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Sample records for centauri small-scale structures

  1. Small scale structure on cosmic strings

    International Nuclear Information System (INIS)

    I discuss our current understanding of cosmic string evolution, and focus on the question of small scale structure on strings, where most of the disagreements lie. I present a physical picture designed to put the role of the small scale structure into more intuitive terms. In this picture one can see how the small scale structure can feed back in a major way on the overall scaling solution. I also argue that it is easy for small scale numerical errors to feed back in just such a way. The intuitive discussion presented here may form the basis for an analytic treatment of the small structure, which I argue in any case would be extremely valuable in filling the gaps in our resent understanding of cosmic string evolution. 24 refs., 8 figs

  2. Can small scale structure ever affect cosmological dynamics?

    CERN Document Server

    Adamek, Julian; Durrer, Ruth; Kunz, Martin

    2014-01-01

    The large-scale homogeneity and isotropy of the universe is generally thought to imply a well defined background cosmological model. It may not. Smoothing over structure adds in an extra contribution, transferring power from small scales up to large. Second-order perturbation theory implies that the effect is small, but suggests that formally the perturbation series may not converge. The amplitude of the effect is actually determined by the ratio of the Hubble scales at matter-radiation equality and today - which are entirely unrelated. This implies that a universe with significantly lower temperature today could have significant backreaction from more power on small scales, and so provides the ideal testing ground for understanding backreaction. We investigate this using two different N-body numerical simulations - a 3D Newtonian and a 1D simulation which includes all relevant relativistic effects. We show that while perturbation theory predicts an increasing backreaction as more initial small-scale power is...

  3. Abelian Higgs Cosmic Strings: Small Scale Structure and Loops

    CERN Document Server

    Hindmarsh, Mark; Bevis, Neil

    2008-01-01

    Classical lattice simulations of the Abelian Higgs model are used to investigate small scale structure and loop distributions in cosmic string networks. Use of the field theory ensures that the small-scale physics is captured correctly. The results confirm analytic predictions of Polchinski & Rocha [1] for the two-point correlation function of the string tangent vector, with a power law from length scales of order the string core width up to horizon scale with evidence to suggest that the small scale structure builds up from small scales. An analysis of the size distribution of string loops gives a very low number density, of order 1 per horizon volume, in contrast with Nambu-Goto simulations. Further, our loop distribution function does not support the detailed analytic predictions for loop production derived by Dubath et al. [2]. Better agreement to our data is found with a model based on loop fragmentation [3], coupled with a constant rate of energy loss into massive radiation. Our results show a stron...

  4. The small-scale structure of quantum spacetime

    CERN Document Server

    Burton, Christopher D

    2012-01-01

    Planck-scale quantum spacetime undergoes probabilistic local curvature fluctuations whose distributions cannot explicitly depend on position otherwise vacuum's small-scale quantum structure would fail to be statistically homogeneous. Since the collection of fluctuations is a many-body system, the natural explanation for their position-independent statistics is that they are in equilibrium with each other and distributed at maximum entropy. Consequently, their probability distributions obey the laws of statistical physics which enforces small-scale smoothness, prevents the homogeneity-violating diffusion found in any free quantum system, and maintains decoherence. Their entropy, calculated using the explicitly-constructed phase space of the Riemann whose statistics are derived using a background-independent graviton exchange ensemble, is proportional to the Einstein-Hilbert action evaluated on the macroscopic expected geometry and includes a small, positive cosmological constant. Entropy maximization yields qu...

  5. Abelian Higgs cosmic strings: Small-scale structure and loops

    International Nuclear Information System (INIS)

    Classical lattice simulations of the Abelian Higgs model are used to investigate small-scale structure and loop distributions in cosmic string networks. Use of the field theory ensures that the small-scale physics is captured correctly. The results confirm analytic predictions of Polchinski and Rocha 29 for the two-point correlation function of the string tangent vector, with a power law from length scales of order the string core width up to horizon scale. An analysis of the size distribution of string loops gives a very low number density, of order 1 per horizon volume, in contrast with Nambu-Goto simulations. Further, our loop distribution function does not support the detailed analytic predictions for loop production derived by Dubath et al. 30. Better agreement to our data is found with a model based on loop fragmentation 32, coupled with a constant rate of energy loss into massive radiation. Our results show a strong energy-loss mechanism, which allows the string network to scale without gravitational radiation, but which is not due to the production of string width loops. From evidence of small-scale structure we argue a partial explanation for the scale separation problem of how energy in the very low frequency modes of the string network is transformed into the very high frequency modes of gauge and Higgs radiation. We propose a picture of string network evolution, which reconciles the apparent differences between Nambu-Goto and field theory simulations.

  6. Extreme events and small-scale structure in computational turbulence

    Science.gov (United States)

    Zhai, X. M.; Yeung, P. K.; Sreenivasan, K. R.

    2015-11-01

    Detailed analyses have been made of data from a direct numerical simulation of turbulence on a periodic domain with 81923 grid points designed to improve our understanding of small-scale structure and intermittency. At the Reynolds number of this simulation (1300 based on the Taylor scale) extreme events of dissipation and enstrophy as large as 105 times the mean value are observed. These events are shown to possess a form that is different from similar events at low Reynolds numbers. Extreme vorticity appears to be ``chunky'' in character, in contrast to elongated vortex tubes at moderately large amplitudes commonly reported in the literature. We track the temporal evolution of these extreme events and find that they are generally short-lived, which suggests frequent sampling on-the-fly is useful. Extreme magnitudes of energy dissipation rate and enstrophy are essentially coincident in space and remain so during their evolution. Numerical tests show sensitivity to small-scale resolution and sampling but not machine precision. The connections expected between indicators of fine-scale intermittency such as acceleration statistics and the anomalous scaling of high-order velocity structure functions are also investigated. Supported by NSF Grant ACI-1036170 (Track 1 Petascale Resource Allocations Program).

  7. Scaling and small-scale structure in cosmic string networks

    International Nuclear Information System (INIS)

    We examine the scaling properties of an evolving network of strings in Minkowski spacetime and study the evolution of length scales in terms of a three-scale model proposed by Austin, Copeland, and Kibble (ACK). We find good qualitative and some quantitative agreement between the model and our simulations. We also investigate small-scale structure by altering the minimum allowed size for loop production Ec. Certain quantities depend significantly on this parameter: for example, the scaling density can vary by a factor of 2 or more with increasing Ec. Small-scale structure as defined by ACK disappears if no restrictions are placed on loop production, and the fractal dimension of the string changes smoothly from 2 to 1 as the resolution scale is decreased. Loops are nearly all produced at the lattice cutoff. We suggest that the lattice cutoff should be interpreted as corresponding to the string width, and that in a real network loops are actually produced with this size. This leads to a radically different string scenario, with particle production rather than gravitational radiation being the dominant mode of energy dissipation. At the very least, a better understanding of the discretization effects in all simulations of cosmic strings is called for. copyright 1997 The American Physical Society

  8. Absence of small-scale structure in homogeneous superfluid turbulence

    International Nuclear Information System (INIS)

    By contrast with classical turbulence, which is driven by large-scale shear instabilities, superfluid turbulence is driven homogeneously by the mutual friction between the normal fluid and the superfluid. We suggest that this difference implies that there is no equivalent to a Kolmogorov energy cascade in turbulent superfluid flows. We then compare a recent numerical simulation of superfluid turbulence by Schwartz [Phys. Rev. B 31, 5782 (1985)] with a recent simulation of singular vortex stretching in classical fluids by Siggia and Pumir. This comparison suggests that the rigidity of the quantum-mechanical vortex core inhibits any generation of small-scale structure in the superfluid case. Superfluid turbulence is essentially a two-length-scale phenomenon, where the scales are the average intervortex distance and the vortex-core diameter

  9. Small-Scale Fabrication of Biomimetic Structures for Periodontal Regeneration.

    Science.gov (United States)

    Green, David W; Lee, Jung-Seok; Jung, Han-Sung

    2016-01-01

    The periodontium is the supporting tissues for the tooth organ and is vulnerable to destruction, arising from overpopulating pathogenic bacteria and spirochaetes. The presence of microbes together with host responses can destroy large parts of the periodontium sometimes leading tooth loss. Permanent tissue replacements are made possible with tissue engineering techniques. However, existing periodontal biomaterials cannot promote proper tissue architectures, necessary tissue volumes within the periodontal pocket and a "water-tight" barrier, to become clinically acceptable. New kinds of small-scale engineered biomaterials, with increasing biological complexity are needed to guide proper biomimetic regeneration of periodontal tissues. So the ability to make compound structures with small modules, filled with tissue components, is a promising design strategy for simulating the anatomical complexity of the periodotium attachment complexes along the tooth root and the abutment with the tooth collar. Anatomical structures such as, intima, adventitia, and special compartments such as the epithelial cell rests of Malassez or a stellate reticulum niche need to be engineered from the start of regeneration to produce proper periodontium replacement. It is our contention that the positioning of tissue components at the origin is also necessary to promote self-organizing cell-cell connections, cell-matrix connections. This leads to accelerated, synchronized and well-formed tissue architectures and anatomies. This strategy is a highly effective preparation for tackling periodontitis, periodontium tissue resorption, and to ultimately prevent tooth loss. Furthermore, such biomimetic tissue replacements will tackle problems associated with dental implant support and perimimplantitis. PMID:26903872

  10. Small-Scale Fabrication of Biomimetic Structures for Periodontal Regeneration

    Directory of Open Access Journals (Sweden)

    David William Green

    2016-02-01

    Full Text Available The periodontium is the supporting tissues for the tooth organ and is vulnerable to destruction, arising from overpopulating pathogenic bacteria and spirochaetes. The presence of microbes together with host responses can destroy large parts of the periodontium sometimes leading tooth loss. Permanent tissue replacements are made possible with tissue engineering techniques. However, existing periodontal biomaterials cannot promote proper tissue architectures, necessary tissue volumes within the periodontal pocket and a water-tight barrier, to become clinically acceptable. New kinds of small-scale engineered biomaterials, with increasing biological complexity are needed to guide proper biomimetic regeneration of periodontal tissues. So the ability to make compound structures with small modules, filled with tissue components, is a promising design strategy for simulating the anatomical complexity of the periodotium attachement complexes along the tooth root and the abutment with the tooth collar. Anatomical structures such as, intima, adventitia and special compartments such as the epithelial cell rests of Malassez or a stellate reticulum niche need to be engineered from the start of regeneration to produce proper periodontium replacement.. It is our contention that the positioning of tissue components at the origin is also necessary to promote self-organising cell-cell connections, cell-matrix connections. This leads to accelerated, synchronized and well-formed tissue architectures and anatomies. This strategy is a highly effective preparation for tackling periodontitis, periodontium tissue resorption and to ultimately prevent tooth loss. Furthermore, such biomimetic tissue replacements will tackle problems associated with dental implant support and perimimplantitis.

  11. Detecting small scale CO2 emission structures using OCO-2

    Science.gov (United States)

    Schwandner, Florian M.; Eldering, Annmarie; Verhulst, Kristal R.; Miller, Charles E.; Nguyen, Hai M.; Oda, Tomohiro; O'Dell, Christopher; Rao, Preeti; Kahn, Brian; Crisp, David; Gunson, Michael R.; Sanchez, Robert M.; Ashok, Manasa; Pieri, David; Linick, Justin P.; Yuen, Karen

    2016-04-01

    Localized carbon dioxide (CO2) emission structures cover spatial domains of less than 50 km diameter and include cities and transportation networks, as well as fossil fuel production, upgrading and distribution infra-structure. Anthropogenic sources increasingly upset the natural balance between natural carbon sources and sinks. Mitigation of resulting climate change impacts requires management of emissions, and emissions management requires monitoring, reporting and verification. Space-borne measurements provide a unique opportunity to detect, quantify, and analyze small scale and point source emissions on a global scale. NASA's first satellite dedicated to atmospheric CO2 observation, the July 2014 launched Orbiting Carbon Observatory (OCO-2), now leads the afternoon constellation of satellites (A-Train). Its continuous swath of 2 to 10 km in width and eight footprints across can slice through coincident emission plumes and may provide momentary cross sections. First OCO-2 results demonstrate that we can detect localized source signals in the form of urban total column averaged CO2 enhancements of ~2 ppm against suburban and rural backgrounds. OCO-2's multi-sounding swath observing geometry reveals intra-urban spatial structures reflected in XCO2 data, previously unobserved from space. The transition from single-shot GOSAT soundings detecting urban/rural differences (Kort et al., 2012) to hundreds of soundings per OCO-2 swath opens up the path to future capabilities enabling urban tomography of greenhouse gases. For singular point sources like coal fired power plants, we have developed proxy detections of plumes using bands of imaging spectrometers with sensitivity to SO2 in the thermal infrared (ASTER). This approach provides a means to automate plume detection with subsequent matching and mining of OCO-2 data for enhanced detection efficiency and validation. © California Institute of Technology

  12. Causes and Effects of Small-Scale Spatial Structure in Plant Populations

    OpenAIRE

    Law, R; Purves, D. W.; Murrell, D. J.; Dieckmann, U.

    2002-01-01

    Small-scale spatial structure is important in plant ecology. Plants interact primarily with their immediate neighbors and the view of the community as seen by an individual plant can be quite different from large-scale spatial average. We describe a spatial statistic that captures the plant's-eye view and use it to illustrate the strong spatial structure present in a grassland community. Many processes affect small-scale spatial structure, including intraspecific competition, dispersal of pro...

  13. Small scale structures in coupled scalar field dark matter

    Directory of Open Access Journals (Sweden)

    J. Beyer

    2014-11-01

    Full Text Available We investigate structure formation for ultra-light scalar field dark matter coupled to quintessence, in particular the cosmon–bolon system. The linear power spectrum is computed by a numerical solution of the coupled field equations. We infer the substructure abundance within a Milky Way-like halo. Estimates of dark halo abundances from recent galaxy surveys imply a lower bound on the bolon mass of about 9×10−22 eV. This seems to exclude a possible detection of scalar field dark matter through time variation in pulsar timing signals in the near future.

  14. Small-Scale Interstellar Na I Structure Toward M92

    CERN Document Server

    Andrews, S M; Lauroesch, J T; Andrews, Sean M.; Meyer, David M.

    2001-01-01

    We have used integral field echelle spectroscopy with the DensePak fiber-optic array on the KPNO WIYN telescope to observe the central 27" x 43" of the globular cluster M92 in the Na I D wavelength region at a spatial resolution of 4". Two interstellar Na I absorption components are evident in the spectra at LSR velocities of 0 km/s (Cloud 1) and -19 km/s (Cloud 2). Substantial strength variations in both components are apparent down to scales limited by the fiber-to-fiber separations. The derived Na I column densities differ by a factor of 4 across the Cloud 1 absorption map and by a factor of 7 across the Cloud 2 map. Using distance upper limits of 400 and 800 pc for Cloud 1 and Cloud 2, respectively, the absorption maps indicate structure in the ISM down to scales of 1600 and 3200 AU. The fiber-to-fiber Na I column density differences toward M92 are comparable to those found in a similar study of the ISM toward the globular cluster M15. Overall, the structures in the interstellar components toward M92 have...

  15. Small-scale structure of interstellar H I clouds

    International Nuclear Information System (INIS)

    The VLA has been used to synthesize the spatial distribution of 21-cm wavelength H I absorption from some 15 galactic clouds occulting 3C 111, 3C 161, and 3C 348. The angular resolution of the observations is between 3.5 and 4.4 arcsec, and the background continua extend irregularly over regions of angular size 1 to 3 arcmin. On scales of 1 arcmin, it is found that substantial but smooth variations in channel and line properties are the norm, rather than the exception. The observations suggest that the internal structure of H I (or diffuse) clouds is ordered, in the sense that any underlying chaotic behavior occurs on scales much smaller than the resolution, but still highly nonuniform. 27 references

  16. Modelling of Dust Extinction through Dark Clouds: Small Scale Structure

    Science.gov (United States)

    Clemens, D.; Lada, C.

    1993-12-01

    In order to understand some curious effects discovered in analyzing our deep JHK near-infrared survey of the background stars probing the IC 5146 dark cloud complex (Lada, Lada, Clemens, & Bally 1993), we have constructed a simple model of the dust extinction through a molecular cloud. The effect noticed involved a correlation between the dispersion of the E(H-K) based estimate of A_V, when the stellar estimates of E(H-K) were binned into arcmin sized bins, with the mean A_V computed for those bins. The sense of the correlation is that the dispersion of the extinction rises with the extinction in a nearly linear fashion. Further, the dispersion of the dispersion also rises with extinction. Our model was constructed to try to understand the origin of this unexpected behavior. The model consists of a Poisson generator to populate a bin with stars and various extinction generating functions to add extinction to each star. Additionally, measurement noise and varying amounts of foreground star contamination are added to simulate the actual observations. Remarkably, this simple model is able to rule out several cloud structure models, including uniform extinction across an arcmin sized bin and the case of dense clumplets (rocks) embedded in a low extinction medium. We show that a power law parameterization of the extinction variation with position across a bin is able to fully reproduce the observations for a fairly robust set of power law indices. We also show that foreground star contamination plus any simple extinction model cannot reproduce the observations, while foreground star contamination does not appreciably affect the power law extinction model for foreground stellar fractions less than 30 - 50% of the total stellar content.

  17. Fabrication of small-scale structures with non-planar features

    Science.gov (United States)

    Burckel, David B.; Ten Eyck, Gregory A.

    2015-11-19

    The fabrication of small-scale structures is disclosed. A unit-cell of a small-scale structure with non-planar features is fabricated by forming a membrane on a suitable material. A pattern is formed in the membrane and a portion of the substrate underneath the membrane is removed to form a cavity. Resonators are then directionally deposited on the wall or sides of the cavity. The cavity may be rotated during deposition to form closed-loop resonators. The resonators may be non-planar. The unit-cells can be formed in a layer that includes an array of unit-cells.

  18. Low-force magneto-rheological damper design for small-scale structural control experimentation

    Science.gov (United States)

    Winter, Benjamin D.; Velazquez, Antonio; Swartz, R. Andrew

    2015-03-01

    Experimental validation of novel structural control algorithms is a vital step in both developing and building acceptance for this technology. Small-scale experimental test-beds fulfill an important role in the validation of multiple-degree-offreedom (MDOF) and distributed semi-active control systems, allowing researchers to test the control algorithms, communication topologies, and timing-critical aspects of structural control systems that do not require full-scale specimens. In addition, small-scale building specimens can be useful in combined structural health monitoring (SHM) and LQG control studies, diminishing safety concerns during experiments by using benchtop-scale rather than largescale specimens. Development of such small-scale test-beds is hampered by difficulties in actuator construction. In order to be a useful analog to full-scale structures, actuators for small-scale test-beds should exhibit similar features and limitations as their full-scale counterparts. In particular, semi-active devices, such as magneto-rheological (MR) fluid dampers, with limited authority (versus active mass dampers) and nonlinear behavior are difficult to mimic over small force scales due to issues related to fluid containment and friction. In this study, a novel extraction-type small-force (0- 10 N) MR-fluid damper which exhibits nonlinear hysteresis similar to a full-scale, MR-device is proposed. This actuator is a key development to enable the function of a small-scale structural control test-bed intended for wireless control validation studies. Experimental validation of this prototype is conducted using a 3-story scale structure subjected to simulated single-axis seismic excitation. The actuator affects the structural response commanded by a control computer that executes an LQG state feedback control law and a modified Bouc-Wen lookup table that was previously developed for full-scale MR-applications. In addition, damper dynamic limitations are characterized and

  19. Small-scale structure formation properties of chilled sterile neutrinos as dark matter

    CERN Document Server

    Petraki, Kalliopi

    2008-01-01

    We calculate the free-streaming length and the phase space density of dark-matter sterile neutrinos produced from decays of a gauge singlet in the Higgs sector. These quantities, which depend on the dark matter production mechanism, are relevant to the study of small-scale structure formation and may be used to constrain or rule out dark matter candidates.

  20. First Structure Formation A Simulation of Small Scale Structure at High Redshift

    CERN Document Server

    Jang-Condell, H; Jang-Condell, Hannah; Hernquist, Lars

    2000-01-01

    We describe the results of a simulation of collisionless cold dark matter in a LambdaCDM universe to examine the properties of objects collapsing at high redshift (z=10). We analyze the halos that form at these early times in this simulation and find that the results are similar to those of simulations of large scale structure formation at low redshift. In particular, we consider halo properties such as the mass function, density profile, halo shape, spin parameter, and angular momentum alignment with the minor axis. By understanding the properties of small scale structure formation at high redshift, we can better understand the nature of the first structures in the universe, such as Population III stars.

  1. Solving the small-scale structure puzzles with dissipative dark matter

    CERN Document Server

    Foot, Robert

    2016-01-01

    Small-scale structure is studied in the context of dissipative dark matter, arising for instance in models with a hidden unbroken Abelian sector, so that dark matter couples to a massless dark photon. The dark sector interacts with ordinary matter via gravity and photon-dark photon kinetic mixing. Mirror dark matter is a theoretically constrained special case where all parameters are fixed except for the kinetic mixing strength, $\\epsilon$. In these models, the dark matter halo around spiral and irregular galaxies takes the form of a dissipative plasma which evolves in response to various heating and cooling processes. It has been argued previously that such dynamics can account for the inferred cored density profiles of galaxies and other related structural features. Here we focus on the apparent deficit of nearby small galaxies ("missing satellite problem"), which these dissipative models have the potential to address through small-scale power suppression by acoustic and diffusion damping. Using a variant o...

  2. Small-scale structure formation properties of chilled sterile neutrinos as dark matter

    OpenAIRE

    Petraki, Kalliopi

    2008-01-01

    We calculate the free-streaming length and the phase space density of dark-matter sterile neutrinos produced from decays, at the electroweak scale, of a gauge singlet in the Higgs sector. These quantities, which depend on the dark-matter production mechanism, are relevant to the study of small-scale structure formation and may be used to constrain or rule out dark-matter candidates.

  3. High-temperature Elastic Structural Analysis on a Small-Scale PHE prototype

    International Nuclear Information System (INIS)

    Hydrogen is considered a promising future energy solution because it is clean, abundant, and storable, and has high-energy density. One of the major challenges in establishing a hydrogen economy is how to produce massive quantities of hydrogen in a clean, safe, and economical way. Among the various hydrogen production methods, nuclear hydrogen production is garnering worldwide attention since it can produce hydrogen, a promising energy carrier, without an environmental burden. The PHE (Process Heat Exchanger) is a component that utilizes the nuclear heat from the nuclear reactor to provide hydrogen. A PHE is used in several processes such as nuclear steam reforming, nuclear methanol, nuclear steel, nuclear oil refinery, and nuclear steam. The PHE of the SO3 decomposer, which generates the process gas such as H2O, O2, SO2, and SO3 at a very high temperature, is a key component in the nuclear hydrogen program in Korea. Recently, KAERI (Korea Atomic Energy Research Institute) established a small-scale gas loop for the performance test of VHTR components and manufactured a small-scale PHE prototype made of Hastelloy-X. A performance test on the PHE prototype is under way in the small-scale gas loop at KAERI. In this study, in an effort to evaluate the high-temperature structural integrity of the PHE prototype under the test condition of the gas loop, a high-temperature elastic structural analysis was performed

  4. High-Temperature Structural Analysis of a Small-Scale PHE Prototype under the Test Condition of a Small-Scale Gas Loop

    International Nuclear Information System (INIS)

    A process heat exchanger (PHE) is a key component for transferring the high-temperature heat generated from a very high-temperature reactor (VHTR) to a chemical reaction for the massive production of hydrogen. The Korea Atomic Energy Research Institute has designed and assembled a small-scale nitrogen gas loop for a performance test on VHTR components and has manufactured a small-scale PHE prototype made of Hastelloy-X alloy. A performance test on the PHE prototype is underway in the gas loop, where different kinds of pipelines connecting to the PHE prototype are tested for reducing the thermal stress under the expansion of the PHE prototype. In this study, to evaluate the high-temperature structural integrity of the PHE prototype under the test condition of the gas loop, a realistic and effective boundary condition imposing the stiffness of the pipelines connected to the PHE prototype was suggested. An equivalent spring stiffness to reduce the thermal stress under the expansion of the PHE prototype was computed from the bending deformation and expansion of the pipelines connected to the PHE. A structural analysis on the PHE prototype was also carried out by imposing the suggested boundary condition. As a result of the analysis, the structural integrity of the PHE prototype seems to be maintained under the test condition of the gas loop.

  5. Small-scale structure in the Rosette molecular cloud revealed by Herschel

    OpenAIRE

    Di Francesco, J.; Sadavoy, S.; Motte, F; Schneider, N.; Hennemann, M.; Csengeri, T.; Bontemps, S.; Z. Balog; Zavagno, A.; André, Ph.; Saraceno, P.; Griffin, M; Men'shchikov, A.; Abergel, A; Baluteau, J. -P.

    2010-01-01

    We present a preliminary analysis of the small-scale structure found in new 70-520 μm continuum maps of the Rosette molecular cloud (RMC), obtained with the SPIRE and PACS instruments of the Herschel Space Observatory. We find 473 clumps within the RMC using a new structure identification algorithm, with sizes up to ~1.0 pc in diameter. A comparison with recent Spitzer maps reveals that 371 clumps are "starless" (without an associated young stellar object), while 102 are "protostellar". Using...

  6. Quiet Sun coronal heating analyzing large scale magnetic structures driven by different small-scale uniform sources

    CERN Document Server

    Podladchikova, O; Krasnoselskikh, V V; Lefebvre, B

    2002-01-01

    Recent measurements of quiet Sun heating events by Krucker and Benz (1998) give strong support to Parker's (1988) hypothesis that small scale dissipative events make the main contribution to the quiet heating. Moreover, combining their observations with the analysis by Priest et al. (2000), it can be concluded that the sources driving these dissipative events are also small scale sources, typically of the order of (or smaller than) 2000 km and the resolution of modern instruments. Thus arises the question of how these small scale events participate into the larger scale observable phenomena, and how the information about small scales can be extracted from observations. This problem is treated in the framework of a simple phenomenological model introduced in Krasnoselskikh et al. (2001), which allows to switch between various small scale sources and dissipative processes. The large scale structure of the magnetic field is studied by means of Singular Value Decomposition (SVD) and a derived entropy, techniques ...

  7. Seeking Observable Imprints of Small-Scale Structure on the Properties of Dark Matter Haloes

    CERN Document Server

    Power, Chris

    2013-01-01

    The characteristic prediction of the Cold Dark Matter (CDM) model of cosmological structure formation is that the Universe should contain a wealth of small-scale structure -- low-mass dark matter haloes and subhaloes. However, galaxy formation is inefficient in their shallow potential wells and so we expect these low-mass haloes and subhaloes to be dark. Can we tell the difference between a Universe in which low-mass haloes are present but dark and one in which they never formed, thereby providing a robust test of the CDM model? We address this question using cosmological simulations to examine how properties of low-mass haloes that are potentially accessible to observation, such as their spatial clustering, rate of accretions and mergers onto massive galaxies and the angular momentum content of massive galaxies, differ between a LCDM model and dark matter models in which low-mass halo formation is suppressed. Adopting an effective cut-off mass scale M_cut below which small-scale power is suppressed in the in...

  8. Vegetation structure and small-scale pattern in Miombo Woodland, Marondera, Zimbabwe

    Directory of Open Access Journals (Sweden)

    B. M. Campbell

    1995-12-01

    Full Text Available The aim ol this paper is to describe woodland structure and small-scale patterning of woody plants at a miombo site, and to relate these to past disturbance and soil properties. Brachystegia spiciformis Benth. and Julbemardia globiflora (Benth. Troupin were the most frequent woody plants at the five hectare site, with size-class distributions which were markedly skewed towards the smaller size classes. The vegetation structure at the site and the increase in basal area over the past thirty years point to considerable disturbance prior to the present protected status. Six woodland subtypes were identified, grouped into two structural types: open and closed woodland. The distribution of woodland subtypes related closely to certain soil properties. It was hypothesized that the distribution of open and closed woodland is stable and a positive feedback mechanism by which this occurs is postulated.

  9. Challenges During Microstructural Analysis and Mechanical Testing of Small-Scale Pseudoelastic NiTi Structures

    Science.gov (United States)

    Hahn, S.; Wagner, M. F.-X.

    2016-06-01

    Most investigations on NiTi-based shape memory alloys involve large-scale bulk material; knowledge about the martensitic transformation in small-scale NiTi structures is still limited. In this paper, we study the microstructures of thin NiTi layers and their mechanical properties, and we discuss typical challenges that arise when experiments are performed on small samples. A physical vapor deposition (PVD) process was used to deposit thin NiTi wires with a cross section of 15 × 15 μm2 and dogbone-shaped samples 5 × 500 μm2. Microstructural properties were characterized by X-ray diffraction, electron backscatter diffraction, and scanning electron microscopy. Moreover, tensile tests were performed using optical strain measurements in order to observe martensite band formation during cyclic loading. The surfaces of the crystalline wires reflect the columnar growth of NiTi during deposition. The wires exhibit pseudoelastic material behavior during tensile testing. Fracture typically occurs along the columns because the column growth direction is perpendicular to the straining direction. Electropolishing removes these local stress raisers and hence increases fracture strains. Our results demonstrate that the pseudoelastic properties of the PVD-processed materials agree well with those of conventional NiTi, and that they provide new opportunities to study the fundamentals of martensitic transformation in small-scale model systems.

  10. Small-scale structure in the Rosette molecular cloud revealed by Herschel

    CERN Document Server

    Di Francesco, J; Motte, F; Schneider, N; Hennemann, M; Bontemps, S; Csengeri, T; Balog, Z; Zavagno, A; Andre, Ph; Saraceno, P; Griffin, M; Men'shchikov, A; Abergel, A; Baluteau, J -P; Bernard, J -Ph; Cox, P; Deharveng, L; Didelon, P; di Giorgio, A -M; Hargrave, P; Huang, M; Kirk, J; Leeks, S; Li, J Z; Marston, A; Martin, P; Minier, V; Molinari, S; Olofsson, G; Persi, P; Pezzuto, S; Russeil, D; Sauvage, M; Sibthorpe, B; Spinoglio, L; Testi, L; Teyssier, D; Vavrek, R; Ward-Thompson, D; White, G; Wilson, C; Woodcraft, A

    2010-01-01

    We present a preliminary analysis of the small-scale structure found in new 70-520 micron continuum maps of the Rosette molecular cloud (RMC), obtained with the SPIRE and PACS instruments of the Herschel Space Observatory. We find 473 clumps within the RMC using a new structure identification algorithm, with sizes up to ~1.0 pc in diameter. A comparison with recent Spitzer maps reveals that 371 clumps are "starless" (without an associated young stellar object), while 102 are "protostellar." Using the respective values of dust temperature, we determine the clumps have masses (M_C) over the range -0.75 <= log (M_C/M_sun) <= 2.50. Linear fits to the high-mass tails of the resulting clump mass spectra (CMS) have slopes that are consistent with those found for high-mass clumps identified in CO emission by other groups.

  11. Small-scale polymer structures enabled by thiol-ene copolymer systems

    Science.gov (United States)

    Kasprzak, Scott Edward

    2009-12-01

    The research described herein is aimed at exploring the thermomechanical properties of thiol-ene polymers in bulk form, investigating the ability of thiol-ene polymers to behave desirably as photolithographic media, and providing the first characterization of the mechanical properties of two-photon stereolithography-produced polymer structures. The thiol-ene polymerization reaction itself is well-characterized and described in the literature, but the thermomechanical properties of thiol-ene and thiol-ene/acrylate polymers still require more rigorous study. Understanding the behavior of thiol-ene networks is a crucial step towards their expanded use in bulk form, and particularly in specialized applications such as shape memory devices. Additionally, the thiol-ene polymerization reaction mechanism exhibits unique properties which make these polymers well suited to photolithography, overcoming the typical dichotomy of current materials which either exhibit excellent photolithographic behavior or have controllable properties. Finally, before two-photon stereolithography can create mechanisms and devices which can serve any mechanically functional role, the mechanical properties of the polymers they produce must be quantitatively characterized, which is complicated by the extremely small scale at which these structures are produced. As such, mechanical characterization to date has been strictly qualitative. Fourier transfer infrared spectroscopy revealed functional group conversion information and sol-fraction testing revealed the presence of unconverted monomer and impurities, while dynamic mechanical analysis (DMA) and tensile testing revealed the thermomechanical responses of the systems. Nanoindentation was employed to characterize the mechanical properties of micrometer-scale polymer structures produced by two-photon stereolithography. Optical and electron microscopy were exploited to provide both quantitative and qualitative evaluations of thiol-ene/acrylate and

  12. Thermal evolution and small scale structure of Sommerfeld enhanced dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Aarssen, Laura Gusta van den

    2013-04-15

    Although the existence of Dark Matter (DM) has been confirmed by many independent observations on various scales, its nature still remains a mystery. Leading candidates for the cold, non-baryonic DM are Weakly Interacting Massive Particles (WIMPs), that are well motivated from particle physics and naturally explain the observed relic density by their thermal production mechanism. In this thesis we focus on a particular class of WIMP models in which the Sommerfeld effect has to be taken into account. This is a quantum mechanical phenomenon that can significantly enhance the annihilation cross section in the non-relativistic limit. To describe the non-perturbative effect, we use a non-relativistic effective field theory derived from the full quantum field theory. We include a detailed discussion of the calculation for the righthanded sneutrino, which is the superpartner of the neutrino and a viable DM candidate. The Sommerfeld enhancement can have a profound influence on the thermal evolution of the DM, which can no longer be described by the standard scenario. We introduce a framework to correctly take this effect into account and apply it to a simple leptophilic DM model. A new era of annihilations can decrease the DM density even after usual freeze-out, and in some cases where the Sommerfeld enhancement is especially large, even continue until after matter-radiation equality. The effect on the asymptotic WIMP temperature, which can be directly related to a small scale cutoff in the matter density fluctuations, causes the mass of the smallest gravitationally bound objects to be larger than expected from standard calculations. Furthermore we study the effect of velocity dependent DM self-scattering in relation to the small scale structure formation. Numerical simulations of {Lambda}CDM have shown a remarkable agreement with the large scale structure of the Universe. However, the simulations are in tension with observed abundances, inner densities and velocity

  13. Thermal evolution and small scale structure of Sommerfeld enhanced dark matter

    International Nuclear Information System (INIS)

    Although the existence of Dark Matter (DM) has been confirmed by many independent observations on various scales, its nature still remains a mystery. Leading candidates for the cold, non-baryonic DM are Weakly Interacting Massive Particles (WIMPs), that are well motivated from particle physics and naturally explain the observed relic density by their thermal production mechanism. In this thesis we focus on a particular class of WIMP models in which the Sommerfeld effect has to be taken into account. This is a quantum mechanical phenomenon that can significantly enhance the annihilation cross section in the non-relativistic limit. To describe the non-perturbative effect, we use a non-relativistic effective field theory derived from the full quantum field theory. We include a detailed discussion of the calculation for the righthanded sneutrino, which is the superpartner of the neutrino and a viable DM candidate. The Sommerfeld enhancement can have a profound influence on the thermal evolution of the DM, which can no longer be described by the standard scenario. We introduce a framework to correctly take this effect into account and apply it to a simple leptophilic DM model. A new era of annihilations can decrease the DM density even after usual freeze-out, and in some cases where the Sommerfeld enhancement is especially large, even continue until after matter-radiation equality. The effect on the asymptotic WIMP temperature, which can be directly related to a small scale cutoff in the matter density fluctuations, causes the mass of the smallest gravitationally bound objects to be larger than expected from standard calculations. Furthermore we study the effect of velocity dependent DM self-scattering in relation to the small scale structure formation. Numerical simulations of ΛCDM have shown a remarkable agreement with the large scale structure of the Universe. However, the simulations are in tension with observed abundances, inner densities and velocity profiles of

  14. Small-scale structure and dynamics of the lower solar atmosphere

    CERN Document Server

    Wedemeyer-Böhm, Sven

    2007-01-01

    The chromosphere of the quiet Sun is a highly intermittent and dynamic phenomenon. Three-dimensional radiation (magneto-)hydrodynamic simulations exhibit a mesh-like pattern of hot shock fronts and cool expanding post-shock regions in the sub-canopy part of the inter-network. This domain might be called "fluctosphere". The pattern is produced by propagating shock waves, which are excited at the top of the convection zone and in the photospheric overshoot layer. New high-resolution observations reveal a ubiquitous small-scale pattern of bright structures and dark regions in-between. Although it qualitatively resembles the picture seen in models, more observations - e.g. with the future ALMA - are needed for thorough comparisons with present and future models. Quantitative comparisons demand for synthetic intensity maps and spectra for the three-dimensional (magneto-)hydrodynamic simulations. The necessary radiative transfer calculations, which have to take into account deviations from local thermodynamic equil...

  15. Solving the small-scale structure puzzles with dissipative dark matter

    Science.gov (United States)

    Foot, Robert; Vagnozzi, Sunny

    2016-07-01

    Small-scale structure is studied in the context of dissipative dark matter, arising for instance in models with a hidden unbroken Abelian sector, so that dark matter couples to a massless dark photon. The dark sector interacts with ordinary matter via gravity and photon-dark photon kinetic mixing. Mirror dark matter is a theoretically constrained special case where all parameters are fixed except for the kinetic mixing strength, epsilon. In these models, the dark matter halo around spiral and irregular galaxies takes the form of a dissipative plasma which evolves in response to various heating and cooling processes. It has been argued previously that such dynamics can account for the inferred cored density profiles of galaxies and other related structural features. Here we focus on the apparent deficit of nearby small galaxies (``missing satellite problem"), which these dissipative models have the potential to address through small-scale power suppression by acoustic and diffusion damping. Using a variant of the extended Press-Schechter formalism, we evaluate the halo mass function for the special case of mirror dark matter. Considering a simplified model where Mbaryons propto Mhalo, we relate the halo mass function to more directly observable quantities, and find that for epsilon ≈ 2 × 10‑10 such a simplified description is compatible with the measured galaxy luminosity and velocity functions. On scales Mhalo lesssim 108 Msolar, diffusion damping exponentially suppresses the halo mass function, suggesting a nonprimordial origin for dwarf spheroidal satellite galaxies, which we speculate were formed via a top-down fragmentation process as the result of nonlinear dissipative collapse of larger density perturbations. This could explain the planar orientation of satellite galaxies around Andromeda and the Milky Way.

  16. Evaluation on the High-temperature Structural Integrity of the small-scale PHE prototype

    International Nuclear Information System (INIS)

    Recently, nuclear hydrogen production is garnering worldwide attention since it can produce hydrogen, a promising energy carrier, without an environmental burden. The nuclear hydrogen program in the Republic of Korea (ROK) is strongly considering producing hydrogen by employing a Sulfur-Iodine (SI) water-splitting hydrogen production processes. An intermediate loop that transports the nuclear heat to the hydrogen production process is necessitated for the nuclear hydrogen program as shown in Fig. 1. In the intermediate loop, whereas the HGD (Hot Gas Duct) provide a route of a high temperature gas from the nuclear reactor to the IHX (Intermediate Heat Exchanger), the PHE (Process Heat Exchanger) is a component that utilizes the nuclear heat from the nuclear reactor to provide hydrogen. PHE is used in several processes such as nuclear steam reforming, nuclear methanol, nuclear steel, nuclear oil refinery, and nuclear steam. PHE of the SO3 decomposer which generates processed gas, such as H2O, O2, SO2, and SO3 at very high temperature is a key component in the nuclear hydrogen program in ROK. A performance test on the small-scale PHE prototype made of Hastelloy-X is under way in the small-scale gas loop at KAERI as shown in Fig. 2. In this study, in order to evaluate the high-temperature structural integrity of the PHE prototype under the test condition of the gas loop, structural analysis on the PHE prototype is carried out, considering the stiffness of pipelines connected to the PHE prototype in the gas loop

  17. Ethical Guidelines for Structural Interventions to Small-Scale Historic Stone Masonry Buildings.

    Science.gov (United States)

    Hurol, Yonca; Yüceer, Hülya; Başarır, Hacer

    2015-12-01

    Structural interventions to historic stone masonry buildings require that both structural and heritage values be considered simultaneously. The absence of one of these value systems in implementation can be regarded as an unethical professional action. The research objective of this article is to prepare a guideline for ensuring ethical structural interventions to small-scale stone historic masonry buildings in the conservation areas of Northern Cyprus. The methodology covers an analysis of internationally accepted conservation documents and national laws related to the conservation of historic buildings, an analysis of building codes, especially Turkish building codes, which have been used in Northern Cyprus, and an analysis of the structural interventions introduced to a significant historic building in a semi-intact state in the walled city of Famagusta. This guideline covers issues related to whether buildings are intact or ruined, the presence of earthquake risk, the types of structural decisions in an architectural conservation project, and the values to consider during the decision making phase. PMID:25524322

  18. Backscattering from small-scale breaking wave turbulence structure generated by FLUENT

    International Nuclear Information System (INIS)

    A breaking wave can exert a great influence on the electromagnetic (EM) scattering result from sea surfaces. In this paper, the process of small-scale wave breaking is simulated by the commercial computational fluid dynamics (CFD) software FLUENT, and the backscattering radar cross section (RCS) of the turbulence structure after breaking is calculated with the method of moments. The scattering results can reflect the turbulent intensities of the wave profiles and can indicate high polarization ratios at moderate incident angles, which should be attributed to the incoherent backscatter from surface disturbance of turbulence structure. Compared with the wave profile before breaking, the turbulence structure has no obvious geometrical characteristic of a plunging breaker, and no sea spikes are present at large incident angles either. In summary, the study of EM scattering from turbulence structure can provide a basis to explain the anomalies of EM scattering from sea surfaces and help us understand the scattering mechanism about the breaking wave more completely. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  19. Analysis of small scale turbulent structures and the effect of spatial scales on gas transfer

    Science.gov (United States)

    Schnieders, Jana; Garbe, Christoph

    2014-05-01

    The exchange of gases through the air-sea interface strongly depends on environmental conditions such as wind stress and waves which in turn generate near surface turbulence. Near surface turbulence is a main driver of surface divergence which has been shown to cause highly variable transfer rates on relatively small spatial scales. Due to the cool skin of the ocean, heat can be used as a tracer to detect areas of surface convergence and thus gather information about size and intensity of a turbulent process. We use infrared imagery to visualize near surface aqueous turbulence and determine the impact of turbulent scales on exchange rates. Through the high temporal and spatial resolution of these types of measurements spatial scales as well as surface dynamics can be captured. The surface heat pattern is formed by distinct structures on two scales - small-scale short lived structures termed fish scales and larger scale cold streaks that are consistent with the footprints of Langmuir Circulations. There are two key characteristics of the observed surface heat patterns: 1. The surface heat patterns show characteristic features of scales. 2. The structure of these patterns change with increasing wind stress and surface conditions. In [2] turbulent cell sizes have been shown to systematically decrease with increasing wind speed until a saturation at u* = 0.7 cm/s is reached. Results suggest a saturation in the tangential stress. Similar behaviour has been observed by [1] for gas transfer measurements at higher wind speeds. In this contribution a new model to estimate the heat flux is applied which is based on the measured turbulent cell size und surface velocities. This approach allows the direct comparison of the net effect on heat flux of eddies of different sizes and a comparison to gas transfer measurements. Linking transport models with thermographic measurements, transfer velocities can be computed. In this contribution, we will quantify the effect of small scale

  20. The Small-Scale Structure of the Magellanic Stream as a Foundation for Galaxy Evolution

    Directory of Open Access Journals (Sweden)

    Nigra, L.

    2010-06-01

    Full Text Available The Magellanic Stream (MS is the nearest example of agaseous trail formed by interacting galaxies. While the substantial gas masses in these kinds of circumgalactic structures are postulated to represent important sources of fuel for future star formation, the mechanisms whereby this material might be accreted back into galaxies remain unclear. Recent neutral hydrogen (HI observations have demonstrated that the northern portion of the MS, which probably has been interacting with the Milky Way's hot gaseous halo for close to 1000~Myr, has a larger spatial extent than previously recognized, while also containing significant amounts of small-scale structure. After a brief consideration of the large-scale kinematics of the MS as traced by the recently-discovered extension of the MS, we explore the aging process of the MS gas through the operation of various hydrodynamic instabilities and interstellar turbulence. This in turn leads to consideration of processes whereby MS material survives as cool gas, and yet also evidently fails to form stars.Parallels between the MS and extragalactic tidal features are briefly discussed with an emphasis on steps toward establishing what the MS reveals about the critical role of local processes in determining the evolution of these kinds of systems.

  1. Skewness-induced asymmetric modulation of small-scale turbulence by large-scale structures

    Science.gov (United States)

    Agostini, Lionel; Leschziner, Michael; Gaitonde, Datta

    2016-01-01

    Several recent studies discuss of role of skewness of the turbulent velocity fluctuations in near-wall shear layers, in the context of quantifying the correlation between large-scale motions and amplitude variations of small-scale fluctuations—referred to as "modulation." The present study is based on the premise that the skewness of the small-scale fluctuations should be accounted for explicitly in the process of defining their envelope, which characterizes their amplitude variations. This leads to the notion of two envelopes, one for positive and the other for negative small-scale fluctuations, and hence also to two corresponding correlation coefficients. Justification for this concept is provided first by an examination of a high-frequency synthetic signal subjected to realistic skewness-inducing modulation. A new formalism is provided for deriving the two envelopes, and its fidelity is demonstrated for the synthetic test case. The method is then applied to a channel flow at a friction Reynolds number of 4200, for which direct numerical simulation (DNS) data are available. The large-scale and small-scale fields are separated by the empirical mode decomposition method, and the modulation of the small-scale fluctuations by the large scales is examined. Separate maps of the correlation coefficient and of two-point correlations, the latter linking the large-scale motions and the envelopes of the small-scale motions, are derived for the two envelopes pertaining to positive and negative small-scale fluctuations, and these demonstrate a significant sensitivity to the envelope-definition process, especially close to the wall where the skewness of the small-scale fluctuations is the dominant contributor to the total value.

  2. Alpha centauri unveiling the secrets of our nearest stellar neighbor

    CERN Document Server

    Beech, Martin

    2015-01-01

    As our closest stellar companion and composed of two Sun-like stars and a third small dwarf star, Alpha Centauri is an ideal testing ground of astrophysical models and has played a central role in the history and development of modern astronomy—from the first guesses at stellar distances to understanding how our own star, the Sun, might have evolved. It is also the host of the nearest known exoplanet, an ultra-hot, Earth-like planet recently discovered. Just 4.4 light years away Alpha Centauri is also the most obvious target for humanity’s first directed interstellar space probe. Such a mission could reveal the small-scale structure of a new planetary system and also represent the first step in what must surely be humanity’s greatest future adventure—exploration of the Milky Way Galaxy itself. For all of its closeness, α Centauri continues to tantalize astronomers with many unresolved mysteries, such as how did it form, how many planets does it contain and where are they, and how might we view its ex...

  3. High temperature structural analysis of a small scale PHE prototype -Analysis considering material properties in weld zone-

    International Nuclear Information System (INIS)

    A process heat exchanger (PHE) in a nuclear hydrogen system is a key component for transferring the considerable heat generated in a very high temperature reactor (VHTR) to a chemical reaction that yields a large quantity of hydrogen. A performance test on a small scale PHE prototype made of Hastelloy X is underway in a small scale gas loop at the Korea Atomic Energy Research Institute. Previous research on the high temperature structural analysis of the small scale PHE prototype had been performed using base material properties. In this study, a high temperature structural analysis considering the mechanical properties in the weld zone was performed, and the obtained results were compared with those of the previous research

  4. Space-borne detection of small scale CO2 emission structures with OCO-2

    Science.gov (United States)

    Schwandner, F. M.; Eldering, A.; Verhulst, K. R.; Miller, C. E.; Nguyen, H.; Oda, T.; O'Dell, C.; Rao, P.; Kahn, B. H.; Crisp, D.; Gunson, M. R.; Sanchez, R. M.; Ashok, M.; Birman, L.; Pieri, D. C.; Linick, J. P.; Xing, Z.; Yuen, K.

    2015-12-01

    Localized carbon dioxide (CO2) emission structures covering spatial domains of less than 50km diameter include cities, transportation infrastructure, fossil fuel production, upgrading and consumption sites. Anthropogenic sources upset the natural balance between carbon sources and sinks. Mitigation of resulting climate change impacts requires management of emissions, and emissions management requires monitoring, reporting and verification. Space-borne measurements provide a unique opportunity to detect, quantify, and analyze small scale and point source emissions on a global scale. In 2014, NASA launched its first satellite dedicated to atmospheric CO2 observation, the Orbiting Carbon Observatory (OCO-2). Its observation strategy differs from sparse point-wise measurements from the Japanese Greenhouse gas Observation SATellite (GOSAT) instrument. At the expense of GOSAT's fast time series capability (3-day repeat cycle, vs. 16 for OCO-2), its 8-footprint continuous swath of 2 to 10 km in width can slice through emission plumes and possibly provide momentary cross sections. While GOSAT measured approximately circular ~10.5 km diameter single-shot footprints, OCO-2 can provide hundreds more soundings per area at single kilometer scale footprint resolution. First OCO-2 results demonstrate that we can detect localized source signals in the form of urban XCO2 enhancements of ~2 ppmv against suburban and rural backgrounds. OCO-2's multi-sounding swath observing geometry reveals intra-urban emission spatial structures previously unobserved from space. The transition from single-shot GOSAT soundings detecting urban/rural differences (Kort et al., 2012) to hundreds of soundings per OCO-2 swath opens up the path to future capabilities enabling urban greenhouse gas tomography. © California Institute of Technology

  5. Small scale structure of magnetospheric electron density through on-line tracking of plasma resonances

    International Nuclear Information System (INIS)

    The plasma resonance phenomena observed at fsub(pe), nfsub(ce), and fsub(qn) by the GEOS-1 S-301 relaxation sounder are identified through a pattern recognition software process implemented in a mini-computer which receives on-line the compressed data. First, this processing system distributes in real time fsub(pe) and fsub(ce) measurements to the ground media. Second, it drives and controls automatically the S-301 on-board experiment by sending appropriate telecommands: the tracking of resonances is performed by shortening the frequency sweeps to a narrow range centered on the resonance location. Examples of such tracking sequences are presented, exhibiting sampling rates of the electron density measurements from once every 22s (slowest rate) to once every 86 ms (highest rate available). The results give evidence of the existence of very small scale structures in the magnetospheric density, having characteristic sizes of the order of a few 102m or/and a few 10-1s. The relative amplitude of these density fluctuations is typically 1%. Because of satellite spinning, fixed frequency sounding sequences allow to measure in a few seconds the directivity features of the plasma resonance signals. Examples of directional patterns in the plane perpendicular to the geomagnetic field are presented: the electrostatic nature of the waves received at fsub(pe), nfsub(ce), and fsub(qn) being consistent with these patterns, the corresponding k vector orientations become available. The Bernstein modes properties are used to interpret the nfsub(ce) and fsub(qn) results. (Auth.)

  6. Small-scale transport structures in the Arctic winter 2009/2010

    Directory of Open Access Journals (Sweden)

    C. Kalicinsky

    2013-04-01

    Full Text Available The CRISTA-NF (Cryogenic Infrared Spectrometers and Telescope for the Atmosphere – New Frontiers instrument is an airborne infrared limb sounder operated aboard the Russian research aircraft M55-Geophysica. The instrument successfully participated in a large Arctic aircraft campaign within the RECONCILE (Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions project from January to March 2010 in Kiruna, Sweden. This paper concentrates on the measurements during one flight of the campaign, which took place on 2 March in the vicinity of the polar vortex. We present two-dimensional cross-sections of volume mixing ratios for the trace gases CFC-11, O3, and ClONO2 with an unprecedented vertical resolution of about 500 to 600 m for a large part of the observed altitude range and a dense horizontal sampling along flight direction of ≈ 15 km. The trace gas distributions show several structures like the polar vortex and filaments composed of air masses of different origin. The situation during the analysed flight is simulated by the chemistry and transport model CLaMS (Chemical Lagrangian Model of the Stratosphere and compared with the measurements to assess the performance of the model with respect to advection, mixing, and the chemistry in the polar vortex. These comparisons confirm the capability of CLaMS to reproduce even very small-scale structures in the atmosphere. Based on the good agreement between simulation and observation, we use a model concept utilising artificial tracers to further analyse the CRISTA-NF observations in terms of air mass origin. A characteristic of the Arctic winter 2009/10 was a sudden stratospheric warming in early December that led to a split of the polar vortex. The vortex re-established at the end of December. Our passive tracer simulations suggest that large parts of the re-established vortex consisted to about 45% of high- and

  7. SMALL-SCALE STRUCTURING OF ELLERMAN BOMBS AT THE SOLAR LIMB

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, C. J.; Doyle, J. G. [Armagh Observatory, College Hill, Armagh BT61 9DG (United Kingdom); Scullion, E. M. [Institute of Theoretical Astrophysics, University of Oslo, NO-0371 Oslo (Norway); Freij, N.; Erdélyi, R. [Solar Physics and Space Plasma Research Centre, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

    2015-01-01

    Ellerman bombs (EBs) have been widely studied in recent years due to their dynamic, explosive nature and apparent links to the underlying photospheric magnetic field implying that they may be formed by magnetic reconnection in the photosphere. Despite a plethora of researches discussing the morphologies of EBs, there has been a limited investigation of how these events appear at the limb, specifically, whether they manifest as vertical extensions away from the disk. In this article, we make use of high-resolution, high-cadence observations of an Active Region at the solar limb, collected by the CRisp Imaging SpectroPolarimeter (CRISP) instrument, to identify EBs and infer their physical properties. The upper atmosphere is also probed using the Solar Dynamic Observatory's Atmospheric Imaging Assembly (SDO/AIA). We analyze 22 EB events evident within these data, finding that 20 appear to follow a parabolic path away from the solar surface at an average speed of 9 km s{sup –1}, extending away from their source by 580 km, before retreating back at a similar speed. These results show strong evidence of vertical motions associated with EBs, possibly explaining the dynamical ''flaring'' (changing in area and intensity) observed in on-disk events. Two in-depth case studies are also presented that highlight the unique dynamical nature of EBs within the lower solar atmosphere. The viewing angle of these observations allows for a direct linkage between these EBs and other small-scale events in the Hα line wings, including a potential flux emergence scenario. The findings presented here suggest that EBs could have a wider-reaching influence on the solar atmosphere than previously thought, as we reveal a direct linkage between EBs and an emerging small-scale loop, and other near-by small-scale explosive events. However, as previous research found, these extensions do not appear to impact upon the Hα line core, and are not observed by the SDO/AIA EUV

  8. SMALL-SCALE PRESSURE-BALANCED STRUCTURES DRIVEN BY OBLIQUE SLOW MODE WAVES MEASURED IN THE SOLAR WIND

    Energy Technology Data Exchange (ETDEWEB)

    Yao Shuo [School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing 100083 (China); He, J.-S.; Tu, C.-Y.; Wang, L.-H. [Department of Geophysics, Peking University, Beijing (China); Marsch, E., E-mail: yaoshuo@cugb.edu.cn [Christian Albrechts University at Kiel, Kiel (Germany)

    2013-09-01

    Recently, small-scale pressure-balanced structures (PBSs) were identified in the solar wind, but their formation mechanism remains unclear. This work aims to reveal the dependence of the properties of small-scale PBSs on the background magnetic field (B{sub 0}) direction and thus to corroborate the in situ mechanism that forms them. We analyze the plasma and magnetic field data obtained by WIND in the quiet solar wind at 1 AU. First, we use a developed moving-average method to obtain B{sub 0}(s, t) for every temporal scale (s) at each time moment (t). By wavelet cross-coherence analysis, we obtain the correlation coefficients between the thermal pressure P{sub th} and the magnetic pressure P{sub B}, distributing against the temporal scale and the angle {theta}{sub xB} between B{sub 0}(s, t) and Geocentric Solar Ecliptic coordinates (GSE)-x. We note that the angle coverage of a PBS decreases with shorter temporal scale, but the occurrence of the PBSs is independent of {theta}{sub xB}. Suspecting that the isolated small PBSs are formed by compressive waves in situ, we continue this study by testing the wave modes forming a small-scale PBS with B{sub 0}(s, t) quasi-parallel to GSE-x. As a result, we identify that the cross-helicity and the compressibility attain values for a slow mode from theoretical calculations. The wave vector is derived from minimum variance analysis. Besides, the proton temperatures obey T < T{sub Parallel-To} derived from the velocity distribution functions, excluding a mirror mode, which is the other candidate for the formation of PBSs in situ. Thus, a small-scale PBS is shown to be driven by oblique, slow-mode waves in the solar wind.

  9. SMALL-SCALE PRESSURE-BALANCED STRUCTURES DRIVEN BY OBLIQUE SLOW MODE WAVES MEASURED IN THE SOLAR WIND

    International Nuclear Information System (INIS)

    Recently, small-scale pressure-balanced structures (PBSs) were identified in the solar wind, but their formation mechanism remains unclear. This work aims to reveal the dependence of the properties of small-scale PBSs on the background magnetic field (B0) direction and thus to corroborate the in situ mechanism that forms them. We analyze the plasma and magnetic field data obtained by WIND in the quiet solar wind at 1 AU. First, we use a developed moving-average method to obtain B0(s, t) for every temporal scale (s) at each time moment (t). By wavelet cross-coherence analysis, we obtain the correlation coefficients between the thermal pressure Pth and the magnetic pressure PB, distributing against the temporal scale and the angle θxB between B0(s, t) and Geocentric Solar Ecliptic coordinates (GSE)-x. We note that the angle coverage of a PBS decreases with shorter temporal scale, but the occurrence of the PBSs is independent of θxB. Suspecting that the isolated small PBSs are formed by compressive waves in situ, we continue this study by testing the wave modes forming a small-scale PBS with B0(s, t) quasi-parallel to GSE-x. As a result, we identify that the cross-helicity and the compressibility attain values for a slow mode from theoretical calculations. The wave vector is derived from minimum variance analysis. Besides, the proton temperatures obey T ∥ derived from the velocity distribution functions, excluding a mirror mode, which is the other candidate for the formation of PBSs in situ. Thus, a small-scale PBS is shown to be driven by oblique, slow-mode waves in the solar wind

  10. The magnetic structure of surges in small-scale emerging flux regions

    CERN Document Server

    MacTaggart, David; Haynes, Andrew; Simitev, Radostin; Zuccarello, Francesca

    2015-01-01

    Aims: To investigate the relationship between surges and magnetic reconnection during the emergence of small-scale active regions. In particular, to examine how the large-scale geometry of the magnetic field, shaped by different phases of reconnection, guides the flowing of surges. Methods: We present three flux emergence models. The first model, and the simplest, consists of a region emerging into a horizontal ambient field that is initially parallel to the top of the emerging region. The second model is the same as the first but with an extra smaller emerging region which perturbs the main region. This is added to create a more complex magnetic topology and to test how this complicates the development of surges compared to the first model. The last model has a non-uniform ambient magnetic field to model the effects of emergence near a sunspot field and impose asymmetry on the system through the ambient magnetic field. At each stage, we trace the magnetic topology to identify the locations of reconnection. T...

