density of the droplet cloud (e.g., small distance between adjacent droplets) causes the vapor to quickly reach saturation pressure and thus shuts down further evaporation. We show to what extent, and under which conditions, this keeps the abundances of these elements high, as is seen in chondrules. We find that for most parameters of our model (cloud mass, expansion velocity, initial temperature) the volatile elements Mg, Si, and Fe remain entirely in the chondrules. The Na and K abundances inside the droplets will initially stay mostly at their initial values due to the saturation of the vapor pressure, but at some point start to drop due to the cloud expansion. However, as soon as the temperature starts to decrease, most or all of the vapor recondenses again. At the end, the Na and K elements retain most of their initial abundances, albeit

  1. Design of Experiments for Both Experimental and Analytical Study of Exhaust Plume Effects on Sonic Boom

    Science.gov (United States)

    Castner, Raymond S.

    2009-01-01

    Computational fluid dynamics (CFD) analysis has been performed to study the plume effects on sonic boom signature for isolated nozzle configurations. The objectives of these analyses were to provide comparison to past work using modern CFD analysis tools, to investigate the differences of high aspect ratio nozzles to circular (axisymmetric) nozzles, and to report the effects of under expanded nozzle operation on boom signature. CFD analysis was used to address the plume effects on sonic boom signature from a baseline exhaust nozzle. Nearfield pressure signatures were collected for nozzle pressure ratios (NPRs) between 6 and 10. A computer code was used to extrapolate these signatures to a ground-observed sonic boom N-wave. Trends show that there is a reduction in sonic boom N-wave signature as NPR is increased from 6 to 10. As low boom designs are developed and improved, there will be a need for understanding the interaction between the aircraft boat tail shocks and the exhaust nozzle plume. These CFD analyses will provide a baseline study for future analysis efforts. For further study, a design of experiments has been conducted to develop a hybrid method where both CFD and small scale wind tunnel testing will validate the observed trends. The CFD and testing will be used to screen a number of factors which are important to low boom propulsion integration, including boat tail angle, nozzle geometry, and the effect of spacing and stagger on nozzle pairs. To design the wind tunnel experiment, CFD was instrumental in developing a model which would provide adequate space to observe the nozzle and boat tail shock structure without interference from the wind tunnel walls.

  2. Sonic Boom Generated by Reentry of Mir

    Science.gov (United States)

    Moody, D. M.

    2002-09-01

    The Russian space station, Mir, was actively deorbited to impact in the South Pacific on 23 March 2001. Mir was the largest body in Earth orbit ever to be deorbited in a controlled fashion. As such, it provided a unique opportunity to observe, at a known time and location, what happens to such a large object as it re-enters the earth's atmosphere. The reentry and breakup were videotaped from the Fiji Sheraton hotel by a CNN cameraman. About four to five minutes after the streaking Mir debris left his view, he described hearing a number of sonic booms which were generated by pieces of the wreckage. This report contains the camera-man's description of what he heard and a calculation of the sonic boom amplitude and duration which would have been generated by a single Mir module on its reentry trajectory. Results of the calculation are consistent with the reported estimated time of boom arrival past visual sighting. However, no actual measurements were made at the hotel of the boom strength (sound level.) Thus the code results for boom amplitude cannot be quantitatively verified.

  3. Optical MEMS: boom, bust and beyond

    Science.gov (United States)

    Ramani, Chandra Mouli

    2005-10-01

    Optical Telecommunications bandwidth, spurred by the growth of the internet, experienced unprecedented growth in the late 1990's. The creation of new enterprises was vast and the expansion of established component, system and services companies was also breathtaking. This period of speculative growth was followed in 2001-2004 by one of the most significant market crashes in history. While $20B of venture capital was invested in optical telecom in the last 10 years, the vast majority of that has been written off in the last four. Countless start-ups inaugurated with great fanfare at the end of the 20th century were unceremoniously shut down at the start of the 21st. (1) As in all speculative bubbles, innovative technologies were born and buried. Nonetheless, new capabilities emerge from the chaos and disruption; one such example is the advent of Optical MEMS (MOEMS). Its development was vigorously pursued in both academic and corporate laboratories during the boom and, in the author's view; MOEMS constitutes a powerful and versatile tool set that is an invaluable residual of the last few years. In Telecommunications, MOEMS has proven to be the technology of choice for many optical switching and wavelength management applications. (2) Variable Optical Attenuators (VOA), Wavelength Blockers (WB), Dynamic Gain Equalizers (DGE), and most recently Wavelength Selective Switches (WSS) are being used in the numerous recent network deployments. Moreover, agile networks of the future will have MOEMS at every node. This presentation will provide an overview of the history of MOEMS in Telecommunications, discuss its byproducts and project the future of the technology.

  4. Constraints on the Formation of M31’s Stellar Halo from the SPLASH Survey

    Directory of Open Access Journals (Sweden)

    Karoline Gilbert

    2017-09-01

    Full Text Available The SPLASH (Spectroscopic and Photometric Landscape of Andromeda’s Stellar Halo Survey has observed fields throughout M31’s stellar halo, dwarf satellites, and stellar disk. The observations and derived measurements have either been compared to predictions from simulations of stellar halo formation or modeled directly in order to derive inferences about the formation and evolution of M31’s stellar halo. We summarize some of the major results from the SPLASH survey and the resulting implications for our understanding of the build-up of M31’s stellar halo.

  5. Specialized CFD Grid Generation Methods for Near-Field Sonic Boom Prediction

    Science.gov (United States)

    Park, Michael A.; Campbell, Richard L.; Elmiligui, Alaa; Cliff, Susan E.; Nayani, Sudheer N.

    2014-01-01

    Ongoing interest in analysis and design of low sonic boom supersonic transports re- quires accurate and ecient Computational Fluid Dynamics (CFD) tools. Specialized grid generation techniques are employed to predict near- eld acoustic signatures of these con- gurations. A fundamental examination of grid properties is performed including grid alignment with ow characteristics and element type. The issues a ecting the robustness of cylindrical surface extrusion are illustrated. This study will compare three methods in the extrusion family of grid generation methods that produce grids aligned with the freestream Mach angle. These methods are applied to con gurations from the First AIAA Sonic Boom Prediction Workshop.

  6. Advanced Deployable Shell-Based Composite Booms for Small Satellite Structural Applications Including Solar Sails

    Science.gov (United States)

    Fernandez, Juan M.

    2017-01-01

    State of the art deployable structures are mainly being designed for medium to large size satellites. The lack of reliable deployable structural systems for low cost, small volume, rideshare-class spacecraft severely constrains the potential for using small satellite platforms for affordable deep space science and exploration precursor missions that could be realized with solar sails. There is thus a need for reliable, lightweight, high packaging efficiency deployable booms that can serve as the supporting structure for a wide range of small satellite systems including solar sails for propulsion. The National Air and Space Administration (NASA) is currently investing in the development of a new class of advanced deployable shell-based composite booms to support future deep space small satellite missions using solar sails. The concepts are being designed to: meet the unique requirements of small satellites, maximize ground testability, permit the use of low-cost manufacturing processes that will benefit scalability, be scalable for use as elements of hierarchical structures (e.g. trusses), allow long duration storage, have high deployment reliability, and have controlled deployment behavior and predictable deployed dynamics. This paper will present the various rollable boom concepts that are being developed for 5-20 m class size deployable structures that include solar sails with the so-called High Strain Composites (HSC) materials. The deployable composite booms to be presented are being developed to expand the portfolio of available rollable booms for small satellites and maximize their length for a given packaged volume. Given that solar sails are a great example of volume and mass optimization, the booms were designed to comply with nominal solar sail system requirements for 6U CubeSats, which are a good compromise between those of smaller form factors (1U, 2U and 3U CubeSats) and larger ones (12 U and 27 U future CubeSats, and ESPA-class microsatellites). Solar

  7. Disturbance of sleep by sonic booms.

    Science.gov (United States)

    Griefahn, B; Jansen, G

    1975-05-01

    After a pilot study (2 subjects, 19 nights) we tested two different subjects during 57 nights, administering sonic booms (1 mb, 300 ms; sound level of sonic boom in the bedroom 80-85 dB (A) and recording EEG and peripheral blood volume. After 7 nights without noise, 30 nights with either 2 or 4 sonic booms (alternately) were applied. After 10 more nights without noise, four nights with 8 and 16 bangs followed alternately. The last 6 nights were used as a comparison phase. Results showed that distrubance was obvious during all periods of noise. No adaptation could be observed during any of the experiments. On the contrary, during the night with 4 bangs there was a tendency for compensation, e.g., in the last two thirds of nights with 4 bangs, the total time of deep sleep was comparable with the nights without any noise.

  8. Experimental and Computational Sonic Boom Assessment of Lockheed-Martin N+2 Low Boom Models

    Science.gov (United States)

    Cliff, Susan E.; Durston, Donald A.; Elmiligui, Alaa A.; Walker, Eric L.; Carter, Melissa B.

    2015-01-01

    Flight at speeds greater than the speed of sound is not permitted over land, primarily because of the noise and structural damage caused by sonic boom pressure waves of supersonic aircraft. Mitigation of sonic boom is a key focus area of the High Speed Project under NASA's Fundamental Aeronautics Program. The project is focusing on technologies to enable future civilian aircraft to fly efficiently with reduced sonic boom, engine and aircraft noise, and emissions. A major objective of the project is to improve both computational and experimental capabilities for design of low-boom, high-efficiency aircraft. NASA and industry partners are developing improved wind tunnel testing techniques and new pressure instrumentation to measure the weak sonic boom pressure signatures of modern vehicle concepts. In parallel, computational methods are being developed to provide rapid design and analysis of supersonic aircraft with improved meshing techniques that provide efficient, robust, and accurate on- and off-body pressures at several body lengths from vehicles with very low sonic boom overpressures. The maturity of these critical parallel efforts is necessary before low-boom flight can be demonstrated and commercial supersonic flight can be realized.

  9. 77 FR 23120 - Special Local Regulations; Lowcountry Splash Open Water Swim, Wando River and Cooper River, Mount...

    Science.gov (United States)

    2012-04-18

    ...-AA08 Special Local Regulations; Lowcountry Splash Open Water Swim, Wando River and Cooper River, Mount... Special Local Regulations; Lowcountry Splash Open Water Swim, Wando River and Cooper River, Mount Pleasant... water swim, starts at Hobcaw Yacht Club on the Wando River, in approximate position 32[deg]49'19'' N, 79...

  10. Innovative Escapement-Based Mechanism for Micro-Antenna Boom Deployment

    Science.gov (United States)

    Tokarz, Marta; Grygorczuk, Jerzy; Jarzynka, Stanislaw; Gut, Henryk

    2014-01-01

    This paper presents the prototype of a tubular boom antenna developed for the Polish BRITE-PL satellite by the Space Research Center of the Polish Academy of Sciences (CBK PAN). What is unique about our work is that we developed an original type of the tubular boom antenna deployment mechanism that can be used widely as a basic solution for compact electrical antennas, booms deploying sensitive instruments, ultra-light planetary manipulators etc. The invented electromagnetic driving unit provides a dual complementary action - it adds extra energy to the driving spring, making the system more reliable, and at the same time it moderates the deployment speed acting as a kind of damper. That distinguishing feature predetermines the mechanism to be applied wherever the dynamic nature of a spring drive introducing dangerous vibrations and inducing severe local stress in the structure needs to be mitigated. Moreover, the paper reveals a product unique in Europe - a miniature beryllium bronze tubular boom free of geometry and strain defects, which is essential for stiffness and fatigue resistance. Both the deployment mechanism and the technology of tubular boom manufacturing are protected by patent rights.

  11. Environmental Pollution: Noise Pollution - Sonic Boom

    Science.gov (United States)

    1977-06-01

    UNCLASSIFIED AD-A041 400 DDC/BIB-77/06 ENVIRONMENTAL POLLUTION NOISE POLLUTION SONIC BOOM A DDC BIBLIOGRAPHY DDC-TAS Cameron Station Alexandria, Va...rn7Sttio 658S-A041 400 4 TITLE xand r.VuhtlVlia) 2 TA i b- 1iblog ra ph y ENVIRONMENTAL POLLUTION : --. Apr-l IM59-Jul, 7NOISE POLLUTION -SONIC BOOM. 1,976...BIBLIOGRAPHY SEARCH CONTROL NO. /2OM09 AD- 769 970 20/1 1/3 DEFENSE UOCUMENTATION CENTER ALEXANDRIA VA ENVIRONMENTAL POLLUTION : NOISE POLLUTION

  12. A Mystery Unraveled: Booming Sand Dunes

    Science.gov (United States)

    Vriend, N. M.; Hunt, M. L.; Clayton, R. W.

    2007-12-01

    "Booming" sand dunes have intrigued travelers and scientist for centuries. These dunes emit a persistent, low-frequency sound during a slumping event or a natural avalanche on the leeward face of the dune. The sound can last for several minutes and be audible from miles away. The resulting acoustic emission is characterized by a dominant audible frequency (70 - 105 Hz) and several higher harmonics. In the work of Vriend et al. (2007), seismic refraction experiments proved the existence of a multi-layer internal structure in the dune that acts as a waveguide for the acoustic energy. Constructive interference between the reflecting waves enables the amplification and sets the frequency of each boom. A relationship was established that correctly predicts the measured frequency in terms of the thickness (~ 2.0 m) and the seismic body wave velocity of the loose, dry surficial layer (~ 240 m/s) and the substrate half-space (~ 350 m/s). The current work highlights additional measurements and simulations supporting the waveguide model for booming sand dunes. Experiments with ground penetrating radar continuously display the subsurface features which confirm the layered subsurface structure within the dune. Cross-correlation analysis shows that the booming sound propagates at speeds close to the measured body wave velocity. Squeaking sounds, which are generated during the onset of the slide and precede the sustained booming emission, have been found to have distinctly different characteristics. These short bursts of sound are emitted at a lower frequency (50 - 65 Hz) and propagate at a lower propagation speed (125 m/s) than the booming emission. The acoustic and elastic wave propagation in the dune has been simulated with a finite difference code. The interaction between the air and the ground produces a coupling wave along the surface. The reflections in the surficial layer propagate in a dispersive band at a group velocity that is slower than the phase velocity of the

  13. 14 CFR 91.817 - Civil aircraft sonic boom.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Civil aircraft sonic boom. 91.817 Section....817 Civil aircraft sonic boom. (a) No person may operate a civil aircraft in the United States at a... sonic boom to reach the surface within the United States; and (2) The operator complies with the flight...

  14. Is splash erosion potential species specific? Measuring of splash erosion potential under forest in different succession stages along a biodiversity gradient in the humid subtropics

    Science.gov (United States)

    Geißler, C.; Kühn, P.; Scholten, T.

    2009-04-01

    It is widely accepted that (forest) vegetation is a key control for the type and intensity of soil erosion. The current paradigm is that natural or quasi-natural vegetation protects the soil from erosion and that agricultural vegetation or land use generally enhances erosion. The latter was in focus of most research during the last decades and less interest was paid on natural systems, which are more difficult to study. Nevertheless, afforestation is widely used as a measure of soil protection against soil erosion. Rainfall can be highly erosive particularly in the humid subtropics. Regarding climate change, also precipitation regime may change in direction to even more severe storms and higher rainfall intensities; it is a research field of growing importance. Key mechanisms of a vegetation cover in reducing or enhancing erosion are modifications of drop-size distribution, retention of raindrop impact on the soil and changes in amount and spatial distribution of rainfall at the ground surface. Controlling determinants are rainfall intensity, drop size distribution, drop fall velocity, height of the canopy as well as density of the canopy, crown and leaf traits, LAI and coverage by a litter layer. Large drops are supposed to be significant sources of splash detachment in forests (Brandt 1989; Vis 1986). However, the mechanisms of reducing (or enhancing?) splash detachment under forest in relation to species richness and species composition are not well understood. Some studies indicate that raindrop impact is species specific (Calder 2001; Nanko et al. 2006) and some neglect the effects of species specific impacts (Foot & Morgan 2005). Our research uses different methods of rainfall characterization (splash cups, tipping-bucket rain gauge, laser distrometer) to reveal the described mechanisms from the canopy through different vegetation layers to the ground. First results of splash cup measurements (revised after Ellison 1947) show that sand loss under vegetation

  15. Effects of Rainfall Intensity and Slope Angle on Splash Erosion in ...

    African Journals Online (AJOL)

    Global Journal of Pure and Applied Sciences ... Soil erosion is a critical global environmental problem, especially in the developing countries including Nigeria. In the humid and ... Factors of slope angle, rainfall amount, and intensity, and total kinetic energy were regressed against directional components of splash.

  16. The Effects of Mulch Cover on Splash Erosion in Makurdi Town ...

    African Journals Online (AJOL)

    Soil erosion has continued to be a serious environmental problem, particularly among the farming communities. In Benue State, the dominant economic activity is subsistence farming which is done under sub humid rainfall conditions. Splash erosion resulting from intense rainfall therefore poses severe problems that can be ...

  17. Babies Bottom Out--A 'Maybe Boom'

    Science.gov (United States)

    Science News, 1977

    1977-01-01

    Data for the period September 1976 through April 1977 indicate a rise in the United States birth rate; however, the rate is still below the replacement level. It is speculated that the increase is an "echo" effect to the post-World War II baby boom which peaked in 1957. (SL)

  18. Concorde sonic booms as an atmospheric probe.

    Science.gov (United States)

    Balachandran, N K; Donn, W L; Rind, D H

    1977-07-01

    Infrasound generated by the sonic boom from the inbound Concorde supersonic transport is recorded at Palisades, New York (Lamont-Doherty Geological Observatory), as a series of impulses from distances varying from 165 to about 1000 kilometers. Refraction effects determined by temperature and wind conditions return the signal to the surface from both stratospheric (40 to 50 kilometers) and thermospheric (100 to 130 kilometers) levels. The frequency of the recorded signal is a function of the level of reflection; the frequency decreases from impulse stretching as the atmosphere becomes more rarified relative to the sound pressure. The horizontal trace velocity of the signal across the array of instruments is equal to the acoustic velocity at the reflection level. The sonic boom can thus be used to provide temperature-wind parameters at reflection levels estimated from the signal frequency. Daily observed signal variations have indicated significant variations in these parameters.

  19. Flow distortion on boom mounted cup anemometers

    DEFF Research Database (Denmark)

    Lindelöw, Per Jonas Petter; Friis Pedersen, Troels; Gottschall, Julia

    In this report we investigate on wind direction dependent errors in the measurement of the horizontal wind speed by boom mounted cup anemometers. The boom mounting on the studied lattice tower is performed according to IEC standard design rules, yet, larger deviations than predicted by flow models...... are observed. The errors on the measurements are likely caused by an underestimation of the flow distortions around the tower. In this paper an experimental method for deriving a correction formula and an in-field calibration is suggested. The method is based on measurements with two cup anemometers mounted...... in the measurement of wind turbine power performance, wind resource assessment and for providing purposeful in-field comparisons between different sensors, e.g. lidar anemometers. With the proposed method, direction dependent errors can be extracted and the mast flow distortion effect on the wind measurements...

  20. High-Quality Seismic Observations of Sonic Booms

    Science.gov (United States)

    Wurman, Gilead; Haering, Edward A., Jr.; Price, Michael J.

    2011-01-01

    The SonicBREWS project (Sonic Boom Resistant Earthquake Warning Systems) is a collaborative effort between Seismic Warning Systems, Inc. and NASA Dryden Flight Research Center. This project aims to evaluate the effects of sonic booms on Earthquake Warning Systems in order to prevent such systems from experiencing false alarms due to sonic booms. The airspace above the Antelope Valley, California includes the High Altitude Supersonic Corridor and the Black Mountain Supersonic Corridor. These corridors are among the few places in the US where supersonic flight is permitted, and sonic booms are commonplace in the Antelope Valley. One result of this project is a rich dataset of high-quality accelerometer records of sonic booms which can shed light on the interaction between these atmospheric phenomena and the solid earth. Nearly 100 sonic booms were recorded with low-noise triaxial MEMS accelerometers recording 1000 samples per second. The sonic booms had peak overpressures ranging up to approximately 10 psf and were recorded in three flight series in 2010 and 2011. Each boom was recorded with up to four accelerometers in various array configurations up to 100 meter baseline lengths, both in the built environment and the free field. All sonic booms were also recorded by nearby microphones. We present the results of the project in terms of the potential for sonic-boom-induced false alarms in Earthquake Warning Systems, and highlight some of the interesting features of the dataset.

  1. Simple process-led algorithms for simulating habitats (SPLASH v.1.0): robust indices of radiation, evapotranspiration and plant-available moisture

    Science.gov (United States)

    Davis, Tyler W.; Prentice, I. Colin; Stocker, Benjamin D.; Thomas, Rebecca T.; Whitley, Rhys J.; Wang, Han; Evans, Bradley J.; Gallego-Sala, Angela V.; Sykes, Martin T.; Cramer, Wolfgang

    2017-02-01

    Bioclimatic indices for use in studies of ecosystem function, species distribution, and vegetation dynamics under changing climate scenarios depend on estimates of surface fluxes and other quantities, such as radiation, evapotranspiration and soil moisture, for which direct observations are sparse. These quantities can be derived indirectly from meteorological variables, such as near-surface air temperature, precipitation and cloudiness. Here we present a consolidated set of simple process-led algorithms for simulating habitats (SPLASH) allowing robust approximations of key quantities at ecologically relevant timescales. We specify equations, derivations, simplifications, and assumptions for the estimation of daily and monthly quantities of top-of-the-atmosphere solar radiation, net surface radiation, photosynthetic photon flux density, evapotranspiration (potential, equilibrium, and actual), condensation, soil moisture, and runoff, based on analysis of their relationship to fundamental climatic drivers. The climatic drivers include a minimum of three meteorological inputs: precipitation, air temperature, and fraction of bright sunshine hours. Indices, such as the moisture index, the climatic water deficit, and the Priestley-Taylor coefficient, are also defined. The SPLASH code is transcribed in C++, FORTRAN, Python, and R. A total of 1 year of results are presented at the local and global scales to exemplify the spatiotemporal patterns of daily and monthly model outputs along with comparisons to other model results.

  2. LHC Beam Splash seen by the ATLAS detector, 7 Apr 2015 - Run 260466 - event 22425

    CERN Multimedia

    Adam Bourdarios, Claire

    2015-01-01

    Event display of one of the collimator "splash" event seen by the ATLAS experiment in LHC Run-2 , on Tuesday April the 7th : event 22425, run 260466. The collimator position is 140m in front of the ATLAS interaction point. The spray of particles enters ATLAS from the left hand side of the picture. The length of the yellow bars indicates the energy deposited in the ATLAS calorimeter.

  3. Baby Boom, Asset Market Meltdown and Liquidity Trap

    OpenAIRE

    Junning Cai

    2004-01-01

    A so-called “asset market meltdown hypothesis” predicts that baby boomers’ large savings will drive asset market booms that will eventually collapse because of the boomers’ large retirement dissavings. As good news to baby boomers, our analysis shows that this meltdown hypothesis is fundamentally flawed; and baby-boom-driven asset market booms may not necessarily collapse. However, bad news is that, in the case where meltdowns are about to happen, forward-looking baby boomers’ attempts to esc...

  4. Development of a sonic boom measurement system at JAXA

    OpenAIRE

    VEGGEBERG, Kurt

    2012-01-01

    International audience; The Japan Aerospace Exploration Agency (JAXA) is actively conducting supersonic transport research toward the realization of civil supersonic aircraft. Technology that precisely measures sonic booms is essential to demonstrating JAXA’s sonic boom reduction concept in the planned drop test of a research aircraft. This is a part of the D-SEND Program (Drop Test for Simplified Evaluation of Non-Symmetrically Distributed sonic boom). Capturing detailed multichannel sonic b...

  5. BRAZILIAN ECONOMY’S BOOM

    Directory of Open Access Journals (Sweden)

    Gheorghe CARALICEA MĂRCULESCU

    2010-09-01

    Full Text Available Brazil owns an economy directed towards the free market and the export and nowadays it is on the 9th place in the world and on the 1sr place in frame of the countries in Latin America. Internal economy: The service sector has the biggest weight of 67.7% in PIB frame followed by the industrial one with a share of 25.8%. The agriculture represents only 6.5% of PIB. The manpower owned by Brazil is around 95 million (from a total population of about 195 million inhabitants shared as follows: 20% in agriculture, 14% in industry and 66% in service sector. Due to the scientific and technological development of Brazil, this country is very attractive for the foreign investors, the average being somewhere around 2- billion $ comparing to the average value of 2 billion $ according to the years 1990 – 2000. External economy: Lula administration used the solid increase of the global demand in the last years in order to decrease the external duty, to smooth the profile of the date of payment of the debt and to improve the interest dynamics and the currency. The massive capital influxes have led to the increase of the currency reserves at 245.8 billion $ (the equivalent of the importers’ value for more than a year. However, the current account deficit will reach about 3.5% of PIB, and even if the foreign direct investments could not cover this deficit, we do not see any problems at horizon in its financing. Fiscal sector: even if the government has managed to maintain most of the macro-economical indicators in positive values, the lack of certain tools of limiting the public expenditures was translated by a continuous increase and a damage of the report between the public debt and PIB across the last years. Actually, the gross public debt (63% of PIB in 2009 stays at a relatively big level comparing to other countries whose credit ranking is at least equal to BBB-. In addition, at a level of 10% of PIB, the financing needs of the budgetary sector

  6. A Study of Reflected Sonic Booms Using Airborne Measurements

    Science.gov (United States)

    Kantor, Samuel R.; Cliatt, Larry J.

    2017-01-01

    In support of ongoing efforts to bring commercial supersonic flight to the public, the Sonic Booms in Atmospheric Turbulence (SonicBAT) flight test conducted at NASA Armstrong Flight Research Center. During this test, airborne sonic boom measurements were made using an instrumented TG-14 motor glider, called the Airborne Acoustic Measurement Platform (AAMP).During the flight program, the AAMP was consistently able to measure the sonic boom wave that was reflected off of the ground, in addition to the incident wave, resulting in the creation of a completely unique data set of airborne sonic boom reflection measurements.

  7. Performance of floating oil booms in unsheltered waters

    Science.gov (United States)

    Iglesias, Gregorio; Castro, Alberte

    2013-04-01

    Oil booms are a fundamental tool to diminish the impact of an oil spill. They tend to perform reasonably well in sheltered waters, e.g. within a harbour. However, their performance is often inadequate in open water conditions, under waves, winds and currents. And it is precisely in those conditions that they are needed if oil slicks are to be prevented from reaching certain particularly sensitive areas, such as estuaries, rias, etc. (Castro et al., 2010; Iglesias et al., 2010). In this work the performance of floating oil booms under waves and currents is assessed on the basis of laboratory experiments carried out in a state-of-the-art wave-current flume. Different oil boom models are used, representative of booms with long and short skirts and with different weights. The results show that different booms behave very differently under waves and currents, hence the importance of selecting the boom design that is appropriate for the actual conditions under which it will have to contain the oil slick. Thus, different oil booms should be used for different areas. References A. Castro, G. Iglesias, R. Carballo, J.A. Fraguela, 2010. Floating boom performance under waves and currents, Journal of Hazardous Materials 174, 226-235 G. Iglesias, A.Castro, J.A.Fraguela, 2010. Artificial intelligence applied to floating boom behavior under waves and currents, Ocean Engineering 37, 1513-1521.

  8. Slot Nozzle Effects for Reduced Sonic Boom on a Generic Supersonic Wing Section

    Science.gov (United States)

    Caster, Raymond S.

    2010-01-01

    NASA has conducted research programs to reduce or eliminate the operational restrictions of supersonic aircraft over populated areas. Restrictions are due to the disturbance from the sonic boom, caused by the coalescence of shock waves formed off the aircraft. Results from two-dimensional computational fluid dynamic (CFD) analyses (performed on a baseline Mach 2.0 nozzle in a simulated Mach 2.2 flow) indicate that over-expanded and under-expanded operation of the nozzle has an effect on the N-wave boom signature. Analyses demonstrate the feasibility of reducing the magnitude of the sonic boom N-wave by controlling the nozzle plume interaction with the nozzle boat tail shock structure. This work was extended to study the impact of integrating a high aspect ratio exhaust nozzle or long slot nozzle on the trailing edge of a supersonic wing. The nozzle is operated in a highly under-expanded condition, creating a large exhaust plume and a shock at the trailing edge of the wing. This shock interacts with and suppresses the expansion wave caused by the wing, a major contributor to the sonic boom signature. The goal was to reduce the near field pressures caused by the expansion using a slot nozzle located at the wing trailing edge. Results from CFD analysis on a simulated wing cross-section and a slot nozzle indicate potential reductions in sonic boom signature compared to a baseline wing with no propulsion or trailing edge exhaust. Future studies could investigate if this effect could be useful on a supersonic aircraft for main propulsion, auxiliary propulsion, or flow control.

  9. Waveforms and Sonic Boom Perception and Response (WSPR): Low-Boom Community Response Program Pilot Test Design, Execution, and Analysis

    Science.gov (United States)

    Page, Juliet A.; Hodgdon, Kathleen K.; Krecker, Peg; Cowart, Robbie; Hobbs, Chris; Wilmer, Clif; Koening, Carrie; Holmes, Theresa; Gaugler, Trent; Shumway, Durland L.; hide

    2014-01-01

    The Waveforms and Sonic boom Perception and Response (WSPR) Program was designed to test and demonstrate the applicability and effectiveness of techniques to gather data relating human subjective response to multiple low-amplitude sonic booms. It was in essence a practice session for future wider scale testing on naive communities, using a purpose built low-boom demonstrator aircraft. The low-boom community response pilot experiment was conducted in California in November 2011. The WSPR team acquired sufficient data to assess and evaluate the effectiveness of the various physical and psychological data gathering techniques and analysis methods.

  10. Simulated sonic booms and sleep : effects of repeated booms of 1.0 psf.

    Science.gov (United States)

    1972-12-01

    Eight male subjects in each of three age groups (21-26, 40-45, 60-72 years) slept in pairs in the CAMI sonic boom simulation facility for 21 consecutive nights. The first five nights were used to acclimate the subjects (nights 1 and 2) and to obtain ...

  11. Swarm Deployable Boom Assembly (DBA) Development of a Deployable Magnetometer Boom for the Swarm Spacecraft

    Science.gov (United States)

    McMahon, Paul; Jung, Hans-Juergen; Edwards, Jeff

    2013-09-01

    The Swarm programme consists of 3 magnetically clean satellites flying in close formation designed to measure the Earth's magnetic field using 2 Magnetometers mounted on a 4.3m long deployable boom.Deployment is initiated by releasing 3 HDRMs, once released the boom oscillates back and forth on a pair of pivots, similar to a restaurant kitchen door hinge, for around 120 seconds before coming to rest on 3 kinematic mounts which are used to provide an accurate reference location in the deployed position. Motion of the boom is damped through a combination of friction, spring hysteresis and flexing of the 120+ cables crossing the hinge. Considerable development work and accurate numerical modelling of the hinge motion was required to predict performance across a wide temperature range and ensure that during the 1st overshoot the boom did not damage itself, the harness or the spacecraft.Due to the magnetic cleanliness requirements of the spacecraft no magnetic materials could be used in the design of the hardware.

  12. Bonding and Analysis of Composite TRAC Booms for NASA Science Missions, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A new deployable spacecraft boom technology called the Triangular Rollable And Collapsible Boom (TRACTM-Boom) has been invented by the Air Force Research Laboratory...

  13. Bonding and Analysis of Composite TRAC Booms for NASA Science Missions, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — A new deployable spacecraft boom technology called the Triangular Rollable And Collapsible Boom (TRACTM Boom), invented by the Air Force Research Laboratory and...

  14. Indoor Sonic Boom Reproduction Using ANC

    OpenAIRE

    Epain, Nicolas; Friot, Emmanuel; Rabau, Guy

    2005-01-01

    The European programs for development of supersonic air-flights involve new studies on the human perception of sonic boom. Because this noise includes high-level components at very low-frequency, the usual psycho-acoustic tests with headphones are not relevant; instead, the original sound-field can be reproduced with many loudspeakers in a small room, but the loudspeakers must be controlled for an accurate reproduction, both in time and space, in an area large enough to enclose a listener's h...

  15. El fideicomiso y el boom inmobiliario argentino

    OpenAIRE

    Francisco María Pertierra Cánepa; Mariano Pantanetti

    2011-01-01

    El presente trabajo tiene como objetivo investigar las diferentes alternativas que se ofrecen en el mercado de los denominados “fideicomisos inmobiliarios”1 para desarrollar un estudio detallado que permita identificar y evaluar como se está aplicando, y determinar el impacto que tuvo el instrumento en relación al boom de la actividad durante los últimos años. A través del análisis de las distintas alternativas comerciales de los proyectos inmobiliarios con fideicomisos podremos esclarecer si...

  16. The Effect of Sonic Booms on Earthquake Warning Systems

    Science.gov (United States)

    Wurman, Gilead; Haering, Edward A, Jr.; Price, Michael J.

    2011-01-01

    Several aerospace companies are designing quiet supersonic business jets for service over the United States. These aircraft have the potential to increase the occurrence of mild sonic booms across the country. This leads to interest among earthquake warning (EQW) developers and the general seismological community in characterizing the effect of sonic booms on seismic sensors in the field, their potential impact on EQW systems, and means of discriminating their signatures from those of earthquakes. The SonicBREWS project (Sonic Boom Resistant Earthquake Warning Systems) is a collaborative effort between Seismic Warning Systems, Inc. (SWS) and NASA Dryden Flight Research Center. This project aims to evaluate the effects of sonic booms on EQW sensors. The study consists of exposing high-sample-rate (1000 sps) triaxial accelerometers to sonic booms with overpressures ranging from 10 to 600 Pa in the free field and the built environment. The accelerometers record the coupling of the sonic boom to the ground and surrounding structures, while microphones record the acoustic wave above ground near the sensor. Sonic booms are broadband signals with more high-frequency content than earthquakes. Even a 1000 sps accelerometer will produce a significantly aliased record. Thus the observed peak ground velocity is strongly dependent on the sampling rate, and increases as the sampling rate is reduced. At 1000 sps we observe ground velocities that exceed those of P-waves from ML 3 earthquakes at local distances, suggesting that sonic booms are not negligible for EQW applications. We present the results of several experiments conducted under SonicBREWS showing the effects of typical-case low amplitude sonic booms and worst-case high amplitude booms. We show the effects of various sensor placements and sensor array geometries. Finally, we suggest possible avenues for discriminating sonic booms from earthquakes for the purposes of EQW.

  17. Potential for Sonic Boom Reduction of the Boeing HSCT

    Science.gov (United States)

    Haglund, George T.

    1999-01-01

    The HSR sonic boom technology program includes a goal of reducing the objectionable aspects of sonic boom. Earlier HSCT sonic boom studies considered achieving significant sonic boom reduction by the use of arrow-wing planforms and detailed shaping of the airplane to produce shaped waveforms (non N-waves) at the ground. While these design efforts were largely successful, the added risk and cost of the airplanes were judged to be unacceptable. The objective of the current work is to explore smaller configuration refinements that could lead to reduced sonic boom impact, within design and operational constraints. A somewhat modest target of 10% reduction in sonic boom maximum overpressure was selected to minimize the effect on the configuration performance. This work was a joint NASA/Industry effort, utilizing the respective strengths of team members at Boeing, NASA Langley, and NASA Ames. The approach used was to first explore a wide range of modifications and airplane characteristics for their effects on sonic boom and drag, using classical Modified Linear Theory (MLT) methods. CFD methods were then used to verify promising, modifications and to analyze modifications for which the MLT methods were not appropriate. The tea m produced a list of configuration changes with their effects on sonic boom and, in some cases, an estimate of the drag penalty. The most promising modifications were applied to produce a boom-softened derivative of the baseline Boeing High Speed Civil Transport (HSCT) configuration. This boom-softened configuration was analyzed in detail for the reduce sonic boom impact and also for the effect of the configuration modifications on drag, weight, and overall performance relative to the baseline.

  18. Low-Boom and Low-Drag Optimization of the Twin Engine Version of Silent Supersonic Business Jet

    Science.gov (United States)

    Sato, Koma; Kumano, Takayasu; Yonezawa, Masahito; Yamashita, Hiroshi; Jeong, Shinkyu; Obayashi, Shigeru

    Multi-Objective Optimization has been applied to a design problem of the twin engine concept for Silent Supersonic Business Jet (SSBJ). This problem aims to find main wing, body, tail wing and engine nacelle configurations, which can minimize both sonic boom and drag in a supersonic cruising flight. The multi-objective genetic algorithm (MOGA) coupled with the Kriging model has been used to globally and effectively search for optimal design candidates in the multi-objective problem. The drag and the sonic boom have been evaluated by the computational fluid dynamics (CFD) simulation and the waveform parameter method. As a result, the present optimization has successfully obtained low-boom and low-drag design candidates, which are better than the baseline design by more than 40% regarding each performance. Moreover, the structure of design space has been visualized by the self-organizing map (SOM).

  19. Field measurements of sonic boom penetration into the ocean

    Science.gov (United States)

    Sohn; Vernon; Hildebrand; Webb

    2000-06-01

    Six sonic booms, generated by F-4 aircraft under steady flight at a range of altitudes (610-6100 m) and Mach numbers (1.07-1.26), were measured just above the air/sea interface, and at five depths in the water column. The measurements were made with a vertical hydrophone array suspended from a small spar buoy at the sea surface, and telemetered to a nearby research vessel. The sonic boom pressure amplitude decays exponentially with depth, and the signal fades into the ambient noise field by 30-50 m, depending on the strength of the boom at the sea surface. Low-frequency components of the boom waveform penetrate significantly deeper than high frequencies. Frequencies greater than 20 Hz are difficult to observe at depths greater than about 10 m. Underwater sonic boom pressure measurements exhibit excellent agreement with predictions from analytical theory, despite the assumption of a flat air/sea interface. Significant scattering of the sonic boom signal by the rough ocean surface is not detected. Real ocean conditions appear to exert a negligible effect on the penetration of sonic booms into the ocean unless steady vehicle speeds exceed Mach 3, when the boom incidence angle is sufficient to cause scattering on realistic open ocean surfaces.

  20. Thermal Deformation of Very Slender Triangular Rollable and Collapsible Booms

    Science.gov (United States)

    Stohlman, Olive R.; Loper, Erik R.

    2016-01-01

    Metallic triangular rollable and collapsible (TRAC) booms have deployed two Cubesat-based solar sails in low Earth orbit, making TRAC booms the most popular solar sail deployment method in practice. This paper presents some concerns and solutions surrounding the behavior of these booms in the space thermal environment. A 3.5-cm-tall, 4-meter-long TRAC boom of Elgiloy cobalt alloy, when exposed to direct sunlight in a 1 AU deep space environment, has a predicted tip motion of as much as 0.5 meters. Such large thermal deflections could generate unacceptable distortions in the shape of a supported solar sail, making attitude control of the solar sail spacecraft difficult or impossible. As a possible means of mitigating this issue, the thermal distortion behaviors of three alternative material TRAC booms are investigated and compared with the uncoated Elgiloy baseline boom. A tenfold decrease in induced curvature is shown to be possible relative to the baseline boom. Potential thermal distortions of the LightSail-A solar sail TRAC booms are also examined and compared, although inconclusively, with available on-orbit camera imagery.

  1. Subjective loudness of "minimized" sonic boom waveforms.

    Science.gov (United States)

    Niedzwiecki, A; Ribner, H S

    1978-12-01

    For very long supersonic aircraft the "midfield" sonic boom signature may not have evolved fully into an N wave at ground level. Thus in current boom minimization techniques the shape of the aircraft may be tailored to optimize this midfield wave form for reduced subjective loudness. The present investigation tests a family of "flat-top" waveforms cited by Darden: all but one have a front shock height (deltapSH) less than the peak amplitude (deltapMAX). For equal subjective loudness, "flat top" vs N wave (peak overpressure deltapN), the peak amplitude of the "flat top" signature was found to be substantially higher than that of the N wave; thus for equal peak amplitude the "flat-top" signature was quieter. The results for equal loudness were well fitted by an emperical law deltapSH + 0.11deltapMAX = deltapN; the equivalence shows how the front shock amplitude (deltapSH) dominates the loudness. All this was found compatible with predictions by the method of Johnson and Robinson.

  2. Effects of Polyacrylamide in Controlling of Splash Erosion from a Soil induced Freeze-Thaw Cycle

    Directory of Open Access Journals (Sweden)

    S.H.R. Sadeghi

    2016-09-01

    Full Text Available Introduction: The capability of a soil to resist erosion depends on soil-particle size and distribution, soil structure and structural stability, soil permeability, water content, organic matter content, and mineral and chemical constituents. Among many affecting factors on aforesaid characteristics, the freezing-thawing processes may considerably affects. Freeze–thaw fluctuation is a natural phenomenon that is frequently encountered by soils in the higher latitude and altitude regions in late autumn and early spring. Effects of freezing and freezing-thawing phenomena on soil erosion and sediment yield are important. Nevertheless, soil conservation under these phenomena by using different methods as well as soil amendments has not been yet considered. Surface application of anionic polyacrylamide (PAM in solution has been found to be very effective in decreasing seal formation, runoff, and erosion.PAM stabilizes soil structure due to the ability of the polymer chains to adsorb onto clay particles and bridge them together forming stable domains. This adsorption can be a result of interactions between the negatively-charged functional groups of the PAM molecules and the positively-charged edges of clay minerals, orexchangeable polycations (mainly Ca2+ acting as ‘bridges’ between the negative charges of the PAM's functional groups and the negatively- charged planar surfaces of the clay. The PAM is adsorbed on the external surfaces of the aggregates and binds soil particles far apart together, thereby were shorter and evidently less effective in enhancing increasing their resistance to splash by raindrop impact and detachment by runoff. A lot of research work focused on freezing effects in soils on aggregation or increase aggregate stability and emphasis corresponding effects. But the effects of application of soil amendments on soil induced freeze and thaw cycle have not been studied yet. Materials and Methods: The present study evaluated the

  3. Investigation and prevention of droplet splashing during operation of a sodium free jet flow

    Energy Technology Data Exchange (ETDEWEB)

    Stoppel, L.; Gordeev, S.; Wetzel, T.; Fellmoser, F.; Daubner, M. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). KALLA Lab.; Stieglitz, R. [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (DE). Inst. for Neutron Physics and Reactor Technology (INR)

    2010-05-15

    Many accelerator application concepts consider liquid metal as a windowless target, at which the particle beam does directly hit the liquid. One of such concepts is studied in the European project ''DIRAC-Secondary beams - Design Study''. This project is focused on the preliminary research work for construction of a new international particle accelerator - Facility for Antiproton and Ion Research (FAIR) in Darmstadt. The planned accelerator is aimed to work with high-energy heavy-ions, such as U{sup 238}. One of the key elements of the FAIR facility is a liquid-metal-target, made in the form of a rectangular shaped Lithium jet aligned with the gravity vector. In the course of preliminary investigations the theoretical and practical conditions for a stable liquid-metal-jet conforming to the FAIR-requirements have been studied in the Karlsruhe Liquid Metal Laboratory (KALLA) sodium facility. The acquired scientific and technological results can be transferred to liquid-metal targets in nuclear applications, for example, the IFMIF-Target for the study of fusion reactor materials and the Myrrah/XT-ADS target. The main goals of the KALLA-part of the project were to design and build a facility for experimental research on hydrodynamic phenomena of the free surface liquid metal flow as well as to look at technological problems influencing the hydrodynamic stability of such flows. One of such problems emerged already during the startup of the facility: Splashing of liquid metal drops in the vacuum volume of the target box. As a result of such splashing process, liquid metal droplets are accumulated on various internal constructional elements of the target box, for example, on the inspection windows. This effect prohibits long term operation with the facility. The present paper describes the methods used to reduce the splashing to a minimum. (orig.)

  4. A unified approach to an augmented Burgers equation for the propagation of sonic booms.

    Science.gov (United States)

    Yamamoto, Masafumi; Hashimoto, Atsushi; Aoyama, Takashi; Sakai, Takeharu

    2015-04-01

    Nonlinear propagation through a relaxing atmosphere of pressure disturbances extracted from a computational fluid dynamics (CFD) solution of the flow around a supersonic aircraft is simulated using an augmented Burgers equation. The effects of nonlinearity, geometrical spreading, atmospheric inhomogeneity, thermoviscous attenuation, and molecular vibration relaxation are taken into account. The augmented Burgers equation used for sonic boom propagation calculations is often solved by the operator splitting method, but numerical difficulties arise with this approach when dissipation is not effective. By re-examining the solution algorithms for the augmented Burgers equation, a stable method for handling the relaxation effect has been developed. This approach can handle the Burgers equation in a unified manner without operator splitting and, therefore, the resulting scheme is twice as fast as the original one. The approach is validated by comparing it with an analytical solution and a detailed CFD of dispersed plane wave propagation. In addition, a rise time prediction of low-boom supersonic aircraft is demonstrated.

  5. Baby boom generation at the retirement onset

    Directory of Open Access Journals (Sweden)

    Stojilković Jelena

    2010-01-01

    Full Text Available Sudden increase in the number of live births after the Second World War due to an increase in fertility rates has led to the formation of cohorts with specific characteristics or baby boom generation. This generation is unique in the history of the demographic phenomenon that has affected and affects the functioning of many segments of society. The aim of this paper is to assess structure of baby boomers who are few years away from retirement, using demographic data. Impact of baby boomer age structure of current and future retirees is described with a graphical display of current and projected age pyramid of baby boomers. Demographic pattern that women live longer than men is evident in the projected pyramid. In addition, the number of baby boomers will lead to a "younger" old population. The imbalance in the number of men and women pensioners, as well as older cohorts of women and female baby boomers was analyzed. As a result, an increasing trend of women's age pensioners who are members of the baby boom generation was clearly observed, which is opposite to the older cohort of women who often were family pensioners. Different circumstances and conditions in which female boomers lived and worked will form a new "pension model" because they will gain their benefits as well as men, for the first time in significant number, unlike their mothers, which gained the right to retire after they become widows. Number of women age pensioners is getting greater comparing to men, as the result of changes in the economic activities of women in the last half of the 20th century. When baby boomers retire and exit the working population, this will create a vacuum, because the numerically smaller generations will enter working population, while the sudden and very shortly, the number of population older than 60 or 65 will increase, most of them will likely to acquire the right to a pension. It is undeniable that baby boomers had impact on demographic structure

  6. Impact induced splash and spill in a quasi-confided granular medium

    Science.gov (United States)

    Ogale, S. B.

    2005-03-01

    Dissipation of the energy of impact in a granular medium and its effects has been a subject of considerable scientific for quite some time. In this work we have explored and analyzed the splash and spill effects caused by the impact of a ball dropped from a height into a granular medium in a open container. Three different granular media, namely rice, mustard seeds, and cream of wheat were used. The amount of spilled-over granular matter was measured as a function of the ball-drop height. Digital pictures of the splash process were also recorded. The quantity of spilled granular matter varies linearly with the impact energy. However additional step like structures are also noted. Specifically, a distinct and large jump is seen in the spilled quantity at a specific impact energy in the case of mustard seeds, which also exhibit obvious charging effects and repulsion. Although the parameters such as mass per grain and packing density for the case of mustard seeds are intermediate between those for rice and cream of wheat, the spill quantity for comparable impact energy is considerably higher. These data will be presented and discussed.

  7. Impact-induced splash and spill in a quasi-confined granular medium

    Science.gov (United States)

    Ogale, S. B.; Shinde, S. R.; Karve, P. A.; Ogale, Abhijit S.; Kulkarni, A.; Athawale, A.; Phadke, A.; Thakurdas, R.

    2006-05-01

    The splash and spill effects caused by the impact of a ball dropped from a height into a granular medium held in a small open container are examined. Different granular media, namely rice, mustard seeds, cream of wheat and plastic beads are used. The quantity of spilled-over granular matter ( W, grams) is measured as a function of the ball-drop height and compared for different cases. Digital pictures of the splash process are also recorded. The quantity W is seen to vary approximately linearly with the energy of impact. Interestingly, a distinct upward jump is seen in the spilled quantity at specific impact energy in the case of mustard seeds, which have spherical shape and also exhibit some charging effects. Similar jump was also confirmed for the case of plastic beads with broadly similar properties. Although the parameters such as mass per grain and packing density for the case of mustard seeds are intermediate between those for rice and cream of wheat, the spill quantity for comparable impact energy is considerably higher in the former case. The possible reasons for this non-monotonicity of behavior are discussed in terms of the differences in grain shapes and properties. Experiments are also performed using plastic beads of the same type but with four different sizes to explore the dependence of spilled quantity on bead size. The container size dependence is also examined for various bead types. Interesting systematics are seen, which are discussed qualitatively.

  8. Experimental and Computational Sonic Boom Assessment of Boeing N+2 Low Boom Models

    Science.gov (United States)

    Durston, Donald A.; Elmiligui, Alaa; Cliff, Susan E.; Winski, Courtney S.; Carter, Melissa B.; Walker, Eric L.

    2015-01-01

    Near-field pressure signatures were measured and computational predictions made for several sonic boom models representing Boeing's Quiet Experimental Validation Concept (QEVC) supersonic transport, as well as three axisymmetric calibration models. Boeing developed the QEVC under a NASA Research Announcement (NRA) contract for Experimental Systems Validations for N+2 Supersonic Commercial Transport Aircraft, which was led by the NASA High Speed Project under the Fundamental Aeronautics Program. The concept was designed to address environmental and performance goals given in the NRA, specifically for low sonic boom loudness levels and high cruise efficiency, for an aircraft anticipated to enter service in the 2020 timeframe. Wind tunnel tests were conducted on the aircraft and calibration models during Phases I and II of the NRA contract from 2011 to 2013 in the NASA Ames 9- by 7-Foot and NASA Glenn 8- by 6-Foot Supersonic Wind Tunnels. Sonic boom pressure signatures were acquired primarily at Mach 1.6 and 1.8, and force and moment data were acquired from Mach 0.8 to 1.8. The sonic boom test data were obtained using a 2-in. flat-top pressure rail and a 14-in. round-top tapered "reflection factor 1" (RF1) pressure rail. Both rails capture an entire pressure signature in one data point, and successive signatures at varying positions along or above the rail were used to improve data quality through spatial averaging. The sonic boom data obtained by the rails were validated with high-fidelity numerical simulations of off-body pressures using the CFD codes USM3D, Cart3D, and OVERFLOW. The test results from the RF1 rail showed good agreement between the computational and experimental data when a variety of testing techniques including spatial averaging of a series of pressure signatures were employed, however, reflections off the 2-in. flat-top rail caused distortions in the signatures that did not agree with the CFD predictions. The 9 x 7 and 8 x 6 wind tunnels generally

  9. Sonic Boom Minimization Efforts on Boeing HSCT Baseline

    Science.gov (United States)

    Cheung, Samson H.; Fouladi, Kamran; Haglund, George; Tu, Eugene

    1999-01-01

    A team was formed to tackle the sonic boom softening issues of the current Boeing HSCT design. The team consisted of personnel from NASA Ames, NASA Langley, and Boeing company. The work described in this paper was done when the first author was at NASA Ames Research Center. This paper presents the sonic boom softening work on two Boeing High Speed Civil Transport (HSCT) baseline configurations, Reference-H and Boeing-1122. This presentation can be divided into two parts: parametric studies and sonic boom minimization by CFD optimization routines.

  10. Adjoint-Based Mesh Adaptation for the Sonic Boom Signature Loudness

    Science.gov (United States)

    Rallabhandi, Sriram K.; Park, Michael A.

    2017-01-01

    The mesh adaptation functionality of FUN3D is utilized to obtain a mesh optimized to calculate sonic boom ground signature loudness. During this process, the coupling between the discrete-adjoints of the computational fluid dynamics tool FUN3D and the atmospheric propagation tool sBOOM is exploited to form the error estimate. This new mesh adaptation methodology will allow generation of suitable meshes adapted to reduce the estimated errors in the ground loudness, which is an optimization metric employed in supersonic aircraft design. This new output-based adaptation could allow new insights into meshing for sonic boom analysis and design, and complements existing output-based adaptation techniques such as adaptation to reduce estimated errors in off-body pressure functional. This effort could also have implications for other coupled multidisciplinary adjoint capabilities (e.g., aeroelasticity) as well as inclusion of propagation specific parameters such as prevailing winds or non-standard atmospheric conditions. Results are discussed in the context of existing methods and appropriate conclusions are drawn as to the efficacy and efficiency of the developed capability.

  11. Detection and assessment of secondary sonic booms in New England

    Science.gov (United States)

    1980-05-01

    This report documents the results of a secondary sonic boom detection and assessment program conducted by the U.S. Dept. of Transportation, Transportation Systems Center in New England during the summer of 1979. Measurements of both acoustic and infr...