  11. The statistical analysis of energy release in small-scale coronal structures

    Science.gov (United States)

    Ulyanov, Artyom; Kuzin, Sergey; Bogachev, Sergey

    We present the results of statistical analysis of impulsive flare-like brightenings, which numerously occur in the quiet regions of solar corona. For our study, we utilized high-cadence observations performed with two EUV-telescopes - TESIS/Coronas-Photon and AIA/SDO. In total, we processed 6 sequences of images, registered throughout the period between 2009 and 2013, covering the rising phase of the 24th solar cycle. Based on high-speed DEM estimation method, we developed a new technique to evaluate the main parameters of detected events (geometrical sizes, duration, temperature and thermal energy). We then obtained the statistical distributions of these parameters and examined their variations depending on the level of solar activity. The results imply that near the minimum of the solar cycle the energy release in quiet corona is mainly provided by small-scale events (nanoflares), whereas larger events (microflares) prevail on the peak of activity. Furthermore, we investigated the coronal conditions that had specified the formation and triggering of registered flares. By means of photospheric magnetograms obtained with MDI/SoHO and HMI/SDO instruments, we examined the topology of local magnetic fields at different stages: the pre-flare phase, the peak of intensity and the ending phase. To do so, we introduced a number of topological parameters including the total magnetic flux, the distance between magnetic sources and their mutual arrangement. The found correlation between the change of these parameters and the formation of flares may offer an important tool for application of flare forecasting.

  12. Structural and magnetic properties of ultra-small scale eutectic CoFeZr alloys

    International Nuclear Information System (INIS)

    Highlights: • Development of ultra-small scale eutectic CoFeZr alloys. • Hardness of 713 VHN was obtained for Co49.2Fe49.2Zr by lamellar spacing of 113 nm. • Highest moment of 1.92 μB at 5 K was obtained for Co49.2Fe49.2Zr. • Decay of magnetization at low temperature can be described by spin wave excitation. - Abstract: Aiming to develop high mechanical strength and toughness by tuning ultrafine lamellar spacing of magnetic eutectic alloys, we report the mechanical and magnetic properties of the binary eutectic alloys Co90.5Zr9.5 and Fe90.2Zr9.8, as well as the pseudo-binary eutectic alloys Co82.4Fe8Zr9.6, Co78Fe12.4Zr9.6 and Co49.2Fe49.2Zr9.6 developed by suction-casting. The lower lamellar spacing around 100 nm of the eutectics Co49.2Fe49.2Zr9.6 yields a high hardness of 713(±20) VHN. Magnetic measurements reveal high magnetic moment of 1.92 μB (at 5 K) and 1.82 μB (at 300 K) per formula unit for this composition. The magnetization vs. applied field data at 5 K show a directional preference to some extent and therefore smaller non-collinear magnetization behavior compared to Co11Zr2 reported in the literature due to exchange frustration and transverse spin freezing owing to the presence of smaller Zr content. The decay of magnetization as a function of temperature along the easy axis of magnetization of all the eutectic compositions can be described fairly well by the spin wave excitation equation ΔM/M(0) = BT3/2 + CT5/2

  13. Small-scale habitat structure modulates the effects of no-take marine reserves for coral reef macroinvertebrates.

    Directory of Open Access Journals (Sweden)

    Pascal Dumas

    Full Text Available No-take marine reserves are one of the oldest and most versatile tools used across the Pacific for the conservation of reef resources, in particular for invertebrates traditionally targeted by local fishers. Assessing their actual efficiency is still a challenge in complex ecosystems such as coral reefs, where reserve effects are likely to be obscured by high levels of environmental variability. The goal of this study was to investigate the potential interference of small-scale habitat structure on the efficiency of reserves. The spatial distribution of widely harvested macroinvertebrates was surveyed in a large set of protected vs. unprotected stations from eleven reefs located in New Caledonia. Abundance, density and individual size data were collected along random, small-scale (20×1 m transects. Fine habitat typology was derived with a quantitative photographic method using 17 local habitat variables. Marine reserves substantially augmented the local density, size structure and biomass of the target species. Density of Trochus niloticus and Tridacna maxima doubled globally inside the reserve network; average size was greater by 10 to 20% for T. niloticus. We demonstrated that the apparent success of protection could be obscured by marked variations in population structure occurring over short distances, resulting from small-scale heterogeneity in the reef habitat. The efficiency of reserves appeared to be modulated by the availability of suitable habitats at the decimetric scale ("microhabitats" for the considered sessile/low-mobile macroinvertebrate species. Incorporating microhabitat distribution could significantly enhance the efficiency of habitat surrogacy, a valuable approach in the case of conservation targets focusing on endangered or emblematic macroinvertebrate or relatively sedentary fish species.

  14. Small-Scale Structure of O VI Interstellar Gas in the Direction of the Globular Cluster NGC 6752

    OpenAIRE

    Lehner, N.; Howk, J. C.

    2004-01-01

    In order to study the small-scale structure of the hot interstellar gas, we obtained Far Ultraviolet Spectroscopic Explorer interstellar O VI interstellar absorption spectra of 4 four post-extreme horizontal branch stars in the globular cluster NGC 6752 [(l,b) = (336.50,-25.63), d = 3.9 kpc, z= -1.7 kpc]. The good quality spectra of these stars allow us to measure both lines of the O VI doublet at 1031.926 \\AA and 1037.617 \\AA. The close proximity of these stars permits us to probe the hot in...

  15. Structural and magnetic properties of ultra-small scale eutectic CoFeZr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Manjura Hoque, S. [Dept. of Materials Engineering, Indian Institute of Science, Bangalore (India); Materials Science Division, Atomic Energy Centre, Bangladesh Atomic Energy Commission, Dhaka (Bangladesh); Makineni, S.K. [Dept. of Materials Engineering, Indian Institute of Science, Bangalore (India); Pal, A.; Ayyub, P. [Dept. of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai (India); Chattopadhyay, K. [Dept. of Materials Engineering, Indian Institute of Science, Bangalore (India)

    2015-01-25

    Highlights: • Development of ultra-small scale eutectic CoFeZr alloys. • Hardness of 713 VHN was obtained for Co{sub 49.2}Fe{sub 49.2}Zr by lamellar spacing of 113 nm. • Highest moment of 1.92 μ{sub B} at 5 K was obtained for Co{sub 49.2}Fe{sub 49.2}Zr. • Decay of magnetization at low temperature can be described by spin wave excitation. - Abstract: Aiming to develop high mechanical strength and toughness by tuning ultrafine lamellar spacing of magnetic eutectic alloys, we report the mechanical and magnetic properties of the binary eutectic alloys Co{sub 90.5}Zr{sub 9.5} and Fe{sub 90.2}Zr{sub 9.8}, as well as the pseudo-binary eutectic alloys Co{sub 82.4}Fe{sub 8}Zr{sub 9.6}, Co{sub 78}Fe{sub 12.4}Zr{sub 9.6} and Co{sub 49.2}Fe{sub 49.2}Zr{sub 9.6} developed by suction-casting. The lower lamellar spacing around 100 nm of the eutectics Co{sub 49.2}Fe{sub 49.2}Zr{sub 9.6} yields a high hardness of 713(±20) VHN. Magnetic measurements reveal high magnetic moment of 1.92 μ{sub B} (at 5 K) and 1.82 μ{sub B} (at 300 K) per formula unit for this composition. The magnetization vs. applied field data at 5 K show a directional preference to some extent and therefore smaller non-collinear magnetization behavior compared to Co{sub 11}Zr{sub 2} reported in the literature due to exchange frustration and transverse spin freezing owing to the presence of smaller Zr content. The decay of magnetization as a function of temperature along the easy axis of magnetization of all the eutectic compositions can be described fairly well by the spin wave excitation equation ΔM/M(0) = BT{sup 3/2} + CT{sup 5/2}.

  16. A Measurement of Small Scale Structure in the 2.2 < z < 4.2 Lyman-alpha Forest

    CERN Document Server

    Lidz, Adam; Dall'Aglio, Aldo; McQuinn, Matthew; Fechner, Cora; Zaldarriaga, Matias; Hernquist, Lars; Dutta, Suvendra

    2009-01-01

    The amplitude of fluctuations in the Ly-a forest on small spatial scales is sensitive to the temperature of the IGM and its spatial fluctuations. The temperature of the IGM and its spatial variations contain important information about hydrogen and helium reionization. We present a new measurement of the small-scale structure in the Ly-a forest from 40 high resolution, high signal-to-noise, VLT spectra at z=2.2-4.2. We convolve each Ly-a forest spectrum with a suitably chosen wavelet filter, which allows us to extract the amount of small-scale structure in the forest as a function of position across each spectrum. We compare these measurements with high resolution hydrodynamic simulations of the Ly-a forest which track more than 2 billion particles. This comparison suggests that the IGM temperature close to the cosmic mean density (T_0) peaks near z=3.4, at which point it is greater than 20,000 K at 2-sigma confidence. The temperature at lower redshift is consistent with the fall-off expected from adiabatic c...

  17. Reconstructing our Interstellar Past: A Look at the Small Scale Structure in the Direction of the Historical Solar Trajectory

    Science.gov (United States)

    Redfield, S.; Scalo, J.; Smith, D. S.

    2007-07-01

    The properties of our nearby interstellar medium (NISM) out to ˜500 pc, including density, temperature, and velocity, provide a sample of the range and timing of environments that have been encountered by our solar system. These conditions influence the structure of the heliosphere, which modulates the flux of Galactic cosmic rays and interstellar gas and dust that reach the Earth. There is a long tradition of speculation focused on the effects of the ISM on heliospheric modulation of cosmic rays and interstellar hydrogen on atmospheric chemistry, cloud cover, glaciation episodes, and exogenous mutation, but the intensity and timing of such variations has never been established empirically, even in a statistical sense. The present work is aimed at evaluating the impact of small scale low column density structures in the NISM, using analysis of absorption line features toward early type stars, on the intensity and timing of heliospheric variations, and at placing these structures, invisible by most other techniques of tracing interstellar structure, in the overall dynamics of the interstellar medium. We present high spectral resolution observations of 49 stars within 10 degrees of the direction of the historical solar trajectory. This densely packed collection of sightlines provides an opportunity to (1) study small-scale structure in the shell separating the Local Bubble from the more distant NISM, (2) enable a rough reconstruction of the interstellar density profile, and hence cosmic ray flux history, encountered by the Solar System in the past 40 million years, and (3) clarify the prevalence of small column density fluctuations in the NISM.

  18. On the properties of slow mhd sausage waves within small-scale photospheric magnetic structures

    CERN Document Server

    Freij, N; Morton, R J; Ruderman, M S; Karlovsky, V; Erdekyi, R

    2015-01-01

    The presence of magneto-acoustic waves in magnetic structures in the solar atmosphere is well-documented. Applying the technique of solar magneto-seismology (SMS) allows us to infer the background properties of these structures. Here, we aim to identify properties of the observed magneto-acoustic waves and study the background properties of magnetic structures within the lower solar atmosphere. Using the Dutch Open Telescope (DOT) and Rapid Oscillations in the Solar Atmosphere (ROSA) instruments, we captured two series of high-resolution intensity images with short cadence of two isolated magnetic pores. Combining wavelet analysis and empirical mode decomposition (EMD), we determined characteristic periods within the cross-sectional (i.e., area) and intensity time series. Then, by applying the theory of linear magnetohydrodynamics (MHD), we identified the mode of these oscillations within the MHD framework. Several oscillations have been detected within these two magnetic pores. Their periods range from 3 to ...

  19. DETECTION OF SMALL-SCALE GRANULAR STRUCTURES IN THE QUIET SUN WITH THE NEW SOLAR TELESCOPE

    International Nuclear Information System (INIS)

    Results of a statistical analysis of solar granulation are presented. A data set of 36 images of a quiet-Sun area on the solar disk center was used. The data were obtained with the 1.6 m clear aperture New Solar Telescope at Big Bear Solar Observatory and with a broadband filter centered at the TiO (705.7 nm) spectral line. The very high spatial resolution of the data (diffraction limit of 77 km and pixel scale of 0.''0375) augmented by the very high image contrast (15.5% ± 0.6%) allowed us to detect for the first time a distinct subpopulation of mini-granular structures. These structures are dominant on spatial scales below 600 km. Their size is distributed as a power law with an index of –1.8 (which is close to the Kolmogorov's –5/3 law) and no predominant scale. The regular granules display a Gaussian (normal) size distribution with a mean diameter of 1050 km. Mini-granular structures contribute significantly to the total granular area. They are predominantly confined to the wide dark lanes between regular granules and often form chains and clusters, but different from magnetic bright points. A multi-fractality test reveals that the structures smaller than 600 km represent a multi-fractal, whereas on larger scales the granulation pattern shows no multi-fractality and can be considered as a Gaussian random field. The origin, properties, and role of the population of mini-granular structures in the solar magnetoconvection are yet to be explored.

  20. Lens-Aided Multi-Angle Spectroscopy (LAMAS) Reveals Small-Scale Outflow Structure in Quasars

    CERN Document Server

    Green, P J

    2006-01-01

    Spectral differences between lensed quasar image components are common. Since lensing is intrinsically achromatic, these differences are typically explained as the effect of either microlensing, or as light path time delays sampling intrinsic quasar spectral variability. Here we advance a novel third hypothesis: some spectral differences are due to small line-of-sight differences through quasar disk wind outflows. In particular, we propose that variable spectral differences seen only in component A of the widest separation lens SDSSJ1004+4112 are due to differential absorption along the sightlines. The absorber properties required by this hypothesis are akin to known broad absorption line (BAL) outflows but must have a broader, smoother velocity profile. We interpret the observed CIV emission line variability as further evidence for spatial fine structure transverse to the line of sight. Since outflows are likely to be rotating, such absorber fine structure can consistently explain some of the UV and X-ray va...

  1. Spurious Small-Scale Structure & Discreteness-Driven Relaxation in Cosmological Simulations

    OpenAIRE

    Power, Chris; Robotham, Aaron S. G.; Obreschkow, Danail; Hobbs, Alexander; Lewis, Geraint F.

    2016-01-01

    There is strong evidence that cosmological N-body simulations dominated by Warm Dark Matter (WDM) contain spurious or unphysical haloes, most readily apparent as regularly spaced low-mass haloes strung along filaments. We show that spurious haloes are a feature of traditional N-body simulations of cosmological structure formation models, including WDM and Cold Dark Matter (CDM) models, in which gravitational collapse proceeds in an initially anisotropic fashion, and arises naturally as a cons...

  2. Adjoint-tomography Inversion of the Small-scale Surface Sedimentary Structures: Key Methodological Aspects

    Science.gov (United States)

    Kubina, Filip; Moczo, Peter; Kristek, Jozef; Michlik, Filip

    2016-04-01

    Adjoint tomography has proven an irreplaceable useful tool in exploring Earth's structure in the regional and global scales. It has not been widely applied for improving models of local surface sedimentary structures (LSSS) in numerical predictions of earthquake ground motion (EGM). Anomalous earthquake motions and corresponding damage in earthquakes are often due to site effects in local surface sedimentary basins. Because majority of world population is located atop surface sedimentary basins, it is important to predict EGM at these sites during future earthquakes. A major lesson learned from dedicated international tests focused on numerical prediction of EGM in LSSS is that it is hard to reach better agreement between data and synthetics without an improved structural model. If earthquake records are available for sites atop a LSSS it is natural to consider them for improving the structural model. Computationally efficient adjoint tomography might be a proper tool. A seismic wavefield in LSSS is relatively very complex due to diffractions, conversions, interference and often also resonant phenomena. In shallow basins, the first arrivals are not suitable for inversion due to almost vertical incidence and thus insufficient vertical resolution. Later wavefield consists mostly of local surface waves often without separated wave groups. Consequently, computed kernels are complicated and not suitable for inversion without pre-processing. The spatial complexity of a kernel can be dramatic in a typical situation with relatively low number of sources (local earthquakes) and surface receivers. This complexity can be simplified by directionally-dependent smoothing and spatially-dependent normalization that condition reasonable convergence. A multiscale approach seems necessary given the usual difference between the available and true models. Interestingly, only a successive inversion of μ and λ elastic moduli, and different scale sequences lead to good results.

  3. Active structural acoustic control smart panel with small scale proof mass actuators

    OpenAIRE

    González Díaz, Cristóbal

    2007-01-01

    This thesis presents a comprehensive study of decentralised feedback control on a smart panel with electrodynamic proof mass actuators and velocity sensors at their footprints. The aim is to provide guidance for the design of light, simple, robust and low cost, control units which can be attached in large numbers to flexible structures in order to control their spatially averaged response and sound radiation at low audio-frequencies. The first part of the thesis is focused on t...

  4. On the Properties of Slow MHD Sausage Waves within Small-scale Photospheric Magnetic Structures

    Science.gov (United States)

    Freij, N.; Dorotovič, I.; Morton, R. J.; Ruderman, M. S.; Karlovský, V.; Erdélyi, R.

    2016-01-01

    The presence of magnetoacoustic waves in magnetic structures in the solar atmosphere is well-documented. Applying the technique of solar magneto-seismology (SMS) allows us to infer the background properties of these structures. Here, we aim to identify properties of the observed magnetoacoustic waves and study the background properties of magnetic structures within the lower solar atmosphere. Using the Dutch Open Telescope and Rapid Oscillations in the Solar Atmosphere instruments, we captured two series of high-resolution intensity images with short cadences of two isolated magnetic pores. Combining wavelet analysis and empirical mode decomposition (EMD), we determined characteristic periods within the cross-sectional (i.e., area) and intensity time series. Then, by applying the theory of linear magnetohydrodynamics (MHD), we identified the mode of these oscillations within the MHD framework. Several oscillations have been detected within these two magnetic pores. Their periods range from 3 to 20 minutes. Combining wavelet analysis and EMD enables us to confidently find the phase difference between the area and intensity oscillations. From these observed features, we concluded that the detected oscillations can be classified as slow sausage MHD waves. Furthermore, we determined several key properties of these oscillations such as the radial velocity perturbation, the magnetic field perturbation, and the vertical wavenumber using SMS. The estimated range of the related wavenumbers reveals that these oscillations are trapped within these magnetic structures. Our results suggest that the detected oscillations are standing harmonics, and this allows us to estimate the expansion factor of the waveguides by employing SMS. The calculated expansion factor ranges from 4 to 12.

  5. The Nippon/Norway Svalbard Meteor Radar: First results of small-scale structure observations

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Nippon/Norway Svalbard Meteor Radar(NSMR), has been in operation since March 2001. While primarily thought of as an instrument for examining mean wind, tidal and gravity wave neutral atmosphere dynamics in the upper mesosphere region, it is also possible to investigate spatial and temporal structure of temperature and windshear. Here, the radar itself is described followed by a presentation of these derived parameters.

  6. VLT/NACO infrared adaptive optics images of small scale structures in OMC1

    CERN Document Server

    Lacombe, F; Rouan, D; Clénet, Y; Lemaire, J L; Lagrange, A M; Mouillet, D; Rousset, G; Marlot, C; Feautrier, P; Gustafsson, M; Field, D; Lacombe, Francois; Gendron, Eric; Rouan, Daniel; Clenet, Yann; Lemaire, Jean-Louis; Lagrange, Anne-Marie; Mouillet, David; Rousset, Gerard; Marlot, Claude; Feautrier, Philippe; Field, David; Proxy, Bernard Servan; ccsd-00000915, ccsd

    2003-01-01

    Near-infrared observations of line emission from excited H2 and in the continuum are reported in the direction of the Orion molecular cloud OMC1, using the European Southern Observatory Very Large Telescope UT4, equipped with the NAOS adaptive optics system and the CONICA infrared array camera. Spatial resolution has been achieved at close to the diffraction limit of the telescope (0.08" - 0.12") and images show a wealth of morphological detail. Structure is not fractal but shows two preferred scale sizes of 2.4" (1100 AU) and 1.2" (540 AU), where the larger scale may be associated with star formation.

  7. Spurious Small-Scale Structure & Discreteness-Driven Relaxation in Cosmological Simulations

    CERN Document Server

    Power, Chris; Obreschkow, Danail; Hobbs, Alexander; Lewis, Geraint F

    2016-01-01

    There is strong evidence that cosmological N-body simulations dominated by Warm Dark Matter (WDM) contain spurious or unphysical haloes, most readily apparent as regularly spaced low-mass haloes strung along filaments. We show that spurious haloes are a feature of traditional N-body simulations of cosmological structure formation models, including WDM and Cold Dark Matter (CDM) models, in which gravitational collapse proceeds in an initially anisotropic fashion, and arises naturally as a consequence of discreteness-driven relaxation. We demonstrate this using controlled N-body simulations of plane-symmetric collapse and show that spurious haloes are seeded at shell crossing by localised velocity perturbations induced by the discrete nature of the density field, and that their characteristic separation should be approximately the mean inter-particle separation of the N-body simulation, which is fixed by the mass resolution within the volume. Using cosmological N-body simulations in which particles are split in...

  8. The correspondence between small-scale coronal structures and the evolving solar magnetic field

    International Nuclear Information System (INIS)

    Solar coronal bright points, first identified in soft X-rays as X-ray Bright Points (XBPs), are compact, short lived and associated with small bipolar magnetic flux. Contradictory studies have suggested that XBPs are either a primary signature of the emerging flux spectrum of the quiet Sun, or that they are representative of the disappearance of pre-existing flux. Results are presented using coordinated data obtained during recent X-ray sounding rocket flights on 15 August and 11 December 1987 to determine the correspondence of XBPs with time-series, ground based observations of evolving bipolar magnetic structures, He-I dark points, and the network. The results are consistent with the view that coronal bright points are more likely to be associated with the annihilation of pre-existing flux than with emerging flux

  9. A COMPACT HIGH VELOCITY CLOUD NEAR THE MAGELLANIC STREAM: METALLICITY AND SMALL-SCALE STRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Nimisha [Ecole Polytechnique, Route de Saclay, F-91128 Palaiseau (France); Fox, Andrew J.; Tumlinson, Jason; Thom, Christopher; Ely, Justin [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Westmeier, Tobias [ICRAR, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009 (Australia)

    2015-02-10

    The Magellanic Stream (MS) is a well-resolved gaseous tail originating from the Magellanic Clouds. Studies of its physical properties and chemical composition are needed to understand its role in Galactic evolution. We investigate the properties of a compact HVC (CHVC 224.0-83.4-197) lying close on the sky to the MS to determine whether it is physically connected to the Stream and to examine its internal structure. Our study is based on analysis of HST/COS spectra of three QSOs (Ton S210, B0120-28, and B0117-2837) all of which pass through this single cloud at small angular separation (≲0.°72), allowing us to compare physical conditions on small spatial scales. No significant variation is detected in the ionization structure from one part of the cloud to the other. Using Cloudy photoionization models, toward Ton S210 we derive elemental abundances of [C/H] = –1.21 ± 0.11, [Si/H] = –1.16 ± 0.11, [Al/H] = –1.19 ± 0.17, and [O/H] = –1.12 ± 0.22, which agree within 0.09 dex. The CHVC abundances match the 0.1 solar abundances measured along the main body of the Stream. This suggests that the CHVC (and by extension the extended network of filaments to which it belongs) has an origin in the MS. It may represent a fragment that has been removed from the Stream as it interacts with the gaseous Galactic halo.

  10. A COMPACT HIGH VELOCITY CLOUD NEAR THE MAGELLANIC STREAM: METALLICITY AND SMALL-SCALE STRUCTURE

    International Nuclear Information System (INIS)

    The Magellanic Stream (MS) is a well-resolved gaseous tail originating from the Magellanic Clouds. Studies of its physical properties and chemical composition are needed to understand its role in Galactic evolution. We investigate the properties of a compact HVC (CHVC 224.0-83.4-197) lying close on the sky to the MS to determine whether it is physically connected to the Stream and to examine its internal structure. Our study is based on analysis of HST/COS spectra of three QSOs (Ton S210, B0120-28, and B0117-2837) all of which pass through this single cloud at small angular separation (≲0.°72), allowing us to compare physical conditions on small spatial scales. No significant variation is detected in the ionization structure from one part of the cloud to the other. Using Cloudy photoionization models, toward Ton S210 we derive elemental abundances of [C/H] = –1.21 ± 0.11, [Si/H] = –1.16 ± 0.11, [Al/H] = –1.19 ± 0.17, and [O/H] = –1.12 ± 0.22, which agree within 0.09 dex. The CHVC abundances match the 0.1 solar abundances measured along the main body of the Stream. This suggests that the CHVC (and by extension the extended network of filaments to which it belongs) has an origin in the MS. It may represent a fragment that has been removed from the Stream as it interacts with the gaseous Galactic halo

  11. Reconstruction of the inner structure of small scale mining waste dumps by combining GPR and ERTdata.

    Science.gov (United States)

    Kniess, Rudolf; Martin, Tina

    2015-04-01

    Two abandoned small waste dumps in the west of the Harz mountains (Germany) were analysed using ground penetrating radar (GPR) and electrical resistivity tomography (ERT). Aim of the project (ROBEHA, funded by the German Federal Ministry of Education and Research (033R105)) is the assessment of the recycling potential of the mining residues taking into account environmental risks of reworking the dump site. One task of the geophysical prospection is the investigation of the inner structure of the mining dump. This is important for the estimation of the approximate volume of potentially reusable mining deposits within the waste dump. The two investigated dump sites are different in age and therefore differ in their structure. The older residues (separation (stamp mill sand). The younger dump site descends from comprises slag dump waste. The layer of fine grained residues at the first dump site is less than 6 m thick and the slag layer is less than 2 m thick. Both sites are partially overlain by forest or grassland vegetation and characterized by topographical irregularities. Due to the inhomogeneity of the sites we applied electrical resistivity tomography (ERT) and ground penetrating radar (GPR) for detailed investigation. Using ERT we could distinguish various layers within the mining dumps. The resistivities of the dumped material differ from the bedrock resistivities at both sites. The GPR measurements show near surface layer boundaries down to 3 - 4 m. In consecutive campaigns 100 MHz and 200 MHz antennas were used. The GPR results (layer boundaries) were included into the ERT inversion algorithm to enable more precise and stable resistivity models. This needs some special preprocessing steps. The 3D-Position of every electrode from ERT measurement and the GPR antenna position on the surface require an accuracy of less than 1cm. At some points, the layer boundaries and radar wave velocities can be calibrated with borehole stratigraphic data from a mineralogical

  12. Fluid-structure interactions in pressure-suppression pools: small-scale experiments

    International Nuclear Information System (INIS)

    Experiments were conducted in a laboratory scale system to investigate fluid structure interaction effects on hydrodynamically induced boundary pressure histories. A single flexible member - a clamped circular plate - formed the base of a rigid cylindrical water pool. Base plate thicknesses were varied to vary the natural frequency of the plate pool system. Two types of hydrodynamic transients were tested: the first, a pressure rise over the flat pool surface, the second, an air driven pool swell involving large liquid displacements and a more complicated boundary pressure history. Pressures at various points on the pool boundary and strains on the flexible base were measured. A one-dimensional analysis of the perturbation pressure transients induced by the deflections of the flexible base is compared with the experimental results. Ratios of the peak pressures in the flexible and rigid systems for two archetypal pressure transients - a monotonic rise of variable rise time and a pressure pulse of variable duration are predicted analytically and compared with the experiments

  13. Small-scale structure of the auroral electron and ion acceleration mechanisms

    International Nuclear Information System (INIS)

    High time resolution data obtained from sounding rocket flights reaching altitudes of 1,000 km now permit spatial measurements on the order of the particle gyrodiameters. The electron precipitation responsible for the auroral light emission has two distinct populations; the isotropic in pitch angle electrons that apparently have a magnetospheric source and have been further accelerated within one or two Re of the ionosphere, and, a very field-aligned component which is cold and apparently has an ionospheric source. The field-aligned component provides much of the fine structure and dynamic motion of the visual aurora. Time dispersion of these electrons also places their acceleration region one to two Re from the ionosphere. Much of the heavy ion population of the trapped radiation comes from the ionosphere. These ions apparently receive their initial acceleration transverse to B at altitudes on the order of 1,000 km during auroral events and then are further accelerated as they pass through the higher altitude auroral acceleration region. Recent measurements show that the volume of transverse ion acceleration can be as small as several tens of meters transverse to B and arc also volumes of ionospheric density depletion and intense waves near the lower hybrid frequency having electric field amplitudes of hundreds of mv/m. These regions of microscale transverse ion acceleration are generally co-located with the auroral field-aligned electron bursts

  14. Cosmological Simulations of Decaying Dark Matter: Implications for Small-scale Structure of Dark Matter Halos

    CERN Document Server

    Wang, Mei-Yu; Strigari, Louis E; Zentner, Andrew R; Arant, Bryan; Garrison-Kimmel, Shea; Rocha, Miguel

    2014-01-01

    We present a set of N-body simulations of a class of models in which an unstable dark matter particle decays into a stable non-interacting dark matter particle, with decay lifetime comparable to the Hubble time. We study the effects of the kinematic recoil velocity received by the stable dark matter on the structures of dark matter halos ranging from galaxy-cluster to Milky Way mass scales. For Milky Way-mass halos, we use high-resolution, zoom-in simulations to explore the effects of decays on Galactic substructure. In general, halos with circular velocities comparable to the magnitude of kick velocity are most strongly affected by decays. We show that decaying dark matter models with lifetimes comparable to Hubble time and recoil speeds about 20-40 km/s can significantly reduce both the abundance of Galactic subhalos and the internal densities of the subhalos. We also compare subhalo circular velocity profiles with observational constraints on the Milky Way dwarf satellite galaxies. Interestingly, we find t...

  15. Structure and dynamics of small scale magnetic fields in the solar atmosphere Results of high resolution polarimetry and image reconstruction

    Science.gov (United States)

    Janssen, K.

    2003-07-01

    Two-dimensional spectrograms were obtained at the Vacuum Tower Telescope, Tenerife, in order to study the structure of small scale magnetic fields on the Sun. The speckle reconstruction method that is used for data processing gives high resolution images and wavelength scans in left and right circular polarized light, from which magnetic field maps are calculated using the center of gravity method. The geometric similarity of magnetic structures is studied via the area- perimeter-relation, from which the Hausdorff-dimension of the rim of a structure is determined. The investigation shows that the actual value of the fractal dimension depends on the threshold that is used to determine the borders of the magnetic areas. Higher treshold values lead to smaller fractal dimensions. This can be explained by the concentration of strong magnetic fields while weak fields spread out in more complex structures. With a treshold of 80 Gauss a fractal dimension of D=1,40(5) is obtained. Furthermore, the dimension obtained by observed data is compared to the fractal dimension gained from MHD simulations. It is found that if the measurement scales are adjusted correctly the dimensions for both datasets match quite well. In a second part the dynamics of the mass motions were analysed and a coarse estimate of the energy conveyed by these movements to the magnetic field is given. The energy flux is strong enough to participate in the heating of the solar chromosphere and corona over active regions.

  16. An improved method to characterise the modulation of small-scale turbulent by large-scale structures

    Science.gov (United States)

    Agostini, Lionel; Leschziner, Michael; Gaitonde, Datta

    2015-11-01

    A key aspect of turbulent boundary layer dynamics is ``modulation,'' which refers to degree to which the intensity of coherent large-scale structures (LS) cause an amplification or attenuation of the intensity of the small-scale structures (SS) through large-scale-linkage. In order to identify the variation of the amplitude of the SS motion, the envelope of the fluctuations needs to be determined. Mathis et al. (2009) proposed to define this latter by low-pass filtering the modulus of the analytic signal built from the Hilbert transform of SS. The validity of this definition, as a basis for quantifying the modulated SS signal, is re-examined on the basis of DNS data for a channel flow. The analysis shows that the modulus of the analytic signal is very sensitive to the skewness of its PDF, which is dependent, in turn, on the sign of the LS fluctuation and thus of whether these fluctuations are associated with sweeps or ejections. The conclusion is that generating an envelope by use of a low-pass filtering step leads to an important loss of information associated with the effects of the local skewness of the PDF of the SS on the modulation process. An improved Hilbert-transform-based method is proposed to characterize the modulation of SS turbulence by LS structures

  17. Small scale module of the rat granular retrosplenial cortex: an example of minicolumn-like structure of the cerebral cortex

    Directory of Open Access Journals (Sweden)

    Noritaka eIchinohe

    2012-01-01

    Full Text Available Structures associated with the small scale module called minicolumn can be observed frequently in the cerebral cortex. However, the description of functional characteristics remains obscure. A significant confounding factor is the marked variability both in the definition of a minicolumn and in the diagnostic markers for identifying a minicolumn (see for review, Jones, 2000, DeFelipe et al., 2003; Rockland and Ichinohe, 2004. Within a minicolumn, cell columns are easily visualized by conventional Nissl staining. Dendritic bundles were first discovered with Golgi methods, but are more easily seen with MAP2-immunohistochemisty. Myelinated axon bundles can be seen by Tau-immunohistochemistry or myelin staining. Axon bundles of double bouquet cell can be seen by calbindin-immunohistochemistry. The spatial interrelationship among these morphological elements is more complex than expected and is neither clear nor unanimously agreed upon. In this review, I would like to focus first on the minicolumnar structure found in layers 1 and 2 of the rat granular retrosplenial cortex (GRS. This modular structure was first discovered as a combination of prominent apical dendritic bundles from layer 2 pyramidal neurons and spatially-matched thalamocortical patchy inputs (Wyss et al., 2000. Further examination showed more intricate components of this modular structure, which will be reviewed in this paper. Second, the postnatal development of this structure and potential molecular players for its formation will be reviewed. Thirdly, I will discuss how this modular organization is transformed in mutant rodents with a disorganized layer structure in the cerebral cortex (i.e., reeler mouse and Shaking Rat Kawasaki. Lastly, the potential significance of this type of module will be discussed.

  18. Large and small-scale structure of the Intermediate and High Velocity Clouds towards the LMC and SMC

    CERN Document Server

    Smoker, J V; Keenan, F P

    2015-01-01

    We employ CaII K and NaI D interstellar absorption-line spectroscopy of early-type stars in the Large and Small Magellanic Clouds to investigate the large- and small-scale structure in foreground Intermediate and High Velocity Clouds (I/HVCs). These data include FLAMES-GIRAFFE CaII K observations of 403 stars in four open clusters, plus FEROS or UVES spectra of 156 stars in the LMC and SMC. The FLAMES observations are amongst the most extensive probes to date of CaII structures on 20 arcsec scales From the FLAMES data within a 0.5 degree field-of-view, the CaII K equivalent width in the I/HVC components towards three clusters varies by factors of >10. There are no detections of molecular gas in absorption at intermediate or high velocities, although molecular absorption is present at LMC and Galactic velocities towards some sightlines. The sightlines show variations in EW exceeding a factor 7 in CH+ towards NGC 1761 over scales of less than 10 arcminutes. The FEROS/UVES data show CaII K I/HVC absorption in $\\...

  19. Small-Scale Structure of O VI Interstellar Gas in the Direction of the Globular Cluster NGC 6752

    CERN Document Server

    Lehner, N

    2004-01-01

    In order to study the small-scale structure of the hot interstellar gas, we obtained Far Ultraviolet Spectroscopic Explorer interstellar O VI interstellar absorption spectra of 4 four post-extreme horizontal branch stars in the globular cluster NGC 6752 [(l,b) = (336.50,-25.63), d = 3.9 kpc, z= -1.7 kpc]. The good quality spectra of these stars allow us to measure both lines of the O VI doublet at 1031.926 \\AA and 1037.617 \\AA. The close proximity of these stars permits us to probe the hot interstellar gas over angular scale of only $2\\farcm2 - 8\\farcm9$, corresponding to spatial scales $\\la 2.5-10.1$ pc. On these scales we detect no variations in the O VI column density and velocity distribution. The average column density is log = 14.34 \\pm 0.02 (log = 13.98). The measured velocity dispersions of the O VI absorption are also indistinguishable. Including the earlier results of Howk et al., this study suggests that interstellar O VI is smooth on scales $\\Delta \\theta \\la 12\\arcmin$, corresponding to a spati...

  20. Large- and small-scale structure of the intermediate- and high-velocity clouds towards the LMC and SMC

    Science.gov (United States)

    Smoker, J. V.; Fox, A. J.; Keenan, F. P.

    2015-08-01

    We employ Ca II K and Na I D interstellar absorption-line spectroscopy of early-type stars in the Large and Small Magellanic Clouds (LMC, SMC) to investigate the large- and small-scale structure in foreground intermediate- and high-velocity clouds (I/HVCs). Data include FLAMES-GIRAFFE Ca II K observations of 403 stars in four open clusters, plus FEROS or UVES spectra of 156 stars in the LMC and SMC. The FLAMES observations are amongst the most extensive probes to date of Ca II structures on ˜20 arcsec scales in Magellanic I/HVCs. From the FLAMES data within a 0.5° field of view, the Ca II K equivalent width in the I/HVC components towards three clusters varies by factors of ≥10. There are no detections of molecular gas in absorption at intermediate or high velocities, although molecular absorption is present at LMC and Galactic velocities towards some sightlines. The FEROS/UVES data show Ca II K I/HVC absorption in ˜60 per cent of sightlines. The range in the Ca II/Na I ratio in I/HVCs is from -0.45 to +1.5 dex, similar to previous measurements for I/HVCs. In 10 sightlines we find Ca II/O I ratios in I/HVC gas ranging from 0.2 to 1.5 dex below the solar value, indicating either dust or ionization effects. In nine sightlines I/HVC gas is detected in both H I and Ca II at similar velocities, implying that the two elements form part of the same structure.

  1. Associations between Small-scale Structure in Local Galactic Neutral Hydrogen and in the Cosmic Microwave Background Observed by PLANCK

    Science.gov (United States)

    Verschuur, Gerrit L.

    2015-11-01

    High-resolution galactic neutral hydrogen (HI) data obtained with the Green Bank Telescope (GBT) over 56 square degrees of sky around l = 132°, b = 25° are compared with small-scale structure in the Cosmic Microwave Background observed by PLANCK, specifically at 143 and 857 GHz, as well as with 100 μm observations from the IRIS survey. The analysis uses data in 13 2° × 2° sub-areas found in the IRSA database at IPAC. The results confirm what has been reported previously; nearby galactic HI features and high-frequency continuum sources believed to be cosmological are in fact clearly associated. While several attempts strongly suggest that the associations are statistically significant, the key to understanding the phenomenon lies in the fact that in any given area HI is associated with cirrus dust at certain HI velocities and with 143 GHz features at different velocities. At the same time, for the 13 sub-areas studied, there is very little overlap between the dust and 143 GHz features. The data do not imply that the HI itself gives rise to the high-frequency continuum emission. Rather, they appear to indicate undiagnosed brightness enhancements indirectly associated with the HI. If low density interstellar electrons concentrated into clumps, or observed in directions where their integrated line-of-sight column densities are greater than the background in a manner similar to the phenomena that give rise to structure in diffuse HI structure, they will profoundly affect attempts to create a foreground electron mask used for processing PLANCK as well as WMAP data.

  2. Small scale optics

    CERN Document Server

    Yupapin, Preecha

    2013-01-01

    The behavior of light in small scale optics or nano/micro optical devices has shown promising results, which can be used for basic and applied research, especially in nanoelectronics. Small Scale Optics presents the use of optical nonlinear behaviors for spins, antennae, and whispering gallery modes within micro/nano devices and circuits, which can be used in many applications. This book proposes a new design for a small scale optical device-a microring resonator device. Most chapters are based on the proposed device, which uses a configuration know as a PANDA ring resonator. Analytical and nu

  3. Small scale seismic measurement bench to assess imaging methods - application to Full Waveform Inversion of a shallow structure

    Science.gov (United States)

    Leparoux, D.; Bretaudeau, F.; Brossier, R.; Operto, S.; Virieux, J.

    2011-12-01

    Seismic imaging of subsurface is useful for civil engineering and landscape management topics. The usual methods use surface waves phase velocities or first arrival times of body waves. However, for complex structures, such methods can be inefficient and Full Waveform Inversion (FWI) promises relevant performances because all the signal is taken into account. FWI has been originally developed for deep explorations (Pratt et al. 1999). Heterogeneities and strong attenuation in the near surface make difficult the adaptation of the FWI to shallower media (Bretaudeau et al. 2009). For this reason, we have developed a physical modeling measurement bench that performs small scale seismic recording in well controlled contexts (Bretaudeau et al. 2011). In this paper we assess the capacity of the FWI method (Brossier 2010) for imaging a subsurface structure including a low velocity layer and a lateral variation of interfaces. The analog model is a 180mm long and 50mm thick layered epoxy resin block (fig. 1). Seismic data generated with a punctual piezoelectric source emitting a 120KHz Ricker wavelet at the medium surface were collected by an heterodyne laser interferometer. The laser allows recording the absolute normal particle displacement without contact, avoiding disturbances caused by coupling. The laser interferometer and the piezoelectric source were attached to automated arms that could be moved over the model surface to a precision of 0.01mm (fig. 1). The acquisition survey includes 241 receiver and 37 source positions respectively spaced at 1 and 5 mm. Figure 2 shows 2D maps of the Vs parameter after inversion of data sequentially processed with 13 frequencies. The geometry of the sloped interface is recovered. A low velocity zone is imaged but with a thickness thinner than expected. Moreover, artifacts appear in the near surface. Experimental modeling results showed the capacity of the FWI in this case and provided key issues for further works about inversion by

  4. Structure of small-scale field-aligned currents at middle and low latitudes having lower atmospheric origin

    Science.gov (United States)

    Nakanishi, K.; Iyemori, T.; Luhr, H.; Aoyama, T.

    2014-12-01

    The CHAMP magnetic data indicate that small amplitude (1-5 nT) magnetic fluctuations with period around a few tens of seconds along the orbit exist globally and almost all the time. Characteristics of the magnetic fluctuations including seasonal dependence having geographical characteristics strongly suggest that they are the small-scale spatial structure of field-aligned currents with lower atmospheric origin (Nakanishi et al., 2014). We suppose that gravity waves generated by lower atmospheric disturbances propagate to the ionosphere and drive the E-layer dynamo. The currents in the ionosphere divert along the magnetic field into the other hemisphere and make a closed circuit. To confirm the above scenario and to find the scale of the current circuit in longitudinal direction, we use the magnetic data observed by the SWARM satellites. By analysis of the magnetic data observed by the SWARM satellites, the magnetic fluctuations as recorded earlier by CHAMP are confirmed to have the same characteristics i.e., the magnetic fluctuation is perpendicular to the geomagnetic field; the amplitude on the dayside is much larger than that on the nightside; towards the dip equator the period tends to get longer. Because the three Swarm satellites have various spatial relations in 3-D space between their orbits, we could easily confirm that the objective magnetic fluctuations are not temporal but spatial structures. The longitudinal scale seems to be of the order of 100 km. We shall show the above results and some other characteristics of the current circuit and discuss whether or not our suggested model fits the observed characteristics.

  5. Image restoration and superresolution as probes of small scale far-IR structure in star forming regions

    International Nuclear Information System (INIS)

    Far-infrared continuum studies from the Kuiper Airborne Observatory are described that are designed to fully exploit the small-scale spatial information that this facility can provide. This work gives the clearest picture to date on the structure of galactic and extragalactic star forming regions in the far infrared. Work is presently being done with slit scans taken simultaneously at 50 and 100 microns, yielding one-dimensional data. Scans of sources in different directions have been used to get certain information on two dimensional structure. Planned work with linear arrays will allow us to generalize our techniques to two dimensional image restoration. For faint sources, spatial information at the diffraction limit of the telescope is obtained, while for brighter sources, nonlinear deconvolution techniques have allowed us to improve over the diffraction limit by as much as a factor of four. Information on the details of the color temperature distribution is derived as well. This is made possible by the accuracy with which the instrumental point-source profile (PSP) is determined at both wavelengths. While these two PSPs are different, data at different wavelengths can be compared by proper spatial filtering. Considerable effort has been devoted to implementing deconvolution algorithms. Nonlinear deconvolution methods offer the potential of superresolution -- that is, inference of power at spatial frequencies that exceed D lambda. This potential is made possible by the implicit assumption by the algorithm of positivity of the deconvolved data, a universally justifiable constraint for photon processes. We have tested two nonlinear deconvolution algorithms on our data; the Richardson-Lucy (R-L) method and the Maximum Entropy Method (MEM). The limits of image deconvolution techniques for achieving spatial resolution are addressed

  6. SMALL SCALE MORPHODYNAMICAL MODELLING

    Institute of Scientific and Technical Information of China (English)

    D. Ditschke; O. Gothel; H. Weilbeer

    2001-01-01

    Long term morphological simulations using complete coupled models lead to very time consuming computations. Latteux (1995) presented modelling techniques developed for tidal current situations in order to reduce the computational effort. In this paper the applicability of such methods to small scale problems is investigated. It is pointed out that these methods can be transferred to small scale problems using the periodicity of the vortex shedding process.

  7. The large scale instability and nonlinear vortex structures in obliquely rotating fluid with small scale non spiral force

    International Nuclear Information System (INIS)

    In this paper, we find a new large scale instability which appears in obliquely rotating flow with the small scale turbulence, generated by external force with small Reynolds number. The external force has no helicity. The theory is based on the rigorous method of multi scale asymptotic expansion. Nonlinear equations for instability are obtained in third order of the perturbation theory. In this article, we explain in details the nonlinear stage of the instability and we find the nonlinear periodic vortices and the vortex kinks of Beltrami type

  8. Wavelet transform analysis of the small-scale X-ray structure of the cluster Abell 1367

    Science.gov (United States)

    Grebeney, S. A.; Forman, W.; Jones, C.; Murray, S.

    1995-01-01

    We have developed a new technique based on a wavelet transform analysis to quantify the small-scale (less than a few arcminutes) X-ray structure of clusters of galaxies. We apply this technique to the ROSAT position sensitive proportional counter (PSPC) and Einstein high-resolution imager (HRI) images of the central region of the cluster Abell 1367 to detect sources embedded within the diffuse intracluster medium. In addition to detecting sources and determining their fluxes and positions, we show that the wavelet analysis allows a characterization of the sources extents. In particular, the wavelet scale at which a given source achieves a maximum signal-to-noise ratio in the wavelet images provides an estimate of the angular extent of the source. To account for the widely varying point response of the ROSAT PSPC as a function of off-axis angle requires a quantitative measurement of the source size and a comparison to a calibration derived from the analysis of a Deep Survey image. Therefore, we assume that each source could be described as an isotropic two-dimensional Gaussian and used the wavelet amplitudes, at different scales, to determine the equivalent Gaussian Full Width Half-Maximum (FWHM) (and its uncertainty) appropriate for each source. In our analysis of the ROSAT PSPC image, we detect 31 X-ray sources above the diffuse cluster emission (within a radius of 24 min), 16 of which are apparently associated with cluster galaxies and two with serendipitous, background quasars. We find that the angular extents of 11 sources exceed the nominal width of the PSPC point-spread function. Four of these extended sources were previously detected by Bechtold et al. (1983) as 1 sec scale features using the Einstein HRI. The same wavelet analysis technique was applied to the Einstein HRI image. We detect 28 sources in the HRI image, of which nine are extended. Eight of the extended sources correspond to sources previously detected by Bechtold et al. Overall, using both the

  9. Silica dust control in small-scale building/structure demolition operations using good work practice guidance

    International Nuclear Information System (INIS)

    Work practices can influence exposure, especially in small-scale operations conducted by mobile work crews. This study evaluated the use of information on good work practice in control guidance sheets adapted from UK Silica Essentials guidance sheets by trained workers and supervisors employed in small-scale concrete and masonry demolition operations. A one-page employee silica task-based control guidance sheet for each of four demolition tasks and multiple-page silica control guidance for supervisors were developed. Interactive, hands-on worker training on these task-based good work practice controls was developed. Training was presented to 26 participants from two demolition crews. Feedback on the training and task-based good work practice control guidance sheets was elicited. Observations of work practices were made before and after training. Participants indicated gains in knowledge and checklists were used to document skill attainment. The quality of the training and usefulness of the material/skills was rated high by trainees. Increased use of water to suppress dust and wet cleaning methods on the job were documented following the training. Additional follow-up after training is required to determine long-term impact on sustained changes in work practices, and to evaluate the need for refresher training.

  10. Mapping and characterization of small-scale aeolian structures on Mars: An example from the MSL landing site in Gale Crater

    OpenAIRE

    Vaz, David A.; Silvestro, Simone

    2014-01-01

    A new set of methodologies, which allow a simple and fast mapping and characterization of small-scale aeolian structures on Mars is introduced in this work. We follow an object-based approach in which the bedform crestlines are automatically mapped and characterized. From the methodology validation, we conclude that the quality of the obtained results is comparable with human-produced photointerpretations. We show that the accuracy associated with the measurement of mean trends from the a...

  11. Rolling at small scales

    DEFF Research Database (Denmark)

    Nielsen, Kim L.; Niordson, Christian F.; Hutchinson, John W.

    2016-01-01

    The rolling process is widely used in the metal forming industry and has been so for many years. However, the process has attracted renewed interest as it recently has been adapted to very small scales where conventional plasticity theory cannot accurately predict the material response. It is well...... plasticity. Metals are known to be stronger when large strain gradients appear over a few microns; hence, the forces involved in the rolling process are expected to increase relatively at these smaller scales. In the present numerical analysis, a steady-state modeling technique that enables convergence...

  12. Retrieval of three-dimensional small scale structures in upper tropospheric/lower stratospheric composition as measured by GLORIA

    Directory of Open Access Journals (Sweden)

    M. Kaufmann

    2014-04-01

    Full Text Available The three-dimensional quantification of small scale processes in the upper troposphere and lower stratosphere is one of the challenges of current atmospheric research and requires the development of new measurement strategies. This work presents first results from the newly developed Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA obtained during the ESSenCe and TACTS/ESMVal aircraft campaigns. The focus of this work is on the so-called dynamics mode data characterized by a medium spectral and a very high spatial resolution. The retrieval strategy for the derivation of two- and three-dimensional constituent fields in the upper troposphere and lower stratosphere is presented. Uncertainties of the main retrieval targets (temperature, O3, HNO3 and CFC-12 and their spatial resolution are discussed. During ESSenCe, high resolution two-dimensional cross-sections have been obtained. Comparisons to collocated remote-sensing and in-situ data indicate a good agreement between the data sets. During TACTS/ESMVal a tomographic flight pattern to sense an intrusion of stratospheric air deep into the troposphere has been performed. This filament could be reconstructed with an unprecedented spatial resolution of better than 500 m vertically and 20 km × 20 km horizontally.

  13. The dynamical distance and intrinsic structure of the globular cluster omega Centauri

    CERN Document Server

    De van Ven, G; Verolme, E K; De Zeeuw, P T

    2005-01-01

    We determine the dynamical distance D, inclination i, mass-to-light ratio M/L and the intrinsic orbital structure of the globular cluster omega Cen, by fitting axisymmetric dynamical models to the ground-based proper motions of van Leeuwen et al. and line-of-sight velocities from four independent data-sets. We correct the observed velocities for perspective rotation caused by the space motion of the cluster, and show that the residual solid-body rotation component in the proper motions can be taken out without any modelling other than assuming axisymmetry. This also provides a tight constraint on D tan i. Application of our axisymmetric implementation of Schwarzschild's orbit superposition method to omega Cen reveals no dynamical evidence for a significant radial dependence of M/L. The best-fit dynamical model has a stellar V-band mass-to-light ratio M/L_V = 2.5 +/- 0.1 M_sun/L_sun and an inclination i = 50 +/- 4 degrees, which corresponds to an average intrinsic axial ratio of 0.78 +/- 0.03. The best-fit dyn...

  14. The effect of encroachments on structure impact loads during a pool swell transient based on small-scale testing

    International Nuclear Information System (INIS)

    Experiments were conducted to investigate suppression pool dynamics in boiling water reactor (BWR) containments which have large overhanging structures attached to the drywell wall. Several 1/10 linear scale air blowdown tests utilizing Froude scaling (balance of gravity and inertia forces) were performed in this tests series. The drywall pressure was measured and high speed movies were made of the pool response. The resultant pool response was a function of encroachment size. Small encroachments did not significantly alter the response obtained for he unobstructed pool. For the large radial and circumferential encroachment, however, the increased inertia of the extra water lifted by the rising bubble delayed the transient, resulting in much lower pool swell velocities. This led to a stable liquid surface at higher elevations, but the surface curvature coupled with the relatively low pool surface velocities significantly mitigates structure impact loadings

  15. Frozen-in Fractals All Around: Inferring the Large Scale Effects of Small-Scale Magnetic Structure

    CERN Document Server

    McAteer, R T James

    2015-01-01

    The large-scale structure of the magnetic field in the solar corona provides the energy to power large-scale solar eruptive events. Our physical understanding of this structure, and hence our ability to predict these events, is limited by the type of data currently available. It is shown that the multifractal spectrum is a powerful tool to study this structure, by providing a physical connection between the details of photospheric magnetic gradients and current density at all size scales. This uses concepts associated with geometric measure theory and the theory of weakly differentiable functions to compare Amp\\`{e}re's law to the wavelet-transform modulus maximum method. The H\\"{o}lder exponent provides a direct measure of the rate of change of current density across spatial size scales. As this measure is independent of many features of the data (pixel resolution, data size, data type, presence of quiet-Sun data), it provides a unique approach to studying magnetic-field complexity and hence a potentially po...

  16. Small-scale classification schemes

    DEFF Research Database (Denmark)

    Hertzum, Morten

    2004-01-01

    important means of discretely balancing the contractual aspect of requirements engineering against facilitating the users in an open-ended search for their system requirements. The requirements classification is analysed in terms of the complementary concepts of boundary objects and coordination mechanisms......Small-scale classification schemes are used extensively in the coordination of cooperative work. This study investigates the creation and use of a classification scheme for handling the system requirements during the redevelopment of a nation-wide information system. This requirements...... classification inherited a lot of its structure from the existing system and rendered requirements that transcended the framework laid out by the existing system almost invisible. As a result, the requirements classification became a defining element of the requirements-engineering process, though its main...

  17. Hidden Sector Hydrogen as Dark Matter: Small-scale Structure Formation Predictions and the Importance of Hyperfine Interactions

    CERN Document Server

    Boddy, Kimberly K; Kwa, Anna; Peter, Annika H G

    2016-01-01

    We study the atomic physics and the astrophysical implications of a model in which the dark matter is the analog of hydrogen in a secluded sector. The self interactions between dark matter particles include both elastic scatterings as well as inelastic processes due to a hyperfine transition. The self-interaction cross sections are computed by numerically solving the coupled Schr\\"{o}dinger equations for this system. We show that these self interactions exhibit the right velocity dependence to explain the low dark matter density cores seen in small galaxies while being consistent with all constraints from observations of clusters of galaxies. For a viable solution, the dark hydrogen mass has to be in 10--100 GeV range and the dark fine-structure constant has to be larger than 0.02. Precisely for this range of parameters, we show that significant cooling losses may occur due to inelastic excitations to the hyperfine state and subsequent decays, with implications for the evolution of low-mass halos and the earl...

  18. Small-Scale Surface Reconstruction and Volume Calculation of Soil Erosion in Complex Moroccan Gully Morphology Using Structure from Motion

    Directory of Open Access Journals (Sweden)

    Andreas Kaiser

    2014-07-01

    Full Text Available This study presents a computer vision application of the structure from motion (SfM technique in three dimensional high resolution gully monitoring in southern Morocco. Due to impractical use of terrestrial Light Detection and Ranging (LiDAR in difficult to access gully systems, the inexpensive SfM is a promising tool for analyzing and monitoring soil loss, gully head retreat and plunge pool development following heavy rain events. Objects with known dimensions were placed around the gully scenes for scaling purposes as a workaround for ground control point (GCP placement. Additionally, the free scaling with objects was compared to terrestrial laser scanner (TLS data in a field laboratory in Germany. Results of the latter showed discrepancies of 5.6% in volume difference for erosion and 1.7% for accumulation between SfM and TLS. In the Moroccan research area soil loss varied between 0.58 t in an 18.65 m2 narrowly stretched gully incision and 5.25 t for 17.45 m2 in a widely expanded headcut area following two heavy rain events. Different techniques of data preparation were applied and the advantages of SfM for soil erosion monitoring under complex surface conditions were demonstrated.

  19. Adaptive Airborne Doppler Wind Lidar Beam Scanning Patterns for Complex Terrain and Small Scale Organized Atmospheric Structure Observations

    Science.gov (United States)

    Emmitt, G.; O'Handley, C.; de Wekker, S. F.

    2008-12-01

    The conical scan is the traditional pattern used to obtain vertical profiles of the wind field with an airborne Doppler wind lidar. Nadir or zenith pointing scanning wedges are ideal for this type of scan. A bi-axis scanner has been operated on a Navy Twin Otter for more than 6 years and has been recently installed on a Navy P3 for use in a field experiment to study typhoons. The bi-axis scanner enables a broad range of scanning patterns. A subset of the possible patterns is critical to obtaining useful wind profiles in the presence of complex terrain or small (~ 100's of meters) organized atmospheric structures (rolls, updrafts, waves, etc). Several scanning strategies have been tested in flights over the Monterey Peninsula and within tropical cyclones. Combined with Google Earth (on-board) and satellite imagery overlays, new realtime adaptive scanning algorithms are being developed and tested. The results of these tests (both real and simulated) will be presented in the form of case studies.

  20. Effects of Proxima Centauri on Planet Formation in Alpha Centauri

    CERN Document Server

    Worth, R

    2016-01-01

    Proxima Centauri is an M dwarf approximately 15,000 AU from the Alpha Centauri binary, comoving and likely in a loosely bound orbit. Dynamic simulations show this configuration can form from a more tightly bound triple system. As our nearest neighbors, these stars command great interest as potential planet hosts, and the dynamics of the stars govern the formation of any planets within the system. Here we present a scenario for the evolution of Alpha Centauri A and B and Proxima Centauri as a triple system. Based on N-body simulations, we determine this pathway to formation is plausible, and we quantify the implications for planet formation in the Alpha Centauri binary. We expect this formation scenario may have truncated the circumstellar disk slightly more than a system that formed in the current configuration, but that it most likely does not prevent terrestrial planet formation. We simulate planet formation in this system and find that in most scenarios, two or more terrestrial planets can be expected arou...

  1. ETHOS - An Effective Theory of Structure Formation: Dark matter physics as a possible explanation of the small-scale CDM problems

    CERN Document Server

    Vogelsberger, Mark; Cyr-Racine, Francis-Yan; Pfrommer, Christoph; Bringmann, Torsten; Sigurdson, Kris

    2015-01-01

    We present the first simulations within an effective theory of structure formation (ETHOS), which includes the effect of interactions between dark matter and dark radiation on the linear initial power spectrum and dark matter self-interactions during non-linear structure formation. We simulate a Milky Way-like halo in four different dark matter models in addition to the cold dark matter case. Our highest resolution simulation has a particle mass of $2.8\\times 10^4\\,{\\rm M}_\\odot$ and a softening length of $72.4\\,{\\rm pc}$. We demonstrate that all alternative models have only a negligible impact on large scale structure formation and behave on those scales like cold dark matter. On galactic scales, however, the models significantly affect the structure and abundance of subhaloes due to the combined effects of small scale primordial damping in the power spectrum and the late time self-interaction rate in the center of subhaloes. We derive an analytic mapping from the primordial damping scale in the power spectr...

  2. ETHOS - an effective theory of structure formation: dark matter physics as a possible explanation of the small-scale CDM problems

    Science.gov (United States)

    Vogelsberger, Mark; Zavala, Jesús; Cyr-Racine, Francis-Yan; Pfrommer, Christoph; Bringmann, Torsten; Sigurdson, Kris

    2016-08-01

    We present the first simulations within an effective theory of structure formation (ETHOS), which includes the effect of interactions between dark matter and dark radiation on the linear initial power spectrum and dark matter self-interactions during non-linear structure formation. We simulate a Milky Way-like halo in four different dark matter models and the cold dark matter case. Our highest resolution simulation has a particle mass of 2.8 × 104 M⊙ and a softening length of 72.4 pc. We demonstrate that all alternative models have only a negligible impact on large-scale structure formation. On galactic scales, however, the models significantly affect the structure and abundance of subhaloes due to the combined effects of small-scale primordial damping in the power spectrum and late-time self-interactions. We derive an analytic mapping from the primordial damping scale in the power spectrum to the cutoff scale in the halo mass function and the kinetic decoupling temperature. We demonstrate that certain models within this extended effective framework that can alleviate the too-big-to-fail and missing satellite problems simultaneously, and possibly the core-cusp problem. The primordial power spectrum cutoff of our models naturally creates a diversity in the circular velocity profiles, which is larger than that found for cold dark matter simulations. We show that the parameter space of models can be constrained by contrasting model predictions to astrophysical observations. For example, some models may be challenged by the missing satellite problem if baryonic processes were to be included and even oversolve the too-big-to-fail problem; thus ruling them out.

  3. ETHOS - An Effective Theory of Structure Formation: Dark matter physics as a possible explanation of the small-scale CDM problems

    Science.gov (United States)

    Vogelsberger, Mark; Zavala, Jesús; Cyr-Racine, Francis-Yan; Pfrommer, Christoph; Bringmann, Torsten; Sigurdson, Kris

    2016-05-01

    We present the first simulations within an effective theory of structure formation (ETHOS), which includes the effect of interactions between dark matter and dark radiation on the linear initial power spectrum and dark matter self-interactions during non-linear structure formation. We simulate a Milky Way-like halo in four different dark matter models and the cold dark matter case. Our highest resolution simulation has a particle mass of 2.8× 10^4{ M_⊙} and a softening length of 72.4 pc. We demonstrate that all alternative models have only a negligible impact on large scale structure formation. On galactic scales, however, the models significantly affect the structure and abundance of subhaloes due to the combined effects of small scale primordial damping in the power spectrum and late time self-interactions. We derive an analytic mapping from the primordial damping scale in the power spectrum to the cutoff scale in the halo mass function and the kinetic decoupling temperature. We demonstrate that certain models within this extended effective framework that can alleviate the too-big-to-fail and missing satellite problems simultaneously, and possibly the core-cusp problem. The primordial power spectrum cutoff of our models naturally creates a diversity in the circular velocity profiles, which is larger than that found for cold dark matter simulations. We show that the parameter space of models can be constrained by contrasting model predictions to astrophysical observations. For example, some models may be challenged by the missing satellite problem if baryonic processes were to be included and even over-solve the too-big-to-fail problem; thus ruling them out.

  4. The large- and small-scale CaII K structure of the Milky Way from observations of Galactic and Magellanic sightlines

    CERN Document Server

    Smoker, J V; Fox, A J

    2015-01-01

    Aims: By utilising spectra of early-type stellar probes of known distances in the same region of the sky, the large and small-scale (pc) structure of the Galactic ISM can be investigated. This paper determines the variation in line strength of CaII at 3933.661 A, as a function of probe separation for a sample of stars, including many sightlines in the Magellanic Clouds. Methods: FLAMES-GIRAFFE data taken with the VLT towards early-type stars in 3 Galactic & 4 Magellanic open clusters in CaII are used to obtain the velocity, EW, column density and line width of IS Galactic Ca for a total of 657 stars, of which 443 are Magellanic sightlines. In each cluster there are 43-110 stars observed. Additionally, FEROS and UVES CaII & NaI spectra of 21 Galactic & 154 Magellanic early-type stars are presented and combined with data from the literature to study the Ca column density/parallax relationship. Results: For the four Magellanic clusters studied with FLAMES, the strength of the Galactic IS CaII K EW ov...

  5. Model Formulation of Apple Beverages for Production System in Micro Small Scale Enterprises (MSEs Using Generalized Structured Component Analysis (GSCA Method

    Directory of Open Access Journals (Sweden)

    Siti Asmaul Mustaniroh

    2014-05-01

    Full Text Available The goal of this study is to determine the model formulation of the production systems of apple beverages by including the quality of apple, the level of food additives, the condition of pasteurization and the quality of apple beverages. The sample of this research is Micro Small Scale Enterprises (MSEs of apple beverages in the Batu city, East Java Province using a sample of 20 people as the owners or production staff in MSEs. The methods of analysis is Generalized Structured Component Analysis (GSCA that the news model for measuring effect and corelation of latent variable in model. The results showed that the model is feasible to explain 35.7% of the variation in the quality of apple beverages. The condition of pasteurization had a significant effect at the 5% level (p-value <0.05, while the other variables (the quality of apples and the level of food additives had no significant effect on the quality of apple beverages. The novelty of this study that the quality of apple, the level of food additives, the condition of pasteurization and the qualty of apple beverages can expresion in the matematic model with GSCA analysis. The limitation of this study is that other variables in the apple beverages production not included in the model such as extraction, sterilization which one also critical in the production.

  6. Simulation of electrical characteristics and structural optimization for small-scaled dual-gate GeOI MOSFET with high-k gate dielectric

    International Nuclear Information System (INIS)

    The influences of the main structure and physical parameters of the dual-gate GeOI MOSFET on the device performance are investigated by using a TCAD 2D device simulator. A reasonable value range of germanium (Ge) channel thickness, doping concentration, gate oxide thickness and permittivity is determined by analyzing the on-state current, off-state current, short channel effect (SCE) and drain-induced barrier lowering (DIBL) effect of the GeOI MOSFET. When the channel thickness and its doping concentration are 10–18 nm and (5–9) × 1017 cm−3, and the equivalent oxide thickness and permittivity of the gate dielectric are 0.8–1 nm and 15–30, respectively, excellent device performances of the small-scaled GeOI MOSFET can be achieved: on-state current of larger than 1475 μA/μm, off-state current of smaller than 0.1 μA/μm, SCE-induced threshold-voltage drift of lower than 60 mV and DIBL-induced threshold-voltage drift of lower than 140 mV. (semiconductor devices)

  7. Chemical Evolution in Omega Centauri

    OpenAIRE

    Smith, Verne V.

    2003-01-01

    The globular cluster Omega Centauri displays evidence of a complex star formation history and peculiar internal chemical evolution, setting it apart from essentially all other globular clusters of the Milky Way. In this review we discuss the nature of the chemical evolution that has occurred within Omega Cen and attempt to construct a simple scenario to explain its chemistry.

  8. Simulation of large scale motions and small scale structures in planetary atmospheres and oceans: From laboratory to space experiments on ISS

    Science.gov (United States)

    Egbers, Christoph; Futterer, Birgit; Zaussinger, Florian; Harlander, Uwe

    2014-05-01

    Baroclinic waves are responsible for the transport of heat and momentum in the oceans, in the Earth's atmosphere as well as in other planetary atmospheres. The talk will give an overview on possibilities to simulate such large scale as well as co-existing small scale structures with the help of well defined laboratory experiments like the baroclinic wave tank (annulus experiment). The analogy between the Earth's atmosphere and the rotating cylindrical annulus experiment only driven by rotation and differential heating between polar and equatorial regions is obvious. From the Gulf stream single vortices seperate from time to time. The same dynamics and the co-existence of small and large scale structures and their separation can be also observed in laboratory experiments as in the rotating cylindrical annulus experiment. This experiment represents the mid latitude dynamics quite well and is part as a central reference experiment in the German-wide DFG priority research programme ("METSTRÖM", SPP 1276) yielding as a benchmark for lot of different numerical methods. On the other hand, those laboratory experiments in cylindrical geometry are limited due to the fact, that the surface and real interaction between polar and equatorial region and their different dynamics can not be really studied. Therefore, I demonstrate how to use the very successful Geoflow I and Geoflow II space experiment hardware on ISS with future modifications for simulations of small and large scale planetary atmospheric motion in spherical geometry with differential heating between inner and outer spheres as well as between the polar and equatorial regions. References: Harlander, U., Wenzel, J., Wang, Y., Alexandrov, K. & Egbers, Ch., 2012, Simultaneous PIV- and thermography measurements of partially blocked flow in a heated rotating annulus, Exp. in Fluids, 52 (4), 1077-1087 Futterer, B., Krebs, A., Plesa, A.-C., Zaussinger, F., Hollerbach, R., Breuer, D. & Egbers, Ch., 2013, Sheet-like and

  9. A formulation of convection for stellar structure and evolution calculations without the mixing-length theory approximations. II - Application to Alpha Centauri A and B

    Science.gov (United States)

    Lydon, Thomas J.; Fox, Peter A.; Sofia, Sabatino

    1993-01-01

    We have constructed a series of models of Alpha Centauri A and Alpha Centauri B for the purposes of testing the effects of convection modeling both by means of the mixing-length theory (MLT), and by means of parameterization of energy fluxes based upon numerical simulations of turbulent compressible convection. We demonstrate that while MLT, through its adjustable parameter alpha, can be used to match any given values of luminosities and radii, our treatment of convection, which lacks any adjustable parameters, makes specific predictions of stellar radii. Since the predicted radii of the Alpha Centauri system fall within the errors of the observed radii, our treatment of convection is applicable to other stars in the H-R diagram in addition to the sun. A second set of models is constructed using MLT, adjusting alpha to yield not the 'measured' radii but, instead, the radii predictions of our revised treatment of convection. We conclude by assessing the appropriateness of using a single value of alpha to model a wide variety of stars.

  10. Viable Small Scale Farming in Norway

    OpenAIRE

    Heie, Knut

    2003-01-01

    Norway, on Europe's northern fringe, is characterised by small-scale farming. The choice of crops and their yields are limited by the Nordic climate. Farm policies promote decentralisation and a varied farm structure in order to secure rural settlement, food security, food safety, environmental quality and sustainability. Agriculture receives substantial public support, and domestic production is largely protected from foreign competition. The author has a smallholding of 5 ha farmland and 15...

  11. Philippines: Small-scale renewable energy update

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    This paper gives an overview of the application of small scale renewable energy sources in the Philippines. Sources looked at include solar, biomass, micro-hydroelectric, mini-hydroelectric, wind, mini-geothermal, and hybrid. A small power utilities group is being spun off the major utility, to provide a structure for developing rural electrification programs. In some instances, private companies have stepped forward, avoiding what is perceived as overwhelming beaurocracy, and installed systems with private financing. The paper provides information on survey work which has been done on resources, and the status of cooperative programs to develop renewable systems in the nation.

  12. Fabrication of a small-scaled first wall mock-up with beryllium armor hip bonded to DSCu/SS structure

    International Nuclear Information System (INIS)

    For the bonding of beryllium (Be) and alumna dispersion strengthened copper (DSCu), Hot Isostatic Pressing (HIP) method has been tried. A preliminary study on optimal HIP conditions for the joining of Be/DSCu had been previously performed with various interlayer materials. Based on this previous study, an additional screening test was performed focusing on lower HIP temperatures to avoid stainless steel (SS) sensitization during HIP process. From the results of bending tests and microscopic observation of the HIPed interfaces, two options were selected as follows: 1) 580 deg.C HIP temperature with Ti/Cu interlayer and 2) 550 deg.C HIP temperature with A1/Ti/Cu interlayer. Based on the selection of above HIP conditions and interlayers, a small-scale first wall mock-up was fabricated. The mock-up consists of four 10 mm thick Be armor tiles, 20 mm thick DSCu heat sink with a built-in SS316L coolant tube and SS316L backing plate. After the DSCu heat sink and SS316L coolant tube and backing plate were joined by HIP, Be armor tiles were HIPed onto DSCu. Castellation of the Be armor was then carried out with 1.5 mm gap width between armor tiles. Among four Be tiles, two tiles were bonded with Ti/Cu interlayer and the other tiles with A1/Ti/Cu interlayer. (author)

  13. A High-Resolution X-Ray and Optical Study of SN1006: Asymmetric Expansion and Small-Scale Structure in a Type Ia Supernova Remnant

    Science.gov (United States)

    Winkler, P. Frank; Williams, Brian J.; Reynolds, Stephen P.; Petre, Robert; Long, Knox S.; Katsuda, Satoru; Hwang, Una

    2014-01-01

    We introduce a deep (670 ks) X-ray survey of the entire SN 1006 remnant from the Chandra X-Ray Observatory, together with a deep Ha image of SN 1006 from the 4 m Blanco telescope at CTIO. Comparison with Chandra images from 2003 gives the first measurement of the X-ray proper motions around the entire periphery, carried out over a 9 yr baseline. We find that the expansion velocity varies significantly with azimuth. The highest velocity of approx.7400 km/s (almost 2.5 times that in the northwest (NW)) is found along the southeast (SE) periphery, where both the kinematics and the spectra indicate that most of the X-ray emission stems from ejecta that have been decelerated little, if at all. Asymmetries in the distribution of ejecta are seen on a variety of spatial scales. Si-rich ejecta are especially prominent in the SE quadrant, while O and Mg are more uniformly distributed, indicating large-scale asymmetries arising from the explosion itself. Neon emission is strongest in a sharp filament just behind the primary shock along the NWrim, where the pre-shock density is highest. Here the Ne is likely interstellar, while Ne within the shell may include a contribution from ejecta. Within the interior of the projected shell we find a few isolated "bullets" of what appear to be supernova ejecta that are immediately preceded by bowshocks seen in Ha, features that we interpret as ejecta knots that have reached relatively dense regions of the surrounding interstellar medium, but that appear in the interior in projection. Recent three-dimensional hydrodynamic models for Type Ia supernovae display small-scale features that strongly resemble the ones seen in X-rays in SN 1006; an origin in the explosion itself or from subsequent hydrodynamic instabilities both remain viable options. We have expanded the search for precursor X-ray emission ahead of a synchrotron-dominated shock front, as expected from diffusive shock acceleration theory, to numerous regions along both the

  14. Oscillations in the Habitable Zone around Alpha Centauri B

    CERN Document Server

    Forgan, Duncan

    2012-01-01

    The Alpha Centauri AB system is an attractive one for radial velocity observations to detect potential exoplanets. The high metallicity of both Alpha Centauri A and B suggest that they could have possessed circumstellar discs capable of forming planets. As the closest star system to the Sun, with well over a century of accurate astrometric measurements (and Alpha Centauri B exhibiting low chromospheric activity) high precision surveys of Alpha Centauri B's potential exoplanetary system are possible with relatively cheap instrumentation. Authors studying habitability in this system typically adopt habitable zones (HZs) based on global radiative balance models that neglect the radiative perturbations of Alpha Centauri A. We investigate the habitability of planets around Alpha Centauri B using 1D latitudinal energy balance models (LEBMs), which fully incorporate the presence of Alpha Centauri A as a means of astronomically forcing terrestrial planet climates. We find that the extent of the HZ is relatively uncha...

  15. MOST Observations of our Nearest Neighbor: Flares on Proxima Centauri

    OpenAIRE

    Davenport, James R. A.; Kipping, David M.; Sasselov, Dimitar; Matthews, Jaymie M.; Cameron, Chris

    2016-01-01

    We present a study of white light flares from the active M5.5 dwarf Proxima Centauri using the Canadian microsatellite MOST. Using 37.6 days of monitoring data from 2014 and 2015, we have detected 66 individual flare events, the largest number of white light flares observed to date on Proxima Cen. Flare energies in our sample range from $10^{29}$-$10^{31.5}$ erg, with complex, multi-peaked structure found in 22% of these events. The flare rate is lower than that of other classic flare stars o...

  16. $\\alpha$ Centauri A in the far infrared

    CERN Document Server

    Liseau, R; Olofsson, G; Bryden, G; Marshall, J P; Ardila, D; Aran, A Bayo; Danchi, W C; del Burgo, C; Eiroa, C; Ertel, S; Fridlund, M C W; Krivov, A V; Pilbratt, G L; Roberge, A; Thébault, P; Wiegert, J; White, G J

    2012-01-01

    Chromospheres and coronae are common phenomena on solar-type stars. Understanding the energy transfer to these heated atmospheric layers requires direct access to the relevant empirical data. Study of these structures has, by and large, been limited to the Sun thus far. The region of the temperature reversal can be directly observed only in the far infrared and submm. We aim at the determination of the characteristics of the atmosphere in the region of the temperature minimum of the solar sister star alpha Cen A. For the nearby binary system alpha Centauri, stellar parameters are known with high accuracy from measurements. For the basic model parameters Teff, log g and [Fe/H], we interpolate in the grid of GAIA/PHOENIX stellar model atmospheres and compute the corresponding model for the G2 V star alpha Cen A. Comparison with photometric measurements shows excellent agreement between observed photospheric data in the optical and infrared. For longer wavelengths, the modelled spectral energy distribution is co...

  17. Method and system for small scale pumping

    Science.gov (United States)

    Insepov, Zeke; Hassanein, Ahmed

    2010-01-26

    The present invention relates generally to the field of small scale pumping and, more specifically, to a method and system for very small scale pumping media through microtubes. One preferred embodiment of the invention generally comprises: method for small scale pumping, comprising the following steps: providing one or more media; providing one or more microtubes, the one or more tubes having a first end and a second end, wherein said first end of one or more tubes is in contact with the media; and creating surface waves on the tubes, wherein at least a portion of the media is pumped through the tube.

  18. Associations between small-scale structure in the GALFA survey data of HI in the galactic disk and similar features in the Cosmic Microwave Background observed by PLANCK

    Science.gov (United States)

    Verschuur, Gerrit L.

    2016-01-01

    High-resolution HI data obtained as part of the Arecibo GALFA survey have been compared with PLANCK data at 143 GHz and 857 GHz. The analysis confirms what has been reported previously, that sources of high-frequency continuum radiation exist in the galactic interstellar medium that produce structure that has been incorrectly interpreted as being cosmological in origin. The mechanism appears to be free-free emission from electron concentrations in regions where the dust and HI are similarly clumped or otherwise enhanced due to geometric effects. By comparing model calculations with the data it is concluded that the source of the radiation is relatively close to the sun, or order 25 to 50 pc distant. The required ionization fraction relative to HI is of order 0.05 - 0.08 for the areas tested.

  19. Biomass for energy - small scale technologies

    Energy Technology Data Exchange (ETDEWEB)

    Salvesen, F.; Joergensen, P.F. [KanEnergi, Rud (Norway)

    1997-12-31

    The bioenergy markets and potential in EU region, the different types of biofuels, the energy technology, and the relevant applications of these for small-scale energy production are reviewed in this presentation

  20. Slip Dynamics in Small Scale Crystals

    Science.gov (United States)

    Maass, Robert; Derlet, Peter; Greer, Julia; Volkert, Cynthia

    2015-03-01

    Classical work showed that dislocation velocities are strongly dependent on applied stress. Numerous experiments have validated this for individual or groups of dislocations in macroscopic crystals by using imaging techniques combined with either mechanical data or time resolved topological data. Developments in small scale mechanical testing allow to correlate the intermittency of collective dislocation motion with the mechanical response. Discrete forward surges in displacement can be related to dislocation avalanches, which are triggered by the evolving dislocation sub-structure. We study the spatiotemporal characteristics of intermittent plastic flow in quasi-statically sheared single crystalline Au crystals with diameters between 300 nm and 10000 nm, whose displacement bursts were recorded at several kHz (Scripta Mater. 2013, 69, 586; Small, available online). Both the crystallographic slip magnitude, as well as the velocity of the slip events are exhibiting power-law scaling as. The obtained slip velocity distribution has a cubic decay at high values, and a saturated flat shoulder at lower velocities. No correlation between the slip velocity and the applied stress or plastic strain is found. Further, we present DD-simulations that are supportive of our experimental findings. The simulations suggest that the dynamics of the internal stress fields dominate the evolving dislocation structure leading to velocities that are insensitive to the applied stress - a regime indicative of microplasticity.

  1. Small-scale mechanical testing of materials

    OpenAIRE

    Jaya, Nagamani B; Alam, Md Zafir

    2013-01-01

    Small-scale mechanical testing of materials has gained prominence in the last decade or so due to the continuous miniaturization of components and devices in everyday application. This review describes the various micro-fabrication processes associated with the preparation of miniaturized specimens, geometries of test specimens and the small scale testing techniques used to determine the mechanical behaviour of materials at the length scales of a few hundred micro-meters and below. This is fo...

  2. Organizing small-scale scout trip abroad

    OpenAIRE

    Rautala, Camilla

    2016-01-01

    This thesis was commissioned by the Guides and Scouts of Finland (Suomen Partiolaiset – Finlands Scouter ry.) The thesis describes the organising process of a small-scale scout trip to the members of commissioning company. The Guides and Scouts of Finland directs the scout movement in Finland. The small-scale trips to national camps support the organisation’s objectives of educating world citizens. The objective of this thesis project was to plan and implemented well-organised trip to Bal...

  3. The Hydrodynamic Feedback of Cosmic Reionization on Small-Scale Structures and Its Impact on Photon Consumption during the Epoch of Reionization

    CERN Document Server

    Park, Hyunbae; Choi, Jun-hwan; Yoshida, Naoki; Hirano, Shingo; Ahn, Kyungjin

    2016-01-01

    Density inhomogeneity in the intergalactic medium (IGM) on sub-Mpc scales can boost the recombination rate of ionized gas substantially, affecting the growth of H II regions during the Epoch of Reionization (EoR). Previous attempts to express this in terms of a clumping factor, C, typically failed to resolve the full range of mass scales which are important in establishing this effect, down to the Jeans scale in the pre-ionization IGM, along with the hydrodynamical back-reaction of reionization on it. Towards that end, we introduce GADGET-RT, a GADGET code with a new algorithm to transfer H-ionizing radiation, and perform a set of radiation-hydrodynamics simulations from cosmological initial conditions. We extend the mass resolution of previous work to the scale of minihalos, simulating sub-Mpc volumes. Pre-reionization structure is evolved until a redshift $z_i$ at which the ionizing radiation from external sources arrives to sweep an R-type ionization front supersonically across the volume in a few Myr, unt...

  4. X-ray computed tomography investigation of structures in Opalinus Clay from large-scale to small-scale after mechanical testing

    Science.gov (United States)

    Kaufhold, Annette; Halisch, Matthias; Zacher, Gerhard; Kaufhold, Stephan

    2016-08-01

    In the past years X-ray computed tomography (CT) has became more and more common for geoscientific applications and is used from the µm-scale (e.g. for investigations of microfossils or pore-scale structures) up to the dm-scale (full drill cores or soil columns). In this paper we present results from CT imaging and mineralogical investigations of an Opalinus Clay core on different scales and different regions of interest, emphasizing especially the 3-D evaluation and distribution of cracks and their impact on mechanical testing of such material. Enhanced knowledge of the testing behaviour of the Opalinus Clay is of great interest, especially since this material is considered for a long-term radioactive waste disposal and storage facility in Switzerland. Hence, results are compared regarding the mineral (i.e. phase) contrast resolution, the spatial resolution, and the overall scanning speed.With this extensive interdisciplinary scale-down approach it has been possible to characterize the general fracture propagation in comparison to mineralogical and textural features of the Opalinus Clay. Additionally, and as far as we know, a so-called mylonitic zone, located at an intersect of two main fractures, has been observed for the first time for an experimentally deformed Opalinus sample. The multi-scale results are in good accordance to data from naturally deformed Opalinus Clay samples, which enables us to perform systematical research under controlled laboratory conditions. Accompanying 3-D imaging greatly enhances the capability of data interpretation and assessment of such a material.

  5. Small-scale Anisotropies of Cosmic Rays from Relative Diffusion

    Science.gov (United States)

    Ahlers, Markus; Mertsch, Philipp

    2015-12-01

    The arrival directions of multi-TeV cosmic rays show significant anisotropies at small angular scales. It has been argued that this small-scale structure can naturally arise from cosmic ray scattering in local turbulent magnetic fields that distort a global dipole anisotropy set by diffusion. We study this effect in terms of the power spectrum of cosmic ray arrival directions and show that the strength of small-scale anisotropies is related to properties of relative diffusion. We provide a formalism for how these power spectra can be inferred from simulations and motivate a simple analytic extension of the ensemble-averaged diffusion equation that can account for the effect.

  6. Simulating Small-Scale Object Stacking Using Stack Stability

    DEFF Research Database (Denmark)

    Kronborg Thomsen, Kasper; Kraus, Martin

    2015-01-01

    This paper presents an extension system to a closed-source, real-time physics engine for improving structured stacking behavior with small-scale objects such as wooden toy bricks. The proposed system was implemented and evaluated. The tests showed that the system is able to simulate several common...

  7. The Alpha Centauri Binary System: Atmospheric Parameters and Element Abundances

    CERN Document Server

    de Mello, G F Porto; Keller, G R

    2008-01-01

    The Alpha Centauri binary system, owing to its binarity, proximity and brightness, is a fundamental calibrating object for the theory of stellar structure and evolution. This role, however, is hindered by a considerable disagreement in the published analyses of its atmospheric parameters and abundances. We report a detailed spectroscopic analysis of both components of the Alpha Centauri binary system, differentially with respect to the Sun, based on high quality spectra (R = 35 000, S/N > 1000). The atmospheric parameters of the system are found to be Teff = 5820 K, [Fe/H] = +0.24, log g = 4.34 and xi = 1.46 km/s, for Alpha Cen A, and Teff = 5240 K, [Fe/H] = +0.25, log g = 4.44 and xi = 1.28 km/s for Alpha Cen B. The parameters were derived from the simultaneous excitation & ionization equilibria of the equivalent widths of Fe I and Fe II lines, by fitting theoretical profiles to the Halpha line and from photometric calibrations, good agreement being reached between the criteria for both stars. We derived...

  8. Discovery of Small-Scale Spiral Structures in the Disk of SAO 206462 (HD 135344B): Implications for the Physical State of the Disk from Spiral Density Wave Theory

    Science.gov (United States)

    Grady, C. A.; Currie, T.

    2012-01-01

    We present high-resolution, H-band, imaging observations, collected with Subaru/HiCIAO, of the scattered light from the transitional disk around SAO 206462 (HD 135344B). Although previous sub-mm imagery suggested the existence of the dust-depleted cavity at r approximates 46 AU, our observations reveal the presence of scattered light components as close as 0".2 (approx 28 AU) from the star. Moreover, we have discovered two small-scale spiral structures lying within 0".5 (approx 70 AU). We present models for the spiral structures using the spiral density wave theory, and derive a disk aspect ratio of h approx 0.1, which is consistent with previous sub-mm observations. This model can potentially give estimates of the temperature and rotation profiles of the disk based on dynamical processes, independently from sub-mm observations. It also predicts the evolution of the spiral structures, which can be observable on timescales of 10-20 years, providing conclusive tests of the model. While we cannot uniquely identify the origin of these spirals, planets embedded in the disk may be capable of exciting the observed morphology. Assuming that this is the case, we can make predictions on the locations and, possibly, the masses of the unseen planets. Such planets may be detected by future multi-wavelengths observations.

  9. DISCOVERY OF SMALL-SCALE SPIRAL STRUCTURES IN THE DISK OF SAO 206462 (HD 135344B): IMPLICATIONS FOR THE PHYSICAL STATE OF THE DISK FROM SPIRAL DENSITY WAVE THEORY

    International Nuclear Information System (INIS)

    We present high-resolution, H-band imaging observations, collected with Subaru/HiCIAO, of the scattered light from the transitional disk around SAO 206462 (HD 135344B). Although previous sub-mm imagery suggested the existence of a dust-depleted cavity at r ≤ 46 AU, our observations reveal the presence of scattered light components as close as 0.''2 (∼ 28 AU) from the star. Moreover, we have discovered two small-scale spiral structures lying within 0.''5 (∼ 70 AU). We present models for the spiral structures using the spiral density wave theory, and derive a disk aspect ratio of h ∼ 0.1, which is consistent with previous sub-mm observations. This model can potentially give estimates of the temperature and rotation profiles of the disk based on dynamical processes, independently from sub-mm observations. It also predicts the evolution of the spiral structures, which can be observable on timescales of 10-20 years, providing conclusive tests of the model. While we cannot uniquely identify the origin of these spirals, planets embedded in the disk may be capable of exciting the observed morphology. Assuming that this is the case, we can make predictions on the locations and, possibly, the masses of the unseen planets. Such planets may be detected by future multi-wavelength observations.

  10. Appendix - A small scale research review

    DEFF Research Database (Denmark)

    Larsen, Lea Lund

    A small scale research review This appendix provides an analysis of a small scale search for empirical studies regarding the efficacy of adult teacher training. The appendix is a part of a paper delivered at the ASEM conference, June 2009, Bergisch Gladbach, Germany. The paper tries to shed light...... over two questions asked in the abstract concerning workshop C - Effects of teacher training in lifelong learning - at the current ASEM conference. At first it is asked what do we already know about teacher training effects in relation to adult learners? This will be identified by a search for...... systematic reviews in the international This will be identified by a search for systematic reviews in the international clearinghouses and afterwards by a small scale mapping done in the pedagogic databaseERIC. The second question sounds: which methods can be used to measure the effects of teacher...

  11. SMALL SCALE BIOMASS FUELED GAS TURBINE ENGINE

    Science.gov (United States)

    A new generation of small scale (less than 20 MWe) biomass fueled, power plants are being developed based on a gas turbine (Brayton cycle) prime mover. These power plants are expected to increase the efficiency and lower the cost of generating power from fuels such as wood. The n...

  12. Small-scale household biogas digesters

    DEFF Research Database (Denmark)

    Bruun, Sander; Jensen, Lars Stoumann; Khanh Vu, Van Thi;

    2014-01-01

    -scale digesters and their biogas production, this corresponds to methane losses of 4.5 Tg yr -1 or about 1% of global emissions or 10% as much as emissions from rice production. Further poliferation of small-scale digesters could therefore contribute significantly to global emissions of methane. It is therefore...

  13. A Portrait of Cold Gas in Galaxies at 60pc Resolution and a Simple Method to Test Hypotheses That Link Small-Scale ISM Structure to Galaxy-Scale Processes

    CERN Document Server

    Leroy, Adam K; Schruba, Andreas; Rosolowsky, Erik; Blanc, Guillermo; Bolatto, Alberto D; Colombo, Dario; Escala, Andres; Kramer, Carsten; Kruijssen, J M Diederik; Meidt, Sharon; Pety, Jerome; Querejeta, Miguel; Sandstrom, Karin; Schinnerer, Eva; Sliwa, Kazimierz; Usero, Antonio

    2016-01-01

    The cloud-scale density, velocity dispersion, and gravitational boundedness of the interstellar medium (ISM) vary within and among galaxies. In turbulent models, these properties play key roles in the ability of gas to form stars. New high fidelity, high resolution surveys offer the prospect to measure these quantities across galaxies. We present a simple approach to make such measurements and to test hypotheses that link small-scale gas structure to star formation and galactic environment. Our calculations capture the key physics of the Larson scaling relations, and we show good correspondence between our approach and a traditional "cloud properties" treatment. However, we argue that our method is preferable in many cases because of its simple, reproducible characterization of all emission. Using, low-J 12CO data from recent surveys, we characterize the molecular ISM at 60pc resolution in the Antennae, the Large Magellanic Cloud, M31, M33, M51, and M74. We report the distributions of surface density, velocit...

  14. Possibilities of life around Alpha Centauri B

    CERN Document Server

    Gonzalez, Antolin; Hearnshaw, John

    2014-01-01

    We make a preliminary assessment on the habitability of potential rocky exoplanets around Alpha Centauri B. We use several indexes: the Earth Similarity Index, a mathematical model for photosynthesis, and a biological productivity model. Considering the atmospheres of the exoplanets similar to current Earth's atmosphere, we find consistent predictions of both the Earth Similarity Index and the biological productivity model. The mathematical model for photosynthesis clearly failed because does not consider the temperature explicitly. For the case of Alpha Centauri B, several simulation runs give 11 planets in the habitable zone. Applying to them above mentioned indexes, we select the five exoplanets more prone for photosynthetic life; showing that two of them in principle have better conditions than Earth for this kind of life.

  15. Small-scale anisotropies of cosmic rays from relative diffusion

    CERN Document Server

    Mertsch, Philipp

    2015-01-01

    The arrival directions of multi-TeV cosmic rays show significant anisotropies at small angular scales. It has been argued that this small scale structure is reflecting the local, turbulent magnetic field in the presence of a global dipole anisotropy in cosmic rays as determined by diffusion. This effect is analogous to weak gravitational lensing of temperature fluctuations of the cosmic microwave background. We show that the non-trivial power spectrum in this setup can be related to the properties of relative diffusion and we study the convergence of the angular power spectrum to a steady-state as a function of backtracking time. We also determine the steady-state solution in an analytical approach based on a modified BGK ansatz. A rigorous mathematical treatment of the generation of small scale anisotropies will help in unraveling the structure of the local magnetic field through cosmic ray anisotropies.

  16. Economy of small-scale power plants

    International Nuclear Information System (INIS)

    The basic requirement for profitable generation of power and heat is sufficient and even heat load. The investment required by a plant based on cogeneration is always higher than that of a plant producing only heat, and hence the full time operation of the plant should be ensured since the beginning of the plant operational age. The second requirement for profitable operation of a small-scale power plant is the homogenous heat and power consumption profiles. Because the plants always cause remarkable capital costs and other fixed costs it is important to make an economic survey of the costs before the decision making in the preliminary planning phase. The presentation gives a review of the factors effecting on the economy of small-scale power plant, the distribution of the costs, and the methods used for investigation of the economy are reviewed

  17. Small-Scale Wind Turbines: an Appraisal

    OpenAIRE

    Kealy, Tony

    2013-01-01

    This research seeks to evaluate the economic benefits to be gained by installing a small-scale wind turbine for a customer with a three-phase electrical supply requirement. The evidence for the claims made in this paper is obtained by using actual data obtained from the installed equipment over a three year period. The objective is to accurately appraise the financial investment using real data. There appears to be limited studies conducted into this type of research, possibly because the ren...

  18. Symmetry breaking and synchronization at small scales

    OpenAIRE

    Elfring, Gwynn J.

    2012-01-01

    This thesis is devoted to the theoretical description of two experimentally observed phenomena which occur at small scales. We first address the synchronization of swimming microorganisms. Motile microorganisms swim in a fluid regime where inertia is unimportant and viscous stresses dominate. In this limit the flow field due to a swimmer affects the motility of nearby cells, a fact which is biologically important as microorganisms such as spermatozoa are often found in high-density suspension...

  19. Regulatory enclosures: small scale women livestock farmers

    OpenAIRE

    McMahon, Martha

    2008-01-01

    "There are efforts by a variety of social movements and civil society organizations to encourage the development of alternative agri-food networks that are socially just, ecological, humane and which ensure food security and food sovereignty. Many activists focus their critiques on the role of large multinational corporations in restructuring and globalizing the agri-food system. They offer in its place a vision of locally oriented, small scale ecological farming. Drawing on th...

  20. Small-scale forestry in Sweden

    OpenAIRE

    Ingemarson, Fredrik

    2004-01-01

    The purpose of the thesis was to improve the tools for decision making for small-scale forest owners in Sweden. Understanding the objectives of forest owners is crucial for the success of policy initiatives and for promoting successful sustainable forest management. The aims of this thesis were to: a) depict the green forest management plan from a nature conservation point of view; b) identify objectives of owners’; c) analyse different types of owners; and d) evaluate the suitability of silv...

  1. Dislocation dynamics simulations of plasticity at small scales

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Caizhi

    2010-12-15

    As metallic structures and devices are being created on a dimension comparable to the length scales of the underlying dislocation microstructures, the mechanical properties of them change drastically. Since such small structures are increasingly common in modern technologies, there is an emergent need to understand the critical roles of elasticity, plasticity, and fracture in small structures. Dislocation dynamics (DD) simulations, in which the dislocations are the simulated entities, offer a way to extend length scales beyond those of atomistic simulations and the results from DD simulations can be directly compared with the micromechanical tests. The primary objective of this research is to use 3-D DD simulations to study the plastic deformation of nano- and micro-scale materials and understand the correlation between dislocation motion, interactions and the mechanical response. Specifically, to identify what critical events (i.e., dislocation multiplication, cross-slip, storage, nucleation, junction and dipole formation, pinning etc.) determine the deformation response and how these change from bulk behavior as the system decreases in size and correlate and improve our current knowledge of bulk plasticity with the knowledge gained from the direct observations of small-scale plasticity. Our simulation results on single crystal micropillars and polycrystalline thin films can march the experiment results well and capture the essential features in small-scale plasticity. Furthermore, several simple and accurate models have been developed following our simulation results and can reasonably predict the plastic behavior of small scale materials.

  2. Small-scale hydro power in Finland

    International Nuclear Information System (INIS)

    At present there are around 150 operating small-scale hydro power plants in Finland, the power generating capacity of which varies between 50 and 1000 kW. The annual output in terms of produced energy is about 270 GWh which accounts for only 0.5 % of the total consumption of electricity. The plants are mainly owned by electricity distributing companies and industry. There are numerous old dams and abandoned small hydro power stations, once used as power source for flour mills and saw mills. The role of overall energy economics is reviewed in this article, as well as the increase potential for small-scale hydro power and the international cooperation in this field. The potential for small-scale hydro power in Finland has been estimated to be 370 MW in 1580 falls, of which 45 MW is used at 150 stations. Easily exploitable sites, usually with abandoned station or dam were calculated to be around 80 MW, corresponding to an annual energy output at 350 GWh

  3. Handling of Small-Scale Protests in China

    DEFF Research Database (Denmark)

    Gui, Xiaowei

    The dissertation examines the dynamics and outcomes of small-scale protests in China by more meticulously scrutinizing the role of the state. In order to clarify the sensitive topic of how local officials and protesters try to outmaneuver each other, I have conducted an in-depth fieldwork that is...... thesis in which I primarily explain how and why the study is conducted in four different fields, viz. China studies, political science, sociology and anthropology. Chapter Two is theoretical core of the dissertation. Based on a comprehensive literature review, the chapter redirects our attention away...... from protesters and towards officials, and develops a framework to more meticulously scrutinize the role of the state, in order to better explain the fate of small-scale protests in China. Chapter Three covers the methodological aspects of the dissertation. I describe how I structured my fieldwork and...

  4. Small-Scale Hydroelectric Power Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Gleeson, L.

    1991-12-01

    The US Department of Energy Field Office, Idaho, Small-Scale Hydroelectric Power Program was initiated in conjunction with the restoration of three power generating plants in Idaho Falls, Idaho, following damage caused by the Teton Dam failure on June 5, 1976. There were many parties interested in this project, including the state and environmental groups, with different concerns. This report was prepared by the developer and describes the design alternatives the applicant provided in an attempt to secure the Federal Energy Regulatory Commission license. Also included are correspondence between the related parties concerning the project, major design alternatives/project plan diagrams, the license, and energy and project economics.

  5. A new spatially scanning 2.7 µm laser hygrometer and new small-scale wind tunnel for direct analysis of the H2O boundary layer structure at single plant leaves

    Science.gov (United States)

    Wunderle, K.; Rascher, U.; Pieruschka, R.; Schurr, U.; Ebert, V.

    2015-01-01

    A new spatially scanning TDLAS in situ hygrometer based on a 2.7-µm DFB diode laser was constructed and used to analyse the water vapour concentration boundary layer structure at the surface of a single plant leaf. Using an absorption length of only 5.4 cm, the TDLAS hygrometer permits a H2O vapour concentration resolution of 31 ppmv. This corresponds to a normalized precision of 1.7 ppm m. In order to preserve and control the H2O boundary layer on an individual leaf and to study the boundary layer dependence on the wind speed to which the leaf might be exposed in nature, we also constructed a new, application specific, small-scale, wind tunnel for individual plant leaves. The rectangular, closed-loop tunnel has overall dimensions of 1.2 × 0.6 m and a measurement chamber dimension of 40 × 54 mm (H × W). It allows to generate a laminar flow with a precisely controlled wind speed at the plant leaf surface. Combining honeycombs and a miniaturized compression orifice, we could generate and control stable wind speeds from 0.1 to 0.9 m/s, and a highly laminar and homogeneous flow with an excellent relative spatial homogeneity of 0.969 ± 0.03. Combining the spectrometer and the wind tunnel, we analysed (for the first time) non-invasively the wind speed-dependent vertical structure of the H2O vapour distribution within the boundary layer of a single plant leaf. Using our time-lag-free data acquisition procedure for phase locked signal averaging, we achieved a temporal resolution of 0.2 s for an individual spatial point, while a complete vertical spatial scan at a spatial resolution of 0.18 mm took 77 s. The boundary layer thickness was found to decrease from 6.7 to 3.6 mm at increasing wind speeds of 0.1-0.9 m/s. According to our knowledge, this is the first experimental quantification of wind speed-dependent H2O vapour boundary layer concentration profiles of single plant leaves.

  6. Adopting small-scale production of electricity

    Energy Technology Data Exchange (ETDEWEB)

    Tengvard, Maria; Palm, Jenny (Linkoeping Univ., Dept. of Technology and Social Change, Linkoeping (Sweden)). e-mail: maria.tengvard@liu.se

    2009-07-01

    In Sweden in 2008, a 'new' concept for small-scale electricity production attracted massive media attention. This was mainly due to the efforts of Swedish company Egen El, which is marketing small-scale photovoltaics (PVs) and wind turbines to households, both homeowners and tenants. Their main selling point is simplicity: their products are so easy to install that everyone can do it. Autumn 2008 also saw IKEA announce that within three years it would market solar panels. How, then, do households perceive these products? Why would households choose to buy them? How do households think about producing their own electricity? Analysis of material based on in-depth interviews with members of 20 households reveals that environmental concerns supply the main motive for adopting PVs or micro wind power generation. In some cases, the adopting households have an extensively ecological lifestyle and such adoption represents a way to take action in the energy area. For some, this investment is symbolic: a way of displaying environmental consciousness or setting an example to others. For still others, the adoption is a protest against 'the system' with its large dominant actors or is a way to become self-sufficient. These microgeneration installations are rejected mainly on economic grounds; other motives are respect for neighbours and difficulties finding a place to install a wind turbine.

  7. Profitability of small-scale power plants

    International Nuclear Information System (INIS)

    Several small-scale power plants have been constructed in Finland during the last few years. Fuel oil and natural gas has been used as a fuel in diesel plants, natural gas in gas-turbine plants, and peat and industrial waste wood in solid fuel fired plants. Larger towns have already acquired combined power and heat generation either in their own power plants or in cooperation with industry. A usual mean of cooperation has been buying of district heat from industrial back-pressure power plants. Numerous small district heat loads still rely on separate heat production. The cheap price of electric power, caused by the good water and nuclear power conditions and long-term delivery contracts, has rendered the construction of small-scale power plants. The fuel prices have been stable for the last few years. The most significant changes have been caused by changing of exchange rate of the Finnish mark and the fuel taxation. Two power plant are reviewed in detail: 6/17 MW peat fired steam power plant and 6/6 MW oil fueled diesel power plant. The electricity prices of these two have been compared with coal condensing power and the electricity tariffs. The price comparisons have been made using the present price level. Energia-Ekono has compiled a new simulation program ELMO, operating in PC-WINDOWS environment, for simulation of cogeneration

  8. Small-scale fisheries in Greenlandic planning

    DEFF Research Database (Denmark)

    Jacobsen, Rikke Becker

    2013-01-01

    coastal fishery for Greenland halibut’. Findings highlight the way the small-scale Greenland halibut fishery system becomes a particular governance problem with respect to particular contextual meanings of sustainability and long-term planning. The article then examines whether this governance problem......This article analyses an ongoing planning process in Greenlandic fisheries governance aiming to reform the coastal Greenland halibut fishery. It examines the way certain truths about this fishery and the need for reform are produced up to and in the final policy document ‘regulation concerning the...... could also be understood as primarily a problem to a certain ‘governmentality’ mode of governance. Whereas some fishery studies document how governmentality modes of governance in fisheries succeeds in transforming subjectivities, this study offers a view into the process that might go before successful...

  9. New markets for small-scale hydro

    International Nuclear Information System (INIS)

    The market for small and medium sized hydro-electric power plant is more attractive than ever. The boom in Europe has increasingly spread to the emerging countries, and here too small hydro plays an important ecological role. In addition to new plant rehabilitation of 'historical' plant is now a major factor. The last few years have seen a market shift from single machine components to complete plant and systems, requiring a strategy re-think on the part of larger companies. Following the influx of private capital into the power industry, business conditions have also undergone a thorough transformation. In place of 'fast money', hydro power offers the prospect of earning longer-term, sustainable money'. The term small-scale hydro-electric power (or simply 'small hydro') is used slightly differently depending on the country and market. Here, it is used to denote plant with turbines up to 10 MW. (Author)

  10. Commentary: Let’s send the DOE to Alpha Centauri

    OpenAIRE

    Kite, Edwin; Howard, Andrew

    2013-01-01

    The announcement of an Earth-mass planet orbiting the closest Sunlike star has renewed discussion of the costs and benefits of an interstellar probe. The planet, Alpha Centauri Bb, is in an extremely hot orbit, but its existence increases the probability that a planet with a liquid-water ocean orbits Alpha Centauri. Data from NASA’s Kepler telescope now show that there are about as many habitable-zone, Earth-sized planets as stars, and in April NASA decided...

  11. Overview of the Testing of a Small-Scale Proprotor

    Science.gov (United States)

    Young, Larry A.; Yamauchi, Gloria K.; Booth, Earl R., Jr.; Botha, Gavin; Dawson, Seth

    1999-01-01

    This paper presents an overview of results from the wind tunnel test of a 1/4-scale V-22 proprotor in the Duits-Nederlandse Windtunnel (DNW) in The Netherlands. The small-scale proprotor was tested on the isolated rotor configuration of the Tilt Rotor Aeroacoustic Model (TRAM). The test was conducted by a joint team from NASA Ames, NASA Langley, U.S. Army Aeroflightdynamics Directorate, and The Boeing Company. The objective of the test was to acquire a benchmark database for validating aeroacoustic analyses. Representative examples of airloads, acoustics, structural loads, and performance data are provided and discussed.

  12. Water power small scale hydro. Elan Valley

    International Nuclear Information System (INIS)

    The Elan Valley small-scale hydro project, which is owned and operated by Hyder Industrial Ltd, is located on the Elan Valley estate in the Cambrian Mountains in mid-Wales. Five reservoirs and four impounding dams were built in the Elan and Claerwen river valleys during the first half of the 20th century to supply water to Birmingham. Following the award of a contract under the Government's third non-Fossil Fuel Obligation Order (NFFO-3) to supply 4.2 MW of electricity to the National Grid during the 1990s, Hyder refurbished the original turbines at one location and built new units at four others. The existing water infrastructure was utilised. The total cost of the scheme, which generated some 35,700 MWh of electricity between May 1997 and March 1999, was 5.2 million pounds sterling. Details of the power generation units at the five hydro power stations, the power output, power transmission, planning requirements, measures taken by Hyder to minimise the scheme's environmental impact and the scheme's benefits are given

  13. Small-scale irradiated fuel electrorefining

    International Nuclear Information System (INIS)

    In support of the metallic fuel cycle development for the Integral Fast Reactor (IFR), a small scale electrorefiner was built and operated in the Hot Fuel Examination Facility (HFEF) at Argonne National Laboratory-West. The initial purpose of this apparatus was to test the single segment dissolution of irradiated metallic fuel via either direct dissolution in cadmium or anodic dissolution. These tests showed that 99.95% of the uranium and 99.99% of the plutonium was dissolved and separated from the fuel cladding material. The fate of various fission products was also measured. After the dissolution experiments, the apparatus was upgraded to stady fission product behavior during uranium electrotransport. Preliminary decontamination factors were estimated for different fission products under different processing conditions. Later modifications have added the following capabilities: Dissolution of multiple fuel segments simultaneously, electrotransport to a solid cathode or liquid cathode and actinide recovery with a chemical reduction crucible. These capabilities have been tested with unirradiated uranium-zirconium fuel and will support the Fuel Cycle Demonstration program

  14. Small-scale mechanical behavior of zirconia

    International Nuclear Information System (INIS)

    Graphical abstract: - Abstract: The surface stability of yttria-doped tetragonal polycrystalline zirconia is critical for load-bearing biomedical applications. In this work, the small-scale mechanical behavior of this material is probed by employing the in situ micro-cantilever bending technique to near-surface regions. Micro-cantilevers are milled by the focused ion beam technique in the as-sintered condition as well as after hydrothermal degradation by water vapor and tested in order to investigate the effect of degradation on the local flexural response. Results demonstrate that the technique is reliable for assessing the mechanical properties of thin superficial layers and their dependence on orientation. In the non-degraded material, the flexural strength is surprisingly higher than in standard-size specimens and transformation-induced plasticity takes place during testing, inducing defects that become critical at the failure stress. The strength and stiffness of cantilevers obtained from the degraded surface are indeed much lower, and the magnitude of the effect clearly depends on their orientation with respect to the surface. These results are discussed in terms of the presence and spatial distribution of microcracks nucleated during hydrothermal degradation

  15. Small Scale Variations in Carbon Oxygen Ratio

    International Nuclear Information System (INIS)

    The aim of the research reported here is the development of a methodology for the measurement of small scale variations in chemical elements concentrations, in particular of carbon - oxygen ratio. Knowledge of the C/O ratio is of importance to many problems in various fields. Here we single out the application in obtaining important information about the oil fields. The most fundamental reservoir parameters - oil, gas and water content - are critical factors in determining how each oil field should be developed. It is well established that carbon to oxygen ratio log yields accurate and repeatable data that can be used to identify and monitor reserves depletion. Recent improvements in neutron generator and gamma detector technologies resulted in small devices which allowed through-tubing measurements. Although the ratio of carbon and oxygen yields is a measure of the amount of oil around the tool it should be realized that a carbon signal can originate from several sources including the borehole, the cement behind the casing, the formation rock and the formation fluid. In order to evaluate these contributions individually we are proposing the modification of the neutron generator by insertion of segmented associated alpha particle detector. From the measurement of time of flight spectra (alpha particle detector - start signal; gamma ray detector - stop signal) it would be possible to determine the location of gamma ray producing voxel and in such a way to determine radial variations in several chemical elements concentrations, in particular of carbon to oxygen ratio. (authors)

  16. Galaxy alignment on large and small scales

    CERN Document Server

    Kang, X; Wang, Y O; Dutton, A; Macciò, A

    2014-01-01

    Galaxies are not randomly distributed across the universe but showing different kinds of alignment on different scales. On small scales satellite galaxies have a tendency to distribute along the major axis of the central galaxy, with dependence on galaxy properties that both red satellites and centrals have stronger alignment than their blue counterparts. On large scales, it is found that the major axes of Luminous Red Galaxies (LRGs) have correlation up to 30Mpc/h. Using hydro-dynamical simulation with star formation, we investigate the origin of galaxy alignment on different scales. It is found that most red satellite galaxies stay in the inner region of dark matter halo inside which the shape of central galaxy is well aligned with the dark matter distribution. Red centrals have stronger alignment than blue ones as they live in massive haloes and the central galaxy-halo alignment increases with halo mass. On large scales, the alignment of LRGs is also from the galaxy-halo shape correlation, but with some ex...

  17. Hall-magnetohydrodynamic small-scale dynamos.

    Science.gov (United States)

    Gómez, Daniel O; Mininni, Pablo D; Dmitruk, Pablo

    2010-09-01

    Magnetic field generation by dynamo action is often studied within the theoretical framework of magnetohydrodynamics (MHD). However, for sufficiently diffuse media, the Hall effect may become non-negligible. We present results from three-dimensional simulations of the Hall-MHD equations subjected to random nonhelical forcing. We study the role of the Hall effect in the dynamo efficiency for different values of the Hall parameter. For small values of the Hall parameter, the small-scale dynamo is more efficient, displaying faster growth and saturating at larger amplitudes of the magnetic field. For larger values of the Hall parameter, saturation of the magnetic field is reached at smaller amplitudes than in the MHD case. We also study energy transfer rates among spatial scales and show that the Hall effect produces a reduction of the direct energy cascade at scales larger than the Hall scale, therefore leading to smaller energy dissipation rates. Finally, we present results stemming from simulations at large magnetic Prandtl numbers, which is the relevant regime in the hot and diffuse interstellar medium. In the range of magnetic Prandtl numbers considered, the Hall effect moves the peak of the magnetic energy spectrum as well as other relevant magnetic length scales toward the Hall scale. PMID:21230195

  18. The Ups and Downs of Alpha Centauri

    Science.gov (United States)

    Ayres, Thomas

    2014-11-01

    Nearby Alpha Centauri is destined for a pivotal chapter in human history, as first stop of future starfarers from Earth: 3x closer than the next nearest star; three very different objects to visit -- Alpha Cen A (G2V), B (K1V), and C (M6V); and B hosts an Earth-mass companion, albeit in a hot, lifeless orbit. For its part, Chandra has been keeping intent watch on the high-energy starspot cycles of AB, with semi-annual pointings over the past decade. Only HRC-I can separate AB as they plunge toward a close approach of 4" in 2016; and LETGS has countered that an abrupt 50x drop in XMM count rate of sun-like A in early 2005, ominously reported as the "darkening of the solar twin," simply is a soft sensitivity issue, not an unprecedented, inexplicable case of corona interrupta.

  19. Geomagnetic properties of Proxima Centauri b analogues

    CERN Document Server

    Zuluaga, Jorge I

    2016-01-01

    The recent discovery of a planet around the closest star, Proxima Centauri, could represent a quantum leap on the testability of models in exoplanet sciences. Unlike any other discovered exoplanet, models of planetary processes in Proxima b could be contrasted against near future telescopic observations and far future in-situ measurements. In this paper we study the geomagnetic properties of Proxima b analogues, namely, solid planets with masses close but larger than Earth's mass, periods of rotation of several days and habitable surface conditions. Assuming different planetary masses, bulk compositions and periods of rotations, we calculate for each planetary analogue its radius, heat flux, time of inner core formation, dynamo lifetime and minimum dipole magnetic moment. We find that most ($\\gtrsim$70\\%) Proxima b analogues develop intrinsic dynamos that last at least 3 Gyr, although only half of them are older than the present age of the host star ($4-6$ Gyr). Relying in our planetary evolution models, we p...

  20. Small scale imaging using ultrasonic tomography

    International Nuclear Information System (INIS)

    Ultrasound technology progressed through the 1960 from simple A-mode and B-mode scans to today M-mode and Doppler two dimensional (2-D) and even three dimensional (3-D) systems. Modern ultrasound imaging has its roots in sonar technology after it was first described by Lord John Rayleigh over 100 years ago on the interaction of acoustic waves with media. Tomography technique was developed as a diagnostic tool in the medical area since the early of 1970s. This research initially focused on how to retrieve a cross sectional images from living and non-living things. After a decade, the application of tomography systems span into the industrial area. However, the long exposure time of medical radiation-based method cannot tolerate the dynamic changes in industrial process two phase liquid/ gas flow system. An alternative system such as a process tomography systems, can give information on the nature of the flow regime characteristic. The overall aim of this paper is to investigate the use of a small scale ultrasonic tomography method based on ultrasonic transmission mode tomography for online monitoring of liquid/ gas flow in pipe/ vessel system through ultrasonic transceivers application. This non-invasive technique applied sixteen transceivers as the sensing elements to cover the pipe/ vessel cross section. The paper also details the transceivers selection criteria, hardware setup, the electronic measurement circuit and also the image reconstruction algorithm applied. The system was found capable of visualizing the internal characteristics and provides the concentration profile for the corresponding liquid and gas phases. (author)

  1. Small-Scale CMOS Pseudo SRAM Module Design

    Institute of Scientific and Technical Information of China (English)

    李昀; 刘振宇; 韩月秋

    2004-01-01

    An approach to design small scale CMOS static random access memory (SRAM) is proposed. The design of address decoder, memory cell, and the layout are included. This approach adopts flip-flop array structure. The flip-flops are used as the storage cells and they are stacked to form the whole SRAM module. The word select bit is generated from the address decoder. And one word at a time is selected for reading or writing. The design of the memory core's layout is also discussed since it should be optimized to save area and also should be convenient for realization. It's a full-custom layout. The address decoder is composed of combinational logic circuit and its layout is also designed as a full-custom layout. With all these modules, the integral structure of the SRAM is carried out.

  2. Cosmic Ray Small Scale Anisotropies and Local Turbulent Magnetic Fields

    CERN Document Server

    López-Barquero, Vanessa; Xu, S; Desiati, P; Lazarian, A

    2015-01-01

    Cosmic ray anisotropy is observed in a wide energy range and at different angular scales by a variety of experiments. However, a comprehensive and satisfactory explanation has been elusive for over a decade now. The arrival distribution of cosmic rays on Earth is the convolution of the distribution of their sources and of the effects of geometry and properties of the magnetic field through which particles propagate. It is generally believed that the anisotropy topology at the largest angular scale is adiabatically shaped by diffusion in the structured interstellar magnetic field. On the contrary, the medium and small angular scale structure could be an effect of non diffusive propagation of cosmic rays in perturbed magnetic fields. In particular, a possible explanation of the observed small scale anisotropy observed at TeV energy scale, may come from the effect of particle scattering in turbulent magnetized plasmas. We perform numerical integration of test particle trajectories in low-$\\beta$ compressible mag...

  3. A multi scale model for small scale plasticity

    International Nuclear Information System (INIS)

    Full text.A framework for investigating size-dependent small-scale plasticity phenomena and related material instabilities at various length scales ranging from the nano-microscale to the mesoscale is presented. The model is based on fundamental physical laws that govern dislocation motion and their interaction with various defects and interfaces. Particularly, a multi-scale model is developed merging two scales, the nano-microscale where plasticity is determined by explicit three-dimensional dislocation dynamics analysis providing the material length-scale, and the continuum scale where energy transport is based on basic continuum mechanics laws. The result is a hybrid simulation model coupling discrete dislocation dynamics with finite element analyses. With this hybrid approach, one can address complex size-dependent problems, including dislocation boundaries, dislocations in heterogeneous structures, dislocation interaction with interfaces and associated shape changes and lattice rotations, as well as deformation in nano-structured materials, localized deformation and shear band

  4. Small-Scale Fisheries Bycatch Jeopardizes Endangered Pacific Loggerhead Turtles

    OpenAIRE

    Peckham, S. Hoyt; Diaz, David Maldonado; Walli, Andreas; Ruiz, Georgita; Larry B. Crowder; Nichols, Wallace J.

    2007-01-01

    Background Although bycatch of industrial-scale fisheries can cause declines in migratory megafauna including seabirds, marine mammals, and sea turtles, the impacts of small-scale fisheries have been largely overlooked. Small-scale fisheries occur in coastal waters worldwide, employing over 99% of the world's 51 million fishers. New telemetry data reveal that migratory megafauna frequent coastal habitats well within the range of small-scale fisheries, potentially producing high bycatch. These...

  5. Characteristic of Small Scale Food Industry Cluster in West Sumatera

    OpenAIRE

    Gunarif Taib; Santosa Santosa; Masrul Djalal; Helmi Helmi

    2014-01-01

    Clusters of small-scale food industries have different characteristics with industrial cluster in general. These characteristics need to know to develop a plan for cluster development. This study was conducted to determine charasteristics clusters of small-scale food industry, especially in West Sumatra. For the analysis of the components of industrial and technological components that affect the development of small-scale food industry cluster in West Sumatra. All variables influence the lev...