  12. Construction Boom Seen on Campuses over Next 5 Years.

    Science.gov (United States)

    Evangelauf, Jean

    1987-01-01

    Campus construction is projected to boom as colleges and universities catch up on deferred maintenance and replace outdated classrooms and laboratories. Severe problems identified include roofs, heating systems, asbestos removal, and electical systems. (LB)

  13. High Performance TRAC Boom for Solar Sails, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to NASA's need for compact, low-cost deployable solar sail booms for CubeSats, Roccor proposes to develop a high performance composite TRAC (TRAC HP)...

  14. Elastic Deployable Composite Tubular Roll-Out Boom, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — DSS's innovative Elastic Deployable Composite Tubular Roll-Out Boom will provide revolutionary performance when compared to conventional state-of-the-art...

  15. Elastic Deployable Composite Tubular Roll-Out Boom, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Deployable Space Systems (DSS) has developed an affordable and ultra-lightweight elastically self-deployable Roll-Out Boom technology that provides affordability and...

  16. Confidence Intervals for Laboratory Sonic Boom Annoyance Tests

    Science.gov (United States)

    Rathsam, Jonathan; Christian, Andrew

    2016-01-01

    Commercial supersonic flight is currently forbidden over land because sonic booms have historically caused unacceptable annoyance levels in overflown communities. NASA is providing data and expertise to noise regulators as they consider relaxing the ban for future quiet supersonic aircraft. One deliverable NASA will provide is a predictive model for indoor annoyance to aid in setting an acceptable quiet sonic boom threshold. A laboratory study was conducted to determine how indoor vibrations caused by sonic booms affect annoyance judgments. The test method required finding the point of subjective equality (PSE) between sonic boom signals that cause vibrations and signals not causing vibrations played at various amplitudes. This presentation focuses on a few statistical techniques for estimating the interval around the PSE. The techniques examined are the Delta Method, Parametric and Nonparametric Bootstrapping, and Bayesian Posterior Estimation.

  17. Rapidly Extending And Contracting Tubular (REACT) Boom System Development

    Data.gov (United States)

    National Aeronautics and Space Administration — This project aims to create a prototype retractable, reel stored, tubular boom system with the capability to hold a magnetically sensitive science instrument or...

  18. Aerodynamical and sonic boom optimization of a supersonic aircraft

    OpenAIRE

    Vázquez, M.; Dervieux, Alain; Koobus, B.

    2002-01-01

    Sonic Boom Reduction will be an issue of utmost importance in future supersonic carriers, due to strong regulations on acoustic nuisance. The present work introduces a technique for optimizing the aerodynamical performan- ce and the sonic boom production, through optimal shape design. Based in a so-called CAD-free parametrization method, which relies on the discretized shape by working in a parameter space determined by the skin nodes physical location, this methodology introduces several dis...

  19. AFRL/NASA Shaped Sonic Boom Experiment Flight Test Program. Delivery Order 0021: Origins and Overview of the Shaped Sonic Boom Demonstration Program

    National Research Council Canada - National Science Library

    Pawlowski, Joseph W; Graham, David H; Boccadoro, Charles H; Coen, Peter G; Maglieri, Domenic J

    2005-01-01

    The goal of the DARPA Shaped Sonic Boom Demonstration (SSBD) Program was to demonstrate for the first time in flight that sonic booms can be substantially reduced by incorporating specialized aircraft shaping techniques...

  20. Behavioral, autonomic, and subjective reactions to low- and moderate-level simulated sonic booms : a report of two experiments and a general evaluation of sonic boom startle effects.

    Science.gov (United States)

    1974-09-01

    Two separate studies are reported. The first attempted to determine a sonic boom exposure level below which startle reactions would not occur. Subjects were exposed indoors to six simulated sonic booms having various outside overpressures. In the sec...

  1. Partitioning washoff of manure-borne fecal indicators (Escherichia coli and stanols) into splash and hydraulic components: field rainfall simulations in a tropical agro-ecosystem.

    Science.gov (United States)

    Ribolzi, Olivier; Rochelle-Newall, Emma J.; Janeau, Jean-Louis; Viguier, Marion; Jardé, Emilie; Latsachack, Keooudone; Henri-Des-Tureaux, Thierry; Thammahacksac, Chanthamousone; Mugler, Claude; Valentin, Christian; Sengtaheuanghoung, Oloth

    2017-04-01

    Overland flow from manured fields and pastures is known to be an important mechanism by which organisms of faecal origin are transferred to streams in rural watersheds. In the tropical montane areas of South-East Asia, recent changes in land use have induced increased runoff, soil erosion, in-stream suspended sediment loads resulting in increased microbial pathogen dissemination and contamination of stream waters. The majority of enteric and environmental bacteria in aquatic systems are associated with particles such as sediments which can strongly influence their survival and transport characteristics. Escherichia coli (E. coli) has emerged as one of the most appropriate microbial indicators of faecal contamination of natural waters, with the presence of E. coli indicating that faecal contamination is present. In association with E. coli, faecal stanols can also be used as microbial source tracking tool for the identification of the origin of the faecal contamination (e.g. livestock, human, etc). Field rain simulations were used to examine how E.coli and stanols are exported from the surface of upland, agricultural soils during overland flow events. The objectives were to characterize the loss dynamics of these indicators from agricultural soils contaminated with livestock waste, and to partition total detachment into the splash and hydraulic components. Nine 1m2 microplots were divided in triplicated treatment groups: (a) controls with no amendments, (b) amended with pig manure or (c) poultry manure. Each plot was divided into two 0.5m2 rectangular subplots. For each simulation, one subplot was designated as a rain splash treatment; the other was covered with 2-mm grid size wire screen 10 cm above the soil surface to break the raindrops into fine droplets, thus drastically reducing their kinetic energy. E. coli concentrations in overland flow were estimated for both the attached and free living fractions and stanols were measured on the particulate matter washed

  2. USM3D Simulations for Second Sonic Boom Workshop

    Science.gov (United States)

    Elmiligui, Alaa; Carter, Melissa B.; Nayani, Sudheer N.; Cliff, Susan; Pearl, Jason M.

    2017-01-01

    The NASA Tetrahedral Unstructured Software System with the USM3D flow solver was used to compute test cases for the Second AIAA Sonic Boom Prediction Workshop. The intent of this report is to document the USM3D results for SBPW2 test cases. The test cases included an axisymmetric equivalent area body, a JAXA wing body, a NASA low boom supersonic configuration modeled with flow through nacelles and engine boundary conditions. All simulations were conducted for a free stream Mach number of 1.6, zero degrees angle of attack, and a Reynolds number of 5.7 million per meter. Simulations were conducted on tetrahedral grids provided by the workshop committee, as well as a family of grids generated by an in-house approach for sonic boom analyses known as BoomGrid using current best practices. The near-field pressure signatures were extracted and propagated to the ground with the atmospheric propagation code, sBOOM. The USM3D near-field pressure signatures, corresponding sBOOM ground signatures, and loudness levels on the ground are compared with mean values from other workshop participants.

  3. Vibration Penalty Estimates for Indoor Annoyance Caused by Sonic Boom

    Science.gov (United States)

    Rathsam, Jonathan; Klos, Jacob

    2016-01-01

    Commercial supersonic flight is currently forbidden over land because sonic booms have historically caused unacceptable annoyance levels in overflown communities. NASA is providing data and expertise to noise regulators as they consider relaxing the ban for future quiet supersonic aircraft. One key objective is a predictive model for indoor annoyance based on factors such as noise and indoor vibration levels. The current study quantified the increment in indoor sonic boom annoyance when sonic booms can be felt directly through structural vibrations in addition to being heard. A shaker mounted below each chair in the sonic boom simulator emulated vibrations transmitting through the structure to that chair. The vibration amplitudes were determined from numeric models of a large range of residential structures excited by the same sonic boom waveforms used in the experiment. The analysis yielded vibration penalties, which are the increments in sound level needed to increase annoyance as much as the vibration does. For sonic booms at acoustic levels from 75 to 84 dB Perceived Level, vibration signals with lower amplitudes (+1 sigma) yielded penalties from 0 to 5 dB, and vibration signals with higher amplitudes (+3 sigma) yielded penalties from 6 to 10 dB.

  4. Corrosion Behavior of Low-C Medium-Mn Steel in Simulated Marine Immersion and Splash Zone Environment

    Science.gov (United States)

    Zhang, Dazheng; Gao, Xiuhua; Su, Guanqiao; Du, Linxiu; Liu, Zhenguang; Hu, Jun

    2017-05-01

    The corrosion behavior of low-C medium-Mn steel in simulated marine immersion and splash zone environment was studied by static immersion corrosion experiment and wet-dry cyclic corrosion experiment, respectively. Corrosion rate, corrosion products, surface morphology, cross-sectional morphology, elemental distribution, potentiodynamic polarization curves and electrochemical impedance spectra were used to elucidate the corrosion behavior of low-C medium-Mn steel. The results show that corrosion rate in immersion zone is much less than that in splash zone owing to its relatively mild environment. Manganese compounds are detected in the corrosion products and only appeared in splash zone environment, which can deteriorate the protective effect of rust layer. With the extension of exposure time, corrosion products are gradually transformed into dense and thick corrosion rust from the loose and porous one in these two environments. But in splash zone environment, alloying elements of Mn appear significant enrichment in the rust layer, which decrease the corrosion resistance of the steel.

  5. LHC Beam Splash seen by the ATLAS detector - 5 Apr 2015 - Run 260272 - LB 240 - event 5879

    CERN Multimedia

    ATLAS EXPERIMENT

    2015-01-01

    Event display of first collimator "splash" event seen by the ATLAS experiment in LHC Run-2 , on Sunday April the 5th : event 5879, run 260272. The collimator position is 140m in front of the ATLAS interaction point. The spray of particles enters ATLAS from the right hand side of the picture.

  6. Study of a 30-M Boom For Solar Sail-Craft: Model Extendibility and Control Strategy

    Science.gov (United States)

    Keel, Leehyun

    2005-01-01

    Space travel propelled by solar sails is motivated by the fact that the momentum exchange that occurs when photons are reflected and/or absorbed by a large solar sail generates a small but constant acceleration. This acceleration can induce a constant thrust in very large sails that is sufficient to maintain a polar observing satellite in a constant position relative to the Sun or Earth. For long distance propulsion, square sails (with side length greater than 150 meters) can reach Jupiter in two years and Pluto in less than ten years. Converting such design concepts to real-world systems will require accurate analytical models and model parameters. This requires extensive structural dynamics tests. However, the low mass and high flexibility of large and light weight structures such as solar sails makes them unsuitable for ground testing. As a result, validating analytical models is an extremely difficult problem. On the other hand, a fundamental question can be asked. That is whether an analytical model that represents a small-scale version of a solar-sail boom can be extended to much larger versions of the same boom. To answer this question, we considered a long deployable boom that will be used to support the solar sails of the sail-craft. The length of fully deployed booms of the actual solar sail-craft will exceed 100 meters. However, the test-bed we used in our study is a 30 meter retractable boom at MSFC. We first develop analytical models based on Lagrange s equations and the standard Euler-Bernoulli beam. Then the response of the models will be compared with test data of the 30 meter boom at various deployed lengths. For this stage of study, our analysis was limited to experimental data obtained at 12ft and 18ft deployment lengths. The comparison results are positive but speculative. To observe properly validate the analytic model, experiments at longer deployment lengths, up to the full 30 meter, have been requested. We expect the study to answer the

  7. Application of X-ray computed microtomography to soil craters formed by raindrop splash

    Science.gov (United States)

    Beczek, Michał; Ryżak, Magdalena; Lamorski, Krzysztof; Sochan, Agata; Mazur, Rafał; Bieganowski, Andrzej

    2018-02-01

    The creation of craters on the soil surface is part of splash erosion. Due to the small size of these craters, they are difficult to study. The main aim of this paper was to test X-ray computed microtomography to investigate craters formed by raindrop impacts. Measurements were made on soil samples moistened to three different levels corresponding with soil water potentials of 0.1, 3.16 and 16 kPa. Using images obtained by X-ray microtomography, geometric parameters of the craters were recorded and analysed. X-ray computed microtomography proved to be a useful and efficient tool for the investigation of craters formed on the soil surface after the impact of water drops. The parameters of the craters changed with the energy of the water drops and were dependent on the initial moisture content of the soil. Crater depth is more dependent on the increased energy of the water drop than crater diameter.

  8. Cultivar architecture modulates spore dispersal by rain splash: A new perspective to reduce disease progression in cultivar mixtures.

    Directory of Open Access Journals (Sweden)

    Tiphaine Vidal

    Full Text Available Cultivar mixtures can be used to improve the sustainability of disease management within farming systems by growing cultivars that differ in their disease resistance level in the same field. The impact of canopy aerial architecture on rain-splash dispersal could amplify disease reduction within mixtures. We designed a controlled conditions experiment to study single splash-dispersal events and their consequences for disease. We quantified this impact through the spore interception capacities of the component cultivars of a mixture. Two wheat cultivars, differing in their aerial architecture (mainly leaf area density and resistance to Septoria tritici blotch, were used to constitute pure stands and mixtures with 75% of resistant plants that accounted for 80% of the canopy leaf area. Canopies composed of 3 rows of plants were exposed to standardized spore fluxes produced by splashing calibrated rain drops on a linear source of inoculum. Disease propagation was measured through spore fluxes and several disease indicators. Leaf susceptibility was higher for upper than for lower leaves. Dense canopies intercepted more spores and mainly limited horizontal spore transfer to the first two rows. The presence of the resistant and dense cultivar made the mixed canopy denser than the susceptible pure stand. No disease symptoms were observed on susceptible plants of the second and third rows in the cultivar mixture, suggesting that the number of spores intercepted by these plants was too low to cause disease symptoms. Both lesion area and disease conditional severity were significantly reduced on susceptible plants within mixtures on the first row beside the inoculum source. Those reductions on one single-splash dispersal event, should be amplified after several cycle over the full epidemic season. Control of splash-dispersed diseases within mixtures could therefore be improved by a careful choice of cultivars taking into consideration both resistance and

  9. Boom and Bust Cycles in Saturn's Rings

    Science.gov (United States)

    Esposito, L. W.; Meinke, B. K.; Sremcevic, M.; Albers, N.

    2010-12-01

    Cassini UVIS occultation data show clumping in Saturn’s F ring and at the B ring outer edge, indicating aggregation and disaggregation at these locations perturbed by Mimas and Prometheus. Timescales range from hours to months. The maximum clumping lags the moon by roughly π in the forcing frame. This indicates a direct relation between the moon and the ring clumping. We propose that the collective behavior of the ring particles resembles a predator-prey system: the aggregate mean size is the prey, which feeds the velocity dispersion; conversely, increasing dispersion breaks up the aggregates. For realistic values of the parameters this creates a limit cycle behavior, as for the ecology of foxes and hares or the boom-bust economic cycle. Solving for the long-term behavior of this forced system gives a periodic response at the perturbing frequency, with a phase lag roughly consistent with the UVIS occultation measurements. We conclude that the agitation by the moons at both these locations in the F ring and at the B ring outer edge drives aggregation and disaggregation in the forcing frame. This agitation of the ring material allows fortuitous formation of solid objects from the temporary clumps, via stochastic processes like compaction, adhesion, sintering or reorganization that drives the denser parts of the aggregate to the center or ejects the lighter elements. These more persistent objects would then orbit at the Kepler rate. Such processes can create the equinox objects seen at the B ring edge and in the F ring, explain the ragged nature of those ring regions and allow for rare events to aggregate ring particles into solid objects, recycling the ring material and extending the ring lifetime.

  10. Effects of Fire on Soil Splash Erosion in Semi-steppe Rangelandof Karsanak Region,Chaharmahal and Bakhtiari

    Directory of Open Access Journals (Sweden)

    D. Baharlooi

    2016-02-01

    Full Text Available Introduction: The detachment process can be conceptually divided in two sub-processes included aggregate breakdown (Le Bissonnais, 1996 and movement initiation of breakdown products(Kinnell, 2005. soil detachment depends on raindrop size and mass(Elison, 1944; Bisal, 1960, drop velocity(Elison, 1944; Bisal, 1960, intensity rainfall (Ting et al, 2008, kinetic energy (Kinnell, 2003; Fernandez- Raga et al, 2010, runoff depth(Torri et al, 1987; Kinnell,1991 and 2005, crop covers(Bancy, 1994; Ghahremani et al, 2011, wind speed( Erpul et al, 2000 and experimental area (cup size (Leguedois et al, 2005; Luk, 1979; Torri and poesen, 1988. Many of studies have been conducted to evaluate the relationship between splash and slope (Bryan, 1979; Torri and Poesen, 1992; Wan et al, 1996.Torri and Poesen (1992 expressed that in steep slope the gravity force adds to the drop detaching force and decreases of soil resistance, consequently increases splash erosion rate with increasing slope. Soil splash erosion is also strongly influenced by soil properties including soil particles size distribution (Mazurak and Mosher, 1968; Legout et al, 2005; fan and li, 1993, soil shear strength(Cruse and Larson, 1977; Al-Durrah and Bradford,1981; Ekwue and ohi; 1990 , soil cohesion(Torri et al, 1987, soil organic matter content and aggregate size (Ekwue and Maiduguri, 1991; Qinjuan et al, 2008, soil aggregates stability(Qinjuan et al, 2008, surface crust (Qinjuan et al, 2008. Fire, play an important role in splash erosion. The absence of vegetation cover in disturbed lands accelerates splash erosion rates by as much as several folds compared to undisturbed sites (Lal, 2001; Thomaz and luiz, 2012.The detachment of soil particles by splash depends on several raindrop characteristics, including raindrop size and mass, drop velocity, kinetic energy, and water drop impact angle (Sharma et al., 1993; Singer and Le Bissonnais, 1998; Cruse et al., 2000, Bhattacharyya et al., 2010

  11. Stability of sonic boom metrics regarding signature distortions from atmospheric turbulence.

    Science.gov (United States)

    Doebler, William J; Sparrow, Victor W

    2017-06-01

    The degree of insensitivity to atmospheric turbulence was evaluated for five metrics (A-, B-, E-weighted sound exposure level, Stevens Mark VII Perceived Level, and NASA's Indoor Sonic Boom Annoyance Predictor) that correlate to human annoyance from sonic booms. Eight N-wave shaped sonic booms from NASA's FaINT experiment and five simulated "low-boom" sonic booms were turbulized by Locey's ten atmospheric filter functions. The B-weighted sound exposure level value changed the least due to the turbulence filters for twelve of thirteen booms. This makes it the most turbulence stable metric which may be useful for quiet supersonic aircraft certification.

  12. Facts and features of radionuclide migration in Boom Clay

    International Nuclear Information System (INIS)

    De Regge, P.; Henrion, P.; Monsecour, M.; Put, M.

    1988-01-01

    The evolution which took place during ten years of research on the behaviour of radionuclides in Boom Clay is described. Initially, the Boom Clay was regarded as a chemically inert exchanger and the radiochemical research aimed at determining the distribution of cations between the clay and some liquid phases. The observation that Boom Clay deteriorates in contact with air and loses important intrinsic properties formed a major breakthrough in the research and led to a careful examination of the real in-situ conditions. Efforts devoted to the understanding of the chemical factors pertaining to the pH, the redox potential, the extent of the buffering capacity of FeS 2 and CaCO 3 in equilibrium with the interstitial aqueous phase are reviewed. Also emerging from the overall picture was the role of the organic material present in the Boom Clay. In contrast to the water percolating fractured formations which may not be in equilibrium with the rock, the interstitial aqueous phase is completely in equilibrium with Boom Clay mainly because of its low permeability and the large excesses of buffering components. As the retention mechanisms are better understood, a more coherent picture is obtained from distribution and diffusion experiments and the effects of consolidation are being investigated in detail. 23 refs.; 4 figs.; 3 tabs

  13. Review and status of sonic boom penetration into the ocean.

    Science.gov (United States)

    Sparrow, Victor W

    2002-01-01

    Since the 1970 Sonic Boom Symposium, held at the ASA's 80th meeting in Houston, TX, substantial progress has been made in understanding the penetration of sonic booms into the ocean. The state of the art at that time was documented by J. C. Cook, T. Goforth, and R. K. Cook [J. Acoust. Soc. Am. 51, 729-741 (1972)]. Since then, additional experiments have been performed which corroborate Cook's and Sawyers' theory for sonic boom penetration into a flat ocean surface. In addition, computational simulations have validated that theory and extended the work to include arbitrarily shaped waveforms penetrating flat ocean surfaces. Further numerical studies have investigated realistic ocean surfaces including large-scale ocean swell. Research has also been performed on the effects of ocean inhomogeneities due to bubble plumes. This paper provides a brief overview of these developments.

  14. Scattering of sonic booms by anisotropic turbulence in the atmosphere

    Science.gov (United States)

    Kelly; Raspet; Bass

    2000-06-01

    An earlier paper [J. Acoust. Soc. Am. 98, 3412-3417 (1995)] reported on the comparison of rise times and overpressures of sonic booms calculated with a scattering center model of turbulence to measurements of sonic boom propagation through a well-characterized turbulent layer under moderately turbulent conditions. This detailed simulation used spherically symmetric scatterers to calculate the percentage of occurrence histograms of received overpressures and rise times. In this paper the calculation is extended to include distorted ellipsoidal turbules as scatterers and more accurately incorporates the meteorological data into a determination of the number of scatterers per unit volume. The scattering center calculation overpredicts the shifts in rise times for weak turbulence, and still underpredicts the shift under more turbulent conditions. This indicates that a single-scatter center-based model cannot completely describe sonic boom propagation through atmospheric turbulence.

  15. Drilling Down: An Examination of the Boom-Crime Relationship in Resource Based Boom Counties

    Directory of Open Access Journals (Sweden)

    Rick Ruddell

    2017-03-01

    Full Text Available Objective to examine the boomcrime relationship in resourcebased boom counties and to propose socioeconomic and legal measures to reduce the boomtown effect. Methods dialectical approach to cognition of social phenomena allowing to analyze them in historical development and functioning in the context of the totality of objective and subjective factors that determined the choice of the following research methods formallogical comparativelegal survey interview focus groups generalized least squares method. Results The expansion in natural resource development in rural communities has led to a number of social problems in these places. The media community stakeholders as well as law enforcement and human service personnel have reported that the rapid growth in these communities leads to increased crime and other social ills. In order to better understand the boomcrime relationship index crimes in oil and natural gas producing counties in Montana and North Dakota were examined. Comparison of 2012 crime rates in a matched sample of counties revealed that crime rates were higher in oilimpacted counties. A prepost analysis found that violent crime in boom counties increased 18.5 between 2006 and 2012 while decreasing 25.6 in a matched sample of counties that had no oil or gas production. Inconsistent with the media portrayal of these communities as a new quotwild westquot we did not find a significant association between oil or natural gas production and property or violent crime in a series of OLS regression models. Scientific novelty for the first time the article uses index crimes in oil and natural gas producing counties in Montana and North Dakota to reveal the association between the rapid growth of towns and the crime rates. Practical significance the main provisions and conclusions of the article can be used in research and educational activity as well as for predicting the socialeconomic development of boomtowns.

  16. Deformation mechanisms in experimentally deformed Boom Clay

    Science.gov (United States)

    Desbois, Guillaume; Schuck, Bernhard; Urai, Janos

    2016-04-01

    Bulk mechanical and transport properties of reference claystones for deep disposal of radioactive waste have been investigated since many years but little is known about microscale deformation mechanisms because accessing the relevant microstructure in these soft, very fine-grained, low permeable and low porous materials remains difficult. Recent development of ion beam polishing methods to prepare high quality damage free surfaces for scanning electron microscope (SEM) is opening new fields of microstructural investigation in claystones towards a better understanding of the deformation behavior transitional between rocks and soils. We present results of Boom Clay deformed in a triaxial cell in a consolidated - undrained test at a confining pressure of 0.375 MPa (i.e. close to natural value), with σ1 perpendicular to the bedding. Experiments stopped at 20 % strain. As a first approximation, the plasticity of the sample can be described by a Mohr-Coulomb type failure envelope with a coefficient of cohesion C = 0.117 MPa and an internal friction angle ϕ = 18.7°. After deformation test, the bulk sample shows a shear zone at an angle of about 35° from the vertical with an offset of about 5 mm. We used the "Lamipeel" method that allows producing a permanent absolutely plane and large size etched micro relief-replica in order to localize and to document the shear zone at the scale of the deformed core. High-resolution imaging of microstructures was mostly done by using the BIB-SEM method on key-regions identified after the "Lamipeel" method. Detailed BIB-SEM investigations of shear zones show the following: the boundaries between the shear zone and the host rock are sharp, clay aggregates and clastic grains are strongly reoriented parallel to the shear direction, and the porosity is significantly reduced in the shear zone and the grain size is smaller in the shear zone than in the host rock but there is no evidence for broken grains. Comparison of microstructures

  17. Stress Analysis of Boom of Special Mobile Crane for Plain Region in Transmission Line

    Science.gov (United States)

    Qin, Jian; Shao, Tao; Chen, Jun; Wan, Jiancheng; Li, Zhonghuan; Jiang, Ming

    2017-10-01

    Basis of the boom force analysis of special mobile crane for plain region in transmission line, the load type of boom design is confirmed. According to the different combinations of boom sections, the composite pattern of the different boom length is obtained to suit the actual conditions of boom overlapping. The large deformation model is employed with FEM to simulate the stress distribution of boom, and the calculation results are checked. The performance curves of rated load with different arm length and different working range are obtained, which ensures the lifting capacity of special mobile crane meeting the requirement of tower erection of transmission line. The proposed FEM of boom of mobile crane would provide certain guiding and reference to the boom design.

  18. LAVA Simulations for the AIAA Sonic Boom Prediction Workshop

    Science.gov (United States)

    Housman, Jeffrey A.; Sozer, Emre; Moini-Yekta , Shayan; Kiris, Cetin C.

    2014-01-01

    Computational simulations using the Launch Ascent and Vehicle Aerodynamics (LAVA) framework are presented for the First AIAA Sonic Boom Prediction Workshop test cases. The framework is utilized with both structured overset and unstructured meshing approaches. The three workshop test cases include an axisymmetric body, a Delta Wing-Body model, and a complete low-boom supersonic transport concept. Solution sensitivity to mesh type and sizing, and several numerical convective flux discretization choices are presented and discussed. Favorable comparison between the computational simulations and experimental data of nearand mid-field pressure signatures were obtained.

  19. Baby-Boom, Baby-Bust and the Great Depression

    OpenAIRE

    Andriana BELLOU; Emanuela CARDIA

    2015-01-01

    The baby-boom and subsequent baby-bust have shaped much of the history of the second half of the 20th century; yet it is still largely unclear what caused them. This paper presents a new unified explanation of the fertility Boom-Bust that links the latter to the Great Depression and the subsequent economic recovery. We show that the 1929 Crash attracted young married women 20 to 34 years old in 1930 (whom we name D-cohort) in the labor market possibly via an added worker effect. Using several...

  20. Metering Wheel-Wire Track Wire Boom Deployment Mechanism

    Science.gov (United States)

    Granoff, Mark S.

    2014-01-01

    The NASA MMS Spin Plane Double Probe (SDP) Deployer utilizes a helical path, rotating Metering Wheel and a spring loaded Wire "Holding" Track to pay out a "fixed end" 57 meter x 1.5 mm diameter Wire Boom stored between concentric storage cylinders. Unlike rotating spool type storage devices, the storage cylinders remain stationary, and the boom wire is uncoiled along the length of the cylinder via the rotation of the Metering Wheel. This uncoiling action avoids the need for slip-ring contacts since the ends of the wire can remain stationary. Conventional fixed electrical connectors (Micro-D type) are used to terminate to operational electronics.

  1. Hollywood and the Baby Boom: A Social History

    OpenAIRE

    Russell, James A.; Whalley, Jim

    2016-01-01

    Between 1946 and 1964 seventy-five million babies were born, dwarfing the generations that preceded and succeeded them. At each stage of its life-cycle, the baby boom's great size has dictated the terms of national policy and public debate. While aspects of this history are well-documented, the relationship between the baby boom and Hollywood has never been explored. And yet, for almost 40 years, baby boomers made up the majority of Hollywood's audience, and since the 1970s, boomers have domi...

  2. LHC Beam Splash seen by the ATLAS detector - 7 Apr 2015 - Run 260466 - LB 731 - Event 16848

    CERN Multimedia

    ATLAS, EXPERIMENT

    2015-01-01

    Event display of a collimator "splash" event seen by the ATLAS experiment in LHC Run-2, on Tuesday April the 7th 2015: event 16848, run 260466. The collimator position is 140m in front of the ATLAS interaction point. The figure on the left shows an axial view of the various components of the ATLAS detector. The figure on the right shows the energy deposits in the cells of the ATLAS calorimeter.

  3. A model experiment to study sonic boom propagation through turbulence. Part III: validation of sonic boom propagation models.

    Science.gov (United States)

    Lipkens, Bart

    2002-01-01

    In previous papers, we have shown that model experiments are successful in simulating the propagation of sonic booms through the atmospheric turbulent boundary layer. The results from the model experiment, pressure wave forms of spark-produced N waves and turbulence characteristics of the plane jet, are used to test various sonic boom models for propagation through turbulence. Both wave form distortion models and rise time prediction models are tested. Pierce's model [A. D. Pierce, "Statistical theory of atmospheric turbulence effects on sonic boom rise times," J. Acoust. Soc. Am. 49, 906-924 (1971)] based on the wave front folding mechanism at a caustic yields an accurate prediction for the rise time of the mean wave form after propagation through the turbulence.

  4. Modelling, simulation and optimization of agricultural sprayer boom horizontal motion behaviour

    Directory of Open Access Journals (Sweden)

    Anna-Gret Borchert

    2015-08-01

    Full Text Available The study reported here presents a method offering realistic depiction of horizontal motion behaviour of agricultural sprayer booms and for reducing the extent of the simulation model involved. Additionally, various solutions of reducing boom vibrations are presented and compared with the help of simulation. Thereby is demonstrated the extent to which boom motion behaviour on booms with large working widths can be improved through passive vibration absorbers and an active vibration isolation.

  5. Potential Use of BEST® Sediment Trap in Splash - Saltation Transport Process by Simultaneous Wind and Rain Tests.

    Directory of Open Access Journals (Sweden)

    Mustafa Basaran

    Full Text Available The research on wind-driven rain (WDR transport process of the splash-saltation has increased over the last twenty years as wind tunnel experimental studies provide new insights into the mechanisms of simultaneous wind and rain (WDR transport. The present study was conducted to investigate the efficiency of the BEST® sediment traps in catching the sand particles transported through the splash-saltation process under WDR conditions. Experiments were conducted in a wind tunnel rainfall simulator facility with water sprayed through sprinkler nozzles and free-flowing wind at different velocities to simulate the WDR conditions. Not only for vertical sediment distribution, but a series of experimental tests for horizontal distribution of sediments was also performed using BEST® collectors to obtain the actual total sediment mass flow by the splash-saltation in the center of the wind tunnel test section. Total mass transport (kg m-2 were estimated by analytically integrating the exponential functional relationship using the measured sediment amounts at the set trap heights for every run. Results revealed the integrated efficiency of the BEST® traps at 6, 9, 12 and 15 m s-1 wind velocities under 55.8, 50.5, 55.0 and 50.5 mm h-1 rain intensities were, respectively, 83, 106, 105, and 102%. Results as well showed that the efficiencies of BEST® did not change much as compared with those under rainless wind condition.

  6. A second hydrocarbon boom threatens the Peruvian Amazon: trends, projections, and policy implications

    International Nuclear Information System (INIS)

    Finer, Matt; Orta-Martinez, Marti

    2010-01-01

    The Peruvian Amazon is home to extraordinary biological and cultural diversity, and vast swaths of this mega-diverse region remain largely intact. Recent analysis indicates, however, that the rapid proliferation of oil and gas exploration zones now threatens the region's biodiversity, indigenous peoples, and wilderness areas. To better elucidate this dynamic situation, we analyzed official Peruvian government hydrocarbon information and generated a quantitative analysis of the past, present, and future of oil and gas activities in the Peruvian Amazon. We document an extensive hydrocarbon history for the region-over 104 000 km of seismic lines and 679 exploratory and production wells-highlighted by a major exploration boom in the early 1970s. We show that an unprecedented 48.6% of the Peruvian Amazon has been recently covered by oil and gas concessions, up from just 7.1% in 2003. These oil and gas concessions overlap 17.1% of the Peruvian Amazon protected area system and over half of all titled indigenous lands. Moreover, we found that up to 72% of the Peruvian Amazon has been zoned for hydrocarbon activities (concessions plus technical evaluation agreements and proposed concessions) in the past two years, and over 84% at some point during the past 40 years. We project that the recent rapid proliferation of hydrocarbon zones will lead to a second exploration boom, characterized by over 20 000 km of new seismic testing and construction of over 180 new exploratory wells in remote, intact, and sensitive forest areas. As the Peruvian Amazon oil frontier rapidly expands, we conclude that a rigorous policy debate is urgently needed in order to avoid the major environmental impacts associated with the first exploration boom of the 1970s and to minimize the social conflict that recently led to deadly encounters between indigenous protesters and government forces.

  7. A second hydrocarbon boom threatens the Peruvian Amazon: trends, projections, and policy implications

    Energy Technology Data Exchange (ETDEWEB)

    Finer, Matt [Save America' s Forests, 4 Library Court NW, Washington, DC 20003 (United States); Orta-Martinez, Marti, E-mail: matt@saveamericasforests.or, E-mail: martiorta@gmail.co [Institut de Ciencia i Tecnologia Ambiental, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain)

    2010-01-15

    The Peruvian Amazon is home to extraordinary biological and cultural diversity, and vast swaths of this mega-diverse region remain largely intact. Recent analysis indicates, however, that the rapid proliferation of oil and gas exploration zones now threatens the region's biodiversity, indigenous peoples, and wilderness areas. To better elucidate this dynamic situation, we analyzed official Peruvian government hydrocarbon information and generated a quantitative analysis of the past, present, and future of oil and gas activities in the Peruvian Amazon. We document an extensive hydrocarbon history for the region-over 104 000 km of seismic lines and 679 exploratory and production wells-highlighted by a major exploration boom in the early 1970s. We show that an unprecedented 48.6% of the Peruvian Amazon has been recently covered by oil and gas concessions, up from just 7.1% in 2003. These oil and gas concessions overlap 17.1% of the Peruvian Amazon protected area system and over half of all titled indigenous lands. Moreover, we found that up to 72% of the Peruvian Amazon has been zoned for hydrocarbon activities (concessions plus technical evaluation agreements and proposed concessions) in the past two years, and over 84% at some point during the past 40 years. We project that the recent rapid proliferation of hydrocarbon zones will lead to a second exploration boom, characterized by over 20 000 km of new seismic testing and construction of over 180 new exploratory wells in remote, intact, and sensitive forest areas. As the Peruvian Amazon oil frontier rapidly expands, we conclude that a rigorous policy debate is urgently needed in order to avoid the major environmental impacts associated with the first exploration boom of the 1970s and to minimize the social conflict that recently led to deadly encounters between indigenous protesters and government forces.

  8. Effects of sonic booms on breeding gray seals and harbor seals on Sable Island, Canada.

    Science.gov (United States)

    Perry, Elizabeth A; Boness, Daryl J; Insley, Stephen J

    2002-01-01

    The Concorde produces audible sonic booms as it passes 15 km north of Sable Island, Nova Scotia, where gray and harbor seals occur year round. The purpose of this research was to assess how sonic booms affect these seals. The intensity of the booms was measured and three types of data (beach counts, frequency of behavior, and heart rate) were collected before and after booms during the breeding seasons of the two species. In addition to the data taken during breeding, beach counts were made before and after booms during the gray seal moult. The greatest range in overpressure within a single boom was 2.70 psf during gray seal breeding and 2.07 psf during harbor seal breeding. No significant differences were found in the behavior or beach counts of gray seals following sonic booms, regardless of the season. Beach counts and most behaviors of harbor seals also did not differ significantly following booms, however, harbor seals became more vigilant. The heart rates of four gray seal mothers and three pups showed no clear change as a result of booms, but six male harbor seals showed a nonsignificant tendency toward elevated heart rates during the 15-s interval of the boom. These results suggest sonic booms produced by the Concorde, in level flight at altitude and producing on average a sonic boom of 0.9 psf, do not substantially affect the breeding behavior of gray or harbor seals.

  9. Inlet Trade Study for a Low-Boom Aircraft Demonstrator

    Science.gov (United States)

    Heath, Christopher M.; Slater, John W.; Rallabhandi, Sriram K.

    2016-01-01

    Propulsion integration for low-boom supersonic aircraft requires careful inlet selection, placement, and tailoring to achieve acceptable propulsive and aerodynamic performance, without compromising vehicle sonic boom loudness levels. In this investigation, an inward-turning streamline-traced and axisymmetric spike inlet are designed and independently installed on a conceptual low-boom supersonic demonstrator aircraft. The airframe was pre-shaped to achieve a target ground under-track loudness of 76.4 PLdB at cruise using an adjoint-based design optimization process. Aircraft and inlet performance characteristics were obtained by solution of the steady-state Reynolds-averaged Navier-Stokes equations. Isolated cruise inlet performance including total pressure recovery and distortion were computed and compared against installed inlet performance metrics. Evaluation of vehicle near-field pressure signatures, along with under- and off-track propagated loudness levels is also reported. Results indicate the integrated axisymmetric spike design offers higher inlet pressure recovery, lower fan distortion, and reduced sonic boom. The vehicle with streamline-traced inlet exhibits lower external wave drag, which translates to a higher lift-to-drag ratio and increased range capability.

  10. Sonic boom startle effects : report of a field study.

    Science.gov (United States)

    1973-07-01

    The study reports the results of a sonic boom field study conducted in Sweden during October 1972. Ten female subjects were tested indoors on each of six days. Two age groups were studied: 20-35 and 50-65 years. Fighter aircraft flying at various hei...

  11. Environmental Pollution: Noise Pollution - Sonic Boom. Volume I.

    Science.gov (United States)

    Defense Documentation Center, Alexandria, VA.

    The unclassified, annotated bibliography is Volume I of a two-volume set on Noise Pollution - Sonic Boom in a series of scheduled bibliographies on Environmental Pollution. Volume II is Confidential. Corporate author-monitoring agency, subject, title, contract, and report number indexes are included. (Author/JR)

  12. Retirement Prospects of the Baby Boom Generation: A Different Perspective.

    Science.gov (United States)

    Easterlin, Richard A.; And Others

    1990-01-01

    Examined average economic status of baby boom cohorts as they approach retirement using data on their life cycle income experience. Findings suggest that baby boomers are likely to enter old age in better economic position than preboom cohorts because of deferred marriages, reduced childbearing, and increased labor force participation of wives…

  13. Boom clay rheology laboratory and in situ tests

    International Nuclear Information System (INIS)

    Rousset, G.; Bazargan, B.

    1989-01-01

    The mechanical behaviour of Boom clay is characterized by the importance of time dependent effects. Laboratory tests intended to study this behaviour are performed. Viscoplastic solutions are used to model the clay behaviour, 11 parameters entered in the model. The first results of research conducted about the in situ creep behaviour of clays are described. Field tests and laboratory experiment are compared

  14. Societal trends : the aging baby boom and women's increased independence

    Science.gov (United States)

    1997-12-01

    The two most important societal trends today are the aging baby boom and women's increased independence. This paper compares the travel profiles of women aged 40 to 49(early baby boomers) with women aged 75 and over and with men aged 75 and over (par...

  15. Vultures have flown under radar Population boom inspires scientists ...

    African Journals Online (AJOL)

    2007-03-02

    Mar 2, 2007 ... recent years, they've been feasting on the increasing amount of road kill and refuse from Florida's booming growth. Scientists know very little about them, .... allows them to eat rot without getting sick could help prevent or cure human disease, they say. “They have a highly acidic digestive tract from what we.

  16. An aerodynamic design method for generating low sonic-boom pressure signatures

    OpenAIRE

    Makino, Yoshikazu; Aoyama, Takashi; Iwamiya, Toshiyuki; Watanuki, Tadaharu; Kubota, Hirotoshi; 牧野 好和; 青山 剛史; 岩宮 敏幸; 綿貫 忠晴; 久保田 弘敏

    2000-01-01

    A study was conducted of an aerodynamic design for the sonic-boom reduction of supersonic transport. Sonic-boom is one of the most important environmental problems for supersonic transport and methods for reduction of sonic-boom intensity have been published. These previous low sonic-boom design methods utilize the F-function method which is based on a linear theory. In comparison a new low sonic-boom design method is proposed in this study in order to deal with the nonlinear effects of the s...

  17. Sonic Boom Pressure Signature Uncertainty Calculation and Propagation to Ground Noise

    Science.gov (United States)

    West, Thomas K., IV; Bretl, Katherine N.; Walker, Eric L.; Pinier, Jeremy T.

    2015-01-01

    The objective of this study was to outline an approach for the quantification of uncertainty in sonic boom measurements and to investigate the effect of various near-field uncertainty representation approaches on ground noise predictions. These approaches included a symmetric versus asymmetric uncertainty band representation and a dispersion technique based on a partial sum Fourier series that allows for the inclusion of random error sources in the uncertainty. The near-field uncertainty was propagated to the ground level, along with additional uncertainty in the propagation modeling. Estimates of perceived loudness were obtained for the various types of uncertainty representation in the near-field. Analyses were performed on three configurations of interest to the sonic boom community: the SEEB-ALR, the 69o DeltaWing, and the LM 1021-01. Results showed that representation of the near-field uncertainty plays a key role in ground noise predictions. Using a Fourier series based dispersion approach can double the amount of uncertainty in the ground noise compared to a pure bias representation. Compared to previous computational fluid dynamics results, uncertainty in ground noise predictions were greater when considering the near-field experimental uncertainty.

  18. Untamed Jianghu or Emerging Profession: Diagnosing the Psycho-Boom amid China's Mental Health Legislation.

    Science.gov (United States)

    Huang, Hsuan-Ying

    2017-09-25

    This article focuses on the psychotherapy debate in China that was triggered by the country's mental health legislation. Seeing the release of the draft Mental Health Law in 2011 as a "diagnostic event" (Moore in Am Ethnol 14(4):727-736, 1987), I examine the debate in order to unravel the underlying logic and ongoing dynamics of the psycho-boom that has become a conspicuous trend in urban China since the early 2000s. Drawing on my fieldwork in Beijing and Shanghai, I use the two keywords of the debate-"jianghu" (literally "rivers and lakes"), an indigenous term that evokes an untamed realm, and "profession," a foreign concept whose translation requires re-translation-to organize my delineation of its contours. I describe how anticipation of state regulation prompted fears and discontents as well as critical reflections and actions that aimed to transform the field into a profession. The efforts to mark out a professional core against the backdrop of unruly jianghu further faced the challenge of an alternative vision that saw popularization as an equally noble cause. The Mental Health Law came into effect in 2013; ultimately, however, it did not introduce substantive regulation. Finally, I discuss the implications of this debate and the prospects of the psycho-boom.

  19. Plume and Shock Interaction Effects on Sonic Boom in the 1-foot by 1-foot Supersonic Wind Tunnel

    Science.gov (United States)

    Castner, Raymond; Elmiligui, Alaa; Cliff, Susan; Winski, Courtney

    2015-01-01

    The desire to reduce or eliminate the operational restrictions of supersonic aircraft over populated areas has led to extensive research at NASA. Restrictions are due to the disturbance of the sonic boom, caused by the coalescence of shock waves formed by the aircraft. A study has been performed focused on reducing the magnitude of the sonic boom N-wave generated by airplane components with a focus on shock waves caused by the exhaust nozzle plume. Testing was completed in the 1-foot by 1-foot supersonic wind tunnel to study the effects of an exhaust nozzle plume and shock wave interaction. The plume and shock interaction study was developed to collect data for computational fluid dynamics (CFD) validation of a nozzle plume passing through the shock generated from the wing or tail of a supersonic vehicle. The wing or tail was simulated with a wedgeshaped shock generator. This test entry was the first of two phases to collect schlieren images and off-body static pressure profiles. Three wedge configurations were tested consisting of strut-mounted wedges of 2.5- degrees and 5-degrees. Three propulsion configurations were tested simulating the propulsion pod and aft deck from a low boom vehicle concept, which also provided a trailing edge shock and plume interaction. Findings include how the interaction of the jet plume caused a thickening of the shock generated by the wedge (or aft deck) and demonstrate how the shock location moved with increasing nozzle pressure ratio.

  20. Packaging, deployment, and panel design concepts for a truss-stiffened 7-panel precision deployable reflector with feed boom

    Science.gov (United States)

    Heard, Walter L., Jr.; Collins, Timothy J.; Dyess, James W.; Kenner, Scott; Bush, Harold G.

    1993-01-01

    A concept is presented for achieving a remotely deployable truss-stiffened reflector consisting of seven integrated sandwich panels that form the reflective surface, and an integrated feed boom. The concept has potential for meeting aperture size and surface precision requirements for some high-frequency microwave remote sensing applications. The packaged reflector/feed boom configuration is a self-contained unit that can be conveniently attached to a spacecraft bus. The package has a cylindrical envelope compatible with typical launch vehicle shrouds. Dynamic behavior of a deployed configuration having a 216-inch focal length and consisting of 80-inch-diameter, two-inch-thick panels is examined through finite-element analysis. Results show that the feed boom and spacecraft bus can have a large impact on the fundamental frequency of the deployed configuration. Two candidate rib-stiffened sandwich panel configurations for this application are described, and analytical results for panel mass and stiffness are presented. Results show that the addition of only a few rib stiffeners, if sufficiently deep, can efficiently improve sandwich panel stiffness.

  1. Vibration characteristics of a deployable controllable-geometry truss boom

    Science.gov (United States)

    Dorsey, J. T.

    1983-01-01

    An analytical study was made to evaluate changes in the fundamental frequency of a two dimensional cantilevered truss boom at various stages of deployment. The truss could be axially deployed or retracted and undergo a variety of controlled geometry changes by shortening or lengthening the telescoping diagonal members in each bay. Both untapered and tapered versions of the truss boom were modeled and analyzed by using the finite element method. Large reductions in fundamental frequency occurred for both the untapered and tapered trusses when they were uniformly retracted or maneuvered laterally from their fully deployed position. These frequency reductions can be minimized, however, if truss geometries are selected which maintain cantilever root stiffness during truss maneuvers.

  2. Summary of recent NASA studies of human response to sonic booms.

    Science.gov (United States)

    Leatherwood, Jack D; Sullivan, Brenda M; Shepherd, Kevin P; McCurdy, David A; Brown, Sherilyn A

    2002-01-01

    NASA Langley Research Center has conducted three groups of studies on human response to sonic booms: laboratory, "inhome," and field. The laboratory studies were designed to: (1) quantify loudness and annoyance response to a wide range of shaped sonic boom signatures and (2) assess several noise descriptors as estimators of sonic boom subjective effects. The studies were conducted using a sonic boom simulator capable of generating and playing, with high fidelity, both user-prescribed and recorded boom waveforms to test subjects. Results showed that sonic boom waveform shaping provided substantial reductions in loudness and annoyance and that perceived level was the best estimator of subjective effects. Booms having asymmetrical waveforms were found to be less loud than symmetrical waveforms of equivalent perceived level. Subjective responses to simulated ground-reflected waveforms were fully accounted for by perceived level. The inhome study presented participants with simulated sonic booms played within their normal home environment. The results showed that the equal energy theory of annoyance applied to a variety of multiple sonic boom exposures. The field studies concluded that sonic boom annoyance is greater than that in a conventional aircraft noise environment with the same continuous equivalent noise exposure.

  3. Booms petroliers et basculements du rapport de force | Mouhoubi ...

    African Journals Online (AJOL)

    Chacun d'eux ne cherche qu'à instaurer la politique de prix satisfaisant les objectifs inhérents aux stratégies économiques nationales, aux relations internationales ou même s'accaparer de la part la plus importante du surplus pétrolier. Mots-clefs. Boom pétrolier, crise pétrolière, rapport de force, prix dub pétrole. Code Jel ...

  4. Cerveza artesanal : El boom que no para de crecer

    OpenAIRE

    Revista Institucional de la Facultad de Ciencias Económicas

    2015-01-01

    El boom de la cervecería artesanal, que comenzó en Mar del Plata hace ya más de una década, ha tenido un importante epicentro en la ciudad de La Plata, donde la demanda aún supera por amplio margen a la oferta de un mercado en pleno crecimiento. Facultad de Ciencias Económicas

  5. China’s Internet Finance Boom and Tyrannies of Inclusion

    OpenAIRE

    Loubere, Nicholas

    2018-01-01

    One of the main drivers of China’s e-commerce boom is the dramatic expansion of the country’s Internet finance industry, which has grown and diversified at a staggering rate over the past decade. The emergence of Chinese Internet finance has been discussed in largely positive terms as facilitating commercial activity. It has also been linked to the wider developmental goal of promoting financial inclusion through the provision of financial services to previously excluded populations. Emerging...

  6. Unstructured Grids for Sonic Boom Analysis and Design

    Science.gov (United States)

    Campbell, Richard L.; Nayani, Sudheer N.

    2015-01-01

    An evaluation of two methods for improving the process for generating unstructured CFD grids for sonic boom analysis and design has been conducted. The process involves two steps: the generation of an inner core grid using a conventional unstructured grid generator such as VGRID, followed by the extrusion of a sheared and stretched collar grid through the outer boundary of the core grid. The first method evaluated, known as COB, automatically creates a cylindrical outer boundary definition for use in VGRID that makes the extrusion process more robust. The second method, BG, generates the collar grid by extrusion in a very efficient manner. Parametric studies have been carried out and new options evaluated for each of these codes with the goal of establishing guidelines for best practices for maintaining boom signature accuracy with as small a grid as possible. In addition, a preliminary investigation examining the use of the CDISC design method for reducing sonic boom utilizing these grids was conducted, with initial results confirming the feasibility of a new remote design approach.

  7. Influence of Chair Vibrations on Indoor Sonic Boom Annoyance

    Science.gov (United States)

    Rathsam, Jonathan; Klos, Jacob; Loubeau, Alexandra

    2015-01-01

    One goal of NASA’s Commercial Supersonic Technology Project is to identify candidate noise metrics suitable for regulating quiet sonic boom aircraft. A suitable metric must consider the short duration and pronounced low frequency content of sonic booms. For indoor listeners, rattle and creaking sounds and floor and chair vibrations may also be important. The current study examined the effect of such vibrations on the annoyance of test subjects seated indoors. The study involved two chairs exposed to nearly identical acoustic levels: one placed directly on the floor, and the other isolated from floor vibrations by pneumatic elastomeric mounts. All subjects experienced both chairs, sitting in one chair for the first half of the experiment and the other chair for the remaining half. Each half of the experiment consisted of 80 impulsive noises played at the exterior of the sonic boom simulator. When all annoyance ratings were analyzed together there appeared to be no difference in mean annoyance with isolation condition. When the apparent effect of transfer bias was removed, a subtle but measurable effect of vibration on annoyance was identified.

  8. Modelling the interaction of the alkaline plume with Boom Clay at different scales

    International Nuclear Information System (INIS)

    Jacques, Diederik; Wang, Lian

    2012-01-01

    In Belgium, Boom Clay is studied as a potential host formation for geological disposal of high-level radioactive waste. The current reference design of the engineered barrier system ('supercontainer design') plans to use a considerable amount of cementitious materials as construction material, buffer and backfill. Diffusion of the alkaline pore fluids from the concrete engineered barriers to the Boom Clay may change the retention properties of the Boom Clay in the vicinity of the engineered barriers - Boom Clay interface. The objectives of this work are to (i) model the breakthrough curves obtained from leaching small undisturbed Boom Clay cores with young concrete water (high Na and K content, pH 13.5), and (ii) simulate the possible extent of Boom Clay alterations owing to interactions with alkaline fluids for a period of 100,000 years. For both objectives, the reactive transport code PHREEQC is used

  9. Performance study of protective clothing against hot water splashes: from bench scale test to instrumented manikin test.

    Science.gov (United States)

    Lu, Yehu; Song, Guowen; Wang, Faming

    2015-03-01

    Hot liquid hazards existing in work environments are shown to be a considerable risk for industrial workers. In this study, the predicted protection from fabric was assessed by a modified hot liquid splash tester. In these tests, conditions with and without an air spacer were applied. The protective performance of a garment exposed to hot water spray was investigated by a spray manikin evaluation system. Three-dimensional body scanning technique was used to characterize the air gap size between the protective clothing and the manikin skin. The relationship between bench scale test and manikin test was discussed and the regression model was established to predict the overall percentage of skin burn while wearing protective clothing. The results demonstrated strong correlations between bench scale test and manikin test. Based on these studies, the overall performance of protective clothing against hot water spray can be estimated on the basis of the results of the bench scale hot water splashes test and the information of air gap size entrapped in clothing. The findings provide effective guides for the design and material selection while developing high performance protective clothing. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2014.