  6. MOST Observations of our Nearest Neighbor: Flares on Proxima Centauri

    CERN Document Server

    Davenport, James R A; Sasselov, Dimitar; Matthews, Jaymie M; Cameron, Chris

    2016-01-01

    We present a study of white light flares from the active M5.5 dwarf Proxima Centauri using the Canadian microsatellite MOST. Using 37.6 days of monitoring data from 2014 and 2015, we have detected 66 individual flare events, the largest number of white light flares observed to date on Proxima Cen. Flare energies in our sample range from $10^{29}$-$10^{31.5}$ erg, with complex, multi-peaked structure found in 22% of these events. The flare rate is lower than that of other classic flare stars of similar spectral type, such as UV Ceti, which may indicate Proxima Cen had a higher flare rate in its youth. Proxima Cen does have an unusually high flare rate given the slow reported rotation period, however. Extending the observed power-law occurrence distribution down to $10^{28}$ erg, we show that flares with flux amplitudes of 0.5% occur 63 times per day, while superflares with energies of $10^{33}$ erg occur ~8 times per year. Small flares may therefore pose a great difficulty in searches for transits from the rec...

  7. Small scale BWR core debris eutectics formation and melting experiment

    International Nuclear Information System (INIS)

    A small scale experiment has recently been performed at Oak Ridge under the auspices of the BWR Severe Accident Technology (BWRSAT) program to provide information concerning the formation of mixtures during heatup of representative BWR reactor vessel bottom head debris and to determine the composition and melting temperatures of these mixtures. The initial structure of the bottom head debris layers modeled in the experiment was taken from the results of recent BWR Accident Response (BWRSAR) code predictions for the short-term station blackout accident sequence. The experimental results provide useful information concerning the mixtures formed and their proportions and properties. The observed run-off of a stainless steel-zirconium eutectic alloy supports the contention that the initial pour from a BWR reactor vessel would consists of molten metals at relatively low temperatures. (orig.)

  8. The (Historical) Search for Planets Orbiting Proxima Centauri

    Science.gov (United States)

    Kohler, Susanna

    2016-08-01

    The European Southern Observatory (ESO) is widely expected to address the reportsofthe discovery of a planet orbiting our nearest stellar neighbor, Proxima Centauri, today. Due to its proximity 4.25 light-years away this red dwarf star has been a prime target for exoplanet searches throughout the last couple decades.Hubble image of Proxima Centauri, our nearest stellar neighbor. [ESA/Hubble]In anticipation of ESOspress conference this afternoon, lets take a look at someof the past work in the search for planetary companions around Proxima Centauri.The Early Years of Exploring Proxima CentauriProxima Centauri was discovered by astronomer Robert Innes in 1915. Studies of this star over the next eighty years primarily focused on better understanding its orbital motion (is it part of the Alpha Centauri star system?) and its flaring nature. But in the 1990s, after the detection of the first exoplanets, Proxima Centauri became a target for its potential to host planet-mass companions.Top: Images of Proxima Centauri on two different days from Hubbles FOS instrument. The bar across the center is an occulter that partially blocks the light from Proxima Centauri. Middle: Reconstructed images allowing a closer look at a moving feature identified by the authors as a possible companion. Bottom: diagram of the position of the planet candidate (box) relative to Proxima Centauri (star) in the two frames. [Schultz et al. 1998]1990s: A Possible Planet Detected With Hubble?In January 1998, a paper led by A.B. Schultz (STScI) reported the possible visual detection of a planetary companion to Proxima Centauri. Observations from Hubbles Faint Object Spectrograph, which was being used as a coronagraphic camera, revealed excess light that could be interpreted as a substellar object located ~0.5 AU from Proxima Centauri, a small separation that could imply either a short (~1 yr) period or a highly eccentric orbit.But follow-up observations led by David Golimowski (Johns Hopkins University

  9. Electricity generating costs in small-scale dispersed energy sources

    International Nuclear Information System (INIS)

    Small-scale dispersed energy sources - small-scale-gas-fired cogeneration heat and power (CHP) plants, fuel cells, wind generators and others are playing bigger and bigger role in the world's electricity production. These sources will be not an alternative for the electricity supply system (including nuclear power plants), during the nearest two decades. (author)

  10. Small-Scale Farming: A Portrait from Polk County, Oregon.

    Science.gov (United States)

    Young, John A.; Caday, Peter

    A study of small-scale farmers in Polk County, Oregon, examined characteristics of, and variations among, small-scale farmers and developed some guidelines for assistance programs targeted for such a group. During the months of May, June, and July of 1978 an average of 4 days a week was spent locating and interviewing 44 small farm operators in…

  11. Parallax and masses of α Centauri revisited

    Science.gov (United States)

    Pourbaix, Dimitri; Boffin, Henri M. J.

    2016-02-01

    Context. Despite the thorough work of van Leeuwen, the parallax of α Centauri is still far from being carved in stone. Any derivation of the individual masses is therefore uncertain, if not questionable. And yet, that does not prevent this system from being used for calibration purpose in several studies. Aims: We aim for more accurate model-free parallax and individual masses of this system. Methods: With HARPS, the radial velocities are not only precise but also accurate. Ten years of HARPS data are enough to derive the complement of the visual orbit for a full 3D orbit of α Cen. Results: We locate α Cen (743 mas) right where Hipparcos had originally put it, i.e. slightly farther away than derived by Söderhjelm. The components are thus a bit more massive than previously thought (1.13 and 0.97 M⊙ for A and B, respectively). These values are now in excellent agreement with the latest asteroseismologic results. Based on data obtained from the ESO Science Archive Facility under request numbers HBOFFIN/190700, Pourbaix/192287, Pourbaix/192364, Pourbaix/192404, Pourbaix/192552, Pourbaix/ 192630, and Pourbaix/199124.

  12. Responding to the challenge of artisanal and small-scale mining. How can knowledge networks help?

    Energy Technology Data Exchange (ETDEWEB)

    Buxton, Abbi

    2013-02-15

    This paper reviews what is known about the problems and structural challenges facing the 20-30 million artisanal and small-scale miners and their communities worldwide. Better understanding of these structural challenges is needed to improve policies and policy implementation to further sustainable development opportunities for the sector. The paper explores the current gaps in knowledge to achieve policy change from researchers, practitioners and artisanal and small-scale miners themselves. It explores how a 'knowledge intermediary', which acts to link knowledge with policy, could address these gaps and includes case studies of IIED’s work on knowledge networks and programmes. The paper concludes by proposing a way forward for designing a knowledge programme to meet the particular needs of the artisanal and small-scale mining (ASM) sector, and by inviting ASM sector stakeholders to share their views on the options outlined.

  13. Magnesium Isotope Ratios in omega Centauri Red Giants

    CERN Document Server

    Da Costa, G S; Yong, David

    2013-01-01

    We have used high resolution observations obtained at the AAT with UHRF (R ~ 100,000) and at Gemini-S with b-HROS (R ~ 150,000) to determine magnesium isotope ratios for seven omega Centauri red giants that cover a range in iron abundance from [Fe/H] = --1.78 to --0.78 dex, and for two red giants in M4 (NGC 6121). The omega Centauri stars sample both the "primordial" (i.e., O-rich, Na and Al-poor) and the "extreme" (O-depleted, Na and Al-rich) populations in the cluster. The primordial population stars in both omega Centauri and M4 show (25Mg, 26Mg)/24 Mg isotopic ratios that are consistent with those found for the primordial population in other globular clusters with similar [Fe/H] values. The isotopic ratios for the omega Centauri extreme stars are also consistent with those for extreme population stars in other clusters. The results for the extreme population stars studied indicate that the 26Mg/24Mg ratio is highest at intermediate metallicities ([Fe/H] < --1.4 dex), and for the highest [Al/Fe] values....

  14. On the habitability of exoplanets orbiting Proxima Centauri

    CERN Document Server

    Lopez, Madeleine; Rodriguez, Lien

    2014-01-01

    We apply a mathematical model for photosynthesis to quantitatively assess the habitability of a hypothetical planet orbiting Proxima Centauri, inside the so called habitability zone. Results suggest significant viability for primary biological productivity, provided living organisms have evolved to reach the ability of using infrared light for photosynthesis.

  15. The Habitability of Proxima Centauri b I: Evolutionary Scenarios

    CERN Document Server

    Barnes, Rory; Luger, Rodrigo; Driscoll, Peter E; Quinn, Thomas R; Fleming, David P; Guyer, Benjamin; McDonald, Diego V; Meadows, Victoria S; Arney, Giada; Crisp, David; Domagal-Goldman, Shawn D; Lincowski, Andrew; Lustig-Yaeger, Jacob; Schwieterman, Eddie

    2016-01-01

    We analyze the evolution of the potentially habitable planet Proxima Centauri b to identify environmental factors that affect its long-term habitability. We consider physical processes acting on size scales ranging between the galactic scale, the scale of the stellar system, and the scale of the planet's core. We find that there is a significant probability that Proxima Centauri has had encounters with its companion stars, Alpha Centauri A and B, that are close enough to destabilize Proxima Centauri's planetary system. If the system has an additional planet, as suggested by the discovery data, then it may perturb planet b's eccentricity and inclination, possibly driving those parameters to non-zero values, even in the presence of strong tidal damping. We also model the internal evolution of the planet, evaluating the roles of different radiogenic abundances and tidal heating and find that a planet with chondritic abundance may not generate a magnetic field, but all other models do maintain a magnetic field. W...

  16. Small scale LNG in Madeira Island

    International Nuclear Information System (INIS)

    The presentation addresses the development of LNG supplies to Madeira island and maintains that it will contribute to the replacement of oil products with natural gas for energy supply and transportation, industrial and building sectors and to the development of new concepts and technology for improved efficiency of combined production of electricity, heating and cooling. Some geographical, structural, technological, environmental and energy conservation aspects are discussed

  17. Evaluation of Small-Scale Laterally Loaded Monopiles in Sand

    DEFF Research Database (Denmark)

    Roesen, Hanne Ravn; Thomassen, Kristina; Ibsen, Lars Bo;

    2011-01-01

    from six small-scale laboratory tests, numerical modelling of the same test setup and existing theory. From the numerical models, p−y curves are derived and compared to current design regulations. The recommendations in API (1993) and DNV (1992) are observed to be in poor agreement with the numerically...... obtained p−y curves. The initial stiffness, Epy*, of the p−y curves is found to increase with increasing pile diameter. Considerable uncertainties are observed to be related to small-scale testing, and the evaluations clearly indicate that the accuracy of small-scale testing is increased when increasing...

  18. The Role of Accounting Information in the Survival of Small Scale Businesses in Warri, Delta State, Nigeria

    Directory of Open Access Journals (Sweden)

    Okoh, L. O.

    2012-04-01

    Full Text Available Small scale enterprises play a vital role in the economic development of any country. In Nigeria, the management of these enterprises have been constrained by lack of knowledge of accounting by the stakeholders. This study aimed at examining the roles of accounting information in the survival of small businesses in Warri, Delta State, Nigeria. The study spotlighted the importance of small scale enterprises in the development of Nigerian economy, problems that pose a threat to the survival of small scale businesses and the relevance of accounting information to the operations of a business/organization. Structured questionnaire was employed in the course of gathering relevant data for the study. 100 employees from twenty small scale enterprises in Warri, Delta State were randomly selected for the study. While chi-square statistical technique was used in data analysis. The results indicated among others that the success of small scale business enterprises in Nigeria depends greatly but not solely in accounting information; that most small scale businesses do not keep accounting records due to ignorance about accounting information. The study therefore concluded that for small scale businesses to function successfully, adequate accounting information is necessary therefore managers of small businesses should employ and utilize the services of professional accountants who perform expert and useful accounting services to small scale firms in order to improve on their operational performance.

  19. The potential for small scale hydropower development in the US

    International Nuclear Information System (INIS)

    In an earlier paper (), the potential for small scale hydropower to contribute to US renewable energy supplies, as well as reduce current carbon emissions, was investigated. It was discovered that thousands of viable sites capable of producing significant amounts of hydroelectric power were available throughout the United States. The primary objective of this paper is to determine the cost-effectiveness of developing these small scale hydropower sites. Just because a site has the necessary topographical features to allow small scale hydropower development, does not mean that it should be pursued from a cost-benefit perspective, even if it is a renewable energy resource with minimal effects on the environment. This analysis finds that while the average cost of developing small scale hydropower is relatively high, there still remain hundreds of sites on the low end of the cost scale that are cost-effective to develop right now.

  20. Government Policies on Small Scale Poultry Business and Environmental Health in Indonesia

    Directory of Open Access Journals (Sweden)

    Nyak Ilham

    2015-06-01

    Full Text Available The government paid great attention to develop small-scale poultry business, to reduce poverty alleviation and increase employment opportunities. The government has established various policies to encourage the growth of poultry production cluster (PPC in rural areas. However, the fact shows that these policies have not been able to solve the problems. Small-scale poultry business is particularly vulnerable to economic changes, including animal diseases. The economic crisis of 1997-1998 and avian influenza outbreaks in 2004-2006 had caused most of small-scale enterprises collapsed. Government policies to develop small scale poultry business which is environmental friendly are required so its existence does not disturb the public. Since 2006, the government has established various policies, ie. Village Poultry Farming (VPF and compartment structuring. Based on evaluation and existing cases, the results have no meet the expectation yet, due to lack of sustain supervision. On the other hand, small scale poultry business has been set up on PPC’s under partnerships with companies. The government is expected to continue VPF program and should pay attention to the development of PPC that basically has been accepted by rural communities.

  1. Small-Scale Testing of Laterally Loaded Monopiles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Roesen, Hanne Ravn; Ibsen, Lars Bo;

    2011-01-01

    small-scale laboratory tests. Six quasi-static tests are conducted on piles with diameters of 40mm and 100mm and a slenderness ratio, L/D, of 5. To minimise scale effects, the tests are carried out in a pressure tank at various stress levels. From the obtained load-deflection relationships it is...... shows that small-scale tests applied with overburden pressure are preferable....

  2. Understanding the importance of small-scale fisheries

    OpenAIRE

    Acott, Tim

    2014-01-01

    The livelihoods of small-scale fishermen are under threat in many places across the world. This threat is set against a backdrop of a reported global fisheries ‘crisis’ with 73% of marine stocks reported as either fully exploited, overexploited, depleted or recovering. The focus of fisheries management has often been on the biological and economic dimensions and arguably not enough attention has been given to socio-cultural issues. Capturing the importance of small-scale fisheries from a soci...

  3. Small-Scale CHP Potential in Latvia and Estonia

    OpenAIRE

    Volkova, A.; Latosev, E; Siirde, A

    2009-01-01

    In the research the small-scale CHP potential of Latvia and Estonia has been defined. Factors, which influence the CHP development, were analyzed in this paper, including political, geographic, climatological, legislative and technological factors. For the small-scale CHP potential assessment the three alternatives were chosen. The first alternative is the case, when only the hot water is taken into account. In this case the CHP can work with full load during the whole year because the heat l...

  4. Profitability of Small-Scale Fisheries in Elmina, Ghana

    OpenAIRE

    Isaac Okyere; Cephas Asare; Emmanuel Y. Tenkorang; Asare, Noble K.; Belinda Quaynor; Denis W. Aheto

    2012-01-01

    In order to achieve sustainable fishing livelihoods in coastal communities, data on profitability of small-scale fisheries relative to fish species caught and gear types used by fishermen is required as part of a broader fisheries management strategy. This study was undertaken with this in mind. Interviews were conducted among 60 fishermen between February and March 2010. Economic assessment of small-scale fishing activities were done using questionnaires based on direct market pricing and co...

  5. Solar magnetoconvection and small-scale dynamo: Recent developments in observation and simulation

    CERN Document Server

    Borrero, J M; Schüssler, M; Solanki, S K

    2015-01-01

    A number of observational and theoretical aspects of solar magnetoconvection are considered in this review. We discuss recent developments in our understanding of the small-scale structure of the magnetic field on the solar surface and its interaction with convective flows, which is at the centre of current research. Topics range from plage areas in active regions over the magnetic network shaped by supergranulation to the ubiquituous `turbulent' internetwork fields. On the theoretical side, we focus upon magnetic field generation by small-scale dynamo action.

  6. The Alpha Centauri binary system. Atmospheric parameters and element abundances

    Science.gov (United States)

    Porto de Mello, G. F.; Lyra, W.; Keller, G. R.

    2008-09-01

    Context: The α Centauri binary system, owing to its duplicity, proximity and brightness, and its components' likeness to the Sun, is a fundamental calibrating object for the theory of stellar structure and evolution and the determination of stellar atmospheric parameters. This role, however, is hindered by a considerable disagreement in the published analyses of its atmospheric parameters and abundances. Aims: We report a new spectroscopic analysis of both components of the α Centauri system, compare published analyses of the system, and attempt to quantify the discrepancies still extant in the determinations of the atmospheric parameters and abundances of these stars. Methods: The analysis is differential with respect to the Sun, based on spectra with R = 35 000 and signal-to-noise ratio ≥1000, and employed spectroscopic and photometric methods to obtain as many independent T_eff determinations as possible. We also check the atmospheric parameters for consistency against the results of the dynamical analysis and the positions of the components in a theoretical HR diagram. Results: The spectroscopic atmospheric parameters of the system are found to be T_eff = (5847 ± 27) K, [Fe/H] = +0.24 ± 0.03, log g = 4.34 ± 0.12, and ξt = 1.46 ± 0.03 km s-1, for α Cen A, and T_eff = (5316 ± 28) K, [Fe/H] = +0.25 ± 0.04, log g = 4.44 ± 0.15, and ξt = 1.28 ± 0.15 km s^-1 for α Cen B. The parameters were derived from the simultaneous excitation & ionization equilibria of Fe I and Fe II lines. T_effs were also obtained by fitting theoretical profiles to the Hα line and from photometric calibrations. Conclusions: We reached good agreement between the three criteria for α Cen A. For α Cen B the spectroscopic T_eff is ~140 K higher than the other two determinations. We discuss possible origins of this inconsistency, concluding that the presence of non-local thermodynamic equilibrium effects is a probable candidate, but we note that there is as yet no consensus on

  7. Assessing and managing the resources available to the Senegalese small-scale fisheries

    OpenAIRE

    Diouf, T.

    1993-01-01

    A brief account of the evolution and structure of the marine fisheries of Senegal, West Africa, is presented, with emphasis on the small-scale subsector and on the major recommendations of an international symposium/workshop on this topic, held on February 1993 in Dakar.

  8. Small-scale topology of solar atmosphere dynamics I: wave sources and wave diffraction

    NARCIS (Netherlands)

    Hoekzema, N.M.; Rutten, R.J.; Brandt, P.N.; Shine, R.A.

    2001-01-01

    We study the small-scale topology of dynamical phenomena in the quiet-sun internet w ork atmosphere,using short-duration Fourier analysis of high-resolution filtergram sequences to obtain statistical estimates for the co-location probability of different fine-structure elements and wave modes. In th

  9. Small-scale topology of solar atmosphere dynamics : II : granulation, K2v grains and waves

    NARCIS (Netherlands)

    Hoekzema, N.M.; Rutten, R.J.

    2001-01-01

    We continue studying the small-scale topology of dynamical phenomena in the quiet-sun internetwork atmosphere throug statistical estimation of the co-location probability of different fine-structure elements and wave modes.In this paper we chart spatial alignments between the granular brig tness st

  10. Development of small-scale peat production; Pienturvetuotannon kehittaeminen

    Energy Technology Data Exchange (ETDEWEB)

    Erkkilae, A.; Kallio, E. [VTT Energy, Jyvaeskylae (Finland)

    1997-12-01

    The aim of the project is to develop production conditions, methods and technology of small-scale peat production to such a level that the productivity is improved and competitivity maintained. The aim in 1996 was to survey the present status of small-scale peat production, and research and development needs and to prepare a development plan for small-scale peat production for a continued project in 1997 and for the longer term. A questionnaire was sent to producers by mail, and its results were completed by phone interviews. Response was obtained from 164 producers, i.e. from about 75 - 85 % of small-scale peat producers. The quantity of energy peat produced by these amounted to 3.3 TWh and that of other peat to 265 000 m{sup 3}. The total production of energy peat (large- scale producers Vapo Oy and Turveruukki Oy included) amounted to 25.0 TWh in 1996 in Finland, of which 91 % (22.8 TWh) was milled peat and 9 % (2.2 TWh) of sod peat. The total production of peat other than energy peat amounted to 1.4 million m{sup 3}. The proportion of small-scale peat production was 13 % of energy peat, 11 % of milled peat and 38 % of sod peat. The proportion of small-scale producers was 18 % of other peat production. The results deviate clearly from those obtained in a study of small-scale production in the 1980s. The amount of small-scale production is clearly larger than generally assessed. Small-scale production focuses more on milled peat than on sod peat. The work will be continued in 1997. Based on development needs appeared in the questionnaire, the aim is to reduce environmental impacts and runoff effluents from small- scale production, to increase the efficiency of peat deliveries and to reduce peat production costs by improving the service value of machines by increasing co-operative use. (orig.)

  11. Observations of How Magnetofluid Turbulence Dissipates at Small Scales

    Science.gov (United States)

    Goldstein, M. L.; Sahraoui, Fouad

    2012-01-01

    The solar wind is a turbulent magneto fluid that can be studied intensively at multiple scales. Investigations using single spacecraft have revealed much about the properties of the solar wind throughout the heliosphere (from 0.3 AU to 100 AU). More recently, data from multiple spacecraft have provided further details of both the statistical properties of the turbulence and its small-scale structure. In particular, high time resolution magnetic field measurements from the four Cluster spacecrafl have led to the conclusion that at spatial scales of order the proton inertial length and smaller, the turbulence becomes strongly anisotropic and the power in fluctuations that are perpendicular to the (local) magnetic field is measured to be much larger than that in fluctuations that are parallel to the magnetic field. As the spatial scales approach the electron inertial length, the power is almost completely dissipated. Various analysis techniques and theoretical ideas have been put forward to account for the properties of those measurements. The talk will describe the current state of observations, theory and simulations.

  12. Small-Scale Convection Raising East Anatolia and Northern Iran

    Science.gov (United States)

    Gogus, O.; Pysklywec, R. N.; Sengul Uluocak, E.

    2014-12-01

    The East Anatolia and Iranian plateaus (originally referred as a Turkish-Iranian plateau) are characterized by 1.5-2 km average elevation and have been deformed through Alpine-Himalayan continental collision between the Arabian and Eurasian plates. Recent seismological and geological studies suggest that the lithospheric structure between these two plateaus differs significantly since the Zagros fold-thrust belt in western Iran is associated with a thick lithospheric root (up to 225 km) whereas the East Anatolia seems to be lacking its mantle lithosphere. In this work, we use 2-D numerical experiments to test the applicability of small-scale convection model to account for the anomalous topography and uplift across the Turkish-Iranian plateau. Our models are designed to track the evolution of the surface topography as a response to a mantle flow activity in the step like morphology of the lithospheric base as wells as the temperature field. We test the role of several rheological parameters (e.g., viscosity) and variation in the lithospheric thickness in a series of experiments. Modeling results are tested against various observables for eastern Anatolia and Iran such as surface topography, crustal thickness, and surface strain rate. Our results provide new insight in the geodynamic evolution of Alpine type orogenic systems and suggest alternative mechanism to lithospheric delamination and/or slab break-off for the uplift of mountain belts.

  13. Laser altimetry of small-scale features on 433 Eros from NEAR-Shoemaker.

    Science.gov (United States)

    Cheng, A F; Barnouin-Jha, O; Zuber, M T; Veverka, J; Smith, D E; Neumann, G A; Robinson, M; Thomas, P; Garvin, J B; Murchie, S; Chapman, C; Prockter, L

    2001-04-20

    During the Near Earth Asteroid Rendezvous (NEAR)-Shoemaker's low-altitude flyover of asteroid 433 Eros, observations by the NEAR Laser Rangefinder (NLR) have helped to characterize small-scale surface features. On scales from meters to hundreds of meters, the surface has a fractal structure with roughness dominated by blocks, structural features, and walls of small craters. This fractal structure suggests that a single process, possibly impacts, dominates surface morphology on these scales. PMID:11313491

  14. Engineering development for a small-scale recirculator experiment

    International Nuclear Information System (INIS)

    Lawrence Livermore National Laboratory (LLNL) is evaluating the physics and technology of recirculating induction accelerators for heavy-ion inertial-fusion drivers. As part of this evaluation, the authors are building a small-scale recirculator to demonstrate the concept and to use as a test bed for the development of recirculator technologies. System designs have been completed and components are presently being designed and developed for the small-scale recirculator. This paper discusses results of the design and development activities that are presently being conducted to implement the small-scale recirculator experiments. An, overview of the system design is presented along with a discussion of the implications of this design on the mechanical and electrical hardware. The paper focuses primarily on discussions of the development and design of the half-lattice period hardware and the advanced solid-state modulator

  15. CO2-impacts of a small-scale consumers levy

    International Nuclear Information System (INIS)

    Because of a number of developments (altered budgets of Dutch ministries and implementation of environmental policy plans of energy distribution companies in the Netherlands) the 1993 analyses of the effects of a small-scale consumer levy on the emission of CO2 are updated. First, attention is paid to the conservation impetus as a result of an increase of the energy price for small-scale consumers. Next, the effects that can occur as a consequence of the presently suggested form of the levy (in particular, the exemption of renewable energy and waste heat) are discussed. Subsequently, the alterations of other policy tools, that are necessary in case a higher effectiveness of conservation measures is realized, are dealt with. The direct effect of a higher energy price on the saving behavior of the small-scale consumers is calculated by means of the CENECA-model. 4 tabs., 1 appendix, 8 refs

  16. Small scale wood combustion in Germany. Recent research and trends

    Energy Technology Data Exchange (ETDEWEB)

    Maier, H.; Unterberger, S.; Hein, K.R.G. [Institute of Process Engineering and Power Plant Technology, University of Stuttgart (Germany)

    1998-12-31

    To reduce Europe`s greenhouse gas emission CO{sub 2} it is a challenging task utilising biomass fuels as there are wood or wood residues from the forest industry. The utilisation can be done either in commercially operated medium (> 50 kWth) or full scale (> 1 MWth) decentralised heat and power stations or in small scale (< 50 kWth) domestic heating systems. In small scale heating systems untreated wood logs, wood briquette or wood pellets and in few cases wood chips are used. The present market in Germany is focused on the use of wood logs. Presently, the use of wood pellets in small scale automatically operated boilers < 15 kW especially for low energy houses is discussed more and more. Since 1980 the installation of new wood fired small scale domestic heating systems reached a significant size due to the interest of the customers to have a alternative inhouse heating system and to increase the living comfort. In 1994 the amount of sold small scale heaters in Germany were in total about 133.258 units. The thermal power of in 1994 sold units is estimated of about 1350 MW which is a significant size in total with regard to domestic heating purposes. Since few years there is a clear market trend in Germany towards the installation of open fire stoves. Due to this trend in Germany and the design characteristic of open fire stoves using huge glass doors of glass windows it is very difficult to achieve a further reduction of emissions like CO and unburned volatile hydrocarbons (VOC). In the text the requirements for modern small scale wood fired stoves in Germany as well as the actual stage and trend of research and development (R and D) are discussed 4 refs.

  17. A unified large/small-scale dynamo in helical turbulence

    Science.gov (United States)

    Bhat, Pallavi; Subramanian, Kandaswamy; Brandenburg, Axel

    2016-09-01

    We use high resolution direct numerical simulations (DNS) to show that helical turbulence can generate significant large-scale fields even in the presence of strong small-scale dynamo action. During the kinematic stage, the unified large/small-scale dynamo grows fields with a shape-invariant eigenfunction, with most power peaked at small scales or large k, as in Subramanian & Brandenburg. Nevertheless, the large-scale field can be clearly detected as an excess power at small k in the negatively polarized component of the energy spectrum for a forcing with positively polarized waves. Its strength overline{B}, relative to the total rms field Brms, decreases with increasing magnetic Reynolds number, ReM. However, as the Lorentz force becomes important, the field generated by the unified dynamo orders itself by saturating on successively larger scales. The magnetic integral scale for the positively polarized waves, characterizing the small-scale field, increases significantly from the kinematic stage to saturation. This implies that the small-scale field becomes as coherent as possible for a given forcing scale, which averts the ReM-dependent quenching of overline{B}/B_rms. These results are obtained for 10243 DNS with magnetic Prandtl numbers of PrM = 0.1 and 10. For PrM = 0.1, overline{B}/B_rms grows from about 0.04 to about 0.4 at saturation, aided in the final stages by helicity dissipation. For PrM = 10, overline{B}/B_rms grows from much less than 0.01 to values of the order the 0.2. Our results confirm that there is a unified large/small-scale dynamo in helical turbulence.

  18. New x-ray backlighting results on small-scale structure formation, including liquid-vapor foam-like appearance, in exploding wire Z-pinches and X-pinches

    International Nuclear Information System (INIS)

    Exploding wire and wire array experiments have been carried out in Z-pinch and X-pinch geometry using low current (4.5kA amplitude, 1.4 micros period damped sinusoid) and high current (up to 225 kA, 100 ns) drivers, X-ray backlighter images have been obtained using Mg, Al, Ti, Fe, Ni, NiCr, Cu, brass, Mo, Pd, Ag, Ta, W, Pt, Au, and Ni-coated Ti wires with initial diameters ranging from 7.5 microm (W) to 46 microm (Mg). There were typically two Mo X-pinch x-ray backlighters which generated pulses of <0.5 ns duration from sources small enough to allow resolution of ∼1 microm scale structure in the resulting images. In the high current experiments, images of dense cores within coronal plasmas are obtained with higher Z materials including Ni, Cu, Mo, Pd, Ta, W, Pt and Au; with lower Z materials, only the dense cores are visible in the backlighter images. In all cases a fine structure in the interior of the dense cores, and/or surface instabilities are observed. some of the dense cores show a shock-wave-like structure and others show gaps that open up more rapidly than the wire cores are expanding. The wire interiors develop a foam-like liquid-vapor mix, with some of the bubbles breaching the surface and spewing vapor out of the dense core. The low current experiments follow the same general behavior but require several μs to complete the process instead of 50--100ns. With W and Al wire explosions, step wedges have been used to permit calibrated density measurements to be made of the core (W and Al) and coronal (W) plasmas. The two X-pinches have also been used to radiograph each other, yielding high resolution images of the on-axis collapsing z-pinch and minidiode formation at the X-pinch cross point very close to the time of x-ray burst emission

  19. Sustainable Small-Scale Agriculture in Semi-Arid Environments

    OpenAIRE

    Scott Ingram; Margaret Nelson; Katherine A. Spielmann; Peeples, Matthew A.

    2011-01-01

    For at least the past 8000 years, small-scale farmers in semi-arid environments have had to mitigate shortfalls in crop production due to variation in precipitation and stream flow. To reduce their vulnerability to a shortfall in their food supply, small-scale farmers developed short-term strategies, including storage and community-scale sharing, to mitigate inter-annual variation in crop production, and long-term strategies, such as migration, to mitigate the effects of sustained droughts. W...

  20. Discovery of Small-Scale Spiral Structures in the Disk of SAO 206462 (HD 135344B)(exp 1): Implications for the Physical State of the Disk from Spiral Density Wave Theory

    Science.gov (United States)

    Muto, T.; Grady, C. A.; Hashimoto, J.; Fukagawa, M.; Hornbeck, J. B.; Sitko, M.; Russell, R.; Werren, C.; Cure, M; Currie, T.; Ohashi, N.; Okamoto, Y.; Momose, M.; Honda, M.; Inutsuka, S.; Takeuchi, T.; Dong, R.; Abe, L.; Brandner, W.; Brandt, T.; Carson, J.; Egner, S.; Feldt, M.; Fukue, T.; Goto, M.

    2012-01-01

    We present high-resolution, H-band, imaging observations, collected with Subaru /HiCIAO, of the scattered light from the transitional disk around SAO 206462 (HD 1353448). Although previous sub-mm imagery suggested the existence of the dust-depleted cavity at r theory, and derive a disk aspect ratio of h approx. 0.1, which is consistent with previous sub-mm observations. This model can potentially give estimates of the temperature and rotation profiles of the disk based on dynamical processes. independently from sub-nun observations. It also predicts the evolution of the spiral structures, which can be observable on timescales of 10-20 years, providing conclusive tests of the model. While we cannot uniquely identify the origin of these spirals, planets embedded in the disk may be capable of exciting the observed morphology. Assuming that this is the case, we can make predictions on the locations and, possibly, the masses of the unseen planets. Such planets may be detected by future multi-wavelengths observations,

  1. Application Closed-End Oscillating Heat Pipe for Essential Oil Condensation of the Small Scale Essential Oil Refiner

    OpenAIRE

    Sakultala WANNAPAKHE

    2013-01-01

    This research aimed to investigate the design and building of a small scale essential oil refiner by using heat pipes for essential oil condensation. The device structure of the small scale essential oil refiner was divided into 3 sections as follows: 1) the boiler with a heater for heating, 2) the vapor tube, and 3) the condenser unit. Three patterns of condenser unit were investigated: 1) condensation by water circulation, 2) condensation using heat pipes, and 3) condensation using heat pip...

  2. Nanoflares, Spicules, and Other Small-Scale Dynamic Phenomena on the Sun

    Science.gov (United States)

    Klimchuk, James

    2010-01-01

    There is abundant evidence of highly dynamic phenomena occurring on very small scales in the solar atmosphere. For example, the observed pr operties of many coronal loops can only be explained if the loops are bundles of unresolved strands that are heated impulsively by nanoflares. Type II spicules recently discovered by Hinode are an example of small-scale impulsive events occurring in the chromosphere. The exist ence of these and other small-scale phenomena is not surprising given the highly structured nature of the magnetic field that is revealed by photospheric observations. Dynamic phenomena also occur on much lar ger scales, including coronal jets, flares, and CMEs. It is tempting to suggest that these different phenomena are all closely related and represent a continuous distribution of sizes and energies. However, this is a dangerous over simplification in my opinion. While it is tru e that the phenomena all involve "magnetic reconnection" (the changin g of field line connectivity) in some form, how this occurs depends s trongly on the magnetic geometry. A nanoflare resulting from the interaction of tangled magnetic strands within a confined coronal loop is much different from a major flare occurring at the current sheet form ed when a CME rips open an active region. I will review the evidence for ubiquitous small-scale dynamic phenomena on the Sun and discuss wh y different phenomena are not all fundamentally the same.

  3. Environmentally Sound Small-Scale Energy Projects. Guidelines for Planning.

    Science.gov (United States)

    Bassan, Elizabeth Ann; Wood, Timothy S., Ed.

    This manual is the fourth volume in a series of publications that provide information for the planning of environmentally sound small-scale projects. Programs that aim to protect the renewable natural resources that supply most of the energy used in developing nations are suggested. Considerations are made for physical environmental factors as…

  4. Small-scale Wind Energy Portable Turbine (SWEPT)

    OpenAIRE

    Kishore, Ravi Anant

    2013-01-01

    Large Scale Wind Turbines (LSWTs) have been extensively examined for decades but very few studies have been conducted on the small scale wind turbines (SSWTs) especially for the applications near ground level where wind speed is of order of few meters per second. This study provides the first systematic effort towards design and development of SSWTs (rotor diameter

  5. Small-scale Testing of Bucket Foundations in Sand

    DEFF Research Database (Denmark)

    Knudsen, Bjørn S.; Østergaard, Martin Underlin; Ibsen, Lars Bo

    skirt will provide valuable information of the quasi-static behaviour. For a number of small-scale tests performed in the laboratory at Aalborg University, a bucket foundation will be loaded with varying velocity to investigate the dissipation and general behaviour of bucket foundations used as offshore...

  6. Solar small-scale dynamo and polarity of sunspot groups

    CERN Document Server

    Sokoloff, D; Abramenko, V

    2015-01-01

    In order to clarify a possible role of small-scale dynamo in formation of solar magnetic field, we suggest an observational test for small-scale dynamo action based on statistics of anti-Hale sunspot groups. As we have shown, according to theoretical expectations the small-scale dynamo action has to provide a population of sunspot groups which do not follow the Hale polarity law, and the density of such groups on the time-latitude diagram is expected to be independent on the phase of the solar cycle. Correspondingly, a percentage of the anti-Hale groups is expected to reach its maximum values during solar minima. For several solar cycles, we considered statistics of anti-Hale groups obtained by several scientific teams, including ours, to find that the percentage of anti-Hale groups becomes indeed maximal during a solar minimum. Our interpretation is that this fact may be explained by the small-scale dynamo action inside the solar convective zone.

  7. Small Scale Marine Fisheries: An Extension Training Manual. TR-30.

    Science.gov (United States)

    Martinson, Steven; And Others

    This manual is designed for use in a preservice training program for prospective volunteers whose Peace Corps service will be spent working with small-scale artisanal fishing communities in developing nations. The program consists of 8 weeks of intensive training to develop competencies in marine fisheries technology and fisheries extension work…

  8. 2010 Thin Film & Small Scale Mechanical Behavior Gordon Research Conference

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Thomas Balk

    2010-07-30

    Over the past decades, it has been well established that the mechanical behavior of materials changes when they are confined geometrically at least in one dimension to small scale. It is the aim of the 2010 Gordon Conference on 'Thin Film and Small Scale Mechanical Behavior' to discuss cutting-edge research on elastic, plastic and time-dependent deformation as well as degradation mechanisms like fracture, fatigue and wear at small scales. As in the past, the conference will benefit from contributions from fundamental studies of physical mechanisms linked to material science and engineering reaching towards application in modern applications ranging from optical and microelectronic devices and nano- or micro-electrical mechanical systems to devices for energy production and storage. The conference will feature entirely new testing methodologies and in situ measurements as well as recent progress in atomistic and micromechanical modeling. Particularly, emerging topics in the area of energy conversion and storage, such as material for batteries will be highlighted. The study of small-scale mechanical phenomena in systems related to energy production, conversion or storage offer an enticing opportunity to materials scientists, who can provide new insight and investigate these phenomena with methods that have not previously been exploited.

  9. A Success Story of Organizing Small Scale Farmers in Kenya

    DEFF Research Database (Denmark)

    Buch-Hansen, Mogens

    2012-01-01

    Managing agricultural landscapes for reducing carbon dioxide emissions is believed to be a Payment for Environmental Services mechanism (PES) of major significance after the 2012 Kyoto Protocol era. The big number of small scale farmers in the developing countries, and not least in SSA, will......-Kyoto carbon trade....

  10. Development of small-scale fisheries in Yemen: An exploration

    NARCIS (Netherlands)

    Wagenaar, A.; Haese, D' M.F.C.

    2007-01-01

    Yemen is one of the poorest countries in the world. The development of its fishery sector is increasingly being mentioned as a source of livelihood creation. The aims of this paper are to: (a) provide an overview of the institutional environment in which small-scale fishermen in Yemen operate; (b) i

  11. Environmentally Sound Small-Scale Forestry Projects. Guidelines for Planning.

    Science.gov (United States)

    Ffolliott, Peter F.; Thames, John L.

    This manual, the third in a series of publications that address community development possibilities in developing nations, provides guidelines for small-scale forestry projects that are integrative and conservation-oriented. Chapters focus on: (1) users and uses (specifying targeted audience and general objectives); (2) planning process (including…

  12. Small-Scale Spatial Variability of Ozone in Boulder, Colorado

    Science.gov (United States)

    Deanes, L. N.; Sadighi, K.; Casey, J. G.; Collier, A. M.; Hannigan, M.

    2015-12-01

    Surface ozone (O3) can pose several health risks to humans, such as an increased number of and intensity of asthma attacks. Considering this, it is important that ozone levels are monitored. While municipal air quality monitors are present in cities like Boulder, Colorado, these monitors often only consider regional analysis, neglecting the variability of compounds, such as ozone or carbon monoxide, over smaller distances. Small-scale (approximately 1 kilometer) spatial variability in ozone is important because humans experience these small scales on a daily basis. Using low-cost, next-generation air quality monitors ("pods") developed at the University of Colorado-Boulder, we assessed small-scale spatial variability of surface ozone in Boulder, Colorado. This was done by placing clusters of 4-5 pods within approximately 1 kilometer of each other at specific sites in the city of Boulder. We collected data at two sites: one on the University of Colorado-Boulder campus (i.e., an urban site) and one outside of the city (i.e., a rural site). Pods were left in their positions for one to two weeks allowing for observation of ozone trends. As expected the typical diurnal trend was observed; however, further analysis revealed differences between these daily trends. Data collected by the pods allows for better understanding of small-scale spatial variability of surface ozone and how this may be driven by nearby sources.

  13. Spatial nonlocality of the small-scale solar dynamo

    International Nuclear Information System (INIS)

    We explore the nature of the small-scale solar dynamo by tracking magnetic features. We investigate two previously explored categories of the small-scale solar dynamo: shallow and deep. Recent modeling work on the shallow dynamo has produced a number of scenarios for how a strong network concentration can influence the formation and polarity of nearby small-scale magnetic features. These scenarios have measurable signatures, for which we test using magnetograms from the Narrowband Filter Imager (NFI) on board Hinode. We find no statistical tendency for newly formed magnetic features to cluster around or away from network concentrations, nor do we find any statistical relationship between their polarities. We conclude that there is no shallow or 'surface' dynamo on the spatial scales observable by Hinode/NFI. In light of these results, we offer a scenario in which the subsurface field in a deep solar dynamo is stretched and distorted via turbulence, allowing the small-scale field to emerge at random locations on the photosphere.

  14. Solar small-scale dynamo and polarity of sunspot groups

    Science.gov (United States)

    Sokoloff, D.; Khlystova, A.; Abramenko, V.

    2015-08-01

    In order to clarify a possible role of small-scale dynamo in formation of solar magnetic field, we suggest an observational test for small-scale dynamo action based on statistics of anti-Hale sunspot groups. As we have shown, according to theoretical expectations the small-scale dynamo action has to provide a population of sunspot groups which do not follow the Hale polarity law, and the density of such groups on the time-latitude diagram is expected to be independent on the phase of the solar cycle. Correspondingly, a percentage of the anti-Hale groups is expected to reach its maximum values during solar minima. For several solar cycles, we considered statistics of anti-Hale groups obtained by several scientific teams, including ours, to find that the percentage of anti-Hale groups becomes indeed maximal during a solar minimum. Our interpretation is that this fact may be explained by the small-scale dynamo action inside the solar convective zone.

  15. Small-Scale Structuring Of Ellerman Bombs at Solar Limb

    CERN Document Server

    Nelson, C J; Doyle, J G; Freij, N; Erdélyi, R

    2014-01-01

    Ellerman bombs (EBs) have been widely studied in recent years due to their dynamic, explosive nature and apparent links to the underlying photospheric magnetic field implying that they may be formed by magnetic reconnection in the photosphere. Despite a plethora of researches discussing the morphologies of EBs, there has been a limited investigation of how these events appear at the limb, specifically, whether they manifest as vertical extensions away from the disc. In this article, we make use of high-resolution, high-cadence observations of an AR at the solar limb, collected by the CRISP instrument, to identify EBs and infer their physical properties. The upper atmosphere is also probed using the SDO/AIA. We analyse 22 EB events evident within these data, finding that 20 appear to follow a parabolic path away from the solar surface at an average speed of 9 km s^(-1), extending away from their source by 580 km, before retreating back at a similar speed. These results show strong evidence of vertical motions ...

  16. Sampling problems: The small scale structure of precipitation

    Science.gov (United States)

    Crane, R. K.

    1981-01-01

    The quantitative measurement of precipitation characteristics for any area on the surface of the Earth is not an easy task. Precipitation is rather variable in both space and time, and the distribution of surface rainfall data given location typically is substantially skewed. There are a number of precipitation process at work in the atmosphere, and few of them are well understood. The formal theory on sampling and estimating precipitation appears considerably deficient. Little systematic attention is given to nonsampling errors that always arise in utilizing any measurement system. Although the precipitation measurement problem is an old one, it continues to be one that is in need of systematic and careful attention. A brief history of the presently competing measurement technologies should aid us in understanding the problem inherent in this measurement task.

  17. Development of small-scale peat production. Final report

    International Nuclear Information System (INIS)

    The objective of this three year project was to develop the production conditions, methods and technology of small-scale peat producers so that the profitability of small-scale peat production is improved and the competitiveness remains. The aim in 1996 was to determine the present situation of small-scale peat producers, and the research and development needs, as well as to prepare a development plan of the small-scale peat production. The aims for 1997 were: the diminishing of the environmental hazards and the run-off waters of the small-scale peat production, the intensification of the peat deliveries from small-scale peat production, and the reduction of the peat production costs by improving the degree of utilization of the equipment via common or shared use. According to the results of the study peat production in Finland in 1996 was 25.0 TWh in total. The share of milled peat was 91 % of the peat production, and that of sod peat 9.0 %. About 1 440 000 m3 of other than energy peat was produced. The share of energy peat producers, replying to the questionnaire was 13 % (3.3 TWh) and the share of other peat producers was 18 %. Peat was produced from the area of 59 000 ha, the share of small-scale peat producers was 9 250 ha corresponding to about 16 % of the total peat production area. The share of milled peat of the peat produced by small-scale peat producers was about 73 %. The number of peat produces replying to the questionnaire was 164. The level of water protection and other environmental protection of twelve peat producers in the Southern Ostrobothnia were studied. According to the survey the main shortages comprised too small or lacking settling ponds. Also other shortages in environmental protection were observed. Feedback on the survey, as well as guidance and suggestions for improvements were given to the producers. Deliveries of peat by the small-scale peat producers to the Rauhalahti power plant of Jyvaeskylaen Energiantuotanto Oy were reviewed in

  18. Effect of orientation and loading rate on compression behavior of small-scale Mo pillars

    International Nuclear Information System (INIS)

    Recently, much work has focused on the size effect in face centered cubic (fcc) structures, however few pillar studies have focused on body centered cubic (bcc) metals. This paper explores the role of bcc crystal structure on the size effect, through compression testing of [001] and [235] Molybdenum (Mo) small-scale pillars manufactured by focused ion beam (FIB). The pillar diameters ranged from 200 nm to 5 μm. Results show that the relationship between yield stress and diameter exhibits an inverse relationship (σy ∝ d-0.22 for [001] Mo and σy ∝ d-0.34 for [235] Mo) weaker than that observed for face centered cubic (fcc) metals (σy ∝ d-0.6to-1.0). Additional tests at various loading rates revealed that small-scale Mo pillars exhibit a strain rate sensitivity similar to bulk Mo.

  19. Capturing Compostables: A Case Study of Small Scale Composting in Vancouver

    OpenAIRE

    Blakeway, Elizabeth Ashley

    2013-01-01

    This research study explores the role of small-scale composting for the processing of food scraps in the City of Vancouver within the nexus of organics diversion and the municipality’s Greenest City policy goals. Conceptually the study is informed by the integration of public policy, the policy cycle, and concepts relating to diversified, scalable technology. Empirically the study adopts a soft systems methodology that employs an inquiry-based approach, predicated on in-depth semi-structure...

  20. Export horticulture – empowering female small-scale farmers in Kenya?

    OpenAIRE

    Velte, Maria; Dannenberg, Peter

    2014-01-01

    Export horticulture is one of Kenya’s most dynamic sectors, with the Mount Kenya Region playing a crucial role as a result of its professional large- and small-scale production and marketing structures. The sector is consequently referred to as a “success story of African regional development” (Dolan and Sutherland 2002: 1). A qualitative case study was carried out to understand the impacts on gender inequality of the integration of horticultural smallholdings into the fresh fruit and vegetab...

  1. Impact of radiative decay on cosmic string dynamics at small scales

    OpenAIRE

    Stuckey, Stephanie

    2012-01-01

    Cosmic strings are topological defects appearing as extended solutions in many high energy physics scenarios. Observation of signatures expected due to the presence of cosmic string networks could provide critical evidence in distinguishing and constraining fundamental cosmological and particle physics theories. Large scale evolution of cosmic string is well understood but the dynamics influenced by small scale structure remains unclear. Radiation back-reaction is expected t...

  2. Biofuels in Africa: growing small-scale opportunities

    Energy Technology Data Exchange (ETDEWEB)

    Sulle, Emmanuel [Tanzania Natural Resources Forum (Tanzania, United Republic of); Fauveaud, Swan [Renewable Energy Group, Environment and Solidarity (France); Vermeulen, Sonja

    2009-11-15

    Global demand for climate-friendly transport fuels is driving vast commercial biofuels projects in developing countries. At the opposite end of the spectrum is small-scale bioenergy production. This offers a way for the poor to meet their energy needs and diversify their livelihoods without compromising food security or environmental integrity. Governments hope that it will be possible to combine the advantages of both large- and small-scale production of biofuels to generate energy security and GDP at the national level, while opening up local opportunities. In Africa, most governments are keen to attract foreign direct investment, and see big business as a strategic means of scaling up rural development. But there is a middle way. By encouraging business models that bridge large and small enterprise, African governments could show that commercial competition can go hand in hand with a range of real local benefits.

  3. Leadership solves collective action problems in small-scale societies.

    Science.gov (United States)

    Glowacki, Luke; von Rueden, Chris

    2015-12-01

    Observation of leadership in small-scale societies offers unique insights into the evolution of human collective action and the origins of sociopolitical complexity. Using behavioural data from the Tsimane forager-horticulturalists of Bolivia and Nyangatom nomadic pastoralists of Ethiopia, we evaluate the traits of leaders and the contexts in which leadership becomes more institutional. We find that leaders tend to have more capital, in the form of age-related knowledge, body size or social connections. These attributes can reduce the costs leaders incur and increase the efficacy of leadership. Leadership becomes more institutional in domains of collective action, such as resolution of intragroup conflict, where collective action failure threatens group integrity. Together these data support the hypothesis that leadership is an important means by which collective action problems are overcome in small-scale societies. PMID:26503683

  4. Solar Receiver Design and Verification for Small Scale Polygeneration Unit

    OpenAIRE

    Aichmayer, Lukas

    2011-01-01

    Against a backdrop of our world’s changing climate solar thermal power generation shows great potential to move global energy production away from fossil fuels to non-polluting sources. The Department of Energy Technology at the Royal Institute of Technology Stockholm is contributing to the development and research of solar thermal power by building a solar driven small scale polygeneration unit based on an externally fired micro gas turbine. This project focused on the design, analysis and v...

  5. The small-scale turbulent dynamo in smoothed particle magnetohydrodynamics

    OpenAIRE

    Tricco, Terrence S.; Price, Daniel J.; Federrath, Christoph

    2016-01-01

    Supersonic turbulence is believed to be at the heart of star formation. We have performed smoothed particle magnetohydrodynamics (SPMHD) simulations of the small-scale dynamo amplification of magnetic fields in supersonic turbulence. The calculations use isothermal gas driven at rms velocity of Mach 10 so that conditions are representative of star-forming molecular clouds in the Milky Way. The growth of magnetic energy is followed for 10 orders in magnitude until it reaches saturation, a few ...

  6. A community small-scale wind generation project in Peru

    OpenAIRE

    Ferrer Martí, Laia; Garwood, Anna; Chiroque, José; Escobar, Rafael; Coello, Javier; Castro, Miguel

    2010-01-01

    Electrification systems based on renewable energy have proven to be suitable for providing decentralized electricity to isolated communities. Electricity generated through wind power is one of the technical options available, although infrequently used to date. This article aims to describe the main aspects of technical design, implementation and management of the first small-scale community wind generation project for rural electrification in Peru. This project took place in t...

  7. Investigation of the Feasibility of a Small Scale Transmutation Device

    OpenAIRE

    Sit, Roger Carson

    2009-01-01

    This dissertation presents the design and feasibility of a small-scale, fusion-based transmutation device incorporating a commercially available neutron generator. It also presents the design features necessary to optimize the device and render it practical for the transmutation of selected long-lived fission products and actinides.Four conceptual designs of a transmutation device were used to study the transformation of seven radionuclides: long-lived fission products (Tc-99 and I-129), sho...

  8. Effectiveness of 3D Printing in Small Scale Production

    OpenAIRE

    Huttunen, Jani

    2015-01-01

    The purpose of this thesis is to estimate the effectiveness of two 3D printing methods (fused deposition modeling and stereolithography) for prototyping and small-scale production at a 3D printing laboratory at Metropolia University of Applied Sciences. The 3D printing technology is currently developing, so not much literature is available yet. That is the reason why before actual production a thorough analysis is needed of the advantages and disadvantages and of the effectiveness of the...

  9. Development of a small scale orange juice extractor

    OpenAIRE

    Olaniyan, A. M.

    2010-01-01

    A small scale motorized orange juice extractor was designed and fabricated, using locally-available construction materials. The essential components of the machine include feeding hopper, top cover, worm shaft, juice sieve, juice collector, waste outlet, transmission belt, main frame, pulleys and bearings. In operation, the worm shaft conveys, crushes, presses and squeezes the fruit to extract the juice. The juice extracted is filtered through the juice sieve into juice collector while the re...

  10. Commissioning of a Small-Scale Wastewater Treatment Plant

    OpenAIRE

    Shunova, Kristina

    2016-01-01

    The thesis is dedicated to the wastewater treatment process study, while providing commissioning of a small-scale wastewater treatment plant on the territory of a national park in Sochi, Russia. The objective of the study was to conduct a commissioning as well as research ways to increase the oxidation capacity of the wastewater treatment facility. The effluent quality from the treatment facility was to correspond with standards issued by Russian authorities. Research was based on ...

  11. METIERS IN SMALL SCALE FISHERIES IN N.E. AEGEAN

    OpenAIRE

    KAVADAS Stefanos; Petrakis, George; SIAPATIS Apostolis; BARBAS Thomas; DAMALAS DIMITRIOS; ADAMIDOU A.; MAINA I.; KORNARAKI L.

    2012-01-01

    For the numerous métiers of the small scale fisheries in the North-Eastern Aegean sea (Lesvos and Limnos isl.), herein we present the catch composition per métier, the fishing effort and the estimation of total production. Daily logbooks were distributed to 20 professional coastal fishermen to record for a one year period their fishing activity. In total, 68 type of fisheries were reported, grouped in 20 different métiers...

  12. A cybernetic future for small-scale fisheries

    OpenAIRE

    2014-01-01

    This article discusses the future of indigenous Sami fisheries in cybernetic fisheries systems characterized by increasing effectivization and industrialisation. It empirically investigates the past and present development of a small-scale fjord fishery in Porsanger, northern Norway, which has been a major part of the material basis for indigenous Sami culture and settlements in the area. The article utilises historical vessel registries and fishers’ vessel career narratives fr...

  13. Effect of generator usage on small scale businesses in Nigeria

    OpenAIRE

    Ikhuosho-Asikhia, Juliet

    2014-01-01

    Energy has a major impact on socio-economic development by playing a key role in economic, social and political advancement of any Nation. Inadequate supply of energy limits advancement in all spheres thereby causing depreciation in the quality of life among citizens. Small scale businesses in Nigeria also have their fair share of the effects of inadequate energy supply in Nigeria. The aim of this study is to analyze the awareness, economic and environmental effects and attitudes of gener...

  14. DEFINING SMALL-SCALE FARMERS IN THE SOUTH AFRICAN CONTEXT

    OpenAIRE

    Kirsten, Johann F.; Zyl, Johan van

    1998-01-01

    South African agriculture is comprised of mainly two categories of farmers -- the subsistence farmers in the former homeland areas and the large-scale commercial (mainly white) farmers. This is in contrast with the situation in many other countries in the world where one would find a whole range of farm sizes, ranging from the very small or subsistence farmer to the very large farmer/agribusiness. The paper highlights the situation of small-scale farmers in an international context and compar...

  15. Optimal Combustion Conditions for a Small-scale Biomass Boiler

    OpenAIRE

    Viktor Plaček; Cyril Oswald; Jan Hrdlička

    2012-01-01

    This paper reports on an attempt to achieve maximum efficiency and lowest possible emissions for a small-scale biomass boiler. This aim can be attained only by changing the control algorithm of the boiler, and in this way not raising the acquisition costs for the boiler. This paper describes the experimental facility, the problems that arose while establishing the facility, and how we have dealt with them. The focus is on discontinuities arising after periodic grate sweeping, and on finding t...

  16. Small-scale heterogeneity in sediments : experimental and modelling investigations.

    OpenAIRE

    Stockdale, Anthony

    2008-01-01

    This thesis consists of several studies relating to small-scale heterogeneity in sediments. The principal aim was to further our understanding of processes occurring at microniches. The individual studies consist of: 1) a critical review of previous studies of microniches that used probes with high spatial resolution and modelling approaches; 2) an experimental study of analysis of oxyanions in sediment at high resolution that applied a newly developed preparation method for a combined AgI/Fe...

  17. Small scale wind energy harvesting with maximum power tracking

    OpenAIRE

    Joaquim Azevedo; Fábio Mendonça

    2015-01-01

    It is well-known that energy harvesting from wind can be used to power remote monitoring systems. There are several studies that use wind energy in small-scale systems, mainly with wind turbine vertical axis. However, there are very few studies with actual implementations of small wind turbines. This paper compares the performance of horizontal and vertical axis wind turbines for energy harvesting on wireless sensor network applications. The problem with the use of wind energy is that most of...

  18. Costs for renewable electricity. Small-scale hydroelectric power

    International Nuclear Information System (INIS)

    The aim of the study on the title subject is to provide an objective basis for the determination of the assumptions that are used for the calculation of the so-called uneconomic top of electricity production from renewable energy sources, carried out by ECN and KEMA. The results will be used for the determination of the subsidy tariffs for small-scale hydroelectric power plants and is part of the Environmental Quality of Electricity Production (MEP, abbreviated in Dutch) policy

  19. Characteristic of Small Scale Food Industry Cluster in West Sumatera

    Directory of Open Access Journals (Sweden)

    Gunarif Taib

    2014-04-01

    Full Text Available Clusters of small-scale food industries have different characteristics with industrial cluster in general. These characteristics need to know to develop a plan for cluster development. This study was conducted to determine charasteristics clusters of small-scale food industry, especially in West Sumatra. For the analysis of the components of industrial and technological components that affect the development of small-scale food industry cluster in West Sumatra. All variables influence the level of industrial components and technology components were analyzed using the program "Statistical Product and Service Solutions (SPSS". The survey results revealed that the industrial component is influenced by the core industry (level of difficulty in capital gain and raw materials, the buyer (customer satisfaction, related industry (quality and continuity of supply of packaging and institutional support (coaching on marketing and capitalization as well as guidance on the production of sanitary and food safety. Component technology is influenced by organoware (production management and marketing management and humanware (innovation and trust among the members.

  20. Spatial Nonlocality of the Small-Scale Solar Dynamo

    CERN Document Server

    Lamb, Derek A; DeForest, Craig E

    2014-01-01

    We explore the nature of the small-scale solar dynamo by tracking magnetic features. We investigate two previously-explored categories of the small-scale solar dynamo: shallow and deep. Recent modeling work on the shallow dynamo has produced a number of scenarios for how a strong network concentration can influence the formation and polarity of nearby small-scale magnetic features. These scenarios have measurable signatures, which we test for here using magnetograms from the Narrowband Filter Imager (NFI) on Hinode. We find no statistical tendency for newly-formed magnetic features to cluster around or away from network concentrations, nor do we find any statistical relationship between their polarities. We conclude that there is no shallow or "surface" dynamo on the spatial scales observable by Hinode/NFI. In light of these results, we offer a scenario in which the sub-surface field in a deep solar dynamo is stretched and distorted via turbulence, allowing the field to emerge at random locations on the photo...

  1. The legalization of small scale mining in Colombia

    Directory of Open Access Journals (Sweden)

    Alexandra Urán

    2013-11-01

    Full Text Available The following article presents conceptual and analytical elements that allow us to broaden the debate about the legalization of the mining in Colombia. Looking for items to be able to propose alternatives in order to consolidate a new mining process socially and environmentally sustainable, claiming the value of the ancestral practices and forms of the redistributive production. To this end, it is necessary to start with the discussion of the concepts of formalization and legality, so that we can generate a theoretical framework that will allow us to explore such delicate matter, we will continue to make the framework socio-political, in which it is based that strategy. Then there is a brief context of thereformulation of legal mining, focusing our attention particularly standards which involves or has effects on artisanal mining and/or small-scale mining. There we will find ourselves with a debate on the typology of the mining and the current difficulties to define schemasof legalization or formalization of small-scale mining in Colombia. To conclude with a proposal to formalize as a mechanism of transition to an administrative system - legislativethat will connect more effectively with the realities and skills of the ethnic communities that practice small-scale mining.

  2. Driving small-scale fisheries in developing countries

    Directory of Open Access Journals (Sweden)

    Steven W. Purcell

    2015-06-01

    Full Text Available Small-scale fisheries (SSFs engage the vast majority of the world’s fishers but are struggling to keep pace with coastal populations, and stocks are declining to levels that threaten reproductive capacity. The provision of food and livelihoods to low-income fishers into the future will be unlikely without radical changes to fisheries policy. We draw on repeating analogies of driving a car to illustrate fundamental reforms needed for driving (managing small-scale fisheries. SSFs will continue to be unsustainable by relying too heavily on output controls (the ‘brake’. Managers need to move away from routinely using moratoria (i.e. the ‘handbrake’ as a management measure, although these measures may be needed as a last resort. Scientists (‘backseat drivers’ must engage more directly with fishery management agencies to understand their constraints and needs. Resource managers must come to terms with regulating fishing inputs (the ‘accelerator’ by imposing limited-entry rules, vessel limitations or short fishing seasons in addition to sensible output controls. Reforms to resource management will need to entail unpopular measures if small-scale fisheries are to deliver sustained benefits to fishing communities into the future.

  3. A unified large/small-scale dynamo in helical turbulence

    CERN Document Server

    Bhat, Pallavi; Brandenburg, Axel

    2015-01-01

    We use high resolution direct numerical simulations to show that helical turbulence can generate large-scale fields even in the presence of strong small-scale fields.During the kinematic stage, the unified large/small-scale dynamo grows fields with a shape-invariant eigenfunction, with most power peaked at small scales or large $k$. Nevertheless, the large-scale field can be clearly detected as an excess power at small $k$ in the negatively polarized component of the energy spectrum for a forcing with positively polarized waves. The strength of such kinematic large-scale field $\\overline{B}$ relative to the total rms field $B_{rms}$ decreases with increasing magnetic Reynolds number, $Re_{M}$. However, as the Lorentz force becomes important, the field orders itself by saturating on successively larger scales. The magnetic power spectrum in the saturated state shows peaks at both the forcing wavenumber $k=k_f$, and at the box scale, $k=1$. The magnetic integral scale for the positively polarized waves, increas...

  4. Sustainable Small-Scale Agriculture in Semi-Arid Environments

    Directory of Open Access Journals (Sweden)

    Scott Ingram

    2011-03-01

    Full Text Available For at least the past 8000 years, small-scale farmers in semi-arid environments have had to mitigate shortfalls in crop production due to variation in precipitation and stream flow. To reduce their vulnerability to a shortfall in their food supply, small-scale farmers developed short-term strategies, including storage and community-scale sharing, to mitigate inter-annual variation in crop production, and long-term strategies, such as migration, to mitigate the effects of sustained droughts. We use the archaeological and paleoclimatic records from A.D. 900-1600 in two regions of the American Southwest to explore the nature of variation in the availability of water for crops, and the strategies that enhanced the resilience of prehistoric agricultural production to climatic variation. Drawing on information concerning contemporary small-scale farming in semi-arid environments, we then suggest that the risk coping and mitigation strategies that have endured for millennia are relevant to enhancing the resilience of contemporary farmers' livelihoods to environmental and economic perturbations.

  5. The small-scale treatability study sample exemption

    International Nuclear Information System (INIS)

    In 1981, the Environmental Protection Agency (EPA) issued an interim final rule that conditionally exempted ''waste samples collected solely for the purpose of monitoring or testing to determine their characteristics or composition'' from RCRA Subtitle C hazardous waste regulations. This exemption [40 CFR 261.4(d)] apples to the transportation of samples between the generator and testing laboratory, temporary storage of samples at the laboratory prior to and following testing, and storage at a laboratory for specific purposes such as an enforcement action. However, the exclusion did not include large-scale samples used in treatability studies or other testing at pilot plants or other experimental facilities. As a result of comments received by the EPA subsequent to the issuance of the interim final rule, the EPA reopened the comment period on the interim final rule on September 18, 1987, and specifically requested comments on whether or not the sample exclusion should be expanded to include waste samples used in small-scale treatability studies. Almost all responders commented favorably on such a proposal. As a result, the EPA issued a final rule (53 FR 27290, July 19, 1988) conditionally exempting waste samples used in small-scale treatability studies from full regulation under Subtitle C of RCRA. The question of whether or not to extend the exclusion to larger scale as proposed by the Hazardous Waste Treatment Council was deferred until a later date. This information Brief summarizes the requirements of the small-scale treatability exemption

  6. Evolution of second-generation stars in stellar disks of globular and nuclear clusters: ω Centauri as a test case

    International Nuclear Information System (INIS)

    Globular clusters (GCs) and many nuclear clusters (NCs) show evidence of hosting multiple generations of stellar populations. Younger stellar populations in NCs appear to reside in disk-like structures, including the NC in our own Galactic center as well as in M31. Kinematic studies of the anomalous GC ω Centauri, thought to possibly be a former dwarf galaxy (or a galactic nucleus), show evidence of hosting a central, kinematically cold disk component. These observations suggest that formation of second- (or multiple) generation stars may occur in flattened disk-like structures. Here, we use detailed N-body simulations to explore the possible evolution of such stellar disks embedded in GCs. We follow the long-term evolution of a disk-like structure similar to that observed in ω Centauri and study its properties. We find that a stellar-disk-like origin for second-generation stellar populations can leave behind significant kinematic signatures in properties of the clusters, including an anisotropic distribution and lower velocity dispersions, which can be used to constrain the origin of second-generations stars and their dynamical evolution.

  7. RAVE stars tidally stripped/ejected from $\\omega$ Centauri globular cluster

    CERN Document Server

    Fernández-Trincado, J G; Vieira, K; Moreno, E; Bienaymé, O; Reylé, C; Valenzuela, O; Pichardo, B; Robles-Valdez, F; Martins, A M M

    2015-01-01

    Using six-dimesional phase-space information from the Fourth Data release of the Radial Velocity Experiment (RAVE) over the range of Galactic longitude 240$^{\\circ}V_{esc,0}$) from the cluster, we identified 15 stars as having close encounters with $\\omega$ Centauri: (\\textit{i}) 8 stars with relative velocities $V_{rel} 200 $ kms$^{-1}$ during close encounters, and seems unlikely that they have been ejected from $\\omega$ Centauri. We also confirm the link between J131340.4-484714 as potential member of $\\omega$ Centauri, and probably ejected $\\sim$ 2.0 Myr ago, with a relative velocity $V_{rel}\\sim80$ kms$^{-1}$.

  8. Multiwavelength Constraints on the Dynamical History of Omega Centauri

    Science.gov (United States)

    Haggard, Daryl; Cool, A. M.; Arias, T.; Brochmann, M. B.; Dorfman, J.; Gafford, A.; White, V.; Anderson, J.; Davies, M. B.

    2012-09-01

    Omega Centauri, the Milky Way's most massive and enigmatic old stellar cluster, offers a treasure trove of astronomical discovery and controversy. Is the cluster a globular or a dwarf galaxy remnant? Does it host a massive central black hole? What are the origins and dynamical histories of the cluster's multiple stellar populations? I will discuss our multiwavelength imaging and spectroscopic campaigns, and in particular a new Chandra X-ray flux limit on the cluster's purported IMBH. These observations also probe Omega Cen's binary populations and shed light on the cluster's dynamical history.

  9. The globular cluster ω Centauri and its RR Lyrae variables

    International Nuclear Information System (INIS)

    The significance of some of the unusual characteristics of the globular cluster ωCentauri in various fundamental problems is explored. Interest is centred on the properties of the cluster RR Lyraes, and what they can contribute to studies of early cluster chemical enrichment, stellar pulsation, the distance scale, stellar evolution, stellar ages and the Oosterhoff period-shift problem. This article, which is intended to highlight problems and progress rather than give a comprehensive review, includes new results based on photometry of the RR Lyraes, red giants, subgiants, horizontal-branch and main sequence stars in the cluster. (author)

  10. Manual for development of small scale hydroelectric projects by public entities

    Energy Technology Data Exchange (ETDEWEB)

    1981-03-01

    This manual is designed to provide guidance to towns, cities, counties and other political subdivisions which are interested in undertaking or participating in small scale hydroelectric (SSH) development within or close to their territorial boundaries. The manual is primarily directed to those political subdivisions which either own or have access to a site, are interested in exploring the prospects for development of the site and do not have longstanding experience in the electric power development. For purposes of this manual a small scale hydroelectric project is a project of 25 to 30 MWs or less and utilizes an existing dam or structure or utilizes the site characteristics of partially breached dams or structures. As the reader will observe from the discussion that follows, several incentives under federal and state law have been implemented which favor small scale hydroelectric development at existing sites. This manual is designed to assist political subdivisions in taking advantage of these incentives and devising strategies for development. The manual will provide information to political subdivisions as to what to expect in the development process and the kinds of informed questions to ask of paid advisers. The manual, however, cannot be and should not be used as a substitute for competent advice and assistance from experienced lawyers, engineers, accountants and financing experts.

  11. [Qualitative evaluation of employer requirements associated with occupational health and safety as good practice in small-scale enterprises].

    Science.gov (United States)

    Kuroki, Naomi; Miyashita, Nana; Hino, Yoshiyuki; Kayashima, Kotaro; Fujino, Yoshihisa; Takada, Mikio; Nagata, Tomohisa; Yamataki, Hajime; Sakuragi, Sonoko; Kan, Hirohiko; Morita, Tetsuya; Ito, Akiyoshi; Mori, Koji

    2009-09-01

    The purpose of this study was to identify what motivates employers to promote good occupational health and safety practices in small-scale enterprises. Previous studies have shown that small-scale enterprises generally pay insufficient attention to issues of occupational health and safety. These findings were mainly derived from questionnaire based surveys. Nevertheless, some small-scale enterprises in which employers exercise good leadership do take a progressive approach to occupational health and safety. Although good practices can be identified in small-scale enterprises, it remains unclear what motivates employers in small-scale enterprises to actively implement occupational health and safety practices. We speculated that identifying employer motivations in promoting occupational health would help to spread good practices among small-scale enterprises. Using a qualitative approach based on the KJ methods, we interviewed ten employers who actively promote occupational health and safety in the workplace. The employers were asked to discuss their views of occupational health and safety in their own words. A semi-structured interview format was used, and transcripts were made of the interviews. Each transcript was independently coded by two or more researchers. These transcripts and codes were integrated and then the research group members discussed the heading titles and structural relationships between them according to the KJ method. Qualitative analysis revealed that all the employers expressed a strong interest in a "good company" and "good management". They emphasized four elements of "good management", namely "securing human resources", "trust of business partners", "social responsibility" and "employer's health condition itself", and considered that addressing occupational health and safety was essential to the achievement of these four elements. Consistent with previous findings, the results showed that implementation of occupational health and safety

  12. Small-Scale Combined Heat and Power Plants Using Biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Salomon-Popa, Marianne [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Energy Technology

    2002-11-01

    In this time period where energy supply and climate change are of special concern, biomass-based fuels have attracted much interest due to their plentiful supply and favorable environmental characteristics (if properly managed). The effective capture and continued sustainability of this renewable resource requires a new generation of biomass power plants with high fuel energy conversion. At the same time, deregulation of the electricity market offers new opportunities for small-scale power plants in a decentralized scheme. These two important factors have opened up possibilities for small-scale combined heat and power (CHP) plants based on biofuels. The objective of this pre-study is to assess the possibilities and technical limitations for increased efficiency and energy utilization of biofuels in small size plants (approximately 10 MWe or lower). Various energy conversion technologies are considered and proven concepts for large-scale fossil fuel plants are an especially important area. An analysis has been made to identify the problems, technical limitations and different possibilities as recognized in the literature. Beyond published results, a qualitative survey was conducted to gain first-hand, current knowledge from experts in the field. At best, the survey results together with the results of personal interviews and a workshop on the role of small-scale plants in distributed generation will serve a guideline for future project directions and ideas. Conventional and novel technologies are included in the survey such as Stirling engines, combustion engines, gas turbines, steam turbines, steam motors, fuel cells and other novel technologies/cycles for biofuels. State-of-the-art heat and power plants will be identified to clarify of the advantages and disadvantages as well as possible obstacles for their implementation.

  13. Small-scale Conformity of the Virgo Cluster Galaxies

    Science.gov (United States)

    Lee, Hye-Ran; Lee, Joon Hyeop; Jeong, Hyunjin; Park, Byeong-Gon

    2016-06-01

    We investigate the small-scale conformity in color between bright galaxies and their faint companions in the Virgo Cluster. Cluster member galaxies are spectroscopically determined using the Extended Virgo Cluster Catalog and the Sloan Digital Sky Survey Data Release 12. We find that the luminosity-weighted mean color of faint galaxies depends on the color of adjacent bright galaxy as well as on the cluster-scale environment (gravitational potential index). From this result for the entire area of the Virgo Cluster, it is not distinguishable whether the small-scale conformity is genuine or if it is artificially produced due to cluster-scale variation of galaxy color. To disentangle this degeneracy, we divide the Virgo Cluster area into three sub-areas so that the cluster-scale environmental dependence is minimized: A1 (central), A2 (intermediate), and A3 (outermost). We find conformity in color between bright galaxies and their faint companions (color–color slope significance S ∼ 2.73σ and correlation coefficient {cc}∼ 0.50) in A2, where the cluster-scale environmental dependence is almost negligible. On the other hand, the conformity is not significant or very marginal (S ∼ 1.75σ and {cc}∼ 0.27) in A1. The conformity is not significant either in A3 (S ∼ 1.59σ and {cc}∼ 0.44), but the sample size is too small in this area. These results are consistent with a scenario in which the small-scale conformity in a cluster is a vestige of infallen groups and these groups lose conformity as they come closer to the cluster center.

  14. Cyclic Behavior of the Sun's Small-scale Magnetic Elements

    Science.gov (United States)

    Wang, Jingxiu; Jin, C.

    2011-05-01

    With the unique database from the Michelson Doppler Imager on board the Solar and Heliospheric Observatory in an interval embodying solar cycle 23, the cyclic behavior of solar small-scale magnetic elements is studied. More than 13 million small-scale magnetic elements are selected, and their cyclic behavior is analyzed in comparison with the changes of sunspot numbers and active region magnetic flux. From the small to large end of the flux spectrum, the variations of numbers and total flux of the network elements show no correlation, anti-correlation, and correlation with sunspots, respectively. The anti-correlated elements, covering the flux of (2.9-32.0)×1018 Mx, occupy 77.2% of the total element number and 37.4% of the quiet-Sun flux. Unlike the correlated elements, which follow the sunspot butterfly diagram, the anti-correlated elements cover very broad range of latitude and do not show clear latitude migration during the cycle. These results provide insight for understanding the anti-correlations of small-scale magnetic activity during the solar cycle. The quiet regions dominate the Sun's magnetic flux for about 8 years in the 12.25 year duration of cycle 23, their monthly average magnetic flux is 1.12 times that of the active regions in the cycle. For the 28 continuous months from July 2007 to October 2009, the six-month running average ratio of quiet region flux to that of the total Sun is larger than 90.0%, which characterizes the gram minima in cycles 23 and 24 very well.

  15. Small-scale power plant potential in Finland

    International Nuclear Information System (INIS)

    The presentation discusses the small-scale power plant potential in Finland. The study of the potential is limited to W-scale power plants producing both electric power and heat using solid fuels. The basic power plant dimensioning and electric power load determination is based on traditional boiler and gas turbine technology. The possible sites for power plants are communities using district heating, and industrialized sites needing process steam or heat. In 1990 70 % (17 TWh) of district heat was produced by gas turbines. Ten communities have an own back-pressure power plant, and 40 communities buy heat from industrial plants, owing back-pressure power generation. Additionally about 40 communes buy district heat from companies, owned by power companies and industry. Estimates of small-scale power plant potential has been made plant wise on the basis of district heat loads and industrial heat needs. The scale of the plants has been limited to scale 3 MWe or more. The choosing of the fuel depends on the local conditions. The cheapest indigenous fuels in many communes are industrial wood wastes, and both milled and sod peat. The potential of steam technology based small-scale power plants has been estimated to be about 50 plants in 1992/1993, the total power of which is 220-260 MW. The largest estimate is base situation, in which there would be energy cooperation between the communes and industry. The fuel used by the power plants would be about 5.4-6.6 TWh/a corresponding to 270-330 million FIM/a. The total investment costs of the plants would be about 2.0 billion FIM. The plants would employ about 250 persons, and the fuel supply (wood or peat) about 100 persons

  16. Project Icarus: Exploring Alpha Centauri: Trajectories and Strategies for Subprobe Deployment

    Science.gov (United States)

    Baxter, S.

    2016-06-01

    This paper describes a preliminary study of a long-stay mission to explore the Alpha Centauri system with a fast unmanned probe: that is, an interstellar probe designed to meet the Project Icarus Terms of Reference.

  17. Development of small scale soft x-ray lasers

    International Nuclear Information System (INIS)

    At present rapid progress is being made in the application of soft x-ray lasers to fields such as microscopy and microlithography. A critical factor in the range of suitable applications is the scale and hence cost of the soft x-ray lasers. At Princeton, gain at 183 angstrom has been obtained with relatively low pump laser energies (as low as 6J) in a ''portable'' small-scale soft x-ray laser system. We will also discuss aspects of data interpretation and pitfalls to be avoided in measurements of gain in such systems. 14 refs., 7 figs

  18. Jet Collimation by Small-Scale Magnetic Fields

    OpenAIRE

    Li, Li-Xin

    2001-01-01

    A popular model for jet collimation is associated with the presence of a large-scale and predominantly toroidal magnetic field originating from the central engine (a star, a black hole, or an accretion disk). Besides the problem of how such a large-scale magnetic field is generated, in this model the jet suffers from the fatal long-wave mode kink magnetohydrodynamic instability. In this paper we explore an alternative model: jet collimation by small-scale magnetic fields. These magnetic field...

  19. Development of small scale soft x-ray lasers

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D.; Suckewer, S. (Princeton Univ., NJ (USA). Plasma Physics Lab. Princeton Univ., NJ (USA). Dept. of Mechanical and Aerospace Engineering); Skinner, C.H.; Voorhees, D. (Princeton Univ., NJ (USA). Plasma Physics Lab.)

    1991-05-01

    At present rapid progress is being made in the application of soft x-ray lasers to fields such as microscopy and microlithography. A critical factor in the range of suitable applications is the scale and hence cost of the soft x-ray lasers. At Princeton, gain at 183{angstrom} has been obtained with relatively low pump laser energies (as low as 6J) in a portable'' small-scale soft x-ray laser system. We will also discuss aspects of data interpretation and pitfalls to be avoided in measurements of gain in such systems. 14 refs., 7 figs.

  20. Monitoring the Performance of a Small-Scale Wind Turbine

    OpenAIRE

    Esfahani, Mehdi Lajavardi

    2012-01-01

    ABSTRACT: Small wind turbines are known to generate less than 100 kW of electricity and they are used in farms, homes and small businesses for backup electricity to reduce electricity bills. The present work is concerned with the monitoring of a small scale wind charger which is mounted on the roof of the building of the department of mechanical engineering at Eastern Mediterranean University. Rutland 913 wind charger used for this work has a swept diameter of 910 mm and produces a power out...

  1. Monitoring Results of a Small Scale CHCP System

    OpenAIRE

    Mendes, J. Farinha; Cardoso, João P.; Coelho, Ricardo; Costa, João P.; Fernández, David; Silva, António R.; Morgado, Miguel; Adão, Pedro

    2010-01-01

    A small scale trigeneration system for combined heat, cold and power production was developed and installed at the Laboratório Nacional de Energia e Geologia, I.P. campus in Lisbon, Portugal. This system is one of the twelve experimental trigeneration systems being developed and tested across Europe within the PolySMART project. The CHCP system main constituents are a purpose made CHP prototype with an estimated 27kW maximum heat capacity and 9,6kW maximum electrical capacity and a TDC pro...

  2. Small-scale generator opportunities in the competitive supply market

    International Nuclear Information System (INIS)

    The last franchises for electricity supply held by Public Electricity Suppliers are due to expire early in 1998. As a consequence from then on, after a phased start-up, all electricity consumers will be free to choose their supplier, completing the process of introducing competition into the electricity market which started in 1990 with the privatisation of the Industry. Then the framework by which the industry operates will become very different. This paper will review the changes to the operation of the market and assess the opportunities for small scale embedded generators post 1998. (Author)

  3. ''Flicker'' in small scale laser--plasma self-focusing

    International Nuclear Information System (INIS)

    Small amplitude, short wavelength ion acoustic waves in laser-produced plasmas cause fluctuations in the trajectories of light rays that can lead to time-dependent, self-sustaining shifting of focal spots and a somewhat random redistribution of the light near the critical surface. This flickering is seen in simulations involving small scale beam inhomogeneities over a uniform background laser profile, which model the center of a realistic laser beam. The effect can cause significant intensity multiplication in long scale length high-Z plasmas with only modest beam imperfections

  4. 2012 THIN FILM AND SMALL SCALE MECHANICAL BEHAVIOR GRS/GRC, JULY 21-27, 2012

    Energy Technology Data Exchange (ETDEWEB)

    Balk, Thomas

    2012-07-27

    The mechanical behavior of materials with small dimension(s) is of both fundamental scientific interest and technological relevance. The size effects and novel properties that arise from changes in deformation mechanism have important implications for modern technologies such as thin films for microelectronics and MEMS devices, thermal and tribological coatings, materials for energy production and advanced batteries, etc. The overarching goal of the 2012 Gordon Research Conference on "Thin Film and Small Scale Mechanical Behavior" is to discuss recent studies and future opportunities regarding elastic, plastic and time-dependent deformation, as well as degradation and failure mechanisms such as fatigue, fracture and wear. Specific topics of interest include, but are not limited to: fundamental studies of physical mechanisms governing small-scale mechanical behavior; advances in test techniques for materials at small length scales, such as nanotribology and high-temperature nanoindentation; in-situ mechanical testing and characterization; nanomechanics of battery materials, such as swelling-induced phenomena and chemomechanical behavior; flexible electronics; mechanical properties of graphene and carbon-based materials; mechanical behavior of small-scale biological structures and biomimetic materials. Both experimental and computational work will be included in the oral and poster presentations at this Conference.

  5. Feasibility of small-scale gas engine-based residential cogeneration in Spain

    International Nuclear Information System (INIS)

    Nowadays all countries are developing their own policies to promote cogeneration in the small-scale residential sector. In this paper the feasibility of small-scale gas engine-based residential cogeneration plants under the current Spanish regulation is studied. A unitary thermal load profile is obtained to characterised the thermal demand of residential applications in Spain. This unitary profile is used to analyse the potential of cogeneration in the small-scale range of powers (100-1000 kW). A complete characterisation of the gas fuelled engines in the market is performed and subsequently used to evaluate the economic feasibility within the selected range by means of a self-tailored simulation model. It is underlined how the thermal storage is a crucial element that should be suitably included in a residential cogeneration plant and the distortions that the actual pricing system adds to the profitability of residential plants of different sizes. Finally a sensibility study is carried out in order to evaluate how the Spanish regulation is able to deal with future variations in the energy prices. It is shown that a rise in the price of the natural gas increases the current feasibility of a plant while a decrease descends the profitability. - Highlights: → Profitability is obtained within the whole small-scale range of powers. → The stepped structure of prices strongly affect the feasibility of the projects. → The inclusion of thermal storage notably affects the profitability of the plant. → Big chance for increase the feasibility exists in retrofitting old installations. → The system of tariff updating balances the future variations in the price of fuels.

  6. Preliminary Scaling Estimate for Select Small Scale Mixing Demonstration Tests

    Energy Technology Data Exchange (ETDEWEB)

    Wells, Beric E.; Fort, James A.; Gauglitz, Phillip A.; Rector, David R.; Schonewill, Philip P.

    2013-09-12

    The Hanford Site double-shell tank (DST) system provides the staging location for waste that will be transferred to the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Specific WTP acceptance criteria for waste feed delivery describe the physical and chemical characteristics of the waste that must be met before the waste is transferred from the DSTs to the WTP. One of the more challenging requirements relates to the sampling and characterization of the undissolved solids (UDS) in a waste feed DST because the waste contains solid particles that settle and their concentration and relative proportion can change during the transfer of the waste in individual batches. A key uncertainty in the waste feed delivery system is the potential variation in UDS transferred in individual batches in comparison to an initial sample used for evaluating the acceptance criteria. To address this uncertainty, a number of small-scale mixing tests have been conducted as part of Washington River Protection Solutions’ Small Scale Mixing Demonstration (SSMD) project to determine the performance of the DST mixing and sampling systems.

  7. Small-Scale Conformity of the Virgo Cluster Galaxies

    CERN Document Server

    Lee, Hye-Ran; Jeong, Hyunjin; Park, Byeong-Gon

    2016-01-01

    We investigate the small-scale conformity in color between bright galaxies and their faint companions in the Virgo cluster. Cluster member galaxies are spectroscopically determined using the Extended Virgo Cluster Catalog (EVCC) and the Sloan Digital Sky Survey Data Release 12 (SDSS DR12). We find that the luminosity-weighted mean color of faint galaxies depends on the color of adjacent bright galaxy as well as on the cluster-scale environment (gravitational potential index). From this result for the entire area of the Virgo cluster, it is not distinguishable whether the small-scale conformity is genuine or is artificially produced due to cluster-scale variation of galaxy color. To disentangle this degeneracy, we divide the Virgo cluster area into three sub-areas so that the cluster-scale environmental dependence is minimized: A1 (central), A2 (intermediate) and A3 (outermost). We find conformity in color between bright galaxies and their faint companions (color-color slope significance S ~ 2.73 sigma and cor...

  8. A small-scale anatomical dosimetry model of the liver

    International Nuclear Information System (INIS)

    Radionuclide therapy is a growing and promising approach for treating and prolonging the lives of patients with cancer. For therapies where high activities are administered, the liver can become a dose-limiting organ; often with a complex, non-uniform activity distribution and resulting non-uniform absorbed-dose distribution. This paper therefore presents a small-scale dosimetry model for various source–target combinations within the human liver microarchitecture. Using Monte Carlo simulations, Medical Internal Radiation Dose formalism-compatible specific absorbed fractions were calculated for monoenergetic electrons; photons; alpha particles; and 125I, 90Y, 211At, 99mTc, 111In, 177Lu, 131I and 18F. S values and the ratio of local absorbed dose to the whole-organ average absorbed dose was calculated, enabling a transformation of dosimetry calculations from macro- to microstructure level. For heterogeneous activity distributions, for example uptake in Kupffer cells of radionuclides emitting low-energy electrons (125I) or high-LET alpha particles (211At) the target absorbed dose for the part of the space of Disse, closest to the source, was more than eight- and five-fold the average absorbed dose to the liver, respectively. With the increasing interest in radionuclide therapy of the liver, the presented model is an applicable tool for small-scale liver dosimetry in order to study detailed dose–effect relationships in the liver. (paper)

  9. Small-Scale Smart Grid Construction and Analysis

    Science.gov (United States)

    Surface, Nicholas James

    The smart grid (SG) is a commonly used catch-phrase in the energy industry yet there is no universally accepted definition. The objectives and most useful concepts have been investigated extensively in economic, environmental and engineering research by applying statistical knowledge and established theories to develop simulations without constructing physical models. In this study, a small-scale version (SSSG) is constructed to physically represent these ideas so they can be evaluated. Results of construction show data acquisition three times more expensive than the grid itself although mainly due to the incapability to downsize 70% of data acquisition costs to small-scale. Experimentation on the fully assembled grid exposes the limitations of low cost modified sine wave power, significant enough to recommend pure sine wave investment in future SSSG iterations. Findings can be projected to full-size SG at a ratio of 1:10, based on the appliance representing average US household peak daily load. However this exposes disproportionalities in the SSSG compared with previous SG investigations and recommended changes for future iterations are established to remedy this issue. Also discussed are other ideas investigated in the literature and their suitability for SSSG incorporation. It is highly recommended to develop a user-friendly bidirectional charger to more accurately represent vehicle-to-grid (V2G) infrastructure. Smart homes, BEV swap stations and pumped hydroelectric storage can also be researched on future iterations of the SSSG.

  10. Small-scale Rainfall Challenges Tested with Semi-distributed and Distributed Hydrological Models

    Science.gov (United States)

    Ichiba, Abdellah; Tchiguirinskaia, Ioulia; Gires, Auguste; Schertzer, Daniel; Bompard, Philippe

    2016-04-01

    -France C-band radar data at 1km pixel scale and (3) ENPC X-band dual polarization radar data at 250m pixel scale. Results show that considering bigger number of smaller sub-catchments improve the response of CANOE model to small-scale rainfall. However, the fully distributed approach demonstrates much higher sensitivity than the semi-distributed one, suggesting that this approach is more appropriate to integrate the rainfall structures measured at small scales. Finally, we compare these results with those obtained earlier in the framework of the RainGain project (www.raingain.eu), which helps to re-interpret some of our former conclusions.

  11. Exergoeconomic analysis of small-scale biomass steam cogeneration

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Sotomonte, Cesar Adolfo; Lora, Electo Eduardo Silva [Universidade Federal de Itajuba, MG (Brazil)], e-mails: c.rodriguez32@unifei.edu.br, electo@unifei.edu.br; Venturini, Osvaldo Jose; Escobar, Jose Carlos [Universidad Federal de Itajuba, MG (Brazil)], e-mail: osvaldo@unifei.edu.br

    2010-07-01

    The principal objective of this work is to develop a calculation process, based on the second law of thermodynamics, for evaluating the thermoeconomic potential of a small steam cogeneration plant using waste from pulp processing and/or sawmills as fuel. Four different configurations are presented and assessed. The exergetic efficiency of the cycles that use condensing turbines is found to be around 11%, which has almost 3 percent higher efficiency than cycles with back pressure turbines. The thermoeconomic equations used in this paper estimated the production costs varying the fuel price. The main results show that present cost of technologies in a small-scale steam cycle cogeneration do not justify the implementation of more efficient systems for biomass prices less than 100 R$/t. (author)

  12. Modelling Relativistic Astrophysics at the Large and Small Scale

    CERN Document Server

    Haugbölle, T

    2005-01-01

    In this thesis different numerical methods, as well as applications of the methods to a number of current problems in relativistic astrophysics, are presented. In the first part the theoretical foundation and numerical implementation of a new general relativistic magnetohydrodynamics code is discussed. A new form of the equations of motion using global coordinates, but evolving the dynamical variables from the point of view of a local observer is presented. No assumptions are made about the background metric and the design is ready to be coupled with methods solving the full Einstein equations. In the second part of the thesis important results concerning the understanding of collisionless shocks, obtained from experiments with a relativistic charged particle code, are presented. Relativistic collisionless shocks are important in a range of astrophysical objects; in particular in gamma ray burst afterglows and other relativistic jets. It is shown that a strong small scale, fluctuating, and predominantly trans...

  13. The small-scale turbulent dynamo in smoothed particle magnetohydrodynamics

    CERN Document Server

    Tricco, Terrence S; Federrath, Christoph

    2016-01-01

    Supersonic turbulence is believed to be at the heart of star formation. We have performed smoothed particle magnetohydrodynamics (SPMHD) simulations of the small-scale dynamo amplification of magnetic fields in supersonic turbulence. The calculations use isothermal gas driven at rms velocity of Mach 10 so that conditions are representative of star-forming molecular clouds in the Milky Way. The growth of magnetic energy is followed for 10 orders in magnitude until it reaches saturation, a few percent of the kinetic energy. The results of our dynamo calculations are compared with results from grid-based methods, finding excellent agreement on their statistics and their qualitative behaviour. The simulations utilise the latest algorithmic developments we have developed, in particular, a new divergence cleaning approach to maintain the solenoidal constraint on the magnetic field and a method to reduce the numerical dissipation of the magnetic shock capturing scheme. We demonstrate that our divergence cleaning met...

  14. Using dark energy to suppress power at small scales

    CERN Document Server

    Kunz, Martin; Sawicki, Ignacy

    2015-01-01

    The latest Planck results reconfirm the existence of a slight but chronic tension between the best-fit CMB and low-redshift observables: power seems to be consistently lacking in the late universe across a range of observables (e.g. weak lensing, cluster counts). We propose a two-parameter model for dark energy where the dark energy is sufficiently like dark matter at large scales to keep the CMB unchanged but where it does not cluster at small scales, preventing concordance collapse and erasing power. We thus exploit the generic scale-dependence of DE instead of the more usual time-dependence to address the tension in the data. The combination of CMB, distance and weak lensing data somewhat prefer our model to $\\Lambda$CDM, at $\\Delta\\chi^2=2.4$. Moreover, this improved solution has $\\sigma_8=0.79 \\pm 0.02$, consistent with the value implied by cluster counts.

  15. Small-scale power/heat production based on biomass

    International Nuclear Information System (INIS)

    Conventional energy production from biomass is most often used to produce steam, hot water or air heating. According to this conference paper, the maximum electric output is obtained in processes based on gasification of biomass in combined gas turbine/steam turbine systems. The efficiency increases with increasing plant size. Production cost decreases with increasing plant size. However, large plants producing 20 MW electric also produce 30 MW heat energy which must be utilized if the total efficiency is to be large. There is a potential for small systems (3 - 5 kw electric) for decentralized power/heat production. The paper surveys in brief various technologies for small-scale power/heat plants based on biomass: steam turbine, steam engine, gas turbine, Stirling engine, diesel engine/gas engine. 9 refs., 5 figs

  16. Burn-rate Measurement on Small-scale Rocket Motors

    Directory of Open Access Journals (Sweden)

    F. Maggi

    2006-07-01

    Full Text Available Small-scale rocket motors are widely used by propulsion industries to carry out burn ratemeasurement for a variety of needs. Several automated data-reduction procedures have beenimplemented to derive burn rate from pressure-time profiles resulting from experimentation. Evenif these are easy and fast to use, these procedures are not completely reliable in that thesemeasure only the average behaviour of a motor. A new model has recently been proposed toovercome this problem. However, it was soon noticed that the results depend on the propellantgrain production and forming processes even if the motor hardware is the same. A series ofpropellant grains has been produced to be sampled to map the local ballistic behaviour andchanges introduced by the manufacturing process. In this study, sampling and testing proceduresare reported and the results of an almost complete grain mapping are discussed.

  17. Stability of small-scale baryon perturbations during cosmological recombination

    CERN Document Server

    Venumadhav, Tejaswi

    2014-01-01

    In this paper, we study small-scale fluctuations (baryon pressure sound waves) in the baryon fluid during recombination. In particular, we look at their evolution in the presence of relative velocities between baryons and photons on large scales ($k \\sim 10^{-1} \\ {\\rm Mpc}^{-1}$), which are naturally present during the era of decoupling. Previous work concluded that the fluctuations grow due to an instability of sound waves in a recombining plasma, but that the growth factor is small for typical cosmological models. These analyses model recombination in an inhomogenous universe as a perturbation to the parameters of the homogenous solution. We show that for relevant wavenumbers $k\\gtrsim 10^3\\ {\\rm Mpc}^{-1}$ the dynamics are significantly altered by the transport of both ionizing continuum ($h\

  18. Manufacture of a Biodegradable Detergent on Small Scale

    Directory of Open Access Journals (Sweden)

    Abdulla A. Aziz A. Majeed

    2010-12-01

    Full Text Available This paper deals with an aggregate planning for a small scale production unit using a network flow model for full utilization of its capacity to meet the changing forecasted demand .The formulation of the problem is done by using the given inventory capacity with backorders by making a trade-off among inventory costs , backlog costs, production and subcontracting costs. The total cost function and the constraint inequalities were developed assuming the cost functions to be linear. The parameters of objective function and the constraints were estimated from the economics of the plant. The values of the work force, overtime, backlog, amount subcontracted were determined for a planning horizon of six months using an LP computer package. This method of production scheduling took care of the fluctuating demand utilizing the full capacity of the plant.

  19. Small scale wind energy harvesting with maximum power tracking

    Directory of Open Access Journals (Sweden)

    Joaquim Azevedo

    2015-07-01

    Full Text Available It is well-known that energy harvesting from wind can be used to power remote monitoring systems. There are several studies that use wind energy in small-scale systems, mainly with wind turbine vertical axis. However, there are very few studies with actual implementations of small wind turbines. This paper compares the performance of horizontal and vertical axis wind turbines for energy harvesting on wireless sensor network applications. The problem with the use of wind energy is that most of the time the wind speed is very low, especially at urban areas. Therefore, this work includes a study on the wind speed distribution in an urban environment and proposes a controller to maximize the energy transfer to the storage systems. The generated power is evaluated by simulation and experimentally for different load and wind conditions. The results demonstrate the increase in efficiency of wind generators that use maximum power transfer tracking, even at low wind speeds.

  20. Large and small scale MHD mode studies at TEXTOR

    International Nuclear Information System (INIS)

    The 3D-reconstruction of large m = 2 modes and their evolution have been analysed, as well as their electron temperature profiles and heat transport properties with respect to the background plasma. The confinement is improved within the magnetic island, compared to the background plasma as evidenced by a secondary temperature maximum at the centre of the island. Using cross-correlation between different ECE channels, temperature fluctuations in the presence of magnetic islands are investigated. For m = 2 islands, they are larger in the vicinity of the X-point than in the O-point. Evidence of high m-number small-scale modes in the q = 2 vicinity is obtained. (authors)

  1. Design and Modelling of Small Scale Low Temperature Power Cycles

    DEFF Research Database (Denmark)

    Wronski, Jorrit

    . The accelerated property evaluation by means of table-based interpolation was shown to be up to 120 times faster than solving the full equation of state (EOS) for enthalpy and pressure as inputs, which enhanced the simulation experience significantly while keeping the associated relative error below...... 10−4 at all times and below 10−7 away from the phase boundaries.Regarding expansion devices for small scale organic Rankine cycle (ORC) systems,this work focussed on reciprocating machines. A prototype of a reciprocating expander with a swept volume of 736 cm3 was tested and modelled. he model was...... condenser conditions was found to be suitable for an optimisation of the expander operation. During the experiments,the machine ran with n-pentane as working fluid and delivered up to 2.5 kW of shaft power. Operating with variable admission valve timing, the expander exhibited a stable isentropic effciency...

  2. Economic feasibility of small scale button mushroom production in pakistan

    International Nuclear Information System (INIS)

    Abstract:- Mushroom is widely cultivated as a proteineous vegetable in many countries of the world including Pakistan. Its cultivation requires less space, care, equipment and cost compared to many other crops and livestock. The present study was conducted in 2010 to estimate the profitability of small scale button mushroom production at National Agricultural Research Centre (NARC) Islamabad, Pakistan. The cost of production methodology was used for this study. The yield and gross return of mushroom was estimated at 155.6 kg ha and Rs.77,800 ha , respectively. The results indicated the fact that mushroom production is very much remunerative to its producers as it can give maximum net return by reducing their cost of production as its cultivation is dependent on the agricultural raw material which is cheaply available. (author)

  3. Optimal Combustion Conditions for a Small-scale Biomass Boiler

    Directory of Open Access Journals (Sweden)

    Viktor Plaček

    2012-01-01

    Full Text Available This paper reports on an attempt to achieve maximum efficiency and lowest possible emissions for a small-scale biomass boiler. This aim can be attained only by changing the control algorithm of the boiler, and in this way not raising the acquisition costs for the boiler. This paper describes the experimental facility, the problems that arose while establishing the facility, and how we have dealt with them. The focus is on discontinuities arising after periodic grate sweeping, and on finding the parameters of the PID control loops. Alongside these methods, which need a lambda probe signal for proper functionality, we inroduce another method, which is able to intercept the optimal combustion working point without the need to use a lambda sensor.

  4. Numerical simulation of small scale soft impact tests

    Energy Technology Data Exchange (ETDEWEB)

    Varpasuo, Pentti [Fortum Nuclear Services Ltd. P.O. Box 10, 00048 Fortum (Finland)

    2008-07-01

    This paper describes the small scale soft missile impact tests. The purpose of the test program is to provide data for the calibration of the numerical simulation models for impact simulation. In the experiments, both dry and fluid filled missiles are used. The tests with fluid filled missiles investigate the release speed and the droplet size of the fluid release. This data is important in quantifying the fire hazard of flammable liquid after the release. The spray release velocity and droplet size are also input data for analytical and numerical simulation of the liquid spread in the impact. The behaviour of the impact target is the second investigative goal of the test program. The response of reinforced and pre-stressed concrete walls is studied with the aid of displacement and strain monitoring. (authors)

  5. Numerical simulation of small scale soft impact tests

    International Nuclear Information System (INIS)

    This paper describes the small scale soft missile impact tests. The purpose of the test program is to provide data for the calibration of the numerical simulation models for impact simulation. In the experiments, both dry and fluid filled missiles are used. The tests with fluid filled missiles investigate the release speed and the droplet size of the fluid release. This data is important in quantifying the fire hazard of flammable liquid after the release. The spray release velocity and droplet size are also input data for analytical and numerical simulation of the liquid spread in the impact. The behaviour of the impact target is the second investigative goal of the test program. The response of reinforced and pre-stressed concrete walls is studied with the aid of displacement and strain monitoring. (authors)

  6. Emissions from small scale combustion of pelletized wood fuels

    International Nuclear Information System (INIS)

    Combustion of wood pellets in small scale heating systems with an effect below 20 kW has increased. During the winter season 1995/96 1500 small plants for heating houses are estimated to be in operation. Stack emissions from three pellet burners and two pellet stoves have been studied at laboratory. Different pellet qualities were tested. When the fraction of fines increased also the NOx emissions increased with about 10 %. As reference fuel 8 mm pellets was used. Tests with 6 mm pellets gave, in most cases, significant lower emissions of CO and THC. Eleven stoves, burners and boilers were studied in a field test. The results show that all the plants generally have higher emissions in the field than during conditions when the plants are adjusted with a stack gas monitoring instrument. A conclusion is that it is difficult for the operator to adjust the plant without a monitoring instrument. The emissions from the tested plants give an estimation of stack gas emissions from small scale pellet plants. The difference between the 'best' and 'worst' technologies is big. The span of emissions with the best technology to the worst is given below. The interval is concerning normal combustion . During abnormal conditions the emissions are on a significant higher level: * CO 80-1 000 mg/MJ; * Tar 0,3-19 mg/MJ; * THC (as methane equivalents) 2-100 mg/MJ; * NOx 50-70 mg/W;, and * Dust emissions 20-40 mg/MJ. Emissions from pellets heating are lower than from wood combustion and the best technology is close to the emission from oil burners. Wood and pellets have the same origin but the conditions to burn them in an environmental friendly way differ. Combustion of pellets could be improved through improved control of the air and fuel ratio that will create more stable conditions for the combustion

  7. Increasing the contribution of small-scale fisheries to poverty alleviation and food security

    OpenAIRE

    Bolan, Tom

    2005-01-01

    The objectives of these Technical Guidelines are to provide a focus on small-scale fisheries and their current and potential role in contributing to poverty alleviation and food security by expanding on the guidance on small-scale fisheries offered by the Code. The Guidelines are complementary to existing Technical Guidelines for Responsible Fisheries. Most small-scale fishers are in developing countries and many live in communities characterized by poverty and food insecurity. Small-scale f...

  8. Long-term Stability of Planets in the Centauri System

    Science.gov (United States)

    Quarles, B.; Lissauer, Jack J.

    2016-05-01

    We evaluate the extent of the regions within the α Centauri AB star system where small planets are able to orbit for billion-year timescales, and we calculate the positions on the sky plane where planets on stable orbits about either stellar component may appear. We confirm the qualitative results of Wiegert and Holman (AJ 113, 1445, 1997) regarding the approximate size of the regions of stable orbits, which are larger for retrograde orbits relative to the binary than for prograde orbits. Additionally, we find that mean motion resonances with the binary orbit leave an imprint on the limits of orbital stability, and the effects of the Lidov-Kozai mechanism are also readily apparent.

  9. Ultraviolet variability of the solar analogue star Alpha Centauri A

    International Nuclear Information System (INIS)

    Fifty-seven observations of the solar analogue Alpha Centauri A made by the International Ultraviolet Explorer over a 3-year interval have been examined for variability. The authors find that the ultraviolet continuum flux of this star in the 1,715-1,915-angstrom range varies by as much as 19% (with a standard deviation of ± 1.3%). However, nearly all of this range in variability can occur within one stellar rotation period. Consequently, if Alpha Cen A undergoes a stellar activity cycle similar to that of the Sun, the results indicate that the amplitude of this modulation is small, contrary to recently proposed empirical (theoretical) models of solar activity

  10. The Stability of Planets in the Alpha Centauri system

    CERN Document Server

    Wiegert, P A; Wiegert, Paul A.; Holman, Matt

    1996-01-01

    This paper investigates the long-term orbital stability of small bodies near the central binary of the Alpha Centauri system. Test particles on circular orbits are integrated in the field of this binary for 32000 binary periods or approximately 2.5 Myr. In the region exterior to the binary, particles with semi-major axes less than roughly three times the binary's semi-major axis are unstable. Inside the binary, particles are unstable if further than 0.2 binary semimajor axes from the primary, with stablility closer in a strong function of inclination: orbits inclined near 90 degrees are unstable in as close as 0.01 binary semimajor axes from either star.

  11. Prospects for Characterizing the Atmosphere of Proxima Centauri b

    CERN Document Server

    Kreidberg, Laura

    2016-01-01

    The newly detected Earth-mass planet in the habitable zone of Proxima Centauri could potentially host life - if it has an atmosphere that supports surface liquid water. We show that thermal phase curve observations with the James Webb Space Telescope (JWST) from 5-12 microns can be used to test the existence of such an atmosphere. We predict the thermal variation for a bare rock versus a planet with 35% heat redistribution to the nightside and show that a JWST phase curve measurement can distinguish between these cases at $5\\sigma$ confidence. We also consider the case of an Earth-like atmosphere, and find that the ozone 9.8 micron band could be detected with longer integration times (a few months). We conclude that JWST observations have the potential to put the first constraints on the possibility of life around the nearest star to the Solar System.

  12. A Niche for Small-Scale Farmers: Report of a Five-State Survey.

    Science.gov (United States)

    Young, John A.

    This paper reports on a survey of 221 small-scale farmers conducted in 5 western states. Despite the current productive dominance of large farms, an argument can be made that small-scale farming is desirable both for social and ecological reasons. Discussion focuses on the tradition-oriented goals and values of small-scale farmers, special…

  13. 77 FR 68104 - Proposed Information Collection; Comment Request; Socio-Economic Profile of Small-Scale...

    Science.gov (United States)

    2012-11-15

    ...-economic performance of small- scale fleets, and evaluate the socio-economic impacts of Federal regulatory...-Economic Profile of Small-Scale Commercial Fisheries in the U.S. Caribbean AGENCY: National Oceanic and... socio-economic data about small scale fishermen and seafood dealers operating in the U.S. Caribbean....

  14. Investigation of the feasibility of a small scale transmutation device

    Science.gov (United States)

    Sit, Roger Carson

    This dissertation presents the design and feasibility of a small-scale, fusion-based transmutation device incorporating a commercially available neutron generator. It also presents the design features necessary to optimize the device and render it practical for the transmutation of selected long-lived fission products and actinides. Four conceptual designs of a transmutation device were used to study the transformation of seven radionuclides: long-lived fission products (Tc-99 and I-129), short-lived fission products (Cs-137 and Sr-90), and selective actinides (Am-241, Pu-238, and Pu-239). These radionuclides were chosen because they are major components of spent nuclear fuel and also because they exist as legacy sources that are being stored pending a decision regarding their ultimate disposition. The four designs include the use of two different devices; a Deuterium-Deuterium (D-D) neutron generator (for one design) and a Deuterium-Tritium (D-T) neutron generator (for three designs) in configurations which provide different neutron energy spectra for targeting the radionuclide for transmutation. Key parameters analyzed include total fluence and flux requirements; transmutation effectiveness measured as irradiation effective half-life; and activation products generated along with their characteristics: activity, dose rate, decay, and ingestion and inhalation radiotoxicity. From this investigation, conclusions were drawn about the feasibility of the device, the design and technology enhancements that would be required to make transmutation practical, the most beneficial design for each radionuclide, the consequence of the transmutation, and radiation protection issues that are important for the conceptual design of the transmutation device. Key conclusions from this investigation include: (1) the transmutation of long-lived fission products and select actinides can be practical using a small-scale, fusion driven transmutation device; (2) the transmutation of long

  15. Small-scale volcanoes on Mars: distribution and types

    Science.gov (United States)

    Broz, Petr; Hauber, Ernst

    2015-04-01

    Volcanoes differ in sizes, as does the amount of magma which ascends to a planetary surface. On Earth, the size of volcanoes is anti-correlated with their frequency, i.e. small volcanoes are much more numerous than large ones. The most common terrestrial volcanoes are scoria cones (Nepenthes/Amenthes region, Arena Colles and inside Lederberg crater), and alternative interpretations (mud volcanoes) seem possible. Other relatively rare volcanoes seem to be lava domes, reported only from two regions (Acracida Planitia and Terra Sirenum). On the other hand, small shields and rootless cones (which are not primary volcanic landforms) represent widely spread phenomena recognized in Tharsis and Elysium. Based on these new observations, the distribution of small volcanoes on Mars seems to be much more widespread than anticipated a decade ago. There are sometimes significant differences in the final morphologies between Martian hypothesized and possible terrestrial analogs, despite fact that the physical processes behind volcano formation should be similar on both planets. For example, Martian scoria cones are ~2.6 times wider than terrestrial analogues, as lower gravity and atmospheric pressure enable wider dispersion of pyroclasts from the vent. In addition, exit velocities of ejected particles should be increased on Mars because the lower atmospheric pressure favors more rapid exsolution of dissolved gases from the magma, which also favors a wider dispersion of ejected particles. Therefore, care must be taken when applying terrestrial morphometric relationships to the interpretation of hypothesized volcanic features on Mars and other terrestrial bodies. As on Earth, small-scale volcanoes on Mars display diverse shapes and hence provide insight into diverse volcanic processes responsible for such variations. Those diverse processes may point to various mechanisms of magma ascent and eruption styles in dependency on magma properties (e.g., amount of volatiles) and the paleo

  16. Small-Scale Spray Releases: Additional Aerosol Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Schonewill, Philip P.; Gauglitz, Phillip A.; Kimura, Marcia L.; Brown, G. N.; Mahoney, Lenna A.; Tran, Diana N.; Burns, Carolyn A.; Kurath, Dean E.

    2013-08-01

    One of the events postulated in the hazard analysis at the Waste Treatment and Immobilization Plant (WTP) and other U.S. Department of Energy (DOE) nuclear facilities is a breach in process piping that produces aerosols with droplet sizes in the respirable range. The current approach for predicting the size and concentration of aerosols produced in a spray leak involves extrapolating from correlations reported in the literature. These correlations are based on results obtained from small engineered spray nozzles using pure liquids with Newtonian fluid behavior. The narrow ranges of physical properties on which the correlations are based do not cover the wide range of slurries and viscous materials that will be processed in the WTP and across processing facilities in the DOE complex. To expand the data set upon which the WTP accident and safety analyses were based, an aerosol spray leak testing program was conducted by Pacific Northwest National Laboratory (PNNL). PNNL’s test program addressed two key technical areas to improve the WTP methodology (Larson and Allen 2010). The first technical area was to quantify the role of slurry particles in small breaches where slurry particles may plug the hole and prevent high-pressure sprays. The results from an effort to address this first technical area can be found in Mahoney et al. (2012a). The second technical area was to determine aerosol droplet size distribution and total droplet volume from prototypic breaches and fluids, including sprays from larger breaches and sprays of slurries for which literature data are largely absent. To address the second technical area, the testing program collected aerosol generation data at two scales, commonly referred to as small-scale and large-scale. The small-scale testing and resultant data are described in Mahoney et al. (2012b) and the large-scale testing and resultant data are presented in Schonewill et al. (2012). In tests at both scales, simulants were used to mimic the

  17. Analysis of Value Chain Governance: Scenarios to Develop Small-Scale Furniture Producers

    Directory of Open Access Journals (Sweden)

    Rika Harini Irawati

    2011-05-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Furniture industry had shown a long chain of production to consumption, from raw material producers (tree growers, semi-finished producers, finished product producers, and retailers to exporters. Jepara as a centre furniture industry in Indonesia incorporates around 15,000 business units and provide livelihoods to approximately 170,000 workers. This sector contributes about 27% of Jepara‘s people domestic income. Small and medium furniture enterprises (SMEs have significant roles in the furniture industry as production structures are characterized by them. Power and information imbalance throughout the furniture value chain have resulted in problems of uneven distribution of gains among actors of the industry. SME furniture producers have experienced an unfair value added distribution. Hence, development of SMEs is important for strengthening the industry and expected to result in a portion of value added distribution to them.  We are trying to develop scenarios for SME improvement in the furniture industry in Jepara by identifying their problems and implementing Value Chain Analysis (VCA. VCA is an approach to describe SME producer relations with other actors in the industry and the governance type of their relations. Data is collected by interviewing selected SMEs from the association of small scale producers in Jepara to get detailed maps of their value chain. The research will produce future scenarios and intervention points to improve small-scale producer sustainability and better value added distribution among furniture actors. The scenarios will not only benefit selected producers but also the furniture industry of Jepara, and can be adopted for similar industries throughout Indonesia and abroad. Keywords: furniture, value chain, governance, scenario, small-scale

  18. Calculations of periodicity from H{\\alpha} profiles of Proxima Centauri

    CERN Document Server

    Collins, John M; Barnes, John R

    2016-01-01

    We investigate retrieval of the stellar rotation signal for Proxima Centauri. We make use of high-resolution spectra taken with uves and harps of Proxima Centauri over a 13-year period as well as photometric observations of Proxima Centauri from asas and hst. We measure the H{\\alpha} equivalent width and H{\\alpha} index, skewness and kurtosis and introduce a method that investigates the symmetry of the line, the Peak Ratio, which appears to return better results than the other measurements. Our investigations return a most significant period of 82.6 $\\pm$ 0.1 days, confirming earlier photometric results and ruling out a more recent result of 116.6 days which we conclude to be an alias induced by the specific harps observation times. We conclude that whilst spectroscopic H{\\alpha} measurements can be used for period recovery, in the case of Proxima Centauri the available photometric measurements are more reliable. We make 2D models of Proxima Centauri to generate simulated H{\\alpha}, finding that reasonable di...

  19. Small Scale Evaporation Kinetics of a Binary Fluid Mixture

    Science.gov (United States)

    Basdeo, Carl; Ye, Dezhuang; Kalonia, Devendra; Fan, Tai-Hsi; Mechanical Engineering Team; Pharmaceutical Sciences Collaboration

    2013-03-01

    Evaporation induces a concentrating effect in liquid mixtures. The transient process has significant influence on the dynamic behaviors of a complex fluid. To simultaneously investigate the fluid properties and small-scale evaporation kinetics during the transient process, the quartz crystal microbalance is applied to a binary mixture droplet of light alcohols including both a single volatile component (a fast evaporation followed by a slow evaporation) and a mixture of two volatile components with comparable evaporation rates. The density and viscosity stratification are evaluated by the shear wave, and the evaporation kinetics is measured by the resonant signature of the acoustic p-wave. The evaporation flux can be precisely determined by the resonant frequency spikes and the complex impedance. To predict the concentration field, the moving interface, and the precision evaporation kinetics of the mixture, a multiphase model is developed to interpret the complex impedance signals based on the underlying mass and momentum transport phenomena. The experimental method and theoretical model are developed for better characterizing and understanding of the drying process involving liquid mixtures of protein pharmaceuticals.

  20. Small Scale Parallel Manipulator Kinematics for Flexible Snake Robot Application

    Directory of Open Access Journals (Sweden)

    Raisuddin Khan

    2014-01-01

    Full Text Available A small-scale parallel manipulator is designed in this paper. The kinematic analysis of the manipulator is also elucidated for the development of multilinked snake robot. A compliant central colum is used to connect two parallel platforms of Incompletely Restrained Positioning Mechanism (IRPM. The compliant column allows the configuration to achieve 3 DOFs with 3 tendons of active materials connected between the upper and loer platform of the mechanism. In particular, this investigation focuses on the angular deflection of the upper platform with respect to the lower platform. The application here is aimed at developing an active linkable module that can be connected to one another so as to form a “snake robot” of sorts. For an arbitrary angular displacement of the platforms, the corresponding length of each tendon can be determined through inverse kinematics. From the experimental result, the extreme bending of the central column plane of 30° angular displacement with the of the horizontal axis.

  1. The small-scale turbulent dynamo in smoothed particle magnetohydrodynamics

    Science.gov (United States)

    Tricco, T. S.; Price, D. J.; Federrath, C.

    2016-05-01

    Supersonic turbulence is believed to be at the heart of star formation. We have performed smoothed particle magnetohydrodynamics (SPMHD) simulations of the small- scale dynamo amplification of magnetic fields in supersonic turbulence. The calculations use isothermal gas driven at rms velocity of Mach 10 so that conditions are representative of starforming molecular clouds in the Milky Way. The growth of magnetic energy is followed for 10 orders in magnitude until it reaches saturation, a few percent of the kinetic energy. The results of our dynamo calculations are compared with results from grid-based methods, finding excellent agreement on their statistics and their qualitative behaviour. The simulations utilise the latest algorithmic developments we have developed, in particular, a new divergence cleaning approach to maintain the solenoidal constraint on the magnetic field and a method to reduce the numerical dissipation of the magnetic shock capturing scheme. We demonstrate that our divergence cleaning method may be used to achieve ∇ • B = 0 to machine precision, albeit at significant computational expense.

  2. Development of a small-scale computer cluster

    Science.gov (United States)

    Wilhelm, Jay; Smith, Justin T.; Smith, James E.

    2008-04-01

    An increase in demand for computing power in academia has necessitated the need for high performance machines. Computing power of a single processor has been steadily increasing, but lags behind the demand for fast simulations. Since a single processor has hard limits to its performance, a cluster of computers can have the ability to multiply the performance of a single computer with the proper software. Cluster computing has therefore become a much sought after technology. Typical desktop computers could be used for cluster computing, but are not intended for constant full speed operation and take up more space than rack mount servers. Specialty computers that are designed to be used in clusters meet high availability and space requirements, but can be costly. A market segment exists where custom built desktop computers can be arranged in a rack mount situation, gaining the space saving of traditional rack mount computers while remaining cost effective. To explore these possibilities, an experiment was performed to develop a computing cluster using desktop components for the purpose of decreasing computation time of advanced simulations. This study indicates that small-scale cluster can be built from off-the-shelf components which multiplies the performance of a single desktop machine, while minimizing occupied space and still remaining cost effective.

  3. Development of the Small Scale Violence Thermal Test

    Science.gov (United States)

    Sorber, Susan

    2011-06-01

    When developing new explosive formulations, one of the most important safety goals is to characterise the formulations' scale of response to thermal insults. Established tests provide indications of violence of response from thermal stimuli through dent/fragment analysis of heater anvils and visual observations. Utilising recent advances in diagnostic technologies, a test is under development to obtain a numerical value for the violence of response to thermal stimuli on a small explosive sample. Furthermore, the test has been designed so that it can accept pressed explosive pellets. This enables the test to be conducted at the small-scale development stage and thus is anticipated to be if use in the screening of new materials. In continuation of previously published work describing the test development, twenty-seven new cook-off experiments have been conducted. Eleven explosive compositions were subjected to the same slow heat input profile. As a sample rapidly decomposed, part of the steel confinement was designed to produce a pellet whose velocity was measured using a Heterodyne Velocimeter (Het-V). Temperatures of the confinement unit were also recorded. A development aim is to interpret this data to provide useful information on the violence of decomposition. This is discussed in the paper and leads to the data from these experiments being presented in order of increasing violence of response.