  10. Applying control volume finite element for modelling direct injection boom spraying flow

    OpenAIRE

    El Aissaoui, Abdellah; Lebeau, Frédéric; Destain, Marie-France; Houmy, Karim

    2009-01-01

    Assessment of injection lag transport and uniformity of direct injection boom sprayer is an important issue for successful variable rate spraying technology. To estimate the boom lag transport and pressure loss, a numerical model is formulated on the basis of fluid hydrodynamic conservation equations. The software is implemented in visual basic. To solve the pressure – velocities equations, control volume finite element method (CV) is used to delimit elementary volumes of the boom. Linearizat...

  11. Predicting transmission of shaped sonic booms into a residential house structure.

    Science.gov (United States)

    Sizov, Natalia V; Plotkin, Kenneth J; Hobbs, Christopher M

    2010-06-01

    Human perception of sonic booms is a major impediment to commercial supersonic flight. Shaping, which reduces the audible shock waves of a boom, can make outdoor perception of booms acceptable. Perception of sonic booms experienced indoors is of concern, and it is not yet established whether shaped booms offer benefit to indoor listeners. A better understanding of the transmission of shaped booms into building structures is needed. In the authors' earlier work the vibration response of house elements subjected to different sonic boom wave shapes was evaluated using a single degree of freedom model. This paper expands that approach with a modal analysis model. The acceleration of building elements and the resulting sound pressure inside a room are computed in the time and frequency domains. Analytical results are compared with experimental data measured by NASA during sonic boom tests conducted at Edwards Air Force Base in 2007. The effects of wave signature parameters on transmission are studied to evaluate the advantages of various kinds of minimized boom shapes.

  12. [Building and testing of Pickard Line-up Boom]. Final progress report

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-31

    The Packard Line-up Boom is a device for controlling the placing together of the ends of two sections of pipe for clamping and welding. Consistently better weld quality is possible because the optimum weld space is achieved and held constant throughout every stringer bead, regardless of the welding method. With the use of the Pickard Line-Up Boom, there will be a minimum of pipe movement while the stringer bead is being run. Since the welder can rely on conditions being the same throughout the weld, he can regulate the weld to eliminate backwelding almost entirely. During the grant period and with the assistance of DOE grant funds, Pickard Line-up Boom Associates (PLUBA) successfully completed Task 1, construction of the Packard Boom. PLUBA contracted with Sawyer Manufacturing Company (1031 North Columbia Place, Tulsa, Oklahoma) to construct the new boom. After completion of the new boom by Sawyer, the boom was successfully tested by PLUBA, thereafter PLUBA attempted to obtain lease agreements with pipeline contractors (Tasks 2 and 3). Toward the end of the project period, PLUBA entered into a license/marketing agreement with Sabre International with. the objective of first securing contracts outside of the United States. Once this is achieved and the Packard Boom is used successfully in the field, it is believed that pipeline contractors may be more willing to use the Packard Boom in the United States.

  13. From boom to bust: small towns and energy development on Colorado's western slope

    Energy Technology Data Exchange (ETDEWEB)

    Gulliford, A.

    Boom towns in western Colorado that felt secure in the nation's need for oil were not prepared for the bust end of the cycle when economics brought oil shale development to a halt. Although changes in the environment, in life styles, and in investment make it more difficult today to weather boom and bust cycles (despite a history of failed mining booms), many small towns are better off than before. They are benefitting from improved local government, public services, and public awareness that will help them prepare for the next energy crisis and its subsequent booms. 10 figures. (DCK)

  14. Bow wave and spray dynamics by a wedge

    OpenAIRE

    Wang, Zhaoyuan; Yang, Jianming; Stern, Frederick

    2010-01-01

    Flows around a wedge-shaped bow are simulated with the aim of investigating the wave breaking mechanism and small scale features of ship bow waves. This fluid dynamics video shows the plunging wave breaking process around the wedge including the thin water sheet formation, overturning sheet with surface disturbance, fingering and breaking up into spray, plunging and splashing, and air entrainment.

  15. Pembuatan Alur Pelayaran dalam Rencana Pelabuhan Marina Pantai Boom, Banyuwangi

    Directory of Open Access Journals (Sweden)

    Muhammad Didi Darmawan

    2017-01-01

    Full Text Available Pantai Boom merupakan pantai yang ada di Kabupaten Banyuwangi. Pantai ini terletak di Kelurahan Kampung Mandar, Kecamatan Banyuwangi, Banyuwangi, Jawa Timur. Pantai tersebut rencananya akan dibangun pelabuhan marina. Pelabuhan harus dilengkapi dengan beberapa fasilitas untuk mendukung rencana tersebut seperti salah satunya adalah alur pelayaran. Untuk membuat alur pelayaran diperlukan penelitian mengenai pasang surut, topografi dasar laut, serta jenis kapal yang melintas untuk memastikan kapal yang berlayar aman dari kemungkinan kecelakaan. Penelitian ini menggunakan data hasil pemeruman, data pasang surut yang diperoleh dari pengamatan langsung, serta berbagai jenis kapal yacht. Hasil dari penelitian ini didapatkan bahwa rencana dermaga sebaiknya dibangun 60 meter menjorok ke arah laut dengan panjang dermaga 25 meter. Dalam keadaan air rendah terendah (LLWL, ketiga jenis kapal yang ditentukan dapat merapat ke rencana Dermaga Pelabuhan Marina Pantai Boom, Banyuwangi. Daerah yang tidak bisa dilewati pada saat LLWL, pada saat MSL daerah tersebut sudah dapat dilewati oleh ketiga jenis kapal tersebut. Pada keadaan muka air tinggi tertinggi (HHWL, Kapal Yacht Class 8 dan 6 dapat melewati sebagian perairan sungai Pantai Boom.         Waktu yang tidak tepat untuk melakukan pelayaran pada saat LLWL dari alur pelayaran yang telah dibuat yaitu antara pukul 04:00 – 06:00 WIB pada saat bulan November 2015-Februari 2016 dan pukul 16:00-18:00 pada saat bulan Juni-Agustus 2016. Sedangkan Waktu yang tepat untuk melakukan pelayaran pada saat HHWL yaitu antara pukul 20:00–23:00 WIB pada saat bulan Desember 2015- Maret 2016 dan pukul 8:00-11:00 pada saat bulan Juni-September 2016.

  16. Did the Aid Boom Pacify Sub-Saharan Africa?

    OpenAIRE

    Azam, Jean-Paul; Thelen, Véronique

    2017-01-01

    The incidence of civil war in Sub-Saharan Africa since the turn of the century is less than half of what it was on average in the last quarter of the 20th century. This paper shows that the aid boom triggered by 9/11 played a key role in achieving purposefully this result using panel data for 46 African countries over four decades. It applies a nearidentification approach to test the aid-conflict tradeoff, taking due account of asymmetric information between the donors and the econometrician....

  17. En las vísperas del boom

    Directory of Open Access Journals (Sweden)

    Tito Drago

    2015-01-01

    Full Text Available La televisión por cable en España está en las vísperas de un boom, de acuerdo a varias investigaciones de mercado y la toma de posiciones de las empresas e instituciones dispuestas a ampararse en las nuevas leyes reguladoras del negocio. La televisión por cable comenzó a funcionar de una manera irregular con los llamados "video comunitarios", éstos surgieron a partir de la instalación de un aparato reproductor de vídeos en grandes edificios de departamentos conectado a cada propietario para alquilar películas.

  18. Display Provides Pilots with Real-Time Sonic-Boom Information

    Science.gov (United States)

    Haering, Ed; Plotkin, Ken

    2013-01-01

    Supersonic aircraft generate shock waves that move outward and extend to the ground. As a cone of pressurized air spreads across the landscape along the flight path, it creates a continuous sonic boom along the flight track. Several factors can influence sonic booms: weight, size, and shape of the aircraft; its altitude and flight path; and weather and atmospheric conditions. This technology allows pilots to control the impact of sonic booms. A software system displays the location and intensity of shock waves caused by supersonic aircraft. This technology can be integrated into cockpits or flight control rooms to help pilots minimize sonic boom impact in populated areas. The system processes vehicle and flight parameters as well as data regarding current atmospheric conditions. The display provides real-time information regarding sonic boom location and intensity, enabling pilots to make the necessary flight adjustments to control the timing and location of sonic booms. This technology can be used on current-generation supersonic aircraft, which generate loud sonic booms, as well as future- generation, low-boom aircraft, anticipated to be quiet enough for populated areas.

  19. Human Response to Low-Intensity Sonic Booms Heard Indoors and Outdoors

    Science.gov (United States)

    Sullivan, Brenda M.; Klos, Jacob; Buehrle, Ralph D.; McCurdy, David A.; Haering, Edward A., Jr.

    2010-01-01

    Test subjects seated inside and outside a house were exposed to low-intensity N-wave sonic booms during a 3-week test period in June 2006- The house was instrumented to measure the booms both inside and out. F-18 aircraft were flown to achieve a variety of boom overpressures from approximately .1 to .6 psf During four test days, seventy-seven test subjects heard the booms while seated inside and outside the house. Using the Magnitude Estimation methodology and artificial reference sounds ; the subjects rated the annoyance of the booms. Since the same subjects heard similar booms both inside and outside the house, comparative ratings of indoor and outdoor annoyance were obtained. For a given metric level, indoor subjects gave higher annoyance scores than outdoor subjects. For a given boom; annoyance scores inside were on average the same as those outside. In a post-test questionnaire, the majority of subjects rated the indoor booms as more annoying than the outdoor ones. These results are discussed in this paper.

  20. Passive diver detection and localization using hydrophones suspended under a boom

    NARCIS (Netherlands)

    Hunter, A.J.; Fillinger, L.; Clarijs, M.C.

    2013-01-01

    A boom is a line of floats that constitutes a physical barrier for providing abovewater stopping power. However, it does not provide any situation awareness. In order to overcome this shortcoming, an integrated “booms and sensors” solution using passive sonar was conceived and tested experimentally

  1. Continued development of a test for fire booms in waves and flames

    International Nuclear Information System (INIS)

    McCourt, J.; Buist, I.; Mullin, J.

    1998-01-01

    The durability of a fire resistant boom and its ability to contain oil during an in situ burn without creating any environmental damage as a result of the burning crude was evaluated. The screening test included four stages: (1) the pre-burn wave stress stage, where the test boom was flexed under tension in waves to simulate deployment of the boom and transit to the spill site, (2) the burn in wave stage, where the test boom was exposed to waves and repeated on hourly cycles of a propane gas fire to simulate oil burning operations, (3) the post-burn wave stress stage, where the test boom was again flexed under tension in waves to simulate retrieval of the boom, and (4) the oil-containment stage, where the ability of the boom to contain thick pools of hot oil was assessed. Three recommendations were made after the test program: (1) increase the heat generated by fire, (2) increase the tension on the boom, and (4) improve the data acquisition system. 10 refs., 10 tabs., 13 figs

  2. Measuring and explaining the baby boom in the developed world in the mid-twentieth century

    Directory of Open Access Journals (Sweden)

    Jesús J. Sánchez-Barricarte

    2018-03-01

    Full Text Available Background: The early research on the baby boom tried to account for it as a logical recovery following the end of the Second World War (WWII. But it cannot be understood merely as a post-war phenomenon because its origins go back to the 1930s and early 1940s. Objective: I shall describe the methodology used to measure the total and marital baby boom and provide a detailed description of it. I shall attempt to explain the possible reasons that led to the sharp increase in the marital fertility rates and its subsequent decline. Methods: I will use various fertility indices that track the historical development of fertility (total and marital; period and cohort. Results: I show that there are major differences in the measurement of the baby boom depending on the index used. I found that the baby boom is highly heterogeneous in the 25 countries that form part of my study. It represented the logical response that families made to one period of prolonged political, economic, and military crisis (the crash of 1929 and WWII. Conclusions: Researchers who use only the total fertility indices are really analysing only the nuptiality boom, which took place during those years, rather than changes in reproductive behaviour. Contribution: I measure total and marital baby boom for 25 developed countries and perform the calculations to measure the impact of marital fertility and nuptiality on the total baby boom (TBB. I present a new explanation of the origins of the baby boom.

  3. Effectiveness of elastic damping in the pivot joints of cargo boom of crane-manipulating installations at large gaps

    Directory of Open Access Journals (Sweden)

    Lagerev I.A.

    2016-03-01

    Full Text Available The article was the analysis of dynamic processes in the cylindrical hinges with large gaps in the cargo boom crane-manipulating installations of mobile machines in operation. Consider the design of damping device for articulated joints, which creates a braking force of elastic resistance to the displacement of the hinge pin within the large gap. The mechanism of action of the damping devices was considered. Analysis of the effectiveness of damping device for re-ducing the dynamic stress state in the elements of cargo boom metal structures depending on the gap size and the stiff-ness of the damping device was performed. Damping device with an elastic shock absorbing elements substantially reduces the additional impact load at the time of selection of the gap in the joint, slow the growth of clearance in the pivot joint, limit the size of the gap specified value, which must not be exceeded during the entire service life of swivel independently from the intensity of his load.

  4. Underwater measurements and modeling of a sonic boom.

    Science.gov (United States)

    Desharnais, Francine; Chapman, David M F

    2002-01-01

    During a sea trial on the Scotian Shelf, acoustic signals from a sonic boom were recorded on 11 hydrophones of a vertical array. The array spanned the lower 50 m of the water column above a sand bank at 76 m water depth. The source of the sonic boom was deduced to be a Concorde supersonic airliner traveling at about Mach 2. The waterborne waveform was observed to decay as an evanescent wave below the sea surface, as expected. The calm weather (sea state 1) resulted in low ambient noise and low self-noise at the hydrophones, and good signal-to-noise ratio on the upper hydrophones; however, the decreased signal amplitude is more difficult to detect towards the lower part of the water column. The period of the observed waveform is of the order 0.23 s, corresponding to a peak frequency of about 3 Hz. The shape of the measured waveform differs noticeably from the theoretical N-shape waveform predicted with Sawyers' theory [J. Acoust. Soc. Am. 44, 523-524 (1968)]. A simple shallow-ocean geoacoustic model suggests that this effect may be caused in part by seismo-acoustic interaction of the infrasonic waves with the elastic sediments that form the seabed.

  5. Boom bomer boomste en die idiolek van Elsabe Steenberg

    Directory of Open Access Journals (Sweden)

    Elizabeth S. van der Westhuizen

    2014-12-01

    Full Text Available Boom bomer boomste and the idiolect of Elsabe Steenberg. Elsabe Steenberg’s oeuvre,consisting among others of 42 narratives in book format, is richly textured and represents a notable depth of insight into the complexities of life. It is clear that, from an intertextual point of view, considering the entire body of her work is a way of accumulating evidence in order to discern aspects of her distinctive idiolect. This idiolect, however, also emerges when contemplating a representative work from her oeuvre. The text selected for this article, a youth novel in which the symbolism of trees manifests itself in various semantic permutations,communicating the author’s intrinsic life and world view, is Boom bomer boomste, also available in English under the title Tree-more, tree-most. The tree as object and how it functions in the narrative to become part of the theme, as well as the vision of life in this youth novel, can be scrutinised minutely if the effort is aimed at finding frequent recurring signs that maybe regarded as representative of the author’s idiolect. The use of the tree symbolism in the narrative worlds of Elsabe Steenberg points toward the most prolific sign contributing to this author’s idiolect: God is the Origin and the regenerating Force in the universe of Elsabe Steenberg’s life and work.

  6. Micro-Ramps for External Compression Low-Boom Inlets

    Science.gov (United States)

    Rybalko, Michael; Loth, Eric; Chima, Rodrick V.; Hirt, Stefanie M.; DeBonis, James R.

    2010-01-01

    The application of vortex generators for flow control in an external compression, axisymmetric, low-boom concept inlet was investigated using RANS simulations with three-dimensional (3-D), structured, chimera (overset) grids and the WIND-US code. The low-boom inlet design is based on previous scale model 1- by 1-ft wind tunnel tests and features a zero-angle cowl and relaxed isentropic compression centerbody spike, resulting in defocused oblique shocks and a weak terminating normal shock. Validation of the methodology was first performed for micro-ramps in supersonic flow on a flat plate with and without oblique shocks. For the inlet configuration, simulations with several types of vortex generators were conducted for positions both upstream and downstream of the terminating normal shock. The performance parameters included incompressible axisymmetric shape factor, separation area, inlet pressure recovery, and massflow ratio. The design of experiments (DOE) methodology was used to select device size and location, analyze the resulting data, and determine the optimal choice of device geometry. The optimum upstream configuration was found to substantially reduce the post-shock separation area but did not significantly impact recovery at the aerodynamic interface plane (AIP). Downstream device placement allowed for fuller boundary layer velocity profiles and reduced distortion. This resulted in an improved pressure recovery and massflow ratio at the AIP compared to the baseline solid-wall configuration.

  7. Sound, infrasound, and sonic boom absorption by atmospheric clouds.

    Science.gov (United States)

    Baudoin, Michaël; Coulouvrat, François; Thomas, Jean-Louis

    2011-09-01

    This study quantifies the influence of atmospheric clouds on propagation of sound and infrasound, based on an existing model [Gubaidulin and Nigmatulin, Int. J. Multiphase Flow 26, 207-228 (2000)]. Clouds are considered as a dilute and polydisperse suspension of liquid water droplets within a mixture of dry air and water vapor, both considered as perfect gases. The model is limited to low and medium altitude clouds, with a small ice content. Four physical mechanisms are taken into account: viscoinertial effects, heat transfer, water phase changes (evaporation and condensation), and vapor diffusion. Physical properties of atmospheric clouds (altitude, thickness, water content and droplet size distribution) are collected, along with values of the thermodynamical coefficients. Different types of clouds have been selected. Quantitative evaluation shows that, for low audible and infrasound frequencies, absorption within clouds is several orders of magnitude larger than classical absorption. The importance of phase changes and vapor diffusion is outlined. Finally, numerical simulations for nonlinear propagation of sonic booms indicate that, for thick clouds, attenuation can lead to a very large decay of the boom at the ground level. © 2011 Acoustical Society of America

  8. Ornamental Bedding Plants Industry in Japan: Changes in Production, Distribution and Consumption after the Gardening Boom of 1990's

    OpenAIRE

    Miyabe, kazuyuki; Niisato, Yasutaka

    2010-01-01

    The ornamental bedding plants in Japan experienced a gardening boom that peaked in 1999.The gardening boom of 1990’s had a profound effect in the bedding plants market in Japan, which historically had tended to increase gradually, increased dramatically both in quantity and quality.However, supply and demand shifted to the saturated condition after the gardening boom. Established diversity and the variation were demanded at the boom. The accumulation and use of joint ownership type informatio...

  9. Reactions to sonic booms: a report of two studies and a general evaluation of startle effects.

    Science.gov (United States)

    Thackray, R I; Touchstone, R M; Bailey, J P

    1975-04-01

    Two separate studies are reported. The first attempted to determine a sonic boom level below which startle would not occurr. Subjects were exposed indoors to six simulated sonic booms having outside overpressures of 50, 30, and 16 N/m-2 (inside levels of 74, 71, and 65 dBA). Approximately 20% of the subjects gave small arm-hand responses to the two higher exposure levels, while none responded to the lowest level. In the second study, subjects were exposed indoors to a series of 12 simulated booms in order to assess habituation effects. Outside overpressures were 130 and 50 N/m-2 (indoor levels of 81 and 72 dBA). Significant, but not complete, habituation occurred to booms of both levels. Autonomic and eyeblink responses, as well as ratings of annoyance, were obtained in both studies. The final section summarizes the expected behavioral, autonomic, and subjective effects of exposure to various levels of sonic booms.

  10. Generation of Parametric Equivalent-Area Targets for Design of Low-Boom Supersonic Concepts

    Science.gov (United States)

    Li, Wu; Shields, Elwood

    2011-01-01

    A tool with an Excel visual interface is developed to generate equivalent-area (A(sub e)) targets that satisfy the volume constraints for a low-boom supersonic configuration. The new parametric Ae target explorer allows users to interactively study the tradeoffs between the aircraft volume constraints and the low-boom characteristics (e.g., loudness) of the ground signature. Moreover, numerical optimization can be used to generate the optimal A(sub e) target for given A(sub e) volume constraints. A case study is used to demonstrate how a generated low-boom Ae target can be matched by a supersonic configuration that includes a fuselage, wing, nacelle, pylon, aft pod, horizontal tail, and vertical tail. The low-boom configuration is verified by sonic-boom analysis with an off-body pressure distribution at three body lengths below the configuration

  11. Gravity-gradient dynamics experiments performed in orbit utilizing the Radio Astronomy Explorer (RAE-1) spacecraft

    Science.gov (United States)

    Walden, H.

    1973-01-01

    Six dynamic experiments were performed in earth orbit utilizing the RAE spacecraft in order to test the accuracy of the mathematical model of RAE dynamics. The spacecraft consisted of four flexible antenna booms, mounted on a rigid cylindrical spacecraft hub at center, for measuring radio emissions from extraterrestrial sources. Attitude control of the gravity stabilized spacecraft was tested by using damper clamping, single lower leading boom operations, and double lower boom operations. Results and conclusions of the in-orbit dynamic experiments proved the accuracy of the analytic techniques used to model RAE dynamical behavior.

  12. The study of abiotic reduction of nitrate and nitrite in Boom Clay

    Science.gov (United States)

    Mariën, A.; Bleyen, N.; Aerts, S.; Valcke, E.

    In Belgium, Boom Clay is studied as a reference host rock for the geological disposal of high-level and intermediate-level radioactive waste. Compatibility studies at the SCK•CEN aim at investigating a perturbation of the capacity of Boom Clay to retard the migration of radionuclides to the biosphere, after disposal of Eurobitum bituminized radioactive waste in the clay ( Valcke et al., 2009; Aertsens et al., 2009; Bleyen et al., 2010). One of the geo-chemical perturbations is the possible oxidation of Boom Clay by the large amounts of nitrate that will be released by Eurobitum. A more oxidised Boom Clay could have a lower reducing capacity towards redox sensitive radionuclides, possibly enhancing their migration. As the conditions in the Boom Clay formation around a disposal gallery for Eurobitum are far from optimal for the growth of prokaryotes (limited space in the far-field, high pH in the near-field, gamma radiation by the waste during the first ∼300 years (effect limited to the primary and secondary waste package)), the impact of microbially mediated reduction of nitrate and nitrite is unclear. Therefore, batch tests are performed at the SCK•CEN to study whether nitrate and nitrite can directly oxidise the main redoxactive components of Boom Clay (dissolved organic matter, kerogen, pyrite) without the mediation of prokaryotes. In a first series of batch tests, which are reported in this paper, the activity of denitrifying and nitrate reducing prokaryotes was inhibited by the addition of NaN 3. NaN 3 revealed to be an efficient inhibitor for these prokaryotes without affecting considerably the geochemistry of Boom Clay and/or Boom Clay pore water. Neither in batch tests with the Boom Clay slurries (with NaNO 3 (0.1 and 1 M) or NaNO 2 (0.1 M)) and with Boom Clay water (with 0.05 and 0.2 M NaNO 3) a pure chemical nitrate or nitrite reduction was observed after respectively 3, 7 and 17 weeks and 1 year (Boom Clay slurries) and about 2 years (Boom Clay

  13. Mindfulness as a booming, diverse and (non) religious phenomenon

    DEFF Research Database (Denmark)

    Borup, Jørn

    2016-01-01

    Mindfulness has become a phenomenon with widespread appeal in many Western countries. Like yoga, it has an Eastern religious origin, but through a long history it has been transformed and adapted to new cultural and social contexts. While the majority of research on mindfulness has been conducted...... within the health sciences, the aim of this article is to investigate the distribution, meaning and function of this practice through quantitative mapping and qualitative interviews with 16 mindfulness providers in the city of Aarhus in Denmark. The analysis reveals not just a booming phenomenon......, but also a field characterized by diversity in terms of authority claims, motivations and uses. The discussion focuses on whether mindfulness can be seen as a religious practice or as a typical expression of an individualized and secularized technique....

  14. Homogeneity vs. Heterogeneity of Porosity in Boom Clay

    International Nuclear Information System (INIS)

    Hemes, Susanne; Desbois, Guillaume; Urai, Janos L.; De Craen, Mieke; Honty, Miroslav

    2013-01-01

    Microstructural investigations on Boom Clay at nano- to micrometer scale, using BIB-SEM methods, result in porosity characterization for different mineral phases from direct observations on high resolution SE2-images of representative elementary areas (REAs). High quality, polished surfaces of cross-sections of ∼ 1 mm 2 size were produced on three different samples from the Mol-Dessel research site (Belgium). More than 33,000 pores were detected, manually segmented and analyzed with regard to their size, shape and orientation. Two main pore classes were defined: Small pores (< 500 nm (ED)) within the clay matrices of samples and =big' pores (> 500 nm (ED)) at the interfaces between clay and non-clay mineral (NCM) grains. Samples investigated show similar porosities regarding the first pore-class, but differences occur at the interfaces between clay matrix and NCM grains. These differences were interpreted to be due to differences in quantitative mineralogy (amount of non-clay mineral grains) and grain-size distributions between samples investigated. Visible porosities were measured as 15 to 17 % for samples investigated. Pore-size distributions of pores in clay are similar for all samples, showing log-normal distributions with peaks around 60 nm (ED) and more than 95 % of the pores being smaller than 500 nm (ED). Fitting pore-size distributions using power-laws with exponents between 1.56 and 1.7, assuming self-similarity of the pore space, thus pores smaller than the pore detection resolution following the same power-laws and using these power-laws for extrapolation of pore-size distributions below the limit of pore detection resolution, results in total estimated porosities between 20 and 30 %. These results are in good agreement with data known from Mercury Porosimetry investigations (35-40 % porosity) and water content porosity measurements (∼ 36 %) performed on Boom Clay. (authors)

  15. Laboratory Headphone Studies of Human Response to Low-Amplitude Sonic Booms and Rattle Heard Indoors

    Science.gov (United States)

    Loubeau, Alexandra; Sullivan, Brenda M.; Klos, Jacob; Rathsam, Jonathan; Gavin, Joseph R.

    2013-01-01

    Human response to sonic booms heard indoors is affected by the generation of contact-induced rattle noise. The annoyance caused by sonic boom-induced rattle noise was studied in a series of psychoacoustics tests. Stimuli were divided into three categories and presented in three different studies: isolated rattles at the same calculated Perceived Level (PL), sonic booms combined with rattles with the mixed sound at a single PL, and sonic booms combined with rattles with the mixed sound at three different PL. Subjects listened to sounds over headphones and were asked to report their annoyance. Annoyance to different rattles was shown to vary significantly according to rattle object size. In addition, the combination of low-amplitude sonic booms and rattles can be more annoying than the sonic boom alone. Correlations and regression analyses for the combined sonic boom and rattle sounds identified the Moore and Glasberg Stationary Loudness (MGSL) metric as a primary predictor of annoyance for the tested sounds. Multiple linear regression models were developed to describe annoyance to the tested sounds, and simplifications for applicability to a wider range of sounds are presented.

  16. Subjective response of people to simulated sonic booms in their homes.

    Science.gov (United States)

    McCurdy, David A; Brown, Sherilyn A; Hilliard, R David

    2004-09-01

    In order to determine the effect of the number of sonic boom occurrences on annoyance, a computer-based system was developed for studying the subjective response of people to the occurrence of simulated sonic booms in their homes. The system provided a degree of control over the noise exposure not found in community surveys and a degree of situational realism not available in the laboratory. A system was deployed for eight weeks in each of 33 homes. Each day from 4 to 63 sonic booms were played as the test subject went about his or her normal activities. At the end of the day, the test subjects rated their annoyance to the sonic booms heard during the day. The sonic booms consisted of different combinations of waveforms, levels, and occurrence rates. The experiment confirmed that the increase in annoyance resulting from multiple occurrences can be modeled by the addition of the term "10 * log(number of occurrences)" to the sonic boom level. Of several noise metrics considered, perceived level was the best annoyance predictor. Comparisons of the subjective responses to the different sonic boom waveforms found no differences that were not accounted for by the noise metrics.

  17. Boom clay pore water, home of a diverse microbial community

    International Nuclear Information System (INIS)

    Wouters, Katinka; Moors, Hugo; Leys, Natalie

    2012-01-01

    Document available in extended abstract form only. Boom Clay pore water (BCPW) has been studied in the framework of geological disposal of nuclear waste for over two decades, thereby mainly addressing its geochemical properties. A reference composition for synthetic clay water has been derived earlier by modelling and spatial calibration efforts, mainly based on interstitial water sampled from different layers within the Boom clay. However, since microbial activity is found in a range of extreme circumstances, the possibility of microbes interacting with future radioactive waste in a host formation like Boom Clay, cannot be ignored. In this respect, BCPW was sampled from different Boom Clay layers using the Morpheus piezometer and subsequently analysed by a complementary set of microbiological and molecular techniques, in search for overall shared and abundant microorganisms. Similar to the previous characterization of the 'average' BCPW chemical composition, the primary aim of this microbiological study is to determine a representative BCPW microbial community which can be used in laboratory studies. Secondly, the in situ activity and the metabolic properties of members of this community were addressed, aiming to assess their survival and proliferation chances in repository conditions. In a first approach, total microbial DNA of the community was extracted from the BCPW samples. This molecular approach allows a broad insight in the total microbial ecology of the BCPW samples. By polymerase chain reaction (PCR) on the highly conserved 16S rRNA genes in this DNA pool and subsequent sequencing and bio-informatics analysis, operational taxonomic units (OTUs) could be assigned to the microbial community. The bacterial community was found to be quite diverse, with OTUs belonging to 8 different phyla (Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, Chlorobi, Spirochetes, Chloroflexi and Deinococcus-Thermus). These results provide an overall view of the

  18. effects of rainfall intensity and slope angle on splash erosion in ...

    African Journals Online (AJOL)

    user

    Geoderma (69): 85-103. Valmis, S. Dimoyiannis, D and Danalatas, N. G., 2005. Assessing Interrill Erosion rate from Soil. Aggregate Instability Indus, Rainfall Intensity ad. Slope Angle on Cultivated Soils in Central. Greece; Soil and Tillage Research. 80, 139-147. Van Dijk., A. I. J. M., 2002. Water & Sediment Dynamics.

  19. Methodology for the Regulation of Boom Sprayers Operating in Circular Trajectories

    Directory of Open Access Journals (Sweden)

    Alfredo Serreta

    2011-04-01

    Full Text Available A methodology for the regulation of boom sprayers working in circular trajectories has been developed. In this type of trajectory, the areas of the plots of land treated by the outer nozzles of the boom are treated at reduced rates, and those treated by the inner nozzles are treated in excess. The goal of this study was to establish the methodology to determine the flow of the individual nozzles on the boom to guarantee that the dose of the product applied per surface unit is similar across the plot. This flow is a function of the position of the equipment (circular trajectory radius and of the displacement velocity such that the treatment applied per surface unit is uniform. GPS technology was proposed as a basis to establish the position and displacement velocity of the tractor. The viability of this methodology was simulated considering two circular plots with radii of 160 m and 310 m, using three sets of equipment with boom widths of 14.5, 24.5 and 29.5 m. Data showed as increasing boom widths produce bigger errors in the surface dose applied (L/m2. Error also increases with decreasing plot surface. As an example, considering the three boom widths of 14.5, 24.5 and 29.5 m working on a circular plot with a radius of 160 m, the percentage of surface with errors in the applied surface dose greater than 5% was 30%, 58% and 65% respectively. Considering a circular plot with radius of 310 m the same errors were 8%, 22% and 31%. To obtain a uniform superficial dose two sprayer regulation alternatives have been simulated considering a 14.5 m boom: the regulation of the pressure of each nozzle and the regulation of the pressure of each boom section. The viability of implementing the proposed methodology on commercial boom sprayers using GPS antennas to establish the position and displacement velocity of the tractor was justified with a field trial in which a self-guiding commercial GPS system was used along with three precision GPS systems located in

  20. Thermo-hydro-mechanical behaviour of Boom clay; Comportement thermo-hydro-mecanique de l'argile de Boom

    Energy Technology Data Exchange (ETDEWEB)

    Le, T.T

    2008-01-15

    This thesis studied the thermo-hydro-mechanical properties of Boom clay, which was chosen to be the host material for the radioactive waste disposal in Mol, Belgium. Firstly, the research was concentrated on the soil water retention properties and the hydro-mechanical coupling by carrying out axial compression tests with suction monitoring. The results obtained permitted elaborating a rational experimental procedure for triaxial tests. Secondly, the systems for high pressure triaxial test at controlled temperature were developed to carry out compression, heating, and shearing tests at different temperatures. The obtained results showed clear visco-elasto-plastic behaviour of the soil. This behaviour was modelled by extending the thermo-elasto-plastic model of Cui et al. (2000) to creep effect. (author)

  1. An Experimental Study of Sonic Boom Penetration Under a Wavy Air-Water Interface

    National Research Council Canada - National Science Library

    Fincham, Adam; Maxworthy, Tony

    2002-01-01

    A laboratory experiment was designed and performed to ascertain the difference in underwater response to sonic boom laboratory between flat and wavy surface models and their depth-dependent rule overpressure attenuation...

  2. Sonic Boom Vibro-Acoustic Simulations using Multiple Point Sources Project

    Data.gov (United States)

    National Aeronautics and Space Administration — AVEC proposes an innovative concept for the evaluation of human response studies to sonic booms inside realistic structures. The approach proposed is to simulate the...

  3. An ElectroAdhesive "Stick Boom" for Mars Sample Return Orbiting Sample Capture, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Electroadhesive "Sticky Boom", an innovative method for rendezvous and docking, is proposed for the Orbiting Sample Capture (OSC) portion of the Mars Sample...

  4. 75 FR 49843 - Regulated Navigation Area; Boom Deployment Strategy Testing, Great Bay, NH

    Science.gov (United States)

    2010-08-16

    ... will be marked with 32-inch floating balls to make the ends of each boom segment more visible to... east, a line drawn between the easternmost end of the Scammel Bridge (Route 4) in position 43[deg]07'41...

  5. Simplified High-Performance Roll Out Composite Magnetometer Boom, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to NASA's need for compact, low-cost deployable magnetometer booms for CubeSats, Roccor proposes to develop a Simple High-performance Roll-Out Composite...

  6. Langley's Computational Efforts in Sonic-Boom Softening of the Boeing HSCT

    Science.gov (United States)

    Fouladi, Kamran

    1999-01-01

    NASA Langley's computational efforts in the sonic-boom softening of the Boeing high-speed civil transport are discussed in this paper. In these efforts, an optimization process using a higher order Euler method for analysis was employed to reduce the sonic boom of a baseline configuration through fuselage camber and wing dihedral modifications. Fuselage modifications did not provide any improvements, but the dihedral modifications were shown to be an important tool for the softening process. The study also included aerodynamic and sonic-boom analyses of the baseline and some of the proposed "softened" configurations. Comparisons of two Euler methodologies and two propagation programs for sonic-boom predictions are also discussed in the present paper.

  7. An evaluation of propane as a fuel for testing fire-resistant oil spill containment booms

    International Nuclear Information System (INIS)

    Walton, W. D.; Twilley, W. H.

    1997-01-01

    A series of experiments have been conducted to measure and compare the thermal exposure to a fire-resistant boom from liquid hydrocarbon fuel and propane fires. The objective was to test the potential of propane fueled fires as a fire source for testing fire-resistant oil spill containment booms.Thermal exposure from propane fires have been measured with and without waves. Results indicated that although propane diffusion flames on water look like liquid hydrocarbon fuel flames and produce very little smoke, the heat flux at the boom location from propane fires is about 60 per cent of that from liquid hydrocarbon fuel fires. Despite the attractive features in terms of ease of application, control and smoke emissions, it was concluded that the low heat flux would preclude the application of propane as a fuel for evaluating fire resistant containment booms. 2 refs., 7 figs

  8. The marriage boom and marriage bust in the United States: An age-period-cohort analysis.

    Science.gov (United States)

    Schellekens, Jona

    2017-03-01

    In the 1950s and 1960s there was an unprecedented marriage boom in the United States. This was followed in the 1970s by a marriage bust. Some argue that both phenomena are cohort effects, while others argue that they are period effects. The study reported here tested the major period and cohort theories of the marriage boom and bust, by estimating an age-period-cohort model of first marriage for the years 1925-79 using census microdata. The results of the analysis indicate that the marriage boom was mostly a period effect, although there were also cohort influences. More specifically, the hypothesis that the marriage boom was mostly a response to rising wages is shown to be consistent with the data. However, much of the marriage bust can be accounted for by unidentified cohort influences, at least until 1980.

  9. Summary and Statistical Analysis of the First AIAA Sonic Boom Prediction Workshop

    Science.gov (United States)

    Park, Michael A.; Morgenstern, John M.

    2014-01-01

    A summary is provided for the First AIAA Sonic Boom Workshop held 11 January 2014 in conjunction with AIAA SciTech 2014. Near-field pressure signatures extracted from computational fluid dynamics solutions are gathered from nineteen participants representing three countries for the two required cases, an axisymmetric body and simple delta wing body. Structured multiblock, unstructured mixed-element, unstructured tetrahedral, overset, and Cartesian cut-cell methods are used by the participants. Participants provided signatures computed on participant generated and solution adapted grids. Signatures are also provided for a series of uniformly refined workshop provided grids. These submissions are propagated to the ground and loudness measures are computed. This allows the grid convergence of a loudness measure and a validation metric (dfference norm between computed and wind tunnel measured near-field signatures) to be studied for the first time. Statistical analysis is also presented for these measures. An optional configuration includes fuselage, wing, tail, flow-through nacelles, and blade sting. This full configuration exhibits more variation in eleven submissions than the sixty submissions provided for each required case. Recommendations are provided for potential improvements to the analysis methods and a possible subsequent workshop.

  10. Formulation of the problem of sonic boom by a maneuvering aerofoil ...

    Indian Academy of Sciences (India)

    from the aircraft. The N-wave signature of a boom is modified to a U-wave signature in a focused boom produced by an accelerating aircraft (or more generally a maneuvering aircraft, figure 3 of [10]), ..... method of wavefront construction i.e., the line joining the tips of the rays at time t in the. (x,y)-plane starting from all ...

  11. SUSTAINABILITY IN FISCAL POLICY IN BOOM AND RECESSION-THE CASE OF ROMANIA

    OpenAIRE

    Mihaela GÖNDÖR

    2013-01-01

    This paper examines the interrelated aspects of the recent economic and fiscal crisis – such as the GDP growth, budgetary deficit and public debt, fiscal policy and austerity measures in Romania by comparing the different effects caused by different fiscal policies within a boom period and a downturn period. The paper reveals that the boom period is characterized by tax rate cuts and rising of expenditures and the downturn period, by the increasing of fiscal burden and sharply reducing the go...

  12. A computational analysis of sonic booms penetrating a realistic ocean surface.

    Science.gov (United States)

    Rochat, J L; Sparrow, V W

    2001-03-01

    The last decade has seen a revival of sonic boom research, a direct result of the projected market for a new breed of supersonic passenger aircraft, its design, and its operation. One area of the research involves sonic boom penetration into the ocean, one concern being the possible disturbance of marine mammals from the noise generated by proposed high-speed civil transport (HSCT) flyovers. Although theory is available to predict underwater sound levels due to a sonic boom hitting a homogeneous ocean with a flat surface, theory for a realistic ocean, one with a wavy surface and bubbles near the surface, is missing and will be presented in this paper. First, reviews are given of a computational method to calculate the underwater pressure field and the effects of a simple wavy ocean surface on the impinging sonic boom. Second, effects are described for the implementation of three additional conditions: a sonic boom/ocean "wavelength" comparison, complex ocean surfaces, and bubbles near the ocean surface. Overall, results from the model suggest that the realistic ocean features affect the penetrating proposed HSCT sonic booms by modifying the underwater sound-pressure levels only about 1 decibel or less.

  13. An analysis of the response of Sooty Tern eggs to sonic boom overpressures.

    Science.gov (United States)

    Ting, Carina; Garrelick, Joel; Bowles, Ann

    2002-01-01

    It has been proposed that sonic booms caused a mass hatching failure of Sooty Terns in the Dry Tortugas in Florida by cracking the eggshells. This paper investigates this possibility analytically, complementing previous empirical studies. The sonic boom is represented as a plane-wave excitation with an N-wave time signature. Two models for the egg are employed. The first model, intended to provide insight, consists of a spherical shell, with the embryo represented as a rigid, concentric sphere and the albumen as an acoustic fluid filling the intervening volume. The substrate is modeled as a doubling of the incident pressure. The second, numerical model includes the egg-shape geometry and air sac. More importantly, the substrate is modeled as a rigid boundary of infinite extent with acoustic diffraction included. The peak shell stress, embryo acceleration, and reactive force are predicted as a function of the peak sonic boom overpressure and compared with damage criteria from the literature. The predicted peak sonic boom overpressure necessary for egg damage is much higher than documented sonic boom overpressures, even for extraordinary operational conditions. Therefore, as with previous empirical studies, it is concluded that it is unlikely that sonic boom overpressures damage avian eggs.

  14. USAF Flight Test Investigation of Focused Sonic Booms: Project Have Bears

    Science.gov (United States)

    Downing, Micah; Zamot, Noel; Moss, Chris; Morin, Daniel; Wolski, Ed; Chung, Sukhwan; Plotkin, Kenneth; Maglieri, Domenic

    1996-01-01

    Supersonic operations from military aircraft generate sonic booms that can affect people, animals and structures. A substantial experimental data base exists on sonic booms for aircraft in steady flight and confidence in the predictive techniques has been established. All the focus sonic boom data that are in existence today were collected during the 60's and 70's as part of the information base to the US Supersonic Transport program and the French Jericho studies for the Concorde. These experiments formed the data base to develop sonic boom propagation and prediction theories for focusing. There is a renewed interest in high-speed transports for civilian application. Moreover, today's fighter aircraft have better performance capabilities, and supersonic flights ars more common during air combat maneuvers. Most of the existing data on focus booms are related to high-speed civil operations such as transitional linear accelerations and mild turns. However, military aircraft operating in training areas perform more drastic maneuvers such as dives and high-g turns. An update and confirmation of USAF prediction capabilities is required to demonstrate the ability to predict and control sonic boom impacts, especially those produced by air combat maneuvers.

  15. Numerical Predictions of Sonic Boom Signatures for a Straight Line Segmented Leading Edge Model

    Science.gov (United States)

    Elmiligui, Alaa A.; Wilcox, Floyd J.; Cliff, Susan; Thomas, Scott

    2012-01-01

    A sonic boom wind tunnel test was conducted on a straight-line segmented leading edge (SLSLE) model in the NASA Langley 4- by 4- Foot Unitary Plan Wind Tunnel (UPWT). The purpose of the test was to determine whether accurate sonic boom measurements could be obtained while continuously moving the SLSLE model past a conical pressure probe. Sonic boom signatures were also obtained using the conventional move-pause data acquisition method for comparison. The continuous data acquisition approach allows for accurate signatures approximately 15 times faster than a move-pause technique. These successful results provide an incentive for future testing with greatly increased efficiency using the continuous model translation technique with the single probe to measure sonic boom signatures. Two widely used NASA codes, USM3D (Navier-Stokes) and CART3D-AERO (Euler, adjoint-based adaptive mesh), were used to compute off-body sonic boom pressure signatures of the SLSLE model at several different altitudes below the model at Mach 2.0. The computed pressure signatures compared well with wind tunnel data. The effect of the different altitude for signature extraction was evaluated by extrapolating the near field signatures to the ground and comparing pressure signatures and sonic boom loudness levels.

  16. Focused and Steady-State Characteristics of Shaped Sonic Boom Signatures: Prediction and Analysis

    Science.gov (United States)

    Maglieri, Domenic J.; Bobbitt, Percy J.; Massey, Steven J.; Plotkin, Kenneth J.; Kandil, Osama A.; Zheng, Xudong

    2011-01-01

    The objective of this study is to examine the effect of flight, at off-design conditions, on the propagated sonic boom pressure signatures of a small "low-boom" supersonic aircraft. The amplification, or focusing, of the low magnitude "shaped" signatures produced by maneuvers such as the accelerations from transonic to supersonic speeds, climbs, turns, pull-up and pushovers is the concern. To analyze these effects, new and/or improved theoretical tools have been developed, in addition to the use of existing methodology. Several shaped signatures are considered in the application of these tools to the study of selected maneuvers and off-design conditions. The results of these applications are reported in this paper as well as the details of the new analytical tools. Finally, the magnitude of the focused boom problem for "low boom" supersonic aircraft designs has been more accurately quantified and potential "mitigations" suggested. In general, "shaped boom" signatures, designed for cruise flight, such as asymmetric and symmetric flat-top and initial-shock ramp waveforms retain their basic shape during transition flight. Complex and asymmetric and symmetric initial shock ramp waveforms provide lower magnitude focus boom levels than N-waves or asymmetric and symmetric flat-top signatures.

  17. SCAMP: Rapid Focused Sonic Boom Waypoint Flight Planning Methods, Execution, and Results

    Science.gov (United States)

    Haering, Edward A., Jr.; Cliatt, Larry J., II; Delaney, Michael M., Jr.; Plotkin, Kenneth J.; Maglieri, Domenic J.; Brown, Jacob C.

    2012-01-01

    Successful execution of the flight phase of the Superboom Caustic Analysis and Measurement Project (SCAMP) required accurate placement of focused sonic booms on an array of prepositioned ground sensors. While the array was spread over a 10,000-ft-long area, this is a relatively small region when considering the speed of a supersonic aircraft and sonic boom ray path variability due to shifting atmospheric conditions and aircraft trajectories. Another requirement of the project was to determine the proper position for a microphone-equipped motorized glider to intercept the sonic boom caustic, adding critical timing to the constraints. Variability in several inputs to these calculations caused some shifts of the focus away from the optimal location. Reports of the sonic booms heard by persons positioned amongst the array were used to shift the focus closer to the optimal location for subsequent passes. This paper describes the methods and computations used to place the focused sonic boom on the SCAMP array and gives recommendations for their accurate placement by future quiet supersonic aircraft. For the SCAMP flights, 67% of the foci were placed on the ground array with measured positions within a few thousand feet of computed positions. Among those foci with large caustic elevation angles, 96% of foci were placed on the array, and measured positions were within a few hundred feet of computed positions. The motorized glider captured sonic booms on 59% of the passes when the instrumentation was operating properly.

  18. High-Speed Research: 1994 Sonic Boom Workshop. Configuration, Design, Analysis and Testing

    Science.gov (United States)

    McCurdy, David A. (Editor)

    1999-01-01

    The third High-Speed Research Sonic Boom Workshop was held at NASA Langley Research Center on June 1-3, 1994. The purpose of this workshop was to provide a forum for Government, industry, and university participants to present and discuss progress in their research. The workshop was organized into sessions dealing with atmospheric propagation; acceptability studies; and configuration design, and testing. Attendance at the workshop was by invitation only. The workshop proceedings include papers on design, analysis, and testing of low-boom high-speed civil transport configurations and experimental techniques for measuring sonic booms. Significant progress is noted in these areas in the time since the previous workshop a year earlier. The papers include preliminary results of sonic boom wind tunnel tests conducted during 1993 and 1994 on several low-boom designs. Results of a mission performance analysis of all low-boom designs are also included. Two experimental methods for measuring near-field signatures of airplanes in flight are reported.

  19. Circuits of Memory: The War Memory Boom in Western Australia

    Directory of Open Access Journals (Sweden)

    John R. Stephens

    2012-08-01

    Full Text Available In some Australian academic circles in the 1980s it was believed that, as the numbers of soldiers of the world wars declined over time, so would attendances at war remembrance ceremonies on Anzac Day and interest in war commemoration in general. Contrary to expectation, however, there has been a steady rise in eagerness for war memory in Australia over the past three decades manifest in media interest and increasing attendance at Anzac Day services. Rather than dying out, ‘Anzac’ is being reinvented for new generations. Emerging from this phenomenon has been a concomitant rise in war memorial and commemorative landscape building across Australia fuelled by government funding (mostly federal and our relentless search for a national story. Many more memorial landscapes have been built in Western Australia over the past thirty years than at the end of either of the World Wars, a trend set to peak in 2014 with the Centenary of Anzac. This paper examines the origins and progress of this boom in memorial building in Western Australia and argues that these new memorial settings establish ‘circuits of memory’ which ultimately re-enchant and reinforce the Anzac renaissance.

  20. Boom, Bust and Beyond: Arts and Sustainability in Calumet, Michigan

    Directory of Open Access Journals (Sweden)

    Richelle Winkler

    2016-03-01

    Full Text Available Cycles of boom and bust plague mining communities around the globe, and decades after the bust the skeletons of shrunken cities remain. This article evaluates strategies for how former mining communities cope and strive for sustainability in the decades well beyond the bust, using a case study of Calumet, Michigan. In 1910, Calumet was at the center of the mining industry in the Upper Peninsula of Michigan, but in the century since its peak, mining employment steadily declined until the last mine closed in 1968, and the population declined by over 80%. This paper explores challenges, opportunities, and progress toward sustainability associated with arts-related development in this context. Methods are mixed, including observation, interviews, document review, a survey, and secondary data analysis. We follow Flora and Flora’s Community Capitals Framework to analyze progress toward sustainability. Despite key challenges associated with the shrunken city context (degraded tax base, overbuilt and aging infrastructure, diminished human capital, and a rather limited set of volunteers and political actors, we find the shrunken city also offers advantages for arts development, including low rents, less risk of gentrification, access to space, and political incentive. In Calumet, we see evidence of a spiraling up pattern toward social sustainability resulting from arts development; however impacts on environmental and economic sustainability are limited.

  1. Performance of a Supersonic Over-Wing Inlet with Application to a Low-Sonic-Boom Aircraft

    Science.gov (United States)

    Trefny, Charles J.; Hirt, Stefanie M.; Anderson, Bernhard H.; Fink, Lawrence E.; Magee, Todd E.

    2014-01-01

    Development of commercial supersonic aircraft has been hindered by many related factors including fuel-efficiency, economics, and sonic-boom signatures that have prevented over-land flight. Materials, propulsion, and flight control technologies have developed to the point where, if over-land flight were made possible, a commercial supersonic transport could be economically viable. Computational fluid dynamics, and modern optimization techniques enable designers to reduce the boom signature of candidate aircraft configurations to acceptable levels. However, propulsion systems must be carefully integrated with these low-boom configurations in order that the signatures remain acceptable. One technique to minimize the downward propagation of waves is to mount the propulsion systems above the wing, such that the wing provides shielding from shock waves generated by the inlet and nacelle. This topmounted approach introduces a number of issues with inlet design and performance especially with the highly-swept wing configurations common to low-boom designs. A 1.79%-scale aircraft model was built and tested at the NASA Glenn Research Center's 8-by 6-Foot Supersonic Wind Tunnel (8x6 SWT) to validate the configuration's sonic boom signature. In order to evaluate performance of the top-mounted inlets, the starboard flow-through nacelle on the aerodynamic model was replaced by a 2.3%-scale operational inlet model. This integrated configuration was tested at the 8x6 SWT from Mach 0.25 to 1.8 over a wide range of angles-of-attack and yaw. The inlet was also tested in an isolated configuration over a smaller range of angles-of-attack and yaw. A number of boundary-layer bleed configurations were investigated and found to provide a substantial positive impact on pressure recovery and distortion. Installed inlet performance in terms of mass capture, pressure recovery, and distortion over the Mach number range at the design angle-of-attack of 4-degrees is presented herein and compared

  2. A Flight Research Overview of WSPR, a Pilot Project for Sonic Boom Community Response

    Science.gov (United States)

    Cliatt, Larry J., II; Haering, Edward A., Jr.; Jones, Thomas P.; Waggoner, Erin R.; Flattery, Ashley K.; Wiley, Scott L.

    2014-01-01

    In support of the ongoing effort by the National Aeronautics and Space Administration (NASA) to bring supersonic commercial travel to the public, the NASA Armstrong Flight Research Center and the NASA Langley Research Center, in cooperation with other industry organizations, conducted a flight research experiment to identify the methods, tools, and best practices for a large-scale quiet (or low) sonic boom community human response test. The name of the effort was Waveforms and Sonic boom Perception and Response (WSPR). Such tests will be applied to building a dataset that governing agencies such as the Federal Aviation Administration and the International Civil Aviation Organization will use to establish regulations for acceptable sound levels of overland sonic booms. The WSPR test was the first such effort that studied responses to non-traditional low sonic booms while the subject persons were in their own homes and performing daily activities.The WSPR test was a NASA collaborative effort with several industry partners, in response to a NASA Aeronautics Research Mission Directorate Research Opportunities in Aeronautics. The primary contractor was Wyle (El Segundo, California). Other partners included Gulfstream Aerospace Corporation (Savannah, Georgia); Pennsylvania State University (University Park, Pennsylvania); Tetra Tech, Inc. (Pasadena, California); and Fidell Associates, Inc. (Woodland Hills, California).A major objective of the effort included exposing a community to the sonic boom magnitudes and occurrences that would be expected to occur in high-air traffic regions having a network of supersonic commercial aircraft in place. Low-level sonic booms designed to simulate those produced by the next generation of commercial supersonic aircraft were generated over a small residential community. The sonic boom footprint was recorded with an autonomous wireless microphone array that spanned the entire community. Human response data were collected using multiple

  3. Using FUN3D for Aeroelastic, Sonic Boom, and AeroPropulsoServoElastic (APSE) Analyses of a Supersonic Configuration

    Science.gov (United States)

    Silva, Walter A.; Sanetrik, Mark D.; Chwalowski, Pawel; Connolly, Joseph; Kopasakis, George

    2016-01-01

    An overview of recent applications of the FUN3D CFD code to computational aeroelastic, sonic boom, and aeropropulsoservoelasticity (APSE) analyses of a low-boom supersonic configuration is presented. The overview includes details of the computational models developed including multiple unstructured CFD grids suitable for aeroelastic and sonic boom analyses. In addition, aeroelastic Reduced-Order Models (ROMs) are generated and used to rapidly compute the aeroelastic response and utter boundaries at multiple flight conditions.