  4. Social and Ecological Dynamics of Small-Scale Fisheries

    Science.gov (United States)

    Stevens, K.; Kramer, D.; Frank, K.

    2012-12-01

    Globalization's reach is rapidly extending to touch some of the most remote communities of the world, but we have yet to understand its scale and impact. On Nicaragua's previously remote Miskitu Coast, the introduction of new markets and global demand for seafood has resulted in changes in fishermen's harvest behavior manifested within the local fishery. Small-scale fisheries are a significant component in sustaining global fish trade, ensuring food security, and alleviating poverty, but because the fishermen are disperse, numerous and located in remote areas, the social and ecological dynamics of the system are poorly understood. Previous work has indicated a decline in fish abundance as a result of connection to markets, yet fishermen's response to this decline and the resulting shift in harvest strategy requires further examination. I identify the ecological and social factors that explain changes in fishermen behavior and use an innovative application of social network analysis to understand these changes. I also use interviews with fishermen and fishery-dependent surveys to measure catch and release behavior and seasonal gear use. Results demonstrate multiple cliques within a community that mitigate the response of fishermen to changes in the fishery. This research applies techniques in social science to address challenges in sustainable management of fisheries. As fisheries managers consider implementing new regulations, such as seasonal restrictions on gear, it is essential to understand not just how this might impact fish abundance, but how and why human systems respond as they do.

  5. Social Norms of Cooperation in Small-Scale Societies

    Science.gov (United States)

    Santos, Fernando P.; Santos, Francisco C.; Pacheco, Jorge M.

    2016-01-01

    Indirect reciprocity, besides providing a convenient framework to address the evolution of moral systems, offers a simple and plausible explanation for the prevalence of cooperation among unrelated individuals. By helping someone, an individual may increase her/his reputation, which may change the pre-disposition of others to help her/him in the future. This, however, depends on what is reckoned as a good or a bad action, i.e., on the adopted social norm responsible for raising or damaging a reputation. In particular, it remains an open question which social norms are able to foster cooperation in small-scale societies, while enduring the wide plethora of stochastic affects inherent to finite populations. Here we address this problem by studying the stochastic dynamics of cooperation under distinct social norms, showing that the leading norms capable of promoting cooperation depend on the community size. However, only a single norm systematically leads to the highest cooperative standards in small communities. That simple norm dictates that only whoever cooperates with good individuals, and defects against bad ones, deserves a good reputation, a pattern that proves robust to errors, mutations and variations in the intensity of selection. PMID:26808261

  6. Small Scale Energy Cascade of the Solar Wind Turbulence

    CERN Document Server

    Alexandrova, O; Veltri, P; Sorriso-Valvo, L

    2007-01-01

    Magnetic fluctuations in the solar wind are distributed according to Kolmogorov's power law $f^{-5/3}$ below the ion cyclotron frequency $f_{ci}$. Above this frequency, the observed steeper power law is usually interpreted in two different ways: a dissipative range of the solar wind turbulence or another turbulent cascade, the nature of which is still an open question. Using the Cluster magnetic data we show that after the spectral break the intermittency increases toward higher frequencies, indicating the presence of non-linear interactions inherent to a new inertial range and not to the dissipative range. At the same time the level of compressible fluctuations raises. We show that the energy transfer rate and intermittency are sensitive to the level of compressibility of the magnetic fluctuations within the small scale inertial range. We conjecture that the time needed to establish this inertial range is shorter than the eddy-turnover time, and is related to dispersive effects. A simple phenomenological mod...

  7. Latent hardening size effect in small-scale plasticity

    International Nuclear Information System (INIS)

    We aim at understanding the multislip behaviour of metals subject to irreversible deformations at small-scales. By focusing on the simple shear of a constrained single-crystal strip, we show that discrete Dislocation Dynamics (DD) simulations predict a strong latent hardening size effect, with smaller being stronger in the range [1.5 µm, 6 µm] for the strip height. We attempt to represent the DD pseudo-experimental results by developing a flow theory of Strain Gradient Crystal Plasticity (SGCP), involving both energetic and dissipative higher-order terms and, as a main novelty, a strain gradient extension of the conventional latent hardening. In order to discuss the capability of the SGCP theory proposed, we implement it into a Finite Element (FE) code and set its material parameters on the basis of the DD results. The SGCP FE code is specifically developed for the boundary value problem under study so that we can implement a fully implicit (Backward Euler) consistent algorithm. Special emphasis is placed on the discussion of the role of the material length scales involved in the SGCP model, from both the mechanical and numerical points of view. (paper)

  8. Numerical simulation of a small-scale biomass boiler

    International Nuclear Information System (INIS)

    Highlights: ► Simplified model for biomass combustion was developed. ► Porous zone conditions are used in the bed. ► Model is fully integrated in a commercial CFD code to simulate a small scale pellet boiler. ► Pollutant emissions are well predicted. ► Simulation provides extensive information about the behaviour of the boiler. - Abstract: This paper presents a computational fluid dynamic simulation of a domestic pellet boiler. Combustion of the solid fuel in the burner is an important issue when discussing the simulation of this type of system. A simplified method based on a thermal balance was developed in this work to introduce the effects provoked by pellet combustion in the boiler simulation. The model predictions were compared with the experimental measurements, and a good agreement was found. The results of the boiler analysis show that the position of the water tubes, the distribution of the air inlets and the air infiltrations are the key factors leading to the high emission levels present in this type of system.

  9. Small-scale anomaly detection in panoramic imaging using neural models of low-level vision

    Science.gov (United States)

    Casey, Matthew C.; Hickman, Duncan L.; Pavlou, Athanasios; Sadler, James R. E.

    2011-06-01

    Our understanding of sensory processing in animals has reached the stage where we can exploit neurobiological principles in commercial systems. In human vision, one brain structure that offers insight into how we might detect anomalies in real-time imaging is the superior colliculus (SC). The SC is a small structure that rapidly orients our eyes to a movement, sound or touch that it detects, even when the stimulus may be on a small-scale; think of a camouflaged movement or the rustle of leaves. This automatic orientation allows us to prioritize the use of our eyes to raise awareness of a potential threat, such as a predator approaching stealthily. In this paper we describe the application of a neural network model of the SC to the detection of anomalies in panoramic imaging. The neural approach consists of a mosaic of topographic maps that are each trained using competitive Hebbian learning to rapidly detect image features of a pre-defined shape and scale. What makes this approach interesting is the ability of the competition between neurons to automatically filter noise, yet with the capability of generalizing the desired shape and scale. We will present the results of this technique applied to the real-time detection of obscured targets in visible-band panoramic CCTV images. Using background subtraction to highlight potential movement, the technique is able to correctly identify targets which span as little as 3 pixels wide while filtering small-scale noise.

  10. Efficient Term Extraction and Indexing Approach in Small-Scale Web Search of Uyghur Language

    Directory of Open Access Journals (Sweden)

    Turdi Tohti

    2013-10-01

    Full Text Available In order to avoid the frequently read-write of hard disk and to speed up the search, the index should be saving in the memory in the small-scale web search. But, to express the original information by fewer memory spaces, also needs for index compression, and this would increases the computation expenses or brings certain harm to the original information in a way. In this research of Uyghur small-scale web search, in order to speed up the retrieval and query speed, inverted index has established uses Hash table data structure and entirely stay resident in memory. In the aspect of index compression, have not uses any compression technique, but proposed a word grouping approach based on simplified N-gram statistical model ,and extracting semantic words that structurally stable, semantically complete and independent ,and greatly reduces the scale of indexing item list. Thereby, not only served the purpose of index compression, but also solved the ambiguity problem certain extent and improved the search precision obviously. The experimental result indicated that, our method is feasible and effective

  11. Small-Scale Spray Releases: Orifice Plugging Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, Lenna A.; Gauglitz, Phillip A.; Blanchard, Jeremy; Kimura, Marcia L.; Kurath, Dean E.

    2012-09-01

    included round holes and rectangular slots. Much of the testing was conducted at pressures of 200 and 380 psi, but some tests were conducted at 100 psi. Testing the largest postulated breaches was deemed impractical because of the large size of some of the WTP equipment. The purpose of the study described in this report is to provide experimental data for the first key technical area, potential plugging of small breaches, by performing small-scale tests with a range of orifice sizes and orientations representative of the WTP conditions. The simulants used were chosen to represent the range of process stream properties in the WTP. Testing conducted after the plugging tests in the small- and large-scale test stands addresses the second key technical area, aerosol generation. The results of the small-scale aerosol generation tests are included in Mahoney et al. 2012. The area of spray generation from large breaches is covered by large-scale testing in Schonewill et al. 2012.

  12. Propulsion engineering study for small-scale Mars missions

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, J.

    1995-09-12

    Rocket propulsion options for small-scale Mars missions are presented and compared, particularly for the terminal landing maneuver and for sample return. Mars landing has a low propulsive {Delta}v requirement on a {approximately}1-minute time scale, but at a high acceleration. High thrust/weight liquid rocket technologies, or advanced pulse-capable solids, developed during the past decade for missile defense, are therefore more appropriate for small Mars landers than are conventional space propulsion technologies. The advanced liquid systems are characterize by compact lightweight thrusters having high chamber pressures and short lifetimes. Blowdown or regulated pressure-fed operation can satisfy the Mars landing requirement, but hardware mass can be reduced by using pumps. Aggressive terminal landing propulsion designs can enable post-landing hop maneuvers for some surface mobility. The Mars sample return mission requires a small high performance launcher having either solid motors or miniature pump-fed engines. Terminal propulsion for 100 kg Mars landers is within the realm of flight-proven thruster designs, but custom tankage is desirable. Landers on a 10 kg scale also are feasible, using technology that has been demonstrated but not previously flown in space. The number of sources and the selection of components are extremely limited on this smallest scale, so some customized hardware is required. A key characteristic of kilogram-scale propulsion is that gas jets are much lighter than liquid thrusters for reaction control. The mass and volume of tanks for inert gas can be eliminated by systems which generate gas as needed from a liquid or a solid, but these have virtually no space flight history. Mars return propulsion is a major engineering challenge; earth launch is the only previously-solved propulsion problem requiring similar or greater performance.

  13. Thermalhydraulic analysis of small-scale tube rupture experiments

    International Nuclear Information System (INIS)

    Guillotine failure of a rupturing pressure tube is an accident situation currently being investigated in the safety analysis of CANDU reactors. One of the reasons for initiating the investigation was to determine the major factors controlling the onset of guillotine failure. As part of this program, small-scale rupture tests using fuel sheaths have been performed and numerically simulated. The fluid dynamic aspects of rupturing fuel sheaths simulated with a multi-dimensional prototype of the two-fluid thermalhydraulic code CATHENA are described in this paper. The results of the numerical simulations were examined by observing the behaviour of pressure transients of the fluid inside the tube during the rupture. A parametric study was first performed to determine optimum model conditions for two-dimensional simulations. Results from CATHENA simulations using these conditions were then compared with experimental data. Calculations were also extended to a three-dimensional thermalhydraulic analysis. This paper describes the results of the parametric and comparative studies. The effect of varying the simulation conditions on calculated pressure transients is also described. Although agreement between simulated results and experimental data was found to be good, some discrepancies were noted and are discussed. Advantages and disadvantages of the three-dimensional study are also presented. This investigation has been successful in demonstrating a method that can be used to enhance the understanding of the behaviour of pressure-tube rupture under accident conditions. Areas in which the numerical analysis could be advanced to further the understanding of rupturing pressure tubes are provided. 3 refs., 11 figs., 2 tabs

  14. Modelling Relativistic Astrophysics at the Large and Small Scale

    Science.gov (United States)

    Haugboelle, Troels

    2005-10-01

    In this thesis different numerical methods, as well as applications of the methods to a number of current problems in relativistic astrophysics, are presented. In the first part the theoretical foundation and numerical implementation of a new general relativistic magnetohydrodynamics code is discussed. A new form of the equations of motion using global coordinates, but evolving the dynamical variables from the point of view of a local observer is presented. No assumptions are made about the background metric and the design is ready to be coupled with methods solving the full Einstein equations. In the second part of the thesis important results concerning the understanding of collisionless shocks, obtained from experiments with a relativistic charged particle code, are presented. Relativistic collisionless shocks are important in a range of astrophysical objects; in particular in gamma ray burst afterglows and other relativistic jets. It is shown that a strong small scale, fluctuating, and predominantly transversal magnetic field is unavoidably generated by a two-stream instability. The magnetic energy density reaches a few percent of equipartition. A new acceleration mechanism for electrons in ion-electron collisionless shocks is proposed. The mechanism is capable of creating a powerlaw electron distribution in a collisionless shocked region. The non-thermal acceleration of the electrons is directly related to the ion current channels generated by the two-stream instability and is local in nature. Thus the observed radiation field may be tied directly to the local conditions of the plasma and could be a strong handle on the physical processes. (abridged)

  15. Collision recognition and direction changes for small scale fish robots by acceleration sensors

    Science.gov (United States)

    Na, Seung Y.; Shin, Daejung; Kim, Jin Y.; Lee, Bae-Ho

    2005-05-01

    Typical obstacles are walls, rocks, water plants and other nearby robots for a group of small scale fish robots and submersibles that have been constructed in our lab. Sonar sensors are not employed to make the robot structure simple enough. All of circuits, sensors and processor cards are contained in a box of 9 x 7 x 4 cm dimension except motors, fins and external covers. Therefore, image processing results are applied to avoid collisions. However, it is useful only when the obstacles are located far enough to give images processing time for detecting them. Otherwise, acceleration sensors are used to detect collision immediately after it happens. Two of 2-axes acceleration sensors are employed to measure the three components of collision angles, collision magnitudes, and the angles of robot propulsion. These data are integrated to calculate the amount of propulsion direction change. The angle of a collision incident upon an obstacle is the fundamental value to obtain a direction change needed to design a following path. But there is a significant amount of noise due to a caudal fin motor. Because caudal fin provides the main propulsion for a fish robot, there is a periodic swinging noise at the head of a robot. This noise provides a random acceleration effect on the measured acceleration data at the collision. We propose an algorithm which shows that the MEMS-type accelerometers are very effective to provide information for direction changes in spite of the intrinsic noise after the small scale fish robots have made obstacle collision.

  16. Financing Sustainable Small-Scale Forestry: Lessons from Developing National Forest Financing Strategies in Latin America

    Directory of Open Access Journals (Sweden)

    Herman Savenije

    2010-12-01

    Full Text Available The problems that hamper the financing of sustainable forest management (SFM are manifold and complex. However, forestry is also facing unprecedented opportunities. The multiple functions and values of forests are increasingly recognized as part of the solution to pressing global issues (e.g., climate change, energy scarcity, poverty, environmental degradation, biodiversity loss and raw material supply. Emerging initiatives to enhance forest carbon stocks and cut greenhouse gas emissions associated with forest clearing (known as REDD+, together with voluntary carbon markets, are offering additional funding options for SFM. Indigenous peoples, local communities and small scale farmers feature as key players in the discourse on implementing such initiatives. Based on the experience of countries developing national forest financing strategies and instruments, we suggest the following points be considered when financing such initiatives, particularly for small scale forestry: (1 Integrate financing of REDD+ and similar initiatives within broader national strategies for SFM financing; (2 Design REDD+ finance mechanisms that are ‘community ready’, i.e., tailored to local realities; (3 Consider existing livelihood strategies as the starting point; (4 Build on existing structures, but be mindful of their strengths and weaknesses; (5 Be strategic with your priority actions; and (6 Promote innovation, knowledge sharing and information exchange.

  17. A greenhouse type solar dryer for small-scale dried food industries: Development and dissemination

    Energy Technology Data Exchange (ETDEWEB)

    Janjai, Serm [Solar Energy Research Laboratory, Department of Physics, Faculty of Science, Silpakorn University, Nakhon Pathom 73000 (Thailand)

    2012-07-01

    In this study, a greenhouse type solar dryer for small-scale dried food industries was developed and disseminated. The dryer consists of a parabolic roof structure covered with polycarbonate sheets on a concrete floor. The system is 8.0m in width, 20.0m in length and 3.5m in height, with a loading capacity about 1,000kg of fruits or vegetables. To ensure continuous drying operation, a 100kW-LPG gas burner was incorporated to supply hot air to the dryer during cloudy or rainy days. Nine 15-W DC fans powered by three 50-W PV modules were used to ventilate the dryer. This dryer was installed for a small-scale food industry at Nakhon Pathom in Thailand to produce osmotically dehydrated tomato. To investigate its performance, the dryer was used to dry 3 batches of osmotically dehydrated tomato. Results obtained from these experiments showed that drying air temperatures in the dryer varied from 35 C to 65 C. In addition, the drying time for these products was 2-3 days shorter than that of the natural sun drying and good quality dried products were obtained. A system of differential equations describing heat and moisture transfers during drying of osmotically dehydrated tomato was also developed. The simulated results agreed well with the experimental data. For dissemination purpose, other two units of this type of dryer were constructed and tested at two locations in Thailand and satisfactory results were obtained.

  18. Small-scale magnetic and velocity inhomogeneities in a sunspot light bridge

    CERN Document Server

    Louis, Rohan E

    2015-01-01

    High resolution spectro-polarimetric observations of a sunspot light bridge by Hinode, reveal small-scale inhomogeneities in the magnetic field and velocity. These inhomogeneities arise as a consequence of a weak, secondary lobe in the Stokes V profile which have a polarity opposite that of the sunspot and very large (>5 km/s) Doppler velocities of both signs, suggesting two distinct types of magnetic anomalies. These two sets of inhomogeneities are highly time-dependent and appear exclusively in the upper half of the light bridge and only after the light bridge is completely formed. Both sets of inhomogeneities appear as patches and can be present independent of the other, next to one another, or spatially separated in a single scan. A two-component inversion of the corresponding spectral profiles indicate that the inhomogeneities occupy a very small fraction, amounting to less than 10 %, of the resolution element. These structures are likely driven by small-scale magneto-convection where they could further ...

  19. Export horticulture – empowering female small-scale farmers in Kenya?

    Directory of Open Access Journals (Sweden)

    Velte, Maria

    2014-09-01

    Full Text Available Export horticulture is one of Kenya’s most dynamic sectors, with the Mount Kenya Region playing a crucial role as a result of its professional large- and small-scale production and marketing structures. The sector is consequently referred to as a “success story of African regional development” (Dolan and Sutherland 2002: 1. A qualitative case study was carried out to understand the impacts on gender inequality of the integration of horticultural smallholdings into the fresh fruit and vegetable (FFV supply chain to the European market. It will be outlined how export horticulture affects female small-scale farmers with reference to local distribution channels, the organisation of the farm as a group or an individual player, and the specific organisation of labour on the farm. The focus here is on the traditional division of labour, ownership and mobility patterns, as well as knowledge and income. The study shows that the influence of the integration in the FFV chain on gender inequality is conditioned by both the type of relations to the buyers and the internal and institutional organisation of the smallholding. Surprisingly, in some areas of the primarily male-dominated rural society, an integration in the form of outgrower schemes that resembles Gereffi et al.’s model of a captive value chain, with women farmers exclusively responsible for export production, can enhance gender equality, as women gradually gain more decision-making power and greater independence.

  20. Small-scale bioenergy projects in rural China: Lessons to be learnt

    International Nuclear Information System (INIS)

    Large amounts of small-scale bioenergy projects were carried out in China's rural areas in light of its national renewable energy policies. These projects applied pyrolysis gasification as the main technology, which turns biomass waste at low costs into biogas. This paper selects seven bioenergy projects in Shandong Province as a case and assesses these projects in terms of economy, technological performance and effectiveness. Results show that these projects have not achieved a satisfying performance after 10 years experience. Many projects have been discontinued. This failure is attributed to a complex of shortcomings in institutional structure, technical level, financial support and social factors. For a more successful future development of bioenergy in rural areas, China should reform its institutional structure, establish a renewable energy market and enhance the technological level of bioenergy projects

  1. Probing dark matter substructure with pulsar timing: II. Improved limits on small-scale cosmology

    CERN Document Server

    Clark, Hamish A; Scott, Pat

    2015-01-01

    Ultracompact Minihalos (UCMHs) have been proposed as a type of dark matter sub-structure seeded by large-amplitude primordial perturbations and topological defects. UCMHs are expected to survive to the present era, allowing constraints to be placed on their cosmic abundance using observations within our own Galaxy. Constraints on their number density can be linked to conditions in the early universe that impact structure formation, such as increased primordial power on small scales, generic weak non-Gaussianity, and the presence of cosmic strings. We use new constraints on the abundance of UCMHs from pulsar timing to place generalised limits on the parameters of each of these cosmological scenarios. At some scales, the limits are the strongest to date, exceeding those from dark matter annihilation. Our new limits have the added advantage of being independent of the particle nature of dark matter, as they are based only on gravitational effects.

  2. Small-scale Geothermal Power Plants Using Hot Spring Water

    Science.gov (United States)

    Tosha, T.; Osato, K.; Kiuchi, T.; Miida, H.; Okumura, T.; Nakashima, H.

    2013-12-01

    The installed capacity of the geothermal power plants has been summed up to be about 515MW in Japan. However, the electricity generated by the geothermal resources only contributes to 0.2% of the whole electricity supply. After the catastrophic earthquake and tsunami devastated the Pacific coast of north-eastern Japan on Friday, March 11, 2011, the Japanese government is encouraging the increase of the renewable energy supply including the geothermal. It needs, however, more than 10 years to construct the geothermal power plant with more than 10MW capacity since the commencement of the development. Adding the problem of the long lead time, high temperature fluid is mainly observed in the national parks and the high quality of the geothermal resources is limited. On the other hand hot springs are often found. The utilisation of the low temperature hot water becomes worthy of notice. The low temperature hot water is traditionally used for bathing and there are many hot springs in Japan. Some of the springs have enough temperature and enthalpy to turn the geothermal turbine but a new technology of the binary power generation makes the lower temp fluid to generate electricity. Large power generators with the binary technology are already installed in many geothermal fields in the world. In the recent days small-scale geothermal binary generators with several tens to hundreds kW capacity are developed, which are originally used by the waste heat energy in an iron factory and so on. The newly developed binary unit is compact suitable for the installation in a Japanese inn but there are the restrictions for the temperature of the hot water and the working fluid. The binary power unit using alternatives for chlorofluorocarbon as the working fluid is relatively free from the restriction. KOBELCO, a company of the Kobe Steel Group, designed and developed the binary power unit with an alternative for chlorofluorocarbon. The unit has a 70 MW class electric generator. Three

  3. Experiments for comparison of small scale rainfall simulators

    Science.gov (United States)

    Iserloh, T.; Ries, J. B.

    2012-04-01

    Small scale portable rainfall simulators are an essential tool in research of recent process dynamics of soil erosion. Such rainfall simulators differ in design, rainfall intensities, rain spectra etc., impeding comparison of the results. Due to different research questions a standardisation of rainfall simulation is not in sight. Nevertheless, the data become progressively important for soil erosion modelling and therefore the basis for decision-makers in application-oriented erosion protection. The project aims at providing a criteria catalogue for estimation of the different simulators as well as the comparability of the results and a uniform calibration procedure for generated rainfall. Within the project "Comparability of simulation results of different rainfall simulators as input data for soil erosion modelling (Deutsche Forschungsgemeinschaft - DFG, Project No. Ri 835/6-1)" many rainfall simulators used by European research groups were compared. The artificially generated rainfall of the rainfall simulators at the Universities Basel, La Rioja, Malaga, Trier, Tübingen, Valencia, Wageningen, Zaragoza and at different Spanish CSIC-institutes (Almeria, Cordoba, Granada, Murcia, Zaragoza) were measured with the same methods (Laser Precipitation Monitor for drop spectra and rain collectors for spatial distribution). The data are very beneficial for improvements of simulators and comparison of simulators and results. Furthermore, they can be used for comparative studies with natural rainfall spectra. A broad range of rainfall data was measured (e.g. intensity: 30 - 149 mmh-1, Christiansen Coefficient for spatial rainfall distribution 61 - 98 %, mean drop diameter 0.375 - 5.0 mm, mean kinetic energy expenditure 25 - 1322 J m-2 h-1, mean kinetic energy per unit area and unit depth of rainfall 4 - 14 J m-2 mm-1). Similarities among the simulators could be found e.g. concerning drop size distributions (maximum drop numbers are reached within the two smallest drop

  4. Experimental investigation of small-scale gasification of woody biomass

    Energy Technology Data Exchange (ETDEWEB)

    Barrio, Maria

    2002-05-01

    A small-scale stratified down draft gasifier has been built and operated under stable conditions using wood pellets as fuel and air as gasification agent. The problems observed during the preliminary experiments have been described and explained; they are mainly related to the stability of the process. The stable operation of the gasifier has been characterised by the gas composition and the product gas tar and particle content. The biomass feeding rate has varied between 4,5 and 6,5 kg/h. The CO content of the product gas (23-26 % vol.) is higher than in similar gasifiers and the H{sub 2} content has been found to vary between 14 and 16 % vol. The tar content in the product gas (Ca. 3 g/Nm{sup 3}) is rather high compared with similar gasifiers. The temperature profile, together with other relevant parameters like the air-excess ratio, the air to fuel ratio and gas to fuel ratio have been calculated. The experiments show that the air excess ratio is rather constant, varying between 0,25 and 0,3. Experiments have been conducted with a gas engine using mixtures of CH{sub 4}, CO, H{sub 2}, CO{sub 2} and N{sub 2} as a fuel. NO{sub x} and CO emissions are analysed. The char gasification process has been studied in detail by means of Thermogravimetric Analysis. The study comprises the chemical kinetics of the gasification reactions of wood char in CO{sub 2} and H{sub 2}O, including the inhibition effect of CO and H{sub 2}. A kinetic model based on Langmuir-Hinshelwood kinetics has been found which relates the mass loss rate to the temperature, gas composition and degree of conversion for each reaction. The ratio CO/CO{sub 2} has been found to be a relevant parameter for reactivity. The gasification experiments in mixtures of CO{sub 2} and H{sub 2}O give reasons to believe that the rate of desorption for the complex C(O) varies depending on the gas mixture surrounding the char. It has been found that if the experimental data are obtained from separate H{sub 2}O/N{sub 2

  5. Small-scale geodiversity and dirt road management, Ede (NL)

    Science.gov (United States)

    van den Ancker, Hanneke; Jungerius, Pieter Dirk

    2016-04-01

    A large part of the countryside roads on the Pleistocene sands of The Netherlands are dirt roads. Most are footpaths, but a small percentage are relatively heavily used by motorized vehicles. These latter roads are a cause subject of debate. Puddles and potholes develop during periods of wet weather, while dust whirls from the roads form during spells of dry weather as do washboard ripples. They cause problems for people living along these roads and tourists (walkers and bikers. The community of Ede (NL), like many other communities on the sand, wants to keep its 80 km of dirt roads because of the natural values they harbour as well as for their characteristic landscape quality and cultural heritage value. A part of the dirt roads in Ede is heavily used. In 2009, the community of Ede developed a decision model to support management of the dirt roads. Ede acknowledges that each dirt road is unique and asks for a tailor-made solution. Road maintenance measures include grading, making a camber, digging pits, applying loam or sandy loam. If problems become too large, one-way traffic can be an option. In more and more cases the dirt roads are barred for motorized through traffic (Gemeente Ede, 2009). As a reconnaissance we have studied the dirt roads of the Horabos/Horalaan over the last year. Incidentally we looked at other parts of the main Horalaan and the footpaths in the adjacent forest of Hoekelum. All dirt roads lie near the top of a Saalian push-moraine in which the upper course of dry valleys are present. Some results of the reconnaissance: - Most dirt roads sections in the Horabos lie lower than the surrounding terrain; - The problems develop in a short period of time during special weather conditions; - Certain dirt road sections e.g. those sections crossing a slight depression are quickly developing potholes; - Even a small slope of the road (Knowledge of geodiversity of the terrain and study of small-scale erosion processes can help to improve the

  6. HOT HORIZONTAL BRANCH STARS IN ω CENTAURI: CLUES ABOUT THEIR ORIGIN FROM THE CLUSTER COLOR MAGNITUDE DIAGRAM

    International Nuclear Information System (INIS)

    We investigate a peculiar feature at the hottest, blue end of the horizontal branch of Galactic globular cluster ω Centauri, using the high-precision and nearly complete catalog that has been constructed from a survey taken with the Advanced Camera for Survey on board the Hubble Space Telescope, that covers the inner 10 x 10 arcmin. It is a densely populated clump of stars with an almost vertical structure in the F435W-(F435W-F625W) plane, that we termed 'blue clump'. A comparison with theoretical models leads to the conclusion that this feature must necessarily harbor either hot flasher stars or canonical He-rich stars-progeny of the blue main sequence (MS) subpopulation observed in this cluster-or a mixture of both types, plus possibly a component from the normal-He population hosted by the cluster. A strong constraint coming from theory is that the mass of the objects in the 'blue clump' has to be very finely tuned, with a spread of at most only ∼0.03 Msun. By comparing observed and theoretical star counts along both the H- and He-burning stages we find that at least 15% of the expected He-rich horizontal branch stars are missing from the color-magnitude diagram. This missing population could be the progeny of red giants that failed to ignite central He-burning and have produced He-core white dwarfs (WDs). Our conclusion supports the scenario recently suggested by Calamida et al. for explaining the observed ratio of WDs to MS stars in ω Centauri.

  7. Mercury Pollution Due to Small-Scale Gold Mining in the Philippines: An Economic Analysis

    OpenAIRE

    Orbeta, Aniceto C.; Israel, Danilo C.; Asirot, Jasminda

    2000-01-01

    The study reviews small-scale gold mining in the Philippines and economically assesses mercury pollution and other development problems in the industry. The end purpose is to suggest measures to address the problems and promote better environmental and overall management of small-scale mining. The study has used secondary data from mining institutions and primary data from key informants and small-scale gold miners and processors in the two case study sites. brazzer

  8. Mercury Pollution Due to Small-Scale Gold Mining in the Philippines: An Economic Analysis

    OpenAIRE

    Israel, Danilo C.; Asirot, Jasminda

    2002-01-01

    The study reviews small-scale gold mining in the Philippines and assesses economically mercury pollution and other development problems of the industry. The end purpose is to suggest measures to address the problems and promote better environmental and overall management of small-scale mining. The study uses secondary data from mining institutions as well as primary data from key informants and small-scale gold miners and processors in the two case study sites.

  9. Small-scale fisheries development in Nigeria: Status, prospects, constraints/recommended solutions

    OpenAIRE

    Aderounmu, A.A.

    1986-01-01

    The small-scale fisheries sector has been contributing immensely towards domestic fish production in Nigeria. Despite considerable contributions by the small-scale fisherman of Nigeria, with few exceptions, they continue to live at the margin of subsistence. This paper attempts to review the sector and propose strategies of integrated approach towards small-scale fisheries development in order to ensure that efforts at improving the rural fisheries succeed in over-coming identified constraint...

  10. Small-scale fisheries resources management options - an overview: a key note address

    OpenAIRE

    Olatunde, A.A.

    1999-01-01

    Small-scale fisheries is traditional and rural based. Therefore, the paper is an over view of small-scale fisheries resources management in Nigeria. It provides about 80-90% employment to surrounding population. The small-scale fisheries are grouped in to two major sectors:- the artisanal or capture fisheries and aquaculture farming. The paper identified some management problems such as:- multi uses of the water bodies, lack of or inadequate data upon which sound management strategies are bas...

  11. Illegal, Unreported And Unregulated Fishing In Small-Scale Marine And Inland Capture Fisheries

    OpenAIRE

    Drammeh, O.K.L.

    2000-01-01

    This paper describes the nature and significance of IUU small-scale fisheries and its evolution, from subsistence activities into activities that are capable of generating significant economic exchanges. The majority of small-scale fisheries are located in the poorer, underdeveloped and developing countries. In most small scale fisheries, access to the fish resources is open, unrestricted and in most cases, unregulated. Fishing activities are hardly reported. The local fisheries administratio...

  12. RELATIONSHIP BETWEEN PERSONALITY AND MOTIVATION FACTORS OF SMALL SCALE WOMEN ENTREPRENEURS

    OpenAIRE

    A.Kaviyarasan; N. Mallika

    2015-01-01

    The present study made an attempt to find out the personality and motivation factors of small scale womenentre preneurs i n Nagapattinam district. The study tried to know whether there any influence of demographic variables on personality and motivation factors of small scale women entrepreneurs. In the present investigation a sample of 100 small scale women entrepreneurs were selected randomly. Primary data were collected from the respondents using questionnaire developed by r...

  13. Technical efficiency and small-scale fishing households in Tanzanian coastal villages: An empirical analysis

    OpenAIRE

    Sesabo, J.K.; Tol, R.S.J.

    2007-01-01

    The effort to conserve fisheries resources and improve the welfare of small-scale fishing households is an important objective of Poverty Reduction Strategies (PRS) in Tanzania. The success of such strategies depends both on the variation and the level of efficiency within small-scale fishing households. This paper examines the technical efficiency of small-scale fishing households in Tanzania using data from two coastal villages (Mlingotini and Nyamanzi). A stochastic frontier (with technica...

  14. Manganese Abundances in the Globular Cluster Omega Centauri

    CERN Document Server

    Cunha, Katia; Bergemann, Maria; Suntzeff, Nicholas B; Lambert, David L

    2010-01-01

    We present manganese abundances in 10 red-giant members of the globular cluster Omega Centauri; 8 stars are from the most metal-poor population (RGB MP and RGB MInt1) while two targets are members of the more metal rich groups (RGB MInt2 and MInt3). This is the first time Mn abundances have been studied in this peculiar stellar system. The LTE values of [Mn/Fe] in Omega Cen overlap those of Milky Way stars in the metal poor Omega Cen populations ([Fe/H] ~ -1.5 to -1.8), however unlike what is observed in Milky Way halo and disk stars, [Mn/Fe] declines in the two more metal-rich RGB MInt2 and MInt3 targets. Non-LTE calculations were carried out in order to derive corrections to the LTE Mn abundances. The non-LTE results for Omega Cen in comparison with the non-LTE [Mn/Fe] versus [Fe/H] trend obtained for the Milky Way confirm and strengthen the conclusion that the manganese behavior in Omega Cen is distinct. These results suggest that low-metallicity supernovae (with metallicities < -2) of either Type II or...

  15. Weed control practices on Costa Rican coffee farms: is herbicide use necessary for small-scale producers?

    OpenAIRE

    Bellamy, Angelina Sanderson

    2010-01-01

    Abstract This paper presents research conducted during two coffee farming seasons in Costa Rica. The study examined coffee farmers? weed management practices and is presented in the form of a case study of small-scale farmers? use of labor and herbicides in weed management practices. Over 200 structured interviews were conducted with coffee farmers concerning their use of hired labor and family labor, weed management activities, support services, and expectations about the future o...

  16. Confronting the Coffee Crisis: Can Fair Trade, Organic, and Specialty Coffees Reduce Small-Scale Farmer Vulnerability in Northern Nicaragua?

    OpenAIRE

    Bacon, Chris

    2004-01-01

    This paper links changing global coffee markets to opportunities and vulnerabilities for sustaining small-scale farmer livelihoods in northern Nicaragua. Changing governance structures, corporate concentration, oversupply, interchangeable commodity grade beans, and low farm gate prices characterize the crisis in conventional coffee markets. In contrast, certified Fair Trade and organic are two alternative forms of specialty coffee trade and production that may offer opportunities for small-sc...

  17. Small scale farmers’ access to and participation in markets : The case of the P4P program in western Kenya

    OpenAIRE

    Skjöldevald, Maja

    2012-01-01

    The purpose of this thesis is to understand how small scale farmers navigate the market to access and participate in the formal maize market to improve their revenue, utilising the case of the P4P program inKenya. The empirical material was collected during fieldwork in Kenya. Qualitative methods were found to be the most suitable for this thesis. The methods that was utilised were a case study strategy, semi structured interviews, focus groups, observations and analysis of secondary sources....

  18. Small-scale expression of proteins in E. coli.

    Science.gov (United States)

    Zerbs, Sarah; Giuliani, Sarah; Collart, Frank

    2014-01-01

    . Despite these advantages, many targets are unsuitable for expression in E. coli, and attempts will not yield protein that can be utilized in downstream applications. A thorough understanding of the protein target, the requirements of the final application, and available tools are all essential for planning a successful expression experiment. This protocol is designed to optimize expression and solubility using an E. coli host and expression vector with an IPTG-inducible T7 promoter. The general features of the method are easily extended to other organisms and expression systems. Small-scale expression cultures are used to identify the optimum expression parameters for a given target. Thorough analysis of the total cell content and soluble fraction is used to screen out failed targets and those unlikely to succeed in large-scale purification cultures. The protocol listed here can be used in individual tubes for a small number of targets or adapted for use in 48-well plates for high throughput applications (Abdullah et al., 2009). Using the same culture for initial expression analysis and solubility analysis reduces variability between expression trials and saves the time required to produce separate cultures. PMID:24423272

  19. Small-Scale Spray Releases: Initial Aerosol Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, Lenna A.; Gauglitz, Phillip A.; Kimura, Marcia L.; Brown, Garrett N.; Kurath, Dean E.; Buchmiller, William C.; Smith, Dennese M.; Blanchard, Jeremy; Song, Chen; Daniel, Richard C.; Wells, Beric E.; Tran, Diana N.; Burns, Carolyn A.

    2013-05-29

    rectangular slots. For the combination of both test stands, the round holes ranged in size from 0.2 to 4.46 mm. The slots ranged from (width × length) 0.3 × 5 to 2.74 × 76.2 mm. Most slots were oriented longitudinally along the pipe, but some were oriented circumferentially. In addition, a limited number of multi-hole test pieces were tested in an attempt to assess the impact of a more complex breach. Much of the testing was conducted at pressures of 200 and 380 psi, but some tests were conducted at 100 psi. Testing the largest postulated breaches was deemed impractical because of the much larger flow rates and equipment that would be required. This report presents the experimental results and analyses for the aerosol measurements obtained in the small-scale test stand. It includes a description of the simulants used and their properties, equipment and operations, data analysis methodologies, and test results. The results of tests investigating the role of slurry particles in plugging small breaches are reported in Mahoney et al. (2012). The results of the aerosol measurements in the large-scale test stand are reported in Schonewill et al. (2012) along with an analysis of the combined results from both test scales.

  20. Small-Scale Spray Releases: Initial Aerosol Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, Lenna A.; Gauglitz, Phillip A.; Kimura, Marcia L.; Brown, Garrett N.; Kurath, Dean E.; Buchmiller, William C.; Smith, Dennese M.; Blanchard, Jeremy; Song, Chen; Daniel, Richard C.; Wells, Beric E.; Tran, Diana N.; Burns, Carolyn A.

    2012-11-01

    rectangular slots. The round holes ranged in size from 0.2 to 4.46 mm. The slots ranged from (width × length) 0.3 × 5 to 2.74 × 76.2 mm. Most slots were oriented longitudinally along the pipe, but some were oriented circumferentially. In addition, a limited number of multi-hole test pieces were tested in an attempt to assess the impact of a more complex breach. Much of the testing was conducted at pressures of 200 and 380 psi, but some tests were conducted at 100 psi. Testing the largest postulated breaches was deemed impractical because of the large size of some of the WTP equipment. This report presents the experimental results and analyses for the aerosol measurements obtained in the small-scale test stand. It includes a description of the simulants used and their properties, equipment and operations, data analysis methodologies, and test results. The results of tests investigating the role of slurry particles in plugging small breaches are reported in Mahoney et al. (2012). The results of the aerosol measurements in the large-scale test stand are reported in Schonewill et al. (2012) along with an analysis of the combined results from both test scales.

  1. Recent progresses in the simulation of small-scale magnetic fields

    CERN Document Server

    Steiner, Oskar

    2007-01-01

    New high-resolution observations reveal that small-scale magnetic flux concentrations have a delicate substructure on a spatial scale of 0.1''. Its basic structure can be interpreted in terms of a magnetic flux sheet or tube that vertically extends through the ambient weak-field or field-free atmosphere with which it is in mechanical equilibrium. A more refined interpretation comes from new three-dimensional magnetohydrodynamic simulations that are capable of reproducing the corrugated shape of magnetic flux concentrations and their signature in the visible continuum. Furthermore it is shown that the characteristic asymmetric shape of the contrast profile of facular granules is an effect of radiative transfer across the rarefied atmosphere of the magnetic flux concentration. I also discuss three-dimensional radiation magnetohydrodynamic simulations of the integral layers from the top of the convection zone to the mid-chromosphere. They show a highly dynamic chromospheric magnetic field, marked by rapidly movi...

  2. Small-Scale Testing of Laterally Loaded Bucket Foundations in Dense Sand

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Foglia, Aligi

    Monopod bucket foundations promise to become a reliable and cost-effective concept for offshore wind turbine. Physical models are essential to understand the behavior of soil-structure systems. When conducting small-scale experiments on soil, scale effects can considerably affect the tests outcome....... In a bid for overcoming this issue, a novel testing system based on the application of suction between the soil surface and a membrane is employed. The comparison between the tests conducted at stress levels of 0 kPa, and the tests with increased stress level, shows remarkable differences. In...... particular, the moment rotation curve of tests with pressure applied show more similar trend to large-scale tests. Further cyclic loading studies may be carried out adopting this testing system to investigate the accumulated rotation of bucket and monopile foundations....

  3. On the validity of the quasi-steady-turbulence hypothesis in representing the effects of large scales on small scales in boundary layers

    Science.gov (United States)

    Agostini, Lionel; Leschziner, Michael

    2016-04-01

    The "quasi-steady hypothesis," as understood in the context of large-scale/small-scale interactions in near-wall turbulence, rests on the assumption that the small scales near the wall react within very short time scales to changes imposed on them by energetic large scales whose length scales differ by at least one order of magnitude and whose energy reaches a maximum in the middle to the outer portion of the log-law layer. A key statistical manifestation of this assumption is that scaling the small-scale motions with the large-scale wall-friction-velocity footprints renders the small-scale statistics universal. This hypothesis is examined here by reference to direct numerical simulation (DNS) data for channel flow at Reτ ≈ 4200, subjected to a large-scale/small-scale separation by the empirical mode decomposition method. Flow properties examined include the mean velocity, second moments, joint probability density functions, and skewness. It is shown that the validity of the hypothesis depends on the particular property being considered and on the range of length scales of structures included within the large-scale spectrum. The quasi-steady hypothesis is found to be well justified for the mean velocity and streamwise energy of the small scales up to y + ˜ O ( 80 ) , but only up to y + ˜ O ( 30 ) for other properties.

  4. Dinamica numerica di microsonde verso Alfa Centauri con impulsi LASER su vele spaziali

    Science.gov (United States)

    Sigismondi, Costantino

    2016-05-01

    Starshot project aims to reach alpha Centauri at 4.4 light years in 24 years, by accelerating to velocity 0.2 c with collimated LASER light pressure for 1000s several grams-scale microprobes with space sails. The energetics and dynamical equations are solved numerically on a worksheet and discussed.

  5. Modeling Of Small Scale Surface Deformation Based On DInSAR Result

    Science.gov (United States)

    Furuta, Ryoichi

    2012-01-01

    Monitoring of small scale surface deformation as subsidence and landslides is very important to protect lifeline, manmade structures, buildings and houses, roads and railways, and so on. In order to monitor subsidence and landslides, several technologies were applied. However, these technologies cannot be applied to broad area and it is difficult to understand spatial distribution of affected area of subsidence and landslides. DInSAR analysis can be understand spatial distribution of affected area of subsidence and landslide, therefore, it has high prospect in Japan because Japan has a lot of sites of subsidence and landslides. However, DInSAR analysis cannot extract sub-surface information like depth of source of deformation. In order to enhance a capability of detection of small scale surface deformation as subsidence and landslide by DInSAR analysis, integration use of DInSAR analysis and numerical model and original model for estimation of small scale surface deformation was proposed in this paper. Proposed model was applied to subsidence which was detected by ALOS PALSAR DInSAR. Target area is located in the North-East part of China. At the target area, large subsidence occurred due to coal mining activity and overuse of ground water. In order to consider way of countermeasure work for subsidence, it is important to know affected area of subsidence, depth of source of subsidence, and so on. Affected area of subsidence can be understood by the DInSAR analysis, however, depth of source of subsidence has difficult to understand by the DInSAR analysis. In order to understand the depth of source of subsidence, numerical model was necessary. Proposed model can be estimating affected area of subsidence and depth of source of subsidence by a few parameters derived from DInSAR analysis. Proposed model was well performed in the simulation of subsidence pattern of 1-D space and it could be estimated depth of subsidence source. However, it wasn't well performed to

  6. CFD Modelling of Biomass Combustion in Small-Scale Boilers. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Xue-Song Bai; Griselin, Niklas; Klason, Torbern; Nilsson, Johan [Lund Inst. of Tech. (Sweden). Dept. of Heat and Power Engineering

    2002-10-01

    This project deals with CFD modeling of combustion of wood in fixed bed boilers. A flamelet model for the interaction between turbulence and chemical reactions is developed and applied to study small-scale boiler. The flamelet chemistry employs 43 reactive species and 174 elementary reactions. It gives detailed distributions of important species such as CO and NO{sub x} in the flow field and flue gas. Simulation of a small-scale wood fired boiler measured at SP Boraas (50 KW) shows that the current flamelet model yields results agreeable to the available experimental data. A detailed chemical kinetic model is developed to study the bed combustion process. This model gives boundary conditions for the CFD analysis of gas phase volatile oxidation in the combustion chambers. The model combines a Functional Group submodel with a Depolymerisation, Vaporisation and Crosslinking submodel. The FG submodel simulates how functional groups decompose and form light gas species. The DVC submodell predicts depolymerisation and vaporisation of the macromolecular network and this includes bridge breaking and crosslinking processes, where the wood structure breaks down to fragments. The light fragments form tar and the heavy ones form metaplast. Two boilers firing wood log/chips are studied using the FG-DVC model, one is the SP Boraas small-scale boiler (50 KW) and the other is the Sydkraft Malmoe Vaerme AB's Flintraennan large-scale boiler (55 MW). The fix bed is assumed to be two zones, a partial equilibrium drying/devolatilisation zone and an equilibrium zone. Three typical biomass conversion modes are simulated, a lean fuel combustion mode, a near-stoichiometric combustion and a fuel rich gasification mode. Detailed chemical species and temperatures at different modes are obtained. Physical interpretation is provided. Comparison of the computational results with experimental data shows that the model can reasonably simulate the fixed bed biomass conversion process. CFD

  7. Women's occupational health working in small-scale agriculture in South Africa

    NARCIS (Netherlands)

    Naidoo, S.

    2011-01-01

    In developing economies women’s contributions are in agriculture. Trends indicate that women’s participation in small-scale agriculture is increasing. On the Makhatini Flats in northern KwaZulu-Natal intensive small-scale farming takes place with > 4 000 women involved. A cross-sectional study on th

  8. Wine Grape Production: A Promising Enterprise for Small Scale Enterprises in North Carolina?

    OpenAIRE

    Jefferson-Moore, Kenrett Y.; Bynum, Jarvetta S.; Mosley, Jannety M.

    2008-01-01

    We investigate wine grape production as a promising enterprise for small scale enterprises in North Carolina. Although results indicate that wine grape production is an ideal alternative enterprise for small scale producers, growers will have to wait at least 15 years to receive a complete return on the initial investment.

  9. Economic importance of the dutch non-commercial small-scale fleet

    OpenAIRE

    BARTELINGS H.; Oostenbrugge, van, H.

    2007-01-01

    This paper describes the characteristics, costs and revenues of the so-called noncommercial small-scale fleet based on a survey sent to all the skippers owning a vessel that according to the LEI definition falls within the category of non-commercial small-scale fisheries. With this data the economic importance of this part of the fleet can be determined.

  10. Workshop on Small-Scale Fisheries. Kavala, Greece 12th -16th September 2005

    OpenAIRE

    2005-01-01

    The workshop on Small-Scale Fisheries took place in Kavala, Greece, from the 12th until the 16th of September 2005. Representatives of 12 countries attended the meeting. Priory to the workshop a discussion was held on “Fleet based approach for the Mediterranean Small Scale Fisheries according to the conclusions of the last Mediterranean coordination meeting in Athens”.

  11. Methodological foundations of evaluation of effectiveness indicators of small-scale business activities

    Directory of Open Access Journals (Sweden)

    Ivanova T.

    2013-01-01

    Full Text Available The methodological approach to the measurement of financial indicators of small-scale enterprises has been developed. It enables to secure the comparability of financial condition indicators and the results of small-scale enterprise activities, and also to develop the methods of vertical integral estimate calculation at separate aspects of financial condition and the results of smallscale enterprise activities.

  12. FarmLime manual: for small-scale production of agricultural lime

    OpenAIRE

    Mitchell, C. J.; Mwanza, M.

    2005-01-01

    This manual is a concise guide to the small-scale production of agricultural lime. It was developed as part of a research project, ‘Low-cost lime for small-scale farming’ otherwise known as FarmLime (Mitchell, CJ, 2005). The ideal agricultural lime is a ground dolomite or dolomitic limestone with a particle size of 100%

  13. Category, narrative and value in the governance of small-scale fisheries

    NARCIS (Netherlands)

    Johnson, D.S.

    2006-01-01

    Since the 1970s, small-scale fisheries have had an important place in fisheries social science and in fisheries management. While there has been substantial discussion of what constitutes the category of small-scale fisheries, its considerable ambiguity is nevertheless often passed over. This paper

  14. Medium/small-scale computers HITACHI M-620, M-630, and M-640 systems: the aim of development and characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, N.; Saiki, Y.; Sunaga, K. (Hitachi, Ltd., Tokyo (Japan))

    1990-10-01

    The medium/small-scale HITACHI M-620, M-630, and M-640 computer systems are outlined. Every system is featured by the configuration usable as a medium or small-scale host computer in offices, the function connectable with large-scale host computers, the performance of 5-50 times those of conventional office computers, easy operation and fast processing. As features of the hardware, the one-board CPU and small integrated cubicle structure containing the CPU board, high-speed large-capacity magnetic disk storage device, various kinds of controllers and others are illustrated. As features of the software, the OS (VOS K) featured by the virtual data space control (VDSA) and relational database (RDB) functions, EAGLE/4GL (effective approach to achieving high level software productivity/4th generation language), STEP (self training environmental support program) and simple end user language ACE3/E2 are outlined. 7 figs.

  15. Spatial distribution and statistical properties of small-scale convective vortex-like motions in a quiet-Sun region

    Science.gov (United States)

    Vargas Domínguez, S.; Palacios, J.; Balmaceda, L.; Cabello, I.; Domingo, V.

    2011-09-01

    High-resolution observations of a quiet-Sun internetwork region taken with the Solar 1-m Swedish Telescope in La Palma are analysed. We determine the location of small-scale vortex motions in the solar photospheric region by computing the horizontal proper motions of small-scale structures on time-series of images. These plasma convectively driven swirl motions are associated to (1) downdrafts (that have been commonly explained as corresponding to sites where the plasma is cooled down and hence returned to the interior below the visible photospheric level) and (2) horizontal velocity vectors converging on a central point. The sink cores are proved to be the final destination of passive floats tracing plasma flows towards the centre of each vortex. We establish the occurrence of these events to be 1.4 × 10-3 and 1.6 × 10-3 vortices Mm-2 min-1, respectively, for the two time-series analysed here.

  16. Dielectric function of a plasma with strong small-scale density variations

    International Nuclear Information System (INIS)

    Questions of wave propagation and investigations of superthermal particles in a plasma with strong small-scale irregularities have recently acquired urgency in connection with experiments on the interaction of high-power radio signals with the ionospheric plasma. In these experiments strong density variations which are small in scale compared with the wavelength of the incident electromagnetic wave are observed, resulting from the excitation of thermal and ponderomotive parametric instabilities close to the pump wave reflection point. The theoretical study of the problem of electromagnetic wave propagation in such a medium encounters a number of fundamental difficulties. These are related to finding the effective field under resonant conditions in a complex medium such as a plasma with small-scale irregularities imbedded in it. An important advance was made where renormalization of the field was used to approach the plasma resonance quite closely. However, the iteration technique used to find the effective dielectric function is inapplicable in the immediate vicinity of the resonance. On the other hand, experimental and theoretical studies reveal that when the pump wave power is high enough the irregularities acquire the form of cavitons: localized structures separated fairly far from one another. The Born approximation is no longer suitable for describing such a medium; but on the other hand for analytical calculations one can use the small parameter n that characterizes the packing density of these irregularities in space. In the present work the authors study the resonant properties of such a medium in the approximation n much-lt 1. In particular, they find the effective dielectric function var-epsilon eff by taking into account the geometrical resonances of the individual irregularities. 3 refs

  17. Small-scale health-related indicator acquisition using secondary data spatial interpolation

    Directory of Open Access Journals (Sweden)

    Thompson Mary E

    2010-10-01

    Full Text Available Abstract Background Due to the lack of small-scale neighbourhood-level health related indicators, the analysis of social and spatial determinants of health often encounter difficulties in assessing the interrelations of neighbourhood and health. Although secondary data sources are now becoming increasingly available, they usually cannot be directly utilized for analysis in other than the designed study due to sampling issues. This paper aims to develop data handling and spatial interpolation procedures to obtain small area level variables using the Canadian Community Health Surveys (CCHS data so that meaningful small-scale neighbourhood level health-related indicators can be obtained for community health research and health geographical analysis. Results Through the analysis of spatial autocorrelation, cross validation comparison, and modeled effect comparison with census data, kriging is identified as the most appropriate spatial interpolation method for obtaining predicted values of CCHS variables at unknown locations. Based on the spatial structures of CCHS data, kriging parameters are suggested and potential small-area-level health-related indicators are derived. An empirical study is conducted to demonstrate the effective use of derived neighbourhood variables in spatial statistical modeling. Suggestions are also given on the accuracy, reliability and usage of the obtained small area level indicators, as well as further improvements of the interpolation procedures. Conclusions CCHS variables are moderately spatially autocorrelated, making kriging a valid method for predicting values at unsampled locations. The derived variables are reliable but somewhat smoother, with smaller variations than the real values. As potential neighbourhood exposures in spatial statistical modeling, these variables are more suitable to be used for exploring potential associations than for testing the significance of these associations, especially for associations

  18. A greenhouse type solar dryer for small-scale dried food industries: Development and dissemination

    Directory of Open Access Journals (Sweden)

    Serm Janjai

    2012-01-01

    Full Text Available In this study, a greenhouse type solar dryer for small-scale dried food industries was developed and disseminated. The dryer consists of a parabolic roof structure covered with polycarbonate sheets on a concrete floor. The system is 8.0m in width, 20.0m in length and 3.5m in height, with a loading capacity about 1,000kg of fruits or vegetables. To ensure continuous drying operation, a 100kW-LPG gas burner was incorporated to supply hot air to the dryer during cloudy or rainy days. Nine 15-W DC fans powered by three 50-W PV modules were used to ventilate the dryer. This dryer was installed for a small-scale food industry at Nakhon Pathom in Thailand to produce osmotically dehydrated tomato. To investigate its performance, the dryer was used to dry 3 batches of osmotically dehydrated tomato. Results obtained from these experiments showed that drying air temperatures in the dryer varied from 35°C to 65°C. In addition, the drying time for these products was 2-3 days shorter than that of the natural sun drying and good quality dried products were obtained. A system of differential equations describing heat and moisture transfers during drying of osmotically dehydrated tomato was also developed. The simulated results agreed well with the experimental data. For dissemination purpose, other two units of this type of dryer were constructed and tested at two locations in Thailand and satisfactory results were obtained.

  19. An assessment of health practises among small-scale farmers in Kwara State, Nigeria

    Directory of Open Access Journals (Sweden)

    Jones A. Akangbe

    2015-09-01

    Full Text Available Objective. The study examines the personal health practices of small scale farmers in Kwara State, Nigeria. Materials and Methods. Primary data were obtained using a well-structured questionnaire which was distributed to 120 small scale farmers. Descriptive statistical techniques such as frequency count, percentages were used, as well as Pearson Product Moment correlation and analysis for empirical analysis. Results. Results revealed that more than half (55% smoke cigarettes, about 48% drink alcohol to a very great extent, while the majority (64.5% indicated they have not been screened to know their HIV status. On a positive note, the results further show that the majority 70%, 53.3%, 80% and 73.3% indicated that they eat a balance diet, engage in physical activity, practice safer sex, and regularly visit a health care centre, respectively. It also revealed that 77% have not attended any training on healthy living. The results of PPMC showed that the health knowledge of respondents had significant (p<0.01 influence on practices like cigarette smoking, eating a balance diet and regular visits to a health care centre. Conclusion. It was concluded that health threatening practices such as cigarette smoking and drinking alcohol among the majority of the respondents, coupled with their lack of health knowledge from health professionals, contributes to the poor health status of respondents which eventually negatively influences the labour efficiency of farmers. It is recommended that farmers should endeavour to make use of health literacy programmes introduced to them at local government level, and that the government should provide more of these health literacy programmes.

  20. The epidemiology and small-scale spatial heterogeneity of urinary schistosomiasis in Lusaka province, Zambia

    Directory of Open Access Journals (Sweden)

    Christopher Simoonga

    2008-11-01

    Full Text Available In line with the aims of the “National Bilharzia Control Programme” and the “School Health and Nutrition Programme” in Zambia, a study on urinary schistosomiasis was conducted in 20 primary schools of Lusaka province to further our understanding of the epidemiology of the infection, and to enhance spatial targeting of control. We investigated risk factors associated with urinary schistosomiasis, and examined small-scale spatial heterogeneity in prevalence, using data collected from 1,912 schoolchildren, 6 to 15-year-old, recruited from 20 schools in Kafue and Luangwa districts. The risk factors identified included geographical location, altitude, normalized difference vegetation index (NDVI, maximum temperature, age, sex of the child and intermediate host snail abundance. Three logistic regression models were fitted assuming different random effects to allow for spatial structuring. The mean prevalence rate was 9.6%, with significance difference between young and older children (odds ratio (OR = 0.71; 95% confidence interval (CI = 0.51-0.96. The risk of infection was related to intermediate host snail abundance (OR = 1.03; 95% CI = 1.00-1.05 and vegetation cover (OR = 1.04; 95% CI = 1.00-1.07. Schools located either on the plateau and the valley also differed in prevalence and intensity of infection for moderate infection to none (OR = 1.64; 95% CI = 1.36- 1.96. The overall predictive performance of the spatial random effects model was higher than the ordinary logistic regression. In addition, evidence of heterogeneity of the infection risk was found at the micro-geographical level. A sound understanding of small-scale heterogeneity, caused by spatial aggregation of schoolchildren, is important to inform health planners for implementing control schistosomiasis interventions.