  4. The geochemical behaviour of selenium in the Boom Clay system - a XANES and EXAFS study

    International Nuclear Information System (INIS)

    2S, KULeuven, B-3001Leuven (Belgium))" data-affiliation=" (Center for surface Chemistry and Catalysis - M2S, KULeuven, B-3001Leuven (Belgium))" >Breynaert, Eric; 2S, KULeuven, B-3001Leuven (Belgium))" data-affiliation=" (Center for surface Chemistry and Catalysis - M2S, KULeuven, B-3001Leuven (Belgium))" >Dom, Dirk; 2S, KULeuven, B-3001Leuven (Belgium))" data-affiliation=" (Center for surface Chemistry and Catalysis - M2S, KULeuven, B-3001Leuven (Belgium))" >Vancluysen, Jacqueline; 2S, KULeuven, B-3001Leuven (Belgium))" data-affiliation=" (Center for surface Chemistry and Catalysis - M2S, KULeuven, B-3001Leuven (Belgium))" >Kirschhock, Christine E.A.; 2S, KULeuven, B-3001Leuven (Belgium))" data-affiliation=" (Center for surface Chemistry and Catalysis - M2S, KULeuven, B-3001Leuven (Belgium))" >Maes, Andre; Scheinost, Andreas C.

    2010-01-01

    Document available in extended abstract form only. In Belgium, the Boom Clay formation is studied as a reference host formation for the geological disposal of high-level and long-lived radioactive waste for more than 30 years. This formation mainly consists of mixed clay minerals (illite, inter-stratified illite-smectite), pyrite and immobile and dissolved natural organic matter. Since it provides good sorption capacities, very low permeability, and chemically reducing conditions due to the presence of pyrite (FeS 2 ), the Boom clay formation itself is considered to be the main barrier preventing radionuclide migration from the geological repository. Within this concept for geological storage Se 79 has been identified as one of the critical elements contributing to the final dose to man. Although the sorption and migration behaviour of Se in the Boom Clay system has been thoroughly studied, the speciation of Se in the Boom Clay system has never been identified spectroscopically. In all previous studies, the interpretation of the behaviour of Se in Boom Clay conditions has always been based on circumstantial evidence such as solubility measurements or comparison with the spectroscopically identified speciation of Se in model systems. Based on the XANES analysis, selenite is transformed into Se 0 confirming the previously proposed reduction of selenite in the Boom Clay system. Combination of the mass-balance for Se with the results from linear combination analysis of the XANES spectra provided new evidence for the sorption-reduction mechanism proposed to explain the interaction between Se(IV) and the BC solid phase. In addition, evidence was found that that the fate of Se(IV) in the BC system is completely dominated by its interaction with pyrite present in the Boom Clay. The combined EXAFS analysis of Se in Se 0 reference phases (hexagonal, monoclinic, Se-loaded pyrite) allowed to elucidate further details on the short-range structure of the reaction products formed

  5. A study of the flexible body dynamics of the RAE-A satellite

    Science.gov (United States)

    1971-01-01

    Spacecraft flight data was compared with simulated data computed by the RAE and IMP dynamics simulator computer programs. There was not sufficient data available to provide definitive data on antenna boom position to the Radio Astronomy experimenter. There was, however, enough data to indicate the trend of antenna boom stiffness and temperature gradient. It was possible to obtain a good fit of simulated data to measured spacecraft attitude data when the antenna booms were extended to 450 feet. The value of the RAE-A antenna boom stiffness appears to be significantly less than the preflight ground measured value. It was confirmed that an improved simulation can be obtained by using values of the root angles of the antenna booms and by using an angle of the damper plane of motion, relative to the plane of the antennas, which differed from preflight ground measurements.

  6. Transport of dissolved organic matter in Boom Clay: Size effects

    Science.gov (United States)

    Durce, D.; Aertsens, M.; Jacques, D.; Maes, N.; Van Gompel, M.

    2018-01-01

    A coupled experimental-modelling approach was developed to evaluate the effects of molecular weight (MW) of dissolved organic matter (DOM) on its transport through intact Boom Clay (BC) samples. Natural DOM was sampled in-situ in the BC layer. Transport was investigated with percolation experiments on 1.5 cm BC samples by measuring the outflow MW distribution (MWD) by size exclusion chromatography (SEC). A one-dimensional reactive transport model was developed to account for retardation, diffusion and entrapment (attachment and/or straining) of DOM. These parameters were determined along the MWD by implementing a discretisation of DOM into several MW points and modelling the breakthrough of each point. The pore throat diameter of BC was determined as 6.6-7.6 nm. Below this critical size, transport of DOM is MW dependent and two major types of transport were identified. Below MW of 2 kDa, DOM was neither strongly trapped nor strongly retarded. This fraction had an averaged capacity factor of 1.19 ± 0.24 and an apparent dispersion coefficient ranging from 7.5 × 10- 11 to 1.7 × 10- 11 m2/s with increasing MW. DOM with MW > 2 kDa was affected by both retardation and straining that increased significantly with increasing MW while apparent dispersion coefficients decreased. Values ranging from 1.36 to 19.6 were determined for the capacity factor and 3.2 × 10- 11 to 1.0 × 10- 11 m2/s for the apparent dispersion coefficient for species with 2.2 kDa < MW < 9.3 kDa. Straining resulted in an immobilisation of in average 49 ± 6% of the injected 9.3 kDa species. Our findings show that an accurate description of DOM transport requires the consideration of the size effects.

  7. Laboratory hydro-mechanical characterisation of Boom Clay at Essen and Mol

    International Nuclear Information System (INIS)

    Deng, Y. F.; Tang, A. M.; Cui, Y. J.; Nguyen, X. P.; Li, X. L.; Wouters, L.

    2011-01-01

    Boom Clay has been selected as a potential host rock formation for the geological disposal of radioactive waste in Belgium. In the present work, the hydro-mechanical behaviour of Boom Clay samples from the borehole Essen-1 at a depth of 220-260 m and from HADES that is the underground rock laboratory at Mol in Belgium, at 223-m depth was investigated in the laboratory by performing low pressure odometer tests (vertical effective stress ranging from 0.05 to 3.2 MPa), high pressure odometer tests (vertical effective stress ranging from 0.125 to 32 MPa), isotropic consolidation tests (confining effective stress ranging from the in situ stress to 20 MPa) and triaxial shear tests. It has been observed that the mineralogy, geotechnical properties and hydro-mechanical behaviour of Boom Clay from Essen at 227-m, 240-m and 248-m depths are similar to that of Boom Clay from Mol. As in the case of Boom Clay at Mol, the failure envelope of Boom Clay at Essen in the p'- q plane is not linear. The slope of the portion beyond the pre-consolidation stress of Boom Clay from Essen is almost the same as that from Mol, suggesting a similar internal friction angle of about 13 deg. The compression curves (void index I v versus logarithm of vertical stress) beyond the pre-consolidation stress are the same for both samples from Mol and Essen, and situated between the intrinsic compression line (ICL) and the sedimentation compression line (SCL). The yield stress determined from odometer tests seems to be stress-path dependent and lower than the pre-consolidation stress. Thus determining the over-consolidation ratio (OCR) using the yield stress value would lead to an incorrect estimate. From a practical point view, the laboratory test results from Essen and their comparison with those from Mol provide important information regarding the transferability of knowledge on Boom Clay at different sites, taking into account the fact that most investigations have been carried out on Boom Clay at

  8. Sonic Booms in Atmospheric Turbulence (SonicBAT) Ground Measurements in a Hot Desert Climate

    Science.gov (United States)

    Haering, Edward A., Jr.

    2017-01-01

    The Sonic Booms in Atmospheric Turbulence (SonicBAT) Project flew a series of 20 F-18 flights with 69 supersonic passes at Edwards Air Force Base in July 2016 to quantify the effect of atmospheric turbulence on sonic booms. Most of the passes were at a pressure altitude of 32,000 feet and a Mach number of 1.4, yielding a nominal sonic boom overpressure of 1.6 pounds per square foot. Atmospheric sensors such as GPS sondeballoons, Sonic Detection and Ranging (SODAR) acoustic sounders, and ultrasonic anemometers were used to characterize the turbulence state of the atmosphere for each flight. Spiked signatures in excess of 7 pounds per square foot were measured at some locations, as well as rounded sonic-boom signatures with levels much lower than the nominal. This presentation will quantify the range of overpressure and Perceived Level of the sonic boom as a function of turbulence parameters, and also present the spatial variation of these quantities over the array. Comparison with historical data will also be shown.

  9. The NET articulated boom: Preliminary investigations and justification for a full scale prototype

    International Nuclear Information System (INIS)

    Suppan, A.

    1990-12-01

    The articulated boom system is the favourite in-vessel handling system for NET which will be used to maintain or replace in-vessel components during short term interventions. The testbed EDITH is the prototype of this system and is the logical step between the proof of principle of the system, which is already performed by the JET articulated boom, and the operational equipment for NET. EDITH is required to demonstrate that maintenance of plasma facing components can be carried out with the anticipated reliability and time. To achieve this aim EDITH is based on the experience of the JET boom and will be constructed in full scale, supplemented by a full scale mock-up. A further goal of EDITH is to allow the testing of boom components and subassemblies. The results of preliminary investigations for the boom are summarized, the need of the testbed EDITH and a full scale mock-up is discussed and both EDITH and the mock-up are described. (orig.) [de

  10. Prevalence and factors associated with percutaneous injuries and splash exposures among health-care workers in a provincial hospital, Kenya, 2010

    Science.gov (United States)

    Mbaisi, Everline Muhonja; Ng'ang'a, Zipporah; Wanzala, Peter; Omolo, Jared

    2013-01-01

    Introduction Accidental occupational exposure of healthcare workers to blood and body fluids after skin injury or mucous membrane contact constitutes a risk for transmission of blood-borne pathogens. Such pathogens include Human Immunodeficiency Virus (HIV), Hepatitis B virus (HBV) and Hepatitis C virus (HCV). We conducted a study to determine the prevalence and associated factors for percutaneous injuries and splash exposures among health-care workers in Rift Valley provincial hospital. Methods A cross-sectional study was carried out from October to November 2010. Self reported incidents, circumstances surrounding occupational exposure and post-exposure management were sought by use of interviewer administered questionnaire. Descriptive, bivariate and multiple logistic regression (forward stepwise procedure) analyses were performed. The level of significance was set at 0.05. Results Twenty five percent of health-care workers interviewed (N = 305) reported having been exposed to blood and body fluids in the preceding 12 months. Percutaneous injuries were reported by 19% (n = 305) and splash to mucous membrane by 7.2%. Higher rates of percutaneous injuries were observed among nurses (50%), during stitching (30%), and in obstetric and gynecologic department (22%). Health workers aged below 40 years were more likely to experience percutaneous injuries (OR= 3.7; 95% CI = 1.08-9.13) while previous training in infection prevention was protective (OR= 0.52; 95% CI = 0.03-0.90). Forty eight percent (n = 83) reported the incidents with 20% (n = 83) taking PEP against HIV. Conclusion Percutaneous injuries and splashes are common in Rift Valley Provincial hospital. Preventive measures remain inadequate. Health institutions should have policies, institute surveillance for occupational risks and enhance training of health care workers. PMID:23504245

  11. Effectiveness of a Wedge Probe to Measure Sonic Boom Signatures in a Supersonic Wind Tunnel

    Science.gov (United States)

    Wilcox, Floyd J., Jr.; Elmiligui, Alaa A.

    2013-01-01

    A wind tunnel investigation was conducted in the Langley Unitary Plan Wind Tunnel (UPWT) to determine the effectiveness of a wedge probe to measure sonic boom pressure signatures compared to a slender conical probe. A generic business jet model at a constant angle of attack and at a single model to probe separation distance was used to generate a sonic boom signature. Pressure signature data were acquired with both the wedge probe and a slender conical probe for comparison. The test was conducted at a Mach number of 2.0 and a free-stream unit Reynolds number of 2 million per foot. The results showed that the wedge probe was not effective in measuring the sonic boom pressure signature of the aircraft model in the supersonic wind tunnel. Data plots and a discussion of the results are presented. No tabulated data or flow visualization photographs are included.

  12. Application of Adjoint Methodology in Various Aspects of Sonic Boom Design

    Science.gov (United States)

    Rallabhandi, Sriram K.

    2014-01-01

    One of the advances in computational design has been the development of adjoint methods allowing efficient calculation of sensitivities in gradient-based shape optimization. This paper discusses two new applications of adjoint methodology that have been developed to aid in sonic boom mitigation exercises. In the first, equivalent area targets are generated using adjoint sensitivities of selected boom metrics. These targets may then be used to drive the vehicle shape during optimization. The second application is the computation of adjoint sensitivities of boom metrics on the ground with respect to parameters such as flight conditions, propagation sampling rate, and selected inputs to the propagation algorithms. These sensitivities enable the designer to make more informed selections of flight conditions at which the chosen cost functionals are less sensitive.

  13. Sheath-Based Rollable Lenticular-Shaped and Low-Stiction Composite Boom

    Science.gov (United States)

    Fernandez, Juan M. (Inventor)

    2018-01-01

    Various embodiments provide rollable and deployable composite booms that may be used in a wide range of applications both for space and terrestrial structural solutions. Various embodiment composite booms may be bistable, i.e. having a stable strain energy minimum in the coiled configuration as well as the in the deployed configuration. In various embodiments, a boom may be fabricated by aligning two independent tape-springs front-to-front encircled by a durable seamless polymer sleeve. The durable seamless polymer sleeve may allow the two tape-springs to slide past each other during the coiling/deployment process so as to reduce, e.g., minimize, shear and its derived problems.

  14. The Iron Law of Financial Markets: Self-fulfilling Prophecies and Speculative Booms and Busts

    Directory of Open Access Journals (Sweden)

    Ognjen Radonjić

    2016-02-01

    Full Text Available This paper discusses the factors which, in the absence of strong financial regulation, sustain the Iron Law of the Financial Markets asserting that speculative booms and busts occur more or less regularly from 17 century to the present. The first factor is that financial markets are self-fulfilling system. The second is that human nature does not change and is based on egoism, materialism, loss aversion, exaggerated hopes and fears, emulation, propensity to gamble, herd behavior and so on. Lastly, there is the extreme brevity of the financial memory. In order to enable economic authorities and/or individuals to detect timely that the unsustainable boom is under the way, we have identified the common features of historically recorded speculative episodes. Stages through which the system passes on its way from unsustainable rise to inevitable fall are: displacement, boom, overtrading, financial distress and discredit or revulsion.

  15. Simulation and controller design for an agricultural sprayer boom leveling system

    KAUST Repository

    Sun, Jian

    2011-01-01

    According to the agricultural precision requirements, the distance from sprayer nozzles to the corps should be kept between 50 cm to 70 cm. The sprayer boom also needs to be kept parallel to the field during the operation process. Thus we can guarantee the quality of the chemical droplets distribution on the crops. In this paper we introduced a sprayer boom leveling system for agricultural sprayer vehicles with electro-hydraulic auto-leveling system. The suitable hydraulic actuating cylinder and valve were selected according to the specific systemic specifications. Furthermore, a compensation controller for the electro-hydraulic system was designed based on the mathematical model. With simulations we can optimize the performance of this controller to make sure a fast leveling response to the inclined sprayer boom. © 2011 IEEE.

  16. Pilot Test of a Novel Method for Assessing Community Response to Low-Amplitude Sonic Booms

    Science.gov (United States)

    Fidell, Sanford; Horonjeff, Richard D.; Harris, Michael

    2012-01-01

    A pilot test of a novel method for assessing residents annoyance to sonic booms was performed. During a two-week period, residents of the base housing area at Edwards Air Force Base provided data on their reactions to sonic booms using Smartphone-based interviews. Noise measurements were conducted at the same time. The report presents information about data collection methods and about test participants reactions to low-amplitude sonic booms. The latter information should not be viewed as definitive for several reasons. It may not be reliably generalized to the wider U.S. residential population (because it was not derived from a representative random sample) and the sample itself was not large.

  17. Understanding the expansion of energy crops beyond the global biofuel boom : evidence from oil palm expansion in Colombia

    NARCIS (Netherlands)

    Marin-Burgos, Victoria; Clancy, Joy S.

    2017-01-01

    Background: The global palm oil market experienced a remarkable boom since the year 2000. Since palm oil can be used for biodiesel production, the global expansion of oil palm cultivation has been associated with the global biofuel boom. Biofuel policies—especially those adopted in the European

  18. Modification of sonic boom wave forms during propagation from the source to the ground.

    Science.gov (United States)

    Bass, Henry E; Raspet, Richard; Chambers, James P; Kelly, Mark

    2002-01-01

    A number of physical processes work to modify the shape of sonic boom wave forms as the wave form propagates from the aircraft to a receiver on the ground. These include frequency-dependent absorption, nonlinear steepening, and scattering by atmospheric turbulence. In the past two decades, each of these effects has been introduced into numerical prediction algorithms and results compared to experimental measurements. There is still some disagreement between measurements and prediction, but those differences are now in the range of tens of percent. The processes seem to be understood. The present understanding of sonic boom evolution will be presented along with experimental justification.

  19. Étude du comportement anisotrope de l'argile de Boom

    OpenAIRE

    Dao, Linh Quyen

    2015-01-01

    In the program of deep geological radioactive waste disposal in Belgium, Boom Clay has been chosen as one of the potential host rocks. Due to the geological stratification, this stiff clay has been regarded as a transverse isotropic material. The anisotropy of its hydraulic and thermal properties was shown in several studies. It seems necessary now to conduct a more in-depth study on the anisotropic behaviour of Boom Clay. In terms of experimental works, the anisotropy of the thermo-hydro-mec...

  20. Design of Rail Instrumentation for Wind Tunnel Sonic Boom Measurements and Computational-Experimental Comparisons

    Science.gov (United States)

    Cliff, Susan E.; Elmiligui, A.; Aftosmis, M.; Morgenstern, J.; Durston, D.; Thomas, S.

    2012-01-01

    An innovative pressure rail concept for wind tunnel sonic boom testing of modern aircraft configurations with very low overpressures was designed with an adjoint-based solution-adapted Cartesian grid method. The computational method requires accurate free-air calculations of a test article as well as solutions modeling the influence of rail and tunnel walls. Specialized grids for accurate Euler and Navier-Stokes sonic boom computations were used on several test articles including complete aircraft models with flow-through nacelles. The computed pressure signatures are compared with recent results from the NASA 9- x 7-foot Supersonic Wind Tunnel using the advanced rail design.

  1. Parallel Splash Belief Propagation

    Science.gov (United States)

    2010-08-01

    Service, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of...heaps: An alternative to Fibonacci heaps with applications to parallel computation. Communications of the ACM, 31:1343–1354, 1988. G. Elidan, I. Mcgraw

  2. Characterization of the wine boom in Mendoza (Argentina, 1904-1912 Caracterización del boom vitivinícola en Mendoza (Argentina, 1904-1912

    Directory of Open Access Journals (Sweden)

    Patricia Barrio de Villanueva

    2009-01-01

    Full Text Available Mendocinean viticulture experimented between 1904 and 1912 a booming economical growth consistent with the national average growth. In this article we present the values of some variables that illustrate some representative indicators of that section of the economy. We attempt to reconstruct the production costs of grapes and wines and the possible revenues of the viticulture actorsEn consonancia con el ritmo de crecimiento de la economía nacional, la vitivinicultura mendocina vivió, entre 1904 y 1912, un verdadero boom económico-productivo. En este artículo se presenta información de dicho fenómeno a través de algunas variables representativas del sector. En segundo lugar, se intenta reconstruir los costos de producción de uva y vino, y la probable rentabilidad de los actores vitivinícolas

  3. Migrant labor supply in a booming non-renewable resource economy: Cure and transmission mechanism for de-industrialization?

    Science.gov (United States)

    Nulle, Grant Mark

    This paper challenges the determinism that booming resource economies suffer from de-industrialization, the "Dutch Disease". For several decades, economists have attempted to explain how a sudden surge in mineral and energy extraction affects an economy's output and employment from an aggregate and sectoral perspective. Economic theory shows that a "boom" in mineral and energy production is welfare enhancing to the economy experiencing it. However, the phenomenon also induces inter-sectoral adjustments among non-renewable resource (NRR), traditional traded, and non-traded industries that tend to crowd out traditional export sectors such as agriculture and manufacturing. In turn, this paper asks two fundamental questions: 1) Can the inter-sectoral adjustments wrought by a boom in NRR production be mitigated in the resource-abundant economy experiencing it; 2) Can the inter-sectoral adjustments be exported to a neighboring non-resource economy by movements in migrant labor supply? The theoretical model and empirical estimation approach presented in this paper introduces an endogenous migrant labor supply response to booms in NRR output to test the extent traditional tradable sectors shrink in the NRR-abundant economy during the boom and if such effects are exported to a neighboring jurisdiction. Using data at the U.S. county level, the empirical results show that booming economies experience positive and statistically significant rates of real income and traded sector job growth during the boom, attributable to the influx of migrant labor. By contrast, little evidence is found that non-booming counties adjacent to the booming counties experience declines in income or job growth because of labor supply outflows. Instead, the results suggest the larger the number of potential "donor" counties that can supply labor to the booming economies, the more likely the transmission of booming economy effects, namely evidence of de-industrialization, is diffused across all of the

  4. Experimental Measurements of Sonic Boom Signatures Using a Continuous Data Acquisition Technique

    Science.gov (United States)

    Wilcox, Floyd J.; Elmiligui, Alaa A.

    2013-01-01

    A wind tunnel investigation was conducted in the Langley Unitary Plan Wind Tunnel to determine the effectiveness of a technique to measure aircraft sonic boom signatures using a single conical survey probe while continuously moving the model past the probe. Sonic boom signatures were obtained using both move-pause and continuous data acquisition methods for comparison. The test was conducted using a generic business jet model at a constant angle of attack and a single model-to-survey-probe separation distance. The sonic boom signatures were obtained at a Mach number of 2.0 and a unit Reynolds number of 2 million per foot. The test results showed that it is possible to obtain sonic boom signatures while continuously moving the model and that the time required to acquire the signature is at least 10 times faster than the move-pause method. Data plots are presented with a discussion of the results. No tabulated data or flow visualization photographs are included.

  5. The effects of simulated sonic booms on tracking performance and autonomic response.

    Science.gov (United States)

    1971-06-01

    Subjects were exposed to four simulated 'indoor' sonic booms over an approximate thirty-minute period. The overpressure levels were 1.0, 2.0 and 4.0 psf (as measured 'outdoors') with durations of 295 milliseconds. Subjects performed a two-dimensional...

  6. A comparison of the startle effects resulting from exposure to two levels of simulated sonic booms.

    Science.gov (United States)

    1973-12-01

    Subjects were exposed indoors to simulated sonic booms having outside overpressures of 50 and 150 N/sq m. Rise times were held constant at 5.5 msecs. In addition to the outside measurements, inside measures of dBlin and dBA were also obtained. Subjec...

  7. Cart3D Analysis of Plume and Shock Interaction Effects on Sonic Boom

    Science.gov (United States)

    Castner, Raymond

    2015-01-01

    A plume and shock interaction study was developed to collect data and perform CFD on a configuration where a nozzle plume passed through the shock generated from the wing or tail of a supersonic vehicle. The wing or tail was simulated with a wedge-shaped shock generator. Three configurations were analyzed consisting of two strut mounted wedges and one propulsion pod with an aft deck from a low boom vehicle concept. Research efforts at NASA were intended to enable future supersonic flight over land in the United States. Two of these efforts provided data for regulatory change and enabled design of low boom aircraft. Research has determined that sonic boom is a function of aircraft lift and volume distribution. Through careful tailoring of these variables, the sonic boom of concept vehicles has been reduced. One aspect of vehicle tailoring involved how the aircraft engine exhaust interacted with aft surfaces on a supersonic aircraft, such as the tail and wing trailing edges. In this work, results from Euler CFD simulations are compared to experimental data collected on sub-scale components in a wind tunnel. Three configurations are studied to simulate the nozzle plume interaction with representative wing and tail surfaces. Results demonstrate how the plume and tail shock structure moves with increasing nozzle pressure ratio. The CFD captures the main features of the plume and shock interaction. Differences are observed in the plume and deck shock structure that warrant further research and investigation.

  8. Simulator Study of Indoor Annoyance Caused by Shaped Sonic Boom Stimuli With and Without Rattle Augmentation

    Science.gov (United States)

    Rathsam, Jonathan; Loubeau, Alexandra; Klos, Jacob

    2013-01-01

    The National Aeronautics and Space Administration's High Speed Project is developing a predictive capability for annoyance caused by shaped sonic booms transmitted indoors. The predictive capability is intended for use by aircraft designers as well as by aircraft noise regulators who are considering lifting the current prohibition on overland civil supersonic flight. The goal of the current study is to use an indoor simulator to validate two models developed using headphone tests for annoyance caused by sonic booms with and without rattle augmentation. The predictors in the proposed models include Moore and Glasberg's Stationary Loudness Level, the time derivative of Moore and Glasberg's time-varying short-term Loudness Level, and the difference between two weighted sound exposure levels, CSEL-ASEL. The indoor simulator provides a more realistic listening environment than headphones due to lowfrequency sound reproduction down to 6 Hz, which also causes perceptible tactile vibration. The results of this study show that a model consisting of {PL + (CSEL-ASEL)} is a reliable predictor of annoyance caused by shaped sonic booms alone, rattle sounds alone, and shaped sonic booms and rattle sounds together.

  9. Numerical simulation of shock wave focusing at fold caustics, with application to sonic boom.

    Science.gov (United States)

    Marchiano, Régis; Coulouvrat, François; Grenon, Richard

    2003-10-01

    Weak shock wave focusing at fold caustics is described by the mixed type elliptic/hyperbolic nonlinear Tricomi equation. This paper presents a new and original numerical method for solving this equation, using a potential formulation and an "exact" numerical solver for handling nonlinearities. Validation tests demonstrate quantitatively the efficiency of the algorithm, which is able to handle complex waveforms as may come out from "optimized" aircraft designed to minimize sonic booms. It provides a real alternative to the approximate method of the hodograph transform. This motivated the application to evaluate the ground track focusing of sonic boom for an accelerating aircraft, by coupling CFD Euler simulations performed around the mock-up on an adaptated mesh grid, atmospheric propagation modeling, and the Tricomi algorithm. The chosen configuration is the European Eurosup mock-up. Convergence of the focused boom at the ground level as a function of the matching distance is investigated to demonstrate the efficiency of the numerical process. As a conclusion, it is indicated how the present work may pave the way towards a study on sonic superboom (focused boom) mitigation.

  10. Cart3D Simulations for the Second AIAA Sonic Boom Prediction Workshop

    Science.gov (United States)

    Anderson, George R.; Aftosmis, Michael J.; Nemec, Marian

    2017-01-01

    Simulation results are presented for all test cases prescribed in the Second AIAA Sonic Boom Prediction Workshop. For each of the four nearfield test cases, we compute pressure signatures at specified distances and off-track angles, using an inviscid, embedded-boundary Cartesian-mesh flow solver with output-based mesh adaptation. The cases range in complexity from an axisymmetric body to a full low-boom aircraft configuration with a powered nacelle. For efficiency, boom carpets are decomposed into sets of independent meshes and computed in parallel. This also facilitates the use of more effective meshing strategies - each off-track angle is computed on a mesh with good azimuthal alignment, higher aspect ratio cells, and more tailored adaptation. The nearfield signatures generally exhibit good convergence with mesh refinement. We introduce a local error estimation procedure to highlight regions of the signatures most sensitive to mesh refinement. Results are also presented for the two propagation test cases, which investigate the effects of atmospheric profiles on ground noise. Propagation is handled with an augmented Burgers' equation method (NASA's sBOOM), and ground noise metrics are computed with LCASB.

  11. Diffraction of sonic booms around buildings resulting in the building spiking effect.

    Science.gov (United States)

    Cho, Sang-Ik T; Sparrow, Victor W

    2011-03-01

    The diffraction of a sonic boom around a building of finite dimensions yields amplification of the front shock and a positive spike that follows the tail shock in the pressure waveform recorded at the incident side of the building's exterior surface. This physical phenomenon is consistently found both in the data obtained from a 2006 NASA flight test and field experiment, and in the finite-difference time-domain simulation that models this particular experiment, and the authors call it the "building spiking" effect. This paper presents an analysis of the numerical and the accompanying experimental results used to investigate the cause of this effect. The simulation assumes linear acoustics only, which sufficiently describes the physics of interest. Separating the low and high frequency components of boom recordings using optimal finite impulse response filters with complementary magnitude responses shows that the building spiking effect can be attributed to the frequency dependent nature of diffraction. A comparison of the building spiking effect of a conventional N-wave and a low-amplitude sonic boom shows that a longer shock rise time leads to less pronounced amplification of the exterior pressure loading on buildings, and thus reveals an advantage of shaping a boom to elongate its rise time. © 2011 Acoustical Society of America

  12. Equity in an Educational Boom: Lessons from the Expansion and Marketisation of Tertiary Schooling in Poland

    Science.gov (United States)

    Herbst, Mikolaj; Rok, Jakub

    2014-01-01

    This article shows how the probability of enrolment in tertiary schools has evolved for different social groups in Poland during the period of the educational boom. It also analyses how the socio-economic status influences the choices between full-time and part-time studies (the latter being of relatively low quality), and the probability of…

  13. Construction and Control of an active suspension for a field sprayer boom

    DEFF Research Database (Denmark)

    Nielsen, Henrik Skovsgaard; Sørensen, Paul Haase

    1998-01-01

    perforamnce of an active and passive boom suspension. A model has been made of an advanced active system, that combines a traditional trapezoid, with a spring pendulum system. The system can be described with a linear forth order model. The system has been the foundation for an active suspension...

  14. Investigating the pore-water chemistry effects on the volume change behaviour of Boom clay

    Science.gov (United States)

    Deng, Y. F.; Cui, Y. J.; Tang, A. M.; Nguyen, X. P.; Li, X. L.; Van Geet, M.

    The Essen site has been chosen as an alternative site for nuclear waste disposal in Belgium. The soil formation involved at this site is the same as at Mol site: Boom clay. However, owing to its geographical situation closer to the sea, Boom clay at Essen presents a pore water salinity 4-5 times higher than Boom clay at Mol. This study aims at studying the effects of pore water salinity on the hydro-mechanical behaviour of Boom clay. Specific oedometer cells were used allowing “flushing” the pore water in soil specimen by synthetic pore water or distilled water. The synthetic pore water used was prepared with the chemistry as that for the site water: 5.037 g/L for core Ess83 and 5.578 g/L for core Ess96. Mechanical loading was then carried out on the soil specimen after flushing. The results show that water salinity effect on the liquid limit is negligible. The saturation or pore water replacement under the in situ effective stress of 2.4 MPa does not induce significant volume change. For Ess83, hydro-mechanical behaviour was found to be slightly influenced by the water salinity; on the contrary, no obvious effect was identified on the hydro-mechanical behaviour of Ess96. This can be attributed to the higher smectite content in Ess83 than in Ess96.

  15. Formulation of the problem of sonic boom by a maneuvering aerofoil ...

    Indian Academy of Sciences (India)

    For the structure of a sonic boom produced by a simple aerofoil at a large distance from its source we ... The leading shock front (let us call it LS) starting from the nose of the aircraft gives rise to a sudden pressure increase ...... Alexander Von Humboldt Foundation for providing financial support to work in Germany and Prof.

  16. Higher Education and the Minerals Boom: A View from the Regions

    Science.gov (United States)

    Bell, Philip

    2014-01-01

    This paper examines the impact of the minerals boom to date on the demand for higher education in Central Queensland, and the sustainability of higher education providers in high economic growth environments. Several datasets were used to examine changes in the demand for higher education among specific student groups within the region, the…

  17. Summary of the 2008 NASA Fundamental Aeronautics Program Sonic Boom Prediction Workshop

    Science.gov (United States)

    Park, Michael A.; Aftosmis, Michael J.; Campbell, Richard L.; Carter, Melissa B.; Cliff, Susan; Nangert, Linda S.

    2013-01-01

    The Supersonics Project of the NASA Fundamental Aeronautics Program organized an internal sonic boom workshop to evaluate near- and mid-field sonic boom prediction capability at the Fundamental Aeronautics Annual Meeting in Atlanta, Georgia on October 8, 2008. Workshop participants computed sonic boom signatures for three non-lifting bodies and two lifting configurations. A cone-cylinder, parabolic, and quartic bodies of revolution comprised the non-lifting cases. The lifting configurations were a simple 69-degree delta wing body and a complete low-boom transport configuration designed during the High Speed Research Project in the 1990s with wing, body, tail, nacelle, and boundary layer diverter components. The AIRPLANE, Cart3D, FUN3D, and USM3D ow solvers were employed with the ANET signature propagation tool, output-based adaptation, and a priori adaptation based on freestream Mach number and angle of attack. Results were presented orally at the workshop. This article documents the workshop, results, and provides context on previously available and recently developed methods.

  18. The Baby Boom Generation and the Labor Market in the Next Decade.

    Science.gov (United States)

    Russell, Louise B.

    1983-01-01

    Despite alarming predictions, the worklife expectations of America's "baby boom" generation may not be much different from those of other age cohorts. Besides demography, factors like technological change, industrial structures, and methods of management have a great influence on job availability. Employment trends remain difficult to…

  19. Changing Fortunes: How China’s Boom Caused the Financial Crisis

    NARCIS (Netherlands)

    H. Mees (Heleen)

    2012-01-01

    textabstractThis dissertation includes five academic papers that – one way or the other – all relate to China. The first paper delivers proof for the central thesis of this thesis, which is that China’s boom caused the 2008 financial crisis and ensuing recession. As much as I hoped from the outset

  20. The Major Impacts of the Baby Boom Cohort upon American Life, Past, Present and Future.

    Science.gov (United States)

    Whaley, Charles E.

    Impacts of the "Baby Boom" generation, the 75 million persons born between 1947 and 1962 in the United States, are analyzed. Factors influencing this unprecedented increase in birth rates included "catching up" by men who had been at war, a higher proportion of women in childbearing years, a decrease in the average marriage…

  1. 76 FR 20530 - Safety Zone; Boom Days, Buffalo Outer Harbor, Buffalo, NY

    Science.gov (United States)

    2011-04-13

    ...[deg]51'47.61'' W (NAD 83). (b) Effective period. This regulation will be effective and the safety zone...-AA00 Safety Zone; Boom Days, Buffalo Outer Harbor, Buffalo, NY AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone in the Buffalo Outer...

  2. Politics and Nigerian agriculture in the first decade of the "Oil boom ...

    African Journals Online (AJOL)

    Politics and Nigerian agriculture in the first decade of the "Oil boom", 1970-1980: a preliminary assessment. A Olorunfemi, OC Adesina. Abstract. No Abstract. The Nigerian Journal of Economic History VoL. 1, 1998: 57-69. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  3. BABY BOOM (BBM) ChIP-seq in Arabidopsis somatic embryo tissue

    NARCIS (Netherlands)

    Horstman, A.; Muino Acuna, J.M.; Boutilier, K.A.

    2014-01-01

    After fertilization, a plant's life relies on progression through embryogenesis and maintenance of the stem cell niches from which all post-embryonic organs arise. BABY BOOM (BBM) and other members of the AINTEGUMENTA-LIKE (AIL)/PLETHORA (PLT) clade of the AP2-type transcription factor family play

  4. Investigating the pore-water chemistry effects on the volume change behaviour of Boom clay

    International Nuclear Information System (INIS)

    Deng, Y. F.; Cui, Y. J.; Tang, A. M.; Nguyen, X. P.; Li, X. L.; Van Geet, M.

    2011-01-01

    The Essen site has been chosen as an alternative site for nuclear waste disposal in Belgium. The soil formation involved at this site is the same as at Mol site: Boom clay. However, owing to its geographical situation closer to the sea, Boom clay at Essen presents a pore water salinity 4-5 times higher than Boom clay at Mol. This study aims at studying the effects of pore water salinity on the hydro-mechanical behaviour of Boom clay. Specific odometer cells were used allowing 'flushing' the pore water in soil specimen by synthetic pore water or distilled water. The synthetic pore water used was prepared with the chemistry as that for the site water: 5.037 g/L for core Ess83 and 5.578 g/L for core Ess96. Mechanical loading was then carried out on the soil specimen after flushing. The results show that water salinity effect on the liquid limit is negligible. The saturation or pore water replacement under the in situ effective stress of 2.4 MPa does not induce significant volume change. For Ess83, hydro-mechanical behaviour was found to be slightly influenced by the water salinity; on the contrary, no obvious effect was identified on the hydro-mechanical behaviour of Ess96. This can be attributed to the higher smectite content in Ess83 than in Ess96. (authors)

  5. 78 FR 29289 - Safety Zone; Big Bay Boom, San Diego Bay, San Diego, CA

    Science.gov (United States)

    2013-05-20

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Big Bay Boom, San Diego Bay, San Diego, CA... establish four temporary safety zones upon the navigable waters of San Diego ] Bay for the Port of San Diego... docket number using any one of the following methods: (1) Federal eRulemaking Portal: http://www...

  6. Economic news through the magnifying glass : How the media cover economic boom and bust

    NARCIS (Netherlands)

    van Dalen, A.; de Vreese, C.; Albæk, E.

    2017-01-01

    One of the normative functions of economic news is surveillance, making monitorial citizens aware of significant economic developments. In this light, it is important to look at the way economic news covers periods of recession and economic boom. Previous studies have focused on how the media cover

  7. Effects of temperature and thermally-induced microstructure change on hydraulic conductivity of Boom Clay

    Directory of Open Access Journals (Sweden)

    W.Z. Chen

    2017-06-01

    Full Text Available Boom Clay is one of the potential host rocks for deep geological disposal of high-level radioactive nuclear waste in Belgium. In order to investigate the mechanism of hydraulic conductivity variation under complex thermo-mechanical coupling conditions and to better understand the thermo-hydro-mechanical (THM coupling behaviour of Boom Clay, a series of permeability tests using temperature-controlled triaxial cell has been carried out on the Boom Clay samples taken from Belgian underground research laboratory (URL HADES. Due to its sedimentary nature, Boom Clay presents across-anisotropy with respect to its sub-horizontal bedding plane. Direct measurements of the vertical (Kv and horizontal (Kh hydraulic conductivities show that the hydraulic conductivity at 80 °C is about 2.4 times larger than that at room temperature (23 °C, and the hydraulic conductivity variation with temperature is basically reversible during heating–cooling cycle. The anisotropic property of Boom Clay is studied by scanning electron microscope (SEM tests, which highlight the transversely isotropic characteristics of intact Boom Clay. It is shown that the sub-horizontal bedding feature accounts for the horizontal permeability higher than the vertical one. The measured increment in hydraulic conductivity with temperature is lower than the calculated one when merely considering the changes in water kinematic viscosity and density with temperature. The nuclear magnetic resonance (NMR tests have also been carried out to investigate the impact of microstructure variation on the THM properties of clay. The results show that heating under unconstrained boundary condition will produce larger size of pores and weaken the microstructure. The discrepancy between the hydraulic conductivity experimentally measured and predicted (considering water viscosity and density changes with temperature can be attributed to the microstructural weakening effect on the thermal volume change

  8. Raptor responses to low-level jet aircraft and sonic booms

    Science.gov (United States)

    Ellis, David H.; Ellis, Catherine H.; Mindell, David P.

    1991-01-01

    We estimated effects of low-level military jet aircraft and mid- to high-altitude sonic booms (actual and simulated) on nesting peregrine falcons (Falco peregrinus) and seven other raptors by observing their responses to test stimuli, determining nesting success for the test year, and evaluating site reoccupancy rates for the year following the tests. Frequent and nearby jet aircraft passes: (1) sometimes noticeably alarmed birds, (2) occasionally caused birds to fly from perches or eyries, (3) most often evoked only minimal responses, and (4) were never associated with reproductive failure. Similarly, responses to real and simulated mid- to high-altitude sonic booms were often minimal and never appeared productivity limiting. Eighteen (95%) of 19 nest sites subjected to low-level jet flights and/or simulated sonic booms in 1980 fledged young during that year. Eighteen (95%) of 19 sites disturbed in 1980 were reoccupied by pairs or lone birds of the same species in 1981.We subjected four pairs of prairie falcons (Falco mexicanus) to low-level aircraft at ad libitum levels during the courtship and incubation phases when adults were most likely to abandon: all four eyries fledged young. From heart rate (HR) data taken via a telemetering egg at another prairie falcon eyrie, we determined that stimulus-induced HR alterations were comparable to rate changes for birds settling to incubate following flight.While encouraging, our findings cannot be taken as conclusive evidence that jet flights and/or sonic booms will have no long-term negative effects for other raptor species or for other areas. In addition, we did not experiment with totally naive wild adults, rotary-winged aircraft, or low-level sonic booms.

  9. A wing design methodology for low-boom low-drag supersonic business jet

    Science.gov (United States)

    Le, Daniel B.

    2009-12-01

    The arguably most critical hindrance to the successful development of a commercial supersonic aircraft is the impact of the sonic boom signature. The sonic boom signature of a supersonic aircraft is predicted using sonic boom theory, which formulates a relationship between the complex three-dimensional geometry of the aircraft to the pressure distribution and decomposes the geometry in terms of simple geometrical components. The supersonic aircraft design process is typically based on boom minimization theory. This theory provides a theoretical equivalent area distribution which should be matched by the conceptual design in order to achieve the pre-determined sonic boom signature. The difference between the target equivalent area distribution and the actual equivalent area distribution is referred to here as the gap distribution. The primary intent of this dissertation is to provide the designer with a systematic and structured approach to designing the aircraft wings with limited changes to the baseline concept while achieving critical design goals. The design process can be easily overwhelmed and may be difficult to evaluate their effectiveness. The wing design is decoupled into two separate processes, one focused on the planform design and the other on the camber design. Moreover, this design methodology supplements the designer by allowing trade studies to be conducted between important design parameters and objectives. The wing planform design methodology incorporates a continuous gradient-based optimization scheme to supplement the design process. This is not meant to substitute the vast amount of knowledge and design decisions that are needed for a successful design. Instead, the numerical optimization helps the designer to refine creative concepts. Last, this dissertation integrates a risk mitigation scheme throughout the wing design process. The design methodology implements minimal design changes to the wing geometry white achieving the target design goal

  10. Physical model of a floating trash boom to control aquatic weeds at the TVA Widows Creek Fossil Plant

    International Nuclear Information System (INIS)

    Hopping, P.N.

    1991-01-01

    This paper reports that the Tennessee Valley Authority (TVA) Widows Creek Fossil plant seasonally encounters adverse accumulations of aquatic weeds at the intakes of the condenser cooling water pumps. To reduce the accumulations, a floating trash boom has been proposed for the intakes. To evaluate the hydraulic feasibility of a boom, a physical model of the intakes has been built at the TVA Engineering Laboratory. The model was used to determine the boom alignment and depth of skimming needed to successfully deflect weeds away from the intakes and provide self-cleaning

  11. Electron microprobe analysis (WDS EPMA) of Zhamanshin glass reveals the impactor and a common role of accretion in the origin of splash-form impact glass

    International Nuclear Information System (INIS)

    Vetvicka, I; Frank, J; Drtina, J

    2010-01-01

    Impact glass samples collected during expeditions to the Zhamashin and Lonar craters were subjected to a morphology survey and compared to Wabar, Henbury and Darwin impact glasses to reveal that the accretion of fibres and spherules is not exclusive for irghizites but occurs in other splash form glasses over the world. WDS EPMA and LA-ICP-MS assays of Zhamanshin and Lonar glasses enabled the definition of akmurynites as Zhamanshin glass of specific morphology, chemistry and absence of extraterrestrial contamination. However, extraterrestrial contamination in irghizites was verified and further WDS EPMA analyses led to the conclusion that the Zhamanshin crater had been formed by the impact of a primitive achondrite of Lodran chemistry.

  12. New York Marcellus Shale: Industry boom put on hold

    Energy Technology Data Exchange (ETDEWEB)

    Mercurio, Angelique

    2012-01-16

    , New Mexico, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Texas, Utah, West Virginia, and Wyoming are pursuing. Positive labor market impacts are another major economic draw. According to the Revised Draft SGEIS on the Oil, Gas and Solution Mining Regulatory Program (September 2011), hydraulic fracturing would create between 4,408 and 17,634 full-time equivalent (FTE) direct construction jobs in New York State. Indirect employment in other sectors would add an additional 29,174 FTE jobs. Furthermore, the SGEIS analysis suggests that drilling activities could add an estimated $621.9 million to $2.5 billion in employee earnings (direct and indirect) per year, depending upon how much of the shale is developed. The state would also receive direct tax receipts from leasing land, and has the potential to see an increase in generated indirect revenue. Estimates range from $31 million to $125 million per year in personal income tax receipts, and local governments would benefit from revenue sharing. Some landowner groups say the continued delay in drilling is costing tens of thousands of jobs and millions of dollars in growth for New York, especially in the economically stunted upstate. A number of New York counties near Pennsylvania, such as Chemung, NY, have experienced economic uptick from Pennsylvania drilling activity just across the border. Chemung officials reported that approximately 1,300 county residents are currently employed by the drilling industry in Pennsylvania. The Marcellus shale boom is expected to continue over the next decade and beyond. By 2015, gas drilling activity could bring 20,000 jobs to New York State alone. Other states, such as Pennsylvania and West Virginia, are also expected to see a significant increase in the number of jobs. Catalyst 2: Political Reality of the Moratorium. Oil and gas drilling has taken place in New York since the 19th century, and it remains an important industry with more than 13,000 currently active wells. The

  13. Mapping the Expansion of Boom Crops in Mainland Southeast Asia Using Dense Time Stacks of Landsat Data

    Directory of Open Access Journals (Sweden)

    Kaspar Hurni

    2017-03-01

    Full Text Available We performed a multi-date composite change detection technique using a dense-time stack of Landsat data to map land-use and land-cover change (LCLUC in Mainland Southeast Asia (MSEA with a focus on the expansion of boom crops, primarily tree crops. The supervised classification was performed using Support Vector Machines (SVM, which are supervised non-parametric statistical learning techniques. To select the most suitable SMV classifier and the related parameter settings, we used the training data and performed a two-dimensional grid search with a three-fold internal cross-validation. We worked in seven Landsat footprints and found the linear kernel to be the most suitable for all footprints, but the most suitable regularization parameter C varied across the footprints. We distinguished a total of 41 LCLUCs (13 to 31 classes per footprint in very dynamic and heterogeneous landscapes. The approach proved useful for distinguishing subtle changes over time and to map a variety of land covers, tree crops, and transformations as long as sufficient training points could be collected for each class. While to date, this approach has only been applied to mapping urban extent and expansion, this study shows that it is also useful for mapping change in rural settings, especially when images from phenologically relevant acquisition dates are included.

  14. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  15. Opportunities offered by the raw material boom to German mining machinery manufacturers; Chancen des Rohstoffbooms fuer die deutschen Bergbaumaschinenhersteller

    Energy Technology Data Exchange (ETDEWEB)

    Stoeckmann, K. [Verband Deutscher Maschinen- und Anlagenbau e.V. (VDMA), Frankfurt am Main (Germany). Fachverband Bergbaumaschinen

    2008-05-13

    Since the beginning of the raw material boom four years ago the positive trend in the mining machinery branch in Germany has accelerated. The globalisation of the branch was assisted by the good national and international network between manufacturers of mining equipment, associations, consultants, financial institutions and politicians. The branch is currently well established internationally with an export share of 86%. This puts it into a position to continue to utilise the opportunities offered by the raw material boom. (orig.)

  16. Validation of sonic boom propagation codes using SR-71 flight test data.

    Science.gov (United States)

    Ivanteyeva, Lyudmila G; Kovalenko, Victor V; Pavlyukov, Evgeny V; Teperin, Leonid L; Rackl, Robert G

    2002-01-01

    The results of two sonic boom propagation codes, ZEPHYRUS (NASA) and BOOM (TsAGI), are compared with SR-71 flight test data from 1995. Options available in the computational codes are described briefly. Special processing methods are described which were applied to the experimental data. A method to transform experimental data at close ranges to the supersonic aircraft into initial data required by the codes was developed; it is applicable at any flight regime. Data are compared in near-, mid-, and far fields. The far-field observation aircraft recorded both direct and reflected waves. Comparison of computed and measured results shows good agreement with peak pressure, duration, and wave shape for direct waves, thus validating the computational codes.

  17. Prime Borrowers and Financial Innovation in the Housing Boom and Bust

    DEFF Research Database (Denmark)

    Bäckman, Claes; Lutz, Chandler

    We use the introduction of interest-only (IO) mortgages in Denmark as a natural experiment to assess the impact of alternative mortgage products on house prices during the 2000s. We construct a model to show that lower amortization payments lead to an increase in credit demand by allowing...... for better consumption smoothing, even absent any shift in credit supply. In support of the model, we find that the introduction of interest-only mortgages was followed by a large increase in the number of buyers, even as credit quality remained constant. On the aggregate level the results indicate...... that interest-only mortgages amplified the boom-bust pattern in housing: house prices increased an additional 35 percent during the boom due to IO loans, and subsequently reverse during the bust. These effects, which cannot be explained by changes in lending standards or shifts in credit supply, are magnified...

  18. Effects of Aircraft Noise and Sonic Booms on Domestic Animals and Wildlife: A Literature Synthesis

    Science.gov (United States)

    1988-06-01

    stressful conditions with changes in the hemogram. An inverted neutrophil- lymphocyte ratio appeared to be diagnostic of stress. Of the stressors used...concentrations (Stephens 1980). Techniques for determin- ing plasma corticosteroids in the dog make it possible to evaluate adrenal function. The canine adrenal... eruption , explosion, or earthquake at sea generating a tidal wave. When the sonic booms were audible, the songbirds uttered "raucous discordant cries

  19. The design and testing of a memory metal actuated boom release mechanism

    Science.gov (United States)

    Powley, D. G.; Brook, G. B.

    1979-01-01

    A boom latch and release mechanism was designed, manufactured and tested, based on a specification for the ISEE-B satellite mechanism. From experimental results obtained, it is possible to calculate the energy available and the operating torques which can be achieved from a torsional shape memory element in terms of the reversible strain induced by prior working. Some guidelines to be followed when designing mechanisms actuated by shape memory elements are included.

  20. Mediating the microcomputer: The educational character of the 1980s British popular computing boom.

    Science.gov (United States)

    Lean, Thomas

    2013-07-01

    In the early 1980s the computer entered the British home in significant numbers for the first time as many thousands of people purchased their first personal 'microcomputer'. In this paper I explore the educational character of the home computer boom, a response to unease over the impact of new information technologies. Media, government, social movements and computer manufacturers constituted a systematic effort to enhance the public understanding of a new technology that was anticipated to change the world.

  1. Treatment of psychiatric problems a growth industry in midst of Chile's booming economy.

    Science.gov (United States)

    Sagaris, L

    1996-07-01

    Five years after an elected government took over from a military regime, Chile has enjoyed booming economic growth and some measure of political stability but the scars of the legacy left by the regime of Augusto Pinochet run deep. Alcohol and drug abuse, family violence, depression and other mental-health problems are reported by a large proportion of the population. Fear is one of the permanent consequences of the military regime, says one sociologist.

  2. Between the colonial heritage and the first globalization boom: on income inequality in the Southern Cone

    OpenAIRE

    Bertola Flores, Luis Eduardo; Castelnovo, Cecilia; Rodriguez Arroyo, Javier; Willebald Remedios, Henry Francisco

    2010-01-01

    Special Issue on Latin American Inequality. This paper presents a first estimate of income inequality in the Southern Cone of South America (Brazil 1872 and 1920, Chile 1870 and 1920, Uruguay 1920) and some assumptions with regard to Argentina (1870 and 1920) and Uruguay (1870). We find that income distribution was relatively high on the eve of the first globalization boom. Thus, inequality is not only the result of globalization, but also a structural feature. Inequality increased between...

  3. Dynamic Analysis of the Flexible Boom in the N-ROSS Satellite.

    Science.gov (United States)

    1987-03-01

    ZSLOP(LCN= ’DEQ’ RU = ILI=I) ZSL.OP( PO=0.,A-X,= OMIT-.R = 2.Lf= 2),. ZSLOP( P0= ..AX= OMI~T,RU =3.LI = 3) LABEL ( Gil) APPLIED TORQUE L- ABEL (012...School Monterey, CA 93943) 146 14. Kane Choone soon 7 P.O.-ox 17 Kang Nam Gu. Ban Po 2 Dong Kane Nam Won. 11yo Sung Villa 5;201 Scot. Republic of Korea 15

  4. Atmospheric turbulence conditions leading to focused and folded sonic boom wave fronts.

    Science.gov (United States)

    Piacsek, Andrew A

    2002-01-01

    The propagation and subsequent distortion of sonic booms with rippled wave fronts are investigated theoretically using a nonlinear time-domain finite-difference scheme. This work seeks to validate the rippled wave front approach as a method for explaining the significant effects of turbulence on sonic booms [A. S. Pierce and D. J. Maglieri, J. Acoust. Soc. Am. 51, 702-721 (1971)]. A very simple description of turbulence is employed in which velocity perturbations within a shallow layer of the atmosphere form strings of vortices characterized by their size and speed. Passage of a steady-state plane shock front through such a vortex layer produces a periodically rippled wave front which, for the purposes of the present investigation, serves as the initial condition for a finite-difference propagation scheme. Results show that shock strength and ripple curvature determine whether ensuing propagation leads to wave front folding. High resolution images of the computed full wave field provide insights into the spiked and rounded features seen in sonic booms that have propagated through turbulence.

  5. Computational Support of 9x7 Wind Tunnel Test of Sonic Boom Models with Plumes

    Science.gov (United States)

    Jensen, James C.; Denison, Marie; Durston, Don; Cliff, Susan E.

    2017-01-01

    NASA and its industry partners are performing studies of supersonic aircraft concepts with low sonic boom pressure signatures. The interaction of the nozzle jet flow with the aircrafts' aft components is typically where the greatest uncertainly in the pressure signature is observed with high-fidelity numerical simulations. An extensive wind tunnel test was conducted in February 2016 in the NASA Ames 9- by 7- Foot Supersonic Wind Tunnel to help address the nozzle jet effects on sonic boom. Five test models with a variety of shock generators of differing waveforms and strengths were tested with a convergent-divergent nozzle for a wide range of nozzle pressure ratios. The LAVA unstructured flow solver was used to generate first CFD comparisons with the new experimental database using best practice meshing and analysis techniques for sonic boom vehicle design for all five different configurations. LAVA was also used to redesign the internal flow path of the nozzle and to better understand the flow field in the test section, both of which significantly improved the quality of the test data.

  6. Wind Tunnel Model Design for Sonic Boom Studies of Nozzle Jet with Shock Interactions

    Science.gov (United States)

    Cliff, Susan E.; Denison, Marie; Sozer, Emre; Moini-Yekta, Shayan

    2016-01-01

    NASA and Industry are performing vehicle studies of configurations with low sonic boom pressure signatures. The computational analyses of modern configuration designs have matured to the point where there is confidence in the prediction of the pressure signature from the front of the vehicle, but uncertainty in the aft signatures with often greater boundary layer effects and nozzle jet pressures. Wind tunnel testing at significantly lower Reynolds numbers than in flight and without inlet and nozzle jet pressures make it difficult to accurately assess the computational solutions of flight vehicles. A wind tunnel test in the NASA Ames 9- by 7-Foot Supersonic Wind Tunnel from Mach 1.6 to 2.0 will be used to assess the effects of shocks from components passing through nozzle jet plumes on the sonic boom pressure signature and provide datasets for comparison with CFD codes. A large number of high-fidelity numerical simulations of wind tunnel test models with a variety of shock generators that simulate horizontal tails and aft decks have been studied to provide suitable models for sonic boom pressure measurements using a minimally intrusive pressure rail in the wind tunnel. The computational results are presented and the evolution of candidate wind tunnel models is summarized and discussed in this paper.

  7. Overview of feasibility study on conducting overflight measurements of shaped sonic boom signatures using RPV's

    Science.gov (United States)

    Maglieri, Domenic J.; Sothcott, Victor E.; Keefer, Thomas N., Jr.; Bobbitt, Percy J.

    1992-04-01

    Before beginning this presentation, it is appropriate to acknowledge the sincere interest and financial support provided by the NASA LaRC under contract NAS9-17900. An outline of the material to be used in the present paper is given. It begins with a indication of the origin and objectives of the feasibility study. This is followed by a discussion of various simulation methods of establishing the persistence of shaped sonic boom signatures to large distances including the use of recoverable RPV/drones. The desirable features to be sought out in an RPV along with a rationale for the selection of a 'shaped' sonic boom signature will be addressed. Three candidate vehicles are examined as to their suitability with respect to a number of factors, in particular, modifiability. Area distributions and associated sonic boom signatures of the basic and modified Firebee vehicle will also be shown. An indication of the scope of the proposed wind tunnel and flight test programs will be presented including measurement technologies and predicted waveforms. Finally, some remarks will be made summarizing the study and highlighting the key findings.

  8. Nondestructive Online Detection of Welding Defects in Track Crane Boom Using Acoustic Emission Technique

    Directory of Open Access Journals (Sweden)

    Yong Tao

    2014-04-01

    Full Text Available Nondestructive detection of structural component of track crane is a difficult and costly problem. In the present study, acoustic emission (AE was used to detect two kinds of typical welding defects, that is, welding porosity and incomplete penetration, in the truck crane boom. Firstly, a subsidiary test specimen with special preset welding defect was designed and added on the boom surface with the aid of steel plates to get the synchronous deformation of the main boom. Then, the AE feature information of the welding defect could be got without influencing normal operation of equipment. As a result, the rudimentary location analysis can be attained using the linear location method and the two kinds of welding defects can be distinguished clearly using AE characteristic parameters such as amplitude and centroid frequency. Also, through the comparison of two loading processes, we concluded that the signal produced during the first loading process was mainly caused by plastic deformation damage and during the second loading process the stress release and structure friction between sections in welding area are the main acoustic emission sources. Thus, the AE is an available tool for nondestructive online detection of latent welding defects of structural component of track crane.

  9. Design of an Indoor Sonic Boom Simulator at NASA Langley Research Center

    Science.gov (United States)

    Klos, Jacob; Sullivan, Brenda M.; Shepherd, Kevin P.

    2008-01-01

    Construction of a simulator to recreate the soundscape inside residential buildings exposed to sonic booms is scheduled to start during the summer of 2008 at NASA Langley Research Center. The new facility should be complete by the end of the year. The design of the simulator allows independent control of several factors that create the indoor soundscape. Variables that will be isolated include such factors as boom duration, overpressure, rise time, spectral shape, level of rattle, level of squeak, source of rattle and squeak, level of vibration and source of vibration. Test subjects inside the simulator will be asked to judge the simulated soundscape, which will represent realistic indoor boom exposure. Ultimately, this simulator will be used to develop a functional relationship between human response and the sound characteristics creating the indoor soundscape. A conceptual design has been developed by NASA personnel, and is currently being vetted through small-scale risk reduction tests that are being performed in-house. The purpose of this document is to introduce the conceptual design, identify how the indoor response will be simulated, briefly outline some of the risk reduction tests that have been completed to vet the design, and discuss the impact of these tests on the simulator design.

  10. Boomtown blues: a community history of oil shale booms in the Colorado River Valley

    Energy Technology Data Exchange (ETDEWEB)

    Gulliford, A.J.

    1986-01-01

    The routes of early surveyors and explorers and the mining and agricultural history of the valley are examined in detail as are the ethnic origins of family networks that emerged over generations and were affected by the first oil shale boom between 1915-1925 when major oil companies acquired ranchland, water rights, and oil-shale claims in Garfield County, Colorado. The first boom faded and community equilibrium and solidarity were regained during the depression. By the mid-1970s, major national and international forces again focused on Garfield County and its three trillion barrels of oil locked in shale. President Carter's push for energy self-sufficiency as the moral equivalent of war, and loans made by the synthetic Fuels Corporation for oil shale development, came into direct conflict with national environmental groups and federal environmental laws. Local ranching communities became urbanized boomtowns, especially after Exxon, USA embarked on the $5 billion dollar Colony Oil Shale Project. Less than two years later, on May 2, 1982, Exxon announced the immediate closure of Colony and threw 2100 people out of work and eliminated $85 million in annual payroll from western Colorado. Social and psychological community effects of the oil shale boom and bust are vividly chronicled here.

  11. Numerical and experimental investigation of VG flow control for a low-boom inlet

    Science.gov (United States)

    Rybalko, Michael

    The application of vortex generators (VGs) for shock/boundary layer interaction flow control in a novel external compression, axisymmetric, low-boom concept inlet was studied using numerical and experimental methods. The low-boom inlet design features a zero-angle cowl and relaxed isentropic compression centerbody spike, resulting in defocused oblique shocks and a weak terminating normal shock. This allows reduced external gas dynamic waves at high mass flow rates but suffers from flow separation near the throat and a large hub-side boundary layer at the Aerodynamic Interface Plane (AIP), which marks the inflow to the jet engine turbo-machinery. Supersonic VGs were investigated to reduce the shock-induced flow separation near the throat while subsonic VGs were investigated to reduce boundary layer radial distortion at the AIP. To guide large-scale inlet experiments, Reynolds-Averaged Navier-Stokes (RANS) simulations using three-dimensional, structured, chimera (overset) grids and the WIND-US code were conducted. Flow control cases included conventional and novel types of vortex generators at positions both upstream of the terminating normal shock (supersonic VGs) and downstream (subsonic VGs). The performance parameters included incompressible axisymmetric shape factor, post-shock separation area, inlet pressure recovery, and mass flow ratio. The design of experiments (DOE) methodology was used to select device size and location, analyze the resulting data, and determine the optimal choice of device geometry. Based on the above studies, a test matrix of supersonic and subsonic VGs was adapted for a large-scale inlet test to be conducted at the 8'x6' supersonic wind tunnel at NASA Glenn Research Center (GRC). Comparisons of RANS simulations with data from the Fall 2010 8'x6' inlet test showed that predicted VG performance trends and case rankings for both supersonic and subsonic devices were consistent with experimental results. For example, experimental surface oil

  12. The Control of Welding Deformation of the Three-Section Arm of Placing Boom of HB48B Pump Truck

    Science.gov (United States)

    Wang, Zhi-ling

    2018-02-01

    The concrete pump truck is the construction equipment of conveying concrete with self contained base plate and distributing boom. It integrates the pump transport mechanism of the concrete pump, and the hydraulic roll-folding type distributing boom used to distribute materials, and the supporting mechanism into the automobile chassis, and it is the concrete conveying equipment with high efficient and the functions of driving, pumping, and distributing materials. The placing boom of the concrete pump truck is the main force member in the pump parts with bearing great pressure, and its stress condition is complex. Taking the HB48B placing boom as an example, this paper analyzes and studies the deformation produced by placing boom of pump truck, and then obtains some main factors affecting the welding deformation. Through the riveter “joint” size, we controlled the process parameters, post-welding processing, and other aspects. These measures had some practical significance to prevent, control, and reduce the deformation of welding.

  13. Prisons as Panacea or Pariah? The Countervailing Consequences of the Prison Boom on the Political Economy of Rural Towns

    Directory of Open Access Journals (Sweden)

    John M. Eason

    2017-01-01

    Full Text Available The nascent literature on prison proliferation in the United States typically reveals negative impacts for communities of color. Given that Southern rural communities were the most likely to build during the prison boom (1970–2010, however, a more nuanced understanding of prison impact is warranted. Using a dataset matching and geocoding all 1663 U.S. prisons with their Census-appointed place, this study explores the countervailing consequences of the prison boom on rural towns across multiple periods. For example, locales that adopted prisons at earlier stages of the prison boom era received a short-term boom compared to those that did not, but these effects were not lasting. Furthermore, later in the boom, prison-building protected towns against additional economic decline. Thus, neither entirely pariah nor panacea, the prison functions as a state-sponsored public works program for disadvantaged rural communities but also supports perverse economic incentives for prison proliferation. Methodological, substantive, theoretical, and policy implications regarding the intersection of race and punishment are explored.

  14. Micro-fabric damages in Boom Clay inferred from cryo-BIB-SEM experiment: recent results

    Science.gov (United States)

    Desbois, Guillaume; Schmatz, Joyce; Klaver, Jop; Urai, Janos L.

    2017-04-01

    The Boom Clay is considered as a potential host rock in Belgium for nuclear waste disposal in a deep geological formation. One of the keys to understand the long-term performance of such a host rock is the fundamental understanding of coupling between microstructural evolution, poromechanical behaviour and the state of hydration of the system. At in situ conditions, Boom Clay is a nearly water-saturated (>94%) clay-rich geomaterial. Subsequently, for measurement of mechanical and transport properties in laboratory, cores of Boom Clay are vacuum-packed in Al-coated-poly-ethylene barrier foil to be best preserved at original hydric state. Because clay microstructures are very sensitive to dehydration, the validity of investigations done on such preserved or/and dried samples is often questionable. Desbois et al. (2009, 2013, 2014) showed the possibility to image fluid-filled porosity in Boom Clay, by using the FIB-cryo-SEM (FIB: Focussed Ion Beam) and FIB-cryo-SEM (BIB: Broad Ion Beam) techniques. However, surprisingly in Desbois et al. (2014), BIB-cryo-SEM experiments on Boom Clay, shown that the majority of the pores were fluid-free, contrasting with result in Desbois et al. (2009). In Desbois et al. (2014), several reasons were discussed to explain such discrepancies. The likely ones are the sealing efficiency of the Al-barrier foil at long term and the volume expansion due to the release of in-situ stress after core extraction, contributing both to dehydration and microfabric damage. This contribution presents the newest results based on cryo-BIB-SEM. Small pieces (30 mm3) of Boom Clay were preserved in liquid nitrogen after the core extraction at the MOL/Dessel Underground Research Laboratory in Belgium. A maximum of ten minutes time span was achieved between opening the core, the sub-sample extraction and the quenching of sub-samples in liquid nitrogen. First results show that all pores visible at cryo-SEM resolution are water saturated. However, water

  15. Effects of aircraft noise and sonic booms on domestic animals and wildlife: bibliographic abstracts

    Science.gov (United States)

    Gladwin, Douglas N.; Manci, Karen M.; Villella, Rita

    1988-01-01

    The purpose of this document is to provide an information base on the effects of aircraft noise and sonic booms on various animal species. Such information is necessary to assess potential impacts to wildlife populations from proposed military and other flight operations. To develop this document the National Ecology Center conducted a literature search of information pertaining to animals and wildlife. Information concerning other types of noise was also gathered to supplement the lack of knowledge on the effects of aircraft noise. The bibliographic abstracts in this report provide a compilation of current knowledge. No attempt was made to evaluate the appropriateness or adequacy of the scientific approach of each study.

  16. Jig-Shape Optimization of a Low-Boom Supersonic Aircraft

    Science.gov (United States)

    Pak, Chan-gi

    2018-01-01

    A simple approach for optimizing the jig-shape is proposed in this study. This simple approach is based on an unconstrained optimization problem and applied to a low-boom supersonic aircraft. In this study, the jig-shape optimization is performed using the two-step approach. First, starting design variables are computed using the least squares surface fitting technique. Next, the jig-shape is further tuned using a numerical optimization procedure based on in-house object-oriented optimization tool.

  17. Colorado's energy boom: impact on crime and criminal justice

    Energy Technology Data Exchange (ETDEWEB)

    1981-02-01

    Information is reported on the impact of rapid energy development on western slope criminal justice agencies. The focus is on crime rates, law enforcement, the courts, and juvenile justice problems. The problems that are likely to develop and what might be done to minimize the negative consequences are analyzed. The social characteristics of boom towns and the changes resulting from rapid growth, the changes in crime rates, the impact experienced by law enforcement agencies and the courts, and information on planning and funding in impact areas are described. (MCW)

  18. Comportement thermomécanique de l'argile de Boom

    Science.gov (United States)

    Sultan, Nabil; Delage, Pierre; Cui, Yu Jun

    Special attention has been recently paid on temperature effects on the behaviour of deep saturated clays, in relation with nuclear deep waste storage. However, few experimental data are presently available, and existing constitutive models need to be completed. This note is aimed at completing, both experimentally and theoretically, the understanding of the effects of the overconsolidation ratio on the thermal volume changes of Boom clay (Belgium). The experimental data obtained here are in a good agreement with existing data. As a complement to existing data, they are used to develop a new elastoplastic model. The adoption of a second coupled plastic mechanism provides good simulations on a complex thermo-mechanical path.

  19. The electrochemistry of carbon steel in simulated concrete pore water in boom clay repository environments

    Directory of Open Access Journals (Sweden)

    Rosas-Camacho O.

    2011-04-01

    Full Text Available The prediction of corrosion damage of canisters to experimentally inaccessible times is vitally important in assessing various concepts for the disposal of High Level Nuclear Waste. Such prediction can only be made using deterministic models, whose predictions are constrained by the time-invariant natural laws. In this paper, we describe the measurement of experimental electrochemical data that will allow the prediction of damage to the carbon steel overpack of the super container in Belgium’s proposed Boom Clay repository by using the Point Defect Model (PDM. PDM parameter values are obtained by optimizing the model on experimental, wide-band electrochemical impedance spectroscopy data.

  20. Background Pressure Profiles for Sonic Boom Vehicle Testing in the NASA Glenn 8- by 6-Foot Supersonic Wind Tunnel

    Science.gov (United States)

    Castner, Raymond; Shaw, Stephen; Adamson, Eric; Simerly, Stephanie

    2013-01-01

    In an effort to identify test facilities that offer sonic boom measurement capabilities, an exploratory test program was initiated using wind tunnels at NASA research centers. The subject of this report is the sonic boom pressure rail data collected in the Glenn Research Center 8- by 6-Foot Supersonic Wind Tunnel. The purpose is to summarize the lessons learned based on the test activity, specifically relating to collecting sonic boom data which has a large amount of spatial pressure variation. The wind tunnel background pressure profiles are presented as well as data which demonstrated how both wind tunnel Mach number and model support-strut position affected the wind tunnel background pressure profile. Techniques were developed to mitigate these effects and are presented.

  1. Dinámicas espaciales generadas a partir de las agroexportaciones: el boom de los espárragos en Ica

    Directory of Open Access Journals (Sweden)

    Brenda Toledo Asenjo

    2011-12-01

    Full Text Available Spatial Dynamics Generated by Agroexports: The Asparragus Boom at IcaDifferent economic and subsistence activities respond to changes or dynamics that are formed in each context. At present, globalization appears as one of the main factors that influence on the economic activities. That is, it is undeniable that all economic activities transform their processes induced by that phenomenon as well as the distinct regions have required to get integrated to that process. In that sense, the states, procuring to get integrated to the global context have contributed to the configuration of the new commercial scenery. This implies that many societies with distinct living patterns have had to adequate to a new commercial dynamics, where exports are the principal connection to the global market. The main objective of this paper is to identify and analyze the spatial dynamics originated as result of agro exports such as the case of the asparagus’ «boom» at the Ica Valley. Moreover, there is a revision of some environmental dynamics or impacts that the process has given way in order to have a correct vision of the topic. To do this, there was a spatial review of the study area based on satellite images in identified dates, from which it was possible to see gross evidence of a spatial transformation and the appearance of new land use formsLas distintas actividades económicas y de subsistencia responden a los cambios o dinámicas que se forman en cada contexto. Actualmente, la globalización aparece como uno de los factores principales de influencia sobre las actividades económicas. Es decir, es innegable que todas las actividades económicas transforman sus procesos inducidas por ese fenómeno, en la medida que las distintas regiones han requerido integrarse al proceso. En ese sentido, los Estados, al procurar sumarse al contexto global han contribuido a la configuración del nuevo escenario comercial. Esto implica que muchas sociedades con costumbres

  2. Gender Role Stereotypes in the "Dick and Jane" Basal Reader Series and Sustained Impression upon Women of the Baby Boom Generation

    Science.gov (United States)

    Hutchinson, Mary Louise

    2010-01-01

    This study explored the perceptions of women of the Baby Boom generation regarding the potential impact of gender role stereotypes contained in the children's reading series utilized in elementary school classrooms from 1946 through 1964. Particular emphasis was placed upon the prominent reading series of the Baby Boom Era, the Scott, Foresman and…

  3. Analysis of the Effects of Streamwise Lift Distribution on Sonic Boom Signature

    Science.gov (United States)

    Yoo, Paul

    2013-01-01

    Investigation of sonic boom has been one of the major areas of study in aeronautics due to the benefits a low-boom aircraft has in both civilian and military applications. This work conducts a numerical analysis of the effects of streamwise lift distribution on the shock coalescence characteristics. A simple wing-canard-stabilator body model is used in the numerical simulation. The streamwise lift distribution is varied by fixing the canard at a deflection angle while trimming the aircraft with the wing and the stabilator at the desired lift coefficient. The lift and the pitching moment coefficients are computed using the Missile DATCOM v. 707. The flow field around the wing-canard- stabilator body model is resolved using the OVERFLOW-2 flow solver. Overset/ chimera grid topology is used to simplify the grid generation of various configurations representing different streamwise lift distributions. The numerical simulations are performed without viscosity unless it is required for numerical stability. All configurations are simulated at Mach 1.4, angle-of-attack of 1.50, lift coefficient of 0.05, and pitching moment coefficient of approximately 0. Four streamwise lift distribution configurations were tested.

  4. Wind Tunnel Model Design for Sonic Boom Studies of Nozzle Jet Flows with Shock Interactions

    Science.gov (United States)

    Cliff, Susan E.; Denison, Marie; Moini-Yekta, Shayan; Morr, Donald E.; Durston, Donald A.

    2016-01-01

    NASA and the U.S. aerospace industry are performing studies of supersonic aircraft concepts with low sonic boom pressure signatures. The computational analyses of modern aircraft designs have matured to the point where there is confidence in the prediction of the pressure signature from the front of the vehicle, but uncertainty remains in the aft signatures due to boundary layer and nozzle exhaust jet effects. Wind tunnel testing without inlet and nozzle exhaust jet effects at lower Reynolds numbers than in-flight make it difficult to accurately assess the computational solutions of flight vehicles. A wind tunnel test in the NASA Ames 9- by 7-Foot Supersonic Wind Tunnel is planned for February 2016 to address the nozzle jet effects on sonic boom. The experiment will provide pressure signatures of test articles that replicate waveforms from aircraft wings, tails, and aft fuselage (deck) components after passing through cold nozzle jet plumes. The data will provide a variety of nozzle plume and shock interactions for comparison with computational results. A large number of high-fidelity numerical simulations of a variety of shock generators were evaluated to define a reduced collection of suitable test models. The computational results of the candidate wind tunnel test models as they evolved are summarized, and pre-test computations of the final designs are provided.

  5. Design study for a macropermeability test in an argillaceous formation (Boom clay)

    International Nuclear Information System (INIS)

    Bronders, J.

    1992-01-01

    In the present report a test design has been developed for determining the in-situ permeability of the Boom clay on a large scale at the Mol site (Belgium). Since in the Boom clay at the Mol site an Underground Repository Facility (URF) is operational the test has been designed to be run in or from this facility. The proposal is an in-situ macropermeability test with a set-up comprising a central borehole (metric scale in length) designed to allow various types of control of the water-level, surrounded by a lattice of piezometers installed in the clay mass for the monitoring of the interstitial water pressure changes in function of the various water-level controls. In one part the report describes the potential set-ups and a theoretical background as far as it can be done on the basis of existing literature and experiments. In a second part the method (technical and practical data of a test set-up) is described and documented. The method proposed is largely based on the several years of expertise gained within the field of in-situ migration and hydrogeologic investigations in the Hades-URF. 14 refs., 9 figs., 2 tabs

  6. Popular Demobilization, Agribusiness Mobilization, and the Agrarian Boom in Post-Neoliberal Argentina

    Directory of Open Access Journals (Sweden)

    Pablo Lapegna

    2015-08-01

    Full Text Available Based on ethnographic research, archival data, and a catalog of protest events, this article analyzes the relationship between popular social movements, business mobilization, and institutional politics in Argentina during the post-neoliberal phase, which arguably began circa 2003. How did waves of popular mobilization in the 1990s shape business mobilization in the 2000s? How did contentious politics influence institutional politics in the post-neoliberal period? What are the changes and continuities of the agrarian boom that cut across the neoliberal and post-neoliberal periods? While I zoom in on Argentina, the article goes beyond this case by contributing to three discussions. First, rather than limiting the analysis to the customary focus on the mobilization of subordinated actors, it examines the demobilization of popular social movements, the mobilization of business sectors, and the connections between the two. Second, it shows the ways in which the state can simultaneously challenge neoliberal principles while also favoring the global corporations that dominate the contemporary neoliberal food regime. Finally, the case of Argentina sheds light on the political economy of the "Left turn" in Latin America, particularly the negative socio-environmental impacts of commodity booms. The article concludes that researchers need to pay closer attention to the connections between contentious and institutional politics, and to the protean possibilities of neoliberalism to inspire collective actions.

  7. Geotechnical characterization of boom clay in relation to the disposal of radioactive waste

    International Nuclear Information System (INIS)

    Horseman, S.T.; Winter, M.G.; Enwistle, D.C.

    1987-01-01

    This report describes the results of a laboratory study on the geotechnical properties of the Tertiary Boom clay. Tests were performed on 'undisturbed' samples of clay taken from a location 247 m below surface at the SCK/CEN experimental site at Mol in Belgium. In geotechnical terms, the Boom clay (at depth) may be described as a hard, high-plasticity, overconsolidated clay. Test methods have included (a) the one-dimensional consolidation test with consolidation stresses up to 32 MPa, (b) the one dimensional swelling pressure test, (c) the isotropically-consolidated, undrained (CIU) triaxial test with pore pressure measurement, and (d) the unconsolidated undrained (UU) triaxial test. All triaxial tests were load-controlled. Limited test results are presented on pore pressure responses during heating under undrained conditions and on the effect of elevated temperature (80 O C) on deformability and strength. It is found that significantly large excess pore pressures (circa 1 MPa under in situ stress conditions) may be developed during heating from ambient laboratory temperature to 80 O C. The effect is due, at least in part, to the expansion of the pore fluid

  8. Macro policy responses to oil booms and busts in the United Arab Emirates

    International Nuclear Information System (INIS)

    Al-Mutawa, A.K.

    1991-01-01

    The effects of oil shocks and macro policy changes in the United Arab Emirates are analyzed. A theoretical model is developed within the framework of the Dutch Disease literature. It contains four unique features that are applicable to the United Arab Emirates' economy. There are: (1) the presence of a large foreign labor force; (2) OPEC's oil export quotas; (3) the division of oil profits; and (4) the important role of government expenditures. The model is then used to examine the welfare effects of the above-mentioned shocks. An econometric model is then specified that conforms to the analytical model. In the econometric model the method of 'principal components' is applied owing to the undersized sample data. The principal components methodology is used in both the identification testing and the estimation of the structural equations. The oil and macro policy shocks are then simulated. The simulation results show that an oil-quantity boom leads to a higher welfare gain than an oil-price boom. Under certain circumstances, this finding is also confirmed by the comparative statistics that follow from the analytical model

  9. Regional modelling of the confined aquifers below the Boom clay in NE-Belgium

    International Nuclear Information System (INIS)

    Vandersteen, K.; Gedeon, M.; Marivoet, J.; Wouters, L.

    2012-01-01

    Document available in extended abstract form only. In the framework of the Belgian research program on the long term management of high-level and/or long-lived radioactive waste coordinated by ONDRAF/NIRAS, the Boom Clay is considered as a reference host rock for the geological disposal of high-level radioactive waste in NE-Belgium (Campine area). The hydrogeological program at SCK.CEN supports the long-term performance assessments of the geological disposal of radioactive waste by performing a phenomenological research of the aquifer systems surrounding the studied disposal system. One of the important components of this programme is the regional hydrogeological modelling. The regional hydrogeology is studied using two main models - the steady state Neogene aquifer model (NAM) and the transient deep aquifer pumping model (DAP), developed to characterize and quantify the regional groundwater flow in, respectively, the aquifers lying above the Boom Clay in the Nete catchment area (NAM), and the aquifers lying below the Boom Clay in the Campine area (DAP). This paper describes the most recent update of the DAP model. The DAP model represents the confined part of the groundwater system located stratigraphically below the Boom Clay. This includes the parts of the Oligocene aquifer, the Bartoon aquitard system and the Ledo-Paniselian-Brusselian aquifer buried under the Boom Clay. Due to the considerable pumping from these aquifers in combination with a limited recharge, a gradual decrease in groundwater levels has been observed in more than 30-year piezometric records. In the DAP model, the shallow aquifer system overlying the Boom Clay is replaced by fixed head boundaries: this aquifer system is dominated by close-to-surface hydrological processes and the heads fluctuate seasonally without any apparent long-term trend. In the horizontal direction, the model extends to the south as far as the outcrops of the major aquitards: the Maldegem Formation confining the Ledo

  10. NASA's Pursuit of Low-Noise Propulsion for Low-Boom Commercial Supersonic Vehicles

    Science.gov (United States)

    Bridges, James; Brown, Clifford A.; Seidel, Jonathan A.

    2018-01-01

    Since 2006, when the Fundamental Aeronautics Program was instituted within NASA's Aeronautics Mission Directorate, there has been a Project looking at the technical barriers to commercial supersonic flight. Among the barriers is the noise produced by aircraft during landing and takeoff. Over the years that followed, research was carried out at NASA aeronautics research centers, often in collaboration with academia and industry, addressing the problem. In 2013, a high-level milestone was established, described as a Technical Challenge, with the objective of demonstrating the feasibility of a low-boom supersonic airliner that could meet current airport noise regulations. The Technical Challenge was formally called "Low Noise Propulsion for Low Boom Aircraft", and was completed in late 2016. This paper reports the technical findings from this Technical Challenge, reaching back almost 10 years to review the technologies and tools that were developed along the way. It also discusses the final aircraft configuration and propulsion systems required for a supersonic civilian aircraft to meet noise regulations using the technologies available today. Finally, the paper documents the model-scale tests that validated the acoustic performance of the study aircraft.

  11. Testing the Deployment Repeatability of a Precision Deployable Boom Prototype for the Proposed SWOT Karin Instrument

    Science.gov (United States)

    Agnes, Gregory S.; Waldman, Jeff; Hughes, Richard; Peterson, Lee D.

    2015-01-01

    NASA's proposed Surface Water Ocean Topography (SWOT) mission, scheduled to launch in 2020, would provide critical information about Earth's oceans, ocean circulation, fresh water storage, and river discharge. The mission concept calls for a dual-antenna Ka-band radar interferometer instrument, known as KaRIn, that would map the height of water globally along two 50 km wide swaths. The KaRIn antennas, which would be separated by 10 meters on either side of the spacecraft, would need to be precisely deployable in order to meet demanding pointing requirements. Consequently, an effort was undertaken to design build and prototype a precision deployable Mast for the KaRIn instrument. Each mast was 4.5-m long with a required dilitation stability of 2.5 microns over 3 minutes. It required a minimum first mode of 7 Hz. Deployment repeatability was less than +/- 7 arcsec in all three rotation directions. Overall mass could not exceed 41.5 Kg including any actuators and thermal blanketing. This set of requirements meant the boom had to be three times lighter and two orders of magnitude more precise than the existing state of the art for deployable booms.

  12. Sonic Boom.

    Science.gov (United States)

    Hurtig, Brent

    1998-01-01

    Reviews and evaluates Pro Tools 4.1, a multitrack digital audio workstation (DAWs) that imports and synchronizes to QuickTime or AVI digital movies. Audio-for-picture editors lock their digital audio workstations to linear videotape recorders, using complex, expensive time code synchronizers. Highlights Macintosh and Windows based alternatives.…

  13. A new and improved methodology for qualitative and quantitative mineralogical analysis of Boom Clay

    International Nuclear Information System (INIS)

    Zeelmaekers, E.; Vandenberghe, N.; Honty, M.; De Craen, M.; Derkowski, A.; Van Geet, M.

    2010-01-01

    Document available in extended abstract form only. A good knowledge of the mineralogy of any host formation studied for geological disposal of high-level radioactive waste, is a prerequisite for understanding the geochemical environment which will determine the migration and retention behaviour of radionuclides. In this respect, the Boom Clay mineralogical composition has been extensively studied last decades as reference host formation (e.g. ARCHIMEDEARGILE project, OECD-NEA clay catalogue report) with the aim to provide reliable data for a safety assessment. However, a comparison of the available literature data clearly showed a serious discrepancy among studies, not only in the quantitative, but also in the qualitative mineralogical composition of the Boom Clay (SAFIR II). The reason for such a huge disagreement could be related, among others, to variable grain size distributions of the studied samples (sample heterogeneity) and differences in the methodological approaches. In particular, the unambiguous characterisation of clay minerals and the quantification of mixed-layer phases appeared as an everlasting problem. This study is aimed at achieving a consensus on the qualitative and quantitative mineralogical data of the Boom Clay using the most advanced techniques currently available in the clay science. A new sampling campaign was performed in such a way that samples are (20 in total) more or less regularly distributed over Boom Clay Formation, ensuring that variations in the grain size distributions due to silty clay-clayey silt layers alternations are accounted for. The novel concept based on an analysis at two levels was applied: (1) bulk rock and (2) clay fraction analysis. (1) A bulk rock analysis consists of conventional XRD analysis with the identification of the principal mineral phases. As a next step, the bulk rock was mixed with a ZnO internal standard and experimental diffraction patterns of randomly oriented powders were analyzed using &apos

  14. Global Properties of M31’s Stellar Halo from the SPLASH Survey. III. Measuring the Stellar Velocity Dispersion Profile

    Science.gov (United States)

    Gilbert, Karoline M.; Tollerud, Erik; Beaton, Rachael L.; Guhathakurta, Puragra; Bullock, James S.; Chiba, Masashi; Kalirai, Jason S.; Kirby, Evan N.; Majewski, Steven R.; Tanaka, Mikito

    2018-01-01

    We present the velocity dispersion of red giant branch stars in M31’s halo, derived by modeling the line-of-sight velocity distribution of over 5000 stars in 50 fields spread throughout M31’s stellar halo. The data set was obtained as part of the Spectroscopic and Photometric Landscape of Andromeda’s Stellar Halo (SPLASH) Survey, and covers projected radii of 9 to 175 kpc from M31’s center. All major structural components along the line of sight in both the Milky Way (MW) and M31 are incorporated in a Gaussian Mixture Model, including all previously identified M31 tidal debris features in the observed fields. The probability that an individual star is a constituent of M31 or the MW, based on a set of empirical photometric and spectroscopic diagnostics, is included as a prior probability in the mixture model. The velocity dispersion of stars in M31’s halo is found to decrease only mildly with projected radius, from 108 km s‑1 in the innermost radial bin (8.2 to 14.1 kpc) to ∼80 to 90 km s‑1 at projected radii of ∼40–130 kpc, and can be parameterized with a power law of slope ‑0.12 ± 0.05. The quoted uncertainty on the power-law slope reflects only the precision of the method, although other sources of uncertainty we consider contribute negligibly to the overall error budget. The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

  15. Developments in modelling of thermohydro-geomechanical behaviour of Boom clay and clay-based buffer materials (volume 2)

    International Nuclear Information System (INIS)

    Baldi, G.; Hueckel, T.; Peano, A.; Pellegrini, R.

    1991-01-01

    This study is composed of two parts: The first part (Volume 1) lays the foundations of a comprehensive theoretical treatment of the interaction between water and soil skeleton during thermal dilatation. The second part (volume 2) is devoted to the development and the application of advance constitutive modelling of mechanical behaviour of clays taking into account the extensive tests of Boom clay reported in the first volume. The development concentrated on the improvement of prediction of the volumetric response of clay skeleton: (a) improving the dilatancy prediction at low to high overconsolidation ratios (Section 2). An elasto-plastic constitutive model has been developed to account for this effect (Section 3.2.); (b) modelling of swelling effects (Section 2.5). A preliminary interpretative model for swelling prediction has been developed (Section 2.5). The application part consisted in interpreting the experimental results obtained for Boom clay to calibrate a set of constants (Section 3) for performing numerical analyses (Section 4) for the thermomechanical model already calibrated for Boom clay (Appendix). Interpretation of the tests required an assessment of influence of the strong anisotropy effects revealed by Boom clay on the basis of an interpretative model characterized by a kinematic hardening plasticity and coupled elasticity (section 3)

  16. An Economic Rationale for the West African Scramble? The Commercial Transition and the Commodity Price Boom of 1835-1885

    NARCIS (Netherlands)

    Frankema, Ewout; Williamson, Jeffrey; Woltjer, Pieter

    2018-01-01

    We use a new trade dataset showing that nineteenth century Sub-Saharan Africa experienced a terms of trade boom comparable to other parts of the ‘global periphery’. A sharp rise in export prices in the five decades before the scramble (1835-1885) was followed by an equally impressive decline during

  17. Financial services in England in the late XVII century and first equity market boom (1691–1693

    Directory of Open Access Journals (Sweden)

    S.Z. Moshenskyi

    2016-09-01

    Full Text Available The article shows the formation of the British financial services industry in the 1690's and the reasons of the first joint-stock companies’ boom of 1691–1693's. The author describes the course of events of this boom, and data on the volume of transactions in shares. The reasons of the joint-stock boom end are associated with very low capitalization of most of the new companies. The consequence of rapid economic growth in England in the late XVII century was the appearance and rapid development of financial services. Financial intermediaries appeared first and their services, in particular the services of insurance companies, were in demand. The rapid increase in the number of insurance companies has become prerequisite for becoming financial capitalism that led to the emergence of other intermediaries which provided financial services. Among them there were the so-called "notaries" that offered a full range of services related to land transactions and "bankers, jewelers," that woke the first private bankers. Thus, in the early 1690's London had a favorable environment for the rapid growth of the financial market, which was the main precondition for expanding market shares and led to the joint-stock boom.

  18. Feasibility study on conducting overflight measurements of shaped sonic boom signatures using the Firebee BQM-34E RPV

    Science.gov (United States)

    Maglieri, Domenic J.; Sothcott, Victor E.; Keefer, Thomas N., Jr.

    1993-02-01

    A study was performed to determine the feasibility of establishing if a 'shaped' sonic boom signature, experimentally shown in wind tunnel models out to about 10 body lengths, will persist out to representative flight conditions of 200 to 300 body lengths. The study focuses on the use of a relatively large supersonic remotely-piloted and recoverable vehicle. Other simulation methods that may accomplish the objective are also addressed and include the use of nonrecoverable target drones, missiles, full-scale drones, very large wind tunnels, ballistic facilities, whirling-arm techniques, rocket sled tracks, and airplane nose probes. In addition, this report will also present a background on the origin of the feasibility study including a brief review of the equivalent body concept, a listing of the basic sonic boom signature characteristics and requirements, identification of candidate vehicles in terms of desirable features/availability, and vehicle characteristics including geometries, area distributions, and resulting sonic boom signatures. A program is developed that includes wind tunnel sonic boom and force models and tests for both a basic and modified vehicles and full-scale flight tests.

  19. The Perceived Work Ethic of K-12 Teachers by Generational Status: Generation X vs. Baby Boom Generation

    Science.gov (United States)

    Petty, Gregory C.

    2013-01-01

    This was an investigation of the work ethic of K-12 educators from Generation X and Baby Boomer generations. Teachers of the baby boom generation were born between 1946 and 1964, and many are beginning to retire. There is an impending teacher shortage due to the large numbers of this group retiring or leaving the profession. School administrators…

  20. Crane and Hoisting Equipment Operator Boom Truck Operator: Apprenticeship Course Outline. Apprenticeship and Industry Training. 34-305.2

    Science.gov (United States)

    Alberta Advanced Education and Technology, 2005

    2005-01-01

    The graduate of the Crane and Hoisting Equipment Operator Boom Truck Operator apprenticeship program is a certified journeyperson who will be able to: (1) responsibly do all work tasks expected of a journeyperson; (2) correctly use and care for tools and materials which are required to carry out the normal service and maintenance of the machines…

  1. Subjective loudness and annoyance of filtered N-wave sonic booms.

    Science.gov (United States)

    Niedzwiecki, A; Ribner, H S

    1979-03-01

    The contribution of the "infrasonic" low-frequency content of sonic boom N waves to subjective loudness and annoyance has been investigated. An extended low-frequency response loudspeaker-driven simulation booth was employed, with computer-generated input test signals. For test N waves of 1 ms rise time and 150 ms duration, frequencies below 25 and 50 Hz, respectively, were cut off by digital filters simulating simple RC circuits. The filtered signal amplitude was adjusted versus the amplitude (48 Pa) of a reference unfiltered N wave (effective low-frequency cutoff approximately 0.1 Hz) until the two sounded equally loud (first experiment) or equally annoying (second experiment). The amplitude differences for equality were very slight: less than 0.6 dB at most. Surprisingly, while loss of the low frequencies slightly decreased the loudness, it slightly increased the annoyance.

  2. Evaluation of oxidation of Boom Clay during construction and operation of a radioactive waste repository

    International Nuclear Information System (INIS)

    Van Geet, M.

    2007-01-01

    Within the Sixth Framework Programme bey the European Commission, NF-PRO is an Integrated Project on the key-processes and their couplings in the near-field of a repository for the geological disposal of vitrified high-level radioactive waste and spent fuel. For the construction and operation of a geological repository of radioactive waste, the excavation and ventilation of galleries is necessary. As such, the oxidation of the anaerobic host rock, containing pyrite, is unavoidable. This chemical perturbation can affect the favourable host rock characteristics and influence the engineered barrier system. The aim of this study is to evaluate the extent of oxidation in the Boom Clay related to excavation of galleries; the evolution of the extent of oxidation during ventilation of galleries. The latter aspect might deliver important input towards design, especially concerning the time to leave galleries open. Some valuable information towards performance assessment can be given as well

  3. Étude du comportement anisotrope de l'argile de Boom

    OpenAIRE

    DAO, Linh Quyen

    2015-01-01

    Dans le cadre de la déposition géologique profonde des déchets radioactifs, l'argile de Boom est choisie comme une des formations hôtes potentielles dans le programme belge. Par sa formation géologique, cette argile est considérée comme un matériau isotrope transversal. En effet, l'anisotropie de ses propriétés hydraulique et thermique a été mise en évidence dans plusieurs études. Il apparait maintenant nécessaire de mener une étude complète sur son comportement anisotrope. Sur le plan expéri...

  4. Analysis of Offshore Knuckle Boom Crane - Part One: Modeling and Parameter Identification

    Directory of Open Access Journals (Sweden)

    Morten K. Bak

    2013-10-01

    Full Text Available This paper presents an extensive model of a knuckle boom crane used for pipe handling on offshore drilling rigs. The mechanical system is modeled as a multi-body system and includes the structural flexibility and damping. The motion control system model includes the main components of the crane's electro-hydraulic actuation system. For this a novel black-box model for counterbalance valves is presented, which uses two different pressure ratios to compute the flow through the valve. Experimental data and parameter identification, based on both numerical optimization and manual tuning, are used to verify the crane model. The demonstrated modeling and parameter identification techniques target the system engineer and takes into account the limited access to component data normally encountered by engineers working with design of hydraulic systems.

  5. [Cigarette and advertising poster: history of a dangerous connection in the post-war economic boom].

    Science.gov (United States)

    Olivier, Jacques

    2013-11-27

    The advertising poster's main characteristic is the ability to convey a commercial message quickly and publicly thanks to its straightforward image and text. The young people, being the tobacco industry's principal target, are particularly exposed to these messages. This kind of advertisement becomes a mean of counterstroke as soon as the cigarette's harmfulness is acknowledged. Some of the cigarette industry's strategies can be revealed by the historical analysis of a 253 posters corpus selected among the main cigarette manufacturers in Switzerland at the time of the post-war economic boom. With the misuse of sport's theme, the overvaluation of the filter's efficiency, the use of a vocabulary that implies lightness and by erasing the image of smoke in its advertisement, the industry tries to reassure the smoker wrongly.

  6. Booming Development of Group IV-VI Semiconductors: Fresh Blood of 2D Family.

    Science.gov (United States)

    Zhou, Xing; Zhang, Qi; Gan, Lin; Li, Huiqiao; Xiong, Jie; Zhai, Tianyou

    2016-12-01

    As an important component of 2D layered materials (2DLMs), the 2D group IV metal chalcogenides (GIVMCs) have drawn much attention recently due to their earth-abundant, low-cost, and environmentally friendly characteristics, thus catering well to the sustainable electronics and optoelectronics applications. In this instructive review, the booming research advancements of 2D GIVMCs in the last few years have been presented. First, the unique crystal and electronic structures are introduced, suggesting novel physical properties. Then the various methods adopted for synthesis of 2D GIVMCs are summarized such as mechanical exfoliation, solvothermal method, and vapor deposition. Furthermore, the review focuses on the applications in field effect transistors and photodetectors based on 2D GIVMCs, and extends to flexible devices. Additionally, the 2D GIVMCs based ternary alloys and heterostructures have also been presented, as well as the applications in electronics and optoelectronics. Finally, the conclusion and outlook have also been presented in the end of the review.

  7. Evaluation of Grid Modification Methods for On- and Off-Track Sonic Boom Analysis

    Science.gov (United States)

    Nayani, Sudheer N.; Campbell, Richard L.

    2013-01-01

    Grid modification methods have been under development at NASA to enable better predictions of low boom pressure signatures from supersonic aircraft. As part of this effort, two new codes, Stretched and Sheared Grid - Modified (SSG) and Boom Grid (BG), have been developed in the past year. The CFD results from these codes have been compared with ones from the earlier grid modification codes Stretched and Sheared Grid (SSGRID) and Mach Cone Aligned Prism (MCAP) and also with the available experimental results. NASA's unstructured grid suite of software TetrUSS and the automatic sourcing code AUTOSRC were used for base grid generation and flow solutions. The BG method has been evaluated on three wind tunnel models. Pressure signatures have been obtained up to two body lengths below a Gulfstream aircraft wind tunnel model. Good agreement with the wind tunnel results have been obtained for both on-track and off-track (up to 53 degrees) cases. On-track pressure signatures up to ten body lengths below a Straight Line Segmented Leading Edge (SLSLE) wind tunnel model have been extracted. Good agreement with the wind tunnel results have been obtained. Pressure signatures have been obtained at 1.5 body lengths below a Lockheed Martin aircraft wind tunnel model. Good agreement with the wind tunnel results have been obtained for both on-track and off-track (up to 40 degrees) cases. Grid sensitivity studies have been carried out to investigate any grid size related issues. Methods have been evaluated for fully turbulent, mixed laminar/turbulent and fully laminar flow conditions.

  8. Make a Splash with Penguins.

    Science.gov (United States)

    Fox, Helen

    1989-01-01

    Several across-the-curriculum activities, with a penguin theme, are described. Research, discussion, science, writing, math, and art activities are listed. Included is a list of resources which gives sources for books and posters. (IAH)

  9. Gas fluxing of aluminum: a bubble probe for optimization of bubbles/bubble distribution and minimization of splashing/droplet formation

    International Nuclear Information System (INIS)

    James W. Evans; Auitumn Fjeld

    2006-01-01

    totaling 1.549 million lbs. for only thirteen of the twenty three primary smelters then in operation in the US. The research work described in the body of this report (the doctoral dissertation of Dr. Autumn M. Fjeld) had as its objective the improvement of gas fluxing technology to reduce emissions while still maintaining fluxing unit metal throughput. A second objective was a better understanding of the splashing and droplet emission that occurs during fluxing at high gas throughput rates. In the extreme such droplets can form undesired accretions on the walls and gas exit lines of the fluxing unit. Consequently, the productivity of a fluxing unit is sometimes limited by the need to avoid such spraying of droplets produced as gas bubbles break at the metal surface. The approach used was a combination of experimental work in laboratories at UC Berkeley and at the Alcoa Technical Center. The experimental work was mostly on a bubble probe that could be used to determine the extent of dispersion of gas bubbles in the fluxing unit (a parameter affecting the utilization of the injected chlorine). Additionally a high speed digital movie camera was used to study droplet formation due to gas bubbles bursting at the surface of a low melting point alloy. The experimental work was supported by mathematical modeling. In particular, two FLUENT? base mathematical models were developed to compute the metal flow and distribution of the gas within a fluxing unit. Results from these models were then used in a third model to compute emissions and the progress of impurity removal as a function of parameters such as rotor speed. The project was successful in demonstrating that the bubble probe could detect bubbles in a gas fluxing unit at the Alcoa technical Center outside Pittsburgh, PA. This unit is a commercial sized one and the probe, with its associated electronics, was subjected to the hostile molten aluminum, electrical noise etc. Despite this the probes were, on several occasions

  10. Manoeuverability analysis for direct casting spreaders with non-slewable discharge boom. Manoevrierbarkeitsanalyse fuer Direktversturzabsetzer mit nicht schwenkbarem Abwurfausleger

    Energy Technology Data Exchange (ETDEWEB)

    Korzen, Z.; Twarog, W. (Politechnika Wroclawska (Poland))

    1990-06-01

    The authors discuss the problems involved when manoeuvering direct casting spreaders that are equipped with a rigid discharge boom. The crawler-mounted travel gear of this type of large machine consists of three independently steered pairs of crawlers. In the analysis all the possible rational geometrical forms of travel tracks with straight and curved sections are determined which are necessary in order to manoeuver such machines and must fulfil certain requirements. For track sections in which it is essential that as little energy as possile should be used in order to shift the centre of gravity of the machine as desired, analytic relations were determined for the numerical evaluation of the necessary manoeuvering space and for an analysis of the extreme values of the kinematic parameters of the discharge boom during manoeuvering. Finally, an example is presented which illustrates the practical application of the proposed analytic formulae. (orig.).

  11. Low-Speed Control of Heavy-Load Transfer Robot with Long Telescopic Boom Based on Stribeck Friction Model

    Directory of Open Access Journals (Sweden)

    Bo You

    2012-01-01

    Full Text Available The severe low-speed creep phenomenon occurs in the telescopic boom system of a heavy-load transfer robot with a long telescopic boom as a result of nonlinear friction. In order to improve control precision and operation performance at low speeds, we built a three-loop control nonlinear model of an AC servo motor with Stribeck friction disturbance. Traditional proportional-integral-derivative controller (PID and fuzzy PID controls were, respectively, adopted in the position loop, and the control performance was simulated. The results showed that a system with fuzzy PID control eliminates “flat top” position tracking and “dead zone” speed tracking, which are generated by traditional PID, and thereby decreases the effect of friction on the performance of the servo system. This elimination also improved the tracking accuracy and robustness of the system.

  12. Technetium migration in Boom Clay - Assessing the role of colloid-facilitated transport in a deep clay formation

    International Nuclear Information System (INIS)

    Bruggeman, C.; Martens, E.; Maes, N.; Jacops, E.; Van Gompel, M.; Van Ravestyn, L.

    2010-01-01

    Document available in extended abstract form only. The role of colloids - mainly dissolved natural organic matter (NOM, 50-150 mg/l) - in the transport of radionuclides in the Boom Clay formation (Mol, Belgium), has long since been a matter of (heavy) debate. For more than 20 years, batch experiments with Boom Clay suspensions showed a pronounced influence of the dissolved organic carbon concentration on the aqueous concentrations of different radionuclides like Tc, Np, Am and U. Moreover, small fractions of these radionuclides were also observed to elute almost un-retarded out of confined clay cores in percolation experiments. In the past years, a new conceptual model for the speciation of the long-lived fission product Technetium- 99 ( 99 Tc) under Boom Clay conditions has been drafted. In brief, the stable oxidation state of 99 Tc in these conditions is +IV, and, therefore, Tc solution concentrations are limited by the solubility of TcO 2 .nH 2 O(s). However, during reduction of TcVII (in the TcO 4 - form) to TcIV, precursor TcO 2 .nH 2 O colloids are formed, which are stabilised by the dissolved organic matter present in Boom Clay interstitial pore water, and in supernatants of Boom Clay batch suspensions. Moreover, this stabilisation process occurs in such a systematic way, that (conditional) interaction constants could be established, and the behaviour was described as a 'hydrophobic sorption', or, more accurately, a 'colloid-colloid' interaction. This conceptual model was implemented into PHREEQC geochemical and Hydrus transport code to come to a reactive transport model that was used to simulate both the outflow and the tracer profile in several long-term running percolation experiments (both in lab and under in situ conditions). To account for slow dissociation kinetics of Tc from the NOM colloid, a first-order kinetic rate equation was also added to the model. In order to describe the migration of colloidal particles (NOM), an

  13. The Baby Boom As It Ages: How Has It Affected Patterns of Consumptions and Savings in the United States?

    OpenAIRE

    Diane Macunovich

    1999-01-01

    Using detailed estimates of personal consumption expenditures at the state level for 1900, 1929, 1970, and 1982 developed by Stanley Lebergott, this paper demonstrates that the passage of the Baby Boom from childhood through the teen years and into family formation would have caused market swings in patterns of aggregate consumption and savings in the United States during the past 50 years. The effect of age structure on personal consumption expenditures is estimated using population by singl...