  1. Rainwater harvesting for small-scale irrigation of maize in the Central Rift Valley, Ethiopia

    Science.gov (United States)

    Keesstra, Saskia; Hartog, Maaike; Muluneh, Alemayehu; Stroosnijder, Leo

    2013-04-01

    In the Central Rift Valley of Ethiopia, small scale farmers mostly rely on rainfall for crop production. The erratic nature of rainfall causes frequent crop failures and makes the region structurally dependent on food aid. Rainwater Harvesting (RWH) is a technique to collect and store runoff that could provide water for livestock, domestic use or small scale irrigation. Usually, such irrigation is promoted for high value crops, but in the light of regional food security it may become interesting to invest in irrigation of maize. In this research, two cemented RWH cisterns were investigated to determine their economic and social potential for supplemental irrigation of maize using drip irrigation. For this, data from test fields with irrigated maize and monitoring of water levels of the cisterns were used, as well as a survey under 30 farmers living close to the experimental site. The results show that catchment size and management should be in balance with the designed RWH system, to prevent too little runoff or flooding. An analysis with Cropwat 8.0 was used to investigate the possibility of irrigating maize with the observed amounts of water in the RWH cisterns. This would suffice for 0.3-0.8 ha of maize. For a RWH cistern with a drip irrigation system to be economically viable, the production on this acreage should become 3-4 ton/ha; 2.5 times higher than the current yield. But the biggest challenge would be to change the perception of respondents, who don't find it logical to spend precious water on a common crop like maize. Therefore, if the Ethiopian government considers the irrigation of maize to be important for regional food security, it is recommended to either subsidize the construction of RWH cisterns or provide credit on favourable terms.

  2. Case study of the cause and the dynamic structure for a small-scale snowstorm event associated with a cyclone%一次入海气旋局地暴雪的结构演变及成因观测分析

    Institute of Scientific and Technical Information of China (English)

    杨成芳; 周淑玲; 刘畅; 郭俊建; 杨璐瑛

    2015-01-01

    This study investigates the cause and the dynamic structure on a small-scale snowstorm event occurred in the Shan-dong peninsula with the Doppler radar,profile,automatic station,routine sounding and surface observation data.the results are as follows:(1)Precipitation occurred in the two stages:the first weak precipitation one was typical snowstorm caused by the Huanghe cyclone with the characteristic of weak snowfall and north-east radar echo,and the second strong precipitation one behind the cyclone was ocean-effect snowstorm with the characteristic of strong snowfall and south-west radar echo.(2)Favor-able synoptic situation led to the occurrence of the first stage snow,such as the obvious trough,cyclonic circulation,south-western low-level jet and surface cyclone.Its vapor came from the South China Sea.The snowfall was distributed to ahead of southwestern low-level jet on the right and eastern side of the surface cyclone.(3)By contrast,the second precipitation stage occurred after the trough passed the Shandong peninsula and the cyclone passed through the Bohai straight to the Huanghai Sea.Cold air intruded into the Shandong peninsula from the Bohai straight and the Huanghai Sea.North-east wind was prevail-ing and its speed was stronger than the north-west wind,which brought rich water vapor and heat.Snowfall distributed within north-east wind.And,(4)the structure of wind field in the lower troposphere was different during the ocean-effect snowstorm. At the beginning,there was a mid-γscale low circulation beside the north coastal area in the Shandong peninsula,and radar ra-dial velocity shows a meso-βvortex in low level.Meanwhile,there was a shear between the south-east wind and north-west wind near the east coastal area.During the strong snowfall,a shear between the north-east and north-west wind was found in the boundary layer.Both the low circulation and shear are the favorable dynamic factors.As a result,the case implies that re-markable difference between

  3. Small-scale behavior of Hall magnetohydrodynamic turbulence

    Science.gov (United States)

    Stawarz, Julia E.; Pouquet, Annick

    2015-12-01

    Decaying Hall magnetohydrodynamic (HMHD) turbulence is studied using three-dimensional (3D) direct numerical simulations with grids up to 7683 points and two different types of initial conditions. Results are compared to analogous magnetohydrodynamic (MHD) runs and both Laplacian and Laplacian-squared dissipative operators are examined. At scales below the ion inertial length, the ratio of magnetic to kinetic energy as a function of wave number transitions to a magnetically dominated state. The transition in behavior is associated with the advection term in the momentum equation becoming subdominant to dissipation. Examination of autocorrelation functions reveals that, while current and vorticity structures are similarly sized in MHD, HMHD current structures are narrower and vorticity structures are wider. The electric field autocorrelation function is significantly narrower in HMHD than in MHD and is similar to the HMHD current autocorrelation function at small separations. HMHD current structures are found to be significantly more intense than in MHD and appear to have an enhanced association with strong alignment between the current and magnetic field, which may be important in collisionless plasmas where field-aligned currents can be unstable. When hyperdiffusivity is used, a longer region consistent with a k-7 /3 scaling is present for right-polarized fluctuations when compared to Laplacian dissipation runs.

  4. Responses of seabirds, in particular prions ( Pachyptila sp.), to small-scale processes in the Antarctic Polar Front

    Science.gov (United States)

    van Franeker, Jan A.; van den Brink, Nico W.; Bathmann, Ulrich V.; Pollard, Raymond T.; de Baar, Hein J. W.; Wolff, Wim J.

    Small-scale distribution patterns of seabirds in the Antarctic Polar Front (APF) were investigated in relation to other biological, physical, and chemical features during the ANT-XIII/2 research cruise of R.V. Polarstern from December 1995 to January 1996. The APF is characterized by steep gradients in sea-surface temperature and salinity. Within the APF, gradient zones were closely associated with elevated levels of primary production, chlorophyll- a (chl- a) concentrations, and zooplankton densities. Even broad-billed prions (' Pachyptila vittata-group'), which dominated the seabird community by 83% in carbon requirements, showed small-scale distributional patterns that were positively related to primary production, chl- a, and total zooplankton densities. The findings demonstrate a close, direct link between fine-scale physical processes in the APF and biological activity through several food web levels up to that of zooplankton-eating seabirds. Broad-billed prions appeared to forage on very small copepods ( Oithona spp.) in close association with the front. Fish- and squid-eating predators showed poor correlations with small-scale spatial structures of the APF. However, in a wider band around the APF, most top predators did occur in elevated densities, showing gradual spatio-temporal diffusion of the impact of the APF on higher trophic levels.

  5. Small-scale hydroelectric power in the southeast: new impetus for an old energy source

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    The Southeastern conference, Small-Scale Hydroelectric Power: New Impetus for an Old Energy Source, was convened to provide a forum for state legislators and other interested persons to discuss the problems facing small-scale hydro developers, and to recommend appropriate solutions to resolve those problems. During the two-day meeting state legislators and their staffs, along with dam developers, utility and industry representatives, environmentalists and federal/state officials examined and discussed the problems impeding small-scale hydro development at the state level. Based upon the problem-oriented discussions, alternative policy options were recommended for consideration by the US Department of Energy, state legislatures and the staff of the National Conference of State Legislatures (NCSL). Emphasis was placed on the legal, institutional, environmental and economic barriers at the state level, as well as the federal delays associated with licensing small-scale hydro projects. Whereas other previously held conferences have emphasized the identification and technology of small-scale hydro as an alternative energy source, this conference stressed legislative resolution of the problems and delays in small-scale hydro licensing and development. Panel discussions and workshops are summarized. Papers on the environmental, economic, and legal aspects of small-scale hydropower development are presented. (LCL)

  6. Binary Quasars in the Sloan Digital Sky Survey: Evidence for Excess Clustering on Small Scales

    CERN Document Server

    Hennawi, J F; Oguri, M; Inada, N; Richards, G T; Pindor, B; Schneider, D P; Becker, R H; Gregg, M D; Hall, P B; Johnston, D E; Fan, X; Burles, S; Schlegel, D J; Gunn, J E; Lupton, R; Bahcall, Neta A; Brunner, R J; Brinkmann, J; Hennawi, Joseph F.; Strauss, Michael A.; Oguri, Masamune; Inada, Naohisa; Richards, Gordon T.; Pindor, Bartosz; Schneider, Donald P.; Becker, Robert H.; Gregg, Michael D.; Hall, Patrick B.; Johnston, David E.; Fan, Xiaohui; Burles, Scott; Schlegel, David J.; Gunn, James E.; Lupton, Robert; Bahcall, Neta A.; Brunner, Robert J.; Brinkman, Jon

    2006-01-01

    We present a sample of 218 new quasar pairs with proper transverse separations R_prop 3 Mpc/h quasar correlation function, extrapolated down as a power law to the separations probed by our binaries. The excess grows to ~ 30 at R_prop ~ 10 kpc/h, and provides compelling evidence that the quasar autocorrelation function gets progressively steeper on sub-Mpc scales. This small scale excess can likely be attributed to dissipative interaction events which trigger quasar activity in rich environments. Recent small scale measurements of galaxy clustering and quasar-galaxy clustering are reviewed and discussed in relation to our measurement of small scale quasar clustering.

  7. Evaluation of Small-Scale Laterally Loaded Non-Slender Monopiles in Sand

    DEFF Research Database (Denmark)

    Roesen, Hanne Ravn; Thomassen, Kristina; Sørensen, Søren Peder Hyldal;

    -slender piles in sand is evaluated by means of results from six small-scale laboratory tests, numerical modelling of the same test setup and existing theory. From the numerical models p-y curves are conducted and compared to current design regulations. It is found that the recommendations in API (1993) and DNV...... suggestions in Sørensen et al. (2010). It is found that considerable uncertainties are related to small-scale testing, and the different evaluations clearly indicate that the accuracy of small-scale testing is increased when increasing the pile diameter and applying overburden pressure....

  8. Small-scale upgrading and refinement of biogas; Smaaskalig uppgradering och foeraedling av biogas

    Energy Technology Data Exchange (ETDEWEB)

    Blom, Helena; Mccann, Michael; Westman, Johan (Poeyry SwedPower AB, Stockholm (Sweden))

    2012-02-15

    Small-scale upgrading and refinement of biogas is a report which aims to compile the state of knowledge in small-scale biogas upgrading. The project have been a collaboration with Agrovaest and Energy Farm and was funded by the Foundation for Agricultural Research, Western Goetaland and the Agriculture Department. The technology available for small scale upgrade has been examined from the technical and economic standpoint. An economic comparison has been made and the production of upgraded biogas has been estimated for different raw gas flows. The work also contains information related to biogas production, upgrading and a comparison of liquid biogas, DME and Ecopar-diesel

  9. Modelling biomass-fuelled small-scale CHP plants for process synthesis optimisation

    OpenAIRE

    Savola, Tuula

    2007-01-01

    In this work possible process improvements for biomass-fuelled small-scale combined heat and power (CHP) plants are evaluated and a new mixed integer nonlinear programming (MINLP) model for process synthesis optimisation of these processes is presented. Small-scale (1-20 MWe) CHP plants are of interest, as in Finland the potential to increase the CHP production is in converting small heating units to CHP production. However, the profitability of these small-scale CHP investments should be hig...

  10. Supply Chain Factors Influencing Small Scale Farmers’ Tea Production in Abothuguchi West Division in Kenya

    OpenAIRE

    Paul Mbaabu Karanga; Henry M. Bwisa

    2014-01-01

    Low yields on the small scale tea farmers in Kenya led to this study. The purpose of this study was to establish the supply chain factors influencing small scale tea production in Abothuguchi West Division in Kenya. A survey of 70 small scale tea farmers of AWD was carried out with a target population of 5000 farmers registered to supply tea to the Kenya Tea Development Agency managed by Githongo Tea Factory. A questionnaire and interview guide was used to collect the data. A response rate of...

  11. Direct Numerical Simulations of Small-Scale Gravity Wave Instability Dynamics in Variable Stratification and Shear

    Science.gov (United States)

    Mixa, T.; Fritts, D. C.; Laughman, B.; Wang, L.; Kantha, L. H.

    2015-12-01

    Multiple observations provide compelling evidence that gravity wave dissipation events often occur in multi-scale environments having highly-structured wind and stability profiles extending from the stable boundary layer into the mesosphere and lower thermosphere. Such events tend to be highly localized and thus yield local energy and momentum deposition and efficient secondary gravity wave generation expected to have strong influences at higher altitudes [e.g., Fritts et al., 2013; Baumgarten and Fritts, 2014]. Lidars, radars, and airglow imagers typically cannot achieve the spatial resolution needed to fully quantify these small-scale instability dynamics. Hence, we employ high-resolution modeling to explore these dynamics in representative environments. Specifically, we describe numerical studies of gravity wave packets impinging on a sheet of high stratification and shear and the resulting instabilities and impacts on the gravity wave amplitude and momentum flux for various flow and gravity wave parameters. References: Baumgarten, Gerd, and David C. Fritts (2014). Quantifying Kelvin-Helmholtz instability dynamics observed in noctilucent clouds: 1. Methods and observations. Journal of Geophysical Research: Atmospheres, 119.15, 9324-9337. Fritts, D. C., Wang, L., & Werne, J. A. (2013). Gravity wave-fine structure interactions. Part I: Influences of fine structure form and orientation on flow evolution and instability. Journal of the Atmospheric Sciences, 70(12), 3710-3734.

  12. The far-ultraviolet UPS and downs of Alpha Centauri

    Energy Technology Data Exchange (ETDEWEB)

    Ayres, Thomas R., E-mail: Thomas.Ayres@Colorado.edu [Center for Astrophysics and Space Astronomy, 389 UCB, University of Colorado, Boulder, Co 80309 (United States)

    2015-02-01

    Four years (2010–2014) of semiannual pointings by the Hubble Space Telescope Imaging Spectrograph (STIS) on nearby Alpha Centauri have yielded a detailed time history of far-ultraviolet (FUV: 1150–1700 Å) emissions of the solarlike primary (A: G2 V) and the cooler but more active secondary (B: K1 V). This period saw A climbing out of a prolonged coronal X-ray minimum, as documented contemporaneously by Chandra, while B was rising to, then falling from, a peak of its long-term (∼8 year) starspot cycle. The FUV fluxes of the primary were steady over most of the STIS period, although the [Fe xii] λ1242 coronal forbidden line (T∼1.5 MK) partly mirrored the slowly rising X-ray fluxes. The FUV emissions of the secondary more closely tracked the rise and fall of its coronal luminosities, especially the “hot lines” Si iv, C iv, and N v (T∼0.8–2 × 10{sup 5} K), and coronal [Fe xii] itself. The hot lines of both stars were systematically redshifted, relative to narrow chromospheric emissions, by several km s{sup −1}, showing little change in amplitude over the four-year period, especially for α Cen B, despite the significant evolution of its coronal activity. Further, the hot lines of both stars, individually and epoch-averaged, displayed non-Gaussian shapes, which most trivially could be decomposed into two components, one narrow (FWHM ∼25–45 km s{sup −1}), the other broad (60–80 km s{sup −1}). A bimodal Gaussian strategy had been applied previously to the α Cen stars, but this was the first opportunity to evaluate any time dependence. In fact, not much variation of the component properties was seen, even over the major cycle changes of B. Curiously, the line fluxes were about equally divided between the narrow and broad components for both stars. The fact that there is minimal activity dependence of the narrow/broad flux partition, as well as densities derived from O iv] line ratios, either during the cycle evolution of B or between A and

  13. Experimental observation on a small-scale thermoacoustic prime mover

    Institute of Scientific and Technical Information of China (English)

    JIN Tao; ZHANG Bao-sen; TANG Ke; BAO Rui; CHEN Guo-bang

    2007-01-01

    A miniature thermoacoustic prime mover, consuming heat to radiate sound, may be considered as a potential way of heat management in microcircuits because of its simplicity and stability. A prototype with variable resonant tube length of 10 to 25 cm was built, and experiments were carried out to observe its performance, such as onset temperature, oscillation amplitude and operating frequency. The results with atmospheric air showed that proper structures and operating conditions can make the system start an oscillation at a temperature lower than 100 ℃, which proves the feasibility of potential usage in electronic units. The influences of stack position, heat input power or tube inclination on the oscillation amplitude, onset temperature and operating frequency are also presented.

  14. Growth and Efficiency of Small Scale Industry and its Impact on Economic Development of Sindh

    Directory of Open Access Journals (Sweden)

    Mumtaz Ali Junejo

    2008-09-01

    Full Text Available The purpose of this study is to analyze the growth, efficiency, causes of sickness of small scale industry, emergence of entrepreneur and competencies of entrepreneurs at Larkana estate area of Sindh Province. The study examines the educational background of the entrepreneurs of small scale industry who are the helm of affairs and its impact on the growth of sales of the every year. Strong evidence emerges that owners of small industrial units are family concern and having a low educational background, lack of managerial knowledge and conservation-oriented attitude results in under utilization of capacity and low growth of units established every year. This research paper provides a survey of the theoretical and empirical literature relating to promote the small scale industry in the Larkana region. This study indicates effective policy measures to promote the small scale industry particularly in Larkana region and generally in Pakistan.

  15. Hyperdiffusion in non-linear, large and small-scale turbulent dynamos

    CERN Document Server

    Subramanian, K

    2003-01-01

    The generation of large-scale magnetic fields is generically accompanied by the more rapid growth of small-scale fields. The growing Lorentz force due to these fields back reacts on the turbulence to saturate the mean-field and small-scale dynamos. For the mean-field dynamo, in a quasi-linear treatment of this saturation, it is generally thought that, while the alpha-effect gets renormalised and suppressed by non-linear effects, the turbulent diffusion is left unchanged. We show here that this is not true and the effect of the Lorentz forces, is also to generate additional non-linear hyperdiffusion of the mean field. A combination of such non-linear hyperdiffusion with diffusion at small scales, also arises in a similar treatment of small-scale dynamos, and is crucial to understand its saturation.

  16. Small-scale gold mining : examples from Bolivia, Philippines and Zimbabwe

    OpenAIRE

    Jennings, Norman S

    1999-01-01

    Discusses three small-scale mining operations in Bolivia, the Philippines and Zimbabwe. Focuses on issues of health and safety, legislation, links with large mines, and the coordination of assistance.

  17. Small scale hydroelectric power potential in Nevada: a preliminary reconnaissance survey

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, G.F.; Fordham, J.W.; Richard, K.; Loux, R.

    1981-04-01

    This preliminary reconnaissance survey is intended to: develop a first estimate as to the potential number, location and characteristics of small-scale (50 kW to 15 MW) hydroelectric sites in Nevada; provide a compilation of various Federal and state laws and regulations, including tax and financing regulations, that affect small-scale hydroelectric development and provide information on sources of small-scale hydroelectric generation hardware and consultants/ contractors who do small scale hydroelectric work. The entire survey has been conducted in the office working with various available data bases. The site survey and site evaluation methods used are described, and data are tabulated on the flow, power potential, predicted capital expenditures required, etc. for 61 potential sites with measured flows and for 77 sites with derived flows. A map showing potential site locations is included. (LCL)

  18. Small-scale hydroelectric power in the Pacific Northwest: new impetus for an old energy source

    Energy Technology Data Exchange (ETDEWEB)

    1980-07-01

    Energy supply is one of the most important issues facing Northwestern legislators today. To meet the challenge, state legislatures must address the development of alternative energy sources. The Small-Scale Hydroelectric Power Policy Project of the National Conference of State Legislators (NCSL) was designed to assist state legislators in looking at the benefits of one alternative, small-scale hydro. Because of the need for state legislative support in the development of small-scale hydroelectric, NCSL, as part of its contract with the Department of Energy, conducted the following conference on small-scale hydro in the Pacific Northwest. The conference was designed to identify state obstacles to development and to explore options for change available to policymakers. A summary of the conference proceedings is presented.

  19. Regeneratively-Cooled, Turbopump-Fed, Small-Scale Cryogenic Rocket Engines Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To-date, the realization of small-scale, high-performance liquid bipropellant rocket engines has largely been limited by the inability to operate at high chamber...

  20. Small-scale production and use of wood fuels. Annual report 2007

    International Nuclear Information System (INIS)

    The 'Small-scale production and use of wood fuels' technology research programme is targeting to develop solutions which are economically competitive, reliable and acceptable in terms of emissions as regards small-scale (usually under 1 MW) wood fuel production, storage, processing, distribution and heat production. The programme aims to: 1. Develop technologies for the export market in the field of small-scale wood fuel production and use. 2. Strengthen the expertise of SMEs both in R and D and business operations. 3. Facilitate the networking of companies. 4. Improve international connections with similar companies and research institutes in order to exchange and boost specialist skills and knowledge.5. Enhance regional expertise through cooperation between the National Technology Agency and other operators. The programme supports the National Climate Strategy objective of developing competitive technological solutions to increase the small-scale use of wood by 45% by 2010

  1. Topography on Titan : New Results on Large and Small Scales

    Science.gov (United States)

    Lorenz, R. D.; Cassini Radar Team

    2011-12-01

    Although topographic coverage of Titan is and will remain sparse, some significant results have been obtained from global, regional and local measurements, via stereo, radarclinometry (shape-from-shading), autostereo (deviation from an assumed symmetric shape due to the inclined incidence), altimetry and SARtopo (monopulse) techniques. The global ellipsoidal shape (Zebker et al., 2009) provides important geophysical constraints on the interior. Hypsometry (Lorenz et al., 2011) provides insight into the balance of constructional and erosive processes and the strength of the lithosphere. Some local observations to be summarized in the talk include the measurement of mountains, the quantification of slopes that divert dunes and that drive fluid flow in river networks, as well as depth measurement of several impact craters and the assessment of candidate cryovolcanic structures. A recent new observation is a long altimetry pass T77 along the equator at the western edge of Xanadu, acquired both to constrain Titan's global shape and to understand the surface slopes and properties that may maintain the striking contrast between the dune fields of Shangri-La and the rugged and radiometrically anomalous Xanadu region. T77 also featured a SAR observation of the Ksa impact structure (discovered in SAR on T17), allowing a stereo DEM to be constructed. A feature shared by Earth and Titan is the ephemeral topography of liquids on the surface. Titan's lakes and seas likely vary in depth on geological (Myr-Gyr) and astronomical (~10 kyr) timescales : the depth of Ontario Lacus has been observed to vary on a seasonal timescale (~1 m/yr). Periodic changes of the order of 0.2-5m may occur diurnally, forced by Saturn gravitational tides. Finally, waves may be generated, at least during the windy season (which for Titan's north may be just about to begin) which can be constrained by radar and optical scattering measurements. Looking to the future, a Phase A study of the Titan Mare

  2. Small-scale quadrupole vortices in plasma with shear

    International Nuclear Information System (INIS)

    One of the outstanding problems in plasma physics today is that of explaining theoretically the experimentally observed anomalous transport of heat and particles in tokamak plasmas. For this purpose many different models have been proposed which are based on the turbulent interaction of drift waves. However, numerical experiments show that the turbulent interaction of waves in many cases gives rise to vortices. Vortices, which cause mixing of particles across the magnetic field, are objects naturally capable of producing transport effects. In this connection it is evidently useful to study the corresponding vortex structures. Kadomtsev and Pogutse have shown that anomalous electron thermal conduction arises due to processes with dimensions typically of order the collisionless skin depth δ = c/ωpe. Equations have been derived and solved describing processes on these scales; the solutions take the form of dipole vortices localized in the direction transverse to the magnetic field. Thus there is some doubt about whether such a vortex can exist in a field with shear. Exact solutions have not been found in previous treatments of shear. This neglect of the magnetic shear found in actual tokamaks is not completely correct. However, one cannot strictly say that such a vortex represents a solution found in a shear field, since there is no interaction. In the present paper an exact solution is found, in which the existence of the vortex is directly related to the presence of shear

  3. One dimensional numerical simulation of small scale CFB combustors

    Energy Technology Data Exchange (ETDEWEB)

    Gungor, Afsin [Department of Mechanical Engineering, Faculty of Engineering and Architecture, Nigde University, 51100 Nigde (Turkey)

    2009-03-15

    In this study, a one-dimensional model which includes volatilization, attrition and combustion of char particles for a circulating fluidized bed (CFB) combustor has been developed. In the modeling, the CFB combustor is analyzed in two regions: bottom zone considering as a bubbling fluidized bed in turbulent fluidization regime and upper zone core-annulus solids flow structure is established. In the bottom zone, a single-phase back-flow cell model is used to represent the solid mixing. Solids exchange, between the bubble phase and emulsion phase is a function of the bubble diameter and varies along the axis of the combustor. In the upper zone, particles move upward in the core and downward in the annulus. Thickness of the annulus varies according to the combustor height. Using the developed simulation program, the effects of operational parameters which are the particle diameter, superficial velocity and air-to-fuel ratio on net solids flux, oxygen and carbon dioxide mole ratios along the bed height and carbon content and bed temperature on the top of the riser are investigated. Simulation results are compared with test results obtained from the 50 kW Gazi University Heat Power Laboratory pilot scale unit and good agreement is observed. (author)

  4. Modeling galaxy clustering on small scales to tighten constraints on dark energy and modified gravity

    CERN Document Server

    Wang, Yun

    2016-01-01

    We present a new approach to measuring cosmic expansion history and growth rate of large scale structure using the anisotropic two dimensional galaxy correlation function (2DCF) measured from data; it makes use of the empirical modeling of small-scale galaxy clustering derived from numerical simulations by Zheng et al. (2013). We validate this method using mock catalogues, before applying it to the analysis of the CMASS sample from the Sloan Digital Sky Survey Data Release 10 (DR10) of the Baryon Oscillation Spectroscopic Survey (BOSS). We find that this method enables accurate and precise measurements of cosmic expansion history and growth rate of large scale structure. Modeling the 2DCF fully including nonlinear effects and redshift space distortions (RSD) in the scale range of 16 to 144 h^{-1}Mpc, we find H(0.57)r_s(z_d)/c=0.0459 +/- 0.0006, D_A(0.57)/r_s(z_d)=9.011 +/- 0.073, and f_g(0.57)\\sigma_8(0.57)=0.476 +/- 0.050, which correspond to precisions of 1.3%, 0.8%, and 10.5% respectively. We have defined ...

  5. Evaluation in Component Technology Small Scale Food Industry Cluster in West Sumatera

    OpenAIRE

    Gunarif Taib; Santosa Santosa; Masrul Djalal; Helmi Helmi

    2014-01-01

    The development of small-scale food industry cluster is influenced by the technology component. Because it required accurate information about the importance of existing technology components. This study aims to evaluate the technology components that are known several important factors that need to be improved so that clusters of small-scale food industries can thrive. This research using the program Analytic Hierarchy Process (AHP) to determine the level of importance of each variable based...

  6. Tanzania’s Small-Scale Sunflower Farmers: Upgrading the Value Chain

    OpenAIRE

    Enock S. Ugulumu; Eno L. Inanga

    2013-01-01

    A questionnaire using a psychometric scale investigated how small-scale sunflower farmers perceive the role of building relationships based on demand-driven upgrades, such as knowledge, skills, technology, and support services within the value chain. The study focused on small-scale sunflower farmers in the Singida region of Tanzania. The survey was conducted in twelve Agricultural Marketing Cooperatives (AMCOs) with 229 respondents. The respondents had positive opinions about creating co...

  7. Microbiological food safety of cheese produced in Swedish small-scale dairies

    OpenAIRE

    Rosengren, Åsa

    2012-01-01

    The number of small-scale dairies in Sweden has increased during the past decade. Current agricultural policy encourages such small-scale production and various ways to help producers have been proposed. Combining traditional cheese making and good product safety is a challenge, since several human pathogens pose a hazard in the products. Staphylococcus aureus is an important foodborne pathogen that can be transmitted via milk to cheese. Some strains can produce staphylococcal enterotoxin (SE...

  8. Small-scale farms in the western Brazilian Amazon: can they benefit from carbon trade?

    OpenAIRE

    Carpentier, Chantal Line; Vosti, Steve; Witcover, Julie

    2000-01-01

    Recently scientists have started to examine how land-uses and land-use technologies can help mitigate carbon emissions. The half million small-scale farmers inhabiting the Amazon frontier sequester large stocks of carbon in their forests and other land uses that they might be persuaded to maintain or even increase through the Clean Development Mechanism (CDM) of the Kyoto Protocol. On average, small-scale farmers in the Pedro Peixoto settlement project of Acre (Western Brazilian Amazon), had ...

  9. Genetically modified crops and small-scale farmers: main opportunities and challenges

    OpenAIRE

    Azadi, Hossein; Samiee, Atry; Mahmoudi, Hossein; Jouzi, Zeynab; Rafiaani Khachak, Parisa; De Maeyer, Philippe; Witlox, Frank

    2015-01-01

    Although some important features of genetically modified (GM) crops such as insect resistance, herbicide tolerance, and drought tolerance might seem to be beneficial for small-scale farmers, the adoption of GM technology by smallholders is still slight. Identifying pros and cons of using this technology is important to understand the impacts of GM crops on these farmers. This article reviews the main opportunities and challenges of GM crops for small-scale farmers in developing countrie...

  10. Women's occupational health working in small-scale agriculture in South Africa

    OpenAIRE

    Naidoo, S

    2011-01-01

    In developing economies women’s contributions are in agriculture. Trends indicate that women’s participation in small-scale agriculture is increasing. On the Makhatini Flats in northern KwaZulu-Natal intensive small-scale farming takes place with > 4 000 women involved. A cross-sectional study on the Irrigation Scheme and Drylands areas of the Makhatini Flats described and compared occupational activities, crop production, pesticide use and adverse health outcomes among women working in small...

  11. An Integrated Assessment Approach to Address Artisanal and Small-Scale Gold Mining in Ghana

    OpenAIRE

    Niladri Basu; Renne, Elisha P.; Rachel N. Long

    2015-01-01

    Artisanal and small-scale gold mining (ASGM) is growing in many regions of the world including Ghana. The problems in these communities are complex and multi-faceted. To help increase understanding of such problems, and to enable consensus-building and effective translation of scientific findings to stakeholders, help inform policies, and ultimately improve decision making, we utilized an Integrated Assessment approach to study artisanal and small-scale gold mining activities in Ghana. Thou...

  12. Basic principles of taxation of small-scale enterprises in the Russian Federation

    OpenAIRE

    Khodyreva Viktoriia Andreevna

    2015-01-01

    This research is devoted to general principles of taxation of small-scale enterprises. Development of small-scale enterprises is one of the most important lines of tax policy in Russian Federation. The development of principles of taxation is important while forming a strong state system of taxation. In this work basic principles and some specific are provided. This work is of great scientific interest to law students, graduates, teachers and other persons interested in law and particularly i...

  13. Design and testing of small-scale thin-film palm oil refinery

    OpenAIRE

    Kooptanond, C.; Wanichwiriya, S.; Limworaphan, C.; Klinpikul, S.

    2000-01-01

    The design and testing improvement of a small-scale palmoil refinery was carried out as a continuity of the development of palmoil refinery under the Royal Project for promotion of Small-scale Palmoil Industry. The intended objective is to develop a continuous palmoil refining process which has a higher effeciency than the existing batch refining process. The thin-film refining thechnique was selected among various semi-continuous and continuous refining processes. A pilot palmoil refinery at...

  14. Correlation between large- and small-scale velocity components under Fourier filters

    Directory of Open Access Journals (Sweden)

    Le Fang

    2014-01-01

    Full Text Available By introducing the Fourier filters, we analyse the correlation between large- and small-scale velocity components in homogeneous isotropic turbulence theoretically. We show that different Fourier filters act similarly on this multi-scale correlation with a “natural” mechanism of removing the physical correlations between large- and small-scale velocity components. This conclusion calls for the further investigation on the Hilbert—Huang decomposition to investigate the mechanism of Marusic et al (2008.

  15. Measurements on the small scale Sterrebeek and full scale Herzele test sections in Belgium

    OpenAIRE

    BERGIERS, Anneleen; GOUBERT, Luc; Cesbron, Julien

    2015-01-01

    Two small scale 'pilot' test sections have been constructed in Sterrebeek on a private road without traffic to gain experience with the construction method. These construction works demonstrated that a 'regular' asphalt paver can be used for onsite PERS constructions. Then a full scale test track has been constructed on a road with regular traffic in Herzele. The result of the first small scale construction was an inhomogeneous test section as the mix hardened too quickly and the construct...

  16. Government Policies on Small Scale Poultry Business and Environmental Health in Indonesia

    OpenAIRE

    Nyak Ilham

    2015-01-01

    The government paid great attention to develop small-scale poultry business, to reduce poverty alleviation and increase employment opportunities. The government has established various policies to encourage the growth of poultry production cluster (PPC) in rural areas. However, the fact shows that these policies have not been able to solve the problems. Small-scale poultry business is particularly vulnerable to economic changes, including animal diseases. The economic crisis of 1997-1998 and ...

  17. Forest certification as an instrument for improved forest management within small-scale forestry

    OpenAIRE

    Lidestav, Gun; Berg Lejon, Solveig

    2011-01-01

    Since early 1990 ties, Swedish forest land is increasingly becoming certified. Today all major forest owners have joined the Swedish FSC-standard (Forest Stewardship Council), while small-scale forest owners preferably are joining the PEFC scheme (Programme for the Endorsement of Forest Certification). With the overall aim of gaining a better insight into which small-scale forest owners that have decided to take up on forest certification, and how their forest management practices have been a...

  18. A small scale magnetically levitated train for project-based laboratory education

    OpenAIRE

    Glehn Gregor; Appunn Rüdiger; Hameyer Kay

    2015-01-01

    The drive train of a small scale magnetically levitated train reveals the principles of a mechatronic system and offers challenges related to design, construction and control. Therefore, it is used at the Institute of electrical Machines (IEM) of the RWTH Aachen University as a demonstrator for engineering solutions. Instead of being a part of a static predefined student laboratory, the small scale magnetically levitated train is part of dynamic individual student projects. This approach prov...

  19. Marketing strategy for retailing small-scale wind energy turbines in Indian markets

    OpenAIRE

    Harjula, Nina

    2009-01-01

    The study analyzes the small-scale wind energy markets in Mumbai, focusing on questions: How feasible is the wind energy for SME businesses in Mumbai, and what are the main challenges and opportunities of small-scale wind energy in Mumbai? The study is a qualitative case study, in which, the data has been collected through observing the markets by visiting wind energy sites and companies, interviewing and meeting potential customers and other stakeholders in the market. Theoretical frame...

  20. Small-scale irrigation dams, agricultural production, and health - theory and evidence from Ethiopia

    OpenAIRE

    Ersado, Lire

    2005-01-01

    The author looks at the feasibility and potential of instituting small-scale irrigation dams to reduce Ethiopia s dependence on rainfed agriculture and the associated food insecurity. He develops a theoretical framework to assess the welfare implications of irrigation development programs and provides empirical evidence from microdam construction and reforestation projects in northern Ethiopia. The author pays particular attention to health-related costs of establishing small-scale irrigation...

  1. FarmLime: Low-cost lime for small-scale farming

    OpenAIRE

    Mitchell, C. J.

    2005-01-01

    FarmLime (Low-cost lime for small-scale farming) is a multidisciplinary research project that aims to increase the food security of small-scale farmers by improving their access to agricultural lime which neutralises soil acidity and adds nutrients. This project focused on farming districts in northern Zambia that have highly acidic soils with poor crop yields. The aim was to locate suitable carbonate rocks in these farming districts and produce agricultural lime using a low cost method, elim...

  2. Organic and alike farming in Latin America: state and relevance for small-scale livestock keepers

    OpenAIRE

    Siegmund-Schultze, Marianna; Valle Zárate, Anne

    2007-01-01

    While the organic movement is growing, its contribution to small-scale livestock farm-ing in Latin America is contentious. Secondary literature and available statistics were used for this study. Farms and area under certified organic agriculture are rising, but small-scale livestock farming is little represented. The latter is yet to be found in non-certified organic-like farms, offering locally adapted paths to securing livelihoods.

  3. Rural Small Scale Enterprises in Zambia: Results of a 1985 Country-Wide Survey

    OpenAIRE

    Milimo, John T.; Fisseha, Yacob

    1986-01-01

    This paper reports on the results of a nationwide survey of small scale enterprises in Zambia conducted during 1985. The survey was undertaken in the rural and semi-urban (population below 50,000) localities of the country except for those in the Copperbelt and Lusaka provinces. All small scale non-farm enterprises employing 50 people or less and operating from a fixed location in these areas were included.

  4. Inclusion of small-scale milk producers in modern dairy value chains

    OpenAIRE

    Wouters, A.P.; Lee(이복, Bok-Rye, 례)

    2010-01-01

    The worldwide demand for milk is ever-increasing. The question we address here is how small-scale milk producers, mainly based in developing countries, can participate in modern dairy value chains? First, markets should have the preconditions of a reliable market, a competitive milk price and access to essential services and inputs. Second, small-scale producers need to improve farm management practices (feeding, breeding, control animal diseases) to become economically and environmentally mo...

  5. A Methodological Approach to Evaluate Livestock Innovations on Small-Scale Farms in Developing Countries

    OpenAIRE

    Antón García-Martínez; José Rivas-Rangel; Jaime Rangel-Quintos; José Antonio Espinosa; Cecilio Barba; Carmen de-Pablos-Heredero

    2016-01-01

    The aim of the study was deepening the knowledge of livestock innovations knowledge on small-scale farms in developing countries. First, we developed a methodology focused on identifying potential appropriate livestock innovations for smallholders and grouped them in innovation areas, defined as a set of well-organized practices with a business purpose. Finally, a process management program (PMP) was evaluated according to the livestock innovation level and viability of the small-scale farms....

  6. Farming of rabbit local breed as an alternative activity on small scale farms in Albania

    OpenAIRE

    Llambiri A.; Papa L.; Kume K.

    2010-01-01

    Rabbit breeding on small scale family farms is carried on as an alternative production activity, in Albania. Extensive production system and breeding of local rabbit breed are most frequent. Albanian local rabbit can be classified in middle size breed group. It is a population with high morphological and biological variability, with variation in coat colour. Rabbit farming is a useful production activity on small scale family farms. Breeding 2-3 couples of reproducing rabbits could increase t...

  7. Application of Heterogeneous Catalysis in Small-Scale Biomass Combustion Systems

    OpenAIRE

    Christian Thiel; Mirjam Matthes; Ingo Hartmann; Saad Butt; René Bindig

    2012-01-01

    Combustion of solid biomass fuels for heat generation is an important renewable energy resource. The major part among biomass combustion applications is being played by small-scale systems like wood log stoves and small wood pellet burners, which account for 75% of the overall biomass heat production. Despite an environmentally friendly use of renewable energies, incomplete combustion in small-scale systems can lead to the emission of environmental pollutants as well as substances which are h...

  8. Factors affecting Small-Scale Coffee Production in Githunguri District, Kenya

    OpenAIRE

    Margaret Njeri Gathura

    2013-01-01

    This study was carried out to determine the factors affecting small scale coffee production in Kenya. The establishments under study were small-scale coffee farms in Githunguri District.It was to determine whether marketing factors, finances, government policies and physical and human resources affect coffee production in Githunguri District. Primary sources included use of questionnaires, observation and interviews. Secondary sources included desk research, library research on journals, text...

  9. INFORMATION NEEDS FOR SMALL SCALE MINERS (SSM): A CASE OF TAITA TAVETA COUNTY, KENYA

    OpenAIRE

    John Lugovane; Bernard K. Rop

    2014-01-01

    This study examines information needs for Small Scale Miners (SSM) in Taita Taveta County in the Coastal region of Kenya. The geological and mineral resources technical reports of the region indicate the presence of deposits of globally known gemstones such as Ruby, Tsavorite, Sapphire, Emerald and garnets. Industrial minerals include iron-ore, limestones, magnesite and graphite. There are many Small Scale Miners (SSM) and medium sized mineral prospecting companies operating i...

  10. Effective Utilization of a Small-Scale Municipal Solid Waste for Power Generation

    OpenAIRE

    A. J. Ujama; F. Ebohb; T.O.Chimec

    2013-01-01

    Quantity of small scale municipal solid waste available in each of the states of Nigeria was assessed and determined. Physical and Chemical characteristics of the various types of solid wastes were analysed and their values estimated. Thermal analysis of a small-scale municipal solid waste-fired steam generator was done. The analysis was based on the selected design parameters: operating steam pressure of 10 bar, with fuel consumption rate of 500 Kg/h and combustion chamber which utilizes mas...

  11. Effect of small-scale baryon inhomogeneity on cosmic nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kurki-Suonio, H.; Matzner, R.A.

    1989-02-15

    We consider the evolution of the nuclear abundances in a universe with inhomogeneities (induced by the quark-hadron phase transition) on a scale such that neutron diffusion is important before and during nucleosynthesis. We investigate a number of initial baryon density contrast ratios: R = 10, 100, 1000; a number of high-density volume fractions: f/sub V/ = (1/4, (1/8, (1/16, and (1/64; and a number of geometries: planar, cylindrical with the higher density near the center, cylindrical with the higher density near the outer zone of computation (thin-walled tubes of higher density), spherical with the higher density near the center (isolated spherical regions of high density), and spherical with the higher density near the outer zones of the computation (a foam structure of high-density regions). We concentrate on three R = 100 models. For a high-density (eta = 70 x 10/sup -10/equivalentrho/sub baryon/(now) = 4.3 x 10/sup -30/ g cm/sup -3/) universe that would be closed for Hubble parameter H/sub 0/ = 50 km/sec Mpc, we find disagreement in all three isotopes (/sup 2/H, /sup 4/He, /sup 7/Li) with observations, regardless of the scale r/sub i/ of the inhomogeneity; for eta = 3 x 10/sup -10/ and eta = 7 x 10/sup -10/, ''low''- and ''high''-standard values (eta = 3 x 10/sup -10/ corresponds in the homogeneous case to the absolute minimum of /sup 7/Li production), we find that for inhomogeneity distance scales typical of those expected at the quark-hadron transition, i.e., r/sub i/approx. <100 m, then /sup 4/He and /sup 2/H abundances remain in agreement with observational values, and /sup 7/Li is also not much changed from its value in a homogeneous cosmology.

  12. Health and Safety Management for Small-scale Methane Fermentation Facilities

    Science.gov (United States)

    Yamaoka, Masaru; Yuyama, Yoshito; Nakamura, Masato; Oritate, Fumiko

    In this study, we considered health and safety management for small-scale methane fermentation facilities that treat 2-5 ton of biomass daily based on several years operation experience with an approximate capacity of 5 t·d-1. We also took account of existing knowledge, related laws and regulations. There are no qualifications or licenses required for management and operation of small-scale methane fermentation facilities, even though rural sewerage facilities with a relative similar function are required to obtain a legitimate license. Therefore, there are wide variations in health and safety consciousness of the operators of small-scale methane fermentation facilities. The industrial safety and health laws are not applied to the operation of small-scale methane fermentation facilities. However, in order to safely operate a small-scale methane fermentation facility, the occupational safety and health management system that the law recommends should be applied. The aims of this paper are to clarify the risk factors in small-scale methane fermentation facilities and encourage planning, design and operation of facilities based on health and safety management.

  13. Ethnographic Approaches to Understanding Social Sustainability in Small-scale Water Systems

    Science.gov (United States)

    Wutich, A.

    2011-12-01

    Social sustainability is an important, but often neglected, aspect of determining the success of small-scale water systems. This paper reviews ethnographic approaches for understanding how indigenous knowledge enhances social sustainability of small-scale water systems, particularly in small-scale water systems threatened by water scarcity. After reviewing the literature on common-pool and traditional resource management strategies, the paper will focus on the case of a community-managed small-scale water system in Cochabamba, Bolivia. This study uses ethnographic evidence to demonstrate how indigenous institutions can be used to manage a small-scale urban water system sustainably. Several factors were crucial to the institution's success. First, indigenous residents had previous experience with common management of rural irrigation systems which they were able to adapt for use in an urban environment. Second, institutional rules were designed to prioritize the conservation of the water source. Third, indigenous Andean social values of uniformity, regularity, and transparency ensured that community members perceived the system as legitimate and complied with community rules. Fourth, self-governance enabled community members to quickly adapt to changing environmental conditions, such as seasonal scarcity and groundwater overdraft. The paper concludes with a discussion of the promise and limitations of ethnographic approaches and indigenous knowledge for understanding social sustainability in small-scale water systems.

  14. Small-scale hydro-electric scheme in Roches, Switzerland

    International Nuclear Information System (INIS)

    The small hydropower plant (SHPP) project 'PCH Roches' is planned to be built in Roches, a small village located in the Jura region of the canton of Bern. The goal of this undertaking is to reactivate a site with hydro potential of the river Birs on a section that was already well exploited by some ancient SHPP (since 1953 or probably even earlier). Several modifications were performed on this plant over the years; not all contributed positively on its production figures. Following a transfer of the water rights in 1987, claims became loud against the owner to perform maintenance on the river banks and to modify the weir such that a free passage for the fishes will be granted. Those issues contributed to inflate a conflict which ended in the repeal of the water rights and a total plant shut down in 2001. The new project plans to reuse the existing pen stock and to carry out some refurbishing activities to grant security and better performance. The weir and the intake structure are also redesigned such that the water storage can be somewhat raised for normal operation; a weir gate will however allow to better discharge the river in flood situations. A new turbine house will be erected at the current location where the tail water pen stock rejoins the river. Hence, the existing old turbine house will be obsolete and the upper and lower pen stock sections are to be linked with each other. Limited by the existing pen stock size, the new plant is expected to produce some 50 kW power and 362,000 kWh/year. This represents an increase in energy generation of around 200% compared with the ancient SHPP. Gross head is 5.38 m, net head 4.12 m with a turbine flow of at least 1.6 m3/s. The expected energy sales price applicable to this project reaches about 0.17 CHF/kWh as per the current tariffs set by the grid owner. This project calls for the building of a state-of-the-art SHPP. It will avoid the total dismantling of the existing works to take place and allow the small

  15. Irradiation facilities for materials research: IFMIF and small scale installations

    International Nuclear Information System (INIS)

    The research of advance materials in nuclear fields such as new fission reactors (Generation-IV), Accelerator Driven Systems for Transmutation of Radioactive Wastes and Nuclear Fusion, is becoming very much common in the types of low activation and radiation resistant Materials. Ferritic-Martensitic Steels (based in 9-12 Cr) with or without Oxide Dispersion Techniques (Ytria Nanoparticles), Composites materials are becoming the new generation to answer requirements of high temperature, high radiation resistance of structural materials. Special dedication is appearing in general research programmes to this area of Materials. The understanding of their final performance needs a wider knowledge of the mechanisms of radiation damage in these materials from the atomistic scale to the macroscopic responses. New extensive campaigns are being funded to irradiate from simple elements to model alloys and finally the complex materials themselves. That sequence and its state of art will be presented One clear technique for that understanding is the Multi scale Modelling which includes simulation techniques from quantum mechanics, molecular dynamics, defects diffusion, mesoscopic modelling and finally the macroscopic constitutive relations for macroscopic analysis. However, in each one of these steps is necessary a systematic and well established program of experiments that combines the irradiation and the very detailed analysis with techniques such as Transmission Electron Microscope, Positron Annihilation, SIMS, Atom Probe, Nanoindebntation. A key aspect that wants to be presented in this work is the state of art and discussion of Irradiation Facilities for Materials studies. Those facilities goes from ion implantation sources, small accelerator, Experimental Reactors such High Flux Reactor, sophisticated Triple Beams Sources as JANNUS in France to generate at the same time displacements-hydrogen-helium, and projected very large neutron installation such as IFMIF. The role to

  16. Factors Influencing Potential Acceptance and Adoption of Clean Development Mechanism Projects: Case of Carbon Trade Tree Project among Small Scale Farmers in Njoro District, Kenya

    OpenAIRE

    Oscar I. Ayuya; Job K. Lagat and John M. Mironga

    2011-01-01

    The aim of study was to assess the willingness of small scale farmers to accept and the extent of willingness to adopt carbon trade tree project and by so doing to identify and quantify factors that will influence adoption of carbon trade tree project. The study used multi-stage sampling procedure to select 150 small-scale farmers in Njoro district, Kenya. Both primary and secondary data sources collected using observations and interviews with the help of a semi-structured questionnaire. The ...

  17. Injury Profiles Associated with Artisanal and Small-Scale Gold Mining in Tarkwa, Ghana

    Directory of Open Access Journals (Sweden)

    Benedict N. L. Calys-Tagoe

    2015-07-01

    Full Text Available Artisanal and small-scale gold mining (ASGM is inherently risky, but little is known about mining-associated hazards and injuries despite the tremendous growth worldwide of ASGM and the benefits it offers. The current study aimed to characterize the physical injuries associated with ASGM in Ghana to guide policy formulation. A cross-sectional survey was carried out in the Tarkwa mining district of the Western Region of Ghana in 2014. A total of 404 small-scale miners were recruited and interviewed regarding their occupational injury experiences over the preceding 10 years using a paper-based structured questionnaire. Nearly one-quarter (23.5% of the miners interviewed reported getting injured over the previous 10 years, and the overall injury rate was calculated to be 5.39 per 100 person years. The rate was significantly higher for women (11.93 per 100 person years and those with little mining experience (e.g., 25.31 per 100 person years for those with less than one year of work experience. The most injury-prone mining activities were excavation (58.7% and crushing (23.1%, and over 70% of the injuries were reported to be due to miners being hit by an object. The majority of the injuries (57% were lacerations, and nearly 70% of the injuries were to the upper or lower limbs. Approximately one-third (34.7% of the injuries resulted in miners missing more than two weeks of work. One-quarter of the injured workers believed that abnormal work pressure played a role in their injuries, and nearly two-fifths believed that their injuries could have been prevented, with many citing personal protective equipment as a solution. About one-quarter of the employees reported that their employers never seemed to be interested in the welfare or safety of their employees. These findings greatly advance our understanding of occupational hazards and injuries amongst ASGM workers and help identify several intervention points.

  18. Factors influencing the use of improved farm practices among small-scale farmers in Kano State of Nigeria

    OpenAIRE

    Oyewole S. O.; Ojeleye O. A.

    2015-01-01

    This study evaluates the factors influencing the use of improved farm practices among small-scale farmers in Kano State. Data were obtained from 110 farmers with the aid of structured questionnaire. Data were analysed using descriptive statistics and multiple regression analysis. The results showed that 73.6 of the respondents are in the range of 20 to 50 years which is the active age range. The mean age of respondents was 40 years. It was revealed that 80.9% of the respondents have farming e...

  19. Assessment of the implementation issues for fuel cells in domestic and small scale stationary power generation and CHP applications

    Energy Technology Data Exchange (ETDEWEB)

    Graham, G.; Cruden, A.; Hart, J.

    2002-07-01

    This report discusses implementation issues associated with the use of fuel cells in <10 kW domestic, small-scale power generation and combined heat and power (CHP) operations in the UK. The report examines the key issues (fuel cell system standards and certification, fuel infrastructure, commercial issues and competing CHP technologies), before discussing non-technical issues including finance, ownership, import and export configuration, pricing structure, customer acceptability, installation, operation and training of servicing and commissioning personnel. The report goes on to discuss market and technical drivers, grid connection issues and solutions, operations and maintenance. Recommendations for the future are made.

  20. Wave Pressures and Loads on a Small Scale Model of the Svåheia SSG Pilot Project

    DEFF Research Database (Denmark)

    Buccino, Mariano; Vicinanza, Diego; Ciardulli, Francesco;

    2011-01-01

    The paper reports on 2D small scale experiments conducted to investigate wave loadings acting on a pilot project of device for the conversion of wave energy into electricity. The conversion concept is based on the overtopping principle and the structure is worldwide known with the acronym SSG. The...... hydraulic model tests have been carried out at the LInC laboratory of the University of Naples Federico II using random waves. Results indicate wave overtopping is able to cause a sudden inversion of vertical force under wave crest, so that it is alternatively upward and downward directed over a short time...

  1. SMALL-SCALE ENVIRONMENTAL GRADIENTS IN A PINE-OAK FOREST COMMUNITY IN NUEVA COLONIA, MEZQUITIC, JALISCO, MEXICO

    OpenAIRE

    Gregorio Nieves-Hernández; J. Antonio Vázquez-García; Yalma L. Vargas- Rodriguez; Marcelino Vázquez-García; Jesús González-Gallegos

    2009-01-01

    We explored environmental variables related to pine-oak forest community structure at one locality in Jalisco, Mexico. We used an NMS ordination in conjunction with the Sørensen distance to identify the major small-scale community gradients along 25 contiguous quadrats (25 m x 25 m, 400 m2 each) of pine-oak forest in Nueva Colonia, Mezquitic, Jalisco, Mexico. The main matrix (25 stands x 7 tree species) included basal area data, and the environmental matrix consisted of 19 quantitative enviro...

  2. Hubble Space Telescope search for the transit of the Earth-mass exoplanet Alpha Centauri Bb

    CERN Document Server

    Demory, Brice-Olivier; Queloz, Didier; Seager, Sara; Gilliland, Ronald; Chaplin, William J; Proffitt, Charles; Gillon, Michael; Guenther, Maximilian N; Benneke, Bjoern; Dumusque, Xavier; Lovis, Christophe; Pepe, Francesco; Segransan, Damien; Triaud, Amaury; Udry, Stephane

    2015-01-01

    Results from exoplanet surveys indicate that small planets (super-Earth size and below) are abundant in our Galaxy. However, little is known about their interiors and atmospheres. There is therefore a need to find small planets transiting bright stars, which would enable a detailed characterisation of this population of objects. We present the results of a search for the transit of the Earth-mass exoplanet Alpha Centauri Bb with the Hubble Space Telescope (HST). We observed Alpha Centauri B twice in 2013 and 2014 for a total of 40 hours. We achieve a precision of 115 ppm per 6-s exposure time in a highly-saturated regime, which is found to be consistent across HST orbits. We rule out the transiting nature of Alpha Centauri Bb with the orbital parameters published in the literature at 96.6% confidence. We find in our data a single transit-like event that could be associated to another Earth-size planet in the system, on a longer period orbit. Our program demonstrates the ability of HST to obtain consistent, hi...

  3. The Kapteyn moving group is not tidal debris from $\\omega$ Centauri

    CERN Document Server

    Navarrete, Camila; Ramírez, Iván; Meza, Andrés; Anglada-Escudé, Guillem; Shkolnik, Evgenya

    2015-01-01

    The Kapteyn moving group has been postulated as tidal debris from $\\omega$ Centauri. If true, members of the group should show some of the chemical abundance patterns known for stars in the cluster. We present an optical and near-infrared high-resolution, high-S/N spectroscopic study of 14 stars of the Kapteyn group, plus 10 additional stars (the $\\omega$ Cen-group) that, while not listed as members of the Kapteyn group as originally defined, have been nevertheless associated dynamically with $\\omega$ Centauri. Abundances for Na, O, Mg, Al, Ca and Ba were derived from the optical spectra, while the strength of the chromospheric He I 10830 {\\AA} line is studied as a possible helium abundance indicator. The resulting Na-O and Mg-Al patterns for stars of the combined Kapteyn and $\\omega$ Cen-group samples do not resemble those of $\\omega$ Centauri, and are not different from those of field stars of the Galactic halo. The distribution of equivalent widths of the He I 10830 {\\AA} line is consistent with that found...

  4. Radiative 3D MHD simulations of the spontaneous small-scale eruptions in the solar atmosphere

    Science.gov (United States)

    Kitiashvili, Irina N.

    2015-08-01

    Studying non-linear turbulent dynamics of the solar atmosphere is important for understanding mechanism of the solar and stellar brightness variations. High-resolution observations of the quiet Sun reveal ubiquitous distributions of high-speed jets, which are transport mass and energy into the solar corona and feeding the solar wind. However, the origin of these eruption events is still unknown. Using 3D realistic MHD numerical simulations we find that small-scale eruptions are produced by ubiquitous magnetized vortex tubes generated by the Sun's turbulent convection in subsurface layers. The swirling vortex tubes (resembling tornadoes) penetrate into the solar atmosphere, capture and stretch background magnetic field, and push the surrounding material up, generating shocks. Our simulations reveal complicated high-speed flow patterns and thermodynamic and magnetic structure in the erupting vortex tubes and shows that the eruptions are initiated in the subsurface layers and are driven by high-pressure gradients in the subphotosphere and photosphere and by the Lorentz force in the higher atmosphere layers. I will discuss about properties of these eruptions, their effects on brightness and spectral variations and comparison with observations.

  5. Theory of azimuthally small-scale hydromagnetic waves in the axisymmetric magnetosphere with finite plasma pressure

    Directory of Open Access Journals (Sweden)

    D. Y. Klimushkin

    Full Text Available The structure of monochromatic MHD-waves with large azimuthal wave number m≫1 in a two-dimensional model of the magnetosphere has been investigated. A joint action of the field line curvature, finite plasma pressure, and transversal equilibrium current leads to the phenomenon that waves, standing along the field lines, are travelling across the magnetic shells. The wave propagation region, the transparency region, is bounded by the poloidal magnetic surface on one side and by the resonance surface on the other. In their meaning these surfaces correspond to the usual and singular turning points in the WKB-approximation, respectively. The wave is excited near the poloidal surface and propagates toward the resonance surface where it is totally absorbed due to the ionospheric dissipation. There are two transparency regions in a finite-beta magnetosphere, one of them corresponds to the Alfvén mode and the other to the slow magnetosound mode.

    Key words. Magnetosphere · Azimuthally small-scale waves · MHD waves

  6. Irreversible Wash Aid Additive for Cesium Mitigation. Small-Scale Demonstration and Lessons Learned

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Michael [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-01-01

    The Irreversible Wash Aid Additive process has been under development by the U.S. Environmental Protection Agency (EPA) and Argonne National Laboratory (Argonne). This process for radioactive cesium mitigation consists of a solution to wash down contaminated structures, roadways, and vehicles and a sequestering agent to bind the radionuclides from the wash water and render them environmentally immobile. The purpose of this process is to restore functionality to basic services and immediately reduce the consequences of a radiologically-contaminated urban environment. Research and development have resulted in a down-selection of technologies for integration and demonstration at the pilot-scale level as part of the Wide Area Recovery and Resiliency Program (WARRP) under the Department of Homeland Security and the Denver Urban Area Security Initiative. As part of developing the methods for performing a pilot-scale demonstration at the WARRP conference in Denver in 2012, Argonne conducted small-scale field experiments at Separmatic Systems. The main purpose of these experiments was to refine the wash water collection and separations systems and demonstrate key unit operations to help in planning for the large scale demonstration in Denver. Since the purpose of these tests was to demonstrate the operations of the system, we used no radioactive materials. After a brief set of experiments with the LAKOS unit to familiarize ourselves with its operation, two experiments were completed on two separate dates with the Separmatic systems.

  7. Regulatory potential for increasing small scale grid connected photovoltaic (PV) deployment in Australia

    International Nuclear Information System (INIS)

    The last decade has seen significant innovation and change in regulatory incentives to support photovoltaic deployment globally. With high fossil fuel dependency and abundant solar resource availability in Australia, grid connected photovoltaics are a viable low carbon technology option in existing electricity grids. Drawing on international examples, the potential to increase grid PV deployment through government response and regulation is explored. For each renewable energy certificate (REC) earned by small scale photovoltaics until 2012, the market provides four additional certificates under the current banded renewable targets. Our analysis indicates that REC eligibility is not accurately estimated currently, and an energy model is developed to calculate the variance. The energy model estimates as much as 26% additional REC's to be obtained by a 3 kWp PV system, when compared to the currently used regulatory method. Moreover, the provision of REC's increases benefits to PV technologies, in the process distorting CO2 abatement (0.21 tonne/REC) by 68%, when PV displaces peaking natural gas plants. Consideration of the secondary effects of a banded structure on emissions trading market is important in the context of designing a range of initiatives intended to support a transition to a low carbon electricity sector. (author)

  8. Signatures of magnetic reconnection at boundaries of interplanetary small-scale magnetic flux ropes

    CERN Document Server

    Tian, Hui; Zong, Qiugang; He, Jiansen; Qi, Yu

    2010-01-01

    The interaction between interplanetary small-scale magnetic flux ropes and the magnetic field in the ambient solar wind is an important topic to understand- ing the evolution of magnetic structures in the heliosphere. Through a survey of 125 previously reported small flux ropes from 1995 to 2005, we find that 44 of them reveal clear signatures of Alfvenic fluctuations, and thus classify them into Alfven wave trains rather than flux ropes. Signatures of magnetic reconnection, generally including a plasma jet of ~30 km/s within a magnetic field rotational region, are clearly present at boundaries of about 42% of the flux ropes and 14% of the wave trains. The reconnection exhausts are often observed to show a local increase in the proton temperature, density and plasma beta. About 66% of the reconnection events at flux rope boundaries are associated with a magnetic field shear angle larger than 90 deg and 73% of them reveal a decrease by 20% or more in the magnetic field magnitude, suggesting a dominance of anti...