  14. A reversal of the socioeconomic gradient of nuptiality during the Swedish mid-20th-century baby boom

    Directory of Open Access Journals (Sweden)

    Glenn Sandström

    2017-11-01

    Full Text Available Background: Research into the causes of the mid-20th-century baby boom has concluded that the main proximate cause of the fertility increase during the 1940s was earlier and more universal marriage in the cohorts born after 1910, and that this association between nuptiality trends and fertility was particularly strong in Sweden. Objective: However, we do not know whether this was a general trend or if certain socioeconomic groups spearheaded the change toward earlier marriage. Methods: The present study uses event history analysis to investigate the marital histories of approximately 100,000 men and women in Sweden, born 1880-1934, to determine how socioeconomic differentials in nuptiality developed during the period 1900-1960. Conclusions: The analysis shows that the sharp increase in nuptiality was not driven uniformly across different social strata, but rather took the form of earlier and more universal marriage among men in the mid and upper social strata and among economically active women, while male unskilled workers and women outside the labor market did not participate in the nuptiality boom during the peak baby boom years and even showed some signs of decreased marriage probabilities compared to earlier cohorts. Contribution: The results indicate that sector-specific economic growth after the depression and the breakthrough of the Swedish welfare state benefitted couples who could aspire to a middle-class identity, and that pronatalist policies made female economic activity more compatible with marriage. The results show that the shift toward a positive female socioeconomic gradient of marriage and family formation that can be observed in contemporary Sweden had its beginnings already with the cohorts that participated in the mid-20th-century baby boom.

  15. Low sonic-boom design of a silent supersonic technology demonstrator: Development of CAPAS and its application

    OpenAIRE

    Makino, Yoshikazu; 牧野 好和

    2007-01-01

    Aerodynamic design system developed in JAXA SST (SuperSonic Transport) project are summarized and a newly developed aerodynamic design system CAPAS (CAD (Computer Aided Design)-based Automatic Panel Analysis System) is introduced in this paper. The CAPAS utilizes the CATIA (Computer Aided Three dimensional Interactive Application) v4 to define an airplane configuration and the A502 panel method for aerodynamic analysis and the Thomas code for sonic-boom analysis. The CAPAS has a java-based GU...

  16. Extractive Industries and Local Development in the Peruvian Highlands: Socio-Economic Impacts of the Mid-1990s Mining Boom

    OpenAIRE

    Elisa Ticci

    2011-01-01

    Since the late Nineties, the mining sector in Peru has been experiencing a protracted period of rapid growth. This paper investigates local impacts of the mining boom on migration, on access to basic services, on labour market and on occupational distribution across sectors. By applying propensity score matching technique, mining and non-mining districts are compared. The results show that recent mining expansion has encouraged migration inflows to mining districts and affected th...

  17. NASA's Advanced Solar Sail Propulsion System for Low-Cost Deep Space Exploration and Science Missions that Use High Performance Rollable Composite Booms

    Science.gov (United States)

    Fernandez, Juan M.; Rose, Geoffrey K.; Younger, Casey J.; Dean, Gregory D.; Warren, Jerry E.; Stohlman, Olive R.; Wilkie, W. Keats

    2017-01-01

    Several low-cost solar sail technology demonstrator missions are under development in the United States. However, the mass saving derived benefits that composites can offer to such a mass critical spacecraft architecture have not been realized yet. This is due to the lack of suitable composite booms that can fit inside CubeSat platforms and ultimately be readily scalable to much larger sizes, where they can fully optimize their use. With this aim, a new effort focused at developing scalable rollable composite booms for solar sails and other deployable structures has begun. Seven meter booms used to deploy a 90 m2 class solar sail that can fit inside a 6U CubeSat have already been developed. The NASA road map to low-cost solar sail capability demonstration envisioned, consists of increasing the size of these composite booms to enable sailcrafts with a reflective area of up to 2000 m2 housed aboard small satellite platforms. This paper presents a solar sail system initially conceived to serve as a risk reduction alternative to Near Earth Asteroid (NEA) Scout's baseline design but that has recently been slightly redesigned and proposed for follow-on missions. The features of the booms and various deployment mechanisms for the booms and sail, as well as ground support equipment used during testing, are introduced. The results of structural analyses predict the performance of the system under microgravity conditions. Finally, the results of the functional and environmental testing campaign carried out are shown.

  18. Natural Resources Management: The Effect of the Commodity Boom on Indonesia’s Industrial Development and Welfare

    Directory of Open Access Journals (Sweden)

    Maria Monica Wihardja

    2016-03-01

    Full Text Available The end of the commodity boom in 2012 once again exposed Indonesia to the vulnerability of the commodity price shocks. This article reviews how Indonesia managed its natural resources in 2001–12 and when the commodity boom ends. What are the lessons learned? Indonesia’s experience is similar to that of other countries rich in natural resources, including the crowding-out of non-commodity sectors, protectionist trade regimes, fiscal inefficiency, slow skill accumulation, rising inequality and environmental damages. In the aftermath of the global financial crisis of 2008–09, the early trade -policy response at the end of the commodity boom is inward-looking and protective of domestic markets and industries and aims to increase the added value of commodities by downstreaming. This trend is clearly reflected in the 2014 Trade Law, the 2014 Industry Law and the mineral export ban, which was introduced in 2009 through the 2009 Law on Mining of Coal and Minerals and took effect in 2014. Indonesia should learn from other countries in managing its resource revenues, such as through a commodity fund designed to fit its domestic specificity. Reindustrializing, increasing agricultural productivity beyond palm oil and tapping the country’s potential in the services sector including tourism and creative industries are also necessary to promote diversification in production and trade. Resource management policy should also include stronger environmental regulations.

  19. Simulations of sonic boom ray tube area fluctuations for propagation through atmospheric turbulence including caustics via a Monte Carlo method

    Science.gov (United States)

    Sparrow, Victor W.; Pierce, Allan D.

    1992-01-01

    A theory which gives statistical predictions for how often sonic booms propagating through the earth's turbulent boundary layer will encounter caustics, given the spectral properties of the atmospheric turbulence, is outlined. The theory is simple but approximately accounts for the variation of ray tube areas along ray paths. This theory predicts that the variation of ray tube areas is determined by the product of two similar area factors, psi (x) and phi (x), each satisfying a generic harmonic oscillator equation. If an area factor increases the peak acoustic pressure decreases, and if the factor decreases the peak acoustic pressure increases. Additionally, if an area factor decreases to zero and becomes negative, the ray has propagated through a caustic, which contributes a phase change of 90 degrees to the wave. Thus, it is clear that the number of times that a sonic boom wave passes through a caustic should be related to the distorted boom waveform received on the ground. Examples are given based on a characterization of atmospheric turbulence due to the structure function of Tatarski as modified by Crow.

  20. Modelling of radionuclide migration and heat transport from an High-Level-Radioactive-Waste-repository (HLW) in Boom clay

    International Nuclear Information System (INIS)

    Put, M.; Henrion, P.

    1992-01-01

    For the modelling of the migration of radionuclides in the Boom clay formation, the analytical code MICOF has been updated with a 3-dimensional analytical solution for discrete sources. the MICOF program is used for the calculation of the release of α and β emitters from the HIGH LEVEL RADIOACTIVE WASTES (HLW). A coherent conceptual model is developed which describes all the major physico-chemical phenomena influencing the migration of radionuclides in the Boom clay. The concept of the diffusion accessible porosity is introduced and included in the MICOF code. Different types of migration experiments are described with their advantages and disadvantages. The thermal impact of the HLW disposal in the stratified Boom clay formation has been evaluated by a finite element simulation of the coupled heat and mass transport equation. The results of the simulations show that under certain conditions thermal convection cells may form, but the convective heat transfer in the clay formation is negligible. 6 refs., 19 figs., 2 tabs., 5 appendices

  1. Summary of Propagation Cases of the Second AIAA Sonic Boom Prediction Workshop

    Science.gov (United States)

    Rallabhandi, Sriram; Loubeau, Alexandra

    2017-01-01

    A summary is provided for the propagation portion of the second AIAA Sonic Boom Workshop held January 8, 2017 in conjunction with the AIAA SciTech 2017 conference. Near-field pressure waveforms for two cases were supplied and ground signatures at multiple azimuthal angles as well as their corresponding loudness metrics were requested from 10 participants, representing 3 countries. Each case had some required runs, as well as some optional runs. The required cases included atmospheric profiles with measured data including winds, using Radiosonde balloon data at multiple geographically spread locations, while the optional cases included temperature and pressure profiles from the US Standard atmosphere. The humidity profiles provided for the optional cases were taken from ANSI guidance, as the authors were unaware of an accepted standard at the time the cases were released to the participants. Participants provided ground signatures along with the requested data, including some loudness metrics using their best practices, which included lossy as well as lossless schemes. All the participants' submissions, for each case, are compared and discussed. Noise or loudness measures are calculated and detailed comparisons and statistical analyses are performed and presented. It has been observed that the variation in the loudness measures and spread between participants' submissions increased as the computation proceeded from under-track locations towards the lateral cut-off. Lessons learned during this workshop are discussed and recommendations are made for potential improvements and possible subsequent workshops as we collectively attempt to refine our analysis methods.

  2. Nearfield Summary and Statistical Analysis of the Second AIAA Sonic Boom Prediction Workshop

    Science.gov (United States)

    Park, Michael A.; Nemec, Marian

    2017-01-01

    A summary is provided for the Second AIAA Sonic Boom Workshop held 8-9 January 2017 in conjunction with AIAA SciTech 2017. The workshop used three required models of increasing complexity: an axisymmetric body, a wing body, and a complete configuration with flow-through nacelle. An optional complete configuration with propulsion boundary conditions is also provided. These models are designed with similar nearfield signatures to isolate geometry and shock/expansion interaction effects. Eleven international participant groups submitted nearfield signatures with forces, pitching moment, and iterative convergence norms. Statistics and grid convergence of these nearfield signatures are presented. These submissions are propagated to the ground, and noise levels are computed. This allows the grid convergence and the statistical distribution of a noise level to be computed. While progress is documented since the first workshop, improvement to the analysis methods for a possible subsequent workshop are provided. The complete configuration with flow-through nacelle showed the most dramatic improvement between the two workshops. The current workshop cases are more relevant to vehicles with lower loudness and have the potential for lower annoyance than the first workshop cases. The models for this workshop with quieter ground noise levels than the first workshop exposed weaknesses in analysis, particularly in convective discretization.

  3. Cart3D Simulations for the First AIAA Sonic Boom Prediction Workshop

    Science.gov (United States)

    Aftosmis, Michael J.; Nemec, Marian

    2014-01-01

    Simulation results for the First AIAA Sonic Boom Prediction Workshop (LBW1) are presented using an inviscid, embedded-boundary Cartesian mesh method. The method employs adjoint-based error estimation and adaptive meshing to automatically determine resolution requirements of the computational domain. Results are presented for both mandatory and optional test cases. These include an axisymmetric body of revolution, a 69deg delta wing model and a complete model of the Lockheed N+2 supersonic tri-jet with V-tail and flow through nacelles. In addition to formal mesh refinement studies and examination of the adjoint-based error estimates, mesh convergence is assessed by presenting simulation results for meshes at several resolutions which are comparable in size to the unstructured grids distributed by the workshop organizers. Data provided includes both the pressure signals required by the workshop and information on code performance in both memory and processing time. Various enhanced techniques offering improved simulation efficiency will be demonstrated and discussed.

  4. Construction of an underground facility for ''in-situ'' experimentation in the boom clay

    International Nuclear Information System (INIS)

    Bonne, A.; Manfroy, P.; Van Haelewijn, R.; Heremans, R.

    1985-01-01

    The Belgian R and D Programme concerning the disposal of high-level and alpha-bearing radioactive waste in continental geological formations was launched by SCK/CEN, Mol in 1974. The programme is characterised by its site and formation specific approach, i.e. Mol and Boom clay. In the framework of site confirmation, an important issue is the ''in situ'' experimentation which should allow to determine with a higher degree of confidence the numerical value of the data needed for the evaluations, assessments and designs. The present report deals with the construction of an underground experimental facility, which was scheduled to be fully completed in mid 1984. Initially, the completion was scheduled for the end of 1983, but supplementary experiments related to geomechanics and mining capabilities and to be performed during the construction phase of the experimental facility delayed the completion of the underground facility. During the construction, a continuous observation was made of the behaviour of the clay mass and the structures. In this final contract-report, only the as-built structure, the time schedule and the ''in situ'' experiments launched or performed during the construction phase are dealt with

  5. Lifecycle effects of a recession on health behaviors: Boom, bust, and recovery in Iceland.

    Science.gov (United States)

    Ásgeirsdóttir, Tinna Laufey; Corman, Hope; Noonan, Kelly; Reichman, Nancy E

    2016-03-01

    This study uses individual-level longitudinal data from Iceland, a country that experienced a severe economic crisis in 2008 and substantial recovery by 2012, to investigate the extent to which the effects of a recession on health behaviors are lingering or short-lived and to explore trajectories in health behaviors from pre-crisis boom, to crisis, to recovery. Health-compromising behaviors (smoking, heavy drinking, sugared soft drinks, sweets, fast food, and tanning) declined during the crisis, and all but sweets continued to decline during the recovery. Health-promoting behaviors (consumption of fruit, fish oil, and vitamins/minerals and getting recommended sleep) followed more idiosyncratic paths. Overall, most behaviors reverted back to their pre-crisis levels or trends during the recovery, and these short-term deviations in trajectories were probably too short-lived in this recession to have major impacts on health or mortality. A notable exception is for binge drinking, which declined by 10% during the 2 crisis years, continued to fall (at a slower rate of 8%) during the 3 recovery years, and did not revert back to the upward pre-crisis trend during our observation period. These lingering effects, which directionally run counter to the pre-crisis upward trend in consumption and do not reflect price increases during the recovery period, suggest that alcohol is a potential pathway by which recessions improve health and/or reduce mortality. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Organic matter linked radionuclide transport in Boom clay - Phenomenological understanding and abstraction to PA

    International Nuclear Information System (INIS)

    Maes, N.; Bruggeman, C.; Liu, D.J.; Salah, S.; Van Laer, L.; Wang, L.; Weetjens, E.; Govaerts, J.; Marivoet, J.; Brassinnes, S.

    2012-01-01

    Document available in extended abstract form only. In the frame of the Belgian research program on long term management of high-level and/or long-lived radioactive wastes coordinated by ONDRAF/NIRAS, plastic clays (i.e., Boom Clay and Ypresian clays) are investigated for their potential to host a deep geological disposal repository for radioactive waste because of, among others, their ability to significantly retard radionuclide releases to the biosphere. The Boom Clay is characterised by the presence of a relatively high amount of dissolved organic matter (DOM, humic substances) which show a strong interaction with a suite of radionuclides (RN) like lanthanides, actinides and transition metals. This interaction with DOM leads in general to an increased mobility of the radionuclide as the OM can act as a colloidal carrier for the radionuclide. Therefore, the quantification and the understanding of the underlying processes are needed for the demonstration of confidence in the host formation to act as a suitable barrier. However, this is not an easy task, given the multitude of processes involved: complexation/colloid formation, sorption, kinetics, filtration, -. In this presentation, we will provide an overview of the research work that leads to a straightforward reactive transport model capturing fairly well the experimental observations. The model can be considered as an intermediate model providing a good basis for further safety abstraction on the one hand and the way to a more detailed phenomenological understanding on the other hand. The research is focussed on the underlying processes that govern speciation, sorption and transport. These underlying processes are investigated in a bottom-up approach, from simple systems to more complex systems. Interpretation is done using thermodynamic based models. Whereas the contribution of Bruggeman et al. focusses mainly on (batch) sorption studies (of trivalent RN), this presentation will provide more details on the

  7. Boom or bust : developing countries' rough ride on the commodity price rollercoaster

    International Nuclear Information System (INIS)

    Brown, O.; Gibson, J.

    2006-10-01

    Current high commodity prices are driven by strong demand from the emerging economies of China and India in addition to high consumption in the United States. Many developing countries are experiencing massive windfall revenues from high commodity prices. However, commodity prices are highly volatile in the short term, and can vary as much as 50 per cent in a single year. While developed country producers are supported by subsidies and social safety nets, developing countries and smallholder producers feel the extent of commodity price volatility more directly. Many developing countries are becoming locked into the production and export of primary commodities whose volatile prices are declining over the long term, and over which they have very little control. Price volatility makes sound fiscal planning difficult for both countries and producers. Price booms and busts also drive social inequalities, livelihood inequalities, and corruption. Price swings can cause conflict over valuable land and resources, and does not create incentives for sound environmental stewardship. This paper described the impacts of commodity price volatility in developing countries with the aim of promoting discussion about what can be done to help stabilize revenues for countries as well as producers. Price trends and their importance were reviewed, and the theoretical benefits of liberalized commodity markets were examined. Previous attempts to stabilize commodity prices were reviewed. It was concluded that the best long-term solution to the commodity price problem is economic diversification. Recommendations for promoting economic diversification were provided. 43 refs., 1 tab., 2 figs

  8. Experimental evaluation of the hydraulic resistance of compacted bentonite/boom clay interface

    International Nuclear Information System (INIS)

    Tang, Anh-Minh; Cui, Yu-Jun; Delage, Pierre; Munoz, Juan Jorge; Li, Xiang-Ling

    2008-01-01

    In the framework of the in-situ PRACLAY Heater experiment to be performed in the HADES URF in Mol (Belgium), the feasibility of a hydraulic cut-off of the Excavation Damaged Zone (EDZ) and the Repository Components (RC) of the disposal galleries by using a horizontal seal will be examined. It has been planned to install an annular seal composed of compacted bentonite between the heated zone and the access gallery (PRACLAY seal test), so that to avoid any hydraulic shortcut towards the access gallery. According to numerical scoping calculations, heating until 80 deg C will induce a pore pressure of the order of 3.0 MPa. In order to verify the effects of this water pressure on the performance of the annular seal system and more specifically on the hydraulic resistance of the interface between the compacted bentonite and the host rock (Boom clay), laboratory percolation tests at 20 and 80 deg C were performed. The results confirm the performance of the compacted bentonite seal to avoid the hydraulic shortcut to the access gallery under the foreseen hydraulic and thermal conditions. (author)

  9. Booming Development of Group IV–VI Semiconductors: Fresh Blood of 2D Family

    Science.gov (United States)

    Zhou, Xing; Zhang, Qi; Gan, Lin; Li, Huiqiao; Xiong, Jie

    2016-01-01

    As an important component of 2D layered materials (2DLMs), the 2D group IV metal chalcogenides (GIVMCs) have drawn much attention recently due to their earth‐abundant, low‐cost, and environmentally friendly characteristics, thus catering well to the sustainable electronics and optoelectronics applications. In this instructive review, the booming research advancements of 2D GIVMCs in the last few years have been presented. First, the unique crystal and electronic structures are introduced, suggesting novel physical properties. Then the various methods adopted for synthesis of 2D GIVMCs are summarized such as mechanical exfoliation, solvothermal method, and vapor deposition. Furthermore, the review focuses on the applications in field effect transistors and photodetectors based on 2D GIVMCs, and extends to flexible devices. Additionally, the 2D GIVMCs based ternary alloys and heterostructures have also been presented, as well as the applications in electronics and optoelectronics. Finally, the conclusion and outlook have also been presented in the end of the review. PMID:27981008

  10. Central and Eastern Europe After the Boom - Time for a Stragegy Change for Foreign Multinationals?

    Directory of Open Access Journals (Sweden)

    Arnold Schuh

    2013-06-01

    Full Text Available In 2008 the global financial and economic crisis ended a six-year-long boom period with an average growth rate well above 5% in Central and Eastern Europe (CEE. Although not the originators of the crisis some CEE countries such as the Baltic States and Ukraine were among the worst hit by this economic downturn. The crisis did not only shatter the financial markets, banks and the real economy but also the growth image of CEE. The huge market potential and expected higher growth rates resulting from the catching-up process to West European standards have been the main reason for the flood of foreign direct investments into the countries of the region in the two decades before. Suddenly, foreign direct investors were confronted with stalled and even collapsing market growth, shrinking disposable household income, business customers and partners on the verge of bankruptcy and no real sign of a quick recovery. While the situation improved a little in 2011, the economic outlook and the sentiment of foreign investors have remained gloomy, at least for parts of the region. It is obvious that when faced with such a huge economic downturn companies stop geographic expansion and put the brakes on investments.

  11. Supply of the numerical simulation for the evaluation of the sonic boom of meteorites

    International Nuclear Information System (INIS)

    Henneton, Martin

    2013-01-01

    Within the framework of the Comprehensive Nuclear-Test-Ban Treaty, infra-sound is one survey technique monitoring nuclear explosions. These ones have to be distinguished from natural sources of infra-sound like atmospheric meteorite entries. With a view to investigate meteorites as an infra-sound source, finite volume simulations of the hypersonic flow are performed at sufficiently far distances to reach the acoustic regime. They are then matched to a nonlinear ray tracing method to propagate the signal within the atmosphere down to the ground. For perfect gases, this approach allows us to validate the theoretical model based on simplifying assumptions. More realistic simulations in real gases at thermochemical equilibrium, show a major modification of the pressure field in the near field but a moderate influence for infra-sound at the ground level. Numerical results are compared to infra-sound and seismic measurements in the case of the well-documented meteorite of Carancas (Peru, 2007). This confrontation highlights a good agreement for the spectrum of the waveform but a large overestimation of the overpressure at receptors located near the impact crater. This study also allowed us to propose a new entry trajectory for the meteorite, and to identify one of the recorded signals as a sonic boom. (author) [fr

  12. Is it 'boom times' for baleen whales in the Pacific Arctic region?

    Science.gov (United States)

    Moore, Sue E

    2016-09-01

    The marine ecosystem in the Pacific Arctic region has experienced dramatic transformation, most obvious by the loss of sea ice volume (75%), late-summer areal extent (50%) and change in phenology (four to six weeks longer open-water period). This alteration has resulted in an opening of habitat for subarctic species of baleen whales, many of which are recovering in number from severe depletions from commercial whaling in the nineteenth and twentieth centuries. Specifically, humpback, fin and minke whales (Megaptera novaeangliae, Balaenoptera physalus and Balaenoptera acutorostrata) are now regularly reported during summer and autumn in the southern Chukchi Sea. These predators of zooplankton and forage fishes join the seasonally resident grey whale (Eschrichtius robustus) and the arctic-endemic bowhead whale (Balaena mysticetus) in the expanding open-ocean habitat of the Pacific Arctic. Questions arising include: (i) what changes in whale-prey production and delivery mechanisms have accompanied the loss of sea ice, and (ii) how are these five baleen whale species partitioning the expanding ice-free habitat? While there has been no programme of research specifically focused on these questions, an examination of seasonal occurrence, foraging plasticity and (for bowhead whales) body condition suggests that the current state of Pacific Arctic marine ecosystem may be 'boom times' for baleen whales. These favourable conditions may be moderated, however, by future shifts in ecosystem structure and/or negative impacts to cetaceans related to increased commercial activities in the region. © 2016 The Author(s).

  13. Doom and boom on a resilient reef: climate change, algal overgrowth and coral recovery.

    Science.gov (United States)

    Diaz-Pulido, Guillermo; McCook, Laurence J; Dove, Sophie; Berkelmans, Ray; Roff, George; Kline, David I; Weeks, Scarla; Evans, Richard D; Williamson, David H; Hoegh-Guldberg, Ove

    2009-01-01

    Coral reefs around the world are experiencing large-scale degradation, largely due to global climate change, overfishing, diseases and eutrophication. Climate change models suggest increasing frequency and severity of warming-induced coral bleaching events, with consequent increases in coral mortality and algal overgrowth. Critically, the recovery of damaged reefs will depend on the reversibility of seaweed blooms, generally considered to depend on grazing of the seaweed, and replenishment of corals by larvae that successfully recruit to damaged reefs. These processes usually take years to decades to bring a reef back to coral dominance. In 2006, mass bleaching of corals on inshore reefs of the Great Barrier Reef caused high coral mortality. Here we show that this coral mortality was followed by an unprecedented bloom of a single species of unpalatable seaweed (Lobophora variegata), colonizing dead coral skeletons, but that corals on these reefs recovered dramatically, in less than a year. Unexpectedly, this rapid reversal did not involve reestablishment of corals by recruitment of coral larvae, as often assumed, but depended on several ecological mechanisms previously underestimated. These mechanisms of ecological recovery included rapid regeneration rates of remnant coral tissue, very high competitive ability of the corals allowing them to out-compete the seaweed, a natural seasonal decline in the particular species of dominant seaweed, and an effective marine protected area system. Our study provides a key example of the doom and boom of a highly resilient reef, and new insights into the variability and mechanisms of reef resilience under rapid climate change.

  14. Droplets spectrum of air-assisted boom sprayers under different environmental and operational conditions

    Directory of Open Access Journals (Sweden)

    Robson S. Sasaki

    2016-01-01

    Full Text Available ABSTRACT During pesticide spraying, the psychrometric conditions of the air may cause evaporation of the droplets along their trajectory from the nozzle to the target. Thus, this study aimed to evaluate the effect of air psychrometric conditions and operating pressure on the droplet spectrum of air-assisted boom sprayers. The test was performed using a prototype equipped with an axial fan, a flow homogenizer, temperature and relative air humidity sensors, a spray nozzle and a gas-heating system to warm up the airflow. With the assembled system and the aid of a particle analyser, the JSF 11002 spray nozzle was evaluated with respect to droplet spectrum in four air psychrometric conditions (7, 14, 21 and 28 hPa and at four operating pressures (200, 300, 400 and 500 kPa. At the end, evaporation losses were observed during the sprayings. For a given operating pressure and for each increment of 1 hPa in vapor pressure deficit, there was a diameter reduction of approximately 0.0759, 0.518 and 1.514 μm for the parameters DV0.1, DV0.5 and DV0.9, respectively. The diameter of the droplets decreased as the operating pressure increased.

  15. Technical feasibility of a concept radioactive waste disposal facility in Boom clay in the Netherlands

    International Nuclear Information System (INIS)

    Vardon, P.J.; Hicks, M.A.; Fokker, P.A.; Fokkens, J.H.

    2012-01-01

    Document available in extended abstract form only. The current management strategy in the Netherlands for radioactive waste is interim storage for approximately 100 years, followed by final deep geological disposal. At present, both Boom Clay and Salt formations are being considered and investigated via the OPERA (Onderzoeks Programma Eindberging Radioactief Afval) and CORA (Commissie Opberging Radioactief Afval) research programmes respectively, instigated by COVRA (Centrale Organisatie Voor Radioactief Afval). This paper outlines the on-going investigation into the initial technical feasibility of a high-level radioactive waste disposal facility, located within a stratum of Boom Clay, as part of the OPERA research programme. The feasibility study is based on the current Belgian Super-container concept, incorporating specific features relevant to the Netherlands, including the waste inventory and possible future glaciation. The repository is designed to be situated at approximately 500 m depth in a Boom Clay stratum of approximately 100 m thickness, and will co-host vitrified High Level Waste (HLW), spent fuel from research reactors, non-heat generating HLW, Low and Intermediate Level Waste (LILW) and depleted uranium. The total footprint is designed to be 3050 m by 1300 m, and will be segregated by waste type. The waste will be stored in drifts drilled perpendicular to the main galleries and will vary in length and diameter depending upon waste type. The repository life-cycle can be considered in three phases: (i) the pre-operation phase, including the conceptual development, site investigation and selection, design and construction; (ii) the operational phase, including waste emplacement and any period of time prior to closure; and (iii) the post-operational phase. The research on the technical feasibility of the repository will investigate whether the repository can be constructed and whether it is able to perform the appropriate safety functions and meet

  16. Is it ‘boom times’ for baleen whales in the Pacific Arctic region?

    Science.gov (United States)

    2016-01-01

    The marine ecosystem in the Pacific Arctic region has experienced dramatic transformation, most obvious by the loss of sea ice volume (75%), late-summer areal extent (50%) and change in phenology (four to six weeks longer open-water period). This alteration has resulted in an opening of habitat for subarctic species of baleen whales, many of which are recovering in number from severe depletions from commercial whaling in the nineteenth and twentieth centuries. Specifically, humpback, fin and minke whales (Megaptera novaeangliae, Balaenoptera physalus and Balaenoptera acutorostrata) are now regularly reported during summer and autumn in the southern Chukchi Sea. These predators of zooplankton and forage fishes join the seasonally resident grey whale (Eschrichtius robustus) and the arctic-endemic bowhead whale (Balaena mysticetus) in the expanding open-ocean habitat of the Pacific Arctic. Questions arising include: (i) what changes in whale-prey production and delivery mechanisms have accompanied the loss of sea ice, and (ii) how are these five baleen whale species partitioning the expanding ice-free habitat? While there has been no programme of research specifically focused on these questions, an examination of seasonal occurrence, foraging plasticity and (for bowhead whales) body condition suggests that the current state of Pacific Arctic marine ecosystem may be ‘boom times’ for baleen whales. These favourable conditions may be moderated, however, by future shifts in ecosystem structure and/or negative impacts to cetaceans related to increased commercial activities in the region. PMID:27601724

  17. Fast imaging technique to study drop impact dynamics of non-Newtonian fluids.

    Science.gov (United States)

    Xu, Qin; Peters, Ivo; Wilken, Sam; Brown, Eric; Jaeger, Heinrich

    2014-03-05

    In the field of fluid mechanics, many dynamical processes not only occur over a very short time interval but also require high spatial resolution for detailed observation, scenarios that make it challenging to observe with conventional imaging systems. One of these is the drop impact of liquids, which usually happens within one tenth of millisecond. To tackle this challenge, a fast imaging technique is introduced that combines a high-speed camera (capable of up to one million frames per second) with a macro lens with long working distance to bring the spatial resolution of the image down to 10 µm/pixel. The imaging technique enables precise measurement of relevant fluid dynamic quantities, such as the flow field, the spreading distance and the splashing speed, from analysis of the recorded video. To demonstrate the capabilities of this visualization system, the impact dynamics when droplets of non-Newtonian fluids impinge on a flat hard surface are characterized. Two situations are considered: for oxidized liquid metal droplets we focus on the spreading behavior, and for densely packed suspensions we determine the onset of splashing. More generally, the combination of high temporal and spatial imaging resolution introduced here offers advantages for studying fast dynamics across a wide range of microscale phenomena.

  18. Thermo-hydraulic behaviour of Boom Clay using a heating cell. experimental and numerical study

    International Nuclear Information System (INIS)

    Lima, A.; Romero, E.; Vaunat, J.; Gens, A.; Li, X.L.

    2010-01-01

    Document available in extended abstract form only. Boom clay is the subject of extensive research in Belgium dealing with all phenomena that may possibly affect the performance of this geological formation as potential radioactive waste repository. Specifically, thermal loads may play an important role on this low-permeability clay. There are a number of laboratory results concerning the saturated hydro-mechanical behaviour of Boom clay under different temperatures and recent studies on this area are described in Le (2008). Nevertheless, information on clay hydro-mechanical response on heating and cooling paths under small-scale laboratory conditions is less known. To this aim, non-isothermal tests on intact borehole samples were carried out using an axisymmetric heating cell described in Munoz et al. (2009). Heating and cooling paths under nearly constant volume and different target temperatures (maximum 85 deg. C) were performed under controlled hydraulic boundary conditions. The paper presents results of an exhaustive experimental programme performed on a fully-instrumented cell (sample 75 mm in diameter and 100 mm high) with a controlled-power heater installed along the axis of the sample. Different transducers were monitoring the sample response: two miniature pore water pressure transducers located at different heights of the lateral wall of the cell, three thermocouples (two at equivalent locations in relation to the pressure transducers and one near the heater), and top and lateral strain gauges attached to reduced thickness sections of the walls. The cell has top and bottom valves to apply the hydraulic conditions. The protocol of the tests presented three important phases: hydration, heating and cooling. Throughout the heating and cooling phases, the bottom drainage was maintained open at a constant water pressure of 1 MPa using an automatic pressure/volume controller, while the upper valve was kept closed. This back-pressure was important since it

  19. Doom and boom on a resilient reef: climate change, algal overgrowth and coral recovery.

    Directory of Open Access Journals (Sweden)

    Guillermo Diaz-Pulido

    Full Text Available Coral reefs around the world are experiencing large-scale degradation, largely due to global climate change, overfishing, diseases and eutrophication. Climate change models suggest increasing frequency and severity of warming-induced coral bleaching events, with consequent increases in coral mortality and algal overgrowth. Critically, the recovery of damaged reefs will depend on the reversibility of seaweed blooms, generally considered to depend on grazing of the seaweed, and replenishment of corals by larvae that successfully recruit to damaged reefs. These processes usually take years to decades to bring a reef back to coral dominance.In 2006, mass bleaching of corals on inshore reefs of the Great Barrier Reef caused high coral mortality. Here we show that this coral mortality was followed by an unprecedented bloom of a single species of unpalatable seaweed (Lobophora variegata, colonizing dead coral skeletons, but that corals on these reefs recovered dramatically, in less than a year. Unexpectedly, this rapid reversal did not involve reestablishment of corals by recruitment of coral larvae, as often assumed, but depended on several ecological mechanisms previously underestimated.These mechanisms of ecological recovery included rapid regeneration rates of remnant coral tissue, very high competitive ability of the corals allowing them to out-compete the seaweed, a natural seasonal decline in the particular species of dominant seaweed, and an effective marine protected area system. Our study provides a key example of the doom and boom of a highly resilient reef, and new insights into the variability and mechanisms of reef resilience under rapid climate change.

  20. Biomonitoring of the air with Tradescantia pallida (Rose D. R. Hunt var purpurea Boom (Commelinaceae

    Directory of Open Access Journals (Sweden)

    Agnes Barbério

    2012-12-01

    Full Text Available The population growth and the comfort generated by progress have greatly contributed with the increase in the air pollution, making the air in several urban centers polluted by substances that are harmful to human being. This study characterized the air quality in the city of Taubaté, Vale do Paraíba-SP using biomonitoring with Tradescantia pallida (Rose D. R. Hunt purpurea Boom (Commelinaceae. The study was developed in a period of 10 months (September/2010 to June/2011 in five locations (Rodovia Presidente Dutra – heavy vehicle traffic; Estiva – residential area; Parque Aeroporto – industrial area; Campus Bom Conselho – area in the city with heavy vehicle traffic and Agronomy – rural area. Samples were collected on a weekly basis from young inflorescences of exposed plants. After the inflorescences were collected, they were fixed in an absolute ethanol-glacial acetic acid (3:1 solution for 24 h, transferred to ethanol 70% solution and maintained under refrigeration. They were submitted to coloration with acetic carmine and the number of micronucleus was quantified in approximately 300 tetrads for each inflorescence, and slides were prepared with 10 inflorescences/week for each point of study. The average and standard deviations were: Dutra (2.24 ± 1.58, Estiva (2.07 ± 1.33, Parque Aeroporto (1.47 ± 1.05, Bom Conselho (1.42 ± 0.90 and Agronomy (0.82 ± 0.80. Although Taubaté area is a region experiencing urban growth, the data revealed that the air in the city has good quality. Maintaining this balance is very important, requires effort and periodic measurements, and, for this, biomonitoring is a fast, cheap and effective method.

  1. Boom or bubble? Is medical research thriving or about to crash?

    Science.gov (United States)

    Charlton, Bruce G

    2006-01-01

    A recent issue of JAMA (2005; vol. 294) presented a portrait of medical research as a booming enterprise. By contrast I have suggested that medical research is a speculative bubble due to burst. How can two such different predictions be compatible? From inside the expanding world of medical research everything seems fine and getting better. But to people outside the system, it seems like there is an awful lot of money going in, and not much coming out. Professional criteria of success (publications, impact factors, citations, grant income, large teams, etc.) are not the same as the outsider's view of success. Outsiders want the medical research system to generate therapeutic progress as efficiently as possible: the most progress for the least resources. Medical research is not the only good way of spending money and is in competition with other social systems. As funding increases, diminishing returns will set-in, opportunity costs will begin to bite, and there will be more and more social benefit to be gained from spending the extra research money on something else. Therefore, future cuts in medical research will happen because of pressure from outside the system - specifically pressure from other powerful social systems which will press their alternative claims for funding. In the short term, there will be a quantitative decline of research production. But in the longer term the medical research system will re-grow in a more efficient form. After a 'golden age of therapeutic progress in the mid-20th century, recent decades have seen a 'silver age' of scholasticism which is due to end soon. Perhaps a renaissance of medical research lies not too many years in the future.

  2. Il boom dell’Italia in Giappone: riflessioni critiche su Occidentalismo e Italianismo

    Directory of Open Access Journals (Sweden)

    Toshio Miyake

    2011-05-01

    Full Text Available In the modern age, Occidentalism as a process of signifying practices based upon the notion of “the West” has played a hegemonic role in the configuration of collective identity and alterity. The imaginary geography of “the West” has been one of the most effective in inscribing the whole world and humanity along hierarchic and fluid lines of inclusion and exclusion, encompassing global relations of power in geopolitical contexts, as well as knowledge practices in geocultural spheres. In spite of post-colonial engagements aimed to de-naturalize the notions of “the West” and “the East”, little critical attentions has been paid so far to the inter-relational and complicit processes between Occidentalism, Orientalism and self-Orientalism.             This paper shall explore the historical genalogy of discourses on Italy (Italianism in modern Japan, which brought to the Italian boom in the 1990s, elevating at present Italy to the rank of the most-loved foreign country among Japanese women and youth. This study suggests that the prevailing image of Italy has been articulated and re-produced since modern age as an ambivalent icon: a superior-seeming and ‘archetypical West’ based on the insistence of its antique and classical features (Roman Empire, Humanism, Renaissance, and at the same time, an inferior-seeming and ‘backward West’ based on the insistence of its pre-moderns aspects (history, gastronomy, fashion, landscapes, cheerful people, etc.. The popularity of this configuration suggests the strategic relevance of the Italian looking glass self which enables to mediate deep rooted and contradictory pro-western and anti-western tensions in modern and contemporary Japan.

  3. Enhanced somatic embryogenesis in Theobroma cacao using the homologous BABY BOOM transcription factor.

    Science.gov (United States)

    Florez, Sergio L; Erwin, Rachel L; Maximova, Siela N; Guiltinan, Mark J; Curtis, Wayne R

    2015-05-16

    Theobroma cacao, the chocolate tree, is an important economic crop in East Africa, South East Asia, and South and Central America. Propagation of elite varieties has been achieved through somatic embryogenesis (SE) but low efficiencies and genotype dependence still presents a significant limitation for its propagation at commercial scales. Manipulation of transcription factors has been used to enhance the formation of SEs in several other plant species. This work describes the use of the transcription factor Baby Boom (BBM) to promote the transition of somatic cacao cells from the vegetative to embryonic state. An ortholog of the Arabidopsis thaliana BBM gene (AtBBM) was characterized in T. cacao (TcBBM). TcBBM expression was observed throughout embryo development and was expressed at higher levels during SE as compared to zygotic embryogenesis (ZE). TcBBM overexpression in A. thaliana and T. cacao led to phenotypes associated with SE that did not require exogenous hormones. While transient ectopic expression of TcBBM provided only moderate enhancements in embryogenic potential, constitutive overexpression dramatically increased SE proliferation but also appeared to inhibit subsequent development. Our work provides validation that TcBBM is an ortholog to AtBBM and has a specific role in both somatic and zygotic embryogenesis. Furthermore, our studies revealed that TcBBM transcript levels could serve as a biomarker for embryogenesis in cacao tissue. Results from transient expression of TcBBM provide confirmation that transcription factors can be used to enhance SE without compromising plant development and avoiding GMO plant production. This strategy could compliment a hormone-based method of reprogramming somatic cells and lead to more precise manipulation of SE at the regulatory level of transcription factors. The technology would benefit the propagation of elite varieties with low regeneration potential as well as the production of transgenic plants, which

  4. Evidence of wave front folding of sonic booms by a laboratory-scale deterministic experiment of shock waves in a heterogeneous medium.

    Science.gov (United States)

    Ganjehi, Lili; Marchiano, Régis; Coulouvrat, François; Thomas, Jean-Louis

    2008-07-01

    The influence of the planetary boundary layer on the sonic boom received at the ground level is known since the 1960s to be of major importance. Sonic boom propagation in a turbulent medium is characterized by an increase of the mean rise time and a huge variability. An experiment is conducted at a 1:100,000 scale in water to investigate ultrasonic shock wave interaction with a single heterogeneity. The experiment shows a very good scaling with sonic boom, concerning the size of the heterogeneities, the wave amplitude, and the rise time of the incident wave. The wave front folding associated with local focusing, and its link to the increase of the rise time, are evidenced by the experiment. The observed amplification of the peak pressure (by a factor up to 2), and increase of the rise time (by up to about one magnitude order), are in qualitative agreement with sonic boom observations. A nonlinear parabolic model is compared favorably to the experiment on axis, though the paraxial approximation turns out less precise off axis. Simulations are finally used to discriminate between nonlinear and linear propagations, showing nonlinearities affect mostly the higher harmonics that are in the audible range for sonic booms.

  5. The Berkeley Out-of-Order Machine (BOOM): An Industry-Competitive, Synthesizable, Parameterized RISC-V Processor

    Science.gov (United States)

    2015-06-13

    cache coherency system, the privileged ISA support, and the FPGA and ASIC flows – came to BOOM “for free” via the Rocket-chip SoC generator. And as...Rocket-chip SoC generator, allowing us to quickly bring up an entire multi-core processor system (including caches and uncore) by replacing the in-order...in TSMC 45 nm excluding caches (and 1.1 mm2 with 32 kB L1 caches ). The in-order Rocket core has been successfully demonstrated to reach over 1.5 GHz

  6. Human Simulated Intelligent Control with Double-Direction Dead-Zone Compensation for Joint Motion Control of a Large-Sized Boom System

    Directory of Open Access Journals (Sweden)

    Rongsheng Liu

    2015-01-01

    Full Text Available Joint motion control of a 52-meter-long five-boom system driven by proportional hydraulic system is developed. It has been considered difficult due to strong nonlinearities and parametric uncertainties, the effect of which increases with the size of booms. A human simulated intelligent control scheme is developed to improve control performance by modifying control mode and control parameters. In addition, considering the negative effects caused by frequent and redundant reverse actions of the proportional valve, a double-direction compensation scheme is proposed to deal with the dead-zone nonlinearity of proportional valve. Sinusoidal motions are implemented on a real boom system. The results indicate that HSIC controller can improve control accuracy, and dead-zone nonlinearity is effectively compensated by proposed compensation scheme without introducing frequent reverse actions of proportional valve.

  7. Political economy of China and India: dealing with air pollution in the two booming economies

    Directory of Open Access Journals (Sweden)

    Zhiqun Zhu

    2009-11-01

    Full Text Available China e India son dos economías en auge hoy en día, pero ambos sufren de daños al medio ambiente. Para conseguir un desarrollo sostenible, los dos países tienen que prestar más atención a la protección del medio ambiente. Este artículo examina en primer lugar las causas y consecuencias de los problemas de contaminación grave del aire en China e India. A continuación, se describe cómo China y la India tratan el problema de la contaminación del aire y sugiere formas para mejorar. El autor sostiene que el control de la contaminación del aire y de la protección del medio ambiente en general es un proyecto integral que requiere esfuerzos concertados de los gobiernos en todos los niveles, de la comunidad científica, de empresarios, juristas, grupos no gubernamentales y comunitarios, de la comunidad internacional, y de los ciudadanos como individuos. La educación y la estricta aplicación de la ley siguen siendo la clave del éxito. La experiencia de China e India en el control de la contaminación del aire proporcionan algunas lecciones útiles para otros países en desarrollo._____________ABSTRACT:China and India are two booming economies today, but both are suffering from environmental damages. To achieve sustainable develpment, the two countries have to pay more attention to the protection of environment. This article first examines the causes and consequences of the serious air pollution problems in China and India. It then discusses how China and India are dealing with the air pollution problem and suggests ways for improvement. The author argues that air pollution control and environmental protection in general are a comprehensive project that requires concerted efforts by governments at all levels, the scientific communtity, businesses, legal scholars, non-governmental and grass-roots groups, the international community, and individual citizens. Education and stricter law enforcement remain the key to success. China and India

  8. Boom komiksowy. Polski rynek historii obrazkowych w latach 2000-2003

    Directory of Open Access Journals (Sweden)

    Mateusz Zapała

    2011-05-01

    Full Text Available Lata 2000-2003, ze względu na wzmożoną aktywność wydawniczą na polu historii obrazkowych oraz szum medialny jej towarzyszący, bywają określane „boomem komiksowym”. Gwałtowny wzrost koniunktury na komiks w początkach XXI wieku rozpoczęły należące do Egmont Polska: magazyn „Świat Komiksu” oraz imprint Klub Świata Komiksu (publikujący m.in. niebywale popularną serię Thorgal. Wkrótce po komercyjnym sukcesie Egmontu na rynek opowieści obrazkowych wkroczyli inni wydawcy, których można podzielić na dwie grupy. Pierwszą stanowili edytorzy, którzy wcześniej publikowali jedynie książki, np. wydawnictwa Amber, Muza, Siedmioróg. Drugi zbiór tworzyły oficyny stricte komiksowe, m.in. Kultura Gniewu, Mandragora, Post. „Boom komiksowy” doprowadził także do znacznych zmian w strukturze rynku periodycznych historii obrazkowych – prawie wszystkich odbiorców utracił TM-Semic (lider rynku komiksowego w latach 90, wydawca czasopism z przygodami superbohaterów, np. „Batmana”,  nowych czytelników zyskały natomiast niskonakładowe magazyny, które publikowały głównie polski komiks autorski (m.in. „AQQ”, „Krakers”, „KKK”, „Produkt”. W latach 2000-2003 rozwinął się również polski rynek mang (komiksów japońskich, którego liderem w tym czasie było wydawnictwo Japonica Polonica Fantastica (63% udział w rynku. Podczas „boomu komiksowego” rynek  historii obrazkowych skierowanych do dzieci zdominowała oferta Egmontu (np. magazyny „Kaczor Donald” i „Czarodziejki: W.I.T.C.H.” oraz cykl Gigant Poleca. Łącznie w latach 2000-2003 we wszystkich segmentach polskiego rynku komiksowego ukazało się 1455 pozycji komiksowych, czyli prawie o jedną czwartą więcej niż w ciągu całych lat dziewięćdziesiątych.

  9. Developments in modelling of thermohydro-geomechanical behaviour of Boom clay and clay-based buffer materials (Volume 1)

    International Nuclear Information System (INIS)

    Baldi, G.; Hueckel, T.; Peano, A.; Pellegrini, R.

    1991-01-01

    The results of two years of research on thermomechanics of clays performed within CEC contract Fl1W/0150 are described herein. Previous studies (research contracts with CEC/WAS/380.83.7 l) performed by ISMES have evidenced the need for an improved modelling of the volumetric response of natural clays. In a coupled approach, this leads to an improved prediction of pore-pressure development and dissipation. This is crucial for assessing conditions of a possible local thermal failure as verified in laboratory tests done at ISMES. The first part of the study lays the foundations of a comprehensive theoretical treatment of the interaction between water and soil skeleton. It consists in: (a) developing a framework for inclusion of water/soil particle thermally induced interaction into a thermodynamically consistent mixture theory approach (Section 2); (b) studying possible modelling approaches of considering the effective thermal expansion coefficient of pore water dependency on pore water status (Section 2); (c) testing artificial clays to assess pore water thermal expansion dependence on temperature in the presence of different amounts of active clay minerals and also Boom clay (Section 3); (d) performing a laboratory test campaign on Boom clay with special attention to the response in the overconsolidated domain (Section 4). 89 figs., 18 tabs., 102 refs

  10. Prioritizing Wetlands for Waterbirds in a Boom and Bust System: Waterbird Refugia and Breeding in the Murray-Darling Basin.

    Science.gov (United States)

    Bino, Gilad; Kingsford, Richard T; Porter, John

    2015-01-01

    Dryland rivers have considerable flow variability, producing complex ecosystems, processes, and communities of organisms that vary over space and time. They are also among the more vulnerable of the world's ecosystems. A key strategy for conservation of dryland rivers is identifying and maintaining key sites for biodiversity conservation, particularly protecting the quantity and quality of flow and flooding regimes. Extreme variability considerably challenges freshwater conservation planning. We systematically prioritised wetlands for waterbirds (simultaneously for 52 species), across about 13.5% of the Murray-Darling Basin (1,061,469 km2), using a 30-year record of systematic aerial surveys of waterbird populations. Nine key wetlands in this area, primarily lakes, floodplains, and swamps, consistently contributed to a representation target (80%) of total abundances of all 52 waterbird species. The long temporal span of our data included dramatic availability (i.e., booms) and scarcity (i.e., busts) of water, providing a unique opportunity to test prioritisation at extremes of variation. These extremes represented periods when waterbirds were breeding or concentrating on refugia, varying wetland prioritisation. In dry years, important wetlands for waterbirds were riverine and lacustrine (12 wetlands) but this changed in wet years to lacustrine and palustrine (8 wetlands). Such variation in ecosystem condition substantially changes the relative importance of individual wetlands for waterbirds during boom and bust phases. Incorporating this variability is necessary for effective conservation of Murray-Darling Basin waterbirds, with considerable generality for other similarly variable systems around the world.

  11. Steroid-inducible BABY BOOM system for development of fertile Arabidopsis thaliana plants after prolonged tissue culture.

    Science.gov (United States)

    Lutz, Kerry A; Martin, Carla; Khairzada, Sahar; Maliga, Pal

    2015-10-01

    We describe a steroid-inducible BABY BOOM system that improves plant regeneration in Arabidopsis leaf cultures and yields fertile plants. Regeneration of Arabidopsis thaliana plants for extended periods of time in tissue culture may result in sterile plants. We report here a novel approach for A. thaliana regeneration using a regulated system to induce embryogenic cultures from leaf tissue. The system is based on BABY BOOM (BBM), a transcription factor that turns on genes involved in embryogenesis. We transformed the nucleus of A. thaliana plants with BBM:GR, a gene in which the BBM coding region is fused with the glucocorticoid receptor (GR) steroid-binding domain. In the absence of the synthetic steroid dexamethasone (DEX), the BBM:GR fusion protein is localized in the cytoplasm. Only when DEX is included in the culture medium does the BBM transcription factor enter the nucleus and turn on genes involved in embryogenesis. BBM:GR plant lines show prolific shoot regeneration from leaf pieces on media containing DEX. Removal of DEX from the culture media allowed for flowering and seed formation. Therefore, use of BBM:GR leaf tissue for regeneration of plants for extended periods of time in tissue culture will facilitate the recovery of fertile plants.

  12. Layout of the manipulator-arm (boom) for the TFTR fusion reactor (Princeton, USA) under UHV-conditions

    International Nuclear Information System (INIS)

    Klaubert, J.

    1987-01-01

    This presentation shows the main criteria for the layout of the manipulator - arm and the antechamber - vessel of the TFTR - FUSION - REACTOR at Princeton University, PLASMA PHYSICS LABORATORY (USA). The main problem during layout of a manipulator system like the TFTR - Boom has been the limitation of the vertical deflections due to deadweight of the construction. The design problem is rather a deformation problem and a problem of stability than a stress problem. The way of optimizing the ratio between stiffness and deadweight is the most important part during the complete design - process. Additional earthquake requirements need further investigations for a satisfying layout (horizontal forces, weak-axis of moment of inertia). The details of the construction (welding, connections etc.) have to be designed in respect to UHV - requirements --> no holes and no fillet welds (outgasing - rate.) are allowed. All weldings have to be designed as bevel-welds. This manipulator system is designed for working in a plane system (two degrees of freedom). A manipulator system with the same operating capabilities in a three degree of freedom system needs larger cross sections for the different beam-elements than those of the discussed TFTR - BOOM

  13. Population dynamics models based on cumulative density dependent feedback: A link to the logistic growth curve and a test for symmetry using aphid data

    NARCIS (Netherlands)

    Matis, J.H.; Kiffe, T.R.; Werf, van der W.; Costamagna, A.C.; Matis, T.I.; Grant, W.E.

    2009-01-01

    Density dependent feedback, based on cumulative population size, has been advocated to explain and mathematically characterize “boom and bust” population dynamics. Such feedback results in a bell-shaped population trajectory of the population density. Here, we note that this trajectory is

  14. The quinoa boom of the southern Bolivian Altiplano - linking geomorphology, erosion and spatial production patterns

    Science.gov (United States)

    Sander, Lasse; Jacobsen, Sven-Erik

    2014-05-01

    . While agricultural exploitation prior to 2003 was mainly restricted to quaternary alluvial deposit, the post-2003 expansion entered the flat shoreface topography of late Pleistocene Lake Tauca (18-14 ka BP; Placzek et al 2006) and hence a domain of increased soil salinity. These recent developments pretty well illustrate southern Bolivia's "quinoa boom": an escalating, land-intensive production on marginal soils, characterized by high erosion rates and a dissipative resource use. Given the arid conditions and the resulting low resilience of the landscape, the current trends are likely to trigger widespread land degradation, jeopardizing future livelihood opportunities. References Placzek C, Quade J, Patchett, PJ 2006. Geochronology and stratigraphy of late Pleistocene lake cycles on the southern Bolivian Altiplano: Implications for causes of tropical climate change. GSA Bulletin 118, 515-532. Jacobsen, S-E 2011. The situation for quinoa and its production in Southern Bolivia: From economic success to environmental disaster. J. Agronomy & Crop Science 197, 390-399.