  9. Distinct soil bacterial communities along a small-scale elevational gradient in alpine tundra

    Directory of Open Access Journals (Sweden)

    Congcong eShen

    2015-06-01

    Full Text Available The elevational diversity pattern for microorganisms has received great attention recently but is still understudied, and phylogenetic relatedness is rarely studied for microbial elevational distributions. Using a bar-coded pyrosequencing technique, we examined the biodiversity patterns for soil bacterial communities of tundra ecosystem along 2000–2500 m elevations on Changbai Mountain in China. Bacterial taxonomic richness displayed a linear decreasing trend with increasing elevation. Phylogenetic diversity and mean nearest taxon distance (MNTD exhibited a unimodal pattern with elevation. Bacterial communities were more phylogenetically clustered than expected by chance at all elevations based on the standardized effect size of MNTD metric. The bacterial communities differed dramatically among elevations, and the community composition was significantly correlated with soil total carbon, total nitrogen, C:N ratio, and dissolved organic carbon. Multiple ordinary least squares regression analysis showed that the observed biodiversity patterns strongly correlated with soil total carbon and C:N ratio. Taken together, this is the first time that a significant bacterial diversity pattern has been observed across a small-scale elevational gradient. Our results indicated that soil carbon and nitrogen contents were the critical environmental factors affecting bacterial elevational distribution in Changbai Mountain tundra. This suggested that ecological niche-based environmental filtering processes related to soil carbon and nitrogen contents could play a dominant role in structuring bacterial communities along the elevational gradient.

  10. Summary of Large-and Small-Scale Unreinforced Masonry Test Program

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, K.E.

    2002-06-28

    A five-year, large- and small-scale, static and dynamic experimental research program, in which more than 700 tests were conducted, has demonstrated that unreinforced masonry infills are more ductile and resist lateral loads more effectively than anticipated by conventional code procedures. The tests were conducted both in the laboratory and on existing structures at the Department of Energy's Y-12 National Security Complex. The experimental data indicate that the combination of a steel frame and infill material efficiently resists lateral loads--the infilling provides significant lateral stiffness while the surrounding frame adds ductility and confinement to the overall system. The results from approximately 25 moderate- and full-scale tests on infills showed that with simulated seismic loads, the frames confined the masonry, and the load-carrying capacity of the infill was considerably above the load that caused initial cracking. This finding was a significant departure from classical code approaches that assumed first cracking to be failure of an unreinforced masonry wall. The experimental program, performed for the US Department of Energy, consisted of the following large-scale tests on infills: in situ airbag pressure testing, shake-table tests, and the application of quasi-static in-plane and out-of-plane drift loads. This paper provides a summary of the overall experimental methodology and results.

  11. Irreversible Wash Aid Additive for Cesium Mitigation. Small-Scale Demonstration and Lessons Learned

    International Nuclear Information System (INIS)

    The Irreversible Wash Aid Additive process has been under development by the U.S. Environmental Protection Agency (EPA) and Argonne National Laboratory (Argonne). This process for radioactive cesium mitigation consists of a solution to wash down contaminated structures, roadways, and vehicles and a sequestering agent to bind the radionuclides from the wash water and render them environmentally immobile. The purpose of this process is to restore functionality to basic services and immediately reduce the consequences of a radiologically-contaminated urban environment. Research and development have resulted in a down-selection of technologies for integration and demonstration at the pilot-scale level as part of the Wide Area Recovery and Resiliency Program (WARRP) under the Department of Homeland Security and the Denver Urban Area Security Initiative. As part of developing the methods for performing a pilot-scale demonstration at the WARRP conference in Denver in 2012, Argonne conducted small-scale field experiments at Separmatic Systems. The main purpose of these experiments was to refine the wash water collection and separations systems and demonstrate key unit operations to help in planning for the large scale demonstration in Denver. Since the purpose of these tests was to demonstrate the operations of the system, we used no radioactive materials. After a brief set of experiments with the LAKOS unit to familiarize ourselves with its operation, two experiments were completed on two separate dates with the Separmatic systems.

  12. "Economic man" in cross-cultural perspective: behavioral experiments in 15 small-scale societies.

    Science.gov (United States)

    Henrich, Joseph; Boyd, Robert; Bowles, Samuel; Camerer, Colin; Fehr, Ernst; Gintis, Herbert; McElreath, Richard; Alvard, Michael; Barr, Abigail; Ensminger, Jean; Henrich, Natalie Smith; Hill, Kim; Gil-White, Francisco; Gurven, Michael; Marlowe, Frank W; Patton, John Q; Tracer, David

    2005-12-01

    Researchers from across the social sciences have found consistent deviations from the predictions of the canonical model of self-interest in hundreds of experiments from around the world. This research, however, cannot determine whether the uniformity results from universal patterns of human behavior or from the limited cultural variation available among the university students used in virtually all prior experimental work. To address this, we undertook a cross-cultural study of behavior in ultimatum, public goods, and dictator games in a range of small-scale societies exhibiting a wide variety of economic and cultural conditions. We found, first, that the canonical model - based on self-interest - fails in all of the societies studied. Second, our data reveal substantially more behavioral variability across social groups than has been found in previous research. Third, group-level differences in economic organization and the structure of social interactions explain a substantial portion of the behavioral variation across societies: the higher the degree of market integration and the higher the payoffs to cooperation in everyday life, the greater the level of prosociality expressed in experimental games. Fourth, the available individual-level economic and demographic variables do not consistently explain game behavior, either within or across groups. Fifth, in many cases experimental play appears to reflect the common interactional patterns of everyday life. PMID:16372952

  13. Sediment depositions upstream of open check dams: new elements from small scale models

    Science.gov (United States)

    Piton, Guillaume; Le Guern, Jules; Carbonari, Costanza; Recking, Alain

    2015-04-01

    numbers that the flows tend to adopt? New small scale model experiments have been undertaken focusing on depositions processes and their related hydraulics. Accurate photogrammetric measurements allowed us to better describe the deposition processes3. Large Scale Particle Image Velocimetry (LS-PIV) was performed to determine surface velocity fields in highly active channels with low grain submersion4. We will present preliminary results of our experiments showing the new elements we observed in massive deposit dynamics. REFERENCES 1.Armanini, A., Dellagiacoma, F. & Ferrari, L. From the check dam to the development of functional check dams. Fluvial Hydraulics of Mountain Regions 37, 331-344 (1991). 2.Piton, G. & Recking, A. Design of sediment traps with open check dams: a review, part I: hydraulic and deposition processes. (Accepted by the) Journal of Hydraulic Engineering 1-23 (2015). 3.Le Guern, J. Ms Thesis: Modélisation physique des plages de depot : analyse de la dynamique de remplissage.(2014) . 4.Carbonari, C. Ms Thesis: Small scale experiments of deposition processes occuring in sediment traps, LS-PIV measurments and geomorphological descriptions. (in preparation).

  14. Ways of removal of legislative and regulatory contradictions in sphere of small-scale business state administration

    OpenAIRE

    Mytnyk, Ulyana Mykolayivna

    2011-01-01

    Author investigated the problems of small-scale business state administration. The legislative and regulatory basis which regulates the small-scale business management was considered in the article. Legislative and regulatory contradictions were revealed in sphere of small-scale business state administration. The ways of removal of the conflictness were offered.

  15. Architecture of small-scale fault zones in the context of the Leinetalgraben Fault System

    Science.gov (United States)

    Reyer, Dorothea; Philipp, Sonja L.

    2010-05-01

    local stress field so that it stops many joints. Well developed fracture networks are therefore in most cases limited to single layers. From the data we finally determined the structural indices of the fault zones, that is, the ratios of damage zone and fault zone widths. By their nature structural indices can obtain values from 0 to 1; the values having implications for fault zone permeability. An ideal value of 0 would mean that a fault damage zone is absent. Such fault zones generally have low permeabilities as long as the faults are not active (slipping). A structural index of 1, however, would imply that there is practically no fault core and the fault zone permeability is entirely controlled by the fractures within the damage zone. Our measurements show that the damage zones of normal faults in the Muschelkalk limestone are relatively thick so that their structural indices are relatively high. In contrast to normal faults, reverse and strike-slip faults have smaller indices because of well developed brecciated fault cores. In addition we found that small-scale fault zones with parallel orientations to the major Leinetalgraben fault zones are more likely to have well developed damage zones than those with conjugate or perpendicular orientation. Our field data lead to the hypothesis that fault systems in the North German Basin may generally be surrounded by small-scale fault zones which have high permeabilities if orientated parallel to the major fault and lower permeabilities if conjugate or perpendicularly orientated. However, further studies of fault systems in different geological settings are needed to support or reject this hypothesis. Such studies help to improve the general understanding of fault zones and fault systems and thereby minimise the risk in matters of the exploitation of fault-related geothermal reservoirs.

  16. Regulatory potential for increasing small scale grid connected photovoltaic (PV) deployment in Australia

    International Nuclear Information System (INIS)

    The last decade has seen significant innovation and change in regulatory incentives to support photovoltaic deployment globally. With high fossil fuel dependency and abundant solar resource availability in Australia, grid connected photovoltaics are a viable low carbon technology option in existing electricity grids. Drawing on international examples, the potential to increase grid PV deployment through government response and regulation is explored. For each renewable energy certificate (REC) earned by small scale photovoltaics until 2012, the market provides four additional certificates under the current banded renewable targets. Our analysis indicates that REC eligibility is not accurately estimated currently, and an energy model is developed to calculate the variance. The energy model estimates as much as 26% additional REC's to be obtained by a 3 kWp PV system, when compared to the currently used regulatory method. Moreover, the provision of REC's increases benefits to PV technologies, in the process distorting CO2 abatement (0.21 tonne/REC) by 68%, when PV displaces peaking natural gas plants. Consideration of the secondary effects of a banded structure on emissions trading market is important in the context of designing a range of initiatives intended to support a transition to a low carbon electricity sector. - Research Highlights: →Grid connected photovoltaics hedge spikes in peak demand summer electricity prices. →Nationwide feed in tariff and new building regulations needed to increase PV deployment. →Australia has transitioned from a solar rebate to a banded solar credit structure. →The currently used regulatory deeming method underestimates REC eligibility by 27%. →The banded structure can potentially distort CO2 abatement by as much as 68%.

  17. Resolving the Fan-Spine Reconnection Geometry of a Small-Scale Chromospheric Jet Event with the New Solar Telescope

    CERN Document Server

    Zeng, Zhicheng; Ji, Haisheng; Goode, Philip R; Cao, Wenda

    2016-01-01

    Jets present ubiquitously in both quiet and active regions on the Sun. They are widely believed to be driven by magnetic reconnection. A fan-spine structure has been frequently reported in some coronal jets and flares, regarded as a signature of ongoing magnetic reconnection in a topology consisting of a magnetic null connected by a fan-like separatrix surface and a spine. However, for small-scale chromospheric jets, clear evidence of such structures is rather rare, although they are implied in earlier works that show an inverted-Y-shaped feature. Here we report high-resolution (0$"$.16) observations of a small-scale chromospheric jet obtained by the New Solar Telescope (NST) using 10830~{\\AA} filtergrams. Bi-directional flows were observed across the separatrix regions in the 10830~\\AA{} images, suggesting that the jet was produced due to magnetic reconnection. At the base of the jet, a fan-spine structure was clearly resolved by the NST, including the spine and the fan-like surface, as well as the loops bef...

  18. Assessing the Efficiency of Small-Scale and Bottom Trawler Vessels in Greece

    Directory of Open Access Journals (Sweden)

    Dario Pinello

    2016-07-01

    Full Text Available This study explores the technical and scale efficiency of two types of Greek fishing vessels, small-scale vessels and bottom trawlers, using a bias-corrected input-oriented Data Envelopment Analysis model. Moreover, the associations between efficiency scores and vessel’s and skipper’s characteristics are also explored. The results indicate that small-scale vessels achieve a very low average technical efficiency score (0.42 but a much higher scale efficiency score (0.81. Conversely, bottom trawlers achieve lower scale but higher technical efficiency scores (0.68 and 0.73, respectively. One important finding of this study is that the technical efficiency of small-scale vessels, in contrast to trawlers, is positively associated with the experience of the skipper. In a looser context, it can be said that small-scale fisheries mainly rely on skill, whereas bottom trawlers rely more on technology. This study concludes that there is space for improvement in efficiency, mainly for small-scale vessels, which could allow the achievement of the same level of output by using reduced inputs.

  19. A small-scale study of magneto-rheological track vibration isolation system

    Science.gov (United States)

    Li, Rui; Mu, Wenjun; Zhang, Luyang; Wang, Xiaojie

    2016-04-01

    A magneto-rheological bearing (MRB) is proposed to improve the vibration isolation performance of a floating slab track system. However, it's difficult to carry out the test for the full-scale track vibration isolation system in the laboratory. In this paper, the research is based on scale analysis of the floating slab track system, from the point view of the dimensionless of the dynamic characteristics of physical quantity, to establish a small scale test bench system for the MRBs. A small scale MRB with squeeze mode using magneto-rheological grease is designed and its performance is tested. The major parameters of a small scale test bench are obtained according to the similarity theory. The force transmissibility ratio and the relative acceleration transmissibility ratio are selected as evaluation index of system similarity. Dynamics of these two similarity systems are calculated by MATLAB experiment. Simulation results show that the dynamics of the prototype and scale models have good similarity. Further, a test bench is built according to the small-scale model parameter analysis. The experiment shows that the bench testing results are consistency with that of theoretical model in evaluating the vibration force and acceleration. Therefore, the small-scale study of magneto-rheological track vibration isolation system based on similarity theory reveals the isolation performance of a real slab track prototype system.

  20. A new submm source within a few arcseconds of $\\alpha$ Centauri: ALMA discovers the most distant object of the solar system

    CERN Document Server

    Liseau, R; O'Gorman, E; Bertone, E; Chavez, M; De la Luz, V

    2015-01-01

    The understanding of the formation of stellar and planetary systems requires the understanding of the structure and dynamics of their outmost regions, where large bodies are not expected to form. Serendipitous searches for Sedna-like objects allows the observation of regions that are normally not surveyed. The Atacama Large Millimeter/submillimeter Array (ALMA) is particularly sensitive to point sources and it presents currently the only means to detect Sedna-like objects far beyond their perihelia. ALMA observations 10 months apart revealed a new blackbody point source that is apparently comoving with $\\alpha$ Cen B. We exclude that source to be a sub-/stellar member of the $\\alpha$ Centauri system, but argue that it is either an extreme TNO, a Super-Earth or a very cool brown dwarf in the outer realm of the solar system.

  1. HF doppler sounder measurements of the ionospheric signatures of small scale ULF waves

    Science.gov (United States)

    Baddeley, L. J.; Yeoman, T. K.; Wright, D. M.

    2005-07-01

    An HF Doppler sounder, DOPE (DOppler Pulsation Experiment) with three azimuthally-separated propagation paths is used to provide the first statistical examination of small scale-sized, high m waves where a direct measurement of the azimuthal wavenumber m, is made in the ionosphere. The study presents 27 events, predominantly in the post-noon sector. The majority of events are Pc4 waves with azimuthal m numbers ranging from 100 to 200, representing some of the smallest scale waves ever observed in the ionosphere. 4 Pc5 waves are observed in the post-noon sector. The fact that measurements for the wave azimuthal m number and the wave angular frequency are available allows the drift-bounce resonance condition to be used to hypothesise potential particle populations which could drive the waves through either a drift or drift-bounce resonance interaction mechanism. These results are compared with the statistical study presented by Baddeley et al. (2004) which investigated the statistical likelihood of such driving particle populations occurring in the magnetospheric ring current. The combination of these two studies indicates that any wave which requires a possible drift resonance interaction with particles of energies >60 keV, is statistically unlikely to be generated by such a mechanism. The evidence presented in this paper therefore suggests that in the pre-noon sector the drift-bounce resonance mechanism is statistically more likely implying an anti-symmetric standing wave structure while in the post-noon sector both a drift or drift-bounce resonance interaction is statistically possible, indicating both symmetric and anti-symmetric standing mode structures. A case study is also presented investigating simultaneous observations of a ULF wave in ground magnetometer and DOPE data. The event is in the lower m range of the statistical study and displays giant pulsation (Pg) characteristics. Keywords. Ionosphere (Ionosphere-magnetosphere interactions) Magnetospheric

  2. Small Scale Effect on Thermal Vibration of Single-Walled Carbon Nanotubes with Nonlocal Boundary Condition

    Directory of Open Access Journals (Sweden)

    Li Ming

    2013-03-01

    Full Text Available In this study, a single beam model has been developed to analyze the thermal vibration of Single-Walled Carbon Nanotubes (SWCNT. The nonlocal elasticity takes into account the effect of small size into the formulation and the boundary condition. With exact solution of the dynamic governing equations, the thermal-vibrational characteristics of a cantilever SWCNT are obtained. Influence of nonlocal small scale effects, temperature change and vibration modes of the CNT on the frequency are investigated. The present study shows that the additional boundary conditions from small scale do not change natural frequencies at different temperature change. Thus for simplicity, one can apply the local boundary condition to replace the small scale boundary condition.

  3. A Review of Milk Production in Pakistan with Particular Emphasis on Small-scale Producers

    OpenAIRE

    Garcia, Otto; Mahmood, Kalid; Hemme, Torsten

    2003-01-01

    The purpose of the study is to assess the economics of dairy farming in Pakistan and the prospects for improving the dairy income for small-scale producers, which currently form the backbone of the dairy industry. The document begins with a general overview of milk production in the country, followed by a detailed study of dairy farming in the province of Punjab, with a particular focus on the small-scale producers. Preliminary estimates of the margins in the formal and informal market for li...

  4. Micro-level practices to adapt to climate change for African small-scale farmers:

    OpenAIRE

    Below, Till; ARTNER Astrid; Siebert, Rosemarie; SIEBER STEFAN

    2010-01-01

    This paper discusses micro-level practices for adapting to climate change that are available to small-scale farmers in Africa. The analysis is based on a review of 17 studies about practices that boost small-scale farmers¿ resilience or reduce their vulnerability to observed or expected changes in climate; it includes data from more than 16 countries in Africa, the Americas, Europe, and Asia. The review shows that African smallholders are already using a wide variety of creative practices to ...

  5. Evaluating Technical Efficiency of Small-scale Pineapple (Ananas comosus) Production in Bureti District, Kenya

    OpenAIRE

    Walter Koech; Gicuru K. Ithinji; Lawrence K. Kibet

    2013-01-01

    Kenya has been one of the world’s leading pineapple producers for many years and is currently ranked 9th internationally. The biggest source of fruit is at Del Monte’s farm in Thika, but small-scale growers are also increasing their production for the local market. However, in Bureti District there is a gap between the potential farm yield and the actual yield realized by the pineapple farmers. Thus, this study has examined questions on current farm level efficiency in small-scale pineapple p...

  6. Preferential Sampling and Small-Scale Clustering of Gyrotactic Microswimmers in Turbulence

    Science.gov (United States)

    Gustavsson, K.; Berglund, F.; Jonsson, P. R.; Mehlig, B.

    2016-03-01

    Recent studies show that spherical motile microorganisms in turbulence subject to gravitational torques gather in down-welling regions of the turbulent flow. By analyzing a statistical model we analytically compute how shape affects the dynamics, preferential sampling, and small-scale spatial clustering. We find that oblong organisms may spend more time in up-welling regions of the flow, and that all organisms are biased to regions of positive fluid-velocity gradients in the upward direction. We analyze small-scale spatial clustering and find that oblong particles may either cluster more or less than spherical ones, depending on the strength of the gravitational torques.

  7. A small scale magnetically levitated train for project-based laboratory education

    Directory of Open Access Journals (Sweden)

    Glehn Gregor

    2015-12-01

    Full Text Available The drive train of a small scale magnetically levitated train reveals the principles of a mechatronic system and offers challenges related to design, construction and control. Therefore, it is used at the Institute of electrical Machines (IEM of the RWTH Aachen University as a demonstrator for engineering solutions. Instead of being a part of a static predefined student laboratory, the small scale magnetically levitated train is part of dynamic individual student projects. This approach provides the advantage that the students are directly involved in the engineering process and gain motivation out of their personal ideas becoming reality.

  8. Conversion of fracture toughness testing values from small scale three point bending test specimens to small scale yielding state (SSY) by elastic-plastic stress analysis; Murtumissitkeyden laskeminen pienen taivutuspalkin kokeesta

    Energy Technology Data Exchange (ETDEWEB)

    Ikonen, K. [Technical Research Centre of Finland, Espoo (Finland). Nuclear Engineering Lab.

    1993-07-01

    The report describes the work performed for achieving readiness to calculate fracture toughness dependence on dimension effects and loading conditions in fracture test specimens and real structures. In the report two- and three-dimensional computer codes developed and calculational methods applied are described. One of the main goals is to converse fracture toughness from small scale three point bending test specimens to case of a depth crack in plane strain i.e. to small scale yielding state (SSY) by numerical elastic-plastic stress analysis. Thickness effect of a test specimens and effect of a crack depth are separately investigated. Tests of three point bending specimens with and without sidegrooves and curved crack front are numerically simulated and experimental and computed results are compared. J-integral is calculated along crack front and also from force-deflection dependence of the beam. For the analyses the computing system was thoroughly automatized. Measuring capacity of three point bending test specimens was tried to evaluate. (orig.) (7 refs., 54 figs.).

  9. Managing Sustainable Development Conflicts: The Impact of Stakeholders in Small-Scale Hydropower Schemes

    Science.gov (United States)

    Watkin, Laura Jane; Kemp, Paul S.; Williams, Ian D.; Harwood, Ian A.

    2012-06-01

    The growing importance of the environment and its management has simultaneously emphasized the benefits of hydroelectric power and its environmental costs. In a changing policy climate, giving importance to renewable energy development and environmental protection, conflict potential between stakeholders is considerable. Navigation of conflict determines the scheme constructed, making sustainable hydropower a function of human choice. To meet the needs of practitioners, greater understanding of stakeholder conflict is needed. This paper presents an approach to illustrate the challenges that face small-scale hydropower development as perceived by the stakeholders involved, and how they influence decision-making. Using Gordleton Mill, Hampshire (UK), as an illustrative case, soft systems methodology, a systems modeling approach, was adopted. Through individual interviews, a range of problems were identified and conceptually modeled. Stakeholder bias towards favoring economic appraisal over intangible social and environmental aspects was identified; costs appeared more influential than profit. Conceptual evaluation of the requirements to meet a stakeholder-approved solution suggested a complex linear systems approach, considerably different from the real-life situation. The stakeholders introduced bias to problem definition by transferring self-perceived issues onto the project owner. Application of soft systems methodology caused a shift in project goals away from further investigation towards consideration of project suitability. The challenge of sustainable hydropower is global, with a need to balance environmental, economic, and social concerns. It is clear that in this type of conflict, an individual can significantly influence outcomes; highlighting the need for more structured approaches to deal with stakeholder conflicts in sustainable hydropower development.

  10. Assessing the Sustainability of Different Small-Scale Livestock Production Systems in the Afar Region, Ethiopia

    Directory of Open Access Journals (Sweden)

    Ngufor L. Atanga

    2013-12-01

    Full Text Available Livestock production is a key income source in eastern Africa, and 80% of the total agricultural land is used for livestock herding. Hence, ecological and socio-economically sustainable rangeland management is crucial. Our study aimed at selecting operational economic, environmental and social sustainability indicators for three main pastoral (P, agro-pastoral (AP, and landless intensive (LI small scale livestock production systems for use in sustainability assessment in Ethiopia. Quantitative and qualitative data were collected through grey literature and semi-structured interviews, assessing livestock and feed resources, production technology, land tenure, financial and gender issues. Our results suggested that feed shortages (FS are directly related to grazing pressure (G and inversely related to grass recovery rates (R. According to our indicators, AP was the most sustainable while P and LI were only conditionally sustainable production systems. 93% of 82 interviewees claimed that private land ownership was the best land tenure incentive for efficient rangeland management. Farmers perceived Prosopis juliflora expansion, sporadic rainfall, and disease infestation as the most significant causes for decreasing livestock productivity. Landless intensive farmers had the highest equality in income distribution (Gini Index: GI = 0.4, followed by P and AP (each with a GI = 0.5. Neither educational background nor income seemed to determine grazing species conservation efforts. We claimed that sustainability indicators are valuable tools to highlight shortcomings and strengths of the three main livestock production systems and help with future livestock management in Ethiopia. Selecting suitable indicators, however, is crucial as data requirements and availability can vary across livestock systems.

  11. Palms, peccaries and perturbations: widespread effects of small-scale disturbance in tropical forests

    Directory of Open Access Journals (Sweden)

    Queenborough Simon A

    2012-03-01

    -restricted, impact on juvenile plants, most likely on the survival and growth of seedlings and saplings damaged by foraging peccaries. Given the abundance of fruit produced by each palm, the widespread effects of these small-scale disturbances appear, over long time-scales, to cause directional changes in community structure at larger scales.

  12. Progress in generating fracture data base as a function of loading rate and temperature using small-scale tests

    International Nuclear Information System (INIS)

    Structural integrity assessment of nuclear pressure vessels requires small specimen fracture testing to generate data over a wide range of material loading, and temperature conditions. Small scale testing is employed since extensive testing is required including small radiation embrittled samples from nuclear surveillance capsules. However, current small scale technology does not provide the needed dynamic fracture toughness relevant to the crack arrest/reinitiation events that may occur during pressurized thermal shock transients following emergency shutdown. This paper addresses the generation of this much needed dynamic toughness data using a novel experimental-computational approach involving a coupled pressure bars (CPB) technique and a viscoplastic dynamic fracture code. CPB data have been generated to testing temperatures never before reached: 37 to 100 degrees C -- 60 to 123 degrees C above the nil ductility transition temperature. Fracture behavior of pressure vessel steel from lower shelf to upper shelf temperatures and previous toughness estimates for the 106 MPa√m s-1 loading rate regime are assessed in light of the new CPB data. 26 refs., 14 figs., 3 tabs

  13. Application Closed-End Oscillating Heat Pipe for Essential Oil Condensation of the Small Scale Essential Oil Refiner

    Directory of Open Access Journals (Sweden)

    Sakultala WANNAPAKHE

    2013-12-01

    Full Text Available This research aimed to investigate the design and building of a small scale essential oil refiner by using heat pipes for essential oil condensation. The device structure of the small scale essential oil refiner was divided into 3 sections as follows: 1 the boiler with a heater for heating, 2 the vapor tube, and 3 the condenser unit. Three patterns of condenser unit were investigated: 1 condensation by water circulation, 2 condensation using heat pipes, and 3 condensation using heat pipes with water circulation. The temperature for testing was 80, 90 and 100 °C. A closed-end oscillating heat pipe (CEOHP was used in this research. The inner diameter of the heat pipe was 2 mm. R123 was used as the working fluid. 500 g of kaffir lime peels were used for each test with a time of 2 hours. It was found that the highest quantity of essential oil was 1.4 cc when using a CEOHP with a water circulation unit at 100 °C.

  14. Factors influencing the use of improved farm practices among small-scale farmers in Kano State of Nigeria

    Directory of Open Access Journals (Sweden)

    Oyewole S. O.

    2015-01-01

    Full Text Available This study evaluates the factors influencing the use of improved farm practices among small-scale farmers in Kano State. Data were obtained from 110 farmers with the aid of structured questionnaire. Data were analysed using descriptive statistics and multiple regression analysis. The results showed that 73.6 of the respondents are in the range of 20 to 50 years which is the active age range. The mean age of respondents was 40 years. It was revealed that 80.9% of the respondents have farming experience of more than 10 years. About 15% had above primary education. The use of pesticides and herbicides among farmers is accounted for 77.3% of the respondents. The results also revealed that 74.5 and 80.9% of the farmers are aware and have adopted the use of improved seeds and animal traction respectively. The results further revealed that level of education and extension contact were positively and significantly influential to the use of improved farm practices. The study therefore recommends improved extension linkages to sensitize small-scale farmers on the need to adopt improved farm practices.

  15. Can Cultivars from participatory plant breeding improve seed provision to small-scale farmers?

    NARCIS (Netherlands)

    Almekinders, C.J.M.; Thiele, G.; Danial, D.L.

    2007-01-01

    Seed provision for small-scale farmers deals with multiple constraints. These include, on the supply side, high seed production costs and poor adaptedness of the cultivars, and on the demand side, anticyclical demand and low and variable sales. Approaches to improve seed provision to this sector of

  16. Performance of a small scale prototype of cellular honeycomb proportional chamber

    CERN Document Server

    Ahammed, Z; CERN. Geneva; Bhati, A K; Chattopadhyay, S; Dubey, A K; Dutta Mazumdar, M R; Mahapatra, D P; Ganti, M S; Nayak, T K; Singaraju, R N; Trivedi, M D; Viyogi, Y P; Aggarwal, M M

    1999-01-01

    Beam test results for the first small-scale prototype of a honeycomb cellular proportional chamber to be used in ALICE PMD are presented. The overall efficiency for MIP detection is found to be around 93%. The efficiency drops to about 75% at the corners of the hexagon. Improvement in design is suggested.

  17. Assessment of Small-scale Buffalo Milk Dairy Production-A Premise for a Durable Development

    Directory of Open Access Journals (Sweden)

    Marian MIHAIU

    2012-05-01

    Full Text Available Buffalo husbandry is an important source of income for a number of small-scale producers in Romania that is why an assessment of its� product�s quality is much needed for improvement and evaluation of their vulnerability to international competition. In order to ascertain possible developments in the buffalo dairy sector and to broadly identify areas of intervention that favor small-scale dairy producers, the study examined the potential to improve buffalo milk production by evaluating its authenticity and hygienic quality. The methods used involved the molecular testing (PCR-technique for identifying cow, sheep or goat DNA in the dairy products� samples collected from the small-scale producers market. The hygienic quality of these samples was determined through classical microbiology methods, highly developed techniques (Trek System and PCR for bacterial species confirmation. The results showed that a high percent (65%, from the products found were adulterated with other species milk, mostly cow milk. The most commonly falsified buffalo dairy products were the cheese and the traditional product �telemea�. The prevalence of the bacterial species identified belonged to Listeria innocua and Listeria welshmeri. The conclusion of this study is the need of a durable development system in this particular dairy chain to improve and assure the authenticity and quality of the small-scale producers� products and their reliability for the consumers.

  18. Acoustic assessment of small-scale military-style nozzles with chevrons

    NARCIS (Netherlands)

    Kuo, C.-W.; Veltin, J.; McLaughlin, D.K.

    2012-01-01

    With the emergence of more powerful fighter aircraft, supersonic jet noise reduction devices are being intensively researched. Small-scale measurements are a crucial step in evaluating the potential of noise reduction concepts at an early stage in the design process. With this in mind, the present s

  19. Fostering sustainable small-scale investments: lessons from experience and ideas for intervention and innovation

    International Nuclear Information System (INIS)

    This article presents lessons from experience pertinent to implementing small-scale natural resource and related investment projects in developing countries. It outlines ideas for intervention and innovation to foster such investments. Particular emphasis is placed on private-sector participation in these investments. Following a brief presentation of the economic development and other arguments that support intervention and innovation in support of such small-scale natural resource investments, the article discusses many of the lessons learned from experience. These lessons reinforce those touched upon in the investment-specific discussions in the previous articles. The experience and associated lessons that are examined include experiences in both developing and developed countries and encompass nor just lessons from natural resource investments, but also small-scale investments in other sectors. Financing and other innovations which facilitate meeting the challenges are drawn from relevant experience where barriers to investment have been surmounted. Options for programme and project interventions to increase market penetration of small-scale investments and achieve the associated development linkages and synergies are suggested. These suggestions are aimed especially at governments and bilateral and multilateral development finance and development assistance entities. It is those players who might support such interventions in collaboration with local financial institutions and other market players. (author)

  20. Inclusion of small-scale milk producers in modern dairy value chains

    NARCIS (Netherlands)

    Wouters, A.P.; Lee, van der J.

    2010-01-01

    The worldwide demand for milk is ever-increasing. The question we address here is how small-scale milk producers, mainly based in developing countries, can participate in modern dairy value chains? First, markets should have the preconditions of a reliable market, a competitive milk price and access

  1. Small-Scale Bullying Prevention Discussion Video for Classrooms: A Preliminary Evaluation

    Science.gov (United States)

    Migliaccio, Todd; Raskauskas, Juliana

    2013-01-01

    Bullying has been shown to be negatively related to both academic performance and attendance among students. The present study examined a small-scale bullying intervention using a video-discussion model. Eighty-one students in grades 4 through 6 completed pre- and posttests examining gains in knowledge of bullying and responses to it. Results…

  2. Employability and Technical Skill Required to Establish a Small Scale Automobile Workshop

    Science.gov (United States)

    Olaitan, Olawale O.; Ikeh, Joshua O.

    2015-01-01

    The study focused on identifying the employability and technical skills needed to establish small-scale automobile workshop in Nsukka Urban of Enugu State. Five purposes of the study were stated to guide the study. Five research questions were stated and answered in line with the purpose of the study. The population for the study is 1,500…

  3. A review of mercury exposure among artisanal small-scale gold miners in developing countries

    DEFF Research Database (Denmark)

    Kristensen, Anders Kasper Bruun; Thomsen, Jane Frølund; Mikkelsen, Sigurd

    2014-01-01

    Extraction of gold using mercury has been a way out of poverty for millions of people in developing countries. Artisanal small-scale gold mining (ASGM) has expanded during the last decades and is often carried out under primitive conditions. Thus, workers in this industry may be exposed to high...

  4. Prepublishing the Topics for a Test of Writing Skills: A Small-Scale Simulation.

    Science.gov (United States)

    Powers, Donald E.; And Others

    1993-01-01

    A small-scale simulation investigated the impact of making essay topics available to test takers before the test. Results with 11 college students reveal little effect of the prepublished topic. Implications for teacher licensure examinations are discussed with reference to the Praxis Series: Professional Assessments for Beginning Teachers being…

  5. Small-Scale Testing of Cyclic Laterally Loaded Monopiles in Dense Saturated Sand

    DEFF Research Database (Denmark)

    Nicolai, Giulio; Ibsen, Lars Bo

    2014-01-01

    loading are issues that should be investigated. In the present work, a small-scale test campaign of a stiff pile was performed in order to validate methodologies proposed by recent studies. Cyclic loading was not found to degrade the ultimate static resistance of the pile, which contrasts with current...

  6. Detecting Answer Copying Using Alternate Test Forms and Seat Locations in Small-Scale Examinations

    Science.gov (United States)

    van der Ark, L. Andries; Emons, Wilco H. M.; Sijtsma, Klaas

    2008-01-01

    Two types of answer-copying statistics for detecting copiers in small-scale examinations are proposed. One statistic identifies the "copier-source" pair, and the other in addition suggests who is copier and who is source. Both types of statistics can be used when the examination has alternate test forms. A simulation study shows that the…

  7. Small scale agriculture, marginal conditions and market access: impacts on natural resources and farmers' welfare

    NARCIS (Netherlands)

    Cavatassi, R.

    2010-01-01

    Keywords: small-scale farmers, food security, impact evaluation, Ecuador, Ethiopia, crop choice, social capital, crop genetic diversity, pesticides. Numerous are the obstacles and difficulties smallholder farmers from developing countries have to face to achieve food security or improve their well

  8. Musculoskeletal pain in women working in small-scale agriculture in South Africa.

    NARCIS (Netherlands)

    Naidoo, S.; Kromhout, H.; London, L.; Naidoo, R.N.; Burdorf, A.

    2009-01-01

    BACKGROUND: Musculoskeletal pain is associated with demographic, occupational and physical factors. METHODS: Our study investigated the prevalence and factors associated with musculoskeletal pain in 911 women working in small-scale agriculture in rural northern KwaZulu-Natal, South Africa in 2006 us

  9. Distribution of trematodes in snails in ponds at integrated small-scale aquaculture farms

    NARCIS (Netherlands)

    Boerlage, A.S.; Graat, E.A.M.; Verreth, J.A.J.; Jong, de M.C.M.

    2013-01-01

    In integrated small-scale aquaculture farming, animal and human excreta maybe used as fish feed and pond fertilizer, thereby enhancing transmission of fish-borne zoonotic trematodes (FZTs) from final hosts, like humans, pigs and chickens, to snails. Areas within a pond could vary in trematode egg-lo

  10. Fuel From Farms: A Guide to Small-Scale Ethanol Production.

    Science.gov (United States)

    Solar Energy Research Inst., Golden, CO.

    Ethanol and blends of ethanol and gasoline (such as gasohol) offer a near-term fuel alternative to oil. The focus of this handbook is upon the small-scale production of ethanol using farm crops as the source of raw materials. Provided are chapters on ethanol production procedures, feedstocks, plant design, and financial planning. Also presented…

  11. Air pollution and economics: Alternate use of fuels in small scale industries

    International Nuclear Information System (INIS)

    In developing countries the problem of air pollution was recognized earlier, however, it has acquired a greater dimension due to the conventional use of low grade fuels like coal, baggase, rice husk, etc. having high sulphur and ash content. The industrial sources contribute about 30--40% of the total emissions. In India, the small scale industries (low investment group) contribute about 60--80% of the total industrial emissions. These industries are characterized with various environmental pollution problems due to cluster of small scale industries located in sensitive area; use of low grade fuel, primitive processing techniques without emission abatement facilities etc., thus leading to enormous pollution in an confined region. Acute need was felt to reduce the pollution problem associated with small scale industries by use of cleaner fuel so as to reduce the localized problem. The paper presents the emissions associated with use of coal/coke, natural gas, LPG, and propane along with the fuel cost for small scale industrial sector of Agra, Firozabad and Mathura region. The studies carried out would find applicability to meet the air pollution standards based on shift in fuel and associated cost

  12. Energetic Materials Center Report--Small-Scale Safety and Thermal Testing Evaluation of Butyl Nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Peter C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Reynolds, John G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center

    2013-04-26

    Butyl Nitrate (BN) was examined by Small-Scale Safety and Thermal (SSST) Testing techniques to determine its sensitivity to impact, friction, spark and thermal exposure simulating handling and storage conditions. Under the conditions tested, the BN exhibits thermal sensitivity above 150 °C, and does not exhibit sensitive to impact, friction or spark.

  13. Small-scale, hydrogen-oxidizing-denitrifying bioreactor for treatment of nitrate-contaminated drinking water

    Science.gov (United States)

    Nitrate removal by hydrogen-coupled denitrification was examined using flow-through, packed-bed bioreactors to develop a small-scale, cost effective system for treating nitrate-contaminated drinking-water supplies. Nitrate removal was accomplished using a Rhodocyclus sp., strain HOD 5, isolated fro...

  14. Towards systematic planning of small-scale hydrological intervention-based research

    Science.gov (United States)

    Pramana, K. E. R.; Ertsen, M. W.; van de Giesen, N. C.

    2015-09-01

    Many small-scale water development initiatives are accompanied by hydrological research to study either the shape of the intervention or its impacts. Humans influence both, and thus one needs to take human agency into account. This paper focuses on the effects of human actions in the intervention and its associated hydrological research, as these effects have not yet been discussed explicitly in a systematic way. In this paper, we propose a systematic planning, based on evaluating three hydrological research projects in small-scale water intervention projects in Vietnam, Kenya, and Indonesia. The main purpose of the three projects was to understand the functioning of interventions in their hydrological contexts. Aiming for better decision-making on hydrological research in small-scale water intervention projects, we propose two analysis steps: (1) being prepared for surprises and (2) cost-benefit analysis. By performing the two analyses continuously throughout a small-scale hydrological intervention based project, effective hydrological research can be achieved.

  15. Physico-chemical treatment of wastewater from clusters of small scale cotton textile units.

    Science.gov (United States)

    Pathe, P P; Biswas, A K; Rao, N N; Kaul, S N

    2005-03-01

    Small scale industries can not own individual wastewater treatment facility due to non-availability of land and skilled manpower for operation and maintenance of wastewater treatment plants. A centralized wastewater treatment facility for clusters of small scale industries is appropriate. This concept is gaining popularity in recent years. In India, various textile process operations are undertaken by individual small scale units. The wastewater generated at these units is conveyed to a common effluent treatment facility comprising of equalization, flocculation-clarification, activated sludge process, secondary clarification and finally discharge into inland surface water bodies. The wastewater from small scale cotton textile processing units was highly coloured and alkaline with average BOD and COD concentration of 205 and 790 mg l(-1), respectively. Due to the presence of several dyes, particularly reactive dyes, the biological treatment is often found less effective. Therefore, applicability of various physico-chemical treatment methods needs to be investigated in pursuit of an alternative to biological treatment of textile wastewater. A physico-chemical treatment scheme, involving chemical coagulation-sedimentation, dual media filtration, activated carbon adsorption followed by chemical oxidation was investigated in this paper. The quality of final treated wastewater in terms of BOD and COD was 18-24 and 230-240 mg l(-1), respectively through this scheme. A scheme of treatment comprising coagulation-sedimentation, dual media filtration, activated carbon, chemical oxidation may be considered as an alternative to biological treatment of textile wastewater. PMID:15881028

  16. A small scale cell culture system to analyze mechanobiology using reporter gene constructs and polyurethane dishes

    DEFF Research Database (Denmark)

    Seefried, Lothar; Mueller-Deubert, Sigrid; Wentzer, Thomas Schwarz;

    2010-01-01

    molecular mechanisms of mechanotransduction and its crosstalk with biochemically induced signal transduction, AP1 and SP1 luciferase reporter gene constructs were cloned and transfected into various cell lines and primary cells. A newly developed bioreactor and small-scale 24-well polyurethane dishes were...

  17. Local adaptation of the clonal plant Ranunculus reptans to flooding along a small-scale gradient

    NARCIS (Netherlands)

    Lenssen, J.P.M.; Kleunen, M. van; Fischer, M.; Kroon, J.C.J.M. de

    2004-01-01

    1 Plant species are known to segregate along small-scale flooding gradients. We tested whether differences in flooding duration can also result in genetic differentiation in the clonal species Ranunculus reptans, which naturally grows in both a lakeside microhabitat and a landside microhabitat with

  18. Design study of coated conductor direct drive wind turbine generator for small scale demonstration

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Jensen, Bogi Bech

    2012-01-01

    We have investigated the properties of a superconducting direct drive generator suitable for demonstration in a small scale 11 kW wind turbine. The engineering current density of the superconducting field windings is based on properties of coated conductors wound into coils holding of the order 6...

  19. Evaluation of real-time operating system for small-scale embedded systems

    International Nuclear Information System (INIS)

    In this paper, the performance of some real-time operating systems for small-scale embedded systems are evaluated based on some criteria. The evaluation is performed qualitatively and quantitatively. The evaluation results based on a case study on an engineering application will be presented. (author)

  20. Aquaponics - how to build your own food producing, small scale, aquaponics system

    NARCIS (Netherlands)

    Ros, J.

    2015-01-01

    This "designers' manual" is made during the TIDO-course AR0531 Innovation and Sustainability This manual is made for people that want to create a small-scale sustainable way of retrieving food. At first it will be presented on how the system works and what it can benefit to your residence.

  1. A fast and simple branching algorithm for solving small scale fixed-charge transportation problem

    OpenAIRE

    Krzysztof Kowalski; Benjamin Lev; Wenjing Shen; Yan Tu

    2014-01-01

    In this paper, we develop a simple algorithm for obtaining the global solution to a small scale fixed-charge transportation problem (FCTP). The procedure itself is very quick. The proposed method solves FCTP by decomposing the problem into series of smaller sub-problems, which is novel and can be useful to researchers solving any size of the problem.

  2. "It's Really Making a Difference": How Small-Scale Research Projects Can Enhance Teaching and Learning

    Science.gov (United States)

    Dexter, Barbara; Seden, Roy

    2012-01-01

    Following an internal evaluation exercise, using Action Research, this paper identifies the positive impact of small-scale research projects on teaching and learning at a single case study UK University. Clear evidence is given of how the projects benefited students and staff, and enhanced institutional culture. Barriers to better practice are…

  3. “MAJOR PROBLEMS OF SMALL SCALE INDUSTRIAL UNITS IN KURNOOL DISTRICT, A.P, INDIA”

    OpenAIRE

    J. Sreenivasulu; C. Lakshmikantha Reddy

    2015-01-01

    Kurnool is the regarded as an industrially backward district in India. The rate of industrial development is reality low, through several measures have been initiated to accelerate industrial development in the district. These include offering investment subsidies, providing industrial infrastructure, extending vocational training support and offering concessional finances especially for the small and tiny units. The activitywise distribution of small scale units ar...

  4. Small-Scale Cyclic Tests on Nonslender Piles Situated in Sand

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo

    In the period from August 2011 till October 2011 a series of small-scale tests on pile foundations has been conducted at Aalborg University. In all the tests, the piles have been exposed to cyclic loading consisting of 20-25 load cycles and all the tests have been conducted in a pressure tank. Th...

  5. Small-Scale Quasi-Static Tests on Non-Slender Piles Situated in Sand

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo

    In the period from February 2009 till March 2011 a series of small-scale tests on pile foundations has been conducted at Aalborg University. In all the tests the piles have been exposed to quasi-static loading and all the tests have been conducted in a pressure tank. The objective of the tests ha...

  6. Role of small-scale independent providers in water and sanitation

    NARCIS (Netherlands)

    M.P. van Dijk (Meine Pieter)

    2008-01-01

    textabstractSmall-scale independent providers (SSIPs) and households are good for 10–69% of the household water supply and sometimes up to 95% of the sanitation solutions in cities in developing countries. Different types of SSIP can be distinguished. They could be allowed to make a more important c

  7. Child Wasting in Emergency Pockets: A Meta-Analysis of Small-Scale Surveys from Ethiopia.

    Science.gov (United States)

    Altare, Chiara; Delbiso, Tefera Darge; Guha-Sapir, Debarati

    2016-02-01

    Child undernutrition is a major public health concern in Ethiopia (stunting national prevalence: 44%; wasting: 10%), despite the overall improvement in child health status during the last decade. Hundreds of small-scale surveys are conducted in Ethiopia's emergency pockets under ENCU's supervision. We reviewed the evidence from small-scale surveys conducted between 2008 and 2013 with two objectives: to provide a summary estimate of wasting prevalence from emergency pockets and to examine reasons for variation in prevalence estimates. We created a dataset by combining data from the Complex Emergency Database, the Famine Early Warning System Network and the Armed Conflict Location Event Data. We conducted a meta-analysis of small-scale surveys using a random effects model with known within-study heterogeneity. The influence of survey covariates on estimated prevalence was investigated with meta-regression techniques. We included 158 surveys in the analysis. A high degree of heterogeneity among surveys was observed. The overall estimate of wasting prevalence was 10.6% (95% CI 9.8-11.4), with differences among regions and between residents and refugees. Meta-regression results showed that vaccination coverage, child mortality, diarrhea prevalence and food insecurity are significantly associated with wasting prevalence. Child care and displacement status were not. Aggregated analysis of small-scale surveys provides insights into the prevalence of wasting and factors explaining its variation. It can also guide survey planning towards areas with limited data availability. PMID:26828512

  8. Technological adaptation and employment in the small-scale farm machinery industry: uttar pradesh, India.

    OpenAIRE

    Mishra, S. C.

    1985-01-01

    ILO pub-WEP pub. Working paper on industrial development, based on a sample of 81 small scale industries producing agricultural machinery in Uttar Pradesh, India - explains industries' stagnation due to failure to produce technological change and innovations; stresses need for marketing and publicity for inexpensive agricultural equipment rather than state subsidy to produce expensive tractors, etc. Bibliography, statistical tables.

  9. Irrigation Water Value at Small-scale Schemes: Evidence from the North West Province, South Africa

    NARCIS (Netherlands)

    Speelman, S.; Farolfi, S.; Perret, S.; Haese, D' L.; Haese, D' M.

    2008-01-01

    Insight into the value of water is essential to support policy decision making about investments in the water sector, efficient allocation of water and water pricing. However, information on irrigation water values at small-scale schemes is scarce and in general little attention is paid to the deter

  10. Economic, Environmental, and Social Evaluation of Africa's Small-Scale Fisheries

    OpenAIRE

    World Bank

    2015-01-01

    This report is the culmination of a cross-African countries analytical and empirical study commissioned by the World Bank, which set out to improve the understanding of the characteristics and environmental, economic, and social performances of small-scale fisheries in Africa. It applies a common evaluation tool, called Fishery Performance Indicators (FPIs), which evaluates the ecological,...

  11. Numerical simulation of small-scale mixing processes in the upper ocean and atmospheric boundary layer

    Science.gov (United States)

    Druzhinin, O.; Troitskaya, Yu; Zilitinkevich, S.

    2016-02-01

    The processes of turbulent mixing and momentum and heat exchange occur in the upper ocean at depths up to several dozens of meters and in the atmospheric boundary layer within interval of millimeters to dozens of meters and can not be resolved by known large- scale climate models. Thus small-scale processes need to be parameterized with respect to large scale fields. This parameterization involves the so-called bulk coefficients which relate turbulent fluxes with large-scale fields gradients. The bulk coefficients are dependent on the properties of the small-scale mixing processes which are affected by the upper-ocean stratification and characteristics of surface and internal waves. These dependencies are not well understood at present and need to be clarified. We employ Direct Numerical Simulation (DNS) as a research tool which resolves all relevant flow scales and does not require closure assumptions typical of Large-Eddy and Reynolds Averaged Navier-Stokes simulations (LES and RANS). Thus DNS provides a solid ground for correct parameterization of small-scale mixing processes and also can be used for improving LES and RANS closure models. In particular, we discuss the problems of the interaction between small-scale turbulence and internal gravity waves propagating in the pycnocline in the upper ocean as well as the impact of surface waves on the properties of atmospheric boundary layer over wavy water surface.

  12. ENTREPRENEURIAL LEADERSHIP: EMPLOYEE PERCEPTION AND ORGANIZATIONAL PERFORMANCE IN RURAL SMALL SCALE ENGINEERING INDUSTRY

    OpenAIRE

    Dilip Dnyandeo Jagdale; Sarang Shankar Bhola

    2015-01-01

    Entrepreneurial Leadership is a relatively new, sometimes controversial, andburgeoning field of management research. Significance of this concept is increasing day by day in entrepreneurship literature. Entrepreneur’s different leadership styles effect on performanceof the organizations. Present research investigates the impact of employee perceived EntrepreneurialLeadership style on Organizational Performance. Study is conducted with reference to RuralSmall Scale Engineering Industry i...

  13. Financial analysis of brucellosis control for small-scale goat farming in the Bajio Region, Mexico

    NARCIS (Netherlands)

    Oseguera Montiel, D.; Bruce, M.; Frankena, K.; Udo, H.M.J.; Zijpp, van der A.J.; Rushton, J.

    2015-01-01

    Brucellosis is an endemic disease in small-scale goat husbandry systems in Mexico. It is a zoonosis and the economic consequences can be large, although estimates are not available for the Mexican goat sector. Our objective was to conduct a financial analysis of brucellosis control in a prominent da

  14. Factors affecting Small-Scale Coffee Production in Githunguri District, Kenya

    Directory of Open Access Journals (Sweden)

    Margaret Njeri Gathura

    2013-09-01

    Full Text Available This study was carried out to determine the factors affecting small scale coffee production in Kenya. The establishments under study were small-scale coffee farms in Githunguri District.It was to determine whether marketing factors, finances, government policies and physical and human resources affect coffee production in Githunguri District. Primary sources included use of questionnaires, observation and interviews. Secondary sources included desk research, library research on journals, text books and factory publications. The target population was over 700,000 small-scale coffee producers in Kenya out of which the accessible population of 10,000 producers drawn from Githunguri District in Kiambu County was selected which a sample size of 120 respondents was sampled. Stratified sampling technique was employed to compare views among coffee producers from the various coffee societies in the area. Data analysis was both qualitative and quantitative using descriptive statistics. Data presentation was in form of tables to help interpret findings and generate conclusions that aided solutions to identified problems. The research established that marketing factors, finances, government policies and physical and human resources greatly affected coffee production. The study recommended that the government should encourage coffee production by formulating favorable marketing factors and other policies and provide finances to small scale coffee producers. Producers on the other hand should strive to provide conducive working environment to their workers so as to sustain them in their farms. This will help to improve coffee yields and quality.

  15. Workshop and Symposium on Sustainable Small-scale Fisheries: Towards FAO Guidelines on Marine and Inland Small-scale Fisheries, 19-21 September, 2011, Kolkata, West Bengal, India

    OpenAIRE

    2011-01-01

    The workshop and symposium titled Sustainable Small-scale Fisheries: Towards FAO Guidelines on Marine and Inland Small-scale Fisheries was jointly organized by the National Fishworkers’ Forum (NFF) and the Society for Direct Initiative for Social and Health Action (DISHA), in collaboration with the International Collective in Support of Fishworkers (ICSF). The workshop was the first in a series of consultations around the world organized to discuss the Voluntary Guidelines on Small-scale ...

  16. Atomistic modeling of nanowires, small-scale fatigue damage in cast magnesium, and materials for MEMS.

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Martin L. (University of Colorado, Boulder, CO); Talmage, Mellisa J. (University of Colorado, Boulder, CO); McDowell, David L., 1956- (,-Georgia Institute of Technology, Atlanta, GA); West, Neil (University of Colorado, Boulder, CO); Gullett, Philip Michael (Mississippi State University , MS); Miller, David C. (University of Colorado, Boulder, CO); Spark, Kevin (University of Colorado, Boulder, CO); Diao, Jiankuai (University of Colorado, Boulder, CO); Horstemeyer, Mark F. (Mississippi State University , MS); Zimmerman, Jonathan A.; Gall, K (Georgia Institute of Technology, Atlanta, GA)

    2006-10-01

    titled 'Atomistic Modeling of Nanowires, Small-scale Fatigue Damage in Cast Magnesium, and Materials for MEMS'. This project supported a strategic partnership between Sandia National Laboratories and the University of Colorado at Boulder by providing funding for the lead author, Ken Gall, and his students, while he was a member of the University of Colorado faculty.

  17. Atomistic modeling of nanowires, small-scale fatigue damage in cast magnesium, and materials for MEMS

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Martin L. [Univ. of Colorado, Boulder, CO (United States); Talmage, Mellisa J. [Univ. of Colorado, Boulder, CO (United States); McDowell, David L. [Georgia Inst. of Technology, Atlanta, GA (United States); West, Neil [Univ. of Colorado, Boulder, CO (United States); Gullett, Philip Michael [Mississippi State Univ., Mississippi State, MS (United States); Miller, David C. [Univ. of Colorado, Boulder, CO (United States); Spark, Kevin [Univ. of Colorado, Boulder, CO (United States); Diao, Jiankuai [Univ. of Colorado, Boulder, CO (United States); Horstemeyer, Mark F. [Mississippi State Univ., Mississippi State, MS (United States); Zimmerman, Jonathan A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gall, K. [Georgia Inst. of Technology, Atlanta, GA (United States)

    2006-10-01

    titled 'Atomistic Modeling of Nanowires, Small-scale Fatigue Damage in Cast Magnesium, and Materials for MEMS'. This project supported a strategic partnership between Sandia National Laboratories and the University of Colorado at Boulder by providing funding for the lead author, Ken Gall, and his students, while he was a member of the University of Colorado faculty.

  18. Confirming the transit of the Earth-mass planet orbiting Alpha Centauri B

    Science.gov (United States)

    Demory, Brice-Olivier

    2013-10-01

    One of the most fascinating exoplanet findings of the past years is undoubtedly the discovery of an Earth-mass exoplanet orbiting Alpha Centauri B. Alpha Cen Bb orbits one component of the closest stellar system to the Earth and has the potential to become a true Rosetta stone in exoplanet science, if its transiting nature were revealed. In 2013, we observed Alpha Centauri B during 16 orbits with HST/STIS to search for the transit of Alpha Cen Bb. We recently carried out in-depth photometric analyses of this dataset that resulted in the clear detection of a transit-shaped pattern. Several factors, however, prevent us from securing the planetary nature of the signal found in the STIS time-series. Now that we know where and when to look for, we propose to confirm the repeatability of this signal and to firmly establish Alpha Cen Bb's existence and tighten its physical and orbital properties. We base our observing strategy on the successful approach employed just one year ago with the same instrument. Until Aug 9th 2014, combination of HST available roll angles, Alpha Cen binary separation and position angle will match the nearly-ideal configuration we had in July 2013. It would even be possible to benefit from CVZ status from 24/7/2014 to 28/7/2014, in which one transit of Alpha Centauri Bb is expected. HST/STIS is the only facility able to confirm a transit from such a small planet at a high confidence level.

  19. Resolving the Fan-spine Reconnection Geometry of a Small-scale Chromospheric Jet Event with the New Solar Telescope

    Science.gov (United States)

    Zeng, Zhicheng; Chen, Bin; Ji, Haisheng; Goode, Philip R.; Cao, Wenda

    2016-03-01

    Jets are ubiquitously present in both quiet and active regions on the Sun. They are widely believed to be driven by magnetic reconnection. A fan-spine structure has been frequently reported in some coronal jets and flares, and has been regarded as a signature of ongoing magnetic reconnection in a topology consisting of a magnetic null connected by a fan-like separatrix surface and a spine. However, for small-scale chromospheric jets, clear evidence of such structures is rather rare, although it has been implied in earlier works that showed an inverted-Y-shaped feature. Here we report high-resolution (0.″16) observations of a small-scale chromospheric jet obtained by the New Solar Telescope (NST) using 10830 Å filtergrams. Bi-directional flows were observed across the separatrix regions in the 10830 Å images, suggesting that the jet was produced due to magnetic reconnection. At the base of the jet, a fan-spine structure was clearly resolved by the NST, including the spine and the fan-like surface, as well as the loops before and after the reconnection. A major part of this fan-spine structure, with the exception of its bright footpoints and part of the base arc, was invisible in the extreme ultraviolet and soft X-ray images (observed by the Atmosphere Imaging Assembly and the X-Ray Telescope, respectively), indicating that the reconnection occurred in the upper chromosphere. Our observations suggest that the evolution of this chromospheric jet is consistent with a two-step reconnection scenario proposed by Török et al.

  20. Giants in the globular cluster omega Centauri: dust production, mass loss and distance

    OpenAIRE

    McDonald, Iain; van Loon, Jacco Th.; Decin, Leen; Boyer, Martha L; Dupree, Andrea K.; Evans, Aneurin; Gehrz, Robert D.; Woodward, Charles E.

    2008-01-01

    We present spectral energy distribution modelling of 6875 stars in omega Centauri, obtaining stellar luminosities and temperatures by fitting literature photometry to state-of-the-art MARCS stellar models. By comparison to four different sets of isochrones, we provide a new distance estimate to the cluster of 4850 +/- 200 (random) +/- 120 (systematic error) pc, a reddening of E(B-V) = 0.08 +/- 0.02 +/- 0.02 mag and a differential reddening of Delta[E(B-V)] < 0.02 mag for an age of 12 Gyr. Sev...