  15. Study of the 'Clay of Boom' with regard to the storage of nuclear waste. Appendices; Onderzoek Klei van Boom in verband met eventuele opslag kernafval. Bijlagen

    Energy Technology Data Exchange (ETDEWEB)

    Brugge, J.V.M.; Vrouwe, B.J. [T and A Survey, Amsterdam (Netherlands)

    2011-01-15

    The Dutch government aims to store nuclear waste in the Dutch soil. Geological research organization T and A Survey mapped the areas that match with the demands of the Dutch government regarding underground storage of nuclear waste. These are areas in which the Clay layer of Boom has a minimal thickness of 100 meters and the depth of the top of the clay formation is at least 500 meters. This report contains the appendices with (geological) maps and data. [Dutch] De Nederlandse overheid wil kernafval ondergronds opslaan in de Nederlandse bodem. Geologisch onderzoeksbureau T and A Survey brengt de gebieden in kaart, die voldoen aan de door de overheid gestelde eisen voor mogelijke ondergrondse opslag van kernafval. Het gaat om gebieden waar de Boomse kleilaag een minimale dikte van 100 meter heeft en de diepte van de top van de kleiformatie minimaal 500 meter bedraagt. Dit rapport bevat de bijlagen met (geologische) kaarten en gegevens.

  16. One last boom : Alberta's rapidly expanding oil mines may be the largest and messiest industrial projects in Canadian history

    International Nuclear Information System (INIS)

    Laird, G.

    2001-01-01

    The bitumen deposits of Alberta, 2.5 trillion barrels of oil, of which 300 billion are considered recoverable, represent the greatest single petroleum resources of the world, based on surface and subsurface calculations. Four deposits, covering an area the size of New Brunswick, are located in the area stretching from Cold Lake to Lloydminster (east of Edmonton), the upper reaches of the Athabasca River east to the Peace River. The largest by far is the Athabasca deposit in the vicinity of Fort McMurray, spread over 4.3 million hectares. The deposit is at the centre of the biggest industrial expansion witnessed by the province. Since 1996, 38 billion dollars worth of new projects have been announced. It is estimated that by 2025, the bulk of the national oil production will originate from open-pit mines and underground wells around Fort McMurray. This oil boom has economic benefits for the population, from welders to real estate agents to stakeholders. The environmental effects are not as beneficial. Huge strip mines are being carved next to the Athabasca River, with great amounts of greenhouse gases emissions. The Suncor and Syncrude oil-sands plants combined represent the fourth largest carbon dioxide emission source in Canada. The development of these projects dramatically affects global warming. The nitrogen and sulphur emissions could also acidify lakes and soil in the region. The Suncor mine resulted from the first boom to hit Fort McMurray in 1964. The Syncrude mine is the result of the second boom which took place in 1973. In 1996, Suncor installed a sulphur scrubber system that removes 95 per cent of sulphur dioxide from the electricity and steam-generation plant. Suncor also invested in various projects, such as wind-power, rainforest cultivation and biomass generation. The volume of pollution increases as the operations expand, even if operations are cleaner. If no new gains in pollution control are achieved, it is expected that by 2015, the total

  17. Geo-scientific characterisation of the Boom Clay in the Netherlands in light of permanent confinement of radio-active waste

    NARCIS (Netherlands)

    Griffioen, J.J.; Simmelink, E.; Westerhoff, W.; Koenen, M.; Tambach, T.; Behrends, T.

    2012-01-01

    Recently, the OPERA research program has been initiated in the Netherlands. Its central objective is to develop initial, conditional safety cases for repositories in the Boom Clay and Zechstein rocksalt formations. TNO Geological Survey of the Netherlands has been granted two projects that deal with

  18. The peak of construction. After years of stagnant hospital growth, Colorado sees boom in healthcare construction as enterprising companies pan for gold.

    Science.gov (United States)

    Romano, Michael

    2003-12-15

    As Denver experienced a population boom during the '90s, hospital construction was at a standstill. Now providers are racing to catch up with demand, reflecting a national trend. Four Denver-area facilities, including Sky Ridge Medical Center, left, are open or under construction. "Right now, there's nothing like this going on anywhere," says Dennis Brimhall, of the University of Colorado Hospital.

  19. Fake news of baby booms 9months after major sporting events distorts the public's understanding of early human development science.

    Science.gov (United States)

    Grech, Victor; Masukume, Gwinyai

    2017-12-01

    In France on 27/6/16, Iceland's men's national football team won 2-1, knocking England out of the UEFA European Championship. Nine months after this momentous Icelandic victory, Ásgeir Pétur Þorvaldsson a medical doctor in Iceland, posted a tweet in jest suggesting that a baby boom had occurred as a result of increased celebratory coital activity following the win. The media covered this widely but statistical analysis shows otherwise and this was confirmed by the original tweet source. Given the increase in fake scientific news, it is especially important for scientists to correct misinformation lest the public loses trust in science or gains a distorted understanding of known facts. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. From Boom to Bust: The Effects of Economic Recession on Minority Groups' Experience in the Housing Market

    Directory of Open Access Journals (Sweden)

    From Boom to Bust: The Effects of Economic Recession on Minority Groups' Experience in the Housing Market

    2013-06-01

    Full Text Available The homeownership rate in the US reached an all-time high of 69.2 percent by 2006, attributed to factors like favorable mortgage lending practice, economic boom, and incentive policies. The recent subprime mortgage crisis and economic recession, however, widened the gap in homeownership between racial minorities and whites. A sharp drop in housing price also posed a threat to the amount of equity one could accumulate. In this paper, we examined how the changing economy and both structural and individual-level factors affected the racial disparities in homeownership and home equity, using the 2005 and 2009 American Housing Survey national data. The major finding was that the economic recession affected Blacks the most, followed by Hispanics. Asians, though showing a decline in their home equity, were able to maintain their advantages in the housing market.

  1. A see-saw of pre-Columbian boom regions in southern Peru, determined by large-scale circulation changes

    Science.gov (United States)

    Mächtle, B.; Schittek, K.; Forbriger, M.; Schäbitz, F.; Eitel, B.

    2012-04-01

    Environmental changes and cultural transitions during several periods of Peruvian history show a strong coincidence between humid and dry climatic oscillations and the rise and decline of cultures. It is noteworthy, that alternating periods of geo-ecological fragility and stability occurred in time and space between the coastal Nasca region (14.5° S) and the high Andean northern Titicaca basin, just a few hundred kilometers to the east. Based on a multi-proxy palynological and sedimentological approach to reconstruct palaeoenvironmental changes, we found that the Nasca region received a maximum of precipitation during the archaeological boom times of the Early Horizon and the Early Intermediate Period (800 BC - 650 AD, Paracas and Nasca cultures) as well as during the late intermediate period (1150-1450 AD), whereas, in contrast, the Titicaca region further to the south-east experienced drought and cultural depression during that times. During the Middle Horizon (650 - 1150 AD), the Tiwanaku agronomy and culture boomed in the Titicaca region and expanded to the west, contemporaneous with a raised lake level and more humid conditions. In the Nasca region, runoff for irrigation purposes was reduced and less reliable due to drought. Considering a coincidence between environmental and cultural changes, we state that success and decline of civilizations were controlled by hydrological oscillations, triggering fertility as well as a critical loss of natural resources. In response to spatial changing resources, cultural foci were shifted. Therefore, the success of pre-Columbian civilizations was closely coupled to areas of geo-ecological favorability, which were directly controlled by distinct regional impacts of large-scale circulation mechanisms, including El Niño - Southern Oscillation (ENSO). Changes in the position of the intertropical convergence zone (ITCZ) and the Bolivian anticyclone determined meridional shifts in moisture transport across the Andes, which

  2. Proposed gravity-gradient dynamics experiments in lunar orbit using the RAE-B spacecraft

    Science.gov (United States)

    Blanchard, D. L.; Walden, H.

    1973-01-01

    A series of seven gravity-gradient dynamics experiments is proposed utilizing the Radio Astronomy Explorer (RAE-B) spacecraft in lunar orbit. It is believed that none of the experiments will impair the spacecraft structure or adversely affect the continuation of the scientific mission of the satellite. The first experiment is designed to investigate the spacecraft dynamical behavior in the absence of libration damper action and inertia. It requires stable gravity-gradient capture of the spacecraft in lunar orbit with small amplitude attitude librations as a prerequisite. Four subsequent experiments involve partial retraction, ultimately followed by full redeployment, of one or two of the 230-meter booms forming the lunar-directed Vee-antenna. These boom length change operations will induce moderate amplitude angular librations of the spacecraft.

  3. Dynamics at Solid State Surfaces and Interfaces, Volume 1 Current Developments

    CERN Document Server

    Bovensiepen, Uwe; Wolf, Martin

    2010-01-01

    This two-volume work covers ultrafast structural and electronic dynamics of elementary processes at solid surfaces and interfaces, presenting the current status of photoinduced processes. Providing valuable introductory information for newcomers to this booming field of research, it investigates concepts and experiments, femtosecond and attosecond time-resolved methods, as well as frequency domain techniques. The whole is rounded off by a look at future developments.

  4. The experimental testing of the long-term behaviour of cemented radioactive waste from nuclear research reactors in the geological disposal conditions of the boom clay

    Energy Technology Data Exchange (ETDEWEB)

    Sneyers, A.; Marivoet, J.; Iseghem, P. van [SCK-CEN, B-2400 Mol (Belgium)

    1998-07-01

    Liquid wastes, resulting from the reprocessing of spent nuclear fuel from the BR-2 Materials Testing Reactor, will be conditioned in a cement matrix at the dedicated cementation facility of UKAEA at Dounreay. In Belgium, the Boom clay formation is studied as a potential host rock for the final geological disposal of cemented research reactor waste. In view of evaluating the safety of disposal, laboratory leach experiments and in situ tests have been performed. Leach experiments in synthetic clay water indicate that the leach rates of calcium and silicium are relatively low compared to those of sodium and potassium. In situ experiments on inactive samples are performed in order to obtain information on the microchemical and mineralogical changes of the cemented waste in contact with the Boom clay. Finally, results from a preliminary performance assessment calculation suggest a non-negligible maximum dose rate of 5 10{sup -9} Sv/a for {sup 129}I. (author)

  5. Geochemical characterisation of kerogen from the Boom Clay Formation (Mol, Belgium) and evolution under different thermal stress

    International Nuclear Information System (INIS)

    Deniau, I.

    2002-12-01

    The Boom clay formation in Belgium has been chosen as test site for the disposal of high level radioactive wastes. The organic matter present in the clay (kerogen) is sensible to the thermal stress and can generate a huge number of gaseous and liquid compounds leading to local pH changes and to fracturing processes. In particular, some polar compounds can complex radionuclides. The samples analyzed in this work were taken in the underground laboratory of Mol at a 223 m depth. They have been analyzed in detail using geochemical methods (Rock-Eval pyrolysis, element analysis, transmission and scanning electron microscopy), spectroscopic methods (Fourier transformation infrared spectroscopy, solid state 13 C NMR, Raman) and pyrolytic methods (off-line, on-line and in sealed tubes combined with coupled CG/SM analyses). The study of a representative sample of this formation has permitted to characterize the organic matter at the molecular scale, to determine its fossilization mechanisms and the nature of the organic compounds trapped inside the kerogen. The organic matter of the Boom clays comes mainly from phyto-planktonic matter with an important contribution of terrestrial and bacterial matter. The degradation-recondensation played an important role in its preservation but the presence of numerous oxygenated molecules implies that oxidative incorporation also participated to this preservation. Finally, various products (hydrocarbons, oxygenated and nitrogenous polar compounds) trapped in significant amount inside the macro-molecular structure are released under a relatively weak thermal stress. Moreover several small polar organic molecules are released and can play a significant role in the retention or migration of radionuclides inside the geologic barrier. A sample submitted to a in-situ thermal stress of 80 deg. C during 5 years (Cerberus experiment) do not show any significant change in its kerogen structure with respect to the non-heated reference sample

  6. BUDAYA DALAM LINTASAN SEJARAH: BOOMING NONTON BIOSKOP DI PADANG TEMPO DULU

    Directory of Open Access Journals (Sweden)

    Meri Erawati

    2015-07-01

    Full Text Available This article discusses the existence of cinema as entertainment for the people in Padang during the period 1970s to 2000s. Cinema is a mass entertainment and can be enjoyed by all the community at that time. Cinema became a phenomenal because the movies have become part of people's lifestyles. Cinema furor enlivened by promotions to attract people to come to the cinema through flyers, posters, banners and advertisements in the mass media. The development of technology led to the existence of cinema began to be replaced by the presence of new entertainment media such as television and media screenings of other films such as VCD players so that the film is no longer only be enjoyed in the cinema. Cinema audience popularity and dynamics as well as aspects related to cinema in 1970 this will be discussed within this article.

  7. The effects of elastic supports on the transient vibroacoustic response of a window caused by sonic booms.

    Science.gov (United States)

    Ou, Dayi; Mak, Cheuk Ming

    2011-08-01

    The transient vibration and sound radiation (TVSR) of plate-like structures with general elastic boundary conditions was investigated using the time-domain finite element method (TDFEM) and time-domain boundary element method (TDBEM). In this model, the structure can have arbitrary elastic boundary conditions and hence the effects of the boundary conditions on the TVSR can be effectively studied. The predicted results agreed well with existing experimental data using two classical boundary conditions: simply supported at all edges and clamped-free-free-free. The TVSR of a single panel with a more general boundary condition in two connected chambers was also measured. The predicted results agreed well with these experimental results. The prediction method was subsequently applied to evaluate the effects of elastic boundary supports on the TVSR of a window caused by a sonic boom. Loudness, non-audible acoustic perception, and tactile vibration thresholds were analyzed for different boundary conditions (varying between clamped and simply supported). The possibility of improving the transient vibration and noise isolation performance by selecting an appropriate boundary condition was thereby demonstrated.

  8. Model experiment to study sonic boom propagation through turbulence. Part II. Effect of turbulence intensity and propagation distance through turbulence.

    Science.gov (United States)

    Lipkens, B; Blackstock, D T

    1998-09-01

    A model experiment was reported to be successful in simulating the propagation of sonic booms through a turbulent atmosphere [B. Lipkens and D. T. Blackstock, J. Acoust. Soc. Am. 103, 148-158 (1998)]. In this study the effect on N wave characteristics of turbulence intensity and propagation distance through turbulence are investigated. The main parameters of interest are the rise time and the peak pressure. The effect of turbulence intensity and propagation distance is to flatten the rise time and peak pressure distributions. Rise time and peak pressure distributions always have positive skewness after propagation through turbulence. Average rise time grows with turbulence intensity and propagation distance. The scattering of rise time data is one-sided, i.e., rise times are almost always increased by turbulence. Average peak pressure decreases slowly with turbulence intensity and propagation distance. For the reported data a threefold increase in average rise time is observed and a maximum decrease of about 20% in average peak pressure. Rise times more than ten times that of the no turbulence value are observed. At most, the maximum peak pressure doubles after propagation through turbulence, and the minimum peak pressure values are about one-half the no-turbulence values. Rounded waveforms are always more common than peaked waveforms.

  9. [Changes in tobacco consumption: boom of roll-your-own cigarettes and emergence of e-cigarettes].

    Science.gov (United States)

    Tarrazo, Marina; Pérez-Ríos, Mónica; Santiago-Pérez, María I; Malvar, Alberto; Suanzes, Jorge; Hervada, Xurxo

    To assess changes in smoking prevalence and study roll-your-own (RYO) tobacco and e-cigarette use in the Galician population between 2007 and 2015. Data were obtained from five independent, cross-sectional studies carried out in Galicia (Spain) between 2007-2015 in the population aged 16 and over (n=8,000/year). Prevalence of use was estimated, with 95% confidence intervals, overall, according to sex and by age group, area of residence and level of education. Smoking prevalence decreased from 25.4% in 2007 to 21.8% in 2015. In 2007, 1.8% of current smokers declared that they had smoked RYO tobacco, compared to 18.6% in 2015. Among smokers, RYO tobacco consumption increased across all demographic groups. In both 2014 and 2015, ever use of e-cigarettes was 0.7%. E-cigarette use was more frequent in urban settings. Smoking prevalence decreased in Galicia between 2007 and 2015, and there has been rapid growth in the prevalence of RYO tobacco use. Although smokers are more likely to use e-cigarettes, both former and never smokers declared their use. The boom of RYO cigarettes and the emergence of e-cigarettes highlight the importance of having continuous surveillance systems to identify smoking behavioural changes. Copyright © 2016 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. Influence of chloride ions on the pitting corrosion of candidate HLW overpack materials in synthetic oxidized boom clay water

    International Nuclear Information System (INIS)

    Druyts, F.; Kursten, B.

    1999-01-01

    The corrosion behavior under repository conditions is an important issue in the selection of a container material for the deep-geological disposal of high-level nuclear waste. In considering corrosion resistant materials for the containers, attention has to be focused on localized corrosion. Therefore, cyclic potentiodynamic polarization measurements were used to investigate the pitting behavior of a number of candidate materials, including stainless steels AISI 316L, AISI 316L hMo, AISI 316Ti, higher alloyed stainless steels UNS N08904 and UNS N08926, nickel alloy UNS N96455, and titanium alloy UNS R52400. The environment considered was synthetic oxidized Boom clay water at a temperature of 90 C and with varying chloride content. UNS N96455 and UNS R52400 did not show any pitting corrosion at chloride concentrations up to 10,000 ppm. UNS N08926 was resistant to pitting at 100 and 1,000 ppm Cl - . The other alloys suffered minor or no pitting attack in the reference solution containing 100 ppm chloride, but were attacked at elevated chloride concentrations. A SEM study of the pit morphology on AISI 316L hMo and UHB 904 revealed large central pits surrounded by minor satellite pits, resulting in a rose shape. This morphology probably resulted from subsurface pit growth, where the pit was covered by a thin layer of metal

  11. Opting Out and Leaning In: The Life Course Employment Profiles of Early Baby Boom Women in the United States.

    Science.gov (United States)

    García-Manglano, Javier

    2015-12-01

    Most literature on female employment focuses on the intersection between women's labor supply and family events such as marriage, divorce, or childbearing. Even when using longitudinal data and methods, most studies estimate average net effects over time and assume homogeneity among women. Less is known about diversity in women's cumulative work patterns over the long run. Using group-based trajectory analysis, I model the employment trajectories of early Baby Boom women in the United States from ages 20 to 54. I find that women in this cohort can be classified in four ideal-type groups: those who were consistently detached from the labor force (21 %), those who gradually increased their market attachment (27 %), those who worked intensely in young adulthood but dropped out of the workforce after midlife (13 %), and those who were steadily employed across midlife (40 %). I then explore a variety of traits associated with membership in each of these groups. I find that (1) the timing of family events (marriage, fertility) helps to distinguish between groups with weak or strong attachment to the labor force in early adulthood; (2) external constraints (workplace discrimination, husband's opposition to wife's work, ill health) explain membership in groups that experienced work trajectory reversals; and (3) individual preferences influence labor supply across women's life course. This analysis reveals a high degree of complexity in women's lifetime working patterns, highlighting the need to understand women's labor supply as a fluid process.

  12. Below the radar: the boom of groundwater use in the central part of the Nile Delta in Egypt

    Science.gov (United States)

    El-Agha, Doaa E.; Closas, Alvar; Molle, François

    2017-09-01

    The Nile Delta of Egypt is known for its large irrigated area supplied with water diverted from the Nile River, with a limited use of groundwater, largely for domestic and industrial use. Official statistics for the whole delta indicate that there are a few thousand individual wells used for agriculture by a population of over 2 million farmers. This study, however, shows that a phenomenon of groundwater development for irrigation has been unfolding over the last few years, largely below the radar of managers and researchers. A survey was carried out in the central part of the delta with the objective of (1) uncovering the actual situation of groundwater use in this part of the delta and (2) speculating on its implications. The results of the survey pointed to a recent and booming tube-well drilling industry, with well densities in some parts reaching one well every 2 ha. The development of groundwater abstraction in the central delta is strongly linked to inadequate and/or untimely availability of surface water in the canals. A technical, economic, and management characterization of wells complements the study, showing a continuum between purely private/individual ownership of wells and collective investments and management. Lastly, the article explores the implications of unchecked abstraction at the farm, local and delta scales.

  13. El Boom Petrolero Ecuato-Guineano y sus Implicaciones para el Proceso de Regionalización Centroafricano

    Directory of Open Access Journals (Sweden)

    Sara Nso

    2009-05-01

    Full Text Available A mediados de los años 90, Guinea Ecuatorial, antigua colonia española en el Golfo de Guinea, experimentó un boom petrolero, que le catapultó al estatus de primer productor de crudo de la zona Franco CFA y tercero del Golfo (por detrás de Nigeria y Angola. El caso ecuato-guineano tiene un especial interés para la disciplina de la geopolítica del petróleo, porque se produce en un determinado contexto global, marcado por: (a los atentados del 11 de septiembre, a los que seguirá una inestabilidad creciente en la región de Oriente Medio, que detenta las mayores reservas de petróleo del mundo; y (b la trascendental transformación de los principios clásicos de la cooperación al desarrollo de la Unión Europea, con la firma de las Convenciones de Cotonou. Así pues, si bien el primer factor nos remite a la seguridad del aprovisionamiento de la potencia estadounidense, que se dirige entonces a la joven y fulgurante región del Golfo de Guinea, en África Central, el segundo acabará ofreciendo la clave de la ofensiva ecuato-guineana para hacerse con el liderazgo de la región centroafricana.

  14. At the heart of the industrial boom: Australian snubfin dolphins in the Capricorn Coast, Queensland, need urgent conservation action.

    Science.gov (United States)

    Cagnazzi, Daniele; Parra, Guido J; Westley, Shane; Harrison, Peter L

    2013-01-01

    The recent industrial boom along the Australian coastline has increased concerns about the long term conservation of snubfin dolphins along the Queensland coast. National assessment of the conservation status and management of the Australian snubfin dolphin is currently hindered by the lack of adequate biological and ecological information throughout most of its range. In response to the issue of determining the conservation status of species with broad ranges, the IUCN has provided a framework for assessing the threatened status of regional populations. In this study we assessed the conservation status of a small geographically isolated population of snubfin dolphins living in the Fitzroy River region, Queensland, Australia, against the IUCN criteria for regional populations. A review of all available sightings data and stranding information indicates that this is the southernmost resident population of snubfin dolphins in Australian waters. The Fitzroy River snubfin dolphin population is composed of less than 100 individuals, with a representative range and core area of less than 400 and 300 km(2) respectively. The area most often used by snubfin dolphins within the representative range and core area was estimated to be about 292 and 191 km(2), respectively. A decrease in representative range, core area and preferred habitat between 14 and 25% is projected to occur if a planned industrial port development were to occur. These results are robust to uncertainty and considering the low level of formal protection and future threats, a classification of this subpopulation under the IUCN Red List as "Endangered" is appropriate.

  15. The detection and prevention of unintentional consumption of DOx and 25x-NBOMe at Portugal's Boom Festival.

    Science.gov (United States)

    Martins, Daniel; Barratt, Monica J; Pires, Cristiana Vale; Carvalho, Helena; Vilamala, Mireia Ventura; Espinosa, Iván Fornís; Valente, Helena

    2017-05-01

    This paper describes the misrepresentation of LSD at Portugal's Boom Festival 2014 and the prevention of unintentional consumption of DOx and 25x-NBOMe among LSD consumers attending a drug-checking service. Two hundred forty-five drug samples expected to contain LSD were submitted to the drug-checking service for chemical analysis. One hundred ten post-test questionnaires were successfully matched with test results. About 67.3% of the alleged LSD samples tested contained only LSD; 0.8% contained LSD combined with adulterants; 24.1% did not contain LSD but did contain another psychoactive substance, including 11.4% that were 2,5-dimethoxyamphetamine derivatives and 9.8% that were N-benzyl-2,5-dimethoxyphenethylamine derivatives; and no psychoactive substance was detected in 7.8%. The majority of service users who received unexpected test results regarding their alleged LSD (74.2%) reported that they did not intend to consume the drug. Following dissemination of alerts on day 2, a larger than expected proportion of all tests conducted were for LSD, when comparing the 2014 festival to 2012, where no such alert was disseminated. Although these results support the provision of integrated drug-checking services in party settings, evidence of their utility and effectiveness would be improved through future research incorporating more robust measures of outcomes following provision of drug-checking results. Copyright © 2017 John Wiley & Sons, Ltd.

  16. The role of natural organic matter in the migration behaviour of americium in the Boom clay - Part II: analysis of migration experiments

    International Nuclear Information System (INIS)

    Hicks, T.; Bennett, D.; Maes, N.; Wang, L.; Warwick, P.; Hall, T.; Walker, G.; Dierckx, A.

    2005-01-01

    Full text of publication follows: In demonstrating the suitability of Boom Clay as a potential site for the disposal of radioactive waste in Belgium, the role of the relatively high amount of Natural Organic Matter (NOM) present in the Boom Clay on the mobility of critical radionuclides needs investigation. Trivalent actinides and lanthanides form strong complexes with humic substances. Complexation of these trivalent radionuclides with NOM present in the Boom Clay may have opposing effects. If complexed by the aqueous phase (mobile) NOM, radionuclide transport will be governed by the mobility of these dissolved radionuclide-NOM species. If complexed by the solid phase (immobile) NOM, migration will be retarded. One of the aims of the EC projects TRANCOM-Clay and TRANCOM-II was to investigate the role of mobile NOM as radionuclide carrier with the objective of deriving conceptual models that can be implemented in repository performance assessment (PA) models. A separate paper describes the results of column migration experiments involving the transport of 241 Am- 14 C-NOM complexes through Boom Clay cores. This paper describes the transport model, POPCORN, that was developed to describe and evaluate the influence of NOM on radionuclide transport in clay, taking into account attachment/detachment rates of NOM to clay surfaces and the kinetics of RN complexation to, and destabilization from, NOM. The POPCORN model was used to evaluate diffusion experiments involving injection of 14 C-labelled NOM in Boom Clay cores. Model fits were obtained by varying the rates of filtration of NOM by attachment to the surface of the clay matrix. POPCORN was then used to analyse the 241 Am- 14 C-NOM migration experiments. The stability properties of the 241 Am-NOM were characterised by kinetic constants, and good matches to the migration data were achieved for the experiments. The findings suggest that a small sub-population of the original 241 Am-OM is the most stable, and that this

  17. On the role of anisotropy in the perturbation of Boom Clay by a deep disposal repository for high-level wastes

    International Nuclear Information System (INIS)

    Sillen, X.; Li, X.L.; Van Marcke, P.; Chen, G.; Bastiaens, W.

    2010-01-01

    Document available in extended abstract form only. All along the characterisation programme of the Boom Clay, a potential host rock for geological disposal of long-lived, heat-emitting radioactive waste, evidences of anisotropy of key thermo-hydro-mechanical (THM) properties have been collected through direct observations and laboratory measurements. In parallel, evidences of anisotropic THM behaviour of the clay massif were obtained during excavations and in-situ experiments in the underground research laboratory HADES at Mol. Careful analysis of the observations and simple modelling reveal the key role of the anisotropy of the material properties and, to a lesser extent, the in situ stresses in the development of a damaged zone around the galleries and the hydro-mechanical perturbation in the clay massif. As a consequence of the sedimentary deposition process, clay formations often exhibit visible bedding. This is the case for Boom Clay. Like other deep clays, Boom Clay also exhibits pronounced strain anisotropy under certain hydro-mechanical loading. Isotropic compression tests performed in the early nineties have shown that, for Boom Clay at a depth of about 225 m, the increments of deformation perpendicular to the bedding planes, i.e. vertical, are about two times larger than increments of deformation parallel to the bedding planes, i.e. horizontal. Moreover, it was observed that this mechanical anisotropy decreases progressively as the isotropic stress is increased. Drained heating tests under constant isotropic loading also evidenced anisotropic behaviour during thermo-consolidation. Like the mechanical properties, hydraulic and thermal properties of the Boom Clay also show anisotropy: lab and in situ measurements suggest that the horizontal hydraulic conductivity is about twice the vertical one while the ratio between horizontal and vertical thermal conductivities is about 1.4. The anisotropic THM behaviour of the Boom Clay was evidenced during excavations

  18. Water Treatment Systems Make a Big Splash

    Science.gov (United States)

    2004-01-01

    In the 1960s, NASA's Manned Space Center (now known as Johnson Space Center) and the Garrett Corporation, Air Research Division, conducted a research program to develop a small, lightweight water purifier for the Apollo spacecraft that would require minimal power and would not need to be monitored around-the-clock by astronauts in orbit. The 9-ounce purifier, slightly larger than a cigarette pack and completely chlorine-free, dispensed silver ions into the spacecraft s water supply to successfully kill off bacteria. A NASA Technical Brief released around the time of the research reported that the silver ions did not impart an unpleasant taste to the water. NASA s ingenuity to control microbial contamination in space caught on quickly, opening the doors for safer methods of controlling water pollutants on Earth.

  19. Impact splash chondrule formation during planetesimal recycling

    OpenAIRE

    Lichtenberg, Tim; Golabek, Gregor J.; Dullemond, Cornelis P.; Schönbächler, Maria; Gerya, Taras V.; Meyer, Michael R.

    2017-01-01

    Chondrules are the dominant bulk silicate constituent of chondritic meteorites and originate from highly energetic, local processes during the first million years after the birth of the Sun. So far, an astrophysically consistent chondrule formation scenario, explaining major chemical, isotopic and textural features, remains elusive. Here, we examine the prospect of forming chondrules from planetesimal collisions. We show that intensely melted bodies with interior magma oceans became rapidly c...

  20. Ultra-wideband pose detection system for boom-type roadheader based on Caffery transform and Taylor series expansion

    Science.gov (United States)

    Fu, Shichen; Li, Yiming; Zhang, Minjun; Zong, Kai; Cheng, Long; Wu, Miao

    2018-01-01

    To realize unmanned pose detection of a coalmine boom-type roadheader, an ultra-wideband (UWB) pose detection system (UPDS) for a roadheader is designed, which consists of four UWB positioning base stations and three roadheader positioning nodes. The positioning base stations are used in turn to locate the positioning nodes of the roadheader fuselage. Using 12 sets of distance measurement information, a time-of-arrival (TOA) positioning model is established to calculate the 3D coordinates of three positioning nodes of the roadheader fuselage, and the three attitude angles (heading, pitch, and roll angles) of the roadheader fuselage are solved. A range accuracy experiment of a UWB P440 module was carried out in a narrow and closed tunnel, and the experiment data show that the mean error and standard deviation of the module can reach below 2 cm. Based on the TOA positioning model of the UPDS, we propose a fusion-positioning algorithm based on a Caffery transform and Taylor series expansion (CTFPA). We derived the complete calculation process, designed a flowchart, and carried out a simulation of CTFPA in MATLAB, comparing 1000 simulated positioning nodes of CTFPA and the Caffery positioning algorithm (CPA) for a 95 m long tunnel. The positioning error field of the tunnel was established, and the influence of the spatial variation on the positioning accuracy of CPA and CTFPA was analysed. The simulation results show that, compared with CPA, the positioning accuracy of CTFPA is clearly improved, and the accuracy of each axis can reach more than 5 mm. The accuracy of the X-axis is higher than that of the Y- and Z-axes. In section X-Y of the tunnel, the root mean square error (RMSE) contours of CTFPA are clear and orderly, and with an increase in the measuring distance, RMSE increases linearly. In section X-Z, the RMSE contours are concentric circles, and the variation ratio is nonlinear.

  1. Time trends of polybrominated diphenyl ethers in East China Seas: Response to the booming of PBDE pollution industry in China.

    Science.gov (United States)

    Li, Yuanyuan; Lin, Tian; Hu, Limin; Feng, Jialiang; Guo, Zhigang

    2016-01-01

    The East China Seas (ECSs) are the receptors of the land-based persistent organic pollutants (POPs), such as polybrominated diphenyl ethers (PBDEs) mainly from China through atmospheric deposition driven by the East Asian winter monsoon and fluvial discharge (e.g., Yangtze River and Yellow River), making the offshore sediments to be a good proxy to reconstruct history of those pollutants in China. In this work, four well-placed sediment cores were extracted from the mud areas in the ECSs, and the (210)Pb-dated cores were analyzed to yield historical concentration profiles of PBDEs in the area. The results showed that there was a persistent increase from 1970s and almost no clear sign in the decline of PBDEs until recently in China. More importantly, there was a faster increase of PBDEs from 1990s in China; while this period was just shown as gradually leveling off or even declining trends in developed countries. The persistently increasing trend of PBDEs in China since 1990s could be largely due to the booming of the manufacturing industry and unexpectedly transfer of PBDE pollution from developed countries to China. Besides, the relative high concentrations and fluxes of PBDEs in the core from coastal ECS located near a well-known electrical/electronic waste (e-waste) recycling area suggests an important contribution of PBDE emissions from recycling centers of e-waste in China. Although efforts in environmental monitoring of PBDE contamination have been substantially increased over the last decade, China is still lagging behind in terms of nationwide regulation of PBDE usage and treatment of disposal PBDE-containing products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Validation of the transport parameters of silica at 30°C in Boom Clay by a combined glass dissolution/diffusion experiment

    International Nuclear Information System (INIS)

    Aertsens, M.; Lemmens, K.

    2010-01-01

    Document available in extended abstract form only. In Belgium the disposal of vitrified radioactive waste in Boom Clay is considered. The Boom Clay beneath the Mol-Dessel nuclear zone is a reference methodological site for supporting R and D. Safety studies require to estimate the release rate of hazardous radionuclides from the host glass and their transport rate in Boom Clay. The radionuclides are released as a result of the glass matrix dissolution. In the present Belgian reference 'supercontainer' disposal design, the waste glass is surrounded by a concrete buffer, but in the previous disposal design, a bentonite backfill was foreseen. The close interaction between the dissolving glass and clayey materials was studied using Boom Clay as a reference clay. Dissolution of glass next to clay is described by a model initially developed by Pescatore, according to which at large times the glass dissolution rate is controlled by the transport parameters of dissolved silica in Boom Clay: the apparent diffusion coefficient D and the product?R of the diffusion accessible porosity? and the retardation factor R. The values of these parameters have been measured by diffusion experiments. These values and the Pescatore model are validated by experiments where 32 Si doped glass dissolves next to clay. These experiments allow to determine not only the glass mass loss as a function of time, but also the 32 Si profile in the clay and the pore water composition close to the glass. The combination of these measurements makes it possible to determine all parameters of the Pescatore model. Because at 90 deg. C silica precipitates have been observed next to a dissolving glass by Pozo, the Pescatore model is extended with a precipitation term. Another extension takes into account the finite size of the clay cores. Three combined glass dissolution/diffusion tests with durations up to 1600 days were performed with SON68 glass in compact Boom Clay at 30 deg. C. These tests were

  3. Synthesis of Fe–Ni bimetallic nanoparticles from pixel target ablation: plume dynamics and surface characterization

    International Nuclear Information System (INIS)

    Niu Xiaoxu; Murray, Paul T.; Sarangan, Andrew

    2012-01-01

    A novel Fe–Ni bimetallic nanoparticle synthesis technique, denoted pixel target ablation, is reported. The technique entails ablating a thin film target consisting of patterned Fe and Ni pixels with a selected ratio using a KrF excimer laser. The laser energy breaks a known amount of target materials into metal atoms, which then form nanoparticles by recombination in the gas phase. Due to the nature of thin-film ablation, splashing of large particles was eliminated with the added benefit of minimizing nanoparticle agglomeration. Plume dynamics and surface characterizations were carried out to exploit the formation of Fe–Ni nanoparticles more fully. The composition was readily controlled by varying the initial relative amount of Fe and Ni target pixels. Synthesis of multi-element nanoparticles by pixel target ablation should be possible with any element combination that can be prepared as a thin-film target.

  4. Do high levels of unemployment influence the health of those who are not unemployed? A gendered comparison of young men and women during boom and recession.

    Science.gov (United States)

    Novo, M; Hammarström, A; Janlert, U

    2001-08-01

    Research has shown that health among young people, particularly women, deteriorates during a recession compared to a boom. It seems that the trade cycle mainly affects the health of those who are not long-term unemployed. The aim of this study was to analyse the relation between the health of non-unemployed people and the levels of unemployment in society. Two groups of young people aged 21 were surveyed, one in 1986 (the boom group, n = 1083) and one in 1994 (the recession group, n = 898). The non-response rate was 2% in the first and 10% in the second group. Both groups were investigated with a self-administered questionnaire, which included questions about somatic and psychological health, as well as experiences of employment, unemployment, education and labour market programmes. Young men and women generally reported more somatic and psychological symptoms during recession than boom. The only exception was psychological symptoms among men, which was of the same magnitude during both periods. Poorer health during recession was found among women in work and in labour market programmes, as well as among both male and female students. Multiple regression analysis was performed in order to analyse if the occupational-related health effects of the trade cycle remained after controlling for possible moderating factors. The effects of unemployment in society on young people's health may be mediated through pessimism about the future, high demands and financial problems. Lack of control over the work situation may also be an important contributing factor to ill health among women during recession. The trade cycle was correlated with ill health among women only. Possible explanations for poorer health among women during a recession were discussed.

  5. Ultimate Cavity Dynamics of Hydrophobic Spheres Impacting on Free Water Surfaces

    KAUST Repository

    Mansoor, Mohammad M.

    2012-12-01

    Cavity formation resulting from the water-entry of solid objects has been the subject of extensive research owing to its practical relevance in naval, military, industrial, sports and biological applications. The cavity formed by an impacting hydrophobic sphere normally seals at two places, one below (deep seal) and the other above the water surface (surface seal). For Froude numbers , the air flow into the resulting cavity is strong enough to suck the splash crown above the surface and disrupt the cavity dynamics before it deep seals. In this research work we eliminate surface seals by means of a novel practice of using cone splash-guards and examine the undisturbed transient cavity dynamics by impact of hydrophobic spheres for Froude numbers ranging . This enabled the measurement of extremely accurate pinch-off heights, pinch-off times, radial cavity collapse rates, and jet speeds in an extended range of Froude numbers compared to the previous work of Duclaux et al. (2007). Results in the extended regime were in remarkable agreement with the theoretical prediction of scaled pinch-off depth, and experimentally derived pinch-off time for . Furthermore, we investigated the influence of confinement on cavity formation by varying the cross-sectional area of the tank of liquid. In conjunction with surface seal elimination we observed the formation of multiple pinch-off points where a maximum of four deep seals were obtained in a sequential order for the Froude number range investigated. The presence of an elongated cavity beneath the first pinch-off point 5 resulted in evident "kinks" primarily related to the greatly diminished air pressure at the necking region caused by supersonic air flows (Gekle et al. 2010). Such flows passing through second pinch-offs were also found to choke the cavities beneath the first pinch- off depths causing radial expansion and hence disappearance of downward jets.

  6. Model Deformation Measurements of Sonic Boom Models in the NASA Ames 9- by 7-Ft Supersonic Wind Tunnel

    Science.gov (United States)

    Schairer, Edward T.; Kushner, Laura K.; Garbeff, Theodore J.; Heineck, James T.

    2015-01-01

    The deformations of two sonic-boom models were measured by stereo photogrammetry during tests in the 9- by 7-Ft Supersonic Wind Tunnel at NASA Ames Research Center. The models were geometrically similar but one was 2.75 times as large as the other. Deformation measurements were made by simultaneously imaging the upper surfaces of the models from two directions by calibrated cameras that were mounted behind windows of the test section. Bending and twist were measured at discrete points using conventional circular targets that had been marked along the leading and trailing edges of the wings and tails. In addition, continuous distributions of bending and twist were measured from ink speckles that had been applied to the upper surfaces of the model. Measurements were made at wind-on (M = 1.6) and wind-off conditions over a range of angles of attack between 2.5 deg. and 5.0 deg. At each condition, model deformation was determined by comparing the wind-off and wind-on coordinates of each measurement point after transforming the coordinates to reference coordinates tied to the model. The necessary transformations were determined by measuring the positions of a set of targets on the rigid center-body of the models whose model-axes coordinates were known. Smoothly varying bending and twist measurements were obtained at all conditions. Bending displacements increased in proportion to the square of the distance to the centerline. Maximum deflection of the wingtip of the larger model was about 5 mm (2% of the semispan) and that of the smaller model was 0.9 mm (1% of the semispan). The change in wing twist due to bending increased in direct proportion to distance from the centerline and reached a (absolute) maximum of about -1? at the highest angle of attack for both models. The measurements easily resolved bending displacements as small as 0.05 mm and bending-induced changes in twist as small as 0.05 deg.

  7. The Tangdan Copper Mines and the 1733 Earthquake: A Mining Community before the Boom in the Far Southwest of Qing China

    Directory of Open Access Journals (Sweden)

    Nanny Kim

    2014-12-01

    Full Text Available In the official records, copper mines in the southwest of the Qing empire seem to suddenly appear in the late 1730s. In part, this impression is an effect of government attention. Copper, which was the most important metal for casting cash coins, became a pressing concern when imports of Japanese copper dwindled. The government responded by developing domestic resources. Seemingly overnight, Yunnan mines reached impressive levels of productivity and replaced imports. For several decades, the Tangdan mines in northeastern Yunnan supplied most of the copper consumed by the centrally important metropolitan mints. The sudden boom is remarkable and not entirely plausible. This article reassesses the history of Qing-period mining by examining a particular case study. It explores an essay about the Dongchuan earthquake of 1733 that provides a glimpse at the empire’s leading copper mines on the eve of the recorded boom. A close analysis of figures, mining technology, and organizational structures reveals that the mines had been developed by mining entrepreneurs and migrant workers for a considerable period of time outside government attention, operating in a gray zone of unlicensed exploitation. The studied case permits a new assessment of the role of the state and of nonstate players in the industry. Moreover, it throws a new light on the image of Qing society and economy created by the official emphasis on agriculture and the actual role of the nonagrarian sector.

  8. Measured Sonic Boom Signatures Above and Below the XB-70 Airplane Flying at Mach 1.5 and 37,000 Feet

    Science.gov (United States)

    Maglieri, Domenic J.; Henderson, Herbert R.; Tinetti, Ana F.

    2011-01-01

    During the 1966-67 Edwards Air Force Base (EAFB) National Sonic Boom Evaluation Program, a series of in-flight flow-field measurements were made above and below the USAF XB-70 using an instrumented NASA F-104 aircraft with a specially designed nose probe. These were accomplished in the three XB-70 flights at about Mach 1.5 at about 37,000 ft. and gross weights of about 350,000 lbs. Six supersonic passes with the F-104 probe aircraft were made through the XB-70 shock flow-field; one above and five below the XB-70. Separation distances ranged from about 3000 ft. above and 7000 ft. to the side of the XB-70 and about 2000 ft. and 5000 ft. below the XB-70. Complex near-field "sawtooth-type" signatures were observed in all cases. At ground level, the XB-70 shock waves had not coalesced into the two-shock classical sonic boom N-wave signature, but contained three shocks. Included in this report is a description of the generating and probe airplanes, the in-flight and ground pressure measuring instrumentation, the flight test procedure and aircraft positioning, surface and upper air weather observations, and the six in-flight pressure signatures from the three flights.

  9. ¿Hipertrofia inmobiliaria? Análisis de las pautas territoriales del boom e implicaciones del estallido de la burbuja en Cataluña

    Directory of Open Access Journals (Sweden)

    Aaron Gutiérrez

    2015-01-01

    Full Text Available El trabajo desarrolla un análisis de las implicaciones territoriales de la producción de vivienda en Cataluña durante los años del boom inmobiliario. Se analiza la desigual distribución espacial de los impactos derivados del elevado volumen de producción combinados con la actual crisis inmobiliaria, así como las lógicas espaciales que subyacen en estos procesos. La proliferación de viviendas inacabadas y vacías presenta una distribución territorial que permite identificar terri-torios afectados por la sobreproducción y/o con una mayor concentración de expectativas de negocio inmobiliario frustrado.El estudio de los impactos territoriales de la crisis inmobiliaria actual no puede analizarse de for-ma separada a la huella generada por la hipertrofia inmobiliaria precedente. Por ello, las pautas territoriales de efectos derivados de ésta (viviendas vacías e inacabadas se situarán en relación a las lógicas espaciales de la producción de vivienda durante el boom, a sus vínculos con un mo-delo de urbanizador expansivo y, en definitiva, a una geografía de la producción de vivienda en Cataluña.

  10. Boom. Bust. Build.

    Science.gov (United States)

    Kite, Vance; Park, Soonhye

    2018-01-01

    In 2006 Jeanette Wing, a professor of computer science at Carnegie Mellon University, proposed computational thinking (CT) as a literacy just as important as reading, writing, and mathematics. Wing defined CT as a set of skills and strategies computer scientists use to solve complex, computational problems (Wing 2006). The computer science and…

  11. UKAEA: boom or bust

    International Nuclear Information System (INIS)

    Surrey, J.

    1979-01-01

    The future of the UKAEA is considered in the light of present government policies concerning nuclear power generation. Energy forecasts are drastically lower and the uncertainty surrounding the future of the industry has led to the loss of key staff. It is felt that it is urgent to identify the resources and skills that are specific to nuclear design and engineering and to examine how they can best be organised and retained and that this problem must have precedence over the fast reactor question. The assurance of a future role which is nationally and personally worthwhile will remove much of the uncertainty for the scientists and will make it less likely that a breeder is built for the wrong reason. (UK)

  12. The microprocessor boom

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    The applications of microprocessors in high energy physics experiments are discussed. Many benefits are predicted for data acquisition and handling systems and for control and monitoring functions. (W.D.L.).

  13. The Obama Books Boom

    Science.gov (United States)

    Roach, Ronald

    2009-01-01

    As Barack Obama's rise to power inspires a flood of books, scholars hope the publishing trend will yield serious analysis. Barack Obama's rise from Illinois politics to the U.S. presidency has inspired authors to produce a flood of books chronicling the 44th commander in chief's life story and political career. Obama's political odyssey invites…

  14. Booms, Busts, and Divorce

    Science.gov (United States)

    Hellerstein, Judith K.; Morrill, Melinda Sandler

    2013-01-01

    For almost a century, anecdotes have suggested that divorce rates decline during recessions. However, until very recently there has been surprisingly little formal empirical evidence on whether such a link exists, let alone its magnitude if it does. Moreover, the anticipated direction of the effect is ambiguous theoretically. Although previous studies have concluded that individual job loss destabilizes marriages, macroeconomic conditions may affect divorce probabilities even for those not directly experiencing a job shock. We add to the few existing contemporaneous studies of the effects of macroeconomic shocks on divorce by conducting an empirical analysis of the relationship between state-level unemployment rates and state-level divorce rates using vital statistics data on divorces in the United States from 1976–2009. We find a significant and robust negative relationship between the unemployment and divorce rates, whereby a one percentage point rise in the unemployment rate is associated with a decrease of 0.043 divorces per one thousand people, or about a one percent fall in the divorce rate. The result that divorce is pro-cyclical is robust to a host of alternative empirical specifications, to disaggregating by state characteristics and time period, to expanding the unemployment series back to 1970, and to using alternative measures of local economic conditions. PMID:25221634

  15. Boom Booom Net Radio

    DEFF Research Database (Denmark)

    Grimshaw, Mark Nicholas; Yong, Louisa; Dobie, Ian

    1999-01-01

    Internet radio is one of the growth areas of the Internet but, as this article will show, is fraught with difficulties and frustration for both the modestly-funded broadcaster (bitcaster) and the listener. The article will illustrate some of these problems by means of a short case study of an exi...

  16. Solar dynamic power systems for space station

    Science.gov (United States)

    Irvine, Thomas B.; Nall, Marsha M.; Seidel, Robert C.

    1986-01-01

    The Parabolic Offset Linearly Actuated Reflector (POLAR) solar dynamic module was selected as the baseline design for a solar dynamic power system aboard the space station. The POLAR concept was chosen over other candidate designs after extensive trade studies. The primary advantages of the POLAR concept are the low mass moment of inertia of the module about the transverse boom and the compactness of the stowed module which enables packaging of two complete modules in the Shuttle orbiter payload bay. The fine pointing control system required for the solar dynamic module has been studied and initial results indicate that if disturbances from the station are allowed to back drive the rotary alpha joint, pointing errors caused by transient loads on the space station can be minimized. This would allow pointing controls to operate in bandwidths near system structural frequencies. The incorporation of the fine pointing control system into the solar dynamic module is fairly straightforward for the three strut concentrator support structure. However, results of structural analyses indicate that this three strut support is not optimum. Incorporation of a vernier pointing system into the proposed six strut support structure is being studied.

  17. A Whitham-Theory Sonic-Boom Analysis of the TU-144 Aircraft at a Mach Number of 2.2

    Science.gov (United States)

    Mack, Robert J.

    1999-01-01

    Officially, the Tu-144 was the first supersonic-cruise, passenger-carrying aircraft to enter commercial service. Design, construction, and testing were carried out by the Soviet Union, flight certification was by the Soviet Union, and the only regular passenger flights were scheduled and flown across the territory of the Soviet Union. Although it was not introduced to international passenger service, there were many significant engineering accomplishments achieved in the design, production, and flight of this aircraft. Development of the aircraft began with a prototype stage. Systematic testing and redesign led to a production aircraft in discrete stages that measurably improved the performance of the aircraft from the starting concept to final aircraft certification. It flew in competition with the English-French Concorde for a short time, but was withdrawn from national commercial service due to a lack of interest by airlines outside the Soviet Union. NASA became interested in the Tu- 144 aircraft when it was offered for use as a flying "testbed" in the study of operating characteristics of a supersonic-cruise commercial airplane. Since it had been in supersonic-cruise service, the Tu- 144 had operational characteris'tics similar to those anticipated in the conceptual aircraft designs being studied by the United States aircraft companies. In addition to the other operational tests being conducted on the Tu-144 aircraft, it was proposed that two sets of sonic-boom pressure signature measurements be made. The first set would be made on the ground, using techniques and devices similar to those in reference I and many other subsequent studies. A second set would be made in the air with an instrumented aircraft flying close under the Tu-144 in supersonic flight. Such in-flight measurements would require pressure gages that were capable of accurately recording the flow-field overpressures generated by the Tu- 144 at relatively close distances under the vehicle

  18. Comparação entre dois tipos de suspensão passiva de barra em condições simuladas de pista de prova normalizada Comparison between two types of passive boom suspension under simulated conditions of track test

    Directory of Open Access Journals (Sweden)

    Cristiano O. Pontelli

    2010-08-01

    Full Text Available Neste trabalho, foram feitas algumas análises sobre o comportamento dinâmico simulado de dois tipos de suspensões passivas das barras dos pulverizadores tracionados. Estas análises foram conduzidas em condições virtuais de pista de prova normalizada ISO 5008, com dois níveis de velocidade de deslocamento do pulverizador (5 km h-1 e 15 km h-1 e em dois perfis de pista existentes na norma (acidentada e suavizada. Foram utilizados nas simulações os softwares MATLAB®; SIMULINK® e Visual Nastran®. Os resultados mostram que a suspensão do tipo trapezoidal teve melhor desempenho em baixas frequências de excitação (w In this paper we conducted several analysis of the simulated dynamic behavior of two passive suspension types of the trailed sprayer booms. The suspension analysis was conducted under conditions of a bump track test ISO 5008, with two levels of speed (5 km h-1 and 15 km h-1 and two track profiles proposed in these standards (bumpy and smooth. It was used the simulations software MATLAB®; SIMULINK® and Visual Nastran ®. The results obtained showed that suspensions of trapezoidal type have good performance at low frequencies input (w < 0,2 Hz while suspensions of simple pendulum type have good performance in others conditions.

  19. Children of boom and recession and the scars to the mental health--a comparative study on the long term effects of youth unemployment.

    Science.gov (United States)

    Virtanen, Pekka; Hammarström, Anne; Janlert, Urban

    2016-01-20

    Earlier research shows that there is an association between unemployment and poor mental health, and that recovery from the damages to mental health obtained during unemployment remains incomplete over a long period of time. The present study relates this 'mental health scarring' to the trade cycle, exploring if those exposed to youth unemployment during boom differ from those exposed during recession with respect to mental health in the middle age. The sample consists of two cohorts from the same industrial town in Northern Sweden: the cohort born in 1965 and the cohort born in 1973 included all pupils attending the last grade of compulsory school, respectively, in 1981 and in 1989. Their depressiveness and anxiousness were assessed by questionnaires at age 21 and again at age 43/39. Mental health at follow-up was related to exposure to unemployment during age years 21-25. Statistical significance of the cohort*exposure interactions from binary logistic regression analyses were used to assess the cohort differences in the mental health between Cohort65 and Cohort73, entering the labour market, respectively, during a boom and a recession. Compared to the unexposed, high exposure to unemployment at the age from 21 to 25 was associated to increased probability of poor mental health in the middle age in both in Cohort65 (odds ratio 2.19 [1.46-3.30] for anxiousness and 1.85 [1.25-2.74]for depressiveness) and in Cohort73 (odds ratio 2.13 [1.33-3.39] for anxiousness and 1.38 [0.89-2.14] for depressiveness). The differences between the cohorts also turned out as statistically non-significant. The scars of unemployment exposure onto future health seem to be rather insensitive to economic trades. Thus, at the population level this would mean that the long-term health costs that can be attributed to youth unemployment are more widespread in the generation that suffers of recession around the entry to the work life.

  20. Report of a study on the characteristics of the 'Clay of Boom' that are relevant in considering this clay layer package for the storage of nuclear waste; Rapportage van onderzoek aan eigenschappen van de Klei van Boom die relevant zijn bij de beschouwing van dit laagpakket voor opslag van kernafval

    Energy Technology Data Exchange (ETDEWEB)

    Brugge, J.V.M.; Vrouwe, B.J. [T and A Survey, Amsterdam (Netherlands)

    2010-12-15

    The Dutch government aims to store nuclear waste in the Dutch soil. Geological research organization T and A Survey mapped the areas that match with the demands of the Dutch government regarding underground storage of nuclear waste. These are areas in which the Clay layer of Boom has a minimal thickness of 100 meters and the depth of the top of the clay formation is at least 500 meters. [Dutch] De Nederlandse overheid wil kernafval ondergronds opslaan in de Nederlandse bodem. Geologisch onderzoeksbureau T and A Survey brengt de gebieden in kaart, die voldoen aan de door de overheid gestelde eisen voor mogelijke ondergrondse opslag van kernafval. Het gaat om gebieden waar de Boomse kleilaag een minimale dikte van 100 meter heeft en de diepte van de top van de kleiformatie minimaal 500 meter bedraagt.

  1. New Arenas of Engagement at the Water Governance-Climate Finance Nexus? An Analysis of the Boom and Bust of Hydropower CDM Projects in Vietnam

    Directory of Open Access Journals (Sweden)

    Mattijs Smits

    2014-10-01

    Full Text Available This article explores whether new arenas of engagement for water governance have been created and utilised following the implementation of the Clean Development Mechanism (CDM in large hydropower projects in Vietnam. Initial optimism for climate finance – in particular amongst Northern aid providers and private CDM consultants – resulted in a boom in registration of CDM hydropower projects in Vietnam. These plans, however, have since then busted. The article utilises a multi-scale and multi-place network governance analysis of the water governance-climate finance nexus, based on interviews with government officials, consultants, developers, NGOs, multilateral and international banks, and project-affected people at the Song Bung 2 and Song Bung 4 hydropower projects in Central Vietnam. Particular attention is paid to how the place-based nature of organisations shapes the ability of these actors to participate in decision-making. The article concludes that the CDM has had little impact on water governance in Vietnam at the project level in terms of carbon reduction (additionality or attaining sustainable development objectives. Furthermore, whilst climate finance has the potential to open new, more transparent and more accountable arenas of water governance, current arenas of the water governance-climate finance nexus are 'rendered technical', and therefore often underutilised and inaccessible to civil society and project-affected people.

  2. El círculo vicioso del turismo residencial: análisis de los factores locales del boom inmobiliario español

    Directory of Open Access Journals (Sweden)

    Hugo García Andreu

    2014-01-01

    Full Text Available Entre 1996 y 2006 España experimenta un boom inmobiliario sin precedentes que ha afectado principalmente a los municipios de litoral. Este proceso de intensa producción inmobiliaria ha estado sostenido sobre una igualmente intensa demanda internacional. Sin embargo, pasar de puntillas por el papel que han jugado las dinámicas e intereses locales en este proceso supone entender que los destinos han tenido un papel menos activo del que realmente han tenido. Desde una perspectiva relacional, el presente artículo destaca el papel que han jugado determinados factores locales en el proceso. Para ello, analiza de qué forma han interaccionado y se han retroalimentado positivamente factores como los elevados beneficios empresariales de la construcción, la descapitalización de sectores económicos tradicionales, la corrupción urbanística, la estacionalidad turística, el subregistro poblacional, la financiación de las administraciones locales y el escaso peso de las actividades vinculadas más directamente al turismo.

  3. The Boom of Electricity Demand in the Residential Sector in the Developing World and the Potential for Energy Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Letschert, Virginie; McNeil, Michael A.

    2008-05-13

    With the emergence of China as the world's largest energy consumer, the awareness of developing country energy consumption has risen. According to common economic scenarios, the rest of the developing world will probably see an economic expansion as well. With this growth will surely come continued rapid growth in energy demand. This paper explores the dynamics of that demand growth for electricity in the residential sector and the realistic potential for coping with it through efficiency. In 2000, only 66% of developing world households had access to electricity. Appliance ownership rates remain low, but with better access to electricity and a higher income one can expect that households will see their electricity consumption rise significantly. This paper forecasts developing country appliance growth using econometric modeling. Products considered explicitly - refrigerators, air conditioners, lighting, washing machines, fans, televisions, stand-by power, water heating and space heating - represent the bulk of household electricity consumption in developing countries. The resulting diffusion model determines the trend and dynamics of demand growth at a level of detail not accessible by models of a more aggregate nature. In addition, the paper presents scenarios for reducing residential consumption through cost-effective and/or best practice efficiency measures defined at the product level. The research takes advantage of an analytical framework developed by LBNL (BUENAS) which integrates end use technology parameters into demand forecasting and stock accounting to produce detailed efficiency scenarios, which allows for a realistic assessment of efficiency opportunities at the national or regional level. The past decades have seen some of the developing world moving towards a standard of living previously reserved for industrialized countries. Rapid economic development, combined with large populations has led to first China and now India to emerging as &apos

  4. Semiclassical dynamics

    International Nuclear Information System (INIS)

    Balazs, N.L.

    1979-01-01

    It is pointed out that in semiclassical dynamics one is encouraged to study the evolution of those curves in phase space which classically represent ensembles corresponding to wave functions. It is shown that the fixed points generate new time scales so that for times longer than the critical times, quantum dynamics will profoundly differ from classical dynamics. (P.L.)

  5. Dynamical Languages

    Science.gov (United States)

    Xie, Huimin

    The following sections are included: * Definition of Dynamical Languages * Distinct Excluded Blocks * Definition and Properties * L and L″ in Chomsky Hierarchy * A Natural Equivalence Relation * Symbolic Flows * Symbolic Flows and Dynamical Languages * Subshifts of Finite Type * Sofic Systems * Graphs and Dynamical Languages * Graphs and Shannon-Graphs * Transitive Languages * Topological Entropy

  6. Governing the transition to renewable energy: A review of impacts and policy issues in the small hydropower boom

    International Nuclear Information System (INIS)

    Kelly-Richards, Sarah; Silber-Coats, Noah; Crootof, Arica; Tecklin, David; Bauer, Carl

    2017-01-01

    The transition to renewable energy technologies raises new and important governance questions. With small hydropower (SHP) expanding as part of renewable energy and climate mitigation strategies, this review assesses its impacts and identifies escalating policy issues. To provide a comprehensive literature review of small hydropower, we evaluated over 3600 articles and policy documents. This review identified four major concerns: (1) confusion in small hydropower definitions is convoluting scholarship and policy-making; (2) there is a lack of knowledge and acknowledgement of small hydropower’s social, environmental, and cumulative impacts; (3) small hydropower’s promotion as a climate mitigation strategy can negatively affect local communities, posing contradictions for climate change policy; and (4) institutional analysis is needed to facilitate renewable energy integration with existing environmental laws to ensure sustainable energy development. For readers interested in small hydropower, we clarify areas of confusion in definition and explain the corresponding impacts for distinct system designs. For a broader readership, we situate small hydropower implementation within international trends of renewable energy development – the contradictory impacts of climate change policy, emerging dynamics in energy finance, and reliance on market mechanisms. Our paper provides a timely contribution to scholarship on small hydropower and the transition to renewable energy. - Highlights: • Confusion in small hydropower definitions is convoluting small hydropower debates. • Small hydropower’s negative impacts are largely overlooked in policy discussions. • Small hydropower exemplifies paradoxical problems with climate change policy. • Policies needed to integrate renewable energy development with national environmental institutions.

  7. Parametric Study of the Effect of Membrane Tension on Sunshield Dynamics

    Science.gov (United States)

    Ross, Brian; Johnston, John D.; Smith, James

    2002-01-01

    The NGST sunshield is a lightweight, flexible structure consisting of pretensioned membranes supported by deployable booms. The structural dynamic behavior of the sunshield must be well understood in order to predict its influence on observatory performance. A 1/10th scale model of the sunshield has been developed for ground testing to provide data to validate modeling techniques for thin film membrane structures. The validated models can then be used to predict the behaviour of the full scale sunshield. This paper summarizes the most recent tests performed on the 1/10th scale sunshield to study the effect of membrane preload on sunshield dynamics. Topics to be covered include the test setup, procedures, and a summary of results.

  8. Jumping Dynamics

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2013-01-01

    We propose an alternative paradigm to the conjectured Miransky scaling potentially underlying the physics describing the transition from the conformally broken to the conformally restored phase when tuning certain parameters such as the number of flavors in gauge theories. According to the new pa...... without particle interpretation. The jumping scenario, therefore, does not support a near-conformal dynamics of walking type. We will also discuss the impact of jumping dynamics on the construction of models of dynamical electroweak symmetry breaking....

  9. Dynamical systems

    CERN Document Server

    Sternberg, Shlomo

    2010-01-01

    Celebrated mathematician Shlomo Sternberg, a pioneer in the field of dynamical systems, created this modern one-semester introduction to the subject for his classes at Harvard University. Its wide-ranging treatment covers one-dimensional dynamics, differential equations, random walks, iterated function systems, symbolic dynamics, and Markov chains. Supplementary materials offer a variety of online components, including PowerPoint lecture slides for professors and MATLAB exercises.""Even though there are many dynamical systems books on the market, this book is bound to become a classic. The the

  10. Dynamics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Dynamics Lab replicates vibration environments for every Navy platform. Testing performed includes: Flight Clearance, Component Improvement, Qualification, Life...

  11. An empirical model of the Baltic Sea reveals the importance of social dynamics for ecological regime shifts.

    Science.gov (United States)

    Lade, Steven J; Niiranen, Susa; Hentati-Sundberg, Jonas; Blenckner, Thorsten; Boonstra, Wiebren J; Orach, Kirill; Quaas, Martin F; Österblom, Henrik; Schlüter, Maja

    2015-09-01

    Regime shifts triggered by human activities and environmental changes have led to significant ecological and socioeconomic consequences in marine and terrestrial ecosystems worldwide. Ecological processes and feedbacks associated with regime shifts have received considerable attention, but human individual and collective behavior is rarely treated as an integrated component of such shifts. Here, we used generalized modeling to develop a coupled social-ecological model that integrated rich social and ecological data to investigate the role of social dynamics in the 1980s Baltic Sea cod boom and collapse. We showed that psychological, economic, and regulatory aspects of fisher decision making, in addition to ecological interactions, contributed both to the temporary persistence of the cod boom and to its subsequent collapse. These features of the social-ecological system also would have limited the effectiveness of stronger fishery regulations. Our results provide quantitative, empirical evidence that incorporating social dynamics into models of natural resources is critical for understanding how resources can be managed sustainably. We also show that generalized modeling, which is well-suited to collaborative model development and does not require detailed specification of causal relationships between system variables, can help tackle the complexities involved in creating and analyzing social-ecological models.

  12. Fluid Dynamics

    DEFF Research Database (Denmark)

    Brorsen, Michael

    These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University.......These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University....

  13. Molecular dynamics

    NARCIS (Netherlands)

    Bergstra, J.A.; Bethke, I.

    2002-01-01

    Molecular dynamics is a model for the structure and meaning of object based programming systems. In molecular dynamics the memory state of a system is modeled as a fluid consisting of a collection of molecules. Each molecule is a collection of atoms with bindings between them. A computation is

  14. Discrete dynamics versus analytic dynamics

    DEFF Research Database (Denmark)

    Toxværd, Søren

    2014-01-01

    For discrete classical Molecular dynamics obtained by the “Verlet” algorithm (VA) with the time increment h there exists a shadow Hamiltonian H˜ with energy E˜(h) , for which the discrete particle positions lie on the analytic trajectories for H˜ . Here, we proof that there, independent of such a......For discrete classical Molecular dynamics obtained by the “Verlet” algorithm (VA) with the time increment h there exists a shadow Hamiltonian H˜ with energy E˜(h) , for which the discrete particle positions lie on the analytic trajectories for H˜ . Here, we proof that there, independent...... of such an analytic analogy, exists an exact hidden energy invariance E * for VA dynamics. The fact that the discrete VA dynamics has the same invariances as Newtonian dynamics raises the question, which of the formulations that are correct, or alternatively, the most appropriate formulation of classical dynamics....... In this context the relation between the discrete VA dynamics and the (general) discrete dynamics investigated by Lee [Phys. Lett. B122, 217 (1983)] is presented and discussed....

  15. Record dynamics

    DEFF Research Database (Denmark)

    Robe, Dominic M.; Boettcher, Stefan; Sibani, Paolo

    2016-01-01

    When quenched rapidly beyond their glass transition, colloidal suspensions fall out of equilibrium. The pace of their dynamics then slows down with the system age, i.e., with the time elapsed after the quench. This breaking of time translational invariance is associated with dynamical observables......-facto irreversible and become increasingly harder to achieve. Thus, a progression of record-sized dynamical barriers are traversed in the approach to equilibration. Accordingly, the statistics of the events is closely described by a log-Poisson process. Originally developed for relaxation in spin glasses...

  16. Galactic dynamics

    CERN Document Server

    Binney, James

    2008-01-01

    Since it was first published in 1987, Galactic Dynamics has become the most widely used advanced textbook on the structure and dynamics of galaxies and one of the most cited references in astrophysics. Now, in this extensively revised and updated edition, James Binney and Scott Tremaine describe the dramatic recent advances in this subject, making Galactic Dynamics the most authoritative introduction to galactic astrophysics available to advanced undergraduate students, graduate students, and researchers. Every part of the book has been thoroughly overhauled, and many section

  17. Structural Dynamics

    International Nuclear Information System (INIS)

    Kim, Du Gi

    2005-08-01

    This book introduces summary of structural dynamics, the reason of learning of structural dynamics, single-degree of freedom system, simple harmonic vibration and application, numerical analysis method, such as time domain and frequency domain and nonlinear system, multi-degree of freedom system random vibration over discrete distribution, continuous distribution and extreme value distribution, circumstance vibration, earth quake vibration, including input earthquake, and earthquake-resistant design and capacity spectrum method, wind oscillation wave vibration, vibration control and maintenance control.

  18. An experimental study of the dynamics of saltation within a three-dimensional framework

    Science.gov (United States)

    O'Brien, Patrick; McKenna Neuman, Cheryl

    2018-04-01

    Our understanding of aeolian sand transport via saltation lacks an experimental determination of the particle borne kinetic energy partitioned into 3 dimensions relative to the mean flow direction. This in turn creates a disconnect between global wind erosion estimates and particle scale processes. The present study seeks to address this deficiency through an extended analysis of data obtained from a series of particle tracking velocimetry experiments conducted in a boundary layer wind tunnel under transport limited conditions. Particle image diameter, as it appeared within each camera frame, was extensively calibrated against that obtained by sieving, and the ballistic trajectories detected were disassembled into discrete particle image pairs whose distribution and dynamics were then examined in vertical profile with sub-millimeter resolution. The vertical profile of the wind aligned particle transport rate was found to follow a power relation within 10 mm of the bed surface. The exponent of this power function changes with increasing spanwise angle (θ) to produce a family of curves representing particle diffusion in 3 dimensions. Particle mass was found to increase with θ, and the distribution of the total particle kinetic energy was found to be very similar to that for the particle concentration. The spanwise component of the kinetic energy of a saltating particle peaks at θ = 45°, with the stream-aligned component an order of magnitude higher in value. Low energy, splashed particles near the bed account for a majority of the kinetic energy distributed throughout the particle cloud, regardless of their orientation.

  19. From Building Boom to Bust

    DEFF Research Database (Denmark)

    Vestergaard, Hedvig; Haagerup, Christian Deichmann

    2016-01-01

    until 2005–2007. Urban sprawl and overinvestment in business premises and housing were important risks to be considered. The high economic activity also led to an increase in the cost of housing and hence to affordability problems in major cities. Many new urban quarters and towns came into planning...

  20. Refinery boom in Southeast Asia

    International Nuclear Information System (INIS)

    Gruson, J.F.; Virondaud, C.

    1996-01-01

    The Asia demand for oil is increasing dramatically, particularly in the non OECD countries, which represent, today more than 15 % of the world oil market. The expected economic growth in these areas should contribute to a rise in oil demand by about 5.4 per year and hence to a significant increase of this share to 25 % in 2010; virtually a large part of this evolution will come from the transportation sector. The proceeding investments of the regional, refining industry are very high (some evaluations come to around 140 billion of dollars), all the more the protection of the environment takes an increasing significant place. Accordingly the most important challenge to be taken up by these countries will be to mobilize long term fundings to develop and adapt the capabilities of the refineries to meet the growth of gasoline and gas oil demand. The contribution of private operators or capital will be necessary, but will depend strongly on refining margin improvement and on progress of free market areas announced by several countries. (authors)

  1. Thai petrochemical boom on track

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that Thailand continues to mark progress on the ambitious expansion of its petrochemical industry. Among recent developments: The outlook for Thailand's troubled worldscale aromatics project has improved with a major cut in its estimated cost. In addition, the project apparently has drawn the interest of other companies seeking a possible equity stake. Amoco Chemical Co., which lost a tender to build a worldscale purified terephathalic acid (PTA) complex in Thailand to Taiwan's Tuntex Co., is reviving its bid with a proposal similar to its earlier one. Amoco contends there will be enough demand to warrant a second PTA plant in Thailand. Tuntex is negotiating with several business groups to take part in its $333 million, 350,000 ton/year PTA project in Thailand. Tuntex is soliciting interest from a number of Thai companies, including Bangkok Bank and the Saha Union industrial conglomerate to acquire portions of the 51% interest in the project earmarked for Thai shareholders. The firm also is negotiating with a number of Japanese companies with whom it has long trade ties, including Mitsui and Co. and Marubeni Corp. to acquire part of the 49% foreign shareholding in the project. Thai Olefins Co. (TOC) marked further progress with feedstock contracts and financing arrangements for its proposed $720 million olefins plant, part of Thailand's second worldscale petrochemical complex (NPC II). Indian industrial giant Birla proposed a $20 million ethylene glycol (EG) project in Thailand

  2. Uranium producers foresee new boom

    International Nuclear Information System (INIS)

    McIntyre, H.

    1979-01-01

    The status of uranium production in Canada is reviewed. Uranium resources in Saskatchewan and Ontario are described and the role of the Cluff Lake inquiry in securing a government decision in favour of further uranium development is mentioned. There have been other uranium strikes near Kelowna, British Columbia and in the Northwest Territories. Increasing uranium demand and favourable prices are making the development of northern resources economically attractive. In fact, all uranium currently produced has been committed to domestic and export contracts so that there is considerable room for expanding the production of uranium in Canada. (T.I.)

  3. A consistent phenomenological model for natural organic matter linked migration of Cm(III), Pu(III/IV), Np(IV), Tc(IV) and Pa(V) in the Boom Clay

    International Nuclear Information System (INIS)

    Martens, E.; Maes, N.; Bruggeman, C.; Van Gompel, M.

    2010-01-01

    Document available in extended abstract form only. As Natural Organic Matter (NOM) may modify/enhance the mobility of radionuclides (RNs) through complexation or colloidal interactions, it is essential to evaluate the impact of these processes before performing safety assessments aiming at demonstrating the suitability of deep-seated clayey formations for geological disposal of radioactive waste. Column migration experiments with Cm, Pu, Np, Tc and Pa in Boom Clay, initiated about 10 years ago, showed strikingly similar features despite their different chemical speciation. On a relative short time, these RNs began percolating through the clay core until a constant concentration at the outlet side was reached. As most of the aqueous forms of these RNs are supposed to sorb strongly onto the Boom Clay solid phase, it was assumed that their relative fast transport was due to colloids (either intrinsic colloids or NOM-colloids). The constant concentration percolating from the core was thought to result from a solubility limiting phase precipitated at the source position. However, the concentrations in the percolate were systematically lower than the thermodynamic calculated solubilities, and all the more, complexation to NOM would likely result in an increased RN concentration. Although these curves could be modelled by a simple diffusion-advection relationship with linear sorption, they could not be backed up by a mechanistic understanding. As the concentration in the percolate remained constant for many years, the RN-species eluting from the core are assumed to be well in equilibrium with the Boom Clay geochemical conditions. Therefore, they were used as input source (constant concentration boundary condition) for a migration experiment through a fresh clay core (i.e. the outlet of a first cell was coupled to the inlet of a second cell). The measured concentrations at the outlet of the second clay core also reached a constant value, but this value is about one order

  4. Dynamic Bifurcations

    CERN Document Server

    1991-01-01

    Dynamical Bifurcation Theory is concerned with the phenomena that occur in one parameter families of dynamical systems (usually ordinary differential equations), when the parameter is a slowly varying function of time. During the last decade these phenomena were observed and studied by many mathematicians, both pure and applied, from eastern and western countries, using classical and nonstandard analysis. It is the purpose of this book to give an account of these developments. The first paper, by C. Lobry, is an introduction: the reader will find here an explanation of the problems and some easy examples; this paper also explains the role of each of the other paper within the volume and their relationship to one another. CONTENTS: C. Lobry: Dynamic Bifurcations.- T. Erneux, E.L. Reiss, L.J. Holden, M. Georgiou: Slow Passage through Bifurcation and Limit Points. Asymptotic Theory and Applications.- M. Canalis-Durand: Formal Expansion of van der Pol Equation Canard Solutions are Gevrey.- V. Gautheron, E. Isambe...

  5. Dynamical Groups

    Science.gov (United States)

    Paldus, Josef

    The well known symmetry (invariance, degeneracy) dynamical groups or algebras of quantum mechanical Hamiltonians provide quantum numbers (conservation laws, integrals of motion) for state labeling and the associated selection rules. In addition, it is often advantageous to employ much larger groups, referred to as the dynamical groups (noninvariance groups, dynamical algebras, spectrum generating algebras), which may or may not be the invariance groups of the studied system [4.1,2,3,4,5,6,7]. In all known cases, they are Lie groups (LGs), or rather corresponding Lie algebras (LAs), and one usually requires that all states of interest of a system be contained in a single irreducible representation (irrep). Likewise, one may require that the Hamiltonian be expressible in terms of the Casimir operators of the corresponding universal enveloping algebra [4.8,9]. In a weaker sense, one regards any group (or corresponding algebra) as a dynamical group if the Hamiltonian can be expressed in terms of its generators [4.10,11,12]. In nuclear physics, one sometimes distinguishes exact (baryon number preserving), almost exact (e.g., total isospin), approximate (e.g., SU(3) of the "eightfold way") and model (e.g., nuclear shell model) dynamical symmetries [4.13]. The dynamical groups of interest in atomic and molecular physics can be conveniently classified by their topological characteristic of compactness. Noncompact LGs (LAs) generally arise in simple problems involving an infinite number of bound states, while those involving a finite number of bound states (e.g., molecular vibrations or ab initio models of electronic structure) exploit compact LG's.

  6. Development of comprehensive and integrated models for inertial fusion cavity dynamics

    International Nuclear Information System (INIS)

    Hassanein, A.; Morozov, V.

    2002-01-01

    The chamber walls in inertial fusion energy (IFE) reactors are exposed to harsh conditions following each target implosion. Key issues of the cyclic IFE operation include intense photon and ion deposition, wall thermal and hydrodynamic evolution, wall erosion and fatigue lifetime, and chamber clearing and evacuation to ensure chamber conditions prior to target implosion. Several methods for wall protection have been proposed in the past, each having its own advantages and disadvantages. These methods include bare walls, gas-filled cavities, and liquid walls/jets. We have developed detailed models for reflected laser light, emitted photon, and target debris deposition and interaction with chamber components and implemented them in the comprehensive HEIGHTS software package. The hydrodynamic response of gas-filled cavities and photon radiation transport of the deposited energy has been calculated using new and advanced numerical techniques. Fragmentation models of liquid jets as a result of the deposited energy have also been developed, and the impact on chamber clearing dynamics has been evaluated. The focus of this study is to critically assess the reliability and the dynamic response of chamber walls in various proposed protection methods in IFE systems. Of particular concern is the effect on wall erosion lifetime of various erosion mechanisms, such as vaporization, chemical and physical sputtering, melt/liquid splashing and explosive erosion, and fragmentation of liquid walls. Mass loss and fragmentation in the form of macroscopic particles can be much larger than mass loss due to surface vaporization and sputtering and have not been properly considered in past studies as part of the overall cavity response and reestablishment. This effect may significantly alter cavity dynamics and power requirements

  7. Dynamical systems

    CERN Document Server

    Birkhoff, George D

    1927-01-01

    His research in dynamics constitutes the middle period of Birkhoff's scientific career, that of maturity and greatest power. -Yearbook of the American Philosophical Society The author's great book€¦is well known to all, and the diverse active modern developments in mathematics which have been inspired by this volume bear the most eloquent testimony to its quality and influence. -Zentralblatt MATH In 1927, G. D. Birkhoff wrote a remarkable treatise on the theory of dynamical systems that would inspire many later mathematicians to do great work. To a large extent, Birkhoff was writing about his o

  8. Glassy Dynamics

    DEFF Research Database (Denmark)

    Jensen, Henrik J.; Sibani, Paolo

    2007-01-01

    The term glassy dynamics is often used to refer to the extremely slow relaxation observed in several types of many component systems. The time span needed to reach a steady, time independent, state will typically be far beyond experimentally accessible time scales. When melted alloys are cooled...... down they typically do not enter a crystalline ordered state. Instead the atoms retain the amorphous arrangement characteristic of the liquid high temperature phase while the mobility of the molecules decreases very many orders of magnitude. This colossal change in the characteristic dynamical time...

  9. Forest dynamics.

    Science.gov (United States)

    Frelich, Lee

    2016-01-01

    Forest dynamics encompass changes in stand structure, species composition, and species interactions with disturbance and environment over a range of spatial and temporal scales. For convenience, spatial scale is defined as individual tree, neighborhood, stand, and landscape. Whether a given canopy-leveling disturbance will initiate a sequence of development in structure with little change in composition or initiate an episode of succession depends on a match or mismatch, respectively, with traits of the dominant tree species that allow the species to survive disturbance. When these match, certain species-disturbance type combinations lock in a pattern of stand and landscape dynamics that can persist for several generations of trees; thus, dominant tree species regulate, as well as respond to, disturbance. A complex interaction among tree species, neighborhood effects, disturbance type and severity, landform, and soils determines how stands of differing composition form and the mosaic of stands that compose the landscape. Neighborhood effects (e.g., serotinous seed rain, sprouting, shading, leaf-litter chemistry, and leaf-litter physical properties) operate at small spatial extents of the individual tree and its neighbors but play a central role in forest dynamics by contributing to patch formation at stand scales and dynamics of the entire landscape. Dominance by tree species with neutral to negative neighborhood effects leads to unstable landscape dynamics in disturbance-prone regions, wherein most stands are undergoing succession; stability can only occur under very low-severity disturbance regimes. Dominance by species with positive effects leads to stable landscape dynamics wherein only a small proportion of stands undergo succession at any one time. Positive neighborhood effects are common in temperate and boreal zones, whereas negative effects are more common in tropical climates. Landscapes with positive dynamics have alternate categories of dynamics

  10. Propulsion System Dynamic Modeling of the NASA Supersonic Concept Vehicle for AeroPropulsoServoElasticity

    Science.gov (United States)

    Kopasakis, George; Connolly, Joseph W.; Seiel, Jonathan

    2016-01-01

    A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report

  11. CERN Fellows, don’t splash that cash!

    CERN Multimedia

    Anaïs Schaeffer

    2013-01-01

    When their CERN contracts expire and they leave the Organization, Fellows recoup the amounts paid into the Pension Fund by and for them every month. If they invest this money well, right from the outset, it can grow into a nice little nest-egg by the time they reach retirement age.   As employed members of the CERN personnel, Fellows are members of the Organization’s Pension Fund. Accordingly, a specific amount is withheld from their salary every month (see first box) and, as the months go by, this gradually accumulates into their transfer value (i.e. their capital). When their contracts expire, Fellows may opt to transfer that money directly into another pension fund (subject to the national laws of the destination country and, unfortunately, not possible everywhere), or take it in cash. This is because only employed members of the personnel who have at least five years of service with the Organization are entitled to remain beneficiaries of the CERN Pension Fund for life*. But the capi...

  12. Bore-Soliton-Splash: van spektakel naar oceaangolf

    NARCIS (Netherlands)

    Bokhove, Onno; Gagarina, Elena; Zweers, Wout; Thornton, Anthony Richard

    2011-01-01

    Ons nieuwe universiteitsplein heeft een magnifieke golfgoot (figuur 1). Door drie professoren afzonderlijk was ons midden september 2010 gevraagd om een soliton te maken in deze goot om het plein feestelijk te openen. Een soliton is een enkelvoudige golf, een gelokaliseerde opéénhoping van zich snel

  13. Risk of blood splashes to the eye during surgery

    African Journals Online (AJOL)

    2009-02-25

    Feb 25, 2009 ... The prevalence of blood-borne diseases such as hepatitis. B, hepatitis C and HIV is increasing globally. Sub-Saharan. Africa is one of the worst-affected regions. The risk of infection from these blood-borne pathogens has become a significant occupational hazard for many categories of health care workers ...

  14. Blood splash from different diathermy instruments during tonsillectomy.

    Science.gov (United States)

    Hanna, B C; Thompson, P; Smyth, C; Gallagher, G

    2006-11-01

    To compare the potential risk of blood contamination of the surgeon's conjunctiva during tonsillectomy using disposable bipolar diathermy and reusable monopolar diathermy. A prospective, single-blind, randomized, controlled trial. Elective tonsillectomy was performed using either disposable bipolar diathermy or reusable monopolar diathermy. The operating surgeon wore a ViewsafeTM protective eyeshield which was later examined under an operating microscope by a blinded observer and the number of blood spots counted. One hundred and sixty-eight patients were enrolled. The relative risk of conjunctival contamination of the surgeon using disposable bipolar diathermy was 2.8 times that with reusable monopolar diathermy (chi-squared test, p blood splatter. The use of disposable bipolar diathermy for haemostasis during tonsillectomy poses a greater risk of conjunctival contamination for the surgeon than using reusable monopolar diathermy.

  15. Splash, pop, sizzle: Information processing with phononic computing

    International Nuclear Information System (INIS)

    Sklan, Sophia R.

    2015-01-01

    Phonons, the quanta of mechanical vibration, are important to the transport of heat and sound in solid materials. Recent advances in the fundamental control of phonons (phononics) have brought into prominence the potential role of phonons in information processing. In this review, the many directions of realizing phononic computing and information processing are examined. Given the relative similarity of vibrational transport at different length scales, the related fields of acoustic, phononic, and thermal information processing are all included, as are quantum and classical computer implementations. Connections are made between the fundamental questions in phonon transport and phononic control and the device level approach to diodes, transistors, memory, and logic. 

  16. Risk of blood splashes to the eye during surgery

    African Journals Online (AJOL)

    2009-02-25

    Feb 25, 2009 ... B, hepatitis C and HIV is increasing globally. Sub-Saharan ... infection from these blood-borne pathogens has become a significant .... cesarean section. Med Sci Monit 2006; 12(2): CR94-97. 2. Fitch KM, Alvarez IP, Medina RDA, et al. Occupational transmission of. HIV in health care workers. A review.

  17. Structural dynamics

    CERN Document Server

    Strømmen, Einar N

    2014-01-01

    This book introduces to the theory of structural dynamics, with focus on civil engineering structures that may be described by line-like beam or beam-column type of systems, or by a system of rectangular plates. Throughout this book the mathematical presentation contains a classical analytical description as well as a description in a discrete finite element format, covering the mathematical development from basic assumptions to the final equations ready for practical dynamic response predictions. Solutions are presented in time domain as well as in frequency domain. Structural Dynamics starts off at a basic level and step by step brings the reader up to a level where the necessary safety considerations to wind or horizontal ground motion induced dynamic design problems can be performed. The special theory of the tuned mass damper has been given a comprehensive treatment, as this is a theory not fully covered elsewhere. For the same reason a chapter on the problem of moving loads on beams has been included.

  18. Coastal Dynamics

    NARCIS (Netherlands)

    Roelvink, J.A.; Steetzel, H.J.; Bliek, A.; Rakhorst, H.D.; Roelse, P.; Bakker, W.T.

    1998-01-01

    This book deals on "Coastal Dynamics", which will be defined in a narrow sense as a mathematical theory, which starts from given equations of motion for the sediment, which leads with the continuity equation and given boundary conditions to a calculated (eventually schematized) coastal topography,

  19. Random dynamics

    International Nuclear Information System (INIS)

    Bennett, D.L.; Brene, N.; Nielsen, H.B.

    1986-06-01

    The goal of random dynamics is the derivation of the laws of Nature as we know them (standard model) from inessential assumptions. The inessential assumptions made here are expressed as sets of general models at extremely high energies: gauge glass and spacetime foam. Both sets of models lead tentatively to the standard model. (orig.)

  20. Dynamic Pricing

    DEFF Research Database (Denmark)

    Sharifi, Reza; Anvari-Moghaddam, Amjad; Fathi, S. Hamid

    2017-01-01

    Dynamic pricing scheme, also known as real-time pricing (RTP), can be more efficient and technically beneficial than the other price-based schemes (such as flat-rate or time-of-use (TOU) pricing) for enabling demand response (DR) actions. Over the past few years, advantages of RTP-based schemes h...

  1. Classical dynamics

    CERN Document Server

    Greenwood, Donald T

    1997-01-01

    Graduate-level text for science and technology students provides strong background in the more abstract and intellectually satisfying areas of dynamical theory. Topics include d'Alembert's principle and the idea of virtual work, Hamilton's equations, Hamilton-Jacobi theory, canonical transformations, more. Problems and references at chapter ends.

  2. Cybersecurity Dynamics

    Science.gov (United States)

    2014-08-20

    Vision: Cybersecurity Dynamics Foundation for the Science of Cybersecurity Cryptography Intrusion & Malware Detection Access Control TPM MTD...Science of Cybersecurity Cryptography Intrusion & Malware Detection Access Control TPM MTD Security Policy Security Architecture Attack...for the Science of Cybersecurity Cryptography Intrusion & Malware Detection Access Control TPM MTD Security Policy Security Architecture

  3. Expansion dynamics

    International Nuclear Information System (INIS)

    Knoll, J.

    1985-10-01

    A quantum dynamical model is suggested which describes the expansion and disassembly phase of highly excited compounds formed in energetic heavy-ion collisions. First applications in two space and one time dimensional model world are discussed and qualitatively compared to standard freeze-out concepts. (orig.)

  4. Dynamic Assessment.

    Science.gov (United States)

    Schoel, Jim

    1998-01-01

    Adventure therapists are often asked to assess clients in a manner that differs from their therapeutic approach, resulting in assessment being perceived as burdensome. Project Adventure's Decision Tree combines assessment with activity selection to create a dynamic tool that is responsive to group, individual, and leader needs. Example focuses on…

  5. Membrane dynamics

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    Current topics include membrane-protein interactions with regard to membrane deformation or curvature sensing by BAR domains. Also, we study the dynamics of membrane tubes of both cells and simple model membrane tubes. Finally, we study membrane phase behavior which has important implications...

  6. Responses of Raptorial Birds to Low Level Military Jets and Sonic Booms: Results of the 1980-1981 Joint U.S. Air Force-U.S. Fish and Wildlife Service Study

    Science.gov (United States)

    Ellis, D.H.

    1981-01-01

    Summary: For this study, we gathered several kinds of data to determine the likely effects of low level jets and sonic booms on nesting Peregrine Falcons and other raptors. We directly observed responses to worst case stimulus loads: responses to extremely frequent and extremely nearby jet aircraft were often minimal, seldom significant and never associated with reproductive failure. Likewise, responses to real and simulated sonic booms were often minimal and never productivity limiting. In addition to directly observing behavioral responses, in 1981 we invited jet passes at four Prairie Falcon eyries during courtship and incubation when the adults were most likely to abandon, on an ad libitum basis. All four eyries fledged young. Nesting success and site reoccupancy rates were high for all eyries. In tests of two relatively naive captive Peregrine Falcons, we failed to detect significantly negative responses. Typically the birds either quickly resumed feeding or other activities within a few seconds following a pass or boom. The female falcon repeatedly made hunting forays as jets swept overhead. From heart rate (HR) data taken via a telemetering egg during incubation at a wild Prairie Falcon eyrie, we determined that stimulus induced HR alterations were comparable to rate changes of the birds settling to incubate following flight. No significant long term responses were identified. The falcons successfully fledged two young even with the more disruptive activities associated with entering the eyrie three times to position and recover the telemetering eggs. Significantly, birds ofprey of several genera commonly nest in the supersonic military operations areas in southern Arizona. In addition, raptor eyries are frequently found at locations where low level jet traffic naturally concentrates. For example, Prairie Falcon Site 11 is directly on the approach path to strafing and bombing targets. Prairie Falcon Site 1 is in a narrow canyon through which A-10 aircraft

  7. Proposta metodológica para avaliação de controlador automático de seções e pulverização Proposed methodology for evaluation of automatic controller of boom sections and spray

    Directory of Open Access Journals (Sweden)

    Étore F Reynaldo

    2011-02-01

    Full Text Available Na aplicação de produtos fitossanitários, a utilização de equipamentos que controlam automaticamente as seções da barra e a pulverização já é realidade; entretanto, ainda não há resultados que demonstrem a sua eficácia. Por esse motivo, este trabalho teve por finalidade desenvolver uma metodologia para a avaliação de um equipamento que controla automaticamente as seções e a pulverização. Avaliou-se um controlador automático de seções e pulverização de mercado, e, para tanto, foram utilizados três níveis de acurácia do sinal de GPS (algoritmo interno, SBAS e RTK, três ângulos para a simulação de entrada e saída da barra de pulverização em relação à borda do talhão (0; 45 e 60º e três velocidades de trabalho (1,66; 5,00 e 8,33 m s-1. A metodologia proposta possibilitou a determinação dos tempos e distâncias de abertura e fechamento das seções. Os coeficientes de variação para os tempos e distâncias de abertura e fechamento das seções indicaram uma variação considerável. Houve interações significativas em função do tipo de sinal de GPS. A configuração recomendada pelo fabricante e adotada para a avaliação do controlador automático de seções e pulverização não atende a todas as situações simuladas.In the application of pesticides, the use of equipment that automatically controls the sections of the boom and the spray is already reality. However, there are no results to show its effectiveness. Therefore, this work was to develop a methodology for the evaluation of equipments which automatically controls the boom sections and the spraying pattern. A commercial automatic controller of boom spraying sections was evaluated using three levels of GPS accuracy (internal algorithm, SBAS and RTK, three angles for the simulation of entry and exit of the spray bar on field edges (0, 45 and 60 º and three forward speeds (1.66, 5.00 and 8.33 m s-1. The proposed methodology allowed the

  8. Applied dynamics

    CERN Document Server

    Schiehlen, Werner

    2014-01-01

    Applied Dynamics is an important branch of engineering mechanics widely applied to mechanical and automotive engineering, aerospace and biomechanics as well as control engineering and mechatronics. The computational methods presented are based on common fundamentals. For this purpose analytical mechanics turns out to be very useful where D’Alembert’s principle in the Lagrangian formulation proves to be most efficient. The method of multibody systems, finite element systems and continuous systems are treated consistently. Thus, students get a much better understanding of dynamical phenomena, and engineers in design and development departments using computer codes may check the results more easily by choosing models of different complexity for vibration and stress analysis.

  9. Delta Dynamics

    DEFF Research Database (Denmark)

    Bendixen, Mette

    A warming climate affects the entire planet, but the Arctic experience a warming that is faster than elsewhere in the world. This influences several processes affecting the evolution of the Arctic coast, and increasing erosion rates are detected throughout large parts of these high-latitude coasts...... to sandy beaches, marshes and deltas. This PhD thesis investigates coastal evolution with a special focus on changes in deltaic environments both during the Holocene and in a modern changing climate. The first part of the thesis (Paper 1 and 2) focus on detailed processes affecting delta evolution...... of a fjord and the second type is a wider fan-shaped open delta. Most deltas are directly coupled to the Greenland Ice Sheet or local icecaps and are highly influenced by the dynamics in the catchments. It is demonstrated how a modern changing climate directly affects delta dynamics, and that Greenlandic...

  10. Étude des interactions mécaniques et physico-chimiques entre les argiles et les fluides de forage. Application à l'argile de Boom (Belgique A Study O the Mechanical and Physicochemical Interactions Between the Clay Materials and the Drilling Fluids. Application to the Boom Clay (Belgium

    Directory of Open Access Journals (Sweden)

    Tshibangu J. P.

    2006-11-01

    Full Text Available Ce travail est motivé par les problèmes posés par la stabilité des puits forés dans des formations argileuses avec des boues de forage à base d'eau. En effet, les roches argileuses ou argilites (shales en anglais ont la propriété d'absorber de l'eau, entraînant ainsi la déstabilisation des puits, soit par gonflement de certaines espèces minérales, soit par annulation de la pression de soutènement de la paroi par suite de la modification de la pression de pore. La déstabilisation peut être purement mécanique avec une plastification entraînant un cavage du trou, ou dépendre essentiellement des interactions physicochimiques entre le fluide de forage et l'argile. Le but de ce travail est donc de mettre expérimentalement en évidence les mécanismes susceptibles de jouer un rôle dans les phénomènes évoqués, et de tenter de quantifier l'importance de ces mécanismes pour en tenir compte dans les modèles de calcul. Le système expérimental que nous utilisons est basé sur une cellule triaxiale perméable aux rayons X, et donc destinée à un fonctionnement sous scanner (tomographie. Ce système, conçu et construit à l'Institut Français du Pétrole (IFP, est nouveau et nous avons contribué dans le cadre de ce travail à sa mise au point. La démarche consiste à mettre un échantillon d'argile sous confinement au contact avec un fluide de composition déterminée et à voir si les composants de ce fluide migrent dans l'argile ou non. Bien entendu, la tomographie ne permet que d'avoir des densités globales avec des résolutions de loin supérieures à la dimension du pore d'un matériau argileux sous confinement. Il est donc évident que les indications fournies par cette méthode doivent être complétées avec d'autres types de méthodes pour arriver à une étude sélective de la migration des éléments en solution. Pour ce qui concerne le matériau, notre choix s'est porté sur l'argile de Boom en Belgique, d'une part

  11. Socio-ecological dynamics of Caribbean coral reef ecosystems and conservation opinion propagation.

    Science.gov (United States)

    Thampi, Vivek A; Anand, Madhur; Bauch, Chris T

    2018-02-07

    The Caribbean coral reef ecosystem has experienced a long history of deterioration due to various stressors. For instance, over-fishing of parrotfish - an important grazer of macroalgae that can prevent destructive overgrowth of macroalgae - has threatened reef ecosystems in recent decades and stimulated conservation efforts such as the formation of marine protected areas. Here we develop a mathematical model of coupled socio-ecological interactions between reef dynamics and conservation opinion dynamics to better understand how natural and human factors interact individually and in combination to determine coral reef cover. We find that the coupling opinion and reef systems generates complex dynamics that are difficult to anticipate without use of a model. For instance, instead of converging to a stable state of constant coral cover and conservationist opinion, the system can oscillate between low and high live coral cover as human opinion oscillates in a boom-bust cycle between complacency and concern. Out of various possible parameter manipulations, we also find that raising awareness of coral reef endangerment best avoids counter-productive nonlinear feedbacks and always increases and stabilizes live coral reef cover. In conclusion, an improved understanding of coupled opinion-reef dynamics under anthrogenic stressors is possible using coupled socio-ecological models, and such models should be further researched.

  12. Hamiltonian dynamics

    CERN Document Server

    Vilasi, Gaetano

    2001-01-01

    This is both a textbook and a monograph. It is partially based on a two-semester course, held by the author for third-year students in physics and mathematics at the University of Salerno, on analytical mechanics, differential geometry, symplectic manifolds and integrable systems. As a textbook, it provides a systematic and self-consistent formulation of Hamiltonian dynamics both in a rigorous coordinate language and in the modern language of differential geometry. It also presents powerful mathematical methods of theoretical physics, especially in gauge theories and general relativity. As a m

  13. Complex dynamics

    CERN Document Server

    Carleson, Lennart

    1993-01-01

    Complex dynamics is today very much a focus of interest. Though several fine expository articles were available, by P. Blanchard and by M. Yu. Lyubich in particular, until recently there was no single source where students could find the material with proofs. For anyone in our position, gathering and organizing the material required a great deal of work going through preprints and papers and in some cases even finding a proof. We hope that the results of our efforts will be of help to others who plan to learn about complex dynamics and perhaps even lecture. Meanwhile books in the field a. re beginning to appear. The Stony Brook course notes of J. Milnor were particularly welcome and useful. Still we hope that our special emphasis on the analytic side will satisfy a need. This book is a revised and expanded version of notes based on lectures of the first author at UCLA over several \\Vinter Quarters, particularly 1986 and 1990. We owe Chris Bishop a great deal of gratitude for supervising the production of cour...

  14. Premelting Dynamics

    Science.gov (United States)

    Wettlaufer, J. S.; Grae Worster, M.

    2006-01-01

    When the free surfaces of most solids approach their bulk melting temperatures from below, the molecular structure of the material gives way to a disordered structure with some attributes of both the solid and liquid phases. When the temperature is sufficiently close to that of bulk transition, the surface melts and literally flows as a viscous fluid. This phenomenon, called interfacial premelting, lies at the heart of the microscopic theory of melting of solid matter, and captures the interest of condensed matter physicists and physical chemists alike. The process is ubiquitous and responsible for a wide range of consequences in materials with biological, geophysical, and technological significance. Because such systems are often exposed to spatial or temporal variations in thermodynamic forcing, there are a host of fluid mechanical phenomena that result from this underlying melting behavior. The fluid dynamics of unfrozen surfaces holds clues for understanding the bulk behavior of polycrystalline materials, from Earth's mantle to the stratosphere and beyond. In this review we focus on the fluid dynamical consequences of the premelting of solids.

  15. Population dynamics

    Directory of Open Access Journals (Sweden)

    Cooch, E. G.

    2004-06-01

    Full Text Available Increases or decreases in the size of populations over space and time are, arguably, the motivation for much of pure and applied ecological research. The fundamental model for the dynamics of any population is straightforward: the net change over time in the abundance of some population is the simple difference between the number of additions (individuals entering the population minus the number of subtractions (individuals leaving the population. Of course, the precise nature of the pattern and process of these additions and subtractions is often complex, and population biology is often replete with fairly dense mathematical representations of both processes. While there is no doubt that analysis of such abstract descriptions of populations has been of considerable value in advancing our, there has often existed a palpable discomfort when the ‘beautiful math’ is faced with the often ‘ugly realities’ of empirical data. In some cases, this attempted merger is abandoned altogether, because of the paucity of ‘good empirical data’ with which the theoretician can modify and evaluate more conceptually–based models. In some cases, the lack of ‘data’ is more accurately represented as a lack of robust estimates of one or more parameters. It is in this arena that methods developed to analyze multiple encounter data from individually marked organisms has seen perhaps the greatest advances. These methods have rapidly evolved to facilitate not only estimation of one or more vital rates, critical to population modeling and analysis, but also to allow for direct estimation of both the dynamics of populations (e.g., Pradel, 1996, and factors influencing those dynamics (e.g., Nichols et al., 2000. The interconnections between the various vital rates, their estimation, and incorporation into models, was the general subject of our plenary presentation by Hal Caswell (Caswell & Fujiwara, 2004. Caswell notes that although interest has traditionally

  16. Superconductor Dynamics

    CERN Document Server

    Gömöry, F.

    2014-07-17

    Superconductors used in magnet technology could carry extreme currents because of their ability to keep the magnetic flux motionless. The dynamics of the magnetic flux interaction with superconductors is controlled by this property. The cases of electrical transport in a round wire and the magnetization of wires of various shapes (circular, elliptical, plate) in an external magnetic field are analysed. Resistance to the magnetic field penetration means that the field produced by the superconducting magnet is no longer proportional to the supplied current. It also leads to a dissipation of electromagnetic energy. In conductors with unequal transverse dimensions, such as flat cables, the orientation with respect to the magnetic field plays an essential role. A reduction of magnetization currents can be achieved by splitting the core of a superconducting wire into fine filaments; however, new kinds of electrical currents that couple the filaments consequently appear. Basic formulas allowing qualitative analyses ...

  17. The Dynamics of Share-Price Formation

    NARCIS (Netherlands)

    J. Tinbergen (Jan)

    1939-01-01

    textabstractIn a recent investigation which the author has made for the League of Nations Secretariat, it was found that share prices seem to have exerted a considerable influence on the course of the American cycle beginning in 1924 and having its boom year in 1929. The chief reason for this

  18. Dynamic model reduction using data-driven Loewner-framework applied to thermally morphing structures

    Science.gov (United States)

    Phoenix, Austin A.; Tarazaga, Pablo A.

    2017-05-01

    The work herein proposes the use of the data-driven Loewner-framework for reduced order modeling as applied to dynamic Finite Element Models (FEM) of thermally morphing structures. The Loewner-based modeling approach is computationally efficient and accurately constructs reduced models using analytical output data from a FEM. This paper details the two-step process proposed in the Loewner approach. First, a random vibration FEM simulation is used as the input for the development of a Single Input Single Output (SISO) data-based dynamic Loewner state space model. Second, an SVD-based truncation is used on the Loewner state space model, such that the minimal, dynamically representative, state space model is achieved. For this second part, varying levels of reduction are generated and compared. The work herein can be extended to model generation using experimental measurements by replacing the FEM output data in the first step and following the same procedure. This method will be demonstrated on two thermally morphing structures, a rigidly fixed hexapod in multiple geometric configurations and a low mass anisotropic morphing boom. This paper is working to detail the method and identify the benefits of the reduced model methodology.

  19. Propulsion System Dynamic Modeling for the NASA Supersonic Concept Vehicle: AeroPropulsoServoElasticity

    Science.gov (United States)

    Kopasakis, George; Connolly, Joseph; Seidel, Jonathan

    2014-01-01

    A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural-aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report.propulsion system dynamics, the structural dynamics, and aerodynamics.

  20. Pressão de aplicação com pulverizador de barra e eficiência de bioinseticidas fúngicos comerciais Application pressure in boom sprayer and efficiency of commercial fungal bioinsecticides

    Directory of Open Access Journals (Sweden)

    Cesar de Oliveira Guimarães

    2004-12-01

    Full Text Available Bioinseticidas fúngicos são aplicados com pulverizadores convencionais e algumas características destes equipamentos podem não ser adequadas e afetar a eficiência dos bioinseticidas. O objetivo deste trabalho foi verificar se pressões usuais, em aplicações com o pulverizador de barra, podem afetar a ação inseticida de conídios de Beauveria bassiana e Metarhizium anisopliae, componentes de produtos comerciais brasileiros. Para isso, suspensões aquosas de três bioinseticidas foram submetidas à passagem pelo equipamento em três pressões (20, 40 e 60 lbf pol-2 e avaliadas quanto ao rompimento, à viabilidade e à virulência dos conídios. Avaliou-se a viabilidade em lâminas de microscopia cobertas com meio de cultura, após incubação a 26±0,5ºC e fotoperíodo de 12 horas. A concentração foi determinada por meio de contagens em câmara de Neubauer e a virulência foi avaliada para lagartas de Diatraea saccharalis. Não foram encontradas, nos três produtos, influências significativas em nenhum dos parâmetros. Nas pressões avaliadas, a aplicação com o pulverizador de barra não reduz a viabilidade e nem a virulência dos conídios dos bioinseticidas testados, tampouco provoca destruição dos conídios.Fungal biopesticides are applied with conventional sprayers and this equipment may be inappropriate, and therefore affect field control efficacy of biopesticides. The objective of this research was to find out if the usual pressures used in the boom sprayers can affect the conidia pesticide activity of the Brazilian commercial entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae. Water fungi suspensions were passed through the equipment under three pressures (20, 40 and 60 psi and evaluated for viability, virulence and conidia disruption. The viability was evaluated in slides covered by culture media after incubation at 26±0.5ºC and 12 hours photophase. The concentration was determined through Neubauer